WO2021142639A1

WO2021142639A1 - Sensor at lower part of display

Info

Publication number: WO2021142639A1
Application number: PCT/CN2020/072108
Authority: WO
Inventors: 闵丙日
Original assignee: 杭州芯格微电子有限公司
Priority date: 2020-01-15
Filing date: 2020-01-15
Publication date: 2021-07-22
Also published as: CN111868563A; CN111868563B

Abstract

A sensor (100) at the lower part of a display. The sensor (100) at the lower part of the display comprises: a light sensor (300), comprising a light-irradiating part (310), a first light-receiving part (320), and a second light-receiving part (330), wherein the light-irradiating part (310) irradiates sensing light used for sensing an object located outside of the display, and the first light-receiving part (320) and the second light-receiving part (330) detect external reflection light of the sensing light reflected back from the object and internal reflection light of the sensing light reflected inside of the display; a first sensor polarization layer (110) which is arranged on the upper part of the first light-receiving part (320) and has a polarization axis inclined at a first angle; a second sensor polarization layer (115) which is arranged on the upper part of the second light-receiving part (330) and has a polarization axis inclined at a second angle; and a sensor delay layer (120) which is arranged on the upper part of the sensor polarization layers and has a slow axis inclined at the first angle relative to the polarization axes.

Description

Sensor on the bottom of the display

Technical field

The present invention relates to a light sensor arranged in the lower part of a display.

Background technique

Light sensors are not only used in mobile electronic devices such as mobile phones and tablet computers, but also in video electronic devices such as televisions and monitors. The light sensor includes, for example, an illuminance sensor, a proximity sensor, and a proximity illuminance sensor. The proximity sensor is a light sensor that measures the distance between the user and the electronic device, and the illuminance sensor is a light sensor that senses the brightness of the periphery of the electronic device. The proximity illuminance sensor that combines an optical proximity sensor and an illuminance sensor realizes two sensors in a single package.

Recently, there has been an increase in the design of displays that occupy almost the entire front surface of electronic devices. Although the size of the display becomes larger according to the requirement for a large screen, it is still necessary to ensure at least a part of the front surface to configure the camera, especially close to the illuminance sensor. Proximity sensors using ultrasonic waves and the like can be applied to structures where the front surface is covered by a display, but it is difficult to integrate the function of sensing illuminance. On the other hand, although the illuminance sensor can also be located in an area other than the front surface, it may not be able to sense the surrounding light because of the casing used to protect the electronic device. Therefore, although the most ideal position where the proximity illuminance sensor can be installed is the front surface of the electronic device, in a design where the display occupies the entire front surface, it is difficult to secure a position where commonly used proximity illuminance sensors are arranged.

Summary of the invention

The object of the present invention is to provide an optical sensor that can be applied to an electronic device with a design that the display occupies the entire front surface.

An embodiment of the present invention provides a sensor in the lower part of a display, the sensor in the lower part of the display is arranged in the lower part of the display including a pixel that generates light, a display retardation layer arranged on the upper part of the pixel, and a display polarizing layer. The sensor at the lower part of the display may include: a light sensor, including a light irradiating part, a first light receiving part, and a second light receiving part, the light irradiating part irradiates sensing light for sensing objects located outside the display, the first The light-receiving part and the second light-receiving part detect the external reflection light of the induction light reflected from the object and the internal reflection light after the induction light is reflected inside the display; the first sensor polarizing layer is arranged on the first light receiving part The upper part of the part has a polarization axis inclined at a first angle; a second sensor polarization layer is arranged on the upper part of the second light receiving part and has a polarization axis inclined at a second angle; and the sensor retardation layer is arranged on The upper part of the sensor polarizing layer has a slow axis inclined at a first angle with respect to the polarizing axis. Wherein, the first sensor polarizing layer and the sensor retardation layer allow the external reflected light to pass through, and the internal reflected light to pass through with the blocking transmission ratio of the internal reflection, the second sensor polarizing layer and the The sensor retardation layer allows the blocking transmission ratio of the external light to pass through the external reflected light, and is capable of allowing the internal reflected light to pass.

According to an embodiment, the brightness of the external reflected light can be calculated using the blocking transmission ratio of the external light and the blocking transmission ratio of the internal reflection.

According to an embodiment, the first sensor polarizing layer and the sensor delay layer can convert the induced light into the sensor circularly polarized light so that the inductive sensor circularly polarized light can be delayed by the display through the display polarizing layer The layer is converted into linearly polarized light of the induction display having the same polarization axis as the polarization axis of the display polarization layer.

According to an embodiment, the slow axis of the sensor retardation layer may be parallel to the slow axis of the display retardation layer, and the polarization axis of the display polarizing layer may be inclined at a second angle with respect to the slow axis of the display retardation layer.

According to an embodiment, the difference between the second angle and the first angle may be 90 degrees.

Another embodiment of the present invention provides a sensor in the lower part of a display, the sensor in the lower part of the display is arranged in the lower part of the display including a pixel that generates light, a display retardation layer arranged on the upper part of the pixel, and a display polarizing layer. The sensor at the lower part of the display may include: a light sensor, including a light irradiating part, a first light receiving part, and a second light receiving part, the light irradiating part irradiates sensing light for sensing objects located outside the display, the first The light-receiving part and the second light-receiving part detect the external reflected light reflected by the sensing light from the object and the internal reflected light after the sensing light is reflected inside the display; the sensor polarizing layer is arranged on the upper part of the light sensor, It has a polarization axis inclined at a first angle; a first sensor retardation layer is arranged on the upper part of the sensor polarization layer corresponding to the first light-receiving part, and has a retarder that is inclined at a first angle with respect to the polarization axis. Axis; and a second sensor retardation layer, corresponding to the second light-receiving part, arranged on the upper part of the sensor polarizing layer, and having a slow axis inclined at a second angle with respect to the polarization axis. Wherein, the sensor polarizing layer and the first sensor delay layer allow the external reflected light to pass through, and the internal reflected light to pass through at the blocking transmission ratio of the internal reflection, the sensor polarizing layer and the second sensor The sensor retardation layer allows the blocking transmission ratio of the external light to pass through the external reflected light, and is capable of allowing the internal reflected light to pass.

