Tuning Fork Patents (Class 73/504.16)
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Patent number: 7000472Abstract: A gyro-vibrator supporting mechanism for supporting a gyro-vibrator via a support section upon a substrate in a vibration unit in which a vibrator is installed, the gyro-vibrator having a drive section to which a Coriolis force is applied upon an angular rotation of the gyro-vibrator with the drive section vibrating in a first direction, the detection section vibrating in a second direction perpendicular to said first direction in response to said Coriolis force and in accordance with the magnitude of said Coriolis force for detecting the strength of the Coriolis force and said gyro-vibrator rotating about an axis in a third direction perpendicular to said first and second directions and including a support section for supporting said drive section and said detection section relative to the substrate, and wherein the supporting mechanism comprises a characteristic resonance frequency of vibration along at least one of the first and the second directions that is lower than a characteristic resonance frequencyType: GrantFiled: May 28, 2004Date of Patent: February 21, 2006Assignee: Seiko Epson CorporationInventor: Yusuke Kinoshita
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Patent number: 6981415Abstract: By applying a first value of voltage to a first side of a MEMS gyroscope and applying a second value of voltage to a second side of the MEMS gyroscope, the start time of the MEMS gyroscope may be improved. The first and second value of voltage may be provided by a bias power source, such as a battery or a super capacitor. The first value of voltage may be substantially equal in magnitude to and opposite in polarity to the second value of voltage. The bias power source may also be applied to drive electronics connected to the MEMS gyroscope. The bias power source may prevent amplifiers within the drive electronics from saturating during the start time.Type: GrantFiled: June 9, 2004Date of Patent: January 3, 2006Assignee: Honeywell International Inc.Inventors: William P. Platt, Mark W. Weber
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Patent number: 6978673Abstract: A method for providing micro-electromechanical systems (MEMS) devices with multiple motor frequencies and uniform motor-sense frequency separation is described. The devices each include at least one proof mass, each proof mass being connected to a substrate by a system of suspensions. The method includes controlling the resonant frequencies of the MEMS device by adjusting at least two of a mass of the proof masses, a bending stiffness of the proof masses, a length of the suspensions, and a width of the suspensions.Type: GrantFiled: February 7, 2003Date of Patent: December 27, 2005Assignee: Honeywell International, Inc.Inventors: Burgess R. Johnson, Max C. Glenn, William P. Platt, David K. Arch, Mark W. Weber
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Patent number: 6972619Abstract: In order that an amplifier with a gain proportional to source voltage is obtained, the drain-source voltages of first and second P-channel MOS-FETs are zero-biased, and a voltage shifted higher by the amount of the threshold voltage of the P-channel MOS-FET on the basis of a voltage obtained by dividing the power source voltage by resistors is applied to the positive input terminal of an operational amplifier. The gate of one of the first and second MOS-FETs is connected to a circuit ground, and a negative fixed voltage with reference to the potential obtained by dividing the power source voltage by resistors is applied to the gate of the other MOS-FET. The ON resistances of the two MOS-FETs are used as the input resistor and the feedback resistor of the operational amplifier, respectively.Type: GrantFiled: December 12, 2003Date of Patent: December 6, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masaharu Sato, Takuma Ishida, Taku Kobayashi
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Patent number: 6955084Abstract: The present invention discloses a gyroscope comprising an isolated resonator including a post proof mass and counterbalancing plate. One or more double beam flexures each interconnect the counterbalancing plate and the proof mass with a first and a second beam attached to the post proof mass and a third and a fourth beam attached to the counterbalancing plate. A baseplate is affixed to the resonator by the double beam flexures. The counterbalancing plate and the proof mass transfer substantially no net momentum to the baseplate when the resonator is excited.Type: GrantFiled: April 10, 2003Date of Patent: October 18, 2005Assignees: The Boeing Company, California Institute of TechnologyInventors: A. Dorian Challoner, Kirill V. Shcheglov
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Patent number: 6940433Abstract: A method of distinguishing an analog drive signal from a pickoff signal for attenuating the effect of electrical cross-coupling between the analog drive signal and the pickoff signal. The method may include receiving a periodic digital signal at a first frequency in the form of a stream of digital data values, randomly inverting at least one of the digital data values and converting the stream of digital data values to a stream of analog data values to form an analog drive signal. The method may also include driving a sensor, physically coupled to a resonant member configured to oscillate at a second frequency, using the analog drive signal and sensing changes in the movement of the resonant member detected by the sensor for producing a pickoff signal.Type: GrantFiled: November 14, 2003Date of Patent: September 6, 2005Assignee: Northrop Grumman CorporationInventors: Daniel A. Tazartes, John G. Mark
