Miniature light emitting diode display and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor devices, and discloses a micro light-emitting diode display and a preparation method thereof. The micro light emitting diode display comprises a substrate, a first LED unit layer and a second LED unit layer. The first LED unit layer is bonded on the substrate and comprises a first passivation layer and a plurality of first LED units. The first passivation layer is located on the surface, away from the substrate side, of the first LED unit layer and exposes the surfaces, away from the substrate side, of the multiple first LED units. And the first passivation layer at least covers the side surfaces of the plurality of first LED units. The second LED unit layer is bonded on the first LED unit layer and comprises a plurality of second LED units and filling and leveling layers located between the adjacent second LED units. And the filling and leveling layer is bonded with the first passivation layer. Wherein the plurality of first LED units and the plurality of second LED units are electrically connected with the substrate respectively. According to the invention, the passivation layer is used as a processing position reference, the LED unit is protected and bonding is realized, the processing difficulty and cost are reduced, and the yield is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of semiconductor devices, and specifically relates to a micro light emitting diode display and a method for preparing the same. Background Art

[0002] There are more and more application scenarios for display technology based on semiconductor devices, such as wearable devices, virtual reality (VR) / augmented reality (AR) devices, etc. However, the size of micro-LED displays is relatively large, which limits the number of pixels that can be integrated into the display screens of small wearable devices such as AR glasses, affecting the resolution and display effect of the devices.

[0003] In the related art, a micro display module and a preparation method thereof are disclosed (CN119546027A), wherein the micro display module includes at least two stacked pixel layers bonded to the same side of a driving substrate. Specifically, the first pixel layer is bonded to the driving substrate through a first wiring layer, and the first pixel layer is bonded to the second pixel layer through a second wiring layer and a third wiring layer. The structure of the micro display module in the related art is complex, which makes the size of the micro display module relatively large, and the processing technology is difficult, resulting in increased costs and reduced overall yield. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems existing in the related art.

[0005] Therefore, a first aspect of the present application provides a micro light emitting diode display.

[0006] A second aspect of the present application provides a method for preparing a micro light emitting diode display.

[0007] According to a first aspect of an embodiment of the present application, a micro light emitting diode display is proposed, comprising: a substrate; a first LED unit layer, bonded to the substrate, comprising a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on a surface of the first LED unit layer facing away from the substrate side, and exposes a plurality of first LED units on a surface facing away from the substrate side; and the first passivation layer also covers at least the side surfaces of the plurality of first LED units; a second LED unit layer, bonded to the first LED unit layer, comprising a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units, the filling layer being bonded to the first passivation layer; wherein the plurality of first LED units and the plurality of second LED units are electrically connected to the substrate, respectively, to achieve separate driving.

[0008] In a possible implementation of the first aspect, the substrate includes a plurality of first contacts, and the first LED unit layer also includes: a planarization layer, which is arranged on the side of the first passivation layer facing the substrate and bonded to the substrate; a first conductive protrusion, one end of the first conductive protrusion is electrically connected to the first LED unit, and the other end is bonded and electrically connected to the corresponding first contact.

[0009] In a possible implementation of the first aspect, the first LED unit layer also includes: a first electrode layer, which is arranged on a side of the first passivation layer away from the first LED unit, and is surrounded by a side of the first LED unit and a side facing the substrate; and the first electrode layer covers a surface of the first LED unit facing the substrate and not covered by the first passivation layer, and the first electrode layer reflects light emitted by the first LED unit.

[0010] In a possible implementation of the first aspect, the second LED unit layer also includes: a second passivation layer, which is arranged on the surface of the filling layer away from the substrate side and exposes the surfaces of the plurality of second LED units away from the substrate side; and the second passivation layer also covers at least the side surfaces of the plurality of second LED units.

[0011] In a possible implementation of the first aspect, the second LED unit layer also includes: a second electrode layer, which is arranged on a side of the second passivation layer away from the second LED unit, and is surrounded by a side of the second LED unit and a side facing the substrate; and the second electrode layer covers a surface of the second LED unit facing the substrate and not covered by the second passivation layer, and the second electrode layer reflects light emitted by the second LED unit.

[0012] In a possible implementation of the first aspect, the micro light emitting diode display further includes: a conductive column vertically penetrating the first LED unit layer, one end of the conductive column is electrically connected to the substrate, and the other end of the conductive column is electrically connected to the corresponding second LED unit.

[0013] In a possible implementation manner of the first aspect, the second LED unit layer further includes: a second conductive protrusion, and the second conductive protrusion is electrically connected to the second LED unit; wherein the conductive column is electrically connected to the second LED unit through the second conductive protrusion.

[0014] In a possible implementation manner of the first aspect, a surface area of ​​a side of the second conductive protrusion bonding to the conductive pillar is larger than a surface area of ​​a side connected to the second electrode layer.

[0015] In a possible implementation of the first aspect, the first LED unit and the second LED unit respectively include a first doped semiconductor layer, an active layer, and a second doped semiconductor layer that are stacked, and the first doped semiconductor layer is close to the substrate; the surface of the second doped semiconductor layer of the first LED unit facing away from the substrate is flush with the surface of the first passivation layer facing away from the substrate; the surface of the second doped semiconductor layer of the second LED unit facing away from the substrate is flush with the surface of the second passivation layer facing away from the substrate.

[0016] In a possible implementation of the first aspect, the substrate includes at least one second contact, and the micro light emitting diode display also includes: a common electrode layer, electrically connected to the surface of the first LED unit and the second LED unit facing away from the substrate, and the common electrode layer is electrically connected to the second contact.

[0017] In a possible implementation of the first aspect, the micro light emitting diode display further includes: a plurality of color conversion units, which are arranged at intervals on a side of the second LED unit layer away from the substrate and are located on part of the first LED unit or part of the second LED unit, the color conversion unit being used to convert a first color light emitted by the first LED unit or a second color light emitted by the second LED unit into a third color light, and the first color light, the second color light and the third color light are different; wherein at least one first LED unit, at least one adjacent second LED unit and at least one adjacent color conversion unit constitute a full-color pixel.

[0018] In a possible implementation of the first aspect, the micro light emitting diode display also includes: a third LED unit layer, bonded to the second LED unit layer, including a plurality of third LED units arranged at intervals, and the vertical projections of the first LED unit, the second LED unit and the third LED unit on the substrate do not overlap; wherein at least one first LED unit and at least one adjacent second LED unit and at least one adjacent third LED unit constitute a full-color pixel point.

[0019] According to a second aspect of the embodiment of the present application, a method for preparing a micro light emitting diode display is provided, comprising the following steps: providing a substrate; Prepare a first LED unit layer, the first LED unit layer comprising a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on a surface of the first LED unit layer away from the substrate side, and exposes a surface of the plurality of first LED units away from the substrate side; and the first passivation layer also at least covers side surfaces of the plurality of first LED units; bonding the first LED unit layer to the substrate; Prepare a second LED unit layer, wherein the second LED unit layer includes a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units; Bonding the second LED unit layer to the first LED unit layer, wherein the fill layer is bonded to the first passivation layer; Wherein, a plurality of the first LED units and a plurality of the second LED units are electrically connected to the substrate respectively to achieve separate driving.

[0020] In a possible implementation manner of the second aspect, the step of preparing the first LED unit layer includes: Providing a first substrate, on which a first LED epitaxial layer is disposed; Etching the first LED epitaxial layer (the side facing away from the first substrate) to form a plurality of first LED units; A first passivation layer is formed, wherein the first passivation layer covers the surface of the etched first LED epitaxial layer and exposes a portion of the surface of the plurality of first LED units away from the first substrate.

[0021] In a possible implementation manner of the second aspect, the step of preparing the first LED unit layer further includes: A first electrode layer is formed on a side of the first passivation layer away from the first LED unit, the first electrode layer is arranged around a side of the first LED unit and a side away from the first substrate, and the first electrode layer also covers a surface of the first LED unit away from the first substrate and not covered by the first passivation layer; forming a planarization layer, wherein the planarization layer covers the first passivation layer and the first electrode layer; A first conductive protrusion and a conductive column are formed, wherein one end of the first conductive protrusion is connected to the first electrode layer, and the other end vertically extends to the surface of the planarization layer away from the first substrate side; the conductive column vertically penetrates the planarization layer and the first passivation layer.

[0022] In a possible implementation manner of the second aspect, the step of bonding the first LED unit layer to the substrate includes: Bonding the planarization layer to the substrate, and bonding and electrically connecting the first conductive protrusions and the conductive pillars to the corresponding first contacts; The first substrate and a portion of the first LED epitaxial layer are removed until the surface of the first passivation layer is exposed, so that the first passivation layer, the first LED unit, and the surface of the conductive column facing away from the substrate are flush.

[0023] In a possible implementation manner of the second aspect, the step of preparing the second LED unit layer includes: Providing a second substrate, on which a second LED epitaxial layer is disposed; Etching the second LED epitaxial layer (the side facing away from the second substrate) to form a plurality of second LED units; forming a second passivation layer, wherein the second passivation layer covers the surface of the etched second LED epitaxial layer and exposes a portion of the surface of a plurality of second LED units away from the second substrate; A second electrode layer is formed on a side of the second passivation layer away from the second LED unit, the second electrode layer is arranged around a side of the second LED unit and a side away from the second substrate, and the second electrode layer covers a surface of the second LED unit away from the second substrate and not covered by the second passivation layer; forming a filling layer, wherein the filling layer covers the second passivation layer and the second electrode layer; A second conductive protrusion is formed on the leveling layer, one end of the second conductive protrusion is electrically connected to the second electrode layer, and the other end of the second conductive protrusion vertically extends to a surface of the leveling layer away from the second substrate.

[0024] In a possible implementation manner of the second aspect, the micro light emitting diode display further includes a conductive column, and the step of bonding the second LED unit layer to the first LED unit layer includes: Bonding the fill layer to the first passivation layer, and bonding and electrically connecting the second conductive protrusion to an end of the conductive column facing away from the substrate; The second substrate and a portion of the second LED epitaxial layer are removed until the surface of the second passivation layer is exposed, so that the second passivation layer is flush with the surface of the second LED unit facing away from the substrate.

[0025] In a possible implementation manner of the second aspect, after the step of bonding the second LED unit layer to the first LED unit layer, the preparation method further includes: Etching the second LED unit layer to expose the surface of the first LED unit facing away from the substrate; A common electrode layer is formed, the common electrode layer at least covers the surface of the first LED unit and the second LED unit away from the substrate, and the common electrode layer is electrically connected to the second contact of the substrate.

