CN114755800B - Lens module, electronic device and depth of field extension method - Google Patents

Abstract

The present application discloses a lens module, an electronic device and a depth of field extension method, wherein the lens module includes a lens assembly, a meta-lens and a polarized light image sensor assembly; an incident light beam is converged by the lens assembly to form an outgoing light beam; the meta-lens is arranged on a side of the lens assembly away from the incident light beam, and is used to adjust the focal length of the outgoing light beam so that the distance between the convergence focal distance of the first polarized light and the convergence focal distance of the second polarized light is increased; the polarized light image sensor assembly is arranged on a side of the meta-lens away from the lens assembly to receive the light beam after convergence by the meta-lens. The lens module, electronic device and depth of field extension method provided by the present application can not only effectively extend the depth of field, but also meet the user's demand for thin and light electronic products, and are highly comfortable to use.

Description

Lens module, electronic device and depth of field extension method

Technical Field

The present application belongs to the field of optical technology, and specifically relates to a lens module, an electronic device and a depth of field extension method.

Background technique

As the functions of electronic products become increasingly powerful, users' pursuit of thinner and lighter bodies and image quality has driven the continuous upgrading of electronic products. The current shooting structure of electronic products includes a lens module and an image sensor. The light passing through the lens module will produce an allowable circle of confusion on the image plane where the image sensor is located, which corresponds to the depth of field range in which a clear image can be formed before and after the photographed object. As the aperture of electronic products continues to increase, the depth of field of the lens module is also constantly shortening. Especially for the application of high-magnification microscopic optical photography, usually because the object distance is very short, the depth of field is relatively shallow, and the slightest movement on the object side will make the image blurred, greatly affecting the user experience.

In the related art, the shallow depth of field can be effectively improved by using a variable aperture design or an autofocus motor to balance the focus. However, these components are heavy and bulky, which inevitably increases the weight and thickness of electronic products, which is contrary to the user's demand for thinner and lighter electronic products, greatly affecting the user experience.

Summary of the invention

The present application aims to provide a lens module, an electronic device and a depth of field extension method to at least solve one of the problems of the background technology.

In order to solve the above technical problems, this application is implemented as follows:

In a first aspect, an embodiment of the present application provides a lens module, comprising:

A lens assembly, through which an incident light beam is converged to form an outgoing light beam;

A meta-lens, the meta-lens being disposed on a side of the lens assembly away from the incident light beam, and being used to adjust the focal length of the outgoing light beam so as to increase the distance between the convergence focal distance of the light in the first polarization state and the convergence focal distance of the light in the second polarization state;

A polarized light image sensor component is disposed on a side of the meta-lens away from the lens component to receive the light beam converged by the meta-lens.

In a second aspect, an embodiment of the present application provides an electronic device, including:

The lens module mentioned above.

In a third aspect, an embodiment of the present application proposes a depth of field extension method, which is applied to the above-mentioned depth of field extension device, and includes the following steps:

The incident light beam is converged by the lens assembly to form the outgoing light beam;

The outgoing light beam is converged by the meta-lens, so that the convergence focal distance of the first polarization state light is reduced and the convergence focal distance of the second polarization state light is increased;

The optical signals of the first polarization state light and the second polarization state light in the light beam converged by the meta-lens are identified, and the optical signals are converted into electrical signals.

In an embodiment of the present application, a metalens is used to adjust the focal length of an outgoing light beam so as to increase the distance between the convergence focal distance of light in the first polarization state and the convergence focal distance of light in the second polarization state; at the same time, a polarized light image sensor assembly is arranged on a side of the metalens away from the lens assembly to receive the light beam converged by the metalens, and is used to identify optical signals of the first polarization state light and the second polarization state light in the light beam converged by the metalens, and convert the optical signals into electrical signals, thereby achieving an extension of the depth of field. The metalens and the polarized light image sensor assembly have a simple structure and a small size, which meets the user's demand for thin and light electronic products and provides a good user experience.

Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

FIG1 is a schematic diagram of the structure of a lens module in the present application;

FIG2 is a schematic diagram of the structure of a meta-lens in a lens module of the present application;

FIG3 is an enlarged view of the detail structure at A in FIG2 ;

FIG4 is a schematic diagram of the adjustment of the first polarization state light and the second polarization state light by the meta-lens in the present application;

FIG5 is a schematic diagram of a polarizer in the present application collecting light signals entering an image sensor according to polarization states;

FIG6 is a flow chart of a depth of field extension method provided in an embodiment of the present application.

