KR100916385B1 - A organic electroluminescence device - Google Patents

Abstract

The present invention relates to an OELD, and more particularly, in an OELD having an encapsulation cap attached to a substrate surface having an OEL layer to protect the OEL layer, by attaching an oxygen gas generator to the inside of the encapsulation cap, the inside of the device during use of the OELD. By maintaining oxygen pressure by filling oxygen gas, not only does it eliminate the short-circuit path, which is the cause of the progressive line death caused by the use of OELD, but also improves the brightness and the life of the device, thereby preventing the reliability of the device from being lowered. And it is possible to improve the yield and image quality of the OELD device.

Description

Organic electroluminescence display device {A organic electroluminescence device}

1 is a cross-sectional view of a conventional organic electroluminescent display device.

2 is a perspective view of a sealing cap of an organic electroluminescent display device according to an embodiment of the present invention.

3 is a schematic view of the oxygen gas generator in FIG.

4 is a perspective view of a sealing cap of an organic electroluminescent display device according to another embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

10: glass substrate 12: OEL layer

14: seal 20, 30: scan

22,32,52: Groove 24,34,54: Adhesive surface

26,36: absorbent 40: oxygen gas supply

42: chamber 44: oxygen gas generator

45: heating element 46: power supply

48: switching unit 50: glass cap

The present invention relates to an organic electroluminescence display device (hereinafter referred to as OELD), and more particularly, to an OELD that can be stably used for a long time by allowing a gas supply to the device.

Electroluminescence devices (hereinafter referred to as ELDs) began to be studied in the 1960s and began to be reviewed in earnest in display devices since Eastman Kodak, USA, published a paper on high brightness in 1987. . Subsequently, in 1993, Japan made a striking progress by generating three RGB colors simultaneously and displaying white light close to natural light. In addition, high brightness, low power consumption, and long lifetime of the device are realized, and ELD is expected to be greatly expected as a next-generation flat panel display replacing the liquid crystal display device.

ELD is also suitable for application to dot matrix displays of mobile phones and stereos, and ELD is evaluated to be superior to LCD in moving picture display on PC and TV.

Currently, ELD is being researched using not only glass as a substrate but also a polymer film (plastic), and even in current glass substrates, ELD can realize a plate thickness of about 2 mm. Implementation is possible. The ELD is attracting attention as a next-generation flat panel display because of its low power consumption, easy portability in terms of size and weight, and large screen size.

On the other hand, ELDs using electroluminescence phenomena that emit strong fluorescence include inorganic ELDs using inorganic phosphors such as ZnS and Mn as emission centers, and OELDs produced by dispersing an organic material or an organic material in a polymer matrix. The inorganic ELD is only suitable for natural colors because it can only operate in high electric fields of several tens of volts, and it is difficult to obtain various colors, while OELD emits almost all colors from blue to purple and is inferior to other devices in terms of luminous luminance. It has no good characteristics such as low voltage, low power consumption and high viewing angle.

In particular, the OELD is degraded by moisture and oxygen. To prevent this, an encapsulation cap including a polymer film, glass, stainless steel, or sus as a main material is maintained while maintaining a predetermined space on the substrate on which the organic light emitting layer is deposited. Overlapping encapsulation takes place. The encapsulation cap is equipped with a desiccant therein so as to reduce the influence of the gas generated in the organic EL layer inside the OELD and moisture and oxygen from the outside.

1 is a cross-sectional view of an OELD according to the prior art, which is an example of an OELD sealed with a Sus Can.

First, an OEL layer 12, which is a light emitting part, is formed in a display area of one surface of the glass substrate 10, and is formed at the side of the scan 20 having a recess 22 in the center of the OEL layer 12. The adhesive surface 24 is bonded to the substrate 10 by the actual 14, and the groove 22 is attached with a moisture absorbent 26 for removing moisture after assembly.

In more detail, the bonding method may be performed by applying an actual 14 to the adhesive surface 24 of the sus 20 in a nitrogen gas atmosphere or a vacuum atmosphere and bringing the substrate 10 on which the organic material is deposited into the sus 20. After that a certain force is applied to the ultraviolet rays to cure the actual (14).

OELD according to the prior art as described above has a problem that the progressive line dead occurs as time passes after the production of the OELD to lower the reliability of the entire device.

In the organic EL device, the line dead phenomenon is related to a short circuit between the anode and the cathode. The reason for this is that pinholes, etc., formed in the metal electrode layer, which is the last layer of deposition, are formed, and the main reason for the pinholes is that the metal thin films are deposited on the ITO substrate or organic el thin film on which dust is adsorbed to a very thin thickness below um. In this case, the pinhole formed around the dust particles serves as a conductive path. The short circuit is caused by such a conductive path, and line dead occurs around this point, and there is a problem that a short circuit may occur due to a potential that may continue to occur over time, causing a progressive line dead.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to install an oxygen gas generator inside an OELD encapsulation cap to remove a short circuit path that causes progressive line dead after a certain period of time. In addition to improving reliability, OELD provides improved brightness characteristics and lifespan (a fact that has been uncovered by recent experimental results, but the mechanism is still unknown).

