Display panel and preparation method thereof

Abstract

The embodiment of the invention discloses a display panel and a preparation method thereof, a second electrode is formed on a first electrode, and the second electrode covers an abnormal bulge and the first electrode. According to the display panel and the preparation method thereof, the second electrode is adopted to cover and flatten the abnormal protrusions formed on the first electrode, so that the light-emitting material layer of the light-emitting functional layer can cover the second electrode on the whole surface, the short circuit path of the first electrode and the third electrode is cut off, and short circuit of the first electrode and the third electrode is avoided.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display panel. Background Art

[0002] One of the factors that has the greatest impact on the yield of OLED products is the large number of dark spots, which makes it difficult to meet customer specifications. The reason for the high incidence of dark spots is mostly related to tiny foreign matter on the anode of OLED devices, metal material precipitation protrusions, and micro-residues of the pixel definition layer. The current mainstream approach is to use technical means such as aging tests to identify and eliminate dark spots, but the essence of this solution is to reduce the impact range of dark spots to make them difficult for the human eye to identify at a long distance, and it does not completely eliminate dark spots from the root.

[0003] In the process of research and practice of the prior art, the inventors of this application found that the types of dark spots mainly include the following three types: type one dark spot is caused by the bulge caused by the precipitation of metal on the anode, which causes the cathode and the anode to short-circuit and produce dark spots; type two dark spot is caused by foreign matter under the anode causing the anode film to bulge, which causes the cathode and the anode to short-circuit and produce dark spots; type three dark spot is caused by the material residue or micro-residue of the pixel definition layer, which causes the uneven spreading of the ink in the organic light-emitting layer, causing the cathode and the anode to short-circuit and produce dark spots. Summary of the invention

[0004] The embodiments of the present application provide a display panel and a method for manufacturing the same, which can improve the effect of poor dark spots.

[0005] The present invention provides a method for manufacturing a display panel, which comprises the following steps:

[0006] A driving substrate is provided, the driving substrate comprising an abnormal protrusion, a flat layer, a first electrode and a pixel definition layer, the first electrode is arranged on the flat layer, the pixel definition layer is arranged on the first electrode, a plurality of openings are opened on the pixel definition layer, one of the openings correspondingly exposes one of the first electrodes, at least some of the plurality of openings have the abnormal protrusion in them, and the abnormal protrusion is formed on a side of the first electrode away from the flat layer;

[0007] forming a second electrode on the driving substrate, wherein the second electrode is disposed in the opening and covers the abnormal protrusion and the first electrode;

[0008] A light-emitting functional layer and a third electrode are sequentially formed on the driving substrate, wherein the light-emitting functional layer at least includes a light-emitting material layer, the light-emitting material layer continuously and entirely covers the second electrode, and the third electrode covers the light-emitting functional layer.

[0009] Optionally, in some embodiments of the present application, the second electrode includes a first part and a second part connected to the first part, the first part covers the abnormal protrusion, the second part covers and is connected to the first electrode, and there is a first distance from the side of the first part away from the first electrode to the surface of the second part away from the first electrode, and the first distance is greater than or equal to 0 microns; the distance from the surface of the light-emitting material layer stacked with the second part away from the first electrode to the surface of the second part away from the first electrode is a second distance, and the first distance is less than or equal to half of the second distance.

[0010] Optionally, in some embodiments of the present application, forming a second electrode on the driving substrate includes the following steps:

[0011] forming an electrode material layer on the driving substrate, wherein the electrode material layer entirely covers the driving substrate;

[0012] The electrode material layer is patterned to form a plurality of second electrodes, each of the openings is provided with a corresponding second electrode, in the opening with an abnormal protrusion, the second electrode covers the abnormal protrusion and the first electrode, and in the opening without the abnormal protrusion, the second electrode covers the first electrode.

[0013] Optionally, in some embodiments of the present application, the thickness of the second electrode is greater than the thickness of the first electrode.

[0014] Optionally, in some embodiments of the present application, the thickness of the second electrode is greater than or equal to twice the thickness of the first electrode.

[0015] Optionally, in some embodiments of the present application, before forming the second electrode on the driving substrate, the following steps are further included:

[0016] Acquire a first real-time image in the opening area, identify the abnormal protrusion and acquire characteristic information of the abnormal protrusion based on the comparison between the first real-time image and the standard image, wherein the characteristic information includes the protrusion height;

[0017] If the protrusion height of the abnormal protrusion is less than or equal to half of the thickness of the first electrode, the step of forming a second electrode on the driving substrate is performed.

[0018] Optionally, in some embodiments of the present application, the characteristic information of the abnormal protrusion also includes position information and contour information; after forming the second electrode on the driving substrate and before sequentially forming the light-emitting functional layer and the third electrode on the driving substrate, the following steps are also included:

[0019] Acquire a second real-time image in the opening area, and determine whether a protruding height of the first portion of the second electrode is greater than half of the second distance based on a comparison between the second real-time image and a standard image;

[0020] If yes, then according to the position information and the contour information, removing the abnormal protrusion to form a hole, the depth of the hole being greater than or equal to the sum of the thicknesses of the first electrode and the second electrode;

[0021] The excavated hole is filled with a patching material.

[0022] Optionally, in some embodiments of the present application, filling the excavated hole with a repair material comprises the following steps:

[0023] Acquire film layer information of the second electrode, wherein the film layer information includes the number of film layers, material information of each film layer, and thickness information of each film layer;

[0024] If the number of the film layers is one, the same material as the second electrode is selected as the repair material to fill the hole;

[0025] If the number of film layers is at least two, the same material as the thickest film layer in the second electrode is selected as the repair material to fill the hole, or, according to the order of the film layers, the same material as the corresponding film layers in the second electrode is selected in sequence as the repair material to repair the hole.