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Patent number: 6931927Abstract: A tuning-fork vibration gyro including a ferroelectric tuning-fork vibration body generating a plurality of sensor signals and a sensor circuit to which the sensor signals generated by the tuning-fork vibration body are input. The sensor circuit includes a differential amplifier having two input terminals between which the sensor signals are input, and a capacitor being connected between the two input terminals of the differential amplifier.Type: GrantFiled: July 24, 2003Date of Patent: August 23, 2005Assignee: Fujitsu Media Devices LimitedInventors: Kazuhiro Ohta, Masanori Yachi, Yoshitaka Takahashi, Kazutsugu Kikuchi, Keiji Saito
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Patent number: 6934660Abstract: Due to restrictive tolerancing, structural imperfections that reduce performance of fabricated micro gyroscopes are typical. While feedback control is normally used to compensate for these imperfections, there are limitations to how large of errors for which this strategy can compensate without interfering with the performance of the sensor. A multi stage control architecture comprising in situ self-diagnostic capabilities, electronic “trimming” of errors, and feedback control allows for the compensation of all magnitudes of errors without interfering with the performance of the device. The self-diagnostic capabilities include an algorithm for determining structural imperfections based on the dynamic response of the system. The feedforward portion of the control is used to “trim” large imperfections, while the feedback portion compensates for the remaining non-idealities and small perturbations. A control architecture is shown in a gyroscope using nonlinear electrostatic parallel plate actuation.Type: GrantFiled: February 20, 2003Date of Patent: August 23, 2005Assignee: The Regents of the University of CaliforniaInventors: Christopher C. Painter, Andrei M. Shkel
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Patent number: 6918298Abstract: A horizontal and tuning fork vibratory microgyroscope detects angular velocity and angular acceleration of an inertial object when the inertial object is rotated, wherein resonance directions of the microgyroscope are on the same horizontal plane in both sensing and driving modes. The microgyroscope includes a substrate, an anchored pad unit, an outer elastic element unit, an outer frame, a sensing electrode unit, an inner elastic element unit including a plurality of inner elastic elements connected to the inside of the outer frame, an inner weighted element unit including a pair of first and second inner weighted elements each having a driven comb, and a driven electrode unit including a comb drive forming a comb structure.Type: GrantFiled: July 12, 2004Date of Patent: July 19, 2005Assignee: Samsung Electro-Mechanics Co., Ltd.Inventor: Kyu Yeon Park
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Patent number: 6915694Abstract: The object of the present invention is to provide an angular velocity sensor that uses Coriolis force with a flatly supported double tuning fork structure that uses an in-plane asymmetrical flexural secondary mode. A large support area is used to provide a high-precision angular velocity sensor with superior resistance to vibration and impact. A double tuning fork gyro-sensor is formed integrally from: two arms; a driver electrode formed on the arms; and a double tuning fork supporting the ends of the arms. Also included are: a detection module connected to the double tuning fork support section; a detection electrode formed on the detection module; and a support securing section for the detection module. When there is rotation, the Coriolis force acting on the arms is transferred to the detection module by way of the double tuning fork support section so that an in-plane asymmetrical flexural secondary vibration takes place.Type: GrantFiled: September 17, 2003Date of Patent: July 12, 2005Assignee: Toyo Communication Equipment Co., Ltd.Inventors: Yoshiro Tomikawa, Kenji Sato, Atsushi Ono
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Patent number: 6912901Abstract: The present invention aims to present an angular velocity sensor having a self diagnosis function. An angular velocity sensor of the present invention includes a driving part for stably vibrating a driving part of a sensor element having a driver part and a detector part for detecting an angular velocity and detection means for detecting the angular velocity of the sensor element and obtains a self diagnosis signal for a malfunction by detecting a mechanical coupling signal obtained at the detection means.Type: GrantFiled: July 8, 2003Date of Patent: July 5, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Toshiyuki Nozoe, Takeshi Uemura, Masami Tamura
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Patent number: 6904802Abstract: A vibrating gyroscope includes a tuning fork vibrator having two legs defined by piezoelectric members which are polarized in opposite directions of thickness which are bonded to each other between a first principal surface and a second principal surface, so as to have a tuning fork shape with one fixed end. Two electrodes divided in a width direction of the two electrodes are provided on a first principal surface of the respective two legs and an electrode is provided on a second principal surface of the respective two legs. Among four electrodes provided on the first principal surface of the respective two legs, two electrodes that are disposed inside-to-inside or outside-to-outside are connected together to define a driving electrode, and the remaining two electrodes define a detection electrode and a feedback electrode. All of the electrodes provided on the second principal surfaces of the two legs are connected together, and are connected to a reference voltage or are floating.Type: GrantFiled: July 14, 2004Date of Patent: June 14, 2005Assignee: Murata Manufacturing Co., Ltd.Inventors: Katsumi Fujimoto, Hironari Yamamoto
