Multi-color LED pixel unit and micro-LED display panel

Abstract

A multicolor light-emitting pixel unit includes a substrate, a bottom conductive layer formed on the substrate, a top conductive layer formed above the bottom conductive layer, and a light-emitting layer formed between the top conductive layer and the bottom conductive layer. The light-emitting layer includes a plurality of micro-gap structures.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority benefit of U.S. Patent Application No. 16 / 567,103, filed on September 11, 2019. The content of the foregoing application is incorporated herein by reference in its entirety. Technical field

[0003] This disclosure generally relates to the field of micro - light - emitting diode technology, and more particularly to multi - color LED pixel units and micro - LED display panels. Background art

[0004] A light - emitting diode (LED) is a semiconductor diode that can convert electrical energy into light energy. Conventional light - emitting diodes include a P - N junction with unidirectional conduction. Under a forward bias, holes flow from the P - region into the N - region, and electrons flow from the N - region into the P - region, and the combination of electrons in the N - region and holes in the P - region generates spontaneous emission of light - emitting excitation. Electrons and holes have different energy states in different semiconductor materials, so the energy generated by the combination of electrons and holes is different. The higher the energy, the shorter the wavelength of the excitation light. Therefore, LEDs can emit different lights of different wavelengths from ultraviolet light to infrared light, thereby producing multi - color LEDs.

[0005] Multi - color LEDs that emit white light or other colors of light have a wide range of applications, most of which are used in the display field. Conventional LED display panels are formed by assembling monochromatic LEDs one by one on a substrate. The methods for assembling monochromatic LEDs include: bonding the LEDs to an interconnect layer through the metal wires or connection electrodes of the LEDs using a metal bonding process or other processes. The process of assembling other - colored LEDs is not carried out until the process of assembling monochromatic LEDs is completed, resulting in a complex process, increased processing difficulty, and increased production costs. In addition, multi - color display panels manufactured by assembling or forming individual LEDs one by one have higher power consumption and reduced brightness and color. Summary of the invention

[0006] According to one aspect of the present disclosure, a multi - color light - emitting pixel unit is provided. The multi - color light - emitting pixel unit includes a substrate, a bottom conductive layer formed on the substrate, a top conductive layer formed above the bottom conductive layer, and a light - emitting layer formed between the top conductive layer and the bottom conductive layer. The light - emitting layer includes a plurality of micro - gap structures.

[0007] According to another aspect of the present disclosure, a micro - display panel is provided. The micro - display panel includes the multi - color light - emitting pixel unit described above. Brief description of the drawings

[0008] FIG. 1 is a cross-sectional view showing a multi-color light-emitting pixel unit according to an embodiment of the present disclosure.

[0009] FIG. 2 is a cross-sectional view showing a multi-color light-emitting pixel unit according to an embodiment of the present disclosure.

[0010] FIG. 3 is a cross-sectional view showing a multi-color light-emitting pixel unit according to an embodiment of the present disclosure.

[0011] FIG. 4 is a top view of a multi-color light-emitting pixel unit according to an embodiment of the present disclosure.

[0012] FIG. 5 is a cross-sectional view showing a multi-color light-emitting pixel unit according to an embodiment of the present disclosure.

[0013] FIG. 6 is a flowchart showing a method of manufacturing the multi-color light-emitting pixel unit shown in FIG. 1 according to an embodiment of the present disclosure.

[0014] FIGS. 7 to 10 are cross-sectional views showing structures formed in steps of the method in FIG. 6 according to an embodiment of the present disclosure.

[0015] FIG. 11 is a flowchart showing details of step S601 in FIG. 6 according to an embodiment of the present disclosure.

[0016] FIGS. 12 to 21 are cross-sectional views showing structures formed in steps of FIG. 11 according to an embodiment of the present disclosure.

[0017] FIG. 22 is a flowchart showing details of step S604 in FIG. 6 according to an embodiment of the present disclosure.

[0018] FIGS. 23 to 25 are cross-sectional views showing structures formed in steps of FIG. 22 according to an embodiment of the present disclosure.

[0019] FIGS. 26 and 27 are cross-sectional views showing structures formed during the process of manufacturing a first electrical connector according to an embodiment of the present disclosure.

[0020] FIG. 28 is a cross-sectional view showing a multi-color light-emitting pixel unit having a micro-gap structure according to an embodiment of the present disclosure.

[0021] FIG. 29 is a flowchart showing a method of manufacturing the multi-color light-emitting pixel unit shown in FIG. 3 according to an embodiment of the present disclosure.

[0022] FIGS. 30 to 34 are cross-sectional views showing structures formed in steps of the method in FIG. 29 according to an embodiment of the present disclosure.

[0023] FIG. 35 is a flowchart showing details of step S701 in FIG. 29 according to an embodiment of the present disclosure.

[0024] FIG. 36 is a cross-sectional view of a micro-gap structure formed in three types of light-emitting layers according to an embodiment of the present disclosure.

[0025] FIG. 37 is a flowchart showing details of step S705 in FIG. 29 according to an embodiment of the present disclosure.

[0026] FIGS. 38 to 40 are cross-sectional views showing structures formed in steps in FIG. 37 according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] Reference will now be made in detail to the proposed preferred embodiments to provide a further understanding of the present invention. The specific embodiments and drawings discussed are merely illustrative of specific ways of practicing and using the present invention and do not limit the scope of the present invention or the appended claims.

[0028] Hereinafter, with reference to FIGS. 1 to 40, the present disclosure will be further described by embodiments of the present disclosure. It should be noted that all the drawings are in a very simplified form and the inaccurate scale is only used to help explain the embodiments of the present disclosure conveniently and clearly.

[0029] The multi-color light-emitting pixel unit disclosed herein includes at least one type of light-emitting transistor, or several types of light-emitting transistors. Each type of light-emitting transistor includes an upper conductive layer, a bottom conductive layer, and a light-emitting layer between the upper conductive layer and the bottom conductive layer. All the light-emitting transistors share the same upper conductive layer and the same bottom conductive layer. It should be noted that the light-emitting layer can be a single layer or multiple layers. An intermediate layer can be disposed between two light-emitting layers among multiple light-emitting layers in the same light-emitting diode. Assume that the multi-color light-emitting pixel unit includes first to M-th type of light-emitting transistors, where M is an integer and not less than two. Each of the first to M-th type of light-emitting transistors includes at least the same type of light-emitting layer. For example, each of the first to M-th type of light-emitting transistors includes a first type of light-emitting layer. Any one of the second to M-th type of light-emitting layers is different from the first type of light-emitting layer. The present disclosure also provides a micro display panel including a plurality of the above pixel units arranged in a matrix.

[0030] In some embodiments, the light-emitting transistor may be at least one of a light-emitting diode (LED), a Schottky light-emitting transistor, etc. The top conductive layer of the light-emitting transistor is but not limited to a transparent conductive layer, and the bottom conductive layer of the light-emitting transistor is but not limited to a metal layer. Hereinafter, the LED is used as an example of the light-emitting transistor, but this does not limit the scope of the present disclosure. Those skilled in the art can change the LED into another light-emitting transistor according to conventional technical means.

