Abstract: According to one embodiment, a sensor includes a sensor part including first and second sensor elements, and a circuit part. The first sensor element includes a first supporter, a first movable part capable of vibrating, first and second electrodes. The first electrode outputs a first signal corresponding to a vibration of the first movable part. The second electrode outputs a second signal corresponding to the vibration of the first movable part. The second sensor element includes a second supporter, a second movable part capable of vibrating, third and fourth electrodes. The third electrode outputs a third signal corresponding to a vibration of the second movable part. The fourth electrode outputs a fourth signal corresponding to the vibration of the second movable part. The circuit part includes a calculator. The calculator outputs a differential operation result between first and second processing signals.

Abstract: A rotation position detection device includes a change drum, a magnetic field generator, and a magnetic field detector. The magnetic field generator is fixed to the change drum and rotates along with the change drum to differentiate an ambient magnetic field. The magnetic field detector is formed separately from the magnetic field generator and fixed to a position at which a magnetic field changes in response to rotation of the magnetic field generator so as to detect the magnetic field and output a signal that depends on the rotational position of the change drum on the basis of the detection result.

Abstract: An angular rate sensor has a ring, a plurality of sensor-drivers, circuitry, a controller, an energy sensor, and an output signal generator. The sensors-drivers may be capacitors, inductors, or a sensor having a piezoelectric material. The sensor-drivers each have a component that vibrates along with the ring, and the sensor-drivers are arranged in cooperating sets, each cooperating set having two sensor-drivers positioned 180° apart. The circuitry can selectively engage some of the cooperating sets as sensors and others of the cooperating sets as drivers. Those sets used as sensors sense motion of the ring. Those sets used as drivers apply forces to the ring. Some of the drivers cause the ring to vibrate at its natural frequency, and some of the drivers seek to inhibit motion of the ring at particular locations. Locations at which drivers seek to inhibit motion are those locations that would be nodes in the absence of angular motion.

Abstract: A phononic travelling wave gyroscope. The gyroscope includes a phononic waveguide including at least one loop. The phase change incurred by phonons propagating around the loop is compared to a reference phase, and utilized to form an estimate of the rotational rate of the gyroscope.

Abstract: For ascertaining at least one variable regarding a state of a brake fluid in a brake system of a vehicle, an evaluation unit is configured to determine the at least one variable by taking into account at least one pair of values of a provided or ascertained volume flow variable regarding a volume flow of at least a portion of the brake fluid through a flow resistance in the brake system and a provided or ascertained associated pressure drop variable regarding a pressure drop at the flow resistance through which the volume flow flows. For the at least one pair of values taken into account, a volume flow variable lies within a first specified limited value range and the pressure drop variable lies within a second specified limited value range.

Abstract: One embodiment of the invention includes a CVG system. A plurality of electrodes electrostatically force a resonator into a periodic motion based on a drive axis forcer signal applied to a first set of the plurality of electrodes and a sense axis force-rebalance signal applied to a second set of the plurality of electrodes, and provides a sense axis pickoff signal and a drive axis pickoff signal. A gyroscope controller generates the drive axis forcer signal based on the drive axis pickoff signal and calculates an angular rate of rotation about an input axis based on the sense axis force-rebalance signal. The gyroscope controller modulates a predetermined disturbance signal component onto the sense axis force-rebalance signal and to control a modulation phase of the sense axis force-rebalance signal based on detection of the predetermined disturbance signal component in the sense axis force-rebalance signal to substantially mitigate bias and scale-factor error.

Abstract: Micromachined gyroscopes, such as those based upon microelectromechanical systems (MEMS) have the potential to dominate the rate-sensor market mainly due to their small size, low power and low cost. As MEMS gyroscopes are resonant devices requiring active excitation it would be beneficial to improve the resonator Q-factor reducing the electrical drive power requirements for the excitation circuitry. Further, many prior art MEMS gyroscope designs have multiple resonances arising from design and manufacturing considerations which require additional frequency tuning and control circuitry together with the excitation/sense circuitry. It would therefore be beneficial to enhance the bandwidth of the resonators to remove the requirement for such circuitry. Further, to address the relatively large dimensions of MEMS gyroscopes it would be beneficial for the MEMS gyroscopes to be fabricated directly above the CMOS electronics thereby reducing the die dimensions and lowering per die cost.

