Capacitive Deformation Sensing for Flexible Electronics

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Solution Overview

Problem

Existing deformation detection methods for flexible electronic devices, such as mobile phones and tablets, face challenges with cyclic durability and reliable attachment of sensors, particularly in miniaturized and mass-manufactured driving circuitry, and are not suited for mobile devices.

Innovation Solution

The solution involves using capacitive measurement to detect changes in space within the device by measuring relative movement or changes in gaps between parts, allowing for contactless deformation sensing, which utilizes the existing touch screen capacitive environment and eliminates the need for sensors to experience deformation strains.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strain-sensitive sensors are attached to flexible device surfaces to detect deformation, then deformation detection capability is improved, but cyclic durability and reliable attachment deteriorate due to sensor failure under repeated bending and twisting

Engineering Contradiction:
Improvedeformation detection capabilityVSAvoidcyclic durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces mechanical strain-sensitive sensors with a capacitive measurement system that uses electrical fields to detect deformation. The capacitive sensor arrangement measures changes in capacitance caused by deformation-induced changes in the electric field between conductive elements, eliminating the need for mechanical sensors that fail under cyclic bending and twisting.

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

Solution Approach 2:

The patent introduces an intermediary measurement approach by using the capacitive coupling between conductive elements as a mediator to detect deformation. Instead of directly measuring strain on the sensor, the system measures the intermediary effect of deformation on the electric field and capacitance, which provides indirect but reliable deformation detection without subjecting sensors to mechanical stress.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If specialized deformation sensors are integrated into flexible devices, then measurement capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvedeformation sensing capabilityVSAvoidcomponent count
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the capacitive sensor arrangement serve multiple functions: it can detect touch input, detect device deformation, and potentially serve as part of the display structure. This multi-functionality eliminates the need for separate deformation sensors, reducing component count and manufacturing complexity while maintaining deformation detection capability.

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

Solution Approach 2:

The patent merges the deformation sensing function with the existing capacitive touch sensor infrastructure. By combining touch sensing and deformation detection into a single capacitive measurement system, the patent reduces the number of components needed and simplifies the overall device architecture.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If sensors are attached to experience deformation directly for accurate measurement, then measurement accuracy is improved, but sensor reliability deteriorates due to exposure to deformation strains

Engineering Contradiction:
Improvedeformation measurement accuracyVSAvoidsensor durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces mechanical sensors that must physically experience deformation with an electrical field-based capacitive measurement system. The capacitive sensors measure deformation indirectly through changes in capacitance caused by the deformation of the structure surrounding the sensors, allowing accurate measurement without direct mechanical stress on the sensing elements.

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 durable and cost-effective deformation detection method that reduces the need for strain-sensitive sensors and minimizes component count, leveraging existing capacitive sensing technology in mobile devices.

Implementation Method 1

The apparatus comprises capacitive measurement means configured to detect changes in space within the apparatus

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2874048B1Flexible device deformation measurement
Publication Date: 2019.07.31 NOKIA TECHNOLOGIES OY
  • EP2874048B1 patent drawingFigure 1a~2
  • EP2874048B1 patent drawingFigure 3a~3b
  • EP2874048B1 patent drawingFigure 4a~4b

AI summary

Monitoring deformation of a flexible electronic apparatus. Changes in space within the apparatus between at least two measurement points are detected; and degree of deformation of the apparatus is determined based on the detected changes in the space within the apparatus between the at least two measurement points.