I sent my 640 in for a repair of a bright spot, it came back with an even bigger bright spot. Wasn't happy at all. My advice is to pick up an AT&T 640 for $29 and switch out the screens. I believe it's caused by debris getting on the backlight, not a polarizer issue. This you could do yourself but there's always a chance you could screw it up messing around with it. The 640 isn't exactly vacuum sealed, and you can see what i mean when you take the back cover off and see where all the light leaks are. To prevent this I don't carry it in my front pocket anymore.