[0031] FIG. 1 is a cross-sectional view showing a multicolor light-emitting pixel unit 1000 according to an embodiment of the present disclosure. Referring to FIG. 1, the multicolor light-emitting pixel unit 1000 includes at least a first type of LED 01 and a second type of LED 02 arranged side by side on a substrate 100. The top of the first type of LED 01 and the top of the second type of LED 02 are not in the same horizontal plane. The type of the first type of LED 01 is different from the type of the second type of LED 02. Here, as shown in FIG. 1, the top of the first type of LED 01 is lower than the top of the second type of LED 02. According to the embodiment, the first type of LED 01 is selected from one of a red LED, a green LED, a blue LED, a yellow LED, an orange LED, or a cyan LED, and the second type of LED 02 is selected from one of a green LED, a blue LED, a red LED, a yellow LED, an orange LED, or a cyan LED. In addition, the size of the light-emitting area of the first type of LED 01 is different from the size of the light-emitting area of the second type of LED 02. For example, the first type of LED 01 is a red LED, the second type of LED 02 is a green LED, and the size of the light-emitting area of the red LED is different from the size of the light-emitting area of the green LED. In addition, according to different colors that may be required, the light-emitting area of the green LED may be smaller than the light-emitting area of the red LED.

[0032] In addition, an isolation structure 07 is disposed between the first type of LED and the second type of LED. In the embodiment shown in FIG. 1, the isolation structure 07 between the first type of LED 01 and the second type of LED 02 is an isolation trench. The multi-color light-emitting pixel unit 1000 includes a first metal layer, a first type of light-emitting layer, a second metal layer, and a second type of light-emitting layer. As shown in FIG. 1, the first type of LED 01 includes at least a first section 101-1 of the first metal layer and a first section 102-1 of the first type of light-emitting layer in order from bottom to top. The first section 101-1 of the first metal layer constitutes the bottom conductive layer of the first type of LED 01. The second type of LED 02 includes at least a second section 101-2 of the first metal layer, a second section 102-2 of the first type of light-emitting layer, a first section 201-1 of the second metal layer, a first section 202-2 of the second type of light-emitting layer, and a first electrical connector 203 in order from bottom to top. The first section 101-1 of the first metal layer and the second section 101-2 of the first metal layer are electrically connected to the substrate 100. The isolation structure 07 isolates the first section 101-1 of the first metal layer in the first type of LED 01 from the second section 101-2 of the first metal layer in the second type of LED 02. The isolation structure 07 also isolates the first section 102-1 of the first type of light-emitting layer in the first type of LED 01 from the second section 102-2 of the first type of light-emitting layer in the second type of LED 02. In addition, to simplify the manufacturing process, the first section 201-1 of the second metal layer, the second section 102-2 of the first type of light-emitting layer, and the second section 101-2 of the first metal layer in the second type of LED 02 are electrically connected to each other through the first electrical connector 203. According to one embodiment, the first electrical connector 203 can be attached to and contact a part or all of the sidewall surface of the second type of LED 02. Alternatively, the first electrical connector 203 can be attached to and contact only the surfaces of the first section 201-1 of the second metal layer and the second section 101-2 of the first metal layer in the second type of LED 02. Or alternatively, the first electrical connector 203 can be formed as a conductive side arm that is attached to and contacts the sidewalls of the first section 201-1 of the second metal layer, the second section 102-2 of the first type of light-emitting layer, and the second section 101-2 of the first metal layer. The electrical connector 203 between the second section 101-2 of the first metal layer and the first section 201-1 of the second metal layer in the second type of LED 02 can have other shapes, such as a curve. In the embodiment shown in FIG. 1, the first electrical connector 203 is attached to the sidewall of the second type of LED 02 such that the first electrical connector 203 follows the surface topography of the sidewall of the second type of LED 02.

[0033] Referring to FIG. 1, a top isolation layer 04 and a top transparent conductive layer 05 are disposed on a first section 102-1 of a first-type light-emitting layer in a first-type LED 01 and a first section 202-1 of a second-type light-emitting layer in a second-type LED 02. The top isolation layer 04 covers the first section 102-1 of the first-type light-emitting layer, the first section 202-1 of the second-type light-emitting layer, and the exposed substrate 100. The top isolation layer 04 has openings that expose portions of the top surfaces of the first section 102-1 of the first-type light-emitting layer and the first section 202-1 of the second-type light-emitting layer. The top transparent conductive layer 05 covers the top isolation layer 04 and is formed in the openings of the top isolation layer 04, and thus contacts the exposed top surfaces of the first section 102-1 of the first-type light-emitting layer and the first section 202-1 of the second-type light-emitting layer via the openings.

[0034] The substrate 100 is an integrated circuit (IC) substrate. The IC substrate includes an interconnect layer that is electrically connected to a first section 101-1 of a first metal layer in the first-type LED 01 and a second section 101-2 of a first metal layer in the second-type LED 02. Since the first electrical connector 203 is connected to the second section 101-2 of the first metal layer in the second-type LED 02, the first electrical connector 203 is connected to the interconnect layer in the substrate 100. In addition, referring to FIG. 1, the bottom of the first electrical connector 203 extends to the substrate 100 to connect to the interconnect layer. Here, the IC substrate includes at least a driving circuit. The driving circuit controls each LED separately.

[0035] Figure 2 is a cross-sectional view showing a multi-color light-emitting pixel unit 2000 according to an embodiment of the present disclosure. Referring to FIG. 2, the multi-color light-emitting pixel unit 2000 includes at least a first type of LED 01, a second type of LED 02, and a third type of LED 03 disposed on the same substrate 100. The third type of LED 03 is different from the first type of LED 01 and the second type of LED 02. Here, the first type of LED 01 is selected from one of a red LED, a green LED, a blue LED, a yellow LED, an orange LED, or a cyan LED; the second type of LED 02 is selected from one of a green LED, a blue LED, a red LED, a yellow LED, an orange LED, or a cyan LED; and the third type of LED 03 is selected from one of a blue LED, a red LED, a green LED, a yellow LED, an orange LED, or a cyan LED. For example, a red LED is selected as the first type of LED 01, a green LED is selected as the second type of LED 02, and a blue LED is selected as the third type of LED 03. Referring to FIG. 2, the height of the third type of LED 03 is different from the height of the first type of LED 01. In addition, the height of the first type of LED 01 is different from the height of the second type of LED 02, while the height of the second type of LED 02 is the same as the height of the third type of LED 03. In other embodiments, the height of the third type of LED 03, the height of the first type of LED 01, and the height of the second type of LED 02 may be different from each other, as shown in FIG. 3.

[0036] In the multi-color light-emitting pixel unit 2000, the structures of the first type of LED 01 and the second type of LED 02 are the same as those of the first type of LED 01 and the second type of LED 02 in the multi-color light-emitting pixel unit 2000, so their detailed descriptions will not be repeated. The third type of LED 03 in the multi-color light-emitting pixel unit 2000 includes at least a third section 101-3 of the first metal layer, a third section 102-3 of the first type of light-emitting layer, a first section 301-1 of the third metal layer, and a first section 302-1 of the third type of light-emitting layer in order from bottom to top, as well as a second electrical connector 303 connecting the third section 101-3 of the first metal layer and the first section 301-1 of the third metal layer. The multi-color light-emitting pixel unit 2000 further includes a top isolation layer 04 that covers the first type of LED 01, the second type of LED 02, and the third type of LED 03 and has an opening that exposes a part of the first section of the first type of light-emitting layer 102-1 in the first type of LED 01, a part of the first section of the second type of light-emitting layer 202-1, and a part of the first section of the third type of light-emitting layer 302-1. A top electrode layer is formed on top of the top isolation layer 04 and is in contact with the first section 102-1 of the first type of light-emitting layer, the first section 202-1 of the second type of light-emitting layer, and the first section 302-1 of the third type of light-emitting layer through the opening of the top isolation layer 04.

