Capacitive Sensor Patents (Class 73/514.32)
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Publication number: 20080302184Abstract: First and second semiconductor layers are attached to each other with an insulation layer sandwiched therebetween. An acceleration sensor device is formed in the first semiconductor layer. A control device for controlling the acceleration sensor device is formed on the second semiconductor layer. Through holes are formed in the second semiconductor layer, and an insulation layer is formed to cover the wall surfaces of the through holes. Through interconnections are formed within the through holes for electrically connecting the acceleration sensor device and the control device to each other. Accordingly, it is possible to obtain an acceleration sensor having excellent detection accuracy while having a reduced size, and a fabrication method thereof.Type: ApplicationFiled: November 28, 2007Publication date: December 11, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Yasuo Yamaguchi, Makio Horikawa, Mika Okumura, Kimitoshi Sato, Takeshi Murakami
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Patent number: 7461553Abstract: An oversampling electromechanical modulator, including a micro-electromechanical sensor which has a first sensing capacitance and a second sensing capacitance and supplies an analog quantity correlated to the first sensing capacitance and to the second sensing capacitance; a converter stage, which supplies a first numeric signal and a second numeric signal that are correlated to the analog quantity; and a first feedback control circuit for controlling the micro-electromechanical sensor, which supplies an electrical actuation quantity correlated to the second numeric signal.Type: GrantFiled: December 5, 2006Date of Patent: December 9, 2008Assignee: STMicroelectronics S.r.l.Inventors: Ernesto Lasalandra, Fabio Pasolini, Valeria Greco
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Patent number: 7456731Abstract: A substrate forming a sensor element is connected to a non-inverting input terminal of an operational amplifier, and a common voltage is applied thereto from a reference voltage supply circuit to fix them to the same potential. Thus, the impedances of the non-inverting input terminal and of the inverting input terminal of the operational amplifier are matched with respect to the power source. Therefore, noise superposed on a power source line can be greatly decreased by noise-removing characteristics determined by CMRR characteristics of the operational amplifier. As a result, a capacitive-type acceleration sensor exhibits sensor characteristics of frequency noise suppressing effect.Type: GrantFiled: May 2, 2006Date of Patent: November 25, 2008Assignee: DENSO CORPORATIONInventors: Akinobu Umemura, Junji Hayakawa, Takaaki Kawai
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Publication number: 20080282802Abstract: An accelerometer or a seismometer using an in-plane suspension geometry having a suspension plate and at least one fixed capacitive plate. The suspension plate is formed from a single piece and includes an external frame, a pair of flexural elements, and an integrated proof mass between the flexures. The flexural elements allow the proof mass to move in the sensitive direction in the plane of suspension while restricting movement in all off-axis directions. Off-axis motion of the proof mass is minimized by the use of intermediate frames disbursed within and between the flexural elements. Intermediate frames can include motion stops to prevent further relative motion during overload conditions. The device can also include a dampening structure, such as a spring or gas structure that includes a trapezoidal piston and corresponding cylinder, to provide damping during non-powered states. The capacitive plate is made of insulating material.Type: ApplicationFiled: May 1, 2006Publication date: November 20, 2008Inventors: William T. Pike, Ian Standley
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Patent number: 7444873Abstract: A comb capacitive accelerometer comprising a substrate, a mobile electrode relative to said substrate fitted with a plurality of mobile fingers, an electrode fixed relative to said substrate fitted with a plurality of fixed fingers, each of said mobile fingers being positioned between two contiguous fixed fingers so as to form a microstructure with interdigital combs. According to the invention the mobile fingers are connected to one another by at least a first connecting beam etched directly into the substrate, and/or the fixed fingers are connected to one another by at least a second connecting beam etched directly in the substrate.Type: GrantFiled: December 19, 2005Date of Patent: November 4, 2008Assignee: Commissariat A l'Energie AtomiqueInventor: Philippe Robert
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Publication number: 20080257045Abstract: A sensor device includes a sensor chip, a circuit chip, a casing, a first adhesive member disposed between the sensor chip and the circuit chip, and a second adhesive member disposed between the circuit chip and the casing. The first adhesive member has an area smaller than that of the sensor chip and a distance between the first adhesive member and an outer peripheral edge of the sensor chip becomes a minimum at a portion adjacent to a centerline of the sensor chip. The second adhesive member has an area smaller than that of the circuit chip and a distance between the second adhesive member and an outer peripheral edge of the circuit chip becomes a minimum at a portion adjacent to a centerline of the circuit chip.Type: ApplicationFiled: April 10, 2008Publication date: October 23, 2008Applicant: DENSO CORPORATIONInventor: Masaki Takashima
