Miniature light emitting diode display chip, preparation method and display device

Abstract

The invention discloses a micro light-emitting diode display chip, a preparation method and a display device, and the chip comprises a driving substrate which comprises a plurality of contacts; the multiple display screens are arranged on the driving substrate at intervals, and the multiple display screens are located on the same plane; the display screen comprises a plurality of LED units arranged in an array, the LED units are used for emitting light of a first color, and the LED units are independently driven through corresponding contacts; the wavelength conversion layer is arranged on the side, away from the driving substrate, of the display screen. In the display chip, the plurality of display screens located on the same plane are arranged on the driving substrate, the whole screen uses the same basic primary color, then full-color display of the whole chip can be completed by using a quantum dot process, and due to the fact that the whole surface is the same basic primary color, the bonding yield of the LED unit 201 is greatly improved.

Description

Technical Field

[0001] The present application belongs to the field of micro-display technology, and specifically relates to a micro light emitting diode display chip, a preparation method, and a display device. Background Art

[0002] In order to realize color projection, the three-color light combination technology that uses red, green and blue light sources to synthesize color images has come into being. This technology allows the use of three independent light sources to control the color and brightness of each pixel, so it has the advantages of high resolution and high brightness. Micro-light emitting diode display chips not only have the characteristics of small size, but also have the advantages of high brightness, low power consumption, fast response, long life, and high light efficiency. They can be used as light sources for color projection, but in the light combination process, each independent light source is required to be precisely aligned in time and space so that they can be combined into a seamless color image. However, there is an alignment deviation of the independent light sources, which may cause problems such as color misalignment, blur or artifacts in the image. Summary of the invention

[0003] Purpose of the invention: The purpose of this application is to provide.

[0004] Technical solution: To achieve the above-mentioned invention object, the present application provides a micro light emitting diode display chip, comprising:

[0005] A driving substrate, wherein the driving substrate comprises a plurality of contacts;

[0006] A plurality of display screens, the plurality of display screens are arranged on the driving substrate at intervals, and the plurality of display screens are located in the same plane; the display screens include a plurality of LED units arranged in an array, the LED units are used to emit light of a first color, and the LED units are driven individually through the corresponding contacts;

[0007] A wavelength conversion layer, wherein the wavelength conversion layer is arranged on a side of the display screen away from the driving substrate; the wavelength conversion layer comprises a first wavelength conversion unit and a second wavelength conversion unit; the first wavelength conversion unit is arranged correspondingly with all the LED units in one of the display screens to form a first display module, and the first wavelength conversion unit can convert the first color light into a second color light; the second wavelength conversion unit is arranged correspondingly with all the LED units in another of the display screens to form a second display module, and the second wavelength conversion unit can convert the first color light into a third color light.

[0008] In some embodiments, the wavelength conversion layer further includes a third wavelength conversion unit, and the third wavelength conversion unit is arranged corresponding to all the LED units in another display screen to form a third display module, and the third wavelength conversion unit can convert the first color light into a fourth color light.

[0009] In some embodiments, the display screen further comprises:

[0010] A grid layer, wherein the grid layer is located on a surface of the driving substrate facing the wavelength conversion layer; the grid layer has a plurality of grid holes corresponding to the LED units, and the LED units are arranged in the corresponding grid holes; the first wavelength conversion unit, the second wavelength conversion unit, and the third wavelength conversion unit are filled in the grid holes.

[0011] In some embodiments, the display screen further comprises:

[0012] A bonding layer, wherein the bonding layer is disposed between the driving substrate and the LED unit, and the LED unit is electrically connected to the bonding layer;

[0013] A reflective layer, wherein the reflective layer at least covers the side walls of the grid holes.

[0014] In some embodiments, the display screen further comprises:

[0015] A passivation layer, the passivation layer covering the side surfaces of the LED unit;

[0016] An electrode layer, the electrode layer covers a side of the passivation layer away from the LED unit, the electrode layer is electrically connected to the driving substrate and the top surface of the LED unit respectively; the passivation layer electrically isolates the electrode layer from the LED unit; the passivation layer also covers a side wall of the bonding layer and electrically isolates the electrode layer from the bonding layer;

[0017] An etching blocking layer, wherein the etching blocking layer is located on a surface of the electrode layer facing the wavelength conversion layer; the electrode layer also has a light emitting hole exposing the LED unit, the etching blocking layer fills the light emitting hole and covers the top surface of the LED unit; the etching blocking layer is located between the reflective layer and the electrode layer, and electrically isolates the reflective layer and the electrode layer.

[0018] In some embodiments, the reflective layer also covers a surface of the grid layer away from the driving substrate, and a surface of the reflective layer away from the grid layer is flush with a surface of the wavelength conversion layer away from the display screen.

[0019] In some embodiments, it also includes:

[0020] A first filter layer, the first filter layer is located on a surface of the first wavelength conversion unit away from the LED unit, and the first filter layer is used to filter other color lights and allow the second color light to pass through;

[0021] a second filter layer, the second filter layer being located on a surface of the second wavelength conversion unit at a side away from the LED unit, the second filter layer being used for filtering other color lights and allowing the third color light to pass through;

[0022] A third filter layer is located on a surface of the third wavelength conversion unit at a side away from the LED unit, and is used for filtering other color lights and allowing the fourth color light to pass through.

[0023] In some embodiments, the LED unit is a step structure, which includes a first doped semiconductor layer, a second doped semiconductor layer and an active layer located therebetween; the step structure disconnects and electrically isolates the adjacent second doped semiconductor layer, the active layer and the first doped semiconductor layer from each other; the contact is electrically connected to the corresponding first doped semiconductor layer.

[0024] In some embodiments, the size of the LED unit is 0.1-10 μm; or

[0025] The driving substrate is a silicon-based CMOS driving board or a thin film field effect transistor driving board.

[0026] In some embodiments, the present application also provides a method for preparing a micro light emitting diode display chip, comprising:

[0027] providing a driving substrate, the driving substrate comprising a plurality of contacts;

[0028] forming an LED epitaxial layer on the driving substrate;

[0029] The LED epitaxial layer is separated into a plurality of processing areas, and the LED epitaxial layer in each processing area is etched to form a display screen, wherein the plurality of display screens are located in the same plane; the display screen comprises a plurality of LED units arranged in an array, wherein the LED units are used to emit light of a first color; and the LED units are driven individually through the corresponding contacts;

[0030] A wavelength conversion layer is formed on a side of the display screen away from the driving substrate, and the wavelength conversion layer includes a first wavelength conversion unit and a second wavelength conversion unit; the first wavelength conversion unit is correspondingly arranged on all the LED units in one display screen to form a first display module, and the first wavelength conversion unit can convert the first color light into a second color light; the second wavelength conversion unit is correspondingly arranged on all the LED units in another display screen to form a second display module, and the second wavelength conversion unit can convert the first color light into a third color light.

[0031] In some embodiments, the wavelength conversion layer also includes a third wavelength conversion unit; the third wavelength conversion unit is correspondingly arranged on all the LED units in another display screen to form a third display module, and the third wavelength conversion unit can convert the first color light into a fourth color light.

[0032] In some embodiments, the step of forming the LED epitaxial layer on the driving substrate further includes:

[0033] Providing a substrate having an LED epitaxial layer on the substrate; forming a bonding layer on the driving substrate and / or the LED epitaxial layer; bonding the driving substrate and the LED epitaxial layer through the bonding layer; and removing the substrate.

