CN104566212A - lens - Google Patents

Abstract

A lens comprises a bottom surface, a light incident surface used for receiving light rays, a light emergent surface arranged opposite to the light incident surface, and an optical axis penetrating through the light incident surface, wherein the light incident surface forms a reflecting surface at a position close to the bottom surface, the light rays deviating from the optical axis at a first angle enter the lens from the light incident surface and are emergent from the light emergent surface, the light rays deviating from the optical axis at a second angle are reflected by the reflecting surface and then enter the lens from the light incident surface and are emergent from the light emergent surface, and the second angle is larger than the first angle. Through the adjustment of the reflecting surface, the intensity of the central area of the light outlet of the lens is uniform, and the illumination requirement of the backlight module can be met.

Description

lens

technical field

The invention relates to a lens, in particular to an illuminating lens.

Background technique

As an emerging light source, light emitting diodes have been widely used in various applications, especially as a backlight module for displays. The existing backlight module is usually composed of a plurality of light emitting diodes arranged in an array, and the light emitted by each light emitting diode is mixed with each other to illuminate the display panel. However, since the illumination range of each light emitting diode is small, in order to illuminate a display panel with a large area, the backlight module needs to use a large number of light emitting diodes, resulting in high overall cost. Therefore, in order to reduce the number of LEDs used, LEDs are usually combined with lenses. The lens can diffuse the light emitted by the light-emitting diodes, so as to obtain a wider range of lighting effects. However, the light output of the existing lens is not uniform in the central region of the light pattern, especially the light intensity near the optical axis is quite different from the light intensity on the optical axis, resulting in an unsatisfactory overall light output.

Contents of the invention

Therefore, it is necessary to provide a lens with uniform light emission in the central area.

A lens, comprising a bottom surface, a light incident surface for receiving light, and a light exit surface opposite to the light incident surface, the lens has an optical axis passing through the light incident surface, and the light incident surface forms a reflective surface at a position close to the bottom surface, so as to The light that deviates from the optical axis at the first angle enters the lens from the light incident surface and exits from the light exit surface, and the light that deviates from the optical axis at the second angle is reflected by the reflective surface and then enters the lens from the light incident surface and exits from the light exit surface. greater than the first angle.

Since the lens has a reflective surface near the bottom surface of the light incident surface, it can reflect the light incident at a large angle, making it enter the lens from a position closer to the optical axis on the light incident surface, and then from the light exit surface. shoot out of the lens. As a result, this part of the light incident at a large angle is adjusted by the reflective surface and enters and exits the lens from a position closer to the optical axis, thereby increasing the light intensity near the optical axis of the lens and reducing the light intensity on the optical axis. The intensity difference between the light and the light near the optical axis makes the light in the central area of the lens light pattern more uniform.

The present invention will be further described below in conjunction with specific embodiments with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a perspective view of a lens according to an embodiment of the present invention.

FIG. 2 is an inverted view of the lens of FIG. 1 .

FIG. 3 is a cross-sectional view of the lens of FIG. 1 along line III-III.

Fig. 4 is similar to Fig. 3, where an LED is placed inside the lens.

FIG. 5 is a light pattern diagram of the lens of FIG. 1 .

Description of main component symbols

led 10 lens 20 cavity 200 reflective surface twenty one top edge 210 Bottom 212 bottom surface twenty two edge 222 Light incident surface twenty four part 240 part 242 light emitting surface 26 concave 262 Convex 264 side 28 light type 30

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

Detailed ways

Please refer to FIGS. 1 and 4 , which show a lens 20 according to an embodiment of the present invention, which is used to adjust the light of the LED 10 to form a desired light pattern.

The lens 20 is integrally formed of transparent materials, such as epoxy resin, silica gel, glass, and the like. The lens 20 is substantially circular as a whole, and includes a bottom surface 22 , a light incident surface 24 formed in the bottom surface 22 , a light exit surface 26 opposite to the bottom surface 22 , and a side surface 28 connecting the light exit surface 26 and the bottom surface 22 . The lens 20 also includes an optical axis O passing through the light emitting diode 10 , the center of the light incident surface 24 and the center of the light exit surface 2 .

