| 摘要 |
PURPOSE:To reduce the intensity of an electric field in the edge part of a piezoelectric oscillator to suppress edge waves, by constituting the piezoelectric oscillator so that its acoustic medium-side electrode is not extended to the edge part in the lengthwise direction of the piezoelectric oscillator. CONSTITUTION:A piezoelectric oscillator 20a consists of piezoelectric materials such as PZT and is constituted so as to be rectangular in top and side views and be trapezoidal in the front view, and an electrode 21a on the upper face is used as the acoustic medium-side electrode and is smaller than an electrode 22 on the lower face at the view from the acoustic medium side and is not extended to edge parts of the piezoelectric oscillator 20a. Both edge parts of an ultrasonic probe in the lengthwise direction are cut obliquely so that the electrode 21a on the upper face is not extended to edge parts. As the result, the occurrence of the disorder of the dielectric flux density in edge parts, the transverse effect of electromechanical coupling of piezoelectric materials, etc. which cause the generation of edge waves are prevented, and the intensity of the electric field in edge parts is reduced to suppress the generation of edge waves. |
