Display panel and manufacturing method therefor

Abstract

The present application provides a display panel and a manufacturing method therefor. The display panel (100) comprises a substrate (1), a plurality of sub-pixels (2), a pixel defining layer (3), a cathode auxiliary layer (4), and overhang structures (5); the plurality of sub-pixels (2) are arranged on the substrate (1); each sub-pixel (2) comprises an anode electrode (21), a light emitting layer (22), and a cathode electrode (23) which are sequentially stacked on the substrate (1); the pixel defining layer (3) is arranged on the substrate (1), to define the positions of the plurality of sub-pixels (2); the cathode auxiliary layer (4) is arranged on the substrate (1) and is located between every two adjacent sub-pixels (2); the cathode electrodes (23) of every two adjacent sub-pixels (2) are electrically connected by means of the cathode auxiliary layer (4); and each overhang structure (5) is arranged on the side of the cathode auxiliary layer (4) away from the substrate (1) and is located between every two adjacent sub-pixels (2). According to the present application, a metal mask in the prior art is replaced with the overhang structures (5), so that costs can be saved, and the resolution of the display panel (100) can be further improved.

Description

Display panel and manufacturing method thereof

[0001] Cross-references

[0002] This application claims priority to Chinese patent application No. 2023111405161 filed on September 6, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of display technology, and in particular to a display panel and a method for preparing the same. Background Art

[0004] OLED (Organic Light Emitting Display) is currently the mainstream display technology. OLED display panels include active-mode OLED (AMOLED) and passive-mode OLED (PMOLED). Currently, AMOLED's organic light-emitting materials are deposited using a fine metal mask (FMM) to deposit red, green, and blue organic light-emitting materials. However, this production method suffers from high FMM costs and limited resolution, reaching a maximum of 500 PPI, for example.

[0005] Summary of the Invention

[0006] The main technical problem solved by the present application is to provide a display panel and a preparation method thereof, so as to solve the problems of low resolution and high cost of display panels in the prior art.

[0007] To solve the above technical problems, the first technical solution adopted in this application is to provide a display panel, the display panel comprising:

[0008] substrate;

[0009] A plurality of sub-pixels are provided on a substrate; each sub-pixel comprises an anode electrode, a light-emitting layer and a cathode electrode stacked in sequence on the substrate;

[0010] A pixel defining layer is provided on the substrate to define the positions of a plurality of sub-pixels;

[0011] a cathode auxiliary layer, disposed on the substrate and located between two adjacent sub-pixels; the cathode electrodes of the two adjacent sub-pixels are electrically connected via the cathode auxiliary layer;

[0012] The overhang structure is arranged on a side of the cathode auxiliary layer away from the substrate and is located between two adjacent sub-pixels.

[0013] The overhanging structure is a single negative photoresist layer and is arranged on the surface of the cathode auxiliary layer away from the substrate.

[0014] The anode electrode is arranged between the pixel defining layer and the substrate, the cathode auxiliary layer is arranged on the side of the pixel defining layer away from the substrate, and the overhang structure is arranged on the surface of the cathode auxiliary layer away from the substrate.

[0015] The anode electrode and the cathode auxiliary layer are arranged in the same layer between the pixel defining layer and the substrate. The pixel defining layer has a first opening to expose the cathode auxiliary layer. The cathode electrodes of two adjacent sub-pixels contact the cathode auxiliary layer through the first opening.

[0016] Part of the overhang structure is arranged in the first opening and is located on the surface of the cathode auxiliary layer away from the substrate, and the other part protrudes from the first opening; there is a gap between the overhang structure and the side of the first opening, and the cathode electrodes of two adjacent sub-pixels are in contact with the cathode auxiliary layer through the gap.

[0017] The projection of the overhang structure on the pixel defining layer covers the first opening.

[0018] Wherein, along the direction from the bottom to the top of the first opening, the width of the first opening and the width of the overhanging structure both gradually increase.

[0019] Wherein, the width of the gap gradually decreases along the side surface of the first opening from the bottom to the top of the first opening.

[0020] To solve the above technical problems, the second technical solution adopted in this application is to provide a method for manufacturing a display panel, which includes:

[0021] forming an anode electrode, a pixel defining layer and a cathode auxiliary layer on a substrate;

[0022] coating a negative photoresist layer on a side of the cathode auxiliary layer away from the substrate;

[0023] forming a third opening on the negative photoresist layer by exposure and development; exposing the anode electrode through the third opening, and forming an overhang structure on a sidewall of the third opening;

[0024] A light-emitting layer and a cathode electrode are deposited on the side of the anode electrode away from the substrate; the cathode electrodes of two adjacent sub-pixels are electrically connected through a cathode auxiliary layer.

[0025] The anode electrode, the pixel defining layer and the cathode auxiliary layer are formed on the substrate, including:

[0026] providing a metal layer on the substrate;

[0027] Etching the metal layer to obtain a cathode auxiliary layer and an anode electrode spaced apart from each other;

[0028] forming a pixel defining layer on a side of the cathode auxiliary layer and the anode electrode away from the substrate;

[0029] A first opening and a second opening spaced apart from each other are formed on the pixel defining layer, so that the cathode auxiliary layer is exposed through the first opening and the anode electrode is exposed through the second opening.

[0030] The beneficial effects of the present application are as follows: different from the prior art, a display panel and a preparation method thereof are provided, wherein the display panel includes a substrate, a plurality of sub-pixels, a pixel defining layer, a cathode auxiliary layer, and an overhang structure; the plurality of sub-pixels are arranged on the substrate; each sub-pixel includes an anode electrode, a light-emitting layer, and a cathode electrode stacked in sequence on the substrate; the pixel defining layer is arranged on the substrate to define the positions of the plurality of sub-pixels; the cathode auxiliary layer is arranged on the substrate and is located between two adjacent sub-pixels; the cathode electrodes of two adjacent sub-pixels are electrically connected through the cathode auxiliary layer; the overhang structure is arranged on a side of the cathode auxiliary layer away from the substrate and is located between two adjacent sub-pixels. In the present application, an overhang structure is provided on a side of the cathode auxiliary layer away from the substrate so that adjacent overhang structures can further define the sub-pixels, and the metal mask plate in the prior art can be replaced by the overhang structure, which can save costs and further improve the resolution of the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] FIG1 is a schematic structural diagram of an embodiment of a display panel provided by the present application;

[0033] FIG2 is a schematic structural diagram of another embodiment of a display panel provided by the present application;

[0034] FIG3 is a schematic structural diagram of another embodiment of a display panel provided by the present application;

[0035] FIG4 is a schematic flow chart of a method for manufacturing a display panel provided in the present application;

[0036] FIG5 is a schematic flow chart of a specific embodiment of a method for manufacturing a display panel provided in the present application;

[0037] 6( a ) to 6 ( v ) are schematic structural diagrams corresponding to the steps in the method for manufacturing a display panel provided in FIG. 5 ;

[0038] FIG7 is a schematic flow chart of another specific embodiment of the method for manufacturing a display panel provided in the present application;

[0039] 8( a ) to 8 ( f ) are schematic structural diagrams corresponding to the steps in the method for manufacturing a display panel provided in FIG. 7 ;

[0040] FIG9 is a schematic flow chart of another specific embodiment of the method for manufacturing a display panel provided in the present application;

[0041] FIG. 10( a ) to FIG. 10 ( g ) are schematic structural diagrams corresponding to the steps in the method for manufacturing the display panel provided in FIG. 9 .

