Capacitive Sensor System for Multimodal Force and Proximity Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional sensors, particularly those based on semiconductors and rigid materials, are inflexible and unsuitable for precise, location-selective, and multimodal measurements, especially on two-dimensionally movable or curved surfaces like textiles or human skin, due to material properties and geometric limitations.

Innovation Solution

A capacitive sensor system comprising a dielectric body made of elastomers with elastic electrodes and a multiplexer for dynamic signal assignment, allowing for flexible and stretchable multimodal measurements by distinguishing between measuring, reference, and neutral electrodes, and enabling spatial resolution and modality selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional rigid sensors are used, then measurement precision is improved, but adaptability to flexible surfaces deteriorates

Engineering Contradiction:
Improvemeasurement precisionVSAvoidadaptability to flexible surfaces
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent employs thin film-based capacitive sensors with flexible substrate materials that can conform to curved and flexible surfaces while maintaining measurement capability. The sensor structure includes flexible electrode layers and dielectric layers that bend without compromising electrical performance, enabling precise measurements on non-planar surfaces.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent utilizes composite material structures combining flexible substrates with conductive and dielectric layers to create sensors that maintain mechanical flexibility while preserving electrical measurement functions. The multi-layer composite design allows the sensor to adapt to surface geometry while providing accurate capacitance measurements.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If multiple sensor types are distributed on a surface for spatially resolved measurements, then measurement capability is improved, but device complexity increases

Engineering Contradiction:
Improvemultimodal measurement capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal capacitive sensor platform that can perform multiple measurement functions (proximity, contactless force, contact force, deformation) using the same basic sensor structure and readout electronics. By varying the electrode configuration and measurement mode rather than using different sensor types, the system achieves multimodality while minimizing complexity.

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

Solution Approach 2:

The patent combines multiple measurement functions into a single integrated capacitive sensor system. Different measurement modes (proximity, force, deformation) are achieved by processing capacitance measurements from the same electrode structure in different ways, merging what would traditionally require separate sensors into one unified device.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If inelastic electrode materials are used for proximity detection, then measurement stability is improved, but sensor flexibility deteriorates

Engineering Contradiction:
Improveelectrode stabilityVSAvoidsensor flexibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent uses flexible thin film electrodes that can bend and deform with the sensor substrate while maintaining electrical conductivity and measurement stability. The thin film structure provides mechanical flexibility without sacrificing electrical performance, allowing the electrode to adapt to surface geometry changes.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs composite electrode structures combining flexible conductive materials with supportive matrix materials. This composite approach maintains electrical stability and conductivity while providing the mechanical flexibility needed for conformable sensor applications on curved or deformable surfaces.

Inventive Principle:
Principle #40Composite materials

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 precise localization and differentiation of multiple external influences with reduced complexity, enabling flexible installation and cost-effective production, and dynamic switching between measurement modes such as proximity and pressure detection.

Implementation Method 1

Dielectric elastomer sensors are flexible and stretchable sensors with a capacitive measuring principle

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

In their simplest form, they consist of a stretchable elastomer film as the dielectric, coated on both sides with conductive and also stretchable layers as electrodes

Methodology Applied
Scientific EffectDielectric: Dielectric

Implementation Method 3

They consist of a dielectric body made of elastomers... The at least one dielectric body and the electrodes are elastically deformable by more than 5%

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3736541B1Capacitive sensor system and method for multimodal and / or location-selective measurement of forces, deformations and / or object proximity
Publication Date: 2024.02.28 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3736541B1 patent drawingFigure 1~3
  • EP3736541B1 patent drawingFigure 4~6
  • EP3736541B1 patent drawingFigure 7a~7b

AI summary

The present invention relates to a capacitive sensor system for the multimodal and/or location-selective measurement of forces, deformations, and/or object proximity, as well as a corresponding measurement method. The capacitive sensor system according to the invention is used in the industrial, automotive, medical, and sports and leisure sectors.