Micro-display device and preparation method

Abstract

The invention relates to a micro display device and a preparation method. The micro-display device comprises a driving backboard, a first pixel layer and a second pixel layer, the mother pixel comprises a plurality of sub-pixels, the top end of each sub-pixel is electrically connected to the corresponding second-type electrode contact through a top conductive layer, and the bottom ends of the plurality of sub-pixels are interconnected through a bottom conductive layer to form a bottom copolar structure; a gap region is formed between every two adjacent sub-pixels in the first pixel layer, and a common-pole conductive part penetrates through the gap region; and at least part of light emitted by any one of the two adjacent sub-pixels forming the gap region is emitted from the periphery of the upper sub-pixel electrically connected with the common-pole conductive piece in the gap region. The invention further discloses a preparation method. The light efficiency and the reliability of the micro display device can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a micro display device and a preparation method thereof. BACKGROUND

[0002] Micro display devices have small size, high resolution, high brightness and other characteristics, and can be applied to AR / VR devices, vehicle-mounted displays, medical detection and smart wear, and many other fields. Micro display devices such as Micro-LED and Micro-OLED have been widely developed in recent years. In particular, Micro-LED display technology has high efficiency, low power consumption, high integration and high stability, and is considered to be one of the most promising next-generation new display and light-emitting devices. In the field of micro display, in order to further ensure the pixel size and pixel density, there is a need for multi-color stacked integration when performing color display. LED devices in a multi-layer stacked form generally have a driving backboard (with a driving circuit) and a multi-layer structure above the driving backboard. Pixels are arranged in each layer structure, and each layer of pixels needs to be electrically connected to the driving backboard. The overall structure is complex, there is a large loss of light emitting area for each pixel, the best light distribution effect cannot be achieved, and the overall device has higher power consumption, which is not conducive to ensuring the reliability and stability of the LED display device. SUMMARY

[0003] Therefore, the technical problem to be solved by the present application is to improve the light efficiency and reliability of the micro display device in the prior art.

[0004] To solve the above technical problems, the present application provides a micro display device, comprising,

[0005] a driving backboard, wherein the driving backboard is provided with second electrode contacts;

[0006] a first pixel layer, wherein the first pixel layer is stacked above the driving backboard;

[0007] a second pixel layer, wherein the second pixel layer is stacked above the first pixel layer;

[0008] a parent pixel, wherein the parent pixel comprises a plurality of sub-pixels, part of the plurality of sub-pixels are located in the first pixel layer, and the remaining sub-pixels are located in the second pixel layer;

[0009] the top end of each sub-pixel in the plurality of sub-pixels is electrically connected to the corresponding second electrode contact through a top conductive layer, and the bottom end of the plurality of sub-pixels is interconnected through a bottom conductive layer to form a bottom common electrode structure;

[0010] The gap region is formed between two adjacent sub-pixels in the first layer of pixel layer, and the gap region is internally penetrated by a common electrode conductor. The bottom conductive layer of the bottom end of any one of the two adjacent sub-pixels forming the gap region is electrically connected to the bottom conductive layer of the bottom end of the other sub-pixel forming the gap region. The light emitted by any one of the two adjacent sub-pixels forming the gap region is at least partially emitted through the periphery of the upper sub-pixel electrically connected by the common electrode conductor in the gap region.

[0011] In an embodiment of the present application, the upper side of the first layer of pixel layer is further provided with a color conversion layer, and the color conversion layer is located on the light emitting path of the corresponding sub-pixel in the first layer of pixel layer.

[0012] In an embodiment of the present application, the color conversion layer is arranged on the light emitting path of one of the two adjacent sub-pixels forming the gap region, and the color conversion layer is not arranged on the light emitting path of the other sub-pixel.

[0013] In an embodiment of the present application, the projection area of the upper sub-pixel electrically connected by the common electrode conductor in the gap region on the driving backplane is at least partially located in the projection area of the gap region on the driving backplane.

[0014] In an embodiment of the present application, the projection area of the upper sub-pixel electrically connected by the common electrode conductor in the gap region on the driving backplane is completely located in the projection area of the gap region on the driving backplane.

[0015] In an embodiment of the present application, the micro display device further comprises a first type of electrode contact, and the polarity of the first type of electrode contact is opposite to that of the second type of electrode contact. The bottom conductive layer of the bottom end of any one of the two adjacent sub-pixels forming the gap region is electrically connected to at least one first type of electrode contact.

[0016] In an embodiment of the present application, the bottom ends of the two adjacent sub-pixels forming the gap region share a bottom conductive layer. The bottom surface of the shared bottom conductive layer is electrically connected to the corresponding first type of electrode contact, and the top surface of the shared bottom conductive layer is electrically connected to the common electrode conductor in the gap region.

[0017] In an embodiment of the present application, a bottom ohmic contact layer is further arranged between the bottom ends of the two adjacent sub-pixels forming the gap region and the shared bottom conductive layer, and the bottom ohmic contact layer is penetrated by the common electrode conductor in the gap region.

[0018] In an embodiment of the present application, the bottom end of the common electrode conductor inside the gap region is in contact with the corresponding first electrode contact to achieve electrical connection, and the bottom conductive layer of the bottom end of the adjacent two sub-pixels of the gap region is electrically connected to the first electrode contact to which the bottom end of the common electrode conductor is electrically connected.

[0019] In an embodiment of the present application, the top conductive layer of each sub-pixel is electrically connected to the corresponding second electrode contact through a non-common electrode conductor.

[0020] In an embodiment of the present application, the bottom end of the non-common electrode conductor is in direct contact with the corresponding second electrode contact.

[0021] In an embodiment of the present application, the gap region comprises an annular region, the common electrode conductor is arranged in the annular region, and each of the side walls of the adjacent two sub-pixels of the gap region has a groove part, and the annular region is enclosed between the groove parts of the adjacent two sub-pixels.

[0022] In an embodiment of the present application, the bottom conductive layer adopts a metal bonding layer.

[0023] In an embodiment of the present application, the periphery of at least one sub-pixel is surrounded by a first peripheral metal fence, and the first peripheral metal fence and the side wall of the surrounded sub-pixel are insulated and separated by a first insulating layer.

[0024] In an embodiment of the present application, the bottom ends of the adjacent two sub-pixels of the gap region share one bottom conductive layer, the upper part of the shared bottom conductive layer forms a first peripheral metal fence, and the adjacent two sub-pixels of the gap region are surrounded by one first peripheral metal fence.

[0025] In an embodiment of the present application, a first insulating filling region is arranged inside the gap region, and the common electrode conductor inside the gap region directly passes through the first insulating filling region.

[0026] In an embodiment of the present application, a display region is divided on the driving back plate, all the parent pixels constitute a pixel array, the projection of the pixel array on the driving back plate is located inside the display region, a first electrode contact is arranged inside the display region, and / or the first electrode contact is arranged outside the display region.

[0027] In one embodiment of the present application, the top ends of the sub-pixels in the parent pixel located in the first layer of pixel layer and the second layer of pixel layer are each provided with the top conductive layer, and the top conductive layer in the first layer of pixel layer is located above the electrically connected sub-pixels, and the top conductive layer in the second layer of pixel layer is located above the electrically connected sub-pixels.

[0028] In one embodiment of the present application, at least one of the top conductive layers is electrically connected with a metal reinforcing member.

[0029] In one embodiment of the present application, the top ends of the sub-pixels in the parent pixel located in the first layer of pixel layer and the second layer of pixel layer are each provided with the top conductive layer, and the top conductive layer in the first layer of pixel layer is completely located above the electrically connected sub-pixels, and the top conductive layer in the second layer of pixel layer is completely located above the electrically connected sub-pixels.

[0030] In one embodiment of the present application, the light-emitting colors of at least two of the sub-pixels are different, one of the sub-pixels is located in the first layer of pixel layer, and the other of the sub-pixels is located in the second layer of pixel layer.

