Pixel unit, method for manufacturing the same, microdisplay, and individual element

Abstract

According to the present invention, a pixel unit, a method for manufacturing the pixel unit, a microdisplay, and an individual element are provided. The pixel unit includes a backplane, a display unit, a cathode electrical connection structure, and at least one anode electrical connection structure. The display unit includes at least one element layer including a P-type contact layer, a pixel layer, and an N-type contact layer sequentially stacked. The P-type contact layer is located on one side facing the backplane of the element layer. Any anode electrical connection structure and the P-type contact layer of the corresponding element layer are electrically connected. The cathode electrical connection structure and the N-type contact layer of any element layer are electrically connected. The pixel unit according to the present invention can achieve color display by sequentially integrating at least two layers of element layers on the backplane. Compared with the integrated pixel structure arranged along the horizontal direction, the pixel unit according to the present invention occupies less space in the horizontal direction and can achieve high-density color display.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and particularly to pixel units, manufacturing methods thereof, microdisplays, and individual devices.

Background Art

[0002] Micro-LED displays have numerous advantages compared to conventional display technologies such as LCD and OLED, and are regarded as the core technology of the next generation. Although there is a high likelihood that Micro-LED displays will be applied in multiple fields such as watches, televisions, projection, virtual reality, augmented reality, and hybrid reality, new requirements are being demanded for chip manufacturing, dimensions, structure, yield, driving, etc. of these applications. It is difficult for conventional LED manufacturing methods to meet these requirements. By enhancing alignment, these requirements can be satisfied.

[0003] In the field of Micro-LED, colorization is a major challenge. Currently, the mainstream Micro-LED colorization technologies include three primary colors, color conversion, prism synthetic light, etc. The realization of colorization is based on three colors in a planar structure, and it is difficult to further compress the element dimensions and display an ultra-high-density pixel matrix.

[0004] Although it is possible to apply conventional LED chips and their display manufacturing methods to Mini LEDs, in the case of Micro-LEDs, both the dimensions and thickness are at the μm level, which is far too different from conventional LEDs of several hundred or several thousand μm. The number of chips used during operation is extremely large, and it is difficult to manufacture Micro-LEDs using conventional manufacturing methods. Taking the display of a smartphone as an example, the display of a smartphone with a 1080P resolution has more than 2 million pixels (1920×1080). And each pixel is composed of three sub-pixels of red, green, and blue. That is, the display of a smartphone with a 1080 resolution requires LEDs composed of more than 6 million sub-pixels. It takes about one year to manufacture such a display, and its manufacturing cost is extremely high.

[0005] Currently, for Micro-LED chips, there are mainly two methods: mass transfer and monolithic integration. Mass transfer uses pick and place, but different from picking one or several chips at a time like conventional LEDs, mass transfer picks and moves a large number of chips at once. Monolithic integration is a method in which a densely arranged LED matrix area is formed, or after the LEDs on the wafer are arranged, the metal melting point is joined to the drive circuit, and it has a higher degree of integration.

[0006] At present, methods for realizing colorized Micro-LED display chips include mass transfer, horizontal display of misaligned bonding (for example, CN110462850A), and vertical display of aligned bonding. In the currently disclosed mass transfer and horizontal display technologies of misaligned bonding, problems such as spatial waste and optical interference within pixels generally exist. Spatial waste occurs in the horizontal arrangement of red, green, and blue three colors, resulting in a loss of display pixel density. In the case of aligned vertical stacking integration, the requirements for alignment are extremely high, the cost is extremely high, and it is difficult to guarantee the alignment accuracy. As described in the published literature, when the pixel size increases or decreases by 1 μm, when manufacturing ultra-small pixels, it is difficult to accept the deviation value of alignment. Since single color devices are manufactured first, there are step differences in the element body. In the bonding process, matrix cracks or fractures due to the step differences occur, affecting the yield.

[0007] Therefore, there is a need for a micro-sized pixel unit with a high pixel density.

Summary of the Invention

[0008] An object of the present invention is to provide a pixel unit, a manufacturing method thereof, a microdisplay, and an individual element that can realize ultra-high density and μm-level colorized display.

[0009] To achieve the above object, according to a first aspect of the present invention, there is provided a pixel unit including a backplane, a display unit, a cathode electrical connection structure, and at least one anode electrical connection structure. The display unit is provided on the backplane. One surface of the cathode electrical connection structure and at least one anode electrical connection structure spaced apart from the backplane is provided on the display unit so as to be embedded. The display unit includes at least one element layer including a P-type contact layer, a pixel layer, and an N-type contact layer sequentially stacked. The P-type contact layer is located on one side of the element layer facing the backplane. Any of the anode electrical connection structures and the P-type contact layer of the corresponding element layer are electrically connected. The cathode electrical connection structure and the N-type contact layer of any of the element layers are electrically connected.

[0010] Also, in a preferred example, any of the anode electrical connection structures is connected to the backplane, and at least one of the anode electrical connection structures includes a first anode electrical connection structure including a first partial structure and a second partial structure that are sequentially connected. At least one of the element layers includes a first element layer including a first bonding layer, a first P-type contact layer, a first pixel layer, and a first N-type contact layer that are sequentially stacked. The first P-type contact layer is located on one side of the first element layer close to the backplane. The first partial structure is provided in the first bonding layer and the first P-type contact layer so as to be embedded. The second partial structure is provided in the first pixel layer so that a part thereof is embedded and is electrically connected to the first P-type contact layer.

[0011] Also, in a preferred example, an end face area of the second partial structure is larger than an end face area of the first partial structure. A first flange is formed at a connection portion between the second partial structure and the first partial structure, and the first flange is connected to the first P-type contact layer.

[0012] Also, in a preferred example, at least one of the anode electrical connection structures further includes a second anode electrical connection structure. The display unit further includes a second element layer stacked on a surface of the first element layer on one side spaced apart from the backplane. The second element layer includes a second bonding layer, a second P-type contact layer, a second pixel layer, and a second N-type contact layer that are sequentially stacked. The second bonding layer is connected to the first pixel layer. The second anode electrical connection structure includes a second flange connected to the second P-type contact layer.

[0013] Also, in a preferred example, the second N-type contact layer is provided directly above the first N-type contact layer.

[0014] Also, in a preferred example, the first N-type contact layer has a convex structure and is provided in the second bonding layer so as to be embedded.

[0015] Also, in a preferred example, the cathode electrical connection structure includes a third partial structure provided in the second element layer so as to be embedded and having one end connected to the first N-type contact layer.

[0016] Also, in a preferred example, the cathode electrical connection structure further includes a fourth partial structure having one end connected to the backplane and the other end penetrating the first element layer and connected to the third partial structure.

