Direct-Laminated Polarizing Laminate Moisture-Heat Resistance

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Solution Overview

Problem

Laminates composed of a light absorption anisotropic layer and an optically anisotropic layer, when exposed to high-temperature and high-humidity environments, suffer from reticulation and degraded moisture-heat resistance due to the use of a pressure sensitive adhesive layer in existing technologies.

Innovation Solution

A laminate is formed by directly laminating a light absorption anisotropic layer containing an organic dichroic substance with an optically anisotropic layer consisting of a liquid crystal layer, where the absorption axis of the light absorption anisotropic layer is oriented differently from the slow axis of the optically anisotropic layer, and the layers are specifically configured to satisfy certain optical and structural conditions for enhanced moisture-heat resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a pressure sensitive adhesive layer is used to bond the light absorption anisotropic layer and optically anisotropic layer, then the layers can be easily laminated, but reticulation occurs and moisture-heat resistance is degraded when exposed to high-temperature and high-humidity environments

Engineering Contradiction:

Improveease of laminationVSAvoidmoisture-heat resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent removes the pressure sensitive adhesive layer from the laminate structure, directly bonding the light absorption anisotropic layer and optically anisotropic layer without any adhesive intermediate. This extraction of the adhesive component eliminates the source of reticulation while maintaining the lamination function through direct contact between the functional layers.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the bonding function with the functional layers themselves by enabling direct lamination. The light absorption anisotropic layer and optically anisotropic layer are bonded directly to each other, combining the optical functions and structural integrity into a unified laminate without separate adhesive components.

Inventive Principle:

Principle #5Merging (Combining)

2Device complexity

If a pressure sensitive adhesive layer is used to bond the layers, then the lamination process is simplified, but wrinkles occur and performance degrades in challenging environmental conditions

Engineering Contradiction:

Improvestructure complexityVSAvoidsurface flatness

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The adhesive layer is completely removed from the laminate structure, eliminating the interface between adhesive and functional layers where wrinkles typically form. This extraction simplifies the structure to only the essential functional layers while improving surface flatness by eliminating the adhesive-induced deformation.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If an organic dichroic substance is used in the light absorption anisotropic layer, then the polarizing function is achieved, but the laminate becomes sensitive to moisture-heat degradation when bonded with adhesive

Engineering Contradiction:

Improvepolarizing functionVSAvoidenvironmental stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The adhesive layer is removed to eliminate the source of moisture-heat degradation that affects the organic dichroic substance. This extraction protects the polarizing function by eliminating the harmful adhesive interface, allowing the organic dichroic substance to maintain its performance in challenging environmental conditions.

Inventive Principle:

Principle #2Taking out (Extraction)

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 direct lamination of the light absorption anisotropic layer and optically anisotropic layer improves moisture-heat resistance, reducing wrinkles and maintaining performance in challenging environmental conditions.

Implementation Method 1

the light absorption anisotropic layer contains an organic dichroic substance

Methodology Applied

Scientific EffectDichroism: Dichroic Filter

Implementation Method 2

the optically anisotropic layer consists of a liquid crystal layer

Methodology Applied

Scientific EffectOptical anisotropy: Anisotropy

Implementation Method 3

an optically anisotropic layer consisting of a liquid crystal layer

Methodology Applied

Scientific EffectLiquid crystal phase: Liquid Crystals

Data Source

PatentUS20230213695A1Laminates, polarizing plates, and image display device

Publication Date: 2023.07.06 FUJIFILM CORP

AI summary

An object of the present invention is to provide a laminate which includes a light absorption anisotropic layer and an optically anisotropic layer and has excellent moisture-heat resistance, and a polarizing plate and an image display device which are formed of the laminate. The laminate of the present invention is a laminate including a light absorption anisotropic layer and an optically anisotropic layer, in which the light absorption anisotropic layer contains an organic dichroic substance, the optically anisotropic layer consists of a liquid crystal layer, an axial direction of an absorption axis of the light absorption anisotropic layer is different from an axial direction of a slow axis of the optically anisotropic layer, and the light absorption anisotropic layer and the optically anisotropic layer are directly laminated.