Image sensor having integrated infrared-filtering optical device and related method
View Patent ↗An image sensing device is disclosed having a die formed with an array of photosensing sites and a structure of optical material having infrared absorbing characteristics formed over the photosensing sites. An embodiment is disclosed in which the structure of optical material having infrared absorbing characteristics is formed as an array of microlenses for directing visible image light onto the photosensing sites and at the same time filtering out infrared wavelengths that interfere with image capture. Alternatively, the structure may be designed to filter out other ranges of wavelengths outside of the visible spectrum.
1. An imaging device, comprising:
a substrate having photosensing elements;
a light-transmissive optical structure of microlenses on the substrate to direct light onto the photosensing elements;
wherein each microlens is a hemispherical or cylindrical shaped lens element and a mixture of polymer resin and a material that absorbs infrared energy from the light, and
the mixture forming each microlens is disposed as a single layer directly on and in contact with the substrate having the photosensing elements.
2. The imaging device of claim 1 wherein the optical structure of microlenses comprises an array.
3. The imaging device of claim 1 wherein the optical structure of microlenses comprises a plastic material formed into an array.
4. The imaging device of claim 3 wherein the plastic material comprises a dye that absorbs infrared energy.
5. The imaging device of claim 1 wherein the optical structure of microlenses comprises a plastic resin.
6. The imaging device of claim 5 wherein the optical structure of microlenses comprises a layer of plastic resin formed on the substrate into an array.
7. The imaging device of claim 1 wherein the photosensing elements include CMOS devices.
8. The imaging device of claim 1 wherein the optical structure of microlenses comprises a plastic substance formed on the substrate to direct light energy onto the photosensing elements, and
the plastic substance has a dye that selectively absorbs infrared energy.
9. An imaging device comprising:
a substrate including integrated electrical elements;
an array of lenses on the substrate;
a shell structure surrounding the array of lenses and having a top opening;
a light-transmissive cover attached to the top opening of the shell structure; and
inside each lens is a substance that is substantially transmissive of visible light and substantially absorbent of selected wavelengths of light outside the visible spectrum;
wherein the array of lenses have hemispherical or cylindrical shaped lens elements and is formed from a mixture of a polymer and a dye for absorbing the selected wavelengths of light outside the visible spectrum, and
the mixture forming the array of lenses is disposed as a single layer directly on and in contact with the substrate.
10. The imaging device of claim 9 wherein the cover comprises glass.
11. The imaging device of claim 9 wherein the array of lenses comprises a plastic resin mixed with a dye that absorbs energy in the infrared band.
12. The imaging device of claim 9 , further comprising a field lens mounted in spaced relation to the cover for directing image light onto the array of lenses.
13. The imaging device of claim 12 wherein the field lens comprises glass.
14. The imaging device of claim 9 wherein the electrical elements include CMOS devices.
15. The imaging device of claim 9 , further comprising an adhesive sealant attaching the cover to the shell structure to protect the array of lenses and substrate.
16. The imaging device of claim 9 wherein the array of lenses comprises microlenses formed on the substrate so as to focus light energy onto certain of the electrical elements.
17. The imaging device of claim 9 , further comprising color filters operable to cause the electrical elements to capture color content of an image.