Display substrate and display device thereof

Abstract

The embodiment of the invention provides a display substrate for light sensing and related display equipment. The display substrate comprises a substrate body and pixels arranged on the substrate body in an array mode. The pixel includes a light emitting element and a light blocking element. The light-emitting element is located on the substrate. The light-emitting element includes a first sub-light-emitting element. The first sub-light-emitting element is multiplexed as a photosensitive element and is configured to sense reflected light reflected from an object in contact with or adjacent to the photosensitive element and generate a sensing signal according to the sensed reflected light. The orthographic projection of the light blocking element on the substrate is adjacent to and surrounds the orthographic projection of the photosensitive element on the substrate so as to block light except the reflected light from entering the photosensitive element.

Description

Display substrate and display device thereof TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to the field of display technology, and in particular, to a display substrate and a display device thereof. BACKGROUND

[0002] With the rapid development of display-related technologies, compared with traditional liquid crystal display devices and organic light-emitting diode display devices, Micro LED display devices have higher light-emitting efficiency, longer service life, and higher brightness, and also have the advantages of thinness, power saving, and all-weather use. Therefore, Micro LED display technology has become a research hotspot in the field of display-related technologies.

[0003] Currently, display devices usually have the function of recognizing the motion or texture of a finger (or other operating object) under the screen. For a Micro LED display device, this recognition function can be achieved by multiplexing light-emitting LEDs.

[0004] SUMMARY

[0005] Embodiments of the present disclosure provide a display substrate and a related display device.

[0006] According to a first aspect of the present disclosure, a display substrate for light sensing is provided. The display substrate includes a substrate and an array of pixels disposed on the substrate. The pixel includes a light-emitting element and a light-blocking element. The light-emitting element is located on the substrate. The light-emitting element includes a first sub-light-emitting element. The first sub-light-emitting element is multiplexed as a light-sensing element and configured to sense reflected light reflected from an object contacting or adjacent to the light-sensing element and generate a sensing signal according to the sensed reflected light. The light-blocking element has a footprint on the substrate adjacent to and surrounding a footprint of the light-sensing element on the substrate to block light other than the reflected light from entering the light-sensing element.

[0007] In embodiments of the present disclosure, the light-emitting element further includes a second sub-light-emitting element. The second sub-light-emitting element is only used for light emission.

[0008] In embodiments of the present disclosure, the first sub-light-emitting element is located in a blue pixel, and the second sub-light-emitting element is located in a red pixel, a green pixel, and a blue pixel.

[0009] In embodiments of the present disclosure, the first sub-light-emitting element is located in a red pixel, and the second sub-light-emitting element is located in a red pixel, a green pixel, and a blue pixel.

[0010] In embodiments of the present disclosure, the first sub-light-emitting element is located in a green pixel, and the second sub-light-emitting element is located in a red pixel, a green pixel, and a blue pixel.

[0011] In embodiments of the present disclosure, the light blocking element has a reflectivity higher than a transmissivity.

[0012] In embodiments of the present disclosure, the pixel array is arranged along a first direction and a second direction, and the pixels containing the light sensing elements are spaced apart along the first direction and / or the second direction.

[0013] In embodiments of the present disclosure, along the first direction or the second direction, two adjacent pixels containing the light sensing elements are spaced apart by K pixels not containing the light sensing elements, where K is a positive integer greater than or equal to 2.

[0014] In embodiments of the present disclosure, along the first direction, two adjacent pixels containing the light sensing elements are spaced apart by two pixels, and along the second direction, two adjacent pixels containing the light sensing elements are adjacent without being spaced apart.

[0015] In embodiments of the present disclosure, along the first direction and the second direction, two adjacent pixels containing the light sensing elements are spaced apart by two pixels.

[0016] In embodiments of the present disclosure, the light blocking element is adjacent to and surrounds the light sensing element, and the display substrate further comprises a pixel defining layer on the substrate and arranged between the second sub-light emitting element, the light sensing element, and the light blocking element.

[0017] In embodiments of the present disclosure, the light blocking element comprises a first sub-structure arranged on the substrate in the same layer as the pixel defining layer, and the first sub-structure has the same material as the pixel defining layer.

[0018] In embodiments of the present disclosure, the light blocking element comprises a second sub-structure arranged on the first sub-structure away from the substrate side, and the second sub-structure comprises a metal layer.

[0019] In embodiments of the present disclosure, the display substrate further comprises a light shielding layer arranged on the second sub-light emitting element and the light sensing element away from the substrate side. The light shielding layer comprises a first opening and a second opening. The light blocking element is arranged in the same layer as the light shielding layer and has the same material as the light shielding layer. The first opening exposes the light sensing element. The second opening exposes the second sub-light emitting element.

[0020] In embodiments of the present disclosure, the first opening is filled with a quantum dot material and a color filter material. The second opening is filled with a photonic crystal material or a scattering particle material.

[0021] In embodiments of the present disclosure, the first direction extends along a width direction of the first sub-light emitting element. A normal projection of the light blocking element on the substrate overlaps a normal projection of the first sub-light emitting element on the substrate along the first direction.

[0022] In embodiments of the present disclosure, a size of the first opening along the first direction is smaller than a size of the light sensing element.

[0023] According to a second aspect of the present disclosure, a driving circuit for a pixel is provided. The pixel is located on a substrate. The pixel includes a light emitting element and a light blocking element. The light emitting element is located on the substrate. The light emitting element includes a first sub-light emitting element. The first sub-light emitting element is multiplexed as a light sensing element and configured to sense reflected light reflected from an object contacting or adjacent to the light sensing element and generate a sensing signal according to the sensed reflected light. The light blocking element has a positive projection on the substrate adjacent to and surrounding a positive projection of the light sensing element on the substrate to block light other than the reflected light from entering the light sensing element. The driving circuit includes a first transistor to an eighth transistor, a first capacitor and the first sub-light emitting element. A control electrode of the first transistor is coupled with a previous stage gate driving signal terminal, a first electrode of the first transistor is coupled with a reference voltage terminal, and a second electrode of the first transistor is coupled with a first node. A control electrode of the second transistor is coupled with a gate driving signal terminal, a first electrode of the second transistor is coupled with the first node, and a second electrode of the second transistor is coupled with a second node. A control electrode of the third transistor is coupled with the first node, a first electrode of the third transistor is coupled with the second node, and a second electrode of the third transistor is coupled with a third node. A control electrode of the fourth transistor is coupled with an enable signal terminal, a first electrode of the fourth transistor is coupled with a high voltage terminal, and a second electrode of the fourth transistor is coupled with the third node. A control electrode of the fifth transistor is coupled with a gate driving voltage terminal, a first electrode of the fifth transistor is coupled with a data signal terminal, and a second electrode of the fifth transistor is coupled with the third node. A control electrode of the sixth transistor is coupled with the enable signal terminal, a first electrode of the sixth transistor is coupled with the second node, and a second electrode of the sixth transistor is coupled with a fourth node. A control electrode of the seventh transistor is coupled with a scan signal terminal, a first electrode of the seventh transistor is coupled with the fourth node, and a second electrode of the seventh transistor is coupled with a fifth node. A control electrode and a first electrode of the eighth transistor are coupled with the reference voltage terminal, and a second electrode of the eighth transistor is coupled with the fifth node. A first plate of the first capacitor is coupled with a high voltage terminal, and a second plate of the first capacitor is coupled with the first node N1. A first end of the first sub-light emitting element is coupled with the fourth node, and a second end of the first sub-light emitting element is coupled with a low voltage terminal. The fifth node is coupled with a reading signal line.

