Display substrate and manufacturing method therefor, display panel, and display device

Abstract

Provided are a display substrate and a manufacturing method therefor, a display panel, and a display device. The display substrate comprises: a base substrate, comprising a display area and a peripheral area, the peripheral area at least partially surrounding the display area; and a plurality of pixel units located in the display area of the base substrate, the plurality of pixel units being arranged in the display area in an array in a first direction and a second direction, at least one pixel unit comprising a reflective bonding structure and an LED light-emitting unit, and the first direction intersecting with the second direction, wherein the reflective bonding structure comprises: a first electrode, a first reflecting electrode and a first bonding portion which are sequentially arranged on the base substrate; and the LED light-emitting unit comprises: a second bonding portion, an LED epitaxial layer and a second electrode which are sequentially arranged on the side of the first bonding portion distant from the base substrate, wherein the orthographic projection of the second bonding portion on the base substrate is located in the orthographic projection of the first bonding portion on the base substrate; and the first bonding portion and the second bonding portion comprise a same material.

Description

Display substrate and manufacturing method thereof, display panel and display device Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a display substrate and a preparation method thereof, a display panel, and a display device. Background Art

[0002] With the explosion of the metaverse, augmented reality (AR) display technology is experiencing rapid development. AR display systems primarily consist of microdisplay units for displaying content, image synthesis, and optical systems for viewing the eye. Currently, microdisplay units used for AR displays include micro-LED (micro-light-emitting diode) displays.

[0003] However, Micro-LEDs face numerous challenges that hinder their development, including uniformity of the LED epitaxial layer, miniaturization, degradation of light efficiency during the miniaturization process, and technical bottlenecks such as high-precision bonding. Achieving high brightness and high resolution during LED miniaturization is a key research topic for researchers.

[0004] The above information disclosed in this section is only for understanding the background of the inventive concept of the present disclosure and therefore the above information may contain information that does not constitute prior art.

[0005] Summary of the Invention

[0006] In one aspect, a display substrate is provided, wherein the display substrate comprises: a base substrate, the base substrate comprising a display area and a peripheral area, the peripheral area at least partially surrounding the display area; and a plurality of pixel units located in the display area of ​​the base substrate, the plurality of pixel units being arrayed in the display area along a first direction and a second direction, at least one of the pixel units comprising a reflective bonding structure and an LED light-emitting unit, wherein the first direction and the second direction intersect, wherein the reflective bonding structure comprises: a first electrode disposed on the base substrate; a first reflective electrode disposed on a side of the first electrode away from the base substrate; and a first bonding portion disposed on a side of the first reflective electrode away from the base substrate; the LED light-emitting unit comprises: a second bonding portion disposed on a side of the first bonding portion away from the base substrate; an LED epitaxial layer disposed on a side of the second bonding portion away from the base substrate; and a second electrode disposed on a side of the LED epitaxial layer away from the base substrate, wherein the orthographic projection of the second bonding portion on the base substrate is located within the orthographic projection of the first bonding portion on the base substrate; and the first bonding portion and the second bonding portion comprise the same material.

[0007] According to some exemplary embodiments, the first bonding portion and the second bonding portion include a same material selected from ITO or IZO.

[0008] According to some exemplary embodiments, the first bonding portion includes a first slope angle, and the first slope angle ranges from 70° to 85°; and / or the second bonding portion includes a second slope angle, and the second slope angle ranges from 70° to 85°.

[0009] According to some exemplary embodiments, the material of the first electrode is one of ITO and IZO; and / or the material of the first reflective electrode is silver.

[0010] According to some exemplary embodiments, the display substrate further includes an isolation portion located between adjacent pixel units, the isolation portion covering at least a portion of the surface of the LED epitaxial layer away from the base substrate, the side wall of the reflective bonding structure and the side wall of the LED light-emitting unit.

[0011] According to some exemplary embodiments, the isolation portion has a first thickness in a third direction, wherein the third direction is perpendicular to the first direction and the second direction; the reflective bonding structure has a second thickness in the third direction; the second bonding portion has a third thickness in the third direction; and the LED epitaxial layer has a fourth thickness in the third direction, wherein the first thickness is greater than the sum of the second thickness, the third thickness and the fourth thickness.

[0012] According to some exemplary embodiments, the LED epitaxial layer includes: a second semiconductor layer arranged on a side of the second bonding portion away from the substrate substrate; a quantum well layer arranged on a side of the second semiconductor layer away from the substrate substrate; and a first semiconductor layer arranged on a side of the quantum well layer away from the substrate substrate; and the isolation portion includes an opening, the opening exposing at least a portion of the surface of the first semiconductor layer away from the substrate substrate.

[0013] According to some exemplary embodiments, the second electrode includes a main body portion and a second conductive connecting portion, the orthographic projection of the second conductive connecting portion on the base substrate coincides with the orthographic projection of the isolation portion on the base substrate, and the second electrodes of two adjacent pixel units are electrically connected through the second conductive connecting portion, wherein the main body portion has a fifth thickness in the third direction, the second conductive connecting portion has a sixth thickness in the third direction, and the fifth thickness is greater than the sixth thickness.

[0014] According to some exemplary embodiments, the display substrate further includes a metal conductive layer arranged on a side of the second electrode away from the base substrate, wherein the orthographic projection of the metal conductive layer on the base substrate is located within the orthographic projection of the second conductive connection portion on the base substrate; and the metal conductive layer includes a plurality of first conductive sub-portions arranged along a first direction and a plurality of second conductive sub-portions arranged along a second direction, and the plurality of first conductive sub-portions and the plurality of second conductive sub-portions are electrically connected to each other.

[0015] According to some exemplary embodiments, the metal conductive layer includes a first metal conductive sublayer arranged on the side of the second electrode away from the base substrate; a second metal conductive sublayer arranged on the side of the first metal conductive sublayer away from the base substrate; and a third metal conductive sublayer arranged on the side of the second metal conductive sublayer away from the base substrate, wherein the orthographic projection of the second metal conductive sublayer on the base substrate is located within the orthographic projection of the first metal conductive sublayer on the base substrate; and the orthographic projection of the third metal conductive sublayer on the base substrate is located within the orthographic projection of the second metal conductive sublayer on the base substrate.

[0016] According to some exemplary embodiments, the display substrate further comprises a prism portion disposed on a side of the second electrode away from the base substrate, wherein an orthographic projection of the prism portion on the base substrate at least partially overlaps with an orthographic projection of the LED epitaxial layer on the base substrate.

[0017] According to some exemplary embodiments, the display substrate further includes a first conductive transition portion and a second conductive transition portion located in the peripheral area, the first conductive transition portion and the second conductive transition portion being electrically connected, wherein the first conductive transition portion includes a first conductive transfer sub-portion, a second conductive transfer sub-portion, a third conductive transfer sub-portion and a fourth conductive transfer sub-portion, wherein the first conductive transfer sub-portion and the first electrode are located on the same layer; the second conductive transfer sub-portion and the first reflective electrode are located on the same layer; the third conductive transfer sub-portion and the first bonding portion are located on the same layer; and the fourth conductive transfer sub-portion and the second bonding portion are located on the same layer; and the second conductive transfer sub-portion includes a fifth conductive transfer sub-portion and a sixth conductive transfer sub-portion, wherein the fifth conductive transfer sub-portion and the second electrode are located on the same layer; and the sixth conductive transfer sub-portion and the metal conductive layer are located on the same layer.

[0018] According to some exemplary embodiments, the display substrate further includes an inorganic encapsulation layer disposed between the LED light emitting unit and the prism portion.

[0019] According to some exemplary embodiments, the inorganic encapsulation layer includes n inorganic encapsulation sublayers arranged alternately, wherein two adjacent inorganic encapsulation sublayers among the n inorganic encapsulation sublayers have different refractive indices, and n is a positive integer greater than or equal to 3.

[0020] According to some exemplary embodiments, the refractive index of the material of the even-numbered inorganic encapsulation sub-layers among the n inorganic encapsulation sub-layers is greater than or equal to 1.85.

[0021] According to some exemplary embodiments, the prism portion includes a top surface away from the base substrate, and the top surface is a convex arc surface.

