Film-Based Capacitive Seat Sensor with Textile Spacer

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Solution Overview

Problem

Existing capacitive seat occupancy detection systems face challenges in mechanical robustness, humidity protection, and comfort integration due to the stiffness of all-film-based systems, which can lead to damage and corrosion when integrated into vehicle seats.

Innovation Solution

A capacitive detection system using film-based electrodes with a textile spacer layer, providing enhanced haptic properties and mechanical flexibility, and incorporating anti-electrolysis measures such as Ni-Cu electrodes or sealing layers, along with reinforcement pads to prevent damage and corrosion during fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If all-film-based electrodes are used, then manufacturing precision and electrical performance are improved, but mechanical robustness and resistance to damage deteriorate

Engineering Contradiction:

Improveelectrode configuration precisionVSAvoidmechanical robustness

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent combines film-based electrodes with textile substrate and spacer materials to create a composite structure. The film layer provides precise electrical properties and manufacturing consistency, while the textile composite provides mechanical strength, flexibility, and resistance to damage during installation and operation.

Inventive Principle:

Principle #40Composite materials

2Reliability

If all-film-based electrodes are used, then electrical performance is improved, but protection against humidity and water deteriorates

Engineering Contradiction:

Improveelectrical performanceVSAvoidhumidity and water protection

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The film-based electrode is combined with textile materials that can be treated for moisture resistance. The composite structure allows the film to maintain electrical performance while the textile layers provide environmental protection when properly coated or treated.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent employs sacrificial protective layers or coatings on the textile substrate that can degrade or be replaced, protecting the critical film-based electrode from humidity and water damage during normal operation.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If film-based electrodes are used, then manufacturing precision is improved, but ease of integration into seat compartment deteriorates

Engineering Contradiction:

Improveelectrode configurationVSAvoidintegration into seat

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By integrating the film-based electrode into a textile composite structure, the patent creates a flexible assembly that can be more easily conformally integrated into complex seat geometries while maintaining the precise electrode configuration provided by the film layer.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The film-based electrode structure is designed with inherent flexibility through thin-film construction and textile integration, allowing it to conform to the contours of the seat compartment during installation while maintaining manufacturing precision.

Inventive Principle:

Principle #30Flexible shells and thin films

4Measurement precision

If DC current is applied to electrodes, then occupancy detection capability is improved, but electrolysis and corrosion occur

Engineering Contradiction:

Improveoccupancy detectionVSAvoidelectrolysis and corrosion

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent employs sacrificial anode structures or protective coatings that can undergo electrolysis preferentially, protecting the main electrode structures from corrosion. These sacrificial elements are designed to be replaceable or self-regenerating.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The textile substrate and spacer materials act as intermediaries between the electrode and the humid environment, providing a barrier that reduces direct exposure to electrolytes while allowing the DC current to function for occupancy detection.

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

The system achieves improved mechanical robustness, reduced risk of damage, and enhanced seating comfort by using a combination of film-based electrodes and textile spacers, while preventing electrolysis and corrosion, thus effectively detecting seat occupancy.

Implementation Method 1

the detection of the capacitive coupling of a body to one or several electrodes arranged in the seat

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

the shielding electrode prevents the electric field from the sensing electrode to couple with the seat frame

Methodology Applied

Scientific EffectElectric field shielding: Electric Field

Data Source

PatentUS8049520B2System for capacitive detection of a seat occupancy

Publication Date: 2011.11.01 IEE INT ELECTRONICS & ENG SA

AI summary

A system for capacitive detection of seat occupancy in a vehicle comprises a sensing electrode and a shielding electrode arranged in substantially parallel layers. A spacer is arranged between the sensing electrode and the shielding electrode to keep the sensing electrode and the shielding electrode at a certain distance from each other. The spacer comprises an inner textile layer and at least one of the electrodes comprises a film-based electrode.