Enjoying Visual Content Anytime, Anywhere: The Moverio BT-100 Mobile Viewer

The Moverio BT-100 is a head-mounted display (HMD) that offers wearers a chance to enjoy big-screen entertainment*1 on the go. Weighing only 240 grams*2, this compact product is the world's first product of its kind*3 and is packed full of Epson technologies.

Big-Screen Entertainment on the Go

Consumer HMDs of the past were completely immersive, isolating wearers both visually and auditorily from their surroundings and making them unsuitable for mobile applications. They could not been comfortably worn while riding a train, for example, as the wearer could not see or hear his or her surroundings and would likely feel uneasy about missing the next stop and so forth.

Development work on the Moverio BT-100 began at the end of 2009. The objective was to come up with a head-mounted display that would deliver a big-screen experience to people on the go. For this reason, (1) the display had to be transparent, so that viewers could see their surroundings while watching multimedia content; and (2) the unit had to be small, lightweight, comfortable, and provide long enough battery life to be convenient for travelers.

Visual content can be enjoyed on a see-through screen

How images are projected on a see-through display

The picture above illustrates how images are viewed on the BT-100's transparent display screens. An HTPS panel is mounted in the frame, within the side arm (the part near the temples). Light projected through this panel travels through a sheet-like light guide and eventually bounces off a half mirror and into the eyes of the wearer. Deposition technology is used to create the half mirrors, which reflect some light while transmitting the rest. The projected light is balanced against the intensity of light from the outside world so that the wearer can see his or her surroundings and images from the LCD panel in the same field of vision.

How images can be viewed on a transparent display

Combining Epson technologies

The biggest challenge for the developers of the Moverio BT-100 lay in constructing the light guide. Manufacturing the light guide using injection molding required extreme precision and was achieved using high-precision molding technologies acquired in the manufacture of Epson's inkjet printers and 3LCD projectors. In addition, to achieve the see-through display, the light guide has to be accurately bonded to the frame's rim and then hard coated just like eyeglass lenses.

Six-hours of battery life

The BT-100 was developed with travellers in mind, making battery life an important consideration. The problem is that you have to trade-off some battery life for each function. For example, if you want to make an image brighter, you have to sacrifice some battery life. Epson was able to achieve six-hours of battery life by optimizing power management. Among other things, this entailed not supplying power to functions that are not in use. The cable that connects the headset and controller employs a low-power communications standard. The cable itself was also modified. The 32 wires that make up the cable were twisted in a manner that makes the cable thin (3.7 mm in diameter) and pliant, thus relieving cable stress.

Wearer comfort maximized

Comfort is another key consideration for devices that are worn for extended periods of time. The Moverio was made more comfortable by paring the thickness of components to make the frame lighter yet without compromising strength. It was also made more comfortable by using strong springs for the side arms so that they firmly clamp the wearer's head and keep the unit in place. To prevent discomfort from an overly tight fit, the design team added cushions on the inside of the earpieces.
This HMD unit also comes with three different sizes of nose pads, for a more custom fit.

Cushion on the inside of the earpiece

Going forward, Epson intends to capitalize on the value that hands-free, see-through HMDs have to offer, not only in consumer applications but in business applications.

*1 The farther the user stares into the distance the larger the image looks. (For example, a viewer staring at a point 20 meters away would be perceived as the equivalent of a 320-inch display.)
*2 Headset only
*3 According to Epson research the Moverio BT-100 is the world's first standalone see-through consumer head mounted display (as of November 25, 2011).

Read the news release
Epson Unveils First Consumer See-Through Mobile Viewer Making Big-Screen Multimedia Entertainment Accessible on the Go

Please refer to your local Epson site for details of these and other Epson products.
(Note that product names and availability vary by region.)