
3D LED printer makes a contact lens display possible - mmastrac
http://www.geek.com/chips/3d-led-printer-makes-a-contact-lens-display-possible-1610256/
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wyager
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!

~~~
gus_massa
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_g...](http://www.reddit.com/r/askscience/comments/19plgu/how_can_google_glass_produce_a_sharp_visible/)
)

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.)

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sillysaurus3
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.

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SapphireSun
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.

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akinity
Microlenses!

The article Geek.com links to located:
[http://spectrum.ieee.org/biomedical/bionics/augmented-
realit...](http://spectrum.ieee.org/biomedical/bionics/augmented-reality-in-a-
contact-lens/0)

is probably a better read.

~~~
jotm
Or wait until contact lens displays with Retina resolution (the Apple iEye,
perhaps)? :-)

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sp332
The Retina(tm) retina!

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vertis
'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'

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rexignis
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.

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cma
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.

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mistercow
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.

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

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sp332
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.

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jonmrodriguez
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.

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pluma
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.

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

