UV Absorbing Layer for LCD Alignment Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The pre-tilt angle of the alignment layer in liquid crystal displays can be altered by external fluorescent lights with UV wavelengths, leading to alignment instability and deterioration of display quality.
Innovation Solution
A light absorption layer is introduced between the substrates, specifically absorbing UV wavelengths between 280 nm and 450 nm, and an overcoat is formed to prevent external light from affecting the alignment stability, using a polymer layer combined with a light alignment monomer, such as an acrylate group or benzene derivative, to maintain consistent liquid crystal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the photo alignment layer is used to pre-tilt liquid crystals, then transmittance and response time are improved, but alignment stability deteriorates due to UV light from external fluorescent lights
Solution Approach 1:
A light absorption layer is introduced as an intermediary between the external environment and the photo alignment layer. This layer absorbs UV wavelengths (280-450 nm) from external fluorescent lights, preventing them from reaching and altering the photo alignment layer's pre-tilt angle, thus maintaining alignment stability while preserving the productivity benefits
Solution Approach 2:
The harmful UV light that causes alignment instability is converted into a beneficial filtering mechanism. The light absorption layer selectively absorbs harmful UV wavelengths while allowing visible light to pass through, thus protecting the photo alignment layer without compromising display performance or requiring changes to the photo-alignment process itself
2Ease of manufacture
If external fluorescent lights with UV wavelengths are present, then manufacturing process is simplified, but alignment stability deteriorates
Solution Approach 1:
The light absorption layer serves as a protective intermediary that allows the manufacturing process to remain simple (using conventional fluorescent lighting) while blocking the harmful UV wavelengths that would otherwise cause alignment instability. This maintains ease of manufacture without sacrificing reliability
3Device complexity
If no light absorption layer is used, then device structure is simpler, but alignment stability deteriorates under UV exposure
Solution Approach 1:
The light absorption layer is implemented as a thin film structure that adds minimal complexity to the device while providing effective UV protection. This thin film approach maintains relative structural simplicity while achieving the reliability improvement needed to prevent alignment instability under UV exposure
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 solution effectively prevents alignment spots and maintains alignment stability by absorbing specific UV wavelengths, thereby enhancing the durability and performance of liquid crystal displays.
Implementation Method 1
a light absorption layer disposed between the first substrate and the first alignment layer, or the second substrate and the second alignment layer, wherein the light absorption layer absorbs light having a UV wavelength of about 280 nm to about 450 nm
Implementation Method 2
The photo alignment method uses a polymer having an optical functional reactor such as azobenzene, cumarine, chalcone, and cinnamate, and an optical isomerization or a photo-crosslink may anisotropically take place by irradiating the polymers with the polarized light such that the polymer anisotropy is formed on the surface of the polymer layer, thereby aligning the liquid crystal in the predetermined direction
Data Source
AI summary
A liquid crystal display is presented. The liquid crystal display includes: a first substrate; a pixel electrode formed on the first substrate; a first alignment layer formed on the pixel electrode; a second substrate facing the first substrate; a common electrode formed on the second substrate; a second alignment layer formed on the common electrode; a liquid crystal layer formed between the first alignment layer and the second alignment layer; and a light absorption layer formed between the first substrate and the first alignment layer, or the second substrate and the second alignment layer, wherein the light absorption layer absorbs light having a UV wavelength between about 280 nm and about 450 nm.