2Tr/1C Drive Circuit Node Potential Control
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Solution Overview
Problem
The existing 2Tr/1C drive circuit for organic electroluminescence display elements experiences a decrease in luminance due to potential changes in the second node ND2, leading to increased power consumption when attempting to maintain luminance, as the potential difference between the first and second nodes decreases, affecting the drain current and thus the light emitted by the display element.
Innovation Solution
The method involves executing threshold voltage cancel processing and write processing while applying a first and second reference voltage to the cathode electrode of the light emitting part, with the second reference voltage being lower than the first, to suppress potential changes in the second node ND2, allowing for smaller video signal amplitudes and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the potential difference between the first node ND1 and the second node ND2 is increased to maintain luminance, then the luminance is maintained, but the power consumption increases
Solution Approach 1:
The patent applies preliminary action by executing threshold voltage cancel processing before the write processing. This preliminary processing stabilizes the potential of the second node ND2, preventing potential changes that would otherwise require increased video signal amplitudes to maintain luminance, thereby reducing power consumption while maintaining display performance
Solution Approach 2:
The patent changes the parameter of reference voltage applied to the cathode electrode. By switching between a first reference voltage during threshold voltage cancel processing and a second reference voltage during write processing, the system optimizes the potential difference control to maintain luminance with reduced power consumption
2Illumination intensity
If the amplitude of video signal is increased to compensate for potential changes in the second node ND2, then the luminance is maintained, but the device complexity increases
Solution Approach 1:
The patent stabilizes the potential of the second node ND2 through preliminary threshold voltage cancel processing, which eliminates the need for complex dynamic adjustments of video signal amplitudes. This preliminary stabilization simplifies the signal control mechanism while maintaining consistent luminance output
Solution Approach 2:
The patent simplifies device complexity by changing the reference voltage parameter applied to the cathode electrode based on processing stage. This parameter change approach provides systematic control over potential differences without requiring complex real-time signal adjustment mechanisms
Data Source
AI summary
Disclosed herein is a method for driving a display element including a current-driven light emitting part and a drive circuit, the drive circuit including a write transistor, a drive transistor, and a capacitive part, the method including the steps of: executing threshold voltage cancel processing of changing potential of the second node toward potential obtained by subtracting threshold voltage of the drive transistor from potential of the first node in a state in which the potential of the first node is kept; and executing write processing of applying a video signal from the data line to the first node via the write transistor turned to an on-state by a scan signal from the scan line.