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 with multiple pixel layers stacked on it. Each parent pixel includes multiple sub-pixels. At least one pixel layer is a type-1 pixel layer, and the bottom ends of each sub-pixel in the type-1 pixel layer are electrically connected to a corresponding first-type electrode contact via an independent conductive block. The conductive block and the first-type electrode contact are one-to-one. In 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, and interconnecting conductive components pass through the channel. Light emitted from the peripheral light-emitting area is at least partially emitted through the periphery of the upper sub-pixel electrically connected to the interconnecting conductive components inside the channel. This invention also discloses a method for fabricating the microdisplay device. This invention can effectively improve the luminous efficiency and reliability of microdisplay devices, 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 first type of electrode contact is provided on the drive backplate;

[0006] Multiple pixel layers, all of which 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 of the sub-pixels located in different pixel layers in the mother pixel is electrically connected to the corresponding top conductive layer, and the bottom of each of the sub-pixels is electrically connected to the corresponding first type of electrode contact.

[0009] At least one pixel layer is a type I pixel layer, and the bottom of each of the sub-pixels in the type I pixel layer is electrically connected to the corresponding first type electrode contact through an independent conductive block, and the conductive block corresponds one-to-one with the first type electrode contact;

[0010] In 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. An interconnecting conductive component passes through the channel. The top end of the interconnecting conductive component inside the channel is electrically connected to the bottom end of the other sub-pixel in the upper pixel layer. The bottom end of the interconnecting conductive component inside the channel is electrically connected to the corresponding first type of electrode contact. At least part of the light emitted from the peripheral light-emitting area is emitted through the periphery of the upper sub-pixel electrically connected to the interconnecting conductive component inside the channel.

[0011] In one embodiment of the invention, the conductive block has an electrical contact area for electrical connection to the bottom end of the corresponding sub-pixel in the type-1 pixel layer, the area of ​​the electrical contact area being smaller than the area of ​​the bottom surface of the corresponding sub-pixel in the type-1 pixel layer to which it is electrically connected.

[0012] In one embodiment of the present invention, the top conductive layers at the top of the sub-pixels located in different pixel layers in the mother pixel are interconnected to form a top common electrode structure.

[0013] In one embodiment of the present invention, the top conductive layer is separately provided on the top of each of the sub-pixels located in different pixel layers in the mother pixel and is not shared, and the top conductive layer in the same pixel layer is located on the top of the electrically connected sub-pixels.

[0014] In one embodiment of the present invention, at least two of the sub-pixels in the mother pixel share a top conductive layer, and at least one sub-pixel in the top conductive layer is located in a different pixel layer.

[0015] In one embodiment of the invention, a metal reinforcement is further included, and the shared top conductive layer is electrically connected to the metal reinforcement.

[0016] In one embodiment of the invention, the metal reinforcement is located above the electrically connected top conductive layer.

[0017] In one embodiment of the invention, the metal reinforcement is located below the electrically connected top conductive layer.

[0018] In one embodiment of the invention, the metal reinforcement surrounds the periphery of one of the sub-pixels below the electrically connected top conductive layer.

[0019] In one embodiment of the present invention, the microdisplay device further includes a second type of electrode contact with a polarity opposite to that of the first type of electrode contact, wherein the top conductive layers of a plurality of sub-pixels in the mother pixel are all connected to the second type of electrode contact through a common conductive element.

[0020] In one embodiment of the present invention, the bottom end of the common electrode is in direct contact with the corresponding second type of electrode contact.

[0021] In one embodiment of the present invention, at least two of the sub-pixels in the mother pixel share a top conductive layer, and the common electrode conductive member is in direct contact with the shared top conductive layer to achieve electrical connection; or, the common electrode conductive member is electrically connected to the shared top conductive layer through a transition conductive member.

[0022] In one embodiment of the present invention, the top of each of the sub-pixels of at least two different pixel layers in the mother pixel is provided with a separate top conductive layer without sharing it. The common conductive element includes interconnecting conductive portions. Adjacent top conductive layers are interconnected through the interconnecting conductive portions to achieve electrical connection. At least one top conductive layer is in direct contact with the electrically connected interconnecting conductive portion to achieve electrical connection. Alternatively, at least one top conductive layer is electrically connected to the electrically connected interconnecting conductive portion through a metal reinforcement.

[0023] In one embodiment of the invention, the top of the sub-pixel is in contact with an electrically connected top conductive layer, or the top of the sub-pixel and at least a portion of its sidewalls are in contact with an electrically connected top conductive layer.

[0024] In one embodiment of the present invention, the bottom end of the sub-pixel in the type-1 pixel layer is electrically connected to its corresponding conductive block through a metal reflective layer.

[0025] In one embodiment of the present invention, the sub-pixel in the type-1 pixel layer is electrically connected to the metal reflective layer only at its bottom end, or the bottom end and at least part of the sidewalls of the sub-pixel in the type-1 pixel layer are electrically connected to the metal reflective layer.

[0026] In one embodiment of the present invention, a peripheral reflective portion is formed on the upper part of the metal reflective layer, and the peripheral reflective portion surrounds the sub-pixel in the type-1 pixel layer. The peripheral reflective portion and the outer sidewall of the surrounding sub-pixel are insulated and isolated by a first insulating layer.

[0027] In one embodiment of the present invention, a channel is formed inside one of the sub-pixels in one of the pixel layers of the type, and a peripheral light-emitting area is formed around the channel. An inner reflective portion is also formed on the upper part of the metal reflective layer. The inner reflective portion is located inside the channel and surrounds the periphery of the interconnecting conductive element inside the channel. The inner reflective portion and the inner sidewall of the peripheral light-emitting area are insulated and isolated by the first insulating layer.

[0028] In one embodiment of the present invention, the bottom end of the sub-pixel in the type-1 pixel layer is in direct contact with the metal reflective layer to achieve electrical connection; or the bottom end of the sub-pixel in the type-1 pixel layer is electrically connected to the metal reflective layer through an ohmic contact layer.

[0029] In one embodiment of the present invention, the top end of the interconnecting conductive element inside the channel is electrically connected to the bottom end of a sub-pixel in the upper layer of the first type of pixel layer via a conductive block, and the bottom end of the interconnecting conductive element inside the channel is electrically connected to the corresponding first type of electrode contact.

[0030] In one embodiment of the present invention, all of the pixel layers are type I pixel layers.

[0031] In one embodiment of the present invention, at least one pixel layer is a type II pixel layer, and the bottom end of the sub-pixel in the type II pixel layer is electrically connected to the corresponding first type electrode contact through a bottom conductive layer, and the bottom surface of the sub-pixel in the type II pixel layer is completely covered by the bottom conductive layer.

[0032] In one embodiment of the present invention, the bottom conductive layer is a metal bonding layer, a first peripheral metal fence is formed on the upper part of the metal bonding layer, the sub-pixel in the type-II pixel layer is surrounded by the first peripheral metal fence, and the first peripheral metal fence and the outer sidewall of the surrounded sub-pixel are insulated from each other.

[0033] In one embodiment of the present invention, a channel is formed inside one of the sub-pixels in one of the type-II pixel layers, a peripheral light-emitting area is formed around the channel, a first inner metal fence is formed inside the channel, the first inner metal fence surrounds the periphery of the interconnecting conductive element inside the channel, and the first inner metal fence and the inner sidewall of the peripheral light-emitting area are insulated from each other.

[0034] In one embodiment of the present invention, the sub-pixel having a channel and any of the sub-pixels above it connected to the internal interconnecting conductive member of 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 internal interconnecting conductive member of the channel are arranged off-axis.

[0035] In one embodiment of the present invention, a first insulating filling area is provided inside the channel, and the interconnecting conductive element inside the channel passes directly through the first insulating filling area.

[0036] In one embodiment of the present invention, a compound semiconductor region is disposed inside the channel, and the interconnecting conductive element inside the channel passes through the compound semiconductor region.

[0037] In one embodiment of the present invention, the projection area of ​​the upper sub-pixel connected to the interconnecting conductive element inside the channel on the driving back plate is a first projection area, and the projection area of ​​the peripheral light-emitting area outside the channel on the driving back plate is a second projection area, wherein the first projection area and the second projection area do not overlap at least partially.

[0038] In one embodiment of the invention, at least two sub-pixels located in different pixel layers emit different colors.

[0039] In one embodiment of the present invention, a lens is provided above the uppermost sub-pixel, and the lens covers at least one of the sub-pixels in the parent pixel.

[0040] In one embodiment of the present invention, the microdisplay device further includes a color conversion layer, which is located on the light emission path of a corresponding sub-pixel in a pixel layer.

[0041] In one embodiment of the present invention, the microdisplay device has two pixel layers, at least one of the two pixel layers being the type I pixel layer, and the color conversion layer being located above the corresponding sub-pixel in the lower pixel layer of the two pixel layers.

[0042] This invention discloses a method for fabricating a microdisplay device, comprising,

[0043] A drive backplane is provided, wherein a first type of electrode contact is provided on the drive backplane;

[0044] 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. Each pixel layer has sub-pixels, so that each parent pixel includes multiple sub-pixels, and at least two sub-pixels are located in different pixel layers.

[0045] This ensures that the top of each of the sub-pixels located in different pixel layers within the mother pixel is electrically connected to the corresponding top conductive layer, and the bottom of each of the sub-pixels is electrically connected to the corresponding first type of electrode contact.

[0046] At least one pixel layer is a type I pixel layer, and the bottom of each of the sub-pixels in the type I pixel layer is electrically connected to the corresponding first type electrode contact through an independent conductive block, and the conductive block corresponds one-to-one with the first type electrode contact;

[0047] In this embodiment, among the two sub-pixels located in different pixel layers, one of the sub-pixels in the lower pixel layer has an internal channel, and an external light-emitting area is formed around the channel. An interconnecting conductive component passes through the inside of the channel, and the top end of the interconnecting conductive component inside the channel is electrically connected to the bottom end of the other sub-pixel in the upper pixel layer. The bottom end of the interconnecting conductive component inside the channel is electrically connected to the corresponding first type of electrode contact. At least part of the light emitted from the external light-emitting area is emitted through the periphery of the upper sub-pixel electrically connected to the interconnecting conductive component inside the channel.

[0048] In one embodiment of the present invention, when stacking the type-1 pixel layer, the fabrication method includes,

[0049] A compound semiconductor layer is selected as a type I pixel layer. The compound semiconductor layer is etched to obtain sub-pixels, and independent conductive blocks are prepared so that the end of the sub-pixel in the type I pixel layer that is close to the driving backplane is electrically connected to the corresponding conductive block.

