Carbon Nanotube Touch Panel for Durability and Transparency

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Solution Overview

Problem

Conventional capacitance-type touch panels with indium tin oxide (ITO) layers suffer from poor mechanical durability, low chemical endurance, uneven resistance, and low transparency, leading to reduced sensitivity, accuracy, and brightness.

Innovation Solution

A touch panel with a transparent conductive layer composed of stacked carbon nanotube layers, where each layer has carbon nanotubes aligned in the same direction, and adjacent layers have carbon nanotubes aligned at an angle between 0° to 90°, providing improved mechanical strength, uniform conductivity, and high transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If indium tin oxide (ITO) is used as the transparent conductive layer, then the touch panel can be manufactured with conventional processes, but the mechanical durability and chemical endurance are poor

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidmechanical durability and chemical endurance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the conventional ITO material with carbon nanotubes arranged in stacked layers. Carbon nanotubes possess superior mechanical strength and chemical stability compared to ITO, while maintaining optical transparency and electrical conductivity. This material substitution resolves the contradiction by achieving both ease of manufacture through simple deposition processes and enhanced reliability through the inherent properties of carbon nanotubes.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If indium tin oxide (ITO) is used as the transparent conductive layer, then the touch panel can be fabricated using standard techniques, but the resistance is uneven and transparency is low

Engineering Contradiction:

Improvefabrication simplicityVSAvoidresistance uniformity and transparency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent divides the transparent conductive layer into multiple stacked carbon nanotube layers, with each layer containing nanotubes oriented in a specific direction. This segmentation approach allows for better control over electrical resistance distribution and optical properties. The multi-layer structure with oriented nanotubes achieves uniform resistance and high transparency while maintaining fabrication simplicity through sequential deposition processes.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If conventional ITO-based processes are used, then the touch panel can be produced with existing equipment, but sensitivity and accuracy are reduced

Engineering Contradiction:

Improvecompatibility with existing equipmentVSAvoidtouch sensitivity and accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent changes the material parameter from ITO to carbon nanotubes, which fundamentally alters the electrical and optical characteristics. Carbon nanotubes provide superior electrical conductivity and optical transparency, leading to enhanced touch sensitivity and accuracy. The fabrication process remains compatible with existing equipment through simple deposition techniques, thus resolving the contradiction between adaptability and measurement precision.

Inventive Principle:

Principle #35Parameter changes

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 carbon nanotube-based touch panel offers enhanced durability, sensitivity, accuracy, and brightness, with a simple and cost-effective fabrication method that replaces the need for vacuum environments and heat processing, suitable for mass production.

Implementation Method 1

The transparent conductive layer includes at least two stacked carbon nanotube layers, and each carbon nanotube layer includes a plurality of carbon nanotubes arranged along a same direction

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

each carbon nanotube layer includes a plurality of carbon nanotubes arranged along a same direction. Carbon nanotubes of adjacent carbon nanotube layers are arranged along different directions

Methodology Applied

Scientific EffectCarbon nanotube structure: Carbon Nanotubes

Implementation Method 3

each carbon nanotube layer includes a plurality of carbon nanotubes arranged along a same direction. Carbon nanotubes of adjacent carbon nanotube layers are arranged along different directions

Methodology Applied

Scientific EffectOriented structure strengthening:

Implementation Method 4

providing improved mechanical strength, uniform conductivity, and high transparency

Methodology Applied

Scientific EffectOptical transparency:

Data Source

PatentUS8237671B2Touch panel and display device using the same

Publication Date: 2012.08.07 TSINGHUA UNIVERSITY

AI summary

A touch panel includes a substrate, a transparent conductive layer, and at least two electrodes. The transparent conductive layer is formed on a surface of the substrate. The transparent conductive layer includes at least two carbon nanotube layers, and each carbon nanotube layer includes a plurality of carbon nanotubes arranged along a same direction. The carbon nanotubes of adjacent carbon nanotube layers are arranged along different directions. The electrodes are electrically connected with the transparent conductive layer. Further, a display device using the touch panel is also included.