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Patent number: 7434466Abstract: The electrostatically-driven/capacitance-detection type gyro sensor has a sensing element including a movable part, the sensitivity of the sensing element and accordingly the sensitivity of a sensor output signal thereof being kept unchanged by controlling the amplitude of displacement or displacing velocity of the movable part and by using a reference voltage independent of variation of a power supply voltage, even there occurs a change in the vibrating state of the movable part due to temperature change or secular variation.Type: GrantFiled: December 9, 2005Date of Patent: October 14, 2008Assignee: Denso CorporationInventor: Hajime Ito
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Patent number: 7434463Abstract: A moving member having a plurality of moving electrodes is supported by support members at both ends thereof on a substrate surface in such a way that it can be subjected to displacement in a two-dimensional plane. A plurality of fixed electrodes are arranged to face the plurality of moving electrodes respectively, thus forming different facing areas therebetween when an input acceleration is zero. The facing areas formed between pairs of the electrodes facing each other are varied in response to the displacement of the moving member, whereby a capacitance caused by one pair of the electrodes whose facing area is relatively small is used to detect a relatively small input acceleration, and a capacitance caused by the other pair of the electrodes whose facing area is relatively large is used to detect a relatively large input acceleration.Type: GrantFiled: August 25, 2005Date of Patent: October 14, 2008Assignee: Yamaha CorporationInventor: Tamito Suzuki
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Patent number: 7430915Abstract: A vibration sensor capable of preventing a diaphragm electrode from being damaged without lowering sensitivity as well as realizing a satisfactory assembling process. The vibration sensor includes a fixed electrode 1, and a diaphragm electrode 3 having a weight member 2 attached to a membrane surface facing away from the fixed electrode 1 and fixedly supported at peripheries thereof, the vibration sensor being capable of outputting variation of capacitance between the fixed electrode and the diaphragm electrode as vibration signals. The vibration sensor further includes projecting portions 2a formed on parts of an end portion of the weight member 2 to project along the direction of the membrane surface and spaced from the membrane surface of the diaphragm electrode 3, and a restricting member 4 for contacting the projecting portions 2a of the weight member 2 displaced along the direction of the membrane surface of the diaphragm electrode 3, thereby to restrict displacement of the weight member 2.Type: GrantFiled: August 31, 2004Date of Patent: October 7, 2008Assignee: Hosiden CorporationInventors: Mamoru Yasuda, Yasuo Sugimori, Takahisa Ohtsuji
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Patent number: 7432724Abstract: A capacitive sensor for detecting a physical quantity includes a movable electrode and a fixed electrode, and a controlling unit for applying a signal between the movable electrode and the fixed electrode. The controlling unit includes an input terminal, an output terminal, and a time measuring means for measuring a time period. The controlling unit measures the time period, for which a diagnosis instruction signal is input into the input terminal. The controlling unit performs the self-diagnosis, after the instruction signal continues for a predetermined time period.Type: GrantFiled: November 14, 2006Date of Patent: October 7, 2008Assignee: DENSO CORPORATIONInventor: Keisuke Goto
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Patent number: 7426863Abstract: The present invention relates to measuring devices used in measuring acceleration and, more precisely, to capacitive acceleration sensors. The object of the invention is to provide an improved method of manufacturing a capacitive acceleration sensor, and to provide a capacitive acceleration sensor, which is applicable for use in small capacitive acceleration sensor solutions, and which, in particular, is applicable for use in small and extremely thin capacitive acceleration sensor solutions measuring acceleration in relation to several axes.Type: GrantFiled: June 16, 2006Date of Patent: September 23, 2008Assignee: VTI Technologies OyInventor: Heikki Kuisma
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Patent number: 7426861Abstract: A tuning fork gyroscope design where at least one proof mass is supported above a substrate. At least one drive electrode is also supported above the substrate adjacent the proof mass. Typically, the proof mass and the drive electrode include interleaved electrode fingers. A sense plate or shield electrode on the substrate beneath the proof mass extends completely under the extent of the electrode fingers of proof mass.Type: GrantFiled: June 15, 2005Date of Patent: September 23, 2008Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Marc S. Weinberg, Jonathan Bernstein, Jeffrey T. Borenstein, Richard Elliott, Gregory Kirkos, Anthony S. Kourepenis
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Publication number: 20080216572Abstract: A physical quantity sensor includes: a substrate; a movable element; two fixed elements; a carrier wave application element for applying two carrier waves to the fixed elements; a signal application element for applying a middle voltage to the movable element; and a detection circuit for detecting a physical quantity. The detection circuit executes a first self diagnosis process when the signal application element further applies a first self diagnosis signal to the movable element. The first self diagnosis signal has a first frequency for obtaining a resonant magnification equal to or larger than 1.1 times with respect to a resonant frequency of the movable element, so that the movable element is resonated and almost contacts or press contacts one fixed element. The detection circuit determines whether a sticking phenomenon occurs when the signal application element applies the first self diagnosis signal.Type: ApplicationFiled: November 1, 2007Publication date: September 11, 2008Applicant: DENSO CORPORATIONInventor: Seiki Aoyama