[0026] Optionally, in some embodiments of the present application, removing the abnormal protrusion to form a hole further includes the following steps:

[0027] According to the position information and the contour information of the abnormal protrusion, the contour line information of the hole is obtained and a first contour line trajectory of the hole is generated, wherein the first contour line of the hole is formed by extending the contour line of the abnormal protrusion outward by a set distance, and the set distance is between 0.4 micrometers and 1 micrometer;

[0028] determining whether the first contour line trajectory is within the inner contour of the opening;

[0029] If the first contour line track is within the inner contour of the opening, then according to the first contour line track, the abnormal protrusion is removed to form the excavated hole;

[0030] If part of the first contour line trajectory exceeds the inner contour of the opening, the part of the first contour line trajectory exceeding the inner contour of the opening is removed to generate a second contour line trajectory, and the abnormal protrusion is removed according to the second contour line trajectory to form the hole.

[0031] Accordingly, an embodiment of the present application further provides a display panel, which includes:

[0032] A driving substrate, the driving substrate comprising an abnormal protrusion, a flat layer, a first electrode and a pixel definition layer, the first electrode is arranged on the flat layer, the pixel definition layer is arranged on the first electrode, a plurality of openings are opened on the pixel definition layer, one of the openings correspondingly exposes one of the first electrodes, at least some of the plurality of openings have the abnormal protrusion in them, and the abnormal protrusion is formed on a side of the first electrode away from the flat layer;

[0033] a second electrode, in the opening having the abnormal protrusion, the second electrode being disposed in the opening and covering the abnormal protrusion and the first electrode;

[0034] a light-emitting functional layer, covering the second electrode, the light-emitting functional layer at least comprising a light-emitting material layer, the light-emitting material layer continuously and entirely covers the second electrode; and

[0035] The third electrode covers the light-emitting functional layer.

[0036] Optionally, in some embodiments of the present application, the second electrode includes a first portion and a second portion connected to the first portion, the first portion covers the abnormal protrusion, the second portion covers and is connected to the first electrode, and a first distance exists between a side of the first portion away from the first electrode and a surface of the second portion away from the first electrode, and the first distance is greater than or equal to 0 micrometers;

[0037] A distance from a surface of the light-emitting material layer stacked with the second portion away from the first electrode to a surface of the second portion away from the first electrode is a second distance, and the first distance is less than or equal to half of the second distance.

[0038] Optionally, in some embodiments of the present application, the thickness of the second electrode is greater than the thickness of the first electrode.

[0039] Optionally, in some embodiments of the present application, a hole is formed on the electrode structure formed by stacking the first electrode and the second electrode, and the depth of the hole is greater than or equal to the thickness of the electrode structure;

[0040] The excavated hole is filled with a repair material, and the repair material is at least partially the same as the material of the electrode structure.

[0041] The display panel and its preparation method in the embodiment of the present application are covered with a second electrode and flattened with an abnormal protrusion, so that the luminescent material layer of the luminescent functional layer can cover the second electrode in its entirety, cutting off the short-circuit path between the first electrode and the third electrode, thereby avoiding short-circuit between the first electrode and the third electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic diagram of the structure of a display panel provided in an embodiment of the present application;

[0043] Figure 2 is another structural schematic diagram of a display panel provided in an embodiment of the present application;

[0044] Figure 3 is a schematic diagram of a process for preparing a display panel provided in an embodiment of the present application;

[0045] Figure 4 is a schematic diagram of step B1 of the method for preparing a display panel provided in an embodiment of the present application;

[0046] Figure 5 is a schematic diagram of step B21 of the method for preparing a display panel provided in an embodiment of the present application;

[0047] Figure 6 is a schematic diagram of step B22 of the method for preparing a display panel provided in an embodiment of the present application;

[0048] Figure 7 is a schematic diagram of step B3 of the method for preparing a display panel provided in an embodiment of the present application;

[0049] Figure 8 is a schematic diagram of step B4a of the method for preparing a display panel provided in an embodiment of the present application;

[0050] Fig. 9 is a schematic diagram of step B4b of the method for preparing a display panel provided in an embodiment of the present application;

[0051] Fig.10 is a schematic diagram of step B4d of the method for preparing a display panel provided in an embodiment of the present application;

[0052] Fig.11 It is a schematic diagram of step B4f of the method for preparing a display panel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods 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, the various embodiments can be combined with each other but will not be repeated one by one, and in the absence of contrary instructions, the directional words used, such as "upper" and "lower", usually refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the drawings; while "inside" and "outside" refer to the outline of the device; the terms "first", "second", "third", etc. are used only as markings, and no numerical requirements are imposed or order is established.

[0054] The embodiments of the present application provide a display panel and a method for manufacturing the same, which are described in detail below. It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments.

[0055] Please refer to Figure 1 , Figure 1 FIG. 1 is a schematic diagram showing the structure of a display panel 100 according to an embodiment of the present application.

[0056] The embodiment of the present application further provides a display panel 100 , which includes a driving substrate 11 , a second electrode 12 , a light-emitting functional layer 13 and a third electrode 14 .

[0057] The driving substrate 11 includes an abnormal protrusion 111, a flat layer 112, a first electrode 113 and a pixel definition layer 114. The first electrode 113 is disposed on the flat layer 112. The pixel definition layer 114 is disposed on the first electrode 113. A plurality of openings 11a are provided on the pixel definition layer 114, and one opening 11a correspondingly exposes one first electrode 113. At least some of the openings 11a among the plurality of openings 11a have an abnormal protrusion 111, and the abnormal protrusion 111 is formed on a side of the first electrode 113 away from the flat layer 112.

