Microdisplay device and method of fabrication

Abstract

This invention relates to a microdisplay device and its fabrication method. The microdisplay device includes a driving backplane and multiple pixel layers. The driving backplane has second-type electrode contacts. Each parent pixel includes multiple sub-pixels. The top of each sub-pixel is electrically connected to a corresponding second-type electrode contact via a top conductive layer. The bottom ends of the multiple sub-pixels are interconnected via bottom conductive layers to form a bottom common-electrode structure. In two sub-pixels located in different pixel layers: a channel is formed inside one sub-pixel in the lower pixel layer, and a peripheral light-emitting area is formed around the channel. A common-electrode conductive element passes through the channel. The bottom end of the common-electrode conductive element inside the channel is electrically connected to the bottom conductive layer of the sub-pixel containing the channel, and the top end is electrically connected to the bottom conductive layer of the other sub-pixel in the upper pixel layer. This invention also discloses a fabrication method. This invention can effectively improve the luminous efficiency and reliability of the microdisplay device, meeting the needs of different application scenarios.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a microdisplay device and its fabrication method. Background Technology

[0002] Microdisplay devices, characterized by their small size, high resolution, and high brightness, can be applied in numerous fields such as AR / VR devices, automotive displays, medical detection, and smart wearables. Micro-LED and Micro-OLED technologies, in particular, have seen widespread development in recent years. Micro-LED technology, with its advantages of high efficiency, low power consumption, high density, and high stability, is considered one of the most promising next-generation display and light-emitting devices. In the field of microdisplays, to further ensure pixel size and density, multi-color stacking integration is required for color displays. Multi-layer stacked LED devices typically have a driving backplane (with driving circuitry) and multiple layers above it. Pixels are arranged in each layer, and each pixel needs to be electrically connected to the driving backplane. This results in a complex overall structure, significant loss of light-emitting area for each pixel, and difficulty in adjusting the light-emitting area, hindering optimal light distribution. Furthermore, the overall device consumes more power, which is detrimental to the reliability and stability of the LED display. Summary of the Invention

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

[0004] To address the aforementioned technical problems, the present invention provides a microdisplay device, comprising,

[0005] A drive backplate, wherein a second type of electrode contact is provided on the drive backplate;

[0006] Multiple pixel layers are stacked sequentially from bottom to top above the driving backplate;

[0007] A mother pixel, wherein the mother pixel comprises a plurality of sub-pixels, and at least two of the sub-pixels are located in different pixel layers;

[0008] The top of each sub-pixel is electrically connected to the corresponding second type of electrode contact through a top conductive layer, and the bottom ends of multiple sub-pixels are interconnected through a bottom conductive layer to form a bottom common electrode structure.

[0009] In two sub-pixels located in different pixel layers, a channel is formed inside one of the sub-pixels in the lower pixel layer. An outer light-emitting area is formed around the channel. A common electrode conductor passes through the channel. The bottom end of the common electrode conductor inside the channel is electrically connected to the bottom conductive layer of the sub-pixel where the channel is located, and the top end is electrically connected to the bottom conductive layer of the other sub-pixel in the upper pixel layer. At least part of the light emitted from the outer light-emitting area is emitted through the outer periphery of the upper sub-pixel electrically connected to the common electrode conductor inside the channel.

[0010] In one embodiment of the present invention, the top conductive layer of each sub-pixel is electrically connected to the corresponding second type of electrode contact via a non-common conductive element.

[0011] In one embodiment of the present invention, the bottom end of the non-common conductive element is in direct contact with the corresponding second type of electrode contact.

[0012] In one embodiment of the invention, the second type of electrode contact is located on the periphery of any of the sub-pixels having a channel.

[0013] In one embodiment of the present invention, the microdisplay device further includes a first type of electrode contact, the first type of electrode contact and the second type of electrode contact having opposite polarities, and the bottom conductive layer of the sub-pixel having a channel is electrically connected to at least one of the first type of electrode contacts.

[0014] In one embodiment of the present invention, the bottom conductive layer of the sub-pixel having a channel covers the bottom opening of the channel, and the common electrode conductive element inside the channel is electrically connected to the first type of electrode contact through the bottom conductive layer at the bottom end.

[0015] In one embodiment of the present invention, the bottom conductive layer of the sub-pixel having a channel is penetrated by the channel and surrounds the periphery of a common conductive element inside the channel, the common conductive element inside the channel being electrically connected to the first type of electrode contact.

[0016] In one embodiment of the present invention, the driving backplate is divided into a display area, all the mother pixels constitute a pixel array, the projection of the pixel array on the driving backplate is located inside the display area, the first type of electrode contact is provided inside the display area, and / or the first type of electrode contact is provided outside the display area.

[0017] In one embodiment of the invention, the sub-pixel having a channel and any of the sub-pixels above it connected to the common conductor passing through the channel are arranged coaxially; or, the sub-pixel having a channel and at least one of the sub-pixels above it connected to the common conductor passing through the channel are arranged off-axis.

[0018] In one embodiment of the present invention, a first insulating filling area is provided inside the channel, and the common electrode conductive element inside the channel passes directly through the first insulating filling area.

[0019] In one embodiment of the present invention, an inner air gap is provided inside the channel, the inner air gap surrounds the periphery of the common conductive element inside the channel, the inner air gap is formed inside the first insulating filling area, and the inner air gap is annular.

[0020] In one embodiment of the present invention, a compound semiconductor region is disposed inside the channel, and the common conductive element inside the channel passes through the compound semiconductor region.

[0021] In one embodiment of the present invention, an inner air gap is provided inside the channel, the inner air gap surrounding the periphery of the common conductive element inside the channel, and the inner air gap is formed between the peripheral light-emitting area and the compound semiconductor area in the sub-pixel having the channel.

[0022] In one embodiment of the invention, at least one of the sub-pixels is surrounded by a peripheral air gap, the peripheral air gap being annular.

[0023] In one embodiment of the present invention, the bottom conductive layer is a metal bonding layer.

[0024] In one embodiment of the invention, at least one of the sub-pixels is surrounded by a first peripheral metal fence, and the first peripheral metal fence and the outer sidewall of the surrounded sub-pixel are insulated from each other.

[0025] In one embodiment of the present invention, in the sub-pixel having a channel, a first inner metal fence is formed inside the channel, the first inner metal fence surrounds the periphery of the common conductive element inside the channel, and a first insulating layer covers the inner sidewall of the peripheral light-emitting area, and the first inner metal fence and the inner sidewall of the peripheral light-emitting area are insulated and isolated from each other by the first insulating layer.

[0026] In one embodiment of the present invention, the top conductive layer is separately provided at the top of each of the sub-pixels located in different pixel layers in the mother pixel, and the top conductive layer in the same pixel layer is located above the electrically connected sub-pixels.

[0027] In one embodiment of the invention, at least one of the top conductive layers is electrically connected to a metal reinforcement.

[0028] In one embodiment of the present invention, the top of each of the sub-pixels located in different pixel layers of the mother pixel is individually provided with the top conductive layer, and the top conductive layer in the same pixel layer is completely located above the electrically connected sub-pixels.

[0029] In one embodiment of the present invention, the microdisplay device has two pixel layers, namely a first pixel layer and a second pixel layer stacked from bottom to top, and a color conversion layer is disposed above the first pixel layer, the color conversion layer being located on the light emission path of the corresponding sub-pixel in the first pixel layer.

[0030] In one embodiment of the present invention, the color conversion layer is disposed on the light emission path of the sub-pixel having a channel in the first pixel layer.

[0031] In one embodiment of the invention, the color transfer layer at least covers a portion of the top of the peripheral light-emitting area in the sub-pixel having a channel.

[0032] In one embodiment of the present invention, the color conversion layer is disposed on the light-emitting path of the sub-pixels in the first pixel layer that do not have the aperture.

[0033] In one embodiment of the invention, at least two sub-pixels located in different pixel layers emit different colors.

[0034] In one embodiment of the invention, a lens is provided above the uppermost sub-pixel, and the lens covers at least one of the sub-pixels of the parent pixel.

[0035] This invention also discloses a method for fabricating a microdisplay device, comprising the following steps:

[0036] A drive backplane is provided, wherein a second type of electrode contact is provided on the drive backplane;

[0037] A compound semiconductor layer is selected as the pixel layer, and multiple pixel layers are stacked sequentially from bottom to top above the driving backplane. When stacking each pixel layer, the pixel layer is etched to obtain sub-pixels, so that each parent pixel includes multiple sub-pixels, and at least two sub-pixels are located in different pixel layers.

[0038] This ensures that the top of each sub-pixel in the mother pixel is electrically connected to the corresponding second type of electrode contact through the top conductive layer, and the bottom ends of multiple sub-pixels are interconnected through the bottom conductive layer to form a bottom common electrode structure.

[0039] And such that, among the two sub-pixels located in different pixel layers, a channel is formed inside one of the sub-pixels in the lower pixel layer, a peripheral light-emitting area is formed around the channel, a common electrode conductor passes through the channel, the bottom end of the common electrode conductor inside the channel is electrically connected to the bottom conductive layer of the sub-pixel where the channel is located, and the top end is electrically connected to the bottom conductive layer of the other sub-pixel in the upper pixel layer, and the light emitted from the peripheral light-emitting area is emitted at least partially through the periphery of the upper sub-pixel electrically connected to the common electrode conductor inside the channel.

[0040] In one embodiment of the present invention, when the common electrode conductive element passes through the inside of the channel, the preparation method further includes performing an opening process on the corresponding sub-pixel in the pixel layer to form a channel inside, and retaining the bottom conductive layer below the channel, such that the bottom conductive layer of the sub-pixel with the channel covers the bottom opening of the channel, and the common electrode conductive element passing through the channel is electrically connected to the bottom conductive layer below the channel.

[0041] In one embodiment of the present invention, when the common electrode conductive element passes through the channel, the preparation method further includes performing an opening process on the corresponding sub-pixel in the pixel layer to form a channel inside, and making the channel penetrate the bottom conductive layer below, the bottom conductive layer being penetrated surrounds the common electrode conductive element inside the channel, and making the common electrode conductive element passing through the channel electrically connected to the bottom conductive layer through a first type of electrode contact, wherein the polarities of the first type of electrode contact and the second type of electrode contact are opposite.