[0024] According to a third aspect of the present disclosure, a driving circuit for a pixel is provided. The pixel is located on a substrate. The pixel includes a light emitting element and a light blocking element. The light emitting element is located on the substrate. The light emitting element includes a first sub-light emitting element. The first sub-light emitting element is multiplexed as a light sensing element and configured to sense reflected light reflected from an object contacting or adjacent to the light sensing element and generate a sensing signal according to the sensed reflected light. The light blocking element has a normal projection on the substrate adjacent to and surrounding a normal projection of the light sensing element on the substrate to block light other than the reflected light from entering the light sensing element. The driving circuit includes a first transistor to a sixth transistor, a first capacitor and the first sub-light emitting element. A control electrode of the first transistor is coupled with a scan signal terminal, a first electrode of the first transistor is coupled with a first node, and a second electrode of the first transistor is coupled with a second node, wherein the second node is coupled with a read signal line. A control electrode of the second transistor is coupled with a third node, a first electrode of the second transistor is coupled with a high voltage terminal, and a second electrode of the second transistor is coupled with the first node. A control electrode of the third transistor is coupled with a gate driving voltage terminal, a first electrode of the third transistor is coupled with a data signal terminal, and a second electrode of the third transistor is coupled with the third node N3. A control electrode of the fourth transistor is coupled with a previous stage gate driving signal terminal, a first electrode of the fourth transistor is coupled with the first node, and a second electrode of the fourth transistor is coupled with the second node. A control electrode of the fifth transistor is coupled with the previous stage gate driving signal terminal, a first electrode of the fifth transistor is coupled with a first low voltage terminal, and a second electrode of the fifth transistor is coupled with the first node. A control electrode of the sixth transistor is coupled with the previous stage gate driving signal terminal, a first electrode of the sixth transistor is coupled with the third node, and a second electrode of the sixth transistor is coupled with a second low voltage terminal. A first plate of the first capacitor is coupled with the high voltage terminal, and a second plate of the first capacitor is coupled with the third node. One end of the first sub-light emitting element is coupled with the first node, and a second end of the first sub-light emitting element is coupled with the second low voltage terminal.

[0025] According to a fourth aspect of the present disclosure, a display device is provided. The display device includes the display substrate according to any one of the first aspect.

[0026] Further aspects and ranges are apparent from the description provided herein. It should be understood that the various aspects of the present application can be practiced alone or in combination with one or more other aspects. It should also be understood that the description and specific examples herein are intended to be illustrative only and are not intended to limit the scope of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] The drawings described herein are for the purpose of illustrating selected embodiments and are not necessarily all the possible implementations, and are not intended to limit the scope of the present application, wherein:

[0028] FIG. 1 shows a photoelectric characteristic curve diagram of a Micro-LED in a reverse bias state.

[0029] FIG. 2 illustrates a top view of a display substrate for light sensing according to an embodiment of the present disclosure;

[0030] FIG. 3 illustrates a top view of a display substrate for light sensing according to another embodiment of the present disclosure;

[0031] FIG. 4 illustrates a top view of a display substrate for light sensing according to yet another embodiment of the present disclosure;

[0032] FIG. 5 illustrates a cross-sectional view of the display substrate in FIG. 2 along a section line EE’ according to an embodiment of the present disclosure;

[0033] FIG. 6 illustrates a partially enlarged view of FIG. 5 according to an embodiment of the present disclosure;

[0034] FIG. 7 illustrates a cross-sectional view of the display substrate in FIG. 3 along a section line FF’ according to an embodiment of the present disclosure;

[0035] FIG. 8 illustrates a schematic view of a stack of light blocking elements according to an embodiment of the present disclosure;

[0036] FIG. 9 illustrates a cross-sectional view of the display substrate in FIG. 3 along a section line GG’ according to an embodiment of the present disclosure;

[0037] FIG. 10 illustrates a schematic view of a display substrate for light sensing according to still another embodiment of the present disclosure;

[0038] FIG. 11 illustrates a schematic view of a pixel array according to an embodiment of the present disclosure;

[0039] FIG. 12 illustrates a schematic view of a pixel array according to another embodiment of the present disclosure;

[0040] FIG. 13 illustrates a pixel driving circuit for a pixel including a light sensing element according to an embodiment of the present disclosure;

[0041] FIG. 14 illustrates a pixel driving circuit for a pixel not including a light sensing element according to an embodiment of the present disclosure;

[0042] FIG. 15 illustrates a timing diagram for the pixel driving circuit illustrated in FIG. 13 according to an embodiment of the present disclosure;

[0043] FIG. 16 illustrates a pixel driving circuit for a pixel including a light sensing element according to another embodiment of the present disclosure;

[0044] FIG. 17 illustrates a pixel driving circuit for a pixel not including a light sensing element according to another embodiment of the present disclosure;

[0045] FIG. 18 illustrates a pixel driving circuit for a group of pixels according to an embodiment of the present disclosure;

[0046] FIG. 19 illustrates a timing diagram for the pixel driving circuit shown in FIG. 16, according to an embodiment of the present disclosure;

[0047] FIG. 20 illustrates a flowchart of a process of preparing a display substrate for light sensing, according to an embodiment of the present disclosure; and

[0048] FIG. 21 illustrates a structural schematic diagram of a display apparatus, according to an embodiment of the present disclosure.

[0049] Throughout the drawings, like reference numerals indicate like parts or features throughout the several views. The drawings are not drawn to scale, but rather emphasis is placed upon illustrating the functional principles of the various elements. DETAILED DESCRIPTION

[0050] First, it is to be noted that, unless otherwise explicitly indicated herein, the singular forms "a," "an," and "the" include plural referents, and vice versa. Thus, when referring to a singular form, the plural form is generally included. Similarly, the words "comprise," "comprises," and "comprising" are to be interpreted inclusively rather than exclusively. Likewise, the terms "include," "including," and "has," "have," "having," or variants thereof are intended to be inclusive rather than mutually exclusive. Where the term "example" is used, it is merely used to introduce an example, and is not to be interpreted as a limitation on the scope of the disclosure.

[0051] In addition, it is to be noted that, when introducing elements of the present disclosure and embodiments thereof, the articles "a," "an," and "the" and "said" are intended to mean that there are one or more of the elements; the meaning of "or" is that of inclusion, unless otherwise explicitly indicated herein; and the words "comprise," "comprises," "comprising," "contain," "contains," "containing," and "have," "has," "having" or variants thereof are intended to be inclusive, in that they specify the presence of stated features, integers, steps, processes, acts, or the like, but do not preclude the presence or addition of one or more other features, integers, steps, processes, acts, or the like.

[0052] The type of light emitting diode, LED, or Micro-LED is not particularly limited in the present disclosure, for example, an LED having a quantum well junction, an LED having a columnar structure, an LED having a double heterojunction, etc. can be employed. The LED can be a structure that is miniaturized to the order of hundreds of micrometers, for example, the area of the region from which light is emitted by the light emitting diode is preferably 1 mm2or less, more preferably 10,000 μm2or less, further preferably 3,000 μm2or less, further preferably 700 μm2or less, and can even be 200 μm2or less.

[0053] As described above, the function of recognizing the motion or texture of an operation object on the screen can be implemented by multiplexing the LEDs. The micro-LED display device includes micro-scale semiconductor light emitting units, i.e., LEDs, arranged in an array. In the display device in which the LEDs are multiplexed, the LEDs can emit light, e.g., red, green, and blue light, when the LEDs are in a forward-biased state. In an embodiment of the disclosure, the light emitting elements in the pixel array can respectively emit red, green, and blue light. Specifically, the LEDs can be combined with a wavelength conversion material such as a phosphor to emit blue, green, or red light, thereby also emitting white or ultraviolet light. The phosphor can be stacked or coated on at least one surface of a light-transmissive substrate or each LED, and the phosphor can include at least one type of wavelength conversion material that can be excited by light emitted by each LED to emit light having a wavelength different from that of light emitted by the semiconductor layer stack. This can allow the wavelength of light to be controlled, so that various colors of light can be emitted. A display substrate having such LEDs will be described in detail below with reference to FIG. 7, and thus a detailed description thereof will not be repeated here.

