There is provided an optical encoder with alignable relative positions between elements including an encoding medium, a sensor package and a memory. The sensor package includes a photodiode array and two alignment photodiodes opposite to the encoding medium. The memory records an alignment pattern associated with output signals of the two alignment photodiodes when the encoding medium and the sensor package are at nominal operating positions. When the encoding medium and the sensor package are not at the nominal operating positions, the relative position alignment is performed by adjusting current relative positions between the encoding medium and the sensor package to cause a current pattern associated with output signals of the two alignment photodiodes to be identical to the alignment pattern.

A method for positioning a magnetic device providing an impulse ring forming a coder and at least three magnetic detection cells forming a magnetic sensor. The impulse ring being provided with a target having pairs of magnetic poles. The number of pair of magnetic poles being counted. The magnetic detection cells are positioned around the target of the impulse ring according to the number of pair of magnetic poles and according to the number of detection cells.

A magnetic position measuring device includes a magnetic scale and a scanning unit movable relative thereto in at least one measuring direction. The magnetic scale has scale regions positioned at a regular pitch and have an oppositely oriented magnetization, the pitch indicating the extension of a scale region along the measuring direction. The scanning unit has at least one first detector unit cell, which includes three stripe-shaped magnetoresistive detector elements set apart from one another in the measuring direction, the longitudinal directions of the detector elements each having an orientation oriented perpendicular to the measuring direction. Adjacent detector elements along the measuring direction in the first detector unit cell have a distance of, for example, one twelfth of the pitch, relative to one another.

A sensor comprising: a first magnetoresistive (MR) bridge having a first stray field sensitivity; a second MR bridge having a second stray field sensitivity; and a driver circuitry configured to: (i) supply a first voltage to the first MR bridge, and (ii) supply a second voltage to the second MR bridge that is different from the first voltage, wherein supplying the first voltage and the second voltage to the first MR bridge and the second MR bridge, respectively, causes the first stray field sensitivity to match the second stray field sensitivity.

A rotor position detecting apparatus includes a rotor, a stator disposed in correspondence with the rotor and a sensing assembly disposed at one side of the rotor. The sensing assembly includes a substrate, a first magnetic element part and a second magnetic element part disposed on the substrate and a first ground pattern and a second ground pattern disposed on the substrate. The first ground pattern is electrically connected to the first magnetic element part. The second ground pattern is electrically connected to the second magnetic element part, and the first ground pattern is electrically disconnected from the second ground pattern.

An encoder includes scale and detection head. The detection head includes light source (transmitting unit) and light-receiving unit (receiving unit). The light-receiving unit includes light-receiving surface (receiving surface) and converts light received at the light-receiving surface 50 into differential detection signals with two phases and outputs the same. The light-receiving surface includes element array group including four element arrays provided in a parallel manner along an orthogonal direction, with each element array including a plurality of light-receiving elements (receiving elements). The plurality of element arrays in the element array group are disposed at positions where the sum of: (i) a distance in the orthogonal direction from a reference position to a positive phase signal element array; and (ii) a distance in the orthogonal direction from the reference position to the negative phase signal element array, is the same for all the phases of the at least two phases.

A scale includes a base material, an intermediate layer of soft magnetic material formed on one surface of the base material and roughened on face thereof opposite to the base material, and a scale pattern of a conductor formed on the intermediate layer.

A scale includes a base material, scale patterns arranged at a predetermined periodicity on a main surface of the base material, and a fluorine film that covers the scale patterns and is at least partly a monomolecular fluorine compound.

A feedback device for use in a gas turbine engine, and methods and systems for controlling a pitch for an aircraft-bladed rotor, are provided. The feedback device is composed of a circular disk and a plurality of position markers. The circular disk is coupled to rotate with a rotor of the gas turbine engine, to move along a longitudinal axis of the rotor, and has first and second opposing faces defining a root surface that extends between and circumscribes the first and second faces. The plurality of position markers extend radially from the root surface, are circumferentially spaced around the circular disk, and extending along the longitudinal axis from a first end portion to a second end portion. At least part of the first end portion and/or of the second end portion comprises a material having higher magnetic permeability than that of a remainder of the position markers.

A position sensing mechanism provided by the invention comprises an encoding element as a sensing signal source, a reading element for sensing signals of the signal source, and a processing unit for receiving and analyzing sensing signals output by the reading element, the position sensing mechanism has a main technical feature lying in a magneto-resistive unit in the reading element for sensing signals of the signal source being a tunneling magneto-resistor (TMR), and two layers of magnetic moments of a reference layer and a free layer of the tunneling magneto-resistor being perpendicular to each other, and in the reference layer and the free layer with the magnetic moments being perpendicular to each other, the magnetic moment of one of the layers is parallel to a film surface, and the magnetic moment of the other layer is perpendicular to the film surface.