Polymerizable Liquid Crystal Compounds for Thin Phase Retarder Films
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Solution Overview
Problem
Existing technologies face challenges in producing high-performing phase retarders with thin optical films using liquid crystals with high birefringence, as they struggle to achieve the necessary retardation values efficiently.
Innovation Solution
Development of a liquid crystal compound with specific structural modifications, including spacer groups, naphthalene substitutions, and polymerizable units, which can be used to create LCP films with controlled molecular orientation for enhanced optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid crystals with high birefringence are used, then the necessary retardation value can be realized with small quantities of liquid crystal compounds, but the manufacturing complexity and cost increase due to the need for specific structural modifications and polymerizable groups
Solution Approach 1:
The LCP compound is divided into distinct functional segments: naphthalene core groups (providing birefringence), spacer groups (controlling molecular spacing and orientation), and polymerizable groups (enabling network formation). This segmentation allows each component to be optimized independently for its specific function while maintaining overall high birefringence with reduced material quantity.
Solution Approach 2:
The invention creates a composite liquid crystal polymer network by combining liquid crystal monomers with specific naphthalene structures and polymerizable groups. This composite structure integrates the high birefringence properties of naphthalene-based LCPs with the structural stability of cross-linked polymer networks, achieving high performance with reduced material quantity.
2Length of stationary object
If LCP materials with high birefringence are used to create thin optical films, then the film thickness can be reduced, but the manufacturing precision requirements increase to maintain uniform molecular orientation and optical properties
Solution Approach 1:
The invention modifies key parameters of the LCP compounds including the introduction of polymerizable groups that enable cross-linking, adjustment of spacer group lengths, and optimization of naphthalene core structures. These parameter changes enhance molecular orientation control and stabilize the liquid crystal phase, allowing thin film formation with uniform optical properties.
Solution Approach 2:
The liquid crystal compounds are pre-designed with built-in orientation-directing groups and polymerizable functionalities that facilitate controlled molecular alignment during film formation. The preliminary structural design ensures that upon curing, the molecules maintain uniform orientation even in thin film configurations, reducing manufacturing precision requirements.
3Reliability
If spacer groups with various substitutions are introduced to optimize LCP properties, then the birefringence and optical anisotropy are enhanced, but the synthesis complexity and manufacturing cost increase
Solution Approach 1:
The invention introduces specific substitutions at localized positions on the naphthalene core and spacer groups (such as fluorine, chlorine, or alkoxy groups at specific carbon positions) to optimize local molecular properties. This local quality enhancement improves overall optical anisotropy and birefringence while maintaining manageable synthesis complexity through targeted rather than comprehensive modification.
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 modified LCP films exhibit high birefringence, enabling the production of thinner optical films that achieve the desired retardation values, addressing the challenge of producing high-performing phase retarders with reduced material usage.
Implementation Method 1
When light passes through a phase retarder its polarization direction changes because of the birefringence and the thickness of the phase retarder
Implementation Method 2
The LCP-material may comprise only a single type of liquid crystal compound but may also comprise additional polymerizable and/or non-polymerizable compounds
Data Source
AI summary
The invention relates to novel polymerizable liquid crystals of formula (I), to LCP mixtures comprising these compounds and to their uses for optical and electro-optical devices: