Display substrate, manufacturing method therefor, and display apparatus

Abstract

Provided in the present disclosure are a display substrate, a manufacturing method therefor, and a display apparatus. The display substrate comprises: a plurality of light-emitting sub-pixels arranged in an array, wherein each of the light-emitting sub-pixels comprises a micro light-emitting unit, and at least some of the plurality of light-emitting sub-pixels each comprise a color conversion unit located on the side of a light-emergent surface of a corresponding micro light-emitting unit; and the color conversion unit comprises a plurality of nano pillars arranged in an array, and each of the nano pillars comprises a multi-quantum well structure.

Description

Display substrate, manufacturing method thereof and display device

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410826167.7, filed on June 25, 2024, and entitled "A display substrate, a manufacturing method thereof and a display device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of display, in particular to a display substrate, a manufacturing method thereof and a display device. BACKGROUND

[0004] Low-cost and high-efficiency new Micro Light-Emitting Diode (Micro LED) display technology is the realization way of the next generation of ultra-high-definition display and full-color flexible display. Among them, the color conversion scheme is widely used in LED display field, which can reduce the large amount of red and green transfer, and solve the problem of low red light efficiency. At present, there are many color conversion methods that can realize full-color display of Micro LED. How to realize low-cost and high-efficiency full-color display has become a technical problem to be solved urgently. SUMMARY

[0005] The present disclosure provides a display substrate, a manufacturing method thereof and a display device, and the specific solutions are as follows:

[0006] The present disclosure provides a display substrate, and the specific solutions are as follows:

[0007] a plurality of light-emitting sub-pixels arranged in an array;

[0008] Each of the light-emitting sub-pixels includes a micro light-emitting unit, and at least part of the light-emitting sub-pixels includes a color conversion unit located on one side of a light-emitting surface of the corresponding micro light-emitting unit; the color conversion unit includes a plurality of nanometer columns arranged in an array, and each of the nanometer columns includes a multi-quantum well structure.

[0009] Optionally, in the present disclosure, along the cross-sectional direction parallel to the plane where the micro light-emitting unit is located, the extension length of each of the nanometer columns corresponding to the light-emitting sub-pixels of the same light-emitting color in the at least part of the light-emitting sub-pixels is equal.

[0010] Optionally, in the present disclosure, in the same light-emitting sub-pixel, along the direction of the color conversion unit pointing to the micro light-emitting unit, each of the nanometer columns presents an increasing trend along the cross-sectional area parallel to the plane where the micro light-emitting unit is located.

[0011] Optionally, in the embodiments of the present disclosure, each of the light-emitting sub-pixels is provided with a color conversion unit on the light-emitting surface of the corresponding micro light-emitting unit, and the color conversion units are not overlapped with each other.

[0012] Optionally, in the embodiments of the present disclosure, the color conversion units are arranged in the same layer and are made of the same material.

[0013] Optionally, in the embodiments of the present disclosure, the color conversion units corresponding to the light-emitting sub-pixels of different colors are made of the same material, the color conversion units corresponding to the light-emitting sub-pixels of the same color are arranged in the same layer, and the color conversion units corresponding to the light-emitting sub-pixels of different colors are arranged in different layers.

[0014] Optionally, in the embodiments of the present disclosure, the light-emitting sub-pixels include blue sub-pixels, green sub-pixels and red sub-pixels; the blue sub-pixels include blue light color conversion units located on the side away from the light-emitting surface of the corresponding micro light-emitting unit, the green sub-pixels include green light color conversion units located on the side away from the light-emitting surface of the corresponding micro light-emitting unit, the red sub-pixels include red light color conversion units located on the side away from the light-emitting surface of the corresponding micro light-emitting unit, and the blue light color conversion units, the green light color conversion units and the red light color conversion units are arranged in turn on the side away from the light-emitting surface of the micro light-emitting unit.

[0015] Optionally, in the embodiments of the present disclosure, in the direction parallel to the color conversion units and pointing to the micro light-emitting unit, one end of the red light color conversion unit away from the light-emitting surface of the micro light-emitting unit, one end of the green light color conversion unit away from the light-emitting surface of the micro light-emitting unit, and one end of the blue light color conversion unit away from the light-emitting surface of the micro light-emitting unit, along the cross-sectional area parallel to the plane where the micro light-emitting unit is located, show a decreasing trend.

[0016] Optionally, in the embodiments of the present disclosure, the light-emitting sub-pixels include blue sub-pixels, green sub-pixels and red sub-pixels, each of the micro light-emitting units is a blue light-emitting device capable of emitting blue light, and only the green sub-pixels and the red sub-pixels are provided with color conversion units corresponding to the corresponding micro light-emitting units; the green sub-pixels include green light color conversion units located on the side away from the light-emitting surface of the corresponding micro light-emitting unit, the red sub-pixels include red light color conversion units located on the side away from the light-emitting surface of the corresponding micro light-emitting unit, and the green light color conversion units and the red light color conversion units are arranged in turn on the side away from the light-emitting surface of the micro light-emitting unit.

[0017] Optionally, in the embodiments of the present disclosure, a first distributed Bragg reflector is further arranged on a light emitting surface of each micro light emitting unit, and the first distributed Bragg reflector is configured to transmit blue light and reflect red and green light.

[0018] Optionally, in the embodiments of the present disclosure, a second distributed Bragg reflector is further arranged on a side of the red light color conversion unit away from the micro light emitting unit, and the second distributed Bragg reflector is configured to transmit red and green light and reflect blue light.

[0019] Optionally, in the embodiments of the present disclosure, an anti-crosstalk layer is further arranged around each micro light emitting unit, and the anti-crosstalk layer does not overlap with the color conversion unit.

[0020] Correspondingly, the embodiments of the present disclosure provide a light emitting chip, which comprises:

[0021] a micro light emitting unit and a color conversion unit arranged on a light emitting surface of the micro light emitting unit.

[0022] The color conversion unit comprises a plurality of nanometer columns arranged in an array, and each nanometer column comprises a multi-quantum well structure.

[0023] Optionally, in the embodiments of the present disclosure, along a direction of the color conversion unit pointing to the micro light emitting unit, each nanometer column has an increasing cross-sectional area parallel to a plane where the micro light emitting unit is located.

[0024] Optionally, in the embodiments of the present disclosure, a distributed Bragg reflector is further arranged between the micro light emitting unit and the color conversion unit, and the distributed Bragg reflector completely covers the micro light emitting unit.

[0025] Optionally, in the embodiments of the present disclosure, a first bonding unit is further arranged between the distributed Bragg reflector and the color conversion unit, a second bonding unit is arranged around each nanometer column, and a substrate is arranged on a light emitting surface of the plurality of nanometer columns and the second bonding unit away from the micro light emitting unit.

[0026] Correspondingly, the embodiments of the present disclosure provide a display device, which comprises:

[0027] The display substrate as in any of the preceding items, and a driving backplane electrically connected with the display substrate.

[0028] Optionally, in the display substrate, each micro light emitting unit comprises a N-type gallium nitride layer, a quantum well layer and a P-type gallium nitride layer along a direction from the display substrate to the driving backplane; the P-type gallium nitride layer is provided with a transparent electrode layer on a side away from a light emitting surface of the micro light emitting unit, the transparent electrode layer is electrically connected with a first connecting electrode, and a portion of the N-type gallium nitride layer that does not overlap with the P-type gallium nitride layer is electrically connected with a second connecting electrode; each micro light emitting unit is electrically connected with the driving backplane through the corresponding first connecting electrode and the second connecting electrode.

[0029] Correspondingly, the display substrate manufacturing method provided by the embodiments of the present disclosure comprises the following steps:

[0030] forming a plurality of light emitting sub-pixels arranged in an array, each of the light emitting sub-pixels comprising a micro light emitting unit;

[0031] forming a color conversion unit on a side of the light emitting surface of the micro light emitting unit corresponding to at least part of the light emitting sub-pixels; wherein the color conversion unit comprises a plurality of nanometer columns arranged in an array, and each of the nanometer columns comprises a multi-quantum well structure.

