WO2019037723A1

WO2019037723A1 - Photosensor and terminal device

Info

Publication number: WO2019037723A1
Application number: PCT/CN2018/101582
Authority: WO
Inventors: 王辉; 魏文雄; 瞿高鹏; 郭伟
Original assignee: 华为技术有限公司
Priority date: 2017-08-22
Filing date: 2018-08-21
Publication date: 2019-02-28

Abstract

A photosensor (10) and a terminal device (100). The photosensor (10) comprises at least one photosensor sub-module. Each photosensor sub-module comprises a first photodetector (11), a second photodetector (12), a first linear polarizing plate (13), a second linear polarizing plate (14), a first phase delay film (151), and a second phase delay film (152). The first photodetector is for acquiring a light intensity of a first mixed light of a mixed light that has passed through the first phase delay film and the first linear polarizing plate, and the second photodetector is for acquiring a light intensity of a second mixed light of the mixed light that has passed through the second phase delay film and the second linear polarizing plate, wherein the mixed light comprises a first light beam (A) and a second light beam (B). After the mixed light passes through the second linear polarizing plate, a first light beam is filtered such that a difference between the light intensity of the first mixed light and the light intensity of the second mixed light is a light intensity of a light beam (A1) of the first light beam that has passed through the first phase delay film and the first linear polarizing plate.

Description

Light sensor and terminal equipment

The present application claims priority to Chinese Patent Application No. 201711083552.3, entitled "Optical Sensors and Terminal Equipment", which is filed on November 7, 2017, and the patent application number of 201711083552.3 is 2017. The priority of the Chinese Patent Application, which is hereby incorporated by reference in its entirety in the entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire all all all all all all each

Technical field

The present application relates to the field of optical sensors, and in particular, to a light sensor and a terminal device.

Background technique

In the current mobile phone or wearable device, in order to realize adaptive brightness adjustment of the screen according to the ambient light intensity, an ambient light sensor needs to be configured to realize light detection. With the simplification of the structure, the appearance and the like, it is necessary to place the light sensor on the back of the screen to achieve a full-screen display effect. That is to say, the ambient light sensor receives not only natural ambient light through a display such as an OLED screen, but also non-ambient light emitted by the display itself, such as non-polarized light, non-ambient light and through the display. The ambient light is simultaneously received by the underlying light sensor, causing light detection interference, resulting in the ambient light not being accurately detected.

Summary of the invention

The embodiment of the present application provides a light sensor for solving the problem that the ambient light cannot be accurately detected due to light detection interference existing in the prior art.

In a first aspect, the present application provides a light sensor including at least one light sensor sub-module, each of the light sensor sub-modules including a first photodetector, a second photodetector, a first linear polarizer, and a second linear polarization a first phase retardation film and a second phase retardation film; wherein the first photodetector and the second photodetector are disposed adjacent to each other; the first linear polarizer is located above the first photodetector; The second linear polarizer is located above the second photodetector, the first phase retardation film is located above the first linear polarizer, and the two phase retardation film is located above the second linear polarizer; a first photodetector is configured to obtain a light intensity of the first mixed light after the mixed light passes through the first phase retardation film and the first linear polarizing film, and the second photodetector is configured to acquire the mixed light passing through the The light intensity of the second phase retardation film and the second mixed light after the second linear polarizer, wherein the mixed light includes a first light and a second light, and the mixed light passes through the second linear polarizer , The first light is filtered such that a difference between a light intensity of the first mixed light and a light intensity of the second mixed light is that the first light passes through the first phase retardation film and the first linear polarization The light intensity of the light after the film. The light sensor can filter out other light than the natural ambient light, and avoid detecting the received interference, resulting in inaccurate detection results. The first phase retardation film and the second phase retardation film may be converted for circularly polarized light for the first light. Wherein, for stability, the first photodetector and the second photodetector may be connected to each other. In order to reduce the package volume of the photosensor and the sensing accuracy of the light, the first linear polarizer and the second linear polarizer are on the same level.

Wherein, the first phase retardation film and the second phase retardation film are integrally formed or separately formed. If the heights of the first photodetector and the second photodetector are the same in the vertical direction, the first phase retardation film and the second phase retardation film may be a complete diaphragm covering the first photodetector and the second light On the detector. If the first photodetector and the second photodetector are different in height, the first phase retardation film and the second phase retardation film may be respectively disposed, so that the first phase retardation film and the second phase are more flexibly disposed. The manner in which the retardation film is assembled with the first photodetector and the second photodetector, and the first phase retardation film and the second phase retardation film are integrally formed can reduce the processing flow.

The first light is circularly polarized light formed by ambient light passing through a display screen provided with a circular polarizing plate; the second light is light emitted by the display screen itself (such as light emitted from a self-illuminating pixel or backlight) Light from the lamp). The effect of ambient light outside the display on the brightness of the display can be detected by the light detector. It should be noted that, in the present application, "circular polarizing plate" refers to a device capable of converting unpolarized light into circularly polarized light, and its specific implementation form is not limited, for example, it can pass multiple discrete devices (such as The phase retardation film and the linearly polarizing plate are composed of a single device (such as a device in which a phase retardation film and a linear polarizing film are packaged, or a device that realizes the function by designing other structures).

