Alignment Film Manufacturing for LCD Flicker Reduction
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Solution Overview
Problem
Liquid crystal display devices employing optical alignment treatments for alignment films can exhibit display errors such as non-uniformity and flicker when driven at low frequencies, due to low-molecular components and ionic materials on the surface of the alignment film interacting with liquid crystals.
Innovation Solution
A method of manufacturing alignment films involves forming an organic layer, imparting alignment controllability with polarized ultraviolet rays, followed by oxidation, washing, and reduction steps to remove low-molecular components and unreacted monomers, resulting in a surface carbon concentration lower than inside the film, which suppresses flicker occurrence during low-frequency operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If optical alignment treatment is used to form alignment film, then alignment controllability is improved without static electricity and surface non-uniformity, but display errors such as non-uniformity and flicker occur during low-frequency operation
Solution Approach 1:
The patent extracts and removes harmful low-molecular components and ionic materials from the alignment film surface through oxidation treatment and washing steps. This extraction process eliminates the sources of display errors while preserving the beneficial alignment properties obtained through optical alignment treatment.
Solution Approach 2:
The patent changes the chemical composition parameters of the alignment film by introducing oxidation steps that modify the surface chemistry. This parameter change removes harmful substances and creates a cleaner surface that prevents flicker and non-uniformity during low-frequency operation.
2Stability of the object's composition
If optical alignment treatment is applied to organic layer, then uniaxial anisotropy is imparted for liquid crystal alignment, but low-molecular components remain on surface causing flicker during low-frequency drive
Solution Approach 1:
The patent converts the harmful low-molecular components generated during optical alignment into beneficial results by using oxidation treatment to selectively remove them. The washing step then eliminates these removed components, leaving a clean surface that maintains alignment functionality without flicker.
Solution Approach 2:
The oxidation treatment acts as an intermediary process between the optical alignment treatment and the final alignment film. It mediates by removing harmful low-molecular components while preserving the desired uniaxial anisotropy and alignment properties.
3Ease of manufacture
If alignment film contains ionic materials on surface, then alignment function is achieved, but ionic substances elute to liquid crystals causing display errors at low frequency
Solution Approach 1:
The patent extracts ionic materials from the alignment film surface through oxidation and washing steps. This extraction eliminates the elution source that causes display errors during low-frequency operation while maintaining the alignment film's manufacturing simplicity.
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
The method effectively reduces visible flickers in liquid crystal display devices when driven at low frequencies, improving display stability and reducing errors associated with low-molecular components and ionic substances elution.
Implementation Method 1
polarized ultraviolet rays in a band of, for example, 254 nm to 365 nm are irradiated onto an organic layer to cut the molecules of the organic layer
Implementation Method 2
the optical alignment treatment, polarized ultraviolet rays in a band of, for example, 254 nm to 365 nm are irradiated onto an organic layer to cut the molecules of the organic layer in a direction parallel to the polarization direction, and thus uniaxial anisotropy is imparted to the organic layer
Implementation Method 3
oxidating the organic layer irradiated with the polarized ultraviolet rays
Implementation Method 4
reducing the washed organic layer
Data Source
AI summary
According to one embodiment, a method of manufacturing an alignment film, includes forming an organic layer on a substrate, irradiating polarized ultraviolet rays onto the organic layer to impart an alignment controllability of liquid crystal molecules, oxidating the organic layer irradiated with the polarized ultraviolet rays, washing the oxidated organic layer and reducing the washed organic layer.