Multi-Domain Vertical Alignment Pixel Structure for LCD
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Solution Overview
Problem
Multi-domain vertical alignment liquid crystal display panels face challenges with high fabricating costs due to complex driving designs and the occurrence of dark fringes, which reduce light transmittance and display quality, primarily because of alignment errors and limitations in pixel electrode width caused by process resolution and etching capabilities.
Innovation Solution
A substrate with a multi-domain vertical alignment pixel structure is designed, featuring a voltage drop layer and patterned pixel electrodes that are equipotential, with a voltage drop layer making the first electrical field smaller than the second, and a slit configuration that stabilizes liquid crystal molecule inclining directions, reducing the number of active devices and dark fringes while maintaining low color shift and high light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If slits are disposed on pixel electrodes to form bent electrical fields for wide viewing angle, then liquid crystal molecules incline towards different directions achieving wide viewing angle, but alignment error between upper and lower slits generates alignment region unevenness and reduces light transmittance
Solution Approach 1:
The patent transitions from a two-dimensional planar electrode structure to a three-dimensional protruding electrode structure. The pixel electrodes extend vertically from the substrate surface, creating multiple alignment regions at different heights. This dimensional change allows the formation of bent electrical fields without requiring precise horizontal alignment between separate slits, as each protruding electrode independently creates its own alignment region.
Solution Approach 2:
The patent divides the pixel electrode into multiple protruding segments that extend vertically from the substrate. Each protruding electrode segment creates a distinct alignment region for liquid crystal molecules. This segmentation allows independent control of electrical fields in different vertical zones, achieving wide viewing angle without requiring precise alignment between separate components.
2Manufacturing precision
If protection layer is added between pixel electrodes to solve alignment error, then alignment error problem is solved, but structure with slit generates dark fringe and reduces light transmittance
Solution Approach 1:
The patent converts the harmful effect of slits (which cause dark fringes) into a beneficial protruding electrode structure. Instead of using slits that create dark fringes by blocking light, the invention uses vertically extending electrodes that generate bent electrical fields to control liquid crystal alignment. This transforms the alignment error problem into an opportunity to create multiple vertical alignment regions that improve both alignment precision and light transmittance simultaneously.
3Illumination intensity
If two thin-film transistors are used to drive two layers of pixel electrodes, then low color shift is achieved, but driving design becomes complicated and fabricating cost increases
Solution Approach 1:
The patent makes a single thin-film transistor serve multiple functions by connecting it to multiple protruding pixel electrodes through contact holes. One TFT drives multiple electrode segments that create different alignment regions, replacing the need for separate TFTs for each electrode layer. This multi-functionality approach maintains color uniformity while simplifying the driving design and reducing fabricating cost.
Solution Approach 2:
The patent merges multiple pixel electrode layers into a single integrated protruding electrode structure that is driven by one TFT. Instead of using separate TFTs for each electrode layer, the invention combines the electrode functions into vertical protrusions from a single substrate layer, reducing device complexity while maintaining the ability to create multiple alignment regions for color uniformity.
4Illumination intensity
If pixel electrode width is increased to reduce dark fringe, then light transmittance improves, but process resolution and etching capability limitations prevent effective width increase
Solution Approach 1:
The patent resolves the width limitation by transitioning from a two-dimensional planar electrode to a three-dimensional protruding structure. Instead of increasing the horizontal width of the electrode (which is constrained by process resolution), the invention extends the electrode vertically from the substrate surface. This dimensional change allows the electrode to cover a larger effective area and reduce dark fringes without being limited by horizontal etching capabilities.
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 solution results in a cost-effective, simple structure with reduced dark fringes and improved light transmittance, achieving a low color shift effect and good display quality, while overcoming the limitations of existing technologies in terms of process width and etching capabilities.
Implementation Method 1
the first patterned pixel electrode provides a first electrical field to the liquid crystal layer, and the second patterned pixel electrode provides a second electrical field to the liquid crystal layer. The voltage drop layer makes the first electrical field smaller than the second electrical field.
Implementation Method 2
liquid crystal molecules 132 are inclined towards different directions to form a distribution of a plurality of regions, thereby achieving a display effect of wide viewing angle
Data Source
AI summary
A substrate with a multi-domain vertical alignment pixel structure is provided. The substrate is opposite to a counter substrate with a common electrode, and a liquid crystal layer is disposed between the substrate and the counter substrate. The substrate includes a scan line and a data line, an active device, first and second patterned pixel electrodes and a voltage drop layer. Wherein, the first patterned pixel electrode provides a first electrical field to the liquid crystal layer, and the second patterned pixel electrode provides a second electrical field to the liquid crystal layer. The voltage drop layer makes the first electrical field smaller than the second electrical field.