Polarization imaging device and electronic device

Abstract

The application provides a polarization imaging device and an electronic device, and relates to the technical field of biological identification. The polarization imaging device comprises a light source assembly, an optical element and a polarization imaging module arranged in sequence along an optical path. The optical element is arranged between a front camera and a camera opening on a display screen of the electronic device. The light source assembly, the optical element and the polarization imaging module are arranged on the same side of the display screen. The optical element has a reflecting surface for reflecting polarized light emitted by the light source assembly and transmitting visible light. The polarized light is reflected by the reflecting surface and a target object and then enters the polarization imaging module. The polarization imaging device adds the optical element between the front camera and the camera opening, so that the polarized light only passes through the display screen once during propagation, thereby effectively improving the accuracy of face recognition. The optical element is arranged by using the existing camera opening on the display screen, and no new opening or enlarged opening is needed, so that the visual experience of the user is not affected.

Description

Technical Field

[0001] This application relates to the field of biometric technology, and more specifically, to a polarization imaging device and electronic device. Background Technology

[0002] With the development of portable terminal devices, the application of biometric technology is becoming increasingly widespread and in-depth. Taking electronic devices as an example, fingerprint recognition and facial recognition are increasingly used in device screen wake-up and identity authentication steps in various programs, improving device security and the flexibility of usage.

[0003] Currently, the main solutions for facial recognition include binocular vision, time-of-flight, and structured light. Binocular vision's reconstruction accuracy is directly proportional to the camera's baseline length, limiting its application. Time-of-flight cameras are relatively expensive and limited by temporal resolution, resulting in low 3D imaging accuracy. While structured light offers high imaging accuracy, its slow response time and low frame rate, along with decreasing accuracy with increasing imaging distance, have led to the gradual development of polarized 3D imaging technology for facial recognition. However, this technology currently requires a separate hole in the display screen for the light beam to pass through, impacting the user's visual experience. Utility Model Content

[0004] The purpose of this application is to provide a polarization imaging device and electronic device in order to address the shortcomings of the prior art.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: One aspect of this application provides a polarization imaging device, including a light source assembly, an optical element, and a polarization imaging module arranged sequentially along an optical path. The optical element is disposed between a front-facing camera of an electronic device and a camera opening on the display screen of the electronic device. The light source assembly, the optical element, and the polarization imaging module are disposed on the same side of the display screen. The optical element has a reflective surface, which is used to reflect polarized light emitted by the light source assembly and transmit visible light. The polarized light is reflected by the reflective surface and the target object and then incident on the polarization imaging module.

[0006] Optionally, at least once the polarization direction of the polarized light emitted by the light source component is the same as the polarization direction of the polarization imaging module, and at least once the polarization direction of the polarized light emitted by the light source component is different from the polarization direction of the polarization imaging module.

[0007] Optionally, the light source assembly includes at least two light sources for emitting polarized light respectively, and the polarization imaging module includes an image sensor and a first polarization device. The polarization direction of the polarized light emitted by at least one light source is the same as the polarization direction of the first polarization device, and the polarization direction of the polarized light emitted by at least one light source is different from the polarization direction of the first polarization device. The polarized light reflected by the target object is modulated by the first polarization device and then directed towards the image sensor. Alternatively, the light source assembly includes a light source, and the light source includes at least two light-emitting areas for emitting polarized light respectively. The polarization imaging module includes an image sensor and a first polarization device. The polarization direction of the polarized light emitted by at least one light-emitting area is the same as the polarization direction of the first polarization device, and the polarization direction of the polarized light emitted by at least one light-emitting area is different from the polarization direction of the first polarization device. The polarized light reflected by the target object is modulated by the first polarization device and then directed towards the image sensor.

[0008] Optionally, the first polarizing device is a polarizer for the display screen.

[0009] Optionally, when the light source assembly includes at least two light sources for emitting polarized light respectively, the number of light sources is two, and the angle between the polarization directions of the polarized light emitted by the two light sources is 60° to 90°; when the light source assembly includes one light source, the number of light-emitting areas is two, and the angle between the polarization directions of the polarized light emitted by the two light-emitting areas is 60° to 90°.

