Array cameras and array camera modules including spectral filters disposed outside of a constituent image sensor
View Patent ↗Systems and methods in accordance with embodiments of the invention implement array cameras and array camera modules that have spectral filters disposed outside of constituent image sensors. In one embodiment, an array camera module includes: a lens stack array including lens elements arranged to form a plurality of optical channels, each optical channel including a field-of-view that is shifted with respect to the fields-of-views of each other optical channel so that each shift includes a sub-pixel shifted view of the scene, a glass substrate located within an optical channel, and a spectral filter disposed within, or else proximate to, a glass substrate within the lens stack array; and an imager array including a plurality of focal planes, where each focal plane includes a plurality of rows of pixels that also form a plurality of columns of pixels, and where each focal plane does not include pixels from another focal plane.
1. An array camera module comprising:
lens elements arranged to form a plurality of optical channels, each optical channel comprising a separate aperture, and thereby being configured to image a distinct view of a scene;
a plurality of focal planes, where each focal plane comprises a plurality of rows of pixel stacks that also form a plurality of columns of pixel stacks, and where each focal plane does not include pixel stacks from another focal plane;
at least one cover glass that is disposed immediately adjacent to at least one focal plane and thereby covers all of the pixel stacks within the at least one focal plane; and
at least one spectral filter that is embedded within at least one cover glass;
wherein:
each optical channel is associated with a focal plane;
each pairing of an optical channel and a corresponding focal plane defines a camera;
the at least one cover glass is flat and uniformly thick;
the at least one spectral filter filters all the light that impinges on all of the pixel stacks of at least one focal plane; and
each pixel stack comprises a single microlens and a single photodetector, and each respective single microlens is configured to focus incident electromagnetic waves onto the corresponding single photodetector.
2. The array camera module of claim 1 , wherein each spectral filter within the array camera module is embedded within at least one cover glass.
3. The array camera module of claim 1 , wherein the cover glass is coated with an anti-reflective coating.
4. The array camera module of claim 1 , wherein the index of refraction of the spectral filter embedded within the cover glass is approximately similar to the index of refraction of the cover glass.
5. The array camera module of claim 1 , wherein the spectral filter is disposed between a first portion of the cover glass and a second portion of the cover glass wherein:
the first portion of the cover glass has a thickness greater than approximately 100 μm; and
the second portion of the cover glass has a thickness greater than approximately 100 μm.
6. The array camera module of claim 5 , wherein:
the first portion of the cover glass has a thickness greater than approximately 150 μm; and
the second portion of the cover glass has a thickness greater than approximately 150 μm.
7. The array camera module of claim 6 , wherein:
the first portion of the cover glass has a thickness greater than approximately 200 μm; and
the second portion of the cover glass has a thickness greater than approximately 200 μm.
8. The array camera module of claim 5 , wherein:
the spectral filter has a thickness of between approximately 0.1 μm and 1 μm.
9. The array camera module of claim 1 , wherein the spectral filter comprises blue glass and a dielectric infrared cut-off filter.
10. The array camera module of claim 9 , wherein the cover glass that includes the spectral filter that comprises blue glass and a dielectric infrared cut-off filter is sealed such so as to hinder the ability of ambient moisture to access the blue glass.
11. The array camera module of claim 10 , wherein the cover glass is sealed using resin.
12. The array camera module of claim 1 , wherein at least one pixel comprises a quantum film that itself comprises a plurality of quantum dots.
13. The array camera module of claim 1 , wherein at least one focal plane includes at least one spectral filter that is disposed proximate at least one pixel stack within the focal plane that filters the electromagnetic waves that are directed to the at least one photo detector of the focal plane.
14. The array camera module of claim 13 , wherein the at least one focal plane that includes at least one spectral filter includes a plurality of spectral filters that define a Bayer-filter pattern.
15. The array camera module of claim 14 , wherein at least one spectral filter that is embedded within a cover glass comprises blue glass and a dielectric infrared cut-off filter.
16. The array camera module of claim 1 , wherein each of the optical channels includes a field-of-view that is shifted with respect to the fields-of-views of each other optical channel so that each shift includes a sub-pixel shifted view of a targeted scene.
17. The array camera module of claim 1 , wherein the lens elements, the at least one cover glass, the at least one spectral filter, and the plurality of focal planes are embodied within a monolithic structure.
18. The array camera module of claim 1 , wherein the lens elements, the at least one cover glass, the at least one spectral filter, and the plurality of focal planes are embodied in a non-monolithic structure.