Liquid Crystal Display Subpixel Voltage Control for Side Visibility
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Solution Overview
Problem
Vertically aligned mode liquid crystal displays face challenges in accurately expressing grayscale levels in low gray regions and maintaining luminance when side visibility is improved, leading to impaired driving efficiency.
Innovation Solution
A liquid crystal display design that divides a pixel into subpixels with different voltage applications, using a reference voltage line connected to a boosting capacitor to control the voltage of one subpixel electrode higher than the data voltage, ensuring smooth grayscale changes and improved side visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If one pixel is divided into two subpixels with different voltages to improve side visibility, then side visibility is improved, but grayscale levels in low gray region cannot be accurately expressed and luminance is lowered
Solution Approach 1:
The pixel electrode is divided into first and second subpixel electrodes, allowing independent voltage control of each subpixel. This segmentation enables different voltage applications (data voltage to first subpixel, data voltage plus reference voltage to second subpixel) to achieve both improved side visibility through voltage differentiation and accurate grayscale expression through controlled voltage differences.
Solution Approach 2:
A reference voltage line and reference voltage are introduced as intermediary elements to adjust the voltage of the second subpixel electrode. The reference voltage acts as a mediator that, when added to the data voltage, creates the appropriate voltage difference between subpixels to improve side visibility while maintaining accurate grayscale control through the boosting capacitor's regulation.
2Illumination intensity
If one pixel is divided into two subpixels with different voltages to improve side visibility, then side visibility is improved, but overall luminance is lowered and driving efficiency is impaired
Solution Approach 1:
The voltage parameters of the subpixel electrodes are precisely controlled through the reference voltage addition and boosting capacitor mechanism. By adjusting the reference voltage magnitude and timing, the system achieves optimal voltage differentiation for side visibility improvement while preventing excessive voltage differences that would reduce overall luminance and impair driving efficiency.
Solution Approach 2:
The reference voltage is applied in advance through the third switching element and boosting capacitor to the second subpixel electrode before the main data voltage is fully established. This preliminary voltage preparation ensures that when both subpixels are fully driven, they maintain appropriate voltage relationships for improved side visibility without compromising overall luminance or driving efficiency.
3Illumination intensity
If voltage of one subpixel is lowered to create voltage difference, then side visibility is improved, but luminance of side is increased and grayscale accuracy is reduced
Solution Approach 1:
Instead of lowering the voltage of one subpixel as in conventional approaches, this invention raises the voltage of the second subpixel by adding the reference voltage to the data voltage. This inverted approach achieves the necessary voltage difference for improved side visibility while preventing the luminance increase and grayscale accuracy loss that occur when voltages are reduced.
Solution Approach 2:
The conventional mechanical/electrical approach of voltage reduction is replaced with a voltage addition mechanism using the reference voltage line and boosting capacitor. This substitution allows precise control of voltage differences through electrical field manipulation, achieving side visibility improvement without the adverse effects of voltage lowering on grayscale accuracy.
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 effectively expresses grayscale levels in low gray regions, maintains high luminance, and enhances side visibility to be comparable to front visibility, thereby improving overall visibility and driving efficiency.
Implementation Method 1
The liquid crystal display generates an electric field in the liquid crystal layer by applying voltage to the field generating electrodes
Implementation Method 2
the direction of liquid crystal molecules of the liquid crystal layer is determined by the generated electric field, thus controlling polarization of incident light
Implementation Method 3
a vertically aligned mode liquid crystal display, in which longitudinal axes of liquid crystal molecules are arranged substantially vertical to the display panel
Data Source
AI summary
A liquid crystal display includes a first substrate, a first gate line disposed on the first substrate, a second gate line disposed on the first substrate, a data line disposed on the first substrate, a reference voltage line disposed on the first substrate and extending substantially to be parallel to the data line, a first subpixel electrode disposed in a pixel area on the first substrate, a second subpixel electrode disposed in the pixel area on the first substrate, a first switching element connected to the first gate line, the data line and the first subpixel electrode, a second switching element connected to the first gate line, the data line and the second subpixel electrode, and a third switching element connected to the first subpixel electrode and the reference voltage line.