[0017] Also, in a preferred example, the second bonding layer includes a second bonding layer main body and a functional layer provided between the second bonding layer main body and the first pixel layer.

[0018] Also, in a preferred example, at least one of the anode electrical connection structures further includes a third anode electrical connection structure, the display unit includes a third element layer laminated on one surface of the second element layer separated from the first element layer, the third element layer includes a third bonding layer, a third P-type contact layer, a third pixel layer, and a third N-type contact layer laminated in sequence, the third bonding layer is connected to the second pixel layer, and the anode electrical connection structure includes a third flange connected to the third P-type contact layer.

[0019] Also, in a preferred example, the cathode electrical connection structure further includes a fifth partial structure connected to the third partial structure and provided in the third element layer so as to be embedded. By making the end face area of the fifth partial structure larger than the end face area of the third partial structure, a fourth flange is formed at the connection portion between the fifth partial structure and the third partial structure, and the fourth flange is connected to the second N-type contact layer.

[0020] Also, in a preferred example, the second N-type contact layer has a convex structure and is provided in the third bonding layer so as to be embedded.

[0021] Also, in a preferred example, both the second bonding layer and the third bonding layer are made of a transparent material.

[0022] Further, in a preferred example, a passivation layer is further included, with a part thereof being provided in close contact with the outer surfaces of the display unit and the backplane, a part thereof being provided in close contact between at least one of the anode electrical connection structures and the display unit, and a part thereof being provided in close contact between the cathode electrical connection structure and the display unit.

[0023] Further, in a preferred example, at least one through hole is formed in the passivation layer, which is located between any of the anode electrical connection structures and the corresponding P-type contact layer, and between the cathode electrical connection structure and the corresponding N-type contact layer.

[0024] Further, in a preferred example, the passivation layer is composed of a transparent material.

[0025] Further, in a preferred example, the first pixel layer is AlGaInP or InGaN red light compound epitaxy, the second pixel layer is InGaN green light compound epitaxy, and the third pixel layer is InGaN blue light compound epitaxy.

[0026] Further, according to a second aspect of the present invention, there is provided a method for manufacturing a pixel unit, including preparing a backplane, forming a display unit by laminating at least one element layer on the backplane, the element layer including a P-type contact layer, a pixel layer, and an N-type contact layer laminated in sequence, the P-type contact layer being located on one side of the element layer facing the backplane, etching one surface of the display unit separated from the backplane to form a cathode electrical connection channel and at least one anode electrical connection channel, and filling the cathode electrical connection channel and at least one of the anode electrical connection channels with metal to form a cathode electrical connection structure and at least one anode electrical connection structure, the cathode electrical connection structure being electrically connected to the N-type contact layer of any of the element layers, and any of the anode electrical connection structures being electrically connected to the P-type contact layer of the corresponding element layer.

[0027] Also, in a preferred example, at least one of the element layers includes a first element layer. Forming a display unit by laminating at least one element layer on the backplane includes forming a first bonding layer by coating a bonding material on the surface of the backplane and the surface of the P-type contact layer of a previously prepared first compound semiconductor wafer, removing the substrate of the first compound semiconductor wafer, and thinning the first compound semiconductor wafer to expose a first N-type contact layer as a convex structure.

[0028] Also, in a preferred example, at least one of the element layers further includes a second element layer and a third element layer. After completing the first element layer, forming a display unit by laminating at least one element layer on the backplane further includes forming the display unit by laminating the second element layer and the third element layer on one surface of the first element layer that is separated from the backplane.

[0029] Also, in a preferred example, forming a cathode electrical connection channel and at least one anode electrical connection channel by etching one surface of the display unit that is separated from the backplane includes initially etching the one surface of the display unit that is separated from the backplane by pattern dry etching, and further etching the display unit that has been initially etched by pattern wet etching to expose the backplane to form at least one anode electrical connection channel and to expose the N-type contact layer to form the cathode electrical connection channel.

[0030] In a preferred example, forming the cathode electrical connection channel and at least one of the anode electrical connection channels by etching one surface of the display unit that is spaced apart from the backplane includes initial depth etching of one surface of the display unit that is spaced apart from the backplane by patterned dry etching, and depth etching of the display unit after the initial depth etching by patterned wet etching to expose the backplane and form at least one anode electrical connection channel and the cathode electrical connection channel.

[0031] In a preferred example, forming the cathode electrical connection structure and at least one of the anode electrical connection structures by filling the cathode electrical connection channel and at least one of the anode electrical connection channels with metal includes forming a passivation layer on the outer surfaces of the display unit and the backplane and on the inner walls of the cathode electrical connection channel and at least one of the anode electrical connection channels, forming via holes located between any of the anode electrical connection structures and the corresponding P-type contact layer and between the cathode electrical connection structure and the corresponding N-type contact layer by patterned etching, and configuring the cathode electrical connection structure and at least one of the anode electrical connection structures by filling the cathode electrical connection channel and at least one of the anode electrical connection channels with metal by sputtering, electroplating, chemical plating, or evaporation.

[0032] According to a third aspect of the present invention, there is provided a microdisplay including a driving backplane including a driving circuit and an input / output interface, a display area provided on the driving backplane, the display area including at least two display units arranged in an array and described in any one of claims 1 to 7 and 9 to 17, and a peripheral common cathode provided along the circumferential direction of the display area and connected to the cathode electrical connection structure of any of the display units.

[0033] Also, in a preferred example, a drive circuit is integrated in the backplane, and the drive circuit corresponding to any of the pixel units further includes at least one anode connected to any of the anode electrical connection structures.

[0034] Also, in a preferred example, it further includes an insulating layer and a transparent conductive layer provided in close contact with the display area in order from the inside to the outside. The transparent conductive layer is connected to the surrounding common cathode, at least one blank is formed in the insulating layer, and the cathode electrical connection structure is connected to the transparent conductive layer through the blank of the insulating layer.

[0035] According to a fourth aspect of the present invention, there is provided an individual element backplane, an element body provided on the individual element backplane, the element body including at least two display units described in any of the first aspects arranged in an array, at least two pads including a cathode pad and at least one anode pad, at least a part of any of the anode pads and at least a part of the cathode pad are provided on the individual element backplane so as to be embedded, any of the anode electrical connection structures is connected to the corresponding anode pad, and the cathode electrical connection structure is connected to the corresponding cathode pad.

[0036] Compared with the prior art, the present invention has the following excellent effects.

