| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive and highly accurate laser interference length measuring device for measuring a movement amount and a shape of an object to be measured, capable of removing the influence of wavelength fluctuation with time of a laser beam source for measuring length. SOLUTION: This interference length measuring device for measuring the movement amount and the shape of the object to be measured is provided with a length measuring interferometer which divides a beam from the laser beam source into a reference beam and a measuring beam, makes the two beams to interfere with each other and carries out a measurement of the object to be measured, and a correction interferometer having the same optical path length difference as that of the reference beam and the measuring beam. Then a measured value by the length measuring interferometer is corrected with a value measured by the correction interferometer. COPYRIGHT: (C)2003,JPO
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