Patent ID: 7545353

Claim:
A semiconductor device comprising: at least one pixel comprising: a gate wiring; an insulating film; a film; a first transistor; a second transistor; a third transistor; a fourth transistor; a power line; a signal line; and a scanning line; wherein the film is formed of the same material as a semiconductor film of the first transistor, wherein the gate wiring is formed over the film with the insulating film interposed therebetween, wherein gate electrodes of said third and fourth transistors are electrically connected to said scanning line, wherein one of source and drain regions of said third transistor is electrically connected to said signal line, wherein one of source and drain regions of said fourth transistor is electrically connected to a drain region of said first transistor, wherein a source region of said first transistor is electrically connected to said power line, and wherein one of source and drain regions of said second transistor is electrically connected to said drain region of said first transistor.