[0050] Then the prepared type I pixel layer is directly bonded to the driving backplane, or the prepared type I pixel layer is bonded to the pixel layer adjacent below it;

[0051] After bonding, the bottom ends of each sub-pixel in the first-type pixel layer are each electrically connected to the corresponding first-type electrode contact through an independent conductive block, and the conductive block corresponds one-to-one with the first-type electrode contact.

[0052] In one embodiment of the present invention, when the conductive block is prepared in the type-1 pixel layer, the preparation method includes covering an insulating medium at one end of the sub-pixel near the driving backplate in the type-1 pixel layer, and forming a filling hole in the insulating medium and filling the filling hole with a conductive material to obtain the conductive block, such that the end of the sub-pixel near the driving backplate in the type-1 pixel layer is electrically connected to the corresponding conductive block.

[0053] The technical solution of the present invention has the following advantages compared with the prior art:

[0054] The micro-display device described in this invention is easier to manufacture. It features channels within corresponding sub-pixels, with an outer light-emitting area formed around the channels. Interconnecting conductive components pass through the channels. This structure allows for flexible adjustment of the light-emitting area and position of the sub-pixels, reduces shading of the lower sub-pixel's light-emitting surface, ensures the effective light-emitting area of ​​the lower sub-pixels, reduces energy waste, and achieves optimal light distribution. This effectively improves the luminous efficiency and reliability of the display device and allows its light pattern to meet the needs of different application scenarios. Attached Figure Description

[0055] 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.

[0056] Figure 1 This is a schematic diagram of the structure of the first micro-display device of the present invention (two-layer structure);

[0057] Figure 2 This is a schematic diagram (top view) of the arrangement of sub-pixels in a micro-display device according to the present invention.

[0058] Figure 3 yes Figure 1 The diagram shows a possible structure after a lens is installed.

[0059] Figure 4 This is a schematic diagram of the structure of the second type of microdisplay device of the present invention;

[0060] Figure 5 yes Figure 1 A schematic diagram of the structure shown after the addition of metal reinforcement components;

[0061] Figure 6 This is a schematic diagram of the structure of the third type of microdisplay device of the present invention;

[0062] Figure 7 This is a schematic diagram of the structure of the fourth micro-display device of the present invention;

[0063] Figure 8 This is a schematic diagram of the structure of the fifth type of microdisplay device of the present invention (three-layer structure).

[0064] Figure 9 This is a schematic diagram of the structure of the sixth type of microdisplay device of the present invention (three-layer structure).

[0065] Figure 10 yes Figure 1 The flowchart shown is a fabrication process diagram of the microdisplay device.

[0066] Figure 11 This is a schematic diagram of the fabrication of the first structural form of a pixel layer (removing the etch barrier layer).

[0067] Figure 12 This is a schematic diagram of the fabrication of the second structure of a pixel layer (with part of the etching barrier layer retained).

[0068] Figure 13 This is a schematic diagram illustrating the fabrication of the third structure of a pixel layer;

[0069] Figure 14 yes Figure 13 A magnified view of a section at point M1;

[0070] Figure 15 This is a schematic diagram of the first type of structure in which a top conductive layer is independently set for a pixel layer;

[0071] Figure 16 yes Figure 15 A schematic diagram of a structure after adding a metal reinforcement component;

[0072] Figure 17 yes Figure 15 The diagram shows the structure after the interconnecting conductive parts are connected.

[0073] Figure 18 yes Figure 17 A schematic diagram of the structure shown after the addition of metal reinforcement components;

[0074] Figure 19 yes Figure 15 The diagram shows a different structure after adding a metal reinforcement.

[0075] Figure 20 yes Figure 15 A schematic diagram showing the connection between the top conductive layer and the second type of electrode contact in the structure shown.

[0076] Figure 21 This is a schematic diagram of the structure of the seventh micro-display device of the present invention (two-layer structure).

[0077] Figure 22 This is a schematic diagram of the structure of the eighth micro-display device of the present invention (two-layer structure).

[0078] Figure 23 This is a schematic diagram of the structure of the ninth type of microdisplay device of the present invention (two-layer structure).

[0079] Figure 24 This is a schematic diagram of the second type of structure where the top conductive layer is set independently in the type II pixel layer;

[0080] Figure 25 yes Figure 24 A schematic diagram of the structure shown after the addition of metal reinforcement components;

[0081] Figure 26 yes Figure 15 The diagram shows the structure after the common electrode is connected.

[0082] Figure 27 yes Figure 26 A schematic diagram of the structure shown after the addition of metal reinforcement components;

[0083] Figure 28 This is a schematic diagram of a third type of structure in which the top conductive layer is set independently in the second type of pixel layer (the top of the sub-pixel and part of the sidewall are in contact with the top conductive layer).

[0084] Figure 29 This is a schematic diagram of the structure of the microdisplay device of the present invention when it is stacked in two layers (before the top conductive layer is prepared).

[0085] Figure 30 This is a schematic diagram of the structure of the tenth micro-display device of the present invention (two-layer structure).

[0086] Figure 31 This is a schematic diagram of the structure of the eleventh micro-display device of the present invention (two-layer structure).

[0087] Figure 32 This is a schematic diagram of a micro-display device of the present invention when it has a color transfer layer;

[0088] Figure 33 This is another structural schematic diagram of the micro-display device of the present invention when it has a color transfer layer;

[0089] Explanation of reference numerals in the instruction manual:

[0090] 10. Drive backplate; 101. Type I electrode contact;

[0091] 20. First pixel layer;

[0092] 30. Second pixel layer;

[0093] 40. Third pixel layer;

[0094] 50. Subpixel; 501. Aperture; 502. Peripheral luminous area;

[0095] 60. Top conductive layer;

[0096] 70. Bottom conductive layer;

[0097] 80. Non-common conductive components;

[0098] 90. Common conductor; 901. Interconnecting conductor;

[0099] 100. First insulation filling area;

[0100] 110. Second insulation filling area;

[0101] 130, First inner metal fence; 140, First outer metal fence; 150, First insulating layer; 160, Second insulating layer; 190, Metal reinforcement; 200, Transition conductive element; 230, Etching barrier layer; 250, Lens; 270, Conductive block; 2701, Electrical contact area; 280, Metal reflective layer; 2801, Outer reflective part; 2802, Inner reflective part; 290, Ohmic contact layer; 300, Transition block; 310, Substrate; 320, Color transfer layer; Detailed Implementation

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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:

[0108] Table 1. Material Table of Film Layers for Compound Semiconductors

[0109]

[0110] The structure of the microdisplay device of this application will be further described below with reference to the following specific embodiments.

[0111] Example 1

[0112] 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.

[0113] In this invention, the micro-display device has Z, X, and Y directions, which are perpendicular to each other. The Z direction is the stacking direction of each layer of sub-pixels, that is, the vertical direction, which can also be understood as the direction away from / closer to the driving backplate. Here, "height," "up / down," or "top / bottom" all refer to the Z direction. The "bottom end" can be understood as the end closer to the driving backplate, and the "top end" can be understood as the end away from (away from) the driving backplate.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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 are the lead-out terminals of the driving circuit, which are used to electrically connect the driving circuit and the sub-pixel 50. The sub-pixel 50 is a light-emitting element. Through the electrical connection between the driving 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.

[0118] The aforementioned driving backplane 10 includes, but is not limited to, a CMOS (Complementary Metal Oxide Semiconductor) driving backplane.

[0119] The driving backplate 10 may be provided with a first type of electrode contact 101 and a second type of electrode contact (not shown in the figure). The first type of electrode contact 101 and the second type of electrode contact have opposite polarities, one being the anode and the other the cathode. Understandably, in order to prevent short circuits, the first type of electrode contact 101 and the second type of electrode contact need to be insulated from each other. By setting the first type of electrode contact 101 and the second type of electrode contact, 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 10.

[0120] 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.

[0121] See Figure 1 This embodiment discloses a microdisplay device, including a driving backplate 10, a mother pixel, and two pixel layers;

[0122] The drive backplate 10 is provided with a first type of electrode contact 101;

[0123] 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.

[0124] The mother pixel has two sub-pixels 50, and the sub-pixels 50 with different emission colors are located in different pixel layers;

[0125] The top of each sub-pixel 50 located in different pixel layers of the mother pixel is electrically connected to the corresponding top conductive layer 60, and the bottom of each sub-pixel 50 is electrically connected to the corresponding first type of electrode contact 101.

[0126] At least one of the two pixel layers is a type I pixel layer. The bottom end of each sub-pixel 50 in the type I pixel layer is electrically connected to the corresponding first type electrode contact 101 through an independent conductive block 270. The conductive block 270 and the first type electrode contact 101 correspond one-to-one. This method can be called an alignment bonding connection method. Further, the conductive block 270 has an electrical contact area 2701 for electrical connection with the bottom end of the corresponding sub-pixel 50 in the type I pixel layer. The area of ​​the electrical contact area 2701 is smaller than the area of ​​the bottom surface of the corresponding sub-pixel 50 in the type I pixel layer to which it is electrically connected, so it does not need to contact the entire bottom surface of the sub-pixel.

[0127] In two sub-pixels 50 located in different pixel layers, a channel 501 is formed inside the lower sub-pixel 50, and an outer light-emitting area 502 is formed around the channel 501. An interconnecting conductive component passes through the channel 501. The top end of the interconnecting conductive component inside the channel 501 is electrically connected to the bottom end of the other sub-pixel 50 in the upper pixel layer, and the bottom end of the interconnecting conductive component inside the channel 501 is electrically connected to the corresponding first-type electrode contact 101. In other words, a sub-pixel 50 in the upper pixel layer can be electrically connected to the corresponding first-type electrode contact 101 through the interconnecting conductive component passing through the lower sub-pixel 50.

[0128] The aforementioned "peripheral light-emitting area" is the area that can emit light after being powered on. To ensure its normal light emission, the inner wall (side wall) of the peripheral light-emitting area and the interconnecting conductive components inside the channel are insulated and isolated to avoid direct contact between the non-interconnecting conductive components and 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.

[0129] 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 interconnecting conductive elements 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 1As shown in the figure, the direction of the dashed arrow indicates the light emission direction of the first layer of sub-pixels.

[0130] In some embodiments, among two sub-pixels 50 located in different pixel layers: the projection area of ​​the upper sub-pixel 50 connected by the interconnecting conductive element inside the aperture 501 on the driving backplate 10 is the first projection area, and the projection area of ​​the peripheral light-emitting area 502 outside the aperture 501 on the driving backplate 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 by the peripheral light-emitting area 502 to be directly emitted from the periphery of the upper sub-pixel connected by the interconnecting conductive element inside the aperture 501 without being blocked by it. This effectively reduces the obstruction of the light-emitting surface of the lower sub-pixel, increases the effective light-emitting area of ​​the lower sub-pixel, and facilitates the achievement of optimal light distribution effect.

