Optically Anisotropic Layer Surface Roughness Control
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Solution Overview
Problem
Existing optically anisotropic layers used in optical films and polarizing plates often suffer from haze occurrence and deteriorated winding aptitude due to surface roughness, which affects transparency and performance.
Innovation Solution
An optically anisotropic layer is developed by polymerizing a polymerizable liquid crystal composition, where the surface roughness is controlled by adjusting the amplitude value at specific wavelengths through Fourier transform analysis, ensuring the amplitude value at 5.0 μm or more is 0.125 or more and at 2.0 to 2.5 μm is 0.025 or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If surface roughness is increased to improve winding aptitude, then winding aptitude is improved, but haze occurs and transparency is deteriorated
Solution Approach 1:
The patent applies parameter changes by precisely controlling the surface roughness amplitude values at different wavelengths through Fourier transform analysis. By setting specific amplitude value ranges (0.05≤L≤0.20 at 5.0μm or more, and 0.005≤L≤0.020 at 2.0 to 2.5μm), the invention optimizes the balance between winding aptitude and transparency, resolving the contradiction between improving winding performance and preventing haze occurrence.
2Ease of operation
If surface roughness is increased to improve winding aptitude, then winding aptitude is improved, but transparency is deteriorated
Solution Approach 1:
The patent employs parameter changes by establishing specific amplitude value ranges for surface roughness at different wavelengths. The controlled parameters (amplitude values at 5.0μm or more and 2.0 to 2.5μm wavelengths) are optimized to maintain transparency while improving winding aptitude, thus resolving the contradiction between operational ease and reliability.
3Ease of operation
If amplitude value at 2.0 to 2.5 μm wavelength is increased, then winding aptitude is improved, but haze occurs
Solution Approach 1:
The patent applies parameter changes by setting a specific upper limit (0.020) for the amplitude value at 2.0 to 2.5μm wavelength. This precise parameter control prevents haze occurrence while maintaining sufficient winding aptitude, resolving the contradiction between improving operational ease and preventing harmful effects.
Solution Approach 2:
The patent applies local quality by differentiating the amplitude value requirements at different wavelength ranges. By setting distinct amplitude value ranges for different wavelengths (5.0μm or more versus 2.0 to 2.5μm), the invention optimizes local surface characteristics to simultaneously achieve good winding aptitude and prevent haze, resolving the contradiction between these competing requirements.
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 solution effectively suppresses haze occurrence and improves winding aptitude, resulting in enhanced transparency and performance of optical films, polarizing plates, and image display devices.
Implementation Method 1
an optically anisotropic layer obtained by polymerizing a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound
Implementation Method 2
the polymerizable liquid crystal composition is immobilized in a liquid crystal state of a smectic phase
Implementation Method 3
an amplitude value at each wavelength determined by subjecting data of a three-dimensional surface roughness to a Fourier transform
Data Source
AI summary
An optically anisotropic layer in which the occurrence of a haze is suppressed and a winding aptitude is excellent; and an optical film, a polarizing plate, and an image display device, each having the optically anisotropic layer. The optically anisotropic layer is obtained by polymerizing a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound, in which in a case where an amplitude value at each wavelength determined by subjecting data of a three-dimensional surface roughness to a Fourier transform is defined as L, the amplitude value L at a wavelength of 5 μm or more is 0.125 or more, and the amplitude value L at a wavelength of 2.0 to 2.5 μm is 0.025 or less.