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I’ve been reading these forums off and on for a number of years now, always when I’m thinking of buying something for my home theater. Like everyone else interested in plasma display technology, I read with interest many of the posts about image retention and burn-in. Ultimately, and after viewing many TVs and display technologies, I purchased a Panasonic plasma TV. Now, 8 years later, I couldn’t be happier.


I have never had any lasting image retention and I’m going to use this post to explain why I feel that most fears about image retention and burn-in are overblown. And I will also use this post to explain why I think that things like pixel flippers, pixel orbiters, analog snow displayed for hours on end, and the various “IR eliminators” are no better than just leaving a solid white image onscreen to eliminate any evidence of IR and/or burn-in. To me, they all seem like marketing gimmicks that serve no more function than a placebo.


Ok, let’s assume that IR and burn-in are caused by uneven phosphor brightness (i.e. different pixels have different brightness given the same voltage). Let’s also assume that phosphor brightness diminishes by the inverse exponent (which I have read is accurate), as illustrated in the following graph:




Now, let’s consider a brand new plasma which is being used to display a lot of 2.35:1 content, so that the difference in pixel age (which would be measured in something like volt-hours) between the least-used pixels (those in the black bars) and the most-used pixels (active region), is x. When the panel is new, the pixel brightness between the least and most-used pixels might span the following range (depicted on the y-axis):




Now, let’s assume the owner notices some image retention and begins to feed the panel a more uniform input, resulting in all of the pixels aging at a constant rate. The pixel-age-difference now stays the same as when the owner noticed the image retention, but now with the uniform imagery being displayed, all of the pixels begin aging uniformly. Now, the pixel brightness between the least and most-used might span the following vertical range:




Again, same difference in age between the least and most-used pixels, but since the difference in brightness is now much less pronounced, the image retention has effectively faded, or even become imperceptible.


The net result of all this is that, while it would be impossible to ever narrow the difference between the least and most-used pixels in the display (it will always either stay constant, or increase over time as we can never produce an input image that brings every pixel to the same age), the image retention will fade over time, simply due to the fact that, when one is far enough out along the x-axis on the pixel brightness graph, the brightness will be nearly the same over the span of pixel ages. This assumes that one actually tries to wear the pixels evenly – if a plasma were used to display only 2.35:1 content for thousands of hours, the display would have least-used pixels stuck at zero volt-hours, while most-used pixels continued aging, widening the pixel age span.


Finally, to bring this around to the point I was trying to make, I contend that pixel orbiters, flippers, snow, etc. are no better than a simple solid white screen at reducing or eliminating IR. For instance, let’s assume that analog snow is truly made up of pixels of random brightness. All this would serve to do is age the pixels uniformly, but with an average gray color. This would be equivalent to displaying a solid gray screen - a good way to uniformly age the pixels, but slower than an all-white screen


Sorry for the length of this post. Again, this is mostly based on my intuition and things I’ve read over the years, so please pick it apart and discuss.
 

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Your graphs illustrate what I believe - its best to get past that early period where the panel ages quickest and IR is most noticeable.

Avoiding longer periods of channels with bright white logos during that time and running full screen white shade slides or using any aging function (displays full white screen) in the service mode, at least during off hours for the first several weeks may help get past that early period quicker.
 
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