LCD Pixel Electrode Quadrant Design for Side Visibility
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Solution Overview
Problem
Vertically aligned liquid-crystal display (LCD) devices suffer from poor side visibility, especially when displaying low gray scale images, with images appearing brighter at the sides than at the front, leading to deteriorated visibility as the brightness difference increases.
Innovation Solution
A pixel electrode structure is introduced, featuring a stem electrode dividing the pixel region into quadrants with branch electrodes and in-between electrodes, where the branch electrodes are extended in different directions and the spacing and widths of these electrodes vary to control liquid crystal orientation and improve visibility without compromising transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single pixel is divided into two sub-pixels with different voltage applied to improve visibility, then visibility is improved, but additional opaque elements are required and transmittance deteriorates
Solution Approach 1:
The pixel electrode is segmented into multiple domains (first to fourth domains) with different liquid crystal orientations, allowing each domain to contribute to visibility from different viewing angles while maintaining overall pixel transparency without requiring additional opaque elements
Solution Approach 2:
Different regions of the pixel electrode are designed with different properties (different liquid crystal orientations in different domains) to optimize visibility from various viewing angles, while the entire structure remains transparent to maintain high transmittance
2Adaptability or versatility
If cut portions such as fine slits are defined in the field generating electrodes to form multiple domains, then multiple domains are formed, but the structure becomes more complex and transmittance is reduced
Solution Approach 1:
Instead of using cut portions in the planar direction, the patent uses vertical protrusions that extend from the lower substrate toward the upper substrate to define multiple domains, utilizing the third dimension to achieve domain formation without blocking light in the optical path
3Adaptability or versatility
If protrusions are formed on the field generating electrodes to form multiple domains, then multiple domains are formed, but the device structure becomes more complex
Solution Approach 1:
The protrusions serve multiple functions: they define multiple liquid crystal domains, generate the necessary electric fields for domain formation, and maintain structural simplicity by being integrated into the existing electrode architecture rather than adding separate components
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
The proposed pixel electrode structure enhances visibility by accurately controlling liquid crystal tilt directions, reducing transmittance differences across the display, thereby improving image clarity and brightness uniformity, especially at low gray scales.
Implementation Method 1
voltage is applied to field generating electrodes to generate electric field across a liquid-crystal layer, and liquid-crystal molecules in the liquid-crystal layer are aligned by the electric field so as to control the polarization of incident light
Implementation Method 2
liquid-crystal molecules in the liquid-crystal layer are aligned by the electric field so as to control the polarization of incident light
Implementation Method 3
liquid-crystal molecules in the liquid-crystal layer are aligned by the electric field so as to control the polarization of incident light
Data Source
AI summary
A liquid-crystal display device includes a first substrate and a second substrate including pixels, a liquid-crystal layer interposed between the first and second substrates, pixel electrodes disposed on the first substrate, each of the pixel electrodes disposed in a pixel region of the respective pixels, and a common electrode overlapping the pixel electrodes, where each of the pixel electrodes includes, a stem electrode extended in a first direction and in a second direction intersecting the first direction to divide the pixel region into quadrants, the quadrants corresponding to first to fourth domains, respectively, first branch electrodes, second branch electrodes, third branch electrodes, a first in-between electrode, and a second in-between electrode, and where widths of the first to third branch electrodes are equal to one another, and widths of the first and second in-between electrodes increase as farther from the stem electrode.