Capacitive Dongle for Touch Displays

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Solution Overview

Problem

In applications like aircraft dashboards where display devices are densely packed, traditional electrical connections are cumbersome, and wireless links face interference issues, making it difficult to efficiently communicate with capacitive touch surfaces without hardware modifications.

Innovation Solution

A capacitive dongle that operates on a capacitive touch surface by transmitting and receiving signals at specific frequencies, using a ring-shaped conductive metal part and suction cup for placement, enabling communication without substantial hardware changes, and employing envelope detection and synchronous demodulation for data exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional electrical connections are used to communicate with display devices, then reliable data exchange is achieved, but the arrangement becomes cumbersome and complicates the dashboard layout

Engineering Contradiction:
Improvedata exchange reliabilityVSAvoiddashboard arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical electrical connection system with a capacitive coupling system. The dongle uses a conductive element that couples capacitively to the touch surface conductors, eliminating the need for physical electrical connectors and wires, thereby simplifying the dashboard arrangement while maintaining communication reliability

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

Solution Approach 2:

The touch surface itself serves as an intermediary medium for data transmission. Instead of direct electrical connections between devices, the capacitive touch surface acts as a communication channel, allowing data exchange through capacitance variations detected by the dongle

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If wireless links are used to communicate with display devices, then installation simplicity is improved, but radioelectric interference occurs which is incompatible with aeronautical use

Engineering Contradiction:
Improveinstallation simplicityVSAvoidradioelectric interference
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the electromagnetic wireless communication system with a capacitive coupling system that uses electrical fields at low frequencies. This substitution eliminates radioelectric interference while maintaining the installation simplicity of wireless links, making it suitable for aeronautical environments

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

3Device complexity

If capacitive detection is used for communication, then hardware modifications are minimized, but the dongle requires stable placement on the touch surface

Engineering Contradiction:
Improvehardware modification complexityVSAvoiddongle placement stability
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The dongle incorporates its own suction cup mechanism that automatically creates a secure attachment to the touch surface. This self-service feature eliminates the need for external mounting mechanisms or manual stabilization, allowing the dongle to maintain stable placement autonomously

Inventive Principle:
Principle #25Self-service

4Area of stationary object

If the entire touch surface is used for display, then display area is maximized, but adding connectors underneath complicates the arrangement

Engineering Contradiction:
Improvedisplay areaVSAvoidconnector arrangement complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical connector system with a capacitive coupling system that requires no physical connectors underneath the display. The conductive element of the dongle couples capacitively to the touch surface conductors, allowing data exchange without any hardware modifications to the display背面, thus maintaining maximum display area

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

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

Enables seamless communication with capacitive touch devices by recognizing the dongle's profile and switching to dedicated frequencies, allowing for efficient data exchange without the need for additional hardware or complex arrangements, while minimizing interference and maintaining surface usability.

Implementation Method 1

a suction cup device for holding the dongle in place on the capacitive touch surface

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

a ring-shaped flat conductive metal part connected to said emitting means, said part intended to be placed on said capacitive touch surface

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2891947B1Capacitive dongle for display devices comprising a capacitive touch-sensitive surface
Publication Date: 2022.05.04 THALES SA
  • EP2891947B1 patent drawingFigure 1~2
  • EP2891947B1 patent drawingFigure 3~4
  • EP2891947B1 patent drawingFigure 5~6

AI summary

The general field of the invention is that of capacitive dongles (200) used with display devices comprising a capacitive touch surface including a matrix (110) of conductive rows and columns, the dongle being disposed on said touch surface in functional use, the dongle operating in transmit and receive modes. The dongle according to the invention comprises: - means for transmitting (230, 240) analog periodic signals emitted at a specific frequency referred to as the "dongle frequency"; - a flat, ring-shaped, conductive metal piece (210) connected to said transmitting means, said piece intended to be placed on said touch surface; - means for receiving (250, 260) the signals received from said conductive metal piece; - means for analyzing (270, 280, 290) said digitized received signals; - means for storing the transmitted and analyzed signals; - a digital communication interface (295).