3g display problem

Hi there, yesterday i bought new iPhone 3G after my 2G.
I noticed one thing on screen and i'm interested if there is any hardware problem.

i can't notice anything when i'm working, its only noticable when its connected for charging, there are something like circles around battery charging indicator. It looks like as problem in gradation of white and black.

here you can see how il looks. http://img44.imageshack.us/i/dsc00002.png/