Class / Patent application number | Description | Number of patent applications / Date published |
356499000 | Having wavefront division (e.g., by diffraction) | 33 |
20080285050 | POSITION-MEASURING DEVICE - A position-measuring device includes a light source, a first grating, a second grating and photodetectors, light from the light source, which is split into partial beams of different directions at the first and second grating, being directed via a deflecting element to the detector. The deflecting element for incident partial beams having different directions has different regions, so that all partial beams directed from the deflecting element to the detector are approximately parallel. | 11-20-2008 |
20080304079 | DISPLACEMENT MEASUREMENT SENSOR HEAD AND SYSTEM HAVING MEASUREMENT SUB-BEAMS COMPRISING ZEROTH ORDER AND FIRST ORDER DIFFRACTION COMPONENTS - A sensor head for use with a measurement grating is described. The sensor head comprises: a splitter grating configured to split a light beam into first and second measurement beams; a first retroreflector configured to retroreflect the first and second measurement beams toward the measurement grating; and a second retroreflector configured to retroreflect the first and second measurement beams toward the measurement grating. In one embodiment the second measurement beam is diffracted by the measurement grating to form first and second sub-beams and one of the first and second sub-beams comprises a zeroth order diffraction component and a first order diffraction component. In another embodiment, the first and second sub-beams each comprise a zeroth order diffraction component and a first order diffraction component. | 12-11-2008 |
20090027687 | FIXED-POINT DETECTOR AND DISPLACEMENT-MEASURING APPARATUS - A fixed-point detector is provided. The fixed-point detector includes a plurality of fixed-point detecting patterns, a fixed-point detecting light source, and a plurality of photoelectric conversion elements. The plurality of fixed-point detecting patterns each have a pair of diffraction gratings for diffracting incident light in different directions. The fixed-point detecting light source irradiates the pair of diffraction gratings with light while moving in the measurement-axis direction with respect to the plurality of fixed-point detecting patterns. The plurality of photoelectric conversion elements move together with the fixed-point detecting light source, while receiving light beams diffracted by the respective diffraction gratings of the plurality of fixed-point detecting patterns and converting the diffracted light beams into electric signals. | 01-29-2009 |
20090033946 | DISPLACEMENT MEASURING APPARATUS - Disclosed is a displacement measuring apparatus that includes a composite scale having a magnetic pattern and a diffraction grating each aligned in a direction of measuring axis, and a detector head moving in a direction of measuring axis relative to the composite scale. The detector head has a magnetic detection unit detecting a magnetic field exerted by the magnetic pattern to generate first reproduced signals, a light source irradiating the diffraction grating with light, and an optical detection unit detecting the light diffracted by the diffraction grating to generate second reproduced signals. In composite scale, the magnetic pattern and the diffraction grating are arranged such that a pitch of the first reproduced signals is larger than that of the second reproduced signals. | 02-05-2009 |
20090040529 | DISPLACEMENT-MEASURING OPTICAL SCALE AND OPTICAL ENCODER USING SAME - When a convex lens | 02-12-2009 |
20090141285 | Input device and method for making same - A light guide has a first surface and a second surface with diffractive structures. A slanted facet is provided at one corner of the light guide. The diffractive structures have concentric fringes centered near the slanted facet. Fringes are arranged such that a light beam directed from the first surface at a location P toward the second surface is diffracted by the fringes only if the beam encounters the diffractive structures at a certain direction. The diffracted beam is guided and exits through the slanted surface at an exiting angle, which is correlated to the location P. If the light guide is illuminated in such a way that when an object is present at the first surface, it changes the light intensity of the exiting light beam. By detecting the exiting angle and the change of light intensity, the location of the object can be determined. | 06-04-2009 |
20090279100 | SCALE AND READHEAD - An optical element has a member having features which interact with incident light to produce two or more resultant beams. The configuration of the optical element is such that light which interacts with said features when passing through the member from a first side to produce two or more resultant beams does not interact with said features when returned to another side of the member and/or vice versa. The optical element may be used in a readhead of a scale and readhead apparatus. | 11-12-2009 |
20100020330 | Interferometer Calibration System and Method - A metrology system is provided comprising a diffraction grating mounted on the object, and an interferometer head operable to direct at least one measurement light beam towards the grating at a non-zero angle of incidence. With a single first separation in the second direction between the object and the interferometer head, respective displacement measurements are made at known displacements of the object. From the displacement measurements are generated respective original calibration values, each pertaining to a respective one of the known displacements. With a second separation in the second direction between the object and the interferometer head, a displacement of the object is measured. The measured displacement is corrected using an offset calibration value derived from at least one of the original calibration values and pertaining to at least one offset displacement, offset from the measured displacement. | 01-28-2010 |
