Patterned fiber substrate

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Solution Overview

Problem

Existing methods for forming fine wiring patterns on substrates are complicated, limit pattern design freedom, and result in substrates with low bending resistance, while multilayer circuit boards face challenges in applying conductive materials to via holes with small diameters and high aspect ratios.

Innovation Solution

A patterned fiber substrate is produced by forming a lyophilic region on the fiber substrate, applying a functional material solution or dispersion to this region, and removing the solvent, allowing the functional material to penetrate inside the substrate, resulting in a fine pattern with excellent bending resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a high-viscosity conductive ink is screen-printed to reduce bleeding, then the spreading of conductive ink is improved, but the wiring pattern can only be formed on the surface of the substrate resulting in low bending resistance

Engineering Contradiction:
Improvewiring pattern precisionVSAvoidbending resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent transitions from two-dimensional surface patterning to three-dimensional subsurface patterning by controlling conductive ink penetration depth. The conductive ink is made to penetrate into the fiber substrate to a controlled depth (e.g., 1-10 μm) rather than remaining only on the surface, thereby achieving both fine pattern precision and improved bending resistance through depth-based distribution.

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

Solution Approach 2:

The patent applies different concentrations or properties of conductive ink to different regions: the surface region maintains low conductivity to preserve pattern definition, while the subsurface region contains higher conductivity to ensure electrical function and bending resistance. This local differentiation resolves the contradiction between pattern precision and mechanical reliability.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If an underlayer is added to prevent spreading of conductive ink, then the pattern precision is improved, but the production method becomes complicated and thinness of the wiring structure is impaired

Engineering Contradiction:
Improvepattern precisionVSAvoidproduction method complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent removes the underlayer component entirely and replaces it with a controlled penetration mechanism. By adjusting ink viscosity, substrate porosity, and penetration depth parameters, the patent achieves pattern precision without requiring an additional underlayer structure, thereby simplifying the production method and maintaining substrate thinness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent controls pattern precision by changing parameters such as conductive ink viscosity, substrate porosity, and penetration depth rather than adding structural components. This parameter-based control approach eliminates the need for complex underlayer structures and reduces production complexity.

Inventive Principle:
Principle #35Parameter changes

3Strength

If conductive yarn is woven into the fiber substrate, then the wiring structure is formed, but the degree of freedom in pattern design is limited

Engineering Contradiction:
Improvewiring structure strengthVSAvoidpattern design freedom
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical weaving process with a direct penetration and deposition process. Conductive ink is applied and penetrates the fiber substrate to form wiring patterns, eliminating the constraints of yarn-based mechanical construction. This allows for complex, continuous, and free-form patterns that cannot be achieved through traditional weaving methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If conventional methods are used to apply conductive material to via holes with small diameters and high aspect ratios, then multilayer electrical connection is achieved, but the process becomes complicated and requires advanced techniques

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses the fiber substrate itself as an intermediary medium that facilitates conductive material penetration. The controlled porosity and structure of the fiber substrate act as a natural guide and support for the conductive ink, enabling it to penetrate vertically through multiple layers without requiring complex via hole formation processes or advanced application techniques.

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

The method enables the production of a patterned fiber substrate with a fine pattern and improved bending resistance using a wide range of functional materials, and facilitates the creation of multilayer circuit boards without the need for via holes.

Implementation Method 1

the fiber substrate has a contact angle of 100 to 170° with pure water on its surface

Methodology Applied
Scientific EffectHydrophobicity: Hydrophobe

Implementation Method 2

at least a part of the functional material that constitutes the pattern is present in inside of the fiber substrate

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP3904580B1Patterned fiber substrate
Publication Date: 2025.11.12 KURARAY CO LTD
  • EP3904580B1 patent drawingFigure 1~2
  • EP3904580B1 patent drawingFigure 3~5
  • EP3904580B1 patent drawingFigure 6~7

AI summary

The present invention relates to a patterned fiber substrate comprising: a fiber substrate; and a pattern consisting of a functional material and formed on the fiber substrate, wherein at least a part of the functional material that constitutes the pattern is present in inside of the fiber substrate, the fiber substrate has a contact angle of 100 to 170° with pure water on its surface, and the pattern has a narrowest line width of 1 to 3000 µm.