Light-emitting structure, display panel and preparation method of display panel

Abstract

The invention discloses a light-emitting structure, a display panel and a preparation method of the display panel. The light-emitting structure comprises at least two light-emitting units which are vertically stacked, and the light-emitting colors of the at least two light-emitting units are different; the light-emitting unit comprises a light-emitting part and an electrode leading-out part on one side of the light-emitting part, the electrode leading-out part is provided with a first electrode and a second electrode, and the first electrode and the second electrode are arranged on the two opposite sides of the electrode leading-out part in the vertical stacking direction of the light-emitting unit; and the orthographic projection of the electrode lead-out part of any light-emitting unit and the orthographic projection of other light-emitting units in the vertical stacking direction of the light-emitting units are not overlapped. According to the technical scheme of the embodiment of the invention, the pixel aperture opening ratio of the light-emitting structure can be improved, and the photoetching process difficulty in the preparation process is reduced.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of display panels, and in particular to a light-emitting structure, a display panel, and a method for manufacturing the display panel. Background Art

[0002] With the development of display technology, augmented reality (AR) technology has emerged. The display of AR devices needs to have extremely high brightness and pixel density to achieve good virtual imaging effects. Therefore, Micro-LED displays have shown great application advantages in the field of AR devices due to their small size and high brightness.

[0003] In the prior art, full-color display is mainly achieved by combining light source devices with light conversion quantum dots, or by stacking light-emitting units in a horizontally distributed manner, or by stacking light-emitting units in a vertically distributed manner.

[0004] However, in all the above technologies, there are problems such as low utilization rate of the epitaxial structure of the light-emitting unit and small actual pixel aperture ratio, and the difficulty of the photolithography process in the preparation process of the light-emitting structure is relatively high. Summary of the invention

[0005] The present invention provides a light-emitting structure, a display panel and a method for preparing the display panel, so as to improve the pixel aperture ratio of the light-emitting structure and reduce the difficulty of the photolithography process during the preparation process.

[0006] According to one aspect of the present invention, there is provided a light emitting structure, comprising: at least two light emitting units stacked vertically, wherein the light emitting colors of at least two of the light emitting units are different;

[0007] The light-emitting unit comprises a light-emitting portion and an electrode lead-out portion on one side of the light-emitting portion, wherein the electrode lead-out portion is provided with a first electrode and a second electrode, and the first electrode and the second electrode are provided on opposite sides of the electrode lead-out portion in a direction along which the light-emitting unit is vertically stacked;

[0008] The electrode lead-out portion of any of the light-emitting units does not overlap with the orthographic projection of other light-emitting units in the direction in which the light-emitting units are vertically stacked.

[0009] Optionally, the first electrode is disposed on a first side of the electrode lead-out portion, and the second electrode is disposed on a second side of the electrode lead-out portion;

[0010] The first side of the electrode lead-out portion is a side close to the light emitting surface of the light emitting structure, and the second side of the electrode lead-out portion is a side away from the light emitting surface of the light emitting structure;

[0011] Preferably, the light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer which are stacked; the first electrode is electrically connected to the first semiconductor layer and is disposed on a side of the first semiconductor layer away from the second semiconductor layer; the second electrode is electrically connected to the second semiconductor layer and is disposed on a side of the second semiconductor layer away from the first semiconductor layer.

[0012] Optionally, the orthographic projections of the light-emitting parts of each of the light-emitting units in the direction in which the light-emitting units are vertically stacked at least partially overlap;

[0013] Optionally, the orthographic projections of the light-emitting parts of each light-emitting unit in the direction of vertical stacking of the light-emitting units completely overlap.

[0014] Optionally, the orthographic projections of the first electrode and the second electrode of the same light-emitting unit in the direction of vertical stacking of the light-emitting units at least partially overlap;

[0015] Optionally, the orthographic projections of the first electrode and the second electrode of the same light-emitting unit in the direction of vertical stacking of the light-emitting units completely overlap.

[0016] Optionally, the light emitting portion includes a central area and an edge area surrounding the central area; wherein the electrode lead-out portion is connected to the edge area.

[0017] Optionally, the edge region includes a plurality of sub-edge regions, and different sub-edge regions are located in different directions of the central region; each of the electrode lead-out portions is connected to the same sub-edge region of the corresponding light-emitting portion;

[0018] Alternatively, each of the electrode lead-out portions is connected to a different sub-edge region of the corresponding light-emitting portion;

[0019] Preferably, the light emitting portion partially surrounds the corresponding electrode lead-out portion;

[0020] Preferably, the electrode lead-out portion is located at a corner of the light-emitting unit, and different electrode lead-out portions are located at different corners of the light-emitting unit.

[0021] According to another aspect of the present invention, there is provided a display panel comprising a plurality of light emitting structures as described in any embodiment of the first aspect.

[0022] Preferably, an isolation structure is provided between adjacent light-emitting structures, and the isolation structure is opaque to light;

[0023] Preferably, the isolation structure comprises: an insulating layer and a light-blocking layer; the insulating layer is located between the light-emitting structure and the light-blocking layer, and the light-blocking layer is used to reduce optical crosstalk between adjacent light-emitting structures;

[0024] Preferably, the display panel further comprises: an array definition layer and a drive circuit layer;

[0025] The array definition layer is arranged on a side of the first electrode away from the second electrode, and the driving circuit layer is arranged on a side of the array definition layer away from the first electrode;

[0026] The first electrodes of the light-emitting units are respectively bonded to the array definition layer, and the array definition layer is electrically connected to the driving circuit layer; the second electrodes of the light-emitting units are connected to each other.

[0027] According to another aspect of the present invention, there is also provided a method for preparing a display panel, comprising:

[0028] Providing at least two vertically stacked light-emitting unit layers; the light-emitting colors of at least two of the light-emitting unit layers are different; the light-emitting unit layer comprises a plurality of light-emitting units, and the light-emitting unit comprises a light-emitting portion and an electrode lead-out portion on one side of the light-emitting portion;

[0029] Along the vertical stacking direction of the light-emitting unit layers, a first electrode and a second electrode are respectively formed on opposite sides of each of the electrode lead-out portions;

[0030] The electrode lead-out portion of the light-emitting unit in any light-emitting unit layer does not overlap with the orthographic projection of the light-emitting unit in other light-emitting unit layers in the direction in which the light-emitting unit layers are vertically stacked.

[0031] Optionally, providing at least two vertically stacked light emitting unit layers comprises:

[0032] Providing an epitaxial structure on one side of the substrate; the epitaxial structure comprises at least two light-emitting unit layers stacked vertically, the light-emitting unit layer comprises a first whole semiconductor layer, a whole light-emitting layer and a second whole semiconductor layer stacked, and the light-emitting colors of the whole light-emitting layers of the light-emitting unit layers are different;

[0033] Performing front-side patterning and back-side patterning on the epitaxial structure respectively, forming a first semiconductor layer, a light-emitting layer, and a second semiconductor layer of a plurality of light-emitting units, as well as light-emitting parts and electrode lead-out parts of the plurality of light-emitting units in each of the light-emitting unit layers;

[0034] and / or,

[0035] In the direction of vertical stacking of the light-emitting unit layer, the first electrode and the second electrode are respectively formed on opposite sides of each electrode lead-out portion, including:

[0036] After front-side patterning, a first electrode is formed on a side of the first semiconductor layer of the electrode lead-out portion away from the second semiconductor layer; after back-side patterning, a second electrode is formed on a side of the second semiconductor layer of the electrode lead-out portion away from the first semiconductor layer, thereby forming a plurality of light-emitting structures.

