Asymmetric Comb-Shaped Drain Electrode for Parasitic Capacitance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The variation in gate-drain electrode parasitic capacitance due to misalignments during the manufacturing process of thin film transistors leads to inconsistent feed-through voltages, causing display picture quality degradation such as flickering in liquid crystal display devices.
Innovation Solution
A pixel structure design featuring a comb-shaped drain electrode with protrusion and connecting parts that maintain a constant overlapping area with the gate electrode, ensuring consistent parasitic capacitance regardless of manufacturing misalignments, by aligning the widths of the protrusion and connecting parts with the gate electrode margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional thin film transistor manufacturing process is used, then manufacturing simplicity is maintained, but gate-drain electrode parasitic capacitance varies due to misalignments
Solution Approach 1:
The drain electrode is designed with an asymmetric comb-shaped structure featuring a protrusion part extending beyond the gate electrode and a connecting part within the gate electrode region. This asymmetric configuration ensures that the overlapping area between gate and drain electrodes remains constant even when misalignments occur during manufacturing, thereby maintaining consistent parasitic capacitance values across different pixels.
Solution Approach 2:
The drain electrode structure is pre-configured with specifically designed overlapping regions (protrusion part and connecting part) that compensate for potential misalignments before manufacturing errors occur. By establishing the correct geometric relationship in advance, the design ensures that variations in electrode positioning do not affect the final parasitic capacitance consistency.
2Reliability
If gate electrode and drain electrode overlapping area varies, then feed-through voltage varies, but display picture quality degrades
Solution Approach 1:
The asymmetric comb-shaped drain electrode design with protrusion and connecting parts creates a structure where the total overlapping area with the gate electrode remains constant regardless of horizontal misalignments. This geometric compensation ensures consistent parasitic capacitance and eliminates feed-through voltage variations that would otherwise cause display picture quality degradation.
3Adaptability or versatility
If misalignment tolerance is improved, then parasitic capacitance consistency is maintained, but electrode structure becomes more complex
Solution Approach 1:
The comb-shaped drain electrode with its asymmetric protrusion and connecting parts is specifically designed to provide misalignment tolerance. The geometric configuration ensures that variations in electrode positioning are compensated, maintaining constant overlapping area and parasitic capacitance.
Solution Approach 2:
The comb-shaped drain electrode structure serves multiple functions: it provides the necessary electrical connection, establishes a defined overlapping area with the gate electrode, and simultaneously compensates for manufacturing misalignments. This multi-functionality achieves high misalignment tolerance without requiring separate compensation mechanisms.
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 maintains consistent gate-drain electrode parasitic capacitance, preventing display quality degradation and improving the misalignment tolerance, resulting in stable and high-quality display images even with low manufacturing accuracy.
Implementation Method 1
the gate electrode at least partially overlaps the drain electrode, therefore a gate-drain electrode parasitic capacitance (referred to as Cgd) often exists due to the overlapping of the gate electrode and the drain electrode
Data Source
AI summary
A pixel structure includes a scan line, a data line, a gate electrode, a semiconductor layer, a source electrode, a drain electrode including a comb-shaped part surrounding the source electrode and a connecting part, and a pixel electrode electrically connected to the drain electrode. The scan line and the data line are arranged intersectedly and electrically insulated from each other. At least a portion of the source electrode and the drain electrode are disposed on the semiconductor layer. At least one branch of the comb-shaped part extends outside one side of the gate electrode to form a protrusion part. The connecting part extends from the comb-shaped part beyond the other side of the gate electrode. The protrusion part and the connecting part aligned with the margin of the gate electrode have a first width and a third width respectively, wherein the first width substantially equals to the third width.