Cholesteric Liquid Crystal Film Interface Alignment for Low Haze
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Solution Overview
Problem
Stacking multiple cholesteric liquid crystal layers results in increased haze due to disturbance of molecular axis orientation at laminated interfaces, leading to light scattering.
Innovation Solution
A cholesteric liquid crystal film is designed with alternating dark and bright portions in each layer, where the dark portions in one layer are connected to those in the adjacent layer, and the distance and angle of these portions are carefully controlled to minimize alignment disorder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple cholesteric liquid crystal layers are stacked to widen the reflected wavelength range, then the wavelength range can be expanded, but the haze increases due to molecular axis orientation disturbance at interfaces
Solution Approach 1:
A polymer layer is introduced as an intermediary between adjacent cholesteric liquid crystal layers. This polymer layer has a refractive index matched to both liquid crystal layers and maintains a uniaxial orientation structure that continues the helical axis orientation from one liquid crystal layer to the next, preventing molecular axis orientation disturbance at the interface while allowing multiple layers to be stacked for expanded wavelength range.
2Adaptability or versatility
If multiple cholesteric liquid crystal layers are stacked to reflect multiple wavelengths, then the optical functionality is improved, but light scattering increases due to interface disturbances
Solution Approach 1:
The polymer layer serves as a mediator that eliminates refractive index mismatch and orientation discontinuity at layer interfaces. By matching the refractive index and maintaining continuous uniaxial orientation, the polymer intermediary prevents light scattering that would otherwise occur at the interfaces between liquid crystal layers with different helical pitches.
3Ease of manufacture
If cholesteric liquid crystal layers are brought into direct contact to reduce manufacturing cost, then the manufacturing cost is reduced, but the haze increases due to orientation disturbance at the interface
Solution Approach 1:
The polymer layer is formed in-situ between liquid crystal layers during the manufacturing process, creating a thin intermediary layer that prevents direct contact between liquid crystal layers. This approach only slightly modifies the manufacturing process while effectively preventing orientation disturbance and haze at the interfaces.
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 film achieves reduced haze by suppressing disorder in the liquid crystal alignment, enhancing optical properties.
Implementation Method 1
A cholesteric liquid crystal layer is known as a layer having properties of selectively reflecting either dextrorotatory circularly polarized light or levorotatory circularly polarized light in a specific wavelength range
Implementation Method 2
at an interface between the first cholesteric liquid crystal layer and the second cholesteric liquid crystal layer, the dark portions observed in the second cholesteric liquid crystal layer is connected to the dark portions observed in the first cholesteric liquid crystal layer
Data Source
AI summary
The present disclosure provides a cholesteric liquid crystal film including a first cholesteric liquid crystal layer having a stripe pattern in which dark portions and bright portions, which are observed with a microscope, are alternately arranged and a second cholesteric liquid crystal layer which is disposed in contact with the first cholesteric liquid crystal layer and has a stripe pattern in which dark portions and bright portions, which are observed with a microscope, are alternately arranged, in which, at an interface between the first cholesteric liquid crystal layer and the second cholesteric liquid crystal layer, the dark portions observed in the second cholesteric liquid crystal layer is connected to the dark portions observed in the first cholesteric liquid crystal layer.