Method and apparatus providing a microlens for an image sensor

An image sensor comprising:

• a pixel array comprising a plurality of pixels, each having a photosensor;
• a microlens array formed over the pixel array, the microlens array comprising a plurality of microlenses with a substantially flat upper surface, each microlens comprising a lens material unit comprising a plurality of separated blocks arranged in rows and columns separated by a plurality of trenches;
• and
• a fill material filling the trenches;
• wherein an index of refraction of the fill material and an index of refraction of the lens material unit of an associated microlens introduce an average refractive index reduction from a center to an edge of an associated microlens.

A camera system comprising:

• a processor;
• and
• an imager connected to the processor and comprising:
• a substrate having a plurality of pixels formed thereon, each pixel having a photosensor;
• and
• a microlens array formed above the pixels and comprising a plurality of microlenses, each microlens including a lens material unit, each lens material unit comprising a plurality of separated blocks arranged in rows and columns separated by a plurality of trenches, wherein the lens material unit has a substantially flat upper surface;
• wherein from a center to an edge of at least one of the microlenses a cross-sectional width of a trench is greater than a cross-sectional width of a previous trench;
• wherein from the center to the edge of the at least one of the microlenses a cross-sectional width of a block of the lens material unit is smaller than a cross-sectional width of a previous block of the lens material unit.

A method of forming an image sensor comprising:

• forming a pixel array comprising a plurality of pixels in a substrate, each pixel having a photosensor;
• forming a microlens array having a substantially flat upper surface and comprising a plurality of microlenses, each microlens having a lens material unit comprising a plurality of separated blocks arranged in rows and columns separated by a plurality of trenches, each microlens being positioned above at least one pixel of the pixel array;
• and
• filling the trenches with a fill material;
• wherein the cross-sectional widths of the trenches increase in the direction starting from a focal point of the photosensor towards an edge of an associated microlens, the focal point being aligned with a center of the associated microlens.