[HN Gopher] Zoomable lens without any moving parts
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Zoomable lens without any moving parts
Author : simonebrunozzi
Score : 165 points
Date : 2021-04-01 07:48 UTC (2 days ago)
(HTM) web link (medium.com)
(TXT) w3m dump (medium.com)
| ta1234567890 wrote:
| So at what scale do we call movement movement? Because things are
| moving inside this lens, but at a molecular/atomic level.
| superkuh wrote:
| To me this kind of sounds like turning a bug into a feature. And
| that's great. I would not doubt if they were having a problem
| with phase shift with temp and thought, "Hey, what if we did this
| intentionally?"
|
| Usually engineers hate the electromagnetic phase shift that comes
| from temperature change, or worse, temp changed caused physical
| shifts in phase of the material. One notable example of this is
| the PTFE dielectric material for coaxial cables which has become
| notorious for the "teflon knee" in it's temperature vs phase
| plot.
| mrdrrobots wrote:
| We actually engineered the material specifically for its
| optical/IR behavior. See:
| https://www.nature.com/articles/s41467-019-12196-4
| touisteur wrote:
| Hey, phase shift is great for radars and radar-like processing.
| If you can control or calibrate it it somehow, you're gold.
| bradgranath wrote:
| No magic photon teleportation happening here: it moves. Just not
| with gears.
| mrdrrobots wrote:
| Co-author here: link to the journal article:
| https://www.nature.com/articles/s41467-021-21440-9
| kurthr wrote:
| I love the idea of these electro-optic (or in this case electo-
| thermal) configurable lenses. and fourier optics in general.
|
| What range of optical wavelengths did this lens operate well
| over, or could a similarly constructed system operate. My
| experience with electron beam exposed PMMA grating/lenses was
| that they were OK over the optical range, but did show
| noticeable dispersion, while for filtered (or laser) optics
| they worked extremely well to replace much thicker/heavier
| system solutions.
| mrdrrobots wrote:
| This was designed for the mid-IR (5.2um). I don't recall its
| bandwidth but is was small on order of 100nm. The dispersion
| of this material in the mid-IR is relatively flat. There is
| active research on dispersion engineering via more complex
| geometry of the 'meta-atoms' to broaden the bandwidth for
| achromatic metalens optics. Other research is actively
| looking to design materials that could have this phase change
| functionality in the visible wavelength range. All stable
| phase change materials to my knowledge strongly absorb in the
| visible range.
| kurthr wrote:
| Thanks a lot for the quick response! I read enough to see
| it was designed for multi-micron, but was hoping it would
| still work down to near-IR. It will be hard to use this for
| depth imagers or standard CMOS at those longer wavelengths,
| but for true IR cameras it could be amazing.
| notjtrig wrote:
| Interesting, looks like the last big lens tech, liquid lenes are
| finally here.
|
| The First Smartphone to Use a Liquid Lens is the Xiaomi Mi Mix
| Fold
|
| https://petapixel.com/2021/03/30/the-first-smartphone-to-use...
|
| Liquid Lens Features, Applications, and Technology
|
| https://www.edmundoptics.com/knowledge-center/application-no...
| bnegreve wrote:
| _[The] camera uses a liquid lens powered by a motor that uses
| precision manipulation on that packet of fluid to switch
| between a 3x telephoto zoom and a macro mode [..]_
|
| If I understand correctly, the lens in the Xiaomi Mi Mix Fold
| does require a mechanical movement to be adjusted (it's also
| clearly visible in the video), so I'm not sure what is the
| point.
| simcop2387 wrote:
| It's a much more compact mechanical movement than a
| traditional focusing system, allowing them to use the same
| sensors for two different zoom levels on the phone. Right now
| this is otherwise being done by using multiple sensors and
| lenses instead.
| ampdepolymerase wrote:
| I remember prior literature on liquid lenses used electric
| charges. It is possible the ones in the phones use mechanical
| movements to get around patents.
| _Microft wrote:
| I think I also remember something like that. It might have
| been an interface between silicon oil and a saline solution
| that was deformed by applying an electric field.
| perryizgr8 wrote:
| You can change the zoom/focus by a lot more if the lens can
| be made to change shape, kind of like the eye. You would need
| to have a much greater degree of movement to replicate it
| with hard lenses.
| seg_lol wrote:
| You could also do things like use different patches of the
| sensor to focus different parts of the scene. Depending on
| how much the lens can morph, it could provide for bifocal
| functionality or limited fly eye.
| KMag wrote:
| What happens to a liquid lens at -60 F / -51 C?
| olejorgenb wrote:
| Another new(?) type of lens:
| https://www.polight.com/technology-and-products/how-does-it-...
|
| The glass is deformed rather than moved. The main selling
| points compactness and very fast change of focus.
| taneq wrote:
| It's impossible to deform something without moving parts of
| it. Still, fast focus is good.
| intricatedetail wrote:
| Always thought that camera lenses the way they are, are the
| already obsolete technology. I mean we can fit billions of
| transistors on a fingernail, but we need this mechanical
| contraption to zoom things? I think this invention is still not
| it, but I am glad the tech in that space is finally going
| somewhere. Don't get me wrong, I love lenses but it feels like
| using something from a last century, even though it was just
| made.
| mkr-hn wrote:
| Lenses are like rockets in that way. The physics of light and
| space are unforgiving and hard to solve.
| tomkat0789 wrote:
| Bah, Caltech can top that. Why bother with a lens? How about an
| optical phased array? :)
|
| https://www.caltech.edu/about/news/ultra-thin-camera-creates...
| tambourine_man wrote:
| I'd also wager on computation vs moving parts, even if those
| moving parts are microscopic.
