Imaging apparatus and image sensor including the same
An image sensor includes a substrate, thin lenses disposed on a first surface of the substrate and configured to concentrate lights incident on the first surface, and light-sensing cells disposed on a second surface of the substrate, the second surface facing the first surface, and the light-sensing cells being configured to sense lights passing through the thin lenses, and generate electrical signals based on the sensed lights. A first thin lens and second thin lens of the thin lenses are configured to concentrate a first light and a second light, respectively, of the incident lights onto the light-sensing cells, the first light having a different wavelength than the second light.
1. An image sensor comprising:
a substrate;
a first thin lens configured to concentrate light of a first wavelength and comprising a plurality of first scatterers disposed on the substrate, a low refractive index material layer covering the plurality of first scatterers and a plurality of third scatterers disposed on the low refractive index material layer;
a second thin lens configured to concentrate light of a second wavelength, and comprising a plurality of second scatterers disposed on the substrate; and
a plurality of light-sensing cells configured to sense the light concentrated by the first thin lens and the second thin lens.
2. The image sensor of claim 1 , wherein the plurality of first scatterers and the plurality of third scatterers face each other to be misaligned with each other.
3. The image sensor of claim 2 , wherein at least two of the plurality of first scatterers or at least two of the plurality of second scatterers have different heights to each other.
4. The image sensor of claim 3 , wherein a height difference between the at least two of the plurality of first scatterers is equal to or less than 2λ 1 with respect to the first wavelength λ 1 .
5. The image sensor of claim 3 , wherein a height H of the plurality of first scatterers is in a range that λ 1 /2≤H≤3λ 1 with respect to the first wavelength λ 1 .
6. The image sensor of claim 3 , wherein a height difference between the at least two of the second scatterers is equal to or less than 2λ 2 with respect to the second wavelength λ 2 .
7. The image sensor of claim 3 , wherein a height H of the plurality of second scatterers is in a range that λ 2 /2≤H≤3λ 2 with respect to the second wavelength λ 2 .
8. The image sensor of claim 1 , wherein a separation distance in a height direction between a first scatterer and a third scatterer, which are adjacent to each other, among the plurality of first scatterers and the plurality of third scatterers is greater than λ 1 /2 with respect to the first wavelength λ 1 .
9. The image sensor of claim 1 , wherein a shape distribution of the plurality of first scatterers and a shape distribution of the plurality of third scatterers are determined to have different distributions of performance indexes by locations from each other.
10. The image sensor of claim 1 , wherein a shape distribution of the plurality of first scatterers and a shape distribution of the plurality of third scatterers are determined to compensate for non-uniformity of focusing performance by locations.
11. The image sensor of claim 1 , wherein the low refractive index material layer covers the plurality of second scatterers, and
the second thin lens further comprises a plurality of fourth scatterers disposed on the low refractive index material layer.
12. The image sensor of claim 11 , wherein the plurality of second scatterers and the plurality of fourth scatterers face each other to be misaligned with each other.
13. The image sensor of claim 12 , wherein at least two of the plurality of second scatterers or at least two of the plurality of fourth scatterers have different heights to each other.
14. The image sensor of claim 1 , wherein the first thin lens concentrates light of the first wavelength with a first focal length, and
the second thin lens concentrates light of the second wavelength with the first focal length.
15. The image sensor of claim 14 , further comprising a third thin lens configured to concentrate the light of the first wavelength with a second focal length that is different from the first focal length, the third thin lens comprising a plurality of fifth scatterers formed on the substrate.
16. The image sensor of claim 15 , wherein each of the first thin lens and the third thin lens comprises a plurality of regions in which a phase modulation in a predetermined range is repeated, and
the numbers of the plurality of regions in the first thin lens and the third thin lens are different from each other.
17. The image sensor of claim 15 , further comprising a fourth thin lens configured to concentrate the light of the second wavelength with the second focal length that is different from the first focal length, the fourth thin lens comprising a plurality of sixth scatterers formed on the substrate.
18. The image sensor of claim 17 , further comprising a low refractive index material layer covering the plurality of fifth scatterers and the plurality of sixth scatterers,
wherein the third thin lens further comprises a plurality of seventh scatterers disposed on the low refractive index material layer, and
the fourth thin lens further comprises a plurality of eighth scatterers disposed on the low refractive index material layer.
19. The image sensor of claim 18 , wherein the plurality of fifth scatterers and the plurality of seventh scatterers face each other to be misaligned with each other.
20. The image sensor of claim 18 , wherein the plurality of sixth scatterers and the plurality of eighth scatterers face each other to be misaligned with each other.