CN112307845B - Optical detection device - Google Patents

Abstract

The invention discloses an optical detection device which comprises a light guide unit, a detection module and a light source. The detection module receives the detection light beam emitted from the light guide unit, and the detection module is provided with a field area on the first surface of the light guide unit. The light source projects a detection light beam to a preset area through the second surface of the light guide unit, wherein the detection light beam can be transmitted in the light guide unit in a total reflection mode, and an overlapping area exists between the preset area and the field area. When no finger of a user contacts on the preset area, the detection light beam is totally reflected in the field area. When a finger of a user contacts on the field area, the detection light beam is diffusely reflected at the fingerprint ridge contacted with the field area, and the detection light beam is totally reflected at the position opposite to the fingerprint valley in the field area. At least part of the diffusely reflected detection light beam passes through the light guide unit to be received by the detection module and converted into corresponding electric signals so as to obtain fingerprint information. The invention has better under-screen fingerprint detection effect.

Description

Optical detection device

Technical Field

The present invention relates to the field of optoelectronic technology, and in particular to an optical detection device for realizing fingerprint detection or other detection by using optical imaging.

Background technique

With the advancement of technology and the improvement of people's living standards, users require more functions and fashionable appearance for electronic products such as mobile phones, tablets, and cameras. At present, the development trend of electronic products such as mobile phones is to have a high screen-to-body ratio and functions such as fingerprint detection. In order to achieve a full-screen or near-full-screen effect and make electronic products have a high screen-to-body ratio, under-screen fingerprint detection technology has emerged. However, for non-self-luminous displays such as LCD screens, the existing technology does not have a good under-screen detection solution.

Summary of the invention

In view of this, the present invention provides an optical detection device that can solve the problems of the prior art.

One aspect of the present invention provides an optical detection device, comprising a light guide unit, comprising a first surface and a second surface; a detection module, located below the light guide unit, the first surface being the surface of the light guide unit facing away from the detection module, the detection module being used to receive a detection light beam emitted from the light guide unit, the detection module having a field of view area on the first surface; and a light source, being used to project the detection light beam into the interior of the light guide unit through the second surface, and the detection light beam entering the interior of the light guide unit can be transmitted by total reflection in the light guide unit, defining the detection light beam entering the interior of the light guide unit from the light source after being transmitted and first reaching the detection module. The area of the first surface is a preset area, and there is an overlapping area between the preset area and the field of view area, and the overlapping area accounts for an area ratio of greater than or equal to 30% of the field of view area; when the preset area is not touched by a user's finger, a detection light beam is totally reflected in the field of view area; when the field of view area is touched by a user's finger, the detection light beam is diffusely reflected at the fingerprint ridge in contact with the field of view area, and the detection light beam is totally reflected at the point where the field of view area is opposite to the fingerprint valley, wherein at least a portion of the diffusely reflected detection light beam passes through the light guide unit and is received by the detection module, and the detection module converts the received detection light beam into a corresponding electrical signal to obtain fingerprint information.

In some embodiments, the preset area is the field of view area; or, the preset area is located in the field of view area, and the area of the preset area is smaller than the area of the field of view area; or, the field of view area is located in the preset area, and the area of the field of view area is smaller than the area of the preset area; or, part of the preset area overlaps with part of the field of view area; the part of the preset area that does not overlap with the field of view area is defined as a non-overlapping area, and at least part or all of the non-overlapping area is closer to the light source than the overlapping area.

In some embodiments, when there is no user finger touching the field of view area, the detection light beam that can be totally reflected in the field of view area includes the detection light beam that reaches the field of view area after multiple total reflection transmissions from the non-overlapping area, or/and the detection light beam that reaches the overlapping area for the first time after entering the protective layer from the light source and satisfies the total reflection in the overlapping area.

In some embodiments, the second surface is arranged opposite to the first surface, and the area where the light source enters on the second surface is defined as the light entrance area, and the detection light beam enters the interior of the light guide unit from the light entrance area and is transmitted to the preset area; there is a shortest straight line between the light entrance area and the overlapping area, and the angle between the shortest straight line and the normal of the overlapping area is not less than the critical angle of the detection light beam for total reflection transmission in the light guide unit, or the detection light beam with the shortest distance from the light entrance area to the overlapping area meets the condition for total reflection transmission in the light guide unit, or the detection light beam directly projected by the light source to the overlapping area through the second surface meets the condition for total reflection transmission in the light guide unit.

In certain embodiments, the light guiding unit includes an upper surface and a lower surface that are arranged opposite to each other, and the detection module is arranged below the lower surface for receiving a detection light beam emitted from the lower surface, and the first surface is the upper surface; the second surface is the lower surface, or the second surface is a slope or side surface of the light guiding unit, and the slope or side surface is located between the upper surface and the lower surface.

In some embodiments, the light source includes a light emitting unit and a light converter, the light emitting unit is used to emit a non-collimated detection light beam, and the light converter is used to convert the angle of the non-collimated detection light beam entering the light guide unit, so that the detection light beam can directly illuminate the preset area after entering the light guide unit and can be transmitted by total reflection within the light guide unit.

In some embodiments, the light converter is arranged between the light emitting surface of the light emitting unit and the second surface, or the light converter and the light guiding unit are integrally formed, and the light incident area of the detection light beam on the second surface is a partial surface of the light converter.

In some embodiments, the optical detection device also includes a display device, the display device includes a protective layer and a display module, the protective layer includes an upper surface and a lower surface arranged opposite to each other, the display module is arranged on one side of the lower surface of the protective layer for performing image display, and the detection module is used to receive a detection light beam emitted from the light guide unit through at least a portion of the display module; the upper surface of the protective layer is the first surface of the light guide unit.

In certain embodiments, the protective layer includes a transparent area and a non-transparent area located in the transparent area, the display module is used to emit a visible light beam through the transparent area, the light incident area of the light source on the second surface is located in the non-transparent area, and the wavelength of the detection light beam is different from the wavelength of the visible light beam.

In some embodiments, the display device also includes optical glue for connecting the protective layer and the display module, and the light guide unit includes or is the protective layer, or the light guide unit includes or is the protective layer and the optical glue, or the light guide unit includes or is the protective layer, the optical glue, and at least a portion of the display module.

In some embodiments, the protective layer includes a transparent substrate, the refractive index of the optical adhesive is greater than or equal to the refractive index of the transparent substrate, and the refractive index of the transparent substrate is greater than the refractive index of air.

In some embodiments, the area where the display module displays images is defined as a display area, and the area around the display area where images cannot be displayed is defined as a non-display area; the field of view area is located directly above a partial area of the display area.

The beneficial effect of the present invention is that the optical detection device of the present invention includes a light guide unit, a detection module and a light source, the light guide unit includes a first surface and a second surface, the light source is used to provide a detection light beam, the detection light beam enters the light guide unit from the second surface of the light guide unit and can be transmitted by total reflection inside the light guide unit, and the detection light beam is diffusely reflected at the contact point between the first surface and the ridge. The detection module is located on the side of the light guide unit away from the first surface, the detection module can receive the diffusely reflected detection light beam through the light guide unit and convert it into an electrical signal, the electrical signal can be used for fingerprint image generation or fingerprint recognition, and the area where the detection light beam is diffusely reflected is opposite to the detection module. The optical detection device can be used for fingerprint detection, fingerprint optical imaging, fingerprint recognition, etc. under or inside the screen. The optical detection device of the present invention has a good fingerprint detection effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of an optical detection device according to an embodiment of the present invention;

FIG2 is a partial cross-sectional schematic diagram of the optical detection device shown in FIG1 ;

FIG3 is a partial cross-sectional schematic diagram of a modified embodiment of the optical detection device shown in FIG1 ;

FIG4 is a partial cross-sectional schematic diagram of a modified embodiment of the optical detection device shown in FIG1 ;

FIG5 is a schematic diagram of a partial cross section of an optical detection device;

FIG6 is a schematic diagram of a partial cross section of an optical detection device;

7 is a partial cross-sectional schematic diagram of an embodiment of an optical detection device of the present invention;

FIG8 is a partial perspective schematic diagram of the optical detection device shown in FIG7;

FIG9 is a further partial cross-sectional schematic diagram of the optical detection device shown in FIG7 ;

FIG10 is a partial cross-sectional schematic diagram of a modified embodiment of the optical detection device shown in FIG7;

FIG11 is a partial cross-sectional schematic diagram of a modified embodiment of the optical detection device shown in FIG7;

FIG12 is a partial cross-sectional schematic diagram of an embodiment of an optical detection device of the present invention;

FIG. 13 is a partial cross-sectional schematic diagram of an embodiment of an optical detection device of the present invention.

Detailed ways

In the specific description of the embodiments of the present invention, it should be understood that when a substrate, sheet, layer or pattern is referred to as being "on" or "under" another substrate, another sheet, another layer or another pattern, it may be "directly" or "indirectly" on another substrate, another sheet, another layer or another pattern, or one or more intermediate layers may also exist. For the purpose of clarity, the thickness and size of each layer in the drawings of the specification may be exaggerated, omitted or schematically indicated. In addition, the size of the elements in the drawings does not fully reflect the actual size.

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Further, the described features and structures may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided so that the embodiments of the present application can be fully understood. However, those skilled in the art will appreciate that, even without one or more of the specific details, or by adopting other structures, components, etc., the technical scheme of the present application may also be put into practice. In other cases, known structures or operations are not shown or described in detail to avoid blurring the key points of the present application.

Please refer to Figures 1 and 2 simultaneously. Figure 1 is a schematic diagram of an embodiment of an optical detection device 1 of the present invention, and Figure 2 is a partial cross-sectional schematic diagram of the optical detection device 1 along the P-P line in Figure 1. The optical detection device 1 includes a light guide unit 100, a detection module 19, a light source 16, and the light guide unit 100. The detection module 19 is at least partially located below the light guide unit 100. The light source 16 is located below the light guide unit 100.

The light guide unit 100 includes a first surface and a second surface, and the first surface and the second surface are different surfaces of the light guide unit 100. In this embodiment, the first surface is the upper surface of the light guide unit 100, and the second surface is the lower surface of the light guide unit 100, and the upper surface and the lower surface are arranged opposite to each other. Optionally, in other or modified embodiments, the second surface can be an inclined surface or a side surface of the light guide unit 100. Optionally, the first surface is a plane, or the main body of the first surface is a plane, and the edge portion located at the main body is a curved surface. The light source 16 is used to project the detection light beam 101 to at least one preset area P1 of the first surface through the second surface of the light guide unit 100. The detection module 19 has a field of view area V1 on the first surface of the light guide unit 100. The preset area P1 is the area where the detection light beam 101 first reaches the first surface after entering the interior of the light guide unit 100 from the second surface of the light guide unit 100 and being transmitted. The field of view area V1 is the area where the user's finger touches the first surface during fingerprint detection, and is also the part of the first surface that is located in the maximum range of the light beam that can be received by the detection module 19. The first surface of the light guide unit 100 is the surface that the user's finger directly contacts during fingerprint detection, and is usually the outermost surface of the optical detection device 1 or an electronic product including the optical detection device 1. For the convenience of description, the preset area P1 can also be regarded as the area directly irradiated by the detection light beam 101 on the first surface.

Part or all of the detection light beam 101 meets the conditions for total reflection transmission in the light guide unit 100, and when there is no user finger touching the preset area P1, there is a detection light beam 101 that is totally reflected in the field of view area V1. When there is a user finger touching the field of view area V1, the detection light beam 101 is diffusely reflected at the fingerprint ridge 1100 that is in contact with the field of view area V1, and the detection light beam 101 is totally reflected at the point where the field of view area V1 is directly opposite to the fingerprint valley 1200. Among them, at least part of the diffusely reflected detection light beam 101 passes through the light guide unit 100 and is received by the detection module 19, and the detection module 19 converts the received detection light beam 101 into a corresponding electrical signal to obtain fingerprint information.

The detection module 19 is located below the second surface of the light guide unit 100 , and is used to receive the detection light beam 101 emitted from the second surface of the light guide unit 100 , and convert the received detection light beam 101 into a corresponding electrical signal to obtain fingerprint information.

In this embodiment, the preset area P1 is the field of view area V1 of the detection module 19 on the upper surface of the light guide unit 100. In other or modified embodiments, the preset area P1 may be located in the field of view area V1, or the preset area P1 partially overlaps with the field of view area V1, or there is no overlap between the preset area P1 and the field of view area V1. When there is no overlap between the preset area P1 and the field of view area V1, the preset area P1 and the field of view area V1 are spaced apart or adjacent to each other. This is not limited in the embodiment of the present invention.

Optionally, in some embodiments, the optical detection device 1 is applied in an electronic product, and the electronic product includes a midline from its top to its bottom, and the center of the field of view area V1 is located on the midline or close to the midline.

Optionally, in some embodiments, the optical detection device 1 is applied in an electronic product, and the electronic product includes a center line from its top to its bottom, and the center of the preset area P1 is located on the center line or close to the center line.

