Display panel and method for preparing the same

Abstract

The present application discloses a display panel and a method for manufacturing a display panel. In the surface cathode overlapping region, the display panel includes an array substrate, an auxiliary electrode, a light-emitting material layer, and a cathode. A bottom cut groove is provided between the auxiliary electrode and the array substrate, and the light-emitting material layer is filled in the bottom cut groove. The cathode is in surface contact with the auxiliary electrode. By filling the light-emitting material layer in the bottom cut groove, the exposed part of the auxiliary electrode contacts the cathode, increasing the contact area between the cathode and the auxiliary electrode, reducing the contact impedance of the cathode, and alleviating the technical problem of a large cathode voltage drop existing in the existing display panel.

Description

Technical Field

[0001] This application relates to the field of display technologies, and particularly to a display panel and a method for manufacturing a display panel. Background Art

[0002] The cathode of an existing display panel is usually made of a material with a relatively large resistivity, such as thin-layer metallic silver, which causes a large voltage drop, resulting in a significant difference between the actual driving voltage of the array substrate and the power supply voltage. In a large-size display panel, this manifests as uneven brightness over a large area, thus affecting the display effect.

[0003] Therefore, there is a technical problem of a large cathode voltage drop in existing display panels. Summary of the Invention

[0004] Embodiments of this application provide a display panel and a method for manufacturing a display panel, which can alleviate the technical problem of a large cathode voltage drop in existing display panels.

[0005] Embodiments of this application provide a display panel, including a surface cathode overlapping region, and the surface cathode overlapping region includes:

[0006] An array substrate;

[0007] An auxiliary electrode, which is disposed above the array substrate;

[0008] A light-emitting material layer, which is disposed above the array substrate;

[0009] A cathode, which is disposed above the light-emitting material layer and the auxiliary electrode, and the cathode overlaps with the auxiliary electrode;

[0010] Wherein, a passivation layer, a planarization layer, and a pixel definition layer are sequentially disposed above the array substrate. A via hole penetrating through the passivation layer, the planarization layer, and the pixel definition layer is provided in the surface cathode overlapping region. The auxiliary electrode is disposed in the via hole, and a bottom-cut groove is formed between the auxiliary electrode and the array substrate. The light-emitting material layer is filled in the bottom-cut groove.

[0011] Optionally, in some embodiments of this application, the surface of the auxiliary electrode away from the array substrate is convexly provided, and the convexity faces away from the array substrate.

[0012] Optionally, in some embodiments of this application, the auxiliary electrode includes a first electrode and a second electrode disposed on a side of the first electrode away from the array substrate. The first electrode and the array substrate form the bottom-cut groove, and the surface of the second electrode away from the array substrate is convexly provided, and the convexity faces away from the array substrate.

[0013] Optionally, in some embodiments of the present application, the first electrode includes a first portion and a second portion disposed on a side of the first portion away from the array substrate, and a positive projection of the first portion on the array substrate is smaller than a positive projection of the second portion on the array substrate.

[0014] Optionally, in some embodiments of the present application, the convex shape is a triangular pyramid shape, and a lower surface of the second electrode is in flush contact with an upper surface of the first electrode.

[0015] Optionally, in some embodiments of the present application, a vertex angle range of a side of the convex away from the array substrate is greater than or equal to 60 degrees, and a thickness range of the convex is greater than or equal to 110 nanometers.

[0016] Optionally, in some embodiments of the present application, the array substrate includes a substrate and a source electrode and a drain electrode located on one side of the substrate, the display panel further includes an anode connected to the source electrode, the first electrode is disposed in the same layer as the source electrode and the drain electrode, and the second electrode is disposed in the same layer as the anode.

[0017] Optionally, in some embodiments of the present application, the cathode covers the second electrode.

[0018] Optionally, in some embodiments of the present application, a lateral depth of the undercut groove is greater than 2 micrometers.