[0042] In the figure: display panel 100; substrate 1; underlay 11; drive circuit layer 12; sub-pixel 2; anode electrode 21; light-emitting layer 22; cathode electrode 23; pixel defining layer 3; first opening 31; second opening 32; first conductive hole 33; second conductive hole 34; filling portion 35; protrusion 36; cathode auxiliary layer 4; overhang structure 5; upper surface 51; lower surface 52; sidewall 53; gap 54; encapsulation layer 6; filling layer 7; cover plate 8; metal layer 91; first metal layer 92; second metal layer Layer 93; negative photoresist layer 94; buffer layer 95; first sub-pixel 201; first cathode electrode 2011; red light-emitting layer 2012; first encapsulating layer 2013; first protective layer 2014; second sub-pixel 202; second cathode electrode 2021; green light-emitting layer 2022; second encapsulating layer 2023; second protective layer 2024; third sub-pixel 203; third cathode electrode 2031; blue light-emitting layer 2032; third encapsulating layer 2033; third protective layer 2034. DETAILED DESCRIPTION

[0043] The following describes the embodiments of the present application in detail with reference to the accompanying drawings.

[0044] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0045] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0046] The terms "first," "second," and "third" in this application are used only for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of such features. In the description of this application, "multiple" means at least two, for example, two, three, etc., unless otherwise specifically defined. All directional indications in the embodiments of this application (such as up, down, left, right, front, back...) are only used to explain the relative positional relationship, movement, etc. between the components under a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications also change accordingly. In addition, the terms "including" and "having," as well as 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 limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products, or devices.

[0047] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0048] To improve the resolution and reduce costs of OLED display panels, patterned manufacturing of organic light-emitting material layers has begun. A partition structure is added between each sub-pixel, and the partition structure includes an upper portion made of an inorganic insulating material and a lower portion made of an inorganic conductive material (generally a conductive metal). The cathode electrode of each sub-pixel is connected through the lower portion made of the inorganic conductive material in the partition structure, thereby achieving conduction of the cathode electrodes of each sub-pixel. However, the inorganic insulating material layer and the inorganic conductive material layer are etched using dry and wet etching methods, which requires multiple processes and is difficult to control.

[0049] Please refer to Figures 1 to 3. Figure 1 is a structural diagram of an embodiment of a display panel provided in the present application; Figure 2 is a structural diagram of another embodiment of a display panel provided in the present application; and Figure 3 is a structural diagram of yet another embodiment of a display panel provided in the present application.

[0050] In order to improve the above-mentioned problems, save costs, and improve the resolution of the display panel 100, a display panel 100 is provided in this embodiment. The display panel 100 includes a substrate 1, a plurality of sub-pixels 2, a pixel defining layer 3, a cathode auxiliary layer 4, an overhang structure 5, and an encapsulation layer 6. The plurality of sub-pixels 2 are disposed on the substrate 1; each sub-pixel 2 includes an anode electrode 21, a light-emitting layer 22, and a cathode electrode 23 stacked in sequence on the substrate 1; the pixel defining layer 3 is disposed on the substrate 1 to define the positions of the plurality of sub-pixels 2; the cathode auxiliary layer 4 is disposed on the substrate 1 and is located between two adjacent sub-pixels 2; the cathode electrodes 23 of the two adjacent sub-pixels 2 are electrically connected via the cathode auxiliary layer 4; and the overhang structure 5 is disposed on the side of the cathode auxiliary layer 4 away from the substrate 1 and is located between two adjacent sub-pixels 2.

[0051] In one embodiment, the substrate 1 includes a base 11 and a driving circuit layer 12. The display panel 100 including the base 11 and the driving circuit layer 12 is an active OLED.

[0052] In another embodiment, the substrate 1 includes a base 11. The display panel 100 having the base 11 but not including the drive circuit layer 12 is a passive OLED. The passive OLED includes a plurality of parallel and spaced anode electrodes 21 and a plurality of parallel and spaced cathode electrodes 23. The anode electrodes 21 and cathode electrodes 23 are arranged in a cross-connected manner to form an addressing circuit, which is scanned and driven by an external PCB circuit board.

[0053] The substrate 11 may be a glass substrate; or a flexible substrate, wherein the material of the flexible substrate is polyimide (PI). The driving circuit layer 12 may be a TFT circuit layer, which is used to drive the light-emitting layer 22 of the OLED. The specific TFT circuit layer includes a plurality of driving circuit units arranged in an array, and each driving circuit unit may include a thin film transistor (TFT) device and a capacitor. Each driving circuit unit corresponds to an anode electrode 21 and a light-emitting layer 22. The TFT device is a low-temperature polysilicon (LTPS) type or a metal-oxide semiconductor (MOS) type, such as a metal oxide semiconductor type of indium gallium zinc oxide (IGZO).

[0054] The display panel 100 in this embodiment is described in detail by taking an active OLED as an example.

[0055] The sub-pixel 2 in the active OLED includes an anode electrode 21 , a light-emitting layer 22 and a cathode electrode 23 which are stacked in sequence.

[0056] The anode electrode 21 is disposed between the pixel defining layer 3 and the substrate 1. Specifically, the anode electrode 21 is disposed on a surface of the TFT circuit layer away from the substrate 1. Multiple anode electrodes 21 are spaced apart and disposed on a surface of the TFT circuit layer. For example, multiple anode electrodes 21 are arranged in an array, and each anode electrode 21 corresponds to and is electrically connected to a drive circuit unit in the TFT circuit layer. Materials for the anode electrode 21 include, but are not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0057] The light-emitting layer 22 is configured to emit red, blue, or green light when powered. The light-emitting layer 22 may include one or more of a hole injection layer (HIL), a hole transfer layer (HTL), an emitter layer (EML), and an electron transfer layer (ETL).

[0058] The cathode electrode 23 is disposed on a side of the light-emitting layer 22 away from the anode electrode 21. The end of the cathode electrode 23 contacts the cathode auxiliary layer 4, so that the cathode electrodes 23 of two adjacent sub-pixels 2 are electrically connected through the cathode auxiliary layer 4. For example, the cathode electrodes 23 in the same row or column are all electrically connected through the cathode auxiliary layer 4, or all cathode electrodes 23 are electrically connected through the cathode auxiliary layer 4. The material of the cathode electrode 23 includes, but is not limited to, chromium, titanium, magnesium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials. The material of the cathode electrode 23 can be the same as or different from that of the anode electrode 21, depending on the actual situation.

