METHOD AND APPARATUS FOR OPTICAL INSPECTION OF DEFECT IN TRANSLUCENT SHEET-LIKE MATERIAL

• Main Authors: TODA MASATOSHI, KADOSAWA FUMIO
• Format: Patent
• Language: English
• Published: 06.01.1998
• Edition: 6
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To detect defects in a light translucent sheet-like material at high precision. SOLUTION: Illuminating light having directivity in the main surfaces are radiated to end faces 6a, 6b of a light translucent sheet-like material 2, which has a pair of mutually parallel main surfaces 4a, by illuminating means 12a, 12b to transmit the illuminating light on the inside of the sheet-like material 2 due to the reflection by the inner faces of the pair of the main surfaces and the coming out light whose optical path is deflected by a defect existing in the sheet-like material 2 and which comes out of the pair of the main surfaces 4a is detected to optically detect the defect in the light transmissive sheet-like material 2. In this case, the illuminating light having directivity in the direction inclining to the end faces 6a, 6b of the sheet-like material 2 is radiated at incident angle θ and the defect detecting position 30 is detected by employing image pick-up means 20A, 20B, 22A, 22B, 24A, 24B installed in the direction inclining to the normal line direction of the main surfaces 4a.