Optionally, in some embodiments, the optical detection device 1 is used in an electronic product, and the interval between the field of view area V1 and the bottom edge of the electronic product is 3 to 20 mm, or 3 to 15 mm, or 3 to 10 mm. Further optionally, in some embodiments, the light source 16 and the detection module 19 are both arranged adjacent to the bottom edge of the electronic product, the light source 16 is closer to the bottom edge of the electronic product than the detection module 19, and the horizontal distance between the detection module 19 and the light source 16 is 10 to 15 mm.

Optionally, in some embodiments, when the preset area P1 and the field of view area V1 overlap, the overlapping portion of the two is defined as the overlapping area. The detection light beam 101 of the shortest distance from the light incident area 113 to the overlapping area satisfies the condition of total reflection transmission in the light guide unit 100, or the detection light beam 101 directly projected by the light source 16 to the overlapping area through the second surface can be fully reflected and transmitted in the light guide unit 100.

In this embodiment, the second surface of the light guide unit 100 has a light entrance area 113 for the detection beam 101 to enter. The angle between the shortest straight line between the light entrance area 113 and the preset area P1 and the normal line of the upper surface of the light guide unit 100 is not less than the critical angle for the detection beam to achieve total reflection transmission in the light guide unit 100. The light entrance area 113 of the detection beam 101 on the second surface is a plane or a non-plane.

Optionally, in some embodiments, there is a shortest straight line between the light incident area 113 and the overlapping area, and the angle between the shortest straight line and the normal of the overlapping area is not less than the critical angle of the detection light beam for total reflection transmission in the light guide unit 100, or the detection light beam of the shortest distance from the light incident area 113 to the overlapping area satisfies the condition for total reflection transmission in the light guide unit 100, or the detection light beam directly projected by the light source 16 to the overlapping area through the second surface satisfies the condition for total reflection transmission in the light guide unit.

Optionally, in some embodiments, for example but not limited to, the angle between the shortest straight line between the light incident area 113 and the field of view area V1 and the normal of the first surface of the light guiding unit 100 is not less than the critical angle for the detection light beam 101 to achieve total reflection transmission in the light guiding unit 100.

Optionally, in some embodiments, for example but not limited to, the angle between the shortest straight line between the light incident area 113 and the overlapping area of the preset area P1 and the field of view area V1 and the normal of the first surface of the light guiding unit 100 is not less than the critical angle for the detection light beam 101 to achieve total reflection transmission in the light guiding unit 100.

Optionally, in some embodiments, it can be understood that as long as the detection light beam 101 emitted by the light source 16 can reach the light entrance area 113, the light source 16 can be set at any position of the optical detection device 1. For example, but not limited to, the light source 16 can be set below the detection module 19 and transmit the emitted detection light beam 101 to the light entrance area 113 through a light guide element, and the light guide element can be a solid light guide structure, and/or, the light guide element can be a cavity light guide structure. Optionally, in some embodiments, the detection light beam 101 emitted by the light source 16 can directly reach the light entrance area 113 without passing through the light guide element.

In this embodiment, the light source 16 is used to project a detection light beam 101 through the lower surface of the light guide unit 100 to at least one preset area P1 on the upper surface of the light guide unit 100. The detection light beam 101 is a non-collimated light beam. Moreover, part or all of the detection light beam 101 projected to the preset area P1 meets the condition of total reflection transmission in the light guide unit 100. When there is no finger or other detection object in contact with the preset area P1, there is a detection light beam 101 that is totally reflected in the field of view area V1. During fingerprint detection, the ridge 1100 of the finger fingerprint 1000 contacts the field of view area V1, and the valley 1200 has a spacer with the corresponding part of the field of view area V1. The spacer can be air, water, etc. Generally, the spacer between the valley of the fingerprint and the preset area P1 is air. Of course, due to reasons such as finger sweating, the spacer between the valley of the fingerprint and the preset area P1 can be liquid or other. The embodiment of the present invention is described with the spacer being air. It is understandable that other possible spacers also fall within the scope of the present invention, and the embodiment of the present invention does not limit this.

It is understandable that, although for illustrative purposes, the optical detection device 1 is generally described in the context of this application using fingerprints as an example, the optical detection device 1 is not limited to the detection of fingerprints, and the detection object of the optical detection device 1 can be any object to be imaged. Generally, the detection object will have various characteristics including biometrics. It should be noted that, as an example, the optical detection device 1 of the present invention is described using finger fingerprints as the detection object, and it is understandable that the lines of the palm, toes, palm prints, skin surface textures, etc. can also be used as the detection object of the present invention or the characteristics of the external object to be detected.

The fingerprint 1000 has ridges 1100 and valleys 1200. When detecting, the ridges 1100 contact the upper surface of the light guide unit 100 (i.e., the outer surface of the optical detection device 1 for the user to touch). In contrast, the valleys 1200 do not contact the upper surface of the light guide unit 100, and there is a spacer between the valleys 1200 and the upper surface. It can be understood that the fingerprint 1000 may have substances such as stains, ink, and moisture, and the embodiments of the present invention are also applicable to the optical imaging of the fingerprint 1000 having these substances.

The detection beam 101 is diffusely reflected at the ridge 1100 of the fingerprint 1000. The detection module 19 can receive the detection beam 101 returned from the ridge 1100 through the light guide unit 100. The detection module 19 receives the detection beam 101 and converts it into an electrical signal. The electrical signal can be used for optical imaging or fingerprint detection of the fingerprint 1000. The detection beam 101 irradiated at the field of view area V1 opposite to the valley is totally reflected.

In this embodiment, the preset area P1 is the field of view area V1 of the detection module 19 on the upper surface of the light guide unit 100. Optionally, in other or modified embodiments, the preset area P1 may be a part of the field of view area V1, which may be located in the field of view area V1. Optionally, in other or modified embodiments, the preset area P1 may overlap with the field of view area V1 or may not overlap. It should be noted that the overlap between the field of view area V1 and the preset area P1 described in the present application includes: the field of view area V1 and the preset area P1 completely overlap, the field of view area V1 is a part of the preset area P1, the preset area P1 is a part of the field of view area V1, or the preset area P1 and the field of view area V1 have a common partial area.

It should be noted that the attached drawings of the present invention are only exemplary representations. In fact, the size of the ridges and valleys of fingerprints is very small (about 300 to 500 microns). The fingerprint range that needs to be detected during fingerprint detection is about 4 mm*4 mm to 10 mm*10 mm, or a larger area.

The lower surface of part of the light guide unit 100 has a light entrance area 113, and the detection light beam 101 emitted by the light source 16 enters the light guide unit 100 through the light entrance area 113. At least part of the detection light beam 101 entering the light guide unit 100 from the light entrance area 113 directly irradiates and covers the preset area P1. In this embodiment, the detection light beam 101 irradiating the preset area P1 all meets the condition of total reflection transmission in the light guide unit 100.

It should be noted that, although the light entrance area 113 described in the present embodiment is located on the lower surface of the light guide unit 100, the present invention is not limited to this, and the light entrance area 113 may be located at other positions of the light guide unit 113. For example, but not limited to, the light entrance area 113 may be located on a side surface of the light guide unit 100, and the side surface of the light guide unit 100 may be connected to its upper surface and lower surface. Alternatively, the light entrance area 113 may be located on an inclined surface of the light guide unit 100, and the inclined surface of the light guide unit 100 may be an edge portion of the light guide unit 100 with a certain inclination angle relative to its upper surface or lower surface. Therefore, the light entrance area 113 may be located at any suitable position of the light guide unit 100, and the present invention is not limited to this.

Optionally, in other or modified embodiments, the portion of the detection light beam 101 that is directly irradiated to the preset area P1 satisfies the condition of total reflection transmission within the light guiding unit 100, for example but not limited to, another portion of the detection light beam 101 is refracted and/or reflected on the preset area P1.

Further optionally, no less than 20%-30% of the detection light beam 101 irradiated to the preset area P1 meets the condition of total reflection transmission in the light guide unit 100. At this time, for example but not limited to, the total power of the light source 16 can be 90mW (milliwatt) ~ 120mW, when the light source includes 3 light-emitting elements, each light-emitting element power can be 30mA (milliampere) ~ 40mA, and the current can be 70mA. Of course, the proportion of the detection light beam 101 that meets the condition of total reflection transmission irradiated to the preset area P1 can be greater than 30%, 40%, 50%, at which time the current or power of the light source 16 can be appropriately adjusted accordingly, so as to reduce energy consumption and heat generation. When the proportion of the detection light beam 101 that meets the condition of total reflection transmission irradiated to the preset area P1 is less than 20% or 10%, the current or power of the light source 16 needs to be increased accordingly to meet the light intensity required for fingerprint optical imaging.

Optionally, in other or modified embodiments, part or all of the detection light beam 101 entering the light guide unit 100 from the light entrance area 113 satisfies the condition of total reflection transmission in the light guide unit 100. The condition of total reflection transmission includes: the detection light beam 101 is totally reflected at the first surface of the light guide unit 100 that does not contact the ridge of the fingerprint, and is totally reflected on the second surface of the light guide unit 100. The detection light beam 101 is diffusely reflected at the contact point between the first surface of the light guide unit 100 and the ridge 1100 of the fingerprint 1000.

Optionally, in some embodiments, when the first surface and the second surface are not arranged opposite to each other, for example but not limited to, the first surface is the upper surface of the light guide unit 100, and the second surface is the side surface of the light guide unit 100, then the light guide unit 100 further includes a third surface opposite to the first surface. The detection light beam 101 enters the light guide unit 100 from the second surface, and can be totally reflected on the first surface and the third surface, and then totally reflected and transmitted in the light guide unit 100.

In this embodiment, the detection beam 101 entering the light guide unit 100 is a non-collimated beam or a non-parallel beam. The non-collimated detection beam 101 includes a plurality of detection rays, and the angle between at least two detection rays is not less than 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

In this embodiment, the detection beam 101 is invisible light, including but not limited to near infrared light. The near infrared light is, for example, a beam with a wavelength range of 750 to 2000 nm (nanometers). For example, but not limited to, the detection beam 101 is near infrared light with a wavelength of 800 to 1200 nm.

Exemplarily, the light guide unit 100 may include a transparent material, such as but not limited to transparent glass, transparent polymer material, any other transparent material, etc. The light guide unit 100 may be a single-layer structure or a multi-layer structure.

It should be noted that the detection module 19 in this embodiment receives the detection beam 101 diffusely reflected at the ridge 1100 and is used for fingerprint optical imaging. However, the present invention is not limited to this, and the detection module 19 can receive other light beams with fingerprint feature information for imaging or detection. For example, but not limited to, the detection module 19 can receive the detection beam 101 directly reflected from the surface of the user's finger (including the ridges and/or valleys of the fingerprint) and use it for fingerprint detection; for example, but not limited to, the detection module 19 can receive the visible light and/or invisible light in the external environment reflected by the user's finger and use it for fingerprint detection; for example, but not limited to, the detection module 19 can receive the visible light and/or invisible light in the external environment transmitted by the user's finger and use it for fingerprint detection; for example, but not limited to, the detection module 19 can receive the visible light and/or invisible light emitted by the user's finger and use it for fingerprint detection. Further, the above-mentioned fingerprint detection can also be detection of other detection objects, and any detection object that can obtain feature information of the detection object by optical imaging is acceptable. Therefore, although the embodiment of the present invention is described by taking the receiving of diffusely reflected detection light beam 101 as an example, other possible light beams used for fingerprint optical imaging also fall within the protection scope of the present invention.

Please refer to FIG. 3 , the optical detection device 1A is a modified embodiment of the optical detection device 1 , and the structure of the optical detection device 1A is basically the same as that of the optical detection device 1 . For the convenience of description, the component numbers of FIG. 3 and FIG. 2 are consistent. The difference is that the preset area P1 of the optical detection device 1A partially overlaps with the field of view area V1 , as shown in FIG. 3 , the overlapping area is represented by Q1 , and the preset area P1 includes the overlapping area Q1 and the irradiation area of the light source 16 that is closer to the overlapping area Q1 . The area of the overlapping area Q1 is greater than or equal to 30% of the area of the field of view area V1 and less than or equal to 100% of the area of the field of view area V1 . For example, but not limited to, the area of the overlapping area Q1 accounts for 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 90%, 95%, 100% of the area of the field of view area V1 .

When there is no user finger touching the field of view area V1, the detection light beam 101 that can be totally reflected on the field of view area V1 includes a detection light beam that is transmitted from a non-overlapping area (the area where the preset area P1 does not overlap with the field of view area V1 is a non-overlapping area) through multiple total reflections to reach the field of view area V1, or/and, a detection light beam 101 that enters the light guide unit 100 from the light source 16 and reaches the overlapping area Q1 for the first time and satisfies total reflection in the overlapping area Q1.

There is a shortest straight line between the light incident area and the overlapping area Q1, and the angle between the shortest straight line and the normal of the overlapping area is not less than the critical angle of the detection light beam for total reflection transmission in the light guiding unit, or the detection light beam of the shortest distance from the light incident area to the overlapping area Q1 satisfies the condition for total reflection transmission in the light guiding unit 100, or the detection light beam directly projected by the light source 16 to the overlapping area Q1 through the second surface satisfies the condition for total reflection transmission in the light guiding unit 100.

