Barcode Knowledge
1. Origin and Development
The barcode concept dates back to the late 1940s. In 1949, Norman Joseph Woodland and Bernard Silver at Drexel University filed a patent for a bullseye-style barcode, laying the foundation of modern barcode technology.
On June 26, 1974, the first UPC-labeled product — a pack of Wrigley's gum — was scanned at a Marsh supermarket in Troy, Ohio, marking the beginning of commercial barcode use. Since then, barcodes spread rapidly across global retail.
From the 1980s, barcodes expanded into logistics, manufacturing, healthcare, and libraries. In 1994, Denso Wave invented QR Code, ushering in the 2D era. In the 21st century, barcodes have deeply integrated with mobile internet and IoT in payments, traceability, and marketing.
2. Encoding Principles
1D barcodes encode information via bars and spaces of varying widths. Each symbology defines a mapping of characters to bar/space patterns. For Code128, each character consists of 3 bars and 3 spaces spanning 11 modules, distinguished by widths.
2D barcodes encode information in a matrix. For QR Code, the structure includes finder patterns, alignment patterns, format information, version information, data area, and error correction area. Data is encoded, error-corrected, masked, and placed as modules.
3. Check Digit Mechanism
To ensure accuracy, many symbologies include check digits. The check digit is computed from the original data; scanners recompute and compare it, rejecting a read if mismatched.
For Code128, the check digit is computed by summing the start character and weighted data character values, taking modulo 103, and converting to the corresponding character. QR Code uses Reed-Solomon error correction, allowing correct decoding even with partial damage.
4. Common Standards
- EAN-13: 13-digit European Article Number for global retail
- UPC-A: 12-digit Universal Product Code, mainly North American retail
- ISBN: International Standard Book Number
- GS1-128: Code128-based logistics standard for supply chain
- QR Code: ISO/IEC 18004 2D standard
5. Scanning Principles
Scanners illuminate the barcode and use photoelectric sensors to receive reflected light. Different reflectivity between bars and spaces generates electrical signals that are decoded back to data. Laser, CCD, and imager scanners are the three main technologies.
2D imagers can read both 1D and 2D barcodes with stronger fault tolerance and environmental adaptability, becoming mainstream today.
6. Future Trends
With IoT, AI, and mobile internet, barcodes are evolving toward higher density, stronger error correction, and greater security. Digital watermark barcodes, color barcodes, and invisible barcodes are emerging in anti-counterfeiting, smart packaging, and AR interaction.
Integration with RFID and NFC is driving automatic identification toward more intelligent and efficient development.