Piezoelectric element for an automatic frequency control circuit, oscillating mechanical system and device comprising the same, and method for manufacturing the piezoelectric element

• Main Authors: Haemmerli, Alexandre, Gueissaz, Francois, Dalla Piazza, Silvio, Schnyder, Bernhard, Tombez, Lionel
• Format: Patent
• Language: English
• Published: 20.04.2021
• Subjects: ELECTRICITY; ELECTROMECHANICAL CLOCKS OR WATCHES; HOROLOGY; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; MECHANICALLY-DRIVEN CLOCKS OR WATCHES; PHYSICS; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS

A piezoelectric element for an automatic frequency control circuit, the element including: a balance spring formed of a strip of piezoelectric material; at least a first electrode, configured to be connected to the circuit and being disposed on all or part of one side of the strip; at least a second electrode configured to be connected to the circuit and being disposed on all or part of another one side of the strip distinct from the one side on which the first electrode is disposed, the piezoelectric material being a piezoelectric crystal or a piezoelectric ceramic; and at least two discontinuous layers of an insulating material, each discontinuous layer being disposed on at least one side of the strip and separating the first electrode from the second electrode, the layers of insulating material being distributed on predetermined portions of the balance spring substantially forming arcs in a predetermined angular periodicity.