[0037] Figure 3 is a cross-sectional view showing a multi-color light-emitting pixel unit 3000 according to an embodiment of the present disclosure. Referring to Figure 3, in the multi-color light-emitting pixel unit 3000, the top of the third type of LED 03 is higher than the top of the second type of LED 02, while the height of the first type of LED is different from the height of the second type of LED 03.

[0038] FIG. 4 is a top view of a multi-color light-emitting pixel unit 4000 according to an embodiment of the present disclosure. The multi-color light-emitting pixel unit 4000 may be the multi-color light-emitting pixel unit 2000 shown in FIG. 2 or the multi-color light-emitting pixel unit 3000 shown in FIG. 3. FIG. 4 shows the arrangement of three types of LEDs 01, 02, and 03 in the pixel unit, but the present disclosure also includes other arrangements, such as a matrix. Here, the size of the light-emitting area of the third type of LED 03 is different from the size of the light-emitting area of the first type of LED 01 and is different from the size of the light-emitting area of the second type of LED 02. For example, the first type of LED 01 is a red LED, the second type of LED 02 is a green LED, and the third type of LED 03 is a blue LED. The size of the light-emitting area of each of the first type of LED 01, the second type of LED 02, and the third type of LED 03 may be determined according to the color of light that the multi-color light-emitting pixel unit 4000 needs to emit. When white light is needed, the size of the light-emitting area of the red LED is larger than the size of the light-emitting area of the green LED, and the size of the light-emitting area of the blue LED is larger than the size of the light-emitting area of the green LED. As shown in FIG. 4, the space between the red LED and the blue LED is larger than the space between the blue LED and the green LED; the space between the red LED and the green LED is larger than the space between the blue LED and the green LED, thereby achieving a better light-emitting effect.

[0039] Referring back to FIG. 3, the isolation structure 07 is disposed between two of the first type of LED 01, the second type of LED 02, and the third type of LED 03. The isolation structure is an isolation trench. The first type of LED 01, the second type of LED 02, and the third type of LED 03 are formed by a first metal layer 101, a first type of light-emitting layer 102, a second metal layer 201, a second type of light-emitting layer 202, a third metal layer 301, and a third type of light-emitting layer 302. The first type of LED 01 and the second type of LED 02 in FIG. 3 are the same as the first type of LED 01 and the second type of LED 02 in FIG. 2. Specifically, as shown in FIG. 3, the first type of LED 01 includes at least a first section 101-1 of the first metal layer and a first section 102-1 of the first type of light-emitting layer in order from bottom to top. The second type of LED 02 includes at least a second section 101-2 of the first metal layer, a second section 102-2 of the first type of light-emitting layer, a first section 201-1 of the second metal layer, a first section 202-1 of the second type of light-emitting layer, and a first electrical connector 203 in order from bottom to top. The third type of LED 03 includes at least a third section 101-3 of the first metal layer, a third section 102-3 of the first type of light-emitting layer, a second section 201-2 of the second metal layer, a second section 202-2 of the second type of light-emitting layer, a first section 301-1 of the third metal layer, a first section 302-1 of the third type of light-emitting layer, and a second electrical connector 303 in order from bottom to top. As shown in FIG. 3, the first section 101-1 of the first metal layer, the second section 101-2 of the first metal layer, and the third section 101-3 of the first metal layer are electrically connected to the substrate 100. The first electrical connector 203 in the second type of LED 02 electrically connects the first section 201-1 of the second metal layer to the second section 101-2 of the first metal layer. The second electrical connector 303 in the third type of LED 03 electrically connects the first section 301-1 of the third metal layer to the second section 201-2 of the second metal layer and the third section 101-3 of the first metal layer.The isolation structure 07 isolates the first section 101-1 of the first metal layer in the first type of LED 01 from the second section 101-2 of the first metal layer in the second type of LED 02 and the third section 101-3 of the first metal layer in the third type of LED 03, isolates the first section 102-1 of the first type of light-emitting layer in the first type of LED 01 from the second section 102-2 of the first type of light-emitting layer in the second type of LED 02 and the third section 102-3 of the first type of light-emitting layer in the third type of LED 03, isolates the first section 201-1 of the second metal layer in the second type of LED 02 from the second section 201-2 of the second metal layer in the third type of LED 03, and isolates the first section 202-1 of the second type of light-emitting layer in the second type of LED 02 from the second section 202-2 of the second type of light-emitting layer in the third type of LED 03. It should be noted that the first electrical connector 203 is used to connect the second section 102-2 of the first type of light-emitting layer in the second type of LED 02 to the second section 101-2 of the first metal layer, and the second electrical connector 303 is used to connect the second section 202-2 of the second type of light-emitting layer and the third section 102-3 of the first type of light-emitting layer in the third type of LED 03 to the third section 101-3 of the first metal layer. Therefore, to simplify the manufacturing process, in the same manner as in FIG. 1, the first electrical connector 203 also connects the second section 102-2 of the first type of light-emitting layer to the second section 101-2 of the first metal layer. That is, in the second type of LED 02, the first electrical connector 203 connects the first section 201-1 of the second metal layer and the second section 102-2 of the first type of light-emitting layer to the second section 101-2 of the first metal layer. The second electrical connector 303 also connects the second section 202-2 of the second type of light-emitting layer to the third section 101-3 of the first metal layer. That is, in the third type of LED 03, the second electrical connector 303 connects the first section 301-1 of the third metal layer, the second section 202-2 of the second type of light-emitting layer, and the second section 201-2 of the second metal layer to the third section 101-3 of the first metal layer. Alternatively, the second electrical connector 303 also connects the second section 202-2 of the second type of light-emitting layer and the third section 102-3 of the first type of light-emitting layer to the third section 101-3 of the first metal layer. That is, in the third type of LED 03, the second electrical connector 303 connects the first section 301-1 of the third metal layer, the second section 202-2 of the second type of light-emitting layer, the second section 201-2 of the second metal layer, and the third section 102-3 of the first type of light-emitting layer to the third section 101-3 of the first metal layer.In addition, the bottoms of the first electrical connector 203 and the second electrical connector 303 respectively and directly contact the substrate 100, thereby simplifying the manufacturing process. It should be noted that the materials of the first electrical connector 203 and the second electrical connector 303 are formed of conductive metal. In an embodiment, the second electrical connector 303 is attached to and contacts the sidewall surface of the third type of LED 03.

[0040] In one embodiment, the first type of light-emitting layer is a red light-emitting layer, the second type of light-emitting layer is a green light-emitting layer, and the third type of light-emitting layer is a blue light-emitting layer. The first type of LED 01 is a red LED 01, the second type of LED 02 is a green LED 02, and the third type of LED 03 is a blue LED 03. In the red LED 01, the voltage applied between the top transparent conductive layer 05 and the first section 101-1 of the first metal layer is applied to the first section 102-1 of the red light-emitting layer. Therefore, the first section 102-1 of the red light-emitting layer in the red LED 01 emits red light. In the green LED 02, the first electrical connector 203 electrically connects the second section 102-2 of the red light-emitting layer to the second section 101-2 of the first metal layer, such that the voltage applied between the top transparent conductive layer 05 and the second section 101-2 of the first metal layer is only applied to the first section 202-1 of the green light-emitting layer. Therefore, only the first section 202-1 of the green light-emitting layer in the green LED 02 emits green light, while the second section 102-2 of the red light-emitting layer in the green LED 02 does not emit light. In the third type of LED 03, the second electrical connector 303 electrically connects the third section 102-3 of the red light-emitting layer and the second section 202-2 of the green light-emitting layer to the third section 101-3 of the first metal layer, such that the voltage applied between the top transparent conductive layer 05 and the third section 101-3 of the first metal layer is only applied to the first section 302-1 of the blue light-emitting layer. Therefore, only the first section 302-1 of the blue light-emitting layer in the blue LED 03 emits blue light, while the third section 102-3 of the red light-emitting layer and the second section 202-2 of the green light-emitting layer in the blue LED 03 do not emit light.