20100060899 | DISPLACEMENT MEASUREMENT SYSTEM AND METHOD OF USE - A measurement displacement system and method are described. The measurement displacement system comprises a sensor head configured to transmit input optical beams and to receive measurement beams. The system comprises a transmission grating configured to diffract the input optical beams into sub-beams comprising more than one diffraction order. The transmission grating is adapted move in a direction. The measurement displacement system comprises a reflective element configured to diffract the sub-beams from the transmission grating and to return the sub-beams to the transmission grating. The reflective element is substantially stationary relative to the sensor head and the transmission grating selectively recombines the sub-beams to form the measurement beams and returns the measurement beams to the sensor head. | 03-11-2010 |
20100110445 | SLIT APERTURE FOR DIFFRACTION RANGE FINDING SYSTEM AND METHOD FOR USING THE SLIT APERTURE TO FORM A FOCUSED IMAGE - A method and system for forming a focused image on an image plane of a diffraction range finder with a variable pitch diffraction grating. The system includes the variable pitch diffraction grating and a slit through which diffracted light may traverse after having been diffracted by the diffraction grating, wherein the diffracted light is configured to form a focused image on an image plane of a camera after traversing the slit. The method propagates the diffracted through the slit and onto the image plane of the camera, wherein the diffracted light had been diffracted by the variable pitch diffraction grating. | 05-06-2010 |
20100208271 | ORIGIN DETECTION APPARATUS, DISPLACEMENT MEASUREMENT APPARATUS AND OPTICAL APPARATUS - An apparatus includes a light source, a scale which is configured to have first and second diffraction grating portions which differ from each other in a grating pitch, a light receiving portion configured to receive first and second interference light fluxes generated from interference of a plurality of diffraction light fluxes, at the first and second diffraction grating portions, respectively, a light flux emitted from the light source and have different orders of diffraction, and to output first and second periodic signals based on an intensity of the first and second interference light fluxes, respectively, and a computing unit configured to output, based on the first and second periodic signals a signal representing an origin of displacement of the scale. | 08-19-2010 |
20100284022 | DISPLACEMENT MEASUREMENT SYSTEM AND METHOD THEREOF - A displacement measurement system including a coherent light source, a two-dimensional grating, a photo sensor, and a signal processing apparatus is provided. After the coherent light beam enters the two-dimensional grating, a zero-order light beam and a plurality of first-order diffraction beams are generated. The zero-order light beam interferes with two of the first-order beams in different directions, so that corresponding interference fringes are formed on the photo sensor. Accordingly, when the two-dimensional grating moves, displacements of the two-dimensional grating in the different directions are obtained by calculating phase differences of the interference fringes in the corresponding directions. Besides, when the two-dimensional grating rotates, the rotational angle of the two-dimensional grating is obtained from the corresponding rotational angle of a diffraction pattern of the first-order diffraction beams. | 11-11-2010 |
20110043819 | LASER GAUGE INTERFEROMETER - There is provided a laser gauge interferometer with high measurement precision, which uses laser beam interference, includes: a measurement interferometer which generates a measurement output corresponding to a displacement of a moving member; and a correction interferometer which generates a measurement output corresponding to a change in refractive index of air at a constant reference interval. An arithmetic processing device computes a measurement target displacement amount for which the influence of the change in refractive index of air is corrected. A correction laser beam from the correction interferometer passes through the measurement interferometer and thus travels on the same optical path as an optical path of a correction laser beam from the measurement interferometer to become interference light corresponding to the change in refractive index of air through which a measurement laser beam passes, and then enters the arithmetic processing device. | 02-24-2011 |
20110211198 | LIGHTWAVE INTERFERENCE MEASUREMENT APPARATUS THAT CALCULATES ABSOLUTE DISTANCE USING LIGHTWAVE INTERFERENCE - A lightwave interference measurement apparatus includes a wavelength-variable laser which periodically performs wavelength scanning between first and second reference wavelengths to emit light beam, a wavelength-fixed laser which emits light beam having a third reference wavelength, a light beam splitting element which splits the light beams into reference light beam and light beam under test, a phase detector which detects a phase based on an interference signal of the reference light beam and the light beam under test, and an analyzer which sequentially determines an interference order of the third reference wavelength based on the third reference wavelength, first and second synthetic wavelengths, an integer component of a phase change amount in the wavelength scanning, and interference orders of the first and second synthetic wavelengths, and calculates an absolute distance between the surface under test and the reference surface. | 09-01-2011 |