[0022] According to some exemplary embodiments, the curvature radius of the convex arc surface is greater than or equal to 2 μm.

[0023] According to some exemplary embodiments, the display substrate further includes: a third via hole located between the inorganic packaging layers of adjacent LED light-emitting units; and a reflective layer located in the third via hole, wherein the reflective layer is used to reflect at least a portion of the light emitted from the side by the LED light-emitting unit.

[0024] According to some exemplary embodiments, the reflective layer includes m inorganic reflective sublayers arranged alternately, and the difference in refractive index between two adjacent inorganic reflective sublayers among the m inorganic reflective sublayers is greater than or equal to 0.4, where m is a positive integer greater than or equal to 2.

[0025] According to some exemplary embodiments, the reflective layer includes a metal reflective layer or a black glue reflective layer.

[0026] In another aspect, a display panel is provided, wherein the display panel includes the display substrate as described in any one of the above descriptions.

[0027] In yet another aspect, a display device is provided, wherein the display device includes the display substrate as described in any one of the foregoing descriptions or the display panel as described in the foregoing descriptions.

[0028] In yet another aspect, a method for preparing a display substrate is provided, wherein the method comprises: sequentially depositing a first electrode material layer, a first reflective electrode material layer, and a first bonding material layer on a base substrate; performing a patterning process on the first electrode material layer, the first reflective electrode material layer, and the first bonding material layer to form an array-arranged reflective bonding structure, wherein the reflective bonding structure comprises a first electrode located in the first electrode material layer, a first reflective electrode located in the first reflective electrode material layer, and a first bonding portion located in the first bonding material layer; epitaxially growing a semiconductor buffer material layer, a first semiconductor material layer, a quantum well material layer, and a second semiconductor material layer on a wafer to form an LED epitaxial layer; and depositing a second bonding material layer on the second semiconductor material layer. material layer; performing a bonding process on the entire second bonding material layer and the reflective bonding structure arranged in an array; after completing the bonding process, peeling off the wafer, removing the semiconductor buffer material layer, and thinning the first semiconductor material layer to form a thinned LED epitaxial layer; performing a composition process on the thinned LED epitaxial layer and the second bonding material layer to form a first via hole, and forming a plurality of LED light-emitting portions arranged in an array corresponding to the reflective bonding structure; forming an insulating layer on a side of the LED epitaxial layer away from the base substrate, and performing a composition process on the insulating layer to form a second via hole exposing the LED epitaxial layer, and forming an isolation portion between adjacent LED light-emitting units; and forming a second electrode layer on a side of the insulating layer away from the base substrate.

[0029] According to some exemplary embodiments, the method further includes: alternately forming a first inorganic packaging sublayer and a second inorganic packaging sublayer on a side of the LED light-emitting unit away from the base substrate to form an inorganic packaging layer comprising n inorganic packaging sublayers, wherein n is a positive integer greater than or equal to 3; forming a first prism layer on a side of the inorganic packaging layer away from the base substrate; forming a photoresist layer on a side of the first prism layer away from the base substrate, and performing a patterning process on the photoresist layer to form a photoresist retention portion corresponding to the LED light-emitting unit; performing a thermal reflow process on the photoresist retention portion to form a photoresist prism portion; and simultaneously etching the photoresist prism portion and the first prism layer until the photoresist prism portion is removed and an array of prism portions corresponding to the LED light-emitting unit is formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Features and advantages of the present disclosure will become more apparent by describing in detail exemplary embodiments of the present disclosure with reference to the accompanying drawings.

[0031] FIG1 is a schematic plan view of a display substrate according to some exemplary embodiments of the present disclosure;

[0032] FIG2 is a schematic cross-sectional view of a display substrate taken along line AA′ in FIG1 according to some exemplary embodiments of the present disclosure;

[0033] FIG3 is a partial enlarged schematic diagram of a display substrate at a dotted line area S in FIG2 according to some exemplary embodiments of the present disclosure;

[0034] FIG4 is a schematic cross-sectional view of a display substrate according to some other exemplary embodiments of the present disclosure taken along line AA′ in FIG1 ;

[0035] FIG5 is a partial plan view of the metal conductive layer in FIG4 ;

[0036] FIG6 is a schematic cross-sectional view of a display substrate taken along line AA′ in FIG1 according to some other exemplary embodiments of the present disclosure;

[0037] FIG7 is a schematic cross-sectional view of a display substrate taken along line BB′ in FIG1 according to some exemplary embodiments of the present disclosure;

[0038] FIG8 is a schematic cross-sectional view of a display substrate taken along line CC′ in FIG1 according to some exemplary embodiments of the present disclosure;

[0039] FIG9A is a schematic structural diagram of an inorganic encapsulation layer in a display substrate according to some exemplary embodiments of the present disclosure;

[0040] FIG9B is a schematic structural diagram of an inorganic encapsulation layer in a display substrate according to other exemplary embodiments of the present disclosure;

[0041] FIG10 is a diagram illustrating the effect of a gas ratio on a refractive index of an inorganic encapsulation layer according to some exemplary embodiments of the present disclosure;

[0042] FIG11 is a schematic diagram showing a comparison of light output intensities of display substrates with different prism diameters at different viewing angles according to some exemplary embodiments of the present disclosure;

[0043] FIG12 is a schematic diagram of crosstalk between adjacent pixels of a display substrate at different viewing angles according to some exemplary embodiments of the present disclosure; and

[0044] FIG13 is a schematic structural diagram of a reflective layer of a display substrate according to some exemplary embodiments of the present disclosure;

[0045] FIG14A is a schematic diagram illustrating the structure of a reflective layer of a display substrate according to some other exemplary embodiments of the present disclosure; FIG14B is a schematic diagram illustrating photon density distribution of a display substrate without a reflective layer according to some exemplary embodiments of the present disclosure; FIG14C is a schematic diagram illustrating photon density distribution of a display substrate provided with the reflective layer shown in FIG14A;

[0046] FIG15 is a schematic structural diagram of a display panel according to some exemplary embodiments of the present disclosure;

[0047] FIG16 is a schematic structural diagram of a display device according to some exemplary embodiments of the present disclosure;

[0048] FIG17 is a flow chart of a method for preparing a display substrate according to some exemplary embodiments of the present disclosure; FIG18 to FIG26 are schematic diagrams of partial structures of the display substrate at different stages of the preparation process of FIG17 ; and

[0049] FIG27 is a flow chart of forming an inorganic encapsulation layer and a prism portion according to some exemplary embodiments of the present disclosure; and FIG28 to FIG32 are schematic diagrams of partial structures of a display substrate at different stages in the preparation process of FIG27 .

[0050] It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present invention, the sizes of layers, structures or regions may be enlarged or reduced, that is, these drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0051] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0052] It should be noted that in the drawings, the sizes and relative sizes of elements may be exaggerated for clarity and / or descriptive purposes. Thus, the sizes and relative sizes of the individual elements are not necessarily limited to those shown in the drawings. In the specification and drawings, the same or similar reference numerals indicate the same or similar parts.

[0053] Unless otherwise defined, technical or scientific terms used in this disclosure should have the ordinary meanings understood by those of ordinary skill in the art. The terms "first," "second," and similar terms used in this disclosure do not denote any order, quantity, or importance, but are simply used to distinguish different components. The terms "include," "comprising," and similar words mean that the element or object preceding the word encompasses the elements or objects listed after the word, and their equivalents, without excluding other elements or objects.

[0054] Unless otherwise specified, directional terms such as "upper," "lower," "left," "right," "inner," and "outer" are used herein to indicate positions or relationships based on the figures shown. These terms are intended solely to facilitate the description of the present disclosure and are not intended to indicate or imply that the devices, components, or parts referred to must have, be constructed, or operate in a specific orientation. It should be understood that when the absolute positions of the objects being described change, the relative positions they represent may also change accordingly. Therefore, these directional terms should not be construed as limiting the present disclosure.

