Abstract: Systems and methods for determining an absolute position of a motor of an active front steering system of the vehicle are provided. In particular, the systems and methods accurately determine an absolute position of the motor upon startup of the active front steering system.

Abstract: A reflection encoder is disclosed having a light emitting element in a light receiving element that are separated by a light shielding body that prevents unwanted light from entering the light receiving element. In variations of the invention, the light shielding body may be integrally formed with a mold resin portion that holds the light emitting element and light receiving element, formed by a sheet or plate, or formed using an opaque liquid resin that is poured between transparent resin bodies that encapsulate the light emitter and receiver. In operation, light radiated from the light emitting element is reflected by a code wheel and then received by a light receiving element. Other variations include varying the height at which the light receiving and detecting elements are disposed relative to the code wheel and tilting these elements towards each other so as to increase light efficiency.

Abstract: An optical encoder includes a coding element having a track with a track pattern that comprises multiple optically distinguishable sections. The optical encoder compares photodetector outputs with transition-specific thresholds that correspond to transitions between the optically distinguishable sections of the track. The comparisons are used to determine when the transition between two optically distinguishable sections of the track has passed the photodetector. Knowledge of the transition between two optically distinguishable sections is then translated into digital position information.

Abstract: A system and method of measuring a rotational motion of a code wheel measures a rotational movement of the code wheel including an error component due to a non-rotational movement of the code wheel; measures the non-rotational movement of the code wheel; and produces an error-corrected measurement of the rotational movement of the code wheel by using the measured non-rotational movement of the code wheel to cancel the error component of the measured rotational movement of the code wheel. A signal can be produced indicating a need for maintenance when the non-rotational movement of the code wheel exceeds a threshold.

Abstract: An encoder having a code scale and an emitter detector module is disclosed. The code scale includes alternating reflective and opaque stripes. The emitter-detector module includes a light source that generates light and directs a portion of the generated light to the imaging element and a photodetector that generates a signal representing an intensity of light having a linear polarization in a predetermined direction received by the photodetector, the light source and the photodetector are encapsulated in a transparent medium, wherein there is a gap between the transparent medium and the code scale. The predetermined direction is chosen to reduce the intensity of light received by the photodetector that is reflected from an interface between the transparent medium and the gap. A polarization filter can also be included in the light source to further improve the rejection of the light reflected from the interface of the transparent medium and the gap.

Abstract: A photoelectric encoder of the invention is furnished with a light-emitting element and a light-receiving element for sending and receiving light that are disposed in opposition to one another, and a support member for accommodating the light-emitting element and the light-receiving element. The support member is provided with a through hole between the light-emitting element and the light-receiving element. A code strip in which a plurality of slits have been formed is inserted through the through hole and moved so that it passes between the light-emitting element and the light-receiving element. As a result, light from the light-emitting element is intermittently incident on the light-receiving element through the plurality of slits in the code strip.

Abstract: A photodetector for an optical encoder has plural sets of segmented photodiodes, each set of which is made by two adjoining segmented photodiodes capable of coping with a scale slit having a reference resolution. Output lines of the two adjoining segmented photodiodes are connected together in each set of the photodiodes. These output lines are connected to output lines of the corresponding segmented photodiodes in the other sets. The two adjoining segmented photodiodes function like one segmented photodiode, and thereby, the resolution of the applied scale slit is made ½ of the reference resolution. Thus, this photodetector easily copes with a scale slit having a half resolution of the reference resolution at low cost only by modification of wiring without changing any configuration of the segmented photodiodes.

Abstract: A position-measuring device includes: a measuring graduation provided on a measuring standard device arranged around in ring-like fashion; a scanning unit for optically scanning the measuring graduation using electromagnetic radiation; a scanning plate with a scanning graduation, formed by a scanning grating, extending along a detection axis, which is arranged in the beam path of the electromagnetic radiation used for scanning the measuring graduation, so that the radiation interacts both with the scanning graduation and with the measuring graduation; and a detector of the scanning unit, whose detector surface is used for detecting the electromagnetic radiation after interaction with the scanning graduation and the measuring graduation and which is present as a stripe pattern, in order to record motions of the measuring standard device relative to the scanning unit.

