Calibration Patents (Class 324/202)
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Patent number: 6552536Abstract: A reference standard and method for inspecting dual-layered coatings. The reference standard has a first layer adherent to a substrate, the first layer has a predetermined thickness that increases in one direction. Adherent to the first layer is a second layer, the second layer has a predetermined thickness that increases in a direction orthogonal with the first layer. The orientation of the first and second layers of the reference standard provides a spectrum of the possible variations of the dual-layered coating.Type: GrantFiled: June 17, 2002Date of Patent: April 22, 2003Assignee: General Electric CompanyInventor: Richard L. Trantow
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Patent number: 6545468Abstract: A method of calibrating the magnetic coils of a magnetically enhanced reactive ion etcher includes taking magnetic field measurements outside of a closed plasma chamber and correlating such measurements to the magnetic field within the chamber. One or more factors are established which when applied to measurements taken externally yield results representative of measurements taken internally.Type: GrantFiled: August 2, 2001Date of Patent: April 8, 2003Assignee: Taiwan Semiconductor Manufacturing Co., LtdInventors: Hui Ming Kuo, Strellson Cheng
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Patent number: 6534985Abstract: An electromagnetic sensing apparatus which has an electromagnetic transmitter, at least one receiver device, at least one calibration device, a switch and a processor. The transmitter generates a transmitter signal. The receiver device is spaced from the transmitter, senses an electromagnetic field proximate thereto and generates a receiver signal. The calibration device senses an electromagnetic field proximate thereto and generates a calibration signal. The calibration device is positioned such that the distance between the transmitter and the receiver device is greater than the distance between the transmitter and the calibration device. The switch is connected between the receiver device and the calibration device. The processor includes a first input for receiving a signal from one of the at least one receiver device and the calibration device and a second input for receiving a signal from the switch and compares the first input and second input and monitors distortions in the transmitter signal.Type: GrantFiled: December 15, 2000Date of Patent: March 18, 2003Assignee: Geosensors Inc.Inventors: John Scott Holladay, III, James Leonard Corbett Lee
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Patent number: 6532791Abstract: The invention relates to a method for increasing the positioning accuracy of an element (13) which is movably arranged relative to a stator (10). At least two sensors (11, 12) are provided in the stator (10), a first sensor (11) and a second sensor (12), which are arranged at a distance (a) from one another in the stator (10), with respect to the movement direction (P) of the movably arranged element (13). The element (13) which is arranged such that it can move relative to the stator (10) is provided with encoders (130) which can move together with the movable element (13) and, when the element (13) carries out a movement relative to the stator (10), firstly produce a sensor signal (S11) in the first sensor (11) and then, as the movement of the element progresses, produce a sensor signal (S12) in the second sensor (12). First of all, in a calibration run, the movable element (13) is moved over the entire possible range of movement.Type: GrantFiled: October 1, 2001Date of Patent: March 18, 2003Assignee: NTI AGInventors: Kuno Schmid, Daniel Ausderau, Marco Hitz, Ronald Rohner
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Patent number: 6528988Abstract: A system and method for programming a Hall effect sensor while the sensor is connected into the circuitry for a given application. The system includes a fixture for receiving the printed circuit board to which the sensor is mounted. A plurality of contacts, such as pogo pins, are arranged to contact the circuit board at desired pads that permit programming of the sensor, reduction of the voltage applied to the overall circuit during programming, and measurement of the sensor and circuit output. The system includes a voltage limiting circuitry that is electrically connected, via appropriate pogo pins, to the circuitry intermediate the subject sensor and potentially damaged circuit components.Type: GrantFiled: December 21, 2001Date of Patent: March 4, 2003Assignee: Rockwell Automation Technologies, Inc.Inventors: Daniel J. Bolda, Steven T. Haensgen, John L. Scheele, Craig Muschinski
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Publication number: 20030034773Abstract: A method of calibrating the magnetic coils of a magnetically enhanced reactive ion etcher includes taking magnetic field measurements outside of a closed plasma chamber and correlating such measurements to the magnetic field within the chamber. One or more factors are established which when applied to measurements taken externally yield results representative of measurements taken internally.Type: ApplicationFiled: August 2, 2001Publication date: February 20, 2003Applicant: Taiwan Semiconductor Manufacturing Co., Ltd.Inventors: Hui Ming Kuo, Strellson Cheng
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Publication number: 20030020462Abstract: The present invention relates to a compliant laminar eddy current sensitivity standard which comprises a sheet of nonconductive, nonmagnetic material having at least one strand of highly conductive metallic material embedded in the sheet and an adhesive layer attached to a surface of the nonconductive, nonmagnetic material to allow the standard to be adhered to a surface of a part to be inspected. A method using the compliant laminar eddy current sensitivity standard is also described.Type: ApplicationFiled: July 30, 2001Publication date: January 30, 2003Inventors: David A. Bryson, Chris Vargas
