With Light Beam Indicator Patents (Class 73/653)
  • Patent number: 8950263
    Abstract: The invention concerns a folded pendulum, comprising: a support (F); a test mass (PM); a simple pendulum (SP); an inverted pendulum (IP); the simple pendulum and the inverted pendulum being connected at one of their ends to the test mass (PM) and at the other end to the support (F) by means of 4 corresponding joint systems (G), the test mass being not connected to the support (F) and being therefore free to oscillate, each joint system (G) relevant to the simple pendulum (PS) comprising one or more joints in tension, the folded pendulum being characterized in that: each of the joint systems (G) relevant to the inverted pendulum (IP) comprises one or more joints in compression. The invention further concern a seismic sensor utilizing the folded pendulum according to the invention.
    Type: Grant
    Filed: July 1, 2010
    Date of Patent: February 10, 2015
    Assignee: Universita Degli Studi di Salerno
    Inventors: Gerardo Giordano, Fabrizio Barone
  • Patent number: 8820167
    Abstract: A sensor includes a housing adapted to be secured to a component within a system to be monitored by the sensor, an optical fiber, and a membrane spring assembly. The optical fiber includes a sensing portion containing a fiber Bragg grating that is able to undergo expansion and contraction resulting from movement of the optical fiber at a second location relative to a first location. The membrane spring assembly includes a membrane disc, wherein movement of a central portion thereof causes corresponding displacement of the optical fiber at the second location to cause expansion and contraction of the sensing portion of the optical fiber containing the fiber Bragg grating, which expansion and contraction effects a change in a light wavelength reflected by the fiber Bragg grating. The light wavelength reflected by the fiber Bragg grating can be used to measure movement of the central portion of the membrane disc.
    Type: Grant
    Filed: February 10, 2011
    Date of Patent: September 2, 2014
    Assignee: Siemens Energy, Inc.
    Inventors: Evangelos V. Diatzikis, Michael Twerdochlib, Luis Alberto de Almeida Ferreira, Francisco Manuel Moita Ara├║jo
  • Patent number: 8726732
    Abstract: A device for detecting seismic acceleration includes a proof mass; a base for providing a sensor acceleration, relative to the proof mass, based on the seismic acceleration; and an optical fiber portion operatively connected between the proof mass and the base for providing a fiber tension based on the sensor acceleration. A fiber Fabry-Perot interferometer (FFPI) in the optical fiber portion provides an optical characteristic representative of the fiber tension. A compensator applies a compensating tension to the FFPI to compensate for a change of the optical characteristic due to a temperature change of the FFPI.
    Type: Grant
    Filed: November 17, 2009
    Date of Patent: May 20, 2014
    Assignee: The Australian National University
    Inventors: Ian C. M. Littler, Jong H. Chow, David E. McClelland
  • Patent number: 8604574
    Abstract: The transparent photodetector includes a substrate; a waveguide on the substrate; a displaceable structure that can be displaced with respect to the substrate, the displaceable structure in proximity to the waveguide; and a silicon nanowire array suspended with respect to the substrate and mechanically linked to the displaceable structure, the silicon nanowire array comprising a plurality of silicon nanowires having piezoresistance. In operation, a light source propagating through the waveguide results in an optical force on the displaceable structure which further results in a strain on the nanowires to cause a change in electrical resistance of the nanowires. The substrate may be a semiconductor on insulator substrate.
    Type: Grant
    Filed: May 3, 2011
    Date of Patent: December 10, 2013
    Assignee: International Business Machines Corporation
    Inventor: Tymon Barwicz
  • Patent number: 8531527
    Abstract: An acoustic-wave sensor (10) is constructed by a membrane (11) adapted to be displaced by an acoustic wave, a first waveguide (16a) for transmitting light therein, an optical coupling part (15) to which the light transmitted through the first waveguide (16a) is adapted to be optically coupled, and a second waveguide (16b) through which the light coupled from the optical coupling part (15) transmits. When the membrane (11) is displaced by its reception of the acoustic wave, at least one of an optical coupling coefficient between the first waveguide (16a) and the optical resonator (15) and an optical coupling coefficient between the second waveguide (16b) and the optical resonator (15) is changed to output a corresponding optical signal.
    Type: Grant
    Filed: August 25, 2008
    Date of Patent: September 10, 2013
    Assignee: Canon Kabushiki Kaisha
    Inventors: Chienliu Chang, Kenichi Nagae
  • Patent number: 8499638
    Abstract: A tri-axis accelerometer for use in seismic surveying is provided. The accelerometer comprises at least three fiber optic accelerometer elements which have respective fiber sensor coils, and which are characteristic in that the fiber sensor coils are coiled about a common coiling axis and at least one of the accelerometer elements is a slant angle accelerometer element. A corresponding method of manufacturing a tri-axis fiber optic accelerometer is also disclosed. A fiber optic tri-axis accelerometer for sensing acceleration in three directions is also provided, which comprises a first, a second, and a third sensor base, each base including a first, a second, and a third fixed element, respectively, and a first, a second, and a third movable element, respectively, each pair of fixed and movable elements carrying a fiber sensing coil.
