Cheap technology for making optic lenses that could help 2.5B people and NASA(haaretz.com)
haaretz.com
Cheap technology for making optic lenses that could help 2.5B people and NASA
https://www.haaretz.com/israel-news/MAGAZINE-a-simple-israeli-invention-could-help-2-5-billion-people-and-nasa-1.10452996
64 comments
I got so frustrated with eye glasses that never had the correct prescription that I purchased an optometrist kit off Amazon for $200
I had spent over 10,000 at various eye doctors.
Helped me figure out what was going on. ( unstable prescription)
Helped me figure out what was going on. ( unstable prescription)
Hacking your eyes - only on Hacker News. You're giving me ideas to the same.
I've actually been thinking: Since glasses can theoretically make objects a certain distance away appear arbitrarily far away to your eyes/brain, could a pair that makes your desk/screen appear infinitely* far away prevent any harmful effects of constantly focussing nearby? That is, if there any--AFAIK, there's no conclusive research regarding nearsightedness or 'eye strain' (which I haven't even seen a satisfying definition of). In any case, focusing far seems more natural,* and I also wonder if a computer screen that appears large and faraway would acquire some of the effect of a TV/theatre.
Correct me if I've erred in the theory below; eyeglasses can be had online for so little that I'm considering ordering a pair if only to see what how it feels.
Typical glasses/contacts prescriptions aren't enough: To a single eye, a corrective lens is indistinguishable to moving everything in the world closer or farther away, but our binocular vision isn't fooled.[0] Your brain would still think the screen is nearby, only you'd have a hard time focussing on it because of the unexpected power required.[1]
[0] https://en.wikipedia.org/wiki/Vergence
[1] https://en.wikipedia.org/wiki/Accommodation_reflex
But the required trickery is exactly what's prescribed as prism correction[2]--a displacement of the world as seen by each eye by a specified angle. The unit of measure, prism dioptres, is conveniently defined as 100 times the apparent distance that an object at a certain distance is displaced by. In our case, we want to, for each eye, displace the screen (which is a known distance away) by half the distance between the eyes, so that the eye must look straight ahead to see any point on the screen, as it would if the screen were infinitely far away.
i.e., a prism power of:
Optical power is approximately additive, so including existing correction:
[2] https://en.wikipedia.org/wiki/Prism_correction
[3] https://en.wikipedia.org/wiki/Dioptre
[4] http://www.langleyflyingschool.com/Pages/Human%20Factor--Emp...
Edits: clarity; 100x, not 1/100x
Addendum:
The prisms are horizontal and base-in. To actually make something 500 mm from your eyes appear infinitely far away, given a typical pupillary distance of around 30 mm, would require a very high prism power of 6. The typical max seems around 5, though, which isn't too far off.
Illustration: Rays of light (/\) originating from a point (.) pass through the glasses (=<|==|>=), become parallel as if originating from infinity (|| ||), pass through the cornea/lens of each eye (<=> <=>), travel through the eyes (O O), and converge (\/ \/) on the retinas into images (* *).
Correct me if I've erred in the theory below; eyeglasses can be had online for so little that I'm considering ordering a pair if only to see what how it feels.
Typical glasses/contacts prescriptions aren't enough: To a single eye, a corrective lens is indistinguishable to moving everything in the world closer or farther away, but our binocular vision isn't fooled.[0] Your brain would still think the screen is nearby, only you'd have a hard time focussing on it because of the unexpected power required.[1]
[0] https://en.wikipedia.org/wiki/Vergence
[1] https://en.wikipedia.org/wiki/Accommodation_reflex
But the required trickery is exactly what's prescribed as prism correction[2]--a displacement of the world as seen by each eye by a specified angle. The unit of measure, prism dioptres, is conveniently defined as 100 times the apparent distance that an object at a certain distance is displaced by. In our case, we want to, for each eye, displace the screen (which is a known distance away) by half the distance between the eyes, so that the eye must look straight ahead to see any point on the screen, as it would if the screen were infinitely far away.
i.e., a prism power of:
100 * 0.5 * (pupillary distance) / (distance to screen)
Optical power is approximately additive, so including existing correction:
1 / (distance to screen) + (power of prescription)
[2] https://en.wikipedia.org/wiki/Prism_correction
[3] https://en.wikipedia.org/wiki/Dioptre
[4] http://www.langleyflyingschool.com/Pages/Human%20Factor--Emp...
