POWER SUPPLY CIRCUIT, SIGNAL LINE DRIVE CIRCUIT, ITS DRIVE METHOD, AND LIGHT-EMITTING DEVICE

摘要

The device characteristics of a transistor tends to vary because of the nonuniformity of the thicknesses of a semiconductor film and gate insulating film formed during the production process and because of the patterning accuracy of the films. Particularly in the case of polysilicon transistors, the crystallinity may vary because of the crystal growth direction and of the defects at the grain boundaries. According to the invention, a method for driving a signal line drive circuit is characterized in that the signal current supplied from a current source circuit having current sources provided to lines is set to a predetermined value by using a reference constant current source and in that the electrical connection between the line to which the signal current is outputted and the current sources are changed over in predetermined cycles.