Manufactured product with optically encoded particle tag and id method

Abstract

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.