Patent Number: 7,042,162

Title: Light emitting device

Abstract: The light-emitting element has a problem that reliability, heat-resisting stability and durability are low because of the deterioration in an organic compound layer. The TFT for driving the light-emitting element has a problem that variation readily occurs in its electrical characteristic due to the defects existing in grain boundaries. The present invention provides a light-emitting device by using the fact that, by applying to the light-emitting element a drive voltage having a polarity reverse to that in light emission during each constant period, the light-emitting element is improved in current-voltage characteristic. Furthermore, the present invention provides a light-emitting device made not dependent upon transistor characteristic, by controlling the amount of a current flowing through the light-emitting element.

Inventors: Yamazaki; Shunpei (Setagaya, JP), Seo; Satoshi (Kawasaki, JP), Kimura; Hajime (Atsugi, JP), Yamazaki; Yu (Setagaya, JP), Fukumoto; Ryota (Atsugi, JP)

Assignee: Semiconductor Energy Laboratory Co., Ltd.

International Classification: G09G 3/10 (20060101)

Expiration Date: 5/09/02018