Light-emitting chip and preparation method thereof, display substrate and preparation method thereof, and display device

Abstract

The invention discloses a light-emitting chip and a preparation method thereof, a sub-millimeter diode light-emitting chip, a light-emitting chip array, a display substrate and a display device. The light-emitting chip comprises: an LED light-emitting unit (20) configured to emit light of a first wavelength; the light conversion unit (30) is arranged on the light-emitting side of the LED light-emitting unit (20), the light conversion unit (30) is configured to convert light of a first wavelength into light of a second wavelength, the color of the light of the first wavelength is different from that of the light of the second wavelength, and the light conversion unit (30) comprises a first bonding layer (301) arranged on the light-emitting side of the LED light-emitting unit (20) and a second bonding layer (302) arranged on the light-emitting side of the LED light-emitting unit (20); the first quantum well layer (302) is arranged on one side, far away from the LED light-emitting unit (20), of the first bonding layer (301); the first semiconductor layer (303) is arranged on the side, away from the LED light-emitting unit (20), of the first quantum well layer (302), and the first quantum well layer (302) is configured to emit light of a second wavelength under excitation of the light of the first wavelength.

Description

Light-emitting chip and manufacturing method thereof, display substrate and manufacturing method thereof, and display device Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a light-emitting chip and a manufacturing method thereof, a display substrate and a manufacturing method thereof, and a display device. Background Art

[0002] With the development of display technology, higher demands are being placed on the brightness and resolution of display products. Among them, sub-millimeter diode (Mini Light Emitting Diode, English abbreviation Mini LED) light-emitting chips and micro light-emitting diode (Micro LED) light-emitting chips are widely used in the field of high-resolution display.

[0003] However, as the size of light-emitting chips decreases, their efficiency decreases. This is especially true for red and green LED chips, where efficiency drops significantly as chip size decreases, significantly impacting the performance of display products. Creating high-efficiency, multi-color light-emitting chips during the miniaturization process is a key research topic for researchers.

[0004] Summary of the Invention

[0005] In a first aspect, a light-emitting chip is provided, wherein the light-emitting chip includes: an LED light-emitting unit, the LED light-emitting unit being configured to emit light of a first wavelength; and a light conversion unit arranged on a light-emitting side of the LED light-emitting unit, the light conversion unit being configured to convert the light of the first wavelength into light of a second wavelength, wherein the light of the first wavelength and the light of the second wavelength have different colors, and the light conversion unit includes: a first bonding layer arranged on the light-emitting side of the LED light-emitting unit; a first quantum well layer arranged on a side of the first bonding layer away from the LED light-emitting unit; and a first semiconductor layer arranged on a side of the first quantum well layer away from the LED light-emitting unit, wherein the first quantum well layer is configured to emit light of the second wavelength under the excitation of the light of the first wavelength.

[0006] According to some exemplary embodiments, the LED light-emitting unit includes: a first buffer layer arranged on a side of the first bonding layer away from the first quantum well layer; a second semiconductor layer arranged on a side of the first buffer layer away from the first quantum well layer; a second quantum well layer arranged on a side of the second semiconductor layer away from the first quantum well layer; a third semiconductor layer arranged on a side of the second quantum well layer away from the first quantum well layer; and a first electrode arranged on a side of the third semiconductor layer away from the first quantum well layer.

[0007] According to some exemplary embodiments, the second semiconductor layer includes a second electrode connection portion that is not covered by the second quantum well layer; the LED light-emitting unit also includes: a second electrode arranged on a side of the second electrode connection portion away from the first quantum well layer; and a first insulating layer arranged on a side of both the first electrode and the second electrode away from the first quantum well layer, wherein the first insulating layer includes a first via hole exposing at least a portion of the first electrode and a second via hole exposing at least a portion of the second electrode; and the LED light-emitting unit also includes: a first lead-out electrode and a second lead-out electrode, wherein the first lead-out electrode is electrically connected to the first electrode through the first via hole; and the second lead-out electrode is electrically connected to the second electrode through the second via hole.

[0008] According to some exemplary embodiments, an orthographic projection of the second quantum well layer on the first bonding layer falls within an orthographic projection of the first quantum well layer on the first bonding layer.

[0009] According to some exemplary embodiments, the thickness of the first semiconductor layer is greater than or equal to 500 nm and less than or equal to 5 um; and / or the number of quantum well pairs in the first quantum well layer is greater than or equal to 10; and / or the thickness of the first bonding layer is greater than or equal to 10 nm and less than or equal to 5 um.

[0010] According to some exemplary embodiments, the material of the first semiconductor layer includes AlGaInP; and / or the material of the first quantum well layer includes AlGaInP quantum well; and / or the material of the first bonding layer includes at least one of SiO2, benzocyclobutene or SU8 negative photoresist.

[0011] According to some exemplary embodiments, the first wavelength of light emitted by the LED light-emitting unit includes light with a wavelength greater than or equal to 200nm and less than or equal to 495nm; and / or the second wavelength of light includes light with a wavelength greater than or equal to 620nm and less than or equal to 760nm.

[0012] According to some exemplary embodiments, the light-emitting chip further includes a reflective layer, which covers at least a portion of the side wall of the LED light-emitting unit, wherein the reflective layer includes a first reflective sub-layer, a second reflective sub-layer and a third reflective sub-layer; the side wall of the LED light-emitting unit includes a first side wall, a second side wall and a third side wall; the first reflective sub-layer covers at least a portion of the first side wall; the second reflective sub-layer covers at least a portion of the second side wall; and the third reflective sub-layer covers at least a portion of the third side wall, wherein the first side wall includes a side wall of the side wall of the LED light-emitting unit that is close to the first lead-out electrode and away from the second lead-out electrode; the second side wall includes a side wall of the side wall of the LED light-emitting unit that is located between the first lead-out electrode and the second lead-out electrode; and the third side wall includes a side wall of the side wall of the LED light-emitting unit that is close to the second lead-out electrode and away from the first lead-out electrode.

[0013] According to some exemplary embodiments, the light reflecting layer includes a first passivation layer, a first metal light reflecting layer, and a second passivation layer.

[0014] According to some exemplary embodiments, the light emitting chip further includes a first inorganic reflective layer disposed between the first semiconductor layer and the first quantum well layer, the first inorganic reflective layer including a stacked layer of a GaAs layer and an AlAs layer.

[0015] According to some exemplary embodiments, the material of the first electrode includes ITO; and / or the material of the second electrode includes one of Ti or Cr; and / or the first lead-out electrode and the second lead-out electrode are located in the same layer, wherein the material of the first lead-out electrode and the second lead-out electrode includes an alloy of one or more combinations of Ti, Al, Au, Sn, Ni or Pt, or a stack of multiple combinations.

[0016] In a second aspect, a sub-millimeter diode light-emitting chip is provided, wherein the sub-millimeter diode light-emitting chip includes: a second substrate; a second bonding layer arranged on the second substrate; and a light-emitting chip arranged on a side of the second bonding layer away from the second substrate, wherein the light-emitting chip includes a light-emitting chip as described in any one of the foregoing, wherein the second substrate is located on the light-emitting side of the light-emitting chip.

[0017] In a third aspect, a light-emitting chip array is provided, wherein the light-emitting chip array includes: a first substrate; a third bonding layer arranged on the first substrate; and a plurality of light-emitting chips arranged in an array on a side of the third bonding layer away from the first substrate, wherein the light-emitting chip includes a light-emitting chip as described in any one of the foregoing.

[0018] In a fourth aspect, a method for preparing a light-emitting chip is provided, wherein the method comprises: depositing a first buffer material layer, a second semiconductor material layer, a second quantum well material layer and a third semiconductor material layer in sequence on a first wafer to form an LED epitaxial layer; forming a first electrode material layer on a side of the LED epitaxial layer away from the first wafer; performing a composition process on the LED epitaxial layer and the first electrode material layer to form a mesa not covered by the second quantum well material layer on the second semiconductor material layer; forming a second electrode material layer on a side of the mesa of the second semiconductor material layer not covered by the second quantum well material layer away from the first wafer; forming a first insulating material layer on a side of the first electrode material layer and the second electrode material layer away from the first wafer, and performing a composition process on the first insulating material layer to form a first via exposing a portion of the first electrode material layer and a second via exposing a portion of the second electrode material layer; forming a metal conductive material layer on a side of the first insulating material layer away from the first wafer, and patterning the metal conductive material layer. A composition process is performed on the material layer to form a first lead-out electrode electrically connected to the first electrode material layer through the first via hole and a second lead-out electrode electrically connected to the second electrode material layer through the second via hole, so as to form an LED light-emitting unit located on the first chip; a composition process is performed on the LED light-emitting unit to form a plurality of LED light-emitting units located on the first chip; a third bonding material layer is formed on the side of the metal conductive material layer away from the first chip; a first substrate is formed on the side of the third bonding material layer away from the first chip; the first chip is removed to form a plurality of LED light-emitting units located on the first substrate; and a second buffer material layer, a first semiconductor material layer and a first quantum well material layer are deposited in sequence on the second chip to form a light conversion unit located on the second chip; a first bonding material layer is formed between the first buffer material layer and the first quantum well material layer to achieve bonding of the plurality of LED light-emitting units to the light conversion unit; and the second chip and the second buffer material layer are removed to form a light-emitting chip located on the first substrate.

