Watch Hand Illumination via Microstructure Optical Coupling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing watch display technologies rely on fluorescent or phosphorescent coatings for night or dimly lit environments, which are costly and complex to manufacture, and suffer from color mixing issues between hour and minute hands due to the use of UV LEDs.

Innovation Solution

The use of micro-structures for optical coupling between light sources and light guides in watch hands, eliminating the need for fluorescent materials and allowing for simpler manufacturing and color control through the integration of phosphorescent materials or different colored fluorescent pellets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If fluorescent or phosphorescent coatings are used for night illumination, then luminous display is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvenight display luminosityVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the fluorescent/phosphorescent coating layer from the hand structure, replacing it with a simplified alternative illumination mechanism that achieves night display without the complex multi-layer fluorescent structure, thereby reducing manufacturing complexity while maintaining luminous function

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the illumination mechanism from fluorescent/phosphorescent material-based to an alternative optical coupling system, fundamentally altering the physical-chemical parameters of the illumination approach to eliminate the need for complex coating deposition processes

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If UV LEDs are used to excite fluorescent pigments, then night illumination is achieved, but color mixing issues occur between hour and minute hands

Engineering Contradiction:
Improvehand illuminationVSAvoidcolor consistency
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent removes the fluorescent pigment layer that causes color mixing problems when excited by UV LEDs, eliminating the source of color inconsistency between different hands while preserving the night illumination capability through an alternative optical mechanism

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the complex fluorescent pigment system with a simpler, more controllable illumination approach that achieves the desired visual effect without the color mixing issues, using a more straightforward optical coupling mechanism that is easier to control for color consistency

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If openings are made in the hand head to allow light passage, then light transmission to minute hand is enabled, but manufacturing complexity increases

Engineering Contradiction:
Improvelight transmissionVSAvoidhand manufacturing
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent eliminates the need for openings in the hand head by removing the fluorescent coating that required light passage through the hand structure, allowing for a more solid, simpler hand geometry that is easier to manufacture without compromising light transmission functionality

Inventive Principle:
Principle #2Taking out (Extraction)

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 approach reduces manufacturing complexity and cost while providing consistent and controlled lighting effects without color mixing, enabling efficient illumination of watch hands with reduced energy consumption and extended lighting duration.

Implementation Method 1

a first light guide arranged to diffuse part of the light emitted by said at least one light source

Methodology Applied
Scientific EffectLight diffusion: Scattering

Implementation Method 2

first coupling micro-structures arranged to guide light into and/or out of the first light guide

Methodology Applied
Scientific EffectOptical coupling: Refraction

Data Source

PatentEP4478132A1Luminous display of a timepiece by optical coupling via microstructures
Publication Date: 2024.12.18 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP4478132A1 patent drawingFigure 1~3
  • EP4478132A1 patent drawingFigure 4
  • EP4478132A1 patent drawing

AI summary

One aspect of the invention relates to a watch display device (100) (1000) comprising at least one light source (200) and comprising, between a dial (300) carrying at least one reference scale on an upper side (301) and a glass (400) on the user's side, a coaxial switch (10) about an axis of rotation (D) comprising at least one first light indicator (1) comprising a first light guide (11) arranged to diffuse a portion of the light emitted by said at least one light source (200), wherein the first light guide (11) comprises first coupling microstructures (110), which are arranged to make light enter the first light guide (11) and/or to make light exit the first light guide (11).