[0037] Optionally, the performing front-side patterning and back-side patterning on the epitaxial structure respectively comprises:

[0038] Patterning the epitaxial structure to form a plurality of pixel definition grooves, and forming a first semiconductor layer, a light emitting layer, and a second semiconductor layer of a plurality of light emitting units in each of the light emitting unit layers;

[0039] An isolation structure is formed in the pixel definition groove; wherein the isolation structure is disposed between adjacent light-emitting structures and is opaque to light;

[0040] Patterning the light-emitting unit layer on the first surface of the epitaxial structure to form a patterned structure corresponding to the light-emitting portion and the electrode lead-out portion on the first surface of the epitaxial structure;

[0041] The light-emitting unit layer is patterned on the second surface of the epitaxial structure to form a patterned structure corresponding to the light-emitting portion and the electrode lead-out portion on the second surface of the epitaxial structure, and a plurality of the light-emitting portions and the electrode lead-out portions are formed; wherein the first surface and the second surface are two opposite surfaces of the epitaxial structure;

[0042] Preferably, forming an isolation structure in the pixel definition groove comprises:

[0043] Depositing an insulating material on the first surface of the epitaxial structure and the inner wall of the pixel definition groove to form an insulating layer;

[0044] Depositing a light-blocking material on a side of the insulating layer away from the epitaxial structure to form a light-blocking layer;

[0045] The side of the epitaxial structure where the light-blocking layer is formed is planarized, and the insulating layer and the light-blocking layer in the pixel definition groove are retained to form the isolation structure.

[0046] The technical solution of the embodiment of the present invention vertically stacks at least two light-emitting units with different light-emitting colors to form a light-emitting structure, which can effectively improve the pixel density compared to the horizontal distribution of each light-emitting unit in the existing solution. Each light-emitting unit is provided with a light-emitting portion and an electrode lead-out portion on one side of the light-emitting portion, and the orthographic projections of each electrode lead-out portion along the direction of vertical stacking of each light-emitting unit do not overlap. The first electrode and the second electrode are respectively arranged on the two opposite surfaces of each electrode lead-out portion, which can reduce the area proportion of the electrode preparation area in the epitaxial structure of the light-emitting unit compared to arranging the first electrode and the second electrode on the same side of the light-emitting unit, thereby effectively improving the pixel aperture ratio and the utilization rate of the epitaxial structure of the light-emitting unit. And the first electrode and the second electrode are respectively arranged on the two opposite surfaces of each electrode lead-out portion, which is conducive to reducing the difficulty of the photolithography process compared to arranging the first electrode and the second electrode on the same side of the light-emitting unit.

[0047] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 is a schematic diagram of a top view of a light-emitting structure provided according to an embodiment of the present invention;

[0050] Figure 2 A light emitting structure provided according to an embodiment of the present invention is provided along Figure 1 Schematic diagram of the cross-sectional structure along the A-A' direction;

[0051] Figure 3 is a structural schematic diagram of a light-emitting structure provided according to an embodiment of the present invention;

[0052] Figure 4 It is a structural schematic diagram of a light-emitting structure provided according to the relevant technology;

[0053] Figure 5 is a schematic diagram of a top view structure of a light emitting unit provided according to an embodiment of the present invention;

[0054] Figure 6 is a schematic diagram of a top view structure of another light emitting unit provided according to an embodiment of the present invention;

[0055] Figure 7 is a schematic diagram of a top view structure of another light emitting unit provided according to an embodiment of the present invention;

[0056] Figure 8 is a schematic diagram of a top view structure of another light emitting unit provided according to an embodiment of the present invention;

[0057] Fig. 9 is a schematic diagram of a top view structure of another light emitting unit provided according to an embodiment of the present invention;

[0058] Fig.10 is a schematic diagram of a top view structure of another light emitting unit provided according to an embodiment of the present invention;

[0059] Fig.11 is a schematic diagram of a top view structure of another light emitting unit provided according to an embodiment of the present invention;

[0060] Fig.12 is a schematic diagram of a top view structure of another light emitting unit provided according to an embodiment of the present invention;

[0061] Fig.13 A light emitting structure provided according to an embodiment of the present invention is provided along Figure 1 Schematic diagram of the cross-sectional structure along the B-B' direction;

[0062] Fig.14 is a schematic cross-sectional structural diagram of a display panel provided according to an embodiment of the present invention;

[0063] Fig.15 is a schematic flow chart of a method for preparing a display panel provided according to an embodiment of the present invention;

[0064] Fig.16 It is a schematic diagram of a specific process for preparing a vertically stacked light-emitting unit;

[0065] Fig.17 is a schematic diagram of the provided epitaxial structure;

[0066] Fig.18 It is a schematic diagram of the first electrode formed after the front side is patterned, and the intermediate structure after the back side is patterned;

[0067] Fig.19 is a schematic diagram of an intermediate structure in which a second electrode is formed after the reverse side is patterned;

[0068] Fig. 20 is a schematic structural diagram corresponding to specific steps of step S1102 in a method for preparing a display panel provided according to an embodiment of the present invention;

[0069] Fig.21It is a structural schematic diagram corresponding to specific steps of step S012 in a method for preparing a display panel provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0070] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0071] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0072] As described in the background technology, in the prior art, a conventional blue light-emitting unit array arrangement combined with red and green light conversion quantum dots is usually used to achieve full-color display of the display panel. When preparing a display panel with a high pixel density requirement, it is close to the limit of the current equipment process capability, and there are problems such as light crosstalk between different color lights and low conversion efficiency of light conversion quantum dots. Later, the relevant technology proposed to arrange each light-emitting unit in a spatial horizontal distribution. Since the electrodes of the light-emitting unit must be designed around the light-emitting area, the light-emitting structure has low light extraction efficiency and low utilization rate of the epitaxial structure of the light-emitting unit. Based on this, the prior art proposed a solution to arrange each light-emitting unit in a spatial vertical distribution, which can effectively improve the pixel density compared to distributing each light-emitting unit horizontally. However, in the existing solution of vertically stacking light-emitting units in space, the setting of the N electrode and the P electrode reduces the actual light extraction area of ​​the light-emitting structure, resulting in a significant reduction in the actual pixel aperture ratio of the light-emitting structure, and the photolithography process in the preparation process is more difficult.

[0073] Based on the above technical problem, an embodiment of the present invention provides a light-emitting structure. Figure 1 is a schematic diagram of a top view of a light emitting structure provided by an embodiment of the present invention, Figure 2A light emitting structure provided by an embodiment of the present invention is Figure 1 Schematic diagram of the cross-sectional structure along the A-A' direction. Figure 3 1 is a schematic diagram of a light emitting structure provided by an embodiment of the present invention. Figures 1 to 3 The light-emitting structure includes: at least two light-emitting units 10 stacked vertically, and the light-emitting colors of the at least two light-emitting units 10 are different.

[0074] The light-emitting unit 10 includes a light-emitting portion 101 and an electrode lead-out portion 102 on one side of the light-emitting portion 101, the electrode lead-out portion 102 is provided with a first electrode 103 and a second electrode 104, the first electrode 103 and the second electrode 104 are arranged on opposite sides of the electrode lead-out portion 102 along the direction Y1 of vertical stacking of the light-emitting unit 10; the electrode lead-out portion 102 of any light-emitting unit 10 does not overlap with the orthographic projection of other light-emitting units 10 in the direction Y1 of vertical stacking of the light-emitting unit 10.

