Hacker News new | past | comments | ask | show | jobs | submit login

But don't lasers need to scan in order to draw a full image (vs just a dot)? Doesn't that necessitate making the actual laser beam brighter than other light entering your eye? Are there any negative consequences to having a bright light scan over your retina quickly vs a dimmer light shining on your entire retina at once? What happens if the scanning mechanism fails and the laser ends up shining on one tiny point in the center of your eye for an extended period of time?

Lots of interesting safety questions unique to this particular display technology.




Remember that A) The laser is close to your eye and shining directly in and B) It's coherent, so it's focused on a single small spot. It doesn't have to be so much brighter than all the light around you given those things.


But it isn't focused on a single small spot; it has to scan across multiple small spots in order to form a recognisable 2d image. If it were just focused on a single small spot the entire time, all you'd see is a dot.

That means one of two things must be true. Either a) the beam is way brighter than other light entering your eye, such that it delivers in a single focused beam the same amount of energy that would otherwise be distributed evenly across the surface of your retina if you were viewing natural light. (Thus the questions I posed in my previous comment.) Or b) the beam is the same brightness as other light entering your eye, meaning the amount of energy in any individual pixel is far _less_ than what your eye receives from natural light. (I imagine this would make the image appear very dim.)




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: