Multi-color LED pixel units and micro-LED display panels

Abstract

A multi-color luminescent pixel unit (3000) comprises a substrate (100) and a luminescent transistor formed on the substrate (100). The luminescent transistor comprises: a bottom conductive layer formed on the substrate (100) and a top conductive layer formed above the bottom conductive layer; an upper luminescent layer formed between the top conductive layer and the bottom conductive layer; at least one lower luminescent layer formed between the upper luminescent layer and the bottom conductive layer; and an electrical connector (303) electrically connecting the at least one lower luminescent layer and the bottom conductive layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based upon and claims the benefit of priority from U.S. patent application Ser. No. 16 / 567,123, filed Sep. 11, 2019. The contents of the aforementioned application are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates generally 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 converts electrical energy into light energy. A conventional light-emitting diode includes a PN junction with unidirectional conduction. Under 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 produces spontaneous emission of excitation light. 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 light of different wavelengths from ultraviolet light to infrared light, thereby producing multi-color LEDs.

[0005] Multicolor LEDs that emit white light or other colors have a wide range of applications, most of which are used in the display field. Conventional LED display panels are formed by assembling single-color LEDs one by one on a substrate. Methods for assembling single-color LEDs include: bonding the LEDs to an interconnect layer using metal bonding processes or other processes through the LED's metal wires or connecting electrodes. The process of assembling LEDs of other colors is not performed until the process of assembling the single-color LEDs is completed, resulting in a complex process, increased processing difficulty, and increased production costs. In addition, multicolor 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 and a light-emitting transistor formed on the substrate. The light-emitting transistor includes: a bottom conductive layer formed on the substrate; a top conductive layer formed above the bottom conductive layer; an upper light-emitting layer formed between the top conductive layer and the bottom conductive layer; at least one lower light-emitting layer formed between the upper light-emitting layer and the bottom conductive layer; and an electrical connector electrically connecting the at least one lower light-emitting layer and the bottom conductive layer.

[0007] According to another aspect of the present disclosure, a micro display panel is provided, wherein 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] FIG2 is a cross-sectional view showing a multi-color light-emitting pixel unit according to an embodiment of the present disclosure.

[0010] FIG3 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] FIG5 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 flow chart 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] 7 to 10 are cross-sectional views illustrating structures formed in steps of the method of 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] 12 to 21 are cross-sectional views showing the structure formed in the 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] 23 to 25 are cross-sectional views showing the structure formed in the steps of FIG. 22 according to an embodiment of the present disclosure.

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

[0020] FIG28 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 flow chart 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] 30-34 are cross-sectional views illustrating structures formed in steps of the method of 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] 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] 38 to 40 are cross-sectional views showing the structure formed in the steps of FIG. 37 according to an embodiment of the present disclosure. DETAILED DESCRIPTION

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

[0028] Hereinafter, the present disclosure will be further described through embodiments of the present disclosure in conjunction with Figures 1 to 40. It should be noted that all drawings are in very simplified form and not in exact proportions only for the purpose of conveniently and clearly explaining the embodiments of the present disclosure.

[0029] The multi-color light-emitting pixel unit disclosed in this article includes at least one type of light-emitting transistor, or several types of light-emitting transistors. Various types of light-emitting transistors include an upper conductive layer, a bottom conductive layer, and a light-emitting layer between the upper conductive layer and the bottom conductive layer. All 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 a multilayer. The intermediate layer can be arranged between two light-emitting layers of the multiple light-emitting layers in the same light-emitting diode. Assume that the multi-color light-emitting pixel unit includes first to M-th types of light-emitting transistors, where M is an integer and not less than two. Each of the first to M-th types of light-emitting transistors includes at least the same type of light-emitting layer. For example, each of the first to M-th types of light-emitting transistors includes a first type of light-emitting layer. Any of the second to M-th types 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-mentioned pixel units arranged in a matrix.

[0030] In some embodiments, the light-emitting transistor can be at least one of a light-emitting diode (LED), a Schottky light-emitting transistor, and the like. The top conductive layer of the light-emitting transistor is, but is not limited to, a transparent conductive layer, and the bottom conductive layer of the light-emitting transistor is, but is not limited to, a metal layer. In the following, an LED is used as an example of a 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] FIG1 is a cross-sectional view illustrating a multi-color light-emitting pixel unit 1000 according to an embodiment of the present disclosure. Referring to FIG1 , multi-color light-emitting pixel unit 1000 includes at least a first-type LED 01 and a second-type LED 02 arranged side by side on a substrate 100. The top of the first-type LED 01 is not at the same level as the top of the second-type LED 02. The first-type LED 01 and the second-type LED 02 are of different types. As shown in FIG1 , the top of the first-type LED 01 is lower than the top of the second-type LED 02. According to an embodiment, the first-type 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 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. Furthermore, the light-emitting area of ​​the first-type LED 01 is different from the light-emitting area of ​​the second-type LED 02. For example, the first-type LED 01 is a red LED and the second-type LED 02 is a green LED, and the light-emitting area of ​​the red LED is different from the light-emitting area of ​​the green LED. Furthermore, depending on the different colors that may be required, the light emitting area of ​​the green LED may be smaller than that of the red LED.

