Design, fabrication and characterization of compact force sensor using AT-cut quartz crystal resonators

A compact force sensor with the AT-cut quartz crystal resonator was developed. The quartz crystal resonator has the characteristic that the resonance frequency changes by the external force, which achieves high sensitivity, high-speed response, and wide range of measurement by a simple structure. Also it has the superior feature in the temperature and frequency stability. In the past, the quartz crystal resonator had been hardly applied to the force measurement because of low degree of mechanical characteristic, that is, it is weak to stress concentration by bending. The objective of this study is to construct the sensor mechanism that safely maintains the quartz crystal resonator for the external force with flat structure. We designed and analyzed a novel retention mechanism of the quartz crystal resonator. The proposed force sensor is flat, small, and sensitive. It can be applied to several usages such as medical treatment and contact force detection of human.