[0131] 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.

[0132] In the above structure, a certain pixel layer adopts a type I pixel layer. The bottom of each sub-pixel 50 in the type I pixel layer is electrically connected to the corresponding first type electrode contact 101 through an independent conductive block 270. The conductive block 270 and the first type electrode contact 101 correspond one-to-one. This method helps to improve the bonding accuracy, thereby improving the resolution and display effect of the device.

[0133] The above structure allows the interconnecting conductive components of the upper sub-pixel to pass through the channels inside at least one lower sub-pixel and be electrically connected to the first type of electrode contact, which can effectively reduce the shading of the light-emitting surface of the lower sub-pixel, increase the effective light-emitting area of ​​the lower sub-pixel, and facilitate the achievement of the best light distribution effect.

[0134] 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 light-emitting region. This can be adapted to different application requirements and is more convenient for adjusting the light-emitting region. The above structure also facilitates the control of the position of the upper sub-pixels, allowing the upper sub-pixels to be set 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.

[0135] 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.

[0136] In this embodiment, the top conductive layers 60 of the sub-pixels 50 located in different pixel layers within the mother pixel are interconnected to form a top common polarity structure. That is, the top conductive layers 60 of each sub-pixel 50 in the top common polarity structure are electrically connected together and conduct electricity to each other.

[0137] In the aforementioned top common-pole structure, see [reference] Figure 1 The interconnecting conductive element inside the channel 501 is a non-common conductive element 80, which enables electrical connection at the bottom of the corresponding sub-pixel above. That is, 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. The non-common conductive element 80 passes through the channel 501, and the top of the non-common conductive element 80 inside the channel 501 is electrically connected to the bottom of the other sub-pixel 50 in the upper pixel layer. The bottom of the non-common conductive element 80 inside the channel 501 is electrically connected to the corresponding first type of electrode contact 101. The light emitted from the peripheral light-emitting area 502 is at least partially emitted through the periphery of the upper sub-pixel 50 electrically connected to the non-common conductive element 80 inside the channel 501.

[0138] In some implementations, the top electrode layer may be configured in the following manner: (See attached document) Figure 1 At least two sub-pixels 50 in a mother pixel share a top conductive layer 60, and the sub-pixels 50 that share a top conductive layer 60 are located in different pixel layers.

[0139] The above structure allows at least two sub-pixels 50 to share a single top conductive layer 60, simplifying the electrical connection structure and making it easier to fabricate.

[0140] To enhance current conduction capability, a metal reinforcement 190 can be provided on the shared top conductive layer 60 to make the two electrically connected.

[0141] In some embodiments, the bottom of the sub-pixel 50 in a pixel layer is further provided to be electrically connected to its respective conductive block 270 via a metal reflective layer 280.

[0142] Furthermore, the bottom end of the sub-pixel 50 in the type pixel layer is electrically connected to the electrical contact area 2701 of the corresponding conductive block 270 through the metal reflective layer 280.

[0143] Further, see Figure 1 , Figure 15 and Figure 16 This allows the sub-pixel 50 in a pixel layer to be electrically connected only at its bottom end to the metal reflective layer 280, thus exposing only the bottom end of the sub-pixel 50 to contact the metal reflective layer 280.

[0144] Or, see Figures 13-14 This makes the bottom of sub-pixel 50 in a type-1 pixel layer ( Figure 14 (at j1) and at least part of the sidewall ( Figure 14 At point j2, all sub-pixels 50 are in contact with the metal reflective layer 280 to achieve electrical connection. This exposes the bottom and part of the sidewalls of the sub-pixel 50, allowing them to contact the metal reflective layer 280. This method further increases the contact area, thereby increasing the current injection capability. It should be noted that... Figure 13 The structure shown needs to be flipped so that the substrate 310 faces upward when it is bonded to the driving backplate. Here, "bottom end of sub-pixel" refers to the end near the driving backplate.

[0145] Understandably, the aforementioned "sidewall" can be either the outer or inner sidewall of the sub-pixel 50. If the sub-pixel has a channel 501 inside, an inner sidewall will be formed; otherwise, only an outer sidewall will be formed. The exposure height of the sidewall for electrical contact should not be too large, to ensure that the sub-pixel sidewall does not short-circuit.

[0146] Further, see Figure 1 The upper part of the metal reflective layer 280 has a peripheral reflective portion 2801. The sub-pixel 50 in the type pixel layer is surrounded by the peripheral reflective portion 2801. The peripheral reflective portion 2801 and the outer sidewall of the surrounding sub-pixel 50 are insulated and isolated by a first insulating layer 150 to prevent the sub-pixel 50 from short-circuiting at the sidewall and causing leakage. This arrangement allows the metal reflective layer 280 to surround the end of the sub-pixel 50 near the driving backplate 10 and its sidewall, which can better reflect the light from the sub-pixel 50 in the X direction. This allows most of the light emitted by the sub-pixel 50 to exit from above the sub-pixel 50, which is beneficial for enhancing light efficiency.

[0147] In some embodiments, in a certain type of pixel layer: a channel 501 is formed inside a sub-pixel 50, a peripheral light-emitting area 502 is formed around the channel 501, and an inner reflective portion 2802 is also formed on the upper part of the metal reflective layer 280. The inner reflective portion 2802 is located inside the channel 501 and surrounds the periphery of the interconnecting conductive members inside the channel 501. The inner reflective portion 2802 and the inner sidewall of the peripheral light-emitting area 502 are insulated and isolated by a first insulating layer 150.

[0148] The aforementioned inner reflective portion 2802 allows light incident on the inside of the channel 501 to be reflected back through the inner reflective portion 2802, thereby better reducing light loss in the outer light-emitting area 502.

[0149] Both the outer reflective portion 2801 and the inner reflective portion 2802 can be annular.

[0150] 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.

[0151] For example, see Figure 1 The first pixel layer 20 is a type-1 pixel layer. The aforementioned channel 501 is formed inside a sub-pixel 50 in this type-1 pixel layer. The upper part of the metal reflective layer 280 has an outer reflective portion 2801 and an inner reflective portion 2802. The inner reflective portion 2802 is located inside the channel 501 of the sub-pixel 50 and surrounds the non-common conductive member 80 inside the channel 501. The outer reflective portion 2801 surrounds the periphery of the sub-pixel 50.

[0152] 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;

[0153] In some designs, the thickness of the first insulating layer 150 can be 5 nm to 2 μm.

[0154] In some implementation methods: see Figure 1 , Figure 15 In the first pixel layer 20, the bottom of the sub-pixel 50 in the first pixel layer can also be covered by the ohmic contact layer 290, so that the bottom of the sub-pixel 50 in the first pixel layer is provided with the ohmic contact layer 290 and the metal reflective layer 280 of the sub-pixel, and the electrical connection is achieved through the ohmic contact layer 290.

[0155] The aforementioned ohmic contact layer 290 is made of a conductive material.

[0156] For example, the ohmic contact layer 290 can be one or more of the following transparent conductive films: indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium tin oxide (IGZO), aluminum-doped zinc oxide (AZO), etc.; or it can be one or more of the following conductive metal materials: nickel (Ni), chromium (Cr), gold (Au), silver (Ag), zinc (Zn), rhodium (Rh), beryllium (Be), aluminum (Al); or it can be a composite structure composed of transparent metal oxide and metal. The thickness of the ohmic contact layer is 1 nm to 500 nm.

[0157] In other implementations: see Figures 11-12 In a type-1 pixel layer, the bottom of the sub-pixel 50 may not have an ohmic contact layer. Instead, the bottom of the sub-pixel 50 in the type-1 pixel layer can be made to directly contact the metal reflective layer 280 of the sub-pixel 50 to achieve electrical connection. This method allows the metal reflective layer 280 to also function as an ohmic contact.

[0158] For further details, please refer to [link / reference]. Figure 12 In one type of pixel layer, an etch stop layer 230 is also provided at the bottom of the sub-pixel 50. This etch stop layer 230 is partially retained to partially cover the bottom of the sub-pixel 50, exposing the area of ​​the sub-pixel 50 not covered by the etch stop layer 230. This exposed area then directly contacts the metal reflective layer 280 of the sub-pixel to achieve electrical connection. Alternatively, see also... Figure 11 Completely remove the etching barrier layer 230.

[0159] In some embodiments, if the top of the interconnecting conductive element inside the aperture 501 is electrically connected to the upper sub-pixel located in a type I pixel layer, then the top of the interconnecting conductive element inside the aperture 501 of the lower sub-pixel is electrically connected to the bottom of a sub-pixel in a certain type I pixel layer above through the conductive block 270, and the bottom of the interconnecting conductive element inside the aperture 501 is electrically connected to the corresponding first type electrode contact 101.

[0160] For example, such as Figure 1 In the top common electrode structure shown, the first pixel layer 20 and the second pixel layer 30 are both type I pixel layers. In the first pixel layer 20, a channel 501 is formed inside the sub-pixel 50. The top end of the non-common electrode conductive element 80 (interconnect conductive element) inside the channel 501 of the sub-pixel 50 is electrically connected to the bottom end of a sub-pixel 50 in the upper second pixel layer 30 through the conductive block 270. The bottom end of the interconnect conductive element inside the channel 501 is electrically connected to the corresponding first type electrode contact 101.

[0161] Further, see Figures 15-16The top end of the non-common conductive element 80 inside the channel 501 is electrically connected via a transition block 300 to the bottom conductive block 270 of a sub-pixel 50 in an upper type-1 pixel layer; the circumferential periphery of the transition block 300 is surrounded by an insulating medium bb. The aforementioned transition conductive block 270 can serve as an alignment reference for the upper sub-pixel, allowing the bottom conductive block 270 of the upper sub-pixel to align with the transition block 300 and be electrically connected to the non-common conductive element 80 via the transition block 300. Further, as... Figure 16 As shown, a metal reinforcement 190 may also be provided on the upper part of the top conductive layer 60.

[0162] In the aforementioned microdisplay devices, the arrangement of each pixel layer can be achieved in the following ways:

[0163] The first method: All pixel layers are type-one pixel layers. For example, see [link to relevant documentation]. Figure 1 The microdisplay device has two pixel layers, namely a first pixel layer 20 and a second pixel layer 30, both of which are type I pixel layers.

[0164] The second method: In addition to making at least one pixel layer a type I pixel layer, at least one pixel layer is also made a type II pixel layer. The bottom end of the sub-pixel 50 in the type II pixel layer is electrically connected to the corresponding first type electrode contact 101 through the bottom conductive layer 70. The bottom surface of the sub-pixel 50 in the type II pixel layer is completely covered by the bottom conductive layer 70. This method usually makes the area of ​​the bottom conductive layer 70 larger than the area of ​​the first type electrode contact 101 electrically connected to it, so that the first type electrode contact 101 and the bottom conductive layer 70 only need to make contact for conduction, without the need for alignment.

