Theory Study of Nanometer Metrological Grating Based Two Times Moiré Fringe
To meet the demand of large displacement measurement instrument with nanometer precision, this paper introduces the metrological grating with the nanometer measurement precision and large displacement, based on two times' Moiré fringe principle. Its basic principle is that two indicated gratings are fixed on the same measuring base scale, when they move relatively to the scale grating, two groups of one time Moiré fringe will be produced, then two groups of lens are adopted to make the fringe move oppositely, at last the two times Moiré fringe will be produced through interference on the photoelectronic receive element. By subdivision of the two times Moiré fringe, this system can achieve 2.70×10-10m measurement resolution. In addition, this paper also analyse the optics system and light source.
Wei Gao, Yasuhiro Takaya, Yongsheng Gao and Michael Krystek
X.S. Ma et al., "Theory Study of Nanometer Metrological Grating Based Two Times Moiré Fringe", Key Engineering Materials, Vols. 381-382, pp. 501-504, 2008