Pixel Driving Circuit for OLED Brightness and Power Control
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Solution Overview
Problem
Self-luminous devices in display panels face uniformity issues due to varying turn-on voltages and photoelectric conversion properties, leading to decreased luminous efficiency and increased power consumption, affecting display quality.
Innovation Solution
A pixel driving circuit comprising a driving control sub-circuit and a time control sub-circuit, which write and manage data and voltage signals to control the operation of current-driven light-emitting diodes, ensuring consistent brightness and reduced power consumption by adjusting the duration and magnitude of the driving signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the current density flowing through the self-luminous device is reduced to achieve lower brightness, then the luminous efficiency decreases and power consumption increases, but the display quality is affected
Solution Approach 1:
The patent applies periodic action by controlling the light-emitting device to operate in pulsed modes rather than continuous operation. The driving circuit generates periodic driving signals that turn the light-emitting device on and off at controlled durations, enabling brightness modulation while maintaining high current density during active periods. This resolves the contradiction by achieving lower average brightness (reducing power consumption) without operating at low current density (maintaining luminous efficiency).
Solution Approach 2:
The patent implements dynamics by making the operating duration of the light-emitting device variable and controllable. The driving circuit dynamically adjusts the on-time and off-time periods based on desired brightness levels, allowing the system to adapt between different operating states. This dynamic control enables optimization of power consumption while maintaining high current density during active periods, resolving the contradiction between brightness control and power efficiency.
2Illumination intensity
If the current density flowing through the self-luminous device is reduced to achieve lower brightness, then the luminous efficiency decreases, but the display quality is affected
Solution Approach 1:
By using periodic driving signals with controlled duty cycles, the patent maintains high current density during active periods (ensuring good display quality and luminous efficiency) while achieving lower average brightness through reduced on-time. This resolves the contradiction by decoupling average brightness from current density level.
Solution Approach 2:
The patent ensures continuous control capability by maintaining the light-emitting device in a ready state with periodic activation. The driving circuit continuously monitors and adjusts the operating duration to maintain optimal current density levels during active periods, ensuring display quality is not compromised while achieving desired brightness levels through temporal control rather than amplitude reduction.
Data Source
AI summary
A pixel driving circuit includes a driving control sub-circuit having a first driving sub-circuit and a time control sub-circuit having a second driving sub-circuit. The driving control sub-circuit is configured to: be connected to an element to be driven, write a first data signal into the first driving sub-circuit, enable the first driving sub-circuit to output a driving signal to drive the element to operate. The time control sub-circuit is configured to: write a second voltage signal and a second data signal into the second driving sub-circuit, write a fourth voltage signal into the second driving sub-circuit, connect the second driving sub-circuit to a third voltage signal terminal and the first driving sub-circuit. The second driving sub-circuit is configured to output a third voltage signal to the first driving sub-circuit to enable the first driving sub-circuit to stop outputting the driving signal to control operating duration of the element.