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Patent number: 6504360Abstract: The present invention relates to a method for checking or determining the installation air slot between an active sensor and an encoder, wherein the maximum size of the air slot (maximum air slot) which still ensures trouble-free operation of the sensor depends on the level of the supply voltage of the sensor at least within a range of said supply voltage, and which is more particularly characterized by the following method steps: reducing the supply voltage of the sensor to at least one value by which the maximum air slot is each time decreased by a desired test measure, and comparing the at least one test measure with a desired difference between the maximum air slot and the existing air slot by sensing a variation of the sensor output signal by the reduction of the supply voltage, as well as evaluating the comparison result by signaling and/or storing. A corresponding device is also described.Type: GrantFiled: April 20, 2001Date of Patent: January 7, 2003Assignees: Continental Teves AG & Co., OGH HDT Industrieplanung GmbHInventors: Peter Lohberg, Klaus Hildebrandt
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Patent number: 6501262Abstract: The invention relates to a method for applying to a carrier a marking serving to measure length, angle cr the like, such as, for example, a magnetic tape (4), by means of which the accuracy of the measurements is improved. In the case of such methods, in one marking step a means for producing a track with markings, for example a writing head (9), is guided over the carrier and, by virtue of the fact that the carrier is acted upon, markings, for example magnetic north and south poles, are applied therein at predetermined positions of the carrier.Type: GrantFiled: December 1, 1999Date of Patent: December 31, 2002Assignee: Schneeberger Holding AGInventors: Hans-Martin Schneeberger, Frederic L. Way
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Patent number: 6498474Abstract: A rotational sensor system for detecting rotational velocity and rotational direction of a rotating member, such as a vehicle axle, including a tone ring mounted to the rotating member. The system includes a pair of active sensors mounted adjacent to the tone ring and spaced from one another, which, when activated, produce an electric signal in response to movements in the tone wheel. A processor receives the electric signals from the sensors and generates a signal indicative of rotational velocity and rotational direction of the rotating member. Also, preferably, an output signal is created that uses square waves with different amplitude levels for the signal highs and lows depending upon the direction of rotation.Type: GrantFiled: June 27, 2001Date of Patent: December 24, 2002Assignee: Kelsey-Hayes CompanyInventor: Jason D. Turner
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Patent number: 6486654Abstract: A method for calibrating magnetic force microscopes (MFM) or scanning Hall probe microscopes (SHPM) is disclosed, wherein an instrument response function IRF is determined for correcting arbitrary raw MFM- or SHPM-images Si. According to one aspect of the invention a sample with an irregular magnetization pattern M over an extended area is provided, a raw MFM- or SHPM-image S is measured, an approximate sample magnetization pattern M0 and therefrom an approximate magnetic stray field distribution H0 are determined and an instrument response function IRF is calculated using the raw MFM- or SHPM-image S and the approximate magnetic stray field distribution H0. Other aspects of the calibration method consist in that the instrument response function IRF is calculated in Fourier space as IRF(k)=S(k)H0(k) and/or that averages or iterative calculations of instrument response functions IRFj (j=1 . . . m) are performed.Type: GrantFiled: May 2, 2000Date of Patent: November 26, 2002Assignee: Triple-O Microscopy GmbHInventors: Hans Josef Hug, Petrus Johannes Antonius Van Schendel
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Method for compensating mechanical stresses in measuring the magnetic field strength by hall sensors
Patent number: 6483301Abstract: A method for compensating mechanical stresses in measuring the magnetic field strength by Hall sensors is disclosed. It is proceeded in a manner that the electric resistance and/or a measuring quantity proportional to the electric resistance of the Hall sensor is determined in at least two different directions, that the mean value of the determined resistances and/or measuring quantities proportional thereto is calculated, and that the current conducted through the Hall sensor is chosen to be proportional to the mean value calculated.Type: GrantFiled: May 1, 2001Date of Patent: November 19, 2002Assignee: Austria Mikro Systeme International AktiengesellschaftInventor: Volker Kempe -
Patent number: 6479986Abstract: A time/analog converter for adjusting the zero point and amplification of the output characteristic of a sensor includes an integrator whose output is connected to the input of a holding member. A reference voltage and the output voltage of the holding member occur at the input of the integrator. A control means actuates switches connecting the integrator to the holding member and applying the reference voltage and the output voltage to the input of the integrator so that the reference voltage is at the integrator input for a first time interval and the holding member output voltage is at the integrator input for a second time interval. The integrator output voltage is applied to the holding member for a third time interval. A controllable pulse shaper is connected to one of the switches and can close it for a required time interval. A related method is also described.Type: GrantFiled: September 22, 2000Date of Patent: November 12, 2002Assignee: ASM Automation Sensorik Messtechnik GmbHInventors: Klaus-Manfred Steinich, Peter Wirth
