WO2020232819A1

WO2020232819A1 - Fabrication method for oled display panel and oled display panel

Info

Publication number: WO2020232819A1
Application number: PCT/CN2019/097143
Authority: WO
Inventors: 杜中辉; 吴元均
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2019-05-23
Filing date: 2019-07-22
Publication date: 2020-11-26
Also published as: CN110137365A; CN110137365B

Abstract

Provided by the present invention are a fabrication method for an OLED display panel and an OLED display panel. The method comprises the following steps: providing a base substrate, and forming on the base substrate a plurality of anodes arranged in an array and an auxiliary electrode located within an interval region of the plurality of anodes; forming a pixel defining layer on the base substrate, the plurality of anodes and the auxiliary electrode, and forming on the pixel defining layer a plurality of first openings that respectively correspond above the plurality of anodes as well as a second opening corresponding above the auxiliary electrode; forming an OLED light-emitting layer covering the entire surface on the auxiliary electrode, the pixel defining layer, and the plurality of anodes; performing UV illumination on the OLED light-emitting layer; and forming cathodes distributed on the entire surface on the OLED light-emitting layer. By means of UV illumination, the electrical current conductivity of an electron transmission material in the OLED light-emitting layer may be improved, conductivity obstacles between the auxiliary electrode and the cathodes may be eliminated, and voltage drop enhancement effect may be improved.

Description

Manufacturing method of OLED display panel and OLED display panel

Technical field

The present invention relates to the field of display technology, in particular to a manufacturing method of an OLED display panel and an OLED display panel.

Background technique

Organic Light Emitting Display (OLED) has self-luminescence, low driving voltage, high luminous efficiency, short response time, high definition and contrast, close to 180° viewing angle, wide operating temperature range, and can realize flexible display and Large-area full-color display and many other advantages are recognized by the industry as the display device with the most potential for development.

OLED can be divided into passive matrix OLED (Passive Matrix OLED, PMOLED) and active matrix OLED (Active Matrix OLED, AMOLED) are two categories, namely direct addressing and thin film transistor matrix addressing. Among them, AMOLED has pixels arranged in an array, is an active display type, has high luminous efficiency, and is generally used as a high-definition large-size display device.

OLED usually includes: a substrate, an anode provided on the substrate, a hole injection layer provided on the anode, a hole transport layer provided on the hole injection layer, a light emitting layer provided on the hole transport layer, and a light emitting layer provided on the hole transport layer. The electron transport layer on the layer, the electron injection layer provided on the electron transport layer, and the cathode provided on the electron injection layer. The light-emitting principle of OLED display devices is that semiconductor materials and organic light-emitting materials are driven by an electric field to cause light emission through carrier injection and recombination. Specifically, OLED display devices usually use ITO pixel electrodes and metal electrodes as the anode and cathode of the device, respectively. Under a certain voltage drive, electrons and holes are injected from the cathode and anode to the electron transport layer and hole transport layer, respectively. Holes migrate to the light-emitting layer through the electron transport layer and the hole transport layer respectively, and meet in the light-emitting layer to form excitons and excite light-emitting molecules. The latter emit visible light through radiation relaxation.

With the development of display technology, the size of display panels has become larger and larger, and the size of the cathode of OLED display panels has become larger and larger, and the resistance of the cathode has also increased correspondingly, causing the voltage applied to the cathode to be lower than the target value. Down (IR Drop). To this end, the prior art proposes a technical solution of arranging a separate auxiliary electrode in the same layer as the anode under the cathode. hole) Connecting the cathode and the auxiliary electrode together can effectively reduce the sheet resistance of the cathode and improve the voltage drop. However, in actual application, after the opening is formed, the OLED light-emitting function layer, including the electron transport layer, needs to be formed. The OLED light-emitting function layer is also deposited in the opening. The cathode and the auxiliary electrode need to pass through the electron transport layer to connect together. The material impedance of the electron transport layer is high, which makes the current through the opening too small, resulting in the conduction of the cathode and the auxiliary electrode. There are obstacles to pass, which affect the improvement effect of voltage drop.

technical problem

The purpose of the present invention is to provide a method for manufacturing an OLED display panel, which can improve the current conductivity of the electron transport layer, eliminate the conduction barrier between the auxiliary electrode and the cathode, and improve the voltage drop improvement effect.