According to an embodiment, the sensor polarizing layer and the first sensor delay layer can convert the induced light into the sensor circularly polarized light so that passing through the display polarizing layer, the inductive sensor circularly polarized light can be delayed by the display The layer is converted into linearly polarized light of the induction display having the same polarization axis as the polarization axis of the display polarization layer.

According to an embodiment, the slow axis of the first sensor retardation layer may be parallel to the slow axis of the display retardation layer, and the polarization axis of the display polarizing layer may be at a second angle relative to the slow axis of the display retardation layer. tilt.

According to an embodiment, the blocking transmission ratio of the external light may be measured in a state where the light irradiation part is closed, and the blocking transmission ratio of the internal reflection may be measured in a state without the external reflection light.

The illuminance sensor according to the embodiment of the present invention is suitable for an electronic device with a design that the display occupies the entire front surface.

Description of the drawings

Hereinafter, the present invention will be described with reference to the embodiments shown in the drawings. For ease of understanding, in all the drawings, the same constituent elements are denoted by the same reference numerals. The structure shown in the drawings is only an embodiment schematically shown for explaining the present invention, and does not limit the scope of the present invention. In particular, in order to facilitate the understanding of the invention, some constituent elements are shown somewhat exaggerated in the drawings. Since the drawings are for understanding the means of the invention, it should be understood that the width, thickness, etc. of the constituent elements shown in the drawings may vary in actual implementation.

FIG. 1 is a diagram for schematically explaining the structure of the sensor at the lower part of the display.

FIG. 2 is a diagram for schematically explaining the principle of measuring the blocking transmission ratio of external light.

Fig. 3 is a diagram for schematically explaining an embodiment of a sensor in the lower part of the display.

FIG. 4 is a diagram for schematically explaining when light irradiated from a sensor at the lower part of the display shown in FIG. 3 is reflected inside the display.

FIG. 5 is a diagram for schematically explaining another embodiment of the sensor in the lower part of the display.

FIG. 6 is a diagram for schematically explaining when light irradiated from a sensor at the lower part of the display shown in FIG. 5 is reflected inside the display.

FIG. 7 is a flowchart for schematically explaining the process of eliminating the influence based on internal reflection.

Detailed ways

The present invention can incorporate various modifications and can have various embodiments. Specific embodiments are shown in the drawings and described in detail. It should be understood that this does not limit the present invention to specific embodiments, but includes all modifications, equivalents, and alternatives that fall within the concept and technical scope of the present invention. In particular, the functions, features, and embodiments described below with reference to the drawings can be implemented alone or in combination with another embodiment. Therefore, it should be noted that the scope of the present invention is not limited to the manner shown in the drawings.

On the other hand, with regard to the terms used in this specification, expressions such as "substantially", "almost", "about", etc. are expressions that take into consideration allowable margins or possible errors in actual implementation. For example, "substantially 90 degrees" should be interpreted as including angles that can obtain the same effects as those at 90 degrees. For another example, "almost none" should be interpreted as including to the extent that even if there is a little, it can be ignored.

On the other hand, unless specifically mentioned, “side” or “horizontal” is used to indicate the left-right direction in the drawings, and “vertical” is used to indicate the up-down direction in the drawings. In addition, unless specifically defined, the angle, incident angle, etc. are based on a virtual straight line perpendicular to the horizontal plane shown in the drawing.

Hereinafter, in all the drawings, the hatching shown in the retardation layer indicates the direction of the slow axis, and the hatching shown in the polarizing layer schematically indicates the direction of the polarization axis with respect to the slow axis extending in parallel. On the other hand, it is shown that the slow axis of the display retardation layer and the slow axis of the sensor retardation layer both extend in the horizontal direction, or the slow axis of the display retardation layer and the slow axis of the sensor retardation layer extend in the vertical direction. This is simply expressed to facilitate understanding. It should be understood that it is not necessary to align the slow axis of the sensor retardation layer with the slow axis of the display retardation layer.

The sensor 100 at the lower part of the display includes a sensor polarizing layer 110, a sensor retardation layer 120, and a light sensor 300. The light sensor 300 functions as a proximity sensor, and for this purpose, it includes a light irradiating part 310 and a light receiving part 320. The light irradiating part 310 may be a light emitting diode that generates induced light 20 belonging to the visible light, near infrared, and infrared frequency bands. The light receiving unit 320 can detect reflected light belonging to visible light, near infrared, and infrared bands. For example, the light receiving unit 320 may be composed of a single photodiode, or may be composed of a plurality of photodiodes. In the case of being composed of a plurality of photodiodes, it can be divided into two or more regions, and the frequency band of light detected by each region may be different. To avoid interference, the light irradiating part 310 and the light receiving part 320 may be optically separated. Although not shown, a collimator lens for improving the straightness of the induced light may be disposed on the upper part of the light irradiation unit 310, and a condenser lens for condensing reflected light may be disposed on the upper part of the light receiving unit 320.

The sensor polarization layer 110 is disposed on the upper part of the photosensor 300 and has a polarization axis inclined at a first angle, for example, +45 degrees with respect to the slow axis of the sensor delay layer 120. The sensor delay layer 120 is disposed on the upper part of the sensor polarizing layer 110, and has, for example, a slow axis extending in the horizontal direction and a fast axis extending in the vertical direction. The slow axis of the sensor retardation layer 120 may be substantially parallel to the slow axis of the display retardation layer 12.

