Abstract: The invention relates to a method for determining the angular position (theta) of a rotor (2) pertaining to an electric motor (1) and comprising a number of pairs of poles. Said method consists of the following steps: a pulse pattern (PM1,PM2,PM3) with a pulse duration (T) flows through at least one stator coil (7) of the electric motor (1), such that the rotor (2) does not rotate by more than 90 DEG, divided between the number of pairs of poles, during the pulse duration (T); the angular acceleration (alpha) of the rotor (2), caused by the pulse pattern flowing through the at least one stator coil, (7) is detected; and the angular position (theta) of the rotor (2) is determined by means of the correlation between the flow through the stator coil (7) and the angular acceleration (alpha) of the rotor (2).

Abstract: A detection circuit includes a detection terminal to which an alternating current signal from a physical quantity transducer is input, a detection current/voltage conversion amplifier circuit that converts the alternating current signal input through the detection terminal into a voltage signal, an evaluation terminal that supplies an evaluation voltage signal to the detection current/voltage conversion amplifier circuit, an input resistor that has a given resistance ratio with respect to a feedback resistor; and a switch circuit of the detection circuit provided in a signal path that connects the evaluation terminal and an input node of the detection current/voltage conversion amplifier circuit.

Abstract: A brain and/or skull impact measurement system has a body mounted impact device. The body mounted impact device includes a tri-axial accelerometer configured to measure impacts to an individual's body where the sensor produces impact data in response to the impact. A reader is provided with a data processor and a transmitter/receiver that receives the impact data. The reader is coupled to the body mounted impact device and can be a handheld device.

Abstract: 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.

Abstract: Single chip 3-axis thermal accelerometer devices include a substrate, at least one cavity etched in the substrate, a fluid disposed in the cavity, a bridge structure suspended over an opening of the cavity, and a plurality of heater elements and temperature sensing elements disposed on the bridge structure. The substrate has a substantially planar surface defined by X and Y coordinate axes, and the bridge structure is suspended over the opening of the cavity in the X-Y plane. In one embodiment, the bridge structure is configured to position at least two of the temperature sensing elements out of the X-Y plane. The heater and temperature sensing elements are disposed on the bridge structure in optimized arrangements for providing reduced temperature coefficients and for producing output voltages having reduced DC offset and drift.

Abstract: 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.

Abstract: An attitude detection sensor includes three magnetic sensing parts that detect magnetic field strength in respective directions along three axes perpendicular to each other, and two tilt sensing parts that detect tilt angles around two axes perpendicular to each other. The tilt sensing parts each include a cantilever having a magnet body that moves in accordance with the tilt angle, and a magnetic detection head that detects a displacement of the magnet body. The three magnetic sensing parts and the two magnetic detection heads are each formed using a magnetic detection element of the same type. At least one electronic circuit for controlling the five magnetic detection elements, the three magnetic sensing parts, and the two tilt sensing parts is disposed in a single package in the form of a module.

Abstract: Conventional accelerometers are based on test masses that are suspended in some kind of spring damper system. According to an exemplary embodiment of the present invention, a two-dimensional adaptive accelerometer based on dielectrophoresis is provided, which measures an acceleration of a test mass freely floating in a medium by determining the movement of the test mass due to an accelerating force acting on the test mass. A non-uniform electric force field provides for a wide and adjustable dynamic range.

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: Movement of a cellular telephone is detected by an acceleration sensor fixed on a housing (substrate), the cellular telephone and user's operations are detected by an acceleration sensor semifixed on the housing (substrate) via a flexible member, and the user's operations are detected on the basis of a difference between these detection results and a display process corresponding to the user's operations is executed.

Abstract: A three axes MEM accelerometer system includes three MEM accelerometer sensors and a MEM sensor board including a MEM sensor control circuit for the accelerometer sensors. The accelerometer sensors are mounted mutually orthogonally. At least two coplanar mounting members have a first surface coplanar with a connection pad on the surface of the sensor board. A second surface is inclined to the surface of the board for mounting a MEM accelerometer sensor. An electrical conductor array interconnects the MEM accelerometer sensor with the connection pad on the board.

Abstract: Methods and systems for forming accelerometers include forming a load beam supported at one end having an input interdigital transducer (IDT) and an output IDT. The load-beam has a cross section varying in the longitudinal direction effective to cause the load beam to deflect radially in response to an applied load. The cross section varies in width, height, or both.