[0019] According to some exemplary embodiments, performing a composition process on the LED light-emitting unit to form a plurality of LED light-emitting units located on the first chip includes: performing a composition process on the LED light-emitting unit to form a plurality of sub-millimeter diode light-emitting units located on the first chip; the method also includes: forming a second bonding material layer on a side of the first semiconductor layer away from the first substrate; forming a second substrate on a side of the second bonding material layer away from the first substrate; removing the first substrate and the third bonding material layer; performing a composition process on the second substrate, the second bonding material layer, the first semiconductor material layer, the first quantum well material layer and the first bonding material layer to form a plurality of independent sub-millimeter diode light-emitting chips.

[0020] According to some exemplary embodiments, performing a composition process on the LED light-emitting unit to form a plurality of LED light-emitting units located on the first chip includes: performing a composition process on the LED light-emitting unit to form a plurality of micro-diode light-emitting units located on the first chip; the method also includes: performing a composition process on the first semiconductor material layer, the first quantum well material layer and the first bonding material layer to form a plurality of micro-diode light-emitting chip arrays located on the first substrate.

[0021] In a fifth aspect, a display substrate is provided, wherein the display substrate includes: a base substrate; and a plurality of pixel units arranged on the base substrate, at least one pixel unit including a first sub-pixel, a second sub-pixel and a third sub-pixel, wherein the first sub-pixel, the second sub-pixel and the third sub-pixel respectively include an LED light-emitting unit and a light guide layer, the LED light-emitting unit is configured to emit light of a first wavelength, the light guide layer includes a second light conversion layer arranged on the light-emitting side of the LED light-emitting unit of the second sub-pixel, the second light conversion layer is configured to convert the light of the first wavelength into light of a second wavelength, wherein the orthographic projection of the LED light-emitting unit of the second sub-pixel on the base substrate falls within the orthographic projection of the second light conversion layer on the base substrate; the light guide layer also includes a third light conversion layer arranged on the light-emitting side of the LED light-emitting unit of the third sub-pixel, the third light conversion layer is configured to convert the light of the first wavelength into light of a third wavelength, wherein the orthographic projection of the LED light-emitting unit of the third sub-pixel on the base substrate falls within the orthographic projection of the third light conversion layer on the base substrate, and wherein the colors of the light of the first wavelength, the second wavelength and the third wavelength are different.

[0022] According to some exemplary embodiments, the material of the second light conversion layer includes red light quantum dots; and / or the material of the third light conversion layer includes green light quantum dots.

[0023] According to some exemplary embodiments, the light guide layer also includes a first light guide layer arranged on the light emitting side of the LED light emitting unit of the first sub-pixel, wherein the orthographic projection of the LED light emitting unit of the first sub-pixel on the substrate falls within the orthographic projection of the first light guide layer on the substrate; and the material of the first light guide layer includes scattering particles.

[0024] According to some exemplary embodiments, the light guiding layer further includes a first light conversion layer arranged on the light emitting side of the LED light emitting unit of the first sub-pixel, the first light conversion layer being configured to convert the light of the first wavelength into light of a fourth wavelength, wherein the colors of the light of the first wavelength and the light of the fourth wavelength are different, wherein the material of the first light conversion layer includes blue light quantum dots; and the orthographic projection of the LED light emitting unit of the first sub-pixel on the substrate falls within the orthographic projection of the first light conversion layer on the substrate.

[0025] According to some exemplary embodiments, the display substrate further includes a second dielectric layer located on a side of the light guide layer away from the base substrate, wherein the second dielectric layer includes a main portion and a spacer portion, and the spacer portion is located in a gap between the light guide layers of adjacent sub-pixels; the orthographic projection of the second dielectric layer on the base substrate does not overlap with the orthographic projection of the LED light-emitting unit of the first sub-pixel on the base substrate; and the orthographic projection of each of the LED light-emitting unit of the second sub-pixel and the LED light-emitting unit of the third sub-pixel on the base substrate falls within the orthographic projection of the main portion of the second dielectric layer on the base substrate.

[0026] According to some exemplary embodiments, the display substrate further includes a second dielectric layer located on a side of the light guide layer away from the base substrate, wherein the second dielectric layer includes a main portion and a spacer portion, and the spacer portion is located in a gap between the light guide layers of adjacent sub-pixels; and the orthographic projection of each of the LED light-emitting unit of the first sub-pixel, the LED light-emitting unit of the second sub-pixel, and the LED light-emitting unit of the third sub-pixel on the base substrate falls within the orthographic projection of the main portion of the second dielectric layer on the base substrate.

[0027] According to some exemplary embodiments, the second dielectric layer includes a stacked structure of a SiO2 layer and a TiO2 layer; or, the second dielectric layer includes a stacked structure of a SiO2 layer and a NbO2 layer; and / or, the second dielectric layer has a third thickness in a direction perpendicular to the substrate, and the third thickness is less than or equal to 5um.

[0028] According to some exemplary embodiments, the display substrate further includes a first dielectric layer disposed between the LED light-emitting unit and the light guide layer, wherein the first dielectric layer includes a stacked structure of a SiO2 layer and a TiO2 layer; or, the first dielectric layer includes a stacked structure of a SiO2 layer and a NbO2 layer; and / or, the first dielectric layer has a fourth thickness in a direction perpendicular to the substrate, and the fourth thickness is less than or equal to 5 um.

[0029] According to some exemplary embodiments, the display substrate further includes a black glue layer disposed on a side of the second dielectric layer away from the base substrate, wherein the black glue layer is located between adjacent sub-pixels and is configured to reflect at least a portion of light emitted from the sub-pixels toward a side of an adjacent sub-pixel.

[0030] In a sixth aspect, a display device is provided, wherein the display device includes a display substrate as described in any one of the above.

[0031] In a seventh aspect, a method for preparing a display substrate is provided, wherein the method includes: forming a plurality of LED light-emitting units on a base substrate; forming a first dielectric material layer on a side of the plurality of LED light-emitting units away from the base substrate; depositing different light-guiding material layers in multiple steps on a side of the first dielectric material layer away from the base substrate and performing a patterning process to form light-guiding material layers corresponding to different LED light-emitting units; forming a second dielectric layer on a side of the light-guiding material layer away from the base substrate and performing a patterning process; forming a black glue layer on a side of the second dielectric layer away from the base substrate and performing a patterning process to form the display substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0033] FIG1 is a schematic structural diagram of a light-emitting chip according to some exemplary embodiments of the present disclosure;

[0034] 2 is a projection relationship diagram of a first quantum well layer and a second quantum well layer in a light-emitting chip according to some exemplary embodiments of the present disclosure;

[0035] FIG3A is a schematic diagram of the structure of a light-emitting chip according to some exemplary embodiments of the present disclosure; FIG3B is a schematic diagram of the structure of a light-reflecting layer in a light-emitting chip according to some exemplary embodiments of the present disclosure;

[0036] FIG4 is a schematic structural diagram of a light-emitting chip according to some exemplary embodiments of the present disclosure;

[0037] FIG5 is a schematic structural diagram of a sub-millimeter diode light-emitting chip according to some exemplary embodiments of the present disclosure;

[0038] FIG6 is a schematic structural diagram of a light-emitting chip array according to some exemplary embodiments of the present disclosure;

[0039] FIG7 is a flow chart of a method for preparing a light-emitting chip according to some exemplary embodiments of the present disclosure; FIG8 to FIG20 are schematic diagrams of partial structures of the light-emitting chip at different stages of the preparation process of FIG7 ;

[0040] FIG21 is a flow chart of a method for preparing a sub-millimeter diode light-emitting chip according to some exemplary embodiments of the present disclosure; FIG22 to FIG25 are schematic diagrams of partial structures of the sub-millimeter diode light-emitting chip at different stages of the preparation process of FIG21 ;

[0041] FIG26 is a schematic structural diagram of a light-emitting chip array according to some exemplary embodiments of the present disclosure;

[0042] FIG27 is a schematic plan view of a display substrate according to some exemplary embodiments of the present disclosure; FIG28 is a schematic partial interface view taken along line AA′ in the display substrate of FIG27 according to some exemplary embodiments of the present disclosure;

[0043] FIG. 29 is a partial schematic diagram of an interface taken along line AA′ in the display substrate of FIG. 27 according to some other exemplary embodiments of the present disclosure;

[0044] FIG30 is a schematic diagram of a partial interface taken along line AA′ in the display substrate of FIG27 according to some other exemplary embodiments of the present disclosure; FIG31 is a schematic diagram of a partial interface taken along line AA′ in the display substrate of FIG27 according to some other exemplary embodiments of the present disclosure;

[0045] FIG32 is a schematic structural diagram of a display device according to some exemplary embodiments of the present disclosure;

[0046] FIG33 is a flow chart of manufacturing a display substrate according to some exemplary embodiments of the present disclosure; and FIG34 to FIG38 are schematic diagrams of partial structures of the display substrate at different stages in the manufacturing process of FIG33 .

