光音響効果を用いた内部欠陥検出の自動化に関する研究

Abstract

A non-contact and non destractive internal defect could be detected by a low power semiconductor laser and a ultrasonic sensor using a photoacoustic effect. But the sensitivity of the ultrasonic sensor is low for detecting the photoacoustic signal. To detect the photoacoustic signal, a self-coupling effect of another semiconductor laser was used. The self-coupling sensor has high spatial resolution in comparison with the ultrasonic sensor. It takes a lot of time to detect detail defect profile manually. Then an automatic of internal defect detection by photoacoustic effect has been studied, in which X-Y auto stage and oscilloscope are connected to personal computer. It is found that by automatic measurement in defect detection the detective sensitivity becomes to be high and the processing time becomes to be short.