Patent ID: 7893913

Claim:
A display device comprising: a substrate having an insulating surface; a pixel portion comprising: a pixel including: a thin film transistor over the substrate; and a display element electrically connected to the thin film transistor; and a signal line electrically connected to the thin film transistor; and a driving circuit comprising: a first shift register; a first level shifter electrically connected to the first shift register; a first constant current source electrically connected to the first level shifter; a second constant current source electrically connected to the first constant current source; a second level shifter electrically connected to the second constant current source; a second shift register for controlling on and off of the first constant current source and the second constant current source; and a latch circuit to which a first pulse is inputted from the first shift register and a second pulse is inputted from the second level shifter, wherein a first clock signal is inputted into the first shift register, wherein a second clock signal is inputted into the second shift register, and wherein a frequency of the second clock signal is lower than a frequency of the first clock signal.