Patent ID: 6697513
Filing Date: 2004-02-24
Classification: G01M

Abstract:
An optical member inspection apparatus comprising:a light source; a diffuser, for diffusing light rays emitted from said light source, comprising a central portion and a peripheral portion, wherein a diffusion transmittance of said peripheral portion is higher than a diffusion transmittance of said central portion so that high luminance light rays are emitted from said peripheral portion, and low luminance light rays are emitted from said central portion; an image pick-up that forms an image of an optical member to be inspected by only utilizing light rays emitted from said central portion of said diffuser; a device for moving said light source, with respect to said diffuser, in a direction along an optical axis of said image pick-up so that the ability to detect an absorptive defect and the ability to detect a scatterable defect are varied; and a processor for receiving image signals output from said image pick-up and determining whether said optical member is defective based on said image signals; wherein said diffuser is immovably mounted on said optical member inspection apparatus so that said diffuser is positioned on a plane perpendicular to said optical axis of said image pick-up; wherein among said high luminance light rays, only high luminance light rays that are inclined relative to the optical axis of said image pick-up are incident on said optical member to be inspected; and wherein said inclined high luminance light rays are incident on an area of said image pick-up where said image of said optical member to be inspected is formed, only when said inclined high luminance light rays are incident on said scatterable defect of said optical member to be inspected.