Patent ID: 9684158
Date: 2017-06-20
CPC Classifications: G01B,G02B

Claim:
1. A reference interferometer comprising: a second object lens magnifying an image of a target object into a first image; a camera capturing the first image; a beam splitter directing a portion of a first light irradiated from a light source or a portion of a second light emitted from the second object lens to the camera and to one of a plurality of reference mirrors by penetrating or reflecting; a first object lens focusing a third light emitted from the beam splitter on the one of the plurality of reference mirrors, wherein the plurality of reference mirrors reflect the third light incident from the first object lens; a plurality of reference mirror brackets supporting the plurality of reference mirrors, respectively, wherein each of the plurality of reference mirror brackets is disposed at a rotary plate and has a substantially same central angle with respect to a center of the rotary plate; a motor generating a rotational force to the rotary plate; an initial rotation angle sensor sensing an initial rotation angle of the rotary plate; and a control device rotating the rotary plate by controlling the motor in response to a command of a user, sensing an initial rotation angle using the initial rotation angle sensor, and controlling a rotation of the rotary plate to select at least one of the plurality of reference mirrors.