| 摘要 |
<p>PURPOSE:To easily detect multipoint contact due to malfunction such as a careless touch by connecting either an upper resistance film or a lower one to the positive side of a power source, connecting the other to the negative side of the power source through a precision resistance, and measuring the voltage applied to the precision resistance by the use of an A/D converter. CONSTITUTION:The 1st upper electrode 3 is connected to the positive side of the power source 7 and the 2nd lower electrode 6 is connected to the negative side of the power source 7 through the 1st precision resistance 19; and the A/D converter 12 measures the voltage applied to the 1st precision resistance 19. If the upper resistance film 1 and lower resistance film 2 come into multipoint contact with each other, part of the current flowing to the upper resistance film 1 is shunt to the lower resistance film 2, so the resistance at the part of the upper resistance film 1 decreases and the voltage applied to the upper resistance film 1 drops. The voltage of the power source 7, on the other hand, is constant, so the voltage applied to a 2nd precision resistance 20 increases at the time of the multipoint contact, which is therefore detected.</p> |