[0165] For example, see Figures 6-7 The microdisplay device has two pixel layers, namely a first pixel layer 20 and a second pixel layer 30. The first pixel layer 20 adopts a type I pixel layer, and the second pixel layer 30 adopts a type II pixel layer.

[0166] In some embodiments, at least one sub-pixel 50 in the type-two pixel layer is surrounded by a peripheral air gap, which is annular.

[0167] In some embodiments, in the sub-pixel 50 with a channel 501 in the type II pixel layer, an inner air gap is provided inside the channel 501. The inner air gap surrounds the periphery of the non-common conductive element 80 inside the channel, and the inner air gap is annular.

[0168] In some implementations, in the type-two pixel layer: the bottom conductive layer 70 at the bottom of the sub-pixel 50 can be a non-metallic conductive layer.

[0169] Alternatively, in the type II pixel layer: the bottom conductive layer 70 is a metal bonding layer, and a first peripheral metal fence 140 is formed on the upper part of the metal bonding layer. The sub-pixel 50 in the type II pixel layer is surrounded by the first peripheral metal fence 140, and there is insulation between the first peripheral metal fence 140 and the outer wall of the sub-pixel 50 it surrounds.

[0170] Specifically, a first insulating layer 150 can be covered on the outer wall of the sub-pixel 50, so that the first peripheral metal fence 140 and the outer wall of the surrounding sub-pixel 50 are insulated and isolated by the first insulating layer 150.

[0171] 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.

[0172] In this design, 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.

[0173] 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.

[0174] When the upper sub-pixel 50 and the adjacent lower sub-pixel 50 share a top conductive layer 60, see [reference] 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 top conductive layer 60; the material of the second insulating layer 160 can be the same as that of the first insulating layer 150.

[0175] 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.

[0176] For example, such as Figure 6 In the top common-polarity structure shown, the first pixel layer 20 is a type I pixel layer, and the second pixel layer 30 is a type II pixel layer. A channel 501 is formed inside the sub-pixel 50 in the first pixel layer 20. The top end of the non-common-polarity conductive element 80 (interconnect conductive element) inside the channel 501 of the sub-pixel 50 is electrically connected to the bottom conductive layer 70 at the bottom end of the sub-pixel 50 in the upper second pixel layer 30. The bottom end of the interconnect conductive element inside the channel 501 is electrically connected to the corresponding first type electrode contact 101. A first peripheral metal fence 140 is provided around the sub-pixel 50 in the second pixel layer 30.

[0177] Furthermore, in a certain type-II pixel layer: a channel 501 is formed inside a sub-pixel 50, and a peripheral light-emitting area 502 is formed around the channel 501. A first inner metal fence 130 is also formed on the upper part of the metal bonding layer. The first inner metal fence 130 is located inside the channel 501 and surrounds the interconnecting conductive parts inside the channel 501. The first inner metal fence 130 and the inner sidewall of the peripheral light-emitting area 502 are insulated from each other. For example, the first pixel layer 20 adopts a type-II pixel layer, the structure of which can be referred to. Figure 24 .

[0178] Specifically, the inner walls of the first inner metal fence 130 and the outer light-emitting area 502 are covered with a first insulating layer 150, and the first inner metal fence 130 and the inner walls of the outer light-emitting area 502 are insulated and isolated from each other by the first insulating layer 150.

[0179] The metal bonding layer at the bottom of the sub-pixel 50 with the aperture 501 and the first inner metal fence 130 can be integrally formed, or the metal bonding layer at the bottom of the sub-pixel 50 with the aperture 501 and the first inner metal fence 130 can be separately arranged.

[0180] For example, the first pixel layer 20 is a type II pixel layer. The aforementioned channel 501 is formed inside a sub-pixel 50 in the type II pixel layer. A first peripheral metal fence 140 and a first inner metal fence 130 are formed on the upper part of the metal bonding layer. The first inner metal fence 130 is located inside the channel 501 of the sub-pixel 50 and surrounds the periphery of the non-common conductive member 80 (interconnect conductive member) inside the channel 501. The first inner metal fence 130 surrounds the periphery of the sub-pixel 50.

[0181] In some implementations, when there is no metal bonding layer at the bottom of the sub-pixel, the aforementioned first inner metal fence 130 and first outer metal fence 140 may also be provided.

[0182] In some implementations, such as Figure 1 and Figure 2 As shown, the sub-pixel 50 with the aperture 501 and any upper sub-pixel 50 connected to the non-common conductive element 80 (interconnect conductive element) inside the aperture 501 are all coaxially arranged (the axes coincide); wherein Figure 1 It can be Figure 2 A sectional view of the central structure along point AA; it should be noted that... Figure 2 The image only roughly illustrates the distribution of each sub-pixel and electrode contact. The size of the sub-pixels is shown using equal-diameter sub-pixels. If the sub-pixels are like... Figure 1As shown, the component is shaped with a larger diameter at the top and a smaller diameter at the bottom. The average of its maximum and minimum diameters can be used. Similarly, when the non-common conductive component 80 is shaped with a smaller diameter at the top and a larger diameter at the bottom, the average of its maximum and minimum diameters can also be used. Figure 2 In the first pixel layer 20, sub-pixel 50 is denoted as i1, and the first type of electrode contact 101 connected to it is denoted as c1. In the second pixel layer 30, sub-pixel 50 is denoted as i2, and the first type of electrode contact 101 connected to it is denoted as c2.

[0183] Alternatively, the sub-pixel 50 with aperture 501 and the sub-pixel 50 located above it connected to the non-common conductive element 80 (interconnect conductive element) within aperture 501 are arranged on opposite axes (the axes do not coincide).

[0184] In some embodiments, the projection of the sub-pixel 50 located above the non-common conductive element 80 inside the aperture 501 onto the driving backplate 10 is the first projection area, and the projection area of ​​the sub-pixel 50 with the aperture 501 onto the driving backplate 10 is the third projection area. The first projection area can completely fall inside the third projection area. In this case, the area of ​​the first projection area can be made smaller than the area of ​​the third projection area. For example, the width (or outer diameter) of the sub-pixel 50 with the aperture 501 along the X direction can be made larger than the width (or outer diameter) of the sub-pixel 50 located above the non-common conductive element 80 inside the aperture 501 along the X direction, so as to better ensure the light emission effect.

[0185] 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.

[0186] The shape of each sub-pixel 50 is not limited; it can be a circle, ellipse, polygon (triangle, trapezoid, rectangle, etc.) or other shapes.

[0187] In some embodiments, the interconnecting conductive elements inside the aperture 501 can penetrate multiple sub-pixels 50 of different pixel layers, and each of the penetrated sub-pixels 50 is provided with an aperture 501 through which the corresponding interconnecting conductive elements pass.

[0188] The materials of the aforementioned interconnecting conductive components can be metals such as aluminum (Al), copper (Cu), and tungsten (W), as well as their corresponding adhesive or barrier layers, such as titanium (Ti), titanium nitride (TiN), tantalum nitride / copper (Ti / Cu), tantalum nitride / copper (TaN / Cu), etc.

[0189] In some embodiments, in a sub-pixel 50 having a channel 501 in a pixel layer: one or more independent conductive blocks 270 may be provided at the bottom end of the sub-pixel 50 having a channel 501.

[0190] For example, see Figure 3 The mother pixel has two sub-pixels 50, which are coaxially arranged. At this time, two independent conductive blocks 270 are set at the bottom of the sub-pixels 50 in the first pixel layer, and two first-type electrode contacts 101 are electrically connected to them; or, see [link to relevant documentation]. Figure 4 At this point, only one independent conductive block 270 is provided at the bottom of the sub-pixel 50 in the first pixel layer, and there is also one first-type electrode contact 101 electrically connected to it. The aforementioned conductive blocks 270 are all located below the peripheral light-emitting area 502.

[0191] In some implementations, the maximum width (or outer diameter) 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 interconnecting conductive element inside 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.

[0192] In some embodiments, a second type of electrode contact (not shown in the figure) may also be provided on the drive back plate 10, and the polarities of the first type of electrode contact 101 and the second type of electrode contact are opposite; the bottom end of each of the multiple sub-pixels 50 in the mother pixel is electrically connected to the corresponding first type of electrode contact 101 through the bottom conductive layer 70, and the top ends of the multiple sub-pixels 50 are electrically connected to the second type of electrode contact (not shown in the figure) through the top conductive layer 60 to form a top common electrode structure.

[0193] The driving backplate 10 is divided into display areas, and all the mother pixels form a pixel array. The projection of the pixel array onto the driving backplate 10 is located inside the display area, which means that the display area is the area where the pixel array projection is located.

[0194] The second type of electrode contacts can be set up in the following ways:

[0195] The first method involves setting the second type of electrode contacts only inside the display area. For example, the second type of electrode contacts can be set within the local display area where each mother pixel is projected.

[0196] The second method involves setting the second type of electrode contacts only on the periphery of the display area. For example, a peripheral electrode contact area is provided on the periphery of the display area, and the second type of electrode contacts can be set within the peripheral electrode contact area; an interface is also provided on the periphery of the display area, and the peripheral electrode contact area can be electrically connected to the interface.

[0197] The third type: Type II electrode contacts are set both outside and inside the display area.

[0198] In some embodiments, the microdisplay device further includes a common electrode contact 90, through which second type electrode contacts are electrically connected to a top conductive layer 60 at the top of a plurality of sub-pixels 50 to achieve top common electrode.

[0199] Furthermore, the top conductive layers 60 of multiple sub-pixels in the mother pixel are all connected to the second type of electrode contact via a common conductive element, see [reference]. Figure 20 , Figure 30 and Figure 31 The bottom end of the common electrode 90 is in direct contact with the corresponding second type electrode contact. In some embodiments, multiple mother pixels can share a single second type electrode contact, or each mother pixel can independently use its own corresponding second type electrode contact.

[0200] In this embodiment, the interconnecting conductive components pass through the channel 501. A first insulating filling area is provided inside the channel, and the interconnecting conductive components inside the channel directly pass through the first insulating filling area. For example... Figure 1 As shown, a first insulating filling area 100 is provided inside the channel 501, and the interconnecting conductive element is a non-common conductive element 80. The non-common conductive element 80 directly passes through the first insulating filling area 100 and is electrically connected to the corresponding first type of electrode contact 101.

[0201] In some embodiments, a second insulating fill area 110 is further provided around the sub-pixel 50 in the type pixel layer.

[0202] Further, see Figure 1 In the mother pixel, the sub-pixels 50 in two adjacent pixel layers share a top conductive layer 60. The upper pixel layer in the two adjacent pixel layers is a type I pixel layer. At this time, the shared top conductive layer 60 passes through the second insulating filling area 110 in the upper pixel layer.