[0042] The technical solution of the present invention has the following advantages compared with the prior art:

[0043] The micro-display device of the present invention has a channel inside the corresponding sub-pixel, and a peripheral light-emitting area is formed around the channel. The common electrode conductive component passes through the channel. This structure can flexibly adjust the light-emitting area and position of the sub-pixel, and also helps to reduce the obstruction of the light-emitting surface of the lower sub-pixel, ensure the effective light-emitting area of ​​the lower sub-pixel, reduce energy waste, and thus achieve the best light distribution effect. It can effectively improve the luminous efficiency and reliability of the display device, and also make its light pattern meet the needs of different application scenarios. Attached Figure Description

[0044] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0045] Figure 1 This is a schematic diagram of the structure of the first micro-display device of the present invention (two-layer structure);

[0046] Figure 2 yes Figure 1A schematic diagram (top view) showing the arrangement of sub-pixels in the microdisplay device.

[0047] Figure 3 This is a schematic diagram (top view) showing another arrangement of sub-pixels in a microdisplay device.

[0048] Figure 4 yes Figure 1 The diagram shows a possible structure after a lens is installed.

[0049] Figure 5 yes Figure 1 A schematic diagram of another structure after the lens is installed in the shown structure;

[0050] Figure 6 This is a schematic diagram of the structure of the second type of microdisplay device of the present invention;

[0051] Figure 7 This is a schematic diagram of the structure of the third type of microdisplay device of the present invention;

[0052] Figure 8 This is a schematic diagram of the structure of the fourth micro-display device of the present invention;

[0053] Figure 9 This is a schematic diagram of the structure of the fifth micro-display device of the present invention;

[0054] Figure 10 This is a schematic diagram of the structure of the sixth type of microdisplay device of the present invention (three-layer structure).

[0055] Figure 11 yes Figure 10 A schematic diagram (top view) of one arrangement of sub-pixels in a microdisplay device is shown.

[0056] Figure 12 yes Figure 10 A schematic diagram of the arrangement of the top electrode layers of each sub-pixel (top view);

[0057] Figure 13 This is a schematic diagram (top view) of another arrangement of sub-pixels in a three-layer microdisplay device.

[0058] Figure 14 yes Figure 10 The diagram shows a structural schematic of the structure at one angle after a lens is installed.

[0059] Figure 15 yes Figure 10 A schematic diagram of the structure shown from another angle after a lens has been added;

[0060] Figure 16 This is a schematic diagram of the bonding between the driving backplate and the first pixel layer in this invention;

[0061] Figure 17 yes Figure 1 The flowchart shown is a fabrication process diagram of the microdisplay device.

[0062] Figure 18 yes Figure 9 The flowchart shown is a fabrication process diagram of the microdisplay device.

[0063] Figure 19 This is a schematic diagram of the structure of the seventh micro-display device of the present invention;

[0064] Figure 20 This is a schematic diagram (top view) of the distribution of the display area in this invention;

[0065] Figure 21 This is a schematic diagram (top view) of the connection between the peripheral electrode contact area and the interface in this invention.

[0066] Figure 22 This is a schematic diagram of the structure of the eighth micro-display device of the present invention;

[0067] Figure 23 This is a schematic diagram of the structure of the ninth type of microdisplay device of the present invention (with a color transfer layer).

[0068] Figure 24 This is a schematic diagram of the structure of the tenth microdisplay device of the present invention (equipped with a color transfer layer).

[0069] Explanation of reference numerals in the instruction manual:

[0070] 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;

[0071] 20. First pixel layer;

[0072] 30. Second pixel layer;

[0073] 40. Third pixel layer;

[0074] 50. Subpixel; 501. Aperture; 502. Peripheral luminous area;

[0075] 60. Top conductive layer;

[0076] 70. Bottom conductive layer;

[0077] 80. Non-common conductive components;

[0078] 90. Common electrode conductive component;

[0079] 100. First insulation filling area;

[0080] 110. Second insulation filling area;

[0081] 120. Compound semiconductor region;

[0082] 130. First inner metal fence; 140. First outer metal fence; 150. First insulating layer; 160. Second insulating layer; 170. Top ohmic contact layer; 180. Bottom ohmic contact layer; 190. Metal reinforcement; 210. Outer air gap; 220. Inner air gap; 230. Etching barrier layer; 250. Lens; 270. Color transfer layer; Detailed Implementation

[0083] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present disclosure or its application or use.

[0084] In the description of this invention, it should be understood that the terms "vertical," "upper," "lower," "top," "side," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0085] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0086] Traditional LED devices using multi-layer stacking have complex overall structures, resulting in significant loss of light-emitting area for each pixel. This makes it difficult to adjust the light-emitting area and achieve optimal light distribution. Furthermore, the overall device consumes more power, which is detrimental to the reliability and stability of the LED display device. In view of this, this application provides a micro-display device to improve the above-mentioned problems, thereby better ensuring the photoelectric performance and reliability of the LED display device.

[0087] It should be noted that, in this application, the compound semiconductor layer refers to a layer structure with a certain thickness prepared from compound semiconductor materials. Compound semiconductors generally refer to compounds formed from two or more elements, including crystalline inorganic compounds (such as III-V and II-VI compound semiconductors) and oxide semiconductors. The compound semiconductors involved in this application are mainly epitaxial materials for light-emitting diodes, such as InGaN ternary material systems or AlGaInP quaternary material systems, whose emission wavelengths can cover the entire spectrum from ultraviolet, visible, and infrared light. Their substrate materials can be GaN, Si, SiC, Sapphire, GaAs, InP, etc.

[0088] Taking the Micro-LED field as an example, some compound semiconductor materials involved in this application are shown in Table 1. In some practical applications, the film layers of compound semiconductors are more complex, or there are cases where materials are used interchangeably. Typical compound semiconductors mainly include P-type semiconductor materials, N-type semiconductor materials, and MQW active quantum wells and other functional layers (barrier layers, confinement layers, waveguide layers, buffer layers, etc.) sandwiched between the two:

[0089] Table 1. Material Table of Film Layers for Compound Semiconductors

[0090]

[0091] The structure of the microdisplay device of this application will be further described below with reference to the following specific embodiments.

[0092] Example 1

[0093] See Figure 1 This embodiment discloses a multi-layer stacked micro-display device, including at least one mother pixel, each mother pixel having multiple (two or more) sub-pixels. The structure of the above micro-display device is specifically described below using a mother pixel with two sub-pixels as an example. The structure shown in the figure only shows the case of one mother pixel. When there are multiple mother pixels, the internal structure of each mother pixel is basically the same.

[0094] In this application, the micro-display device has a Z-direction, an X-direction, and a Y-direction, which are perpendicular to each other. The Z-direction is the stacking direction of each layer of sub-pixels, that is, the up and down direction, which can also be understood as the direction away from / closer to the driving backplate. Here, "height" or "up and down" or "top and bottom" are all in the Z-direction.

[0095] In this invention, "bottom end of sub-pixel" refers to the end of the sub-pixel that is close to the driving backplate, and "top end of sub-pixel" refers to the end of the sub-pixel that is away from (away from) the driving backplate.

[0096] It should be noted that the cross-sectional views in the XZ plane in the accompanying drawings of this invention can be schematic diagrams after cutting a single cross section or schematic diagrams after cutting multiple cross sections together, in order to show the connection situation of different electrode contacts.

[0097] The LED display device in this embodiment includes a driving backplate 10 and a mother pixel, the mother pixel including a plurality of sub-pixels 50.

[0098] The driving backplate 10 is a component with a driving circuit. The first type of electrode contact 101 and the second type of electrode contact 102 are the lead-out terminals of the driving circuit, 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 backplate 10 and the sub-pixel 50, the connection between the sub-pixel 50 and the driving circuit is realized, thereby driving the sub-pixel 50 to emit light. This allows each sub-pixel 50 to be driven individually and emit light independently.

[0099] The aforementioned driving backplane 10 includes, but is not limited to, a CMOS (Complementary Metal Oxide Semiconductor) driving backplane 10.

[0100] The driving backplate 10 may be provided with a first type of electrode contact 101 and a second type of electrode contact 102. The polarities of the first type of electrode contact 101 and the second type of electrode contact 102 are opposite, with one being an anode and the other a cathode. Understandably, in order to prevent short circuits, the first type of electrode contact 101 and the second type of electrode contact 102 need to be insulated from each other. Through the provision of the first type of electrode contact 101 and the second type of electrode contact 102, the driving backplate 10 can be electrically connected to the sub-pixel 50, thereby controlling the light emission of each sub-pixel using the driving backplate.

[0101] Understandably, the two ends of sub-pixel 50 along the Z direction are the bottom and the top, respectively; the bottom and top of sub-pixel 50 are the two ends with opposite polarities. Sub-pixel 50 includes a P-type semiconductor layer, an active layer and an N-type semiconductor layer arranged sequentially along the Z direction. The active layer is used to emit light. The top of 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 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 of different polarities respectively.

[0102] See Figures 1-2 This embodiment discloses a microdisplay device, including a driving backplane 10, a mother pixel, and two pixel layers; wherein, Figure 1 It can be along Figure 2 Rotated sectional view at point AA;

[0103] The drive backplate 10 is provided with a second type of electrode contact 102;

[0104] Two pixel layers are stacked sequentially from bottom to top above the driving backplate 10 to form a two-layer structure. The two stacked pixel layers are the first pixel layer 20 and the second pixel layer 30 from bottom to top.

[0105] The mother pixel has two sub-pixels 50, and the two sub-pixels 50 are located in different pixel layers;

[0106] The top of each of the two sub-pixels 50 is electrically connected to the corresponding second type electrode contact 102 through the top conductive layer 60, and the bottom ends of the two sub-pixels are interconnected through the bottom conductive layer 70 to form a bottom common pole structure; that is, the bottom conductive layers 70 of each sub-pixel in the bottom common pole structure are electrically connected together and conduct electricity to each other.

[0107] In two sub-pixels 50 located in different pixel layers: a channel 501 is formed inside the sub-pixel 50 in the lower pixel layer, and an outer light-emitting area 502 is formed around the channel 501. A common electrode conductor 90 passes through the channel 501. The bottom end of the common electrode conductor 90 inside the channel 501 is electrically connected to the bottom conductive layer 70 at the bottom end of the sub-pixel 50 where the channel 501 is located, and the top end is electrically connected to the bottom conductive layer 70 of the other sub-pixel 50 in the upper pixel layer. In other words, a sub-pixel in the upper pixel layer can be electrically connected to the bottom conductive layer at the bottom end of the sub-pixel through the common electrode conductor passing through the lower sub-pixel.