[0059] The cathode auxiliary layer 4 can be disposed between the pixel defining layer 3 and the substrate 1, or on the side of the pixel defining layer 3 away from the substrate 1. Materials for the cathode auxiliary layer 4 include, but are not limited to, chromium, titanium, magnesium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0060] The overhang structure 5 is disposed on a side of the cathode auxiliary layer 4 away from the substrate 1. Specifically, the overhang structure 5 may be in contact with the cathode auxiliary layer 4. In another embodiment, when the cathode auxiliary layer 4 is disposed between the pixel defining layer 3 and the substrate 1 and the cathode auxiliary layer 4 is covered by the pixel defining layer 3, the overhang structure 5 may also be in contact with the surface of the pixel defining layer 3 away from the cathode auxiliary layer 4, and the pixel defining layer 3 has an opening spaced from the overhang structure 5, so that the cathode auxiliary layer 4 is exposed.

[0061] The overhang structure 5 includes a mutually parallel upper surface 51 and lower surface 52, and a sidewall 53 connecting the upper surface 51 and the lower surface 52. The center point of the upper surface 51 is coaxial with the center point of the lower surface 52, and the area of ​​the upper surface 51 is larger than the area of ​​the lower surface 52. In this embodiment, the sidewall 53 is a slope. The angle between the slope and the surface of the cathode auxiliary layer 4 contacting the overhang structure 5 cannot be too large. If the angle is too large, the separation effect between adjacent sub-pixels 2 will be poor. The angle between the slope and the surface of the cathode auxiliary layer 4 contacting the overhang structure 5 cannot be too small. If the angle is too small, the processing technology of the overhang structure 5 will be difficult to achieve.

[0062] In this embodiment, the angle between the inclined surface and the surface of the cathode auxiliary layer 4 is in the range of 30° to 70°. In a specific embodiment, the angle between the inclined surface and the surface of the cathode auxiliary layer 4 contacting the overhanging structure 5 is in the range of 45° to 60°. For example, the angle between the inclined surface and the surface of the cathode auxiliary layer 4 contacting the overhanging structure 5 can be 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, etc., and is set according to actual conditions.

[0063] In other embodiments, the side wall 53 may also be a curved surface. For example, the curved surface may be an outward convex curved surface or an inward concave curved surface.

[0064] The pixel defining layer 3 has a second opening 32 for exposing the anode electrode 21, so that the pixel defining layer 3 exposes the adjacent anode electrodes 21. In the present embodiment, the pixel defining layer 3 is a T-shaped structure. Specifically, the pixel defining layer 3 includes an integrally formed filling portion 35 and a protruding portion 36, the filling portion 35 is arranged between the anode electrodes 21, the protruding portion 36 is arranged on the side of the filling portion 35 away from the substrate 1, and the protruding portion 36 extends to the surface of the anode electrode 21 to cover the partially exposed surface of the anode electrode 21. Among them, the longitudinal section of the protruding portion 36 can be a rectangular structure or a trapezoidal structure. In the present embodiment, the longitudinal section of the protruding portion 36 is a trapezoidal structure, and the width of the protruding portion 36 gradually decreases along the direction from the bottom to the top of the second opening 32.

[0065] The material of the pixel defining layer 3 may be an organic material, an organic material with an inorganic coating thereon, or an inorganic material. The organic material of the pixel defining layer 3 includes, but is not limited to, polyimide. The inorganic material of the pixel defining layer 3 includes, but is not limited to, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof.

[0066] In one embodiment, referring to FIG1 , in order to save materials and simplify the process, the anode electrode 21 and the cathode auxiliary layer 4 are disposed in the same layer between the pixel defining layer 3 and the substrate 1. The pixel defining layer 3 has a second opening 32 for exposing the anode electrode 21 and a first opening 31 for exposing the cathode auxiliary layer 4. The cathode electrodes 23 of two adjacent sub-pixels 2 are in contact with the cathode auxiliary layer 4 through the first opening 31. In this embodiment, the cathode auxiliary layer 4 can be formed together during the process of manufacturing the pattern of the anode electrode 21, which simplifies the process flow. In addition, the anode electrode 21 generally uses a metal with high conductivity, such as a combination of ITO and silver, which can make the cathode auxiliary layer 4 have high conductivity, thereby reducing the resistance of the entire device and improving the display efficiency of the OLED device.

[0067] The overhang structure 5 is disposed on the surface of the cathode auxiliary layer 4 away from the substrate 1. A portion of the overhang structure 5 is disposed within the first opening 31 and is located on the surface of the cathode auxiliary layer 4 away from the substrate 1, while another portion protrudes beyond the first opening 31. A gap 54 is defined between the overhang structure 5 and the side of the first opening 31. The cathode electrodes 23 of two adjacent sub-pixels 2 contact the cathode auxiliary layer 4 through the gap 54.

[0068] In this embodiment, the projection of the overhang structure 5 on the pixel defining layer 3 covers the first opening 31. Thus, when evaporating the organic light-emitting material, vertical evaporation is employed, and the deposited organic material is blocked by the upper surface 51 of the overhang structure 5 and prevented from being deposited on the cathode auxiliary layer 4 at the first opening 31, thereby preventing obstruction of the subsequent electrical connection between the cathode electrode 23 and the cathode auxiliary layer 4. However, when evaporating the cathode electrode 23, an inclined evaporation angle is employed, allowing the cathode electrode 23 to be deposited on the cathode auxiliary layer 4 at the first opening 31, thereby achieving electrical connection between the cathode electrode 23 and the cathode auxiliary layer 4. The area of ​​the lower surface 52 of the overhang structure 5 is smaller than the area of ​​the surface of the cathode auxiliary layer 4 contacting the overhang structure 5.

[0069] Along the direction from the bottom to the top of the first opening 31 , the width of the first opening 31 , the width of the second opening 32 and the width of the overhanging structure 5 all gradually increase.

[0070] To minimize the deposition of organic light-emitting material onto the cathode auxiliary layer 4, the width of the gap 54 gradually decreases along the side of the first opening 31 from the bottom to the top of the first opening 31. In another embodiment, the width of the gap 54 remains constant along the side of the first opening 31 from the bottom to the top of the first opening 31. In another embodiment, to facilitate the formation of the cathode electrode 23 by evaporation, the width of the gap 54 gradually increases along the side of the first opening 31 from the bottom to the top of the first opening 31.

[0071] In another embodiment, the anode electrode 21 and the cathode auxiliary layer 4 are disposed in the same layer between the pixel defining layer 3 and the substrate 1. Referring to FIG. 2 , the pixel defining layer 3 covers the cathode auxiliary layer 4 and has a second opening 32 that exposes the anode electrode 21. The pixel defining layer 3 is provided with a first conductive hole 33 and a second conductive hole 34 that are spaced apart from each other. The first conductive hole 33 and the second conductive hole 34 expose a portion of the surface of the cathode auxiliary layer 4. The cathode electrodes 23 of two adjacent sub-pixels 2 contact the cathode auxiliary layer 4 through the first conductive hole 33 and the second conductive hole 34.

