Dome shaped touch sensor using PZT thin film made by hydrothermal method

We propose a dome shaped touch sensor unit, which is small and is applicable in high temperature environment. The PZT thin film was made on the half-round Ti substrate, and the electrodes were deposited on its surface to form the sensor and driving actuator. The PZT thin film was made on the curved surface of the substrate by the hydrothermal method. The actuator part is driven by the high frequency voltage at the resonant frequency of 6.2 kHz and the sensing part can detect the impedance change before and after the contact. The sensor works with the low voltage (5 V). It works under the high temperature (over 50/spl deg/C). The structure is simple and easy to miniaturize. This sensor can be used as the control touch-pad of the car instead of the conventional capacitive type computer touch pad, because it can resist high temperature and disturbance from the electrostatic inductance change. The basic property of the sensor is shown.