PVA Polarizer Cross-Linking for Dimensional Stability

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Solution Overview

Problem

Elongated polyvinyl alcohol-based film polarizers experience shrinkage and deformation under high temperature and high humidity conditions, leading to stress on protection films and light leakage in liquid crystal displays, with existing cross-linking methods using boron compounds having limited effectiveness.

Innovation Solution

A method involving two cross-linking and elongation steps using aqueous solutions containing a polyvalent carboxylic acid compound and a boron compound, with specific ratios to ensure uniform distribution and enhanced cross-linking, thereby improving dimensional stability and reducing shrinkage and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cross-linking is performed using only a boron compound, then the process is simple, but significant width shrinkage and deformation occur under high temperature and humidity conditions

Engineering Contradiction:

Improvecross-linking process simplicityVSAvoiddimensional stability under durability conditions

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite cross-linking system combining boron compound and organic cross-linking agent (such as polyvinyl alcohol or carboxylic acid) to achieve both process simplicity and superior dimensional stability. The composite approach allows the polarizer to maintain excellent resistance to shrinkage and deformation under high temperature and humidity conditions while keeping the manufacturing process straightforward

Inventive Principle:

Principle #40Composite materials

2Reliability

If an organic cross-linking agent such as polyvalent aldehyde compound is used in addition to boron compound, then shrinkage and deformation are improved, but peculiar odor and handling stability problems occur

Engineering Contradiction:

Improveshrinkage and deformation resistanceVSAvoidpeculiar odor and handling stability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters by selecting specific organic cross-linking agents (polyvinyl alcohol or carboxylic acid compounds) that do not produce peculiar odors and maintain good handling stability. These alternatives to traditional aldehyde-based cross-linking agents provide the same shrinkage resistance benefits without the harmful side effects, enabling safe and comfortable manufacturing operations

Inventive Principle:

Principle #35Parameter changes

3Reliability

If polyvalent carboxylic acid compound and boron compound are used in cross-linking, then dimensional stability is improved, but the number of cross-linking steps increases

Engineering Contradiction:

Improvedimensional stabilityVSAvoidnumber of cross-linking steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the cross-linking functions of polyvalent carboxylic acid compound and boron compound into a unified cross-linking step or closely integrated sequential steps. This combination approach achieves superior dimensional stability through dual cross-linking mechanisms while minimizing process complexity by consolidating the treatment into essentially one operational phase with optimized timing and concentration parameters

Inventive Principle:

Principle #5Merging (Combining)

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 results in polarizers with excellent optical properties and dimensional stability, effectively reducing shrinkage and deformation under durability conditions, and allowing for a thinner polarizer design with improved handling properties.

Implementation Method 1

a first cross-linking and elongating step of cross-linking and elongating the polyvinyl alcohol-based film and the dye by using a first aqueous solution including a polyvalent carboxylic acid compound and a boron compound

Methodology Applied

Scientific EffectCross-linking: Chemical Bonding

Implementation Method 2

Methodology Applied

Scientific EffectElongation: Deformation

Implementation Method 3

a liquid crystal display is a display visualizing polarization by a switching effect of a liquid crystal

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS10114159B2Method for manufacturing polarizer and polarizer manufactured by the same

Publication Date: 2018.10.30 SHANJIN OPTOELECTRONICS (SUZHOU) CO LTD

AI summary

The present specification relates to a method for manufacturing a polarizer and a polarizer manufactured by using the same, and more particularly, to a method for manufacturing a polarizer, which includes a cross-linking and elongating step using an aqueous solution including a polyvalent carboxylic acid compound and a boric acid compound, and a polarizer manufactured by using the same.