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

我们发展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OPD。有了这项技术，即使在垂直振动下，我们也可以在预定义的相位变化后立即触发LED闪光和干涉图曝光。对测量得到的三维面形进行了分析，结果表明，为了获得更高精度的面形测量，需要对曝光过程中的振动影响进行校正。然后，我们开发了另一种技术，该技术可以从曝光过程中受振动影响的干涉图强度和OPD变化历史中提取出仅在曝光开始时刻的干涉相位。利用故意产生脉冲式振动的垂直扫描干涉显微镜进行了实验，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.