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Publication number: 20080210008Abstract: A flexible substrate (110) having flexibility and a fixed substrate (120) disposed so as to oppose it are supported at their peripheral portions by a sensor casing (140). An oscillator (130) is fixed on the lower surface of the flexible substrate. Five lower electrode layers (F1 to F5: F1 and F2 are disposed at front and back of F5) are formed on the upper surface of the flexible substrate. Five upper electrode layers (E1 to E5) are formed on the lower surface of the fixed substrate so as to oppose the lower electrodes. In the case of detecting an angular velocity ?x about the X-axis, an a.c. voltage is applied across a predetermined pair of opposite electrode layers (E5, F5) to allow the oscillator to undergo oscillation Uz in the Z-axis direction. Thus, a Coriolis force Fy proportional to the angular velocity ?x is applied to the oscillator in the Y-axis. By this Coriolis force Fy, the oscillator is caused to undergo displacement in the Y-axis direction.Type: ApplicationFiled: March 13, 2008Publication date: September 4, 2008Inventor: Kazuhiro Okada
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Patent number: 7418864Abstract: An acceleration sensor includes: a semiconductor substrate including a support layer and a semiconductor layer, which are stacked in a first direction; a movable electrode and a fixed electrode; and a trench. The movable electrode separately faces the fixed electrode by sandwiching the trench along with a second direction. The trench has a detection distance in the second direction. The movable electrode is movable along with the first direction when acceleration is applied. The movable electrode has a bottom apart from the support layer. The width of the movable electrode along with the second direction is smaller than the width of the fixed electrode. The thickness of the movable electrode along with the first direction is smaller than the thickness of the fixed electrode.Type: GrantFiled: March 21, 2006Date of Patent: September 2, 2008Assignee: DENSO CORPORATIONInventors: Kazushi Asami, Yukihiro Takeuchi, Kenichi Yokoyama
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Publication number: 20080196502Abstract: A weight of an inertial sensor if formed from a plurality of divided weights, and the divided weights are connected to each other by elastically deformable beams. A movable range and a mass of each of the divided weights and a rigidity of each of the beams are adjusted and a plurality of deformation modes having different sensitivity ranges with respect to the acceleration are used in combination. By this means, it is possible to improve a detecting sensitivity of an acceleration and widen an acceleration response range.Type: ApplicationFiled: June 15, 2007Publication date: August 21, 2008Inventors: Hiroshi FUKUDA, Yuko Hanaoka, Tsukasa Fujimori
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Publication number: 20080196499Abstract: A transducer package 20 includes a substrate 32 having a first axis of symmetry 36 and a second axis of symmetry 38 arranged orthogonal to the first axis of symmetry 36. At least a first sensor 50 and a second sensor 52 each of which are symmetrically arranged on the substrate 32 relative to one of the first and second axes of symmetry 36 and 38. The first and second sensors 50 and 52 are adapted to detect movement parallel to the other of the first and second axes of symmetry 36 and 38. The first sensor 50 is adapted to detect movement over a first sensing range and the second sensor 52 is adapted to detect movement over a second sensing range, the second sensing range differing from the first sensing range.Type: ApplicationFiled: February 21, 2007Publication date: August 21, 2008Applicant: FREESCALE SEMICONDUCTOR, INC.Inventors: Gary G. Li, Todd F. Miller, David J. Monk
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Publication number: 20080196501Abstract: A semiconductor sensor is disclosed that includes a semiconductor substrate, a sensing portion provided on the semiconductor substrate, and a pad in electrical communication with the sensing portion and provided on the semiconductor substrate. The semiconductor sensor also includes a bonding wire in electrical communication with the pad. Furthermore, the semiconductor sensor includes a cover member with a covering portion disposed over the semiconductor substrate for covering the sensing portion such that the covering portion is separated at a distance from the sensing portion. The cover member further includes a coupling portion provided on the semiconductor substrate at an area including the pad and for enabling electrical connection of the pad with the bonding wire therethrough.Type: ApplicationFiled: April 17, 2008Publication date: August 21, 2008Applicant: DENSO CORPORATIONInventors: Minekazu Sakai, Ryuichiro Abe, Akitoshi Yamanaka
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Patent number: 7412888Abstract: An accelerometer includes a fixing unit and a movable unit. The fixing unit has a plurality of first electrode parts and a plurality of second electrode parts. The movable unit is connected with the fixing unit and includes a body having an opening, a plurality of third electrode parts and a plurality of fourth electrode parts. The third electrode parts are disposed at an outer side of the body with respect to the first electrode parts, respectively. The fourth electrode parts are disposed at the inner side of the body in the opening, and are disposed respectively with respect to the second electrode parts, respectively.Type: GrantFiled: November 2, 2006Date of Patent: August 19, 2008Assignee: Delta Electronics, Inc.Inventors: Chia-Yi Chu, Heng-Chung Chang, Chuan-Wei Wang, Chih-Ming Sun, Wei-Leun Fang, Shiang-Cheng Lu, Hsieh-Shen Hsieh, Horng-Jou Wang, Tai-Kang Shing, Huang-Kun Chen
