Display module, manufacturing method thereof and display device

Abstract

The invention relates to a display module, a manufacturing method thereof and a display device. The display module comprises a substrate; the light-emitting units are arranged on the substrate, and each light-emitting unit comprises an epitaxial structure and an ohmic contact layer arranged on the epitaxial structure; wherein the ohmic contact resistance of the ohmic contact layers of at least part of the light-emitting units is different from the ohmic contact resistance of the ohmic contact layers of the other light-emitting units, and the epitaxial structure is configured to have a wavelength shift of more than 60 nm under different currents, therefore, at least part of the light-emitting units have light-emitting wavelengths different from those of other light-emitting units under the same driving voltage. According to the display module, the light-emitting units with two light-emitting colors can be more easily integrated on the single substrate so as to improve the manufacturing efficiency, double-color display can be achieved without color conversion, and the display module is more stable.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and in particular, to a display module, a manufacturing method thereof, and a display device. Background Art

[0002] Micro LED (Micro Light Emitting Diode) is expected to be widely applied in near-eye display fields such as VR (Virtual Reality) and AR (Augmented Reality). In the display field, a display module usually requires at least two-color Micro LED chips, which generally requires fabricating Micro LED chips with different light-emitting colors on different substrates respectively, or converting the light of some monochromatic Micro LED chips into other colors by means of quantum dot color conversion.

[0003] However, the efficiency and yield of mass transfer are low at a relatively high pixel density, and the stability of quantum dot materials in the quantum dot color conversion technology is not high, resulting in challenges to the production efficiency and stability of the display module.

[0004] Therefore, how to efficiently and stably achieve two-color display is an urgent problem to be solved. Summary of the Invention

[0005] In view of the deficiencies of the above-mentioned related technologies, the purpose of the present application is to provide a display module, a manufacturing method thereof, and a display device, aiming to solve the problems of low production efficiency and poor stability in the production of two-color display products.

[0006] A display module includes:

[0007] A substrate;

[0008] A plurality of light-emitting units disposed on the substrate, where the light-emitting unit includes an epitaxial structure and an ohmic contact layer disposed on the epitaxial structure;

[0009] The ohmic contact resistance of the ohmic contact layer of at least some of the light-emitting units is different from that of the ohmic contact layers of other light-emitting units, and the epitaxial structure is configured to have a wavelength shift of more than 60 nm at different currents, so that the at least some of the light-emitting units have different emission wavelengths from other light-emitting units under the same driving voltage. In the above display module, the epitaxial structure is configured to have a wavelength shift of more than 60 nm at different currents, that is, at different currents, the emission wavelengths of the epitaxial structure are different, and the maximum wavelength difference exceeds 60 nm, which enables the emission colors of the epitaxial structure to be different at different currents, so that the emission effects of different colors can be satisfied by using at least one epitaxial structure. Therefore, the epitaxial structures on the display module can be the same, which enables these epitaxial structures or each light-emitting unit to be fabricated and transferred together, and it is easier to integrate the light-emitting units of two emission colors on a single substrate, greatly improving the fabrication efficiency.

[0010] Optionally, the diffusion depth of the ohmic contact layer of the at least some of the light-emitting units into the epitaxial structure is different from that of other ohmic contact layers.

[0011] By forming different diffusion depths, the specific contact resistivity of the ohmic contact layer can be effectively made different, and the diffusion depth can be controlled by the process conditions during the fabrication of the ohmic contact layer, and the operability is good.

[0012] Optionally, the ohmic contact areas of the respective ohmic contact layers are the same.

[0013] The sizes of the respective ohmic contact layers are unified, which simplifies the processing and reduces the variables affecting the ohmic contact resistance, making the ohmic contact resistance easier to control; and in some implementation processes, the overall structures of the respective light-emitting units can also be kept consistent.

[0014] Based on the same inventive concept, the present application further provides a method for fabricating a display module, including:

[0015] Providing a substrate;

[0016] Disposing a plurality of light-emitting units on the substrate, the light-emitting units including an epitaxial structure and an ohmic contact layer disposed on the epitaxial structure;

[0017] The ohmic contact resistance of the ohmic contact layer of at least some of the light-emitting units is different from that of other ohmic contact layers, and the epitaxial structure is configured to have a wavelength shift of more than 60 nm at different currents, so that the at least some of the light-emitting units have different emission wavelengths from other light-emitting units under the same driving voltage.

[0018] The manufacturing method of the above display module can more easily integrate light-emitting units of two light-emitting colors on a single substrate, greatly improving the manufacturing efficiency, and realizing dual-color display without color conversion, avoiding the stability problems caused by color conversion materials such as quantum dots.

[0019] Optionally, the step of setting a plurality of light-emitting units on the substrate includes:

[0020] Setting a plurality of the epitaxial structures on the substrate;

[0021] When setting the ohmic contact layer of at least part of the light-emitting units, different annealing conditions are adopted from those of the ohmic contact layers of other light-emitting units, so that the ohmic contact layer of at least part of the light-emitting units has a specific contact resistivity different from that of the ohmic contact layers of other light-emitting units.

[0022] The change of the annealing conditions will lead to different performances of the ohmic contact layer. By controlling the annealing conditions to achieve a differentiated specific contact resistivity, the operability is good.

[0023] Optionally, the substrate includes a circuit layer and a bonding layer laid on the circuit layer, and the bonding layer is connected to the circuit layer;

[0024] After setting the insulating material on the epitaxial structure and before removing the insulating material on the surface of the side of the epitaxial structure away from the substrate, it further includes:

[0025] Patterning the insulating material to form a mask pattern;

[0026] Etching the bonding layer through the mask pattern so that the bonding layer is divided into metal electrodes corresponding to each light-emitting unit respectively, and each metal electrode remains connected to the circuit layer; during the process of etching the bonding layer, the bonding layer forms a back-etched deposit in the etched area to form a retaining wall protruding in the direction away from the substrate.

[0027] The back-etched phenomenon is generated during the etching process, which can make the metal of the bonding layer accumulate in the edge area of the etching, thereby forming a retaining wall protruding in the direction away from the main body of the substrate. The retaining wall can block the lateral light of the light-emitting unit to a certain extent, thereby weakening the light crosstalk between the light-emitting units, and the formation of the retaining wall does not require additional steps, with high processing efficiency and low cost.

[0028] Based on the same inventive concept, the present application also provides a display device, including a frame body and the above display module provided on the frame body.

