i had been playing on my ds for weeks, never noticed, until today i tilted the console and noticed screens got a dark somewhat round area in the center if i am looking at the screen from the correct position i can't see it at all, only can see it tilted the screen is cleaned, my first thought was to clean it.. but didnt helped... so what can this be? is the screens dying? or just humidity? should i try to regulate the screen "regulators"? click picture for zoom, was too large..