Abstract: Given n move information signals and m slits 22 (n and m: positive integers), the number of photodiodes associated with the m slits 22 is set to n×ma (a: a positive integer). By doing so, all of the (n×ma) photodiodes 23 can necessarily be positioned evenly in units of an equal number against the slits 22 and the move information signals. Also, the photodiodes can be subdivided more than in a conventional optical encoder having photodiodes counting a number represented by m×n, which is a common multiple of the number m of the slits 22 and the number n of move information signals. Thus, with light reception area of each photodiode reduced, shifts, distortions, variations and the like of the move information signals can be suppressed, resolution can be enhanced, and accurate move information signals can be obtained.

Abstract: A photoelectric encoder is provided, which emits light from a light source to a main scale and an index scale that can relatively move with respect to each other and obtains a light-receiving signal by interaction between the main scale and the index scale. The photoelectric encoder uses as the light source an incoherent semiconductor light source (white LED) in which a full width at half maximum of an emission spectrum is wider than that of a monochromatic semiconductor light source. Thus, it is possible to reduce an effect of a gap change on an output signal of the encoder and make positional adjustment easier, thereby improving misalignment characteristics.

Abstract: A signal adjusting apparatus includes a movable member, a setting device, and a prohibiting device. The movable member is movable in a movable range to have the electrical signal adjusted in accordance with a position of the movable member. The setting device sets a prohibition range in the movable range. The prohibition range is a range where a volume level of the electrical signal is to be constant. The prohibiting device prohibits the volume level from being adjusted under the state that the movable member is located in the prohibition range.

Abstract: A scanning unit for an optical position measuring device, the scanning unit having a structured optoelectronic photodetector that includes: a semiconductor substrate, a plurality of radiation-sensitive detector areas, which are arranged next to each other on the semiconductor substrate and a strip conductor, wherein at least a portion of the strip conductor is positioned across a surface defined by the plurality of detector areas and forms a connection with an associated detector area of the plurality of detector areas.

Abstract: An angular offset sensing device includes an optical encoder having a light generating element and a light sensor. An armature includes a reflective surface having a generally semicircular shape and a spectrum of color disposed thereon varying from a first end of the surface to a second end of the surface. A housing encloses both the optical encoder and the armature and rotationally supports the armature. An electrical voltage is generated when light from the light generating element is reflected back to the sensor from the reflective surface. The voltage is proportional to a wavelength of the reflected light and is indicative of an angular rotation of the armature relative to the optical encoder. The voltage is corrected for linearity and used for example to signal a vehicle transfer case shift.

Abstract: First and second signal detecting element groups are respectively arranged to face first and second signal detecting tracks that are provided on a first code wheel. In addition, third and fourth signal detecting element groups are respectively arranged to face third and fourth signal detecting tracks that are provided on a second code wheel. A code string is output from the first and second signal detecting element groups to obtain a circular gray-code for detecting the rotation of the first code wheel within one revolution. Further, a code string is output from the third and fourth signal detecting element groups to obtain a circular gray-code for detecting the rotation of the first code wheel over one revolution.

Abstract: A passive all fiber optic encoder that will be able to determine speed, position, and direction of movement of a movable object. The all passive encoder utilizes no electronics within the sensing part and therefore is deployable in harsh environments, electrical, electromagnetic and radiation fields, otherwise not possible with conventional electronic encoders. The system utilizes a multiwavelength light source and one optical fiber leading to the encoder sensor housing which has a shutter, a light filter assembly and reflective mirror. The movement of the shutter produces a sequential series of light impulses sequenced proportional to the movement of the shutter. The light filter assembly utilizes a minimum of two different filters each of which passes or rejects light within a certain space and wavelength range.

