Uniform Particle Dispersion on Roughened Substrates
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Solution Overview
Problem
Existing methods for applying ball spacers in liquid crystal display elements face challenges in achieving uniform dispersion and maintaining a consistent cell gap, leading to potential gravity defects and compromised optical performance.
Innovation Solution
A method involving the application of a coating composition comprising microparticles, a curable resin, and a solvent on a base material with a surface roughness of 3 nm to 100 nm, followed by drying and curing, to uniformly fix particles and maintain the cell gap, using processes such as coating, molding, erosion, or physical adjustment of the base material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ball spacers are mixed with alignment film and coated on film, then the process is simple and cost is low, but the spacers cannot be uniformly dispersed
Solution Approach 1:
The invention changes the surface roughness parameter of the base material from a conventional smooth surface to a controlled rough surface with Ra of 0.01 μm to 10 μm. This parameter change enables uniform spacer dispersion while maintaining the simple coating process, as the rough surface provides anchoring sites that prevent spacer aggregation during coating and drying.
Solution Approach 2:
The invention introduces local variability in the base material surface through controlled roughness. Different regions of the rough surface provide localized anchoring effects that collectively ensure uniform spacer distribution across the entire surface, resolving the uniformity issue while keeping the process simple.
2Manufacturing precision
If column spacers are used instead of ball spacers, then uniform dispersion is achieved, but the process complexity and cost increase
Solution Approach 1:
Instead of changing the spacer shape from spherical to columnar, the invention changes the base material surface parameter to controlled roughness. This allows spherical spacers to achieve uniform dispersion through the rough surface anchoring effect, avoiding the complexity of column spacer manufacturing and alignment processes.
Solution Approach 2:
Rather than modifying the spacer geometry to achieve uniform dispersion, the invention inverts the approach by modifying the base material surface. The rough surface actively engages the spherical spacers, achieving uniform dispersion without requiring complex spacer structures or multi-step processes.
3Shape
If surface roughness is too small, then coating is smooth, but microparticles aggregate during drying
Solution Approach 1:
The invention optimizes the base material surface roughness parameter to a specific range (Ra 0.01 μm to 10 μm). This intermediate roughness value prevents microparticle aggregation during drying by providing anchoring sites, while the coating process itself maintains smoothness. The roughness is in the base material, not the final coating surface.
Solution Approach 2:
The base material surface is pre-treated to have controlled roughness before coating. This preliminary surface preparation creates anchoring sites that prevent particle aggregation during the subsequent drying process, ensuring uniform particle distribution without requiring post-processing.
4Manufacturing precision
If surface roughness is too large, then particle dispersion is improved, but optical performance deteriorates due to visible unevenness
Solution Approach 1:
The invention precisely controls the surface roughness parameter within the range of Ra 0.01 μm to 10 μm. This optimized range provides sufficient roughness for particle anchoring and uniform dispersion, while remaining below the threshold that causes visible unevenness and optical performance deterioration.
Solution Approach 2:
The roughness is localized at the micro-scale on the base material surface, providing anchoring sites for particles without creating macro-scale visible unevenness. This local quality approach maintains optical performance while achieving uniform particle distribution.
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
This approach ensures uniform particle application and fixation, enhancing particle dispersity and optical performance while simplifying the manufacturing process and preventing gravity defects in active liquid crystal devices.
Implementation Method 1
The coating composition is coated on the base material, and then dried and cured
Implementation Method 2
The coating composition comprises microparticles, a curable resin and a solvent, and the coating composition may be coated on the base material, and then dried and cured
Data Source
AI summary
The present application relates to a method of applying particles, an optical film and a method of manufacturing an active liquid crystal device. In the method of applying particles of the present application, the particles can be uniformly applied on a base material and fixed while maintaining the shape of particles. The optical film of the present invention produced by the above method can have excellent particle dispersity. A method of manufacturing an active liquid crystal device using the above method can maintain a cell gap uniformly while simplifying the manufacturing process and preventing gravity defects.