Liquid Crystal Display Alignment Film Capacitance Optimization
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Solution Overview
Problem
Liquid crystal display apparatuses using negative liquid crystals face non-uniformity in display due to variations in the thickness of the alignment film, which affects light transmittance and display quality.
Innovation Solution
The liquid crystal display apparatus is designed with a specific relationship between the capacitance of the first alignment film, the liquid crystal layer, and the bias angle, where the condition −1.11≧−0.0353×C_PI/C_LC−0.0523×θ is met to suppress non-uniformity in display by appropriately setting the alignment film capacitance and bias angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative liquid crystal material is used in an FFS-mode liquid crystal display apparatus, then the liquid crystal molecules can be effectively switched by a lateral electric field, but non-uniformity in display occurs due to variations in alignment film thickness affecting light transmittance
Solution Approach 1:
The patent changes the physical parameters of the system by optimizing the relationship between alignment film capacitance (C_PI) and liquid crystal layer capacitance (C_LC), and by setting a specific bias angle range (20-40 degrees). This parameter optimization compensates for alignment film thickness variations, reducing light transmittance non-uniformity and improving display uniformity without requiring ultra-precise thickness control
Solution Approach 2:
The patent applies preliminary alignment treatment to create a bias angle between the liquid crystal molecule alignment direction and the substrate plane. This preliminary action (setting the bias angle during alignment film formation) pre-compensates for the effects of thickness variation, allowing the display to maintain uniformity even when alignment film thickness varies during manufacturing
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 effectively reduces non-uniformity in display by minimizing light transmittance variation caused by alignment film thickness non-uniformity, resulting in improved display quality.
Implementation Method 1
a first alignment film covering the insulating film and the pixel electrodes
Implementation Method 2
a liquid crystal layer held between the array substrate and the counter-substrate, and formed by a negative liquid crystal material
Implementation Method 3
switches liquid crystal molecules in a lateral electric field substantially parallel to a main surface of the array substrate
Data Source
AI summary
According to one embodiment, a liquid crystal display apparatus includes an array substrate, a counter-substrate and a liquid crystal layer formed by a negative liquid crystal material. The array substrate includes a common electrode, an insulating film, pixel electrodes each including a slit and a first alignment film. The liquid crystal layer includes liquid crystal molecules which form a bias angle in a direction substantially orthogonal to a direction of extension of the slit and which are initially aligned. The first alignment film, the liquid crystal layer and the bias angle have a relationship of−1.11≧−0.0353×C—PI/C—LC−0.0523×θ.