CN111670346A

CN111670346A - Illuminance sensor at lower part of display

Info

Publication number: CN111670346A
Application number: CN202080001011.5A
Authority: CN
Inventors: 闵丙日
Original assignee: Hangzhou Xinge Microelectronics Co ltd
Current assignee: Hangzhou Xinge Microelectronics Co ltd
Priority date: 2020-01-21
Filing date: 2020-01-21
Publication date: 2020-09-15
Also published as: WO2021146959A1

Abstract

The present disclosure relates to an illuminance sensor at a lower portion of a display, comprising: a light selection layer having a first light path and a second light path along which display circular polarization generated by external light incident from the outside of the display and non-polarization generated by the pixels proceed; and an optical sensor having a first light receiving part that detects light after passing through the first light path that passes both the display circularly polarized light and the unpolarized light, and a second light receiving part that detects light after passing through the second light path that blocks the display circularly polarized light and passes the unpolarized light.

Description

Illuminance sensor at lower part of display

Technical Field

The present disclosure relates to an illuminance sensor.

Background

The illuminance sensor is used not only in mobile electronic devices such as mobile phones and tablet computers, but also in video electronic devices such as televisions and monitors. The illuminance sensor is a sensor that senses the brightness around the electronic device. Recently, designs in which the display occupies almost the entire front surface of the electronic device have been increased. Although the size of the display becomes large according to the demand for a large screen, it is necessary to secure at least a partial area of the front surface to configure the camera, particularly, the illuminance sensor. Although a proximity sensor using ultrasonic waves or the like can be applied to a structure in which the front surface is covered with a display, it is difficult to integrate a function of sensing illuminance. On the other hand, although the illuminance sensor may be located in a region other than the front surface, it may not sense ambient light due to a housing for protecting the electronic device. Thus, although the most ideal position where the illuminance sensor can be provided is the front surface of the electronic device, in a design in which the display occupies the entire front surface, it is difficult to secure a position where a commonly used illuminance sensor is disposed.

Disclosure of Invention

An object of the present disclosure is to provide an illuminance sensor that can be applied to an electronic device of a design in which a display occupies the entire front surface.

An illuminance sensor under a display according to an embodiment of the present invention is an illuminance sensor under a display that is disposed under a display including a pixel generating light, a display retardation layer disposed above the pixel, and a display polarizing layer, and measures luminance outside the display, the illuminance sensor under the display including: a light selection layer having a first light path and a second light path along which display circular polarization generated by external light incident from the outside of the display and non-polarization generated by the pixels proceed; and an optical sensor having a first light receiving part that detects light after passing through the first light path that passes both the display circularly polarized light and the unpolarized light, and a second light receiving part that detects light after passing through the second light path that blocks the display circularly polarized light and passes the unpolarized light.

Preferably, the light selective layer comprises: a sensor retardation layer for circularly polarized light incident on the display and having orthogonal slow and fast axes; a first sensor polarizing layer located at a lower portion of the sensor retardation layer and having a polarizing axis inclined at a first angle with respect to the slow axis; and a second sensor polarizing layer located at a lower portion of the sensor retardation layer and having a polarizing axis inclined at a second angle with respect to the slow axis, the sensor retardation layer and the first sensor polarizing layer forming the first optical path, the sensor retardation layer and the second sensor polarizing layer forming the second optical path.

Preferably, the plurality of first sensor polarizing layers and the plurality of second sensor polarizing layers are alternately arranged on the same plane.

Preferably, the light selective layer comprises: a first sensor retardation layer for circularly polarized light incident on the display and having orthogonal first slow and fast axes; a second sensor retardation layer for circularly polarized light incident on the display and having orthogonal second slow and fast axes; and a sensor polarizing layer located at a lower portion of the first and second sensor retardation layers and having a polarizing axis inclined at a first angle with respect to the first slow axis, the first slow axis being orthogonal to the second slow axis, the first sensor retardation layer forming the first light path with the sensor polarizing layer, the second sensor retardation layer forming the second light path with the sensor polarizing layer.

Preferably, the plurality of first sensor delay layers and the plurality of second sensor delay layers are alternately arranged on the same plane.

Preferably, the light selective layer comprises: a first sensor retardation layer for circularly polarized light incident on the display and having orthogonal first slow and fast axes; a second sensor retardation layer for circularly polarized light incident on the display and having orthogonal second slow and fast axes; a first sensor polarizing layer located at a lower portion of the first sensor retardation layer and the second sensor retardation layer and having a polarizing axis inclined at a second angle with respect to the first slow axis; and a second sensor polarizing layer located at a lower portion of the first sensor retardation layer and the second sensor retardation layer and having a polarizing axis inclined at a first angle with respect to the first slow axis, the first slow axis being orthogonal to the second slow axis.

Preferably, a plurality of the first sensor retardation layers and a plurality of the second sensor retardation layers are alternately arranged on a first plane, and a plurality of the first sensor polarizing layers and a plurality of the second sensor polarizing layers are alternately arranged on a second plane.

Preferably, the first light receiving unit detects a first sensor linear polarization generated from the display circular polarization and a second sensor linear polarization generated from the unpolarized light, and the second light receiving unit detects a third sensor linear polarization generated from the unpolarized light.

Preferably, the light selective layer comprises: a sensor retardation layer for circularly polarized light incident on the display and having orthogonal slow and fast axes; and a sensor polarizing layer positioned below the sensor retardation layer and having a polarizing axis inclined at a second angle with respect to the slow axis, wherein the sensor retardation layer and the sensor polarizing layer are disposed only above the second photoreceivers.

Preferably, the illuminance sensor at the lower portion of the display further includes: and a condensing lens formed on an upper surface of the light selection layer.

Preferably, the correction is performed by applying a proportional relationship to the luminance of the external light after passing through the first light path, the proportional relationship being established between the luminances of the unpolarized light after passing through the first light path and the second light path, respectively, in an environment not affected by the external light.

The illuminance sensor according to the embodiment of the present disclosure can be applied to an electronic device of such a design that the display occupies the entirety of the front surface.

