Abstract: 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.

Abstract: 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.

Abstract: The micro-electro-mechanical system is provided with at least two separate anchoring elements (F1, F2) designed to be bound to a support. A anchoring element (F1, F2) is solidly linked to at least one beam (P1, P2) that can be deformed in bending, and two beams (P1, P2) respectively linked to two distinct anchoring elements (F1, F2) have different directions. A beam has a length L, a thickness e, and a height h, such that the stiffnesses KL in the directions of the length and of the height Kh are large and the stiffness in the direction of the thickness Ke is small.

Abstract: A micro-system, for example a micro-sensor, includes a resonator 10 with vibrating element(s) 11 receiving an excitation signal E of a loop 20 for 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 A0 dependent 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 Td such that at the end of the cutoff phase, the peak amplitude of the output signal is attenuated by factor to the nominal peak amplitude A0 at the start of the cutoff phase, by a factor k with 1<k?2.

Abstract: A micro-system, for example a micro-sensor, comprises a resonator 10 with vibrating element(s) 11 receiving an excitation signal E of a loop 20 for 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 A0 dependent 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 Td such that at the end of the cutoff phase, the peak amplitude of the output signal is attenuated by factor to the nominal peak amplitude A0 at the start of the cutoff phase, by a factor k with 1<k?2.

Abstract: The micro-electro-mechanical system is provided with at least two separate anchoring elements (F1, F2) designed to be bound to a support. A anchoring element (F1, F2) is solidly linked to at least one beam (P1, P2) that can be deformed in bending, and two beams (P1, P2) respectively linked to two distinct anchoring elements (F1, F2) have different directions. A beam has a length L, a thickness e, and a height h, such that the stiffnesses KL in the directions of the length and of the height Kh are large and the stiffness in the direction of the thickness Ke is small.

Abstract: 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.

Abstract: The invention relates to a device and a method for detecting a fault in a measurement device comprising a resonator and means for measuring a resonant frequency of the resonator. According to the invention, the device further includes means delivering information (S3) representative of the quality factor of the resonator (3) at the resonant frequency.

Abstract: The invention relates to a micromachined accelerometer in a flat plate comprising 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 whilst the resonator of the other measuring cell undergoes a compression, said measuring cells respectively comprising means of amplification of the acceleration force generating the translation of the common mobile seismic element provided with a respective anchoring foot-piece.

Abstract: The invention relates to a method of correcting the effects of aging of a measurement sensor upon turning on the sensor. It also relates to a device delivering measurements corrected for the effects of aging of the device. According to the invention, the method of correcting the effects of aging of a sensor starts by on turning on the processing unit. The absolute time information is transmitted from a satellite positioning receiver to a processing unit. The age of the sensor is determined by comparison of the date of manufacture of the sensor and the absolute time information. Corrections to be made to a sensor measurement, based on the age of the sensor and on the degradation law, are determined. The corrections are applied to the sensor measurement.

Abstract: The invention relates to a method of correcting the effects of aging of a measurement sensor upon turning on the sensor. It also relates to a device delivering measurements corrected for the effects of aging of the device. According to the invention, the method of correcting the effects of aging of a sensor starts by on turning on the processing unit. The absolute time information is transmitted from a satellite positioning receiver to a processing unit. The age of the sensor is determined by comparison of the date of manufacture of the sensor and the absolute time information. Corrections to be made to a sensor measurement, based on the age of the sensor and on the degradation law, are determined. The corrections are applied to the sensor measurement.

Abstract: The invention relates to a device and a method for detecting a fault in a measurement device comprising a resonator and means for measuring a resonant frequency of the resonator. According to the invention, the device further includes means delivering information (S3) representative of the quality factor of the resonator (3) at the resonant frequency.