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Patent number: 7412887Abstract: One or more fixed sensing electrodes are employed to sense movement of a mass both within the plane of the mass/electrodes and along an axis normal to that plane. In order to measure movement of the mass along the axis normal to the plane, a reference capacitance is measured between the fixed sensing electrode(s) and an underlying conducting plane and a measurement capacitance is measured between the mass and the underlying conducting plane. A value Cv-KCf may be computed, where Cf is the reference capacitance, Cv is the measurement capacitance, and K is a predetermined constant. In accordance with certain embodiments of the invention, a standard one or two axis acceleration sensor that measures movement of the mass within the plane can be used to also measure movement of the mass in the axis normal to the plane.Type: GrantFiled: August 16, 2005Date of Patent: August 19, 2008Assignee: Analog Devices, Inc.Inventor: John Memishian
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Publication number: 20080190203Abstract: A signal amplifying circuit having a small-scaled circuit arrangement and exhibiting a low power consumption is provided without degrading the detection precision of an electrostatic capacity detecting element. A signal amplifying circuit comprising an AC-coupled amplifier; a voltage generating circuit for generating a DC bias voltage that is a reference of AC coupling; and a conveying means for conveying the bias voltage to the amplifier; wherein a very small voltage signal outputted by an electrostatic capacity detecting element is superimposed, as an AC component, on the bias voltage and then amplified. The signal amplifying circuit having the structure described above is characterized in that it is configured such that the input impedance of the conveying means seen from the electrostatic capacity detecting element is higher than the output impedance of the electrostatic capacity detecting element.Type: ApplicationFiled: September 14, 2005Publication date: August 14, 2008Applicant: HOSIDEN CORPORATIONInventor: Yasuo Sugimori
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Publication number: 20080190204Abstract: A variable capacitor including at least two interdigitized combs provided with teeth, the cross section of the end of a tooth adjacent to the other comb being greater than the cross section of the end of a tooth remote from the other comb. The variable capacitor can be used in gyrometers and accelerometers.Type: ApplicationFiled: February 1, 2006Publication date: August 14, 2008Applicant: COMMISSARIAT AL'ENERGIE ATOMIQUEInventors: Jean-Sebastien Danel, Bernard Diem
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Publication number: 20080191714Abstract: A capacitive physical quantity detection device comprises: a plurality of capacitive physical quantity sensors, wherein each sensor including: a detection unit having a movable electrode and a fixed electrode; a C-V conversion circuit having a differential amplifier circuit, wherein a first input terminal of the differential amplifier circuit is coupled with the movable electrode, a second input terminal of the differential amplifier circuit inputs a reference voltage and a self-diagnosis voltage therein during a normal operation and a self-diagnosis operation, respectively, and the C-V conversion circuit outputs an output voltage; and a signal processing circuit that performs a signal processing of the output voltage, wherein the reference voltage in each sensor is almost the same, the plurality of sensors performs the self-diagnosis operation simultaneously, the self-diagnosis voltage in one of the sensors is a first self-diagnosis voltage is different from the self-diagnosis voltage in another one of the sType: ApplicationFiled: January 17, 2008Publication date: August 14, 2008Applicant: DENSO CORPORATIONInventors: Masashi Masuda, Junji Hayakawa
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Patent number: 7409862Abstract: A Micro Electromechanical Systems (MEMS) accelerometer device having a proof mass flexibly attached to a substrate. The device includes one or more sense capacitors formed between the proof mass and the substrate, one or more torque capacitors formed between the proof mass and the substrate, and an isolation device that electrically isolates cathodes of the sense capacitors from cathodes of the torque capacitors on the proof mass.Type: GrantFiled: October 18, 2006Date of Patent: August 12, 2008Assignee: Honeywell International Inc.Inventor: Mark T. Derbyshire
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Publication number: 20080178675Abstract: An electrode layer is formed on the upper surface of a first substrate, and a processing for partially removing the substrate is carried out in order to allow the substrate to have flexibility. To the lower surface of the first substrate, a second substrate is connected. Then, by cutting the second substrate, a working body and a pedestal are formed. On the other hand, a groove is formed on a third substrate. An electrode layer is formed on the bottom surface of the groove. The third substrate is connected to the first substrate so that both the electrodes face to each other with a predetermined spacing therebetween. Finally, the first, second and third substrates are cut off every respective unit regions to form independent sensors, respectively. When an acceleration is exerted on the working body, the first substrate bends. As a result, the distance between both the electrodes changes. Thus, an acceleration exerted is detected by changes in an electrostatic capacitance between both the electrodes.Type: ApplicationFiled: March 14, 2008Publication date: July 31, 2008Inventor: Kazuhiro Okada
