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UC SAN DIEGO INVENTOR RECEIVES NATIONAL
ATTENTION FOR TECHNOLOGICAL BREAKTHROUGH

Editors Note: Images available at http://www.soe.ucsd.edu/events/9_15lens_pics.html

Daniel Hartmann, an electrical and computer engineering graduate student at UC San Diego’s Jacobs School of Engineering has invented a new line of high performance, low cost polymer microlenses. These tiny optical components may be used as building blocks inside next generation computers and flat screen televisions. Hartmann was one of six first place winners at the 2000 Collegiate Inventors Competition, sponsored by the National Inventors Hall of Fame (http://www.invent.org/). He received a cash award of $20,000 for his creation.

Microlenses, which direct and focus light beams, are currently being used in optical switches for routing signals in optical communication systems. But in part, because costs can range as high as $20,000 for a single array of lenses, microlenses have found limited use in consumer products. As more and more hi-tech applications emerge, there is an increasing need for cost-effective microlens technology. Under the direction of Electrical and Computer Engineering professor Sadik Esener and researcher Osman Kibar, Hartmann has created an elegantly simple fabrication technique that could bring the costs of microlenses down to earth.

“Our process for creating an array of microlenses requires very little machinery, and no heat,” says Hartmann. “Using a principle called the hydrophobic effect, we simply coat a piece of glass or silicon with RainX, a compound that makes the glass resistant to liquid. Then we etch out our pattern for the lens array. After that, we dip the glass into a polymer solution. The solution sticks to the areas that have been etched out and naturally forms small caps of liquid that become lenses.”

Even though the use of the hydrophobic effect to make microlenses is not new, Hartmann and his colleagues were the first to demonstrate the useful, practical fabrication of low-cost microlenses using the technique. As Hartmann explains, “We have characterized, theoretically modeled, and optimized the lenses constructed. We have found that we can reliably and cost-effectively fabricate lenses in a variety of shapes and sizes ranging from 2 to 500 millionths of a meter in diameter and with excellent uniformity and reproducibility.”

Hartmann expects manufacturers will be able to use such low-cost microlenses to develop ultra-fast computers. Such lenses can be used to make optical-interconnects, which could replace traditional electrical interconnects between chips and other components. Microlenses could be used to redirect light beams through optical fibers, or even through midair, bridging the gap between a transmitter and a receiver.

Another application area is flat panel screens for televisions and monitors (e.g. active-element displays). Today’s liquid crystal and plasma flat panels only produce an adequate picture when viewed straight-on. Microlenses can effectively direct light received from active pixels in a very tight space to create a full picture for the viewer, from any angle. The screen can be flat, and the light directed and collimated in a very small area because there is no longer a need for a cathode ray tube, magnets, electron gun, or evacuated chamber found in traditional television sets and monitors.

Hartmann and his colleagues continue to develop this microlens fabrication technique. Using a variant of the fabrication process, they have constructed lenses self-aligned to optical fibers and integrated with micro-electro-mechanical-systems (MEMS). UCSD has a patent pending on the technique.