[0032] Optionally, in the display substrate, forming a color conversion unit on a side of the light emitting surface of the micro light emitting unit corresponding to at least part of the light emitting sub-pixels comprises:

[0033] growing a buffer layer on a substrate;

[0034] growing a multi-quantum well structure on the buffer layer;

[0035] depositing a mask layer and a nano-imprint glue on a side of the multi-quantum well structure away from the buffer layer;

[0036] patterning the nano-imprint glue by a nano-imprint process to form a patterned nano-imprint glue;

[0037] etching the mask layer and the multi-quantum well structure according to the patterned nano-imprint glue to form a plurality of nanometer columns arranged in an array;

[0038] removing the mask layer and the nano-imprint glue;

[0039] bonding the plurality of nanometer columns to a side of the light emitting surface of the micro light emitting unit corresponding to at least part of the light emitting sub-pixels to form a color conversion unit comprising the plurality of nanometer columns, removing the substrate, and thinning the buffer layer. BRIEF DESCRIPTION OF DRAWINGS

[0040] FIG. 1 is a schematic diagram of one kind of top view structure of the display substrate provided by the embodiments of the present disclosure;

[0041] Fig. 2 is a schematic view of one of the cross-sectional structures along the direction indicated by MM in Fig. 1;

[0042] Fig. 3 is a schematic view of one of the structures of the region in Fig. 2;

[0043] Fig. 4 is a schematic view of one of the structures of a display substrate according to an embodiment of the present disclosure;

[0044] Fig. 5 is a schematic view of one of the structures of a display substrate according to an embodiment of the present disclosure;

[0045] Fig. 6 is a schematic view of one of the structures of a display substrate according to an embodiment of the present disclosure;

[0046] Fig. 7 is a schematic view of one of the structures of a light emitting chip according to an embodiment of the present disclosure;

[0047] Fig. 8 is a flowchart of a chip process for preparing the light emitting chip shown in Fig. 7;

[0048] Fig. 9 is a flowchart of a temporary bonding and substrate removing process for preparing the light emitting chip shown in Fig. 7;

[0049] Fig. 10 is a flowchart of a color conversion unit preparation process for preparing the light emitting chip shown in Fig. 7;

[0050] Fig. 11 is a flowchart of a color conversion unit and micro light emitting unit bonding process for preparing the light emitting chip shown in Fig. 7;

[0051] Fig. 12 is a flowchart of a chip segmentation process for preparing the light emitting chip shown in Fig. 7;

[0052] Fig. 13 is a schematic view of one of the structures of a display device based on the display substrate shown in Fig. 6;

[0053] Fig. 14 is a flowchart of a method of a display substrate manufacturing method according to an embodiment of the present disclosure;

[0054] Fig. 15 is a flowchart of one of the methods of step S102 in Fig. 14;

[0055] Fig. 16 is a flowchart of one of the methods of step S102 in Fig. 14;

[0056] Fig. 17 is a flowchart of one of the processes corresponding to Fig. 16 when preparing the display substrate shown in Fig. 2;

[0057] Fig. 18 is a flowchart of a blue light color conversion process for preparing a display device;

[0058] Fig. 19 is a flowchart of a violet light color conversion process for preparing a display device;

[0059] FIG. 20 is a process flow diagram for applying the light emitting chip in the embodiment of the present disclosure to a three-in-one blue light chip process;

[0060] FIG. 21 is a process flow diagram for applying the light emitting chip in the embodiment of the present disclosure to a three-in-one full-color display preparation process. DETAILED DESCRIPTION

[0061] In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. And the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict. Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present disclosure.

[0062] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood as the usual meaning understood by those skilled in the art to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not represent any order, number or importance, but are only used to distinguish different components. "Include" or "contain" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "In", "out", "up", "down" and the like only represent relative positional relationships, which may change accordingly when the absolute position of the described object changes.

[0063] It should be noted that the size and shape of each figure in the drawings do not reflect the true proportions, but only serve to illustrate the present disclosure. And the same or similar reference numbers represent the same or similar elements or elements with the same or similar functions throughout.

[0064] In the related art, quantum dot (QD) color conversion, quantum well layer color conversion and other color conversion methods can be used to realize full-color display of Micro LED. Among them, using the QD color conversion method, not only is there a risk of thick display device and color bar, but also after using ink and photo resist (PR) curing, the related glue materials have problems such as poor temperature resistance and poor reliability. And using the quantum well layer color conversion method, since different materials need to be used to grow the corresponding multi-quantum well structure of the light color, there are problems such as complex preparation process, high cost and poor stability.

[0065] Therefore, the display substrate, the manufacturing method thereof and the display device are provided to improve the preparation efficiency of the display substrate while ensuring full-color display.

[0066] In combination with FIG. 1 and FIG. 2, FIG. 1 is a schematic diagram of a top view of one of the display substrates, and FIG. 2 is a schematic diagram of one of the cross-sectional structures along the direction of MM in FIG. 1. Specifically, the display substrate includes:

[0067] a plurality of light-emitting sub-pixels sp arranged in an array;

[0068] Each of the light-emitting sub-pixels sp includes a micro light-emitting unit 10, and at least part of the light-emitting sub-pixels sp in the plurality of light-emitting sub-pixels sp includes a color conversion unit 20 located on one side of a light-emitting surface of the corresponding micro light-emitting unit 10. The color conversion unit 20 includes a plurality of nanometer columns 30 arranged in an array, and each of the nanometer columns 30 includes a multi-quantum well structure 40.

[0069] In the implementation process, the display substrate includes a plurality of light-emitting sub-pixels sp arranged in an array. The specific number of the plurality of light-emitting sub-pixels sp can be set according to actual application needs, which is not limited herein. In addition, the plurality of light-emitting sub-pixels sp includes light-emitting sub-pixels sp with different light-emitting colors. For example, the plurality of light-emitting sub-pixels sp includes red sub-pixels R, green sub-pixels G and blue sub-pixels B. One red sub-pixel R, one green sub-pixel G and one blue sub-pixel B can form one light-emitting pixel, thereby ensuring the color display of the display substrate. Of course, the form of the single light-emitting pixel can be set according to actual application needs, and the light-emitting sub-pixels sp are set accordingly, which is not described in detail herein.

[0070] Furthermore, each of the light-emitting sub-pixels sp includes a micro light-emitting unit 10, and at least part of the light-emitting sub-pixels sp in the plurality of light-emitting sub-pixels sp includes a color conversion unit 20 located on one side of a light-emitting surface of the corresponding micro light-emitting unit 10. For example, part of the light-emitting sub-pixels sp in the plurality of light-emitting sub-pixels sp includes a color conversion unit 20 located on one side of a light-emitting surface of the corresponding micro light-emitting unit 10. For example, each of the light-emitting sub-pixels sp in the plurality of light-emitting sub-pixels sp includes a color conversion unit 20 located on one side of a light-emitting surface of the corresponding micro light-emitting unit 10. In this way, the color conversion unit 20 can convert the color of the light emitted by the corresponding micro light-emitting unit 10 into the color required by the light-emitting sub-pixel sp, thereby ensuring full-color display.

[0071] In addition, the color conversion unit 20 comprises a plurality of nanometer columns 30 arranged in an array. Of course, the specific number and arrangement of the plurality of nanometer columns 30 can be set according to actual application needs, which is not limited herein. Each nanometer column 30 comprises a multi-quantum well structure 40. For example, the multi-quantum well structure 40 is an InGaN / GaN multi-layer quantum well structure.

[0072] It should be noted that the inventors have found in actual research that InN cannot be grown on m-plane (i.e. the plane direction of GaN crystal growth) GaN at a temperature higher than 430℃, and GaN is usually grown at a temperature higher than 700℃. In this way, when the quantum well is grown at a temperature of 650℃, the desorption of In is significantly accelerated, and the desorption of Ga is inhibited, indicating that the diffusion length of In is short. Therefore, Ga atoms preferentially diffuse to the sidewall and are absorbed to the top of the nanometer column 30; as the diameter of the nanometer column 30 increases, the number of Ga beams hitting the sidewall decreases due to the shadow effect, so that the decrease in the top supply of Ga atoms leads to an increase in the In content in the InGaN quantum well; in this way, as the diameter of the nanometer column 30 increases, the In content of InGaN gradually increases, thereby causing a change in the emission wavelength. Accordingly, the larger the diameter of the nanometer column 30, the more the In content, and the larger the emission wavelength, i.e. the diameter of the nanometer column 30 is proportional to the emission wavelength.

