KR20000046140A - Organic electroluminescent display panel and method therefor - Google Patents

Abstract

An organic EL display panel for increasing luminous efficiency and a method of manufacturing the same, comprising: forming a first electrode in a strip form on a substrate, coating a photoresist layer in which a silver compound is dispersed on the substrate, and then coating the coated photoresist layer After prebaking, exposure and development, the photoresist is heat treated to cure, and the silver compound in the photoresist is reduced to form a silver reflector on the surface to form a partition having a silver reflector between the first electrode strips. Subsequently, by forming one or more organic layers on the entire surface of the substrate having partitions, and forming an electrode layer on the entire surface of the organic layer to form a second electrode in the form of a strip insulated from each other in a direction orthogonal to the first electrodes by a step caused by the partitions. When emitting light, it minimizes the amount of light transmitted through the partition wall to increase the light emitting efficiency. In addition, since the conventional bulkhead processing method is maintained and the silver reflector is formed, the process is simple and the silver compound is not expensive. Therefore, the luminous efficiency can be maximized at a low price, and the photoresist is coated with a metal because the film is coated with a metal. By blocking the solvent or the oxygen or moisture coming from the outside to prevent the shrinkage of the organic film to increase the life of the device.

Description

Organic EL display panel and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display panel, and more particularly, to an organic EL display panel for increasing luminous efficiency and a method of manufacturing the same.

Recently, the technology of an organic EL device, also called an organic light emitting diode (LED), is rapidly developing, and several prototypes have already been announced.

The organic EL device is a device using a principle that electrons and holes injected through an electrode are moved to a light emitting region, electrons and holes are combined to form an exciton in an energy excited state, and then emit light while falling to a ground state.

This organic EL device is very thin, can be addressed in a matrix form, and can be driven at a low voltage of 15V or less.

In addition, the organic EL device can be formed on a flexible transparent substrate such as a wide viewing angle and plastic, and thus is suitable for a next-generation flat panel display (FPD), and also has a wide viewing angle and high contrast due to self-luminous. Because of its excellent properties such as high speed response, it can be used as a pixel of graphic, television image display or surface light source.

In addition, compared to a well-known liquid crystal display (LCD), a backlight is not required, and thus power consumption is low.

The pixel formation method of the organic EL device having such an advantage is shown in FIG.

That is, as shown in FIG. 1, an anode 2 having a stripe shape (hereinafter, referred to as a second electrode) is formed on the transparent substrate 1 by chemical etching of indium tin oxide (ITO), which is a transparent electrode. A first electrode), and an organic EL layer 4 coated thereon by a vacuum deposition method, and then a cathode 3 (hereinafter referred to as a second) in a direction perpendicular to the band-shaped first electrode 2 An electrode) to fabricate the device.

In addition, partition walls were used to form finer second electrode strips as shown in FIGS. 2A to 2D.

First, as shown in FIG. 2A, a stripe of the first electrode 2 having a predetermined interval is formed on the transparent substrate 1, and as shown in FIG. 2B, the second electrode is formed on the first electrode 2. In order to electrically insulate the bands, partition walls 5 having a predetermined interval are formed in advance.

Then, by forming the organic EL layer 4 on the first electrode 2 including the partition wall 5 as shown in FIG. 2C, and forming the second electrode 3 thereon as shown in FIG. 2D. An organic EL display element is produced.

At this time, the organic EL layer 4 and the second electrode 3 are electrically insulated between the pixels by the partition wall 5.

However, the luminous efficiency was not so good in the organic electroluminescent display panel produced in this way.

In general, the organic EL display device is a device that emits light when the electrons and holes are combined to form an exciton, which is an energy excited state, and then fall to a ground state, and the effective exciton that emits light is a singlet-single exciton. (singlet-singlet exciton).

In fact, only singlet-single excitons are excitons used to emit light, and since the probability is 1/4 in combination, 25% is the highest when referring to luminous efficiency in organic EL display elements.

However, this 25% is actually lost through various paths in the device and only about 5% of the light is emitted to the front emission.

In addition, when driving an organic EL display panel, the device shrinks due to the influence of external or internal factors such as oxygen or moisture in the air and solvent remaining in the partition wall as the time elapses, thereby reducing the lifetime. do.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and an organic EL display panel and a light emitting device for increasing the efficiency of light emission in a mono-, multi- or full-color flat panel display panel and its The purpose is to provide a manufacturing method.

