Compact Force Sensor Using AT-Cut Quartz Crystal Resonator Supported by Novel Retention Mechanism

The compact force sensor we developed uses an AT-cut quartz crystal resonator whose resonance frequency changes under external force, and features high sensitivity, high-speed response, a wide measurement range, and superior temperature and frequency stability. Quartz crystal resonators were rarely used in force measurement due to their poor stress concentration during bending. The objective of this study was to construct a sensor mechanism that safely maintains the quartz crystal resonator under external force. We designed and analyzed the novel retention mechanism of the quartz crystal resonator. The proposed structure is flat, small, and sensitive. Moreover, we designed and produced a compact case for mounting the retention mechanism. Sensor output is expected to be changed by thermal expansion, so we evaluated the temperature characteristics of the assembled sensor, finding the relationship of the temperature and sensor output to be linear and temperature easily compensated for.