[0058] In the opening 11a having the abnormal protrusion 111, the second electrode 12 is arranged in the opening 11a and covers the abnormal protrusion 111 and the first electrode 113. The light-emitting functional layer 13 covers the second electrode 12. The light-emitting functional layer 13 includes at least a light-emitting material layer 131, and the light-emitting material layer 131 continuously covers the entire surface of the second electrode 12. The third electrode 14 covers the light-emitting functional layer 13.

[0059] In the opening 11 a without the abnormal protrusion 111 , the second electrode 12 covers the first electrode 113 .

[0060] It can be understood that the abnormal protrusions 111 include two types. The first type of abnormal protrusions 111 are formed on the upper surface of the first electrode 113; the second type of abnormal protrusions 111 are protrusions formed when abnormal particles are arranged on the lower surface of the first electrode 113 so that the first electrode 113 covers the abnormal particles. Figure 1 In the description, the abnormal protrusion 111 is taken as an example of the first type of abnormal protrusion, but is not limited to this.

[0061] The display panel 100 of the embodiment of the present application uses the second electrode 12 to cover and flatten the abnormal protrusion 111, so that the light-emitting material layer 131 of the light-emitting functional layer 13 can cover the second electrode 12 on the entire surface, blocking the short-circuit path between the first electrode 113 and the third electrode 14, thereby avoiding short-circuiting between the first electrode 113 and the third electrode 14.

[0062] The second electrode 12 can be formed by vapor deposition, evaporation or inkjet printing. In the process of forming the second electrode 12, the abnormal protrusion 111 is flattened by adjusting the process, for example, the physical sputtering process can use a magnetic field or an electric field to adjust the sputtering direction of the material, or the evaporation process can adjust the evaporation angle, or the inkjet printing process can use the leveling property of the ink material to flatten the abnormal protrusion 111.

[0063] Secondly, the light emitting material layer 131 covers the entire surface of the second electrode 12 , so that the light emitting material layer 131 physically separates the electrical connection path between the second electrode 12 and the third electrode 14 , thereby preventing the first electrode 113 and the third electrode 14 from being short-circuited.

[0064] Optionally, the light-emitting material layer 131 can be formed by evaporation or inkjet printing. It should be noted that when the second electrode 12 flattens the abnormal protrusion 111, if there are still tiny protrusions in the area of ​​the second electrode 12 corresponding to the abnormal protrusion 111, the light-emitting material layer 131 is formed by inkjet printing, and the leveling property of the material can be used to ensure that the light-emitting material layer 131 continuously covers the entire surface of the second electrode 12; or the angle of evaporation can be adjusted to ensure that the light-emitting material layer 131 continuously covers the entire surface of the second electrode 12.

[0065] Optionally, the light-emitting material layer 131 may be an organic material, such as Alq3, bis(2-methyl-8-hydroxyquinoline-N1,08)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq), DPVBi, Almq3, 3-tert-butyl-9,10-di(2-naphthalene)anthracene (TBADN). The material of the light-emitting material layer 131 may also be an inorganic material, such as one or more selected from group IV semiconductor nanocrystals, group II-V semiconductor nanocrystals, group II-VI semiconductor nanocrystals, group IV-VI semiconductor nanocrystals, group III-V semiconductor nanocrystals, and group III-VI semiconductor nanocrystals. As an example, it may be one or more of silicon quantum dots, germanium quantum dots, cadmium sulfide quantum dots, cadmium selenide quantum dots, cadmium telluride quantum dots, zinc selenide quantum dots, lead sulfide quantum dots, lead selenide quantum dots, indium phosphide quantum dots, indium arsenide quantum dots, and gallium nitride quantum dots.

[0066] Optionally, the first electrode 113 and the second electrode 12 are stacked to form an electrode structure, and one of the electrode structure and the third electrode 14 is an anode, and the other is a cathode. Figure 1 In the embodiment of the present application, the electrode structure is an anode and the third electrode 14 is a cathode.

[0067] Optionally, the first electrode 113 and the second electrode 12 may each be a single film layer or a stack of multiple film layers. The material of the second electrode 12 and the first electrode 113 may each be selected from at least one of ITO, IZO and Ag.

[0068] Optionally, the material of the second electrode 12 is the same as that of the first electrode 113. The third electrode 14 is a transparent conductive material, such as a metal oxide, such as ITO, IZO, and the like.

[0069] Optionally, the driving substrate 11 further includes a thin film transistor structure layer.

[0070] Optionally, the light-emitting functional layer 13 may further include a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer. The hole injection layer and the hole transport layer are arranged on the side of the light-emitting material layer 131 close to the second electrode 12, and the hole transport layer and the electron transport layer are arranged on the side of the light-emitting material layer 131 close to the third electrode 14.

[0071] It should be noted that the hole injection layer and the hole transport layer can also be formed by inkjet printing or evaporation, wherein the inkjet printing process can relatively simply flatten the weak protrusions left after the second electrode 12 covers the abnormal protrusions 111, providing a flat foundation for the light-emitting material layer 131. That is, at least one of the hole injection layer and the hole transport layer completely flattens the abnormal protrusions 111.

[0072] In some embodiments of the present application, in the opening 11a having the abnormal protrusion 111, the second electrode 12 includes a first portion 121 and a second portion 122 connected to the first portion 121, the first portion 121 covers the abnormal protrusion 111, and the second portion 122 covers and is connected to the first electrode 113. There is a first distance h1 from the side of the first portion 121 away from the first electrode 113 to the surface of the second portion 122 away from the first electrode 113, and the first distance h1 is greater than or equal to 0 micrometers.

