Functional Film Copolymer Adhesion for Thin Polarizing Plates
Solution Overview
Problem
Existing polarizing plates face challenges in achieving sufficient adhesion with other layers or articles due to the limitations of their main materials, particularly in reducing thickness and flexibility, as seen in the case of cyclo olefin polymer-based coating films which exhibit low birefringence but insufficient adhesiveness.
Innovation Solution
A functional film comprising a copolymer with specific repeating units represented by Formulas (I) and (II), which allows for uneven surface distribution and crosslinked reactions, enhancing adhesiveness with other layers, films, or articles, and is integrated into a polarizing plate configuration including an adhesive layer with a hydroxyl group.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a coating film is formed using a cyclo olefin polymer to reduce thickness and achieve low birefringence, then the film thickness can be reduced and optical performance is improved, but the adhesiveness with the polarizer becomes insufficient
Solution Approach 1:
The patent uses a composite material system consisting of a cyclo olefin polymer base material combined with a silane coupling agent. The silane coupling agent forms a crosslinked structure that acts as a bridge between the cyclo olefin polymer coating film and the polarizer substrate, enabling the film to maintain both thin thickness (reducing birefringence) and strong adhesiveness through chemical bonding.
2Reliability
If the main material of the film is optimized for specific functions (low birefringence), then optical performance is improved, but the adhesion with other layers deteriorates
Solution Approach 1:
The silane coupling agent serves as an intermediary substance between the cyclo olefin polymer (optimized for optical performance) and the polarizer substrate. This intermediary material has dual compatibility: it bonds chemically with the polarizer through hydroxyl groups while also being compatible with the cyclo olefin polymer matrix, thus transferring and balancing both optical and adhesive functions.
Solution Approach 2:
The patent applies local quality modification by introducing the silane coupling agent specifically at the interface region between the coating film and the polarizer substrate. This localized modification creates a gradient structure where the interface zone has enhanced adhesive properties while the bulk coating film maintains its low birefringence optical characteristics.
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 functional film achieves improved bonding with other layers and articles, enabling the creation of a polarizing plate that is both thin and flexible, suitable for display devices like LCDs and OLEDs, while maintaining optical performance.
Implementation Method 1
a copolymer including a repeating unit represented by Formula (I), and a repeating unit represented by Formula (II); and/or a crosslinked reaction product derived from the copolymer
Data Source
AI summary
The present invention provides a functional film including a copolymer that contains a repeating unit represented by Formula (I) and a repeating unit represented by Formula (II) shown in the description, or a crosslinked reaction product derived from the copolymer; a polarizing plate having this functional film; and a display device.