Optical system

Abstract

An optical system and an image sensor including the same are provided. The optical system includes first, second, and third optical devices. At least one of the first, second, and third optical devices is a thin-lens including nanostructures.

What is claimed is: 
     
         1 . An optical system comprising:
 a first optical device configured to focus light, such that a focal point of light transmitted through the first optical device is dependent on an angle at which the light is incident on the first optical device;   a second optical device disposed such that light transmitted through 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 the second optical device on which the light is incident; and   a third optical device disposed such that the light transmitted through the second optical device is incident on 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 second optical device and the third optical device is a thin lens comprising a plurality of nanostructures and the thin lens is configured to correct at least one of a chromatic aberration and a geometric aberration that occurs in the remaining optical devices, and   wherein the thin lens is configured to adjust a phase delay distribution of the transmitted light according to at least one of shapes, cross sectional areas, heights, material compositions, and an interval of the nanostructures.   
     
     
         2 . The optical system of  claim 1 , wherein the thin lens is integrally formed with an adjacent optical device. 
     
     
         3 . The optical system of  claim 1 , wherein the nanostructures are provided on a surface of the thin lens on which the light is incident, on a surface of the thin lens on which the light exits, or on both surfaces of the thin lens. 
     
     
         4 . The optical system 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. 
     
     
         5 . The optical system of  claim 1 , wherein the optical system operates in an operating wavelength range of a band of wavelength. 
     
     
         6 . The optical system of  claim 1 , wherein the phase delay distribution comprises a transmission phase and amplitude distribution. 
     
     
         7 . The optical system of  claim 6 , wherein the transmission phase and amplitude distribution comprises a converging wave front or diverging wave front. 
     
     
         8 . The optical system of  claim 1 , wherein the thin lens comprises at least one material selected from a group consisting of SiO2, 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, TiO2, and SiN. 
     
     
         9 . The optical system 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. 
     
     
         10 . The optical system of  claim 1 , wherein the interval between the nanostructures is equal to or less than ¾ of a wavelength of the light. 
     
     
         11 . The optical system of  claim 1 , wherein the first optical device is a refractive optical lens, and the second optical device is the thin lens comprising the plurality of nanostructures. 
     
     
         12 . The optical system of  claim 11 , wherein the plurality of nanostructures of the second optical device are configured to offset a chromatic aberration of the second optical device and the third optical device. 
     
     
         13 . The optical system of  claim 12 , 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. 
     
     
         14 . The optical system of  claim 1 , wherein the first optical device is a thin lens.