Flexible Touch Panel Piezoelectric Bending State Detection

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Solution Overview

Problem

Existing flexible touch panels lack effective mechanisms to sense bending and adapt operation modes based on the bending state, limiting their functionality and user experience.

Innovation Solution

A flexible touch panel with a layer of piezoelectric material between first and second electrodes, connected to a device that tracks changes in bending state by analyzing piezoelectric signals, allowing for determination of radii of curvature and user interactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible touch panels are made without bending sensing capability, then manufacturing is simpler and device complexity is reduced, but adaptability and user interaction capabilities are limited

Engineering Contradiction:
Improvebending state adaptabilityVSAvoidsensing mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines capacitive touch sensing electrodes with piezoelectric force sensing layers into a single integrated sensor stack. The same electrode structure serves both capacitive touch detection and piezoelectric force detection functions, eliminating the need for separate sensing mechanisms and reducing overall device complexity while enabling bending state adaptability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor stack is designed to perform multiple functions simultaneously: capacitive touch detection, piezoelectric force detection, and bending state sensing. This multi-functional approach allows the flexible touch panel to adapt to different operating modes (folded, unfolded, rolled) without requiring additional dedicated sensors for each function.

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

2Measurement precision

If flexible touch panels incorporate piezoelectric layers for force detection, then force sensing capability is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveforce detection precisionVSAvoidsensor architecture complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent integrates the piezoelectric force sensing layer within the existing capacitive touch sensor stack, rather than adding it as a separate external component. This merging approach maintains force detection precision while reducing the overall complexity of the sensor architecture by sharing common structural elements and processing circuits.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If flexible touch panels add bending sensing capability, then operating mode adaptability is improved, but energy consumption increases

Engineering Contradiction:
Improveoperating mode adaptabilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent uses piezoelectric material to convert mechanical bending stress directly into electrical signals for bending state detection. This eliminates the need for complex mechanical switches, Hall effect sensors, or other active sensing components that would consume additional power, thereby enabling operating mode adaptability with minimal energy overhead.

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 the flexible touch panel to detect bending states and switch between operating modes, enhancing user interaction capabilities and power management, while maintaining flexibility and durability.

Implementation Method 1

a layer of piezoelectric material arranged between a number of first electrodes and at least one second electrode

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3999943B1Flexible touch panel with piezoelectric force sensing
Publication Date: 2025.05.14 CAMBRIDGE TOUCH TECH
  • EP3999943B1 patent drawingFigure 1
  • EP3999943B1 patent drawingFigure 2~4
  • EP3999943B1 patent drawingFigure 5

AI summary

An apparatus is described which includes a flexible touch panel (21). The flexible touch panel (21) includes a layer of piezoelectric material (9) arranged between a number of first electrodes (7, 8) and at least one second electrode (8, 14). The apparatus also includes a device (3) connected to the first electrodes (7, 8) and configured to determine one or more radii of curvature (R 1 , R 2 ) of the flexible touch panel (21) based on signals received from one or more of the first electrodes (7, 8).