Liquid Crystal Display Phase Inversion Drive Flicker Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices using phase inversion drive face issues with image persistence and flicker, particularly when displaying images with constant luminance, which degrade display quality.
Innovation Solution
The implementation of a liquid crystal display device that performs phase inversion drive with a source driver outputting a second data voltage closer to the common voltage in the initial periods of a horizontal scanning frame, followed by the first data voltage, while also incorporating column or row line inversion drives, and short-circuit processing to alternately short-circuit data lines with different polarities, thereby preventing image persistence and flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase inversion drive is performed to prevent image persistence, then image persistence is suppressed, but luminance increases causing flicker that degrades display quality
Solution Approach 1:
The horizontal scanning period is segmented into two distinct periods: a first period where the data line is short-circuited to prevent luminance increase, and a second period where normal data voltage is applied. This temporal segmentation allows the system to avoid flicker during the critical initial phase while maintaining normal operation thereafter, thus resolving the contradiction between preventing image persistence and avoiding luminance-induced flicker.
Solution Approach 2:
The short-circuiting of the data line is performed as a preliminary action at the beginning of the horizontal scanning period, before the data voltage is applied. This preliminary short-circuiting prevents the accumulation of charge that would otherwise cause luminance increase and flicker, allowing subsequent normal operation without display quality degradation.
2Reliability
If frame inversion drive is performed with alternating positive and negative polarity data voltages, then image persistence is prevented, but DC current is applied to liquid crystal degrading display quality
Solution Approach 1:
The system employs periodic phase inversion of the data voltage polarity in conjunction with periodic short-circuiting at the beginning of each horizontal scanning period. This periodic action pattern ensures that DC current is prevented from being applied to the liquid crystal while maintaining the benefits of frame inversion drive for preventing image persistence.
3Speed
If data voltage is applied immediately at the start of horizontal scanning period, then display response is fast, but luminance increases generating flicker
Solution Approach 1:
The horizontal scanning period is divided into a first period for short-circuiting and a second period for normal data voltage application. This segmentation delays the actual data voltage application slightly, prioritizing luminance stability over minimal response time, thus preventing flicker while maintaining acceptable display performance.
Solution Approach 2:
The data line is short-circuited in advance at the beginning of the horizontal scanning period to prevent the conditions that would lead to luminance increase and flicker. This preliminary anti-action counteracts the potential harmful effect before it can occur, ensuring stable luminance during the subsequent data voltage application.
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
This configuration effectively suppresses the degradation of display quality and prevents image persistence while minimizing luminance increases that cause flicker, improving the overall display performance.
Implementation Method 1
an electric field generated between a pixel electrode and a common electrode is applied to liquid crystal to drive the liquid crystal, whereby a quantity of light transmitted through an area between the pixel electrode and the common electrode is adjusted to display an image
Data Source
AI summary
A liquid crystal display device that performs phase inversion drive in which a phase of a polarity of a data voltage is inverted in predetermined timing while performing frame inversion drive in which a positive-polarity data voltage and a negative-polarity data voltage are alternately output to a data line in each one or plurality of frames. In a first frame immediately after the phase is inverted, the source driver outputs a second data voltage to the data line in initial first periods of a horizontal scanning period, the second data voltage being closer to the common voltage than a first data voltage corresponding to input image data, and outputs the first data voltage to the data line in a second period after the first period in the horizontal scanning period.