[0029] The above display device can more easily integrate light-emitting units of two light-emitting colors on a single substrate, greatly improving the production efficiency; and it can achieve dual-color display without color conversion, avoiding the stability problems caused by color conversion materials such as quantum dots; in addition, only a unified driving voltage needs to be provided, without increasing additional control costs. Description of the Drawings

[0030] Figure 1 Schematic diagram of the array of light-emitting units provided by an embodiment of the present application;

[0031] Figure 2 Another schematic diagram of the array of light-emitting units provided by an embodiment of the present application;

[0032] Figure 3 Basic structural schematic diagram of the epitaxial structure provided by an embodiment of the present application;

[0033] Figure 4 Schematic flow chart of the manufacturing method of the display module provided by an embodiment of the present application;

[0034] Figure 5 Refined flow schematic of the manufacturing method of the display module provided by an embodiment of the present application Figure 1 ;

[0035] Figure 6 Schematic diagram of the manufacturing process of a display module provided by an embodiment of the present application;

[0036] Figure 7 Refined flow schematic of the manufacturing method of the display module provided by an embodiment of the present application Figure 2 ;

[0037] Figure 8 Schematic diagram of forming a mask pattern with an insulating material provided by an embodiment of the present application;

[0038] Figure 9 Schematic diagram of etching a metal layer through a mask pattern provided by an embodiment of the present application;

[0039] Figure 10 Refined flow schematic of the manufacturing process of the display module provided by another alternative embodiment of the present application Figure 1 ;

[0040] Figure 11 Schematic diagram of an exemplary epitaxial structure provided by another alternative embodiment of the present application;

[0041] Figure 12 Refined flow schematic of the manufacturing process of the display module provided by another alternative embodiment of the present application Figure 2 ;

[0042] Figure 13Schematic of the manufacturing process of the display module provided in another alternative embodiment of the present application Figure 3 ;

[0043] Figure 14 Schematic of the manufacturing process of the display module provided in another alternative embodiment of the present application Figure 4 ;

[0044] Explanation of reference numerals:

[0045] 101 - First light-emitting unit; 102 - Second light-emitting unit; 103 - First epitaxial structure; 104 - Second epitaxial structure; 201 - First-type semiconductor layer; 202 - Active layer; 203 - Second-type semiconductor layer; 2041 - First ohmic contact layer; 2042 - Second ohmic contact layer; 205 - Current spreading layer; 206 - First bonding metal layer; 207 - Etching mask; 208 - Insulating protection layer; 2001 - u-GaN layer; 2002 - N-GaN layer; 2003 - Electron deceleration layer; 2004 - Low-doped gallium nitride layer; 2005 - Stress release layer; 2006 - Hole accumulation layer; 2007 - p-GaN layer; 301 - Substrate; 302 - Contact; 303 - Bonding layer; 304 - Insulating material; 305 - Common electrode; 306 - Barrier wall; 307 - Growth substrate; 308 - Sacrificial layer; 309 - Second bonding metal layer; 310 - First color purification layer; 311 - Second color purification layer; 312 - Light type adjustment structure. Detailed implementation manners

[0046] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0048] In the related art, it is difficult to prepare dual-color display products; based on this, the present application hopes to provide a solution that can solve the above technical problems, and the detailed content will be elaborated in the subsequent embodiments.

[0049] Embodiment:

[0050] This embodiment provides a display module, which includes but is not limited to a substrate 301 and a plurality of light-emitting units arranged on the substrate 301. In this embodiment, at least some of the light-emitting units on the display module can emit light of different colors, thereby realizing a dual-color display. In practical applications, the light-emitting units can be arranged on the substrate 301 in an array, such as Figure 1 In the example, the light-emitting units are arranged in an array, including two different light-emitting units, each having a different light-emitting wavelength. For ease of description, these light-emitting units are referred to as the first light-emitting unit 101 and the second light-emitting unit 102 in this application, wherein the first light-emitting unit 101 has the same light-emitting wavelength, and the second light-emitting unit 102 has the same light-emitting wavelength, but the first light-emitting unit 101 and the second light-emitting unit 102 have different light-emitting wavelengths; illustratively, the first light-emitting unit 101 and the second light-emitting unit 102 are alternately arranged in columns. In other examples, for example Figure 2 In the example, the first light-emitting unit 101 and the second light-emitting unit 102 may be arranged alternately in the row and column directions. In fact, the light-emitting units may also be arranged in other ways to achieve the purpose of display, which is not described in detail in this application. In addition, for ease of understanding, this embodiment takes two light-emitting units with different wavelengths as an example, but in actual applications, there may be more than two types of light-emitting units in the display module, that is, the display module may also have more than two different light-emitting wavelengths. The projection shape of the light-emitting unit is exemplified as a rectangle. In actual applications, it may also be a triangle, a circle or other polygonal shapes. This application does not limit this, and the specific array number and setting spacing may also be set according to actual needs.

[0051] The light-emitting unit includes an epitaxial structure and an ohmic contact layer arranged on the epitaxial structure. It should be noted that the light-emitting unit in this embodiment is a light-emitting device, which includes an epitaxial structure and structures such as electrodes associated therewith, and the epitaxial structure refers to the semiconductor material part thereof. The light-emitting unit can be a Micro LED chip or other light-emitting chip. In this embodiment, the epitaxial structure is configured to have a wavelength shift of more than 60nm under different currents, that is, under different currents, the emission wavelength of the epitaxial structure is different, and the maximum wavelength difference exceeds 60nm, which makes it possible to produce different luminous colors of the epitaxial structure under different currents, so that different colors of luminous effects can be satisfied by using at least one epitaxial structure. Therefore, in this embodiment, the epitaxial structures on the display module can be the same, which allows these epitaxial structures or each light-emitting unit to be manufactured and transferred together, and it is easier to integrate light-emitting units of two luminous colors on a single substrate 301, greatly improving the manufacturing efficiency.

[0052] Exemplarily, the emission wavelength range of the epitaxial structure can simultaneously cover blue light and green light, so as to achieve blue light and green light respectively under different currents; in some examples, the emission wavelength range of the epitaxial structure can simultaneously cover green light and red light, so as to achieve blue light and green light respectively under different currents; moreover, in some examples, the wavelength shift range of the epitaxial structure under different currents is configured to be wider, so as to simultaneously cover blue light, green light and red light.

[0053] See Figure 3 , the epitaxial structure may include, but is not limited to, a first-type semiconductor layer 201, an active layer 202, and a second-type semiconductor layer 203 stacked in sequence. Among them, the first-type semiconductor layer 201 may be an N-type doped semiconductor layer or a p-type doped semiconductor layer, and the second-type semiconductor layer 203 is the other type opposite to the first-type semiconductor layer 201.

