LCD Subpixel Switching Circuit for Charging Rate and Visibility
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Solution Overview
Problem
Conventional liquid crystal displays (LCDs) face challenges in improving visibility and charging rate, particularly in VA mode LCDs with divided pixels, where achieving optimal electric field intensity and uniform luminance across subpixels is difficult due to limitations in voltage application and switching device design.
Innovation Solution
The implementation of a liquid crystal display (LCD) design that includes first and second subpixels with specific switching devices and storage capacitors, allowing for different voltage levels to be applied across liquid crystal capacitors, thereby creating varying electric field intensities and improving charging rates through optimized voltage distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If one pixel is divided into two subpixels to improve lateral visibility, then visibility is improved, but the charging rate deteriorates due to increased complexity in voltage application and switching device design
Solution Approach 1:
The pixel is divided into two subpixels (first subpixel and second subpixel) with different voltage application mechanisms. The first subpixel uses a first switching device directly connected to the data line, while the second subpixel uses a second switching device connected through a third switching device and storage capacitor. This segmentation allows different charging paths and voltage levels for each subpixel, improving visibility while managing charging rate through differentiated design.
Solution Approach 2:
Different voltage levels are applied to different subpixels based on their specific needs. The first subpixel receives a first voltage level through the first switching device, while the second subpixel receives a second voltage level through the second, third, and fourth switching devices. This local quality approach allows optimization of visibility in each subpixel region while managing the overall charging rate of the pixel.
2Illumination intensity
If different voltage levels are applied to first and second subpixels to improve visibility, then luminance uniformity is improved, but device complexity increases due to additional switching devices and storage capacitors
Solution Approach 1:
The third switching device and storage capacitor serve multiple functions: they act as voltage level shifters between the data line and second subpixel, serve as charge storage elements to maintain voltage levels, and function as part of the addressing mechanism for the second subpixel. This multi-functionality reduces the need for completely separate control circuits for each subpixel, managing device complexity while achieving different luminance levels.
Solution Approach 2:
The third switching device and storage capacitor act as intermediary elements between the data line and the second subpixel. They mediate the voltage transfer by storing charge and providing controlled voltage levels to the second subpixel, enabling different luminance levels without requiring direct complex control from the data line for each subpixel.
3Productivity
If a fourth switching device is added to improve the charging rate of the second subpixel, then charging rate is improved, but kickback voltage increases
Solution Approach 1:
The storage capacitor is charged in advance through the third switching device before the fourth switching device is activated. This preliminary charging action stores the required voltage level, allowing the fourth switching device to quickly transfer charge to the second subpixel without generating excessive kickback voltage during the charging process.
Solution Approach 2:
The fourth switching device is controlled dynamically with a gate signal that is applied only during specific time periods when charging is needed. This dynamic control allows the fourth switching device to improve charging rate when necessary while remaining inactive during other periods, thereby limiting kickback voltage generation to minimal necessary levels.
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 enhances visibility by achieving different luminance levels across subpixels and improves the charging rate of the second subpixel, reducing kickback voltage and maintaining efficient display performance, especially in larger screen sizes.
Implementation Method 1
voltages are applied to field generating electrodes to generate an electric field in a liquid crystal layer
Implementation Method 2
the alignment of liquid crystal molecules of the liquid crystal layer is determined, and polarization of incident light is controlled
Implementation Method 3
the alignment of liquid crystal molecules of the liquid crystal layer is determined
Data Source
AI summary
A liquid crystal display includes a display panel including first and second subpixels, where the first subpixel includes a first switching device including a first electrode connected to the j-th data line, a second electrode connected to a first subpixel electrode and a gate electrode connected to an i-th gate line, the second subpixel includes a second switching device including a first electrode connected to a j-th data line, a second electrode connected to a second subpixel electrode and a gate electrode connected to the i-th gate line, a third switching device including a first electrode connected to the second subpixel electrode and a gate electrode connected to the i-th gate line, and a fourth switching device including a first electrode connected to the j-th data line, a second electrode connected to the first electrode of the third switching device and a gate electrode connected to the i-th gate line.