According to the filing, the device would be an "information processing apparatus" with wireless communication capabilities and the ability to read NFC and RFID chips (like those found in Nintendo's Amiibo figures), along with the integrated circuit chips most commonly seen in credit cards. The mystery device was invented by Norio Matsumura, director at Ambrella and a frequent collaborator on Pokemon games. Matsumura's involvement, along with the patent filing which lists The Pokemon Company as one of three assignees indicates that the device will have some link to Nintendo's intensely popular monster catching franchise, though here again details are sorely lacking.
While NeoGAF commenters have concluded that this patent is some kind of Pokemon gaming system, the patent filing does not offer enough information to support that idea. It could just as easily be a real-world Pokedex analogue or something completely unrelated to diminutive Japanese monsters. Only time will tell what Nintendo has in store, but while we wait, we invite you to leave your ideas on what this gadget might be in the comments below. Best response wins nothing, but your parents will be proud.