[0072] The overhang structure 5 is disposed on the surface of the pixel defining layer 3 away from the substrate 1. The overhang structure 5 is disposed between the first and second via holes 33 and 34, and the orthographic projection of the overhang structure 5 on the substrate 1 overlaps the orthographic projections of the first and second via holes 33 and 34 on the substrate 1. The shapes and sizes of the first and second via holes 33 and 34 may be the same or different. The cross-sectional shapes of the first and second via holes 33 and 34 may be rectangular, semi-circular, or annular, etc. In this embodiment, the first and second via holes 33 and 34 are both circular. In one embodiment, the sizes of the first and second via holes 33 and 34 gradually increase from the bottom to the top of the second opening 32. In another embodiment, the sizes of the first and second via holes 33 and 34 remain constant from the bottom to the top of the second opening 32. In another embodiment, the sizes of the first and second via holes 33 and 34 gradually decrease from the bottom to the top of the second opening 32.

[0073] In this embodiment, the auxiliary layer of the anode electrode 21 and the anode electrode 21 are made of the same material and are manufactured in the same process.

[0074] In the above embodiment, the overhang structure 5 can be a single-layer structure. Specifically, the material of the overhang structure 5 can be a non-conductive organic material or a non-conductive inorganic material. The non-conductive inorganic material includes, but is not limited to, an inorganic silicon-containing material. For example, the silicon-containing material includes silicon oxide or nitride, or a combination thereof. The non-conductive organic material includes a negative photosensitive organic material. For example, the negative photosensitive organic material includes, but is not limited to, a negative photoresist.

[0075] During the exposure process, the exposed portions of the negative photoresist polymerize and crosslink, while the unexposed portions remain unchanged. The surface of the negative photoresist is more susceptible to crosslinking. The intensity of illumination decreases as the negative photoresist moves further away from the surface. The degree of crosslinking decreases as the negative photoresist moves further away from the surface. During the development process, the uncrosslinked negative photoresist is washed away, resulting in an inverted trapezoidal overhang 5.

[0076] The overhang structure 5 with a single-layer structure is manufactured based on a negative photoresist by adopting an exposure and development method, which only requires one exposure and development, and the process is simpler.

[0077] In another embodiment, the overhang structure 5 includes an upper portion and a lower portion connected to each other. The upper portion and the lower portion may be made of the same material or different materials. The upper portion and the lower portion may be made of at least one of a non-conductive inorganic material and a non-conductive organic material.

[0078] When the cathode auxiliary layer 4 and the anode electrode 21 are provided on the same layer, the metal layer 91 forming the cathode auxiliary layer 4 and the anode electrode 21 can be provided wider and larger in size, and the pixel defining layer 3 can be used to control the size of the area of ​​the cathode auxiliary layer 4 in contact with the cathode electrode 23. By providing the cathode auxiliary layer 4 and the anode electrode 21 on the same layer, and using a single-layer structure and directly providing the overhang structure 5 on the surface of the cathode auxiliary layer 4, the thickness of the display panel can be reduced.

[0079] In order to facilitate contact between the cathode electrode 23 and the cathode auxiliary layer 4 and reduce the risk of fracture of the cathode electrode 23, in one embodiment, referring to FIG3 , the anode electrode 21 and the cathode auxiliary layer 4 are provided in different layers, eliminating the step structure between the pixel defining layer 3 and the cathode auxiliary layer 4, thereby facilitating contact between the cathode electrode 23 and the cathode auxiliary layer 4.

[0080] Specifically, referring to FIG3 , the anode electrode 21 is disposed between the pixel-defining layer 3 and the substrate 1. The pixel-defining layer 3 is provided with a second opening 32 exposing the anode electrode 21. The cathode auxiliary layer 4 is disposed on the side of the pixel-defining layer 3 away from the substrate 1. That is, the distance between the cathode auxiliary layer 4 and the substrate 1 is greater than the distance between the anode electrode 21 and the substrate 1. Specifically, the cathode auxiliary layer 4 is in contact with the pixel-defining layer 3. The orthographic projection of the cathode auxiliary layer 4 on the substrate 1 is spaced apart from the orthographic projection of the anode electrode 21 on the substrate 1.

[0081] In one embodiment, the overhang structure 5 is disposed on a surface of the cathode auxiliary layer 4 away from the substrate 1, and the overhang structure 5 contacts the cathode auxiliary layer 4. The width of the overhang structure 5 gradually increases from the bottom to the top of the second opening 32. For example, the longitudinal cross-section of the overhang structure 5 is an inverted trapezoidal structure.

[0082] The area of ​​the lower surface 52 of the overhanging structure 5 is smaller than the area of ​​the surface of the cathode auxiliary layer 4 contacting the overhanging structure 5 .

[0083] In this embodiment, the overhang structure 5 is a single-layer structure. Specifically, the material of the overhang structure 5 can be a non-conductive organic material. The non-conductive organic material includes a negative photosensitive organic material. For example, the negative photosensitive organic material includes but is not limited to a negative photoresist.

[0084] In one embodiment, the orthographic projection of the overhang structure 5 on the pixel defining layer 3 covers the orthographic projection of the cathode auxiliary layer 4 on the pixel defining layer 3 .

[0085] In another embodiment, the encapsulation layer 6 is disposed on a surface of the cathode electrode 23 that is away from the light-emitting layer 22, such that the encapsulation layer 6 covers the exposed surface of the sub-pixel 2 and the overhang structure 5. Specifically, the encapsulation layer 6 covers the exposed surface of the cathode electrode 23 and extends along the sidewall 53 of the overhang structure 5, such that the encapsulation layer 6 encapsulates the exposed surface of the overhang structure 5. The encapsulation layer 6 includes a non-conductive inorganic material, wherein the non-conductive inorganic material includes a silicon-containing material. The silicon-containing material may include a Si3N4-containing material.

[0086] In this embodiment, the light-emitting layer 22 , the cathode electrode 23 and the encapsulation layer 6 are formed by stacking them layer by layer in sequence by means of evaporation.

[0087] In one embodiment, the display panel 100 further includes a filling layer 7 and a cover plate 8. The filling layer 7 fills the recessed area of ​​each sub-pixel 2, so that the sub-pixel 2 is away from the surface of the substrate 1 to form a flat surface, which facilitates the cover plate 8 to cover the surface of the sub-pixel 2. The filling layer 7 is made of a transparent material. The cover plate 8 can be a glass cover plate or a plastic film such as PET.

[0088] The display panel provided in this embodiment includes a substrate, a plurality of sub-pixels, a pixel defining layer, a cathode auxiliary layer, and an overhang structure; the plurality of sub-pixels are arranged on the substrate; each sub-pixel includes an anode electrode, a light-emitting layer, and a cathode electrode stacked in sequence on the substrate; the pixel defining layer is arranged on the substrate to define the positions of the plurality of sub-pixels; the cathode auxiliary layer is arranged on the substrate and is located between two adjacent sub-pixels; the cathode electrodes of two adjacent sub-pixels are electrically connected through the cathode auxiliary layer; the overhang structure is arranged on a side of the cathode auxiliary layer away from the substrate and is located between two adjacent sub-pixels. In the present application, an overhang structure is provided on a side of the cathode auxiliary layer away from the substrate so that adjacent overhang structures can further define the sub-pixels, and the metal mask plate in the prior art can be replaced by the overhang structure, which can save costs and further improve the resolution of the display panel.

