Sliding position detection of touchscreen with piezoelectric cantilever

In this study, a 1-D piezoelectric touchscreen that can provide the capability of touch position and sliding movement detection is proposed. To overcome the output voltage decay issue due to the capacitive behaviors of piezoelectric materials, a proposed sliding analysis approach was developed to implement the touch position detection. A structure of two piezoelectric cantilevers embedded on two ends of a beam was employed, in which one of the cantilevers serves as an actuator and the other a sensor. With the vibration provided by one of the piezoelectric cantilevers on the beam, the other would generate a corresponding voltage. According to the comparison of phase delays between the input and the generated voltage of the two piezoelectric cantilevers, the applied position of external static loading is estimated. Thus, the voltage decay issue of the general piezoelectric sensor can be efficiently solved, and the sliding movement can also be detected. From the experimental results, the proposed 1-D piezoelectric touchscreen can be demonstrated to detect sliding movement in real-Time within 2∼5mm position detection error at sliding velocity of 9mm/s.