Horological Oscillator Frequency Tuning by Laser Micro-Expansion
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Solution Overview
Problem
Existing methods for adjusting the frequency of mechanical horological oscillators, such as watch balances, require disassembly and reassembly, leading to inaccuracies and mechanical play, resulting in drifts of up to 10 seconds per day, which is undesirable for precision timekeeping.
Innovation Solution
A method using femtosecond laser excitation to induce permanent mechanical tension in a flexible mechanism embedded on the oscillator, allowing for fine adjustments of the oscillator's frequency without disassembly by modifying the inertia through local micro-expansion of materials like glass, utilizing optomechanical actuators to move inertia-blocks radially.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mechanical adjustment methods are used to modify frequency, then the oscillator can be adjusted, but the watch must be disassembled and reassembled causing drift of up to 10 seconds per day
Solution Approach 1:
The patent replaces traditional mechanical adjustment methods with optical laser technology. Femtosecond laser pulses are used to induce permanent mechanical tension in a flexible mechanism embedded on the oscillator, causing local micro-expansion of glass material. This optomechanical approach eliminates the need for disassembly and reassembly, preventing mechanical play and drift while achieving precise frequency adjustments within 0-2 seconds per day.
Solution Approach 2:
The patent changes the physical state of the glass material through laser-induced micro-expansion. By applying femtosecond laser pulses to specific writing zones in the glass flexible mechanism, the material undergoes permanent local expansion that permanently alters the mechanical tension and stiffness of the elastic return means, thereby precisely adjusting the oscillator frequency without mechanical contact.
2Adaptability or versatility
If mechanical adjustment devices are used, then frequency can be modified, but mechanical play causes drift once setting force is removed
Solution Approach 1:
The patent replaces mechanical adjustment devices with an optomechanical system using femtosecond laser pulses. The laser induces permanent structural changes in the glass flexible mechanism through photoelastic effects, creating stable mechanical tension without moving parts. This eliminates mechanical play and hysteresis while maintaining frequency adjustability, achieving stability within 0-2 seconds per day.
Solution Approach 2:
The patent utilizes phase transitions in glass material at the micro-scale through femtosecond laser heating. The laser pulses create localized thermal zones that induce permanent micro-expansion and structural changes in the glass, transitioning the material from its initial state to a permanently deformed state with altered mechanical properties, thereby stabilizing the frequency adjustment.
3Manufacturing precision
If disassembly and reassembly is performed for frequency adjustment, then the oscillator can be tuned, but accuracy is compromised due to mechanical play
Solution Approach 1:
The patent replaces mechanical disassembly and reassembly with a non-contact optical method. Femtosecond laser pulses are focused through a transparent element in the watch case to directly modify the glass flexible mechanism embedded on the oscillator. This optomechanical approach achieves manufacturing precision of 0-2 seconds per day by eliminating the mechanical play and distortion introduced by traditional disassembly and reassembly operations.
Solution Approach 2:
The patent introduces a transparent element in the watch case as an optical intermediary that allows laser beams to pass through and reach the oscillator components without opening the case. This intermediary enables precise frequency tuning through the glass flexible mechanism while maintaining the sealed integrity of the watch, preventing the accuracy loss associated with mechanical disassembly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise frequency adjustments of up to 0-2 seconds per day with high positioning precision and zero hysteresis, maintaining the oscillator's integrity and accuracy without mechanical play.
Implementation Method 1
femtosecond laser excitation to induce permanent mechanical tension in a flexible mechanism embedded on the oscillator, allowing for fine adjustments of the oscillator's frequency without disassembly by modifying the inertia through local micro-expansion of materials like glass
Implementation Method 2
The actuator 35 is made of a material suitable for irreversible local micro-expansion under the action of laser fires
Data Source
AI summary
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.