Micro display device and method for preparing the same

Abstract

The present invention discloses a micro display device and a method for preparing the same. The micro display device comprises a plurality of micro light-emitting units and a plurality of sub-pixel openings corresponding to the plurality of micro light-emitting units; a light conversion layer is disposed in at least some of the sub-pixel openings, and the light conversion layer is used to convert the color of the light emitted by the micro light-emitting units; along the thickness direction of the micro display device, the orthographic projection of the light conversion layer is located outside the orthographic projection of the corresponding micro light-emitting unit; along the direction perpendicular to the thickness direction of the micro display device, the projection of the light conversion layer is located outside the orthographic projection of the corresponding micro light-emitting unit. The present invention can improve the display stability of the micro display device.

Description

Technical Field

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

[0002] Microdisplay devices use microdisplay units to achieve luminous display, such as MicroLED (MicroLight Emitting Diode). Compared with traditional LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode), microdisplay units have greater advantages in brightness, resolution, contrast, energy consumption, service life, response speed and thermal stability.

[0003] In the related art, a monochromatic light-emitting chip can be integrated into a micro-display device as a light source, and quantum dots can be set in the micro-display device as a light conversion layer to achieve full-color display. However, since quantum dots are relatively fragile, the light-emitting chip will seriously affect the stability of the quantum dots, causing the light-emitting performance of the quantum dots to decay, affecting the stability of the display of the micro-display device. Summary of the invention

[0004] The invention provides a micro display device and a preparation method thereof, so as to improve the display stability of the micro display device.

[0005] According to one aspect of the present invention, there is provided a micro display device, the micro display device comprising a plurality of micro light emitting units and a plurality of sub-pixel openings corresponding to the plurality of micro light emitting units one by one;

[0006] A light conversion layer is disposed in at least part of the sub-pixel openings, and the light conversion layer is used to convert the color of the light emitted by the micro-light-emitting unit;

[0007] Along the thickness direction of the micro display device, the orthographic projection of the light conversion layer is located outside the orthographic projection of the corresponding micro light emitting unit;

[0008] Along a direction perpendicular to the thickness direction of the micro display device, the projection of the light conversion layer is located outside the orthographic projection of the corresponding micro light emitting unit.

[0009] Optionally, each of the micro-luminescent units is provided with a first light scattering layer and a second light scattering layer;

[0010] Along the thickness direction of the microdisplay device, the orthographic projection of the first light scattering layer coincides with the orthographic projection of the sub-pixel opening, and the orthographic projection of the second light scattering layer coincides with the orthographic projection of the micro-light-emitting unit; wherein the first light scattering layer is located on the side of the sub-pixel opening away from the light-emitting surface of the microdisplay device, and the second light scattering layer is located on the side of the micro-light-emitting unit close to the light-emitting surface of the microdisplay device; and the sidewall of the first light scattering layer is connected to the sidewall of the second light scattering layer and the corresponding sidewall of the micro-light-emitting unit.

[0011] Optionally, along the thickness direction of the micro display device, the orthographic projection of the micro light-emitting unit surrounds the orthographic projection of the corresponding sub-pixel opening.

[0012] Optionally, the second light scattering layer surrounds the sub-pixel opening to form a side wall of the sub-pixel opening; and the first light scattering layer forms a bottom wall of the sub-pixel opening.

[0013] Optionally, the micro display device further includes a top reflective layer covering the entire surface, and the top reflective layer exposes the sub-pixel opening.

[0014] Optionally, the first light scattering layer is flush with a surface of the second light scattering layer close to a light emitting surface of the micro display device;

[0015] The micro display device further includes a black dam layer, and the black dam layer forms the sub-pixel opening.

[0016] Optionally, a side reflection layer is provided on a side of the micro-luminescent unit and the corresponding second light scattering layer away from the sub-pixel opening.

[0017] Optionally, along the thickness direction of the micro display device, the orthographic projection of the micro light emitting unit is located on one side of the orthographic projection of the corresponding sub-pixel opening.

[0018] Optionally, the micro display device further includes a side reflection layer surrounding the micro light emitting unit, the first light scattering layer and the second light scattering layer.

[0019] Optionally, along the thickness direction of the micro display device, the top surface of the second light scattering layer is located on a side of the top surface of the first light scattering layer close to the light emitting surface of the micro display device; the top surface of the first light scattering layer serves as a bottom wall of the sub-pixel opening; part of the side surface of the second light scattering layer and part of the side surface of the side reflection layer serve as side walls of the sub-pixel opening;

[0020] The micro display device further includes a top reflective layer which entirely covers and exposes the sub-pixel opening.

