Shift Register Gate Electrode Cuts Reduce Parasitic Capacitance
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Solution Overview
Problem
Conventional shift registers with comb-shaped source/drain structures in gate drivers for display devices suffer from parasitic capacitance issues, leading to display quality deterioration, reduced operation margin, and potential malfunctions due to leakage currents and voltage instability.
Innovation Solution
A shift register design featuring bottom gate thin-film transistors with a comb-shaped source/drain structure, where the gate electrode includes cuts or openings in regions overlapping with the source and drain electrodes to reduce parasitic capacitance and improve bootstrap effects, thereby stabilizing the operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional comb-shaped source/drain structure is used in the shift register, then the manufacturing process is simple, but parasitic capacitance increases causing display quality deterioration and operation malfunctions
Solution Approach 1:
The gate electrode is divided into multiple segments with cuts or openings in the overlapping regions with source and drain electrodes. This segmentation reduces the continuous overlap area, thereby decreasing parasitic capacitance while maintaining the comb-shaped source/drain structure for easy manufacturing
Solution Approach 2:
The gate electrode is modified locally by introducing cuts or openings only in the regions where it overlaps with source and drain electrodes, while maintaining the original structure in other regions. This local modification reduces parasitic capacitance without changing the overall manufacturing process
2Reliability
If the gate electrode is modified with cuts or openings to reduce parasitic capacitance, then operation stability improves, but the manufacturing process becomes more complex
Solution Approach 1:
The gate electrode is segmented with cuts or openings that can be formed using standard photolithography and etching processes. This segmentation reduces parasitic capacitance while the manufacturing complexity remains within acceptable limits for conventional TFT fabrication
3Ease of manufacture
If amorphous silicon TFTs are used in the gate driver, then production costs are reduced, but high driving voltage is required due to low mobility
Solution Approach 1:
The invention modifies the gate electrode geometry (adding cuts or openings) to reduce parasitic capacitance, which improves the switching characteristics of amorphous silicon TFTs. This allows amorphous silicon TFTs to operate more efficiently at the required high voltages, maintaining cost advantages while improving performance
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 effectively suppresses parasitic capacitance, enhances the bootstrap effect, and stabilizes the operation of the shift register, improving display quality and increasing yield while reducing costs by using amorphous silicon for the TFTs.
Implementation Method 1
the gate electrode being provided with at least one of a cut and an opening in at least one of a region overlapping with a source electrode and a region overlapping with a drain electrode
Implementation Method 2
enhances the bootstrap effect, and stabilizes the operation of the shift register
Data Source
AI summary
The present invention provides a shift register and a display device, each of which operates stably. The present invention relate to a shift register, comprising a thin-film transistor which includes a source electrode, a drain electrode, and a gate electrode, the thin-film transistor being a bottom gate thin-film transistor which includes a comb-shaped source/drain structure, the gate electrode being provided with at least one of a cut and an opening in at least one of a region overlapping with the source electrode and a region overlapping with the drain electrode.