Screen Not Actually Fit To The Screen Size?

Has anyone else noticed that the "usable" portion of the screen, the part that lights up/displays images, is not actually using the full screen size? It's super noticeable out in the sun when you can see the boarder around it. There are probably 4-6 lines around each side that aren't "on". It looks like 6 on the bottom and 3 or 4 on the top/sides. Anyone know why the screen wouldn't actually use the entire screen? It's not a huge deal, not really noticeable unless your in the sunlight and see that there is clearly an unused "boarder" around the screen, but I just think it's a little odd, almost like on a TV that needs calibration to center the image. I have a 3GS by the way, if that makes a difference.