Augmented Reality and wearable headset computer monitors–sounds like a tech marriage made in electronic heaven. Until now, it’s often seemed like a clunky hardware-limited idea though. Then NTT DoCoMo arrived.

NTT, in case you haven’t heard of it, is a Japanese cell phone operator (the nation’s leading one) so it’ll be no surprise to hear that the clever AR system it’s just unveiled at the Ceatec convention is powered by a Japanese smartphone. The cleverest bit of the tech–the glasses–aren’t NTT-invented, however. They were produced in collaboration with Olympus who, as a long-time maker of cameras and other optical instruments, know quite a bit about using tech to form images.

Olympus had revealed an AR headset back in 2008, but weighing in at 91g it easily swamped and interfered with normal eyeglasses–and would’ve been trying to wear for any extended period. The new AR headset is designed for exactly that timescale, so Olympus has worked to shrink both size and mass of the display unit down to about 20g. The new device uses super-small electronics and optical light guides to get the visual picture from the display into your eyeball–appearing as a small image overlayed on the lower half of the user’s right-eye visual field. And it may actually be the first useable wearable headset monitor that looks half decent, without any similarity to Star Trek’s Geordi La Forge.

What’s it for though? It’s actually a little slice of the future, available to try out right now. Augmented reality systems, like the popular Layar app, typically use a smartphone’s camera and screen to display “augmented” information about the world as seen through the lens on the smartphone’s display. The tech is growing fast, and you may have encountered it as a tourist, where city guides and helpers for city metro systems make excellent use of the idea.

NTT’s system uses an HT-01A handset, sure, but the display is actually projected into your vision, and the headset is packed with sensors to tell the unit which way you’re looking. As a result, when you glance upwards at the sky it’s all detected and the display shows you a brief weather report. At Ceatec NTT was demonstrating a Kyoto city guide that could help navigate you around without requiring you to glance down at a handset (or hold one out in front of you, in a tempting-for-thieves kinda way).

It’s impressive, and leaves us with just two questions: First, when will NTT/Olympus turn this prototype into something really on sale? (Interim answer: They’re “discussing it”.) And second, now we’re all just getting used to seeing folks muttering into their hands-free units, how quickly will we get used to seeing people walking around goggled-into the Net?