What better way to take a trip in a personal virtual reality bubble, or sit down to a private movie screening on a seemingly enormous screen, than donning a head-mounted display? Unless you happen to be dressed as Geordi La Forge at a Star Trek convention though, wearing such technology does kind of label you a bit of a geek. The Glyph headsets are a little different. In non-video mode, the device just looks like some rather bulky headphones. The headband, however, can be pulled down over the eyes for an immersive escape. Rather than looking at an LCD or OLED display (or in some cases using an actual smartphone screen) through lenses, Glyph users have the video and game images projected directly on their retinas courtesy of a combination of special optics and millions of tiny mirrors. The first pre-production prototypes are currently being assembled in readiness for CES in a few weeks, ahead of a launch on crowdfunding platform Kickstarter.
Now in the final stages of pre-production prototype development, the Glyph is based on patented technology developed by Avegant CTO Dr Allan Evans. Other key players in the company are Ed Tang (CEO), Yobie Benjamin (COO and CSO), Grant Martin (Head of Marketing and Product Strategy), and Neil Welch (VP of Engineering). Image delivery is undertaken using a combination of custom optics and micro-mirrors (similar to DLP, and developed in partnership with TI) to reflect low-powered LED light directly onto a user's retinas, which is reported to result in a more vivid, lifelike image, with a level of clarity not available on other head-mounted displays.
"We stare at things like computer screens all day, and as you know, if you look into that screen for half an hour, you get really tired," Tang told CBS Detroit last week. "But if you look at the real world, you don’t. He [Evans] set about trying to solve that, trying to recreate that really vivid, natural image. He created a virtual retinal display that replicates how we see things in the natural world, by reflected light. When you stare into something that’s glowing, like an emissive LCD panel, you get eye strain. We reflect the light – we take a low-power, low-light LED and shine it at a couple million microscopic mirrors. These mirrors bend and tilt, and we use the mirrors to control what light to reflect to your eye. That’s the core technology of what we’re working on here."
Glyph is said to offer users the equivalent of an 80-inch screen from 8 ft (2.4 m) away, currently giving users about a 45 degree field of view out front. That's about par for the movie-watching course with existing tech from the likes of Sony, but nowhere near as game-tastic as the Oculus Rift, though Avegant says that it's "actively exploring markets and applications that require higher field-of-views."
Folks who wear glasses have also been catered for with the inclusion of diopter adjustment and, refreshingly, the device has not been designed to work with specific hardware. Users can hook up the Glyph to an Xbox or Playstation, a PC or Mac, and iOS or Android device, or an optical media player via an HDMI/MHL input (DVI has been mentioned too, but won't be included in early units). The company has confirmed that a wireless version of the Glyph is on the to-do list.
The current prototypes have proved successful in head-tracking testing, so there's potential for immersive gaming, and reported system benefits include high resolution 2D or 3D viewing, absence of a screen-door effect and low latency.
"The image is very clear and refreshes at up to 120 Hz with minimal motion blur, " Banks tells Gizmag. "We are working on new techniques to remove any residual color break-up that can occur with field-sequential displays, but so far no problems there."
The Glyph doesn't just promise superior visuals, the device also packs some in-house headphones. "We will post a transfer function of our sound across 20 Hz - 20 kHz so that people can judge themselves," Evans reveals. "The drivers are 40 mm and we have already defined and tailored our own audio signature. It sounds great. Very low distortion, pretty flat response with a small bass boost. We focused on audio signature over total suppression from ANC canceling so there is no compromise there."
The final specs relating to the built-in batteries have yet to be confirmed, but the developers are aiming for 2 - 3 hours of battery life before needing to recharge via micro-USB. The company is also in the process of testing various materials to make long haul use as comfortable as possible. "The spring tension of the band on the ears will help hold up the Glyph," says Banks. "The rest of the weight will fall lightly on the users nose on a padded nosebridge."
More details will be available when the beta version of the Glyph launches on Kickstarter on January 22 (pledge levels will start at US$499), but we're hoping to catch up with the team for a hands-on of the working prototype at CES.
Until then, you can see an earlier prototype being put through its paces in the video below. The television in front of the gamer shows what's being seen through the virtual retinal display glasses.
Source: Avegant
I wonder if this technology could be used to create pseudo-holographic images using Seereal's technology (www.seereal.com) rather than steroscopic 3D. We all know that even well implemented steroscopic 3D can still cause eye strain.
Doc Rings
I did some rough calculations for a thing that would use a strip of MEMS vibrating mirrors, maybe 1080 of them, and some focussing (collimating) optics plus a trio of coloured diode lasers, highly attenuated, and came up with an effective field-of-view that should knock people's socks off. That was years ago, so I'm glad somebody's actually trying to do it!
Depending on how you positioned the lasers, you might need three rows of mirrors or the RGB wouldn't converge properly, but with semi-reflecting prisms it should be possible to have a virtual RGB laser diode with all the beams collimated identically.
If you are physically rasterizing right onto the retina, a diagram of the eye will show you that with good wrap-around collimating optics that almost touch the eye, you can reach far to the edges of the sensitive bit.