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

Area of Science:

• Optical Engineering
• Metrology
• Materials Science

Background:

• Defect detection in liquid crystal display (LCD) panels is critical for quality control.
• Optical coherence tomography (OCT) is a high-resolution imaging technique used for display panel inspection.
• Artifacts in OCT imaging of multilayer samples hinder accurate defect detection.

Purpose of the Study:

• To propose and validate a novel method for artifact removal in coherent imaging of multilayer refractive samples.
• To enhance the reliability of defect detection in LCD panels using OCT.

Main Methods:

• Utilized two orthogonally polarized reference beams with fixed phase shifts to suppress autocorrelation artifacts.
• Developed an algorithm combined with adjustable intensity ratios of reference beams to distinguish real signals from mirror artifacts.
• Achieved full-range imaging for multilayer samples.

Main Results:

• Successfully suppressed complex autocorrelation artifacts arising from self-interference and multiple reflections in multilayer samples.
• Demonstrated the ability to distinguish real signals from mirror artifacts, enabling full-range imaging.
• Validated the approach through 3D imaging of quartz glass, ceramic blocks, and LCD panels.

Conclusions:

• The proposed artifact removal method significantly improves the reliability of OCT for inspecting multilayer structures.
• This technique offers advantages for defect detection in LCD panels, enhancing quality control processes.
• The validated approach provides a robust solution for overcoming imaging challenges in multilayer refractive samples.