A rotation angle encoder apparatus is disclosed. The rotation angle encoder apparatus may comprise a plurality of light sources, a plurality of light detectors, and a plurality of pinions rotatable about a shaft. Each of the pinions may comprises a plurality of teeth and a plurality of gaps. The rotation angle encoder apparatus may comprise a plurality of stacked configurations such that, when the shaft is rotated, transmissivity may be measured to determine or calculate at least one measurement, such as an angle of rotation, position, movement, distance, or other discernable measurement. The rotation angle encoder apparatus with a plurality pinions and associated measurable transmissivities may enable an optical spectrum analyzer to increase wavelength accuracy and improve resolution in optical measurements.

A photointerrupter includes a light emitter and a light receiver integrally formed with each other. The light emitter includes at least two light sources and emits light. At least one of the at least two light sources are individually tunable in light intensity. The light receiver receives the light from the light emitter.

The subject disclosure relates to techniques for determining a positioning error of a rotary encoder. A process of the disclosed technology can include steps of receiving measurement data including an angle and timestamp measured at each of a plurality of positions during a rotation of a rotary encoder, determining an angular velocity, at each of the plurality of positions, based on the corresponding measurement data, and determining a positioning error of the rotary encoder based on the angular velocity at each of the plurality of positions. Systems and machine-readable media are also provided.

An encoder includes a disc and a sensor. The disc has a circular surface with a central axis and is rotatable around the central axis. The disc has a slit row provided on the circular surface. The slit row includes slits arranged in a circumferential direction of the circular surface around the central axis and in a radial direction of the circular surface. The sensor is provided opposite to the slit row on circular surface. The sensor has a first light receiver and a second light receiver. The first light receiver is configured to output a first light receiving signal as the slit row rotates along the circumferential direction when the disc rotates around the central axis. The second light receiver is configured to output a second light receiving signal as the slit row moves along the radial direction when the disc rotates around the central axis.

An electronic device is described. The electronic device may include a housing, a rotatable crown, and a self-mixing interferometry (SMI) sensor positioned within the housing. The rotatable crown may include an array of retroreflective surface features that reflect incident light back to a light source. Each retroreflective surface feature of the array of retroreflective surface features may be formed as a corner-cube with three perpendicular faces. The SMI sensor or associated processing electronics may compare originally emitted light with reflected light to identify a movement or distance of the rotatable crown with respect to the SMI sensor.

Embodiments of the present disclosure provide an optical encoder that has magnetic elements embedded in a shaft or shaft of the optical encoder. Further, the optical encoder is hermitically sealed and is configured to rotate based on a magnetic field between the optical encoder and an actuation member.

The photoelectric rotary encoder includes: a generally disk-shaped scale with a grating-like pattern formed with a predetermined period along a measurement direction, the measurement direction being a direction of rotation of a measurement target that rotates on a predetermined axis, the scale being plate-like and centered on an axis of rotation; and a head that detect, from the scale, the amount of displacement caused by the rotation of the measurement target. The head includes a light source, a diffraction unit with grating parts, and a light-receiving unit with light-receiving elements. The grating parts of the diffraction unit are formed as deformed grating parts that spread cut wide, from the center on the axis of rotation, along the grating-like pattern of the scale. The light-receiving elements are formed as linear grating parts.

A rotary encoder includes a rotating shaft, first and second encoder wheels, first and second detectors and a processor. The first encoder wheel includes coaxially disposed first and second portions. The first portion has first graduation features. The second portion has a first positioning structure. The second encoder wheel includes coaxially disposed third and fourth portions. The third portion has second graduation features. The fourth portion has a second positioning structure meshing with the first positioning structure, so that the first graduation features and the second graduation features are staggered, and the first encoder wheel and the second encoder wheel are coaxially mounted on the rotating shaft. The first and second detectors detect the first and second graduation features and output first and second signals, respectively. The processor calculates a rotating angle of the rotating shaft according to the first and second signals.

An information processing apparatus includes an acquisition unit configured to acquire a first phase signal and a second phase signal that are acquired by measuring a rotation of a moving object, and a calculation unit configured to calculate a rotational angle by an iterative calculation so as to satisfy a relational expression bearing an arctangent. The relational expression bearing the arctangent uses a first cosine wave and a second cosine wave at a higher harmonic of the first cosine wave for the first phase signal, and a first sine wave and a second sine wave at a higher harmonic of the first sine wave for the second phase signal. The first phase signal and the second phase signal may, for example, be analog signals having a wave shape.

A rotary encoder system for registering the rotary angle position and/or angular speed of a rotary shaft which extends along an axis of rotation, including at least two optical marks at the rotary shaft, an optical sensor with a pixel matrix having pixel points, an imaging device for imaging each mark in a substantially axial direction on the pixel matrix as a mark image, and an evaluation device for reading and evaluating the pixel matrix in order to determine data in relation to the rotary angle position and/or angular speed. Further, the marks, the imaging device and pixel points are embodied in such a way that the mark images on the pixel matrix have at least the area of a pixel point, and the evaluation device is embodied to establish the location of the centroids of the mark images on the pixel matrix.