[0041] Referring again to FIG. 3, a top isolation layer 04 and a top transparent conductive layer 05 are disposed on the first type of LED 01, the second type of LED 02, and the third type of LED 03. The top isolation layer 04 covers the first section 102-1 of the first type of light-emitting layer, the first section 202-1 of the second type of light-emitting layer, the first section 302-1 of the third type of light-emitting layer, and the exposed substrate 100. Openings are disposed in the top isolation layer 04 to expose portions of the top surfaces of the first section 102-1 of the first type of light-emitting layer, the first section 202-1 of the second type of light-emitting layer, and the first section 302-1 of the third type of light-emitting layer. The top transparent conductive layer 05 covers the top isolation layer 04 and is formed in the openings of the top isolation layer 04, thereby contacting the exposed top surfaces of the first section 102-1 of the first type of light-emitting layer, the exposed top surfaces of the first section 202-1 of the second type of light-emitting layer, and the exposed top surfaces of the first section 302-1 of the third type of light-emitting layer.

[0042] The detailed description of the substrate 100 in the multi-color light-emitting pixel unit 3000 having at least three types of LEDs corresponds to the description of FIG. 1 and will not be repeated here. It should be noted that the interconnecting layer in the IC substrate 100 is electrically connected to the first type of LED 01, the second type of LED 02, and the third type of LED 03. The drive circuits in the IC substrate 100 control each LED respectively.

[0043] Among the multi-color light-emitting pixel units 1000 to 4000 in FIGS. 1 to 4, one or more of the light-emitting layers 102, 202, and 302 may have a micro-gap structure. For example, in the multi-color light-emitting pixel unit 1000 shown in FIG. 1, the first type of light-emitting layer 102 may have a micro-gap structure, or the second type of light-emitting layer 202 may have a micro-gap structure, or both the first type of light-emitting layer 102 and the second type of light-emitting layer 202 may have a micro-gap structure. As another example, in the multi-color light-emitting pixel unit 3000 shown in FIG. 3, the first type of light-emitting layer 102 may have a micro-gap structure, or the second type of light-emitting layer 202 may have a micro-gap structure, or the third type of light-emitting layer 302 may have a micro-gap structure, or both the first type of light-emitting layer 102 and the second type of light-emitting layer 202 may have a micro-gap structure, or both the second type of light-emitting layer 202 and the third type of light-emitting layer 302 may have a micro-gap structure, or both the first type of light-emitting layer 102 and the third type of light-emitting layer 302 may have a micro-gap structure, or all of the first type of light-emitting layer 102, the second type of light-emitting layer 202, and the third type of light-emitting layer 302 may have a micro-gap structure. Herein, each of the micro-gap structures in the multi-color light-emitting pixel units 1000 to 3000 shown in FIGS. 1 to 3 may be, but is not limited to, an air gap. The air gap is sealed. Preferably, the cross-sectional size of the air gap is not greater than 2 nm, thereby releasing the stress in the light-emitting layer and avoiding bending of the light-emitting layer without affecting the light-emitting efficiency of the light-emitting layer. Herein, the cross-sectional size of the air gap may be the diameter of the cross-section of the air gap, or the length or width of the cross-section of the air gap.

[0044] FIG. 5 is a cross-sectional view showing a multi-color light-emitting pixel unit 5000 according to an embodiment of the present disclosure. As shown in FIG. 5, each of the first type of light-emitting layer 102, the second type of light-emitting layer 202, and the third type of light-emitting layer 302 may have a plurality of micro-gap structures 06. Each of the micro-gap structures 06 extends in a direction perpendicular to the substrate 100 and passes through the corresponding light-emitting layer, such as the first type of light-emitting layer 102, the second type of light-emitting layer 202, or the third type of light-emitting layer 302. When multiple light-emitting layers are used in the embodiment, the micro-gap structures 06 are arranged in at least one light-emitting layer, preferably in the top light-emitting layer.

[0045] Still referring to FIG. 5, the micro-gap structures 06 are staggered among multiple light-emitting layers. That is, the micro-gap structures 06 in the first type of light-emitting layer 102 are not vertically aligned with the micro-gap structures 06 in the second type of light-emitting layer 202, and the micro-gap structures 06 in the second type of light-emitting layer 202 are not vertically aligned with the micro-gap structures 06 in the third type of light-emitting layer 302. In each of the second type of LED 02 and the third type of LED 03, the micro-gap structures in the first type of light-emitting layer 102 are isolated and sealed between the second metal layer 201 on the top of the first type of light-emitting layer 102 and the first metal layer 101 at its bottom. In the third type of LED 03, the micro-gap structures 06 in the second type of light-emitting layer 202 are isolated and sealed between the third metal layer 301 on the top of the second type of light-emitting layer 202 and the second metal layer 201 at its bottom, and the micro-gap structures 06 in the third type of light-emitting layer 302 are isolated and sealed between the top isolation layer 04 on the top of the third type of light-emitting layer 302 and the third metal layer 301 at its bottom.

[0046] In a similar manner, in a multi-color light-emitting pixel unit including the first to the Mth type of LEDs in another embodiment of the present disclosure, the Mth type of LED has M light-emitting layers, and metal layers are arranged at the bottoms of each light-emitting layer, where M is a positive integer and greater than or equal to two. In each of the first to the Mth type of LEDs, a top conductive layer (as an upper conductive layer) is arranged on the top of the top light-emitting layer such that the micro-gap structures in the top light-emitting layer can be isolated and sealed between the top conductive layer and the metal layer at the bottom of the top light-emitting layer. The micro-gap structures in each light-emitting layer are isolated and sealed between the metal layers respectively at the top and bottom of the opposite light-emitting layer.

[0047] In addition, similar to the multi-color light-emitting pixel units 1000 to 4000 in FIGS. 1 to 4, a multi-color light-emitting pixel unit according to another embodiment of the present disclosure includes a plurality of LEDs (including the first type of LED to the Mth type of LED). The Mth type of LED includes at least all the light-emitting layers and metal layers constructed in the (M - 1)th type of LED, as well as the Mth light-emitting layer and the Mth metal layer. On this basis, the Mth type of LED has an (M - 1)th electrical connector, which is connected to the Mth metal layer, the (M - 1)th metal layer... and the first metal layer. In addition, the (M - 1)th electrical connector can be connected to the Mth metal layer, the light-emitting layer of the (M - 1)th type, the (M - 1)th metal layer... the light-emitting layer of the first type, and the first metal layer. The arrangement of the (M - 1)th electrical connector can refer to the description of the first electrical connector 203 in FIG. 1. The first to (M - 1)th electrical connectors connect the first to Mth metal layers, and the first to (M - 1)th electrical connectors can directly contact the substrate and the first metal layer. Here, there are differences from the first type of LED to the Mth type of LED. In addition, each LED can be selected from a red LED, a green LED, a blue LED, a yellow LED, an orange LED, a purple LED, or a cyan LED. Here, the LEDs of different colors are conventional LEDs, which are known to those skilled in the art and will not be described herein. In addition, the first type of LED to the Mth type of LED are spaced apart on the same substrate. The top isolation layer covers the exposed surface of the substrate and the exposed surfaces of the first to Mth type of LEDs. Each type of LED's top isolation layer has its opening, and the transparent conductive layer covers the surface of the top isolation layer and is filled in the opening, where the transparent conductive layer at the bottom of the opening is in electrical contact with the top light-emitting layer of each type of LED. Referring to FIGS. 4 and 5, in the pixel unit having M types of LEDs, the sizes of the light-emitting regions of the first to Mth type of LEDs are different from each other. According to the arrangement of the LEDs in the pixel unit, the size of the light-emitting area of the first type of LED is larger than the light-emitting areas of other types of LEDs. Optionally, the first type of LED is a red LED, and its light-emitting area is larger than the light-emitting areas of other types of LEDs. Alternatively, other types of LEDs include at least a green LED or a blue LED.