[0054] In another embodiment of the disclosure, the light emitting elements in the pixel array can emit only blue light, and then a quantum dot material is used to implement conversion of blue light to red light and blue light to green light. There is no particular limitation on the material constituting the quantum dot. The quantum dot has a larger band gap as its size is smaller, and thus its size is appropriately adjusted to obtain light of a desired wavelength. For example, for an LED that emits blue light, as the size of the quantum dot becomes smaller, the blue light can be shifted to the high-energy side of the spectrum after passing through the quantum dot, and thus the emission wavelength thereof can be adjusted in the wavelength region of the spectrum covering the ultraviolet region, the visible light region, and the infrared region by changing the size of the quantum dot. The size (diameter) of the quantum dot is, for example, 0.5 nm or more and 20 nm or less, and is preferably 1 nm or more and 10 nm or less. The quantum dot has a narrower emission spectrum as its size distribution is smaller, and thus light having a high color purity can be obtained. In addition, there is no particular limitation on the shape of the quantum dot, and the quantum dot can be spherical, rod-shaped, disc-shaped, or another shape. A quantum rod that is a rod-shaped quantum dot has a function of emitting light having directivity. When color conversion is implemented using a quantum dot, a wavelength selection is generally implemented in combination with a filter. The material of the coloring layer can include a metal material, a resin material, a resin material including a pigment or a dye, or the like. A display substrate having such LEDs will be described in detail below with reference to FIG. 5, and thus a detailed description thereof will not be repeated here.

[0055] When the LED is in a reverse bias state, it can detect light incident on the LED as a photoelectric sensor. The LED in the reverse bias state senses light reflected from an operation object and generates a sensing signal based on the reflected light, and then a processing component in the display device can detect the motion or texture of the operation object, such as the fingerprint of a user's finger, according to the sensing signal. The electrical characteristics of the LED in the reverse bias state are described below with reference to FIG. 1.

[0056] FIG. 1 shows a photoelectric characteristic curve of a Micro-LED in a reverse bias state. In the experiment, the Micro-LED is sapphire-based, with an area of 186 μm 2 . FIG. 1 shows the curve of the bias voltage and the current flowing through the Micro-LED in a dark environment and a 100 lx environment, respectively. As shown in FIG. 1, when the bias voltage is -1.5 V, that is, the reverse bias voltage is 1.5 V, the order of magnitude of the current flowing through the Micro-LED in the 100 lx environment is about 10 -9 , and the order of magnitude of the current flowing through the Micro-LED in the dark environment is about 10 -13 . That is, there is at least a difference of 3 orders of magnitude between them. Therefore, it can be concluded that the Micro-LED in the reverse bias state has a light-sensitive optical characteristic. Therefore, this optical characteristic can be used, and the pixel driving circuit is combined with a sensing current detection circuit to realize the conversion of the sensed light brightness to the current, and realize the function of light touch or fingerprint detection according to the detected current. Generally, the light sensed by the LED includes ambient light from the outside environment in addition to the reflected light as the target, which will affect the signal-to-noise ratio of the sensing signal, and then affect the accuracy and sensitivity of the result.

[0057] In order to reduce the light other than the reflected light into the LED in the reverse bias state, ensure the accuracy and sensitivity of the detection, the embodiments of the present disclosure further set a light-blocking element near the LED multiplexed as a photoelectric sensor to block the ambient light into the LED multiplexed as a photoelectric sensor, thereby improving the signal-to-noise ratio of the detection signal, improving the accuracy and sensitivity of the detection.

[0058] Embodiments of the present disclosure provide a display substrate for light sensing. The embodiments of the present disclosure and examples thereof are described in detail below with reference to the accompanying drawings.

[0059] FIG. 2 shows a top view of a display substrate for light sensing according to an embodiment of the present disclosure. As shown in FIG. 2, the display substrate 5 includes a display area AA, a substrate 100, a light sensing element S, and a light blocking element Ba. The display area AA includes red pixels R, green pixels G, and blue pixels B arranged in an array. The pixel array is arranged along a first direction and a second direction. As shown in FIG. 1, the first direction is along the X axis, and the second direction is along the Y axis. The width direction of the pixels is the first direction, and the length direction of the pixels is the second direction. In other embodiments of the present disclosure, the pixels arranged in an array can have other configurations. One configuration is that the width direction of the pixels is the second direction, and the length direction of the pixels is the first direction. Another configuration is that the length direction and the width direction of the pixels of different colors are inconsistent. Yet another configuration is that the pixels in the same row or the same column are not center-aligned in the first direction or the second direction. This will be described in detail below with reference to FIGS. 11 and 12, and will not be described here again.

[0060] In an embodiment of the present disclosure, a pixel includes a light emitting element and a light blocking element Ba. The light emitting element includes a first sub-light emitting element S. The first sub-light emitting element S is multiplexed as the light sensing element S and is configured to sense reflected light reflected from an object contacting or adjacent to the light sensing element S, and to generate a sensing signal according to the sensed reflected light. In an embodiment of the present disclosure, the sensed object can be a finger of a user using the display substrate. The generated sensing signal can be used to identify a fingerprint of the finger of the user. In other embodiments of the present disclosure, the sensed object can be a stylus or other object used for touch or near touch operation on the display device.

[0061] The light emitting element further includes a second sub-light emitting element L. The second sub-light emitting element L is used only for light emission. In an embodiment of the present disclosure, the light sensing element S can be located only in pixels of one color. As shown in FIG. 2, the light sensing element S is located only in the blue pixels B. In other embodiments of the present disclosure, the light sensing element S is located in the red pixels R. Alternatively, the light sensing element S can be located in the green pixels R. In other embodiments of the present disclosure, the light sensing element S can be located in pixels of different colors. Alternatively, the light sensing element S can be located in the red pixels R or the green pixels G. In other embodiments of the present disclosure, the light sensing element S can be located in pixels of different colors, for example, in the red pixels R and the blue pixels B, or in the green pixels G and the blue pixels B, or in the red pixels R and the green pixels B, or in the red pixels R, the green pixels G, and the blue pixels B.

[0062] In implementations of the present disclosure, the pixels containing the light sensing elements S are spaced apart in the first direction X and / or the second direction Y. In embodiments, two adjacent pixels containing the light sensing elements S are spaced apart by two pixels not containing the light sensing elements S in the X direction. In the first direction X and the second direction Y, two adjacent pixels containing the light sensing elements S are spaced apart by K pixels not containing the light sensing elements S, where K is a positive integer greater than or equal to 2. As shown in FIG. 2, in the first direction X, two adjacent blue pixels B containing the light sensing elements S are spaced apart by two pixels: one red pixel R and one green pixel G. In the second direction Y, two adjacent blue pixels B containing the light sensing elements S are adjacent and not spaced apart. In other embodiments of the present disclosure, in the second direction Y, two adjacent blue pixels B containing the light sensing elements S are spaced apart by two pixels: one red pixel R and one green pixel G. As shown in FIG. 2, in the same column, two adjacent blue pixels B containing the light sensing elements S are spaced apart by two pixels: two blue pixels B. Although not shown, it can be inferred that in the same row, two adjacent blue pixels B containing the light sensing elements S are spaced apart by eight pixels: three pixels R, three pixels G, and two pixels B (not containing the light sensing elements S). It should be understood that the spacing between the pixels containing the light sensing elements S can be set according to the sensitivity required in practice or the texture characteristics of the back-sensed object, for example, the distance between the ridges of a finger print.

[0063] In embodiments of the present disclosure, the light blocking element Ba has a footprint on the substrate 100 that is adjacent to and surrounds the footprint of the light sensing element S on the substrate 100 to block light other than reflected light from entering the light sensing element S. As shown in FIG. 2, in the X direction, the footprint of the light blocking element Ba on the substrate 100 overlaps with the footprint of the light sensing element S on the substrate 100. This overlap arrangement can effectively reduce light having a large incident angle, and thus can further reduce ambient light from entering the light sensing element S and improve the collimation of the reflected light entering the light sensing element S, thereby improving the accuracy of object recognition. The light blocking element Ba will be described in detail below with reference to FIGS. 5, 6, and 8.

