System for measuring the position of a mechanical member, which comprises an optical detection system and a positioning track arranged on two mechanical members of a mechanical device. The positioning track is provided with a succession of multiple sectors, each of which comprises a first delimitation section and a second delimitation section spaced from each other, and a first identification section and a second identification section which are provided with a different optical contrast with respect to the first delimitation section and to the second delimitation section. In each sector, the first identification section is delimited between the first delimitation section and the second delimitation section. In addition, the length of the identification sections of each sector is different from the length of the identification sections of each other sector of the succession, so as to unequivocally identify the corresponding sector.

Provided is an encoder apparatus including: a scale provided to a rotation shaft of a drive apparatus and having a predetermined pattern; a detector that detects the predetermined pattern; a rotation information calculator that calculates rotation information on the rotation shaft by using detection results of the detector; an eccentricity information calculator; and a corrector that corrects the rotation information.

A vehicle seat includes a seat bottom and a seat back. The seat back is coupled to the seat bottom and arranged to extend in an upward direction away from the seat bottom. The vehicle seat further includes an electronics system.

An absolute encoder includes: a scale on which plural marks are arrayed; plural detecting devices each configured to detect a mark group of the plural marks and output a signal corresponding to the mark group; and a processor configured to obtain a coordinate of the scale based on outputs of the detecting devices. The plural marks are arrayed such that a signal obtained by adding plural signals respectively output from the detecting devices includes a periodic signal corresponding to plural periods. The processor obtains first position data based on a magnitude of at least one signal of the plural signals, obtains second position data having a resolution higher than that of the first position data based on a phase of the periodic signal, and generates data representing the coordinate based on the first and second position data.

An optical position-measuring device for absolute position determination includes a material measure extending along a measurement direction and including an incremental graduation and an absolute code. A scanning unit movable relative to the material measure has a light source, a scanning grating for optically scanning the incremental graduation and a detector device. The detector device includes an incremental detector for generating incremental signals from the optical scanning of the incremental graduation and an absolute detector for generating absolute signals from optical scanning of the absolute code. A common detection plane is located at a defined perpendicular distance from the scanning grating and/or a periodicity of a fringe pattern on the incremental detector is selected such that, in the event of scattering contamination in a region of the material measure and/or the scanning grating, amplitudes of the incremental signals and the absolute signals drop off equally.

A rotation detecting unit includes a light emitting device, a light receiving device, an output device, a rotatable plate, and a discriminating device. The rotatable plate includes a first portion and a second portion which are alternately provided along a circumferential direction, a third portion provided between the first portion and the second portion, and a fourth portion provided between the second portion and the first portion. When a region of the first portion is irradiated with light emitted from the light emitting device and received by the light receiving device, received light quantity of the light receiving device is a maximum. When a region of the second portion is irradiated with the light, the received light quantity is a minimum. When the third or fourth portion is irradiated with the light, the received light quantity is larger than the minimum and is smaller than the maximum.

A vehicle seat includes a seat bottom and a seat back. The seat back is coupled to the seat bottom and arranged to extend in an upward direction away from the seat bottom. The vehicle seat further includes an electronics system.

A rotation detecting unit includes a light emitting device, a light receiving device, an output device, a rotatable plate, and a discriminating device. The rotatable plate includes a first portion and a second portion which are alternately provided along a circumferential direction, a third portion provided between the first portion and the second portion, and a fourth portion provided between the second portion and the first portion. When a region of the first portion is irradiated with light emitted from the light emitting device and received by the light receiving device, received light quantity of the light receiving device is a maximum. When a region of the second portion is irradiated with the light, the received light quantity is a minimum. When the third or fourth portion is irradiated with the light, the received light quantity is larger than the minimum and is smaller than the maximum.

An optical position-measuring device for absolute position determination includes a material measure extending along a measurement direction and including an incremental graduation and an absolute code. A scanning unit movable relative to the material measure has a light source, a scanning grating for optically scanning the incremental graduation and a detector device. The detector device includes an incremental detector for generating incremental signals from the optical scanning of the incremental graduation and an absolute detector for generating absolute signals from optical scanning of the absolute code. A common detection plane is located at a defined perpendicular distance from the scanning grating and/or a periodicity of a fringe pattern on the incremental detector is selected such that, in the event of scattering contamination in a region of the material measure and/or the scanning grating, amplitudes of the incremental signals and the absolute signals drop off equally.

A rotary scale apparatus for an encoder apparatus including a planar disc on which at least one track including scale features is provided, in which the planar disc includes a hole through its centre for receiving a cylindrical shaft, and in which the rotary scale member includes at least three cantilevered spring members which are provided substantially in plane with the planar disc and spaced around the edge of the hole, for engaging with, and radially locating the disc on, a cylindrical shaft inserted therethrough.