Interesting. It doesn't work on my Win10. Maybe it's just my config then.I do use F6. And I use Windows 10, but anti-aliasing is indeed present.
Anyway, it's handled by the OS (or more exactly, a specific DLL and apparently a specific graphic configuration somewhere else) so I'm not sure you can enable/disable it from the Ruby script alone.
Does the traditional Alt-Enter full screen mode do the same thing?