[0064] In embodiments of the present disclosure, the light blocking element Ba has a higher reflectivity than transmissivity. In embodiments, the light blocking element Ba can include an organic light-impermeable material. In other embodiments, the light blocking element Ba can include an organic light-permeable material and a light-impermeable highly reflective metal layer on the organic light-permeable material. In embodiments of the present disclosure, the metal layer can include Ag or Al. This arrangement of a material having low transmissivity and high reflectivity enables the light blocking element Ba to block ambient light (e.g., light emitted by other pixels in the surrounding) from entering the light sensing element S. The light blocking element Ba will be described in detail below with reference to FIGS. 5, 6, and 8.

[0065] As shown in FIG. 2, one pixel group G includes one red pixel R, one green pixel G, and one blue pixel B. In other embodiments of the present disclosure, one pixel group G includes one red pixel R, one green pixel G, and two blue pixels B. Among them, one blue pixel B contains a photosensitive element S.

[0066] FIG. 3 shows a top view of a display substrate for light sensing according to another embodiment of the present disclosure. As shown in FIG. 3, the display substrate 10 is different from the display substrate 5 in that the orthogonal projection of the light-blocking element Ba on the substrate 100 only surrounds the orthogonal projection of the pixel containing the photosensitive element S on the substrate 100, and the orthogonal projection of the light-blocking element Ba on the substrate 100 does not overlap with the orthogonal projection of the photosensitive element S on the substrate 100. In embodiments of the present disclosure, the photosensitive element S can be located only in pixels of one color. As shown in FIG. 3, the photosensitive element S is located only in the blue pixel B. The photosensitive element S is located only in the blue pixel B. In other embodiments of the present disclosure, the photosensitive element S is located in the red pixel R. Alternatively, the photosensitive element S can be located in the green pixel R. In other embodiments of the present disclosure, the photosensitive element S can be located in pixels of different colors. Alternatively, the photosensitive element S can be located in the red pixel R or the green pixel G. In other embodiments of the present disclosure, the photosensitive element S can be located in pixels of different colors, such as in the red pixel R and the blue pixel B, or in the green pixel G and the blue pixel B, or in the red pixel R and the green pixel B, or in the red pixel R, the green pixel G, and the blue pixel B.

[0067] FIG. 4 shows a top view of a display substrate for light sensing according to yet another embodiment of the present disclosure. In embodiments of the present disclosure, the display substrate 15 is different from the display substrate 5 in that the orthogonal projection of the light-blocking element Ba on the substrate 100 surrounds the orthogonal projection of the pixel containing the photosensitive element S on the substrate 100 and extends in the first direction X and the second direction Y. As shown in FIG. 4, around the orthogonal projection of the pixel containing the photosensitive element S on the substrate 100, there is a square orthogonal projection of the light-blocking element Ba on the substrate 100. In embodiments, each side of the square orthogonal projection is along the row direction (the first direction X) and the column direction (the second direction Y) of the pixel. Each side of the square orthogonal projection extends along the row direction or the column direction.

[0068] FIG. 5 shows a cross-sectional view of the display substrate in FIG. 2 along the section line EE’ according to an embodiment of the present disclosure. The display substrate 20 includes light-emitting elements disposed on the substrate 100. As shown in FIG. 5, the light-emitting elements are all blue LEDs. Among them, one blue LED is multiplexed as the photosensitive element S. In other embodiments of the present disclosure, the light-emitting elements can include red LEDs, green LEDs, and blue LEDs. This will be shown in FIG. 7, which will not be described here again.

[0069] The display substrate 20 further comprises a filling layer 110 disposed on the substrate 100 for filling between the light emitting elements L and the light sensing element S. The material of the filling layer 110 can be an organic light blocking material.

[0070] The display substrate 20 further comprises a light blocking layer 120 disposed on the second sub light emitting element L and the light sensing element S away from the substrate 100 side. The light blocking layer 120 comprises a first opening O1 and a second opening O2. The first opening O1 exposes the light sensing element S, and the second opening O2 exposes the light emitting element L. The light blocking element Ba is disposed in the same layer as the light blocking layer 120 and has the same material as the light blocking layer 120. In the embodiments of the present disclosure, the material in the light blocking layer 120 is the same as the material in the filling layer 110, and the material in the light blocking element Ba is the same as the material of the light blocking layer 120, which is a black organic light blocking material. In the first direction X, the size of the first opening O1 is smaller than the size of the light sensing element S. Therefore, the orthographic projection of the light blocking element Ba on the substrate 100 overlaps with the orthographic projection of the first sub light emitting element S on the substrate 100 in the first direction X. In the first direction X, the size of the second opening O2 is greater than the size of the light emitting element L.

[0071] Alternatively, in other embodiments of the present disclosure, the material in the light blocking element Ba can be inconsistent with the material of the light blocking layer 120. The light blocking element Ba can comprise a first substructure and a second substructure disposed on the first substructure away from the substrate side. The stacked structure of the light blocking element will be described in detail below with reference to FIG. 8.

[0072] In the first opening O1, quantum dot materials QD and color filter materials CF of different compositions are disposed to convert the light from the light emitting element (blue LED) into red light and green light, and filter the red light and green light respectively.

[0073] In the second opening O2, scattering particles and a blue filter are disposed. The blue filter can allow only the blue light in the reflected light from the finger to enter the light sensing element S.

[0074] Additionally, the display substrate 20 further comprises an encapsulation layer 130 between the light blocking layer 120 and the filling layer 110. The encapsulation layer 130 is used to encapsulate all the light emitting elements.

[0075] FIG. 6 shows a zoomed-in view of the area marked by the white oval in FIG. 5, according to an embodiment of the present disclosure. FIG. 6 shows a zoomed-in view of the area marked by the white oval in FIG. 5. As shown in FIG. 6, the first opening O1 has a dimension d1 in the first direction X. In an embodiment of the present disclosure, the distance d1 is 5 pm. The photosensitive element S has a dimension d2 in the first direction X. In an embodiment of the present disclosure, the width d2 is 20 pm. The light-blocking element Ba has a thickness d3 in the third direction Z. In an embodiment of the present disclosure, the thickness d3 is 8 pm. In the third direction Z, the distance between the light-blocking element Ba and the photosensitive element S is d4. In an embodiment of the present disclosure, the distance d4 is the same as the distance d1, for example, 5 pm. Although not shown, the pixel has a dimension of 30 pm in the second direction Y. As described above, such a narrow-slit design can effectively reduce light rays with large incident angles, which can further reduce ambient light incident on the photosensitive element S and improve the collimation of reflected light incident on the photosensitive element S, thereby improving the signal-to-noise ratio of the sensed signal and improving the accuracy of fingerprint recognition. Those skilled in the art should understand that the specific values should include errors caused by manufacturing processes and the like.

[0076] FIG. 7 shows a cross-sectional view of the display substrate in FIG. 3 along the section line FF’ according to an embodiment of the present disclosure. The display substrate 25 includes light-emitting elements. As shown in FIG. 7, the light-emitting elements include a red LED RL, a green LED GL, and a blue LED BL. The blue LED BL is multiplexed as the photosensitive element S. As previously described, in other embodiments of the present disclosure, the photosensitive element S can be multiplexed as an LED of one other color, two colors, or three colors. The light-blocking element Ba is disposed along the X direction on both sides of the pixel of the photosensitive element S. In an embodiment of the present disclosure, the material in the light-blocking element Ba includes an organic light-blocking material.

[0077] The display substrate 25 further includes a pixel defining layer 140 on the substrate 100 and between the second sub-light-emitting elements (including the red LED RL, the green LED GL, and the blue LED BL), the photosensitive element S, and the light-blocking element Ba. The pixel defining layer 140 can include an organic light-transmitting material, such as a transparent resin material or polyethylene, etc.

[0078] In other embodiments of the present disclosure, the light-blocking element Ba can be a laminated structure, which is described below with reference to FIG. 8.

