Note: there is no picture attached to your thread.
Well, it is 'possible' that your laptop already has a keyboard backlight ability. Many, but not all, of the HDX16s do.
To test it out press try this: hold the Fn key and press spacebar once. (That is the on/of switch for the backlight on the keyboard.)
You can also look in the manual for the computer. If you don't have one, you can find it here...
http://www.manualslib.com/manual/72066/Hp-Hdx-16.html