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Patent number: 6880399Abstract: A vibrator is received within a case and the case is contained in a containing portion. Further, the case is arranged to be supported by the surrounding terminals having first ends thereof embedded in the containing portion. By virtue of the described configuration, the vibrator is securely retained by the case even if strong vibrations are applied to the terminals. With this configuration, an angular velocity sensor ensuring the strength to retain the vibrator even if the vibrator is reduced in size and causing no degradation of the output characteristic even when subjected to strong vibrations can be provided.Type: GrantFiled: July 30, 2003Date of Patent: April 19, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideo Okoshi, Toshiyuki Nozoe, Tomomasa Omawari
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Patent number: 6865945Abstract: An angular velocity sensor, which is able to reduce the variations of driving resonance frequency of the vibrator and to improve the reliability of the sensitivity of detection signal with respect to the angular velocity applied, is provided. The angular velocity sensor comprises a vibrator, and a tuning-fork as the vibrator is formed of a silicone substrate with crystal orientation (100) as its main face, and a side face nearly perpendicular to the driving direction (X direction) of the arm of the tuning-fork corresponds to a crystal orientation where the elastic modulus is less dependent on azimuth angle.Type: GrantFiled: June 5, 2003Date of Patent: March 15, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Michihiko Hayashi, Hirofumi Tajika, Masaya Nakatani
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Patent number: 6862934Abstract: A tuning fork gyroscope typically including at least one proof mass with an upper sense plate disposed above the proof mass and a lower sense plate disposed below the proof mass and means for sensing changes in the nominal gaps between the sense plate and the proof mass and for outputting a signal indicative of the gyroscope angular rate.Type: GrantFiled: October 4, 2002Date of Patent: March 8, 2005Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Marc S. Weinberg, Anthony S. Kourepenis, William D. Sawyer, Jeffrey T. Borenstein, James H. Connelly, Amy E. Duwel, Christopher M. Lento, James R. Cousens
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Patent number: 6860151Abstract: A method for reducing undesired movements of proof masses in micro-electromechanical systems (MEMS) devices is described where the proof masses are suspended above a substrate by one or more suspensions. The method includes providing an anchor on the substrate substantially between a first proof and suspensions for the first proof mass and a second proof mass and suspensions for the second proof mass, coupling a first portion of a beam to the first proof mass, coupling a second portion of the beam to the second proof mass, and attaching a third portion of the beam to the anchor, the third portion extending between the first portion and second portion of the beam, the anchor and the third portion configured to allow for rotation about an axis perpendicular to the substrate.Type: GrantFiled: February 7, 2003Date of Patent: March 1, 2005Assignee: Honeywell International Inc.Inventors: William P. Platt, Burgess R. Johnson
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Patent number: 6837108Abstract: A MEMS gyroscope system and method for increasing a dynamic range of the MEMS gyroscope is provided. By adjusting a scale factor of the MEMS gyroscope, the highest sensed rate will be increased, which increases the dynamic range. The scale factor may be adjusted by using a variable sense bias and/or an automatic gain control loop in sense electronics.Type: GrantFiled: April 23, 2002Date of Patent: January 4, 2005Assignee: Honeywell International Inc.Inventor: William P. Platt
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Patent number: 6834247Abstract: A gyroscope that may include various sources of error, with those sources of error each being dependent upon a different parameter, is associated with a simulation or “model” of the gyroscope which is typically a computer simulation. The computer simulation is provided with errors which can be adjusted to be identical with the errors present in the real gyroscope. An arrangement is provided to adjust the errors in the model of the gyroscope to be identical with the errors in the real gyroscope, that arrangement including Kalman filters which receive signals generated by subtracting the outputs of the real gyroscope and the model gyroscope, while simultaneously varying the various inputs to the real gyroscope. The Kalman filters also generate a signal which is an estimate of the angular rotation being sensed by the real gyroscope.Type: GrantFiled: July 3, 2002Date of Patent: December 21, 2004Assignee: Autoliv Development ABInventors: Nils Hiedenstierna, Gert Andersson, Per Svensson
