MANUFACTURED PRODUCT WITH OPTICALLY ENCODED PARTICLE TAG AND ID METHOD
The invention concerns an article of manufacture that is a manufactured product marked with a microparticle and a method of marking manufactured produces. The microparticle tag includes a predetermined code embedded in its physical structure by refractive index changes between different regions of the particle. The particle has a diameter of a few hundred microns or less and has a plurality of layers.
1 . An article of manufacture, comprising:
a manufactured product marked with a microparticle, wherein
the microparticle is incorporated into the manufactured product; and
the microparticle has a diameter of a few hundred microns or less and comprises
a first porous layer having a predetermined first porosity and thickness; and
a plurality of n additional porous layers having predetermined thicknesses and porosities, at least one of which has a predetermined porosity differing from said first porosity; wherein
said predetermined porosities and thicknesses of said first porous layer and said n additional porous layers are configured to produce an interference pattern in the reflectivity spectrum having a distinct series of peaks such that the interference pattern forms an optical signature having a particular predetermined code determined by the porosities and thicknesses of said first porous layer and said n additional porous layers.
2 . The article of claim 1 , wherein the manufactured product comprises a powder.
3 . The article of claim 1 , wherein the manufactured product comprises a paste.
4 . The article of claim 1 , wherein the manufactured product comprises a liquid.
5 . The article of claim 1 , wherein the manufactured product comprises a biological product.
6 . The article of claim 1 , wherein the manufactured product comprises a chemical product.
7 . The article of claim 1 , wherein said first porous layer and said n additional porous layers are formed from a semiconductor.
8 . The article of claim 7 , wherein said semiconductor comprises silicon.
9 . The article of claim 1 , wherein said first porous layer and said n additional porous layers are formed from an insulator.
10 . The article of claim 1 , wherein the microparticle has a diameter in the range from a few hundred nanometers to a few hundred microns.
11 . An article of manufacture, comprising a manufactured product marked with a microparticle, wherein the microparticle is incorporated into the manufactured product and the microparticle comprises an encoded micron-sized porous particle having a particular predetermined code embedded in its physical porous structure by refractive index changes between different porous regions of the particle, wherein the physical porous structure has a plurality of layers some of which have separate predetermined mismatched optical thicknesses and the microparticle has a diameter of a few hundred microns or less and is freestanding separated from any substrate other than the manufactured product itself.
12 . The article of claim 11 , wherein the porosity varies periodically.
13 . The article of claim 12 , wherein the particle comprises sets of porosities each varying to produce a code detectable in the reflectivity spectrum.
14 . The article of claim 11 , wherein the manufactured product comprises a powder.
15 . The article of claim 11 , wherein the manufactured product comprises a paste.
16 . The article of claim 11 , wherein the manufactured product comprises a liquid.
17 . The article of claim 11 , wherein the manufactured product comprises a biological product.
18 . The article of claim 11 , wherein the manufactured product comprises a chemical product.
19 . A method of marking a manufactured product, the method comprising incorporated an encoded microparticle in the manufactured product during manufacture, wherein the encoded microparticle comprises an encoded micron-sized porous particle having a particular predetermined code embedded in its physical porous structure by refractive index changes between different porous regions of the particle, wherein the physical porous structure has a plurality of layers some of which have separate predetermined mismatched optical thicknesses and the microparticle has a diameter of a few hundred microns or less and is freestanding separated from any substrate other than the manufactured product itself.