Polymerisable LC Medium Negative Optical Dispersion
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Solution Overview
Problem
Existing polymerisable LC media with negative optical dispersion suffer from high costs due to the use of bulky negative dispersion compounds, poor durability, and a narrow annealing temperature process window, making them unsuitable for mass production and large-scale manufacturing of thin, high-birefringence films needed for flat panel displays.
Innovation Solution
A polymerisable LC medium comprising compounds of specific formulas, which reduce the amount of negative dispersion compounds required while maintaining dispersion value, improving durability and widening the annealing temperature process window, thereby reducing costs and enhancing film properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bulky negative dispersion compounds are used to achieve negative optical dispersion, then the dispersion value is maintained, but the cost increases and durability decreases
Solution Approach 1:
The patent changes the chemical structure parameters of the negative dispersion compounds by introducing compounds of formula I with specific molecular architectures (cyclic carbonates, cyclocarbonates, and spiro compounds) that have lower bulkiness compared to prior art compounds. This structural parameter change reduces the amount needed while maintaining the negative dispersion effect and improving durability.
Solution Approach 2:
The patent creates a composite polymerisable LC medium by combining compounds of formula A (polymerisable groups) with compounds of formula I (negative dispersion compounds) in specific ratios. This composite approach allows the system to achieve negative dispersion with reduced compound amounts while the polymer matrix provides durability and stability.
2Quantity of substance
If bulky negative dispersion compounds are used, then negative optical dispersion is achieved, but the annealing temperature process window becomes narrow
Solution Approach 1:
The patent modifies the thermal parameters of the negative dispersion compounds by selecting compounds of formula I with appropriate melting points and clearing points. These compounds are designed to have modest melting points and reasonable extrapolated clearing points, which widens the annealing temperature process window and facilitates mass production.
3Reliability
If standard positive dispersion formulations are used, then durability is improved, but negative optical dispersion cannot be achieved
Solution Approach 1:
The patent introduces compounds of formula I as intermediary substances that provide negative dispersion functionality within a polymerisable LC medium. These compounds act as mediators between the polymerisable groups (formula A) and the desired negative dispersion effect, enabling the system to achieve negative dispersion while maintaining durability through the polymer matrix.
4Length of stationary object
If thicker films are used to achieve required retardation, then manufacturing is easier, but the film thickness increases which is not preferred in flat panel displays
Solution Approach 1:
The patent changes the optical parameters of the film by utilizing compounds with high birefringence values. By increasing the birefringence parameter, the required film thickness for achieving a given retardation is reduced, enabling thinner films to be manufactured with precise retardation control for flat panel display applications.
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 solution achieves improved durability, wider annealing temperature windows, and lower costs, enabling the production of thinner films with higher birefringence, suitable for large-scale manufacturing of optical and electro-optical components.
Implementation Method 1
birefringent optical films with negative optical retardation dispersion
Implementation Method 2
negative optical dispersion
Data Source
AI summary
The invention relates to a polymerizable LC medium with negative optical dispersion, a polymer film with negative optical dispersion obtainable from such a medium, and the use of the polymerizable LC medium and polymer film in optical, electro optical, electronic, semiconducting or luminescent components or devices.