[0034] In some embodiments, the step of etching the LED epitaxial layer of each processing area to form a display screen is:

[0035] Etching the LED epitaxial layer to form a plurality of LED units, wherein the LED unit array is arranged on the bonding layer;

[0036] A grid layer is formed on a surface of the driving substrate facing the display screen, a plurality of grid holes corresponding to the LED units are formed on the grid layer, and a plurality of the LED units are arranged in the corresponding grid holes;

[0037] A reflective layer is formed on the sidewalls of the grid holes and on the surface of the grid layer at a side away from the driving substrate.

[0038] In some embodiments, the step of etching the LED epitaxial layer of each processing area to form a display screen further includes: forming a passivation layer on the side surface of the first LED unit and the side surface of the bonding layer;

[0039] An electrode layer is formed on a side of the passivation layer away from the LED unit, the electrode layer is electrically connected to the corresponding contact points and the top surface of the LED unit, and the passivation layer electrically isolates the electrode layer from any one of the LED unit and the bonding layer;

[0040] A light emitting hole is formed at a position of the electrode layer corresponding to the top surface of the LED unit, and an etching blocking layer is formed on the surface of the electrode layer away from the driving substrate; the etching blocking layer fills the light emitting hole and covers the electrode layer and the top surface of the LED unit; the etching blocking layer is located between the light reflecting layer and the electrode layer, and the etching blocking layer electrically isolates the light reflecting layer and the electrode layer.

[0041] In some embodiments, the step of forming the wavelength conversion layer further comprises:

[0042] Filling a first wavelength conversion unit in all grid holes of a grid layer of the display screen; and / or

[0043] Filling a second wavelength conversion unit in all grid holes of the grid layer of another display screen; and / or

[0044] Filling a third wavelength conversion unit in all grid holes of the grid layer of another display screen;

[0045] Wherein, any of the display screens emits light of one color.

[0046] In some embodiments, after the step of forming the wavelength conversion layer, the method further includes:

[0047] A first filter layer is formed on a surface of the first wavelength conversion unit away from the LED unit, wherein the first filter layer is used to filter other color lights and allow the second color light to pass through;

[0048] A second filter layer is formed on a surface of the second wavelength conversion unit away from the LED unit, wherein the second filter layer is used to filter other color lights and allow the third color light to pass through;

[0049] A third filter layer is formed on a surface of the third wavelength conversion unit at a side away from the LED unit, and the third filter layer is used to filter other color lights and allow the fourth color light to pass through.

[0050] In some embodiments, the present application also provides a display device, including the micro-light emitting diode display chip; or, including the micro-light emitting diode display chip prepared by the method described.

[0051] In some embodiments, the light emitting direction of the display screen is a first direction, the direction in which the plurality of display screens are arranged at intervals is a second direction, and the first direction intersects with the second direction; the display device further includes:

[0052] A light combining module, the light combining module comprising a first light combining unit and a second light combining unit located in the same plane and spaced apart along the second direction; the first light combining unit and the first display module are arranged correspondingly in the first direction, and the first light combining unit is used to convert the second color light from the first direction to emit in the second direction; the second light combining unit and the second display module are arranged correspondingly in the first direction, and the second light combining unit is used to convert the third color light from the first direction to emit in the second direction, and allows the second color light emitted in the second direction to pass through.

[0053] In some embodiments, the light combining module further includes a third light combining unit, the third light combining unit, the first light combining unit, and the second light combining unit are located in the same plane, and the third light combining unit is arranged on a side of the second light combining unit away from the first light combining unit along the second direction;

[0054] The third light combining unit and the third display module are correspondingly arranged in the first direction, and the third light combining unit is used to convert the fourth color light from the first direction to emit in the second direction, and to allow any one of the second color light and the third color light emitted in the second direction to pass through.

[0055] In some embodiments, the first light-combining unit has a first optical film facing the first display module, and the orthographic projection of the first optical film on the driving substrate along the first direction covers the first display module; the second light-combining unit has a second optical film facing the second display module, and the orthographic projection of the second optical film on the driving substrate along the first direction covers the second display module; the third light-combining unit has a third optical film facing the third display module, and the orthographic projection of the third optical film on the driving substrate along the first direction covers the third display module.

[0056] In some embodiments, any one of the first optical film, the second optical film, and the third optical film is inclined relative to the surface of the driving substrate, and the inclination angle is adjusted according to the requirements of the light-emitting surface, and the first optical film, the second optical film, and the third optical film are arranged parallel to each other to ensure that light from different light-emitting modules can overlap on the light-emitting surface.

[0057] In some embodiments, the first and second doped semiconductor layers may include one or more layers based on IIVI materials such as ZnSe or ZnO or IIIV nitride materials such as GaN, AlN, InN, InGaN, GaP, AlInGaP, AlGaAs and alloys thereof.

[0058] In some embodiments, the first doped semiconductor layer is a p-type semiconductor layer, and the second doped semiconductor layer is an n-type semiconductor layer.

[0059] In some embodiments, an active layer is further provided between the first doped semiconductor layer and the second doped semiconductor layer. The active layer may specifically be a multi-quantum well structure for confining electron and hole carriers to the quantum well region. When electrons and holes recombine, the carriers undergo radiative recombination and emit photons, thereby converting electrical energy into light energy.

[0060] Beneficial effects: Compared with the prior art, the micro-light emitting diode display chip of the present application includes: a driving substrate, the driving substrate includes multiple contacts; multiple display screens, the multiple display screens are arranged on the driving substrate at intervals, and the multiple display screens are located in the same plane; the display screen includes multiple LED units arranged in an array, the LED units are used to emit light of a first color, and the LED units are driven individually through corresponding contacts; a wavelength conversion layer, the wavelength conversion layer is arranged on the side of the display screen away from the driving substrate; the wavelength conversion layer includes a first wavelength conversion unit and a second wavelength conversion unit; the first wavelength conversion unit is correspondingly arranged with all the LED units in a display screen to form a first display module, and the first wavelength conversion unit can convert the first color light into the second color light; the second wavelength conversion unit is correspondingly arranged with all the LED units in another display screen to form a second display module, and the second wavelength conversion unit can convert the first color light into the third color light. In the display chip of the present application, multiple display screens located in the same plane are arranged on the driving substrate, and the entire screen uses the same basic primary color. Then, the quantum dot process is used to complete the full-color display of the entire chip. Since the entire surface is the same basic primary color, only one semiconductor layer bonding and substrate peeling are required, thus avoiding the yield reduction caused by multiple semiconductor layer bonding and substrate peeling.

[0061] The present application discloses a method for preparing a micro light emitting diode display chip, comprising: providing a driving substrate, the driving substrate comprising a plurality of contacts; forming an LED epitaxial layer on the driving substrate, and removing the substrate; separating the LED epitaxial layer into a plurality of processing areas, etching the LED epitaxial layer in each processing area to form a display screen, wherein the plurality of display screens are located in the same plane; the display screen comprises a plurality of LED units arranged in an array, the LED units being used to emit light of a first color; and the LED units being driven individually through corresponding contacts; forming a wavelength conversion layer on a side of the display screen away from the driving substrate, the wavelength conversion layer comprising a first wavelength conversion unit and a second wavelength conversion unit; correspondingly arranging the first wavelength conversion unit on all the LED units in one display screen to form a first display module, the first wavelength conversion unit being capable of converting the first color light into the second color light; correspondingly arranging the second wavelength conversion unit on all the LED units in another display screen to form a second display module, the second wavelength conversion unit being capable of converting the first color light into the third color light. The method of the present application can realize the preparation of multiple display screens on the same plane by separating multiple processing areas on the driving substrate. The highly integrated LED unit can improve the compactness and space utilization of the chip, and complete the design of the display module through the combination of wavelength conversion layers, realizing the chip's multi-color display and improving the color display capability of the display chip.

