Timepiece Decorative Member With Iridescent Luminous Patterning

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Solution Overview

Problem

There is a demand for further improving design properties in decorative members for timepieces.

Innovation Solution

A decorative member for a timepiece comprising a light-transmitting member with a dielectric multilayer film, a light-blocking layer, a first printed layer of light-transmitting paint, and a second printed layer with a high light-blocking property, where the first printed layer can be luminous paint, and the dielectric multilayer film has thin films with varying refractive indices to create different color tones depending on the line of sight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a color film and luminous paint are applied to a transparent cover glass as in Patent Literature 1, then the decorative member has basic design properties, but the design properties are insufficient and lack visual appeal in various lighting conditions

Engineering Contradiction:
Improvedesign propertiesVSAvoidvisual appearance in different lighting conditions
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies a composite structure consisting of a dielectric multilayer film with specific refractive indices (TiO2 with n=2.4 and SiO2 with n=1.46), a light-blocking layer, and luminous paint layers. This composite structure creates iridescent effects and maintains pattern visibility in both light and dark conditions, resolving the insufficiency of basic color film designs.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The dielectric multilayer film is designed to produce iridescent color effects through interference of light waves. The specific combination of high and low refractive index layers creates wavelength-dependent reflection, causing the decorative member to display different colors and tones depending on the viewing angle and lighting conditions, thereby enhancing adaptability.

Inventive Principle:
Principle #32Color changes

2Manufacturing precision

If multiple layers are added to improve design properties, then aesthetic appeal increases, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveaesthetic appealVSAvoidmanufacturing process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The manufacturing process is segmented into distinct sequential steps: forming the dielectric multilayer film on the transparent member, applying the light-blocking layer, creating the pattern by removing portions of these layers, and applying luminous paint in multiple coats. This segmentation allows each layer to be optimized independently while maintaining overall manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dielectric multilayer film and light-blocking layer are formed and patterned before applying the luminous paint. This preliminary preparation ensures that the underlying optical structure is established first, allowing the paint application to focus solely on adding luminous properties without complicating the overall process.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If a simple single-layer structure is used, then manufacturing is easier, but the decorative pattern is not easily visible in both light and dark conditions

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpattern visibility in light and dark
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses a composite structure with a dielectric multilayer film for iridescent effects, a light-blocking layer for pattern definition, and luminous paint for visibility in dark conditions. This composite approach maintains relative manufacturing simplicity while achieving dual-condition visibility through the synergistic combination of layers with different optical properties.

Inventive Principle:
Principle #40Composite materials

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 decorative member achieves excellent design properties with the decorative pattern being easily visible in both light and dark conditions, enhancing aesthetic appeal.

Implementation Method 1

the dielectric multilayer film is preferably formed by laminating thin films; and the thin films preferably includes a first thin film having a first refractive index and a second thin film having a second refractive index different from the first refractive index

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 2

the paint forming the first printed layer is preferably luminous paint

Methodology Applied
Scientific EffectLuminescence: Luminescence

Data Source

PatentEP4685580A1Decorative member for timepiece, and method for manufacturing same
Publication Date: 2026.01.28 CITIZEN WATCH CO LTD
  • EP4685580A1 patent drawingFigure 1
  • EP4685580A1 patent drawingFigure 2
  • EP4685580A1 patent drawingFigure 3

AI summary

A decorative member for a timepiece having excellent design properties is provided. The decorative member for a timepiece includes a light-transmitting member, a dielectric multilayer film covering one surface of the light-transmitting member and having an opening representing a predetermined pattern, a light-blocking layer covering the dielectric multilayer film, a first printed layer formed of light-transmitting paint and covering the opening of the dielectric multilayer film, and a second printed layer covering the first printed layer.