OLED Pixel Emission Timing for Variable Refresh Rate Flicker
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Solution Overview
Problem
Display devices experience variable refresh rate flicker due to differences in luminance decay between refresh rates, particularly under strong ambient light conditions, as the luminance tuning or calibration does not accurately compensate for these changes.
Innovation Solution
Implementing different time delays between programming and emission of pixels at varying refresh rates to mitigate luminance differences, with longer delays at higher refresh rates to reduce perceptible flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the display device operates at a higher refresh rate, then the presentation smoothness is improved, but the power consumption increases and luminance consistency deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of pixel emission characteristics based on refresh rate. At different refresh rates (60Hz, 90Hz, 120Hz), the display device applies different delay times between programming and emission, and different emission durations, allowing the system to adapt its operation dynamically to balance smoothness, power consumption, and luminance consistency
Solution Approach 2:
The patent changes key operational parameters (delay time, emission duration) based on refresh rate. Specifically, at higher refresh rates, the emission duration is reduced and delay time is adjusted to compensate for faster luminance decay, maintaining consistent perceived brightness while managing power consumption across different refresh rates
2Illumination intensity
If the emission duration is extended to maintain luminance, then the brightness consistency is improved, but the power consumption increases
Solution Approach 1:
The patent adjusts the emission duration parameter based on refresh rate and ambient light conditions. At higher refresh rates where luminance decay is more pronounced, the emission duration is optimized to provide sufficient luminance while avoiding excessive power consumption, creating a dynamic balance between brightness consistency and energy usage
3Illumination intensity
If the delay time between programming and emission is increased, then the luminance consistency across refresh rates is improved, but the response time increases
Solution Approach 1:
The patent implements refresh rate-specific delay time adjustments. The delay time is increased at higher refresh rates to compensate for faster luminance decay and maintain consistent perceived brightness, but this increase is calibrated to minimize impact on overall response time, creating an optimized balance between luminance consistency and temporal response
Data Source
AI summary
In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for operating a display device. A pixel of a the display device is refreshed while the display device is operating at a first refresh rate, including by: turning off emission of the LED; programming a driving transistor that drives the LED; and turning on emission of the LED a first delay of time after the programming of the driving transistor. The pixel of the display device is refreshed while the display device is operating at a second refresh rate, including by: turning off emission of the LED; programming the driving transistor that drives the LED; and turning on emission of the LED a second delay of time after the programming of the driving transistor.