[0055] It should be noted that, in this article, the term "the same layer" refers to a layer structure formed by using the same film-forming process to form a film layer used to form a specific pattern, and then patterning the film layer using the same mask through a single patterning process. Depending on the specific pattern, a single patterning process may include multiple exposure, development, or etching processes, and the specific pattern in the resulting layer structure may be continuous or discontinuous. In other words, multiple elements, components, structures, and / or parts located in the "same layer" are composed of the same material and are formed through the same patterning process. Typically, multiple elements, components, structures, and / or parts located in the "same layer" have approximately the same thickness.

[0056] Those skilled in the art should understand that, in this article, unless otherwise specified, the expression "height" or "thickness" refers to the dimension of the surface of each film layer arranged perpendicular to the display substrate, that is, the dimension along the light emitting direction of the display substrate, or the dimension along the normal direction of the display device.

[0057] In this document, the directional expressions "first direction" and "second direction" are used to describe different directions along a pixel unit, such as the longitudinal and transverse directions of a pixel unit, or the row and column directions of a sub-pixel arrangement. It should be understood that such expressions are merely exemplary descriptions and are not intended to limit the present disclosure.

[0058] In this article, inorganic light-emitting diodes refer to light-emitting elements made of inorganic materials, where LED represents an inorganic light-emitting element that is different from OLED. Specifically, inorganic light-emitting elements can include sub-millimeter light-emitting diodes (Mini Light Emitting Diode, abbreviated as Mini LED in English) and micro light-emitting diodes (Micro LED in English). Among them, micro light-emitting diodes (i.e. Micro LEDs) refer to ultra-small light-emitting diodes with a grain size of less than 100 microns, and sub-millimeter light-emitting diodes (i.e. Mini LEDs) refer to small light-emitting diodes with a grain size between Micro LEDs and traditional LEDs. For example, the grain size of Mini LEDs can be between 50 and 400 microns.

[0059] LEDs, due to their high refresh rate, high brightness, active light-emitting mode, and miniaturization, can be used to manufacture mini LED and Micro LED displays. Micro LEDs, with their excellent brightness, high luminous efficiency, low energy consumption, high response speed, high contrast, ultra-high resolution, and color saturation, are considered an ideal display technology. Micro LEDs possess most of the advantages of LEDs, and are also small, easy to disassemble, and highly flexible, making them the most promising optical engines for AR products. Although Micro-LEDs possess incomparable advantages, numerous challenges hinder their development, primarily including epitaxial layer uniformity, miniaturization processes, luminous efficiency degradation during miniaturization, efficiency degradation at low currents, high-precision bonding technology, ultra-high-resolution Micro-LED drive technology, colorization, and high costs. Achieving high-precision bonding between high-density LED chips and the drive circuitry in the substrate during LED miniaturization is a pressing issue in the development of high-resolution Micro-LED displays.

[0060] In an embodiment of the present disclosure, a display substrate is provided, wherein the display substrate comprises: a base substrate, the base substrate comprising a display area and a peripheral area, the peripheral area at least partially surrounding the display area; and a plurality of pixel units located in the display area of ​​the base substrate, the plurality of pixel units being arrayed in the display area along a first direction and a second direction, at least one of the pixel units comprising a reflective bonding structure and an LED light-emitting unit, wherein the first direction and the second direction intersect, wherein the reflective bonding structure comprises: a first electrode disposed on the base substrate; a first reflective electrode disposed on a side of the first electrode away from the base substrate; and a first bonding portion disposed on a side of the first reflective electrode away from the base substrate; the LED light-emitting unit comprises: a second bonding portion disposed on a side of the first bonding portion away from the base substrate; an LED epitaxial layer disposed on a side of the second bonding portion away from the base substrate; and a second electrode disposed on a side of the LED epitaxial layer away from the base substrate, wherein an orthographic projection of the second bonding portion on the base substrate is located within an orthographic projection of the first bonding portion on the base substrate; and the first bonding portion and the second bonding portion comprise the same material. By forming an array of first bonding sections on the substrate and forming a second bonding material layer on the LED epitaxial layer, made entirely of the same material as the first bonding sections, the LED epitaxial layer is bonded to the substrate without requiring alignment, improving bonding efficiency. Furthermore, after bonding, a patterning process is used to create a micro-array design of the LED epitaxial layer and the second bonding material layer, ensuring that the orthographic projection of the second bonding section on the substrate lies within the orthographic projection of the first bonding section on the substrate, forming an array of LED light-emitting units and achieving a high-resolution display design.

[0061] FIG. 1 is a schematic plan view of a display substrate according to some exemplary embodiments of the present disclosure.

[0062] Referring to Figure 1 , a display substrate 100 includes a base substrate 1 including a display area AA and a peripheral area EA, wherein the peripheral area EA at least partially surrounds the display area AA; a plurality of pixel units PX located within the display area AA of the base substrate 1, wherein the pixel units PX are arranged in an array along a first direction D1 and a second direction D2 within the display area AA, wherein the first direction D1 and the second direction D2 intersect. The display substrate 100 also includes a binding area 400 located within the peripheral area EA, which can be used to electrically connect the display substrate to an external driver chip.

[0063] It should be noted that although the drawings schematically illustrate circular pixel units PX in the embodiments of the present disclosure, in other embodiments, the pixel openings may also be various shapes, such as rectangular, elliptical, square, or triangular. Furthermore, the light-emitting units of different colors corresponding to different pixel units may be arranged in various manners known in the art, and the embodiments of the present disclosure do not impose any particular limitation thereto.

[0064] FIG. 2 is a schematic cross-sectional view of a display substrate taken along line AA′ in FIG. 1 according to some exemplary embodiments of the present disclosure.

[0065] For example, referring to Figure 2 , at least one pixel unit PX includes a reflective bonding structure 20 and an LED light-emitting unit 30. The LED light-emitting unit 30 can emit one of red, green, and blue light. The reflective bonding structure 20 includes: a first electrode 21 disposed on a substrate 1; a first reflective electrode 22 disposed on a side of the first electrode 21 away from the substrate 1; and a first bonding portion 23 disposed on a side of the first reflective electrode 22 away from the substrate 1. The LED light-emitting unit 30 includes: a second bonding portion 31 disposed on a side of the first bonding portion 23 away from the substrate 1; an LED epitaxial layer 32 disposed on a side of the second bonding portion 31 away from the substrate; and a second electrode 33 disposed on a side of the LED epitaxial layer 32 away from the substrate.

[0066] In this embodiment, the second bonding portion 31 and the first bonding portion 23 comprise the same material, which is beneficial to improving the bonding strength between the second bonding portion 31 and the first bonding portion 23 and ensuring that the LED light emitting unit 30 is tightly combined with the substrate 1 .

[0067] For example, the thickness of the first bonding portion 23 is 10 to 500 nm, and the thickness of the second bonding portion 31 is 50 to 500 nm. The surface roughness of the first bonding portion 23 and the second bonding portion 31 is less than 1 nm. For example, the surface roughness of the first bonding portion 23 and the second bonding portion 31 is less than 0.5 nm. By controlling the roughness, the bonding strength between the first bonding portion and the second bonding portion can be increased, thereby improving the reliability of the display substrate.

[0068] In some embodiments of the present disclosure, the base substrate 1 further includes a driver circuit (not shown) for driving the pixel unit. The first and second bonding portions not only physically bond the LED light-emitting unit to the base substrate, but also electrically connect the LED light-emitting unit to the driver circuit in the base substrate by designing the first and second bonding portions to be conductive materials, thereby enabling drive control of the LED light-emitting unit. For example, the first and second bonding portions 23 and 31 may comprise the same material selected from ITO or IZO.

[0069] In some embodiments of the present disclosure, the first electrode 21, the first reflective electrode 22, and the first bonding portion 23 included in the reflective bonding structure 20 are electrically connected to each other. For example, the material of the first electrode 21 can be one of ITO or IZO, and the thickness of the first electrode 21 is 10 to 500 nm; and / or the material of the first reflective electrode 22 can be silver, and the thickness of the first reflective electrode 22 is 50 to 500 nm. By designing a first reflective electrode between the LED light-emitting unit and the substrate, it is possible to ensure that most of the light emitted by the LED light-emitting unit is emitted in a direction away from the substrate, thereby improving the light extraction efficiency of the display substrate and achieving high-brightness display.

