Optical head-mounted display

An optical head-mounted display (OHMD) is a wearable device that has the capability of reflecting projected images as well as allowing the user to see through it, similar to augmented reality technology. Various techniques have existed for see-through HMDs. Most of these techniques can be summarized into two main families: 'Curved Mirror' (or Curved Combiner) based and 'Waveguide' or 'Light-guide' based. The curved mirror technique has been used by Vuzix in their Star 1200 product, by Olympus, and by Laster Technologies. Various waveguide techniques have existed for some time. These techniques include diffraction optics, holographic optics, polarized optics, and reflective optics: Augmented reality systems guru Karl Guttag compared the optics of diffractive waveguides against the competing technology, reflective waveguides. Head-mounted displays are not designed to be workstations, and traditional input devices such as keyboards do not support the concept of smart glasses. Input devices that lend themselves to mobility and/or hands-free use are good candidates, for example: In June 1995, MicroOptical was founded by Dr. Mark Spitzer to develop advanced micro-optical devices reduced to the size of integrated circuits. The company was funded by the Defense Advanced Research Projects Agency through a contract with the U.S. Army Soldier Systems Command for the development of optical micro-electromechanical systems (MEMS). In 1997, MicroOptical demonstrated the eyewear display in which the viewing optics were incorporated in the eyeglass lens. The eyeglasses display provided a 320x240 pixel resolution with 8 bit greyscale and a field of view of approximately 8 degrees (horizontal). On 16 June 2003, MicroOptical announced the availability of the SV-6 PC Viewer, the first eyewear-mounted display specifically designed for use with mobile personal computers. It was small, ultra-lightweight and highly ergonomic and could connect to mobile computing devices via a VGA output. Its initial price tag was US$1995. In March 2007, MicroOptical changed its name to MyVu and at CES 2008 it demonstrated the Crystal 701, video eyewear which lets the user watch a large virtual screen from 6 feet away and It featured MyVu's patented SolidOptex® optical system, a VGA (640x480) resolution, a cables that allow the user to connect it to MP4 players, DVD players, camcorders, or gaming systems with composite video output and a battery that provides up to 4 hours of video viewing. In May 2008, the Crystal was launched at Amazon and Best Buy with the price tag of $300. However, the company did not survive the 2008 recession, and in 2010 it was dissolved. Its assets, including patents, were sold to Foxconn which then formed subsidiary View Link Technology in Singapore, with the mission to establish a new line of wearable near-eye systems for industrial, medical, and consumer use. In August 2012, Mark Spitzer, formerly a principal scientist at Kopin Corporation and the founder and CEO of MicroOptical/MyVu, was hired by Google as a Director of Operations at Google X. In April 2013, Google acquired several of MicroOptical/MyVu patents from Foxconn, who is in contract with Google to manufacture the Google Glass in Santa Clara, California. In 1997, Sony released the Glasstron, an HMD which included two LCD screens and two earphones for video and audio respectively. It also had a mechanical shutter to allow the display to become see through