Video display device

摘要

In a projection type video display device according to the present invention comprising light writing type spacial light modulator, disturbances brought about by resetting pulse and appeared in projected picture as black belt or beat are prevented by causing the resetting pulse, which is to withdraw electric charges produced by incomming writing light and accumulated in spacial light modulator, to occur within a vertical blanking period synchronized with vertical synchronous signal. Further, by changing the pulse width and the voltage of resetting pulse in accordance with vertical synchronous frequency, pictures of a certain fixed brightness are made available against various vertical synchronous frequencies; and even with a high vertical synchronous frequency, projected pictures are never annoyed by such disturbance that is caused by a resetting pulse dislocated out of the vertical blanking period. Further, by controlling the adjustments of writing voltage to be applied to spacial light modulator during writing period and resetting voltage to be applied to spacial light modulator during resetting period, the spread in characteristics of spacial light modulator is compensated to provide a certain fixed contrast and gamma characteristic. Furthermore, in a video display device for full-color display, as writing voltage and resetting voltage can be established independently corresponding to respective three RGB primary colors video outputs of any desired color temperature are obtainable by adjusting the balance of light emission among the three RGB colors. <IMAGE>