The polarization direction of the first linear polarizing plate is consistent with the polarization direction of the first light ray before passing through the first linear polarizing plate, and the polarization direction of the first light ray is orthogonal to the second polarizing plate direction. In this way, a difference between the intensity of the light entering the first photodetector and the intensity of the second photodetector group can be made, and the intensity of the light to be detected can be obtained by the difference of the light intensities.

The first light is circularly polarized light, and the first light is converted into first linearly polarized light having the same polarization direction as the first linear polarizer by the first phase retardation film, the first Light passing through the second phase retardation film and then converted into second linearly polarized light orthogonal to a polarization direction of the second linear polarizer, such that the second linearly polarized light is filtered while passing through the second linear polarizer; The light is unpolarized light, and the second light passes through the first phase retardation film and then forms a third linearly polarized light through the first linear polarizer, and the second light passes through the second phase retardation film The second linear polarizer forms a fourth linearly polarized light, the first mixed light includes a first linearly polarized light and the third linearly polarized light, and the second mixed light includes the fourth linearly polarized light, wherein The light intensity of the three-line polarized light is the same as the light intensity of the fourth linearly polarized light, such that a difference between the first mixed light intensity and the second mixed light intensity is that the mixed light passes through the first phase Delay film and The light intensity of the first linearly polarized light obtained after the first linear polarizing plate; further, the light sensor can accurately detect the light intensity of the first light entering the light sensor, and avoid the influence of the second light on the detection .

The light sensor further includes a processor, the processor is configured to acquire a sum of strengths of the first light and the second light of the first photodetector, and a light intensity of the second light of the second photodetector And outputting a difference between the light intensity of the first photodetector and the light intensity detected by the second photodetector. The calculation of the sensed value of light is achieved by the processor to obtain the intensity of the light that needs to be detected. The processor is disposed in the first photodetector or the second photodetector, or is disposed on a circuit board of the optical sensor, and does not define a specific location, and may be combined with the actual space design of the photosensor; It can also be placed outside the light sensor, such as the processor of the terminal.

The photosensor sub-module is a plurality of and arranged in a matrix, and in a matrix formed by the plurality of photosensor sub-modules, the first photodetector and the second photodetector are staggered. The light intensity detected by the light sensor is the sum of the light intensities detected by the plurality of photosensor sub-modules, and is designed and arranged in combination with the actual requirements of the photosensor to achieve a better detection effect.

The present application provides a light sensor including at least one light sensor sub-module, each of the light sensor sub-modules including a first photodetector and a second photodetector disposed adjacent to the first photodetector; a linear polarizing plate positioned above the first photodetector; a second linear polarizing plate positioned above the second photodetector, the first photodetector for obtaining mixed light after passing through the first linear polarizing plate a first mixed light intensity, the second photodetector is configured to acquire a second mixed light intensity of the mixed light after passing through the second linear polarizing plate, wherein the mixed light includes a first light and a second light. The first light is linearly polarized light, the second light is unpolarized light, and the first light is polarized in the same direction as the first linear polarizer and orthogonal to the polarization direction of the second linear polarizer. The first light is filtered by the second linear polarizer, and the second light is converted into linearly polarized light after passing through the first linear polarizer and the second linear polarizer, such that the first mixed light intensity is Second mixed light The difference in intensity is the light intensity of the first light after passing through the first linear polarizer. The light sensor of the embodiment of the present application can directly detect the light intensity of the linearly polarized light entering the light sensor.

In a second aspect, the present application discloses a light sensor including at least one light sensor sub-module, each of the light sensor sub-modules of the present application includes a first photodetector, a second photodetector, a first linear polarizer, and a second line. a polarizing plate, a first phase retardation film, and a second phase retardation film, wherein:

The first photodetector of the present application is disposed adjacent to the second photodetector of the present application;

The first linear polarizing plate of the present application is located above the first photodetector of the present application;

The second linear polarizing plate of the present application is located above the second photodetector of the present application.

The first phase retardation film of the present application is located above the first linear polarizing plate of the present application;

The second phase retardation film of the present application is located above the second linear polarizing plate of the present application;

The first photodetector of the present application is used to obtain the light intensity of the first mixed light after the mixed light passes through the first phase retardation film of the present application and the first linear polarizing film of the present application. The second photodetector of the present application is used to obtain the mixed light of the present application. The light intensity of the second mixed light after passing through the second phase retardation film of the present application and the second linear polarizing film of the present application, wherein the mixed light of the present application includes the first light and the second light, and the mixed light of the present application is subjected to the second linear polarization of the present application. After the film is applied, the first light of the present application is filtered, so that the difference between the light intensity of the first mixed light of the present application and the light intensity of the second mixed light of the present application is that the first light of the application passes through the first phase retardation film of the present application and The light intensity of the light after applying the first linear polarizer.

In a first implementation manner of the second aspect, the fast axis direction of the first phase retardation film is consistent with the fast axis direction of the second phase retardation film; or the slow axis direction of the first phase retardation film is slower than the second phase retardation film The axes are in the same direction;

The polarization direction of the first linear polarizer coincides with the polarization direction of the first linearly polarized light obtained after the first light passes through the first phase retardation film, and the polarization direction of the first light is orthogonal to the polarization direction of the second polarizer.