[0010] Optionally, when the light source assembly includes at least two light sources for emitting polarized light respectively, the number of light sources is N, where N is an integer greater than or equal to 3, and the minimum angle between the polarization directions of the polarized light emitted by the two light sources is equal to 90° / (N-1); when the light source assembly includes one light source, the number of light-emitting areas is N, where N is an integer greater than or equal to 3, and the minimum angle between the polarization directions of the polarized light emitted by the two light-emitting areas is equal to 90° / (N-1).

[0011] Optionally, the light source assembly includes a light source for emitting polarized light, and the polarization imaging module includes an image sensor and at least two second polarization devices. The polarized light reflected from the target object is modulated by the second polarization devices and then directed toward the image sensor. The polarization direction of at least one second polarization device is the same as the polarization direction of the polarized light emitted by the light source, and the polarization direction of at least one second polarization device is different from the polarization direction of the polarized light emitted by the light source.

[0012] Optionally, the light-emitting direction of the light source component is towards the reflective surface of the optical element, and the light-incident direction of the polarization imaging module is towards the display screen. The polarized light emitted by the light source component is reflected by the reflective surface and then passes through the camera opening to the target object. After being reflected by the target object, it enters the polarization imaging module. Alternatively, the light-emitting direction of the light source component is towards the display screen, and the light-incident direction of the polarization imaging module is towards the reflective surface of the optical element. The polarized light emitted by the light source component passes through the display screen and then passes through the display screen to the target object. After being reflected by the target object, it passes through the camera opening to the reflective surface of the optical element. After being reflected by the reflective surface, it enters the polarization imaging module.

[0013] Optionally, the optical element also has a first light-transmitting surface and a second light-transmitting surface located on opposite sides of the reflective surface. Both the first and second light-transmitting surfaces are configured to be parallel to the display screen. The first light-transmitting surface is close to the camera opening, and the second light-transmitting surface is close to the front camera. The angle between the reflective surface and the first light-transmitting surface is 45°.

[0014] Optionally, the optical element includes a first prism and a second prism bonded to the first prism, wherein the surface of the first prism facing the camera opening is a first light-transmitting surface, the surface of the second prism facing the front camera is a second light-transmitting surface, and the bonded surface of the first prism or the second prism is a reflective surface.

[0015] In another aspect of the embodiments of this application, an electronic device is provided, including a device body and a polarization imaging device as described in any of the above. The polarization imaging device is disposed within the device body. The device body includes a display screen and a front-facing camera. The display screen has a camera opening corresponding to the position of the front-facing camera. The optical element of the polarization imaging device is located between the front-facing camera and the camera opening.

[0016] The beneficial effects of this application include: This application provides a polarization imaging device, including a light source assembly, an optical element, and a polarization imaging module arranged sequentially along the optical path. The optical element is positioned between the front-facing camera of an electronic device and the camera opening on the display screen of the electronic device. The light source assembly, optical element, and polarization imaging module are positioned on the same side of the display screen. The optical element has a reflective surface that reflects polarized light emitted by the light source assembly and transmits visible light. The polarized light is reflected by the reflective surface and the target object before entering the polarization imaging module. This polarization imaging device adds an optical element that changes the optical path between the light source assembly and the polarization imaging module, and positions the optical element between the front-facing camera and the camera opening. This ensures that the polarized light emitted by the light source assembly passes through the display screen only once during propagation, reducing the influence of the display screen on the polarized light and effectively improving the accuracy of face recognition. Moreover, the optical element utilizes the existing camera opening on the display screen of the electronic device, without adding a new opening to the display screen or enlarging the size of the existing camera opening. Therefore, it does not affect the user's visual experience. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is one of the schematic diagrams of the operation of the polarization imaging device provided in the embodiments of this application; Figure 2 This is the second schematic diagram of the operation of the polarization imaging device provided in the embodiments of this application; Figure 3 This is the third schematic diagram of the operation of the polarization imaging device provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of the optical element in the polarization imaging device provided in the embodiments of this application.

