One-Piece Silicon Double Balance Spring for Timepiece Temperature Stability

The patent merges two separate balance springs into a single integrated component where the collet is formed as one piece with both balance springs. This is achieved through a multi-layer silicon-based material structure where the collet has approximately the same section in each layer, allowing the springs to be coaxially mounted and integrated without separate assembly steps, thereby resolving the assembly difficulty while maintaining temperature stability.

The patent employs silicon-based materials with specific thermo-elastic coefficients to achieve temperature stability. The use of silicon-based materials allows for controlled thermal expansion properties while enabling the complex one-piece structure to be manufactured through selective etching processes, simultaneously addressing both temperature stability and manufacturing feasibility.

The patent segments the manufacturing process into distinct layers (first layer, second layer, third layer) that are selectively etched to form different components. The collet is formed by etching through multiple layers, with each layer contributing a portion of the final structure. This segmentation allows complex three-dimensional features to be created through sequential two-dimensional etching operations, reducing the overall manufacturing precision requirement compared to creating the entire structure in a single operation.

The patent transitions from two-dimensional etching operations to three-dimensional structure formation by stacking multiple etched layers. The collet extends through multiple layers with varying cross-sections, creating a complex 3D geometry through sequential 2D processing steps. This dimensional approach allows the one-piece design to be manufactured with standard precision etching equipment rather than requiring ultra-precise 3D manufacturing.

The patent uses silicon-based materials that can be oxidized to form silicon dioxide, creating a composite structure with enhanced mechanical properties. The oxidation process transforms the silicon surface into a harder, more mechanically resistant silicon dioxide layer while maintaining the underlying silicon structure's temperature stability characteristics. This composite approach allows simultaneous achievement of thermal stability and mechanical strength.

The patent modifies the physical and chemical parameters of the silicon-based material through oxidation treatment. By controlling the oxidation process, the material's surface properties are changed to increase mechanical resistance while the bulk material retains its temperature stability. This parameter change allows the same base material to exhibit different property profiles in different regions and under different conditions.