Silicon Watch Escape Wheel with Three-Layer Reflective Coating
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Solution Overview
Problem
Watch components, particularly those inside mechanical watches with see-through structures, lack sufficient decorativeness and require enhanced visual appeal from both the dial and case back sides, while existing materials and manufacturing methods do not effectively achieve the desired level of reflectivity and durability.
Innovation Solution
A watch component featuring a base member made of silicon with a three-layer light reflecting layer structure, comprising a first silicon oxide layer, a silicon layer, and a second silicon oxide layer, applied using thermal oxidation and low-pressure CVD methods, which provides high reflectance and durability, and can be strategically positioned on surfaces and sides to enhance visibility and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer silicon oxide coating is applied to silicon base member, then the manufacturing process is simple, but the reflectance and decorativeness are insufficient
Solution Approach 1:
The light reflecting layer is divided into three distinct sub-layers: a first silicon oxide layer, a silicon layer, and a second silicon oxide layer. Each layer serves specific optical functions, with the first silicon oxide layer providing initial reflection, the silicon layer enhancing reflectance through its crystalline structure, and the second silicon oxide layer providing additional reflection and protection. This segmentation allows the total reflectance to exceed 50% across the visible spectrum, significantly improving decorativeness compared to single-layer coatings.
Solution Approach 2:
The invention uses a composite structure combining different forms of silicon (amorphous silicon oxide and crystalline silicon) in a layered configuration. The first silicon oxide layer has refractive index n1, the silicon layer has refractive index n2, and the second silicon oxide layer has refractive index n3, where n1 < n2 > n3. This composite material approach creates constructive interference of reflected light waves, maximizing reflectance across the visible spectrum while maintaining manufacturing feasibility through sequential deposition processes.
2Weight of moving object
If silicon base member is used for watch components, then weight is reduced and processability is improved, but decorativeness of internal components is insufficient
Solution Approach 1:
The three-layer light reflecting layer structure creates iridescent color effects through optical interference. By controlling the thickness parameters (66-86 nm for silicon layer, 100-400 nm for first silicon oxide layer, and appropriate thickness for second silicon oxide layer), the structure reflects specific wavelengths of visible light, producing vibrant colors that change with viewing angle. This provides the desired decorativeness for internally visible watch components while maintaining the weight advantages of silicon materials.
3Illumination intensity
If light reflecting layer is applied to enhance decorativeness, then visual appeal is improved, but manufacturing complexity increases
Solution Approach 1:
The invention specifies precise parameter ranges for each layer thickness to achieve optimal optical performance within manufacturable tolerances. The silicon layer thickness is controlled at 66-86 nm, the first silicon oxide layer at 100-400 nm, and the second silicon oxide layer at appropriate thickness. These parameter specifications allow standard semiconductor manufacturing equipment to produce the required optical effects without requiring complex custom processes, balancing decorativeness with manufacturing simplicity.
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 solution achieves excellent decorativeness and durability by ensuring high reflectance and protection, allowing for favorable coloring and reduced distortion, thus enhancing the visual appeal and mechanical integrity of watch components like the escape gear wheel.
Implementation Method 1
a light reflecting layer provided at the first surface of the base member, the light reflecting layer having a three-layer structure in which a first silicon oxide layer, a silicon layer, and a second silicon oxide layer are layered in this order
Implementation Method 2
a light reflecting layer having a three-layer structure in which a first silicon oxide layer, a silicon layer, and a second silicon oxide layer are layered in this order... a maximum reflectance for light having a wavelength in a range from 400 nm to 780 nm when the light is incident on the light reflecting layer at an incident angle of 0° may be 50% or greater
Implementation Method 3
at least one of the first silicon oxide layer and the second silicon oxide layer may be formed by a thermal oxidation method
Implementation Method 4
the silicon layer may be formed by a low-pressure CVD method
Data Source
AI summary
For example, an escape gear wheel part as a watch component includes a base member including a first surface and a second surface opposite the first surface, the base member being mainly composed of silicon, and a light reflecting layer provided at the first surface of the base member, the light reflecting layer having a three-layer structure in which a first silicon oxide layer, a silicon layer, and a second silicon oxide layer are layered in this order.