[0032] Furthermore, an isolation structure 07 is disposed between the first type LED and the second type LED. In the embodiment shown in FIG1 , the isolation structure 07 between the first type LED 01 and the second type LED 02 is an isolation trench. Multi-color light-emitting pixel unit 1000 includes a first metal layer, a first type light-emitting layer, a second metal layer, and a second type light-emitting layer. As shown in FIG1 , the first type LED 01 includes, from bottom to top, at least a first segment 101-1 of the first metal layer and a first segment 102-1 of the first type light-emitting layer. The first segment 101-1 of the first metal layer constitutes the bottom conductive layer of the first type LED 01. The second type LED 02 includes, from bottom to top, at least a second segment 101-2 of the first metal layer, a second segment 102-2 of the first type light-emitting layer, a first segment 201-1 of the second metal layer, and a first segment 202-2 of the second type light-emitting layer, as well as a first electrical connector 203. First segment 101-1 of the first metal layer and second segment 101-2 of the first metal layer are electrically connected to substrate 100. Isolation structure 07 isolates first segment 101-1 of the first metal layer in first-type LED 01 from second segment 101-2 of the first metal layer in second-type LED 02. Isolation structure 07 also isolates first segment 102-1 of the first-type light-emitting layer in first-type LED 01 from second segment 102-2 of the first-type light-emitting layer in second-type LED 02. Furthermore, to simplify the manufacturing process, first segment 201-1 of the second metal layer, second segment 102-2 of the first-type light-emitting layer, and second segment 101-2 of the first metal layer in second-type LED 02 are electrically connected to each other via first electrical connector 203. According to one embodiment, first electrical connector 203 may be attached to and contact a portion or all of the sidewall surface of second-type LED 02. Alternatively, first electrical connector 203 may be attached to and contact only the surface of first segment 201-1 of the second metal layer and second segment 101-2 of the first metal layer in second type LED 02. Alternatively, first electrical connector 203 may be formed as a conductive side arm that is attached to and contacts the sidewalls of first segment 201-1 of the second metal layer, second segment 102-2 of the first type light-emitting layer, and second segment 101-2 of the first metal layer. Electrical connector 203 between second segment 101-2 of the first metal layer and first segment 201-1 of the second metal layer in second type LED 02 may have other shapes, such as a curve. In the embodiment illustrated in FIG. 1 , first electrical connector 203 is attached to the sidewall of second type LED 02 such that first electrical connector 203 conforms to the surface topography of the sidewall of second type LED 02.

[0033] 1 , a top insulating layer 04 and a top transparent conductive layer 05 are disposed on the first segment 102-1 of the first type of light-emitting layer in the first type of LED 01 and the first segment 202-1 of the second type of light-emitting layer in the second type of LED 02. Top insulating layer 04 covers the first segment 102-1 of the first type of light-emitting layer, the first segment 202-1 of the second type of light-emitting layer, and the exposed substrate 100. Top insulating layer 04 has an opening that exposes portions of the top surfaces of the first segment 102-1 of the first type of light-emitting layer and the first segment 202-1 of the second type of light-emitting layer. Top transparent conductive layer 05 covers top insulating layer 04 and is formed in the opening of top insulating layer 04, thereby contacting the exposed top surfaces of the first segment 102-1 of the first type of light-emitting layer and the first segment 202-1 of the second type of light-emitting layer via the opening.

[0034] Substrate 100 is an integrated circuit (IC) substrate. The IC substrate includes an interconnect layer that electrically connects first segment 101-1 of the first metal layer in first-type LED 01 and second segment 101-2 of the first metal layer in second-type LED 02. Because first electrical connector 203 is connected to second segment 101-2 of the first metal layer in second-type LED 02, first electrical connector 203 is connected to the interconnect layer in substrate 100. Furthermore, referring to FIG1 , the bottom of first electrical connector 203 extends to substrate 100 to connect to the interconnect layer. The IC substrate includes at least a driver circuit. The driver circuit controls each LED individually.

[0035] FIG2 is a cross-sectional view illustrating a multi-color light-emitting pixel unit 2000 according to an embodiment of the present disclosure. Referring to FIG2 , multi-color light-emitting pixel unit 2000 includes at least a first-type LED 01, a second-type LED 02, and a third-type LED 03, arranged on the same substrate 100. The third-type LED 03 is different from the first-type LED 01 and the second-type LED 02. Here, the first-type 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 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 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 LED 01, a green LED is selected as the second-type LED 02, and a blue LED is selected as the third-type LED 03. Referring to FIG2 , the height of the third-type LED 03 is different from that of the first-type LED 01. Furthermore, 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 FIG3 .

[0036] In multi-color light-emitting pixel unit 2000, the structures of first-type LED 01 and second-type LED 02 are identical to those of first-type LED 01 and second-type LED 02 in multi-color light-emitting pixel unit 2000, and therefore their detailed descriptions are not repeated. Third-type LED 03 in multi-color light-emitting pixel unit 2000 includes, in order from bottom to top, at least a third segment 101-3 of the first metal layer, a third segment 102-3 of the first-type light-emitting layer, a first segment 301-1 of the third metal layer, and a first segment 302-1 of the third-type light-emitting layer, as well as a second electrical connector 303 connecting third segment 101-3 of the first metal layer and first segment 301-1 of the third metal layer. Multi-color light-emitting pixel unit 2000 further includes a top isolation layer 04, which covers first-type LED 01, second-type LED 02, and third-type LED 03 and has an opening that exposes a portion of the first segment of the first-type light-emitting layer 102-1, a portion of the first segment 202-1 of the second-type light-emitting layer, and a portion of the first segment 302-1 of the third-type light-emitting layer in first-type LED 01. A top electrode layer 05 is formed on top of top isolation layer 04 and contacts first segment 102-1 of the first-type light-emitting layer, first segment 202-1 of the second-type light-emitting layer, and first segment 302-1 of the third-type light-emitting layer via the opening in top isolation layer 04.