[0019] An embodiment of the present application provides a method for manufacturing a display panel, including:

[0020] Providing an array substrate;

[0021] Preparing an auxiliary electrode above the array substrate, and forming an undercut groove between the auxiliary electrode and the array substrate;

[0022] Sequentially preparing a passivation layer, a planarization layer, and a pixel definition layer above the array substrate;

[0023] Forming a via hole penetrating through the passivation layer, the planarization layer, and the pixel definition layer, and disposing the auxiliary electrode in the via hole;

[0024] Preparing a light-emitting material layer on a side of the pixel definition layer away from the array substrate, and in a surface cathode overlap region, filling the light-emitting material layer in the undercut groove.

[0025] Beneficial effects: An undercut groove is formed between the auxiliary electrode and the array substrate, and at the same time, the upper surface of the auxiliary electrode is convexly arranged, so that the light-emitting material layer is filled in the undercut groove, and part of the auxiliary electrode is exposed. The cathode is in surface contact with the auxiliary electrode. By increasing the contact area between the cathode and the auxiliary electrode, the contact impedance of the cathode is reduced, and the technical problem of large cathode voltage drop existing in the existing display panel is alleviated. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0027] Figure 1 is a cross-sectional schematic diagram of the display panel provided by the present application;

[0028] Figure 2A is a first cross-sectional schematic diagram of the method for manufacturing the display panel provided by the present application;

[0029] Figure 2B is a second cross-sectional schematic diagram of the method for manufacturing the display panel provided by the present application;

[0030] Figure 2C is a third cross-sectional schematic diagram of the method for manufacturing the display panel provided by the present application;

[0031] Figure 2D is a fourth cross-sectional schematic diagram of the method for manufacturing the display panel provided by the present application;

[0032] Figure 2E is a fifth cross-sectional schematic diagram of the method for manufacturing the display panel provided by the present application;

[0033] Figure 2F is a sixth cross-sectional schematic diagram of the method for manufacturing the display panel provided by the present application;

[0034] Figure 2G is a seventh cross-sectional schematic diagram of the method for manufacturing the display panel provided by the present application;

[0035] Figure 3 is a flowchart of the method for manufacturing the display panel provided by the present application.

[0036] Description of the Reference Numerals:

[0037] Detailed Embodiments

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the orientation words such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0039] In the existing display panel, the preparation material of the cathode usually has a large resistivity and a thin thickness, resulting in a large voltage drop in the display panel, making the display panel show large-area brightness non-uniformity, thus affecting the display effect; in order to reduce the cathode voltage drop, in the surface cathode overlapping region 1, the cathode is usually arranged to be in contact with the auxiliary electrode through a via hole that at least penetrates the light-emitting material layer, so as to reduce the resistance of the cathode. However, the cathode only contacts a part of the upper surface of the auxiliary electrode. Due to the small contact area, the contact impedance is large, and the effect of reducing the cathode resistance is not obvious, resulting in the technical problem that the cathode still has a large voltage drop.

[0040] Therefore, there is an urgent need in the prior art to provide a display panel that can reduce the cathode contact impedance in the surface cathode overlapping region 1.

[0041] Please refer to Figure 1 , the present application provides a display panel. In the surface cathode overlapping region 1, the display panel includes an array substrate 10, an auxiliary electrode, a light-emitting material layer 60, and a cathode 70. The auxiliary electrode is arranged above the array substrate 10, the light-emitting material layer 60 is arranged above the array substrate 70, the cathode 70 is arranged above the light-emitting material layer 60 and the auxiliary electrode, and the cathode 70 overlaps with the auxiliary electrode. Wherein, a passivation layer 102, a planarization layer 40, and a pixel definition layer 50 are sequentially arranged above the array substrate 10. A via hole penetrating the passivation layer 102, the planarization layer 40, and the pixel definition layer 50 is arranged in the surface cathode overlapping region 1. The auxiliary electrode is arranged in the via hole, and a bottom cut groove 2 is formed between the auxiliary electrode and the array substrate 10. The light-emitting material layer 60 is filled in the bottom cut groove 2.