[0062] The present application also provides a display device, including a micro-light emitting diode display chip and a light combining module, the light emitting direction of the display screen is a first direction, the direction in which multiple display screens are arranged at intervals is a second direction, and the first direction intersects with the second direction; the light combining module includes a first light combining unit and a second light combining unit located in the same plane and arranged at intervals along the second direction; the first light combining unit and a display screen are arranged correspondingly in the first direction, and the first light combining unit is used to convert the second color light from the first direction to be emitted in the second direction; the second light combining unit and another display screen are arranged correspondingly in the second direction, and the second light combining unit is used to convert the third color light from the first direction to be emitted in the second direction, and allow the second color light emitted in the second direction to pass through. The display device of the present application arranges display modules emitting light of different colors on the same driving substrate, so that the light output of the display modules is aligned on the surface along the second direction. It is only necessary to adjust the angle and the front-to-back distance of the first light combining unit and the second light combining unit to complete the light combining of multiple colors. Compared with the light combining structure of multiple independent display chips through a prism, the alignment difficulty of the present application is greatly improved, and the structure and process of the light combining module are simpler, the production efficiency is significantly improved, and it has a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The technical solutions and other beneficial effects of the present invention will be made apparent by describing in detail the specific embodiments of the present invention in conjunction with the accompanying drawings.

[0064] Figure 1 A schematic diagram of a partial cross-sectional structure of a micro light emitting diode display chip of the present application is shown;

[0065] Figure 2 A schematic diagram of the structure of the driving substrate provided by the present application is shown;

[0066] Figure 3 Shows Figure 2 The cross-sectional view along the AA direction;

[0067] Figure 4 A schematic diagram of the structure of the substrate and LED epitaxial layer provided by the present application is shown;

[0068] Figure 5 A schematic diagram showing a bonding process between a substrate and a driving substrate in an embodiment of the present application is shown;

[0069] Figure 6 A schematic diagram showing a process area set on an LED epitaxial layer in an embodiment of the present application is shown;

[0070] Figure 7 Shows Figure 6 A top view of the structure;

[0071] Figure 8A schematic diagram showing the formation of LED units in a processing area in an embodiment of the present application is shown;

[0072] Fig. 9 A schematic diagram showing the formation of an etching stop layer, a grid layer and a reflective layer in an embodiment of the present application is shown;

[0073] Fig.10 Shows Figure 1 A top view of the structure;

[0074] Fig.11 A schematic diagram of the structure of a display device provided in an embodiment of the present application is shown;

[0075] Fig.12 A schematic diagram of the light combining principle of a display device is shown;

[0076] Figure numerals: 10-driving substrate, 102-contact, 101-common contact, 20-display screen, 201-LED unit, 2011-first doped semiconductor layer, 2012-second doped semiconductor layer, 2013-active layer, 202-grid layer, 2021-grid hole, 203-passivation layer, 204-electrode layer, 2041-light exit hole, 205-reflective layer, 30-wavelength conversion layer, 301-first wavelength conversion unit, 302-second wavelength conversion unit, 303-third Wavelength conversion unit, 40-bonding layer, 50-etching blocking layer, 60-first filter layer, 70-second filter layer, 80-third filter layer, 90-substrate, 901-LED epitaxial layer, 100-first display module, 200-second display module, 300-third display module, 400-processing area, 2-light combining module, 21-first light combining unit, 22-second light combining unit number, 23-third light combining unit, 211-first optical film, 221-second optical film, 231-third optical film. DETAILED DESCRIPTION

[0077] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0078] The disclosure of the present invention provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described in the present invention. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0079] Generally, the terms may be understood at least in part based on the usage of the above invention. For example, the term "one or more" used in the present invention may be used to describe any component, structure or feature in the singular form, or may be used to describe a combination of components, structures or features in the plural form, depending at least in part on the above invention. Similarly, terms such as "one", "an" or "the" may also be understood at least in part to convey singular usage or to convey plural usage depending at least in part on the above invention. In addition, the term "based on..." may be understood to not necessarily be intended to convey a set of exclusive factors, but may instead allow for the presence of additional factors that do not necessarily have to be explicitly described, depending at least in part on the above invention.

[0080] It should be easily understood that the meanings of “on,” “over,” and “on…” in the present invention should be interpreted in the broadest manner, so that “on…” means not only “directly on something,” but also means “on something” including the presence of intermediate components or layers therebetween, and “on something” or “on something” means not only “on something” or “on something,” but also includes the meaning of “on something” or “on something” without any intermediate components or layers therebetween.

[0081] Additionally, for ease of description, spatially relative terms such as "below," "beneath," "lower," "above," "upper," etc. may be used herein to describe the relationship of one element or component to another element or component as shown in the drawings. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the drawings. The device may be otherwise oriented, rotated 90 degrees or at other orientations, and the spatially relative descriptors used herein may likewise be interpreted accordingly.

[0082] The term "layer" used in the present invention refers to a material portion including an area with a certain thickness. The layer can extend over the entire lower or upper structure, or can have a degree less than the scope of the lower or upper structure. In addition, the layer can be a region of a homogeneous or inhomogeneous continuous structure, and its thickness is less than the thickness of the continuous structure. For example, the layer can be located between the top surface and the bottom surface of the continuous structure or between any pair of horizontal planes therebetween. The layer can extend horizontally, vertically and / or along a tapered surface. The substrate can be a layer, one or more layers can be included therein, and / or one or more layers can be provided thereon, above and / or below. A layer can include multiple layers. For example, the semiconductor layer can include one or more doped or undoped semiconductor layers, and can have the same or different materials.

[0083] In some embodiments, the term drive substrate 10 used in this application refers to a material on which subsequent material layers are added. The drive substrate 10 itself can be patterned. The material added to the top of the drive substrate 10 can be patterned or can remain unpatterned. The drive substrate 10 can be, for example, but not limited to, a display substrate including a silicon-based CMOS drive board or a thin film field effect transistor drive board, such as a CMOS (Complementary Metal Oxide Semiconductor) backplane or a TFT glass substrate.

[0084] See also Figure 1 and Fig.10 , provides a micro light emitting diode display chip, comprising: a driving substrate 10, a plurality of display screens 20 and a wavelength conversion layer 30; the driving substrate 10 comprises a plurality of contacts 102; the plurality of display screens 20 are arranged on the driving substrate 10 at intervals, and the plurality of display screens 20 are located in the same plane; the display screen 20 comprises a plurality of LED units 201 arranged in an array, the LED units 201 are used to emit light of a first color, and the LED units 201 are driven individually through corresponding contacts 102; the wavelength conversion layer 30, the wavelength conversion layer 30 is arranged on a side of the display screen 20 away from the driving substrate 10; the wavelength conversion layer 30 comprises a first wavelength conversion unit 301 and a second wavelength conversion unit 302; the first wavelength conversion unit 301 is arranged correspondingly with all the LED units 201 in one display screen 20 to form a first display module 100, and the first wavelength conversion unit 301 can convert the first color light into the second color light; the second wavelength conversion unit 302 is arranged correspondingly with all the LED units 201 in another display screen 20 to form a second display module 200, and the second wavelength conversion unit 302 can convert the first color light into the third color light.

