Abstract: An optical encoder is disclosed. Specifically, a three-channel encoder is disclosed which utilizes a single track for all three channels. An index channel is provided on the same optical track as the first and second channels which are used to determine incremental angular position. Thus, a more compact and simple three-channel encoder is provided.

Abstract: An optical encoder may include an encoder disk, an illumination system, and a detector to detect light diffracted from the encoder disk. The encoder disk may include a signal track comprising a diffraction grating, and an index track comprising a reflective index mark, wherein a width of the index mark is larger than a pitch of the diffraction grating. An indexing method may include providing an encoder disk, providing an illumination system to direct light to the encoder disk, providing a detector structured to detect light diffracted from the encoder disk, calculating an estimated count of quadrature states from a rising edge of an index pulse to a middle of the index interval, and calculating the quadrature state at an approximate center of the index pulse. A dynamic parameter correction method may include calculating a target gain and offset and correcting values based on the target gain and offset.

Abstract: A rotary encoder 100 includes a scale 201 that includes a spiral pattern 501 and a radial pattern 502 to be rotatable around a rotation axis, a first sensor unit 301 that detects a light transmitted through the spiral pattern 501 to output a first detection signal, a second sensor unit 302 that detects a light transmitted through the radial pattern 502 to output a second detection signal, and a signal processing circuit 401 that generates an eccentricity correction signal based on the first detection signal to correct the second detection signal based on the eccentricity correction signal. The spiral pattern 501 detects a rotational angular displacement larger than a predetermined value, and the radial pattern 502 detects a rotational angular displacement smaller than the rotational angular displacement detected by the spiral pattern 501.

Abstract: An encoder and method for precisely indicating the position of a first member with respect to a second member by utilizing a pattern of machine-sensible elements carried on a single track of the first member; the machine-sensible elements being located at successive incremental rotations on the track of the first member and each representing one of the binary values “0” and “1”; and a plurality of “n” sensors, wherein “n” is greater than “3”, carried by the second member at a plurality of spaced locations thereon in proximity to the track of the first member and alignable with the machine-sensible elements of the first member.

Abstract: A method and apparatus for suppressing loss of scale image contrast due to interference effects from optical path length differences, including lens profile aberrations, are provided in a displacement sensing optical encoder that uses a telecentric imaging configuration. According to the invention, the encoder is configured such that the image light that reaches the detector comprises symmetric ray bundles concentrated symmetrically on opposite sides of the optical axis center at the limiting aperture of the telecentric imaging configuration. Central ray bundles, and/or other ray bundles that have an optical path lengths significantly different than the operational symmetric ray bundles are prevented or blocked. As a result destructive interference is prevented and image contrast is improved.

Abstract: An optical encoder may include an encoder disk, an illumination system, and a detector to detect light diffracted from the encoder disk. The encoder disk may include a signal track comprising a diffraction grating, and an index track comprising a reflective index mark, wherein a width of the index mark is larger than a pitch of the diffraction grating. An indexing method may include providing an encoder disk, providing an illumination system to direct light to the encoder disk, providing a detector structured to detect light diffracted from the encoder disk, calculating an estimated count of quadrature states from a rising edge of an index pulse to a middle of the index interval, and calculating the quadrature state at an approximate center of the index pulse. A dynamic parameter correction method may include calculating a target gain and offset and correcting values based on the target gain and offset.

Abstract: A rotary position detector includes a housing having an inner space having a reflective element. A light source emits light rays upwardly. A base supports a light detector assembly having a first number of toroidal-sector-shaped light sensors disposed in pairs about a motor shaft axis, one “A” detector element and one “B” detector element alternately disposed. A light blocker positioned between the light source and the light sensors rotates with the shaft. The light blocker includes a second number of opaque, equal-surface-area elements arrayed about the axis, the second number equal to one-half the first number. A circuit measures a signal from the “A” and “B” detectors relating to an amount of light falling thereon, a difference related to an angular position of the motor shaft.

Abstract: An optical entire-circumference encoder includes a substrate. A light source is disposed on a rotation axis and a first surface of the substrate. A disc, rotatable about the rotation axis, is disposed on a second surface of the substrate. The disc includes first and second rotation tracks each including rotating slits. A light guiding unit radially guides light from the light source toward an entire outer circumference of the disc to the first and second rotation tracks. The light guiding unit includes a first light guiding section and second light guiding sections. The first light guiding section includes a ring-shaped surface directly or indirectly opposed to a rotation track. The first light guiding section radially guides the light out from the ring-shaped surface toward the first rotation track. The second light guiding sections guide part of the radially guided light to the second rotation track.