[0073] The inventors have found in actual research that in the actual preparation process, the diameter of the nanometer column 30 can be adjusted to adjust the light-emitting color of the corresponding micro light-emitting unit 10, thereby obtaining a light-emitting sub-pixel sp of a desired color. In this way, the emission of red light and green light can be realized by adjusting the diameter of the nanometer column 30, and the overall preparation efficiency is relatively high. Moreover, the multi-quantum well structure 40 in the form of the nanometer column 30 is used as the color conversion unit 20, and the entire preparation process can realize all-inorganic color conversion, and the stability is relatively high. In particular, when the same material is used to grow and prepare color conversion units 20 corresponding to light-emitting sub-pixels sp of different colors, the preparation cost is relatively low, and the preparation efficiency is relatively high.

[0074] In the embodiments of the present disclosure, along a cross-sectional direction parallel to the plane in which the micro light-emitting unit 10 is located, the extension length of each nanometer column 30 corresponding to light-emitting sub-pixels sp of the same light-emitting color in the at least part of the light-emitting sub-pixels sp is equal.

[0075] Still in combination with the exemplary embodiment shown in FIG. 2, FIG. 3 is a magnified schematic view of one of the structures of the region Q in FIG. 2, and the direction shown by the arrow X is the cross-sectional direction parallel to the plane in which the micro light emitting units 10 are located. In the at least part of the light emitting sub-pixels sp in which the color conversion units 20 are arranged, the extension lengths of the respective nanorods 30 corresponding to the light emitting sub-pixels sp of the same light emitting color are equal in the direction. For example, the respective nanorods 30 are arranged in the shape of a circular truncated cone, and the diameters of the respective nanorods 30 corresponding to the color conversion units 20 of the respective green sub-pixels are equal. It should be noted that the "equal" mentioned herein can be approximately equal, and is not limited herein.

[0076] In one of the exemplary embodiments, in the same light emitting sub-pixel sp, the respective nanorods 30 have an increasing trend in the cross-sectional area parallel to the plane in which the micro light emitting units 10 are located in the direction in which the color conversion units 20 point to the micro light emitting units 10.

[0077] Still in combination with the exemplary embodiment shown in FIG. 3, for the same green sub-pixel G, the respective nanorods 30 have an increasing trend in the cross-sectional area parallel to the plane in which the corresponding micro light emitting unit 10 is located in the direction in which the color conversion unit 20 points to the micro light emitting unit 10 (the direction shown by the arrow Y in the figure).

[0078] It should be noted that the cross-sectional shape of the respective nanorods 30 parallel to the plane in which the micro light emitting units 10 are located can be at least one of a circular shape, a triangular shape, and a hexagonal shape, and of course, the cross-sectional shape of the respective nanorods 30 can also be arranged according to actual application requirements, and is not limited herein.

[0079] In the embodiments of the present disclosure, the color conversion units 20 can be arranged in the following manner, but are not limited thereto.

[0080] In one of the exemplary embodiments, the light emitting surface side of the micro light emitting unit 10 corresponding to each of the light emitting sub-pixels sp is provided with the color conversion unit 20, and the respective color conversion units 20 do not overlap with each other.

[0081] In combination with the exemplary embodiments shown in FIG. 4 and FIG. 5, the light emitting surface side of the micro light emitting unit 10 corresponding to each of the light emitting sub-pixels sp is provided with the color conversion unit 20, and the respective color conversion units 20 do not overlap with each other.

[0082] Still in combination with the example embodiment shown in FIG. 4, each of the color conversion units 20 is arranged in the same layer and made of the same material. In this way, if the plurality of light emitting sub-pixels sp includes red sub-pixels R, green sub-pixels G and blue sub-pixels B, in actual production, the nano-pillar 30 multi-quantum well structure 40 of the required structure can be grown in the same material to obtain the color conversion unit 20 of the required structure. In actual production, the epitaxial layer 97 grown in the same material can be used to produce the color conversion unit 20 required by the light emitting sub-pixel sp of various colors, thereby improving the production efficiency of the color conversion unit 20. In addition, each color conversion unit 20 can also be arranged in the same layer, thereby providing a guarantee for the lightweight design of the subsequent display substrate.

[0083] Still in combination with the example embodiment shown in FIG. 5, the color conversion units 20 corresponding to the light emitting sub-pixels sp of various light emitting colors in the plurality of light emitting sub-pixels sp are arranged in the same material, the color conversion units 20 corresponding to the light emitting sub-pixels sp of the same light emitting color in the plurality of light emitting sub-pixels sp are arranged in the same layer, and the color conversion units 20 corresponding to the light emitting sub-pixels sp of different light emitting colors in the plurality of light emitting sub-pixels sp are arranged in different layers.

[0084] Still in combination with the example embodiment shown in FIG. 5, if the plurality of light emitting sub-pixels sp includes red sub-pixels R, green sub-pixels G and blue sub-pixels B, in actual production, the nano-pillar 30 multi-quantum well structure 40 of the required structure can be grown in the same material to obtain the color conversion unit 20 of the required structure, thereby reducing the production efficiency of the color conversion unit 20. In addition, the color conversion units 20 corresponding to each red sub-pixel R are arranged in the same layer, the color conversion units 20 corresponding to each green sub-pixel G are arranged in the same layer, the color conversion units 20 corresponding to each blue sub-pixel B are arranged in the same layer, and the color conversion units 20 corresponding to the red sub-pixels R, the color conversion units 20 corresponding to the green sub-pixels G and the color conversion units 20 corresponding to the blue sub-pixels B are arranged in different layers. In this way, the color conversion units 20 corresponding to all blue sub-pixels B can be produced in the same layer and the same material, the color conversion units 20 corresponding to all green sub-pixels G can be produced in the same layer and the same material, and the color conversion units 20 corresponding to all red sub-pixels R can be produced in the same layer and the same material, thereby improving the production efficiency of the color conversion units 20 corresponding to each layer of sub-pixels. In addition, the color conversion units 20 corresponding to the micro light emitting units 10 of the blue sub-pixels B, the color conversion units 20 corresponding to the green sub-pixels G and the color conversion units 20 corresponding to the red sub-pixels R are arranged in different layers, which takes into account full-color display while avoiding the mutual influence of the color conversion units 20 corresponding to the light emitting sub-pixels sp of different colors in production.

[0085] Still in combination with the exemplary embodiment shown in FIG. 5, the plurality of light-emitting sub-pixels sp includes a blue sub-pixel B, a green sub-pixel G, and a red sub-pixel R; the blue sub-pixel B includes a blue light color conversion unit 2050 located on a side away from a light-emitting surface of a corresponding micro light-emitting unit 10, the green sub-pixel G includes a green light color conversion unit 60 located on a side away from a light-emitting surface of a corresponding micro light-emitting unit 10, and the red sub-pixel R includes a red light color conversion unit 70 located on a side away from a light-emitting surface of a corresponding micro light-emitting unit 10, and the blue light color conversion unit 50, the green light color conversion unit 60, and the red light color conversion unit 70 are sequentially arranged on a side away from the light-emitting surface of the micro light-emitting unit 10.

[0086] In the exemplary embodiment shown in FIG. 5, the blue light color conversion unit 50, the green light color conversion unit 60, and the red light color conversion unit 70 are sequentially arranged on a side away from the light-emitting surface of the micro light-emitting unit 10. Accordingly, the blue light color conversion unit 50 is closer to the light-emitting surface of the micro light-emitting unit 10, and the red light color conversion unit 70 is farther away from the light-emitting surface of the micro light-emitting unit 10. In this way, part of the blue light leaked through the blue light color conversion unit 50 can be absorbed by the green light color conversion unit 60, and part of the green light leaked through the green light color conversion unit 60 can be absorbed by the red light color conversion unit 70, thereby improving the light utilization rate while taking into account full-color display. It should be noted that in the exemplary embodiment shown in FIG. 5, each micro light-emitting unit 10 can be an ultraviolet light-emitting device for emitting ultraviolet light.

