Cascaded Shift Register Leakage Current Control
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Solution Overview
Problem
The existing display panel technologies face instability in output signals due to cascaded shift registers, affecting the stability of subsequent registers and display effects.
Innovation Solution
A display panel with a driving circuit comprising N stages of cascaded shift registers, each equipped with specific control units to manage node signals and voltage levels, ensuring no leakage current when the output signal is low and maintaining stability across subsequent registers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cascaded shift registers are used to transmit scanning signals, then the display panel can be driven, but the output signal becomes unstable due to leakage current
Solution Approach 1:
A fourth control unit is introduced as an intermediary component between the third control unit and the output signal terminal. This control unit includes a fourth transistor and a fourth capacitor that work together to eliminate leakage current. The fourth transistor acts as a switch that opens when the output signal is at a low level, preventing leakage current from the third node from affecting the output signal, thereby ensuring signal stability while maintaining the cascaded shift register functionality.
Solution Approach 2:
The patent changes the electrical parameters of the shift register circuit by introducing additional control units that can switch between different states. The fourth control unit changes the electrical connection state between nodes based on the output signal level, dynamically adjusting the circuit parameters to prevent leakage current when needed while maintaining normal operation when the output signal is at a high level.
2Device complexity
If the fourth node potential is not controlled, then the circuit is simpler, but leakage current affects the output signal stability
Solution Approach 1:
The control function is segmented into multiple independent control units. The fourth control unit is specifically responsible for controlling the fourth node potential, while the third control unit handles the output signal generation. This segmentation allows each control unit to focus on a specific function, making the overall system more manageable and reliable. The fourth control unit independently manages the leakage current issue without interfering with the output signal generation process.
Solution Approach 2:
The fourth control unit serves as an intermediary between the third control unit and the output signal terminal. It introduces additional control components (fourth transistor and fourth capacitor) that mediate the interaction between the third node and the output signal, preventing leakage current from directly affecting the output while maintaining the overall circuit functionality.
Data Source
AI summary
Provided are a display panel and a display device. The display panel includes a driving circuit comprising N stages of cascaded shift registers. Each shift register includes a first control unit, a second control unit, a third control unit, and a fourth control unit. The first control unit is configured to receive an input signal and control a signal of a first node. The second control unit is configured to receive a first voltage signal and control a signal of a second node. The third control unit is configured to receive a signal of a fourth node and control an output signal, or receive a second voltage signal and control the output signal. The fourth control unit is configured to receive the first voltage signal and a third voltage signal and control the signal of the fourth node.