利用反射率(或透射率)的大小变化来控制膜层厚度是真空镀膜工艺中常用的一种方法。虽然反射率可用数字计算或作图法求得,但由反射率计算出仪表的指示数仍然是件麻烦的工作,本文将用“反射率—仪表读数”曲线图来解决这个困难。首先考虑反射控制法。采用平板玻璃作为控制片时,光线在平板玻璃内产生多次反射(图1)。R_0为玻璃没有镀膜时表面的反射率, Controlling film thickness by the change of reflectance (or transmittance) is a commonly used method in vacuum coating. Although reflectivity can be calculated numerically or plotted, calculating the gauge reading from reflectivity is still a cumbersome task. This article will use the Reflectance-Meter Reading chart to solve this difficulty. First consider the reflection control method. When flat glass is used as a control sheet, the light produces multiple reflections within the flat glass (Figure 1). R_0 is the reflectivity of the surface of the glass without coating,