Backlight Module Variable Refresh Rate Control
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Solution Overview
Problem
Conventional LCDs with variable refresh rates face motion blur due to visual persistence, and existing solutions like black frame insertion are ineffective as they are only applicable to LCDs with fixed refresh rates, leading to inconsistent brightness perception.
Innovation Solution
A display device with a liquid crystal panel and a backlight module that adjusts its lighting based on variable refresh rates, using a control unit to manage light emission and switching between lighting and darkness to maintain consistent average brightness across different refresh rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If black frame insertion method is used to resolve motion blur, then motion blur is reduced, but the method is only applicable to LCDs with fixed refresh rate and causes inconsistent brightness perception
Solution Approach 1:
The patent applies dynamics by making the backlight module's lighting control adaptive to variable refresh rates. The control unit dynamically adjusts the lighting control signals based on the actual refresh rate of the liquid crystal panel, enabling the system to adapt to different refresh rate scenarios rather than being fixed to a single rate. This resolves the contradiction by making the motion blur reduction method versatile across different refresh rate configurations.
Solution Approach 2:
The patent changes the parameter of backlight lighting control from a fixed pattern to a variable pattern that adjusts according to refresh rate. By modifying the lighting control signals to account for variable refresh rates, the system maintains consistent average brightness while reducing motion blur. This parameter change enables the system to handle both fixed and variable refresh rate scenarios effectively.
2Object-affected harmful factors
If black frame insertion is applied to variable refresh rate LCDs, then motion blur may be reduced, but brightness consistency deteriorates due to varying refresh rates
Solution Approach 1:
The patent implements feedback by having the control unit monitor the actual refresh rate of the liquid crystal panel and adjust the backlight lighting control signals accordingly. This closed-loop control ensures that the average brightness remains consistent even when the refresh rate varies, while still achieving motion blur reduction. The feedback mechanism allows the system to compensate for brightness variations that would otherwise occur with fixed lighting control patterns.
Solution Approach 2:
The system dynamically adjusts the backlight lighting duration and intensity based on the actual refresh rate being used. This dynamic control ensures that regardless of whether the panel operates at a higher or lower refresh rate, the average brightness perceived by the viewer remains consistent, while still providing the motion blur reduction benefits of black frame insertion.
3Illumination intensity
If fixed refresh rate is used with black frame insertion, then brightness consistency is maintained, but adaptability to variable refresh rate is lost
Solution Approach 1:
The patent achieves universality by designing a backlight control system that can operate effectively with both fixed and variable refresh rates. The control unit is configured to detect the actual refresh rate and apply appropriate lighting control signals, making the system multi-functional and compatible with different display modes. This eliminates the need for separate control mechanisms for fixed and variable refresh rate scenarios.
Solution Approach 2:
The system transitions from static, fixed-rate lighting control to dynamic, adaptive lighting control that responds to the actual refresh rate. This dynamic capability enables the system to maintain brightness consistency across different operating conditions, achieving both the stability of fixed-rate systems and the flexibility of variable-rate systems.
Data Source
AI summary
An operation method of a backlight module is disclosed. The operation method includes: determining whether a first video synchronization signal is received; in response to a determination that the first video synchronization signal is received, activating a counter, and controlling the backlight module to emit light a specific number of times at a first brightness for a first time period; determining whether the counter is timeout and a second video synchronization signal is not received; and in response to a determination that the counter is timeout and the second video synchronization signal is not received, controlling the backlight module to switch between lighting and not lighting multiple times within a second time period.