[0048] A multi-color microdisplay panel according to an embodiment of the present disclosure is also provided. The microdisplay panel includes a plurality of multi-color pixel units arranged in a matrix. The multi-color pixel units herein can be the above-mentioned LED pixel units.

[0049] The method for manufacturing a multi-color light-emitting pixel unit will be further described below with reference to the accompanying drawings.

[0050] FIG. 6 is a flowchart showing a method of manufacturing the multi-color light-emitting pixel unit shown in FIG. 1 according to an embodiment of the present disclosure. FIGS. 7 to 10 are cross-sectional views showing structures formed in the steps shown in FIG. 6 according to an embodiment of the present disclosure. Referring to FIG. 6, the method of manufacturing the multi-color light-emitting pixel unit shown in FIG. 1 includes the following steps.

[0051] In step S601, referring to FIG. 7, a stacked structure including a first metal layer 101, a first type of light-emitting layer 102, a second metal layer 201, and a second type of light-emitting layer 202 is formed on the substrate 100 from bottom to top. In other words, the first type of light-emitting layer 102 and the second type of light-emitting layer 202 are stacked on the substrate 100 from bottom to top. The first metal layer 101 is formed at the bottom of the first type of light-emitting layer 102. The second metal layer 201 is formed at the bottom of the second type of light-emitting layer 202. The second metal layer 201 is disposed between the first type of light-emitting layer 102 and the second type of light-emitting layer 202.

[0052] More specifically, the substrate 100 may be, but is not limited to, an IC substrate.

[0053] FIG. 11 is a flowchart showing details of step S601 in FIG. 6 according to an embodiment of the present disclosure. FIGS. 12 to 21 are cross-sectional views showing structures formed in the steps shown in FIG. 11 according to an embodiment of the present disclosure. Referring to FIG. 11, step S601 further includes the following specific steps.

[0054] In step S101, referring to FIG. 12, a first metal bonding layer M01 is formed on the substrate 100, a first type of light-emitting layer 102 is formed on the first substrate B1, and a second metal bonding layer M02 is formed on the top of the first type of light-emitting layer 102.

[0055] More specifically, the first metal bonding layer M01 can be prepared by, but is not limited to, physical vapor deposition (such as evaporation, sputtering, etc.). The material of the first substrate B1 is designed according to the first type of light-emitting layer 102. For example, the first substrate B1 may be a gallium nitride (GaN) substrate. The first type of light-emitting layer 102 can be formed by, but is not limited to, epitaxial growth on the first substrate B1. The second metal bonding layer M02 can be prepared by, but is not limited to, physical vapor deposition (such as evaporation).

[0056] In step S102, referring to FIG. 13 in combination with FIG. 12, the first substrate B1 is inverted up and down so that the second metal bonding layer M02 faces the first metal bonding layer M01, and then the second metal bonding layer M02 is bonded to the first metal bonding layer M01 to form the first metal layer 101.

[0057] In step S103, with reference to FIGS. 13 and 14, the first substrate B1 is removed.

[0058] Here, after removing the first substrate B1, with reference to FIG. 15, step S103 may further include: thinning the first type of light-emitting layer 102.

[0059] In addition, according to an embodiment, after removing the first substrate B1 or thinning the first type of light-emitting layer 102 and before forming the third metal bonding layer, with reference to FIG. 16, step S103 may further include: forming a micro-gap structure 06 in the first type of light-emitting layer 102. The micro-gap structure 06 is formed by, but not limited to, photolithography and etching. In photolithography, the photolithography pattern is designed according to the size of the micro-gap structure 06. According to an embodiment, the cross-sectional size of the micro-gap structure pattern is not greater than 2 nm. Here, the cross-sectional size of the air gap may be the diameter of the cross-section of the air gap, or the length or width of the cross-section of the air gap.

[0060] In step S104, with reference to FIG. 17, a third metal bonding layer M03 is formed on the first type of light-emitting layer 102, a second type of light-emitting layer 202 is formed on the second substrate B2, and a fourth metal bonding layer M04 is formed on the top of the second type of light-emitting layer 202.

[0061] In step S105, with reference to FIGS. 17 and 18, the second substrate B2 is turned upside down so that the fourth metal bonding layer M04 faces the third metal bonding layer M03, and the fourth metal bonding layer M04 is bonded to the third metal bonding layer M03 to form the second metal layer 201.

[0062] In step S106, with reference to FIGS. 18 and 19, the second substrate B2 is removed.

[0063] Here, after removing the second substrate B2, with reference to FIG. 20, in step S106, the second type of light-emitting layer 202 is thinned.

[0064] According to an embodiment, after removing the second substrate B2 or thinning the second type of light-emitting layer 202, with reference to FIG. 21, in step S106, a micro-gap structure 06 is formed in the second type of light-emitting layer 202. The micro-gap structure 06 is formed by a process similar to that of forming the micro-gap structure 06 in the first type of light-emitting layer 102. Therefore, the process of forming the micro-gap structure 06 in the second type of light-emitting layer 202 will not be described repeatedly.

[0065] Referring back to FIGS. 6 to 10, the process after step S601 according to the embodiments of the present disclosure will be further described below.

[0066] In step S602, referring to FIG. 8, the second-type light-emitting layer 202 and the second metal layer 201 are patterned until a part of the top of the first-type light-emitting layer 102 is exposed, thereby forming a step structure made of the second-type light-emitting layer 202 on the first-type light-emitting layer 102.

[0067] More specifically, the process of patterning the second-type light-emitting layer 202 and the second metal layer 201 can be performed by photolithography and plasma etching. The process of patterning the second-type light-emitting layer 202 and the second metal layer 201 further includes over-etching the top of the first-type light-emitting layer 102. The parameters of the patterning process can be set according to actual needs and will not be limited herein.

[0068] In step S603, referring to FIG. 9, according to the preset first-type light-emitting region A01 and the preset second-type light-emitting region A02, the second-type light-emitting layer 202, the second metal layer 201, the first-type light-emitting layer 102, and the first metal layer 101 are etched, so as to divide the first-type light-emitting layer 102 in the first-type light-emitting region A01 from the first-type light-emitting layer 102 in the second-type light-emitting region A02, and divide the first metal layer 101 in the first-type light-emitting region A01 from the first metal layer 101 in the second-type light-emitting region A02. As a result of step S603, a first-type LED 01 including a first section 101-1 of the first metal layer and a first section 102-1 of the first-type light-emitting layer, and a second-type LED 02 including a second section 101-2 of the first metal layer, a second section 102-2 of the first-type light-emitting layer, a first section 201-1 of the second metal layer, and a second section 202-1 of the second-type light-emitting layer are formed.

