Abstract: The image pick-up device picks up an image of the inspection target optical member whenever it rotates a predetermined angle. The image data which is output by the image pick-up device picking-up the image undergoes coordinate transformation from polar coordinate system to rectangular coordinate system and thereafter binarization process. The area of the defective candidate objects which are extracted from the image data in two color system obtained through the binarization process are normalized in accordance with the reference values prepared for each region in which said defective candidate objects formed within the image data. The points which are calculated as a result of this normalization, are added to the corresponding columns in the classification table. It is judged whether the inspection target optical member is satisfactory or not, in accordance with whether or not evaluation function calculated on the basis of the value in each column exceeds a predetermined reference value.

Abstract: A holder is constructed of a cylindrical member made of a metal and an inward flange member made of a diffusion transparent member. The inside of the cylindrical member is sectioned into a tapered area whose inside diameter decreases downward, and a small-diameter cylindrical area and a large-diameter cylindrical area. The inward flange member is bonded to the bottom end of the small-diameter cylindrical area.

Abstract: An optical member inspection apparatus is disclosed. A light shielding plate functions to cast a shadow region so that a line sensor receives an image producing a particular defined image data output, generally speaking a dark image representing an absence of light from an illuminator. When an inspection target optical member is inserted in the light path to intersect that shadow region, the line sensor produces the same image data in the event that there is no defect in the optical member. However, a defect in the optical member will enable light from outside that shadow region to be diffused to impinge on the line sensor thereby producing a change in the image data output. Evaluation of the change in the image data output can provide an indication of the degree of defectiveness.