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Publication number: 20080173091Abstract: A differential capacitive sensor (50) includes a movable element (56) pivotable about a rotational axis (60). The movable element (56) includes first and second sections (94, 96). The first section (94) has an extended portion (98) distal from the rotational axis (60). A static layer (52) is spaced away from a first surface (104) of the moveable element (56), and includes a first actuation electrode (74), a first sensing electrode (64), and a third sensing electrode (66). A static layer (62) is spaced away from a second surface (106) of the moveable element (56) and includes a second actuation electrode (74), a second sensing electrode (70), and a fourth sensing electrode (72). The first and second electrodes (64, 70) oppose the first section (94), the third and fourth electrodes (66, 72) oppose the second section (96), and the first and second electrodes (68, 74) oppose the extended portion (98).Type: ApplicationFiled: January 18, 2007Publication date: July 24, 2008Applicant: Freescale Semiconductor, Inc.Inventors: Andrew C. McNeil, Yizhen Lin, Todd F. Miller
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Publication number: 20080168838Abstract: A MEMS sensor includes a substrate having a MEMS structure movably attached to the substrate, a cap attached to the substrate and encapsulating the MEMS structure, and an electrode formed on the cap that senses movement of the MEMS structure.Type: ApplicationFiled: January 11, 2008Publication date: July 17, 2008Applicant: ANALOG DEVICES, INC.Inventors: John R. Martin, Xin Zhang
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Patent number: 7400153Abstract: A detector for detecting an object that may be feared to or about to be caught by a closing door such as a slide door of a vehicle incorporates a capacitance sensor with a directionality characteristic in the direction of its detection surface. The detector has a main body enclosing detection electrodes, an insulating material placed in between and a shield electrode serving to provide the directionality. A protective cover may cover the shield electrode and the detection electrodes. A water-repellant finish may be provided at least on a portion of the outer surface of the main body including the detection surface for preventing water drops from remaining or becoming larger. A plurality of mutually adjacent protrusions may be formed on the protective cover with thickness decreasing in the direction of protrusion for making it difficult for water drops to remain.Type: GrantFiled: April 20, 2006Date of Patent: July 15, 2008Assignees: OMRON Corporation, Honda Motor Co., Ltd., Mitsuba CorporationInventors: Shinichi Shoji, Akihiro Okushima, Hiroyuki Sueyasu, Keiichi Nagayama, Yukinori Kurumado
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Patent number: 7398683Abstract: The invention relates to measuring devices used in the measurement of acceleration and, more specifically, to capacitive acceleration sensors. The capacitive acceleration sensor according to the present invention contains a movable electrode (5) of the acceleration sensor supported at an axis of rotation (7). Several pairs of electrodes are utilized in the acceleration sensor according to the present invention. Advantages of symmetry are achieved with the acceleration sensor structure according to the present invention, and it enables reliable and efficient measuring of acceleration, in particular in small capacitive acceleration sensor designs.Type: GrantFiled: February 10, 2004Date of Patent: July 15, 2008Assignee: VTI Technologies OyInventor: Tuomo Lehtonen
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Publication number: 20080163687Abstract: The MEMS Sensor Suite on a Chip provides the capability, monolithically integrated onto one MEMS chip, to sense temperature, humidity, and two axes of acceleration. The device incorporates a MEMS accelerometer, a MEMS humidity sensor, and a MEMS temperature sensor on one chip. These individual devices incorporate proof masses, suspensions, humidity sensitive capacitors, and temperature sensitive resistors (thermistors) all fabricated in a common fabrication process that allows them to be integrated onto one micromachined chip. The device can be fabricated in a simple micromachining process that allows its size to be miniaturized for embedded and portable applications. During operation, the sensor suite chip monitors temperature levels, humidity levels, and acceleration levels in two axes. External circuitry allows sensor readout, range selection, and signal processing.Type: ApplicationFiled: March 20, 2008Publication date: July 10, 2008Applicant: Morgan Research CorporationInventors: Michael Scott Kranz, Robert Faye Elliott, Michael Ray Whitley, Marty Ray Williams, Philip John Reiner
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Publication number: 20080141774Abstract: An acceleration sensor includes a seismic mass which is suspended on springs above a substrate and is deflectable in a direction perpendicular to a surface of the substrate. In order to reduce deflections of the seismic mass along the surface of the substrate because of interference accelerations, which lead to a falsification of the measurements of the deflection of the seismic mass perpendicular to the surface of the substrate, the springs include two bending bars which are interconnected via crosspieces.Type: ApplicationFiled: November 13, 2007Publication date: June 19, 2008Inventors: Johannes Classen, Markus Heitz, Lars Tebje, Fouad Bennini
