Abstract: An optical interferometric range sensor includes a light source that emits light, interferometers that each generate interference light, a light receiver that receives the interference light to convert the interference light to an electric signal, and a processor that calculates a distance to a measurement target based on the electric signal resulting from the conversion. The light received by each of the optical couplers in the stages is split based on a first split ratio for a corresponding interferometer and a second split ratio for an optical coupler in a subsequent stage subsequent to a stage including the optical coupler receiving the light. The first split ratio and the second split ratio are set at least based on the first split ratio of the optical coupler receiving the light and a product of a first split ratio and a second split ratio of the optical coupler in the subsequent stage.

Abstract: 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.

Abstract: An optical interferometric range sensor includes a light source that emits light with a changing wavelength, an interferometer that receives the light emitted from the light source and generates interference light based on measurement light emitted from a sensor head to a measurement target and reflected from the measurement target and reference light traveling on an optical path at least partially different from an optical path of the measurement light, a light receiver that receives the interference light from the interferometer to convert the interference light to an electric signal, a processor that calculates a distance from the sensor head to the measurement target based on the electric signal resulting from conversion performed by the light receiver, an identifier that identifies the sensor head based on a beat signal generated by the interferometer, and a setter that sets a measurement condition corresponding to the sensor head identified by the identifier.

Abstract: An optical interference range sensor includes: a light source configured to project a light beam while continuously varying a wavelength thereof using a predetermined sweep frequency pattern; a processing unit configured to measure the distance to a measurement target based on an electrical signal converted by a light-receiving unit; and a storage unit configured to store distance information indicating the measured distance. The predetermined sweep frequency pattern includes a first sweep frequency pattern and a second sweep frequency pattern.

Abstract: A wavelength-swept light source projects a light beam. An interferometer includes a splitting unit that splits the light beam projected from the wavelength-swept light source into light beams radiated toward a plurality of spots on a measurement target. 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 that is at least partially different from an optical path of the measurement beam. A light-receiving unit receives the interference beams from the interferometer. A processor calculates distance to the measurement target by associating a detected peak of the interference beams with one of the spots. The optical path length difference between the measurement target and the reference beam is made different among the light beams split in correspondence with the plurality of spots.

Abstract: A light source projects a light beam while continuously varying a wavelength thereof. An interferometers generates an interference beam by interference between a measurement beam reflected at a measurement target as a result of a supplied light beam and a reference beam passing through an optical path that is at least partially different from an optical path of the measurement beam. A stages of optical couplers connected in series, each of the stages of optical couplers that receives the light beam from the light source, splits the received light beam into a beam proceeding to a corresponding interferometer and a beam proceeding to a downstream side, and supplies the split light beams. A suppressing unit suppresses a supply of a light beam from the downstream side to the upstream side. A processing unit calculates distance to the measurement target based on frequencies of an interference beams generated by the interferometers.

Abstract: 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.

Abstract: An optical interference range sensor includes a wavelength-swept light source, an optical coupler, an interferometer, a light-receiving unit, a processor, and a reflection point that reflects a light beam that is split and proceeds to a fourth port of the optical coupler, of a light beam projected from the wavelength-swept light source and input to a first port of the optical coupler. One or more of an optical path length, denoted by L1, from the third port of the optical coupler to the reference surface, an optical path length, denoted by L2, from the fourth port of the optical coupler to the reflection point, an optical path length, denoted by LH, from the reference surface to a leading end of a sensor head configured to radiate the measurement beam toward the measurement target, and a measurement range, denoted by R, for the measurement target may be set such that the expression L1?L2>(LH+R)*2 or L1?L2<LH*2 is satisfied.

Abstract: 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 D1 and D2 from 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 R1max of the measurement range of the first measurement head, optical path lengths S1 and S2 of 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 D1+R1max?S1<D2?S2 is satisfied.