Drawings

The present disclosure will be described below with reference to embodiments shown in the drawings. For the sake of understanding, the same constituent elements are denoted by the same reference numerals throughout the drawings. The structures shown in the drawings are illustrative of the embodiments of the disclosure only and do not limit the scope of the disclosure. In particular, some components are shown in the drawings with some exaggeration to facilitate understanding of the invention. Since the drawings are for the purpose of understanding the present invention, it is to be understood that widths, thicknesses, and the like of components shown in the drawings may vary in actual implementation.

Fig. 1 is a diagram for schematically illustrating an operation principle of an illuminance sensor at a lower portion of a display;

FIG. 2 is a diagram schematically illustrating one embodiment of the light selective layer shown in FIG. 1;

FIG. 3 is a diagram schematically illustrating another embodiment of the light selection layer shown in FIG. 1;

FIG. 4 is a diagram schematically illustrating yet another embodiment of the light selection layer shown in FIG. 1;

FIG. 5 is a diagram schematically illustrating yet another embodiment of the light selecting layer shown in FIG. 1;

FIG. 6 is an exploded perspective view schematically illustrating one embodiment of an illumination sensor under a display;

fig. 7 is an exploded perspective view for schematically illustrating another embodiment of an illuminance sensor at a lower portion of a display;

fig. 8 is an exploded perspective view for schematically illustrating still another embodiment of an illuminance sensor at a lower portion of a display;

FIG. 9 is a diagram for schematically illustrating the effects produced by light generated in a display;

FIG. 10 is a diagram schematically illustrating one embodiment of an illumination sensor at the lower portion of a display capable of reducing the effects of light generated in the display;

fig. 11 is a diagram for schematically illustrating another embodiment of an illuminance sensor at a lower portion of a display capable of reducing an influence caused by light generated in the display;

fig. 12 is a diagram for schematically illustrating another operation principle of the illuminance sensor at the lower portion of the display;

fig. 13 is an exploded perspective view schematically illustrating an illuminance sensor at the lower portion of the display that operates according to the operation principle shown in fig. 12.

Detailed Description

The present disclosure is capable of various modifications and embodiments, and specific embodiments thereof are shown in the drawings and will be described herein in detail. It should be understood that it is not intended to limit the present disclosure to the particular embodiments, but rather, to include all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure. In particular, functions, features, embodiments to be described below with reference to the drawings can be implemented alone or in combination with another embodiment. Accordingly, it should be noted that the scope of the present disclosure is not limited by the manner shown in the accompanying drawings.

On the other hand, with respect to terms used in this specification, expressions such as "substantially", "almost", "about" and the like are expressions considering a difference (margin) allowed at the time of actual implementation or an error that may occur. For example, for "substantially 90 degrees", it should be construed that an angle capable of obtaining the same effect as that at 90 degrees is also included. As another example, "substantially free" should be construed to include to the extent that it can be ignored, if at all.

On the other hand, in the case where no particular mention is made, "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, the angle, the incident angle, and the like are based on a virtual straight line perpendicular to a horizontal plane shown in the drawing, unless otherwise specified.

Throughout the drawings, the same or similar elements are referred to using the same reference numerals.

Fig. 1 is a diagram schematically illustrating an operation principle of an illuminance sensor at a lower portion of a display.

The illuminance sensor 100 under the display is disposed under the display 10. The display 10 includes a pixel layer 13 formed with a plurality of pixels P generating light, a display polarizing layer 11 laminated on an upper portion of the pixel layer 13, and a display retardation layer 12. 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 illuminance sensor 100 under the display constituted by the light selective layer 200 and the light sensor 300 may be disposed in a region where a part of the protective layer is removed (hereinafter, referred to as a complete structure). As another example, the light selection layer 200 of the illuminance sensor 100 at the lower portion of the display may be manufactured in a film shape and laminated on the bottom surface of the display 10. The illuminance sensor at the lower portion of the display may be implemented in such a manner that the light sensor 300 is attached to the bottom surface of the light selection layer 200 (hereinafter, referred to as an assembly type structure). In the following, the description will be focused on the completed structure in order to avoid redundant description.

The display polarizing layer 11 and the display retardation layer 12 can improve the visibility of the display 10. The external light 20 incident through the upper surface of the display 10 is unpolarized light. When the external light 20 is incident on the upper surface of the display polarizing layer 11, only the display linear polarization 21 substantially aligned with the polarization axis of the display polarizing layer 11 passes through the display polarizing layer 11. When the display linear polarization 21 passes through the display retardation layer 12, the display circular polarization 22 (or elliptical polarization) rotates in the clockwise direction or the counterclockwise direction. When the display circular polarization 22 is reflected by the pixel layer 13 and enters the display retardation layer 12 again, it becomes the second linear polarization. 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 display linear polarization 21 and the polarization axis of the second linear polarization are orthogonal to each other. Thus, the second linearly polarized light, i.e., the external light reflected by the pixel layer 13 is blocked by the display polarizing layer 11 and cannot be emitted to the outside of the display. This can improve the visibility of the display 10.

The unpolarized light 30 generated by the pixel P travels not only toward the upper surface of the display 10, but also toward the bottom surface. In addition, a portion of the unpolarized light 30 that travels toward the upper surface is reflected inside the display 10 and travels toward the bottom surface again. Unlike the display circular polarization 22, the unpolarized light 30 passes directly through the display retardation layer 12, is linearly polarized by the display polarization layer 11, and is emitted to the outside.

The illuminance sensor 100 at the lower portion of the display includes a light selection layer 200 having 2 light paths and a light sensor 300 detecting light after passing through each light path. Light incident on the illuminance sensor 100 at the lower portion of the display is display circular polarized light 22 generated from outside light 20 and unpolarized light 30 generated inside the display. The first and second light paths within the light selection layer 200 function in different ways for the display circularly polarized light 22 and the unpolarized light 30. The first light path passes both the display circularly polarized light 22 and the unpolarized light 30. Instead, the second optical path passes the unpolarized light 30 and substantially blocks the display circularly polarized light 22. The display circular polarized light 22 after passing through the first light path becomes the first sensor linear polarized light 23, and the unpolarized light 30 after passing through the first and second light paths becomes the second and third sensor linear

polarized lights

31 and 32.