[0031] The present application also discloses a preparation method of a micro display device, comprising,

[0032] providing a driving back plate, the driving back plate being provided with second type electrode contacts;

[0033] stacking two layers of pixel layers on the driving back plate from bottom to top, each layer of pixel layer being etched to obtain a sub-pixel, the two layers of pixel layers being a first layer of pixel layer and a second layer of pixel layer, the first layer of pixel layer and the second layer of pixel layer each being a compound semiconductor layer, so that each parent pixel includes a plurality of sub-pixels, part of the sub-pixels being located in the first layer of pixel layer, and the rest of the sub-pixels being located in the second layer of pixel layer;

[0034] so that the top ends of each of the sub-pixels in the parent pixel are each electrically connected to the corresponding second type electrode contact through a top conductive layer, and the bottom ends of the plurality of sub-pixels are interconnected through a bottom conductive layer to form a bottom common electrode structure;

[0035] The gap area is internally passed through by a common electrode conductor, the bottom conductive layer of the bottom end of the adjacent two sub-pixels forming the gap area is conductively interconnected, the bottom end of the common electrode conductor in the gap area is electrically connected to the bottom conductive layer of the bottom end of any one of the adjacent two sub-pixels forming the gap area, and the top end is electrically connected to the bottom conductive layer of another sub-pixel in the second layer of pixel layer; the light emitted by any one of the adjacent two sub-pixels forming the gap area is at least partially emitted through the periphery of the upper sub-pixel to which the common electrode conductor in the gap area is electrically connected.

[0036] The above technical solutions of the present application have the following advantages compared with the prior art:

[0037] The micro display device can effectively reduce the shielding of the lower sub-pixel light emitting surface, ensure the effective light emitting area of the lower sub-pixel, reduce energy waste, improve the light distribution effect, realize color conversion of the sub-pixel light emitting color through the color conversion layer, and improve the light efficiency and reliability of the display device. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the drawings.

[0039] Figure 1 is a structural schematic diagram of a first micro display device of the present application;

[0040] Figure 2 is a structural schematic diagram of a second micro display device of the present application; Figure 1 is a schematic diagram (top view) of the arrangement of each sub-pixel in the present application;

[0041] Figure 3 is a schematic diagram (top view) of the arrangement of the top electrode layer of each sub-pixel in the present application; Figure 1

[0042] Figure 4 is a schematic diagram of the bonding of the driving back plate and the first layer of pixel layer in the present application;

[0043] Figure 5 is a flow chart of the preparation of the micro display device shown in the present application; Figure 1

[0044] Figure 6 is a structural schematic diagram of a second micro display device of the present application;

[0045] Figure 7 is a schematic diagram (top view) of the distribution of the display area in the present application;

[0046] Figure 8 ​​is a schematic view (top view) of the peripheral electrode contact area and the interface connection in the present application;

[0047] Figure 9 is a schematic view of the structure of the third micro display device in the present application;

[0048] Description of the drawings:

[0049] 10, drive backplane; 101, first type of electrode contact; 102, second type of electrode contact; 103, display area; 104, peripheral electrode contact area; 105, interface;

[0050] 20, first layer of pixel layer;

[0051] 30, second layer of pixel layer;

[0052] 40, color conversion layer;

[0053] 50, sub-pixel;

[0054] 60, top conductive layer;

[0055] 70, bottom conductive layer;

[0056] 80, non-epipolar conductive member;

[0057] 90, epipolar conductive member;

[0058] 100, first insulating filling area;

[0059] 140, first peripheral metal fence; 150, first insulating layer; 160, second insulating layer; 180, bottom ohmic contact layer; 190, metal reinforcing member; 230, etching stop layer; 300, gap area; 3001, annular area; 3002, recessed portion; DETAILED DESCRIPTION

[0060] The present application will be further described below with reference to the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it. It is obvious that the described embodiments are only a part of the embodiments of the present disclosure, not all. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present disclosure and its application or use.

[0061] In the description of the present application, it needs to be understood that the terms "vertical", "upper", "lower", "top", "side", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can be explicitly or implicitly included one or more. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0062] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0063] The LED device in the conventional technology in the form of multi-layer stacking has a complex overall structure, a large loss of light emitting area of each pixel, and cannot achieve the best light distribution effect, and the overall device has higher power consumption, which is not conducive to ensuring the reliability and stability of the LED display device. In view of this, the present application provides a micro display device to improve the above problems, so as to better ensure the photoelectric performance and reliability of the LED display device.

[0064] It should be noted that the compound semiconductor layer in the present application refers to a layer structure with a certain thickness prepared from a compound semiconductor material. Compound semiconductors generally refer to compounds formed by two or more elements, including crystalline inorganic compounds (such as III-V, II-VI compound semiconductors) and oxide semiconductors. The compound semiconductors involved in the present application are mainly light emitting diode epitaxial materials, such as InGaN ternary material system or AlGaInP quaternary material system, etc., which can cover the full wavelength range from ultraviolet, visible light and infrared, and the substrate material can be GaN, Si, SiC, sapphire, GaAs, InP, etc.

[0065] For example, in the field of Micro-LED, some compound semiconductor materials involved in the present application are shown in Table 1. In some practical applications, the film layer of the compound semiconductor is more complex, or the material is used in a cross-use manner. The typical compound semiconductor mainly includes P-type semiconductor material, N-type semiconductor material, and MQW active quantum well sandwiched between the two and other functional layers (barrier layer, confinement layer, waveguide layer, buffer layer, etc.):

[0066] Table 1: Compound semiconductor film layer material table

[0067]

[0068] The structure of the micro display device of the present application will be further described below in combination with the following specific embodiments.

[0069] Embodiment 1

[0070] Referring to Figure 1 The present embodiment discloses a multi-layer stacked micro display device, which includes at least one parent pixel, each parent pixel having a plurality (two or more) of sub-pixels. The structure of the above micro display device will be specifically described below by taking a parent pixel with two sub-pixels as an example. The structure shown in the drawings only shows the case of one parent pixel, and the structure inside each parent pixel is basically the same when there are multiple parent pixels.

[0071] The micro display device in the present application has Z, X and Y directions, and any two of the three directions are perpendicular to each other. The Z direction is the stacking direction of the sub-pixels of each layer, that is, the up-down direction, and can also be understood as the direction away from / approaching the driving backboard. The "height" or "up / down" or "top / bottom" is along the Z direction.

[0072] In the present application, the "bottom end of the sub-pixel" refers to the end of the sub-pixel close to the driving backboard, and the "top end of the sub-pixel" refers to the end of the sub-pixel away from (far from) the driving backboard.

[0073] It should be noted that the cross-sectional view of each layer in the XZ plane in the drawings of the present application can be a schematic view after cutting a single section, or a schematic view after cutting a plurality of sections in combination, so as to show the connection of different electrode contacts.

[0074] The LED display device in the present embodiment includes a driving backboard 10 and a parent pixel, and the parent pixel includes a plurality of sub-pixels 50.

[0075] The driving backboard 10 is an element with a driving circuit, the first electrode contact 101 and the second electrode contact 102 are the lead terminals of the driving circuit, and are used to electrically connect the driving circuit and the sub-pixel 50. The sub-pixel 50 is a light-emitting element. Through the electrical connection between the driving backboard 10 and the sub-pixel 50, the connection between the sub-pixel 50 and the driving circuit is realized, so that the sub-pixel 50 can be driven to emit light. Each sub-pixel 50 can be individually driven to emit light independently.

[0076] The driving backboard 10 includes but is not limited to a CMOS (Complementary Metal Oxide Semiconductor) driving backboard.

[0077] The driving backboard 10 can be provided with the first electrode contact 101 and the second electrode contact 102. The polarities of the first electrode contact 101 and the second electrode contact 102 are opposite, one of which is an anode and the other of which is a cathode. It can be understood that, in order to prevent short circuit, the first electrode contact 101 and the second electrode contact 102 need to be insulated and separated. Through the arrangement of the first electrode contact 101 and the second electrode contact 102, the driving backboard 10 can be electrically connected with the sub-pixel 50, so that the driving backboard 10 can be used to control the light emission of each sub-pixel 50.

[0078] It can be understood that the two ends of the sub-pixel 50 along the Z direction are a bottom end and a top end, respectively. The bottom end and the top end of the sub-pixel 50 are two ends with opposite polarities. The sub-pixel 50 includes a P-type semiconductor layer, an active layer and an N-type semiconductor layer arranged in sequence along the Z direction. The active layer is used to emit light. The top end of the sub-pixel 50 is the end where the N-type semiconductor layer is located (or the end where the P-type semiconductor layer is located-anode), and the bottom end is the end where the P-type semiconductor layer is located (or the end where the N-type semiconductor layer is located-cathode), which need to be connected to electrode contacts with different polarities, respectively.

[0079] Referring to Figure 1 The embodiment discloses a micro display device, which includes a driving backboard 10 and a mother pixel.

