Demo of Prototype Virtual Retinal Head Mounted Display 93
muterobert writes with an article about a new head mounted virtual retinal display (technology last covered ages ago). The folks over at Road to VR took a look at an engineering prototype; from the article: "The Avegant HMD uses a virtual retinal projection display consisting of a single LED light source and an array of micro-mirrors. This differs from normal screens in that with a VRD there is no actual screen to look at. Instead, a virtual image (in the optical sense) is drawn directly onto your retina. . ... 'At one point I was looking at a sea turtle in shallow coral waters. Sunlight was beaming down from the surface and illuminating the turtle's shell in a spectacular way — it was one of the most vivid and natural things I've ever seen on any display. The scene before me looked incredibly real, even though the field of view is not at immersive levels.'"
pretty epic (Score:5, Insightful)
It's not "direct-to-eye" - There's a screen. (Score:2, Insightful)
It's the micromirror device. Duh. There is no fundamental optical difference between this, Google Glass, and Oculus Rift. The only differences are the size of the physical component that is the screen (very small in the case of Glass, medium in this case, much larger in the case of Oculus Rift) and the optics used for the light path (from trivial in the Rift to more complex in this case and in Glass) and thus also the apparent size of the screen to the wearer.
Retinal "projection" is just a fancy term for "making it look to your eye like there's a screen in front of it". There's no magic. Even with a scanning laser-based retinal projection system, where there is no physical screen (but a scanned laser creates a virtual plane that acts like one) you still need to cover the eye in a big lens and make the light seem to come from the same places it would come if there were a big screen in front of it. It's impossible to "project into your retina" from an angle and make the image appear to cover other parts of your vision that do not intersect with the projection system, because your eye's lens (like any other lens) is designed to not allow this to happen.
It's cool that we have different approaches to VR competing with each other, but let's not let the marketing folks get away with hand-wavey BS claims.
Re:What could possibly go wrong? (Score:4, Insightful)
It sounds to me like you're worried that the developers understand the technology as little as you do.
No, images arrive at our retina through means the human body has been using for thousands of years.
Having a piece of technology draw it directly onto your retina is different. And anybody who has ever seen screen burn-in on a monitor will know why it's different.
It's no different at all though. In everyday natural means, light passes through the eyeball to arrive at the retina. In this display, it also passes through the eyeball to arrive at the retina. Naturally, our pupils adjust to allow a comfortable amount of light through. That doesn't change here, either - the pupil can still adjust to suit the viewer's preference.
If too much natural light gets through the pupil, we instinctively blink or squint to avoid burning. That only fails when the viewer intentionally keeps their eyes open (such as kids staring at the sun), when too much energy gets through in the time it takes to execute the blink (such as powerful lasers), or when the energy being absorbed is outside the range of human perception (IR or UV damage).
Fortunately, we actually have a pretty good idea of how much energy is required to burn the retina, and we can easily make LEDs that stay under that threshold. Since the wavelength of an LED is uniform, there's very little risk of any IR or UV damage, as well.
The biggest hazard to this thing is that some idiot might try to wear it while walking, and be hit by a car. That proves that walking is horribly dangerous compared to safer alternatives like being inside the car, even though feet are the locomotive means the human body has been using for thousands of years.
Yeah, it looks like "Retinal" is misleading... (Score:5, Insightful)
...because this doesn't look at all like the laser retinal scanners from 10-15 years ago. And that's a good thing.
I got to try one of the laser retinal scanners at SIGGRAPH ages ago. I was pretty excited, because they promised to dodge the corrective-lenses issue -- in effect, it's as though you're stopping the eye down to a microscopic aperture, which means focus and aberration issues become arbitrarily small. The problem, though, was diffraction artifacts, and they were overwhelming -- there were big, heavily-fringed blobs at fixed positions in the image, and you couldn't make them go away.
Laser technology has come a long way since then, but it doesn't matter. As far as I know, there's nothing that technology can do to overcome this fundamental flaw.