[0047] 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

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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 40 microns.

[0056] LEDs can be used to make mini LED and Micro LED displays due to their high refresh rate, high brightness, active light-emitting mode, and miniaturization capabilities. However, as the size of the light-emitting chip decreases, the efficiency of the light-emitting chip decreases, which has a significant impact on the performance of the display product. The efficiency of red LED light-emitting chips decreases particularly sharply as the size decreases. Existing red LED light-emitting chips are typically made of AlGaInP materials. Since the electron drift rate of AlGaInP system materials is higher than that of GaN system materials, the efficiency of red LED light-emitting chips decreases significantly as the chip size decreases, which has a significant impact on the performance of the display product. How to prepare high-efficiency light-emitting chips in multiple colors during the miniaturization of light-emitting chips is an urgent problem that researchers need to solve.

[0057] In an embodiment of the present disclosure, a light-emitting chip is provided, wherein the light-emitting chip includes: an LED light-emitting unit, the LED light-emitting unit being configured to emit light of a first wavelength; and a light conversion unit arranged on a light-emitting side of the LED light-emitting unit, the light conversion unit being configured to convert the light of the first wavelength into light of a second wavelength, wherein the light of the first wavelength and the light of the second wavelength have different colors, and the light conversion unit includes: a first bonding layer arranged on the light-emitting side of the LED light-emitting unit; a first quantum well layer arranged on a side of the first bonding layer away from the LED light-emitting unit; and a first semiconductor layer arranged on a side of the first quantum well layer away from the LED light-emitting unit, wherein the first quantum well layer is configured to emit light of the second wavelength under the excitation of the light of the first wavelength.

[0058] By combining a small-size blue light LED or a small-size ultraviolet LED with an inorganic quantum well structure, a high-efficiency small-size blue light LED or a small-size ultraviolet LED is used to generate light of a first wavelength, and then the first wavelength of light is used to excite the inorganic quantum well structure to generate light of a second wavelength, wherein the second wavelength of light may include red light, thereby forming a small-size red light LED chip, which can effectively improve the efficiency and stability of the small-size red light LED chip.

[0059] FIG1 is a schematic structural diagram of a light-emitting chip according to some exemplary embodiments of the present disclosure.

[0060] 1 , a light-emitting chip 100 includes an LED light-emitting unit 20 configured to emit light of a first wavelength λ1; and a light conversion unit 30 disposed on the light-emitting side of the LED light-emitting unit 20, configured to convert the light of the first wavelength λ1 into light of a second wavelength λ2, wherein the light of the first wavelength λ1 and the light of the second wavelength λ2 have different colors. The light conversion unit 30 includes a first bonding layer 301 disposed on the light-emitting side of the LED light-emitting unit 20; a first quantum well layer 302 disposed on a side of the first bonding layer 301 away from the LED light-emitting unit 20; and a first semiconductor layer 303 disposed on a side of the first quantum well layer 302 away from the LED light-emitting unit 20, wherein the first quantum well layer 302 is configured to emit light of the second wavelength λ2 under excitation of the light of the first wavelength λ1.

[0061] For example, in some embodiments of the present disclosure, the light of the first wavelength λ1 emitted by the LED light-emitting unit 20 includes light with a wavelength greater than or equal to 200 nm and less than or equal to 495 nm. For example, the LED light-emitting unit 20 may include a blue-emitting LED light-emitting unit, wherein the light of the first wavelength λ1 emitted by the blue-emitting LED light-emitting unit includes light with a wavelength greater than or equal to 395 nm and less than or equal to 495 nm; or, the LED light-emitting unit 20 may also include an ultraviolet-emitting LED light-emitting unit, wherein the light of the first wavelength λ1 emitted by the ultraviolet-emitting LED light-emitting unit includes light with a wavelength greater than or equal to 200 nm and less than or equal to 400 nm. By utilizing the light emitted by a small-sized, high-efficiency blue light LED light-emitting unit or an ultraviolet light-emitting unit to excite the first quantum well layer structure, light with a second wavelength can be obtained, for example, the second wavelength light includes red light with a wavelength greater than or equal to 620 nm and less than or equal to 760 nm, thereby obtaining a high-efficiency, small-sized red light LED light-emitting chip.

[0062] For example, in some embodiments of the present disclosure, continuing to refer to Figure 1, the LED light-emitting unit 20 includes: a first buffer layer 201 arranged on the side of the first bonding layer 301 away from the first quantum well layer 302; a second semiconductor layer 202 arranged on the side of the first buffer layer 201 away from the first quantum well layer 302; a second quantum well layer 203 arranged on the side of the second semiconductor layer 202 away from the first quantum well layer 302; a third semiconductor layer 204 arranged on the side of the second quantum well layer 203 away from the first quantum well layer 302; and a first electrode 205 arranged on the side of the third semiconductor layer 204 away from the first quantum well layer 302.

[0063] For example, in some embodiments of the present disclosure, with continued reference to FIG. 1 , the second semiconductor layer 202 may further include a second electrode connection portion 2021 that is not covered by the second quantum well layer 203 .

[0064] The LED light-emitting unit 20 also includes: a second electrode 206 arranged on the side of the second electrode connecting portion 2021 away from the first quantum well layer 302; and a first insulating layer 207 arranged on the side of both the first electrode 205 and the second electrode 206 away from the first quantum well layer 302, wherein the first insulating layer 207 includes a first via hole VH1 exposing at least a portion of the first electrode 205 and a second via hole VH2 exposing at least a portion of the second electrode 206.

[0065] The LED light emitting unit 20 further includes a first extraction electrode 208 and a second extraction electrode 209 , wherein the first extraction electrode 208 is electrically connected to the first electrode 205 through a first via hole VH1 ; the second extraction electrode 209 is electrically connected to the second electrode 206 through a second via hole VH2 .

[0066] By designing the first extraction electrode and the second extraction electrode, wherein the first extraction electrode and the second extraction electrode can be provided on the same layer, it is possible to facilitate the connection between the LED light emitting unit and the outside, for example, it is possible to facilitate the bonding between the LED light emitting unit and the light conversion unit 30 .

[0067] For example, in some embodiments of the present disclosure, the material of the first electrode 205 may include ITO. The thickness of the ITO may be 1 nm to 5000 nm. Preferably, the thickness of the ITO is 50 nm to 300 nm. By optimizing the material type and thickness of the first electrode, a first electrode with good transmittance and conductivity can be obtained. The first electrode material can also be annealed to improve the transmittance of the first electrode and the ohmic contact characteristics between the first electrode and the first lead-out electrode.

[0068] For example, the material of the second electrode 206 may include one of Ti and Cr; and / or the materials of the first extraction electrode 208 and the second extraction electrode 209 may include an alloy of one or more combinations of Ti, Al, Au, Sn, Ni, or Pt, or a stack of multiple combinations thereof. For example, the material of the second electrode 206 may be Ti, and the metal or alloy layer in contact with the second extraction electrode 209 may also include Ti, thereby enhancing the ohmic contact characteristics between the second electrode 206 and the second extraction electrode 209.

[0069] For example, the material of the second electrode 206 may be Cr, and the metal or alloy layer of the second extraction electrode 209 in contact with the second electrode 206 may also contain Cr, thereby enhancing the ohmic contact characteristics between the second electrode 206 and the second extraction electrode 209 .

[0070] FIG2 is a projection relationship diagram of a first quantum well layer and a second quantum well layer in a light-emitting chip according to some exemplary embodiments of the present disclosure.

[0071] For example, in some embodiments of the present disclosure, referring to FIG2 , the orthographic projection of the second quantum well layer 203 on the first bonding layer 301 falls within the orthographic projection of the first quantum well layer 302 on the first bonding layer 301. By designing the size of the first quantum well layer to be larger than the size of the LED light-emitting unit 20, side light leakage can be effectively reduced, and the conversion efficiency of converting light of the first wavelength into light of the second wavelength can be improved, thereby improving the luminous efficiency of the entire light-emitting chip.

[0072] For example, in some embodiments of the present disclosure, the material of the first semiconductor layer 303 may include AlGaInP; and / or the material of the first quantum well layer 302 may include an AlGaInP quantum well. For example, the first quantum well layer 302 may be formed by epitaxial growth on the first semiconductor layer 303. The first quantum well layer may include wells and barriers composed of AlGaInP / AlGaInP.