[0042] In this embodiment, by filling the light-emitting material layer in the bottom cut groove, the exposed part of the auxiliary electrode contacts the cathode, increasing the contact area between the cathode and the auxiliary electrode, reducing the cathode contact impedance, and alleviating the technical problem that the existing display panel has a large cathode voltage drop.

[0043] Among them, the auxiliary electrode includes a first electrode 20 and a second electrode 30 disposed on a side of the first electrode 20 away from the array substrate 10.

[0044] Among them, the light-emitting material layer 60 is in the same layer as the light-emitting layer and is prepared through a single process. The display panel includes a light-emitting region and a surface cathode overlapping region 1, and the light-emitting layer is disposed in the light-emitting region.

[0045] Among them, the array substrate 10 further includes a passivation layer 102 disposed above the substrate 101. A via hole is provided in the passivation layer 102, and the first electrode 20 is located in the via hole.

[0046] It can be understood that the light-emitting material layer 60 is filled in the undercut groove 2, and the exposed first electrode 20 can be in surface contact with the cathode 70, so as to increase the contact area between the cathode 70 and the second electrode 30 and the first electrode 20, thereby reducing the contact impedance of the cathode 70, and further reducing the resistance of the cathode 70.

[0047] Now, the technical solution of the present application will be described in conjunction with specific embodiments.

[0048] In one embodiment, the surface of the auxiliary electrode away from the array substrate 10 is provided in a convex shape, and the convexity faces away from the array substrate 10.

[0049] In one embodiment, the first electrode 20 and the array substrate 10 form the undercut groove 2, and the surface of the second electrode 30 away from the array substrate 10 is provided in a convex shape, and the convexity faces away from the array substrate 10.

[0050] In one embodiment, the array substrate 10 includes a substrate 101 and a source electrode and a drain electrode on one side of the substrate. The display panel further includes an anode connected to the source electrode. The first electrode 20 is disposed in the same layer as the source electrode and the drain electrode, and the second electrode 30 is disposed in the same layer as the anode.

[0051] In one embodiment, no light-emitting material layer 60 is provided on the upper surface of the second electrode 30, and the cathode 70 is disposed to cover the second electrode 30.

[0052] It can be understood that the light-emitting material layer is filled in the undercut groove, so that part or all of the upper surface of the second electrode 30 can be exposed for contact with the cathode, so as to increase the contact area between the cathode and the auxiliary electrode, thereby reducing the contact impedance and further reducing the cathode voltage drop.

[0053] In this embodiment, a light-emitting material layer is not provided on the upper surface of the second electrode 30, that is, the upper surface is completely exposed to increase the contact area with the cathode 70. The design of completely exposing the upper surface of the second electrode 30 has a better effect on reducing the contact impedance of the cathode 70.

[0054] In one embodiment, the first part 201 and the second part 202 of the first electrode 20 are integrally provided.

[0055] Wherein, the array substrate 10 further includes a source-drain layer, the source-drain layer includes a source electrode and a drain electrode, and the first electrode 20 is on the same layer as the source / drain.

[0056] It can be understood that there is no need for an additional process to prepare the first electrode 20. When preparing the source / drain, the first electrode 20 is formed simultaneously.

[0057] In this embodiment, by arranging the first electrode 20 on the same layer as the existing film layer, the manufacturing process is simplified and the cost is reduced.

[0058] In one embodiment, the upper surface of the second electrode 30 is convexly arranged, and the convexity faces away from the substrate 101.

[0059] Wherein, the convex shape can be any one of a trapezoidal shape, a conical shape, and a triangular shape.