[0087] In the embodiments of the present disclosure, along a direction parallel to the color conversion unit 20 pointing to the micro light-emitting unit 10, the red light color conversion unit 70 is away from one end of the light-emitting surface of the micro light-emitting unit 10, the green light color conversion unit 60 is away from one end of the light-emitting surface of the micro light-emitting unit 10, and the blue light color conversion unit 50 is away from one end of the light-emitting surface of the micro light-emitting unit 10, and along a cross-sectional area parallel to the plane where the micro light-emitting unit 10 is located, the cross-sectional area decreases.

[0088] Still in combination with the exemplary embodiment shown in FIG. 5, for example, along a direction parallel to the color conversion unit 20 pointing to the micro light-emitting unit 10, the red light color conversion unit 70 is away from one end of the light-emitting surface of the micro light-emitting unit 10, and along a cross-sectional area parallel to the plane where the micro light-emitting unit 10 is located, the cross-sectional area is s1, the green light color conversion unit 60 is away from one end of the light-emitting surface of the micro light-emitting unit 10, and along a cross-sectional area parallel to the plane where the micro light-emitting unit 10 is located, the cross-sectional area is s2, and the blue light color conversion unit 50 is away from one end of the light-emitting surface of the micro light-emitting unit 10, and along a cross-sectional area parallel to the plane where the micro light-emitting unit 10 is located, the cross-sectional area is s3, where s1>s2>s3. Of course, the specific values of s1, s2, and s3 can be set according to actual application needs, which are not limited herein.

[0089] In the exemplary embodiment shown in FIG. 5, if the nano-pillar 30 corresponding to each color conversion unit 20 is a truncated cone structure, the diameter of the nano-pillar 30 corresponding to the red color conversion unit 70 ranges from 220 nm to 270 nm, the diameter of the nano-pillar 30 corresponding to the green color conversion unit 60 ranges from 175 nm to 295 nm, and the diameter of the nano-pillar 30 corresponding to the blue color conversion unit 50 ranges from 135 nm to 150 nm. Of course, the specific diameter of each nano-pillar 30 can be set according to actual application needs, which is not limited herein.

[0090] In the exemplary embodiment shown in FIG. 6, the plurality of light-emitting sub-pixels sp include a blue sub-pixel B, a green sub-pixel G, and a red sub-pixel R, and each micro light-emitting unit 10 is a blue light-emitting device capable of emitting blue light, and only the green sub-pixel G and the red sub-pixel R are provided with a color conversion unit 20 corresponding to the corresponding micro light-emitting unit 10; the green sub-pixel G includes a green light color conversion unit 60 located on the side of the light-emitting surface away from the corresponding micro light-emitting unit 10, the red sub-pixel R includes a red light color conversion unit 70 located on the side of the light-emitting surface away from the corresponding micro light-emitting unit 10, and the green light color conversion unit 60 and the red light color conversion unit 70 are sequentially provided on the side of the light-emitting surface away from the micro light-emitting unit 10.

[0091] Still in combination with the exemplary embodiment shown in FIG. 6, each micro light-emitting unit 10 is a blue light-emitting device capable of emitting blue light, so that the side of the light-emitting surface of the micro light-emitting unit 10 corresponding to the blue sub-pixel B does not need to be provided with a corresponding color conversion unit 20. Among them, only the green sub-pixel G and the red sub-pixel R are provided with a color conversion unit 20 corresponding to the corresponding micro light-emitting unit 10. Correspondingly, the green sub-pixel G includes a green light color conversion unit 60 located on the side of the light-emitting surface away from the corresponding micro light-emitting unit 10, the red sub-pixel R includes a red light color conversion unit 70 located on the side of the light-emitting surface away from the corresponding micro light-emitting unit 10, and the green light color conversion unit 60 and the red light color conversion unit 70 are sequentially provided on the side of the light-emitting surface away from the micro light-emitting unit 10, so that the green light color conversion unit 60 is closer to the side of the light-emitting surface of the micro light-emitting unit 10. In this way, the green light leaked by the green light color conversion unit 60 can be absorbed by the red light color conversion unit 70, thereby improving the light utilization while taking into account full-color display.

[0092] In the embodiment of the present disclosure, the display substrate further comprises a first distributed Bragg reflector 80 located on the side of the light-emitting surface of each micro light-emitting unit 10, and the first distributed Bragg reflector 80 is configured to transmit blue light and reflect red and green light.

[0093] Still in combination with the exemplary embodiments shown in FIGS. 4-6, the display substrate further includes a first distributed Bragg reflector 80 located on the side of the light exit surface of each micro light emitting unit 10. The first distributed Bragg reflector 80 includes a plurality of first repeating units stacked in sequence, each first repeating unit including a first dielectric layer and a second dielectric layer in sequence adjacent to the light exit surface of the micro light emitting unit 10, wherein the first dielectric layer has a smaller refractive index than the second dielectric layer. Moreover, the first distributed Bragg reflector 80 is configured to transmit blue light and reflect red and green light. Exemplarily, the first distributed Bragg reflector 80 includes two first repeating units stacked in sequence, the first dielectric layer in each first repeating unit is SiO2 with a thickness of 77 nm, and the second dielectric layer is TiO2 with a thickness of 48 nm. Exemplarily, the first dielectric layer in each first repeating unit can also be SiO2, and the second dielectric layer can also be Nb2O5. Exemplarily, the first dielectric layer in each first repeating unit can also be SiO2, and the second dielectric layer can also be SiN. Of course, the related dielectric layers in the first distributed Bragg reflector 80 can also be set according to actual application needs, which will not be described in detail here.

[0094] In the embodiments of the present disclosure, the display substrate further includes a second distributed Bragg reflector 90 located on the side of the red light color conversion unit 70 away from the micro light emitting unit 10, and the second distributed Bragg reflector 90 is configured to transmit red and green light and reflect blue light.

[0095] Still in combination with the exemplary embodiments shown in FIGS. 5 and 6, the display substrate further includes a second distributed Bragg reflector 90 located on the side of the red light color conversion unit 70 away from the micro light emitting unit 10. The second distributed Bragg reflector 90 includes a plurality of second repeating units stacked in sequence, each second repeating unit including a third dielectric layer and a fourth dielectric layer in sequence adjacent to the light exit surface of the micro light emitting unit 10, wherein the third dielectric layer has a smaller refractive index than the fourth dielectric layer. Moreover, the second distributed Bragg reflector 90 is configured to transmit red and green light and reflect blue light. Exemplarily, the second distributed Bragg reflector 90 includes five second repeating units stacked in sequence, the third dielectric layer in each second repeating unit is SiO2 with a thickness of 77 nm, and the fourth dielectric layer is TiO2 with a thickness of 48 nm. Exemplarily, the third dielectric layer in each second repeating unit can also be SiO2, and the fourth dielectric layer can also be Nb2O5. Exemplarily, the third dielectric layer in each second repeating unit can also be SiO2, and the fourth dielectric layer can also be SiN. Of course, the related dielectric layers in the second distributed Bragg reflector 90 can also be set according to actual application needs, which will not be described in detail here.

[0096] In the embodiments of the present disclosure, the display substrate further comprises an anti-crosstalk layer 91 arranged around each micro light emitting unit 10, and the anti-crosstalk layer 91 and the color conversion unit 20 do not overlap with each other.

[0097] Still in combination with the exemplary embodiments shown in FIGS. 5 and 6, the display substrate further comprises an anti-crosstalk layer 91 arranged around each micro light emitting unit 10. Exemplarily, the anti-crosstalk layer 91 can be a black barrier, can also be a gray barrier, and can also be a white barrier, which is not limited herein. Moreover, the anti-crosstalk layer 91 and the color conversion unit 20 do not overlap with each other, so as to avoid color leakage while taking into account the light emitting efficiency, and ensure the display effect.

[0098] It should be noted that in the exemplary embodiments shown in FIGS. 2 to 6, the display substrate further comprises a bonding layer between the first distributed Bragg reflector 80 and the color conversion unit 20, and the color conversion unit 20 and the corresponding micro light emitting unit 10 can be bonded together through the bonding layer. In the actual bonding process, the bonding pressure can be selected in the range of 4000N-15000N, and the temperature of the bonding process can be selected according to the requirements of the adhesive material, and the temperature is generally not more than 300°C.

