Method for balancing color response of imagers

Abstract

A micro-lens array with reduced or no empty space between individual micro-lenses and a method for forming same. The micro-lens array is formed by patterning a first set of micro-lens material in a checkerboard pattern on a substrate. The first set of micro-lens material is reflowed and cured into first micro-lenses impervious to subsequent reflows. Then, a second set of micro-lens material is patterned in spaces among the first micro-lenses, reflowed and cured into second micro-lenses. The reflows and cures can be conducted under different conditions, and the micro-lenses may be differently sized. The conditions of the reflows can be chosen to ensure that the focal lengths of micro-lenses are optimized for maximum sensor signal.

1 - 45 . (canceled)  
   
   
       46 . A method of forming a micro-lens array, comprising: 
 patterning a first set of micro-lens material onto a substrate;    reflowing the first set of micro-lens material under first reflow conditions;    curing the first set of micro-lens material to form a first set of micro-lenses including a plurality of first micro-lenses;    patterning a second set of micro-lens material onto the substrate;    reflowing the second set of micro-lens material; and    curing the second set of micro-lens material to form a second set of micro-lenses including a plurality of second micro-lenses;    wherein the second micro-lenses are each positioned in a space among the first micro-lenses.    
   
   
       47 . The method of  claim 46 , wherein said reflowing the second set of micro-lens material comprises reflowing the second set of micro-lens material under reflow conditions which are different than said first reflow conditions.  
   
   
       48 . The method of  claim 47 , wherein said first and second reflow conditions are chosen to create a focal length in said first micro-lenses substantially equal to a focal length in said second micro-lenses.  
   
   
       49 . The method of  claim 47 , wherein said first and second reflow conditions are chosen to create a focal length in said first micro-lenses corresponding to a first wavelength of light and to create a focal length in said second micro-lenses corresponding to a second wavelength of light.  
   
   
       50 . The method of  claim 46 , wherein said patterning a first set of micro-lens material comprises patterning the first set of micro-lens material into a first plurality of portions arranged in a checkerboard pattern, the checkerboard pattern including spaces between said portions.  
   
   
       51 . The method of  claim 50 , wherein said patterning a second set of micro-lens material comprises patterning the second set of micro-lens material into a second plurality of portions in a complementary checkerboard pattern filling in said spaces between the plurality of portions of the first set of micro-lens material.  
   
   
       52 . The method of  claim 51 , wherein said patterning a second set of micro-lens material comprises patterning the second set of micro-lens material overlapping said first micro-lenses.  
   
   
       53 . The method of  claim 51 , wherein said second plurality of portions comprise portions having a size no smaller than the size of the portions in the first plurality of patterns.  
   
   
       54 . The method of  claim 46 , further comprising: 
 patterning a third set of micro-lens material onto the substrate;    reflowing the third set of micro-lens material; and    curing the third set of micro-lens material to form a third set of micro-lenses including a plurality of third micro-lenses.    
   
   
       55 . The method of  claim 54 , wherein the patternings and reflow conditions of said first set, second set, and third set of micro-lens material create a micro-lens array having at least approximately no space between adjacent micro-lenses.