Patent ID: 6538729
Filing Date: 2003-03-25
Classification: G01N

Abstract:
A unit for inspecting a surface, which is utilized in inspecting a flaw generated on a specular surface to be inspected or in reading a carved mark on a specular surface to be inspected, characterized by that an illuminating means having a point illuminating element as a point light source or close to a point light source, a Fresnel lens, a half mirror and an image capturing means are supported by a body, wherein light is irradiated from the illuminating means, the light is refracted by the Fresnel lens so as to converge in a condition of being close to parallel, the refracted light by the Fresnel lens is reflected against the half mirror, the reflected light is irradiated on generally whole area of the surface to be inspected and the reflected light is introduced into the image capturing means provided at a position where the light converges, wherein the illuminating means is provided to move along an optical axis of the light irradiated from the illuminating means.