Part or all of the detection light beam 101 irradiated on the preset area P1 outside the overlapping area Q1 can reach the field of view area V1 (including the overlapping area Q1 of the field of view area V1 and the preset area P1 and the area where the field of view area V1 does not overlap with the preset area P1) after total reflection transmission. When the user's finger touches the field of view area V1: the detection light beam 101 that enters from the light incident area 113 and first reaches the overlapping area Q1 is diffusely reflected at the ridge 1100 of the fingerprint and is totally reflected at the relative valley 1200 of the overlapping area Q1; the detection light beam 101 that is transmitted to the field of view area V1 by total reflection from the part outside the overlapping area of the preset area P1 is also diffusely reflected at the ridge 1100 of the fingerprint and is totally reflected at the relative valley 1200 of the overlapping area Q1. The detection module 19 receives the diffusely reflected detection light beam 101 on the side of the light guide unit 100 away from the first surface and uses it for fingerprint imaging. The first surface is the outermost surface of the light detection device 1 , and the detection module 19 is located on a side of the light guide unit 100 facing away from the outer side.

Please refer to FIG. 4 . The optical detection device 1B is a modified embodiment of the optical detection device 1 . The structure of the optical detection device 1B is basically the same as that of the optical detection device 1 . For the convenience of description, the component numbers of FIG. 4 and FIG. 2 are consistent. The difference is that there is no overlap between the preset area P1 and the field of view area V1 of the optical detection device 1A, and part or all of the detection light beam 101 irradiated on the preset area P1 can be transmitted to the field of view area V1 by total reflection. When the user's finger touches the field of view area V1: the detection light beam 101 irradiated on the preset area P1 can be transmitted to the field of view area V1 by total reflection, and the field of view area V1 is the area for the user's finger to touch. The detection light beam 101 is diffusely reflected at the ridge 1100 of the fingerprint and is totally reflected at the valley 1200 relative to the overlap area. The detection module 19 receives the diffusely reflected detection light beam 101 on the side of the light guide unit 100 away from the first surface and uses it for fingerprint imaging. The first surface of the light guide unit 100 is the surface touched by the user. By projecting the detection beam 101 into the light guide unit 100, the detection beam 101 can directly illuminate the field of view area V1, or the detection beam 101 is transmitted to the field of view area V1 by total reflection. During fingerprint detection, the user's finger touches the field of view area V1, and the detection beam 101 is diffusely reflected at the ridge 1100 of the fingerprint. The detection module 19 is arranged below the light guide unit 100 opposite to the field of view area V1. The detection module 19 receives the detection beam 101 that passes through the light guide unit 100 after diffuse reflection and converts it into an electrical signal. The area of the vertical projection of the detection module 19 on the first surface is smaller than the area of the field of view area V1, or the vertical projection of the detection module 19 on the first surface is located within the field of view area V1. The optical detection device 1 collects the diffusely reflected detection beam 101 for imaging, thereby realizing fingerprint detection and identification. The diffusely reflected detection light beam 101 can enter the detection module 19 at different incident angles, and the volume of the detection module 19 is relatively small.

Of course, in some embodiments, collimated light can also be used as the detection beam. It can be understood that if a collimated light beam is used as the detection beam, the width of the preset area will be the same as the width of the light-entering area. Since the mainstream electronic products that can display images are now pursuing full screens and narrow borders, the area of the optical detection device 1 used to display images can be called a visible area, and the part around the visible area that does not display images is called a border area. The border area is narrow, and in order not to affect the image display in the visible area, the light-entering area 113 is generally located in the border area of the optical detection device 1, so the width of the light-entering area 113 is also very small. Correspondingly, the width of the preset area P1 will also be very small, and the field of view area V1 is generally a rectangle of 5 mm * 5 mm or a circular area with a radius of 2 to 5 mm. Due to the parallel transmission characteristics of collimated light, at this time, the following problems are likely to occur: there are certain positions on the field of view area V5 where no detection beam can be directly irradiated, and no detection beam can reach these positions of the field of view area V5 after total reflection. As shown in FIG5 , there are some areas in the field of view area V5 that are not illuminated by the detection beam, resulting in that some fingerprints corresponding to these positions cannot be detected. Therefore, although the detection beam of collimated light can also detect fingerprints or perform optical imaging, it has a major disadvantage, and the detection efficiency and imaging quality of fingerprints are not as good as the detection beam 101 of non-collimated light.

Of course, in some other embodiments, a non-collimated detection light beam 101 may also be used. Please refer to FIG. 6 . The non-collimated detection light beam 101 passes through the optical light guide unit 100 after total reflection and can be further received by a detection module. At this time, it is equivalent to the optical detection device 1 receiving the totally reflected detection light beam 101 for imaging and detection. For example, the non-collimated detection light beam 101 passes through the light guide unit 100 of the optical detection device 1 after total reflection on the upper surface of the light guide unit 100 and is further received by the detection module. During fingerprint detection, the user's finger touches the upper surface of the light guide unit 100 and is directly irradiated by the detection light beam 101. The detection light beam 101 irradiated at the ridge 1100 is diffusely reflected and will not be received by the detection module or the light intensity of this part of the detection light beam received by the detection module is less than the incident light. The detection light beam 101 irradiated to other positions is totally reflected and emitted through an optical element attached to the lower surface of the light guide unit 100. The light intensity of this part of the total reflection received by the detection module is the same as the incident light, thereby obtaining an image of the fingerprint with light and dark contrast. However, in these embodiments, it is necessary to set an optical element on the lower surface of the light guide unit 100 so that the detection light beam 101 can be emitted from the lower surface after being totally reflected on the upper surface of the light guide unit 100. The provision of the optical element will inevitably lead to an increase in the cost and assembly complexity of the optical detection device 1. Moreover, in these embodiments, since the detection light beam 101 is non-collimated light, it has a certain divergence angle when projected on the preset area P1 on the upper surface of the light guide unit 100, so the width of the preset area P1 is greater than the width of the light incident area 113. Correspondingly, the reflected light of the detection light beam 101 after total reflection in the preset area 15 also has a certain divergence angle. Therefore, it can be understood that the detection light beam 101 that is totally reflected to the lower surface of the light guide unit is emitted from the lower surface, and the width of the emission area corresponding to the emission light beam 101 on the lower surface is greater than the width of the preset area P1. Therefore, the fingerprint image formed by the detection light beam 101 that is totally reflected to the lower surface and emitted will show a relatively serious magnification phenomenon, thereby causing the fingerprint image to deform. In addition, the emission area of the detection light beam 101 on the lower surface of the light guide unit 100 is relatively large. Accordingly, the detection module for receiving the emitted detection light beam 101 requires a larger volume and area to receive the detection light beam 101 from the emission area. For example, but not limited to, the detection module requires a larger photosensitive area, or a larger lens, etc. For example, the detection module needs to be equipped with a relatively large lens, and the cross-sectional area of the lens needs to be no less than the area of the preset area P1; or the detection module needs to be equipped with a relatively large image sensor, and the area of the photosensitive area of the image sensor receiving the detection beam 101 needs to be no less than the area of the preset area P5. In this way, in order to set up the detection module, it is even necessary to occupy the original space of other components, which will affect the overall volume, cost and assembly of the optical detection device 1, and it is not suitable for the needs of being set inside electronic products such as mobile phones.

Furthermore, according to the total reflection optical principle, the horizontal distance between the total reflected detection light beam 101 and the light source 16 in the exit area of the lower surface of the light guide unit is greater than the horizontal distance between the preset area P1 and the light source 16. Moreover, the exit direction of the detection light beam 101 emitted from the exit area follows the principle of reflection and refraction, so the detection module that receives these detection light beams 101 needs to be set on the corresponding exit light path to ensure the reception and imaging effect. Therefore, the horizontal distance between the detection module and the light source 16 is greater than the horizontal distance between the preset area P1 and the light source 16. The detection module needs to be located on the side of the preset area P5 away from the light source 56, and the detection light beam 101 needs to be transmitted in a longer path inside the light guide unit to be emitted, and needs to be transmitted in the part outside the preset area P1 of the light guide unit. In this case, if the light guide unit between the preset area P1 and the above-mentioned exit area is broken or damaged, the detection light beam 101 will not be able to smoothly exit from the exit area of the lower surface of the light guide unit through total reflection. In other words, when the area outside the preset area P1 of the light guide unit is damaged, it will affect the reception and imaging of the detection light beam, resulting in a decrease in user experience.

Please refer to FIG. 7 , which is a partial cross-sectional schematic diagram of an embodiment of the present invention. The optical detection device 3 includes a protective layer 300, a display module 31, a light source 36 and a detection module 39. The protective layer 300 and the display module 31 together constitute a display device. The display module 31 is located below the protective layer 300, and the display module 31 is used to emit a visible light beam through the protective layer 300 to realize image display. The light source 36 is located below the protective layer 300, and the light source 36 is used to emit a detection light beam 301, and the detection light beam 301 includes or is a non-collimated light beam. The detection light beam 301 is incident from the lower surface of the protective layer 300 into the protective layer 300, and the area where the detection light beam 301 first reaches the upper surface of the protective layer 300 after transmission is the preset area P3. The preset area P3 is the direct irradiation area of the detection light beam 301 on the upper surface of the protective layer 300. The detection module 39 has a field of view area V3 on the upper surface of the protective layer 300, and the field of view area V3 is the portion of the upper surface of the protective layer 300 located within the maximum range that the detection module 39 can receive the detection light beam 301. When performing fingerprint detection, the field of view area V3 is an area for the user's finger to touch. The detection module 39 is located below the protective layer 300 or at least part of the detection module 39 is located below the display module 31. Of course, in other or modified embodiments, for example but not limited to, during fingerprint detection, a light source can usually emit visible light at the position of the field of view area V3 on the upper surface of the protective layer 300 to prompt the user to touch the finger at this position. Under the premise of satisfying fingerprint imaging, the area on the upper surface of the protective layer 300 for the user's finger to touch can overlap with the field of view area V3, or the touched area includes the field of view area V3, etc., and the present invention does not limit this. Those skilled in the art can understand that as long as the field of view area V3 or at least part of it is an area touched by a finger, it belongs to the protection scope of the present invention.

In this embodiment, the protective layer 300 is a light-guiding unit of the optical detection device 3, which includes an upper surface 311 and a lower surface 312 relative to each other. The protective layer 300 has a connected non-transparent area 310 and a transparent area 320. The non-transparent area 310 is located around or at the edge of the transparent area 320. The transparent area 320 is used to pass a visible light beam. The non-transparent area 310 is used to block visible light. The visible light beam emitted by the display module 31 is emitted to the outside of the optical detection device 3 through the transparent area 320 to realize image display. The non-transparent area 310 is used to block the visible light beam emitted by the display module 31 and the visible light beam in the ambient light, so that the user cannot see the components inside the optical detection device 3 in the non-transparent area 310.

Typically, the area where the display module 31 displays an image is defined as a display area (not marked), and the area around the display area where the image cannot be displayed is a non-display area (not marked). The transparent area 320 is opposite to the display area, and the vertical projection of the transparent area 320 in the display area is located in the display area or completely overlaps with the display area. The non-transparent area 310 covers the non-display area and exceeds the non-display area in a direction away from the display area. That is, the area of the non-transparent area 310 is larger than the area of the non-display area. When a user uses the optical detection device 3, the display area that the user can actually see on the front of the optical detection device 3 is the same size as the transparent area 320.

Optionally, in some embodiments, the field of view region V3 is located directly above the local area of the display area. Further optionally, the detection module 39 includes an image sensor and an ultra-macro lens located above the image sensor, wherein the ultra-macro lens is used to converge the detection beam 301 onto the image sensor, and the image sensor is used to convert the detection beam 301 into a corresponding electrical signal, and the vertical projection of the ultra-macro lens and the image sensor on the upper surface 311 is located within the field of view region V3, and the area of the vertical projection is smaller than the area of the field of view region V3.

The non-transparent region 310 includes an upper surface (not labeled) and a lower surface (not labeled) disposed oppositely. The transparent region 320 includes an upper surface (not labeled) and a lower surface (not labeled) disposed oppositely. The upper surface 311 of the protective layer 300 includes the upper surface of the non-transparent region 310 and the upper surface of the transparent region 320. The lower surface 312 of the protective layer 300 includes the lower surface of the non-transparent region 310 and the lower surface of the transparent region 320.

The non-transparent area 310 is used to transmit the detection light beam 301 and block the visible light beam. In an embodiment of the present application, the transmittance of the non-transparent area 310 to the detection light beam 301 is greater than a preset value. The preset value is 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%. When the transmittance of the non-transparent area 310 to the detection light beam 301 is greater, the intensity of the detection light beam 301 after penetrating the protective layer 300 is greater.

