An idea to improvement of Foveon sensors

Started May 3, 2013 | Discussions thread
detectorman Regular Member • Posts: 148
Re: An idea to improvement of Foveon sensors

The camera likely has an IR filter so that no IR gets to the red layer -- the red channel is not getting extra noise from IR. The amount of dark current in the red junction will be the highest because that layer has the largest volume of silicon material to absorb the longer wavelengths -- silicon absorbs strongest in the blue, less strong in green, and again less in the red. It is even weaker in the IR. It is this very feature that allows the Foveon sensor to work -- to separate the colors. The silicon material generates dark current in proportion to the volume of the material that the junction can collect electrons (or holes) from -- the electrons or holes diffuse to the junction, along with the electrons or holes that are generated by the light absorbed in that volume of material.

You should be able to check this -- the dark current should go down by a factor of 2 for every 8 degrees C that the camera temperature is reduced. Therefore, there will be less noise when it's colder outside, assuming the camera has had time to cool down of course. If you needed extra low noise you could perhaps store the camera in your refrigerator for a while and then use it before it warms up. Be cautious, that can lead to water condensation if the atmosphere is humid! Who knows whether the camera electronics would tolerate this? Batteries have less capacity when they're cold, but they will still work.

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