[0085] It can be understood that in the display chip provided by this embodiment, since multiple display screens 20 are located in the same plane on the driving substrate 10, the entire display system is more compact and simplified. When multiple display screens 20 are located in the same plane, the connection and wiring between components can be reduced, the possibility of errors and bad conditions in the bonding process is reduced, and the bonding yield is improved. At the same time, the array arrangement of the display screens 20 also makes the bonding process more regular and consistent, and improves the bonding yield; the entire screen uses the same basic primary color, and then the quantum dot process can complete the full-color display of the entire chip. Since the entire surface is the same basic primary color, the bonding yield of the LED unit 201 is greatly improved. Each LED unit 201 is driven separately through the corresponding contact 102. This independent drive design can reduce mutual interference and influence, and improve the accuracy and stability of bonding.

[0086] In some embodiments, see further Figure 1 and Fig.10 The wavelength conversion layer 30 also includes a third wavelength conversion unit 303. The third wavelength conversion unit 303 is arranged corresponding to all the LED units 201 in another display screen 20 to form a third display module 300. The third wavelength conversion unit 300 can convert the first color light into the fourth color light. The wavelength conversion layer 30 is located on the side of the display screen 20 away from the driving substrate 10. Through the setting of the wavelength conversion layer 30, the first color light emitted by the LED unit 201 can be converted into other color lights, which provides a light source basis for the subsequent combination of multiple different color lights.

[0087] In some embodiments, the “~” symbol in the drawings represents multiple omitted repeating structures, and multiple specifically refers to a number greater than or equal to 2.

[0088] In some embodiments, the display screen 20 further includes a grid layer 202, a passivation layer 203 and an electrode layer 204, wherein the grid layer 202 is located on the surface of the driving substrate 10 facing the wavelength conversion layer 30; the grid layer 202 has a plurality of grid holes 2021 corresponding to the LED units 201, and the LED units 201 are arranged in the corresponding grid holes 2021; the first wavelength conversion unit 301, the second wavelength conversion unit 302, and the third wavelength conversion unit 303 are filled in the grid holes 2021; the passivation layer 203 covers the side of the LED unit 201; the electrode layer 204 covers the side of the passivation layer 203 away from the LED unit 201, and the electrode layer 204 is electrically connected to the top surfaces of the driving substrate 10 and the LED unit 201 respectively; the passivation layer 203 electrically isolates the electrode layer 204 from the LED unit 201.

[0089] It can be understood that the grid layer 202 is located on the side surface of the driving substrate 10 facing the wavelength conversion layer 30, and has a plurality of grid holes 2021 corresponding to the LED units 201, which can effectively block the light interference from other LED units 201, improve the contrast and clarity of the display screen 20, and improve the display effect. The first wavelength conversion unit 301, the second wavelength conversion unit 302 and the third wavelength conversion unit 303 are filled in the grid holes 2021, so that the distance between the wavelength conversion layer 30 and the LED unit 201 is closer, reducing the loss and scattering of light transmission, and improving the efficiency and accuracy of wavelength conversion; the electrode layer 204 is electrically connected to the top surface of the driving substrate 10 and the LED unit 201 respectively, and the passivation layer 203 electrically isolates the electrode layer 204 from the LED unit 201, which can effectively isolate the electrode layer and the LED unit to prevent electrical short circuit and interference. At the same time, the application of the passivation layer 203 can also improve the stability and reliability of the LED unit 201.

[0090] In some embodiments, the material of the grid layer 202 is selected from at least one of organic resin, organic black matrix photoresist, color filter photoresist, and polyimide.

[0091] In some embodiments, the material of the passivation layer 203 is selected from inorganic materials or organic materials to isolate and protect the LED unit 201, and the inorganic materials include any one or a combination of SiO2, Al2O3, ZrO2, TiO2, Si3N4, and HfO2; the organic materials include any one or a combination of black matrix photoresist, color filter photoresist, polyimide, barrier glue (BANK), overcoat glue, near-ultraviolet negative photoresist, and styrene.

[0092] In some embodiments, the material of the electrode layer 204 is at least one of indium tin oxide, Cr, Ti, Pt, Au, Al, Cu, Ge, or Ni.

[0093] In some embodiments, see Figure 1 The display chip also includes a bonding layer 40 and an etching stop layer 50. The bonding layer 40 is arranged between the driving substrate 10 and the LED unit 201, and the LED unit 201 is electrically connected to the bonding layer 40; the passivation layer 203 also covers the side wall of the bonding layer 40 and electrically isolates the electrode layer 204 from the bonding layer 40; the etching stop layer 50 is located on the side surface of the electrode layer 204 facing the wavelength conversion layer 30; the electrode layer 204 also has a light emitting hole 2041 exposing the LED unit 201, and the etching stop layer 50 fills the light emitting hole 2041 and covers the top surface of the LED unit 201.

[0094] In some embodiments, the bonding layer 40 is an adhesive material layer, and can also be electrically connected to the LED unit 201 to play an electrical conduction role. The material of the bonding layer 40 is metal or metal alloy. In some embodiments, the bonding layer 40 may include Au, Ag, Cu, Al and alloys thereof, but is not limited thereto.

[0095] In some embodiments, the material of the etching stop layer 50 is selected from silicon dioxide, silicon nitride, aluminum oxide, etc. The main function of the etching stop layer 50 is to protect the LED unit 201 from being mistakenly etched during the etching process. The etching stop layer 50 also has a shielding function to prevent the etchant from entering the LED unit 201.

[0096] In some embodiments, see further Figure 1 The display screen 20 further includes a reflective layer 205, which covers at least the side wall of the grid hole 2021; the etching stop layer 50 is located between the reflective layer 205 and the electrode layer 204, and electrically isolates the reflective layer 205 and the electrode layer 204. The reflective layer 205 is located on the side wall of the grid hole 2021, and can effectively reflect the light emitted by the LED unit 201. Through the reflection of the reflective layer 205, the light can be guided back to the front of the display screen, thereby improving the light utilization efficiency. The reflective layer 205 can also reduce the scattering and loss of light. By reflecting the light back to the display screen 20, the energy loss can be reduced, and the energy efficiency of the display screen can be improved. In addition, the etching stop layer 50 is located between the reflective layer 205 and the electrode layer 204, and plays a role of electrical isolation, so that electrical short circuit or interference between the electrode layer 204 and the reflective layer 205 can be prevented, thereby improving the stability and reliability of the display screen. The reflective layer 205 is made of reflective material, such as Al, Ag, etc.

[0097] In some embodiments, see further Figure 1 , the reflective layer 205 also covers the surface of the grid layer 202 away from the driving substrate 10, and the surface of the reflective layer 205 away from the grid layer 202 is flush with the surface of the wavelength conversion layer 30 away from the display screen 20. The reflective layer 205 is located between the grid layer 202 and the wavelength conversion layer 30, and can effectively reflect the light emitted from the LED unit 201. By covering the grid layer 202 and being flush with the wavelength conversion layer 30, it is ensured that a flattened surface facing away from the driving substrate 10 is formed, and the reflective layer 205 can capture and reflect light to the maximum extent, thereby improving the light reflection efficiency. In addition, the covering of the reflective layer 205 and the setting of being flush with the wavelength conversion layer 30 will not be blocked or scattered by the grid layer 202 or the wavelength conversion layer 30, thereby maintaining the transmission efficiency and directionality of the light.

