Optically Anisotropic Sheet Substrate Surface Control
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Solution Overview
Problem
Conventional optical films with liquid crystal cured layers face defects such as peeling during transfer due to surface roughness and inadequate water contact angles, leading to suboptimal performance in display devices.
Innovation Solution
An optically anisotropic sheet comprising a substrate with a surface roughness of 1.0 nm or less and a water contact angle of 70° or more, combined with a liquid crystal cured layer that satisfies specific retardation value ratios and thickness criteria, along with an optional orientation layer, to facilitate defect-free transfer and optimal optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional substrates are used for liquid crystal cured layers, then the manufacturing process is simple, but peeling defects occur during transfer
Solution Approach 1:
The patent applies parameter changes by precisely controlling the substrate surface roughness (Ra ≤ 1.0 nm) and water contact angle (≥ 70°) to achieve defect-free transfer. These parameter specifications transform the substrate surface properties to prevent peeling while maintaining manufacturing feasibility
Solution Approach 2:
The patent implements preliminary action by pre-treating the substrate surface to achieve the required roughness and hydrophobicity before applying the liquid crystal cured layer. This preliminary surface preparation ensures that when transfer occurs, the layer remains intact without peeling defects
2Reliability
If the substrate surface is made smoother to prevent peeling, then transfer defects are reduced, but the water contact angle requirement becomes harder to meet
Solution Approach 1:
The patent resolves this contradiction by changing the surface parameters to specific values: Ra ≤ 1.0 nm for smoothness and water contact angle ≥ 70° for hydrophobicity. These parameter changes simultaneously achieve both peeling resistance and manufacturability
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 enables the transfer of the liquid crystal cured layer with minimal defects, ensuring high transparency and optical performance in display devices by maintaining the integrity of the film during the transfer process.
Implementation Method 1
Optical films that include liquid crystal cured layers formed from polymerizable liquid crystals are known as such up optical films. JP 2010-537955 T discloses an optical film including a liquid crystal cured layer having reverse wavelength dispersibility.
Implementation Method 2
the liquid crystal cured layer satisfies formulas (1) and (2): Re(450)/Re(550)≦1.00 and 1.00≦Re(650)/Re(550), where Re(450), Re(550), and Re(650) represent front retardation values at wavelengths of 450 nm, 550 nm and 650 nm, respectively.
Implementation Method 3
the substrate has a surface roughness of 1.0 nm or less in a field of view of 1 μm2
Implementation Method 4
a water contact angle of 70° or more
Implementation Method 5
Optical films that include liquid crystal cured layers formed from polymerizable liquid crystals are known as such up optical films.
Implementation Method 6
liquid crystal cured layers formed from polymerizable liquid crystals
Data Source
AI summary
The present invention relates to an optically anisotropic sheet comprising a substrate and a liquid crystal cured layer laminated together, wherein the substrate has a surface roughness of 1.0 nm or less in a field of view of 1 μm2 and a water contact angle of 70° or more.