The optical sensor 300 includes a first light receiving part 310 corresponding to a first optical path and a second light receiving part 320 corresponding to a second optical path. For example, the first light receiving part 310 generates a first pixel current substantially proportional to the light quantities of the display circular polarized light 22 and the unpolarized light 30, and the second light receiving part 320 generates a second pixel current substantially proportional to the light quantities of the unpolarized light 30. The

light receiving unit

310 or 320 may be formed of, for example, 1 photodiode or a plurality of photodiodes (hereinafter, referred to as a PD array). As an embodiment, 1 or 2 photodiodes may correspond to 1 pixel P. As another example, the PD array may correspond to 1 pixel P. As still another embodiment, 1 or 2 photodiodes may correspond to a plurality of pixels P. As yet another example, the PD array may correspond to a plurality of pixels P. Here, the first light receiving part 310 and the second light receiving part 320 may detect light belonging to a specific wavelength range together, or may detect light belonging to different wavelength ranges, for example, red, green, cyan, and near infrared rays.

The illuminance sensor is a device for measuring the brightness of outside light. When the illuminance sensor is disposed below the display, not only the external light that has passed through the display but also the light generated inside the display enters the illuminance sensor. Therefore, in order to accurately measure the luminance of the outside light, it is necessary to measure the luminance of light generated inside the display. If only the brightness of light generated inside the display can be measured, the brightness of external light measured by this can be corrected.

As described above, the second sensor linear polarization 31 and the third sensor linear polarization 32 generated from the unpolarized light 30 can be detected by the first light receiving part 310 and the second light receiving part 320, respectively. In particular, since the light selection layer 200 does not substantially allow the linearly polarized light generated from the display circularly polarized light 22 to enter the second photoreceivers 320, the second photoreceivers 320 can measure only the luminance of the third sensor linearly polarized light 32 generated from the unpolarized light 30. On the other hand, the brightness of the second sensor linear polarization 31 and the third sensor linear polarization 32 may be substantially the same, or may be different, and will be described in detail below. However, since the second sensor linear polarization 31 and the third sensor linear polarization 32 are generated from the unpolarized light 30 generated from 1 or more pixels, a linear proportional relationship or a non-linear proportional relationship is established for the luminance between the two. The nonlinear proportional relationship may be caused by various factors such as structural characteristics of the display 10, differences in pixel regions corresponding to the respective light receiving portions, and the wavelength range of the unpolarized light 30. The proportional relationship between the second sensor linear polarization 31 and the third sensor linear polarization 32 can be measured in an environment free from the influence of the external light 20. From the proportional relationship, the degree to which the second sensor linear polarization 31 contributes to the luminance measured by the first light receiving unit 310 can be calculated from the luminance of the third sensor linear polarization 32 measured by the second light receiving unit 320. This enables the brightness of the outside light 20 to be measured accurately.

In the following, in all the figures, 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 polarizing axis with respect to the slow axis extending in the horizontal direction. 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 shown to aid understanding, it being understood that the slow axis of the sensor retarder need not be aligned with the slow axis of the display retarder. On the other hand, in order to simplify the drawing, only light emitted through the light selection layer is shown for unpolarized light emitted from the pixel P.

Fig. 2 is a diagram schematically illustrating an embodiment of the light selection layer shown in fig. 1.

The light selection layer 200 includes a sensor retardation layer 210, a first sensor polarizing layer 220, and a second sensor polarizing layer 225. The sensor retardation layer 210 is disposed above the first sensor polarizing layer 220 and the second sensor polarizing layer 225, and the optical sensor 300 is disposed below the first sensor polarizing layer 220 and the second sensor polarizing layer 225. The first photoreceivers 310 of the photosensor 300 is disposed below the first sensor polarizing layer 220, and the second photoreceivers 320 is disposed below the second sensor polarizing layer 225. As an example, the light selective layer 200 can be manufactured in a manner that the sensor retardation layer 210 is laminated (laminated) on the upper surfaces of the first sensor polarizing layer 220 and the second sensor polarizing layer 225. The light selective layer 200 may be attached to the bottom surface of the display 10. The light sensor 300 may be attached to the bottom surface of the light selective layer 200. As another embodiment, the light sensor 300 may be implemented by a thin film transistor. Accordingly, the illuminance sensor 100 under the display can be manufactured by laminating the film-shaped sensor retardation layer 210, the first and second

sensor polarizing layers

220 and 225, and the optical sensor 300.

The polarizing axis of the first sensor polarizing layer 220 and the polarizing axis of the second sensor polarizing layer 225 are inclined at different angles with respect to the slow axis of the sensor retardation layer 210. The polarizing axis of the first sensor polarizing layer 220 may be inclined at a first angle, e.g., +45 degrees, with respect to the slow axis of the sensor retardation layer 210, and the polarizing axis of the second sensor polarizing layer 225 may be inclined at a second angle, e.g., -45 degrees, with respect to the slow axis of the sensor retardation layer 210.

The first photoreceivers 310 of the photosensor 300 detects the first sensor linear polarization 23 and the second sensor linear polarization 31 exiting the first sensor polarizing layer 220, and the second photoreceivers 320 detects the third sensor linear polarization 32 exiting the second sensor polarizing layer 225. The

light receiving units

310 and 320 can generate pixel currents having magnitudes corresponding to the amounts of detected light. The

light receiving portions

310 and 320 are, for example, photodiodes, but are not limited thereto.

Next, the operation of the illuminance sensor 100 under the display having the light selection layer 200 having the above-described structure will be described.

The display circular polarization 22 and the unpolarized light (not shown in fig. 2, 30 in fig. 1) are incident on the upper surface of the light selective layer 200, i.e. the upper surface of the sensor retardation layer 210. The display circular polarization 22 is light in which the external light 20 passes through the display polarizing layer 11 and the display retardation layer 12, and the unpolarized light 30 advances downward from the pixel P toward the light selection layer 200.

The display polarizing layer 11 may have a polarizing axis that is inclined at a second angle, e.g. -45 degrees, with respect to the slow axis of the display retarder layer 12. Thus, the display linear polarization 21 after passing through the display polarizing layer 11 may be incident at a second angle with respect to the slow axis of the display retardation layer 12. If the first polarized light portion of the display linear polarization 21 transmitted along the fast axis and the second polarized light portion of the display linear polarization 21 transmitted along the slow axis pass through the display retardation layer 12, a phase difference of λ/4 is generated therebetween. Thus, the display linear polarization 21 after passing through the display retardation layer 12 can be the display circular polarization 22 rotated in the counterclockwise direction.

