Abstract: An accelerometer includes a substrate having a surface and a movable electrode. The movable electrode is mounted on the surface of the substrate and movable along an axis substantially parallel to the surface of the substrate in response to acceleration. A light-permeable region is defined in the movable electrode. A plurality of photosensitive regions and a plurality of non-photosensitive regions are defined in the surface of the substrate. The photosensitive regions and the non-photosensitive regions are spatially separated. The light-permeable region overlies only a portion of one of the non-photosensitive regions when at rest, and the light-permeable region overlies a portion of at least one of the photosensitive regions when the accelerometer is subjected to acceleration, such that the corresponding photosensitive region generates an output current.

Abstract: A Micro-Electro-Mechanical Systems (MEMS) inertial sensor systems and methods are operable to determine linear acceleration and rotation. An exemplary embodiment applies a first linear acceleration rebalancing force via a first electrode pair to a first proof mass, applies a second linear acceleration rebalancing force via a second electrode pair to a second proof mass, applies a first Coriolis rebalancing force via a third electrode pair to the first proof mass, applies a second Coriolis rebalancing force via a fourth electrode pair to the second proof mass, determines a linear acceleration corresponding to the applied first and second linear acceleration rebalancing forces, and determines a rotation corresponding to the applied first and second Coriolis rebalancing forces.

Abstract: A method of detecting activity in a MEMS accelerometer captures an acceleration bias, measures acceleration at a predetermined time, calculates a change in acceleration using the measured acceleration and the acceleration bias, and compares the change in acceleration to a threshold to detect activity. A method of detecting inactivity uses a similar technique along with a timer. The method of detecting inactivity in a MEMS accelerometer captures an acceleration bias, measures acceleration at a predetermined time, calculates a change in acceleration using the measured acceleration and the acceleration bias, and compares the change in acceleration to a threshold to detect inactivity. The method further determines if the change in acceleration is less than the threshold and, if so, determines if a predetermined period of time has elapsed to detect inactivity.

Abstract: 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.

Abstract: Disclosed are MEMS accelerometers and methods for fabricating same. An exemplary accelerometer comprises a substrate, and a proof mass that is a portion of the substrate and which is separated from the substrate surrounding it by a gap. An electrically-conductive anchor is coupled to the proof mass, and a plurality of electrically-conductive suspension arms that are separated from the proof mass extend from the anchor and are coupled to the substrate surrounding the proof mass. A plurality of sense and actuation electrodes are separated from the proof mass by gaps and are coupled to processing electronics. Capacitive sensing is used to derive electrical signals caused by forces exerted on the proof mass, and the electrical signals are processed by the processing electronics to produce x-, y- and z-direction acceleration data. Electrostatic actuation is used to induce movements of the mass for force balance operation, or self-test and self-calibration.

Abstract: A symmetrical differential capacitive sensor (60) includes a movable element (66) pivotable about a geometrically centered rotational axis (70). The element (66) includes sections (86, 88). Each of the sections (86, 88) has a stop (94, 96) spaced equally away from the rotational axis (70). Each of the sections (86, 88) also has a different configuration (104, 108) of apertures (102, 106). The configurations (104, 108) of apertures (102, 106) create a mass imbalance between the sections (86, 88) so that the element (66) pivots about the rotational axis (70) in response to acceleration. The apertures (102, 106) also facilitate etch release during manufacturing and reduce air damping when the element (66) rotates. Apertures (126, 128) are formed in electrodes (78, 80) underlying the apertures (102, 106) to match the capacitance between the two sections (86, 88) of movable element (86) to provide the same bi-directional actuation capability.

Abstract: An inertial sensor and a fabrication method of an inertial sensor are provided. An inertial sensor includes: an elastic support whose one end is supported by a support part disposed on a substrate; an oscillator which is supported by the other end of the elastic support as it is separated from the substrate; and a displacement detecting part which detects a displacement of the oscillator to output a signal, wherein the oscillator is formed with one or both of a groove and a through hole in a direction in parallel with a drive direction of the oscillator.

