APPARATUS FOR DISCRIMINATING DEFECTS IN AN OPTICAL RECORDING MEDIUM AND METHOD THEREOF

摘要

An apparatus for discriminating defects on the surface of an optical recording medium such as an optical memory card and a method thereof. According to the method of discriminating defects in the optical recording medium, the light is projected at a predetermined tilted angle onto the surface of a transparent protection film formed on the surface of the optical recording medium on which the pattern of optical change is formed to record data, and the surface of the protection film is photographed by a TV camera to discriminate any defect on the protection surface. The apparatus for practising this method comprises a plate on which the optical recording medium is placed, a TV camera for photographing the surface of the optical recording medium, a picture tube unit for receiving the picture of the TV camera, and a source of light for dark field illumination that projects the ray of light onto the surface of the optical recording medium at a predetermined angle. On the TV camera are projected defects only such as stains and scars adhered to the optical recording medium without affected by light reflected from the surface of the protection film, and defects are discriminated very easily.