Tetraform microlenses and method of forming the same

Abstract

A lens is formed to support and tilt at least one microlens formed on the lens. The degree and direction of slope of the microlens can be controlled based on desired focal characteristics to direct light to or from a pixel of a pixel array.

1 - 30 . (canceled) 
     
     
         31 . A microlens structure comprising:
 a first lens supported by a portion of a pixel array, an upper surface of the lens having a slope with respect to an upper surface of the portion; and   at least one microlens supported by the first lens, wherein each microlens supported by the first lens is tilted by the upper surface of the first lens.   
     
     
         32 . A microlens structure according to  claim 31 , wherein each microlens is tilted at an angle, and further wherein the tilt angles of the microlenses are equal. 
     
     
         33 . A microlens structure according to  claim 31 , wherein each microlens is tilted at an angle of less than 10°. 
     
     
         34 . A microlens structure according to  claim 31 , wherein the first lens comprises a photoresist material. 
     
     
         35 . A microlens structure according to  claim 31 , said first lens and said at least one microlens comprise the same material. 
     
     
         36 . A microlens structure according to  claim 31 , wherein said at least one microlens is supported directly on the lens. 
     
     
         37 . A microlens structure according to  claim 31 , wherein each microlens is associated with a respective photosensitive device formed in the pixel array. 
     
     
         38 . A microlens structure according to  claim 37 , wherein the lens is supported by a color filter. 
     
     
         39 . A microlens structure according to  claim 38 , wherein exactly four microlenses are supported by the first lens. 
     
     
         40 . A microlens structure according to  claim 39 , wherein the color filter is a Bayer pattern and each microlens is associated with a color from a Bayer pattern. 
     
     
         41 . A microlens structure according to  claim 38 , wherein each microlens is associated with one color of the color filter. 
     
     
         42 . A microlens array comprising:
 a plurality of lenses formed over a photosensitive pixel array, wherein each lens comprises:
 a sloped upper surface; 
 a lower surface; 
 a height from an apex of the sloped upper surface to the lower surface; and 
 a horizontal distance, wherein the slope of the upper surface is defined by an angle formed by the tangent of the height to the horizontal distance. 
   at least one microlens located on each lens, wherein each microlens is tilted at said angle.   
     
     
         43 . A microlens array according to  claim 42 , wherein the angle is less than about 10 degrees. 
     
     
         44 . A microlens array according to  claim 42 , wherein each lens comprises a photoresist material. 
     
     
         45 . A microlens array according to  claim 42 , wherein each microlens comprises a photo resist material. 
     
     
         46 . A microlens array according to  claim 42 , wherein at least two of said plurality of microlenses are positioned over a common photosensitive device for directing incident light to the common photosensitive device. 
     
     
         47 . A microlens array according to  claim 42 , wherein each of said plurality of microlenses are positioned over a respective photosensitive device for directing incident light to the respective photosensitive device. 
     
     
         48 . An imager structure comprising:
 at least one pixel formed in a substrate;   at least one lens formed over the at least one pixel, the at least one lens having an upper surface sloped with respect to the pixel; and   at least one microlens associated with and supported by an associated lens, each microlens being positioned to pass incident light to an associated pixel through said associated lens and tilted by the upper surface of the associated lens.   
     
     
         49 . An imager structure as in  claim 48 , wherein each lens has similar shape and slopes in substantially the same direction. 
     
     
         50 . An imager structure as in  claim 48 , wherein at least one of said lens is upwardly convex in shape and slopes downward and away from a center of the lens, where the slope is substantially symmetric in each direction. 
     
     
         51 . An imager structure as in  claim 48 , wherein each lens and microlens have a circular shape. 
     
     
         52 . An imager structure as in  claim 48 , wherein each lens and microlens have a square shape. 
     
     
         53 . The imager structure as in  claim 48 , wherein each pixel comprises a photosensitive imaging device. 
     
     
         54 . An imager processing system as in  claim 48 , wherein each lens comprises:
 a horizontal distance;   a height; and   an angle defined by the tangent of the height to the horizontal distance, wherein each microlens of each group of microlenses is tilted at said angle.   
     
     
         55 . An imager processing system as in  claim 54 , wherein said angle is less than about 10 degrees. 
     
     
         56 . An image processing system comprising:
 a processor; and   an imager structure coupled to the processor, said imager structure comprising:
 a photosensitive pixel array; 
 a plurality of lenses formed over the plurality of pixels, each lens being associated with a plurality of pixels and having an upper surface sloped with respect to the plurality of pixels; and 
 a plurality of groups of microlenses, each group of microlenses being associated with and being respectively supported by an associated lens, each microlens supported by said associated lens being tilted by the upper surface of its associated lens. 
   
     
     
         57 . An image processing system of  claim 56 , wherein each lens has similar shape and slopes in substantially the same direction. 
     
     
         58 . An imager processing system as in  claim 56 , wherein at least one of said lens is upwardly convex in shape and slopes downward and away from a center of the lens, where the slope is substantially symmetric in each direction. 
     
     
         59 . An imager processing system as in  claim 56 , wherein each lens comprises:
 a horizontal distance;   a height; and   an angle defined by the tangent of the height to the horizontal distance, wherein each microlens of each group of microlenses is tilted at said angle.   
     
     
         60 . An imager processing system as in  claim 59 , wherein said angle is less than about 10 degrees.