Abstract: A physical sensor includes: a substrate having a silicon layer, an oxide film and a support layer; and a sensor portion having movable and fixed electrodes and a lower electrode. The movable electrode is supported by a beam on the support layer. The fixed electrode faces the movable electrode. The lower electrode is disposed on the support layer and faces the movable electrode. The physical sensor detects horizontal physical quantity based on a capacitance between the movable and fixed electrodes, and vertical physical quantity based on a capacitance between the movable and lower electrodes. The beam includes vertical and horizontal beams. The thickness of the vertical beam is smaller than the thickness of the horizontal beam.

Abstract: Micromachined accelerometer having one or more proof masses (16, 36, 37, 71, 72) mounted on one or more decoupling frames (17, 38, 39) or on a shuttle (73) such that the proof mass(es) can move along a first (y) axis in response to acceleration along the first axis while being constrained against movement along a second (x) axis and for torsional movement about a third (z) axis perpendicular to the first and second axes in response to acceleration along the second axis. Electrodes (26, 53, 54, 78, 79) that move with the proof mass(es) are interleaved with stationary electrodes (27, 56, 57, 81, 82) to form capacitors (A-D) that change in capacitance both in response to movement of the proof mass(es) along the first axis and in response to torsional movement of the proof mass(es) about the third axis, and circuitry (31-34) connected to the electrodes for providing output signals corresponding to acceleration along the first and second axes.

Abstract: A micromachined sensor and a process for fabrication and vertical integration of a sensor and circuitry at wafer-level. The process entails processing a first wafer to incompletely define a sensing structure in a first surface thereof, processing a second wafer to define circuitry on a surface thereof, bonding the first and second wafers together, and then etching the first wafer to complete the sensing structure, including the release of a member relative to the second wafer. The first wafer is preferably a silicon-on-insulator (SOI) wafer, and the sensing structure preferably includes a member containing conductive and insulator layers of the SOI wafer. Sets of capacitively coupled elements are preferably formed from a first of the conductive layers to define a symmetric capacitive full-bridge structure.

Abstract: The present invention relates to measuring devices for use in physical measuring, and in particular to capacitive sensors. In the sensor according to the invention, the shape of the stationary electrode (3), (4), (12), (17-20), (27-28) is stepped. Through the invention, a method for manufacturing a capacitive sensor with improved linearity is achieved, as well as a capacitive sensor suitable for use particularly in small capacitive sensor solutions.

Abstract: A capacitive sensor includes an error compensating unit that, in an arrangement that a part of a fixed electrode as an edge portion and a part of a movable electrode as an edge portion are opposed to each other keeping a gap in a direction of shift of a detecting unit, reduces a detection error of capacitance due to the shift of comb-tooth portions from each other in the detecting unit, by a change of capacitance according to variation of the gap caused by the shift.

Abstract: An accelerometer uses variations in capacitance to detect and measure the movement of a moving mass in relation to a fixed part. The accelerometer comprises a first series of electrodes, which are solidly connected to the mass and which are interdigitated with a second series of electrodes. The second series of electrodes are solidly connected to the fixed part. The accelerometer further comprises an electronic circuit which: detects the variation in at least one capacitance between the moving mass and the fixed part, in the form of a moving mass displacement indicator; and also generates an electrostatic stress in order to return the moving mass to the initial position thereof.

Abstract: A displacement measurement apparatus for a microstructure according to the present invention measures a displacement of the microstructure having a fixed portion electrode including a first electrode and a second electrode and a movable portion electrode located oppositely to the fixed portion electrode. A bias generating circuit applies a bias signal to between the first electrode and the movable portion electrode so that influence of a noise signal on a detection signal picked up from between the second electrode and the movable portion electrode may be reduced. A C/V converting circuit converts a capacitance change that is picked up from between the second electrode and the movable portion electrode into a voltage. A detecting circuit detects a displacement of the movable portion electrode based on the voltage.

Abstract: Coulomb islands are charged to create Coulomb forces which are applied between a first and second substrate. The Coulomb islands are used to levitate the first substrate over the second substrate into an equilibrium position. A processing unit monitors the values of capacitors formed between the substrates to provide feedback information to maintain the first substrate in this equilibrium position. The first substrate can be an accelerometer that can be used to calculate the direction and magnitude of a deceleration. The processing unit sends the digital information to a bus coupled to a plurality of air bags. The digital information identifies the appropriate air bags that need to be enabled to minimize the impact of a crash. Vertical changes in acceleration can also be detected making this invention applicable for flight vehicles.