Abstract: A sensor for sensing the angular position of a rotor includes a code disk rotatable with the rotor. A first light guide is rotatable with the rotor. The light guide directs light from a light source through the code disk to a detector. A second light guide has first and second arms directing light from a light source to the detector. A light modulator modulates the light directed from one of the first and second arms to the detector. A method for determining the angular position of the rotor includes providing the code disk with a plurality of individual designation areas located near the outer peripheral edge of the disk. Each designation area has a plurality of digital bits. The detector detects the digital bits from a selected portion of the code disk. The selected portion is functionally related to the angular position of the rotor. A bit center is determined for each bit of the selected portion.

Abstract: A system and method for measuring linear and angular displacement of a moving object, such as an autonomous moving object. In one embodiment, the system comprises at least one optical mouse sensor mounted adjacent to and at a predetermined distance from a surface of the autonomous moving object or a working surface. A processor on the autonomous moving object is operatively coupled to the optical mouse sensor. The optical mouse sensor outputs linear and angular displacement values to the processor during movement of the autonomous moving object to determine a direction and distance traveled by the autonomous moving object.

Abstract: The present invention provides a speed detection device comprising: a detected body that includes a plurality of marks arranged along a first direction with intervals therebetween; a detection section that detects intervals of times of appearance of the marks when the detected body relatively moves in the first direction; and a calculation section that calculates a speed of relative movement of the detection section and the detected body on the basis of results of measuring displacements from a reference plane in a second direction, which is orthogonal to the first direction, of locations of the detected body along the first direction and the detected intervals of times of appearance of the marks.

Abstract: A position sensing system controls selection of channels in a KVM switch having a plurality of channels. The system has a sensor interface for receiving a sensor reading indicating a current position of a position movable component. Each position of the movable component is associated with one of the plurality of channels. The position sensing system also includes a position component for selecting channels of the KVM switch according to the sensor reading. The position component comprises a position definition component and a translation component. The definition component identifies one of the channels corresponding to the sensor reading based on one of a position definition. Each position definition provides sensor readings corresponding to the positions associated with one of the channels. The translation component generates a signal for selecting the determined channel at the KVM switch. This signal is provided to the KVM switch to switch the KVM channel.

Abstract: A complex-operation input device having an operable knob held in a rotatable and slidable manner includes a rotation sensor that detects rotation of the operable knob on the basis of displacement of a second detected portion, and a slide sensor that detects sliding of the operable knob on the basis of displacement of a first detected portion. The direction in which the second detected portion moves with the sliding of the operable knob is substantially orthogonal to a rotation axis about which the operable knob rotates. The slide sensor is disposed such that, when the operable knob is slid, the slide sensor detects the sliding before the rotation sensor detects the displacement of the second detected portion.

Abstract: An angular correction method is provided for a rotary encoder in which angular skip does not occur in determining an angle at a position of switching a combination of successive angular graduation images used in interpolation calculation. An angular correction quantity Ci includes (1) a residual ri between a position computed from a model and an actually read position P, for each angular graduation image position and (2) a tangential slope f?(xi) of residual curve, r=f(x), determined by fitting the residuals to a polynomial f(x) which is a function of angular graduation image number x. The actually-read position P is corrected as P+Ci to perform interpolation calculation determining an angle without angular skip.

Abstract: Disclosed are various embodiments of a single track reflective optical encoder featuring current amplifiers disposed in the signal generating circuit thereof. Voltage amplifiers and their associated feedback resistors are eliminated in the various embodiments disclosed herein, resulting in decreased die size and improved encoder signal accuracy and performance, especially at high speeds The single track optical encoder configurations disclosed herein permit very high resolution reflective optical encoders in small packages to be provided. Methods of making and using such optical encoders are also disclosed.

Abstract: A photoelectric encoder includes: a scale having a grating formed with a predetermined period Ps; and a detector head being movable relative to the scale and including a light source and a light receiving unit. In a configuration where light receiving elements in the light receiving unit output N-points light and dark signals (N is an integer of 3 or more), and where phases of the N-points light and dark signals are detected by a least-squares method to fit a sinusoidal function with fixed period to N-points digital signals digitized from the N-points light and dark signals, an N-points light and dark signal period P is set at an integral multiple of a data-point interval w of the N-points digital signals, and an overall length M of the light receiving elements is set at an integral multiple of the N-points light and dark signal period P. Thereby, position detecting errors occurring due to a stain of the scale and/or a defect in the grating can be reduced by simple computing.