[0070] For example, in some embodiments of the present disclosure, referring again to FIG. 2 , the display substrate 100 further includes an isolation portion 40 located between adjacent pixel units PX. The isolation portion 40 covers at least a portion of the surface 320 of the LED epitaxial layer 32 facing away from the base substrate, the sidewalls 201 of the reflective bonding structure 20, and the sidewalls 301 of the LED light-emitting unit. The isolation portion 40 has a first thickness h1 in a third direction D3, wherein the third direction D3 is perpendicular to the first direction D1 and the second direction D2. The reflective bonding structure 20 has a second thickness h2 in the third direction D3. The second bonding portion 31 has a third thickness h3 in the third direction D3. The LED epitaxial layer 32 has a fourth thickness h4 in the third direction D3. In embodiments of the present disclosure, the first thickness h1 is greater than the sum of the second thickness h2, the third thickness h3, and the fourth thickness h4. By designing an isolation portion between adjacent pixel units PX, leakage between adjacent pixel units PX can be reduced, thereby improving the display quality of the display substrate.

[0071] Exemplarily, the material of the isolation portion may include SiO2, SiN or SiON, or a stack of any two or three of SiO2, SiN and SiON, or an organic insulating layer such as spin on glass (SOG), benzocyclobutene BCB, etc.

[0072] FIG. 3 is a partially enlarged schematic diagram of a display substrate at a dotted area S in FIG. 2 according to some exemplary embodiments of the present disclosure.

[0073] Illustratively, in some embodiments of the present disclosure, the first bonding portion 23 can form a regular trapezoidal structure through a patterning process, wherein the first bonding portion 23 includes a first slope angle 231, and the range of the first slope angle 231 is between 70° and 85°; and / or, the second bonding portion 31 can form a regular trapezoidal structure through a patterning process, wherein the second bonding portion 31 includes a second slope angle 311, and the range of the second slope angle 311 is between 70° and 85°. The first slope angle 231 can be greater than the second slope angle 311, for example, the first slope angle 231 is 85° and the second slope angle 311 is 70°; or, the first slope angle 231 can be equal to the second slope angle 311, for example, the first slope angle 231 is 80° and the second slope angle 311 is 80°; or, the first slope angle 231 can be less than the second slope angle 311, for example, the first slope angle 231 is 70° and the second slope angle 311 is 85°.

[0074] 3 , the orthographic projection of the second bonding portion 31 on the substrate is within the orthographic projection of the first bonding portion 23. The orthographic projection of the LED epitaxial layer 32 on the substrate is within the orthographic projection of the second bonding portion 31 on the substrate.

[0075] By designing the orthographic projection of the second bonding portion 31 on the substrate to lie within the orthographic projection of the first bonding portion 23 on the substrate, the bonding strength between the second bonding portion 31 and the first bonding portion 23 can be improved. Furthermore, by designing the first bonding portion 23 and the second bonding portion 31 to have a large slope angle, a good bond between the first bonding portion 23 and the second bonding portion 31 can be achieved while minimizing the space occupied by the non-luminescent portion, thereby increasing the duty cycle of the luminescent area and facilitating high-resolution display.

[0076] For example, in some embodiments of the present disclosure, with continued reference to FIG. 3 , the LED epitaxial layer 32 includes: a second semiconductor layer 321 disposed on a side of the second bonding portion 31 away from the substrate 1; a quantum well layer 322 disposed on a side of the second semiconductor layer 321 away from the substrate 1; and a first semiconductor layer 323 disposed on a side of the quantum well layer 322 away from the substrate. The LED epitaxial layer 32 can generate one of blue, red, or green light under an applied electric field. For example, the first semiconductor layer 323 can include n-GaN material, the quantum well layer 322 can include multiple pairs of quantum wells, for example, the quantum well layer 322 can include 1 to 25 pairs of quantum wells, and the second semiconductor layer 321 can include p-GaN material, thereby enabling the LED epitaxial layer 32 to generate blue light when an electric field is applied.

[0077] Exemplarily, the isolation portion 40 includes an opening VH, which exposes at least a portion of the surface 320 of the first semiconductor layer 323 away from the substrate. Continuing with FIG3 , the opening VH has a first width d1 in the first direction, and the first semiconductor layer 323 has a second width d2 in the first direction away from the substrate surface 320. The first width d1 is smaller than the second width d2. For example, the second width d2 differs from the first width d1 by 0.1 μm or more. This ensures the isolation effect of the isolation portion while maximizing the utilization of the light-emitting area, reduces leakage between pixel units, and improves the display quality of the display substrate.

[0078] For example, in some embodiments of the present disclosure, in combination with Figures 2 and 3, the second electrode 33 includes a main body portion 331 and a second conductive connection portion 332, the orthographic projection of the second conductive connection portion 332 on the base substrate 1 coincides with the orthographic projection of the isolation portion 40 on the base substrate, and the second electrodes 33 of two adjacent pixel units PX are electrically connected through the second conductive connection portion 332, wherein the main body portion 331 has a fifth thickness h5 in the third direction D3, and the second conductive connection portion 332 has a sixth thickness h6 in the third direction D3, and the fifth thickness h5 is greater than the sixth thickness h6.

[0079] By designing the electrical connection between the second electrodes of adjacent pixel units, a common cathode design of multiple pixel units can be achieved, which can save wiring space and is conducive to achieving a high-resolution display design.

[0080] 4 is a schematic cross-sectional view of a display substrate according to some other exemplary embodiments of the present disclosure taken along line AA′ in FIG. 1 ; and FIG. 5 is a schematic partial plan view of a metal conductive layer in FIG. 4 .

[0081] Exemplarily, in some embodiments of the present disclosure, in combination with Figures 4 and 5, the display substrate 100 also includes a metal conductive layer 50 arranged on the side of the second electrode 33 away from the base substrate 1, wherein the orthographic projection of the metal conductive layer 50 on the base substrate 1 is located within the orthographic projection of the second conductive connection portion 332 on the base substrate 1; and the metal conductive layer 50 includes a plurality of first conductive sub-portions 510 extending along the first direction D1 and a plurality of second conductive sub-portions 520 extending along the second direction D2, and the plurality of first conductive sub-portions 510 and the plurality of second conductive sub-portions 520 are electrically connected to each other, thereby forming a mesh metal auxiliary electrode.

[0082] By providing a metal conductive layer 50 above the second electrode 33 and electrically connecting the second electrode 33 to the metal conductive layer 50, the voltage drop of the control signal during transmission can be reduced, thereby improving the uniformity of light emission of each pixel unit and enhancing the display effect of the display substrate. The orthographic projection of the metal conductive layer 50 on the base substrate 1 does not overlap with the orthographic projection of the LED light-emitting unit 30 on the base substrate 1, thereby ensuring that the light-transmitting area of ​​the pixel unit is as large as possible, which is conducive to achieving high-resolution display.

[0083] For example, in some embodiments of the present disclosure, with continued reference to FIG. 4 , the metal conductive layer 50 may include multiple metal conductive sublayers in a stacked design. For example, the metal conductive layer 50 includes a first metal conductive sublayer 501 disposed on a side of the second electrode 33 away from the base substrate 1; a second metal conductive sublayer 502 disposed on a side of the first metal conductive sublayer 501 away from the base substrate 1; and a third metal conductive sublayer 503 disposed on a side of the second metal conductive sublayer 502 away from the base substrate, wherein the orthographic projection of the second metal conductive sublayer 502 on the base substrate 1 is located within the orthographic projection of the first metal conductive sublayer 501 on the base substrate 1; and the orthographic projection of the third metal conductive layer 503 on the base substrate 1 is located within the orthographic projection of the second metal conductive sublayer 502 on the base substrate 1. For example, the material of the first metal conductive sublayer 501 is Ti, the material of the second metal conductive sublayer 502 is Al, and the material of the third metal conductive sublayer 503 is Ti. The first metal conductive sublayer 501, the second metal conductive sublayer 502, and the third metal conductive sublayer 503 can all be formed using a sputtering coating process, which has high production efficiency. Furthermore, the first metal conductive sublayer 501, the second metal conductive sublayer 502, and the third metal conductive sublayer 503 can be patterned using a dry etching process, which has high patterning accuracy and is conducive to achieving high-resolution display.