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Publication number: 20080134785Abstract: A micromechanical inertial sensor having at least one seismic mass which may be deflected relative to a substrate, and at least one electrode surface which in terms of circuitry, together with at least portions of the seismic mass forms at least one capacitor having a capacitance which is dependent on the deflection of the seismic mass. At least one additional auxiliary electrode is included which is located outside the region which forms the capacitor and which may be set at a potential that deviates from the potential of the seismic mass.Type: ApplicationFiled: November 20, 2007Publication date: June 12, 2008Inventor: Odd-Axel Pruetz
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Publication number: 20080110260Abstract: First and second detection frames are supported by a substrate to be rotatable about first and second torsion axes. A first link beam is connected to the first detection frame on an axis located at a position moved from a position of the first torsion axis in a first direction crossing the first torsion axis and directed to one end side of the first detection frame. A second link beam is connected to the second detection frame on an axis located at a position shifted from a position of the second torsion axis in a second direction opposite to the first direction. An inertia mass body is displaceable in a thickness direction of the substrate by being linked with the first and second detection frames by the first and second link beams, respectively. This constitution makes it possible to obtain a highly precise acceleration sensor hardly influenced by disturbances.Type: ApplicationFiled: November 1, 2007Publication date: May 15, 2008Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Nobuaki KONNO, Yoshiaki Hirata
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Patent number: 7363816Abstract: In an inertial sensor, a mass is supported by a number of mass support structures positioned within an inner periphery of the mass. The mass support structures are affixed to a substrate by at least one anchor positioned proximate to the mass' center of mass. A number of sensing fingers are affixed to the mass support structures.Type: GrantFiled: November 13, 2006Date of Patent: April 29, 2008Assignee: Analog Devices, Inc.Inventors: Michael W. Judy, Howard R. Samuels
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Publication number: 20080092654Abstract: A Micro Electromechanical Systems (MEMS) accelerometer device having a proof mass flexibly attached to a substrate. The device includes one or more sense capacitors formed between the proof mass and the substrate, one or more torque capacitors formed between the proof mass and the substrate, and an isolation device that electrically isolates cathodes of the sense capacitors from cathodes of the torque capacitors on the proof mass.Type: ApplicationFiled: October 18, 2006Publication date: April 24, 2008Applicant: HONEYWELL INTERNATIONAL INC.Inventor: Mark T. Derbyshire
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Patent number: 7360425Abstract: A method for constructing a compensated composite structure, including a support tube coupled to a flexure plate and enclosing a capacitor plate, includes selecting a material for the support tube whereby the coefficient of expansion is larger than that of the material of the capacitor plates. Further, the method includes selecting the lengths of the support tube and the capacitor plate such that the composite structure is insensitive to changes in temperature.Type: GrantFiled: November 22, 2004Date of Patent: April 22, 2008Assignee: The Boeing CompanyInventors: Ray F. Campbell, Joan D. Wada, Michael J. Costello, Mohsen A. Khatiblou
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Publication number: 20080087085Abstract: A transducer (20) includes a movable element (24), a self-test actuator (22), and a sensing element (56, 58). The sensing element (56, 58) detects movement of the movable element (24) from a first position (96) to a second position (102) along an axis perpendicular to a plane of the sensing element (56, 58). The second position (102) results in an output signal (82) that simulates a free fall condition. A method (92) for testing a protection feature of a device (70) having the transducer (20) entails moving the movable element (24) to the first position (102) to produce a negative gravitational force detectable at the sensing element (56, 68), applying a signal (88) to the actuator (22) to move the movable element (24) to the second position (102) by the electrostatic force (100) , and ascertaining an enablement of the protection feature in response to the simulated free fall.Type: ApplicationFiled: October 11, 2006Publication date: April 17, 2008Inventors: Akihiro Ueda, Andrew C. McNeil
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Patent number: 7355782Abstract: An interference modulator (Imod) incorporates anti-reflection coatings and/or micro-fabricated supplemental lighting sources. An efficient drive scheme is provided for matrix addressed arrays of IMods or other micromechanical devices. An improved color scheme provides greater flexibility. Electronic hardware can be field reconfigured to accommodate different display formats and/or application functions. An IMod's electromechanical behavior can be decoupled from its optical behavior. An improved actuation means is provided, some one of which may be hidden from view. An IMod or IMod array is fabricated and used in conjunction with a MEMS switch or switch array. An IMod can be used for optical switching and modulation. Some IMods incorporate 2-D and 3-D photonic structures. A variety of applications for the modulation of light are discussed. A MEMS manufacturing and packaging approach is provided based on a continuous web fed process.Type: GrantFiled: November 29, 2006Date of Patent: April 8, 2008Assignee: IDC, LLCInventor: Mark W. Miles