Abstract: A released-beam sensor includes a semiconductor substrate having a layer formed thereon, and an aperture formed in the layer. A beam is mechanically coupled at a first end to the layer and suspended above the layer such that a second end forms a cantilever above the aperture. A boss is coupled to a second end of the beam and suspended at least partially within the aperture. The beam is configured to flex in response to acceleration of the substrate along a vector substantially perpendicular to a surface of the substrate. Parameters of the sensor, such as the dimensions of the beam, the mass of the boss, and the distance between the boss and a contact surface within the aperture, are selected to establish an acceleration threshold at which the boss will make contact with the contact surface. The sensor may be employed to deploy an airbag in a vehicle.

Abstract: A semiconductor physical quantity sensor includes: a substrate; a semiconductor layer supported on the substrate; a trench disposed in the semiconductor layer; and a movable portion disposed in the semiconductor layer and separated from the substrate by the trench. The movable portion includes a plurality of through-holes, each of which penetrates the semiconductor layer in a thickness direction. The movable portion is capable of displacing on the basis of a physical quantity applied to the movable portion so that the physical quantity is detected by a displacement of the movable portion. The movable portion has a junction disposed among the through-holes. The junction has a trifurcate shape.

Abstract: An inertial sensor is provided which includes a self-diagnosis circuit which applies an AC-bias signal voltage ahead of a synchronous demodulator, and thereby, supplies a diagnostic signal for detecting an abnormality in at least one of a detecting element and a detection circuit. This inertial sensor is capable of actively diagnosing whether or not there is an abnormality in the sensor itself, only by monitoring whether a predetermined DC offset signal is obtained from a sensor output terminal of the inertial sensor.

Abstract: An acceleration sensor in accordance with an aspect of the present invention comprises a first substrate, a multilayer second substrate and a sensor portion. The multilayer second substrate is opposed to the first substrate. The multilayer second substrate is provided with an electrode drawing opening. Further, the multilayer second substrate consists of a plurality of layers. The sensor portion (a movable mass body and a fixed electrode) is provided in a sealed cavity portion which is formed between the first substrate and the multilayer second substrate which are opposed to each other.

Abstract: A jerking-initiated switch includes two first shank members and two second shank members secured to first and second lateral sides of a base wall of an insulating frame to define a rolling path for rolling of an electrically conductive ball therealong. Two limb members are respectively and integrally formed with, and extend from, the second shank members to form a guideway along the rolling path such that the ball can slidably contact the limb members, and extend towards the first shank members to terminate at threshold regions that are spaced apart from the first shank members. The limb members have idle regions on the rolling path. Once the ball is jerked to displace from one of the idle and threshold regions to the other, the switch is placed in one of the first and second switching states.

Abstract: A semiconductor acceleration sensor of the invention comprises: a sensor chip having a pad formation surface around whose edge are formed a plurality of pads, and in which a rectangular frame shaped protrusion is formed on an area of the pad formation surface on a center side of the pads; and a control chip which has a terminal formation surface on which connection terminals are formed, and has a planar shape such that the pad of the sensor chip is visible from the terminal formation surface side. Moreover, the opposite surface of the control chip to the terminal formation surface is bonded to the frame shaped protrusion of the sensor chip.

Abstract: A method of measuring acceleration includes suspending an inertial body using a magnetic fluid; generating a magnetic field within the magnetic fluid; modulating the magnetic field to counteract a change in position of the inertial body relative to sources of the magnetic field due to acceleration; and calculating the acceleration based on the modulation. The calculating step derives the acceleration based on an amount of current through drive coils required for the modulation. The acceleration includes linear acceleration and/or angular acceleration. The drive coils include permanent magnets, electromagnets, or a combination of a permanent magnet and an electromagnet. Sensing coils can be used for detecting the displacement of the inertial body. Each sensing coil can be positioned substantially within a corresponding drive coil. The inertial body can be non-magnetic, weakly magnetic, or have a ferromagnetic coating.

Abstract: An oscillator is oscillatable in a predetermined direction. First and second driving electrodes are secured to the base and apply an electrostatic force to the oscillator to make drive oscillation of the oscillator in the predetermined direction. At the time of the drive oscillation of the oscillator, a predetermined electric charge is accumulated in the oscillator, and electric charges of opposite polarities are alternately and periodically accumulated in the first and second driving electrodes, respectively, to exert an attractive force between the oscillator and a corresponding one of the first and second driving electrodes and also to exert a repulsive force between the oscillator and the other one of the first and second driving electrodes, and vice versa.

