IPS Liquid Crystal Display Alignment Layer Pretilt Control
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Solution Overview
Problem
In IPS mode liquid crystal displays, the aperture ratio is reduced, luminance is deteriorated, and response speed is low due to the arrangement of electrodes and the slow reaction of liquid crystals to electric fields.
Innovation Solution
The implementation of a liquid crystal display with a first and second electrode formed as bands on a panel, divided into domains with different polar angles for alignment control agents, and a method involving photo-polymerizable monomers or oligomers to create alignment layers that provide pretilt for faster response and improved luminance by vertically aligning liquid crystals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If all common electrodes and pixel electrodes are formed on a panel in IPS mode, then the display can achieve wide viewing angles, but the aperture ratio is reduced and luminance is deteriorated
Solution Approach 1:
The patent divides the liquid crystal layer into multiple domains with different alignment directions. Each domain is controlled by corresponding alignment layers with different pretilt angles, allowing the display to achieve wide viewing angles through domain multiplication while maintaining higher aperture ratio by using linear electrodes rather than extensive electrode patterns.
Solution Approach 2:
The patent applies different alignment properties to different regions of the liquid crystal layer. Alignment layers are designed with specific pretilt angles (e.g., 5-30 degrees) in different domains to control liquid crystal orientation locally. This allows each region to contribute optimally to viewing angle while the overall structure maintains higher luminance.
2Reliability
If liquid crystal is arranged to respond to electric fields in conventional IPS mode, then the display can function, but the response speed is low due to slow reaction of liquid crystals near the facing panel
Solution Approach 1:
The patent applies preliminary alignment to the liquid crystal layer through specially designed alignment layers before operation. These alignment layers provide pretilt angles and specific orientation that prepare the liquid crystal molecules for faster response. The alignment layers are treated to create anchoring forces that guide liquid crystal orientation, enabling quicker response when electric fields are applied during operation.
Solution Approach 2:
The patent changes the alignment parameters of the liquid crystal layer by using alignment layers with controlled pretilt angles (5-30 degrees) and specific rubbing directions. This parameter modification allows liquid crystal molecules to be pre-oriented in directions that facilitate faster response to applied electric fields, reducing the response time from conventional slow response to improved response speeds.
3Illumination intensity
If the aperture ratio is increased to improve luminance, then the display brightness improves, but the alignment control and viewing angle characteristics may be compromised
Solution Approach 1:
The patent segments the liquid crystal layer into multiple domains, each with specific alignment characteristics. This segmentation allows the use of simpler linear electrode patterns with higher aperture ratio while maintaining wide viewing angles through the combined effect of multiple domains. Each domain contributes to the overall viewing angle performance without requiring extensive electrode structures.
Solution Approach 2:
The patent uses composite alignment structures consisting of alignment layers with different pretilt angles and properties. These composite alignment systems provide both the alignment control needed for wide viewing angles and the structural simplicity that enables higher aperture ratio. The combination of different alignment layer properties creates a system that simultaneously achieves luminance and viewing angle performance.
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 enhances response speed, luminance, and viewing angle by ensuring liquid crystals are immediately tilted when an electric field is applied, reducing afterimage issues and improving aperture ratio.
Implementation Method 1
The first alignment control agent is generated by polymerizing a photo-polymerizable monomer or oligomer
Implementation Method 2
the first alignment control agent comes out of the first alignment base layer and provides alignment force to the liquid crystal
Implementation Method 3
the polarization state of light that passes through the liquid crystal becomes differentiated according to the arrangement state of the liquid crystal by optical anisotropy of the liquid crystal
Implementation Method 4
when an electric field is applied, the liquid crystal is arranged in another manner such that the polarization state of light that passes through the liquid crystal becomes differentiated
Data Source
AI summary
A liquid crystal display includes: a first panel; a second panel facing the first panel; a first electrode and a second electrode formed on the first panel; a liquid crystal layer provided between the first panel and the second panel; and a first alignment layer formed on the first panel and contacting the liquid crystal layer. The first alignment layer includes a first alignment base layer and a first alignment control agent, the first alignment base layer represents a material for vertically aligning liquid crystal of the liquid crystal layer, and the first alignment control agent comes out of the first alignment base layer and provides alignment force to the liquid crystal. Accordingly, when the liquid crystal of the IPS mode liquid crystal display has a pretilt, the liquid crystal that is near the facing panel on which a linear common electrode and a linear pixel electrode are not provided is immediately tilted according to the pretilt, and hence, the response speed is very fast and the afterimage problem of video is solved.