Reference numerals:

In the figure: 100, incident light beam; 200, outgoing light beam; 300, first polarized light; 400, second polarized light; 1011, first position; 1012, second position; 102, lens assembly; 103, image sensor; 104, depth of field range; 105, meta-lens; 106, polarizer; 1061, polarization unit; 107, sub-wavelength structure unit; 108, pixel unit; 109, signal processor; 10, polarized light sensor assembly.

Detailed ways

The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "multiple" means two or more. In addition, "and/or" in the specification and claims means at least one of the connected objects, and the character "/" generally means that the objects connected before and after are in an "or" relationship.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected 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 this application can be understood according to specific circumstances.

The lens module, electronic device and depth of field extension method according to the embodiments of the present application are described below in conjunction with Figures 1 to 6.

Referring to Figures 1 to 6, an embodiment of the present application provides a lens module that can better expand the depth of field range of electronic devices with camera functions such as mobile phones, cameras, personal game consoles, and tablet computers. Moreover, on this basis, it can optimize the structure of the electronic device, facilitate the lightweight design of electronic products, and provide users with comfort.

It should be noted that in the shooting structure of the prior art, the light beam passing through the lens module will produce an allowable circle of confusion on the image plane where the image sensor is located, and the allowable circle of confusion corresponds to the depth of field range in which a clear image can be formed before and after the object being photographed. This depth of field range is the depth of field range of the shooting structure in the prior art, and the depth of field range is relatively small. As the aperture of the shooting structure continues to increase, the depth of field of the lens module is also constantly shortening. Especially for the application of high-magnification microscopic optical photography, usually because the object distance is very short, the depth of field is relatively shallow, and the slightest movement on the object side will make the image blurred, greatly affecting the user experience.

The lens module provided in the embodiment of the present application can better solve the problem of small depth of field range of the above-mentioned shooting structure.

Specifically, as shown in FIG1 , the lens module includes:

The lens assembly 102 is used to converge the incident light beam 100 to form an outgoing light beam 200. The lens assembly 102 is used to converge the incident light beam 100.

The meta-lens 105 is disposed on a side of the lens assembly 102 away from the incident light beam 100, and is used to adjust the focal length of the outgoing light beam 200, so that the distance between the convergence focal distance of the first polarization state light 300 and the convergence focal distance of the second polarization state light 400 is increased. The meta-lens 105 is used to converge the outgoing light beam 200 again, and adjust the focal length of the outgoing light beam 200 during the convergence process, so that the distance between the convergence focal distance of the first polarization state light 300 and the convergence focal distance of the second polarization state light 400 is increased, thereby expanding the depth of field range 104 of the lens module.

The polarized light image sensor assembly 10 is arranged on a side of the meta-lens 105 away from the lens assembly 102 to receive the light beam after being converged by the meta-lens 105. The outgoing light beam 200 is received by the polarized light image sensor assembly 10 after being converged by the meta-lens 105. The polarized light image sensor assembly 10 is used to identify the optical signals of the first polarized light 300 and the second polarized light 400 in the light beam after being converged by the meta-lens 105, and convert the optical signals into electrical signals. That is, the meta-lens 105 exhibits a differentiated phase response according to the different polarization angles of the incident light beam 100, and the polarized light image sensor assembly 10 can complete the hierarchical screening process of the collected information to ultimately achieve the purpose of extending the depth of field.

In an embodiment of the present application, the metalens 105 is used to adjust the focal length of the outgoing light beam 200 so that the distance between the convergence focal distance of the first polarization state light 300 and the convergence focal distance of the second polarization state light 400 increases; at the same time, the polarized light image sensor component 10 is arranged on the side of the metalens 105 away from the lens component 102 to receive the light beam converged by the metalens 105, and is used to identify the optical signals of the first polarization state light 300 and the second polarization state light 400 in the light beam converged by the metalens 105, and convert the optical signals into electrical signals, thereby achieving an extension of the depth of field. The metalens 105 and the polarized light image sensor component 10 have a simple structure and a small size, which meets the user's demand for lightweight electronic products and provides a good user experience.