In addition, the non-transparent area 310 shielding the visible light beam means that the transmittance of the non-transparent area 310 to the visible light beam is less than 10%, 5%, or 1%, or even the transmittance of the non-transparent area 310 to the visible light beam is 0. The smaller the transmittance of the non-transparent area 310 to the visible light beam is, the more the non-transparent area 310 shields the visible light beam. Of course, the transmittance of the non-transparent area 310 to the visible light beam is not limited to less than 10%, as long as the internal components cannot be seen from the outside of the protective layer 300 through the non-transparent area 310.

The non-transparent area 310 blocks the visible light beam by, for example but not limited to, absorbing and/or reflecting the visible light beam.

The display module 31 is located below the transparent area 320 , the light source 36 is located below the non-transparent area 310 , and the detection module 39 is located below the display module 31 .

At least a portion of the light source 36 is in close contact with the lower surface of the non-transparent area 310. The lower surface of the non-transparent area 310 has a light entrance area 313, and the detection beam 301 enters the protective layer 300 from the light entrance area 313. At least a portion of the detection beam 301 entering the protective layer 300 can directly illuminate and cover the preset area P3.

In this embodiment, the preset area P3 and the field of view area V3 of the detection module 39 on the upper surface of the protective layer 300 have an overlapping area Q3. Optionally, in some embodiments, the preset area P3 is the field of view area V3. Optionally, in some embodiments, the preset area P3 and the field of view area V3 are at least partially overlapped, and the overlapping portion of the preset area P3 and the field of view area is defined as the overlapping area, and the portion of the preset area V3 other than the overlapping area is defined as the non-overlapping area. Further optionally, the overlapping area can be the field of view area V3, in which case the field of view area V3 is a part of the preset area P3.

In this embodiment, the detection light beam 301 enters the protective layer 300 from the light incident area 313 and irradiates the preset area P3. Wherein: the detection light beam 301 irradiated to the overlapping area Q3 meets the conditions of total reflection transmission and can be diffusely reflected at the ridge 1100 (when the finger touches the field of view area V3); at least part of the detection light beam 301 irradiated to the non-overlapping area meets the conditions of total reflection transmission, or the detection light beam 301 irradiated to the non-overlapping area does not meet the conditions of total reflection transmission. When at least part of the detection light beam 301 irradiated to the non-overlapping area meets the conditions of total reflection transmission, at least part of the detection light beam 301 irradiated to the non-overlapping area and meeting the conditions of total reflection transmission can reach the field of view area V3 after multiple total reflections, and can be diffusely reflected at the ridge 1100 (when the finger touches the field of view area V3), and then can pass through the protective layer 300 and be received by the detection module 39 located below the protective layer 300.

In this embodiment, the preset area P3 and/or the field of view area V3 are located on the upper surface of the transparent area 320. Optionally, in other or modified embodiments, at least part of the preset area P3 and/or the field of view area V3 is located on the upper surface of the transparent area 320. Optionally, in other or modified embodiments, at least part of the preset area P3 and/or the field of view area V3 is located on the upper surface of the non-transparent area 310.

In this embodiment, the preset area P3 and the field of view area V3 are partial areas of the upper surface of the protective layer 300. For example, but not limited to, the field of view area V3 is a 5 mm*5 mm area of the upper surface of the protective layer 300 adjacent to the middle of its bottom. The preset area P3 and the field of view area V3 are at least partially overlapped. Part or all of the detection light beam 301 directly irradiated to the preset area P3 meets the condition of total reflection transmission in the protective layer 300, that is, meets the condition of total reflection in the light guide unit of the optical detection device 3.

The conditions for the total reflection transmission include: the detection light beam 301 is totally reflected at the upper surface 311 where it does not contact the ridges of the fingerprint, and is totally reflected on the lower surface 312 .

The detection light beam 301 is diffusely reflected at the contact point between the upper surface 311 and the ridge of the fingerprint, and the detection light beam 301 after diffuse reflection is irradiated in all directions.

Optionally, in some embodiments, all the detection light beams 301 entering the protective layer 300 from the light incident area 313 can be fully reflected and transmitted within the protective layer 300 , that is, the detection light beam 310 irradiated to the preset area P3 meets the condition of total reflection transmission.

Optionally, in some embodiments, at least part of the detection light beam 301 entering the protective layer 300 from the light incident area 313 can be fully reflected and transmitted in the protective layer 300, that is, part or all of the detection light beam 301 irradiated to the preset area P3 meets the condition of full reflection transmission. Among them, the detection light beam 301 directly irradiated to the overlapping area of the field of view area V3 and the preset area P3 all meets the condition of full reflection transmission. The overlapping area can be a partial area of the field of view area V3, or the overlapping area is the field of view area V3.

Optionally, in some embodiments, a portion of the detection light beam 301 entering the protective layer 300 directly irradiates the overlapping area of the field of view region V3 and the preset area P3, and a portion of the detection light beam 301 irradiates the non-overlapping area where the preset area P3 and the field of view region V3 do not overlap. At least a portion of the detection light beam 301 irradiated to the non-overlapping area satisfies the condition of total reflection transmission in the protective layer 300, and this portion of the detection light beam 301 can be incident on the field of view region V3 after total reflection in the protective layer 300, and then diffusely reflected at the contact point between the field of view region V3 and the ridge 1100, and then can be received by the detection module 39 after passing through the lower surface of the protective layer 300.

Optionally, in other embodiments, a local area of the preset area P3 overlaps with the field of view area V3 to form an overlapping area. The overlapping area may be a local area of the field of view area V3, or the overlapping area may be the field of view area V3. The area where the preset area P3 does not overlap with the field of view area V3 is defined as a non-overlapping area. The non-overlapping area has a portion closer to the light source 36 than the field of view area V3. It can be understood that, for example but not limited to, the distance between the portion of the non-overlapping area closer to the light source 36 than the field of view area V3 and the light source is not greater than the distance between the field of view area V3 and the light source 36. The area ratio of the portion of the non-overlapping area closer to the light source 36 than the field of view area V3 to the preset area P3 satisfies: not less than 30% and less than 100%. The area ratio of the corresponding overlapping area to the field of view area V3 satisfies: not less than 30% and less than or equal to 100%. At this time, when the area ratio of the non-overlapping area closer to the light source 36 than the field of view area V3 to the area ratio of the preset area P3 increases, more detection light beams 301 irradiated to the non-overlapping area closer to the light source 36 than the field of view area V3 are transmitted to the field of view area V3 through total reflection. Please also refer to Figure 8, which is a partial three-dimensional exploded schematic diagram of the optical detection device 3. There is a point a in the light incident area 313, and a point b in the overlapping area Q3. The straight line ab is the shortest straight line between the light incident area 313 and the overlapping area Q3. The angle A1 between the connecting line ab and the normal of the upper surface 311 is not less than the preset threshold. For example, but not limited to, the preset threshold is the critical angle of total reflection of the detection light beam 301 when the overlapping area Q3 contacts the air.

Optionally, in some embodiments, the refractive index of the protective layer 300 is n1, the refractive index of air is n0, and the preset threshold is arcsin (n0/n1). At this time, the angle between the normal of the detection light beam 301 projected onto the overlapping area Q3 and the overlapping area Q3 is greater than or equal to A1. When the upper and lower surfaces of the transparent area 320 of the protective layer 300 are in contact with air, the detection light beam 301 can be transmitted by total reflection in the transparent area 320 of the protective layer 300.

When the user's finger touches the field of view area V3, part of the detection light beam 301 is diffusely reflected at the ridge 1100 of the finger fingerprint. This part of the detection light beam 301 is no longer transmitted by total reflection. At least a part of the diffusely reflected detection light beam 301 can pass through the lower surface 312 located in the transparent area 320 and reach the detection module 39.

It can be understood that in this embodiment, there is an overlapping area Q3 between the preset area P3 and the field of view area V3, so the detection light beam 301 directly irradiating the overlapping area Q3 from the light incident area 313 also satisfies the condition of total reflection transmission in the light guide unit, and total reflection occurs at the contact point between the overlapping area 13 and the ridge 1100 of the fingerprint 1000. The detection light beam 301 irradiated on the non-overlapping area of the preset area P3 that does not overlap with the field of view area V3 may be refracted, reflected, or totally reflected in the non-overlapping area. This embodiment assumes that at least part of the detection light beam 301 irradiated on the non-overlapping area of the preset area P3 can be totally reflected and transmitted in the light guide unit. Then, for the partial area of the field of view area V3 except the overlapping area Q3, at least part of the detection light beam 301 that directly irradiates the non-overlapping area of the preset area P3 that does not overlap with the field of view area V3 can be irradiated to the field of view area V3 after multiple total reflections, for example but not limited to, can be irradiated to the overlapping area Q3 and/or the part of the field of view area V3 that does not overlap with the preset area P3 after multiple total reflections. In addition, at least part of the detection light beam 301 that directly irradiates the overlapping area Q3 may also be irradiated to the part of the field of view area V3 that does not overlap with the preset area P3 after multiple total reflections. These detection light beams 301 that irradiate the field of view area V3 after multiple total reflections can be diffusely reflected at the contact point between the field of view area V3 and the ridge 1100, and at least part of this diffusely reflected part of the detection light beam 301 may also be received by the detection module 39 and used for imaging the fingerprint 1000.

Exemplarily, the protective layer 300 is, for example but not limited to, transparent glass, whose refractive index is n1=1.5. The refractive index of air is n0=1.0. The preset threshold is 42 degrees. Optionally, considering material and assembly errors, in some embodiments, the preset threshold is 42 degrees ± 3 degrees. Of course, in other or modified embodiments, when the materials are different, the refractive index of different materials is different, and the preset threshold may also change accordingly, all of which belong to the protection scope of the present invention. The embodiments of the present invention are not limited to this.

It can be understood that since the shortest right angle between the light incident area 313 and the field of view area V3 and the angle between the normal of the field of view area V3 is not less than the preset threshold, the detection light beam 301 directly irradiating the field of view area V3 meets the condition of total reflection transmission.

Optionally, in some embodiments, the preset area P3 is the area directly irradiated by the detection light beam 301 on the upper surface of the light guide unit, and when the preset area P3 and the field of view area V3 have an overlapping area, the overlapping area is the area of the field of view area V3 directly irradiated by the detection light beam 301. The angle between the shortest straight line between the light incident area 313 and the overlapping area and the normal of the upper surface of the light guide unit is not less than a preset threshold value, and the preset threshold value satisfies the condition that the detection light beam 301 is fully reflected and transmitted inside the light guide unit.

In this embodiment, the refractive index of the protective layer 300 is greater than the refractive index of air. Optionally, in some embodiments, the protective layer 300 may be a protective layer made of a transparent material, and the upper surface 311 of the protective layer 300 is the surface that the user's finger directly contacts when using the optical detection device 1. The upper surface 311 of the protective layer 300 includes the upper surface of the transparent area and the upper surface of the non-transparent area. The non-transparent area 310 and the transparent area 320 are integrally formed. Optionally, in other or modified embodiments, at least part of the non-transparent area 310 and the transparent area 320 are integrally formed, or the non-transparent area 310 and the transparent area 320 are assembled. Optionally, in some embodiments, the protective layer 300 is, for example but not limited to, a protective layer comprising materials such as glass or sapphire.

During fingerprint detection, including but not limited to, when the optical detection device 1 is unlocked or payment is made through the optical detection device 1, the user's finger touches the field of view area V3. The area in contact with the ridge 1100 of the fingerprint 1000 on the field of view area V3 is defined as the ridge area, and the area opposite to the valley 1200 of the fingerprint 1000 through the spacer is defined as the valley area. The detection light beam 301 that is directly or indirectly irradiated to the ridge area after total reflection is diffusely reflected, and at least part of the diffusely reflected detection light beam 301 passes through the lower surface 322 of the transparent area 320 and the display module 31 to reach the detection module 39. The detection module 39 receives the detection light beam 301 and converts it into a corresponding electrical signal, which can be used to form an image of the fingerprint 1000 or to represent the characteristics of the fingerprint 1000, for example but not limited to.

The detection light beam 301 irradiated to the valley area directly or indirectly after total reflection is totally reflected. Since the valley area is opposite to the valley 1200 through the spacer, in this embodiment, the spacer is described as air, and those skilled in the art can understand that the spacer can be water, liquid, sweat, or other objects.

Optionally, in other or modified embodiments, during fingerprint detection, some areas of the preset area P3 do not contact the ridge 1100, nor are they opposite to the valley 1200. These areas are areas not covered by the fingerprint, and the areas on the preset area P3 that are not covered by the fingerprint 1000 are defined as empty areas. The detection light beam 301 directly irradiated on the empty area is totally reflected.

Optionally, the optical detection device 3 further includes a bracket, and the light source 36 can be fixedly connected or detachably connected to the bracket by means of glue, double-sided tape, adhesive, bolts, brackets, buckles, slots, welding, etc. Further optionally, the bracket can be any component for fixedly connecting to the protective layer 300 and/or the display module 31, such as but not limited to a middle frame fixedly connected to the protective layer 300, the display module 31 can be accommodated in the middle frame, and the light source 36 is connected to the inner side wall or bottom of the middle frame.

