Confocal laser displacement sensor using MEMS varifocal mirror

摘要

A confocal laser displacement sensor using a micro-machined varifocal mirror is reported. The focal length modulation is a key function for the sensor. The measurement speed and range depend on the mechanism. In this study, we propose to use the micro-machined varifocal mirror for the mechanism of the focal length modulation in the confocal displacement sensor. The electrostatically actuated varifocal mirror made by silicon was used. The working distance of the displacement sensor is designed to be 31 mm. The measurement range at 7 kHz is 310 μm. The linearity in the full scale range is from -1.5% to 0.85%.