It should be noted that, as shown in FIG1 , the purpose of the lens module provided by the present application is to meet the user's experience requirements when taking photos and solve the problem of too shallow depth of field of the existing shooting structure. The basic principle of the lens module is: by adding a meta-lens 105 (metalens, referred to as ML) after the lens assembly 102, and then by reasonably designing the length and width of the sub-wavelength structure unit 107 of the meta-lens 105 according to the shooting needs, it is possible to focus a certain polarization component of the free polarized natural light (that is, the first polarization state light 300 and the second polarization state light 400) that cannot be focused within the focal depth of the lens module, thereby achieving the effect of expanding the depth of field. In the optical signal collection stage, the polarized light image sensor assembly 10 added after the meta-lens 105 can be collected according to the polarization state classification, and finally the image with enhanced depth of field is output through the signal processor 109.

For example, the meta-lens 105 can adopt nano-imprint technology, combined with semiconductor process technologies such as deposition and etching, to better realize low-cost and large-area meta-lens 105 processing, which is conducive to further reducing the processing cost of the depth of field extension device.

In addition, the incident light beam 100 is natural light, and the present application makes full use of the non-polarization characteristics of natural light, and does not require additional encoding of the incident light beam 100, which is simple to operate. The reason is that natural light is actually composed of many linearly polarized lights with different vibration directions.

For ease of explanation, in the present application, since the meta-lens 105 responds differently to orthogonal linear polarized light, additional focal length variables Δf1 and Δf2 are introduced on the basis of the focal length f of the original lens module, which is equivalent to strengthening or weakening the focusing ability of the original lens module, thereby achieving fine-tuning of the focal length to better expand the depth of field.

According to Malus's law, light of any polarization state can be expressed as the vector sum of s-polarized light and p-polarized light components. The polarization direction of s-polarized light is perpendicular to the polarization direction of p-polarized light. That is, the difference between the polarization angle of s-polarized light and the polarization angle of p-polarized light is 90°. The characteristic of the meta-lens 105 is that it can modulate the s-polarized light as a negative lens, so that the overall focal length of the depth of field extension device after the introduction of the meta-lens 105 is f+Δf1 (Δf1 is a negative number), and it can modulate the p-polarized light as a positive lens, so that the overall focal length of the depth of field extension device after the introduction of the meta-lens 105 is f+Δf2 (Δf2 is a positive number).

Referring to FIG. 2 and FIG. 3 , FIG. 2 is an overall schematic diagram of the meta-lens 105, and FIG. 3 is an enlarged diagram of the detailed structure at A in FIG. 2 . FIG. 3 is also an enlarged schematic diagram of a single subwavelength structural unit 107. The propagation direction of light is set to Z, and the polarization direction is usually decomposed into electric field components along the X-axis and along the Y-axis, corresponding to s-polarized light and p-polarized light, respectively, and can be represented and calculated by Jones vectors. When the height (H) and period (P) are constant, different equivalent refractive indices can be provided for s-polarized light and p-polarized light by regulating the length (L) and width (W) of the anisotropic dielectric subwavelength unit structure parameters. The sum of the phase delays along the fast axis and the slow axis will result in a phase profile that is sensitive to linear polarization, thereby realizing polarization multiplexing.

FIG4 shows that the meta-lens 105 exhibits the characteristics of a positive lens and a negative lens for incident light of p-polarized light and s-polarized light, respectively. For the two polarization modes, the required lens phase distribution is directly encoded into the structural unit at each spatial position, and the linearly polarized light directly presents this phase distribution through the propagation phase effect. Specifically, in order to verify the polarization multiplexing characteristics of the meta-lens 105 in this embodiment, a meta-lens 105 is designed. The focal length of the positive lens is designed to be Δf2=100 microns, and the focal length of the negative lens is designed to be Δf1=-100 microns.

Formula 1:

Formula 2:

Combined with Figure 4, Formula 1 and Formula 2 indicate the phase values φp and φs obtained by the structural unit at each spatial position, where λ is the wavelength, and x and y are the coordinate values of the sub-wavelength structural unit 107. Figure 4 shows the modulation effect of the meta-lens 105 on p-polarized light and s-polarized light. From the electric field distribution diagram in the xz plane obtained by simulation calculation, it can be clearly seen that the meta-lens 105 exhibits the characteristics of a positive lens and a negative lens respectively for the incident light.

