
The smallest large display would be projected straight onto your retina - rolph
https://hackaday.com/2020/04/15/the-smallest-large-display-is-projected-straight-onto-your-retina/
======
AndrewKemendo
I'm not sure if there is a good short primer on Retinal Displays or not, but I
don't think this is it.

As the article itself outlines, it's been decades of research and we haven't
really been able to make any practical progress yet. There are a lot of
reasons for this that are as much social as they are technical.

At my previous company a few years ago we took a crack at a concept [1], but
never got it off the ground because prototype costs were in the millions and
there are only a few places that we could source the kind of hardware you need
to build these things.

Last I checked in 2017, Oculus/Facebook was making the most progress on this
but even then were having trouble miniaturizing things. I'm really curious
where they are with it.

[1]
[https://pdfaiw.uspto.gov/.aiw?docid=20180131926&SectionNum=1...](https://pdfaiw.uspto.gov/.aiw?docid=20180131926&SectionNum=1&IDKey=363814FA3947&HomeUrl=http://appft.uspto.gov/netacgi/nph-
Parser?Sect1=PTO1%2526Sect2=HITOFF%2526d=PG01%2526p=1%2526u=%25252Fnetahtml%25252FPTO%25252Fsrchnum.html%2526r=1%2526f=G%2526l=50%2526s1=%25252220180131926%252522.PGNR.%2526OS=DN/20180131926%2526RS=DN/20180131926)

~~~
krenzo
What exactly cost so much? You can build a retinal display using a $200 off-
the-shelf laser projector if you turn down the power and add less than $100 in
lenses. I've done it, and I've even managed to get it up to 8K resolution with
some more time and money thrown at it. I've since formed a company to try to
commercialize it: [http://www.alphalux.io](http://www.alphalux.io)

~~~
kempbellt
Not sure what you are attempting to commercialize, but your website doesn't
explain at all what you have made. Unless I'm supposed to guess it from your
background picture of 3d rendered glasses with some sensors in them...

From most studies I've read on the subject, there are a couple big issues.
Firstly, physics is hard. It's very difficult to get a useful amount of
digital information presented that closely to your eye, where it is in focus,
and comfortable to look at. Scaling up resolution beyond a low-res screen is
even more difficult. Secondly, tech just isn't there yet. The closest thing
I've seen in the market is Google Glass, and that was a huge flop. It also
looked dorky as hell, while providing very little _real_ value. Sure, you
could read a text, if you squinted and focused your attention up and to the
right, but at that point, pulling out your phone is just as easy. It it also
makes you look like a strange android while taking your attention away from
the real world.

For a product like this to work in the market it has to meet a lot of
requirements. Resolution, invisibility (as in, it doesn't feel like you're
wearing a clunky awkward device on your face), battery life, safety (you're
shining light into your eyes), and provide real, _useful_ , functionality.

Useful functionality, to make it worth caring about a device like this, is
_good_ augmented reality integration. And I mean _very good_. If you put the
device on your face and the mapping of the real world stutters for a second,
you're going to hate it and never use it - and no one will buy it.

Also, no, being able to project a little cartoon monster on the surface of a
table is not "useful" AR functionality...

~~~
kbenson
> Also, no, being able to project a little cartoon monster on the surface of a
> table is not "useful" AR functionality...

I would think being able to do that means you've solved most the hard problems
you mentioned, so if it can be done well it means we've achieved a certain
level of usefulness.

Sort of like how bouncing a white square between two movable white rectangles
was a "useful" bit of functionality for consumer AV electronics. Pong isn't
exactly blowing anyone's mind now, but it did mean they had to solve a lot of
problems to make a machine that could interface with current televisions, deal
with user input, do it and update the display within an acceptable time period
so it was responsive, and hit a cost and form factor so the general public
could make use of it.

~~~
kempbellt
> I would think being able to do that means you've solved most the hard
> problems

I guess the other hard problem, besides just creating the tech, is real-world
application,

Reminds me of the Leap Motion device. The creators made some really cool tech,
and it works pretty well for what it is, but most people struggle to find a
really useful application for it.

