Utilization of a complex-valued interference signal (CVIS) in a white-light scanning interferometer is a powerful method to measure exactly surface positions of a glass plate. In this method a zero phase position nearest to a maximum amplitude position in the CVIS is a measured surface position. Proportional coefficients that relate the maximum amplitude position and the zero phase position of a rear surface to the thickness of a glass plate are required for measuring exactly the thickness. These coefficients and periodical position jump occurring on the zero phase position are investigated by simulations. The number of occurrences of the position jump is calculated from the maximum amplitude and zero phase positions. Shape measurement of a glass plate with about 20 μm-thickness is achieved by using the coefficients and the number of occurrences of the position jump.

在白光扫描干涉仪中利用复数值干涉信号（CVIS）是一种精确测量玻璃板表面位置的有效方法。在该方法中，最接近CVIS中最大振幅位置的零相位位置是测量的表面位置。为了精确地测量厚度，需要将后表面的最大振幅位置和零相位位置与玻璃板的厚度相关联的比例系数。通过仿真研究了在零相位位置上发生的这些系数和周期性位置跳变。根据最大振幅和零相位位置计算位置跳变的次数。