The Oculus Rift is a VR HMD being developed by Oculus VR. The high profile company raised $16 million (partly by crowdfunding) and already offer "development kits" HMDs. Their consumer version (Oculus CV) will hopefully be released in 2014 and will feature improved components, for example a Full-HD display. The current versions use LCD displays (7" in size, although early prototypes used 5.6").
Yesterday, at Oculus' development forums, a new discussion suggested that Oculus aims to adopt an OLED display in the Oculus CV. They quote Oculus CEO Brandon Iribe as saying that the need a much faster display than the current one, and that OLED was the technology that could achieve that.
In addition, the company's CTO, John Carmack, was also suggesting to developers to use green text to get full resolution in a pentile screen, which seems to confirm the company will adopt a Samsung-made OLED display (which isn't a big surprise, really).