[0079] Figure 8 shows a schematic view of a stack of light-blocking elements according to an embodiment of the present disclosure. As shown in Figure 8, the light-blocking element Ba includes a first sub-structure P1 and a second sub-structure P2 disposed on the first sub-structure P1 away from the substrate 100 side. The first sub-structure P1 is disposed in the same layer as the pixel defining layer 140 (not shown) and has the same material as the pixel defining layer 140, for example, an organic transparent material. The organic transparent material can include a transparent resin material or polyethylene, etc. The second sub-structure P2 includes a material with high reflectivity and low transmissivity, preferably a non-transparent material with high reflectivity. In an embodiment of the present disclosure, the second sub-structure P2 is a metal layer. The metal layer includes Ag or Al. The thickness of the metal layer can be 0.1 μm.

[0080] The cross-sectional view of the display substrate 15 along the section line HH' in Figure 4 is consistent with the cross-sectional view of the display substrate 10 along the section line FF' in Figure 3, and thus will not be described again here.

[0081] In an embodiment of the present disclosure, the display substrate further includes a backplane circuit layer between the substrate and the light-emitting element. The backplane circuit layer includes a pixel driving circuit. The display substrate including the backplane circuit layer with a detailed structure will be described in detail below with reference to Figure 8.

[0082] FIG. 9 shows a cross-sectional view of the display substrate in FIG. 3 along the section line GG' according to an embodiment of the present disclosure. As shown in FIG. 9, the display substrate 30 includes a substrate 100, a backplane circuit layer 200 located on the substrate 100, and a light-blocking element Ba located on the backplane circuit layer 200 away from the substrate 100 side. The backplane circuit layer 200 includes a buffer layer 205, a light shielding layer 210, an active layer 215, a first insulating layer 220, a first gate electrode layer 225, a second insulating layer 230, a second gate electrode layer 235, a third insulating layer 240, a first source-drain metal layer 245, a planarization layer 250, a second source-drain metal layer 255, a fourth insulating layer 260, and a positive and negative electrode layer 265 coupled with a light emitting device. The light emitting device is not shown for clarity.Specifically, the display substrate 30 includes: a substrate 100; a buffer layer 205 on the substrate 100; a light shielding layer 210 in the buffer layer 205, a portion of the active layer 215 as a channel region completely falls into the orthogonal projection of the light shielding layer 210 on the substrate 100; an active layer 215 on the buffer layer 205 away from the substrate 100 side; a first insulating layer 220 on the buffer layer 205 and the active layer 215 away from the substrate 100 side, the first insulating layer 220 has an opening exposing the active layer 215; a first gate electrode layer 225 on the first insulating layer 220 away from the substrate 100 side, the orthogonal projection of the first gate electrode layer 225 on the substrate 100 completely falls into the orthogonal projection of the active layer 215 on the substrate 100; a second insulating layer 230 on the first insulating layer 220 and the first gate electrode layer 225 away from the substrate 100 side, the second insulating layer 230 has an opening exposing the active layer 215 via the opening of the first insulating layer 220; a second gate electrode layer 235 on the second insulating layer 230 away from the substrate 100 side, the orthogonal projection of the second gate electrode layer 235 on the substrate 100 has an overlap with the orthogonal projection of the first gate electrode layer 225 on the substrate 100; a third insulating layer 240 on the second gate electrode layer 235 and the second insulating layer 230 away from the substrate 100 side, the third insulating layer 240 has an opening exposing the active layer 215 via the opening of the second insulating layer 230 and the opening of the first insulating layer 220; a first source / drain metal layer 245 on the third insulating layer 240 and in contact with the active layer 215 via the opening of the third insulating layer 240, the opening of the second insulating layer 230 and the opening of the first insulating layer 220; a planarization layer 250 on the first source / drain metal layer 245 and the third insulating layer 240 away from the substrate 100 side, the planarization layer 250 has an opening exposing the first source / drain metal layer 245; a second source / drain metal layer 255 on the planarization layer 250 away from the substrate 100 side, the second source / drain metal layer 255 is in contact with the first source / drain metal layer 245 via the opening of the planarization layer 250; a fourth insulating layer 260 on the planarization layer 250 and the second source / drain metal layer 255 away from the substrate 100 side, the fourth insulating layer 260 has an opening exposing the second source / drain metal layer 255; a positive / negative electrode layer 265 on the fourth insulating layer 260 away from the substrate 100 side, the positive / negative electrode layer 265 is in contact with the second source / drain metal layer 255 via the opening of the fourth insulating layer 260.

[0083] In an embodiment, the orthogonal projection of the light blocking element Ba on the substrate 100 generally falls in or has an overlap with the orthogonal projection of the metal wiring in the back plate circuit layer 200 on the substrate 100. The structure will be described below with reference to FIG. 10.

[0084] FIG. 10 shows a schematic diagram of a display substrate for light sensing according to yet another embodiment of the present disclosure. As shown in FIG. 10, the display substrate 35 includes a substrate 100, a backplane circuit layer 200 on the substrate 100, and a light blocking element Ba on the backplane circuit layer 200 away from the substrate 100 side. A metal wiring Wi is disposed in the backplane circuit layer 200. In an embodiment, the light blocking element Ba has a footprint on the substrate 100 that completely overlaps a footprint of the metal wiring Wi on the substrate 100. In other embodiments of the present disclosure, in an embodiment, the light blocking element Ba has a footprint on the substrate 100 that partially overlaps or falls within a footprint of the metal wiring Wi on the substrate 100. In an embodiment, the metal wiring Wi can be any one of the first gate electrode layer 225, the second gate electrode layer 235, the first source / drain metal layer 245, and the second source / drain metal layer 255 in FIG. 9. In other embodiments of the present disclosure, the metal wiring Wi can be disposed in any metal layer in the backplane circuit layer 200. Such a configuration in which the light blocking element Ba has a footprint on the substrate 100 that partially overlaps or falls within a footprint of the metal wiring Wi on the substrate 100 can serve to reduce reflectivity.

[0085] In addition, as shown in FIGS. 2-10, the pixel array is formed by red pixel columns, green pixel columns, and blue pixel columns being spaced apart in the second direction Y. In other embodiments of the present disclosure, the pixel array can include other configurations. FIG. 11 shows a schematic diagram of a pixel array according to an embodiment of the present disclosure. As shown in FIG. 11, the pixel array is formed by red pixel rows, green pixel rows, and blue pixel rows being spaced apart in the first direction X. FIG. 12 shows a schematic diagram of a pixel array according to another embodiment of the present disclosure. As shown in FIG. 12, the pixel array is formed by red pixel rows, green pixel rows, and blue pixel columns being spaced apart in the first direction X and the second direction Y. In FIGS. 11 and 12, the light sensing elements have similar structures and distributions as shown in FIGS. 2-7, and thus are not described again here.

[0086] The present disclosure also provides a pixel driving circuit for internally compensating a threshold voltage of a driving transistor while performing light sensing. The driving circuit is described in detail below with reference to FIGS. 13 and 14.

