It has been revealed that Sony are preparing for an announcement of a new piece of hardware for the Playstation 4 during the upcoming Tokyo Game Show Conferences. It is rumored that this peripheral is a head-mounted virtual reality display, which was supposed to be revealed during Gamescom. Sony already entered the head mounted 3D viewer market with the HMZ back in 2011, and with the buzz created by the crowd funded Oculus Rift, it doesn't come as a surprise that either Microsoft or Sony would come up with their own variation. Oculus Rift founder has praised the rumor and said that if this news was true, developers would create more games compatible with virtual reality peripherals.
SCE have failed to comment on the rumors, so I guess we'll get confirmation during Sony's Press conference.