Image Sticking in LCD TVs
Image Sticking in LCD TVs
By Andrew Ghigo
Image Retention – Isn t it just an issue with Plasma TVs?
What is Image Sticking? Many are aware that if you leave a static image for a prolonged period on a plasma TV, you may risk phosphor burn-in. The result is that once you remove the static image, you would still be able to see a faint outline, or ghosting of the original image, even when you change the picture content.
LCD TVs do not suffer from burn-in, yet as surprising as it may seem, they still suffer from image retention when a static or semi-static image is left displayed on the screen for too long.
The intensity of image retention depends on various factors, not just the duration the static image remains displayed on the screen. Issues such as image makeup, operating temperature, and the LCD panel brand itself, should also be factored in.
Image retention in LCD panels is often referred in the LCD industry as image sticking . As with burn-in, image sticking is a phenomenon where a faint outline of a previously displayed fixed or semi-fixed image remains visible on the screen even when the image is changed.
It should be remarked that though burn-in in plasma televisions and image sticking in LCD display panels both result in image retention or ghosting on the display panel, yet burn-in and image sticking are two different phenomena.
What Causes Image Sticking in TFT LCD Displays?
Image sticking is an intrinsic behavior of TFT LCD panels. It is the result of their susceptibility to polarization of the liquid crystals inside the display panel when a static image remains displayed on the screen for too long. How long – depends.
This results in a parasitic charge build-up, or polarization, within individual pixels and sub-pixels. This polarization takes place at the liquid crystal level in the LCD panel it affects the crystals optical properties as it prevents the liquid crystals to return fully to their normal relaxed state upon deactivation.
Manufacturers Warranties against Image-sticking
Generally, manufactures do not warrant an LCD display device against the occurrence of image retention.
Like burn-in in phosphor-based displays, image sticking is considered by manufactures as a phenomenon that is inherent to the respective display technology. Furthermore, its occurrence is tied up to end-use and as such, the possibility of image retention is end-user dependent.
Putting things in their Right Perspective Surely, working with a retained image in the background is to say the least, extremely annoying. Besides, as expressed earlier on, except for the few, manufactures warranties would not generally cover image-sticking issues with LCD panels.
However, to put this whole discussion in the right perspective, it is important to keep in mind that the need to display a static image for more than a few minutes in home entertainment is generally non-existent.
Further more, while the best approach is to take the necessary steps to avoid image sticking in the first place, yet image sticking in LCD panels can often be reversed to a point of total invisibility.
To find out more on image sticking in LCD displays, including ways to reverse it and how best to avoid it, read the full article appearing on Practical Home Theater Guide at http://www.practical-home-theater-guide.com/image-sticking.html.
(C) 2004 – 2007 www.practical-home-theater-guide.com. All rights reserved.
Andrew Ghigo – A Telecoms/Electronics engineer by profession, with specialization in digital switching and telecoms fraud management systems a keen home theater enthusiast, with a lifelong interest in home electronics and a devoted audiophile for the last 25-yrs.
Editor and publisher of Practical Home Theater Guide [http://www.practical-home-theater-guide.com] – a comprehensive home theater guide to home theater systems, product reviews and home theater design.
This article is an excerpt from a series of informative guides appearing under the LCD TV section of the site at http://www.practical-home-theater-guide.com/LCD-Tv.html.
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