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Patent number: 6479993Abstract: An apparatus for detecting the presence or absence of foreign matter in a product is provided which includes a reaction signal generating circuit 2 for outputting a reaction signal associated with the product by detecting a change in pattern of distribution of magnetic fluxes when the product P is passed through an alternating magnetic field; a determining circuit 10 for comparing a value of the reaction signal at a predetermined phase point p1 with a threshold value SH to thereby determine the presence or absence of the foreign matter in the product; and a sensitivity adjusting circuit 12A for adjusting a sensitivity of the reaction signal generating circuit 2 so that the value of a first test reaction signal A at the predetermined phase point p1, which is obtained when a product P added with foreign matter of a minimum size to be detected is passed through the alternating magnetic field, attains a desired level relative to the threshold value SH.Type: GrantFiled: June 27, 2000Date of Patent: November 12, 2002Assignee: Ishida Co., Ltd.Inventor: Harunori Tokutsu
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Patent number: 6476605Abstract: Inductive sensor for non-contact detection of discontinuities of a conductive or ferromagnetic target for determination of target position, movement and speed, or generally of a magnetic image, including a plurality of receiving secondary windings associated with each exciting primary winding, configured to obtain electric signals optimized as a function of the discontinuities of the target. The sensor, combined with a suitable electric measuring circuit, allows global analysis of the signals provided by the secondary windings and configuration of a network in accordance with a predefined selection. An adaptive circuit allows auto-calibration of the sensor.Type: GrantFiled: March 13, 2000Date of Patent: November 5, 2002Assignee: CSEM Centre Suisse d'Electronique et de Microtechnique SAInventor: Yves de Coulon
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Patent number: 6472777Abstract: In a stage assembly, for instance a fine stage using a pair of push-pull electro-magnetic actuators to move the stage back and forth along an axis, there is typically a sensor to determine the actual stage location. This sensor's home position must correspond to the actual stage position where the two opposed actuators are observed to exert forces of the same magnitude but opposing directions on this stage. Since the actuators depend on the sensor reading to exert their forces correctly, misalignment of the home position will decrease system performance. The calibration of this sensor is accomplished using actual system feedback signals, which are the currents drawn by the two opposed actuators, during run time conditions. The sensor is considered calibrated (meaning a virtual “null” position) when each of the two opposed actuators draws the same amount of current. If this is not the case a feedback process calibrates the sensor.Type: GrantFiled: March 14, 2000Date of Patent: October 29, 2002Assignee: Nikon CorporationInventors: Ting-Chien Teng, Bausan Yuan
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Fluxgate magnetic field sensor incorporating ferromagnetic test material into its magnetic circuitry
Patent number: 6456069Abstract: A magnetic field sensor, for sensing the transverse component of the magnetic field intensity H, is based on fluxgate magnetometric principles and includes an “E”-shaped magnetic core. A drive winding is wound about the medial leg of the “E” shape. A sense winding is wound about the base of the “E” shape at the two locations between the medial leg and the extreme legs. A calibration winding is wound about each leg. Another magnetic field sensor, for sensing the normal component of the magnetic induction B, is also based on fluxgate magnetometric principles and includes a magnetic core having a sort of coaxial double cylindrical configuration wherein a basket-shaped cylinder encloses a smaller, solid cylinder. A drive winding, then a sense winding, then a calibration winding are wound over the solid cylinder.Type: GrantFiled: March 2, 2000Date of Patent: September 24, 2002Assignee: The United States of America as represented by the Secretary of the NavyInventors: John F. Scarzello, John J. Holmes, Edward C. O'Keefe -
Patent number: 6452380Abstract: A calibration rod (1) with grooved track (2) and a testing apparatus (17) for magnetic rolls that produces an accurate homing location and probe-to-probe reference for repeated test verification at many testing locations. The grooved track calibration rod can be transported to different equipment to verify that equipment is performing similarly, has improved accuracy, has temperature compensation, uses a circumferential drive movement from one end of a roll magnet and verifies angular position from the other end, eliminates the possibility of angular inaccuracy from twisting of the part being measured during clamping and provides for improved accuracy of several degrees. A high order polynomial curve fit of the data is used to determine the true value of the Gauss level being measured during 360 degree revolution. The apparatus takes measurements to accurately measure magnetic differences which define differences in probe operation.Type: GrantFiled: March 23, 2000Date of Patent: September 17, 2002Assignee: Lexmark International, Inc.Inventors: Wayne Gerard Fieseler, Mark Duane Foster, Robert Edward Hackett, Calvin Dale Murphy, James Edward Nichols
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Patent number: 6445178Abstract: A magnetic level sensor is adapted for interconnecting with a vertically moving component of a vehicle such that the level sensor determines a vertical orientation of the component of the vehicle relative to the frame or chassis of the vehicle. The magnetic level sensor includes a magnetic angular measurement device interconnected to the component of the vehicle such that vertical movement of the component causes a corresponding relative rotational movement of a magnetic element associated with the angular measurement device. An electronic control is included for analyzing an output of the angular measurement device and determining an angle of rotation of the magnetic element and thus a vertical movement of the component. The control further determines an error or offset in the output of the angular measurement device and adjusts an output of the control in response to the error or offset.Type: GrantFiled: February 23, 2000Date of Patent: September 3, 2002Assignee: Donnelly CorporationInventor: Eric J. Hoekstra