Abstract: An optical encoder includes a first signal diode that emits light at an infrared wavelength, and a second signal diode that emits a light at a visible blue wavelength. The optical encoder further includes a first sensor diode having an optical wavelength filter for filtering out light having a wavelength outside the infrared wavelength, and a second sensor diode having an optical wavelength filter for filtering out light having a wavelength outside the visible blue wavelength spectrum. A slotted wheel defining a plurality of radially extending slots rotates past the signal diodes and the sensor diodes such that the sensor diodes may sense the light passing through the slots in the slotted wheel.

Abstract: A rotary position sensor includes a rotatable disk, a first light sensor configured to generate a first opacity signal, a second light sensor configured to generate a second opacity signal, and a comparator. The opacity of the rotatable disk is substantially unique at each radial angle value. The comparator is configured to generate a disk position signal as a function of the first opacity signal and the second opacity signal.

Abstract: Provided are a centrifugal force based platform formed to be rotatable and including a home mark having a retro-reflective property of light, and a centrifugal force based microfluidic system including the platform. The method of determining a home position of the centrifugal force based platform includes: rotating the platform formed and including a home mark having a retro-reflective property of light; emitting light from a light-emitting unit to the platform; and detecting the emitted light, which is retro-reflected by the home mark, in a light-receiving unit, and then determining the home position of the platform based on the detected light.

Abstract: An encoder is capable of being used to compensate for the tilting of a movable object in an apparatus. The encoder includes a fixed scale, and a movable scale integrated with an object that moves during an operation of the apparatus and having a plurality of patterns that are out of phase from each other with respect to the direction of movement of the object. The encoder may be employed by a hard disk drive (HDD) and a servo track recording apparatus. The movable scale is integrated with an actuator arm of the HDD for positioning a read/write head of the HDD, and the fixed scale is fixed to the housing of the HDD. The servo track recording apparatus can use the encoder to record servo track information precisely on a disk.

Abstract: An optical encoder comprises an encoder head and a scale having a second grating that has an optical pattern. The encoder head has a light emission unit to emit specific light to the scale, a light transmission member to transmit the light emitted from the light emission unit and a light detection unit having light detection elements arranged at a predetermined pitch. The light transmission member has a first grating having an optical pattern of a predetermined pitch and an aperture to narrow the light emitted from the light emission unit and impinging on the second grating of the scale. A motion of an image on the light detection elements of the light detection unit is detected. The image is formed by the light reflected or diffracted by the second grating of the scale after the light impinges on the scale through the light transmission member.

Abstract: An absolute position length measurement type encoder includes: a scale in which an ABS pattern based on a pseudorandom code is provided; a light-receiving element for receiving bright and dark patterns formed by the scale; and a signal processing circuit for processing signals subjected to output of the light-receiving element and measuring an absolute position of the scale to the light-receiving element, wherein the signal processing circuit includes a space-dividing number conversion circuit that obtains finer intervals D than the array interval PPDA of the ABS light-receiving element array of the light-receiving element, and simultaneously obtains and outputs a digital value for each of the intervals D subjected to output of the ABS light-receiving element array.

Abstract: A scanning unit, by which a scale, which is movable in relation to the scanning unit in a measuring direction, can be optically scanned. The scanning unit including a detector arrangement and a transparent support having a first surface and a second surface, wherein the detector arrangement is arranged on the second surface. The scanning unit further including a transparent cover plate, which is fastened on the first surface of the transparent support and includes a shielding device for shielding the detector arrangement against electromagnetic fields.

Abstract: A rotary encoder 100 includes a scale 201 that includes a spiral pattern 501 and a radial pattern 502 to be rotatable around a rotation axis, a first sensor unit 301 that detects a light transmitted through the spiral pattern 501 to output a first detection signal, a second sensor unit 302 that detects a light transmitted through the radial pattern 502 to output a second detection signal, and a signal processing circuit 401 that generates an eccentricity correction signal based on the first detection signal to correct the second detection signal based on the eccentricity correction signal. The spiral pattern 501 detects a rotational angular displacement larger than a predetermined value, and the radial pattern 502 detects a rotational angular displacement smaller than the rotational angular displacement detected by the spiral pattern 501.

