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.

The present disclosure concerns a modulation unit for an encoder. The modulation unit is configured to be movably supported between a receiver for converting the detection of electromagnetic radiation into an output signal and an emitter for emitting electromagnetic radiation in the direction of the receiver, and comprises a code section comprising alternating opaque and transparent segments, the opaque segments being configured, in use, to interrupt emitted electromagnetic radiation between the emitter and receiver and the transparent segments being configured, in use, to permit emitted electromagnetic radiation to impinge on the receiver according to the position of the modulation unit. The modulation unit further comprises a plurality of index segments, wherein each index segment is uniquely identifiable in dependence on the output signal so as to serve as a starting point from which to begin monitoring the position of the unit.

An encoder apparatus comprising a scale comprising scale features in at least one track which define a series of incremental scale marks and at least one reference mark and a readhead comprising a light source, a diffraction grating, an incremental photodetector and a reference photodetector comprising at least two detector channels. The features defining the at least one reference mark are configured such that the at least one reference mark as resolvable by each of the at least two detector channels comprises a single feature. The optical arrangement of the encoder is such that a non-imaged representation of at least the track in which the at least one reference mark is contained falls onto the detector.

An encoder scale includes a tabular base material and an optical pattern provided above one surface of the base material, a first region and a second region being disposed side by side above the optical pattern. The first region includes a resin layer disposed above the base material and including photosensitive resin and a metal film disposed above the resin layer and formed of a metal material. The surface of the first region is configured mainly by a first surface having a normal line in the thickness direction of the base material. The surface of the second region is configured mainly by a second surface inclined with respect to the first surface.

The present invention is the optical fiber sensor, that laser pulses from a laser source are separated into a reference path and a measurement path by the second optical coupler via the first optical coupler, the first FRM is provided at an end of the reference path, the second FRM is provided at an end of the measurement path, and the reference reflected light of the first FRM and the measurement reflected light of the second FRM are interfered at the second optical coupler and are converted into three phases. The first phase pulses are transmitted to the optical synthesis section via the first optical coupler, second phase pulses are transmitted to the optical synthesis section via the first delay section, and third phase pulses are transmitted to the optical synthesis section via the second delay section. The time division pulse train is outputted from the optical synthesis section.

A device for detecting posture change of a operation part in a camera and a method for restoring posture are disclosed. The device may include a photo interrupter and a photoelectric baffle structure including a plurality of baffle pieces fixed on a base. The baffle pieces may include a first baffle piece and remaining second baffle pieces of a length specification different from that of the first baffle piece, and there is a gap between two adjacent baffle pieces. An output signal from the photo interrupter changes according to the aligning relationship between the photo interrupter and the baffle pieces. One of the photoelectric baffle structure and the photo interrupter may follow the motion of an operation part of the camera while the other one remains unmoved, so that a posture change of the operation part may be detected based on the output signal from the photo interrupter.

An optical element for generating diffraction orders for an encoder apparatus, in which the optical element includes an array of diffraction features arranged such that the spacing between the centres of adjacent diffraction features varies irregularly from one pair of adjacent features to the next.

An optical encoder includes an origin point detection scale having an origin point detection pattern and an inverse origin point detection pattern that is the inverse of the origin point detection pattern; a light source emitting light at the origin point detection scale; a light source grid that is inserted on the light source side of the origin point detection scale, the light source grid having two first light source grid patterns corresponding to the origin point detection pattern and the inverse origin point detection pattern, respectively; a photoreceiver detecting a signal from light that has passed through the origin point detection scale; and a photoreceiver grid inserted on the photoreceiver side of the origin point detection scale, the photoreceiver grid having two first photoreceiver grid patterns that are a pattern either identical to or the inverse of the first light source grid pattern.

An optical element for generating diffraction orders for an encoder apparatus, in which the optical element includes an array of diffraction features arranged such that the spacing between the centers of adjacent diffraction features varies irregularly from one pair of adjacent features to the next.

A rotational speed estimation method for an incremental encoder includes generating a plurality of pulse signals according to a plurality of square waves, detecting a time duration when the pulse signals reach a predetermined amount, and generating a rotational speed of a disc according to the predetermined amount, the time duration, and the total number of pulses corresponding to one rotation of the disc of the incremental encoder.