| 摘要 |
PURPOSE:To obtain a device having a high sensitivity in which a signal-to-noise ratio is improved, by placing a sensor part so as to detect a scattered light which is propagated through the inside of an object to be inspected, by repeating a total reflection, and emitted to the outside of the object to be inspected, from the side face of the object to be inspected, in the lights which have been scattered by a defect existing in the object to be inspected. CONSTITUTION:A beam-shaped light 3 which is emitted from a laser light source 8 is condensed onto the surface of an object to be inspected 1 by a condensing lens 9, and the surface of the object to be inspected 1 is scanned two- dimensionally by a scanning means 10. In case when a defect 5 exists in the object 1 to be inspected the rays of light 3 are scattered by the defect 5, propagated through the inner surface of the object to be inspected, and detected by a sensor part which is placed so as to receive a side face scattered light 6 emitted from the side face. For instance, a photoelectric multiplier tube is used as a condensing means 11 of a sensor part 7 in the scanning means 10, and an optical fiber bundle, an optical sensor 12, respectively. |