[0108] The aforementioned "peripheral light-emitting area" is the area that can emit light after being powered on. To ensure that it emits light normally, the inner wall (side wall) of the peripheral light-emitting area and the common electrode conductive component inside the channel are insulated and isolated to avoid the common electrode conductive component from directly contacting the inner wall of the peripheral light-emitting area, which would cause a short circuit in the peripheral light-emitting area and prevent it from emitting light normally.

[0109] In this system, at least a portion of the light emitted from the peripheral light-emitting area 502 is emitted through the periphery of the upper sub-pixel electrically connected to the common conductive element 90 inside the channel 501 without being blocked by the upper sub-pixel. This effectively reduces the shading of the light-emitting surface of the lower sub-pixel (the sub-pixel area around the channel is the light-emitting area), increases the effective light-emitting area of ​​the lower sub-pixel, and facilitates the achievement of optimal light distribution. Figure 1 As shown in the figure, the direction of the dashed arrow indicates the light emission direction of the first layer of sub-pixels.

[0110] As is understood, in this invention, "upper pixel layer" refers to the 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 the sub-pixels located above the lowermost sub-pixel, while "lower sub-pixel" is the sub-pixel located below the upper sub-pixel.

[0111] In some implementations, such as Figures 2-3 As shown, in two sub-pixels 50 located in different pixel layers: the projection area of ​​the upper sub-pixel connected to the common conductive element 90 inside the channel 501 on the driving back plate 10 is the first projection area, and the projection area of ​​the peripheral light-emitting area 502 outside the channel 501 on the driving back plate 10 is the second projection area. The first projection area and the second projection area do not overlap at least partially. This method allows at least part of the light emitted from the peripheral light-emitting area to be emitted directly through the periphery of the upper sub-pixel connected to the common conductive element inside the channel without being blocked by it. This can effectively reduce the blocking of the light-emitting surface of the lower sub-pixel, increase the effective light-emitting area of ​​the lower sub-pixel, and help achieve the best light distribution effect.

[0112] 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. For example, Figure 2 In the structure shown, the sub-pixels 50 of the second layer and the first layer are both circular. The projection of the sub-pixel 50 of the second layer onto the driving backplate 10 refers to the entire area surrounded by its outer ring. The projection of the sub-pixel 50 of the second layer onto the driving backplate 10 refers to the entire area surrounded by its outer ring (including the internal channel area).

[0113] The above structure allows the common conductive element 90 of the upper sub-pixel to pass through the hole 501 inside the corresponding lower sub-pixel and be electrically connected to the bottom conductive layer 70 at its bottom end. This can effectively reduce the occlusion of the light-emitting surface of the lower sub-pixel, increase the effective light-emitting area of ​​the lower sub-pixel, and help achieve the best light distribution effect.

[0114] Furthermore, the sub-pixel distribution structure described above allows for more flexible design of the light-emitting area of ​​each sub-pixel layer, compensating for the shortcomings of certain sub-pixels being too bright or too dark. For example, by adjusting the size and position of the internal channels of the sub-pixels, the size and position of the peripheral light-emitting area can be flexibly adjusted, thereby achieving adjustment of the light-emitting area and region. This is suitable for different application requirements and makes it easier to adjust the light-emitting area. The structure also facilitates the control of the position of the upper sub-pixels, allowing the upper sub-pixels to be placed at different positions of the lower sub-pixels, thereby controlling the light pattern of the multi-color stacked device to meet the different needs of XR (extended reality) applications.

[0115] The above structure places the upper sub-pixel above the aperture of the lower sub-pixel. Compared to the lower sub-pixel without an aperture, this effectively reduces the obstruction of the light-emitting area of ​​the lower sub-pixel. It also reduces the problem of light blocking and absorption by the metal bonding layer on the lower sub-pixel when the metal bonding layer is placed at the bottom of the upper sub-pixel. This reduces the energy waste of the lower sub-pixel and the phenomenon of the device temperature becoming too high due to energy loss being converted into heat. This effectively increases the light efficiency and reliability of the display device.

[0116] 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.

[0117] Furthermore, the bottom end of the non-common conductive element 80 is in direct contact with the corresponding second type electrode contact 102.

[0118] Furthermore, the second type of electrode contact 102 is located around any sub-pixel having the channel 501 to better ensure the reliability of current transmission. Specifically, each second type of electrode contact 102 can be arranged around the periphery of the sub-pixel with the largest width (X direction).

[0119] In some embodiments, the microdisplay device further includes a first type of electrode contact 101, the first type of electrode contact 101 having opposite polarities to the second type of electrode contact 102, and the bottom conductive layer 70 of the sub-pixel 50 having the channel 501 being electrically connected to at least one first type of electrode contact 101. That is, the bottom conductive layer 70 of the sub-pixel 50 can be electrically connected to multiple first type of electrode contacts 101 simultaneously, or the bottom conductive layer 70 of the sub-pixel 50 can be electrically connected to only one first type of electrode contact 101.

[0120] The bottom conductive layer 70 of the sub-pixel 50 with aperture 501 can be set in the following manner:

[0121] The first type: such as Figure 1As shown, the bottom conductive layer 70 of the sub-pixel 50 with the aperture 501 covers the bottom opening of the aperture 501, and the common electrode conductive element 90 inside the aperture 501 is electrically connected to the first type electrode contact 101 through the bottom conductive layer 70 at the bottom end.

[0122] Furthermore, the common conductive element 90 inside the channel 501 comes into contact with the bottom conductive layer 70 at the bottom end to achieve electrical connection.

[0123] This method preserves the bottom conductive layer at the bottom of the channel without removing it, making it and the bottom conductive layer at the bottom of the peripheral light-emitting area a single, complete layer. This increases the conductive area and facilitates heat dissipation. It is also easier to fabricate.

[0124] The second type: such as Figure 6 As shown, the bottom conductive layer 70 of the sub-pixel 50 with the aperture 501 is penetrated by the aperture 501 and surrounds the periphery of the common electrode conductive member 90 inside the aperture 501. The common electrode conductive member 90 inside the aperture 501 is electrically connected to the first type of electrode contact 101.

[0125] This method requires removing the bottom conductive layer at the bottom of the channel during fabrication, which is equivalent to making a hole in the bottom conductive layer at the bottom of the sub-pixel. The hole area is directly below the channel, and only the bottom conductive layer at the bottom of the outer light-emitting area is retained.

[0126] In a specific configuration, if a sub-pixel 50 with a channel 501 is provided in the bottommost pixel layer, then multiple first-type electrode contacts 101 can be electrically connected to the bottom end of the sub-pixel 50. These first-type electrode contacts 101 are electrically interconnected, such that at least one first-type electrode contact 101 contacts the bottom conductive layer 70 at the bottom end of the sub-pixel 50 with the channel 501 in the bottommost pixel layer. Furthermore, at least one first-type electrode contact 101 directly contacts the common-polarity conductive element 90 inside the channel 501. Since the first-type electrode contacts 101 are electrically interconnected and conduct to each other, the common-polarity conductive element 90 inside the channel 501 can be electrically connected to the bottom conductive layer 70 at the bottom end of its first-type electrode contact 101 and the bottom end of the peripheral light-emitting area 502 through the first-type electrode contact 101 at its bottom end. Understandably, in this case, all of the aforementioned multiple first-type electrode contacts 101 can be located inside the display area 103.

[0127] In some implementations, see Figures 1-2 The sub-pixel 50 with the aperture 501 and any upper sub-pixel 50 connected to the common conductive element 90 passing through the aperture 501 are all coaxially arranged (the axes coincide). Figure 1 It can be Figure 2 A rotated sectional view of the middle structure along point AA; or, see [reference]. Figure 3The sub-pixel 50 with the aperture 501 and at least one upper sub-pixel 50 connected to the common conductive member 90 passing through the aperture 501 are arranged on opposite axes (the axes do not coincide). It should be noted that Figure 2 , Figure 3 In the first pixel layer 20, sub-pixel 50 is denoted as i1, and the second type of electrode contact 102 connected to it is denoted as k1. In the second pixel layer 30, sub-pixel 50 is denoted as i2, and the second type of electrode contact 102 connected to it is denoted as k2.

[0128] In some embodiments, the projection of the sub-pixel connected to the common conductive element 90 inside the aperture 501 onto the driving backplate 10 is the first projection area, and the projection area of ​​the sub-pixel with the aperture 501 onto the driving backplate 10 is the third projection area, such as... Figure 2 As shown, the first projection area can fall completely inside the third projection area. In this case, the area of ​​the first projection area can be smaller than the area of ​​the third projection area. For example, the maximum width (or outer diameter) of the sub-pixel 50 with the aperture 501 along the X direction can be greater than the maximum width (or outer diameter) of the sub-pixel 50 located above the common conductive member 90 inside the aperture 501 along the X direction, so as to better ensure the light output effect.

[0129] 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. For example, the projection of sub-pixel 50 with aperture 501 onto the driving backplate 10 refers to the entire area enclosed by the outer edge of the projection, including the aperture area.

[0130] The common conductive element 90 inside the channel 501 can pass through only one pixel layer of the corresponding sub-pixel 50, and each of the sub-pixels 50 that are passed through is provided with a channel 501 for the common conductive element 90 to pass through.

[0131] For example, in Figure 2 In the two-layer structure shown, the common electrode conductive element 90 of the sub-pixel 50 in the second pixel layer 30 passes through the sub-pixel 50 in the first pixel layer 20 and is electrically connected to the bottom conductive layer 70 at its bottom end. The corresponding sub-pixel 50 in the first pixel layer 20 has a channel 501 inside for the common electrode conductive element 90 to pass through.

[0132] In other embodiments, the common conductive element 90 inside the channel 501 can pass through multiple sub-pixels 50 of different pixel layers, and each sub-pixel through which it passes is provided with a channel 501 for the common conductive element 90 to pass through.

[0133] The shape of each sub-pixel is not limited; it can be a circle, ellipse, polygon (triangle, trapezoid, rectangle, etc.) or other shapes.

[0134] The common electrode conductive component 90 can 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.

[0135] The material of the non-common conductive component 80 can be the same as that of the common conductive component 90.

