A PROCESS AND DEVICE FOR TESTING TRANSPARENT MATERIAL SHEETS

摘要

The tester has a laser beam or similar light beam swept across the plate glass as the latter travels past during manufacture. Light reflected from impuritles (such as air bubblers, microstones etc) and other defects are detected by a photodetecter whose elec. output is evalvated. Light travelling accros the moving glass is detected and converted into elec. pulses during each sweep across the glass. A reference strip made of the same material as the glass being examined is scanned by an auxiliary light beam.