BRAGG DIFFRACTING SECURITY MARKER

摘要

PROBLEM TO BE SOLVED: To provide a security device which can be applied to a paper base material or a plastic base material used for package of a retail article.

SOLUTION: A method of marking an article with a watermark that diffracts radiation according to a Bragg's law is disclosed. The method includes a step of applying a regular and periodic array of particles to the article in a configuration that marks the article. The watermark includes the regular and periodic array of particles fixed in a matrix. The watermark may change colors with a viewing angle, may disappear and reappear with another viewing angle or may diffract non-visible radiation that is detectable at a certain angle of detection.

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