Optionally, the detection module 39 can be fixedly connected or detachably connected to a bracket by means of glue, double-sided tape, adhesive, bolts, brackets, buckles, slots, welding, etc.

In this embodiment, the display module 31 can be, for example, but not limited to, a liquid crystal display module, an electronic paper display module, a micro display projector module, etc. The display module 31 may include a display unit (not shown) located below the protective layer 300 and a backlight unit (not shown) located below the display unit. The backlight unit is used to provide a backlight beam of visible light to the display unit, and the display unit is used to display an image under the illumination of the backlight beam. The display unit and the backlight unit can transmit the detection beam emitted from the lower surface of the light guide unit after diffuse reflection at the finger ridge in the preset area.

Optionally, the detection module 39 is at least partially located below the backlight unit; or the detection module is located inside the display unit, or the detection module is located inside the backlight unit, or the detection unit is located between the display unit and the backlight unit.

Optionally, in other or modified embodiments, the display module 31 includes two opposing substrates and a display layer located between the substrates, and the display layer may be an organic light emitting diode (OLED) layer or a liquid crystal layer. It should be noted that the present invention is not limited to the above, and the display module 31 may be other appropriate display modules, display components or displays. Optionally, in some embodiments, the display module 31 may be a self-luminous display device, and the display module 31 and the protective layer 300 together constitute a self-luminous display device.

Please further refer to FIG. 9 . In this embodiment, the light source 36 includes a light emitting unit 361 and a light converter 362 . The light emitting unit 361 emits a non-collimated detection light beam 301 . The light converter 362 is used to convert the angle at which the detection light beam 301 emitted by the light emitting unit 361 enters the protective layer 300 , so that at least a portion of the detection light beam 301 can directly irradiate the preset area P3 after entering the protective layer 300 and meet the condition of total reflection transmission in the protective layer 300 , that is, meet the condition of total reflection in the light guide unit of the optical detection device 3 . For example, but not limited to, when the detection light beam 301 enters the protective layer 300 through the light converter 362 , the angle of the normal line of the preset area P3 satisfies the preset condition, so that the detection light beam 301 can be fully reflected and transmitted inside the protective layer 300 . The light converter 362 is located close to the lower surface of the non-display area 310 . The light output surface of the light converter 362 for emitting the detection light beam 301 at least covers the light input area 313 . In this embodiment or other modified embodiments, the light converter 362 is the light converter including one or more of an optical film, a grating, an aperture, an optical microstructure, a diffractive optical element, a lens, a prism, a prismatic structure, a spherical table structure, a semi-cylindrical structure or other optical structures, or a combination of the above.

Optionally, in some embodiments, the light converter 362 may also be omitted or integrated into the protective layer 300 , and the light emitting unit 361 directly emits the detection light beam 301 into the protective layer 300 or the light guiding unit.

Optionally, in some embodiments, the incident angle of the detection beam 301 relative to the preset area P3 when entering the protective layer 300 is not less than the critical angle of total reflection when the upper surface of the protective layer 300 contacts the air. For example, but not limited to, the incident angle is not less than 42 degrees.

Optionally, in some embodiments, the light converter 362 is arranged between the light emitting surface of the light emitting unit 361 and the lower surface of the protective layer 300, or the light converter 362 and the protective layer 300 are integrally formed, and the light incident area 313 is a partial surface of the light converter 362.

Optionally, in some embodiments, the light guide unit may include a first surface and a second surface, the light converter 362 is disposed between the light emitting surface of the light emitting unit 361 and the second surface of the light guide unit, and the light entrance area 313 is located on the second surface. The detection light beam 301 enters the interior of the light guide unit from the second surface of the light guide unit and can be directly irradiated onto the first surface; or, the light converter 362 is integrally formed with the light guide unit, and the light entrance area 313 is a partial surface of the light converter 362.

Optionally, in some embodiments, the number of the preset areas P3 may be multiple, for example but not limited to, different preset areas P3 are respectively provided near the top and bottom of the protective layer 300 .

Optionally, in some embodiments, the number of the light incident areas 313 may be multiple, for example but not limited to, different light incident areas 313 are respectively provided near the top and bottom of the protective layer 300 .

Optionally, in some embodiments, the number of the light sources 36 may be multiple, for example but not limited to, the light sources 36 may be arranged below the non-transparent area 310 corresponding to different positions of the non-transparent area 310 of the protective layer 300 .

Optionally, in some embodiments, the refractive index of the optical converter 362 is greater than the refractive index of the protective layer 300. It is understandable that when the detection beam 301 enters the protective layer 300 from the light incident area 313, refraction occurs at the interface between the optical converter 362 and the light incident area 313, and the refraction angle is greater than the incident angle.

Optionally, in some embodiments, the light source 36 may further include a circuit board, and the light-emitting unit 361 is connected to the circuit board, and the circuit board is used to provide the light-emitting unit 361 with an electrical signal required to emit the detection light beam 301, and the electrical signal is for example but not limited to current, voltage, etc.

Optionally, in some embodiments, the light source 36 may further include a circuit board, which is a flexible circuit board, and is electrically connected to the light-emitting unit 361. The circuit board may be fixedly connected or detachably connected to the side and/or bottom of a middle frame by glue, double-sided tape, adhesive, bolts, brackets, clips, slots, welding, and a middle frame.

Optionally, in some embodiments, the detection module 39 can be fixedly connected or detachably connected to the side and/or bottom of a middle frame by glue, double-sided tape, adhesive, bolts, brackets, clips, slots, welding, etc.

Optionally, in some embodiments, the number of the light emitting units 361 may be one or more, for example but not limited to: 1, 2, 3, 4.

Optionally, please refer to FIG. 10 , in a modified embodiment of the optical detection device 3, the light converter 362 is a prism, the light emitting surface of the light emitting unit 361 is in close contact with a light incident surface of the prism, the light emitting surface of the prism is in close contact with the lower surface 312 located in the non-transparent area 310, and the light emitting surface of the prism is opposite to the light incident area 313. Furthermore, the prism is a triangular prism. Furthermore, the angle between the light incident surface of the prism and the lower surface 312 is within the range of 60±5 degrees. In other or modified embodiments, the prism may also be a pentaprism, or other prisms.

Optionally, please refer to FIG. 11 , in a modified embodiment of the optical detection device 3, the light emitting unit 361 is arranged directly opposite to the light converter 362 and below the light converter 362. The light converter 362 is arranged close to the lower surface 312 located in the non-transparent area 310. The light converter 362 is an optical film with a sawtooth microstructure, and the sawtooth microstructure is directly opposite to the light emitting surface of the light emitting unit 361. The toothed microstructure can change the angle of the detection light beam 301 emitted by the light emitting unit 361 and then emit it into the interior of the protective layer 300. Further optionally, the lower surface 312 has a depression, and the sawtooth microstructure is located or at least partially located in the depression.

Optionally, the light emitting surface of the light emitting unit 361 for emitting the detection light beam 301 and the light converter 362 are spaced apart, and the spacing distance is, for example but not limited to: 1 mm, 2 mm, 3 mm, 4 mm, 5 mm.

Optionally, in some embodiments, the detection light beam 301 emitted from the light emitting unit 361 is a non-collimated light beam, which may have a light emitting angle range of 10 degrees to 140 degrees. For example, but not limited to, the detection light beam 301 emitted by the light emitting unit 361 has a light emitting angle of 50 degrees to 140 degrees. When the light emitting angle of the light emitting unit 361 is large, for example, greater than 50 degrees, the optical converter 362 can convert the detection light beam 301 emitted by the light emitting unit 361 into a non-collimated light beam with a larger divergence angle. The divergence angle mentioned here can be understood as the maximum angle between two light rays in the detection light beam 301 converted by the optical converter 362.

Optionally, the shape of the preset area P3 and/or the field of view area V3 may be square, circular, elliptical, etc., which is not limited in the embodiment of the present invention. Optionally, the field of view area V3 is circular, and its radius ranges from 2 to 5 mm, 3 to 4 mm, or 3 to 5 mm.

Optionally, the light-emitting unit 361 is one or more of, for example but not limited to, LED (light emitting diode), LD (laser diode), VCSEL (vertical cavity surface emitting laser), Mini-LED, Micro-LED, OLED (organic light emitting diode), QLED (quantum dot light emitting diode), or a light-emitting array composed of one or more of LED, LD, VCSEL, Mini-LED, Micro-LED, OLED, and QLED.

Optionally, in some embodiments, the protective layer 300 includes a transparent substrate and a light shielding film. The transparent substrate includes a portion located in the non-transparent area 310 and a portion located in the transparent area 320. The light shielding film is located below the transparent substrate opposite to the non-display area 310, and the light shielding film can be used to transmit the detection light beam 301 and intercept visible light.

The light converter 362 may be formed on the lower surface of the shading film, or the light converter 362 may be integrally formed with the shading film. Further optionally, the shading film may be omitted. At this time, the non-transparent area 110 of the protective layer 300 (i.e., the light-guiding unit) may be made of a material that is opaque to visible light. Further optionally, the shading film may be integrated on the lower surface, upper surface, or inside of the substrate. Further optionally, the shading film has a transmittance of greater than 50%, 60%, or 70% to the detection light beam 301. The shading film has a transmittance of less than 10%, 5%, or 1% to visible light. Further optionally, the shading film may be, for example but not limited to, infrared ink. In other or modified embodiments, the shading film may have different structures and functions according to design requirements, which is not limited to the embodiments of the present invention.

The optical detection device 3 uses a non-collimated detection beam 301, which is projected directly to the overlapping area of the preset area P3 and the field of view area V3, and the detection beam 301 is transmitted to the field of view area V3 through total reflection through the non-overlapping area of the preset area P3. The detection beam 301 is diffusely reflected at the contact point between the field of view area V3 and the ridge 1100 is received below the display module 31, thereby capturing the optical image of the fingerprint 1000 in the field of view area V3, thereby realizing fingerprint detection under the screen.

Please refer to FIG. 12 . In one embodiment of the present invention, the optical detection device 4 includes a light guide unit 400, a display module 41, a light source 46, and a detection module 49. The display module 41 is located below the light guide unit 400, and the display module 41 is used to emit a visible light beam through the light guide unit 400 to realize image display. The light source 46 is located below the light guide unit 400, and the light source 46 is used to emit a detection light beam 401. The light guide unit 400 includes an upper surface 411 and a lower surface 412 relative to each other. The upper surface 411 is the outer surface of the optical detection device 4. The optical detection device 4 further includes a protective layer 42 and an optical glue 43, and the upper surface of the optical glue 43 is arranged in close contact with the lower surface of the protective layer 42. In this embodiment, the light guide unit 400 is the protective layer 42 and the optical glue 43. The upper surface of the protective layer 42 is the upper surface 411.

The detection beam 401 includes a non-collimated beam. The detection beam 401 is incident from the lower surface 412 of the light guide unit 400 and can directly illuminate at least one preset area P4 on the upper surface 411 of the light guide unit 400. The preset area P4 is the direct illumination area of the detection beam 401 on the upper surface 411. The upper surface 411 also has a field of view area V4, and the field of view area V4 or at least a part of it is an area for the user's finger to touch when performing fingerprint detection. The detection module 49 is located below the light guide unit 400. In this embodiment, there is at least a partial overlapping area between the preset area P4 and the field of view area V4. Optionally, in some embodiments, the preset area P4 and the field of view area V4 do not overlap.

The protective layer 42 has a transparent area 420 and a non-transparent area 410. The non-transparent area 410 is located around or at the edge of the transparent area 420. The transparent area 420 is used to transmit a visible light beam. The non-transparent area 410 is used to block visible light. The visible light beam emitted by the display module 41 is emitted to the outside of the optical detection device 4 through the optical glue 43 and the protective layer 42 located in the transparent area 420 to achieve image display. The protective layer 42 located in the non-transparent area 410 is used to block the visible light beam emitted by the display module 41 and the visible light beam in the ambient light, so that the user cannot see the internal components of the optical detection device 4 in the non-transparent area 410.

The non-transparent area 410 includes an upper surface and a lower surface that are relatively arranged, and the transparent area 420 includes an upper surface and a lower surface that are relatively arranged. In this embodiment, the upper surface 411 of the light guide unit 400 is the upper surface of the protective layer 42, that is, the upper surface of the non-transparent area 410 and the upper surface of the transparent area 420. Optionally, in some embodiments, the upper surface 411 of the light guide unit 400 is the outer surface of the outermost layer of the optical detection device 4, and the user's finger can directly touch the upper surface 411 of the light guide unit 400. The lower surface 412 of the light guide unit 400 includes at least a portion of the lower surface of the optical glue 43.

