| 摘要 |
PROBLEM TO BE SOLVED: To realize a multi-beams laser interferometer small in size with high degree of freedom. SOLUTION: The multi-beams laser interferometer is composed of a plurality of laser beams, a layer-built optical element 40 which forms surfaces of polarized beam splitter 48, 49, a surface of beam splitter 42, reflective surfaces 43-47, or their combined surfaces and is disposed at an arbitrary section of arbitrary laminating layers of a laminating plate that is formed by laminating a plurality of parallel transparent plates and worked so that an incident/emitting surface for the laser beams is oblique to the laminating layers, a laser interference unit which divides the plural laser beams into probe beams and reference beams respectively, composites the reference beams reflected back by reference reflectors 54, 56 and the probe beams reflected back by measurement reflectors 58, 60 mounted on an object, and generates a plurality of interference beams 61, 62, and a detector which detects change of each interference fringes of the plural interference beams. The layer-built optical element is composed of a transparent plate 50 joined on the incident/emitting surface for the laser beams.
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