[0080] The driving backboard 10 is provided with the second electrode contact 102;

[0081] The driving backboard 10 is provided with the second electrode contact 102;

[0082] The first layer of pixel layers 20 is stacked above the driving backboard 10;

[0083] The second layer of pixel layers 30 is stacked above the first layer of pixel layers 20;

[0084] The parent pixel includes a plurality of sub-pixels 50, part of which are located in the first layer of pixel layer 20, and the rest are located in the second layer of pixel layer 30.

[0085] In the parent pixel: the top end of each of the plurality of sub-pixels 50 is electrically connected to the corresponding second type of electrode contact 102 through the top conductive layer 60, and the bottom end of the plurality of sub-pixels 50 is interconnected through the bottom conductive layer 70 to form a bottom common electrode structure; that is, the bottom conductive layer 70 of each sub-pixel 50 in the bottom common electrode structure is electrically connected together and in conductive communication with each other.

[0086] In addition, a gap area 300 is formed between the two adjacent sub-pixels 50 in the first layer of pixel layer 20, the gap area 300 is internally passed through by the common electrode conductive member 90, the bottom conductive layer 70 of the bottom end of the two adjacent sub-pixels 50 forming the gap area 300 is electrically interconnected, the bottom end of the common electrode conductive member 90 inside the gap area 300 is electrically connected to the bottom conductive layer 70 of the bottom end of any one of the two adjacent sub-pixels 50 forming the gap area 300, and the top end is electrically connected to the bottom conductive layer 70 of the other sub-pixel 50 in the second layer of pixel layer 30; the light emitted by any one of the two adjacent sub-pixels 50 forming the gap area 300 is at least partially emitted through the periphery of the upper sub-pixel 50 to which the common electrode conductive member 90 inside the gap area 300 is electrically connected without being blocked by the upper sub-pixel 50, thereby effectively reducing the blocking of the light emitting surface of the lower sub-pixel, increasing the effective light emitting area of the lower sub-pixel, and facilitating the realization of the best light distribution effect. As Figure 1 As shown, the dashed arrow direction in the figure is the light emitting direction of the first layer of sub-pixels.

[0087] The upper side of the first layer of pixel layer 20 can also be provided with a color conversion layer 40, which is located on the light emitting path of the corresponding sub-pixel 50 in the first layer of pixel layer 20 to realize the conversion of the light emitting color of the sub-pixel.

[0088] The color conversion layer 40 can realize the conversion of the light emitting color, for example, the light emitting color of a sub-pixel 50 is blue, and a color conversion layer is provided on the light emitting path of the blue sub-pixel, so that when the light emitted by the blue sub-pixel is incident on the color conversion layer, the color conversion layer is excited to emit light of another color, for example, the blue light emitted by the blue sub-pixel may present red color after being converted by the color conversion layer.

[0089] Among them, the color conversion layer 40 described above can adopt quantum dot material or fluorescent powder material, so as to be excited by external light to occur color conversion and emit light of a certain color.

[0090] It should be noted that generally shorter wavelength light is used to excite the color conversion layer to emit longer wavelength light, for example, blue light can be used to excite the color conversion layer to finally emit red light.

[0091] The color conversion layer is arranged to realize the conversion of the light-emitting color of some sub-pixels in the bottom layer, so that the display device presents a color display effect, and the structure of the whole device is also simple and convenient for processing.

[0092] For example, refer to Figures 1-2 , Figure 1 may be Figure 2 The rotation cross-sectional view of the structure along A-A; the first layer pixel layer 20 has two sub-pixels 50, and the gap area 300 formed between the two sub-pixels 50, and the second layer pixel layer 30 has one sub-pixel 50. It should be noted that Figure 2 In the first layer pixel layer 20, the sub-pixel 50 is denoted as i1, and the second type of electrode contact 102 connected thereto is denoted as k1. In the second layer pixel layer 30, the sub-pixel 50 is denoted as i2, and the second type of electrode contact 102 connected thereto is denoted as k2.

[0093] It should be noted that Figure 1 In the first layer pixel layer 20, the sub-pixel 50 is denoted as i1, and the second type of electrode contact 102 connected thereto is denoted as k1. In the second layer pixel layer 30, the sub-pixel 50 is denoted as i2, and the second type of electrode contact 102 connected thereto is denoted as k2, and each sub-pixel is electrically connected to the top conductive layer 60. Figure 3 , Figure 3 In the first layer pixel layer 20, the sub-pixel 50 is denoted as i1, and the second type of electrode contact 102 connected thereto is denoted as k1. In the second layer pixel layer 30, the sub-pixel 50 is denoted as i2, and the second type of electrode contact 102 connected thereto is denoted as k2, and each sub-pixel is electrically connected to the top conductive layer 60.

[0094] The above structure is arranged in the gap area 300 between the two independent adjacent sub-pixels 50 in the first layer pixel layer 20, and the common electrode conductive member 90 is arranged in the gap area 300, so that the upper sub-pixel electrically connected to the common electrode conductive member 90 is located above the gap area 300, which can effectively reduce the shielding of the lower sub-pixel light-emitting surface, increase the effective light-emitting area of the lower sub-pixel, and facilitate the realization of the best light distribution effect; at the same time, the problem of light shielding and light absorption of the metal bonding layer to the lower sub-pixel when the metal bonding layer is arranged at the bottom end of the upper sub-pixel is also reduced, thereby reducing the energy waste of the lower sub-pixel and the phenomenon of excessive temperature of the device due to energy loss converted into heat, thereby effectively increasing the light efficiency and reliability of the display device.

[0095] In addition, the sub-pixel distribution structure of the above structure can flexibly adjust the effective light-emitting area of the peripheral sub-pixels of the gap area by adjusting the size of the gap area, so as to make up for the short board of the light intensity of some sub-pixels being too bright or too dark, thereby adjusting the light type of the multi-color stacked device to meet the different needs of XR (extended reality) application;

[0096] As is understood, in this invention, "upper pixel layer" refers to all pixel layers located above the lowermost pixel layer, while "lower pixel layer" is the pixel layer located below the upper pixel layer. Similarly, "upper sub-pixel" refers to all sub-pixels located above the lowermost sub-pixel, while "lower sub-pixel" is the sub-pixel located below the upper sub-pixel.

[0097] Furthermore, the top conductive layer 60 of each sub-pixel is a transparent conductive layer to facilitate light transmission, allowing light emitted from the lower sub-pixel to pass through the top conductive layer 60 and shine upwards.

[0098] For example, the top conductive layer 60 is a transparent conductive layer, which may be one or more combinations of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), Al-doped indium tin oxide, Ag-doped indium tin oxide, and Au-doped indium tin oxide.

[0099] In some implementations, see Figure 1 In the two adjacent sub-pixels 50 forming the gap region 300, a color conversion layer 40 is set on the light-emitting path of one sub-pixel 50, while no color conversion layer is set on the light-emitting path of the other sub-pixel 50, so that the final light-emitting colors of the two are different, realizing multi-color configuration, and also making the overall structure more compact, which is conducive to improving pixel density.

[0100] For example, a subpixel that emits blue light is called a blue subpixel. A blue subpixel is set in the first pixel layer 20. A gap area 300 is formed between two adjacent blue subpixels. A red light conversion layer covers the top of a blue subpixel. The blue light emitted by the subpixel is converted into red light after being converted by the red light conversion layer. The other blue subpixel does not have a color conversion layer on top and still emits blue light.

[0101] Understandably, in this embodiment, the two adjacent sub-pixels 50 forming the gap region 300 and the upper sub-pixel 50 electrically connected to the common conductive element 90 inside the gap region 300 are arranged on opposite axes.

[0102] The shape of each sub-pixel 50 is not limited; it can be a circle, ellipse, polygon (triangle, trapezoid, rectangle, etc.) or other shapes.

[0103] In some embodiments, the common electrode conductive element 90 may be made of metals such as aluminum (Al), copper (Cu), and tungsten (W) and their corresponding adhesive or barrier layers, such as titanium (Ti), titanium nitride (TiN), tantalum nitride / copper (Ti / Cu), tantalum nitride / copper (TaN / Cu), etc.

[0104] In some embodiments, the projection area of ​​the upper sub-pixel 50 electrically connected to the common conductor 90 inside the gap region 300 on the driving back plate 10 is at least partially located inside the projection area of ​​the gap region 300 on the driving back plate 10. This allows light emitted from the lower sub-pixel to be emitted directly through the periphery of the upper sub-pixel without being blocked, effectively reducing the obstruction of the lower sub-pixel's light-emitting surface, increasing the effective light-emitting area of ​​the lower sub-pixel, and facilitating the achievement of optimal light distribution.