The sensor polarizing layer 110 and the sensor retardation layer 120 enable the induced light generated by the light irradiation unit 310 to pass through the display 10 to be emitted to the outside. In addition, the sensor polarization layer 110 and the sensor delay layer 120 allow the reflected light reflected by an external object to pass through the display 10 and reach the light receiving unit 320.

The light irradiating part 310 generates the induced light 20 which is non-polarized light. The generated induction light 20 becomes the induction sensor linearly polarized light 21 having a polarization axis inclined at a first angle as it passes through the sensor polarization layer 110. Since the polarization axis of the induction sensor linear polarization 21 is inclined at +45 degrees with respect to the slow axis of the sensor delay layer 120, the induction sensor linear polarization 21 passes through the sensor delay layer 120 and becomes an induction sensor circular polarization that rotates clockwise. twenty two. If the first polarized part of the linear polarized light 21 of the sensor sensor transmitted along the fast axis and the second polarized part of the linear polarized light 21 of the sensor sensor transmitted along the slow axis pass through the sensor delay layer 120, a λ/4 value will be generated between each other. Phase difference. The inductive sensor circularly polarized light 22 passes through the bottom surface of the display 10 and enters the inside of the display.

The inductive sensor circularly polarized light 22 becomes the inductive display linearly polarized light 23 as it passes through the display delay layer 12. Since the slow axis of the display retardation layer 12 is substantially parallel to the slow axis of the sensor retardation layer 120, the first and second polarized portions of the circularly polarized light 22 of the sensor sensor are increased by a λ/4 phase difference, so that the phase difference between each other is increased. Becomes λ/2. Thus, the polarization axis of the linear polarization 23 of the sensing display is rotated by about 90 degrees from the first angle and is inclined at a second angle, for example -45 degrees, with respect to the slow axis of the display retardation layer 12.

The linearly polarized light 23 of the sensor display passes through the display polarizing layer 11 and travels to the outside substantially without loss. The display polarizing layer 11 has a polarizing axis inclined at a second angle, for example -45 degrees, with respect to the slow axis of the display retardation layer 12. Therefore, the induction display linear polarization 23 having the polarization axis inclined at the same angle as the polarization axis of the display polarization layer 11 can pass through the display polarization layer 11.

The linearly polarized light 23 of the induction display emitted to the outside of the display 10 is reflected by the object and enters the display 10 again. In order to distinguish, the reflected light incident on the display 10 is referred to as a reflective display linearly polarized light 30. The reflective display linear polarizer 30 may have a polarization axis inclined at a second angle, for example -45 degrees. Therefore, the reflective display linear polarization 30 having the polarization axis inclined at the same angle as the polarization axis of the display polarization layer 11 can pass through the display polarization layer 11.

The reflective display linearly polarized light 30 passes through the display retardation layer 12 and becomes the reflective display circularly polarized light 31 that rotates in a counterclockwise direction. As described above, since the polarization axis of the display polarizing layer 11 is inclined at -45 with respect to the slow axis of the display retardation layer 12, a λ/4 phase is generated between the first polarized part and the second polarized part of the linear polarized light 30 of the reflective display. Difference. The reflective display circularly polarized light 31 passes through the bottom surface of the display 10 and is incident on the sensor 100 at the lower part of the display.

The circularly polarized light 31 of the reflective display passes through the sensor delay layer 120 to become the linearly polarized light 32 of the reflective sensor. As described above, since the slow axis of the display retardation layer 12 and the slow axis of the sensor retardation layer 120 are substantially parallel, the first and second polarized portions of the circularly polarized light 31 of the reflective display are increased by a λ/4 phase difference, thereby mutually The phase difference therebetween becomes λ/2. Thereby, the polarization axis of the reflective sensor linear polarization 32 is rotated from the second angle by about 90 degrees and is inclined at the first angle, for example +45 degrees, with respect to the slow axis of the sensor delay layer 120.

The reflective sensor linearly polarized light 32 travels through the sensor polarizing layer 110 to the light receiving section 320 substantially without loss. The sensor polarizing layer 110 may have a polarizing axis inclined at a first angle, for example +45 degrees, with respect to the slow axis of the sensor retardation layer 120. Therefore, the reflective sensor linear polarization 32 having the polarization axis inclined at the same angle as the polarization axis of the sensor polarization layer 110 can pass through the sensor polarization layer 110.

On the other hand, the light receiving unit 320 can not only detect the linearly polarized light 32 of the reflection sensor generated from the induced light 20 but also the linearly polarized light based on internal reflection. Linear polarization based on internal reflection can cause serious errors in the measurement value of the sensor at the bottom of the display. Therefore, in order to improve the accuracy of the sensor at the lower part of the display, it is necessary to correct the brightness detected by the light receiving unit 320.

The sensor 100 at the lower part of the display is arranged at the lower part of the display 10. The display 10 includes a pixel layer 13 in which a plurality of pixels P that generate light are formed, a display polarizing layer 11 and a display retardation layer 12 laminated on top of the pixel layer 13. In order to protect the display polarizing layer 11, the display retardation layer 12, and the pixel layer 13, a protective layer formed of an opaque material such as metal or synthetic resin may be disposed on the bottom surface of the display 10. As an example, the sensor 100 at the lower part of the display composed of the first sensor polarizing layer 110, the second sensor polarizing layer 115, the sensor retardation layer 120, and the photosensor 300 can be arranged in an area where a part of the protective layer is removed (hereinafter referred to as Complete structure). As another embodiment, the first sensor polarizing layer 110, the second sensor polarizing layer 115, and the sensor retardation layer 120 may be manufactured into a film shape and laminated on the bottom surface of the display 10. The sensor at the lower part of the display can be realized by attaching the photosensor 300 to the bottom surfaces of the first sensor polarizing layer 110 and the second sensor polarizing layer 115 (hereinafter referred to as an assembled structure). In the following, in order to avoid repetitive description, the description is centered on the completed structure.