The object of the present invention is also to provide an OLED display panel, which can improve the current conductivity of the electron transport layer, eliminate the conduction barrier between the auxiliary electrode and the cathode, and improve the voltage drop improvement effect.

Technical solutions

To achieve the above objective, the present invention provides a manufacturing method of an OLED display panel, which includes the following steps:

Step S1: Provide a base substrate, on which a plurality of anodes arranged in an array and an auxiliary electrode located in a spacing area of the plurality of anodes are formed;

Step S2. A pixel defining layer is formed on the base substrate, a plurality of anodes and auxiliary electrodes, and a plurality of first openings corresponding to the plurality of anodes and a plurality of first openings corresponding to the auxiliary electrodes are formed on the pixel defining layer. Second opening

Step S3, forming an OLED light emitting layer covering the entire surface on the auxiliary electrode, the pixel defining layer and the multiple anodes;

Step S4, applying UV light to the OLED light-emitting layer;

Step S5, forming cathodes distributed over the entire surface of the OLED light-emitting layer.

In the step S4, when the OLED light-emitting layer is irradiated with UV light, only the OLED light-emitting layer located in the second opening is irradiated with UV light.

The step S4 is performed on the UV light emitting layer of the OLED, wherein the UV light low-pressure mercury lamp, the UV light wavelength of 250 ~ 260nm, illumination 25 ~ 30 mW / cm ^2, when UV light is longer than, or Equal to 600 seconds.

The step S3 specifically includes:

Step S31, forming a hole injection layer covering the entire surface on the auxiliary electrode, the pixel defining layer and the multiple anodes;

Step S32, forming an entire surface covering hole transport layer on the hole injection layer;

Step S33, forming a plurality of light-emitting function layers corresponding to the plurality of anodes on the hole transport layer;

Step S34, forming an electron transport layer covering the entire surface on the hole transport layer and the light emitting function. The hole injection layer, the hole transport layer, the light emitting function layer and the electron transport layer together constitute the OLED light emitting layer.

In the step S34, the electron transport layer is formed by an evaporation process.

The material of one of the anode and the cathode is transparent oxide, and the material of the other is metal.

The material of the auxiliary electrode is transparent oxide.

The material of the auxiliary electrode is metal.

The auxiliary electrodes are distributed in a grid pattern.

The present invention also provides an OLED display panel, which is manufactured using the above-mentioned manufacturing method of the OLED display panel.

Beneficial effect

Beneficial effects of the present invention: The present invention provides a method for manufacturing an OLED display panel, which includes the following steps: step S1, providing a base substrate, and forming a plurality of anodes arranged in an array on the base substrate Step S2, forming a pixel definition layer on the base substrate, the plurality of anodes, and the auxiliary electrode, and forming a plurality of pixel definition layers corresponding to above the plurality of anodes on the pixel definition layer. The first opening and the second opening corresponding to the auxiliary electrode; step S3, forming an OLED light-emitting layer covering the entire surface on the auxiliary electrode, the pixel definition layer and the multiple anodes; step S4, performing the OLED light-emitting layer UV light; step S5, forming cathodes distributed across the entire surface of the OLED light-emitting layer, UV light treatment can improve the current conductivity of the electron transport material in the OLED light-emitting layer, and eliminate the barriers to conduction between the auxiliary electrode and the cathode, Improve the voltage drop improvement effect. The present invention also provides an OLED display panel, which can improve the current conductivity of the electron transport layer, eliminate the conduction barrier between the auxiliary electrode and the cathode, and improve the voltage drop improvement effect.

Description of the drawings

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and accompanying drawings of the present invention. However, the accompanying drawings are only provided for reference and illustration and are not used to limit the present invention.