[0073] A distance from a surface of the light emitting material layer 131 stacked with the second portion 122 away from the first electrode 113 to a surface of the second portion 122 away from the first electrode 113 is a second distance h2, and the first distance h1 is less than or equal to half of the second distance h2.

[0074] It should be understood that if the first distance h1 is equal to 0 micrometer, it means that the second electrode 12 completely flattens the abnormal protrusion 111; if the first distance h1 is greater than 0 micrometer, it means that after the second electrode 12 flattens the abnormal protrusion 111, the area covered by the second electrode 12 on the abnormal protrusion 111 still has a weak protrusion. Figure 1 In the figure, the first distance h1 is equal to 0 micrometers as an example, that is, the first part 121 and the second part 122 are flush.

[0075] In addition, based on the product specifications, the first electrode 113, the second electrode 12, the light-emitting material layer 131, the hole transport layer and the hole injection layer all have thickness specification requirements, resulting in the thickness of the light-emitting material layer 131, the hole transport layer and the hole injection layer cannot be increased arbitrarily. Therefore, the first distance h1 is less than or equal to half of the second distance h2, so that the light-emitting material layer 131 can continuously cover the second electrode 12 on the entire surface to separate the short-circuit path between the first electrode 113 and the third electrode 14.

[0076] For example, the first distance h1 may be 0 micrometer, 0.11 micrometer, 0.12 micrometer, 0.13 micrometer, 0.14 micrometer, 0.15 micrometer, 0.16 micrometer, 0.17 micrometer or 0.18 micrometer.

[0077] In some embodiments of the present application, the thickness of the second electrode 12 is greater than the thickness of the first electrode 113 .

[0078] It is understandable that the greater the thickness of the second electrode 12 , the better the effect of leveling the abnormal protrusion 111 . Therefore, the thickness of the second electrode 12 is greater than that of the first electrode 113 to better level the abnormal protrusion 111 .

[0079] Optionally, the thickness of the second electrode 12 is greater than or equal to twice the thickness of the first electrode 113 .

[0080] Please refer to Figure 2, Figure 2 Another structural schematic diagram of the display panel 100 according to an embodiment of the present application is shown. Figure 2 The embodiment shown is in Figure 1 On the basis of the corresponding embodiment, an embodiment of further removing the large-sized abnormal protrusions is provided, which avoids the short circuit between the first electrode and the third electrode by removing the large-sized abnormal protrusions and repairing the holes.

[0081] It is understandable that the distribution of the abnormal protrusions 111 depends on the actual situation. For example, the large-sized abnormal protrusions 111 and the small-sized abnormal protrusions 111 can be in the same opening 11a, or the large-sized abnormal protrusions can be alone in the opening 11a. Figure 2 In the embodiment, the large-sized abnormal protrusion and the small-sized abnormal protrusion 111 can be repaired in the same opening 11a, but the present invention is not limited thereto.

[0082] exist Figure 2 In some embodiments of the present application, a hole 12a is formed on the electrode structure formed by stacking the first electrode 113 and the second electrode 12, and the depth of the hole 12a is greater than or equal to the thickness of the electrode structure.

[0083] The hole 12a is filled with a repair material 15, and the repair material 15 is at least partially the same as the material of the electrode structure.

[0084] It should be noted that when the abnormal protrusions 111 have large-sized abnormal protrusions, the second electrode 12 cannot well flatten the large-sized abnormal protrusions 111, so that the area of ​​the abnormal protrusions 111 still has the risk of short-circuiting the third electrode 14 and the first electrode 113. In order to reduce or even avoid this risk, the large-sized abnormal protrusions 111 can be removed by digging holes and repairing the holes.

[0085] Please refer to Figure 3 Accordingly, an embodiment of the present application provides a method for preparing a display panel, which includes the following steps:

[0086] Step B1, providing a driving substrate, the driving substrate comprising an abnormal protrusion, a flat layer, a first electrode and a pixel definition layer, the first electrode is arranged on the flat layer, the pixel definition layer is arranged on the first electrode, a plurality of openings are opened on the pixel definition layer, one of the openings correspondingly exposes one of the first electrodes, at least some of the plurality of openings have the abnormal protrusion in them, and the abnormal protrusion is formed on a side of the first electrode away from the flat layer;

[0087] Step B2, forming a second electrode on the driving substrate, wherein the second electrode is disposed in the opening and covers the abnormal protrusion and the first electrode;

[0088] Step B3, sequentially forming a light-emitting functional layer and a third electrode on the driving substrate, wherein the light-emitting functional layer at least includes a light-emitting material layer, the light-emitting material layer continuously and entirely covers the second electrode, and the third electrode covers the light-emitting functional layer.

[0089] It can be understood that the method for preparing the display panel of the embodiment of the present application is used to prepare the display panel 100 of any one of the above embodiments.

[0090] The preparation method of the display panel 100 of the embodiment of the present application uses the second electrode 12 to cover and flatten the abnormal protrusion 111, so that the light-emitting material layer 131 of the light-emitting functional layer 13 can cover the second electrode 12 on the entire surface, blocking the short-circuit path between the first electrode 113 and the third electrode 14, thereby avoiding the short-circuit between the first electrode 113 and the third electrode 14.

[0091] The following will describe in detail the method for manufacturing the display panel 100 .

[0092] Please refer to Figure 4 , step B1, providing a driving substrate 11. The driving substrate 11 includes an abnormal protrusion 111, a flat layer 112, a first electrode 113 and a pixel definition layer 114. The first electrode 113 is disposed on the flat layer 112, the pixel definition layer 114 is disposed on the first electrode 113, a plurality of openings 11a are provided on the pixel definition layer 114, one opening 11a correspondingly exposes one first electrode 113, at least some of the openings 11a among the plurality of openings 11a have an abnormal protrusion 111, and the abnormal protrusion 111 is formed on a side of the first electrode 113 away from the flat layer 112.