[0021] Optionally, the first light scattering layer is flush with a surface of the second light scattering layer close to a light emitting surface of the micro display device;

[0022] The micro display device further includes a black dam layer, and the black dam layer forms the sub-pixel opening.

[0023] Optionally, the light conversion layer is disposed in part of the sub-pixel openings, and light scattering particles are disposed in the remaining part of the sub-pixel openings.

[0024] Optionally, the micro display device further comprises a substrate and a total reflection layer; the total reflection layer is arranged on a side of the micro light-emitting unit away from the light-emitting surface of the micro display device; the substrate is arranged on a side of the total reflection layer away from the micro display device.

[0025] According to another aspect of the present invention, there is provided a method for preparing a micro display device, comprising:

[0026] forming a plurality of micro-light-emitting units and a plurality of sub-pixel openings corresponding to the plurality of micro-light-emitting units one by one;

[0027] A light conversion layer is formed in at least a portion of the sub-pixel opening; wherein, along the thickness direction of the microdisplay device, the orthographic projection of the light conversion layer is located outside the orthographic projection of the corresponding micro-light-emitting unit; along the direction perpendicular to the thickness direction of the microdisplay device, the projection of the light conversion layer is located outside the orthographic projection of the corresponding micro-light-emitting unit.

[0028] The technical solution of the embodiment of the present invention adopts a micro display device including a plurality of micro light-emitting units and a plurality of sub-pixel openings corresponding to the plurality of micro light-emitting units; a light conversion layer is arranged in at least part of the sub-pixel openings, and the light conversion layer is used to convert the color of the light emitted by the micro light-emitting unit; along the thickness direction of the micro display device, the orthographic projection of the light conversion layer is located outside the orthographic projection of the corresponding micro light-emitting unit; along the direction perpendicular to the thickness direction of the micro display device, the projection of the light conversion layer is located outside the orthographic projection of the corresponding micro light-emitting unit. The light conversion layer and the corresponding micro light-emitting unit have a certain misalignment in the horizontal direction and the vertical direction, thereby ensuring that the outgoing light of the micro light-emitting unit will not directly enter the light conversion layer, and the micro light-emitting unit and the corresponding light conversion layer are not in direct contact and the distance is also far, thereby reducing the influence of the high brightness and high heat of the micro light-emitting unit on the stability of the light conversion layer, thereby improving the display stability of the micro display device.

[0029] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A schematic structural diagram of a micro display device provided by an embodiment of the present invention;

[0032] Figure 2 A top view of a micro display device provided by an embodiment of the present invention;

[0033] Figure 3 A schematic structural diagram of another micro display device provided by an embodiment of the present invention;

[0034] Figure 4 A top view of another micro display device provided by an embodiment of the present invention;

[0035] Figure 5 A schematic structural diagram of another micro display device provided by an embodiment of the present invention;

[0036] Figure 6 A schematic structural diagram of another micro display device provided by an embodiment of the present invention;

[0037] Figure 7 A top view of another micro display device provided by an embodiment of the present invention;

[0038] Figure 8 A schematic structural diagram of another micro display device provided by an embodiment of the present invention;

[0039] Fig. 9 A flow chart of a method for preparing a micro display device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the 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 ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0041] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0042] Just as the problem of the light-emitting chip affecting the quantum dots exists in the micro-display device in the related art, the inventors have found through extensive research that the reason for this technical problem is that the light-emitting chip in the related art is in direct contact with the quantum dots, or the emitted light of the light-emitting chip directly enters the quantum dots, or the distance between the light-emitting chip and the quantum dots is too close. The light-emitting chip has the characteristics of high heat and high brightness when emitting light, and the high heat and high brightness of the light-emitting chip will seriously affect the stability of the quantum dots, thereby causing the light-emitting performance of the quantum dots to decay.

[0043] In view of the above technical problems, the present invention proposes the following solutions:

[0044] Figure 1 A schematic diagram of the structure of a micro display device provided by an embodiment of the present invention, Figure 2 A top view of a micro display device provided by an embodiment of the present invention, Figure 2 and Figure 1 Correspondence, reference Figure 1 and Figure 2 The micro display device includes a plurality of micro light-emitting units 13 and a plurality of sub-pixel openings Gap corresponding to the plurality of micro light-emitting units; a light conversion layer QD is disposed in at least part of the sub-pixel openings Gap, and the light conversion layer QD is used to convert the color of the light emitted by the micro light-emitting unit 13; along the thickness direction Y of the micro display device, the projection of the light conversion layer QD is located outside the orthographic projection of the corresponding micro light-emitting unit 13; along the direction perpendicular to the thickness direction Y of the micro display device, the projection of the light conversion layer QD is located outside the orthographic projection of the corresponding micro light-emitting unit 13.