[0075] The at least two light-emitting units 10 included in the light-emitting structure have different light-emitting colors, so that the light-emitting structure can achieve full-color display. Figure 3 In this embodiment, the light emitting structure includes three light emitting units 10, namely a red light emitting unit 100, a green light emitting unit 110 and a blue light emitting unit 120. The light emitting units 10 are stacked vertically, which effectively improves the pixel density compared to the horizontal distribution of the light emitting units.

[0076] Optionally, the orthographic projections of the light emitting parts 101 of each light emitting unit 10 in the direction Y1 in which the light emitting units 10 are vertically stacked at least partially overlap. In some optional embodiments of the present invention, the orthographic projections of the light emitting parts 101 of each light emitting unit 10 in the direction Y1 in which the light emitting units 10 are vertically stacked completely overlap. Exemplarily, in the embodiments of the present invention, Figure 1 and Figure 3 The figure shows that the orthographic projections of the light emitting parts 101 of each light emitting unit 10 in the vertical stacking direction Y1 of the light emitting unit 10 completely overlap. Figure 3 The double arrows in the figure indicate the vertical stacking direction Y1 of each light emitting unit 10. Such arrangement can reduce the area ratio of each light emitting structure in the complete display panel, thereby effectively improving the pixel density of the display panel and improving the clarity.

[0077] Figure 4 is a schematic diagram of a light emitting structure provided by the related art. Take the light emitting structure including a red light emitting unit 100, a green light emitting unit 110 and a blue light emitting unit 120 arranged vertically stacked as an example. Figure 4As shown, in the direction of vertical stacking of the light-emitting units, the first electrode 103 and the second electrode 104 are both arranged on the same side of each light-emitting unit 10. Since the electrode preparation area occupies a large proportion of the area of ​​the epitaxial structure of each light-emitting unit 10, the area of ​​the actual light-emitting area is greatly reduced, thereby resulting in a reduction in the actual pixel aperture ratio; and since two electrode areas are prepared on the same surface of the light-emitting unit 10, the electrode preparation space provided for each electrode is small, making the photolithography process more difficult.

[0078] For the light-emitting structure in which the light-emitting units 10 are vertically stacked, the embodiment of the present invention redesigns the arrangement positions of the first electrode 103 and the second electrode 104 on each light-emitting unit 10 , and each light-emitting unit 10 is provided with a light-emitting portion 101 and an electrode lead-out portion 102 .

[0079] The first electrode 103 and the second electrode 104 of each light-emitting unit 10 are respectively arranged on the two opposite surfaces of each electrode lead-out portion 102, so that only one electrode of each light-emitting unit 10 is arranged on one side surface of the light-emitting structure, and the other electrode of each light-emitting unit 10 is arranged on the opposite side surface of the light-emitting structure, that is, only the preparation area of ​​the first electrode 103 of each light-emitting unit 10 is arranged on one side surface of the light-emitting structure, and the preparation area of ​​the second electrode 104 of each light-emitting unit 10 is arranged on the opposite side surface of the light-emitting structure. Exemplarily, the first electrode 103 can be an N electrode and the second electrode 104 can be a P electrode; or the first electrode 103 can also be a P electrode and the second electrode 104 can be an N electrode, which is not limited here. In addition, in the embodiment of the present invention, the first electrodes 103 of different light-emitting units 10 can be arranged on the same side or different sides of the corresponding electrode lead-out portion 102, and the second electrodes 103 of different light-emitting units 10 can be arranged on the same side or different sides of the corresponding electrode lead-out portion 102, which is not specifically limited in this embodiment. In this way, the first electrode 103 and the second electrode 104 are respectively arranged on the two opposite surfaces of the electrode lead-out portion 102 of each light-emitting unit 10. Compared with the prior art in which the first electrode 103 and the second electrode 104 are arranged on the same side of the light-emitting unit 10, a larger electrode preparation space can be provided for each electrode during the electrode preparation process, thereby reducing the difficulty of the photolithography process. In addition, the two electrodes are arranged on the two opposite surfaces of each light-emitting unit 10, which can effectively reduce the area ratio of the electrode preparation area in the epitaxial structure of the light-emitting unit, improve the epitaxial utilization rate of the epitaxial structure and the pixel aperture ratio, and thus help reduce power consumption.

[0080] The technical solution of the embodiment of the present invention vertically stacks at least two light-emitting units 10 with different light-emitting colors to form a light-emitting structure. Compared with the existing solution in which each light-emitting unit 10 is horizontally distributed, the pixel density can be effectively improved. Each light-emitting unit 10 is provided with a light-emitting portion 101 and an electrode lead-out portion 102 on one side of the light-emitting portion 101, and the orthographic projections of each electrode lead-out portion 102 along the direction Y1 of vertical stacking of each light-emitting unit 10 do not overlap. Exemplarily, the embodiment is described by taking the first electrode lead-out portion 1021 provided on the red light-emitting unit 100, the second electrode lead-out portion 1022 provided on the green light-emitting unit 110, and the third electrode lead-out portion 1023 provided on the blue light-emitting unit 120 as an example. See Figure 1 and Figure 3 The red light-emitting unit 100, the green light-emitting unit 110 and the blue light-emitting unit 120 are vertically stacked to form a light-emitting structure, the first electrode lead-out portion 1021, the second electrode lead-out portion 1022 and the third electrode lead-out portion 1023 are all arranged on one side of the light-emitting portion 101 in the corresponding light-emitting unit 10, and the electrode lead-out portions 102 of the three light-emitting units 10 are arranged in a stepped shape, that is, the electrode lead-out portions 102 are staggered in the direction Y1 of the vertical stacking of the light-emitting units 10.

[0081] Disposing the first electrode 103 and the second electrode 104 on two opposite surfaces of each electrode lead-out portion 102, respectively, can reduce the area proportion of the electrode preparation region in the epitaxial structure of the light-emitting unit, compared with disposing the first electrode 103 and the second electrode 104 on the same side of the light-emitting unit 10, thereby effectively improving the pixel aperture ratio and the utilization rate of the epitaxial structure of the light-emitting unit 10. And disposing one electrode on one side surface of each light-emitting unit 10 is conducive to reducing the difficulty of the photolithography process, compared with disposing the first electrode 103 and the second electrode 104 on the same side of the light-emitting unit.

[0082] Continue to see Figure 2 and Figure 3 On the basis of the above embodiments, optionally, the first electrode 103 is arranged on the first side of the electrode lead-out portion 102, and the second electrode 104 is arranged on the second side of the electrode lead-out portion 102; wherein the first side of the electrode lead-out portion 102 is the side close to the light emitting surface of the light emitting structure, and the second side of the electrode lead-out portion 102 is the side away from the light emitting surface of the light emitting structure.

[0083] Exemplarily, the light emitting surface of the light emitting structure is the upper surface of the uppermost light emitting unit 10 in the vertical stacking direction Y1 of the light emitting units 10 in the light emitting structure; or the lower surface of the lowermost light emitting unit 10. The first electrode 103 is disposed on the first side surface of the electrode lead-out portion 102 of each light emitting unit 10, and the second electrode 104 is disposed on the second side surface of the electrode lead-out portion 102 of each light emitting unit 10. The first electrode 103 of each light emitting unit 10 can be prepared simultaneously in one step, and the second electrode 104 of each light emitting unit 10 can be prepared simultaneously in one step, thereby simplifying the preparation process. The first side and the second side of the electrode lead-out portion 102 are two sides opposite to the light emitting surface, and the first electrode 103 and the second electrode 104 are respectively disposed on the two opposite side surfaces of the electrode lead-out portion 102 to improve the pixel aperture ratio of the light emitting structure and the utilization rate of the epitaxial structure of the light emitting unit 10.

