| 摘要 |
PROBLEM TO BE SOLVED: To provide a displacement gauge in which measurement errors due to wavefront aberrations do not occur. SOLUTION: A laser beam from a laser beam source 10, which emits low-coherence light, is divided into a laser beam L2 for reference and a laser beam L1 for measurement as parallel light by a beam splitter 15. By making the laser beam L2 for reference reflected at a first reflecting surface 17 and a second reflecting surface 18 of a reflector 16, the location of an optical axis A2 of the laser beam L2 for reference toward the beam splitter 15 after reflection at the reflector 16 is locationally displaced in parallel from an optical axis A1 of the laser beam L2 for reference divided by the beam splitter 15 toward a reference body to make the laser beam L2 for reference and the laser beam L1 for measurement to interfere with each other by the beam splitter 15. On the basis of the location of interference fringes 22 of their interference light L3, displacements of a body 14 to be measured are measured. COPYRIGHT: (C)2006,JPO&NCIPI
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