In the attached picture,

FIG. 1 is a schematic diagram of step S1 of the manufacturing method of the OLED display panel of the present invention;

2 is a schematic diagram of step S2 of the manufacturing method of the OLED display panel of the present invention;

3 is a schematic diagram of step S3 of the manufacturing method of the OLED display panel of the present invention;

4 is a schematic diagram of step S4 of the first embodiment of the manufacturing method of the OLED display panel of the present invention;

5 is a schematic diagram of step S4 of the second embodiment of the manufacturing method of the OLED display panel of the present invention;

6 is a schematic diagram of step S5 of the manufacturing method of the OLED display panel of the present invention;

7 is a schematic diagram of step S6 of the manufacturing method of the OLED display panel of the present invention;

FIG. 8 is a flowchart of the manufacturing method of the OLED display panel of the present invention;

Figure 9 is a current-voltage curve diagram of the electron transport material ET1 before and after UV irradiation;

Figure 10 is the current-voltage curve diagram of the electron transport material ET2 before and after UV irradiation.

Embodiments of the invention

In order to further explain the technical means adopted by the present invention and its effects, the following describes in detail the preferred embodiments of the present invention and the accompanying drawings.

Referring to FIG. 7, the present invention provides a manufacturing method of an OLED display panel, including the following steps:

Step S1, please refer to FIG. 1 to provide a base substrate 10 on which a plurality of anodes 21 arranged in an array and an auxiliary electrode 22 located in a spaced area of the plurality of anodes 21 are formed.

Specifically, the base substrate 10 is a TFT substrate on which a TFT array and a flat layer covering the TFT array are formed, and the plurality of anodes 21 and auxiliary electrodes 22 are all formed on the flat layer.

Specifically, in some embodiments of the present invention, the material of the anode 21 is a transparent oxide, preferably indium tin oxide. Of course, this is not a limitation of the present application. In other embodiments of the present invention, the anode 21 is also Can be metal.

Specifically, in some embodiments of the present invention, the material of the auxiliary electrode 22 is the same as the material of the anode 21, and both are transparent oxides, preferably indium tin oxide. Of course, in other embodiments of the present invention, The material of the auxiliary electrode 22 may also be different from the material of the anode 21. The material of the auxiliary electrode 22 may be a metal, preferably one or a combination of silver, aluminum and copper.

Specifically, the auxiliary electrodes 22 are distributed in a grid pattern.

Step S2, referring to FIG. 2, forming a pixel defining layer 30 on the base substrate 10, the plurality of anodes 21, and the auxiliary electrode 22, and forming the pixel defining layer 30 on the pixel defining layer 30 corresponding to the plurality of anodes 21 respectively. A first opening 31 and a second opening 32 corresponding to the auxiliary electrode 22.

Specifically, the second openings 32 are distributed in a grid shape along with the auxiliary electrode 22.

Step S3, referring to FIG. 3, an OLED light emitting layer 40 covering the entire surface is formed on the auxiliary electrode 22, the pixel defining layer 30 and the plurality of anodes 21.

Specifically, the step S3 specifically includes:

Step S31, forming a hole injection layer 401 covering the entire surface on the auxiliary electrode 22, the pixel defining layer 30 and the plurality of anodes 21;

Step S32, forming an entire surface covering hole transport layer 402 on the hole injection layer 401;

Step S33, forming a plurality of light-emitting function layers 403 corresponding to the plurality of anodes 21 on the hole transport layer 402, respectively;

Step S34, forming an electron transport layer 404 covering the entire surface on the hole transport layer 402 and the light-emitting functional layer 403, the hole injection layer 401, the hole transport layer 402, the light-emitting functional layer 403, and the electron transport layer 404 together The OLED light-emitting layer 40.

Specifically, the OLED light-emitting layer 40 is prepared by evaporation or ink-jet printing (Ink-Jet print) process.

Preferably, the electron transport layer 404 is formed by an evaporation process in the step S34.