[0037] FIG3 is a cross-sectional view showing a multi-color light-emitting pixel unit 3000 according to an embodiment of the present disclosure. Referring to FIG3 , in the multi-color light-emitting pixel unit 3000, the top of the third type LED 03 is higher than the top of the second type LED 02, and the height of the first type LED is different from the height of the second type LED 03.

[0038] FIG4 is a top view of a multi-color light-emitting pixel unit 4000 according to an embodiment of the present disclosure. Multi-color light-emitting pixel unit 4000 may be the multi-color light-emitting pixel unit 2000 shown in FIG2 or the multi-color light-emitting pixel unit 3000 shown in FIG3. FIG4 illustrates the arrangement of three types of LEDs (LEDs) O1, O2, and O3 within the pixel unit, but the present disclosure also encompasses other arrangements, such as a matrix. Here, the light-emitting area of ​​the third type of LED O3 differs from the light-emitting area of ​​the first type of LED O1 and differs from the light-emitting area of ​​the second type of LED O2. For example, the first type of LED O1 is a red LED, the second type of LED O2 is a green LED, and the third type of LED O3 is a blue LED. The light-emitting area of ​​each of the first type of LED O1, the second type of LED O2, and the third type of LED O3 can be determined based on the color of light to be emitted by the multi-color light-emitting pixel unit 4000. When white light is desired, the light-emitting area of ​​the red LED is larger than that of the green LED, and the light-emitting area of ​​the blue LED is larger than that of the green LED. As shown in FIG4 , 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 lighting effect.

[0039] Referring back to FIG3 , an isolation structure 07 is disposed between two of the first-type LED 01, the second-type LED 02, and the third-type LED 03. The isolation structure is an isolation trench. The first-type LED 01, the second-type LED 02, and the third-type LED 03 are formed by a first metal layer 101, a first-type light-emitting layer 102, a second metal layer 201, a second-type light-emitting layer 202, a third metal layer 301, and a third-type light-emitting layer 302. The first-type LED 01 and the second-type LED 02 in FIG3 are identical to the first-type LED 01 and the second-type LED 02 in FIG2 . Specifically, as shown in FIG3 , the first-type LED 01 includes, from bottom to top, at least a first segment 101-1 of the first metal layer and a first segment 102-1 of the first-type light-emitting layer. The second type of LED 02 includes, in order from bottom to top, at least the second segment 101-2 of the first metal layer, the second segment 102-2 of the first type of light-emitting layer, the first segment 201-1 of the second metal layer, the first segment 202-1 of the second type of light-emitting layer, and a first electrical connector 203. The third type of LED 03 includes, in order from bottom to top, at least the third segment 101-3 of the first metal layer, the third segment 102-3 of the first type of light-emitting layer, the second segment 201-2 of the second metal layer, the second segment 202-2 of the second type of light-emitting layer, the first segment 301-1 of the third metal layer, the first segment 302-1 of the third type of light-emitting layer, and a second electrical connector 303. As shown in FIG. 3 , the first segment 101-1 of the first metal layer, the second segment 101-2 of the first metal layer, and the third segment 101-3 of the first metal layer are electrically connected to the substrate 100. The first electrical connector 203 in the second type LED 02 electrically connects the first segment 201-1 of the second metal layer with the second segment 101-2 of the first metal layer. The second electrical connector 303 in the third type LED 03 electrically connects the first segment 301-1 of the third metal layer with the second segment 201-2 of the second metal layer and the third segment 101-3 of the first metal layer.The isolation structure 07 isolates the first segment 101-1 of the first metal layer in the first type of LED 01 from the second segment 101-2 of the first metal layer in the second type of LED 02 and the third segment 101-3 of the first metal layer in the third type of LED 03, isolates the first segment 102-1 of the first type of light-emitting layer in the first type of LED 01 from the second segment 102-2 of the first type of light-emitting layer in the second type of LED 02 and the third segment 102-3 of the first type of light-emitting layer in the third type of LED 03, isolates the first segment 201-1 of the second metal layer in the second type of LED 02 from the second segment 201-2 of the second metal layer in the third type of LED 03, and isolates the first segment 202-1 of the second type of light-emitting layer in the second type of LED 02 from the second segment 202-2 of the second type of light-emitting layer in the third type of LED 03. It should be noted that first electrical connector 203 is used to connect second segment 102-2 of the first type of light-emitting layer in second type LED 02 with second segment 101-2 of the first metal layer, while second electrical connector 303 is used to connect second segment 202-2 of the second type of light-emitting layer and third segment 102-3 of the first type of light-emitting layer in third type LED 03 with third segment 101-3 of the first metal layer. Therefore, to simplify the manufacturing process, in the same manner as in FIG1 , first electrical connector 203 also connects second segment 102-2 of the first type of light-emitting layer with second segment 101-2 of the first metal layer. That is, in second type LED 02, first electrical connector 203 connects first segment 201-1 of the second metal layer and second segment 102-2 of the first type of light-emitting layer with second segment 101-2 of the first metal layer. Second electrical connector 303 also connects second segment 202-2 of the second type of light-emitting layer with third segment 101-3 of the first metal layer. That is, in the third type of LED 03, the second electrical connector 303 connects the first segment 301-1 of the third metal layer, the second segment 202-2 of the second type of light-emitting layer, and the second segment 201-2 of the second metal layer to the third segment 101-3 of the first metal layer. Alternatively, the second electrical connector 303 also connects the second segment 202-2 of the second type of light-emitting layer and the third segment 102-3 of the first type of light-emitting layer to the third segment 101-3 of the first metal layer. That is, in the third type of LED 03, the second electrical connector 303 connects the first segment 301-1 of the third metal layer, the second segment 202-2 of the second type of light-emitting layer, the second segment 201-2 of the second metal layer, and the third segment 102-3 of the first type of light-emitting layer to the third segment 101-3 of the first metal layer.Furthermore, the bottoms of the first and second electrical connectors 203 and 303 respectively and directly contact the substrate 100, thereby simplifying the manufacturing process. It should be noted that the first and second electrical connectors 203 and 303 are made of a conductive metal. In one 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 red LED 01, a voltage applied between the top transparent conductive layer 05 and the first segment 101-1 of the first metal layer is applied to the first segment 102-1 of the red light-emitting layer. Consequently, the first segment 102-1 of the red light-emitting layer in red LED 01 emits red light. In green LED 02, the first electrical connector 203 electrically connects the second segment 102-2 of the red light-emitting layer to the second segment 101-2 of the first metal layer, so that the voltage applied between the top transparent conductive layer 05 and the second segment 101-2 of the first metal layer is applied only to the first segment 202-1 of the green light-emitting layer. As a result, only the first segment 202-1 of the green light-emitting layer in green LED 02 emits green light, while the second segment 102-2 of the red light-emitting layer in green LED 02 does not emit light. In the third type of LED 03, the second electrical connector 303 electrically connects the third segment 102-3 of the red light-emitting layer and the second segment 202-2 of the green light-emitting layer to the third segment 101-3 of the first metal layer, so that the voltage applied between the top transparent conductive layer 05 and the third segment 101-3 of the first metal layer is applied only to the first segment 302-1 of the blue light-emitting layer. As a result, only the first segment 302-1 of the blue light-emitting layer in blue LED 03 emits blue light, while the third segment 102-3 of the red light-emitting layer and the second segment 202-2 of the green light-emitting layer in blue LED 03 do not emit light.