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Publication number: 20040250621Abstract: A tuning fork vibrator includes a long plate-shaped vibration unit having a first principal surface and a second principal surface, a base disposed at one end of the second principal surface of the vibration unit in the longitudinal direction, and a slit for dividing the vibration unit into two legs defining a tuning fork along the longitudinal direction symmetrically in the width direction of the vibration unit. The slit is formed so as to include a portion of the base in the vicinity to the vibration unit.Type: ApplicationFiled: July 14, 2004Publication date: December 16, 2004Applicant: Murata Manufacturing Co., Ltd.Inventors: Katsumi Fujimoto, Hironari Yamamoto
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Publication number: 20040244484Abstract: A method for providing conductive paths into a hermetically sealed cavity is described. The sealed cavity is formed utilizing a silicon-glass micro-electromechanical structure (MEMS) process and the method includes forming recesses on a glass substrate everywhere that a conductive path is to pass into the cavity, and forming conductive leads in and around the recesses. A glass layer is deposited over the substrate, into the recesses, and over the conductive leads and then planarized to expose portions of the conductive leads. A sealing surface is formed on at least a portion of the glass layer. Silicon is then bonded to the sealing surface of the planarized glass layer, the wafer being configured such that a portion of each lead is within the sealed cavity and a portion of each lead is outside the sealed cavity.Type: ApplicationFiled: July 14, 2004Publication date: December 9, 2004Inventors: Robert D. Horning, Jeffrey A. Ridley
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Patent number: 6817244Abstract: A method for reducing effects of common mode oscillations between two respective proof masses in micro-electromechanical systems (MEMS) devices is described. The MEMS devices also include a motor pickoff comb, a sense plate, and a motor drive comb for each proof mass. The method includes amplifying signals received from respective motor pickoff combs, inverting the amplified signal from one of the motor pickoff combs, and generating a difference signal between the inverted, amplified signal from one pickoff comb, and the non-inverted, amplified signal from the other pickoff comb. The method also includes inputting the difference signal into a control loop and generating motor drive signals for respective motor drive combs with the control loop.Type: GrantFiled: January 6, 2003Date of Patent: November 16, 2004Assignee: Honeywell International Inc.Inventor: William P. Platt
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Patent number: 6810735Abstract: A sensing apparatus comprises a sensing unit and a supporting unit. The sensing unit detects a direction and an amount of physical quantity applied thereto. The sensing unit has a detection reference axis along which the direction and the amount of the physical quantity are detected. The supporting unit stationarily supports the sensing unit. The sensing unit is inclined relative to the supporting unit by a predetermined angle so that a difference in angle between the detection reference axis and the direction of the physical quantity actually applied to the sensing unit when detecting the direction and the amount of the physical quantity is reduced.Type: GrantFiled: February 3, 2003Date of Patent: November 2, 2004Assignee: Pioneer CorporationInventors: Hitoshi Kaneko, Tatsuya Okamoto, Isao Endo
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Patent number: 6806797Abstract: In a tuning-fork piezoelectric resonator element, a quartz wafer is subjected to wet etching such that the lengthwise, widthwise, and thickness directions of resonating arms are oriented corresponding to the Y-axis, X-axis, and Z-axis of quartz crystal, lengthwise grooves are provided on principal surfaces of the resonating arms so that the center lines thereof are placed offset in the -X-direction from the center lines of the resonating arms, thereby balancing the stiffness between the right and left portions in the widthwise direction of the resonating arms, and stabilizing bending of the resonating arms.Type: GrantFiled: March 7, 2003Date of Patent: October 19, 2004Assignee: Seiko Epson CorporationInventor: Masayuki Kikushima
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Patent number: 6799461Abstract: A tuning fork vibrator includes a long plate-shaped vibration unit having a first principal surface and a second principal surface, a base disposed at one end of the second principal surface of the vibration unit in the longitudinal direction, and a slit for dividing the vibration unit into two legs defining a tuning fork along the longitudinal direction symmetrically in the width direction of the vibration unit. The slit is formed so as to include a portion of the base in the vicinity to the vibration unit.Type: GrantFiled: June 4, 2003Date of Patent: October 5, 2004Assignee: Murata Manufacturing Co., Ltd.Inventors: Katsumi Fujimoto, Hironari Yamamoto
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Patent number: 6796177Abstract: A gyroscopic apparatus includes two gyro sensors having substantially the same structure. The two gyro sensors are arranged on first and second major surfaces, respectively, of a mounting base so that the gyro sensors have an approximately 180-degree rotation symmetry about a virtual rotation axis penetrating the mounting base substantially parallel thereto in the same direction as rotation detecting axes. The outputs of the two gyro sensors are added, and the sum is output. Thus, the output of the gyroscopic apparatus is much less susceptible to impact from a specific direction, and a high detection accuracy can be maintained.Type: GrantFiled: March 15, 2002Date of Patent: September 28, 2004Assignee: Murata Manufacturing Co., Ltd.Inventor: Akira Mori
