KR20120019599A - Organic light emitting display device - Google Patents

Abstract

PURPOSE: An organic light emitting display device is provided to improve a banding property by reducing stress of an inorganic layer and an organic layer through a buffer layer on a flexible substrate. CONSTITUTION: An organic light emitting display device(210) includes a bottom electrode(210a), an organic light emitting layer(210b), and a top electrode(210c). The bottom electrode and the top electrode are arranged on a substrate(200) to face each other. The organic light emitting layer is formed between the bottom electrode and the top electrode. An inorganic layer(220) and an organic layer(230) are laminated on the organic light emitting device. One or more buffer layers(225) are laminated between the inorganic layer and the organic layer.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display device. Even when a large area flexible organic light emitting display device is manufactured, the banding characteristics can be improved by relieving stress of the films constituting the organic light emitting display device. The present invention relates to an organic light emitting display device.

Video display devices that implement a variety of information as screens are the core technologies of the information and telecommunications era, and are developing in a direction that is thinner, lighter, more portable, and high performance. BACKGROUND ART As a demand for a flexible display that can be bent in pursuit of space and convenience, an organic light emitting display device that controls the amount of light emitted from an organic light emitting layer as a flat panel display device has recently been in the spotlight.

The organic light emitting diode display includes an organic light emitting diode display device formed by sequentially stacking a lower electrode, a hole injection layer, a hole transport layer, an organic light emitting layer, an electron injection layer, an electron transport layer, and an upper electrode on a substrate, and the organic light emitting display device. A capping layer may be formed by capping and covering the capping layer.

An organic light emitting display device uses an electroluminescence phenomenon in which an electric field is formed at both ends of an organic light emitting layer and at an upper electrode, and emits light by binding energy when the electrons and holes are injected and transferred into the organic light emitting layer to be bonded to each other. After electrons and holes are paired in, it is emitted from the excited state to the ground state and emits light.

Hereinafter, a general organic light emitting diode display will be described in detail.

1 is a cross-sectional view of a general organic light emitting diode display, in which an organic layer and an inorganic layer are alternately stacked on a organic light emitting diode display to form a capping layer.

As shown in FIG. 1, a general organic light emitting display device includes a substrate 100; An organic light emitting diode display 110 including lower and upper electrodes 110a and 110c formed on the substrate 100 and facing each other and an organic light emitting layer 110b formed between the upper and lower electrodes 110c and 110a. ); The capping layer may be formed by alternately stacking the inorganic layer 120 and the organic layer 130 on the organic light emitting element 110.

In particular, when the substrate 100 is formed of a flexible plastic or metal material, a flexible organic light emitting display device that can be bent can be manufactured.

However, as the organic light emitting display device is manufactured in a large area, the degree of warpage of the substrate 100 increases, so that the upper and lower electrodes 110c and 110a and the inorganic stress generated in the substrate 100 have a multilayer structure. The films 120 are transferred to the films constituting the organic light emitting diode display device such as the film 120 and the organic film 130, and the films are structurally weak.

In particular, peeling and cracks are generated in the inorganic layer 120 and the organic layer 130 formed on the organic light emitting diode display 110, and oxygen or moisture flowing into the organic light emitting diode display 110 from outside. As a result, the organic light emitting display device 110 may be degraded.

The present invention is to solve the above problems, by forming a buffer layer on a large-area flexible substrate, to reduce the stress of the films constituting the organic light emitting display device even if the substrate is bent An object of the present invention is to provide an organic light emitting display device which prevents peeling and cracking of layers constituting the organic light emitting display device.

An organic light emitting display device according to a first embodiment of the present invention for achieving the above object, a substrate; An organic light emitting display element formed on the substrate and configured of a first electrode, a second electrode, and an organic light emitting layer; And a capping layer formed to cover the organic light emitting display device, and at least one buffer layer.

The buffer layer is selected from a polymer, an organic material including a monomer or an inorganic material including an oxide.

The buffer layer is selected from a metal material including silver (Ag), aluminum (Al), copper (Cu), magnesium (Mg), and calcium (Ca).

The buffer layer has a thickness of 500 kPa or less.

The capping layer includes an inorganic film and an organic film that are alternately stacked at least once.

The capping layer is a single inorganic film.

The capping layers are alternately stacked at least once and include first and second inorganic layers having different thicknesses.

In addition, an organic light emitting display device according to a second embodiment of the present invention for achieving the same object, the substrate; An organic light emitting display device including a lower electrode, an organic light emitting layer, a first upper electrode, a buffer layer, and a second upper electrode sequentially stacked on the substrate; And a capping layer formed to cover the organic light emitting display element.

