Thin Polarizer Manufacturing Using Auxiliary Support

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Solution Overview

Problem

Conventional methods for manufacturing thin polarizers face challenges in achieving high stretching ratios without film breakage or surface non-uniformity, particularly when using polyvinyl alcohol-based films thinner than 60 μm, as they are prone to rolling and damage during the stretching process.

Innovation Solution

A method involving the formation of an auxiliary support on both ends of an unstretched polyvinyl alcohol-based film in the transverse direction, followed by wet-stretching in the machine direction, allowing for high-ratio stretching while preventing film breakage and surface irregularities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the thickness of the polyvinyl alcohol-based film before stretching is reduced to manufacture thinner polarizers, then the thickness of the final polarizer is reduced, but the film becomes prone to rolling and breakage during stretching

Engineering Contradiction:

Improvethickness of polarizerVSAvoidfilm stability during stretching

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

A support layer is introduced as an intermediary element between the stretching mechanism and the thin polyvinyl alcohol film. This support layer provides mechanical strength during the stretching process, enabling films with initial thickness of 60 μm or less to be stretched without rolling or breakage. The support layer acts as a temporary mediator that protects the thin film during processing while allowing the desired thinness to be achieved in the final product.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If conventional coating or co-extrusion methods are used to manufacture thin polarizers, then thinner polarizers can be produced, but the polyvinyl alcohol layer is likely to be damaged or deformed during separation

Engineering Contradiction:

Improvethickness of polarizerVSAvoidoptical properties of polyvinyl alcohol film

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The structure is segmented into distinct layers: a polyvinyl alcohol layer and a support layer. This segmentation allows the support layer to bear the mechanical load during stretching while the polyvinyl alcohol layer maintains its optical properties. The clear functional division prevents damage to the polyvinyl alcohol layer that would occur in integrated coating or co-extrusion methods where separation is required.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The support layer serves as an intermediary that protects the polyvinyl alcohol layer during the stretching process. By providing mechanical support, it prevents the polyvinyl alcohol layer from being damaged or deformed, thereby preserving optical properties such as degree of polarization. The support layer can be removed or left in place depending on the application requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If the thickness of the polyvinyl alcohol-based film before stretching is reduced, then thinner polarizers can be manufactured, but the modulus per unit area increases causing easy breakage

Engineering Contradiction:

Improvethickness of polarizerVSAvoidresistance to breakage during stretching

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The support layer acts as a mediator that compensates for the reduced strength of thin polyvinyl alcohol films. By providing additional mechanical strength, it allows the use of thinner films (60 μm or less before stretching) without experiencing breakage during the stretching process. The support layer effectively decouples the thickness parameter from the strength requirement.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach enables the production of thin polarizers with a thickness of 10 μm or less, maintaining high optical properties such as single transmittance of 40-43% and a degree of polarization of 99% or higher, while enhancing productivity and preventing film rolling and breakage.

Implementation Method 1

wet stretching in a solution such as an aqueous boric acid solution or an aqueous iodine solution

Methodology Applied

Scientific EffectAbsorption (physical): Absorption (physical)

Implementation Method 2

a polyvinyl alcohol-based polarizing film which contains iodine or a dichroic dye and in which molecular chains are oriented in a specific direction

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS10101513B2Method for manufacturing thin polarizer, thin polarizer manufactured using same, and polarizing plate

Publication Date: 2018.10.16 SHANJIN OPTOELECTRONICS (NANJING) CO

AI summary

The present invention relates to a method for manufacturing a thin polarizer, the method comprising the steps of: forming an auxiliary support on both ends in the transverse direction (TD) of an unstretched polyvinyl alcohol-based film; and wet-stretching the polyvinyl alcohol-based film, which has the auxiliary support formed thereon, in the machine direction (MD) of the polyvinyl alcohol-based film, in such that the thickness of the polyvinyl alcohol-based film is 10 μm or less.