1 is a view showing a general organic EL display panel

2A to 2D are cross-sectional views showing a manufacturing process of an organic EL display panel according to the prior art.

Fig. 3 is a structural sectional view showing the structure of an organic EL display panel according to the present invention.

Explanation of symbols for main parts of the drawings

1 substrate 2 first electrode

3: second electrode 4: organic EL layer

5: bulkhead

A feature of the organic EL display panel according to the present invention is a first electrode formed in a strip form on a substrate, a partition formed between the first electrode strips, a partition having a silver reflector on the surface, and a 1 formed on the front surface of the substrate having a partition. An organic layer of more than a layer and an electrode layer are formed on the entire surface of the organic layer, and the second electrode in a strip form is formed to be insulated from each other in a direction orthogonal to the first electrode by a step by a partition.

Another feature of the present invention is to form the partition wall as a first partition having a reflector on the surface and a second partition having no reflector on the surface.

Features of the method for manufacturing an organic EL display panel according to the present invention include the steps of forming a first electrode in a strip form on a substrate, forming a partition wall having a silver reflector on the surface between the first electrode strips, and a substrate having a partition wall. Forming at least one organic layer on the front surface, and forming an electrode layer on the front surface of the organic layer to form a second electrode in a strip form insulated from each other in a direction orthogonal to the first electrode by a step by a partition wall. .

Other features of the present invention include a first step of coating a photoresist layer in which a silver compound is dispersed on a substrate, a second step of prebake, exposing and developing the coated photoresist layer, and a photoresist. And a fourth step of hardening by heat treatment and a fourth step of reducing the silver compound in the photoresist to form a silver reflector on the surface.

Another feature of the present invention is that the ratio of adding silver compound in the partition wall is 0.01-50 wt%.

Hereinafter, an organic EL display panel and a method of manufacturing the same according to the present invention having the above characteristics will be described with reference to the accompanying drawings.

First, the concept of the present invention by using a prior art to artificially create a mirror (mirror) on the partition wall to prevent the light emitted from the device is transmitted or absorbed through the partition wall to induce the light to the front to increase the luminous efficiency This is to increase the efficiency regardless of the structure and material of the device.

That is, using a conventional process of making a bulkhead as it is, adding a silver (Ag) compound to the photoresist used only as a material of the bulkhead, using a reducing agent to make silver ions, and then a slight heat treatment in a weak alkali solution This is a method of forming a silver reflector on the partition wall.

3 is a structural cross-sectional view showing the structure of an organic EL display panel according to the present invention. Referring to FIG. 3, the manufacturing process of the present invention will be described.

First embodiment

As shown in FIG. 3, first, a first electrode 2 in strip form is formed on the substrate 1 at regular intervals, and the substrate 1 on which the first electrode 2 is formed is cleaned.

Subsequently, the substrate 1 is subjected to HMDS treatment, followed by spin coating a positive photoresist having a silver compound dispersed therein.

At this time, the silver compound addition ratio in a partition shall be 0.01-50 wt%.

The coated photoresist is then prebaked and exposed to ultraviolet light.

Subsequently, the photoresist is immersed in Mono-chloro Benzene (MCB), developed, and then the photoresist is hard-baked and deep UV hardened to cure.

Subsequently, the silver compound in the photoresist is reduced to 2-amino-2-methyl-aceticacid to make silver ions (Ag ⁺ ), soaked in a weak alkali solution (weak ammonia water), and heated through a water bath to partition the partition wall. (5) A silver reflector of a thin film is formed on the surface.

After the silver reflecting mirror is formed, it is washed with distilled water and dried to form a partition 5 having a silver reflecting mirror between the strips of the first electrode 2.

Here, before forming the partition 5, a buffer layer (not shown) may be formed in advance, and then the partition 5 may be erected thereon.

If a negative photoresiet is used, a buffer layer should be used, so a reflector may be formed on the side of the buffer layer.

The process of making the reflector on the side of the buffer layer is made by dispersing the silver compound in the buffer layer material.

Here, since the first electrode is etched in hydrochloric acid or nitric acid, there is no fear of being etched in a reducing agent or a weak alkali solution, and there is no need to coat another protective film for protecting the first electrode, so that the process is simple and easy.

