| 摘要 |
PURPOSE: To provide an ultrasonic inspection apparatus by which ultrasonic waves can be generated inside a sample from a sufficiently separated distance from the sample as an inspection object and by which the ultrasonic waves can be detected simultaneously in a noncontact manner and with high sensitivity. CONSTITUTION: A laser beam 16 composed of a pulse train is emitted to a sample 17, it generates ultrasonic waves at the inside, and a part of them is used as a reference signal 21 by a photodetection part 20. An ultrasonic pulse train which is generated inside the sample is detected when the Doppler shift to which a laser beam 31 for a probe is subjected is captured by the Fabry-Perot interferometer 34. The pulse signal of the reference signal 21 and the ultrasonic pulse train inside the sample have high correlativity. As a result, when a detection signal 36 is correlation-processed by using the reference signal 21 in a correlation processing part 40, the high S/N ratio of a correlation signal 41 can be realized, and a flaw at the inside of the sample can be inspected with high accuracy. |