[0019] Icons: 11-Light source assembly; 111-Light source; 12-Optical element; 12a-First prism; 12b-Second prism; 121-Reflecting surface; 122-First light-transmitting surface; 123-Second light-transmitting surface; 13-Polarization imaging module; 131-Image sensor; 132-First polarization device; 133-Second polarization device; 20-Face; 31-Front-facing camera; 32-Display screen; 321-Camera opening; 41-Polarized light; 42-Visible light. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. It should be noted that, unless otherwise specified, the various features in the embodiments of this application can be combined with each other, and the combined embodiments are still within the protection scope of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] It should be understood that the target object in this application may be Figure 1 The face 20 in the text, and parts of the face 20 (such as cheeks, nose, and eyes), are not limited to these. They can also be other three-dimensional objects, such as fingers and palms. For ease of understanding, the face 20 will be used as an example in the following description. When the target object changes, those skilled in the art should be able to clearly understand the changed solution by referring to the following examples.

[0026] Please refer to Figure 1 One aspect of this application provides a polarization imaging device for installation within the main body of an electronic device. It acquires facial image information by emitting polarized light 41 towards a face 20 and receiving the reflected polarized light 41 from the face 20, facilitating facial recognition. Facial recognition includes face matching and / or anti-spoofing identification. Face matching refers to verifying whether the face 20 to be verified matches a pre-recorded correct face in a database (generally determined by similarity calculation). A correct face is also known as a face template or database image. Anti-spoofing identification refers to determining whether the face to be verified is a real face or a forgery such as a photo, video, or silicone face mold.

[0027] Specifically, the polarization imaging device includes a light source assembly 11, an optical element 12, and a polarization imaging module 13 arranged sequentially along the optical path. The optical element 12 is positioned between the front-facing camera 31 of the electronic device and the camera opening 321 on the display screen 32 of the electronic device, with the front-facing camera 31 and the camera opening 321 aligned. The light source assembly 11, the optical element 12, and the polarization imaging module 13 are located on the same side of the display screen 32.

[0028] The light source assembly 11 is used to emit polarized light 41. The optical element 12 has a reflective surface 121. The reflective surface 121 needs to have at least two functions: first, it can reflect the polarized light 41 emitted by the light source assembly 11; second, it can transmit visible light 42. The first function is to change the propagation path of the polarized light 41 so that the polarized light 41 can be smoothly emitted through the camera opening 321 or smoothly directed to the polarization imaging module 13, which will be described in detail later with reference to specific embodiments; the second function is to avoid the setting of the optical element 12 from affecting the front-facing camera function of the front-facing camera 31.

[0029] In order to distinguish between polarized light 41 and visible light 42, polarized light 41 can be selected as infrared polarized light. The wavelength range of infrared polarized light is different from that of visible light 42. In this way, by controlling the reflection spectrum range of the reflective surface 121 to be greater than or equal to the emission spectrum of the infrared light source, the imaging of the front camera 31 can be ensured without being affected while realizing the refracting of the infrared polarized light source.

[0030] The polarized light 41 emitted by the light source assembly 11 is reflected by the reflecting surface 121 and the target object before entering the polarization imaging module 13. It should be noted that the polarized light 41 can be reflected by the reflecting surface 121 first and then by the target object, or vice versa. After being reflected by the face 20, the polarized light 41 carries polarization information corresponding to the contour surface of the face 20. The image sensor 131 of the polarization imaging module 13 analyzes the polarization information carried in the polarization image to obtain the depth information of the face 20, thereby reconstructing the face contour surface and achieving face recognition.

[0031] The aforementioned polarization imaging device adds an optical element 12 to change the light path between the light source assembly 11 and the polarization imaging module 13. The optical element 12 is positioned between the front-facing camera 31 and the camera opening 321, ensuring that the polarized light 41 emitted by the light source assembly 11 passes through the display screen 32 only once during propagation. This reduces the influence of the display screen 32 on the polarized light 41 and effectively improves the accuracy of face recognition. Furthermore, the optical element 12 utilizes the existing camera opening 321 on the electronic device's display screen 32, without adding a new opening or enlarging the size of the existing camera opening 321. Therefore, it does not affect the user's visual experience.

[0032] Optionally, at least once the polarization direction of the polarized light 41 emitted by the light source assembly 11 is the same as the polarization direction of the polarization imaging module 13, and at least once the polarization direction of the polarized light 41 emitted by the light source assembly 11 is different from the polarization direction of the polarization imaging module 13. After being reflected by the reflective surface 121 and the target object, the polarized light 41 carries the polarization information corresponding to the contour surface of the target object and is incident on the polarization imaging module 13.

