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US 2007/0165903 A1Published application
Bragg diffracting security markers
AssigneePPG Industries Ohio, Inc.
InventorsCalum Munro, Mark Merritt, Sean Purdy
Life of this patent
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Abstract
A method of marking an article with a watermark that diffracts radiation according to Bragg's law is disclosed. The watermark includes a periodic array of particles fixed in a matrix. The watermark may change colors with viewing angle, disappear and reappear with viewing angle or may diffract non-visible radiation that is detectable at certain angles of detection.
Claims28
A method of marking an article with a radiation watermark comprising:
- applying an ordered periodic array of particles to an article in a configuration that marks the article, wherein the array diffracts radiation at a detectable wavelength.
A method of making an article exhibiting images comprising:
- applying a periodic array of particles onto the article in a configuration of an image;
- coating the array of particles with a matrix composition;
- and
- fixing the coated array of particles such that the image is detectable upon diffraction of radiation by the fixed array.
1 more element
A method of making an article exhibiting an image comprising:
- applying at least one matrix composition to the article in a configuration of an image;
- forming a periodic array of particles;
- embedding the array of particles within the matrix composition to coat the particles;
- and
- fixing the coated array of particles such that the image is detectable upon diffraction of radiation by the fixed array.
2 more elements
Dependencies are inferred from the claim text.