Micro Machines and Opto-Electronics on a Contact Lense
Mathematician and SF writer Vernor Vinge has a thing for contact lenses. Wearing the special contact lenses he describes in his fiction –- coupled with computers in clothing and locational sensors scattered everywhere –- his characters see a constant stream of text and virtual sights overlaying the real world.
Fiction now meets reality with prototype contact lenses developed by Babak Parviz at the University of Washington, in Seattle. Dr. Parviz’s prototype lenses can be used as biosensors to display body chemistry or as a heads up display (HUD). Powered by radio waves and 330 microwatts of power from a loop antenna that picks up power beamed from nearby radio sources, future versions will also be able to harvest power from a cell phone.
In his early 2008 lab tests, rabbits safely wore contact lenses with metal connectors for electronic circuits. The prototype lenses contained an electric circuit as well as red light-emitting diodes for a display. The lenses were tested on rabbits for up to 20 minutes and the animals showed no adverse effects. Here’s a video of Dr. Parviz explaining the design of the lenses:
Fitting a contact lense with circuitry and power is a complex matter. The circuitry has to be transparent so as not to annoy the wearer. Also, techniques had to be developed to deal with the temperatures and chemicals used in large-scale microfabrication so that the polymer material used by the contact lenses is not ruined.
"Conventional contact lenses are polymers formed in specific shapes to correct faulty vision,” says Dr. Parviz. “To turn such a lens into a functional system, we integrate control circuits, communication circuits, and miniature antennas into the lens using custom-built optoelectronic components. Those components will eventually include hundreds of LEDs, which will form images in front of the eye, such as words, charts, and photographs. Much of the hardware is semitransparent so that wearers can navigate their surroundings without crashing into them or becoming disoriented.”
The prototype includes a lense with one LED powered wirelessly with radio frequency (RF). “What we’ve done so far barely hints at what will soon be possible with this technology," continues Parviz.
The power for the lense comes through an antenna that collects incoming RF energy from a separate portable transmitter. Power-conversion circuitry provides DC power to other parts of the system and sends instructions to the display control circuit. The display –- at the center of the lense –- can consist of multiple LEDs that turn on and off. Their transparency is modulated by the control circuit.
Dr. Parviz’s contact lenses offer the possibility of something akin to the augmented reality and graphical display effects used in the movie Iron Man
An energy-storage module such as a large capacitor can be connected to a solar cell to provide a power boost to the lense. A biosensor samples the surface of the wearer’s cornea, performs an analysis, and then provides data to the telecommunication module to transmit to an external computer. Such contact lenses will obviously spend hours touching the human eye. Parviz’s team wants to explore the depth and breadth of information that can be captured by wearing the contacts – for example, diabetics can monitor their blood sugar levels. The lense can sample the information obtained from the eye’s surface and display the results in front of the eye as a HUD.
The first HUDs were used in the military based on static gun sight technology for military fighter aircraft with a ring and dot of light called the "pipper," which projected onto the clear glass in front of the sight. HUDs soon were developed to display computed gunnery solutions — using aircraft data such as airspeed and angle of attack — to greatly increase the accuracy pilots could achieve in air-to-air battles.
Today’s fighter and space shuttle pilots are heavily dependent upon HUDs to provide up-to-the-second real time information. Here’s the view of an F16 HUD during a 5-minute flight (the real thing, not simulated, so hang on to your lunch):
Dr. Parviz’s contact lenses offer the possibility of a much more personal HUD, something akin to the augmented reality and graphical display effects used in the movie Iron Man. Here’s a short video (courtesy of Andrew Kramer’s Video Pilot web site) showing a somewhat futuristic vision of the types of graphical information displays that might possible with such contacts lenses:
When you combine Dr. Parviz’s contact lense technology with avatars and virtual worlds, you start to grasp Vernor Vinge’s vision of the near future. With your contact lenses in place, you chat with a distant friend’s quite lifelike image strolling at your side, and adjust the scenery to your mutual taste — adding, say, a raucous nightclub or a serene Zen temple — at the same time that you’re each privately IM’ing your friends and browsing the Internet, much as avatars do today in Second Life.
Given the recent research into the dangers of text messaging while driving, this type of iPhone-on-steroids distraction might seem extreme. Contact lenses as replacements for smart phone displays — even to monitor blood glucose levels — might best be done while not operating heavy equipment. "The true promise of this research is not just the actual system we end up making, whether it’s a display, a biosensor, or both,” comments Dr. Parviz. “We already see a future in which the humble contact lens becomes a real platform, like the iPhone is today, with lots of developers contributing their ideas and inventions. As far as we’re concerned, the possibilities extend as far as the eye can see, and beyond.”