[0098] In some embodiments, see Figure 1The display chip further includes a first filter layer 60, a second filter layer 70 and a third filter layer 80; the first filter layer 60 is located on the surface of the first wavelength conversion unit 301 away from the LED unit 201, and the first filter layer 60 is used to filter other color lights and allow the second color light to pass through; the second filter layer 70 is located on the surface of the second wavelength conversion unit 302 away from the LED unit 201, and the second filter layer 70 is used to filter other color lights and allow the third color light to pass through; the third filter layer 80 is located on the surface of the third wavelength conversion unit 303 away from the LED unit 201, and the third filter layer 80 is used to filter other color lights and allow the fourth color light to pass through.

[0099] It should be noted that the first color light emitted by the LED unit 201 is converted into the second color light, the third color light and the fourth color light by three different wavelength conversion units. For example, the first color light and the second color light can both be blue light, the third color light can be red light, and the fourth color light can be green light; or, the first color light can be ultraviolet light, the second color light can be red light, the third color light can be green light, and the fourth color light can be blue light. In this way, full-color display of the display chip can be achieved.

[0100] In some embodiments, the first color light first filter layer 60, the second color filter layer 70 and the third color filter layer 80 are respectively made of filter materials. For example, the first color light can be ultraviolet light, the second color light can be red light, the third color light can be green light, and the fourth color light can be blue light. The first filter layer 60 uses a red filter material to allow red light to pass through; the second filter layer 70 uses a green filter material to allow green light to pass through; the third filter layer 80 uses a blue filter material to allow blue light to pass through. Among them, the filter material can be an organic color filter photoresist, a Bragg distributed reflector, etc.

[0101] In some embodiments, the wavelength conversion layer is made of a color conversion material, and the color conversion material includes wavelength conversion particles, such as fluorescent powder or quantum dots.

[0102] In some embodiments, see further Figure 8, the LED unit 201 is a step structure, which includes a first doped semiconductor layer 2011, a second doped semiconductor layer 2012 and an active layer 2013 located therebetween; the step structure disconnects and electrically isolates the adjacent second doped semiconductor layer 2012, the active layer 2013 and the first doped semiconductor layer 2011; the contact 102 is electrically connected to the corresponding first doped semiconductor layer 2011. It can be understood that the step structure can prevent the currents of adjacent LED units 201 from interfering with each other, thereby improving the independence and stability of the LED units 201.

[0103] In some embodiments, the LED unit 201 may be in a trapezoidal structure. That is, the side wall of the LED unit 201 may be an inclined surface, and the angle between the side wall and the top surface may be an obtuse angle, thereby improving the focusing effect of the LED unit 201. It should be understood that the LED unit 201 may also be in a columnar structure, in which case the angle between the side wall and the top surface of the LED unit 201 is a right angle.

[0104] In some embodiments, the first doped semiconductor layer 2011 and the second doped semiconductor layer 2012 may include one or more layers based on IIVI materials (such as ZnSe or ZnO) or IIIV nitride materials (such as GaN, AlN, InN, InGaN, GaP, AlInGaP, AlGaAs and alloys thereof).

[0105] In some embodiments, the first doped semiconductor layer 2011 may be p-type GaN. In some embodiments, the first doped semiconductor layer 2011 may be p-type InGaN. In some embodiments, the first doped semiconductor layer 2011 may be p-type AlInGaP.

[0106] In some embodiments, the second doped semiconductor layer 2012 may be n-type GaN. In some embodiments, the second doped semiconductor layer 2012 may be n-type InGaN. In some embodiments, the second doped semiconductor layer 2012 may be n-type AlInGaP.

[0107] In some embodiments, the active layer 2013 is an active region of the LED unit 201. The active layer 2013 is disposed between the first doped semiconductor layer 2011 and the second doped semiconductor layer 2012 and provides light. The active layer 2013 is a layer that recombine holes and electrons provided from the first doped semiconductor layer 2011 and the second doped semiconductor layer 2012, respectively, and outputs light of a specific wavelength, and the active layer 2013 may have a single quantum well structure or a multiple quantum well (MQW) structure and a well layer and a barrier layer alternately stacked.

[0108] In some embodiments, the spacing between the LED units 201 is 0.1-10 μm, and the size of the LED unit 201 is 0.1-10 μm. For example, the spacing between the LED units 201 is any one of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm, or a range between any two values; the size of the LED unit 201 is any one of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm, or a range between any two values.

[0109] In some embodiments, the LED unit 201 can emit any one of red light, green light, blue light, yellow light or ultraviolet light.

[0110] In some embodiments, the drive substrate 10 may include semiconductor materials such as silicon, silicon carbide, home nitride, germanium, home arsenide, indium phosphide. The drive substrate 10 may have a drive circuit formed therein, and the drive substrate 10 may be a CMOS backplane or a thin film field effect transistor drive board.

[0111] In some embodiments, see further Figure 1 The driving substrate 10 further includes a common contact 101, and the second doped semiconductor layers 2012 of the plurality of LED units 201 are connected to the corresponding common contact 102; wherein the common contact 101 may be a cathode metal contact, and the contact 102 may be an anode metal contact. The contact 102 is independently connected to each LED unit 201, applies an anode voltage, and provides a separate driving signal, so as to achieve the purpose of individually controlling the light emission of each LED unit 201.

[0112] In some embodiments, a method for preparing a micro light emitting diode display chip is provided, comprising:

[0113] See also Figure 2 and Figure 3 , providing a driving substrate 10, the driving substrate 10 includes a plurality of contacts 101; the driving substrate 10 is a complementary metal oxide semiconductor CMOS device, and the CMOS device can form a driving circuit in the driving substrate 10.

[0114] See also Figure 4, providing a substrate 90, and forming an LED epitaxial layer 901 on the substrate 90; the substrate 90 may be a silicon substrate or a sapphire substrate, and the specific process of forming the LED epitaxial layer 901 on the substrate 90 is: depositing an n-type layer, an activation layer, and a p-type layer on the substrate 90 respectively. These layers can be grown using methods such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy, and precise deposition and film thickness control can be achieved by controlling parameters such as temperature, flow rate, and reaction time.

[0115] See also Figure 5 , forming an LED epitaxial layer 901 on the driving substrate 10, and removing the substrate 90; wherein, first forming a bonding layer 40 on the driving substrate 10 and the LED epitaxial layer 90, and then flipping the substrate 90 so that the bonding layer 40 on the substrate 90 is opposite to the bonding layer 40 on the driving substrate 10, and through the fusion of the bonding layer 40, the LED epitaxial layer 901 can be bonded to the driving substrate 10, and then the substrate 90 is peeled off to achieve the bonding of the driving substrate 10 and the LED epitaxial layer 901 through the bonding layer 40. The peeling method includes but is not limited to laser peeling, dry etching, wet etching, mechanical polishing, etc. The bonding layer 40 can be prepared by atomic layer deposition (ALD), chemical vapor deposition (CVD), evaporation, sputtering, etc. In some embodiments, it is also necessary to perform a thinning operation on the flipped LED epitaxial layer 901, and the thinning operation includes dry etching, wet etching or mechanical polishing.