[0026] In a possible implementation manner of the second aspect, the preparation method further includes: forming a protective layer, wherein the protective layer at least covers the common electrode layer; A color conversion unit is formed on the protection layer, and the color conversion unit is located above a portion of the first LED unit or a portion of the second LED unit.

[0027] The micro light emitting diode display and the manufacturing method thereof provided in this application can at least achieve the following technical effects: By positioning the first passivation layer on the surface of the first LED unit layer away from the substrate and exposing the surfaces of the first LED units away from the substrate, the first passivation layer can be used as a processing position reference when processing the first LED unit layer, thereby reducing the difficulty and cost of the processing technology, and reducing the situation where the device is damaged due to excessive processing, so as to protect the first LED unit during the processing and improve the overall yield. By covering at least the sides of the first LED units with the first passivation layer, the first LED unit is protected, leakage is avoided or reduced, and the stability and reliability of the display are improved. By bonding the leveling layer to the first passivation layer, the first LED unit layer and the second LED unit layer are bonded and connected, further reducing the difficulty and cost of processing, improving the overall yield, and reducing the thickness of the display in the vertical direction, thereby reducing the size of the display.

[0028] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] One or more embodiments are exemplarily described by corresponding drawings, which do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements, and the drawings do not constitute a scale limitation, and wherein: Figure 1 A schematic structural diagram of a display provided for one embodiment of the present disclosure; Figure 2 Schematic structure of the structure in the process of preparing the first LED unit layer provided in the embodiment of the present disclosure Figure 1 ; Figure 3 Schematic structure of the structure in the process of preparing the first LED unit layer provided in the embodiment of the present disclosure Figure 2 ; Figure 4 Schematic structure of the structure in the process of preparing the first LED unit layer provided in the embodiment of the present disclosure Figure 3 ; Figure 5 Schematic structure of the structure in the process of preparing the first LED unit layer provided in the embodiment of the present disclosure Figure 4 ; Figure 6 Schematic structure of the structure in the process of preparing the first LED unit layer provided in the embodiment of the present disclosure Figure 5 ; Figure 7 Schematic structure of the structure in the process of preparing the first LED unit layer provided in the embodiment of the present disclosure Figure 6 ; Figure 8 Schematic structure of the structure in the process of preparing the first LED unit layer provided in the embodiment of the present disclosure Figure 7 ; Fig. 9 Schematic structure of the structure in the process of preparing the first LED unit layer provided in the embodiment of the present disclosure Figure 8 ; Fig.10 Schematic structure of the structure in the process of preparing the second LED unit layer provided in the embodiment of the present disclosure Figure 1 ; Fig.11 Schematic structure of the structure in the process of preparing the second LED unit layer provided in the embodiment of the present disclosure Figure 2 ; Fig.12 Schematic structure of the structure in the process of preparing the second LED unit layer provided in the embodiment of the present disclosure Figure 3 ; Fig.13 Schematic structure of the structure in the process of preparing the second LED unit layer provided in the embodiment of the present disclosure Figure 4 ; Fig.14 Schematic structure of the structure in the process of preparing the second LED unit layer provided in the embodiment of the present disclosure Figure 5 ; Fig.15 Schematic structure of the structure in the process of preparing the second LED unit layer provided in the embodiment of the present disclosure Figure 6 ; Fig.16 Schematic structure of the structure in the process of preparing the second LED unit layer provided in the embodiment of the present disclosure Figure 7 ; Fig.17 Schematic structure of the structure in the process of preparing the second LED unit layer provided in the embodiment of the present disclosure Figure 8 ; Fig.18 Schematic structure of the structure in the process of bonding the first LED unit layer to the substrate provided in the embodiment of the present disclosure Figure 1 ; Fig.19 Schematic structure of the structure in the process of bonding the first LED unit layer to the substrate provided in the embodiment of the present disclosure Figure 2 ; Fig. 20Schematic structure of the structure in the process of bonding the second LED unit layer to the first LED unit layer provided in the embodiment of the present disclosure Figure 1 ; Fig.21 Schematic structure of the structure in the process of bonding the second LED unit layer to the first LED unit layer provided in the embodiment of the present disclosure Figure 2 ; Fig. 22 For Fig.21 A schematic structural diagram of forming a common electrode layer on the structure provided in the illustrated embodiment; Fig.23 For Fig. 22 A schematic structural diagram of a protective layer formed on a structure provided by the illustrated embodiment; Fig.24 is a schematic structural diagram of etching a window in a protective layer; Fig.25 A schematic structural diagram of a display provided for another embodiment of the present disclosure; Fig.26 A flow chart of a method for preparing a display provided by one embodiment of the present disclosure; Fig. 27 A flow chart of a method for preparing a first LED unit layer provided in an embodiment of the present disclosure; Fig.28 A flow chart of a method for preparing a second LED unit layer provided in an embodiment of the present disclosure; Fig.29 A flow chart of a method for preparing a display provided in another embodiment of the present disclosure; Fig.30 A flowchart of a method for preparing a display provided in accordance with yet another embodiment of the present disclosure.

[0030] The reference numerals are as follows: 1: Display; 10: substrate; 11: first contact; 20: first LED unit layer; 21: first passivation layer; 22: first LED unit; 23: planarization layer; 24: first conductive protrusion; 25: first electrode layer; 26: conductive column; 261: first end; 262: second end; 27: first substrate; 28: first LED epitaxial layer; 30: second LED unit layer; 31: second LED unit; 32: filling layer; 33: second passivation layer; 34: second electrode layer; 35: second conductive protrusion; 36: second substrate; 37: second LED epitaxial layer; 40: common electrode layer; 41: protective layer; 42: color conversion unit; 50: third LED unit layer; 51: third LED unit; 52: third passivation layer; 53: filling layer; 54: third electrode; 55: conductive connecting column; 56: third conductive protrusion. DETAILED DESCRIPTION

[0031] In order to be able to understand the features and technical contents of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0032] The terms "first", "second", etc. in the specification and claims of the embodiments of the present disclosure 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 terms used in this way can be interchanged where appropriate, so that the embodiments of the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0033] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0034] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0035] Unless otherwise stated, the term "plurality" means two or more.

[0036] In the embodiment of the present disclosure, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B indicates: A or B.

[0037] The term "and / or" is a description of the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0038] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

[0039] It should be noted that the term "layer" used in the embodiments of the present disclosure refers to a material portion including an area with a certain thickness. The layer may extend over the entire lower or upper structure, or may have a degree less than the range of the lower or upper structure. In addition, a layer may be an area of ​​a homogeneous or inhomogeneous continuous structure, the thickness of which is less than the thickness of the continuous structure. For example, a layer may be located between the top surface and the bottom surface of the continuous structure or between any pair of horizontal planes therebetween. A layer may extend horizontally, vertically and / or along a tapered surface.

[0040] It should be noted that the term "micro" used in the embodiments of the present disclosure refers to the descriptive size of certain devices or structures according to the embodiments of the present application. The term "micro" device or structure used herein is intended to represent a scale of 0.1 to 100 μm. However, it should be understood that the embodiments of the present application are not necessarily limited thereto, and certain aspects of the embodiments may be applicable to larger and possibly smaller size scales.

[0041] In order to simplify the description, in the following explanation, part of the "micro light emitting diode display" is simply described as a "display".

[0042] According to the first aspect of the embodiment of the present application, Figures 1 to 25As shown, a micro light emitting diode display 1 is provided, comprising a substrate 10, a first LED unit layer 20 and a second LED unit layer 30. The first LED unit layer 20 is bonded to the substrate 10. The second LED unit layer 30 comprises a first passivation layer 21 and a plurality of first LED units 22 arranged at intervals. The first passivation layer 21 is located on the surface of the first LED unit layer 20 away from the substrate 10, and exposes the surface of the plurality of first LED units 22 away from the substrate 10. And the first passivation layer 21 also at least covers the side surfaces of the plurality of first LED units 22. The second LED unit layer 30 is bonded to the first LED unit layer 20. The second LED unit layer 30 comprises a plurality of second LED units 31 arranged at intervals and a filling layer 32 located between adjacent second LED units 31. The filling layer 32 is bonded to the first passivation layer 21. Among them, the plurality of first LED units 22 and the plurality of second LED units 31 are electrically connected to the substrate 10 respectively to achieve separate driving.

[0043] The first passivation layer 21 is located on the surface of the first LED unit layer 20 facing away from the substrate 10, and the first passivation layer 21 exposes the surfaces of the plurality of first LED units 22 facing away from the substrate 10, so that when preparing the micro light emitting diode display 1, the first passivation layer 21 can be used as a processing position reference, thereby reducing the difficulty and cost of the processing technology, and avoiding or reducing the situation where the device is damaged due to excessive processing, so as to protect the first LED units 22 during the processing and improve the overall yield.

[0044] Exemplarily, after the first LED unit layer 20 is bonded to the substrate 10, a portion of the first LED epitaxial layer 28 can be removed by chemical mechanical polishing (CMP). During the CMP process, the first passivation layer 21 is used as a processing position reference, that is, the CMP process is stopped when the first passivation layer 21 is exposed, which reduces the difficulty and cost of the processing technology. In addition, the first passivation layer 21 provides a clear reference position to avoid or reduce the situation where the device is damaged due to excessive processing, so as to effectively protect the first LED unit 22 during the processing process and improve the overall yield.

[0045] The first passivation layer 21 is located on the surface of the first LED unit layer 20 away from the substrate 10, so that the filling layer 32 is smoothly bonded to the first passivation layer 21. The first LED unit layer 20 and the second LED unit layer 30 are bonded by bonding the filling layer 32 to the first passivation layer 21, further reducing the processing difficulty and processing cost, and improving the overall yield. The thickness of the display 1 is reduced in the vertical direction, thereby reducing the size of the display 1.

[0046] The first passivation layer 21 at least covers the side surfaces of the plurality of first LED units 22. For example, the first passivation layer 21 can cover the side surfaces of the plurality of first LED units 22 and part of the surface of the plurality of first LED units 22 facing the substrate 10. The first passivation layer 21 at least covers the side surfaces of the plurality of first LED units 22, thereby protecting the first LED units 22. Furthermore, when the first LED units 22 are connected to electrodes, the first passivation layer 21 can also avoid or reduce leakage, thereby improving the stability and reliability of the display 1.