[0033] There are at least two scenarios: one is that the polarization direction of the polarization imaging module 13 remains unchanged, and the polarization direction of the polarized light 41 emitted by the light source component 11 changes at least twice, with at least one of the emitted polarized light 41 having the same polarization direction as the polarization imaging module 13, and at least one of the emitted polarized light 41 having a different polarization direction than the polarization imaging module 13; the other is that the polarization direction of the polarized light 41 emitted by the light source component 11 remains unchanged, the polarization imaging module 13 has at least two polarization directions, with one polarization direction of the polarization imaging module 13 having the same polarization direction as the polarized light 41 emitted by the light source component 11, and another polarization direction of the polarization imaging module 13 having a different polarization direction than the polarization direction of the polarized light 41 emitted by the light source component 11; or, a portion of the pixels of the polarization imaging module 13 can receive light with the same polarization direction as the polarized light 41, and a portion of the pixels can receive light with a different polarization direction than the polarized light 41. Of course, there are also cases where the polarization direction of the polarized light 41 emitted by the light source component 11 and the polarization direction of the polarization imaging module 13 both change, but controlling such cases is more complicated.

[0034] After being reflected by the face 20, the polarized light 41 carries polarization information corresponding to the contour surface of the face 20. The polarization information carried by the polarized light 41 with different polarization directions is different. Since the polarization direction of the polarized light 41 emitted by the light source component 11 and / or the polarization direction of the polarization imaging module 13 has changed at least twice, there are at least two polarized lights 41 with different polarization directions that eventually hit the image sensor 131 of the polarization imaging module 13. The image sensor 131 can obtain the depth information of the face 20 by analyzing the differences between the polarized images. Based on this, the face contour surface can be reconstructed more accurately, which helps to perform face recognition with higher accuracy.

[0035] Of course, the polarization direction of the polarized light 41 emitted by the light source component 11 in two or more consecutive phases can always be different from the polarization direction of the polarization imaging module 13. For example, the angle between the polarization direction of the polarized light 41 emitted by the light source component 11 in one phase and the polarization direction of the polarization imaging module 13 can be 5°, while the angle between the polarization direction of the polarized light 41 emitted in another phase and the polarization direction of the polarization imaging module 13 can be 95°. This can also improve the accuracy of face recognition.

[0036] Optionally, the light source assembly 11 includes at least two light sources 111 for emitting polarized light 41 respectively, and the at least two light sources 111 emit polarized light 41 sequentially at different time periods. The polarization imaging module 13 includes an image sensor 131 and a first polarization device 132. The polarized light 41 reflected by the target object is modulated by the first polarization device 132 and then directed towards the image sensor 131. Among the at least two light sources 111, at least one light source 111 emits polarized light 41 with the same polarization direction as the first polarization device 132, and at least one light source 111 emits polarized light 41 with a polarization direction different from the first polarization device 132.

[0037] This achieves the aforementioned goal that at least once the polarized light 41 emitted by the light source component 11 has the same polarization direction as the polarization imaging module 13, and at least once the polarized light 41 emitted by the light source component 11 has a different polarization direction than the polarization imaging module 13.

[0038] At this time, a feasible imaging process of the polarization imaging device is as follows: one light source 111 of the light source assembly 11 is lit to emit polarized light 41. The polarized light 41 is reflected by the optical element 12 and the face 20 and then enters the first polarization device 132. After being modulated by the first polarization device 132, it is received by the image sensor 131. The previous light source 111 is turned off, the next light source 111 is lit, and imaging is performed again until all light sources 111 have emitted light. The number of light sources 111 corresponds to the number of final imaging images. After processing all the imaging images by algorithm, the polarization signals corresponding to different parts of the face 20 can be extracted, and the anti-counterfeiting recognition of the face 20 can be completed.

[0039] Optionally, the light source assembly 11 also includes a housing, with at least two light sources 111 integrated within the same housing, so that the light source assembly 11 appears to emit light in different areas from the outside, and different areas emit light at different times.

[0040] Optionally, there are two light sources 111, and the angle between the polarization directions of the polarized light 41 emitted by the two light sources 111 is 60°~90°.

