| 摘要 |
PURPOSE:To widen an inspection range per channel, by arranging a transmission light diffracting/scattering plate on the front of a columnar photoconductor and reflectors on the back thereof and on the other end face thereof respectively. CONSTITUTION:Light reflected on the surface of material 1 to be inspected is incident into a transmission light diffracting/scattering plate 7. Here, as the plate 7 is provided with a linear mark 7-1, the incident light is scattered evenly on a plane passing an axis of a columnar photoconductor 8. A part of the light incident into the columnar photoconductor 8 passes therethrough intact while the other thereof reaches at a photomultiplier tube 11 reflecting in multiplicity on the internal surface thereof to detect. Light partially transmitted is made incident again into the columnar photoconductor 8 with a reflecting object 9 provided on the back of the columnar photoconductor 8. The light propagated to the reflecting object 10 at the other end face of the columnar photoconductor 8 is reflected toward a photomultiplier tube 10 thereby achieving a compensation for an attenuation which grows as the light separates from the photomultiplier tube 10. |
