

Philips Develops Fluid Lenses 165
Lars T. writes "Digital Photography Review has a short report indicating: 'Philips Research at the CeBIT exhibition is demonstrating a unique variable-focus lens system that has no mechanical moving parts. Suited to a wide range of optical imaging applications, including digital cameras.' Here is Philips' press release and the Heise News article (in German) where I first heard about it. The latter also mentions that Philips has recently used the same electrowetting effect in an 'ePaper' display prototype."
I take it as... (Score:5, Insightful)
Suitability for Precision Use (Score:4, Interesting)
Well, duh. Think about the vibration concerns. Any movement not only jiggles the thing but it also takes time for it to settle back down.
Back when I designed a version of this w a a a a y back in the early eighties I was quite paranoid about the issue of how do ya keep the thing from accumulating stuff near the resonant frequencies. I'm not seeing anything in the brief English-language piece about this at all. My puppy allowed for the option of changing focal length by changing ring diameter which, oh btw, made things potentially even worse on that front. On the other hand, IIRC, I made a point of the importance of being willing to switch ring materials to optimize for stuff like ability to dampen vibration.
I wonder if they've figured out yet that when you've got a liquid lens that changes properties by changing electrical charge, you can add impurities to the liquid such that charging the liquid, the liquid will change color. Very precise, very neat, and entirely reversable, at least for as many cycles as they would need for a consumer product.
As I mentioned below, I really *am* gonna have to dig up my old drawings and writeup.
*sigh*
This because I have nothing else to do with my time.
Yeah, right.
Rustin
Re:Suitability for Precision Use (Score:2)
Applications to Eyewear (Score:5, Interesting)
Re:Applications to Eyewear (Score:4, Interesting)
Re:Applications to Eyewear (Score:4, Interesting)
About ten years ago a UK charity demonstrated a pair of spectacles for the developing World that used just this principle. The lens were made of two plastic films separated by a small gap. Syringes filled with water (?) could be attached to the arms of the spectacles. The person needing the glasses would put them on, then the syringes would be depressed and water pushed into the gap between the films. When the wearer saw a sharp image, the syringe could be disconnected.
No need for precision lens grinding technology, no need for a trained optician and most of all cheap to make and replace.
Never saw it again, I guess the curse of 'Tomorrow's World' struck this one down.
Best wishes,
Mike.
Re:Applications to Eyewear (Score:3, Informative)
Re:Applications to Eyewear (Score:2)
Is it better for a person living without access - either physical or financial - to an optician to be able to see something, rather than a blur? It's pretty hard to imagine how the myopic amongst us would manage without access to spectacles, contacts and the like.
Here in the UK
Re:Applications to Eyewear (Score:5, Insightful)
I'd guess that the going much smaller is constrained by capillary action.
Re:Applications to Eyewear (Score:4, Interesting)
In my opinion, the biggest thing preventing this from being used in eyeglasses is the fact that the lens must always be as thick as the greatest magnification 'setting' on the lens. Also, since there is at least 4 different indexes of refraction (air, glass, fluid 1, fluid 2), there is a much greater likelyhood of chromatic abberation and other artifacts. But who knows what another century or so of research would do for this technology.
Re:Applications to Eyewear (Score:3, Insightful)
Re:Applications to Eyewear (Score:2)
Anchoring it would be a heck of a problem. The repeated accelerations whenever you move your eye would put quite a bit of stress on whatever attachment you use to bind this lens to the eye. I'd be concerned about doing damage to the rest of the eye.
Then you get into the question of powering the device. Hiding a battery in your eyeball is just not on--I don't think--and an external power source would
Re:Applications to Eyewear (Score:2)
Vibration Problem for Eyewear (Score:2)
Picture trying to do something as simple as walking quickly with them on.
Boing-boing-boing goes your focal length and center of mass.
Rustin
Re:Applications to Eyewear (Score:3, Interesting)
Fixing Eyes With it (Score:5, Insightful)
I dont know about scaling it up. The article is short on details which relate much to eyewear. Eyeglasses correct a huge range of flaws in eyes; by far not the least of which is astigmatism, (wildly popular) which is when your cornea is not curved the same in all axis. (For example, your eyeglasses correction may need to be different vertically than horizontally.)