Edits: clarity; 100x, not 1/100x
Addendum:
The prisms are horizontal and base-in. To actually make something 500 mm from your eyes appear infinitely far away, given a typical pupillary distance of around 30 mm, would require a very high prism power of 6. The typical max seems around 5, though, which isn't too far off.
Illustration: Rays of light (/\) originating from a point (.) pass through the glasses (=<|==|>=), become parallel as if originating from infinity (|| ||), pass through the cornea/lens of each eye (<=> <=>), travel through the eyes (O O), and converge (\/ \/) on the retinas into images (* *).
.
/ \
// \\
// \\
/// \\\
/ / \ \
// / \ \\
/ / \ \
_,,,-^^^| |^^^-,,,_
==<________|=========|________>==
| | | |
|___| |___|
O<_____>O O<_____>O
O \ / O O \ / O
O \ / O O \ / O
O * O O * OI wonder if an easier solution, albeit maybe a bit too cyberpunk dystopian, would be to just work in a pitch black room where you could use a projector shining on the farthest wall.
You'd have to be able to touch type though, otherwise every extra inch of distance between keyboard and monitor is somewhat fatiguing when you are constantly glancing up and down.
You'd have to be able to touch type though, otherwise every extra inch of distance between keyboard and monitor is somewhat fatiguing when you are constantly glancing up and down.
Tried it. Big 4K screen across the room. Spent a year in a pitch black room with one eye covered. Sorta worked, but not well. Diamox fixed vision issue much better.
"a corrective lens is indistinguishable to moving everything in the world closer or farther away"
This is not how it works. You seem to confuse focus and magnification. That said the display in VR goggles is set at a specific focus distance, and there is a fair chance it is set at infinity. When you look in VR goggles you eyes are at rest, focus-wise. Seems to be what you are looking for.
This is not how it works. You seem to confuse focus and magnification. That said the display in VR goggles is set at a specific focus distance, and there is a fair chance it is set at infinity. When you look in VR goggles you eyes are at rest, focus-wise. Seems to be what you are looking for.
Oops, I oversimplified that explanation. Add, "...and scaling it to have the same angular size". The image on each retina is indeed around the same size as before, only the object is now perceived as massive and distant by the brain.
The simple formulae I used only approximate the glasses and eyes as stacked thin lenses, so there'll be a bit of magnification in practice. I think this is the norm in optometry, though--apparently, the brain adapts with no issue to the mismatched peripheral vision when wearing glasses.
Hmm... Actually, I'm not sure whether practical optometry involves any calculation at all: As I understand it, the optometrist has you subjectively compare lenses that are positioned in the phoropter at the same distance to your eyes as those in your spectacles would be. So the required lens power is measured directly, without any maths.
Strangely, info on how a phoropter is used seems to be entirely missing from the web (i.e., search engines). There really isn't any pop-sci interest?
The simple formulae I used only approximate the glasses and eyes as stacked thin lenses, so there'll be a bit of magnification in practice. I think this is the norm in optometry, though--apparently, the brain adapts with no issue to the mismatched peripheral vision when wearing glasses.
Hmm... Actually, I'm not sure whether practical optometry involves any calculation at all: As I understand it, the optometrist has you subjectively compare lenses that are positioned in the phoropter at the same distance to your eyes as those in your spectacles would be. So the required lens power is measured directly, without any maths.
Strangely, info on how a phoropter is used seems to be entirely missing from the web (i.e., search engines). There really isn't any pop-sci interest?
Yes. Huds for example usually are made so that the image seems as if it's floating in the distance.
Ultimately one could have a light field display to achieve all this in a flat package. It would be like a display consisting of small directional mini displays. It would have some resolution and brightness issues and would be expensive.
