Liquid Crystal Display Timing Controller Variable Frame Flicker
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Solution Overview
Problem
Liquid crystal display devices experience tearing and flicker issues due to varying image frame rates, leading to suboptimal display quality, as existing adaptive synchronization techniques affect the average luminance and visibility of flicker phenomena.
Innovation Solution
A liquid crystal display device employing a timing controller that generates a light-source controlling signal with a high level during a light-on period and a low level during a light-off period, adjusted based on frame frequency, to maintain consistent light-on periods across variable frequency modes, thereby reducing luminance differences and flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive synchronization technique is used to adjust vertical blank interval to match variable image frame rate, then tearing phenomenon is reduced, but average luminance of liquid crystal display panel changes for each frame causing flicker
Solution Approach 1:
The patent applies parameter changes by adjusting the light-off period duration according to different frame frequencies. When frame frequency varies, the controller dynamically changes the light-off period length to compensate for luminance variations caused by different vertical blank interval lengths, thereby maintaining consistent average luminance across frames while preserving the adaptive synchronization benefit of variable vertical blank intervals
Solution Approach 2:
The patent implements periodic action by applying black insertion during light-off periods at specific frame rates (60Hz, 75Hz, 85Hz, 100Hz, 120Hz). This periodic black insertion compensates for luminance differences caused by varying vertical blank intervals, reducing flicker while maintaining the adaptive synchronization that prevents tearing
2Adaptability or versatility
If vertical blank interval is increased or decreased to match variable image frame rate, then frame rate synchronization is improved, but luminance difference between frames increases causing visible flicker
Solution Approach 1:
The patent dynamically changes the light-off period parameter based on detected frame frequency. When a lower frame frequency is detected, the light-off period is extended to compensate for the longer vertical blank interval, maintaining consistent luminance. This allows the display to adapt to various frame rates while preserving luminance stability
Solution Approach 2:
The patent uses feedback by detecting the actual frame frequency from incoming video signals and adjusting the light-off period duration accordingly. The controller continuously monitors frame rate and modifies backlight timing parameters in real-time to compensate for luminance variations, creating a closed-loop system that maintains luminance consistency across different frame rates
Data Source
AI summary
A liquid crystal display device comprising, a liquid crystal display panel, a timing controller configured to output a light-source controlling signal during a variable frequency mode comprising a plurality of frames with variable frame frequencies, the light-source controlling signal having a high level during a light-on period preset in an early period of a frame of the plurality of frames and a low level during a light-off period preset to a length according to a frame frequency in a latter period of the frame of the plurality of frames, and a light source configured to emit light during the light-on period and not emit light during the light-off period in response to the light-source controlling signal.