Ecole Nationale Superieure De Mecanique Et Des Microtechniques

Schlumberger Technology Corporation

Etat Francais

Etat Francais Represente Par Le Delegue General Pour L'armement

Etat Francais Represented by the Delegue General Pour L ' Armement

L'etat Francais Represente Par Le Delegue Ministeriel

Laboratoires De Physicochimie Appliquees Issec

Kdp Societe Anonyme Keller Dorian Papiers

Raymond J Besson

Jean-Pascal Valentin

Pierre Maitre

Richard Delaite

Jean-Jacques Boy

Georges Renard

Jean P Valentin

Michel Valdois

Gerard Genestier

Marc Mourey

Jean-Louis Vaterkowski

Serge Galliou

Roger F Bourquin

Pierre C Maitre

Michael D Decailliot

Bernard M Dulmet

Daniel Thiebaud

The present invention relates to a piezoelectric resonator having adherent or non-adherent electrodes, the piezoelectric crystal comprising a central portion and a peripheral portion forming a ring that surrounds the central portion and that is connected thereto by an intermediate portion in which a slot is formed, the peripheral portion being connected to the central portion by a single connection bridge constituted by a non-slotted portion of said intermediate portion that extends over a small fraction of the periphery of said intermediate portion. The central portion constitutes the active vibrating portion of the crystal and the peripheral portion is held in the box by fastening means disposed in such a manner as to be thermally as remote as possible from the single connection bridge. The secured portion and the bridge constitute means for suspending the crystal.

Resonator for a thermostatically-controlled oscillator having low power

A monoaxial differential accelerometer with frequency output, includes a thin monolithic piezoelectric sensitive plate (10) in which plane a sensitive axis (X) is located. The plate (10) comprises two rectilinear slits (15, 15') parallel with the sensitive axis (X) and defining between them two zones of vibration aligned along the sensitive axis (X) and identically sensitive to the temperature variations. Each vibration zone is located between two electrodes (3, 4, 3, 4') to form resonators (20, 21) whose frequency variations are added for an acceleration directed along the sensitive axis (X) and whose the frequency variations are subtracted for an acceleration directed in a plane perpendicular to the sensitive axis (X). The resonators (20, 21) are inserted in the circuits of two oscillators (73, 74) whose beat frequency constitutes the output signal of the differential accelerometer.

Piezo electric resonator differential accelerometer

A supporting device including four independent and identical U-shaped coupling flanges each cooperating with a pair of springs. Each spring is formed of a circular cross section metal wire made of high elastic limit alloy. The set of coupling flanges and springs is symmetrical with respect to two mutually perpendicular axial planes of resonator and with respect to a central plane of the resonator. A cylindrical element is mounted inside the casing in a region of a lateral wall of the housing and has a circular groove on its inner face and located on a center plane parallel to the top and bottom walls of the housing. For each pair of springs cooperating with a coupling flange, one of the springs engages by a first portion into an upper slot formed in a planar rear face of the coupling flange and by a second portion in the circular groove. The inner faces of the coupling flanges rest directly on the edge of the top and bottom faces of the resonator.

Dismountable device for supporting a piezoelectric resonator inside a

Device for supporting a piezoelectric resonator inside a casing. The device comprises two cross-shaped half-shells, each one comprising: four branches of which the free ends define angle pieces with a horizontal bearing surface of small dimension, which surface is slightly raised with respect to the central part of the corresponding half-shell, as well as one vertical branch holding the edge of the resonator: four identical independent securing flanges to secure the two half-shells in position, said flanges having the shape of a turned down U, each flange comprising, at the end of each branch of the U, two stop elements bearing against two superposed branches of the two half-shells, on the faces of those branches facing said horizontal bearing surfaces; and at least four pairs of springs for suspending the four securing flanges with respect to the casing. The symmetry of the device assembly with respect to three axes perpendicular one to the other, and the shape of the different elements considerably limit the influence of any external radial or axial effects on the resonator.

Device for supporting a piezoelectric resonator inside a casing

In a pressure transducer of the piezoelectric type, a resonator (10) is made up of a pellet (16) mounted inside an element designed to be subjected to the action of a pressure on its exterior face (18). The pellet (16) and the element (12) are cut in the same quartz block, using a cut which provides two vibration modes. The forces resulting from the external pressure are transmitted to the edge of the pellet (16) by connecting bridges (22, 23) whose orientation is chosen so that one of the vibration modes has maximum sensitivity to the forces while the other mode has a practically zero sensitivity.

