Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography

TLDR

An application of spectral domain optical coherence tomography (SD‑OCT) was demonstrated for fast industrial inspection of an optical thin film panel, using two identical SD‑OCT systems for parallel scanning and dual inspection heads for transverse scanning with a motorized stage for lateral scanning, enabling cross‑sectional and volumetric imaging to detect defects. The rapid inspection enabled early detection of product defects on the manufacturing line, significantly improving quality assurance of industrial products.

Abstract

An application of spectral domain optical coherence tomography (SD-OCT) was demonstrated for a fast industrial inspection of an optical thin film panel. An optical thin film sample similar to a liquid crystal display (LCD) panel was examined. Two identical SD-OCT systems were utilized for parallel scanning of a complete sample in half time. Dual OCT inspection heads were utilized for transverse (fast) scanning, while a stable linear motorized translational stage was used for lateral (slow) scanning. The cross-sectional and volumetric images of an optical thin film sample were acquired to detect the defects in glass and other layers that are difficult to observe using visual inspection methods. The rapid inspection enabled by this setup led to the early detection of product defects on the manufacturing line, resulting in a significant improvement in the quality assurance of industrial products.