    Type: Grant
    Filed: March 1, 2011
    Date of Patent: August 6, 2013
    Assignee: Optoplan AS
    Inventor: Roar Furuhaug
  • Publication number: 20120247213
    Abstract: Methods, structures, devices and systems are disclosed for implementing optical seismometers that detect seismic information based on optical interferometry. In one aspect, a device includes a first retroreflector attached to a mass of a seismometer, a second retroreflector attached to a member of a frame of the seismometer, the frame structured to suspend the mass, and optical components attached to the member of the frame and configured with the first and second retroreflectors to form an interferometer, in which a change in position of the mass is identified by detecting by a change in an optical path of a light beam generated by a light energy source transmitted to the interferometer.
    Type: Application
    Filed: April 2, 2012
    Publication date: October 4, 2012
    Inventors: Mark A. Zumberge, Jonathan Berger, Erhard Wielandt
  • Patent number: 7906737
    Abstract: An electronic scale having a measuring sensor (1 . . . 16), a digital signal processing unit (18), a digital display (19) and an inclinometer (40). The inclinometer derives a signal for the tilt of the scale from the difference of at least two signals. The digital signal processing unit (18) is provided with an additional circuit component or program routine that adds the two signals and, by way of this cumulative signal, corrects the vibration-distorted signal of the measuring sensor (1 . . . 16). A plurality of inclinometers enables the simultaneous detection of momentary gravitational acceleration. For example, in an electric bubble level, the gas bubble moves out of place when tilted and the diameter of the gas bubble changes when the gravitational acceleration changes. The scale thus provides an additional signal for correcting the influence of disturbances with minimum complexity.
    Type: Grant
    Filed: June 12, 2009
    Date of Patent: March 15, 2011
    Assignee: Sartorius AG
    Inventors: Gerd Freydank, Winfried Graf, Christian Oldendorf
  • Patent number: 7743661
    Abstract: The present invention relates to an optic seismic MEMS sensor. More specifically, a proof mass is supported by a frame having supporting beams. The proof mass is positioned within the frame and has a hinged attachment to the beams. The proof mass has a sensor gap having a first reflector and a second reflector positioned at opposing ends of the sensor gap. An optical fiber injects light into the sensor gap and light is reflected to determine seismic movement of the proof mass with respect to the frame. Stops are provided for limiting the movement of the proof mass to minimize strain on the attachment of the beams and the proof mass.
    Type: Grant
    Filed: February 12, 2007
    Date of Patent: June 29, 2010
    Assignee: Halliburton Energy Services, Inc.
    Inventors: John W. Berthold, Tiansheng Zhou, Ira Jeffrey Bush, Fred McNair
  • Patent number: 7673517
    Abstract: A sensor and a method for sensing a change in mass of a reflective microbeam in a sensor, the sensor having a reflective layer disposed on a substrate and spaced apart from the reflective microbeam. The microbeam receives amplitude modulated laser energy at a first wavelength and is photothermally excited into resonance at the frequency of amplitude modulation, the reflective microbridge and the reflective layer receive optical energy at a second wavelength and reflect the optical energy toward a receiver. A change in reflectivity of the microbeam at different frequencies is determined. A change in reflectivity indicates a change in resonant frequency of the microbeam. Mass of the microbeam changes when a chemoselective material on the microbeam sorbs a target chemical.
    Type: Grant
    Filed: November 13, 2006
    Date of Patent: March 9, 2010
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Todd H. Stievater, William S Rabinovich, Eric J Houser, Stanley V. Stepnowski, R Andrew McGill
  • Patent number: 7667856
    Abstract: An optical characteristic measuring apparatus of the invention is configured in such a manner that a specular reflection light component in reflection light from an object to be measured is received, and shake of the apparatus is detected based on the amount of the received light. The optical characteristic measuring apparatus having the above arrangement enables to precisely measure an optical characteristic of the object to be measured, without the need of providing a mechanical switch or a like device, and without depending on the shape of the object to be measured.
    Type: Grant
    Filed: September 22, 2008
    Date of Patent: February 23, 2010
    Assignee: Konica Minolta Sensing, Inc.
    Inventors: Tomohiro Fukamizu, Yoshiyuki Nagashima, Katsutoshi Tsurutani, Shinji Shimizu
  • Patent number: 7516659
    Abstract: A sensor having a mass that moves relative to a structure is disclosed. A spring mechanism applies a restoring force to the mass when the mass moves from an equilibrium position with respect to the structure. A first code scale is attached to the mass and viewed by a first imaging system that is fixed with respect to the structure. The first imaging system forms images of the first code scale that are used by a controller to provide an indication of the relative position of the mass with respect to the structure. The mass can be located in a sealed chamber in the structure that has a transparent liquid through which the mass moves. The first imaging can view the first code scale from outside the chamber through a transparent window in the chamber.