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Patent number: 6433541Abstract: Disclosed is a method of obtaining information in-situ regarding a film of a sample using an eddy probe during a process for removing the film. The eddy probe has at least one sensing coil. An AC voltage is applied to the sensing coil(s) of the eddy probe. One or more first signals are measured in the sensing coil(s) of the eddy probe when the sensing coil(s) are positioned proximate the film of the sample. One or more second signals are measured in the sensing coil(s) of the eddy probe when the sensing coil(s) are positioned proximate to a reference material having a fixed composition and/or distance from the sensing coil. The first signals are calibrated based on the second signals so that undesired gain and/or phase changes within the first signals are corrected. A property value of the film is determined based on the calibrated first signals. An apparatus for performing the above described method is also disclosed.Type: GrantFiled: August 7, 2000Date of Patent: August 13, 2002Assignee: KLA-Tencor CorporationInventors: Kurt R. Lehman, Shing M. Lee, Walter Halmer Johnson, III, John Fielden
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Patent number: 6429646Abstract: The invention relates to a method for calibrating the initial sensitivity of the eddy current roll-flaw detecting apparatus and an eddy current roll-flaw detecting apparatus which can be calibrated by the method. The method comprises the following steps: a) detecting an artificial defect sample to obtain a first vector; b) generating an analogue artificial defect signal; c) adjusting the analogue artificial defect signal to make it equal the first vector; and d) inputting the analogue artificial defect signal into the eddy current roll-flaw detecting apparatus, and adjusting the eddy current roll-flaw detecting apparatus to enable it to give a warning, wherein steps a) and c) are both implemented by means of the impedance analyzing unit having the function of displaying the impedance vector built in the eddy current roll-flaw detecting apparatus.Type: GrantFiled: April 6, 2000Date of Patent: August 6, 2002Assignee: Baoshan Iron and Steel CorporationInventor: Shiquan Han
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Patent number: 6424145Abstract: An omega-shaped core is wrapped with two coils arranged to be responsive to magnetic permeable metal and conductive metal objects. The omega core allows the proximity sensor to operate as a saturated core sensor, a variable reluctance sensor or an eddy current loss sensor. The core is made from a thin, highly permeable metal that is preferably formed from a single piece of sheet metal, and comprises a substantially flat, rectangular member bent in four locations to form a head portion, two legs, and two feet. The bends form right angles so that the head portion is perpendicular to the two legs, and the two legs are perpendicular to the two feet. The two feet are parallel to each other and also parallel to the head portion. The core is positioned in a housing with two inductive coils, each coil being positioned around a leg portion of the core. A calibration bolt can be placed through the center of the core to change the level of inductance measured from the two inductive coils.Type: GrantFiled: February 29, 2000Date of Patent: July 23, 2002Assignee: Eldec CorporationInventors: Kevin Woolsey, Jeff Lamping, John Marler, Bernie Burreson, Steve Knudson
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Publication number: 20020092338Abstract: A device for calibrating drag test drives comprises a disk drive unit, a non conductive, non magnetic disk, and a magnet placed substantially planar to the non magnetic disk wherein the disk can spin in the disk drive through a magnetic field produced by the magnet. The device also comprises a current measuring device wherein the device measures the amount of current the disk drive motor draws while spinning the disk.Type: ApplicationFiled: January 15, 2001Publication date: July 18, 2002Inventors: Michael V. Andersen, S. Dennis Evans, Michael J. Scoresby, Wayne A. Sumner, Charles Hudson
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Publication number: 20020093332Abstract: A circuit and method of providing desired response from magnetic field sensors to a predetermined magnetic function. Typically, magnetic field sensors, such as magnetoresistive devices and Hall effect sensors, provide an output which is a characteristic function of the magnetic field density, and so they do not generate a linear response in relation to any predetermined magnetic function, such as is required within numerous position or angle resolving circuits. The present invention utilizes two or more magnetically sensitive devices to tailor the overall sensor output signal to any desired function of the magnetic field density. The devices are connected in such a way that they mutually effect each other's voltages or currents to render the final desired output characteristic.Type: ApplicationFiled: January 18, 2001Publication date: July 18, 2002Inventors: Thaddeus Schroeder, Dale Lee Partin, Joseph Pierre Heremans
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Publication number: 20020084780Abstract: A system and method for programming a Hall effect sensor while the sensor is connected into the circuitry for a given application. The system includes a fixture for receiving the printed circuit board to which the sensor is mounted. A plurality of contacts, such as pogo pins, are arranged to contact the circuit board at desired pads that permit programming of the sensor, reduction of the voltage applied to the overall circuit during programming, and measurement of the sensor and circuit output. The system includes a voltage limiting circuitry that is electrically connected, via appropriate pogo pins, to the circuitry intermediate the subject sensor and potentially damaged circuit components.Type: ApplicationFiled: December 21, 2001Publication date: July 4, 2002Inventors: Daniel J. Bolda, Steven T. Haensgen, John L. Sheele, Craig Muschinski
