Common Electrode Layout for Low-Refresh LCD Flicker Reduction
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Solution Overview
Problem
Liquid crystal display devices with low refresh rates experience flicker issues due to significant changes in pixel transmittance, leading to reduced display quality, increased power consumption, and light leakage, while also facing challenges with parasitic capacitance and aperture ratio.
Innovation Solution
A display device design featuring a common electrode with distinct overlapping regions intersecting at specific angles with signal and pixel electrodes, reducing alignment interference and maintaining transmittance stability, combined with a transistor structure using In-Ga-Zn oxide films for improved electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the refresh rate is lowered to reduce power consumption, then power consumption is reduced, but pixel transmittance changes significantly causing flicker and reduced display quality
Solution Approach 1:
The common electrode is divided into multiple regions with different extending directions: a first region overlapping with the signal line and a second region overlapping with the pixel electrode. This segmentation allows different regions to serve different functions - the first region minimizes parasitic capacitance effects while the second region maintains proper liquid crystal alignment, thereby reducing flicker at low refresh rates
Solution Approach 2:
Different regions of the common electrode are given different orientations tailored to their local requirements. The first region's extending direction is optimized for minimizing interference with signal lines, while the second region's extending direction is optimized for maintaining liquid crystal alignment in the pixel electrode area, achieving local optimization of display quality
2Device complexity
If the common electrode extends parallel to the signal line to reduce parasitic capacitance, then wiring delay is reduced, but liquid crystal alignment is interfered with causing display defects
Solution Approach 1:
The common electrode is segmented into distinct regions with different orientations. The first region overlapping with the signal line can be oriented to minimize parasitic capacitance, while the second region overlapping with the pixel electrode is oriented to maintain proper liquid crystal alignment, thus resolving the conflict between wiring delay and alignment quality
Solution Approach 2:
The extending direction of the common electrode is locally optimized in different regions. In the first region near the signal line, the orientation minimizes electrical interference, while in the second region near the pixel electrode, the orientation ensures proper liquid crystal alignment, achieving local quality optimization for each functional requirement
3Illumination intensity
If the aperture ratio is increased to improve display brightness, then light transmission is improved, but parasitic capacitance increases causing wiring delay
Solution Approach 1:
The common electrode is designed with an asymmetric configuration where the first region overlapping with the signal line has a different extending direction than the second region overlapping with the pixel electrode. This asymmetric design allows the electrode to maintain high aperture ratio for brightness while minimizing the overlapping area with signal lines to reduce parasitic capacitance
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 reduces flicker, enhances display quality, minimizes power consumption, and increases aperture ratio, while maintaining a high viewing angle and reduced parasitic capacitance, thus improving overall display performance.
Implementation Method 1
alignment of liquid crystal molecules is controlled by applying an electric field generated between the pixel electrode and a common electrode to the liquid crystal in the opening
Implementation Method 2
a transistor structure using In-Ga-Zn oxide films for improved electrical characteristics
Data Source
AI summary
To provide a display device with excellent display quality, in a display device including a signal line, a scan line, a transistor, a pixel electrode, and a common electrode in a pixel, the common electrode is included in which an extending direction of a region overlapping with the signal line differs from an extending direction of a region overlapping with the pixel electrode in a planar shape and the extending directions intersect with each other between the signal line and the pixel electrode. Thus, a change in transmittance of the pixel can be suppressed; accordingly, flickers can be reduced.