[0093] It is understandable that the sizes of the abnormal protrusions 111 are different. In the actual manufacturing process, abnormal protrusions 111 of different sizes can be arranged in one opening 11a at the same time, or in different openings 11a respectively. Of course, there are also some openings 11a without abnormal protrusions 111.

[0094] Optionally, if the height of the abnormal protrusion 111 is less than or equal to half the thickness of the first electrode 113 , it is a small-sized abnormal protrusion 111 , otherwise it is a large-sized abnormal protrusion 111 .

[0095] Then proceed to step B2.

[0096] Step B2: forming a second electrode 12 on the driving substrate 11 . The second electrode 12 is disposed in the opening 11 a and covers the abnormal protrusion 111 and the first electrode 113 .

[0097] Wherein, step B2 comprises the following steps:

[0098] Please refer to Figure 5, step B21, forming an electrode material layer 12c on the driving substrate 11. The electrode material layer 12c covers the entire surface of the driving substrate 11.

[0099] The electrode material layer 12c may be formed by evaporation or physical sputtering. The electrode material layer 12c may be a single film layer or a multi-layer stacked structure.

[0100] Optionally, the material of the electrode material layer 12 c may be selected from at least one of ITO, IZO and Ag. In some embodiments, the material of the electrode material layer 12 c is consistent with the material of the first electrode 113 .

[0101] Then proceed to step B22.

[0102] Please refer to Figure 6 Step B22: patterning the electrode material layer 12c to form a plurality of second electrodes 12. Each opening 11a is provided with a second electrode 12. In the opening 11a with the abnormal protrusion, the second electrode 12 covers the abnormal protrusion 111 and the first electrode 113. In the opening 11a without the abnormal protrusion 111, the second electrode 12 covers the first electrode 113.

[0103] The second electrode 12 may be formed by exposure, development and etching.

[0104] In some embodiments, the second electrode 12 may also be formed by inkjet printing.

[0105] It should be noted that the size of the abnormal protrusion 111 varies, and no matter whether the abnormal protrusion 111 is large or small, it can be flattened by the second electrode 12. The preparation method can also be that the small-sized abnormal protrusion 111 is flattened by the second electrode 12; the large-sized abnormal protrusion 111 can be flattened by removing and repairing the small-sized abnormal protrusion 111.

[0106] In some embodiments of the present application, it can be understood that the greater the thickness of the second electrode 12 , the better the effect of leveling the abnormal protrusion 111 , so the thickness of the second electrode 12 is greater than the thickness of the first electrode 113 so that the second electrode 12 can better level the abnormal protrusion 111 .

[0107] Optionally, the thickness of the second electrode 12 is greater than or equal to twice the thickness of the first electrode 113 , so that the second electrode 12 can better flatten the abnormal protrusion 111 .

[0108] In some embodiments of the present application, the second electrode 12 includes a first portion 121 and a second portion 122 connected to the first portion 121. The first portion 121 covers the abnormal protrusion 111, and the second portion 122 covers and is connected to the first electrode 113. There is a first distance h1 from the side of the first portion 121 away from the first electrode 113 to the surface of the second portion 122 away from the first electrode 113, and the first distance h1 is greater than or equal to 0 micrometers.

[0109] It should be understood that if the first distance h1 is equal to 0 micrometer, it means that the second electrode 12 completely flattens the abnormal protrusion 111; if the first distance h1 is greater than 0 micrometer, it means that after the second electrode 12 flattens the abnormal protrusion 111, the area covered by the second electrode 12 on the abnormal protrusion 111 still has a weak protrusion.

[0110] Then proceed to step B3.

[0111] Please refer to Figure 7 Step B3, sequentially forming a light-emitting functional layer 13 and a third electrode 14 on the driving substrate 11. The light-emitting functional layer 13 at least includes a light-emitting material layer 131. The light-emitting material layer 131 continuously and entirely covers the second electrode 12, and the third electrode 14 covers the light-emitting functional layer 13.

[0112] It can be understood that the light emitting material layer 131 continuously and entirely covers the second electrode 12 to separate the short-circuit path between the first electrode 113 and the third electrode 14 , thereby preventing the first electrode 113 and the third electrode 14 from being short-circuited.

[0113] Optionally, the distance from the surface of the light emitting material layer 131 stacked with the second portion 122 away from the first electrode 113 to the surface of the second portion 122 away from the first electrode 113 is a second distance h2. The first distance h1 is less than or equal to half of the second distance h2.

[0114] It should be noted that the second distance h2 is the sum of the thickness of the light-emitting material layer 131 and the thickness of the film layer between the light-emitting material layer 131 and the second electrode 12. For example, when the light-emitting functional layer 13 only includes the light-emitting material layer 131, the second distance h2 is the thickness of the light-emitting material layer 131; for another example, when the light-emitting functional layer 13 includes a hole injection layer, a hole transport layer and a light-emitting material layer 131, the second distance h2 is the sum of the thicknesses of the hole injection layer, the hole transport layer and the light-emitting material layer 131.

[0115] The first distance h1 is less than or equal to half of the second distance h2 so that the light emitting material layer 131 can completely and continuously cover the second electrode 12 , so that the light emitting material layer 131 separates the short-circuit path between the first electrode 113 and the third electrode 14 .

[0116] In addition, it should be noted that based on the product specifications, the first electrode 113 and the second electrode 12 both have thickness specification requirements, which means that the thickness of the second electrode 12 cannot be increased arbitrarily, so that the large-sized abnormal protrusions 111 cannot be well flattened, resulting in the risk of short-circuiting the first electrode 113 and the third electrode 14 in the area of ​​the large-sized abnormal protrusions 111.

