Fiber-optic based scanning confocal microscopic interferometer for the measurement of surface topography in manufacturing process

A fiber-optic based scanning confocal microscopic interferometer in which digital feedback is used for precisely measuring the surface topography on a large-scale object of complex shape with steep surface slopes is developed. Analysis on interference formation is performed, showing the confocal characteristics of the proposed interferometer along its measurement path. The spatial resolution of the system is confirmed to be within 1 micrometer, and the measurement accuracy is better than 5 nanometers.