Stock material or miscellaneous articles – Composite – Of inorganic material
Reexamination Certificate
2000-07-14
2002-12-03
Garrett, Dawn L. (Department: 1774)
Stock material or miscellaneous articles
Composite
Of inorganic material
C313S506000, C313S509000, C257S102000
Reexamination Certificate
active
06489045
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an organic electroluminescence device exhibiting a high power efficiency.
An organic electroluminescence device, hereinafter referred to as “an organic EL device”, can be comparatively easily produced as a surface luminescence device by a vapor deposition method, a coating method, etc., thereby considered to be useful for a flat panel display. The organic EL device has been widely studied, and such that providing an excellent performance equal to an inorganic LED has been developed in recent years.
The organic EL device ordinarily comprises a pair of electrodes. Since the organic EL device acts as a surface luminescence device, at least one of the electrodes generally has a low resistance and a high light-transmittance. Well known as such an electrode is, for example, an electrode of ITO (Indium Tin Oxide) where indium oxide is doped with tin (see, Japanese Patent Laid-Open No. 11-67460). Nevertheless, it has been desired to develop an electrode having a lower resistance and more efficient light-transmitting characteristics than those of known electrodes, and an organic EL device comprising the electrode to exhibit a higher power efficiency as compared with the prior art.
OBJECT AND SUMMARY OF THE INVENTION
An object of the present invention is to provide an organic EL device exhibiting a high power efficiency.
As a result of intense research in view of the above object, the inventors have found that an organic EL device comprising a light-transmittable electrode having specific light-transmitting characteristics is excellent in the power efficiency. The present invention has been accomplished by the finding.
Thus, an organic EL device of the present invention comprises a pair of electrodes and at least one organic compound layer disposed therebetween, wherein at least one of the electrodes is a light-transmittable electrode exhibiting a light-transmittance peak centered in a range of an emission peak wavelength of the device ±100 nm, and the light-transmittance peak has a half band width of 1 to 350 nm.
The organic EL device of the present invention provides a further improved power efficiency by satisfying the following conditions (1) to (4).
(1) It is preferable that the light-transmittable electrode has a surface resistance of 15 &OHgr;/square or less.
(2) It is preferable that the light-transmittable electrode is a multi-layered thin film composed of preferably 2 or more materials, more preferably 3 or more materials.
(3) It is preferable that the light-transmittable electrode is mainly composed of ITO, indium oxide, tin oxide, and/or an indium oxide-zinc oxide alloy.
(4) It is preferable that the organic EL device emits light by applying a pulse voltage having a pulse width of 10
−9
to 10
−3
second.
REFERENCES:
patent: 5723873 (1998-03-01), Yang
patent: 5986391 (1999-11-01), Feldman
patent: 6030700 (2000-02-01), Forrest et al.
patent: 6207301 (2001-03-01), Ohnishi et al.
patent: 6280861 (2001-08-01), Hosokawa et al.
patent: 6309763 (2001-10-01), Woo et al.
patent: 07022649 (1995-01-01), None
patent: 11067460 (1999-03-01), None
Araki Yasushi
Okaniwa Masayuki
Fuji Photo Film Co., LTD
Garrett Dawn L.
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