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Takahashi: New idea? Electricity researchers work on cutting the cord

By Dean Takahashi

Mercury News

Article Launched: 04/19/2007 07:12:46 PM PDT

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Who ever heard of wireless electricity? Seems impossible.

I wouldn't believe it if I hadn't seen a demo myself at PowerBeam, a Sunnyvale start-up. The technology they showed off makes me believe that big, revolutionary ideas are still possible in Silicon Valley - even after decades of innovation. Don't close down the patent office yet.

PowerBeam co-founders David Graham and Xiaobing Luo showed me how they could power up a little toy with a spinning fan without using either batteries or a wired power source. They can do so with an invention that seems suspiciously simple.

They pointed a laser beam at a solar cell. The solar cell collects the light energy from the laser and converts it into electricity. Light in, electricity out.

Then the electricity travels from the solar cell into the device. They call it an "optical power beam."

It's the same principle that powers your pocket calculator with a solar cell. But in this case, PowerBeam gets a lot more electrical power from a laser as far away as 65 feet.

In a patent application, PowerBeam says it can produce much more electrical power than other methods because it has tamed a dangerous laser. It uses a powerful laser of the sort that could cut through your hand, but it has integrated a safety system, allowing it to channel a lot of energy into the solar cell.

I can't be a good judge about the PowerBeam technology (other than vouching that the demo worked). But I love the vision. I believe
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that someone who pioneers this market will find a bonanza.

Graham envisions someone using a laptop without plugging it in at all. You could, for instance, sit at a cafe or in the middle of a hotel ballroom and draw power from a light fixture above the center of the room. A laser atop the light fixture would seek out any solar receptor in the room with help from a detection system, such as a camera. When it finds it, the laser would concentrate its light beam on the laptop's solar cell.

The size of the solar cells needed would vary based on how much power is needed. A cell phone could be charged with a solar cell the size of a silver dollar, says Graham. For a laptop, the cell would be bigger and be mounted as a pad on the laptop's cover. If PowerBeam systems improve and became popular, you wouldn't need batteries for your laptop as you travel.

Another application is security cameras, which often need to be placed where it's not convenient to string an electrical cord. A security camera can run on just four watts, which Graham says his device can produce using a very small solar cell. Still another application is to use the PowerBeam system to connect high-end audio speakers anywhere in a room without having an unsightly electrical cord attached to it.

It's a big dream for a little company. PowerBeam is just a two-person company in Sunnyvale's Plug and Play Tech Center, a building that houses scores of start-ups. The company still has perhaps two years or more before it gets a product on the market. But Graham says the company has filed for patents on the basic invention and is now talking to potential partners about applications.

"We produce wireless electricity," Graham says. "Think of us as PG&E. Our partners will do interesting things with it."

As for competition, it isn't hard to find patents for "wireless electricity." In the early 1900s, radio pioneer Nikola Tesla unsuccessfully tried to commercialize a wireless electricity invention. Many wireless power solutions aren't really useful because of problems relating to how much power they can transfer over distance.

Last year, a research team headed by Marin Soljacic at the Massachusetts Institute of Technology said it could transfer electricity wirelessly using a concept called electromagnetic resonance. Powercast, a Pennsylvania start-up, says it has a safe wireless power system that uses radios to transmit power. The company says it will be used in lots of devices by the end of 2008. And another start-up, WildCharge, is preparing to start selling a pad that wirelessly charges cell phones that are placed on top of it.

PowerBeam's Graham says his solution uniquely combines a powerful laser with a safety system.

This isn't his first start-up. He sold a previous software company to National Semiconductor in 2003 for an undisclosed sum. After a year at National, he left to start something new. He dreamed up the PowerBeam idea about two years ago and later recruited Luo, a former National colleague who is an optical scientist.

The two men were able to get a short-range demo working in December, and I saw it work across the width of a sizable room. The company is self-funded so far, but it plans to raise venture money. The solution eventually has to solve somebody's problem, and it has to be inexpensive.

"About 10 percent of this is science," Graham says. "The rest of it is engineering."