The non-transparent area 410 of the protective layer 42 extends from the upper surface of the protective layer 42 to the lower surface. The protective layer 42 includes a transparent substrate 421 and a light shielding film 422. The transparent substrate 421 includes an upper surface and a lower surface opposite to each other. The light shielding film 422 is arranged on the edge area of the lower surface of the transparent substrate 421 and is located in the non-transparent area 410. The lower surface of the transparent substrate 421 faces the display module 41, and the upper surface of the transparent substrate 421 faces away from the display module 41. The non-transparent area 410 includes the light shielding film 422 and a portion of the transparent substrate 421 facing the light shielding film 422. The refractive index of the transparent substrate 421 is greater than the refractive index of air.

In the embodiment of the present application, the transparent substrate 421 is a single-layer structure, and its upper surface is the upper surface of the protective layer 42, that is, the upper surface 411 of the light guide unit 400. In this embodiment, the lower surface of the transparent substrate 421 is a part of the lower surface of the protective layer 42. The transparent area 420 is arranged side by side with the non-transparent area 410. The transparent substrate 421 includes a part located in the transparent area 420 and a part located in the non-transparent area 410.

However, the transparent substrate 421 can also be a multi-layer structure, and the multi-layer structures are stacked with each other, and the sizes are not limited to be the same. In addition, the multi-layer structures are arranged closely or adjacent to each other. For example, the shading film 422 is located between two adjacent layers of the transparent substrate 421, and the adjacent two layers are arranged closely or at intervals. However, the multi-layer structures can also be located on the same side of the shading film 422. In this case, the multi-layer structures are arranged closely to each other.

The transparent substrate 421 includes a soft structure and/or a hard structure. The transparent substrate 421 is made of, for example, one or more materials such as resin, glass, and sapphire.

The transmittance of the light shielding film 422 to the detection light beam 401 is greater than the transmittance to the visible light beam. The light shielding film 422 is a single-layer structure or a multi-layer structure. When the light shielding film 422 is a multi-layer structure, the transmittance of the light shielding film 422 to the detection light beam is the product of the transmittance of each layer structure to the detection light beam. Wherein, when the light shielding film 422 is a multi-layer structure, the multi-layer structure is, for example, arranged in close contact, close proximity or intervals.

The shading film 422 is, for example, infrared covering ink. However, the shading film 422 may also be other suitable structures, such as a multi-layer film structure, which can transmit the detection light beam and block the visible light. Preferably, the shading film 422 at least covers the light entrance area of the detection light beam on the lower surface of the transparent substrate 421. The optical glue 43 is located below the protective layer 42. The optical glue 43 is used to connect the display module 41 and the protective layer 42. The optical glue 43 covers at least a portion of the protective layer 42 located in the transparent area 420. Optionally, in some embodiments, the optical glue 43 covers at least a portion of the protective layer 42 located in the non-transparent area 410.

The display module 41 is located below the optical glue 43. The light source 46 is located below the non-transparent area 410 corresponding to the protective layer 42. The detection module 49 is located below the display module 41. Optionally, in other or modified embodiments, the detection module 49 may be located inside the display module 41.

At least a portion of the light source 46 is located in close contact with the protective layer 42 on the lower surface of the non-transparent area 410, which in this embodiment is also the lower surface of the light shielding film 422. The lower surface of the non-transparent area 410 has a light entrance area 413, and the detection light beam 401 enters the light guide unit 400 from the light entrance area 413. The detection light beam 401 entering the light guide unit 400 directly irradiates and covers the preset area P4.

In this embodiment, the preset area P4 and the field of view area V4 of the detection module 49 on the upper surface of the light guide unit 400 have an overlapping area. Optionally, in other or modified embodiments, for example but not limited to, the preset area P4 may be a part of the field of view area V4, which may be located in the field of view area V4. Optionally, in other or modified embodiments, for example but not limited to, the field of view area V4 may be a part of the preset area P4, which may be located in the preset area P4.

In this embodiment, the preset area P4 and the viewing area V4 are located on the upper surface of the protective layer 42. Optionally, in other or modified embodiments, at least part of the preset area P4 and/or the viewing area V4 is located on the upper surface of the protective layer 42.

The detection light beam 401 irradiated to the overlapping area of the preset area P4 and the field of view area V4 satisfies the condition of total reflection transmission in the light guide unit 400. Optionally, in other or modified embodiments, the detection light beam 401 entering the light guide unit 400 from the light entrance area 413 satisfies the condition of total reflection transmission in the light guide unit 400, that is, the detection light beam 401 irradiated to the preset area P4 satisfies the condition of total reflection transmission in the light guide unit 400. Optionally, in some embodiments, at least part of the detection light beam 401 irradiated to the non-overlapping area of the preset area P4 that does not overlap with the field of view area V4 satisfies the condition of total reflection transmission in the light guide unit 400.

The conditions for the total reflection transmission include: the detection light beam 401 is totally reflected at the upper surface 411 where it does not contact the ridge 1100 of the fingerprint 1000 , and is totally reflected at the lower surface 412 .

The detection light beam 401 is diffusely reflected at the contact point between the upper surface 411 and the ridge 1100 of the fingerprint 1000 , and the detection light beam 401 after diffuse reflection is irradiated in all directions.

In this embodiment, the refractive indexes of the protective layer 42 and the optical glue 43 of the light guide unit 400 are substantially the same, and for the convenience of description, they are referred to as the refractive index of the light guide unit 400. The refractive index of the light guide unit 400 is greater than the refractive index of air. Optionally, in some embodiments, the refractive index of the protective layer 42 is greater than or equal to the refractive index of the optical glue 43. Optionally, in some embodiments, the light guide unit 400 may be a protective layer made of a transparent material, and the upper surface 411 of the light guide unit 400 is the surface that the user's finger directly contacts when using the optical detection device 1. The portion of the protective layer 42 located in the non-transparent area 410 and the portion of the protective layer 42 located in the transparent area 420 are integrally formed. The protective layer 42 and the optical glue 43 are arranged in close contact or laminated. The protective layer 42 is connected to the display module 41 through the optical glue 43.

Optionally, the optical adhesive 43 is made of a transparent material, and the refractive index of the optical adhesive 43 is less than or equal to the refractive index of the protective layer 42. Of course, the present invention is not limited to this, and in some embodiments, the refractive index of the optical adhesive 43 or a part thereof may also be greater than the refractive index of the protective layer 42.

During fingerprint detection, the ridge 1100 of the fingerprint 1000 contacts the upper surface of the light guide unit 400, and the valley 1200 of the fingerprint 1000 is opposite to the upper surface 411 of the light guide unit 400 through the spacer. The detection light beam 401 is diffusely reflected at the ridge 1100, and is totally reflected at the valley 1200. The detection light beam 401 diffusely reflected at the ridge 1100 passes through the protective layer 42 located in the transparent area 420, the optical glue 43, and the display module 41 to reach the detection module 49. The detection module 49 receives the detection light beam 401 and converts it into an electrical signal, which can be used for image generation or detection of the fingerprint 1000.

The optical detection device 4 uses a non-collimated detection beam 401, which is projected directly to the overlapping area of the preset area P4 and the field of view area V4, and the detection beam 401 is transmitted to the field of view area V4 through total reflection through the non-overlapping area of the preset area P4. The detection beam 401 is diffusely reflected at the contact point between the field of view area V4 and the ridge 1100 is received below the display module 41, thereby capturing an optical image of the fingerprint 1000 in the field of view area V4, thereby realizing fingerprint detection under the screen.

Please refer to FIG. 13 . In one embodiment of the present invention, the optical detection device 5 includes a protective layer 52 , an optical adhesive 53 , a light source 56 , a display module 51 , and a detection module 59 .

The display module 51 includes an array substrate 541, a liquid crystal layer 542, an alignment film 543, a common electrode 544, a color filter 545, a substrate 546, and a polarizer 547 stacked in sequence from bottom to top. In this embodiment, the display module 51 is, for example but not limited to, a liquid crystal display module. The common electrode 544, the color filter 545, the substrate 546, and the polarizer 547 together constitute a color filter substrate of the display module 51.

Optionally, in some embodiments, the display module 51 further includes a backlight unit located below the array substrate 541. In this case, the array substrate 541, the liquid crystal layer 542, the alignment film 543, the common electrode 544, the color filter 545, the substrate 546, and the polarizer 547 can be considered as a display unit, and the backlight unit is located below the display unit. The protective layer 52, the display unit, and the backlight unit together constitute a display device.

The protective layer 52 includes an upper surface and a lower surface that are arranged opposite to each other. The light source 56 is located below the upper surface of the protective layer 52 and is spaced apart from the upper surface. The light source 56 is used to project a non-collimated detection beam 501 onto the upper surface. The detection beam 501 can at least be transmitted by total reflection inside the protective layer 52. The area where the detection beam 501 that enters the interior of the protective layer 52 from the light source 56 is transmitted and first reaches the upper surface is defined as the preset area P5. The detection module 59 has a field of view area V5 on the upper surface. When there is no finger contact on the preset area P5, there is a detection beam that is totally reflected in the field of view area V5. When there is a finger contact on the field of view area V5, the detection beam 501 is diffusely reflected at the fingerprint ridge 1100 that is in contact with the field of view area V5, and the detection beam 501 is totally reflected at the field of view area V5 where it is directly opposite to the fingerprint valley 1200. At least a portion of the diffusely reflected detection light beam 501 passes through the protective layer 52 and is received by the detection module 59 , and the detection module 59 converts the received detection light beam into a corresponding electrical signal.

Optionally, in some embodiments, the light source 56 is located below the protective layer 52. The optical glue 53 is located below the protective layer 52. The display module 51 is located below the optical glue 53, and the detection module 59 is located below the display module 51. Optionally, in other or modified embodiments, the detection module 59 may be located inside the display module 51.

In this embodiment, the protective layer 52 , the optical adhesive 53 , and the polarizer 547 together constitute a light guide unit (not numbered) of the optical detection device 1 . The light guide unit includes an upper surface 511 and a lower surface 512 that are opposite to each other.

The protective layer 52 has a non-transparent area 510 and a transparent area 520. The non-transparent area 510 includes an upper surface (not marked) and a lower surface (not marked) that are relatively arranged. The transparent area 520 includes an upper surface (not marked) and a lower surface (not marked) that are relatively arranged. The transparent area 520 can transmit visible light and invisible light, and the non-transparent area 510 can block visible light and transmit invisible light. In this embodiment, the upper surface 511 of the light guide unit includes the upper surface of the non-transparent area 510 and the upper surface of the transparent area 520. The lower surface 512 of the light guide unit includes at least a portion of the lower surface of the polarizer 547.

The upper surface of the optical adhesive 53 is disposed in close contact with the lower surface of the protective layer 52. The upper surface of the polarizing plate 517 is disposed in close contact with the lower surface of the optical adhesive 53.

The light source 56 is located below the non-transparent area 510 of the protective layer 52. The display module 51 is located below the optical glue 53. The detection module 59 is located below the display module 51. Optionally, in other or modified embodiments, the detection module 59 may be located inside the display module 51.

Optionally, in some embodiments, the detection module 59 may include an image sensor, which can receive the detection light beam 501 and convert it into an electrical signal, and the electrical signal is, for example but not limited to, image data of the fingerprint 1000. Further optionally, for example but not limited to, the detection module 59 may also include a lens and/or a collimator located above the image sensor, and the detection light beam 501 is imaged on the image sensor after passing through the lens and/or the collimator.

When the field of view area in the embodiment of the present application is a local area on the protective layer facing the display area, since the optical detection device 5 uses diffuse reflection for fingerprint sensing, the size and volume of the detection module 59 of the present application can be smaller, thereby being suitable for under-screen fingerprint detection needs while meeting the requirements for lightweight electronic products such as mobile phones.

At least a portion of the light source 56 is in close contact with the lower surface of the non-transparent area 510 of the protective layer 52. The lower surface of the non-transparent area 510 has a light entrance area 513. The detection light beam 501 enters the light guide unit of the optical detection device 5 from the light entrance area 513. The directly irradiated area on the upper surface 511 of the light guide unit in the detection light beam 501 entering the light guide unit is defined as a preset area P5. In this embodiment, the preset area P5 is located on the upper surface of the transparent area 520. Optionally, in some embodiments, at least a portion of the preset area P5 is located on the upper surface of the transparent area 520.

The detection module 59 has a field of view region V5 on the upper surface 511 of the light guide unit. In this embodiment, the field of view region V5 is located on the upper surface of the transparent region 520. Optionally, in some embodiments, at least part of the field of view region V5 is located on the upper surface of the transparent region 520.

In this embodiment, the preset area P5 and the field of view area V5 have an overlapping area. Optionally, in other or modified embodiments, the preset area P5 may be a part of the field of view area V5, which may be located in the field of view area V5. In other or modified embodiments, the field of view area V5 may be a part of the preset area P5, which may be located in the preset area P5. Optionally, in other or modified embodiments, the preset area P5 and the field of view area V5 do not overlap.

Optionally, in some embodiments, for example but not limited to, the preset area P5 is a part of the field of view area V5, and the area of the overlapped area between the preset area V5 and the field of view area V5 is not less than 50%, 60%, 70%, 80%, or 90% of the area of the field of view area V5. In this way, when a finger touches above the field of view area V5, there is enough detection light diffusely reflected by the ridge of the fingerprint and enters the detection module 59, thereby ensuring the fingerprint detection effect.