    Type: Grant
    Filed: May 11, 2006
    Date of Patent: April 14, 2009
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventor: Muniandy Murelitharan
  • Publication number: 20080289429
    Abstract: The present invention relates to an optic seismic MEMS sensor. More specifically, a proof mass is supported by a frame having supporting beams. The proof mass is positioned within the frame and has a hinged attachment to the beams. The proof mass has a sensor gap having a first reflector and a second reflector positioned at opposing ends of the sensor gap. An optical fiber injects light into the sensor gap and light is reflected to determine seismic movement of the proof mass with respect to the frame. Stops are provided for limiting the movement of the proof mass to minimize strain on the attachment of the beams and the proof mass.
    Type: Application
    Filed: May 22, 2007
    Publication date: November 27, 2008
    Inventor: Tiansheng Zhou
  • Patent number: 7420876
    Abstract: An obstacle sensor includes: a supersonic sensor for detecting an obstacle in a first range, the supersonic sensor including a substrate, a transmission device and a reception device disposed on the substrate; a detection element for detecting the obstacle in a second range; and a case. The reception device includes multiple reception elements. At least a part of the first range of the supersonic sensor is different from the second range of the detection element. The supersonic sensor and the detection element are disposed in the case.
    Type: Grant
    Filed: July 6, 2006
    Date of Patent: September 2, 2008
    Inventor: Makiko Sugiura
  • Patent number: 7302852
    Abstract: A vibration measuring and monitoring system (100) for an object (20) includes a laser unit (11), a laser sensor unit (12), and a processor (15). The laser unit is used for emitting a laser beam (13). The laser sensor unit is used for receiving the laser beam, and the laser sensor detects a light intensity signal of the laser beam. The processor is used for processing the light intensity signal of the laser beam. The object is partially disposed between the laser unit and the laser sensor unit. The laser beam crosses the object and is received by the laser sensor unit. The processor obtains a vibration signal by processing the light intensity signal.
    Type: Grant
    Filed: May 19, 2006
    Date of Patent: December 4, 2007
    Assignee: Hon Hai Precision Industry Co., Ltd.
    Inventor: Yang-Chang Chien
  • Patent number: 7168323
    Abstract: A system for sensing vibration of a machine is provided. A light source directs a beam of light toward a light receiving system adapted to receive at least a portion of the beam of light. A light modulating system modulates the light beam received by the light receiving system so as to correspond to vibration of the machine. A processing system operatively coupled to the light receiving system processes data received from the light receiving system to facilitate determining vibration of the machine.
    Type: Grant
    Filed: September 28, 1999
    Date of Patent: January 30, 2007
    Assignee: Rockwell Automation Technologies, Inc.
    Inventor: Frederick M. Discenzo
  • Patent number: 7021146
    Abstract: The present invention provides an attitude sensing device and method for determining an attitude of a reference axis of a package containing a fiber optic sensor sensor. The attitude sensing device comprises an electro-mechanical attitude sensor for generating an electrical signal indicative of the attitude sensor, and converter logic for converting the electrical signal into a stimulus signal. A local power source is preferably provided for the electro-mechanical attitude sensor in the converter logic. The stimulus signal is such that the fiber optical sensor is responsive to the stimulus signal to cause a variation in at least one predetermined property of an optical signal transmitted through the fiber optic sensor, the attitude of the reference axis being determinable from the variation of the predetermined property.
    Type: Grant
    Filed: January 8, 2003
    Date of Patent: April 4, 2006
    Assignee: QinetiQ Limited
    Inventors: Philip John Nash, Mark Andrew Tanner
  • Patent number: 6918283
    Abstract: An apparatus for demonstrating, investigating and observing Brownian motion and temperature of a medium, such as gas or liquid, uses a small particle which is diamagnetically suspended in the medium. The tiny magnetized particle having a known mass is levitated using a diamagnetic technique, and the displacement of the particle over time is observable, which can be used to determine a temperature of the medium. Optionally, a second particle is suspended in a vacuum but mechanically connected to the same apparatus as the first enclosure with the first particle, thereby allowing observation and measurement of non-Brownian movement of the structure, and allowing more precise observation of Brownian movement effects on the first suspended particle.
    Type: Grant
    Filed: January 12, 2004
    Date of Patent: July 19, 2005
    Assignee: International Business Machines Corporation
    Inventor: Viktors Berstis
  • Patent number: 6895131
    Abstract: The present invention provides a configuration where all optical parts of a monitoring system are contained within a seal and within the generator itself. Non-optical preamplifier functions may also be placed within the seal. In this configuration there is an electrical rather than optical feed-through at the generator wall, which is hermetically sealed, unlike a fiber optic feed-through. The fiber optic light source and detector for each sensor is located in the seal on the generator side of the hermetic electrical feed-through. Electrical power and the sensor's converted electrical vibration signals pass through the electrical feed-through to preamplifier circuitry on the outside of the seal where direct electrical connection is then made to a main chassis unit.
