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. 15, 2014
Filed:
Nov. 01, 2011
Shunpei Yamazaki, Setagaya, JP;
Toshimitsu Konuma, Atsugi, JP;
Mayumi Mizukami, Atsugi, JP;
Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;
Abstract
By repeating a purification process of a light-emitting organic compound several times, a thin film made of the light-emitting organic compound to be used in an EL display device contains ionic impurities at the concentration of 0.1 ppm or lower and has a volume resistivity in the range of 3×10Ωcm or larger. By using such a thin film as a light-emitting layer in the EL device, a current caused by reasons other than the carrier recombination can be prevented from flowing through the thin film, and deterioration caused by unnecessary heat generation can be suppressed. Accordingly, it is possible to obtain an EL display device with high reliability.