[0047] The micro light emitting diode display 1 includes a substrate 10, a first LED unit layer 20 and a second LED unit layer 30. The first LED unit layer 20 is bonded to the substrate 10, and the second LED unit layer 30 is bonded to the first LED unit layer 20, so that the thickness of the display 1 is reduced in the vertical direction, thereby reducing the size of the display 1. The processing technology is simple, the cost is low, and the economy is good.

[0048] By electrically connecting the plurality of first LED units 22 and the plurality of second LED units 31 to the substrate 10 respectively, each first LED unit 22 can be driven individually by the substrate 10 , and each second LED unit 31 can be driven individually by the substrate 10 .

[0049] It should be noted that the vertical direction can be understood as a direction that is vertical or nearly vertical to the upper surface of the substrate 10, that is, Figure 1 and Fig.25 In the direction from top to bottom.

[0050] In the present embodiment, substrate 10 refers to a material on which subsequent material layers are added. Substrate 10 itself may be patterned. The material added to the top of substrate 10 may be patterned or may remain unpatterned. In addition, substrate 10 may include a variety of semiconductor materials, such as silicon, silicon carbide, gallium nitride, germanium, gallium arsenide, indium phosphide. Alternatively, substrate 10 may be made of a non-conductive material, such as glass, plastic, or sapphire wafer. Further alternatively, substrate 10 may have a semiconductor device or circuit formed therein.

[0051] In addition, the substrate 10 may be provided with a circuit layer including complementary metal oxide semiconductor (CMOS) devices or thin film transistor (TFT) devices, etc. These CMOS devices or TFT devices may constitute a driving circuit.

[0052] In one possible implementation, combining Figure 1 and Fig.25As shown, along the vertical direction, the projections of the first LED unit 22 and the second LED unit 31 on the substrate 10 do not overlap. The first LED unit 22 is used to emit a first color light, and the second LED unit 31 is used to emit a second color light, and the first color light is different from the second color light.

[0053] By making the vertical projections of the first LED unit 22 and the second LED unit 31 on the substrate 10 non-overlapping, the brightness and color distribution of the displayed colors are made more uniform, thereby improving the user's visual experience.

[0054] The first color light is different from the second color light to achieve a colorful display. For example, the first color light is blue light and the second color light is green light. The first color light is blue light and the second color light is red light. For another example, the first color light is green light and the second color light is blue light. For another example, the first color light is green light and the second color light is red light. For another example, the first color light is red light and the second color light is green light. For another example, the first color light is red light and the second color light is blue light.

[0055] In a possible implementation, the material of the first passivation layer 21 includes aluminum oxide ( ) or silicon dioxide ( ).

[0056] In a possible implementation, the material of the leveling layer 32 includes silicon dioxide ( ), silicon nitride or benzocyclobutene (BCB).

[0057] It is understood that the shapes of the first LED unit 22 and the second LED unit 31 are not limited, for example, they may be in the shape of a truncated cone or a cube.

[0058] In some embodiments, in combination Figure 1 and Fig.25 As shown, the substrate 10 includes a plurality of first contacts 11. The first LED unit layer 20 also includes a planarization layer 23 and a first conductive protrusion 24. The planarization layer 23 is disposed on the side of the first passivation layer 21 facing the substrate 10, and the planarization layer 23 is bonded to the substrate 10. The first conductive protrusion 24 is disposed on the planarization layer 23. One end of the first conductive protrusion 24 is electrically connected to the first LED unit 22, and the other end is bonded and electrically connected to the corresponding first contact 11.

[0059] The planarization layer 23 is disposed on the side of the first passivation layer 21 facing the substrate 10, so that the planarization layer 23 can be smoothly bonded to the substrate 10, reducing the processing difficulty and cost. It can also reduce the overall thickness of the display 1 in the vertical direction, thereby reducing the size of the display 1.

[0060] The first conductive protrusion 24 is disposed on the planarization layer 23, specifically, the first conductive protrusion 24 is disposed on the side of the first LED unit layer 20 facing the substrate 10. One end of the first conductive protrusion 24 is smoothly electrically connected to the first LED unit 22, and the other end of the first conductive protrusion 24 is smoothly bonded and electrically connected to the corresponding first contact 11. In turn, the first contact 11 of the substrate 10 can apply a voltage to the first LED unit 22 alone, so that the first LED unit 22 is driven alone.

[0061] It should be noted that the bonding of the first conductive protrusion 24 to the corresponding first contact 11 means that each first contact 11 is electrically connected to only one first LED unit 22 or second LED unit layer 30. Therefore, each first conductive protrusion 24 is used to connect a first LED unit 22 and the corresponding first contact 11.

[0062] In a possible implementation, the material of the planarization layer 23 includes silicon dioxide ( ), silicon nitride or benzocyclobutene (BCB).

[0063] In a possible implementation, the material of the first conductive protrusion 24 includes copper (Cu).

[0064] In one possible implementation, combining Figure 1 and Figures 18 to 25 As shown, the surface area of ​​the first conductive protrusion 24 bonding to the first contact 11 is larger than the surface area of ​​the first conductive protrusion 24 connecting to the first LED unit 22 .

[0065] Combination Figure 1 , Fig.18 and Fig.19 As shown, A is used to indicate the bonding side of the first conductive protrusion 24 and the first contact 11, and B is used to indicate the connection side of the first conductive protrusion 24 and the first LED unit 22. By making the surface area of ​​the lower end of the first conductive protrusion 24 larger than the surface area of ​​the upper end, the size of the display 1 can be reduced to a certain extent, and the bonding accuracy of the first conductive protrusion 24 and the first contact 11 can be improved, so that more first LED units 22 can be integrated on the same display area, the pixel density can be increased, and the resolution and display effect of the device can be improved.

[0066] In a possible implementation, the display 1 further includes a first connection layer, which is disposed between the first LED unit layer 20 and the substrate 10. The first connection layer has a plurality of solder pads arranged at intervals. In the vertical direction, the solder pad runs through the first connection layer. One side of the first connection layer is bonded to the substrate 10, and the other side is bonded to the planarization layer 23 of the first LED unit layer 20. One end of the solder pad is bonded and electrically connected to the first contact 11 of the substrate 10, and the other end of the solder pad is bonded and electrically connected to the first conductive protrusion 24, so as to achieve bonding of the first LED unit layer 20 to the substrate 10.

[0067] It should be noted that the material of the first connection layer is not limited, for example, silicon dioxide. The material of the solder pad is not limited, for example, copper.

[0068] In some embodiments, in combination Figure 1 , Figures 5 to 9 as well as Figures 18 to 25 As shown, the first LED unit layer 20 further includes a first electrode layer 25. The first electrode layer 25 is disposed on a side of the first passivation layer 21 away from the first LED unit 22, and is disposed around the side of the first LED unit 22 and the side facing the substrate 10. In addition, the first electrode layer 25 covers the surface of the first LED unit 22 facing the substrate 10 and not covered by the first passivation layer 21. The first electrode layer 25 reflects the light emitted by the first LED unit 22.

[0069] The first electrode layer 25 is disposed around the side of the first LED unit 22 and the side facing the substrate 10. Figure 1 As shown, the first electrode layer 25 is arranged around the side and bottom of the first LED unit 22 to form a reflective cup on the side and bottom of the first LED unit 22, so that the first electrode layer 25 can reflect the light emitted by the first LED unit 22, improve the light extraction efficiency, and prevent or reduce optical crosstalk. The reflective cup can also reduce the light hitting the adjacent first LED unit 22, further improving the light extraction efficiency. In addition, the reflective cup can make the light spot more concentrated and the pixel points more compact. While reducing the size of the display 1, more first LED units 22 can be integrated on the same display area, thereby improving the pixel density, and improving the resolution and display effect of the device.

[0070] The first electrode layer 25 covers the surface of the first LED unit 22 facing the substrate 10 and not covered by the first passivation layer 21, so that the first electrode layer 25 is electrically connected to the first LED unit 22. Figure 1 As shown, the first electrode layer 25 is electrically connected to the bottom of the first LED unit 22 .

[0071] The first electrode layer 25 is disposed on the side of the first passivation layer 21 away from the first LED unit 22, that is, in the side and bottom surfaces of the first LED unit 22, except for the position where the first electrode layer 25 is electrically connected to the first LED unit 22, the first passivation layer 21 is disposed between the first electrode layer 25 and the first LED unit 22 at other positions. The first passivation layer 21 protects the first LED unit 22, prevents or reduces leakage, and improves the stability and reliability of the display 1.

[0072] It should be noted that the material of the first electrode layer 25 is not limited, for example, it can be aluminum or silver.

[0073] In one possible implementation, combining Figure 1 as well as Figures 18 to 25 As shown, the side of the first electrode layer 25 facing away from the first LED unit 22 is electrically connected to the end of the first conductive protrusion 24 facing away from the first contact 11, that is, the first contact 11 is electrically connected to the first LED unit 22 through the first conductive protrusion 24 and the first electrode layer 25 to apply voltage to the first LED unit 22 alone.

[0074] In some embodiments, in combination Figure 1 , Figures 12 to 17 as well as Figure 20 to Figure 25 As shown, the second LED unit layer 30 further includes a second passivation layer 33. The second passivation layer 33 is disposed on the surface of the fill layer 32 away from the substrate 10, and exposes the surfaces of the plurality of second LED units 31 away from the substrate 10. The second passivation layer 33 also at least covers the side surfaces of the plurality of second LED units 31.

[0075] By setting the second passivation layer 33 on the surface of the filling layer 32 facing away from the substrate 10 and exposing the surfaces of the plurality of second LED units 31 facing away from the substrate 10, the second passivation layer 33 can be used as a processing position reference when preparing the micro light emitting diode display 1, thereby reducing the difficulty and cost of the processing technology and avoiding or reducing the situation where the device is damaged due to excessive processing, so as to protect the second LED units 31 during the processing and improve the overall yield.

