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:
Aug. 28, 2007
Filed:
Jun. 08, 2005
Mitsuaki Osame, Kanagawa, JP;
Aya Anzai, Kanagawa, JP;
Jun Koyama, Kanagawa, JP;
Makoto Udagawa, Kanagawa, JP;
Masahiko Hayakawa, Kanagawa, JP;
Shunpei Yamazaki, Tokyo, JP;
Mitsuaki Osame, Kanagawa, JP;
Aya Anzai, Kanagawa, JP;
Jun Koyama, Kanagawa, JP;
Makoto Udagawa, Kanagawa, JP;
Masahiko Hayakawa, Kanagawa, JP;
Shunpei Yamazaki, Tokyo, JP;
Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;
Abstract
A light-emitting device which realizes a high aperture ratio and in which the quality of image is little affected by the variation in the characteristics of TFTs. A large holding capacitor Cs is not provided in the pixel portion but, instead, the channel length and the channel width of the driving TFTs are increased, and the channel capacitance is utilized as Cs. The channel length is selected to be very larger than the channel width to improve current characteristics in the saturated region, and a high Vis applied to the driving TFTs to obtain a desired drain current. Therefore, the drain currents of the driving TFTs are little affected by the variation in the threshold voltage. In laying out the pixels, further, wiring is arranged under the partitioning wall and the driving TFTs are arranged under the wiring in order to avoid a decrease in the aperture ratio despite of an increase in the size of the driving TFT. In the case of the 3-transistor pixels, the switching TFT and the erasing TFT are linearly arranged to further increase the aperture ratio.