[0116] See also Figure 6 and Figure 7 , the LED epitaxial layer 901 is separated into a plurality of processing areas 400, and the LED epitaxial layer 901 in each processing area 400 is etched to form a display screen 20, and the plurality of display screens 20 are located in the same plane; the display screen 20 includes a plurality of LED units 201 arranged in an array, and the LED units 201 are used to emit light of a first color; and the LED units 201 are driven individually through corresponding contacts 101.

[0117] See also Figure 8 and Fig. 9 The specific steps of forming the display screen 20 include: etching the LED epitaxial layer 901 to form a plurality of LED units 201, the LED units 201 are arrayed on the bonding layer 40, and the MESA pattern can be designed according to the patterned mask, and the LED epitaxial layer 901 is etched to form a plurality of LED units 201 with a stepped structure;

[0118] A passivation layer 203 is formed on the side of the first LED unit 201 and the side of the bonding layer 40; the passivation layer 203 is formed by deposition, sputtering, etc., and the passivation layer 203 can be used to form a protective structure on the surface of the LED unit 201 to prevent contaminants etched in a subsequent etching process from being sputtered on the surface of the LED unit 201;

[0119] An electrode layer 204 is formed on the side of the passivation layer 203 away from the LED unit 201. The electrode layer 204 is electrically connected to the corresponding contact 101 and the top surface of the LED unit 201. The passivation layer 203 electrically isolates the electrode layer 204 from any of the LED unit 201 and the bonding layer 40. The electrode layer 204 is made of a transparent conductive material.

[0120] See also Figure 8 and Fig. 9 , a light exit hole 2041 is formed at a position of the electrode layer 204 corresponding to the top surface of the LED unit 201, and an etching stop layer 50 is formed on the surface of the electrode layer 204 away from the driving substrate 10; the etching stop layer 50 fills the light exit hole 2041 and covers the electrode layer 204 and the top surface of the LED unit 201; the light exit hole 2041 can be formed by dry etching; the etching stop layer 50 is used to prevent the LED unit 201 from being protected when the grid layer 202 is subsequently formed;

[0121] A grid layer 202 is formed on the surface of the driving substrate 10 facing the display screen 20, and a plurality of grid holes 2021 corresponding to the LED units 201 are formed on the grid layer 202, and the plurality of LED units 201 are arranged in the corresponding grid holes 2021; the grid holes 2021 can be formed by dry etching; the grid holes 2021 are used for emitting light emitted by the LED units 201, and are also used for subsequently filling different wavelength conversion units to realize the conversion of different color lights.

[0122] See also Fig. 9 After the step of forming the grid layer 202, it also includes: forming a reflective layer 205 on the side wall of the grid hole 2021 and the surface of the grid layer 202 away from the driving substrate 10; the etching stop layer 50 is located between the reflective layer 205 and the electrode layer 204, and the etching stop layer 50 electrically isolates the reflective layer 205 and the electrode layer 204.

[0123] See also Figure 1 and Fig.10, a wavelength conversion layer 30 is formed on the side of the display screen 20 away from the driving substrate 10, and the wavelength conversion layer 30 includes a first wavelength conversion unit 301 and a second wavelength conversion unit 302; the first wavelength conversion unit 301 is correspondingly arranged on all the LED units 201 in one display screen 20 to form a first display module 100, and the first wavelength conversion unit 301 can convert the first color light into the second color light; the second wavelength conversion unit 302 is correspondingly arranged on all the LED units 201 in another display screen 20 to form a second display module 200, and the second wavelength conversion unit 302 can convert the first color light into the third color light. The wavelength conversion layer 30 also includes a third wavelength conversion unit 303; the third wavelength conversion unit 303 is correspondingly arranged on all the LED units 201 in another display screen 20 to form a third display module 300, and the third wavelength conversion unit 303 can convert the first color light into the fourth color light.

[0124] It can be understood that the method of the present application realizes the preparation of multiple display screens 20 on the same plane by separating multiple processing areas 400 on the driving substrate 10. The highly integrated LED unit 201 can improve the compactness and space utilization of the chip, and completes the design of the display module by combining with the wavelength conversion layer 30, realizing the chip's multi-color display and improving the color display capability of the display chip.

[0125] In some embodiments, the step of forming the wavelength conversion layer 30 further includes: filling all grid holes 2021 in the grid layer 202 of one display screen 20 with a first wavelength conversion unit 301; filling all grid holes 2021 in the grid layer 202 of another display screen 20 with a second wavelength conversion unit 302; filling all grid holes 2021 in the grid layer 202 of another display screen 20 with a third wavelength conversion unit 303; wherein any display screen 20 emits light of one color.

[0126] See also Figure 1 After the step of forming the wavelength conversion layer 30, the method further includes: forming a first filter layer 60 on a surface of the first wavelength conversion unit 301 away from the LED unit 201, the first filter layer 60 is used to filter other color lights and allow the second color light to pass through; forming a second filter layer 70 on a surface of the second wavelength conversion unit 302 away from the LED unit 201, the second filter layer 70 is used to filter other color lights and allow the third color light to pass through; forming a third filter layer 80 on a surface of the third wavelength conversion unit 303 away from the LED unit 201, the third filter layer 80 is used to filter other color lights and allow the fourth color light to pass through.

[0127] It should be noted that the embodiment of the present application does not specifically limit the sequence of steps in the method for preparing the micro light emitting diode display chip.

[0128] In the embodiments of the manufacturing method in the present application, only the manufacturing process or steps are described. The device structure, shape, material, etc. not described can refer to the above-mentioned embodiments of the micro light emitting diode display chip and will not be repeated here.

[0129] See also Fig.11 and Fig.12 , a display device is provided, comprising the above-mentioned micro light emitting diode display chip and a light combining module 2. The light emitting direction of the display screen 20 is a first direction X, the direction in which at least two of the first display module 100, the second display module 200 and the third display module 300 are arranged in a spaced manner is a second direction Y, and the first direction X intersects with the second direction Y. The display chip and the light combining module 2 are arranged correspondingly in the first direction X.

[0130] See also Fig.11 The light combining module 2 includes a first light combining unit 21 and a second light combining unit 22 located in the same plane and spaced apart along the second direction Y; the first light combining unit 21 is correspondingly arranged with the first display module 100 in the first direction X, and the first light combining unit 21 is used to convert the second color light from the first direction X to emit in the second direction Y; the second light combining unit 22 is correspondingly arranged with the second display module 200 in the first direction X, and the second light combining unit 22 is used to convert the third color light from the first direction X to emit in the second direction Y, and allow the second color light emitted in the second direction Y to pass. The light combining module 2 also includes a third light combining unit 23, which is located in the same plane as the first light combining unit 21 and the second light combining unit 22, and is arranged on a side of the second light combining unit 22 away from the first light combining unit 21 along the second direction Y; the third light combining unit 23 and the third display module 300 are correspondingly arranged in the first direction X, and the third light combining unit 23 is used to convert the fourth color light from the first direction X to be emitted in the second direction Y, and to allow any of the second color light and the third color light emitted in the second direction Y to pass through.

