Multi-layer color filter for low color error and high SNR
Embodiments are described of a color filter array including a plurality of tiled minimal repeating units. Each minimal repeating unit includes an invisible-wavelength filter layer including a plurality of filters and a visible-wavelength filter layer positioned on the invisible-wavelength filter layer and having a plurality of filters such that each filter from the visible-wavelength layer is optically coupled to a corresponding filter in the invisible-wavelength layer.
1. A color filter array comprising:
a plurality of tiled minimal repeating units, each minimal repeating unit comprising:
an invisible-wavelength filter layer including a plurality of filters, the plurality of filters in the invisible-wavelength filter layer including at least three filters having a first invisible photoresponse and a filter having a second invisible photoresponse; and
a visible-wavelength filter layer positioned on the invisible-wavelength filter layer and having a plurality of filters such that each filter from the visible-wavelength layer is optically coupled to a corresponding filter in the invisible-wavelength layer, wherein the plurality of filters in the visible-wavelength filter layer includes a filter having a first visible photoresponse, a pair of filters having a second visible photoresponse, and a filter having a third visible photoresponse;
wherein the individual filter having the second invisible photoresponse is optically coupled to one of the pair individual filters with the second visible photoresponse, and
wherein the filters with the first and third visible photoresponses and the other filter of the pair of filters with the second visible photoresponse are optically coupled to filters with the first invisible photoresponse.
2. The color filter array of claim 1 wherein the first visible photoresponse is red, the second visible photoresponse is green, and the third visible photoresponse is blue.
3. The color filter array of claim 2 wherein the first invisible photoresponse is infrared-blocking and the second invisible photoresponse is infrared-passing.
4. The color filter array of claim 2 wherein the first, second, and third visible photoresponses are arranged in a Bayer pattern.
5. The color filter array of claim 1 wherein the first visible photoresponse is magenta, the second visible photoresponse is yellow, and the third visible photoresponse is cyan.
6. The color filter array of claim 5 wherein the first invisible photoresponse is infrared-blocking and the second invisible photoresponse is infrared-passing.
7. An image sensor comprising:
a pixel array including a plurality of individual pixels;
a color filter array positioned over and optically coupled to the pixel array, the color filter array comprising a plurality of tiled minimal repeating units, each minimal repeating unit comprising:
an invisible-wavelength filter layer including a plurality of filters, the plurality of filters in the invisible-wavelength filter layer including at least three filters having a first invisible photoresponse and a filter having a second invisible photoresponse; and
a visible-wavelength filter layer positioned on the invisible-wavelength filter layer and having a plurality of filters such that each filter from the visible-wavelength layer is optically coupled to a corresponding filter in the invisible-wavelength layer, wherein the plurality of filters in the visible-wavelength filter layer includes a filter having a first visible photoresponse, a pair of filters having a second visible photoresponse, and a filter having a third visible photoresponse;
wherein the individual filter having the second invisible photoresponse is optically coupled to one of the pair individual filters with the second visible photoresponse, and
wherein the filters with the first and third visible photoresponses and the other filter of the pair of filters with the second visible photoresponse are optically coupled to filters with the first invisible photoresponse.
8. The image sensor of claim 7 wherein the first visible photoresponse is red, the second visible photoresponse is green, and the third visible photoresponse is blue.
9. The image sensor of claim 8 wherein the first invisible photoresponse is infrared-blocking and the second invisible photoresponse is infrared-passing.
10. The image sensor of claim 8 wherein the first, second, and third visible photoresponses are arranged in a Bayer pattern.
11. The image sensor of claim 7 wherein the first visible photoresponse is magenta, the second visible photoresponse is yellow, and the third visible photoresponse is cyan.
12. The image sensor of claim 11 wherein the first invisible photoresponse is infrared-blocking and the second invisible photoresponse is infrared-passing.