| 摘要 |
A transistor causes fluctuation in the threshold and mobility due to the factor such as fluctuation of the gate length, the gate width, and the gate insulating film thickness generated by the difference of the manufacturing steps and the substrate to be used. As a result, there is caused fluctuation in the current value supplied to the pixel due to the influence of the characteristic fluctuation of the transistor, resulting in generating streaks in the display image. A light emitting device is provided which reduces influence of characteristics of transistors in a current source circuit constituting a signal line driving circuit until the transistor characteristics do not affect the device and which can display a clear image with no irregularities. A signal line driving circuit of the present invention can prevent streaks in a displayed image and uneven luminance. Also, the present invention makes it possible to form elements of a pixel portion and driving circuit portion from polysilicon on the same substrate integrally. In this way, a display device with reduced size and current consumption is provided as well as electronic equipment using the display device.
|
