Liquid Crystal Display Polarity Inversion for Low Refresh Rate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices experience deteriorated display quality due to accumulation of the same source output polarity for three or more frames when the low refresh rate (LRR) technique is applied without considering source output polarities, leading to increased power consumption and reduced image quality.
Innovation Solution
A liquid crystal display device and driving method that incorporate an LRR controller to manage source output polarities using specific inversion patterns, changing them according to the LRR technique to prevent accumulation, by controlling polarities with a third inversion pattern during LRR frames and a fourth inversion pattern after the LRR operation ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If low refresh rate (LRR) technique is applied to reduce power consumption, then power consumption is reduced, but the same source output polarity accumulates for three or more frames causing display quality deterioration
Solution Approach 1:
The patent implements dynamic polarity inversion patterns that adapt based on the refresh rate mode. During LRR operation, the system dynamically switches to a third inversion pattern that ensures polarity alternation even when frames are skipped, preventing accumulation of the same polarity for three or more frames. This dynamic adaptation resolves the contradiction by maintaining display quality through active polarity management while preserving the power consumption benefits of LRR.
Solution Approach 2:
The patent changes the polarity inversion parameters based on the operating mode. It stores different inversion patterns (first pattern for normal refresh, second pattern for LRR) and switches between them. By modifying the polarity inversion parameter from a fixed pattern to a conditional pattern that changes with refresh rate, the system prevents polarity accumulation during LRR while maintaining power efficiency.
2Reliability
If polarity inversion technique is used to prevent display quality deterioration, then display quality is maintained, but device complexity increases due to multiple inversion patterns and control mechanisms
Solution Approach 1:
The patent segments the polarity inversion control into distinct modes with dedicated patterns. It divides the operation into normal refresh mode (using first inversion pattern) and LRR mode (using second inversion pattern), with each segment having its own optimized polarity management strategy. This segmentation simplifies the control logic within each mode while maintaining overall display quality across different operating conditions.
Solution Approach 2:
The patent introduces an LRR controller as an intermediary component that manages the switching between different inversion patterns. This dedicated controller acts as a mediator between the display panel and the polarity inversion logic, coordinating the use of first, second, and third inversion patterns based on the current refresh rate mode. The intermediary simplifies the overall control architecture by centralizing the polarity management function.
Data Source
AI summary
A liquid crystal display device comprises a memory configured to store polarities of the source outputs from a source driver with respect to a panel self-refresh operation and a normal refresh operation that is not the panel self-refresh operation as a first inversion pattern and to store the polarities of source outputs with respect to a low refresh rate operation as a second inversion pattern; and an LRR controller configured to control the polarities of the source outputs with the first inversion pattern in panel self-refresh frames before the low refresh rate operation is performed, to control the polarities of the source outputs with a third inversion pattern referring to the first inversion pattern in low refresh rate frames in which the low refresh rate operation is performed, and to control the polarities of the source outputs with a fourth inversion pattern referring to the second inversion pattern in normal refresh frames after the low refresh rate operation ends.