Hydrogenated Block Copolymer Light Diffuser for Displays

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Solution Overview

Problem

Conventional polymeric display substrates, such as those made from polycarbonate, suffer from moisture absorption and optical performance limitations, particularly with short-wavelength laser light, which affects their suitability for applications like LCDs and other display systems that require high transmittance, low haze, and minimal birefringence.

Innovation Solution

A composition comprising a rigid, substantially fully hydrogenated block copolymer combined with light-diffusing particles, where the block copolymer constitutes a continuous phase and the particles form a disperse phase, offering improved optical properties with high transmittance and haze values, while minimizing moisture absorption and birefringence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polycarbonate is used as the polymeric matrix, then the material provides good mechanical strength and processability, but it exhibits high moisture absorption and poor optical performance with short-wavelength laser light

Engineering Contradiction:
Improvemoisture absorption resistanceVSAvoidoptical performance with short-wavelength light
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the chemical composition parameters of the polymeric matrix by using hydrogenated block copolymer instead of polycarbonate. This parameter change fundamentally alters the material's moisture absorption characteristics and optical properties, achieving both low moisture absorption and improved performance with short-wavelength laser light.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining hydrogenated block copolymer matrix with dispersed light-diffusing particles. This composite approach allows the matrix to provide moisture resistance while the particles contribute to optical performance, resolving the contradiction between moisture absorption resistance and optical performance.

Inventive Principle:
Principle #40Composite materials

2Strength

If polycarbonate is used as the polymeric matrix, then the material provides good mechanical strength, but it exhibits high birefringence and insufficient transmittance for high-performance display applications

Engineering Contradiction:
Improvemechanical strengthVSAvoidtransmittance and birefringence
Core Design Contradiction:
StrengthVSIllumination intensity

Solution Approach 1:

The patent changes the polymeric matrix from polycarbonate to hydrogenated block copolymer, fundamentally altering the material parameters. This change reduces birefringence and improves transmittance while maintaining adequate mechanical strength through the block copolymer's inherent properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by dispersing light-diffusing particles within the hydrogenated block copolymer matrix. This creates local variations in refractive index that improve light diffusion and transmittance properties without compromising the overall mechanical strength provided by the continuous matrix phase.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If conventional polymeric materials are used, then the manufacturing process is simple, but the optical clarity and haze control are insufficient for high-quality display substrates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidoptical clarity and haze
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent uses a composite material approach by combining hydrogenated block copolymer with light-diffusing particles. This composite structure enables superior optical clarity and haze control through the interaction between the matrix and dispersed particles, while maintaining manufacturability through standard processing techniques.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by strategically dispersing light-diffusing particles within the polymeric matrix. This creates localized optical properties that enhance overall optical clarity and control haze effectively, achieving high-quality display substrate performance without complex manufacturing processes.

Inventive Principle:
Principle #3Local quality

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 provides a polymeric display substrate with enhanced optical clarity, high transmittance, and low haze, suitable for various display devices, including LCDs, with reduced moisture absorption and minimal birefringence, addressing the limitations of traditional materials.

Implementation Method 1

a particulate light diffusing material

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentUS7980734B2Bulk light diffuser composition
Publication Date: 2011.07.19 USI CORP

AI summary

The present invention is a bulk light diffuser material based upon a hydrogenated block copolymer, but including a particulate light diffusing component. The material may be in the form of a film, a sheet or a molded article. When present as a sheet having a thickness of 2 millimeters, the sheet has a percent total transmittance of at least 50% and a haze of at least 70%, measured according to the American Society for Testing and Materials (ASTM) standard D 1003.