[0136] In some implementation schemes, such as Figure 1 As shown, the maximum width (or outer diameter) L1 of the aperture 501 along the X direction is greater than or equal to the maximum width (or outer diameter) of the upper sub-pixel 50 connected to the common conductive element 90 in the aperture 501 along the X direction, so as to better ensure the light-emitting area of ​​the sub-pixel with the aperture, improve the light-emitting effect, and also prevent the light emitted by the lower sub-pixel from being absorbed by the non-transparent bonding layer of the upper sub-pixel, resulting in energy loss.

[0137] In some ways, such as Figure 1 As shown, in a sub-pixel 50 having a channel 501: a first insulating filling area 100 is provided inside the channel 501, and the common conductive element 90 inside the channel 501 directly passes through the first insulating filling area 100 and contacts the bottom conductive layer 70 at the bottom end of the sub-pixel 50.

[0138] In some designs, a second insulating filler area 110 is provided around each sub-pixel 50, through which the non-common conductive component 80 can pass. The second insulating filler area 110 and the first insulating filler area 100 can be made of the same material.

[0139] In the bottom common-polarity structure, the top conductive layer is separately set at the top of each sub-pixel located in different pixel layers within the mother pixel. Specifically, the top conductive layer can be set in the following form:

[0140] In some configurations, the top conductive layer portion of a subpixel can be located on the side of the subpixel and extend to the bottom of the subpixel on that side. See [reference needed]. Figure 1 The way the top conductive layer 60 of the sub-pixel is set in the second pixel layer 30.

[0141] In other configurations, the top conductive layer 60 of at least one pixel layer is substantially located above the corresponding sub-pixel in the electrically connected pixel layer, that is, the top conductive layer of the sub-pixel is substantially located above the sub-pixel.

[0142] Specifically, the top conductive layer (the top conductive layer electrically connected to the sub-pixels in the same pixel layer) can be located above the corresponding sub-pixel in the electrically connected pixel layer. Here, "above" means located approximately near the top of the sub-pixel. The sub-pixel includes a P-type semiconductor layer, an active layer, and an N-type semiconductor layer arranged sequentially along the Z-direction (height direction). Therefore, "above" can be understood as ensuring that the lowest point of the top conductive layer is higher than the upper surface of the active layer in the sub-pixel. For example, see [reference needed]. Figure 23 In the first pixel layer, the entire top conductive layer 60 of the sub-pixel is located above the sub-pixel 50, or the entire top conductive layer 60 of the sub-pixel in the first pixel layer is located above the sub-pixel 50, with only a portion of it slightly below the top surface of the sub-pixel.

[0143] For example, the method for fabricating a separate top conductive layer 60 at the top of a sub-pixel 50 in the first pixel layer 20 includes the following steps: etching a 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, 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 top of the pixel layer and planarized again before stacking the upper pixel layer. The upper pixel layer can also be fabricated with a separate top conductive layer 60 using the same method, i.e., after etching the sub-pixel, backfilling with an insulating medium, planarizing the top of the pixel layer after backfilling to expose the top of the sub-pixel, and then depositing the top conductive layer 60 to achieve electrical connection. In this process, the insulating medium can be a transparent material.

[0144] The above-described fabrication method allows the top conductive layer of a sub-pixel to be located at the top of the sub-pixel when the top conductive layer is set separately.

[0145] For details, please refer to Figure 23 ,exist Figure 23 In the two-layer structure shown, a top conductive layer 60 is separately provided above each sub-pixel in the first pixel layer 20 and the second pixel layer 30. The top conductive layer 60 of the sub-pixel in the first pixel layer 20 is electrically connected to the corresponding second type electrode contact 102 through a non-common conductive element 80 on one side. 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 a non-common conductive element 80 on the other side.

[0146] In some embodiments, the sub-pixel 50 is in contact with the electrically connected top conductive layer 60 only at its top tip, or the top tip and at least part of the sidewalls of the sub-pixel 50 are in contact with the electrically connected top conductive layer 60.

[0147] In some embodiments, the bottom conductive layer 70 is a metal bonding layer.

[0148] Furthermore, a metal fence may or may not be provided on the upper part of the metal bonding layer.

[0149] When metal fences are available, they can be installed in the following ways:

[0150] The first type:

[0151] See Figure 1 At least one sub-pixel 50 is surrounded by a first peripheral metal fence 140, and the first peripheral metal fence 140 and the outer sidewall of the surrounded sub-pixel 50 are insulated from each other.

[0152] Understandably, the outer wall of subpixel 50 refers to the side wall at the outer periphery of subpixel 50. For example, if a hole 501 is opened inside subpixel 50, making subpixel 50 ring-shaped, then the outer wall of subpixel 50 refers to the ring-shaped outer wall.

[0153] Preferably, the aforementioned first outer metal fence 140 can be in the form of a ring structure. In some other embodiments, it can also be in the form of an arc.

[0154] Furthermore, a first insulating layer 150 is provided on the outer wall of the sub-pixel 50 surrounded by the first peripheral metal fence 140, and the first peripheral metal fence 140 and the outer wall of the surrounded sub-pixel 50 are insulated and isolated from each other by the first insulating layer 150.

[0155] In this embodiment, the metal bonding layer at the bottom of the sub-pixel 50 and the first peripheral metal fence 140 are integrally formed. The metal bonding layer will sputter to form the metal fence during the etching process, thereby achieving integral forming; or, the metal bonding layer at the bottom of the sub-pixel 50 and the first peripheral metal fence 140 are separately set and insulated from each other, and the two can be prepared separately.

[0156] The aforementioned first outer metal fence 140 can be set around the sub-pixel 50 with the aperture 501, or it can be set around the sub-pixel 50 without the aperture 501.

[0157] See Figure 1 To achieve insulation between the first outer metal fence 140 and the top conductive layer 60 of the upper sub-pixel 50, a second insulating layer 160 can be provided between the first outer metal fence 140 and the sidewall of 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.

[0158] The second type:

[0159] See Figure 6 In the sub-pixel 50 with a channel 501: a peripheral light-emitting area 502 is formed in the area surrounding the channel 501. A first inner metal fence 130 is formed inside the channel 501. The first inner metal fence 130 surrounds the common conductive element 90 inside the channel 501. A first insulating layer 150 covers the inner wall of the peripheral light-emitting area 502. The first inner metal fence 130 and the inner wall of the peripheral light-emitting area 502 are insulated and isolated by the first insulating layer 150 to avoid direct contact and cause a short circuit inside the peripheral light-emitting area.

[0160] Understandably, the inner wall of the peripheral light-emitting area 502 refers to the side wall facing the internal channel 501, that is, the side wall at its inner peripheral edge. For example, if the peripheral light-emitting area 502 is annular, then the inner wall of the peripheral light-emitting area 502 refers to the inner wall of the annular shape.

[0161] Furthermore, the aforementioned first inner metal fence 130 can be in the form of a ring structure. In some other cases, it can also be in the form of an arc.

[0162] For example, the first insulating layer 150 may be made of one or more materials selected from silicon oxide, aluminum oxide, silicon nitride, titanium oxide, hafnium oxide, tantalum oxide, niobium oxide, aluminum nitride, or gallium nitride;

[0163] In some designs, the thickness of the first insulating layer 150 can be 5 nm to 2 μm.

[0164] Furthermore, the metal bonding layer at the bottom of the sub-pixel 50 with the aperture 501 and the first inner metal fence 130 are integrally formed. The metal bonding layer will sputter to form the metal fence during the etching process, thereby achieving integral forming. At this time, the bottom conductive layer 70 inside the aperture 501 can be removed by etching. During the etching process, the first inner metal fence 130 will be sputtered to form inside the aperture 501. Its preparation method is basically the same as that of the first outer metal fence 140.

[0165] Alternatively, the metal bonding layer at the bottom of the sub-pixel 50 with the aperture 501 and the first inner metal fence 130 are separately disposed and insulated from each other; in this case, the first inner metal fence 130 can be fabricated separately. In this case, the first inner metal fence 130 can act as a metal reflector, so that light incident into the aperture 501 can be reflected back through the first inner metal fence 130, thereby better reducing the light loss of the outer light-emitting area 502.

[0166] Understandably, a sub-pixel 50 with a hole 501 can simultaneously have a first inner metal fence 130 and a first outer metal fence 140.

[0167] In some of these implementations, see Figure 7The top of sub-pixel 50 is provided with a top ohmic contact layer 170, and the top of each sub-pixel 50 is in contact with the corresponding top conductive layer 60 through the top ohmic contact layer 170.

[0168] The aforementioned top ohmic contact layer 170 can also be used as an etching barrier layer 230.

[0169] In some implementations, at least two sub-pixels 50 located in different pixel layers within a mother pixel have different emission colors. For example, in a two-layer structure with two pixel layers, the emission colors of sub-pixels in each pixel layer may be the same, and the emission colors of sub-pixels in different pixel layers may be different. Alternatively, one pixel layer may have two sub-pixels with different emission colors, while another pixel layer may have a sub-pixel whose emission color is different from that of at least one sub-pixel in the first layer.

[0170] For example, in some implementations, the sub-pixels 50 in different pixel layers of a multi-layer stacked structure emit different colors to achieve a color configuration.

[0171] For example, in the two-layer structure, the sub-pixels 50 in the first pixel layer 20 and the second pixel layer 30 emit different colors to achieve a dual-color configuration. For instance, the emission colors of each sub-pixel 50 from bottom to top are red and green, or they could be red and blue, or green and blue, etc.

[0172] In this embodiment, each sub-pixel 50 can be made of inorganic compound semiconductor material.

[0173] In some embodiments, to enhance current spreading capability, at least one top conductive layer 60 is electrically connected to a metal reinforcement 190.

[0174] The aforementioned metal reinforcement 190 can be located above or below the corresponding top conductive layer 60. The metal reinforcement 190 in different mother pixels can be shared or used independently by their respective mother pixels.

[0175] In some embodiments, a lens 250 is provided above the uppermost sub-pixel 50, and the lens 250 covers at least one sub-pixel 50 of the parent pixel. That is, the lens 250 and the sub-pixel 50 can correspond one-to-one, or one lens 250 can cover multiple sub-pixels 50.

[0176] Furthermore, the outer surface of lens 250 is curved, see reference. Figure 4 The bottom of the outer surface of lens 250 is in direct contact with the top conductive layer 60 of sub-pixel 50.