[0076] In a specific example, when preparing the micro-LED display 1, the first LED unit layer 20 is first bonded to the substrate 10, and then the second LED unit layer 30 is bonded to the first LED unit layer 20. After the second LED unit layer 30 is bonded to the first LED unit layer 20, part of the first LED epitaxial layer 28 can be removed by chemical mechanical polishing (CMP). The CMP process is stopped when the first passivation layer 21 is exposed, so as to avoid or reduce over-processing, effectively protect the first LED unit 22, and reduce the difficulty and cost of the processing technology. This provides a connection surface for bonding the second LED unit layer 30 to the first LED unit layer 20, and enables the first LED unit 22 to emit light effectively. After the second LED unit layer 30 is bonded to the first LED unit layer 20, part of the second LED epitaxial layer 37 can be removed by CMP processing. The CMP process is stopped when the second passivation layer 33 is exposed, so as to avoid or reduce over-processing, effectively protect the second LED unit 31, and reduce the difficulty and cost of the processing technology. The first passivation layer 21 and the second passivation layer 33 cooperate to serve as processing position references for different processing steps, thereby reducing the overall processing difficulty and improving the yield.

[0077] In another specific example, when the display 1 further includes the third LED unit layer 50, the second passivation layer 33 is disposed on the surface of the leveling layer 32 facing away from the substrate 10, so that the second passivation layer 33 and the third LED unit layer 50 can be smoothly bonded, reducing the processing difficulty and processing cost, and improving the overall yield. The thickness of the display 1 is reduced in the vertical direction, thereby reducing the size of the display 1.

[0078] The second passivation layer 33 at least covers the side surfaces of the plurality of second LED units 31. For example, the second passivation layer 33 may cover the side surfaces of the plurality of second LED units 31 and a portion of the surface of the plurality of second LED units 31 facing the substrate 10. The second passivation layer 33 at least covers the side surfaces of the plurality of second LED units 31, thereby protecting the second LED units 31. Furthermore, when the second LED units 31 are connected to electrodes, the second passivation layer 33 may also avoid or reduce leakage, thereby improving the stability and reliability of the display 1.

[0079] In a possible implementation, the material of the second passivation layer 33 includes aluminum oxide ( ) or silicon dioxide ( ).

[0080] In some embodiments, in combination Figure 1 , Figures 13 to 17 as well as Figure 20 to Figure 25As shown, the second LED unit layer 30 further includes a second electrode layer 34. The second electrode layer 34 is disposed on the side of the second passivation layer 33 away from the second LED unit 31, and is disposed around the side of the second LED unit 31 and the side facing the substrate 10. In addition, the second electrode layer 34 covers the surface of the second LED unit 31 facing the substrate 10 and not covered by the second passivation layer 33. The second electrode layer 34 reflects the light emitted by the second LED unit 31.

[0081] The second electrode layer 34 is disposed around the side of the second LED unit 31 and the side facing the substrate 10. Figure 1 As shown, the second electrode layer 34 is arranged around the side and bottom of the second LED unit 31 to form a reflective cup on the side and bottom of the second LED unit 31, so that the second electrode layer 34 can reflect the light emitted by the second LED unit 31, improve the light extraction efficiency, and prevent or reduce optical crosstalk. The reflective cup can also reduce the light hitting the adjacent second LED unit 31, further improving the light extraction efficiency. In addition, the reflective cup can make the light spot more concentrated and the pixel points more compact. While reducing the size of the display 1, more second LED units 31 can be integrated on the same display area, thereby improving the pixel density, and improving the resolution and display effect of the device.

[0082] The second electrode layer 34 covers the surface of the second LED unit 31 facing the substrate 10 and not covered by the second passivation layer 33, so that the second electrode layer 34 is electrically connected to the second LED unit 31. Figure 1 As shown, the second electrode layer 34 is electrically connected to the bottom of the second LED unit 31 .

[0083] The second electrode layer 34 is disposed on the side of the second passivation layer 33 away from the second LED unit 31, that is, in the side and bottom surfaces of the first LED unit 22, except for the position where the second electrode layer 34 is electrically connected to the second LED unit 31, the second passivation layer 33 is disposed between the second electrode layer 34 and the second LED unit 31 at other positions. The second passivation layer 33 protects the second LED unit 31, prevents or reduces leakage, and improves the stability and reliability of the display 1.

[0084] It should be noted that the material of the second electrode layer 34 is not limited, for example, it can be aluminum or silver.

[0085] In some embodiments, in combination Figure 1 , Fig. 9 , Figures 18 to 25As shown, the micro light emitting diode display 1 also includes a conductive column 26. The conductive column 26 vertically penetrates the first LED unit layer 20. One end of the conductive column 26 is electrically connected to the substrate 10, and the other end of the conductive column 26 is electrically connected to the corresponding second LED unit 30. Specifically, the conductive column 26 includes a first end 261 and a second end 262, and the first end 261 of the conductive column 26 is bonded to the first contact 11 of the corresponding substrate 10. The second LED unit layer 30 also includes a second conductive protrusion 35 provided on the filling layer 32. The second conductive protrusion 35 is electrically connected to the second LED unit 30. Among them, the conductive column 26 is electrically connected to the second LED unit 30 through the second conductive protrusion 35. Specifically, one end of the second conductive protrusion 35 is electrically connected to the second electrode layer 34, and the other end of the second conductive protrusion 35 is bonded and electrically connected to the second end 262 of the conductive column 26.

[0086] The conductive column 26 vertically penetrates the first LED unit layer 20, and is combined with Figure 1 As shown, the conductive column 26 penetrates the first LED unit layer 20 from top to bottom, so that the first end 261 of the conductive column 26 is smoothly bonded and electrically connected to the first contact 11 directly below it, and the second end 262 of the conductive column 26 is smoothly bonded and electrically connected to the second conductive protrusion 35 directly above it. In addition, the end of the second conductive protrusion 35 away from the conductive column 26 is electrically connected to the second electrode layer 34, and the second electrode layer 34 is electrically connected to the second LED unit 31, so that the first contact 11 of the substrate 10 can apply a voltage to the second LED unit 31 alone, so that the second LED unit 31 is driven alone.

[0087] The second conductive protrusion 35 is disposed on the filling layer 32, specifically, the second conductive protrusion 35 is disposed on the side of the second LED unit layer 30 facing the substrate 10. One end of the second conductive protrusion 35 is smoothly electrically connected to the second electrode layer 34, and the other end of the second conductive protrusion 35 is smoothly bonded and electrically connected to the second end 262 of the conductive column 26, thereby reducing the difficulty of processing.

[0088] It should be noted that the bonding of the first end 261 of the conductive column 26 with the corresponding first contact 11 means that each first contact 11 is electrically connected to only one first LED unit 22 or second LED unit layer 30. Therefore, each conductive column 26 and each second conductive protrusion 35 are used to connect a second LED unit 31 and the corresponding first contact 11.

[0089] In a possible implementation, the material of the second conductive protrusion 35 includes copper (Cu).

[0090] In a possible implementation, the micro-light emitting diode display 1 further includes a second connection layer, which is disposed between the first LED unit layer 20 and the second LED unit layer 30. The second connection layer has a plurality of pads arranged at intervals. In the vertical direction, the pads penetrate the second connection layer. One side of the second connection layer is bonded to the first passivation layer 21, and the other side is bonded to the filling layer 32 of the second LED unit layer 30. One end of the pad is bonded to and electrically connected to the second end 262 of the conductive column 26, and the other end of the pad is bonded to and electrically connected to the second conductive protrusion 35, so as to achieve bonding of the second LED unit layer 30 to the first LED unit layer 20.

[0091] It should be noted that the material of the second connection layer is not limited, for example, silicon dioxide. The material of the solder pad is not limited, for example, copper.

[0092] In some embodiments, in combination Figure 1 and Fig.21 As shown, the surface area of ​​the second conductive protrusion 35 bonding to the conductive pillar 26 is larger than the surface area of ​​the second conductive protrusion 35 connecting to the second electrode layer 34 .

[0093] Fig.21 In the figure, C is used to indicate the bonding side of the second conductive protrusion 35 and the conductive column 26, and D is used to indicate the connection side of the second conductive protrusion 35 and the second electrode layer 34. By making the surface area of ​​the lower end of the second conductive protrusion 35 larger than the surface area of ​​the upper end, the size of the display 1 can be reduced to a certain extent, and the bonding accuracy of the second conductive protrusion 35 and the conductive column 26 can be improved, so that more second LED units 31 can be integrated on the same display area, the pixel density can be improved, and then the resolution and display effect of the device can be improved.

[0094] In some embodiments, the first LED unit 22 and the second LED unit 31 respectively include a first doped semiconductor layer, an active layer, and a second doped semiconductor layer that are stacked. The first doped semiconductor layer is close to the substrate 10. The surface of the second doped semiconductor layer of the first LED unit 22 facing away from the substrate 10 is flush with the surface of the first passivation layer 21 facing away from the substrate 10. The surface of the second doped semiconductor layer of the second LED unit 31 facing away from the substrate 10 is flush with the surface of the second passivation layer 33 facing away from the substrate 10.

[0095] Specifically, the first LED unit 22 includes a first doped semiconductor layer, an active layer, and a second doped semiconductor layer that are stacked. The second LED unit 31 includes a first doped semiconductor layer, an active layer, and a second doped semiconductor layer that are stacked. The first doped semiconductor layer is close to the substrate 10, that is, the second doped semiconductor layer is away from the substrate 10, so that the first doped semiconductor layer is smoothly electrically connected to the substrate 10, and the second doped semiconductor layer can be effectively protected by the first passivation layer 21 or the second passivation layer 33, thereby improving the yield.

[0096] By making the surface of the second doped semiconductor layer of the first LED unit 22 facing away from the substrate 10 flush with the surface of the first passivation layer 21 facing away from the substrate 10, when preparing the micro light emitting diode display 1, the first passivation layer 21 can be used as a processing position reference to protect the second doped semiconductor layer, avoid or reduce the situation where the second doped semiconductor layer is damaged due to excessive processing, reduce the processing difficulty, and improve the overall yield.

[0097] By making the surface of the second doped semiconductor layer of the second LED unit 31 facing away from the substrate 10 flush with the surface of the second passivation layer 33 facing away from the substrate 10, when preparing the micro light emitting diode display 1, the second passivation layer 33 can be used as a processing position reference to protect the second doped semiconductor layer, avoid or reduce the situation where the second doped semiconductor layer is damaged due to excessive processing, reduce the processing difficulty, and improve the overall yield.

[0098] The first doped semiconductor layer may be a p-type semiconductor layer, for example, specifically, p-type gallium nitride (GaN) or p-type aluminum indium gallium nitride (AlInGaN). Correspondingly, the second doped semiconductor layer may be an n-type semiconductor layer, for example, specifically, n-type gallium nitride (GaN) or n-type aluminum indium gallium nitride (AlInGaN).