[0105] Understandably, the projection of sub-pixel 50 onto the driving backplate 10 refers to the entire area enclosed by the outer edge of the projection.

[0106] Furthermore, such as Figure 2 As shown, the projection area of ​​the upper sub-pixel 50 electrically connected to the common conductive element 90 inside the gap region 300 on the driving backplate 10 is completely located within the projection area of ​​the gap region 300 on the driving backplate 10. This allows the light emitted by the sub-pixels outside the gap region to be emitted through the periphery of the upper sub-pixel without being blocked, minimizing the obstruction of the light-emitting surface of the lower sub-pixel, maximizing the effective light-emitting area of ​​the lower sub-pixel, and improving the light distribution effect. It also prevents the light emitted by the lower sub-pixel from being absorbed by the opaque bonding layer of the upper sub-pixel, thus preventing energy loss.

[0107] In some implementations, such as Figure 1 As shown, the microdisplay device also includes a first type of electrode contact 101, the first type of electrode contact 101 and the second type of electrode contact 102 having opposite polarities, and the bottom conductive layer 70 at the bottom end of any one of the two adjacent sub-pixels 50 forming the gap region 300 is electrically connected to at least one first type of electrode contact 101.

[0108] Furthermore, the bottom ends of two adjacent sub-pixels 50 forming the gap region 300 share a bottom conductive layer 70. The bottom surface of the shared bottom conductive layer 70 is electrically connected to the corresponding first type electrode contact 101, and the top surface is electrically connected to the common electrode conductive member 90 inside the gap region 300.

[0109] In a specific configuration, the common conductive element 90 inside the gap region 300 can be made to contact the aforementioned shared bottom conductive layer 70 at the bottom ends of the two adjacent sub-pixels 50 forming the gap region 300 to form an electrical connection.

[0110] In some implementations, the top conductive layer 60 of each sub-pixel 50 is electrically connected to the corresponding second type electrode contact 102 via a non-common conductive element 80.

[0111] Furthermore, the bottom end of the non-common conductive element 80 is in direct contact with the corresponding second type electrode contact 102.

[0112] The material of the non-cathode conductive member 80 can be the same as that of the cathode conductive member 90.

[0113] Further, the overall structure formed by the two adjacent sub-pixels 50 forming the gap region 300 is referred to as a first structure, the non-cathode conductive member 80 electrically connected to the top conductive layer 60 in the upper sub-pixel 50 electrically connected to the cathode conductive member 90 in the gap region 300 is located at the periphery of the first structure, and the non-cathode conductive member 80 electrically connected to the top conductive layer 60 in any one of the two adjacent sub-pixels 50 forming the gap region 300 is also located at the periphery of the first structure.

[0114] The upper sub-pixel 50 electrically connected to the cathode conductive member 90 in the gap region 300 and the second type of electrode contact 102 electrically connected to any one of the two adjacent sub-pixels 50 forming the gap region 300 are also located at the periphery of the first structure, and it can be understood that the second type of electrode contact 102 is also located outside the gap region 300.

[0115] Further, the non-cathode conductive member 80 corresponding to each sub-pixel 50 is electrically connected to the corresponding second type of electrode contact 102 after penetrating through the first layer of pixel layer 20, and the periphery of each non-cathode conductive member 80 in the first layer of pixel layer 20 is surrounded by an insulating medium to insulate and isolate the side wall of the adjacent sub-pixel 50, so as to avoid short circuit phenomenon of the adjacent sub-pixel itself.

[0116] In some embodiments, referring to Figure 2 The gap region 300 includes an annular region 3001, the cathode conductive member 90 is arranged in the annular region 3001, the side wall of each of the two adjacent sub-pixels 50 forming the gap region 300 has a groove portion 3002, and the annular region 3001 is enclosed between the groove portions 3002 of the two adjacent sub-pixels 50. This mode is more conducive to ensuring the arrangement of the non-cathode conductive member 80, and also makes the overall structure more compact, which is beneficial to improve the pixel density.

[0117] Further, the groove portion 3002 is arc-shaped, and other shapes can also be adopted.

[0118] In some embodiments, the bottom conductive layer 70 at the bottom end of the sub-pixel 50 can adopt a non-metal conductive layer.

[0119] In some embodiments, the bottom conductive layer 70 at the bottom end of the sub-pixel 50 can adopt a metal bonding layer.

[0120] Further, the upper part of the metal bonding layer can be provided with a metal fence, or without a metal fence.

[0121] In the case of having a metal fence, the following mode can be adopted:

[0122] The periphery of the at least one sub-pixel 50 is surrounded by a first peripheral metal fence 140, and the first peripheral metal fence 140 and the sidewall of the surrounded sub-pixel 50 are insulated and separated by a first insulating layer 150 to avoid internal short circuit of the sub-pixel.

[0123] For example, the first insulating layer 150 can be made of one or more of silicon oxide, aluminum oxide, silicon nitride, titanium oxide, hafnium oxide, tantalum oxide, niobium oxide, aluminum nitride, or gallium nitride.

[0124] In some schemes, the thickness of the first insulating layer 150 can be 5nm-2um.

[0125] The metal bonding layer at the bottom end of the sub-pixel 50 is integrally formed with the first peripheral metal fence 140, and the metal bonding layer will be sputtered to form a metal fence during etching, thereby achieving integral forming; or the metal bonding layer at the bottom end of the sub-pixel 50 is separately provided with the first peripheral metal fence 140.

[0126] In some embodiments, as shown in Figure 1 The bottom ends of the two adjacent sub-pixels 50 forming the gap region 300 share a bottom conductive layer 70, and the upper part of the shared bottom conductive layer 70 forms a first peripheral metal fence 140, and the two adjacent sub-pixels 50 forming the gap region 300 are surrounded by a first peripheral metal fence 140.

[0127] Further, the periphery of the upper sub-pixel 50 electrically connected to the top end of the common electrode conductive member 90 inside the gap region 300 is also surrounded by a first peripheral metal fence 140.

[0128] To achieve the insulation and separation of the first peripheral metal fence 140 of the upper sub-pixel 50 and the top conductive layer 60 of the sub-pixel, the top conductive layer 60 of the upper sub-pixel electrically connected to the top end of the common electrode conductive member 90 inside the gap region 300 and the first peripheral metal fence 140 of the sub-pixel are insulated and separated by a second insulating layer 160.

[0129] The material of the second insulating layer 160 can be the same as that of the first insulating layer 150.

[0130] In some embodiments, the first peripheral metal fence 140 can also be provided without a metal bonding layer at the bottom of the sub-pixel.

[0131] In some embodiments, a first insulating filling region 100 is provided inside the gap region 300, and the common electrode conductive member 90 inside the gap region 300 directly passes through the first insulating filling region 100 and is electrically connected to the first type of electrode contact 101.

[0132] The first structure can be prepared by filling the gap region 300 with an insulating material to form the first insulating filling region 100, so that the common electrode 90 directly passes through the first insulating filling region 100 and is electrically connected with the first electrode contact 101.

[0133] For example, the filling material of the first insulating filling region 100 can be one or a combination of silicon oxide, silicon nitride, silicon carbide (SiC), silicon carbon nitride (SiCN), phosphor silicon glass (PSG), boron phosphor silicon glass (BPSG), or polyimide.

[0134] Further, the first insulating filling region 100 can use a transparent filling material.

[0135] In the bottom common electrode structure, the top of the sub-pixel in the parent pixel located in different pixel layers is separately provided with a top conductive layer, which can be specifically provided in the following forms:

[0136] In some forms, the top conductive layer of the sub-pixel can be partially located on the side of the sub-pixel, for example, the setting of the top conductive layer 60 of the sub-pixel in the second pixel layer 30 in Figure 1

[0137] In another form, the top conductive layer 60 in at least one pixel layer is completely located above the corresponding sub-pixel in the pixel layer to which it is electrically connected, that is, the top conductive layer of the sub-pixel is completely located above the sub-pixel.