Abstract: A position-measuring device for generating a measuring signal includes a track, which has an incremental graduation having a specified graduation period that extends along a measuring direction, having at least one discontinuity of the incremental graduation at a reference position for generating a reference signal and having a scanning unit movable relative to the track along the measuring direction, for scanning the incremental graduation, the at least one discontinuity formed by a modification of a transverse substructure of the incremental graduation that extends perpendicular to the measuring direction, and that deflects radiation beams originating from the scanning unit. The deflection direction at the discontinuity deviates from the deflection direction in other regions of the incremental graduation. The scanning unit includes at least two reference-pulse detectors provided for receiving radiation beams having a different deflection direction.

Abstract: An optical encoder includes a sensor head, an encoder scale, and an optical wavefront dividing element. The sensor head includes a substrate, a light source, a first optical detector, and a second optical detector. The light source, the first optical detector, and the second optical detector are disposed on the substrate. The scale includes a first track and a second track. The optical wavefront dividing element is disposed between the sensor head and the scale. A light beam emitted by the light source is divided into a first beam and a second beam by the wavefront dividing element. The first beam is incident on the first track and the second beam is incident on the second track. Light from the first beam diffracted by the first track is incident on the first optical detector. Light from the second beam diffracted by the second track is incident on the second optical detector.

Abstract: An Enhanced Reflective Optical Encoder (“EROE”) having an emitter module for transmitting emitted optical radiation to an encoded media and a detector module for receiving reflected optical radiation from the encoded media. The EROE may include a transmissive layer covering both the emitter module and the detector module, and an optical isolation element located within the transmissive layer and located between the emitter module and the detector module. The optical isolation element reduces undesired optical radiation transmitted from the emitter module to the detector module, where the undesired optical radiation is a portion of the emitted optical radiation.

Abstract: A signal adjusting apparatus comprises a movable member, a first detecting device, a second detecting device, and a correction device. The member is movable in a movable range composed of a plurality of intervals. The first detecting device detects one of the intervals where the member is located. The first detecting device is constituted by a first movable portion mounted on the member and a first fixed portion spaced apart from the first movable portion. The one of the intervals is an absolute position. The second detecting device detects a relative position of the member within the detected interval. The second detecting device is constituted by a second movable portion mounted on the member and a second fixed portion spaced apart from the second movable portion. The correction device corrects the detected relative position based on a relationship between the absolute position and the relative position stored in a memory.

Abstract: A system and method for determining the absolute position of a linear or rotary actuator. A code plate having a series of digital words thereon is associated with the linear or rotary actuator. Each of the digital words consists of a plurality of bits, each bit consisting of a series of parallel encoder elements, each in the shape of a wedge. One or two optical sensor heads would be used in conjunction with a signal processor to determine the exact position of the code plate, and, in turn, the linear or rotary actuator. The exact position of each of the sensor heads with respect to the code plate is determined based upon the value of optical signals reflected off of the wedge-shaped elements and detected by each of the optical sensors.

Abstract: A position measuring system that includes a scale having a measuring graduation extending along a first line and a scanning device. The scanning device includes a light source that transmits light beams that scan the measuring graduation, wherein the measuring graduation generates modified light from the transmitted light beams and a detector unit that receives the modified light from the measuring graduation. A lens arrangement, arranged between the scale and the detector unit, the lens arrangement generating a defined image of the measuring graduation on the, detector unit, wherein the defined image extends along a second line, whose curvature is different from a curvature of the first line.

Abstract: A method for position measurement that includes scanning a plurality of graduation periods of one incremental graduation by a detector arrangement extending over a length of one measurement range, a reference marking being integrated with one of the graduation periods, and generating a plurality of periodic scanning signals, of which at least one is locally modified by the reference marking. The method includes detecting the at least one scanning signal, modified by the reference marking, from among the plurality of periodic scanning signals. The method further includes determining an absolute position of the reference marking within the length of said measurement range as a function of the scanning signal detected.