[0037] According to the present invention, there is provided a pixel unit including a backplane, a display unit, a cathode electrical connection structure, and at least one anode electrical connection structure. The display unit is provided on the backplane. One surface of the cathode electrical connection structure and the at least one anode electrical connection structure, which is spaced apart from the backplane, is provided on the display unit so as to be embedded. The display unit includes at least one element layer including a P-type contact layer, a pixel layer, and an N-type contact layer sequentially stacked. The P-type contact layer is located on one side facing the backplane of the element layer. Any anode electrical connection structure and the P-type contact layer of the corresponding element layer are electrically connected. The cathode electrical connection structure and the N-type contact layer of any element layer are electrically connected. In the pixel unit according to the present invention, by stacking at least two layers of element layers on the backplane, color display can be realized. Therefore, compared with a pixel structure arranged and integrated horizontally, the space occupied by the pixel unit according to the present invention in the horizontal direction is small, and ultra-high-density color Micro-LED display can be realized. Thereby, a smaller display size at the same resolution or a higher resolution at the same display size can be realized. In the present invention, a plurality of element layers stacked along the stacking direction share the same cathode electrical connection structure, so that the ratio of the area occupied by the light-emitting region can be increased, and the influence of the size effect can be reduced.

[0038] In addition, the first anode electrical connection structure includes a first partial structure and a second partial structure connected in sequence. The end face area of the second partial structure is larger than that of the first partial structure. At the connection location between the second partial structure and the first partial structure, a first flange is formed. The image unit further includes a passivation layer, a part of which is provided in close contact with the outer surfaces of the display unit and the backplane, a part of which is provided in close contact between at least one anode electrical connection structure and the display unit, and a part of which is provided in close contact between the cathode electrical connection structure and the display unit. The anode electrode connection structure according to the present invention can realize the electrical connection between the anode electrical connection structure and the P-type contact layer or the electrical connection between the cathode electrical connection structure and the N-type contact layer by forming a flange structure due to the change in diameter, simplify the structure, and reduce the difficulty of the manufacturing method.

[0039] According to the present invention, there is provided a method for manufacturing a pixel unit, including preparing a backplane, forming a display unit by laminating at least one element layer on the backplane, the element layer including a P-type contact layer, a pixel layer, and an N-type contact layer laminated in sequence, the P-type contact layer being located on one side facing the backplane of the element layer, etching one side surface of the display unit spaced apart from the backplane of the display unit to form a cathode electrical connection channel and at least one anode electrical connection channel, and filling the cathode electrical connection channel and the at least one anode electrical connection channel with metal to form a cathode electrical connection structure and at least one anode electrical connection structure, the cathode electrical connection structure being electrically connected to the N-type contact layer of any element layer, and any anode electrical connection structure being electrically connected to the P-type contact layer of the corresponding element layer. The method for manufacturing a pixel unit according to the present invention uses a method of laminating first and then patterning, so that the extremely high cost of alignment bonding by a semiconductor process can be eliminated, the deviation of positioning accuracy can be avoided, the lamination of pixels with smaller dimensions in the process can be realized, the difficulty of the process can be reduced, and the process cost can be saved.

[0040] According to the present invention, it is only necessary to obtain at least one of the above-described effects.

Brief Description of the Drawings

[0041]

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Modes for Carrying Out the Invention

[0042] In order to make the object, technical means and advantages of the present application clearer, hereinafter, with reference to the drawings in the embodiments of the present application, the technical means in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts shall all be included in the protection scope of the present application.

[0043] In the description of the present application, the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, for the convenience of description and simplification of the description, and does not indicate or imply that the device or element mentioned must have a specific orientation and must be constructed and operated in a specific orientation. Therefore, it should not be understood as limiting the present application. Also, the terms "first" and "second" are used only for the purpose of description and do not indicate or imply relative importance or implicitly indicate the number of the indicated technical features. Therefore, the features limited as "first" and "second" may include one or more of the said features explicitly or implicitly. In the description of the present application, unless otherwise specified, "a plurality" means two or more.

[0044] In the description of the present application, unless there are specific explicit regulations and limitations, the terms "attachment", "connection to each other", and "connection" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection. It may be a mechanical connection or an electrical connection. It may be a direct connection or an indirect connection through an intermediate medium, or a communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood case by case.

[0045] Example 1 As shown in FIGS. 1 and 2, according to this embodiment, there is provided a pixel unit 100 which is the minimum light-emitting unit of the individual element 300 shown in FIGS. 3 to 5, or the minimum light-emitting unit of the microdisplay 200 as shown in FIG. 6.

[0046] As shown in FIG. 2, the pixel unit 100 includes a backplane 10, a display unit 20, a cathode electrical connection structure 30, and at least one anode electrical connection structure. The display unit 20 is provided on the backplane 10, and one surface of the cathode electrical connection structure 30 and at least one anode electrical connection structure spaced apart from the backplane 10 is provided on the display unit 20 so as to be embedded. Any anode electrical connection structure is connected to the backplane 10.

[0047] The display unit 20 includes at least one element layer stacked on the backplane 10, thereby forming a Wafer Level Vertical Stack Pixel (WLVSP). Any element layer includes a P-type contact layer, a pixel layer, and an N-type contact layer stacked in sequence, and the P-type contact layer is located on one side facing the backplane 10 of the element layer. Any anode electrical connection structure and the P-type contact layer of the corresponding element layer are electrically connected, and the cathode electrical connection structure and the N-type contact layer of any element layer are electrically connected. The number of anode electrical connection structures included in the pixel unit of this embodiment corresponds to the number of element layers.

[0048] In this embodiment, the number of element layers included in the display unit 20 is not limited, and it may be one layer, two layers, or three or more layers. When the number of element layers is two or more, the light-emitting compound epitaxies included in any two element layers may be the same or different. When the light-emitting compound epitaxies included in any two element layers are the same, the brightness improvement of the same color light source can be realized, or the yield of the pixel unit can be improved by forming a spare redundant element layer. When the light-emitting compound epitaxies included in any two element layers are different, for example, full-color display or color display such as red, green, and blue primary color pixels can be realized.

[0049] For the sake of easy explanation, in this embodiment, it is exemplified and described in detail that the pixel unit 100 is a pixel of the three primary colors of red, green, and blue. The display unit 20 includes a first element layer 40 that emits red light, a second element layer 50 that emits green light, and a third element layer 60 that emits blue light.

[0050] Any of the element layers in this embodiment may be a normal shape such as a quadrilateral, hexagon, octagon, circle, or a combination of figures, without further limitation.