Optionally, the polarized light image sensor assembly 10 includes a polarizer 106 and an image sensor 103, and the polarizer 106 is located between the metalens 105 and the image sensor 103.

In the above embodiment, the polarizer 106 and the image sensor 103 are separately arranged, which is convenient for the structural layout of the lens module on the one hand, and also convenient for the polarizer 106 to classify and collect the light signal entering the image sensor 103 according to the polarization state of the polarizer 106, so as to facilitate the image sensor 103 to identify the light signal, and to convert the light signal into an electrical signal, so as to facilitate the subsequent electrical signal processing. The electrical signal is processed by the signal processor 109 to finally output a picture with enhanced depth of field.

A polarizer 106 is added in front of the image sensor 103. The polarizer 106 can pre-divide the optical signal entering the image sensor 103 into M channels according to the polarization state, where M is the number of polarization states of the polarizer 106, so as to facilitate the recognition of the image sensor 103 and further achieve the purpose of extending the depth of field. The polarizer 106 is an independent optical element.

Optionally, the metalens 105 moves the convergence point of the first polarization state light 300 to a first position 1011 close to the metalens 105 , and moves the convergence point of the second polarization state light 400 to a second position 1012 far from the metalens 105 .

In the above embodiment, the meta-lens 105 moves the convergence point of the first polarized light 300 to the first position 1011 to bring the convergence point of the first polarized light 300 closer; and moves the convergence point of the second polarized light 400 to the second position 1012 to pull the convergence point of the second polarized light 400 farther away. The distance between the first position 1011 and the second position 1012 forms the focal depth range of the lens module of the present application. Obviously, the focal depth range of the lens module of the present application increases, and the focal depth range is positively correlated with the depth of field range 104, and the depth of field range 104 of the lens module of the present application also increases. Referring to FIG. 1 , the lens module of the present application enables the first polarized light 300 or the second polarized light 400 that was originally unable to be focused within the focal depth of the lens module to be focused within the focal depth of the lens module. Correspondingly, the depth of field range 104 of the lens module is well expanded.

Optionally, the first polarized light 300 is s-polarized light, the second polarized light 400 is p-polarized light, and after the outgoing light beam 200 passes through the metalens 105, the distance between the convergence distance of the s-polarized light and the convergence distance of the p-polarized light increases.

In the above embodiment, the distance between the convergence distance of s-polarized light and the convergence distance of p-polarized light is increased by the meta-lens 105, so as to better expand the focal depth range of the lens module. Correspondingly, the depth of field range 104 of the lens module is greatly expanded, so that slight movement on the object side will not cause image blur of the lens module, thereby greatly improving the user experience.

It should be noted that when light penetrates the surface of an optical component (such as a beamsplitter) at a non-perpendicular angle, the reflection and transmission characteristics are both polarization dependent. In this case, the coordinate system used is defined by the plane containing the input and reflected beams. If the polarization vector of the light is in this plane, it is called p-polarization, and if the polarization vector is perpendicular to the plane, it is called s-polarization. Any input polarization state can be expressed as the vector sum of the s and p components.

Light incident on the surface of a medium is absorbed and then reradiated by oscillating electric dipoles at the interface between the two media. The polarization of freely propagating light is always perpendicular to the direction in which the light is traveling, and the dipoles that produce the transmitted (refracted) light oscillate in the direction of polarization of that light. These same oscillating dipoles also produce reflected light. However, the dipoles do not radiate any energy in the direction of the dipole moment. If the refracted light is p-polarized and propagates exactly perpendicular to the direction in which the light is predicted to be specularly reflected, the dipoles point in the direction of specular reflection and therefore no light is reflected.

The Brewster angle is often called the "polarization angle" because light reflected from the surface at this angle is completely out of the plane of incidence ("s-polarization"). Thus, a glass plate or a stack of plates placed in a light beam at the Brewster angle can be used as a polarizer. The concept of polarization angle can be extended to that of the Brewster wave number to cover a planar interface between two linear bidisperse materials. In the case of reflection at the Brewster angle, the reflected and refracted light rays are perpendicular to each other.

Optionally, the metalens 105 moves the focusing point of the s-polarized light to a first position 1011 close to the metalens 105 , and moves the focusing point of the p-polarized light to a second position 1012 far from the metalens 105 .

