Liquid Crystal Alignment Solution for Residual Image Reduction
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Solution Overview
Problem
Conventional liquid crystal display devices face issues with residual images due to incomplete separation of ionic electrons from the alignment layer when the voltage is interrupted, affecting the performance and reliability of the display.
Innovation Solution
A liquid crystal alignment solution comprising a combination of first and second polyimide-polyamide acids with different imidization rates, where the second polyimide-polyamide acid has a side chain, is used to form a stable pre-tilt angle and uniform orientation, enhancing the voltage holding ratio and reducing residual direct current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single polyimide-polyamide acid is used to form the alignment layer, then the manufacturing process is simple, but the pre-tilt angle stability and voltage holding ratio are insufficient
Solution Approach 1:
The patent uses a composite alignment solution containing two different polyimide-polyamide acids with distinct imidization rates. The first polyimide-polyamide acid (with imidization rate ≤50%) provides stable pre-tilt angle, while the second polyimide-polyamide acid (with imidization rate ≥50%) ensures uniform orientation and high voltage holding ratio. This composite material approach resolves the contradiction by combining materials with complementary properties to achieve both reliability and performance.
2Reliability
If conventional polyimide materials are used, then the chemical resistance and thermal stability are good, but residual images occur due to incomplete separation of ionic electrons
Solution Approach 1:
The patent changes the chemical composition parameters of the alignment layer by incorporating two polyimide-polyamide acids with different imidization rates and molecular structures. This parameter change modifies the surface properties and charge separation characteristics of the alignment layer, enabling more effective separation of ionic electrons and reducing residual image effects while maintaining the inherent chemical resistance and thermal stability of polyimide materials.
3Manufacturing precision
If the imidization rate is increased to improve orientation uniformity, then the rubbing property improves, but the pre-tilt angle stability decreases
Solution Approach 1:
The patent segments the alignment solution into two distinct polyimide-polyamide acid components with different imidization rates. The first component (lower imidization rate ≤50%) is responsible for providing stable pre-tilt angle, while the second component (higher imidization rate ≥50%) is responsible for ensuring uniform orientation and good rubbing properties. This segmentation allows each component to optimize its specific function without compromising the other, resolving the contradiction between orientation uniformity and pre-tilt angle stability.
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 results in a liquid crystal display device with improved pre-tilt angle stability, high voltage holding ratio, reduced residual direct current, and enhanced reliability, addressing the issue of residual images and improving overall display performance.
Implementation Method 1
The orientation of liquid crystal molecules is changed as an electric field changes so as to control the light transmitted through the liquid crystal layer to produce an image. The material which can orient liquid crystal molecules at a pre-tilt angle is called an alignment layer.
Implementation Method 2
Conventionally, when a voltage is applied to a liquid crystal display device, the ionic electrons are absorbed by the alignment layer.
Data Source
AI summary
A liquid crystal alignment solution is provided. The liquid crystal alignment solution includes a first polyimide-polyamide acid and a second polyimide-polyamide acid. The first polyimide-polyamide acid is represented by formula (A),and the second polyimide-polyamide acid is represented by formula (B),in which T1, T2, T3 and T4 are each independently a tetravalent residue of a tetracarboxylic acid dianhydride; D1, D2, D3 and D4 are each independently a divalent residue of a diamine; and m, n, p and q are each independently an positive integer, wherein m/(m+n)≦0.5 and p/(p+q)≧0.5.