Abstract: An optical motion encoder for translation of movement information into a digital output. The optical encoder includes an optical member having a parabolic reflecting surface and a planar surface with a code pattern printed thereon. The light rays received by the parabolic reflecting surface from a light source positioned on the axis of symmetry of the parabolic reflecting surface are reflected as parallel light rays through the planar surface to be modulated by the code pattern and detected by a light detector. In this way, both, the collimator and the code wheel or code strip of prior art optical encoders are represented by a single optical member.

Abstract: An encoder including a light source for emitting light, a photodetector for detecting at least part of the light emitted by the light source, and an encoder film including a plurality of alternating bars and windows and being located between the light source and the photodetector. The encoder includes a mask including a plurality of alternating bars and windows, the mask being located between the light source and the photodetector. The encoder further includes a spacer located between the mask and the encoder film, the encoder film contacting the spacer to maintain a predetermined spacing between the mask and the encoder film.

Abstract: A scanning head is described, having on a side facing a scale at least one patterned photodetector, which is realized in a semiconductor substrate. The semiconductor substrate has an anisotropic blind hole that is symmetrical to the several photodetectors, and a light source arranged on a base plate in the blind hole. The transmitting grating for the light source is formed either in a metallization layer on the semiconductor substrate or, in the form of bars of the semiconductor substrate that have not been etched away. The distance between the scale and the transmitting grating as well as the distances between the scale and the patterned photodetector are essentially the same.

Abstract: An electronic circuit for measuring the position of a spatially periodic intensity pattern of incident radiation includes an array of detectors (1); two or more correlator units (2, 3) each having arrays of capacitors (12, 13) connected to a buffer (14); and a phase angle computing unit (4). The pitch of the array of detectors (1) is smaller than the pitch of the incident intensity pattern so that the latter is oversampled, yielding high accuracy. The detector outputs (17) are weighted by respective fixed capacitance values (15, 16) which vary periodically along arrays of capacitors (12, 13), and a weighted sum of outputs for each correlator unit (2, 3) is output at its respective buffer (14). The capacitance values (15, 16) of respective correlator units (2, 3) are mutually offset by a predetermined phase shift. The analog computation using capacitor arrays (12, 13) is fast and energy efficient, and can be implemented as a VLSI circuit.

Abstract: A position of a sensing head, which contains at least one sensor, is measured with respect to a scale embodiment which contains a linear code. The measurement is performed such that a predefined resolution is achieved. Firstly, an absolute value of an initial position is determined with at least the predefined resolution, for example by evaluating the signals from all the sensors at a standstill. During the measurement, the sensing head and the scale embodiment are moved relative to each other. Fewer sensors are used than would be needed at a standstill, for example, only a single sensor is used. The information needed to achieve the predefined resolution is obtained from sensor signals of the relative movement, which are derived from the linear code. In this way, a signal for the absolute position and the number of revolutions is determined, even at high speeds. The limits set by signal processing and signal transmission are much higher than in the case of known measurement transmitters.

Abstract: A position measuring system that includes a scale having an incremental track, which extends in a measuring direction and has an incremental graduation with two different graduation periods. A scanning unit moves in relation to the scale in a measuring direction, the scanning unit has an incremental signal detection arrangement, wherein the incremental signal detection arrangement generates incremental signals with a first coarse signal period and generates incremental signals with a second finer signal period.

Abstract: An apparatus for determining the position of a mechanical element wherein the mechanical element is marked in an optically readable manner, comprising reading means to provide a first output dependent on the position of the mechanical element.

Abstract: In incremental detectors, measurement signals thereof are first corrected in graduation-specific fashion with respect to amplitude offsets, and phase displacement, and a rough angle is determined. The residual error of the rough angle is fine-corrected via rough-angle-specific, graduation-independent rough angle correction values and a position signal is determined in this way. The correction values for amplitudes offsets, and phase displacement are determined using regression, and the rough angle correction values are determined using high-precision reference angle measurements.