Patent ID: 7408633
Filing Date: 2008-08-05
Classification: G01N

Abstract:
1. A defect inspection apparatus for detecting defects of a retardation film while said film is being conveyed continuously in a transport direction, said apparatus comprising: a light source for projecting light onto a surface of said film; a light receiver placed on an opposite side of said film to said light source, said light receiver receiving light projected from said light source and transmitted through said film, to output photoelectric signal corresponding to the received light; and a judging device for judging based on the photoelectric signal from said light receiver as to whether there is a defect in said film or not, wherein said light receiver is positioned to satisfy the following conditions: wherein θ 1 represents an angle formed between an optical axis of said light receiver and a normal line that is perpendicular to the surface of said film, and θ 2 represents a rotational angle of said optical axis to said transport direction, as rotated about said normal line.