OLEDs are emissive devices so their spectra is just the sum of the individual Red, Green and Blue OLED spectra, modified slightly by the touchscreen layer and anti-reflection absorption layer through which their light must pass.
The Nexus One display is distinctive and unusual in several respects: it is an Organic LED display, which is an emissive display technology, whereas most mobile devices have an LCD display, which uses a static backlight behind the panel.