Miniaturization and resolution improvement of load sensor using AT-cut quartz crystal resonator

A compact load sensor we developed uses an AT-cut quartz crystal resonator whose resonance frequency changes under external load, and features high sensitivity, high-speed response, and a wide measurement range. 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 load measurement because of low degree of mechanical characteristic, that is, it is weak to stress concentration by bending. We have developed and characterized a sensor mechanism that safely maintains the quartz crystal resonator. The objective of this study is to improve the resolution of load measurement and to miniaturize the sensor. We designed a novel retention mechanism of the quartz crystal resonator which is fixed vertical to the applied load. The new load sensor was evaluated on the relation between load and resonance frequency as well as temperature and resonance frequency.