DIFFUSE SURFACE INTERFERENCE POSITION SENSOR

摘要

Position of a diffusely scattering surface is detected by interfering backscattered light from respective input beams which illuminate a common spot. Through polarization of the input beams and appropriate filtering, backscattered light is isolated from specularly reflected light and interfered to form a fringe pattern on a detector. The position sensor has particular applicability as a push pin sensor in a hard disk servo system.