| 摘要 |
PROBLEM TO BE SOLVED: To provide a wide-range interferometric displacement measuring apparatus which does not use a high-stability laser, nor a laser whose wavelength can be varied with high accuracy. SOLUTION: When a distance from a body of an interferometer to an object 110 or displacement is interferometrically measured by using laser beams of a plurality of wavelengths, obtaining interference measurement values that are measured at respective wavelengths, and expanding a measurement range by a synthetic wavelength that is equivalently longer than the wavelengths of the laser beams from combinations of the respective wavelengths, the wavelengths of the plurality of laser beams are measured by using an optical comb 104. On this occasion, an interferometric measurement may be performed while the oscillation wavelength of a variable wavelength laser 101 is measured by using the optical comb, and feedback control is performed whereby laser beams of a plurality of predetermined wavelengths are obtained; a variable wavelength laser is caused to oscillate at an arbitrary wavelength to obtain interference measurement values at the plurality of wavelengths, and wavelengths (frequencies) of laser beams at timing when the respective interference measurement values are obtained are measured by the optical comb; or a plurality of lasers 416, 417 are used, and wavelengths of laser beams oscillated from the respective lasers are measured by the optical comb. COPYRIGHT: (C)2010,JPO&INPIT |
