RALEIGH, N.C. - N. Joseph Woodland, 91, the coinventor of the bar code that labels nearly every product in stores and has boosted productivity in nearly every sector of commerce worldwide, has died.

Mr. Woodland, who was born in Atlantic City, died Sunday in Edgewater, N.J., from the effects of Alzheimer's disease and complications of his advanced age, his daughter, Susan Woodland, said Thursday.

Mr. Woodland and Bernard Silver were students at Philadelphia's Drexel Institute of Technology - now Drexel University - when Silver overheard a grocery executive asking an engineering school dean to channel students into research on how product information could be captured at checkout, Susan Woodland said.

Having earned a mechanical engineering degree, Mr. Woodland dropped out of graduate school and stole away to his grandparents' home in Miami to focus on developing a code that could capture details about an item, Susan Woodland.

The only code Mr. Woodland knew was the Morse Code he had learned in the Boy Scouts, his daughter said. One day, he drew dots and dashes as he sat on the beach and absent-mindedly left his fingers in the sand where they traced a series of parallel lines. "It was a moment of inspiration. He said, 'instead of dots and dashes I can have thick and thin bars,' " Susan Woodland said.

Mr. Woodland and Silver submitted their patent in 1949 for a code patterned on concentric circles that looked like a bull's eye. The patent was issued in 1952.

Mr. Woodland joined IBM in 1951 hoping to develop the bar code, but the technology wasn't accepted for more than two decades until lasers made it possible to read the code readily, the technology company said. In the early 1970s, Mr. Woodland moved to Raleigh, N.C., to join a team at IBM's Research Triangle Park facility. The team developed a bar-code-reading laser scanner system in response to demands from grocers.

IBM promoted a rectangular bar code that led to a standard for universal product code technology. Worldwide, about five billion products a day are now scanned and tracked.

Mr. Woodland was among those honored at the White House in 1992 for their achievements in technology. Last year, he was inducted into the National Inventors Hall of Fame with Silver, posthumously.

Besides his daughter Susan, Mr. Woodland is survived by his wife, Jacqueline; another daughter, Betsy Karpenkopf; a brother; and a granddaughter.