KR102648412B1 - Organic Light Emitting Diode Display Device - Google Patents

Abstract

The present invention was developed to prevent the above problems, and relates to an organic light emitting display device that can improve the efficiency and lifespan of an organic light emitting device by minimizing the occurrence of outgassing while having the effect of using a black bank. In the organic light emitting display device, a bank insulating film including an opening exposing the first electrode is formed on a substrate in a double layer of a black bank layer and a transparent bank layer.

Description

Organic Light Emitting Diode Display Device

The present invention relates to an organic light emitting display device, and more particularly to an organic light emitting display device including a bank layer that has excellent light leak prevention effect and can minimize outgassing.

Video display devices, which display various information on a screen, are a core technology of the information and communication era and are developing into thinner, lighter, more portable, and higher performance. Accordingly, organic light emitting display devices, which display images by controlling the amount of light emitted from the organic light emitting layer, are receiving attention as flat panel displays that can reduce the weight and volume, which are disadvantages of cathode ray tubes (CRTs). The organic light emitting element of the organic light emitting display device is a self-luminous element using a thin light emitting layer between electrodes and has the advantage of being able to be made into a thin film like paper.

In an active matrix organic light emitting display device, pixels composed of three color (R, G, B) sub-pixels are arranged in a matrix to display an image. Each sub-pixel includes an organic light emitting (OELD) cell and a cell driver that independently drives the light emitting cell.

The light-emitting cell includes a first electrode connected to the cell driver, a bank insulating film with an opening exposing the first electrode, an organic layer including a light-emitting layer located on top of the first electrode, and a second electrode formed on the organic layer. The first electrode contacts the organic layer only on the opening defined by the bank insulating film, and as the organic layer located in the opening contributes to light emission, the light emitting cell area is defined by the bank insulating film. Conventionally, organic light emitting display devices were equipped with a black matrix to prevent light leakage, but research is being actively conducted on organic light emitting display devices using black banks, which are more advantageous for expanding the viewing angle, preventing light leakage, and realizing high brightness.

Organic light emitting display devices using black banks have a superior ability to prevent light leakage compared to organic light emitting display devices using black matrices, and since the material itself is black, it can replace the role of a polarizer attached to the surface of an organic light emitting display device. Accordingly, an organic light emitting display device using a black bank has the advantage of being able to achieve high luminance because there is no decrease in transmittance due to a polarizer.

However, due to the nature of the material, black banks have a higher outgassing rate than transparent banks. Accordingly, when black banks are applied to organic light emitting display devices, the efficiency and lifespan of the organic light emitting device are reduced due to outgassing. did.

The present invention was developed to prevent the above problems, and aims to provide an organic light emitting display device that has the effect of using a black bank and can improve the efficiency and lifespan of the organic light emitting device by minimizing the occurrence of outgassing. Make it an assignment.

In order to solve the above problem, the organic light emitting display device according to the present invention forms a double bank insulating film including an opening exposing the first electrode on the substrate as a black bank layer and a transparent bank layer.

The transparent bank layer is formed to be located directly on top of the black bank layer. In this case, the transparent bank layer may be formed to completely cover the black bank layer.

A spacer is located on the bank insulating film. Additionally, an organic layer including a light-emitting layer and a second electrode are deposited on the entire surface of the substrate including the bank insulating layer and the spacer.

The black bank layer is made of at least one of black resin, graphite powder, gravure ink, black spray, and black enamel.

The organic light emitting display device according to the present invention reduces outgassing that occurs when forming a black bank by forming a bank insulating film having a double-stacked structure of a black bank and a transparent bank, and reduces outgassing that occurs when heat treating the black bank. The generation of impurities can also be reduced.

In particular, in the organic light emitting display device according to the present invention, the transparent bank 124b is located in the area in direct contact with the organic layer 118 to prevent the efficiency of the organic light emitting device (OLED) from being reduced due to outgassing and impurities. In addition, since the black bank 124a is located below the transparent bank 124b, it is possible to prevent light leakage and implement a high-brightness organic light emitting display device.

1 is a schematic diagram for explaining an organic light emitting display device according to the present invention.
Figure 2 is a cross-sectional view for explaining the schematic structure of each pixel provided in the display panel according to the present invention.
Figure 3 is a cross-sectional view of an organic light emitting display device according to the present invention including an upper substrate.
Figure 4 is a cross-sectional view of an organic light emitting display device according to the present invention in which the black bank layer completely covers the black bank layer.
FIG. 5 is a graph showing the luminance maintenance rate of a blue organic light emitting device (OLED) used in an organic light emitting display device when using a black bank and when using a transparent bank.
6A to 6F are cross-sectional views for explaining a method of manufacturing an organic light emitting display device according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. Like reference numerals refer to substantially the same elements throughout the specification. In the following description, if it is determined that a detailed description of technology or configuration related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Additionally, the component names used in the following description were selected in consideration of the ease of writing specifications and may be different from the component names of the actual product.