Abstract: Disclosed herein are a number of different embodiments of reflective multi-turn optical encoders with different light sensing systems. Three different basic configurations of reflective multi-turn optical encoder light sensing systems are disclosed herein: (a) optical encoders employing multiple arrays of light detectors; (b) optical encoders employing multiple arrays of stacked die light sensors, and (c) optical encoders employing variable tone density light sensing systems.

Abstract: A system and method for monitoring the rotation of a generator rotor and calculating a power angle using an optical rotor displacement monitor. The monitor uses a light beam directed toward the rotor to detect a marking thereon, and generates an electrical pulse when the marking is detected. The time between the pulse and a reference point (such as a zero crossing) of the signal waveform from the terminals of the generator is used to calculate the power angle of the generator. The system is adaptive in that it can account for new markings on the rotor. The system may be connected to a network so that power angles from various generators on the electrical network may be compared. The system may further be connected to a common time source such that a time stamp may be applied to the power angles from various generators, allowing for more accurate comparison of the power angles.

Abstract: An optical encoder and method for measuring displacement information using an optical encoder uses an encoder member with multiple digital diffractive optic regions to optically diffract an incident beam of light to produce output beams of light having intensity distribution patterns, which are used to generate electrical signals that provide relative displacement information of the encoder member.

Abstract: A motor may be configured to drive a drive shaft and an engagement member supported on the drive shaft. A detectable feature comprising a rotary member may be supported on the drive shaft such that movement of the drive shaft by the motor changes a state of the detectable feature. At least one sensor may be arranged to detect the state of the detectable feature. Circuitry may be configured to provide a signal in response to a change in the state of the detectable feature detected by the at least one sensor.

Abstract: The invention relates to optical encoders providing binary logic signals representing increments of relative position of two elements of the encoder, the two elements being mobile with respect to one another. The encoder includes at least one pair formed of a luminous emitter and of a luminous detector which are secured to the fixed element, the emitter producing a luminous radiation that the detector can detect, and at least one mark secured to the movable element, during the motion of the movable element with respect to the fixed element, the mark being able to place itself in the path of the luminous radiation so as to be detected by the detector. The encoder further includes a plane printed circuit, secured to the fixed element and on which the pair of emitter and detector is arranged.

Abstract: The present invention relates to a photoelectric encoder including a scale having a grating (incremental pattern) of a predetermined pitch formed thereon and a light source (light-emitting element) and a light-receiving unit, which are relatively displaceable with respect to the scale, wherein light-receiving elements of the light-receiving unit output bright and dark signals of “N” phases, and the phases are detected by fitting a sinusoidal wave function having a fixed period to the bright and dark signals of “N” phases, thereby reducing a position detection error resulting from stains on the scale and/or defects of the grating.

Abstract: An absolute position length measurement type encoder includes: a scale in which an ABS pattern based on a pseudorandom code is provided; a light-receiving element for receiving bright and dark patterns formed by the scale; and a signal processing circuit for processing signals subjected to output of the light-receiving element and measuring an absolute position of the scale to the light-receiving element, wherein the signal processing circuit includes a space-dividing number conversion circuit that obtains finer intervals D than the array interval PPDA of the ABS light-receiving element array of the light-receiving element, and simultaneously obtains and outputs a digital value for each of the intervals D subjected to output of the ABS light-receiving element array.

Abstract: A rotary encoder 100 includes a scale portion 201 in which a first slit array 202 having slits, the number of which is 51, and a second slit array 203 having slits, the number of which is S2, are formed concentrically with respect to a center point 220, and a sensor unit portion 302,304 including a first sensor 311,313 that detects a signal from the first slit array in a first read region 211,215 and a second sensor 312,314 that detects a signal from the second slit array in a second read region 212,216. The rotary encoder meets R1min/R2max?S1/S2?R1max/R2min, where R1max and R1min are respectively the maximum and minimum values of a distance from the center point in the first read region and R2max and R2min are respectively the maximum and minimum values of a distance from the center point in the second read region.

Abstract: This optical encoder includes a light emitting section and a plurality of light receiving elements placed so as to be aligned in one direction in an area where a light beam from the light emitting section may reach. A moving object includes a light-ON section, a light-OFF section and an index pattern section. The light receiving element outputs a first light receiving signal when the light-ON section and the light-OFF section of the moving object pass through a predetermined position corresponding to the light receiving element. The light receiving element outputs a second light receiving signal when the index pattern section of the moving object passes through a predetermined position corresponding to the light receiving element.

