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:
May. 17, 2011
Filed:
Mar. 08, 2004
Hiroko Yamazaki, Kanagawa, JP;
Hiroko Yamazaki, Kanagawa, JP;
Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;
Abstract
A high efficient white emission light emitting element having peak intensity in each wavelength region of red, green, and blue is provided. Specifically, a white emission light emitting element having an emission spectrum that is independent of current density is provided. A first light emitting layerexhibiting blue emission and a second light emitting layercontaining a phosphorescent material that generates simultaneously phosphorescent emission and excimer emission are combined. In order to derive excimer emission from the phosphorescent material, it is effective to disperse a phosphorescent materialhaving a high planarity structure such as platinum complex at a high concentration of at least 10 wt % to a host material. Further, the first light emitting layeris provided to be in contact with the second light emitting layerat the side of an anode. Ionization potential of the second light emitting layeris preferably larger by 0.4 eV than that of the first light emitting layer