Image sensor including nanostructure color filter

An image sensor comprising:

• an optical sensor layer comprising a plurality of light-sensitive cells configured to sense to generate electrical signals;
• and
• a color filter array layer disposed on the optical sensor layer and comprising a plurality of color filters respectively facing the plurality of light-sensitive cells in a vertical direction of the image sensor, wherein
• at least one of the plurality of color filters comprises a plurality of nanostructures formed of a first material having a first refractive index, and a second material that surrounds the plurality of nanostructures and has a second refractive index less than the first refractive index,
• the plurality of nanostructures are disposed on the optical sensor layer at a first pitch in a horizontal direction of the image sensor,
• the first pitch is less than a central wavelength of a filtering color of the at least one of the plurality of color filters,
• the first material and the second material are alternately arranged two-dimensionally along two directions,
• the second material forms a structure having a strip shape, and the structure having the strip shape repeats one-dimensionally,
• lengthwise direction of the structure having the stripe shape differs in at least two of the plurality of color filters, and
• the lengthwise direction of the structure having the strip shape is a circumferential direction of a circle on a light-receiving surface which is defined by the plurality of the light-sensitive cells, and a center of the circle coincides with a center of the light-receiving surface.

An image sensor comprising:

• an optical sensor layer comprising a plurality of light-sensitive cells configured to sense light to generate electrical signals;
• and
• a color filter array layer disposed on the optical sensor layer and comprising a plurality of color filters respectively facing the plurality of light-sensitive cells in a vertical direction of the image sensor, wherein
• at least one of the plurality of color filters comprises a plurality of nanostructures formed of a first material having a first refractive index, and a second material that surrounds the plurality of nanostructures and has a second refractive index less than the first refractive index,
• the plurality of nanostructures are disposed on the optical sensor layer at a first pitch in a horizontal direction of the image sensor,
• the first pitch is less than a central wavelength of a filtering color of the at least one of the plurality of color filters,
• the first material and the second material are alternately arranged two-dimensionally along two directions,
• the second material forms a structure having a strip shape, and the structure having the strip shape repeats one-dimensionally,
• a lengthwise direction of the structure having the stripe shape differs in at least two of the plurality of color filters, and
• the lengthwise direction of the structure having the strip shape is a radial direction of a circle on a light-receiving surface which is defined by the plurality of light-sensitive cells, and a center of the circle coincides with a center of the light-receiving surface.

An image sensor comprising:

• an optical sensor layer comprising a plurality of light-sensitive cells configured to sense light to generate electrical signals;
• and
• a color filter array layer disposed on the optical sensor layer and comprising a plurality of color filters respectively facing the plurality of light-sensitive cells in a vertical direction of the image sensor, wherein
• at least one of the plurality of color filters comprises a plurality of nanostructures formed of a first material having a first refractive index, and a second material that surrounds the plurality of nanostructures and has a second refractive index less than the first refractive index,
• the plurality of nanostructures are disposed on the optical sensor layer at a first pitch in a horizontal direction of the image sensor,
• the first pitch is less than a central wavelength of a filtering color of the at least one of the plurality of color filters,
• a fill factor represents a ratio of a cross-section area of the first material to a cross-section area of one of the plurality of color filters, and
• the fill factor differs in at least two of the plurality of color filters.

An imaging apparatus comprising:

• a photographing lens unit configured to focus light reflected from an object and form an optical image;
• and
• an image sensor which is configured to convert the optical image formed by the photographing lens unit into an electrical signal and comprises:
• an optical sensor layer comprising a plurality of light-sensitive cells configured to sense light to generate electrical signals;
• and
• a color filter array layer disposed on the optical sensor layer and comprising a plurality of color filters respectively facing the plurality of light-sensitive cells in a vertical direction of the image sensor, wherein
• each of the plurality of color filters includes a plurality of nanostructure that has a first refractive index and is surrounded by a second material having a second refractive index higher than the first refractive index, wherein the plurality of nanostructures is disposed at a predetermined pitch in a horizontal direction of the image sensor, and
• the predetermined pitch is less than a central wavelength of a respective filtering color of the plurality of color filters, and
• shapes and an arrangement of the plurality of nanostructures and the second material of the at least one of the plurality of color filters are configured so that the at least one of the plurality of color filters is configured to focus incident light thereon on at least one of the plurality of light-sensitive cells.