LASER LENGTH MEASURING INSTRUMENT

Japanese Patent JPH0278903

A

PURPOSE:To reduce the influence of linear expansion by installing a composite interferometer composed of two interferometers on a moving table to be measured, and arranging two fixed corner cubes and the composite interferometer on the same straight line. CONSTITUTION:This laser length measuring instrument is equipped with the composite interferometer 14 composed of two 1st and 2nd interferometers which are installed on the moving table to be measured and consists of polarization beam splitters 4 and 7 and corner cubes 9 and 13, the 1st and 2nd corner cubes 9 and 13 which are fixed on the moving table to be measured symmetrically about said interferometer 14 at nearly the same distance and almost on the same straight line, and an optical system of optical path constitution wherein laser light beams to two frequencies are propagated to the 1st and 2nd corner cubes 9 and 13 independently. The composite interferometer 14 and the 1st and 2nd corner cubes 5 and 8 are arranged on the same bench 8 and the linear expansion of the bench 18 due to temperature variation appears to the same extent between the cube 5 and interferometer 14, and the cube 8 and interferometer 14, so the expansion due to the linear expansion is canceled. Further, the cubes 5 and 8 are installed at a distance, so the alignment of the optical system is facilitated.

NAKAJIMA KOJI
SHIMADA KATSUHIKO
OGAWA KUNIHIKO

JP23056888A

March 19, 1990

September 14, 1988

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YASKAWA DENKI SEISAKUSHO KK

G01B9/02; G01S17/32; (IPC1-7): G01B9/02; G01S17/32

Masashi Kobori (2 outside)

Next Patent: JPH0278904