Touch Watch Glass Electrode Heating for Anti-Fog Control

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Solution Overview

Problem

Existing timepieces, particularly those with touchscreen interfaces, suffer from fog formation on the protective glass due to condensation, which affects user perception of water resistance and brand image, and existing anti-fog solutions are either aesthetically incompatible or have limited absorption capacity.

Innovation Solution

A timepiece with a touch control device incorporating a transparent conductive electrode connected in a closed circuit to an electrical current management module, which generates a controlled electrical current for heating the protective glass to prevent fog formation through the Joule effect, activated by sensors or regular intervals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrophilic coatings are applied to the inner surface of the protective glass to prevent fog formation, then fog prevention is improved, but aesthetic quality deteriorates due to incompatibility with coloration and diffusing effects

Engineering Contradiction:
Improveanti-fog propertyVSAvoidaesthetic quality
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent introduces a transparent conductive electrode as an intermediary element between the protective glass and the fog formation issue. This electrode serves dual purposes: it maintains the aesthetic appearance of the protective glass while providing the necessary electrical conductivity for heating to prevent fog formation, thus resolving the contradiction between anti-fog reliability and aesthetic quality

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state and properties of the protective glass surface by introducing a conductive layer that can be electrically activated. By controlling the electrical parameters (voltage, current) applied to the transparent conductive electrode, the system dynamically adjusts the temperature of the protective glass to prevent condensation while maintaining visual aesthetics

Inventive Principle:
Principle #35Parameter changes

2Reliability

If absorption-based anti-fog solutions are used, then fog prevention is improved to some extent, but the solution becomes time-limited with limited absorption capacity

Engineering Contradiction:
Improveanti-fog propertyVSAvoidduration of anti-fog effect
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent implements periodic heating action through the transparent conductive electrode. The heating element can be activated at regular intervals or continuously to maintain the protective glass temperature above the dew point, ensuring sustained anti-fog effect without the time limitations of absorption-based solutions

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent replaces the passive absorption mechanism with an active thermal field approach. By substituting the mechanical/chemical absorption process with electrical heating, the system achieves indefinite duration of anti-fog protection as long as power is supplied, overcoming the time-limited nature of absorption materials

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

3Adaptability or versatility

If a touchscreen interface is implemented through the protective glass, then user interaction capability is improved, but fog formation becomes more problematic as it obscures the touchscreen functionality

Engineering Contradiction:
Improvetouchscreen functionalityVSAvoidfog on protective glass
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies multi-functionality to the transparent conductive electrode, which serves both as a touch sensor component and as a heating element for fog prevention. This dual-function design ensures that the touchscreen interface remains operational and visible by preventing fog formation, thus resolving the contradiction between adaptability and harmful fog effects

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system incorporates feedback mechanisms where the touch control device and anti-fog device work together. The electronic unit receives signals from the touch sensor and can activate the heating function when condensation is detected or anticipated, ensuring the touchscreen remains usable and visible under varying environmental conditions

Inventive Principle:
Principle #23Feedback

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

Effectively prevents or reduces fog on the protective glass, maintaining aesthetic quality and user confidence by actively managing thermal shocks without user intervention.

Implementation Method 1

heating by Joule effect of said transparent conductive electrode

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4492162B1Timepiece with tactile control comprising an Anti-fogging device
Publication Date: 2026.03.18 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP4492162B1 patent drawingFigure 1~2

AI summary

The invention relates to a timepiece (100) comprising a case (11) forming an electrical mass (15), said case (11) being closed by a base (12) and by a protective glass (13), said timepiece comprising a tactile control device (20) connected to an electronic unit (50) configured to perform at least one predetermined function of said timepiece (100) under the action of the tactile control device (20), said tactile control device (20) comprising at least one capacitive sensor (21) comprising a first armature (Cp1) formed by a transparent conductive electrode (22), provided at least on a portion of an inner face (13.1) of the protective glass (13), and a second armature (Cp2) formed selectively by the positioning of the finger (200) of the wearer of said timepiece (100) on an outer face (13.2) of the protective glass (13); said transparent conductive electrode (22) being electrically connected to said electronic unit (50) by a first electrical conductor (51); characterized in that the timepiece (100) includes an anti-fog device (30) of said protective glass (13) consisting partly of said transparent conductive electrode (22) and a second electrical conductor (52) connecting in a closed circuit said transparent conductive electrode (22) to said electronic unit (50), said electronic unit (50) including an electrical current management module (53) configured to generate a controlled electrical current in the closed circuit allowing heating by Joule effect of said transparent conductive electrode (22).