Patterned Wavelength-Selective Film via Barrier-Assisted Break

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Solution Overview

Problem

Existing wavelength-selective films are difficult to apply in unique patterns on substrates, particularly retroreflective films, which limits their visibility and detectability in both daytime and nighttime conditions.

Innovation Solution

A method involving a structurally weak wavelength-selective film with selectively located barriers on adhesive regions, allowing the film to break and remain patterned on the substrate, while the barrier separates and remains with the adhesive, enabling cost-effective patterned application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a wavelength-selective film is applied to a substrate, then high-contrast patterns are achieved, but the film is difficult to apply in unique patterns particularly on retroreflective films

Engineering Contradiction:
Improvepattern application precisionVSAvoidease of patterned application
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies a barrier layer to the substrate before applying the wavelength-selective film. This preliminary action creates defined adhesive regions where the film will bond, enabling precise pattern formation without requiring complex post-application processing. The barrier layer is applied in advance to control where the film adheres, solving the contradiction between achieving precise patterns and maintaining ease of manufacture.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The barrier layer serves as an intermediary between the substrate and the wavelength-selective film. It mediates the adhesion process by providing specific regions that promote or prevent bonding, allowing the film to be applied in unique patterns while maintaining ease of manufacture. This intermediary layer enables precise pattern control without complicating the overall manufacturing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If a structurally weak wavelength-selective film is used, then the film breaks to remain in contact with adhesive regions forming patterns, but the film structure becomes more fragile

Engineering Contradiction:
Improvepattern formation precisionVSAvoidfilm structural strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent converts the harmful effect of film fragility into a beneficial pattern formation mechanism. By designing the film to be structurally weak, it intentionally breaks at controlled locations during application, with the broken portions remaining in contact with adhesive regions to form precise patterns. This transforms the weakness from a defect into a feature that enables accurate pattern formation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the structural parameter of the wavelength-selective film by making it intentionally weak. This parameter change allows the film to break during application, and the broken portions remain adhered to the substrate in the desired pattern. The structural weakness is controlled to ensure proper pattern formation while maintaining sufficient integrity for handling during the application process.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If barriers are selectively located on adhesive regions, then unique patterned embedded images are achieved, but the process complexity increases

Engineering Contradiction:
Improveunique pattern capabilityVSAvoidprocess complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The barrier layer serves multiple functions: it defines adhesive regions, controls pattern formation, and enables unique patterned embedded images. This multi-functionality allows the same simple barrier application process to achieve versatile pattern designs without increasing process complexity. The barrier layer's universal role in the process enables adaptability for different patterns while maintaining process simplicity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 allows for high-contrast patterned wavelength-selective films to be applied to substrates, ensuring visibility in both daytime and nighttime conditions, enhancing detectability and usability in light directing articles.

Implementation Method 1

Wavelength-selective films typically reflect off axis, absorb, or scatter the selected wavelength

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

Wavelength-selective films typically reflect off axis, absorb, or scatter the selected wavelength

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

Wavelength-selective films typically reflect off axis, absorb, or scatter the selected wavelength

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 4

Retroreflective elements reflect incident light back towards the direction of the light source

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Implementation Method 5

The adhesion between the wavelength-selective film and the adhesive is greater than the force keeping the wavelength-selective film intact

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3826832B1A patterned wavelength-selective film
Publication Date: 2023.09.06 3M INNOVATIVE PROPERTIES CO
  • EP3826832B1 patent drawingFigure 1A~2A
  • EP3826832B1 patent drawingFigure 2B~4
  • EP3826832B1 patent drawingFigure 5~7

AI summary

The disclosed patterned wavelength-selective material and process for making the patterned wavelength-selective material uses selectively located barriers to the adhesive regions. A structurally weak wavelength-selective material includes portions that contact the adhesive regions and break to remain in contact with the adhesive. The wavelength-selective material does not contact the adhesive regions covered by the barrier and is removed leaving a wavelength-selective film in a pattern at the adhesive regions.