Please refer to FIGS. 2-3 together. The bottom surface 22 of the lens 20 is circular, and a cavity 200 is formed at the center portion thereof. The cavity 200 is used for accommodating the LED 10 . A lower area of the inner wall of the cavity 200 forms a plurality of reflective surfaces 21 . In this embodiment, there are four reflective surfaces 21 arranged in the cavity 200 at regular intervals. Each reflective surface 21 is a plane perpendicular to the bottom surface 22 , which is defined by an arc-shaped top edge 210 and a straight bottom edge 212 . The bottom edge 212 of each reflective surface 21 is located in the bottom surface 22 of the lens 20 , and the top edge 210 is connected to the bottom edge 212 and is higher than the bottom edge 212 . The height of each reflective surface 21 is one third of the depth of the cavity 200 . The width of each reflective surface 21 gradually decreases from bottom to top, thereby forming a generally tongue-shaped structure. The four reflective surfaces 21 are arranged opposite to each other, and the bottoms 212 of two adjacent reflective surfaces 21 are connected by an arc-shaped edge 222 . The upper area and the lower area of the inner wall of the cavity 200 are located between the four reflective surfaces 21 and together form the light incident surface 24 of the lens. A part 240 of the light incident surface 24 is located above the four reflective surfaces 21 , and the other four parts 242 are respectively located between the four reflective surfaces 21 . The part 240 of the light incident surface 24 located above the four reflective surfaces 21 is an ellipsoid whose long axis is perpendicular to the bottom surface 22 and coincides with the optical axis O, and whose short axis is flush with the top of the reflective surface 21 . The portion 242 of the light incident surface 24 between every two adjacent reflective surfaces 21 is a concave arc surface whose width gradually increases from bottom to top and whose bottom width is smaller than that of each reflective surface 21 . Among the light emitted by the light emitting diode 10, the light that deviates from the optical axis O at a small angle will directly enter the lens 20 from the portion 240 of the light incident surface 24 of the lens 20, and a part of the light that deviates from the optical axis O at a large angle will be first reflected by the reflective surface 21. Reflected, and then enter the lens 20 from a position closer to the optical axis O on the part 240 of the light incident surface 24, another part of the light that deviates from the optical axis O at a large angle will directly pass from the part of the light incident surface 24 between the reflective surfaces 21 242 into the lens 20.

Please also refer to FIG. 5 , the light-emitting surface 26 of the lens is a free-form surface composed of a concave surface 262 and a convex surface 264 surrounding the concave surface 262 . The concave surface 262 is facing the light incident surface 24 , and its lowest point is aligned with the highest point of the light incident surface 24 . The convex surface 264 smoothly connects with the concave surface 262 . The bottom of the convex surface 264 is lower than the highest point of the light incident surface 24 . The light exit surface 26 is located at the top of the lens 20, and the light that exits at a small angle and enters directly from the portion 240 of the light entrance surface 24 will be positioned on and near the optical axis O after being diffused through the light exit surface 26; The light reflected by the reflective surface 21 into the lens 20 is still close to the optical axis O after being diffused by the light-emitting surface 26, thereby increasing the intensity near the optical axis O; exiting at a large angle and directly passing through the light-incident surface 24 is located between the reflective surfaces 21 The light in the portion 242 will be diffused by the light exit surface 26 and exit from a position away from the optical axis O. As a result, the light intensity difference on and near the optical axis O is reduced, so that the light in the central area of the light pattern 30 of the lens 20 is more uniform, so as to meet various lighting requirements, especially the lighting of the display backlight module. need.

The side surface 28 is perpendicular to the bottom surface 22 and connected to the light emitting surface 26 . In this embodiment, the side surface 28 is an annular surface connected to the bottom of the convex surface 264 of the light emitting surface 26 . The connection between the side surface 28 and the convex surface 264 forms a ridge-like structure. In other words, the connection between the side surface 28 and the convex surface 264 is not smooth. A very small portion of the light entering the lens 20 from the incident surface 24 can exit the lens 20 through the side surface 28 . Of course, by controlling the incident conditions of the light or the shape of the light incident surface 24, basically all the light entering the lens 20 from the light incident surface 24 can be emitted from the light exit surface 26, so as to obtain an ideal light exit effect.

Claims (10)

1. A lens, comprising a bottom surface, a light incident surface for receiving light, and a light exit surface opposite to the light incident surface, the lens also includes an optical axis passing through the light incident surface, characterized in that: the light incident surface is near the bottom surface A reflective surface is formed at the position, the light that deviates from the optical axis at the first angle enters the lens from the light incident surface and exits from the light exit surface, and the light that deviates from the optical axis at the second angle is reflected by the reflective surface and then enters the lens from the light incident surface and exits the lens. The second angle is greater than the first angle when the light emerges from the light-emitting surface. 2. The lens according to claim 1, characterized in that there are multiple reflective surfaces arranged at intervals from each other. 3. The lens as claimed in claim 2, wherein each reflective surface comprises a straight bottom and an arc-shaped top. 4. The lens according to claim 3, wherein the bottom of each reflective surface is located inside the bottom, and the bottoms of adjacent reflective surfaces are connected by arc-shaped edges. 5. The lens according to claim 2, wherein the width of each reflective surface gradually decreases from bottom to top. 6. The lens of claim 2, wherein each reflective surface is a plane perpendicular to the bottom surface. 7. The lens as claimed in claim 2, wherein the incident surface includes a portion above each reflective surface and a portion between each reflective surface. 8. The lens according to any one of claims 1 to 7, wherein the light exit surface comprises a concave surface and a convex surface surrounding the concave surface, and the concave surface is directly opposite to the light incident surface. 9. The lens according to any one of claims 1 to 7, further comprising a side surface connecting the convex surface and the bottom surface, and the side surface is perpendicular to the bottom surface. 10. The lens according to any one of claims 1 to 7, wherein a cavity is formed on the bottom surface of the lens, and the light incident surface and the light reflecting surface are located in the cavity.