In a second implementation of the second aspect, the fast axis direction of the first phase retardation film of the first phase retardation film is orthogonal to the fast axis direction of the second phase retardation film; or the first phase retardation of the first phase retardation film The slow axis direction of the film is orthogonal to the slow axis direction of the second phase retardation film;

The polarization direction of the first linear polarizer coincides with the polarization direction of the first linearly polarized light obtained after the first light passes through the first phase retardation film, and the polarization direction of the first light is consistent with the polarization direction of the second polarizer.

By the first and second implementations of the second aspect, the effect of filtering the first light mentioned in the second aspect can be achieved.

In a third implementation manner, the first light is a circularly polarized light formed by ambient light passing through a display screen provided with a circular polarizing plate;

The second light is the light emitted by the illumination assembly of the display. The light emitting component may be a self-illuminating pixel (such as a pixel of an OLED screen); or may be some backlight component, such as a backlight module (such as an LED) in an LCD screen; or other various components for emitting light.

Based on the second aspect and the various implementations of the second aspect, in the fourth implementation, the first phase retardation film is integrally formed with the second phase retardation film, or separately formed.

Based on the second aspect and the various implementations in the second aspect, in the fifth implementation, the first phase retardation film and the second phase retardation film are both quarter-wave plates.

Based on the second aspect and the various implementations in the second aspect, in the sixth implementation manner, the optical sensor sub-module is a plurality of and arranged in a matrix, and the first light is formed in a matrix formed by the plurality of optical sensor sub-modules The detector is interleaved with the second light detection.

In a seventh implementation manner, the light sensor further includes a processor, configured to acquire the intensity of the first light and the second light of the first photodetector. And, and the light intensity of the second light of the second photodetector, and outputting a difference between the light intensity of the first photodetector and the light intensity detected by the second photodetector.

Based on the second aspect and the various implementations in the second aspect, in the eighth implementation, the processor is disposed on one side or the bottom of the first photodetector or the second photodetector, or through a circuit board and light Sensor connection.

In a third aspect, the present application further discloses a light sensor including at least one light sensor sub-module, each of the light sensor sub-modules including a first photodetector, a second photodetector, a first linear polarizer, and a first a two-line polarizing plate, a first phase retardation film, and a second phase retardation film, wherein:

The first photodetector and the second photodetector are disposed adjacent to each other;

The first linear polarizing plate is located above the first photodetector;

The second linear polarizing plate is located above the second photodetector,

The first phase retardation film is located above the first linear polarizing plate;

The second phase retardation film is located above the second linear polarizing film;

The first photodetector is configured to acquire a light intensity of the first mixed light after the mixed light passes through the first phase retardation film and the first linear polarizing film, and the second photodetector is configured to acquire the mixed light a light intensity of the second mixed light after passing through the second phase retardation film and the second linear polarizing film;

Wherein the fast axis direction of the first phase retardation film of the first phase retardation film coincides with the fast axis direction of the second phase retardation film; or the first phase retardation of the first phase retardation film The slow axis direction of the film coincides with the slow axis direction of the second phase retardation film;

The polarization direction of the first linear polarizing plate is consistent with the polarization direction of the first light ray passing through the first phase retardation film, and the polarization direction of the first light ray is orthogonal to the polarization direction of the second polarizing plate. .

In a fourth aspect, the present application further discloses a light sensor, comprising: at least one light sensor sub-module, each of the light sensor sub-modules comprising a first photodetector, a second photodetector, a first linear polarizer, a second linear polarizing plate, a first phase retardation film, and a second phase retardation film, wherein:

The first linear polarizing plate is located above the first photodetector;

The second linear polarizing plate is located above the second photodetector,

a fast axis direction of the first phase retardation film of the first phase retardation film is orthogonal to a fast axis direction of the second phase retardation film; or the first phase retardation film of the first phase retardation film The slow axis direction is orthogonal to the slow axis direction of the second phase retardation film;

The polarization direction of the first linear polarizing plate is consistent with the polarization direction of the first linearly polarized light obtained by the first light ray passing through the first phase retardation film, and the polarization direction of the first light ray is opposite to the first The polarization directions of the two polarizers are the same.

For specific implementations of the third and fourth aspects, reference may be made to various implementations in the second aspect, and details are not described herein.

In a fifth aspect, the present application provides a terminal device, including a display screen, the display screen includes a phase retardation film, a linear polarizing film, and a transparent cover plate, and further includes the light sensor described in the above various aspects and various implementation manners. The mixed light is mixed with a first light formed by the ambient light passing through the display screen and a second light formed by the light of the display screen itself, and the light sensor outputs the light intensity of the ambient light to the terminal device to adjust the brightness of the display screen. The light sensor outputs the light intensity of the ambient light to the terminal device to adjust the brightness of the display screen, thereby ensuring the accuracy of the sensing, so that the display screen can correctly adjust the display light intensity. The terminal device can accurately detect the light intensity of the external ambient light through the light sensor, and avoid the influence of the light of the terminal device itself on the detection effect.

The light sensor further includes a processor, configured to acquire a sum of strengths of the first light and the second light of the first photodetector, and a light intensity of the second light of the second photodetector, and The difference between the light intensity of the first photodetector and the light intensity detected by the second photodetector is output. The calculation of the sensed value of light by the processor results in the intensity of the light that needs to be detected.

