Abstract
A multifunctional MEMS sensor for measurement of proximity and touch of an object has been fabricated and characterized. The DC resistance changes linearly to indentation distance of the object. On the other hand, the AC (> 500 kHz) impedance increases with increase of distance between the sensor surface and the object because of decrease of light intensity reflected on the object surface. An error of proximity measurement induced by environmental temperature and illuminance has been characterized. The error was estimated at 1 mm for 1℃ temperature change and at 2 mm for 500 lx illuminance change, respectively, and they are enough low in stable environment. Moreover, the AC impedance was different between grounding and floating the proximate object because of difference of distribution of electricstatic field between electrodes, so that it is suggested that proximity can be measured as the impedance change by light as well as electrostatic field.