[0045] Specifically, the micro-light-emitting unit 13 is, for example, a MicroLED, which may specifically include an N-type semiconductor layer, a light-emitting layer, a P-type semiconductor layer, and the like. The micro-light-emitting unit 13 may emit light of a set color, for example, blue light. The light conversion layer QD is, for example, a quantum dot layer. The multiple micro-light-emitting units in the micro display device may be divided into multiple first micro-light-emitting units, multiple second micro-light-emitting units, and multiple third micro-light-emitting units, and the difference between different micro-light-emitting units is that the structures in the corresponding sub-pixel openings Gap are different, so that the light-emitting colors of different micro-light-emitting units are different. Exemplarily, the first micro-light-emitting unit may be a micro-light-emitting unit that emits green light, and the light conversion layer QD in the first micro-light-emitting unit is QDG that converts blue light to green light; the second micro-light-emitting unit may be a micro-light-emitting unit that emits red light, and the light conversion layer QD in the second micro-light-emitting unit is QDR that converts blue light to red light; the third micro-light-emitting unit may be a micro-light-emitting unit that emits blue light, and the light conversion layer for color conversion may not be provided in the sub-pixel opening corresponding to the third micro-light-emitting unit. Through the coordination of three kinds of red, green and blue micro-light-emitting units, such as a red sub-pixel, a blue sub-pixel and a green sub-pixel can form a pixel, the pixel can emit light of any color, so that the micro-display device can achieve full-color display.

[0046] It should be noted that the shape of the sub-pixel opening Gap and the shape of the micro-light-emitting unit 13 can be set as required and is not limited to Figure 1 and Figure 2 In addition, the sub-pixel opening Gap can be opened on a related film layer, and the related film layer will be described later, which will not be described here.

[0047] In the related art, the light emitting chip is in direct contact with the quantum dot, or the light emitted by the light emitting chip directly enters the quantum dot, or the distance between the light emitting chip and the quantum dot is too close. Figure 1 and Figure 2As shown, along the thickness direction Y of the micro display device, the orthographic projection of the light conversion layer QD is located outside the orthographic projection of the corresponding micro light-emitting unit 13. That is to say, in the horizontal direction, the light conversion layer QD and the micro light-emitting unit 13 do not overlap, and there is a certain misalignment. Among them, the horizontal direction is the direction in the plane formed by the first direction X and the second direction Z, and the first direction X, the second direction Z and the thickness direction Y are perpendicular to each other. The outgoing light of the micro light-emitting unit 13 along the thickness direction of the micro display device will not directly enter the light conversion layer QD. Along the direction perpendicular to the thickness direction Y, the orthographic projection of the light conversion layer QD is located outside the orthographic projection of the corresponding micro light-emitting unit 13, that is to say, in the vertical direction, the light conversion layer QD and the micro light-emitting unit 13 do not overlap, and there is a certain misalignment. In other words, there is a certain misalignment between the light conversion layer QD and the corresponding micro-light-emitting unit 13 in the horizontal and vertical directions, thereby ensuring that the output light of the micro-light-emitting unit 13 will not directly enter the light conversion layer QD, and the micro-light-emitting unit 13 and the corresponding light conversion layer QD are not in direct contact and are far away, thereby reducing the impact of the high brightness and high heat of the micro-light-emitting unit 13 on the stability of the light conversion layer QD, thereby improving the display stability of the micro-display device.

[0048] The technical solution of this embodiment adopts a micro-display device including a plurality of micro-light-emitting units and a plurality of sub-pixel openings corresponding to the plurality of micro-light-emitting units; a light conversion layer is arranged in at least part of the sub-pixel openings, and the light conversion layer is used to convert the color of the light emitted by the micro-light-emitting unit; along the thickness direction of the micro-display device, the orthographic projection of the light conversion layer is located outside the orthographic projection of the corresponding micro-light-emitting unit; along the direction perpendicular to the thickness direction of the micro-display device, the projection of the light conversion layer is located outside the orthographic projection of the corresponding micro-light-emitting unit. The light conversion layer and the corresponding micro-light-emitting unit are misaligned in both the horizontal and vertical directions, thereby ensuring that the emitted light of the micro-light-emitting unit will not directly enter the light conversion layer, and the micro-light-emitting unit and the corresponding light conversion layer are not in direct contact and the distance is also far, thereby reducing the influence of the high brightness and high heat of the micro-light-emitting unit on the stability of the light conversion layer, thereby improving the display stability of the micro-display device.