The shape, size, ratio, angle, number, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative and are not limited to the matters disclosed in the present invention.

When an element or layer is referred to as “on” or “on” another element, it includes not only the case directly on the other element layer but also the case where another layer or other element is interposed. On the other hand, when an element or layer is referred to as “directly in contact with” or “directly positioned” on another element, it indicates that there is no intervening other element or layer.

1 is a schematic diagram for explaining an organic light emitting display device according to the present invention.

As shown in FIG. 1, the organic light emitting display device according to the present invention includes a display panel including a plurality of pixels located in an area defined by a plurality of gate lines GL and data lines DL crossing each other. 5), a gate driver 6 driving a plurality of gate lines GL, a data driver 7 driving a plurality of data lines DL, aligning image data input from the outside, and controlling each pixel. It includes a timing controller 8 that outputs various signals that control the operation timing of the gate driver 6 and the data driver 7.

Each pixel of the display panel 5 is provided with an organic light emitting device (OLED) composed of an organic light emitting layer between an anode and a cathode, and a pixel circuit that independently drives the organic light emitting device (OLED).

The pixel circuit includes at least one switching transistor (TR1), at least one capacitor (Cst), and a driving transistor (TR2). In Figure 1, a pixel circuit having a 2T1C structure is shown, but the pixel circuit is not necessarily limited to this, and the pixel circuit may be configured in various ways, such as 3T1C, 4T2C, and 5T2C. The plurality of switching transistors TR1 charge the capacitor Cst with a data signal in response to the scan signal generated in each horizontal period. Then, the driving transistor TR2 drives the organic light emitting device (OLED) by supplying current to the organic light emitting device according to the data voltage charged in the capacitor Cst.

Figure 2 is a cross-sectional view for explaining the schematic structure of each pixel provided in the display panel according to the present invention.

As shown in FIG. 9, the driving transistor TR2 is formed on the substrate 100 and the buffer layer 101, and includes a semiconductor layer 104 including a source region 109a and a drain region 109b on both sides, and , a gate insulating film 106 covering the semiconductor layer 104, a gate electrode 102 located on top of the gate insulating film 106 corresponding to the semiconductor layer 104, and a substrate including the gate electrode 102 ( 100) and a first protective layer 112 including contact holes 113 exposing source/drain regions 109a and 109b located on both sides of the semiconductor layer 104, and through the contact holes It includes a source electrode 110 and a drain electrode 108 connected to the source/drain regions 109a and 109b.

A second protective layer 114 and an overcoat layer 116 are located on the driving transistor TR2. An organic light emitting device according to the present invention is located on the overcoat layer 116. The organic light emitting device includes a first electrode 1, a bank insulating film 124 having an opening 133 exposing the first electrode 1, a spacer 126 located on the bank insulating film 124, and It consists of an organic layer 118 including a light-emitting layer formed on the first electrode 1 exposed through the opening 133, and a second electrode 2 formed on the organic layer 118. The structure of the bank insulating film 124 will be described later.

The organic layer 118 may be composed of a single layer made of a light-emitting material, or may be composed of multiple layers of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer to increase luminous efficiency. At this time, the organic layer 118 may be formed on the entire surface of the substrate 100 including the first electrode 1, the bank insulating film 124, and the spacer 126.

The first protective film 112 includes a contact hole exposing the drain electrode 108, and the first electrode 1 is connected to the drain electrode 108 of the thin film transistor through the contact hole.

At this time, the substrate 100 is a flexible glass or polymer substrate, and the light emitting display panel according to the present invention can be manufactured as a flexible display or foldable display. In this case, the light emitting display panel according to the present invention includes at least one folding area within the display area, and the entire display area may be curved.

The organic light emitting display device according to the present invention may be configured so that one of red, green, and blue light emitting layers is located in each sub-pixel. Additionally, each sub-pixel may be configured to have a white light-emitting layer. When the white light emitting layer is configured to be located in each sub-pixel as described above, the organic light emitting display device according to the present invention preferably includes a color filter 135. The color filter 135 is located on the second protective film 114, and an overcoat layer 116 is formed to cover the color filter 135. The color filter 135 is used to convert white light emitted from the white light emitting layer into red, green, and blue. If red, green, and blue light emitting layers are located in each sub-pixel, the color filter 135 may be omitted. there is.

A barrier layer 130 is located on the second electrode 2. The barrier layer 130 has a structure in which at least one inorganic layer 127 and an organic layer 129 are alternately stacked.