[0138] Further, the top conductive layer in the same pixel layer (the top conductive layer electrically connected with the sub-pixel in the same pixel layer) is located above the corresponding sub-pixel in the pixel layer to which it is electrically connected; here, the so-called "upper part" refers to being located near the top of the sub-pixel, and the sub-pixel includes a P-type semiconductor layer, an active layer, and an N-type semiconductor layer arranged in sequence along the Z direction, so that the so-called "upper part" can be understood as the lowest point of the top conductive layer being higher than the upper surface of the active layer in the sub-pixel. For example, the entire top conductive layer 60 of the sub-pixel in the first pixel layer is completely located above the sub-pixel 50, or the entire top conductive layer 60 of the sub-pixel in the first pixel layer is basically located at the upper part of the sub-pixel 50, only a part of the area is slightly lower than the top surface of the sub-pixel, as shown in Figure 9

[0139] ​​For example, a method for fabricating a top conductive layer 60 separately disposed at the top of a sub-pixel in the first pixel layer 20 includes: etching the sub-pixel in the first pixel layer 20, then backfilling the current pixel layer with an insulating medium, planarizing the top of the first pixel layer 20 after backfilling to expose the top of the sub-pixel in the pixel layer, and then depositing the top conductive layer 60 to make it contact the exposed area of ​​the sub-pixel top to achieve electrical connection. Then, an insulating medium can be deposited again on the pixel layer and planarized again, and then the upper pixel layer can be stacked. The upper pixel layer can also be fabricated with a top conductive layer 60 separately in the same way, that is, after etching the sub-pixel, an insulating medium is backfilled, and after backfilling, the top of the pixel layer is planarized to expose the top of the sub-pixel in the pixel layer, and then the top conductive layer 60 is deposited to achieve electrical connection. In this process, the insulating medium is always a transparent material.

[0140] The above-described fabrication method allows the top conductive layer of a sub-pixel to be located substantially at the top of the sub-pixel when the top conductive layer is set separately.

[0141] For example, see Figure 9 In the mother pixel, a separate top conductive layer 60 is provided at the top of the sub-pixel located in the first pixel layer 20, and the top conductive layer 60 in the first pixel layer 20 is completely above the corresponding sub-pixel 50 in the electrically connected first pixel layer; a separate top conductive layer 60 is also provided at the top of the sub-pixel located in the second pixel layer 30, and the top conductive layer 60 in the second pixel layer 30 is completely above the corresponding sub-pixel 50 in the electrically connected second pixel layer. Furthermore, the top conductive layers 60 of the two sub-pixels in the first pixel layer 20 are electrically connected to their respective second-type electrode contacts 102 through their respective non-common conductive elements 80, and the top conductive layer 60 of the sub-pixel in the second pixel layer 30 is electrically connected to another corresponding second-type electrode contact 102 through another non-common conductive element 80.

[0142] In some schemes, the color transfer layer 40 can be disposed above the top conductive layer 60 of the second layer and located on the light emission path of the corresponding sub-pixel in the first pixel layer to achieve color transfer of the emitted light color of the sub-pixel.

[0143] In some implementations, see Figure 9 To enhance current conduction capability, at least one metal reinforcement 190 may be provided on the top conductive layer 60.

[0144] The aforementioned metal reinforcement 190 can be located above or below the electrically connected top conductive layer 60. The metal reinforcements in different mother pixels can be shared or used independently by their respective mother pixels.

[0145] In some embodiments, the top end of the sub-pixel 50 is in contact with the top conductive layer 60, or the top end and at least part of the sidewall of the sub-pixel 50 are in contact with the top conductive layer 60.

[0146] In some embodiments, the light-emitting colors of the at least two sub-pixels are different, one of the sub-pixels 50 is located in the first layer of pixel layers 20, and the other sub-pixel 50 is located in the second layer of pixel layers 30.

[0147] Further, the light-emitting colors of the sub-pixels 50 in the first layer of pixel layers 20 and the second layer of pixel layers 30 are different.

[0148] For example, the sub-pixel 50 with a blue light-emitting color is referred to as a blue sub-pixel, the sub-pixel 50 with a green light-emitting color is referred to as a green sub-pixel, the sub-pixel 50 in the first layer of pixel layers 20 is a blue sub-pixel, the sub-pixel 50 in the second layer of pixel layers 30 is a green sub-pixel, a color conversion layer 40 is arranged above the blue sub-pixel in the first layer of pixel layers 20, the color conversion layer 40 is a red light color conversion layer, and the light emitted after color conversion by the color conversion layer 40 is red light. The blue sub-pixel without the color conversion layer arranged thereon is still blue light after being emitted through the second layer of pixel layers 30. Therefore, the light emitted through the second layer of pixel layers 30 is green light, blue light and red light, thereby realizing a three-color configuration.

[0149] In some embodiments, the upper portion of the second layer of pixel layers 30 can further be provided with a lens, and the lens covers at least one sub-pixel 50.

[0150] The following specifically describes Figure 1 The method for manufacturing the micro display device includes the following steps:

[0151] Step S1: providing a driving back plate 10, and the driving back plate 10 is provided with a second type of electrode contact 102;

[0152] and selecting a compound semiconductor layer as the pixel layer, the compound semiconductor layer being a layer with a certain thickness prepared by using a compound semiconductor material; for example, the compound semiconductor layer includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer arranged in sequence from top to bottom;

[0153] Step S2: stacking two layers of pixel layers in sequence from bottom to top above the driving back plate 10, the two layers of pixel layers being a first layer of pixel layers 20 and a second layer of pixel layers 30, respectively, and each layer of pixel layers is etched to obtain a sub-pixel 50 when the layer of pixel layers is stacked, the first layer of pixel layers 20 and the second layer of pixel layers 30 both use a compound semiconductor layer, so that each mother pixel includes a plurality of sub-pixels 50, part of the plurality of sub-pixels 50 are located in the first layer of pixel layers 20, and the remaining sub-pixels are located in the second layer of pixel layers 30.

[0154] It can be understood that each sub-pixel 50 obtained by etching includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer arranged in sequence from top to bottom.

[0155] and the top end of each sub-pixel 50 in the parent pixel is electrically connected to the corresponding second type of electrode contact 102 through the top conductive layer 60, and the bottom end of the plurality of sub-pixels 50 is interconnected through the bottom conductive layer 70 to form a bottom common electrode structure.

[0156] In the first layer of pixel layer 20, a gap region 300 is formed between the adjacent two sub-pixels 50, the gap region 300 is internally provided for the common electrode conductive member 90 to pass through, the bottom conductive layer 70 at the bottom end of the adjacent two sub-pixels 50 forming the gap region 300 is electrically interconnected, the bottom end of the common electrode conductive member 90 inside the gap region 300 is electrically connected to the bottom conductive layer 70 at the bottom end of any one of the adjacent two sub-pixels 50 forming the gap region 300, and the top end is electrically connected to the bottom conductive layer 70 of another sub-pixel 50 in the second layer of pixel layer 30; the light emitted by any one of the adjacent two sub-pixels 50 forming the gap region 300 is at least partially emitted through the periphery of the upper sub-pixel to which the common electrode conductive member 90 inside the gap region 300 is electrically connected.

[0157] And the color conversion layer 40 is further provided above the first layer of pixel layer 20, the color conversion layer 40 is located on the light emitting path of the corresponding sub-pixel 50 in the first layer of pixel layer 20 to realize the conversion of the light emitting color of the sub-pixel.

[0158] In some embodiments, when the color conversion layer 40 is prepared above the first layer of pixel layer 20, the color conversion material is coated at the upper surface of the top conductive layer 60 at the top end of the sub-pixel 50 which needs to be color converted, and the color conversion material is etched to obtain the color conversion layer 40, and the color conversion layer 40 obtained by preparation is located on the light emitting path of the corresponding sub-pixel 50 in the first layer of pixel layer 20.

[0159] In some embodiments, the method for forming a gap region 300 between the adjacent two sub-pixels 50 in the first layer of pixel layer 20 and allowing the common electrode conductive member 90 to pass through the gap region 300 includes: etching the first layer of pixel layer 20 to obtain two independent sub-pixels 50, and a gap region 300 is formed between the two sub-pixels 50; during the etching process, the bottom conductive layer 70 at the bottom end of the gap region 300 is not etched, so that the bottom ends of the two sub-pixels 50 share one bottom conductive layer 70, and the bottom surface of the shared bottom conductive layer 70 is electrically connected to the corresponding first type of electrode contact 101, and the top surface is used for electrically connecting to the common electrode conductive member 90 inside the gap region 300.

[0160] The process of sequentially stacking two pixel layers on the driving backboard 10 from bottom to top in step S2 can specifically include the following steps:

[0161] Step S201: refer to Figure 4 stacking the first layer of pixel layer 20 along the Z direction on the driving backboard 10;

[0162] The bottom of the first layer of pixel layer 20 is provided with a bottom conductive layer 70, which is a metal bonding layer. The first layer of pixel layer 20 and the driving backboard 10 are connected by the bottom conductive layer 70 to realize stacking, and the bonding method can be thermal compression bonding.