[0203] In some implementations, at least two sub-pixels in a mother pixel located in different pixel layers emit different colors. For example, in a two-layer structure with two pixel layers, the sub-pixels in each pixel layer may emit the same color, while the sub-pixels in different pixel layers emit different colors. 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.

[0204] In some implementations, the sub-pixels 50 in different pixel layers of the multi-layer stacked structure emit different colors to achieve a color configuration.

[0205] 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.

[0206] In this embodiment, each sub-pixel 50 can be made of inorganic compound semiconductor material.

[0207] In some implementations, see Figures 3-4 A lens 250 is provided above the uppermost sub-pixel 50, and the lens 250 covers at least one sub-pixel 50 in the parent pixel. For example, one lens 250 can cover one sub-pixel 50, or it can cover multiple sub-pixels 50.

[0208] In this embodiment, both the first insulating filling area 100 and the second insulating filling area 110 can be made of transparent filling material.

[0209] 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 is as follows: Figure 1 Each pixel layer in the process is a type I pixel layer, and the method includes the following steps:

[0210] Step S1: Provide a drive backplate 10, on which a first type of electrode contact 101 is provided;

[0211] 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, such that the N-type semiconductor layer is located at the end away from the driving backplate 10 and the P-type semiconductor layer is located at the end close to the driving backplate 10.

[0212] Step S2: The pixel layer is processed to obtain sub-pixels 50, and two pixel layers are stacked sequentially from bottom to top above the driving backplate 10. Sub-pixels 50 are prepared in each pixel layer, so that each parent pixel includes two sub-pixels 50. Sub-pixels with different emission colors 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 sequentially from top to bottom.

[0213] This ensures that the bottom of each sub-pixel 50 located in different pixel layers of the mother pixel is electrically connected to the corresponding first type of electrode contact 101; the tops of multiple sub-pixels 50 are electrically connected to the corresponding top conductive layer 60, and the top conductive layers 60 are interconnected to form a top common electrode structure.

[0214] And both pixel layers are type I pixel layers, and the bottom of each sub-pixel 50 in the type I pixel layer is electrically connected to the corresponding first type electrode contact 101 through an independent conductive block 270. The conductive block 270 and the first type electrode contact 101 correspond one-to-one.

[0215] In this embodiment, among the two sub-pixels 50 located in different pixel layers, one of the sub-pixels 50 in the lower pixel layer has an opening 501 inside, and an outer light-emitting area 502 is formed around the opening 501. An interconnecting conductive component passes through the opening 501, and the top end of the interconnecting conductive component inside the opening 501 is electrically connected to the bottom end of the other sub-pixel 50 in the upper pixel layer. The bottom end of the interconnecting conductive component inside the opening 501 is electrically connected to the corresponding first type of electrode contact 101. At least part of the light emitted from the outer light-emitting area 502 is emitted through the outer periphery of the upper sub-pixel 50 electrically connected to the interconnecting conductive component inside the opening 501.

[0216] Step S2, which involves stacking two pixel layers sequentially from bottom to top (Z direction) on the driving backplane 10, may specifically include the following steps (see...). Figure 10 ):

[0217] Step S201: Refer to Figure 10 In stage b1, the first pixel layer 20 is a type I pixel layer. The preparation of this type I pixel layer is carried out first. During preparation, a compound semiconductor layer is selected as the type I pixel layer. The compound semiconductor layer is etched to obtain sub-pixels 50, and independent conductive blocks 270 are prepared so that the end of the sub-pixel 50 in the type I pixel layer that is close to the driving back plate 10 is electrically connected to the corresponding conductive block 270. At the same time, a channel 501 is opened inside the sub-pixel 50 in the current pixel layer and a non-common conductive component 80 (i.e., an interconnect conductive component) is prepared.

[0218] In specific preparation:

[0219] Step S2011: First refer to Figure 10 In stage b1, a compound semiconductor layer is selected as the current pixel layer. This pixel layer is disposed on the substrate. The current pixel layer is etched to obtain sub-pixel 50, so as to realize 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 along the Z direction. The N-type semiconductor layer can be located at the end closer to the substrate and the P-type semiconductor layer is located at the end farther away from the substrate.

[0220] 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.

[0221] When etching the current pixel layer (compound semiconductor layer) to obtain sub-pixel 50, the corresponding sub-pixel 50 is also subjected to aperture processing, so that a channel 501 is formed inside the sub-pixel 50, and the compound semiconductor region around the channel 501 forms the peripheral light-emitting region.

[0222] Step S2012: Deposit a first insulating layer 150 on the surface of the current pixel layer, such that the first insulating layer 150 covers the top surface, outer sidewall and inner wall of the aperture 501 of the sub-pixel 50;

[0223] 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;

[0224] Step S2013: Remove at least a portion of the first insulating layer 150 at the end of the sub-pixel 50 away from the substrate 310, so that the end of the sub-pixel 50 away from the substrate 310 is exposed, and deposit a metal reflective layer 280 on the outside of the sub-pixel 50, so that the metal reflective layer 280 contacts the exposed area of ​​the sub-pixel 50 to achieve electrical connection.

[0225] In some embodiments, before etching the pixel layer, an etching barrier layer 230 is formed at the end of the pixel layer away from the substrate 310 to serve as an etching mask. The etching barrier layer 230 can be a transparent material. The etching barrier layer 230 can also be an insulating medium.

[0226] When the metal reflective layer 280 contacts the exposed area of ​​the sub-pixel 50 to achieve electrical connection, the etch barrier layer 230 can be completely removed, and part of the first insulating layer 150 can be removed so that the end of the sub-pixel away from the substrate 310 is exposed and the exposed area contacts the metal reflective layer 280 to achieve electrical connection; or, part of the etch barrier layer 230 can be retained, and part of the etch barrier layer 230 and part of the first insulating layer 150 can be removed so that the end of the sub-pixel away from the substrate 310 is exposed and the exposed area contacts the metal reflective layer 280 to achieve electrical connection.

[0227] Specifically, when depositing the metal reflective layer 280 on the outside of the sub-pixel 50, the metal reflective layer 280 can be disposed around the end of the sub-pixel away from the substrate 310 and its sidewalls (inner and outer sidewalls). The section of the metal reflective layer 280 located at the end of the sub-pixel away from the substrate 310 is in contact with the exposed area of ​​the sub-pixel 50 to achieve electrical connection. The section of the metal reflective layer 280 located at the outer sidewall of the sub-pixel 50 forms a peripheral reflective portion 2801 and surrounds the periphery of the sub-pixel 50. The peripheral reflective portion 2801 and the surrounding outer sidewall of the sub-pixel 50 are insulated and isolated by the first insulating layer 150. In addition, the section of the metal reflective layer 280 located at the inner sidewall of the sub-pixel 50 forms an inner reflective portion 2802. The inner reflective portion 2802 is located inside the channel 501. The inner reflective portion 2802 and the inner sidewall of the peripheral light-emitting area 502 are insulated and isolated by the first insulating layer 150.

[0228] Step S2014: Fill the periphery of the sub-pixel 50 with the aperture treatment and the interior of the aperture 501 with an insulating medium, thereby forming a first insulating filling region 100 inside the aperture 501 and a second insulating filling region 110 around the sub-pixel 50. At the same time, the filling height of the insulating medium is higher than that of the sub-pixel 50, so that the end of the sub-pixel 50 away from the substrate 310 also has an insulating medium.

[0229] For example, the filling medium used in the first insulating filling region 100 and the second insulating filling region 110 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.

[0230] Step S2015: Fabrication of conductive block 270 and non-common conductive element 80 (interconnect conductive element). Conductive block 270 is obtained by forming a filling hole in the insulating medium at the end of the sub-image away from the substrate 310 and filling the filling hole with conductive material, so that the metal reflective layer 280 of the sub-pixel 50 in the type pixel layer contacts the corresponding conductive block 270 to achieve electrical connection; and non-common conductive element 80 is obtained by forming a filling hole in the first insulating filling region 100 and filling the filling hole with conductive material.

[0231] Step S202: See Figure 10 In stage b2, after the preparation of the first pixel layer 20 is completed in step 201, the prepared first pixel layer 20 is bonded to the driving backplate 10 to achieve bonding integration. At this time, the first pixel layer is flipped so that its substrate 310 is on top. After bonding, the bottom ends of the sub-pixels 50 in the pixel layer are electrically connected to the corresponding first type electrode contact 101 through independent conductive blocks 270. The conductive blocks 270 and the first type electrode contact 101 correspond one-to-one.

[0232] Understandable, please refer to Figure 10 In the middle b3 stage, after bonding is completed, the substrate 310 needs to be removed. Removing the substrate 310 exposes the top of the sub-pixel 50 so that it can contact the subsequent top conductive layer 60 to achieve top electrical connection.

[0233] After removing the substrate 310, the thickness of the sub-pixel 50 (the distance between the upper surface of the N-type semiconductor layer and the lower surface of the P-type semiconductor layer) is 0.1um to 5um.

[0234] In some embodiments, after removing the substrate 310, see [reference] Figures 15-16 Furthermore, an insulating dielectric bb can be deposited on top of the first pixel layer 20, and a filling hole can be formed in the insulating dielectric bb and filled with conductive material to form a transition block 300. The transition block 300 is in contact with the non-common conductive element 80 inside the channel 501 of the sub-pixel 50 in the first pixel layer 20. The aforementioned transition conductive block 270 can serve as an alignment reference for the upper sub-pixel 50 in the next step, so that the conductive block 270 at the bottom of the upper sub-pixel 50 is aligned with the transition block 300 and electrically connected to the non-common conductive element 80 through the transition block 300.

[0235] Step S202: See Figure 10 In the middle b4 stage, the second pixel layer 30 is prepared, and the second pixel layer 30 also adopts a type I pixel layer;

[0236] The prepared second pixel layer 30 is bonded to the first pixel layer 20 to achieve bonding integration. After bonding, the bottom ends of the sub-pixels 50 in the pixel layer are electrically connected to the corresponding first type electrode contact 101 through independent conductive blocks 270. The conductive blocks 270 and the first type electrode contact 101 correspond one-to-one.

[0237] Specifically, the bottom end of the sub-pixel 50 in the second pixel layer 30 is connected to the non-common conductive member 80 below through an independent conductive block 270, and is electrically connected to the corresponding first type electrode contact 101 through the non-common conductive member 80 to achieve electrical connection.

[0238] The fabrication method of the second pixel layer 30 is roughly the same as that of the first pixel layer 20, and will not be described in detail here. However, the sub-pixel 50 in the second pixel layer 30 may not have a hole 501 inside.

