Pixel Driving Circuit for OLED Luminous Efficiency and Color Stability
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Solution Overview
Problem
Self-luminous devices experience decreased luminous efficiency and color coordinate changes due to varying current densities, affecting their performance in display technologies.
Innovation Solution
A pixel driving circuit comprising a signal control sub-circuit and a time control sub-circuit, which includes transistors and capacitors to manage data signals, power supply voltages, and enable signals, allowing for precise control of the turn-on time of transistors to optimize the working time of current-driven light-emitting devices, thereby maintaining high luminous efficiency and stable color coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If current density through self-luminous devices is reduced, then power consumption decreases, but luminous efficiency decreases
Solution Approach 1:
The patent applies periodic action by controlling the light-emitting device to operate in pulsed intervals rather than continuously. The driving circuit generates periodic driving signals that turn the light-emitting device on and off at controlled durations, enabling the device to operate at high current density only during active light-emitting periods while remaining off during non-emitting periods. This periodic operation allows the average power consumption to be reduced while maintaining high luminous efficiency during the active periods when the device operates at optimal current density.
2Loss of energy
If current density through self-luminous devices is reduced, then power consumption decreases, but color coordinates become unstable
Solution Approach 1:
The periodic action principle maintains color coordinate stability by ensuring that during each active light-emitting period, the device operates at a consistent, optimized current density. The driving circuit controls the duration and timing of these periodic pulses to maintain stable color characteristics while reducing overall power consumption through controlled off-periods.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the driving current parameters and pulse duration based on display requirements. The driving circuit modifies current density, pulse width, and frequency parameters to optimize both color stability and power consumption, allowing the system to maintain accurate color coordinates across different operating conditions and grayscale levels.
3Device complexity
If simple driving circuits are used, then device complexity is low, but control precision over light-emitting duration is insufficient
Solution Approach 1:
The driving circuit is segmented into multiple functional sub-circuits, each responsible for specific control tasks such as signal generation, timing control, current regulation, and pixel addressing. This segmentation allows each sub-circuit to be optimized for its specific function, achieving high control precision over light-emitting duration and current density while keeping the overall circuit design modular and manageable.
Solution Approach 2:
The driving circuit incorporates dynamic control mechanisms that adjust driving parameters in real-time based on display requirements. The circuit dynamically modifies current density, pulse duration, and timing parameters to achieve precise control over light-emitting characteristics, enabling accurate grayscale representation and color stability through adaptive parameter adjustment rather than fixed circuit configurations.
Data Source
AI summary
A pixel driving circuit includes a signal control sub-circuit and a time control sub-circuit. The signal control sub-circuit includes a first driving sub-circuit connected to a first node. The signal control sub-circuit is configured to: write at least a first data signal into the first node, and enable the first driving sub-circuit to output a driving signal according to the first data signal and a first power supply voltage signal. The time control sub-circuit includes a second driving sub-circuit including a first transistor connected to a second node and the signal control sub-circuit. The time control sub-circuit is configured to: transmit a second power supply voltage signal and a third power supply voltage signal to the second node in different periods, so as to control a turn-on time of the first transistor and transmit the driving signal to an element to be driven when the first transistor is turned on.