Abstract: An acceleration sensor includes a semiconductor substrate, a sensing element formed on the semiconductor substrate, a bonding frame made of polysilicon which is formed on the semiconductor substrate and surrounds the sensing element, and a glass cap which is bonded to a top surface of the bonding frame made of polysilicon to cover the sensing element above the sensing element while being spaced by a predetermined distance from the sensing element. The bonding frame made of polysilicon is not doped with any impurity.

Abstract: A rotation angle detector includes a rotator, a detecting rotator, a magnet, an anisotropic magnetoresistive element, an amplifier, and a controller. The controller connects an output terminal of the anisotropic magnetoresistive element to the ground so as to detect a short circuit between adjacent output terminals based on the difference in output voltage from the amplifier. When there is no short circuit, the controller releases the connection from the output terminal to the ground, and detects the rotation angle of the rotator from the output signal that is differentially amplified by the amplifier based on the output signal of the anisotropic magnetoresistive element.

Abstract: Position sensing of movable elements including but not limited to machine components is disclosed. Motion of a movable element can produce motion of a magnetic field, which can be detected by magnetic sensors. The motion and/or variations of a magnetic field and/or a magnetic flux may be produced by any combination of a motion of the sensors, associated magnets, or associated magnetic material. Magnetic sensors maybe capable of measuring either rotary, or linear motion, or both. Such sensors can provide indication of an incremental position change, an absolute position, or both. Absolute position and high-resolution position sensing may be produced for measurement of either linear and/or angular motion. Suitable magnetic sensors include, but are not limited to, Hall effect devices and/or magneto-resistive elements, and may include multi-element magnetic sensors. Suitable signal conditioning and/or control means such as control electronics can be used to receive output signals from the sensors.

Abstract: A monolithic integrated 3-axis accelerometer chip includes a single crystal substrate, the substrate including at least one single crystal membrane layer portion. A single sensor microstructure made from the single crystal membrane senses acceleration in each of the three orthogonal directions. At least one electronic circuit can also be disposed on the chip, such as a circuit for driving, detecting, controlling and signal processing.

Abstract: An acceleration sensor includes at least one permanent magnet, a spring member for supporting the at least one permanent magnet to displace the at least one permanent magnet when an external force is applied, and a magnetic field detection sensor mounted in stationary state to face the at least one permanent magnet. The magnetic field detection sensor has at least one multi-layered MR element that includes a magnetization fixed layer and a magnetization free layer. The magnetization fixed layer is magnetized in a direction parallel to a displacement detection direction. Each permanent magnet has a multi-layered structure of hard magnetic material layers and nonmagnetic material layers alternately laminated each other in a direction perpendicular to a plane of the magnetic field detection sensor and to the magnetized direction of the magnetization fixed layer.

Abstract: According to the present invention, a method for fabricating a three-dimensional acceleration sensor, comprising: providing a semiconductor substrate having first and second surfaces; forming an insulating layer on the first surface of the semiconductor substrate; forming an active layer on the insulating layer; forming a plurality of openings on the active layer at a first region, which is to be located above a movable mass with a predetermined space; selectively removing the insulating layer located under the first region in a wet-etching process through the plurality of openings; and selectively removing the active layer to form a groove separating the first region from a movable mass.

Abstract: An angular rate sensor includes: a circuit board; a package including an angular rate sensor chip and a connection terminal; and a conductive member. The angular rate sensor chip is accommodated in the package. The package is disposed on the circuit board through the conductive member. The package further includes a first electrode disposed on a bottom of the package, the first electrode connecting to the connection terminal. The circuit board includes a second electrode disposed on a top of the circuit board. The angular rate sensor chip in the package is electrically connected to the circuit board through the connection terminal, the first and the second electrodes and the conductive member. The circuit board and the package are electrically and elastically connected by the conductive member.

Abstract: The inventive device for evaluating the sensor signal includes the provider for providing the sensor signal, the processor for processing the sensor signal and for providing an information signal comprising information regarding the amplitude course of the sensor signal and means for comparing the sensor signal to a first and a second comparison value, wherein the first and/or the second comparison value are adjustable based on the information signal such that a difference between the first and the second comparison value comprises a non-linear relation to the amplitude course of the sensor signal.