[0117] Therefore, in order to solve the problem of short circuit between the first electrode 113 and the third electrode 14 caused by the large-sized abnormal protrusion 111.

[0118] In some embodiments of the present application, before forming the second electrode 12 on the driving substrate 11 (step B2), the following steps are also included:

[0119] Please refer to Figure 8 , step B4a, obtaining a first real-time image in the opening 11a area, identifying the abnormal protrusion 111 and obtaining characteristic information of the abnormal protrusion 111 based on the comparison between the first real-time image and the standard image, wherein the characteristic information includes the protrusion height.

[0120] It is understandable that the camera 21 is used to photograph and / or scan the driving substrate 11 to obtain a first real-time image of the opening 11a region in the driving substrate 11. For example, an optical inspection device (AOI) may be used to obtain the first real-time image.

[0121] Then, the first real-time image is compared with the standard image, the abnormal protrusion is identified and the characteristic information of the abnormal protrusion is recorded. Wherein, this step and the step of obtaining the first real-time image can be processed in the optical detection device, or this step can be processed by an additional control device.

[0122] Secondly, since the abnormal protrusion 111 is higher than the first electrode 113, the light reflection brightness of the abnormal protrusion 111 is greater, and the greater the grayscale value of the image, the greater the brightness of the image. Therefore, the abnormal protrusion 111 can be identified by judging the size of the grayscale value of the image.

[0123] The protrusion height is the height of the feature body protruding from the plane where it is located. For example, the abnormal protrusion 111 is formed on the upper surface of the first electrode 113, and the distance from the farthest end of the abnormal protrusion 111 away from the first electrode 113 to the upper surface of the first electrode 113 is the protrusion height of the abnormal protrusion 111.

[0124] Optionally, the first real-time image includes at least one of a plan view image and a three-dimensional view image. The feature information of the abnormal protrusion 111 also includes position information and contour information, and the contour information is the outer contour shape, coordinates and size information of the abnormal protrusion 111 in the plan view. The position information is the midpoint coordinate information of the abnormal protrusion 111 in the plan view.

[0125] Among them, based on the irregularity of the abnormal protrusion 111, the position information of the abnormal protrusion 111 can be used for initial positioning and combined with the external contour coordinate information for secondary positioning, so as to finally lock the specific position of the abnormal protrusion 111.

[0126] Then proceed to step B4b.

[0127] Please refer to Fig. 9 , step B4b, if the protruding height of the abnormal protrusion 111 is less than or equal to half the thickness of the first electrode 113, then perform the step of forming a second electrode on the driving substrate 11 (step B2).

[0128] It is understandable that if the protrusion height of the abnormal protrusion 111 is less than or equal to half the thickness of the first electrode 113, the abnormal protrusion 111 is judged to be a small-sized abnormal protrusion 111. When the driving substrate 11 has a small-sized abnormal protrusion 111, step B2 can be started.

[0129] The protruding height of the abnormal protrusion 111 is less than or equal to half of the thickness of the first electrode 113 , so that the second electrode 12 can better flatten the abnormal protrusion 111 .

[0130] In some embodiments of the present application, after forming the second electrode 12 on the driving substrate 11 (step B2), and before sequentially forming the light-emitting functional layer and the third electrode on the driving substrate 11 (step B3), the following steps are also included:

[0131] Step B4c, acquiring a second real-time image in the opening 11a area, and judging whether the protruding height of the first portion 121 of the second electrode 12 is greater than half of the second distance h2 based on the comparison between the second real-time image and the standard image.

[0132] Optionally, the second real-time image is obtained in the same manner as the first real-time image. The second real-time image is then compared with the standard image to identify the abnormal protrusion and record the position information and contour information of the abnormal protrusion. This step and the step of obtaining the second real-time image can both be processed in the optical detection device, or this step can be processed by an additional control device.

[0133] After the second electrode 12 covers the abnormal protrusion 111, it is possible that the abnormal protrusion with a larger size is also well flattened, so that it is not necessary to remove the abnormal protrusion. Therefore, the protrusion height of the first part 121 of the second electrode 12 is used as a comparison object to more accurately determine whether the abnormal protrusion needs to be removed.

[0134] Then proceed to step B4d.

[0135] Please refer to Fig.10, step B4d, if yes, then according to the position information and the contour information, remove the abnormal protrusion 111 to form a hole 12a, and the depth of the hole 12a is greater than or equal to the sum of the thickness of the first electrode 113 and the second electrode 12.

[0136] It can be understood that if the protruding height of the first portion 121 of the second electrode 12 is greater than half of the second distance h2, the abnormal protrusion 111 is determined to be a large-sized abnormal protrusion 111.

[0137] Since the abnormal protrusion 111 is covered by the second electrode 12, it is impossible to determine whether the protrusion originates from the upper surface or the lower surface of the first electrode 113 according to the second real-time image. Therefore, the depth of the hole 12a is greater than or equal to the sum of the thicknesses of the first electrode 113 and the second electrode 12, so as to ensure that the abnormal protrusion 111 is removed by over-digging.

[0138] Secondly, the data of the second distance h2 is stored in the storage module and can be obtained at any time according to the demand. The second distance h2 has different values ​​according to different display panel specifications, and the corresponding data of the second distance h2 can be obtained according to the display panel specifications.

[0139] Secondly, based on the product specifications, the light-emitting material layer 131, the hole transport layer and the hole injection layer all have thickness specification requirements, which means that the thickness of the light-emitting material layer 131, the hole transport layer and the hole injection layer cannot be increased at will. Therefore, when the protruding height (first distance h1) of the first portion 121 of the second electrode 12 is greater than half of the second distance h2, the light-emitting material layer 131 may not be able to cover the entire surface of the second electrode 12, resulting in the risk of short-circuiting the first electrode 113 and the third electrode 14. Therefore, it is necessary to remove the large-sized abnormal protrusions 111 to avoid short-circuiting the first electrode 113 and the third electrode 14.

