| 摘要 |
PURPOSE:To make the diagonal incidence of sound waves to an object to be examined easy and to permit good observation of the internal part of the object by picking up images by making use of an ultrasonic wave transducer having interdigital electrodes. CONSTITUTION:Interdigital electrodes 3, 4 for inputting and outputting which are spaced from each other are provided to the piezoelectric susbtrate 2 of an ultrasonic wave transducer 1, and are coupled acoustically to an object 6 to be examined through a liquid material 5 such as silicone oil. Now when an AC electric signal is applied to the electrode 3, a longitudinal sound wave L1 propagates in the liquid at an incident angle theta1, and in the place of the object 6 said wave is converted to a bulk wave L2 which enters the inside of said object at an incident angle theta2. The wave reflects on a discontinuous part 6a such as a flaw and is outputted to the electrode 4. If there are no flaws, the wave is reflected on the bottom surface. According to the presence or absence of any flaw, a difference arises in the length of the propagation path and acoustic images are obtained by the different delay outputs. Therefore the diagonal incidence of the sound waves is made easy and the internal images are observed satisfactorily. |