[0060] It can be understood that the organic material is guided into the undercut groove 2 by the convexity. The upper surface of the convex shape is beneficial to filling the light-emitting material layer 60 in the undercut groove 2, preventing the light-emitting material from being disposed on the surfaces of the first electrode 20 and the second electrode 30, increasing the contact area between the cathode 70 and the second electrode 30 and the first electrode 20, thereby reducing the contact impedance between the cathode 70 and the second electrode 30 and the first electrode 20.

[0061] It can be understood that at least one inclined surface is required on the upper surface of the second electrode 30, and the inclined surface is used to guide the organic material into the undercut groove 2.

[0062] It should be noted that the convexity on the upper surface of the second electrode 30 can also increase the contact area between the upper surface of the second electrode 30 and the cathode 70.

[0063] In this embodiment, by arranging the upper surface of the second electrode 30 to be convex, it is beneficial for the light-emitting material of the light-emitting material layer 60 to enter the undercut groove 2, and part of the first electrode 20 is exposed to reduce the contact impedance of the cathode 70.

[0064] In one embodiment, the contact area between the cathode 70 and the second electrode 30 and the first electrode 20 is larger than the upper surface area of the second electrode 30.

[0065] Wherein, a light-emitting material layer may not be provided on the side surface of the cathode 70 away from the array substrate 10, that is, the side of the cathode away from the array substrate is completely exposed. At the same time, the cathode also contacts the side portion of the auxiliary electrode.

[0066] In this embodiment, the contact area between the cathode 70 and the auxiliary electrode is further defined to reduce the cathode impedance and the voltage drop of the cathode 70.

[0067] In one embodiment, the cathode 70 only contacts the second electrode 30, and a convex structure is provided on the upper surface of the second electrode 30, and the convex structure is an independent member.

[0068] Wherein, the cathode 70 contacts the side surface of the second electrode 30.

[0069] Wherein, the material for preparing the convex structure is a conductive material, and the material for preparing the convex structure may be different from that of the second electrode 30.

[0070] Wherein, the convex structure may be the same as the second electrode 30.

[0071] In this embodiment, by further providing an independent member on the surface of the second electrode 30, the independent member is a convex, thereby reducing the contact impedance of the cathode 70.

[0072] In one embodiment, the convex shape is a triangular pyramid shape, and the lower surface of the second electrode 30 is flush with the upper surface of the second part 202.

[0073] In one embodiment, the apex angle range of the convex is greater than or equal to 60 degrees, and the thickness range of the convex is greater than or equal to 110 nanometers.

[0074] Wherein, the apex angle is the angle of the convex away from the array substrate.

[0075] In one embodiment, a pixel definition layer 50 and a planarization layer 40 are further provided above the array substrate 10, and the orthographic projections of the pixel definition layer 50 and the planarization layer 40 on the substrate 101 are misaligned with the orthographic projection of the undercut groove 2 on the substrate 101.

[0076] Wherein, the thickness of the pixel definition layer 50 may be 2000 angstroms.

[0077] It can be understood that the flat layer 40 and the pixel definition layer 50 in the undercut groove 2 are removed, so that only the light-emitting material layer 60 is accommodated in the undercut groove 2.

[0078] In one embodiment, the preparation materials of the pixel definition layer 50 and the flat layer 40 are positive photoresist materials.

[0079] In one embodiment, the preparation materials of the pixel definition layer 50 and the flat layer 40 are the same.

[0080] Among them, the flat layer 40 is a preparation material with strong leveling property.

[0081] In this embodiment, the flat layer 40 has strong leveling property, which is beneficial to the flat layer 40 filling the undercut groove 2.

[0082] In one embodiment, the cathode 70 is also partially disposed in the undercut groove 2, and the part of the cathode 70 located in the undercut groove 2 can be in contact with the side surface of the first part 201.

[0083] In this embodiment, the cathode located in the undercut groove is also in contact with the side surface of the first electrode, further increasing the contact area and reducing the contact impedance.