Ultimately one could have a light field display to achieve all this in a flat package. It would be like a display consisting of small directional mini displays. It would have some resolution and brightness issues and would be expensive.
AFAIK most sight issues with screen are not caused by the usage of it, but the lack of sun light.
[deleted]
Same for me, except my prescription is stable. The first doctor I went to got it wrong, and every doctor since was too hesitant to change it. One even got it right, but said nothing had changed... They missed that the axis was significantly different, and that had been the problem all along.
[deleted]
This is enough for the basics, but modern lenses are more complex. Eg multifocals for basically anyone over 45, or high end custom lenses that can correct higher order aberrations.
Anyway, the optometrist lenses kits are still there, you can order them from aliexpress.
Anyway, the optometrist lenses kits are still there, you can order them from aliexpress.
Reminds me of this story: https://www.latimes.com/business/lazarus/la-fi-lazarus-why-a...
Basically it is possible to make much more affordable glasses but people like Luxxotica keep it from happening because it cuts into their margins.
That said, making complex lenses this way would make building things like microscope pretty straightforward. There is a lot of optical equipment that needs lenses that this technique could satisfy.
Basically it is possible to make much more affordable glasses but people like Luxxotica keep it from happening because it cuts into their margins.
That said, making complex lenses this way would make building things like microscope pretty straightforward. There is a lot of optical equipment that needs lenses that this technique could satisfy.
The article doesn't explain how they've been able to keep the "affordable glass" competition out of the market though. Natural monopolies are quite rare. My intuition is that this is not a free market and there is some degree of regulatory capture. I'm guessing not just anyone can set up shop and start manufacturing/selling cheap prescription glasses? Can you import them easily?
As far as frames go, Luxxotica exists because of regular old market-consolidation forces (i.e. it owns so many brands that it makes deals with optical stores to be their only supplier of frames.) Same reason you'll see restaurants that only sell soft drinks made by PepsiCo.
But the real interesting puzzle is why there are so few lens manufacturers.
If you Google the names of these (Zeiss, Leica, Olympus, Corning, etc.), you'll likely quickly figure out that 1. there's about one major optical glass producer per country; and 2. all the ones you'll ever hear about in an Western prescription-glass context are headquartered in countries that are key NATO players; and in fact often in the capitols of those countries.
What's up with that?
"Optical glass", besides being in prescription glasses and smartphone cameras, is the key bottleneck in the resolving power of military imaging satellites.
Each one of these companies is an example of the opposite of "regulatory capture" — these companies exist at the behest of the state, as pseudo-nationalized entities. They're essentially defense contractors that happen to make civilian products on the side.
Competitors to these companies aren't allowed to spring up, because any such a competitor would essentially be a mercenary arms-dealer for IMINT materiel assets.
With exactly one high-quality optical-glass company per country, each under said state's thumb, states can easily track where everything (of sufficient resolving power) that that optical-glass company makes, goes.
It's basically the same reason that there's only a few companies in the world making highly-precise gyroscopes (that could be used for missile guidance); or making industrial-grade cycling centrifuges (that could be used for uranium enrichment.) States will not permit these to be manufactured "out of sight."
But the real interesting puzzle is why there are so few lens manufacturers.
If you Google the names of these (Zeiss, Leica, Olympus, Corning, etc.), you'll likely quickly figure out that 1. there's about one major optical glass producer per country; and 2. all the ones you'll ever hear about in an Western prescription-glass context are headquartered in countries that are key NATO players; and in fact often in the capitols of those countries.
What's up with that?
"Optical glass", besides being in prescription glasses and smartphone cameras, is the key bottleneck in the resolving power of military imaging satellites.
Each one of these companies is an example of the opposite of "regulatory capture" — these companies exist at the behest of the state, as pseudo-nationalized entities. They're essentially defense contractors that happen to make civilian products on the side.
Competitors to these companies aren't allowed to spring up, because any such a competitor would essentially be a mercenary arms-dealer for IMINT materiel assets.
