Pixel Circuit Overlapping Capacitors for Stable High-Speed Driving
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Solution Overview
Problem
Existing display devices face challenges with capacitor capacity limitations and voltage fluctuations affecting driving transistors due to boost capacitors during self-scan periods, leading to inefficiencies in high-speed driving operations.
Innovation Solution
The display device incorporates a novel pixel circuit design with overlapping capacitor electrodes and additional hold capacitors, along with a connection electrode and extension portions, enhancing capacitor capacity and reducing voltage fluctuations by blocking connections during self-scan periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a boost capacitor is connected to the driving transistor, then the driving transistor can be driven at high speed, but the voltage of the control electrode fluctuates during self-scan periods
Solution Approach 1:
The patent extracts the harmful interaction between the boost capacitor and driving transistor during self-scan periods by introducing a blocking mechanism. The blocking transistor is specifically activated during self-scan to prevent the boost capacitor from affecting the driving transistor's control electrode voltage, thereby maintaining voltage stability while preserving high-speed driving capability during normal operation.
Solution Approach 2:
The patent implements dynamic control of the circuit configuration by using a blocking transistor that can be selectively activated or deactivated. During self-scan periods, the blocking transistor is activated to isolate the boost capacitor from the driving transistor. During normal driving periods, the blocking transistor is deactivated to allow the boost capacitor to enhance driving speed. This dynamic switching resolves the contradiction between speed enhancement and voltage stability.
2Stability of the object's composition
If capacitor capacity is increased to improve holding capability, then voltage stability improves, but the device area increases
Solution Approach 1:
The patent applies the nesting principle by placing the hold capacitor electrode and storage capacitor electrode in an overlapping configuration. The hold capacitor's first electrode is positioned to overlap with the storage capacitor's second electrode, allowing both capacitors to share common physical space. This nested arrangement enables increased total capacitor capacity while minimizing the additional area required, as the capacitors are embedded within each other's spatial footprint rather than being placed side-by-side.
Data Source
AI summary
A display device includes a substrate, a first active pattern above the substrate, a first gate layer above the first active pattern, and including a first capacitor electrode, a second gate layer above the first gate layer, and including a second capacitor electrode overlapping the first capacitor electrode, a second active pattern above the second gate layer, and including an extension portion above the second capacitor electrode, and a connection electrode above the second active pattern, and connecting the extension portion and the first capacitor electrode.