6 ms·

3D LED printer makes a contact lens display possible

60 points by mmastrac 12y ago

sillysaurus3 12y ago
The article talks about power requirements and the manufacturing process, but seems to leave out that any image projected into your eye from 0cm away will be blurry beyond recognition. The eye won't be able to focus on it. Has research overcome this limitation? It's very interesting to think that it's possible to project a sensible image into an eye from point blank.
- SapphireSun 12y ago
  That's only the case if the LEDs transmit light in a broad cone or hemisphere. If the cones are very tight (like at laser in the most extreme incarnation), you can point the light sources at different angles and force it to map onto the retina properly. The important point is to reduce the circles of confusion acceptably. You don't necessarily need them to be zero radius.
  - akinity 12y ago
    Microlenses! The article Geek.com links to located: http://spectrum.ieee.org/biomedical/bionics/augmented-reality-in-a-contact-lens/0 http://spectrum.ieee.org/biomedical/bionics/augmented-realit... is probably a better read.
    - jotm 12y ago
      Or wait until contact lens displays with Retina resolution (the Apple iEye, perhaps)? :-)
      - sp332 12y ago
        The Retina(tm) retina!
- deleted 12y ago
  [deleted]
rexignis 12y ago
Unless I missed something when we were covering eye physiology at uni, contact lens screens are useless. The area we can actually attend to and process data is tiny, which means the screen has to be directly in the center of the contact. For example: A physically separate screen means you can swivel your eyeball and look at a different bit of text on a book page, or a different character on a movie screen. With a contact lens display the content you are attending to is always on the center and swiveling your eyeball to change targets will do nothing.
- whtrbt 12y ago
  Is it feasible to move the content instead?
- sillysaurus3 12y ago
  If the lens knows its own orientation, then its display can change with the orientation. The lenses themselves don't need to embed gyros. I can imagine wearing an upside-down U over the bridge of your nose which has embedded sensors that measure where you're looking.
- wyager 12y ago
  >swiveling your eyeball to change targets will do nothing. Unless you put a MEMS accelerometer/gyro on the contact lens and change content as the user moves their eye. These are engineering problems, not insurmountable physics problems. Saying stuff like "contact lens screens are useless." is unrealistically pessimistic :)
- cma 12y ago
  Pair it with eye tracking. Main problem I see with it is LEDs on a contact lens wouldn't be in focus, at least without some other optics to make them more directional.
  - mistercow 12y ago
    That problem seems reasonably solvable. The main problem I see is that saccades are ridiculously fast, so not only does the eye tracking have to be extremely precise, but the latency for the track-update-display pipeline has to be tiny. This problem is already difficult for head motion. Doing it at the eyeball level is way more ambitious.
veb 12y ago
Wouldn't something like this cause extreme eye-strain and/or headaches? Even if you could make sense of the display...
- sp332 12y ago
  You don't have to focus on a screen that's that close to your eye. The pixels are so small and so close to your eye that the light doesn't disperse much before it hits your retina. That means the dots of light will seem to be in focus no matter how you focus your eyes.
  - jonmrodriguez 12y ago
    That is not true; please be careful to do research before posting so you don't spread misinformation. If a light source is diffuse/omnidirectional, then it will be blurrier the farther it is from the distance your eye is focusing on. Only if the light is a ray (a collimated beam with very little spread and very small diameter), such as the ray produced by a laser, then it will be in focus regardless of the distance at which it is produced.
wyager 12y ago
Jesus, these comments are so pessimistic. As of now, the three top-level comments are "Wouldn't this cause headaches?", "Wouldn't these have a uselessly small viewing area?", and "Wouldn't these be too blurry?". Come on, people; have some imagination. These aren't even show-stopping physical limitations (which humanity has sidestepped thousands of times before); these are relatively minor engineering problems. Even as someone with essentially no experience in this area, I can think of a few potential solutions to the complaints thus far. The eye strain and focus issues are solved by using pre-collimated laser light instead of LEDs. Our fabrication isn't quite there, but again, it's an engineering challenge. The viewing area size is expanded by eye tracking (possibly via sensors in the contact lens). It's good to question these sorts of things, but at least start with interesting questions!
- throwaway3453 12y ago
  Pedantry is a Hacker News tradition. Negative comments are much more plentiful because they're easy. Better not discuss this for too long. The moderation team is extremely averse to meta discussion and introspection.
- gus_massa 12y ago
  There is a lot of hype out there so many stories are welcome with skepticism. The advantage is that you can post here more technical details. I still don't understand how you are going to focus an image that is jut on the top of the cornea. The lens of the eye can't adjust to this distance. For example, Google glass has some external lens so the virtual monitor image is far enough. (I n't find good digrm now, but this is an interesting discussion http://www.reddit.com/r/askscience/comments/19plgu/how_can_google_glass_produce_a_sharp_visible/ http://www.reddit.com/r/askscience/comments/19plgu/how_can_g... ) Do you have a diagram that shows how the image will be formed in the retina? (I also think that the saccades are a problem, but I don't know enough about that subject to weight the technical information.)
vertis 12y ago
'This rabbit got to wear an “active contact lens,” and showed no observable ill effects.' sounds so much better than 'animal testing has so far suggested no observable ill effects'
spurgu 12y ago
I'm imagining the Blue Screen of Death filling your area of vision.
pluma 12y ago
Somehow the first thing that came to my mind is "contact lens low-light amplifiers" (e.g. for military use or driving vehicles at night). I'm not really sure this would be at all possible, but I find the idea much more intriguing than contact lens HUDs.