Abstract: In an angle detection method with a resolver, the method being for detecting a rotational angle of a rotator by synchronously detecting a first signal and a second signal that are two phase sine wave modulation signals obtained from a one phase excitation/two phase output resolver, the method includes: a first signal detection process which detects a signal in the order of the first signal and the second signal; and a second signal detection process which detects a signal in the order of the second signal and the first signal.

Abstract: A vacuum sealed directional microphone and methods for fabricating said vacuum sealed directional microphone. A vacuum sealed directional microphone includes a rocking structure coupled to two vacuum sealed diaphragms which are responsible for collecting incoming sound and deforming under sound pressure. The rocking structure's resistance to bending aids in reducing the deflection of each diaphragm under large atmospheric pressure. Furthermore, the rocking structure exhibits little resistance about its pivot thereby enabling it to freely rotate in response to small pressure gradients characteristic of sound. The backside cavities of such a device can be fabricated without the use of the deep reactive ion etch step thereby allowing such a microphone to be fabricated with a CMOS compatible process.

Abstract: A method is provided for determining a number of revolutions per minute (RPM) of a rotating object. The method includes transmitting interrogation signals at a regular period from a fixed antenna positioned adjacent to the rotating object. The method also includes transmitting echo signals from a sensor antenna positioned on the rotating object, in response to the interrogation signals. The method also includes counting a number of echo signals detected by the fixed antenna, during one revolution of the object. The method also includes determining the RPM of the rotating object based on the number of response signals and the regular period of the signals. A system is also provided for determining the number of revolutions per minute (RPM) of the rotating object.

Abstract: A micromechanical rotation rate sensor, in particular for use in motor vehicles, includes a substrate, at least one seismic mass, which is arranged in a sprung manner on the substrate, drive means for production of a periodic movement of the seismic mass, force detection means for detection of a Coriolis force, which acts on the seismic mass as a result of rotation about a rotation axis which is at right angles to the excitation direction, and measurement means, wherein the measurement means are designed for measurement of structural deviations of the rotation rate sensor.

Abstract: Provided is a gyroscope using a surface acoustic wave (SAW) and an angular velocity measurement method. The gyroscope includes an SAW resonator generating a first SAW, generating Coriolis force using an interaction between a velocity component of the first SAW and applied angular velocity on a metallic dot layer disposed in a certain position, and generating a second SAW using the Coriolis force, an SAW sensing oscillator generating a third SAW and receiving a fourth SAW, which is the third SAW reflected and returning after causing interference due to the second SAW, and a measurement device measuring a level of the applied angular velocity using variations in time of receiving the fourth SAW.

Abstract: A three-dimensional (3D) input sensing system includes a 3D input device, a host, and a power managing unit. The 3D input device includes at least one 3D motion sensing unit, and transmits a radio frequency (RF) signal obtained from detected motion of the 3D input device. The host receives the RF signal from the 3D input device and obtains 3D coordinate information of the 3D input device. The power managing unit controls supply of power in the 3D input device upon determining that the latter has remained motionless for a predetermined time period.

Abstract: An inertial sensing system comprises a first multi-axis atomic inertial sensor, a second multi-axis atomic inertial sensor, and an optical multiplexer optically coupled to the first and second multi-axis atomic inertial sensors. The optical multiplexer is configured to sequentially direct light along different axes of the first and second multi-axis atomic inertial sensors. A plurality of micro-electrical-mechanical systems (MEMS) inertial sensors is in operative communication with the first and second multi-axis atomic inertial sensors. Output signals from the first and second multi-axis atomic inertial sensors aid in correcting errors produced by the MEMS inertial sensors by sequentially updating output signals from the MEMS inertial sensors.

Abstract: Non-contacting means of measuring the material velocities of harmonic acoustic telemetry waves travelling along the wall of drillpipe, production tubing or coiled tubing are disclosed. Also disclosed are contacting means, enabling measurement of accelerations or material velocities associated with acoustic telemetry waves travelling along the wall of the tubing, utilizing as a detector either a wireless accelerometer system or an optical means, or both; these may also be applied to mud pulse telemetry, wherein the telemetry waves are carried via the drilling fluid, causing strain in the pipe wall that in turn causes wall deformation that can be directly or indirectly assessed by optical means. The present invention enables detection of telemetry wave detection in space-constrained situations. The invention also teaches a substantially contactless method of determining the time-based changes of the propagating telemetry waves.

