Semiconductor Device and Method of Driving the Semiconductor Device

Abstract

Display irregularities in light emitting devices, which develop due to dispersions per pixel in the threshold value of TFTs for supplying electric current to light emitting elements, are obstacles to increasing the image quality of the light emitting devices. An electric potential in which the threshold voltage of a TFT (105) is either added to or subtracted from the electric potential of a reset signal line (110) is stored in capacitor means (108). A voltage, in which the corresponding threshold voltage is added to an image signal, is applied to a gate electrode of a TFT (106). TFTs within a pixel are disposed adjacently, and dispersion in the characteristics of the TFTs does not easily develop. The threshold value of to the TFT (105) is thus cancelled, even if the threshold values of the TFTs (106) differ per pixel, and a predetermined drain current can be supplied to an EL element (109).

1 . (canceled) 
     
     
         2 . A semiconductor device comprising:
 a light-emitting element;   a first transistor;   a second transistor;   a first capacitor; and   a second capacitor,   wherein one of a source and a drain of the first transistor is electrically connected to the light-emitting element,   wherein the other of the source and the drain of the first transistor is electrically connected to an electric current supply line,   wherein a first electrode of the first capacitor is electrically connected to a gate of the first transistor,   wherein a second electrode of the first capacitor is electrically connected to one of a source and a drain of the second transistor,   wherein the other of the source and the drain of the second transistor is electrically connected to a source signal line,   wherein a first electrode of the second capacitor is electrically connected to the gate of the first transistor, and   wherein a second electrode of the second capacitor is electrically connected to the electric current supply line.   
     
     
         3 . The semiconductor device according to  claim 2 , further comprising a third transistor,
 wherein one of a source and a drain of the third transistor is electrically connected to the light-emitting element, and   wherein the other of the source and the drain of the third transistor is electrically connected to an electric power source line.   
     
     
         4 . The semiconductor device according to  claim 2 , further comprising a fourth transistor,
 wherein one of a source and a drain of the fourth transistor is electrically connected to the gate of the first transistor.   
     
     
         5 . The semiconductor device according to  claim 4 ,
 wherein the other of the source and the drain of the fourth transistor is electrically 1  connected to the source signal line.   
     
     
         6 . The semiconductor device according to  claim 2 , further comprising a fifth transistor,
 wherein one of a source and a drain of the fifth transistor is electrically connected to the gate of the first transistor, and   wherein a gate of the fifth transistor is electrically connected to the gate of the first transistor.