Light Guide Illuminates Rotating Bezel Index in Diving Watch

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Solution Overview

Problem

Diver's watches face challenges in maintaining readability of the bezel index in low light conditions underwater, as phosphorescent materials require charging and have limited visibility due to smaller surface area and short illumination duration, and integrating a light source in the bezel leads to connection issues and space constraints.

Innovation Solution

Incorporating a light guide in the movable element, such as a rotating bezel, that receives and directs light from a fixed source within the watch case to illuminate the index, regardless of the bezel's position, eliminating the need for mobile light sources and phosphorescent charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If phosphorescent material is used to illuminate the bezel marker, then visibility in low light conditions is improved, but the surface area of the marker remains small compared to hands, limiting visibility underwater

Engineering Contradiction:
Improvevisibility of markerVSAvoidsurface area of marker
Core Design Contradiction:
Illumination intensityVSArea of moving object

Solution Approach 1:

A light guide acts as an intermediary between the light source and the bezel marker. The light guide receives light from the source and directs it to illuminate the marker, enabling effective illumination without requiring the marker itself to be large or contain phosphorescent material.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/phosphorescent illumination system with an optical system using a light guide. Instead of relying on phosphorescent materials that require charging and have limited duration, the system uses a light guide to direct light from a source to the marker, providing sustained illumination.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Illumination intensity

If phosphorescent elements are used to illuminate the marker, then visibility is improved, but the illumination duration is limited and intensity decreases over time

Engineering Contradiction:
Improvevisibility of markerVSAvoidillumination duration
Core Design Contradiction:
Illumination intensityVSDuration of action of moving object

Solution Approach 1:

The light guide enables continuous illumination by continuously directing light from the source to the marker. Unlike phosphorescent materials that deplete their charge over time, the light guide system can maintain steady illumination as long as the light source remains active, providing uninterrupted visibility.

Inventive Principle:
Principle #20Continuity of useful action

3Illumination intensity

If a light source is integrated within the rotating bezel, then illumination of the index is achieved, but connection problems with the power supply occur and space constraints are created

Engineering Contradiction:
Improveillumination of indexVSAvoidconnection problems and space constraints
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light guide serves as an intermediary that allows the light source to remain stationary in the watch case while still illuminating the moving bezel marker. This eliminates the need for complex moving connections between the power supply and light source, as the light guide moves with the marker rather than the light source.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of placing the light source in the moving bezel (which creates connection problems), the patent inverts the approach by placing the light source in the stationary case and using a light guide in the moving element to deliver light to the marker. This reversal eliminates the connection complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

4Illumination intensity

If the light source moves with the bezel, then illumination is maintained, but connection problems with the fixed power supply occur

Engineering Contradiction:
Improveillumination of markerVSAvoidconnection reliability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The light guide acts as an intermediary that decouples the light source from the moving bezel. The stationary light source connects reliably to the fixed power supply, while the light guide moves with the bezel to maintain illumination of the marker, separating the reliability-critical connection from the moving parts.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Ensures consistent illumination of the index in low light conditions without prior charging, avoiding connection problems and space constraints, while maintaining readability underwater.

Implementation Method 1

the guide being configured to receive a light beam from the light source through an inlet face, and to guide light rays through an outlet face of the light guide in order to illuminate the index

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

guide light rays through an outlet face of the light guide

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3667436B1Timepiece including a mobile element provided with a light spot
Publication Date: 2022.05.04 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP3667436B1 patent drawingFigure 1~2
  • EP3667436B1 patent drawingFigure 3~5
  • EP3667436B1 patent drawingFigure 6~8

AI summary

The invention relates to a timepiece (1), in particular a diving watch, comprising a case (2) with a case middle (3), a light source (6), a movable element (4) between several positions relative to the case (2), and movable means for attaching the movable element (4) to the case middle (3) of the case (2). More particularly, the movable element (4) comprises a light guide (10) and an upper cover (9) having an index (5), the guide (10) being configured to receive a light beam (8) from the light source through an inlet face (12), and to guide light rays (18) through an outlet face (15) of the light guide (10) in order to illuminate the index (5), regardless of the position of the movable element (4) relative to the case (2).