[0041] Setting the number of light sources 111 to two helps simplify the polarization imaging device and facilitates its miniaturization. At the same time, the polarized light 41 received by the polarization imaging module 13 corresponds to only two images, which also simplifies the number of images generated by the polarization imaging device and reduces the data processing load of the polarization imaging device.

[0042] The maximum angle between the polarization directions of the two polarized light beams 41 is 90°. When the angle is 90°, the accuracy of face recognition is highest; when the angle is between 60° and 90° (inclusive), the accuracy remains relatively high; and when the angle is less than 60°, the accuracy is low. Therefore, when there are two light sources 111, limiting the angle between the polarization directions of the polarized light 41 emitted by the two light sources 111 to 60°~90° can improve the face recognition accuracy of the polarization imaging device.

[0043] Of course, the number of light sources 111 can also be N, where N is an integer greater than or equal to 3. When the number of light sources 111 is N, the minimum angle between the polarization directions of the polarized light 41 emitted by any two light sources 111 is equal to 90° / (N-1).

[0044] For example, if there are three light sources 111, the polarization directions of the polarized light 41 emitted by the three light sources 111 are 0°, 45° and 90° respectively; or if there are four light sources 111, the polarization directions of the polarized light 41 emitted by the four light sources 111 are 0°, 30°, 60° and 90° respectively.

[0045] Optionally, the light source assembly 11 includes a light source 111, which includes at least two light-emitting areas. These at least two light-emitting areas sequentially emit polarized light 41 at different time intervals. The polarization imaging module 13 includes an image sensor 131 and a first polarization device 132. The polarized light 41 reflected from the target object is modulated by the first polarization device 132 and then directed towards the image sensor 131. Of the at least two light-emitting areas, at least one emits polarized light 41 with the same polarization direction as the first polarization device 132, and the polarization direction of the polarized light 41 emitted by at least one light-emitting area is different from the polarization direction of the first polarization device 132.

[0046] This scheme can also achieve the above-mentioned at least one instance where the polarized light 41 emitted by the light source component 11 has the same polarization direction as the polarization imaging module 13, and at least one instance where the polarized light 41 emitted by the light source component 11 has a different polarization direction than the polarization imaging module 13.

[0047] At this time, a feasible imaging process of the polarization imaging device is as follows: one light-emitting area of ​​the light source 111 is lit to emit polarized light 41. The polarized light 41 is reflected by the optical element 12 and the face 20 and then enters the first polarization device 132. After being modulated by the first polarization device 132, it is received by the image sensor 131. The previous light-emitting area is turned off, the next light-emitting area is lit, and imaging is performed again until all light-emitting areas are lit. The number of light-emitting areas corresponds to the final number of imaging images. After processing all the imaging images by algorithm, the polarization signals corresponding to different parts of the face 20 can be extracted, and the anti-counterfeiting recognition of the face 20 can be completed.

[0048] As mentioned earlier, when the angle between the polarization directions of the two polarized light beams 41 is between 60° and 90° (inclusive), the accuracy of face recognition remains at a high level. Therefore, when there are two luminous areas, limiting the angle between the polarization directions of the polarized light 41 emitted by the two luminous areas to 60°~90° can improve the face recognition accuracy of the polarization imaging device. When there are N luminous areas, where N is an integer greater than or equal to 3, the minimum angle between the polarization directions of the polarized light 41 emitted by any two luminous areas is equal to 90° / (N-1).

[0049] The first polarization device 132 in the polarization imaging module 13 can be an independent device located next to the display screen 32. In this case, the first polarization device 132 is located between the display screen 32 and the image sensor 131. The independent placement of the first polarization device 132 allows for more flexible parameter selection.

[0050] The first polarizing device 132 can also be a polarizer of the display screen 32. That is, the polarizer of the display screen 32 is used to modulate the polarization of the reflected polarized light 41, which can reduce the overall cost of the electronic device and save space.

[0051] Alternatively, please refer to Figure 3 The light source assembly 11 includes a light source 111 for emitting polarized light 41, the polarization direction of which remains unchanged. The polarization imaging module 13 includes an image sensor 131 and at least two second polarization devices 133, which operate at different times. The polarized light 41 reflected from the target object is modulated by the second polarization devices 133 and then directed towards the image sensor 131. At least one of the second polarization devices 133 has the same polarization direction as the polarized light 41 emitted by the light source 111, and at least one of the second polarization devices 133 has a different polarization direction than the polarized light emitted by the light source 111.

