Source Driver Inversion Control for Liquid Crystal Image Retention
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Solution Overview
Problem
Existing display apparatuses using liquid crystal panels face challenges in efficiently managing inversion modes to prevent image retention and improve display quality, particularly in alternating between normal and inversion polarities for subpixels.
Innovation Solution
A display apparatus with a source driver that includes a digital-to-analog converter, multiplexers, and an inversion controller to output image signals of normal and inversion polarities, allowing operation in various inversion modes based on control signals to optimize image display on liquid crystal panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid crystal panel uses inversion modes to prevent image retention, then display quality is improved, but device complexity increases due to the need for multiple multiplexers and control circuits
Solution Approach 1:
The liquid crystal panel is divided into multiple regions (first region with first polarity, second region with second polarity) that can be independently controlled. The driver circuit is segmented into multiple multiplexers (first multiplexer, second multiplexer) that can independently select between normal and inversion drive modes for different regions, allowing targeted inversion control without affecting the entire panel.
Solution Approach 2:
The driver circuit dynamically switches between different inversion modes (first inversion mode, second inversion mode) based on display content requirements. The multiplexers can change their configuration between frames to alternately apply inversion drive to different regions, enabling adaptive control that responds to changing display conditions.
2Reliability
If inversion modes are applied to all subpixels, then image retention is reduced, but display quality may deteriorate due to unnecessary inversion of subpixels that do not require it
Solution Approach 1:
Different regions of the panel receive different drive modes based on their specific requirements. The first region may receive inversion drive while the second region receives normal drive, or vice versa, depending on the display content. This localized control ensures that inversion is applied only where necessary to prevent image retention, while preserving display quality in regions where inversion is not needed.
Solution Approach 2:
The drive mode parameter (normal or inversion) is changed dynamically for different regions and different frames. The system can switch between first inversion mode and second inversion mode, where each mode applies inversion to different regions. This parameter variation allows optimization of both image retention prevention and display quality by adapting the inversion application to specific display conditions.
Data Source
AI summary
A display apparatus includes a liquid crystal panel; and a source driver configured to output an image signal to the liquid crystal panel. The source driver may include a digital-to-analog converter (DA converter) configured to convert digital image data into an image signal of normal polarity and an image signal of inversion polarity; a plurality of multiplexers each of which receives the image signal of the normal polarity and the image signal of the inversion polarity from the DA converter, and outputs the image signal of the normal polarity and the image signal of the inversion polarity as they are or cross outputs the image signal of the normal polarity and the image signal of the inversion polarity; and an inversion controller configured to output a control signal to each of the plurality of multiplexers through a plurality of output terminals respectively connected to the plurality of multiplexers. Each of the plurality of multiplexers may be configured to output the image signal of the normal polarity and the image signal of the inversion polarity as they are in response to a first control signal of the inversion controller, and to cross output the image signal of the normal polarity and the image signal of the inversion polarity in response to a second control signal of the inversion controller.