表面粗糙度干涉仪中光探针的自动聚焦控制

Automatic Focusing of Light Probe in Interferometer for Measuring Surface Roughness

要保证测量光聚焦在待测表面，自动聚焦控制是非常重要的。文中给出了基于离焦检测的自动聚焦控制原理和技术实现，其聚焦灵敏度达０．１μｍ，聚焦范围０．５ｍｍ，频带宽度为４０Ｈｚ。它为表面粗糙度干涉仪的高分辩率测量提供了保证，并为实验所证实。该技术具有很强的实用开发价值。

To keep the measurement light focusing on the measured surface , an automatic focus unit is very important. Based on detecting focus error , an automatic focusing unit has been given. It has ad- vantages of high focusing sensitivity of 0.1μm,wide range of 0. 5mm , dynamic frequency band of about 40Hz. The unit guarantees the high measurement resolution of the interferometer. Experimental re- sults show it is very effective. The research is valu- able to the development of the commercial instru- ments.