Electronic device, display device, and semiconductor device and method for driving the same

Abstract

A pixel having a transistor which controls a current value supplied to a load, a first storage capacitor, a second storage capacitor, and first to fourth switches is included. After the threshold voltage of the transistor is held in the second storage capacitor, a potential in accordance with a video signal is input to the pixel. Voltage obtained by adding a potential in which the potential in accordance with the video signal and the first storage capacitor are capacitively divided to the threshold voltage is held in the second storage capacitor in this manner, so that variation of a current value caused by variations in the threshold voltage of the transistor is suppressed. Thus, desired current can be supplied to the load such as a light-emitting element. In addition, a display device with little deviation from luminance specified by the video signal can be provided.

1 . (canceled) 
     
     
         2 . A semiconductor device comprising:
 a transistor comprising:
 a gate electrode over a substrate; and 
 a semiconductor layer over the gate electrode with a first insulating film therebetween; 
   a first capacitor;   a second capacitor;   a first switch;   a second switch; and   a light-emitting element,   wherein one of a source and a drain of the transistor is electrically connected to the light-emitting element,   wherein a gate of the transistor is electrically connected to the first switch,   wherein the one of the source and the drain of the transistor is electrically connected to the second switch,   wherein the gate of the transistor is electrically connected to a first electrode of the first capacitor,   wherein the one of the source and the drain of the transistor is electrically connected to a second electrode of the first capacitor,   wherein the gate of the transistor is electrically connected to a first electrode of the second capacitor,   wherein a second insulating film is over and in contact with the semiconductor layer, and   wherein a wiring is over the second insulating film and in contact with the semiconductor layer through an opening formed in the second insulating film.   
     
     
         3 . The semiconductor device according to  claim 2 , wherein a second electrode of the second capacitor is electrically connected to a signal line. 
     
     
         4 . The semiconductor device according to  claim 2 , wherein the gate of the transistor is electrically connected to the other of the source and the drain of the transistor via the first switch. 
     
     
         5 . The semiconductor device according to  claim 2 , wherein the light-emitting element is electrically connected to a first potential supply line via the second switch. 
     
     
         6 . The semiconductor device according to  claim 2 , wherein the semiconductor layer comprises an oxide semiconductor. 
     
     
         7 . The semiconductor device according to  claim 6 , wherein the oxide semiconductor is InGaZnO. 
     
     
         8 . The semiconductor device according to  claim 2 , further comprising:
 a third switch;   a fourth switch; and   a fifth switch,   wherein the other of the source and the drain of the transistor is electrically connected to a power supply line via the third switch,   wherein a second electrode of the second capacitor is electrically connected to a signal line via the fourth switch, and   wherein the second electrode of the second capacitor is electrically connected to a second potential supply line via the fifth switch.   
     
     
         9 . A display device comprising the semiconductor device according to  claim 2 . 
     
     
         10 . An electronic device comprising the display device according to  claim 9  in a display portion. 
     
     
         11 . A semiconductor device comprising:
 a first transistor comprising:
 a gate electrode over a substrate; and 
 a semiconductor layer over the gate electrode with a first insulating film therebetween; 
   a first capacitor;   a second capacitor;   a second transistor;   a third transistor; and   a light-emitting element,   wherein one of a source and a drain of the first transistor is electrically connected to the light-emitting element,   wherein a gate of the first transistor is electrically connected to one of a source and a drain of the second transistor,   wherein the one of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the third transistor,   wherein the gate of the first transistor is electrically connected to a first electrode of the first capacitor,   wherein the one of the source and the drain of the first transistor is electrically connected to a second electrode of the first capacitor,   wherein the gate of the first transistor is electrically connected to a first electrode of the second capacitor,   wherein a second insulating film is over and in contact with the semiconductor layer, and   wherein a wiring is over the second insulating film and in contact with the semiconductor layer through an opening formed in the second insulating film.   
     
     
         12 . The semiconductor device according to  claim 11 , wherein a second electrode of the second capacitor is electrically connected to a signal line. 
     
     
         13 . The semiconductor device according to  claim 11 , wherein the other of the source and the drain of the second transistor is electrically connected to the other of the source and the drain of the first transistor. 
     
     
         14 . The semiconductor device according to  claim 11 , wherein the other of the source and the drain of the third transistor is electrically connected to a first potential supply line. 
     
     
         15 . The semiconductor device according to  claim 11 , wherein the semiconductor layer comprises an oxide semiconductor. 
     
     
         16 . The semiconductor device according to  claim 15 , wherein the oxide semiconductor is InGaZnO. 
     
     
         17 . The semiconductor device according to  claim 11 , further comprising:
 a fourth transistor;   a fifth transistor; and   a sixth transistor,   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 fourth transistor,   wherein the other of the source and the drain of the fourth transistor is electrically connected to a power supply line,   wherein a second electrode of the second capacitor 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 signal line,   wherein the second electrode of the second capacitor is electrically connected to one of a source and a drain of the sixth transistor, and   wherein the other of the source and the drain of the sixth transistor is electrically connected to a second potential supply line.   
     
     
         18 . A display device comprising the semiconductor device according to  claim 11 . 
     
     
         19 . An electronic device comprising the display device according to  claim 18  in a display portion.