Thales

Régis Quer

Pierre-Olivier Lefort

Christophe Taurand

Bertrand Leverrier

Bernard Chaumet

Claude Rougeot

Olivier Lefort

Philippe Guichard

Jérôme Inglese

Louis Raillon

André Boura

Jean-Jacques Fyot

Jean-Michel Muguet

Fabien Filhol

Yann Planchette

Christine Debaillon-Vesque

Sébastien Simoens

Jean-René Chevalier

Serge Parbaud

Alain Fourrier

Sébastien Jaud

A microelectromechanical system comprising an assembly of layers stacked in a stacking direction comprises an active layer made of single-crystal silicon comprising an active structure, and first and second covers defining a cavity around the active structure, the active layer interposed between the first and second covers, the second cover comprising a single layer made of single-crystal silicon. The assembly comprises a decoupling layer made of single-crystal silicon and comprising: an attaching element fastened to a carrier, a frame encircling the attaching element in the plane of the decoupling layer, and a mechanical decoupling structure connecting the frame and the attaching structure, the mechanical decoupling structure allowing the attaching element to be flexibly joined to the frame. The frame is secured to the silicon layer of the second cover and at most one film of silicon dioxide is interposed between the frame and silicon layer of the second cover.

Microelectromechanical system and fabricating process having decoupling structure that includes attaching element for fastening to carrier

The invention relates to vibrating micro-systems, and notably but not exclusively to pressure, acceleration, or angular speed micro-sensors with a resonator in an evacuated cavity. The resonator () with a vibrating element is placed in an oscillating circuit controlled by a closed-loop control, the oscillating circuit supplying an oscillating signal y(t) at a resonance frequency Fp representing the measurement of a physical quantity. The resonance frequency is calculated by counting pulses over a time window. The sensor furthermore comprises means for calculating a continuity parameter Pc representing the variations in the result of the calculation of the resonance frequency over the course of the successive time windows, and means for comparing the parameter Pc with a threshold in order to deduce from this information on the degradation of the precision of the sensor.

Sensor with a vibrating member in a cavity with integrated anomaly detection

A micro-system, for example a micro-sensor, includes a resonatorwith vibrating element(s)receiving an excitation signal E of a loopfor automatic gain control, as a function of an amplitude setpoint (C) and providing as output a signal y(t) defined by a peak amplitude having a nominal value Adependent on the said setpoint and a resonant frequency. The micro-sensor integrates a circuit for measuring a quality factor of the resonator based on a measurement of an attenuation of the output signal during a momentary phase of cutoff of the excitation signal E applied to the resonator. This circuit for measuring the quality factor is configured so as to activate the excitation signal cutoff phase, for a duration of cutoff Tsuch that at the end of the cutoff phase, the peak amplitude of the output signal is attenuated by factor to the nominal peak amplitude Aat the start of the cutoff phase, by a factor k with 1&#x3c;k&#x2266;2.

Vibrating micro-system with automatic gain control loop, with integrated control of the quality factor

A micromachined accelerometer in a flat plate includes a base and at least two resonator measuring cells provided with a common mobile seismic element, the two measuring cells being placed one on each side of the common mobile seismic element along the sensitive axis of the accelerometer, such that under the effect of an acceleration, the resonator of one measuring cell undergoes a traction while the resonator of the other measuring cell undergoes a compression, the measuring cells respectively configured to amplify the acceleration force generating the translation of the common mobile seismic element provided with a respective anchoring foot-piece. The common mobile seismic element includes at least two mobile seismic masses able to be displaced in translation along the sensitive axis of the accelerometer and/or in rotation with respect to a respective axis of rotation substantially orthogonal to the sensitive axis under the effect of an acceleration along the sensitive axis.

Micro-machined accelerometer

An electrostatic device for damping a mechanical vibration movement of a moving object, the moving object being made of an electrically conductive material, the movement of the moving object having at least one parasitic vibration mode of frequency fto be damped, the device comprising an electrode ELE forming, with the moving object, a gap of capacitance C voltage-biased with a DC voltage Vby a biasing circuit, the biasing circuit comprising, electrically connected in series with the electrode ELE: a load resistance R; possibly an inductance L; a parasitic capacitance C, characterized in that the biasing circuit further includes an electronic compensating device DEC having an impedance Z, which comprises a capacitance component C, a resistance component Req, and possibly an inductance component L.

Electrostatic device for damping a mechanical vibration movement of a resonant moving object

Accelerometer micromachined in a plane plate comprising a base, and at least one measurement cell including a moveable seismic mass connected to the base and capable of moving translationally along the sensitive y axis of the accelerometer under the effect of an acceleration &#x3b3; along this y axis, a resonator cell that comprises a resonator that can vibrate and be subjected to a tensile or compressive force depending on the direction of the acceleration &#x3b3; and is placed symmetrically with respect to an axis of symmetry S of the structure, this axis S being parallel to the y axis and passing through the center of gravity of the seismic mass, the measurement cell furthermore including amplification means for amplifying the acceleration force, which means comprise at least one anchoring foot for anchoring to the base, two rigid terminations of the resonator cell and two pairs of micromachined arms symmetrical with respect to the axis S, each pair comprising a first arm connecting a termination to the seismic mass, and a second arm connecting the same termination to the anchoring foot, the angle &#x3b1; between the Ox axis and the first arm being small enough for the tensile or compressive force exerted on the resonator to be greater than the acceleration force exerted on the seismic mass.

Vibrating beam accelerometer

The invention relates to low-frequency underwater detection systems comprising a towed linear antenna (). It consists in producing the transducers of the transmission antenna () in the form of flextensional arrays of cylindrical type () and in forming directional transmission channels covering all of space. It makes it possible to lighten the assembly and to facilitate implementation at sea, which becomes able to be automated.

Towed low-frequency underwater detection system

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Saint Peray, France

Régis Quer