LCD Sub-pixel Voltage Boosting for Lateral Visibility
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Solution Overview
Problem
Vertical alignment (VA) mode LCDs suffer from poor lateral visibility compared to frontal visibility, and existing methods to improve this, such as dividing pixels into sub-pixels with different voltages, degrade the aperture ratio and reduce light transmittance.
Innovation Solution
The implementation of a configuration where each pixel has two sub-pixel electrodes with different charge voltages, one boosted and one dropped, using voltage-boosting and voltage-dropping capacitors, respectively, to maintain the same data voltage while adjusting the charge voltages, thereby enhancing lateral visibility and light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If each pixel is divided into two sub-pixels with different voltages applied (one directly supplied, one subjected to voltage drop by capacitive coupling), then lateral visibility is improved, but aperture ratio is degraded and light transmittance is decreased
Solution Approach 1:
The patent applies different voltage conditions to different sub-pixels within the same pixel region. Specifically, first sub-pixels receive a first voltage while second sub-pixels receive a second voltage that is lower than the first voltage. This local differentiation of voltage quality enables improved lateral visibility through gamma curve distortion prevention while maintaining adequate aperture ratio by not requiring additional capacitive coupling structures that would reduce the active display area.
Solution Approach 2:
The pixel array is segmented into first sub-pixels and second sub-pixels that are driven by different voltage signals. This segmentation allows independent voltage control for each sub-pixel type, enabling the display to achieve both improved lateral visibility and maintained aperture ratio by optimizing the voltage distribution across different sub-pixel groups without requiring overlapping capacitive structures.
2Illumination intensity
If each pixel is divided into two sub-pixels with different voltages applied, then lateral visibility is improved, but light transmittance is decreased due to reduction in average voltage
Solution Approach 1:
The patent changes the voltage parameter distribution across sub-pixels to improve lateral visibility while maintaining light transmittance. By applying a higher first voltage to first sub-pixels and a lower second voltage to second sub-pixels, the system achieves gamma curve optimization for lateral viewing without significantly reducing the average voltage across the entire pixel array, thereby preserving light transmittance performance.
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 improves lateral visibility by preventing distortion in the gamma curve and increases light transmittance by allowing a higher voltage difference between sub-pixel electrodes, even with a small capacitance, thus maintaining an improved aspect ratio and enhanced display performance.
Implementation Method 1
each pixel has two sub-pixel electrodes with different charge voltages, one boosted and one dropped, using voltage-boosting and voltage-dropping capacitors, respectively
Implementation Method 2
LCDs control the transmittance of light incident on the panels by the application of selected voltages to the field-generating electrodes so as to generate electric fields, which determine the orientation of the liquid crystal molecules in the liquid crystal layer and thereby adjust the polarization of the light incident upon the panel
Data Source
AI summary
An LCD having an enhanced light transmittance and improved lateral visibility includes gate and storage electrode lines formed on a first insulating substrate, a data line insulated from and crossing the gate line, a first source electrode partially overlapping an nth gate line and connected to the data line, first and second drain electrodes partially overlapping the nth gate line and separated from the first source electrode, a first sub-pixel electrode electrically connected to a first drain electrode, a second sub-pixel electrode electrically connected to a second drain electrode, a second source electrode partially overlapping an (n+1)th gate line and electrically connected to the second sub-pixel electrode, and a third drain electrode partially overlapping the (n+1)th gate line and separated from the second source electrode and operable to boost a charge voltage of the first sub-pixel electrode and to drop a charge voltage of the second sub-pixel electrode.