Omron Corporation

Yusuke Nagasaki

Masayuki Hayakawa

Kazuya Kimura

Hisayasu Morino

Jun Takashima

Seishiro Kojima

A light source projects a light beam. An interferometer includes a splitting unit that splits the light beam. The interferometer generates interference beams with the respective split light beams. Each of the interference beam is generated by interference between a measurement beam radiated toward the measurement target and reflected at the measurement beam and a reference beam passing through an optical path. A light-receiving unit receives the interference beams. A processor calculates a distance to the measurement target by associating at least one detected peak with at least one of the spots in accordance with a mirror surface mode or a rough surface mode. The optical path length difference is made different among the split light beams. In the mirror surface mode, the processor uses a distance calculated based on a peak corresponding to a spot for which the optical path length difference is shortest.

Optical interference range sensor

In one or more embodiments of an optical interference measurement apparatus, first return light received by a first measurement head is guided to a detector via a first optical path and a fiber coupler. Second return light received by a second measurement head is guided to the detector via a second optical path and the fiber coupler. Optical path lengths Dand Dfrom the fiber coupler to a leading end of the first measurement head and a leading end of the second measurement head respectively, a maximum optical path length Rmax of the measurement range of the first measurement head, optical path lengths Sand Sof the first reference light that interferes with the first return light and of the second reference light that interferes with the second return light respectively are set such that the relation D+Rmax−S<D−Sis satisfied.

Optical interference measurement apparatus having optical path lengths set to satisfy a given relation

A conversion unit converts a first electrical signal to a first distance value indicating a distance from an interferometer to a measurement target. An inclination value calculation unit calculates an inclination value based on the first distance value. A first distance value correction unit corrects the first distance value based on the inclination value. A second distance value correction unit calculates a second distance value indicating a distance from the optical interference range sensor to the measurement target based on the first distance value that has been corrected by the first distance value correction unit. If the number of times that the first electrical signal is detected is smaller than a second threshold, the first distance value correction unit corrects the first distance value based on an inclination value that precedes the inclination value associated with the first distance value in a storage unit.

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Kyoto, Japan

Yusuke Nagasaki