Oxygen oxidizes the pinhole periphery, breaking the short-circuit path to prevent progressive line dead. As a countermeasure, the surface cleaning and planarization methods of the substrates have been performed in the past, but they cannot be cleaned completely.

As such, oxygen can be used to remove short-circuit paths by using oxidative properties, but it is known to cause dark point generation and pixel size reduction, which degrade device characteristics. In order to minimize such negative effects, progressive line dead is generated. It is to provide a gas generator that can use oxygen only at the time.

Features of the OELD according to the present invention for achieving the above object,

A transparent substrate having an OEL layer serving as a light emitting portion in a display area on one surface thereof;

In the OELD having an encapsulation cap bonded to the light emitting portion of the transparent substrate to block the OEL layer from the outside,

An inner portion of the encapsulation cap is provided with an oxygen gas generator, and after a predetermined time, oxygen gas is supplied into the encapsulation cap to remove a short circuit path.

In addition, the encapsulation cap is formed of one material arbitrarily selected from the group consisting of sus, polymer film, stainless steel and glass,

The oxygen gas generator and the chamber is provided with an oxygen gas generator;

A heating element for heating the oxygen gas generator in the chamber;

It is characterized by consisting of a power supply and a switching unit connected to the heating element.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a cross-sectional view of the sealing cap of the OELD according to an embodiment of the present invention, an example of a scan.

First, the encapsulation cap of the OELD according to the embodiment of the present invention is a recess scan 32 made of a sus material, and a recess 32 is formed at the center thereof, and a peripheral portion has a flat adhesive surface 34 and a recess 32. The moisture absorbent 36 is installed in the center of the oxygen gas supply unit 40 in the periphery thereof.

The thirty cans 30 are sealed with a sealant on a glass substrate provided with an OEL layer.

Wherein the oxygen gas supplier 40 has a structure as shown in FIG.

That is, the oxygen gas generator 44 is provided in the chamber 42, and is connected to the heating element 45, the power supply unit 46, and the switching unit 48, which are separately provided. Here, the oxygen gas generator 44 is a material such as sodium nitrate, and is a material that discharges oxygen gas when heat is applied to a solid material, and the reaction is as follows.

2NaNO3 (S) → 2NaNO ₂ (S) + O2 (G)

After the OELD is used for a certain period of time after the actual process, the oxygen gas generator 40 installed in this manner is applied with a power source before the advanced line death proceeds to generate a certain amount of oxygen gas to cut off a short circuit pass to improve the reliability of the device. Can be.

Here, the power supply 46 and the switching unit 48 may be exposed to the outside of the scan 30 or may be used in connection with the OELD power, and the power supply 46 and the switching unit 48 may be used separately. It can also be used. In addition, the switching unit 48 may be replaced with a timer.

In addition, the encapsulation cap may be formed of a polymer film, stainless steel, or the like as a main material as well as a sus, and a glass cap may be used.

Figure 4 is a cross-sectional view of the sealing cap of the OELD according to another embodiment of the present invention, an example of a glass cap having a groove.

First, the groove 52 is provided in the center portion, and the moisture absorbent 36 and the oxygen gas supply 40 shown in FIG. 3 are installed in the center portion of the glass cap 50 having the adhesive portion 54 in the peripheral portion thereof. , The glass cap 50 is actually sealed to the glass substrate provided with the OEL layer.

Here, the power supply unit 46 and the switching unit 48 of the oxygen gas generator 40 may be exposed to the outside of the scan 30 or the glass cap 50 or may be used in connection with an OELD power source. The 46 and the switching unit 48 may be connected to a separate power source for use. In addition, the switching unit 48 may be replaced with a timer.

As described above, the OELD according to the present invention, in the OELD having an encapsulation cap that is bonded to the substrate surface having the OEL layer and protects the OEL layer, attaches an oxygen gas generator to the inside of the encapsulation cap, and By filling oxygen gas inside and oxidizing the short-circuit path at the cathode electrode exposed to oxygen, it is possible to eliminate the short-circuit path, which is the cause of the progressive line death that proceeds with the use of OELD, thereby preventing the deterioration of device reliability. In addition, there is an advantage in that the image quality of the device can be improved by improving the luminance characteristic and the lifetime.

Claims (4)

A transparent substrate having an OEL layer serving as a light emitting portion in a display area on one surface thereof; In the OELD having an encapsulation cap bonded to the light emitting portion of the transparent substrate to block the OEL layer from the outside, OELD, characterized in that provided with an oxygen gas generator in the inner portion of the encapsulation cap to remove the short circuit path by supplying oxygen gas into the encapsulation cap after a predetermined time. The method of claim 1, OELD, characterized in that the encapsulation cap is formed of one material arbitrarily selected from the group consisting of sus, polymer film, stainless steel and glass. The method of claim 1, The oxygen gas generator and the chamber is provided with an oxygen gas generator; A heating element for heating the oxygen gas generator in the chamber; OELD, characterized in that consisting of a power supply and a switching unit connected to the heating element. The method of claim 3, wherein OELD, characterized in that the oxygen gas generator is sodium nitrate.

Images