[0073] Exemplarily, the material of the first bonding layer 301 may include at least one of SiO2, benzocyclobutene, or SU8 negative photoresist. The first bonding layer is used to bond the light conversion unit 30 to the LED light-emitting unit 20. The material of the first bonding layer may include a permanent bonding adhesive, such as benzocyclobutene, SU8 negative photoresist, or other adhesive materials; the material of the first bonding layer may also include an inorganic dielectric material, such as SiO2.

[0074] For example, in some embodiments of the present disclosure, with continued reference to FIG1 , the first semiconductor layer 303 has a first thickness d1 in a direction perpendicular to the light-emitting surface, and the first thickness d1 is greater than or equal to 500 nm and less than or equal to 5 μm. By adjusting the thickness of the first semiconductor layer, the lattice mismatch between the first semiconductor layer 303 and the first quantum well layer 302 can be reduced.

[0075] Exemplarily, the first bonding layer 301 has a second thickness d2 in a direction perpendicular to the light emitting surface, and the second thickness d2 is greater than or equal to 10 nm and less than or equal to 5 um. Preferably, the range of the second thickness d2 is greater than or equal to 10 nm and less than or equal to 2.5 um. By adjusting the thickness of the first bonding layer, on the one hand, the bonding strength of the bonding layer can be guaranteed, and on the other hand, the side light leakage can be reduced. For example, in some embodiments, the material of the first bonding layer is benzocyclobutene, and 2.5 um thick benzocyclobutene is spin-coated on the first quantum well layer, and then maintained at 250°C, 5000 N pressure and 1 mBar vacuum conditions for 1 hour, so that the LED light-emitting unit 20 and the light conversion unit 30 can be bonded. By adjusting the material, thickness or process parameters of the first bonding layer, the blue light transmittance of the first bonding layer can be further improved. For example, a first bonding layer with a blue light transmittance greater than or equal to 95% can be obtained.

[0076] Exemplarily, the number of quantum well pairs in the first quantum well layer 302 is greater than or equal to 10. Preferably, the number of quantum well pairs in the first quantum well layer 302 is 20 to 40. By optimizing the number of quantum well pairs in the first quantum well layer, the light conversion efficiency of the light conversion unit can be further improved, thereby improving the light efficiency of the light-emitting chip.

[0077] FIG3A is a schematic structural diagram of a light-emitting chip according to some exemplary embodiments of the present disclosure; FIG3B is a schematic structural diagram of a light-reflecting layer in a light-emitting chip according to some exemplary embodiments of the present disclosure.

[0078] For example, in some embodiments of the present disclosure, referring to FIG3A , the light-emitting chip 100 may further include a reflective layer 40, which covers at least a portion of the side wall 210 of the LED light-emitting unit 20, wherein the reflective layer 40 includes a first reflective sub-layer 401, a second reflective sub-layer 402, and a third reflective sub-layer 403; the side wall 210 of the LED light-emitting unit includes a first side wall 211, a second side wall 212, and a third side wall 213. For example, the first photoreflective sublayer 401 covers at least a portion of the first side wall 211; the second photoreflective sublayer 402 covers at least a portion of the second side wall 212; and the third photoreflective sublayer 403 covers at least a portion of the third side wall 213, wherein the first side wall 211 includes the side wall of the side wall 210 of the LED light-emitting unit that is close to the first lead-out electrode 208 and away from the second lead-out electrode 209; the second side wall 212 includes the side wall of the side wall 210 of the LED light-emitting unit that is located between the first lead-out electrode 208 and the second lead-out electrode 209; and the third side wall 213 includes the side wall of the side wall 210 of the LED light-emitting unit that is close to the second lead-out electrode 209 and away from the first lead-out electrode 208.

[0079] By adding a reflective layer on the side of the LED light-emitting unit, light can be effectively prevented from leaking from the side, thereby improving the light output efficiency of the light output surface.

[0080] 3B , in some embodiments of the present disclosure, the light-reflecting layer 40 includes a first passivation layer 410, a first metal light-reflecting layer 420, and a second passivation layer 430. For example, the material of the first metal light-reflecting layer may include one of Al or Ag, and the materials of the first passivation layer and the second passivation layer may include silicon oxide or silicon nitride, to prevent the first metal light-reflecting layer from causing electrical defects in the light-emitting chip.

[0081] FIG4 is a schematic structural diagram of a light-emitting chip according to some exemplary embodiments of the present disclosure.

[0082] For example, in some embodiments of the present disclosure, referring to FIG. 4 , the light-emitting chip 100 further includes a first inorganic reflective layer 304 disposed between the first semiconductor layer 303 and the first quantum well layer 302. For example, the first inorganic reflective layer 304 may include a stack of GaAs and AlAs layers. By adding the first inorganic reflective layer and utilizing Bragg reflection of the first inorganic reflective layer, at least a portion of the photoinduced blue light in the underlying layer can be reflected. This can optimize the chromaticity of the light emitted by the light-emitting chip. Furthermore, some of the reflected blue light can continue to excite the first quantum well layer to generate light of a second wavelength, such as red light, thereby improving the light efficiency of the light-emitting chip and thereby enhancing the performance of the light-emitting chip.

[0083] FIG5 is a schematic structural diagram of a sub-millimeter diode light-emitting chip according to some exemplary embodiments of the present disclosure.

[0084] For example, in some embodiments of the present disclosure, a sub-millimeter diode light-emitting chip 500 is provided. Referring to FIG5 , the sub-millimeter diode light-emitting chip 500 may include: a second substrate 501; a second bonding layer 502 disposed on the second substrate 501; and a light-emitting chip 100 disposed on a side of the second bonding layer 502 away from the second substrate 501. The light-emitting chip 100 may include any of the aforementioned embodiments. The second substrate 501 is located on the light-emitting side of the light-emitting chip 100.

[0085] After the light-emitting chip 100 is prepared, the size of the light-emitting chip can be reduced by further processes such as substrate transfer, chip cutting and splitting to obtain a plurality of independent small-sized sub-millimeter diode (mini LED) light-emitting chips. For example, the light-emitting chip is transferred to a glass substrate or a sapphire substrate, and then the substrate is thinned. The thickness of the substrate can be adjusted according to the size of the chip. The size of the sub-millimeter diode (mini LED) light-emitting chip is between 50 and 400 microns. Preferably, the size of the sub-millimeter diode (mini LED) light-emitting chip is between 80 and 300 microns. After completing the substrate transfer and the light-emitting chip cutting, the substrate can be further split, for example, by using laser invisible cutting technology to scratch the glass substrate or sapphire substrate, and then using a splitter to split it, so that independent small-sized sub-millimeter diode (mini LED) light-emitting chips can be obtained.

[0086] FIG6 is a schematic structural diagram of a light-emitting chip array according to some exemplary embodiments of the present disclosure.

[0087] For example, in some embodiments of the present disclosure, a light-emitting chip array 600 is provided. The light-emitting chip array 600 may include: a first substrate 601; a third bonding layer 602 arranged on the first substrate 601; and a plurality of light-emitting chips 100 arranged in an array on the side of the third bonding layer 602 away from the first substrate 601. The light-emitting chip 100 may include a light-emitting chip as described in any of the aforementioned embodiments. For example, after obtaining the light-emitting chip 100, the light-emitting chip may be patterned, for example, the LED light-emitting unit 20 and the light conversion unit 30 may be patterned separately, thereby obtaining a small-sized light-emitting chip array. By controlling the patterning parameters, light-emitting chip arrays of different sizes can be obtained. For example, a micro light-emitting diode (i.e., Micro LED) light-emitting chip array with a size of less than 100 microns can be obtained.

[0088] FIG7 is a flow chart of a method for preparing a light-emitting chip according to some exemplary embodiments of the present disclosure; and FIG8 to FIG20 are schematic diagrams of partial structures of the light-emitting chip at different stages of the preparation process of FIG7 .

[0089] Illustratively, in some embodiments of the present disclosure, a method for manufacturing a light-emitting chip 100 is provided. Illustratively, the method for manufacturing the light-emitting chip 100 includes steps S01 to S13.

[0090] In step S01 , referring to FIG. 8 , a first buffer material layer 21 , a second semiconductor material layer 22 , a second quantum well material layer 23 and a third semiconductor material layer 24 are sequentially deposited on a first wafer 1 to form an LED epitaxial layer 200 .

[0091] In step S02 , referring to FIG. 9 , a first electrode material layer 25 is formed on a side of the LED epitaxial layer 200 away from the first wafer 1 .

[0092] In step S03 , referring to FIG. 10 , a patterning process is performed on the LED epitaxial layer 200 and the first electrode material layer 25 to form a mesa 221 on the second semiconductor material layer 22 that is not covered by the second quantum well material layer 23 .

