Photoaligned Liquid Crystal Display Alignment Layer

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Solution Overview

Problem

Current liquid crystal display devices face challenges in precisely controlling the initial alignment of liquid crystals, leading to difficulties in achieving improved response speed and viewing angles, particularly due to the limitations of the rubbing method and insufficient anchoring energy in photoalignment methods.

Innovation Solution

A liquid crystal display device is developed with a photoaligned alignment layer that includes a base layer and a regulator formed by photopolymerizing a monomer or oligomer, allowing for precise control of the polar and azimuthal angles of the liquid crystal alignment, which enhances the alignment force and reduces production time and costs by integrating both layers in a single process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the rubbing method is used to align the liquid crystal, then the alignment can be achieved, but it is difficult to precisely control the initial alignment state and provide different pre-tilts for each fine region

Engineering Contradiction:
Improvealignment control precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical rubbing method with a photoalignment method using UV irradiation. The alignment layer contains photopolymerizable monomers that undergo polymerization when exposed to UV light, creating anchoring regions that precisely control liquid crystal orientation without mechanical contact, thereby achieving precise alignment control while simplifying the manufacturing process

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies local quality by creating different alignment characteristics in different regions of the alignment layer. By controlling UV irradiation patterns and using monomers with different properties in specific regions, the invention enables different pre-tilt angles and alignment directions for different fine regions, achieving spatially varying alignment precision

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the photoalignment method is used to align the liquid crystal, then the alignment can be achieved with precise control, but the anchoring energy is not sufficient enough

Engineering Contradiction:
Improvealignment control precisionVSAvoidanchoring energy
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent uses composite materials by combining photopolymerizable monomers with liquid crystal materials in the alignment layer. The monomers polymerize under UV irradiation to form a network structure that provides strong anchoring energy, while the liquid crystal components maintain precise alignment control, achieving both high anchoring strength and precise alignment

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies parameter changes by utilizing the phase transition and polymerization properties of photopolymerizable monomers. When UV light is applied, the monomers undergo chemical transformation from liquid to polymer network, dramatically increasing anchoring energy while maintaining the alignment structure established during the liquid phase

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If multiple processes are used to form alignment layers, then the alignment quality can be improved, but the production time and costs increase

Engineering Contradiction:
Improvealignment qualityVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent merges multiple alignment layer formation processes into a single photopolymerization step. By incorporating all necessary alignment components (monomers, liquid crystal materials, and alignment-directing groups) into one coating layer that is subsequently UV-cured, the invention achieves high alignment quality while significantly reducing production time and costs compared to multi-step processes

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2338084B1Liquid crystal display device
Publication Date: 2018.03.21 SAMSUNG DISPLAY CO LTD
  • EP2338084B1 patent drawingFigure 1
  • EP2338084B1 patent drawingFigure 2
  • EP2338084B1 patent drawingFigure 3~4

AI summary

A liquid crystal display device and a method for manufacturing the same are disclosed. In an embodiment of the present invention, a liquid crystal display device and a method of manufacturing the liquid crystal display device includes a first substrate that has a first electrode formed thereon, a second substrate that faces the first substrate, a liquid crystal layer that is formed between the first substrate and the second substrate, and a first alignment layer that is formed on the first substrate and is in contact with the liquid crystal layer. Here, the first alignment layer includes a first alignment base layer that is photoaligned, and a first alignment controlling layer that is extended from the inside of the first alignment base layer.