Zigzag Pixel Electrode Sub-Pixel Design for LCD Light Leakage
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Solution Overview
Problem
Patterned vertically aligned (PVA) LCDs experience decreased lateral visibility due to light leakage caused by the exposure of gate lines, which affect the liquid crystal alignment and generate electric fields, leading to uneven light transmission.
Innovation Solution
The implementation of a pixel electrode divided into sub-pixel electrodes driven by separate TFTs, with a zigzag design and connection electrodes that overlap gate lines to prevent electric field distortions and light leakage, ensuring uniform liquid crystal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gate line is disposed to cross a pixel, then the pixel can be driven by TFTs connected to the gate line, but the gate line becomes exposed through gaps and causes light leakage
Solution Approach 1:
The patent introduces connection electrodes as intermediary elements that bridge the gate line and the pixel electrode. These connection electrodes are positioned to overlap the gate line, acting as a mediator that blocks the electric field from the gate line from directly affecting the liquid crystal in the pixel region, thereby preventing light leakage while maintaining the gate line's crossing configuration for TFT operation
2Illumination intensity
If the pixel electrode is divided into sub-pixel electrodes driven by different TFTs, then lateral visibility is improved, but the device complexity increases due to additional gate lines and TFTs
Solution Approach 1:
The patent divides the pixel electrode into multiple sub-pixel electrodes (first sub-pixel electrode and second sub-pixel electrode), each driven by separate TFTs. This segmentation allows independent voltage control of different regions, enabling improved lateral visibility through differential driving while maintaining a manageable device structure by using the existing gate line configuration
3Extent of automation
If a gate-off voltage is applied to the gate line, then the TFT can be turned off, but the exposed gate line creates an electric field that misaligns liquid crystal molecules
Solution Approach 1:
The connection electrodes serve as a protective intermediary layer that overlaps the gate line. When gate-off voltage is applied to turn off the TFT, the connection electrodes block the resulting electric field from directly interacting with the liquid crystal molecules in the pixel region, preventing misalignment and maintaining stable liquid crystal composition while preserving TFT switching functionality
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 enhances lateral visibility by preventing light leakage and maintaining uniform liquid crystal alignment, improving the overall display quality by allowing independent voltage control of sub-pixel electrodes.
Implementation Method 1
The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer
Implementation Method 2
The applied electric field determines the orientations of LC molecules in the LC layer to adjust the polarization of incident light
Implementation Method 3
at least one of the connection electrodes overlaps the second gate line
Data Source
AI summary
A liquid crystal display (LCD) capable of preventing light leakage includes first and second gate lines which extend in a horizontal direction, a data line which is insulated from the first and second gate lines and crosses the first and second gate lines, first and second thin film transistors (TFTs) which are respectively connected to the first and second gate lines and are connected to the data line, and a pixel electrode which extends in zigzag fashion at an inclination to the first and second gate lines and is divided into a first area and a second area in a direction in which the pixel electrode extends. The pixel electrode includes a first sub-pixel electrode which is connected to the first TFT and has the first area and upper and lower portions of the second area, and a second sub-pixel electrode which is connected to the second TFT, has a middle portion of the second area, and has a lateral side adjoining a first portion of the first sub-pixel electrode, an upper side adjoining a lower side of an upper second portion of the first sub-pixel electrode, and a lower side adjoining an upper side of a lower second portion of the first sub-pixel electrode, the first and second areas being connected by a plurality of connection electrodes, and at least one of the connection electrodes overlapping the second gate line.