Abstract: In a position measuring system and a method for operating such a position measuring system, e.g., for the purpose of producing at least one reference pulse signal, the position measuring system includes a gauge with a track in which a periodic incremental scale is disposed and extends in one direction of measurement. The track displays a discontinuity with respect to an optical property in at least one defined reference position. The position measuring system further a scanner unit that may be displaced across a predetermined measuring length relative to the gauge in the direction of measurement and that is provided, in addition to a light source, with a plurality of detector elements for the photoelectric scanning of the incremental scale. In adjacent sections of the measuring length, the incremental scale has different transverse substructures that deflect incident ray beams in first and second directions in space.

Abstract: An interferential position measuring arrangement including a light source, which emits a beam of rays and an optical element, which converts the beam of rays emitted by the light source into an incoming beam of rays. A scale grating which splits the incoming beam of rays into a first partial beam of rays and a second partial beam of rays. A first scanning grating that causes splitting of the first partial beam of rays and a second scanning grating that causes splitting of the second partial beam of rays, wherein a periodically modulated interferential fringe pattern with definite spatial interferential fringe pattern period results in a detection plane. A detection arrangement which causes splitting of light entering through the detection arrangement into at least three different spatial directions and optoelectronic detector elements arranged in the at least three spatial directions for detecting phase-shifted scanning signal.

Abstract: A coding element such as a codewheel includes first and second surfaces that are configured with respect to each other and with respect to a light beam such that the light beam is reflected at the two surfaces using the optical phenomenon of total internal reflection. The coding element also includes a coding pattern that is aligned in an optical path of the light beam after the light beam has reflected off of both of the surfaces. A coding element with surfaces that reflect a light beam as a result of total internal reflection can be utilized in an encoding system that operates in transmission while the light source and the photodetector array are located on the same side of the coding element.

Abstract: An optical device that includes a grating (for example a moving reflective grating) and a light source disposed opposing a predetermined side of the grating. The optical device also includes a first reference grating (e.g., a fixed grating) disposed between the light source and the grating, a detector disposed opposing the predetermined side of the grating and a second reference grating (e.g., a fixed grating) disposed between the detector and the grating. The grating, first reference grating and light source are configured for movement relative to one another. For example, the grating can be moveable while the light source and first reference grating are fixed.

Abstract: An angular offset sensing device includes an optical encoder having a light generating element and a light sensor. An armature includes a reflective surface having a generally semicircular shape and a spectrum of color disposed thereon varying from a first end of the surface to a second end of the surface. A housing encloses both the optical encoder and the armature and rotationally supports the armature. An electrical voltage is generated when light from the light generating element is reflected back to the sensor from the reflective surface. The voltage is proportional to a wavelength of the reflected light and is indicative of an angular rotation of the armature relative to the optical encoder. The voltage is corrected for linearity and used for example to signal a vehicle transfer case shift.

Abstract: An angle absolute encoder comprises an encoded code rod that has code marks, such as pairs of fine code lines and coarse code lines. Light is reflected from or transmitted through the code marks and detected by a light detector to determine absolute angle position.

Abstract: A main scale of an optical displacement measuring apparatus has slits arranged on it at regular intervals, a part of which is a missing slit that does not allow light to pass through used for detecting the original point. An index scale has four sets of windows formed on it. The four windows are arranged with mutual phase differences of ¼ P, where P is the pitch of the arrangement of the slits. When a part of the missing slit overlaps with the index scale, no light reaches to photodiodes from the missing slit and only a partial light flux passes through a window, so that the light quantity decreases. An original point signal associated with the missing slit can be obtained by adding up the outputs of all the photodiodes.

