February 22, 2008 by Dennis BarkerPlasma TVs have been around now for several years now. They were the original flat-panel display designed for hanging on the wall or over the fireplace. From the beginning, they were the darling television of interior designers. In fact, the plasma has always had a certain cache, mystery, myth about it. In some ways, they represented the future with their “floating” appearance, which culled up visions of H.G. Wells’ prophetic novel “Things to Come.” Or maybe, it simply conjured up thoughts of Capt. Kirk on the bridge of the StarShip Enterprise looking at that large wall-hanging display. Right or wrong, many consumers still believe that plasmas are superior to other types of TVs – possibly because they have a specialized gas encased inside the display and they still seem somewhat exotic. In any case, they are certainly a marvel of creativity and engineering.
The perceived problem with plasma, however, is something called “burn-in” or more technically called “image retention.” This means that if you keep an image “frozen” on the screen too long, a ghost of the image will stay with the display forever. A good example of things that could leave permanent images on the screen could be news or stock tickers, or station logos or icons – sometimes called “bugs.” In the beginning, this was certainly an issue. Now, several years later, all of the leading manufacturers of plasma TVs – Panasonic, LG, Samsung, Pioneer, and Hitachi – have all taken several steps to greatly reduce or eliminate completely any signs of image retention.
According to Jim Palumbo, President of the Plasma Display Coalition (PDC), “New plasma advancements in cell structure and phosphor formulations have virtually eliminated image retention, also known as ghosting. Tests verify that any residual ghosting generally disappeared with normal use after a relatively short time. If you haven’t burned images into your CRT television, there is little chance that you will with plasma. As with any electronic product, you should follow the usage guidelines in your owner’s manual.” Basically the PDC position is that image retention (burn-in) has been virtually eliminated and is no longer an issue.
Tim Alessi, Director of Product Development at LG Electronics, explains that “LG has gone to great lengths to eliminate uneven aging. As far as LG is concerned, it’s a non-issue today. All of our plasma sets offer an image sticking mode in case “paused” images were left on the screen for too long. As well, each set includes three other functions that further help reduce or eliminate “burn-in.” All sets include an orbiter feature that constantly shifts images by 1 to 2 pixels at a time. Secondly, there is an inversion mode; and lastly, there is a whitewash mode. Via the on-screen menus, the consumer can invoke the whitewash mode that completely turns the screen image white for between 5 -10 seconds to eliminate any images that have been retained.”
Samsung offers similar options to consumers with its Plasma HDTVs, which are available via the on-screen menu of their current 2007 models. These modes include: Pixel Shift - Adjustable image shift; slowly shifts the image up and down and/or side to side to keep the pixels from burning in. User can adjust the amount of shift, the direction and the timing, up to 4 pixels horizontally and/or vertically, taking up to 2 minutes to make a complete shift and back; White - displays a white screen to alleviate image retention and/or burn-in; Scrolling - displays a gray ramp (image that ramps from black on one side of the screen to white on the other), that then rolls across the screen, horizontally; and, Side bars- adds gray side bars to 4:3 images.
Additionally, according to Mike Wood, TV Test Manager for Samsung QA Labs America, “For reference, there is a difference between “image retention” and “burn-in.” When used correctly, the former term refers to an image that stays on screen long after the original image is gone, but that doesn’t mean the plasma or the phosphors are permanently “burned.” It just means the pixel is kind of stuck (though not usually stuck in the original state, nor in the generally considered usage of the term- it’s more of a lag) and will revert back to its “newish” state with a new signal (usually a white signal, or at least something brighter than the original signal that got it stuck in the first place), or time. One would really have to use them with a static image for a really long time (think: digital signage) to see any “burn-in” with current sets. Studies show the same is true of LCD.”
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