[0239] Step S203: Connect the electrode at the top of sub-pixel 50: See Figure 10In the middle b5 stage, the tops of sub-pixels 50 in the second pixel layer 30 and sub-pixels 50 in the first pixel layer 20 are exposed. Then, a top conductive layer 60 is deposited or plated so that the tops of sub-pixels 50 in the second pixel layer 30 and sub-pixels 50 in the first pixel layer 20 are in contact with the top conductive layer 60 to achieve electrical connection. In the structure prepared at this time, sub-pixels 50 in the second pixel layer 30 and sub-pixels 50 in the first pixel layer 20 share a top conductive layer 60.

[0240] 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 the sub-pixel can be removed by etching.

[0241] 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.

[0242] Furthermore, the periphery of the sub-pixel 50 in the second pixel layer 30 is provided with a second insulating filling area 110 for the preparation of the aforementioned common top conductive layer 60. At this time, it is necessary to open a hole in the second insulating filling area 110 of the second pixel layer 30 so that the top conductive layer 60 can contact the top of the sub-pixel 50 in the first pixel layer 20.

[0243] The microdisplay device obtained by the above preparation method has two pixel layers, both of which are type I pixel layers;

[0244] In other methods, one pixel layer can be a type I pixel layer and another pixel layer can be a type II pixel layer. When preparing the type II pixel layer, the type II pixel layer can first be bonded to the adjacent pixel layer below or the driving backplate 10 through a metal bonding layer. After bonding, the type II pixel layer is etched to obtain the corresponding sub-pixel 50.

[0245] For example, the microdisplay device has two pixel layers, namely a first pixel layer 20 and a second pixel layer 30, wherein, see reference Figure 29 The first pixel layer 20 is a type II pixel layer, and the second pixel layer 30 is a type I pixel layer; or, see [link to relevant documentation]. Figures 6-7 The first pixel layer 20 is a type I pixel layer, and the second pixel layer 30 is a type II pixel layer;

[0246] After completing step S203, lens 250 can be fabricated. The fabricated structure is shown in [reference needed]. Figure 3or Figure 4 .

[0247] 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.).

[0248] 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.

[0249] 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.

[0250] 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, and helps to achieve the best light distribution effect, so that its light pattern meets the needs of different application scenarios. At the same time, it also effectively improves the luminous efficiency and reliability of the display device.

[0251] Example 2

[0252] like Figures 8-9 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. At this time, the structure is a three-layer structure. The mother pixel has three sub-pixels 50. The three pixel layers are, from bottom to top, the first pixel layer 20, the second pixel layer 30, and the third pixel layer 40.

[0253] The bottom of each of the three sub-pixels 50 is electrically connected to the corresponding first type electrode contact 101, and the top of the three sub-pixels is electrically connected to the second type electrode contact through the top conductive layer 60 to form a top common electrode structure.

[0254] In this process, at least two sub-pixels 50 in the mother pixel share a top conductive layer 60, and the sub-pixels 50 that share a top conductive layer 60 are located in different pixel layers.

[0255] For example, the sub-pixels 50 in the first pixel layer 20 can have a separate top conductive layer 60, while the sub-pixels 50 in the second pixel layer 30 and the third pixel layer 40 can share a single top conductive layer 60. The two top conductive layers 60 can be interconnected by a common conductive element 90. Alternatively, the sub-pixels 50 in all three pixel layers can share a single top conductive layer 60.

[0256] Understandably, in the three-layer structure, the non-common conductive component 80 of the third sub-pixel 50 is divided into two segments, one segment is located in the second pixel layer 30, and the other segment is located in the first pixel layer 20. These two segments are prepared in two separate processes, with each end being obtained by opening a hole in the corresponding pixel layer and backfilling it with metal.

[0257] A lens 250 can also be placed above the third pixel layer 40; see reference for details. Figures 8-9 .

[0258] In some ways, see Figure 9 In a microdisplay device, all three pixel layers can be of type I pixel layer.

[0259] In other methods, it is possible to ensure that at least one pixel layer uses a type I pixel layer while allowing other pixel layers to use a type II pixel layer.

[0260] For example, see Figure 8 The microdisplay device has three pixel layers: a first pixel layer 20, a second pixel layer 30, and a third pixel layer 40. The first pixel layer 20 and the second pixel layer 30 are both type I pixel layers, while the third pixel layer 40 is a type II pixel layer. Alternatively, see [link to relevant documentation]. Figure 9 The first pixel layer 20, the second pixel layer 30, and the third pixel layer 40 are all type I pixel layers.

[0261] In some embodiments, the sub-pixel 50 with the aperture and any upper sub-pixel 50 connected to the non-common conductive element 80 inside the aperture are coaxially arranged; for example, the mother pixel has three sub-pixels 50, see [reference]. Figure 8 The bottommost sub-pixel 50 has a hole 501, and this sub-pixel is coaxially arranged with the sub-pixels of the second and third layers.

[0262] Alternatively, the sub-pixel 50 with the aperture is arranged off-axis with at least one upper sub-pixel 50 connected to the non-common conductive element 80 inside the aperture.

[0263] In some methods, the non-common conductive element 80 inside the channel 501 may penetrate only one sub-pixel 50 in a pixel layer, or it may penetrate multiple sub-pixels 50 in different pixel layers.

[0264] For example, when making specific settings, refer to Figure 8The non-common conductive element 80 of the sub-pixel 50 in the third pixel layer 40 passes through the sub-pixels 50 in the second pixel layer 30 and the first pixel layer 20 and is electrically connected to the first type of electrode contact 101. The sub-pixels 50 in the second pixel layer 30 and the first pixel layer 20 are provided with a channel 501 for the non-common conductive element 80 to pass through. That is, the non-common conductive element 80 of the upper sub-pixel not only passes through the lowermost sub-pixel, but also passes through at least one sub-pixel between the lowermost sub-pixel and the uppermost sub-pixel.

[0265] Alternatively, the non-common conductive element 80 of the sub-pixel 50 in the third pixel layer 40 only penetrates the sub-pixel 50 in the first pixel layer 20, but not the sub-pixel 50 in the second pixel layer 30, and the non-common conductive element 80 of the sub-pixel 50 in the second pixel layer 30 only penetrates 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 for the non-common conductive element 80 to pass through; that is, the non-common conductive element 80 of the upper sub-pixel only penetrates the lowermost sub-pixel, but not the other sub-pixels in the middle layer.

[0266] Alternatively, the non-common conductive element 80 of the sub-pixel 50 in the third pixel layer 40 can 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 outer region of the corresponding sub-pixel in the first layer, and finally connect to the corresponding first type of electrode contact 101.

[0267] The shape of each sub-pixel is not limited; it can be a circle, trapezoid, rectangle, or other shapes.

[0268] In some implementations, the same channel 501 of the lower sub-pixel 50 can be penetrated by non-common conductive elements 80 of multiple sub-pixels 50 in different upper pixel layers. For example, a channel 501 is provided inside a sub-pixel 50 in the first pixel layer 20, and the non-common conductive elements 80 at the bottom of the sub-pixels 50 in the second pixel layer 30 and the third pixel layer 40 both pass through the same channel 501 in the first pixel layer 20.

[0269] In some implementations, at least two subpixels located in different pixel layers emit different colors.

[0270] For example, in a three-layer structure, the sub-pixels 50 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 50 from bottom to top are red, green, and blue, respectively.

[0271] Example 3

[0272] In this embodiment, the interior of the channel 501 is for interconnecting conductive components to pass through, and the interconnecting conductive components can be installed in the following ways:

[0273] The first type: A first insulating filling area is provided inside the channel 501, and the interconnecting conductive components inside the channel 501 directly pass through the first insulating filling area. For example... Figure 1 As shown, a first insulating filling area 100 is provided inside the channel 501, and the interconnecting conductive element is a non-common conductive element 80. The non-common conductive element 80 directly passes through the first insulating filling area 100 and is electrically connected to the corresponding first type of electrode contact 101.

[0274] When the first structure described above is prepared, the following preparation 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 non-common conductive element 80 directly passes through the first insulating filling area 100 and is electrically connected to the first type of electrode contact 101.

[0275] 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.

[0276] The second method involves a compound semiconductor region within the channel 501, through which interconnecting conductive components pass. This method retains more compound semiconductor material, which has good thermal conductivity, thus improving the overall heat dissipation of the device.

[0277] Understandably, the compound semiconductor region penetrated by the interconnecting conductive components does not emit light when an electric current is applied.

[0278] The second structure described above can be fabricated using the following method: a portion of the compound semiconductor material is retained inside the channel 501 to form a compound semiconductor region, allowing the interconnecting conductive components to pass through the compound semiconductor region and be electrically connected to the first type of electrode contacts.

[0279] Example 4

[0280] In this embodiment, the top ends of the sub-pixels 50 located in different pixel layers within the mother pixel are all electrically connected to the corresponding top conductive layer 60, and the bottom ends of the sub-pixels 50 are each electrically connected to the corresponding first type of electrode contact 101; the top electrode layer can be configured in the following manner:

[0281] The first method: At least one sub-pixel 50 in the mother pixel has a separate top conductive layer 60 at its top, which is not shared with other sub-pixels 50 in different pixel layers. The fabrication method of the pixel layer where this sub-pixel 50 is located can be found in [reference needed]. Figures 15-28Understandably, the pixel layer containing sub-pixel 50 can be a type I pixel layer (see [reference]). Figures 15-20 Alternatively, a type II pixel layer can be used (see [link]). Figures 24-28 )

[0282] In some schemes, the top of each sub-pixel in a different pixel layer of the mother pixel is provided with a separate top conductive layer 60 instead of sharing it; that is, the top of each sub-pixel in a different pixel layer of the mother pixel is provided with a separate top conductive layer 60 instead of sharing it, and they can be interconnected with each other through a common conductive component.

[0283] Furthermore, the top conductive layer (the top conductive layer electrically connected to the sub-pixel in the same pixel layer) is 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. 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 15 In the first pixel layer, the entire top conductive layer 60 of the sub-pixel is located above the sub-pixel 50, or, see [link to relevant documentation]. Figure 28 In the first pixel layer, the top conductive layer 60 of the sub-pixel is basically located above the sub-pixel 50, with only the top conductive layer area on the outer periphery of the sub-pixel sidewall being slightly lower.

[0284] For example, see Figures 21-23 In the first pixel layer 20, a top conductive layer 60 is separately provided at the top of the sub-pixel 50, and in the second pixel layer 30, a top conductive layer 60 is also separately provided at the top of the sub-pixel 50. The top electrode layers in the first pixel layer 20 and the second pixel layer 30 are interconnected by the interconnecting conductive part 901 of the common conductive member 90.

