公开(公告)号：US10120059B2

公开(公告)日：2018-11-06

申请号：US15664051

申请日：2017-07-31

申请人： MITUTOYO CORPORATION

发明人： Shinichi Hara

IPC分类号： G01S17/66 ,  G01S3/786

摘要： A laser interferometer that includes a laser interferometer, an position sensitive detector detecting an offset of an optical axis of the laser interferometer, a biaxial rotator turning the laser interferometer toward an arbitrary direction, an angle sensor detecting a rotation angle of the biaxial rotator, a retro reflector reflecting reflected light in a direction parallel to incident light, and a controller performing feedback control of the biaxial rotator so as to track the retro reflector based on signals from the position sensitive detector and the angle sensor. The tracking-type laser interferometer starts tracking control when return light from the retro reflector is returned to a detection range of the position sensitive detector, and changes gain for the feedback control in accordance with a behavior for a position of the return light on the position sensitive detector due to the tracking control.

公开(公告)号：US11635518B2

公开(公告)日：2023-04-25

申请号：US16887941

申请日：2020-05-29

申请人： Mitutoyo Corporation

发明人： Hiroki Ujihara ,  Yoshimasa Suzuki ,  Shinichi Hara

IPC分类号： G01S17/34 ,  G01S7/481 ,  G01S7/48 ,  G01B9/02003

摘要： A measurement apparatus, including: a laser apparatus that outputs a frequency-modulated laser beam with a plurality of modes; a branching part that branches the frequency-modulated laser beam into a reference light and a measurement light; a beat signal generation part that generates a plurality of beat signals by mixing the reference light and a reflected light that is reflected by radiating the measurement light onto an object to be measured; a conversion part that converts the plurality of beat signals into digital signals by sampling the beat signals at a frequency greater than or equal to four times a resonator frequency of the laser resonator; and a calculation part that calculates a distance from the measurement apparatus to the object to be measured on the basis of the digital signals is provided.

公开(公告)号：US20210011155A1

公开(公告)日：2021-01-14

申请号：US16921839

申请日：2020-07-06

申请人： Mitutoyo Corporation

发明人： Yoshimasa Suzuki ,  Shinichi Hara ,  Shinji Komatsuzaki ,  Ryusuke Kato ,  Hiroki Ujihara ,  Masayuki Nara ,  Tomotaka Takahashi

IPC分类号： G01S17/08 ,  G01S7/48 ,  G01S7/481

摘要： A measurement apparatus includes a laser apparatus, a branching part that branches a frequency-modulated laser beam output by the laser apparatus into a reference light and a measurement light; a beat signal generation part that generates a beat signal by mixing a reflected light and the reference light, a conversion part that converts the beat signal into a digital signal at a first sampling rate and frequency-analyses it, an extraction part that extracts a signal component corresponding to a cavity frequency from the frequency-modulated laser beam, a digital filter that digitally filters the extracted signal component at a second sampling rate; and a calculation part that calculates a difference in a propagation distance between the reference light and the measurement light.