Method and apparatus for labeling using diffraction grating-based encoded optical identification elements

Abstract

A method and apparatus for labeling an item using diffraction grating-based encoded optical identification elementsincludes an optical substratehaving at least one diffraction gratingdisposed therein. The gratinghas one or more colocated pitches Λ which represent a unique identification digital code that is detected when illuminated by incident light. The incident lightmay be directed transversely from the side of the substrate(or from an end) with a narrow band (single wavelength) or multiple wavelength source, and the code is represented by a spatial distribution of light or a wavelength spectrum, respectively, or a combination thereof. The elementcan provide a large number of unique codes, e.g., greater than 67 million codes, and can withstand harsh environments. The encoded elementmay be used to label any desired item, such as large or small objects, products, solids, powders, liquids, gases, plants, minerals, cells and/or animals, or any combination of or portion of one or more thereof. The label may be used for many different purposes, such as for sorting, tracking, identification, verification, authentication, anti-theft/anti-counterfeit, security/anti-terrorism, or for other purposes. In a manufacturing environment, the elementsmay be used to track inventory for production information or sales of goods/products.