[0054] In practical applications, the light-emitting unit can be formed into a front-mounted or flip-chip structure, or can be formed into a vertical structure. The structures of the light-emitting units can be the same or different. For example, the epitaxial structures of the light-emitting units are not only the same in composition, but also the same in structural form and other aspects.

[0055] In this embodiment, the ohmic contact resistance of the ohmic contact layer of at least some of the light-emitting units is different from that of the ohmic contact layer of other light-emitting units. The different ohmic contact resistances cause different currents to be formed in the light-emitting units under the same driving voltage. When performing display control, only a unified driving voltage needs to be provided, so that the currents applied to a part of the light-emitting units in the display module are different from those of other light-emitting units. Due to the wavelength shift of the epitaxial structure under different currents, a part of the light-emitting units have different emission wavelengths from those of other light-emitting units. It can be seen that in some implementation processes, the display module of this embodiment does not need to perform additional design on the display control means, has high stability and applicability during the control process, and does not increase the control cost; moreover, the display module of this embodiment can achieve dual-color display without color conversion, avoiding the stability problems caused by color conversion materials such as quantum dots.

[0056] In this embodiment, the ohmic contact layer of at least some of the light-emitting units has a specific contact resistivity different from that of other ohmic contact layers. It should be noted that the other ohmic contact layers referred to in this application are the ohmic contact layers on other light-emitting units. It can be understood that the specific contact resistivity of the ohmic contact layer in this embodiment is the specific contact resistivity between it and the epitaxial structure. The specific contact resistivity affects the ohmic contact resistance of the ohmic contact layer, and different ohmic contact resistances cause the light-emitting units to form different currents under the same driving voltage. In some embodiments, the ohmic contact layer of at least some of the light-emitting units has an ohmic contact area different from that of other ohmic contact layers. The ohmic contact area can also affect the ohmic contact resistance of the ohmic contact layer, thereby causing some light-emitting units to form different currents under the same driving voltage.

[0057] The ohmic contact layer may include transparent conductive materials such as indium tin oxide (ITO for short) that can form an ohmic contact with the corresponding semiconductor material. For example: graphene, indium zinc oxide (IZO for short), thin metal film layers, etc. In practical applications, the ohmic contact layers of each light-emitting unit can be made of the same material. For example, indium tin oxide with good ohmic contact effect can be used; in some embodiments, the ohmic contact layers of at least some of the light-emitting units can also be made of different materials from the ohmic contact layers of other light-emitting units, so as to directly form different specific contact resistivities through the differences in the properties of the materials themselves.

[0058] For the case where the ohmic contact layers of the light-emitting units all use the same material, different specific contact resistivities can be achieved by forming differences in other properties of the ohmic contact layer except for the material.

[0059] In some embodiments, the diffusion depth of the ohmic contact layer of at least some of the light-emitting units into the epitaxial structure is different from that of other ohmic contact layers. It can be understood that the relationship between the ohmic contact layer and the epitaxial structure is not a simple direct contact relationship. In fact, during the formation of the ohmic contact layer, the material of the ohmic contact layer will diffuse into the external structure to a certain extent. Different diffusion depths result in differences in the electrical properties between the ohmic contact layer and the epitaxial structure, thereby achieving different specific contact resistivities. Exemplarily, for the diffusion depth of the ohmic contact layer, it can be controlled by changing its processing conditions during the production of the ohmic contact layer, such as using different annealing processes, etc.

[0060] This embodiment does not limit the specific contact resistivity of the ohmic contact layer. Exemplarily, in some Micro LED chips, the specific contact resistivity of the ohmic contact layer is usually controlled to not exceed 10 -2 Ω·cm 2。In order to form a more obvious current difference to ensure the difference in emission colors, in some embodiments, the specific contact resistivity of at least part of the ohmic contact layer is not higher than one-fifth of the specific contact resistivity of other ohmic contact layers. As an example, the specific contact resistivity A of at least part of the ohmic contact layer and the specific contact resistivity B of other ohmic contact layers do not exceed 10 -2 Ω·cm 2 and B≥5A.

[0061] In some embodiments, the ohmic contact areas of the respective ohmic contact layers are the same. It can be understood that the ohmic contact area of the ohmic contact layer is the area in direct contact with the epitaxial structure. This enables the sizes of the ohmic contact layers of the respective light-emitting units to be unified, simplifies processing while reducing the variables affecting the ohmic contact resistance, making it easier to control the ohmic contact resistance of the ohmic contact layer; and in some implementation processes, the overall structures of the respective light-emitting units can also be kept consistent. In practical applications, the ohmic contact areas of the ohmic contact layers of the respective light-emitting units can also be configured to be different. Under the combined action of differences in specific contact resistivity and ohmic contact area, etc., a current difference is formed between at least some light-emitting units and other light-emitting units under the same driving voltage.

[0062] In some embodiments, the light-emitting unit further includes at least one of the following structures:

[0063] A color purification layer, provided in the light-emitting direction of the light-emitting unit, configured to selectively block light, and the wavelength range that can pass through it is related to the emission wavelength of the corresponding light-emitting unit; the color purification layer can be a DBR (distributed Bragg reflector), a filter film, etc. Its function is to achieve band-pass filtering of the light wavelength. By setting it in the light-emitting direction of the light-emitting unit, the irrelevant stray light emitted can be reduced, thereby improving the color purity of the emitted light.

[0064] A light pattern adjustment structure 312, provided in the light-emitting direction of the light-emitting unit, configured to adjust the light-emitting pattern of the light-emitting unit; it includes, but is not limited to, multiple microstructures prepared by means such as nanoimprinting, microlens array transfer, or hot melt photoresist etching of oxides.

[0065] A metal electrode, connecting the epitaxial structure and the substrate 301, and further protruding away from the substrate 301 around the epitaxial structure to form a light-blocking wall 306 that blocks the lateral light of the light-emitting unit; it can be understood that the metal electrode is non-transparent, and it reflects or absorbs the light emitted by the light-emitting unit. Making the side surface of the metal electrode into the structure of the light-blocking wall 306 can achieve the effect of crosstalk suppression.

[0066] The current spreading layer 205 is disposed on the epitaxial structure and on the opposite side of the ohmic contact layer. Exemplarily, the current can be a metal or a transparent conductive material, such as indium tin oxide. Disposing the ohmic contact layer and the current spreading layer 205 on the epitaxial structure can make the current distribution in the epitaxial structure relatively uniform and improve the light-emitting efficiency.