Astigmatism isn't going to lend well to this, would be my guess, but who knows maybe those wizards can make assymetrical fluid shapes.
Secondly, the size.. why make it big? Make it small like contacts (your eyes dialate only to 5 or 6 mm as an adult.) And put it close. Bizarre tiny eyeglasses is the ticket.
Re:Fixing Eyes With it (Score:5, Funny)
I don't know about that, I'm not that thrilled about mine. It's actually quite unpopular and not really likely to get voted 'most popular affliction' any time soon. On the other hand, it's rather common.
Re:Applications to Eyewear (Score:3, Insightful)
Re:Applications to Eyewear (Score:1)
Re:Applications to Eyewear (Score:1, Insightful)
The ones I'm thinking of was developed in particular for under-developed countries. Helpworkers can bring a whole set of glasses and easily and quickly adapt them on site without the need of expensive equipment.
Re:Applications to my eyeballs (Score:2)
Come on nano-tech!
New Scientist mentioned something similiar (Score:5, Informative)
There was an article in New Scientist a few weeks ago about a lense that changed it's focus in response to an electric current, iirc.
It was made of some plastic and I think the current changed the density of the plastic at some point in the structure in order to change the focus.
Of course, the aim was the same: "Make a lense without moving parts" - these guys must have developed a better solution because the Lense was very poor in the NS article.
Simon.
Stop saying "no moving parts", please (Score:5, Interesting)
Everyone keeps saying this. I looked at the diagram, and at least one part of the lens moves. That's a moving part, folks. Stop saying it "has no moving parts".
Now, here are some predictions:
Stop saying "no moving parts", please-Cateracts. (Score:1, Insightful)
Re:Stop saying "no moving parts", please (Score:5, Funny)
Thank you for showing us the light.
Re:Stop saying "no moving parts", please (Score:4, Interesting)
Actually, it's too small for consumer P&S cameras too if the picture is anything to go by, but it might be workable for disposables and video phones though. I'd hate to think what the accuracy of the lens will be in practice though - it's a fluid, so must have some vicosity, which means it's going to move about, which I would assume would impinge on image quality. Of course, there are other uses for lenses other than in cameras and spectacles where this type of lens might do very well.
BTW, your scaling for the EOS 10D is *way* off - the Philips lens is 3mm across according to the press release, most P&S camera sensors are around 8x6mm, although some are as low as 4.5x3.5mm - the 10D's is more like 23x15mm. As to the glass, for a 35mm camera format the glass would typically be in the region of 40mm-100mm in diameter depending on the type of lens and the location of the individual piece of glass in it.
Re:Stop saying "no moving parts", please (Score:2)
Re:Stop saying "no moving parts", please (Score:4, Informative)
The electrodes shouldn't have problems with corrosion. First, they don't even have to be in contact with the solution - the interaction is electrostatic and so a Teflon coating could be used. Furthermore, when working with a known solvent, corrosion issues are trivial. It's when making stuff that interfaces with the outside world and biological interfaces with all the associated uncontrolled variables that we still hit problems.
The curve should actually be as perfect as you want*. The interface is created by two imiscible liquids - while there will be some transient ripples from vibration, etc, the overall lens interface will be scratch free. It doesn't matter what the manufacturing quantities are - the lenses will be near perfect - the physics of the liquids will smooth out minor manufacturing defects. The only big concern would be defects in the electrodes (unlikely to be big enough in actuality to significantly affect the lenses) and making sure the correct volumes of both liquids are added. (again a trivial matter with modern liquid handling technology) Even if you do get some defects - its easy to correct. Simply automate an optical testing station where each lens has a light pattern run through it. A sensor looks for abberrations in the otpput light and calculates if the problem is fatal. If not, it calculates the necessary compensation to get proper optical performance. (eg: more or less charge on the elecgrodes for a given focus.) have an EEPROM associated with each lens that stores the correction value - problem solved.
* Note: your point holds in that the curve generated by the liquids doesn't form a perfect lens so you'll get hit with some nasty chromatic and spherical abberrations. These lenses definately WON'T be used for high quality optics.