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Mizza
Saying this, I feel a bit like somebody in the 1800s saying they don't want to
board a train because they don't want to suffocate, but here it is:

I don't want any lasers shone directly into my eyeballs because I don't want
to go blind.

~~~
pasabagi
Well, it is definitely one of those technologies where it doesn't pay to be an
early (first decade) adopter. For all those people who wouldn't board a train,
there were also people who didn't take their cocaine prescriptions, lick their
radium paintbrushes, or take their thalidomide.

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bodhibyte
Virtual Retinal Displays (VRD) have been around for a while (1). More recently
entering the consumer market. I didn't see the article mention the Avegant
Glyph (2)

1\.
[https://en.wikipedia.org/wiki/Virtual_retinal_display](https://en.wikipedia.org/wiki/Virtual_retinal_display)

2\. [https://avegant.com/video-headset](https://avegant.com/video-headset)

Edit: formatting

~~~
entropicdrifter
A DLP projector for your retinas. Cool concept. I bet the parts are cheaper
than the equivalent laser setup.

~~~
errantspark
Looks like they're dead, I wonder if the MEMS latency issues killed it.

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newsbinator
I guess the ultimate version of this is figuring out how to get your brain to
generate the right image via direct simulation of the visual cortex, without
painting anything on your retina at all.

~~~
lucb1e
Is that just a "that would be cool" or do you know of research into this (even
so much as a feasibility study)?

~~~
mhh__
I would keep an eye on Valve.

I don't think they're anywhere near doing it yet but Gabe Newell heavily
implied that he wants to steer Valve in this direction in his recent interview
about Half Life: Alyx on IGN.

~~~
cjsawyer
I wonder if the logos with the red handle in the eye then on the back of the
neck was foreshadowing

~~~
filoleg
That would be cool, but I doubt that was the original intent, given how old
that logo is and that the "red handle" is just a valve, simply referencing the
company name.

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grawprog
What kind of health issues would this type of technology cause? I can't see it
being very good for your eyes to have them focused on lasers being projected
directly into them into at extremely close range for long periods of time on a
regular basis.

~~~
Wowfunhappy
I'd also be concerned about, what happens if something goes wrong? What
happens if there's some sort of power delivery issue, and the laser burns far
too bright just for an instant before dying?

Is that an unfounded concern?

~~~
rectang
It's analogous to in-ear monitors.

[https://blog.64audio.com/protecting-your-hearing-while-
weari...](https://blog.64audio.com/protecting-your-hearing-while-wearing-in-
ear-monitors/)

> _Most pro-level IEMs are capable of producing SPLs (sound pressure level)
> well above 120db. A phantom power spike or a microphone falling on the floor
> can easily produce a signal loud enough to damage your hearing._

The article above recommends putting a brickwall limiter on the monitor mix.
However, a brickwall will only do so much for a sudden screech centered at
3kHz, right in the zone where human hearing is the most sensitive. And what if
the limiter gets disabled? Murphy's Law guarantees that at some point the
safety system will fail.

The only way to guarantee that devices like these won't emit signals which
damage your sensory organs is to make them _physically incapable_ of producing
such signals.

~~~
benibela
Computer interfaces are dangerous

I have been wearing headphones a lot recently and I think I got an ear
infection from them. I barely slept the last 2 days because my ears are
itching so much. Although only when I lay, not when I sit.

And I purposely have been using over-ear headphones rather than in-ear
devices, so I thought you do not get an infection from over-ear headphones

~~~
grawprog
I can't use in the ear head phones at all. Ever since I was young they've
given me ear infections. They're also terrible for your ear. Your tragus is
there to help protect your eardrum from loud noises, among other things.
Sticking noise emitting things behind it is a bad idea.

I've been alright with over the ear style ones for the most part. Though I can
see why they, noise cancelling ones especially, could cause infections if worn
for long periods.

They create moist anaerobic environments liked by a lot of bacteria and
because headphones tend to be left around or carried outside, they're not the
cleanest things around. So as they sit nice and snug around your ears,
bacteria have a nice happy place to live all cuddled up close like to the
entrances to your ears.

~~~
perl4ever
I mostly don't use ear buds, but when I do/did I'd wipe them with rubbing
alcohol before using. Not, like, constantly, but after putting them down for
more than a moment, every trip to the gym, etc.

~~~
grawprog
I've been prone to ear and sinus infections since I was a kid. Apparently I
have narrow sinuses. I end up with a sinus infection nearly every time I get
sick.

To be fair, I find the sound quality lacking on most ear buds, even expensive
ones.

When it comes to low frequencies, the size of cone makes a difference. You'll
never get the same kind of bass from an earbud as an over the ear headphone or
a speaker.

Music just isn't the same without bass or with lackluster bass. Bassvin most
tracks is the bridge between melody and rythym and in many genres actually
carries the song. If I had a choice between high quality treble and lakcluster
bass, like most ear buds offer, despite, marketing and lousy high end with
full bass, id' take the latter every time.

------
gaze
So the power from the optical system is spread over the retina by the MEMS
mirrors. What happens if the laser stays on and one or both of the scanners
stops?