[0084] For example, the metal conductive layer 50 can also reflect light, and by optimizing the thickness and angle of the second metal conductive sub-layer 502 , the light extraction efficiency of the display substrate can be improved.

[0085] FIG. 6 is a schematic cross-sectional view of a display substrate according to some other exemplary embodiments of the present disclosure, taken along line AA′ in FIG. 1 .

[0086] For example, in some embodiments of the present disclosure, the display substrate 100 further includes a prism portion 60 disposed on a side of the second electrode 33 away from the base substrate 1 , wherein the orthographic projection of the prism portion 60 on the base substrate 1 at least partially overlaps with the orthographic projection of the LED epitaxial layer 32 on the base substrate 1 .

[0087] Exemplarily, the prism portion 60 may include an organic material, such as photoresist, or an inorganic material, such as one or more combinations of SiO 2 , SiON, or SiN.

[0088] By providing a prism portion above the LED epitaxial layer, the probability of total reflection on the light-emitting side can be reduced, the light-emitting efficiency of the display substrate can be improved, and high-brightness display can be achieved.

[0089] FIG. 7 is a schematic cross-sectional view of a display substrate taken along line BB′ in FIG. 1 according to some exemplary embodiments of the present disclosure.

[0090] For example, in some embodiments of the present disclosure, the display substrate 100 further includes a first conductive transition portion 70 and a second conductive transition portion 80 located in the peripheral area EA. The first conductive transition portion 70 and the second conductive transition portion 80 are electrically connected, wherein the first conductive transition portion 70 includes a first conductive transition sub-portion 701, a second conductive transition sub-portion 702, a third conductive transition sub-portion 703, and a fourth conductive transition sub-portion 704. For example, the first conductive transition sub-portion 701 is located on the same layer as the first electrode 21; the second conductive transition sub-portion 702 is located on the same layer as the first reflective electrode 22; the third conductive transition sub-portion 703 is located on the same layer as the first bonding portion 23; and the fourth conductive transition sub-portion 704 is located on the same layer as the second bonding portion 31. The first conductive transfer sub-section 701, the second conductive transfer sub-section 702 and the third conductive transfer sub-section 703 can be formed in the same process step with the reflective bonding structure 20, and the fourth conductive transfer sub-section 704 can be formed in the same process step with the second bonding section 31, thereby saving process steps and improving production efficiency.

[0091] Exemplarily, the second conductive transition portion 80 includes a fifth conductive transition sub-portion 801 and a sixth conductive transition sub-portion 802. For example, the fifth conductive transition sub-portion 801 is located on the same layer as the second electrode 33; the sixth conductive transition sub-portion 802 is located on the same layer as the metal conductive layer 50. The second conductive transition sub-portion 80 is electrically connected to the first conductive transition portion 70, thereby achieving an electrical connection between the common cathode and the drive circuit in the substrate. This reduces wiring and saves wiring space while ensuring driving effects.

[0092] To improve the stability of the light-emitting unit and extend the service life of the display substrate, the display substrate may also include an encapsulation layer disposed above the LED light-emitting unit. Conventional LED light-emitting unit encapsulation often employs an inorganic layer-organic layer-inorganic layer stacked structure. However, in order to ensure a good encapsulation effect, the organic layer in the inorganic layer-organic layer-inorganic layer stacked structure must be designed to be thicker, thereby increasing the thickness of the overall display substrate and hindering the realization of a thinner and lighter display substrate.

[0093] After research, the inventors found that compared with the traditional inorganic layer-organic layer-inorganic layer stacked structure, the use of a pure inorganic stacked packaging structure can provide good protection for the LED light-emitting unit while reducing the thickness of the packaging layer, which is beneficial to the overall thinning of the display substrate and the realization of a lighter and thinner display substrate.

[0094] Figure 8 is a schematic cross-sectional view of a display substrate according to some exemplary embodiments of the present disclosure taken along line CC' in Figure 1; Figure 9A is a schematic structural view of an inorganic encapsulation layer in a display substrate according to some exemplary embodiments of the present disclosure; Figure 9B is a schematic structural view of an inorganic encapsulation layer in a display substrate according to other exemplary embodiments of the present disclosure; and Figure 10 is a schematic diagram of the relationship between the influence of the gas ratio on the refractive index of the inorganic encapsulation layer in some exemplary embodiments of the present disclosure.

[0095] For example, in some embodiments of the present disclosure, referring to FIG. 8 , the display substrate further includes an inorganic encapsulation layer 90 disposed between the LED light emitting unit 30 and the prism portion 60 .

[0096] For example, the inorganic encapsulation layer 90 may include n inorganic encapsulation sublayers that are alternately arranged, wherein two adjacent inorganic encapsulation sublayers among the n inorganic encapsulation sublayers have different refractive indices, and wherein n is a positive integer greater than or equal to 3.

[0097] 9A , in some embodiments of the present disclosure, the inorganic encapsulation layer may include three inorganic encapsulation sublayers arranged alternately, for example, a first inorganic encapsulation sublayer 901, a second inorganic encapsulation sublayer 902, and a third inorganic encapsulation sublayer 903. For example, the material of the first inorganic encapsulation sublayer 901 may include SiCN, the material of the second inorganic encapsulation sublayer 902 may include SiN, and the material of the third inorganic encapsulation sublayer 903 may include SiCN.

[0098] 9B , in some embodiments of the present disclosure, the inorganic encapsulation layer may include five alternating inorganic encapsulation sublayers, for example, a first inorganic encapsulation sublayer 901, a second inorganic encapsulation sublayer 902, a third inorganic encapsulation sublayer 903, a fourth inorganic encapsulation sublayer 904, and a fifth inorganic encapsulation sublayer 905. For example, the material of the first inorganic encapsulation sublayer 901 may include SiCN, the material of the second inorganic encapsulation sublayer 902 may include SiN, the material of the third inorganic encapsulation sublayer 903 may include SiCN, the material of the fourth inorganic encapsulation sublayer 904 may include SiN, and the material of the fifth inorganic encapsulation sublayer 905 may include SiCN.

[0099] The thickness of different inorganic encapsulation sublayers can be the same or different. For example, continuing to refer to Figure 10, the thickness of the first inorganic encapsulation sublayer 901 in the third direction D3 can be 80nm, the thickness of the second inorganic encapsulation sublayer 902 in the third direction D3 can be 40nm, the thickness of the third inorganic encapsulation sublayer 903 in the third direction D3 can be 1260nm, the thickness of the fourth inorganic encapsulation sublayer 904 in the third direction D3 can be 40nm, and the thickness of the fifth inorganic encapsulation sublayer 905 in the third direction D3 can be 80nm. By optimizing the number and thickness of the inorganic encapsulation sublayers, the protective effect of the inorganic encapsulation layer can be further improved, and the service life of the LED light-emitting unit can be increased.

[0100] It should be noted that the number and thickness of the inorganic encapsulation sub-layers included in the inorganic encapsulation layer can be specifically designed according to the actual encapsulation effect, and the embodiments of the present disclosure do not specifically limit this.

[0101] For example, in some embodiments of the present disclosure, the inorganic encapsulation layer 90 may include a high-refractive-index film layer. For example, the inorganic encapsulation layer 90 may include n high-refractive-index inorganic encapsulation sublayers, where n is a positive integer greater than or equal to 3. For example, the refractive index of the material of the even-numbered inorganic encapsulation sublayers among the n inorganic encapsulation sublayers may be greater than or equal to 1.85. For example, with continued reference to FIG9B , the second inorganic encapsulation sublayer 902 and the fourth inorganic encapsulation sublayer 904 may include SiN. Referring to FIG10 , the abscissa represents the relative ratio of SiH4:NH3, and the ordinate represents the refractive index of the SiN material. The two curves in FIG10 respectively show how the refractive index of the SiN material changes with the relative ratio of SiH4:NH3 in simulation calculations and actual fabrication, with the trends of the two curves substantially matching. During the SiN fabrication process, a high-refractive-index SiN film layer, for example, a SiN film layer with a refractive index of 2.0, can be obtained by adjusting parameters such as deposition power and gas flow rates, for example, by adjusting the relative ratio of SiH4:NH3.

