| 摘要 |
<p>PURPOSE:To prevent the erroneous detection of contact position coordinates due to the influence of a flaw, etc., on a resistance film by connecting a first power source terminal through a resistor to one terminal, connecting a second power source terminal to the other terminal and providing a voltage measuring circuit to measure the terminal voltage of the resistor. CONSTITUTION:For example, the flaw, etc., is attached in a position shown by X on a resistance film 3. The resistance value of the resistance film 3 is made high by DELTARx by the flaw, etc., and goes to be (Rx+R1-x+DELTARx). On the other hand, since the resistance value of a resistor 1 is R0 and fixed, the terminal voltage of the resistor 1 goes to be R0.Vcc/(R0+Rx+R1-x+DELTARX) and it is a reference voltage. Thus, an alarm signal is generated by a voltage measuring circuit 4 and supplied to an MPU and it is informed of the MPU that the resistance value of the resistance film 3 is changed. Thus, before next impedance measurement is started, the MPU can know that the resistance value of the resistance film 3 is changed.</p> |