Light loss should be a non-issue. I might be wrong here but surface reflection is primarily at air/liquid and air/solid interfaces because of the large refractive index mismatch. Here, all of the internal interfaces are liquid/liquid and liquid/solid interfaces. Reflective losses shouldn't happen, making anti-reflective coating unnecessary.
Color balance will only be an issue if the liquids absorb a particular color preferrentially. Since both liquids (at least from the pictures) appear colorless, this isn't an issue. The UV degradation you mention is an issue but simply putting a UV absorbing front coating on the lens should prevent degradation. Overall, the problem should be no worse than what one sees with low cost optics with plastic lens components.
I do agree that this lens won't be practical for anything but low-quality optics. The size is limited by the surface tensions and won't get much bigger than what is being demonstrated. Also, the lens shape is non-ideal and will give poor optical performance regardless of the size since it's shape is purely determined by the interacting surface tensions of the liquids.
What this lens will be wonderful for is low-cost disposable cameras, cell phone cameras and small security cameras where image quality isn't essential and cost/size are the determining factors.
A potential killer app is machine vision. A robot can easily compensate for the lens aberrations computationally. Furthermore, replacing the continuous ring electrode with a segmented one gives the ability to cahge the curvature
Stop saying "lense" please (Score:3, Informative)
It's "lens", plural "lenses". I don't care what your dictionary says [wsu.edu].
Skepticism? (Score:5, Funny)
Or developer with a finger...the size of a camera's lens!
You be the judge.
This is the last time I fall for the grotesquely-oversized-finger demonstration trick. Fool me once, shame on you; fool me twice...
Re:Skepticism? (Score:2, Informative)
No, it's not. If you get fooled once, it the fault of the person doing the fooling. If you're fooled twice by the same person, the fault is yours for falling for it again. Your way is completely backwards.
Re:Skepticism? (Score:1)
Re:Skepticism? (Score:1)
Re:Skepticism? (Score:2)
Re:Skepticism? (Score:2)
The press release (Score:4, Informative)
Philips' Fluid Lenses
Wednesday, 3 March 2004 21:40 GMT
Philips Research at the CeBIT exhibition is demonstrating a unique variable-focus lens system that has no mechanical moving parts. Suited to a wide range of optical imaging applications, including digital cameras. Philips' FluidFocus system mimics the action of the human eye using a fluid lens that alters its focal length by changing its shape. The new lens, which lends itself to high volume manufacturing, overcomes the fixed-focus disadvantages of many of today's low-cost imaging systems.
Press Release:
Philips' Fluid Lenses Bring Things into Focus
At this year's CeBIT Exhibition in Hannover Germany, Philips Research is demonstrating a unique variable-focus lens system that has no mechanical moving parts. Suited to a wide range of optical imaging applications, including such things as digital cameras, camera phones, endoscopes, home security systems and optical storage drives, Philips' FluidFocus system mimics the action of the human eye using a fluid lens that alters its focal length by changing its shape. The new lens, which lends itself to high volume manufacturing, overcomes the fixed-focus disadvantages of many of today's low-cost imaging systems.
The Philips FluidFocus lens consists of two immiscible (non-mixing) fluids of different refractive index (optical properties), one an electrically conducting aqueous solution and the other an electrically non-conducting oil, contained in a short tube with transparent end caps. The internal surfaces of the tube wall and one of its end caps are coated with a hydrophobic (water-repellent) coating that causes the aqueous solution to form itself into a hemispherical mass at the opposite end of the tube, where it acts as a spherically curved lens.
The shape of the lens is adjusted by applying an electric field across the hydrophobic coating such that it becomes less hydrophobic - a process called 'electrowetting' that results from an electrically induced change in surface-tension. As a result of this change in surface-tension the aqueous solution begins to wet the sidewalls of the tube, altering the radius of curvature of the meniscus between the two fluids and hence the focal length of the lens. By increasing the applied electric field the surface of the initially convex lens can be made completely flat (no lens effect) or even concave. As a result it is possible to implement lenses that transition smoothly from being convergent to divergent and back again.