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Patent number: 6792792Abstract: A balanced resonant micro electromechanical system angular rate sensor includes a feedback control loop that generates a null signal to rebalance the sense element to cancel any a Coriolis force induced displacement of the proof mass. The null signal is proportional to the Coriolis force and is used as the sensor output signal. A test signal is injected into the null signal feedback control loop. The resulting sensor output signal is a function of the test signal. If there is no change in the output signal following the injection of the test signal or if the output signal resulting from the test signal exceeds a predetermined threshold, the sensor is defective. Because the test signal is used to cancel the proof mass displacement, the test verifies operation of the sensor element.Type: GrantFiled: May 31, 2002Date of Patent: September 21, 2004Assignee: Kelsey-Hayes CompanyInventor: Michael L. Babala
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Publication number: 20040118206Abstract: A tuning-fork type vibration gyro enables to suppress pyroelectric noise caused by temperature change and to obtain sensor output having high signal-to-noise ratio. The tuning-fork type vibration gyro includes a tuning-fork type vibration body having two arms mutually disposed in parallel and a base for commonly supporting one end of the each arm, wherein a longitudinal direction of the two arms is defined as a z-axis and a perpendicular direction thereto is defined as an x-axis; driving electrodes respectively formed on the two arms for generating vibration of the two arms in a direction parallel to the x-axis; detecting electrodes respectively formed on the two arms for detecting electromotive force generated when the tuning-fork type vibration body is rotated around the z-axis; and dummy electrodes formed on the two arms in respective areas different from the driving electrodes and the detecting electrodes.Type: ApplicationFiled: July 24, 2003Publication date: June 24, 2004Applicant: Fujitsu Media Devices LimitedInventors: Kazuhiro Ohta, Masanori Yachi, Yoshitaka Takahashi, Kazutsugu Kikuchi, Keiji Saito
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Patent number: 6752017Abstract: A yaw-rate sensor is proposed having a first and a second Coriolis element (100, 200) which are arranged side-by-side above a surface (1) of a substrate. The Coriolis elements (100, 200) are induced to oscillate parallel to a first axis. Due to a Coriolis force, the Coriolis elements (100, 200) are deflected in a second axis which is perpendicular to the first axis. The first and second Coriolis elements (100, 200) are coupled by a spring (52) which is designed to be yielding in the first and in the second axis. Thus, the frequencies of the oscillations in the two axes are developed differently for the in-phase and antiphase oscillation.Type: GrantFiled: March 19, 2003Date of Patent: June 22, 2004Assignee: Robert Bosch GmbHInventors: Rainer Willig, Andreas Thomae, Burkhard Kuhlmann, Joerg Hauer, Udo Martin Gomez, Siegbert Goetz, Christian Doering, Michael Fehrenbach, Wolfram Bauer, Udo Bischof, Reinhard Neul, Karsten Funk, Markus Lutz, Gerhard Wucher, Jochen Franz
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Publication number: 20040099043Abstract: In an angular velocity sensor including two oscillators, the oscillators are balanced in weight precisely, thus providing improved output characteristics. In the sensor, at least one of the two oscillators has a notch having a surface roughness of not higher than 2 &mgr;m on an edge thereof.Type: ApplicationFiled: January 27, 2003Publication date: May 27, 2004Inventors: Tomomasa Omawari, Hiroyuki Tsubonouchi
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Patent number: 6739192Abstract: An angular velocity sensor structured so as to reduce the application of external vibrations to tuning fork as described below. Supporting plate having plate having placement part for placing first rubber body over the top face thereof is placed above the top face of second base via at least two supports so as to provide space between the top face of second base and the supporting plate. First cover and fist base housing tuning fork are placed on first rubber body. Further placed on first cover is second rubber body. The top face of supporting plate and the inner ceiling of second cover compress and hold first rubber body and second rubber body therein.Type: GrantFiled: July 25, 2002Date of Patent: May 25, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideo Okoshi, Shoichi Takeno, Katsuhiko Omoto
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Patent number: 6732586Abstract: The present invention presents an angular velocity sensor having a self diagnosis function. An angular velocity sensor of the present invention includes a driving part for stably vibrating a driving part of a sensor element having a driver part and a detector part for detecting an angular velocity. The angular velocity sensor also includes a detection means for detecting the angular velocity of the sensor element. The angular velocity sensor obtains a self diagnosis signal for a malfunction by detecting a mechanical coupling signal obtained at the detection means.Type: GrantFiled: November 21, 2002Date of Patent: May 11, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Toshiyuki Nozoe, Takeshi Uemura, Masami Tamura