[0067] This embodiment also provides a method for manufacturing a display module. Refer to Figure 4 , the method for manufacturing a display module includes but is not limited to the steps of:

[0068] S101. Provide a substrate;

[0069] S102. Dispose a plurality of light-emitting units on the substrate. The light-emitting units include an epitaxial structure and an ohmic contact layer disposed on the epitaxial structure. The ohmic contact resistance of the ohmic contact layer of at least some of the light-emitting units is different from that of other ohmic contact layers, and the epitaxial structure is configured to have a wavelength shift of more than 60 nm under different currents, so that at least some of the light-emitting units have a different light-emitting wavelength from other light-emitting units under the same driving voltage;

[0070] It can be understood that the display module manufactured by the method for manufacturing a display module of this embodiment may include the display module of the foregoing example. In order to achieve displays of different colors, during the process of manufacturing the light-emitting units, it is necessary to configure the ohmic contact layer of at least some of the light-emitting units to have a different ohmic contact resistance from that of other light-emitting units. Exemplarily, the ohmic contact layer of at least some of the light-emitting units and other ohmic contact layers can adopt different materials, configure different ohmic contact areas, or can be manufactured under different processing conditions to have different ohmic contact resistances.

[0071] In some embodiments, as Figure 5 shown, the step of disposing a plurality of light-emitting units on the substrate 301 includes:

[0072] S201. Dispose a plurality of epitaxial structures on the substrate;

[0073] In this step S201, the epitaxial structure can be manufactured on the substrate 301. For example, a whole epitaxial layer is grown on the growth substrate 307. Since the light-emitting units in the display module of this embodiment can adopt a unified epitaxial structure, the epitaxial layer can be transferred to the substrate 301 as a whole, and a plurality of epitaxial structures can be manufactured from the epitaxial layer by means such as etching. The structural forms of the respective epitaxial structures can be made the same, simplifying the manufacturing process. The manner of forming the epitaxial layer into the required epitaxial structural form can refer to existing manners and will not be elaborated here.

[0074] Each epitaxial structure can also be fabricated and then transferred onto the substrate 301. Exemplarily, a plurality of epitaxial structures are fabricated on a single growth substrate 307, and then each epitaxial structure is transferred onto the substrate 301 by means of mass transfer or the like.

[0075] S202. An ohmic contact layer is provided on the epitaxial structure. The ohmic contact layer is made of the same material. Among them, at least some of the ohmic contact layers of the light-emitting units are set under annealing conditions different from those of the ohmic contact layers of other light-emitting units when being provided.

[0076] It can be understood that in order to perform different annealing treatments, the ohmic contact layer can be provided in at least two times, and each time, it is provided for a part of the light-emitting units. After the ohmic contact layer is provided, an annealing treatment is performed on the ohmic contact layer, and the annealing treatment can change the performance of the ohmic contact layer.

[0077] For ease of understanding, it is assumed that two ohmic contact layers with different ohmic contact resistances are fabricated in two times. In the present application, the two ohmic contact layers formed in these two times are respectively referred to as a first ohmic contact layer 2041 and a second ohmic contact layer 2042. Similarly for easy distinction, the light-emitting unit provided with the first ohmic contact layer 2041 is the first light-emitting unit 101, and the light-emitting unit provided with the second ohmic contact layer 2042 is the second light-emitting unit 102. Their corresponding epitaxial structures are respectively referred to as a first epitaxial structure 103 and a second epitaxial structure 104. In this embodiment, the first ohmic contact layer 2041 and the second ohmic contact layer 2042 are fabricated separately, but it should be understood that the order of the first ohmic contact layer 2041 and the second ohmic contact layer 2042 is not limited, as long as different annealing conditions are adopted.

[0078] Exemplarily, the annealing conditions include but are not limited to the temperature, the temperature change rate, the holding time at each temperature, the composition of the gas introduced, etc. during the annealing treatment process. In this embodiment, at least one annealing condition changes, and this change in the annealing condition will result in different performances of the ohmic contact layer, that is, different ohmic contact resistances. In some implementation processes, the change of certain annealing conditions can cause the diffusion depths of some ohmic contact layers and other ohmic contact layers into the corresponding epitaxial structures to form differences, and further can lead to different specific contact resistivities. However, this embodiment is not limited thereto. Implementing methods in which other performances other than the diffusion depth are made to form differences by controlling the annealing conditions, and further resulting in different specific contact resistivities between the ohmic contact layers are also feasible. In some implementation processes, the influence brought by the annealing conditions can be multi-faceted. On the basis of making the specific contact resistivity of some ohmic contact layers different from that of other ohmic contact layers, the specific annealing conditions can be set according to requirements, and this embodiment does not limit.

[0079] Exemplarily, the differences caused by different annealing conditions; it is assumed that the ohmic contact effect between the first ohmic contact layer 2041 and the first epitaxial structure 103 is better than that between the second ohmic contact layer 2042 and the second epitaxial structure 104. Further, under the same driving voltage, the current of the first light-emitting unit 101 is greater than that of the second light-emitting unit 102, causing the first light-emitting unit 101 and the second light-emitting unit 102 to emit light of different colors.

[0080] In the process of manufacturing the light-emitting unit, there is usually a process of setting the insulating material 304. In some implementation processes, the insulating material 304 covers the epitaxial structure. The set insulating material 304 may be used to form a mask or remain as the insulating protective layer 208 of the light-emitting unit in some areas of the light-emitting unit. Exemplarily, the insulating material 304 includes but is not limited to aluminum oxide, silicon dioxide, etc. In this embodiment, after the relevant manufacturing processes are completed, the insulating material 304 can be removed. To ensure the ohmic contact effect, the insulating material 304 on the surface of the epitaxial structure away from the substrate 301 can be completely removed to ensure that enough area is exposed for subsequent ohmic contact.

[0081] As an example, refer to Figure 6 In S301 shown in, the light-emitting unit can be designed as a vertical structure, that is, electrically connected on opposite sides. The substrate 301 can be provided with contacts 302 for respectively connecting to the epitaxial structure, and the epitaxial structure is bonded to the substrate 301 through a bonding layer 303. The bonding layer 303 can be formed by combining the bonding metal provided on the epitaxial structure and the bonding metal provided on the substrate 301. The bonding metal can be an alloy formed by one or more of conductive metal materials such as Ti / Al / Ti / Au / Cr / pt / In / Sn / Ag, etc. In this example, a display module with two light-emitting wavelengths is manufactured, that is, with two light-emitting units. The first epitaxial structure 103 and the second epitaxial structure 104 respectively represent the epitaxial structures of the light-emitting units with different light-emitting wavelengths.