The first upper electrode and the second upper electrode are formed of the same material.

The first upper electrode and the second upper electrode are formed of different materials.

As described above, in the organic light emitting diode display of the present invention, even when a flexible organic light emitting diode display is manufactured in a large area, the buffer layer formed on the substrate relieves stress of the lower electrode, the upper electrode, the inorganic layer, and the organic layer. As a result, banding characteristics of the organic light emitting diode display may be improved, and peeling and cracking of the inorganic layer and the organic layer may be prevented.

As a result, it is possible to completely block oxygen or moisture flowing into the organic light emitting display device from the outside, thereby preventing the performance of the organic light emitting display device from deteriorating.

1 is a cross-sectional view of a general organic light emitting display device.
2A is a cross-sectional view of an organic light emitting diode display according to a first exemplary embodiment of the present invention.
2B is a cross-sectional view of an organic light emitting diode display according to a second exemplary embodiment of the present invention.

In the organic light emitting diode display of the present invention, a buffer layer is formed on a large-area flexible substrate, so that the stress of the films constituting the organic light emitting diode display may be reduced even when the substrate is bent.

Hereinafter, an organic light emitting diode display according to an exemplary embodiment will be described in detail with reference to the accompanying drawings.

First Embodiment

2A is a cross-sectional view of an organic light emitting diode display according to a first exemplary embodiment of the present invention.

As shown in FIG. 2A, the organic light emitting diode display according to the first exemplary embodiment of the present invention includes a substrate 200; An organic light emitting diode display 210 including lower and upper electrodes 210a and 210c formed on the substrate 200 and facing each other, and an organic light emitting layer 210b formed between the upper and lower electrodes 210c and 210a. ); In addition, the inorganic layer 220 and the organic layer 230 are alternately stacked on the organic light emitting element 210, and at least one buffer layer 225 formed between the inorganic layer 220 and the organic layer 230. It includes a capping layer comprising a).

The substrate 200 is selected from a series of polymer materials including polyethyleneterephehalate (PET), polyethersulphone (PES), polyimide (PI), polyethylenenaphthelate (PEN), and the like. It is formed of a flexible material, such as selected plastics, or metals and metal foils including iron, iron alloys, aluminum and aluminum alloys, and the like.

Although not illustrated, the organic light emitting diode display 210 further includes an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer formed between the organic light emitting layer 210b, the lower electrode 210a, and the upper electrode 210c. It can be made, including. In addition, the thin film transistor formed at the intersection of the gate line and the data line formed on the substrate 200 and the lower electrode 210a are connected so that the lower electrode 210a can receive a voltage signal through the thin film transistor. have.

The lower electrode 210a is formed of a transparent conductive metal having a high work function such as indium-tin-oxide and indium-zinc-oxide, and the upper electrode 210c. The work function including silver aluminum (Al), calcium (Ca) and magnesium (Mo) is formed as one selected from the group of low conductive metals.

In addition, the capping layer includes an inorganic layer 220 and an organic layer 230 which are alternately stacked at least once, and prevents moisture permeation by blocking external air to the organic light emitting diode display 210 to protect and encapsulate. Function

In the drawing, only the capping layer is formed by alternately stacking the inorganic layer 220 and the organic layer 230, but the capping layer may be formed as a single inorganic layer, and the first and second inorganic layers having different thicknesses. The films may be formed by alternately stacking.

The inorganic layer 220 is selected from SiOx, SiNx, SiC, SiON, SiOC, SiONC, and aC (Amorphous Cabon), and the organic layer 230 is selected from an acrylate, an epoxy polymer, and an imide polymer. Is done.

In addition, the thickness of the organic layer 230 is thicker than the thickness of the inorganic layer 220 to reduce surface curvature caused by foreign matter generated in the inorganic layer 220, and the organic layer 230 may prevent light from outside. Blocking may improve transmittance of the OLED display.

However, when the organic light emitting diode display having the flexible substrate is manufactured in a large area as described above, the substrate 200 is bent and the stress generated in the substrate 200 is lowered, the upper electrodes 210a and 210c, and the inorganic layer. The layers are transferred to the layers constituting the organic light emitting display such as the organic layer 220 and the organic layer 230, so that the layers are structurally weak. In particular, the inorganic film 220 and the organic film 230 formed on the organic light emitting diode display 210 may be peeled off or cracks may occur, and thus, external oxygen may flow into the organic light emitting diode display 200. There is a problem that the performance of the organic light emitting display device 210 is deteriorated due to failure to completely block moisture.

