| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection display device capable of preventing printing by optimizing the polarity of a driving circuit of a reflection type spatial light modulation element and suppressing the impression of a DC component to a liquid crystal layer independently of the contents of a video signal. SOLUTION: A vertically synchronizing signal detected from an input video signal by a synchronization detection circuit 21 and a scene change detection signal outputted from a scene change detection circuit 22 are supplied to a driving polarity selection circuit 23. In order to select the polarity of liquid crystal impression voltage for driving a spatial light modulation element 25r, the driving polarity selection circuit 23 generates a control signal A for a change-over switch (SW) 25c for switching a video signal processing circuit 25a and a polarity inversion circuit 25b. COPYRIGHT: (C)2005,JPO&NCIPI
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