Mesogenic Compounds for Blue Phase Liquid Crystal Displays
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Solution Overview
Problem
Liquid crystal media in the blue phase for electro-optical displays face challenges with high operating voltages, temperature-dependent voltage variations, and moderate reliability, limiting their applicability due to narrow temperature range and sensitivity to temperature changes.
Innovation Solution
A mesogenic media comprising a dielectrically positive component with specific compounds that stabilize the blue phase over a wide temperature range, reducing operating voltage and improving voltage holding ratio (VHR) stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid crystal media are used in the blue phase for electro-optical displays, then switching times are faster and optical viewing angle is wider, but operating voltages are high and vary dramatically with temperature
Solution Approach 1:
The patent modifies the chemical composition parameters of the liquid crystal media by introducing specific compounds (formula I with L11 groups and formula II with X2 groups) to change the phase behavior and electro-optical properties. This results in a blue phase that persists over a wider temperature range with more stable and lower operating voltages while maintaining fast switching characteristics.
Solution Approach 2:
The patent creates a composite liquid crystal media by combining multiple components: compounds of formula I (with L11 aromatic/alicyclic rings and various substituents R1-R6), compounds of formula II (with X2 groups), and optionally compounds of formula III. This composite approach stabilizes the blue phase across a broader temperature range and improves voltage stability.
2Temperature
If liquid crystal media operate at higher temperatures, then the blue phase range is extended, but operating voltage increases dramatically
Solution Approach 1:
The patent systematically varies chemical parameters including the L11 group structures (aromatic and alicyclic rings with hetero atoms), substituent types (R1-R6 representing various functional groups), and X2 group configurations to optimize the balance between blue phase temperature stability and voltage characteristics. This enables operation at elevated temperatures without dramatic voltage increases.
3Ease of manufacture
If conventional liquid crystal media are used, then manufacturing is simpler, but reliability is moderate with VHR below 90%
Solution Approach 1:
The patent develops a multi-component liquid crystal composition that maintains manufacturing simplicity while significantly improving reliability. The composite nature of the media (combining formula I, II, and III compounds) provides enhanced voltage holding ratio (VHR) while preserving ease of manufacture through standard liquid crystal processing techniques.
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 reduced operating voltages, minimized temperature dependency of voltages, and enhanced reliability by extending the blue phase range, making the liquid crystal media more suitable for demanding display applications.
Implementation Method 1
the displays of DE 102 17 273.0 and WO 2004/046 805 are much easier to manufacture. However, the liquid crystal media described in these patent applications mentioned still require operating voltages, which are not low enough for some applications. Further the operating voltages of these media vary with temperature, and it is generally observed, that at a certain temperature the voltage dramatically increases with increasing temperature.
Implementation Method 2
A mesogenic media comprising a dielectrically positive component with specific compounds that stabilize the blue phase over a wide temperature range, reducing operating voltage and improving voltage holding ratio (VHR) stability.
Data Source
AI summary
The instant invention relates to mesogenic compounds of formula (I) compounds of formula (I) wherein the parameters are as specified in the text, to mesogenic media comprising one or more of these compounds, preferably to mesogenic media showing a blue phase and their use in electro-optical light modulation elements and their respective use in displays, as well as to such devices.