[0049] In some embodiments, optionally, Figure 3 A schematic diagram of the structure of another micro display device provided by an embodiment of the present invention, Figure 4 A top view of another micro display device provided by an embodiment of the present invention, Figure 4 and Figure 3 Correspondence, reference Figure 3 and Figure 4Each micro-light-emitting unit 13 is provided with a first light scattering layer 15 and a second light scattering layer 14. Along the thickness direction Y of the micro-display device, the orthographic projection of the first light scattering layer 15 coincides with the orthographic projection of the sub-pixel opening, and the orthographic projection of the second light scattering layer 14 coincides with the orthographic projection of the micro-light-emitting unit 13; wherein, the first light scattering layer 15 is located on the side of the sub-pixel opening away from the light-emitting surface of the micro-display device, and the second light scattering layer 14 is located on the side of the micro-light-emitting unit 13 close to the light-emitting surface of the micro-display device; the side wall of the first light scattering layer 15 is connected to the side wall of the second light scattering layer 14 and the side wall of the micro-light-emitting unit 13.

[0050] Specifically, in the above-mentioned embodiment, the light emitted by the micro-luminescent unit 13 along the thickness direction perpendicular to the micro-display device has a high energy. Although this part of the light is not directly incident on the light conversion layer, some light at an angle to the thickness direction Y may be directly incident on the light conversion layer QD, and this part of the light still has a high intensity. In this embodiment, by providing the first light scattering layer 15 and the second light scattering layer 14, the light emitted by the micro-luminescent unit 13 will enter the corresponding light conversion layer QD after being scattered by the first light scattering layer 15 and / or the second light scattering layer 14, and the light after multiple scattering will be evenly dispersed throughout the light conversion layer QD, thereby further reducing the influence of the strong light emitted by the micro-luminescent unit on the light conversion layer QD.

[0051] Further optionally, in the above embodiment, the first light scattering layer 15 and the second light scattering layer 14 are an integrated structure. The first light scattering layer 15 and the second light scattering layer 14 can be any film layer with scattering function, preferably a photoresist layer doped with organic or inorganic scattering particles.

[0052] Optionally, continue to refer to Figure 3 and Figure 4 , along the thickness direction Y of the micro display device, the orthographic projection of the micro light-emitting unit 13 surrounds the orthographic projection of the corresponding sub-pixel opening Gap.

[0053] Specifically, in this embodiment, the micro-light-emitting unit 13 is a hollow structure, and the shape of the micro-light-emitting unit 13 can be circular, rectangular, or any other polygonal shape. The sub-pixel opening is located at the corresponding hollow structure position, that is, the light conversion layer QD is located at the corresponding hollow structure position, so the light conversion layer QD can receive the light emitted by the micro-light-emitting unit 13 from all directions, so that the light received by the light conversion layer QD is more uniform, and the light output of the sub-pixel is more uniform.

[0054] Further optionally, along the thickness direction Y of the micro display device, the orthographic projection of the light conversion layer QD coincides with the orthographic projection of the corresponding sub-pixel opening Gap; the orthographic projection of the sub-pixel opening Gap coincides with the orthographic projection of the hollow structure of the corresponding micro light-emitting unit 13.

[0055] Further optionally, along the first direction X and the second direction Z, the distance between the sub-pixel opening and the edge of the micro-luminescent unit 13 away from the sub-pixel opening is equal everywhere. Thus, the intensity of light emitted from the micro-luminescent unit 13 toward the light conversion layer QD from all directions is closer, which makes the light emitted by the micro-luminescent unit 13 received by the light conversion layer QD from all directions more uniform, and the light emission of the sub-pixel is more uniform.

[0056] Further optionally, in some embodiments, a light conversion layer QD is disposed in a portion of the sub-pixel openings Gap, and a light scattering particle layer 19 is disposed in the remaining portion of the sub-pixel openings.

[0057] Specifically, the light scattering particle layer 19 can be a photoresist doped with scattering particles, which can change the propagation path of light, thereby improving the light extraction rate. In this embodiment, the light color at the light scattering particle layer 19 is the same as the light color of the micro-luminescent unit 13.

[0058] Optionally, continue to refer to Figure 3 and Figure 4 The second light scattering layer 14 surrounds the sub-pixel opening Gap to form the side wall of the sub-pixel opening Gap; the first light scattering layer 15 forms the bottom wall of the sub-pixel opening Gap.

[0059] Specifically, in the present embodiment, the sub-pixel opening Gap is formed on the integrated structure composed of the first light scattering layer 15 and the second light scattering layer 14. The integrated structure of the first light scattering layer 15 and the second light scattering layer 14 may be formed first, and then the sub-pixel opening Gap is etched. In this way, the side wall of the light conversion layer QD will contact the second light scattering layer 14, and the bottom wall of the light conversion layer QD will contact the first light scattering layer 15. In other words, the side wall and the bottom wall of the light conversion layer QD can both receive light scattered from the light scattering layer, thereby improving the light extraction efficiency.

