OPTICAL ELEMENT, IMAGE SENSOR AND IMAGING DEVICE

1 . An optical element comprising:

a transparent layer for covering a pixel layer including a plurality of pixels each including a photoelectric conversion element, wherein the transparent layer includes a transparent substrate and an air layer, wherein the air layer is located between the pixel layer and the transparent substrate; and

a plurality of structures disposed in multiple layers including at least a first layer and a second layer, wherein structures in the first layer are disposed in the air layer, and structures in the second layer are disposed in the transparent layer.

2 . The optical element according to claim 1 ,

wherein each of the plurality of structures is a columnar structure which has a refractive index higher than a refractive index of the transparent layer, and gives an optical phase delay amount to light propagating in the structure,

at least parts of the structures disposed in each layer overlap each other in a plan view, and

each of the plurality of structures has a height capable of giving the optical phase delay amount of 2π or more to light propagating in each of the structures disposed in a stacking direction.

3 . The optical element according to claim 1 ,

wherein the plurality of structures are disposed in multiple layers according to an optical phase delay amount distribution for condensing the light of the corresponding color on the corresponding pixel.

4 . An imaging device comprising:

an imaging element including the optical element according to claim 1 , and a plurality of pixels covered with the transparent layer; and

a signal processing unit which generates a pixel signal on the basis of an electrical signal obtained from the imaging element.

5 - 8 . (canceled)

9 . An optical element comprising:

a transparent layer for covering a plurality of pixels each including a photoelectric conversion element; and

a plurality of structures disposed in a plane direction of the transparent layer, on a side opposite to the plurality of pixels with at least a part of the transparent layer interposed therebetween,

wherein heights of the plurality of structures belonging to at least one layer among multiple layers are longer than length represented by the right side of a following formula (3)

h

layer

≧

1

L

⁢

λ

r

n

1

-

n

0

.

(

3

)

10 . The optical element according to claim 9 ,

wherein the plurality of structures are disposed in multiple layers to guide light of a color corresponding to each of the plurality of pixels among incident light to a corresponding pixel.

11 . The optical element according to claim 9 ,

wherein each of the plurality of structures is a columnar structure which has a refractive index higher than a refractive index of the transparent layer, and gives an optical phase delay amount to light propagating in the structure,

at least parts of the structures disposed in each layer overlap each other in a plan view, and

each of the plurality of structures has a height capable of giving the optical phase delay amount of 2π or more to light propagating in each of the structures disposed in a stacking direction.

12 . The optical element according to claim 9 ,

wherein the plurality of structures are disposed in multiple layers according to an optical phase delay amount distribution for condensing the light of the corresponding color on the corresponding pixel.

13 . An imaging device comprising:

an imaging element including the optical element according to claim 9 , and a plurality of pixels covered with the transparent layer; and

a signal processing unit which generates a pixel signal on the basis of an electrical signal obtained from the imaging element.

14 . An optical element comprising:

a transparent layer for covering a plurality of pixels each including a photoelectric conversion element; and

a plurality of structures disposed in a plane direction of the transparent layer, on a side opposite to the plurality of pixels with at least a part of the transparent layer interposed therebetween,

wherein heights of the plurality of structures belonging to at least one layer among multiple layers are shorter than length represented by λr/(n1−n0).

15 . The optical element according to claim 14 ,

wherein the plurality of structures are disposed in multiple layers to guide light of a color corresponding to each of the plurality of pixels among incident light to a corresponding pixel.

16 . The optical element according to claim 14 ,

wherein each of the plurality of structures is a columnar structure which has a refractive index higher than a refractive index of the transparent layer, and gives an optical phase delay amount to light propagating in the structure,

at least parts of the structures disposed in each layer overlap each other in a plan view, and

each of the plurality of structures has a height capable of giving the optical phase delay amount of 2π or more to light propagating in each of the structures disposed in a stacking direction.

17 . The optical element according to claim 14 ,

wherein the plurality of structures are disposed in multiple layers according to an optical phase delay amount distribution for condensing the light of the corresponding color on the corresponding pixel.

18 . An imaging device comprising:

an imaging element including the optical element according to claim 14 , and a plurality of pixels covered with the transparent layer; and

a signal processing unit which generates a pixel signal on the basis of an electrical signal obtained from the imaging element.