[0084] Based on the above embodiments, continue to refer to Figure 2 Preferably, the light-emitting unit 10 includes a first semiconductor layer 11, a light-emitting layer 12, and a second semiconductor layer 13 which are stacked; the first electrode 103 is electrically connected to the first semiconductor layer 11, and is arranged on a side of the first semiconductor layer 11 away from the second semiconductor layer 12; the second electrode 104 is electrically connected to the second semiconductor layer 12, and is arranged on a side of the second semiconductor layer 12 away from the first semiconductor layer 11.

[0085] The light-emitting layer 12 is disposed between the first semiconductor layer 11 and the second semiconductor layer 13, and is used to emit light of corresponding colors. The first semiconductor layer 11 and the second semiconductor layer 13 are respectively used to connect the first electrode 103 and the second electrode 104 to receive corresponding electrical signals to form an electric field, and control the light-emitting layer 12 to emit light. Exemplarily, the materials used for the first semiconductor layer 11 and the second semiconductor layer 13 can be P-type gallium nitride and N-type gallium nitride, and are not specifically limited. P-type gallium nitride can be selected as the first semiconductor layer 11 and N-type gallium nitride can be selected as the second semiconductor layer 13 according to actual conditions, or N-type gallium nitride can be selected as the first semiconductor layer 11 and P-type gallium nitride can be selected as the second semiconductor layer 13.

[0086] Based on the above embodiments, continue to refer to Figure 1 and Figure 2, optionally, the orthographic projections of the first electrode 103 and the second electrode 104 of the same light-emitting unit 10 in the direction Y1 in which the light-emitting units 10 are vertically stacked at least partially overlap. In some optional embodiments of the present invention, the orthographic projections of the first electrode 103 and the second electrode 104 of the same light-emitting unit 10 in the direction Y1 in which the light-emitting units 10 are vertically stacked completely overlap. Since a certain process preparation space is required for preparing electrodes, the electrode lead-out portion 102 for carrying the first electrode 103 and the second electrode 104 has a certain area. In order to make the area of ​​the electrode lead-out portion 102 smaller, so that it occupies a smaller area ratio in the epitaxial structure of the light-emitting unit and increases the area of ​​the light-emitting portion 101, the first electrode 103 and the second electrode 104 arranged on the two opposite surfaces of the electrode lead-out portion 102 can be aligned in the vertical direction, even if the orthographic projections of the first electrode 103 and the second electrode 104 in the direction Y1 in which the light-emitting units 10 are vertically stacked completely overlap. With such a configuration, the area of ​​the electrode lead-out portion 102 only needs to meet the process preparation space for preparing one electrode, so that the area of ​​the electrode lead-out portion 102 is minimized on the basis of meeting the process requirements, further improving the pixel aperture ratio and the utilization rate of the epitaxial structure of the light-emitting unit 10, and reducing the power consumption of the light-emitting structure.

[0087] Based on the above embodiments, Figure 5 is a schematic diagram of a top view of a light emitting unit provided in an embodiment of the present invention, Figure 6 FIG. 1 is a schematic diagram of a top view of another light emitting unit provided by an embodiment of the present invention. Figure 5 and Figure 6 Optionally, the light emitting portion 101 includes a central region 1011 and an edge region 1012 surrounding the central region 1011; wherein the dotted frame region is the central region 1011, and the region outside the dotted frame is the edge region 1012. The electrode lead portion 102 is connected to the edge region 1012. For example, taking the red light emitting unit 100 as an example, Figure 5 The central region 1011 of the light emitting portion 101 of the red light emitting unit 100 and the edge region 1012 surrounding the central region 1011 are shown. The first electrode lead-out portion 1021 is disposed in contact with the edge region 1012 of the light emitting portion 101; for example, Figure 5 As shown, the first electrode lead-out portion 1021 can be arranged outside the edge region 1012, that is, the first electrode lead-out portion 1021 is arranged to protrude from the edge of the light-emitting portion 101; or Figure 6 As shown, the first electrode lead-out portion 1021 may not protrude from the edge region 1012. For example, the edge of the first electrode lead-out portion 1021 is flush with the edge of the edge region 1012. The dotted line frame area is the area where the first electrode lead-out portion 1021 is located.

[0088] Based on the above embodiments, continue to refer to Figure 5 , illustratively, the edge region 1012 includes a plurality of sub-edge regions, and different sub-edge regions are located in different directions of the central region 1011; each electrode lead-out portion 102 is connected to the same sub-edge region of the corresponding light-emitting portion 101. Still taking the red light-emitting unit 100 as an example, the edge region 1012 around the central region 1011 of the light-emitting portion 101 may include a plurality of sub-edge regions, such as Figure 5 In the top view of the structure shown in FIG. 1 , the edge region 1012 may include a first sub-edge region 10121 located above the central region 1011, a second sub-edge region 10122 located below the central region 1011, a third sub-edge region 10123 located on the left side of the central region 1011, and a fourth sub-edge region 10124 located on the right side of the central region 1011. The electrode lead-out portion 102 may be disposed in contact with any sub-edge region of the central region 1011 of each light-emitting unit 10 surrounding the light-emitting portion 101. For example, for a light-emitting structure formed by vertically stacking a plurality of light-emitting units 10, see Figure 5 , the electrode lead-out portion 102 of each light-emitting unit 10 can be arranged in contact with the same sub-edge region of the central region 1011 of the corresponding light-emitting portion 101, for example, can be arranged in contact with the second sub-edge region 10122, and the electrode lead-out portion 102 is arranged protruding from the central region 1011. In other words, the electrode lead-out portions 102 are arranged in a stepped manner on the side of the same sub-edge region away from the central region 1011, that is, the electrode lead-out portions 102 are arranged in a staggered manner in the vertical direction, so that the first electrode 103 and the second electrode 104 can be respectively arranged on the two opposite surfaces of each electrode lead-out portion 102, so as to improve the pixel aperture ratio, which is conducive to reducing power consumption.

[0089] For example, Figure 7 is a schematic diagram of a top view of another light emitting unit provided in an embodiment of the present invention. Figure 8 is a schematic diagram of a top view of another light emitting unit provided in an embodiment of the present invention. Fig. 9 FIG. 1 is a top view of another light emitting unit provided in an embodiment of the present invention. Figures 7 to 9 The edge region 1012 includes a plurality of sub-edge regions, and different sub-edge regions are located in different directions of the central region 1011 ; each electrode lead-out portion 102 is connected to a different sub-edge region of the corresponding light-emitting portion 101 .

[0090] Optionally, the light emitting portion 101 partially surrounds the corresponding electrode lead-out portion 102 .

