Modified two-dimensional codes, and laser systems and methods for producing such codes

摘要

Each black square within a two-dimensional code can be represented by a distribution of spots. Each spot can be made small enough to be invisible to the human eye so that the two-dimensional code can be invisible on or within transparent or nontransparent materials. The spots can be spaced at a large distance to increase the signal-to-noise ratio for an optical code reader. A laser can be used to produce the spots.

主权项

1. A method for marking a substrate with a two-dimensional identification code represented by an array of designated and undesignated geometric areas, comprising:
generating laser pulses; and directing the laser pulses at the substrate to form a distribution of spots on or within the substrate, wherein the distribution of spots represents the two-dimensional code and comprises multiple groups of spots, including first and second groups that each include multiple spaced-apart spots, wherein each of the first and second groups of spots is representative of a designated geometric shape, such that the distribution of spots forms an array of multiple rows and columns of geometric areas, wherein some of the geometric areas include one group of spots and some of the geometric areas are devoid of spots such that the geometric areas that include one group of spots represent the designated geometric areas and such that the geometric areas that are devoid of spots represent the undesignated geometric areas.