Patent ID: 11860037
Assignee: SHIMADZU CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An apparatus for determining a position of a movable mirror of an interferometer, the interferometer having a beam splitter, a fixed mirror, and the movable mirror, the apparatus comprising:
a) a laser light source;
b) a phase separation optical system configured to cause first light and second light to be separately detected, the first and second light being generated through the emission from the laser light source and the reflection by the fixed mirror and the movable mirror, respectively, the first and second light having different phases from each other;
c) a signal conversion unit configured to convert from the first light and the second light to generate to a first electrical sinusoidal wave signal and a second electrical sinusoidal wave signal, respectively;
d) a phase calculation unit configured to perform normalization and phase difference correction on each of the first sinusoidal wave signal and the second sinusoidal wave signal, and then calculate a phase of the first sinusoidal wave signal or the second sinusoidal wave signal in real time; and
e) a movable mirror position determination unit configured to determine a position of the movable mirror at a predetermined time point from a phase at the predetermined time point on a basis of a relationship between a position of the movable mirror and the phase.