The display polarizing layer 11 and the display retardation layer 12 improve the visibility of the display 10. The external light 14 incident through the upper surface of the display 10 is unpolarized light. If the external light 14 is incident on the upper surface of the display polarizing layer 11, only the light substantially consistent with the polarization axis of the display polarizing layer 11 passes through the display polarizing layer 11. The light passing through the display polarizing layer 11 is referred to as the display linearly polarized light 15 generated by external light. If the display linearly polarized light 15 generated by external light passes through the display retardation layer 12, it becomes the display circularly polarized light 16 (or elliptical polarization) generated by the external light rotating in the clockwise or counterclockwise direction. If the display circularly polarized light 16 generated by external light is reflected by the pixel layer 13 and is incident on the display retardation layer 12 again, it becomes linearly polarized light. Here, if the polarization axis of the display retardation layer 12 is inclined by about 45 degrees with respect to the slow axis, the polarization axis of the linear polarization of the second display and the polarization axis of the second linear polarization are orthogonal to each other. As a result, the linearly polarized light reflected by the pixel layer 13, that is, external light is blocked by the display polarizing layer 11 and cannot be emitted to the outside of the display. As a result, the visibility of the display 10 can be improved.

The sensor 100 at the lower part of the display includes: a first sensor polarizing layer 110, a second sensor polarizing layer 115, and a sensor delay layer 120 forming two light paths; and a light sensor 300 that detects light passing through each light path. The photosensor 300 includes a light irradiating part 310, a first light receiving part 320, and a second light receiving part 330.

The sensor delay layer 120 is arranged on the upper part of the first sensor polarizing layer 110 and the second sensor polarizing layer 115, and the photosensor 300 is arranged on the lower part of the first sensor polarizing layer 110 and the second sensor polarizing layer 115. The light irradiating part 310 and the first light receiving part 320 of the photosensor 300 are arranged under the first sensor polarization layer 110, and the second light receiving part 330 is arranged under the second sensor polarization layer 115. As an embodiment, the sensor retardation layer 120 may be laminated (laminated) on the upper surfaces of the first sensor polarizing layer 110 and the second sensor polarizing layer 115. The laminated sensor delay layer 120-the first and second

sensor polarizing layers

110 and 115 may be attached to the bottom surface of the display 10. The photosensor 300 may be attached to the bottom surfaces of the first sensor polarizing layer 110 and the second sensor polarizing layer 115. As another embodiment, the light sensor 300 may be realized by a thin film transistor. Thus, the sensor 100 in the lower part of the display can be manufactured by laminating the film-shaped sensor retardation layer 120, the first sensor polarizing layer 110, the second sensor polarizing layer 115, and the photosensor 300.

The polarization axis of the first sensor polarization layer 110 and the polarization axis of the second sensor polarization layer 115 are inclined at different angles with respect to the slow axis of the sensor delay layer 120. The polarization axis of the first sensor polarizing layer 110 may be inclined at a first angle, for example +45 degrees, with respect to the slow axis of the sensor retardation layer 120, and the polarization axis of the second sensor polarizing layer 115 may be at a first angle relative to the slow axis of the sensor retardation layer 120. Two angles such as -45 degrees inclination.

The light incident on the sensor 100 at the lower part of the display is the display circularly polarized light 16 generated by external light. The display circularly polarized light 16 generated by the external light becomes the sensor linearly polarized light 17 generated by the external light as it passes through the sensor delay layer 120. The sensor linearly polarized light 17 generated by external light becomes the sensor linearly polarized light 18 generated by the first external light as it passes through the first sensor polarization layer 110, and becomes the second external light generated by the second external light as it passes through the second sensor polarization layer 115 The sensor is linearly polarized 19.

The sensor delay layer 120-the first sensor polarizing layer 110 form a first light path, and the sensor delay layer 120-the second sensor polarizing layer 115 form a second light path. The first light path and the second light path function in different ways for the display circularly polarized light 16 generated by external light. The first light path passes the display circularly polarized light 16 generated by external light. On the contrary, the second light path blocks most of the circularly polarized light 16 of the display generated by external light and only passes a part of it. The first light path and the second light path are the same as the external light 14 for the induced light 20 after being reflected by an external object. Pass (first light path) and block it (second light path). The details are described below.

_{A proportional relationship of 1: K 1} is established between the sensor linear polarization 18 generated by the first external light and the sensor linear polarization 19 generated by the second external light: K 1 (where K ₁ <1). Here, K ₁ is the blocking transmission ratio of external light. Since the sensor linear polarization 18 generated by the first external light and the sensor linear polarization 19 generated by the second external light are both generated from the display circular polarization 16 generated by the same external light, only the light path is different, so there is a difference between the two The brightness is linear or non-linear. The non-linear proportional relationship may be caused by various reasons such as the structural characteristics of the display 10 and the wavelength range of the external light 14. The proportional relationship between the sensor linear polarization 18 generated by the first external light and the sensor linear polarization 19 generated by the second external light is 1: K ₁ can be substantially applied to the sensing light 20 as well. _{That is, the same proportional relationship 1: K 1} can be established between the brightness of the reflected induced light measured by the first light receiving unit 320 and the brightness of the reflected induced light measured by the second light receiving unit 330.

The first light path and the second light path can be next to each other or separate. That is, the first sensor polarizing layer 110 and the second sensor polarizing layer 115 are disposed under the single sensor delay layer 120, and the first light receiving portion 320 and the second light receiving portion 330 may be formed on the single photosensor 300. On the other hand, the second light receiving part 330 may be formed on another light sensor separate from the first light receiving part 320. A retardation layer (not shown) having a slow axis extending parallel to the slow axis of the sensor retardation layer and the second sensor polarizing layer 115 may be arranged on the upper portion of the second light receiving part 330.

