摘要 |
An apparatus for surface inspection according to the invention comprises an irradiating optical system for throwing an irradiating light beam from a light source onto the surface of an object of inspection, a light receiving optical system for receiving a scattered light beam reflected from the surface of the object of inspection irradiated by the irradiating optical system, a photosensing portion for forming a surface data signal from the scattered light beam received by the light receiving optical system, a displacement portion for displacing the surface of the object of inspection relative to the irradiating optical system, plus the light receiving optical system, continuously in the main scanning direction and intermittently in the sub-scanning direction, and a foreign matter detecting portion for detecting a foreign matter present on the surface of the object of inspection on the basis of the maximum value level of the surface data signal and obtaining the position, in the sub-scanning direction, of the foreign matter present on the surface of the object of inspection on the basis of at least two adjoining surface data signals in the sub-scanning direction.
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