In the FluidFocus technology demonstrator being exhibited by Philips Research at CeBIT 2004, the fluid lens measures a mere 3 mm in diameter by 2.2 mm in length, making it easy to incorporate into miniature optical pathways. The focal range provided by the demonstrator extends from 5 cm to infinity and it is extremely fast: switching over the full focal range is obtained in less than 10 ms. Controlled by a dc voltage and presenting a capacitive load, the lens consumes virtually zero power, which for battery powered portable applications gives it a real advantage. The durability of the lens is also very high, Philips having already tested the lens with over 1 million focusing operations without loss of optical performance. It also has the potential to be both shock resistant and capable of operating over a wide temperature range, suiting it for mobile applications. Its construction is regarded as compatible with high-volume manufacturing techniques.
(A) Schematic cross section of the FluidFocus lens principle. (B) When a voltage is applied, charges accumulate in the glass wall electrode and opposite charges collect near the solid/liquid interface in the conducting liquid. The resulting electrostatic force lowers the solid/liquid interfacial tension and with that the contact angle q and hence the focal distance of the lens. (C) to (E) Shapes of a 6-mm diameter lens taken at different applied voltages.
Prototype FluidFocus lenses
Photos courtesy of Philips
A Glimpse (Score:2, Interesting)
Re:A Glimpse (Score:1)
From The Dune Encyclopedia: Oil Lens (Score:3, Informative)
The lens diagrams are wrong. (Score:1, Interesting)
The first lens has a positive magnification, and the second a negative magnification. The light rays drawn on the diagrams are reversed.
Others should be able to confirm this.
Re:The lens diagrams are wrong. (Score:3, Insightful)
No, it is probably right (Score:3, Informative)
So, if light is faster in the blue liquid than in the brown one, the light-rays would move as described.
Re:The lens diagrams are wrong. (Score:5, Informative)
you see that there are two fluids: brown one on top and a blue one on the bottom. If you remember Snell's law [wolfram.com] (ray bends towards the normal in the denser medium), you can conclude from the picture that the 'brown' fluid has a higher refractive index than the 'blue' fluid. The left picture thus resembles a hollow/concave/negative lens and the right picture resembles a convex/positive lens. Of these the positive (on the right) can be used to form a real image (one you can capture on a CCD or a retina), whereas the negative only forms a virtual image [asu.edu].
A colleague of mine did his internship at the group that invented these and my boss still works part-time at Philips.
Anybody remember these from Dune? (Score:5, Funny)
Just another instance of science fiction authors' jobs getting harder, I guess.
Re:Anybody remember these from Dune? (Score:5, Insightful)
Re:Anybody remember these from Dune? (Score:4, Insightful)
Re:Anybody remember these from Dune? (Score:1)
Seriously though:
First thing I thought when reading this article was: "Now this is what patents are all about".
A company that innovates like this deserves to be the only one that may use its' invention and be protected from other companies that would otherwise just copy the specs and immediately compete on the same level.
Re:Anybody remember these from Dune? (Score:2)
cool but i wonder (Score:4, Interesting)
I also noticed that their prototype is extremely small - wouldn't a bigger one be subject to gravitational pull / buoyancy (in respect to eachother) of the liquids depending on lens orientation - and therefore causing a distortion to the optical surface?
Re:cool but i wonder (Score:2, Insightful)
I think that's the point--they're targetting small camera applications: mobile phones, PDAs, keychain digital cameras, clandestine surveillance cameras and such.
Why are the lenses small? (Score:4, Insightful)
Prolly not. The real issue is that the smaller the lenses, the more of a role surface tension takes towards creating a uniform surface. Boundary layers between fluids always have a tendency to bow out in one direction or the other. But that "skin" is just half the thickness of one molecule plus it's range of interaction with the surrounding ones. For water, remember your Van Der Waals forces, kids.
In a one centimeter wide tube filled with water, this phenomenon is obvious and dominates the behavior of the interface. In a one *meter* wide tube, everything from little wavelets from vibration (!) to any impurities to, oh, btw GRAVITY[1], will tend to randomize the shape of the interface.
In udda woids, the bigger the surface area, the more random, or at least nonuniform the shape of the "lens".
Getcherself a copy of good ol' Prandtl&Tietjens (Fundamentals of Hydro&Aerodynamics). Your life will never be the same.
