Provided is a photoelectric encoder that can achieve higher accuracy while maintaining reliability by reducing stray light. An encoder 1 is a photoelectric encoder including a light source device 2 that emits parallel light, a scale 3 having calibrations C provided along a measurement direction, and a light receiving unit 4 that receives light being emitted from the light source device 2, and transmitted through the scale 3. The encoder 1 includes an antireflection member 30 that prevents stray light generated by being reflected on the scale 3, from entering the light receiving unit 4. Because the encoder 1 includes the antireflection member 30, the encoder 1 can achieve higher accuracy while maintaining reliability by reducing stray light entering the light receiving unit 4.

A method of compensating errors in a coordinate measuring machine adapted for determination of at least one spatial coordinate of a measurement point on an object to be measured. The method comprises measuring a distance from the first reference element to the first structural component, wherein the measured distance indicates a displacement or a deformation of the first structural component, defining a dynamic model with a first set of state variables, the state variables being related to a set of physical properties of the reference module and representing an actual state of the reference module, deriving the actual state of the reference module by a calculation based on the dynamic model, and deducing compensation parameters based on the actual state.

A sensor unit for measuring the position of a component that is movable relative to the sensor unit includes a metal body, which has a first opening. An electronic component is arranged in the first opening such that a gap is provided between the electronic component and the metal body, the gap being filled with an electrically insulating molding compound. In addition, an electrically insulating first layer is applied on the electronic component and on the molding compound. The electronic component is electrically contacted with a circuit trace, and the circuit trace is routed through the first layer in a first section and extends on the first layer in a second section.

A shaft may be rotated, where the shaft includes an encoder with a first, second, and third logical track, where the first and second logical tracks include bit patterns that are readable to be 90 degrees out of phase with one another, and where the third logical track includes a sequence of n numbers, each number being represented by m bits, where n is greater than 1. While moving the shaft, a number of the sequence from the third logical track and an extent of bits from the first or second logical track may be read. An orientation of the shaft may then be determined based on the number and the extent of bits. The orientation may be a linear position of a linear encoder or an angular position of a rotary encoder.

An encoder scale includes a plate-shaped base mount and an optical pattern that is provided on one surface of the base mount and has alternately arranged first regions and second regions. The first regions are each primarily formed of a first surface a normal to which extends in the thickness direction of the base mount, and the second regions are each primarily formed of a second surface that inclines with respect to the first surface.

An optical encoder includes a scale including a diffraction grating, a light-receiving unit configured to receive light from a light source, and an optical element located between the scale and the light-receiving unit. The optical element includes a plurality of groove portions, which are a periodic structure portion formed periodically in one face of the optical element. The plurality of groove portions is configured to divide signal diffracted light and noise diffracted light into first splitted beams traveling at a predetermined travel angle and second splitted beams traveling at a travel angle greater than the travel angle of the first splitted beams, and make a diffraction efficiency of the first splitted beams of the noise diffracted light lower than a diffraction efficiency of the first splitted beams of the signal diffracted light.

An absolute-type linear encoder absolute signal consistency correction method, related to the field of absolute-type linear encoder measurements, for solving the problem of narrow linear range for photoelectric responses and large signal dispersion found in an existing consistency correction method for a photoelectric conversion component and a processing circuit thereof. The correction method allows for enhanced absolute signal quality and increased system measurement precision.

A detection head movable relative to a scale detects diffracted light and outputs a detection result. The diffracted light is diffracted by an incremental pattern. A signal processing unit calculates a relative displacement between the scale and the detection head. The detection head includes: a light source emitting the light to the scale; and a detection unit including a light-receiving unit receiving the diffracted light through an optical element, in which the light-receiving elements outputting detection signals are periodically arranged with a predetermined period. The number of the plurality of light-receiving elements is an even number. The predetermined period is a value obtained by multiplying a fundamental period by an odd-number. The fundamental period is a period of interference fringes formed on the light-receiving unit by +1st and 1st order diffracted lights. A width of the light-receiving element is not equal to an integral multiple of the fundamental period.

A method for compensating for accuracy errors of a hexapod is disclosed, said hexapod comprising a base, an actuation assembly having six linear translation actuators, a control unit, and a movable carriage comprising a platform connected to the base by means of the actuation assembly. The method includes a measurement step for determining geometry and positioning errors on the hexapod, the measurement step including sub-steps for determining positioning errors of the pivot centers on the carriage and on the base, for determining length errors of the actuators and for measuring positioning errors of the actuators along the path thereof, the compensation method also including a step for calculating, from measurements taken, error compensation values and a step for applying said error compensation values to the control unit of the hexapod, during subsequent use of said hexapod.

A detection head movable relative to a scale detects diffracted light and outputs a detection result. The diffracted light is diffracted by an incremental pattern. A signal processing unit calculates a relative displacement between the scale and the detection head. The detection head includes: a light source emitting the light to the scale; and a detection unit including a light-receiving unit in which a plurality of light-receiving elements that output a detection signal are arranged. The number of the plurality of light-receiving elements is an even number. A period of the arrangement of the plurality of light-receiving elements is an odd-number multiple of a fundamental period. The fundamental period is a period of interference fringes formed on the light-receiving unit by +1st and 1st order diffracted lights. A width of the light-receiving element is not equal to an integral multiple of the fundamental period.