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Patent number: 6722200Abstract: The invention relates to the application of the techniques of nanoelectromechanical systems (NEMS) to ultrasensitive mass detection. A pulsed flux of atoms is adsorbed onto the surface of a 32.8 MHz nanomechanical resonator within an ultrahigh vacuum environment. The mass-induced frequency shifts from these adsorbates are then used to demonstrate a mass sensitivity of ˜1.46×106 Daltons (Da). For resonators operating up to frequencies of 72 MHz, inverse mass responsivities as small as ˜8×10−20 grams/Hz (5×104 Da/Hz) are obtained. Our results offer a new approach to ultrahigh resolution mass spectrometry of individual, electrically-neutral macromolecules with clear prospects for single Dalton sensitivity.Type: GrantFiled: May 3, 2002Date of Patent: April 20, 2004Assignee: California Institute of TechnologyInventors: Michael L. Roukes, Kamil L. Ekinci
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Patent number: 6718292Abstract: A method for designing a sensor using a dual double-ended tuning forks which provides composite cancellation of second-order non-linearity terms.Type: GrantFiled: August 14, 2000Date of Patent: April 6, 2004Assignee: Honeywell International Inc.Inventors: Graeme A. Blake, Paul H. Collins, Steven A. Foote, Ronald B. Leonardson
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Patent number: 6701785Abstract: Tuning fork and method in which a pair of elongated tines having front and rear surfaces are disposed symmetrically about an axis, and balancing masses on the front surface of one tine and on the rear surface of the other tine are trimmed to reduce quadrature error and also to maintain mass balance between the tines.Type: GrantFiled: June 26, 2001Date of Patent: March 9, 2004Assignee: BEI Technologies, Inc.Inventors: Stuart J. Knowles, Robert H. Moore
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Patent number: 6701786Abstract: The present invention provides an apparatus and method for measuring the angular rotation of a moving body. The apparatus comprises an upper sensor layer, a lower handle layer substantially parallel to the sensor layer, at least one dither frame formed of the upper sensor layer, the frame having a dither axis disposed substantially parallel to the upper sensor layer and the lower handle layer. The apparatus further comprises a first accelerometer formed of the upper sensor layer and having a first force sensing axis perpendicular to the dither axis for producing a first output signal indicative of the acceleration of the moving body along the first force sensing axis, the first accelerometer having a proof mass and at least one flexure connecting the proof mass to the dither frame such that the proof mass can be electrically rotated perpendicular to the dither axis.Type: GrantFiled: April 29, 2002Date of Patent: March 9, 2004Assignee: L-3 Communications CorporationInventor: Rand H. Hulsing, II
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Patent number: 6698292Abstract: An object of the present invention is to reduce the zero point temperature drift of a vibrator and the deviation or change of the drift among vibrators actually fabricated. A vibrator has a driving vibration piece 2A, a detection vibration piece and a base portion connecting the driving and detection vibration pieces. The driving vibration piece 2A is composed of a bending vibration piece having a pair of surfaces 2c and 2d parallel with each other and a pair of side faces 2a and 2b. The driving vibration piece 2A has a ratio (WD/TD) of a width WD to a thickness TD of not smaller than 1.5 and not larger than 2.4.Type: GrantFiled: March 10, 2003Date of Patent: March 2, 2004Assignee: NGK Insulators, Ltd.Inventor: Takayuki Kikuchi
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Publication number: 20040035206Abstract: A capacitive sensor such as a tuning-fork gyroscope or accelerometer having a reduced bias error. The electrical connection of the first capacitive plate to, e.g., a signal measuring device or a voltage source, induces a first voltage difference at the junction. The materials of the second capacitive plate are selected such that its electrical connection to, e.g., a signal measuring device or a voltage source, induces a second voltage difference that substantially offsets the first voltage difference and reduces the bias error. One embodiment forms the capacitive plates, e.g., a proof mass and a sense plate, from substantially identical doped semiconductors.Type: ApplicationFiled: March 26, 2003Publication date: February 26, 2004Inventors: Paul A. Ward, Jeffrey T. Borenstein, Christopher M. Lento
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Publication number: 20040007065Abstract: A tuning fork vibrator includes a long plate-shaped vibration unit having a first principal surface and a second principal surface, a base disposed at one end of the second principal surface of the vibration unit in the longitudinal direction, and a slit for dividing the vibration unit into two legs defining a tuning fork along the longitudinal direction symmetrically in the width direction of the vibration unit. The slit is formed so as to include a portion of the base in the vicinity to the vibration unit.Type: ApplicationFiled: June 4, 2003Publication date: January 15, 2004Applicant: Murata Manufacturing Co., Ltd.Inventors: Katsumi Fujimoto, Hironari Yamamoto
