APPARATUS AND METHOD FOR DETECTING TOUCH, CAPABLE OF REDUCING PARASITIC CAPACITANCE

摘要

A touch detection apparatus includes at least one sensor pad outputting a signal according to a touch state in response to an alternating voltage in a floating state after charging with an electric charge, an additional electrostatic capacitive unit electrically connected to an output terminal of the sensor pad and having a capacitance corresponding to a parasitic capacitance of the sensor pad, an electrical charging/discharging unit charging or discharging the additional electrostatic capacitive unit to make the additional electrostatic capacitive unit have an electric charge variation the same as that in the parasitic capacitance caused by the alternation of the alternating voltage but an opposite polarity, and a level shift detection unit detecting a touch signal based on a difference between voltage variations in the sensor pad caused by the alternating voltage during non-touch and caused by the alternating voltage during a touch.

主权项

1. A capacitive type touch detection apparatus, comprising:
at least one sensor pad that outputs a signal according to a touch state in response to an alternating voltage in a floating state after charging with an electric charge, said at least one sensor pad having an output terminal; an additional electrostatic capacitive unit that is electrically connected to the output terminal of the at least one sensor pad and has a capacitance corresponding to a parasitic capacitance of the at least one sensor pad; an electrical charging/discharging unit that charges or discharges the additional electrostatic capacitive unit in such a manner that the additional electrostatic capacitive unit has an electric charge variation the same as that in the parasitic capacitance caused by the alternation of the alternating voltage but an opposite polarity, an electrical charging/discharging unit having an output terminal; and a level shift detection unit that detects a touch signal based on a difference between a voltage variation in the sensor pad caused by the alternating voltage during non-touch and a voltage variation in the sensor pad caused by the alternating voltage during a touch.