US Patent #2,612,994 was issued on October 7, 1952, to Joseph Woodland and Bernard Silver, for a round symbol with concentric circles or a linear label with lines and spaces which were readable by a special optical device. Silver proposed the linear barcode while a student at Drexel Institute in 1949; he and Woodland received their patent three years later. An idea for a scanning process for retail check out was proposed in 1932 by Wallace Flint in his masters thesis, but the equipment and technology to implement his idea were not practical and it was considered unworkable.
Now, sixty years after the first patent, the bar code is ubiquitous– used on a bag of carrots to your driver’s license to hospital id bracelets. There are several types of barcodes in use, including the linear barcode, the stacked bar code, and 2D barcodes. Linear barcodes use binary code represented as lines and spaces. We see linear barcodes everyday as the retail UPC symbol.
Libraries have implemented barcodes in a big way. For example, we use barcodes in books for inventory control. We use barcodes on library identification cards–in our case, your GWorld card–to make it easy for you to check out books and to authenticate use for off-campus access of our databases.