The terminal device includes a circuit board, the processor is disposed on the circuit board, or the processor is disposed in the optical sensor, and does not define a specific location, and is designed according to actual requirements.

In a sixth aspect, the present application provides a terminal device, including: a processor and a light sensor as provided in the foregoing aspects and various implementations, the processor for using the first mixed light intensity and the The light intensity of the two mixed lights is processed.

In an implementation manner, when the processor is configured to process the first mixed light intensity and the light intensity of the second mixed light, specifically, the first mixed light intensity and the first The light intensity of the two mixed lights is subtracted to obtain the light intensity of the light after the first light passes through the first phase retardation film and the first linear polarizing film.

The processor may be a CPU that performs a corresponding processing function by reading an instruction stored in the memory.

The light sensor described in the present application first converts ambient light and other interference light, that is, two different properties, into the same type of polarized light, and then obtains and generates a light intensity difference through the first photodetector and the second photodetector. The difference in light intensity is the desired light intensity converted by ambient light. In this way, the intensity of the light other than the natural ambient light acquired by the light sensor can be avoided and output, and the detection result is inaccurate without interference.

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background art, the drawings to be used in the embodiments of the present application or the background art will be described below.

1 is a side elevational view of an embodiment of a light sensor of the present application;

2A is a schematic diagram of light conversion and orientation of the optical sensor shown in FIG. 1;

2B is a schematic diagram of light conversion and direction of a photosensor according to another embodiment;

3 is a schematic view of another embodiment of the photosensor described in the present application;

4 is a schematic diagram of light conversion and direction of the optical sensor shown in FIG. 3;

FIG. 5 is a schematic diagram of a terminal device according to the present application; FIG.

6 is a schematic diagram of light conversion and trend of the terminal device shown in FIG. 5;

7 is a schematic diagram of a manner in which a processor is disposed in the optical sensor in the terminal device shown in FIG. 5;

Figure 8 is a schematic diagram of a matrix array of a plurality of photosensor sub-modules.

Detailed ways

The embodiments of the present application are described below in conjunction with the accompanying drawings in the embodiments of the present application.

In order to better illustrate the present application, some of the terms referred to in this application are explained below.

Unpolarized light: The light wave is a transverse wave, that is, the vibration direction of the light wave vector is perpendicular to the direction of light propagation. Generally, the light wave emitted by the light source has a random orientation of the light wave vector perpendicular to the direction of propagation of the light, but statistically, in all possible directions of space, the distribution of the light wave vector can be regarded as equal opportunity. Their sum is symmetric with the direction of light propagation, that is, the light vector has axial symmetry, uniform distribution, and the same amplitude of vibration in all directions. This is natural light, also called unpolarized light.

Linearly polarized light: The plane formed by the direction of vibration and the direction in which the light waves travel is called the vibrating surface. The vibrating surface of the light is limited to a certain fixed direction and is called linearly polarized light.

Circularly polarized light: The trajectory of the end point of the light vector is a circle, that is, the light vector continuously rotates, its size does not change, but the direction changes regularly with time.

Linear polarizer: Also called a linear polarizer, or a linear polarizer. The linear polarizer has a function of shielding (also can be understood as "filtering", "blocking") and transmission through the incident light, so that the longitudinal light or the lateral light can be transmitted, and the one is shielded (filtered or blocked). ). After passing natural light through a linear polarizer, only one direction of polarized light can pass through the device, and we get linearly polarized light.

Circularly polarized light: The circularly polarized light is composed of a linear polarizer and a λ/4 phase retardation film. Further, the polarization direction of the linear polarizer is 45 degrees with the O light (or E light) of the λ/4 phase retardation film.

Phase retardation film: also known as phase retardation diaphragm, phase retarder, or waveplate. It is machined from a material with birefringence that adjusts the polarization state of the beam. The wave plate has two mutually perpendicular optical axes (fast axis and slow axis). When the light passes through the wave plate, the light transmitted in a certain direction is faster. This direction is called the fast axis, corresponding to its vertical direction, the light The transmission speed is slow, called the slow axis.

When the polarization direction of the incident light is at an angle of 45 degrees to the fast axis direction of the wave plate, the light incident wave plate is decomposed into two beams of the same intensity and phase but the polarization direction is perpendicular, one beam is parallel to the fast axis, and one beam is parallel slow. The axis, because the transmission speed of the fast and slow axis light is different, the two beams will have a phase difference when passing through the wave plate. After passing, the two beams recombine a beam of light, but since the phases of the two beams are different, the new one The beam will also exhibit different polarization states. If the phase difference is 180°, the wave plate is called a 1/2 wave plate or a half wave plate, and the polarization direction of the outgoing light passing through the 1/2 wave plate is perpendicular to the polarization direction of the incident light.

In addition, when the phase difference is 90 degrees, the wave plate is called a quarter wave plate, and the light emitted by the 1/4 wave plate becomes circularly polarized light, and the circularly polarized light has no polarization direction. If the two quarter-wave plates are parallel to each other, they can form a 1/2-wave plate. It can be seen that the circularly polarized light is converted into linearly polarized light through a quarter-wave plate.

