Thin Polarizer Manufacturing via Stretched PVA-Polymer Laminate
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Solution Overview
Problem
Current methods for manufacturing thin polarizers face challenges in achieving a thickness of 10 µm or less while maintaining superior optical characteristics and preventing film breakage, as the degree of orientation of the polyvinyl alcohol-iodine complex is difficult to improve and the thickness of polyvinyl alcohol-based films is limited by the risk of breakage during stretching.
Innovation Solution
A method involving the formation of a laminate by attaching a non-stretched polyvinyl alcohol-based film to a non-stretched polymer film, stretching the laminate with a specific ratio to ensure the polyvinyl alcohol-based film has a thickness of 60 µm or less before and 10 µm or less after stretching, using a wet or dry stretching process within a controlled temperature range, and applying iodine or dichroic dye to enhance optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of polyvinyl alcohol-based film is reduced to manufacture thin polarizer, then the thickness of polarizer is reduced, but the film breaks during stretching process
Solution Approach 1:
A polymer film is introduced as an intermediary carrier substrate to support the thin polyvinyl alcohol-based film during stretching. The polymer film has higher mechanical strength than the thin PVA film, preventing breakage during the stretching process. The laminate structure allows the thin PVA film to be stretched to 10 µm or less thickness while the polymer film provides the necessary mechanical support.
Solution Approach 2:
The invention uses a composite laminate structure combining polyvinyl alcohol-based film and polymer film. The composite structure leverages the optical properties of PVA (for polarization) and the mechanical properties of polymer (for strength during processing). This composite approach enables manufacturing of thin polarizers that would be impossible with PVA film alone.
2Manufacturing precision
If the degree of orientation of polyvinyl alcohol-iodine complex is increased to improve optical characteristics, then optical characteristics are improved, but it is difficult to improve the orientation
Solution Approach 1:
The invention changes the mechanical parameters of the stretching process, specifically using a stretching ratio of 5 times or more in the machine direction. This high stretching ratio significantly increases the degree of orientation of the polyvinyl alcohol-iodine complex, improving optical characteristics such as degree of polarization and single transmittance. The parameter change from conventional stretching to high-ratio stretching resolves the difficulty in improving orientation.
3Reliability
If the thickness of polyvinyl alcohol-based film is 60 µm or greater before stretching, then the film does not break during stretching, but the thickness of polarizer cannot be reduced to 10 µm or less
Solution Approach 1:
The invention segments the functional requirements into two separate films: the polyvinyl alcohol-based film provides the optical function (polarization) and the polymer film provides the mechanical function (strength). This segmentation allows the PVA film to be made thin (for final polarizer thickness) while the polymer film maintains structural integrity during processing. The laminate structure enables independent optimization of each film's thickness for its specific function.
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 allows for the production of thin polarizers with a thickness of 10 µm or less, achieving a high degree of polarization and minimal film damage, with improved optical characteristics and stability in the stretching process.
Implementation Method 1
attaching the non-stretched polymer film and the non-stretched polyvinyl alcohol-based film to each other by using attractive force therebetween or an adhesive
Implementation Method 2
stretching the laminate such that L, expressed by Formula 1 below, satisfies 0 ≤ L ≤ 0.125
Implementation Method 3
polyvinyl alcohol-based polarizing films, containing an iodine-based compound or a dichroic dye
Data Source
Figure 1~2
AI summary
Provided is a stretched laminate for manufacturing a thin polarizer while increasing the degree of orientation of a polyvinyl alcohol-iodine complex without problems such as breakage. In addition, there are provided a method of manufacturing a thin polarizer having superior optical characteristics by using the stretched laminate, a thin polarizer manufactured by the method, and a polarizing plate including the thin polarizer.