With exactly one high-quality optical-glass company per country, each under said state's thumb, states can easily track where everything (of sufficient resolving power) that that optical-glass company makes, goes.
It's basically the same reason that there's only a few companies in the world making highly-precise gyroscopes (that could be used for missile guidance); or making industrial-grade cycling centrifuges (that could be used for uranium enrichment.) States will not permit these to be manufactured "out of sight."
In the US at least, EssilorLuxottica owns a large portion of the eye glass shops (Target Optical, Lenscrafters, etc) and eyeMed insurance. VSP another eye insurance company has a similar set up where they own their own glasses maker.
There's nothing really stopping anyone from buying from discount eye glass companies online, but you have to guess at which frames you'll like based on pictures and reviews instead of instore.
There's nothing really stopping anyone from buying from discount eye glass companies online, but you have to guess at which frames you'll like based on pictures and reviews instead of instore.
In poor countries regulations are often much more lax. Especially when it comes to harmless things like glasses.
Impressive improvements on prior work, https://www.instituteofmaking.org.uk/materials-library/mater...
> These glasses contain lenses which can be self-adjusted by the wearer to their prescription, and were developed as a low-cost and accessible eye care solution for people in developing nations. The lens consists of two membranes, in between which silicon oil can be pumped with the syringes on the side of the frames. As fluid is pumped in or out, the focal length of the lens is changed, meaning the lens can be tuned to the specific requirements of the eye. The syringes can then be removed. The inventor of these glasses was nominated for a 2011 European Invention Award.
Affordable freeform optics is especially exciting:
> These optical components are neither convex nor concave, but instead are shaped as topographic surfaces, with light hitting the surface in different areas to achieve the desired result. Such parts can be found in multi-focal glasses, pilot helmets, advanced projector systems, virtual and augmented reality systems, and elsewhere.
> These glasses contain lenses which can be self-adjusted by the wearer to their prescription, and were developed as a low-cost and accessible eye care solution for people in developing nations. The lens consists of two membranes, in between which silicon oil can be pumped with the syringes on the side of the frames. As fluid is pumped in or out, the focal length of the lens is changed, meaning the lens can be tuned to the specific requirements of the eye. The syringes can then be removed. The inventor of these glasses was nominated for a 2011 European Invention Award.
Affordable freeform optics is especially exciting:
> These optical components are neither convex nor concave, but instead are shaped as topographic surfaces, with light hitting the surface in different areas to achieve the desired result. Such parts can be found in multi-focal glasses, pilot helmets, advanced projector systems, virtual and augmented reality systems, and elsewhere.
> As fluid is pumped in or out, the focal length of the lens is changed, meaning the lens can be tuned to the specific requirements
If that could be fast enough, then combined with eye tracking we could have full-field glasses for presbyopia.
If that could be fast enough, then combined with eye tracking we could have full-field glasses for presbyopia.
These are called accommodating intraocular lenses. This is a fairly active area of research with huge potential but current technology is very limited.
As a side note who needs eye tracking when your own retina does that for you. The goal with these IOLs is for their lens power to shift based on contraction of the ciliary muscle (the same way a healthy youthful lens works).
I am certainly curious about the potential impact of this UV curable lens technology on cataract surgery and possibility of new types of IOLs.
As a side note who needs eye tracking when your own retina does that for you. The goal with these IOLs is for their lens power to shift based on contraction of the ciliary muscle (the same way a healthy youthful lens works).
I am certainly curious about the potential impact of this UV curable lens technology on cataract surgery and possibility of new types of IOLs.
I'd guess pumping is too slow. Maybe the mechanism used for liquid lenses in mobile phones (and other applications) could work in a larger lens.
Eye tracking and range finding would still be tricky to do in a small space. But something similar-ish was prototyped in 2017 [1]. Not the best source there, but maybe you can find something better with "liquid lens eyeglasses" or use that source to help find the original research.
Also, not sure if liquid lenses will work for astygmatism very well.
[1] https://www.smithsonianmag.com/innovation/these-smart-glasse...
