I managed to find the Official TRON Legacy font on the New HTML5 TRON Legacy Digital Comic! It even includes all the numbers!
Its called Encom.
Heres a glace at the all the Characters, (link to font below)
I found the link for it in the source code and downloaded it from there. Go to this website URL:
and there you have it!
It only contains capital letters and the numbers. So if you use this font in a text editor or visual effects, you must have Caps Lock on or else you wont get all the letters.
If you want to read the comic then just go here.
Theres also another font in the source that I think might have been used for the End Credits also. Should I post it?