[0177] Or, see Figure 5The bottom of the outer surface of lens 250 is connected to the top conductive layer 60 of the corresponding sub-pixel 50 through an insulating medium at bb.

[0178] In this embodiment, both the first insulating filling area 100 and the second insulating filling area 110 can be made of transparent filling material.

[0179] The following explanation uses a mother pixel structure with two sub-pixels of 50 as an example. Figure 1 The method for fabricating the display device shown includes the following steps:

[0180] Step S1: Provide a drive backplate 10, on which a second type of electrode contact 102 is provided;

[0181] And a compound semiconductor layer is selected as the pixel layer. The aforementioned compound semiconductor layer is a layer with a certain thickness prepared using compound semiconductor materials; for example, the compound semiconductor layer here includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer arranged sequentially from top to bottom.

[0182] Step S2: Stack two pixel layers from bottom to top on the driving backplane 10. When stacking each pixel layer, etch the pixel layer to obtain sub-pixels 50, so that each parent pixel includes two sub-pixels 50, and the two sub-pixels 50 are located in different pixel layers. 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 from top to bottom.

[0183] This ensures that the top of each sub-pixel 50 in the mother pixel is electrically connected to the corresponding second type of electrode contact 102 through the top conductive layer 60, and the bottom ends of the two sub-pixels 50 are interconnected through the bottom conductive layer 70 to form a bottom common electrode structure.

[0184] And in two sub-pixels 50 located in different pixel layers, a channel 501 is formed inside one of the sub-pixels 50 in the lower pixel layer, and a peripheral light-emitting area 502 is formed around the channel 501. A common electrode conductor 90 passes through the channel 501. The bottom end of the common electrode conductor 90 inside the channel 501 is electrically connected to the bottom conductive layer 70 of the sub-pixel 50 where the channel 501 is located, and the top end is electrically connected to the bottom conductive layer 70 of the other sub-pixel 50 in the upper pixel layer. The light emitted by the peripheral light-emitting area 502 is at least partially emitted through the periphery of the upper sub-pixel 50 electrically connected to the common electrode conductor 90 inside the channel 501.

[0185] In some embodiments, when the common conductive element 90 passes through the channel 501, the above preparation method further includes: forming a channel 501 inside the corresponding sub-pixel 50 in the pixel layer by performing an opening process, and retaining the bottom conductive layer 70 below the channel 501, such that the bottom conductive layer 70 of the sub-pixel 50 with the channel 501 covers the bottom opening of the channel 501, and the common conductive element 90 passing through the channel 501 and the bottom conductive layer 70 below the channel 501 are electrically connected.

[0186] In some embodiments, when the common conductive element 90 passes through the interior of the channel 501, the above-described preparation method further includes: performing an opening process on the corresponding sub-pixel 50 in the pixel layer to form a channel 501 inside, and making the channel 501 penetrate the bottom conductive layer 70 below, the bottom conductive layer 70 being penetrated surrounds the periphery of the common conductive element 90 inside the channel 501, and making the common conductive element 90 passing through the channel 501 electrically connected to the bottom conductive layer 70 through a first type of electrode contact 101, wherein the polarities of the first type of electrode contact 101 and the second type of electrode contact 102 are opposite.

[0187] Step S2, which involves stacking two pixel layers sequentially from bottom to top (Z direction) on the driving backplate 10, can specifically include the following steps:

[0188] Step S201: Refer to Figure 16 The first pixel layer 20 is stacked along the Z direction on the driving backplate 10;

[0189] The first pixel layer 20 has a bottom conductive layer 70 at its bottom. This conductive layer is a metal bonding layer. The first pixel layer 20 and the driving backplate 10 are connected by bonding through the bottom conductive layer 70 to achieve stacking. The bonding method can be thermo-press bonding.

[0190] For example, the aforementioned metal bonding layer can be a combination of metal materials, such as 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 the following combinations: Ni and Sn, Au and Sn, Cu and Sn, Au and In, Au and Au, Al and Al, Cu and Cu, or ITO and ITO. The metal bonding layer and the driving backplate 10 may also include an adhesive layer (made of Cr, Ti, Ni, etc.) and a depletion barrier layer (made of Ni, Pt, Cu, etc.). The metal bonding layer on the pixel layer and the driving backplate 10 can be symmetrical or asymmetrical.

[0191] In some preferred embodiments, the aforementioned metal bonding layer can be a multilayer structure stacked sequentially along the height direction, with the layers from bottom to top being a Cr layer (adhesion layer), a Pt layer (barrier depletion layer), an Au layer, a Sn layer, and an Au layer, with thicknesses of 10 nm, 50 nm, 100 nm, 150 nm, and 50 nm, respectively.

[0192] In some designs, a bottom ohmic contact layer 180 is also provided at the bottom of the first pixel layer 20, which is made of a conductive material.

[0193] 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), and aluminum-doped zinc oxide (AZO), or one or more of conductive metal materials such as nickel (Ni), chromium (Cr), gold (Au), silver (Ag), zinc (Zn), rhodium (Rh), beryllium (Be), and aluminum (Al), or a composite structure composed of transparent metal oxides and metals; the thickness of the bottom ohmic contact layer 180 is in the range of 1 nm to 500 nm.

[0194] Step S202: See Figure 17 In stage b1, the current pixel layer (compound semiconductor layer) is etched to obtain sub-pixel 50, so as to achieve the independence of sub-pixel 50. It can be understood that the etched sub-pixel 50 includes an N-type semiconductor layer, an active layer and a P-type semiconductor layer arranged sequentially from top to bottom; the thickness of 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 0.1um to 5um; the width of sub-pixel 50 (X direction) is 0.2um to 80um.

[0195] For example, the angle α of the etched sub-pixel 50 can be 90°±45°, and preferably, the angle α of the sub-pixel 50 can be 90°±20°. Wherein, the angle α of the sub-pixel 50 is the maximum angle between the sidewall of the sub-pixel 50 and the upper surface of the driving backplate 10.

[0196] The above etching process can be carried out using dry etching methods such as ICP and RIE, or wet etching methods such as KOH and HCl.

[0197] Each mother pixel includes two sub-pixels 50, which emit different colors and are located in different pixel layers.

[0198] In some embodiments, an etching barrier layer 230 is provided at the top of the pixel layer before etching, serving as an etching mask. The etching barrier layer 230 can be a transparent material. It can be an insulating dielectric or a light-transmitting conductive layer material.

[0199] When etching the pixel layer (compound semiconductor layer) to obtain the sub-pixel 50, the corresponding sub-pixel 50 is also subjected to an opening process, so that a channel 501 is formed inside the sub-pixel 50.

[0200] During the hole-making process, the bottom of the hole 501 can be etched down to the upper surface of the bottom ohmic contact layer 180, so as to completely preserve the bottom conductive layer 70 at the bottom of the hole 501 without it being etched away.

[0201] Step S203: See Figure 17 In the middle 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, outer sidewall and inner sidewall of the channel 501 and bottom surface of the channel 501 of the sub-pixel 50. Then, etching is performed on the periphery of the sub-pixel 50 until the lower surface of the metal bonding layer is etched, and the second type of electrode contact 102 on the periphery of the sub-pixel 50 is exposed.

[0202] For example, the first insulating layer 150 may be made of one or more materials selected from silicon oxide, aluminum oxide, silicon nitride, titanium oxide, hafnium oxide, tantalum oxide, niobium oxide, aluminum nitride, or gallium nitride;

[0203] In some designs, the thickness of the first insulating layer 150 can be 5 nm to 2 μm.

[0204] During the etching process of the metal bonding layer, a metal fence is sputtered onto the top of the metal bonding layer, at which point the metal fence and the metal bonding layer are integrally formed (see...). Figure 1 For example, a first peripheral metal fence 140 is formed around sub-pixel 50.

[0205] The aforementioned metal fence can also be removed.

[0206] In other schemes, a metal fence can be fabricated separately on top of the metal bonding layer to act as a metal reflector.

[0207] Step S204: See Figure 17 In the middle b2 stage, insulating material is filled around the sub-pixel 50 with aperture treatment and inside the aperture 501, thereby forming a first insulating filling area 100 inside the aperture 501 and a second insulating filling area 110 around the sub-pixel 50.

[0208] For example, the filling material used in the first insulating filling region 100 and the second insulating filling region 110 can be one or more of silicon oxide, silicon nitride, silicon carbide (SiC), silicon carbon nitride (SiCN), silicon phosphosilicate glass (PSG), borosilicate glass (BPSG) or polyimide.

[0209] Understandably, after insulation filling, the height of the first insulation filling area 100 and the second insulation filling area 110 can be higher than the top of the sub-pixel 50, or flush with the top of the sub-pixel 50, or if the top of the sub-pixel 50 has an etch stop layer 230, it can also be flush with the etch stop layer 230.

[0210] Then, the common conductive element 90 is prepared: a hole is made in the first insulating filling area 100 inside the channel 501 and backfilled with metal material to form the common conductive element 90, so that the common conductive element 90 directly passes through the first insulating filling area 100 and contacts the bottom conductive layer 70 at the bottom end of the current sub-pixel 50 to achieve electrical connection.

[0211] When the common conductive component 90 is prepared, the non-common conductive component 80 is also prepared. During preparation, a hole is made in the second insulating filling area 110 around the channel 501 and backfilled with metal material to form the non-common conductive component 80, so that the bottom end of the non-common conductive component 80 is electrically connected to the corresponding second type electrode contact 102.

[0212] Step S205: See Figure 17 In the middle b3 stage, a second pixel layer 30 is stacked on top of the first pixel layer 20;

[0213] First, repeat steps S202-S203 to complete the preparation of sub-pixel 50 and the deposition of the first insulating layer 150, and make the bottom conductive layer 70 at the bottom of sub-pixel 50 in the second pixel layer 30 contact with the common electrode conductive component 90 below.

[0214] Then the electrode connection at the top of sub-pixel 50 can be performed: See Figure 17 In stage b4, the top of the sub-pixel 50 in the first pixel layer is exposed, and then a top conductive layer 60 is deposited or plated, such that one end of the top conductive layer 60 contacts the top of the first sub-pixel 50, and the other end contacts the corresponding non-common conductive element 80 to achieve electrical connection; at the same time, the top of the sub-pixel 50 in the second pixel layer 30 is exposed, and a top conductive layer 60 is deposited or plated, such that one end of the top conductive layer 60 contacts the top of the second sub-pixel 50, and the other end extends downward until it contacts the top of the corresponding non-common conductive element 80 to achieve electrical connection.

