An encoder includes a measurement target and circuitry. The measurement target includes an absolute pattern and is rotatable. The circuitry is configured to generate, via a processing scheme, a signal representing an absolute position of the measurement target based on the absolute pattern. The circuitry is configured to detect, based on the absolute pattern, whether the measurement target rotates or not. The circuitry is configured to change the processing scheme based on whether the measurement target rotates or not.

An optical encoder system is disclosed comprising a movable target arranged to provide a varying reflectance dependent on a position of the target within the system. An emitter is positioned on a first side of the target to illuminate the target and a sensor is positioned on the first side of the target to sense a reflectance from the target, wherein the sensed reflectance is dependent on the position of the target within the system. Also disclosed are a target and a sensor module for use in such a system, a device comprising such a system and a method of determining the position of a moving target using such a system.

For providing an apparatus and method for providing a graphic representation (1) or a graphic representation sequence for detection by a detector (3) which provide a simple and effective variation of a graphic representation (1) or a graphic representation sequence for detection by the detector (3) an apparatus is claimed, comprising: a sequence of graphic representations (1) along an optical axis (2), an optical device (4) for focusing on at least one of the graphic representations (1), so that the at least one of the graphic representations (1) is visible by a detector (3) preferably with a predefinable sharpness, a control unit (5) for defining and providing a focusing sequence on the at least one of the graphic representations (1) by the optical device (4) for providing a change of visibility of the graphic representations (1) or of a part of the graphic representations (1) by the detector (3) in order to allow for the verification of the correct functioning of the detector.

A sealed encoder module for mounting onto a machine so as to measure relative displacement of first and second parts of the machine. The sealed encoder module can comprise, a scale, a readhead comprising a scale signal receiver, and an integral protective housing which encapsulates at least the scale and said scale signal receiver. The sealed encoder module can be configured to determine and output diagnostic information regarding a scale signal detected by the readhead.

A position detection encoder includes a scale that has a position detection pattern and a linear pattern that is formed in a direction parallel to a length direction of the position detection pattern; and a position detector generating a position detection signal with a different value due to a displacement of the position detection pattern in the length direction. In the position detector, a position confirmation pattern is formed that includes two markers arranged at an interval equal to or less than an offset tolerance value for a positional relationship of the position detector and the scale in a width direction of the position detection pattern.

The present invention provides a position detection apparatus that is provided with a scale and a detector and includes a processing unit configured to perform processing for setting a number of light receiving elements that are consecutive in a direction of relative movement and whose outputs are to be added for the light receiving elements so that, in a first resolution mode, a phase of a component of a fourth spatial frequency lower than a spatial frequency corresponding to a frequency offset amount is detected and, in a second resolution mode for which a resolution is lower than the first resolution mode, a phase of a component of a spatial frequency of an interference image of a second grating pattern is detected.

In order to provide a small detection device capable of detecting an accurate absolute position with a single head, there is provided a detection device including a head including a light source and a detecting unit configured to receive multiplexed light (interference light) of diffracted light obtained by causing light from the light source to enter first two points residing on ax diffraction grating and being separated from each other by a known distance and diffracted light obtained by causing the light from the light source to enter second two points residing on the diffraction grating, being separated from each other by a known distance, and including at least one point being different from the first two points, wherein the diffraction grating includes a first region between the first two points separated from each other by the known distance and a second region between the second two points separated from each other by the known distance, the first and second regions having at least partially different grating interval lengths, and an absolute position on the diffraction grating is detected based on the multiplexed light (interference light) received by the detecting unit.

Provided is an angle detection system including an encoder pattern portion attached to a measuring object, and a surveying instrument. The encoder pattern portion includes an encoder pattern provided on an outer circumferential surface of a columnar base and representing an angle with respect to a predetermined reference direction. The encoder pattern includes a reflective material layer and an encoder pattern layer. The encoder pattern layer includes a combination of a first and a second polarization filter. The surveying instrument includes a reading light transmission unit for configured to outputting reading light toward the encoder pattern, an information acquiring unit to for optically acquiring information represented by the encoder pattern, an arithmetic control unit for calculating an angle of the surveying instrument with respect to the reference direction, and a first or second polarization filter disposed on an optical path of the reading light to enter a light receiving surface of the information acquiring unit.

An optical sensor for a delivery device having a piston that displaces a substance, such as a fluid, from a reservoir. The optical sensor has a light source and a detector array for imaging encoding features disposed along a plunger rod coupled to the piston. By virtue of the pattern of encoding features, an absolute position of the plunger rod relative to a fiducial position may be determined uniquely. Thus, the volume of fluid remaining in the reservoir, the rate of fluid delivery, and proper loading of the reservoir may be accurately ascertained. Additionally, the encoding may serve to uniquely identify a version of the reservoir which may be supplied in various versions corresponding, for example, to differing concentrations of a therapeutic agent to be dispensed.

An encoder apparatus comprising a scale and a readhead assembly comprising a scale signal receiver. The scale and the scale signal receiver are located within a protective housing which is configured to protect them from contamination located outside the protective housing and comprises a seal through which the scale signal receiver can be connected to a part outside the protective housing. The arrangement of the scale signal receiver inside the protective housing is independent of the scale and protective housing.