[0069] Herein, the process of etching the second-type light-emitting layer 202, the second metal layer 201, the first-type light-emitting layer 102, and the first metal layer 101 is performed by photolithography and etching. The parameters of the etching process can be set according to actual needs.

[0070] According to the embodiment, as a result of step S603, a plurality of multi-color light-emitting pixel units are divided from each other according to the preset pixel unit array. In this way, the pixel units and / or the light-emitting transistors in the pixel unit array can be prepared by one dividing step, which simplifies the process and reduces the production cost, and particularly promotes large-scale production.

[0071] In step S604, referring to FIG. 10, a shared top electrode layer serving as an extraction electrode of the second metal layer 201 is formed on top of the first section 102-1 of the first type of light-emitting layer and the first section 202-1 of the second type of light-emitting layer in the second type of light-emitting region A02.

[0072] FIG. 22 is a flowchart showing details of step S604 in FIG. 6 according to an embodiment of the present disclosure. FIGS. 23 to 25 are cross-sectional views showing structures formed in the steps shown in FIG. 22 according to an embodiment of the present disclosure. Referring to FIG. 22, the specific process of step S604 includes the following steps.

[0073] In step S401, referring to FIG. 23, a part of the first section 202-1 of the second type of light-emitting layer is removed, thereby exposing a part of the first section 201-1 of the second metal layer.

[0074] In step S402, referring to FIG. 24, a first electrical connector 203 is formed on the sidewalls and top of the first section 201-1 of the second metal layer in the second type of light-emitting region A02, on the sidewalls of the second section 102-2 of the first type of light-emitting layer, and on the sidewalls of the second section 101-2 of the first metal layer.

[0075] FIGS. 26 to 27 are cross-sectional views showing structures formed in the steps of manufacturing the first electrical connector 203 according to an embodiment of the present disclosure. In step S402, the first electrical connector 203 is formed through the following specific steps.

[0076] In step S4021, referring to FIG. 24 and FIG. 26, a mask Y is formed to shield the regions without the first electrical connector 203, thereby exposing the top and sidewalls of the first section 201-1 of the second metal layer in the second type of light-emitting region A02, the sidewalls of the second section 102-2 of the first type of light-emitting layer, and the sidewalls of the second section 101-2 of the first metal layer.

[0077] In step S4022, referring to FIG. 27, after completing step S4021, a conductive material 203' is deposited on the substrate 100.

[0078] In step S4023, referring again to FIG. 10, the mask Y and the conductive material 203' on the mask Y are removed, thereby forming the first electrical connector 203 on the top and sidewalls of the first section 201-1 of the second metal layer in the second type of light-emitting region A02, on the sidewalls of the second section 102-2 of the first type of light-emitting layer, and on the sidewalls of the second section 101-2 of the first metal layer.

[0079] The process of manufacturing the shared top electrode layer will be further described below.

[0080] In step S403, referring to FIG. 25, an isolation layer 04 is formed to cover the surfaces of the first type of light-emitting region A01, the second type of light-emitting region A02, and the exposed substrate 100. The isolation layer 04 has openings over a first section 102-1 of the first type of light-emitting layer in the first type of light-emitting region A01 and a first section 202-1 of the second type of light-emitting layer in the second type of light-emitting region A02.

[0081] In step S404, again referring to FIG. 10, after step S403, a continuous shared top electrode layer is formed over the entire substrate 100, for example, by deposition. The shared top electrode layer formed in the openings is connected to the first section 102-1 of the first type of light-emitting layer in the first type of light-emitting region A01 and the first section 202-1 of the second type of light-emitting layer in the second type of light-emitting region A02.

[0082] FIG. 28 shows the structure of a multicolor light-emitting pixel unit according to an embodiment of the present disclosure text, where the multicolor light-emitting pixel unit has a micro-gap structure in a first type of light-emitting layer 102 and a second type of light-emitting layer 202.

[0083] FIG. 29 is a flowchart showing a method of manufacturing the multicolor light-emitting pixel unit 3000 shown in FIG. 3 according to an embodiment of the present disclosure text. FIGS. 30 to 34 are cross-sectional views showing the structures formed in the steps shown in FIG. 6 according to an embodiment of the present disclosure text. Referring to FIG. 29, the method of manufacturing the multicolor light-emitting pixel unit 3000 shown in FIG. 3 includes the following steps.

[0084] In step S701, referring to FIG. 30, a stacked structure including a first metal layer 101, a first type of light-emitting layer 102, a second metal layer 201, a second type of light-emitting layer 202, a third metal layer 301, and a third type of light-emitting layer 302 is formed on the substrate 100 in a bottom-to-top order. In other words, the first type of light-emitting layer 102, the second type of light-emitting layer 202, and the third type of light-emitting layer 302 are stacked on the substrate 100 from bottom to top. The first metal layer 101 is formed at the bottom of the first type of light-emitting layer 102. The second metal layer 201 is formed at the bottom of the second type of light-emitting layer 202. The third metal layer 301 is formed at the bottom of the third type of light-emitting layer 302. The second metal layer 201 is disposed between the first type of light-emitting layer 102 and the second type of light-emitting layer 202. The third metal layer 301 is disposed between the second type of light-emitting layer 202 and the third type of light-emitting layer 302.

[0085] Figure 35 is a flowchart showing the details of step S701 in FIG. 29 according to an embodiment of the present disclosure. Referring to FIG. 35 in conjunction with FIG. 30, step S701 further includes the following steps. It should be noted that the structures formed in steps S801 to S809 of this embodiment are not shown in the drawings. However, those skilled in the art can refer to steps S101 to S109 of the above embodiment to understand steps S801 to S809 of this embodiment.

[0086] In step S801, a first metal bonding layer is formed on the substrate 100, a first type of light-emitting layer 102 is formed on the first substrate, and a second metal bonding layer is formed on top of the first type of light-emitting layer 102.

[0087] More specifically, the first metal bonding layer can be prepared by, but not limited to, physical vapor deposition (such as evaporation, sputtering, etc.). The material of the first substrate is designed according to the first type of light-emitting layer 10. For example, the first substrate can be a gallium nitride (GaN) substrate. The first type of light-emitting layer 102 can be formed by, but not limited to, epitaxial growth on the first substrate. The second metal bonding layer can be prepared by, but not limited to, physical vapor deposition (such as evaporation).

[0088] In step S802, the first substrate is inverted up and down so that the second metal bonding layer faces the first metal bonding layer, and then the second metal bonding layer is bonded to the first metal bonding layer to form the first metal layer 101.

[0089] In step S803, the first substrate is removed.

[0090] Here, after removing the first substrate, step S803 may further include: thinning the first type of light-emitting layer 102. In addition, after removing the first substrate or thinning the first type of light-emitting layer 102, and before forming the third metal bonding layer, referring to FIG. 36, step S803 may further include: forming a micro-gap structure 06 in the first type of light-emitting layer 102. The micro-gap structure 06 is formed by, but not limited to, photolithography and etching. In photolithography, the photolithography pattern is designed according to the size of the micro-gap structure 06. According to the embodiment, the cross-sectional size of the micro-gap structure pattern is not greater than 2 nm.

[0091] In step S804, a third metal bonding layer is formed on the first type of light-emitting layer 102, a second type of light-emitting layer 202 is formed on the second substrate, and a fourth metal bonding layer is formed on top of the second type of light-emitting layer 202.

[0092] In step S805, the second substrate is inverted up and down so that the fourth metal bonding layer faces the third metal bonding layer, and then the fourth metal bonding layer is bonded to the third metal bonding layer to form the second metal layer 201.