Accordingly, the capping layer covering the organic light emitting diode display 210 includes at least one buffer layer 225 to alleviate stress generated in the substrate 200.

In the drawing, the buffer layer 225 is formed between the bottom inorganic layer 220 and the organic layer 230, but the present invention is not limited thereto. The buffer layer 225 may be formed of another layer of the inorganic layer 220 and the organic layer ( 230).

The thickness of the buffer layer 225 is preferably 500 μs or less, and the buffer layer 225 is an organic material including a polymer, a monomer, or the like, or silver (Ag), aluminum (Al), or copper (Cu). , A metal material containing magnesium (Mg), calcium (Ca) and the like or an inorganic material containing an oxide such as Al ₂ O ₃ , SiO _2, and the like. In addition, the buffer layer 225 may be formed of a mixed material of the organic material, the metal material, and the inorganic material.

Accordingly, banding of the organic light emitting display device may be performed by alleviating stress transmitted to the lower, upper electrodes 210a and 210c, the inorganic layer 220, and the organic layer 230 having a multilayer structure. ) The characteristics are improved.

Second Embodiment

2B is a cross-sectional view of an organic light emitting diode display according to a second exemplary embodiment of the present invention.

As shown in FIG. 2B, the organic light emitting diode display according to the second exemplary embodiment of the present invention includes a substrate 300; An organic light emitting display device including a lower electrode 310a, an organic emission layer 310b, a first upper electrode 310c, a buffer layer 325, and a second upper electrode 310d sequentially stacked on the substrate 300. 310; The capping layer is formed by alternately stacking the inorganic layer 320 and the organic layer 330 to cover the organic light emitting diode display 310.

In the drawing, only the capping layer is formed by alternately stacking the inorganic layer 320 and the organic layer 330, but the capping layer may be formed as a single inorganic layer, and the first and second inorganic layers having different thicknesses. The films may be formed by alternately stacking.

The first upper electrode 310c and the second upper electrode 310d are formed of one selected from a group of conductive metals having a low work function, such as aluminum (Al), calcium (Ca), and magnesium (Mo). The first upper electrode and the second upper electrode may be formed of the same material or different materials.

That is, in the second embodiment, even when the organic light emitting diode display is manufactured in a large area by forming a buffer layer 325 between the first upper electrode 310c and the second upper electrode 310d, the buffer layer 325 may not be formed. Bending of the organic light emitting display device may be performed by relieving stress transmitted to the lower electrode 310a, the first and second upper electrodes 310c and 310d, the inorganic layer 320, and the organic layer 330 having a multilayer structure. banding) characteristics are improved.

Accordingly, the organic light emitting diode display of the present invention forms a buffer layer on the flexible substrate to reduce the stress of the lower electrode, the upper electrode, the inorganic layer, and the organic layer, thereby making the organic light emitting diode display large. Even if manufactured, the buffer layer may relieve stress of the films forming the organic light emitting diode display, thereby improving banding characteristics of the organic light emitting diode display.

The buffer layer prevents peeling and cracking of the inorganic layer and the organic layer to completely block oxygen or moisture introduced into the organic light emitting display device, thereby preventing the performance of the organic light emitting display device from deteriorating. can do.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in Esau.

200: substrate 210: organic light emitting display element
210a: lower electrode 210b: organic light emitting layer
210c: upper electrode 220: inorganic film
225: absorber layer 230: organic film

Claims (10)

Board;
An organic light emitting display element formed on the substrate and configured of a first electrode, a second electrode, and an organic light emitting layer; And
And a capping layer formed to cover the organic light emitting diode display, the capping layer including at least one buffer layer. The method of claim 1,
And the buffer layer is selected from an organic material including a polymer, a monomer, or an inorganic material including an oxide. The method of claim 1,
The buffer layer is selected from a metal material including silver (Ag), aluminum (Al), copper (Cu), magnesium (Mg), and calcium (Ca). The method of claim 1,
And the buffer layer has a thickness of 500 mW or less. The method of claim 1,
And the capping layer includes an inorganic layer and an organic layer that are alternately stacked at least once. The method of claim 1,
And the capping layer is a single inorganic layer. The method of claim 1,
And the capping layers are alternately stacked at least once and include first and second inorganic layers having different thicknesses. Board;
An organic light emitting display device including a lower electrode, an organic light emitting layer, a first upper electrode, a buffer layer, and a second upper electrode sequentially stacked on the substrate; And
And a capping layer formed to cover the organic light emitting display element. The method of claim 8,
The first upper electrode and the second upper electrode are formed of the same material. The method of claim 8,
The first upper electrode and the second upper electrode are formed of different materials.

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