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Patent number: 6414480Abstract: Calibration of an eddy current inspection system having an eddy current probe and a rotatable turntable is accomplished using a circular calibration standard having a notch of known dimensions formed therein. The calibration standard is mounted on the turntable for rotation therewith. The eddy current probe is positioned adjacent to the calibration standard, and the calibration standard is then rotated so that the probe scans the notch. By providing a rotating scan of the calibration standard, higher scan speeds and more accurate calibrations are achieved.Type: GrantFiled: August 22, 2000Date of Patent: July 2, 2002Assignee: General Electric CompanyInventor: Joseph Anthony Traxler
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Patent number: 6414481Abstract: An apparatus is provided for testing and calibrating a sensor of a complex machine tool while the sensor is completely separated from the machine tool. The sensor, which is typically a gear tooth sensor, can typically comprise a sensing head and a printed circuit board which contains an electronic circuit designed to manipulate signals received from the sensing head. A movable target, such as a gear tooth wheel, is driven by an air motor, and the sensing head is attached to a support structure with the operative surface of the sensing head being located a preselected distance from the discontinuities of the target simulator. A signal receiver, such as oscilloscope is easily connected in signal communication with the printed circuit board so that an operator can adjust the amplitude and offset of the signals as the target simulator is operated.Type: GrantFiled: September 27, 2000Date of Patent: July 2, 2002Assignee: Brunswick CorporationInventor: Michael J. Butzen
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Patent number: 6411102Abstract: The design of an electro-magnetic radiation suppression shield and cooling housing for a computer, server or other electronic device having a computer processor may be greatly enhanced and expedited by a test apparatus that permits the placement of electro-magnetic radiation suppression plates at differing locations, spacings and alignments, which allows a variance in positioning the electro-magnetic radiation source. The test apparatus not only has an air flow cooling opening in which an electro-magnetic radiation suppression panel forms cooling air flow holes but also a fixture for disposing a second similar electromagnetic radiation suppression panel at a distance from the first electro-magnetic radiation suppression panel. Each of the panels may be substituted to test various designs.Type: GrantFiled: January 7, 2000Date of Patent: June 25, 2002Assignee: International Business Machines CorporationInventors: Don Alan Gilliland, Maurice Francis Holahan, James Larry Peacock
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Patent number: 6407546Abstract: A method and system for identifying thicknesses of inspection samples, such as semiconductor wafers is presented. The method and system includes a probe housing, comprising an eddy current sense coil and a linear motion controller, and a computer that controls the linear motion controller and the eddy current sense coil. The computer may be configured to identify a thickness of the inspection sample by a method comprising the generation of a natural intercepting curve based on resistance and reactance measurements of at least two data points. Then, a plurality of corresponding resistance and reactance measurements of a location on the inspection sample is obtained with the eddy current sensor, where the eddy current sensor makes a first measurement at a first distance from the inspection sample, and makes each of the remaining plurality of measurements at a distance that is incrementally further away from the inspection surface.Type: GrantFiled: April 7, 2000Date of Patent: June 18, 2002Inventors: Cuong Duy Le, Anh The Ngo
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Patent number: 6369565Abstract: In a method for determining a thickness of a layer of electromagnetically conductive material, the measurement errors resulting from different quality of the basic material are eliminated. For each basic material, one dimensionless characteristic value (K) is ascertained. With the aid of a characteristic calibration curve, each characteristic value (K) can be assigned a correction factor (F), with which the measured value of the layer thickness (DM) can be converted into a real value of the layer thickness (D). Different electrical and magnetic properties, dictated by the different quality of the basic material, can thus be largely eliminated.Type: GrantFiled: April 28, 2000Date of Patent: April 9, 2002Assignee: Robert Bosch GmbHInventors: Klaus Dobler, Hansjoerg Hachtel, Reinhard Dimke, Franz Auf Der Heide, Richard Blattert, Josef Weber
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Patent number: 6356069Abstract: A calibration standard for calibrating an eddy current inspection probe sized and shaped to inspect a preselected non-planar feature of a manufactured part. The feature extends in a longitudinal direction and in a lateral direction. Further, the feature has an end profile as viewed in the longitudinal direction having a substantially invariant shape and orientation. The calibration standard includes a body having a non-planar surface extending in a longitudinal direction and in a lateral direction. The standard also has an end profile as viewed in the longitudinal direction of the surface substantially identical to the profile of the feature. The surface of the body has an elongate narrow opening extending into the body substantially normal to the surface and traversing the surface of the body at a substantially constant angle with respect to the longitudinal direction of the surface as viewed normal to the surface.Type: GrantFiled: December 2, 1999Date of Patent: March 12, 2002Assignee: General Electric CompanyInventors: Richard L. Trantow, Francis H. Little, Gigi O. Gambrell, John W. Ertel
