| 摘要 |
PURPOSE:To accurately detect the flaw of a planar body having a large inspection width by a simple means, by positively scattering the reflected or transmitted light from the planar body at the time of optical scanning by a scattering member and allowing the scattering light to be incident to a light transmitting member. CONSTITUTION:The light source 12 of a light irradiating system 11 comprises a laser diode or a light emitting diode and the surface of a planar body 41 is optically scanned by an optical scanner 15 such as a rotary mirror. Corresponding to a reflected or transmitted light receiving region due to the planar body 41, a scattering member 25 and the light incident part of the light transmitting member 21 are relatively arranged on front and rear sides, and the light emitting part of the light transmitting member 21 and a light receiving detection system 31 are preliminarily connected to each other. Then, reflected or transmitted light generated when the surface of the planar body 41 is optically scanned by the light irradiating system 11 is scattered by the scattering member 25 to be incident on the light transmitting member 21 from the light incident part and the incident light is allowed to be incident on the light receiving detection system 31 from the light emitting part and the flaw of the planar body 41 is detected on the basis of the change in a light receiving level. |