[0091] Here, the present embodiment is described by taking as an example that the red light emitting unit 100 is provided with the first electrode lead portion 1021 , the green light emitting unit 110 is provided with the second electrode lead portion 1022 , and the blue light emitting unit 120 is provided with the third electrode lead portion 1023 . Figures 7 to 9 The top view structures of the red light emitting unit 100, the green light emitting unit 110 and the blue light emitting unit 120 are shown respectively. The area contained in the dotted line frame is the electrode lead-out portion 102 corresponding to each light emitting unit 10, and the sub-edge area distribution of each light emitting unit 10 is the same as the example in the above embodiment, which will not be repeated here. Figure 7 It can be seen that the first electrode lead-out portion 1021 of the red light-emitting unit 100 is connected to the third sub-edge region 10123 of the light-emitting portion 101; Figure 8 It can be seen that the second electrode lead-out portion 1022 of the green light-emitting unit 110 is connected to the fourth sub-edge region 10124 of the light-emitting portion 101; Fig. 9 It can be seen that the third electrode lead-out portion 1023 of the blue light-emitting unit 120 is disposed in contact with the second sub-edge region 10122 of the light-emitting unit 101, that is, each light-emitting unit 101 surrounds the portion of the corresponding electrode lead-out portion 102 that is not in contact with the sub-edge region. In addition, the notch provided in the corresponding sub-edge region of the light-emitting unit 10 of each light-emitting unit 10 is used to completely expose the two opposite surfaces of the electrode lead-out portion 102 of each light-emitting unit 10 after the light-emitting units 10 are vertically stacked, so as to respectively provide the first electrode 103 and the second electrode 104 on the two surfaces.

[0092] Fig.10 is a schematic diagram of a top view of another light emitting unit provided in an embodiment of the present invention. Fig.11 is a schematic diagram of a top view of another light emitting unit provided in an embodiment of the present invention. Fig.12 FIG. 1 is a schematic diagram of a top view of another light emitting unit provided in an embodiment of the present invention. Figures 10 to 12 Optionally, the electrode lead-out portion 102 is located at a corner of the light-emitting unit 10 , and different electrode lead-out portions 102 are located at different corners of the light-emitting unit 10 .

[0093] The corner of the light-emitting unit 10 is the angle formed by the adjacent sub-edge regions at the intersection, Figures 10 to 12 It can be seen that the area included in the dotted frame is the corresponding electrode lead-out portion 102 of each light-emitting unit 10 . Figures 10 to 12 They are top view structural diagrams of the red light emitting unit 100, the green light emitting unit 110 and the blue light emitting unit 120. Fig.10 It can be seen that the first electrode lead-out portion 1021 of the red light-emitting unit 100 is disposed at the upper left corner formed by the first sub-edge region 10121 and the third sub-edge region 10123; Fig.11 It can be seen that the second electrode lead-out portion 1022 of the green light emitting unit 110 is disposed at the lower right corner formed by the second sub-edge region 10122 and the fourth sub-edge region 10124; Fig.12It can be seen that the third electrode lead-out portion 1023 of the blue light-emitting unit 120 is arranged at the lower left corner formed by the second sub-edge region 10122 and the third sub-edge region 10123, and each electrode lead-out portion 102 is a triangle. By arranging each electrode lead-out portion 102 at a different corner of the light-emitting unit 10, the area of ​​the electrode lead-out portion 102 in the epitaxial structure of the light-emitting unit 10 can be minimized, thereby further improving the pixel aperture ratio and the utilization rate of the epitaxial structure of the light-emitting unit 10, which is conducive to reducing power consumption.

[0094] Optionally, Fig.13 The embodiment of the present invention provides a light emitting structure along Figure 1 A schematic diagram of the cross-sectional structure along the BB' direction. Fig.13 As shown, a distributed Bragg reflector 14 is disposed between adjacent light emitting units 10 , and the distributed Bragg reflector 14 is used to reduce optical crosstalk generated between adjacent light emitting units 10 in a vertical stacking direction.

[0095] The distributed Bragg reflector 14 is also called a distributed Bragg reflector (DBR), which is a periodic structure composed of two materials with different refractive indices alternately stacked, and the optical thickness of each layer of material is one quarter of a wavelength. Fig.13 , one side surface of the light emitting structure is used as the light emitting surface 15, and in order to clearly indicate the position of the distributed Bragg reflection layer 14, Fig.13 The specific film layers included in each light emitting unit 10 are not shown. A distributed Bragg reflector 14 is arranged between two adjacent light emitting units 10 stacked vertically, so that the light emitted by the light emitting unit 10 can pass through the distributed Bragg reflector 14 close to the light emitting surface 15 and be emitted from the light emitting surface 15, but cannot pass through the distributed Bragg reflector 14 far from the light emitting surface 15, thereby reducing the optical crosstalk generated between adjacent light emitting units 10 in the vertical direction.

[0096] In addition, the material used to prepare the distributed Bragg reflector 14 may include semiconductor materials and insulating materials. For example, in this embodiment, the distributed Bragg reflector 14 is prepared using insulating materials to achieve insulation between the vertically stacked adjacent light-emitting units 10 in the vertical direction. For example, the insulating material may be silicon dioxide or titanium dioxide.

[0097] An embodiment of the present invention further provides a display panel. Fig.14 FIG. 1 is a schematic cross-sectional view of a display panel provided by an embodiment of the present invention. Fig.14As shown, the display panel includes a plurality of light-emitting structures 01 as described in any of the above embodiments. The display panel is provided with a plurality of light-emitting structures 01 arranged in an array, wherein the light-emitting structure 01 includes at least two light-emitting units with different light-emitting colors, and the light-emitting units are arranged in a vertical stacking manner, which effectively improves the pixel density of the display panel. An electrode lead-out portion 102 is provided on each light-emitting unit, and the electrode lead-out portion 102 of each light-emitting unit does not overlap with the orthographic projection of other light-emitting units in the direction Y1 of vertical stacking of the light-emitting unit 10. A first electrode 103 and a second electrode 104 are provided on the two opposite surfaces of each electrode lead-out portion 102, respectively. Compared with providing both electrodes on the same side of the light-emitting structure, the area proportion of the electrode preparation region in the epitaxial structure of the light-emitting unit is reduced, thereby improving the pixel aperture ratio of the light-emitting structure 01 and the utilization rate of the epitaxial structure, so that the luminous efficiency of the display panel is improved to a certain extent, which is conducive to reducing power consumption and reducing the difficulty of the photolithography process when preparing the electrode.

[0098] Based on the above embodiments, continue to refer to Fig.14 Optionally, an isolation structure 02 is provided between adjacent light-emitting structures 01 , and the isolation structure 02 is opaque.

[0099] The isolation structure 02 includes: an insulating layer 021 and a light-blocking layer 022 ; the insulating layer 021 is located between the light-emitting structure 01 and the light-blocking layer 022 , and the light-blocking layer 022 is used to reduce optical crosstalk between adjacent light-emitting structures 01 .

[0100] Among them, the light-blocking layer 022 in the isolation structure 02 is filled between two adjacent light-emitting structures 01, and an insulating layer 021 is provided between the light-blocking layer 022 and the light-emitting structure 01. Exemplarily, the insulating layer 021 can be made of silicon oxide material; since the insulating layer 021 may be a transparent film layer, the light-blocking layer 022 is provided between the insulating layers 021 to reduce the light crosstalk between adjacent light-emitting structures 01 and ensure that the display panel has a good display effect. Exemplarily, the light-blocking layer 022 can be prepared by selecting an opaque metal copper material, and the insulating layer 021 is used to insulate the light-emitting structure 01 from the light-blocking layer 022.