[0052] This also achieves the aforementioned goal that at least once the polarized light 41 emitted by the light source component 11 has the same polarization direction as the polarization imaging module 13, and at least once the polarized light 41 emitted by the light source component 11 has a different polarization direction than the polarization imaging module 13.

[0053] At this time, a feasible imaging process of the polarization imaging device is as follows: the light source 111 of the light source assembly 11 is lit to emit polarized light 41, and a second polarization device 133 is turned on. The polarized light 41 is reflected by the optical element 12 and the face 20 and then enters the turned-on second polarization device 133. After being modulated by the second polarization device 133, it is received by the image sensor 131. The previous second polarization device 133 is turned off, the next second polarization device 133 is turned on, and imaging is performed again until all second polarization devices 133 are turned on. The number of second polarization devices 133 corresponds to the final number of imaging images. After processing all the imaging images by algorithm, the polarization signals corresponding to different parts of the face 20 can be extracted, and the anti-counterfeiting recognition of the face 20 can be completed.

[0054] Another feasible imaging process of the polarization imaging device is as follows: the light source 111 of the light source assembly 11 is lit to emit polarized light 41. Different second polarization devices 133 that can pass through different polarization directions are set above different pixels of the image sensor 131. In one imaging process, some pixels can receive light with the same polarization direction as polarized light 41, while other pixels receive light with a different polarization direction than polarized light 41. The polarization signals corresponding to different parts of the face 20 are extracted by algorithm processing, and the anti-counterfeiting recognition of the face 20 is completed.

[0055] Optionally, please refer to again Figure 1 The light emitting direction of the light source component 11 is towards the reflective surface 121 of the optical element 12, and the light incident direction of the polarization imaging module 13 is towards the display screen 32. The polarized light 41 emitted by the light source component 11 is reflected by the reflective surface 121 and then passes through the camera opening 321 and is directed toward the target object. After being reflected by the target object, it is incident on the polarization imaging module 13.

[0056] The polarized light 41 emitted by the light source assembly 11 is reflected by the optical element 12 and exits through the camera opening 321 of the display screen 32 to the face 20. After being reflected by the face 20, it passes through the display screen 32 and is directed to the polarization imaging module 13. This arrangement allows the polarized light 41 emitted by the light source assembly 11 to directly reach the face 20 through the camera opening, avoiding passing through the display screen 32 at the initial end of the optical path. This reduces light loss and lowers the power consumption of the light source assembly 11. Furthermore, only the polarization imaging module 13 is affected by the display screen 32 when receiving light, thus achieving higher face recognition accuracy.

[0057] Alternatively, please refer to Figure 2The light emitting direction of the light source assembly 11 is towards the display screen 32, and the light incident direction of the polarization imaging module 13 is towards the reflective surface 121 of the optical element 12. The polarized light 41 emitted by the light source assembly 11 passes through the display screen 32 and is directed toward the target object. The polarized light 41 reflected by the target object is directed through the camera opening 321 toward the reflective surface 121 of the optical element 12, and after being reflected by the reflective surface 121, it is incident on the polarization imaging module 13.

[0058] Although the polarized light 41 emitted by the light source component 11 is affected by the polarizer of the display screen 32 before reaching the face 20, after being reflected by the face 20, it passes through the camera opening 321, passes through the display screen 32, and is then reflected by the optical element 12 to the polarization imaging module 13. Therefore, it is only affected by the display screen 32 once in the entire propagation path, thus achieving high face recognition accuracy.

[0059] The camera opening 321 of an electronic device is generally located at the upper edge of the display screen 32. Therefore, the space above the camera opening 321 inside the electronic device is relatively small, while the space below the camera opening 321 is relatively large. The volume of the light source assembly 11 of the polarization imaging device is smaller than that of the polarization imaging module 13. Therefore, optionally, the light source assembly 11 is located above the optical element 12, and the polarization imaging module 13 is located below the optical element 12.

[0060] That is, the light source component 11 is located in the space above the corresponding camera opening 321 inside the electronic device, and the polarization imaging module 13 is located in the space below the corresponding camera opening 321 inside the electronic device. This arrangement can make more reasonable use of the space inside the electronic device.

