Laser marking process on retro-reflective material for security labels

Abstract

A simplified method and apparatus for creating counterfeit-resistant labels is described. A laser is used to mark a retro-reflective material such that light only from specific directions are reflected back towards the source. During authentication of the labels, the label is tilted to verify that only light from the specific directions are reflected back towards the source.

What is claimed is:  
     
         1 . An identification apparatus comprising: 
 a retro-reflective surface; and    laser created markings on the retro-reflective surface.    
     
     
         2 . The identification apparatus wherein the retro-reflective surface is formed from a layer of spherical beads.  
     
     
         3 . The identification apparatus of    claim 2    wherein the laser damages a portion of each bead marked by said laser such that each bead marked by the laser scatters incident light received from a source of light when the source of light is positioned normal to said retro-reflective surface.  
     
     
         4 . The identification apparatus of    claim 3    wherein each bead marked by the laser reflects light from an off axis source back towards the off axis source.  
     
     
         5 . The identification apparatus of further comprising: 
 a watermark embedded in the identification apparatus.    
     
     
         6 . The identification apparatus of    claim 2    wherein the layer of spherical beads are formed from plastic.  
     
     
         7 . A method of fabricating identification labels comprising: 
 moving a retro-reflective surface under a laser; and    adjusting a laser beam to mark a pattern into the retro-reflective surface.    
     
     
         8 . The method of    claim 7    wherein said adjusting of the laser is accomplished using a galvanometer.  
     
     
         9 . The method of    claim 7    wherein the laser beam is pulsed to prevent damage to the retro-reflective surface.  
     
     
         10 . The method of    claim 7    wherein the laser is a NdYAG laser.  
     
     
         11 . The method of    claim 7    wherein the laser is a carbon dioxide laser.  
     
     
         12 . The method of    claim 7    further comprising the acts of: 
 verifying the validity of the pattern by aligning a light source to illuminate the pattern and placing a detector in proximity with the light source such that the detector, the light source and the mark form an approximate line.  
 
     
     
         13 . The method of    claim 12    wherein the detector is a human eye.  
     
     
         14 . An apparatus to identify a product comprising; 
 means for focusing and reflecting incident light towards a source of the incident light; and    means for marking the means for focusing and reflecting incident light to create a marked surface reflecting off axis incident light towards the source and for scattering incident light arriving approximately normal to the surface.    
     
     
         15 . The apparatus of    claim 14    wherein the means for marking is a laser.  
     
     
         16 . The apparatus of    claim 14    wherein the means for focusing and reflecting incident light is a retro-reflective surface.  
     
     
         17 . The apparatus of    claim 16    wherein the retro-reflective surface includes a layer of reflective beads.