Head-mounted 3D displays have promised to be the next big thing for decades. If only they weren’t so big.
But while our tech gadgets have shrunk from devices that you could lug around the office into phones and tablets that can be slipped into a pocket, head-mounted 3D displays have remained stubbornly bulky. The problem: electronics have shrunk, but optics haven’t kept pace.
Douglas Lanman, a researcher at NVIDIA, uses an array of microlenses — and some sophisticated graphics technology — to solve this problem, turning headwear that screams “geek” into something much more chic.
We debuted this approach — which Lanman is calling a near-eye light-field display — at the recent SIGGRAPH visual computing conference.
“This is virtual reality without having to wear something the size of shoe box on your head,” Lanman says.
In fact, today’s devices look a lot like the first head-mounted display created by Ivan Sutherland in 1968. To explain why, Lanman pulls out the optics in a pair of 3D glasses now on the market. While the electronics and micro-displays used in the device are vanishingly thin, the optics aren’t.
This representative device is built around optics that are each over 1.25 inches – or 33.5 mm – thick and weigh 58 grams. As a result, the whole device has to be sculpted around these bulky lenses. “This is why we’re stuck,” he says. “You want an immersive virtual reality experience, but the optics won’t let you have it.”
The solution Lanman and Senior Director of Research David Luebke came up with: more lenses. Lots more lenses. Rather than having each eye look through one big lens at an image that’s roughly an inch away, Lanman’s mockup lets users look through an array of tiny lenses at an image on an OLED panel that’s much closer.
As a result, the optics in Lanman’s prototype are just 3.3 mm thick and weigh about 0.7 grams each. That’s roughly one-tenth the size of current ones.
But size isn’t the only advantage. Because the microlenses present slightly different images to the eye, depending on how they’re positioned, images that the eyes are focused on appear sharper, mimicking the way vision works in real life.
Lanman came up with the idea of using microlenses after Frank Fox, who leads NVIDIA’s Consumer Electronics Engineering group, asked Lanman to look at ways to improve head-mounted displays using light-field technology. The assignment was a good fit for Lanman, who has a long-running interest in displays. Lanman holds a Ph.D. in electrical engineering from Brown University and spent two years at MIT’s famed Media Lab before joining NVIDIA.
The drawback to near eye light-field displays: relying on microlenses cuts down on an image’s resolution, since each tiny lens is magnifying just a small portion of a display upon which different perspectives of the same scene are rendered.
Even with today’s super dense micro-displays, the result isn’t high-definition. Yet. But that’s changing. Lanman is betting that within five years or so, higher-definition displays will be commercially available. As a result, thin, comfortable head-mounted displays may finally be a reality.