| 摘要 |
<p>PURPOSE:To specify an optional position on a display and to input it to a device by providing a coordinate detection circuit comparing the output of a write pen and the scanning signal of a liquid crystal panel. CONSTITUTION:In the case of a projection type liquid crystal display device having plural liquid crystal panels 14, 15 and synthesizing them on a screen 20, a scanning direction is different from each other at every panel. That is, a certain panel 14 is scanned in a vertical direction and the other panel 15 is scanned in a horizontal direction. Further, by using two write pens with different frequencies from each other, beams in a vertical and a horizontal directions are monitored individually and the vertical/horizontal coordinates of an optional point is detected by comparing with a frame signal by them. By such a simple constitution, a position is detected by the write pen and a device is miniaturized compared with a touch panel system and the value added of the device is enhanced.</p> |
