| 摘要 |
PROBLEM TO BE SOLVED: To increase the amplitude at an overtone frequency region by specifying mean surface roughness of both front and rear major sides of a piezoelectric single crystal substrate and end faces in the lengthwise direction and selecting a vibration electrode width smaller than the substrate width of the piezoelectric single crystal substrate. SOLUTION: Vibration electrodes 2, 3 whose major components are Ag and Cr are bonded to both front and rear major sides of a piezoelectric single crystal substrate 1 made of a paper-tablet lithium tantalate or the like with the thin film technology such as vapor deposition. The mean surface roughness Ra of both the front and rear major sides of the piezoelectric single crystal substrate 1 is selected to be 0.2μm or below and the mean surface roughness Ra of end faces in the lengthwise direction is selected to be 0.5μm or below and the electrode width of the vibration electrodes 2, 3 is selected smaller than the width of the piezoelectric single crystal substrate 1 to expose the surface of the piezoelectric single crystal substrate 1 around the vibration electrodes 2, 3 with a width of 0.1mm. Since the disturbance of the vibration is suppressed on the major sides and irregular reflection of the generated vibration is effectively suppressed on the side faces, high order overtone oscillation of 3rd-degree and 5th-degree or over is stably executed.
|
