Liquid Crystal Alignment Composition for Low-Energy Photo-Alignment
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Solution Overview
Problem
Existing liquid crystal alignment methods face challenges in achieving high film strength, alignment property, and electrical properties, particularly in low-power displays, due to issues with energy requirements for alignment, haze generation, and limitations in voltage holding ratio and afterimage performance.
Innovation Solution
A liquid crystal alignment composition comprising specific repeat units and a cross-linking agent compound with silicon-containing functional groups is used, which reduces light irradiation energy, enhances alignment stability, and improves mechanical and electrical properties through a single heat treatment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a photo-alignment method is used to avoid rubbing-induced dust and ESD, then alignment cleanliness is improved, but light irradiation energy requirement increases
Solution Approach 1:
The patent modifies the chemical structure of polyimide by introducing specific repeat units (Formulas 1-9) that alter the material's photo-reactivity and anisotropy characteristics, enabling effective liquid crystal alignment with reduced light irradiation energy while avoiding rubbing-induced dust and electrical discharge
Solution Approach 2:
The invention creates a composite alignment layer by combining polyimide with specific repeat units and cross-linking agents, forming a material that achieves both low light energy requirement and high alignment stability through synergistic effects of different functional components
2Manufacturing precision
If light irradiation is increased to improve alignment property, then alignment quality is improved, but productivity decreases
Solution Approach 1:
By changing the chemical parameters of the polyimide structure (introducing specific repeat units with enhanced photo-alignment characteristics), the patent achieves high alignment quality at lower light irradiation levels, thereby maintaining productivity without compromising alignment precision
3Stability of the object's composition
If additional heat treatment is applied after light irradiation to secure alignment stability, then alignment stability is improved, but process complexity increases
Solution Approach 1:
The patent combines the heat treatment step with the light irradiation step into a single integrated process, where the modified polyimide structure allows simultaneous achievement of alignment and stability without requiring separate sequential treatments, thereby reducing process complexity
4Strength
If cross-linking agents are added to improve film strength, then mechanical strength is improved, but electrical properties deteriorate
Solution Approach 1:
The patent introduces cross-linking agents with specific functional groups (silane, oxide, carboxyl, hydroxyl, amino) at controlled concentrations and positions within the polyimide structure, creating local cross-linked regions that enhance film strength while preserving the overall electrical properties through selective and localized modification
5Ease of manufacture
If simple addition of cross-linking agent is used to prepare alignment film, then film preparation is simplified, but electrical properties at high temperature and low frequency decrease
Solution Approach 1:
The patent carefully controls the concentration, type, and distribution parameters of cross-linking agents in the composition, achieving optimal balance between ease of manufacture and high-temperature electrical properties through parameter optimization rather than complex processing
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 composition achieves improved alignment stability, high voltage holding ratio, reduced afterimage, and enhanced mechanical properties, leading to superior performance in liquid crystal displays with increased film strength and electrical properties.
Implementation Method 1
a precursor such as polyamic acid or polyamic acid ester having excellent solubility is coated, which is then heat treated at 200° C. to 230° C. to form polyimide
Implementation Method 2
a photo-alignment method is being recently studied, wherein anisotropy is induced to a polymer film by light irradiation instead of friction, and liquid crystals are arranged using the anisotropy
Data Source
AI summary
The present invention relates to a liquid crystal alignment composition that not only exhibits high degree of imidization and excellent film strength when manufacturing a liquid crystal alignment film, but also can realize improved alignment property and electrical properties, a method for preparing a liquid crystal alignment film using the same, a liquid crystal alignment film and a liquid crystal display using the same.