Slanted Gate TFT Layout for Alignment-Tolerant Capacitance Control
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Solution Overview
Problem
In liquid crystal display devices, alignment deviations between the gate electrode and the source/drain electrode of thin film transistors lead to parasitic capacitance differences, causing display abnormalities such as horizontal or vertical stripes, which affect the display quality.
Innovation Solution
The thin film transistor design includes a gate electrode with a first body portion and a first extension portion, and a first electrode with overlapping and compensation ends, which are strategically positioned to maintain a consistent overlapping area despite alignment deviations, thereby compensating for capacitance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gate electrode and source/drain electrode are positioned using conventional alignment methods, then the manufacturing process is simple, but alignment deviations cause parasitic capacitance differences leading to display abnormalities
Solution Approach 1:
The gate electrode is segmented into a first body portion and a first extension portion, while the first electrode is segmented into a first overlapping end, a first compensation end, and a first intermediate portion. This segmentation allows independent optimization of each segment's function to compensate for alignment deviations without requiring complete restructuring of the entire electrode system.
Solution Approach 2:
The patent introduces a spatial dimension solution by extending the gate electrode in a first direction and positioning the first electrode's compensation end to overlap with the extension portion in the same direction. This dimensional arrangement creates a geometric compensation mechanism where the overlapping area remains consistent even when alignment deviations occur in the perpendicular direction.
2Reliability
If the overlapping area between gate electrode and source/drain electrode varies due to alignment deviations, then manufacturing is easier, but parasitic capacitance differences cause display abnormalities
Solution Approach 1:
The first extension portion and first compensation end are designed in advance to counteract the harmful effect of alignment deviations. By pre-positioning these elements to overlap in a specific geometric arrangement, the design proactively compensates for potential misalignment before manufacturing variations occur, ensuring consistent overlapping area and stable parasitic capacitance.
3Ease of manufacture
If conventional thin film transistor structures are used, then device complexity is low, but alignment deviations cause parasitic capacitance differences leading to horizontal or vertical stripes
Solution Approach 1:
The patent converts the harmful effect of alignment deviations into a beneficial compensation mechanism. The first extension portion and first compensation end are specifically designed to utilize the geometric relationship created by alignment variations, transforming potential manufacturing defects into a self-correcting system that maintains consistent overlapping area and eliminates display abnormalities.
Data Source
AI summary
A thin film transistor, an array substrate and a display device are provided. The thin film transistor is on a base substrate and includes a gate electrode, a first electrode, and a second electrode on the base substrate. The gate electrode includes a first body portion and a first extension portion extending along the first direction, electrically connected with the first body portion, and spaced apart from the first body portion by a first spacing. The first electrode includes a first overlapping end, an orthographic projection of the first overlapping end on the base substrate at least partially overlaps with an orthographic projection of the first body portion on the base substrate; a first compensation end at a side of the first overlapping end away from the first body portion, an orthographic projection of the first compensation end on the base substrate at least partially overlaps with an orthographic projection of the first extension portion on the base substrate; and a first intermediate portion connecting the first overlapping end and the first compensation end, an orthographic projection of the first intermediate portion on the base substrate is within an orthographic projection of the first spacing on the base substrate.