Abstract: A method for assembling a speed-sensing device for monitoring an angular velocity of a rotatable shaft, comprises the steps of: providing a hollow housing having a speed sensor hole, installing a stopper plug into the speed sensor hole so that a stein portion of the stopper plugs extends into the housing, inserting a tone wheel into the housing and inserting the shaft into the housing until the shaft positively engages the tone wheel. The speed-sensing device comprises the tone wheel non-rotatably mounted to the shaft. The shaft has a shaft groove formed on an outer peripheral surface thereof, while the tone wheel has a wheel groove formed on an inner peripheral surface thereof. The speed-sensing device further includes a snap ring retainer provided to engage the complementary shaft and wheel grooves in order to prevent movement of the tone wheel along the shaft.

Abstract: A three-axis acceleration sensor having a simple construction is provided for improving shock resistance without lowering sensor sensitivity. An acceleration sensor for detecting acceleration in three orthogonal directions comprises an electrode substrate pair including electrode substrates (4) opposed to each other, and each having fixed electrodes (4c, 4b, 4a) corresponding to three axes, respectively, a diaphragm (2) acting as a movable electrode, and an umbrella-like weight (3) mounted centrally of the diaphragm (2). Acceleration is detected based on variations in capacitance between the fixed electrodes (4c, 4b, 4a) and diaphragm (2). Each electrode substrate (4) has an electret layer (1) formed to cover surfaces of the fixed electrodes (4c, 4b, 4a). At least one of the electrode substrates defines, centrally thereof, a through hole (7). A shaft portion of the umbrella-like weight (3) extends through the through hole (7) from outside, and is connected to the diaphragm (2).

Abstract: A MEMS device and method of manufacturing comprises a magnetic sensor attached to a frame; at least one magnet adjacent to the magnetic sensor; a proof mass attached to the magnet; a cantilever beam attached to the proof mass; and a rod attached to the cantilever beam and the frame, wherein the magnet is adapted to rotate about a longitudinal axis of the rod. The proof mass comprises a portion of a SOI wafer. An acceleration of the frame causes the magnet to move relative to the frame and the magnetic sensor. An acceleration of the frame causes the connecting member to bend. The motion of the magnet causes a change in a magnetic field at a position of the magnetic sensor, wherein the change in the magnetic field is detected by the magnetic sensor, and wherein a sensitivity of detection of the acceleration of the device is approximately 0.0001 g.

Abstract: A semiconductor physical quantity sensor includes: a substrate; a semiconductor layer supported on the substrate; a trench disposed in the semiconductor layer; and a movable portion disposed in the semiconductor layer and separated from the substrate by the trench. The movable portion includes a plurality of through-holes, each of which penetrates the semiconductor layer in a thickness direction. The movable portion is capable of displacing on the basis of a physical quantity applied to the movable portion so that the physical quantity is detected by a displacement of the movable portion. The movable portion has a junction disposed among the through-holes. The junction has a trifurcate shape.

Abstract: A multi-directional shock sensor having a central post surrounded by an omnidirectionally moveable toroidal mass. A plurality of anchor members surrounds the mass and carries one arm of a latching arm assembly. The other arm of each latching arm assembly is carried by, and radially extends from the mass to oppose a respective first arm. A shock event will cause the mass to move in a certain direction to an extent where one or more of the arm assemblies will latch. The latching may be determined by an electrical circuit connected to contact pads on the central post and on the anchor members.

Abstract: A sensor apparatus (104) includes a plural different spatial direction axis of sensitivity positioned sensor package containing sensor module (305) supported by a planar surface (345) within a cavity (340) of a housing (205) coupled to a first end cap (210) by a PC-board connection (355). Housing (205) is further coupled to first end cap (210) by a first coupling member (315) and a second coupling member (320) and is also coupled to an opposite second end cap (215) by a third coupling member (320) and a fourth coupling member (325). Interface sealing members (330a, 330b, 330c, 330d) seal between housing (205) and first end cap (210). Interface sealing members (335a, 335b, 335c, 335d) seal between housing (205) and second end cap (215).

Abstract: Rotation detecting apparatus for detecting rotation of a magnetic rotor includes: a sensor chip having a magnetoresistive device; and a bias magnet. The magnetoresistive device is capable of detecting change of a magnetic vector near the sensor chip so that the rotation detecting apparatus detects the rotation of the magnetic rotor. The change of the magnetic vector is generated by the bias magnetic field and the rotation of the magnetic rotor. The bias magnet is disposed around the sensor chip so that a deflection angle of the magnetic vector is controllable.

