Does the iPhone 4 screen dim over time?

Maybe I’m just going crazy, maybe others have noticed it.  A couple of my friends just got new iPhone 4s, two got the white one and one got the black one.  I originally got mine last year after waiting in line for 8 hours but the one I have now is from last November I believe.

Does anyone else notice a difference in the clarity of the screen?

I decided to do a little test: I set the lock screen backgrounds at the same pre-installed picture that Apple has in the backgrounds camera roll, set at the same brightness with the auto-brightness turned off, and we both swear the new phone is brighter.

So does the screen lose it’s resolution or over time does the phone dim?

Has anyone else noticed this?  Anyone have any fixes for it?  I miss the bright clear screen my phone used to have!!