Wearable Tech World Feature Article
August 02, 2013

Eye Wonders - Wireless Contact Lens Displays and Zoomable Contacts


Nanotechnology, microelectronics and our ongoing ability to make electronics ever smaller are leading us to all sorts of cool wearable tech. Most of that technology is currently wearable in some form or fashion though smart fabrics, under the skin sensors and direct skin-attachable tattoos (miniature wireless connected grids and other such components) are beginning to make wearable tech almost invisible.

Other new wearable tech is a bit more visible - Google Glass for example, or Max Virtual's amazing bone conduction audio hat that is able to restore hearing based on certain types of hearing loss. Finally we have tech such as Second Sight's Argus II Bionic Eye, which can restore vision to those who've lost it. It is all fascinating stuff, but perhaps the one thing that has long intrigued us the most when we fall into our sci-fi mode is the ability to do something extra with our vision.

A robot eye that can zoom something in from afar, or a robot eye that provides internal views of computer screen displays (early “Terminator” movies anyone?) have always been sci-fi staples. And they've always captured our imaginations - especially when they are disguised as parts of cyborgs that look human and one can't tell there is something special about those eyes. This sci-fi is what we really want. Such things as Google Glass begin to move us a bit towards our goal, but Google Glass is still more a trendier “Tron” extrovert tech than an invisible cyborg feature.

But hold on to your bone conduction hats! It appears that the invisible cyborg features we really crave are in fact just around the corner if recent breakthroughs are to be believed - and they are. As it happens, over the last several weeks technologies have appeared in the form of contact lenses that provide wireless screen displays and zoomable capabilities. Before getting too excited, we need to underscore that these technologies are still in the early stages of development, but they've both reached the point where we can see realities just down the road.

Zooming In

Let's begin with contact lenses that are actually able to zoom in and out. They take the form of a 1.17mm thick pair of contact lenses that are actually able to deliver up to 2.8X magnification for the person wearing them. The lenses have been developed by an international collection of researchers - among them Eric. J. Tremblay, Igor Stamenov, R. Dirk Beer, Ashkan Arianpour and Joseph E. Ford. The key here is the thickness that has now been achieved - or rather we should say the lack of thickness.

Previous efforts have produced contacts in the range of 4.4mm thickness - which, though functional to some degree made wearing them essentially impractical. Other research has focused on lenses that are implanted into the eye directly - and quite honestly this is not an approach that we would be keen to "give a shot." Below are several photos that show the actual lens, along with what the lens covers in relation to the eye itself. That third image shows an actual-sized human eye and the team uses it to demonstrate how the contact lens actually works.



 

We're hard pressed in the space we have available to describe how the lens works, but if you happen to be an amateur astronomer who has used one of those impressive looking, mirror-based telescopes or a semi-serious photographer who has used a mirror-based zoom lens (we did once fall into this category ourselves) and you have a sense of how these work, then you will begin to get a sense of how the zoomable contact lens works.

The contacts use patterned aluminum mirrors that reflect incoming light rays four times, magnifying the resulting image each time, and also correcting for chromatic aberrations in the process. To accomplish this at the level of a contact lens is impressive to say the least. The final stage of the process is to then project the now magnified image along the edge of the wearer's retina.

For those among us who love to read technical papers, the actual research paper, written by the researchers noted above and unimaginatively titled "Switchable Telescopic Contact Lens," is directly available for reading online. The paper is supplied with a wealth of great images we have not reproduced here.

As shown in the images above, the lens provides a clear middle section that allows direct, unmagnified light through. The telescopic mechanism sits around that middle section. Each lens is further equipped with a polarizing filter in front of the clear portion (refer to the paper itself for diagrams of this). The polarizing filter is critical to the process and allows the wearer to switch between zoomed and unzoomed views depending on what polarized glasses are used. Provided below are three images that show the zoom capability and what a wearer would see.

If you do read the research paper you will of course discover that these contact lenses haven't simply been built to give people with otherwise normal vision the ability to really go cyborg on a whim. As with the Argus II bionic eye noted earlier the contact lens has been designed to help people with real world medical problems.

In this case, the goal is to help people with age-related macular degeneration (AMD) overcome vision loss due to the disease. Magnification is the usual means by which people deal with AMD, but the means for doing so is typically bulky, requires head movements that are often inconvenient and tends to be cosmetically unappealing.

That said, we can certainly dream about a day telescopic vision becomes a real option for many of us.