[0093] In step S806, the second substrate is removed.

[0094] Here, after removing the second substrate, step S106 may further include: thinning the second type of light-emitting layer 202. Further, after removing the second substrate or thinning the second type of light-emitting layer 202, referring to FIG. 36, step S106 further includes: forming a micro-gap structure 06 in the second type of light-emitting layer 202. The micro-gap structure 06 can be formed using a process similar to the above-described process of forming the micro-gap structure 06. Therefore, the process of forming the micro-gap structure 06 will not be described repeatedly.

[0095] In step S807, a fifth metal bonding layer is formed on the second type of light-emitting layer 202, a third type of light-emitting layer 302 is formed on the third substrate, and a sixth metal bonding layer is formed on top of the third type of light-emitting layer 302.

[0096] In step S808, the third substrate is inverted up and down so that the sixth metal bonding layer faces the fifth metal bonding layer, and then the sixth metal bonding layer is bonded to the fifth metal bonding layer to form a third metal layer 301.

[0097] In step S809, the third substrate is removed.

[0098] Here, after removing the third substrate, step S109 may further include: thinning the third type of light-emitting layer 302. Further, after removing the third substrate or thinning the third type of light-emitting layer 302, referring to FIG. 36, step S109 further includes: forming a micro-gap structure 06 in the third type of light-emitting layer 302. The micro-gap structure 06 can be formed using a process similar to the above-described process of forming the micro-gap structure 06. Therefore, the process of forming the micro-gap structure 06 will not be described repeatedly.

[0099] FIG. 36 shows the micro-gap structure 06 in the first type of light-emitting layer 102, the second type of light-emitting layer 202, and the third type of light-emitting layer 302.

[0100] Returning to FIGS. 30 to 34, the process after step S701 will be further described below.

[0101] In step S702, referring to FIG. 31, the third type of light-emitting layer 302 and the third metal layer 301 are patterned until a part of the top of the second type of light-emitting layer 202 is exposed, thereby forming a stepped structure made of the third type of light-emitting layer 302 on the second type of light-emitting layer 202.

[0102] More specifically, the step structure includes a third type of light-emitting layer 302 and a third metal layer 301. The process of patterning the third type of light-emitting layer 302 and the third metal layer 301 further includes over-etching the top of the first type of light-emitting layer 102.

[0103] In step S703, referring to FIG. 32, the second type of light-emitting layer 202 and the second metal layer 201 are further patterned until a part of the top of the first type of light-emitting layer 102 is exposed, thereby forming a step structure made of the second type of light-emitting layer 202 on the first type of light-emitting layer 102.

[0104] More specifically, the step structure is made of the second type of light-emitting layer 202 and the second metal layer 201. The patterning process can be performed by photolithography and plasma etching. The process of patterning the second type of light-emitting layer 202 and the second metal layer 201 further includes over-etching the top of the first type of light-emitting layer 102. The parameters of the patterning process can be set according to actual needs and will not be limited herein.

[0105] In step S704, referring to FIG. 33, the third-type light-emitting layer 302, the third metal layer 301, the second-type light-emitting layer 202, the second metal layer 201, the first-type light-emitting layer 102, and the first metal layer 101 are etched according to a preset first-type light-emitting region A01, a preset second-type light-emitting region A02, and a preset third-type light-emitting region A03, so as to divide the first-type light-emitting layer 102 in the first-type light-emitting region A01 from the first-type light-emitting layers in the second-type light-emitting region A02 and the third-type light-emitting region A03, divide the first metal layer 101 in the first-type light-emitting region A01 from the first metal layers in the second-type light-emitting region A02 and the third-type light-emitting region A03, divide the second-type light-emitting layer 202 in the second-type light-emitting region A02 from the second-type light-emitting layers in the third-type light-emitting region A03, and divide the second metal layer 201 in the second-type light-emitting region A02 from the second metal layers in the third-type light-emitting region A03. As a result of step S704, the first-type LED 01 including the first section 101-1 of the first metal layer and the first section 102-1 of the first-type light-emitting layer is formed; the second-type LED 02 including the second section 101-2 of the first metal layer, the second section 102-2 of the first-type light-emitting layer, the first section 201-1 of the second metal layer, and the first section 202-1 of the second-type light-emitting layer is formed; and the third-type LED 03 including the third section 101-3 of the first metal layer, the third section 102-3 of the first-type light-emitting layer, the second section 201-2 of the second metal layer, the second section 202-2 of the second-type light-emitting layer, the first section 301-1 of the third metal layer, and the first section 302-1 of the third-type light-emitting layer is formed.

[0106] Here, the etching process is performed by photolithography and the etching process, and its parameters can be set according to actual needs.

[0107] According to the embodiment, as a result of step S704, a plurality of multicolor light-emitting pixel units are divided from each other according to a preset pixel unit array. Therefore, the pixel units and / or the light-emitting transistors in the pixel unit array can be fabricated in one dividing step, which simplifies the process and reduces the production cost, especially facilitating mass production.

[0108] In step S705, referring to FIG. 34, a shared top electrode layer serving as the lead-out electrode of the first section 201-1 of the second metal layer and the lead-out electrode of the first section 301-1 of the third metal layer is formed on the tops of the first section 102-1 of the first-type light-emitting layer, the first section 202-1 of the second-type light-emitting layer, and the first section 302-1 in the third-type light-emitting layer.

[0109] FIG. 37 is a flowchart showing details of step S705 in FIG. 29 according to an embodiment of the present disclosure. FIGS. 38 to 40 are cross-sectional views showing structures formed in the steps shown in FIG. 37. Referring to FIG. 37, step S705 further includes the following steps.

[0110] In step S501, referring to FIG. 38, a part of the first section 302-1 of the third type of light-emitting layer and a part of the first section 202-1 of the second type of light-emitting layer are removed, thereby exposing a part of the first section 201-1 of the second metal layer and a part of the first section 301-1 of the third metal layer.

[0111] In step S502, referring to FIG. 39, a first electrical connector 203 is formed on the sidewalls and top of the first section 201-1 of the second metal layer in the second type of light-emitting region A02, on the sidewalls of the second section 102-2 of the first type of light-emitting layer, and on the sidewalls of the second section 101-2 of the first metal layer, and a second electrical connector 303 is formed on the top and sidewalls of the first section 301-1 of the third metal layer in the third type of light-emitting region A03, on the sidewalls of the second section 202-2 of the second type of light-emitting layer, on the sidewalls of the second section 201-2 of the second metal layer, on the sidewalls of the third section 102-3 of the first type of light-emitting layer, and on the sidewalls of the third section 101-3 of the first metal layer.

[0112] More specifically, referring to FIG. 39, the process of manufacturing the first electrical connector 203 and the second electrical connector 303 further includes the following steps. It should be noted that the following steps S5021 to S5023 are not shown in the drawings, but those skilled in the art can understand steps S5021 to S5023 by referring to steps S4021 to S4023 of the above embodiments.

[0113] In step S5021, a mask is formed on the substrate 100 to shield the regions without the first electrical connector 203 and the second electrical connector 303, thereby exposing the top and sidewalls of the first section 201-1 of the second metal layer in the second type of light-emitting region A02, the sidewalls of the second section 102-2 of the first type of light-emitting layer, and the sidewalls of the second section 101-2 of the first metal layer, and exposing the top and sidewalls of the first section 301-1 of the third metal layer in the third type of light-emitting region A03, the sidewalls of the second section 202-2 of the second type of light-emitting layer, the sidewalls of the second section 201-2 of the second metal layer, the sidewalls of the third section 102-3 of the first type of light-emitting layer, and the sidewalls of the third section 101-3 of the first metal layer.