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Patent number: 6675652Abstract: An angular velocity of the present invention includes a resonator formed of a resonating member and a connecting member, a first base connected to the connecting member, a holding plate to hold the first base, a circuit board fixed onto the holding plate, an elastic body disposed on an end part of at least one selected from the holding plate and circuit board, a case housing the resonator, first base, holding plate, circuit board and elastic body and provided with an opening, and a second base put in place so as to close the opening of the case. The resonator has a short side and a long side.Type: GrantFiled: February 12, 2002Date of Patent: January 13, 2004Assignee: Matsushita Electric Industrial Co., Ltd.Inventor: Toshio Yamazaki
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Patent number: 6666091Abstract: An angular velocity sensor with improved detection chacteristics using a tuning fork vibrator made of a single crystalline piezoelectric material such as quartz. The turning fork vibrator includes two vibrators bonded together to provide an integral structure so that the vibrators by their respective crystal axis directions generate a piezoelectric phenomena in inverse polarities in their width directions. The tuning fork vibrator has two tuning fork arms and a tuning fork base. Two detection electrodes are respectively disposed on outer faces of the two tuning fork arms. And two other detection electrodes are respectively disposed on inner faces of the two tuning fork arms. Two drive electrodes are respectively disposed on the two tunings fork arms.Type: GrantFiled: August 23, 2002Date of Patent: December 23, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masakazu Hatanaka, Satoshi Ouchi, Toshiyuki Nozoe, Shusaku Kawasaki
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Patent number: 6651498Abstract: A vibratory gyroscope for detecting a turning angular rate of rotation applied to a vibrator in a predetermined temperature range is disclosed. The vibratory gyroscope has a vibrator, a supporting member for supporting the vibrator and an adhesive portion made of an adhesive provided between the supporting member and the vibrator for bonding the vibrator to the supporting member. The vibratory gyroscope detects a turning angular rate based on a detecting vibration excited in the vibrator according to rotation when a driving vibration is excited in the vibrator. The adhesive has a tan &dgr; not higher than 0.1 within the temperature range.Type: GrantFiled: June 29, 2000Date of Patent: November 25, 2003Assignee: NGK Insulators, Ltd.Inventors: Takayuki Kikuchi, Shosaku Gouji, Yukihisa Osugi, Takao Soma, Yuji Fujiwara
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Patent number: 6647786Abstract: A tuning-fork type vibration gyro enables to suppress pyroelectric noise caused by temperature change and to obtain sensor output having high signal-to-noise ratio. The tuning-fork type vibration gyro includes a tuning-fork type vibration body having two arms mutually disposed in parallel and a base for commonly supporting one end of the each arm, wherein a longitudinal direction of the two arms is defined as a z-axis and a perpendicular direction thereto is defined as an x-axis; driving electrodes respectively formed on the two arms for generating vibration of the two arms in a direction parallel to the x-axis; detecting electrodes respectively formed on the two arms for detecting electromotive force generated when the tuning-fork type vibration body is rotated around the z-axis; and dummy electrodes formed on the two arms in respective areas different from the driving electrodes and the detecting electrodes.Type: GrantFiled: August 16, 2001Date of Patent: November 18, 2003Assignee: Fujitsu Media Devices LimitedInventors: Kazuhiro Ohta, Masanori Yachi, Yoshitaka Takahashi, Kazutsugu Kikuchi, Keiji Saito
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Publication number: 20030183006Abstract: By applying a first value of voltage to a first side of a MEMS gyroscope and applying a second value of voltage to a second side of the MEMS gyroscope, the start time of the MEMS gyroscope may be improved. The first and second value of voltage may be provided by a bias power source, such as a battery or a super capacitor. The first value of voltage may be substantially equal in magnitude to and opposite in polarity to the second value of voltage. The bias power source may also be applied to drive electronics connected to the MEMS gyroscope. The bias power source may prevent amplifiers within the drive electronics from saturating during the start time.Type: ApplicationFiled: April 2, 2002Publication date: October 2, 2003Applicant: Honeywell International Inc.Inventors: William P. Platt, Mark W. Weber
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Patent number: 6619122Abstract: An angular velocity sensor has a tuning-fork-type vibrator securely and stably fixed to a support block. A base of a tuning-fork-type vibrator is embedded and fixed into a mounting recess formed in the support block with an adhesive.Type: GrantFiled: August 30, 2001Date of Patent: September 16, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventor: Toshiyuki Nozoe