Referring to FIG. 1 , an optical sensor 10 is provided in the form of a chip on a hardware, and the chip can be directly installed under the display screen of an electronic device without placing It is below the special openings reserved outside the display area of the display screen. Therefore, the present embodiment can be applied to a full-display intelligent electronic device (ie, the display area of the front display of the device accounts for nearly 100%).

In this embodiment, the light sensor 10 receives light from ambient light through the display screen and light emitted by the display screen itself. It should be noted that when the received ambient light passes through the display screen, since the display screen is usually not transparent, there is a relatively large loss. In the process of going through the various types of optical devices (such as phase retardation film and linear polarizing film) to the photodetector, there will be losses, but the loss is almost small and negligible. The light lost through the display can be calibrated by the processor's post-compensation, so that the resulting light intensity matches the initial light intensity. The resulting light intensity is a standardized light intensity that can be adapted to more applications based on standardized light intensity. In another embodiment, calibration may not be required for a specific application, as long as the correspondence between the lost light intensity and a specific application is established, and subsequent processing may be performed based on the correspondence. For example, the screen brightness is associated with an uncalibrated light intensity that is ultimately detected directly by the light detector, and the screen is tuned to a particular brightness at a certain light intensity.

Specifically, the light sensor 10 includes at least one light sensor sub-module 10A, and each of the light sensor sub-modules 10A includes: a first photodetector 11, a second photodetector 12, a first linear polarizer 13, and a second linear polarizer 14. The first phase retardation film 151 and the second phase retardation film 152. The first photodetector 11 is disposed adjacent to the second photodetector 12. The first linear polarizer 13 is located above the first photodetector 11; the second linear polarizer 14 is located above the second photodetector 12. The first phase retardation film 151 is disposed above the first linear polarizing film 13, and the second phase retardation film 152 is disposed above the second linear polarizing film 14.

The first photodetector 11 is configured to acquire the first mixed light intensity after the mixed light passes through the first phase retardation film 151 and the first linear polarizing film 13, and the mixed light includes the first light A and the second light B. The second photodetector 12 is configured to obtain the light intensity of the second mixed light after the mixed light passes through the second phase retardation film 152 and the second linear polarizing film 14, and after the mixed light passes through the second linear polarizing film 14, the first light A is filtered. The difference between the first mixed light intensity and the second mixed light intensity is the light intensity of the first light A passing through the first phase retardation film 151 and the first linear polarizing film 13. The polarization direction of the first linear polarizing plate 13 coincides with the polarization direction of the first light ray A before passing through the first linear polarizing plate 13, and the polarization direction of the first light ray is orthogonal to the direction of the second polarizing plate 14.

The following takes an optical sensor sub-module 10A as an example for description. Specifically:

The first photodetector 11 and the second photodetector 12 may be located at the bottom of the chip in the direction of the receiving optical path, wherein the receiving optical path refers to an optical path that receives the light, that is, the light passes through the display screen from top to bottom. The optical path formed by the one-phase retardation film 151, the first linear polarizing plate 13, and the first photodetector 11 (or the light passes through the second phase retardation film 152, the second linear polarizing film 14, and the second photodetector in order from top to bottom The first linear polarizing plate 13 is stacked above the direction in which the first photodetector 11 receives the optical path. The first linear polarizing plate 13 and the second linear polarizing plate 14 are located on the same layer, that is, on the same horizontal plane. Of course, the height of the first linear polarizing plate 13 and the second linear polarizing plate 14 in the vertical direction is such that a height difference is allowed. For the sake of stability, the first photodetector 11 and the second photodetector 12 may be connected to each other in the horizontal direction. In the vertical direction, the heights of the first photodetector 11 and the second photodetector 12 are the same or some error is allowed. They are arranged separately in the horizontal direction and may or may not have a gap. The second light B obtained by the first photodetector 11 and the second light B obtained by the second photodetector 12 have the same light intensity. The intensity of light acquired by the first photodetector 11 and the second photodetector 12 produces a difference in intensity. The difference in intensity is the intensity of the light that you want to detect. In the embodiment of the present application, the first phase retardation film 151 and the second phase retardation film 152 are integrally formed, that is, a one-piece structure. Of course, the first phase retardation film 151 and the second phase retardation film 152 are separately laminated on the first linear polarizing film 13 and the second linear polarizing film 14, respectively.

In the present embodiment, the first phase retardation film 151 and the second phase retardation film 152 are λ/4 phase retardation films (or 1/4 wave plates), and the fast axis directions of the two phase retardation films are the same, therefore, When the circularly polarized light passing through the display passes through the two diaphragms, the two directions of polarized light (A1, A2) are polarized in the same direction.

2A is a light conversion and a trend diagram of the embodiment. This embodiment is an example of detecting the brightness of the light affected by the ambient light on the display screen by the light sensor. The ambient light of the unpolarized property passes through the display R to form a mixed light with the light inside the display screen (unpolarized light), which is the light that has passed through the display and does not enter the photodetector. The display screen is provided with a linear polarizer and a phase retardation film (also a λ/4 phase retardation film). The linear polarizer and the λ/4 phase retardation film in the display are combined to form a circular polarizer, which is not polarized. The ambient light enters the display screen (via the linear polarizer and the phase retardation film in the display screen) and is converted into circularly polarized light (A), that is to say, the mixed light includes the light of circular polarization property, that is, the first light A and the non- The light (light) of the polarization property is the second light B. The mixed light acquired by the first photodetector 11 and the second photodetector 12 is the same beam of the same property of the same brightness.

