Polymerizable Liquid Crystal Ink Formulations for Precise Alignment
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Solution Overview
Problem
Existing polymerizable liquid crystal formulations for inkjet printing suffer from poor alignment quality and fast solvent evaporation, leading to unsuitable inkjet printing techniques due to high boiling point solvents and fast evaporation rates, which result in poor optical performance and alignment quality, especially in small areas like pixels or subpixels.
Innovation Solution
A formulation comprising 10 to 50% w/w of polymerizable liquid crystalline compounds and 50 to 90% w/w of specific organic solvents such as aliphatic ketones, cyclic ketones, alkyl ethers of ethylene glycol or propylene glycol, and alkyl esters of menthyl or aromatic solvents, which exhibit slow evaporation rates and high annealing temperatures, ensuring good alignment quality and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high boiling point solvents are used in polymerizable liquid crystal formulations, then the formulations can be processed at higher temperatures, but the solvent evaporates too fast during inkjet printing, resulting in poor alignment quality and resolution
Solution Approach 1:
The patent changes the chemical composition parameters of the solvent system by selecting specific solvents with optimized boiling points and evaporation rates. The formulation uses a combination of solvents including cyclic ketones, aliphatic ketones, and ester compounds that provide balanced evaporation characteristics, allowing sufficient time for alignment while maintaining processability at elevated temperatures.
Solution Approach 2:
The patent employs a composite solvent system comprising multiple organic solvents with different properties. The formulation combines solvents such as cyclic ketones, aliphatic ketones, and ester compounds to create a synergistic effect where the composite solvent system provides both high-temperature processability and controlled evaporation rate, resolving the contradiction between temperature stability and alignment quality.
2Productivity
If fast evaporation rates are used, then the printing process is quicker, but the alignment quality and resolution deteriorate, especially in small areas like pixels or subpixels
Solution Approach 1:
The patent optimizes the evaporation rate parameter by carefully selecting solvents with specific vapor pressure characteristics. The formulation uses solvents that evaporate at controlled rates, preventing too-rapid evaporation that would compromise resolution while maintaining efficient printing throughput. This parameter optimization allows the ink to remain fluid enough for quick deposition but viscous enough to maintain alignment during drying.
3Device complexity
If conventional solvents are used, then the formulation is simpler, but the optical performance and alignment quality are insufficient for high-resolution printing
Solution Approach 1:
The patent develops a composite solvent formulation that combines multiple organic compounds with complementary properties. The formulation includes cyclic ketones, aliphatic ketones, and ester compounds that work synergistically to provide both good optical performance and reliable alignment quality. This composite approach maintains reasonable formulation complexity while significantly improving optical performance and alignment reliability for high-resolution printing 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 formulation achieves high-resolution, flat printing profiles with good alignment quality, suitable for inkjet printing applications, particularly in small areas, enhancing optical performance and alignment of polymer films.
Implementation Method 1
polymerizing the polymerizable components of the polymerizable LC material by photopolymerization
Implementation Method 2
Their high birefringence, favourable alignment control and well-established handling in mass production make them excellent materials for improving the performance of displays
Data Source
AI summary
The present invention relates to polymerizable liquid crystalline formulations and especially to an ink formulation for inkjet printing comprising 10 to 50% w/w of one or more polymerizable liquid crystalline compounds and 50 to 90% w/w of one or more organic solvents selected from the group of aliphatic ketones, cyclic ketones, alkyl ethers of ethylene glycol or propylene glycol, alkyl esters of menthyl or aromatic solvents.