Various embodiments relate to devices for measuring the state of devices and multi-stage rotary encoders as well as to associated sensors. In order to simplify the design of devices which can be read out electronically and multi-turn rotary encoders, according to some embodiments a device having at least one rotatable wheel, at least one light source and at least one polarization sensor is proposed, the wheel being at least partially transparent and polarization-maintaining, parts of the wheel being configured as pole filters, it being possible for light which exits the light source to be polarized by the pole filter and to be received by the polarization sensor.

An encoder includes an optical scale that has a phase difference plate, a light source section that irradiates the phase difference plate with light, and a light receiving section that receives the light from the phase difference plate, and outputs a signal corresponding to a received light intensity. The light emitted from the light source section is linearly polarized, and the light receiving section outputs a signal corresponding to a polarization state of the light from the phase difference plate.

An encoder includes a layered structure including a metal plate, a dielectric layer arranged on the metal plate, and a plurality of metallic components arranged on the dielectric layer to form a pattern of resonant circuits. The encoder includes an emitter to emit a waveform of a resonant frequency to the layered structure and a receiver to measure amplitudes of the waveform reflected from the layered structure. The processor operatively connected to a memory storing data relating positions of the emitter with amplitudes of the reflected waveform determines a position of the emitter from the measurements of the amplitudes based on the data. The encoder includes an output interface to render the position of the emitter.

An encoder includes a layered structure including a metal plate, a dielectric layer arranged on the metal plate, and a plurality of metallic components arranged on the dielectric layer to form a pattern of resonant circuits. The encoder includes an emitter to emit a waveform of a resonant frequency to the layered structure and a receiver to measure amplitudes of the waveform reflected from the layered structure. The processor operatively connected to a memory storing data relating positions of the emitter with amplitudes of the reflected waveform determines a position of the emitter from the measurements of the amplitudes based on the data. The encoder includes an output interface to render the position of the emitter.

A sensor including: a generating unit; a detecting unit that detects the object to be detected generated by the generating unit; and a substrate at which the generating unit and the detecting unit are provided. The substrate is a flexible substrate that includes a first portion provided with the generating unit and a second portion provided with the detecting unit, the first portion and the second portion being integrated, and that takes a curved shape or a bent shape in which a surface of the first portion at which the generating unit is provided and a surface of the second portion at which the detecting unit is provided face each other. A plate support member is attached to a back-side surface of at least one of the surface of the first portion and the surface of the second portion.

A sensor configured to detect displacement of a rotation angle of a shaft due to a rotation or a turn of the shaft, the sensor includes: a bearing rotatably supporting the shaft; and a housing including a bearing hole to which the bearing is fixed. The shaft and an inner circumferential surface of the bearing are fixed to each other by an adhesive agent, and an outer circumferential surface of the bearing and an inner circumferential surface of the bearing hole of the housing are fixed to each other by an adhesive agent.

An encoder includes a light emitting portion emitting light, an optical element portion splitting the light into a first beam and a second beam, an optical scale receiving the first beam and the second beam from the optical element portion, and a light receiving portion receiving the first beam and the second beam from the optical scale and outputting a signal in accordance with intensity of the received light, in which the optical element portion includes a prism on which the light is incident, a beam splitter disposed on the prism and splitting the light incident on the prism into the first beam heading for the optical scale and the second beam heading for an inside of the prism, and a first mirror portion disposed on the prism and reflecting the second beam from the beam splitter toward the optical scale.

A rotation detection apparatus, including: a beam source for emitting a beam of polarized light; a decohering arrangement for eliminating or reducing the degree of coherence between first and second independent polarization components of the polarized light to produce a decohered beam of polarized light; a detector for outputting a signal in dependence on the intensity of light incident thereupon, the detector arranged so that the decohered beam of polarized light is incident upon it; a polarizer for location in the path of the decohered beam of polarized light such that rotation of the polarizer relative to the decohered beam of polarized light results in a variation of the intensity of light incident upon the detector from the beam source and a corresponding variation in the signal output from the detector; and a processor for detecting the relative rotation based on the variation of the signal output from the detector.

An encoder includes an optical scale that is so provided as to be pivotable around a pivotal axis and includes a polarizing portion having a polarization characteristic, a light outputting portion that outputs linearly polarized light toward the polarizing portion, and a light detecting portion that detects the linearly polarized light from the optical scale. The light outputting portion includes a vertical cavity surface emitting laser, and light emitted from the vertical cavity surface emitting laser spreads at an angle greater than or equal to 5 but smaller than or equal to 20.

An optical encoder unit includes: a light source having a predetermined light distribution; an optical scale having a polarizer whose polarization direction on a plane is along a predetermined direction, and whose polarization direction is changed according to rotation; and an optical sensor unit including a first photoreceiver, a second photoreceiver, a third photoreceiver, and a fourth photoreceiver for receiving incident light that is light source light from the light source made incident on the respective photoreceivers by passing through or being reflected by the optical scale. An emitting surface of the light source and the optical sensor unit are arranged at positions so as to receive a light intensity that is predetermined times greater or more than that corresponding to dark current of the optical sensor.