See for example the following thread and the links contained therein:
In short: After a static image is displayed on screen for a number of minutes, after switching to a different image, the contours of the previous image remain visible, and slowly dissipate over time (also minutes). This applies also to partial images, i.e., if only a part of the image was static, that part will "burn in", while the rest won't.
At some point, after many frustrating months following the release of the machine, Mark at the Lenovo forums released a statement indicating that a newer batch of panels should have the issue greatly reduced and that Lenovo will exchange panels that exhibit noticeable persistence with new ones, under warranty. Here is the original post by Mark:
http://forums.lenovo.com/t5/X-Series-Th ... 363#M30686
There has indeed been some evidence that the later batches of the IPS panels exhibit lesser ghosting, although they are not 100% free of it. For instance, this thread:
http://forum.notebookreview.com/lenovo/ ... els-3.html
But I was hoping for something more conclusive. With many X220 IPS owners here, I hope that someone can share their personal experiences:
- Have you noticed said persistence phenomenon on later revisions of the panel?
- Have you been able to compare earlier and later revisions to say that there the effect is indeed more pronounced in the earlier ones?
http://forums.lenovo.com/t5/X-Series-Th ... ue#U543137
I guess, it might be possible that my panel was manufactured earlier. Is there a way to find out without opening up the bezel?
Without an earlier unit to compare to, I do not know if my level of persistence is to be considered normal or abnormal. I can try my best to describe what I see.
- Most comments quoted that it takes 10-15 minutes for the "burn" to appear. It is actually far far less than that. Already after 2 minutes of a static image, the retention is visible when changing images. It is of course stronger, if the image was static for a longer period. It takes it about the same time to gradually dissipate as it took to "create" it.
- I've noticed that there is a very strong correlation between the luminance of the color displayed on the new image and how visible the old image is. Notice that I'm not talking about screen brightness, but the color luminance/lightness (on the HSL scale). The retention is very visible on darker shades (seems to peak around luminance level 30-50 out of 240), and becomes less visible as the luminance increases. At luminance levels over 150 it is invisible are almost invisible. In particular I never see it when displaying the pure colors (255 in one or more of the color channels). This is how I first noticed it, because by chance, my Win8 start screen background was set to a fairly dark purple. I then investigated with Dead Pixel Buddy (which is capable of displaying a solid screen of any color), and concluded that the color itself has almost no effect on visibility of the retention. Only the luminance.
Thank you for your time reading it.