| 摘要 |
PURPOSE:To decrease resonance impedance and to drive a sensor at high efficiency by providing a constitution wherein the length of one side of the junction plane between an elastic bonding member and a driving piezoelectric element in the thickness direction is 30 - 70% the length of the other side in the direction of the width. CONSTITUTION:Driving piezoelectric elements 2 and detecting piezoelectric elements 1 are connected through bonding members 3 in the orthogonally intersecting pattern. Thus the orthogonally intersected sensor elements are formed. A pair of the elements are bonded at the end parts of the piezoelectric elements 2 with an elastic bonding member 4. Thus a sensor is formed as a tuning fork. The length corresponding to the thickness direction of a contact plane 11 between the bonding member 4 and the piezoelectric elements 2, i.e. the depth for holding the piezoelectric element 2, is denoted as (a). The length in the width direction, i.e. the other side of the holding surface is denoted as (b). When the ratio a/b is small, i.e. the thickness direction (holding depth) is small, the holding becomes unstable. When the ratio a/b is too large, i.e. the thickness direction (holding depth) is large, the holding area is too large, and the oscillation of the piezoelectric element 2 is suppressed. Thus resonance impedance becomes high. The optimum condition exists at the intermediate part. When a/b is 30 - 70%, the resonance impedance becomes about 30kOMEGA and less, and the stable characteristic is obtained. |
