Ultrahigh-precision 3D-shape measurement technique usable under vertical vibration

本文研究了一种利用激光测量光程差（OPD）纳米级变化的新技术。该技术可以实时、高速地测量垂直扫描干涉显微镜的视差。有了这项技术，我们可以在预定的相位变化后触发LED闪烁和干涉图曝光，即使在垂直振动下也是如此。对该技术测量的三维形状进行了分析，结果表明，为了实现更高精度的形状测量，必须纠正暴露过程中振动的影响。然后，我们开发了另一种技术，可以从振动影响的干涉图强度和曝光过程中OPD变化的历史中提取曝光开始时刻的干涉相位。利用垂直扫描干涉显微镜进行了脉冲振动实验，验证了该方法的有效性。

We have developed a new measurement technique for nm-level change of an optical-path-deference(OPD) using laser. This technique can measure OPD of a vertical-scan interference microscope real time and high speed. With the technique we can trigger LED flashings and interferogram exposures right after predefined phase changes even under vertical vibrations. Analyzing the measured 3D-shape obtained with the technique results in that affects of vibration during the exposure should be corrected for higher precision shape measurement. Then we have developed another technique which can extract interference phase just on the exposure-start moment from vibration-affected interferogram intensities and history of OPD changes during the exposure. Validity of the developed technique is proved by experiments using the vertical-scan interference microscope with intentionally generated pulse-like vibration.