P-Type Liquid Crystal Alignment Layer Anchoring Energy Control
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Solution Overview
Problem
Liquid crystal alignment collapse in high-voltage applications leads to display defects in Transverse Bend Alignment (TBA) mode liquid crystal display devices, resulting in light leakage and reduced display quality.
Innovation Solution
The use of a p-type liquid crystal material with a bending elastic constant k33 ≤ 14 pN, alignment layers with anchoring energy ≤ 1.5×10−4 J/m2, and alignment films with fluorine-containing groups or chemisorption films to facilitate easy deformation and control of liquid crystal alignment, along with pre-tilted liquid crystal molecules and comb-shaped electrodes with tilted surfaces, to stabilize the bend alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a TBA mode liquid crystal display device uses high voltage to drive the liquid crystal, then the response speed and contrast are improved, but the liquid crystal alignment collapses causing display defects and light leakage
Solution Approach 1:
The patent changes the material parameters by selecting a p-type liquid crystal material with specific physical properties (positive dielectric anisotropy and specific bending elastic constant k33 ≤ 14 pN) and controlling the anchoring energy of alignment layers to ≤ 1.5×10−4 J/m2. These parameter changes enable the liquid crystal to maintain stable bend alignment under high voltage conditions while achieving fast response speed and high contrast display
2Stability of the object's composition
If the anchoring energy of the alignment layer is increased to stabilize liquid crystal alignment, then the alignment stability is improved, but the ease of bend deformation is reduced
Solution Approach 1:
The patent optimizes the anchoring energy parameter to a specific range (≤ 1.5×10−4 J/m2) that balances two opposing requirements: providing sufficient stability to prevent alignment collapse under high voltage, while maintaining low enough energy to allow easy bend deformation for achieving the desired liquid crystal alignment state. This precise parameter control resolves the contradiction between stability and deformability
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 configuration effectively suppresses display defects by allowing the liquid crystal layer to maintain stable bend alignment under high voltage, ensuring consistent display quality and reducing the risk of light leakage.
Implementation Method 1
the first alignment layer has an anchoring energy of not greater than 1.5×10−4 J/m2
Implementation Method 2
a liquid crystal material that constitutes the liquid crystal layer has a bending elastic constant k33 that satisfies k33≦14 pN
Implementation Method 3
a transverse electric field generated by a comb-shaped electrode is utilized to drive the liquid crystal in the homeotropic alignment mode
Data Source
AI summary
The present invention provides a liquid crystal display device that can suppress a display defect due to collapse of liquid crystal alignment. The present invention provides a liquid crystal display device comprising a liquid crystal display element including a pair of substrates and a liquid crystal layer hermetically interposed between the pair of substrates, wherein the liquid crystal layer includes a p-type liquid crystal material that is homeotropically aligned with respect to surfaces of the pair of substrates when no voltage is applied; one of the pair of substrates comprises a comb-shaped electrode and a first alignment layer configured to control alignment of the p-type liquid crystal material; the other of the pair of substrates comprises a second alignment layer configured to control alignment of the p-type liquid crystal material; and the first alignment layer has an anchoring energy of not greater than 1.5×10−4 J/m2.