~~~
willis936
This is the first scary question that everyone asks with these devices,
because the answer is "you burn a hole in your retina".

It is an inherent danger in the system, but I would be interested in reading a
full risk analysis on this type of system. Industrial processes always have
risk analysis and avoidance, with failsafe for all possible failure modes
being desired. I wonder what kind of hardware failsafes you could put into
this. You never, under any circumstances, want to burn someone's eye. But you
also don't want someone's expensive toy to brick itself because they jumped
with it on.

~~~
mcguire
[https://journal.burningman.org/2015/03/black-rock-
city/tales...](https://journal.burningman.org/2015/03/black-rock-city/tales-
from-the-playa/theres-a-black-dot-in-the-middle-of-everything-i-see/)

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russdill
Excellent reality check "Lasers Are Not Magic" [http://doc-
ok.org/?p=1386](http://doc-ok.org/?p=1386)

"Can I make a full-field-of-view AR or VR display by directly shining lasers
into my eyes?" \-- No.

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twodave
Immediately thought of the Bosch Light Drive[0] product when I saw this.
There's been no news since they were unveiled, though, as far as I can tell...

[0] [https://www.bosch-sensortec.com/products/optical-
microsystem...](https://www.bosch-sensortec.com/products/optical-
microsystems/smartglasses-light-drive/)

~~~
andrewla
That is mentioned in the article -- BML500P is the part number for the
unreleased thing.

~~~
twodave
Ah, good catch. I skimmed for the Bosch product but didn't see it the first
time.

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jcims
Seems like this is something that could eventually be placed onto a contact
lens (maybe just the reflective part) to help with alignment.

Also I wonder if a lightfield concept could be used to allow the lens in your
eye to focus the image so you don't get that weird 'permanently in focus'
effect that has to be somewhat jarring.

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josephpmay
VRDs sound great in theory, but the more you learn about them the more you
realize that they aren't the right solution for the problem. Compared to other
AR optics approaches, they're vastly more expensive, more dangerous, and have
more limitations to overcome. For example, a VRD will only display if your
eyes are looking in one direction (see the North glasses), so a VRD-based
headset would need eye tracking (and vastly more complex optics to move the
image around) for basis use.

Diffractive optics can achieve much better effects at a fraction of the cost
and without any risk.

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voltron101
I would be really interested in the visual correction opportunities offered by
this kind of technology. I suffer from a rare cornea disease called Pellucid
Marginal Degeneration that results in a very disfigured cornea. It would be
amazing to have a pair of glasses that scan your cornea for abnormalities, and
then adjust the angles at which photons hit your eye in a way that "cancels
out" the astigmatic abnormalities.

~~~
benibela
That is what I am interested in too.

I have 3 diopters astigmatism. Or more, the optometrists have trouble
measuring it, their measurement fluctuates between 2.5 and 3.5 diopters. If
the glasses just slip a little, I can hardly read anything.

I hope I do not develop anything worse. My father had keratoconus.

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joyj2nd
"The smallest large display would be projected straight onto your retina"

Bosch, yes. I am 100% sure I have read about it before on Ycombinator.

[https://spectrum.ieee.org/tech-talk/consumer-
electronics/gad...](https://spectrum.ieee.org/tech-talk/consumer-
electronics/gadgets/bosch-ar-smartglasses-tiny-eyeball-lasers)

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pensatoio
I won’t be an early adopter, but this technology has been a source of great
fascination and excitement for me, and I look forward to the day it becomes a
mainstream reality.

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User23
The prospect of ciliary muscle atrophy (or exhaustion) from longer term use of
this is pretty scary. I wonder if they're considering how to abate that.

~~~
krenzo
How do you deal with ciliary muscle exhaustion from staring at a computer
screen for extended periods?

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rolph
something interesting for the wearables sector.

I thought this would go along with it for safety sake:

[https://news.ycombinator.com/item?id=22634890](https://news.ycombinator.com/item?id=22634890)

------
29athrowaway
Alternatively, use your optic nerve or visual cortex.

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entropicdrifter
I'm surprised nobody's mentioned Magic Leap:
[https://www.theverge.com/2018/8/8/17662040/magic-leap-one-
cr...](https://www.theverge.com/2018/8/8/17662040/magic-leap-one-creator-
edition-preview-mixed-reality-glasses-launch)

