Thin film semiconductor device and liquid crystal display apparatus using thereof

The invention relates to a thin film semiconductor device and a liquid crystal display apparatus. In the thin film semiconductor device, because light irradiated to the thin film semiconductor device is cut off by a conductor layer, the light can be prevented from reaching the semiconductor layer. Therefore generation of carriers due to optical excitation does not occur and off current can be reduced. In the thin film semiconductor device, because there is no area where electric field intensity of an opposed direction of the source electrode and the drain electrode is weaker than that in the channel region in the semi­conductor layer, even after an operation for a prolonged duration under the irradiation of light, carriers generated by optical excitation are not accumulated in the semiconductor layer, and probability of the trapping for the carriers into a gate insulating film is quite low, and therefore variation in the characteristics of the thin film semiconductor device is negligibly small. The liquid crystal display apparatus using the thin film semiconductor can restrict such deterioration of display quality as the degradation of contrast and uniformity.