Noncontact ultrasonic imaging of subsurface defects using a laser-ultrasonic technique was demonstrated. Pulsed laser irradiation was used for ultrasonic generation, and optical heterodyne interferometry was used for detection of ultrasonic vibration on the specimen surface. Bonded thin plates with character-shaped hallmarks with 1.5mm width on bonding layer were used as specimens. Imagings in ultrasonic transmission and reflection modes were performed, and imagings using not only XY-scanning of specimens but also a laser beam scanner were demonstrated. Ultrasonic images of hallmarks located 0.2mm below the specimen surface were obtained through the experiments.
|ジャーナル||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|出版ステータス||Published - 1996|
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