[0061] Alternatively, please refer to Figure 1 and Figure 4 The optical element 12 also has a first light-transmitting surface 122 and a second light-transmitting surface 123 located on opposite sides of the reflective surface 121. Both the first light-transmitting surface 122 and the second light-transmitting surface 123 are configured to be parallel to the display screen 32. The first light-transmitting surface 122 is close to the camera opening 321, and the second light-transmitting surface 123 is close to the front camera 31. The angle between the reflective surface 121 and the first light-transmitting surface 122 is 45°.

[0062] Natural light reflected from the face 20 passes sequentially through the camera opening 321, the first light-transmitting surface 122, the reflective surface 121, and the second light-transmitting surface 123 before entering the front-facing camera 31. The first light-transmitting surface 122, the reflective surface 121, and the second light-transmitting surface 123 can all transmit visible light 42, and the angles of the three surfaces are set to minimize the impact on visible light 42, ensuring that the added optical element 12 will not affect the normal operation of the front-facing camera 31.

[0063] Please refer to the reference. Figure 2,exist Figure 2 In the optical path, the above-mentioned limitations on the reflecting surface 121, the first light-transmitting surface 122, and the second light-transmitting surface 123 also apply.

[0064] Optionally, the optical element 12 includes a first prism 12a and a second prism 12b. Both the first prism 12a and the second prism 12b have adhesive surfaces and are bonded together through their respective adhesive surfaces. The surface of the first prism 12a facing the camera opening 321 is a first light-transmitting surface 122, and the surface of the second prism 12b facing the front camera 31 is a second light-transmitting surface 123. The adhesive surface of the first prism 12a or the second prism 12b is a reflective surface 121.

[0065] The first light-transmitting surface 122, the reflecting surface 121, and the second light-transmitting surface 123 can be obtained relatively easily by bonding the two prisms together. It is understood that in order to avoid the bonding affecting the propagation of polarized light 41 and visible light 42, the optical properties (such as refractive index, light transmittance, etc.) of the adhesive used must be matched with the materials of the first prism 12a and the second prism 12b.

[0066] The longitudinal sections of the first prism 12a and the second prism 12b can be selected as isosceles right triangles, and the dimensions of the longitudinal sections of the first prism 12a and the second prism 12b are equal.

[0067] Optionally, a reflective film is coated on the adhesive surface of the first prism 12a or the second prism 12b. The reflective film is used to reflect the polarized light 41 emitted by the light source 111 and transmit the visible light 42.

[0068] By coating the adhesive surface with a reflective film, it is relatively easy to make the adhesive surface reflect polarized light 41 and transmit visible light 42.

[0069] This embodiment also provides an electronic device, including a device body and a polarization imaging device as described above. The polarization imaging device is disposed within the device body. The device body includes a display screen 32 and a front-facing camera 31. The display screen 32 is provided with a camera opening 321 corresponding to the position of the front-facing camera 31. The optical element 12 of the polarization imaging device is located between the front-facing camera 31 and the camera opening 321.

[0070] The electronic device is a device with a front-facing camera 31 that requires facial recognition, such as a mobile phone, tablet computer, or laptop computer. This electronic device includes the same structure and beneficial effects as the polarization imaging device in the foregoing embodiments. The structure and beneficial effects of the polarization imaging device have been described in detail in the foregoing embodiments and will not be repeated here.

[0071] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A polarization imaging device, characterized in that, The device includes a light source assembly, an optical element, and a polarization imaging module arranged sequentially along the optical path. The optical element is disposed between the front-facing camera of the electronic device and the camera opening on the display screen of the electronic device. The light source assembly, the optical element, and the polarization imaging module are disposed on the same side of the display screen. The optical element has a reflective surface, which is used to reflect polarized light emitted by the light source assembly and transmit visible light. The polarized light is reflected by the reflective surface and the target object and then enters the polarization imaging module.

2. The polarization imaging device as described in claim 1, characterized in that, At least once, the polarization direction of the polarized light emitted by the light source component is the same as the polarization direction of the polarization imaging module, and at least once, the polarization direction of the polarized light emitted by the light source component is different from the polarization direction of the polarization imaging module.