[0060] Optionally, continue to refer to Figure 3 and Figure 4 The micro display device further includes a top reflective layer 17 covering the entire surface, and the top reflective layer 17 exposes the sub-pixel opening.

[0061] Specifically, the top reflection layer 17 covers the second light scattering layer 14 and can be in contact with the second light scattering layer 14. The top reflection layer 17 is, for example, a metal layer or a distributed Bragg reflection layer. The metal layer can be formed of a metal with high reflectivity such as Al, Ag, Ti, Mg, etc. The distributed Bragg reflection layer is also called a distributed Bragg reflector (DBR), which is a periodic structure composed of two materials with different refractive indices alternately stacked. By setting the top reflection layer 17, after the light in the second light scattering layer 14 reaches the top surface of the second light scattering layer 14, it is reflected by the top reflection layer 17 and finally reaches the light conversion layer QD, which can further improve the light conversion efficiency of the light conversion layer QD.

[0062] Optionally, continue to refer to Figure 3 A side reflection layer 16 is provided on a side of the micro-luminescent unit 13 and the corresponding second light scattering layer 14 away from the sub-pixel opening Gap.

[0063] Specifically, the overall structure composed of the micro-light-emitting unit 13, the corresponding first light scattering layer 15, the corresponding second light scattering layer 14, and the corresponding structure in the sub-pixel opening (such as the light conversion layer QD) can be understood as a sub-pixel. In this embodiment, a side reflection layer 16 is provided at the side wall of the sub-pixel, which can isolate the light crosstalk between different sub-pixels. In other words, when the light emitted by the sub-pixel reaches the side wall of the sub-pixel, it will be reflected by the side reflection layer 16 and will not be incident on other sub-pixels, thereby avoiding the generation of light crosstalk between different sub-pixels. The side reflection layer 16 is, for example, a metal layer or a distributed Bragg reflection layer, and the metal layer can be formed of a metal with high reflectivity such as Al, Ag, Ti, Mg, etc.

[0064] Optionally, continue to refer to Figure 3 The micro display device further includes a substrate 11 and a total reflection layer 12; the total reflection layer 12 is arranged on a side of the micro light-emitting unit 13 away from the light-emitting surface of the micro display device; the substrate 11 is arranged on a side of the total reflection layer 12 away from the micro display device.

[0065] Specifically, the top surface of the micro-light-emitting unit 13 is a surface close to the light-emitting surface of the micro-display device, and the substrate 11 is disposed on one side of the bottom surface of the micro-light-emitting unit 13. The substrate 11 can play a role in supporting each film layer, and the substrate 11 can be a substrate including a pixel circuit. The total reflection layer 12 can be a metal layer or a Bragg reflection layer, which plays an effect of reflecting the light emitted by the sub-pixel to the light-emitting surface side of the micro-display device, thereby further improving the light extraction efficiency.

[0066] In some other embodiments, optionally, Figure 5 A schematic diagram of the structure of another micro display device provided in an embodiment of the present invention, referring to Figure 5The first light scattering layer 15 and the second light scattering layer 14 are flush with each other on a side close to the light emitting surface of the micro display device; the micro display device further comprises a black dam layer 18, which forms a sub-pixel opening Gap.

[0067] Specifically, in this embodiment, the first light scattering layer 15 and the second light scattering layer 14 are flat surfaces close to the light emitting surface of the micro display device, and the black dam layer 18 covers the entire surface of the second light scattering layer 14. A whole layer of black dam layer may be formed first, and then the sub-pixel opening Gap is formed by etching. The black dam layer 18 has a light absorption effect. After the light emitted by the micro light-emitting unit 13 is scattered by the second light scattering layer 14, when it is incident on the surface of the black dam layer 18, it will be absorbed by the black dam layer 18, so that it will not affect other sub-pixels, and will not cause light crosstalk problems.

[0068] In other embodiments, a top reflection layer 17 is disposed between the black bank layer 18 and the second light scattering layer 14 .

[0069] A top reflection layer 17 is arranged between the black dam layer 18 and the second light scattering layer 14. Part of the light emitted by the first light scattering layer 15 and the second light scattering layer 14 is reflected back to the first light scattering layer 15 and the second light scattering layer 14 through the top reflection layer 17. A small amount of light passes through the top reflection layer 17 and enters the black dam layer 18 and is absorbed by the black dam layer 18. The top reflection layer 17 and the black dam layer 18 cooperate to ensure the best luminous efficiency while avoiding light crosstalk.