Step S4, referring to FIGS. 4 and 5, UV light is applied to the OLED light-emitting layer 40.

Preferably, in the step S4, the OLED light-emitting layer 40 is subjected to UV irradiation, wherein a low-pressure mercury lamp is used for UV irradiation, the wavelength of the UV irradiation is 250-260 nm, the illuminance is 25-30 mW/cm ² , and the UV irradiation The duration is greater than or equal to 600 seconds. By setting the wavelength, illuminance and process duration, the UV light effect can be ensured, the current conductivity of the electron transport material in the OLED light-emitting layer 40 can be effectively improved, and the gap between the auxiliary electrode and the cathode can be eliminated. Conduction barriers enhance the voltage drop improvement effect.

Specifically, as shown in Figure 9 and Figure 10, Figures 9 and 10 respectively perform UV light irradiation treatment on the two electron transport materials ET1 and ET2, and measure the current of the electron transport materials ET1 and ET2 before and after the UV light irradiation treatment -Voltage curve (IV Curve), which can be determined according to the current-voltage curve in Figure 9 and Figure 10. After UV treatment, the current value of the electron transport materials ET1 and ET2 at the same voltage increases significantly, so that the UV can be determined The light irradiation treatment can greatly improve the current conductivity of the electron transport material. According to this, the electron transport material in the OLED light-emitting layer 40, namely the electron transport layer 404, can pass the current under the same voltage after the UV irradiation of the present invention is passed. The value is significantly improved, that is, the present invention can greatly improve the current conductivity of the electron transport material by applying UV light to the OLED light-emitting layer 40 in the present invention.

Specifically, as shown in FIG. 4, in the first embodiment of the present invention, when the OLED light-emitting layer 40 is subjected to UV irradiation in the step S4, the entire surface of the OLED light-emitting layer 40 is subjected to UV irradiation, thereby improving The electron transport material in the OLED light-emitting layer 40, that is, the current conductivity of the electron transport layer 404, eliminates the conduction barrier between the auxiliary electrode and the cathode, and improves the voltage drop improvement effect.

Further, as shown in FIG. 5, different from the first embodiment of the present invention, in the second embodiment of the present invention, when the OLED light-emitting layer 40 is irradiated with UV light in the step S4, only The OLED light-emitting layer 40 in the two openings is irradiated with UV light, and the OLED light-emitting layer 40 outside the second opening 32 is not irradiated with UV light, which can improve the electron transport material in the OLED light-emitting layer 40 located in the second opening, that is, electron transport. The current conductivity of the layer 404 eliminates the conduction barrier between the auxiliary electrode and the cathode, improves the voltage drop improvement effect, and does not affect the working characteristics of the OLED light-emitting layer 40 outside the second opening 32, ensuring the OLED light-emitting layer 40 Work stability.

Step S5, referring to FIG. 5, a cathode 50 distributed over the entire surface is formed on the OLED light-emitting layer 40.

Specifically, in some embodiments of the present invention, the material of the cathode 50 is metal, preferably one or a combination of one or more of silver, aluminum and copper. Of course, this is not a limitation of the present application. In an embodiment, the cathode 50 may also be a transparent oxide, preferably indium tin oxide.

Specifically, by fabricating the auxiliary electrode 22 under the cathode 50, the sheet resistance of the cathode 50 can be reduced, and the problem of uneven brightness caused by voltage drop (IR drop) can be reduced. The OLED light-emitting layer 40 can be illuminated by UV to improve the electron transport material. The current continuity of this ensures the conduction effect between the cathode 50 and the auxiliary electrode 22.

Further, referring to FIG. 6, the manufacturing method of the OLED display panel further includes step S6, forming a packaging cover 60 on the cathode 50 to protect the OLED device through the packaging of the packaging cover 60.

In addition, the present invention also provides an OLED display panel, which is manufactured using the above-mentioned manufacturing method of the OLED display panel.

