LCD Panel Variable Common Voltage for Flicker Reduction
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Solution Overview
Problem
LCD panels experience flickers and larger luminance differences due to leakage currents during vertical blanking intervals, especially when switching between different refresh rates, affecting display quality and compliance with dynamic refresh rate techniques like FreeSync.
Innovation Solution
The LCD panel provides a fixed common voltage to a first electrode plate in fixed refresh rate mode and a variable common voltage in variable refresh rate mode, with the variable voltage being greater than the fixed voltage when the refresh rate is lower, to mitigate the low voltage issues of the pixel electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed common voltage is provided to the first electrode plate during vertical blanking interval, then the circuit design is simple, but the pixel electrode voltage becomes lower causing flickers and luminance differences
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed common voltage to a variable common voltage that dynamically adjusts based on refresh rate. The common voltage is modified during vertical blanking intervals to compensate for leakage currents, ensuring stable pixel electrode voltage across different refresh rates while maintaining display quality in FreeSync mode.
2Productivity
If the refresh rate is dynamically adjusted to match graphic card output, then picture fluency is improved, but leakage currents cause voltage level drops and display artifacts
Solution Approach 1:
The patent applies preliminary anti-action by proactively compensating for the harmful effects of leakage currents before they cause display artifacts. During vertical blanking intervals, the common voltage is adjusted in advance to counteract the voltage drop that would otherwise occur, preventing flickers and luminance differences before they manifest.
3Reliability
If a variable common voltage is provided to compensate for leakage currents, then display quality is improved, but the control system complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the common voltage parameter based on refresh rate conditions. The voltage level is adjusted according to whether the display is operating in fixed or variable refresh rate mode, allowing quality improvement through parameter adaptation rather than fundamental system redesign.
Data Source
AI summary
An LCD panel, a driving method and a display device are provided. The LCD panel includes a fixed refresh rate mode or a dynamic refresh rate mode. In response to the variable refresh rate, the LCD panel provides a variable common voltage to the first electrode plate of the storage capacitor, thereby dynamically improving or eliminating the issues of the low voltage of the pixel electrode.