[0093] In step S04 , referring to FIG. 11 , a second electrode material layer 26 is formed on a side of the mesa 221 of the second semiconductor material layer 22 that is not covered by the second quantum well material layer 23 and is away from the first wafer 1 .

[0094] In step S05, referring to Figure 12, a first insulating material layer 27 is formed on the side of the first electrode material layer 25 and the second electrode material layer 26 away from the first chip 1, and a composition process is performed on the first insulating material layer 27 to form a first via hole VH1 exposing a portion of the first electrode material layer 25 and a second via hole VH2 exposing a portion of the second electrode material layer 26.

[0095] In step S06, referring to Figure 13, a metal conductive material layer 28 is formed on the side of the first insulating material layer 27 away from the first chip 1, and a composition process is performed on the metal conductive material layer 28 to form a first lead-out electrode 208 electrically connected to the first electrode material layer through the first via hole VH1 and a second lead-out electrode 209 electrically connected to the second electrode material layer through the second via hole VH2, so as to form an LED light-emitting unit 20 located on the first chip 1.

[0096] In step S07, referring to FIG14 , a patterning process is performed on the LED light-emitting units 20 to form a plurality of LED light-emitting units 20 on the first wafer 1. For example, the side portions of the LED light-emitting units may be deeply etched to ensure that the GaN in the cutting lanes is cleanly etched, thereby facilitating subsequent cutting of the LED light-emitting units.

[0097] In step S08, referring to FIG15 , a third bonding material layer 62 is formed on the side of the metal conductive material layer 28 away from the first wafer 1. For example, in some embodiments, the third bonding material layer can be a temporary bonding adhesive to facilitate substrate transfer of the LED light-emitting chip in subsequent processes. The temporary bonding adhesive can be a pyrolysis temporary bonding adhesive, a laser decomposition temporary bonding adhesive, a mechanical decomposition temporary bonding adhesive, or a chemical decomposition temporary bonding adhesive. In other embodiments, the third bonding material layer can also be a permanent bonding adhesive.

[0098] In step S09, referring to FIG16 , a first substrate 601 is formed on the side of the third bonding material layer 62 away from the first wafer 1. In some embodiments, the first substrate may include a temporary substrate to facilitate substrate transfer of the LED light-emitting chip in subsequent processes. The temporary substrate may include sapphire, glass, quartz, or a silicon wafer. In other embodiments, the first substrate may also include a permanent substrate, serving as a support substrate for a light-emitting chip array, such as a micro LED light-emitting chip array.

[0099] In step S10, referring to FIG17 , the first wafer 1 is removed to form a plurality of LED light-emitting units 20 on the first substrate 601. For example, if the first wafer is sapphire-based, laser lift-off can be used; if the first wafer is silicon-based, mechanical thinning and dry or wet etching can be used to remove the silicon-based substrate.

[0100] In step S11 , referring to FIG. 18 , a second buffer material layer 34 , a first semiconductor material layer 33 and a first quantum well material layer 32 are sequentially deposited on the second wafer 2 to form a light conversion unit 30 on the second wafer 2 .

[0101] In step S12 , referring to FIG. 19 , a first bonding material layer 31 is formed between the first buffer material layer 21 and the first quantum well material layer 32 to achieve bonding between the plurality of LED light emitting units 20 and the light conversion unit 30 .

[0102] In step S13 , referring to FIG. 20 , the second wafer 2 and the second buffer material layer 34 are removed to form the light emitting chip 100 on the first substrate 601 .

[0103] FIG21 is a flow chart of a method for preparing a sub-millimeter diode light-emitting chip according to some exemplary embodiments of the present disclosure; FIG22 to FIG25 are schematic diagrams of the partial structures of the sub-millimeter diode light-emitting chip at different stages of the preparation process of FIG21 .

[0104] For example, in some embodiments of the present disclosure, after the light-emitting chip 100 is formed on the first substrate 601 , further processing may be performed to obtain a sub-millimeter diode light-emitting chip.

[0105] Specifically, the method may further include: in step S07 of preparing the light-emitting chip 100 located on the first substrate 601, adjusting the parameters of the composition process, performing the composition process on the LED light-emitting unit 20, and forming a plurality of sub-millimeter diode light-emitting units located on the first chip 1; and after forming the light-emitting chip 100 located on the first substrate 601, continuing to perform the following steps S14 to S17, wherein the light-emitting chip 100 includes a plurality of sub-millimeter diode light-emitting units.

[0106] In step S14 , referring to FIG. 22 , a second bonding material layer 52 is formed on a side of the first semiconductor layer 303 away from the first substrate 601 .

[0107] In step S15 , referring to FIG. 23 , a second substrate 501 is formed on a side of the second bonding material layer 52 away from the first substrate 601 .

[0108] For example, in some embodiments, forming the second bonding material layer and the second substrate on the first semiconductor layer may be completed in the same process step or in different process steps.

[0109] In step S16 , referring to FIG. 24 , the first substrate 601 and the third bonding material layer 62 are removed.

[0110] In step S17, referring to FIG. 25 , a patterning process is performed on the second substrate 501, the second bonding material layer 52, the first semiconductor material layer 33, the first quantum well material layer 32, and the first bonding material layer 31 to form a plurality of independent sub-millimeter diode light-emitting chips 500. In some embodiments, before patterning the second substrate, the second substrate may be thinned to facilitate subsequent patterning.

[0111] FIG26 is a schematic structural diagram of a light-emitting chip array according to some exemplary embodiments of the present disclosure.

[0112] For example, in some embodiments of the present disclosure, referring to FIG. 26 , after the light emitting chip 100 is formed on the first substrate 601 , further processing may be performed to obtain a light emitting chip array 600 .

[0113] For example, a patterning process may be performed on the first semiconductor material layer 33 , the first quantum well material layer 32 and the first bonding material layer 31 to form a light-emitting chip array on the first substrate 601 .

[0114] In some embodiments, a micro light emitting diode (micro LED) light emitting chip array can be obtained by adjusting the size of the light emitting chips in the light emitting chip array, for example, controlling the size of the light emitting chips to be less than 100 microns.

[0115] By combining the light conversion unit with the LED light-emitting unit and using high-efficiency blue light LEDs or ultraviolet light LEDs to excite the light conversion unit, light of other colors can be formed. This makes it possible to achieve high-efficiency light output of multiple colors while miniaturizing the LED. For example, a high-efficiency red mini LED light-emitting chip can be formed, and a high-efficiency red micro LED light-emitting chip array can also be formed, which is conducive to expanding the application scenarios of LED light-emitting chips.

[0116] With the development of LED miniaturization technology, LED light-emitting chips are widely used in display products, such as mini LED display devices and micro LED display devices, wherein the display substrate of the display device includes a large number of LED light-emitting chips. When using LED light-emitting chips to prepare a display substrate, the LED light-emitting chip is usually used as a light-emitting unit in a pixel. A colored display substrate usually requires pixel units of multiple colors, for example, a pixel unit that displays red, a pixel unit that displays green, and a pixel unit that displays blue. However, when LED light-emitting chips are used as light-emitting units of a display substrate, since the efficiency of LEDs of different colors decays differently during the miniaturization process, it is easy to cause uneven brightness and color deviation of the display screen, affecting the display quality. Especially in micro LED display substrates, the red micro LED light-emitting chips and green micro LED light-emitting chips have a significant decrease in brightness due to the decrease in efficiency at low currents, resulting in obvious color deviation in the display screen, which seriously affects the display effect of the display substrate.

[0117] For example, in some embodiments of the present disclosure, a high-resolution monochrome micro LED array can be combined with light color conversion technology to display a high-resolution color display substrate. The high-resolution monochrome micro LED array can include a blue micro LED array or an ultraviolet micro LED array.

[0118] For example, the wavelength range of the light emitted by the blue micro LED may include 430nm to 480nm. Preferably, the wavelength range of the light emitted by the blue micro LED may include 450nm to 465nm. The wavelength of the light emitted by the ultraviolet micro LED is less than or equal to 400nm.

[0119] High-resolution, single-color micro LED arrays can be fabricated by bonding the entire epitaxial layer and then patterning it to form a micro LED array. Alternatively, LED chips can be patterned to form multiple micro LED chips, which are then aligned and bonded to form the micro LED array. For example, the spacing between adjacent chips in a single-color micro LED array is 50 μm or less, and preferably 10 μm or less.

[0120] 27 is a schematic plan view of a display substrate according to some exemplary embodiments of the present disclosure; and FIG. 28 is a schematic partial interface view taken along line AA′ in the display substrate of FIG. 27 according to some exemplary embodiments of the present disclosure.