[0099] In some embodiments, the substrate 10 includes at least one second contact (not shown). The micro-LED display 1 also includes a common electrode layer 40, which is electrically connected to the surfaces of the first LED unit 22 and the second LED unit 31 facing away from the substrate 10, and the common electrode layer 40 is electrically connected to the second contact.

[0100] Specifically, the common electrode layer 40 may cover the surface of the first LED unit 22 facing away from the substrate 10, and be electrically connected to the first LED unit 22. At the same time, the common electrode layer 40 also covers the surface of the second LED unit 31 facing away from the substrate 10, and is electrically connected to the second LED unit 31. By electrically connecting the same common electrode layer 40 to the surfaces of the first LED unit 22 and the second LED unit 31 facing away from the substrate 10, the thickness of the display 1 is reduced in the vertical direction, and the overall size of the display 1 is reduced.

[0101] The common electrode layer 40 is electrically connected to the second contact, and each first LED unit 22 and each second LED unit 31 are electrically connected to the corresponding first contact 11 individually, so that each first LED unit 22 and each second LED unit 31 are driven individually.

[0102] In a specific example, the first contact 11 is an anode metal contact, and the second contact is a cathode metal contact. The first doped semiconductor layer is a p-type semiconductor layer, and the second doped semiconductor layer is an n-type semiconductor layer. A first contact 11 is electrically connected to a first doped semiconductor layer of a first LED unit 22 through a first conductive protrusion 24 and a first electrode layer 25. The second doped semiconductor layers of a plurality of first LED units 22 are electrically connected to the second contact through a common electrode layer 40 (forming a common cathode structure) to drive the active layer of the first LED unit 22 to emit light, for example, to emit green light, blue light or red light.

[0103] In another specific example, the first contact 11 is an anode metal contact, and the second contact is a cathode metal contact. The first doped semiconductor layer is a p-type semiconductor layer, and the second doped semiconductor layer is an n-type semiconductor layer. A first contact 11 is electrically connected to a first doped semiconductor layer of a second LED unit 31 through a conductive column 26, a second conductive protrusion 35, and a second electrode layer 34. The second doped semiconductor layers of a plurality of second LED units 31 are electrically connected to the second contact through a common electrode layer 40 (forming a common cathode structure) to drive the active layer of the second LED unit 31 to emit light, for example, to emit green light, blue light, or red light.

[0104] It should be noted that the common electrode layer 40 is specifically a transparent common electrode layer 40, so that the light of the first LED unit 22 and the second LED unit 31 can be smoothly emitted. The material of the common electrode layer 40 is not limited, for example, it can be indium tin oxide (ITO).

[0105] In some embodiments, in combination Figure 1 As shown, the display 1 also includes a plurality of color conversion units 42. The plurality of color conversion units 42 are arranged at intervals on the side of the second LED unit layer 30 away from the substrate 10, and are located on part of the first LED unit 22 or part of the second LED unit 31. The color conversion unit 42 is used to convert the first color light emitted by the first LED unit 22 or the second color light emitted by the second LED unit 31 into a third color light. The first color light, the second color light and the third color light are different. Among them, at least one first LED unit 22 and at least one adjacent second LED unit 31 and at least one adjacent color conversion unit 42 constitute a full-color pixel.

[0106] The plurality of color conversion units 42 are arranged at intervals on the side of the second LED unit layer 30 away from the substrate 10, and are located above part of the first LED units 22 or part of the second LED units 31. Specifically, some of the first LED units 22 among the plurality of first LED units 22 are provided with color conversion units 42, and / or, some of the second LED units 31 among the plurality of second LED units 31 are provided with color conversion units 42. Of course, the vertical projection of the color conversion unit 42 and the first LED unit 22 below on the substrate 10 may partially or completely overlap, and the vertical projection of the color conversion unit 42 and the second LED unit 31 below on the substrate 10 may partially or completely overlap.

[0107] When the color conversion unit 42 is located above the first LED unit 22, the color conversion unit 42 is used to convert the first color light emitted by the first LED unit 22 into a third color light. For example, the color conversion unit 42 converts the green light emitted by the first LED unit 22 into red light.

[0108] When the color conversion unit 42 is located above the second LED unit 31, the color conversion unit 42 is used to convert the second color light emitted by the second LED unit 31 into a third color light. For example, the color conversion unit 42 converts the blue light emitted by the second LED unit 31 into red light.

[0109] At least one first LED unit 22, at least one adjacent second LED unit 31, and at least one adjacent color conversion unit 42 form a full-color pixel. That is, full-color display is achieved by the first color light emitted by the first LED unit 22, the second color light emitted by the at least one adjacent second LED unit 31, and the third color light converted by the at least one adjacent color conversion unit 42. The first LED unit layer 20 is hybrid-bonded to the substrate 10, the second LED unit layer 30 is hybrid-bonded to the first LED unit layer 20, and the color conversion unit 42 performs color conversion, that is, through two hybrid bondings and one color conversion, the luminous efficiency is improved and the processing difficulty is reduced.

[0110] For example, Figure 1 As shown, among the three adjacent sub-pixels, one is provided with a first LED unit 22 for emitting green light. One is provided with a second LED unit 31 for emitting blue light. One is provided with a second LED unit 31, and a color conversion unit 42 is provided on the second LED unit 31. The color conversion unit 42 is used to convert the blue light emitted by the second LED unit 31 into red light for emission, so as to achieve full-color display, improve luminous efficiency, simplify the manufacturing process, and reduce the processing difficulty and processing cost.

[0111] In a possible implementation, the material of the color conversion unit 42 includes quantum dot photoresist (QDPR).

[0112] In one possible implementation, combining Figure 1 and Fig.25 As shown, the micro light emitting diode display 1 further includes a protective layer 41 . The protective layer 41 is disposed on the common electrode layer 40 , and at least covers the common electrode layer 40 . The color conversion unit 42 is disposed on the protective layer 41 .

[0113] The protective layer 41 can improve the integrity and stability of the display 1 and increase the light extraction rate.

[0114] It should be noted that the protective layer 41 is specifically a transparent protective layer 41 , which protects the device while allowing the display 1 to emit light effectively.

[0115] In a possible implementation, the material of the protection layer 41 includes polyimide, benzocyclobutene (BCB) or filling glue.

[0116] In some embodiments, in combination Fig.25 As shown, the display 1 also includes a third LED unit layer 50. The third LED unit layer 50 is bonded to the second LED unit layer 30. The third LED unit layer 50 includes a plurality of third LED units 51 arranged at intervals. The vertical projections of the first LED unit 22, the second LED unit 31, and the third LED unit 51 on the substrate 10 do not overlap. Among them, at least one first LED unit 22, at least one adjacent second LED unit 31, and at least one adjacent third LED unit 51 constitute a full-color pixel.

[0117] The vertical projections of the first LED unit 22, the second LED unit 31 and the third LED unit 51 on the substrate 10 do not overlap, so that the first LED unit 22, the second LED unit 31 and the third LED unit 51 can emit light independently, improve the light-emitting efficiency and reduce crosstalk. Among them, the first LED unit 22 emits a first color light, the second LED unit 31 emits a second color light, and the third LED unit 51 emits a third color light. The first color light, the second color light and the third color light are different, so as to achieve full-color display and improve the color response speed and long-term stability. For example, the first color light is green light, the second color light is blue light, and the third color light is red light. For another example, the first color light is green light, the second color light is red light, and the third color light is blue light. For another example, the first color light is blue light, the second color light is green light, and the third color light is red light. For another example, the first color light is blue light, the second color light is red light, and the third color light is green light. For another example, the first color light is red light, the second color light is green light, and the third color light is blue light. For another example, the first color light is red light, the second color light is blue light, and the third color light is green light.

[0118] A full-color pixel is formed by at least one first LED unit 22, at least one adjacent second LED unit 31, and at least one adjacent third LED unit 51. That is, the first LED unit 22 emits the first color light, the at least one adjacent second LED unit 31 emits the second color light, and the at least one adjacent third LED unit 51 emits the third color light, so that full-color display is achieved.

[0119] In one possible implementation, combining Fig.25 As shown, the third LED unit layer 50 further includes a filling layer 53 located between adjacent third LED units 51 , and the filling layer 53 is bonded to the second passivation layer 33 to achieve bonding of the third LED unit layer 50 to the second LED unit layer 30 .

[0120] In one possible implementation, combining Fig.25 As shown, the third LED unit layer 50 further includes a third passivation layer 52, which is disposed on the surface of the filling layer 53 away from the substrate 10 and exposes the surfaces of the third LED units 51 away from the substrate 10. The third passivation layer 52 at least covers the side surfaces of the third LED units 51.

[0121] When preparing the display 1, the third passivation layer 52 is used as a processing position reference to reduce the difficulty and cost of the processing technology, and avoid or reduce the situation where the device is damaged due to excessive processing, so as to protect the third LED unit 51 during the processing and improve the overall yield.

[0122] The third passivation layer 52 at least covers the side surfaces of the plurality of third LED units 51. For example, the third passivation layer 52 may cover the side surfaces of the plurality of third LED units 51 and a portion of the surface of the plurality of third LED units 51 facing the substrate 10. The third LED units 51 are protected and when the third LED units 51 are connected to electrodes, the third passivation layer 52 can also avoid or reduce leakage, thereby improving the stability and reliability of the display 1.

[0123] In a possible implementation, the material of the third passivation layer 52 includes aluminum oxide ( ) or silicon dioxide ( ).

[0124] In one possible implementation, combining Fig.25As shown, the third LED unit layer 50 further includes a third electrode 54. The third electrode 54 is disposed on the side of the third passivation layer 52 away from the third LED unit 51, and is disposed around the side of the third LED unit 51 and the side facing the substrate 10. In addition, the third electrode 54 covers the surface of the third LED unit 51 facing the substrate 10 and not covered by the third passivation layer 52. The third electrode 54 reflects the light emitted by the third LED unit 51. The technical effect of the third electrode 54 refers to the technical effects of the second electrode layer 34 and the first electrode layer 25 in the aforementioned embodiment, and will not be repeated here.

[0125] In one possible implementation, combining Fig.25 As shown, the display 1 further includes a conductive connection column 55. The conductive column 26 vertically penetrates the second LED unit layer 30. The third LED unit layer 50 further includes a third conductive protrusion 56. One end of the conductive connection column 55 is bonded and electrically connected to the conductive column 26, and the other end of the conductive connection column 55 is bonded and electrically connected to the third conductive protrusion 56. One end of the third conductive protrusion 56 facing away from the conductive connection column 55 is bonded and electrically connected to the third electrode 54, so that the third LED unit layer 50 can be driven independently by the substrate 10.

