Method of making a precision microlens mold and a microlens mold

Abstract

A method for making microlens molds and microlens array molds is described which utilizes a spinning half radius diamond cutting member operated in a plunge cut in a technique similar to milling to cut the optical surface into a diamond turnable material. The method can be used to make high sag lens molds with high accuracy. Microlens array molds can be made with a high degree of uniformity and a nearly 100% fill factor.

What is claimed is:  
     
         1 . Method of making a precision mold for a micro-sized optical article, comprising the steps of: 
 (a) providing a substrate;    (b) providing a forming element having a rotatable hardened cutting member, said hardened cutting member having a predetermined shape for forming a micro-sized mold cavity in said substrate;    (c) positioning said rotatable hardened cutting member into a milling relationship with said substrate; and,    (d) milling said substrate with said rotatable hardened cutting member to form a predetermined shaped micro-sized mold cavity for molding a micro-sized optical article.    
     
     
         2 . The method recited in  claim 1  wherein said micro-sized optical article is a microlens.  
     
     
         3 . The method recited in  claim 1  wherein said hardened cutting member comprises a generally contoured cutting face for forming a generally spherical shaped mold cavity in said substrate.  
     
     
         4 . The method recited in  claim 1  wherein said hardened cutting member comprises diamond.  
     
     
         5 . The method recited in  claim 4  wherein said substrate comprises materials selected from the group consisting of hardened nickel, nickel alloy, brass, copper, aluminum, and silicon.  
     
     
         6 . The method recited in  claim 4  wherein said substrate is hardened nickel plated substrate.  
     
     
         7 . The method recited in  claim 1  wherein said predetermined shaped micro-sized mold cavity is generally spherical and has a diameter of less than about 2 mm.  
     
     
         8 . The method recited in  claim 1  wherein said predetermined shaped micro-sized mold cavity is generally aspherical and has a diameter of less than about 2 mm.  
     
     
         9 . The method recited in  claim 1  wherein said predetermined shaped micro-sized mold cavity is generally anamorphic and has a diameter of less than about 2 mm.  
     
     
         10 . A microlens mold made with the method recited in  claim 7  having a sag of more than 30 microns.  
     
     
         11 . A microlens mold made with the method recited in  claim 8  having a sag of more than 30 microns.  
     
     
         12 . The microlens mold made with the method recited in  claim 9  having a sag of more than 30 microns.