[0082] Refer to Figure 6In S302, in order to form the insulating protective layer 208, an insulating material 304 is disposed on the epitaxial structure. The insulating material 304 can completely cover the epitaxial structure and the side surfaces of the bonding layer 303. The insulating material 304 can be set to be relatively thick. For example, its thickness can exceed the thickness of the epitaxial structure. In some examples, the insulating material 304 can also be set to be relatively thin, and this example is not limited. Exemplarily, the insulating material 304 includes but is not limited to aluminum oxide, silicon dioxide, etc., and can be set by processes including but not limited to ALD (Atomic Layer Deposition), pECVD (plasma enhanced chemical vapor deposition), etc.

[0083] See Figure 6 In S303, the insulating material 304 on the surface of the epitaxial structure away from the substrate 301 is removed, and the surface of the epitaxial structure away from the substrate 301 is completely exposed. The removal process can be a single process; it can also be divided into two processes, that is, at least part of the insulating material 304 on the epitaxial structure is removed each time. In this example, the surrounding insulating material 304 that is not removed can remain on the surface of the epitaxial structure as the insulating protective layer 208, and the side surfaces of the bonding layer 303 can also be covered and protected.

[0084] See Figure 6 In S304, an ohmic contact layer is disposed on the surface of the epitaxial structure under different conditions. Exemplarily, in this example, the first ohmic contact layer 2041 and the second ohmic contact layer 2042 are respectively fabricated under two different conditions. Figure 6 S304 in the figure schematically shows the structure after fabrication. The insulating material 304 can be set to be relatively thick. After the insulating material 304 is removed, grooves are formed on the first epitaxial structure 103 and the second epitaxial structure 104. In this example, the first ohmic contact layer 2041 and the second ohmic contact layer 2042 can be disposed in the grooves, so that the insulating material 304 can also form insulating protection on the side surfaces of the first ohmic contact layer 2041 and the second ohmic contact layer 2042.

[0085] In practical applications, step S303 can also be correspondingly executed in two times. For example, first, only the insulating material 304 on the first epitaxial structure 103 is removed. After the fabrication of the first ohmic contact layer 2041 is completed, then the insulating material 304 on the second epitaxial structure 104 is removed and the second ohmic contact layer 2042 is fabricated.

[0086] See Figure 6For S305, a common electrode 305 is provided on one side of the first ohmic contact layer 2041 and the second ohmic contact layer 2042. The lines connected to the contacts 302 on the substrate 301 can be controlled separately, so as to control the operation of each light-emitting unit separately. The common electrode 305 can be shared by a plurality of first light-emitting units 101 and second light-emitting units 102, and can be connected to the lines on the substrate 301 through the contacts 302.

[0087] In some embodiments, the insulating material 304 is used as a mask. Refer to Figure 7 As shown, after the insulating material 304 is provided on the epitaxial structure and before the insulating material 304 on the side of the epitaxial structure away from the substrate 301 is removed, the manufacturing method of the display module further includes the steps:

[0088] S401: Pattern the insulating material to form a mask pattern;

[0089] Refer to Figure 8 , in this embodiment, the substrate 301 includes a circuit layer and a bonding layer 303 laid on the circuit layer. The bonding layer 303 is connected to the contact 302 of the circuit layer. Among them, the bonding layer 303 can be a whole layer of metal or a pattern of overall interconnection. At this time, independent light-emitting units have not been formed yet.

[0090] S402: Etch the bonding layer through the mask pattern so that the bonding layer is divided into metal electrodes corresponding to each light-emitting unit respectively, and each metal electrode remains connected to the circuit layer; during the process of etching the bonding layer, the bonding layer is re-deposited in the etched area to form a retaining wall protruding in the direction away from the substrate body;

[0091] In the above embodiment, after the insulating material 304 is provided, all the exposed surfaces on this side of the substrate 301 body are covered by the insulating material 304. Refer to Figure 9, the set insulating material 304 serves as a mask for etching the bonding layer 303 after being patterned. The insulating material 304 after being patterned to form a mask pattern covers the surfaces of the first epitaxial structure 103 and the second epitaxial structure 104, but is removed in the regions corresponding to between each light-emitting unit. The bonding layer 303 is etched through the mask pattern, so that the bonding layer 303 between the light-emitting units is etched, thereby disconnecting the interconnection of the bonding layer 303 between the light-emitting units and forming metal electrodes corresponding to each light-emitting unit respectively. Each metal electrode remains connected to the circuit layer, that is, the metal electrode is still connected to the contact 302. In this embodiment, the process parameters of the etching are controlled to cause a redeposition phenomenon during the etching process, which can make the metal of the bonding layer 303 accumulate in the edge region of the etching, thereby forming a retaining wall 306 protruding in a direction away from the main body of the substrate 301. The retaining wall 306 can block the lateral light of the light-emitting units to a certain extent, thereby weakening the light crosstalk between the light-emitting units. In some examples, the height of the retaining wall 306 can be controlled to be higher than or equal to the thickness of the epitaxial structure to achieve a better crosstalk suppression effect.

[0092] After the etching of the bonding layer 303 is completed, the insulating material 304 on the first epitaxial structure 103 and the second epitaxial structure 104 can be removed as required to expose sufficient areas of the first epitaxial structure 103 and the second epitaxial structure 104 for the fabrication of the ohmic contact layer.

[0093] In addition, this embodiment also provides a display device, which includes a frame body and a display module disposed on the frame body. The display module adopted by the display device includes the display module in the above example. Since the epitaxial structure of the light-emitting unit is configured to have a wavelength shift of more than 60 nm under different currents, by making the ohmic contact resistance of the ohmic contact layer of at least some light-emitting units different from that of the ohmic contact layer of other light-emitting units, the light-emitting units in the display module have different emission wavelengths under the same driving voltage, so that the display device more simply realizes dual-color display and only needs to provide a unified driving voltage without increasing additional control costs.

[0094] Another alternative embodiment

[0095] To better understand the present application, this embodiment further describes the display module and its manufacturing method of the present application in combination with a specific display module manufacturing process. For ease of understanding, in this embodiment, the light-emitting units with different emission wavelengths and their epitaxial structures and ohmic contact layers are distinguished in terms of expression.