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Patent number: 6598475Abstract: A micromechanical inertial sensor is provided having a reduced pickoff Q, while maintaining a high motor Q. The micromechanical inertial sensor includes a pair of proof masses and aligned pickoff plates. Each pickoff plate is spaced from the respective proof mass by a gap that varies in response to out-of-plane movement of the proof mass. The micromechanical inertial sensor also includes at least one voltage source for providing charge to the pickoff plates. By measuring the movement of charge in each electrical circuit that includes a pickoff plate as the gap between the pickoff plate and the respective proof mass varies, a measurement of the rotation of the micromechanical inertial sensor about an input axis may be obtained. The micromechanical inertial sensor further includes resistive elements disposed in series between the voltage source and each pickoff plate to increase the pickoff resonance damping of the micromechanical inertial sensor.Type: GrantFiled: September 20, 2001Date of Patent: July 29, 2003Assignee: Honeywell International Inc.Inventor: John C. Pinson
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Patent number: 6598476Abstract: Here disclosed is an angular velocity sensor with much accuracy, not allowing other vibration components to mix into the Coriolis force component. The angular velocity sensor contains a first through a fifth beams: the first, the second, and the third beams have a length of substantially the same and disposed in a substantially parallel arrangement on a substantially the same plane—with the first beam placed between the second and the third; the fourth connects each one end of the first through the third, while the fifth connects each other end of them. The first beam is supportively fixed at its mid-portion. The first beam serves as a detector; the second serves as a driver; and the third serves as a monitor.Type: GrantFiled: March 19, 2002Date of Patent: July 29, 2003Assignee: Matsushita Electric Industrial Co. Ltd.Inventors: Jiro Terada, Katsunori Matsubara, Takeshi Yamamoto
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Patent number: 6584843Abstract: A gyroscope includes a tuning fork, which includes a plurality of tines formed of a conductive material and a supporting portion; an upper glass substrate and a lower glass substrate which sandwich the tuning fork; drive electrodes which are provided on each of the upper and the lower glass substrates in such a manner that parts of the drive electrodes oppose the tines and the remaining parts protrude from the tines, the drive electrodes being capacitively coupled to the tines and driving the tines in a direction parallel to the substrates; and detection electrodes which are capacitively coupled to the tines, and which detect displacements of the tines in a direction perpendicular to the vibrating direction of the tines.Type: GrantFiled: May 22, 2001Date of Patent: July 1, 2003Assignees: Alps Electric Co., Ltd.Inventors: Munemitsu Abe, Masayoshi Esashi
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Patent number: 6584841Abstract: An angular rate sensor is characterized by having electrodes constituting an exciting unit for providing a vibrator with vibration, an electrode constituting a means for detecting a vibration level of the vibrator, an electrode constituting a first detection means for detecting Coriolis' force generated responsive to an angular rate, a second detecting electrode for detecting a signal of reverse polarity to that of the first detecting electrode, a driving circuit for taking as an input a signal from the electrode for detecting the vibration level and outputting a signal to the electrodes, and a first detection circuit and a second detection circuit for taking respective inputs of detected signals from the first detecting electrode and the second detecting electrode.Type: GrantFiled: July 5, 2000Date of Patent: July 1, 2003Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Toshihiko Ichinose, Motoki Ogata, Junichi Yukawa, Koji Yamamoto, Masahiro Saito, Takeshi Uemura
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Patent number: 6584844Abstract: A gyroscopic measuring apparatus with a mechanical resonator comprises at least four identical, parallel vibrating beams integral with a common base and having the same natural frequency. Each beam supports piezoelectric elements for excitation purposes and for detecting vibration of the beam. The base is cruciform and the beams are disposed respectively at ends of branches of a cross formed by the base.Type: GrantFiled: July 25, 2001Date of Patent: July 1, 2003Assignee: Sagem SAInventor: José Beitia
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Patent number: 6578420Abstract: A three-axis micro-gyro structure having first and second micro-gyro devices that measure angular velocity around first and second rate axes extending in a plane of the micro-gyro structure and a third micro-gyro that measures angular velocity around a third rate axis perpendicular to the plane of the micro-gyro structure.Type: GrantFiled: June 26, 2000Date of Patent: June 17, 2003Assignee: Microsensors, Inc.Inventor: Ying Wen Hsu
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Patent number: 4978503Abstract: A specifically-reactive sample-collecting and testing device possessing a cavity or cavities each having a dimension small enough to enable sample liquid to be drawn into the cavity by capillary action, wherein a surface of the cavity carries an immobilized reagent appropriate to the test to be carried out in the device, and wherein said surface is a surface of a transparent solid plate to act as a light-transmissive waveguide and forming a wall of the cavity, said plate having an edge which is substantially optically smooth and transverse to the plane of the plate.Type: GrantFiled: September 6, 1988Date of Patent: December 18, 1990Assignee: Ares-Serono Research & Development Limited PartnershipInventors: Ian A. Shanks, Alan M. Smith