FFS LCD Common Electrode Layout Without Aperture-Loss Wiring
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Solution Overview
Problem
Conventional liquid crystal display devices face issues with reduced contrast and aperture ratio due to insufficient common electric potential supply, particularly in larger panels, where the common electrode's high sheet resistivity and internal wiring cause light-shielding and voltage degradation.
Innovation Solution
A liquid crystal display device design where the common electrode extends over all pixels and is connected to a peripheral common electric potential line on the periphery of the display region, eliminating the need for auxiliary common electrode lines and ensuring sufficient common electric potential supply through low resistance paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary common electrode lines are provided within the display region to supply common electric potential, then the common electrode can be provided with sufficient common electric potential, but the aperture ratio is reduced due to light shielding by these lines
Solution Approach 1:
The invention extracts and removes the auxiliary common electrode lines from the display region. Instead of providing common electric potential through lines within the display area, the common electrode is extended to the periphery of the display region where it can be connected to the common potential source without obstructing the display area, thus eliminating the light shielding problem while maintaining sufficient common electric potential supply.
Solution Approach 2:
The invention transitions the connection approach from a two-dimensional planar connection within the display region to a peripheral connection at the boundary of the display region. By extending the common electrode to the periphery and connecting it there, the solution moves the connection path to another spatial dimension (the periphery), avoiding interference with the display area while maintaining electrical connectivity.
2Area of stationary object
If the panel size is increased to achieve larger display area, then the display area is expanded, but the common electric potential supply becomes insufficient leading to reduced display quality
Solution Approach 1:
For larger panels, the invention extends the common electrode to the periphery of the display region, creating a longer electrical path from the common potential source to all areas of the common electrode. This peripheral connection approach provides a more effective electrical pathway that maintains sufficient common electric potential supply across large display areas, overcoming the limitation of insufficient potential supply in larger panels.
3Illumination intensity
If transparent electrode material is used for common electrode to maintain transparency, then the display transparency is preserved, but the electrical resistance increases reducing common electric potential supply efficiency
Solution Approach 1:
The invention segments the common electrode structure by extending it to the periphery of the display region and connecting it there. This segmentation allows the transparent electrode material to be used effectively within the display area for transparency, while the peripheral connection provides an optimized electrical pathway that compensates for the higher resistance of transparent materials, ensuring sufficient common electric potential supply.
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 design improves the aperture ratio and ensures a bright display by securely providing common electric potential to the common electrode, reducing light-shielding and voltage-related degradations, thereby enhancing display quality.
Implementation Method 1
an alignment direction of liquid crystal molecules is controlled by a lateral electric field generated between a pixel electrode and a common electrode
Implementation Method 2
rotating the liquid crystal molecules in a plane parallel to a substrate with a lateral electric field generated between the electrodes on the same substrate
Data Source
AI summary
A liquid crystal display device according to FFS technology is provided, which sufficiently provides a common electrode with common electric potential and improves an aperture ratio of pixels. A pixel electrode is formed of a first layer transparent electrode. A common electrode made of a second layer transparent electrode is formed above the pixel electrode interposing an insulation film between them. The common electrode in an upper layer is provided with a plurality of slits. The common electrode extends over all the pixels in a display region. An end of the common electrode is disposed on a periphery of the display region and connected with a peripheral common electric potential line that provides a common electric potential Vcom. There is provided neither an auxiliary common electrode line nor a pad electrode, both of which are provided in a liquid crystal display device according to a conventional art.