Meanwhile, the organic light emitting display device according to the present invention may have a structure in which the lower substrate 100 and the upper substrate 200 are bonded as shown in FIG. 3. An auxiliary electrode 140 and a bus electrode 142 may be provided on the upper substrate 200, and the second electrode 2 and the auxiliary electrode 140 may be formed to contact each other on the spacer 126. The organic light emitting display device including the auxiliary electrode 140 and the bus electrode 142 has the effect of lowering the driving voltage of the organic light emitting display device by reducing the resistance of the second electrode 2.

The bank insulating layer 124 includes a black bank layer 124a and a transparent bank layer 124b. To explain this in more detail, the bank insulating film 124 of the present invention may have a dual structure of a black bank layer 124a and a transparent bank layer 124b.

At this time, the black bank layer 124a is preferably located on the lower layer to minimize contact with the organic layer 118, and the transparent bank layer 124b is preferably located directly on the black bank layer 124a. To this end, in the organic light emitting display device according to the present invention, as shown in FIG. 4, the transparent bank layer 124b may completely cover the black bank layer 124a to completely block contact between the black bank layer 124a and the organic layer 118. .

The black bank layer 124a is preferably formed of a material with a low dielectric constant. For example, the black bank layer 124a may be made of at least one of organic insulating materials such as black resin, graphite powder, paint ink, black spray, and black enamel.

FIG. 5 is a graph showing the luminance maintenance rate of a blue organic light emitting device (OLED) used in an organic light emitting display device when using a black bank and when using a transparent bank. In an organic light emitting display device using a black bank, it can be seen that the luminance maintenance rate of the blue organic light emitting device (OLED) decreases significantly during the same period of time. In other words, when black banks were applied, a problem occurred in which the lifespan of organic light emitting devices (OLEDs) was greatly reduced.

The reason is that the outgassing of the black bank is higher than that of the transparent bank, the barrier effect that blocks outgassing is also lower in the black bank than that of the transparent bank, and various impurities generated when heat treating the black bank are deposited on the first electrode (1). It is pointed out that the work function of the first electrode 1 increases by causing surface contamination.

The organic light emitting display device according to the present invention reduces outgassing that occurs when forming a black bank by forming a bank insulating film having a double-stacked structure of a black bank and a transparent bank, and reduces outgassing that occurs when heat treating the black bank. The generation of impurities can also be reduced.

In particular, in the organic light emitting display device according to the present invention, the transparent bank 124b is located in the area in direct contact with the organic layer 118 to prevent the efficiency of the organic light emitting device (OLED) from being reduced due to outgassing and impurities. In addition, since the black bank 124a is located below the transparent bank 124b, it is possible to prevent light leakage and implement a high-brightness organic light emitting display device.

Below, a method for manufacturing an organic light emitting display device according to the present invention will be described.

6A to 6F are schematic diagrams for explaining a method of manufacturing an organic light emitting display according to the present invention.

Referring to FIG. 6A, a buffer layer 101 is formed on the substrate 100, and a semiconductor layer 104 is formed on top of it. At this time, the buffer layer 101 and the semiconductor layer 104 are formed using a deposition method such as PECVD (Plasma Vapor Deposition). Then, the semiconductor layer 104 is patterned through a photolithography process and an etching process.

Referring to FIG. 6B, an inorganic insulating material is deposited on the substrate 100 including the semiconductor layer 104 through a deposition method such as PECVD to form the gate insulating film 106. A metal layer is deposited on the upper part through a method such as sputtering, and is patterned through a photolithography and etching process to form the gate electrode 102.

Using the gate electrode 102 as a mask, impurities are implanted into both sides of the semiconductor layer 104 through ion implantation or the like to form source and drain regions 109a and 109b.

Referring to FIG. 6C, the first protective film 1 is formed on the substrate 100 including the gate electrode 102 and the semiconductor layer 104 through a deposition method such as PECVD. A contact hole 113 is formed in the first protective film to expose the source/drain regions 109a and 109b through a photolithography process and an etching process.

Referring to FIG. 6D, metal layers forming the source electrode 110 and the drain electrode 108 are deposited through a method such as sputtering. Molybdenum (Mo), molybdenum tungsten (MoW), copper (Cu), etc. are used as source/drain metal layers. This source/drain metal layer is patterned through a photolithography process and an etching process to form a source/drain electrode pattern including the source electrode 110 and the drain electrode 108. Next, a second protective film 114 including a contact hole 122 is deposited on the first protective film 112 including the source electrode 110 and the drain electrode 108. At this time, the second protective film 114 may be formed of an organic insulating material such as acrylic through a method such as spin coating or spinless coating.