    Type: Grant
    Filed: December 5, 2003
    Date of Patent: May 17, 2005
    Assignee: Siemens Westinghouse Power Corporation
    Inventor: Michael Twerdochlib
  • Publication number: 20040244492
    Abstract: A mass is levitated with respect to a base, at least one of which is comprised of a diamagnetic material, with the levitated mass also having a permanent magnetic property. A second permanent magnet is optionally configured such that it attracts the levitation mass away from the base to overcome gravitational force on the mass, thereby suspending the mass over the surface of the base. The mass is contained in a nonmagnetic, non-shielding and optionally optically-transparent housing so as to limit its excursion within a range of levitation positions. A position measurement means such as a laser interferometer, capacitance detector, or pickup coil is configured to measure positional deviations of the mass in response to incident pressure wave, the output of which being an electronic signal representing the pressure wave.
    Type: Application
    Filed: June 26, 2003
    Publication date: December 9, 2004
    Applicant: International Business Machines Corporation
    Inventor: Viktors Berstis
  • Patent number: 6779402
    Abstract: A system and method for measuring acceleration using a fiber optic accelerometer having a pair of fiber optic coils positioned around a deformable support structure. The support structure possesses a nominally cylindrical shape with the fiber optic coils being wound around opposite ends of the cylindrical support structure from each other. The support structure deforms from its nominally cylindrical shape to a conical shape in response to acceleration along a sensing axis. The changing shape of the support structure causes one of the fiber optic coils to expand while the other of the fiber optic coils contracts. The fiber optic coils are included in an interferometer such that acceleration along the sensing axis produces a phase difference between light signals propagating in the fiber optic coils resulting from their expansion and contraction.
    Type: Grant
    Filed: October 18, 2002
    Date of Patent: August 24, 2004
    Assignee: Northrop Grumman Corporation
    Inventors: Mayer Rud, James Arroyo, Michael J. Tweedy
  • Patent number: 6761528
    Abstract: The invention relates to a steam turbine (3) comprising an optical measuring system (60) for measuring a moving blade vibration. A transmitter (55) produces a light beam (61) which strikes the moving blades (27, 29, 31, 33) and is reflected by these into a receiver (57). By providing that the transmitter (55) is separated from the receiver (56), the invention achieves a measuring angle that actually reduces the scattered light effect of the steam enough to enable reliable optical measurements of the blades vibration. The invention also relates to a method for measuring the vibration of a moving blade (33) in a flow channel (19, 21, 23, 25) of a steam turbine (3).
    Type: Grant
    Filed: October 8, 2002
    Date of Patent: July 13, 2004
    Assignee: Siemens Aktiengesellschaft
    Inventor: Frank Woditschka
  • Publication number: 20040069067
    Abstract: A vibration measuring apparatus (10) inlcudes an accelerometer (12) which is contained within a surface micromachined integrated chip, and signal processing means including a high pass filter (14), a low pass filter (16) and an integrator (18).
    Type: Application
    Filed: August 15, 2003
    Publication date: April 15, 2004
    Inventors: Guiseppe Mancinone, Ian Mawson Howard, Paul Andrew Gould
  • Publication number: 20040060358
    Abstract: A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.
    Type: Application
    Filed: September 30, 2003
    Publication date: April 1, 2004
    Inventor: Panagiotis G. Datskos
  • Patent number: 6642848
    Abstract: This invention is pertaining to multi purpose shock sensor comprising three conductive plates arranged in 3 layers in parallel which make 2 variable capacitors connected in series. Two outer plates are firmly attached to a supporting insulating material and the center plate is located between the 2 outer plates and arranged as movable by resilient element toward either side of the outer plate depending on the direction of the impact felt on the shock sensor causing changes of the capacitance values of the both capacitors. If the 2 capacitors are connected across a voltage source through a resistor, the voltage is charged across the 2 capacitors and their charged values are inversely proportional to their capacitance values. Moving the center plate due to a shock causes changes on both capacitance values, which change voltages across the capacitors, and the changed voltage can be used to activate an object.
    Type: Grant
    Filed: April 15, 2002
    Date of Patent: November 4, 2003
    Inventor: Sang J. Choi
  • Publication number: 20030193668
    Abstract: An elastic-wave monitoring device includes an optical system which is arranged so that a circularly polarized light from a light source is incident to a measured object and a light beam from the measured object passes through a polarizing filter to a photodetector. A detection unit detects periodic fluctuation components of an output signal of the photodetector. In the elastic-wave monitoring device, the polarizing filter is arranged to have a polarization transmission axis directed to one of directions of principal axes of an ellipse formed by intersections of an index ellipsoid of the measured object and a plane perpendicular to an incidence direction of the light beam and passing through an origin of the index ellipsoid.
