Touch Panel Conductive Pattern Aperture Ratio Lamination

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Solution Overview

Problem

Existing touch panels face challenges in maximizing transmittance, concealing properties, and uniformity due to high resistance of transparent conductive films, especially when scaling up and maintaining visibility, which is exacerbated by the need for precise alignment and lamination of metal lines.

Innovation Solution

The solution involves creating conductive patterns with different aperture ratios on both surfaces of a transparent substrate, allowing for lamination to enhance transmittance and uniformity by ensuring uniform and high transmittance, while minimizing the impact of line breakage and maintaining electric circuit constitution through pattern design on separate layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a transparent conductive film is used to maintain visibility and concealing properties, then transmittance is improved, but resistance increases to 100 ohms/square or more, lowering sensitivity

Engineering Contradiction:
ImprovetransmittanceVSAvoidsensitivity
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent combines a transparent conductive film layer with a metal pattern layer to create a hybrid conductive structure. The transparent conductive film provides baseline conductivity and optical transparency, while the metal pattern overlay provides additional conductive pathways that reduce overall resistance without significantly impacting transmittance, thus resolving the contradiction between maintaining visibility and reducing resistance for sensitivity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses a composite structure consisting of transparent conductive film material combined with metal pattern material. This composite approach allows the system to benefit from both materials: the transparent conductive film provides optical clarity and baseline electrical properties, while the metal pattern contributes low resistance pathways, achieving both high transmittance and low resistance simultaneously.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the size of screen is increased to meet large scale manufacturing demands, then productivity is improved, but cost of the ITO film is rapidly increased

Engineering Contradiction:
Improvemanufacturing scaleVSAvoidcost
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent employs metal patterns that can be more cost-effective than ITO film for large area applications. The metal pattern structure allows for alternative material choices that reduce material costs when scaling up production, making large screen manufacturing more economically viable while maintaining required electrical performance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The conductive function is segmented between the transparent conductive film and the metal pattern layers. This segmentation allows each layer to be optimized independently - the transparent conductive film can be applied in standard manufacturing processes while the metal pattern is added selectively to provide additional conductivity, enabling cost-effective scaling without requiring expensive ITO film across the entire large area.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If a dummy pattern is introduced to implement uniform transmittance on one surface, then uniformity is improved, but loss of transmittance occurs due to the presence of an additional region not providing a large electric affection

Engineering Contradiction:
ImproveuniformityVSAvoidtransmittance
Core Design Contradiction:
Stability of the object's compositionVSIllumination intensity

Solution Approach 1:

The patent addresses transmittance uniformity by moving from a single-layer approach to a multi-layer structure with the metal pattern overlay. This dimensional change allows the metal pattern to be positioned and designed to compensate for non-uniformities in the transparent conductive film, achieving uniform optical appearance without requiring additional dummy patterns that would reduce overall transmittance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The metal pattern is strategically designed with varying local densities and configurations to compensate for regional variations in the transparent conductive film's properties. By adjusting the local quality of the metal pattern overlay, the system achieves uniform overall transmittance without adding dummy patterns that would reduce total light transmission.

Inventive Principle:
Principle #3Local quality

4Manufacturing precision

If precise alignment and lamination of metal line are ensured to maintain visibility, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent incorporates alignment marks and registration features directly into the metal pattern design and manufacturing process. These preliminary alignment elements are built in during fabrication, enabling precise registration between the transparent conductive film and metal pattern layers without requiring complex external alignment equipment or procedures, thus maintaining manufacturing precision while limiting complexity growth.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2763003B1Touch panel comprising conductive pattern
Publication Date: 2019.08.14 LG CHEM LTD
  • EP2763003B1 patent drawingFigure 1
  • EP2763003B1 patent drawingFigure 2
  • EP2763003B1 patent drawingFigure 3

AI summary

The present invention relates to a touch panel comprising a conductive pattern having improved transmittance and concealing property, and the touch panel according to the present invention can have an effect of improvement in transmittance, a concealing property, and uniformity, and a reduction in strength of a diffraction pattern by reflection light in a conductive pattern by providing the conductive patterns comprising regions having different aperture ratios on both surfaces of a transparent substrate at predetermined positions, or laminating the transparent substrate having the conductive patterns comprising the regions having different aperture ratios.