Abstract: An encoder calculates position error values and applies compensation values to encoder position measurements in-situ. The encoder includes a scale and a multi-section detector for detecting a spatially periodic pattern, such as an optical interference pattern, produced by the scale. The detector includes spatially separated first and second sections. A signal processor estimates respective phase values from detector sections and calculates a phase difference reflecting a spatial position error in the scale. A compensation value is calculated from the phase difference and included in the estimate of the scale position to compensate for this spatial position error. The compensation values may be calculated and used on the fly, or calculated and saved during an in-situ calibration operation and then utilized during normal operation to compensate uncorrected measurements.

Abstract: A rotary optical encoder is described to provide the pole position of the rotor in a permanently magnetized motor. Using a simple opening design of code tracks and two light sensors along with a corresponding processing circuit, only one additional code track is required on the code wheel to output phase-changing signals. Thus the rotary optical encoder with phase-changing signal with low cost and small size is implemented.

Abstract: A method of using a photosensor as an encoder and a trigger in a production apparatus includes imaging natural surface features of a target, generating data frames of the surface features using the photosensor, processing the data frames to detect movement of the target, and triggering otherwise dormant production components once a movement of the target is detected.

Abstract: A photoelectric encoder includes an optical receipt chip on which a plurality of photodiodes (PDs) are laid out along a measurement axis “X” so that these are organized into an array. The layout pitch of PDs disposed at end portions of the array is made less than the pitch of those at a central portion of the array. Similarly the width of a light acceptance surface of the former is less than that of the latter.

Abstract: An optical phased array transmitter/receiver includes a plurality of waveguides each including an optical fiber and a light source coupled to the fibers in the waveguides. At least one grating is coupled to the fiber of each waveguide and at least one phase shifter coupled to the fiber of at least one waveguide. The phase shifter controls a phase profile of light passing through the fiber to control a profile of a laser beam reflected at the grating. The gratings reflect light passing through the fibers outside of the optical coder to form a laser beam shaped and directed by the grating and phase shifters. Further, a detector is coupled to the waveguides that is enabled to receive light reflected off the gratings. Other embodiments are described and claimed.

Abstract: A method for position determination that includes generating first and second position-dependent scanning signals, transmitting the first and second position-dependent scanning signals from a scanning location via corresponding first and second scanning channels to corresponding first and second storage elements, storing corresponding first and second instantaneous values present at the first and second storage elements at corresponding first and second storage times. Forming a measured position value from the first stored instantaneous value and the second stored instantaneous value. A difference exists between corresponding first and second transit times of the first and second position-dependent scanning signals in the corresponding first and second scanning channels, the difference is compensated by individually delaying the first and second position-dependent scanning signals, so that the stored first and second instantaneous values have appeared at a common time at the scanning location.

Abstract: A P-ECU controls an actuator which drives a shift control mechanism. An encoder signal acquisition unit acquires signals output from an encoder which detects a rotational angle of the actuator. A counter calculates a count value from the output signals of the encoder. An energization control unit controls energization to the actuator. A first phase-matching unit uses the Z-phase signal of the encoder to match the count value with energized phases so as to find a correspondence therebetween and a second phase-matching unit matches the count value with energized phases to find a correspondence therebetween without using the Z-phase signal of the encoder. If the first phase-matching unit detects an abnormality of the encoder, the second phase-matching unit subsequently performs phase matching.

Abstract: A code disk, an optical encoder using such a disk and a method thereof are described. The code disk includes a first region on the disk and a second region that is adjacent to the first region. The first region increases continuously in size in a radial direction from a minimum at a first angular position to a maximum that occurs 360 degrees from the first angular position. One of the first and second regions allows light to be transmitted therethrough to a detector, and the other of the first and second regions prevents light from being transmitted therethrough. The detector generates an output that corresponds to the amount of light transmitted through the code disk.

