Nokia's ClearBlack Display technology has been announced in September 2010, but only now did they explained this technology fully. We knew that CBD adds a polarizing filter to a display (which can be either an LCD or an OLED) - but Nokia now tells us that the filter is placed between the touch layer and the actual display - which enables it to block incoming light and not harm the contrast or color quality. In the photo below, we can see a normal C6-01 phone with a CBD display (on the left) and the same phone without the CBD layer (on the right):

While the technology behind CBD displays is quite different to the one used in Samsung's Super AMOLED displays (which uses an on-cell touch layer) - the resulting image quality and behavior under sunlight is pretty similar in both display technologies.

CBD displays is used in five Nokia handsets (the E7 and the C6-01, the N9 and the Lumia 710 and Lumia 800) - out of which only the Lumia 710 uses an LCD - the rest has AMOLED displays.

Kyulux - Hyperfluoresence OLED emittersKyulux - Hyperfluoresence OLED emitters