In the above embodiment, the metalens 105 moves the convergence point of the s-polarized light to the first position 1011 close to the metalens 105, thereby bringing the convergence point of the s-polarized light closer; at the same time, the metalens 105 moves the convergence point of the s-polarized light to the second position 1012 far away from the metalens 105, so as to move the convergence point of the p-polarized light farther away, thereby increasing the depth of focus range of the lens module, and the depth of focus range is positively correlated with the depth of field range 104, so that the depth of field range 104 of the lens module of the present application is well expanded.

Optionally, the polarized light image sensor assembly 10 includes a polarizer 106 and an image sensor 103, wherein the polarizer 106 is located between the metalens 105 and the image sensor 103, and the polarizer 106 includes a first polarization unit 1061 and a second polarization unit 1062, wherein the first polarization unit 1061 is used to pass s-polarized light, and the second polarization unit 1062 is used to pass p-polarized light.

In the above embodiment, the first polarization unit 1061 is used to pass s-polarized light, and the second polarization unit 1062 is used to pass p-polarized light, so the type of polarization unit of the polarizer 106 corresponds to the polarization state of the outgoing light beam 200, so that the polarizer 106 can better classify and collect s-polarized light and p-polarized light. The light intensity is then recorded by the image sensor 103 to better convert the optical signal into an electrical signal.

That is, the polarizer 106 can identify the changes in the optical signals of the s-polarized light and the p-polarized light passing through the metalens 105 , and the image sensor 103 converts the optical signals into electrical signals.

Optionally, the polarization angle of the first polarization unit 1061 is 0°, and the polarization angle of the second polarization unit 1062 is 90°.

In the above embodiment, referring to FIG. 5 , the polarizer 106 may be composed of a first polarization unit 1061 and a second polarization unit 1062, that is, M=2. The polarization angle of the first polarization unit 1061 is 0°, which is the same as the polarization angle of s-polarized light and is only used to pass s-polarized light; and the polarization angle of the second polarization unit 1062 is 90°, which is the same as the polarization angle of s-polarized light and is only used to pass p-polarized waves. Thus, dual-channel recording of s-polarized light and p-polarized light is achieved to better distinguish s-polarized light from p-polarized light, so as to facilitate the image sensor 103 to identify the optical signal and convert the optical signal into an electrical signal. Finally, the image with enhanced depth of field is output through the signal processor 109.

Of course, the polarizer 106 may be composed of four polarization units, and different angle differences may be formed between adjacent polarization units, thereby realizing multi-channel recording of the first polarization state light 300 and the second polarization light, so as to better realize the recognition of the image sensor 103 .

Referring to FIG5 , the polarizer 106 is used to classify and collect the optical signals entering the image sensor 103 according to the polarization state. The polarizer 106 in FIG5 is composed of a first polarization unit 1061 with a polarization angle of 0° and a second polarization unit 1062 with a polarization angle of 90°, that is, M=2, to correspond to s-polarized light and p-polarized light. Other light rays whose polarization directions are at a certain angle to s-polarized light or p-polarized light can be decomposed into small linear polarized light in the s and p polarization directions according to vector decomposition, and their light intensity information will eventually be recorded by the calculation unit. Every four pixels of the image sensor 103 form a pixel element, and each pixel unit 108 corresponds to a polarization unit. The polarizer 106 is an independent optical element. After passing through the polarizer 106, all optical signals will be first divided into two categories according to the difference in polarization angles, and then the color filter will divide each type of optical signal into three-channel data of R, G, and B. Therefore, after adding the polarization classification function of the polarizer 106, the total number of data channels is 2×3=6, which is convenient for the recognition and processing of the image sensor 103.

Optionally, every N pixels of the image sensor 103 constitute a pixel unit 108. For example, a pixel unit 108 may be composed of three pixels, four pixels, or six pixels. The present application does not limit the number of pixels corresponding to the pixel unit 108. Moreover, the number of pixels of the pixel unit 108 is very common in the prior art and will not be described in detail here. Referring to FIG. 5 , one pixel unit 108 corresponds to four pixels.

Each pixel unit 108 corresponds to a polarization unit of the polarizer 106, and the polarizer 106 includes a first polarization unit 1061 and a second polarization unit 1062, wherein the first polarization unit 1061 is used to pass the first polarization state light 300, and the second polarization unit 1062 is used to pass the second polarization state light 400, and the difference between the polarization angle of the first polarization unit 1061 and the polarization angle of the second polarization unit 1062 matches the difference between the polarization angle of the first polarization state light 300 and the second polarization state light 400. In other words, the difference between the polarization angle of the first polarization unit 1061 and the polarization angle of the second polarization unit 1062 is the same as the difference between the polarization angle of the first polarization state light 300 and the second polarization state light 400.

