TOUCH PANEL COORDINATE POSITION DETECTION DEVICE

摘要

A touch panel coordinate position detection device includes: charge circuits (12, 14) having a function for charging a coupling capacitance of a capacitive touch panel (2) having a position detection resistance film (2B) cyclically fluctuating between plus and minus and a reset function for resetting the charged coupling capacitance to the state before charge; current-voltage conversion circuits (15, 16) for converting to a voltage, an accumulated value of the charge current of the coupling capacitance after the charge circuits (12, 14) has supplied current to the coupling capacitance several times; and an operation device (17) for detecting a contact coordinate position according to the output of the current-voltage conversion circuits (15, 16). The number of charging times when the position detection resistance film (2B) is at plus potential is substantially identical to the number of charging times when the position detection resistance film (2B) is at minus potential. With this configuration, it is possible to accurately detect the contact coordinate position even when the potential of the position detection resistance film cyclically fluctuates.