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Patent number: 6351116Abstract: A system and method for programming a Hall effect sensor while the sensor is connected into the circuitry for a given application. The system includes a fixture for receiving the printed circuit board to which the sensor is mounted. A plurality of contacts, such as pogo pins, are arranged to contact the circuit board at desired pads that permit programming of the sensor, reduction of the voltage applied to the overall circuit during programming, and measurement of the sensor and circuit output. The system includes a voltage limiting circuitry that is electrically connected, via appropriate pogo pins, to the circuitry intermediate the subject sensor and potentially damaged circuit components.Type: GrantFiled: September 30, 1999Date of Patent: February 26, 2002Assignee: Rockwell Automation Technologies, Inc.Inventors: Daniel J. Bolda, Steven T. Haensgen, John L. Scheele, Craig Muschinski
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Patent number: 6336081Abstract: An arrangement for measuring the direction of the geomagnetic field {right arrow over (B)}E, in the proximity of a magnetic jamming device with a magnetic field direction variable as a function of time, which is distinguished by the fact that at least two magnetic field measuring devices are provided, each of which measures all three vector components of the total magnetic field ({right arrow over (B)}1,{right arrow over (B)}2), the magnetic field measuring devices have a position, ({right arrow over (r)}0,{right arrow over (r)}1,{right arrow over (r)}2) which is invariable as a function of time and is fixed relative to one another and relative to the jamming device, and the measured values can be called up synchronously and can be evaluated according to {right arrow over (B)}E=({right arrow over (B)}1+{right arrow over (B)}2)/2+P·({right arrow over (B)}1−{right arrow over (B)}2), P({right arrow over (r)}0,{right arrow over (r)}1,{right arrow over (r)}2) describing the geometricType: GrantFiled: October 8, 1999Date of Patent: January 1, 2002Assignee: Leica Geosystems AGInventors: Silvio Gnepf, Ernst Ramseier
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Patent number: 6335617Abstract: A method for calibrating a magnetic field generator, including fixing one or more magnetic field sensors to a probe in known positions and orientations and selecting one or more known locations in the vicinity of the magnetic field generator. The magnetic field generator is driven so as to generate a magnetic field. The probe is moved in a predetermined, known orientation to each of the one or more locations, and signals are received from the one or more sensors at each of the one or more locations. The signals are processed to measure the amplitude and direction of the magnetic field, at the respective positions of the one or more sensors and to determine calibration factors relating to the amplitude and direction of the magnetic field in the vicinity of the magnetic field generator.Type: GrantFiled: March 8, 1999Date of Patent: January 1, 2002Assignee: Biosense, Inc.Inventors: Daniel Osadchy, Assaf Govari
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Patent number: 6304074Abstract: For the offset calibration of a magnetoresistive angle sensor for the determination of the directions of magnetic fields, the sensor includes a Wheatstone bridge with at least four magnetoresistive resistors. The Wheatstone bridge receives an input signal at its input side, in particular an input voltage, and supplies an angle signal at its output side, in particular an angle voltage, in dependence on the direction of a magnetic field which acts on the Wheatstone bridge. The Wheatstone bridge includes a first and a second pair of mutually opposed, substantially parallel magnetoresistive resistors, the first and the second pair being arranged substantially at right angles to one another, while the direction of the magnetic field can be determined from the angle signal supplied by the Wheatstone bridge by means of an evaluation circuit.Type: GrantFiled: November 10, 1999Date of Patent: October 16, 2001Assignee: U.S. Philips CorporationInventor: Eberhard Waffenschmidt
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Patent number: 6297631Abstract: A magnetic signal reproducing apparatus which can lessen fluctuation of reproduced outputs in reproducing magnetic signals recorded in a magnetic tape by a magneto-resistance effect type magnetic head even if a magnetic tape sliding face of the magneto-resistance effect type magnetic head is abraded. A current value of a sense current when a voltage fluctuation level of the sense current caused when a magnetic field in the normal direction is applied to a magneto-resistance effect element of the magneto-resistance effect type magnetic head is equal with a voltage fluctuation level of the sense current caused when a magnetic field in the opposite direction is applied thereto is set to a predetermined value I0. Then, the current value of the sense current supplied to the magneto-resistance effect element of the magneto-resistance effect type magnetic head is set to be greater than I0 in reproducing the magnetic signals recorded in the magnetic tape.Type: GrantFiled: June 10, 1999Date of Patent: October 2, 2001Assignee: Sony CorporationInventors: Tadashi Ozue, Toshio Shirai, Yoshiteru Kamatani, Tomohiro Ikegami, Takehiko Saito
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Publication number: 20010019264Abstract: A cancellation circuit removes interfering signals from desired signals in electrical systems having antennas or other electromagnetic pickup systems. The cancellation circuit provides amplitude adjustment and phase adjustment to electrical signals induced in an electrical system by received electromagnetic signals. The amplitude-adjusted and phase-adjusted signals are combined to cancel the effects of electromagnetic interference. In an electromagnetic receiver, a plurality of receiver elements provide the cancellation circuit with different proportions of desired and interfering signals to enable removal of the interfering signals. An electromagnetic-wave transmitter having multiple transmitter elements is provided with a cancellation circuit for canceling electromagnetic signals in at least one predetermined region of space.Type: ApplicationFiled: March 29, 2001Publication date: September 6, 2001Inventor: Steven J. Shattil