[0084] In one embodiment, the preparation materials of the second electrode 30 and the cathode 70 are any one of indium tin oxide, indium zinc oxide, molybdenum titanium, and titanium.

[0085] Among them, the preparation materials of the second electrode 30 and the cathode 70 can be the same.

[0086] In one embodiment, the lateral depth of the undercut groove 2 is greater than 2 microns.

[0087] Among them, the width of the second part 202 is at least 4 microns larger than that of the first part 201.

[0088] It can be understood that when preparing the light-emitting layer in the existing display panel, the light-emitting material layer 60 is easily prepared synchronously in the surface cathode overlapping area 1, and the light-emitting material layer 60 will cover the sides of the first electrode 20 and the second electrode 30, resulting in a small contact area and a large contact impedance between the cathode 70 and the second electrode 30.

[0089] In this embodiment, by defining the lateral depth of the undercut groove 2, it is ensured that there is enough accommodation space in the undercut groove 2 to fill the light-emitting material layer 60.

[0090] Please refer to Figures 2A to 2G 、 Figure 3 , the embodiment of the present application provides a method for manufacturing a display panel, including:

[0091] S1: Provide an array substrate 10;

[0092] S2: Prepare an auxiliary electrode above the array substrate 10, and form an undercut groove 2 between the auxiliary electrode and the array substrate 10;

[0093] S3: Sequentially prepare a passivation layer 102, a planarization layer 40, and a pixel definition layer 50 above the array substrate 10;

[0094] S4: Form a via hole penetrating through the passivation layer 102, the planarization layer 40, and the pixel definition layer 50, and place the auxiliary electrode inside the via hole;

[0095] S5: Prepare a light-emitting material layer 60 on the side of the pixel definition layer 50 away from the array substrate 10. In the cathode overlap region 1, the light-emitting material layer 60 fills the undercut groove 2.

[0096] Wherein, the contact area between the cathode 70 and the auxiliary electrode is larger than the upper surface area of the auxiliary electrode.

[0097] Furthermore, the contact area between the cathode 70 and the second electrode 30, the first electrode 20 is larger than the upper surface area of the second electrode 30.

[0098] Wherein, please refer to Figure 2A , provide an array substrate 10, and the array substrate 10 includes a first electrode 20;

[0099] Wherein, please refer to Figure 2B , prepare a first part 201, a second part 202, and an undercut groove 2 of the first electrode 20;

[0100] Wherein, please refer to Figure 2C , coat a first organic material with relatively strong fluidity to fill the undercut groove 2;

[0101] Wherein, please refer to Figure 2D , prepare the second electrode 30, and the upper surface of the second electrode 30 can be conical;

[0102] Wherein, please refer to Figure 2E , coat a second organic material, expose and remove the first organic material and the second organic material above the undercut groove 2, and prepare a planarization layer 40 and a pixel definition layer 50;

[0103] Wherein, please refer to Figure 2F , prepare the light-emitting material layer 60, and the undercut groove 2 is filled with the light-emitting material layer 60;

[0104] Wherein, please refer toFigure 2G , the cathode 70 is prepared, and the cathode 70 is in surface contact with both the second electrode 30 and the first electrode 20.

[0105] In one embodiment, the pixel definition layer 50 can be fabricated by exposing a half-tone mask.

[0106] In one embodiment, the steps of preparing the first part 201 and the second part 202 disposed on the first part 201 further include: by means of a photolithography process, etching the first electrode 20 layer to prepare an undercut groove 2, the second part 202 covers the first part 201, and the depth of the undercut groove 2 is greater than 2 microns.

[0107] In one embodiment, the steps of preparing the planarization layer 40 and the pixel definition layer 50 further include: the first organic material is the same as the second organic material, and the planarization layer 40 and the pixel definition layer 50 are prepared by exposing the first organic material and the second organic material in one process.

[0108] In this embodiment, by preparing the planarization layer 40 and the pixel definition layer 50 in one process, the process is simplified and the cost is reduced.

