Fumaric Acid Diester Resin Wavelength Dispersion
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Solution Overview
Problem
Polycarbonate-based optical compensation films exhibit high wavelength dispersion, leading to lower contrast and viewing angle characteristics, especially in the short-wavelength region, and existing fumaric acid diester-(meth)acrylate copolymers have insufficient wavelength dispersion properties.
Innovation Solution
A fumaric acid diester resin is developed, comprising a fumaric acid diester residue unit and a (meth)acrylic acid ester residue unit, specifically formulated to reduce wavelength dispersion, improving contrast and viewing angle characteristics by controlling the R450/R550 ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polycarbonate resin with aromatic component is used to form stretched film, then the film can be formed with good mechanical properties, but the wavelength dispersion of retardation increases significantly
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by using fumaric acid diester as the base polymer and incorporating specific (meth)acrylic acid ester units with carefully controlled structures (Formulas 1 and 2). This chemical parameter change reduces the aromatic content and modifies the polymer chain structure, thereby reducing wavelength dispersion while maintaining mechanical properties through the specific molecular weight and composition ratios defined in the patent.
Solution Approach 2:
The patent creates a composite resin system by combining fumaric acid diester units with specific (meth)acrylic acid ester units in a copolymer structure. This composite approach allows the material to inherit the good mechanical properties of the fumaric acid diester base while the incorporated (meth)acrylic acid ester units provide control over wavelength dispersion characteristics through their specific molecular structures and ratios.
2Strength
If aromatic-structure polymers are used, then good mechanical strength and film-forming ability are achieved, but the R450/R550 ratio becomes greater than 1.1, leading to lower contrast in short-wavelength region
Solution Approach 1:
The patent changes the chemical composition by limiting aromatic content and using specific non-aromatic or low-aromatic (meth)acrylic acid ester units with controlled structures. This parameter change reduces the R450/R550 ratio below 1.1, eliminating the harmful effect of poor contrast in the short-wavelength region while maintaining adequate film-forming ability through the fumaric acid diester base polymer.
3Manufacturing precision
If existing fumaric acid diester-(meth)acrylate copolymer is used, then some wavelength dispersion improvement is achieved, but the R450/R550 ratio is still insufficient for high-contrast display requirements
Solution Approach 1:
The patent further refines the composition parameters by specifying precise structural requirements for the (meth)acrylic acid ester units (Formulas 1 and 2), including controlled alkyl chain lengths, cyclic alkyl groups, and specific functional groups. This refined parameter control achieves R450/R550 ratio below 1.1 while maintaining good contrast and viewing angle characteristics across the visible spectrum.
Data Source
AI summary
The present invention provides a resin which has low wavelength dispersion R450/R550 and is capable of improving the viewing angle characteristics and contrast over a wide wavelength range; and a film which uses this resin. A fumaric acid diester resin according to the present invention contains a fumaric acid diester residue unit that is represented by formula (1) and a (meth)acrylic acid ester residue unit that is represented by formula (2).