Manufacturing optical elements

Abstract

A method of manufacturing an element using a replication tool, including the steps of providing a replication tool that defines the shape of the element; providing a substrate; pressing the tool against the substrate, with a replication material located between the tool and the substrate; confining the replication material to a predetermined area of the substrate, which predetermined area exceeds the desired area of the element on covering the substrate, in at least one direction along the surface of the substrate by less than a predetermined distance.; hardening (e.g. curing) the replication material to form the element.

1 . A method of manufacturing an element by means of a replication tool, comprising the steps of: 
 providing a replication tool that defines the shape of the element;    providing a substrate;    pressing the replication tool against the substrate, with a replication material in a liquid or viscous or plastically deformable state located between the replication tool and the substrate;    confining the replication material to a predetermined area of the substrate, which predetermined area exceeds a desired area of the element on the substrate, in at least one direction along a surface of the substrate by less than a predetermined distance;    hardening the replication material to form the element.    
   
   
       2 . The method of  claim 1 , wherein the replication tool comprises a plurality of sections each defining an element to be replicated, the method comprising the further step of: 
 applying a volume of replication material locally and individually, at a lateral position of each section, to at least one of the replication tool and the substrate prior to pressing the replication tool against the substrate.    
   
   
       3 . The method of  claim 2 , wherein the replication tool is chosen to comprise a plurality of cavities each defining the shape of one element or a group of elements, each cavity being limited, at least in one lateral direction, by a flat section, an inner edge being formed between the cavity and the flat section, the replication tool further comprising at least one overflow volume and an outer edge between the flat section and the overflow volume, and wherein said volume of replication material is larger than a volume of the cavity.  
   
   
       4 . The method of  claim 3 , wherein the flat section is asymmetrical with respect to a central axis of the element or group of elements.  
   
   
       5 . The method of  claim 2 , comprising the further steps of 
 confining flow of the replication material towards at least one side of the replication tool by a spacer that touches the substrate; and    enabling the flow of the replication material towards another side of the replication tool by an overflow channel.    
   
   
       6 . The method of  claim 1 , comprising the further step of 
 controlling flow of the replication material by at least one of capillary forces and of surface tension.    
   
   
       7 . The method of  claim 6 , comprising the further step of 
 applying a pre-determined volume of replication material, and    limiting flow of the replication material by at least one of capillary forces and surface tension acting at a discontinuity of the replication tool.    
   
   
       8 . The method of  claim 7 , wherein a cavity in the replication tool defines the shape of the element and includes a buffer volume along at least one side of the element, which buffer volume is separated from an element volume by an inner edge, wherein the pre-determined volume of replication material is smaller than a volume of the cavity, and wherein the method comprises the further step of 
 limiting the flow of the replication material into the buffer volume by at least one of capillary forces or surface tension acting at the inner edge.    
   
   
       9 . The method of  claim 2 , wherein the replication tool is chosen to comprise a plurality of cavities each defining the shape of one element or a group of elements, comprising the further step of 
 when pressing the replication tool against the substrate, an inclined spacer displaces the replication material towards one of said cavities.    
   
   
       10 . A replication tool for replicating an element from a replication material, the replication tool comprising a replication side, a plurality of cavities on the replication side, each defining the shape of one element or a group of elements, the replication tool further comprising at least one spacer portion, protruding, on the replication side, from the cavities, and further comprising means for confining the replication material to a predetermined area of the tool, when the tool is pressed against a substrate, which predetermined area exceeds a desired volume of the element in at least one direction along the surface of the substrate by less than a predetermined distance.  
   
   
       11 . The replication tool of  claim 10 , the cavity comprising an element volume and a further volume at a periphery of the element volume, boundaries of the further volume comprising discontinuities for selectively controlling flow of the replication material by means of at least one of capillary forces and of surface tension.  
   
   
       12 . The replication tool of  claim 11 , comprising 
 an edge dimensioned to stop the flow of the replication material at one side of the cavity; and    an overflow channel enabling the flow of the replication material towards another side of the cavity.    
   
   
       13 . The replication tool of  claim 10 , each cavity being limited, at least in one lateral direction, by a flat section serving as the spacer portion, an inner edge between the cavity and the flat section, an overflow volume and an outer edge between the flat section and the overflow volume.  
   
   
       14 . The replication tool of  claim 10 , further comprising a buffer volume at at least one side of an element volume defined by at least one of said cavities, the buffer volume and the element volume defining, at their common boundary, an inner edge for inhibiting the flow of the replication material into the buffer volume.  
   
   
       15 . The replication tool of  claim 14 , comprising further edges in the surface of the buffer volume for inhibiting the flow of the replication material into the buffer volume.  
   
   
       16 . The replication tool of  claim 10 , further comprising an inclined spacer at at least one side of at least one of said cavities.