For Silicon Valley entrepreneur Philippe Kahn, necessity truly is the mother of invention.

The 54-year-old, French-born technology innovator has founded four companies since coming to the U.S. in 1982. All were based on technology developments to fill a need, often personal.

While waiting for the birth of his daughter Sophie in June 1997, Kahn invented the first camera phone for instantly sharing photos. Others had worked on marrying the cell phone and digital camera, but Kahn concentrated on what turned out to be the killer application of sharing photos electronically.

"The bottom line is that the camera phone is not just a camera and a phone. The camera phone is an instant share infrastructure with a camera on the phone," Kahn said in a recent interview. "The ability to share instantly is really the key."

The camera phone helped fuel the citizen journalism trend because users could take photos and video wherever they went and share those with others instantly. News events from terrorist bombings and police brutality to celebrities behaving badly have been captured and shared using cell phone cameras.

Kahn came up with the idea of the camera phone infrastructure while at the hospital when his wife, Korean-born entrepreneur Sonia Lee, was in labor. He wanted a way to share photos of his new baby with friends and family around the globe.

He had a notebook computer, digital camera and cell phone with him. He sent his aide to a RadioShack store to buy a soldering iron, wire and other supplies and built a working camera phone at the hospital.

He also created the server infrastructure to automatically post pictures to a Web site and send links to people on his e-mail list. It was the first case of photo blogging, he says.

Smile

Kahn says he created the camera phone setup for fun. It wasn't until friends responded with amazement over what he did that he decided he could make a business out of it.

Kahn founded LightSurf Technologies in 1997 to make instant visual communications possible for everyone. LightSurf developed an end-to-end system for instant wireless digital photography. The system included photo-enabled mobile devices, wireless acceleration technology and back-end imaging servers.

"I don't sit around and say, 'I want to build something to make money,' " he said. "I'm a technologist and I create new things. That's what I do."

LightSurf is one of four companies started by Kahn. VeriSign bought LightSurf in 2005 for more than $300 million.

His advice to young people interested in technology and business is to focus on innovation to change the world for the best. Good things follow from that, he says.

Kahn founded his first company, Borland, a provider of software development tools, in 1982. Kahn led Borland for 12 years before being forced out in a dispute over the company's direction.

He then started Starfish Software, which made software for synchronizing wireless and wired devices, in 1994. Motorola bought Starfish for more than $250 million in 1998 and later sold it to Nokia.

Kahn founded his latest company, Fullpower Technologies, in 2003. It's still in stealth mode and Kahn won't provide specifics on what it will offer. The company's Web site says Fullpower is focused on the convergence of life sciences and wireless technology. Kahn expects to reveal details about the company in September.

"I build things that I think are exciting from a technology standpoint and will help make life easier, simpler and better for people," Kahn said. His businesses all have grown out of the desire to create something to meet a need.

The genesis behind Borland was the need for good software development tools in the early days of the personal computer. Starfish was born out of Kahn's frustration with having to input data like contact lists into more than one device, such as a mobile phone and PC.

Kahn says he's always looking for a new challenge.

"I don't think about the past. I'm focused on the next adventure," he said.

Kahn was educated at the Swiss Federal Institute of Technology, or ETH Zurich, in Switzerland, where he received a master's degree in mathematics. As a student in 1973, he developed the software for the Micral, the earliest commercial, non-kit personal computer based on a microprocessor.

Kahn came to the U.S. from France on a tourist visa and with few possessions. He wanted to work for Hewlett-Packard, which he considered the best technology company at the time. The opportunities in technology were much greater in Silicon Valley than in Europe, he says.

He didn't have much money, but he had skills and confidence. So he took the risk to move overseas.

"I always knew that it was just a matter of someone giving me a shot," Kahn said. He knew he needed only 10 minutes to convince a company he would be an asset.

He was right. HP hired Kahn on the spot. But three days later he lost the job because he didn't have a green card. However, HP hired him as a consultant. Kahn got his green card in 1986 and later became a naturalized U.S. citizen.

The going was tough early on in the U.S. He sent money back to Europe to support his wife and two children while he tried to make a home in Silicon Valley. It took a year to bring his wife and children over.

Kahn chalks up a lot of his success to plain old hard work.

In high school and college, he felt other students were smarter than he was, so he had to push harder.

"I always felt that if I worked twice as hard as they did, I could do better," Kahn said.

He says he keeps trying to improve himself, studying and researching the latest technology findings.

"It's annoying to people that I will buy every college physics and mathematics book and read through them and be up-to-date," Kahn said. "I think it's so sad that people go to college and most of them stop learning after college."

Time To Study

It's even more important to study after your formal education because the base of knowledge just gets bigger and bigger, Kahn says.

"I make it a point to spend an hour a day to do that," Kahn said. "By the end of the day I always ask, 'Did I do that?' even if it's in chunks of 15 or 20 minutes."

Sometimes that means reading articles or papers in the bathroom, he says.

Kahn has the same discipline with recreation. He practices the flute daily. Kahn studied classical flute and musicology at the Zurich Music Conservatory in Switzerland.

BY PATRICK SEITZ