The position detection apparatus includes the first optical position detector used with an optical scale having periodic patterns. The first position detector receives lights from the periodic patterns when moving relatively to the optical scale with a movement of a movable member to generate first detection signals respectively changing at periods corresponding to periods of the periodic patterns. The second non-optical position detector generates a second detection signal changing with the movement of the movable member. The calculator produces a first position signal by using the first detection signals, produces a second position signal whose resolution is different from that of the first position signal, by using the second detection signal, and performs a calculation for combining the first and second position signals together to produce an absolute position signal.

Some embodiments of the invention include an area position code pattern, comprising an arrangement of code marks in a basic grid. At least one portion of said position code pattern is readable by a matrix sensor for determining positions. According to some embodiments of the invention, the position code pattern is embodied with a first absolute code sequence in a stringing-together of the code marks in a first line direction of the basic grid as first line on the area to be encoded and the code marks are encoded with a second absolute code sequence in the line direction along a second line which follows the first line. The first line and the second line form a line pair and the two absolute code sequences are each arranged offset in the first direction in the basic grid in a subsequent line pair.

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 origin detector includes detecting element groups having a first to a fourth detector, is configured so that a first signal sensitivity of the detectors of a center is larger than a second signal sensitivity of the detectors of a periphery, reads an origin detecting pattern including an origin pattern having a length along a detecting direction of a part having a physical characteristic different from an origin peripheral part larger than a length along the detecting direction of each detecting element group, and outputs a first signal using the first and third detectors, and a second signal using the second and fourth detectors. A processor acquires a third signal from the first signal and a first threshold, and a fourth signal from the second signal and a second threshold, and outputs a fifth signal using the third and fourth signals as an origin signal.

A scale is provided with a two-level code pattern according to a pseudo random code sequence along a length measurement direction. Each code of the two-level code pattern indicates a code 1 or 0, each code includes two bits, and each bit of the two bits is L or H. The code 1 is represented by an A pattern which is a combination of L and H, and the code 0 is represented by a B pattern which is a combination of L and L or by a C pattern which is a combination of H and H. When the codes 0 are continued, the B pattern and the C pattern are alternately used. The scale is commonly used in a reflective type encoder or transmissive type encoder. A detection head part includes an inversion processing unit which performs inversion processing to a detection image of the scale as required.

Embodiment of the present invention provides various types of optical measurement scaleplates, optical measurement apparatus and method using the optical measurement scaleplates for position measurements. In one embodiment, an optical measurement scaleplate has a substrate and a plurality of marking units each being borne on the substrate at a predetermined position. Each marking unit includes a plurality of optically detectable marking elements. Each of said marking elements has an element value defined a permutation of the element value of each of the marking elements in said marking unit, and each unit value corresponds to a physical quantity. On the substrate there is defined a first direction. The physical quantity includes a first distance between a reference position and said predetermined position along the first direction.

A position detector, including: a scale including a pattern array formed cyclically in a movement direction, the scale being provided to a fixed member or a movable member; a detector including detection elements arranged in the movement direction, the detector being provided to the other; a generating unit that selectively generates, from signals received from the detection elements, a first signal obtained by a first combination of the signals or a second signal obtained by a second combination of the signals; an output unit that outputs the first or second signal received from the generating unit; and a switcher that switches over between the first and second signals as a signal to be generated, wherein the first signal changes within a first range, corresponding to a relative position; and the second signal does not change beyond a second range smaller than the first range, corresponding to the relative position.

An electronic absolute position encoder is provided including a scale, a detector portion and a signal processing configuration. The scale includes a first scale pattern of signal modulating elements, wherein the first scale pattern includes a spatial characteristic of the signal modulating elements which progressively changes as a function of position along a measuring axis direction and defines an absolute measuring range. The spatial characteristic includes at least one of a spatial wavelength or a spatial frequency of the signal modulating elements and is unique at each unique position in the absolute measuring range. The detector portion includes a group of sensing elements, and the signal processing configuration determines an absolute position of the sensing elements relative to the scale within the absolute measuring range. In various implementations, the signal processing configuration may utilize Fourier transform processing and/or other processing for determining the absolute position.

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.

An optical encoder is disclosed. Specifically, a reflective encoder is disclosed that includes an emitter configured to emit light, a first detector configured to receive a first portion of the light emitted by the emitter and convert the received first portion of the light into one or more electrical signals, the received first portion of the light at least one of passing through and being reflected by an optical track of a coding element. The reflective encoder also includes a second detector configured to receive second portion of the light emitted by the emitter and convert the received second portion of the light into one or more electrical signals, the emitter is positioned between the first detector and the second detector such that a first light path between the emitter and first detector is approximately a same distance as a second light path between the emitter and the second detector.