| 摘要 |
PROBLEM TO BE SOLVED: To provide a tracking-type laser interferometer for resuming measurement even if sight of a retro reflector is lost. SOLUTION: A pattern emission control unit 54 controls a changing mechanism 121 such that light from a light source is emitted along a predetermined pattern when determined by a first determining unit 521 that received-light amount of at least one of first and second light receiving means is not greater than a predetermined first threshold value. A tracking control unit 51 causes the changing mechanism 121 to keep track of a retro reflector 11 when determined by a second determining unit 522 that both of the received-light amounts of the first and second light reception units are greater than predetermined second threshold values during a time period in which the pattern emission control unit 54 controls the changing mechanism 121 for the emission of light from the light source along the predetermined pattern. The interferometer 1 emits light along the predetermined pattern to search for the retro reflector 11 upon losing sight thereof. Upon the detection of the retro reflector 11, the interferometer 1 keeps track of the reflector 11 again and resume measurement. COPYRIGHT: (C)2010,JPO&INPIT |