Abstract: The invention relates to gyroscopes having a vibrating structure that is micromachined in a silicon substrate. A novel vibrating structure is described, which has two moving masses 14 and 14?, connected by a vibration energy coupling structure (transverse arms 26, 26?, longitudinal arms 22, 22?, and a short transverse link 24 between the longitudinal links 22, 22?). The moving masses are also suspended from U-shaped flexure arms (13), having one branch end connected to the mass and another end connected to a fixed anchoring point 18. The flexure arms are not inserted between the coupling structure and the mass, but are independent of the coupling structure. The masses are excited so as to vibrate in their plane by electrostatic forces applied by interdigitated combs 11. The Coriolis forces make them vibrate perpendicular to the plane, and this vibration is detected by electrodes forming part of the moving masses.

Abstract: Unlike customary vibrating mass gyros which operate by exciting a first fundamental mode of vibration of the vibrating mass and by detecting the effect of the Coriolis force on a second fundamental mode of vibration of the vibrating mass orthogonal to the first mode, this gyro operates by giving its suspended mass a circular motion alternately in the forward and reverse directions and by deducing the gyrometric effect from the difference between the apparent frequencies of the circular motion of the suspended mass in one direction and in the other. This allows a considerable reduction in the drafting of the heading measurement obtained with this type of gyro.

Abstract: The invention relates to a process for fabricating a microstructure containing a vacuum cavity. The invention includes producing, from a first silicon wafer, a porous silicon region intended to form, completely or partly, one wall of the cavity and capable of absorbing residual gases in the cavity and joins the first silicon wafer to a second wafer, so as to produce the cavity.

Abstract: Unlike customary vibrating mass gyros which operate by exciting a first fundamental mode of vibration of the vibrating mass and by detecting the effect of the Coriolis force on a second fundamental mode of vibration of the vibrating mass orthogonal to the first mode, this gyro operates by giving its suspended mass a circular motion alternately in the forward and reverse directions and by deducing the gyrometric effect from the difference between the apparent frequencies of the circular motion of the suspended mass in one direction and in the other. This allows a considerable reduction in the drafting of the heading measurement obtained with this type of gyro.

Abstract: The invention relates to gyroscopes having a vibrating structure that is micromachined in a silicon substrate. A novel vibrating structure is described, which has two moving masses 14 and 14′, connected by a vibration energy coupling structure (transverse arms 26, 26′, longitudinal arms 22, 22′, and a short transverse link 24 between the longitudinal links 22, 22′). The moving masses are also suspended from U-shaped flexure arms (13), having one branch end connected to the mass and another end connected to a fixed anchoring point 18. The flexure arms are not inserted between the coupling structure and the mass, but are independent of the coupling structure. The masses are excited so as to vibrate in their plane by electrostatic forces applied by interdigitated combs 11. The Coriolis forces make them vibrate perpendicular to the plane, and this vibration is detected by electrodes forming part of the moving masses.

Abstract: A mechanical structure (100) comprises a moving mass (3) suspended by beams (4, 5, 6, 7) from a fixed frame (2). The structure (100) comprises elongation means (23-26) mechanically connected to each of the beams (4, 5, 6, 7). The elongation means is designed such that the stiffness of the beams (4, 5, 6, 7) varies only little during movement of the moving mass. The structure is characterized in that the response of an elongation means is asymmetric when acting in tension and in compression. The structure is thus made insensitive to accelerations along a direction parallel to the suspension direction.

Abstract: A mechanical structure (100) comprises a moving mass (3) suspended by beams (4, 5, 6, 7) from a fixed frame (2). The structure (100) comprises elongation means (23-26) mechanically connected to each of the beams (4, 5, 6, 7). The elongation means is designed such that the stiffness of the beams (4, 5, 6, 7) varies only little during movement of the moving mass. The structure is characterized in that the response of an elongation means is asymmetric when acting in tension and in compression. The structure is thus made insensitive to accelerations along a direction parallel to the suspension direction.

Abstract: A micro-accelerometer having three micromachined conducting-silicon plates bonded in superposition with the interposition of insulating layers. The central plate includes a subassembly sensitive to acceleration, and a peripheral frame electrically insulated from the subassembly and surrounding the subassembly. The peripheral frame forms a spacer between a lower plate and an upper plate from which it is also electrically insulated. The subassembly includes a base fixed on the lower plate and a cantilevered proof mass suspended from the base, an electrical connection being made between the lower plate and the base of the subassembly.