Imaging apparatus and image sensor including the same

1. An imaging apparatus comprising:

a first optical device configured to focus light, such that a focal point of light transmitted through an image-side surface of the first optical device is dependent on an angle at which the light is incident on an object-side surface of the first optical device, wherein the object-side surface of the first optical device is opposite the image-side surface of the first optical device;

a second optical device disposed such that light transmitted through an image-side surface of the first optical device is incident on the second optical device, and configured such that a focal length of light transmitted through the second optical device is dependent on a position on an object-side surface of the second optical device on which the light is incident, wherein the object-side surface of the second optical device is opposite the image-side surface of the second optical device; and

a third optical device disposed such that light transmitted through an image-side surface of the second optical device is incident on an object-side surface of the third optical device, wherein the object-side surface of the third optical device is opposite the image-side surface of the third optical device, and configured such that light transmitted through the third optical device forms at least one focal point on an image plane,

wherein at least one of the first optical device, the second optical device, the third optical device is a thin lens comprising a plurality of nanostructures; and

wherein the second optical device is further configured such that light focused on a principal optical axis of the second optical device is focused by a first focal length and light focused on a position spaced away from the principal optical axis of the second optical device is focused by a second focal length, longer than the first focal length.

2. An imaging apparatus comprising:

a first optical device configured to focus light, such that a focal point of light transmitted through an image-side surface of the first optical device is dependent on an angle at which the light is incident on an object-side surface of the first optical device, wherein the object-side surface of the first optical device is opposite the image-side surface of the first optical device;

a second optical device disposed such that light transmitted through an image-side surface of the first optical device is incident on the second optical device, and configured such that a focal length of light transmitted through the second optical device is dependent on a position on an object-side surface of the second optical device on which the light is incident, wherein the object-side surface of the second optical device is opposite the image-side surface of the second optical device; and

a third optical device disposed such that light transmitted through an image-side surface of the second optical device is incident on an object-side surface of the third optical device, wherein the object-side surface of the third optical device is opposite the image-side surface of the third optical device, and configured such that light transmitted through the third optical device forms at least one focal point on an image plane,

wherein at least one of the first optical device, the second optical device, the third optical device is a thin lens comprising a plurality of nanostructures; and

wherein the third optical device is configured such that light focused on a principal optical axis of the third optical device is focused by a first focal length and light focused on a position spaced away from the principal optical axis of the third optical device is focused by a second focal length shorter than the first focal length.

3. The imaging apparatus of claim 1 , wherein the first optical device has positive refractive power, the second optical device has negative refractive power, and the third optical device has positive refractive power.

4. The imaging apparatus of claim 1 , wherein the third optical device refracts light transmitted therethrough to be incident on the image plane at an angle normal to the image plane.

5. The imaging apparatus of claim 1 , wherein the first optical device is a refractive optical lens, and each of the second optical device and the third optical device is the thin lens comprising a plurality of nanostructures.

6. The imaging apparatus of claim 5 , wherein the pluralities of nanostructures of the second optical device and nanostructures of the third optical device are configured to offset chromatic aberration of the two devices with each other.

7. The imaging apparatus of claim 6 , wherein the first optical device is configured to offset at least one of a geometric aberration and a chromatic aberration of at least one of the second optical device and the third optical device.

8. The imaging apparatus of claim 1 , wherein the first optical device is the thin-lens comprising the plurality of nanostructures, and each of the second optical device and the third optical devices is a refractive optical lens.

9. The imaging apparatus of claim 8 , wherein the plurality of nanostructures of the first optical device are configured to offset at least one of a chromatic aberration and a geometric aberration that occur in at least one of the second optical device and the third optical device.

10. The imaging apparatus of claim 8 , wherein the first optical device is disposed on a surface of the second optical device.

11. The imaging apparatus of claim 1 , wherein the thin-lens further comprises a substrate, and the plurality of nanostructures are disposed on a surface of the substrate.

12. The imaging apparatus of claim 11 , wherein each of the plurality of nanostructures has a refractive index greater than a refractive index of the substrate.

13. The imaging apparatus of claim 11 , wherein the substrate comprises at least one material selected from a group consisting of SiO 2 , plastic, and poly(methyl methacrylate) (PMMA), and each of the plurality of nanostructures comprises at least one material selected from a group consisting of crystalline silicon (c-Si), polycrystalline silicon (p-Si), amorphous silicon (a-Si), III-V compound semiconductors, SiC, TiO 2 , and SiN.

14. The imaging apparatus of claim 1 , wherein each of the plurality of nanostructures has at least one of a circular cylindrical shape, an elliptic cylindrical shape, a rectangular parallelepiped and a polygonal prism shape.

15. The imaging apparatus of claim 1 , wherein at least one of the first optical device, the second optical device, and the third optical device is configured such that light of only a predetermined wavelength range from among light incident on the first optical device forms a focal point on the image plane.

16. The imaging apparatus of claim 15 , further comprising an optical filter which blocks light having a wavelength outside the predetermined wavelength range.

17. An imaging system comprising:

at least one imaging apparatus comprising:

a first optical device configured to focus light such that a focal point of light transmitted through an image-side surface of the first optical device is dependent on an angle at which the light is incident on an object-side surface of the first optical device,

wherein the object-side surface of the first optical device is opposite the image-side surface of the first optical device;

a second optical device disposed such that light transmitted through an image-sides surface of the first optical device is incident on the second optical device, and configured such that a focal length of light transmitted through the second optical device is dependent on a position on an object-side surface of the second optical device on which the light is incident, wherein the object-side surface of the second optical device is opposite the image-side surface of the second optical device; and

a third optical device disposed such that light transmitted through an image-side surface of the second optical device is incident on an object-side surface of the third optical device, wherein the object-side surface of the third optical device is opposite the image-side surface of the third optical device, and configured such that light transmitted through the third optical device forms at least one focal point on an image plane; and

at least one light measurer corresponding, respectively, to each of the at least one imaging apparatus and configured, respectively, to measure light incident on the image plane of each of the at least one imaging apparatus,

wherein at least one of the first optical device, the second optical device, and the third optical device is a thin-lens comprising a plurality of nanostructures; and

wherein the second optical device is further configured such that light focused on a principal optical axis of the second optical device is focused by a first focal length and light focused on a position spaced away from the principal optical axis of the second optical device is focused by a second focal length, longer than the first focal length.

18. The imaging system of claim 17 , wherein the at least one imaging apparatus comprises a plurality of imaging apparatuses and the at least one light measurer comprises a plurality of light measurers,

wherein at least two of the plurality of imaging apparatuses are configured such that light of at least two different wavelength ranges forms focal points on the image plane.