| 摘要 |
PURPOSE:To detect the defect in a painted film nondestructively and readily, by periodically emitting light to the painted film, and detecting elastic waves generated on the film. CONSTITUTION:The light emitted from a xenon lamp 24 is intermittently projected on a measuring cell 16 by way of a condenser lens 12, an interference filter 26, and a light chopper 28. Elastic waves generated by the expansion and contraction of a painted film are detected by a microphone 34 and inputted to a lock in amplifier 20. The input signal from the microphone 34 is turned with the signal from a photocoupler 36, which is synchronized with the light chopper 28, and amplified by the amplifier 20. The result is displayed on a recorder 22. Thus the defects in the painted film are readily detected nondestructively. |
