The Barcode — The Lines on Every Product in Every Store

Norman Woodland and Bernard Silver's 1952 patent describes the first barcode system — a machine-readable code using lines of varying width that encodes product information, invented while Woodland was sketching in sand on a Miami beach.

What it covers

This patent describes a system for encoding and reading product classification data using printed patterns of lines, dots, or bulls-eye circles that vary in width and spacing. A light source illuminates the printed code; a photoelectric reader detects the varying light reflectance as dark lines absorb light and light spaces reflect it. The resulting electrical signal pattern — a series of wide and narrow pulses — corresponds to digits or letters that identify the product. The patent covers both the printed code itself and the optical scanner that reads it. Woodland and Silver's original concept used concentric circles (a bulls-eye) rather than lines, but the linear barcode proved more practical for manufacturing.

What it doesn't cover

• —The Universal Product Code (UPC) standard — the specific encoding system adopted in 1974 was developed separately by the Uniform Grocery Product Code Council
• —2D barcodes (QR codes, Data Matrix) — these encode data in two dimensions rather than one and were developed decades later
• —RFID tags — radio-frequency identification is a different technology that doesn't require line-of-sight optical reading
• —Laser scanning — the original patent used incandescent light; laser barcode scanners came in the 1970s

The clever bit

Bernard Silver overheard a Drexel University food chain executive asking a dean to find a system to automatically read product information at checkout. Silver told his graduate school friend Woodland, who became obsessed with the problem. Woodland was sitting on a Miami beach in 1948 when he absentmindedly drew lines in the sand with four fingers — then realized the varying widths of his lines were exactly what he needed. He extended the concept of Morse code (dots and dashes in time) into spatial patterns (wide and narrow lines in space). The patent was filed in 1949 and granted in 1952, but the technology sat dormant for 20 years until lasers and cheap computing made real-time scanning practical.

Why it matters

IBM bought Woodland and Silver's patent for $15,000 in 1962. Woodland became an IBM engineer and worked on the scanner systems that eventually commercialized the idea. He received no royalties from the billions of barcodes scanned daily. The patent had expired by the time the UPC standard launched in 1974. The barcode reduced supermarket checkout labor by 20–30%, enabled just-in-time inventory management, and made supply chain tracking possible at modern scale. It is one of the most economically impactful inventions of the 20th century — and one of the least celebrated.

Real-world examples

• 1.The first commercial barcode scan occurred on June 26, 1974, at a Marsh supermarket in Troy, Ohio — a pack of Wrigley's Juicy Fruit gum, now on display at the Smithsonian
• 2.Modern retail couldn't function without barcodes: a typical Walmart store scans over 1 million items per day; the average grocery store carries 30,000 SKUs all identified by UPC barcodes
• 3.Healthcare adopted barcodes to track medications and patients — barcode scanning before drug administration is estimated to prevent millions of medication errors annually

Glossary