[0096] Such as Figure 10In S501, a sacrificial layer 308 is prepared on the growth substrate 307. In this example, the prepared display module is a blue-green dual-color display module, and the main epitaxial material includes gallium nitride. The growth substrate 307 can be a sapphire substrate. In other examples, the growth substrate 307 can be other materials capable of growing semiconductor materials, which can be selected according to the epitaxial materials to be grown. The sacrificial layer 308 is made with holes, and then the epitaxial material is grown on the growth substrate 307. The epitaxial material grows in the holes formed by the sacrificial layer 308. Exemplarily, the sacrificial layer 308 can be oxide materials such as silicon dioxide and silicon nitride, or high-temperature-resistant polymers or compounds such as aluminum arsenide, etc. This example is not limited. The holes of the sacrificial layer 308 have an upper bottom (the side away from the growth substrate 307) and a lower bottom (the side close to the growth substrate 307). The size of the upper bottom is equivalent to that of the contact 302 on the subsequent substrate 301, and the size of the lower bottom is slightly smaller than that of the upper bottom. The depth of the hole is the same as the height to which the epitaxial layer is to be grown. The epitaxial layer grown in this example at least includes a first-type semiconductor layer 201, an active layer 202, and a second-type semiconductor layer 203. It can be selected that the side close to the growth substrate 307 is N-type doped. For the convenience of explaining this embodiment, only the case where the side close to the growth substrate 307 is N-type doped is taken as an example. In fact, when the side close to the growth substrate 307 is a p-doped semiconductor, the steps are the same, and only the positive and negative polarities of the circuit on the substrate 301 need to be changed.

[0097] In this example, the epitaxial layer is grown in the holes, and an epitaxial structure is formed in each hole. For the convenience of explanation, this example takes two holes as an example. The epitaxial structure in one hole is the first epitaxial structure 103, and the epitaxial structure formed in the other hole is the second epitaxial structure 104. In fact, a large number of holes can be formed on the same growth substrate 307, and a plurality of first epitaxial structures 103 and a plurality of second epitaxial structures 104 can be obtained. It can be understood that since the first epitaxial structure 103 and the second epitaxial structure 104 can be formed together on the same growth substrate 307, their components are the same, and the structures can also be the same. In this example, the epitaxial structure is obtained through the holes formed by the sacrificial layer 308, without etching the epitaxial material, avoiding the damage caused by etching, and can improve the radiation efficiency in some implementation processes.

[0098] See Figure 11 , which is a specific example of an epitaxial structure. The epitaxial structure in this example sequentially includes a u-GaN layer 2001, an N-GaN layer 2002, an electron deceleration layer 2003, a low-doped gallium nitride layer 2004, a stress release layer 2005, an active layer 202, a hole accumulation layer 2006, and a p-GaN layer 2007 from the growth substrate 307. Exemplarily, the thickness of the u-GaN layer 2001 is 2.5 μm, and the thickness of the N-GaN layer 2002 is 1.3 μm. Silicon doping can be used, and the doping concentration is 1×101 9 cm-3 ; The thickness of the electron deceleration layer 2003 is 90 nm, which is composed of 15 pairs of superlattices formed by n-GaN / n-AlGaN; the stress release layer 2005 is composed of 6 pairs of superlattice structures formed by In 0.05 Ga 0.95 N with a thickness of 3 nm / GaN with a thickness of 5 nm; the active layer 202 is composed of 15 pairs of quantum well layers formed by In 0.12 Ga 0.88 N with a thickness of 2.5 nm / GaN with a thickness of 7 nm; the hole accumulation layer 2006 is composed of p-doped GaN with a doping concentration greater than 101 9 cm -3 , and its thickness is 60 nm - 80 nm; the p-GaN layer 2007 is composed of Mg-doped GaN with a thickness of 120 nm.

[0099] Continuing Figure 11 from the example, the total thickness of the entire epitaxial wafer can be obtained at 3.8 μm ± 0.5 μm. The thickness of the epitaxial structure of this example is very thin, and combined with a special electron deceleration layer, a low-doped gallium nitride layer, and a stress release layer, there is a strong quantum-confined Stark effect in the epitaxial wafer, thereby realizing green light at low current and blue light at high current, enabling two colors, blue and green, to be achieved on the same epitaxial wafer.

[0100] For example Figure 10 S502 in

[0101] For example Figure 10In S503, a second bonding metal layer 309 is prepared on the substrate 301. The second bonding metal layer 309 can be an alloy formed by one or more of metal materials such as Ti / Al / Au / Cr / pt / In / Sn / Ag / Cu, etc. Subsequently, the substrate 301 and the epitaxial wafer obtained in step S502 are bonded and integrated through the bonding metal layer, and the first bonding metal layer 206 and the second bonding metal layer 309 are combined to form a bonding layer 303. The bonding effect can be achieved by pressurization and heating. The substrate 301 in this example can be a CMOS (Complementary Metal Oxide Semiconductor) driving backplane, and the TFT (Thin Film Transistor) driving backplane can also be LTPS (Low Temperature poly-Silicon). There should be multiple contacts 302 on it, and the center pitch of the contacts 302 should be consistent with the pixel size of the display module to be made. For the convenience of description, only the CMOS backplane is taken as an example in this application, and only some of the contacts 302 are schematically shown. As Figure 10 Taking S503 as an example, for the convenience of description, the leftmost contact 302 in the figure is the N pole, and the remaining contacts 302 in the figure are the p poles. The actual number of specific contacts 302 and the positive and negative electrical properties are not limited.

[0102] See Figure 10 In S504, the growth substrate 307 is removed. The growth substrate 307 in this example is a sapphire substrate, which can be removed by laser lift-off. The laser for laser lift-off can use a solid laser. After the laser lift-off is completed, the removal of gallium metal needs to be synchronized. It should be noted that in some implementation processes, in order to match the epitaxial characteristics, after the growth substrate 307 is removed, the native sputter AlN (aluminum nitride thin film buffer layer) and buffer layers such as the unintentionally doped gallium nitride layer of the gallium nitride material are also etched away to expose the N-type doped gallium nitride, and then the subsequent chip manufacturing process is carried out. For the convenience of description, some steps are omitted in the figure of this example. The structural schematic diagram after the laser lift-off and the removal of the buffer layer is as shown in Figure 10 S504 shown.

[0103] See Figure 10 In S505, the sacrificial layer 308 is removed. The preparation method of the sacrificial layer 308 can be selected according to the material of the sacrificial layer 308 used. Exemplarily, wet etching can be used for removal. The first epitaxial structure 103 and the second epitaxial structure 104 after the removal of the sacrificial layer 308 are used for the fabrication of light-emitting units in the subsequent manufacturing process.

[0104] Continuing with the above example, see Figure 12For S506, a first insulating material 304 is disposed on the first epitaxial structure 103 and the second epitaxial structure 104 to form an etching mask 207, and the etching mask 207 can be selected according to the thickness of the bonding layer 303. The first insulating material 304 includes, but is not limited to, insulating materials such as silicon dioxide and aluminum oxide. After the etching mask 207 is prepared, a patterning etching process is performed to expose the bonding layer 303 that needs to be etched. The structure after the etching mask 207 is prepared is as shown in Figure 12 of S506.

