Abstract: An absolute encoder includes: a scale including an optical pattern that includes code patterns for a plurality of cycles; an illumination unit that outputs light for illuminating the scale; a light detection unit that detects light from the scale; a section determination unit that determines, for a region of the optical pattern divided into a plurality of sections, the section to which a code string belongs; and an absolute position calculation unit that obtains an absolute position of the scale on the basis of the section determined and the code string. When N is the number of the cycles of the code patterns on the scale, in a case where N is equal to two, the number of the sections is three or more, and in a case where N is equal to three or more, the number of the sections is N or more.

Abstract: A rotation speed detector includes: a base material to be attached to a rotating body; a first magnetic pole having an arcuate strip shape and provided on the base material; a second magnetic pole having an arcuate strip shape and provided on the base material; and a power generation element including a magnetic wire configured to cause a large Barkhausen effect, and a pickup coil. The power generation element is arranged to face the first magnetic pole and the second magnetic pole so that a longitudinal direction of the magnetic wire is provided along a radial direction of the first magnetic pole and the second magnetic pole. A non-magnetic gap is provided between the first magnetic pole and the second magnetic pole.

Abstract: A rotation speed detector includes: a base material to be attached to a rotating body; a first magnetic pole having an arcuate strip shape and provided on the base material; a second magnetic pole having an arcuate strip shape and provided on the base material; and a power generation element including a magnetic wire configured to cause a large Barkhausen effect, and a pickup coil. The power generation element is arranged to face the first magnetic pole and the second magnetic pole so that a longitudinal direction of the magnetic wire is provided along a radial direction of the first magnetic pole and the second magnetic pole. A non-magnetic gap is provided between the first magnetic pole and the second magnetic pole.

Abstract: A power generation element includes a magnetic member that produces a large Barkhausen effect and magnetism collection members including an insertion part having the magnetic member inserted therethrough. The magnetism collection member includes a first component on an opposite side of a boundary plane to a magnetic field generation unit and a second component on the same side of the boundary plane as the magnetic field generation unit, the boundary plane passing through a center of an imaginary circle inscribed in the insertion part and having a diameter equal to a length of the insertion part in a third direction perpendicular to first and second directions, the first direction is a direction of the insertion of the magnetic member, and the second direction is a direction in which the magnetic field generation unit is disposed. A volume of the second component is larger than a volume of the first component.

Abstract: A power generation element includes a magnetic member that produces a large Barkhausen effect and magnetism collection members including an insertion part having the magnetic member inserted therethrough. The magnetism collection member includes a first component on an opposite side of a boundary plane to a magnetic field generation unit and a second component on the same side of the boundary plane as the magnetic field generation unit, the boundary plane passing through a center of an imaginary circle inscribed in the insertion part and having a diameter equal to a length of the insertion part in a third direction perpendicular to first and second directions, the first direction is a direction of the insertion of the magnetic member, and the second direction is a direction in which the magnetic field generation unit is disposed. A volume of the second component is larger than a volume of the first component.