[0102] By designing the inorganic encapsulation layer 90 with a high refractive index, the probability of total reflection of the LED light-emitting unit when passing through the inorganic encapsulation layer can be reduced, which is beneficial to improving the light extraction efficiency of the LED light-emitting unit and improving the display brightness of the display substrate.

[0103] For example, in some embodiments of the present disclosure, with continued reference to FIG8 , the prism portion 60 includes a top surface 610 that is away from the base substrate 1 , and the top surface 610 is a convex arc surface. By designing the top surface 610 of the prism portion as a convex arc surface, the light extraction efficiency of the prism portion 60 is improved, thereby improving the display brightness of the display substrate.

[0104] FIG. 11 is a schematic diagram showing a comparison of light output intensities of different prism diameters at different viewing angles according to some exemplary embodiments of the present disclosure.

[0105] For example, in some embodiments of the present disclosure, with reference to FIG8 and FIG11, different light emission intensities detected at different viewing angles of the light-emitting surface are shown when a prism portion 60 is added and the prism portion 60 has different diameters. In FIG11, the horizontal axis represents the viewing angles at different angles to the normal line perpendicular to the substrate, wherein the viewing angle parallel to the normal line is 0°, and the vertical axis represents the light emission intensity of the light-emitting surface corresponding to the case where there is no prism portion and the prism portion has different diameters. After the prism portion is added, the light emission intensity at the positive viewing angle of the light-emitting surface is significantly increased, wherein the positive viewing angle can include a viewing angle range of ±30° with respect to the normal line perpendicular to the substrate. For example, with reference to FIG11, when the diameter of the prism portion is 4um, that is, the radius of curvature of the convex arc surface of the prism portion is 2um, the light emission intensity of the display substrate at a positive viewing angle of ±30° is increased by 200% relative to the light emission intensity of the display substrate without a prism portion. When the diameter of the prism portion continues to increase, for example, to 4.2um, 4.4um or 4.6um, the light output intensity of the display substrate at a positive viewing angle of ±30° can be further increased, thereby achieving a high-brightness display. The light output intensity of the LED light-emitting unit 30 at different viewing angles can be adjusted by optimizing the curvature radius of the convex curved surface of the prism portion. The inventors have found through research that the greater the light output intensity at a positive viewing angle, the better the display effect. By increasing the curvature radius of the convex curved surface, the light output intensity of the LED light-emitting unit at a positive viewing angle can be increased, thereby improving the display effect of the display substrate. Exemplarily, the curvature radius of the convex curved surface can be greater than or equal to 2um. For example, the curvature radius of the convex curved surface can be 2.1um, 2.2um or 2.3um.

[0106] For example, in some embodiments of the present disclosure, while adding an encapsulation layer can better protect the display substrate, it also absorbs some blue light, slightly reducing the brightness at normal viewing angles for display substrates without a prism. Adding a prism above the encapsulation layer can focus photons, reducing crosstalk between adjacent pixels and achieving a greater proportion of light intensity gain at normal viewing angles.

[0107] FIG. 12 is a schematic diagram of crosstalk between adjacent pixels at different viewing angles according to some exemplary embodiments of the present disclosure.

[0108] In Micro-LED display substrates, due to the small distance between adjacent pixel units, crosstalk is prone to occur between adjacent pixels, and the crosstalk varies at different viewing angles. As the viewing angle increases, crosstalk between pixel units generally increases. This crosstalk affects the display quality of the display substrate and reduces the user experience. By providing a reflective layer between adjacent pixels, crosstalk between adjacent pixel units can be reduced, improving the display quality of the display substrate.

[0109] FIG. 13 is a schematic structural diagram of a reflective layer according to some exemplary embodiments of the present disclosure.

[0110] Exemplarily, in some embodiments of the present disclosure, the display substrate further includes: a third via hole VH3 located between the inorganic packaging layers 90 of adjacent LED light-emitting units 30; and a reflective layer 110 located in the third via hole VH3, wherein the reflective layer 110 is used to reflect at least a portion of the light emitted from the side by the LED light-emitting unit 30.

[0111] For example, in some embodiments of the present disclosure, the reflective layer 110 may include a metal reflective layer. For example, the metal reflective layer may include a combination of one or more common metals such as Al, Ag, or Mg / Ag alloys. The metal reflective layer may be prepared by evaporation or magnetron sputtering. Providing a metal reflective layer between adjacent pixels can serve to collect light and reduce crosstalk, thereby increasing the light intensity at the normal viewing angle of the display substrate and reducing crosstalk between adjacent pixel units, thereby achieving a high-brightness, high-resolution display effect.

[0112] For example, in some embodiments of the present disclosure, the reflective layer 110 may further include a black glue reflective layer. For example, the black glue may be applied using an automatic glue dispenser or printed using a 3D printer. Providing a black glue reflective layer between adjacent pixels effectively prevents light from a pixel at a large angle from entering adjacent pixels, thereby reducing crosstalk between adjacent pixel units.

[0113] Figure 14A is a schematic diagram of the structure of a reflective layer according to some other exemplary embodiments of the present disclosure; Figure 14B is a schematic diagram of the photon density distribution of a display substrate without a reflective layer according to some exemplary embodiments of the present disclosure; Figure 14C is a schematic diagram of the photon density distribution of a display substrate provided with the reflective layer in Figure 14A.

[0114] By way of example, in some embodiments of the present disclosure, the reflective layer 110 includes m inorganic reflective sublayers arranged alternately, and the difference in refractive index between two adjacent inorganic reflective sublayers among the m inorganic reflective sublayers is greater than or equal to 0.4, where m is a positive integer greater than or equal to 2. For example, referring to FIG14A , the reflective layer 110 includes two inorganic reflective sublayers, such as a first inorganic reflective sublayer 1101 and a second inorganic reflective sublayer 1102. By way of example, the material of the first inorganic reflective sublayer 1101 may include zirconium dioxide, the refractive index of which may be 2.13, and the material of the second inorganic reflective sublayer 1102 may include metallic zirconium, the refractive index of which may be 1.63.

[0115] In some embodiments, the reflective layer 110 may further include more inorganic reflective sublayers. For example, the reflective layer 110 may further include a third inorganic reflective sublayer and a fourth inorganic reflective sublayer. The material of the third inorganic reflective sublayer may include zirconium dioxide, and the material of the fourth inorganic reflective sublayer may include metallic zirconium.

[0116] For example, Figures 14B and 14C show a comparison of the photon distribution of a display substrate without a reflective layer and a display substrate with an inorganic reflective layer, where the horizontal axis represents the viewing angle range at different angles to the normal of the substrate, and the vertical axis represents the relative density of the photon distribution. By designing multiple alternating inorganic reflective sublayers and using two adjacent inorganic reflective sublayers with different refractive indices to form a resonant cavity, the photon density of different energy states can be redistributed. For example, the photon distribution can be changed from a loose distribution at ±60° to the normal of the substrate in Figure 14B to a focused distribution at ±30° to the normal of the substrate in Figure 14C, so that light of a specific wavelength can be emitted at a specific angle after conforming to the resonant cavity mode. By adding alternating inorganic reflective sublayers and adjusting the refractive index difference between adjacent inorganic reflective sublayers to be greater than or equal to 0.4, more light can be focused within the normal viewing angle range of ±30° to the normal of the substrate, thereby improving the light intensity in the normal viewing angle range and achieving a high-brightness and high-resolution display effect.

[0117] For example, the thicknesses of two adjacent inorganic reflective sub-layers may be the same or different. The material of the inorganic reflective layer may also include a combination of two or more of GaN, SiO2, SiN or SiON.

[0118] FIG. 15 is a schematic structural diagram of a display panel according to some exemplary embodiments of the present disclosure.

[0119] 15 , the display panel 200 may include the display substrate 100. It should be understood that the display panel has the same advantageous effects as the display substrate provided in the aforementioned embodiment.

[0120] FIG. 16 is a schematic structural diagram of a display device according to some exemplary embodiments of the present disclosure.

