Patent ID: 7123237

Claim:
A display device having a level converting circuit including thin film transistors formed on a substrate, wherein the level converting circuit converts non-differential input signals having an amplitude of 1.2V or less into signals having a larger amplitude, wherein the input signals are control signals, wherein the input signals are control signals, and the level converting circuit includes: a first-conductive-type first transistor which is connected between a first power source line to which a first voltage is supplied and an output terminal and has a gate electrode to which the input signals are applied through a first capacitive element; a second-conductive-type second transistor which is connected between the output terminal and a second power source line to which a second voltage is supplied and has a gate electrode to which the input signals are applied through a second capacitive element; a first bias circuit which applies a first bias voltage to the gate electrode of the first transistor; and a second bias circuit which applies a second bias voltage to the gate electrode of the second transistor, wherein the first bias voltage is a voltage which turns off the first transistor when a voltage applied to the gate electrode of the first transistor assumes a maximum value, and the second bias voltage is a voltage which turns off the second transistor when a voltage applied to the gate electrode of the second transistor assumes a minimum value.