Anisotropic Touch Panel Using Carbon Nanotube Films

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Solution Overview

Problem

Conventional capacitive-type touch panels face challenges in improving yield ratio, reducing production cost and time, and enhancing touch control precision due to complex manufacturing processes and limitations in process resolution.

Innovation Solution

A touch panel design featuring anisotropic conductive films, specifically carbon nanotube films, with pads disposed along specific axes, coupled with driving and sensing circuits to input and read electronic signals, allowing precise determination of touch points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional transparent conductive materials (ITO) and semiconductor manufacturing technologies are used, then the touch panel can be manufactured with existing processes, but the yield ratio cannot be improved, production cost and time cannot be decreased, and touch control precision cannot be further upgraded

Engineering Contradiction:

Improvetouch control precisionVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the electrical parameter characteristics by using anisotropic conductive films instead of conventional isotropic ITO materials. The anisotropic films have different conductivity in different directions, which enables more precise touch control while simplifying the manufacturing process. This parameter change resolves the contradiction by improving touch control precision without increasing manufacturing complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures with multiple conductive layers having different anisotropic characteristics. By combining materials with complementary properties, the system achieves enhanced touch precision while maintaining manufacturing simplicity. The composite approach allows optimization of both precision and process complexity simultaneously.

Inventive Principle:

Principle #40Composite materials

2Productivity

If conventional capacitive-type touch panel structures are used, then the basic touch detection function is achieved, but the production yield ratio is limited and production cost and time cannot be reduced

Engineering Contradiction:

Improveproduction yield ratioVSAvoidtouch detection accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent divides the conductive structure into multiple segmented layers with different orientations. The first conductive layer has anisotropic conductivity in one direction while the second layer provides anisotropic conductivity in a perpendicular direction. This segmentation enables independent optimization of each layer for manufacturing efficiency while collectively achieving high touch detection accuracy, thus resolving the contradiction between productivity and reliability.

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If process resolution limitations are accepted, then conventional manufacturing can be maintained, but touch control precision cannot be further upgraded

Engineering Contradiction:

Improvetouch control precisionVSAvoidprocess resolution

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent replaces the reliance on mechanical/optical process resolution with electrical field-based detection. By using anisotropic conductive films that create directional electrical fields, the system achieves high touch precision through electrical measurement rather than depending on physical process resolution limits. This substitution resolves the contradiction by decoupling manufacturing precision from process resolution constraints.

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

The design enhances touch control precision and potentially reduces production costs by simplifying the manufacturing process and improving the accuracy of touch point location on the touch panel surface.

Implementation Method 1

Each of the first conductive film and the second conductive film has anisotropic impedance

Methodology Applied

Scientific EffectAnisotropic impedance: Anisotropy

Implementation Method 2

The impedance of the first conductive film along the second direction is less than the impedance along other directions

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

Each of the first conductive film and the second conductive film has anisotropic impedance, such as carbon nanotube (CNT) films

Methodology Applied

Scientific EffectCarbon nanotube conduction: Carbon Nanotubes

Data Source

PatentUS8681118B2Touch panel and a method of locating a touch point of the same

Publication Date: 2014.03.25 INNOLUX CORP

AI summary

The present disclosure is directed to a touch panel and a method of locating a touch point. An insulating layer is disposed between a first insulating substrate and a second insulating substrate. A first conductive film with anisotropic impedance is disposed between the first insulating substrate and the insulating layer, and a second conductive film with anisotropic impedance is disposed between the insulating layer and the second insulating substrate. Multiple first pads are disposed on a peripheral region of the first conductive film along a first direction, and multiple second pads are disposed on a peripheral region of the second conductive film along a second direction. The first conductive film has least impedance along the second direction, and the second conductive film has least impedance along the first direction.