[0099] In the exemplary embodiment shown in FIG. 5, a first bonding layer 92 is further arranged between the first distributed Bragg reflector 80 and the blue light color conversion unit 50, a second bonding layer 93 is further arranged between the green light color conversion unit 60 and the blue light color conversion unit 50, and a third bonding layer 94 is further arranged between the red light color conversion unit 70 and the green light color conversion unit 60. In this way, the corresponding color conversion unit 20 and the corresponding micro light emitting unit 10 are bonded together through the first bonding layer 92, the second bonding layer 93 and the third bonding layer 94. Exemplarily, the material of the first bonding layer 92, the second bonding layer 93 and the third bonding layer 94 can be transparent adhesive material. In the bonding process, the bonding pressure can be greater than 0.05N, and the light transmittance can be greater than 95%, and the corresponding bonding layer can be arranged at the corresponding position by using a spin coating method.

[0100] In the exemplary embodiment shown in FIG. 6, a first bonding layer 92 is further arranged between the first distributed Bragg reflector 80 and the green light color conversion unit 60, and a second bonding layer 93 is further arranged between the green light color conversion unit 60 and the red light color conversion unit 70. The green light color conversion unit 60 and the corresponding micro light emitting unit 10 are bonded together through the first bonding layer 92, and the red light color conversion unit 70 and the green light color conversion unit 60 are bonded together through the second bonding layer 93. Exemplarily, the material of the first bonding layer 92 and the second bonding layer 93 can be transparent adhesive material.

[0101] Of course, the display substrate provided by the embodiments of the present disclosure can further include other film layer structures according to actual application requirements in addition to the film layer structure mentioned above, and specific settings can be implemented by referring to related technologies.

[0102] Based on the same disclosure concept, as shown in FIG. 7, the embodiments of the present disclosure further provide a light-emitting chip, which comprises:

[0103] a micro light-emitting unit 10 and a color conversion unit 20 located on the light-emitting surface side of the micro light-emitting unit 10;

[0104] The color conversion unit 20 comprises a plurality of nanorods 30 arranged in an array, and each nanorod 30 comprises a multi-quantum well structure 40.

[0105] In the specific implementation process, the specific settings of the color conversion unit 20 and the nanorod 30 structure can be referred to the description of the foregoing related parts, which will not be repeated here. The single micro light-emitting unit 10 comprises an N-type gallium nitride layer, a quantum well layer 972 and a P-type gallium nitride layer 973 arranged in sequence.

[0106] The specific preparation process of the light-emitting chip shown in FIG. 7 will be explained in detail in combination with the chip process shown in FIG. 8, the temporary bonding and substrate removal process shown in FIG. 9, the color conversion unit 20 preparation process shown in FIG. 10, the color conversion unit 20 and micro light-emitting unit 10 bonding process shown in FIG. 11, and the chip segmentation process shown in FIG. 12.

[0107] First, in combination with the chip process shown in FIG. 8, a buffer layer gallium nitride 96 (i.e., a buffer layer 41) is grown on a sapphire substrate 95, and an epitaxial layer 97 is grown on the buffer layer gallium nitride 96, the epitaxial layer 97 comprising an N-type gallium nitride layer 971, a quantum well layer 972 and a P-type gallium nitride layer 973; then, an Indium Tin Oxide (ITO) electrode layer is deposited on the side of the P-type gallium nitride layer 973 away from the N-type gallium nitride layer 971; then, N mesa etching is performed, including ITO electrode layer 98 etching and gallium nitride layer etching, wherein the ITO electrode layer 98 can be etched by a dry etching process or a wet etching process, and the gallium nitride layer can be inductively coupled plasma (ICP) etched by Cl2 / BCl3 gas until the N-type gallium nitride layer 971 is etched. Exemplarily, the etching depth is 0.8 μm-0.9 μm.

[0108] Then, the N electrode 99 is prepared on the exposed N-type GaN layer 971; for example, the N electrode 99 can be prepared by using a Ti / Al / Ni / Au metal film system, or by using a Cr / Pt / Au metal film system. Of course, the N electrode 99 can also be prepared according to actual application requirements, which are not limited herein. In the actual preparation process, the related metal film system can also be subjected to high-temperature annealing, so as to form a good ohmic contact.

[0109] Then, the passivation layer 992 is deposited and the passivation layer 992 is subjected to opening; for example, the SiO or SiN can be deposited by using a plasma enhanced chemical vapor deposition (PECVD) process, so as to form the passivation layer 992; then, the etching process is used to open the passivation layer 992, so as to form the electrode opening.

[0110] Then, the N Pad 990 (i.e., a connection electrode electrically connected with the N electrode 99) and the P Pad 991 (i.e., a connection electrode electrically connected with the ITO electrode layer 98) are prepared; for example, the N Pad 990 and the P Pad 991 are prepared by using a Ti / Al / Ni / Au metal film system, which are used as thickened electrodes, so as to be electrically connected with the driving backboard 200 through the N Pad 990 and the P Pad 991 in the subsequent process.

[0111] Then, deep etching is performed; for example, the ICP method is used to etch the chip cutting path position to the sapphire substrate 95, and the etching depth can be 4 μm-5 μm, which is not limited herein.

[0112] After the related process of FIG. 8 is used, the temporary bonding substrate removal process shown in FIG. 9 is used; first, the glass or sapphire is used as a temporary carrier 600, and the temporary bonding glue material 993 is used to achieve temporary bonding. Then, the laser lift off (LLO) method is used to remove the original sapphire substrate 95, so as to expose the light emitting surface of the micro light emitting unit 10.

[0113] After the related process of FIG. 9, the color conversion unit 20 shown in FIG. 11 is bonded with the micro light emitting unit 10. First, a distributed Bragg reflection (DBR) mirror is prepared on the micro light emitting unit 10 array, which functions to transmit blue light and reflect red and green light. The DBR mirror can be composed of two medium layers with large refractive index difference repeatedly stacked. For example, the two medium layers can be a combination of SiN and SiO2, or a combination of Nb2O5 and SiO2, or a combination of TiO2 and SiO2. In actual applications, the film thickness of each medium layer can be adjusted to achieve high transmission of blue light and high reflection of red and green light.

[0114] Then, the color conversion unit 20 with nano-pillar 30 structure is prepared on the side of the DBR mirror away from the light emitting surface of the micro light emitting unit 10. In one example, the color conversion unit 20 can be prepared using the process shown in FIG. 10. First, a 2-3 μm buffer layer 41 is grown on the sapphire substrate 95. Then, a whole layer of InGaN / GaN multi-quantum well structure 42 (for forming the multi-quantum well structure 40) is grown at a temperature of 650°C. Then, a mask layer 43 and a nano-imprint glue 44 are deposited. For example, the mask layer 43 can be SiO. The nano-imprint glue is patterned by nano-imprinting, and then etched down to the mask layer 43 and the multi-quantum well structure 40. For example, the first type of nano-pillar 30, the second type of nano-pillar 30 and the third type of nano-pillar 30 can be prepared, wherein the diameter of the first type of nano-pillar 30 is 135-150 nm, the diameter of the second type of nano-pillar 30 is 175-295 nm, and the diameter of the third type of nano-pillar 30 is 220-270 nm. The nano-pillars 30 are arranged periodically, for example, the arrangement pitch of the nano-pillars 30 is 1 μm, which includes the distance between adjacent two nano-pillars 30 and the diameter of a single nano-pillar 30. Then, the mask layer 43 and the nano-imprint glue 44 are removed, thereby obtaining the corresponding color conversion unit 20.

[0115] After the color conversion unit 20 of the required structure is obtained, the color conversion unit 20 is bonded with the micro light emitting unit 10 array, for example, by a permanent bonding layer. The specific bonding process can be performed under a certain pressure and temperature, and the bonding pressure is generally 4000N-15000N. The specific temperature value can be selected according to the requirements of the glue material, and the temperature value is generally not more than 300°C. After bonding, the sapphire substrate 95 and the buffer layer 41 are removed. For example, the sapphire substrate 95 can be removed by LLO, and the buffer layer 41 can be thinned by ICP etching. Then, the photoresist 45 is formed into a patterned protection. Then, the ICP etching method is used to realize the patterning of the micro light emitting unit 10 corresponding to the color conversion unit 20, so as to obtain a structure including the patterned color conversion unit 20. For example, Cl2 / BCl3 mixed gas can be used for ICP etching, and the control of the ICP etching rate can be realized by adjusting the power.

