基于偏振OCT的高分辨率激光焊接检测技术研究

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中图分类号：TN247文献标志码：A

Abstract： The optical coherence tomography （OCT）-based laser welding inspection technique enables direct measurement of keyhole depth and weld seam surface morphology， but multiplereflection artifacts reduce the accuracy of OCT-based welding inspection. By utilizing polarization sensitive OCT to detect changes in the polarization state of backscattered light， it is possible to mitigate the effects of multiple reflections in laser welding inspection， thereby enhancing the accuracy of inspection. This research utilized a light source with a broader spectral bandwidth， coupled with an optimized spectrometer design， to enhance the system's axial resolution while simultaneously reducing the decay of sensitivity with depth. This study analyzed the relevant parameters affecting the performance of spectrometer in the polarization sensitive OCT system and optimized the design of the spectrometer accordingly. The design of a high resolution， low lateral chromatic aberration spectrometer was achieved by using a deformed Huygens eyepiece structure type focusing mirror set to optimize the image plane chromatic dispersion spot. Experimental results showed that the axial resolution of the H and V channels had been increased from 10.2μm and 10.5μm to 4.58μm and 4.30μm respectively. In the keyhole imaging experiments， this technique eliminates multiple reflection artifacts and aligns the accurate structure of the keyhole sample. In addition， this technique is also suitable for laser welding defect inspection.

Keywords： laser welding inspection; optical coherence tomography; spectrometer; polarization state

激光焊接技术具有效率高、变形小、热影响区域小等特点，已被广泛应用于机械工程[1]、汽车工程[2]等领域。（剩余14669字）