Backlight Control Circuit for VRR Display Flicker Mitigation
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Solution Overview
Problem
Variable refresh rate (VRR) techniques in gaming displays cause flicker phenomena due to inconsistent frame period lengths, affecting display quality and potentially leading to premature aging of light-emitting elements in the backlight module.
Innovation Solution
A display equipment and method that includes a backlight control system with a first backlight control circuit generating a main dimming signal during valid data periods and a second backlight control circuit generating a compensation dimming signal during blank periods, ensuring the average brightness of the compensation backlight matches the main backlight, with the peak current value of the compensation dimming signal being less than that of the main dimming signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If VRR techniques are applied to dynamically change frame period length, then screen tearing and delay are solved, but flicker phenomenon occurs due to inconsistent frame period lengths
Solution Approach 1:
The patent divides the backlight control into two separate circuits: a first backlight control circuit that controls the backlight during valid data periods, and a second backlight control circuit that controls the backlight during blank periods. This segmentation allows independent optimization of backlight control for each period type, solving the flicker problem caused by inconsistent frame period lengths in VRR displays
Solution Approach 2:
The patent dynamically adjusts the backlight brightness parameters based on the frame period length variations in VRR mode. By changing the backlight control parameters (brightness, duration) according to the specific timing requirements of each frame period, the system maintains consistent perceived brightness while accommodating variable refresh rates
2Illumination intensity
If backlight provides continuous illumination during blank periods, then flicker is reduced, but light-emitting elements age prematurely due to excessive current
Solution Approach 1:
The patent applies different quality standards to different time periods: during valid data periods, the backlight operates at normal brightness levels, while during blank periods, the backlight operates at reduced brightness levels. This local quality differentiation maintains flicker-free display during visible periods while extending backlight element lifespan during invisible periods
Solution Approach 2:
Instead of providing full backlight illumination during blank periods (excessive action), the patent provides partial backlight illumination at reduced current levels. This partial action is sufficient to prevent flicker perception while avoiding the excessive stress that would cause premature aging of light-emitting elements
Data Source
AI summary
The invention provides a display equipment, an operation method thereof, and a backlight control device. The display equipment includes a display panel, a backlight module, an image processing circuit, a panel control circuit, a first backlight control circuit, and a second backlight control circuit. The image processing circuit provides a VRR video frame to the panel control circuit. The first backlight control circuit generates a main dimming signal to the backlight module during a valid data period of the VRR video frame according to a first timing information of the image processing circuit. The second backlight control circuit generates a compensation dimming signal to the backlight module during a blank period of the VRR video frame according to a second timing information of the image processing circuit. In particular, a peak current value of the compensation dimming signal is less than a peak current value of the main dimming signal.