[0101] Optionally, the display panel further includes: an array definition layer 03 and a drive circuit layer 04 ; the array definition layer 03 is disposed on a side of the first electrode 103 away from the second electrode 104 , and the drive circuit layer 04 is disposed on a side of the array definition layer 03 away from the first electrode 103 .

[0102] The first electrodes 103 of each light-emitting unit 01 are bonded to the array definition layer 03 , respectively. The array definition layer 03 is electrically connected to the driving circuit layer 04 . The second electrodes 104 of each light-emitting unit 01 are connected to each other.

[0103] The first electrodes 103 of each light-emitting unit 01 are insulated from each other, so that the driving circuit layer 04 can provide corresponding level signals to the first electrodes 103 of each light-emitting unit 01, and form different electric fields with the common level signals of the second electrodes 104, thereby realizing individual lighting control of each light-emitting unit 01. The array definition layer 03 serves as a transition connection structure between the first electrodes 103 of each light-emitting unit 01 and the driving circuit layer 04. The first electrodes 103 are bonded to the array definition layer 03. The circuits provided in the array definition layer 03 are used to connect the first electrodes 103 of each light-emitting unit 01 to the driving circuits at corresponding positions on the driving circuit layer 04.

[0104] An embodiment of the present invention also provides a method for preparing a display panel. Fig.15 is a schematic diagram of a method for manufacturing a display panel provided by an embodiment of the present invention. Fig.15 , the method for preparing the display panel comprises:

[0105] S110, providing at least two vertically stacked light-emitting unit layers; the light-emitting colors of the at least two light-emitting unit layers are different; the light-emitting unit layer comprises a plurality of light-emitting units, and the light-emitting unit comprises a light-emitting portion and an electrode lead-out portion on one side of the light-emitting portion.

[0106] Exemplarily, three vertically stacked light-emitting unit layers may be included, including a red light-emitting unit layer, a green light-emitting unit layer, and a blue light-emitting unit layer. The red light-emitting unit layer includes a plurality of red light-emitting units, the green light-emitting unit layer includes a plurality of green light-emitting units, and the blue light-emitting unit layer includes a plurality of blue light-emitting units. Each light-emitting unit is provided with an electrode lead-out portion connected to the light-emitting portion, for example: the red light-emitting unit is provided with a first electrode lead-out portion, the green light-emitting unit is provided with a second electrode lead-out portion, and the blue light-emitting unit is provided with a third electrode lead-out portion.

[0107] S120. Along the direction of vertical stacking of the light-emitting unit layers, the first electrode and the second electrode are respectively formed on opposite sides of each electrode lead-out portion; the electrode lead-out portion of the light-emitting unit in any light-emitting unit layer does not overlap with the orthographic projection of the light-emitting unit in other light-emitting unit layers in the direction of vertical stacking of the light-emitting unit layers.

[0108] Exemplarily, the first electrode and the second electrode are respectively formed on the opposite side surfaces of each electrode lead-out portion. Compared with setting the first electrode and the second electrode on the same side surface of each light-emitting unit, the area occupied by the electrode preparation area in the light-emitting unit can be effectively reduced, thereby improving the pixel aperture ratio and reducing the difficulty of the photolithography process, thereby reducing power consumption.

[0109] The method for preparing a display panel provided by an embodiment of the present invention effectively improves the pixel density of the display panel by providing at least two light-emitting unit layers with different light-emitting colors and vertically stacking each light-emitting unit layer. Each light-emitting unit layer includes a plurality of light-emitting units, each light-emitting unit is provided with a light-emitting portion and an electrode lead-out portion connected to the light-emitting portion, and the electrode lead-out portion of the light-emitting unit in any light-emitting unit layer does not overlap with the positive projection of the light-emitting unit in the other light-emitting unit layer in the direction of vertical stacking of the light-emitting unit layer. The first electrode and the second electrode are respectively arranged on the two opposite side surfaces of each electrode lead-out portion. Compared with arranging the first electrode and the second electrode on the same side surface of each light-emitting unit, the area ratio occupied by the electrode preparation area on the surface of the light-emitting unit can be effectively reduced, thereby effectively improving the pixel aperture ratio and reducing the difficulty of the photolithography process.

[0110] Fig.16 This is a schematic diagram of the specific process of preparing vertically stacked light-emitting units. Fig.17 is a schematic diagram of the epitaxial structure provided. Fig.16 and Fig.17 , providing at least two light emitting units stacked vertically, comprising:

[0111] S1101. Provide an epitaxial structure 00 on one side of a substrate 03; the epitaxial structure 00 includes at least two light-emitting unit layers 10 stacked vertically, the light-emitting unit layer 10 includes a first entire semiconductor layer 11, an entire light-emitting layer 12 and a second entire semiconductor layer 13 stacked in layers, and the entire light-emitting layer 12 of each light-emitting unit layer 10 has a different light-emitting color.

[0112] For example, see Fig.17 , Fig.17 The epitaxial structure on one side of the substrate 03 is shown. The epitaxial structure may include three vertically stacked light-emitting unit layers, namely a red light-emitting unit layer, a green light-emitting unit layer, and a blue light-emitting unit layer. The entire light-emitting layer in each light-emitting unit layer emits different light colors. For example, the entire light-emitting layer in the red light-emitting unit layer emits red light, the entire light-emitting layer in the green light-emitting unit layer emits green light, and the entire light-emitting layer in the blue light-emitting unit layer emits blue light, so that the prepared display panel can achieve full-color display.

[0113] S1102 , patterning the epitaxial structure 00 on the front and back respectively, forming a first semiconductor layer 11 , a light-emitting layer 12 , and a second semiconductor layer 13 of a plurality of light-emitting units, as well as light-emitting portions and electrode lead-out portions 102 of a plurality of light-emitting units in each light-emitting unit layer 10 .

[0114] Among them, by patterning the corresponding light-emitting unit layer on the front and back sides of the epitaxial structure, a corresponding light-emitting portion and an electrode lead-out portion are formed on each light-emitting unit, and a protective layer 05 is coated on the front and back sides of the light-emitting portion and the electrode lead-out portion. For example, the protective layer 05 can be prepared by using a transparent colloid or a material such as silicon oxide, silicon nitride, etc., so as to fill and level the epitaxial structure and facilitate subsequent operations.

[0115] Fig.18 It is a schematic diagram of the first electrode formed after the front side is patterned, and the intermediate structure after the back side is patterned. Fig.19 Schematic diagram of the intermediate structure of the second electrode formed after the reverse side is patterned. Fig.18 and Fig.19 Optionally, in the direction of vertical stacking of the light-emitting units, a first electrode and a second electrode are formed on opposite sides of each electrode lead-out portion, respectively, including:

[0116] S1201. After front-side patterning, a first electrode 103 is formed on a side of the first semiconductor layer 11 of the electrode lead-out portion 102 away from the second semiconductor layer 13. After back-side patterning, a second electrode 104 is formed on a side of the second semiconductor layer 13 of the electrode lead-out portion 102 away from the first semiconductor layer 11, thereby forming a plurality of light-emitting structures 01.

