| Author | Message | ||
     Anonymous Rating: N/A |
I have read that such things are being worked on, but do any actually exist yet? If so how much do they cost and what is the resolution? Thanks.  | ||
| Garrett Rating: N/A |
Isn't it dangerous to shine lasers in your eye? This sounds fake | ||
| Anonymous Rating: N/A |
Its been done and its not fake. Depending on wavelength and power it can be quite safe. | ||
| Bricklayer Rating: N/A |
It's the only technology, I'm aware of, that can create a true stereoscopic optical image on the retina. Lenses, by the laws of physics, cannot 100% simulate reality. "Painting" a laser image on the each retina can overcome the limitations of lens systems. | ||
| tj Rating: N/A |
Microvision (www.microvision.com, corporate outgrowth of U of W's HIT Lab) has been attempting retinal scanning for over a decade now; they own most of the patents. They started out using spinning mirrors and their prototypes were huge (not to mention monochromatic), but they've been saved by the advent of MEMS - the deformable micro-mirror. Bricklayer, what do you mean when you say that it's the only way to create a "true stereoscopic optical image on the retina"? Are you referring to focus? Focal distance is one of the many aspects of depth perception that can't be mimicked very well by "image disparity" alone (if anyone doesn't know: image disparity being the angular difference between what each eye sees - the depth effect that shutter glasses use - but there are several depth cues too, although more subtle). As far as lenses not simulating reality... remember that your eyeballs have lenses in them! Retinal scanning *sounds* real cool. It always sounded so much more "high tech" than using microdisplays. But I'm still wondering if it's the ultimate answer. It's definitely good when brightness is an issue, like for "augmented reality" applications where the image displayed must compete with and not be washed out by environmental light. One big problem though is with field-of-view, because the laser scanning has what is called an "exit pupil." That is, you must keep your eye within a distance and orientation where the laser beam can enter through the pupil. I imagine that if you turn your eyeball much to look to the side, it might go outside that exit pupil. I've never tried a Microvision display, so maybe I don't know what I'm talking about. However, if the idea is simply to project an image onto the retina, that doesn't require a lot of additional rocket science. For one, it already happens naturally, as everything we see in reality is as a result of a tiny image of it being projected (upside down) on the back of our eyes already. By the same token, in a HMD, for each pixel of its microdisplay that lights up, you can cast a ray of photons through the optics, then through the eye lens and onto the retina. Because you have so many pixels, you have lots of these rays at lots of angles, so you don't have to do any scanning. In theory, the retinal scanner only has "one pixel" - the laser - which has to be physically directed to fill the area of an entire image. I always thought that when you really think about it, it's all doing the same thing essentially. ...or is it? | ||
| syb Rating: N/A |
RSD = Retinal Scanning Display ============================== I have spoken to a PhD guy who has used a Nomad display - or at least he had some kind of demo of the technology from Microvision. I've been following thier progress on-and-off for about the last 5 years. I'm quite conviced that thier tek is the only thing going that has the *potential* to deliver daylight viewable, life-like imagery in total FOV (120 Deg Diagonal per eye?).... and all in a package that may - eventually - fit into standard spectical glasses formfactors. RSD = True Augmented Reality?... I believe the potential is there. | ||
| Bricklayer Rating: N/A |
tj, Stereoscopic vision provides cues for depth, size, order(distance from viewer). Using hardware/software analogy, the hardware(dual eyeball system)does two things: 1. Focuses on an point in space(Accommodation) 2. Rotates each eyeball to line the point up with the fovea(Convergence) The two images are transmitted from the retina to the brain for software processing. The "image disparity" is sensed by differences in the IPD. Along with focus information the brain processes this information with many other cues(motion, known objects, continuity of image...)to construct a model of the view. I don't know of any way two flat images presented to the eyes through lenses, mirrors, and/or prisms, can provide a point of regard perceived at varying distances in space. Do you? Without accommodation and convergence cues, the information is at best incomplete and probably contradictory. Regards, Craig | ||