In the above embodiment, one polarization unit corresponds to one pixel unit 108, so that the light intensity information can be well recorded. The first polarization unit 1061 is used to pass the first polarization state light 300, and the second polarization unit 1062 is used to pass the second polarization state light 400, and the difference between the polarization angle of the first polarization unit 1061 and the polarization angle of the second polarization unit 1062 matches the difference between the polarization angle of the first polarization state light 300 and the second polarization state light 400, so that the polarizer 106 can better identify and distinguish the first polarization state light 300 and the second polarization state light 400, so that the image sensor 103 can quickly and accurately convert the optical signal into an electrical signal.

Optionally, the image sensor 103 includes a color filter and a photodiode, the color filter is used to classify light signals according to their wavelengths, and the photodiode is used to convert light signals into electrical signals.

In the above embodiment, the light beam modulated by the metalens 105 is screened and classified according to the polarization angle by the polarizer 106, and then classified according to the wavelength by the color filter of the image sensor 103, and the light signal is converted into an electrical signal by the photodiode. Finally, the ISP image signal processor and the DSP digital signal processor complete the subsequent signal processing and image output, thereby facilitating the depth of field enhancement of the output image.

In the embodiment of the present application, the working flow chart of the lens module is as follows: the natural light transmitted from the photographed scene contains polarization states in all possible directions. The light focused by the lens assembly 102 passes through the meta-lens 105. By designing the length and width of the sub-wavelength structure unit 107 of the meta-lens 105 as required, the meta-lens 105 weakens the focus of the first polarization state light 300 and strengthens the focus of the second polarization state light 400, so that a certain polarization component of the free polarization natural light that could not be focused within the focal depth of the lens assembly 102 is focused within the focal depth of the original lens module. The light beam modulated by the meta-lens 105 is screened and classified according to polarization by the polarizer 106, and then classified according to wavelength by the color filter in the image sensor 103, and the optical signal is converted into an electrical signal by the photodiode, and finally the ISP image signal processor and the DSP digital signal processor complete the subsequent signal processing and image output.

In a second aspect, an embodiment of the present application provides an electronic device, including:

The lens module as described above.

The electronic device can be a mobile phone, a camera, a personal game console, a tablet computer, etc. It can better expand the depth of field range 104 of the electronic device, and also optimize the structure of the electronic device, so as to facilitate the thin and light design of the electronic device, provide users with more comfortable use and better user experience.

In a third aspect, as shown in FIG6 , an embodiment of the present application provides a depth of field extension method, which is applied to the above-mentioned lens module and includes the following steps:

S101, the incident light beam 100 is converged by the lens assembly 102 to form the outgoing light beam 200;

S102, the outgoing light beam 200 is converged by the metalens 105, so that the convergence focal distance of the first polarized light 300 is reduced, and the convergence focal distance of the second polarized light 400 is increased;

S103, identifying optical signals of the first polarization state light 300 and the second polarization state light 400 in the light beam converged by the metalens 105, and converting the optical signals into electrical signals.

In the above embodiment, the depth of field extension method can well extend the depth of field of the lens module. The first polarization state light 300 is reduced in focus by the meta-lens 105, and the second polarization state light 400 is increased in focus, thereby increasing the depth of field range of the lens module, thereby well increasing the depth of field range 104 of the lens module.

At the same time, the depth of field extension method can better identify the optical signals of the first polarization state light 300 and the second polarization state light 400 in the light beam after convergence by the meta-lens 105, and convert the optical signals into electrical signals. Finally, the image with enhanced depth of field is output through the signal processor 109.

Optionally, the step of “identifying optical signals of the first polarization state light 300 and the second polarization state light 400 in the light beam converged by the metalens 105, and converting the optical signals into electrical signals” includes:

The polarized light image sensor assembly 10 decomposes the light beam converged by the metalens 105 into a first polarized light 300 and a second polarized light 400 through the polarizer 106 , and classifies and collects the first polarized light 300 and the second polarized light 400 passing through the polarizer 106 .