Eye tracking and range finding would still be tricky to do in a small space. But something similar-ish was prototyped in 2017 [1]. Not the best source there, but maybe you can find something better with "liquid lens eyeglasses" or use that source to help find the original research.
Also, not sure if liquid lenses will work for astygmatism very well.
[1] https://www.smithsonianmag.com/innovation/these-smart-glasse...
What is the UV-cured polymer? I read a paper [1] by Bercovici, didn't see it identified.
[1]https://www.researchgate.net/publication/354978270_Fabricati...
[1]https://www.researchgate.net/publication/354978270_Fabricati...
https://static.cambridge.org/content/id/urn:cambridge.org:id...
In this work, we demonstrate curing of PDMS (Sylgard 184, Dow, MI), and UV adhesive (NOA61, NOA63, NOA81, Norland, NJ) lenses. The PDMS lenses are cured by incubating them at 80 C for 1.5 hr, at 60 C for 4 hr, or at room temperature for 24 hr. The UV adhesive is cured by exposure to light at 365 nm (a 36 W consumer grade nail lamp) for 2-5 min, depending on the thickness of the lens and the specific adhesive chosen. Since both PDMS and Norland adhesives are immiscible in water and have densities between ~1.03 (PDMS) g/mL and ~1.12 g/mL (Norland), the water\glycerol-based immersion liquid allowed us to precisely control the density difference. Since preparation of PDMS involves intense mixing of the base resin with a cross-linker, we degassed the PDMS mixture for 20 minutes before injecting it into the bounding surface, in order to eliminate any bubbles trapped in the fluid due to the mixing.
In this work, we demonstrate curing of PDMS (Sylgard 184, Dow, MI), and UV adhesive (NOA61, NOA63, NOA81, Norland, NJ) lenses. The PDMS lenses are cured by incubating them at 80 C for 1.5 hr, at 60 C for 4 hr, or at room temperature for 24 hr. The UV adhesive is cured by exposure to light at 365 nm (a 36 W consumer grade nail lamp) for 2-5 min, depending on the thickness of the lens and the specific adhesive chosen. Since both PDMS and Norland adhesives are immiscible in water and have densities between ~1.03 (PDMS) g/mL and ~1.12 g/mL (Norland), the water\glycerol-based immersion liquid allowed us to precisely control the density difference. Since preparation of PDMS involves intense mixing of the base resin with a cross-linker, we degassed the PDMS mixture for 20 minutes before injecting it into the bounding surface, in order to eliminate any bubbles trapped in the fluid due to the mixing.
UV curable liquid optical polymer that you can buy on Amazon ... maybe something like https://www.amazon.com/Upgraded-Ultraviolet-Decoration-Trans...
Wasn't there, like a decade ago, some university researcher (MIT?) who came up with the idea for a portable lens forming machine that could make arbitrary lens shapes on demand in the field? Maybe it involved rapid curing plastic or something, and a mold that could be shaped easily.
I remember it being described as great for rural areas where it was unlikely / difficult to ensure you would be able to make a return visit or get the people needing glasses to come back when the lenses were eventually ready.
I remember it being described as great for rural areas where it was unlikely / difficult to ensure you would be able to make a return visit or get the people needing glasses to come back when the lenses were eventually ready.
2014 adjustable liquid lenses: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3933712/
Describes both a dial-based and a less mature fluid-based technology: https://www.youtube.com/watch?v=D9FpEWQkg-w
Dial-based: https://www.designboom.com/technology/eyejusters-self-adjust...
DialVision review: https://www.youtube.com/watch?v=Ge3H0FtGUw8
Describes both a dial-based and a less mature fluid-based technology: https://www.youtube.com/watch?v=D9FpEWQkg-w
Dial-based: https://www.designboom.com/technology/eyejusters-self-adjust...
DialVision review: https://www.youtube.com/watch?v=Ge3H0FtGUw8
> Although making a simple pair of glasses costs just a few dollars, in large parts of the world, cheap glasses are neither made nor sold.
And yet prescription glasses cost two orders of magnitude more than that.