The display circular polarization 22 having a phase difference of λ/4 between the fast axis and the slow axis becomes the sensor internal linear polarization 22a through the sensor retardation layer 210. The polarization axis of the sensor internal linear polarization 22a and the polarization axis of the display linear polarization 21 are orthogonal to each other. On the other hand, the unpolarized light 30 passes directly through the sensor retardation layer 210.

Since the polarization axis of the first sensor polarizing layer 220 is substantially parallel to the polarization axis of the sensor internal linear polarization 22a, the sensor internal linear polarization 22a exiting the sensor retardation layer 210 can pass through the first sensor polarizing layer 220. In contrast, since the polarization axis of the second sensor polarizing layer 225 is substantially perpendicular to the polarization axis of the sensor internal linear polarization 22a, the sensor internal linear polarization 22a can be blocked by the second sensor polarizing layer 225. On the other hand, the unpolarized light 30 emitted from the sensor retardation layer 210 passes through the first sensor polarizing layer 220 and the second sensor polarizing layer 225, respectively, to become second sensor linear polarized light 31 and third sensor linear polarized light 32. That is, the first photoreceivers 310 can detect the first sensor linearly polarized light 23 and the second sensor linearly polarized light 31 through the first optical path formed by the sensor retardation layer 210-the first sensor polarizing layer 220, and the second photoreceivers 320 can detect the third sensor linearly polarized light 32 through the second optical path formed by the sensor retardation layer 210-the second sensor polarizing layer 225.

Fig. 3 is a diagram schematically illustrating another embodiment of the light selection layer shown in fig. 1.

Light selective layer 201 includes a first sensor retardation layer 230, a second sensor retardation layer 235, and a sensor polarizing layer 240. The first sensor retardation layer 230 and the second sensor retardation layer 235 are disposed on the upper portion of the sensor polarizing layer 240, and the optical sensor 300 is disposed on the lower portion of the sensor polarizing layer 240. The first photoreceivers 310 of the photosensor 300 is disposed at a position where light emitted from the first sensor retardation layer 230 reaches after passing through the sensor polarizing layer 240, and the second photoreceivers 320 is disposed at a position where light emitted from the second sensor retardation layer 235 reaches after passing through the sensor polarizing layer 240. As an example, the light selective layer 201 may be manufactured in a manner of laminating the first sensor retardation layer 230 and the second sensor retardation layer 235 on the upper surface of the sensor polarizing layer 240. The light selective layer 201 may be attached to the bottom surface of the display 10. The light sensor 300 may be attached to the bottom surface of the light selective layer 201. As another embodiment, the light sensor 300 may be implemented by a thin film transistor. Accordingly, the illuminance sensor 100 under the display can be manufactured by laminating the film-shaped first and second sensor retardation layers 230 and 235, the sensor polarizing layer 240, and the optical sensor 300.

The slow axis of the first sensor delay layer 230 is substantially orthogonal to the slow axis of the second sensor delay layer 235. The polarizing axis of the sensor polarizing layer 240 may be tilted at a first angle, e.g., +45 degrees, with respect to the slow axis of the first sensor retardation layer 230, or may be tilted at a second angle, e.g., -45 degrees, with respect to the slow axis of the second sensor retardation layer 235.

The first photoreceivers 310 of the photosensor 300 is positioned vertically below the first sensor retardation layer 230 and detects the first sensor linear polarization 23 and the second sensor linear polarization 31 that are emitted after the display circular polarization 22 passes through the first sensor retardation layer 230 and the sensor polarizing layer 240. The second photoreceivers 320 of the photosensor 300 is located vertically below the second sensor retardation layer 235 and detects the third sensor linear polarization 32. The

light receiving units

light receiving parts

310 and 320 may be, for example, photodiodes, but are not limited thereto.

Next, the operation of the illuminance sensor 100 under the display having the light selection layer 201 having the above-described structure will be described. The display circularly polarized light 22 and the unpolarized light 30 are explained in the same manner as in fig. 2, and therefore, the explanation thereof is omitted.

The display circularly polarized light 22 and unpolarized light (not shown in fig. 3, 30 in fig. 1) are incident on the upper surface of the light selective layer 201, i.e., the upper surfaces of the first sensor retardation layer 230 and the second sensor retardation layer 235. The display circular polarization 22 having a phase difference of λ/4 between the fast axis and the slow axis becomes the first sensor internal linear polarization 22b through the first sensor retardation layer 230, and becomes the second sensor internal linear polarization 22c through the second sensor retardation layer 235. Since the slow axis of first sensor retardation layer 230 is orthogonal to the slow axis of second sensor retardation layer 235, the polarization axis of first sensor internal linear polarization 22b can also be orthogonal to the polarization axis of second sensor internal linear polarization 22 c. Specifically, the display circular polarization 22 having the phase difference of λ/4 between the first polarization part and the second polarization part can be the first sensor internal linear polarization 22b having the polarization axis substantially parallel to the polarization axis of the display linear polarization 21 by eliminating the phase difference by the first sensor retardation layer 230. In contrast, the display circular polarization 22 can become the second sensor internal linear polarization 22c having the polarization axis perpendicular to the polarization axis of the display linear polarization 21 by increasing the phase difference of λ/4 by the second sensor retardation layer 235. On the other hand, the unpolarized light 30 passes directly through the first and second sensor retardation layers 230, 235.

Although the first sensor internal linear polarization 22b exiting the first sensor retardation layer 230 passes through the sensor polarizing layer 240, the second sensor internal linear polarization 22c exiting the second sensor retardation layer 235 cannot pass through the sensor polarizing layer 240. The sensor polarizing layer 240 has a polarizing axis inclined at a first angle, e.g., -45 degrees, with respect to the slow axis of the first sensor retardation layer 230, or has a polarizing axis inclined at a second angle, e.g., +45 degrees, with respect to the slow axis of the second sensor retardation layer 235. Accordingly, the polarization axis of the first sensor internal linear polarization 22b is substantially parallel to the polarization axis of the sensor polarizing layer 240, and thus the first sensor internal linear polarization 22b can pass through the sensor polarizing layer 240 almost without loss. In contrast, the polarization axis of the second sensor internal linear polarization 22c is substantially perpendicular to the polarization axis of the sensor polarizing layer 240, and thus the second sensor internal linear polarization 22c can be blocked by the sensor polarizing layer 240. The unpolarized light 30 having passed through the first sensor retardation layer 230 and the second sensor retardation layer 235 passes through the sensor polarizing layer 240 to become second sensor linear polarized light 31 and third sensor linear polarized light 32. That is, the first photoreceivers 310 can detect the first sensor linear polarization 23 and the second sensor linear polarization 31 through the first optical path constituted by the first sensor retardation layer 230 — the sensor polarizing layer 240. In addition, the second photoreceivers 320 can detect the third sensor linear polarization 32 through the second optical path formed by the second sensor retardation layer 235-the sensor polarizing layer 240.

