LCD Pixel Electrode Width Variation for Gray Level Accuracy
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Solution Overview
Problem
Liquid crystal displays (LCDs) face challenges in accurately expressing gray levels in low gray regions, leading to increased lateral luminance, reduced luminance efficiency, and brightness differences between adjacent pixels due to variations in pixel voltage and aperture ratios.
Innovation Solution
The LCD design includes a first and second reference voltage line with different polarities, overlapping and non-overlapping configurations with pixel electrodes, and varying widths to maintain consistent pixel voltage and aperture ratios, ensuring accurate gray expression and uniform brightness across the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If one pixel is divided into two subpixels with different transmittance by applying different voltages, then lateral visibility is improved, but luminance accuracy in low gray region deteriorates
Solution Approach 1:
The patent applies different voltage strategies to different subpixels within the same pixel. Specifically, one subpixel receives a first voltage while another subpixel receives a second voltage that is lower than the first voltage by a predetermined value. This local differentiation allows each subpixel to contribute differently to overall luminance, improving lateral visibility while maintaining gray accuracy through compensated voltage control.
2Illumination intensity
If voltage of one subpixel is lowered to improve lateral visibility, then lateral luminance is increased, but driving efficiency deteriorates
Solution Approach 1:
The patent systematically adjusts voltage parameters across different subpixels and gray levels. By setting the second voltage to be lower than the first voltage by a predetermined value, the system optimizes the balance between lateral luminance enhancement and energy consumption. This parameter optimization ensures that the lower voltage subpixel contributes sufficient lateral luminance without causing excessive energy loss, thereby maintaining acceptable driving efficiency.
3Measurement precision
If signal wire area overlap with pixel electrode is changed to adjust pixel voltage, then pixel voltage control is improved, but aperture ratio variation occurs
Solution Approach 1:
The patent segments the pixel structure into distinct subpixels with separate voltage control mechanisms. Instead of adjusting the overall pixel electrode area, the invention divides the pixel into multiple subpixels that can be independently controlled. This segmentation allows precise pixel voltage control through differential voltage application to subpixels without requiring changes to the overall aperture ratio, thereby avoiding brightness differences between adjacent pixels.
4Measurement precision
If aperture ratios of adjacent pixels are different, then pixel voltage can be adjusted, but brightness difference between adjacent pixels occurs
Solution Approach 1:
The patent implements equipotential control by applying voltages to subpixels such that the overall pixel maintains a consistent effective aperture ratio across the display. By carefully controlling the voltage distribution among subpixels, the system ensures that adjacent pixels exhibit similar luminance characteristics despite internal subpixel voltage differences. This approach prevents brightness differences between adjacent pixels while maintaining the necessary voltage adjustability for gray level control.
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 allows for precise gray level representation in low gray regions, maintains luminance efficiency, and prevents brightness differences between adjacent pixels by stabilizing pixel voltage and aperture ratios.
Implementation Method 1
a vertically aligned mode LCD, in which liquid crystal molecules are aligned so that long axes of the liquid crystal molecules are perpendicular to the upper and lower panels
Implementation Method 2
applying voltages to the field-generating electrodes to generate an electric field in the LC layer that determines the orientations of LC molecules therein to adjust polarization of incident light thereto
Data Source
AI summary
A liquid crystal display includes a first substrate including pixels, a gate line disposed on the first substrate, data lines disposed on the first substrate, a first reference voltage line and a second reference voltage line respectively disposed on the first substrate and applying a first reference voltage and a second reference voltage having different polarities from each other, a pixel electrode disposed in one pixel area and including a first subpixel electrode and a second subpixel electrode, where a first pixel column may overlap the first reference voltage line and the second reference voltage line, a second pixel column adjacent to the first pixel column may not overlap the first reference voltage line and the second reference voltage line, and a first width of the pixel electrode of the first pixel column may be different from a second width of the pixel electrode of the second pixel column.