[0089] Please refer to FIG. 4 , which is a schematic flow chart of a method for manufacturing a display panel provided in this application.

[0090] This embodiment provides a method for manufacturing a display panel 100 , and the method for manufacturing the display panel 100 includes the following steps.

[0091] S1: forming an anode electrode, a pixel defining layer and a cathode auxiliary layer on a substrate.

[0092] S2: coating a negative photoresist layer on the side of the cathode auxiliary layer away from the substrate.

[0093] S3: forming a third opening on the negative photoresist layer by exposure and development, wherein the third opening exposes the anode electrode, and a sidewall of the third opening forms an overhang structure.

[0094] S4: depositing a light-emitting layer and a cathode electrode on a side of the anode electrode away from the substrate, and electrically connecting the cathode electrodes of two adjacent sub-pixels via a cathode auxiliary layer.

[0095] In this embodiment, an overhang structure made of a negative photoresist layer is provided on the side of the cathode auxiliary layer away from the substrate, so that the adjacent overhang structure can further define the light-emitting layer. The overhang structure can replace the metal mask plate in the prior art, which can save costs and further improve the resolution of the display panel.

[0096] Please refer to Figures 5 and 6(a) to 6(v). Figure 5 is a flow chart of a specific embodiment of the method for preparing a display panel provided in the present application; Figures 6(a) to 6(v) are structural schematic diagrams corresponding to each step in the method for preparing a display panel provided in Figure 5.

[0097] In one embodiment, obtaining the display panel 100 in which the anode electrode 21 and the cathode auxiliary layer 4 are arranged in the same layer specifically includes the following steps.

[0098] S11: Disposing a metal layer on the substrate.

[0099] Specifically, a substrate 1 is obtained, wherein the substrate 1 includes a base 11 and a driving circuit layer 12. The display panel 100 having the base 11 and the driving circuit layer 12 is an active OLED.

[0100] In another embodiment, the substrate 1 includes a base 11. The display panel 100 having the base 11 but not including the driving circuit layer 12 is a passive OLED.

[0101] The substrate 11 may be a glass substrate or a flexible substrate, wherein the flexible substrate is made of polyimide (PI). The driving circuit layer 12 may be a TFT circuit layer, which is used to drive the light-emitting layer 22 of the OLED. The TFT circuit layer includes a plurality of TFT devices arranged in an array, and the TFT devices are arranged in a one-to-one correspondence with the light-emitting layer 22. The TFT devices are low-temperature polysilicon (LTPS) type or metal-oxide semiconductor (MOS) type, such as indium gallium zinc oxide (IGZO) metal oxide semiconductor type.

[0102] The display panel 100 in this embodiment is described in detail by taking an active OLED as an example.

[0103] The surface of the driving circuit layer 12 away from the substrate 11 is covered with a metal layer 91, as shown in FIG6(a). The material of the metal layer 91 includes but is not limited to chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof or other suitable conductive materials.

[0104] S12: etching the metal layer to obtain a cathode auxiliary layer and an anode electrode spaced apart from each other.

[0105] Specifically, the metal layer 91 is patterned by wet etching or dry etching to obtain a cathode auxiliary layer 4 and an anode electrode 21 spaced apart from each other, as shown in FIG6(b). Dry etching includes laser etching or plasma etching. Wet etching includes chemical etching.

[0106] S13: forming a pixel defining layer on a side of the cathode auxiliary layer and the anode electrode away from the substrate.

[0107] Specifically, a pixel defining layer 3 is formed on the side of the cathode auxiliary layer 4 and the anode electrode 21 away from the substrate 1, as shown in Figure 6(c). The material of the pixel defining layer 3 can be an organic material, an organic material with an inorganic coating provided thereon, or an inorganic material. The organic material of the pixel defining layer 3 includes, but is not limited to, polyimide. The inorganic material of the pixel defining layer 3 includes, but is not limited to, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or a combination thereof.

[0108] S14: forming a first opening and a second opening spaced apart from each other on the pixel defining layer.

[0109] Specifically, a mask is placed on the surface of the pixel-defining layer 3 away from the substrate 1. A first opening 31 and a second opening 32 are formed in the pixel-defining layer 3 by dry etching, so that the cathode auxiliary layer 4 is exposed through the first opening 31 and the anode electrode 21 is exposed through the second opening 32, as shown in FIG6(d). The mask is then removed. The pixel-defining layer 3 defines the anode electrode 21 to form the sub-pixel 2.

[0110] S15: coating a negative photoresist layer on a side of the cathode auxiliary layer away from the substrate.

[0111] Specifically, a negative photoresist layer 94 is disposed on the side of the cathode auxiliary layer 4 away from the substrate 1, and the negative photoresist layer 94 fills the first opening 31 and the second opening 32. The surface of the negative photoresist layer 94 away from the substrate 1 is flat, as shown in FIG6(e).

[0112] S16: The negative photoresist layer is formed into an overhang structure by exposure and development.

[0113] Specifically, during the exposure process, the portions of negative photoresist layer 94 exposed to light polymerize and crosslink, while the portions not exposed to light do not crosslink. The surface of negative photoresist layer 94 is more susceptible to crosslinking. The intensity of light gradually decreases as the portions of negative photoresist layer 94 further from the surface become more sparse. As the negative photoresist layer 94 moves further from the surface, the degree of crosslinking and polymerization of the negative photosensitive material decreases. During the development process, the uncrosslinked portions of negative photoresist are washed away.

[0114] A mask is applied to the surface of the negative photoresist layer 94 facing away from the substrate 1. Exposure to light causes crosslinking and polymerization of the exposed portion of the negative photoresist layer 94, while the unexposed portion of the negative photoresist layer 94 remains unpolymerized. After a predetermined exposure time, the unpolymerized crosslinked negative photoresist is removed with a developer, resulting in an inverted trapezoidal overhang structure 5. A gap 54 is formed between the sidewalls 53 of the overhang structure 5 and the pixel-defining layer 3, as shown in FIG6(f).

[0115] S17: depositing a light-emitting layer, a cathode electrode and an encapsulation layer on a side of the anode electrode away from the substrate.

[0116] Specifically, because different sub-pixels 2 emit light of different colors, the materials of the light-emitting layers 22 in different sub-pixels 2 differ, necessitating the production of sub-pixels 2 emitting light of different colors in different steps. The light-emitting layers 22 include, but are not limited to, a red light-emitting layer 2012, a green light-emitting layer 2022, and a blue light-emitting layer 2032. The order in which the red light-emitting layer 2012, the green light-emitting layer 2022, and the blue light-emitting layer 2032 are formed can be determined based on actual circumstances. For example, the red light-emitting layer 2012 can be formed first, followed by the green light-emitting layer 2022, and finally the blue light-emitting layer 2032.