[0041] Referring again to FIG. 3 , a top insulating layer 04 and a top transparent conductive layer 05 are disposed over the first type LED 01, the second type LED 02, and the third type LED 03. The top insulating layer 04 covers the first segment 102-1 of the first type light-emitting layer, the first segment 202-1 of the second type light-emitting layer, the first segment 302-1 of the third type light-emitting layer, and the exposed substrate 100. An opening is disposed in the top insulating layer 04 to expose portions of the top surfaces of the first segment 102-1 of the first type light-emitting layer, the first segment 202-1 of the second type light-emitting layer, and the first segment 302-1 of the third type light-emitting layer. The top transparent conductive layer 05 covers the top insulating layer 04 and is formed in the opening in the top insulating layer 04, thereby contacting the exposed top surfaces of the first segment 102-1 of the first type light-emitting layer, the first segment 202-1 of the second type light-emitting layer, and the first segment 302-1 of the third type 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 FIG1 and will not be repeated here. It should be noted that the interconnect 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 driver circuit in the IC substrate 100 controls each LED separately.

[0043] In the multi-color light-emitting pixel units 1000 to 4000 in Figures 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 Figure 1, the first-type light-emitting layer 102 may have a micro-gap structure, or the second-type light-emitting layer 202 may have a micro-gap structure, or both the first-type light-emitting layer 102 and the second-type light-emitting layer 202 may have a micro-gap structure. As another example, in the multi-color luminescent pixel unit 3000 shown in FIG3 , the first type of luminescent layer 102 may have a microgap structure, or the second type of luminescent layer 202 may have a microgap structure, or the third type of luminescent layer 302 may have a microgap structure, or both the first type of luminescent layer 102 and the second type of luminescent layer 202 may have a microgap structure, or both the second type of luminescent layer 202 and the third type of luminescent layer 302 may have a microgap structure, or both the first type of luminescent layer 102 and the third type of luminescent layer 302 may have a microgap structure, or each of the first type of luminescent layer 102, the second type of luminescent layer 202, and the third type of luminescent layer 302 may have a microgap structure. Here, each of the microgap structures in the multi-color luminescent pixel units 1000 to 3000 shown in FIG1 to FIG3 may be, but is not limited to, an air gap. The air gap is sealed. Preferably, the cross-sectional dimension of the air gap is no greater than 2 nm, thereby releasing stress in the luminescent layer and preventing the luminescent layer from bending without affecting the luminous efficiency of the luminescent layer. 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.

