Methods and apparatus for an image sensor

1. An image sensor, comprising:

a substrate, comprising a plurality of pixels;

an array of dielectric elements disposed on a surface of the substrate, wherein;

each dielectric element comprises a convex surface extending upwardly away from the surface of the substrate; and

each dielectric element corresponds to and is vertically aligned with one pixel;

an array of color filters, wherein:

each color filter is disposed on the convex surface of one dielectric element; and

each color filter comprises a convex surface positioned above the convex surface of the dielectric element; and

wherein:

the substrate, the array of dielectric elements, and the array of color filters form a vertical stack;

each of the substrate, the dielectric elements, and the color filters have a predetermined refractive index; and

the refractive indices of the vertical stack increase in value from the color filter to the substrate.

2. The image sensor according to claim 1 , wherein the substrate further comprises a plurality of isolation trenches disposed between adjacent pixels.

3. The image sensor according to claim 1 , further comprising a grid system disposed on the surface of the substrate and between adjacent dielectric elements.

4. The image sensor according to claim 3 , wherein:

the grid system is disposed between the color filters and the substrate; and

a portion of at least one color filter abuts the grid system.

5. The image sensor according to claim 3 , wherein:

the grid system is disposed between the dielectric elements and the substrate; and

adjacent dielectric elements overlap the grid system and abut each other.

6. The image sensor according to claim 3 , wherein:

the grid system comprises a composite grid structure arranged between adjacent color filters; and

a first end of the composite grid structure extends from the surface of the substrate to the convex surfaces of the adjacent color filters.

7. The image sensor according to claim 6 , wherein the first end of the composite grid structure comprises a tapered edge.

8. The image sensor according to claim 1 , wherein:

the convex surface of each color filter is substantially equal in shape to the convex surface of the underlying dielectric element; and

a distance between the convex surface of the color filter and the convex surface of the underlying dielectric element is substantially uniform.

9. An imaging system, comprising:

a substrate, comprising:

an array of pixels arranged in rows and columns; and

a plurality of isolation trenches arranged between adjacent pixels;

an array of dielectric elements disposed on a surface of the substrate; wherein:

each dielectric element is aligned vertically with one pixel of the array; and

each dielectric element comprises a convex surface extending from a first edge to a second edge and extending upwardly away from the surface of the substrate;

a grid system, wherein the grid system is disposed between adjacent dielectric elements and between the rows and columns of the array of pixels;

an array of color filters, each color filter disposed on the convex surface of one dielectric element; wherein:

each color filter comprises a convex surface extending from a first edge to a second edge and positioned above the convex surface of the dielectric element; and

the convex surface of the color filter is substantially equal in shape to the convex surface of the dielectric elements; and

wherein:

the substrate, the dielectric elements, and the color filters form a vertical stack;

each of the substrate, the dielectric elements, and the color filters have a predetermined refractive index; and

the refractive indices of the vertical stack increase in value from the color filter to the substrate.

10. The imaging system according to claim 9 , wherein:

the grid system is disposed between the color filters and the substrate; and

a portion of at least one color filter abuts the grid system.

11. The imaging system according to claim 9 , wherein:

the grid system is disposed between the dielectric elements and the substrate; and

adjacent dielectric elements overlap the grid system and abut each other.

12. The imaging system according to claim 9 , wherein the grid system comprises a composite grid structure arranged between adjacent color filters, and wherein a first end of the composite grid structure extends from the surface of the substrate to the convex surfaces of the adjacent color filters.

13. The imaging system according to claim 12 , wherein the first end of the composite grid structure comprises a tapered edge.

14. A method for forming an image sensor utilizing a substrate, comprising:

forming an array of dielectric elements on a surface of the substrate, wherein each dielectric element comprises a convex surface extending upwardly away from the surface of the substrate;

forming an array of color filters on the convex surface of the dielectric elements, wherein:

each color filter comprises a convex surface substantially equal in shape to the convex surface of the dielectric element; and

each color filter is vertically aligned with one dielectric element; and

wherein forming the array of color filters comprises:

forming a color filter layer on the convex surface of the dielectric elements; and

etching the color filter layer to form the convex surface of each color filter.

15. The method for forming an image sensor according to claim 14 , further comprising forming, in the substrate, a plurality of pixels and a plurality of isolation trenches between adjacent pixels.

16. The method for forming an image sensor according to claim 14 , further comprising forming a metal grid on the surface of the substrate and between adjacent dielectric elements.

17. The method for forming an image sensor according to claim 14 , further comprising forming a composite grid structure between adjacent color filters, wherein the composite grid structure comprises a metal layer and a dielectric layer.

18. The method for forming an image sensor according to claim 17 , wherein forming the composite grid structure further comprises forming the metal layer on the convex surface of the dielectric elements.

19. The method for forming an image sensor according to claim 14 , wherein forming the plurality of dielectric elements comprises:

forming a dielectric layer on the surface of the substrate;

etching the dielectric layer to form the convex surface of each dielectric element.