Abstract: A surface reflection encoder scale is used with a surface reflection encoder for detecting a relative movement amount of a member for making a relative move. The surface reflection encoder scale includes a substrate of the member or a substrate provided on the member and a reflection phase grating provided on the substrate and having asperities for changing a phase of reflected diffracted light on its surface. The asperities of the phase grating are formed of a deposition film of metal silicide and chromium.

Abstract: An optical rotation angle transmitter includes a code disc that has a digital coding and an analog coding. The digital coding has multiple tracks and is configured so as to be secure against error. A current angle interval can be determined from a plurality of possible angle intervals by means of the digital coding, and a precise angle position of the code disc can be determined within the current angle interval by means of the analog coding. Each of the tracks of the digital coding has a light sensor associated with it. Further provided is a method of scanning a code disc of a rotation angle transmitter.

Abstract: A microfluidic device includes a platform having a disc shape, a chamber formed on the platform, and a home position mark formed on the platform. The at least one chamber and the home position mark are arranged at a same distance from a center of the platform. The home position mark has a light transmittance which is different from a light transmittance of the at least one chamber. A microfluidic system includes a light emitting part which emits light; a light receiving part arranged to receive the light emitted by the light emitting part; the microfluidic device arranged between the light emitting part and the light receiving part; an operating part which rotates the microfluidic device; and a control part which compares an intensity of light incident upon the light receiving part with a with a reference value to detect a reference angle of the microfluidic device.

Abstract: A position-measuring device includes a scanning unit and a measuring graduation that is displaceable thereto in at least one measuring direction. The measuring graduation includes two incremental-graduation tracks extending in parallel in the measuring direction, between which a reference-marking track having at least one reference marking at a reference position extends. The scanning unit includes a first scanning device for generating the reference-pulse signal and a second scanning device for generating the incremental signals. To generate the incremental signals, a scanning beam acts at least once upon each incremental graduation in an incremental-signal scanning field.

Abstract: An encoder is capable of being used to compensate for the tilting of a movable object in an apparatus. The encoder includes a fixed scale, and a movable scale integrated with an object that moves during an operation of the apparatus and having a plurality of patterns that are out of phase from each other with respect to the direction of movement of the object. The encoder may be employed by a hard disk drive (HDD) and a servo track recording apparatus. The movable scale is integrated with an actuator arm of the HDD for positioning a read/write head of the HDD, and the fixed scale is fixed to the housing of the HDD. The servo track recording apparatus can use the encoder to record servo track information precisely on a disk.

Abstract: A transceiver having a light source die, a photodetector die and a substrate is disclosed. The substrate has a first well in which the light source die is mounted and a second well in which the photodetector die is mounted. The substrate has a reflective surface which blocks light leaving the light source from reaching the photodetector unless the light is reflected by an object external to the transceiver. The reflecting surface of the second well in the substrate is shaped to concentrate light received from outside the transceiver onto the photodetector, and in one aspect of the invention it comprises a non-imaging optical element. The light source is powered by applying a potential between first and second contacts on the light source die. A signal is generated between first and second contacts on the photodetector die in response to illumination of the photodetector die.

Abstract: A measurement system (220) for measuring a rotational position of a device (214B) includes (i) a measuring assembly (224) having a first measurement subassembly (226) and a second measurement subassembly (228), and (ii) a coupling assembly (230) having a component coupler (232) and a device coupler (234). The second measurement subassembly (228) rotates relative to the first measurement subassembly (226), and the measuring assembly (224) can measure the amount of relative movement between the measurement subassemblies (226) (228) to determine the position of the device (214B). The component coupler (232) is fixedly coupled to the second measurement subassembly (228) so that rotation of the component coupler (232) results in rotation of the second measurement subassembly (228). The device coupler (234) is fixedly coupled to the device (214B).

Abstract: An absolute position length-measurement type encoder includes a scale having an incremental track, an absolute track, and a reference position track. The incremental track has incremental patterns including first light and dark patterns formed at equal intervals in first periods. The absolute track has absolute patterns representing an absolute position. The reference position track has reference position patterns including second light and dark patterns formed at equal intervals in second periods longer than the first periods. A light source emits a measurement light to the scale. A photodetector receives the measurement light reflected at or transmitted through the scale. A signal processing circuit processes the received light signal of the photodetector to detect an absolute position of the scale.

