LCD Timing Controller Weak Pattern Detection
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Solution Overview
Problem
Liquid crystal displays (LCDs) driven in an inversion scheme can experience decreased picture quality due to unbalanced polarity of data voltages, leading to flicker or smear in images, especially when dealing with weak patterns where either positive or negative polarity dominates, causing a shift in the common voltage and reference potential.
Innovation Solution
A liquid crystal display system that includes a timing controller to detect weak patterns in digital video data, adjust the logic inversion cycle of polarity control signals, and change the position of added FRC correction values to balance data voltages, thereby preventing picture quality degradation by modifying the polarity inversion cycles of data voltages supplied to the liquid crystal cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liquid crystal display is driven in an inversion scheme with fixed polarity inversion cycles, then the liquid crystal deterioration is prevented, but the picture quality decreases due to unbalanced polarity causing common voltage shift and flicker
Solution Approach 1:
The patent implements dynamic polarity inversion cycle adjustment by detecting weak patterns in input data and adapting the inversion cycle accordingly. The system transitions from a fixed inversion scheme to a dynamic one where the polarity inversion timing is adjusted based on the detected data pattern, allowing optimal picture quality while maintaining liquid crystal protection
Solution Approach 2:
The patent employs feedback mechanisms where the timing controller detects weak patterns from the input data and uses this information to adjust the polarity inversion cycle. This closed-loop approach allows the system to respond to actual display conditions and optimize performance by preventing common voltage shift and flicker in weak pattern scenarios
2Object-affected harmful factors
If the polarity inversion cycle is adjusted to prevent common voltage shift, then picture quality improves, but the complexity of the control system increases
Solution Approach 1:
The patent performs preliminary detection of weak patterns in the input data before displaying. By identifying problematic patterns early in the data processing stage, the system can preemptively adjust the polarity inversion cycle to prevent picture quality degradation, rather than reacting to symptoms after they occur
Solution Approach 2:
The patent changes the timing parameters of the polarity inversion control based on detected weak patterns. By adjusting the inversion cycle timing dynamically, the system optimizes picture quality for different data patterns without requiring fundamental changes to the display architecture or control system design
3Device complexity
If data voltages are applied with fixed polarity patterns, then the data driving circuit operation is simplified, but the common voltage shifts and reference potential fluctuates causing flicker
Solution Approach 1:
The patent implements dynamic adjustment of polarity inversion timing in response to detected weak patterns. This dynamic approach allows the system to maintain simple data driving circuit operation for most cases while adapting the inversion cycle to prevent common voltage instability when weak patterns are detected
Solution Approach 2:
The patent applies preliminary anti-action by detecting weak patterns and adjusting the polarity inversion cycle before common voltage shift can occur. This preventive measure counteracts the potential instability caused by unbalanced polarity charging, maintaining reference potential stability without complicating the overall system operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively maintains balanced polarity inversion cycles, preventing flicker and smear in images, especially for weak patterns, and reduces the number of output channels required in the data driving circuit while expanding gray levels beyond input data bit numbers.
Implementation Method 1
Liquid crystal cells of a liquid crystal display picture images by changing transmittance according to a potential difference between a data voltage supplied to a pixel electrode and a common voltage supplied to a common electrode
Data Source
AI summary
A liquid crystal display is provided. The liquid crystal display includes a liquid crystal display panel, a data driving circuit for converting digital video data into positive/negative data voltages to be supplied to the data lines and adjusting the horizontal polarity inversion cycle of the positive/negative data voltages, and a timing controller for generating the vertical polarity control signal and the horizontal polarity control signal, adding a FRC correction value to input digital video data to supply the input digital video data to the data driving circuit, detecting a predetermined weak pattern from the input digital video data and, when data having the weak pattern is detected, changing either the logic inversion cycle of the vertical polarity control signal or the logic of the horizontal polarity control signal and changing the position of the data to which the FRC correction value is added.