Small problem.. your eye isnt as easy top deal with as a silicon device. if the laser is powerful enough it will boil the liquid in the eye and make your eyeball explode, if it traumatizes a small spot that spot can bleed causing swelling in the eye, make the retina fall off the back of the eye, blood to contaminate the optical fluid, etc... unfortunately organics are not as predictable as logic would denote.. a friend of mine only caught .1ms of eye exposure to a uv cutting laser (tracking across a table and a reflection hit him).. he is now basically blind in that eye due to the lens changing it's chemical composition. this is extreme power compared to the eye display, but it's really a crap shoot wither subject A can have no damage while subject B will run around screaming "my eye my eye!" as for a laser scanning system into the eye, the intensity wouldnt have to be any greater than a night light. although I see problems with data being lost as the eye contracts due to high amounts of ambient light. that is alot of movement from total darkness to a sunny snow covered slope. > On the topic of #2, I have a question. All right, so if your scanner > fails, whatever the laser's pointing at will fry. *But*, how extensive > will the damage be? The whole idea is to have the laser be focused enough > to illuminate only one pixel's-worth of the subject's retina. So if the > heat of the laser doesn't start damaging adjacent tissue, you'll only burn > out one "pixel" of the subject's eye, before whatever safety features of > the system turn the laser off. Given how human vision works, my bet is > that the subject would either not notice *anything*, or the subject would > be able to rapidly compensate for the loss of vision. And this is all > assuming that the hypothetical safety features are too slow to prevent the > damage (which they might or might not be). Still, I doubt that people > would be all that happy about dead pixels cropping up on their retinae. > Look how much of a big deal they make of dead pixels on laptops! > > Another way of reducing the probabilities of damage would be to have the > "home point" of the laser (where it would point if no deflection were > performed) point to the retina's natural blind spot. That wouldn't help if > the laser got stuck at some set divergence, of course. > > Does anyone have any hard data on how much light is necessary to cause > permanent damage? If it's say, 50x what the maximum brightness of a normal > pixel is, then you've got 50x the scan time of one pixel to detect the > system failure and shut off or emergency-divert the laser. For a > 1000x1000x60Hz system, that would be about 0.83 microseconds before damage. > > John Flanagan > > -- > Subcription/unsubscription/info requests: send e-mail with subject of > "subscribe", "unsubscribe", or "info" to> Wear-Hard Mailing List Archive (searchable): http://wearables.ml.org -- Subcription/unsubscription/info requests: send e-mail with subject of "subscribe", "unsubscribe", or "info" to
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