[0117] For example, see Fig.18 and Fig.19 , Fig.18 The structure of setting the first electrode at the position corresponding to the electrode lead-out portion on the front side of the epitaxial structure after the front side of the epitaxial structure is patterned is shown. Fig.19 The structure of setting a second electrode at the position of the electrode lead-out portion corresponding to the reverse side of the epitaxial structure after the reverse side of the epitaxial structure is patterned is shown. The first electrode and the second electrode are respectively formed on the two opposite surfaces of the electrode lead-out portion, so that only one electrode of each light-emitting unit is set on one side surface of the light-emitting structure, and another electrode is set on the other side surface opposite to the light-emitting structure, which can effectively reduce the area proportion of the electrode preparation area in the epitaxial structure of the light-emitting structure, thereby facilitating the improvement of the pixel aperture ratio and the utilization rate of the epitaxial structure. In addition, the electrode preparation area corresponding to one electrode of each light-emitting unit is formed by a patterning process on one side surface of the light-emitting unit; and the electrode preparation area corresponding to another electrode is formed by a patterning process on the other side surface opposite to the light-emitting unit, which can effectively reduce the difficulty of the photolithography process.

[0118] It should be noted that in the above embodiments, step S1102 and step S1201 can be performed alternately. Specifically, after the front side of the epitaxial structure 00 is patterned, a protective layer is formed on the front side, and a first electrode is formed at a position corresponding to the electrode lead-out portion; after the back side of the epitaxial structure is patterned, a protective layer is formed on the back side, and a second electrode is formed at a position corresponding to the electrode lead-out portion.

[0119] Continue to see Fig.18 and Fig.19 Optionally, after filling the protective layer 05 on one side of the electrode lead-out portion 102 and forming the first electrode 103, the method further includes:

[0120] An array definition layer 06 and a drive circuit layer 07 are formed on the surface of the protective layer 05 away from the electrode lead-out portion, and the front and back sides of the epitaxial structure 00 are turned over, and the substrate 03 on the back side is removed to facilitate back-side patterning of the epitaxial structure 00. The array definition layer 06 is bonded to each first electrode to achieve electrical connection between each first electrode and the drive circuit layer 07, so that the drive circuit layer 07 can provide corresponding level signals to each first electrode to achieve individual control of light emission of each light-emitting unit.

[0121] The display panel manufacturing method provided by the embodiment of the present invention provides an epitaxial structure formed by vertically stacking at least two light-emitting unit layers with different light-emitting colors on one side of the substrate, and performs front and back patterning on the epitaxial structure to form a plurality of light-emitting units and a light-emitting portion and an electrode lead-out portion of each light-emitting unit. In this way, by providing an electrode lead-out portion for each light-emitting unit, a first electrode and a second electrode can be respectively provided on two opposite surfaces of the electrode lead-out portion. Compared with providing both the first electrode and the second electrode on the same side surface of the light-emitting unit, the area ratio of the electrode preparation area in the epitaxial structure of the light-emitting unit is reduced, thereby effectively improving the pixel aperture ratio and the utilization rate of the epitaxial structure, and helping to reduce the difficulty of the photolithography process.

[0122] Fig. 20 FIG. 1 is a schematic diagram of the structure corresponding to the specific steps of step S1102 in a method for preparing a display panel provided in an embodiment of the present invention. Fig. 20 As shown, optionally, the epitaxial structure is patterned on the front side and the back side respectively, including:

[0123] S011 , patterning the epitaxial structure 00 to form a plurality of pixel definition grooves 04 , and forming a first semiconductor layer 11 , a light emitting layer 12 , and a second semiconductor layer 13 of a plurality of light emitting units 10 in each light emitting unit layer.

[0124] The pixel definition grooves formed by patterning are used to divide the entire epitaxial structure into a plurality of light-emitting units, namely, a plurality of pixels.

[0125] S012 , forming an isolation structure 02 in the pixel definition groove 04 ; wherein the isolation structure 02 is disposed between adjacent light-emitting structures 01 , and the isolation structure 02 is light-proof.

[0126] For example, the isolation structure formed in the pixel definition groove can insulate adjacent light-emitting unit layers arranged in the horizontal direction, and the isolation structure can be made of an opaque material, thereby effectively reducing the optical crosstalk generated between adjacent light-emitting unit layers arranged in the horizontal direction.

[0127] S013 , patterning the light-emitting unit layer on the first surface of the epitaxial structure 00 to form a patterned structure corresponding to the light-emitting portion 101 and the electrode lead-out portion 102 on the first surface of the epitaxial structure 00 .

[0128] Exemplarily, the epitaxial structure still includes a vertically stacked red light-emitting unit layer, a green light-emitting unit layer, and a blue light-emitting unit layer, and the red light-emitting unit layer is close to the first surface of the epitaxial structure. On the first surface of the epitaxial structure, the red light-emitting unit layer and the green light-emitting unit layer are patterned in turn by exposure, development and other processes, so as to form a patterned structure of the light-emitting part and the electrode lead-out part of each light-emitting unit layer on the first surface. After forming the patterned structure of the light-emitting part and the electrode lead-out part corresponding to the first surface of the epitaxial structure, a protective layer material is applied on the first surface to fill the first surface of the epitaxial structure. Thereafter, holes are punched at the positions of the patterned structures of each electrode lead-out part corresponding to the first surface, and electrode materials are deposited in the holes to form the first electrode.

[0129] S014. Patterning the light-emitting unit layer on the second surface of the epitaxial structure 00 to form a patterned structure corresponding to the light-emitting portion 101 and the electrode lead-out portion 102 on the second surface of the epitaxial structure 00, forming a plurality of light-emitting portions 101 and electrode lead-out portions 102; wherein the first surface and the second surface are two opposite surfaces of the epitaxial structure.

[0130] Exemplarily, the vertically stacked epitaxial structure provided by the above steps is still taken as an example, wherein the blue light-emitting unit layer is close to the second surface, and the second surface is a side surface of the epitaxial structure away from the first surface. On the second surface of the epitaxial structure, the blue light-emitting unit layer and the green light-emitting unit layer are patterned in turn by exposure, development and other processes, thereby forming the light-emitting portion and the electrode lead-out portion of each light-emitting unit layer. Afterwards, a colloid or protective layer material is coated on the second surface of the epitaxial structure, and holes are punched at the positions of each electrode lead-out portion corresponding to the second surface, and an electrode material is deposited on the second surface, thereby forming a second electrode in the hole, and the second electrode of each light-emitting unit layer is connected to the electrode layer deposited on the second surface, so that the second electrode becomes a common electrode.

[0131] By patterning the first and second surfaces opposite to each other of the epitaxial structure respectively, electrode lead-out portions whose orthographic projections do not overlap on the substrate are prepared. This effectively reduces the difficulty of the photolithography process compared to forming two electrode preparation areas for each light-emitting unit layer by patterning one surface of the epitaxial structure.

[0132] Fig.21 FIG. 1 is a schematic diagram of a structure corresponding to specific steps of step S012 in a method for preparing a display panel provided in an embodiment of the present invention. Fig.21 As shown, optionally, an isolation structure is formed in the pixel definition groove, including:

[0133] S0121 , depositing an insulating material on the first surface of the epitaxial structure 00 and the inner wall of the pixel definition groove 04 to form an insulating layer 021 .

[0134] By way of example, the insulating material may be a silicon oxide material. By using a deposition process, an insulating layer is formed on the first surface of the epitaxial structure and the inner wall of the pixel definition groove.

[0135] S0122 , depositing a light-blocking material on a side of the insulating layer 021 away from the epitaxial structure 00 to form a light-blocking layer 022 .

[0136] For example, the light-blocking material may be copper metal. A deposition process is used to deposit a light-blocking layer on the surface of the formed insulating layer, and the pixel definition grooves are filled with the light-blocking material.

