Zeng Wenhan, Guo Jun, Jiang Xiangqian, Xie Tiebang, Li Zhu Huazhong University of Sci. & Tech., China
<正> A novel non-contact displacement sensor based on the focus detection principle and holographic diffractive grating principle is introduced for engineering surface measurement. This sensor adopts the diffractive grating as the independent measuring etalon. The focus needle is controlled by the servo-control system to track the topography changes and the defocusing is kept within the range of linearity. The diffractive grating follows the voice coil motor to record its displacement. The actual change of the surface topography is the sum of the defocusing and the displacement of the diffractive grating. The measurement range is±1mm and the resolution is 10nm. This sensor can realize fast, non-contact measurement of surface topography.
focus detection, planar diffractive grating, non-contact measurement
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