Thin Polarizing Plate Manufacturing via Segmented Film Lamination

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Solution Overview

Problem

Existing methods for manufacturing thin polarizing plates with superior optical properties face challenges such as breakage during stretching and poor separation of PVA-based films from base layers, leading to suboptimal thickness and optical performance.

Innovation Solution

A method involving the attachment of a non-stretched PVA-based film to a base film using attractive forces or adhesives, followed by stretching and separation with protective films to achieve a thin polarizing plate with a thickness of 10 μm or less, while maintaining high optical properties like single transmittance and degree of polarization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a PVA-based film with thickness exceeding 60 μm is used for stretching, then the film can be stretched without breakage, but the thickness of the polarizing plate cannot be reduced

Engineering Contradiction:

Improvefilm stretching reliabilityVSAvoidpolarizing plate thickness

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent divides the film structure into multiple layers: a thin PVA-based film (10-60 μm) for the polarizing function and a separate base film for mechanical support during stretching. This segmentation allows the PVA film to be thin while the base film provides the necessary strength, resolving the contradiction between thinness and stretching reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a composite structure by laminating the PVA-based film with a base film having different mechanical properties. The base film serves as a support during stretching while the PVA film provides the polarizing function. This composite approach enables the final product to have both the required mechanical reliability during processing and the desired thin final thickness

Inventive Principle:

Principle #40Composite materials

2Length of moving object

If the thickness of PVA-based film is equal to or less than 60 μm prior to stretching, then the thickness can be reduced, but the degree of swelling increases and breakage occurs easily

Engineering Contradiction:

ImprovePVA film thicknessVSAvoidfilm strength during stretching

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The patent separates the functional layer (PVA film) from the structural support layer (base film). The PVA film can be made thin (10-60 μm) for the desired final thickness, while the base film provides the mechanical strength needed during stretching, preventing breakage despite the thin PVA layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The base film acts as an intermediary that provides mechanical support during the stretching process. It compensates for the reduced strength of the thin PVA film, allowing the PVA film to be stretched without breakage while maintaining the desired thin thickness

Inventive Principle:

Principle #24Intermediary (Mediator)

3Length of moving object

If coating or co-extruding method is used to manufacture PVA-based film, then thin films can be produced, but separation from base layer is difficult and optical properties deteriorate

Engineering Contradiction:

ImprovePVA film thicknessVSAvoidseparation reliability and optical properties

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent applies a release coating to the base film before lamination with the PVA film. This preliminary action ensures that separation can be easily performed later without damaging the PVA film or compromising optical properties, while still enabling thin film production

Inventive Principle:

Principle #10Preliminary action

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

This method enables the production of thin polarizing plates with superior optical properties, reduced curling, and increased manufacturing productivity, allowing for various types of polarizing plates to be manufactured in a single process.

Implementation Method 1

the stretching process may be performed through wet stretching in a solution such as an aqueous boric acid solution or an aqueous iodine solution

Methodology Applied

Scientific EffectWet stretching:

Implementation Method 2

a polyvinyl alcohol (PVA)-based polarizing film containing an iodine compound or a dichroic dye and having molecular chains oriented in a predetermined direction

Methodology Applied

Scientific EffectMolecular orientation:

Implementation Method 3

a polyvinyl alcohol (PVA)-based polarizing film containing an iodine compound or a dichroic dye

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 4

The PVA-based polarizing film may be manufactured by dyeing a PVA-based film with iodine or a dichroic dye

Methodology Applied

Scientific EffectDyeing:

Data Source

PatentUS10048417B2Thin polarizing plate and method of manufacturing the same

Publication Date: 2018.08.14 SHANJIN OPTOELECTRONICS (NANJING) CO

AI summary

There is provided a method of manufacturing a thin polarizing plate including: forming a film laminate by attaching a non-stretched polyvinyl alcohol (PVA)-based film to a non-stretched base film, using attractive force therebetween or using an adhesive; stretching the film laminate; attaching a first protective film to the PVA-based film of the stretched film laminate; and separating the PVA-based film having the first protective film attached thereto from the base film.