Quartz Crystal Resonator Force Sensor combined with the high-efficiency stress concentration mechanism

Abstract

This paper proposed a new technique to implement the pasted-type QCR force sensor onto the elastic hinge structure. The technique utilized a slit structure on the center of the metal elastic hinge, resulting in the high efficiency of the stress concentration. QCR force sensor was fabricated as a rectangular shape so that the bridge shaped bonding was possible across the slit structure. The stress concentration effect was examined by using the FEM technique that suggested the uniform stress concentration at the oscillatory region of the QCR. The geometrical effect of the slit structure was also examined. The result suggested that the width of the slit dramatically decrease the hinge rigidity. Therefore, the optimal width is important to keep the structural rigidity and the force sensitivity at a high criteria. Finally, we compared the force sensitivity by loading the 100g weight to the device, resulting in the force to frequency sensitivity as 193062 Hz for the tensile sensor and 283809 Hz at the compressive sensor. The sensitivity was improved over 20 times compared with the one we previously reposted.