Abstract: A bulk micromachined vibratory gyro in which a proof mass has a bulk substrate thickness for a large mass and high inertial sensitivity. In embodiments, optical displacement transduction is with multi-layer sub-wavelength gratings for high sensitivity and low cross-talk with non-optical drive elements. In embodiments, the vibratory gyro includes a plurality of multi-layer sub-wavelength gratings and a plurality of drive electrodes to measure motion of the proof mass induced by drive forces and/or moments and induced by the Coriolis Effect when the gyro experiences a rotation. In embodiments, phase is varied across the plurality gratings and a multi-layer grating having the best performance is selected from the plurality.

Abstract: A device for measuring angle and angular velocity or distance and speed of a moving part is described. The device has a sensor which is or can be arranged in a stationary manner and an encoder which is or can be arranged on the moving part and, together with the sensor, generates a modulation signal to be demodulated by the sensor. For the frequency measurement which is needed to measure the angular velocity/speed, the encoder has a structure which reproduces a periodic pattern and is interrupted by at least one index area for the angle/distance measurement. In the index area, the encoder has a substitute pattern which differs from the periodic pattern by at least one physical variable which can be detected by the sensor but has a structure which also enables the frequency measurement in the index area.

Abstract: Embodiments relate to integrated sensors and sensing methods. Embodiments relate to integrated sensor layouts. Embodiments are configured to maximize a ratio of sensor spacing over a die area. While being generally applicable to many different types of sensors, particular advantages can be presented for magnetoresistive (xMR) sensors.

Abstract: A microelectromechanical system device including anchors and mass is provided. Electrical interconnections are formed on the mass by using a insulation layer of mass, an electrical insulation trench and conductive through hole. The electrical interconnections replace the cross-line structure without adding additional processing steps, thereby reducing the use of the conductive layer and the electrical insulation layer. A method for fabricating the microelectromechanical system device is also provided.

Abstract: A laser gyro includes a cylindrical solid amplifier bar having an axis of revolution. The laser gyro also includes: an annular piezoelectric element for exciting said solid amplifier element at a predetermined frequency f, along said axis of revolution, said annular piezoelectric element being mounted fixed on one of the two end cross sections of the cylindrical solid amplifier bar so that its axis of revolution coincides with said axis of revolution of said cylindrical solid amplifier bar; and an annular dynamic counterweight mounted fixed on the free end cross section of said annular piezoelectric element so that its axis of revolution coincides with said axis of revolution of said cylindrical solid amplifier bar; said cylindrical solid amplifier bar being dimensioned so as to be considered nondeformable at said excitation frequency f.

Abstract: An angular rate sensor includes a metallic core board having a core meal layer made of a metal plate and a wiring layer including a wiring structure, a semiconductor device for detecting an angular rate fixed on the core metal layer, and a cap fixed to the wiring layer. The semiconductor device for detecting an angular rate is disposed in a hollow chamber formed by the cap and the metallic core board. The metallic core board, the semiconductor device, and the cap are molded with resin. Consequently, the angular rate sensor has a packaging structure in which electromagnetic noise resistance and moisture resistance are improved while stress applied to the semiconductor device for detecting an angular rate is reduced.

Abstract: An inertial sensor is described that has a commanded test function. The sensor is of a ring type driven by a driver circuit, the sensor further comprising primary and secondary portions having corresponding signal pickoffs. The primary pickoff signal amplitude is controlled via an automatic gain control, the primary phase lock loop and VCO locks to the resonant frequency to provide the clocks for the synchronous detectors, the primary pickoff signals via the primary phase shift circuit is provided to the primary driver, the secondary pickoff signal being input into a detector circuit capable of detecting motion in the sensor. The commanded test function comprises signal derived from the primary portion of the circuit and input into the two inputs of a differential amplifier in the secondary pickoff detector circuit.

Abstract: In an angle detection method with a resolver, the method being for detecting a rotational angle of a rotator by synchronously detecting a first signal and a second signal that are two phase sine wave modulation signals obtained from a one phase excitation/two phase output resolver, the method includes: a first signal detection process which detects a signal in the order of the first signal and the second signal; and a second signal detection process which detects a signal in the order of the second signal and the first signal.

Abstract: An angular rate sensor comprises a piezoelectric film having a first and a second surfaces forming an x-y plane and utilizes a perturbation mass coherently vibrating elastic acoustic waves on which a Coriolis force acts when the angular rate sensor undergoes a rotary motion about an x-direction. A first elastic acoustic wave is excited in the piezoelectric film by a driving transducer and a second elastic acoustic wave generated by the Coriolis force proportional to an angular rate of the rotary motion of the angular rate sensor itself is detected by the detecting transducer. The angular rate sensor further comprises at least a first electrode disposed on the first surface of the piezoelectric film for discharging a surface charge caused due to piezoelectric effect at the lower surface of the film in which the first elastic acoustic wave is excited.

