Process for producing an article with a microstructure

Abstract

A process for producing an article with a microstructure includes the steps of forming a primary relief structure on a surface of a substrate, applying a photo resist on the substrate, exposing part of the photo resist using a photo mask so as to form a microstructure pattern, developing the microstructure pattern in the exposed photo resist, thereby allowing access to a part of the primary relief structure from the photo resist, and thereby forming a patterned surface with a microstructure relief that is bounded by the exposed part of the primary relief structure and by remainder of the photo resist on the substrate, and forming a metal layer on the patterned surface to form the article having the microstructure with a profile corresponding to the microstructure relief on the patterned surface.

We claim:  
     
         1 . A process for producing an article with a microstructure, comprising the steps of: 
 a) forming a primary relief structure on a surface of a substrate;    b) applying a photo resist on the substrate;    c) exposing part of the photo resist using a photo mask so as to form a microstructure pattern; and    d) developing the microstructure pattern in the exposed photo resist, thereby allowing access to a part of the primary relief structure from the photo resist, and thereby forming a patterned surface with a microstructure relief that is bounded by the exposed part of the primary relief structure and by remainder of the photo resist on the substrate.    
     
     
         2 . The process of  claim 1 , wherein the substrate is made of a material selected from a group consisting of metal, glass, ceramic and plastic.  
     
     
         3 . The process of  claim 1 , wherein the primary relief structure includes a parallel set of first linear structures.  
     
     
         4 . The process of  claim 3 , wherein the primary relief structure further includes a parallel set of second linear structures that intersect said set of first linear structures.  
     
     
         5 . The process of  claim 1 , wherein the primary relief structure includes a set of concentric circular structures.  
     
     
         6 . The process of  claim 1 , wherein the primary relief structure includes a set of curved structures.  
     
     
         7 . The process of  claim 1 , wherein the primary relief structure includes at least one of a set of linear structures and a set of curved structures.  
     
     
         8 . The process of  claim 1 , wherein, in step (a), the primary relief structure is formed by diamond cutting.  
     
     
         9 . The process of  claim 1 , wherein the primary relief structure is recessed relative to the surface of the substrate.  
     
     
         10 . The process of  claim 9 , wherein, in step (b), the photo resist is applied on the substrate to fill up the primary relief structure.  
     
     
         11 . The process of  claim 10 , wherein, in step (b), the photo resist is applied on the substrate such that a surface of the photo resist is flush with the surface of the substrate.  
     
     
         12 . The process of  claim 1 , wherein the primary relief structure projects from the surface of the substrate.  
     
     
         13 . The process of  claim 1 , further comprising the step of: 
 e) forming a metal layer on the patterned surface to form the article having the microstructure with a profile corresponding to the microstructure relief on the patterned surface.    
     
     
         14 . The process of  claim 13 , further comprising the step of: 
 (f) forming a metal product on the metal layer such that the metal product has a microstructure with a profile that is the inverse of the microstructure on the article.    
     
     
         15 . The process of  claim 14 , wherein, in step (f), the metal product is formed by electroforming.  
     
     
         16 . The process of  claim 14 , wherein, in step (f), the metal product is formed by non-electric plating.  
     
     
         17 . The process of  claim 14 , wherein the metal product is a stamper or mold that is used to produce a product via metal casting.  
     
     
         18 . The process of  claim 14 , wherein the metal product is a stamper or mold that is used to produce a product via plastic molding.  
     
     
         19 . An optical reflective plate fabricated in accordance with the process defined in  claim 14 .  
     
     
         20 . An optical diffusing plate fabricated in accordance with the process defined in  claim 14 .  
     
     
         21 . A stamper fabricated in accordance with the process defined in  claim 14 .  
     
     
         22 . A light transmitting plate produced by using a stamper fabricated in accordance with the process defined in  claim 18 .  
     
     
         23 . A backlighting plate produced by using a stamper fabricated in accordance with the process defined in  claim 18 .  
     
     
         24 . A frontlighting plate produced by using a stamper fabricated in accordance with the process defined in  claim 18.