[0116] After the structure including the patterned color conversion unit 20 is obtained, the chip segmentation process shown in FIG. 12 is used to obtain a single color conversion light emitting chip. First, the structure including the patterned color conversion unit 20 is permanently bonded. For example, glass is used as a carrier, and permanent bonding glue is used to bond the glass with the structure including the patterned color conversion unit 20; then, the LLO process is used to remove the temporary carrier 600, and the temporary bonding glue is removed by ashing etching, so as to expose the connection electrodes (i.e., N Pad 990 / P Pad 991) of each micro light emitting unit 10; then, the substrate is thinned; the glass substrate is thinned to below 100μm, which provides convenience for subsequent laser cutting and dicing; then, laser cutting is used to realize the segmentation of a single chip, so as to obtain a light emitting chip of the required structure.

[0117] In an exemplary embodiment, in the direction of the color conversion unit 20 pointing to the micro light emitting unit 10, each of the nanorods 30 has an increasing trend in the cross-sectional area parallel to the plane where the micro light emitting unit 10 is located.

[0118] In the embodiments of the present disclosure, the light emitting chip further includes a distributed Bragg reflector between the micro light emitting unit 10 and the color conversion unit 20, and the distributed Bragg reflector completely covers the micro light emitting unit 10.

[0119] In the embodiments of the present disclosure, the light emitting chip further comprises a first bonding unit 46 between the distributed Bragg reflector and the color conversion unit 20, a second bonding unit 47 arranged around each of the plurality of nanorods 30, and a substrate 48 on the side of the plurality of nanorods 30 and the second bonding unit 47 away from the light emitting surface of the micro light emitting unit 10. For example, the substrate 48 can be the aforementioned buffer layer 41 of gallium nitride 96.

[0120] It should be noted that the specific structure of the nanorod 30, the distributed Bragg reflector, the first bonding unit 46 (which can be the aforementioned first bonding layer 92), and the second bonding unit 47 (which can be the aforementioned second bonding layer 93) can refer to the related description in the aforementioned display substrate, and will not be repeated here.

[0121] It should be noted that in actual preparation, after obtaining the aforementioned light emitting chip (in fact, a single color conversion chip), the light emitting chip can be mass transferred to realize the preparation of a full-color display display substrate. In the specific implementation process, the light emitting chip can be a flip structure.

[0122] Based on the same disclosure concept, taking the display substrate 100 shown in FIG. 6 as an example, the display device can be as shown in FIG. 13. Specifically, the embodiments of the present disclosure also provide a display device, which comprises the display substrate 100 as described in any one of the above, and a driving backboard 200 electrically connected with the display substrate 100.

[0123] In the specific implementation process, the display of the display substrate 100 can be controlled by the driving backboard 200, thereby ensuring the display capability of the display device.

[0124] In addition, the display device solves the problem in a similar way to the aforementioned display substrate, so the implementation of the display device can refer to the implementation of the aforementioned display substrate, and the repeated parts will not be repeated here.

[0125] In the embodiments of the present disclosure, along the direction in which the display substrate 100 points to the driving back plate 200, each of the micro light emitting units 10 comprises an N-type gallium nitride layer 971, a quantum well layer 972, and a P-type gallium nitride layer 973; the P-type gallium nitride is provided with a transparent electrode layer 300 (which can be the aforementioned ITO electrode layer 98) on the side of the light emitting surface of the micro light emitting unit 10, the transparent electrode layer 300 is electrically connected with a first connecting electrode 400 (which can be the aforementioned P Pad 991), and the part of the N-type gallium nitride that does not overlap with the P-type gallium nitride layer 973 is electrically connected with a second connecting electrode 500 (which can be the aforementioned N Pad 990); each of the micro light emitting units 10 is electrically connected with the driving back plate 200 through the corresponding first connecting electrode 400 and the second connecting electrode 500. In this way, the light emitting chip and the driving back plate 200 are electrically connected in a flip-chip manner. In this way, the display substrate 100 ensures the convenience of subsequent packaging, improves the light emitting efficiency and heat dissipation capacity. In the specific implementation process, the display device provided by the embodiments of the present disclosure can be any product or component with display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a digital photo frame, a navigator, etc. The other essential components of the display device should be understood by those skilled in the art, and will not be described here in detail, nor should it be regarded as a limitation on the present disclosure.

[0126] Based on the same disclosure concept, as shown in FIG. 14, the embodiments of the present disclosure also provide a manufacturing method of a display substrate 100, which comprises:

[0127] S101: forming a plurality of light emitting sub-pixels arranged in an array, each of the light emitting sub-pixels comprising a micro light emitting unit;

[0128] S102: forming a color conversion unit on the side of the light emitting surface of the micro light emitting unit corresponding to at least part of the light emitting sub-pixels; wherein the color conversion unit comprises a plurality of nanometer columns arranged in an array, each of the nanometer columns comprising a multi-quantum well structure.

[0129] In the embodiments of the present disclosure, the color conversion unit 20 can be prepared in the following ways, but is not limited thereto.

[0130] In one of the exemplary embodiments, as shown in FIG. 15, step S102: forming a color conversion unit on the side of the light emitting surface of the micro light emitting unit corresponding to at least part of the light emitting sub-pixels, comprises:

[0131] S201: growing a buffer layer on a substrate;

[0132] S202: growing a whole layer of multi-quantum well structure on the buffer layer;

[0133] S203: depositing a mask layer and a nanoimprint glue on the side of the multi-quantum well structure away from the buffer layer in sequence;

[0134] S204: patterning the nanoimprint glue by a nanoimprint process to form a patterned nanoimprint glue;

[0135] S205: etching the mask layer and the multi-quantum well structure according to the patterned nanoimprint glue to form the plurality of nanocolumns arranged in an array;

[0136] S206: removing the mask layer and the nanoimprint glue;

[0137] S207: bonding the plurality of nanocolumns to the light-out surface side of the micro light-emitting unit corresponding to at least part of the light-emitting sub-pixels to form a color conversion unit comprising the plurality of nanocolumns, and removing the substrate and thinning the buffer layer.

[0138] In the implementation process, when preparing the display substrate 100 as shown in FIG. 2, the process flow corresponding to the method step flow shown in FIG. 15 can refer to the process flow shown in FIGS. 8-12, which will not be described here.

[0139] In one example embodiment, as shown in FIG. 16, step S102: forming a color conversion unit on the light-out surface side of the micro light-emitting unit corresponding to at least part of the light-emitting sub-pixels, comprises:

[0140] S301: growing a buffer layer on a substrate;

[0141] S302: depositing a mask layer on the side of the buffer layer away from the substrate;

[0142] S303: patterning the mask layer to obtain a patterned mask layer;

[0143] S304: growing a multi-quantum well structure in a corresponding region according to the patterned mask layer to form a plurality of nanocolumns arranged in an array;

[0144] S305: etching away the patterned mask layer;

[0145] S306: bonding the plurality of nanocolumns to the light-out surface side of the micro light-emitting unit corresponding to at least part of the light-emitting sub-pixels to form a color conversion unit comprising the plurality of nanocolumns, and removing the substrate and thinning the buffer layer.

[0146] In the implementation process, the process flowchart shown in Figure 17 can be used to prepare the display substrate 100 shown in Figure 2, and the implementation process of steps S301 to S306 is explained in detail.

[0147] First, a buffer layer 41 is grown on a substrate; then, a mask layer 43 is deposited on the side of the buffer layer 41 away from the substrate. For example, the substrate can be a sapphire substrate 95, the buffer layer 41 can be a gallium nitride buffer layer 41, and the mask layer 43 can be SiO2; then, the mask layer 43 is patterned to remove the mask layer 43 in the selected area for epitaxy; then, according to the patterned mask layer 43, the InGaN / GaN multi-quantum well structure 42 with the required diameter is grown in the corresponding area to form a plurality of nanorods 30 arranged in an array; then, the patterned mask layer 43 is etched to obtain the color conversion unit 20 including a plurality of nanorods 30.