[0126] In one possible implementation, combining Fig.25 As shown, the common electrode layer 40 is also electrically connected to the surface of the third LED unit 51 facing away from the substrate 10 .

[0127] Combination Fig.26 As shown, according to the second aspect of the embodiment of the present application, a method for preparing a micro light emitting diode display 1 is provided, which is used to prepare the display 1. The preparation method comprises the following steps: S261. Provide a substrate.

[0128] like Figure 1 as well as Figures 18 to 25 As shown, the first LED unit 22 and the plurality of second LED units 31 are driven individually through the substrate 10 .

[0129] S262. Prepare a first LED unit layer, the first LED unit layer comprising a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on a surface of the first LED unit layer facing away from the substrate side, and exposes the surface of the plurality of first LED units facing away from the substrate side; and the first passivation layer also at least covers the side surfaces of the plurality of first LED units.

[0130] Combination Figures 1 to 9As shown, by preparing the first LED unit layer 20, preparation is made for bonding the first LED unit layer 20 as a whole to the substrate 10, thereby improving the yield of each structure in the first LED unit layer 20 during processing. The first passivation layer 21, the first LED unit 22 and the technical effects of the arrangement refer to the above-mentioned embodiment, which will not be repeated here.

[0131] S263, bonding the first LED unit layer to the substrate.

[0132] Combination Fig.18 and Fig.19 As shown, by bonding the entire first LED unit layer 20 to the substrate 10 , the processing technology is simplified, the processing difficulty is reduced, and the yield is improved.

[0133] S264, preparing a second LED unit layer, the second LED unit layer comprising a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units.

[0134] Combination Figure 1 as well as Figures 10 to 17 As shown, by preparing the second LED unit layer 30, preparation is made for bonding the entire second LED unit layer 30 to the first LED unit layer 20, thereby improving the yield of each structure in the second LED unit layer 30 during processing. The filling layer 32, the first LED unit 22 and the technical effects of the arrangement refer to the above-mentioned embodiment and will not be repeated here.

[0135] S265, bonding the second LED unit layer to the first LED unit layer, wherein the leveling layer is bonded to the first passivation layer.

[0136] The plurality of first LED units 22 and the plurality of second LED units 31 are electrically connected to the substrate 10 respectively to achieve separate driving.

[0137] Combination Figure 20 to Figure 21 As shown, by bonding the entire second LED unit layer 30 to the first LED unit layer 20, the processing technology is simplified, the processing difficulty is reduced, and the yield is improved.

[0138] In some embodiments, in combination Figures 2 to 4 As shown, the steps of preparing the first LED unit layer 20 include: providing a first substrate 27, on which a first LED epitaxial layer 28 is disposed. Etching a side of the first LED epitaxial layer 28 away from the first substrate 27 to form a plurality of first LED units 22. Forming a first passivation layer 21, the first passivation layer 21 covers a surface of the first LED epitaxial layer 28 away from the first substrate 27 and surfaces of the plurality of first LED units 22, and exposes a portion of the surface of the plurality of first LED units 22 away from the first substrate 27.

[0139] Combination Figure 2 As shown, the first substrate 27 provides support to make the structure of the entire first LED unit layer 20 more stable. For example, the first LED epitaxial layer 28 can be grown on the first substrate 27, and the first substrate 27 provides stable support for the growth of the first LED epitaxial layer 28.

[0140] It should be noted that the material of the first substrate 27 is not limited, for example, it can be silicon, sapphire or gallium nitride. The material of the first LED epitaxial layer 28 is not limited, for example, it can be gallium nitride (GaN).

[0141] Combination Figure 3 As shown, by etching the side of the first LED epitaxial layer 28 away from the first substrate 27, a plurality of mesa structures (MESA) are formed on the first LED epitaxial layer 28, each of which is a complete first LED unit 22, that is, the first LED unit 22 can be independently driven and emit light by the substrate 10. Specifically, the plurality of first LED units 22 are arranged at intervals.

[0142] like Figure 4 As shown, a first passivation layer 21 can be formed on a surface of the first LED epitaxial layer 28 facing away from the first substrate 27 by depositing a material (e.g., aluminum oxide or silicon dioxide), so that the first passivation layer 21 covers the surface of the first LED epitaxial layer 28 facing away from the first substrate 27 and the surfaces of the plurality of first LED units 22. The first passivation layer 21 is etched to form a plurality of windows. Figure 4 G1 is used to indicate the window formed by etching the first passivation layer 21. The multiple windows expose the partial surface of the multiple first LED units 22 facing away from the first substrate 27 in a one-to-one correspondence, and prepare the structure for the subsequent electrical connection between the first LED units 22 and the first electrode layer 25.

[0143] In some embodiments, Figures 5 to 9 As shown, the step of preparing the first LED unit layer 20 also includes: forming a first electrode layer 25 on the side of the first passivation layer 21 away from the first LED unit 22, the first electrode layer 25 is arranged around the side of the first LED unit 22 and the side away from the first substrate 27, and the first electrode layer 25 covers the surface of the first LED unit 22 away from the first substrate 27 and not covered by the first passivation layer 21. Forming a planarization layer 23, the planarization layer 23 covers the first passivation layer 21 and the first electrode layer 25. Forming a first conductive protrusion 24 and a conductive column 26, one end of the first conductive protrusion 24 is connected to the first electrode layer 25, and the other end extends vertically to the surface of the planarization layer 23 away from the first substrate 27; the conductive column 26 vertically penetrates the planarization layer 23 and the first passivation layer 21.

[0144] Specifically, if Figure 5As shown, a material can be deposited on the side of the first passivation layer 21 away from the first substrate 27 to form a metal layer. The metal layer can cover the surface of the first LED unit 22 away from the first substrate 27 and the area not covered by the first passivation layer 21. The metal layer is processed by a photolithography patterning process to form a first electrode layer 25, so that the first electrode layer 25 is arranged around the side of the first LED unit 22 and the side of the first LED unit 22 away from the first substrate 27.

[0145] like Figure 6 As shown, after forming the first electrode layer 25, a material (such as silicon dioxide) is deposited on the surface of the first passivation layer 21 away from the first substrate 27 to form a planarization layer 23, so that the planarization layer 23 covers the first passivation layer 21 and the first electrode layer 25. Figure 7 As shown, the planarization layer 23 corresponding to the first electrode layer 25 is etched, and the planarization layer 23 and the first passivation layer 21 corresponding to the conductive pillars 26 are etched to form a plurality of through holes ( Figure 7 G2 in the figure is used to illustrate a through hole), and structural preparation is performed to form a first conductive protrusion 24 and a conductive column 26. Figure 8 As shown, in the case of multiple through-holes filled with materials (eg, copper), the filling material method is not limited, for example, it can be filled by deposition and electroplating (Cu Seed Deposition and Plating). Fig. 9 As shown, after the filling material, part of the planarization layer 23 and part of the filling material are removed by chemical mechanical polishing (CMP) to obtain a first conductive protrusion 24, a conductive column 26 and the planarization layer 23 after CMP processing, and one end of the first conductive protrusion 24 is connected to the first electrode layer 25, and the other end of the first conductive protrusion 24 vertically extends to the surface of the planarization layer 23 after CMP processing away from the first substrate 27 side, and the conductive column 26 vertically penetrates the first passivation layer 21 and the planarization layer 23 after CMP processing.

[0146] Combination Figures 2 to 9 as well as Fig. 27 As shown, in a possible implementation, a method for preparing a first LED unit layer 20 is provided, comprising: S271. Provide a first substrate, on which a first LED epitaxial layer is disposed.

[0147] S272, etching the first LED epitaxial layer to form a plurality of first LED units.

[0148] S273, forming a first passivation layer, wherein the first passivation layer covers the surface of the etched first LED epitaxial layer and exposes a portion of the surface of the plurality of first LED units away from the first substrate.

[0149] S274. Form a first electrode layer on a side of the first passivation layer away from the first LED unit. The first electrode layer surrounds the side of the first LED unit and the side away from the first substrate. The first electrode layer also covers the surface of the first LED unit away from the first substrate and not covered by the first passivation layer.

[0150] S275 , forming a planarization layer, wherein the planarization layer covers the first passivation layer and the first electrode layer.

[0151] S276, forming a first conductive protrusion and a conductive column, wherein one end of the first conductive protrusion is connected to the first electrode layer, and the other end vertically extends to the surface of the planarization layer away from the first substrate side; the conductive column vertically penetrates the planarization layer and the first passivation layer.

[0152] In the method for preparing the first LED unit layer 20 , the implementation method and technical effect of each step and each structure can be referred to the aforementioned embodiment and will not be described in detail here.

[0153] In some embodiments, in combination Figure 18 to Figure 19 As shown, the step of bonding the first LED unit layer 20 to the substrate 10 includes: bonding the planarization layer 23 to the substrate 10, and bonding and electrically connecting the first conductive protrusions 24 and the conductive pillars 26 to the corresponding first contacts 11. The first substrate 27 and part of the first LED epitaxial layer 28 are removed until the surface of the first passivation layer 21 is exposed, so that the surfaces of the first passivation layer 21, the first LED unit 22 and the conductive pillars 26 facing away from the substrate 10 are flush.

[0154] Combination Fig.18 As shown, the first hybrid bonding is achieved by bonding the planarization layer 23 to the substrate 10, and bonding and electrically connecting the first conductive protrusion 24 and the conductive column 26 to the corresponding first contact 11. The processing technology is simple, the processing difficulty is reduced, the overall yield is improved, and the size of the display 1 is reduced.

[0155] Combination Fig.18 and Fig.19 As described above, the first substrate 27 and a portion of the first LED epitaxial layer 28 can be removed by chemical mechanical polishing (CMP) until the surface of the first passivation layer 21 is exposed, so that the surfaces of the first passivation layer 21, the first LED unit 22 and the conductive column 26 facing away from the substrate 10 are flush, in preparation for the second LED unit layer 30 to be bonded to the first LED unit layer 20.

[0156] During the CMP process, the first passivation layer 21 is used as the processing reference, that is, the processing is stopped when the surface of the first passivation layer 21 is exposed, which reduces the difficulty and cost of the processing technology, avoids or reduces the damage to the device due to excessive processing, and effectively protects the first LED unit 22 during the processing, thereby improving the overall yield.

