Fluorescence Display Interlayers With PVA Migration Barriers

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Solution Overview

Problem

Current laminated glass interlayers using PVB and PET for automotive displays suffer from high haze levels due to migration of fluorescent molecules, affecting transparency and image quality.

Innovation Solution

A multilayer thermoplastic interlayer comprising polyvinyl acetal films with functional additives and polyvinyl alcohol barrier films to prevent migration, ensuring improved transparency and image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PET barrier films are used to prevent fluorescent molecule migration, then migration is reduced, but haze level increases and transparency decreases

Engineering Contradiction:
Improveprevention of fluorescent molecule migrationVSAvoidtransparency of visible light
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the material parameter from PET to polyvinyl alcohol (PVA) for the barrier films. This parameter change maintains the barrier function against fluorescent molecule migration while improving optical transparency and reducing haze level, as PVA is optically clearer than PET in the visible spectrum.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite interlayer structure combining polyvinyl acetal functional films with polyvinyl alcohol barrier films. This composite approach allows the functional additives to be contained effectively while maintaining overall optical clarity, as the PVA barrier layers are optically superior to traditional PET barriers.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple barrier films are added to prevent migration, then fluorescent molecule containment improves, but device complexity increases

Engineering Contradiction:
Improvecontainment of fluorescent moleculesVSAvoidnumber of films in interlayer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the interlayer structure into distinct functional films (polyvinyl acetal with fluorescent additives) and barrier films (polyvinyl alcohol). This segmentation allows each layer to perform its specific function optimally while maintaining a relatively simple overall structure compared to using multiple different material types.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The polyvinyl alcohol barrier films act as intermediary layers between the polyvinyl acetal functional films. These intermediary PVA layers provide effective migration blocking with minimal optical impact, serving as a mediating solution that balances containment requirements with transparency needs.

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 solution significantly reduces haze levels, maintaining transparency and enhancing image quality in automotive glazing displays.

Implementation Method 1

the barrier films C generally have the purpose that the functional additives present in the films A1, A2 and A3 do not migrate from one film to the other

Methodology Applied
Scientific EffectMigration prevention:

Implementation Method 2

the fluorescent compound has a size of less than 500 nm, more preferably between 1 pm and 100 nm, most preferably between 10 and 1000 pm

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

emissive projection displays (EPD) have been developed that use the principles of fluorescent conversion of luminescent materials

Methodology Applied
Scientific EffectFluorescent conversion: Photoluminescence

Data Source

PatentEP4444541B1Fluorescence display
Publication Date: 2025.10.29 KURARAY EURO GMBH

AI summary

The present invention relates to functionalized laminates, specifically to windshields or architectural glazing with display systems projected thereon.