[0140] Optionally, removing the abnormal protrusion 111 to form the hole 12a further includes the following steps:

[0141] Step B4d1, based on the position information and the contour information of the abnormal protrusion 111, obtain the contour line information of the hole 12a and generate the first contour line trajectory of the hole 12a. The first contour trajectory of the hole 12a is formed based on the contour line of the abnormal protrusion 111 extending outward by a set distance, and the set distance is between 0.4 microns and 1 micron.

[0142] It can be understood that, based on the contour information of the abnormal protrusion 111, a first contour trajectory having a range larger than the contour is formed to excessively remove the abnormal protrusion to improve the cleanliness of removing the abnormal protrusion.

[0143] Among them, the larger the set distance is, the larger the range that needs to be removed is, and the larger the size of the hole 12a is. Therefore, in order to avoid the hole 12a being too large and to ensure the cleanliness of removing abnormal protrusions, the set distance is selected to be between 0.4 microns and 1 micron, for example, it can be 0.4 microns, 0.5 microns, 0.6 microns, 0.7 microns, 0.8 microns, 0.9 microns or 1 micron.

[0144] Then go to step B4d2.

[0145] Step B4d2, determining whether the first contour line trajectory is within the inner contour of the opening 11a.

[0146] Then go to step B4d3 or step B4d4.

[0147] Step B4d3: if the first contour line trajectory is within the inner contour of the opening 11a, then according to the first contour line trajectory, the abnormal protrusion 111 is removed to form a hole 12a.

[0148] Step B4d4, if the first contour line trajectory partially exceeds the inner contour of the opening 11a, remove the portion of the first contour line trajectory exceeding the inner contour of the opening 11a to generate a second contour line trajectory, and according to the second contour line trajectory, remove the abnormal protrusion 111 to form a hole 12a.

[0149] It should be explained that the contour trajectory of the hole 12a does not exceed the inner contour of the opening 11a, so as to ensure the consistency of the shape and size of the opening 11a and reduce the risk of uneven light emission of sub-pixels.

[0150] Then go to step B4f.

[0151] Please refer to Fig.11 , step B4f, use repair material 15 to fill the hole 12a.

[0152] Optionally, the repair material 15 is filled in the hole 12 a by inkjet printing, that is, the repair material 15 is used to fill the hole 12 a to improve the flatness of the second electrode 12 .

[0153] The hole 12a is repaired by inkjet printing. Based on the liquid properties of the raw material of the repair material 15, it has leveling properties, which can better fill the hole 12a and accurately repair the hole 12a.

[0154] Optionally, the surface of the repair material 15 is flush with the surface of the second electrode 12 .

[0155] It should be understood that due to the accuracy of the equipment, the repair material 15 cannot actually be completely flush with the surface of the second electrode 12 , so the surface of the repair material 15 is substantially flush with the surface of the second electrode 12 .

[0156] In some embodiments, the repair material 15 may be a conductive material. The conductive material is used to fill the hole 12 a so that the hole 12 a area can emit light normally, further improving the effect of dark spots.

[0157] In some embodiments, the repair material 15 is selected from the material of the second electrode 12 , so that the conductive property and optical property of the repair material 15 are close to or equal to the conductive property and optical property of the second electrode 12 , thereby improving the luminous uniformity of the sub-pixel.

[0158] Optionally, step B4f includes the following steps:

[0159] Step B4f1, obtaining film layer information of the second electrode 12, wherein the film layer information includes the number of film layers, material information of each film layer, and thickness information of each film layer.

[0160] For example, if the second electrode 12 is an ITO single-layer film, the number of film layers of the second electrode 12 is 1, the material information is ITO, and the film thickness is n micrometers. For another example, if the second electrode 12 is ITO / Ag / ITO, the number of film layers of the second electrode 12 is 3; the material information is that the materials of the first and third film layers are ITO, and the material of the second film layer is Ag; the thickness of the first film layer is m1, the thickness of the second film layer is m2, the thickness of the third film layer is m3, and the thickness of the second film layer is the largest.

[0161] Then go to step B4f2 or step B4f3.

[0162] Step B4f2: if the number of the film layer is one layer, then the same material as the second electrode 12 is selected as the repair material 15 to fill the hole 12a.

[0163] Step B4f3, if the number of film layers is at least two, select the same material as the thickest film layer in the second electrode 12 as the repair material 15 to fill the hole 12a, or, according to the order of the film layers, select the same material as the corresponding film layer in the second electrode 12 as the repair material 15 to repair the hole 12a.

[0164] In some embodiments of the present application, the method for preparing the display panel adopts a method of covering the small-sized abnormal protrusions 111 with the second electrode in combination with removing the large-sized abnormal protrusions 111 to reduce the risk of short-circuiting the first electrode 113 and the third electrode 14 .

[0165] The above is a detailed introduction to a display panel and a preparation method thereof provided in an embodiment of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for preparing a display panel, characterized in that: The following steps are involved: A driving substrate is provided, the driving substrate comprising an abnormal protrusion, a flat layer, a first electrode and a pixel definition layer, the first electrode is arranged on the flat layer, the pixel definition layer is arranged on the first electrode, a plurality of openings are opened on the pixel definition layer, one of the openings correspondingly exposes one of the first electrodes, at least some of the plurality of openings have the abnormal protrusion in them, and the abnormal protrusion is formed on a side of the first electrode away from the flat layer; forming a second electrode on the driving substrate, wherein the second electrode is disposed in the opening and covers the abnormal protrusion and the first electrode; A light-emitting functional layer and a third electrode are sequentially formed on the driving substrate, wherein the light-emitting functional layer at least includes a light-emitting material layer, the light-emitting material layer continuously and entirely covers the second electrode, and the third electrode covers the light-emitting functional layer.

