Flexible Touch Panel with Bend and Touch Sensing

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Solution Overview

Problem

Bendable and foldable displays face challenges in automatically detecting configurations and distinguishing between touch panel input actions and bending/folding actions, requiring a solution that enables seamless switching between flat and folded states while preventing interference between touch and bending sensing.

Innovation Solution

A flexible touch panel apparatus with a plurality of electrodes, an elastomeric layer, and an insulator layer, where the second electrodes are capacitively coupled for bend sensing and the third electrodes for touch sensing, allowing for force sensing and differentiation between touch and bending actions through capacitance changes and shielding mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single touch panel structure is used for both touch sensing and bend sensing, then device complexity is reduced, but measurement precision deteriorates due to interference between touch and bending detection

Engineering Contradiction:

Improvetouch panel structureVSAvoiddetection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The touch panel is segmented into distinct functional regions with separate electrode systems: first electrodes and second electrodes for bend sensing, and third electrodes for touch sensing. This segmentation allows independent operation of touch and bend detection functions, eliminating interference between the two sensing modes while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If the elastomeric layer is made flexible to enable folding, then adaptability improves, but structural stability deteriorates during sensing operations

Engineering Contradiction:

Improvefolding capabilityVSAvoidlayer structure stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The touch panel employs a composite structure combining multiple materials with different properties: a flexible elastomeric layer for bending capability, rigid insulator layers for structural stability, and conductive electrode materials for sensing. This composite approach allows the elastomeric layer to provide folding adaptability while the insulator layers maintain structural integrity and electrical isolation during sensing operations.

Inventive Principle:

Principle #40Composite materials

3Measurement precision

If the second electrode is positioned close to the first electrode for sensitive bend detection, then measurement precision improves, but touch sensing interference increases

Engineering Contradiction:

Improvebend detection sensitivityVSAvoidcapacitive interference

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

An insulator layer is introduced as an intermediary between the first electrodes and second electrodes. This insulator layer provides electrical isolation that prevents capacitive interference from affecting bend detection accuracy, while still allowing the electrodes to be positioned close enough for sensitive bend detection through the insulating medium.

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

Enables accurate detection of bending and touch actions, allowing the display to automatically adjust its layout and functionality between flat and folded configurations, enhancing user interaction and device usability.

Implementation Method 1

the second electrode is capacitively coupled to at least one of the plurality of first electrodes for bend sensing in the flexible touch panel along the bending axis

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

the elastomeric layer preferably has a modulus of elasticity below 1 MPa

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

the plurality of third electrodes are capacitively coupled to the plurality of first electrodes for touch sensing on the flexible touch panel

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 4

An insulator layer is disposed between the at least one second electrode and the plurality of third electrodes

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS11527584B2Touch panel integrating bending sensor for foldable OLED display

Publication Date: 2022.12.13 SHARP KK

AI summary

A flexible touch panel apparatus includes a series of first electrodes extending along a first direction, at least one second electrode extending along a second direction and defining a bending axis of the flexible touch panel. An elastomeric layer is located between the series of first electrodes at least second electrode. A series of third electrodes are extending along the second direction parallel to the bending axis, and an insulator layer is located between at least one second electrode and the series of third electrodes. At least one second electrode is capacitively coupled to at least one of the series of first electrodes for bend sensing in the flexible touch panel along the bending axis, and the third electrodes are capacitively coupled to the first electrodes for touch sensing on the flexible touch panel.