The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 14, 2015
Filed:
Apr. 04, 2008
Yoriko Nakayama, Tokyo, JP;
Tomoyuki Nakayama, Tokyo, JP;
Kunimasa Hiyama, Tokyo, JP;
Shigeru Kojima, Tokyo, JP;
Yoriko Nakayama, Tokyo, JP;
Tomoyuki Nakayama, Tokyo, JP;
Kunimasa Hiyama, Tokyo, JP;
Shigeru Kojima, Tokyo, JP;
Konica Minolta Holdings, Inc., Tokyo, JP;
Abstract
Disclosed is a white light-emitting organic electroluminescent device, which is excellent in stability of emission chromaticity over a long operation period, while having high electrical efficiency, long life, excellent storage stability and excellent color rendering properties. Also disclosed is an illuminating device using such an organic electroluminescent device. Specifically disclosed is an organic electroluminescent device having a light-emitting layer between an anode and a cathode, which is characterized by comprising a light-emitting layer A having a maximum emission wavelength of not more than 480 nm and containing a phosphorescent dopant having a maximum emission wavelength of not more than 480 nm, and a light-emitting layer B arranged between the light-emitting layer A and the anode, which has a maximum emission wavelength of not less than 510 nm and contains a phosphorescent dopant. This organic electroluminescent device is also characterized in that the concentration of the phosphorescent dopant contained in the light-emitting layer A varies in the thickness direction of the light-emitting layer A. Also specifically disclosed is an illuminating device using such a white light-emitting organic electroluminescent device.