For the Terminators Among Us

Perhaps you know the name Babak Parviz. He is one of the original inventors of Google Glass and as far as we know he is also still invested in the project. But Parviz works on a variety of projects and one of them is focused on taking the possibilities represented by Google Glass and moving them all much closer to the eye itself. In a sense, the seemingly sophisticated Google Glass is nothing more than a very crude representation of what we will ultimately be capable of, and Parviz has now taken a significant step forward toward defining what that capability may prove to be.

Not that he's done it by himself. Parvis has been leading a team of U.S. and Finnish bioengineers - among them A. R. Lingley, M. Ali, Y. Liao, R. Mirjalili, M. Klonner, M. Sopanen, S. Suihkonen, T. Shen, B. P. Otis and H. Lipsanen. The researchers come from the Department of Electrical Engineering and the Department of Ophthalmology at the University of Washington, and from the Department of Micro- and Nanosciences at Aalto University in Espoo, Finland. These folks are all co-authors of the research paper we're basing our coverage on, also unimaginatively dubbed "A Single-pixel Wireless Contact Lens Display."

The paper details building a wearable contact lens that contains an embedded wireless antenna, a radio receiver, the necessary control circuitry, and an LED display, albeit at this point an LED display consisting of exactly one LED - or pixel. In and of itself, if what Parvis and his team were building was the size of an iPhone, there would not be all that much magic to it. And in fact the likes of Google Glass and the new Vuzix M100 are the current state of the art on heads up smart glass capabilities that this technology will someday replace.

But imagine all those electronics packed into something the size of a contact lens - not only in terms of the diameter involved but also in terms of the real-world thinness of what the lens must be. It makes Google Glass look positively out of the dark ages. Shown below is the contact lens itself - though perhaps at this point we should refer to it as a wearable display device.

Admit it - it certainly looks cool in a secret agent sort of way. But don't expect any secret agents to demo it just yet. The team of researchers has managed to effectively demonstrate the contact lens in action - though some of us might consider it a bit of an oddball demonstration. Why? Because the team has chosen to work with rabbits on the project. No doubt there are probably a few "rabbits eating carrots and having good eyesight" jokes to be had here.

The image below shows a more detailed view and what the current version looks like on our secret agent rabbit - but it isn't hard to imagine what it might look like if a human were wearing it. Keep in mind just how small the contact lens really is - that is the magic here. The team claims that no rabbit eyes were harmed in testing the lens - a good sign.

In the current design, an external battery transmits power through RF to the antenna that runs around the edge of the contact lens. Obviously the antenna requires positioning such that it doesn't get in the way of the wearer's direct and peripheral lines of sight. The tiny IC that is shown combines a 450 pF (Picofarad) capacitor (for the electrical storage) and a tiny 130nm CMOS processor - the IC serves to aggregate the supplied power through the antenna and then uses it to light up the single LED.

The contact lens itself is quite interesting in that it is based on the Fresnel lens. If you don't recall what a Fresnel lens is from your high school science optics classes, it is a lens design that greatly reduces thickness. The problem with Fresnel lenses is that the design also reduces image quality.

We're not yet sure we understand how a Fresnel design will deliver the necessary image sharpness a contact lens needs to deliver or how exactly the design will focus the LED for individuals, but no matter. Perhaps ironically, the Fresnel lens has its roots in lighthouses - where the design allowed for huge yet very lightweight glass lenses to focus light. We've gone from completely massive to completely miniaturized.

There is not much one can do with a single pixel of course, although we can think of many scenarios where a single LED is used to alert us to something - new e-mail or a new message is waiting, for example. How about something totally non-tech - say using a level in house construction and getting that LED signal when you have something perfectly plumb?

No, it is not a Terminator display yet - though keep in mind that those early “Terminator” movies were showing us now-ancient DOS screens! But sometime off in the future, when Parviz and his research team are ready to move to human trials, that LED will no doubt have been stepped up to a more robust display. We can say that the team has plans in hand to project multiple pixels onto a single contact lens by using an array of micro-Fresnel lenses as its next step in display improvement.

That leaves one last question. Where does the power come from? Whatever device is used to generate and transmit the power must be quite close to the lens itself in order to make use of RF power distribution. Let's say that various wearable tech companies will have delivered ways to generate power through some sort of motion-based sensors - the how and why don't matter - but let's assume it is possible.

One isn't going to wear a contact lens that requires some sort of external and bulky power appendage. Perhaps an under the skin, embedded battery would suffice. Use your imagination - by the time we're ready for human trials of the lens, tiny bendable batteries and wearable tech power generation will be available.

That leaves one last question: Are you ready to take the rabbit's place?




Edited by Alisen Downey




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