[0163] For example, the metal bonding layer can be a combination of metal materials, such as a combination of nickel (Ni), tin (Sn), gold (Au), copper (Cu), aluminum (Al), indium tin oxide (ITO), etc. For example, the metal bonding layer can be one or more of Ni, Sn combination, Au, Sn combination, Cu, Sn combination, Au, In combination, Au, Au combination, Al, Al combination, Cu, Cu combination or ITO, ITO combination. The metal bonding layer and the driving backboard 10 can also include an adhesion layer (material Cr, Ti, Ni, etc.) and a barrier depletion layer (material Ni, Pt, Cu, etc.). The metal bonding layer on the pixel layer and the driving backboard 10 can be symmetrical or asymmetrical.

[0164] In some preferred modes, the metal bonding layer can be a multi-layer structure stacked in the height direction, from bottom to top, respectively Cr layer (adhesion layer), Pt layer (barrier depletion layer), Au layer, Sn layer, Au layer, with thicknesses of 10 nm, 50 nm, 100 nm, 150 nm, and 50 nm, respectively.

[0165] In some schemes, the first layer of pixel layer 20 is also provided with a bottom ohmic contact layer 180, which is made of conductive material.

[0166] For example, the bottom ohmic contact layer 180 can be one or more of transparent conductive films such as indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium tin oxide (IGZO), aluminum-doped zinc oxide (AZO), etc. It can also be one or more of conductive metal materials such as nickel (Ni), chromium (Cr), gold (Au), silver (Ag), zinc (Zn), rhodium (Rh), beryllium (Be), aluminum (Al), etc. It can also be a composite structure composed of transparent metal oxide and metal; the thickness of the bottom ohmic contact layer 180 is in the range of 1 nm to 500 nm.

[0167] Step S202: refer to Figure 5In the b1 stage, the current pixel layer (compound semiconductor layer) is etched to obtain a sub-pixel 50, so as to realize the independence of the sub-pixel 50. It can be understood that the sub-pixel 50 obtained by etching includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer arranged in sequence from top to bottom; the thickness of the sub-pixel 50 (the distance between the upper surface of the N-type semiconductor layer and the lower surface of the P-type semiconductor layer) is 0.1 um to 5 um.

[0168] For example, the angle a of the sub-pixel 50 obtained by etching can be 90°±45°, and preferably, the angle a of the sub-pixel 50 can be 90°±20°. Wherein, the angle a of the sub-pixel 50 is the maximum angle between the sidewall of the sub-pixel 50 and the upper surface of the driving backboard 10.

[0169] The etching method can be dry etching such as ICP and RIE, or wet etching such as KOH and HCl.

[0170] It can be understood that a gap region 300 will be formed between the two adjacent sub-pixels 50 obtained by etching.

[0171] In some embodiments, before etching the pixel layer, an etching stop layer 230 is arranged at the top end of the pixel layer to serve as an etching mask. The etching stop layer 230 can be a transparent material. The etching stop layer 230 can be an insulating medium.

[0172] Step S203: refer to Figure 5 In the b2 stage, a first insulating layer 150 is deposited on the surface of the current pixel layer, so that the first insulating layer 150 covers the top surface and the sidewall of the sub-pixel 50, then the whole structure composed of two adjacent sub-pixels is taken as a first structure, and etching is continued on the periphery of the first structure to etch to the lower surface of the metal bonding layer to expose the second type of electrode contact 102; further, the metal bonding layer at the bottom end of the gap region 300 between the two sub-pixels 50 can be reserved, so that the two sub-pixels share a metal bonding layer at the bottom end.

[0173] For example, the first insulating layer 150 can be made of one or more of silicon oxide, aluminum oxide, silicon nitride, titanium oxide, hafnium oxide, tantalum oxide, niobium oxide, aluminum nitride or gallium nitride.

[0174] In some schemes, the thickness of the first insulating layer 150 can be 5 nm to 2 um.

[0175] During the etching of the metal bonding layer, a metal fence will be sputtered on the upper part of the metal bonding layer, at which time the metal fence and the metal bonding layer are integrally formed (see Figure 1), the metal fence is a first peripheral metal fence 140, for example, the overall structure composed of two adjacent sub-pixels 50 as a first structure, and the first peripheral metal fence 140 is arranged around the first structure, at this time, the two sub-pixels 50 in the first structure are surrounded by the same first peripheral metal fence 140.

[0176] At this time, the first peripheral metal fence 140 and the sidewall of the surrounded sub-pixel 50 are insulated and separated by the first insulating layer 150.

[0177] Step S204: the current pixel layer has at least two sub-pixels 50, a gap area 300 is formed between the two adjacent sub-pixels 50, and the insulating material is filled in the periphery of the sub-pixel 50, and the insulating material filled in the gap area 300 forms a first insulating filling area 100, and at the same time, the insulating material is also filled above the second type of electrode contact 102;

[0178] For example, the filling material of the first insulating filling area 100 can be one or a combination of silicon oxide, silicon nitride, silicon carbide (SiC), silicon carbon nitride (SiCN), phosphorus silicon glass (PSG), boron phosphorus silicon glass (BPSG), or polyimide.

[0179] Then, the preparation of the common electrode conductor 90 is performed: a hole is opened in the first insulating filling area 100 inside the gap area 300, and a metal material is backfilled to form the common electrode conductor 90, so that the common electrode conductor 90 directly penetrates through the first insulating filling area 100 and is electrically connected with the first type of electrode contact 101.

[0180] At the same time of performing the preparation of the common electrode conductor 90, the preparation of the non-common electrode conductor 80 is also performed, and the preparation is performed as follows: a hole is opened in the insulating material area above the second type of electrode contact, and a metal material is backfilled to form the non-common electrode conductor 80, so that the bottom end of the non-common electrode conductor 80 is electrically connected with the corresponding second type of electrode contact 102.

[0181] Step S205: refer to Figure 5 b3 stage in the middle of FIG. 12, a second layer of pixel layer 30 is stacked above the first layer of pixel layer 20;

[0182] First, repeat steps S202-S203 to complete the preparation of the sub-pixel 50 and the deposition of the first insulating layer 150, and make the bottom conductive layer 70 at the bottom end of the sub-pixel 50 in the second layer of pixel layer 30 contact the common electrode conductor 90 below;

[0183] Then, the electrode connection at the top end of the sub-pixel 50 can be performed: refer to Figure 5In the middle b4 stage, the top ends of two sub-pixels 50 in the first layer of pixel layers are exposed, and then a top conductive layer 60 is deposited or plated respectively, so that the top ends of the two sub-pixels 50 in the first layer of pixel layers are respectively in contact with the corresponding top conductive layer 60 to realize electrical connection and are electrically connected to the top ends of the corresponding non-co- pole conductive members 80 through the top conductive layer, and the bottom ends of the non-co-pole conductive members 80 are electrically connected to the corresponding second type of electrode contacts 102; and the top ends of the sub-pixels 50 in the second layer of pixel layers 30 are exposed, and the top conductive layer 60 is deposited or plated, so that the top ends of the sub-pixels 50 in the second layer of pixel layers are in contact with the corresponding top conductive layer 60 to realize electrical connection and are electrically connected to the top ends of the corresponding non-co-pole conductive members 80 through the top conductive layer, and the bottom ends of the non-co-pole conductive members 80 are electrically connected to the corresponding second type of electrode contacts 102.

[0184] It can be understood that, to expose the top ends of the sub-pixels 50 in the second layer of pixel layers 30 and the first layer of pixel layers 20, the excess material at the top ends of the sub-pixels 50 can be removed by etching.

[0185] Through the above process, the top conductive layer of each sub-pixel in the second layer and the first layer is respectively electrically connected to the corresponding second type of electrode contact 102 through the corresponding non-co-pole conductive member 80, and at the same time, the bottom conductive layer 70 of the sub-pixel 50 in the second layer of pixel layers 30 and the first layer of pixel layers 20 is interconnected through the co-pole conductive member 90, forming a bottom co-pole structure.

[0186] For example, the top conductive layer 60 is a transparent conductive layer, which is more conducive to light transmission, so that the light emitted by the lower sub-pixel 50 can pass through the top conductive layer 60 and be emitted upward. The transparent conductive layer can be one or a combination of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide (AZO), Al-doped indium tin oxide, Ag-doped indium tin oxide, and Au-doped indium tin oxide.