Abstract: Apparatus, methods, and systems for incorporating and reading a plurality of bridge sensors is disclosed. The bridge sensors may be capacitive bridge sensors located on the same substrate with a digital processor and signal processing circuits to read the outputs of the sensors. The bridge sensors are accessed by a switch network coupled to the plurality of bridge sensors to selectively provide an output from at least one of the plurality of bridge sensors. The switch network may be a multiplexer, which provides a periodically oscillating voltage to the sensors, to energize the sensors. The multiplexer may also provide output from the energized sensor to the digital processor.

Abstract: Apparatus, methods, and systems for sensing acceleration and magnetic fields in all three axes from a first capacitive bridge sensor having a first proof mass; and a second capacitive bridge sensor having a second proof mass located within the first proof mass. The second proof mass is coupled to the first proof mass by springs that permit movement in the second axis. The of sense the remaining axis of interest may be done by a third and fourth capacitive bridge configured similar to that of the first and second capacitive bridge sensors. The third and fourth capacitive bridge sensors may be oriented 90 degrees off of the first and second capacitive bridge. An alternative is to locate a third capacitive bridge within the second proof mass.

Abstract: A 3-dimensional MEMS accelerometer fabricated on a single planar substrate deploys three co-planar sensor elements. Each sensor element is a capacitive device deploying a static electrode plate and a parallel dynamic electrode plate supported by a torsion beam. The dynamic electrode plate also includes a proof mass portion that displaces the center of gravity to below the plane of the plate. Two of the sensor elements are identical and rotated by 90 degrees on the planar substrate. The third capacitive sensor has two pairs of adjacent capacitive plates, each one having a dynamic electrode plate is suspended by a torsion beam. The proof mass on each dynamic electrode plates however is offset laterally from the torsion axis in opposite directions from the other plates to cancel the their respective capacitance charges induced by in-plane acceleration. However, this arrangement also adds the capacitive change induced by acceleration orthogonal to the planar substrate.

Abstract: A method for manufacturing a physical quantity sensor having a movable portion, a support portion and an optical part is provided. The method includes steps of: etching a silicon substrate so that a movable-portion-to-be-formed portion, a support-portion-to-be-formed portion, and an optical-part-to-be-formed portion having a plurality of columns and trenches are formed; oxidizing the optical-part-to-be-formed portion so that each column changes to a silicon oxide column and the trench is filled with a silicon oxide layer; and removing a part of the movable-portion-to-be-formed portion connecting to the silicon substrate so that the movable portion is separated from the silicon substrate.

Abstract: A detector device includes a drive circuit for outputting a drive pulse signal for displacing the variable block, a detection pulse signal applying unit by which the variable capacitance elements and the fixed capacitance element whose one end is connected in common are respectively applied, at their other ends, with detection pulse signals with a plurality of phases each having a predetermined phase difference at a timing synchronized with the drive pulse signal, and an inertia detection unit for detecting a difference in capacitance value between the variable capacitance elements to which the detection pulse signal having the phase difference is applied, or between the fixed capacitance element and the variable capacitance element, and detecting the applied inertial force based on the difference.

Abstract: Techniques capable of suppressing fixation between a movable electrode and a fixed electrode in an inertial sensor and preventing the inertial sensor from malfunctioning are provided. The movable electrode, the fixed electrode provided so as to face the movable electrode, a peripheral conductor facing both the movable electrode and the fixed electrode, and a demodulation circuit and a voltage adjustment circuit which adjust the electric potential of the peripheral conductor so that the electric potential of the peripheral conductor becomes the same as the electric potential of the movable electrode are provided, and a change in the capacitance between the movable electrode and the fixed electrode is detected.

Abstract: In an electrostatic-capacitance-type acceleration sensor, water, etc. penetrating into a sealed space incorporating an acceleration detector having a movable electrode 6, and sticking of the movable electrode 6 to a cap 8 due to static charge accumulated on the cap 8 during the anodic bonding being performed are prevented. A conductive shielding film 9 that can be extendedly transformed on the entire inner face of the cap 8 constituting the sealed space is provided, which is not only extendedly arranged so as to be sandwiched between a bonding frame 7 and the cap 8, but also electrically connected to the movable electrode 6; thereby, even if unevenness exists on the surface of the bonding frame 7, not only sufficient anodic bonding between the bonding frame 7 and the cap 8 becomes possible, but also the electric field due to the static charge accumulated in the cap 8 can be shielded.