[0070] Further optionally, if Figure 5 As shown, a side reflection layer 16 is disposed on the side of the micro-light-emitting unit 13 and the corresponding second light scattering layer 14 away from the sub-pixel opening Gap.

[0071] Specifically, in this embodiment, a side reflection layer 16 is provided at the side wall of the sub-pixel, which can have the effect of isolating light crosstalk between different sub-pixels. That is to say, when the light emitted by the sub-pixel reaches the side wall of the sub-pixel, it will be reflected by the side reflection layer 16 and will not be incident on other sub-pixels, thereby avoiding light crosstalk between different sub-pixels. The side reflection layer 16 is, for example, a metal layer or a distributed Bragg reflection layer, and the metal layer can be formed of a metal with high reflectivity such as Al, Ag, Ti, Mg, etc.

[0072] Optionally, continue to refer to Figure 5 The micro display device further includes a substrate 11 and a total reflection layer 12; the total reflection layer 12 is arranged on a side of the micro light-emitting unit 13 away from the light-emitting surface of the micro display device; the substrate 11 is arranged on a side of the total reflection layer 12 away from the micro display device.

[0073] Specifically, the top surface of the micro-light-emitting unit 13 is a surface close to the light-emitting surface of the micro-display device, and the substrate 11 is disposed on one side of the bottom surface of the micro-light-emitting unit 13. The substrate 11 can play a role in supporting each film layer, and the substrate 11 can be a substrate including a pixel circuit. The total reflection layer 12 can be a metal layer or a Bragg reflection layer, which plays an effect of reflecting the light emitted by the sub-pixel to the light-emitting surface side of the micro-display device, thereby further improving the light extraction efficiency.

[0074] In some other embodiments, optionally, Figure 6 A schematic diagram of the structure of another micro display device provided by an embodiment of the present invention, Figure 7 A top view of another micro display device provided by an embodiment of the present invention, Figure 7 and Figure 6 Correspondence, reference Figure 6 and Figure 7 Along the thickness direction Y of the micro display device, the orthographic projection of the micro light emitting unit 13 is located on one side of the corresponding sub-pixel opening Gap.

[0075] Specifically, Figure 3 Unlike the micro-light-emitting unit 13 surrounding the sub-pixel opening Gap shown in the figure, the micro-light-emitting unit 13 in this embodiment is located on one side of the sub-pixel opening Gap. In this arrangement, the area of ​​the sub-pixel formed by the micro-light-emitting unit 13, the first light scattering layer 15, the second light scattering layer 14, and the light conversion layer or light scattering particle layer in the sub-pixel opening Gap is smaller, and more sub-pixels can be arranged when the area of ​​the micro-display device is the same, that is, the micro-display device can have a higher resolution.

[0076] Further optionally, reference Figure 6 and Figure 7 The micro display device further includes a side reflection layer 16 surrounding the micro light emitting unit 13 , the first light scattering layer 15 and the second light scattering layer 14 .

[0077] Specifically, the micro-luminescent unit 13, the corresponding first light scattering layer 15, the corresponding second light scattering layer 14 and the light conversion layer or light scattering particle layer in the corresponding sub-pixel opening constitute a sub-pixel, and the side reflection layer 16 surrounds the side wall of each sub-pixel. The side reflection layer 16 is provided at the side wall of the sub-pixel, which can isolate the light crosstalk between different sub-pixels. In other words, when the light emitted by the sub-pixel reaches the side wall of the sub-pixel, it will be reflected by the side reflection layer 16 and will not be incident on other sub-pixels, thereby avoiding the generation of light crosstalk between different sub-pixels. The side reflection layer 16 is, for example, a metal layer or a distributed Bragg reflection layer, and the metal layer can be formed of a metal with high reflectivity such as Al, Ag, Ti, Mg, etc.

[0078] Further optionally, reference Figure 6, along the thickness direction Y of the micro display device, the top surface of the second light scattering layer 14 is located on the side of the top surface of the first light scattering layer 15 close to the light emitting surface of the micro display device; the top surface of the first light scattering layer 15 serves as the bottom wall of the sub-pixel opening Gap; part of the side surface of the second light scattering layer 14 and part of the side surface of the side reflection layer serve as the side wall of the sub-pixel opening; the micro display device further comprises a top reflection layer 17 which entirely covers and exposes the sub-pixel opening Gap of the micro display device.

