Subpixel Electrode Driving for LCD Viewing Angle
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Solution Overview
Problem
Liquid crystal display devices, particularly MVA type, suffer from image washout when viewed from oblique angles due to uneven luminance characteristics, leading to suboptimal grayscale representation and reduced image quality.
Innovation Solution
The implementation of a liquid crystal display device with a data bus driving circuit that applies distinct driving signals to first and second subpixel electrodes, and optionally utilizes slits between subpixel electrodes with opposite polarities to enhance alignment regulation, thereby improving viewing angle characteristics and reducing aperture ratio losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a liquid crystal display device uses MVA type with vertical alignment to achieve broad viewing angles, then viewing angle characteristics are improved, but image washout occurs when viewed from oblique angles due to uneven luminance characteristics
Solution Approach 1:
Each pixel is divided into a first subpixel electrode and a second subpixel electrode, allowing independent control of luminance for each subpixel. This segmentation enables differential driving signals to be applied, correcting the luminance unevenness that causes image washout when viewed from oblique angles, while maintaining the broad viewing angle characteristics of MVA type display
Solution Approach 2:
Different driving signals are applied to the first and second subpixel electrodes based on their specific positions and luminance characteristics. The data bus driving circuit adjusts the driving signals locally for each subpixel to compensate for the uneven luminance distribution, thereby suppressing image washout while preserving the overall viewing angle advantages
2Adaptability or versatility
If subpixel electrodes are divided to suppress image washout, then viewing angle characteristics improve, but aperture ratio is reduced due to light-blocking films needed between subpixel electrodes
Solution Approach 1:
The light-blocking function is extracted from the gap regions between subpixel electrodes by providing light-blocking films only in the non-display regions. This allows the subpixel electrodes to be closely arranged without requiring light-blocking structures between them, thereby maintaining high aperture ratio while still achieving the differential driving needed to suppress image washout
Solution Approach 2:
The light-blocking function is moved from the planar gap regions between subpixels to the vertical dimension by positioning light-blocking films in non-display regions. This dimensional repositioning allows subpixel electrodes to occupy more area without compromising the light-blocking function, thus improving aperture ratio while maintaining viewing angle characteristics
3Manufacturing precision
If halftone technologies with capacitive coupling are used to suppress grayscale inversion, then grayscale representation improves, but applied voltage must be too high and structures become complicated
Solution Approach 1:
Instead of using complex capacitive coupling structures that require additional electrodes and high voltages, the invention uses a simpler driving approach where the data bus driving circuit directly controls the luminance of each subpixel electrode through adjusted driving signals. This simpler method achieves the same grayscale correction function without the complexity and high voltage requirements of capacitive coupling structures
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 effectively suppresses image washout when viewed from oblique directions, enhances image quality by maintaining optimal grayscale representation across various angles, and improves the aperture ratio by allowing narrower slit widths.
Implementation Method 1
liquid crystal molecules in the liquid crystal layer are aligned substantially perpendicularly in a state in which no voltage is applied
Implementation Method 2
a data bus driving circuit, which supplies a driving signal to the data bus lines to apply the driving signal to the subpixel electrodes
Implementation Method 3
alignment regulation structure, which regulates the direction of alignment of the liquid crystal molecules provided between the substrates in a plurality of directions
Data Source
AI summary
A liquid crystal display device, in which the liquid crystal molecules are aligned vertically when no voltage is applied, includes pixels each having plural sub-pixel electrodes, a data bus drive circuit for applying drive signals to the sub-pixel electrodes via a data bus line and a switching element, and alignment regulation structure for regulating the direction of alignment of liquid crystal molecules. The first and second sub-pixel electrodes have different areas. The data bus drive circuit applies a first drive signal, which causes luminance to change from minimum to maximum for an increase of input grayscale of image signal, to the first sub-pixel electrode, and a second drive signal, which causes the luminance to be lower than the first drive signal, to the second sub-pixel electrode.