ELECTROSTATIC CAPACITY TYPE TOUCH SENSOR

摘要

The invention provides an electrostatic capacity type touch sensor that is not influenced by a parasitic capacitor formed between a sensor line connected to a touch sensor pad and other signal line and provides a stable sensor output. A sensor line connected to a touch sensor pad is connected to a non-inverting input terminal (+) of a charge amplifier. An LED is disposed in the touch sensor pad, and the cathode of the LED is connected to an LED signal line. Since the LED signal line is disposed adjacent to the sensor line, a parasitic capacitor is formed between the LED signal line and the sensor line. In order to keep the capacitance of this parasitic capacitor constant, a pull-up resistor is connected to the LED signal line. The LED signal line is biased to a power supply potential Vdd by the pull-up resistor.