3. The polarization imaging device as described in claim 1, characterized in that, The light source assembly includes at least two light sources for emitting polarized light respectively. The polarization imaging module includes an image sensor and a first polarization device. The polarization direction of the polarized light emitted by at least one of the light sources is the same as that of the first polarization device, and the polarization direction of the polarized light emitted by at least one of the light sources is different from that of the first polarization device. The polarized light reflected by the target object is modulated by the first polarization device and then directed towards the image sensor. Alternatively, the light source assembly includes a light source, the light source includes at least two light-emitting areas, the at least two light-emitting areas are used to emit polarized light respectively, the polarization imaging module includes an image sensor and a first polarization device, the polarization direction of the polarized light emitted by at least one of the light-emitting areas is the same as the polarization direction of the first polarization device, the polarization direction of the polarized light emitted by at least one of the light-emitting areas is different from the polarization direction of the first polarization device, and the polarized light reflected by the target object is modulated by the first polarization device and then directed towards the image sensor.

4. The polarization imaging device as described in claim 3, characterized in that, The first polarizing device is the polarizer of the display screen.

5. The polarization imaging device as described in claim 3, characterized in that, When the light source assembly includes at least two light sources for emitting polarized light respectively, the number of light sources is two, and the angle between the polarization directions of the polarized light emitted by the two light sources is 60°~90°. When the light source assembly includes a light source, the number of light-emitting areas is two, and the angle between the polarization directions of the polarized light emitted by the two light-emitting areas is 60°~90°.

6. The polarization imaging device as described in claim 3, characterized in that, When the light source assembly includes at least two light sources for emitting polarized light respectively, the number of light sources is N, where N is an integer greater than or equal to 3, and the minimum included angle between the polarization directions of the polarized light emitted by the two light sources is equal to 90° / (N-1). When the light source assembly includes a light source, the number of light-emitting areas is N, where N is an integer greater than or equal to 3, and the minimum angle between the polarization directions of the polarized light emitted from two light-emitting areas is equal to 90° / (N-1).

7. The polarization imaging device as described in claim 1, characterized in that, The light source assembly includes a light source for emitting polarized light, and the polarization imaging module includes an image sensor and at least two second polarization devices. The polarized light reflected by the target object is modulated by the second polarization devices and then directed toward the image sensor. The polarization direction of at least one second polarization device is the same as the polarization direction of the polarized light emitted by the light source, and the polarization direction of at least one second polarization device is different from the polarization direction of the polarized light emitted by the light source.

8. The polarization imaging device as described in claim 1, characterized in that, The light emission direction of the light source assembly is towards the reflective surface of the optical element, and the light incident direction of the polarization imaging module is towards the display screen. The polarized light emitted by the light source assembly is reflected by the reflective surface and then passes through the camera opening to the target object. After being reflected by the target object, it enters the polarization imaging module. Alternatively, the light emitting direction of the light source assembly is towards the display screen, and the light incident direction of the polarization imaging module is towards the reflective surface of the optical element. The polarized light emitted by the light source assembly passes through the display screen and is directed towards the target object. After being reflected by the target object, it passes through the camera opening and is directed towards the reflective surface of the optical element. After being reflected by the reflective surface, it is incident on the polarization imaging module.

9. The polarization imaging apparatus according to any one of claims 1 to 7, characterized in that, The optical element also has a first light-transmitting surface and a second light-transmitting surface located on opposite sides of the reflective surface. Both the first light-transmitting surface and the second light-transmitting surface are configured to be parallel to the display screen. The first light-transmitting surface is close to the camera opening, and the second light-transmitting surface is close to the front camera. The angle between the reflective surface and the first light-transmitting surface is 45°.

10. The polarization imaging device as described in claim 9, characterized in that, The optical element includes a first prism and a second prism bonded to the first prism. The surface of the first prism facing the camera opening is the first light-transmitting surface, and the surface of the second prism facing the front camera is the second light-transmitting surface. The bonded surface of the first prism or the second prism is a reflective surface.

11. An electronic device, characterized in that, The device includes a main body and a polarization imaging device as described in any one of claims 1 to 10, wherein the polarization imaging device is disposed within the main body, the main body includes a display screen and a front-facing camera, the display screen has a camera opening corresponding to the position of the front-facing camera, and the optical element of the polarization imaging device is located between the front-facing camera and the camera opening.

Images