Liquid Crystal Capsule Dispersion for Contrast Optimization
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Solution Overview
Problem
Liquid crystal display devices with liquid crystal capsules face issues of particle agglomeration leading to reduced contrast ratio and increased black level due to non-uniform dispersion, limiting the optimization of optical properties.
Innovation Solution
A liquid crystal layer with liquid crystal capsules having a shell and core structure, where the gap distance between adjacent capsules is between 20 nm and 0.3 times the capsule diameter, optimized through the use of water-soluble and fat-soluble materials and controlled shell thickness to prevent scattering and agglomeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If liquid crystal capsules are dispersed in the binder to form a liquid crystal layer, then the device thickness and weight are reduced compared to traditional glass substrate structures, but particle agglomeration occurs leading to reduced contrast ratio and increased black level
Solution Approach 1:
The patent changes the size parameter of liquid crystal capsules to be smaller than the wavelength of visible light (specifically 380-780 nm), which prevents scattering and reduces particle agglomeration effects. This parameter optimization resolves the contradiction by maintaining uniform dispersion while achieving the desired weight reduction.
Solution Approach 2:
The patent introduces a shell structure as an intermediary layer around the liquid crystal core. This shell prevents direct interaction between adjacent liquid crystal capsules, reducing agglomeration and maintaining uniform dispersion in the binder, thereby preserving contrast ratio while enabling the lightweight liquid crystal layer structure.
2Illumination intensity
If the size of liquid crystal capsules is reduced below the wavelength of visible light to improve transmittance, then optical properties are improved, but particle agglomeration becomes more frequent reducing contrast ratio
Solution Approach 1:
The patent optimizes the capsule size parameter to be within the visible light wavelength range (380-780 nm), specifically controlling it to be smaller than the wavelength to prevent scattering. This parameter optimization simultaneously achieves high transmittance while minimizing agglomeration effects that would reduce contrast ratio.
Solution Approach 2:
The patent creates a composite structure with a shell material surrounding the liquid crystal core. This composite design prevents direct contact between liquid crystal capsules, reducing agglomeration frequency while maintaining the small size necessary for high transmittance.
3Reliability
If shell thickness of liquid crystal capsules is increased to prevent agglomeration, then particle agglomeration is reduced improving contrast ratio, but maximum transmittance of white level decreases
Solution Approach 1:
The patent optimizes the shell thickness parameter to be within the range of 1-20 nm. This optimized thickness is sufficient to prevent agglomeration and maintain contrast ratio while being thin enough to minimize light absorption, thereby preserving high white level transmittance.
Solution Approach 2:
The patent applies the shell structure selectively with locally optimized thickness (1-20 nm) only where needed to prevent capsule-agglomeration, rather than using a uniform thick layer throughout. This local optimization maintains contrast ratio while minimizing impact on overall transmittance.
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 configuration enhances the contrast ratio and reduces the black level by preventing scattering, maximizing the density of liquid crystal capsules and improving transmittance and display quality.
Implementation Method 1
When a size of the liquid crystal capsules in the particle agglomeration (an average diameter of the particle agglomeration) is greater than a wavelength of a visible ray, a scattering may occur
Implementation Method 2
The LCD device displays an image using an optical anisotropy and a polarization property of a liquid crystal molecule
Implementation Method 3
The LCD device displays an image using an optical anisotropy and a polarization property of a liquid crystal molecule
Data Source
AI summary
A liquid crystal display device includes: a substrate; a thin film transistor in a pixel region over the substrate; a common electrode over the thin film transistor; a pixel electrode connected to the thin film transistor; and a liquid crystal layer including a plurality of liquid crystal capsules over the common electrode and the pixel electrode, wherein each of the plurality of liquid crystal capsules includes a shell and a core having a plurality of liquid crystal molecules therein, and wherein a gap distance between the liquid crystal molecules in adjacent liquid crystal capsules is equal to or greater than 20 nm and equal to or smaller than 0.3 times of a capsule diameter of the adjacent liquid crystal capsules.