[1] It blows my mind that *nobody* on this thread has yet commented on the tendency of gravity to deform such lenses. Gack! Have *any* of you done the thought experiment instead of just believing what you read?
The Phillips device has a second fluid. I would assume in part this is to address that. Betcha that the indices of refraction are very different but the densities are exactly the same.
Rustin
Re:Why are the lenses small? (Score:2)
I'd guess that the front and back surfaces of the len
Re:cool but i wonder (Score:1)
News? (Score:5, Informative)
The News here is that the Philips lens can be focused by an electric field with no part moving other then the lens. The size of their prototype is tiny; IMHO they need at least to triple the size of it to make it useful for digital cameras.
Re:News? (Score:4, Interesting)
Another fascinating application mentioned in NewScientist's coverage of this stuff is variable zoom security cameras. A security camera could zoom and focus selected portions of the field of view without needing to tilt or swivel the housing. Imagine a kind of moving fisheye effect within the rectangular frame of view. You bolt one of these very cheap cameras to the wall with a very wide field of view and then your operator/software invisibly controls the lens to follow objects closely. Awesome.
I think Frank Herbert beat them to it. (Score:1, Redundant)
I wouldn't be surprised if any authors pre-date Herbert with coming up with liquid lenses. Mr. Herbert is just the one that came to mind.
Artificial Eyes? (Score:5, Interesting)
Re:Artificial Eyes? (Score:1)
Re:Artificial Eyes? (Score:1)
Seen the GITS2 trailer? (Score:2)
Bumpy Car Ride? (Score:3, Insightful)
Re:Bumpy Car Ride? (Score:2)
Yeah, two thoughts. First, given the size of the lens, the surface tension of the fluids, and the strength of the electric field, this might or might not be an issue. Second, most current cameras don't perform very well in "nonstable environments". Some cameras have compensating mechanisms (like my now-classic Olympus 2100 Ultra-Zoom), but there's only so much that can be
New spin on something older (Score:4, Informative)
Re:New spin on something older (Score:4, Informative)
Re:New spin on something older (Score:2)
Electrowetting (Score:4, Funny)
Cheers
Stor
Re:Electrowetting (Score:1)
...
really, I don't!
...
what's everyone looking at?
Good for photography...maybe (Score:5, Interesting)
For single lens cameras, no coatings are not that big a problem.
For multiple lens cameras, it can lead to a lot of chromatic aberations.
If these oil lenses can accept liquid optical layers, look out Karl Zeiss.
It's an eye! (Score:3, Funny)
How ironic... (Score:1, Offtopic)
Folks (and note, in particular, "Arse(sic) Technica"): please stop doing this! You're not being 'cool' - you're just making your text harder to read.
Old news (Score:3, Interesting)
Flying Image Quadroids (Score:1)
Electrowetting (Score:5, Funny)
Why not a spinning liquid lens? (Score:3, Interesting)
Hermetically closed underwater camera!!! (Score:5, Interesting)
So I have always dreamt of a hermetically closed camera. You could fill it with a liquid (oil?) to reduce the pressure stress on the enclosing. (This is what current scuba computers do.) By using a digital camera, you don't have to open the camera to access the film. The problem so far has been how to construct a zoom lens since these vary in volume. This kind of lens seems to fix that problem!
New posibilities (Score:3, Insightful)
Frank Herbert: "Dune" (Score:1, Redundant)
Liquid Lenses? (Score:2)
* I don't actually buy the church example, but I just thought I would troll for karma anyway.
underwater camera (Score:1)
Re:underwater camera (Score:2)
Seen it in use in Africa (Score:3, Informative)
One idea for using those (Score:5, Insightful)
Re:One idea for using those (Score:5, Informative)
Re:One idea for using those (Score:2)
the lens is not the reason why this is not possible
Re:One idea for using those (Score:2)
- "Imagine a picture of an object 10cm from you where both that object and the background is sharp."
This is just Depth of Field [mtu.edu] (DOF). It is largely a function of aperture size. As the aperture shrinks, the DOF expands.Re:One idea for using those (Score:3, Interesting)
Philips rock (Score:2, Informative)
at this company and wonder about their corporate culture know this... Philips combine technical excellence with an easy going attitude that encourages invention and freethinking.