[0121] For example, in some embodiments of the present disclosure, a display substrate 700 is provided. Referring to FIG. 27 and FIG. 28 , the display substrate 700 includes: a base substrate 701; and a plurality of pixel units PX disposed on the base substrate 701. The plurality of pixel units PX are arranged in an array along a first direction D1 and a second direction D2, wherein the first direction D1 and the second direction D2 intersect. At least one pixel unit PX includes a plurality of sub-pixels SP, for example, a first sub-pixel SP1, a second sub-pixel SP2, and a third sub-pixel SP3. The first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3 each include an LED light-emitting unit 20 and a light guide layer 702. The LED light-emitting unit 20 is configured to emit light of a first wavelength, and the light-guiding layer 702 may include a second light conversion layer 7022 arranged on the light-emitting side of the LED light-emitting unit 2002 of the second sub-pixel SP2, and the second light conversion layer 7022 is configured to convert the light of the first wavelength λ1 into light of a second wavelength λ, wherein the orthographic projection of the LED light-emitting unit 2002 of the second sub-pixel SP2 on the base substrate 701 falls within the orthographic projection of the second light conversion layer 7022 on the base substrate 701.

[0122] The light-guiding layer 702 may further include a third light conversion layer 7023 disposed on the light-emitting side of the LED light-emitting unit 2003 of the third sub-pixel SP3. The third light conversion layer 7023 is configured to convert light of the first wavelength λ into light of a third wavelength λ, wherein the orthographic projection of the LED light-emitting unit 2003 of the third sub-pixel SP3 on the substrate 701 falls within the orthographic projection of the third light conversion layer 7023 on the substrate 701. The light of the first wavelength λ, the second wavelength λ, and the third wavelength λ have different colors. For example, the light of the first wavelength λ may include blue light or ultraviolet light, the light of the second wavelength λ may include red light, and the light of the third wavelength λ may include green light. By designing the second and third light conversion layers, a sub-pixel unit that can emit multiple colors can be implemented using a single type of LED light-emitting unit, thereby achieving a color display.

[0123] 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.

[0124] 28 , the LED light-emitting unit may include a blue-emitting LED light-emitting unit. The material of the second light conversion layer 7022 may include red quantum dots; and / or the material of the third light conversion layer 7023 may include green quantum dots.

[0125] By combining blue LEDs with red and green quantum dots, a single blue LED light-emitting unit can be used to form sub-pixels encompassing red, green, and blue, thus achieving a color display. This light-color conversion approach can streamline the process flow and reduce manufacturing complexity. Furthermore, by leveraging the minimal efficiency drop during the miniaturization of blue LED chips and the more consistent variation across a single type of LED chip, color shift on the display substrate can be reduced, brightness uniformity can be improved, and the display quality can be enhanced.

[0126] For example, in some embodiments of the present disclosure, with continued reference to FIG. 28 , when the LED light-emitting unit is a blue-light-emitting LED light-emitting unit, the light-guiding layer 702 may further include a first light-guiding layer 7021 disposed on the light-emitting side of the LED light-emitting unit 2001 of the first sub-pixel SP1, wherein the orthographic projection of the LED light-emitting unit 2001 of the first sub-pixel SP1 on the substrate 701 falls within the orthographic projection of the first light-guiding layer 7021 on the substrate 701. The material of the first light-guiding layer 7021 includes scattering particles. By disposing scattering particles above the blue-light-emitting unit, the light-emitting intensity and angle of the blue light emitted by the first sub-pixel SP1 can be adjusted, further improving the display quality of the display substrate.

[0127] For example, in some embodiments of the present disclosure, with continued reference to FIG. 28 , the display substrate 700 may further include a second dielectric layer 703 located on a side of the light guide layer 702 away from the base substrate 701. The second dielectric layer 703 includes a main portion 7031 and a spacer portion 7032, wherein the spacer portion 7032 is located in the gap between the light guide layers 702 of adjacent sub-pixels SP. When the LED light-emitting unit 20 is a blue-emitting LED chip, the orthographic projection of the second dielectric layer 703 on the base substrate 701 does not overlap with the orthographic projection of the LED light-emitting unit 2001 of the first sub-pixel SP1 on the base substrate 701. Furthermore, the orthographic projections of each of the LED light-emitting unit 2002 of the second sub-pixel SP2 and the LED light-emitting unit 2003 of the third sub-pixel SP3 on the base substrate 701 fall within the orthographic projection of the main portion 7031 of the second dielectric layer 703 on the base substrate 701. For example, the second dielectric layer 703 may include a stacked structure of SiO2 layers and TiO2 layers; or, the second dielectric layer may include a stacked structure of SiO2 layers and NbO2 layers; and / or, the second dielectric layer has a third thickness d3 in a direction perpendicular to the substrate, wherein the third thickness d3 is less than or equal to 5 μm, preferably, less than or equal to 3 μm. By adjusting process parameters such as the film material type and thickness of the second dielectric layer, multiple inorganic films can be used to selectively reflect and transmit light of different wavelengths, such that the second dielectric layer can reflect blue light and transmit red and green light, thereby improving the light extraction efficiency of the second and third sub-pixels.

[0128] FIG. 29 is a partial schematic diagram of an interface taken along line AA′ in the display substrate of FIG. 27 according to some other exemplary embodiments of the present disclosure.

[0129] For example, in some embodiments of the present disclosure, referring to FIG. 29 , when the LED light-emitting unit is an ultraviolet-emitting LED light-emitting unit, the light-guiding layer 702 may further include a first light conversion layer 7024 disposed on the light-emitting side of the LED light-emitting unit 2001 of the first sub-pixel SP1. The first light conversion layer 7024 is configured to convert light of the first wavelength λ1 into light of a fourth wavelength λ, wherein the first wavelength λ and the fourth wavelength λ have different colors. For example, the first wavelength is ultraviolet light, and the fourth wavelength is blue light.

[0130] For example, the material of the first light conversion layer 7024 may include blue quantum dots; and the orthographic projection of the LED light-emitting unit 2001 of the first sub-pixel SP1 on the substrate 701 falls within the orthographic projection of the first light conversion layer 7024 on the substrate 701. By respectively arranging blue quantum dots, red quantum dots, and green quantum dots above multiple ultraviolet LED light-emitting units, a single ultraviolet LED light-emitting unit can be used to form sub-pixels including red, green, and blue colors, thereby achieving a color display. By utilizing a light color conversion solution, the process flow can be simplified and the process difficulty can be reduced. At the same time, the characteristics of the miniaturization process of ultraviolet LED light-emitting chips, such as small efficiency drop and more consistent variation range of a single type of LED light-emitting chip, can be utilized to reduce the color cast of the display substrate and improve the uniformity of pixel brightness, thereby improving the display effect.

[0131] For example, in some embodiments of the present disclosure, with continued reference to FIG. 29 , the display substrate 700 further includes a second dielectric layer 703 located on a side of the light guide layer 702 away from the base substrate 701. The second dielectric layer 703 includes a main portion 7031 and a spacer portion 7032. The spacer portion 7032 is located in the gap between the light guide layer 702 of adjacent sub-pixels SP. The orthographic projection of each of the LED light-emitting unit 2001 of the first sub-pixel SP1, the LED light-emitting unit 2002 of the second sub-pixel SP2, and the LED light-emitting unit 2003 of the third sub-pixel SP3 onto the base substrate 701 falls within the orthographic projection of the main portion 7031 of the second dielectric layer 703 onto the base substrate 701. The second dielectric layer 703 may include a stacked structure of SiO2 and TiO2 layers; or a stacked structure of SiO2 and NbO2 layers; and / or the second dielectric layer has a third thickness d3 perpendicular to the base substrate, wherein the third thickness d3 is less than or equal to 5 μm, preferably less than or equal to 3 μm. By adjusting process parameters such as the film material type and thickness of the second dielectric layer, multiple inorganic film layers can be used to selectively reflect and transmit light of different wavelengths, so that the second dielectric layer can reflect ultraviolet light and transmit blue, red, and green light, thereby improving the light extraction efficiency of the first sub-pixel SP1, the second sub-pixel SP2, and the third sub-pixel SP3.

[0132] For example, in some embodiments of the present disclosure, with reference to Figures 28 and 29, the display substrate 700 further includes a black glue layer 704 disposed on the side of the second dielectric layer 703 away from the base substrate 701, wherein the black glue layer 704 is located between adjacent sub-pixels SP and is used to reflect at least a portion of the light emitted by the sub-pixel to the adjacent sub-pixel side. For example, a film pressing process can be used to press a black glue film onto the sub-pixel, and the thickness of the black glue layer in the black glue film is less than 20um, preferably, the thickness of the black glue layer is less than 5um. The black glue film is cured by thermal curing or UV curing glue. Then, a chemical mechanical polishing technique or a dry etching method can be used to remove part of the black glue above the pixel, retaining the black glue in the sub-pixel gap. By setting a retaining wall structure with a high aspect ratio, the problem of light crosstalk between different sub-pixels can be solved.

[0133] 30 is a schematic diagram of a partial interface taken along line AA′ in the display substrate of FIG. 27 according to some other exemplary embodiments of the present disclosure; FIG. 31 is a schematic diagram of a partial interface taken along line AA′ in the display substrate of FIG. 27 according to some other exemplary embodiments of the present disclosure.