[0121] Optionally, embodiments of the present disclosure further provide a display device. Referring to FIG. 16 , the display device 300 may include the display substrate 100 or the display panel 200 described above. The display device may include, but is not limited to, electronic paper, mobile phones, tablet computers, monitors, laptop computers, digital photo frames, navigation systems, and any other product or component with a display function. It should be understood that this display device has the same beneficial effects as the display substrate or display panel provided in the aforementioned embodiments.

[0122] FIG17 is a flow chart of a method for preparing a display substrate according to some exemplary embodiments of the present disclosure; and FIG18 to FIG26 are schematic diagrams of partial structures of the display substrate at different stages in the preparation process of FIG17 .

[0123] Illustratively, in some embodiments of the present disclosure, the method for preparing a display substrate includes steps S101 to S109.

[0124] In step S101 , referring to FIG. 18 , a first electrode material layer 2 , a first reflective electrode material layer 3 and a first bonding material layer 4 are sequentially deposited on a base substrate 1 .

[0125] In step S102, referring to FIG. 19 , a patterning process is performed on the first electrode material layer 2, the first reflective electrode material layer 3, and the first bonding material layer 4 to form an array-arranged reflective bonding structure 20, wherein the reflective bonding structure 20 includes a first electrode 21 located in the first electrode material layer 2, a first reflective electrode 22 located in the first reflective electrode material layer 3, and a first bonding portion 23 located in the first bonding material layer 4.

[0126] In step S103 , referring to FIG. 20 , a semiconductor buffer material layer 6 , a first semiconductor material layer 7 , a quantum well material layer 8 and a second semiconductor material layer 9 are epitaxially grown on the entire surface of the wafer 5 to form an LED epitaxial layer.

[0127] In step S104 , referring to FIG. 21 , a second bonding material layer 10 is deposited on the entire surface of the second semiconductor material layer 9 .

[0128] In step S105 , referring to FIG. 22 , a bonding process is performed on the entire second bonding material layer 10 and the array-arranged reflective bonding structures 20 .

[0129] In step S106 , referring to FIG. 23 , after the bonding process is completed, the wafer 5 is peeled off, the semiconductor buffer material layer 6 is removed, and the first semiconductor material layer 7 is thinned to form a thinned LED epitaxial layer 32 .

[0130] In step S107, referring to Figure 24, a patterning process is performed on the thinned LED epitaxial layer 32 and the second bonding material layer 10 to form a first via hole VH1, and a plurality of LED light-emitting portions arranged in an array corresponding to the reflective bonding structure are formed, wherein the LED light-emitting portion includes a second bonding portion 31 and an LED epitaxial layer 32.

[0131] In step S108, referring to FIG. 25, an insulating layer is formed on a side of the LED epitaxial layer away from the substrate, and a patterning process is performed on the insulating layer to form a second via hole VH2 exposing the LED epitaxial layer, and to form an isolation portion 40 between adjacent LED light-emitting units.

[0132] In step S109 , referring to FIG. 26 , a second electrode layer 33 is formed on a side of the insulating layer away from the base substrate.

[0133] By forming an array of first bonding sections on the substrate and forming a second bonding material layer on the LED epitaxial layer, the entire surface of the LED epitaxial layer is made of the same material as the first bonding sections, thereby achieving bonding between the LED epitaxial layer and the substrate without the need for alignment, thereby improving bonding efficiency. Furthermore, after bonding is completed, a micro-array design of the LED epitaxial layer and the second bonding material layer is achieved through a patterning process, ensuring that the orthographic projection of the second bonding section on the substrate lies within the orthographic projection of the first bonding section on the substrate, forming an array of LED light-emitting units, thereby achieving a high-resolution display design.

[0134] Illustratively, in some embodiments of the present disclosure, the method for preparing a display substrate further includes, after forming the second electrode layer, continuing to form a combination of one or more of a metal conductive layer, an inorganic encapsulation layer, or a prism portion.

[0135] FIG27 is a flow chart of forming an inorganic encapsulation layer and a prism portion according to some exemplary embodiments of the present disclosure; and FIG28 to FIG32 are schematic diagrams of partial structures of a display substrate at different stages in the preparation process of FIG27 .

[0136] Illustratively, in some embodiments of the present disclosure, the method for preparing a display substrate further includes steps S110 to S114.

[0137] In step S110, with reference to Figures 9A, 9B and 28, a first inorganic encapsulation sublayer 901, a second inorganic encapsulation sublayer 902 and a third inorganic encapsulation sublayer 903 are alternately formed on the side of the LED light-emitting unit 30 away from the substrate substrate to form an inorganic encapsulation layer 90 comprising n inorganic encapsulation sublayers, where n is a positive integer greater than or equal to 3.

[0138] In step S111 , referring to FIG. 29 , a first prism layer 11 is formed entirely on a side of the inorganic encapsulation layer 90 away from the base substrate 1 .

[0139] For example, the first prism layer may be made of a high-refractive-index silicon nitride material, formed using low-temperature chemical vapor deposition (CVD) thin-film technology. The refractive index of the silicon nitride film can be adjusted by adjusting parameters such as the power, SiH4 and NH3 gas flow rates, and the like during the silicon nitride deposition process. For example, by increasing the relative ratio of SiH4 / NH3, more Si atoms can be provided in the reaction chamber, meaning more Si atoms react with the surplus N atoms, increasing the concentration of the reaction precursors. This allows the gases to fully react on the substrate surface, forming a dense film, thereby increasing the refractive index of the film.

[0140] In step S112 , referring to FIG. 30 , a photoresist layer is formed on the entire side of the first prism layer away from the base substrate, and a patterning process is performed on the photoresist layer to form a photoresist remaining portion 12 corresponding to the LED light emitting unit 30 .

[0141] In step S113 , referring to FIG. 31 , a thermal reflow process is performed on the photoresist remaining portion 12 to form a photoresist prism portion 13 .

[0142] In step S114 , referring to FIG. 32 , the photoresist prism portion 13 and the first prism layer 11 are etched simultaneously until the photoresist prism portion 13 is removed, and prism portions 60 arranged in an array corresponding to the LED light emitting units are formed.

[0143] By adding the prism part, the light intensity of the display substrate at a normal viewing angle can be increased, and the crosstalk between adjacent pixels can be reduced, which is conducive to achieving high-brightness and high-resolution display.

[0144] For example, in some embodiments of the present disclosure, the larger the radius of the convex arc surface of the prism portion is, the more the light intensity at a normal viewing angle is improved, and the higher the display brightness of the display substrate is.

[0145] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined in the claims and their equivalents.

Claims

1. A display substrate, characterized in that: The display substrate comprises: a base substrate, the base substrate comprising a display area and a peripheral area, the peripheral area at least partially surrounding the display area; and A plurality of pixel units are located in a display area of the substrate, wherein the plurality of pixel units are arrayed in the display area along a first direction and a second direction, at least one of the pixel units includes a reflective bonding structure and an LED light-emitting unit, wherein the first direction and the second direction intersect, The reflective bonding structure includes: a first electrode disposed on the base substrate; a first reflective electrode disposed on a side of the first electrode away from the base substrate; and a first bonding portion disposed on a side of the first reflective electrode away from the base substrate; The LED light emitting unit includes: a second bonding portion provided on a side of the first bonding portion away from the substrate; an LED epitaxial layer provided on a side of the second bonding portion away from the substrate; and a second electrode provided on a side of the LED epitaxial layer away from the substrate. wherein the orthographic projection of the second bonding portion on the base substrate is located within the orthographic projection of the first bonding portion on the base substrate; and The first bonding portion and the second bonding portion include a same material.

2. The display substrate according to claim 1, wherein: The first bonding portion and the second bonding portion include a same material selected from ITO or IZO.

3. The display substrate according to claim 2, wherein: The first bonding portion includes a first slope angle, and the first slope angle ranges from 70° to 85°; and / or, The second bonding portion includes a second slope angle, and the second slope angle ranges from 70° to 85°.

4. The display substrate according to claim 3, wherein: The material of the first electrode is one of ITO and IZO; and / or, The material of the first reflective electrode is silver.