[0131] It can be understood that the display device arranges display modules emitting light of different colors on the same driving substrate 10, so that the light output of the display modules is aligned on the surface along the second direction Y. It is only necessary to adjust the angle and front-to-back distance of the first light combining unit 21, the second light combining unit 22 and the third light combining unit 23 to complete the light combining of multiple colors. Compared with the light combining structure of multiple independent display chips through a prism, the alignment difficulty of the present application is greatly improved, and the structure of the light combining module 2 is simpler and has a wide range of application scenarios.

[0132] by Fig.11For example, the display device is not only used for three-color light combination, the driving substrate 10 is not limited to three colors, and is not limited to three display modules.

[0133] Specifically, the combination of colors on the driving substrate can be: the first display module 100, the second display module 200 and the third display module 300 all emit light of one color, such as red light, green light or blue light, to achieve brightening of monochromatic light; or the first display module 100 emits red light, the second display module 200 emits green light, and the third display module 300 emits blue light to achieve three-color full-color display; or, the number of display modules is greater than three, and three of the display modules emit red, green and blue light, respectively, and one display module emits white light, and the brightness of the three-color combined light is enhanced by white light; or, the number of display modules is greater than three, and two of the display modules emit red light, one display module emits green light, and one display module emits blue light, and an additional display module that emits red light can make up for the problem of weak red light.

[0134] See also Fig.12 The first light-combining unit 21 has a first optical film 211 facing the first display module 100, and the orthographic projection of the first optical film 211 on the driving substrate 10 along the first direction X covers the first display module 100; the second light-combining unit 22 has a second optical film 221 facing the second display module 200, and the orthographic projection of the second optical film 221 on the driving substrate 10 along the first direction X covers the second display module 200; the third light-combining unit 23 has a third optical film 231 facing the third display module 300, and the orthographic projection of the third optical film 231 on the driving substrate 10 along the first direction X covers the third display module 300.

[0135] In some embodiments, any one of the first optical film 211, the second optical film 221, and the third optical film 231 is tilted relative to the surface of the driving substrate 10, and the first optical film 211, the second optical film 221, and the third optical film 231 are arranged parallel to each other. It can be understood that the tilt angle range is 30 to 60 degrees, which can ensure the stability of light combination.

[0136] In some embodiments, the first optical film 211, the second optical film 221, and the third optical film 231 may be polarized beam splitting films, which are composite films of multilayer metal or semiconductor materials, and achieve polarization and spectral separation of light by utilizing the interference effect of the multilayer films.

[0137] In some embodiments, the surfaces of the first light combining unit 21, the second light combining unit 22, and the third light combining unit 23 may also be made of a single-sided highly reflective transparent material, and the second light combining unit 22 and the third light combining unit 23 also need to be made of a material with high transmittance to facilitate the transmission of the first color light and the second color light. Specifically, the high transmittance material may include transparent glass, silicon nitride, etc.

[0138] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0139] The present invention has been introduced in detail above. Specific examples have been applied in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present invention. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A micro light emitting diode display chip, characterized in that: include: A driving substrate (10), wherein the driving substrate (10) comprises a plurality of contacts (102); A plurality of display screens (20), the plurality of display screens (20) being arranged at intervals on the driving substrate (10), and the plurality of display screens (20) being located on the same plane; the display screens (20) comprising a plurality of LED units (201) arranged in an array, the LED units (201) being used to emit light of a first color, and the LED units (201) being driven individually via corresponding contacts (102); A wavelength conversion layer (30), the wavelength conversion layer (30) being arranged on a side of the display screen (20) away from the driving substrate (10); the wavelength conversion layer (30) comprising a first wavelength conversion unit (301) and a second wavelength conversion unit (302); the first wavelength conversion unit (301) being arranged correspondingly with all the LED units (201) in one display screen (20) to form a first display module (100), and the first wavelength conversion unit (301) being capable of converting the first color light into second color light; the second wavelength conversion unit (302) being arranged correspondingly with all the LED units (201) in another display screen (20) to form a second display module (200), and the second wavelength conversion unit (302) being capable of converting the first color light into third color light.

2. The micro light emitting diode display chip according to claim 1, characterized in that: The wavelength conversion layer (30) further comprises a third wavelength conversion unit (303), wherein the third wavelength conversion unit (303) is arranged correspondingly to all the LED units (201) in another display screen (20) to form a third display module (300), and the third wavelength conversion unit (300) is capable of converting the first color light into a fourth color light.

3. The micro light emitting diode display chip according to claim 1, characterized in that: The display screen (20) further comprises: A grid layer (202), the grid layer (202) being located on a surface of a side of the driving substrate (10) facing the wavelength conversion layer (30); the grid layer (202) having a plurality of grid holes (2021) corresponding to the LED units (201), the LED units (201) being arranged in the corresponding grid holes (2021); and the first wavelength conversion unit (301) and the second wavelength conversion unit (302) being filled in the corresponding grid holes (2021).

4. The micro light emitting diode display chip according to claim 3, characterized in that: The display screen (20) further comprises: a bonding layer (40), the bonding layer (40) being provided between the driving substrate (10) and the LED unit (201), and the LED unit (201) being electrically connected to the bonding layer (40); A reflective layer (205), wherein the reflective layer (205) at least covers the side walls of the grid holes (2021).

5. The micro light emitting diode display chip according to claim 4, characterized in that: The display screen also includes: a passivation layer (203), the passivation layer (203) covering a side surface of the LED unit (201); an electrode layer (204), the electrode layer (204) covering a side of the passivation layer (203) away from the LED unit (201), the electrode layer (204) being electrically connected to the driving substrate (10) and the top surface of the LED unit (201) respectively; the passivation layer (203) electrically isolates the electrode layer (204) from the LED unit (201); the passivation layer (203) also covers a side wall of the bonding layer (40) and electrically isolates the electrode layer (204) from the bonding layer (40); An etching stopper layer (50), the etching stopper layer (50) being located on a side surface of the electrode layer (204) facing the wavelength conversion layer (30); the electrode layer (204) also has a light exit hole (2041) exposing the LED unit (201), the etching stopper layer (50) filling the light exit hole (2041) and covering the top surface of the LED unit (201); the etching stopper layer (40) being located between the light reflecting layer (205) and the electrode layer (204), and electrically isolating the light reflecting layer (205) and the electrode layer (204).

6. The micro light emitting diode display chip according to claim 1, characterized in that: Also includes: a first filter layer (60), the first filter layer (60) being located on a surface of the first wavelength conversion unit (301) on a side away from the LED unit (201), the first filter layer (60) being used to filter other color lights and allow the second color light to pass through; A second filter layer (70), the second filter layer (70) is located on a surface of the second wavelength conversion unit (302) on a side away from the LED unit (201), and the second filter layer (70) is used to filter other color lights and allow the third color light to pass through.

7. The micro light emitting diode display chip according to claim 1, characterized in that: The LED unit (201) is a step structure, comprising a first doped semiconductor layer (2011), a second doped semiconductor layer (2012) and an active layer (2013) located therebetween; the step structure disconnects and electrically isolates the adjacent second doped semiconductor layer (2012), the active layer (2013) and the first doped semiconductor layer (2011); and the contact (102) is electrically connected to the corresponding first doped semiconductor layer (2011).

8. The micro light emitting diode display chip according to claim 2, characterized in that: The size of the LED unit (201) is 0.1-10 μm; or The driving substrate (10) is a silicon-based CMOS driving board or a thin film field effect transistor driving board.

