Liquid Crystal Cell with Conductivity Control for Haze Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing normally transparent mode liquid crystal elements, such as PDLCs, face issues with high driving voltage and fluctuating residual haze levels, which affect their haze characteristics and transmittance variability.
Innovation Solution
A liquid crystal cell design with two substrates and a liquid crystal layer that exhibits a current density peak after 2 ms, utilizing non-reactive liquid crystals with specific dielectric and refractive index anisotropy, and a conductivity control agent to achieve excellent transmittance-variable characteristics and haze characteristics in transparent and scattering modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PDLC (polymer dispersed liquid crystal) is used to achieve normally transparent mode, then transparent mode is implemented, but driving voltage becomes high and residual haze level fluctuates
Solution Approach 1:
The patent changes the physical and chemical parameters of the liquid crystal composition by specifying precise ranges for dielectric constant anisotropy (Δε: 3-15), refractive index anisotropy (Δn: 0.1-0.3), and conductivity control agent concentration (0.1-10 wt%). These parameter optimizations enable the liquid crystal cell to operate at lower driving voltages while maintaining stable transparent and scattering modes, resolving the high voltage and residual haze issues of conventional PDLC.
Solution Approach 2:
The patent uses a composite liquid crystal composition combining non-reactive liquid crystals with specific dielectric and refractive properties, conductivity control agents (ionic compounds or reactive monomers), and optionally dichroic dyes. This composite material approach creates a system that achieves stable optical switching with reduced driving voltage and minimized residual haze, overcoming the limitations of simple PDLC formulations.
2Illumination intensity
If PDLC is used to achieve normally transparent mode, then transparent mode is implemented, but haze characteristic degrades depending on exposure characteristics
Solution Approach 1:
The patent incorporates conductivity control agents that provide feedback mechanisms to stabilize the liquid crystal orientation state. The ionic compounds or reactive monomers adjust the electrical properties dynamically, maintaining consistent haze characteristics across different exposure conditions and preventing degradation over time while preserving the normally transparent mode.
Solution Approach 2:
By optimizing the dielectric constant anisotropy and refractive index anisotropy parameters within specific ranges, the patent creates a liquid crystal composition that maintains stable optical properties. These parameter controls ensure consistent haze characteristics regardless of exposure duration or intensity, resolving the degradation issue observed in conventional PDLC.
3Illumination intensity
If current density peak time is adjusted to after 2 ms, then transmittance-variable characteristics improve, but device response time increases
Solution Approach 1:
The patent optimizes the liquid crystal composition parameters (dielectric constant anisotropy, refractive index anisotropy, conductivity control agent concentration) to achieve the desired current density peak time of 2-8 ms. This parameter optimization balances the transmittance-variable characteristics with acceptable response time, creating an optimal trade-off for the specific application 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 liquid crystal cell effectively switches between transparent and scattering modes with improved haze characteristics and transmittance variability, reducing the impact of driving voltage and maintaining physical properties, suitable for various light modulation devices.
Implementation Method 1
utilizing non-reactive liquid crystals with specific dielectric and refractive index anisotropy
Implementation Method 2
utilizing non-reactive liquid crystals with specific dielectric and refractive index anisotropy
Implementation Method 3
a conductivity control agent to achieve excellent transmittance-variable characteristics and haze characteristics
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A liquid crystal cell and a manufacturing method thereof and a use thereof are provided in the present disclosure. The liquid crystal cell is in a normally transparent mode, and has excellent transmittance-variable characteristics in a transparent mode and a scattering mode and excellent haze characteristics in the scattering mode. Such liquid crystal cell may be applied to various light modulation devices, such as a smart window, a window protective film, a flexible display element, a light shielding plate for transparent displays, an active retarder for 3D image displays or a viewing angle control film.