    Type: Application
    Filed: April 4, 2003
    Publication date: October 16, 2003
    Applicant: FUJITSU LIMITED
    Inventors: Shinichi Wakana, Akinori Miyamoto, Satoru Matsuda
  • Patent number: 6494095
    Abstract: A micro electromechanical switch for detecting acceleration or deceleration includes a rectangular planar mass of, for example, etched silicon suspended on a pair of beams from an anchor located in the same silicon base. Motion in a plane of movement caused by acceleration or deceleration is detected by a pair of photodiodes and a light emitting diode located on opposite sides of the planar mass or shutter so that when the shutter moves the interruption of the light is sensed and thus acceleration or deceleration is indicated.
    Type: Grant
    Filed: March 28, 2000
    Date of Patent: December 17, 2002
    Assignee: OpticNet, Inc.
    Inventor: Lawrence A. Wan
  • Patent number: 6354147
    Abstract: At least one parameter of at least one fluid in a pipe 12 is measured using a spatial array of acoustic pressure sensors 14,16,18 placed at predetermined axial locations x1,x2,x3 along the pipe 12. The pressure sensors 14,16,18 provide acoustic pressure signals P1(t), P2(t), P3(t) on lines 20,22,24 which are provided to signal processing logic 60 which determines the speed of sound amix of the fluid (or mixture) in the pipe 12 using acoustic spatial array signal processing techniques with the direction of propagation of the acoustic signals along the longitudinal axis of the pipe 12. Numerous spatial array processing techniques may be employed to determined the speed of sound amix. The speed of sound amix is provided to logic 48 which calculates the percent composition of the mixture, e.g., water fraction, or any other parameter of the mixture or fluid which is related to the sound speed amix. The logic 60 may also determine the Mach number Mx of the fluid.
    Type: Grant
    Filed: June 25, 1999
    Date of Patent: March 12, 2002
    Assignee: CiDRA Corporation
    Inventors: Daniel L. Gysling, Alan D. Kersey, James D. Paduano
  • Patent number: 6311559
    Abstract: The present invention discloses a vibration measurement method and apparatus using a self-mixing type laser Doppler vibration meter. The vibration measurement method according to the present invention comprises: an inclination value calculation step S3 for calculating an ascending inclination and a descending inclination for each beat wave; and a turning point identification step S4 for identifying the turning point of a vibrating object according to the inclination change along the time axis.
    Type: Grant
    Filed: October 28, 1999
    Date of Patent: November 6, 2001
    Assignee: Suzuki Motor Corporation
    Inventors: Tetsuro Maruyama, Akiyoshi Ohno
  • Patent number: 6276536
    Abstract: A method for measuring the ripeness and the texture of a fruit, the method comprising a step for applying a vibration having sequentially hanging frequencies to a fruit to be measured, a step for measuring the intensity of the vibration applied to the fruit and the intensity of the vibration of the fruit, a step for measuring the weight of the fruit, a step for finding the transfer functional characteristic of the fruit by performing frequency analysis based on the intensity of the vibration applied to the fruit and the intensity of the vibration of the fruit, and computing the secondary resonance frequency f0 (i.e.
    Type: Grant
    Filed: March 3, 2000
    Date of Patent: August 21, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Shoji Terasaki, Naoki Wada
  • Patent number: 6161433
    Abstract: A geophone includes an optical element capable of changing its refractive index and path length in response to acceleration of the geophone. The sensor component comprises a mass mounted on a fulcrum for rotational movement against the force of a biasing member. An optical fiber is stretched between the casing of the sensor and an extension of the mass, such that rotational movement of the mass about the fulcrum varies the tension in the fiber. Varying the tension in the fiber varies the optical path length and index of refraction of the fiber, and these variations may be detected as a seismic signal. A first set of magnets dampens the vibratory movement of the mass, and a second set of magnets reduces the frequency of the movement of the mass.
    Type: Grant
    Filed: October 15, 1999
    Date of Patent: December 19, 2000
    Assignee: Geosensor Corporation
    Inventor: Louis W. Erath
  • Patent number: 6041020
    Abstract: The investigation, development and application of a laser-based ultrasonic inspection system to the problems of evaluating polymer/graphite composite materials has been realized. The use of lasers to generate and detect ultrasonic waveforms in materials provides a means to detect material properties remotely. The study consisted of three main aspects: 1) A confocal Fabry-Perot (CFP) based system has been devolved which uses light reflected from the CFP interferometer to derive the ultrasonic signal. This allows higher frequency components of the detected waveforms to be discerned when compared to a CFP-based system using light transmitted through the CFP interferometer. 2) Thermoelastic and ablative laser generation of acoustic pulses in polymer/graphite composite materials has been investigated. Thermoelastic generation of ultrasound occurs when thermal energy deposited by a pulsed laser creates a localized expansion in the material.
