My 3ds top screen is black but my bottom screen is fine what's going on and how do I fix it

Hello I was wondering, What's happening when my 3ds XL top screen is blank (black not showing any icons) and my bottom screen is showing (like a normal 3ds XL) here's a link to my video on how it looks like: http://www.playtube.pk/watch.php?v=fJ1hpX1Tm6I4