« on: October 08, 2014, 11:45:48 PM »
Thanks! That's gonna be some good readin'!
Here is one of the layered sensor patents from a few years ago (2011):
This one seems to apply the nanocoating concept to the red layer. Nanocoating uses nanoscopic scale spikes of differing sizes on a reflective surface to produce a non-abrupt transition layer. Reflections occur at abrupt transistions in refractive index, so by creating a non-abrupt transition layer, you can nearly eliminate reflections entirely. This is different from standard multicoating, which still allows reflections to occur, it just cancels them out via wave interference.
Here is another patent from 2012:
This is another sensitivity increasing patent. This apparently uses dielectric antireflective layers underneath the preceeding layer to reduce ghosting reflections. Not sure if this is intended to be used in conjunction with the nanocoating of the red layer or not...it seems to explicitly call out the blue and green layers (which are higher up than the red layer).
Canon also has their more recent patent for the five-layer sensor with UV and IR layers:
This patent is interesting, because it seems to depict a multi-layered BSI design, at least based on the diagram of the sensor (all the transistors are on the back side...that alone would be HUGE for layered sensor sensitivity...if you look at the ChipWorks electron micrographs of current Foveon designs, the transistors take up a huge amount of die space, as Foveon is still an FSI design...which is probably the biggest reason that sensor suffers so in low light.)
It was discovered some time ago that infrared light diffuses and reflects back subcutaneously in human skin. It can be used to greatly reduce the appearance of skin blemishes (I found a page a while back that shows that most skin features effectively disappear when you shoot full infrared). I'm not sure what UV light does for skin...apparently Canon found something useful with UV light.
Anyway, wtlloyd, there's some reference material. That's what Canon's got for multi-layered sensors.