[0087] FIG. 13 shows a pixel driving circuit for a pixel containing a light sensing element, according to an embodiment of the present disclosure. Specifically, in an embodiment, the pixel is located on a substrate. The display substrate has a structure as shown in 2 to 12. The pixel includes: a light emitting element located on the substrate. The light emitting element includes a first sub light emitting element that is multiplexed as a light sensing element and configured to sense reflected light reflected from an object contacting or adjacent to the light sensing element and generate a sensing signal according to the sensed reflected light; and a light blocking element whose orthogonal projection on the substrate is adjacent to and surrounds the orthogonal projection of the light sensing element on the substrate to block light other than the reflected light from entering the light sensing element. The pixel driving circuit 50 includes eight transistors T1-T8, one capacitor C1, and one light emitting element L. In an embodiment, the light emitting element L is multiplexed as a light sensing element S. As shown in FIG. 13, the control electrode of the first transistor T1 is coupled with the gate driving signal end Gate(n-1) for the pixel driving circuit of the previous row, the first electrode of the first transistor T1 is coupled with the reference voltage end REF, and the second electrode of the first transistor T1 is coupled with the first node N1. The voltage from the reference voltage end REF is smaller than the voltage from the low voltage end VSS, which is smaller than the voltage from the high voltage end Vdd. The control electrode of the second transistor T2 is coupled with the gate driving signal end Gate(n), the first electrode of the second transistor T2 is coupled with the first node N1, and the second electrode of the second transistor T2 is coupled with the second node N2. The control electrode of the third transistor T3 is coupled with the first node N1, the first electrode of the third transistor T3 is coupled with the second node N2, and the second electrode of the third transistor T3 is coupled with the third node N3. The control electrode of the fourth transistor T4 is coupled with the enable signal end EM(n), the first electrode of the fourth transistor T4 is coupled with the high voltage end Vdd, and the second electrode of the fourth transistor T4 is coupled with the third node N3. The control electrode of the fifth transistor T5 is coupled with the gate driving voltage end Gate(n), the first electrode of the fifth transistor T5 is coupled with the data signal end Data, and the second electrode of the fifth transistor T5 is coupled with the third node N3. The control electrode of the sixth transistor T6 is coupled with the enable signal end EM(n), the first electrode of the sixth transistor T6 is coupled with the second node N2, and the second electrode of the sixth transistor T6 is coupled with the fourth node N4. The control electrode of the seventh transistor T7 is coupled with the scan signal end Scan(n), the first electrode of the seventh transistor T7 is coupled with the fourth node N4, and the second electrode of the seventh transistor T7 is coupled with the fifth node N5. The control electrode and the first electrode of the eighth transistor T8 are coupled with the reference voltage end REF, and the second electrode of the eighth transistor T8 is coupled with the fifth node N5. The fifth node N5 is coupled with the read signal line RW. The first plate of the first capacitor C1 is coupled with the high voltage end Vdd, and the second plate of the first capacitor C1 is coupled with the first node N1. The light emitting element L (multiplexed as the light sensing element S) is coupled with the fourth node N4 and the low voltage end VSS.

[0088] In this embodiment, the first to eighth transistors T1 to T8 are PMOS transistors. In other embodiments of the present disclosure, the transistors can be other types.

[0089] FIG. 14 shows a pixel driving circuit for a pixel not containing a photosensitive element according to an embodiment of the present disclosure. The pixel driving circuit 60 shown in FIG. 14 includes six transistors T1 to T6, one capacitor C1, and one light emitting element L. The pixel driving circuit 60 is different from the pixel driving circuit 50 shown in FIG. 13 in that it lacks the two transistors T7 and T8 for outputting a sensing current, in addition to the fact that the light emitting element L is no longer multiplexed as a photosensitive element. In operation, the pixel driving circuit 60 no longer senses reflected light in the non-display phase. Except for the above difference, the pixel driving circuit is similar to the pixel driving circuit 50 shown in FIG. 13, and thus will not be described again here.

[0090] FIG. 15 shows a timing diagram for the pixel driving circuit shown in FIG. 13 according to an embodiment of the present disclosure. As shown in FIG. 15, for the display phase DP, in a first phase tl, the pixel driving circuit receives a low-level scan signal Vscan and a gate driving signal Vgate(n-1) for the previous row of pixel driving circuits, and the first transistor T1 is turned on. The seventh transistor T7 is turned on to reset one pole of the light emitting element L. In a second phase t2, the pixel driving circuit receives a low-level data signal Vdata and a gate driving signal Vgate(n), and the fifth transistor T5 is turned on to write the data signal Vdata to the third node N3, and the first capacitor C1 stores a voltage difference Vdata-Vth between the data signal and the threshold voltage Vth of the third transistor T3. In a third phase t3, the pixel driving circuit receives a low-level enable signal Vem, and the fourth transistor T4 and the sixth transistor T6 are turned on. The third transistor T3 remains turned on. The light emitting current I provided by the third transistor T3 to the light emitting element L can be calculated according to the following formula (1): I = K(VGS-Vth) 2 Formula (1)

[0091] wherein VGS represents the voltage difference between the control pole and the second pole of the third transistor T3, and the first capacitor C1 stores the voltage difference Vdata-Vth, thus, I = K(VGS-Vth)2 = K[(Vdd-VData+Vth)-Vdd-Vth]2 = K-VData 2

[0092] Therefore, the output current of the light emitting element L is independent of the threshold voltage Vth of the third transistor T3, and thus internal compensation of the threshold voltage of the third transistor T3 is completed.

[0093] For the non-display stage BP, the data signal Vdata and the scan signal Vscan at the low level are received, the seventh transistor T7 is turned on, and the current generated by the light-sensing element S (i.e., the light-emitting element L) sensing the reflected light from the finger is provided to the read signal line RW as a fingerprint recognition signal. Then, the fingerprint information is identified based on the read fingerprint recognition signal by the external processing component.

[0094] Further, other pixels not including the light-sensing element according to the present disclosure. This will be described below with reference to FIG. 15.

[0095] The present disclosure also provides a driving circuit that implements light sensing while externally compensating for the threshold voltage of a driving transistor. This will be described in detail below with reference to FIGS. 9 and 10.

[0096] FIG. 16 shows a pixel driving circuit for a pixel containing a photosensitive element according to another embodiment of the present disclosure. Specifically, in the embodiment, the pixel is located on a substrate. The display substrate has a structure as shown in 2 to 12. The pixel includes: a light emitting element located on the substrate. The light emitting element includes a first sub-light emitting element, which is multiplexed as a photosensitive element and configured to sense reflected light reflected from an object contacting or adjacent to the photosensitive element, and generate a sensing signal according to the sensed reflected light; and a light blocking element, whose orthographic projection on the substrate is adjacent to and surrounds the orthographic projection of the photosensitive element on the substrate, to block light other than the reflected light from entering the photosensitive element. The pixel driving circuit 70 includes first to sixth transistors T1-T6, a first capacitor C1, and a light emitting element L. In the embodiment, the light emitting element L is multiplexed as a photosensitive element S. As shown in FIG. 9, a control electrode of the first transistor T1 is coupled with a scan signal terminal Scan(n), a first electrode of the first transistor T1 is coupled with a first node N1, and a second electrode of the first transistor T1 is coupled with a second node N2. The second node N2 is coupled with a read signal line RW. A control electrode of the second transistor T2 is coupled with a third node N3, a first electrode of the second transistor T2 is coupled with a high voltage terminal Vdd, and a second electrode of the second transistor T2 is coupled with the first node N1. A control electrode of the third transistor T3 is coupled with a gate driving voltage terminal Gate(n), a first electrode of the third transistor T3 is coupled with a data signal terminal Data, and a second electrode of the third transistor T3 is coupled with the third node N3. A control electrode of the fourth transistor T4 is coupled with a gate driving signal terminal Gate(n-1) for a pixel driving circuit of a previous row, a first electrode of the fourth transistor T4 is coupled with the first node N1, and a second electrode of the fourth transistor T4 is coupled with the second node N2. A control electrode of the fifth transistor T5 is coupled with the gate driving signal terminal Gate(n-1) for the pixel driving circuit of the previous row, a first electrode of the fifth transistor T5 is coupled with a first low voltage terminal VGL, and a second electrode of the fifth transistor T5 is coupled with the first node N1. A control electrode of the sixth transistor T6 is coupled with the gate driving signal terminal Gate(n-1) for the pixel driving circuit of the previous row, a first electrode of the sixth transistor T6 is coupled with the third node N3, and a second electrode of the sixth transistor T6 is coupled with a second low voltage terminal VSS. A first plate of the first capacitor C1 is coupled with the high voltage terminal Vdd, and a second plate of the first capacitor C1 is coupled with the third node N3. The light emitting element L (multiplexed as the photosensitive element S) is coupled with the first node N1 and the second low voltage terminal VSS.

[0097] In the embodiment, the first to sixth transistors T1-T6 are NMOS transistors.

