Optically Anisotropic Layer for Wide-Angle Polarization

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Solution Overview

Problem

Existing image display devices face challenges in suppressing external light reflection and allowing image light to pass through polarized sunglasses when viewed at an angle, as conventional circularly polarizing plates are insufficient, and the production of positive C films with reverse wavelength distribution retardation is complex and costly.

Innovation Solution

An optically anisotropic layer comprising a polymer and a compound with a mesogen skeleton, where the refractive indices satisfy specific conditions, is used without an orientation film, allowing for the production of a positive C plate with reverse wavelength distribution retardation, enhancing light suppression and passage through polarized lenses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a common circularly polarizing plate is provided to the display surface, then suppression of external light reflection and passage of image light through polarized sunglasses can be achieved in front direction, but suppression of external light reflection and passage of image light through polarized sunglasses cannot be achieved in tilt direction

Engineering Contradiction:

Improveviewing angle adaptabilityVSAvoidpolarization effectiveness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent combines a positive C film with reverse wavelength distribution retardation characteristics with a circularly polarizing plate to create a composite optical structure. This composite material approach enables the display surface to maintain effective external light reflection suppression and image light passage through polarized sunglasses across both front and tilt viewing directions, thereby resolving the viewing angle adaptability issue while preserving polarization effectiveness

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces a positive C film with specific retardation parameters exhibiting reverse wavelength distribution (Rth(450)/Rth(550) > 1.05) into the optical stack. By changing the optical parameters of the polarizing system through this additional film, the system achieves improved adaptability to different viewing angles while maintaining reliable polarization performance

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If an orientation film is used to produce a positive C film with reverse wavelength distribution, then the desired optical properties can be achieved, but the production process becomes complicated and costs increase

Engineering Contradiction:

Improveretardation distribution controlVSAvoidproduction process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the orientation film step from the production process. By developing a coating composition that directly forms a positive C film with reverse wavelength distribution retardation characteristics through coating and drying alone, the invention removes the complicated orientation film application step while maintaining manufacturing precision of the desired optical properties

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The coating composition is designed to self-organize and form the desired positive C film structure with reverse wavelength distribution retardation characteristics during the coating and drying process. This self-service mechanism eliminates the need for additional orientation film processing steps, thereby reducing production process complexity while achieving the required manufacturing precision

Inventive Principle:

Principle #25Self-service

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 effectively suppresses external light reflection and allows image light to pass through polarized sunglasses across a wide wavelength range when viewed at an angle, improving image visibility in image display devices without the need for orientation films, thus simplifying production and reducing costs.

Implementation Method 1

an optically anisotropic layer including a polymer and a compound having a mesogen skeleton whose orientation state is optionally fixed

Methodology Applied

Scientific EffectOptical anisotropy: Anisotropy

Implementation Method 2

refractive indices nx(A), ny(A), and nz(A) satisfy nz(A)>nx(A)≥ny(A)

Methodology Applied

Scientific EffectBirefringence: Birefringence

Data Source

PatentUS10705274B2Optically anisotropic layer and production method therefor, optically anisotropic laminate and production method therefor, optically anisotropic transfer body, polarization plate, and image display device

Publication Date: 2020.07.07 ZEON CORP

AI summary

An optically anisotropic layer including a polymer and a compound having a mesogen skeleton, wherein the polymer has a property such that a film of the polymer that is formed by a coating method using a solution of the polymer satisfies nz(P)>nx(P)≥ny(P), wherein nx(P) is a refractive index in a direction which, among in-plane directions of the film, gives a maximum refractive index, ny(P) is a refractive index in a direction which is perpendicular to the direction of nx(P) among the in-plane directions of the film, and nz(P) a refractive index in a thickness direction of the film, and the compound having a mesogen skeleton shows an in-plane retardation with reverse wavelength distribution under specific conditions.