Display Panel Flicker Reduction via Frequency Mode Detection
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Solution Overview
Problem
Free-sync display technology experiences flickering issues due to brightness adjustments during frequency changes, particularly in saw mode, where frequency gradually changes from low to high and back, leading to visible brightness jumps and flickers despite voltage adjustment efforts.
Innovation Solution
A display method and device that determines whether the display panel is in a specific display mode by analyzing the difference in frequencies between consecutive frames, and when in that mode, it turns off the brightness adjustment function to prevent flickering, using a timing controller and power management chip to manage voltage adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If brightness adjustment function is enabled to compensate for brightness changes during frequency transitions, then brightness compensation is achieved, but brightness jumps and flickering occur at frequency change nodes
Solution Approach 1:
The patent inverts the conventional approach by not adjusting brightness during frequency transitions, but instead maintaining fixed brightness. This counterintuitive solution eliminates the brightness jumps and flickering that occur when voltage adjustment is applied at frequency change nodes, particularly in saw mode operation.
Solution Approach 2:
The patent changes the brightness control parameter from dynamic voltage adjustment to fixed voltage maintenance during frequency transitions. By keeping the brightness parameter constant rather than adjusting it based on frequency changes, the system avoids the flickering issues that arise from voltage adjustment inaccuracies.
2Reliability
If voltage adjustment is used to improve brightness compensation at low frequency, then flicker issue in ramp mode is improved, but brightness adjustment accuracy is limited by power management chip resolution
Solution Approach 1:
The patent extracts the brightness adjustment function during frequency transitions, removing it entirely from the operation. Instead of attempting to adjust voltage to compensate for brightness changes, the system disables this adjustment mechanism, thereby eliminating the accuracy limitations imposed by the power management chip's voltage resolution.
Solution Approach 2:
The patent sacrifices brightness compensation capability during frequency transitions to achieve overall display stability. By accepting temporary brightness uniformity across different refresh rates, the system avoids the complex and imprecise voltage adjustment mechanism that is limited by hardware resolution.
3Illumination intensity
If frequency switching is used to improve brightness variation, then brightness consistency is improved, but different frequencies cause brightness differences and flickering
Solution Approach 1:
The patent makes the display panel operate universally across different refresh rates without mode-specific brightness adjustment. By applying a uniform brightness maintenance strategy across all frequency transitions (both ramp and saw modes), the system eliminates the need for mode-specific compensation that causes flickering.
Data Source
AI summary
A display method of a display panel includes determining whether the display panel is in a frequency conversion state, if the display panel is in a frequency conversion state, acquiring a first frequency and a second frequency corresponding to two adjacent frames consecutively for multiple times, determining whether the display panel is in a first display mode according to a difference between the first frequency and the second frequency obtained multiple times, and if the display panel is in the first display mode, turn off a brightness adjustment function of the display panel.