[0079] Specifically, in this embodiment, the side wall of the sub-pixel opening Gap is composed of the side reflection layer 16 and the side wall of the second light scattering layer 14. In other words, the structure in the sub-pixel opening Gap, that is, the side wall of the light conversion layer QD or the light scattering particle layer 19 is in contact with the second light scattering layer 14. The side wall and the bottom wall of the light conversion layer QD can receive light scattered from the light scattering layer, thereby improving the light extraction efficiency.

[0080] In addition, the top reflection layer 17 covers the second light scattering layer 14 and can be in contact with the second light scattering layer 14. The top reflection layer 17 is, for example, a metal layer or a distributed Bragg reflection layer. The metal layer can be formed of a metal with high reflectivity such as Al, Ag, Ti, Mg, etc. The distributed Bragg reflection layer is also called a distributed Bragg reflector, which is a periodic structure composed of two materials with different refractive indices alternately stacked. By providing the top reflection layer 17, after the light in the second light scattering layer 14 reaches the top surface of the second light scattering layer 14, it is reflected by the top reflection layer 17 and finally reaches the light conversion layer QD, which can further improve the light conversion efficiency of the light conversion layer QD.

[0081] Optionally, continue to refer to Figure 6 The micro display device further includes a substrate 11 and a total reflection layer 12; the total reflection layer 12 is arranged on a side of the micro light-emitting unit 13 away from the light-emitting surface of the micro display device; the substrate 11 is arranged on a side of the total reflection layer 12 away from the micro display device.

[0082] Specifically, the top surface of the micro-light-emitting unit 13 is a surface close to the light-emitting surface of the micro-display device, and the substrate 11 is disposed on one side of the bottom surface of the micro-light-emitting unit 13. The substrate 11 can play a role in supporting each film layer, and the substrate 11 can be a substrate including a pixel circuit. The total reflection layer 12 can be a metal layer or a Bragg reflection layer, which plays an effect of reflecting the light emitted by the sub-pixel to the light-emitting surface side of the micro-display device, thereby further improving the light extraction efficiency.

[0083] In some other embodiments, optionally, Figure 8 As shown, Figure 8A schematic diagram of another micro display device provided by an embodiment of the present invention is shown in FIG. The first light scattering layer 15 is flush with a side of the second light scattering layer 14 close to the light emitting surface of the micro display device; the micro display device further includes a black dam layer 18, which forms a sub-pixel opening Gap.

[0084] Specifically, in this embodiment, a whole black dam layer may be formed first, and then the sub-pixel opening Gap may be formed by etching. The black dam layer 18 has a light absorption effect. The light emitted by the micro-luminescent unit 13 is scattered by the second light scattering layer 14 and incident on the surface of the black dam layer 18. The light will be absorbed by the black dam layer 18, so that other sub-pixels will not be affected, and no light crosstalk problem will occur.

[0085] In other embodiments, a top reflection layer 17 is disposed between the black bank layer 18 and the second light scattering layer 14 .

[0086] Optionally, continue to refer to Figure 8 The micro display device further includes a substrate 11 and a total reflection layer 12; the total reflection layer 12 is arranged on a side of the micro light-emitting unit 13 away from the light-emitting surface of the micro display device; the substrate 11 is arranged on a side of the total reflection layer 12 away from the micro display device.

[0087] Specifically, the top surface of the micro-light-emitting unit 13 is a surface close to the light-emitting surface of the micro-display device, and the substrate 11 is disposed on one side of the bottom surface of the micro-light-emitting unit 13. The substrate 11 can play a role in supporting each film layer, and the substrate 11 can be a substrate including a pixel circuit. The total reflection layer 12 can be a metal layer or a Bragg reflection layer, which plays an effect of reflecting the light emitted by the sub-pixel to the light-emitting surface side of the micro-display device, thereby further improving the light extraction efficiency.

[0088] The present invention also provides a method for preparing a micro display device, such as Fig. 9 As shown, Fig. 9 A flowchart of a method for preparing a micro display device provided in an embodiment of the present invention. The method for preparing a micro display device comprises:

[0089] Step S301, forming a plurality of micro-light-emitting units and a plurality of sub-pixel openings corresponding to the plurality of micro-light-emitting units one by one;

[0090] Specifically, an epitaxial wafer may be provided first, and then the epitaxial wafer may be patterned to form a plurality of micro-light-emitting units. The sub-pixel opening may be formed on other film layers.

[0091] Step S302, forming a light conversion layer in at least a portion of the sub-pixel opening; wherein, along the thickness direction of the microdisplay device, the orthographic projection of the light conversion layer is located outside the orthographic projection of the corresponding micro-light-emitting unit; along the direction perpendicular to the thickness direction of the microdisplay device, the projection of the light conversion layer is located outside the orthographic projection of the corresponding micro-light-emitting unit.