Fig. 3 is a diagram for schematically explaining the operation of a sensor at the lower part of the display shown in Fig. 2. Since the process until the induced light 20 reaches the external object is similar to that of FIG. 1, the process of returning the reflected light to the sensor 100 at the lower part of the display will be described. Here, the description is made assuming that there is no internal reflection.

The linearly polarized light 23 of the induction display emitted to the outside of the display 10 is reflected by the object and enters the display 10 again. In a general use environment, not only the linearly polarized light 23 of the display, but also the external light 14 is incident on the display 10. Therefore, the incident display linearly polarized light 40, 40' is composed of the non-polarized external light 14 which passes through the display polarizing layer 11 and the reflective display linearly polarized light 30, 30'. The brightness of the external light 14 is much larger and constant than the brightness of the linearly polarized light 30, 30' of the reflective display. Therefore, the direct current offset (DC offset) of the pixel current can be used to represent the influence of the external light 14. In the non-polarized external light 14, since light having the same polarization axis as that of the display polarizing layer 11 passes through and light having other polarization axes is blocked, the brightness is reduced. Therefore, the brightness of the linearly polarized light 40, 40' of the incident display is relatively greater than the brightness of the linearly polarized light 30 of the reflective display.

The incident display linearly polarized lights 40, 40' pass through the display retardation layer 12 and become incident display circularly polarized lights 41, 41' rotating in the counterclockwise direction. As described above, since the polarization axis of the display polarizing layer 11 is inclined at -45 degrees with respect to the slow axis of the display retardation layer 12, λ is generated between the first polarized part and the second polarized part of the linearly polarized light 40, 40' incident on the display. /4 phase difference. The incident circularly polarized light 41, 41' of the display passes through the bottom surface of the display 10 and is incident on the sensor 100 at the lower part of the display.

The incident display circularly polarized light 41, 41' passes through the sensor retardation layer 120 and becomes the incident sensor linearly polarized light 42, 42'. As described above, since the slow axis of the display retardation layer 12 and the slow axis of the sensor retardation layer 120 extend substantially parallel, the first and second polarized portions of the circularly polarized light 41, 41' incident on the display are increased by λ/4. Therefore, the mutual phase difference becomes λ/2. Thereby, the polarization axis of the linear polarized light 42 and 42' incident on the sensor is rotated by about 90 degrees from the second angle and is inclined at a first angle, for example +45 degrees, with respect to the slow axis of the sensor retardation layer 120.

The incident sensor linearly polarized light 42 passes through the first sensor polarizing layer 110 and travels to the first light receiving section 320 substantially without loss. On the contrary, most of the incident sensor linearly polarized light 42' is blocked by the second sensor polarizing layer 115 and only a part of it goes to the first sensor. The second light receiving part 330 moves forward. The first sensor polarization layer 110 may have a polarization axis inclined at a first angle, for example +45 degrees, with respect to the slow axis of the sensor delay layer 120. Therefore, the incident sensor linear polarization 42 having the polarization axis inclined at the same angle as the polarization axis of the first sensor polarization layer 110 can pass through the first sensor polarization layer 110. Conversely, the second sensor polarizing layer 115 may have a polarizing axis inclined at a second angle, for example, -45 degrees with respect to the sensor retardation layer 120. Therefore, most of the incident sensor linearly polarized light 42' having a polarization axis rotated 90 degrees with respect to the polarization axis of the second sensor polarization layer 115 is blocked by the second sensor polarization layer 115, and only a part can pass through the second sensor polarization layer 115 .

The incident sensor linearly polarized light 42 after passing through the first sensor polarization layer 110 becomes the first sensor incident light 43, and the incident sensor linearly polarized light 42' after passing through the second sensor polarization layer 115 becomes the second sensor incident light 43'. The incident light 43 of the first sensor is the linearly polarized light of the reflective sensor (32 in FIG. 1) and the linearly polarized light 18 of the sensor generated by the first external light. The second sensor incident light 43' is the sensor linearly polarized light 19 generated by the second external light.

The photosensor 300 includes a first light receiving unit 320 corresponding to the first light path and a second light receiving unit 330 corresponding to the second light path. For example, the first light receiving section 320 generates a first pixel current that is substantially proportional to the brightness of the incident light 43 from the first sensor, that is, the amount of light, and the second light receiving section 330 generates a first pixel current that is substantially proportional to the brightness of the incident light 43' from the second sensor. The second pixel current. The first light receiving unit 320 or the second light receiving unit 330 is composed of, for example, one photodiode or a plurality of photodiodes (hereinafter referred to as a PD array). Here, the first light receiving unit 320 and the second light receiving unit 330 can together detect light belonging to a specific wavelength range, such as near infrared rays, infrared rays, and the like.

FIG. 4 is a diagram for schematically explaining when light irradiated from a sensor at the lower part of the display shown in FIG. 3 is reflected inside the display. Here, it is assumed that there is no induced light reflected back by external objects.

The internally reflected induced light causes serious errors in the brightness of the light measured by the first light receiving section 320 and the second light receiving section 330. The induced light reflected internally is different from the induced light reflected outside the display in many aspects, such as the brightness (or intensity) of the light, the time to reach the light receiving part, and the like. When using the sensor at the bottom of the display as a proximity sensor, you need to consider the influence of internal reflections.