[0134] For example, in some embodiments of the present disclosure, with reference to FIG30 and FIG31 , the display substrate 700 may further include a first dielectric layer 705 disposed between the LED light-emitting unit 20 and the light guide layer 702. The first dielectric layer may include a stacked structure of SiO2 layers and TiO2 layers; or, the first dielectric layer may include a stacked structure of SiO2 layers and NbO2 layers; and / or, the first dielectric layer may have a fourth thickness d4 in a direction perpendicular to the base substrate 701, and the fourth thickness d4 may be less than or equal to 5 μm.

[0135] By adjusting the process parameters such as the type and thickness of the film material of the first dielectric layer, a multilayer inorganic film layer can be used to form selective reflection and transmission of light of different wavelength bands, so that the first dielectric layer can selectively reflect and transmit the light emitted by the LED light-emitting unit in the lower layer. For example, referring to Figure 30, when the light emitted by the LED light-emitting unit in the lower layer is blue light, the first dielectric layer can be designed to transmit blue light and return red and green light. Referring to Figure 31, when the light emitted by the LED light-emitting unit in the lower layer is ultraviolet light, the first dielectric layer can be designed to transmit ultraviolet light and return blue, red and green light. By adding a first dielectric layer between the LED light-emitting unit and the light-guiding layer, and using the first dielectric layer to selectively reflect and transmit the light emitted by the LED light-emitting unit, the chromaticity of the light emitted by the pixel unit can be further optimized, and the display effect of the display substrate can be improved.

[0136] FIG32 is a schematic structural diagram of a display device according to some exemplary embodiments of the present disclosure.

[0137] Optionally, embodiments of the present disclosure further provide a display device. Referring to FIG. 32 , the display device 1000 may include the display substrate 700 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 substrates provided in the aforementioned embodiments.

[0138] FIG33 is a flow chart of manufacturing a display substrate according to some exemplary embodiments of the present disclosure; and FIG34 to FIG38 are schematic diagrams of partial structures of the display substrate at different stages in the manufacturing process of FIG33 .

[0139] Illustratively, in some embodiments of the present disclosure, the method for preparing a display substrate includes steps S101 to S105.

[0140] In step S101 , referring to FIG. 34 , a plurality of LED light emitting units 20 are formed on a base substrate 701 .

[0141] In step S102 , referring to FIG. 35 , a first dielectric material layer 73 is formed on a side of the plurality of LED light-emitting units 20 away from the base substrate 701 .

[0142] In step S103, referring to FIG36 , different light-guiding material layers are deposited in multiple steps on the side of the first dielectric material layer 75 away from the base substrate 701 and patterned to form light-guiding material layers 72 corresponding to different LED light-emitting units. For example, a first light-guiding material layer 721 can be deposited and patterned to form a first light-guiding film covering the LED light-emitting unit 2001; a second light-conversion material layer 722 can be deposited and patterned to form a second light-conversion layer covering the LED light-emitting unit 2002; and a third light-conversion material layer 723 can be deposited and patterned to form a third light-conversion layer covering the LED light-emitting unit 2003.

[0143] In step S104 , referring to FIG. 37 , a second dielectric layer 73 is formed on a side of the light guide material layer 72 away from the base substrate 701 , and a patterning process is performed.

[0144] For example, in some embodiments of the present disclosure, when the LED light-emitting unit emits blue light, when performing a patterning process on the second dielectric layer, an opening process can be performed above the blue sub-pixel. For example, a yellow light process can be used as a mask, and dry etching can be used for patterning.

[0145] For example, when the LED light-emitting unit emits ultraviolet light, the patterning step can be omitted when performing the patterning process on the second dielectric layer.

[0146] In step S105 , referring to FIG. 38 , a black glue layer 704 is formed on a side of the second dielectric material layer 73 away from the base substrate 701 , and a patterning process is performed to form a display substrate.

[0147] 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 light-emitting chip, characterized in that, the light-emitting chip comprises: an LED light-emitting unit configured to emit light of a first wavelength; and a light conversion unit disposed on the light-emitting side of the LED light-emitting unit, the light conversion unit being configured to convert the light of the first wavelength into light of a second wavelength, wherein the color of the light of the first wavelength is different from that of the light of the second wavelength, the light conversion unit comprises: a first bonding layer disposed on the light-emitting side of the LED light-emitting unit; a first quantum well layer disposed on a side of the first bonding layer away from the LED light-emitting unit; and a first semiconductor layer disposed on a side of the first quantum well layer away from the LED light-emitting unit, wherein the first quantum well layer is configured to emit the light of the second wavelength under excitation by the light of the first wavelength.

2. The light-emitting chip according to claim 1, wherein, the LED light-emitting unit comprises: a first buffer layer disposed on a side of the first bonding layer away from the first quantum well layer; a second semiconductor layer disposed on a side of the first buffer layer away from the first quantum well layer; a second quantum well layer disposed on a side of the second semiconductor layer away from the first quantum well layer; a third semiconductor layer disposed on a side of the second quantum well layer away from the first quantum well layer; and a first electrode disposed on a side of the third semiconductor layer away from the first quantum well layer.

3. The light-emitting chip according to claim 2, wherein, the second semiconductor layer comprises a second electrode connection portion not covered by the second quantum well layer; the LED light-emitting unit further comprises: a second electrode disposed on a side of the second electrode connection portion away from the first quantum well layer; and a first insulating layer disposed on a side of both the first electrode and the second electrode away from the first quantum well layer, wherein the first insulating layer comprises a first via exposing at least a part of the first electrode and a second via exposing at least a part of the second electrode; and the LED light-emitting unit further comprises: a first lead-out electrode and a second lead-out electrode, wherein the first lead-out electrode is electrically connected to the first electrode through the first via; and the second lead-out electrode is electrically connected to the second electrode through the second via.

4. The light-emitting chip according to claim 2 or 3, wherein, a positive projection of the second quantum well layer on the first bonding layer falls within a positive projection of the first quantum well layer on the first bonding layer.

5. The light-emitting chip according to any one of claims 1-4, wherein, the thickness of the first semiconductor layer is greater than or equal to 500 nm and less than or equal to 5 μm; and / or, the number of quantum well pairs in the first quantum well layer is greater than or equal to 10; and / or, the thickness of the first bonding layer is greater than or equal to 10 nm and less than or equal to 5 μm.

6. The light-emitting chip according to any one of claims 1-5, wherein, the material of the first semiconductor layer comprises AlGaInP; and / or, the material of the first quantum well layer comprises an AlGaInP quantum well; and / or, The material of the first bonding layer includes SiO 2 , at least one of benzocyclobutene or SU8 negative photoresist.

7. The light-emitting chip according to any one of claims 1-6, wherein, the light with the first wavelength emitted by the LED light-emitting unit includes light with a wavelength greater than or equal to 200 nm and less than or equal to 495 nm; and / or, the light with the second wavelength includes light with a wavelength greater than or equal to 620 nm and less than or equal to 760 nm.

8. The light-emitting chip according to any one of claims 1-7, wherein, the light-emitting chip further includes a reflective layer, and the reflective layer covers at least a part of the sidewall of the LED light-emitting unit, wherein, the reflective layer includes a first anti-photon layer, a second anti-photon layer, and a third anti-photon layer; the sidewalls of the LED light-emitting unit include a first sidewall, a second sidewall, and a third sidewall; the first anti-photon layer covers at least a part of the first sidewall; the second anti-photon layer covers at least a part of the second sidewall; and the third anti-photon layer covers at least a part of the third sidewall, wherein, the first sidewall includes the sidewall of the LED light-emitting unit that is close to the first lead electrode and far from the second lead electrode; the second sidewall includes the sidewall of the LED light-emitting unit that is located between the first lead electrode and the second lead electrode; the third sidewall includes the sidewall of the LED light-emitting unit that is close to the second lead electrode and far from the first lead electrode.

9. The light-emitting chip according to claim 8, wherein, the reflective layer includes a first passivation layer, a first metal reflective layer, and a second passivation layer.

10. The light-emitting chip according to any one of claims 1-9, wherein, the light-emitting chip further includes a first inorganic reflective layer disposed between the first semiconductor layer and the first quantum well layer, the first inorganic reflective layer includes a stack of a GaAs layer and an AlAs layer combination.

11. The light-emitting chip according to any one of claims 2-4, wherein, the material of the first electrode includes ITO; and / or, the material of the second electrode includes one of Ti or Cr; and / or, the first lead electrode and the second lead electrode are located on the same layer, wherein the materials of the first lead electrode and the second lead electrode include an alloy of one or more combinations of Ti, Al, Au, Sn, Ni, or Pt or a stack of multiple combinations.