If there is not enough detection light directly incident on the field of view area V5, when the finger touches the preset area P5, a part of the fingerprint ridges will diffusely reflect the detection light beam, and the diffusely reflected detection light beam will no longer be transmitted to the remaining fingerprint ridges that have not touched the detection light beam, that is, the ridges of the fingerprint adjacent to the detection light beam will cut off the detection light beam, while the ridges of the fingerprint far away from the detection light beam will not touch the detection light beam or will touch less of the detection light beam. Therefore, there are a part of the fingerprint ridges that do not touch the detection light beam, and thus, the detection module 59 cannot obtain a complete fingerprint image based on the received detection light beam.

In addition, in addition to directly projecting the detection beam 501 to the overlapping area, the light source 56 also projects the detection beam 501 to an area outside the overlapping area and adjacent to the light source 56, and at least part of the detection beam 501 projected to this area satisfies the condition of total reflection transmission in the light guide unit. When this part of the detection beam 501 is transmitted to the field of view area V5 by total reflection and encounters the ridge 1100 of the fingerprint, diffuse reflection occurs and is emitted to the detection module 59, which can further improve the detection accuracy of the fingerprint and obtain a better fingerprint detection effect.

Optionally, in some embodiments, the preset area P5 is a part of the field of view area V5 or the field of view area V5 is a part of the preset area P5, and the maximum distance between the edge of the preset area P5 and the edge of the field of view area V5 is not greater than 1 mm, 2 mm, or 3 mm.

Optionally, in some embodiments, part or all of the detection light beam 501 irradiated to the preset area P5 satisfies the condition of total reflection transmission in the light guiding unit.

Optionally, a portion of the detection light beam 501 that enters the light guide unit from the light incident area 513 irradiates a portion of the upper surface of the protective layer 52 outside the preset area P5, and this portion of the detection light beam 501 can be reflected or totally reflected inside the light guide unit, and can irradiate the field of view area V5 after reflection or total reflection. A portion of the detection light beam 501 that can enter the field of view area V5 after reflection or total reflection is diffusely reflected at the ridge 1100 of the fingerprint 1000, and can be received by the detection module 59 after being emitted through the lower surface of the light guide unit.

The conditions for the total reflection transmission include: the detection light beam 501 is totally reflected at the upper surface 511 where it does not contact the ridge 1100 of the fingerprint, and is totally reflected on the lower surface 512 .

The detection light beam 501 is diffusely reflected at the contact point between the upper surface 511 and the ridge 1100 of the fingerprint, and the detection light beam 501 after diffuse reflection is irradiated in all directions.

In this embodiment, the refractive indexes of the polarizer 547, the optical glue 53, and the protective layer 52 are substantially the same and greater than the refractive index of air. The light guide unit can be regarded as a uniform medium. Optionally, in some embodiments, the upper surface of the protective layer 52, that is, the upper surface 511 of the light guide unit, is also the outer surface of the optical detection device 5 that the user's finger directly touches when performing fingerprint detection.

The substrate 546 is made of a transparent material, for example but not limited to glass or plastic. The color filter 545 is used to filter white visible light into red light, green light, blue light or other color light. The color filter 545 is made of, for example but not limited to resin or other materials. The common electrode 544 is, for example but not limited to, a transparent electrode, such as an ITO electrode. The alignment film 543 is used to align the liquid crystal molecules of the liquid crystal layer 542.

In this embodiment, the light guiding unit includes the protective layer 52, the optical glue 53 located below the protective layer, and the polarizing plate 547 located below the optical glue.

Optionally, in other or modified embodiments, the light guide unit protective layer 52 , the optical glue 53 located below the protective layer 52 , the polarizer 547 located below the optical glue 53 , and the substrate 546 located below the polarizer 547 .

Optionally, in other or modified embodiments, the light guiding unit includes a protective layer 52 , an optical adhesive 53 located below the protective layer 52 , a polarizer 547 located below the optical adhesive 53 , a substrate 546 located below the polarizer 547 , and a color filter 545 .

Optionally, in other or modified embodiments, the light guiding unit includes a protective layer 52 , an optical adhesive 53 located below the protective layer 52 , a polarizer 547 located below the optical adhesive 53 , a substrate 546 located below the polarizer 547 , a color filter 545 , and a common electrode 544 .

Optionally, in other or modified embodiments, the light guiding unit includes a protective layer 52, an optical glue 53 located below the protective layer 52, a polarizer 547 located below the optical glue 53, a substrate 546 located below the polarizer 547, a color filter 545, a common electrode 544, and an alignment film 543.

Optionally, in other or modified embodiments, the light guiding unit includes a protective layer 52, an optical glue 53 located below the protective layer 52, a polarizer 547 located below the optical glue 53, a substrate 546 located below the polarizer 547, a color filter 545, a common electrode 544, an alignment film 543, and a liquid crystal layer 542.

Optionally, in other or modified embodiments, the light guiding unit includes a protective layer 52, an optical glue 53 located below the protective layer 52, a polarizer 547 located below the optical glue 53, a substrate 546 located below the polarizer 547, a color filter 545, a common electrode 544, an alignment film 543, a liquid crystal layer 542, and an array substrate 541.

Optionally, in other or modified embodiments, the display module 51 may also have other different structures. For example, but not limited to, the array substrate 541, liquid crystal layer 542, alignment film 543, common electrode 544, color filter 545, substrate 546, and polarizer 547 in this embodiment may be partially omitted, changed, replaced, combined, etc. Those skilled in the art may understand that the embodiments and modified embodiments based on the inventive purpose of the present invention all fall within the protection scope of the present invention.

Optionally, in other or modified embodiments, the light source 56 includes a light-emitting unit and a light converter, the structure and function of the light converter are substantially the same as those of the aforementioned light converter 362, and the structure and function of the light-emitting unit are substantially the same as those of the aforementioned light-emitting unit 361.

During fingerprint detection, the ridge 1100 of the fingerprint 1000 contacts the upper surface of the light guide unit, and the valley 1200 of the fingerprint 1000 is opposite to the upper surface of the light guide unit through the spacer. The detection light beam 501 is diffusely reflected at the ridge 1100, and is totally reflected at the valley 1200. The detection light beam 501 diffusely reflected at the ridge 1100 passes through the transparent area 520 of the protective layer 52, the optical glue 53, and the display module 51 to reach the detection module 59. The detection module 59 receives the detection light beam 501 and converts it into an electrical signal, which can be used for image generation or detection of the fingerprint 1000.

Optionally, in some embodiments, the detection module 59 may further include a processor and a memory, and the processor may obtain fingerprint information of the user according to the received detection beam 501, such as, but not limited to, a fingerprint image including ridge/valley light and dark contrast. The memory pre-stores biometric information data, and the processor may compare the obtained fingerprint information with the pre-stored fingerprint information data, thereby realizing fingerprint detection and identification. By detecting and identifying fingerprints, the optical detection device 5 of the present invention may be used for locking or unlocking electronic products, online payment service verification, identity verification of financial systems or public security systems, access verification of access control systems, and other products and application scenarios.

In the present invention, the optical detection device 5 can be a mobile phone, a tablet computer, a smart watch, an augmented reality/virtual reality device, a human motion detection device, an autonomous vehicle, a smart home device, a security device, an intelligent robot, or a component thereof.

It should be noted that the term "closely attached" in the description of the present invention and the claims may mean, for example but not limited to: being combined together by lamination, or being closely attached or close with a gap, or being closely connected by an optical medium. The present invention does not limit this.

The optical detection device 5 of the present invention uses a light guide unit as a light guide medium for the detection light beam 501, and injects the detection light beam 501 into the light guide unit at an angle that satisfies the total reflection transmission condition and can irradiate the preset area P5. The preset area P5 is the irradiation area of the detection light beam 501 on the upper surface 511 of the light guide unit, and the field of view area V5 is the area for the user's finger to touch during fingerprint detection.

The preset area P5 and the field of view area V5 have an overlapping area, and the detection light beam 501 irradiated to the overlapping area is equivalent to being able to directly irradiate the ridge 1100 of the fingerprint 1000. The detection light beam 501 irradiated to the non-overlapping area of the preset area P5 that does not overlap with the field of view area V5 can reach the field of view area V5 after multiple total reflection transmissions.

Since there is an air gap between the valley 1200 of the fingerprint 1000 and the field of view area V5, the detection light beam 501 is totally reflected at the position where the field of view area V5 and the valley 1200 are opposite, and can be totally reflected and transmitted in the light guide unit. Since the ridge 1100 of the fingerprint 1000 is in direct contact with the preset area, the detection light beam 501 is diffusely reflected at the position where the field of view area V5 and the ridge 1100 are in contact, and a part of the diffusely reflected detection light beam 501 can be received by the detection module 59 after passing through the lower surface of the transparent area 520. The detection light beam 501 is non-collimated light, including but not limited to non-collimated near-infrared light.

The detection module 59 receives the diffusely reflected detection light beam 501 for imaging. Since the characteristic of the diffusely reflected light beam is that it diverges in all directions in space, at least part of the diffusely reflected detection light beam 501 is emitted from the lower surface of the light guide unit. At least part of the detection light beam 501 emitted from the lower surface of the light guide unit can be received by the detection module 59. The detection light beam 501 can have different incident angles when entering the detection molding 59.

Therefore, the detection module 59 can be roughly set at a position directly below the field of view area V5 to receive the diffusely reflected detection light beam 591. Of course, the detection module 59 can be set at any position of the optical detection device 5, as long as the detection module 59 can receive the diffusely reflected detection light beam 501 from the ridge 1100, it is within the protection scope of the present invention. The present invention is not limited to this. The horizontal distance between the detection module 59 and the light source 56 can be less than or equal to the horizontal distance between the field of view area V5 and the light source 56. In this embodiment, the horizontal distance between the detection module 59 and the light source 56 is approximately 10 to 15 mm. Of course, optionally, in some embodiments, the detection module 59 can be set adjacent to the light source 56, and the horizontal distance between the detection module 59 and the light source 56 can be less than 10 mm, 8 mm, or 5 mm.

When the detection module 59 is located below the field of view area V5, the path of the detection light beam 501 transmitted in the light guide unit is shorter, and the detection light beam 501 does not need to be fully reflected and transmitted in other areas of the light guide unit. Therefore, the energy loss of the detection light beam 501 received by the detection module 59 is small. In addition, as mentioned above, the size or volume of the detection module 59 is small, so that it can meet the requirements of being set inside electronic products such as mobile phones.

Of course, in some embodiments, collimated light can also be used as the detection beam. It can be understood that if a collimated light beam is used as the detection beam, the width of the corresponding preset area will be the same as the width of the light incident area. However, since the light incident area 513 is located on the lower surface of the non-transparent area of the protective layer 52, the transparent area 520 is opposite to the display module 51, the non-transparent area 510 and the display module 51 are not arranged opposite each other, or most of the non-transparent area 510 is not opposite to the display module 51. The display module 51 is used to display images, and the transparent area 520 of the protective layer 52 can transmit visible light, but the non-transparent area 510 of the protective layer 52 has a very low transmittance to visible light. In other words, the non-transparent area 510 is a portion outside the visible display area of the optical detection device 5, and the portion outside the display area is usually called a border area. Since the mainstream electronic products capable of image display are now pursuing full screens and narrow borders, the border area of the optical detection device 5 is narrow, and the width of the non-transparent area 510 is very small, so that the width of the light entrance area 513 is also very small. Correspondingly, the width of the preset area will also be very small. Due to the parallel transmission characteristics of collimated light, the following problems are likely to occur at this time: there are certain positions on the field of view area V5 that cannot be directly irradiated by the detection beam, and no detection beam can reach these positions of the field of view area V5 after total reflection. This situation in the field of view area V5 causes some fingerprints corresponding to these positions to not be detected. Therefore, although the detection beam of collimated light can also be used for fingerprint detection or optical imaging under the screen, it has a major disadvantage, and the detection efficiency and imaging quality of fingerprints are not as good as the detection beam 501 of non-collimated light.

Therefore, the optical detection device 5 and its modified embodiments of the present invention use a non-collimated detection beam 501, which can directly irradiate the entire preset area P5, so that the detection beam 501 that directly reaches the fingerprint ridge has more energy and can detect the fingerprint information of the entire preset area P5. The optical detection device 5 of the present invention and its modified embodiments have a good fingerprint detection effect. Similarly, the optical detection devices 1, 3, 4, 5 of the present invention and their modified embodiments have a good fingerprint detection effect.