60 points by mmastrac 12y ago

The article talks about power requirements and the manufacturing process, but seems to leave out that any image projected into your eye from 0cm away will be blurry beyond recognition. The eye won't be able to focus on it. Has research overcome this limitation? It's very interesting to think that it's possible to project a sensible image into an eye from point blank.

SapphireSun 12y ago
That's only the case if the LEDs transmit light in a broad cone or hemisphere. If the cones are very tight (like at laser in the most extreme incarnation), you can point the light sources at different angles and force it to map onto the retina properly. The important point is to reduce the circles of confusion acceptably. You don't necessarily need them to be zero radius.
- akinity 12y ago
  Microlenses! The article Geek.com links to located: http://spectrum.ieee.org/biomedical/bionics/augmented-reality-in-a-contact-lens/0 http://spectrum.ieee.org/biomedical/bionics/augmented-realit... is probably a better read.
  - jotm 12y ago
    Or wait until contact lens displays with Retina resolution (the Apple iEye, perhaps)? :-)
    - sp332 12y ago
      The Retina(tm) retina!
deleted 12y ago
[deleted]

rexignis 12y ago

Unless I missed something when we were covering eye physiology at uni, contact lens screens are useless. The area we can actually attend to and process data is tiny, which means the screen has to be directly in the center of the contact. For example: A physically separate screen means you can swivel your eyeball and look at a different bit of text on a book page, or a different character on a movie screen. With a contact lens display the content you are attending to is always on the center and swiveling your eyeball to change targets will do nothing.

whtrbt 12y ago
Is it feasible to move the content instead?
sillysaurus3 12y ago
If the lens knows its own orientation, then its display can change with the orientation. The lenses themselves don't need to embed gyros. I can imagine wearing an upside-down U over the bridge of your nose which has embedded sensors that measure where you're looking.
wyager 12y ago
>swiveling your eyeball to change targets will do nothing. Unless you put a MEMS accelerometer/gyro on the contact lens and change content as the user moves their eye. These are engineering problems, not insurmountable physics problems. Saying stuff like "contact lens screens are useless." is unrealistically pessimistic :)
cma 12y ago
Pair it with eye tracking. Main problem I see with it is LEDs on a contact lens wouldn't be in focus, at least without some other optics to make them more directional.
- mistercow 12y ago
  That problem seems reasonably solvable. The main problem I see is that saccades are ridiculously fast, so not only does the eye tracking have to be extremely precise, but the latency for the track-update-display pipeline has to be tiny. This problem is already difficult for head motion. Doing it at the eyeball level is way more ambitious.

veb 12y ago

Wouldn't something like this cause extreme eye-strain and/or headaches? Even if you could make sense of the display...

sp332 12y ago
You don't have to focus on a screen that's that close to your eye. The pixels are so small and so close to your eye that the light doesn't disperse much before it hits your retina. That means the dots of light will seem to be in focus no matter how you focus your eyes.
- jonmrodriguez 12y ago
  That is not true; please be careful to do research before posting so you don't spread misinformation. If a light source is diffuse/omnidirectional, then it will be blurrier the farther it is from the distance your eye is focusing on. Only if the light is a ray (a collimated beam with very little spread and very small diameter), such as the ray produced by a laser, then it will be in focus regardless of the distance at which it is produced.

wyager 12y ago

Jesus, these comments are so pessimistic. As of now, the three top-level comments are "Wouldn't this cause headaches?", "Wouldn't these have a uselessly small viewing area?", and "Wouldn't these be too blurry?". Come on, people; have some imagination. These aren't even show-stopping physical limitations (which humanity has sidestepped thousands of times before); these are relatively minor engineering problems. Even as someone with essentially no experience in this area, I can think of a few potential solutions to the complaints thus far. The eye strain and focus issues are solved by using pre-collimated laser light instead of LEDs. Our fabrication isn't quite there, but again, it's an engineering challenge. The viewing area size is expanded by eye tracking (possibly via sensors in the contact lens). It's good to question these sorts of things, but at least start with interesting questions!

throwaway3453 12y ago
Pedantry is a Hacker News tradition. Negative comments are much more plentiful because they're easy. Better not discuss this for too long. The moderation team is extremely averse to meta discussion and introspection.
gus_massa 12y ago
There is a lot of hype out there so many stories are welcome with skepticism. The advantage is that you can post here more technical details. I still don't understand how you are going to focus an image that is jut on the top of the cornea. The lens of the eye can't adjust to this distance. For example, Google glass has some external lens so the virtual monitor image is far enough. (I n't find good digrm now, but this is an interesting discussion http://www.reddit.com/r/askscience/comments/19plgu/how_can_google_glass_produce_a_sharp_visible/ http://www.reddit.com/r/askscience/comments/19plgu/how_can_g... ) Do you have a diagram that shows how the image will be formed in the retina? (I also think that the saccades are a problem, but I don't know enough about that subject to weight the technical information.)

vertis 12y ago

'This rabbit got to wear an “active contact lens,” and showed no observable ill effects.' sounds so much better than 'animal testing has so far suggested no observable ill effects'

spurgu 12y ago

I'm imagining the Blue Screen of Death filling your area of vision.

pluma 12y ago

Somehow the first thing that came to my mind is "contact lens low-light amplifiers" (e.g. for military use or driving vehicles at night). I'm not really sure this would be at all possible, but I find the idea much more intriguing than contact lens HUDs.