Fig. 4 is a diagram schematically illustrating yet another embodiment of the light selection layer shown in fig. 1. In fig. 4, the structure of the light selection layer 200 is the same as in fig. 2, the polarization axis of the display polarizing layer 11 'of the display 10' being different from the polarization axis of the display polarizing layer 11 of fig. 2. The operation of the illuminance sensor 100 under the display will be described without overlapping with the description of fig. 2.

The display polarizing layer 11' may have a polarizing axis inclined at a first angle, e.g. +45 degrees, with respect to the slow axis of the display retardation layer 12. Thus, the display linear polarization 21 after passing through the display polarizing layer 11' may be incident at a first angle with respect to the slow axis of the display retardation layer 12. If the first polarization part of the display linear polarization 21 transmitted along the fast axis and the second polarization part of the display linear polarization 21 transmitted along the slow axis pass through the display retardation layer 12, a phase difference of λ/4 is generated therebetween. Thus, the display linear polarization 21 after passing through the display retardation layer 12 can be the display circular polarization 22' rotating in the clockwise direction.

The display circular polarization 22' having a phase difference of λ/4 between the fast axis and the slow axis becomes the sensor internal linear polarization 22d through the sensor retardation layer 210. The polarization axis of the sensor internal linear polarization 22d and the polarization axis of the display linear polarization 21 are orthogonal to each other. On the other hand, the unpolarized light 30 passes directly through the sensor retardation layer 210.

The polarizing axis of the first sensor polarizing layer 220 is perpendicular to the polarizing axis of the sensor internal linear polarization 22d, so the sensor internal linear polarization 22d exiting the sensor retardation layer 210 can be blocked by the first sensor polarizing layer 220. In contrast, the polarization axis of the second sensor polarizing layer 225 is substantially parallel to the polarization axis of the sensor internal linear polarization 22d, so the sensor internal linear polarization 22d can pass through the second sensor polarizing layer 225. On the other hand, the unpolarized light 30 emitted from the sensor retardation layer 210 passes through the first sensor polarizing layer 220 and the second sensor polarizing layer 225, respectively, to become second sensor linear polarized light 31 and third sensor linear polarized light 32. That is, the first light receiving part 320 'can detect the first sensor linearly polarized light 23' and the third sensor linearly polarized light 32 through the first light path constituted by the sensor retardation layer 210-the second sensor polarizing layer 225. On the other hand, the second photoreceivers 310' can detect the second sensor linear polarization 31 through the second optical path constituted by the sensor retardation layer 210 — the first sensor polarizing layer 220.

Fig. 5 is a diagram schematically illustrating yet another embodiment of the light selection layer shown in fig. 1. In fig. 5, the structure of the light selective layer 201 is the same as in fig. 3, the polarization axis of the display polarizing layer 11 'of the display 10' being different from the polarization axis of the display polarizing layer 11 of fig. 3. The operation of the illuminance sensor 100 under the display will be described without overlapping with the description of fig. 3.

The display circular polarization 22' and the unpolarized light (not shown in fig. 5, 30 in fig. 1) rotating in the clockwise direction are incident on the upper surface of the light selection layer 201 (i.e., the upper surfaces of the first sensor retardation layer 230 and the second sensor retardation layer 235). The display circular polarization 22' having a phase difference of λ/4 between the fast axis and the slow axis becomes the first sensor internal linear polarization 22e through the first sensor retardation layer 230, and becomes the second sensor internal linear polarization 22f through the second sensor retardation layer 235. The slow axis of first sensor retarder 230 is orthogonal to the slow axis of second sensor retarder 235, and thus the polarization axis of first sensor internal linear polarization 22e can also be orthogonal to the polarization axis of second sensor internal linear polarization 22 f. Specifically, the display circular polarization 22' having the phase difference of λ/4 between the first polarization part and the second polarization part can be the first sensor internal linear polarization 22e having the polarization axis perpendicular to the polarization axis of the display linear polarization 21 by increasing the phase difference of λ/4 by the first sensor retardation layer 230. On the other hand, the display circular polarization 22' can be converted into the second sensor internal linear polarization 22f having a polarization axis substantially parallel to the polarization axis of the display linear polarization 21 by eliminating the phase difference of λ/4 by the second sensor retardation layer 235. On the other hand, unpolarized light passes directly through the first sensor retardation layer 230 and the second sensor retardation layer 235.

While the first sensor internal linear polarization 22e exiting the first sensor retardation layer 230 cannot pass through the sensor polarizing layer, the second sensor internal linear polarization 22f exiting the second sensor retardation layer 235 can pass through the sensor polarizing layer 240. The sensor polarizing layer 240 has a polarizing axis that is inclined at a first angle, e.g., +45 degrees, with respect to the slow axis of the first sensor retardation layer 230, or has a polarizing axis that is inclined at a second angle, e.g., -45 degrees, with respect to the slow axis of the second sensor retardation layer 235. Accordingly, the polarization axis of the first sensor internal linear polarization 22e is substantially perpendicular to the polarization axis of the sensor polarizing layer 240, and thus the first sensor internal linear polarization 22e can be blocked by the sensor polarizing layer 240. In contrast, the polarization axis of the second sensor internal linear polarization 22f is substantially parallel to the polarization axis of the sensor polarizing layer 240, and thus the second sensor internal linear polarization 22f can pass through the sensor polarizing layer 240 almost without loss. On the other hand, the unpolarized light 30 having passed through the first sensor retardation layer 230 and the second sensor retardation layer 235 passes through the sensor polarizing layer 240 to become second sensor linear polarized light 31 and third sensor linear polarized light 32. That is, the first photoreceivers 320 'can detect the first sensor linear polarization 23' and the third sensor linear polarization 32 through the first optical path constituted by the second sensor retardation layer 235-the sensor polarizing layer 240. On the other hand, the second photoreceivers 310' can detect the second sensor linear polarization 31 through the second optical path constituted by the first sensor retardation layer 230 — the sensor polarizing layer 240.

