Method for driving semiconductor device

Abstract

To provide a method for driving a semiconductor device, by which influence of variation in threshold voltage and mobility of transistors can be reduced. The semiconductor device includes an n-channel transistor, a switch for controlling electrical connection between a gate and a first terminal of the transistor, a capacitor electrically connected between the gate and a second terminal of the transistor, and a display element. The method has a first period for holding the sum of a voltage corresponding to the threshold voltage of the transistor and an image signal voltage in the capacitor; a second period for turning on the switch so that electric charge held in the capacitor in accordance with the sum of the image signal voltage and the threshold voltage is discharged through the transistor; and a third period for supplying a current to the display element through the transistor after the second period.

1 . (canceled) 
     
     
         2 . A light-emitting device comprising:
 a pixel, the pixel comprising:
 a first transistor, a second transistor, a third transistor, a fourth transistor, and a fifth transistor; 
 a light-emitting element; and 
 a capacitor, 
   wherein a gate of the first transistor is electrically connected to a first wiring,   wherein one of a source and a drain of the first transistor is electrically connected to a first electrode of the light-emitting element,   wherein the other of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the second transistor,   wherein a gate of the second transistor is electrically connected to a first electrode of the capacitor, one of a source and a drain of the third transistor, and one of a source and a drain of the fourth transistor,   wherein a gate of the fourth transistor is electrically connected to a second wiring,   wherein the other of the source and the drain of the fourth transistor is electrically connected to a third wiring,   wherein the other of the source and the drain of the second transistor is electrically connected to one of a source and a drain of the fifth transistor,   wherein the other of the source and the drain of the fifth transistor is electrically connected to a fourth wiring, and   wherein a gate of the fifth transistor is electrically connected to a fifth wiring.   
     
     
         3 . A light-emitting device comprising:
 a pixel, the pixel comprising:
 a first transistor, a second transistor, a third transistor, a fourth transistor, and a fifth transistor; 
 a light-emitting element; and 
 a capacitor, 
   wherein a gate of the first transistor is electrically connected to a first wiring,   wherein one of a source and a drain of the first transistor is electrically connected to a first electrode of the light-emitting element,   wherein the other of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the second transistor,   wherein a gate of the second transistor is electrically connected to a first electrode of the capacitor, one of a source and a drain of the third transistor, and one of a source and a drain of the fourth transistor,   wherein a gate of the fourth transistor is electrically connected to a second wiring,   wherein the other of the source and the drain of the fourth transistor is electrically connected to a third wiring,   wherein the other of the source and the drain of the second transistor is electrically connected to one of a source and a drain of the fifth transistor,   wherein the other of the source and the drain of the fifth transistor is electrically connected to a fourth wiring,   wherein a gate of the fifth transistor is electrically connected to a fifth wiring,   wherein the light-emitting device is configured to correct a threshold voltage and mobility of the second transistor, and   wherein the second transistor is configured to control a supply of a current to the light-emitting element according to a video signal.   
     
     
         4 . A light-emitting device comprising:
 a pixel, the pixel comprising:
 a first transistor, a second transistor, a third transistor, a fourth transistor, and a fifth transistor; 
 a light-emitting element; and 
 a capacitor, 
   wherein a gate of the first transistor is electrically connected to a first wiring,   wherein one of a source and a drain of the first transistor is electrically connected to a first electrode of the light-emitting element,   wherein the other of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the second transistor,   wherein a gate of the second transistor is electrically connected to a first electrode of the capacitor, one of a source and a drain of the third transistor, and one of a source and a drain of the fourth transistor,   wherein a gate of the fourth transistor is electrically connected to a second wiring,   wherein the other of the source and the drain of the fourth transistor is electrically connected to a third wiring,   wherein the other of the source and the drain of the second transistor is electrically connected to one of a source and a drain of the fifth transistor,   wherein the other of the source and the drain of the fifth transistor is electrically connected to a fourth wiring,   wherein a gate of the fifth transistor is electrically connected to a fifth wiring,   wherein the light-emitting device is configured to correct a threshold voltage and mobility of the second transistor,   wherein the second transistor is configured to control a supply of a current to the light-emitting element according to a video signal, and   wherein one of the first to fifth transistors comprises an oxide semiconductor in a channel portion.