[0044] FIG5 is a cross-sectional view illustrating a multi-color light-emitting pixel unit 5000 according to an embodiment of the present disclosure. As shown in FIG5 , each of the first type light-emitting layer 102, the second type light-emitting layer 202, and the third type light-emitting layer 302 can have multiple 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 light-emitting layer 102, the second type light-emitting layer 202, or the third type light-emitting layer 302. When multiple light-emitting layers are used in an 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 FIG5 , the micro-gap structures 06 are staggered across the multiple light-emitting layers. That is, the micro-gap structures 06 in the first-type light-emitting layer 102 are not vertically aligned with the micro-gap structures 06 in the second-type light-emitting layer 202, and the micro-gap structures 06 in the second-type light-emitting layer 202 are not vertically aligned with the micro-gap structures 06 in the third-type light-emitting layer 302. In each of the second-type LED 02 and the third-type LED 03, the micro-gap structures in the first-type light-emitting layer 102 are isolated and sealed between the second metal layer 201 at the top of the first-type light-emitting layer 102 and the first metal layer 101 at the bottom. In the third-type LED 03, the micro-gap structures 06 in the second-type light-emitting layer 202 are isolated and sealed between the third metal layer 301 at the top of the second light-emitting layer 202 and the second metal layer 201 at the bottom. Furthermore, the micro-gap structures 06 in the third-type light-emitting layer 302 are isolated and sealed between the top isolation layer 04 at the top of the third-type light-emitting layer 302 and the third metal layer 301 at the bottom.

[0046] In a similar manner, in another embodiment of the present disclosure, in a multi-color light-emitting pixel unit including first to M-th types of LEDs, the M-th type of LED has M light-emitting layers, and a metal layer is arranged at the bottom of each light-emitting layer, where M is a positive integer and is greater than or equal to two. In each of the first to M-th types of LEDs, a top conductive layer (as an upper conductive layer) is arranged on top of the top light-emitting layer, so that the microgap structure 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 microgap structure in each light-emitting layer is isolated and sealed between the metal layers at the top and bottom of the relative light-emitting layer, respectively.

[0047] In addition, similar to the multi-color light-emitting pixel units 1000 to 4000 in Figures 1 to 4, a multi-color light-emitting pixel unit according to another embodiment of the present disclosure includes multiple LEDs (including LEDs of the first type to LEDs of the Mth type). The Mth type LED includes at least all the light-emitting layers and metal layers constructed in the (M-1)th type LED, as well as the Mth light-emitting layer and the Mth metal layer. On this basis, the Mth type 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 (M-1)th type light-emitting layer, the (M-1)th metal layer... the first type light-emitting layer 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 Figure 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 between the first type LED and the Mth type 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 here. 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 types of LEDs. The top isolation layer of each type of LED has its opening, and the transparent conductive layer covers the surface of the top isolation layer and is filled in the opening, wherein 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 Figures 4 and 5, in a pixel unit having M types of LEDs, the sizes of the light-emitting areas of the first to Mth types of LEDs are different from each other. Depending on 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 size of the light-emitting area of ​​the 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 area of ​​the other types of LEDs. Alternatively, the other types of LEDs include at least a green LED or a blue LED.

[0048] A multi-color micro display panel according to an embodiment of the present disclosure is also provided. The micro display panel includes a plurality of multi-color pixel units arranged in a matrix. The multi-color pixel units herein may be the aforementioned 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] FIG6 is a flow chart illustrating a method for manufacturing the multi-color light-emitting pixel unit shown in FIG1 according to an embodiment of the present disclosure. FIG7 to FIG10 are cross-sectional views illustrating the structure formed in the steps illustrated in FIG6 according to an embodiment of the present disclosure. Referring to FIG6, the method for manufacturing the multi-color light-emitting pixel unit shown in FIG1 includes the following steps.

[0051] In step S601, referring to FIG7 , a stacked structure comprising a first metal layer 101, a first-type light-emitting layer 102, a second metal layer 201, and a second-type light-emitting layer 202 is formed from bottom to top on a substrate 100. In other words, the first-type light-emitting layer 102 and the second-type light-emitting layer 202 are stacked from bottom to top on the substrate 100. The first metal layer 101 is formed at the bottom of the first-type light-emitting layer 102. The second metal layer 201 is formed at the bottom of the second-type light-emitting layer 202. The second metal layer 201 is positioned between the first-type light-emitting layer 102 and the second light-emitting layer 202.

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

[0053] FIG11 is a flowchart illustrating details of step S601 in FIG6 according to an embodiment of the present disclosure. FIG12 to FIG21 are cross-sectional views illustrating the structure formed in the step illustrated in FIG11 according to an embodiment of the present disclosure. Referring to FIG11 , 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 a substrate 100 , a first type light emitting layer 102 is formed on a first base B1 , and a second metal bonding layer M02 is formed on top of the first type light emitting layer 102 .

[0055] More specifically, the first metal bonding layer M01 can be prepared by, but not limited to, physical vapor deposition (such as evaporation, sputtering, etc.). The material of the first substrate B1 is designed based on the first type of light-emitting layer 102. For example, the first substrate B1 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 B1. The second metal bonding layer M02 can be prepared by, but 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 turned upside 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 a first metal layer 101 .

[0057] In step S103 , referring to FIG. 14 in combination with FIG. 13 , the first substrate B1 is removed.

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

[0059] In addition, according to the 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, referring to Figure 16, step S103 may further include: forming a microgap structure 06 in the first type of light-emitting layer 102. The microgap structure 06 is formed by, but not limited to, photolithography and etching. In the photolithography method, the photolithographic pattern is designed according to the size of the microgap structure 06. According to the embodiment, the cross-sectional size of the microgap structure pattern is not greater than 2nm. Here, the cross-sectional size of the air gap can 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 , referring to FIG. 17 , a third metal bonding layer M03 is formed on the first type light emitting layer 102 , a second type light emitting layer 202 is formed on the second substrate B2 , and a fourth metal bonding layer M04 is formed on top of the second type light emitting layer 202 .

