Imaging systems for infrared and visible imaging with patterned infrared cutoff filters
View Patent ↗An image sensor may include a pixel array having visible and infrared imaging pixels for simultaneously detecting light in the visible and infrared spectral ranges. The pixel array may include an array of photodiodes, an array of filter elements formed over the photodiodes, and an array of microlenses formed over the array of filter elements. The filter elements may include infrared cutoff filter elements that block infrared light while passing visible light. The infrared cutoff filter elements may be formed from a patterned layer of infrared blocking material. Each visible imaging pixel includes a portion of the infrared blocking material and a color filter element. Each infrared imaging pixel is aligned with an opening in the infrared blocking material. The opening may be filled with an infrared pass filter element that passes infrared light while blocking visible light.
1. An image pixel array, comprising:
a plurality of photodiodes, wherein the image pixel array includes visible imaging pixels for detecting light in the visible spectrum and infrared imaging pixels for detecting light in the infrared spectrum;
an array of microlenses, wherein each microlens focuses light onto a respective one of the photodiodes;
a patterned layer of infrared light blocking material interposed between the array of microlenses and the plurality of photodiodes, wherein the infrared light blocking material transmits visible light and blocks infrared light, wherein the patterned layer of infrared light blocking material includes a plurality of openings, and wherein each opening is aligned with a respective one of the infrared imaging pixels; and
a plurality of infrared pass filter elements, wherein each infrared pass filter element is formed in a respective one of the openings in the infrared light blocking material, wherein each infrared pass filter element is completely surrounded by the patterned layer of infrared light blocking material, and wherein each infrared pass filter element blocks visible light and transmits infrared light to a respective photodiode associated with the respective one of the infrared imaging pixels.
2. The image pixel array defined in claim 1 wherein each infrared pass filter element comprises black polymer.
3. The image pixel array defined in claim 1 further comprising:
an array of color filter elements interposed between the array of microlenses and the plurality of photodiodes, wherein each color filter element in the array of color filter elements overlaps a respective portion of the infrared light blocking material.
4. The image pixel array defined in claim 3 wherein the patterned layer of infrared light blocking material is interposed between the array of color filter elements and the plurality of photodiodes.
5. The image pixel array defined in claim 3 wherein the patterned layer of infrared light blocking material is interposed between the array of microlenses and the array of color filter elements.
6. The image pixel array defined in claim 1 wherein the infrared light blocking material comprises photoimageable polymer that passes all wavelengths of visible light.
7. A system, comprising:
a central processing unit;
memory;
input-output circuitry; and
an imaging device having a pixel array, wherein the pixel array comprises:
a plurality of photodiodes, wherein the image pixel array includes visible imaging pixels for detecting light in the visible spectrum and infrared imaging pixels for detecting light in the infrared spectrum;
an array of microlenses, wherein each microlens focuses light onto a respective one of the photodiodes;
a patterned layer of infrared light blocking material interposed between the array of microlenses and the plurality of photodiodes, wherein the infrared light blocking material transmits visible light and blocks infrared light, wherein the patterned layer of infrared light blocking material includes a plurality of openings, and wherein each opening is aligned with a respective one of the infrared imaging pixels; and
a plurality of infrared pass filter elements, wherein each infrared pass filter element is formed in a respective one of the openings in the infrared light blocking material, wherein each infrared pass filter element is completely surrounded by the patterned layer of infrared light blocking material, and wherein each infrared pass filter element blocks visible light and transmits infrared light to a respective photodiode associated with the respective one of the infrared imaging pixels.
8. The system defined in claim 7 wherein each infrared pass filter element comprises black polymer.
9. The system defined in claim 7 further comprising:
an array of color filter elements interposed between the array of microlenses and the plurality of photodiodes, wherein each color filter element in the array of color filter elements overlaps a respective portion of the infrared light blocking material.
10. The system defined in claim 9 wherein the patterned layer of infrared light blocking material is interposed between the array of color filter elements and the plurality of photodiodes.
11. The system defined in claim 9 wherein the patterned layer of infrared light blocking material is interposed between the array of microlenses and the array of color filter elements.
12. The system defined in claim 7 wherein the infrared light blocking material comprises photoimageable polymer that passes all wavelengths of visible light.