They pay good wages and have excellent facilities. I was at their Eindhoven unit in 1995
for about 6 months. Even though I was an outsider brought in on consultancy, younger
A brave new world of imaging! (Score:5, Interesting)
This makes a lot of things possible that would have been prohibitively expensive, mechanically improbable, or optically restrictive. A small lense with fast focusing, which is high quality, shock resistent (this would depend on oil viscosity and lenses size), and remarkably cheap to manufacture in large numbers would revolutionize;
* Robotic vision,
* Consumer electronics,
* Security and Research imaging,
* Medical Imaging, and Lense Replacement.
You could cover a robot with cheap eagle-eye imaging devices, create a central imaging system that sews all the images together to produce an ultra-highres 360 degree whole world views. This machine would literally have eyes in the back of it's head. Give the critter broad spectrum vision, and spectrospopic analysis, and this robot could be used for anything from public safety, to mineral evaluation for mining. If you're going to buy a robot, make sure it has "Phillip's whole world vision(tm)".
This makes disposable highres digital cameras and camcorders totally practical. It makes low end devices possible, products for tens of dollars or less, that have the optical features you would expect to find in products that now cost hundreds of dollars. This is especially true if you combine glass element(s) to the lens. You get the power and optical benefit of a glass front lense, a large optical aperture for light gathering, with simple focus and zooming capabilities provided by liquid lenses. A superior lense with a huge list of advantages. Sign me up!
Now that you have a high quality cameras selling for $10.00, you can put them anywhere and everywhere. Imaging for a whole host of purposes becomes ubiquitous (orders of magnitude more prevalent than today.)
Beside giving medical devices better vision, replacing the lense in the human eye, with one that is for all intents and purposes perfect, would be a godsend to millions of people with cataracts, degenerative lense desease, and missing or injured lenses. In the end, this might become so common place, that when you get to that age where folks noadays begin buying multifocal glasses, our descendents will simply get a super lense implant, and have bionic visual abilities that we can only imagine. Would you trade your eyes in for one's that gave you superwide angle and telescopic capabilities? Oh, and for those folks with astigmatic trouble, one could circle the inside of the lense barrel with panels, and apply differing voltages to the panels so as to create a lense shape consistent with any corneal asymetries. This would be the hot new product among the rich and graying!
Genda
Aberations (Score:2, Interesting)
Aberations aside, its always cool to se new technology emerge in the field of visual optics. The field of optical science is realy realy old [st-and.ac.uk] and still
Re:Aberations (Score:2)
Old news (Score:1, Informative)
Anyone need prior art ?
Re:Old news (Score:2)
The cheap glasses are basically a pair of tensioned water balloons in a cheap frame. (50's fashions appear to be 'in' for the third world, I guess.
Don't we have that already? (Score:3, Funny)
You know the ones, a few lagers and you generally have a better appreciation of the fairer sex.
;-)
Freezing? (Score:2)
Also I wonder how gravity affects these in reasonable sizes; seems it would tend to pull the lens downward unless the two solutions had exactly the same specific gravity.
Nit: Singular of "lenses" is "lens". I don't know what a "lense" is but I'd pronounce it "lens-ee" if I had to guess.
What A brilliant Idea and I Should Know. (Score:4, Informative)
Of course I designed it for different uses (mostly diagnostic) and had a few added features that they didn't implement. Gonna have to look at their patents and take a gander at the claims.
I wonder if I should sue.
What's *really* funny is that from what I know, DoD may already have patented my beastie for use in SDI, with or without NASA permission.
Hmmmmm . . . . .
Rustin
Military Applications (Score:2, Interesting)
Not the first... (Score:3, Informative)
Liquid Mirror Telescopes (Score:2, Informative)
Where I want such lenses: car headlights (Score:2, Interesting)
timothy
Re:Super DVDs (Score:3, Insightful)
Philips is the inventor of the CD, and plays an important role in the development of DVD and its successors. Now where could somebody use a tiny, focusable lens without moving parts? Multi-layer optical drives, both player and recorder is certainly a valid answer.