[0109] In one embodiment, the steps of preparing the second electrode 30 further include: depositing a layer of conductive material, patterning the conductive material to form the upper surface of the second electrode 30 in a triangular pyramid shape, and the lower surface of the second electrode 30 is flush with the upper surface of the second part 202.

[0110] The present application also provides a display module and a display device, wherein both the display module and the display device include the above-mentioned display panel, which will not be elaborated here.

[0111] The display panel provided in this embodiment includes a surface cathode overlapping region, the surface cathode overlapping region includes an array substrate, an auxiliary electrode, a light-emitting material layer, and a cathode, an undercut groove is formed between the auxiliary electrode and the array substrate, and the light-emitting material layer is filled in the undercut groove; by forming an undercut groove between the auxiliary electrode and the array substrate, the light-emitting material layer is filled in the undercut groove, and the exposed auxiliary electrode contacts the cathode, increasing the contact area between the cathode and the auxiliary electrode, reducing the contact impedance of the cathode, and thus reducing the cathode voltage drop.

[0112] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0113] The above has introduced in detail a display panel and a method for manufacturing a display panel provided by the embodiments of the present application. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A display panel includes a surface cathode overlapping region, characterized in that, The surface cathode overlapping region includes: An array substrate; An auxiliary electrode disposed above the array substrate; A light-emitting material layer disposed above the array substrate; A cathode disposed above the light-emitting material layer and the auxiliary electrode, and the cathode overlaps with the auxiliary electrode; Wherein, a passivation layer, a planarization layer, and a pixel definition layer are sequentially disposed above the array substrate. A via hole penetrating through the passivation layer, the planarization layer, and the pixel definition layer is provided in the surface cathode overlapping region. The auxiliary electrode is disposed in the via hole, and an undercut groove is formed between the auxiliary electrode and the array substrate. The light-emitting material layer is filled in the undercut groove. The auxiliary electrode includes a first electrode and a second electrode disposed on a side of the first electrode away from the array substrate. The first electrode and the array substrate form the undercut groove. The first electrode includes a first portion and a second portion disposed on a side of the first portion away from the array substrate. A positive projection of the first portion on the array substrate is smaller than a positive projection of the second portion on the array substrate. A surface of the second electrode away from the array substrate protrudes, and the protrusion faces away from the array substrate to form at least one inclined surface for guiding an organic material into the undercut groove.

2. The display panel according to claim 1, characterized in that, The protrusion is in a triangular pyramid shape, and a lower surface of the second electrode is in flush contact with an upper surface of the first electrode.

3. The display panel according to claim 2, characterized in that, An apex angle range of a side of the protrusion away from the array substrate is greater than or equal to 60 degrees, and a thickness range of the protrusion is greater than or equal to 110 nanometers.

4. The display panel according to claim 1, wherein The array substrate includes a substrate and a source electrode and a drain electrode located on one side of the substrate. The display panel further includes an anode connected to the source electrode. The first electrode is disposed in the same layer as the source electrode and the drain electrode, and the second electrode is disposed in the same layer as the anode.

5. The display panel according to claim 1, wherein The cathode covers the second electrode.

6. The display panel according to claim 1, wherein A lateral depth of the undercut groove is greater than 2 micrometers.

7. A method for manufacturing a display panel, which is used to manufacture the display panel according to any one of claims 1 to 6, characterized in that, Including: Providing an array substrate; Preparing an auxiliary electrode above the array substrate, and forming an undercut groove between the auxiliary electrode and the array substrate; Sequentially preparing a passivation layer, a planarization layer, and a pixel definition layer above the array substrate; Forming a via hole penetrating through the passivation layer, the planarization layer, and the pixel definition layer to make the auxiliary electrode located in the via hole; Preparing a light-emitting material layer on a side of the pixel definition layer away from the array substrate, and in the surface cathode overlapping region, the light-emitting material layer is filled in the undercut groove.

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