The induced light 20, 20' generated by the light irradiating portion 310 of the sensor 100 at the lower part of the display becomes the induced sensor circularly polarized light 22, 22' as it passes through the first sensor polarizing layer 110 and the sensor retardation layer 120. The inductive sensor circularly polarized light 22, 22' can be reflected inside the display 10 and be incident on the sensor 100 in the lower part of the display again. In the display 10, various structures formed of materials that transmit or reflect light are mixed. Thus, a part of the circularly polarized light 22, 22' of the induction sensor can be returned to the sensor 100 at the lower part of the display by internal reflection. The induced light 20 is the light irradiated to the first light receiving section 320 at an angle incident on the first light receiving section 320 through internal reflection, and the induced light 20' is incident to the second light receiving section 330 at an angle through internal reflection and incident on the second light receiving section 330. The light irradiated by the light receiving unit 330.

The internally reflected sensor circularly polarized light 50 passes through the sensor delay layer 120 to become the internally reflected sensor linearly polarized light 51. The polarization axis of the linear polarization 51 of the internal reflection sensor is rotated by about 90 degrees from the polarization axis of the linear polarization 21 of the sensor sensor. Thus, the polarization axis of the internal reflection sensor linear polarization 51 is substantially perpendicular to the polarization axis of the first sensor polarization layer 110, so that most of the internal reflection sensor linear polarization 51 can be substantially blocked by the first sensor polarization layer 110. The linearly polarized light 52 of the internal reflection sensor passing through without being blocked can be detected by the first light receiving unit 320.

Conversely, the internally reflected sensor circularly polarized light 50' passes through the sensor delay layer 120 to become the internally reflected sensor linearly polarized light 51'. The polarization axis of the linear polarization 51' of the internal reflection sensor is rotated about 90 degrees from the polarization axis of the linear polarization 21 of the sensor sensor. Thus, the polarization axis of the internal reflection sensor linear polarization 51' is substantially parallel to the polarization axis of the second sensor polarization layer 115, so that it can pass through the second sensor polarization layer 115.

Due to the linearly polarized light 52 of the internal reflection sensor passing through without being blocked, a proportional relationship K ₂ : 1 (where K ₂ <1) is established between the brightnesses respectively detected by the first light receiving section 320 and the second light receiving section 330. Here, K ₂ is the blocking transmission ratio of internal reflection.

FIG. 5 is a diagram for schematically explaining another embodiment of the sensor in the lower part of the display. Since the process until the induced light 20 reaches the external object is similar to that of FIG. 1, the process of returning the reflected light to the sensor 100 at the lower part of the display will be described. The explanation is given assuming that there is no internal reflection.

The sensor 101 at the lower part of the display includes a first sensor retardation layer 120, a second sensor retardation layer 125, a sensor polarization layer 110, and a photosensor 300. The first sensor retardation layer 120 and the second sensor retardation layer 125 are arranged on the upper part of the sensor polarizing layer 110, and the photosensor 300 is arranged on the lower part of the sensor polarizing layer 110. The photosensor 300 includes a light irradiation unit 310, a first light receiving unit 320, and a second light receiving unit 330. The first light receiving part 320 is arranged at a position where light emitted from the first sensor delay layer 120 passes through the sensor polarizing layer 110 and the second light receiving part 330 is arranged after light emitted from the second sensor delay layer 125 passes through the sensor polarizing layer 110 The location reached. As an example, the sensor 101 at the lower part of the display can be manufactured by laminating the first sensor retardation layer 120 and the second sensor retardation layer 125 on the upper surface of the sensor polarizing layer 110. The laminated sensor polarizing layer 110 and the first sensor retardation layer 120 and the second sensor retardation layer 125 may be attached to the bottom surface of the display 10. The light sensor 300 may be attached to the bottom surface of the sensor polarizing layer 110. As another embodiment, the light sensor 300 may be realized by a thin film transistor. Thus, the sensor 101 in the lower part of the display can be manufactured by laminating the film-like first sensor retardation layer 120, the second sensor retardation layer 125, the sensor polarizing layer 110, and the photosensor 300.

The slow axis of the first sensor delay layer 120 and the slow axis of the second sensor delay layer 125 are substantially orthogonal. The polarization axis of the sensor polarizing layer 110 may be inclined at a first angle, such as +45 degrees, with respect to the slow axis of the first sensor retardation layer 120, or may be inclined at a second angle, such as -45 degrees, with respect to the slow axis of the second sensor retardation layer 125. .

The first light-receiving part 320 of the photosensor 300 is located in the vertical lower part of the first sensor retardation layer 120 and detects the first circularly polarized light 41 emitted by the incident display through the first sensor retardation layer 120 and the sensor polarizing layer 110 (first light path). The sensor incident light 43. The second light receiving part 330 of the photosensor 300 is located at the vertical lower part of the second sensor retardation layer 125 and detects the first circularly polarized light 41' emitted from the incident display through the second sensor retardation layer 125 and the sensor polarizing layer 110 (second light path) The two sensors incident light 43". The first light receiving unit 320 and the second light receiving unit 330 can generate a pixel current having a magnitude corresponding to the brightness of the detected light. The first light receiving unit 320 and the second light receiving unit 330 may be photoelectric, for example. Diode, but not limited to this.

Next, the operation of the sensor 101 at the lower part of the display configured as described above will be described.

The incident display circularly polarized light 41 passes through the first sensor retardation layer 120 to become the first incident sensor linearly polarized light 42, and the incident display circularly polarized light 41' passes through the second sensor retardation layer 125 to become the second incident sensor linearly polarized light 42". As described above, Since the slow axis of the first sensor retardation layer 120 is orthogonal to the slow axis of the second sensor retardation layer 125, the polarization axis of the first incident sensor linear polarization 42 and the polarization axis of the second incident sensor linear polarization 42" can also be orthogonal . In detail, the incident display circularly polarized light 41 having a phase difference of λ/4 between the first polarized part and the second polarized part is increased by a phase difference of λ/4 through the first sensor retardation layer 120, thereby being able to have a phase difference with the sensor. The polarization axis of the polarizing layer 110 is substantially parallel to the first incident sensor linearly polarizing light 42. Conversely, the incident display circularly polarized light 41' passes through the second sensor retardation layer 125 to cancel the phase difference, so that it can become the second incident sensor linearly polarized light 42" having a polarization axis substantially perpendicular to the polarization axis of the sensor polarization layer 110.