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Patent number: 7350415Abstract: A closed-loop, comb drive device that reduces certain “common mode” sensor errors. The device includes a comb structure, electronics, a substrate, and a position sensor. The comb structure includes two comb-drive sections, each having at least two subsections. The comb drive sub-sections in each section are positioned in a diagonal relationship to each other relative to the device axes. A separate pick-off section, along with the electronics, determine which of the two drive sections should receive a voltage differential, and the size of that differential. The diagonal relationship within each drive section eliminates many of the large scale factor errors which often occur in prior-art designs.Type: GrantFiled: May 25, 2006Date of Patent: April 1, 2008Assignee: Honeywell International Inc.Inventor: Peter LaFond
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Patent number: 7343801Abstract: A micromechanical capacitive acceleration sensor is described for picking up the acceleration of an object in at least one direction. The sensor includes a frame structure (110), a sensor inertia mass (101) made of a wafer and movably mounted relative to the frame structure (110) about a rotation axis, and a capacitive pick-up unit (120) for producing at least one capacitive output signal representing the position of the sensor mass (101) relative to the frame structure (110). The sensor inertia mass (101) has a center of gravity which offset relative to the rotation axis in a direction perpendicularly to a wafer plane for measuring accelerations laterally to the wafer plane. The sensor mass (101) and the frame structure (110) are made monolithically of one single crystal silicon wafer. A cover section (112) forms a common connector plane (150) for the connection of capacitor electrodes (125,126). Torqueable elements (105) form an electrically conducting bearing device for the sensor mass (101).Type: GrantFiled: March 7, 2002Date of Patent: March 18, 2008Assignee: Conti Temic microelectronic GmbHInventors: Konrad Kapser, Peter Knittl, Ulrich Prechtel, Helmut Seidel, Sebastian Toelg, Manfred Weinacht
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Patent number: 7340955Abstract: The present invention relates to measuring devices used in measuring acceleration, and, more specifically, to capacitive acceleration sensors. The improved sensor arrangement of the invention enables reliable and effective measuring of acceleration, in small capacitive acceleration sensor designs, in particular. The acceleration sensor arrangement measuring circuitry of the present invention can also be applied for multi-terminal sensors, such as, for example, acceleration sensors with three axes, by using time division signal multiplexing.Type: GrantFiled: June 23, 2004Date of Patent: March 11, 2008Assignee: VTI Technologies OyInventor: Hannu Manninen
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Patent number: 7340956Abstract: The present disclosure is directed to an apparatus and method for producing and comparing signals from various points in a MEMS device. By producing signals which should be of substantial identical characteristics, deviations from the situation where the signals are of identical characteristics can be used to identify various types of asymmetry which are otherwise difficult to detect. In one embodiment, the MEMS device is comprised of a plurality of fixed beams arranged symmetrically and a plurality of movable beams arranged symmetrically. A first sensor is formed by certain of the fixed and movable beams while a second sensor, electrically isolated from said first sensor, is formed by at least certain other of the fixed and movable beams. The first and second sensors are located within the MEMS device so as to produce signals of substantially identical characteristics. A circuit is responsive to the first and second sensors for comparing the signals produced by the first and second sensors.Type: GrantFiled: March 8, 2006Date of Patent: March 11, 2008Assignee: Carnegie Mellon UniversityInventors: Nilmoni Deb, Ronald D. Shawn Blanton
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Patent number: 7337671Abstract: Disclosed are moveable microstructures comprising in-plane capacitive microaccelerometers, with submicro-gravity resolution (<200 ng/?Hz) and very high sensitivity (>17 pF/g). The microstructures are fabricated in thick (>100 ?m) silicon-on-insulator (SOI) substrates or silicon substrates using a two-mask fully-dry release process that provides large seismic mass (>10 milli-g), reduced capacitive gaps, and reduced in-plane stiffness. Fabricated devices may be interfaced to a high resolution switched-capacitor CMOS IC that eliminates the need for area-consuming reference capacitors. The measured sensitivity is 83 mV/mg (17 pF/g) and the output noise floor is ?91 dBm/Hz at 10 Hz (corresponding to an acceleration resolution of 170 ng/?Hz). The IC consumes 6 mW power and measures 0.65 mm2 core area.Type: GrantFiled: June 1, 2006Date of Patent: March 4, 2008Assignee: Georgia Tech Research Corp.Inventors: Farrokh Ayazi, Babak Vakili Amini, Reza Abdolvand
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Patent number: 7334474Abstract: A force balanced instrument system and method for mitigating errors is provided. The system and method mitigate errors in measurement readings caused by charge buildup in force balanced instruments that employ charge pulses to generate an electrostatic force to null an inertial proof mass disposed between opposing electrodes. The system and method mitigate charge buildup by applying positive charge pulses alternately to each opposing electrode for a given charge cycle time period followed by negative charge pulses alternately to each opposing electrode for a second given charge cycle time period. The negative charge pulses remove any residual charge on the electrodes caused by the positive charge pulses. As a result the net residual charge left on the electrodes is reduced on the average.Type: GrantFiled: January 7, 2005Date of Patent: February 26, 2008Assignee: Litton Systems, Inc.Inventors: J. Alexander Fax, Robert Griffith