    Type: Grant
    Filed: April 21, 1997
    Date of Patent: March 21, 2000
    Assignee: University of Delaware
    Inventors: James N. Caron, James B. Mehl, Karl V. Steiner
  • Patent number: 5951481
    Abstract: An apparatus and method of non-invasive measurement of a chosen region (4) within a body (2), using the transmission of an ultrasonic pulse and the measurement of back scattered optical radiation which has been modulated by the ultrasonic pulse at the region of interest. There may be two or more ultrasonic transmitters (10, 14) to allow control of the vibration of the ultrasonic pulses at the region (4) of interest.
    Type: Grant
    Filed: September 18, 1997
    Date of Patent: September 14, 1999
    Assignee: Critikon Company, L.L.C.
    Inventor: Peter Dilwyn Evans
  • Patent number: 5926584
    Abstract: The invention concerns a faseroptic load sensor with a support structure and at least one interference structure shaped like a wire, on which at least one optical fiber is displayed. The optical fiber is cleared through a wireshaped interference structure at intervals from the support structure so that a large number of bent spots occur. An additional pressure load on the optical fiber vertical to the support structure then causes changes in the bending radius of each bend spot.
    Type: Grant
    Filed: September 13, 1996
    Date of Patent: July 20, 1999
    Inventors: Friedrich Motzko, Jorg Plamper
  • Patent number: 5886265
    Abstract: An optical vibration sensor includes a built-in blade provided with a system for reflecting light, a system for directing light onto the reflecting system, system for collecting the light reflected by the reflecting system and a system for analyzing the intensity and/or the frequency and/or the phase of the reflected light. The blade forms an integral part of an appropriately cut block.
    Type: Grant
    Filed: February 21, 1997
    Date of Patent: March 23, 1999
    Assignee: GEC Alsthom T & D Balteau
    Inventor: Denis Chatrefou
  • Patent number: 5729075
    Abstract: A resonant beam or cantilever is implemented in single crystal silicon or polysilicon. Adjacent the end of the cantilever is an electrode capable of receiving a variable voltage. The cantilever has a natural mechanical resonant frequency when vibrated, and the varying electrostatic field resulting from the variation of applied voltage to the electrode is used to alter the natural restoring force of the cantilever so that a chosen vibration frequency of the cantilever can be achieved. Such vibrating cantilever can be used as the bases for a voltage control oscillator.
    Type: Grant
    Filed: May 23, 1997
    Date of Patent: March 17, 1998
    Assignee: National Semiconductor Corporation
    Inventor: Robert J. Strain
  • Patent number: 5465624
    Abstract: An apparatus for measuring kinematic errors in power transmission mechanisms with an input shaft and an output shaft. The apparatus comprises a pair of laser doppler velocimeters (LDV's) (16,34). Each generates a laser beam split into two equal-intensity parallel beams which are projected so as to strike a shaft while the shaft rotates. The shaft produces reflected beams having a frequency which is shifted from that of the incident beams, thereby producing returning beams which are heterodyne. A measuring (20,38) channel is in communication with each LDV. An attenuator (24) is in communication with one of the measuring channels (20) for decreasing the amplitude of a signal generated by the measuring channel (20). A summing and integrating amplifier (28) is connected to the attenuator, the amplifier generating a signal indicative of kinematic error in the gear mechanism.
    Type: Grant
    Filed: September 7, 1993
    Date of Patent: November 14, 1995
    Assignee: Ford Motor Company
    Inventors: Alexander S. Tseytlin, Francis J. Brasile
  • Patent number: 5437186
    Abstract: An acceleration sensor for measuring accelerations in at least one direction, the sensor including: a plate-like seismic mass which responds to accelerations, is disposed within a fixed frame and is movably fastened to the frame by at least one web extending between the mass and the frame. A first light waveguide for receiving a light beam from a light source, is disposed on a surface of the seismic mass so that a light beam passing therethrough is deflected as a function of movement of the seismic mass, and a second light waveguide is disposed on a surface of the fixed frame opposite an end of the first light waveguide for coupling the light beam to a detector for detecting deflections of the light beam as a measure of detected acceleration by the sensor. Preferably, the first and second light waveguides comprise planar light conductor paths or strips and the mass, webs and frame are all formed of silicon.
    Type: Grant
    Filed: November 6, 1992
    Date of Patent: August 1, 1995
    Inventor: Guido Tschulena
  • Patent number: 5381695
    Abstract: An apparatus for investigating a sample with ultrasound has a probe head formed by a casing, a transducer element of piezoelectric plastics material, and a source for applying a high frequency pulse to the sample. The source is preferably one end of an optical fibre, which fibre extends to a laser remote from the probe head. The transducer element is connected to the sample by an acoustic coupling medium, e.g. water. Thus, the probe head can be moved relative to the sample, and a compact, but efficient, structure is achieved.