In this embodiment, the first light ray A of the circular polarization property is converted into the first linearly polarized light A1 having the same polarization direction as that of the first linear polarizer 13 through the first phase retardation film 151, and the first linearly polarized light A1 passes through the first The linear polarizing plate 13 has the same polarization property and is acquired by the first photodetector 11. At the same time, the first light A passes through the second phase retardation film 152 and is converted into the second linearly polarized light A2 orthogonal to the polarization direction of the second linear polarizing film 14. Since the linearly polarized light and the second linear polarizing plate 14 have orthogonal polarization directions, The second linearly polarized light A2 is filtered (or "masked", "blocked" when passing through the second linear polarizing plate 14, that is, the second linearly polarized light A2 cannot pass through the second linear polarizing plate 14); wherein the first linearly polarized light A1 and The second linearly polarized light A2 is the light after the first light A is converted into the polarization direction, and the light intensity is the same as the intensity when the first light A enters the light sensor, that is, the light intensity is constant before and after the conversion. The second light B is unpolarized light generated by the light emitted by the display itself (such as the light of the backlight or the light emitted by the self-luminous pixel), and the second light B does not undergo polarization conversion through the first phase retardation film 151, and then The first linear polarizer B1 is formed by the first linear polarizer B1, and is obtained by the first photodetector 11; the second ray B passes through the second phase retardation film 152 and then passes through the second linear polarizer 14 to form the fourth linearly polarized light B2. Acquired by the second photodetector 12; the first mixed light includes first linearly polarized light A1 and third linearly polarized light B1, and the second mixed light includes fourth linearly polarized light B2. Wherein, the light intensity of the third linearly polarized light B1 is the same as the light intensity of the fourth linearly polarized light B2, in fact, the light after the second light is converted into the polarized direction by the same light, and the light intensity is the same as the second light, that is, It is said that the light intensity is constant before and after the conversion, so that the difference between the first mixed light intensity and the second mixed light intensity is the first line obtained after the mixed light passes through the first phase retardation film 151 and the first linear polarizing film 13. The light intensity of polarized light A1.

The second photodetector 12 is configured to acquire the light intensity of the fourth linearly polarized light B2 converted by the unpolarized light through the second linear polarizing plate 14 without acquiring the second linearly polarized light A2 formed by the first light A conversion, because And the polarization direction of the second linearly polarized light A2 is orthogonal to the polarization direction of the second linear polarizing film 14. The first linearly polarized light A1 and the second linearly polarized light A2 are in the same phase, that is, the first linear polarizing plate 13 and the second linear polarizing plate 14 are orthogonal to each other.

The light sensor of the present application is used for detecting the light intensity of the ambient light in the outside world, and first converting the ambient light and other interference light, that is, two different properties, into the first mixed light and the second mixed light, and passes through the first light detector. 11 acquiring the first mixed light, the second photodetector 12 acquiring the second mixed light, causing the intensity of the light acquired by the second photodetector 12 of the first photodetector 11 to generate a difference in intensity, and then extracting the intensity difference by processing, It is the light intensity of the first light A converted by ambient light. In this way, the intensity of the light other than the natural ambient light acquired by the light sensor can be avoided and output, and the detection result is inaccurate without interference.

Referring to FIG. 2B, in another embodiment, the fast axis directions of the two phase retardation films (151, 152) may be orthogonal (vertical) to each other such that the first ray A (circularly polarized light) passes through two phases. After the retardation film (151, 152), the polarization directions of the two paths of polarized light A1 and A2 are orthogonal.

Accordingly, the polarization directions of the two linear polarizing plates (13, 14) are set to be the same at this time, and at the same time, orthogonal to the direction of one of the linearly polarized lights, so that one of the linearly polarized lights can be filtered out. For example, as shown in FIG. 2B, the polarization directions of the two linear polarizing plates (13, 14) are the same as those of the first linearly polarized light A1, so that since the second linearly polarized light A2 is orthogonal to the polarization direction of A1, A2 will It is filtered by the second linear polarizing plate 14. The remaining optical paths and corresponding processing can be referred to the description for FIG. 2A, and details are not described herein again.

As shown in FIG. 1 , the photo sensor further includes a processor 10B for acquiring the sum of the intensities of the first light A and the second light B detected by the first photodetector 11 and the second photodetector 12 The light intensity of the second light B, and the difference between the light intensity signal of the first light detector 11 and the light intensity signal detected by the second light detector 12, that is, the light intensity signal of the first light A, that is, after the conversion The light intensity of the first linearly polarized light A1. The processor 10B may be integrated in the light sensor at the side or the bottom of the first photodetector 11 and the second photodetector 12, and may be carried by a circuit board and associated with the first photodetector 11 and the second light. The detector 12 is connected. The processor 10B includes a reading module, a calculation module and an output module. The reading module reads the light intensity values of the first photodetector 11 and the second photodetector 12, and outputs the difference between the light intensity values to the calculation module. Output module output.