12. A submillimeter diode light-emitting chip, characterized in that, the submillimeter diode light-emitting chip includes: a second substrate; a second bonding layer disposed on the second substrate; and a light-emitting chip disposed on the side of the second bonding layer away from the second substrate, wherein, the light-emitting chip includes the light-emitting chip according to any one of claims 1-11, wherein, the second substrate is located on the light-emitting side of the light-emitting chip.

13. A light-emitting chip array, characterized in that, the light-emitting chip array includes: a first substrate; a third bonding layer disposed on the first substrate; and a plurality of light-emitting chips arranged in an array on the side of the third bonding layer away from the first substrate, Among them, the light-emitting chip includes the light-emitting chip described in any one of claims 1 to 11.

14. A method for manufacturing a light-emitting chip, characterized in that, the method includes: sequentially depositing a first buffer material layer, a second semiconductor material layer, a second quantum well material layer, and a third semiconductor material layer on a first wafer to form an LED epitaxial layer; forming a first electrode material layer on a side of the LED epitaxial layer away from the first wafer; performing a patterning process on the LED epitaxial layer and the first electrode material layer to form a mesa on the second semiconductor material layer that is not covered by the second quantum well material layer; forming a second electrode material layer on a side of the mesa of the second semiconductor material layer that is not covered by the second quantum well material layer and away from the first wafer; forming a first insulating material layer on a side of the first electrode material layer and the second electrode material layer away from the first wafer, and performing a patterning process on the first insulating material layer to form a first via exposing a part of the first electrode material layer and a second via exposing a part of the second electrode material layer; forming a metal conductive material layer on a side of the first insulating material layer away from the first wafer, and performing a patterning process on the metal conductive material layer to form a first lead electrode electrically connected to the first electrode material layer through the first via and a second lead electrode electrically connected to the second electrode material layer through the second via, so as to form an LED light-emitting unit located on the first wafer; performing a patterning process on the LED light-emitting unit to form a plurality of LED light-emitting units located on the first wafer; forming a third bonding material layer on a side of the metal conductive material layer away from the first wafer; forming a first substrate on a side of the third bonding material layer away from the first wafer; removing the first wafer to form a plurality of LED light-emitting units located on the first substrate; and sequentially depositing a second buffer material layer, a first semiconductor material layer, and a first quantum well material layer on a second wafer to form a light conversion unit located on the second wafer; forming a first bonding material layer between the first buffer material layer and the first quantum well material layer to realize bonding of the plurality of LED light-emitting units and the light conversion unit; and removing the second wafer and the second buffer material layer to form a light-emitting chip located on the first substrate.

15. The manufacturing method according to claim 14, wherein, the performing a patterning process on the LED light-emitting unit to form a plurality of LED light-emitting units located on the first wafer includes: performing a patterning process on the LED light-emitting unit to form a plurality of sub-millimeter diode light-emitting units located on the first wafer; the method further includes: forming a second bonding material layer on a side of the first semiconductor layer away from the first substrate; forming a second substrate on a side of the second bonding material layer away from the first substrate; removing the first substrate and the third bonding material layer; A patterning process is performed on the second substrate, the second bonding material layer, the first semiconductor material layer, the first quantum well material layer, and the first bonding material layer to form a plurality of independent submillimeter diode light-emitting chips.

16. The manufacturing method according to claim 14 or 15, wherein, The performing a patterning process on the LED light-emitting unit to form a plurality of LED light-emitting units located on the first wafer includes: Performing a patterning process on the LED light-emitting unit to form a plurality of micro diode light-emitting units located on the first wafer; The method further includes: Performing a patterning process on the first semiconductor material layer, the first quantum well material layer, and the first bonding material layer to form a plurality of micro diode light-emitting chip arrays located on the first substrate.

17. A display substrate, characterized in that, The display substrate includes: A substrate; and A plurality of pixel units provided on the substrate, at least one pixel unit including a first sub-pixel, a second sub-pixel, and a third sub-pixel, wherein the first sub-pixel, the second sub-pixel, and the third sub-pixel respectively include an LED light-emitting unit and a light guide layer, and the LED light-emitting unit is configured to emit light of a first wavelength, The light guide layer includes a second light conversion layer provided on the light-emitting side of the LED light-emitting unit of the second sub-pixel, and the second light conversion layer is configured to convert the light of the first wavelength into light of a second wavelength, wherein the orthographic projection of the LED light-emitting unit of the second sub-pixel on the substrate falls within the orthographic projection of the second light conversion layer on the substrate; The light guide layer further includes a third light conversion layer provided on the light-emitting side of the LED light-emitting unit of the third sub-pixel, and the third light conversion layer is configured to convert the light of the first wavelength into light of a third wavelength, wherein the orthographic projection of the LED light-emitting unit of the third sub-pixel on the substrate falls within the orthographic projection of the third light conversion layer on the substrate, wherein the colors of the light of the first wavelength, the second wavelength, and the third wavelength are different.

18. The display substrate according to claim 17, wherein, The material of the second light conversion layer includes red quantum dots; and / or, The material of the third light conversion layer includes green quantum dots.

19. The display substrate according to claim 18, wherein, The light guide layer further includes a first light guide layer provided on the light-emitting side of the LED light-emitting unit of the first sub-pixel, wherein the orthographic projection of the LED light-emitting unit of the first sub-pixel on the substrate falls within the orthographic projection of the first light guide layer on the substrate; and The material of the first light guide layer includes scattering particles.

20. The display substrate according to claim 18, wherein, The light guide layer further includes a first light conversion layer provided on the light-emitting side of the LED light-emitting unit of the first sub-pixel, and the first light conversion layer is configured to convert the light of the first wavelength into light of a fourth wavelength, wherein the colors of the light of the first wavelength and the fourth wavelength are different, Wherein, the material of the first light conversion layer includes blue quantum dots; and The orthographic projection of the LED light-emitting unit of the first sub-pixel on the substrate falls within the orthographic projection of the first light conversion layer on the substrate.

21. The display substrate according to claim 19,[[]]END]] Wherein, The display substrate further includes a second dielectric layer on the side of the light guide layer away from the substrate, wherein, The second dielectric layer includes a main body portion and a spacer portion, and the spacer portion is located in the gap between the light guide layers of adjacent sub-pixels; The orthographic projection of the second dielectric layer on the substrate does not overlap with the orthographic projection of the LED light-emitting unit of the first sub-pixel on the substrate; and The orthographic projection of each of the LED light-emitting units of the second sub-pixel and the third sub-pixel on the substrate falls within the orthographic projection of the main body portion of the second dielectric layer on the substrate.

22. The display substrate according to claim 20,[[]]END]] Wherein, The display substrate further includes a second dielectric layer on the side of the light guide layer away from the substrate, Wherein, the second dielectric layer includes a main body portion and a spacer portion, and the spacer portion is located in the gap between the light guide layers of adjacent sub-pixels; and The orthographic projection of each of the LED light-emitting units of the first sub-pixel, the second sub-pixel, and the third sub-pixel on the substrate falls within the orthographic projection of the main body portion of the second dielectric layer on the substrate.

23. The display substrate according to claim 21 or 22,[[]]END]] Wherein, The second dielectric layer includes an SiO 2 layer and a TiO 2 layer in a stacked structure; or, the second dielectric layer includes an SiO 2 layer and a NbO 2 layer in a stacked structure; and / or, The second dielectric layer has a third thickness in the direction perpendicular to the substrate, and the third thickness is less than or equal to 5um.

24. The display substrate according to any one of claims 17-22,[[]]END]] Wherein, The display substrate further includes a first dielectric layer disposed between the LED light-emitting unit and the light guide layer, wherein, The first dielectric layer includes a stacked structure of SiO 2 layer and TiO 2 layer; or, The first dielectric layer includes a stacked structure of an SiO 2 layer and a NbO 2 layer; and / or, The first dielectric layer has a fourth thickness in the direction perpendicular to the substrate, and the fourth thickness is less than or equal to 5um.

25. The display substrate according to any one of claims 17-22,[[]]END]] Wherein, The display substrate further includes a black glue layer disposed on the side of the second dielectric layer away from the substrate, and The black glue layer is located between adjacent sub-pixels and is used to reflect at least a part of the light emitted by the sub-pixels to the side of adjacent sub-pixels.

26. A display device,[[]]END]] Wherein, The display device includes the display substrate according to any one of claims 17-25.

27. A method for manufacturing a display substrate,[[]]END]] Characterized in that,[[]]END]] The method includes: Forming a plurality of LED light-emitting units on a substrate; Forming a first dielectric material layer on the side of the plurality of LED light-emitting units away from the substrate; Depositing different light guide material layers in multiple steps on the side of the first dielectric material layer away from the substrate and performing a patterning process to form light guide material layers corresponding to different LED light-emitting units; Forming a second dielectric layer on the side of the light guide material layer away from the substrate and performing a patterning process; A black glue layer is formed on a side of the second dielectric layer away from the substrate, and a patterning process is performed to form the display substrate.

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