超低ヒステリシス特性を有するQCR荷重センサ

抄録

This paper presented the quartz crystal resonator (QCR) force sensor with the ultra-low loading hysteresis that originally had the high force sensitivity, the high dynamic range, and the high rigidity at a time. The loading hysteresis was a critical issue for the previous QCR force sensor which contained the thin polymer-based bonding layer. Since the plasto-viscoelastic deformation of the bonding layer was contributed to the residual stress and the strain of the QCR, the QCR force sensor did not exhibit the high static reproducibility. To solve this issue, we employed the direct hydroxyl bonding method of the quartz crystal surfaces that had essentially low plastic deformation. To endure high loading force to the QCR, we elucidated the preferable process of the hydroxyl bonding by means of the atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The result indicated that a certain sequence of the surface cleaning process exhibited the bare flat SiO2 surface, and the plasma activation process increased the high amount of the surface hydroxide, resulting in the high bonding strength. Finally, the proposed QCR force sensor exhibited the quite low loading hysteresis of less than one tenth for the demonstration of the mass sensor.