Polarity Inversion Control for LCD Frame Rate Adaptation
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Solution Overview
Problem
Liquid crystal display devices face issues with frame rate synchronization, leading to phenomena like jerkiness, frame tearing, and time lag, and existing solutions either increase component count and cost or consume more power.
Innovation Solution
A polarity inversion control device that applies pixel voltages with different frame periods and inverts polarity levels dynamically, using a polarity inversion signal with two levels to ensure equivalent application times for positive and negative polarities, thereby maintaining stable charging polarity without additional memory or double-speed inversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dynamic fps change is implemented to match input frame rates, then adaptability to different input signals is improved, but charging polarity deviation occurs due to varying charging times
Solution Approach 1:
The patent implements dynamic frame rate adaptation by allowing the liquid crystal display to operate at different frame rates (e.g., 60Hz, 120Hz, 240Hz) based on the input signal characteristics. The frame rate is adjusted dynamically through control circuits that detect input signal properties and modify the driving frequency accordingly, enabling the display to adapt to various input sources while maintaining proper polarity inversion control at each frame rate.
Solution Approach 2:
The patent changes the polarity inversion control strategy based on frame rate parameters. At different frame rates, the polarity inversion is synchronized with the specific frame timing to ensure that the cumulative charging time for positive and negative polarities remains balanced. This parameter-based control adjusts the polarity inversion timing and frequency to match the operational frame rate, preventing charging polarity deviation even as the frame rate changes dynamically.
2Reliability
If polarity inversion is performed at double speed to prevent ghosting, then display quality is improved, but power consumption increases
Solution Approach 1:
Instead of always performing polarity inversion at double the frame rate (excessive action), the patent applies polarity inversion selectively based on the current frame rate and timing requirements. The system performs polarity inversion at appropriate intervals that are sufficient to prevent ghosting artifacts but not excessively frequent, thereby avoiding unnecessary power consumption. This partial action approach adjusts the inversion frequency to match the minimum required for display quality.
Solution Approach 2:
The patent dynamically adjusts the polarity inversion parameters based on the operating frame rate. At higher frame rates, the polarity inversion timing and frequency are optimized to match the faster refresh cycles, preventing the need for constant double-speed inversion. This parameter adaptation ensures that polarity inversion occurs at the minimum necessary rate to maintain display quality, thereby reducing power consumption compared to fixed double-speed inversion.
3Stability of the object's composition
If frame rate is fixed at 60Hz, then stability of display operation is improved, but adaptability to variable fps input signals deteriorates
Solution Approach 1:
The patent implements a dynamic frame rate control system that can operate at multiple frame rates (60Hz, 120Hz, 240Hz) based on the input signal characteristics. The display controller detects properties of the input signal and dynamically adjusts the frame rate to match, allowing the system to maintain stable operation at the appropriate rate for each input source rather than being locked to a fixed 60Hz rate.
Solution Approach 2:
The patent creates a universal display system that can handle multiple frame rate inputs through a single adaptive control mechanism. The display controller is designed to universally accept various frame rates and automatically configure the internal timing and polarity inversion control to match the detected input rate, eliminating the need for separate fixed-rate control circuits for different frame rates.
Data Source
AI summary
To provide a liquid crystal display device and the like capable of achieving a function with which the charging polarity for the liquid crystal panel is not deviated even when the frame rate for writing to the liquid crystal panel changes dynamically only with simple structures and low power consumption. A polarity inversion control circuit is for supplying polarity inversion signals to the liquid crystal panel, and it is characterized to switch the levels of the polarity inversion signals in such a manner that a difference between an integrated value of frame periods when the polarity inversion signal is in a first level and an integrated value of the frame periods when the polarity inversion signal is in a second level becomes small.