Light-emitting device and driving method thereof

Patent metadata

Field	Value
Publication number	US-8941314-B2
Application number	US-201213666055-A
Country	US
Kind code	B2
Filing date	Nov 1, 2012
Priority date	Oct 26, 2001
Publication date	Jan 27, 2015
Grant date	Jan 27, 2015

Abstract

In a light emitting device, luminance irregularities caused by fluctuation in threshold of TFTs for supplying a current to EL elements among pixels hinder the light emitting device from improving the image quality. A voltage equal to the threshold of a TFT 110 is held in capacitor means 111 in advance. When a video signal is inputted from a source signal line, the voltage held in the capacitor means is added to the signal, which is then applied to a gate electrode of the TFT 110 . Even when threshold is fluctuated among pixels, each threshold is held in the capacitor means 111 of each pixel, and therefore, influence of the threshold fluctuation can be removed. Since the threshold is stored in the capacitor means 111 alone and the voltage between two electrodes is not changed while a video signal is written, fluctuation in capacitance value has no influence.

First claim

What is claimed is:

1. A semiconductor device comprising:
a first transistor comprising a first gate, a first source, and a first drain;
a second transistor comprising a second gate, a second source, and a second drain;
a third transistor comprising a third gate, a third source, and a third drain;
a fourth transistor comprising a fourth gate, a fourth source, and a fourth drain;
a fifth transistor comprising a fifth gate, a fifth source, and a fifth drain;
a sixth transi…

Assignees

• Semiconductor Energy Lab

Inventors

• Kimura Hajime

Classifications

• G09G2300/0842

  Physics · mapped topic

• G09G2300/0819

  Physics · mapped topic

• G09G3/2022

  Physics · mapped topic

• G09G3/3233 Primary

  Physics · mapped topic

• G09G2300/0861

  Physics · mapped topic