Patent ID: 8296953
Filing Date: 2012-10-30
Classification: G04B,G04D,Y10T

Abstract:
1. A method of manufacturing a one-piece hairspring with a raised terminal curve, the method including the following steps: a) providing a substrate including a top layer and a bottom layer of silicon-based materials, b) selectively etching at least one cavity in the top layer to form a first portion of an elevation element, made of silicon-based material, for the hairspring with the raised terminal curve, c) joining an additional layer of silicon-based material to the etched top layer of the substrate, d) selectively etching at least one cavity in the additional layer to form a second portion of the elevation element and to define patterns of a spiral-shaped balance spring having a thermo-elastic coefficient and a collet, made of silicon-based material, for the hairspring with the raised terminal curve, e) selectively etching at least one cavity in the bottom layer to form a third portion of the elevation element and to define a pattern of the raised terminal curve, made of silicon-based material, and f) releasing the one-piece hairspring with the raised terminal curve from the substrate so as to form the hairspring.