[0215] This process enables the second and first layer sub-pixels 50 to be electrically connected to the corresponding second type electrode contacts 102 through the corresponding non-common conductive elements 80, while the bottom conductive layers 70 of the sub-pixels 50 in the second pixel layer 30 and the first pixel layer 20 are interconnected through the common conductive elements 90 to form a bottom common structure.

[0216] Understandably, to expose the top of sub-pixel 50 in the second pixel layer 30 and the top of sub-pixel 50 in the first pixel layer 20, the excess material at the top of sub-pixel 50 can be removed by etching.

[0217] For example, the top conductive layer 60 is a transparent conductive layer to facilitate light transmission, allowing light emitted from the lower sub-pixel 50 to pass through the top conductive layer 60 and shine upwards. This transparent conductive layer can 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.

[0218] When fabricating sub-pixel 50, if an etch barrier layer 230 is provided at the top of sub-pixel 50, and a top ohmic contact layer 170 is provided between the etch barrier layer 230 and the top of sub-pixel 50, and the etch barrier layer 230 is a transparent conductive layer material, then during electrical connection, the etch barrier layer 230 at the top of sub-pixel 50 can be exposed, allowing the exposed area of ​​the etch barrier layer 230 to contact the top conductive layer 60 to achieve electrical connection; or, the top ohmic contact layer 170 at the top of sub-pixel 50 can be exposed (see...). Figure 7 This allows the exposed area of ​​the top ohmic contact layer 170 to come into contact with the top conductive layer 60, thereby achieving an electrical connection.

[0219] When preparing sub-pixels 50 in the second pixel layer 30, refer to... Figure 1 To achieve insulation between the first peripheral metal fence 140 of the sub-pixel 50 and the sidewall of the top conductive layer 60 in the second pixel layer 30, a second insulating layer 160 can be provided between the first peripheral metal fence 140 and the sidewall of 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.

[0220] In some embodiments, the thickness of the second insulating layer 160 is 5 nm to 2 μm.

[0221] After completing step S205, lens 250 can be fabricated (see [reference]). Figures 4-5 ).

[0222] The lens 250 mentioned above 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.).

[0223] During the fabrication of lens 250, 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 lens 250.

[0224] Alternatively, the lens 250 can be prepared by filling with an insulating dielectric material, planarizing it (CMP process), and then patterning it with a coating.

[0225] The LED display device of this embodiment simplifies the electrical connection structure, making it easier to manufacture. It can flexibly adjust the light-emitting area and position of the sub-pixels, which helps to reduce the shading of the light-emitting surface of the lower sub-pixels, increases the effective light-emitting area of ​​the lower sub-pixels, helps to reduce energy waste, achieves the best light distribution effect, and makes its light pattern meet the needs of different application scenarios. At the same time, it also effectively improves the luminous efficiency and reliability of the display device.

[0226] Example 2

[0227] like Figure 10 As shown, the main difference between this embodiment and Embodiment 1 is that the micro-display device in this embodiment has three pixel layers. All pixel layers are stacked sequentially from bottom to top above the driving backplate 10. At this time, the structure is a three-layer structure. The mother pixel has three sub-pixels 50. The three sub-pixels 50 are located in different pixel layers. The three pixel layers from bottom to top are the first pixel layer 20, the second pixel layer 30, and the third pixel layer 40.

[0228] The top of each of the three sub-pixels 50 is electrically connected to the corresponding second type electrode contact 102 through the top conductive layer 60, and the bottom of the three sub-pixels 50 are interconnected through the bottom conductive layer 70 to form a bottom common electrode structure.

[0229] In two sub-pixels 50 located in different pixel layers, a channel 501 is formed inside the lower pixel layer sub-pixel 50, and an outer light-emitting area 502 is formed around the channel 501. A common electrode conductor 90 passes through the channel 501. The bottom end of the common electrode conductor 90 inside the channel 501 is electrically connected to the bottom conductive layer 70 of the sub-pixel 50 where the channel 501 is located, and the top end is electrically connected to the bottom conductive layer 70 of the other sub-pixel 50 in the upper pixel layer. The light emitted from the outer light-emitting area 502 is at least partially emitted through the outer periphery of the upper sub-pixel 50 electrically connected to the common electrode conductor 90 inside the channel 501.

[0230] In some embodiments, the sub-pixel having the aperture 501 and any upper sub-pixel connected to the common conductor 90 passing through the aperture 501 are arranged coaxially; or, the sub-pixel having the aperture 501 and at least one upper sub-pixel connected to the common conductor 90 passing through the aperture 501 are arranged off-axis.

[0231] For example, the mother pixel has three sub-pixels 50, see [reference] Figures 10-11 ,in Figure 10 The middle structure can be Figure 11A rotated cross-sectional view at the middle EE; the bottommost sub-pixel 50 has a channel 501, and this sub-pixel 50 is coaxially arranged with the second layer sub-pixels 50 and also coaxially arranged with the third layer sub-pixels 50, that is, the three sub-pixels 50 are coaxially arranged; or refer to Figure 13 In the second pixel layer 30 and the third pixel layer 40, sub-pixel 50 is set on an off-axis compared to sub-pixel 50 in the first pixel layer 20. It should be noted that... Figure 10 , Figure 13 and Figure 14 In the first pixel layer 20, sub-pixel 50 is denoted as i1, and the connected second-type electrode contact 102 is denoted as k1. In the second pixel layer 30, sub-pixel 50 is denoted as i2, and the connected second-type electrode contact 102 is denoted as k2. In the third pixel layer 40, sub-pixel 50 is denoted as i3, and the connected second-type electrode contact 102 is denoted as k3. The shape of sub-pixel 50 is not limited.

[0232] Among them, Figure 10 In the three-layer structure shown, the top of each sub-pixel 50 is connected to its respective top conductive layer 60, as detailed in the reference. Figure 12 .

[0233] In some methods, two common conductive elements 90 can be present in the same channel 501. The bottom ends of these two common conductive elements 90 are in direct contact with the bottom conductive layer 70 of the sub-pixel where the channel 501 is located to achieve interconnection. Alternatively, the channel 501 and the common conductive element 90 can be in one-to-one correspondence.

[0234] In some embodiments, the common conductive element 90 inside the channel 501 may pass through only a sub-pixel in a single pixel layer, or it may pass through multiple sub-pixels in different pixel layers. Each sub-pixel 50 that is penetrated is provided with a channel 501 through which the common conductive element 90 passes.

[0235] For example, when making specific settings, refer to Figure 10The common conductive element 90 of the sub-pixel 50 in the third pixel layer 40 is divided into two segments, located in the second pixel layer 30 and the first pixel layer 20 respectively. The sub-pixels 50 in the second pixel layer 30 and the first pixel layer 20 are provided with a channel 501 for the common conductive element 90 to pass through. The bottom conductive layer 70 of the sub-pixel 50 in the third pixel layer 40 is finally in contact with the bottom conductive layer 70 of the sub-pixel 50 in the first pixel layer 20 through the common conductive element 90 to achieve electrical connection. The bottom conductive layer of the sub-pixel 50 in the second pixel layer 30 shares the same common conductive element 90 located in the first pixel layer 20 and finally in contact with the bottom conductive layer 70 of the sub-pixel 50 in the first pixel layer 20 to achieve electrical connection. Thus, the bottom conductive layer of each sub-pixel 50 in the third and second layers is electrically connected to the bottom conductive layer 70 of the first sub-pixel 50, thereby achieving bottom common polarity.

[0236] Or, see Figure 13 The common electrode conductive element 90 of the sub-pixel 50 in the third pixel layer 40 only passes through the sub-pixel 50 in the first pixel layer 20, but not through the sub-pixel 50 in the second pixel layer 30. The common electrode conductive element 90 of the sub-pixel 50 in the second pixel layer 30 only passes through the sub-pixel 50 in the first pixel layer 20. Each sub-pixel 50 in the first pixel layer 20 is provided with a channel 501 through which the common electrode conductive element 90 passes. At this time, the bottom conductive layer of each sub-pixel in the third and second layers is electrically connected to the bottom conductive layer 70 of the first sub-pixel 50 through its respective common electrode conductive element 90, and interconnection is achieved by the bottom conductive layer 70 of the first sub-pixel 50, thereby realizing bottom common electrode.

[0237] Alternatively, the common conductive element 90 of the sub-pixel 50 in the third pixel layer 40 can be made to penetrate only the sub-pixel 50 in the second pixel layer 30, but not the sub-pixel 50 in the first pixel layer 20. Instead, it can penetrate the sub-pixel 50 in the second layer, then penetrate the area surrounding the corresponding sub-pixel 50 in the first layer, and then connect to the bottom conductive layer 70 of the first sub-pixel 50.

[0238] In some implementations, see Figure 10 The second layer sub-pixel 50 has a second insulating fill area 110 around its periphery, through which the top conductive layer 60 of the first layer sub-pixel 50 passes. The second insulating fill area 110 and the first insulating fill area 100 can be made of the same material.

[0239] The shape of each sub-pixel 50 is not limited; it can be a circle, trapezoid, rectangle, or other shape.

[0240] In some implementations, a lens 250 is also provided above the topmost sub-pixel, and the lens 250 covers at least one sub-pixel 50 of the parent pixel. That is, the lens 250 and the sub-pixel 50 can correspond one-to-one, or one lens 250 can cover multiple sub-pixels 50.

[0241] For example, see Figures 14-15 A lens 250 is also installed on the upper part of the three-layer structure. Figure 14 and Figure 15 These are cross-sectional views taken from different angles. Figure 14 The diagram shows the connection between the top conductive layer 60 of the first and second sub-pixels. Figure 15 The diagram shows the connection between the top conductive layer 60 of the second and third sub-pixels.

[0242] In some implementations, in the three-layer structure, the sub-pixels in the first pixel layer 20, the second pixel layer 30, and the third pixel layer 40 emit different colors to achieve a three-color configuration. For example, the emission colors of each sub-pixel from bottom to top are red, green, and blue, respectively.