    Type: Grant
    Filed: January 14, 1994
    Date of Patent: January 17, 1995
    Assignee: British Technology Group Ltd.
    Inventors: Peter A. Payne, Richard J. Dewhurst
  • Patent number: 5339289
    Abstract: An optical lever acoustic and ultrasound sensor with increased sensitivity using an optical amplification means to amplify the motion of an incident acoustic wave and convert it to an electric signal for image processing. Three approaches to the optical amplification are disclosed. In the first approach, the vibrating mirror is part of a cantilever that increases the angular deflection of the incident light beam. In the second approach, a second, stationary mirror is positioned approximately parallel to the vibrating mirror surface. The reflected light beam is reflected back onto the vibrating mirror, and picks up a another increment of the acoustic signal with each reflection. In the third approach, the effective moment of the optical lever is increased within a small volume by the use of two stationary mirrors to increase the path length from the vibrating mirror to the position-sensitive detector.
    Type: Grant
    Filed: April 5, 1993
    Date of Patent: August 16, 1994
    Inventor: Jon W. Erickson
  • Patent number: 5317929
    Abstract: An accelerometer or seismometer has a pair of flat spirals of optical fiber and has one or more elastic disks bearing a mass and supported for flexure. Each spiral is fixedly attached to a corresponding disk side so that disk flexure lengthens a spiral on one disk side and shortens a spiral on an oppositely facing disk side, the spirals being connected as legs of a fiber optic interferometer so that the interferometer provides an output corresponding to the flexure. A pair of the disks may be mounted oppositely of a sealed body with a pair of the spirals arranged to minimize the effect of pressure changes on the sensor, and a pair of the spirals may be mounted oppositely of a thermally conducting disk to minimize temperature differences between the spirals. The mass may be centrally mounted on a disk with the disk peripherally supported, or the mass may be distributed around the disk periphery with the disk centrally supported for isolation from mounting strain.
    Type: Grant
    Filed: February 7, 1991
    Date of Patent: June 7, 1994
    Inventors: David A. Brown, Steven L. Garrett, Thomas J. Hofler
  • Patent number: 5249163
    Abstract: An acoustic sensor, suitable for use as an ultrasonic transducer, microphone or hydrophone, uses an optical lever to amplify the motion of the sensor surface and convert it to an electrical signal suitable for image processing. In the acoustic sensor, a beam of light from a laser is directed at an oblique angle onto a reflective surface coupled to a sensor membrane. The reflected light strikes a position-sensitive light detector (PSD) which generates an electrical signal indicative of the position of the spot of light on the PSD. When an incident acoustic wave strikes the sensor membrane, the small movements of the reflective surface result in large motions of the spot of light on the PSD, thereby amplifying the acoustic signal and converting it into an electrical signal. Also disclosed is a multi-element sensor array suitable for linear array or phased array imaging.
    Type: Grant
    Filed: June 8, 1992
    Date of Patent: September 28, 1993
    Inventor: Jon W. Erickson
  • Patent number: 5207766
    Abstract: Vibrations of a body are measured by attaching a vibrating element to the body, directing a beam of electromagnetic energy onto the vibrating element and collecting reflected electromagnetic energy from the vibrating element. The magnitude of the reflected electromagnetic energy is processed to determine vibration and/or temperature of the body. The magnitude of the reflected light is preferably a function of second degree of the position of said vibrating element. Processing said magnitude of reflected electromagnetic energy is preferably done by a Fourier series up to a second harmonic.
    Type: Grant
    Filed: July 31, 1991
    Date of Patent: May 4, 1993
    Assignee: Consiglio Nazionale Delle Ricerche
    Inventors: Giuliano Conforti, Andrea A. Mencaglia, Mario Brenci, Anna G. Mignani
  • Patent number: 5191249
    Abstract: This invention relates to a self-aligning bearing for a precision measurement pendulum, in which, between the pendulum and a housing, there are two magnetic bearings, one each on either side of the pendulum, each of which has a bearing ring magnet. The magnetic bearing on the one side of the pendulum has a pole pivot for magnetic centering, opposite which is the pole pivot of a soft iron core. The magnetic bearing located on the other side of the pendulum has a spacer as a mechanical stop, in which there is a tension wire or band stretched between the pendulum and the housing. The magnetic bearings generate magnetic fields of like or unlike polarity extending in the direction of the pendulum axis of rotation, rotationally symmetrically around the latter, and magnetic fields of unlike polarity extending radially to the pendulum axis of rotation, and radially symmetrical to it. The precision measurement pendulum can be used advantageously in a highly-sensitive bearing for measurement purposes.