Abstract: A sensor that measures angular velocity about an axis that is normal to a sensing plane of the sensor. The sensor comprises a sensing subassembly that includes a planar frame parallel to the sensing plane, a first proof mass disposed in the sensing plane, a second proof mass disposed in the sensing plane laterally to the first proof mass, and a linkage within the frame and connected to the frame. The linkage is connected to the first proof mass and to the second proof mass. The sensor further includes actuator for driving the first proof mass and the second proof mass into oscillation along a drive axis in the sensing plane. The sensor further includes a first transducer to sense motion of the frame in response to a Coriolis force acting on the oscillating first proof mass and the oscillating second proof mass.

Abstract: A diaphragm (14) is formed using MEMS technology. The diaphragm (14) has a hinge structure, and at least one of a hinge upper corner portion and a hinge lower corner portion of the diaphragm (14) is rounded.

Abstract: A semiconductor device according to the present invention includes a semiconductor substrate and an MEMS sensor provided on the semiconductor substrate.

Abstract: A pendulous capacitive accelerometer including a substrate having a substantially planar upper surface with an electrode section, and a sensing plate having a central anchor portion supported on the upper surface of the substrate to define a hinge axis. The sensing plate includes a solid proof mass on a first side of the central anchor portion and a substantially hollow proof mass on a second side of the central anchor portion, providing for reduced overall chip size and balanced gas damping. The solid proof mass has a first lower surface with a first electrode element thereon, and the substantially hollow proof mass has a second lower surface with a second electrode element thereon. Both the solid proof mass and the hollow proof mass have the same capacitive sensing area. The sensing plate rotates about the hinge axis relative to the upper surface of the substrate in response to an acceleration.

Abstract: An angular velocity sensor includes first and second vibrators having a movable portion with driving and detecting purpose movable electrodes and a fixed portion with first and second side driving and detecting purpose fixed electrodes. The driving voltages applied to the first side driving purpose fixed electrode in the first vibrator is a first driving voltage including direct and alternating voltages. The driving voltage applied to the second side driving purpose fixed electrode in the first vibrator is a second driving voltage including direct and alternating voltages. At least one of the direct voltages, one of the alternating voltages, or one of duty ratios of the first and second driving voltages is controlled so that the first vibrator vibrates opposite to the second vibrator.

Abstract: A capacitive sensor for detecting a physical quantity includes a sensor element and a detecting circuit. The sensor element includes a movable electrode and a fixed electrode. A periodic voltage is applied to the fixed electrode. A high-voltage generating circuit applies a diagnostic voltage to an input side of a C-V conversion circuit so as to diagnose a sticking of a foreign object between the movable electrode and the fixed electrode. The C-V conversion circuit includes a diagnostic switch, which is opened in a diagnostic mode. The periodic voltage in the diagnostic mode is larger than the periodic voltage in a normal measuring mode.

Abstract: An acceleration sensor having a mass which is movably supported outside its center of gravity, first electrodes on the mass and second electrodes located at a distance therefrom forming a capacitive sensor in order to determine a change in position of the mass as a function of time. At least one spring element which generates a restoring force when the mass is deflected from its neutral position is provided on the side of the mass facing the capacitive sensor. The mass may be obtained by being exposed from a material layer, and the mass is surrounded, at least at its side faces, by this material.

Abstract: A physical quantity sensor has a weight mass movable in a detection direction. Auxiliary capacitors are formed at both side ends of the weight mass in a non-detection direction by auxiliary movable electrodes and auxiliary fixed electrodes, respectively. When capacitances of the auxiliary capacitors change due to movement of the weight mass in the non-detection direction, a limiter circuit feedback-controls voltages applied to the auxiliary fixed electrodes to maintain the position of the weight mass unchanged. Thus, the weight mass is limited from moving in the non-detection direction thereby to improve accuracy in detection of the movement in the detection direction.

Abstract: In a micro-electromechanical structure of semiconductor material, a detection structure is formed by a stator and by a rotor, which are mobile with respect to one another in presence of an external stress and are subject to thermal stress; a compensation structure of a micro-electromechanical type, subject to thermal stress and invariant with respect to the external stress, is connected to the detection structure thereby the micro-electromechanical structure supplies an output signal correlated to the external stress and compensated in temperature.