[0157] Combination Figures 10 to 17 as well as Fig.28 As shown, in some embodiments, a method for preparing the second LED unit layer 30 is provided, comprising: S281. Provide a second substrate, on which a second LED epitaxial layer is disposed.

[0158] Combination Fig.10 As shown, the second substrate 36 provides support to make the entire second LED unit layer 30 structure more stable. For example, the second LED epitaxial layer 37 can be grown on the second substrate 36 so that the second substrate 36 provides stable support for the growth of the second LED epitaxial layer 37.

[0159] It should be noted that the material of the second substrate 36 is not limited, for example, it can be silicon, sapphire or gallium nitride. The material of the second LED epitaxial layer 37 is not limited, for example, it can be gallium nitride (GaN).

[0160] S282, etching the second LED epitaxial layer to form a plurality of second LED units.

[0161] Combination Fig.11 As shown, by etching the side of the second LED epitaxial layer 37 away from the second substrate 36, a plurality of mesa structures (MESA) are formed on the second LED epitaxial layer 37, each of which can form a complete second LED unit 31, so that the second LED unit 31 can be independently driven and emit light by the substrate 10. Specifically, the plurality of second LED units 31 are arranged at intervals.

[0162] S283, forming a second passivation layer, wherein the second passivation layer covers the surface of the etched second LED epitaxial layer and exposes a portion of the surface of the plurality of second LED units away from the second substrate.

[0163] Combination Fig.12 As shown, a second passivation layer 33 can be formed on the surface of the second LED epitaxial layer 37 facing away from the second substrate 36 by depositing material (for example, aluminum oxide or silicon dioxide), so that the second passivation layer 33 covers the surface of the second LED epitaxial layer 37 facing away from the second substrate 36 and the surfaces of the plurality of second LED units 31.

[0164] The second passivation layer 33 is etched to form a plurality of windows. Fig.12 G3 in the figure is used to indicate the window formed by etching the second passivation layer 33. The multiple windows expose the partial surface of the multiple second LED units 31 away from the second substrate 36 in a one-to-one correspondence, and prepare the structure for the subsequent electrical connection between the second LED units 31 and the second electrode layer 34.

[0165] S284. Form a second electrode layer on a side of the second passivation layer away from the second LED unit. The second electrode layer surrounds the side of the second LED unit and the side away from the second substrate. The second electrode layer covers the surface of the second LED unit away from the second substrate and not covered by the second passivation layer.

[0166] Combination Fig.13 As shown, a material is deposited on the side of the second passivation layer 33 away from the second substrate 36 to form a metal layer. The metal layer can cover the surface of the second LED unit 31 away from the second substrate 36 and not covered by the second passivation layer 33. The metal layer is processed by a photolithography patterning process to form a second electrode layer 34, so that the second electrode layer 34 is arranged around the side of the second LED unit 31 and the side of the second LED unit 31 away from the second substrate 36.

[0167] S285, forming a filling layer, wherein the filling layer covers the second passivation layer and the second electrode layer.

[0168] Combination Fig.14 As shown, after forming the second electrode layer 34 , a material (eg, silicon dioxide) is deposited on the surface of the second passivation layer 33 facing away from the second substrate 36 to form a filling layer 32 , so that the filling layer 32 covers the second passivation layer 33 and the second electrode layer 34 .

[0169] S286, forming a second conductive protrusion on the leveling layer, wherein one end of the second conductive protrusion is electrically connected to the second electrode layer, and the other end of the second conductive protrusion vertically extends to a surface of the leveling layer away from the second substrate side.

[0170] Combination Fig.15 As shown, the fill layer 32 is etched to form a plurality of through holes, and the structure is prepared for forming the second conductive protrusion 35. Fig.15 G4 in the figure is used to etch the through hole formed by the fill layer 32. Fig.16 As shown, in the plurality of through holes, the material (eg, copper) is filled, and the filling method is not limited, for example, it can be filled by deposition and electroplating (Cu Seed Deposition and Plating). Fig.17 As shown, after the filling material is formed, part of the filling layer 32 and part of the filling material are removed by chemical mechanical polishing (CMP) to obtain a second conductive protrusion 35 and the filling layer 32 after CMP processing, and one end of the second conductive protrusion 35 is connected to the second electrode layer 34, and the other end of the second conductive protrusion 35 extends vertically to the surface of the filling layer 32 after CMP processing that is away from the first substrate 27.

[0171] In some embodiments, Fig. 20 and Fig.21As shown, the micro-LED display 1 further includes a conductive column 26, and the step of bonding the second LED unit layer 30 to the first LED unit layer 20 includes: bonding the fill layer 32 to the first passivation layer 21, and bonding and electrically connecting the second conductive protrusion 35 to the end of the conductive column 26 facing away from the substrate 10. The second substrate 36 and part of the second LED epitaxial layer 37 are removed until the surface of the second passivation layer 33 is exposed, so that the second passivation layer 33 and the surface of the second LED unit 31 facing away from the substrate 10 are flush.

[0172] like Fig. 20 As shown, the second hybrid bonding is achieved by bonding the leveling layer 32 to the first passivation layer 21, and bonding and electrically connecting the second conductive protrusion 35 to the end of the conductive column 26 facing away from the substrate 10. The processing technology is simple, the processing difficulty is reduced, the overall yield is improved, and the size of the display 1 is reduced.

[0173] like Fig.21 As shown, the second substrate 36 and part of the second LED epitaxial layer 37 can be removed by chemical mechanical polishing (CMP) until the surface of the second passivation layer 33 is exposed, so that the second passivation layer 33 and the surface of the second LED unit 31 facing away from the substrate 10 are flush, providing structural preparation for the subsequent formation of the common electrode layer 40.

[0174] During the CMP process, the second passivation layer 33 is used as the processing reference, that is, the processing is stopped when the surface of the second passivation layer 33 is exposed, which reduces the difficulty and cost of the processing technology, avoids or reduces the damage to the device due to excessive processing, and effectively protects the second LED unit 31 during the processing, thereby improving the overall yield.

[0175] In some embodiments, Fig. 22 As shown, after the step of bonding the second LED unit layer 30 to the first LED unit layer 20, the preparation method further includes: etching the second LED unit layer 30 to expose the surface of the first LED unit 22 facing away from the substrate 10. A common electrode layer 40 is formed, the common electrode layer 40 at least covers the surface of the first LED unit 22 and the second LED unit 31 facing away from the substrate 10, and the common electrode layer 40 is electrically connected to the second contact of the substrate 10.

[0176] like Fig. 22As shown, by etching the second LED unit layer 30, a plurality of windows are formed in the second LED unit layer 30, and the plurality of windows expose the surfaces of the plurality of first LED units 22 facing away from the substrate 10 one by one. A material (such as ITO) is deposited on the surface of the second LED unit layer 30 facing away from the substrate 10 and on the surface of the plurality of windows of the second LED unit layer 30 to form a common electrode layer 40. The common electrode layer 40 is implemented to cover at least the surfaces of the plurality of first LED units 22 and the plurality of second LED units 31 facing away from the substrate 10. The common electrode layer 40 is electrically connected to the second contact of the substrate 10.

[0177] It can be understood that the specific connection method between the common electrode layer 40 and the second contact of the substrate 10 is not limited, as long as the common electrode layer 40 and the second contact of the substrate 10 can be electrically connected.

[0178] Combination Figures 2 to 22 as well as Fig.29 As shown, in a possible implementation, a method for preparing a micro light emitting diode display 1 is provided, comprising the following steps: S291. Provide a substrate.

[0179] S292. Prepare a first LED unit layer, the first LED unit layer comprising a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on a surface of the first LED unit layer facing away from the substrate side, and exposes the surfaces of the plurality of first LED units facing away from the substrate side; and the first passivation layer also at least covers the side surfaces of the plurality of first LED units.

[0180] S293, bonding the first LED unit layer to the substrate.

[0181] S294, preparing a second LED unit layer, the second LED unit layer comprising a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units.

[0182] S295, bonding the second LED unit layer to the first LED unit layer, wherein the leveling layer is bonded to the first passivation layer. The plurality of first LED units and the plurality of second LED units are electrically connected to the substrate respectively to achieve separate driving.

[0183] S296, etching the second LED unit layer to expose the surface of the first LED unit facing away from the substrate.

[0184] S297, forming a common electrode layer, wherein the common electrode layer at least covers the surface of the first LED unit and the second LED unit facing away from the substrate, and the common electrode layer is electrically connected to the second contact of the substrate.

[0185] In the preparation method of this embodiment, the implementation method and technical effect of each step and each structure are referred to the above embodiments and will not be repeated here.

[0186] In some embodiments, in combination Figure 1 , Fig.23 and Fig.24 As shown, the preparation method further includes: forming a protective layer 41, the protective layer 41 at least covers the common electrode layer 40. Forming a color conversion unit 42 on the protective layer 41, the color conversion unit 42 is located on part of the first LED unit 22 or part of the second LED unit 31.

[0187] Combination Fig.23 As shown, a material (eg, polyimide) is coated (eg, spin-coated) on the side of the common electrode layer 40 facing away from the substrate 10 to form a protective layer 41 , so that the protective layer 41 at least covers the common electrode layer 40 .

[0188] Combination Fig.24 As shown, the protective layer 41 is etched to form a plurality of windows in the protective layer 41, so as to provide a structural preparation for forming a color conversion unit 42. Fig.24 G5 in FIG. 4 is used to indicate a window formed by etching the protective layer 41. Figure 1 As shown, a material (e.g., quantum dot photoresist, QDPR) is filled in a plurality of windows of the protective layer 41 to form a plurality of color conversion units 42. The plurality of color conversion units 42 are located above some of the first LED units 22 among the plurality of first LED units 22, or above some of the second LED units 31 among the plurality of second LED units 31. Alternatively, among the plurality of color conversion units 42, a portion of the color conversion units 42 are located above some of the first LED units 22 among the plurality of first LED units 22, and another portion of the color conversion units are located above some of the second LED units 31 among the plurality of second LED units 31.

[0189] Combination Figures 1 to 24 as well as Fig.30 As shown, in a possible implementation, a method for preparing a micro light emitting diode display 1 is provided, comprising the following steps: S301. Provide substrate.

[0190] S302. Prepare a first LED unit layer, the first LED unit layer comprising a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on a surface of the first LED unit layer facing away from the substrate, and exposes a surface of the plurality of first LED units facing away from the substrate; and the first passivation layer also at least covers side surfaces of the plurality of first LED units.