[0098] In addition, other pixels not containing a photosensitive element according to the present disclosure are described below with reference to FIG. 17.

[0099] Figure 17 shows a pixel driving circuit for a pixel not containing a photosensitive element according to another embodiment of the present disclosure. The pixel driving circuit 80 shown in Figure 17 includes three transistors T1-T3, one capacitor C1 and one light emitting element L. The pixel driving circuit is different from the pixel driving circuit shown in Figure 80 in that it lacks the three transistors T4, T5 and T6 for sensing current, in addition to the light emitting element L no longer being multiplexed as a photosensitive element. In operation, the pixel driving circuit no longer senses reflected light in the non-display phase. Except for the above differences, the pixel driving circuit 80 is similar to the pixel driving circuit shown in Figure 16, which will not be described again here.

[0100] The present disclosure also provides a connection of driving circuits for a group of pixels. The group of pixels includes pixels having photosensitive elements. This will be described below with reference to Figure 18.

[0101] Figure 18 shows a pixel driving circuit for a group of pixels according to an embodiment of the present disclosure. The group of pixels includes red, green and blue pixels. Among them, RL represents a light emitting element for a red pixel, such as a red LED. GL represents a light emitting element for a green pixel, such as a green LED. BL represents a light emitting element for a blue pixel, such as a blue LED. The light emitting element BL for a blue pixel is multiplexed as a photosensitive element. As mentioned before, other light emitting elements can also be multiplexed as photosensitive elements, which will not be described again here. As shown in Figure 18, the pixel driving circuit 90 for the group of pixels includes pixel driving circuits DC1, DC2 and DC3. The pixel driving circuit DC1 for the light emitting element RL has the same specific structure as the pixel driving circuit 80 shown in Figure 17 for the light emitting element GL, and the pixel driving circuit DC3 for the light emitting element Bl has the same specific structure as the pixel driving circuit 70 shown in Figure 16. The read signal lines RW in the pixel driving circuits DC1, DC2 and DC3 are the same signal line, and the data signal terminals Data are coupled to the same data signal line DW. Although not shown, other same signal terminals of the pixel driving circuits DC1, DC2 and DC3 can be coupled to the same signal line.

[0102] Fig. 19 shows a timing diagram for the pixel driving circuit shown in Fig. 16, according to an embodiment of the present disclosure. As shown in Fig. 19, for a display phase DP, at a first stage tl, the pixel driving circuit 90 receives a high level of the gate driving signal Vgate(n-1) for the pixel driving circuit of the previous row, the fourth transistor T4, the fifth transistor T5 and the sixth transistor T6 are turned on. The fifth transistor T5, which is equivalent to a resistor, provides a first low level voltage to the first node Nl. The fourth transistor T4 is turned on to provide a current generated by the reflected light from the finger sensed by the light sensing element S (i.e. the light emitting element L) to the read signal line RW as a fingerprint recognition signal. Then, the fingerprint information is identified based on the read fingerprint recognition signal via an external processing component. At a second stage t2, the pixel driving circuit 90 receives a high level of the gate driving signal Vgate(n). The third transistor T3 is turned on to provide the data signal Vdata to the third node N3. The first capacitor Cl stores a voltage difference between the high level voltage Vdd and the data signal Vdata. For a non-display phase BP, at a third stage t3, the pixel driving circuit 90 receives a high level of the gate driving signal Vgate(n-1) for the pixel driving circuit of the previous row, the gate driving signal Vgate(n) and the data signal Vdata. The data signal Vdata is a constant voltage. According to formula (1), the current at the drain of the second transistor T2 is related to its threshold voltage. The voltage signal of the first node Nl is provided to the read signal line RW as a compensation signal for the threshold voltage of the second transistor T2. Then, the data signal is compensated based on the read compensation signal via the processing component.

[0103] The present disclosure further provides a method for manufacturing the display substrate for light sensing. The method is described in detail below with reference to Figs. 11 and 12.

[0104] FIG. 20 shows a flowchart of a process of preparing a display substrate for light sensing according to an embodiment of the present disclosure. FIG. 20 shows a flowchart 1100 of a process of preparing display substrates 5 and 20. As shown in FIG. 20, at step S1, light emitting elements L are generated on a transition substrate 100’. The light emitting elements L are blue LEDs. In other embodiments of the present disclosure, the light emitting elements L generated on the transition substrate 100’ include red LEDs, green LEDs, and blue LEDs. In embodiments of the present disclosure, the light emitting elements L can be generated specifically through processes of transparent electrode bonding, substrate dissociation, etching, passivation, etc. At step S2, the light emitting elements L are transferred and closely packed on a substrate on which a backplane circuit layer (not shown) is formed. At step S3, a third medium layer 110 is filled between the light emitting elements L and a packaging layer 130 is disposed on the third medium layer 110. In embodiments of the present disclosure, the third medium layer 110 includes an organic non-light-transmissive material. At step S4, a second medium layer 120 is disposed on the packaging layer 130, and first openings O1, second openings O2, and light blocking elements Ba are formed by etching. In embodiments of the present disclosure, the light blocking elements Ba have a normal projection on the substrate 100 that overlaps a normal projection of the blue LEDs (light sensing elements S) on the substrate 100. The second medium layer 120 can include an organic non-light-transmissive material and a metal layer disposed thereon. In other embodiments of the present disclosure, the second medium layer 120 can be formed of a laminated structure including an organic light-transmissive material and a metal layer disposed thereon. At step S4, after the first structure of the first openings O1, the second openings O2, and the light blocking elements is formed by etching, a conformal layer is disposed at step S5, a quantum dot material QD is disposed in the first openings, and scattering particles are disposed in the second openings. In the first openings and the second openings, a filter material is disposed on the quantum dot material and the scattering particles to form a color filter CF.

[0105] Alternatively, in other embodiments of the present disclosure, in a method of preparing a display substrate (e.g., display substrate 25) for light sensing, at step S3, light blocking elements Ba are disposed around the light emitting elements L that are multiplexed as light sensing elements S. Similar to the above, the light blocking elements Ba can include an organic non-light-transmissive material or a laminated material of an organic light-transmissive material and a metal layer. In embodiments of the present disclosure, the light blocking elements Ba can be disposed on a substrate on which a backplane circuit layer (not shown) is formed, and then a packaging layer 130 is formed. Alternatively, in other embodiments of the present disclosure, the light blocking elements Ba can be disposed on the packaging layer 130, and then the packaging layer 130 on which the light blocking elements Ba are formed is aligned and bonded with a substrate on which the light emitting elements L are formed. At step S4, a second medium layer 120 is disposed on the packaging layer 130, and first openings O1 and second openings O2 are formed by etching.

[0106] FIG. 21 shows a structural schematic diagram of a display device according to an embodiment of the present disclosure. As shown in FIG. 21, the display device 2100 can include the display substrate 5 / 15 / 20 / 25 / 30 / 35 according to any embodiment of the present disclosure and / or the pixel driving circuit 50 or 70 according to any embodiment of the present disclosure.

[0107] The display device 2100 can be any product or component with display function, such as VR or AR display device, EVF, sight, FPV device, mobile phone, tablet computer, television, display, notebook computer, digital photo frame, navigator, etc.

[0108] The display device provided by the embodiments of the present disclosure has the same or similar beneficial effects as the display substrate provided by the foregoing embodiments of the present disclosure. Since the display substrate has been described in detail in the foregoing embodiments, it will not be described here.

[0109] The foregoing description of the embodiments has been provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the application. The various elements or features of a specific embodiment are generally not limited to the particular embodiment, but, where appropriate, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same can also be varied in many ways. Such variations cannot be considered as departing from the present application, and all such modifications are included within the scope of the present application.

