Optical Module for Distinguishing Real and Fake Cracks in LCD and OLED Glass Boards

Abstract

We developed an optical module for distinguishing true and fake cracks in LCD and OLED glass board conveyer. We used a pulse modulated infrared laser to improve the functionality of distinguishing true and fake cracks formed at the edges of glass board. The conventional optical detection algorism sensing real cracks modified to reduce any misinformation of fake crack for true crack. We discussed the optimum operational conditions as functions of pulse modulation frequency and wavelength of the laser, transport speed of glass board, spot size and working distance of a focused laser beam.

Laser Inspection for Distinguishing Real Crack from Suspected Defects of Glass Boards

“…The optical inspection module especially provides the preliminary process before the main product processes. Many optical methods have been tried to inspect micro-cracks in silicon wafer [1][2][3][4][5] , optical substrate 6,7 , metal surface 8 and others where difficult to use direct inspection [9][10][11] . The other conventional inspection method of vision system with CCTV could have not offered an expected test error rate due to its insufficient accuracy.…”