06641933 is referenced by 148 patents and cites 4 patents.

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 3×10

10

&OHgr;cm 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.

Title
Light-emitting EL display device
Application Number
9/667493
Publication Number
6641933 (B1)
Application Date
September 21, 2000
Publication Date
November 4, 2003
Inventor
Mayumi Mizukami
Kanagawa
US
Toshimitsu Konuma
Kanagawa
US
Shunpei Yamazaki
Tokyo
US
Agent
Robinson Intellectual Property Law Office P C
US
Agent
Eric J Robinson
US
Assignee
Semiconductor Energy Laboratory
US
IPC
H05B 33/14
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