TechCrunch describes it as "a way to create backlit micro-perforated holes on the aluminum casing of a MacBook or other device which could be used for buttons on the lid when the laptop is closed or below the keyboard when it is open. The buttons could serve as simple displays for WiFi signal or battery strength, control playlists and volume for iTunes songs or movies, or even replace the trackpad."
And it quotes AppleInsider's description as follows:
The input appears invisible to the user because it would be made of the same material as the housing it is contained in. The use of “invisible” backlit holes could make the input selectively visible or invisible for the user.
One illustration included with the application shows an iPod-like control wheel located to the left of the notebook’s trackpad. Such controls could be displayed with the touch of a finger, and then disappear when they are not in use — such as when a user’s wrist is resting in that area for typing on the keyboard.Not a bad concept. Sort of like the disappearing dashboard display on high-end cars like the version demonstrated by Visteon last year.