[0105] See Figure 12 For S507, after the preparation of the etching mask 207 is completed, the bonding layer 303 is etched. The purpose of etching the bonding layer 303 is to disconnect between adjacent light-emitting units, thereby obtaining a plurality of independent light-emitting units. Among them, the etching method includes, but is not limited to, ICP (Inductively Coupled plasma) etching or IBE (Ion Beam Etching) etching. In this example, after etching, the metal in the bonding layer 303 will redeposit on the sidewalls, which can be achieved by setting reasonable power and etching process. The redeposited metal forms a barrier wall 306 around, and the height of the barrier wall 306 can be slightly greater than or equal to the epitaxial structure, thereby using the barrier wall 306 to suppress the optical crosstalk between adjacent light-emitting units.

[0106] See Figure 12 For S508, after the metal etching is completed, an insulating protection layer 208 is fabricated. The insulating protection layer 208 includes, but is not limited to, aluminum oxide, silicon dioxide, etc., and it can be the same as or different from the material of the etching mask 207. The insulating protection layer 208 can be disposed by processes including, but not limited to, ALD, pECVD, etc. The insulating protection layer 208 can passivate and insulate the bonding layer 303 and its barrier wall 306 part. The thickness of the insulating protection layer 208 fabricated in this step S508 can be more than twice the depth of the isolation trench between the light-emitting units, thereby ensuring that the material of the insulating protection layer 208 fills the entire isolation trench.

[0107] Continuing with the above example, see Figure 13In step S509, the etch mask 207 is etched to remove the etch mask 207 and the insulating protective layer 208 on the side of the first epitaxial structure 103 and the second epitaxial structure 104 away from the substrate 301. The etching of the etch mask 207 and the insulating protective layer 208 can use a photolithography process. A photoresist is set on the side away from the substrate 301, and the photoresist directly above the first epitaxial structure 103 and the second epitaxial structure 104 is removed through processes such as exposure and development. After the etch mask 207 and the insulating protective layer 208 are removed, a groove is formed in the corresponding area, and the bottom of the groove exposes the first epitaxial structure 103 or the second epitaxial structure 104. The size of the groove can be slightly larger than the area of the first epitaxial structure 103 or the second epitaxial structure 104 on this side to ensure that the surface of this side of the first epitaxial structure 103 or the second epitaxial structure 104 is completely exposed, providing sufficient area for ohmic contact. In some examples, the entire insulating protective layer 208 can also be etched first to expose the etch mask 207 prepared in step S506, and then in step S509, only the exposed etch mask 207 is etched and removed; the specific etching method for the entire-layer etching of the insulating protective layer 208 is not limited, and it can be wet etching or dry etching.

[0108] See Figure 13 In step S510, the first ohmic contact layer 2041 is fabricated. The specific preparation method can be electron beam evaporation or magnetron sputtering, etc. The thickness of the first ohmic contact layer 2041 can be to fill the groove formed by the etch mask 207 and the insulating protective layer 208 in step S509. The preparation method of the first ohmic contact layer 2041 is not limited. It can be prepared as a whole layer and then the ohmic contact layer material in the area other than the first epitaxial structure 103 is removed by etching, or a glue material can be made first and then the lift-off method is used to leave the ohmic contact layer material on the first epitaxial structure 103. After the preparation of the first ohmic contact layer 2041 is completed, rapid annealing is carried out, and the annealing temperature needs to be less than the melting point of the bonding layer 303. In this example, the first ohmic contact layer 2041 achieves a specific contact resistivity ≤ 10 -2 Ω·cm 2 . In this example, the material of the first ohmic contact layer 2041 can be indium tin oxide, but it is not limited thereto. For example, other materials with transparent conductivity and capable of forming an ohmic contact difference with gallium nitride can also be used, such as graphene, indium zinc oxide, thin metal film layers, etc.

[0109] See Figure 13For S511, a second ohmic contact layer 2042 is fabricated. The specific preparation method can be electron beam evaporation, magnetron sputtering, or the like. The thickness of the second ohmic contact layer 2042 can be such that it fills the groove formed by the etching mask 207 and the insulating protection layer 208 in step S509. The preparation method of the second ohmic contact layer 2042 is not limited. The ohmic contact layer material in the area outside the second epitaxial structure 104 can be removed by etching after the whole layer is prepared, or the photoresist can be fabricated first and then the lift-off method can be used to leave the ohmic contact layer material on the second epitaxial structure 104. Of course, the first ohmic contact layer 2041 that has been fabricated is not affected during this process. After the preparation of the second ohmic contact layer 2042 is completed, rapid annealing is performed under annealing conditions different from those during the annealing of the first ohmic contact layer 2041, and the annealing temperature needs to be lower than the melting point of the bonding layer 303. In this example, the specific contact resistivity of the second ohmic contact layer 2042 is ≤ 10 -2 Ω·cm 2 Moreover, the specific contact resistivity B of the second ohmic contact layer 2042 is not less than five times the specific contact resistivity A of the first ohmic contact layer 2041. In this example, the material of the second ohmic contact layer 2042 can also be indium tin oxide, but it is not limited thereto. For example, other materials with transparent conductivity and capable of forming an ohmic contact difference with gallium nitride, such as graphene, indium zinc oxide, and thin metal film layers, can also be used.

[0110] For the first ohmic contact layer 2041 and the second ohmic contact layer 2042 fabricated through the above steps, the ohmic contact effect between the first ohmic contact layer 2041 and the first epitaxial structure 103 is better than that between the second ohmic contact layer 2042 and the second epitaxial structure 104. Thus, under the same driving voltage, the working current on the first epitaxial structure 103 is greater than the working current on the second epitaxial structure 104. In this example, based on the fact that the epitaxial structure is configured to have a wavelength shift of more than 60 nm at different currents, the first current of the first epitaxial structure 103 is larger, making its emission blue light; the second current of the second epitaxial structure 104 is smaller, making its emission green light, thereby obtaining a monolithic integrated blue-green dual-color display module.

