Coloured Thermocompensated Spiral Coil Spring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for coloring coil springs in mechanical watches are not compatible with the requirements of magnetic insensitivity and thermal compensation, which are essential for the component's functionality and aesthetic appeal.
Innovation Solution
A method involving the formation of a thin silicon oxide film on the coil spring's core, where one face is colored through an interference effect and the other faces receive a thicker thermal compensation layer, allowing for color selection and maintaining the component's functional specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thick layer of silicon oxide is deposited on all faces of the coil spring for thermal compensation, then thermal stability is improved, but the aesthetic appearance and color visibility are worsened
Solution Approach 1:
The patent applies different thicknesses of silicon oxide layer to different faces of the coil spring. Faces requiring thermal compensation receive a first thickness (e.g., 1-10 μm), while faces requiring color visibility receive a second, smaller thickness (e.g., 0.1-1 μm) to produce interference colors. This local differentiation allows each face to optimize its specific function.
Solution Approach 2:
The coil spring surface is segmented into functionally distinct zones: thermal compensation zones with thicker oxide layers and aesthetic display zones with thinner oxide layers. This segmentation enables independent optimization of thermal performance and visual appearance on different portions of the same component.
2Illumination intensity
If a thin layer of silicon oxide is deposited on the coil spring face for coloration, then aesthetic appearance is improved, but thermal compensation capability is worsened
Solution Approach 1:
The patent applies different thicknesses of silicon oxide layer to different faces of the coil spring. Faces requiring thermal compensation receive a first thickness (e.g., 1-10 μm), while faces requiring color visibility receive a second, smaller thickness (e.g., 0.1-1 μm) to produce interference colors. This local differentiation allows each face to optimize its specific function.
3Illumination intensity
If conventional coloring methods (PVD, ALD, galvanic processes, anodisation) are applied to the coil spring, then aesthetic appearance is improved, but magnetic insensitivity and thermal compensation specifications are worsened
Solution Approach 1:
The patent changes the deposition parameters of the silicon oxide layer, specifically controlling the thickness to be in the range of 0.1-1 μm for colored faces. This parameter control enables the same material (silicon oxide) to serve both aesthetic and functional purposes, unlike conventional coloring methods that use different materials.
Solution Approach 2:
The patent uses a composite structure where the silicon oxide layer serves dual functions: as a thermal compensation layer when thick, and as an optical interference layer when thin. This multi-functional use of a single material system avoids the conflicts associated with conventional multi-layer approaches.
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
The method allows for visible coloration of the coil spring while ensuring minimal impact on its operational behavior and thermal compensation, providing a range of colors with minimal disruption to the production process and functionality.
Implementation Method 1
forming a thin film on at least one face of the core of the coil spring creating a colour on said face as the result of an interference effect
Implementation Method 2
the film is a silicon oxide (SiO2) film which contributes with other faces covered by a thicker layer of silicon oxide to the thermal compensation of the coil spring
Data Source
AI summary
A method for producing a thermocompensated and coloured coil spring including the steps of forming a first layer of silicon oxide on at least one face of the core and on at least one other face of the core, the first layer having a thickness equal to a fraction of the thickness required for achieving thermal compensation, removing the first layer from at least one face of the core, forming a second layer of silicon oxide on at least one face of the core and on at least one other face of the core, the second layer having a thickness equal to the remaining fraction of the thickness required for achieving thermal compensation which is lower than or equal to 1 μm for giving at least one face of the core a colour as a result of the interference effect.