Fig. 6 is an exploded perspective view schematically illustrating an embodiment of an illuminance sensor at a lower portion of a display.

As described above, the illuminance sensor 10 under the display may be manufactured by laminating the film-shaped sensor retardation layer 202, the sensor polarization layer 203, and the optical sensor 300. The sensor retardation layer 202 may be formed substantially parallel to the slow axis over the entire surface.

The sensor polarizing layer 203 may be formed by alternately arranging the first sensor polarizing layer 220 and the second sensor polarizing layer 225 having different polarizing axes. The first and second

sensor polarizing layers

220 and 225 may have a rectangular shape extending to a direction. Wherein the polarizing axis of the first sensor polarizing layer 220 may be inclined at a first angle with respect to the slow axis of the sensor retardation layer 202, and the polarizing axis of the second sensor polarizing layer 225 may be inclined at a second angle with respect to the slow axis of the sensor retardation layer 202.

The optical sensor 300 includes a plurality of light receiving

portions

310 and 320. The plurality of light receiving

portions

310 and 320 output pixel currents corresponding to the amount of incident light. The first light receiving parts 310 are substantially the same light receiving parts as the second light receiving parts 320, and the first light receiving parts 310 located at positions where light having a relatively large light amount is incident are denoted by "B", and the second light receiving parts 320 located at positions where light having a relatively small light amount is incident are denoted by "D".

Since the first sensor polarizing layer 220 passes the first sensor linear polarization and the second sensor linear polarization (i.e., the first optical path), the first light receiving part 310 is disposed at a lower portion of the first sensor polarizing layer 220 along the length direction of the first sensor polarizing layer 220. In contrast, since the second sensor polarizing layer 225 linearly polarizes only the third sensor (i.e., the second optical path), the second photoreceivers 320 are disposed below the second sensor polarizing layer 225 along the longitudinal direction of the second sensor polarizing layer 220.

Fig. 7 is an exploded perspective view for schematically illustrating another embodiment of an illuminance sensor at a lower portion of a display.

The sensor polarizing layer 203 may be formed by alternately arranging the first sensor polarizing layer 220 and the second sensor polarizing layer 225 having different polarizing axes. The first sensor polarizing layer 220 and the second sensor polarizing layer 225 may have a rectangular shape. Thus, the sensor polarizing layer 203 may have the following structure: each side of the first sensor polarizing layer 220 is in contact with 4 second sensor polarizing layers 225, or each side of the second sensor polarizing layers 225 is in contact with 4 first sensor polarizing layers 220. Wherein the polarizing axis of the first sensor polarizing layer 220 may be inclined at a first angle with respect to the slow axis of the sensor retardation layer 202, and the polarizing axis of the second sensor polarizing layer 225 may be inclined at a second angle with respect to the slow axis of the sensor retardation layer 202.

Since the first sensor polarizing layer 220 passes the first sensor linearly polarized light and the second sensor linearly polarized light (i.e., the first light path), the first light receiving part 310 is disposed at a lower portion of the first sensor polarizing layer 220. In contrast, since the second sensor polarizing layer 225 passes only the third sensor linearly polarized light (i.e., the second light path), the second photoreceivers 320 are disposed below the second sensor polarizing layer 225. Accordingly, the planar arrangement structure of the first and second

light receiving parts

310 and 320 may be substantially the same as the sensor polarizing layer 203.

Fig. 8 is an exploded perspective view schematically illustrating still another embodiment of an illuminance sensor at a lower portion of a display.

The sensor retardation layer 202 may be formed by alternately arranging first and second sensor retardation layers 230 and 235 having slow axes substantially perpendicular to each other. The first sensor delay layer 230 and the second sensor delay layer 235 have a rectangular shape extending to the first direction.

sensor polarizing layers

220 and 225 may have a rectangular shape extending to a second direction orthogonal to the first direction. Wherein the polarizing axis of the first sensor polarizing layer 220 may be inclined at a second angle with respect to the slow axis of the first sensor retardation layer 230, and the polarizing axis of the second sensor polarizing layer 225 may be inclined at a first angle with respect to the slow axis of the first sensor retardation layer 230.

First sensor retardation layer 230-second sensor polarizing layer 225 and second sensor retardation layer 235-first sensor polarizing layer 220 is a first optical path through which the first sensor linear polarization and the second sensor linear polarization pass. First sensor retardation layer 230-first sensor polarizing layer 220 and second sensor retardation layer 235-second sensor polarizing layer 225 is a second optical path that passes only the third sensor linear polarization. Accordingly, the planar arrangement structure of the first and second

light receiving parts

310 and 320 may have the following structure: each side of the first light receiving part 310 contacts 4 second light receiving parts 320, or each side of the second light receiving part 320 contacts 4 first light receiving parts 310.

Fig. 9 is a diagram for schematically illustrating an influence caused by light generated in the display. The light selective layer (200 or 201) is omitted in fig. 8 for simplicity.

The first light receiving part 310 and the second light receiving part 320 of the light sensor 300 need to detect light passing through the same position or region on the bottom surface of the display 10.

In order to emit light from the same position on the bottom surface of the display 10, a pair of light receiving parts (i.e., the first light receiving part 310 and the second light receiving part 320) may be arranged to correspond to one pixel P on the pixel layer 13 of the display 10. In this structure, the areas of the first and second

light receiving parts

310 and 320 may be considerably small due to the pitch between the pixels P on the pixel layer 13. Therefore, the sensitivity of the first light receiving part 310 and the second light receiving part 320 needs to be relatively high compared to the configuration to be described below. Since the first and second

light receivers

310 and 320 detect light generated by the same pixel PG, the amount of linearly polarized light of the second sensor and the amount of linearly polarized light of the third sensor can be substantially the same in a state where there is no external light. In this configuration, there is a possibility that the light amount of linearly polarized light of the second sensor and the light amount of linearly polarized light of the third sensor may differ due to reflection or the like in the display 10.

