Epson has announced the Moverio BT-100: a head-mounted display (HMD) offering wearers a chance to enjoy big-screen entertainment. The further a user stares into the distance, the larger the image looks: a viewer staring at a point 20 meters away sees the equivalent of a 320-inch display. It weighs only 240 grams.

Previous displays of this type could not be worn on a bus or train confidently as wearers could not see their surroundings and could become disoriented.

Epson development specified a head-mounted display that would deliver a big-screen experience to people on the go. The solution was to make the display transparent: viewers can still see their surroundings while viewing a movie. It also had to be small, lightweight, comfortable, and provide enough battery life to be convenient when travelling.

Light projected through a panel, travels through a sheet-like light guide. It bounces off a half mirror into the wearer's eyes. Projected light is balanced against the intensity of that from outside, so users can see their surroundings and the images from the LCD panel in the same field of vision.

The light guide is made using injection molding. This required a precision that was achieved using the same high-precision molding technologies as in the manufacture of Epson's inkjet printers and 3LCD projectors. To achieve the see-through display, the light guide has to be accurately bonded to the frame's rim and hard coated like eyeglass lenses. Strong springs for the thinner side arms firmly clamp the wearer's head to keep the unit in place which makes the unit more comfortable in use. By optimizing power management -- not suppling power to components that are not in use, and using carefully designed cables -- Epson was able to achieve 6 hours of battery life.

More information and some useful links are available on the Epson web site.