This invention provides a linear encoder having an arbitrary size while maintaining high producibility. An absolute linear encoder includes a long scale formed by continuously connecting a first short scale and a second short scale in which a first cyclic bit string and a second cyclic bit siring generated using the same initial value for different generator polynomials are arranged, and at least two sensors arranged at positions facing the long scale side by side in a longitudinal direction of the long scale.

The present disclosure provides a position detection device. The position detection device includes a movable unit, a light source unit and a color sensor. The movable unit can move along a moving direction and include one or more colored portions. The light source unit irradiates the colored portions with a light. The color sensor receives a reflected light reflected by the colored portions and detecting a color component.

The photoelectric encoder 1 includes a scale 2, and a detection head 3 including a light emitting unit 4, an index 5, and a detection unit 6. The index 5 includes a first index portion 50 consisting of diffraction portions and non-diffraction portions alternately juxtaposed at a predetermined pitch along the longitudinal direction of the scale 2, and a second index portion 51 consisting of diffraction portions and non-diffraction portions alternately juxtaposed at twice the pitch of the first index portion 50. The scale 2 is configured to include a first pattern portion 20 consisting of diffraction portions and non-diffraction portions alternately juxtaposed at a predetermined pitch along the longitudinal direction of the scale 2, and a second pattern portion 21 consisting of diffraction portions and non-diffraction portions arranged in a checkered pattern.

A method of applying a marking onto a metrological scale. The method includes locating one or more markings on the scale substrate in a provisional state; checking whether the one or more markings located on the scale substrate are acceptable; and finalizing the one or markings which are acceptable so as to transform the one or more markings into a finalized state.

An optical position-measuring device includes a scale and a scanning unit. The scale is connected to a first object, extends along a measurement direction and includes a first track having an incremental measuring graduation, and a second track having an absolute measuring graduation. The scanning unit is connected to a second object and includes a light source, a detector having an absolute detector arrangement configured to detect an aperiodic light pattern transmitted from the absolute measuring graduation onto a detection plane and an incremental detector arrangement configured to detect a periodic light pattern transmitted from the incremental measuring graduation onto a detection plane, and a fiber-optic plate arranged as a continuous component in front of the absolute detector arrangement and the incremental detector arrangement, wherein both absolute track information and incremental track information in the respective detection planes are transmitted via the fiber-optic plate in this manner.

An optical position-measuring device includes a scale and a scanning unit. The scale is connected to a first object, extends along a measurement direction and includes a first track having an incremental measuring graduation, and a second track having an absolute measuring graduation. The scanning unit is connected to a second object and includes a light source, a detector having an absolute detector arrangement configured to detect an aperiodic light pattern transmitted from the absolute measuring graduation onto a detection plane and an incremental detector arrangement configured to detect a periodic light pattern transmitted from the incremental measuring graduation onto a detection plane, and a fiber-optic plate arranged as a continuous component in front of the absolute detector arrangement and the incremental detector arrangement, wherein both absolute track information and incremental track information in the respective detection planes are transmitted via the fiber-optic plate in this manner.

This invention provides a linear encoder having an arbitrary size while maintaining high producibility.

An absolute linear encoder includes a long scale formed by continuously connecting a first short scale and a second short scale in which a first cyclic bit string and a second cyclic bit siring generated using the same initial value for different generator polynomials are arranged, and at least two sensors arranged at positions facing the long scale side by side in a longitudinal direction of the long scale.

A lens barrel that is capable of detecting an absolute position of a movable part with high accuracy. A first guide guides the movable part with an optical lens. A first sensor unit includes a first scale and first detection unit. The first scale in the movable part has a pattern that makes a signal output from the first detection unit monotonically increase. The first detection unit outputs the signal that continuously varies according to the movement. A second sensor unit includes a second scale in the movable part that has a periodic repeated pattern and a second detection unit that outputs a periodic signal by reading the second scale. A controller detects a position of the movable part based on the signals output from the first and second detection units. The first sensor unit is arranged nearer to the first guide in comparison with the second sensor unit.

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.

Methods and systems for the absolute high-resolution measurement of angle of rotation of a shaft, which allow for concurrent measuring of axial displacement and/or encoded identification information, are disclosed. Included is a method for measuring characteristics of a rotating shaft comprising obtaining optical signals by optically probing one or more patterns having a leading edge and a series of symbols disposed at one or more circumferences of the shaft; oversampling the optical signals; measuring time of arrival for the leading edges and determining therefrom an amount of time between arrival of two or more of the leading edges; interpolating and extrapolating the amount of time between arrival of the leading edges; and determining therefrom one or more of shaft twist, angle of rotation and/or axial loading, translation, or displacement. The methods include optically probing a pattern disposed around the circumference of a shaft that comprises a series of wedge-shaped symbols.