Kudos to one of our forums posters, 'imagewest' for spotting US Patent 7,138,663, assigned to Nikon Corporation of Japan. This patent describes a new type of image sensor which uses three small dichroic mirrors below an opening to direct red, green and blue light to separate photodiodes. This design would provide full color detail at each photo sensing location, a bit like Foveon's X3 sensor (although this design is quite different). A single 'pixel' of light passes first through an element which reflects blue light to the blue photodiode but allows red and green light to pass, the next element reflects green light to the green photodiode but allows red light to pass and the final element reflects red light to the red photodiode but absorbs infrared. Of course this design has all of the advantages we have seen from full-color sensors including, the primary disadvantages must be the complexity of the design and the poor 'fill factor' (which is mitigated somewhat by the use of microlenses). This patent was filed in 2003 so we will have to wait and see if it ever comes to fruition.