[0117] In the following embodiment, sub-pixels 2 emitting red light are prepared first, followed by sub-pixels 2 emitting green light, and finally sub-pixels 2 emitting blue light. The sub-pixels 2 on which the red light-emitting layer 2012 is to be formed are collectively referred to as first sub-pixels 201, the sub-pixels 2 on which the green light-emitting layer 2022 is to be formed are collectively referred to as second sub-pixels 202, and the sub-pixels 2 on which the blue light-emitting layer 2032 is to be formed are collectively referred to as third sub-pixels 203.

[0118] In one specific embodiment, before forming the red light emitting layer 22 in the first sub-pixel 201, a buffer layer 95 is first filled in the second sub-pixel 202 and the third sub-pixel 203, respectively. The buffer layer 95 is used to protect the anode electrode 21 in the second sub-pixel 202 and the anode electrode 21 in the third sub-pixel 203, as shown in FIG6(g). The material of the buffer layer 95 can be silicon nitride. The thickness of the buffer layer 95 in the third sub-pixel 203 is greater than that of the buffer layer 95 in the second sub-pixel 202.

[0119] First, a red organic light-emitting material is evaporated to form a red light-emitting layer 2012. The red light-emitting layer 2012 is formed on the surface of the anode electrode 21 facing away from the substrate 1. The red light-emitting layer 2012 covers the surface of the overhang structure 5 facing away from the substrate 1, as well as the exposed surface of the anode electrode 21 in the first sub-pixel 201 and the exposed surface of the buffer layer 95 in the second sub-pixel 202 and the third sub-pixel 203.

[0120] Then, a metal material is evaporated to form a first cathode electrode 2011. The first cathode electrode 2011 is formed on the surface of the red light-emitting layer 2012 away from the substrate 1. The first cathode electrode 2011 covers the red light-emitting layer 2012 on the overhang structure 5 and the red light-emitting layer 2012 on the anode electrode 21. The first cathode electrode 2011 on the red light-emitting layer 2012 corresponding to the anode electrode 21 extends along the pixel defining layer 3 to the gap 54 formed between the overhang structure 5 and the pixel defining layer 3, and contacts the exposed cathode auxiliary layer 4.

[0121] Finally, an inorganic silicon-containing material is evaporated to form a first encapsulating layer 2013. The first encapsulating layer 2013 is formed on the surface of the first cathode electrode 2011 away from the substrate 1. The first encapsulating layer 2013 covers the first cathode electrode 2011 and all exposed surfaces of the overhanging structure 5, thereby producing a first sub-pixel 201 capable of emitting red light, as shown in FIG6(h).

[0122] In order to protect the first sub-pixel 201, a first protective layer 2014 is filled in the first sub-pixel 201 so that the first protective layer 2014 fills the recessed area of ​​the first sub-pixel 201 and covers the exposed surface of the first encapsulation layer 2013 on the overhang structure 5 on both sides of the first sub-pixel 201, as shown in Figure 6(i).

[0123] By dry etching or wet etching, the first encapsulation layer 2013, the first cathode electrode 2011 and the red light-emitting layer 2012 on the second sub-pixel 202, the third sub-pixel 203 and the overhang structure 5 that are not provided with the first protective layer 2014 are all removed to expose the buffer layer 95 in the second sub-pixel 202 and the third sub-pixel 203, as shown in Figure 6(j).

[0124] The buffer layer 95 in the second sub-pixel 202 is removed by dry etching to expose the anode electrode 21 in the second sub-pixel 202. At the same time, the buffer layer 95 in the third sub-pixel 203 is thinned, as shown in FIG6(k).

[0125] The first protection layer 2014 is removed by dry etching or wet etching to expose the first encapsulation layer 2013, as shown in FIG6(l).

[0126] First, a green organic light-emitting material is evaporated to form a green light-emitting layer 2022 . The green light-emitting layer 2022 is formed on a side of the anode electrode 21 away from the substrate 1 .

[0127] Then, a metal material is evaporated to form the second cathode electrode 2021 . The second cathode electrode 2021 is formed on a surface of the green light emitting layer 2022 that is away from the substrate 1 .

[0128] Finally, an inorganic silicon-containing material is evaporated to form a second encapsulating layer 2023. The second encapsulating layer 2023 is formed on the surface of the second cathode electrode 2021 away from the substrate 1. The second encapsulating layer 2023 covers the second cathode electrode 2021 and all exposed surfaces of the overhanging structure 5, thereby producing a second sub-pixel 202 that can emit green light, as shown in FIG6(m).

[0129] In order to protect the second sub-pixel 202, a second protective layer 2024 is filled in the second sub-pixel 202 so that the second protective layer 2024 fills the recessed area of ​​the second sub-pixel 202 and covers the exposed surface of the second encapsulation layer 2023 on the overhang structure 5 on both sides of the second sub-pixel 202, as shown in Figure 6(n).

[0130] By dry etching or wet etching, the first sub-pixel 201, the third sub-pixel 203 and the second encapsulation layer 2023, the second cathode electrode 2021, and the green light-emitting layer 2022 on the overhang structure 5 without the second protective layer 2024 are all removed to expose the first encapsulation layer 2013 and the buffer layer 95 in the third sub-pixel 203, as shown in Figure 6(o).

[0131] The second protection layer 2024 is removed by dry etching or wet etching to expose the second encapsulation layer 2023 , as shown in FIG6( p ).

[0132] The buffer layer 95 in the third sub-pixel 203 is removed by dry etching, so that the anode electrode 21 in the third sub-pixel 203 is exposed, as shown in FIG6(q).

[0133] First, a blue organic light-emitting material is evaporated to form a blue light-emitting layer 2032 . The blue light-emitting layer 2032 is formed on a side of the anode electrode 21 away from the substrate 1 .

[0134] Then, a metal material is evaporated to form a third cathode electrode 2031 . The third cathode electrode 2031 is formed on a side of the blue light emitting layer 2032 away from the substrate 1 .

[0135] Finally, an inorganic silicon-containing material is evaporated to form a third encapsulating layer 2033. The third encapsulating layer 2033 is formed on the surface of the third cathode electrode 2031 away from the substrate 1. The third encapsulating layer 2033 covers the third cathode electrode 2031 and all exposed surfaces of the overhanging structure 5, thereby producing a third sub-pixel 203 capable of emitting blue light, as shown in FIG6(r).

[0136] In order to protect the third sub-pixel 203, a third protective layer 2034 is filled in the third sub-pixel 203 so that the third protective layer 2034 fills the recessed area of ​​the third sub-pixel 203 and covers the exposed surface of the third encapsulation layer 2033 on the overhang structure 5 on both sides of the third sub-pixel 203, as shown in Figure 6(s).

[0137] By dry etching or wet etching, the third encapsulation layer 2033, the third cathode electrode 2031, and the blue light-emitting layer 2032 on the first sub-pixel 201, the second sub-pixel 202, and the overhang structure 5 where the third protective layer 2034 is not provided are all removed to expose the first encapsulation layer 2013 and the second encapsulation layer 2023, as shown in FIG6(t).