When the organic light emitting display device according to the present invention is formed using a white organic light emitting element, a color filter 135 may be further formed on the second protective film 114. At this time, an overcoat layer 116 is deposited on the color filter 135, and a contact hole 122 exposing the drain electrode 108 is formed in the overcoat layer 116 through a photolithography process and an etching process.

Referring to FIG. 6E, the first electrode 1 is formed on the overcoat layer 116.

Specifically, the first electrode 116 may be formed on the second protective film 114 using an opaque conductive material such as aluminum (Al) or a transparent conductive material such as ITO using a deposition method such as sputtering. The first electrode 1 is connected to the drain electrode 108 of the thin film transistor through a contact hole 122.

A bank insulating film 124 including an opening 133 is formed on the substrate 100 on which the first electrode 1 is formed. At this time, the bank insulating film includes a black bank layer 124a and a transparent bank layer 124b. The black bank layer 124b is made of at least one of a photosensitive organic insulating material, for example, black resin, graphite powder, gravure ink, black spray, and black enamel. The transparent bank layer 124b is also formed by applying a photosensitive organic insulating material to the entire surface and then patterning it.

In addition, the same photosensitive organic insulating material can be applied on the transparent bank layer 124b and then patterned to further form the spacer 126. At this time, the spacer 126 can be formed simultaneously with the transparent bank layer 124b by applying a photosensitive organic insulating material to the entire surface and then patterning the transparent bank layer 124b.

As shown in FIG. 6F, the organic layer 126 and the second electrode 128 are sequentially deposited on the substrate 100 on which the bank insulating film 124 including the opening 133 is formed. Specifically, an organic layer 118 including an electron injection layer (EIL), an electron transport layer (ETL), a light emitting layer, a hole transport layer (HTL), and a hole injection layer (HIL) is formed on the first electrode 116 using a thermal evaporation method or sputtering. It is formed by a method or a combination thereof.

Thereafter, the second electrode 2 is formed on the substrate 100 on which the organic layer 118 is formed. The second electrode 2 may be formed in at least a one-layer structure using a transparent conductive material or a metal material in the same manner as the organic layer 118, or may be formed in a multi-layer structure using a transparent conductive material and a metal material.

A barrier layer 130 is formed on the second electrode 2. The barrier layer 130 has a structure in which at least one inorganic layer 127 and an organic layer 129 are alternately stacked, and may be formed by a method such as atomic layer deposition (ALD).

An upper substrate (not shown) may be further included on top of the barrier layer 130, but the upper substrate may not be provided.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of.

100: substrate 101: buffer
102: gate electrode 104: semiconductor layer
106: gate insulating film 108: drain electrode
109a, 109b: source, drain area 110: source electrode
112: 1st shield 114: 2nd shield
116: Overcoat layer 135 Color filter layer
1: first electrode 2: second electrode
122: contact hole 133: opening
126: spacer 130: barrier layer
124a: Black bank layer 124b: Transparent bank layer
127: inorganic membrane 129: organic membrane

Claims (8)

A transistor located on the lower substrate,
A protective film located on the transistor,
A color filter located on the protective film,
an overcoat layer directly covering the color filter,
a first electrode connected to one electrode of the transistor through a contact hole formed in the overcoat layer and the protective film;
a bank insulating film including an opening exposing the first electrode on the lower substrate provided with the first electrode;
A spacer located on the bank insulating film,
an organic layer including a light-emitting layer positioned on the first electrode exposed through the opening;
It includes a second electrode located on the entire surface of the lower substrate including the bank insulating film and the organic layer,
The bank insulating film includes a black bank layer and a transparent bank layer located directly on top of the black bank layer,
The transparent bank layer and the spacer are made of the same material,
The distance between the upper surface of the lower substrate and the upper surface of the transparent bank layer is smaller than the distance between the upper surface of the lower substrate and the upper surface of the spacer,
The light emitting layer is a white light emitting layer,
The color filter is positioned below the first electrode in the opening with the overcoat layer interposed therebetween. delete According to claim 1,
The transparent bank layer is positioned to completely cover the black bank layer. delete According to claim 1,
The black bank layer is an organic light emitting display device made of at least one of black resin, graphite powder, gravure ink, black spray, and black enamel. According to claim 1,
The organic layer is located on the front surface of the lower substrate including the transparent bank layer and the first electrode exposed through the opening. According to claim 6,
The transparent bank layer completely covers the black bank layer,
An organic light emitting display device wherein the organic layer is in direct contact with the transparent bank layer and the spacer. According to claim 1,
an upper substrate facing the lower substrate,
a bus electrode located on the upper substrate,
Further comprising an auxiliary electrode located on the bus electrode,
The auxiliary electrode includes a protrusion that protrudes toward the lower substrate in an area overlapping with the bus electrode,
The protrusion is in direct contact with the second electrode.

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