|
| Possibly faster, more reliable.
| YY-EN40P wrote:
| > It's just a proof of concept right now, but it's a very cool
| concept.
|
| Though metalens need to be heated, it's a very cool concept!
| mikewarot wrote:
| This is essentially a zone plate reflector which has two states,
| and thus switchable focal points.
|
| The images shown lead me to suspect this is a binary zone plate,
| which has a much narrower bandwidth over which it would be
| effective.
|
| However, this is all prototypes, if they can indeed make a zone
| plate that can be addressed as pixels, with finer control over
| phase shift at each pixel, there are quite a few places where it
| would be quite useful, in spite of the narrower bandwidth.
|
| https://en.wikipedia.org/wiki/Zone_plate
| mrdrrobots wrote:
| Co-author here, Not a binary zone plate.
| mikewarot wrote:
| How wide of a bandwidth could this handle? Do you think it
| will be possible to cover the entire visible light spectrum
| some day?
| mrdrrobots wrote:
| It's theoretically possible; this is a very active field of
| research.
| cycomanic wrote:
| That's incorrect, metalenses are not diffractive lenses. They
| continuisly change the local refractive index through
| subwavelength structures. There's a brief introduction and
| discussion about differences with diffractive lenses here:
| https://www.nature.com/articles/s41467-020-15972-9
| amelius wrote:
| Why is "meta" in the name?
| jasonwatkinspdx wrote:
| It's a general category of assemblies / structures that
| mimic a material with unusual or even impossible
| properties: https://en.wikipedia.org/wiki/Metamaterial
| smcleod wrote:
| https://web.archive.org/web/20210403031009/https://www.extre...
| tryonenow wrote:
| It looks like the material is organized on a grid. Imagine a
| lense + algorithm that conforms to the depth map of the FOV. You
| could get super focus (there's probably more appropriate term) in
| a single shot.
| tfolbrecht wrote:
| What you're describing is a light field camera.
|
| It's cool tech, there was a company called Lytro that tried to
| commercialize them a while back.
| namibj wrote:
| No, they are describing a lens that can change the effective
| focus for different regions of the image, so that you can get
| multiple parts in focus at the same time. There are no light
| field tricks here.
| fortran77 wrote:
| > When heated, the atomic structure of the material rearranges
|
| So it does move, just on a smaller scale.
| zackbloom wrote:
| Atomic structure shifts are not conventionally considered
| 'moving'. Most people wouldn't call water turning to ice a
| 'movement'.
| scollet wrote:
| Not until the glaciers show up.
| gpuhacker wrote:
| A glacier is compacted snow, not ice
| bumbada wrote:
| I can warrantee you compacted snow is ice. Just go to
| Greenland, Argentina or Switzerland and see a glacier by
| yourself. You see ice and bubbles(bubbles could grow and
| become caves and over time they go up).
|
| Icebergs are called ICE- berg for a reason, not snow-
| bergs.
|
| If you had a snow that is 1/10 the density of water, just
| 10 meters of snow means 1 atmosphere of pressure. That
| pressure compresses the snow, making 10 meters hold more
| water and more pressure.
|
| There are places in the world with glaciers higher than
| three kilometers(1.8 miles).
| kortilla wrote:
| > Snow comprises individual ice crystals
|
| https://en.wikipedia.org/wiki/Snow
| hn8788 wrote:
| Snow is ice.
| klyrs wrote:
| Just wait til you hear about supersolids
| m463 wrote:
| I was thinking of when water gets over boiling point and
| then is disturbed:
|
| https://en.wikipedia.org/wiki/Superheating#Occurrence_via_m
| i...
| kelsolaar wrote:
| I think that the point is that there is nothing that you could
| really "separate as a part", everything being fused into a
| single piece impossible to disassemble without destroying it.
|
| This is to put in perspective with a Zoom Lens where moving
| parts are designed to be assembled and disassembled:
| https://www.lensrentals.com/blog/2021/01/the-secret-of-the-b...
|
| Also, a heated metal bar dilates and thus moves, not sure it is
| considered having "parts".
| mrdrrobots wrote:
| Define 'move'. All matter 'moves' on some scale even at
| absolute zero temperature.
| intrasight wrote:
| If the phase change causes the whole lens to stretch or shrink,
| then it would fit my definition of "move"
| whymauri wrote:
| before even opening the thread, i knew someone would make this
| comment.
|
| come on guys, we all know what the title means
| jamesgreenleaf wrote:
| It's a valid observation. A lens that could somehow do that
| without moving at all would be pretty magical, and the
| headline plays on this to get your attention. The headline
| could have been "MIT Creates Zoomable Lens That Works Using
| Heat" which is still cool, but not as sensational.
| craftinator wrote:
| Or better yet, "MIT Creates Zoomable Lens That Works by
| Moving More or Less".
| cycomanic wrote:
| By this definition of movement absolutely nothing would do
| anything. If there was electric current you could say, "but
| the electrons are moving in the material". It's like saying
| your stove moves when you cook.
|
| By any reasonable definition without moving parts means
| without any macroscopic (mechanical) parts that move.
| foota wrote:
| Well, I actually thought this was going to be about phased
| array optics, so I guess there is some distinction here.
| cycomanic wrote:
| This is quite close to phased array optics actually.
| m463 wrote:
| I think on sites like HN - even with non-controversial
| subjects - you have to say "improbable" instead of
| "impossible" and stay away from absolutes.
|
| Maybe "zoomable lens with no conventional moving parts", or
| "non-mechanical zooming" or solid-state zoom lens or...
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(page generated 2021-04-03 23:03 UTC)