Abstract: The present invention teaches a novel apparatus and method for providing the magnetic impulse required to drive an electronic pickup used to indicate the speed of a bicycle. In a conventional spoked wheel, one of the spokes is fabricated from a magnetic material such that each time that particular spoke passes the pickup the requisite current impulse is transmitted to the handlebar mounted receiving unit.

Abstract: Microelectromechanical system (MEMS) devices and methods with controlled die bonding areas. An example device includes a MEMS die having a glass layer and a protective package. The glass layer includes a side facing the protective package with at least one mesa protruding from a recessed portion of the glass layer. The at least one mesa is attached to the protective package. An example method includes creating at least one mesa on a glass layer of a MEMS die and attaching the at least one mesa to a protective package.

Abstract: A rotation detecting apparatus includes core member having a receiving hole, an inner member that is rotatably supported b the core member, and an outer member that constitutes a wheel bearing device. The rotation detecting apparatus also includes a rotation detecting sensor, an external lead cable that is drawn out from an inner space through the receiving hole in the core member and a sealing member that is secured to an outer peripheral surface of the external lead cable.

Abstract: A yaw rate sensor has two sets of exciting electrodes, perturbative weights and two sets of detecting electrodes on a surface of a piezoelectric substrate. The exciting electrodes excite first surface acoustic waves transmitted through the surface of the substrate in a propagation direction. The weights are oscillated by the waves and excite a second surface acoustic wave, transmitted through the surface of the substrate in a detection direction orthogonal to the propagation direction, in response to a yaw applied to the weights. The detecting electrodes measure an intensity of the second surface acoustic wave to detect the yaw rate. The sets of exciting electrodes are symmetrically placed with respect to a driving axis extending straight along the propagation direction. The group of weights is symmetric with respect to the driving axis.

Abstract: Capacitive bulk acoustic wave x, y and z-axes gyroscopes implemented on (100) and (111) silicon substrates are disclosed. Exemplary gyroscopes comprise a handle substrate, a bulk acoustic wave resonator element supported by the handle substrate, and a plurality of electrodes surrounding and separated from the resonator element by very small capacitive gaps. The electrodes can excite and detect at least two degenerate bulk acoustic wave resonant modes in the resonator. Advantages include reduced size; higher Q, which improves noise and bias stability; larger bandwidth, and improved shock resistance. In addition, the high Q is maintained in atmospheric or near-atmospheric pressure which reduces the cost and complexity of the wafer-scale packaging of the gyroscope.

Abstract: An angular velocity detection apparatus includes a vibrator that generates a signal that includes an angular velocity component and a vibration leakage component, a driver section that generates the drive signal, and supplies the drive signal to the vibrator, an angular velocity signal generation section that extracts the angular velocity component from the signal generated by the vibrator, and generates an angular velocity signal corresponding to the magnitude of the angular velocity component, a vibration leakage signal generation section that extracts the vibration leakage component from the signal generated by the vibrator, and generates a vibration leakage signal corresponding to the magnitude of the vibration leakage component, and an adder-subtractor section that adds the vibration leakage signal to the angular velocity signal, or subtracts the vibration leakage signal from the angular velocity signal, in a given ratio to correct temperature characteristics of the angular velocity signal.

Abstract: A sensor that senses incident RF signals is provided. The sensor is capable of sensing signals in the Gigahertz (GHz) and Terahertz (THz) range. The sensor may utilize one or more cantilevers, an interferometer, or may be formed in a box-type configuration.

Abstract: An angular rate sensor comprises a piezoelectric film having a first and a second surfaces forming an x-y plane and utilizes a perturbation mass coherently vibrating elastic acoustic waves on which a Coriolis force acts when the angular rate sensor undergoes a rotary motion about an x-direction. A first elastic acoustic wave is excited in the piezoelectric film by a driving transducer and a second elastic acoustic wave generated by the Coriolis force proportional to an angular rate of the rotary motion of the angular rate sensor itself is detected by the detecting transducer. The angular rate sensor further comprises at least a first electrode disposed on the first surface of the piezoelectric film for discharging a surface charge caused due to piezoelectric effect at the lower surface of the film in which the first elastic acoustic wave is excited.