[0137] S0123 , planarizing the side of the epitaxial structure on which the light-blocking layer 022 is formed, retaining the insulating layer 021 and the light-blocking layer 022 in the pixel definition groove, and forming an isolation structure 02 .

[0138] Illustratively, a chemical mechanical polishing (CMP) process is used to planarize one side of the first surface of the epitaxial structure to expose the first surface of the epitaxial structure, and an isolation structure whose surface is flush with the first surface of the epitaxial structure is formed in the pixel definition groove, thereby insulating two adjacent light-emitting structures and reducing optical crosstalk between the light-emitting structures.

[0139] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A light emitting structure, characterized in that: include: At least two light-emitting units stacked vertically, at least two of the light-emitting units emitting light of different colors; The light-emitting unit comprises a light-emitting portion and an electrode lead-out portion on one side of the light-emitting portion, wherein the electrode lead-out portion is provided with a first electrode and a second electrode, and the first electrode and the second electrode are provided on opposite sides of the electrode lead-out portion in a direction along which the light-emitting unit is vertically stacked; The electrode lead-out portion of any of the light-emitting units does not overlap with the orthographic projection of other light-emitting units in the direction in which the light-emitting units are vertically stacked.

2. The light emitting structure according to claim 1, characterized in that: The first electrode is disposed on a first side of the electrode lead-out portion, and the second electrode is disposed on a second side of the electrode lead-out portion; The first side of the electrode lead-out portion is a side close to the light emitting surface of the light emitting structure, and the second side of the electrode lead-out portion is a side away from the light emitting surface of the light emitting structure; Preferably, the light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer that are stacked; the first electrode is electrically connected to the first semiconductor layer and is disposed on a side of the first semiconductor layer away from the second semiconductor layer; the second electrode is electrically connected to the second semiconductor layer and is disposed on a side of the second semiconductor layer away from the first semiconductor layer.

3. The light emitting structure according to claim 1, characterized in that: The orthographic projections of the light-emitting parts of the light-emitting units in the direction in which the light-emitting units are vertically stacked at least partially overlap; Preferably, the orthographic projections of the light-emitting parts of each of the light-emitting units in the direction in which the light-emitting units are vertically stacked completely overlap.

4. The light emitting structure according to claim 1, characterized in that: The orthographic projections of the first electrode and the second electrode of the same light-emitting unit in the direction in which the light-emitting units are vertically stacked at least partially overlap; Preferably, the orthographic projections of the first electrode and the second electrode of the same light-emitting unit in the direction of vertical stacking of the light-emitting units completely overlap.

5. The light emitting structure according to claim 4, characterized in that: The light emitting portion includes a central area and an edge area surrounding the central area; wherein the electrode lead-out portion is connected to the edge area.

6. The light emitting structure according to claim 5, characterized in that: The edge region includes a plurality of sub-edge regions, and different sub-edge regions are located in different directions of the central region; each electrode lead-out portion is connected to the same sub-edge region of the corresponding light-emitting portion; Alternatively, each of the electrode lead-out portions is connected to a different sub-edge region of the corresponding light-emitting portion; Preferably, the light emitting portion partially surrounds the corresponding electrode lead-out portion; Preferably, the electrode lead-out portion is located at a corner of the light-emitting unit, and different electrode lead-out portions are located at different corners of the light-emitting unit.

7. A display panel, characterized in that: A light-emitting structure comprising a plurality of light-emitting structures according to any one of claims 1 to 6; Preferably, an isolation structure is provided between adjacent light-emitting structures, and the isolation structure is opaque to light; Preferably, the isolation structure comprises: an insulating layer and a light-blocking layer; the insulating layer is located between the light-emitting structure and the light-blocking layer, and the light-blocking layer is used to reduce light crosstalk between adjacent light-emitting structures; Preferably, the display panel further comprises: an array definition layer and a drive circuit layer; The array definition layer is arranged on a side of the first electrode away from the second electrode, and the driving circuit layer is arranged on a side of the array definition layer away from the first electrode; The first electrodes of the light-emitting units are respectively bonded to the array definition layer, and the array definition layer is electrically connected to the driving circuit layer; the second electrodes of the light-emitting units are connected to each other.

8. A method for preparing a display panel, characterized in that: include: providing at least two light emitting unit layers stacked vertically; At least two of the light-emitting unit layers emit light of different colors; the light-emitting unit layer comprises a plurality of light-emitting units, and the light-emitting unit comprises a light-emitting portion and an electrode lead-out portion on one side of the light-emitting portion; Along the vertical stacking direction of the light-emitting unit layers, a first electrode and a second electrode are respectively formed on opposite sides of each of the electrode lead-out portions; The electrode lead-out portion of the light-emitting unit in any light-emitting unit layer does not overlap with the orthographic projection of the light-emitting unit in other light-emitting unit layers in the direction in which the light-emitting unit layers are vertically stacked.

9. The method for preparing a display panel according to claim 8, characterized in that: The method of providing at least two vertically stacked light emitting unit layers comprises: Providing an epitaxial structure on one side of the substrate; the epitaxial structure comprises at least two light-emitting unit layers stacked vertically, the light-emitting unit layer comprises a first whole semiconductor layer, a whole light-emitting layer and a second whole semiconductor layer stacked, and the light-emitting colors of the whole light-emitting layers of the light-emitting unit layers are different; Performing front-side patterning and back-side patterning on the epitaxial structure respectively, forming a first semiconductor layer, a light-emitting layer, and a second semiconductor layer of a plurality of light-emitting units in each of the light-emitting unit layers, as well as light-emitting portions and electrode lead-out portions of the plurality of light-emitting units; and / or, In the direction of vertical stacking of the light-emitting unit layer, the first electrode and the second electrode are respectively formed on opposite sides of each electrode lead-out portion, including: After front-side patterning, a first electrode is formed on a side of the first semiconductor layer of the electrode lead-out portion away from the second semiconductor layer; after back-side patterning, a second electrode is formed on a side of the second semiconductor layer of the electrode lead-out portion away from the first semiconductor layer, thereby forming a plurality of light-emitting structures.

10. The method for preparing a display panel according to claim 9, characterized in that: The step of patterning the front side and the back side of the epitaxial structure respectively comprises: Patterning the epitaxial structure to form a plurality of pixel definition grooves, and forming a first semiconductor layer, a light emitting layer, and a second semiconductor layer of a plurality of light emitting units in each of the light emitting unit layers; An isolation structure is formed in the pixel definition groove; wherein the isolation structure is disposed between adjacent light-emitting structures and is opaque to light; Patterning the light-emitting unit layer on the first surface of the epitaxial structure to form a patterned structure corresponding to the light-emitting portion and the electrode lead-out portion on the first surface of the epitaxial structure; The light-emitting unit layer is patterned on the second surface of the epitaxial structure to form a patterned structure corresponding to the light-emitting portion and the electrode lead-out portion on the second surface of the epitaxial structure, and a plurality of the light-emitting portions and the electrode lead-out portions are formed; wherein the first surface and the second surface are two opposite surfaces of the epitaxial structure; Preferably, forming an isolation structure in the pixel definition groove comprises: Depositing an insulating material on the first surface of the epitaxial structure and the inner wall of the pixel definition groove to form an insulating layer; Depositing a light-blocking material on a side of the insulating layer away from the epitaxial structure to form a light-blocking layer; The side of the epitaxial structure where the light-blocking layer is formed is planarized, and the insulating layer and the light-blocking layer in the pixel definition groove are retained to form the isolation structure.

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