Double-Layered Electrode Structure for IPS LCD Reflectance Reduction
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Solution Overview
Problem
In-plane switching (IPS) mode liquid crystal display (LCD) devices suffer from high ambient light reflectance, leading to rainbow stains and decreased ambient contrast ratio, which degrades image quality, and require complex manufacturing processes.
Innovation Solution
The IPS mode LCD device employs a double-layered structure for the pixel and common electrodes, with a lower layer of molybdenum-titanium alloy (MoTi) and an upper layer of transparent conductive materials like indium-tin-oxide (ITO) or copper nitride, and eliminates the black matrix by overlapping color filter patterns to reduce reflectance and simplify fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer electrode structure is used in IPS mode LCD, then the manufacturing process is simple, but the ambient light reflectance is high causing rainbow stains and poor image quality
Solution Approach 1:
The patent applies composite materials by forming a double-layered electrode structure consisting of a first electrode layer (e.g., ITO) and a second electrode layer (e.g., MoTi alloy). This composite structure reduces ambient light reflectance and eliminates rainbow stains while maintaining electrical functionality, resolving the contradiction between manufacturing simplicity and optical performance.
2Ease of manufacture
If a black matrix is used to prevent light leakage, then the aperture ratio is reduced, but the manufacturing process requires additional masks
Solution Approach 1:
The patent extracts and eliminates the black matrix component from the traditional LCD structure. By using the double-layered electrode structure with specific material combinations, the invention achieves light leakage prevention without requiring a separate black matrix layer, thereby reducing the number of mask processes and increasing aperture ratio.
Solution Approach 2:
The double-layered electrode structure serves multiple functions simultaneously: it provides electrical conductivity, reduces ambient light reflectance, prevents rainbow stains, and eliminates the need for a separate black matrix. This multi-functionality resolves the contradiction by combining what were previously separate components into a unified structure.
3Manufacturing precision
If the pixel and common electrodes are formed separately, then the manufacturing precision is maintained, but the overall device complexity increases
Solution Approach 1:
The patent merges the pixel electrode and common electrode into a unified double-layered electrode structure where the first and second electrode layers serve dual purposes. This combination maintains manufacturing precision through sequential formation processes while reducing device complexity by eliminating the need for separate electrode structures and associated alignment procedures.
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 configuration significantly reduces ambient light reflectance to less than 39%, prevents rainbow stains, and enhances ambient contrast ratio while simplifying the manufacturing process and reducing production costs.
Implementation Method 1
at least two of the red, green and blue color filter patterns overlap each other at a boundary of the pixel regions
Implementation Method 2
liquid crystal molecules 11b between the common electrode 17 and the pixel electrode 30 are horizontally arranged due to the horizontal electric field 'L'
Data Source
AI summary
An IPS mode LCD device includes gate and data lines on a first substrate and crossing to define pixel regions; a thin film transistor connected to the gate lines and the data lines; a first common electrode and a pixel electrode on the first substrate and alternating with each other in each pixel region, each of the first common electrode and the pixel electrode including lower and upper layers; a color filter layer including red, green and blue color filter patterns and on a second substrate, the color filter patterns corresponding to each pixel region; and a liquid crystal layer between the first and second substrates, wherein at least two of the color filter patterns overlap at a boundary of the pixel regions, and wherein the lower layer is made of MoTi, and the upper layer is made of a transparent conductive material or copper nitride.