When the partition wall 5 is formed in this manner, one or more organic EL layers 4 are vacuum deposited on the entire surface of the substrate having the partition walls, and an electrode layer is formed on the entire organic EL layer 4, resulting in a step by the partition wall 5. An organic EL display panel is produced by forming the strip-shaped second electrodes 3 that are insulated from each other in a direction orthogonal to the first electrodes 2.

However, in the first embodiment, since silver metal is formed on the partition wall surface, there may be a possibility that a short circuit phenomenon may occur with the metals used as electrodes.

Second embodiment

In the second embodiment, as in the first embodiment, the substrate 1 on which the first electrode 2 is formed is cleaned, the substrate 1 is subjected to an HMDS treatment, and then a positive photoresist in which silver compounds are dispersed. Spin coating the positive photoresist.

Subsequently, a photoresist having no silver compound added thereon is coated once more to produce a two-layer structure.

In this way, the two-layer structure can prevent the short circuit of the electrodes.

Other fabrication processes are the same as in the first embodiment of the present invention, so detailed description thereof will be omitted.

The organic EL display panel and its manufacturing method according to the present invention have the following effects.

The present invention increases the luminous efficiency by minimizing the amount of light transmitted and absorbed into the partition wall by forming a reflector on the surface of the partition wall by adding a material capable of forming only a silver reflector in the conventional partition wall manufacturing method.

In addition, since the conventional partition process is maintained and the silver reflector is formed, the process is simple and the silver compound is inexpensive, thereby maximizing the luminous efficiency at a low price.

In addition, since the photoresist is coated with a metal, a solvent in the photoresist, oxygen or moisture coming in from the outside are blocked to prevent shrinkage of the organic layer, thereby increasing the life of the device.

Claims (14)

A first electrode formed in a strip shape on the substrate; Barrier ribs formed between the first electrode strips and having reflecting surfaces on surfaces thereof; At least one organic layer formed on an entire surface of the substrate having the partition walls; An organic EL display panel comprising an electrode layer formed over the organic layer and insulated from each other in a direction orthogonal to the first electrode by a step caused by the partition wall. The organic EL display panel according to claim 1, wherein the partition wall comprises a first partition wall having a reflector on the surface and a second partition wall not having a reflector on the surface. An organic EL display panel according to claim 1, wherein the barrier rib is formed on a buffer layer. The organic EL display panel according to claim 3, wherein a reflector is formed on a surface of the buffer layer. The organic EL display panel according to claim 1, wherein the reflector formed on the partition wall is made of silver. Forming a first electrode in the form of a strip on the substrate; Forming a partition having a silver reflector on a surface between the first electrode strips; Forming at least one organic layer on an entire surface of the substrate having the barrier ribs; Forming an electrode layer on the entire surface of the organic layer to form a second electrode having a strip shape insulated from each other in a direction orthogonal to the first electrode by a step by the partition wall; . The method of claim 6, wherein forming the partition wall Coating a photoresist layer in which a silver compound is dispersed on a substrate; Prebake, exposing and developing the coated photoresist layer; A third step of curing the photoresist by heat treatment; And a fourth step of reducing the silver compound in the photoresist to form a silver reflector on a surface thereof. 8. The method of manufacturing an organic EL display panel according to claim 7, wherein in the first step, a silver compound addition ratio in the partition wall is 0.01 to 50 wt%. 8. The method of claim 7, wherein the first step comprises cleaning the substrate and HMDS processing before forming a photoresist layer. 8. A method according to claim 7, wherein in the second step, the photoresist is immersed in mono-chlorobenzene (MCB) before development. 8. The method of claim 7, wherein the third step is hard-baking the photoresist and deep UV hardning to cure the organic EL display panel. 8. The method of claim 7, wherein the fourth step is Reducing the silver compound in the photoresist with 2-amino-2-methyl-aceticacid to make silver ions; And dipping the photoresist having the silver ions into a weak alkali solution and heating to form a silver reflector on the surface thereof. 8. The method of claim 7, further comprising, in the first step, coating the photoresist layer having no silver compound added thereon after coating the photoresist layer having the silver compound dispersed thereon. An organic EL display panel manufacturing method. 7. The method of manufacturing an organic EL display panel according to claim 6, wherein after forming the first electrode, a buffer layer having a silver reflector is formed on a side surface thereof.