Piezoelectric element for an automatic frequency control circuit, oscillating mechanical system and device comprising the same
AssigneeThe Swatch Group Research and Development Ltd
InventorsAlexandre Haemmerli, Francois Gueissaz, Lionel Tombez, Bernhard Schnyder, Silvio Dalla Piazza
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Abstract
A piezoelectric element for an automatic frequency control circuit. The element includes a balance spring formed of a piezoelectric crystal strip, a first electrode connected to the automatic control circuit, and disposed on at least a first side of the strip, and a second electrode connected to the automatic control circuit and disposed on at least a second side of the strip. The first and second electrodes are placed on one portion or over the entire length of the balance spring in a predetermined angular distribution.
Claims19
A piezoelectric element for an automatic frequency control circuit, the piezoelectric element comprising:
- a balance spring formed of a strip of piezoelectric material;
- a first electrode, intended to be connected to the automatic frequency control circuit, and disposed on at least a first side of the strip of piezoelectric material;
- a second electrode, intended to be connected to the automatic frequency control circuit, and disposed on at least a second side of the strip of piezoelectric material;
- wherein the piezoelectric material is a piezoelectric crystal or a piezoelectric ceramic;
- wherein the first and second electrodes are placed on one portion or over the entire length of the balance spring in a predetermined angular distribution,
- wherein the first and second electrodes are disposed on one portion of an outer coil of the balance spring, said portion including one end of the balance spring and defining a predetermined angular sector, and
- wherein the first electrode includes first portions disposed on the first side of the strip of piezoelectric material and second portions disposed on at least one side of the strip of piezoelectric material distinct from the first side;
- wherein the second electrode includes first portions disposed on the second side of the strip of piezoelectric material and second portions disposed on at least one side of the strip of piezoelectric material distinct from the second side;
- the first and second portions of the first electrode respectively the second electrode being alternately connected to each other in junction areas;
- and wherein said junction areas are distributed over the balance spring with a predetermined angular periodicity.
Dependencies are inferred from the claim text.