I've been anticipating the release of practical head mounted display for years since they have tremendous potential for robot and remote telepresence applications. So far all of the designs have either been obtrusive and block the wearer's vision somehow, or they have had limitations that have precluded commercialization.
Now Brother Industries has announced they will roll out their AiRScouter transparent LCD display this Fall for business/industrial applications and hope to follow up with a commercially available version in the near future.
The basic principle utilized in Brother's design is simple and reminds me a lot of magic tricks I studied as a child. A half transparent mirror is suspended in the viewing path, in this case the left eye, and the image is bounced off the mirror and into the eye. The active electronics and LCD display itself are packaged in a small, light case that hangs on the glasses to the side. Just like the old magic tricks, the device gives the illusion of a screen appearing between the viewer and the scene they are viewing.
The AiRScouter has been in development for several years, and the company has demonstrated it at major trade shows and events as far back as 2008. This is the first time that they have actually mentioned a release date commitment, though they had previously targeted an early 2011 release date. Here's a 2010 video courtesy of DigInfo News:
The display is 800x600 pixels, high enough resolution for most applications. Since it weighs just over 100 grams it shouldn't feel very obtrusive even if users have to wear it for extended periods of time.
Remote telepresence combined with robot operation is the most exciting application I can see for this technology. There should also be tremendous use in educational environments, not just in academic settings but also in industry. Brother's plans are much more mundane and down to earth. Their vision, no doubt reinforced by a deal they just signed with NEC, is for the device to be deployed for use in parts assembly, inventory picking, and similar factory tasks.