Eta Sa Manufacture Horlogere Suisse

Eta Sa Fabriques D'ebauches

Bruno Studer

Silvio Dalla Piazza

Thomas Luethi

Felix Staub

Walter Zingg

Thomas Lüthi

Thomas L&uuml;thi

The tuning fork resonator () includes a base () from which first and second parallel vibrating arms () extend, carrying a set of excitation electrodes () for vibrating the arms at a fundamental frequency. Grooves () are formed on at least one of the top or bottom surfaces of each of said arms. The vibrating arms have a generally tapered shape, and are extended by an enlarged flipper shaped portion () which forms the free end of each arm. The groove () is extended in the direction of the free end of an arm to beyond the start of the flipper () so as to increase said first motional capacitance of the resonator for the fundamental frequency, to decrease said second motional capacitance of the resonator for the partial frequency and to ensure better distribution of mechanical stress along the vibrating arms and to increase shock resistance.

Piezoelectric resonator with optimised motional capacitances

A transducer for measuring an angular velocity formed by a single piezoelectric tuning fork () that rotates at the angular velocity. The tuning fork has a detection leg () which has a cross-shaped section including two top lateral faces () and two bottom lateral faces () separated by protruding parts () projecting with respect to the faces. The detection leg has detecting electrodes which are arranged such that the electrical field between electrodes is substantially rectilinear through the detection leg.

Angular speed measuring transducer

The invention concerns a piezoelectric resonator (), intended to be packaged in a case, including a base () formed of a first fixing zone (), a second central mechanical uncoupling zone () and a third zone () opposite to the first fixing zone. At least two vibrating arms () extend from said third zone, on each of which at least one groove (--) is formed on at least one of the top or bottom faces of the arms. The resonator is characterised in that the base is provided with a hole () through the second central mechanical uncoupling zone.

Quartz resonator of small dimensions

A transducer for measuring an angular velocity formed by a single piezoelectric tuning fork () that rotates at said angular velocity, including first () and second () vibrating legs extending from a base (), excitation electrodes () arranged on the excitation leg (), detection electrodes (), arranged on the detection leg (), characterized in that the detection leg includes at least one first groove () on the top face and at least one second groove () on the bottom face, and in that the detection electrodes include first and second detection electrodes arranged facing each other, the first () respectively the second detection electrode () being arranged on one lateral flank of the groove () respectively of the groove () such that the electrical field between the first and second detection electrodes is substantially rectilinear through the detection leg, and third and fourth detection electrodes arranged facing each other, the third () respectively the fourth detection electrode () being arranged on one lateral flank of the groove () respectively of the groove (), such that the electrical field between the third and fourth detection electrodes is substantially rectilinear through the detection leg.

The piezoelectric resonator according to the invention includes a tuning fork shaped part with two parallel vibrating arms, connected to each other by a linking part, from which protrude a central arm located between both vibrating arms of the tuning fork shaped part, the vibrating arms carrying first electrodes to make them vibrate, these electrodes being connected to connection elements carried by the central arm, wherein a slot has been cut within the linking part opposite to the central arm and wherein second electrodes have been arranged along said slot.

Small-sized piezoelectric resonator

The invention concerns an assembly comprising a piezoelectric resonator and a case, said case including a main part with a bottom and sides, in which said resonator is mounted and a cover fixed to said main part, said resonator including a tuning fork shaped part with two parallel vibrating arms connected to each other by a linking part, and a central arm protruding from said linking part and located between both vibrating arms carrying at least two electrodes to make them vibrate, these two electrodes being connected respectively to at least first and second connection pads located on a back face of said central arm oriented toward the bottom of the case, said case further comprising at least one support secured to its bottom on which said central arm of the resonator is fixed by means of at least first and second connection elements located on said support and electrically connected respectively to said first and second connection pads by a conductive adhesive, wherein guiding means are provided at least with either said first connection pad or element being located on the linking part side in order to flow excess of said conductive adhesive away from the second electrode being not electrically connected to said first connection pad or element with said guiding means.

Piezoelectric resonator and assembly comprising the same enclosed in a case

The piezoelectric resonator according to the invention includes a tuning fork shaped part with two parallel vibrating arms, connected to each other by a linking part, from which protrude a central arm located between both vibrating arms of the tuning fork shaped part, wherein at least one groove is formed on at least one of a front side and a rear side of each vibrating arm.

A resonator has a parallelepipedal bar of a piezoelectric material designed to vibrate in an extension mode, and suspension means of said bar which form a single, integral part with the latter and which are only connected to one of its lateral faces. This arrangement makes it possible to reduce the number of parasitic vibration modes which could couple to the main mode as well as coupling between these modes, and hence variations as a function of the temperature in the characteristics of the resonator, notably in its quality factor.

Resonator having a bar designed to vibrate in one extension mode

The resonator obtained by this process comprises an active central portion, the thickness of which is reduced until the desired frequency is obtained. This may be of the order of 50 to 100 MHz. This central portion is surrounded by a considerably thicker reinforcing frame to which it is mechanically connected by means of one or more connecting members which are thinner than the active portion. The connecting member or members eliminate the need for coupling between the reinforcing frame and the active portion. Electrodes are provided for exciting the resonator.

Growing community of inventors

Riedholz, Switzerland

Bruno Studer