[0051] Specifically, the backplane 10 is a source-less backplane or a source-backplane with an integrated driving circuit. When the pixel unit 100 is used for a microdisplay, the backplane 10 is preferably a source-backplane with at least one anode provided in the driving circuit, one or more source-backplane driving backplanes and semi-source-backplane driving backplanes such as thin-film transistors (TFTs), LTPS low-temperature polysilicon, CMOS integrated circuits, and high-mobility transistors HEMT. For example, when a CMOS integrated circuit backplane is selected, for R, G, and B, top metal is provided corresponding to the anode surface respectively. The circuit diagrams of the driving circuits of the CMOS integrated circuit backplane are shown in FIGS. 7 to 9. As shown in FIGS. 8 and 9, after further stacking two layers of red light element layers connected in parallel or in series, the green light element layer and the blue light element layer are further stacked. The circuit of each element layer may include an active, passive, or semi-passive control circuit. A circuit example is shown in FIG. 10. The circuit diagrams according to this embodiment are merely simple schematic diagrams. At least one anode according to this embodiment is arranged on the same straight line, or in a triangular arrangement, or in a matrix arrangement. Any anode is located in the middle or at the edge of the backplane 10, but is not limited thereto. When the pixel unit is used for an individual element, the backplane is preferably a source-less backplane made of a material such as PCB, sapphire, glass, Si, etc. Note that the source-less backplane realizes the connection with the power supply through a downstream packaging process.

[0052] As shown in FIGS. 2 and 4, the first element layer 40 includes a first bonding layer 41, a first P-type contact layer 42, a first pixel layer 43, and a first N-type contact layer 44 that are stacked in sequence. The first P-type contact layer 42 is located on one side close to the backplane 10 of the first element layer 40. The second element layer 50 is stacked on the surface of the first element layer 40 on one side that is spaced apart from the backplane 10. The second element layer 50 includes a second bonding layer 51, a second P-type contact layer 52, a second pixel layer 53, and a second N-type contact layer 54 that are stacked in sequence. The second bonding layer 51 is connected to the first pixel layer 43. The third element layer 60 is stacked on the surface of the second element layer 50 on one side that is spaced apart from the first element layer 40. The third element layer 60 includes a third bonding layer 61, a third P-type contact layer 62, a third pixel layer 63, and a third N-type contact layer 64 that are stacked in sequence. The third bonding layer 61 is connected to the second pixel layer 53.

[0053] In order for light rays to pass through easily, it is preferable that both the second bonding layer 51 and the third bonding layer 61 are made of a transparent bonding material. The transparent bonding material may be, for example, a transparent derivative made of an organic transparent conductor such as SU8, or may be a transparent derivative made of an inorganic transparent conductor such as SiO2, Si3N4, sapphire, etc., or may be a semiconductor transparent material such as ITO, GaAs, GaP, GaN, etc.

[0054] Each P-type contact layer includes an ohmic contact and a Schottky contact, and may be a transparent conductive material such as ITO, or may be a stack or alloy of metal materials such as Au, Ag, Mg, Be, Zn, etc., and it is preferable to be ITO. The N-type contact layer may be composed of one or more stacks and alloys of Cr, Al, Ni, Ti, Au, Ge, ITO, ZnO, etc. In the case of a stack, for example, AuGeNiAu can be mentioned. It is preferable to form an ITO film on the first compound semiconductor wafer by methods such as evaporation and sputtering for each P-type contact layer. The ITO has a film thickness of 500 nm and forms an ohmic contact in an environment where N2 is annealed at a high temperature of 500 °C.

[0055] It is preferable to perform roughening treatment on the surface of the N-type contact layer so that structures such as recesses and protrusions randomly or regularly distributed are formed on the surface of the N-type contact layer.

[0056] The first pixel layer 43 is preferably AlGaInP or InGaN red light compound epitaxy, the second pixel layer 53 is preferably InGaN green light compound epitaxy, and the third pixel layer 63 is preferably InGaN blue light compound epitaxy.

[0057] The second junction layer 51 includes a functional layer 511 and a second junction layer main body 512, and the functional layer 511 is preferably provided between the second junction layer main body 512 and the first pixel layer 43. The functional layer 511 is at least one of a light sieve, a Bragg reflector, an ODR structure, and a contact electrode. The functional layer 511 is preferably a light filter material provided on the first N-type contact layer 44, and may be a colored rubber of an organic material, or may be a laminate of silicon oxide and titanium oxide films of an inorganic material, and permits the passage of red light wavelengths.

[0058] Corresponding to the first element layer 40, the second element layer 50, and the third element layer 60, the pixel unit 100 includes a first anode electrical connection structure 71, a second anode electrical connection structure 72, and a third anode electrical connection structure 73. The first anode electrical connection structure 71, the second anode electrical connection structure 72, and the third anode electrical connection structure 73 are all connected to the backplane 10 and are electrically connected to the P-type contact layers of the corresponding element layers. That is, the first anode electrical connection structure 71, the second anode electrical connection structure 72, and the third anode electrical connection structure 73 are electrically connected to the first P-type contact layer 42, the second P-type contact layer 52, and the third P-type contact layer 62, respectively.

[0059] Specifically, the first anode electrical connection structure 71 includes a first sub-structure 711 and a second sub-structure 712 connected in sequence. The first sub-structure 711 is provided in the first bonding layer 41 and the first P-type contact layer 42 so as to be embedded, and one end thereof is connected to the backplane 10. The second sub-structure 712 is provided in the first pixel layer 43 so that a part thereof is embedded, and is electrically connected to the first P-type contact layer 42. At the connection point between the first sub-structure 711 and the second sub-structure 712, the end area of the second sub-structure 712 is larger than the end area of the first sub-structure 711 so that a first flange 713 connected to the first P-type contact layer 42 is formed. Of course, in order to improve the structural stability between the first anode electrical connection structure 71 and each element layer, at the connection point between the first anode electrical connection structure 71 and the second P-type contact layer 52, or at the connection point between the first anode electrical connection structure 71 and the third P-type contact layer 62, a flange structure may be similarly formed. On the premise that the first element layer 40 and the second element layer 50 are different compound epitaxies, in a state where the first flange 713 and the first P-type contact layer 42 are electrically connected, the first anode electrical connection structure 71 is insulated from the P-type contact layers of the other element layers. Of course, when any two element layers have the same compound epitaxy, the two flanges formed in the anode electrical connection structure may be electrically connected to the corresponding P-type contact layers respectively. Similarly, the second anode electrical connection structure 72 includes a second flange 721 electrically connected to the second P-type contact layer 52. The third anode electrical connection structure 73 includes a third flange 731 electrically connected to the third P-type contact layer 62.

[0060] The first N-type contact layer 44, the second N-type contact layer 54, and the third N-type contact layer 64 all include a protrusion structure. The first N-type contact layer 44 is provided in the second bonding layer 51 so as to be embedded, and the second N-type contact layer 54 is provided in the third bonding layer 61 so as to be embedded. The first N-type contact layer 44, the second N-type contact layer 54, and the third N-type contact layer 64 are preferably located in the vertical direction of the same backplane 10. That is, in order to facilitate the construction of the cathode electrical connection structure and reduce the process difficulty, the third N-type contact layer 64 is located directly above the second N-type contact layer 54, and the second N-type contact layer 54 is located directly above the first N-type contact layer 44. Further, the projections of the first N-type contact layer 44, the second N-type contact layer 54, and the third N-type contact layer 64 on the backplane 10 are semi-circular with the same center of the circle, and the radii from the first N-type contact layer 44 to the third N-type contact layer 64 gradually increase.

