Photoalignment Light Modulation Element for LCD Viewing Angle
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Solution Overview
Problem
Current liquid crystal display (LCD) technologies face challenges such as strong viewing-angle dependence of contrast, light leakage issues with crossed linear polarizers, and unfavorable processing steps like rubbing, which are not compatible with mass production, especially for flexible substrates and in-cell applications.
Innovation Solution
A light modulation element is developed using a pair of substrates with optical films like A-plates, C-plates, or biaxial films made from polymerizable LC materials, integrated with a photoalignment component and a liquid-crystalline medium, eliminating the need for a rubbing process and allowing in-cell optical film application, thereby reducing production costs and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rubbing process is used to align liquid crystals, then homogeneous alignment is achieved, but production complexity increases and flexibility is reduced
Solution Approach 1:
The patent replaces the mechanical rubbing process with a photoalignment method using UV irradiation. The alignment layer contains photoreactive compounds that reorient under UV light to create the desired liquid crystal alignment without physical contact or mechanical force, thereby eliminating the complexity of rubbing equipment and procedures while achieving homogeneous alignment.
Solution Approach 2:
The patent changes the alignment mechanism from mechanical (rubbing) to optical (UV irradiation). By controlling the wavelength, intensity, and duration of UV exposure, the alignment characteristics can be precisely tuned without the mechanical complexity of rubbing processes, simplifying production while maintaining alignment quality.
2Ease of manufacture
If optical films are integrated within the LCD cell, then production cost is reduced and image quality is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the optical film layer with the liquid crystal cell structure by integrating the optical compensation function directly into the cell's internal layers. This eliminates the need for separate optical films outside the cell, reducing overall production cost and simplifying the supply chain while maintaining the necessary optical compensation for viewing angle and light leakage control.
Solution Approach 2:
The integrated optical layer serves multiple functions simultaneously: it provides optical compensation for viewing angle dependence, controls light leakage in crossed polarizer configurations, and maintains structural integrity of the cell. This multi-functionality reduces the need for separate components, lowering production cost despite the increased complexity of the integrated structure.
3Device complexity
If photoalignment component is used instead of rubbing, then production process is simplified, but alignment stability may be affected
Solution Approach 1:
The patent uses photoalignment to replace mechanical rubbing, simplifying the production process. The photoreactive compounds in the alignment layer form stable molecular structures through UV-induced reactions that lock in the desired orientation, providing alignment stability comparable to or exceeding traditional rubbing methods without the mechanical complexity.
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 solution enhances viewing angle properties, reduces light leakage, and simplifies the production process by integrating optical films within the LCD cell, making it more robust and compatible with flexible substrates, while maintaining high temperature stability.
Implementation Method 1
a mechanism of orienting polymers comprising a suitable chromophore is described where photomodification is initiated by irradiation with linear polarised light resulting in a preferred molecular configuration
Implementation Method 2
one or more optical films selected from A-plates, C-plates, O-plates, biaxial films and/or cholesteric films
Implementation Method 3
an electrode structure capable of inducing an electric field substantially in parallel to the substrates main plane
Data Source
AI summary
The invention relates to a light modulation element comprising a pair of substrates, one or more optical films located on the inner side of one of the substrates, an electrode structure capable of inducing an electric field substantially in parallel to the substrates main plane, and a homogenously aligned liquid crystalline medium which is obtainable from a photoalignment component A) and a liquid-crystalline component B). Furthermore, the invention relates process of production of the light modulation element, to the use of the light modulation element in an electro optical device and to an electro optical device comprising said light modulation element.