SURFACE DEFECT MEASURING APPARATUS

摘要

PURPOSE:To enable accurate measurement on the presence of any surface defect of an object to be measured by monitoring reflected lights from the surface thereof and beam passing the surface thereof when a light beam varying in the optical axis is irradiated on the surface and side of the object being measured. CONSTITUTION:A light beam from a laser 16 is irradiated on the surface and the side of work 14 supported movably according to the rotation of a scanner 18. The beam reflected from the surface of the work 14 is incident into a detector 32 while the beam passing the surface thereof into a detector 38. Judgment can be done as follows: A foreign matter is attached to the surface of the work when the reflection signal VS differs from the reference level while the side passage signal VP does from another reference level; any defect develops on the surface thereof 14 when the reflection signal VS differs from the reference level while the side passage signal VP coincides with the reference level; and the work should be accepted when the output signals VS and VP coincide with the corresponding reference levels.