[0061] In a specific embodiment, the cathode electrical connection structure 30 includes a third sub-structure 31. The third sub-structure 31 is provided in the second element layer 72 so as to be embedded, and one end thereof is connected to the first N-type contact layer 44. In such a structure, when the pixel unit 100 is used in a microdisplay, the backplane 10 is not provided with a cathode, and the cathode is provided on the outer periphery or the surface of the display unit.

[0062] In another preferred embodiment, the cathode electrical connection structure 30 includes a fourth sub-structure 32. One end of the fourth sub-structure 32 is connected to the backplane 10, and the other end thereof penetrates the first element layer 71 and is connected to the third sub-structure 31. When the pixel unit 100 is used in a microdisplay, the fourth sub-structure 32 is insulated from both the backplane 10 and the first element layer 71. When the pixel unit 100 is used in an individual element, the fourth sub-structure is insulated only from the first element layer 71.

[0063] Furthermore, the cathode electrical connection structure 30 includes a fifth sub-structure 33 connected to the third sub-structure 31. The fifth sub-structure 33 is provided in the third element layer 60 so as to be embedded. At the connection location between the fifth sub-structure 33 and the third sub-structure 31 where the fourth flange 34 connected to the second N-type contact layer 54 is formed, the end face area of the fifth sub-structure 33 is larger than the end face area of the third sub-structure 31.

[0064] In such a structure, the pixel unit 100 further includes a passivation layer 80. The passivation layer 80 is composed of a transparent insulating material. The passivation layer 80 is provided by being attached to the outer surfaces of the display unit 20 and the backplane 10. A part of the passivation layer 80 is provided by being attached between at least one anode electrical connection structure and the display unit 20, and another part of the passivation layer 80 is provided by being attached between the cathode electrical connection structure 30 and the display unit 20. At least one through hole is formed in the passivation layer 80. At least one through hole is formed between the anode electrical connection structure and the corresponding P-type contact layer, and at least one through hole is formed between the cathode electrical connection structure 30 and the corresponding N-type contact layer.

[0065] Corresponding to the pixel unit 100, according to this embodiment, a manufacturing method of the pixel unit 100 is provided. The manufacturing method of the pixel unit 100 includes preparing a backplane (step S1) and forming a display unit by laminating at least one element layer on the backplane (step S2).

[0066] It includes a P-type contact layer, a pixel layer, and an N-type contact layer in which any element layers are sequentially laminated, and the P-type contact layer is located on one side facing the backplane of the element layers. Specifically, at least one element layer includes a first element layer.

[0067] Furthermore, forming the display unit by laminating at least one element layer on the backplane includes forming a first bonding layer by coating a bonding material on the surface of the backplane and the surface of the P-type contact layer of a previously prepared first compound semiconductor wafer (step S11), and removing the substrate of the first compound semiconductor wafer and thinning the first compound semiconductor wafer to expose the first N-type contact layer as a convex structure (step S12).

[0068] Furthermore, the at least one element layer further includes a second element layer and a third element layer.

[0069] The first compound semiconductor wafer has P-type ohmic contact. It is preferable to use SiO2 for the bonding material so that SiO2-SiO2 bonding is realized. Specifically, the first compound semiconductor wafer having P-type ohmic contact is covered with a silicon oxide film having a flat surface. Here, the surface roughness Ra of the silicon oxide surface is Ra < 7 nm, the film thickness is 10 nm to 10000 nm, and when strengthening the bonding force, a Si layer with a thickness of 1 to 15 nm may be coated on the surface.

[0070] After completing the first element layer, step S2 further includes forming the display unit by laminating the second element layer and the third element layer on one surface of the first element layer separated from the backplane. Since the lamination method of the second element layer and the third element layer is the same as that of the first element layer, these descriptions are omitted.

[0071] As described above, the first element layer uses a first compound semiconductor wafer (red light epitaxy), the second element layer uses a second compound semiconductor wafer (green light epitaxy), and the third element layer uses a third compound semiconductor wafer (blue light epitaxy).

[0072] The compound of the first compound semiconductor wafer is an AlGaInP red light system, and it is preferable to use N-GaAs as the base. These structures are shown in Table 1.

Table 1

[0073] The compounds of the second compound semiconductor wafer and the third compound semiconductor wafer are of the InGaN system, and it is preferable to use Si and GaN for the bases, respectively. These structures are shown in Tables 2 and 3. [Table 2] [Table 3]

[0074] The manufacturing method of the pixel unit 100 further includes forming a cathode electrical connection channel and at least one anode electrical connection channel by etching one surface of the display unit spaced apart from the backplane (step S3).

[0075] Step S3 includes initially etching to an initial depth by pattern dry etching one surface of the display unit spaced apart from the backplane (step S31); etching to a depth by pattern wet etching the display unit after the initial depth etching to expose the backplane and form at least one anode electrical connection channel, and to expose the N-type contact layer and form a cathode electrical connection channel (step S32); and etching to a depth by pattern wet etching the display unit after the initial depth etching to expose the backplane and form a cathode electrical connection channel and at least one anode electrical connection channel (step S33).

[0076] As described above, after step S31 is performed, one of step S32 and step S33 is executed.

[0077] When it is used in the manufacture of a microdisplay and no cathode is provided on the backplane, step S32 is executed. When it is used in the manufacture of an individual element, a cathode pad is provided on the backplane, step S33 is executed, and the cathode electrical connection channel extends to the backplane so that the cathode electrical connection structure of the subsequent structure and the cathode pad are easily connected.

[0078] The manufacturing method of the pixel unit 100 further includes forming a cathode electrical connection structure and at least one anode electrical connection structure by filling a metal into the cathode electrical connection channel and at least one anode electrical connection channel (step S4).

[0079] The cathode electrical connection structure is electrically connected to the N-type contact layer of any of the element layers, and any anode electrical connection structure is electrically connected to the P-type contact layer of the corresponding element layer.

[0080] Specifically, step S4 further includes forming a passivation layer on the outer surfaces of the display unit and the backplane, and on the inner walls of the cathode electrical connection channel and at least one anode electrical connection channel, and forming through holes located between any anode electrical connection structure and the corresponding P-type contact layer, and between the cathode electrical connection structure and the corresponding N-type contact layer by patterning etching (step S41). That is, corresponding to step S33, when extending the cathode electrical connection channel to the backplane, through holes are formed in the passivation layer on the surface of the backplane corresponding to the cathode electrical connection channel.