Of course, in some other embodiments, a non-collimated detection beam 501 may also be used. The non-collimated detection beam 501 passes through the light guide unit of the optical detection device 5 after total reflection and can be further received by a detection module. At this time, it is equivalent to the optical detection device 5 receiving the totally reflected detection beam 501 for imaging and detection. For example, the non-collimated detection beam 501 passes through the light guide unit of the optical detection device 5 after total reflection in the preset area P5 and is further received by the detection module. However, in these embodiments, it is necessary to set an optical element with a larger refractive index on the lower surface of the light guide unit so that the detection beam 501 can be emitted from the lower surface after total reflection on the upper surface of the light guide unit. Setting the optical element will inevitably lead to an increase in the cost and assembly complexity of the optical detection device 5. Moreover, in these embodiments, since the detection beam 501 is a non-collimated light, it has a certain divergence angle when projected on the preset area P5, so the width of the preset area P5 is greater than the width of the light entrance area 513. Correspondingly, the reflected light of the detection light beam 501 after total reflection in the preset area P5 also has a certain divergence angle. Therefore, it can be understood that the detection light beam 501 that is totally reflected to the lower surface of the light guide unit is emitted from the lower surface, and the width of the emission area corresponding to the emission light beam 501 on the lower surface is greater than the width of the preset area P5. Therefore, the fingerprint image formed by the detection light beam 501 that is totally reflected to the lower surface and emitted will show a relatively serious magnification phenomenon, thereby causing the fingerprint image to deform. In addition, the emission area of the detection light beam 501 on the lower surface of the light guide unit is relatively large. Accordingly, the detection module for receiving the emitted detection light beam 501 requires a larger volume and area to receive the detection light beam 501 from the emission area. For example, but not limited to, the detection module requires a larger photosensitive area, or a larger lens, etc. For example, the detection module needs to be equipped with a relatively large lens, and the cross-sectional area of the lens needs to be no less than the area of the preset area P5; or the detection module needs to be equipped with a relatively large image sensor, and the area of the photosensitive area of the image sensor that receives the detection beam 501 needs to be no less than the area of the preset area P5. In this way, in order to set up the detection module, it is even necessary to occupy the original space of other components, which will affect the overall volume, cost and assembly of the optical detection device 5, and it is not suitable for the needs of being set inside electronic products such as mobile phones.

Furthermore, according to the total reflection optical principle, the horizontal distance between the detection light beam 501 after total reflection and the light source 56 in the exit area of the lower surface of the light guide unit is greater than the horizontal distance between the preset area P5 and the light source 56. Moreover, the exit direction of the detection light beam 501 emitted from the exit area follows the principle of reflection and refraction, so the detection module that receives these detection light beams 501 needs to be set on the corresponding exit light path to ensure the reception and imaging effect. Therefore, the horizontal distance between the detection module and the light source 56 is greater than the horizontal distance between the preset area P5 and the light source 56. The detection module needs to be located on the side of the preset area P5 away from the light source 56, and the detection light beam 501 needs to be transmitted in a longer path inside the light guide unit to be emitted, and needs to be transmitted in the part outside the preset area P5 of the light guide unit. In this case, if the light guide unit between the preset area P5 and the above-mentioned exit area is broken or damaged, the detection light beam 501 will not be able to smoothly exit from the exit area of the lower surface of the light guide unit through total reflection.

In addition, in some embodiments, the preset area P5 and the field of view area V5 do not overlap or the overlap is very small, so that fingerprint detection is almost completely dependent on the detection light beam of the preset area P5 being irradiated to the field of view area V5 after total reflection. Once the light guide unit or protective layer between the light source and the preset area P5 is broken or damaged, or the light guide unit or protective layer between the preset area P5 and the field of view area V5 is broken or damaged, the fingerprint detection effect will be reduced, and even normal detection will not be possible. In other words, when the area outside the preset area P5 of the light guide unit is damaged, it will affect the reception and imaging of the detection light beam, resulting in a decrease in user experience.

Therefore, the detection module 59 of the fingerprint detection device 5 of the present invention receives the detection light beam 501 transmitted after diffuse reflection at the ridge 1100. Since the characteristic of diffuse reflection is to reflect in all directions in space, no additional optical element is required to guide the detection light beam out of the light guide unit, and the detection light beam 501 received by the detection module 59 does not have the problem of image magnification or deformation. The volume of the detection module 59 of the present invention can be small, and the area of the photosensitive area of the detection module 59 receiving the detection light beam 501 can be smaller than the area of the field of view area V5. Optionally, in some embodiments, the detection module 59 includes an image sensor and an ultra-macro lens located above the image sensor, wherein the ultra-macro lens is used to converge the detection light beam 501 emitted from the light guide unit after diffuse reflection onto the image sensor, and the image sensor is used to convert the detection light beam 501 into a corresponding electrical signal. The vertical projection of the ultra-macro lens and the image sensor on the upper surface of the light guide unit is located within the field of view area V5, and the area of the vertical projection is smaller than the area of the field of view area V5.

Optionally, in some embodiments, the light guide unit includes a first surface and a second surface, the first surface and the second surface are arranged opposite to each other, wherein the first surface is the upper surface and the second surface is the lower surface. Of course, it is changeable that in some embodiments, the second surface may also be a side surface of the light guide unit, and the first surface is the upper surface of the light guide unit. For example, but not limited to, the second surface is connected between the upper surface and the lower surface of the light guide unit, and the angle between the second surface and the upper surface is an acute angle. The light source is arranged on one side of the second surface, and the light entrance area is on the second surface. The embodiments of the present invention do not limit the positions of the first surface and the second surface of the light guide unit. It only needs to detect that the light beam enters the light guide unit from the second surface and can be totally reflected in the light guide unit, which falls within the protection scope of the present invention.

The light source and detection module of the optical detection device of the present invention are both arranged below the light guide unit. The light source emits a non-collimated detection light beam, which is projected directly to the overlapping area of the preset area and the field of view area, and the detection light beam passing through the non-overlapping area of the preset area is transmitted to the field of view area by total reflection. When the fingerprint contacts the field of view area, the detection light beam is diffusely reflected at the ridge and then passes through the light guide unit and can be received by the detection module. The detection module receives the diffusely reflected detection light beam and converts it into an electrical signal to obtain fingerprint information, thereby realizing fingerprint detection, fingerprint optical imaging, fingerprint recognition, etc. under or inside the screen. The optical detection device of the present invention has a good fingerprint detection effect.

The structures and positions of the light guide unit, display module, light source, light converter, light-emitting unit, light incident area, preset area, field of view area, etc. in the above-mentioned embodiments or modified embodiments of the present invention and the corresponding modified settings can also be applied to other embodiments disclosed in the present invention. The embodiments obtained therefrom and their replacement, deformation, combination, splitting, expansion, omission, etc. all fall within the protection scope of the present invention.

It should be noted that the light emitting surface, light incident surface, etc. that may appear in the description of the present invention may be an actual physical surface or an imaginary surface, which does not affect the implementation of the technical solution of the present invention and belongs to the scope of the present invention. In addition, the terms "overlap", "coincidence" and "overlap" that may appear in the description of the present invention should be understood to have the same meaning and can be replaced with each other.

It should be noted that those skilled in the art can understand that, without paying any creative work, part or all of the embodiments of the present invention, as well as part or all of the deformation, replacement, change, split, combination, expansion, etc. of the embodiments should be considered to be covered by the inventive ideas of the present invention and belong to the protection scope of the present invention.

Any reference in this specification to "one embodiment," "an embodiment," "an example embodiment," etc., indicates that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Such phrases appearing in different places in this specification do not necessarily all refer to the same embodiment. In addition, when a particular feature or structure is described in connection with any embodiment, it is claimed that it is within the skill of those skilled in the art to implement such feature or structure in connection with other embodiments of these embodiments.

The orientation or positional relationship indicated by “length”, “width”, “up”, “down”, “left”, “right”, “front”, “rear”, “back”, “front”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, etc. that may appear in the specification of the present invention is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. Similar numbers and letters represent similar items in the drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of the present invention, the terms “first”, “second”, etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of “multiple” or “multiple” is at least two or two, unless otherwise clearly and specifically defined. In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. The terms used in the claims should not be understood as limiting the invention to the specific embodiments disclosed in this specification. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims (12)

1. An optical detection device, comprising: A light guide unit, comprising a first surface and a second surface that are different; a detection module, located below the light guide unit, wherein the first surface is a surface of the light guide unit on a side facing away from the detection module, the detection module is used to receive a detection light beam emitted from the light guide unit, and the detection module has a field of view area on the first surface; and a light source, used for projecting the detection light beam into the interior of the light guide unit through the second surface, and the detection light beam entering the interior of the light guide unit can be transmitted by total reflection in the light guide unit, and an area where the detection light beam entering the interior of the light guide unit from the light source is transmitted and first reaches the first surface is defined as a preset area, and there is an overlapping area between the preset area and the field of view area, and the overlapping area accounts for an area ratio of greater than or equal to 30% of the field of view area; When the user's finger is not touching the preset area, the detection light beam is totally reflected in the field of view area; When a user's finger touches the field of view area, the detection light beam is diffusely reflected at the fingerprint ridge in contact with the field of view area, and the detection light beam is totally reflected at the point where the field of view area is opposite to the fingerprint valley, wherein at least a portion of the diffusely reflected detection light beam passes through the light guiding unit and is received by the detection module, and the detection module converts the received detection light beam into a corresponding electrical signal to obtain fingerprint information. 2. The optical detection device as described in claim 1 is characterized in that the preset area is the field of view area; or, the preset area is located in the field of view area, and the area of the preset area is smaller than the area of the field of view area; or, the field of view area is located in the preset area, and the area of the field of view area is smaller than the area of the preset area; or, part of the preset area overlaps with part of the field of view area; the part of the preset area that does not overlap with the field of view area is defined as a non-overlapping area, and at least part or all of the non-overlapping area is closer to the light source than the overlapping area. 3. The optical detection device as described in claim 2 is characterized in that, when there is no user finger touching the field of view area, the detection light beam that can be totally reflected in the field of view area includes the detection light beam that reaches the field of view area after multiple total reflection transmissions from the non-overlapping area, or/and the detection light beam that reaches the overlapping area for the first time after entering the light guide unit from the light source and satisfies the total reflection in the overlapping area. 4. The optical detection device as described in claim 1 is characterized in that the second surface is arranged opposite to the first surface, and the area where the light source enters on the second surface is defined as the light entrance area, and the detection light beam enters the interior of the light guiding unit from the light entrance area and is transmitted to the preset area; there is a shortest straight line between the light entrance area and the overlapping area, and the angle between the shortest straight line and the normal of the overlapping area is not less than the critical angle of the detection light beam for total reflection transmission in the light guiding unit, or the detection light beam with the shortest distance from the light entrance area to the overlapping area meets the condition of total reflection transmission in the light guiding unit, or the detection light beam directly projected by the light source to the overlapping area through the second surface meets the condition of total reflection transmission in the light guiding unit. 5. The optical detection device as described in claim 1 is characterized in that the light guiding unit includes an upper surface and a lower surface arranged opposite to each other, the detection module is arranged below the lower surface, and is used to receive the detection light beam emitted from the lower surface, the first surface is the upper surface; the second surface is the lower surface, or the second surface is the inclined surface or side surface of the light guiding unit, and the inclined surface or side surface is located between the upper surface and the lower surface. 6. The optical detection device as described in claim 1 is characterized in that the light source includes a light-emitting unit and a light converter, the light-emitting unit is used to emit a non-collimated detection light beam, and the light converter is used to convert the angle of the non-collimated detection light beam entering the light-guiding unit, so that the detection light beam can directly irradiate the preset area after entering the light-guiding unit and can be transmitted by total reflection within the light-guiding unit. 7. The optical detection device as described in claim 6 is characterized in that the light converter is arranged between the light emitting surface of the light emitting unit and the second surface, or the light converter and the light guiding unit are integrally formed, and the light incident area of the detection light beam on the second surface is a partial surface of the light converter. 8. The optical detection device as described in claim 1 is characterized in that the optical detection device also includes a display device, the display device includes a protective layer and a display module, the protective layer includes an upper surface and a lower surface arranged opposite to each other, the display module is arranged on the side of the lower surface of the protective layer for performing image display, and the detection module is used to receive the detection light beam emitted from the light guide unit through at least part of the display module; the upper surface of the protective layer is the first surface of the light guide unit. 9. The optical detection device as described in claim 8 is characterized in that the protective layer includes a transparent area and a non-transparent area located in the transparent area, the display module is used to emit a visible light beam through the transparent area, the light incident area of the light source on the second surface is located in the non-transparent area, and the wavelength of the detection light beam is different from the wavelength of the visible light beam. 10. The optical detection device as described in claim 8 is characterized in that the display device also includes optical glue for connecting the protective layer and the display module, and the light guiding unit includes or is the protective layer, or the light guiding unit includes or is the protective layer and the optical glue, or the light guiding unit includes or is the protective layer, the optical glue, and at least a part of the display module. 11. The optical detection device according to claim 10, characterized in that the protective layer comprises a transparent substrate, the refractive index of the optical glue is greater than or equal to the refractive index of the transparent substrate, and the refractive index of the transparent substrate is greater than the refractive index of air. 12. The optical detection device as described in claim 8 is characterized in that the area where the display module displays images is defined as a display area, and the area around the display area where images cannot be displayed is defined as a non-display area; the field of view area is located directly above a local area of the display area.