HIGH RESOLUTION OPTICAL INTERFEROMETER WITH PARALLEL MULTIPLE PASS CONFIGURATION AND APPARATUS FOR MEASURING DISTANCE USING THE SAME

摘要

PURPOSE: A multiple reflecting high resolution optical interferometer using a parallel back-reflection type optical element and a distance measuring apparatus using the same are provided to measure a long range of displacement by minimizing the limit of speed measurement with high resolution which is less than a nanometer. CONSTITUTION: An optical interferometer(100) comprises a first prism(110), a second prism(120), and a full reflecting mirror(130). The first prism and the second prism coat a surface with anti-reflective coating. The oblique sides of prisms are arranged to be faced in parallel. The first prism and the second prism arrange the vertex of an isosceles triangle to be crossed at a certain distance on a front view. The full reflecting mirror is placed in the lower part of the second prism and reflects a laser beam, which passes through the first prism, to the same route. The first prism and the full reflecting mirror are arranged on a linear translation stage and are operated by a measurement arm.