[0138] The third protection layer 2034 in the third sub-pixel 203 is removed by dry etching, so that the third encapsulation layer 2033 in the third sub-pixel 203 is exposed, as shown in FIG6(u).

[0139] Among them, the first cathode electrode 2011 in the first sub-pixel 201 is conductively connected to the second cathode electrode 2021 in the second sub-pixel 202 through the cathode auxiliary layer 4 between the first sub-pixel 201 and the second sub-pixel 202, the second cathode electrode 2021 in the second sub-pixel 202 is conductively connected to the third cathode electrode 2031 in the third sub-pixel 203 through the cathode auxiliary layer 4 between the second sub-pixel 202 and the third sub-pixel 203, and the first cathode electrode 2011 in the first sub-pixel 201 is conductively connected to the third cathode electrode 2031 in the third sub-pixel 203 through the cathode auxiliary layer 4 between the first sub-pixel 201 and the third sub-pixel 203.

[0140] A filling layer 7 is provided on the side of the first sub-pixel 201, the second sub-pixel 202, and the third sub-pixel 203 away from the substrate 1, so that the filling layer 7 fills the recessed areas of the first sub-pixel 201, the second sub-pixel 202, and the third sub-pixel 203, and the surface of the filling layer 7 away from the substrate 1 is flat. A cover plate 8 is provided on the surface of the filling layer 7 away from the substrate 1 to cover the first sub-pixel 201, the second sub-pixel 202, and the third sub-pixel 203, as shown in FIG6(v). The material of the filling layer 7 is a transparent material. The cover plate 8 can be a glass cover plate 8, or a plastic film such as PET.

[0141] Please refer to Figures 7 and 8(a) to 8(f). Figure 7 is a flow chart of another specific embodiment of the method for preparing a display panel provided in the present application; Figures 8(a) to 8(f) are structural schematic diagrams corresponding to each step in the method for preparing a display panel provided in Figure 7.

[0142] In one embodiment, obtaining the display panel 100 in which the anode electrode 21 and the cathode auxiliary layer 4 are arranged in the same layer specifically includes the following steps.

[0143] S21: Disposing a metal layer on the substrate.

[0144] S22: Etching the metal layer to obtain a cathode auxiliary layer and an anode electrode spaced apart from each other.

[0145] S23: forming a pixel defining layer on a side of the cathode auxiliary layer and the anode electrode away from the substrate.

[0146] Specifically, the specific implementation of steps S21 to S23 in this embodiment is the same as that of steps S11 to S13 in the above embodiment, and will not be repeated here.

[0147] S24: forming a first conductive hole and a second conductive hole on the pixel defining layer to expose a portion of the cathode auxiliary layer.

[0148] Specifically, a first conductive hole 33 and a second conductive hole 34 are formed on the pixel defining layer 3 by dry etching. There may be multiple first conductive holes 33 and second conductive holes 34. A group of first conductive holes 33 and second conductive holes 34 corresponds to the same cathode auxiliary layer 4, so that a portion of the surface of the same cathode auxiliary layer 4 is exposed, as shown in FIG8(a). The projections of the first conductive holes 33 and the second conductive holes 34 on the substrate 1 do not exceed the projection of the cathode auxiliary layer 4 on the substrate 1.

[0149] S25: coating a negative photoresist layer on a side of the pixel defining layer away from the substrate.

[0150] Specifically, a negative photoresist layer 94 is provided on the side of the pixel defining layer 3 away from the substrate 1, and the negative photoresist layer 94 fills the first conductive hole 33 and the second conductive hole 34. The surface of the negative photoresist layer 94 away from the substrate 1 is flat, as shown in FIG8(b).

[0151] S26: The negative photoresist layer is formed into an overhang structure by exposure and development.

[0152] Specifically, as shown in FIG8( c ), the specific implementation of step S26 in this embodiment is the same as step S16 in the above embodiment, and will not be repeated here.

[0153] S27: forming a second opening on the pixel defining layer, so that the anode electrode is exposed through the second opening.

[0154] Specifically, as shown in FIG8( d ), the specific implementation of step S27 in this embodiment is the same as step S14 in the above embodiment, and will not be repeated here.

[0155] S28: depositing a light-emitting layer, a cathode electrode and an encapsulation layer in sequence on a side of the anode electrode away from the substrate.

[0156] Specifically, as shown in FIG8( e ), the specific implementation of step S28 in this embodiment is the same as step S17 in the above embodiment, and will not be repeated here.

[0157] In another embodiment, step S24 may be modified to include forming a first conductive hole 33, a second conductive hole 34, and a second opening 32 on the pixel defining layer 3, such that a portion of the cathode auxiliary layer 4 is exposed through the first conductive hole 33 and the second conductive hole 34, and the anode electrode 21 is exposed through the second opening 32, as shown in FIG8(f). Steps S25, S26, and S28 are then performed sequentially.

[0158] Please refer to Figure 9 and Figures 10(a) to 10(g). Figure 9 is a flow chart of another specific embodiment of the method for preparing a display panel provided in the present application; Figures 10(a) to 10(g) are structural schematic diagrams corresponding to each step in the method for preparing a display panel provided in Figure 9.

[0159] In one embodiment, obtaining the display panel 100 in which the anode electrode 21 and the cathode auxiliary layer 4 are not arranged in the same layer specifically includes the following steps.

[0160] S31: Disposing a first metal layer on a substrate.

[0161] Specifically, a substrate 1 is obtained. The substrate 1 includes a base 11 and a driving circuit layer 12. The display panel 100 having the base 11 and the driving circuit layer 12 is an active OLED. In another embodiment, the substrate 1 includes the base 11. The display panel 100 having the base 11 but not the driving circuit layer 12 is a passive OLED.

[0162] The display panel 100 in this embodiment is described in detail by taking an active OLED as an example.

[0163] The surface of the driving circuit layer 12 away from the substrate 11 is covered with a first metal layer 92, as shown in FIG10(a). The material of the first metal layer 92 includes but is not limited to chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0164] S32: Etching the first metal layer to obtain an anode electrode.

[0165] Specifically, the specific implementation of forming the anode electrode 21 in step S32 of this embodiment is the same as the specific implementation steps of forming the anode electrode 21 in step S12 of the above embodiment, as shown in FIG10( b ), and will not be repeated here.

[0166] S33: forming a pixel defining layer and a second metal layer in sequence on a side of the anode electrode away from the substrate.

[0167] Specifically, the specific implementation of forming the pixel defining layer 3 in this embodiment is the same as the method of forming the pixel defining layer 3 in the above step S13, as shown in FIG10( c ), and will not be repeated here.

[0168] A second metal layer 93 is covered on the side of the pixel defining layer 3 away from the substrate 1, as shown in FIG10(d). The material of the second metal layer 93 can be the same as or different from that of the first metal layer 92.

[0169] S34: patterning the second metal layer to obtain a cathode auxiliary layer.

[0170] Specifically, the specific implementation of forming the cathode auxiliary layer 4 in step S34 of this embodiment is the same as the specific implementation of forming the cathode auxiliary layer 4 in step S12 of the above embodiment, as shown in FIG10( e ), and will not be repeated here.