[0187] It can be understood that, when the sub-pixels 50 are prepared, if the top end of the sub-pixel 50 is also provided with an etching barrier layer 230, and the etching barrier layer 230 is an insulating layer, then when the electrical connection is performed, a notch needs to be provided on the etching barrier layer 230 to expose the top end of the sub-pixel 50, and the exposed area is in contact with the top conductive layer 60 to realize electrical connection.

[0188] When the sub-pixels 50 in the second layer of pixel layers 30 are prepared, referring to Figure 1 To realize the insulation and isolation between the first peripheral metal fence 140 of the sub-pixel 50 in the second layer of pixel layers 30 and the top conductive layer 60 thereof, a second insulating layer 160 can also be provided between the sidewalls of the first peripheral metal fence 140 and the top conductive layer 60; the material of the second insulating layer 160 can be the same as that of the first insulating layer 150.

[0189] In some embodiments, the thickness of the second insulating layer 160 is 5 nm to 2 μm.

[0190] Step S206: See Figure 5 In the middle b5 stage, the color transfer layer 40 is prepared. During preparation, a color transfer material is coated on the upper surface of the top conductive layer 60 at the top of the sub-pixel 50 that needs to be color transferred, and the color transfer material is etched to obtain the color transfer layer 40. The prepared color transfer layer 40 is located on the light-emitting path of the corresponding sub-pixel 50 in the first pixel layer 20.

[0191] After completing step S206, the lens can be fabricated.

[0192] The aforementioned lens is made of insulating material and can be made of materials such as silicon oxide, silicon nitride, aluminum oxide, silicate glass, silicone, electron beam photoresist (PMMA, SU8, etc.).

[0193] During lens fabrication, an insulating dielectric layer can be backfilled on the upper part of the second pixel layer 30, and the backfilled dielectric layer can be patterned and etched to form a lens.

[0194] Alternatively, a lens can be fabricated by filling the lens with an insulating dielectric material, planarizing it (CMP process), and then patterning it with a coating.

[0195] The LED display device of this embodiment simplifies the electrical connection structure, making it easier to manufacture. It also reduces the obstruction of the light-emitting surface of the lower sub-pixel, increases the effective light-emitting area of ​​the lower sub-pixel, and helps to achieve the best light distribution effect, so that its light pattern meets the needs of different application scenarios. At the same time, it also effectively improves the luminous efficiency and reliability of the display device.

[0196] Example 2

[0197] In this embodiment, the microdisplay device further includes a first type of electrode contact 101, the first type of electrode contact 101 and the second type of electrode contact 102 having opposite polarities, and the bottom conductive layer 70 at the bottom end of any one of the two adjacent sub-pixels 50 forming the gap region 300 is electrically connected to at least one first type of electrode contact 101.

[0198] In the first pixel layer 20 of the microdisplay device, a gap region 300 is formed between two adjacent sub-pixels 50. The common conductive element 90 inside the gap region 300 can be configured in the following ways:

[0199] The first type:

[0200] like Figure 1As shown, the bottom ends of two adjacent sub-pixels 50 forming the gap region 300 share a bottom conductive layer 70. The bottom surface of the shared bottom conductive layer 70 is electrically connected to the corresponding first type electrode contact 101, and the top surface is electrically connected to the common electrode conductive member 90 inside the gap region 300.

[0201] Furthermore, the common conductive element 90 inside the gap region 300 comes into contact with the common bottom conductive layer 70 and is electrically connected.

[0202] In some embodiments, a bottom ohmic contact layer 180 is provided between the bottom ends of two adjacent sub-pixels 50 forming the gap region 300 and a common bottom conductive layer 70, and the bottom ohmic contact layer 180 is penetrated by a common conductive element 90 inside the gap region 300.

[0203] The aforementioned bottom contact layer is made of conductive material.

[0204] In the above structure, the method of forming a gap region 300 between two adjacent sub-pixels 50 in the first pixel layer 20 and allowing the common electrode conductor 90 to pass through the gap region 300 includes: etching the first pixel layer 20 to obtain two independent sub-pixels 50, and forming a gap region 300 between the two sub-pixels 50; during the etching process, the bottom conductive layer 70 at the bottom end of the gap region 300 is retained without being etched, so that the bottom ends of the two sub-pixels 50 share a bottom conductive layer 70, the bottom surface of the shared bottom conductive layer 70 is electrically connected to the corresponding first type electrode contact 101, and the top surface is used to electrically connect to the common electrode conductor 90 inside the gap region 300.

[0205] The second type:

[0206] like Figure 6 As shown, the bottom end of the common electrode conductive element 90 inside the gap region 300 contacts the corresponding first type electrode contact 101 to achieve electrical connection, and the bottom conductive layer 70 of the bottom ends of the two adjacent sub-pixels 50 forming the gap region 300 are both electrically connected to the first type electrode contact 101 electrically connected to the bottom end of the common electrode conductive element 90.

[0207] Specifically, the bottom conductive layer 70 at the bottom of each of the two adjacent sub-pixels 50 forming the gap region 300 is electrically connected to the corresponding first-type electrode contact 101. The first-type electrode contact 101 electrically connected to the bottom of the two adjacent sub-pixels 50 forming the gap region 300 is electrically interconnected with the first-type electrode contact 101 electrically connected to the bottom of the common electrode 90. That is, the common electrode 90 is electrically connected to the bottom conductive layer 70 of the two sub-pixels forming the gap region 300 through the conductive interconnection between the various first-type electrode contacts 101.

[0208] In the above structure, the method for forming the gap region 300 between two adjacent sub-pixels 50 in the first layer of pixel layer 20 and allowing the common electrode conductor 90 to pass through the gap region 300 includes: etching the first layer of pixel layer 20 to obtain two independent sub-pixels 50, and forming the gap region 300 between the two sub-pixels 50; and during the etching, removing the bottom conductive layer 70 at the bottom end of the gap region 300 and exposing the first type of electrode contact 101 at the bottom end of the gap region 300, which is used for electrical connection with the common electrode conductor 90, so that the bottom conductive layer 70 at the bottom end of the above-mentioned two sub-pixels 50 is electrically connected to the first type of electrode contact 101 at the bottom end of the common electrode conductor 90. For example, the bottom conductive layer 70 at the bottom end of the above-mentioned two sub-pixels is respectively electrically connected to the corresponding first type of electrode contact 101, and the first type of electrode contact 101 electrically connected by the bottom end of the above-mentioned two sub-pixels is conductively interconnected with the first type of electrode contact 101 electrically connected by the bottom end of the common electrode conductor 90.

[0209] Embodiment Three

[0210] In this embodiment, referring to Figure 7 , the driving backboard 10 is divided into a display area 103, and all the parent pixels form a pixel array, and the projection of the pixel array on the driving backboard 10 is located inside the display area 103, that is, the display area 103 is the area where the pixel array is projected.

[0211] In some embodiments, the driving backboard 10 can also be provided with the first type of electrode contact 101, and the polarity of the first type of electrode contact 101 and the second type of electrode contact 102 is opposite.

[0212] The top end of each sub-pixel 50 in the parent pixel is respectively electrically connected to the corresponding second type of electrode contact 102 through the top conductive layer 60, and the bottom end of the plurality of sub-pixels 50 is interconnected through the bottom conductive layer 70 and connected to the first type of electrode contact 101 to form a bottom common electrode structure.

[0213] The first type of electrode contact 101 can be provided in the following ways:

[0214] The first way is to refer to Figure 1 , only the first type of electrode contact is provided inside the display area, and only the first type of electrode contact 101 is provided inside the display area 103, for example, the first type of electrode contact 101 can be provided in the local display area where each parent pixel is projected.

[0215] In some ways, referring to Figure 6The inner part of the display area 103 is provided with a plurality of first electrode contacts 101, which are electrically connected to each other. As shown in FIG. 1, the bottom conductive layer 70 of each of the two sub-pixels 50 in the gap area 300 of the first layer of pixel layer 20 is in contact with a corresponding first electrode contact 101, and the common electrode conductive member 90 in the gap area 300 is in direct contact with another first electrode contact 101. Each of the first electrode contacts 101 is electrically connected to each other.

[0216] Secondly, the first electrode contacts 101 are only arranged on the outer part of the display area 103. As shown in FIG. 2, the outer part of the display area 103 is provided with a peripheral electrode contact area 104, and the first electrode contacts 101 are arranged in the peripheral electrode contact area 104. Figure 7 As shown in FIG. 3, the outer part of the display area 103 is also provided with an interface 105, and the peripheral electrode contact area 104 is electrically connected to the interface 105. Figure 8

[0217] Thirdly, the first electrode contacts 101 are arranged on both the inner part and the outer part of the display area 103.