Abstract: A position control method by motor drive including of rotating a rotor of the motor drive according to the given target opening, and detecting the opening of a movable vane by an encoder, the motor drive opening and shutting a passage of an intake air pipe to a turbo charger of the automobile by the movable vane, and controlling the movable vane in the passage of the intake air pipe so that it reaches the target opening. The rotational position of the motor drive is controlled to the stop position in the direction where the movable vane is closed and the stop position in the direction where the movable vane is opened. The motor drive is controlled so that the passage of the intake air pipe becomes the target opening by setting the stop position as an operation reference position of the motor drive, and setting between the stop positions as the driving dynamic range motor drive.

Abstract: A method for optical measuring data acquisition of a component that moves in a rotary or translatory manner, in particular for optical angle, torque, or distance measurement, includes generation of a first pair of periodic line patterns extending in the movement direction of the component and a second pair of periodic line patterns extending in the movement direction of the component, which each have m periods, in particular n+1 periods, over the movement range of the moving component determination of respective phases of the line patterns of the first pair and of the second pair, determination of the phase position of the first pair of line patterns on the basis of the phases and of the second pair of line patterns on the basis of the phases, and determination of the position of the component on the basis of the phase positions.

Abstract: Three rotation sensors circumferentially arranged at 90 degree intervals in a disk code wheel attached to a motor's output shaft respectively output a signal corresponding the rotational speed of the wheel. An error component of one period (one-periodic component) or an error component of two period (two-periodic component) is generated per rotation when the code wheel is eccentric to the output shaft or is elliptically deformed, respectively. Control means averages the signals of the first and second sensors to obtain a first correction signal and subtracts the signal of the third sensor from the signal of the first sensor to obtain a second correction signal while removing the two-periodic component. The control means subtracts or adds the first correction signal relative to the second correction signal upon coinciding these signals in phase and amplitude to calculate a rotation measurement signal from which the periodic components are removed.

Abstract: An apparatus and a method of the present invention positions an optical component among several optical components, which are arranged in a receiving device. The receiving device is rotatable about an axis or movable along a direction in such a way that an optical component is positionable and the receiving device is retainable in a retention position. A coding device having first and second coders and two detectors are also provided. Either the coding device or the two detectors are associated with the receiving device and the two detectors detect the first and second coders at spatially different points. The coding device is embodied in such a way that the two detectors detect the first coder simultaneously when the receiving device is in a retention position and no more than one detector detects the second coder when the receiving device is in a region between two adjacent retention positions.

Abstract: A position measuring device having a scanning device and a scale, wherein the scanning device is movable in relation to the scale in a measuring direction. The scale including a measuring graduation, wherein periodic measuring signals are generated when the scanning device scans the measuring graduation and a reference marking, wherein a reference marking signal is generated when the scanning device scans the reference marking with a scanning beam bundle. The scale further includes a first optically scannable area marking next to the reference marking and a second optically scannable area marking next to the reference marking and which has a different optical deflection property than the first optically scannable area marking, wherein photoelectric scanning of the first and second optically scannable area markings with the scanning beam bundle from the scanning device generates an area signal that differentiates characteristics of the first and second optically scannable area markings.

Abstract: A rotary type encoder is provided with a signal generating portion 2 for generating a sine wave signal of N periods for each revolution in accordance with the rotation of the shaft 4 of a motor; a calculation means for obtaining the rotation angle of the shaft 4 based on the sine wave signal; an EEPROM 37 being arranged in a manner that the error value of the rotation angle for one revolution of the shaft 4 thus measured is divided in relation with the N periods to set a plurality of first angle regions i, the angle region almost at the center of the angle region i is divided into plural regions to set second angle regions j, and an error value corresponding to the angle at almost the center of each of the angle regions j is stored therein in correspondence with the rotation angle; and a correction means for reading the error value stored in the EEPROM 37 in correspondence with the rotation angle to correct the rotation angle.