[0081] Step S4 further includes forming a cathode electrical connection structure and at least one anode electrical connection structure by filling a metal into the cathode electrical connection channel and at least one anode electrical connection channel by sputtering, electroplating, chemical plating or evaporation (step S42).

[0082] From the above, according to this embodiment, a pixel unit, a method for manufacturing the same, a microdisplay, and an individual element are provided. The pixel unit includes a backplane, a display unit, a cathode electrical connection structure, and at least one anode electrical connection structure. The display unit is provided on the backplane. One surface of the cathode electrical connection structure and at least one anode electrical connection structure, which is spaced apart from the backplane, is provided on the display unit so as to be embedded. The display unit includes at least one element layer including a P-type contact layer, a pixel layer, and an N-type contact layer that are sequentially stacked. The P-type contact layer is located on one side of the element layer facing the backplane. Any of the anode electrical connection structures and the P-type contact layer of the corresponding element layer are electrically connected. The cathode electrical connection structure and the N-type contact layer of any of the element layers are electrically connected. In the pixel unit according to this embodiment, by stacking at least two layers of element layers on the backplane, color display can be realized. Therefore, compared with a pixel structure arranged and integrated in the horizontal direction, the space occupied by the pixel unit according to this embodiment in the horizontal direction is small, and ultra-high-density color Micro-LED display can be realized. Thereby, a smaller display size at the same resolution or a higher resolution at the same display size can be realized. In the present invention, a plurality of element layers stacked along the stacking direction share the same cathode electrical connection structure, so that the ratio of the area occupied by the light-emitting region can be increased, and thus the influence of the dimensional effect can be reduced.

[0083] In addition, the first anode electrical connection structure includes a first partial structure and a second partial structure connected in sequence. The end face area of the second partial structure is larger than that of the first partial structure. A first flange is formed at the connection location between the second partial structure and the first partial structure. The image unit further includes a passivation layer, a part of which is closely provided on the outer surfaces of the display unit and the backplane, a part of which is closely provided between at least one anode electrical connection structure and the display unit, and a part of which is closely provided between the cathode electrical connection structure and the display unit. The anode electrode connection structure according to the present invention can realize the electrical connection between the anode electrical connection structure and the P-type contact layer, or the electrical connection between the cathode electrical connection structure and the N-type contact layer by forming a flange structure due to the change in diameter, simplify the structure, and reduce the difficulty of the manufacturing method.

[0084] According to the present invention, there is provided a method for manufacturing a pixel unit, including preparing a backplane, forming a display unit by laminating at least one element layer on the backplane, where any element layer includes a P-type contact layer, a pixel layer, and an N-type contact layer laminated in sequence, the P-type contact layer is located on one side facing the backplane of the element layer, etching one side surface of the display unit away from the backplane to form a cathode electrical connection channel and at least one anode electrical connection channel, and filling the cathode electrical connection channel and at least one anode electrical connection channel with metal to form a cathode electrical connection structure and at least one anode electrical connection structure, where the cathode electrical connection structure is electrically connected to the N-type contact layer of any element layer, and any anode electrical connection structure is electrically connected to the P-type contact layer of the corresponding element layer. The manufacturing method of the pixel unit according to the present invention uses a method of laminating first and then patterning, so it can eliminate the extremely high cost of alignment bonding by semiconductor processes, avoid the deviation of positioning accuracy, realize the lamination of pixels with smaller dimensions in the process, reduce the difficulty of the process, and save the process cost.

[0085] This embodiment has the following excellent effects compared with the prior art.

[0086] Example 2 Based on Example 1, this embodiment further provides a microdisplay 200.

[0087] As shown in FIGS. 2 and 6, the microdisplay 200 includes a driving backplane 210 including a driving circuit and an input / output interface 211, a display area 220 provided on the driving backplane 210, the display area 220 including at least two display units 20 arranged in an array, and a peripheral common cathode 230 provided along the circumferential direction of the display area 220 and connected to the cathode electrical connection structure of any display unit 20.

[0088] The microdisplay 200 further includes an insulating layer 240 provided on the surface of the display area 220.

[0089] The microdisplay 200 further includes a transparent conductive layer 250 provided on the outer surface of the insulating layer 240. At least one blank is formed in the insulating layer 240. The cathode electrical connection structure 30 is connected to the transparent conductive layer 250 through the blank of the insulating layer 240. The transparent conductive layer 250 is connected to the peripheral common cathode 230 to realize the connection between each pixel unit and the cathode electrode.

[0090] According to the microdisplay 200 according to this embodiment, in addition to the technical effects of the pixel unit 100 according to Example 1, by providing the transparent conductive layer, the structure of the cathode electrode can be realized, the etching step of the pixel unit can be simplified, and the influence of etching on the element layer can be avoided, effectively improving the yield of the pixel unit and the microdisplay.

[0091] Example 3 As shown in FIGS. 3 to 5, according to this embodiment based on Embodiment 1, an individual element 300 is provided. The individual element 300 includes an individual element backplane 310 and an element body 320 provided on the individual element backplane 310, where the element body 320 includes at least two display units 20 according to Embodiment 1 arranged in an array, and at least two pads including a cathode pad 330 and at least one anode pad. At least a part of any anode pad and at least a part of the cathode pad 330 are provided on the individual element backplane 310 so as to be embedded. Any anode electrical connection structure is connected to the corresponding anode pad, and the cathode electrical connection structure 30 is connected to the corresponding cathode pad 330.

[0092] Specifically, at least one anode pad includes a first anode pad 340 connected to the first element layer 40, a second anode pad 350 connected to the second element layer 50, and a third anode pad 360 connected to the third element layer 60.

[0093] In a preferred embodiment, the element body 320 and the individual element backplane 310 are provided separately, and at least two pads and the individual element backplane 310 are provided separately. The passivation layer 80 preferably includes a fixing portion 81 connected to the individual element backplane 310. The fixing portion 81 is used for connecting the element body 320 and the individual element backplane 310. Specifically, a passivation layer 370 is provided in advance between the individual element backplane 310 and the element body 320 and between the individual element backplane 310 and at least one pad, and a method of removing the passivation layer 370 is realized.

[0094] Corresponding to the individual element, according to this embodiment, a manufacturing method of the individual element is provided. The manufacturing method of the individual element includes preparing an individual element backplane (step S10).

