Spectral filter, image sensor including the spectral filter, and electronic device including the spectral filter

An image sensor comprising:

• a pixel array comprising a plurality of pixels;
• and
• a spectral filter provided on the pixel array,
• wherein the spectral filter comprises:
• a plurality of first filter arrays, each of the plurality of first filter arrays comprising a plurality of band filters;
• and
• a plurality of second filter arrays respectively provided on the plurality of first filter arrays, each of the plurality of second filter arrays comprising a plurality of unit filters respectively corresponding to the plurality of band filters,
• wherein each of the plurality of unit filters comprises:
• a first reflecting plate;
• a second reflecting plate disposed above the first reflecting plate;
• and
• a single cavity between the first and second reflecting plates, the single cavity having a single central wavelength,
• wherein the single cavity comprises a cavity lower layer, a cavity upper layer, and a dielectric separation layer disposed between the cavity lower layer and the cavity upper layer,
• wherein the dielectric separation layer has a refractive index less than or equal to a maximum refractive index of the cavity lower layer of the single cavity and the cavity upper layer of the single cavity,
• wherein each of the plurality of band filters is configured to transmit light in a specific band,
• wherein the cavities of two or more of the plurality of unit filters are configured to have a same effective refractive index, and
• wherein a central wavelength of each unit filter of the plurality of unit filters corresponds to the single central wavelength of the single cavity included in each of the plurality of unit filters.

An electronic device comprising an image sensor,

• wherein the image sensor comprises:
• a pixel array comprising a plurality of pixels, and
• a spectral filter provided on the pixel array,
• wherein the spectral filter comprises:
• a plurality of first filter arrays, each of the plurality of first filter arrays comprising a plurality of band filters;
• and
• a plurality of second filter arrays respectively provided on the plurality of first filter arrays, each of the plurality of second filter arrays comprising a plurality of unit filters respectively corresponding to the plurality of band filters,
• wherein each of the plurality of unit filters comprises:
• a first reflecting plate;
• a second reflecting plate disposed above the first reflecting plate;
• and
• a single cavity between the first and second reflecting plates, the single cavity having a single central wavelength,
• wherein the single cavity comprises a cavity lower layer, a cavity upper layer, and a dielectric separation layer disposed between the cavity lower layer and the cavity upper layer,
• wherein the dielectric separation layer has a refractive index less than or equal to a maximum refractive index of the cavity lower layer of the single cavity and the cavity upper layer of the single cavity,
• wherein each of the plurality of band filters is configured to transmit light in a specific band, and
• wherein the cavities of two or more of the plurality of unit filters are configured to have a same effective refractive index, and
• wherein a central wavelength of each unit filter of the plurality of unit filters corresponds to the single central wavelength of the single cavity included in each of the plurality of unit filters.