| 摘要 |
<p>PURPOSE:To improve the controllability as well as facilitate the easy selection of the information on the screen by giving the input with the input screen using two sheets of transparent resistance plates put onto the display unit. CONSTITUTION:The transparent resistance layer of indium oxide is formed on the transparent substrate to be used as the resistance plate, and then the electrodes are provided in parallel to the horizontal end at one part and to the vertical end at the other part respectively. Operational amplifier 40 forms the constant current circuit by the negative feedback of feedback resistance R. Operational amplifiers 41 and 42 amplify the voltage applied to micro-resistances r1 and r3, and then delivers the voltage proportional to the voltage flowing to r1 and r3 to output terminals 44 and 45. As a result, the voltage proportional to the positional coordinates of contact point P emerges at terminals 44 and 45 each. At the same time, the presence or absence of the contact point is detected via comparator 43, and no current flows when no contact is secured since the area between P and P' is opened. And no voltage is applied to resistance R, and the + terminal features the earth potential. While the current flows to R when the contact is secured, along with the voltage applied to the + terminal. Accordingly, the presence or absence of the contact can be detected by setting threshold voltage VT to a proper level.</p> |