The amount of light generated by the pixels PG may vary depending on the image being displayed in the display 10. However, since the first and second

light receiving parts

310 and 320 detect light generated by the same pixel PG, a proportional relationship between the light amount of linearly polarized light of the second sensor and the light amount of linearly polarized light of the third sensor can be easily derived.

Similarly, the pair of light receiving portions may detect light emitted from the same region on the bottom surface of the display 10. In this configuration, the areas of the first light receiving part 310 and the second light receiving part 320 can be relatively larger than those of a configuration in which light emitted from the same pixel is detected. Therefore, the sensitivity of the first light receiving part 310 and the second light receiving part 320 may be relatively low compared to the above-described configuration. As shown in the lower end of fig. 9, the first and

second photoreceivers

310 and 320 can detect light emitted from the pixels PB and PR in common. The first photoreceivers 310 may also detect light emitted from PG1 located on the left side of the pixel PB, and the second photoreceivers may also detect light emitted from PG2 located on the right side of the pixel PR. Light generated by pixels located outside the same area may have an effect on the proportional relationship between the amount of light linearly polarized by the second sensor and the amount of light linearly polarized by the third sensor.

Fig. 10 is a diagram schematically illustrating an embodiment of an illuminance sensor under a display capable of reducing an influence of light generated in the display.

Referring to fig. 10, in the illuminance sensor 100 at the lower portion of the display, the light sensor 300 may include first

light receiving parts

310a, 310b, and 310c and second

light receiving parts

320a, 320b, and 320c that are alternately arranged. The pixels P4, P5, and P6 are common to the first photodetecting portion 310b and the second photodetecting portion 320b, the pixels P2, P3, and P4 are common to the second photodetecting portion 320a and the first photodetecting portion 310b, and the pixels P6, P7, and P8 are common to the second photodetecting portion 320b and the first photodetecting portion 310 c. This makes it possible to calculate the proportional relationship among the 4

light receiving units

320a, 310b, 320b, and 310 c. This can substantially reduce or eliminate the influence of light emitted from pixels located outside the same area.

Fig. 11 is a diagram for schematically illustrating another embodiment of an illuminance sensor under a display capable of reducing an influence by light generated in the display.

Referring to fig. 11, the illuminance sensor 100 at the lower portion of the display may further include a condensing lens 240 at the upper portion of the light selection layer 200. The condenser lens 240 condenses light emitted from the same region on the pixel layer 13 toward the first photoreceivers 310 and the second photoreceivers 320. Thereby, the light emitted from the same region is averaged and reaches the first light receiving unit 310 and the second light receiving unit 320. Thereby, the influence of light generated by the specific pixel can be reduced. In addition, since the area of the same region is relatively increased by the condenser lens 240, the influence of light emitted from pixels located outside the same area can be substantially reduced or eliminated. On the other hand, the light quantity of the light incident on the photosensor 300 increases, and the influence of the sensitivity of the light receiving section can be reduced.

Fig. 12 is a diagram schematically illustrating an operation of the illuminance sensor in the lower portion of the display. The description of the difference from fig. 1 will be mainly described with the omission of redundant description.

The illuminance sensor 101 at the bottom of the display is disposed at the bottom of the display 10. The lower illumination sensor 101 of the display includes a light selection layer 200 having two light paths and a light sensor 300 detecting light after passing through each light path. Light incident on the illuminance sensor 101 at the lower portion of the display is display circular polarized light 22 generated from outside light 20 and unpolarized light 30 generated inside the display.

The first and second optical paths within the light selective layer 200 act differently from each other for the display circular polarized light 22 and the unpolarized light 30. The first light path passes the display circularly polarized light 22 and unpolarized light 30. The display circular polarized light 22 and the unpolarized light 30 having passed through the first optical path reach the first light receiving part 310. Instead, the second optical path passes the unpolarized light 30 and substantially blocks the display circularly polarized light 22, as an example. The unpolarized light 30 having passed through the second optical path reaches the second light receiving unit 320 as the third sensor linearly polarized light 32. As another example, the second optical path passes the unpolarized light 30 and passes a portion 23' of the display circularly polarized light 22. The display circular polarized light 22 generated from the external light 20 may be incident to the illuminance sensor 101 at the lower portion of the display through various paths. For example, the external light 20 itself can enter the inside of the display 10 at various incident angles, or the incident angle to the illuminance sensor 101 at the lower part of the display may be various by reflection in the inside of the display 10. Thereby, a part of the polarized light 23' of the display circular polarized light 22 can be detected by the second light receiving part 320. A part of the polarized light 23' of the display circular polarized light 22 detected by the second light receiving part 320 is proportional to the amount of light of the display circular polarized light 22 detected by the first light receiving part 310, or has a substantially constant amount of light.

In one embodiment, the display circular polarization 22 and the unpolarized light 30 may be detected by the first light receiving part 310, and the third sensor linear polarization 32 may be detected by the second light receiving part 320. In the second photoreceivers 320, the linearly polarized light generated by the display circularly polarized light 22 is not incident due to the light-selecting layer 200, and therefore the second photoreceivers 320 can measure only the brightness of the third sensor linearly polarized light 32 generated from the unpolarized light 30. A first proportional relationship is established between the brightness of the display circular polarization 22 and the brightness of the ambient light 20, and a second proportional relationship is established between the unpolarized light 30 and the third sensor linear polarization 32. Wherein the first proportional relationship and the second proportional relationship may be linear or non-linear ratios, the first proportional relationship may be determined according to a result measured in a state where all pixels of the display 10 are turned off (turn off), and the second proportional relationship may be determined according to a result measured in a state where the pixels of the display 10 are turned on (turn on) in a state where there is no extraneous light 20. The brightness of the external light 20 can be determined by correcting the brightness detected by the first light receiving part 310 by the second proportional relationship and then applying the first proportional relationship to the corrected brightness.