And yet prescription glasses cost two orders of magnitude more than that.
They don't outside of the US.
A good portion of my eyeglasses (custom prescription, with astigmatism correction) have been <$10 drop shipped to the US from Hong Kong, frames and lenses included. The most expensive variations (Transition sunglasses, complicated plastics to be thinner, memory metal frames) were $70, frames and lenses included. Most pairs end up in the $20-$40 range shipped.
All this $150-$600 nonsense in the US just pays for the retail space, the branding, the insurance bureaucracy, and rent-seeking by the Luxxotica cartel.
The downside is that I don't get to try them on beforehand... but nothing so far has been totally unwearable, and buying six pairs for $200, as I did once, addresses that concern pretty well.
A good portion of my eyeglasses (custom prescription, with astigmatism correction) have been <$10 drop shipped to the US from Hong Kong, frames and lenses included. The most expensive variations (Transition sunglasses, complicated plastics to be thinner, memory metal frames) were $70, frames and lenses included. Most pairs end up in the $20-$40 range shipped.
All this $150-$600 nonsense in the US just pays for the retail space, the branding, the insurance bureaucracy, and rent-seeking by the Luxxotica cartel.
The downside is that I don't get to try them on beforehand... but nothing so far has been totally unwearable, and buying six pairs for $200, as I did once, addresses that concern pretty well.
You can buy glasses from online sites owned by the world's largest lens manufacturer who sells the identical lenses to B&M stores. Requires some work to find the right fit between frame and face, but this can be learned. Online price includes one free lens remake, if adjustments are needed.
> You can buy glasses from online sites owned by the world's largest lens manufacturer who sells the identical lenses to B&M stores
Link please!
Link please!
https://www.essilorluxottica.com/ & https://www.essilor.com/en/the-group/activities-and-distribu...
> The Essilor group has set out to develop this channel with the acquisition of pure-player FramesDirect®, EyeBuyDirect®, Coastal®, Clearly®, VisionDirect, MyOptique, elens, eOtica and Coolwinks.
I've used EyeBuyDirect (US), who recently merged with Coastal (Canada).
> The Essilor group has set out to develop this channel with the acquisition of pure-player FramesDirect®, EyeBuyDirect®, Coastal®, Clearly®, VisionDirect, MyOptique, elens, eOtica and Coolwinks.
I've used EyeBuyDirect (US), who recently merged with Coastal (Canada).
Oh, huh. I w as getting my lenses from Coastal and Clearly.
[deleted]
Got a pair of these from prof Silver himself. https://www.ted.com/talks/joshua_silver_adjustable_liquid_fi...
At first glance it would seem the same concept. How is it different (if) ?
Lenses are already quite cheap to make. You can get prescription glasses fitted to a knockoff designer frame of your choice in half an hour for less than $50 in e.g. Shanghais knock off malls. You don't even have to bring your prescription, they use a laser device to measure the glasses you brought with you.
Even in Finland you can get basic standard prescription glasses for 59€, or even second sunglass pair for same price(not polarizing though). And the measurements are free too...
Though these are standard material lenses and price really goes up when you want thinner and lighter for higher refraction.
Still, just how cheap something standardised can be even in country with high labor cost is amazing.
Though these are standard material lenses and price really goes up when you want thinner and lighter for higher refraction.
Still, just how cheap something standardised can be even in country with high labor cost is amazing.
I’ve done this in Beijing. I asked for sunglasses and they gave me the lenses and the frame separately, then at the back of the building, some person dipped the lenses in a dark liquid and after drying, put them in the frame for me. Amazing.
Can someone explain me how this works? The article mentions a "rigid frame". Does that frame need to have the (inverse) shape of the lense? Is the method thus just a way to copy lenses or can it make a truly new (i.e. more precise than all necessary tools) one?
Polymer forms a bubble in the petri dish. Add more material to make the bubble curvature more pronounced or less to flatten it.
The other side is flat.
The other side is flat.
Now, if only we had a cheap way to make perfect paraboloids for giant cheap Newtonian telescopes!