5. The display substrate according to any one of claims 1 to 4, wherein: The display substrate further includes an isolation portion located between adjacent pixel units, the isolation portion covering at least a portion of a surface of the LED epitaxial layer away from the base substrate, a side wall of the reflective bonding structure, and a side wall of the LED light-emitting unit.

6. The display substrate according to claim 5, wherein: The isolation portion has a first thickness in a third direction, wherein the third direction is perpendicular to the first direction and the second direction; The reflective bonding structure has a second thickness in the third direction; The second bonding portion has a third thickness in the third direction; and The LED epitaxial layer has a fourth thickness in the third direction, The first thickness is greater than the sum of the second thickness, the third thickness and the fourth thickness.

7. The display substrate according to claim 5 or 6, wherein: The LED epitaxial layer includes: a second semiconductor layer provided on a side of the second bonding portion away from the substrate; a quantum well layer provided on a side of the second semiconductor layer away from the substrate; and a first semiconductor layer provided on a side of the quantum well layer away from the substrate; and The isolation portion includes an opening, and the opening exposes at least a portion of a surface of the first semiconductor layer away from the substrate.

8. The display substrate according to any one of claims 5 to 7, wherein: The second electrode includes a main body portion and a second conductive connecting portion, the orthographic projection of the second conductive connecting portion on the base substrate coincides with the orthographic projection of the isolation portion on the base substrate, and the second electrodes of two adjacent pixel units are electrically connected via the second conductive connecting portion. The main body portion has a fifth thickness in the third direction, the second conductive connection portion has a sixth thickness in the third direction, and the fifth thickness is greater than the sixth thickness.

9. The display substrate according to claim 8, wherein: The display substrate further includes a metal conductive layer disposed on a side of the second electrode away from the base substrate. wherein the orthographic projection of the metal conductive layer on the base substrate is located within the orthographic projection of the second conductive connecting portion on the base substrate; and The metal conductive layer includes a plurality of first conductive sub-portions arranged along a first direction and a plurality of first conductive sub-portions arranged along a second direction. The plurality of first conductive sub-sections and the plurality of second conductive sub-sections are electrically connected to each other.

10. The display substrate according to claim 9, wherein: The metal conductive layer includes a first metal conductive sublayer disposed on a side of the second electrode away from the base substrate; a second metal conductive sublayer disposed on a side of the first metal conductive sublayer away from the base substrate; and a third metal conductive sublayer disposed on a side of the second metal conductive sublayer away from the base substrate. wherein the orthographic projection of the second metal conductive sublayer on the base substrate is located within the orthographic projection of the first metal conductive sublayer on the base substrate; and The orthographic projection of the third metal conductive sublayer on the base substrate is located within the orthographic projection of the second metal conductive sublayer on the base substrate.

11. The display substrate according to any one of claims 1 to 10, wherein: The display substrate further includes a prism portion disposed on a side of the second electrode away from the base substrate. The orthographic projection of the prism portion on the base substrate at least partially overlaps with the orthographic projection of the LED epitaxial layer on the base substrate.

12. The display substrate according to claim 11, wherein: The display substrate further includes a first conductive transition portion and a second conductive transition portion located in the peripheral area, wherein the first conductive transition portion and the second conductive transition portion are electrically connected, wherein: The first conductive transition portion includes a first conductive transition sub-portion, a second conductive transition sub-portion, a third conductive transition sub-portion and a fourth conductive transition sub-portion, wherein: The first conductive transfer sub-portion and the first electrode are located in the same layer; The second conductive adapter portion and the first reflective electrode are located in the same layer; The third conductive transfer sub-portion and the first bonding portion are located in the same layer; and The fourth conductive transfer sub-portion and the second bonding portion are located in the same layer; and The second conductive transition sub-section includes a fifth conductive transition sub-section and a sixth conductive transition sub-section, wherein: The fifth conductive transfer sub-portion and the second electrode are located in the same layer; and The sixth conductive transfer sub-portion and the metal conductive layer are located on the same layer.

13. The display substrate according to claim 11 or 12, wherein: The display substrate further includes an inorganic packaging layer disposed between the LED light emitting unit and the prism portion.

14. The display substrate according to claim 13, wherein: The inorganic encapsulation layer includes n inorganic encapsulation sub-layers arranged alternately, wherein: The refractive indexes of two adjacent inorganic encapsulation sublayers in the n inorganic encapsulation sublayers are different, wherein n is a positive integer greater than or equal to 3.

15. The display substrate according to claim 14, wherein: The refractive index of the material of the inorganic encapsulation sublayers in the even-numbered layers among the n inorganic encapsulation sublayers is greater than or equal to 1.

85.

16. The display substrate according to claim 11, wherein The prism portion includes a top surface away from the base substrate, and the top surface is a convex arc surface.

17. The display substrate according to claim 16, wherein: The curvature radius of the convex arc surface is greater than or equal to 2 μm.

18. The display substrate according to any one of claims 13 to 17, wherein: The display substrate further includes: a third via hole located between the inorganic packaging layers of adjacent LED light-emitting units; and a reflective layer located in the third via hole, wherein the reflective layer is used to reflect at least a portion of the light emitted from the LED light-emitting unit and emitted from the side.

19. The display substrate according to claim 18, wherein: The reflective layer includes m inorganic reflective sublayers that are alternately arranged, and a difference in refractive index between two adjacent inorganic reflective sublayers among the m inorganic reflective sublayers is greater than or equal to 0.4, wherein m is a positive integer greater than or equal to 2.

20. The display substrate according to claim 18, wherein The reflective layer includes a metal reflective layer or a black plastic reflective layer.

21. A display panel, wherein: The display panel includes the display substrate according to any one of claims 1 to 20.

22. A display device, wherein: The display device includes the display substrate according to any one of claims 1 to 20 or the display panel according to claim 21.

23. A method for preparing a display substrate, characterized in that: The method comprises: Depositing a first electrode material layer, a first reflective electrode material layer and a first bonding material layer in sequence on the base substrate; Performing a patterning process on the first electrode material layer, the first reflective electrode material layer, and the first bonding material layer to form an array-arranged reflective bonding structure, wherein the reflective bonding structure includes a first electrode located in the first electrode material layer, a first reflective electrode located in the first reflective electrode material layer, and a first bonding portion located in the first bonding material layer; Epitaxially growing a semiconductor buffer material layer, a first semiconductor material layer, a quantum well material layer, and a second semiconductor material layer on the entire surface of the wafer to form an LED epitaxial layer; Depositing a second bonding material layer on the entire surface of the second semiconductor material layer; performing a bonding process on the entire second bonding material layer and the reflective bonding structures arranged in an array; After the bonding process is completed, the wafer is peeled off, the semiconductor buffer material layer is removed, and the first semiconductor material layer is thinned to form a thinned LED epitaxial layer; Performing a patterning process on the thinned LED epitaxial layer and the second bonding material layer to form a first via hole and a plurality of LED light-emitting portions arranged in an array corresponding to the reflective bonding structure; forming an insulating layer on a side of the LED epitaxial layer away from the substrate, and performing a patterning process on the insulating layer to form a second via hole exposing the LED epitaxial layer, and forming an isolation portion between adjacent LED light-emitting units; and A second electrode layer is formed on a side of the insulating layer away from the base substrate.

24. The method of claim 23, wherein: The method further comprises: Alternatingly forming a first inorganic encapsulation sublayer and a second inorganic encapsulation sublayer on a side of the LED light-emitting unit away from the base substrate to form an inorganic encapsulation layer comprising n inorganic encapsulation sublayers, wherein n is a positive integer greater than or equal to 3; forming a first prism layer on a whole surface on a side of the inorganic encapsulation layer away from the base substrate; forming a whole-surface photoresist layer on a side of the first prism layer away from the base substrate, and performing a patterning process on the photoresist layer to form a photoresist reserved portion corresponding to the LED light-emitting unit; Applying a thermal reflow process to the photoresist retaining portion to form a photoresist prism portion; and The photoresist prism portion and the first prism layer are etched simultaneously until the photoresist prism portion is removed, and prism portions arranged in an array corresponding to the LED light-emitting units are formed.

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