    Type: Grant
    Filed: September 9, 1991
    Date of Patent: March 2, 1993
    Assignee: Arnold & Richier Cine Technik, GmbH & Co. Betriebs KG
    Inventors: Erich Rauscher, Hans D. Jacoby, Karel Srb
  • Patent number: 5155548
    Abstract: A mismatched path length fiber optic interferometer is optically coupled to an optical fiber and configured to form an omnidirectional acoustic sensor. A second mismatched path length fiber optic interferometer is optically coupled to the optical fiber and configured as a first gradient sensor. A second fiber optic gradient sensor is also optically coupled to the optical fiber. A detector optically coupled to the omnidirectional acoustic sensor and to the gradient sensors converts optical signals output therefrom to electrical signals indicative of the magnitude and direction of changes in an acoustic field. The omnidirectional acoustic sensor may include a length of optical fiber wrapped around the housing while the gradient sensors are mounted inside the housing. The housing perferably has a volume that is adjustable for controlling the buoyancy thereof. Each gradient sensor preferably comprises a pair of mandrels formed to enclose chambers. Optical fiber coils are formed on the mandrels.
    Type: Grant
    Filed: May 22, 1990
    Date of Patent: October 13, 1992
    Assignee: Litton Systems, Inc.
    Inventors: Bruce A. Danver, Jeffrey D. Lastofka, Michael R. Layton
  • Patent number: 5134882
    Abstract: An accelerometer includes a compliant cylinder supported midway along its length and having equal masses at opposite ends. Two birefringent optical fibers with elliptical cores are wound around the cylinder in opposite senses on opposite sides of the support. Radiation from a source is supplied to one end of both fibers and emerges from the opposite end where it is supplied to respective photodiodes via respective polarizers. Acceleration axially of the cylinder causes extensive strain in one fiber and compressive strain in the other which causes equal and opposite changes in birefringence. A processor subtracts the change in outputs of the photodiodes to provide an acceleration output that is independent of temperature.
    Type: Grant
    Filed: September 19, 1990
    Date of Patent: August 4, 1992
    Assignee: Smiths Industries Public Limited Company
    Inventor: Robert M. Taylor
  • Patent number: 5090254
    Abstract: Force transducers are formed of a beam of polysilicon which is mounted at its ends to a silicon substrate and is encapsulated within a polysilicon shell which defines, with the substrate, a cavity around the resonating beam. The cavity is sealed off from the atmosphere and evacuated to maximize the Q of the resonating beam. The beam is produced by deposition of polysilicon in such a way that, combined with subsequent annealing steps, the beam is in zero or low tensile strain. Resonant excitation of the beam may be accomplished in various ways, including capacitive excitation, and the vibratory motion of the beam may be detected utilizing an implanted resistor which is piezoresistive. Formation of the beam is carried out by depositing the beam on a sacrificial layer and surrounding it in a second sacrificial layer before the encapsulating polysilicon shell is formed. The sacrificial layers are etched out with liquid etchant which passes through channels in the periphery of the shell.
    Type: Grant
    Filed: April 11, 1990
    Date of Patent: February 25, 1992
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Henry Guckel, Jeffry Sniegowski
  • Patent number: 5063781
    Abstract: The sensor comprises a vibrating sheet (1), mechanically connected to the body (5A) to be analyzed, and an optical triangulation recording system for recording the displacements of the movable part of the sheet, in particular the free end (1B) opposite to that which is restrained. The recording system comprises two optical fibers (7, 9) ending in microlenses (10, 12) having optical axes mutually inclined and converging in the movable part (1B) of the sheet.
    Type: Grant
    Filed: August 3, 1989
    Date of Patent: November 12, 1991
    Assignee: Consiglio Nazionale Delle Ricerche
    Inventors: Giuliano Conforti, Andrea A. Mencaglia, Mario Brenci, Anna G. Mignani
  • Patent number: 4922095
    Abstract: A method and apparatus for sensing vibrational disturbance using fiber optic coils conducting circularly polarized light. A circularly polarized light source illuminates each of a sensing fiber optic coil in a disturbance-sensitive environment and a reference fiber optic coil in a constant environment, and light from both coils is analyzed through polarization shuttering to detect the degree of polarization rotation thereby to enable determination of frequency and amplitude of the disturbance.
    Type: Grant
    Filed: May 11, 1989
    Date of Patent: May 1, 1990
    Assignee: Conoco Inc.
    Inventor: John S. Gergely
  • Patent number: 4918303
    Abstract: Apparatus for determining physical parameters of a disturbance using a fiber optic coil and linearly polarized source light. The apparatus directs a linearly polarized source light through the fiber optic coil being effected by a disturbance, and then measures the effect by comparing optically the source light and the light affected by changes in fiber coil index to detect and develop digital data related to frequency and amplitude of the disturbance.
    Type: Grant
    Filed: May 11, 1989
    Date of Patent: April 17, 1990
    Assignee: Conoco Inc.
    Inventor: John S. Gergely