[0111] Continuing from the previous example, continue to refer to Figure 14For S512, a common electrode 305 and a color purification layer are fabricated. The common electrode 305 is provided with openings above the first ohmic contact layer 2041 and the second ohmic contact layer 2042, and is connected to the first ohmic contact layer 2041 and the second ohmic contact layer 2042 to connect the same poles of adjacent light-emitting units. For ease of explanation, in this embodiment, the common electrode 305 is the N pole, and the common electrode 305 is connected to the contact 302 on the leftmost side (in the illustrated direction) of the substrate 301 through a through hole or wire bonding. The material and thickness of the common electrode 305 are not limited in this example. The color purification layer can be a DBR, a filter film, etc., and its function is to achieve band-pass filtering of blue or green light, thereby improving color purity. Among them, a first color purification layer 310 is provided above the first ohmic contact layer 2041. The first color purification layer 310 transmits blue light and has a low transmittance to light of other colors; a second color purification layer 311 is provided above the second ohmic contact layer 2042. The second color purification layer 311 transmits green light and has a low transmittance to light of other colors. In this example, the sizes of the first color purification layer 310 and the second color purification layer 311 are the same as the lower bases of the first epitaxial structure 103 and the second epitaxial structure 104, respectively, to ensure the color filtering effect. The specific preparation method of the color purification layer can be inkjet printing, transfer printing, nanoimprinting, etc., and this embodiment does not limit it.

[0112] See Figure 14 For S513, in order to achieve light pattern optimization, a light pattern adjustment structure 312 is also provided in each light-emitting unit. In this example, the light pattern adjustment structure 312 is in the form of a convex lens and can be configured to suppress the light divergence angle of the light-emitting chip. In practical applications, the light pattern adjustment structure 312 can also be formed into other shapes. The light pattern adjustment structure 312 can form an array, and the preparation method of the light pattern adjustment structure 312 array is not limited and can be nanoimprinting, micro-lens array transfer, hot melt photoresist etching oxide preparation, etc. The light pattern adjustment structure 312 array can use a material with a visible light band transmittance greater than 90% and a visible light band refractive index > 1.30.

[0113] The display module of the above example realizes blue-green dual-color display based on the same epitaxial wafer structure. By preparing the sacrificial layer 308 to selectively grow the epitaxial structure, the damage during the etching process is avoided, and it has a higher radiation efficiency. And by utilizing the difference in the annealing conditions of the first ohmic contact layer 2041 and the second ohmic contact layer 2042, the specific contact resistivity of the first ohmic contact layer 2041 and the second ohmic contact layer 2042 is different, so that under the same driving voltage, the first light-emitting unit 101 and the second light-emitting unit 102 can emit blue light and green light respectively. Its production is simple, and only a unified driving voltage needs to be provided without increasing additional control costs.

[0114] It should be understood that the application of this application is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of this application.

Claims

1. A display module, characterized in that, Comprising: A substrate; A plurality of light-emitting units provided on the substrate, each light-emitting unit including an epitaxial structure and an ohmic contact layer provided on the epitaxial structure; Wherein, the ohmic contact resistance of the ohmic contact layer of at least some of the light-emitting units is different from that of the ohmic contact layer of other light-emitting units, and the epitaxial structure is configured to have a wavelength shift of more than 60 nm under different currents, so that the at least some of the light-emitting units have a different emission wavelength from that of other light-emitting units under the same driving voltage.

2. The display module according to claim 1, wherein The ohmic contact layer of the at least some of the light-emitting units has a different specific contact resistivity or ohmic contact area from that of other ohmic contact layers to form different ohmic contact resistances.

3. The display module according to claim 1, wherein The diffusion depth of the ohmic contact layer of the at least some of the light-emitting units into the epitaxial structure is different from that of other ohmic contact layers.

4. The display module according to claim 3, wherein The material of the ohmic contact layer includes indium tin oxide.

5. The display module according to claim 1, wherein The material of the ohmic contact layer of the at least some of the light-emitting units is different from that of other ohmic contact layers.

6. The display module according to claim 1, wherein The ohmic contact areas of the respective ohmic contact layers are the same.

7. The display module according to claim 1, wherein Each of the light-emitting units further includes at least one of the following structures: A color purification layer provided in the light-emitting direction of the light-emitting unit, configured to selectively block light, and the wavelength range that can pass through it is related to the emission wavelength of the corresponding light-emitting unit; A light pattern adjustment structure provided in the light-emitting direction of the light-emitting unit, configured to adjust the light-emitting pattern of the light-emitting unit; A metal electrode connecting the epitaxial structure and the substrate, and further protruding away from the substrate around the epitaxial structure to form a barrier wall for blocking the lateral light of the light-emitting unit; A current spreading layer provided on the epitaxial structure and on the opposite side of the ohmic contact layer.

8. A manufacturing method of a display module, characterized in that, Comprising: Providing a substrate; Providing a plurality of light-emitting units on the substrate, each light-emitting unit including an epitaxial structure and an ohmic contact layer provided on the epitaxial structure; Wherein, the ohmic contact resistance of the ohmic contact layer of at least some of the light-emitting units is different from that of other ohmic contact layers, and the epitaxial structure is configured to have a wavelength shift of more than 60 nm under different currents, so that the at least some of the light-emitting units have a different emission wavelength from that of other light-emitting units under the same driving voltage.

9. The manufacturing method of the display module according to claim 8, wherein, The step of providing a plurality of light-emitting units on the substrate includes: Providing a plurality of the epitaxial structures on the substrate; Providing the ohmic contact layer on the epitaxial structure, and the ohmic contact layer uses the same material. Among them, the ohmic contact layer of the at least some of the light-emitting units is provided under annealing conditions different from those of the ohmic contact layer of other light-emitting units, so that the ohmic contact layer of the at least some of the light-emitting units has a different specific contact resistivity from that of the ohmic contact layer of other light-emitting units.

10. The manufacturing method of the display module according to claim 9, characterized in that, After providing a plurality of the epitaxial structures on the substrate and before providing the ohmic contact layer on the epitaxial structure, the method further includes the steps of: Providing an insulating material on the epitaxial structure, and the insulating material covers the surface of the epitaxial structure; Removing the insulating material on the surface of the side of the epitaxial structure away from the substrate to completely expose the surface of this side of the epitaxial structure for providing the ohmic contact layer.

11. The manufacturing method of the display module according to claim 10, wherein The substrate includes a circuit layer and a bonding layer disposed on the circuit layer, and the bonding layer is connected to the circuit layer; After the insulating material is disposed on the epitaxial structure and before the insulating material on the surface of the epitaxial structure away from the substrate is removed, the following steps are further included: Patterning the insulating material to form a mask pattern; Etching the bonding layer through the mask pattern so that the bonding layer is divided into metal electrodes corresponding to respective light-emitting units, and each of the metal electrodes remains connected to the circuit layer; during the process of etching the bonding layer, the bonding layer is re-deposited in the etched area to form a barrier wall protruding away from the substrate.

12. A display device, characterized in that, It includes a frame body and a display module as described in any one of claims 1-7 disposed on the frame body.

Images