The first incident sensor linearly polarized light 42 passes through the sensor polarizing layer 110 and travels to the first light receiving portion 320 substantially without loss. On the contrary, most of the second incident sensor linearly polarized light 42" is blocked by the sensor polarizing layer 110 and only part of it goes to the first light-receiving part 320. The second light receiving portion 330 advances. The sensor polarizing layer 110 may have a polarization axis inclined at a first angle, for example +45 degrees, with respect to the slow axis of the first sensor retardation layer 120 or a second sensor with respect to the slow axis of the second sensor retardation layer 125. The angle of the polarization axis is, for example, -45 degrees. Therefore, the first incident sensor linear polarization 42 having the polarization axis that is inclined at the same angle as the polarization axis of the sensor polarization layer 110 can pass through the sensor polarization layer 110. Conversely, it has the opposite to the polarization axis. Most of the second incident sensor linear polarization 42 ″ with the polarization axis of the sensor polarization layer 110 rotated by 90 degrees is blocked by the sensor polarization layer 110, and only a portion can pass through the sensor polarization layer 110.

The first incident sensor linearly polarized light 42 after passing through the sensor polarization layer 110 becomes the first sensor incident light 43, and the second incident sensor linearly polarized light 42" after passing through the sensor polarization layer 110 becomes the second sensor incident light 43". The incident light 43 of the first sensor is the linearly polarized light of the reflective sensor (32 in FIG. 1) and the linearly polarized light 18 of the sensor generated by the first external light. The second sensor incident light 43" is the sensor linearly polarized light 19 generated by the second external light.

The photosensor 300 includes a first light receiving unit 320 corresponding to the first light path and a second light receiving unit 330 corresponding to the second light path. For example, the first light receiving section 320 generates a first pixel current that is substantially proportional to the brightness of the incident light 43 from the first sensor, and the second light receiving section 330 generates a second pixel current that is substantially proportional to the brightness of the incident light 43" from the second sensor. Pixel current.

FIG. 6 is a diagram for schematically explaining when light irradiated from a sensor at the lower part of the display shown in FIG. 5 is reflected inside the display. The description overlapping with FIG. 4 will be omitted, and only the differences will be described. Here, it is assumed that there is no induced light reflected back by external objects.

The internally reflected sensor circularly polarized light 50 passes through the first sensor delay layer 120 to become the internally reflected sensor linearly polarized light 51. The polarization axis of the linear polarization 51 of the internal reflection sensor is rotated by about 90 degrees from the polarization axis of the linear polarization 21 of the sensor sensor. Thus, the polarization axis of the internal reflection sensor linear polarization 51 is perpendicular to the polarization axis of the first sensor polarization layer 110, so that most of the internal reflection sensor linear polarization 51 can be substantially blocked by the sensor polarization layer 110. The linearly polarized light 52 of the internal reflection sensor passing through without being blocked can be detected by the first light receiving unit 320.

Conversely, the internally reflected sensor circularly polarized light 50' passes through the second sensor delay layer 125 to become the internally reflective sensor linearly polarized light 51". The polarization axis of the internally reflective sensor linearly polarized light 51" is substantially parallel to the polarization axis of the sensor sensor linearly polarized light 21 . Thus, the polarization axis of the internal reflection sensor linear polarization 51 ″ is substantially parallel to the polarization axis of the second sensor polarization layer 115, so that it can pass through the second sensor polarization layer 115.

In the structure shown in FIG. 3 or FIG. 5, the blocking transmission ratio K _{1 of} external light is measured (S10). Through blocking ratio K ₁ according to the first incident light of linear polarization of the first portion outside light sensor 320 and the brightness of the generated light incident on the second portion 18 in a state 330 in the light irradiation section 310 (turn off) Close Calculate the brightness of the sensor linearly polarized light 19 generated by the second external light. _{A plurality of blocking transmission ratios K 1} can be calculated by adjusting the brightness of the external light 14 or the positions of the

sensors

100 and 101 at the lower part of the display.

Measure the internal reflection blocking transmission ratio K ₂ (S11). The blocking transmission ratio K ₂ can be based on the brightness of the internal reflection sensor linearly polarized light 51 incident on the first light receiving section 320 and the internal reflection sensor linearly polarized light 51' or 51" incident on the second light receiving section 330 without external light. _{It is possible to calculate a plurality of blocking transmittance ratios K 2} by adjusting the brightness of the sensing light 20 or the positions of the

sensors

100 and 101 at the lower part of the display.

Barrier measured external light transmitted through internal reflection ratio K ₁ and K barrier transmission rate by a first sensor ₂ for correcting the

measurement sensors

100, 101 monitor the lower portion of the incident light luminosity 43 (S20). If the sensor at the bottom of the display works as a proximity sensor, not only the incident light 43 from the first sensor and the incident light 43 from the second sensor, but also the internally reflected induced light 51', 51", 52 will also be incident on the first light receiving part 320 And the second light receiving section 330. Not only the internally reflected sensing light 52 incident on the first light receiving section 320, but also the internally reflected sensing light 51', 51' incident on the second light receiving section 330 will also make the light receiving section 320 The measurement value of 330 produces an error.

If the brightness of the incident light 43 from the first sensor is set to A, the brightness of the incident light 43' from the second sensor is K ₁ ×A. On the other hand, if the brightness of the induced light 51', 51" reflected internally is set to B, the brightness of the induced light 52 internally reflected is K ₂ ×B.

