Graphene Touch Sensor for Simultaneous Pressure and Position Detection

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Solution Overview

Problem

Conventional touch screens face challenges in achieving high accuracy, input speed, and large screen size implementation while maintaining a simplified structure and improved performance, particularly in integrating multi-media functions within restricted electronic device sizes.

Innovation Solution

A touch sensor utilizing graphene electrodes and strain gauges to simultaneously detect pressure and position through resistance changes, enabling multi-touch functionality, improved uniformity, and reproducibility, with the ability to form flexible and stretchable sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional resistive or capacitive touch screen structures are used, then touch detection function is achieved, but device complexity increases and manufacturing precision requirements are high

Engineering Contradiction:
Improvetouch sensor structureVSAvoidalignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent combines multiple functions into a single graphene layer: the graphene serves simultaneously as the transparent electrode and the strain gauge material. This merging eliminates the need for separate ITO electrode layers and strain gauge patterns, significantly reducing device complexity and the number of manufacturing steps while lowering alignment precision requirements between multiple layers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The graphene layer performs multiple functions: it acts as the transparent conductive electrode, the strain sensing element, and the structural component. This multi-functionality reduces the overall number of components needed in the touch sensor, simplifying the device structure and reducing manufacturing complexity compared to conventional multi-layer designs.

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

2Device complexity

If graphene is used as both electrode and strain gauge, then device structure is simplified, but manufacturing precision requirements increase for graphene patterning

Engineering Contradiction:
Improvelayer structureVSAvoidgraphene pattern alignment
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent merges the electrode function and strain gauge function into a single graphene layer, eliminating the need for separate ITO electrode layers and strain gauge patterns. This reduces the total number of patterning steps and alignment requirements between different material layers, even though precise graphene patterning is needed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes the unique property of graphene where its electrical resistance changes in response to mechanical strain. By patterning the graphene layer itself to serve dual purposes, the system changes the functional parameters of a single material rather than requiring precise alignment of multiple specialized layers, reducing overall manufacturing precision requirements.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If conventional touch sensors are used, then basic touch detection is achieved, but simultaneous pressure and position detection with high precision is difficult

Engineering Contradiction:
Improvetouch position and pressure detection precisionVSAvoidsensor configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines position detection and pressure detection capabilities into a single graphene-based sensing layer. The resistive type detects position through voltage division at touch points, while the strain gauge effect simultaneously measures pressure magnitude through resistance changes. This merging allows simultaneous detection of both parameters with high precision without requiring separate sensor systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The graphene layer provides multi-functional sensing: it detects touch position through its resistive properties and simultaneously detects pressure magnitude through its piezoresistive/strain gauge properties. This universal sensing capability within a single layer achieves high measurement precision for both position and pressure while avoiding the complexity of multiple separate sensing systems.

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

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 solution allows for precise detection of touch positions and pressures, enhances user convenience by enabling larger display screens, and provides a flexible, transparent, and stretchable touch sensor suitable for various applications, including 3D sensing.

Implementation Method 1

a touch sensor capable of simultaneously measuring a pressure and a position by using graphene by means of change in resistance

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 2

using graphene electrodes and strain gauges to simultaneously detect pressure and position through resistance changes

Methodology Applied
Scientific EffectStrain gauge effect: Deformation

Data Source

PatentEP3686719B1Touch sensor using graphene for simultaneously detecting a pressure and a position
Publication Date: 2024.08.14 GRAPHENE SQUARE INC
  • EP3686719B1 patent drawingFigure 1
  • EP3686719B1 patent drawingFigure 2
  • EP3686719B1 patent drawingFigure 3

AI summary

Provided is a touch sensor for measuring a touch position and/or the degree of touching pressure by using graphene as an electrode and/or a strain gauge, and more particularly, to a touch sensor for simultaneously detecting pressure and position by means of change in resistance by using the graphene.