Pixel Driving Circuit Voltage Initialization for Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-resolution display devices with densely arranged pixels, the data voltage written during one frame period can affect the image displayed in the next frame, leading to deteriorated display quality due to current leakage and threshold voltage deviations.
Innovation Solution
A display device and driving method that initialize a capacitor in each pixel to eliminate current leakage by reducing the power supply voltage to a level between low and high, preventing current leakage through the driving transistor during data writing, and using a combination of transistors and capacitors to manage voltage levels effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixels are densely arranged to achieve high resolution, then display resolution is improved, but current leakage between pixels increases causing display quality deterioration
Solution Approach 1:
The patent applies preliminary action by introducing an initializing period before the data writing period. During this initializing period, the power supply voltage is reduced to a middle level to pre-establish a stable voltage state and eliminate current leakage paths. This preliminary voltage stabilization prevents current leakage from affecting the subsequent data writing process, thereby enabling dense pixel arrangement without quality deterioration.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the power supply voltage to three distinct levels: high voltage during the light emission period for normal operation, middle voltage during the initializing period to eliminate current leakage, and low voltage during the data writing period to prevent threshold voltage shifts. This multi-level voltage control resolves the contradiction by changing the voltage parameter to prevent harmful current leakage while maintaining high resolution.
2Reliability
If complex transistor structures are used to compensate for threshold voltage deviation, then display quality is improved, but device complexity increases making dense pixel arrangement difficult
Solution Approach 1:
The patent uses parameter changes by implementing a multi-level power supply voltage control scheme. Instead of using complex transistor structures for compensation, the system dynamically adjusts voltage parameters (high, middle, low levels) during different operational phases to compensate for threshold voltage deviations and eliminate current leakage, thereby achieving reliable display quality with simpler pixel structures.
Solution Approach 2:
The patent applies preliminary action by performing voltage initialization before data writing. During the initializing period, the power supply is set to a middle level to pre-stabilize voltage conditions and eliminate leakage paths. This preliminary stabilization reduces the need for complex compensation structures in subsequent operations.
3Power
If power supply voltage is maintained at high level during data writing, then driving performance is improved, but current leakage through transistors increases affecting next frame display
Solution Approach 1:
The patent applies preliminary action by reducing the power supply voltage to a middle level during the initializing period before data writing. This preliminary voltage reduction eliminates current leakage paths and stabilizes the electrical state, ensuring that when high voltage is applied during the light emission period, no harmful current leakage occurs that would affect the next frame display.
Solution Approach 2:
The patent employs parameter changes by implementing dynamic voltage control with three distinct levels. The power supply voltage is changed from high (during light emission) to middle (during initialization) to low (during data writing), and then back to high. This parameter change strategy prevents current leakage during critical periods while maintaining driving performance when needed.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A display device including: a scan driver that transmits scan signals to scan lines; a data driver that data signals to data lines; and a display portion that includes pixels, respectively connected to the corresponding scan lines and corresponding data lines, and displays an image by the pixels that simultaneously emit light according to the corresponding data signals, wherein each of pixels includes: an organic light emitting diode; a first transistor that includes a gate connected to a first node, and is connected between first power and an anode of the organic light emitting diode; a second transistor that includes a gate connected to a corresponding scan line and transmits the corresponding data signal to the first node; and a first capacitor that is connected to the first node, and stores a data voltage according to the data signal.