[0243] Example 3

[0244] In this embodiment, the common electrode conductive element 90 passes through the inside of the channel 501. The bottom end of the common electrode conductive element 90 inside the channel 501 is electrically connected to the bottom conductive layer 70 of the sub-pixel 50 where the channel 501 is located, and the top end is electrically connected to the bottom conductive layer 70 of another sub-pixel 50 in the upper pixel layer.

[0245] For example, the bottom corresponding sub-pixel has a hole 501 inside, and the bottom conductive layer 70 of the upper corresponding sub-pixel is electrically connected to the bottom conductive layer 70 at its bottom end through the hole 501 inside the bottom corresponding sub-pixel via a common conductive member 90.

[0246] The common conductive element 90 can be penetrated in the following ways:

[0247] The first type:

[0248] See Figure 1 The channel 501 has a first insulating filling area 100 inside, and the common conductive element 90 inside the channel 501 passes directly through the first insulating filling area 100.

[0249] Further, see Figure 8 An inner air gap 220 is provided inside the channel 501, which surrounds the common conductive element 90 inside the channel 501.

[0250] In some embodiments, an inner air gap 220 is formed inside the first insulating filling region 100, and the inner air gap 220 is annular. For example, it can be a circular ring, a square ring, etc., and the specific shape is not limited.

[0251] When the first structure described above is fabricated, the following fabrication method can be used: fill the inside of the channel 501 with insulating material to form a first insulating filling area 100, so that the common conductive element 90 directly passes through the first insulating filling area 100 and contacts the bottom conductive layer 70 at the bottom end of the sub-pixel 50 where the channel 501 is located.

[0252] When the insulating material is filled inside the channel 501 to form the first insulating filling area 100, an inner air gap 220 is formed inside it.

[0253] For example, the filling material used in the first insulating filling region 100 may be one or more of silicon oxide, silicon nitride, silicon carbide (SiC), silicon carbon nitride (SiCN), silicon phosphosilicate glass (PSG), borosilicate glass (BPSG), or polyimide.

[0254] By setting an inner air gap, it is easier for total internal reflection to occur when light enters the low-refractive-index air gap from the high-refractive-index sub-pixel corresponding film layer, thereby achieving optical angle modulation, reducing the light emission divergence angle, achieving light collimation, and thus improving the display brightness and light efficiency of the display device.

[0255] The second type:

[0256] See Figure 9 A compound semiconductor region 120 is provided inside the channel 501, and the common conductive element 90 inside the channel 501 passes through the compound semiconductor region 120.

[0257] Understandably, the compound semiconductor region 120 penetrated by the common conductive element 90 does not emit light when energized.

[0258] Furthermore, an inner air gap 220 is provided inside the channel 501, surrounding the common conductive element 90 inside the channel 501. In the sub-pixel 50 with the channel 501, the inner air gap 220 is formed between the peripheral light-emitting area 502 and the compound semiconductor area 120. The inner air gap 220 is annular. For example, it can be a circular ring, a square ring, etc., and the specific shape is not limited.

[0259] The second structure described above can be prepared using the following method: (See attached document) Figure 18An annular groove is formed inside the corresponding sub-pixel 50. Air is retained inside the annular groove to form an inner air gap 220. The compound semiconductor material surrounding the inner wall of the annular groove is retained to form a compound semiconductor region 120, so that the common conductive element 90 passes through the compound semiconductor region 120 and contacts the bottom conductive layer 70 at the bottom of the sub-pixel 50.

[0260] Furthermore, the inner wall of the peripheral light-emitting region 502 and the outer wall of the internal compound semiconductor region 120 are insulated from each other. For example, the inner wall of the peripheral light-emitting region 502 is covered with a first insulating layer 150.

[0261] Furthermore, a metal bonding layer is provided at the bottom of the compound semiconductor region 120. After passing through the compound semiconductor region 120, the common conductive component 90 contacts the bottom conductive layer 70 at the bottom end of the sub-pixel 50 through the corresponding metal bonding layer to achieve electrical connection.

[0262] In some other ways, such as Figure 22 As shown, an outer air gap 210 can also surround the corresponding sub-pixel 50. In some preferred embodiments, the outer air gap 210 can be annular, such as a circular ring, a square ring, etc., and the specific shape is not limited. The function of the outer air gap 210 is roughly the same as that of the inner air gap 220.

[0263] In some schemes, the sub-pixel 50 with the peripheral air gap 210 is further provided with a first peripheral metal fence 140, and the peripheral air gap 210 is provided between the first peripheral metal fence 140 and the outer wall of the sub-pixel 50.

[0264] For example, a sub-pixel 50 having an aperture 501 may be surrounded by an outer air gap 210. An outer air gap may also be provided around a sub-pixel 50 that does not have an aperture 501.

[0265] Example 4

[0266] In this embodiment, see Figure 20 The driving backplate 10 is divided into a display area 103. All the mother pixels form a pixel array. The projection of the pixel array on the driving backplate 10 is located inside the display area 103, which means that the display area 103 is the area where the pixel array projection is located.

[0267] In some embodiments, a first type of electrode contact 101 may also be provided on the drive backplate 10, wherein the polarity of the first type of electrode contact 101 and the second type of electrode contact 102 are opposite.

[0268] The top of each sub-pixel 50 in the mother pixel is electrically connected to the corresponding second type electrode contact 102 through the top conductive layer 60, and the bottom ends of multiple sub-pixels 50 are interconnected through the bottom conductive layer 70 and connected to the first type electrode contact 101 to form a bottom common electrode structure.

[0269] The first type of electrode contact 101 can be set in the following ways:

[0270] First type: See reference Figure 1 The first type of electrode contact 101 is provided only inside the display area 103. For example, the first type of electrode contact 101 can be provided in the local display area where each mother pixel is projected.

[0271] In some ways, see Figure 6 The display area 103 is provided with a plurality of first type electrode contacts 101, which are electrically interconnected. If a sub-pixel 50 with a channel 501 is provided in the bottom pixel layer, at least one first type electrode contact 101 can contact the bottom conductive layer 70 at the bottom end of the sub-pixel 50 with the channel 501 in the bottom pixel layer, and another first type electrode contact 101 can directly contact the common electrode conductive member 90 inside the channel 501.

[0272] The second type: See reference Figure 19 The first type of electrode contacts 101 are provided only on the outside of the display area 103, for example, such as Figure 20 As shown, a peripheral electrode contact area 104 is provided around the display area 103, and the first type of electrode contact 101 can be disposed within the peripheral electrode contact area 104; for example Figure 21 As shown, an interface 105 is also provided around the display area 103, and the peripheral electrode contact area 104 can be electrically connected to the interface 105.

[0273] The third type: both the exterior and interior of the display area 103 are provided with first-type electrode contacts 101.

[0274] In some embodiments, the second type of electrode contact 102 is electrically connected to the top conductive layer 60 at the top of the corresponding sub-pixel 50 via a non-common conductive element 80, and the bottom end of the non-common conductive element 80 can directly contact the corresponding second type of electrode contact 102.

[0275] Example 5

[0276] See Figure 24 The main difference between this embodiment and Embodiment 1 is that a color transfer layer 270 is also provided above the first pixel layer 20.

[0277] The microdisplay device in this embodiment has two pixel layers, namely a first pixel layer 20 and a second pixel layer 30 stacked from bottom to top. A color conversion layer 270 is also provided above the first pixel layer 20, and the color conversion layer 270 is located on the light emission path of the corresponding sub-pixel 50 in the first pixel layer 20.

[0278] In the above structure, the sub-pixel corresponding to the color transfer layer 270 and the sub-pixel of the aperture 501 can be the same sub-pixel or different sub-pixels. It can be understood that when the sub-pixel corresponding to the color transfer layer 270 and the sub-pixel of the aperture 501 are the same sub-pixel, when at least part of the light emitted from the peripheral light-emitting area 502 of the lower sub-pixel 50 is emitted through the periphery of the upper sub-pixel electrically connected to the common conductive element 90 inside the aperture 501, if the color transfer layer 270 is also located on the periphery of the upper sub-pixel, then part of the light emitted from the peripheral light-emitting area 502 can be directed to the color transfer layer 270 on the periphery of the upper sub-pixel before being emitted.

[0279] The color conversion layer 270 can be used to change the color of light emitted. For example, the light emitted by a sub-pixel 50 is blue. The light path of the blue sub-pixel is provided with the color conversion layer 270. When the light emitted by the blue sub-pixel hits the color conversion layer 270, the color conversion layer 270 will be excited and emit another color of light. For example, the blue light emitted by the blue sub-pixel may appear red after being converted and emitted by the color conversion layer 270.

[0280] The color-transfer layer 270 can be made of quantum dot material or phosphor material, so that it can be excited by external light to undergo color transfer and emit light of a specific color.

[0281] It should be noted that shorter wavelength light is generally used to excite the color transfer layer to undergo color transfer and emit longer wavelength light. For example, blue light can be used to excite the color transfer layer to eventually emit red light.

[0282] By setting a color conversion layer, the color of light emitted from certain sub-pixels at the bottom layer can be changed, thereby enabling the display device to present a color display effect. This also simplifies the overall structure of the device, makes it easier to manufacture, effectively improves the light efficiency and reliability of the display device, and allows its light pattern to meet the needs of different application scenarios.

[0283] In some implementations, the color transfer layer 270 is located above the top conductive layer 60 of the corresponding sub-pixel 50 in the first pixel layer 20.

[0284] In this embodiment, the sub-pixel corresponding to the color transfer layer 270 and the sub-pixel of the aperture 501 in the above structure can be the same sub-pixel or different sub-pixels. The color transfer layer 270 can be specifically configured in the following ways:

[0285] The first method: A color conversion layer 270 is set on the light-emitting path of the sub-pixel 50 with the aperture 501 in the first pixel layer 20.

[0286] Furthermore, the area located outside the aperture 501 in the sub-pixel 50 with aperture 501 forms a peripheral light-emitting area 502, and the color transfer layer 270 at least covers a portion of the top of the peripheral light-emitting area 502 in the sub-pixel 50 with aperture 501.