Piezoelectric transducer, notably for pressure measurement

In a piezoelectric transducer (10) an external element (12) of tubular form receives a pressure, notably a pressure to be measured, on its external face (16). It is cut in a quartz crystal in one piece with a plate (25) capable of vibrating under the action of an electric stress and extending in a plane parallel to the longitudinal direction of the tubular element inside the latter. Each of the longitudinal edges of the plate is connected by a transverse connecting element (30, 31) to the internal face (14) of the tubular element so as to transmit forces (F1 and F2) resulting from the application of the external pressure to the plate (25) in a direction substantially parallel to its plane and perpendicular to the axis of the tubular element (12).

Piezoelectric pressure and/or temperature transducer

A heating system for an HF oscillator. The system comprises a reentrant cavity (10) controlling an UHF oscillator and sized to generate an UHF electric field with a frequency F much higher than the resonance frequency F.sub.Q of the piezoelectric crystal (50) of the HF oscillator which itself is located in the space between the central core (14) and the bottom (12) of the cavity and in such a manner that the two electrodes (34,35) of the oscillator are respectively located substantially in the planes of the free end of the central core (14) and of the inside of the bottom (12) of the cavity (10). The electrodes (34,35) are located in bores (16,15) in the conducting parts of the cavity in such a manner that the peripheral part of each electrode is surrounded at close proximity but without making contact with the wall of the corresponding bore (16,15). The electrodes (34,35) are connected to an HF oscillator by insulated leads (24,25).

Microwave warmup device for HF resonator

An autothermostatic high frequency oscillator comprising a piezoelectric resonator of the type having electrodes which are not adhered to the crystal. The contact between the part of the crystal 1 serving to support the vibrating part of the crystal and the dielectric plates 2,3 supporting the excited electrodes is limited to a discontinuous surface of reduced scope constituted by a finite number of elements of contact surface. At least an infra-red reflector screen (200) located at the very interior of the water tight cavity (400) surrounding the resonator is situated immediately adjacent said resonator and the electric power applied to the excited electrodes is at least in the range of about 50 microwatts. The invention permits one to achieve oscillators with small consumption of energy and high stability.

High frequency, thermostatically self controlled oscillator

A piezoelectric bi-resonator with electrodes not adhering to the crystal, comprising at least first and second plates in dielectric material on which plates are deposited respectively first and second electrodes, a third plate in dielectric material having faces opposed to the first and second plates respectively, on which faces are respectively deposited third and fourth electrodes, connected together, and a piezoelectric body constituted by two piezoelectric chips made of quartz, independent and similar, one of which is interposed between the said first and third electrodes, without contact therewith, and the other is interposed between the second and fourth electrodes without contact therewith, the said piezoelectric quartz chips being arranged so that their axes Y' are opposite.

Acceleration and temperature compensated piezoelectric bi-resonator

A piezoelectric resonator comprises a crystal having an outer peripheral portion connected to a central portion by an intermediate zone which is short in the radial direction, is hollowed out over its major part and has at least two connector bridges between the outer and central portions. Electrodes are arranged facing one of the main portions of the crystal which then forms the vibrating portion of the resonator. The non-vibrating main portion serves as a support for the crystal. The surfaces of the connector bridges are continuous with the corresponding surfaces of the vibrating portion.

Piezoelectric resonator

Piezoelectric resonator comprising a sealed box in which a vacuum has been formed or into which has been introduced a residual gas, within said box a piezoelectric crystal having first and second main opposite faces, a first metal electrode deposited on the first main face of the crystal and a second metal electrode deposited on the second main and opposite faces of the crystal, a first conductor connected to the first electrode and extending outside the box, a second conductor connected to the second electrode and extending outside the box and means for maintaining the crystal within the box, wherein the piezoelectric crystal comprises a central portion and a peripheral portion forming a ring which spacedly surrounds the central portion and connected to said central portion by an intermediate portion which over at least part of the distance between the central portion and the peripheral portion has a reduced thickness compared with the thickness of said central and peripheral portions wherein the first and second electrodes are deposited on one of said central and peripheral portions which then constitutes the active part of the crystal, while the other portion which does not carry electrodes is immobilized in the box by retaining means which act in localized zones, the intermediate portion of the crystal and said immobilized portion constituting the suspension means for the active part of the crystal.

Piezoelectric resonator with improved suspension

Quartz resonator with electrodes that do not adhere to the crystal. Quartz resonator having improved medium-term and long-term stabilities and permitting easier placing on frequency. The resonator comprises, inside a tight housing 1, a condenser formed by two disks 3, 4 made of a dielectric material and separated by a removable ring 2 which determines the spacing between the disks 3 and 4. Electrodes are formed by metallization on the faces of the disks 3 and 4 located opposite a quartz crystal 1 enclosed in said condenser. The spacings between the crystal 1 and the disks 3 and 4 are considerably less than 1 millimeter. Application, for example, in the fields of telecommunications and radars.

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Besancon, France

Raymond J Besson