Polyimide Alignment Layer Material for Liquid Crystal Display
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current liquid crystal display technologies, such as TN/STN and VA, face challenges with small viewable angles, severe brightness and color differences at large angles, and complex manufacturing processes for multiple angle alignment, which deteriorate the optic performance and increase costs.
Innovation Solution
A material for the alignment layer comprising a solvent and a polymer with a backbone of polyimide or polyamic acid, featuring a first side chain with a stronger lateral dipole moment, allowing for rotation or tilting under an electric field to achieve pre-tilt alignment of liquid crystal molecules, simplifying the manufacturing process and improving optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If polymer bumps are formed on upper and lower glass substrates by exposure development to guide liquid crystal molecules tilting, then multiple angle alignment is achieved, but the manufacturing process becomes complex and aperture ratio must be sacrificed
Solution Approach 1:
The invention extracts the alignment function from the complex multi-step process (exposure development, polymer bump formation, ITO patterning) and concentrates it into a single material component - the polyimide with specific side chain structure. This side chain contains the essential alignment information that guides liquid crystal molecules without requiring additional processing steps, thereby simplifying the manufacturing process while maintaining multiple angle alignment capability
Solution Approach 2:
The invention changes the molecular parameter of the polyimide by introducing a side chain with specific dipole moment characteristics. This parameter change enables the material to inherently provide multiple angle alignment function, eliminating the need for complex physical structuring (polymer bumps, ITO patterns) and reducing manufacturing complexity
2Adaptability or versatility
If ITO pixel electrodes are patterned to generate predetermined tilt angles for liquid crystal molecules, then multiple angle alignment is achieved, but aperture ratio is reduced and manufacturing complexity increases
Solution Approach 1:
The invention removes the need for ITO pixel electrode patterning by embedding the alignment information directly in the polyimide side chain structure. This eliminates the opaque ITO patterns that reduce aperture ratio, allowing the entire pixel area to be optically active while still achieving multiple angle alignment through the molecular structure of the alignment material
Solution Approach 2:
The invention replaces the mechanical/electrical system of ITO electrode patterning with a molecular-level chemical system. The side chain's dipole moment creates the necessary alignment forces at the molecular level, substituting the need for macroscopic electrode structures and thereby maximizing aperture ratio
3Adaptability or versatility
If ITO slits are formed on TFT side and polymerizable monomer is added to liquid crystal medium for PSVA technique, then multiple angle alignment is achieved, but the process becomes more complex and aperture ratio is sacrificed
Solution Approach 1:
The invention extracts the alignment function from the complex PSVA process (ITO slit formation, monomer addition, electric field application, UV irradiation) and consolidates it into the polyimide side chain structure. The side chain inherently provides the alignment information without requiring external fields or additional materials, thereby simplifying the manufacturing process to a single coating and drying step
Solution Approach 2:
The polyimide side chain is designed to be self-aligning through its inherent dipole moment characteristics. It automatically orients itself during the coating process without requiring external electric fields, UV irradiation, or additional processing steps, thereby eliminating the complexity of the PSVA technique while achieving the same multiple angle alignment effect
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 material enables effective multiple angle alignment with a simpler manufacturing process, maintaining alignment without immediate vanishing effects, resulting in improved contrast and reduced light leaks, thus enhancing the optical performance of liquid crystal panels.
Implementation Method 1
The first side chain has a stronger lateral dipole moment
Implementation Method 2
when an electrical field is applied, the liquid crystal molecules are rotated or tilted toward a direction parallel to the substrate
Data Source
AI summary
The present invention provides a material for alignment layer of liquid crystal display, which includes a solvent and a polymer dissolved in the solvent. The polymer includes a backbone and a first side chain linked to the backbone. The first side chain has a stronger lateral dipole moment. The material for alignment layer of liquid crystal display is characterized in that a first side chain that contains both a flexible chain segment and rigid chain segment is linked to the backbone of the polymer and the first side chain has a stronger lateral dipole moment, making it taking a rotation or tilting motion under the application of an electric field so as to effect alignment of the liquid crystal molecules in the pre-tilt angle.