The polarized light image sensor assembly 10 decomposes the light beam converged by the meta-lens 105 into a first polarized light 300 and a second polarized light 400 through a polarizer 106, including decomposing a light vector having a polarization direction different from that of the first polarized light 300 and the second polarized light 400 into the first polarized light 300 and the second polarized light 400.

In this embodiment, the first polarization state light 300 is s-polarized light, and the second polarization state light 400 is p-polarized light.

The polarized light image sensor assembly 10 divides the collected first polarized light 300 and second polarized light 400 into at least three data channels of RGB through the image sensor 103 to record the light intensity.

In the above embodiment, the first polarized light 300 and the second polarized light 400 can be better classified and collected by the polarizer 106, and then the collected first polarized light 300 and the second polarized light 400 are respectively divided into at least three RGB data channels for light intensity recording by the image sensor 103, thereby effectively converting the optical signal into an electrical signal, and finally outputting a picture with enhanced depth of field.

For example, the photo recorded by the image sensor 103 is three-channel data of R, G, and B. After adding the polarization classification function of the polarizer 106, the total number of data channels is 3×M, so that the image sensor 103 can better identify it.

Furthermore, the signal processor 109 (such as an ISP image signal processor and a DSP digital signal processor) needs to process the information of 3×M channels collected by the image sensor 103. The processing process is: first, M color images mixed with RGB information are restored through an interpolation algorithm, and then with the help of image clarity evaluation methods or convolutional neural networks, such as grayscale entropy method, histogram method, energy gradient function, deep learning, etc., finally output the depth of field enhanced effect image.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims (6)

1. A lens module, comprising:

A lens assembly, wherein the incident light beam is converged by the lens assembly to form an emergent light beam;

The super-structure lens is arranged on one side of the lens component, far away from the incident light beam, and is used for adjusting the focal length of the emergent light beam, so that the distance between the converging focal length of the light with the first polarization state and the converging focal length of the light with the second polarization state is increased;

A polarized light image sensor assembly disposed at a side of the super-structured lens remote from the lens assembly to receive the light beam converged by the super-structured lens;

The polarized light image sensor assembly comprises a polaroid and an image sensor, wherein the polaroid is positioned between the super-structure lens and the image sensor, and the polaroid and the image sensor are arranged separately;

the polarizer comprises a first polarization unit and a second polarization unit, wherein the first polarization unit is used for passing s polarized light, and the second polarization unit is used for passing p polarized light;

the super-constructor lens moves the converging focus of the s-polarized light to a first position proximate to the super-constructor lens while moving the converging focus of the p-polarized light to a second position distal to the super-constructor lens.

2. The lens module of claim 1, wherein the polarization angle of the first polarization unit is 0 ° and the polarization angle of the second polarization unit is 90 °.

3. The lens module as recited in claim 1, wherein,

Each N pixel points of the image sensor form a pixel unit, each pixel unit corresponds to one polarization unit of the polaroid, the polaroid comprises a first polarization unit and a second polarization unit, the first polarization unit is used for passing through the first polarized light, the second polarization unit is used for passing through the second polarized light, and the difference value between the polarization angle of the first polarization unit and the polarization angle of the second polarization unit is matched with the difference value between the polarization angles of the first polarized light and the second polarized light.

4. An electronic device, comprising:

a lens module as claimed in any one of claims 1 to 3.

5. A depth of field expansion method, applied to the lens module set according to any one of claims 1 to 3, comprising the steps of:

Converging the incident beam through the optic assembly to form the outgoing beam;

The outgoing beam is converged by the super-structure lens, so that the converging focal length of the light with the first polarization state is reduced, and the converging focal length of the light with the second polarization state is increased;

And identifying optical signals of the first polarized light and the second polarized light in the light beam converged by the super-structure lens, and converting the optical signals into electric signals.

6. The depth-of-field expansion method according to claim 5, wherein said step of recognizing optical signals of the first polarized light and the second polarized light in the light beam condensed by the super-lens and converting the optical signals into electrical signals comprises:

The polarized light image sensor component decomposes the light beam converged by the super-structure lens into first polarized light and second polarized light through a polaroid, and classifies and collects the first polarized light and the second polarized light passing through the polaroid;

the polarized light image sensor component respectively divides the collected first polarized light and the second polarized light into at least three RGB data channels for light intensity recording through an image sensor.