OLED Emission Driver Voltage Control for IR Drop
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Solution Overview
Problem
OLED displays experience brightness variations due to high current usage, leading to IR drop issues, which existing technologies have not adequately addressed.
Innovation Solution
A display device with an emission driver that provides first and second emission power sources with a difference value that varies over time, including light emitting and non-emitting periods, to manage IR drop and maintain uniform brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high current is supplied to OLEDs to achieve sufficient brightness, then light emission intensity is improved, but IR drop increases causing brightness variation
Solution Approach 1:
The emission power source voltage is dynamically adjusted based on the display timing. During light emitting periods, the voltage difference between first and second emission power sources is maintained at substantially equal to or greater than a reference value to ensure sufficient brightness. During light non-emitting periods, the voltage difference is adjusted to be less than the reference value, which compensates for IR drop and maintains brightness uniformity across the display panel.
Solution Approach 2:
The patent changes the voltage parameter of the emission power sources based on operational timing. The first emission power source voltage is adjusted to have different levels during light emitting periods versus light non-emitting periods, while the second emission power source voltage is also adjusted accordingly. This parameter change approach allows the system to optimize both brightness intensity and brightness uniformity by adapting the voltage levels to the specific operational phase.
2Illumination intensity
If the difference value between first and second emission power sources is maintained high during light emitting periods, then brightness is improved, but IR drop increases causing brightness variation within the same frame
Solution Approach 1:
The emission driver operates with periodic voltage adjustments synchronized to the display frame timing. Within each frame, the voltage difference between emission power sources is periodically modified - maintained high during light emitting periods for brightness, and reduced during light non-emitting periods to compensate for IR drop. This periodic action occurs at multiple time points within each frame, creating a rhythmic compensation pattern that addresses brightness uniformity while maintaining overall brightness levels.
Solution Approach 2:
The system implements a feedback mechanism where the emission driver monitors the operational timing and adjusts the emission power source voltages accordingly. The voltage adjustment is based on feedback from the display timing signals that indicate when light emitting periods and light non-emitting periods occur. This feedback loop allows the system to automatically compensate for IR drop effects and maintain brightness uniformity across the display panel.
Data Source
AI summary
A display device includes: a display panel for displaying frames during an elapse of time; and an emission driver for providing first and second emission power sources to the display panel, wherein: each of the frames comprises a first light emitting period, a light non-emitting period and a second light emitting period according to a time sequence, a difference value between the first and second emission power sources is substantially equal to or greater than a reference value during the first and second light emitting periods, and is less than the reference value during the light non-emitting period, and the difference value between the first and second emission power sources decreases over an elapse of time during the first light emitting period, and increases over an elapse of time during the second light emitting period.