Capacitive Sensor Tamper-Proof Signal Generation

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Solution Overview

Problem

Existing capacitive touch systems lack a secure and intuitive method for generating tamper-proof time-dependent signals, relying on geometric coding and direct contact with conductive structures, which are not universally applicable and can be manipulated.

Innovation Solution

A device with an electrically conductive structure on a non-conductive substrate generates static signals on a capacitive area sensor, which are converted into dynamic signals through additional input, creating a complex and tamper-proof time-dependent signal without direct contact, utilizing the capacitive surface sensor's electrode grid for indirect interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If geometric coding with direct contact conductive structures is used, then the capacitive sensor can detect the signal, but the system is vulnerable to manipulation and lacks universality

Engineering Contradiction:
Improvesignal securityVSAvoiduniversal applicability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces direct mechanical contact with conductive structures by using indirect capacitive coupling through a non-conductive substrate. The electrically conductive structure generates electric fields that interact with the capacitive sensor without requiring physical contact, thereby eliminating manipulation vulnerabilities while maintaining sensor detection capability.

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

Solution Approach 2:

The non-conductive substrate acts as an intermediary between the electrically conductive structure and the capacitive sensor. It allows the conductive structure to generate detectable signals while preventing direct contact that could enable manipulation, thus enhancing both security and universal applicability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If static electrically conductive structures are used, then the device is simple to manufacture, but the signals can be tampered with and are not time-dependent

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidsignal tamper resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces dynamic elements by requiring relative movement between the device and the capacitive sensor during operation. This movement generates time-dependent signal variations that are difficult to replicate or tamper with, while the static conductive structure itself remains simple to manufacture. The dynamic aspect is achieved through operational motion rather than complex structure.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If direct contact with conductive structures is required, then the interaction is strong and detectable, but the method is not intuitive and requires precise alignment

Engineering Contradiction:
Improvesignal detection accuracyVSAvoidoperational intuitiveness
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the need for precise mechanical alignment and direct contact with capacitive field interaction. The electrically conductive structure on the non-conductive substrate creates detectable electric fields at a distance, eliminating the need for precise alignment while maintaining strong signal detection through the capacitive coupling mechanism.

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

This approach provides a universally applicable, secure, and intuitive method for verification and identification, as the dynamic signals are uniquely generated, making manipulation difficult and enhancing protection against signal tampering.

Implementation Method 1

The electrically conductive structure of the device generates a quantity of essentially static signals on a capacitive area sensor, the static signals being deflected by an additional dynamic input with an input means and converted into dynamic signals

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP3853700B1Method, device and system for generating a time-dependent signal at a capacitive area sensor
Publication Date: 2023.04.12 PRISMADE LABS GMBH
  • EP3853700B1 patent drawingFigure 1a~1d
  • EP3853700B1 patent drawingFigure 2a~2d
  • EP3853700B1 patent drawingFigure 3

AI summary

The invention relates to a device comprising an electrically conductive structure on a non-conductive substrate for generating a time-dependent signal at a capacitive area sensor; a method for generating a tamper-proof time-dependent signal at a capacitive area sensor by means of a device of this type; and a system or kit for executing the method for generating a tamper-proof time-dependent signal at a capacitive area sensor.