KR20020087714A - Organic Light Emitting Diodes(OLEDs) with Guard Ring - Google Patents

Abstract

PURPOSE: A thin film organic electroluminescence display device is provided to achieve improved luminance and optical characteristics of organic electroluminescence display device. CONSTITUTION: An organic electroluminescence display device comprises a transparent electrode(3), a hole injection layer(4), a hole transport layer(6), a luminescence layer(5), an electron transport layer, an electron injection layer, a metal electrode and a guard ring(1). The guard ring is made of Al having a reflectivity of 60 to 85% or Ag having a reflectivity of 95% deposited into the thickness of 1200 angstrom, at the four side surfaces of a glass substrate(2), through a vacuum evaporation method.

Description

Thin Film Organic Light Emitting Diodes with Guard Rings {Organic Light Emitting Diodes (OLEDs) with Guard Ring}

The present invention relates to an organic light emitting display device or display device manufactured using a guard ring of an organic light emitting display device used in data display and image processing and other fields.

The organic electroluminescent device is composed of (1) monolayer hole transport layer / monolayer light emitting layer, (2) monolayer hole injection layer / monolayer hole transport layer / monolayer light emitting layer between anode and cathode electrode on glass substrate, (3) Molecular hole transport layer / Molecular light emitting layer / Molecular electron transport layer, (4) Molecular hole injection layer / Single molecule hole transport layer / Single molecule light emitting layer / Single molecule electron transport layer / Single molecule electron injection layer, (5) Polymer hole transport layer / Polymer Light emitting layer, (6) It can be divided into the form containing a polymer hole injection layer / polymer hole transport layer / polymer light emitting layer / polymer electron transport layer.

Since the conventional organic light emitting diode uses glass as a substrate, the side loss of light emitted toward the side of the thick glass substrate is inevitably generated compared to the organic thin film, and thus the luminance, which is an important characteristic of the organic light emitting diode, tends to be lowered. There are many things that need to be improved.

Accordingly, it is an object of the present invention to provide a thin film organic electroluminescent device whose luminance can be improved.

FIG. 1 is a diagram schematically illustrating a structure of a general thin film organic light emitting diode having no guard ring.

2 is a view schematically showing the structure of a thin film organic light emitting diode incorporating a guard ring of the present invention.

3 is a view schematically showing the side loss of the light in the organic light emitting device when there is no guard ring.

4 is a diagram schematically illustrating the contribution of light emission by side reflection of light in an organic light emitting diode in the presence of a guard ring.

<Description of the symbols for the main parts of the drawings>

1: guard ring 2: glass substrate

3: ITO transparent electrode 4: hole transport layer

5: light emitting layer 6: electron transport layer

7: cathode electrode

Recently, attention has been focused on organic electroluminescent devices in data display, image processing and other fields. The organic electroluminescent device puts an electroluminescent material between an anode and a cathode, and emits light having a wavelength and an intensity characteristic of the material when a voltage is applied. In this method, holes are injected from the anode and electrons are injected into the light emitting material of the light emitting layer when the voltage is applied. The emitted light has a spectrum almost identical to the inherent fluorescence spectrum of the electroluminescent material.

The fabricated organic electroluminescent device, since the thickness of the glass used as a substrate, there is a problem that out becomes the critical angle of the air and the glass emits light in more than ¹⁹ light spreads laterally causing decrease in luminance (p. A. Burrows (PE Burrows et al., IEEE Tansactions on Electron Devices, Vol. 44, No. 8 (1997). Therefore, it is desirable to introduce a guard ring on all sides of the glass substrate so that the lossy light is trapped through the side to be emitted to the front surface of the glass to greatly improve the brightness of the organic light emitting display device. .

Hereinafter, the present invention will be described in detail.

In order to achieve the above object, the material of the guard ring used in the present invention includes aluminum (Al) having a reflectance of 60% to 85% or silver (Ag) having a reflectance of 95%, on all sides of the glass substrate by a vacuum deposition method. It is produced by depositing at 1200Å thickness. The light reflected by the guard ring thus manufactured increases the luminance, thereby providing an organic light emitting display device having an improved image quality for viewing information under bright ambient light conditions.

Preferred materials that can be used as guard rings in exemplary embodiments of the present invention include, in particular, silver (Ag), aluminum (Al) or any other material with good reflectivity that can be used as guard rings on the side of the glass substrate. Although not limited to the thickness range recited herein, the thickness of the guard ring includes any thickness sufficient to sufficiently reflect the light emitted by the luminescent material.

The organic electroluminescent device of the present invention has an advantage that it can be used in an organic electroluminescent device made of a polymeric material spin-coated as a whole, or an organic electroluminescent device made of a vacuum organic molecular organic material.

It also has the advantage that the device can be applied to organic light emitting devices using SOLED, single OLED, TOLED, IOLED or other design variations.

Thus, it is believed that the "guard ring" improves to have a brightness that is at least 10%, generally about 30-50% or more higher than similar devices without such additional processes.

According to the method of manufacturing a polymer organic light emitting device by spin coating with a guard ring or a single molecule organic light emitting device by vacuum deposition, the light emission characteristics of the organic light emitting device are not only improved, but light of side loss is also improved. By contributing to the light emission, it can be widely used in not only organic light emitting devices but also photodiodes, industrial LEDs, solar cells, and the like.

Claims (7)

An organic electroluminescent device comprising an anode transparent electrode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer, a metal electrode. 2. An organic electroluminescent device comprising a guard ring in an organic electroluminescent device comprising an anode transparent electrode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer, a metal electrode. 3. The method of claim 2, The material of the guard ring is an organic light emitting device, characterized in that the use of a material having a high reflectance such as silver (Ag), aluminum (Al). 4. The method of claim 2, An organic light emitting display device, characterized in that the guard ring is introduced to the side surface of the glass substrate. 5. The process of claim 2, Process of forming silver (Ag) and aluminum (Al) by vacuum evaporation or sputtering during the formation of guard rings. 6. The method of claim 5, wherein It is characterized by including both the thickness of silver (Ag) and aluminum (Al) when manufacturing the guard ring, and the thickness of the guard ring to the extent that can sufficiently reflect the light emitted by the light emitting material outside the cited thickness range. An organic electroluminescent device. 7. An optical device such as a photodiode, an industrial LED, and a solar cell, in which a guard ring is used as well as an organic light emitting device.