[0285] When a top conductive layer 60 is separately disposed at the top of the sub-pixel 50 in the first pixel layer 20, the following fabrication method can be adopted: After the first pixel layer 20 is bonded to the driving backplane 10, the sub-pixel is etched in the first pixel layer 20, and then an insulating medium is backfilled in the current pixel layer. After backfilling, the top of the first pixel layer 20 is planarized to expose the top of the sub-pixel 50 in the pixel layer. Then, the top conductive layer 60 is deposited so that it contacts the exposed area at the top of the sub-pixel 50 to achieve electrical connection. Then, an insulating medium can be deposited again on the top of the pixel layer and planarized again, and then the upper pixel layer is stacked. The top conductive layer 60 of the upper pixel layer can be fabricated separately in the same way, that is, after etching the sub-pixel, an insulating medium is backfilled. After backfilling, the top of the pixel layer is planarized to expose the top of the sub-pixel in the pixel layer, and then the top conductive layer 60 is deposited to achieve electrical connection.

[0286] The above-described preparation method also ensures that in a sub-pixel with a separate top conductive layer, the top conductive layer of the sub-pixel is basically located at the top of the sub-pixel.

[0287] In some implementations, the second type of electrode contacts are electrically connected to the top conductive layer 60 at the top of a plurality of sub-pixels via a common conductor 90.

[0288] In some implementations, see Figure 20 , Figure 30 , Figure 31 The bottom end of the common electrode 90 is in direct contact with the corresponding second type of electrode contact.

[0289] Each sub-pixel located in a different pixel layer in the mother pixel has a separate top conductive layer 60 at its top and they do not share a common conductive layer; the common conductive component 90 includes an interconnect conductive part 901, and two adjacent top conductive layers 60 are interconnected through the interconnect conductive part 901 to achieve electrical connection;

[0290] Among them, see Figure 17 and Figure 26 An electrical connection is achieved by direct contact between a top conductive layer 60 and the electrically connected interconnect conductive part 901;

[0291] Alternatively, to enhance current conduction capability, see [reference needed]. Figure 21 A top conductive layer 60 is electrically connected to a metal reinforcement; further, see [reference needed]. Figure 18 and Figure 27 A top conductive layer 60 is electrically connected to an interconnected conductive portion 901 via a metal reinforcement 190.

[0292] Furthermore, the sub-pixel 50 is in contact only at its top tip with the electrically connected top conductive layer 60, 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. The pixel layer in which the aforementioned sub-pixel is located can be a type I pixel layer or a type II pixel layer.

[0293] For example, referring to 24, the top of the sub-pixel 50 in the first pixel layer 20 can be fully exposed, and the exposed area can be in contact with the top conductive layer 60 to achieve electrical connection; or, referring to Figure 28 This allows the top and part of the sidewalls of the sub-pixel 50 in the first pixel layer 20 to be exposed, and the exposed area to contact the top conductive layer 60 to achieve electrical connection, thereby increasing the current transmission capability and reducing the power consumption of the device.

[0294] In some designs, at least one top conductive layer 60 is electrically connected to the metal reinforcement 190 to enhance current conduction.

[0295] The metal reinforcement 190 can be installed in the following ways:

[0296] One is: See Figure 16 and Figure 25 The metal reinforcement 190 is located above the electrically connected top conductive layer 60.

[0297] Another option is: See Figure 19 The metal reinforcement 190 is located below the electrically connected top conductive layer 60; further, the metal reinforcement 190 surrounds the periphery of a sub-pixel 50 below the electrically connected top conductive layer 60.

[0298] Furthermore, the bottom of the metal reinforcement 190 is not lower than the top of the surrounding sub-pixel 50.

[0299] In some implementations, the metal reinforcement 190 in different mother pixels can be shared or used independently by their respective mother pixels.

[0300] The second method: Refer to Figure 1 At least two sub-pixels 50 in a mother pixel share a top conductive layer 60, and the sub-pixels that share a top conductive layer 60 are located in different pixel layers.

[0301] The above structure allows at least two sub-pixels 50 to share a single top conductive layer 60, simplifying the electrical connection structure and making it easier to fabricate.

[0302] In some implementations, such as Figure 30 As shown, the common conductive element 90 is in direct contact with the common top conductive layer 60 to achieve electrical connection;

[0303] Or, such as Figure 31 As shown, the common conductive element 90 is electrically connected to the common top conductive layer via the transition conductive element 200. For example, in Figure 31 In the structure shown, the upper and lower sub-pixels 50 share a top conductive layer 60, which is connected to the lower common electrode conductive element 90 through a transition conductive element 200.

[0304] Furthermore, a sub-pixel 50 may be made to have only its top end in contact with the electrically connected top conductive layer 60, or the top end and at least part of the sidewalls of the sub-pixel 50 may be in contact with the electrically connected top conductive layer 60.

[0305] To enhance current conduction capability, a metal reinforcement 190 can be provided on the shared top conductive layer 60 to make the two electrically connected.

[0306] The aforementioned metal reinforcement 190 can be installed in the following ways:

[0307] One is: See Figure 5 The metal reinforcement 190 is located above the common top conductive layer 60.

[0308] Another option is: See Figure 7 The metal reinforcement 190 is located below the common top conductive layer 60; further, the metal reinforcement 190 surrounds the periphery of a sub-pixel 50 below the common top conductive layer 60.

[0309] Furthermore, the bottom of the metal reinforcement 190 is not lower than the top of the surrounding sub-pixel 50.

[0310] In the specific fabrication process, when the metal reinforcement 190 is located below the common top conductive layer 60, the metal reinforcement 190 can be inserted into the second insulating filling area 110 surrounding the lower sub-pixel 50.

[0311] In some implementations, the metal reinforcement 190 in different mother pixels can be shared or used independently by their respective mother pixels.

[0312] In this embodiment, the top of the sub-pixel 50 contacts the top conductive layer 60 to achieve electrical connection. The various configurations of the top conductive layer 60 can all employ the following electrical connection methods: First, only the top of the sub-pixel 50 contacts the electrically connected top conductive layer 60; in this case, only a portion or all of the top of the sub-pixel is exposed, and the exposed area contacts the corresponding top conductive layer 60 to achieve electrical connection. Second, the top of the sub-pixel 50 and at least a portion of its sidewalls are also in contact with the electrically connected top conductive layer 60; in this case, in addition to the top of the sub-pixel 50 being exposed, at least a portion of its sidewalls are also exposed, thus forming an exposed area that contacts the corresponding top conductive layer 60 to achieve electrical connection. This method increases the electrical contact area, facilitates current expansion, and enhances current conduction capability.

[0313] Understandably, in specific settings, the way the top of the sub-pixel 50 contacts the top conductive layer 60 can be flexibly selected. For example, one sub-pixel 50 in the mother pixel can use the first electrical connection method, while other sub-pixels can use the second electrical connection method. Alternatively, all sub-pixels 50 can use the same electrical connection method. The specific choice can be made according to actual needs.

[0314] Whether the top electrode layer is shared can be selected according to actual needs. For example, a microdisplay device has three pixel layers, all of which are stacked sequentially from bottom to top above the driving backplane. In this case, the structure is a three-layer structure, with the mother pixel having three sub-pixels 50. The three pixel layers are, from bottom to top, the first pixel layer 20, the second pixel layer 30, and the third pixel layer 40. When setting up, the top of the sub-pixel 50 in the first pixel layer 20 can be provided with a separate top conductive layer 60, while the sub-pixels 50 in the second pixel layer 30 and the third pixel layer 40 share a top conductive layer 60. The two top conductive layers 60 can be interconnected through a common electrode conductive element 90; or, the sub-pixels 50 in the three pixel layers can share a top conductive layer 60.

[0315] Example 5

[0316] See Figures 32-33 The main difference between this embodiment and Embodiment 1 is that a color transfer layer 320 is also provided above the first pixel layer 20.

[0317] 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 320 is also provided above the first pixel layer 20. The color conversion layer 320 is located on the light emission path of the corresponding sub-pixel 50 in the first pixel layer 20 to realize the conversion of the emitted light color of the sub-pixel 50.

[0318] In the above structure, the sub-pixel 50 corresponding to the light emission color conversion of the color conversion layer 320 can be a sub-pixel 50 with an aperture 501 or a sub-pixel 50 without an aperture 501.

[0319] The color conversion layer 320 can be used to change the color of emitted light. For example, if the emitted light color of a sub-pixel is blue, a color conversion layer is set on the light path of the blue sub-pixel. When the light emitted by the blue sub-pixel hits the color conversion layer, the color conversion layer 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.

[0320] The color-transfer layer 320 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.

[0321] 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.

[0322] 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.

[0323] In some implementations, the color transfer layer 320 is located above the top conductive layer 60 of the corresponding sub-pixel 50 in the first pixel layer 20.

[0324] In some schemes, see Figure 32 Sub-pixels 50 in different pixel layers share a top conductive layer 60, and a color transfer layer 320 can be set on the upper surface of the shared top conductive layer 60.

[0325] In other options, see Figure 33 In this embodiment, each sub-pixel 50 located in a different pixel layer within the parent pixel has its own separate top conductive layer 60, which is not shared. Furthermore, the top conductive layers 60 of the same pixel layer (those electrically connected to the sub-pixels in the same pixel layer) are all located above the electrically connected sub-pixels. A color transfer layer 320 can be disposed on the upper surface of the uppermost top conductive layer. In some embodiments, the microdisplay device has two pixel layers, at least one of which is a type-one pixel layer. The color transfer layer is located above the corresponding sub-pixel in the lower pixel layer of the two pixel layers.

[0326] Specifically, the microdisplay device has two pixel layers. The lower pixel layer is a type I pixel layer, and the color conversion layer 320 is located above the corresponding sub-pixel 50 in the type I pixel layer.

[0327] For example, see Figure 32 The microdisplay device has two pixel layers, namely a first pixel layer 20 and a second pixel layer 30. The sub-pixels of the first and second layers share a top conductive layer 60. The first pixel layer 20 is a type I pixel layer, and the second pixel layer 30 is a type II pixel layer. The color conversion layer 320 is disposed above the corresponding sub-pixel 50 in the first pixel layer to convert the emitted color of the sub-pixel 50.

[0328] Or, see Figure 33 The microdisplay device has two pixel layers, namely a first pixel layer 20 and a second pixel layer 30. Both the first pixel layer 20 and the second pixel layer 30 are type-1 pixel layers. The top conductive layers of the sub-pixels of the first and second layers are independent and interconnected with each other through the interconnecting conductive part 901 of the common conductive member. The color conversion layer 320 is disposed above the corresponding sub-pixel 50 in the first pixel layer to convert the emitted color of the sub-pixel 50.

[0329] 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.