Abstract: A magnetic infrasound sensor is produced by constraining a permanent magnet inside a magnetic potential well above the surface of superconducting material. The magnetic infrasound sensor measures the position or movement of the permanent magnet within the magnetic potential well, and interprets the measurements. Infrasound sources can be located and characterized by combining the measurements from one or more infrasound sensors. The magnetic infrasound sensor can be tuned to match infrasound source types, resulting in better signal-to-noise ratio. The present invention can operate in frequency modulation mode to improve sensitivity and signal-to-noise ratio. In an alternate construction, the superconductor can be levitated over a magnet or magnets. The system can also be driven, so that time resolved perturbations are sensed, resulting in a frequency modulation version with improved sensitivity and signal-to-noise ratio.

Abstract: A compact, high-sensitivity acceleration sensor that is prevented from being affected by factors other than acceleration, such as a change in temperature, has a bimorph acceleration-sensor element including first and second resonators attached to opposite sides of a base plate with respect to a direction in which acceleration is applied. One longitudinal end of the acceleration-sensor element is fixed such that the first and second resonators bend in the same direction in response to the acceleration. Changes in frequency or changes in impedance in the first and second resonators caused by the bending of the acceleration-sensor element are differentially detected in order to detect the acceleration. The acceleration-sensor element is bendable about a central bending plane in response to the acceleration, the central bending plane being positioned at a central portion of the base plate with respect to the application direction of acceleration.

Abstract: The thermal accelerometer of the invention comprises an enclosure having disposed therein a central filament powered by alternating electric current of zero mean amplitude and having a frequency lying between first and second resonant modes of vibration of the central filament, the central filament lying between detector filaments adjacent to reaction filaments powered by alternating electric current of zero mean amplitude and having a frequency lying between the first and second resonant modes of vibration of the reaction filaments.

Abstract: A system including a user input device for controlling a position of medical equipment is described. In an example embodiment, the user input device is configured to be coupled to the medical equipment and is responsive to an operator input representation of a desired movement of the equipment. A processor determines a direction in which the operator desires the equipment to move based on a device output.

Abstract: A motorcycle mileage counter inductor is constructed to include a magnetic device holder mounted in the outer end of the tubular color of the wheel set of a motorcycle's front wheel, an annular magnetic device mounted on the magnetic device holder, the annular magnetic device having a plurality of magnets alternatively abutted against one another in reversed directions, and a sensor formed of a Hall chip and mounted in a cover shell being affixed to the front fork of the motorcycle around the outer end of the tubular collar and electrically connected to the mileage counter and ABS (anti-locking brake system) of the motorcycle through a signal line for detecting the amount of rotation of the motorcycle's front wheel and providing a signal indicative of the amount of rotation of the motorcycle's front wheel to the mileage counter and ABS of the motorcycle.

Abstract: An accelerometer (305) for measuring seismic data. The accelerometer (305) includes an integrated vent hole for use during a vacuum sealing process and a balanced metal pattern for reducing cap wafer bowing. The accelerometer (305) also includes a top cap press frame recess (405) and a bottom cap press frame recess (420) for isolating bonding pressures to specified regions of the accelerometer (305). The accelerometer (305) is vacuum-sealed and includes a balanced metal pattern (730) to prevent degradation of the performance of the accelerometer (305). A dicing process is performed on the accelerometer (305) to isolate the electrical leads of the accelerometer (305). The accelerometer (305) further includes overshock protection bumpers (720) and patterned metal electrodes to reduce stiction during the operation of the accelerometer (305).

Abstract: A system and method for compensating for gradients in a dual cavity device such as but not limited to an accelerometer. A first source drives a first cavity at least two different modes, at least one mode varying with changes in cavity length. A second source drives a second cavity at least two different modes, at least one mode varying with changes in cavity length. A processor determines changes in cavity length as a function of both modes in both cavities to compensate for non-uniform behavior between the cavities.

Abstract: A device for acceleration measurement, in which measuring signals from a two-dimensional sensor from measuring different directions are combined (gated) with one another and then jointly evaluated in an evaluation circuit. This evaluation is carried out, for example, using a threshold-value discriminator, in order to perform a plausibility check for a crash detection.

