An optical encoder comprises an emitter; a receiver; a reflector; and a code carrier, wherein the emitter emits electromagnetic radiation along an emission axis in the direction of the reflector and the reflector deflects the electromagnetic radiation along a reception axis in the direction of the receiver. The code carrier is movably supported and has a sequence of code sections to interrupt or to give way for the emitted electromagnetic radiation to impinge on the detector in dependence on the position of the code carrier, wherein the emission axis and the reception axis extend at an alignment angle with respect to one another that has a value in the range from 30 degrees to 150 degrees.

A shadow-cast encoder apparatus includes a scale and a readhead. The readhead includes at least one electromagnetic radiation source for illuminating the scale in order to produce a shadow-cast fringe pattern at a detector configured to detect the shadow-cast fringe pattern. The encoder apparatus can be configured so as to suppress the total harmonic distortion of the fringe pattern, e.g. such that the total harmonic distortion of the fringe pattern is not more than 6%.

An optical position-measurement device includes a reflection measuring standard and a scanning unit, which is movable in relation thereto in at least one measurement direction. The reflection measuring standard has an incremental measuring graduation and a reference marking in at least one reference position. In addition to scanning device(s) for the incremental signal generation, the scanning unit includes for the reference signal generation at least one light source, imaging optics, a diaphragm structure arranged in a diaphragm plane, and a plurality of detector elements. Via the imaging optics, imaging of the reference marking onto the diaphragm structure is implemented. The reference marking is provided on the reflection measuring standard and is integrated into the incremental measuring graduation. In addition, the imaging optics has a variable, object-side focal length along a transversal direction oriented perpendicular to the measurement direction.

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 encoder unit includes a magnetic encoder having a main gear fixed to a rotation shaft, a plurality of auxiliary gears meshing with the main gear, magnets placed in the respective auxiliary gears, and a plurality of magnetic sensors on which magnetic fields of the corresponding magnets act, an optical encoder placed apart from the magnetic encoder in an axial direction of the rotation shaft and having an optical scale fixed to the rotation shaft and an optical sensor receiving light reflected by the optical scale, and a substrate placed between the magnets and the optical scale and having one surface with the magnetic sensors mounted thereon and another surface with the optical sensor mounted thereon.

A length measuring instrument for measuring length with a measure includes: a measure on which a code is printed, a plurality of patterns each allotted to a different number being arranged, each of the patterns having digits to which an N-notation number (N being 3 or greater) is allotted, each of the digits having a different color corresponding to the allotted numerical value, the patterns being arranged in ascending order or descending order, a Hamming distance between patterns adjacent to each other in an array direction being 1, an amount of change in numerical value at the same digit between the adjacent patterns being 1 in the code; a reading unit that optically reads patterns printed on the measure; and a measuring unit that measures a length of a measurement target from a result of the reading by the reading unit.

There is provided a light control circuit including a light detector, a frequency detector, an error amplifier, an NMOS driver and a light source. The frequency detector identifies a signal frequency according to detected voltage signals outputted by the light detector and generates a control signal accordingly. The NMOS driver changes a drive current of the light source according to an output of the error amplifier. The error amplifier changes a bandwidth thereof according to the control signal from the frequency detector to regulate a response time of the drive current of the light source.

An assembly comprises a support including a plurality of individual sections. A scale is disposed on the support. The scale extends in a longitudinal direction and has a measuring graduation for position measurement at least in the longitudinal direction. A plurality of fastening devices are configured to fasten the scale to the support. The fastening devices are disposed on the individual sections of the support.

The range of operating angles of a position transducer is widened, and its signal-to-noise ratio is improved. The position transducer includes a light source and a detector including at least one pair of photodiodes (PDs) disposed on a predetermined circle. The detector receives light emitted from the light source to output a signal varying depending on the areas of regions where the light is received on two PDs forming a pair. The PDs are formed on separate chips, respectively, and the chips are disposed on a substrate so that one or more pairs of PDs surround the entirety of a predetermined region and have an annular shape as a whole.

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.