Liquid Crystal Display Device Using Reactive Mesogens
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Solution Overview
Problem
Liquid crystal display devices face challenges in achieving rapid response times and minimizing defects, particularly in driving pixels quickly while maintaining low viscosity and preventing side reactions due to high reactivity of certain liquid crystal compounds.
Innovation Solution
A liquid crystal display device is designed with a liquid crystal composition comprising a cyclohexane-based liquid crystal compound and an alkenyl-based liquid crystal compound, along with reactive mesogens and difluoro terphenyl compounds, which are aligned using specific alignment layers to control reactivity and maintain low rotational viscosity, thereby enabling rapid response times without generating defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high reactivity liquid crystal compounds are used to achieve rapid response time, then response speed is improved, but side reactions occur causing defects
Solution Approach 1:
A polymerization inhibitor is introduced as an intermediary substance to suppress unwanted polymerization reactions. The inhibitor acts as a mediator between the reactive liquid crystal compounds and the environment, preventing side reactions while allowing the compounds to maintain their low viscosity and fast response characteristics. This resolves the contradiction by enabling the use of highly reactive compounds without the harmful side effects.
Solution Approach 2:
The high reactivity of the liquid crystal compounds, which initially causes harmful side reactions and defects, is converted into a beneficial property. By carefully controlling the reaction conditions and using polymerization inhibitors, the high reactivity is harnessed to achieve rapid response times while preventing defect formation. The harmful side reactions are transformed into controlled polymerization processes that enhance device performance.
2Speed
If liquid crystal compounds with low rotational viscosity are used to achieve rapid response, then response time is improved, but manufacturing precision may be compromised
Solution Approach 1:
The molecular structure parameters of the liquid crystal compounds are optimized to achieve the desired balance between low rotational viscosity and manufacturing precision. By adjusting molecular weight, chain length, and functional groups, the compounds maintain low viscosity for fast response while ensuring proper alignment and defect-free manufacturing. This parameter optimization resolves the contradiction between speed and precision.
3Manufacturing precision
If reactive mesogens are used in alignment layers to improve alignment, then alignment quality is improved, but unwanted polymerization reactions increase causing defects
Solution Approach 1:
Polymerization inhibitors are used as intermediaries to control the polymerization of reactive mesogens in the alignment layers. These inhibitors allow the reactive mesogens to polymerize and provide good alignment quality while preventing excessive or unwanted polymerization reactions that would cause defects. The inhibitors mediate between the need for alignment and the risk of defect formation.
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 a rapid response time for pixels by utilizing the low viscosity properties of the liquid crystal compounds, preventing side reactions, and reducing defects, thus enhancing the performance of liquid crystal display devices.
Implementation Method 1
maintain low rotational viscosity, thereby enabling rapid response times
Implementation Method 2
aligned using specific alignment layers to control reactivity and maintain low rotational viscosity
Implementation Method 3
Each of the first alignment layer and the second alignment layer includes at least one reactive mesogen selected from the group represented by Chemical Formula 3 and at least one difluoro terphenyl compound selected from the group represented by Chemical Formula 4, or a polymerization product thereof
Data Source
AI summary
The present disclosure relates to a liquid crystal display device including a first substrate including a first base substrate and a first alignment layer provided on the first base substrate, a second substrate including a second base substrate facing the first base substrate and a second alignment layer provided on the second base substrate. The device further includes a liquid crystal layer provided between the first substrate and the second substrate and including a liquid crystal composition. The liquid crystal layer may include a bicyclohexane liquid crystal compound and an alkenyl liquid crystal compound.