[0114] In step S5022, after completing step S5021, a conductive material is deposited on the substrate 100.

[0115] In step S5023, referring to FIG. 39, the mask and the conductive material on the mask are removed, so as to form a first electrical connector 203 on the top and sidewalls of the first section 201-1 of the second metal layer in the second type of light-emitting region A02, on the sidewalls of the second section 102-2 of the first type of light-emitting layer, and on the sidewalls of the second section 101-2 of the first metal layer, and to form a second electrical connector 303 on the top and sidewalls of the first section 301-1 of the third metal layer in the third type of light-emitting region A03, on the sidewalls of the second section 202-2 of the second type of light-emitting layer, on the sidewalls of the second section 201-2 of the second metal layer, on the sidewalls of the third section 102-3 of the first type of light-emitting layer, and on the sidewalls of the third section 101-3 of the first metal layer.

[0116] The process of manufacturing the shared top electrode layer will be further described below.

[0117] In step S503, referring to FIG. 40, an isolation layer 04 is formed to cover the surfaces of the first type of light-emitting region A01, the second type of light-emitting region A02, the third type of light-emitting region A03, and the exposed substrate 100. The isolation layer 04 has openings on the first section 102-1 of the first type of light-emitting layer, on the first section 202-1 of the second type of light-emitting layer, and on the first section 302-1 of the third type of light-emitting layer.

[0118] In step S504, referring again to FIG. 34, after step S503, a continuous shared top electrode layer is formed on the entire substrate 100. The shared top electrode layer deposited in the openings is connected to the first section 102-1 of the first type of light-emitting layer, connected to the first section 202-1 of the second type of light-emitting layer, and connected to the first section of the third type of light-emitting layer 302.

[0119] As mentioned above, in the method of manufacturing a multi-color light-emitting pixel unit according to an embodiment of the present disclosure, since the film deposition processes of each type of LED can be performed simultaneously, the LEDs can be prepared simultaneously without being prepared separately, thereby simplifying the processes of manufacturing the multi-color light-emitting pixel unit and the micro-LED display panel and facilitating mass production. Due to the manufacturing method according to an embodiment of the present disclosure, different types of LEDs are arranged side by side on the same substrate with a short distance between them. Therefore, the sizes of the LEDs and the display panel made of the LEDs can be reduced. For example, the size of each LED can be 40 μm × 40 μm. In addition, the tops of different types of LEDs are not on the same horizontal plane. That is, the heights of different types of LEDs are different, so that different types of light-emitting layers are exposed on the tops of different types of LEDs, thus ensuring the light-emitting area, improving the light-emitting efficiency of each LED, and improving the integration of various LEDs. The micro-LED display panel formed by the pixel unit according to an embodiment of the present disclosure has a clear picture display and high resolution. In addition, since the electrical connector connects each metal layer in the M-type LED, the M-type light-emitting layer (which is the top light-emitting layer) in the M-type LED can emit light, while the other light-emitting layers in the M-type LED are short-circuited because the metal layers provided on both sides of each other light-emitting layer are electrically connected to each other. For example, in the M-type LED, the first-type light-emitting layer is short-circuited because the first-type metal layer and the second-type metal layer provided on both sides of the first-type light-emitting layer are electrically connected to each other; the second-type light-emitting layer is short-circuited because the second-type metal layer and the third-type metal layer provided on both sides of the second-type light-emitting layer are electrically connected to each other; and so on. Therefore, various types of LEDs emit light separately without interfering with each other. In addition, the micro-gaps in the light-emitting layer can release the stress inside the light-emitting layer and avoid its warping without affecting the light-emitting efficiency of the light-emitting layer, thus improving the product yield.

[0120] Although the present invention has been specifically shown and described with reference to its preferred embodiments, those skilled in the art will understand that various changes in form and detail may be made herein without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A multicolor light-emitting pixel unit, comprising: A substrate; A bottom conductive layer formed on the substrate; A light-emitting layer formed on the bottom conductive layer; A top isolation layer covering the top surface of the light-emitting layer and the side surfaces of the light-emitting layer and the bottom conductive layer; And A top conductive layer covering the top isolation layer, Wherein the light-emitting layer includes a plurality of micro-gap structures.

2. The multicolor light-emitting pixel unit according to claim 1, wherein each of the micro-gap structures in the micro-gap structure extends in a direction perpendicular to the substrate and passes through the light-emitting layer.

3. The multicolor light-emitting pixel unit according to claim 1, wherein each of the micro-gap structures in the micro-gap structure is an air gap.

4. The multicolor light-emitting pixel unit according to claim 3, wherein the cross-sectional size of each of the air gaps in the air gap is not greater than 2 nm.

5. The multicolor light-emitting pixel unit according to claim 1, wherein each of the micro-gap structures in the micro-gap structure is sealed between the top conductive layer and the bottom conductive layer.

6. The multicolor light-emitting pixel unit according to claim 1, wherein the light-emitting layer is a first light-emitting layer, and the multicolor light-emitting pixel unit further includes: A second light-emitting layer formed between the first light-emitting layer and the bottom conductive layer.

7. The multicolor light-emitting pixel unit according to claim 6, wherein the plurality of micro-gap structures included in the first light-emitting layer are a first plurality of micro-gap structures, The second light-emitting layer includes a second plurality of micro-gap structures.

8. The multicolor light-emitting pixel unit according to claim 7, wherein the first plurality of micro-gap structures are not vertically aligned with the second plurality of micro-gap structures.

9. The multicolor light-emitting pixel unit according to claim 7, further comprising: A metal layer formed between the first light-emitting layer and the second light-emitting layer.

10. The multicolor light-emitting pixel unit according to claim 9, wherein The first plurality of micro-gap structures are sealed between the top isolation layer and the metal layer, and The second plurality of micro-gap structures are sealed between the metal layer and the bottom conductive layer.

11. The multicolor light-emitting pixel unit according to claim 6, wherein the multicolor light-emitting pixel unit further includes: A third light-emitting layer formed between the second light-emitting layer and the bottom conductive layer.

12. The multicolor light-emitting pixel unit according to claim 11, wherein at least one of the second light-emitting layer and the third light-emitting layer includes a plurality of micro-gap structures.

13. The multicolor light-emitting pixel unit according to claim 11, wherein the plurality of micro-gap structures included in the first light-emitting layer are a first plurality of micro-gap structures, The second light-emitting layer includes a second plurality of micro-gap structures, and The third light-emitting layer includes a third plurality of micro-gap structures.

14. The multicolor light-emitting pixel unit according to claim 13, wherein The first plurality of micro-gap structures are not vertically aligned with the second plurality of micro-gap structures, and The second plurality of micro-gap structures are not vertically aligned with the third plurality of micro-gap structures.

15. The multicolor light-emitting pixel unit according to claim 13, further comprising: a first metal layer formed between the first light-emitting layer and the second light-emitting layer; and a second metal layer formed between the second light-emitting layer and the third light-emitting layer.

16. The multicolor light-emitting pixel unit according to claim 15, wherein the first plurality of micro-gap structures are sealed between the top isolation layer and the first metal layer, the second plurality of micro-gap structures are sealed between the first metal layer and the second metal layer, and the third plurality of micro-gap structures are sealed between the second metal layer and the bottom conductive layer.

17. A micro display panel, comprising the multicolor light-emitting pixel unit according to claim 1.

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