Eta Sa Manufacture Horlogere Suisse

Micro Crystal Ag

Micro Crystal Sa

Felix Staub

Silvio Dalla Piazza

Bruno Studer

The invention relates to a piezoelectric resonator, which comprises a base and at least two vibrating arms () extending from the base, at least two grooves () being formed opposite each other on part of the length of the arms and on upper and lower faces of the arms. The depth of the groove on the upper face is less than 30% of the total thickness of each arm and the depth of the groove on the lower face is more than 50% of the total thickness of each arm, or reversely.

Small piezoelectric resonator

The piezoelectric resonator () includes a first and a second planar tuning fork shaped part arranged in a common plane. It is intended to be mounted on a support via a linking part (), the linking part being arranged to connect the tips of the inner vibrating arms () of the first and second tuning fork shaped parts so as to link the first and second tuning fork shaped parts together, The electrodes carried by the first and second tuning fork shaped parts are interconnected through the linking part so as to make the outer vibrating arms of the first and second tuning fork shaped part oscillate with opposite phase.

Small-sized piezoelectric tuning-fork resonator

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.

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Koppigen, Switzerland

Felix Staub