Conductive Metal Pattern Darkening for Low-Visibility Transparent Substrates

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Solution Overview

Problem

Existing methods for creating electrically-conductive metal-containing patterns on transparent substrates fail to effectively reduce light reflectivity, making them visible and undesirable for applications like thin-film antennas.

Innovation Solution

A method involving a metallic pattern on a first substrate, where a first darkening agent is applied to one surface, transferred to a second substrate with that darkened surface in contact, and a second darkening agent is applied to the exposed surface of the metallic pattern on the second substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metallic pattern is applied to a transparent substrate to provide electrical conductivity, then electrical conductivity is improved, but optical transparency deteriorates due to light reflectivity

Engineering Contradiction:

Improveelectrical conductivityVSAvoidoptical transparency

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies different treatments to different surfaces of the metallic pattern. The front surface (visible side) receives a darkening treatment to reduce reflectivity, while the back surface maintains its conductive properties. This local differentiation allows the metallic pattern to provide electrical conductivity while minimizing visual detectability from the front surface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses darkening treatments (such as oxidation or coating with dark materials) to change the color/appearance of the metallic pattern's front surface. This color change reduces the surface's reflectivity and visual contrast against the transparent substrate, making the conductive pattern less observable while maintaining its electrical function.

Inventive Principle:

Principle #32Color changes

2Illumination intensity

If a darkening agent is applied to reduce light reflectivity of metallic patterns, then optical transparency is improved, but the metallic pattern becomes less electrically conductive

Engineering Contradiction:

Improveoptical transparencyVSAvoidelectrical conductivity

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The darkening agent is applied selectively to specific surfaces of the metallic pattern (typically the front visible surface) rather than uniformly to all surfaces. This localized application ensures that the darkening effect reduces reflectivity where visible, while leaving other surfaces untreated to maintain electrical conductivity pathways.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The darkening treatment is applied partially to the metallic pattern rather than completely covering all conductive elements. By applying the darkening agent only to the extent needed to reduce visual detectability (而非完全覆盖), the patent achieves sufficient optical transparency improvement while preserving adequate electrical conductivity for functional performance.

Inventive Principle:

Principle #16Partial or excessive action

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 significantly reduces the reflectivity of the metallic patterns, making them less observable, especially when viewed from either side of the substrate, thus enhancing their suitability for applications like vehicle windshields.

Implementation Method 1

A surface of the metallic pattern is darkened on the first substrate and the opposing surface of the metallic pattern is darkened after it is transferred to a second substrate, using appropriate darkening agents, to reduce metallic light reflectivity.

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS20250040056A1Method of providing article with electrically-conductive pattern

Publication Date: 2025.01.30 EASTMAN KODAK CO

AI summary

An article has an electrically-conductive metal-containing pattern and is prepared by: A) providing a metallic pattern on a first substrate; B) applying a darkening agent to the metallic pattern to form a first darkened surface; C) transferring the metallic pattern to a second substrate, leaving an undarkened second surface of the metallic pattern exposed to view; and D) applying a second darkening agent to the undarkened second surface. The first darkened surface formed in B) can have an L* value that is reduced by at least 1 unit compared to an L* value of the metallic pattern provided in A) before application of the darkening agent. Moreover, the second darkened surface formed in D) can have an L* value that is reduced by at least 1 unit compared to an L* value of the undarkened surface of the transferred metallic pattern provided in C).