20110235051 | Device for interferential distance measurement - A device for interferential distance measurement that includes a light source that emits a light beam along a propagation direction and a scanning plate including a splitter that splits the light beam into a measurement beam and a reference beam. The device further including a reflector disposed spaced-apart in a direction of the propagation direction and a detector element. The measurement beam and the reference beam are propagated from the splitter along different optical paths toward the reflector, where a back reflection of the measurement beam and the reference beam occurs at the reflector toward the scanning plate. In addition, at a combining location the measurement beam and the reference beam attain interfering superposition, and wherein the measurement beam and the reference beam interfering at the combining location are detected by the detector element so that the detector element generates a distance signal regarding a distance between the scanning plate and the reflector. | 09-29-2011 |
20110286004 | Optical position measuring instrument - A method an optical position measuring instrument for detecting a relative position of a scanning unit and a scale. The optical position measuring instrument includes a scale and a scanning unit, wherein the scanning unit and the scale are movable with respect to one another along a curved measurement direction. The scanning unit includes a detector unit, and a reflector unit that has a first wave front corrector, a beam direction inverter and a second wave front corrector. the reflector unit is disposed and/or embodied in the scanning unit so that beams first pass through a first combination of the scale and the first wave front corrector, then via the beam direction inverter, a back-reflection of partial beams is effected in a direction of the scale, and the partial beams then pass through a second combination of the scale and the second wave front corrector before the partial beams then arrive at the detector unit, wherein, via the reflector unit, it is ensured that wave front deformations of the partial beams, which result via a first diffraction at the scale, are converted into wave front deformations that compensate for resultant wave front deformations of the partial beams upon a second diffraction at the scale. | 11-24-2011 |
20110310397 | POSITION DETECTION DEVICE - A position detection device in which 2nd-order or higher order diffracted light as well as stray light is suppressed from being generated to improve the S/N ratio of a position detection signal as well as to improve detection accuracy. With a pitch d of a diffraction grating | 12-22-2011 |
20120105862 | Optical Angle-Measuring Device - In an optical angle-measuring device for ascertaining the relative movement between at least one scanning grating and a graduated disk having at least one measuring graduation, the scanning grating is in the form of a linear scanning grating, and the graduated disk includes a first and a second combined radial-circular grating as measuring graduation, and has a mirror. An incident beam of rays is initially split at the scanning grating into two partial beams of rays that then propagate in the direction of the first combined radial-circular grating and are diffracted there, then propagate in the direction of the mirror and are reflected there in the direction of the second combined radial-circular grating, subsequently propagate in the direction of the second combined radial-circular grating and are diffracted there, and then propagate in the direction of the scanning grating, where a superposition of the partial beams of rays results. | 05-03-2012 |
20120162663 | OPTICAL ENCODER READHEAD CONFIGURATION - A device for measuring relative displacement between two members includes a scale grating and an optical encoder readhead comprising a first wavelength light source illuminating the grating. The grating outputs scale light to form a moving periodic intensity pattern at the first wavelength. The readhead comprises a plurality of spatial phase detectors comprising: a periodic spatial filter; a phosphor layer that receives light arising from the first wavelength periodic intensity pattern and outputs second wavelength light, and a photodetector element that receives, and is sensitive to, the second wavelength light. The photodetector element inputs second wavelength light corresponding to a spatially filtered version of the first wavelength periodic intensity pattern and outputs a signal indicative of its spatial phase relative to that spatial phase detector. The spatial filtering may be provided by a mask element, or by a pattern of the phosphor layer and/or the detector element, in various embodiments. | 06-28-2012 |
20120250031 | DISPLACEMENT MEASUREMENT METHOD AND DISPLACEMENT MEASUREMENT DEVICE - A displacement measurement device includes a first diffraction grating that generates first diffraction light of a prescribed order; a second diffraction grating movable relative to the first diffraction grating, the second diffraction grating dividing the zeroth-order light that has passed through the first diffraction grating into zeroth-order light and a second diffraction light of a prescribed order; and a first optical sensor that detects interfering light beams formed by the first diffraction light from the first diffraction grating and the second diffraction light from the second diffraction grating to determine an amount of a displacement of the second diffraction grating relative to the first diffraction grating. | 10-04-2012 |