Claims

1. A display substrate for light sensing, the display substrate comprising: a substrate; an array of pixels on the substrate, the pixels comprising: a light emitting element on the substrate, wherein the light emitting element comprises a first sub light emitting element, the first sub light emitting element is multiplexed as a light sensing element and configured to sense reflected light reflected from an object contacting or adjacent to the light sensing element and generate a sensing signal according to the sensed reflected light; and a light blocking element, a footprint of the light blocking element on the substrate is adjacent to and surrounds a footprint of the light sensing element on the substrate to block light other than the reflected light from entering the light sensing element. 2.The display substrate of claim 1, wherein, the light emitting element further comprises a second sub light emitting element, the second sub light emitting element is only used for light emitting. 3.The display substrate of claim 2, wherein, the first sub light emitting element is in a blue pixel, the second sub light emitting element is in a red pixel, a green pixel and a blue pixel. 4.The display substrate of claim 2, wherein, the first sub light emitting element is in a red pixel, the second sub light emitting element is in a red pixel, a green pixel and a blue pixel. 5.The display substrate of claim 2, wherein, the first sub light emitting element is in a green pixel, the second sub light emitting element is in a red pixel, a green pixel and a blue pixel. 6.The display substrate of claim 1, wherein, the light blocking element has a reflectivity higher than a transmittance. 7.The display substrate of claim 6, wherein, the array of pixels is arranged along a first direction and a second direction, pixels containing the light sensing element are spaced apart in the first direction and / or the second direction. 8.The display substrate of claim 7, wherein, in the first direction or the second direction, two adjacent pixels containing the light sensing element are spaced apart by K pixels not containing the light sensing element, wherein K is a positive integer greater than or equal to 2. 9.The display substrate of claim 8, wherein, in the first direction, two adjacent pixels containing the light sensing element are spaced apart by two pixels, in the second direction, two adjacent pixels containing the light sensing element are adjacent without being spaced apart. 10.The display substrate of claim 8, wherein, in the first direction and the second direction, two adjacent pixels containing the light sensing element are both spaced apart by two pixels. 11.The display substrate of claim 8, wherein, the light blocking element is adjacent to and surrounds the light sensing element, the display substrate further comprises a pixel defining layer on the substrate and arranged between the second sub light emitting element, the light sensing element and the light blocking element. 12.The display substrate of claim 11, wherein, the light blocking element comprises a first sub structure, the first sub structure is arranged on the substrate in the same layer as the pixel defining layer, the first sub structure has the same material as the pixel defining layer. 13.The display substrate of claim 12, wherein, the light blocking element comprises a second sub structure arranged on the first sub structure away from the substrate side, the second sub structure comprises a metal layer. 14.The display substrate of claim 8, further comprising a light shielding layer arranged on the second sub light emitting element and the light sensing element away from the substrate side, the light shielding layer comprises a first opening and a second opening, the light blocking element is arranged in the same layer as the light shielding layer and has the same material as the light shielding layer, and the first opening exposes the light sensing element and the second opening exposes the second sub light emitting element. 15.The display substrate of claim 14, wherein, the first opening is filled with a quantum dot material and a color filter material, and the second opening is filled with a photonic crystal material or a scattering particle material. 16.The display substrate of claim 14, wherein, The first direction extends along a width direction of the first sub-light emitting element, and a normal projection of the light blocking element on the substrate overlaps with a normal projection of the first sub-light emitting element on the substrate in the first direction. 17.The display substrate of claim 15, wherein, A size of the first opening along the first direction is smaller than a size of the light sensing element.

18. A drive circuit for a pixel, wherein, The pixel is located on a substrate, and the pixel includes: a light emitting element located on the substrate, wherein the light emitting element includes a first sub-light emitting element, the first sub-light emitting element is multiplexed as a light sensing element and is configured to sense reflected light reflected from an object contacting or adjacent to the light sensing element, and generate a sensing signal according to the sensed reflected light; and a light blocking element, a normal projection of the light blocking element on the substrate is adjacent to and surrounds a normal projection of the light sensing element on the substrate, so as to block light other than the reflected light from entering the light sensing element, the driving circuit includes a first transistor to an eighth transistor, a first capacitor and a first sub-light emitting element: A control electrode of the first transistor is coupled with a previous-stage gate driving signal terminal, a first electrode of the first transistor is coupled with a reference voltage terminal, and a second electrode of the first transistor is coupled with a first node; A control electrode of the second transistor is coupled with a gate driving signal terminal, a first electrode of the second transistor is coupled with the first node, and a second electrode of the second transistor is coupled with a second node; A control electrode of the third transistor is coupled with the first node, a first electrode of the third transistor is coupled with the second node, and a second electrode of the third transistor is coupled with a third node; A control electrode of the fourth transistor is coupled with an enable signal terminal, a first electrode of the fourth transistor is coupled with a high voltage terminal, and a second electrode of the fourth transistor is coupled with the third node; A control electrode of the fifth transistor is coupled with the gate driving voltage terminal, a first electrode of the fifth transistor is coupled with a data signal terminal, and a second electrode of the fifth transistor is coupled with the third node; A control electrode of the sixth transistor is coupled with the enable signal terminal, a first electrode of the sixth transistor is coupled with the second node, and a second electrode of the sixth transistor is coupled with a fourth node; A control electrode of the seventh transistor is coupled with the scanning signal terminal, a first electrode of the seventh transistor is coupled with the fourth node, and a second electrode of the seventh transistor T7 is coupled with a fifth node; A control electrode and a first electrode of the eighth transistor are coupled with the reference voltage terminal, and a second electrode of the eighth transistor is coupled with the fifth node; A first plate of the first capacitor is coupled with a high voltage terminal, and a second plate of the first capacitor is coupled with the first node N1; and A first end of the first sub-light emitting element is coupled with the fourth node, and a second end of the first sub-light emitting element is coupled with a low voltage terminal, The fifth node is coupled with a reading signal line. The first direction extends along a width direction of the first sub-light emitting element, and a normal projection of the light blocking element on the substrate overlaps with a normal projection of the first sub-light emitting element on the substrate in the first direction. A size of the first opening along the first direction is smaller than a size of the light sensing element.

19. A drive circuit for a pixel, wherein, The pixel is located on a substrate, and the pixel comprises: a light emitting element located on the substrate, wherein the light emitting element comprises a first sub-light emitting element, the first sub-light emitting element is multiplexed as a light sensing element and is configured to sense reflected light reflected from an object contacting or adjacent to the light sensing element, and generate a sensing signal according to the sensed reflected light; and a light blocking element, a normal projection of the light blocking element on the substrate is adjacent to and surrounds a normal projection of the light sensing element on the substrate, so as to block light other than the reflected light from entering the light sensing element, the driving circuit comprises a first transistor to a sixth transistor, a first capacitor and a first sub-light emitting element: The control electrode of the first transistor is coupled with a scan signal end, the first electrode of the first transistor is coupled with a first node, and the second electrode of the first transistor is coupled with a second node, wherein the second node is coupled with a read signal line; The control electrode of the second transistor is coupled with a third node, the first electrode of the second transistor is coupled with a high-voltage end, and the second electrode of the second transistor is coupled with the first node; The control electrode of the third transistor is coupled with a gate driving voltage end, the first electrode of the third transistor is coupled with a data signal end, and the second electrode of the third transistor is coupled with the third node N3; The control electrode of the fourth transistor is coupled with a previous-stage gate driving signal end, the first electrode of the fourth transistor is coupled with the first node, and the second electrode of the fourth transistor is coupled with the second node; The control electrode of the fifth transistor is coupled with the previous-stage gate driving signal end, the first electrode of the fifth transistor is coupled with a first low-voltage end, and the second electrode of the fifth transistor is coupled with the first node; The control electrode of the sixth transistor is coupled with the previous-stage gate driving signal end, the first electrode of the sixth transistor is coupled with the third node, and the second electrode of the sixth transistor is coupled with a second low-voltage end; The first plate of the first capacitor is coupled with a high-voltage end, and the second plate of the first capacitor is coupled with the third node; and One end of the first sub-light emitting element is coupled with the first node, and the second end of the first sub-light emitting element is coupled with the second low-voltage end.

20. A display device comprising the display substrate according to any one of claims 1 to 18.

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