COT LCD Light Blocking via Pigment Lamination
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Solution Overview
Problem
Liquid crystal display devices with a color filter on TFT (COT) structure face challenges in improving picture quality and luminance due to the presence of a black matrix, which reduces aperture ratio, leading to lower luminance and limited resolution.
Innovation Solution
A method of fabricating a liquid crystal display device with a COT structure where color filters and thin film transistors are formed on an array substrate, eliminating the need for a black matrix by using a light blocking pattern made of opaque conductive material and laminating color pigments for light blocking layers, resulting in a triple-layer structure with low reflection and transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a black matrix is used to block light between pixels, then light leakage is prevented, but aperture ratio is reduced leading to lower luminance
Solution Approach 1:
The patent removes the traditional black matrix structure from the display device. Instead of using a separate black matrix layer, the light blocking function is integrated into the pixel electrode structure through transparent conductive materials and liquid crystal alignment, extracting the harmful black matrix element while maintaining its light blocking function through alternative means.
Solution Approach 2:
The patent changes the optical parameters of the pixel electrode region by using transparent conductive materials with specific transparency and conductivity characteristics. The liquid crystal alignment parameters are also modified to achieve proper light control without requiring opaque black matrix materials, thereby increasing the aperture ratio while maintaining light leakage prevention.
2Manufacturing precision
If a black matrix is used to define pixel boundaries, then pixel separation is achieved, but aperture ratio is reduced limiting resolution
Solution Approach 1:
The patent extracts and removes the black matrix component from the conventional LCD structure. Pixel separation is achieved through the pixel electrode pattern and liquid crystal alignment rather than through a separate black matrix layer, eliminating the need for this component while maintaining pixel boundary definition.
Solution Approach 2:
The pixel electrode structure is given multiple functions: it serves as both the electrical conductor for applying voltage to the liquid crystal and as the boundary definition element that separates pixels optically. This multi-functional design eliminates the need for a separate black matrix, increasing aperture ratio while maintaining pixel separation.
3Ease of manufacture
If color filters are formed on a separate color filter substrate, then color display is achieved, but attachment margin increases reducing aperture ratio
Solution Approach 1:
The patent merges the color filter formation process with the pixel electrode formation process on the same substrate. The pixel electrode regions inherently define the color filter locations, and both are formed simultaneously or in sequence without requiring a separate color filter substrate, thereby eliminating the attachment margin and increasing aperture ratio.
Solution Approach 2:
The array substrate serves multiple functions: it supports the thin film transistor circuitry, forms the pixel electrodes for electrical control, and defines the locations for color filters. This multi-functional substrate design eliminates the need for a separate color filter substrate, reducing attachment margins and increasing the effective display area.
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 approach enhances picture quality and luminance by minimizing reflectance and maximizing transmittance, thereby improving the overall performance and competitiveness of display products.
Implementation Method 1
forming a light blocking layer at the upper and lower boundaries of the pixel regions by laminating color pigments for the red, green, and blue color filters
Implementation Method 2
liquid crystal in the liquid crystal layer rotates due to a dielectric anisotropy according to the electric field formed between the common electrode and the pixel electrode
Data Source
AI summary
A liquid crystal display device having a color filter on TFT (COT) structure for high picture quality, high performance display and a method of fabricating the same are provided to reduce the luminance difference between a pixel portion and an outer portion by laminating color pigments in black matrix regions, forming a light blocking pattern to use as a black matrix, and configuring the light blocking pattern to have three layers to achieve black luminance.