Widescreen TV aspect ratio is 16:9, as stated, that's around 1.8:1. Anything over that will have black bars...many widescreen movies have an aspect ratio of 2.35:1.
Aspect ratio refers to the proportion between the length and height of the screen.
As stated by Philander, anything over 1.85:1 will have black bars on the top and bottom. Anything below that, will have black bars on the side.
The aspect ratio is printed on the case (but not all) DVD. Try different DVDs. Most new TV series will have an aspect ratio of 1.8:1, and thus, fill your screen. Check it out.
Note that movies are differring aspect ratio, some like Ben Hur are extra wide (to showcase the panoramic epic), so those will have big black bars on top and bottom.
And we are not talking Letterbox widescreen. That's good for another day, or try Google...
And please...don't post multiple threads...