Optical Film Colored Layer Light Resistance
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Solution Overview
Problem
Existing optical films used in display devices face challenges with long-term durability, color correction functionality, and productivity during roll-to-roll processing, particularly due to the low light and heat resistance of functional dyes and wavelength selective absorption dyes.
Innovation Solution
An optical film comprising a sheet-like transparent substrate with a colored layer made of a cured product containing a dye, an energy radiation-curable compound, a photoinitiator, and a radical scavenger. The colored layer includes specific dye materials with defined absorption spectra and an ultraviolet shielding layer to enhance light and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a color correction layer is provided on a film having an antireflection layer, then color purity is improved and luminance efficiency is maintained, but the light resistance of functional dyes decreases leading to reduced durability
Solution Approach 1:
The invention uses a composite material system consisting of multiple specific dyes (first coloring material with λmax 470-530nm and FWHM 30-60nm, second coloring material with λmax 560-620nm and FWHM 30-60nm, and third coloring material with lowest transmittance in 650-780nm range) combined in specific proportions to achieve both high color purity and improved light resistance compared to conventional single-dye systems
Solution Approach 2:
The invention changes the optical parameters of the color correction layer by selecting dyes with specific absorption characteristics (wavelength ranges and full width at half maximum values) to optimize both color purity and stability under light irradiation, rather than using conventional dyes with unspecified parameters
2Ease of manufacture
If conventional dyes are used in the color correction layer, then color correction functionality is achieved, but light and heat resistance are insufficient reducing long-term durability
Solution Approach 1:
The invention employs a composite dye system where multiple coloring materials work synergistically: the first and second coloring materials provide color correction in blue and red regions respectively, while the third coloring material enhances stability by absorbing in the deep red region, collectively achieving both manufacturability and superior light/heat resistance
Solution Approach 2:
The third coloring material acts as an intermediary that absorbs excess energy in the 650-780nm range, protecting the first and second coloring materials from degradation while maintaining overall color correction functionality
3Productivity
If roll-to-roll processing is used for manufacturing, then productivity is improved, but surface hardness requirements reduce the choice of binder materials
Solution Approach 1:
The invention specifies precise optical parameters for the coloring materials (wavelength of maximum absorption and full width at half maximum) that enable both roll-to-roll processing compatibility and adequate surface hardness, eliminating the need for complex post-processing while maintaining productivity
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 optical film achieves improved light resistance, heat resistance, and color correction functionality, enabling long-term durability and high display quality without the need for a gas barrier layer, while maintaining productivity through roll-to-roll processing.
Implementation Method 1
a colored layer made of a cured product containing a dye (A), an energy radiation-curable compound (B), a photoinitiator (C), and a radical scavenger (D)
Implementation Method 2
an energy radiation-curable compound (B), a photoinitiator (C)
Implementation Method 3
a radical scavenger (D)
Implementation Method 4
the first coloring material has a wavelength of maximum absorption within a range of 470 to 530 nm, and a full width at half maximum of an absorption spectrum of 15 to 45 nm
Implementation Method 5
at least one of the transparent substrate and the functional layer has an ultraviolet shielding rate of 85% or higher
Data Source
AI summary
An optical film includes a sheet-like transparent substrate, and a colored layer and a functional layer formed on the transparent substrate. The colored layer is made of a cured product containing a dye, an energy radiation-curable compound, a photoinitiator, and a radical scavenger. The dye contains at least one of a first coloring material, a second coloring material, and a third coloring material. When the infrared absorption spectrum peak intensity of the colored layer in the range of 780 to 825 cm−1 is A and the infrared absorption spectrum peak intensity of pentaerythritol tetraacrylate in the range of 780 to 825 cm−1 is B, A/B is 0.01 or more and 0.25 or less. At least one of the transparent substrate and the functional layer has an ultraviolet shielding rate of 85% or higher as measured according to JIS L 1925.