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Patent number: 6285183Abstract: The present invention provides a method for the direct measurement and quantification of the material volume loss on the surface of a substrate and thus provides an accurate depiction of the surface profile of the surface. The method of the invention comprises inducing eddy currents in a test substrate, measuring the magnitude of the eddy current produced within the substrate at a plurality of locations on the surface of the substrate, and converting the measured eddy current magnitudes at the locations to corresponding volume losses on the test surface using the eddy current magnitude measurements of a reference substrate having defects of predetermined volume loss. Typically, the measurements of the eddy current magnitude on the test surface are converted to actual volume losses by multiplying the measured eddy current magnitude for a sector of the test substrate by the area of the sector and a calibration factor (Cf) representing the volume per unit area eddy current magnitude.Type: GrantFiled: September 29, 1997Date of Patent: September 4, 2001Assignee: McDonnell Douglas CorporationInventors: Michael R. Collingwood, Steven G. Keener
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Patent number: 6281675Abstract: The present specification discloses a preferred method, apparatus, and system for calibrating a magnetic tape system. The magnetic tape system comprises at least one head mounted within a head drum, a magnetic tape that has a data region and a no data region, the magnetic tape being contiguous with the head, and a device for providing a relative motion between the magnetic tape and the head. A preferred embodiment of the present invention has the following. A reference track provided on the magnetic tape. The reference track is located in the no data region, at a constant distance from the data region. A processor programmed to determine the time required for the head to travel from the provided reference track to the data region.Type: GrantFiled: February 16, 1999Date of Patent: August 28, 2001Assignee: Seagate Technology, Inc.Inventor: Turguy Goker
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Patent number: 6279375Abstract: The sensor configuration has a sensor and a calibration circuit, which self-calibrates the system by setting its switching points. The calibration circuit is located in the output circuit of the sensor. The method utilizes the calibration circuit to set an offset in the output circuit using an offset D/A converter in such a way that the switching points coincide with reference values. The offset D/A converter is driven with a calibration logic unit.Type: GrantFiled: October 26, 1998Date of Patent: August 28, 2001Assignee: Siemens AktiengesellschaftInventor: Dieter Draxelmayr
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Patent number: 6275029Abstract: A spacing between a transducer head and disk surface in a disk drive's head-disk interface is monitored. The transducer head includes a magneto resistive element. The surface of the disk includes a region containing at least one asperity extending from the surface to have a height. The transducer head is placed over the region containing the at least one asperity, and the disk is rotated. A determination is then made as to whether the transducer head contacts the at least one asperity.Type: GrantFiled: February 10, 1998Date of Patent: August 14, 2001Assignee: Seagate Technology LLCInventor: Michael D. Schaff
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Patent number: 6265863Abstract: A wheel rotating speed detector for detecting a wheel rotating speed of a motor vehicle, comprising: a magnetism generator provided either at wheel of the motor vehicle or a rotary member integrally rotatable with the wheel; a magnetism detector for detecting magnetism generated by the magnetism generator; a change-over switch enabling the magnetism detector to change over from a normal magnetism detecting mode to a low magnetism detecting mode or vice versa.Type: GrantFiled: April 28, 1998Date of Patent: July 24, 2001Assignee: Pioneer Electronic CorporationInventor: Hitoshi Kaneko
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Patent number: 6265866Abstract: A measuring device for determining the position of a control element, such as a throttle valve in which a temperature-resistant Hal sensor (4) cooperates with a permanent magnet (2), which is connected to the control element by a spindle (3), in order to obviate the need for a conventional mechanical potentiometer. By virtue of the Hall effect, the Hall sensor (4) produces during movement of the control element and thus of the position of the permanent magnet (2) relative to the Hall sensor (4), an output signal (Ua) that is preferably linearly proportional to the movement of the control element. The Hall sensor (4) is programmed to correct temperature, related measurement errors in the permanent magnet.Type: GrantFiled: April 5, 2000Date of Patent: July 24, 2001Assignee: Pierburg AGInventors: Norbert Ludwig, Frank Bürger
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Patent number: 6255815Abstract: A device for measuring and calibrating the strength of magnetic fields is provided. The device includes a coil of wire and either conductive pads or an ammeter/voltmeter attached to the coil of wire. The coil is disposed in the interior of a housing, and a locator window is formed in the housing in a position internal to the coil. The locator window allows the user to see through the device and thus position the device properly with respect to the source of the magnetic field. Preferably, a microprocessor is provided which converts a value of voltage or current induced in the coil into a value of magnetic field strength. The microprocessor transmits the value of magnetic field strength to the display.Type: GrantFiled: August 20, 1998Date of Patent: July 3, 2001Assignee: Neotonus, Inc.Inventor: Kent R. Davey