In summary, the present invention provides a method for manufacturing an OLED display panel, including the following steps: step S1, providing a base substrate, and forming a plurality of anodes arranged in an array on the base substrate The auxiliary electrode in the interval area of the anode; step S2, forming a pixel definition layer on the base substrate, the plurality of anodes, and the auxiliary electrode, and forming a plurality of second electrodes on the pixel definition layer respectively corresponding to the plurality of anodes. An opening and a second opening corresponding to the auxiliary electrode; step S3, forming an OLED light-emitting layer covering the entire surface on the auxiliary electrode, the pixel definition layer, and a plurality of anodes; step S4, performing UV on the OLED light-emitting layer Illumination; Step S5, forming cathodes distributed across the entire surface of the OLED light-emitting layer, UV light treatment can improve the current conductivity of the electron transport material in the OLED light-emitting layer, eliminate the barriers to conduction between the auxiliary electrode and the cathode, and improve Voltage drop improvement effect. The present invention also provides an OLED display panel, which can improve the current conductivity of the electron transport layer, eliminate the conduction barrier between the auxiliary electrode and the cathode, and improve the voltage drop improvement effect.

As mentioned above, for those of ordinary skill in the art, various other corresponding changes and modifications can be made according to the technical solutions and technical ideas of the present invention, and all these changes and modifications shall fall within the protection scope of the claims of the present invention. .

Claims

An OLED display panel manufacturing method includes the following steps:

Step S1: Provide a base substrate, on which a plurality of anodes arranged in an array and an auxiliary electrode located in a spacing area of the plurality of anodes are formed;

Step S2. A pixel defining layer is formed on the base substrate, a plurality of anodes and auxiliary electrodes, and a plurality of first openings corresponding to the plurality of anodes and a plurality of first openings corresponding to the auxiliary electrodes are formed on the pixel defining layer. Second opening

Step S3, forming an OLED light emitting layer covering the entire surface on the auxiliary electrode, the pixel defining layer and the multiple anodes;

Step S4, applying UV light to the OLED light-emitting layer;

Step S5, forming cathodes distributed over the entire surface of the OLED light-emitting layer.
8. The method for manufacturing an OLED display panel according to claim 1, wherein when the OLED light-emitting layer is subjected to UV irradiation in step S4, only the OLED light-emitting layer located in the second opening is subjected to UV irradiation.
The method for manufacturing an OLED display panel according to claim 1, wherein in step S4, the OLED light-emitting layer is subjected to UV irradiation, wherein a low-pressure mercury lamp is used for UV irradiation, and the wavelength of the UV irradiation is 250~260nm , Illumination 25~30 mW/cm 2 , and the duration of UV light is greater than or equal to 600 seconds.
The method for manufacturing an OLED display panel according to claim 1, wherein said step S3 specifically includes:

Step S31, forming a hole injection layer covering the entire surface on the auxiliary electrode, the pixel defining layer and the multiple anodes;

Step S32, forming an entire surface covering hole transport layer on the hole injection layer;

Step S33, forming a plurality of light-emitting function layers corresponding to the plurality of anodes on the hole transport layer;

Step S34, forming an electron transport layer covering the entire surface on the hole transport layer and the light emitting function layer, and the hole injection layer, the hole transport layer, the light emitting function layer and the electron transport layer together constitute the OLED light emitting layer.
8. The method for manufacturing an OLED display panel according to claim 4, wherein the electron transport layer is formed by an evaporation process in the step S34.
8. The method of manufacturing an OLED display panel according to claim 1, wherein one of the anode and the cathode is made of transparent oxide, and the other is made of metal.
8. The manufacturing method of the OLED display panel of claim 1, wherein the material of the auxiliary electrode is a transparent oxide.
8. The manufacturing method of the OLED display panel according to claim 1, wherein the material of the auxiliary electrode is metal.
8. The manufacturing method of the OLED display panel of claim 1, wherein the auxiliary electrodes are distributed in a grid pattern.
An OLED display panel manufactured by using the manufacturing method of the OLED display panel according to claim 1.