OLED display panel, OLED display screen and preparation method

Abstract

The application provides an OLED display panel, an OLED display screen and a preparation method, relates to the technical field of display, solves the problem that film layer residues exist when an electroluminescent layer is removed by using a laser drilling method, and causes poor contact. The method comprises the following steps: providing a substrate; sequentially forming an anode layer, an auxiliary electrode layer, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer and an electron injection layer on the substrate; removing all film layers above the region where the auxiliary electrode layer is located, and forming a through hole; introducing conductive particles into the through hole, and forming a micro-conductive layer at the bottom of the through hole; forming a cathode layer on the electron injection layer and in the space formed by the through hole and the micro-conductive layer, and the cathode layer is electrically connected with the auxiliary electrode layer through the micro-conductive layer. The application forms a micro-conductive layer at the bottom of the through hole, and the cathode layer is in good contact with the auxiliary electrode layer and is conductive, thereby solving the problem that the voltage drop of the display panel is still large, and improving the display unevenness of the OLED display panel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to an OLED display panel, an OLED display screen and a preparation method. BACKGROUND

[0002] As one of the pillar industries of electronic information industry, flat panel display industry is of great economic effect and industrial agglomeration effect, and is very important for the development of technology and economy of a country or region. Although the liquid crystal display technology of thin film transistor liquid crystal display (TFT-LCD) occupies the mainstream of current display, the active-matrix organic light-emitting diode (AMOLED) technology is most likely to replace the TFT-LCD technology and become the next generation of new display technology.

[0003] In the manufacture of large-size OLED panels, the mainstream method is to use vacuum evaporation or ink jet printing (IJP) technology to prepare the layer structure of the OLED panel. Because the cathode surface resistance increases with the size, there is a large difference in voltage drop between the center and the edge of the cathode, which will cause display unevenness (Mura) of the product. To solve this problem, after the auxiliary electrode is prepared, the electroluminescence (EL) layer (between the cathode and the auxiliary electrode) is removed by laser punching, and then the connection structure of the cathode and the bottom auxiliary electrode is prepared. When the OLED device structure is prepared by ink jet printing (IJP), the above-mentioned method can be used to remove the ETL functional layer, but there is a problem of residual ink jet printing film layer, which leads to poor contact and limited improvement of Mura. SUMMARY

[0004] The present application provides an OLED display panel, an OLED display screen and a preparation method, which can better improve the voltage drop problem in the panel and improve the display unevenness problem of the OLED display panel.

[0005] In one aspect, the present application provides a preparation method of an OLED display panel, which comprises:

[0006] providing a substrate on which a pixel array has been formed;

[0007] forming an anode layer, an auxiliary electrode layer, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer and an electron injection layer on the substrate in sequence;

[0008] Remove all film layers above the area where the auxiliary electrode layer is located, and form through holes;

[0009] Conductive particles are introduced into the through hole, and a micro-conductive layer is formed at the bottom of the through hole;

[0010] A cathode layer is formed on the electron injection layer and in the space formed by the via and the micro-conductive layer. The cathode layer is electrically connected to the auxiliary electrode layer through the micro-conductive layer.

[0011] In one possible implementation of this application, before introducing conductive particles into the via and forming a micro-conductive layer at the bottom of the via, the method includes:

[0012] A photomask is used above the electron injection layer to block out the area other than the area where the via is located, thereby exposing the via.

[0013] In one possible implementation of this application, the step of introducing conductive particles into the through-hole and forming a micro-conductive layer at the bottom of the through-hole includes:

[0014] Conductive particles are introduced into the through-hole by sputtering or vacuum evaporation, and a micro-conductive layer is formed at the bottom of the through-hole.

[0015] In one possible implementation of this application, the thickness of the micro-conductive layer is 1 / 10 to 3 / 10 of the depth of the via.

[0016] In one possible implementation of this application, the conductive particles include aluminum particles, silver particles, magnesium particles, or alloy particles composed of any two of them.

