Silicon Watch Component Coating to Prevent Debris Scattering

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Solution Overview

Problem

Silicon watch components are fragile and prone to breakage, leading to the scattering of debris within the watch movement, which compromises the functionality and cleanliness of the mechanism.

Innovation Solution

A multi-layer coating comprising elastic and more resistant materials is applied to the surface of the watch component, particularly in areas subjected to tensile stress, to prevent debris scattering and enhance structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a silicon watch component is manufactured using deep etching technique, then micrometric precision is achieved, but the component becomes fragile with wrinkled sides that weaken mechanical resistance

Engineering Contradiction:
Improvemicrometric precisionVSAvoidmechanical resistance
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent applies a multi-layer coating system consisting of elastic material layers (polymer or metal) combined with resistant material layers (oxide or nitride). This composite structure combines the flexibility and stress-absorbing capability of the elastic layers with the hardness and wear resistance of the resistant layers, thereby maintaining manufacturing precision while significantly improving mechanical resistance and reducing fragility.

Inventive Principle:
Principle #40Composite materials

2Shape

If a silicon watch component is cut from a silicon substrate using deep etching, then the component shape is defined, but surface flatness defects in the form of ripples are generated that weaken mechanical resistance

Engineering Contradiction:
Improvecomponent shapeVSAvoidmechanical resistance
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent employs a multi-layer coating that includes elastic material layers acting as flexible shells surrounding the silicon component. These elastic layers can accommodate surface irregularities and ripple defects without transmitting stress concentrations to the base material, thereby maintaining the defined component shape while preventing the ripple-induced weakening of mechanical resistance.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If a silicon watch component breaks, then the watch movement stops functioning, but a significant amount of silicon debris is scattered within the watch movement

Engineering Contradiction:
Improvewatch functionalityVSAvoiddebris scattering
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The multi-layer coating system acts as a containment structure that binds together fragments of the silicon component upon breakage. The elastic material layers provide flexibility to absorb impact energy, while the resistant material layers provide structural integrity to hold fragments together, thereby preventing debris scattering and maintaining watch movement functionality even when the component fails.

Inventive Principle:
Principle #40Composite materials

4Strength

If a multi-layer coating with elastic and resistant materials is applied to the watch component, then tensile strength is significantly increased, but the device complexity increases

Engineering Contradiction:
Improvetensile strengthVSAvoidcoating structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent divides the protective coating into multiple distinct layers with specific functions: elastic material layers for stress absorption and resistant material layers for hardness and wear resistance. This segmentation allows each layer to be optimized independently for its specific function, achieving high tensile strength while keeping the overall structure manageable through functional division rather than a single complex layer.

Inventive Principle:
Principle #1Segmentation

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 coating significantly increases the tensile strength of the watch component, minimizing debris scattering and optimizing resistance, with an average resistance exceeding 6000 MPa, while maintaining micrometric precision and flexibility.

Implementation Method 1

a multi-layer coating comprising at least two layers of elastic material separated by a layer of material more resistant than the elastic material

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

Such a coating forms a protective layer for the watch component to prevent the scattering of debris in the event of breakage of the component by holding the different pieces together

Methodology Applied
Scientific EffectComposite material strengthening: Composite Materials

Data Source

PatentEP3798739B1Timepiece component
Publication Date: 2025.07.02 ROLEX SA
  • EP3798739B1 patent drawingFigure 1~2
  • EP3798739B1 patent drawingFigure 3~4
  • EP3798739B1 patent drawingFigure 5

AI summary

Watch component based on a brittle material characterized in that it comprises at least a surface part of brittle material covered by a coating (10) comprising at least two CE layers of elastic material (11) separated by a CR layer of material more resistant (12) than the elastic material (11).