Abstract: An angular velocity detection apparatus is disclosed. The angular velocity detection apparatus includes: a SAW angular velocity sensor; a synchronous detection unit configured to synchronously detect an output signal from the SAW angular velocity sensor by using a reference signal; and a switching signal generation unit. The switching signal generation unit cyclically switches on and off an input of a driving signal to the SAW angular velocity sensor, and switches on an input of the output signal to the synchronous detection unit when an unwanted wave is un-inputted to a sensing electrode of the SAW angular velocity sensor.

Abstract: A rotation sensor has a substrate with a first surface and a second surface. A shear-wave transparent mirror is arranged on the first surface of the substrate, and a shear-wave isolator is arranged above the shear-wave transparent mirror, the shear-wave transparent mirror and the shear-wave isolator being arranged separated from each other to define a Coriolis zone there between. A bulk-acoustic-wave resonator is arranged above the shear-wave isolator, and a shear-wave detector is arranged on the substrate in a direction, in which a shear-wave generated by the bulk-acoustic-wave resonator upon rotation propagates.

Abstract: The apparatus in one embodiment may have capacitive bulk acoustic wave disk gyro operated in a closed loop mode. A self-calibration system may be operatively coupled to the capacitive bulk acoustic wave disk gyroscope. Self-calibration of gyro bias of the gyro may be implemented by interchanging an anti-nodal axis with a nodal axis of the gyro.

Abstract: The present invention relates to encapsulated electrical/electronic devices and the use of polyamide compositions comprising at least one semi-aromatic polyamide and at least one aliphatic semi-aromatic polyamide, in particular, for encapsulating electrical/electronic devices.

Abstract: Improved methods and systems for feedback signals in a sensor system. An example method demodulates a sense signal using an analog demodulator and also demodulates the sense signal using a digital demodulator. The difference between the result of the analog demodulator and the digital demodulator is determined and then integrated. A sensor feedback control signal is generated based on the integrated difference.

Abstract: A fiber optic coil assembly and a method of winding the same include a fiber optic coil configured to eliminate a jog zone, which is found in conventionally fiber optic coil assemblies and tends to weaken the coil. The fiber optic coil assembly includes at least two layers of coil. A first layer is cylindrically wound in a first rotational direction and in a first linear direction and includes coil diameters located substantially parallel to one another and extending over the first linear direction. A first lead portion extends from an end of the first layer through an opening defined by the wound first layer. A second layer is formed in a similar manner as the first layer, except it is wound in an opposite rotational direction. Additional layers may be included consistent with the winding process of the first or the second layer, respectively.

Abstract: A method of determining a speed of a wheel that involves providing a resolver having a rotor and a stator which resolver produces at least one output signal, operatively connecting the rotor to a wheel such that the resolver is rotated by the rotation of the wheel, producing digital signals indicative of a position of the rotor relative to the stator based on the at least one output signal, and calculating a velocity of the wheel from the digital signals. The digital signals may be used alone or in conjunction with analog wheel speed signals. Also a speed sensor for practicing this method.

Abstract: A rotation sensor has a substrate with a first surface and a second surface. A shear-wave transparent mirror is arranged on the first surface of the substrate, and a shear-wave isolator is arranged above the shear-wave transparent mirror, the shear-wave transparent mirror and the shear-wave isolator being arranged separated from each other to define a Coriolis zone there between. A bulk-acoustic-wave resonator is arranged above the shear-wave isolator, and a shear-wave detector is arranged on the substrate in a direction, in which a shear-wave generated by the bulk-acoustic-wave resonator upon rotation propagates.

Abstract: Dithering mechanism and method for eliminating the effects of zero-rate bias in a rate sensor or gyroscope. Both continuously moving and indexing embodiments are disclosed. The mechanism includes a first part mounted in a fixed position centered about a dither axis perpendicular to the input axis of the gyroscope, a second part disposed coaxially of the first part and affixed to the sensing element of the gyroscope, and a plurality of piezoelectrically driven quartz flexure beams extending radially between the first and second parts for dithering the second part about the dither axis. In some embodiments, the dithering mechanism is formed separately from and affixed to the sensing element of the gyroscope, and in others it is formed integrally with the sensing element.

Abstract: Capacitive bulk acoustic wave x, y and z-axes gyroscopes implemented on (100) and (111) silicon substrates are disclosed. Exemplary gyroscopes comprise a handle substrate, a bulk acoustic wave resonator element supported by the handle substrate, and a plurality of electrodes surrounding and separated from the resonator element by very small capacitive gaps. The electrodes can excite and detect at least two degenerate bulk acoustic wave resonant modes in the resonator. Advantages include reduced size; higher Q, which improves noise and bias stability; larger bandwidth, and improved shock resistance. In addition, the high Q is maintained in atmospheric or near-atmospheric pressure which reduces the cost and complexity of the wafer-scale packaging of the gyroscope.