The brightness C of the light detected by the first light receiving unit 320 is based on the incident light 43 from the first sensor and the induced light 52 reflected internally.

【Formula 1】

C=A+K ₂ ×B

On the other hand, the brightness D of the light detected by the second light receiving unit is based on the incident light 43' of the second sensor and the induced light 51', 51" reflected internally.

[Formula 2]

D=K ₁ ×A+B

From Formula 1 and Formula 2, the brightness A of the incident light 43 from the first sensor can be calculated in the following manner.

The brightness of the incident light 43 from the first sensor is used to calculate the distance to an external object or determine whether it is close (S21).

The above description of the present invention is exemplary. For those skilled in the art to which the present invention belongs, those skilled in the art can understand that it can be easily transformed into other specific embodiments without changing the technical concept or essential features of the present invention. Way. Therefore, it should be understood that the above-described embodiments are all exemplary and not intended to be limiting. In addition, the features of the present invention described with reference to the drawings are not limited to the structures shown in the specific drawings, and can be realized by alone or in combination with other features.

The scope of the present invention is presented by the appended claims rather than the above description. It should be understood that all changes or modifications can be derived from the meaning and scope of the claims and their equivalent concepts All are included in the scope of the present invention.

Claims

A sensor in the lower part of a display, the sensor in the lower part of the display is arranged on the lower part of a display including a pixel that generates light, a display retardation layer arranged on the upper part of the pixel, and a display polarizing layer, and is characterized in that:

The sensors at the lower part of the display include:

The light sensor includes a light irradiating part, a first light receiving part, and a second light receiving part, the light irradiating part irradiates sensing light for sensing an object located outside the display, the first light receiving part and the second light receiving part Detecting the external reflection light of the induction light reflected from the object and the internal reflection light of the induction light reflected inside the display;

The first sensor polarizing layer is disposed on the upper part of the first light receiving part and has a polarizing axis inclined at a first angle;

The second sensor polarizing layer is disposed on the upper part of the second light receiving part and has a polarizing axis inclined at a second angle; and

The sensor retardation layer is arranged on the upper part of the sensor polarization layer and has a slow axis inclined at a first angle with respect to the polarization axis,

The first sensor polarization layer and the sensor delay layer allow the external reflected light to pass through, and allow the internally reflected light to pass through at a blocking transmission ratio of the internal reflection,

The second sensor polarizing layer and the sensor retardation layer pass the blocking transmission ratio of the external reflected light and the internal reflected light.
The sensor at the lower part of the display according to claim 1, characterized in that:

The brightness of the external reflected light is calculated using the blocking transmission ratio of the external light and the blocking transmission ratio of the internal reflection.
The sensor at the lower part of the display according to claim 1, characterized in that:

The first sensor polarizing layer and the sensor delay layer convert the induced light into the circularly polarized light of the sensor so as to pass through the display polarizing layer,

The circularly polarized light of the inductive sensor is converted into linearly polarized light of the inductive display having the same polarization axis as that of the polarizing layer of the display through the display retardation layer.
The sensor at the lower part of the display according to claim 1, characterized in that:

The slow axis of the sensor retardation layer is parallel to the slow axis of the display retardation layer,

The polarization axis of the display polarizing layer is inclined at a second angle with respect to the slow axis of the display retardation layer.
The sensor at the lower part of the display according to claim 4, characterized in that:

The difference between the second angle and the first angle is 90 degrees.
A sensor in the lower part of a display, the sensor in the lower part of the display is arranged on the lower part of a display including a pixel that generates light, a display retardation layer arranged on the upper part of the pixel, and a display polarizing layer, and its characteristics are:

The sensors at the lower part of the display include:

The light sensor includes a light irradiating part, a first light receiving part, and a second light receiving part, the light irradiating part irradiates sensing light for sensing an object located outside the display, the first light receiving part and the second light receiving part Detecting the external reflection light of the induction light reflected from the object and the internal reflection light of the induction light reflected inside the display;

The sensor polarizing layer is arranged on the upper part of the light sensor and has a polarizing axis inclined at a first angle;

The first sensor retardation layer is disposed on the upper part of the sensor polarization layer corresponding to the first light receiving part, and has a slow axis inclined at a first angle with respect to the polarization axis; and

The second sensor retardation layer is arranged on the upper part of the sensor polarizing layer corresponding to the second light-receiving part, and has a slow axis inclined at a second angle with respect to the polarizing axis, the sensor polarizing layer and the The first sensor retardation layer allows the external reflected light to pass through, and allows the internally reflected light to pass through at the blocking transmission ratio of the internal reflection,

The sensor polarizing layer and the second sensor retardation layer pass the blocking transmission ratio of the external reflected light and the internal reflected light.
The sensor at the bottom of the display according to claim 6, characterized in that:

The brightness of the external reflected light is calculated using the blocking transmission ratio of the external light and the blocking transmission ratio of the internal reflection.
The sensor at the bottom of the display according to claim 6, characterized in that:

The sensor polarizing layer and the first sensor delay layer convert the induced light into the circularly polarized light of the sensor so as to pass through the display polarizing layer,

The circularly polarized light of the inductive sensor is converted into linearly polarized light of the inductive display having the same polarization axis as that of the polarizing layer of the display through the display retardation layer.
The sensor at the bottom of the display according to claim 6, characterized in that:

The slow axis of the retardation layer of the first sensor is parallel to the slow axis of the retardation layer of the display,

The polarization axis of the display polarizing layer is inclined at a second angle with respect to the slow axis of the display retardation layer.
The sensor at the lower part of the display according to claim 1 or 6, characterized in that:

The blocking transmission ratio of the external light is measured in a state where the light irradiating portion is closed, and the blocking transmission ratio of the internal reflection is measured in a state where there is no external reflected light.