We sort-of do.
https://en.wikipedia.org/wiki/Liquid-mirror_telescope
https://en.wikipedia.org/wiki/Liquid-mirror_telescope
Extremely cool but apparently less useful than one might hope.
"sweat equity" is as cheap as you are willing to work
... after reading the article, spherical lenses are great in many many applications, there is still a place for aspheric optics one of which is large aperture telescopes you can reach without an orchard ladder or drone.
the sibling comment on spinning fluids does lead the question; can the researchers vary the density of their neutral fluid (or polymer) to gradually vary the "local" forces shaping the lens
... after reading the article, spherical lenses are great in many many applications, there is still a place for aspheric optics one of which is large aperture telescopes you can reach without an orchard ladder or drone.
the sibling comment on spinning fluids does lead the question; can the researchers vary the density of their neutral fluid (or polymer) to gradually vary the "local" forces shaping the lens
Like, say, spinning a dense liquid in a container against gravity?
Sounds like you could cure the polymer while the container is spinning...
The original idea (polymer lenses) is definitely a huge potential for amateur astronomes making large refracting telescopes.
At the end of the article they mention being able to make large mirrors with liquid metal using the same technique as for the lenses. I do not quite understand how this is supposed to work.
The original idea (polymer lenses) is definitely a huge potential for amateur astronomes making large refracting telescopes.
At the end of the article they mention being able to make large mirrors with liquid metal using the same technique as for the lenses. I do not quite understand how this is supposed to work.
Fascinsting.
What kind of material they use for lens? The one which reacts to uv light.
I wonder if this tech could be used to make adjustable VR lenses.
But how is the curve of the lens controlled? Is it some sort of surface tension guided by the edge height of the enclosing ring?
It’s a combination of surface tension and buoyancy; the resulting minimum energy surface can be designed to whatever freeform shape you want by controlling the liquid density and the geometry of the frame.
thickness of the membrane, but this will cause fresnel lenses if annular, and complexity if a continuous curve, and also introduce (spherical?) aberration of its own due to non-linear effects on light through a varying sized medium before hitting the "lens" part inside the membrane
this is me thinking in terms of "what things about an inflatable structure change how spherical it becomes, when inflated" and adding in "what does it do to optics"
not an optician, a physicist or an inflatable toy clown.
this is me thinking in terms of "what things about an inflatable structure change how spherical it becomes, when inflated" and adding in "what does it do to optics"
not an optician, a physicist or an inflatable toy clown.
I'm fairly sure that the medium within the ring-shaped mold is homogenous once cured--I don't think it's a cured surface membrane with a liquid interior?
Presumably that's the purpose of the heat-curing process described in their paper, as UV won't be able to penetrate arbitrarily deep into the polymer.
Presumably that's the purpose of the heat-curing process described in their paper, as UV won't be able to penetrate arbitrarily deep into the polymer.
Its injectable. What are they injecting?
They inject a liquid polymer solution into the water+glycerol solution, in the area they want it to be. 'Immiscible' means they won't mix, it'll just form a homogenous bubble/blob in the water. And they carefully adjust the density of the water+glycerol ahead of time to match the density of the polymer, so the blob of polymer neither floats nor sinks. Surface tension affects the shape of the blob caught in the ring mold, which is created ahead of time to produce the shape they want. Then they cure it, 'freezing' the liquid polymer as it solidifies. There's no liquid inside when it's done.
Wow I'd completely misunderstood what was being initially UV cured, I thought it was a "skin" of material to form the shape much as a balloons final shape is influenced by the thickness of the rubber and was inflated. Talk about the bad effects of skim reading!
This sounds almost too good to be true -- could be a game changer for a lot of people!
holy crap...
maybe it is possible to create microstructures using a phase array ultrasound emitter?
maybe it is possible to create microstructures using a phase array ultrasound emitter?
I'm much more excited for the AR/VR usages for this kind of lens tech.
Interesting, but how in the world is this cheaper than injection molding?
This was developed in India decades ago, but I can't find those kits online. Obsolete?