As shown in FIG. 8, the photosensor sub-module is a plurality of and arranged in a matrix, and in a matrix formed by a plurality of photosensor sub-modules, the first photodetector 11 and the second photodetector 12 are staggered. Multiple photosensor sub-modules may or may not be connected. As shown, each of the first photodetectors 11 is provided with a second photodetector 12 on one side thereof, and there are no two first photodetectors 11 or second rays continuously in the same horizontal or vertical row. Detector 12. The plurality of first photodetectors 11 and the plurality of second photodetectors 12 are arranged in a matrix. Of course, it is not limited to the arrangement of the embodiment, as long as the ambient light can be uniformly detected. The sensed light intensity of the photodetector is the sum of the light intensities of the first light A, that is, the ambient light, detected by the plurality of light sensor sub-modules.

Referring to FIG. 3 and FIG. 4 , in another embodiment of the present application, the first light A in the mixed light is linearly polarized light, and the first light A may be emitted from the unpolarized light through the light emitting body, such as a polarizing plate. The body is converted into a body, and the unpolarized light in this embodiment refers to natural ambient light such as sunlight. The second ray B is unpolarized light, such as light or unpolarized light of an unnatural environment. In the present embodiment, the first phase retardation film 151 and the second phase retardation film 152 are not required. The second light B is converted to form linearly polarized light after passing through the first linear polarizing plate 13 and the second linear polarizing film 14. Moreover, the linear ray polarization property of the second ray B after passing through the first linear polarizing plate 13 is unchanged, and the polarization direction of the second ray B passing through the second linear polarizing plate 14 and the polarization of the second ray B passing through the first linear polarizing plate 13 The directions are orthogonal. The first photodetector 11 acquires the light intensity of the first polarized light of the first light ray A passing through the first linear polarizing plate 13 and the third polarized light converted by the second light ray B through the first linear polarizing plate 11. The first light ray A is filtered out when passing through the second linear polarizing plate 14, and the second light detector 12 only acquires the light intensity of the second polarized light converted by the second light ray B through the second linear polarizing plate 14, the first light detector The light intensity value obtained by the first photodetector 11 and the second photodetector 12 produces a difference in intensity, and the output light intensity value is the intensity of the first light ray A1 passing through the first linear polarizing plate 11.

Referring to FIG. 5, the present application relates to a terminal device 100, which is a mobile phone, a tablet computer, or a wearable device having a screen. In this embodiment, a mobile phone is taken as an example. It includes a display screen 30, a processor 35 (for example, a CPU chip of a Qualcomm Snapdragon series, or a processor such as a chip of the Hess Kirin series) and a light sensor 10 disposed under the display screen 30, and the display screen 30 includes The laminated phase retardation film 31, the linear polarizing plate 32 and the transparent cover 33, the ambient light is converted into the first light A through the transparent cover 33, the linear polarizing plate 32, the phase retardation film 31 and the display screen 30, and the display screen 30 itself The emitted light is the second light B, and the first light A and the second light B are mixed light, which are detected by the light detector, and the processor 10B of the light sensor is used to acquire the first light and the first light detector 11 The sum of the intensities of the two rays, and the light intensity of the second rays of the second photodetector 12, and outputs the difference between the intensity of the light of the first photodetector and the intensity of the light detected by the second photodetector. The light sensor outputs the light intensity of the ambient light to the terminal device to adjust the brightness of the display.

The terminal device further includes a circuit board 36. The processor 35 is disposed on the circuit board 36. When the sensor 10 is packaged into a chip, the sensor chip can be implemented without the processor, and the processing function can be implemented by the processor 10, which can be considered as a mobile phone. The processor 35 logically has a function module 10B for specifically processing the data of the light sensor (for example, obtaining a light intensity value, performing calibration, etc.). Specifically, the processor 10 can pass a special hardware circuit (such as an FPGA or an ASIC). To realize the function of the 10B function module, or to implement the function of the 10B module in a software manner based on the general-purpose CPU core.

In another embodiment, as shown in FIG. 7, 10B may also be disposed inside the sensor chip, that is, the processing function module 10B is packaged together with other components of the sensor, and finally directly processed to the processor 35 of the terminal. result.

In this embodiment, the display screen is an OLED display (other types of displays, such as LED display screens, may also be used in other embodiments). The phase retardation film 31 is a phase retardation film having the same properties as the first phase retardation film 151 and the second phase retardation film 152. In the present embodiment, the phase retardation film 31 and the

phase retardation films

151 and 152 are both λ/4 phase retardation. membrane.

Referring to FIG. 6, when the screen of the mobile phone needs to adjust the brightness, the light sensor detects whether the light of the use environment is sufficient. When the ambient light passes through the display screen 30, the unpolarized light is converted into circularly polarized light, and the LED light of the display screen. Forming mixed light into the photosensor, replacing the first phase retardation film 151 with the second phase retardation film 152, the first linear polarizing film 13 and the second linear polarizing film 14, and finally being replaced by the first photodetector 11 and the second light The detector 12 acquires and produces a difference in light intensity, which is exactly the value of the light intensity of the ambient light. The processor further processes the light intensity difference output to the circuit board, removes the influence of the light, and performs reduction and calibration according to the overall transmittance of the OLED display to achieve moderate adjustment of the screen brightness. The light sensor used can be used to adjust the experience of the mobile phone or the wearable device to adjust the experience according to the ambient light.