[0218] In some embodiments, the second electrode contacts 102 are electrically connected to the top conductive layer 60 of the top end of the corresponding sub-pixel 50 through a non-common electrode conductive member 80, and the bottom end of the non-common electrode conductive member 80 is in direct contact with the corresponding second electrode contact 102.

[0219] The micro display device of each of the above embodiments simplifies the electrical connection structure, is more conducive to preparation, can effectively increase the effective light-emitting area of the lower sub-pixel, is more conducive to the optimal light distribution effect, reduces energy waste, and thus effectively improves the light efficiency and reliability of the display device.

[0220] All the optional technical solutions described above can be combined to form optional embodiments of the present application, that is, any number of embodiments can be combined to meet the needs of different application scenarios, which are all within the protection scope of the present application, and will not be described one by one here.

[0221] It should be noted that the above embodiments are only examples for clear illustration, and are not a limitation on the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.​

Claims

1. A microdisplay device, characterized by: comprising a driving backplane, on which a second type of electrode contact is disposed; a first layer of pixel layer, which is stacked above the driving backplane; a second layer of pixel layer, which is stacked above the first layer of pixel layer; a parent pixel, which comprises a plurality of sub-pixels, some of which are located in the first layer of pixel layer and the rest of which are located in the second layer of pixel layer; a top end of each of the plurality of sub-pixels is electrically connected to a corresponding second type of electrode contact through a top conductive layer, and a bottom end of the plurality of sub-pixels is interconnected through a bottom conductive layer to form a bottom common electrode structure; wherein a gap region is formed between two adjacent sub-pixels in the first layer of pixel layer, a common electrode conductor passes through the gap region, the bottom conductive layers of the bottom ends of the two adjacent sub-pixels forming the gap region are electrically interconnected, a bottom end of the common electrode conductor inside the gap region is electrically connected to the bottom conductive layer of the bottom end of any one of the two adjacent sub-pixels forming the gap region, and a top end is electrically connected to the bottom conductive layer of another sub-pixel in the second layer of pixel layer; light emitted by any one of the two adjacent sub-pixels forming the gap region is at least partially emitted through the periphery of the upper sub-pixel to which the common electrode conductor inside the gap region is electrically connected.

2. The microdisplay device of claim 1, wherein: The upper side of the first layer of pixel layer is further provided with a color conversion layer, which is located on the light emitting path of the corresponding sub-pixel in the first layer of pixel layer.

3. The microdisplay device of claim 2, wherein: The color conversion layer is provided on the light emitting path of one of the two adjacent sub-pixels forming the gap region, and is not provided on the light emitting path of the other.

4. The microdisplay device of claim 1, wherein: The projection area of the upper sub-pixel electrically connected by the common electrode conductor inside the gap region on the driving backplane is at least partially located inside the projection area of the gap region on the driving backplane.

5. The microdisplay device of claim 1, wherein: The projection area of the upper sub-pixel electrically connected by the common electrode conductor inside the gap region on the driving backplane is completely located inside the projection area of the gap region on the driving backplane.

6. The microdisplay device of claim 1, wherein: It further comprises a first type of electrode contact, the polarity of which is opposite to that of the second type of electrode contact, and the bottom conductive layer of the bottom end of any one of the two adjacent sub-pixels forming the gap region is electrically connected to at least one first type of electrode contact.

7. The microdisplay device of claim 6, wherein: The bottom ends of the two adjacent sub-pixels forming the gap region share a bottom conductive layer, the bottom surface of the shared bottom conductive layer is electrically connected to a corresponding first type of electrode contact, and the top surface is electrically connected to the common electrode conductor inside the gap region.

8. The microdisplay device of claim 7, wherein: A bottom ohmic contact layer is further provided between the bottom ends of the two adjacent sub-pixels and the shared bottom conductive layer, and the bottom ohmic contact layer is penetrated by the common electrode conductor inside the gap region.

9. The microdisplay device of claim 6, wherein: The bottom end of the common electrode conductor inside the gap region is in contact with the corresponding first type of electrode contact to achieve electrical connection, and the bottom conductive layer of the bottom end of the two adjacent sub-pixels forming the gap region is electrically connected to the first type of electrode contact to which the bottom end of the common electrode conductor is electrically connected.

10. The microdisplay device of claim 1, wherein: The top conductive layer of each of the sub-pixels is electrically connected to the corresponding second type of electrode contact through a non-cathode conductive member.

11. The microdisplay device of claim 10, wherein: The bottom end of the non-cathode conductive member directly contacts the corresponding second type of electrode contact.

12. The microdisplay device of claim 1, wherein: The gap region comprises an annular region, the annular region is provided with the cathode conductive member, and the side walls of the two adjacent sub-pixels forming the gap region are each provided with a groove part, and the annular region is enclosed between the groove parts of the two adjacent sub-pixels.

13. The microdisplay device of claim 1, wherein: The bottom conductive layer adopts a metal bonding layer.

14. The microdisplay device of claim 1, wherein: The periphery of at least one of the sub-pixels is surrounded by a first peripheral metal fence, and the first peripheral metal fence and the side wall of the surrounded sub-pixel are insulated and separated by a first insulating layer.

15. The microdisplay device of claim 14, wherein: The bottom ends of the two adjacent sub-pixels forming the gap region share one bottom conductive layer, the upper part of the shared bottom conductive layer forms one first peripheral metal fence, and the two adjacent sub-pixels forming the gap region are surrounded by one first peripheral metal fence.

16. The microdisplay device of claim 1, wherein: The gap region is provided with a first insulating filling region inside, and the cathode conductive member inside the gap region directly penetrates through the first insulating filling region.

17. The microdisplay device of claim 1, wherein: The driving backplane is divided into a display region, all the parent pixels form a pixel array, the projection of the pixel array on the driving backplane is located inside the display region, the first type of electrode contact is arranged inside the display region, and / or the first type of electrode contact is arranged outside the display region.

18. The microdisplay device of claim 1, wherein: The top ends of the sub-pixels in the first layer of pixel layers and the second layer of pixel layers in the parent pixel are each provided with a top conductive layer, and the top conductive layer in the first layer of pixel layers is located above the electrically connected sub-pixel, and the top conductive layer in the second layer of pixel layers is located above the electrically connected sub-pixel.

19. The microdisplay device of claim 1, wherein: At least one of the top conductive layers is electrically connected with a metal reinforcing member.

20. The microdisplay device of claim 1, wherein: The light-emitting colors of at least two of the sub-pixels are different, one of the sub-pixels is located in the first layer of pixel layers, and the other of the sub-pixels is located in the second layer of pixel layers.

21. A method of fabricating a microdisplay device, comprising: The method comprises the following steps: A driving backplane is provided, and the driving backplane is provided with a second type of electrode contact; Two layers of pixel layers are sequentially stacked from bottom to top above the driving backplane, each layer of pixel layers is etched to obtain a sub-pixel during the stacking of each layer of pixel layers, the two layers of pixel layers are a first layer of pixel layers and a second layer of pixel layers, the first layer of pixel layers and the second layer of pixel layers each adopt a compound semiconductor layer, so that each parent pixel comprises a plurality of sub-pixels, part of the sub-pixels are located in the first layer of pixel layers, and the remaining sub-pixels are located in the second layer of pixel layers; The top end of each sub-pixel in the parent pixel is electrically connected to the corresponding second type of electrode contact through a top conductive layer, and the bottom ends of the plurality of sub-pixels are interconnected through a bottom conductive layer to form a bottom cathode structure; The top end of each sub-pixel in the parent pixel is electrically connected to the corresponding second type of electrode contact through a top conductive layer, and the bottom ends of the plurality of sub-pixels are interconnected through a bottom conductive layer to form a bottom cathode structure; The first layer of pixel layers, the gap area is formed between the two adjacent sub-pixels, the gap area inside for the common pole conductive member through, the bottom of the bottom of the two adjacent sub-pixels forming the gap area The conductive layer is conductively interconnected, the bottom of the common pole conductive member in the gap area is electrically connected to the bottom of the bottom conductive layer of any one of the two adjacent sub-pixels forming the gap area, and the top is electrically connected to the bottom conductive layer of another sub-pixel in the second layer of pixel layers;The light emitted by any one of the two adjacent sub-pixels forming the gap area is at least partially emitted via the periphery of the upper sub-pixel electrically connected by the common pole conductive member inside the gap area.

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