Display Device Gate-Off Voltage Correction Circuit
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Solution Overview
Problem
Liquid crystal display (LCD) devices face challenges in minimizing leakage current due to inadequate control of gate-off voltage, leading to inefficiencies and potential damage over time.
Innovation Solution
A display device is designed with a compensation circuit that detects changes in drain current and gate voltage, generating a compensation voltage to correct the gate-off voltage in real time, thereby minimizing leakage current through the use of dummy switching elements and a power supply circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate-off voltage is not corrected, then the device structure remains simple, but the leakage current increases causing inefficiency and potential damage
Solution Approach 1:
The compensation circuit performs preliminary detection of the switching element's characteristics (threshold voltage, drain current) before the actual switching operation. Based on this preliminary detection, the gate-off voltage is pre-corrected to an optimal value, ensuring minimal leakage current from the outset without requiring complex real-time adjustment mechanisms during operation.
Solution Approach 2:
A dedicated compensation circuit is introduced as an intermediary component between the power supply and the switching element. This intermediary circuit specifically handles the gate-off voltage correction function, isolating the complexity from the main switching circuit while achieving precise leakage current control through specialized voltage adjustment.
2Reliability
If the gate-off voltage is corrected in real time, then the leakage current is minimized, but the control complexity increases
Solution Approach 1:
The compensation circuit implements a feedback mechanism where the actual drain current and threshold voltage of the switching element are continuously monitored. Based on this feedback information, the gate-off voltage is automatically adjusted to maintain optimal leakage current levels, eliminating the need for manual calibration or complex external control systems.
Solution Approach 2:
The switching element itself provides the necessary information for its own optimization. By detecting the element's inherent characteristics (threshold voltage shifts, current levels), the compensation circuit enables the switching element to self-correct its operating conditions, achieving minimal leakage current without external intervention or complex control algorithms.
3Measurement precision
If dummy switching elements are added for detection, then the gate-off voltage can be accurately corrected, but the device area increases
Solution Approach 1:
Instead of using complex sensing mechanisms, the patent employs simplified dummy switching elements that replicate the essential electrical characteristics of the main switching elements. These dummy elements serve as accurate but compact models for detecting threshold voltage and drain current, providing sufficient measurement precision without requiring elaborate detection structures.
Solution Approach 2:
The dummy switching elements serve multiple functions simultaneously: they act as test structures for characterizing switching element parameters, provide reference values for compensation calculations, and can potentially serve as backup or calibration elements. This multi-functionality maximizes the utility of the added components while minimizing the overall area overhead.
Data Source
AI summary
A display device includes: a substrate; a gate line, a dummy gate line, a data line, a dummy data line, a pixel electrode, and a dummy pixel electrode, each disposed on the substrate; a switching element connected to the gate line, the data line, and the pixel electrode; a dummy switching element connected to the dummy gate line, the dummy data line, and the dummy pixel electrode; a compensation circuit detecting a change amount of a drain current based on drain currents generated from the dummy pixel at different time points, and detecting a change amount of a gate voltage of the dummy switching element based on the change amount of the drain current; a power supply circuit outputting a corrected gate-off voltage based on the change amount of the gate voltage; and a gate driver applying the corrected gate-off voltage to the gate line.