[0017] In one possible implementation of this application, the step of removing all film layers above the region where the auxiliary electrode layer is located and forming a via includes:

[0018] All film layers above the area where the auxiliary electrode layer is located are removed by laser drilling to form the through hole.

[0019] In one possible implementation of this application, the sequential formation of an anode layer, an auxiliary electrode layer, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer on the substrate includes:

[0020] The hole injection layer, hole transport layer, and light emission layer are formed sequentially using inkjet printing.

[0021] In one possible implementation of this application, the sequential formation of an anode layer, an auxiliary electrode layer, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer on the substrate includes:

[0022] The electron transport layer and the electron injection layer are formed in sequence by vacuum evaporation.

[0023] In another aspect, the present application provides an OLED display panel, which is prepared by the method for preparing an OLED display panel as described.

[0024] In another aspect, the present application provides an OLED display screen, which adopts the OLED display panel as described.

[0025] The present application forms an anode layer, an auxiliary electrode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer on a substrate on which a pixel array has been formed, removes all film layers above the region where the auxiliary electrode layer is located, forms a through hole, introduces conductive particles into the through hole, forms a micro-conductive layer at the bottom of the through hole, forms a cathode layer on the electron injection layer and in the space formed by the through hole and the micro-conductive layer, and the cathode layer is electrically connected to the auxiliary electrode layer through the micro-conductive layer. When the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer and the electron injection layer above the auxiliary electrode layer are removed, if there is residual film layer that has not been completely removed, a small conductive path can be formed in the through hole through the micro-conductive layer, so that the cathode layer and the auxiliary electrode layer are in good contact and conductive, avoiding the problem that the central and edge voltage drops of the cathode layer are still large due to the residual film layer that has not been completely removed, and further improving the display unevenness problem of the OLED display panel. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0027] Figure 1 is a structural schematic diagram of an OLED panel in the prior art;

[0028] Figure 2 is a flowchart of the method for preparing an OLED display panel provided in the embodiments of the present application;

[0029] Figure 3 is a structural schematic diagram in the preparation process of the OLED display panel provided in the embodiments of the present application;

[0030] Figure 4 is a structural schematic diagram in the preparation process of the OLED display panel provided in the embodiments of the present application;

[0031] Figure 5is a structural schematic diagram in a preparation process of an OLED display panel provided in an embodiment of the present application.

[0032] Figure 6 is a structural schematic diagram in a preparation process of an OLED display panel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0034] In the description of the present application, it should be understood that, in addition, the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0035] In the present application, the word "exemplary" is used to mean "serving as an example, instance, or illustration." Any implementation described as "exemplary" in the present application is not necessarily to be construed as preferred or advantageous over other implementations. The following description is presented to enable any person skilled in the art to make and use the application. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present application. It should be appreciated that one skilled in the art can realize the present application without the use of these specific details. In other instances, well-known structures and processes are not elaborated in order not to obscure the description of the present application with unnecessary detail. Therefore, the present application is not intended to be limited by the embodiments shown, but is to be accorded with the widest scope consistent with the principles and features disclosed herein.

[0036] The current OLED panel display technology does not need to use a backlight, but emits light by itself through a light-emitting layer. For example, as shown in FIG. 1, an OLED panel 100 includes a substrate 110, a first electrode 120, a light-emitting layer 130, and a second electrode 140. Figure 1As shown, the OLED panel includes an anode layer 11, a hole injection layer 12 (HIL), a hole transport layer 13 (HTL), an emitting layer 14 (EML), an electron transport layer 15 (ETL), an electron injection layer 16 (EIL), and a cathode layer 17, which are stacked sequentially. An electric field is applied to the anode layer 11 and the cathode layer 17 by energizing them. Electrons and holes are injected into the electron injection layer 16 and the hole injection layer 12, respectively, and then migrate from the electron transport layer 15 and the hole transport layer 13 to the emitting layer 14, where they recombine to generate excitons. These excitons migrate under the influence of the electric field, transferring their energy to the emitting molecules and causing them to produce photons, thus achieving light emission.

[0037] This application provides an OLED display panel, an OLED display screen, and a manufacturing method thereof, which will be described in detail below.

