Watch Component Zinc-Based Interference Optical System

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Solution Overview

Problem

Existing decorative methods for watch components, such as those using physical vapor deposition, fail to provide a predictable and reproducible optical layer, limiting the variety of colors that can be achieved, especially when using copper-based materials.

Innovation Solution

A watch component with an interference optical system comprising a zinc-based absorption layer under a transmission layer, obtained by atomic layer deposition, which allows for precise modulation of reflected light and a wide range of colors by adjusting the nature and thickness of the transmission layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If physical vapor deposition is used to deposit a transparent layer, then the layer can be deposited on the article, but the irregular thickness prevents obtaining a predictable and reproducible optical layer

Engineering Contradiction:
Improvethickness uniformityVSAvoidreproducibility of optical layer
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the deposition method from physical vapor deposition to atomic layer deposition, fundamentally altering the process parameters to achieve uniform thickness. The ALD method uses sequential surface reactions with precise control of precursor exposure and reaction conditions, enabling thickness uniformity of ±1 nm and reproducible optical properties.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If only a transparent layer is deposited to give vitreous white porcelain appearance, then the basic decorative effect is achieved, but no interference effect can be obtained and precise color selection is limited

Engineering Contradiction:
Improvecolor varietyVSAvoidcolor precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent segments the optical layer into multiple functional sub-layers: a first transparent layer (50-200 nm) providing base transparency and a second transparent layer (50-200 nm) providing interference effects. This segmentation allows independent optimization of each layer's function, achieving both vitreous appearance and precise color modulation through interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a composite optical structure combining two different transparent materials with specific thicknesses. The first layer has thickness t1 and the second layer has thickness t2, where the combination produces interference effects that enable precise color selection while maintaining the vitreous appearance, achieving both decorative and optical precision.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If atomic layer deposition is used to deposit a protective layer, then uniform thickness is achieved, but the variety of colors achievable by varying material and thickness is insufficient

Engineering Contradiction:
Improvethickness uniformityVSAvoidcolor variety
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adjustability in the optical system by allowing independent variation of the first transparent layer thickness (t1: 50-200 nm) and second transparent layer thickness (t2: 50-200 nm). This dynamic control enables precise modulation of interference patterns and color output, achieving a wide variety of colors while maintaining ALD-deposited thickness uniformity.

Inventive Principle:
Principle #15Dynamics

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 interference optical system enables the component to be selectively decorated with very precise shades of color, achieving high interference visibility and contrast over the human visible spectrum, independent of the underlying material, allowing for precise color modulation without material-dependent limitations.

Implementation Method 1

the absorption layer absorbs light over the entire visible spectrum (for the part of the light transmitted at the transmission layer-absorption layer interface)

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

It is by interference phenomenon through the transmission layers that the color is modulated from the partially reflected light

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 3

at least one transmission layer formed based on an oxide, a carbide, a sulphide or a nitride which is obtained by an ALD method

Methodology Applied
Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Data Source

PatentEP3896192A1Timepiece component with an improved interferential optical system comprising a zinc-based layer
Publication Date: 2021.10.20 RICHEMONT INTERNATIONAL SA
  • EP3896192A1 patent drawingFigure 1~2
  • EP3896192A1 patent drawingFigure 3~4
  • EP3896192A1 patent drawingFigure 5~6

AI summary

The invention relates to a watch component (1) formed of a body (10) made of a material to be decorated, which is at least partially covered with at least one interference optical system (40). The latter comprises at least one transmission layer (30) made of an oxide, carbide, sulfide, or nitride, obtained by an ALD method, in order to at least partially transmit ambient light to modify the visual appearance of the watch component (1). According to the invention, the interference optical system (40) further comprises a zinc-based absorption layer (20) mounted beneath the transmission layer (30) in the visible human spectrum, thereby improving the accuracy of the colors obtained by the interference optical system (40).