[0092] Specifically, the specific structure and working principle of the sub-pixel opening and the micro-light-emitting unit can refer to the description of the micro-display device in the present invention, which will not be repeated here.

[0093] In the micro-display device prepared by the preparation method adopted in the present embodiment, the light conversion layer and the corresponding micro-light-emitting unit are misaligned to a certain extent in the horizontal and vertical directions, thereby ensuring that the output light of the micro-light-emitting unit does not directly enter the light conversion layer. The micro-light-emitting unit and the corresponding light conversion layer are not in direct contact and the distance is also far, thereby reducing the influence of the high brightness and high heat of the micro-light-emitting unit on the stability of the light conversion layer, thereby improving the display stability of the micro-display device.

[0094] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0095] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A micro display device, characterized in that: The micro display device includes a plurality of micro light emitting units and a plurality of sub-pixel openings corresponding to the plurality of micro light emitting units one by one; A light conversion layer is disposed in at least part of the sub-pixel openings, and the light conversion layer is used to convert the color of the light emitted by the micro-light-emitting unit; Along the thickness direction of the micro display device, the orthographic projection of the light conversion layer is located outside the orthographic projection of the corresponding micro light emitting unit; Along a direction perpendicular to the thickness direction of the micro display device, the projection of the light conversion layer is located outside the orthographic projection of the corresponding micro light emitting unit; Each of the micro-luminescent units is correspondingly provided with a first light scattering layer and a second light scattering layer; Along the thickness direction of the micro display device, the orthographic projection of the first light scattering layer coincides with the orthographic projection of the sub-pixel opening, and the orthographic projection of the second light scattering layer coincides with the orthographic projection of the micro light emitting unit; wherein the first light scattering layer is located on the side of the sub-pixel opening away from the light emitting surface of the micro display device, and the second light scattering layer is located on the side of the micro light emitting unit close to the light emitting surface of the micro display device; the side wall of the first light scattering layer is connected to the side wall of the second light scattering layer and the corresponding side wall of the micro light emitting unit; Along the thickness direction of the micro display device, the orthographic projection of the micro light-emitting unit surrounds the orthographic projection of the corresponding sub-pixel opening; the second light scattering layer surrounds the sub-pixel opening to form the side wall of the sub-pixel opening; and the first light scattering layer forms the bottom wall of the sub-pixel opening.

2. The micro display device according to claim 1, characterized in that: The micro display device further includes a top reflective layer covering the entire surface, wherein the top reflective layer exposes the sub-pixel opening.

3. The micro display device according to claim 1, characterized in that: A side reflection layer is provided on a side of the micro-luminescent unit and the corresponding second light scattering layer away from the sub-pixel opening.

4. The micro display device according to claim 1, characterized in that: The light conversion layer is disposed in a portion of the sub-pixel openings, and light scattering particles are disposed in the remaining portion of the sub-pixel openings.

5. The micro display device according to claim 1, characterized in that: The micro display device further comprises a substrate and a total reflection layer; the total reflection layer is arranged on a side of the micro light emitting unit away from the light emitting surface of the micro display device; the substrate is arranged on a side of the total reflection layer away from the micro display device.

6. A method for preparing a micro display device, characterized in that: include: forming a plurality of micro-light-emitting units and a plurality of sub-pixel openings corresponding to the plurality of micro-light-emitting units one by one; A light conversion layer is formed in at least part of the sub-pixel opening; wherein, along the thickness direction of the micro-display device, the orthographic projection of the light conversion layer is located outside the orthographic projection of the corresponding micro-light-emitting unit; along the direction perpendicular to the thickness direction of the micro-display device, the projection of the light conversion layer is located outside the orthographic projection of the corresponding micro-light-emitting unit; each of the micro-light-emitting units is provided with a first light scattering layer and a second light scattering layer; along the thickness direction of the micro-display device, the orthographic projection of the first light scattering layer coincides with the orthographic projection of the sub-pixel opening, and the orthographic projection of the second light scattering layer coincides with the orthographic projection of the micro-light-emitting unit; wherein, the first light scattering layer is located on a side of the sub-pixel opening away from the light-emitting surface of the micro-display device, and the second light scattering layer is located on a side of the micro-light-emitting unit close to the light-emitting surface of the micro-display device; the side wall of the first light scattering layer is connected to the side wall of the second light scattering layer and the side wall of the corresponding micro-light-emitting unit; Along the thickness direction of the micro display device, the orthographic projection of the micro light-emitting unit surrounds the orthographic projection of the corresponding sub-pixel opening; the second light scattering layer surrounds the sub-pixel opening to form the side wall of the sub-pixel opening; and the first light scattering layer forms the bottom wall of the sub-pixel opening.

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