9. A method for preparing a micro light emitting diode display chip, characterized in that: include: Providing a driving substrate (10), wherein the driving substrate (10) comprises a plurality of contacts (102); forming an LED epitaxial layer (901) on the driving substrate (10); The LED epitaxial layer (901) is separated into a plurality of processing areas (400), and the LED epitaxial layer (901) of each processing area (400) is etched to form a display screen (20), wherein the plurality of display screens (20) are located on the same plane; the display screen (20) comprises a plurality of LED units (201) arranged in an array, wherein the LED units (201) are used to emit light of a first color; and the LED units (201) are driven individually through the corresponding contacts (102); A wavelength conversion layer (30) is formed on a side of the display screen (20) facing away from the driving substrate (10), and the wavelength conversion layer (30) comprises a first wavelength conversion unit (301) and a second wavelength conversion unit (302); the first wavelength conversion unit (301) is correspondingly arranged on all the LED units (201) in one display screen (20) to form a first display module (100), and the first wavelength conversion unit (301) can convert the first color light into the second color light; and the second wavelength conversion unit (302) is correspondingly arranged on all the LED units (201) in another display screen (20) to form a second display module (200), and the second wavelength conversion unit (302) can convert the first color light into the third color light.

10. The method for preparing a micro light emitting diode display chip according to claim 9, characterized in that: The wavelength conversion layer (30) further comprises a third wavelength conversion unit (303); the third wavelength conversion unit (303) is correspondingly arranged on all the LED units (201) in another display screen (20) to form a third display module (300), and the third wavelength conversion unit (303) is capable of converting the first color light into a fourth color light.

11. The method for preparing a micro light emitting diode display chip according to claim 9, characterized in that: The step of forming the LED epitaxial layer (901) on the driving substrate (10) further comprises: A substrate (90) is provided, wherein the substrate (90) has an LED epitaxial layer (901); a bonding layer (40) is formed on the driving substrate (10) and / or the LED epitaxial layer (90); the driving substrate (10) and the LED epitaxial layer (901) are bonded via the bonding layer (40); and the substrate (90) is removed.

12. The method for preparing a micro light emitting diode display chip according to claim 11, characterized in that: The step of etching the LED epitaxial layer (901) of each processing area (400) to form a display screen (20) comprises: Etching the LED epitaxial layer (901) to form a plurality of LED units (201), wherein the LED units (201) are arranged in an array on the bonding layer (40); A grid layer (202) is formed on a surface of the driving substrate (10) facing the display screen (20), a plurality of grid holes (2021) corresponding to the LED units (201) are formed on the grid layer (202), and a plurality of LED units (201) are arranged in the corresponding grid holes (2021); A reflective layer (205) is formed on the side walls of the grid holes (2021) and on the surface of the grid layer (202) on a side away from the drive substrate (10).

13. The method for preparing a micro light emitting diode display chip according to claim 12, characterized in that: The step of etching the LED epitaxial layer (901) of each processing area (400) to form a display screen (20) further includes: forming a passivation layer (203) on the side surface of the LED unit (201) and the side surface of the bonding layer (40); An electrode layer (204) is formed on a side of the passivation layer (203) away from the LED unit (201), the electrode layer (204) being electrically connected to the driving substrate (10) and the top surface of the LED unit (201) respectively, and the passivation layer (203) electrically isolates the electrode layer (204) from any one of the LED unit (201) and the bonding layer (40); A light exit hole (2041) is formed at a position of the electrode layer (204) corresponding to the top surface of the LED unit (201), and an etching stop layer (50) is formed on the surface of the electrode layer (204) on a side away from the driving substrate (10); the etching stop layer (50) fills the light exit hole (2041) and covers the electrode layer (204) and the top surface of the LED unit (201); the etching stop layer (50) is located between the light reflecting layer (205) and the electrode layer (204), and the etching stop layer (50) electrically isolates the light reflecting layer (205) and the electrode layer (204).

14. The method for preparing a micro light emitting diode display chip according to claim 9, characterized in that: The step of forming the wavelength conversion layer (30) further comprises: Filling first wavelength conversion units (301) in all grid holes (2021) in a grid layer (202) of a display screen (20); and / or A second wavelength conversion unit (302) is filled in all grid holes (2021) in the grid layer (202) of another display screen (20).

15. The method for preparing a micro light emitting diode display chip according to claim 9, characterized in that: After the step of forming the wavelength conversion layer (30), the method further comprises: A first filter layer (60) is formed on a surface of the first wavelength conversion unit (301) at a side away from the LED unit (201), wherein the first filter layer (60) is used to filter other color lights and allow the second color light to pass through; A second filter layer (70) is formed on a surface of the second wavelength conversion unit (302) at a side away from the LED unit (201), and the second filter layer (70) is used to filter other color lights and allow the third color light to pass through.

16. A display device, characterized in that: A micro-light emitting diode display chip comprising any one of claims 1-8; or a micro-light emitting diode display chip prepared by the method of any one of claims 9-15.

17. The display device according to claim 16, characterized in that: The light emitting direction of the display screen (20) is a first direction (X), the direction in which at least two of the first display module (100), the second display module (200) and the third display module (300) are spaced apart is a second direction (Y), and the first direction (X) intersects with the second direction (Y); The display device further includes: A light combining module (2), the light combining module (2) comprising a first light combining unit (21) and a second light combining unit (22) located in the same plane and arranged at intervals along the second direction (Y); the first light combining unit (21) and the first display module (100) are arranged correspondingly in the first direction (X), and the first light combining unit (21) is used to convert second color light from the first direction (X) to emit in the second direction (Y); the second light combining unit (22) and the second display module (200) are arranged correspondingly in the first direction (X), and the second light combining unit (22) is used to convert third color light from the first direction (X) to emit in the second direction (Y), and to transmit the second color light emitted in the second direction (Y).

18. The display device according to claim 17, characterized in that: The light combining module (2) further comprises a third light combining unit (23), wherein the third light combining unit (23) is located on the same plane as the first light combining unit (21) and the second light combining unit (22), and the third light combining unit (23) is arranged on a side of the second light combining unit (22) away from the first light combining unit (21) along the second direction (Y); The third light combining unit (23) and the third display module (300) are arranged correspondingly in the first direction (X), and the third light combining unit (23) is used to convert the fourth color light from the first direction (X) to emit in the second direction (Y), and to allow any one of the second color light and the third color light emitted in the second direction (Y) to pass through.

19. The display device according to claim 18, characterized in that The first light-combining unit (21) comprises a first optical film (211) facing the first display module (100), and the orthographic projection of the first optical film (211) on the driving substrate (10) along the first direction (X) covers the first display module (100); the second light-combining unit (22) comprises a second optical film (221) facing the second display module (200), and the orthographic projection of the second optical film (221) on the driving substrate (10) along the first direction (X) covers the second display module (200); the third light-combining unit (23) comprises a third optical film (231) facing the third display module (300), and the orthographic projection of the third optical film (231) on the driving substrate (10) along the first direction (X) covers the third display module (300).

20. The display device according to claim 19, characterized in that Any one of the first optical film (211), the second optical film (221), and the third optical film (231) is inclined relative to the surface of the driving substrate (10), and the first optical film (211), the second optical film (221), and the third optical film (231) are arranged parallel to each other.

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