[0287] For example, the sub-pixel 50 with a blue emission color is referred to as the blue sub-pixel. The blue sub-pixel is set in the first pixel layer 20. The blue sub-pixel has a channel 501 inside, and a part of the upper surface of its peripheral light-emitting area 502 is covered by the red light color conversion layer 270 (see...). Figure 1 and Figure 3 If the blue light emitted from that area is converted into red light by the red light conversion layer 270, the area above the blue sub-pixel that is not covered by the color conversion layer 270 will still emit blue light. In addition, the first pixel layer 20 can also have other independent blue sub-pixels. The blue sub-pixels do not have holes 501 inside, and no color conversion layer 270 is set on the light path above them. The light they finally emit is still blue. For example, the first pixel layer 20 has two independent blue sub-pixels. One blue sub-pixel has a hole 501 and a color conversion layer 270 is set on the upper part of the blue sub-pixel, while the other blue sub-pixel does not have a hole 501 and no color conversion layer 270 is set on the light path above it.

[0288] The second method involves setting a color conversion layer 270 on the light-emitting path of the sub-pixel 50 in the first pixel layer 20 where no aperture 501 is opened.

[0289] For example, in the first pixel layer 20, two independent blue sub-pixels are set. One blue sub-pixel has an aperture 501 inside and no color conversion layer is set above it. The other blue sub-pixel does not have an aperture 501. Then, a red light color conversion layer can be set only above the blue sub-pixel without an aperture 501. The blue light emitted by this sub-pixel 50 is converted into red light after being converted by the red light color conversion layer. The blue sub-pixel with an aperture 501 is not covered by a color conversion layer and ultimately emits blue light. This makes the sub-pixels with different final emission colors individually controllable.

[0290] The area of ​​each sub-pixel in the mother pixel can be adjusted according to the brightness ratio requirements to achieve the best color display effect.

[0291] All the above-mentioned optional technical solutions can be combined in any way to form optional embodiments of the present invention. That is, any number of embodiments can be combined to meet the needs of different application scenarios. All of these are within the protection scope of this application and will not be described in detail here.

[0292] It should be noted that the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A microdisplay device, characterized in that: include, A drive backplate, wherein a second type of electrode contact is provided on the drive backplate; Multiple pixel layers are stacked sequentially from bottom to top above the driving backplate; A mother pixel, wherein the mother pixel comprises a plurality of sub-pixels, and at least two of the sub-pixels are located in different pixel layers; The top of each sub-pixel is electrically connected to the corresponding second type of electrode contact through a top conductive layer, and the bottom ends of multiple sub-pixels are interconnected through a bottom conductive layer to form a bottom common electrode structure. In two sub-pixels located in different pixel layers, a channel is formed inside one of the sub-pixels in the lower pixel layer. An outer light-emitting area is formed around the channel. A common electrode conductor passes through the channel. The bottom end of the common electrode conductor inside the channel is electrically connected to the bottom conductive layer of the sub-pixel where the channel is located, and the top end is electrically connected to the bottom conductive layer of the other sub-pixel in the upper pixel layer. The projection area of ​​the upper sub-pixel connected to the common electrode conductor inside the channel on the driving backplate is a first projection area, and the projection area of ​​the outer light-emitting area outside the channel on the driving backplate is a second projection area. The first projection area and the second projection area do not overlap at least partially, so that the light emitted by the outer light-emitting area is emitted at least partially through the outer periphery of the upper sub-pixel electrically connected to the common electrode conductor inside the channel.

2. The microdisplay device according to claim 1, characterized in that: The top conductive layer of each sub-pixel is electrically connected to the corresponding second type of electrode contact via a non-common conductive element.

3. The microdisplay device according to claim 2, characterized in that: The bottom end of the non-common conductive element is in direct contact with the corresponding second type of electrode contact.

4. The microdisplay device according to claim 2, characterized in that: The second type of electrode contact is located on the periphery of any of the sub-pixels having a channel.

5. The microdisplay device according to claim 1, characterized in that: It also includes a first type of electrode contact, the first type of electrode contact and the second type of electrode contact having opposite polarities, and the bottom conductive layer of the sub-pixel having a channel is electrically connected to at least one of the first type of electrode contacts.

6. The microdisplay device according to claim 5, characterized in that: The bottom conductive layer of the sub-pixel with the channel covers the bottom opening of the channel, and the common electrode conductor inside the channel is electrically connected to the first type of electrode contact through the bottom conductive layer at the bottom end.

7. The microdisplay device according to claim 5, characterized in that: The bottom conductive layer of the sub-pixel with the channel is penetrated by the channel and surrounds the periphery of the common electrode conductor inside the channel, and the common electrode conductor inside the channel is electrically connected to the first type of electrode contact.

8. The microdisplay device according to claim 5, characterized in that: The driving backplate is divided into display areas, and all the mother pixels constitute a pixel array. The projection of the pixel array onto the driving backplate is located inside the display area. The display area is provided with the first type of electrode contact inside, and / or the display area is provided with the first type of electrode contact outside.

9. The microdisplay device according to claim 1, characterized in that: The sub-pixel with the aperture and any of the sub-pixels above it connected to the common conductor passing through the aperture are arranged coaxially; or, the sub-pixel with the aperture and at least one of the sub-pixels above it connected to the common conductor passing through the aperture are arranged off-axis.

10. The microdisplay device according to claim 1, characterized in that: The channel has a first insulating filling area inside, and the common electrode conductive element inside the channel passes directly through the first insulating filling area.

11. The microdisplay device according to claim 10, characterized in that: An inner air gap is provided inside the channel, and the inner air gap surrounds the periphery of the common conductive element inside the channel. The inner air gap is formed inside the first insulating filling area and is annular.

12. The microdisplay device according to claim 1, characterized in that: A compound semiconductor region is disposed inside the channel, and the common conductive element inside the channel passes through the compound semiconductor region.

13. The microdisplay device according to claim 12, characterized in that: An inner air gap is provided inside the channel, and the inner air gap surrounds the common conductive element inside the channel. In the sub-pixel with the channel, the inner air gap is formed between the peripheral light-emitting area and the compound semiconductor area.

14. The microdisplay device according to claim 1, characterized in that: At least one of the sub-pixels is surrounded by a peripheral air gap, which is annular.

15. The microdisplay device according to claim 1, characterized in that: The bottom conductive layer is a metal bonding layer.

16. The microdisplay device according to claim 1, characterized in that: At least one of the sub-pixels is surrounded by a first peripheral metal fence, and the first peripheral metal fence and the outer wall of the surrounded sub-pixel are insulated from each other.

17. The microdisplay device according to claim 1, characterized in that: In the sub-pixel with a channel, a first inner metal fence is formed inside the channel. The first inner metal fence surrounds the periphery of the common conductive element inside the channel. The inner wall of the peripheral light-emitting area is covered with a first insulating layer. The first inner metal fence and the inner wall of the peripheral light-emitting area are insulated and isolated from each other by the first insulating layer.

18. The microdisplay device according to claim 1, characterized in that: Each of the sub-pixels located in different pixel layers of the mother pixel has a separate top conductive layer at its top, and the top conductive layers in the same pixel layer are all located on top of the electrically connected sub-pixels.

19. The microdisplay device according to claim 1, characterized in that: At least one of the top conductive layers is electrically connected to the metal reinforcement.

20. The microdisplay device according to claim 1, characterized in that: It has two pixel layers, namely a first pixel layer and a second pixel layer stacked from bottom to top. A color conversion layer is also provided above the first pixel layer, and the color conversion layer is located on the light emission path of the corresponding sub-pixel in the first pixel layer.

21. The microdisplay device according to claim 20, characterized in that: The color conversion layer is disposed on the light-emitting path of the sub-pixel with a channel in the first pixel layer.

22. The microdisplay device according to claim 21, characterized in that: The color transfer layer at least covers a portion of the top of the peripheral light-emitting area in the sub-pixel with the aperture.

23. The microdisplay device according to claim 20, characterized in that: The color conversion layer is disposed on the light-emitting path of the sub-pixels in the first pixel layer where no aperture is formed.

24. The microdisplay device according to claim 1, characterized in that: At least two of the sub-pixels located in different pixel layers emit different colors.

25. The microdisplay device according to claim 1, characterized in that... A lens is provided above the uppermost sub-pixel, and the lens covers at least one of the sub-pixels of the parent pixel.

26. A method for fabricating a microdisplay device, characterized in that: Includes the following steps: A drive backplane is provided, wherein a second type of electrode contact is provided on the drive backplane; A compound semiconductor layer is selected as the pixel layer, and multiple pixel layers are stacked sequentially from bottom to top above the driving backplane. When stacking each pixel layer, the pixel layer is etched to obtain sub-pixels, so that each parent pixel includes multiple sub-pixels, and at least two sub-pixels are located in different pixel layers. This ensures that the top of each sub-pixel in the mother pixel is electrically connected to the corresponding second type of electrode contact through the top conductive layer, and the bottom ends of multiple sub-pixels are interconnected through the bottom conductive layer to form a bottom common electrode structure. And such that, among the two sub-pixels located in different pixel layers, a channel is formed inside one of the sub-pixels in the lower pixel layer, an outer light-emitting area is formed around the channel, a common electrode conductor passes through the channel, the bottom end of the common electrode conductor inside the channel is electrically connected to the bottom conductive layer of the sub-pixel where the channel is located, and the top end is electrically connected to the bottom conductive layer of the other sub-pixel in the upper pixel layer, the projection area of ​​the upper sub-pixel connected to the common electrode conductor inside the channel on the driving back plate is a first projection area, and the projection area of ​​the outer light-emitting area outside the channel on the driving back plate is a second projection area, the first projection area and the second projection area do not overlap at least partially, so that the light emitted by the outer light-emitting area is at least partially emitted through the outer periphery of the upper sub-pixel electrically connected to the common electrode conductor inside the channel.

27. The preparation method according to claim 26, characterized in that: When the common electrode conductive element passes through the channel, the preparation method further includes making an opening process on the corresponding sub-pixel in the pixel layer to form a channel inside, and retaining the bottom conductive layer below the channel, so that the bottom conductive layer of the sub-pixel with the channel covers the bottom opening of the channel, and the common electrode conductive element passing through the channel is electrically connected to the bottom conductive layer below the channel.

28. The preparation method according to claim 26, characterized in that: When the common electrode conductive element passes through the channel, the preparation method further includes making an opening process on the corresponding sub-pixel in the pixel layer to form a channel inside, and making the channel penetrate the bottom conductive layer below. The bottom conductive layer that is penetrated surrounds the common electrode conductive element inside the channel, and the common electrode conductive element passing through the channel is electrically connected to the bottom conductive layer through a first type of electrode contact, wherein the polarities of the first type of electrode contact and the second type of electrode contact are opposite.

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