Photoreactive Mesogens Enable In-Situ Photoalignment
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Solution Overview
Problem
Current liquid crystal display technologies face challenges in achieving optimal image quality, particularly in terms of viewing-angle dependence, contrast, and response times, due to the complexity and cost of producing polyimide layers and the limitations of existing photoalignment methods, which often require additional steps and materials like polyimide or azo-group compounds.
Innovation Solution
The development of photoreactive mesogens that enable in-situ photoalignment of liquid crystals using linearly polarized light, eliminating the need for polyimide layers and simplifying the production process, while maintaining high dark state and voltage holding ratio performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polyimide layers are used for alignment, then liquid crystal alignment is achieved, but production complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the polyimide alignment layer from the display structure, replacing it with photoreactive mesogens directly incorporated into the liquid crystal mixture. This removes the complex polyimide deposition and rubbing processes while maintaining alignment functionality through photo-induced self-organization of the mesogenic molecules.
Solution Approach 2:
The patent replaces the mechanical rubbing process used with polyimide layers with an optical alignment mechanism. Linearly polarized light induces photoreactive mesogens to self-organize and align liquid crystal molecules, substituting mechanical alignment with optical field-based self-organization.
2Ease of manufacture
If photoreactive mesogens are used for in-situ photoalignment, then production process is simplified, but additional photoalignment steps are required
Solution Approach 1:
The patent merges the alignment function with the liquid crystal material itself by incorporating photoreactive mesogens into the LC mixture. This combines material functionality (alignment) with the display medium, eliminating separate alignment layers and reducing overall production steps despite adding a photoalignment treatment step.
Solution Approach 2:
The photoreactive mesogens are pre-incorporated into the liquid crystal mixture before cell assembly. The photoalignment step is performed as a preliminary treatment that activates the alignment capability already present in the mixture, rather than requiring post-assembly alignment procedures.
3Reliability
If conventional liquid crystal displays are used, then basic display function is achieved, but viewing-angle dependence and response times are poor
Solution Approach 1:
The patent changes the molecular parameters of the liquid crystal system by incorporating photoreactive mesogens with specific photophysical properties. Upon light irradiation, these mesogens undergo structural changes that modify the liquid crystal's optical parameters, enabling improved viewing-angle characteristics and faster response times while maintaining display functionality.
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
This approach simplifies the production process, reduces costs, and enhances image quality by allowing for efficient photoalignment of liquid crystals within liquid crystal displays, improving viewing-angle dependence and response times without the need for complex polyimide layers.
Implementation Method 1
photoreactive mesogens that enable in-situ photoalignment of liquid crystals using linearly polarized light
Data Source
AI summary
The invention relates to a compound of formula I, wherein R11, R21, A11, A, Z, X11, X21, Y11, Y12, Sp11, Sp21, o and p have one of the meanings as given in claim 1. The invention further relates to method of production of a compound of formula I, to the use of said compounds in LC media and to LC media comprising one or more compounds of formula I. Further, the invention relates to a method of production of such LC media, to the use of such media in LC devices, and to LC device comprising a LC medium according to the present invention. The present invention further relates to a process for the fabrication such liquid crystal display and to the use of the liquid crystal mixtures according to the invention for the fabrication of such liquid crystal display.