Liquid Crystal Composition Photostability and Response Speed
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Solution Overview
Problem
Liquid crystal display devices face challenges in achieving high voltage holding ratio and high-speed response characteristics due to the poor photostability of certain compounds used in the liquid crystal layer, which are deteriorated during ultraviolet exposure processes, leading to decreased performance.
Innovation Solution
Incorporating a liquid crystal composition that includes compounds represented by Formula 1 and reactive mesogens, such as those described by Formula RM1 and RM2, which provide improved photostability and thermal stability, while excluding compounds like those in Formula A and B that are prone to deterioration, to maintain the voltage holding ratio and enhance response characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If compounds represented by Formula A are used in the liquid crystal layer, then response speed is improved, but photostability deteriorates during ultraviolet exposure
Solution Approach 1:
The patent changes the chemical structure parameters of the liquid crystal compounds by introducing compounds with specific molecular structures (Formula 1, 1-1, 1-2) that have different photostability characteristics compared to conventional compounds (Formula A). This structural parameter change allows maintaining fast response speed while improving resistance to ultraviolet-induced deterioration
Solution Approach 2:
The patent creates a composite liquid crystal composition by combining multiple liquid crystal compounds (Formula 1, 1-1, 1-2) with reactive mesogens (Formula RM1, RM2) in specific ratios. This composite approach synergistically combines the fast response characteristics of certain compounds with the improved photostability of others, achieving both speed and reliability
2Ease of manufacture
If conventional liquid crystal compounds are used, then manufacturing is simpler, but voltage holding ratio decreases due to deterioration
Solution Approach 1:
The patent modifies the chemical composition parameters of the liquid crystal layer by selecting specific compounds (Formula 1, 1-1, 1-2) that inherently resist ultraviolet degradation. This changes the material parameters to maintain voltage holding ratio without complicating the manufacturing process, as the new compounds are used in the same ultraviolet exposure workflow
Solution Approach 2:
The patent replaces conventional liquid crystal compounds that deteriorate during ultraviolet exposure with more stable alternative compounds. This substitution is analogous to replacing short-lived, degradation-prone materials with longer-lived, stable materials, maintaining manufacturing simplicity while improving long-term reliability
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 proposed solution results in a liquid crystal display device with improved voltage holding ratio and high-speed response characteristics, ensuring better reliability and performance by using stable compounds that resist deterioration during ultraviolet exposure.
Implementation Method 1
the liquid crystal layer includes at least one compound represented by Formula 1 below, and the liquid crystal layer does not include a compound represented by Formula A below
Implementation Method 2
the liquid crystal layer disposed between the display panel and the counter display panel and having negative dielectric anisotropy
Data Source
AI summary
A liquid crystal display device comprises a display panel including a first base substrate, a switching element disposed on the first base substrate, a color filter layer disposed on the switching element, and a pixel electrode disposed on the color filter layer; a counter display panel including a second base substrate and a common electrode disposed on the second base substrate and facing the display panel; a liquid crystal layer disposed between the display panel and the counter display panel and having negative dielectric anisotropy, wherein the liquid crystal layer includes at least one compound represented by Formula 1 below, and the liquid crystal layer does not include a compound represented by Formula A below; and a light-blocking spacer disposed on the display panel and including an area overlapping the switching element, and maintaining the thickness of the liquid crystal layer.