Frequency setting of a horological oscillator by optomechanical deformations

Patent metadata

Field	Value
Publication number	US-12572115-B2
Application number	US-202218056990-A
Country	US
Kind code	B2
Filing date	Nov 18, 2022
Priority date	Dec 27, 2021
Publication date	Mar 10, 2026
Grant date	Mar 10, 2026

Abstract

A method for the fine adjustment of the rate of a mechanical oscillator with an oscillating inertial mass, equipped, in a first step, with an actuator made of material suitable for irreversible local micro-expansion under the action of laser fires, to impart to an inertia-block a radial travel during suitable laser fires on a writing zone of the actuator, in a second step, the initial rate of the oscillator is set and measured, in a third step, the direction and the value of the deviation required to achieve a predetermined rate range, and of the travel to be imparted to inertia-blocks are calculated, in a fourth step, a writing zone is subjected to femtosecond laser fires to create expansion lines by local molecular expansion to radially deform the actuator, in a fifth step the rate is measured and the third step and fourth step are repeated if required.

First claim

The invention claimed is:

1 . A method for a fine adjustment of a rate of a mechanical horological oscillator comprising at least one inertial mass, arranged to oscillate about an axis of rotation and returned to a rest position by elastic return means, the method comprising:
in a first step, said oscillator is equipped with at least one inertial mass including an actuator in a material suitable for irreversible local micro-expansion under the effect of laser fires, said actuator being arranged to impart to an inertia-block a radial linear travel with respect to the axis of rotation, directly or with at least one travel amplifier, when a writing zone, included in the actuator is subjected to suitable laser fires; in a second step, a first rough setting of an initial rate of said oscillator is performed in a first rate range and said rate is measured; in a third step, a direction and the value of the rate deviation to be imparted to said oscillator are calculated to bring it the rate into a predetermined second rate range, and a direction and a value of the travel to be imparted to each said inertia-block included in said oscillator are calculated; in a fourth step, at least one said writing zone is subjected to femtosecond laser fires to create at least one expansion line by local molecular expansion of said material to deform said actuator radially with respect to said axis of rotation; and in a fifth step, the rate of said oscillator is measured, and if required said third step and said fourth step are repeated until the rate of said oscillator is within said second rate range.

2 . The method according to claim 1 , wherein said method is applied to said oscillator with at least two said inertial masses each including said actuator.

3 . The method according to claim 1 , wherein, during said fourth step, a femtosecond laser source is used, mounted on a table with crossing movements or with radial travel, so as to juxtapose different series of fires on different beams with respect to said axis of rotation to create a series of said expansion lines.

4 . The method according to claim 1 , wherein, during said fourth step, a femtosecond laser source is used to perform laser fires in each direction of rotation of said inertial mass.

5 . The method according to claim 1 , wherein, during said fourth step, control means are used to control the fires of said femtosecond laser source, according to the information in respect of presence or absence of material provided by a combination of a detection laser and a collection means.

6 . The method according to claim 1 , wherein, during said first step, said actuator is chosen including, on a first arm a first writing zone, and on a second arm parallel with the first arm along a radial linear direction and joining it at a common segment a second writing zone, said actuator thus being mounted in an “S” between a fastening zone fastened to a support mounted on said inertial mass or directly fastened to said inertial mass, and an exit point or a linking neck for linking with an amplifying mechanism, said actuator being arranged to act in two opposite directions along said linear direction, whereby, during said fourth step, femtosecond laser fire writing takes place in said first writing zone on said first arm for a gain setting, or in said second writing zone on said second arm for a loss setting.

7 . The method according to claim 1 , wherein, during said first step, said actuator is chosen with an exit point or a linking neck for linking with an amplifying mechanism arranged to amplify the exit travel of said actuator, to impart an amplified travel to said inertia-block.

8 . The method according to claim 7 , wherein said amplifier is a parallelogram type, and comprises a connecting rod system with connecting rods arranged between flexible necks forming a linear guidance along a radial linear direction.

9 . The method according to claim 1 , wherein, during said first step, said actuator is chosen including a fastening zone rigidly connected to a support mounted on said inertial mass, and wherein said support forms a one-piece assembly forming a flexible micro-mechanism, with said actuator, the amplifier and said inertia-block mounted in series with each other.

10 . The method according to claim 1 , wherein, during said first step, said actuator is chosen including a fastening zone fastened to a support mounted on said inertial mass or rigidly connected to said support, and wherein said actuator and/or said support is made of glass.

11 . The method according to claim 1 , wherein, during said first step, said inertial mass is a balance, which comprises at least one pair of identical said inertia-blocks diametrically opposed with respect to said axis of rotation.

12 . The method according to claim 1 , wherein, during said first step, said oscillator is incorporated into a watch head of a watch, said watch head including at least one transmissive transparent element, which separates the outside and inside of said watch and enables optical access for at least one laser to at least said inertial mass of said oscillator of the watch.

13 . The method according to claim 1 , wherein, during said first step, said oscillator is equipped with stopping means or a stop-seconds means arranged to bear on said inertial mass, and wherein said fourth step is performed in a locked position of said inertial mass.

14 . The method according to claim 1 , wherein, during said fourth step, said femtosecond laser writing fires are performed during the oscillation of said inertial mass, wherein the angular position and said fires are synchronised.

15 . The method according to claim 1 , wherein, during said fourth step, said fires are performed with a femtosecond laser.

16 . The method according to claim 15 , wherein, during said fourth step, said fires are performed with a femtosecond laser, of wavelength between 900 and 1100 nm, pulse time between 200 and 350 fs, pulse energy approximately between 200 and 300 nJ, repetition frequency of 700 to 900 kHz.

Assignees

• Swatch Group Res & Dev Ltd

Inventors

• Paratte Lionel
• Mouskeftaras Alexandros
• Odeh Ahmad

Classifications

• G04B17/063 Primary

  Balance construction (balances with frequency adjustment screw G04B18/006; balances with temperature compensation G04B17/222; balancing devices G04B17/28) · CPC title

• G04C3/064

  the balance controlling indirectly, i.e. without mechanical connection, contacts, e.g. by magnetic or optic means · CPC title

• G04B18/006

  by adjusting the devices fixed on the balance (construction of the pendulum G04B17/063; balancing G04B17/28) · CPC title

• G04B18/04

  Adjusting the beat of the pendulum, balance, or the like, e.g. putting into beat · CPC title

• G04B15/14 Primary

  Component parts or constructional details, e.g. construction of the lever or the escape wheel {(assembly and manufacture of the spring G04B1/145; assembly and manufacture of components, e.g. pinions, spindles G04B13/02; lubrication of clockwork bearings G04B31/008; oils for clockwork bearings in general G04B31/08)} · CPC title