Abstract: Accelerometers and associated techniques for detecting motion are described. For a resonant accelerometer, an externally-applied acceleration can cause a change in the electrical spring constant Kc of the electromechanical system. A resonant accelerometer can be driven to resonate in a bulk acoustic wave mode of vibration, which can have a high resonant frequency. Other accelerometers and associated techniques are disclosed.

Abstract: A capacitive detector that accurately detects a physical quantity with a simple circuitry. An acceleration sensor includes a capacitance converter, an amplifier, a detection element unit, and a signal controller. The capacitor converter, which includes an operational amplifier, a switch, and a capacitor, converts a change in differential capacitance, which is obtained by fixed electrodes and a movable electrode, to voltage. The operational amplifier has a non-inversion input terminal, which receives a reference voltage. The signal controller supplies voltage that is applied to the fixed electrodes of the detection element unit. The signal controller includes a bias supply unit, which applies a predetermined bias voltage to the fixed electrodes during a test mode.

Abstract: A semiconductor device according to the present invention includes a semiconductor substrate and an MEMS sensor provided on the semiconductor substrate. The MEMS sensor includes a vibratory first electrode and a plurality of second electrodes opposed to the first electrode at an interval.

Abstract: A microelectromechanical system (MEMS) device with a mechanism layer having a first part and a second part, and at least one cover for sealing the mechanism layer. The inner surface of at least one of the covers is structured such that a protruding structure is present on the inner surface of the cover and wherein the protruding structure mechanically causes the first part to be deflected out of a plane associated with the second part.

Abstract: The present invention provides a micromachined sensor. The micromachined sensor includes a proof mass movable with respect to a substrate. The proof mass includes a first portion, a second portion separated from the first portion and a third portion connecting the first portion to the second portion. A frame is positioned on the substrate and encloses the proof mass. A plurality of springs connects the proof mass to the frame. A plurality of first and second electrodes extends from the frame. A plurality of third electrodes extends from the first portion of the proof mass and is interleaved with the first electrodes. A plurality of fourth electrodes extends from the second portion of the proof mass and is interleaved with the second electrodes. A first support beam extends from the frame to the area between the first and second portions of the proof mass. A plurality of seventh and eighth electrodes extends from the first support beam.

Abstract: In the manufacturing technology of an integrated MEMS in which a semiconductor integrated circuit (CMOS or the like) and a micro machine are monolithically integrated on a semiconductor substrate, a technology capable of manufacturing the integrated MEMS without using a special process different from the normal manufacturing technology of a semiconductor integrated circuit is provided. A MEMS structure is formed together with an integrated circuit by using the CMOS integrated circuit process. For example, when forming an acceleration sensor, a structure composed of a movable mass, an elastic beam and a fixed beam is formed by using the CMOS interconnect technology. Thereafter, an interlayer dielectric and the like are etched by using the CMOS process to form a cavity. Then, fine holes used in the etching are sealed with a dielectric.

Abstract: A structure is presented in which it is easy to adjust, to a determined value, distance between electrodes of a condenser formed in an electrostatic capacity-type displacement sensor. A displacement sensor has a conductive lower layer, an insulating layer stacked on the conductive lower layer and a conductive upper layer stacked on the insulating layer. The conductive lower layer is divided into a first lower region and a second lower region by a groove penetrating the conductive lower layer. The insulating layer is stacked on the conductive lower layer at selected portions. The conductive upper layer is stacked on the insulating layer at selected portions. The conductive upper layer has a beam connected via the insulating layer to the first lower region and the second lower region at a pair of ends of the beam. The conductive upper layer has a first upper portion forming one of electrodes of a first condenser.

Abstract: There is provided a bidirectional readout circuit for detecting direction and amplitude of an oscillation sensed at a capacitive microelectromechanical system (MEMS) accelerometer, the bidirectional readout circuit converting capacitance changes of the capacitive MEMS accelerometer into a time change amount by using high resolution capacitance-to-time conversion technology and outputting the time change amount as the direction and the amplitude of the oscillation by using time-to-digital conversion (TDC) technology, thereby detecting not only the amplitude of the oscillation but also the direction thereof, which is capable of being applied to various MEMS sensors.

