Interferometry for Online/In-Process Surface Inspection

Interferometers are normally operated in environment-controlled optical laboratories because vibrations will induce errors in measurement results. In order to extend the application of interferometry to shop floor inspection, two methods are adapted: one method is to introduce a reference interferometer and vibration compensation system to the main interferometer, to compensate for the environmental disturbance; and the other method is to realize the data sample in just one image shot. Each method has its own applications. With the advances of these technologies, the use of interferometry as a highly accurate and fast measurement method will become more common in shop floor measurements and inspections.

Keywords: online/in-process measurement, surface measurement, environmental disturbance, vibration compensation, reference interferometer, common path