[0148] It should be noted that one of the schemes shown in Figures 8 to 12 can be used to prepare a single color conversion chip as shown in Figure 2, and the full-color display of the display device is realized by mass transfer. Another scheme can also be used, and the blue light color conversion process flowchart shown in Figure 18 is used to first complete the electrical connection between the micro light emitting unit 10 array and the driving backboard 200. For example, the electrical connection between the micro light emitting unit 10 array and the driving backboard 200 can be realized by metal alignment bonding; the electrical connection between the micro light emitting unit 10 array and the driving backboard 200 can also be realized by using the method of brushing tin paste and die bonding.

[0149] Specifically, the corresponding specific process steps of FIG. 18 can be S1: preparing the first distributed Bragg reflector 80 on the micro light emitting unit 10 array; S2: preparing the first bonding layer 92; for example, prepared by spin coating, specifically, the transparent adhesive material bonding can be used, the bonding force is greater than 0.05N, and the light transmittance is greater than 95%; S3: green color conversion unit bonding and patterning; the related process can refer to FIG. 11. The green color conversion unit can be bonded with the micro light emitting unit 10 array through the first bonding layer 92, and the bonding process is carried out under a certain pressure and temperature. Generally, the bonding pressure is 4000N-15000N, and the specific temperature value can be set according to the requirements of the adhesive material. Generally, the temperature value does not exceed 300°C. After bonding, the sapphire substrate 95 and the buffer layer 41 are removed. For example, the LLO is used to remove the sapphire substrate 95, and the ICP etching is used to thin the buffer layer 41; then, the photolithography process is used to form a patterned protection, and finally the ICP etching is used to realize the patterning of the green color conversion unit 2060. S4: red color conversion unit 2070 bonding and patterning; the bonding between the red color conversion unit 2070 and the micro light emitting unit 10 array can be realized through the second bonding layer 93; the specific preparation process is the same as that of the green color conversion unit 2060 bonding and patterning, which will not be repeated here. S5: preparing the anti-crosstalk layer 91; for example, the anti-crosstalk layer 91 can be a black barrier, a gray barrier or a white barrier, which is not limited here. For example, the second distributed Bragg reflector 90 can be set on the second bonding layer 93. The related structural parameters of the second distributed Bragg reflector 90 can refer to the description in the foregoing related part, which will not be repeated here. It should be noted that in the example embodiment shown in FIG. 18, each micro light emitting unit 10 is a blue light emitting device capable of emitting blue light, so that the preparation of the display device for realizing full-color display by combining the blue light emitting device with the color conversion unit 20 is realized.

[0150] Another scheme can also be used. According to the violet light color conversion process flow chart shown in FIG. 19, the electrical connection between the micro light emitting unit 10 array and the driving backboard 200 is first completed. For example, the electrical connection between the micro light emitting unit 10 array and the driving backboard 200 can be realized by metal alignment bonding; the electrical connection between the micro light emitting unit 10 array and the driving backboard 200 can also be realized by using the tin paste brushing, die bonding and piece making. Then, the driving backboard 200 can realize the driving and lighting of the corresponding micro light emitting unit 10 array.

[0151] In the exemplary embodiment shown in FIG. 19, each micro light emitting unit 10 can be an ultraviolet light emitting device for emitting ultraviolet light, because the color conversion unit 20 has stronger absorption of ultraviolet light. The ultraviolet color conversion scheme shown in FIG. 19 is substantially similar to the blue light color conversion scheme shown in FIG. 18, except that the ultraviolet color conversion scheme adds the preparation of the blue light color conversion unit 2050, and the preparation process of the entire display device needs to be performed three times. The specific preparation process can be referred to the description of the foregoing related parts, which will not be described here.

[0152] It should be noted that the light emitting chip in the embodiment of the present disclosure can also be applied to a three-in-one chip to realize full-color display. The related process flow chart can refer to the three-in-one blue light chip process flow chart shown in FIG. 20 and the three-in-one full-color display preparation process flow chart shown in FIG. 21.

[0153] In the process flow chart shown in FIG. 20, (1) P electrode preparation and sub-pixel segmentation; the P electrode can be ITO, and the thickness can be about 120 nm. Exemplarily, the sub-pixel segmentation can be realized by etching, and in actual application, different designs can be made according to the size of the sub-pixel; in one exemplary embodiment, the thickness of the ITO electrode layer 98 can be 0.06 μm, the thickness of the P-type gallium nitride layer 973 can be 0.2 μm, the thickness of the quantum well layer 972 can be 0.05 μm, the thickness of the N-type gallium nitride layer 971 can be 2 μm, and the thickness of the buffer layer 41 gallium nitride 96 can be 2 μm. Of course, the specific thickness values of the ITO layer, the P-type gallium nitride layer 973, the quantum well layer 972, the N-type gallium nitride layer 971 and the buffer layer 41 gallium nitride 96 can also be set according to actual application needs, which are not limited here. (2) Deep etching; the etching can be performed to the thickness range of 4 μm to 5 μm of the sapphire substrate 95, the N-type gallium nitride layer 971 and the buffer layer 41 gallium nitride 96 according to the size of the chip. (3) Preparation of cathode metal electrode (i.e. N electrode 99); exemplarily, the cathode metal electrode can be Ti / Al / Ni / Au or Cr / Pt / Au, and the preparation area can be as shown in the figure, and the thickness is about 1 μm. (4) Preparation of passivation layer 992 and electrode opening; exemplarily, the passivation layer 992 can be SiO or SiN structure, and the thickness range can be 500 μm to 1000 μm, and the electrode opening can be prepared by photolithography and etching scheme. (5) Preparation of P Pad 991; Ti / Al / Ni / Au can be used, which is similar to the preparation scheme of the N electrode 99, and will not be described here. (6) Preparation of N Pad 990; the preparation of N Pad 990 is similar to the preparation of P Pad 991, which will not be described here.

[0154] In the process flowchart shown in FIG. 21, ①: temporary bonding; the three-in-one blue light emitting (Cow) chip can be bonded to a temporary substrate (i.e., temporary carrier 600) such as glass or sapphire by using temporary bonding. ②: removing sapphire substrate 95; the original sapphire substrate 95 can be removed by using LLO to expose the light emitting surface, and the gallium nitride buffer layer 41 can be removed by using ICP to thin the chip as a whole. ③: bonding and patterning of green light color conversion unit 2060; the specific preparation process can be referred to the description of the related parts described above, and will not be repeated here. ④: bonding and patterning of red light color conversion unit 2070, similar to the description of the related parts described above, and will not be repeated here. ⑤: preparation of anti-crosstalk layer 91; the specific preparation process of the anti-crosstalk layer 91 can be referred to the description of the related parts described above, and will not be repeated here. ⑥: preparation of first distributed Bragg reflector 80; the first distributed Bragg reflector 80 is used to transmit red and green light and reflect blue light, thereby increasing the utilization rate of blue light and improving light extraction. The specific structure of the first distributed Bragg reflector 80 can be referred to the description of the related parts described above, and will not be repeated here. ⑦: removing temporary carrier 600; the temporary carrier 600 can be removed by using LLO, and the electrode structure (N Pad 990 and P Pad 991) is exposed by ashing the residual glue. ⑧: chip cutting; for example, the chip can be cut into a single independent structure by using laser cutting. ⑨: die bonding; for example, the die bonding and electrical connection with the driving backboard 200 can be achieved by using tin paste or soldering flux, pick (pick) & place, thereby providing a guarantee for full-color display of the display device.

[0155] It should be noted that in the process flowcharts shown in FIGS. 20 and 21, the top view structure of the part of the film layer corresponding to the cross-sectional structure is also shown. Of course, in the embodiments of the present disclosure, the light emitting chip can be a blue light emitting device, and an ultraviolet light emitting device for emitting ultraviolet light, and other light emitting devices of other light emitting colors can also be provided according to actual application needs. In addition, the display device and the display substrate 100 in the embodiments of the present disclosure can also include other film layer structures, and the specific settings can be referred to the description of the related parts, and will not be described in detail here. In the embodiments of the present disclosure, unless otherwise specified, the cross-sectional shape of the micro light emitting unit 10 is not limited to the trapezoidal structure in the related drawings, and in the actual preparation process, the cross-sectional shape of the micro light emitting unit 10 is set as an approximately rectangular structure, and of course, the cross-sectional shape of the micro light emitting unit 10 can also be set according to actual application needs, which is not limited here.

