Reactive Mesogenic Compounds with Tolanes for High Optical Dispersion
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Solution Overview
Problem
Current reactive mesogenic compounds and polymerizable liquid crystal mixtures fail to produce anisotropic polymer films with high optical dispersion, particularly those with negative C properties and exceptionally high birefringence dispersion, which are necessary for advanced optical and electrooptical applications.
Innovation Solution
The development of reactive mesogenic compounds with a tolane group and a terminal —NCS group, which are used to create polymerizable liquid crystal mixtures that can be processed into polymer films with enhanced optical dispersion by controlling the refractive indices' wavelength dependence, specifically designing molecules with increased extraordinary refractive index dispersion while maintaining unchanged ordinary refractive index dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional reactive mesogenic compounds are used, then the polymer films can be manufactured with standard optical properties, but the optical dispersion and birefringence dispersion remain insufficient for advanced applications
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of reactive mesogenic compounds, specifically incorporating tolane groups and terminal isocyanate groups to alter the refractive index dispersion characteristics. This structural parameter change enables the material to achieve higher optical dispersion (R450/R550 ratio) while maintaining polymerizability and liquid crystalline properties, directly resolving the contradiction between manufacturing precision and material availability
Solution Approach 2:
The patent employs composite materials by creating polymerisable liquid crystal mixtures that combine the newly developed reactive mesogenic compounds with other liquid crystal components. These composite mixtures achieve enhanced optical dispersion properties (R450/R550 > 1.1) that exceed conventional single-component systems, thereby improving manufacturing precision while expanding the versatility of available RM materials for various optical applications
2Manufacturing precision
If molecules are designed with increased ne dispersion, then the optical dispersion of polymer films increases, but the molecular structure complexity increases
Solution Approach 1:
The patent applies local quality by introducing specific functional groups (tolane and terminal isocyanate) at particular positions within the molecular structure of the reactive mesogenic compounds. This localized structural modification targets the extraordinary refractive index (ne) dispersion specifically, allowing the molecule to exhibit enhanced optical dispersion properties without requiring complete structural redesign, thus resolving the contradiction between birefringence dispersion and molecular structure complexity
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the molecular structure parameters of the reactive mesogenic compounds, including the introduction of tolane groups and terminal isocyanate groups. These parameter changes are designed to specifically increase ne dispersion while controlling overall molecular complexity, enabling the achievement of high birefringence dispersion (R450/R550 > 1.1) with manageable structural complexity that remains suitable for synthesis and processing
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 resulting polymer films exhibit higher optical retardation dispersion compared to films made from existing RM mixtures, enabling improved performance in optical and electrooptical devices by achieving higher birefringence dispersion, thus expanding the pool of available RM materials for advanced applications.
Implementation Method 1
RMs can be used to make optical films, like compensation, retardation or polarisation films, e.g. for use as components of optical or electrooptical devices like LC displays, through the process of in-situ polymerisation
Implementation Method 2
The optical properties of the film can also be controlled by changing the birefringence of the mixture. This determines the necessary thickness for a given retardation at a particular angle as well as controlling the birefringence dispersion
Data Source
AI summary
The invention relates to new reactive mesogenic compounds (RM), polymerisable liquid crystal (LC) mixtures and polymers comprising them, and the use of the compounds, mixtures and polymers in optical, electrooptical, electronic, semiconducting or luminescent components or devices, in decorative, security or cosmetic applications, especially for use in polymer films having high optical dispersion.