[0038] like Figure 2 The diagram shown is a flowchart of an embodiment of the method for fabricating an OLED display panel according to this application. The method for fabricating the OLED display panel includes the following steps:

[0039] 101. A substrate with a pixel array already formed thereon is provided;

[0040] 102. An anode layer 11, an auxiliary electrode layer 20, a hole injection layer 12, a hole transport layer 13, a light-emitting layer 14, an electron transport layer 15, and an electron injection layer 16 are sequentially formed on a substrate, forming a structure as shown in the figure. Figure 3 The structure shown;

[0041] 103. Remove all film layers above the area where the auxiliary electrode layer 20 is located, and form through holes 18, forming as shown in the figure. Figure 4 The structure shown;

[0042] 104. Conductive particles are introduced into the through-hole 18, and a micro-conductive layer 19 is formed at the bottom of the through-hole 18, forming a structure as shown in the figure. Figure 5 The structure shown;

[0043] 105. A cathode layer 17 is formed on the electron injection layer 16 and within the space formed by the via 18 and the micro-conductive layer 19. The cathode layer 17 is electrically connected to the auxiliary electrode layer 20 through the micro-conductive layer 19, forming a structure as shown in the figure. Figure 6 The structure shown.

[0044] The application forms the via hole 18 by removing all film layers above the area where the auxiliary electrode layer 20 is located, introduces conductive particles into the via hole 18, and forms the micro-conductive layer 19 at the bottom of the via hole 18. Then, the cathode layer 17 is formed on the electron injection layer 16 and in the space formed by the via hole 18 and the micro-conductive layer 19. The cathode layer 17 is electrically connected to the auxiliary electrode layer 20 through the micro-conductive layer 19. When the film layers above the auxiliary electrode layer 20, i.e., the hole injection layer 12, the hole transport layer 13, the light-emitting layer 14, the electron transport layer 15, and the electron injection layer 16, are removed, if there is residual film layer that is not removed completely, a micro-conductive path can be formed in the via hole 18 through the micro-conductive layer 19, so that the cathode layer 17 and the auxiliary electrode layer 20 are in good contact and conductive. Thus, the problem that the central and edge voltage drops of the cathode layer 17 are still large due to the residual film layer that is not removed completely is avoided, and the display unevenness of the OLED display panel is improved.

[0045] In the embodiment, the pixel array can be formed on the substrate by using a pixel array manufacturing method disclosed in the prior art, which will not be described herein.

[0046] The anode layer 11 with a predetermined pattern can be prepared by using a vacuum evaporation process or an etching process. For example, the etching process is used to form a full metal layer on the substrate by using a method including but not limited to a physical vapor deposition (PVD) method. The metal layer can be a transparent ITO (Indium Tin Oxide) film, or other metal layer that can realize electrical conductivity, which is not specifically limited in the embodiment.

[0047] In the embodiment, the cathode layer 17 can be manufactured by using the same manufacturing process as the anode layer 11. The material of the cathode layer 17 can be a metal such as aluminum, calcium, or magnesium, or an alloy of any of the metals and a noble metal such as gold or silver.

[0048] In the embodiment, before the conductive particles are introduced into the via hole 18 and the micro-conductive layer 19 is formed at the bottom of the via hole 18, the method includes: using a mask to shield other areas except the area where the via hole 18 is located, so as to expose the via hole 18. The mask is provided with a light-transmitting area that allows light to pass through and a light-shielding area that shields light. The light-transmitting area is located at the area where the via hole 18 is located, and other areas of the electron injection layer 16 are located in the light-shielding area.

[0049] Subsequently, the conductive particles are introduced into the via hole 18 by using a sputtering method or a vacuum evaporation method, and the micro-conductive layer 19 is formed at the bottom of the via hole 18.

[0050] In the embodiment, the thickness of the micro-conductive layer 19 is 1 / 10-3 / 10 of the depth of the through hole 18. Controlling the thickness of the micro-conductive layer 19 to be 1 / 10-3 / 10 of the depth of the through hole 18 can ensure that the micro-conductive layer 19 is completely formed in the through hole and ensure the conductivity of the micro-conductive layer 19, thereby ensuring that the cathode layer 17 can be in good contact with the auxiliary electrode layer 20 through the micro-conductive layer 19.

[0051] In the embodiment, the conductive particles include aluminum particles, silver particles, magnesium particles, or alloy particles formed by any two of the above, and other conductive particles that can realize conductivity can also be used, which are not specifically limited in the embodiment.

[0052] In the embodiment, a laser drilling method is used to remove all film layers above the region where the auxiliary electrode layer 20 is located and form the through hole 18.

[0053] In the embodiment, an inkjet printing method is used to sequentially form the hole injection layer 12, the hole transport layer 13, and the light-emitting layer 14. The manufacturing materials of the hole injection layer 12 and the hole transport layer 13 can be aromatic amine fluorescent compounds, and the light-emitting layer 14 can be made of organic fluorescent materials, which have the characteristics of strong fluorescence in solid state, good carrier transport performance, good thermal stability and chemical stability, and high quantum efficiency.

[0054] In the embodiment, a vacuum evaporation method is used to sequentially form the electron transport layer 15 and the electron injection layer 16. The materials used for the electron transport layer 15 and the electron injection layer 16 can be organic conductive materials.

[0055] In another embodiment of the present application, an OLED display panel is provided, which is made by the preparation method of the OLED display panel as described above.

[0056] In another embodiment of the present application, an OLED display screen is provided, which uses the OLED display panel as described above.

[0057] The above describes in detail the OLED display panel, the OLED display screen, and the preparation method provided by the embodiments of the present application. The principles and implementation manners of the present application are described by using specific examples, and the above embodiment descriptions are only used to help understand the method and the core idea of the present application. Meanwhile, for those skilled in the art, the specific implementation manners and application ranges can be changed according to the idea of the present application, and the above description should not be understood as limiting the present application.

Claims

1. A method for manufacturing an OLED display panel, characterized in that, The method comprises: providing a substrate formed with a pixel array; forming an anode layer, an auxiliary electrode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer on the substrate in sequence, the anode layer, the auxiliary electrode layer, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer and the electron injection layer being arranged in different layers; removing all film layers above the area where the auxiliary electrode layer is located and forming a through hole; introducing conductive particles into the through hole by sputtering or vacuum evaporation and forming a micro-conductive layer at the bottom of the through hole; the thickness of the micro-conductive layer is 1 / 10-3 / 10 of the depth of the through hole; the conductive particles include aluminum particles, silver particles, magnesium particles or alloy particles composed of any two of them; forming a cathode layer on the electron injection layer and in the space formed by the through hole and the micro-conductive layer, the cathode layer being electrically connected to the auxiliary electrode layer through the micro-conductive layer.

2. The method for preparing an OLED display panel as described in claim 1, characterized in that, Before the step of introducing conductive particles into the through hole and forming a micro-conductive layer at the bottom of the through hole, the method comprises: shielding other areas except the area where the through hole is located by using a mask above the electron injection layer, thereby exposing the through hole.

3. The method for preparing an OLED display panel as described in claim 1, characterized in that, The step of removing all film layers above the area where the auxiliary electrode layer is located and forming a through hole comprises: removing all film layers above the area where the auxiliary electrode layer is located by laser drilling and forming the through hole.

4. The method for preparing an OLED display panel as described in claim 1, characterized in that, The step of forming an anode layer, an auxiliary electrode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer on the substrate in sequence comprises: forming a hole injection layer, a hole transport layer and a light emitting layer in sequence by inkjet printing.

5. The method for preparing an OLED display panel as described in claim 1, characterized in that, The step of forming an anode layer, an auxiliary electrode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer on the substrate in sequence comprises: forming an electron transport layer and an electron injection layer in sequence by vacuum evaporation.

6. An OLED display panel, characterized in that, The OLED display panel is made by the method for manufacturing an OLED display panel according to any one of claims 1-5.

7. An OLED display screen, characterized by The OLED display screen is the OLED display panel according to claim 6.

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