[0095] Specifically, step S10 includes forming four cavities by etching a pre-prepared individual element backplane (step S101); forming a sacrificial layer by coating the individual element backplane with the formed four cavities with a sacrificial layer, using a silicon oxynitride film as the sacrificial layer, and performing coating, thermal oxidation, wet oxidation, etc. of the silicon oxynitride film on the surface of the individual element backplane (step S102); and forming at least four pads on one side of the individual element backplane coated with the sacrificial layer, providing the pads in corresponding cavities such that a part of each pad is embedded, and the at least four pads including one cathode pad and at least three anode pads (step S103).

[0096] The pads according to this embodiment use metal pads. The metal pads may be one or more alloys or laminations of gold, titanium, tungsten, aluminum, and platinum. This manufacturing method includes evaporation, sputtering, electroplating, chemical plating, etc. The pads may be solid or hollow.

[0097] The manufacturing method of the individual element further includes forming a display unit by laminating at least one element layer on the individual element backplane and constituting a cathode electrical connection structure and at least one anode electrical connection structure (step S20).

[0098] Specifically, step S20 includes: performing initial-depth etching on one surface of the display unit that is separated from the individual element backplane by patterned dry etching (step S201); performing depth etching on the display unit that has undergone the initial-depth etching by patterned wet etching to expose the individual element backplane and form a cathode electrical connection channel and at least one anode electrical connection channel (step S202); forming a passivation layer on the outer surfaces of the element body and the individual element backplane, and on the inner walls of the cathode electrical connection channel and at least one anode electrical connection channel, forming at least one through hole by patterned etching, and providing at least one through hole between any anode electrical connection structure and the corresponding P-type contact layer, and providing at least one through hole between any cathode electrical connection structure and the corresponding individual element backplane (step S203).

[0099] The passivation layer covers a part of the individual element backplane. The passivation layer forms a fixing portion at the connection location between the element body and the individual element backplane. The fixing portion realizes the connection between the element body and the individual element backplane.

[0100] The method for manufacturing the individual element further includes obtaining the individual element by removing the sacrificial layer (step S30).

[0101] Specifically, by etching the sacrificial layer on one surface of the individual element backplane that is not coated with the passivation layer, at least four pads are separated from the individual element backplane. The etching rate ratio between the sacrificial layer and the individual element backplane is greater than 10:1, and the etching rate ratio between the sacrificial layer and the passivation layer is greater than 10:1. The gap between the etched individual element backplane and the element body is 100 nm to 1000 nm, preferably 300 nm to 500 nm.

[0102] From the above, in addition to the technical effects of the pixel unit according to the first embodiment, the individual element according to this embodiment is connected to an external circuit via at least two pads. When packaging and electrically connecting the individual element to the target backplane, eutectic or other metal welding can be avoided, so that the performance impact on the individual element itself can be avoided and the manufacturing process can be simplified. Further, the element body and the individual element backplane according to this embodiment are provided separately, and the four pads and the individual element backplane are provided separately. The pixel-level individual element further includes an isolation support structure that covers a part of the element body and the individual element backplane. By providing the isolation support structure, the pixel-level individual element can achieve the stability of the structure in which the element body and the individual element backplane are provided and the convenience during use. Moreover, in such a structure, the individual element backplane can be reused, effectively reducing costs.

[0103] All the selectable technical means described above may be arbitrarily combined to form selectable embodiments of the present application. That is, arbitrarily combining a plurality of embodiments so as to meet the requirements for different application scenarios is within the protection scope of the present application, which will not be described in detail here.

[0104] It should be noted that the above is only a preferred embodiment of the present application and is not used to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the scope of the spirit and principle of the present application are all included in the protection scope of the present application.

Explanation of Reference Numerals

[0105] 100 Pixel unit 10 Driving backplane 20 Display unit 30 Cathode electrical connection structure 31 Third partial structure 32 Fourth partial structure 33 Fifth partial structure 40 First element layer 41 First bonding layer 42 First P-type contact layer 43 First pixel layer 44 First N-type contact layer 50 Second element layer 51 Second junction layer 511 Functional layer 512 Second junction layer body 52 Second P-type contact layer 53 Second pixel layer 54 Second N-type contact layer 60 Third element layer 61 Third junction layer 62 Third P-type contact layer 63 Third pixel layer 64 Third N-type contact layer 71 First anode electrical connection structure 711 First partial structure 712 Second partial structure 713 First flange 72 Second anode electrical connection structure 721 Second flange 73 Third anode electrical connection structure 731 Third flange 80 Passivation layer 81 Fixing part 200 Microdisplay 210 Driving backplane 211 Input / output interface 220 Display area 230 Surrounding common cathode 240 Insulating layer 250 Transparent conductive layer 300 Individual element 310 Individual element backplane 320 Element body 330 Cathode pad 340 First anode pad 350 Second anode pad 360 Third anode pad

Claims

1. A pixel unit, comprising a backplane, a display unit, a cathode electrical connection structure, and at least one anode electrical connection structure, wherein the display unit is provided on the backplane, one surface of the cathode electrical connection structure and at least one anode electrical connection structure, which is spaced from the backplane, is provided on the display unit in an embedded manner, the display unit includes at least one element layer including a P-type contact layer, a pixel layer, and an N-type contact layer that are sequentially laminated, the P-type contact layer is located on one side of the element layer facing the backplane, any one of the anode electrical connection structures is electrically connected to the P-type contact layer of the corresponding element layer, the cathode electrical connection structure is electrically connected to the N-type contact layer of any one of the element layers, characterized in that.

2. Any one of the anode electrical connection structures is connected to the backplane, at least one of the anode electrical connection structures includes a first anode electrical connection structure including a first partial structure and a second partial structure that are sequentially connected, at least one of the element layers includes a first element layer including a first bonding layer, a first P-type contact layer, a first pixel layer, and a first N-type contact layer that are sequentially laminated, the first P-type contact layer is located on one side of the first element layer close to the backplane, the first partial structure is provided on the first bonding layer and the first P-type contact layer in an embedded manner, the second partial structure is provided on the first pixel layer such that a part thereof is embedded and is electrically connected to the first P-type contact layer, characterized in that the pixel unit according to claim 1.

3. The end face area of the second partial structure is larger than the end face area of the first partial structure, a first flange is formed at the connection position between the second partial structure and the first partial structure, the first flange is connected to the first P-type contact layer, characterized in that the pixel unit according to claim 2.

4. At least one of the anode electrical connection structures further includes a second anode electrical connection structure, the display unit further includes a second element layer laminated on one surface of the first element layer spaced from the backplane, the second element layer includes a second bonding layer, a second P-type contact layer, a second pixel layer, and a second N-type contact layer that are sequentially laminated, the second bonding layer is connected to the first pixel layer, The second anode electrical connection structure includes a second flange connected to the second P-type contact layer. The pixel unit according to claim 2, characterized in that.

