Bezel Touch Interface for Wearable Displays

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Solution Overview

Problem

Tactile interfaces on watch crystals compromise visibility of information and are costly to produce due to the complexity of applying metal layers like ITO on substrates.

Innovation Solution

A portable electronic object with tactile control means featuring flexible printed circuits on polyimide substrates with conductive electrodes, allowing for simpler and less expensive production, and placement on the bezel rather than the crystal for improved usability and visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a capacitive touch interface is implemented on the crystal using ITO metal layer deposition, then the tactile control function is achieved, but the manufacturing complexity and cost increase significantly

Engineering Contradiction:
Improvetactile control functionVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the touch interface from the crystal substrate and relocates it to the bezel. This separates the tactile control function from the display crystal, allowing the use of simpler, less expensive materials and manufacturing processes for the touch interface while preserving the crystal's optical functions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the expensive ITO metal layer deposition process with a cheaper alternative using conductive paint or conductive polymer coatings on the bezel. This substitution significantly reduces manufacturing cost and complexity while achieving the same capacitive touch functionality.

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

2Ease of operation

If a capacitive touch interface is implemented on the crystal, then the tactile control function is achieved, but the visibility of displayed information is reduced due to finger contact

Engineering Contradiction:
Improvetactile control functionVSAvoidvisibility of information
Core Design Contradiction:
Ease of operationVSIllumination intensity

Solution Approach 1:

The patent extracts the touch interface from the crystal surface and relocates it to the bezel. This separation allows the crystal to remain clear and transparent for optimal information visibility, while the bezel handles all user interaction through capacitive touch, eliminating the trade-off between tactile control and visibility.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If an ITO metal layer is deposited on the crystal substrate, then the capacitive touch function is achieved, but the manufacturing cost increases

Engineering Contradiction:
Improvecapacitive touch functionVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive ITO metal layer deposition process with cheaper alternative materials such as conductive paint, conductive polymer coatings, or carbon-based conductive materials applied to the bezel. These alternatives achieve the same capacitive touch functionality at significantly reduced manufacturing cost.

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

Solution Approach 2:

By extracting the touch interface from the crystal and placing it on the bezel, the patent eliminates the need for expensive ITO deposition on the crystal. The bezel can use simpler, less costly conductive materials while maintaining the capacitive touch function.

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

The solution provides a cost-effective, flexible, and user-friendly touch-sensitive interface that maintains visibility of information without the need for complex metal layer deposition on the crystal, enhancing interactivity and reducing manufacturing costs.

Implementation Method 1

This contact causes the appearance of an additional capacitance which forms between said electrode and the finger which is an electrically conductive element. This capacitance variation is detected by the electronic watch movement

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

said electrode being electrically connected to the control circuit by a conductive track

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2884353B1Touch-sensitive portable electronic object
Publication Date: 2018.01.31 ETA SA MFG HORLOGERE SUISSE
  • EP2884353B1 patent drawingFigure 1
  • EP2884353B1 patent drawingFigure 2~3
  • EP2884353B1 patent drawingFigure 4~6

AI summary

The present invention relates to a portable electronic object (1) equipped with a case (10) comprising a frame (11) closed by a base and by a glass (13) and a bezel (14) fixed to the frame, said case enclosing at least one electronic module (20) consisting of a printed circuit board (22) on which is fixed at least one microcontroller (23) sending information to display means (30), said object further comprising tactile control means (50) comprising at least one support (51) on which at least one electrode (52) is arranged, said electrode being electrically connected to the microcontroller by a conductive track (53).