One of ordinary skill in the art can understand that all or part of the process of implementing the above embodiment method (for example, calibrating data, performing specific operation such as adjusting light intensity based on the calibrated data) can be instructed by a computer program. The associated hardware is implemented, and the program can be stored in a computer readable storage medium, which, when executed, can include the flow of an embodiment of the methods described above. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

The present invention is further described in detail with reference to the preferred embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the present application are intended to be included within the scope of the present application.

Claims

A light sensor, comprising: at least one light sensor sub-module, each of the light sensor sub-modules comprising a first photodetector, a second photodetector, a first linear polarizer, a second linear polarizer, a phase retardation film and a second phase retardation film, wherein:

The first photodetector and the second photodetector are disposed adjacent to each other;

The first linear polarizing plate is located above the first photodetector;

The second linear polarizing plate is located above the second photodetector,

The first phase retardation film is located above the first linear polarizing plate;

The second phase retardation film is located above the second linear polarizing film;

The first photodetector is configured to acquire a light intensity of the first mixed light after the mixed light passes through the first phase retardation film and the first linear polarizing film, and the second photodetector is configured to acquire the mixed light a light intensity of the second mixed light after passing through the second phase retardation film and the second linear polarizer, wherein the mixed light includes a first light and a second light, and the mixed light passes through the second linear polarization After the slice, the first light is filtered.
The photosensor of claim 1 wherein:

a fast axis direction of the first phase retardation film of the first phase retardation film coincides with a fast axis direction of the second phase retardation film; or a first phase retardation film of the first phase retardation film The slow axis direction is consistent with the slow axis direction of the second phase retardation film;

The polarization direction of the first linear polarizing plate is consistent with the polarization direction of the first linearly polarized light obtained by the first light ray passing through the first phase retardation film, and the polarization direction of the first light ray is opposite to the first The polarization directions of the two polarizers are orthogonal.
The photosensor of claim 1 wherein:

a fast axis direction of the first phase retardation film of the first phase retardation film is orthogonal to a fast axis direction of the second phase retardation film; or the first phase retardation film of the first phase retardation film The slow axis direction is orthogonal to the slow axis direction of the second phase retardation film;

The polarization direction of the first linear polarizing plate is consistent with the polarization direction of the first linearly polarized light obtained by the first light ray passing through the first phase retardation film, and the polarization direction of the first light ray is opposite to the first The polarization directions of the two polarizers are the same.
The optical sensor according to any one of claims 1 to 3, wherein the first light is circularly polarized light formed by ambient light passing through a display screen provided with a circular polarizing plate;

The second light is light emitted by the light emitting component of the display screen.
The photosensor according to any one of claims 1 to 4, wherein the first phase retardation film is integrally molded with the second phase retardation film or separately formed.
A photosensor according to any one of claims 1 to 5, wherein:

Both the first phase retardation film and the second phase retardation film are quarter-wave plates.
The photosensor according to any one of claims 1 to 6, wherein the photosensor sub-module is a plurality of and arranged in a matrix, and the plurality of the photosensor sub-modules are formed in a matrix, the A photodetector is interleaved with the second photodetection.
The optical sensor according to any one of claims 1 to 7, wherein the photosensor further comprises a processor, wherein the processor is configured to acquire the first light and the second light of the first photodetector The sum of the intensities, and the light intensity of the second light of the second photodetector, and the difference between the light intensity of the first photodetector and the light intensity detected by the second photodetector.
The optical sensor according to claim 8, wherein the processor is disposed on one side or the bottom of the first photodetector or the second photodetector, or is connected to the photosensor through a circuit board.
A terminal device comprising a display screen comprising a phase retardation film, a linear polarizing plate and a transparent cover, characterized by further comprising the light sensor according to any one of claims 1-9, said mixing The light is mixed with the first light formed by the ambient light passing through the display screen and the second light formed by the light of the display screen itself, and the light sensor outputs the light intensity of the ambient light to the terminal device to adjust the brightness of the display screen.
The terminal device according to claim 10, wherein the light sensor further comprises a processor, wherein the processor is configured to acquire a sum of strengths of the first light and the second light of the first photodetector, and The light intensity of the second light of the second photodetector and the difference between the light intensity of the first photodetector and the light intensity detected by the second photodetector.
The terminal device according to claim 11, wherein the terminal device comprises a circuit board, the processor is disposed on the circuit board, or the processor is disposed in the light sensor.
The terminal device according to any one of claims 9 to 12, wherein said phase retardation film and said linear polarizing plate are for converting said ambient light into circularly polarized light by mutual cooperation as an input of said photosensor .
A terminal device, comprising: the light sensor according to any one of claims 1-9, a processor, wherein the processor is configured to light the first mixed light intensity and the second mixed light The strength is processed.
The terminal device according to claim 14, wherein the processor is configured to: when the first mixed light intensity and the second mixed light are processed, specifically for: The mixed light intensity and the light intensity of the second mixed light are subtracted to obtain a light intensity of the light after the first light passes through the first phase retardation film and the first linear polarizing film.