| 摘要 |
PURPOSE:To detect the change in the heat generating temp. of an ultrasonic transducer and to suppress the generation of heat of the ultrasonic transducer itself, by providing a current detector to the output part of an ultrasonic transducer driving means and detecting the impedance change of the transducer from a detected current. CONSTITUTION:When the value of impedance detected through the comparison with the threshold value of impedance set from the relation between the impedance of a transducer and temp. in a threshold value judge circuit 18 is lower than a threshold value (x), a transducer 14 is judged to be heated and the transistor Q of a control means 12, for example, an electric field effect transistor thereof is driven to stop the operation of a pulse generator 7 and that of a low frequency oscillator 8. By this constitution, a driving pulse and a low frequency signal are not supplied to the ultrasonic transducer 14 and the operation of the ultrasonic transducer 14 is stopped to make it possible to suppress the generation of heat of said transducer. |