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Patent number: 6252393Abstract: The invention provides a system and method for normalizing and calibrating a sensor array. The sensor array can comprise differential element sensors, such as for example eddy current sensors, or absolute sensors. A single test specimen is used to normalize and calibrate the sensor array using one or more scans of the test specimen. Notably, only one alignment of the sensor array to the test specimen is required. The test specimen is preferably made of the same or similar type of material as the part to be tested and is of a similar geometric shape that can have a simple flat surface or a more complex surface. A linear feature and several notches are machined into the surface of the specimen by using, for example, electro-discharge machining methods, to provide the necessary signals when scanned by the sensor array. Signals from the linear feature on the test specimen are used to remove any bias and to normalize the dynamic ranges of all of the sensors in the array.Type: GrantFiled: June 10, 1999Date of Patent: June 26, 2001Assignee: General Electric CompanyInventor: Kristina Helena Valborg Hedengren
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Patent number: 6242906Abstract: Methods and systems for calibrating an absolute position encoder where a read head is moved relative to a scale of the absolute position encoder and the absolute position encoder is comprised of a fine scale and a coarse scale. An absolute position of a coarse scale is determined which corresponds to the measurement in a fine wavelength. An ideal coarse absolute position is determined from the fine scale measurements. A deviation between the determined coarse absolute position and the ideal coarse absolute position is then determined. The mean of the maximum positive and negative deviations from the ideal coarse scale absolute position for different intervals of the scale are then stored for the entirety of a measured range. These stored correction values are then used to correct the coarse scale values. The concept can be utilized also in a system with more than two wavelengths, for instance a fine wavelength, a medium wavelength and a coarse wavelength.Type: GrantFiled: May 10, 1999Date of Patent: June 5, 2001Assignee: Mitutoyo CorporationInventor: Nils Ingvar Andermo
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Patent number: 6236200Abstract: A magnetic metal sensor having a high response speed and which can detect small-sized metal pieces and can elongate the separation from the metal pieces. A magnetic metal sensor 2 has a core 22 defining a substantially U-shaped open magnetic path and coils 23, 24 of the same polarity mounted on the core 22. A uniform magnetic field along the direction of magnetic sensitivity is applied by a magnet 25 across the coils 24, 24. If magnetic metal approaches to a open magnetic path portion of the core 22 of the magnetic metal sensor 2, the magnetic reluctance of the magnetic circuit formed by the core and air is changed, as a result of which the impedance of the cores 23, 24 is changed. The magnetic metal sensor 2 detects the possible presence of magnetic metal or its displacement based on impedance changes of the paired coils 23, 24.Type: GrantFiled: May 19, 1998Date of Patent: May 22, 2001Assignee: Sony Precision Technology, Inc.Inventors: Yasuo Nekado, Masaaki Kusumi
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Patent number: 6229306Abstract: The method for measuring magnetic properties of sheet material is able to deliver reliable signals at both low and high magnetic particle density in the sheet material. First a measuring head converts the magnetic properties of the sheet material into electric signals. The electric signals produced by the measuring head are amplified in a certain signal range such that the lower-amplitude electric signals produced by the areas with low magnetic particle density of the sheet material are amplified to a greater extent than the electric higher-amplitude signals produced by the areas with high magnetic particle density of the sheet material. For this purpose the signal range is divided into at least three ranges which are each amplified constantly. The amplification in the two outer ranges is selected equal, and the amplification in the middle range greater than the amplification in the outer ranges.Type: GrantFiled: June 18, 1998Date of Patent: May 8, 2001Assignee: Giesecke & Devrient GmbHInventors: Dieter Stein, Lothar Schütt
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Patent number: 6211662Abstract: A hidden object sensor is described which senses and locates hidden objects hidden behind a surface of an architectural structure. The sensor includes sensing elements for sensing live wires behind the accessible surface, and separate sensing elements for respectively sensing metal and non-metallic objects behind the tested surface. A microprocessor alternates between the use of the various sensing elements and their associated circuits to detect live wires, metal objects, or wood studs. Visible and audible indicators are provided for indicating the device's mode of operation and the locations of sensed hidden objects. If a live wire is sensed, the processor may preclude an indication of a metal object or wood stud.Type: GrantFiled: August 7, 1998Date of Patent: April 3, 2001Assignee: The Stanley WorksInventors: Viresh Bijawat, David L. Wakefield, Russell H. Powers, Ronald Yim
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Patent number: 6208133Abstract: A method and apparatus for calibrating the output signal of a linear position detector without accessing the interior of the detector housing is provided. According to one exemplary embodiment, a magnet is selectively movable toward and away from the exterior of the electronics housing, and a sensor is provided within the housing for sensing the presence of the magnet. According to this embodiment, the linear position detector is calibrated by setting a movable marker at the desired position and pushing the magnet toward the housing. The sensor then detects the presence of the magnet, and a processor saves the position of the marker as a reference point. All future positions of the marker can then be scaled based upon the reference point. Thus, the linear position detector can be calibrated without the need for opening the electronics housing and potentially exposing the electronics components to moisture, contaminants, and/or static electricity.Type: GrantFiled: October 1, 1998Date of Patent: March 27, 2001Assignee: Balluff, Inc.Inventors: Ernst Ehling, Ernst Gass, Andreas Ullrich, Martin Kurz