Abstract: A position transducer system is disclosed for a limited rotation motor that includes an illumination source that directs illumination toward an illumination reflector that rotates with a rotor of the limited rotation motor, and a plurality of detector areas adjacent the illumination source for receiving modulated reflected illumination from the illumination reflector.

Abstract: An optical encoder assembly including at least one light source or emitter element, at least one light detector or sensor element, at least one code member including a plurality of code elements arranged along a track extending along a plane with the emitter element and the sensor element positioned on a first side of the plane, and a reflector element positioned on an opposite second side of the plane and including a reflective surface having one or more collimating reflective surface features that reflect light emitted from the emitter element to the code element and on to the sensor element.

Abstract: A method for determining two pseudo-sinusoidal signals in quadrature from a pseudo-sinusoidal signal transmitted by an encoder is provided. The method using a sensor arranged within reading distance of the encoder, which sensor includes at least four sensing elements which are linearly equally distributed. The sensing elements are each capable of delivering a signal Si representative of the signal transmitted by the encoder. The method measuring the signals Si and combining the signals Si in order to form the signals U=(S1?S2)?(S3?S4) and V=(S2?S3), which signals U and V are in quadrature. A system for determining by implementing such a method, as well as a bearing including such a determination system, are provided.

Abstract: An encoder and method for precisely indicating the position of a first member with respect to a second member by utilizing a pattern of machine-sensible elements carried on a track of the first member; the machine-sensible elements being located at successive incremental rotations on the track of the first member and each representing one of the binary values “0” and “1”; and a plurality of “n” sensors, wherein “n” is greater than “3”, carried by the second member at a plurality of spaced locations thereon in proximity to the track of the first member and alignable with the machine-sensible elements of the first member. Each sensor thus senses the binary value of each machine-sensible element with which it is aligned to produce an output corresponding to the binary value of the machine-sensible element with which it is aligned, whereby the outputs of all the sensors constitute a binary code, preferably a Gray code, of “n” bits identifying the position of the first member with respect to the second member.

Abstract: The invention relates to an information carrier (10), having a metal layer (40) with at least one track (14) in which marks (20) are disposed, which can be detected by means of light of a central wavelength (?) which is emitted by a light source (30) and which is incident upon the information carrier (10) at an angle (?i), and from which the position of the information carrier (10) can be derived, wherein the marks (20) are formed by areas (25) which are structured at least by first structures (22) of a lattice period (?) which are disposed on the back side (40b) of the metal layer (40) and/or on the front side (40a) of the metal layer (40), and wherein the lattice period (?) of the first structures (22) satisfies the equation ?=?/(np*?sin(?i)) or ?=?/(np*+sin(?i)), wherein ? is the central wavelength of the used light, ?i is the angle at which the light of the light source (30) is incident upon the information carrier (10) and np* is the effective index of a plasmon mode along the metal layer (40).

Abstract: A scanning unit for an optical position-measuring device includes a semiconductor light source and at least one downstream reflector element that has a defined optical effect on the beams of rays emitted by the semiconductor light source. The optically active surface of the reflector element is arranged in subregions to be reflection-preventive such that no beams of rays are reflected back from the reflector element into the semiconductor light source.

Abstract: In a triple slit optical encoder, a first grating and a third grating are formed on separate members, and values of a first effective width W1 and a first pitch p1 of an optical pattern on the first grating, and a third effective width W3 and a third pitch p3 of an optical pattern on the third grating are set to values such that a periodic signal having the amplitude effective for detection of a relative displacement of a scale is achieved based on periodicity of the self-image, refractive indices of substances of substances and/or spaces interposed in the optical path from a bare LED up to a photodetector, and the thickness of those substances and/or spaces in a direction substantially perpendicular to a plane on which the second grating is formed.

Abstract: A method of measuring one or more motion parameters of a main shaft in a gyratory or cone crusher is disclosed. Signals are directed from a stationary sensor means located apart from the main shaft to one or more signal reflective surfaces situated on a target located on or adjacent to an upper portion of the main shaft. The target rotates and otherwise moves in unison with the movement of the main shaft. From the elapsed time the distances from the sensor the reflective surfaces on the target are determined. Analyzing the distances over time will yield information on the movement of the main shaft.

Abstract: An optical encoder includes a coding element having a track with multiple transparent sections, a light source positioned to output light to the track, and a photodetector array, positioned to detect light that passes through the transparent sections of the track. The photodetectors of the photodetector array have larger width dimensions than the width dimensions of the transparent sections of the track. Resolution of the optical encoder may be adjusted by changing the resolution of the coding element.