LCD Alignment Layer Thickness Variation for Brightness Uniformity
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Solution Overview
Problem
Liquid crystal display (LCD) devices face issues with regional differences in brightness due to ionic impurities accumulating in specific areas, causing uneven pixel brightness.
Innovation Solution
The implementation of a design with dummy areas adjacent to the display area, where the alignment layer is thicker, and the use of dummy pixel electrodes and data lines connected to the outermost sides of the display area, helps in minimizing these differences by reducing the electric field intensity in these areas, thus reducing ionic impurity accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If dummy areas are added to the display panel to reduce ionic impurity accumulation, then regional brightness uniformity is improved, but device structure complexity increases
Solution Approach 1:
The display panel is segmented into a display area and dummy areas, with the dummy areas positioned at specific locations (e.g., left and right sides) to locally address ionic impurity accumulation problems without modifying the entire panel structure. This segmentation allows targeted intervention while preserving the overall simplicity of the display device.
Solution Approach 2:
Different regions of the display panel are assigned different functions: the display area for image output and the dummy areas for ionic impurity management. The dummy areas have different electrode configurations and electric field characteristics specifically tailored to reduce ion accumulation, while the display area maintains its original high-quality display properties.
2Object-generated harmful factors
If the alignment layer thickness is increased in dummy areas to reduce electric field intensity, then ionic impurity accumulation is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The alignment layer is configured with different thickness characteristics in different regions: a first thickness in the display area and a second thickness (greater than the first) in the dummy areas. This local differentiation allows the dummy areas to generate weaker electric fields that reduce ionic impurity accumulation, while the display area maintains its original performance characteristics.
Solution Approach 2:
The alignment layer thickness parameter is changed specifically in the dummy areas to alter the electric field intensity. By increasing the thickness in dummy areas, the electric field strength is reduced, which in turn reduces the accumulation of ionic impurities without affecting the display area's electric field characteristics.
3Stability of the object's composition
If dummy pixel electrodes and data lines are added to the dummy areas, then electric field distribution is improved, but device complexity increases
Solution Approach 1:
The electrode system is segmented into display pixel electrodes in the display area and dummy pixel electrodes in the dummy areas. Similarly, data lines are segmented into display data lines and dummy data lines. This segmentation allows independent optimization of electric field distribution in different regions while maintaining a modular structure that limits overall complexity increase.
Solution Approach 2:
The dummy pixel electrodes and dummy data lines serve multiple functions: they establish electric field distribution in the dummy areas, prevent ionic impurity accumulation, and maintain structural symmetry with the display area. This multi-functionality justifies the added components by providing benefits beyond simple electric field generation.
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 effectively minimizes regional brightness differences by weakening the electric field in dummy areas, reducing ionic impurity accumulation and enhancing the uniformity of pixel brightness across the LCD device.
Implementation Method 1
an alignment layer disposed on the pixel electrodes, where an average thickness of the alignment layer is larger in the first and second dummy areas than in the display area
Implementation Method 2
An LCD device applies an electric field to a liquid crystal layer interposed between two substrates, and displays a desired image by adjusting an intensity of the electric field so as to adjust an amount of light transmitted through the liquid crystal layer
Implementation Method 3
The ionic impurities may accumulate in a particular region of the LCD device, and as a result, pixels in the particular region may appear to be brighter than other pixels in the rest of the LCD device
Data Source
AI summary
A liquid crystal display device includes a substrate including a display area in which display pixels are arranged in a row direction and a column direction, a first dummy area, which is adjacent to a first side, in the row direction, of the display area, and a second dummy area, which is adjacent to a second side, in the row direction, of the display area, pixel electrodes on the substrate, the pixel electrodes including display pixel electrodes, which are respectively disposed in the display pixels, first dummy pixel electrodes, which are disposed in the first dummy area in the column direction, and second dummy pixel electrodes, which are disposed in the second dummy area in the column direction, and an alignment layer disposed on the pixel electrodes, where an average thickness of the alignment layer is larger in the first and second dummy areas than in the display area.