[0171] S35: forming a second opening on the exposed pixel defining layer to expose the anode electrode.

[0172] Specifically, the specific implementation of forming the second opening 32 in step S35 of this embodiment is the same as the specific implementation of forming the second opening 32 in step S14 of the above embodiment, as shown in FIG10( f ), and will not be repeated here.

[0173] S36: coating a negative photoresist layer on a side of the cathode auxiliary layer away from the substrate.

[0174] S37: The negative photoresist layer is formed into an overhang structure by exposure and development.

[0175] S38: depositing a light-emitting layer and a cathode electrode on a side of the anode electrode away from the substrate.

[0176] Specifically, the specific implementation of step S37 and step S38 in this embodiment is the same as the specific implementation of step S16 and step S17 in the above embodiment, as shown in Figure 10(g), and will not be repeated here.

[0177] The method for preparing a display panel provided in this embodiment sets an overhang structure on the side of the cathode auxiliary layer away from the substrate so that adjacent overhang structures can further define sub-pixels. The overhang structure can replace the metal mask plate in the prior art, which can save costs and further improve the resolution of the display panel.

[0178] The above is only an implementation method of the present application and does not limit the scope of patent protection of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection of the present application.

Claims

1. A display panel, wherein: include: substrate; A plurality of sub-pixels are arranged on the substrate; each of the sub-pixels comprises an anode electrode, a light-emitting layer and a cathode electrode which are sequentially stacked on the substrate; A pixel defining layer, disposed on the substrate, defining positions of a plurality of sub-pixels; a cathode auxiliary layer, disposed on the substrate and located between two adjacent sub-pixels; cathode electrodes of the two adjacent sub-pixels are electrically connected via the cathode auxiliary layer; The overhang structure is arranged on a side of the cathode auxiliary layer away from the substrate and is located between two adjacent sub-pixels.

2. The display panel according to claim 1, wherein: The overhanging structure is a single negative photoresist layer and is arranged on a surface of the cathode auxiliary layer away from the substrate.

3. The display panel according to claim 2, wherein: The anode electrode is arranged between the pixel defining layer and the substrate, the cathode auxiliary layer is arranged on a side of the pixel defining layer away from the substrate, and the overhanging structure is arranged on a surface of the cathode auxiliary layer away from the substrate.

4. The display panel according to claim 1, wherein: The anode electrode and the cathode auxiliary layer are arranged in the same layer between the pixel defining layer and the substrate, and the pixel defining layer has a first opening to expose the cathode auxiliary layer; the cathode electrodes of two adjacent sub-pixels contact the cathode auxiliary layer through the first opening.

5. The display panel according to claim 4, wherein: A portion of the overhang structure is arranged in the first opening and is located on the surface of the cathode auxiliary layer away from the substrate, and the other portion protrudes from the first opening; there is a gap between the overhang structure and the side of the first opening, and the cathode electrodes of two adjacent sub-pixels are in contact with the cathode auxiliary layer through the gap.

6. The display panel according to claim 5, wherein: A projection of the overhang structure on the pixel defining layer covers the first opening.

7. The display panel according to claim 5, wherein: Along the direction from the bottom to the top of the first opening, the width of the first opening and the width of the overhanging structure both gradually increase.

8. The display panel according to claim 7, wherein: The width of the gap gradually decreases along the side of the first opening from the bottom to the top of the first opening.

9. The display panel according to claim 1, wherein: The anode electrode and the cathode auxiliary layer are arranged in the same layer between the pixel defining layer and the substrate, the pixel defining layer covers the cathode auxiliary layer, and the pixel defining layer is provided with a first conductive hole and a second conductive hole spaced apart from each other and exposing a portion of the cathode auxiliary layer, and the cathode electrodes of two adjacent sub-pixels are in contact with the cathode auxiliary layer through the first conductive hole and the second conductive hole.

10. The display panel according to claim 1, wherein: An area of ​​a lower surface of the overhang structure is smaller than an area of ​​an upper surface of the cathode auxiliary layer in contact with the overhang structure.

11. The display panel according to claim 1, wherein: The overhang structure includes an upper surface and a lower surface parallel to each other, and a side wall connecting the upper surface and the lower surface, wherein the side wall is an inclined surface, and an angle between the inclined surface and the surface of the cathode auxiliary layer ranges from 30° to 70°.

12. A method for preparing a display panel, wherein: The method for preparing the display panel includes: forming an anode electrode, a pixel defining layer and a cathode auxiliary layer on a substrate; Coating a negative photoresist layer on a side of the cathode auxiliary layer away from the substrate; Forming a third opening on the negative photoresist layer by exposure and development; the third opening exposes the anode electrode, and a sidewall of the third opening forms an overhang structure; A light emitting layer and a cathode electrode are deposited on a side of the anode electrode away from the substrate; the cathode electrodes of two adjacent sub-pixels are electrically connected through the cathode auxiliary layer.

13. The method for preparing a display panel according to claim 12, wherein: The step of forming an anode electrode, a pixel defining layer and a cathode auxiliary layer on a substrate comprises: providing a metal layer on the substrate; Etching the metal layer to obtain the cathode auxiliary layer and the anode electrode spaced apart from each other; forming the pixel defining layer on a side of the cathode auxiliary layer and the anode electrode away from the substrate; A first opening and a second opening spaced apart from each other are formed on the pixel defining layer, so that the cathode auxiliary layer is exposed through the first opening, and the anode electrode is exposed through the second opening.

14. The method for preparing a display panel according to claim 12, wherein: The step of forming an anode electrode, a pixel defining layer and a cathode auxiliary layer on a substrate comprises: providing a metal layer on the substrate; Etching the metal layer to obtain the cathode auxiliary layer and the anode electrode spaced apart from each other; forming the pixel defining layer on a side of the cathode auxiliary layer and the anode electrode away from the substrate; A first conductive hole and a second conductive hole are formed on the pixel defining layer, so that a portion of the cathode auxiliary layer is exposed through the first conductive hole and the second conductive hole.

15. The method for preparing a display panel according to claim 12, wherein: The step of forming an anode electrode, a pixel defining layer and a cathode auxiliary layer on a substrate comprises: Disposing a first metal layer on the substrate; Etching the first metal layer to obtain the anode electrode; forming the pixel defining layer and the second metal layer in sequence on a side of the anode electrode away from the substrate; patterning the second metal layer to obtain the cathode auxiliary layer; A second opening is formed on the exposed pixel defining layer to expose the anode electrode.

16. The method for preparing a display panel according to claim 12, wherein: An area of ​​a lower surface of the overhang structure is smaller than an area of ​​an upper surface of the cathode auxiliary layer in contact with the overhang structure.

17. The method for preparing a display panel according to claim 12, wherein: The overhang structure includes an upper surface and a lower surface parallel to each other, and a side wall connecting the upper surface and the lower surface, wherein the side wall is an inclined surface, and an angle between the inclined surface and the surface of the cathode auxiliary layer ranges from 30° to 70°.

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