Measurement of displacement and vibration by using the oblique ray method.

An optical system that can measure vibrations and displacements is developed by using the oblique ray method. By employing a single convex lens that plays both roles of sending and receiving the beams that are reflected by the target surface, the optical measurement system became compact and reliable. A position-sensitive detector is used to measure the position change of the beam spot on the target surface. The resolution of the optical system can be controlled by changing the optical magnitude of the objective lens and is designed to be less than 0.1 microm for the developed system.