公开(公告)号：US20190079453A1

公开(公告)日：2019-03-14

申请号：US16104212

申请日：2018-08-17

Applicant: The Swatch Group Research and Development Ltd

Inventor： Alexandre HAEMMERLI ,  Francois GUEISSAZ ,  Lionel TOMBEZ ,  Bernhard SCHNYDER ,  Silvio DALLA PIAZZA

IPC: G04B17/06

Abstract: The present invention concerns a piezoelectric element (3) for an automatic frequency control circuit. The element includes a balance spring (7) formed of a strip of piezoelectric material, a first electrode connected to the automatic control circuit, and disposed on all or part of one side of the strip, and a second electrode connected to the automatic control circuit and disposed on all or part of another side of the strip of piezoelectric material. The element further comprises at least two discontinuous layers of an insulating material, each discontinuous layer of insulating material being disposed on at least one side of the strip of piezoelectric material and separating a first electrode from a second electrode. The discontinuous layers of insulating material are distributed on predetermined portions of the balance spring substantially forming arcs, with a predetermined angular periodicity.