Mitutoyo Corporation

Naoyuki Taketomi

Makoto Abbe

Shinichi Hara

Shinichirou Yanaka

Makoto Abe

Yasushi Ueshima

Sinichirou Yanaka

When measurement is conducted using a measurement system utilizing a tracking-type laser interferometer, laser light is emitted at a retroreflector, the tracking-type laser interferometer is placed in a tracking state, and a displacement body is displaced to a desired point and a combination of position data of the displacement body at a single desired location and rotation position data of a biaxial rotation mechanism from the tracking-type laser interferometer is stored. When a received light determiner determines that there is an abnormality in an amount of light, the positions of the displacement body and the biaxial rotation mechanism are maintained, and the displacement body and biaxial rotation mechanism are displaced to the respective stored, predetermined positions. When the abnormality in the amount of received light is eliminated after displacement, the tracking-type laser interferometer is placed in the tracking state and measurement is restarted.

Measurement system using tracking-type laser interferometer and return method of the measurement system

A tracking type laser interferometer that detects displacement of a retroreflectorbeing an object to be measured by utilizing interference of a laser beamirradiated onto the retroreflectorand reflected by the retroreflectorin the returning direction, and carries out tracking by means of a two-axis turning mechanismusing displacement in the position of the optical axis of the laser beam; the same tracking type laser interferometer, includes; a light irradiatorthat emits a fan-shaped laser lightthat is fan-shaped including the optical axis of the laser beam, is interlocked with turning movements of the two-axis turning mechanismaround an axis orthogonal to the center axis of the corresponding fan shape; and a light receptorthat has a specific positional relationship with the retroreflectoror the light irradiatorand receives the fan-shaped laser light. Thereby, tracking can be automatically reset when the tracking is disabled due to a reason such as interruption of laser light or initial adjustment work can be automated when commencing measurement.

Tracking type laser interferometer and method for resetting the same

An optical axis polarization type laser interferometer including a reference sphere which forms a reference of measurement, a retro-reflecting means disposed at a measurement object, a laser interference measuring apparatus for outputting a measurement value corresponding to an increase or a decrease in the distance to and from the retro-reflecting means; and a two-axis turning mechanism for turning an emission beam of the corresponding laser interference measuring apparatus centering around the reference sphere, which measures, with the center coordinates of the reference sphere used as the reference, the distance to and from the retro-reflecting means where the optical axes of the emission beam from the laser interference measuring apparatus mounted on the two-axis turning mechanism and a return beam become parallel to each other, wherein the fixing portion of the first axis turning mechanism installed at the base part of the apparatus is disposed at the inner circumference thereof, the reference sphere is placed at the fixing portion thereof, and at the same time, the moving portion of the first axis turning mechanism is placed at the outer circumference of the fixing portion, and the second axis turning mechanism is mounted on the moving portion thereof. Therefore, complexities in mechanism design can be simplified to a large extent with respect to the first axis turning mechanism that composes the two-axis turning mechanism.

Optical axis polarization type laser interferometer

A method for estimating an absolute distance between a tracking laser interferometer and a retroreflector is provided. The tracking laser interferometer includes the retroreflector for reflecting and returning an incident measurement light in an incident direction and a two-axis rotating mechanism for rotationally moving in an exit direction of the measurement light so that optical axes of the measurement light and return light are collimated.

Method for estimating absolute distance of tracking laser interferometer and tracking laser interferometer

An optical-axis deflection type laser interferometer includes a reference ball serving as a measurement reference, a retroreflecting means disposed at an object to be measured, a laser interferometer length measuring apparatus outputting a measurement value between the apparatus and the retroreflecting means, and a rotational mechanism that rotates a beam projected from the laser interferometer length measuring apparatus around the reference ball. The laser interferometer additionally includes a displacement gauge that measures an error caused by a relative motion between the reference ball and the laser interferometer length measuring apparatus, and a rectilinear movement mechanism that displaces these in a direction of an optical axis of a measurement beam with respect to the reference ball while maintaining a relative positional relationship between the laser interferometer length measuring apparatus and the displacement gauge. With this structure, calibrating the displacement gauge without preparing a special calibrating device becomes possible, thereby securing traceability thereby securing traceability.

Optical-axis deflection type laser interferometer, calibration method thereof, correcting method thereof, and measuring method thereof

A laser tracking interferometer directs a laser beam to a retroreflector serving as an object to be measured to sense a displacement of the retroreflector using interference with a laser beam back reflected from the retroreflector. The laser tracking interferometer includes: a reference sphere; a carriage that rotates about a center of the reference sphere; a laser interferometer; a displacement gage for providing a displacement signal corresponding to a relative displacement between the reference sphere and the displacement gage; a data processing apparatus for computing a displacement of the retroreflector; a position sensitive detector for providing a position signal corresponding to deviation of a laser beam; and a controller for controlling rotation of the carriage based on the position signal so that the amount of deviation becomes zero.

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Tsukuba, Japan

Naoyuki Taketomi