Virtual reality
Around the same time, Douglas Engelbart used computer screens both as input and output devices. In 1968, Ivan Sutherland, with the help of many students including Bob Sproull, created what was widely considered to be the first head-mounted display (HMD) system for use in immersive simulation applications. It was primitive both in terms of user interface and realism, and the HMD to be worn by the user was so heavy that it had to be suspended from the ceiling. The graphics comprising the virtual environment were simple wire-frame model rooms. The formidable appearance of the device inspired its name, The Sword of Damocles.
Optical head-mounted display
In January 2013, the Japanese company Telepathy was founded by the augmented reality entrepreneur Takahito Iguchi. At SXSW 2013 the company unveiled the Telepathy One, an eyewear display that consists of a small micro projector to create a virtual 5-inch screen that appears to float in front of the wearer's eye and a built-in micro camera. It uses an OS built off Linux and can connect to other devices via Bluetooth. It allows users to receive e-mails, check updates on social networks, and even share whatever scene the user is looking at with his friends. A Consumer version is expected to hit the US before the 2013 Christmas season.