| tj Rating: N/A |
Hey Craig... In answer to your question: Nope! I don't know of any microdisplay-(or CRT-)based HMD technology that can vary the apparent distance between the virtual image and the viewer -- especially since the LCD-to-lens distance and the focal length of the lens system are fixed. That is, for example, the Sony HMD specs say: "Simulates a 30-inch screen 4 feet ahead of the viewer." Thus the viewer's eyes always focus on and converge upon a virtual image point as though it was at an actual distance of 4 feet. This obviously causes a problem for augmented reality applications, since the viewer is seeing through the HMD and seeing real-world objects that may vary greatly from 4 feet away. The big question is this: Is the retinal scanner *really* capable of varying the distance of the virtual image, or potentially, different parts of the image? None of the Microvision information I've seen (including their press kit, which unfortunately, but of course, is light on technical detail!) indicates that the projected image appears any other way than flat. And since the laser beam is scanned from a single point (the deformable mirror), thus diverges from that point, it must be passed through some sort of converging lens or other such optics in order to steer the rays through a point where they may be passed through the pupil. However, I haven't seen the Nomad with my own eyes, so I really don't know what I'm talking about. :-( Now if everyone's eyes were cut in half, and the beam could *really* be scanned directly onto the retina (thus all we'd really care about were which photons were hitting which rods & cones -- which is all we really care about in the end anyway)... then it'd be much easier! ...uh, but then nobody would be able to see anything otherwise. ;-) | ||
| Bricklayer Rating: N/A |
tj, After thinking through you comments, I realized my assumption that a raster image would allow a point beam to produce an equivalent image as that produced by many points in 3D space was...uh...well...presumptuous.  You'd have to track accommodation and convergence, generate the appropriate image and somehow align the laser to where the eye is pointed. I've heard of eye tracking, never heard of focus tracking, and wouldn't have a clue as how to keep a laser oriented toward a moving eye. Thanks for pointing this out. Craig | ||
| tj Rating: N/A |
Hey Craig I think all of us are trying to figure this stuff out. Don't get me wrong, I would LOVE to see Microvision (or whoever else) pull it off. If the retinal scanner would indeed be able to simulate different virtual image depths, that would be awesome - a definite breakthrough. I'd have to "see it with my own eyes" though. If they could simulate rays of light coming into the eye from *different angles*, maybe that would be the answer. I'm wondering how it could be done. Perhaps "deformable" optics like that DigiLens thing? (If they are even still in business?) Of course your eye can deform its lens in order to focus. Basically the only solution to the focusing issue in *man-made* devices is to vary distance between lenses. I wonder if anyone has ever invented a man-made deformable lens, like what the eye has? Anyone know? | ||
| Bricklayer Rating: N/A |
Hi tj, Regarding a deformable lens, yes I saw a patent at the US Patent Office web site for this. A fluid filled lens adjustable by hydraulic pressure. Craig | ||
| tj Rating: N/A |
Thanks, I'll hafta look for it on the USPTO site. Do you have to pay if you want to see the whole patent? (or is that the IBM patent site I'm thinking of?) I wonder how good that lens is, or if it's even available commercially? It's amazing how many patents are registered where the applicants have not even tried to commercialize the technology. I've even worked for some big firms where we were attempted to be sued by these people! They think of a very general idea, one that doesn't even need a lot of forethought if you read science fiction, then they get it patented. The unfair part is that they sit on the idea, not trying to make a product of it. They wait around until someone does, then they sue them to try to get a piece of that company's money (even if its product doesn't sell). If the patent system was "fair," it would require people to have to realize their product. Patents are also too easy to get. All the USPTO has to see is that it's not too similar to previous patents. There could be easily accessible *prior art*, but the USPTO doesn't care about that -- it only comes into play when the Patent needs to be shown as invalid in court, and then the onus is upon the defendant getting sued, who has to expend a ton of money just to prove the USPTO had their heads up their asses when granting the patent. That's my opinion. Your mileage may vary. Off the soapbox! Sorry, I didn't mean to take this thread off-topic! :-( | ||