[0330] The microdisplay devices of the above embodiments simplify the electrical connection structure, are easier to fabricate, effectively increase the effective light-emitting area of ​​the lower sub-pixels, and are more conducive to the best light distribution effect, thereby effectively improving the light efficiency and reliability of the display device.

[0331] 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.

[0332] 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 first type of electrode contact is provided on the drive backplate; Multiple pixel layers, all of which 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 of the sub-pixels located in different pixel layers in the mother pixel is electrically connected to the corresponding top conductive layer, and the bottom of each of the sub-pixels is electrically connected to the corresponding first type of electrode contact. At least one pixel layer is a type I pixel layer, and the bottom of each of the sub-pixels in the type I pixel layer is electrically connected to the corresponding first type electrode contact through an independent conductive block, and the conductive block corresponds one-to-one with the first type electrode contact; In 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 and is part of the sub-pixel itself. An interconnecting conductive element passes through the channel. The top end of the interconnecting conductive element inside the channel is electrically connected to the bottom end of the other sub-pixel in the upper pixel layer. The bottom end of the interconnecting conductive element inside the channel is electrically connected to a corresponding first type of electrode contact. The projection area of ​​the upper sub-pixel connected to the interconnecting conductive element inside the channel on the driving backplate is a first projection area. The projection area of ​​the peripheral light-emitting area around 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 peripheral light-emitting area is at least partially emitted through the periphery of the upper sub-pixel electrically connected to the interconnecting conductive element inside the channel.

2. The microdisplay device according to claim 1, characterized in that: The conductive block has an electrical contact area for electrical connection to the bottom of the corresponding sub-pixel in the type I pixel layer, and the area of ​​the electrical contact area is smaller than the area of ​​the bottom surface of the corresponding sub-pixel in the type I pixel layer to which it is electrically connected.

3. The microdisplay device according to claim 1, characterized in that: The top conductive layers at the top of the sub-pixels located in different pixel layers in the mother pixel are interconnected to form a top common electrode structure.

4. The microdisplay device according to claim 3, characterized in that: Each of the sub-pixels located in different pixel layers of the mother pixel has its own top conductive layer, and they do not share the same top conductive layer. Furthermore, the top conductive layers in the same pixel layer are all located above the electrically connected sub-pixels.

5. The microdisplay device according to claim 3, characterized in that: At least two of the child pixels in the mother pixel share a top conductive layer, and the child pixels that share a top conductive layer are located in different pixel layers.

6. The microdisplay device according to any one of claims 4 or 5, characterized in that: It also includes a metal reinforcement, at least one of the top conductive layers being electrically connected to the metal reinforcement.

7. The microdisplay device according to claim 6, characterized in that: The metal reinforcement is located above the electrically connected top conductive layer.

8. The microdisplay device according to claim 6, characterized in that: The metal reinforcement is located below the electrically connected top conductive layer.

9. The microdisplay device according to claim 8, characterized in that: The metal reinforcement surrounds the periphery of one of the sub-pixels, which is electrically connected to the top conductive layer.

10. The microdisplay device according to claim 3, characterized in that: It also includes a second type of electrode contact with the opposite polarity to the first type of electrode contact, and the top conductive layers of multiple sub-pixels in the mother pixel are all connected to the second type of electrode contact through a common conductive element.

11. The microdisplay device according to claim 10, characterized in that: The bottom end of the common electrode is in direct contact with the corresponding second type of electrode contact.

12. The microdisplay device according to claim 10, characterized in that: At least two of the child pixels in the mother pixel share a top conductive layer, and the common electrode conductive element is in direct contact with the shared top conductive layer to achieve electrical connection; or, the common electrode conductive element is electrically connected to the shared top conductive layer through a transition conductive element.

13. The microdisplay device according to claim 10, characterized in that: The top of each of the sub-pixels in at least two different pixel layers of the mother pixel is provided with a separate top conductive layer without sharing it. The common conductive element includes an interconnecting conductive portion. Two adjacent top conductive layers are interconnected through the interconnecting conductive portion to achieve electrical connection. At least one top conductive layer is in direct contact with the electrically connected interconnecting conductive portion to achieve electrical connection; or, at least one top conductive layer is electrically connected to the electrically connected interconnecting conductive portion through a metal reinforcement.

14. The microdisplay device according to any one of claims 4 or 5, characterized in that: The top of the sub-pixel is in contact with the electrically connected top conductive layer, or the top of the sub-pixel and at least part of its sidewalls are in contact with the electrically connected top conductive layer.

15. The microdisplay device according to claim 3, characterized in that: The bottom of each sub-pixel in the type-1 pixel layer is electrically connected to its corresponding conductive block via a metal reflective layer.

16. The microdisplay device according to claim 15, characterized in that: The sub-pixels in the type-1 pixel layer are electrically connected to the metal reflective layer only at their bottom ends, or the bottom ends and at least part of the sidewalls of the sub-pixels in the type-1 pixel layer are electrically connected to the metal reflective layer.

17. The microdisplay device according to claim 15, characterized in that: The upper part of the metal reflective layer has a peripheral reflective portion, and the peripheral reflective portion surrounds the sub-pixel in the type-1 pixel layer. The peripheral reflective portion and the outer wall of the surrounding sub-pixel are insulated and isolated by a first insulating layer.

18. The microdisplay device according to claim 17, characterized in that: An aperture is formed inside one of the sub-pixels in one of the pixel layers of the first type. An outer light-emitting area is formed around the aperture. An inner reflective part is also formed on the upper part of the metal reflective layer. The inner reflective part is located inside the aperture and surrounds the outer periphery of the interconnecting conductive part inside the aperture. The inner reflective part and the inner sidewall of the outer light-emitting area are insulated and isolated by the first insulating layer.

19. The microdisplay device according to claim 15, characterized in that: The bottom end of the sub-pixel in the type I pixel layer is in direct contact with the metal reflective layer to achieve electrical connection; or the bottom end of the sub-pixel in the type I pixel layer is electrically connected to the metal reflective layer through an ohmic contact layer.

20. The microdisplay device according to claim 1, characterized in that: The top end of the interconnecting conductive element inside the channel is electrically connected to the bottom end of a sub-pixel in the upper layer of the first type of pixel layer via a conductive block, and the bottom end of the interconnecting conductive element inside the channel is electrically connected to the corresponding first type of electrode contact.

21. The microdisplay device according to claim 1, characterized in that: All of the pixel layers are type I pixel layers.

22. The microdisplay device according to claim 1, characterized in that: At least one pixel layer is a type II pixel layer, and the bottom end of the sub-pixel in the type II pixel layer is electrically connected to the corresponding first type electrode contact through a bottom conductive layer. The bottom surface of the sub-pixel in the type II pixel layer is completely covered by the bottom conductive layer.

23. The microdisplay device according to claim 22, characterized in that: The bottom conductive layer is a metal bonding layer, and a first peripheral metal fence is formed on the upper part of the metal bonding layer. The sub-pixel in the type-two pixel layer is surrounded by the first peripheral metal fence, and the first peripheral metal fence and the outer wall of the surrounding sub-pixel are insulated from each other.

24. The microdisplay device according to claim 23, characterized in that: An aperture is formed inside one of the sub-pixels in one of the type-two pixel layers. An outer light-emitting area is formed around the aperture. A first inner metal fence is formed inside the aperture. The first inner metal fence surrounds the outer perimeter of the interconnecting conductive element inside the aperture. The first inner metal fence and the inner sidewall of the outer light-emitting area are insulated from each other.

25. The microdisplay device according to claim 1, characterized in that: The sub-pixel with the aperture and any of the above sub-pixels connected to the internal interconnecting conductive element of the aperture are arranged coaxially; or, the sub-pixel with the aperture and at least one of the above sub-pixels connected to the internal interconnecting conductive element of the aperture are arranged off-axis.

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

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

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

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

30. The microdisplay device according to claim 1, characterized in that: It also includes a color conversion layer, which is located on the light-emitting path of the corresponding sub-pixel in one of the pixel layers.

31. The microdisplay device according to claim 30, characterized in that: It has two pixel layers, at least one of which is the type I pixel layer, and the color conversion layer is located above the corresponding sub-pixel in the lower pixel layer of the two pixel layers.

32. A method for fabricating a microdisplay device, characterized in that: include, A drive backplane is provided, wherein a first 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. Each pixel layer has 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 of the sub-pixels located in different pixel layers within the mother pixel is electrically connected to the corresponding top conductive layer, and the bottom of each of the sub-pixels is electrically connected to the corresponding first type of electrode contact. At least one pixel layer is a type I pixel layer, and the bottom of each of the sub-pixels in the type I pixel layer is electrically connected to the corresponding first type electrode contact through an independent conductive block, and the conductive block corresponds one-to-one with the first type electrode contact; In this configuration, among two sub-pixels located in different pixel layers, one of the sub-pixels in the lower pixel layer has an internal aperture. The periphery of the aperture forms a peripheral light-emitting area, which is part of the sub-pixel itself. An interconnecting conductive element passes through the aperture. The top end of the interconnecting conductive element inside the aperture is electrically connected to the bottom end of the other sub-pixel in the upper pixel layer, and the bottom end of the interconnecting conductive element inside the aperture is electrically connected to a corresponding first-type electrode contact. The projection area of ​​the upper sub-pixel connected to the interconnecting conductive element inside the aperture on the driving backplate is a first projection area, and the projection area of ​​the peripheral light-emitting area outside the aperture 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 peripheral light-emitting area is at least partially emitted through the periphery of the upper sub-pixel electrically connected to the interconnecting conductive element inside the aperture.

33. The method for fabricating a microdisplay device according to claim 32, characterized in that: When stacking the type-one pixel layer, the fabrication method includes, A compound semiconductor layer is selected as a type I pixel layer. The compound semiconductor layer is etched to obtain sub-pixels, and independent conductive blocks are prepared so that the end of the sub-pixel in the type I pixel layer that is close to the driving backplane is electrically connected to the corresponding conductive block. Then the prepared type I pixel layer is directly bonded to the driving backplane, or the prepared type I pixel layer is bonded to the pixel layer adjacent below it; After bonding, the bottom ends of each sub-pixel in the first-type pixel layer are each electrically connected to the corresponding first-type electrode contact through an independent conductive block, and the conductive block corresponds one-to-one with the first-type electrode contact.

34. The method for fabricating a microdisplay device according to claim 33, characterized in that: When fabricating the conductive block in the type-1 pixel layer, the fabrication method includes covering the end of the sub-pixel near the driving backplate in the type-1 pixel layer with an insulating medium, and forming a filling hole in the insulating medium and filling the filling hole with a conductive material to obtain the conductive block, such that the end of the sub-pixel near the driving backplate in the type-1 pixel layer is electrically connected to the corresponding conductive block.

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