RADIO FREQUENCY IDENTIFICATION Inventor's idea from the 1970s is gaining widespread use today



Some believe the RFID chips could wipe out bar codes.
KNIGHT RIDDER NEWSPAPERS
Office workers who wave a key card to unlock a door should think of Charles Walton.
One of Silicon Valley's unsung inventors, Walton's patents on radio frequency identification, or RFID, spawned those electronic door keys. Now the technology Walton pioneered in the 1970s and 1980s is poised to change the way billions of products are tracked.
Prodded by Wal-Mart and the Pentagon, manufacturers soon will be tagging everything from diapers to combat boots with RFID chips. The chips transmit information about products' location and use over radio waves to a central computer. Libraries are using RFID to keep tabs on books while hospitals embed radio chips on pharmaceutical bottles to makes sure drugs are not misused. A Barcelona nightclub scans RFID chips implanted under patrons' skins when they want to pay for a drink wirelessly.
For Walton, industry's embrace of RFID is bittersweet. Back in the 1970s, the bar code was a 25-cent solution that beat out Walton's $1.75 RFID cards as the identification system for goods scanned over supermarket checkout scanners. Now RFID may well eliminate the ubiquitous bar code.
The inventor
"I feel good about it and gratified I could make a contribution," said Walton, a Los Gatos, Calif., resident who has a soft, halting voice, an easy laugh and a slow walk.
Walton, 83, made about $3 million from patenting RFID technology. But his last royalty-bearing RFID patent expired in the mid-1990s, meaning that he won't share in the potentially gigantic windfall that will be generated as Wal-Mart and the Defense Department begin to require their largest suppliers to put RFID tags on millions of warehoused goods.
"I'm disappointed it ran out after 17 years," Walton said of his patents. "It's not a bad law. I can't control it, and I'm not angry. I was never into stretching out the length of a patent because I was always more interested in inventing something new."
RFID had been around in various forms for years before Walton's invention of a radio-operated door lock. Earlier inventors received patents on animal control systems, a luggage handling system and a mail-sorting system. But Walton came up with a design that is popular today.
How the tags work
In his tags, a minute electrical current from a radio transceiver, or reader, wakes up a dormant card and gives it enough power to generate a response. A patent search shows his 1973 patent is referenced by 48 later inventions.
"For RFID, this is a pretty darn fundamental patent," said Bruce Sunstein, a patent attorney at Bromberg & amp; Sunstein in Boston.
Walton grew up in Maryland and New York as a ham radio enthusiast. He studied electrical engineering at Cornell University and went to work at IBM's research labs in 1960, where he learned the finer points of analog and digital computing. He left in 1970 to start his own company, Proximity Devices, in Sunnyvale, Calif. Over time, Walton has collected about 50 patents, five that yielded royalties.
Not everyone liked the RFID idea at first. Walton showed the technology to the board of directors of General Motors, which rejected it as too "Buck Rogers." He went a year without a salary as he shopped his invention around. Then he got lucky, licensing RFID to lock maker Schlage to make electronic locks that can open by waving a key card in front of a reader.
Walton still has a working mock-up of the door lock reader that he used to pitch Schlage. His first RFID card key was passive, meaning that it burned no battery power itself and was awakened when it came within six inches of a reader. The prototype has a 36-square-inch circuit board loaded with coiled wires and other components common in the 1970s. But there were no microchips that could house the entire RFID circuitry. Those came later with the progress of chip miniaturization.
Picking up speed
Once Schlage went into production in the late 1970s, the deal netted Walton a steady income each month so that he could continue inventing.
He also licensed the technology to other companies. In 1980, he received another patent for creating a digital version of RFID that could change data on the cards. Schlage's technology eventually ended up being owned by Westinghouse. There are now about four different RFID tags in use, two invented by Walton.
"After about 10 years, I began to make good money," he said.
But it was hard to win at the inventing game. Walton modified his invention to handle automated toll collection on roads and bridges. He put the tag in the license plate with the readers embedded in the road. Walton was edged out, however, by a competing RFID system that put tags in windshields and readers on the sides of toll booths.
Walton became rich enough from his first RFID patent to finance his own tinkering and to buy a big house on a 2-acre lot in the hills above Los Gatos.

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