Abstract: A yaw rate sensor has two sets of exciting electrodes, perturbative weights and two sets of detecting electrodes on a surface of a piezoelectric substrate. The exciting electrodes excite first surface acoustic waves transmitted through the surface of the substrate in a propagation direction. The weights are oscillated by the waves and excite a second surface acoustic wave, transmitted through the surface of the substrate in a detection direction orthogonal to the propagation direction, in response to a yaw applied to the weights. The detecting electrodes measure an intensity of the second surface acoustic wave to detect the yaw rate. The sets of exciting electrodes are symmetrically placed with respect to a driving axis extending straight along the propagation direction. The group of weights is symmetric with respect to the driving axis.

Abstract: Dithering mechanism and method for eliminating the effects of zero-rate bias in a rate sensor or gyroscope. Both continuously moving and indexing embodiments are disclosed. The mechanism includes a first part mounted in a fixed position centered about a dither axis perpendicular to the input axis of the gyroscope, a second part disposed coaxially of the first part and affixed to the sensing element of the gyroscope, and a plurality of piezoelectrically driven quartz flexure beams extending radially between the first and second parts for dithering the second part about the dither axis. In some embodiments, the dithering mechanism is formed separately from and affixed to the sensing element of the gyroscope, and in others it is formed integrally with the sensing element.

Abstract: A sensor array, in particular a micromechanical sensor array, and methods for manufacturing the sensor array are provided, which sensor array includes a sensor section for supplying certain sensor signals, and a cover section provided on the sensor section to form a hermetically sealed sensor interior. An electronic analyzer device is at least partially integratable into cover section for analysis of the sensor signals, and electrically connectable to a corresponding circuit device of the sensor section.

Abstract: A gyroscope comprises a piezoelectric substrate having a surface. Disposed on the surface are a resonator transducer, a pair of reflectors, a structure such as a metallic dot, and a sensor transducer. The resonator transducer creates a first surface acoustic wave on the surface. The pair of reflectors reflects the first surface acoustic wave to form a standing wave within a region of the surface between the pair of reflectors. The structure is disposed on the surface within the region, wherein a Coriolis force acting upon the structure creates a second surface acoustic wave. The sensor senses the second surface acoustic wave and provides an output indicative thereof.

Abstract: The hemispherical resonator comprises a bell fixed to a base which carries main electrodes extending in register with an edge of the bell, and a shield electrode subdivided into two portions each presenting auxiliary electrodes extending in regular manner between the main electrodes.

Abstract: A gyroscope comprises a piezoelectric substrate having a surface. Disposed on the surface are a resonator transducer, a pair of reflectors, a structure such as a metallic dot, and a sensor transducer. The resonator transducer creates a first surface acoustic wave on the surface. The pair of reflectors reflects the first surface acoustic wave to form a standing wave within a region of the surface between the pair of reflectors. The structure is disposed on the surface within the region, wherein a Coriolis force acting upon the structure creates a second surface acoustic wave. The sensor senses the second surface acoustic wave and provides an output indicative thereof.

Abstract: A gyroscope is based upon the integration of an optical resonant cavity and a photodiode to detect minute perturbations due to angular forces. A Fabry-Perot cavity is created from two parallel semitransparent mirrors used in conjunction with a monochromatic light source. One mirror is fixed while the other is allowed to rotate with respect to the first mirror. A resonant cavity is thereby formed on either side of the axis. The gap between the mirrors is set so that light transmission through the mirrors is optimized. Rotation of the mirror from this position causes the distance between the mirrors to be altered and the light transmission on either side of the rotational axis to be change. Photodiodes on these sides sense this change as a change in photo-generated current, enabling the amount of change in rotation to be calculated. The photo-currents can be differentially amplified for sensitivity.

Abstract: A gyroscope comprises a piezoelectric substrate having a surface. Disposed on the surface are a resonator transducer, a pair of reflectors, a structure such as a metallic dot, and a sensor transducer. The resonator transducer creates a first surface acoustic wave on the surface. The pair of reflectors reflects the first surface acoustic wave to form a standing wave within a region of the surface between the pair of reflectors. The structure is disposed on the surface within the region, wherein a Coriolis force acting upon the structure creates a second surface acoustic wave. The sensor senses the second surface acoustic wave and provides an output indicative thereof.