A problem I notice on many TV's

[MRX37]

Sometimes, especally if there are bright areas in the picture, a TV's picture will distort a bit. The best example of this is straight bars that end up curving a bit when the picture gets brighter.

The 25" Samsung TV I found awhile back does this. It kinda annoys me as I've been using it as a computer monitor. When a window pops up, the sides of it are curved inwards, making it look slightly trapezoidal like.

I notice many TV's that do this, so I'm wondering if it's an actual problem, or just a characteristic of the design? I know TV's aren't designed as good as computer monitors are...