[0061] In step S105, referring to FIG. 17 and FIG. 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 a second metal layer 201.

[0062] In step S106 , referring to FIG. 19 in combination with FIG. 18 , the second substrate B2 is removed.

[0063] Here, after the second substrate B2 is removed, referring to FIG. 20 , in step S106 , the second type light emitting layer 202 is thinned.

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

[0065] Referring back to FIG. 6 to FIG. 10 , the process after step S601 according to an embodiment 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 portion of the top of the first type light emitting layer 102 is exposed, thereby forming a stepped structure made of the second type light emitting layer 202 on the first type light emitting layer 102 .

[0067] More specifically, the patterning of the second-type light-emitting layer 202 and the second metal layer 201 can be performed using photolithography and plasma etching. The patterning of the second-type light-emitting layer 202 and the second metal layer 201 also 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 are not limited herein.

[0068] In step S603, referring to FIG9 , 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 the predetermined first-type light-emitting area A01 and the predetermined second-type light-emitting area A02, thereby dividing the first-type light-emitting layer 102 in the first-type light-emitting area A01 from the first-type light-emitting layer 102 in the second-type light-emitting area A02, and dividing the first metal layer 101 in the first-type light-emitting area A01 from the first metal layer 101 in the second-type light-emitting area A02. As a result of step S603, a first-type LED 01 including a first segment 101-1 of the first metal layer and a first segment 102-1 of the first-type light-emitting layer is formed, and a second-type LED 02 including a second segment 101-2 of the first metal layer, a second segment 102-2 of the first-type light-emitting layer, a first segment 201-1 of the second metal layer, and a second segment 202-1 of the second-type light-emitting layer is formed.

[0069] Here, 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, the plurality of multi-color light-emitting pixel units are divided into groups according to a predetermined pixel unit array. In this way, the pixel units and / or the light-emitting transistors in the pixel unit array can be manufactured through a single division step, which simplifies the process and reduces production costs, particularly facilitating large-scale production.

[0071] In step S604 , referring to FIG10 , a shared top electrode layer 05 serving as an extraction electrode of the second metal layer 201 is formed on top of the first segment 102 - 1 of the first type light emitting layer and the first segment 202 - 1 of the second type light emitting layer in the second type light emitting area A02 .

[0072] FIG22 is a flowchart illustrating details of step S604 in FIG6 according to an embodiment of the present disclosure. FIG23 to FIG25 are cross-sectional views illustrating the structure formed in the steps illustrated in FIG22 according to an embodiment of the present disclosure. Referring to FIG22 , the specific process of step S604 includes the following steps.

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

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

[0075] 26 and 27 are cross-sectional views showing a structure 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, in combination with Figure 24, referring to Figure 26, a mask Y is formed to cover the area without the first electrical connector 203, thereby exposing the top and side walls of the first segment 201-1 of the second metal layer in the second type of light-emitting area A02, the side walls of the second segment 102-2 of the first type of light-emitting layer, and the side walls of the second segment 101-2 of the first metal layer.

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

[0078] In step S4023, referring again to Figure 10, mask Y and the conductive material 203' on mask Y are removed, thereby forming a first electrical connector 203 on the top and side walls of the first segment 201-1 of the second metal layer of the second type of light-emitting area A02, on the side walls of the second segment 102-2 of the first type of light-emitting layer, and on the side walls of the second segment 101-2 of the first metal layer.

[0079] The process of manufacturing the shared top electrode layer 05 will be further described below.

[0080] 25 , an isolation layer 04 is formed to cover the first-type light-emitting area A01, the second-type light-emitting area A02, and the exposed surface of the substrate 100. The isolation layer 04 has openings on the first segment 102-1 of the first-type light-emitting layer of the first-type light-emitting area A01 and the first segment 202-1 of the second-type light-emitting layer of the second-type light-emitting area A02.

[0081] 10 , after step S403, a continuous shared top electrode layer 05 is formed on the entire substrate 100 by, for example, deposition. The shared top electrode layer 05 formed in the opening is connected to the first segment 102-1 of the first type of light-emitting layer in the first type of light-emitting region A01 and the first segment 202-1 of the second type of light-emitting layer in the second type of light-emitting region A02.

[0082] FIG28 illustrates the structure of a multi-color light-emitting pixel unit according to an embodiment of the present disclosure, wherein the multi-color light-emitting pixel unit has a micro-gap structure in the first type light-emitting layer 102 and the second type light-emitting layer 202 .

[0083] FIG29 is a flow chart illustrating a method for manufacturing the multi-color light-emitting pixel unit 3000 shown in FIG3 according to an embodiment of the present disclosure. FIG30 to FIG34 are cross-sectional views illustrating the structure formed in the steps illustrated in FIG6 according to an embodiment of the present disclosure. Referring to FIG29 , the method for manufacturing the multi-color light-emitting pixel unit 3000 shown in FIG3 includes the following steps.

[0084] In step S701, referring to FIG30 , a stacked structure comprising a first metal layer 101, a first-type light-emitting layer 102, a second metal layer 201, a second-type light-emitting layer 202, a third metal layer 301, and a third-type light-emitting layer 302 is formed on a substrate 100 in order from bottom to top. In other words, the first-type light-emitting layer 102, the second-type light-emitting layer 202, and the third-type 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 light-emitting layer 102. The second metal layer 201 is formed at the bottom of the second-type light-emitting layer 202. The third metal layer 301 is formed at the bottom of the third-type light-emitting layer 302. The second metal layer 201 is positioned between the first-type light-emitting layer 102 and the second-type light-emitting layer 202. The third metal layer 301 is positioned between the second-type light-emitting layer 202 and the third-type light-emitting layer 302.