20120257214 | OPTICAL DISPLACEMENT MEASUREMENT DEVICE - An optical displacement measurement device in which variations in interference light by stray light are suppressed to improve interpolation accuracy and detection accuracy. The surface of diffraction grating | 10-11-2012 |
20120287441 | Displacement Detecting Device - A displacement detecting device includes: a diffraction grating having a relief shape; an irradiation optical system adapted to irradiate two beams onto the diffraction grating as p-polarized light; a reflection optical system adapted to reflect two first diffracted lights generated when the two beams is diffracted by the diffraction grating, and cause the first diffracted lights to be incident again on the diffraction grating as p-polarized light so as to generate two second diffracted lights; an interference optical system adapted to cause the two second diffracted lights to interfere with each other to obtain interference light; a light receiving section adapted to receive the interference light; and a position information detecting section adapted to detect position information of the diffraction grating based on an interference signal. The period of the relief of the diffraction grating is no more than 1.5 times the wavelength of coherent light. | 11-15-2012 |
20130010305 | Method and Apparatus for Measuring Displacement - A technique for measuring displacement involves passing parallel laser light from a laser light source through a first diffraction grating to a semi-transparent semi-reflective mirror. A portion of the laser light is reflected as first reversed light, which passes through the first diffraction grating. The remainder of the parallel laser light proceeds to a total reflection mirror and is reflected as second reversed light that passes through the semi-transparent semi-reflective mirror and the first diffraction grating. The amount of refracted light of a predetermined order that is of the first and second reversed light and that results from the first diffraction grating is detected by a first optical sensor, and the amount of displacement is obtained from the interference band or a signal thereof corresponding to the amount of relative motion in the axial direction of the total reflection mirror with respect to the semi-transparent semi-reflective mirror. | 01-10-2013 |
20130100459 | DETECTOR, IMPRINT APPARATUS, AND ARTICLE MANUFACTURING METHOD - A detector for detecting interfering light of diffracted light components diffracted by marks formed on first and second objects includes: an illumination optical system configured to form an intensity distribution including first and second poles which illuminate a first mark arranged on the first object and a second mark arranged on the second object; and a detection optical system configured to detect interfering light of light components diffracted by the first and second marks illuminated by the illumination optical system. The detection optical system detects interfering light of diffracted light components generated when light of the first pole is radiated on and diffracted by the first and second marks. The detection optical system does not detect diffracted light components generated when light of the second pole is radiated on and diffracted by the first and second marks. | 04-25-2013 |
20130188197 | INTERFEROMETRIC APPARATUS FOR DETECTING 3D POSITION OF A DIFFRACTING OBJECT - A position detecting apparatus includes a light source, which supplies a detecting light; a light-collecting optical system which collects the detecting light onto a diffracted light generating portion provided on the object; a light guiding optical system which guides, to a predetermined position, a diffracted measuring light generated from the diffracted light generating portion by receiving the detecting light and a reference light generated from a reference surface by receiving the detecting light; and a photodetector which is arranged at the predetermined position and which detects interference fringes generated by the diffracted measuring light and the reference light. Three-dimensional positional information of, for example, a mask pattern surface or an exposure surface of a photosensitive substrate can be highly accurately detected by a relatively simple construction. | 07-25-2013 |
20130271773 | DISPLACEMENT MEASUREMENT DEVICE, DISPLACEMENT MEASUREMENT METHOD, AND DISPLACEMENT MEASUREMENT PROGRAM - A displacement measurement device includes a plurality of light receiving elements each of which outputs a signal corresponding to illuminance of interference fringe, the elements being arranged in a range of two periods of the interference fringe and arranged with an interval based on the period of the interference fringe in a movement direction of the interference fringe, a differential processing unit configured to perform differential processing on predetermined combinations of the signals output from the elements to generate four signals, a phase calculation unit configured to calculate a phase of the interference fringe on the basis of the signals output from the elements; and an output signal selection unit configured to select two signals from among the four signals on the basis of the phase of the interference fringe and select a signal of which absolute value is larger from among the two selected signals. | 10-17-2013 |
