Barcodes started in the late 1940s. The first barcode system was invented in 1948 by Norman Joseph Woodland and Bernard Silver, who created a "bull's-eye" style barcode. They filed a patent for their invention in 1949, which was granted in 1952. Early versions were impractical due to limitations in technology at the time. The first commercial use of barcodes began in the 1960s, with significant development in 1969 when David Collins invented a laser light source capable of reading barcodes. The Universal Product Code (UPC) standard, which is still widely used, was created in the early 1970s. The first product scanned with a UPC barcode at checkout was a pack of chewing gum in 1974. The first successful barcode system in retail supermarkets was implemented in 1972.
