Using artifact suppression OCT based on polarization multiplexing for tomographic imaging of LCD screens

Defect detection in the inner layers of liquid crystal display (LCD) panels is crucial for the quality control of displays. Optical coherence tomography (OCT), a nondestructive, high-resolution tomographic imaging technique, has been applied in the inspection of display panels. However, the artifacts that arise in imaging multilayer samples remain a challenge. In this study, we propose and validate a method for artifact removal in coherent imaging of multilayer refractive samples. These samples exhibit complex autocorrelation artifacts due to self-interference and multiple reflections. Two orthogonally polarized reference beams with fixed phase shifts, combined with the proposed algorithm, are employed to suppress the autocorrelation in the sample light path. To address the issue of mirror artifacts caused by real spectrum signals, the intensity ratio of the two orthogonally polarized reference beams is adjusted, allowing distinction between real signals and mirror artifacts, thus achieving full-range imaging. Experiments were conducted to measure 3D images of multilayer quartz glass sheets, inclined ceramic blocks, and LCD panels, validating the reliability of the proposed approach and demonstrating its advantages in display defect detection.