20140092393 | DISPLACEMENT MEASUREMENT APPARATUS AND DISPLACEMENT MEASUREMENT METHOD - There is provided a displacement measurement apparatus including: a light source; a pair of diffraction gratings that light emitted from the light source enters, the pair of diffraction gratings opposing each other while being relatively movable along an optical axis; a first optical sensor that detects interference light obtained by diffracted light emitted from a diffraction grating device of each of the pair of diffraction gratings; a second optical sensor that detects non-interference light emitted from the pair of diffraction gratings; and a correction unit that corrects a signal obtained by the first optical sensor based on a signal obtained by the second optical sensor. | 04-03-2014 |
20150292913 | DOUBLE PASS INTERFEROMETRIC ENCODER SYSTEM - An encoder head includes one or more components arranged to: i) direct a first incident beam to the diffractive encoder scale at a first incident angle with respect to the encoder scale; ii) receive a first return beam from the encoder scale at a first return angle, the first return angle being different from the first incident angle; iii) redirect the first return beam to the encoder scale as a second incident beam at a second incident angle; and iv) receive a second return beam back from the encoder scale at a second return angle, the second return angle being different from the second incident angle, in which a difference between the first incident angle and second incident angle is less than a difference between the first incident angle and the first return angle and less than a difference between the second incident angle and the second return angle. | 10-15-2015 |
20150354937 | INTERFERENTIAL POSITION-MEASURING DEVICE AND METHOD FOR OPERATING AN INTERFERENTIAL POSITION-MEASURING DEVICE - An interferential position-measuring device determines a position of an object which is disposed to be movable along a measurement direction. A light source is configured to emit a beam which is split into two sub-beams. One of the sub-beams impinges on an optical functional element on the object. The sub-beams are subsequently superimposed and interfered at a superposition location and a resulting signal beam propagates toward an evaluation unit configured to generate a position-dependent measurement signal from the resulting signal beam. A switching element is disposed in the signal path downstream of the superposition location and upstream of a signal-digitizing device. The switching element is configured to define a specific sampling point in time. | 12-10-2015 |
20160011016 | INTERFEROMETRIC ENCODERS USING SPECTRAL ANALYSIS | 01-14-2016 |
20160084643 | INTERFEROMETRIC APPARATUS WITH COMPUTER-GENERATED HOLOGRAM FOR MEASURING NON-SPHERICAL SURFACES - Method and system of interferometrically measuring, in reflection, a non-spherical surface with two diffracted beams (of different diffraction orders) formed by a diffractive element positioned transversely to the axis of a common-path interferometer. The first diffracted beam substantially maintains the wavefront of a beam incident onto the diffractive element, while the second diffracted beam has a wavefront profile corresponding to the profile of the measured surface. The first diffracted beam may be reflected by the surface in a cat's eye configuration, while the second diffracted beam is reflected by the surface in a confocal configuration. The surface being measured can be modified to substantially balance radiant powers of the first and second diffracted beams upon reflection off the surface. | 03-24-2016 |
20160109216 | OPTICAL POSITION MEASURING DEVICE - An optical position-measuring device includes a scanning unit and a material measure that is movable relative thereto in a measuring direction. The scanning unit includes a splitting device and an optoelectronic detector arrangement. The splitting device is configured to separate sub-beams incident thereon as a function of wavelength. The splitting device is configured as an asymmetrical interferometer that includes two interferometer arms having different optical path lengths, within which the sub-beams propagate between splitting and recombination until the recombined sub-beams arrive at the detector arrangement. The optical position-measuring device is configured to generate a plurality of phase-shifted scanning signals indicative of a relative position of the scanning unit and of the material measure, wherein phase relations of the generated phase-shifted scanning signals are wavelength-dependent. | 04-21-2016 |
20160116305 | DISPLACEMENT MEASUREMENT DEVICE AND DISPLACEMENT MEASUREMENT METHOD - A displacement measurement device includes: a light source; a first diffraction grating and a second diffraction grating arranged along a path of light from the light source and movable relative to one another, the first and second diffraction gratings generating diffracted light; an optical sensor that detects interference light produced by interference between −nth order diffracted light generated as a result of the second diffraction grating diffracting +nth order diffracted light from the first diffraction grating and +nth order diffracted light generated as a result of the second diffraction grating diffracting −nth order diffracted light from the first diffraction grating, where n is a natural number greater than or equal to 1; and a calculation unit calculating, according to a signal from the optical sensor, a relative displacement between the first and second diffraction gratings in a direction orthogonal to an optical axis of the first and second diffraction gratings. | 04-28-2016 |