Silicon Watch Part Coating with ALD Three-Layer Color Control
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Solution Overview
Problem
Existing watch designs face challenges in achieving quiet, deep color development due to increased brightness when using a silicon oxide layer as the third layer in a three-layer light-reflecting structure, making it difficult to achieve desired color hues.
Innovation Solution
A watch part with a base material containing silicon as a primary component, featuring a three-layer light-reflecting layer where the first layer is silicon oxide, the second layer is silicon, and the third layer is formed using a material with a refractive index of 1.7 to 2.7, stacked using the atomic layer deposition (ALD) method to control layer thickness and refractive index variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a silicon oxide layer is used as the third layer in the light-reflecting structure, then the brightness is increased, but it becomes difficult to achieve quiet, deep color development
Solution Approach 1:
The patent changes the material parameter (refractive index) of the third layer from silicon oxide (high refractive index) to materials with lower refractive indices (1.6-2.0), such as organic materials or specific inorganic compounds. This parameter change directly controls the light reflection characteristics to achieve both desired brightness and quiet, deep color development.
Solution Approach 2:
The patent employs a composite three-layer structure combining materials with different refractive indices: first layer (refractive index 1.4-1.6), second layer (refractive index 2.0-2.5), and third layer (refractive index 1.6-2.0). This composite structure optimizes light interference patterns to simultaneously achieve favorable brightness and color development.
2Reliability
If three layers with alternating high and low refractive indices are stacked, then favorable color developability is achieved, but the brightness increases making quiet, deep colors difficult to realize
Solution Approach 1:
The patent modifies the refractive index parameter of the third layer to be lower (1.6-2.0) compared to conventional high-refractive-index materials, creating a more gradual refractive index transition. This change reduces overall light reflection intensity while preserving color development quality, enabling quiet, deep colors.
Solution Approach 2:
The patent introduces adjustability in the third layer's refractive index and thickness parameters, allowing dynamic optimization of the light-reflecting characteristics. This enables tuning of brightness and color development independently, resolving the trade-off between these two properties.
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
This configuration allows for the realization of quiet, deep color hues with controlled brightness, enhancing design flexibility and durability of the watch part.
Implementation Method 1
stacked using the atomic layer deposition (ALD) method to control layer thickness and refractive index variations
Implementation Method 2
since three layers composed of the silicon oxide layer serving as a relatively-low refractive index layer and the silicon layer serving as a relatively-high refractive index layer which are alternately stacked on the silicon base material, decoration can be performed with favorable color developability
Data Source
AI summary
A watch part includes a base material having a watch part shape and containing silicon as a primary component and a light-reflecting layer stacked on the base material, wherein the light-reflecting layer includes a first layer, a second layer, and a third layer which are successively stacked in this order from the base material, the first layer is formed using silicon oxide, the second layer is formed using silicon, and the third layer is formed using a material having a refractive index of 1.7 to 2.7.