5. The second N-type contact layer is provided directly above the first N-type contact layer. The pixel unit according to claim 4, characterized in that.

6. The first N-type contact layer has a convex structure and is provided in the second bonding layer so as to be embedded. The pixel unit according to claim 4, characterized in that.

7. The cathode electrical connection structure includes a third partial structure provided in the second element layer so as to be embedded and having one end connected to the first N-type contact layer. The pixel unit according to claim 6, characterized in that.

8. The cathode electrical connection structure further includes a fourth partial structure having one end connected to the backplane and the other end passing through the first element layer and connected to the third partial structure. The pixel unit according to claim 7, characterized in that.

9. The second bonding layer includes a second bonding layer main body and a functional layer provided between the second bonding layer main body and the first pixel layer. The pixel unit according to claim 4, characterized in that.

10. At least one of the anode electrical connection structures further includes a third anode electrical connection structure. The display unit includes a third element layer laminated on one surface of the second element layer separated from the first element layer. The third element layer includes a third bonding layer, a third P-type contact layer, a third pixel layer, and a third N-type contact layer laminated in sequence. The third bonding layer is connected to the second pixel layer. The anode electrical connection structure includes a third flange connected to the third P-type contact layer. The pixel unit according to claim 7, characterized in that.

11. The cathode electrical connection structure further includes a fifth partial structure connected to the third partial structure and provided in the third element layer so as to be embedded. By making the end face area of the fifth partial structure larger than the end face area of the third partial structure, a fourth flange is formed at the connection portion between the fifth partial structure and the third partial structure. The fourth flange is connected to the second N-type contact layer. The pixel unit according to claim 10, characterized in that.

12. The second N-type contact layer has a convex structure and is provided in the third bonding layer so as to be embedded. The pixel unit according to claim 11, characterized in that...

13. Both the second bonding layer and the third bonding layer are made of a transparent material. The pixel unit according to claim 12, characterized in that...

14. Further comprising a passivation layer, a part of which is provided in close contact with the outer surfaces of the display unit and the backplane, a part of which is provided in close contact between at least one of the anode electrical connection structures and the display unit, and a part of which is provided in close contact between the cathode electrical connection structure and the display unit. The pixel unit according to any one of claims 1 to 13, characterized in that...

15. At least one through hole is formed in the passivation layer between any of the anode electrical connection structures and the corresponding P-type contact layer, and between the cathode electrical connection structure and the corresponding N-type contact layer. The pixel unit according to claim 14, characterized in that...

16. The passivation layer is made of a transparent material. The pixel unit according to claim 14, characterized in that...

17. The first pixel layer is an AlGaInP or InGaN red light compound epitaxy. The second pixel layer is an InGaN green light compound epitaxy. The third pixel layer is an InGaN blue light compound epitaxy. The pixel unit according to any one of claims ​ ​ ​ ​ ​ A method for manufacturing a pixel unit, characterized in that...

19. At least one of the element layers includes a first element layer. Forming a display unit by laminating at least one element layer on the backplane includes: Forming a first bonding layer by coating a bonding material on the surface of the backplane and the surface of the P-type contact layer of a pre-prepared first compound semiconductor wafer. Removing the substrate of the first compound semiconductor wafer and thinning the first compound semiconductor wafer to expose a first N-type contact layer as a convex structure. A method for manufacturing a pixel unit according to claim 18, characterized in that...

20. At least one of the element layers further includes a second element layer and a third element layer. After completing the first element layer, forming a display unit by laminating at least one element layer on the backplane further includes: Forming the display unit by laminating the second element layer and the third element layer on a surface of the first element layer on one side separated from the backplane. A method for manufacturing a pixel unit according to claim 19, characterized in that...

21. Constituting a cathode electrical connection channel and at least one anode electrical connection channel by etching a surface of the display unit on one side separated from the backplane includes: Performing initial depth etching on the surface of the display unit on one side separated from the backplane by patterned dry etching. Performing depth etching on the display unit after the initial depth etching by patterned wet etching to expose the backplane to form at least one anode electrical connection channel and to expose the N-type contact layer to form the cathode electrical connection channel. A method for manufacturing a pixel unit according to claim 18, characterized in that...

22. Constituting the cathode electrical connection channel and at least one of the anode electrical connection channels by etching a surface of the display unit on one side separated from the backplane includes: Performing initial depth etching on the surface of the display unit on one side separated from the backplane by patterned dry etching. Performing deep etching on the display unit that has undergone initial deep etching by means of pattern wet etching to expose the backplane and form at least one anode electrical connection channel and the cathode electrical connection channel. A method for manufacturing a pixel unit according to claim 18, characterized by the above.

23. Forming the cathode electrical connection structure and at least one of the anode electrical connection structures by filling the cathode electrical connection channel and at least one of the anode electrical connection channels with metal. Forming a passivation layer on the outer surfaces of the display unit and the backplane, and on the inner walls of the cathode electrical connection channel and at least one of the anode electrical connection channels, and forming via holes located between any of the anode electrical connection structures and the corresponding P-type contact layer, and between the cathode electrical connection structure and the corresponding N-type contact layer by means of pattern etching. Including filling the cathode electrical connection channel and at least one of the anode electrical connection channels with metal by means of sputtering, electroplating, chemical plating or evaporation to constitute the cathode electrical connection structure and at least one of the anode electrical connection structures. A method for manufacturing a pixel unit according to claim 21 or 22, characterized by the above.

24. A driving backplane including a driving circuit and an input / output interface. A display area provided in the driving backplane, the display area including at least two pixel units according to any one of claims 1 to 7, 9 to 17, arranged in an array. Including a peripheral common cathode provided along the circumferential direction of the display area and connected to the cathode electrical connection structure of any of the display units. A microdisplay, characterized by the above.

25. A driving circuit is integrated on the backplane. The driving circuit corresponding to any of the pixel units further includes at least one anode connected to any of the anode electrical connection structures. A microdisplay according to claim 24, characterized by the above.

26. Further including an insulating layer and a transparent conductive layer provided in close contact with the display area in order from the inside to the outside. The transparent conductive layer is connected to the peripheral common cathode. At least one blank is formed in the insulating layer. The cathode electrical connection structure is connected to the transparent conductive layer by the blank of the insulating layer. The microdisplay according to claim 25, characterized in that.

27. An individual element backplane, An element body provided on the individual element backplane, the element body including at least two pixel units according to any one of claims 1 to 17 arranged in an array, At least two pads including a cathode pad and at least one anode pad, At least a part of any of the anode pads and at least a part of the cathode pad are provided on the individual element backplane so as to be embedded, Any of the anode electrical connection structures is connected to the corresponding anode pad, and the cathode electrical connection structure is connected to the corresponding cathode pad. An individual element, characterized in that.

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