In a structure in which six active matrix regions 103 to 108 are integrated on one glass substrate, horizontal scanning control circuits 101 and 102 are commonly disposed for the respective active matrix regions 103 to 105 and 106 to 108. Then the horizontal scanning control circuits 101 and 102 are operated at different timings, and images formed by the active matrix regions 103 to 105 and 106 to 108 are synthesized and projected. With this operation, the horizontal scanning frequency required for one horizontal scanning control circuit can be made half of the horizontal scanning frequency of the display screen.