Double-Gate TFT Layout With Stacked Capacitor for Stable Subpixels
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Solution Overview
Problem
Display devices face challenges in increasing luminous efficiency while maintaining driving stability and characteristic of circuit elements in subpixels, as larger circuit areas reduce light-emitting areas and increased driving characteristics compromise stability.
Innovation Solution
A display device design featuring a driving transistor with double gate electrodes and a capacitor electrode positioned on the top gate electrode, which overlaps part of the channel region, allowing for electric field control to improve current stability and characteristic without increasing the circuit element area in subpixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the area of circuit element disposed in subpixel is increased to improve driving characteristic, then the driving characteristic is improved, but the area of light-emitting region is reduced, thus luminous efficiency is decreased
Solution Approach 1:
The capacitor electrode is positioned on top of the second gate electrode, creating a nested structure where the capacitor is formed within the vertical space above the gate. This nesting allows the capacitor to occupy minimal planar area while still providing sufficient capacitance, thereby improving driving characteristic without reducing the light-emitting area of the subpixel.
Solution Approach 2:
The invention transitions from a planar arrangement of circuit elements to a three-dimensional stacked configuration. By positioning the capacitor electrode vertically above the gate electrode rather than adjacent to it in the same plane, the circuit element occupies significantly less horizontal area, allowing the light-emitting region to expand while maintaining driving performance.
2Stability of the object's composition
If the area of circuit element disposed in subpixel is increased to improve driving stability, then the driving stability is improved, but the area of light-emitting region is reduced, thus luminous efficiency is decreased
Solution Approach 1:
The nested configuration of the capacitor electrode on top of the gate electrode provides sufficient capacitance for driving stability within a compact vertical structure. This ensures stable driving characteristics while minimizing the horizontal footprint of the circuit element, preserving the light-emitting area.
Solution Approach 2:
By utilizing the vertical dimension for capacitor placement, the invention achieves the necessary capacitance for driving stability without expanding the planar area occupied by the circuit element. This dimensional transition allows the light-emitting region to maintain its area while still providing adequate driving stability.
3Reliability
If the capacitor electrode overlaps the channel region, then the electric field control is improved and current stability is enhanced, but the device complexity is increased
Solution Approach 1:
The capacitor electrode serves dual functions: it forms the capacitor necessary for maintaining data voltage and simultaneously acts as a gate electrode that controls the current through the channel region. This multi-functionality enhances current stability through electric field control while avoiding the need for additional separate components, thereby reducing overall device complexity.
Solution Approach 2:
The invention merges the capacitor electrode with the gate electrode structure, combining two previously separate elements into one integrated component. This merging allows the same structure to provide both capacitive storage and active channel control, simplifying the device architecture while improving current stability through enhanced electric field management.
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 current stability and characteristic of the driving transistor, minimizing the occupied area by the circuit element and achieving high-resolution display devices with improved luminous efficiency.
Implementation Method 1
a current stability of the driving transistor can be improved by an electric field control by the capacitor electrode
Data Source
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AI summary
Embodiments of the present disclosure are related to a thin film transistor and a display device, as disposing a capacitor electrode on a gate electrode of the thin film transistor including double gate electrodes, an area where a storage capacitor occupies in a subpixel is reduced and a space availability can be improved. Furthermore, among the double gate electrodes, a gate electrode forming a storage capacitor doesn't overlap a part of a channel, and a part of the capacitor electrode overlaps a part of the channel, so it can be possible to control electric field by the capacitor electrode, thus the thin film transistor having a high output current and a current stability can be provided.