[0085] FIG35 is a flow chart illustrating details of step S701 in FIG29 according to an embodiment of the present disclosure. Referring to FIG35 in conjunction with FIG30 , 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 accompanying drawings. However, those skilled in the art can understand steps S801 to S809 of this embodiment by referring to steps S101 to S109 of the above-described embodiment.

[0086] In step S801 , a first metal bonding layer is formed on the substrate 100 , a first type light emitting layer 102 is formed on the first base, and a second metal bonding layer is formed on top of the first type 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 based on 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 turned upside down so that the second metal bonding layer faces the first metal bonding layer, and 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 light-emitting layer 102. In addition, after removing the first substrate or thinning the first type light-emitting layer 102, and before forming the third metal bonding layer, referring to FIG36, step S803 may further include: forming a microgap structure 06 in the first type light-emitting layer 102. The microgap structure 06 is formed by, but not limited to, photolithography and etching. In the photolithography method, the photolithographic pattern is designed according to the size of the microgap structure 06. According to the embodiment, the cross-sectional size of the microgap structure pattern is not greater than 2nm.

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

[0092] In step S805 , the second substrate is turned upside 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 light-emitting layer 202. Furthermore, after removing the second substrate or thinning the second type light-emitting layer 202, referring to FIG. 36 , step S106 further includes forming a microgap structure 06 in the second type light-emitting layer 202. Microgap structure 06 can be formed using a process similar to the process for forming microgap structure 06 described above. Therefore, the process for forming microgap structure 06 will not be repeated.

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

[0096] In step S808 , the third substrate is turned upside 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 light-emitting layer 302. Furthermore, after removing the third substrate or thinning the third type light-emitting layer 302, referring to FIG36 , step S109 further includes forming a microgap structure 06 in the third type light-emitting layer 302. Microgap structure 06 can be formed using a process similar to the process for forming microgap structure 06 described above. Therefore, the process for forming microgap structure 06 will not be repeated.

[0099] FIG36 shows the micro-gap structure 06 in the first type light-emitting layer 102 , the second type light-emitting layer 202 , and the third type light-emitting layer 302 .

[0100] Referring back to FIG. 30 to FIG. 34 , the process after step S701 will be further described below.

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

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

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

[0104] More specifically, the stepped structure is formed by the second-type light-emitting layer 202 and the second metal layer 201. The patterning process can be performed using photolithography and plasma etching. The patterning of the second-type light-emitting layer 202 and the second metal layer 201 also 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 are not limited here.

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

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

[0107] According to the embodiment, as a result of step S704, the plurality of multi-color light-emitting pixel units are divided into groups according to a predetermined pixel unit array. Therefore, the pixel units and / or the light-emitting transistors in the pixel unit array can be manufactured in a single division step, which simplifies the process and reduces production costs, particularly facilitating large-scale production.

[0108] In step S705, referring to Figure 34, a shared top electrode layer 05 serving as an extraction electrode for the first segment 201-1 of the second metal layer and an extraction electrode for the first segment 301-1 of the third metal layer is formed on top of the first segment 102-1 of the first type of light-emitting layer, the first segment 202-1 of the second type of light-emitting layer, and the first segment 302-1 of the third type of light-emitting layer.

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

[0110] 38 , a portion of the first segment 302-1 of the third type light emitting layer and a portion of the first segment 202-1 of the second type light emitting layer are removed, thereby exposing a portion of the first segment 201-1 of the second metal layer and a portion of the first segment 301-1 of the third metal layer.

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

[0112] More specifically, referring to Figure 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 figure, but those skilled in the art can understand steps S5021 to S5023 by referring to steps S4021 to S4023 of the above embodiment.

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

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

[0115] In step S5023, referring to Figure 39, the mask and the conductive material on the mask are removed, thereby forming a first electrical connector 203 on the top and side walls of the first segment 201-1 of the second metal layer in the second type of light-emitting area A02, on the side walls of the second segment 102-2 of the first type of light-emitting layer, and on the side walls of the second segment 101-2 of the first metal layer, and a second electrical connector 303 is formed on the top and side walls of the first segment 301-1 of the third metal layer in the third type of light-emitting area A03, on the side walls of the second segment 202-2 of the second type of light-emitting layer, on the side walls of the second segment 201-2 of the second metal layer, on the side walls of the third segment 102-3 of the first type of light-emitting layer, and on the side walls of the third segment 101-3 of the first metal layer.

[0116] The process of manufacturing the shared top electrode layer 05 will be further described below.

[0117] 40 , an isolation layer 04 is formed to cover the first type light emitting area A01, the second type light emitting area A02, the third type light emitting area A03, and the exposed surface of the substrate 100. The isolation layer 04 has openings on the first segment 102-1 of the first type light emitting layer, the first segment 202-1 of the second type light emitting layer, and the first segment 302-1 of the third type light emitting layer.

[0118] 34 , after step S503, a continuous shared top electrode layer 05 is formed on the entire substrate 100. The shared top electrode layer 05 deposited in the opening is connected to the first segment 102-1 of the first type of light-emitting layer, to the first segment 202-1 of the second type of light-emitting layer, and to the first segment 302 of the third type of light-emitting layer.