In addition, in another embodiment, the display circular polarization 22 and the non-polarized light 30 may be detected by the first light receiving part 310, and the third sensor linear polarization 32 and a portion 23' of the display circular polarization 22 may be detected by the second light receiving part 320. A first proportional relationship is established between the brightness of the display circular polarization 22, the brightness of the ambient light 20, and the brightness of a portion of the polarized light 23', and a second proportional relationship is established between the unpolarized light 30 and the third sensor linear polarization 32. Here, if the luminance of a part of the polarized light 23 'is negligibly small, the luminance of a part of the polarized light 23' may be excluded in the first proportional relationship. On the other hand, in a case where the luminance of the outside light 20 is substantially constant even though it varies, the luminance of a part of the polarized light 23' may be used to correct the luminance of the third sensor linear polarized light 32.

As described above, the illuminance sensor 10 under the display may be manufactured by laminating the film-shaped sensor retardation layer 210, the sensor polarizing layer 225, and the optical sensor 300.

The sensor retardation layer 210 may be formed substantially parallel to the slow axis over the entire surface. In addition, the first light transmission layer 211 may be formed on the same plane as the sensor retardation layer 210. The first light transmissive layer 211 is stacked on the first light receiving part 310 of the photosensor 300.

The sensor polarizing layer 225 may be formed at a lower portion of the sensor retardation layer 210. The polarizing axis of the sensor polarizing layer 225 may be inclined at a second angle with respect to the slow axis of the sensor retardation layer 210. Further, the second light transmission layer 226 may be formed on the same plane as the sensor polarizing layer 225. The second light transmission layer 226 is stacked on the first light receiving part 310 of the photosensor 300. The first light transmission layer 211 and the second light transmission layer 226 may be formed of materials having the same or similar light transmittance.

The above description of the present disclosure is exemplary, and it will be understood by those having ordinary knowledge in the art to which the present disclosure pertains that the present disclosure can be easily modified into other specific forms without changing the technical idea or essential features of the present disclosure. Accordingly, it is to be understood that the above described embodiments are exemplary and not intended to be limiting. In addition, the features of the present disclosure described with reference to the drawings are not limited to the structures shown in the specific drawings, and may be implemented alone or in combination with other features.

The scope of the present disclosure is shown by the appended claims, rather than by the foregoing description, and it should be understood that all changes and modifications derived from the meaning and scope of the claims and the equivalent concept thereof are included in the scope of the present disclosure.

Claims

1. An illuminance sensor under a display, which is disposed under a display including a pixel generating light, a display retardation layer disposed on an upper portion of the pixel, and a display polarizing layer, and measures brightness of an outside of the display, wherein the illuminance sensor under the display comprises:

a light selection layer having a first light path and a second light path along which display circular polarization generated by external light incident from the outside of the display and non-polarization generated by the pixels proceed; and

an optical sensor having a first light receiving unit for detecting light having passed through the first optical path and a second light receiving unit for detecting light having passed through the second optical path,

the first light path passes both the circularly polarized light and the unpolarized light of the display,

the second light path blocks the display from circularly polarizing and passes the unpolarized light.

2. The lower-display illuminance sensor of claim 1, wherein the light selection layer comprises:

a sensor retardation layer for circularly polarized light incident on the display and having orthogonal slow and fast axes;

a first sensor polarizing layer located at a lower portion of the sensor retardation layer and having a polarizing axis inclined at a first angle with respect to the slow axis; and

a second sensor polarizing layer located at a lower portion of the sensor retardation layer and having a polarizing axis inclined at a second angle with respect to the slow axis,

the sensor retardation layer and the first sensor polarization layer form the first light path,

the sensor retardation layer and the second sensor polarization layer form the second optical path.

3. The lower-display illuminance sensor of claim 2, wherein the first and second sensor polarizing layers are alternately arranged in the same plane.

4. The lower-display illuminance sensor of claim 1, wherein the light selection layer comprises:

a first sensor retardation layer for circularly polarized light incident on the display and having orthogonal first slow and fast axes;

a second sensor retardation layer for circularly polarized light incident on the display and having orthogonal second slow and fast axes; and

a sensor polarizing layer located at a lower portion of the first sensor retardation layer and the second sensor retardation layer and having a polarizing axis inclined at a first angle with respect to the first slow axis,

the first slow axis is orthogonal to the second slow axis,

the first sensor retardation layer forms the first optical path with the sensor polarizing layer,

the second sensor retardation layer forms the second optical path with the sensor polarizing layer.

5. The lower-display illuminance sensor of claim 4, wherein the plurality of first sensor retardation layers and the plurality of second sensor retardation layers are alternately arranged on the same plane.

6. The lower-display illuminance sensor of claim 1, wherein the light selection layer comprises:

a second sensor retardation layer for circularly polarized light incident on the display and having orthogonal second slow and fast axes;

a first sensor polarizing layer located at a lower portion of the first sensor retardation layer and the second sensor retardation layer and having a polarizing axis inclined at a second angle with respect to the first slow axis; and

a second sensor polarizing layer located at a lower portion of the first sensor retardation layer and the second sensor retardation layer and having a polarizing axis inclined at a first angle with respect to the first slow axis,

the first slow axis is orthogonal to the second slow axis.

7. The lower-display illumination sensor of claim 6, wherein the first and second plurality of sensor retardation layers are alternately arranged in a first plane and the first and second plurality of sensor polarizing layers are alternately arranged in a second plane.

8. The illuminance sensor under a display according to claim 2, 4 or 6, wherein the first light-receiving part detects a first sensor linear polarization generated from the display circular polarization and a second sensor linear polarization generated from the unpolarized light, and the second light-receiving part detects a third sensor linear polarization generated from the unpolarized light.

9. The lower-display illuminance sensor of claim 1, wherein the light selection layer comprises:

a sensor retardation layer for circularly polarized light incident on the display and having orthogonal slow and fast axes; and

and a sensor polarizing layer positioned below the sensor retardation layer and having a polarizing axis inclined at a second angle with respect to the slow axis, wherein the sensor retardation layer and the sensor polarizing layer are disposed only above the second photoreceivers.

10. The lower-display illumination sensor of claim 1, wherein the lower-display illumination sensor further comprises: and a condensing lens formed on an upper surface of the light selection layer.

11. The illuminance sensor under display according to claim 1, wherein a proportional relationship is applied to and corrected for the luminance of the external light after passing through the first light path, the proportional relationship being established between the luminances of the unpolarized light after passing through the first and second light paths, respectively, in an environment free from the influence of the external light.