Abstract: The present invention relates to a device for accomplishing noise reduction in a photoacoustic gas detector using a sound damping element and/or a background or reference microphone where a preferably larger external volume that acts as a sound damping element (SDE) is coupled to a smaller volume through which the gas diffuses. The coupling is accomplished in such a way that the externally generated sound waves incident upon the photoacoustic detector are adequately attenuated by the larger volume SDE without adversely affecting diffusion of the gaseous species of interest through the smaller volume for measurement by the detector. Preferably this is accomplished by coupling the larger SDE volume to the smaller gas diffusion volume by a long and thin pressure channel.

Abstract: An angular position sensor (1) suitable for use in combination with the rotor of an electric motor comprising both absolute and incremental encoders (3) where a first signal of the absolute encoder produces a period corresponding to an electric revolution of the motor and less than a mechanical revolution of the rotor, a second output of the incremental encoder varies periodically over a complete revolution of the rotor, where the two signals provide sufficient information to determine the absolute mechanical position of the rotor. Typically, transitions in the first output signal combined with the state of the second output signal provide such information.

Abstract: A rotary encoder includes a roller having substantially cylindrical shape, an inner shaft, a translucent cylindrical light guide shaft, a pair of holders, a light-emitting device, and a light-detecting device. The inner shaft is inserted and secured to a center hole of the roller, and has a slit at one end along a direction parallel to the axis thereof. The light guide shaft is inserted in the inner shaft so that one end of it is surrounded by the slit, and this guide has a first and second planes, and a first and second inclined planes. The first and second planes are formed on a lower side at both ends of the light guide shaft in parallel to the axis of the shaft. The first and second inclined planes are formed above the first and second planes at an angle of 45 degrees to the axis of the shaft, so that the two planes are substantially orthogonal to each other.

Abstract: An optical encoder device (100) comprises: an optical emitter (103) for emitting light, the optical emitter (103) having a light emission direction (E); an optical detector (104) for detecting light emitted by the optical emitter (103), the optical detector (104) having a light detection direction (D) which is different from the light emission direction (E); an optical element (109) for controlling an optical path (108) between the optical emitter (103) and the optical detector (104) such that light emitted by the optical emitter (103) can be detected by the optical detector (104); and a free area (113) in the optical encoder device (100) for accommodating a moveable optical encoding unit (112) comprising a plurality of alternating transparent and opaque encoding elements such that the plurality of alternating transparent and opaque encoding elements of the optical encoding unit (112) is able to affect the optical path (108).

Abstract: The present invention relates to a method for determining a home position by means of a home position mark on a special microfluidic device type used in a microfluidic system. The method for determining a home position by means of a home position mark on a microfluidic device used in a microfluidic system comprising at least one programmable controller having storage means, a position device being able to communicate with the controller, and a home position mark detector connected to said controller, wherein said method comprises the following steps: scanning a disc for mark edges; rejecting false home mark(s) and identifying a correct home position mark; and determining a home position by use of mark edges of the correct home position mark identified in the previous step. The present invention also relates to a microfluidic system and a computer program product and a computer program product on a computer usable medium.

Abstract: A position measuring system that includes a scale and a scanning device that scans the scale. A light source, which emits a light pulse upon receipt of a request signal and an optical fiber that transmits the light pulse from the light source to the scanning device and for illuminating the scale. At least one photo detector that detects the light pulse affected by the scale as a function of its position.

Abstract: A photoelectric rotary encoder includes a light source that emits a light beam, a returning section that returns the emitted light beam to a direction opposite to an emitting direction of the beam, and a photodetector that is disposed on a substrate on which the light source is disposed and that detects the returned light beam via a disk having a detection pattern section. The photoelectric rotary encoder detects rotational displacement of the disk based on the detected returned light beam. In this photoelectric rotary encoder, an optical element that lets a stray beam component of the light beam from the light source escape via a side surface of the optical element, is disposed in front of the substrate on which the light source and the photodetector are disposed. The optical element covers the substrate and integrates the optical element and the substrate.