Abstract: In the manufacturing technology of an integrated MEMS in which a semiconductor integrated circuit (CMOS or the like) and a micro machine are monolithically integrated on a semiconductor substrate, a technology capable of manufacturing the integrated MEMS without using a special process different from the normal manufacturing technology of a semiconductor integrated circuit is provided. A MEMS structure is formed together with an integrated circuit by using the CMOS integrated circuit process. For example, when forming an acceleration sensor, a structure composed of a movable mass, an elastic beam and a fixed beam is formed by using the CMOS interconnect technology. Thereafter, an interlayer dielectric and the like are etched by using the CMOS process to form a cavity. Then, fine holes used in the etching are sealed with a dielectric.

Abstract: 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.

Abstract: A symmetrical differential capacitive sensor (60) includes a movable element (66) pivotable about a geometrically centered rotational axis (70). The element (66) includes sections (86, 88). Each of the sections (86, 88) has a stop (94, 96) spaced equally away from the rotational axis (70). Each of the sections (86, 88) also has a different configuration (104, 108) of apertures (102, 106). The configurations (104, 108) of apertures (102, 106) create a mass imbalance between the sections (86, 88) so that the element (66) pivots about the rotational axis (70) in response to acceleration. The apertures (102, 106) also facilitate etch release during manufacturing and reduce air damping when the element (66) rotates. Apertures (126, 128) are formed in electrodes (78, 80) underlying the apertures (102, 106) to match the capacitance between the two sections (86, 88) of movable element (86) to provide the same bi-directional actuation capability.

Abstract: Various systems and methods for sensing are provided. In one embodiment, a sensing system is provided that includes a first electrode array disposed on a proof mass, and a second electrode array disposed on a planar surface of a support structure. The proof mass is attached to the support structure via a compliant coupling such that the first electrode array is positioned substantially parallel to and faces the second electrode array, where the proof mass is capable of displacement relative to the support structure. The displacement of the proof mass is in a direction substantially parallel to the second electrode array. The first electrode array comprises a plurality of first patterns of electrodes, the first patterns being interdigitated, and each of the first patterns comprises at least two first electrodes. The second electrode array comprises a plurality of second patterns of electrodes, the second patterns being interdigitated.

Abstract: A capacitive transducer a first part containing a first set of capacitor plates and a second part relatively movable in a plane to the first part. The second part contains a second set of capacitor plates. Both sets of capacitor plates are built on a substrate, wherein the capacitor plates form a plurality of capacitors. The second part is relatively movable in all six degrees of freedom. One set of the plurality of capacitors measures displacements in a plane and a second set of the plurality capacitors measures displacements perpendicular to the plane.

Abstract: A capacitive acceleration sensor is provided in which sticking of a mass body, made of silicon, to a first sealing substrate or a second sealing substrate, made of glass, is prevented.

Abstract: A Micro-Electro-Mechanical System closed-loop (MEMS) inertial device having a vertical comb drive that exhibits improved performance under vibration. The device includes one or more stator tines extending from a housing into a cavity formed by the housing. One or more rotor tines extend from a proof mass located in the cavity. The proof mass is joined to the housing by flexures which allow movement in the vertical direction. The rotor tines have a first length value in the direction of movement and the stator tines have a second length value in the direction of movement. The second length value is greater than the first length value. Also, the stator tines include two electrically separated portions. The lesser length of the rotor tines relative to the stator tines causes the attractive force between the rotor tines and either the upper or lower half of the stator tines to be relatively independent of rotor vertical position. This, in turn, produces better accelerometer accuracy in vibration environments.

Abstract: A system and method in accordance with the present invention provides for a low cost, bulk micromachined accelerometer integrated with electronics. The accelerometer can also be integrated with rate sensors that operate in a vacuum environment. The quality factor of the resonances is suppressed by adding dampers. Acceleration sensing in each axis is achieved by separate structures where the motion of the proof mass affects the value of sense capacitors differentially. Two structures are used per axis to enable full bridge measurements to further reduce the mechanical noise, immunity to power supply changes and cross axis coupling. To reduce the sensitivity to packaging and temperature changes, each mechanical structure is anchored to a single anchor pillar bonded to the top cover.

Abstract: 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.

Abstract: 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.

Abstract: 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.