| 摘要 |
PURPOSE:To off two-frequency probe having a wide frequency band width on the high frequency side as compared with a convensional two-frequency probe by combining an oscillator having laminated structure to be used for two frequency bands through the frequency band width on the high frequency side is narrow and a normal single- frequency oscillator having a wide frequency band characteristics. CONSTITUTION:The oscillator consists of a piezo-electric ceramic plate 10 forming electrodes 11, 12 on both sides and a plate material 13 jointed with a part e.g. the center part, of the rear face (opposite to an ultrasonic wave transmitting/receiving face) of the plate 10. The plate material 13 is made of a material whose acoustic impedance is practically equal to that of the plate 10 and the same material as the ceramic plate 10 is typically used for the plate material 13 In this configuration, an area (1st oscillator) having the laminated structure with which the plate material 13 is joined and an area (2nd oscillator) having no join with the plate material 13 or having thin thickness act as respectively individual oscillators. Since the high frequency side narrow band characteristics of the 1st oscillator is compensated by the 2nd oscillator, a two-frequency probe having a wide frequency band width on the high frequency side as a whole can be obtained. |