[0156] While the preferred embodiments of the disclosure have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure. Therefore, it is intended that the appended claims shall cover all such modifications and variations as fall within the true spirit and scope of the disclosure. Accordingly, the specification is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the disclosure. It is to be understood that the forms of the disclosure herein shown and described are to be taken only as illustrative and not as restrictive.

[0157] Obviously, many modifications and variations of the present disclosure are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the disclosure can be practiced otherwise than as specifically described.

Claims

1. A display substrate, wherein, include: Multiple light-emitting sub-pixels arranged in an array; Each of the light-emitting sub-pixels includes a micro-light-emitting unit, and at least some of the light-emitting sub-pixels include a color conversion unit located on one side of the light-emitting surface of the corresponding micro-light-emitting unit; the color conversion unit includes a plurality of nanopillars arranged in an array, and each nanopillar includes a multi-quantum-well structure.

2. The display substrate as claimed in claim 1, wherein, Along the cross-sectional direction parallel to the plane where the micro-luminescent unit is located, the extension lengths of each of the nanopillars corresponding to the luminescent sub-pixels of the same luminescent color in at least a portion of the luminescent sub-pixels are equal.

3. The display substrate as described in claim 1, wherein, Within the same light-emitting sub-pixel, along the direction from the color conversion unit to the micro-light-emitting unit, the cross-sectional area of ​​each nanopillar along the plane parallel to the micro-light-emitting unit increases.

4. The display substrate as claimed in claim 1, wherein, Each of the plurality of light-emitting sub-pixels has a color conversion unit on one side of the light-emitting surface of the micro-light-emitting unit corresponding to the light-emitting sub-pixel, and the color conversion units do not overlap with each other.

5. The display substrate as claimed in claim 4, wherein, All the color conversion units are set to the same layer and material.

6. The display substrate as claimed in claim 4, wherein, The color conversion units corresponding to the various light-emitting sub-pixels of the plurality of light-emitting sub-pixels are made of the same material, the color conversion units corresponding to the light-emitting sub-pixels of the same light-emitting color of the plurality of light-emitting sub-pixels are set in the same layer, and the color conversion units corresponding to the light-emitting sub-pixels of different light-emitting colors of the plurality of light-emitting sub-pixels are set in different layers.

7. The display substrate as claimed in claim 6, wherein, The plurality of light-emitting sub-pixels include blue light sub-pixels, green light sub-pixels, and red light sub-pixels; the blue sub-pixel includes a blue light conversion unit located on the side opposite to the light-emitting surface of the corresponding micro-light-emitting unit, the green sub-pixel includes a green light conversion unit located on the side opposite to the light-emitting surface of the corresponding micro-light-emitting unit, and the red sub-pixel includes a red light conversion unit located on the side opposite to the light-emitting surface of the corresponding micro-light-emitting unit, and the blue light conversion unit, the green light conversion unit, and the red light conversion unit are arranged sequentially on the side opposite to the light-emitting surface of the micro-light-emitting unit.

8. The display substrate as claimed in claim 7, wherein, Along a direction parallel to the color conversion unit pointing towards the micro-light-emitting unit, the red light color conversion unit, the green light color conversion unit, and the blue light color conversion unit all have a decreasing cross-sectional area along the plane parallel to the micro-light-emitting unit.

9. The display substrate as claimed in claim 1, wherein, The plurality of light-emitting sub-pixels include blue sub-pixels, green sub-pixels, and red sub-pixels, and each of the micro-light-emitting units is a blue light-emitting device capable of emitting blue light, and only the green sub-pixels and the red sub-pixels are provided with color conversion units corresponding to the corresponding micro-light-emitting units; the green sub-pixel includes a green light color conversion unit located on the side opposite to the light-emitting surface of the corresponding micro-light-emitting unit, and the red sub-pixel includes a red light color conversion unit located on the side opposite to the light-emitting surface of the corresponding micro-light-emitting unit, and the green light color conversion unit and the red light color conversion unit are arranged sequentially on the side opposite to the light-emitting surface of the micro-light-emitting unit.

10. The display substrate according to any one of claims 1-9, wherein, It also includes a first distributed Bragg reflector located on one side of the light-emitting surface of each of the micro-light-emitting units, the first distributed Bragg reflector being configured to transmit blue light and reflect red and green light.

11. The display substrate according to any one of claims 7-9, wherein, It also includes a second distributed Bragg reflector located on the side of the red light conversion unit away from the micro-light-emitting unit, the second distributed Bragg reflector being configured to transmit red and green light and reflect blue light.

12. The display substrate according to any one of claims 1-9, wherein, It also includes an anti-crosstalk layer disposed around each of the micro-light-emitting units, the anti-crosstalk layer and the color conversion unit not overlapping each other.

13. A light-emitting chip, wherein, include: Micro-light-emitting unit and color conversion unit located on one side of the light-emitting surface of the micro-light-emitting unit; The color conversion unit comprises an array of multiple nanopillars, each of which comprises a multi-quantum well structure.

14. The light-emitting chip as described in claim 13, wherein, Along the direction from the color conversion unit to the micro-luminescent unit, the cross-sectional area of ​​each nanopillar increases along the plane parallel to the micro-luminescent unit.

15. The light-emitting chip as described in claim 13 or 14, wherein, It also includes a distributed Bragg reflector located between the micro-light-emitting unit and the color conversion unit, the distributed Bragg reflector completely covering the micro-light-emitting unit.

16. The light-emitting chip as described in claim 15, wherein, It also includes a first bonding unit located between the distributed Bragg reflector and the color conversion unit, a second bonding unit disposed at least around each of the nanopillars, and a substrate located on the side of the plurality of nanopillars and the second bonding unit facing away from the light-emitting surface of the micro-luminescent unit.

17. A display device, wherein, include: The display substrate as described in any one of claims 1-12, and the driving backplate electrically connected to the display substrate.

18. The display device as claimed in claim 17, wherein, Along the direction from the display substrate to the driving backplate, each of the micro-light-emitting units includes an N-type gallium nitride layer, a quantum well layer, and a P-type gallium nitride layer; a transparent electrode layer is disposed on the side of the P-type gallium nitride layer opposite to the light-emitting surface of the micro-light-emitting unit, and the transparent electrode layer is electrically connected to a first connecting electrode; the portion of the N-type gallium nitride layer that does not overlap with the P-type gallium nitride layer is electrically connected to a second connecting electrode; each of the micro-light-emitting units is electrically connected to the driving backplate through the corresponding first connecting electrode and second connecting electrode.

19. A method for manufacturing a display substrate, wherein, include: Multiple light-emitting sub-pixels are formed in an array, each of which includes a micro-light-emitting unit; A color conversion unit is formed on the light-emitting surface side of the micro-light-emitting unit corresponding to at least some of the plurality of light-emitting sub-pixels; wherein, the color conversion unit includes a plurality of nanopillars arranged in an array, and each nanopillar includes a multi-quantum-well structure.

20. The method of claim 19, wherein, A color conversion unit is formed on one side of the light-emitting surface of the micro-light-emitting unit corresponding to at least some of the plurality of light-emitting sub-pixels, including: A buffer layer is grown on the substrate; A full-layer multi-quantum-well structure is grown on the buffer layer; On the side of the multi-quantum-well structure opposite to the buffer layer, a mask layer and a nanoimprint adhesive are sequentially deposited; The nanoimprint adhesive is patterned using a nanoimprinting process to form a patterned nanoimprint adhesive. The mask layer and the multiple quantum well structure are etched according to the patterned nanoimprint adhesive to form the multiple nanopillars arranged in an array. Remove the mask layer and the nanoimprint adhesive; The plurality of nanopillars are bonded to the light-emitting side of the micro-light-emitting unit corresponding to at least some of the light-emitting sub-pixels to form a color conversion unit including the plurality of nanopillars, and the substrate is removed and the buffer layer is thinned.

Images