| 摘要 |
<p>PURPOSE:To simplify the structure of a detection part, by providing an adequate number of transparent electrode couples at display positions of an electric insulating transparent display plate, and short-circuiting them selectively in terms of capacity by a finger touch. CONSTITUTION:When plural display contents projected on the transparent display plate, e.g. items in a menue are specified selectively with a finger, the pluse application electrode 6 and sense electrode 7 connected to the pulse generating circuit 8 of a facing electrode couple 5 are short-circuited in terms of capacity. Then, while the input voltage of a high input impedance amplifier 10 drops gradually below a threshold value, the amplifier 10 generates an H-level output. When the H-level output falls, an one-shot multivibrator 11 is triggered to output an H-level signal. The output voltage of the amplifier 10 and the output voltage of the multivibrator 11 are ORed by an OR circuit 12, whose output is led out. Consequently, the detection structure part is simplified greatly and a simple detecting circuit is realized.</p> |