[0119] As mentioned above, in the method for manufacturing a multi-color luminous pixel unit according to an embodiment of the present disclosure, since the film deposition process of each type of LED can be performed simultaneously, the LEDs can be prepared simultaneously without having to be prepared separately, thereby simplifying the process of manufacturing the multi-color luminous pixel unit and the micro-LED display panel and promoting large-scale production. Due to the manufacturing method according to the embodiment of the present disclosure, different types of LEDs are arranged side by side on the same substrate with a short distance between each other. Therefore, the size of the LED and the display panel made of the LED can be reduced. For example, the size of each LED can be 40μm×40μm. 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, thereby exposing different types of light-emitting layers on the tops of different types of LEDs, thereby ensuring the light-emitting area and improving the luminous efficiency of each LED, and improving the integration of various LEDs. The micro-LED display panel formed by the pixel unit of the 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 Mth type LED, the Mth type light-emitting layer (which is the top light-emitting layer) in the Mth type LED can emit light, while the other light-emitting layers in the Mth type LED are short-circuited due to the electrical connection between the metal layers arranged on both sides of each other light-emitting layer. For example, in the Mth type LED, the first type of light-emitting layer is short-circuited due to the electrical connection between the first type of metal layer and the second type of metal layer arranged on both sides of the first type of light-emitting layer; the second type of light-emitting layer is short-circuited due to the electrical connection between the second type of metal layer and the third type of metal layer arranged on both sides of the second type of light-emitting layer; and so on. Therefore, the various types of LEDs emit light separately without affecting each other. In addition, the micro-gap in the light-emitting layer can release the stress inside the light-emitting layer and prevent it from warping without affecting the luminous efficiency of the light-emitting layer, thereby improving the product yield.

[0120] While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims.

Claims

1. A multi-color luminescent pixel unit, comprising: substrate; A light emitting transistor is formed on the substrate, the light emitting transistor comprising: a bottom conductive layer formed on the substrate and a top conductive layer formed over the bottom conductive layer; an upper light emitting layer formed between the top conductive layer and the bottom conductive layer; at least one lower light emitting layer formed between the upper light emitting layer and the bottom conductive layer; and an electrical connector electrically connecting the at least one lower light emitting layer and the bottom conductive layer; a top electrode layer covering the light emitting transistor; and forming an isolation layer between the top electrode layer and the light emitting transistor, wherein the isolation layer includes an opening on the light emitting transistor, and The top electrode layer contacts the light emitting transistor through the opening in the isolation layer.

2. The multi-color luminescent pixel unit according to claim 1, further comprising: A metal layer is formed between the upper light emitting layer and the at least one lower light emitting layer. 3 . The multi-color light-emitting pixel unit according to claim 2 , wherein the electrical connector is attached to and contacts side surfaces of the metal layer, the at least one lower light-emitting layer, and the bottom conductive layer. 4 . The multi-color light-emitting pixel unit according to claim 2 , wherein the electrical connector is attached to and contacts side surfaces of the metal layer and the bottom conductive layer. 5 . The multi-color light-emitting pixel unit according to claim 1 , wherein the electrical connector is attached to and contacts a side surface of the light-emitting transistor.

6. The multi-color light-emitting pixel unit according to claim 1 , wherein the at least one lower light-emitting layer comprises: a first lower light-emitting layer formed between the upper light-emitting layer and the bottom conductive layer; as well as A second lower light emitting layer is formed between the first lower light emitting layer and the bottom conductive layer. 7 . The multi-color light-emitting pixel unit according to claim 6 , wherein the electrical connector electrically connects the first lower light-emitting layer and the second lower light-emitting layer.

8. The multi-color luminescent pixel unit according to claim 6, further comprising: a first metal layer formed between the upper light-emitting layer and the first lower light-emitting layer; as well as A second metal layer is formed between the first lower light emitting layer and the second lower light emitting layer. 9 . The multi-color light-emitting pixel unit according to claim 8 , wherein the electrical connector is attached to and contacts side surfaces of the first metal layer, the second metal layer, the first lower light-emitting layer, the second lower light-emitting layer, and the bottom conductive layer. 10 . The multi-color light-emitting pixel unit according to claim 8 , wherein the electrical connector is attached to and contacts side surfaces of the first metal layer, the second metal layer, and the bottom conductive layer. 11 . The multi-color light-emitting pixel unit according to claim 1 , wherein the light-emitting transistor is a blue light-emitting transistor, and the upper light-emitting layer is a blue light-emitting layer. 12 . The multi-color light-emitting pixel unit according to claim 11 , wherein the at least one lower light-emitting layer comprises a red light-emitting layer and a green light-emitting layer. 13 . The multi-color light-emitting pixel unit according to claim 12 , wherein the electrical connector electrically connects both the red light-emitting layer and the green light-emitting layer to the bottom conductive layer. 14 . The multi-color light-emitting pixel unit according to claim 1 , wherein the light-emitting transistor is a green light-emitting transistor, and the upper light-emitting layer is a green light-emitting layer. 15 . The multi-color light-emitting pixel unit according to claim 14 , wherein the at least one lower light-emitting layer comprises a red light-emitting layer. 16 . The multi-color light-emitting pixel unit according to claim 15 , wherein the electrical connector electrically connects the red light-emitting layer to the bottom conductive layer.

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

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