Coating processes – Electrical product produced – Fluorescent or phosphorescent base coating
Reexamination Certificate
1998-07-17
2001-12-25
Beck, Shrive P. (Department: 1762)
Coating processes
Electrical product produced
Fluorescent or phosphorescent base coating
C427S535000, C427S539000
Reexamination Certificate
active
06333065
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an organic EL device using an organic compound, and more specifically, it relates to an improvement of an interface between the hole-injecting electrode and the organic layer of an organic EL device.
PRIOR ART
In recent years, organic EL devices have been actively studied. Organic EL devices have a basic configuration structured by vaporizing a hole-transporting material such as triphenyldiamine (TPD) to form a thin film on a hole-injecting electrode, further laminating a light-emitting layer of a fluorescent material such as an aluminum quinol complex (Alq3) and further forming a metal electrode (electron-injecting electrode) having a low work function such as Mg. These organic EL devices are attracting attention due to their capability of a very high luminance of several 100 to several 10,000 cd/m
2
at a voltage of about 10 V.
It is considered that a material capable of injecting many holes into a light-emitting layer or a hole-injecting/transporting layer is effective for use in an hole-injecting electrode of the above organic EL devices. In most configurations, generally, emitted light is arranged to come out through a substrate side, and the material for hole-injecting electrode is required to be a transparent electrically conductive material.
For the above transparent electrode, there are known ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), ZnO, SnO
2
, In
2
O
3
and the like. Of these, an ITO electrode is a transparent electrode having a visible light transmittance of at least 90% and a sheet resistance of 10&OHgr;/□ or less, and it is widely used as a transparent electrode for a liquid crystal display (LCD), dimmer glass and a solar cell and is expected to be promising as a hole-injecting electrode of an organic EL device.
Meanwhile, an organic EL device tends to deteriorate with the passage of time, and it is an essential object how to prevent the deterioration. There are many factors which are considered to deteriorate the device. The deterioration in the film interface between the electrode and the organic layer has a great influence on the lifetime and the light-emission characteristic of the device, and it is an essential object to modify the device in property with regard to the above interface.
An organic EL device is constituted by forming a film of a hole-injecting electrode from the above ITO, etc. on a substrate, then forming organic layers such as a hole-injection and transporting layer and a light-emitting layer and further forming an electron-injecting electrode. When the hole-injecting electrode surface is contaminated during the formation of the organic layer after the layer of the hole-injecting electrode is formed, the efficiency of hole injection into the formed organic layer decreases. As a result, the light emission efficiency is caused to decrease, and a light-non-emitting area called a dark spot is caused to appear or a dark spot is caused to expand. Particularly, the hole-injecting electrode formed of ITO, etc., is produced in a step separate from the production step of the organic layers, or hole injecting electrodes manufactured by other manufacturer are purchased, in many cases. The surface thereof is often contaminated, and a cleaning step is therefore essential.
Attempts have been made in various ways to clean the surface of a substrate after the formation of the hole-injecting electrode. In one method, for example, a UV lamp is provided in a layer-forming chamber, it is turned on, and O
2
gas is introduced to carry out UVO
3
cleaning. However, the above method has problems that the layer-forming chamber is required to share a space with the UV lamp and that the freedom of machine designing is decreased due to the location of the UV lamp. Further, O
3
is generated in the layer-forming chamber, and the above method is therefore not satisfactory with respect of process capacity and process speed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus and a process for an organic EL device, which permits a high freedom of apparatus designing, permits effective processing and gives an organic EL device having a high light emission efficiency and excellent device characteristics.
According to the present invention, the above object is achieved by any one of the following constitutions (1) to (3).
(1) An apparatus for producing an organic EL device, comprising
means of cleaning a surface of a substrate on which at least a hole-injecting electrode is formed, and
means of forming an organic layer on the cleaned surface of the substrate,
the cleaning means being for performing the cleaning with ozone gas generated with an ozonizer under a reduced pressure of 1.33×10
4
Pa or less.
(2) In the above apparatus (1), the ozonizer is located by separating it from a layer-forming chamber.
(3) A process for the production of an organic EL device, comprising
forming a hole-injecting electrode on a substrate,
cleaning the substrate on which the hole-injecting electrode is formed, with ozone generated with an ozonier, and
forming an organic layer within 60 minutes from the cleaning.
REFERENCES:
patent: 4872947 (1989-10-01), Wang et al.
patent: 4892753 (1990-01-01), Wang et al.
patent: 4895291 (1990-01-01), Ozimek et al.
patent: 5505985 (1996-04-01), Nakamura et al.
patent: 5674635 (1997-10-01), Hsieh et al.
patent: 5792326 (1998-08-01), Harada et al.
patent: 5817431 (1998-10-01), Shi et al.
patent: 5963826 (1999-10-01), Takanabe et al.
patent: 6001413 (1999-12-01), Matsuura et al.
patent: 6020078 (2000-02-01), Chen et al.
patent: 6034755 (2000-03-01), Watanabe
patent: 7-142168 (1995-06-01), None
Arai Michio
Nakaya Kenji
Beck Shrive P.
Cleveland Michael
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
TDK Corporation
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