Abstract: A sensor arrangement for measuring a displacement of a proof mass using a tunneling current includes a proof mass body suspended by micro-mechanical beams to permit a mass body movement, at least one integrated electrode tip arranged to be integrated with the proof mass body, and at least one external electrode tip arranged externally to the proof mass body and suspended by micro-mechanical beams to permit an external electrode movement, the at least one external electrode tip further arranged to be in a close proximity to the at least one integrated electrode tip to permit a flow of the tunneling current between the at least one external electrode tip and the at least one integrated electrode tip, in which the displacement of the proof mass causes a change in the tunneling current.

Abstract: A sensor arrangement for measuring a displacement of a proof mass using a tunneling current includes a proof mass body suspended by micro-mechanical beams to permit a mass body movement, at least one integrated electrode tip arranged to be integrated with the proof mass body, and at least one external electrode tip arranged externally to the proof mass body and suspended by micro-mechanical beams to permit an external electrode movement, the at least one external electrode tip further arranged to be in a close proximity to the at least one integrated electrode tip to permit a flow of the tunneling current between the at least one external electrode tip and the at least one integrated electrode tip, in which the displacement of the proof mass causes a change in the tunneling current.

Abstract: A capacitance type dynamic quantity sensor device includes a sensor chip having movable electrodes and sensor-chip side fixed electrodes disposed to confront the movable electrodes in a substrate surface horizontal direction X and a circuit chip disposed to confront the sensor chip. The movable electrodes are joined to the substrate through spring portions having degrees of freedom in the substrate surface horizontal direction X and the substrate surface vertical direction Z, so that the movable electrodes are displaceable in both the directions X and Z. A circuit-chip side fixed electrode is equipped at the site corresponding to the movable electrodes. The sensor chip and the circuit chip are electrically connected to each other through bump electrodes.

Abstract: In a motion detector according to the Ferraris principle, an excitation element applies an inhomogeneous time-dependent alternating magnetic field to an induction element. A motion of the induction element induces in the induction element an eddy current with a temporal characteristic that depends both on the velocity and the acceleration. A sensor element measures the temporal characteristic of the eddy current and supplies the temporal characteristic to a signal processing circuit which determines at least one useful signal that is proportional to the velocity and acceleration, respectively.

Abstract: Electrical characteristics of a semiconductor acceleration sensor containing a switched capacitor filter (15) are tested while the semiconductor acceleration sensor (1, 30, 50, 70, 90) is vibrated to apply a predetermined acceleration to the semiconductor acceleration sensor (1, 30, 50, 70, 90). The vibration frequency is fixed to a low frequency (for example, 50 Hz) at which the acceleration can be stably applied, and the characteristic of LPF is varied to plural kinds by a signal from an external testing apparatus (2, 40, 60, 80, 95). A sensor signal is received under each of the plural filter characteristics, and if these are within a predetermined specific range, the semiconductor acceleration sensor (1, 30, 50, 70, 90) is judged to be normal.

Abstract: An acceleration sensor device with processing circuits constructed in an IC chip form is disclosed, and the IC chip and the acceleration sensor chip are integrated. The acceleration sensor device is constituted of an acceleration sensor chip constituted of elastic support arms, a mass portion and a thick frame, a regulation plate for restricting the movement of the mass portion, and a protection case. The regulation plate is an IC chip having a processing circuit for electrically processing detected signals from the acceleration sensor chip, the IC chip also used as the regulation plate is disposed at an upper portion of the acceleration sensor chip with a predetermined gap from the acceleration sensor chip and electrically connected to the acceleration sensor chip, and the IC chip and the protection case are electrically connected to each other.

Abstract: An acceleration sensor includes a piezoelectric element and a support member for supporting the piezoelectric element at both longitudinal ends thereof. The piezoelectric element includes a laminate having a plurality of piezoelectric layers. An intermediate piezoelectric layer is a dummy layer which generates no charge when acceleration is applied thereto. Each of the two outer piezoelectric layers includes four longitudinally aligned regions separated at two borders and one central border where stress is inverted when the acceleration is applied. The two outer piezoelectric layers are polarized in the direction of thickness of the piezoelectric element such that cells adjacent to each other in the longitudinal direction of the piezoelectric elements have opposite polarization directions and such that cells aligned with each other in the direction of thickness have the same polarization.