2. The method for preparing a display panel according to claim 1, characterized in that: The second electrode includes a first part and a second part connected to the first part, the first part covers the abnormal protrusion, the second part covers and is connected to the first electrode, a first distance exists between a side of the first part away from the first electrode and a surface of the second part away from the first electrode, and the first distance is greater than or equal to 0 microns; a second distance exists between a surface of the light-emitting material layer stacked with the second part away from the first electrode and a surface of the second part away from the first electrode, and the first distance is less than or equal to half of the second distance.

3. The method for preparing a display panel according to claim 2, characterized in that: Forming a second electrode on the driving substrate comprises the following steps: forming an electrode material layer on the driving substrate, wherein the electrode material layer entirely covers the driving substrate; The electrode material layer is patterned to form a plurality of second electrodes, each of the openings is provided with a corresponding second electrode, in the opening with an abnormal protrusion, the second electrode covers the abnormal protrusion and the first electrode, and in the opening without the abnormal protrusion, the second electrode covers the first electrode.

4. The method for preparing a display panel according to any one of claims 1 to 3, characterized in that: Before forming the second electrode on the driving substrate, the method further includes the following steps: Acquire a first real-time image in the opening area, identify the abnormal protrusion and acquire characteristic information of the abnormal protrusion based on the comparison between the first real-time image and the standard image, wherein the characteristic information includes the protrusion height; If the protrusion height of the abnormal protrusion is less than or equal to half of the thickness of the first electrode, the step of forming a second electrode on the driving substrate is performed.

5. The method for preparing a display panel according to claim 4, characterized in that: The characteristic information of the abnormal protrusion also includes position information and contour information; after forming the second electrode on the drive substrate and before sequentially forming the light-emitting functional layer and the third electrode on the drive substrate, the following steps are also included: Acquire a second real-time image in the opening area, and determine whether a protruding height of the first portion of the second electrode is greater than half of the second distance based on a comparison between the second real-time image and a standard image; If yes, then according to the position information and the contour information, removing the abnormal protrusion to form a hole, the depth of the hole being greater than or equal to the sum of the thicknesses of the first electrode and the second electrode; The excavated hole is filled with a patching material.

6. The method for preparing a display panel according to claim 5, characterized in that: Filling the excavated hole with a repair material comprises the following steps: Acquire film layer information of the second electrode, wherein the film layer information includes the number of film layers, material information of each film layer, and thickness information of each film layer; If the number of the film layers is one, the same material as the second electrode is selected as the repair material to fill the hole; If the number of film layers is at least two, the same material as the thickest film layer in the second electrode is selected as the repair material to fill the hole, or, according to the order of the film layers, the same material as the corresponding film layers in the second electrode is selected in sequence as the repair material to repair the hole.

7. The method for preparing a display panel according to claim 6, characterized in that: Removing the abnormal protrusion to form a hole also includes the following steps: According to the position information and the contour information of the abnormal protrusion, the contour line information of the hole is obtained and a first contour line trajectory of the hole is generated, wherein the first contour line of the hole is formed by extending the contour line of the abnormal protrusion outward by a set distance, and the set distance is between 0.4 micrometers and 1 micrometer; determining whether the first contour line trajectory is within the inner contour of the opening; If the first contour line track is within the inner contour of the opening, then according to the first contour line track, the abnormal protrusion is removed to form the excavated hole; If part of the first contour line trajectory exceeds the inner contour of the opening, the part of the first contour line trajectory exceeding the inner contour of the opening is removed to generate a second contour line trajectory, and the abnormal protrusion is removed according to the second contour line trajectory to form the hole.

8. A display panel, characterized in that: include: A driving substrate, the driving substrate comprising an abnormal protrusion, a flat layer, a first electrode and a pixel definition layer, the first electrode is arranged on the flat layer, the pixel definition layer is arranged on the first electrode, a plurality of openings are opened on the pixel definition layer, one of the openings correspondingly exposes one of the first electrodes, at least some of the plurality of openings have the abnormal protrusion in them, and the abnormal protrusion is formed on a side of the first electrode away from the flat layer; a second electrode, in the opening having the abnormal protrusion, the second electrode being disposed in the opening and covering the abnormal protrusion and the first electrode; a light-emitting functional layer, covering the second electrode, wherein the light-emitting functional layer at least comprises a light-emitting material layer, and the light-emitting material layer continuously and entirely covers the second electrode; as well as The third electrode covers the light-emitting functional layer.

9. The display panel according to claim 8, characterized in that: The second electrode includes a first portion and a second portion connected to the first portion, the first portion covers the abnormal protrusion, the second portion covers and is connected to the first electrode, a first distance exists between a side of the first portion away from the first electrode and a surface of the second portion away from the first electrode, and the first distance is greater than or equal to 0 micrometers; A distance from a surface of the light-emitting material layer stacked with the second portion away from the first electrode to a surface of the second portion away from the first electrode is a second distance, and the first distance is less than or equal to half of the second distance.

10. The display panel according to claim 9, characterized in that: The thickness of the second electrode is greater than the thickness of the first electrode.

11. The display panel according to any one of claims 8 to 10, characterized in that: A hole is formed on the electrode structure formed by stacking the first electrode and the second electrode, and the depth of the hole is greater than or equal to the thickness of the electrode structure; The excavated hole is filled with a repair material, and the repair material is at least partially the same as the material of the electrode structure.

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