[0191] S303, bonding the first LED unit layer to the substrate.

[0192] S304 , preparing a second LED unit layer, wherein the second LED unit layer includes a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units.

[0193] S305 , bonding the second LED unit layer to the first LED unit layer, wherein the leveling layer is bonded to the first passivation layer.

[0194] The plurality of first LED units 22 and the plurality of second LED units 31 are electrically connected to the substrate 10 respectively to achieve separate driving.

[0195] S306 , etching the second LED unit layer to expose the surface of the first LED unit facing away from the substrate.

[0196] S307 , forming a common electrode layer, wherein the common electrode layer at least covers the surfaces of the first LED unit and the second LED unit facing away from the substrate, and the common electrode layer is electrically connected to the second contact of the substrate.

[0197] S308 , forming a protective layer, wherein the protective layer at least covers the common electrode layer.

[0198] S309 , forming a color conversion unit on the protective layer, wherein the color conversion unit is located above a portion of the first LED unit or a portion of the second LED unit.

[0199] In the preparation method of this embodiment, the implementation method and technical effect of each step and each structure are referred to the above embodiments and will not be repeated here.

[0200] It should be noted that the steps involved in the preparation method of the embodiment of the present application do not limit the order in which the operations are performed. For example, step S302 and step S304 can be performed substantially in parallel. For another example, step S304 can be performed before step S303.

[0201] The embodiment of the present application further provides a display device. The display device includes a micro-LED display 1 as in any of the previous embodiments. Therefore, the display device has the beneficial effects of the micro-LED display 1 as in any of the previous embodiments, which will not be described in detail.

[0202] It should be noted that the micro light emitting diode display 1 or display device can be applied to augmented reality (AR) display devices, virtual reality (VR) display devices, near-eye display (NED) devices, head-up display (HUD) devices and other devices.

[0203] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A micro light emitting diode display, characterized in that: include: substrate; A first LED unit layer, bonded to the substrate, comprising a first passivation layer and a plurality of first LED units arranged at intervals; The first passivation layer is located on a surface of the first LED unit layer away from the substrate, and exposes surfaces of the first LED units away from the substrate; and the first passivation layer also at least covers side surfaces of the first LED units; A second LED unit layer, bonded to the first LED unit layer, comprising a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units, wherein the filling layer is bonded to the first passivation layer; Wherein, a plurality of the first LED units and a plurality of the second LED units are electrically connected to the substrate respectively to achieve separate driving.

2. The micro light emitting diode display according to claim 1, characterized in that: The substrate includes a plurality of first contacts, and the first LED unit layer further includes: A planarization layer, disposed on a side of the first passivation layer facing the substrate and bonded to the substrate; A first conductive protrusion, wherein one end of the first conductive protrusion is electrically connected to the first LED unit, and the other end of the first conductive protrusion is bonded and electrically connected to the corresponding first contact.

3. The micro light emitting diode display according to claim 1, characterized in that: The first LED unit layer further comprises: A first electrode layer is disposed on a side of the first passivation layer away from the first LED unit and surrounds a side of the first LED unit and a side facing the substrate; Furthermore, the first electrode layer covers a surface of the first LED unit that faces the substrate and is not covered by the first passivation layer, and the first electrode layer reflects light emitted by the first LED unit.

4. The micro light emitting diode display according to claim 1, characterized in that: The second LED unit layer further includes: The second passivation layer is disposed on the surface of the filling layer away from the substrate and exposes the surfaces of the second LED units away from the substrate. The second passivation layer also at least covers the side surfaces of the second LED units.

5. The micro light emitting diode display according to claim 4, characterized in that: The second LED unit layer further includes: A second electrode layer is disposed on a side of the second passivation layer away from the second LED unit, and is disposed around a side of the second LED unit and a side facing the substrate; Furthermore, the second electrode layer covers a surface of the second LED unit that faces the substrate and is not covered by the second passivation layer, and the second electrode layer reflects light emitted by the second LED unit.

6. The micro light emitting diode display according to claim 1, characterized in that: Also includes: A conductive column vertically penetrates the first LED unit layer, one end of the conductive column is electrically connected to the substrate, and the other end of the conductive column is electrically connected to the corresponding second LED unit.

7. The micro light emitting diode display according to claim 6, characterized in that: The second LED unit layer further includes: a second conductive protrusion, wherein the second conductive protrusion is electrically connected to the second LED unit; Wherein, the conductive column is electrically connected to the second LED unit through the second conductive protrusion.

8. The micro light emitting diode display according to claim 1, characterized in that: The first LED unit and the second LED unit respectively include a first doped semiconductor layer, an active layer and a second doped semiconductor layer which are stacked, and the first doped semiconductor layer is close to the substrate; A surface of the second doped semiconductor layer of the first LED unit facing away from the substrate is flush with a surface of the first passivation layer facing away from the substrate.

9. The micro light emitting diode display according to claim 1, characterized in that: The substrate includes at least one second contact, and the micro light emitting diode display further includes: The common electrode layer is electrically connected to the surfaces of the first LED unit and the second LED unit that are away from the substrate, and the common electrode layer is electrically connected to the second contact point.

10. The micro light emitting diode display according to claim 1, characterized in that: Also includes: a plurality of color conversion units, located on part of the first LED units or part of the second LED units, the color conversion units being used to convert a first color light emitted by the first LED unit or a second color light emitted by the second LED unit into a third color light, wherein the first color light, the second color light and the third color light are different; Wherein, at least one first LED unit, at least one adjacent second LED unit and at least one adjacent color conversion unit form a full-color pixel point.

11. The micro light emitting diode display according to claim 1, characterized in that: Also includes: A third LED unit layer is bonded to the second LED unit layer, and includes a plurality of third LED units arranged at intervals, wherein vertical projections of the first LED unit, the second LED unit, and the third LED unit on the substrate do not overlap; Wherein, at least one first LED unit, at least one adjacent second LED unit, and at least one adjacent third LED unit form a full-color pixel point.

12. A method for preparing a micro light emitting diode display, characterized in that: The steps include: providing a substrate; Prepare a first LED unit layer, the first LED unit layer comprising a first passivation layer and a plurality of first LED units arranged at intervals; the first passivation layer is located on a surface of the first LED unit layer away from the substrate side, and exposes a surface of the plurality of first LED units away from the substrate side; and the first passivation layer also at least covers side surfaces of the plurality of first LED units; bonding the first LED unit layer to the substrate; Prepare a second LED unit layer, wherein the second LED unit layer includes a plurality of second LED units arranged at intervals and a filling layer located between adjacent second LED units; Bonding the second LED unit layer to the first LED unit layer, wherein the fill layer is bonded to the first passivation layer; Wherein, a plurality of the first LED units and a plurality of the second LED units are electrically connected to the substrate respectively to achieve separate driving.

13. The preparation method according to claim 12, characterized in that: The steps of preparing the first LED unit layer include: Providing a first substrate, on which a first LED epitaxial layer is disposed; Etching the first LED epitaxial layer to form a plurality of first LED units; A first passivation layer is formed, wherein the first passivation layer covers the surface of the etched first LED epitaxial layer and exposes a portion of the surface of the plurality of first LED units away from the first substrate.

14. The preparation method according to claim 13, characterized in that: The step of preparing the first LED unit layer further includes: A first electrode layer is formed on a side of the first passivation layer away from the first LED unit, the first electrode layer is arranged around a side of the first LED unit and a side away from the first substrate, and the first electrode layer also covers a surface of the first LED unit away from the first substrate and not covered by the first passivation layer; forming a planarization layer, wherein the planarization layer covers the first passivation layer and the first electrode layer; A first conductive protrusion and a conductive column are formed, wherein one end of the first conductive protrusion is connected to the first electrode layer, and the other end vertically extends to the surface of the planarization layer away from the first substrate side; the conductive column vertically penetrates the planarization layer and the first passivation layer.

15. The preparation method according to claim 14, characterized in that: The substrate includes a plurality of first contacts, and the step of bonding the first LED unit layer to the substrate includes: Bonding the planarization layer to the substrate, and bonding and electrically connecting the first conductive protrusions and the conductive pillars to the corresponding first contacts; The first substrate and a portion of the first LED epitaxial layer are removed until the surface of the first passivation layer is exposed, so that the first passivation layer, the first LED unit, and the surface of the conductive column facing away from the substrate are flush.

16. The preparation method according to claim 12, characterized in that: The steps of preparing the second LED unit layer include: Providing a second substrate, on which a second LED epitaxial layer is disposed; Etching the second LED epitaxial layer to form a plurality of second LED units; forming a second passivation layer, wherein the second passivation layer covers the surface of the etched second LED epitaxial layer and exposes a portion of the surface of a plurality of second LED units away from the second substrate; A second electrode layer is formed on a side of the second passivation layer away from the second LED unit, the second electrode layer is arranged around a side of the second LED unit and a side away from the second substrate, and the second electrode layer covers a surface of the second LED unit away from the second substrate and not covered by the second passivation layer; forming a filling layer, wherein the filling layer covers the second passivation layer and the second electrode layer; A second conductive protrusion is formed on the leveling layer, one end of the second conductive protrusion is electrically connected to the second electrode layer, and the other end of the second conductive protrusion vertically extends to a surface of the leveling layer away from the second substrate.

17. The preparation method according to claim 16, characterized in that: The micro light emitting diode display further includes a conductive column, and the step of bonding the second LED unit layer to the first LED unit layer includes: Bonding the fill layer to the first passivation layer, and bonding and electrically connecting the second conductive protrusion to an end of the conductive column facing away from the substrate; The second substrate and a portion of the second LED epitaxial layer are removed until the surface of the second passivation layer is exposed, so that the second passivation layer is flush with the surface of the second LED unit facing away from the substrate.

18. The preparation method according to claim 12, characterized in that: After the step of bonding the second LED unit layer to the first LED unit layer, the preparation method further comprises: Etching the second LED unit layer to expose the surface of the first LED unit facing away from the substrate; A common electrode layer is formed, wherein the common electrode layer at least covers the surface of the first LED unit and the second LED unit which are away from the substrate, and the common electrode layer is electrically connected to the second contact of the substrate.

19. The preparation method according to claim 18, characterized in that: Also includes: forming a protective layer, wherein the protective layer at least covers the common electrode layer; A color conversion unit is formed on the protection layer, and the color conversion unit is located above a portion of the first LED unit or a portion of the second LED unit.

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