LCD Pixel Electrode Design for Kick-Back Voltage Reduction
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Solution Overview
Problem
In liquid crystal displays (LCDs), particularly in vertical alignment (VA) mode and transflective LCDs, the design of pixel electrodes is limited, leading to increased parasitic capacitance and kick-back voltage, which deteriorates display characteristics and increases costs due to the need for more gate lines and reduced data lines.
Innovation Solution
The implementation of a liquid crystal display design featuring a substrate with gate lines, data lines, common voltage lines, thin film transistors, and pixel electrodes arranged in a matrix shape, where common voltage lines include expansion electrodes overlapping pixel electrodes, and the use of storage electrodes and passivation layers to enhance voltage storage and reduce parasitic capacitance, along with a manufacturing method that forms these components to optimize electrical stability and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pixel electrodes are arranged in the transverse direction to reduce gate lines and data lines, then manufacturing cost is reduced, but parasitic capacitance between gate electrode and source electrode increases causing kick-back voltage and deteriorated display characteristics
Solution Approach 1:
The invention changes the arrangement dimension of pixel electrodes from transverse to vertical direction, and repositions the common voltage line from horizontal to vertical orientation. This dimensional change allows the common voltage line to overlap with the pixel electrode in the vertical dimension, creating a storage capacitor that compensates for kick-back voltage without requiring additional horizontal space that would increase parasitic capacitance between gate and source electrodes.
Solution Approach 2:
The common voltage line serves dual functions: it provides the common voltage to the liquid crystal layer and simultaneously acts as one electrode of the storage capacitor by overlapping with the pixel electrode. This multi-functionality eliminates the need for separate storage capacitor electrodes, reducing overall structure complexity and parasitic capacitance while maintaining cost-effectiveness.
2Ease of manufacture
If pixel electrodes are arranged in the transverse direction to reduce the number of gate lines and data lines, then manufacturing cost is reduced, but design flexibility for VA mode and transflective LCD is limited
Solution Approach 1:
The vertical arrangement of pixel electrodes combined with the vertically-oriented common voltage line creates a universal structure that can be applied to both VA mode and transflective LCD designs. The overlapping configuration between common voltage line and pixel electrode provides consistent functionality across different LCD types, enabling design flexibility without increasing manufacturing complexity.
3Area of moving object
If common voltage lines are formed in the same layer as data lines with expansion electrodes overlapping pixel electrodes, then aperture ratio is increased, but manufacturing precision requirements are increased
Solution Approach 1:
The invention merges the common voltage line formation with the data line formation process by placing both in the same conductive layer. The expansion electrode of the common voltage line is designed to overlap with the pixel electrode, and this overlapping region forms the storage capacitor. This merging approach increases aperture ratio by utilizing space that would otherwise be unused, while the systematic integration into the existing manufacturing process minimizes additional precision requirements.
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 improves display characteristics by reducing kick-back voltage, increasing aperture ratio, and allowing for cost-effective production with maintained resolution, while enabling flexible design for both VA mode and transflective LCDs.
Implementation Method 1
thin film transistors connected to the gate lines and the data lines
Implementation Method 2
a liquid crystal layer interposed between the two display panels. A voltage applied to the field generating electrodes generates an electric field on the liquid crystal layer, and the orientation of liquid crystal molecules of the liquid crystal layer is determined and the polarization of incident light is controlled through the generated electric field
Implementation Method 3
A voltage applied to the field generating electrodes generates an electric field on the liquid crystal layer
Implementation Method 4
common voltage lines include an expansion electrode overlapping at least a portion of the pixel electrode
Data Source
AI summary
A liquid crystal display includes a substrate, a plurality of gate lines formed on the substrate, a plurality of data lines intersecting the gate lines, a plurality of common voltage lines formed in the same layer as the data line and parallel to the data lines and transmitting a common voltage, a plurality of thin film transistors connected to the gate lines and the data lines, and a plurality of pixel electrodes respectively connected to the thin film transistors, arranged in a matrix shape, each of the plurality of pixels including a first edge parallel to the gate lines and a second edge having a shorter length than the first edge and neighboring the first edge.