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Patent number: 7331229Abstract: An accelerometer system includes a capacitor plate fixed within a housing and a flexure plate positioned substantially parallel to the capacitor plate a distance therefrom. The distance varies in response to acceleration forces acting upon the flexure plate such that the flexure plate and the capacitor plate generate a capacitance signal. A magnet is coupled to the flexure plate and generates a magnetic field, which moves as the flexure plate flexes. A coil winding around the flexure plate generates a second magnetic field as a function of capacitance signal, thus opposing the flexure plate magnetic field, and thereby returning the flexure plate to a null position.Type: GrantFiled: December 9, 2004Date of Patent: February 19, 2008Assignee: The Boeing CompanyInventors: Ray F. Campbell, Joan D. Wada, Michael J. Costello, Mohsen A. Khatiblou
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Publication number: 20080028856Abstract: Provided is a capacitive acceleration sensor including a silicon substrate, which includes a movable electrode having a comb shape and a fixed electrode having a comb shape opposed to the comb shape of the movable electrode, and a pair of glass substrates having a concave portion forming a cavity on at least one side thereof, wherein the silicon substrate and the glass substrates are bonded to each other so that the movable electrode and the fixed electrode is disposed in the cavity. Accordingly, it is possible to provide the capacitive acceleration sensor having a small size and high sensitivity.Type: ApplicationFiled: February 27, 2007Publication date: February 7, 2008Applicant: ALPS ELECTRIC CO., LTDInventors: Katsuya Kikuiri, Kiyoshi Sato, Tetsuya Fukuda
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Patent number: 7322240Abstract: A comb capacity accelerometer including: a substrate, a first mobile electrode free to move with respect to the substrate provided with a set of mobile fingers, a first fixed electrode fixed with respect to the substrate and provided with a set of fixed fingers, each of the mobile fingers being arranged between two contiguous fixed fingers so as to form a first microstructure with interdigitised combs, at least one second mobile electrode associated with at least one second fixed electrode to form at least one second microstructure with interdigitised combs superposed on the first microstructure with interdigitised combs, and the second mobile electrode and the second fixed electrode are etched in the same substrate as the first mobile electrode and the first fixed electrode.Type: GrantFiled: December 19, 2005Date of Patent: January 29, 2008Assignee: Commissariat a l'Energie AtomiqueInventor: Philippe Robert
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Publication number: 20080016964Abstract: A MEMS device includes a substrate; a movable mass suspended in proximity to the substrate; and at least one suspension structure coupled to the movable mass for performing a mechanical spring function. The at least one suspension structure has portions that move in tandem when the MEMS device is subject to at least one stimulus in a sensing direction, and further includes at least one link between the portions that move in tandem.Type: ApplicationFiled: July 19, 2006Publication date: January 24, 2008Inventors: Daniel N. Koury, Andrew C. McNeil
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Patent number: RE40347Abstract: A single crystal silicon substrate (1) is bonded through an SiO2 film (9) to a single crystal silicon substrate (8), and the single crystal silicon substrate (1) is made into a thin film. A cantilever (13) is formed on the single crystal silicon substrate (1), and the thickness of the cantilever (13) in a direction parallel to the surface of the single crystal silicon substrate (1) is made smaller than the thickness of the cantilever in the direction of the depth of the single crystal silicon substrate (1), and movable in a direction parallel to the substrate surface. In addition, the surface of the cantilever (13) and the part of the single crystal silicon substrate (1), opposing the cantilever (13), are respectively, coated with an SiO2 film (5), so that an electrode short circuit is prevented in a capacity-type sensor. In addition, a signal-processing circuit (10) is formed on the single crystal silicon substrate (1), so that signal processing is performed as the cantilever (13) moves.Type: GrantFiled: April 17, 2002Date of Patent: June 3, 2008Assignee: DENSO CorporationInventor: Tetsuo Fujii
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Patent number: RE40561Abstract: A single crystal silicon substrate (1) is bonded through an SiO2 film (9) to a single crystal silicon substrate (8), and the single crystal silicon substrate (1) is made into a thin film. A cantilever (13) is formed on the single crystal silicon substrate (1), and the thickness of the cantilever (13) in a direction parallel to the surface of the single crystal silicon substrate (1) is made smaller than the thickness of the cantilever in the direction of the depth of the single crystal silicon substrate (1), and movable in a direction parallel to the substrate surface. In addition, the surface of the cantilever (13) and the part of the single crystal silicon substrate (1), opposing the cantilever (13), are, respectively, coated with an SiO2 film (5), so that an electrode short circuit is prevented in a capacity-type sensor. In addition, a signal-processing circuit (10) is formed on the single crystal silicon substrate (1), so that signal processing is performed as the cantilever (13) moves.Type: GrantFiled: December 10, 2002Date of Patent: November 4, 2008Assignee: Denso CorporationInventor: Tetsuo Fujii