| Bricklayer Rating: N/A |
Hi tj, Sorry about the delayed post, I didn't see your response. Here's the link to the USPTO:http://www.uspto.gov/patft/index.html You can browse all the patents and drawings. You only have to pay to get a hardcopy. This is a fantastic use of the internet by the Feds, they got it right in this area. You might have to download a plug-in to view the images. Go to the help pages for setting up image viewing...it's worth the effort! Craig | ||
| Anonymous Rating: N/A |
Re: Varying the focus for retina scanning displays. A group at the HIT lab presented a paper at this year's SID conference that described tests of a deformable mirror used in combination with a VRD to achieve this effect. As of that time, they had only done static tests with the mirror. The paper is on pages 1324 - 1327 of this year's conference proceedings. It will eventually show up on SID's website, but for now you probably have to find a hardcopy of the proceedings. As for the usefulness of adding the focus feature - the advantages are twofold: 1) Ability to focus on both ral world objects and superimposed virtual information, and 2) Lack of eyestrain etc. due to focus/fixation disparity. As a depth cue, focus is farily useless, since it tends to be overwhelmed by the other cues. Proof of this is available to anyone who wears glasses or contacts. For example, I'm nearsighted, and can't focus on anything farther than about two feet from my eyes. My glasses work by diverging light to create images that are never more than two feet in front of me. In other words, when I look out at the horizon through my glasses, my eyes focus at a plane two feet in front of me. Yet it doesn't look like the horizon is two feet in front of my face. That's becuase all the other cues like disparity, etc. counteract the focus cue and the visual system totally ignores it. Glasses for far sighted people produce the opposite effect. | ||
| Anonymous Rating: N/A |
Re: Varying the focus for retina scanning displays. A group at the HIT lab presented a paper at this year's SID conference that described tests of a deformable mirror used in combination with a VRD to achieve this effect. As of that time, they had only done static tests with the mirror. The paper is on pages 1324 - 1327 of this year's conference proceedings. It will eventually show up on SID's website, but for now you probably have to find a hardcopy of the proceedings. As for the usefulness of adding the focus feature - the advantages are twofold: 1) Ability to focus on both ral world objects and superimposed virtual information, and 2) Lack of eyestrain etc. due to focus/fixation disparity. As a depth cue, focus is farily useless, since it tends to be overwhelmed by the other cues. Proof of this is available to anyone who wears glasses or contacts. For example, I'm nearsighted, and can't focus on anything farther than about two feet from my eyes. My glasses work by diverging light to create images that are never more than two feet in front of me. In other words, when I look out at the horizon through my glasses, my eyes focus at a plane two feet in front of me. Yet it doesn't look like the horizon is two feet in front of my face. That's becuase all the other cues like disparity, etc. counteract the focus cue and the visual system totally ignores it. Glasses for far sighted people produce the opposite effect. | ||
| Anonymous Rating: N/A |
VERY interesting point! | ||
| chetan Rating: N/A |
if somebody wants i-glasses svga 3d hmd please mail me at chetan_s25@yahoo.com it is as good as new.it is just that i cannt keep this luxury with me any more.thanks | ||
| insanerob Rating: N/A |
Varying focal depth. There are materials who's refractive index changes when a voltage is applied. My mate made a crude pair of binoculars using this when he was at University. Im not sure how fast the material reacts to changes in voltage but I wouldn't have thought it would take anywhere near as long as a hydraulic system, that and i'd rather carry a couple of Walkman Batteries round than a compressor :-) You'd have to create a matrix of the stuff, like you would a monochrome LCD screen, just the resolution this would have to be huge to match that of the laser. Check this link if you want to see how one company is using this to make vari-focal glasses to replace bi-focals etc http://www.eggfactory.com/egg_na_062801.html \ | / -RoB- / | \ |
