OLED Flicker Reduction via APL-Based Luminance Control
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Solution Overview
Problem
Organic light-emitting display (OLED) devices experience flicker due to abrupt changes in average picture level (APL) caused by peak luminance control (PLC) functions, leading to sharp luminance changes and overall luminance fluctuations.
Innovation Solution
An image control circuit that calculates and compares APLs for consecutive time intervals, generates an adjusted-APL to buffer luminance changes, and adjusts the display panel's luminance based on this adjusted value, using a dimming slope to reduce the rate of change and minimize flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If peak luminance control (PLC) function is applied to save power consumption, then power consumption is reduced, but flicker occurs due to abrupt luminance changes
Solution Approach 1:
The patent calculates APL in advance for the next frame before displaying it, and uses this predicted APL value to adjust the luminance transition. This preliminary action allows the system to prepare for upcoming luminance changes and smooth transitions, preventing abrupt changes that cause flicker while maintaining PLC power-saving functionality.
Solution Approach 2:
The patent dynamically adjusts the luminance change rate based on the difference between current and next frame APL values. When APL changes significantly, the system reduces the transition speed to avoid abrupt changes. This dynamic adjustment creates a flexible control mechanism that adapts to different imaging conditions, eliminating flicker while preserving power consumption benefits.
2Loss of energy
If APL changes abruptly between frames, then power consumption is saved through PLC, but luminance stability deteriorates causing flicker
Solution Approach 1:
The system calculates the APL for the next frame in advance and uses this predicted value to control the luminance transition. By preparing the APL value before the frame is displayed, the system can smooth the transition and maintain luminance stability without sacrificing the power-saving benefits of PLC.
Solution Approach 2:
The patent uses the calculated APL value as feedback to adjust the luminance transition speed. The system continuously monitors APL changes and adjusts the transition dynamically, creating a closed-loop control system that maintains luminance stability while achieving power consumption reduction through PLC.
3Speed
If luminance adjustment is applied without APL analysis, then response speed is fast, but flicker occurs due to unsmoothed transitions
Solution Approach 1:
The system performs APL calculation in advance for the next frame and uses this predicted APL to control the luminance transition speed. This preliminary analysis allows the system to maintain fast response while smoothing transitions, as the APL information is already prepared before the frame needs to be displayed.
Data Source
AI summary
Disclosed is a display device that may include a display panel; and a plurality of drivers that control the display panel to display images and include an image control circuit, the image control circuit including: an average picture level (APL) circuit that analyzes first and second input image data for first and second time intervals and calculates first and second APLs, respectively, wherein the second time interval precedes the first time interval, an adjusted-APL generator that generates an adjusted-APL for the first input image data based on a comparison between the first and second APLs, and a luminance adjustment controller that adjusts a luminance of the display panel for the first input image data based on the adjusted-APL.