| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus and method for inspecting laser ultrasonic wave improving the distance resolution in the case of deciding a defect position while the conventional advantages are maintained as they are. SOLUTION: A rotating mechanism 30 is to alter the angle of the inclination in the direction of an arrow of a specimen 16. When the specimen 16 is inclined, the light diffracted by a diffraction grating 15 is cast on the specimen 16 at a certain angle. When the specimen 16 is inclined to the central axis of a laser beam, the upper part of the specimen 16 approaches the grating 15, and the lower part of the specimen 16 separates from the grating 15. The pitch of the interference fringes generated on the surface of the specimen 16 is short at the upper apart and long at the lower part. The waveform of the wave generated by such a laser beam becomes a chirp waveform. |
