Ok wanted to add something more, you see.

Red+ green+ blue = white.

So purple is created from Red and blue.

> the human eye is most sensitive to green, so when there is a transition the green is turned off leaving purple. (my theory anyways)
but it explains why amoled has a strange green tint. If RGB makes white then adding green will only make it green because light is a mixture of colours, adding more green as in the RG-BG configuration makes it green thus a green tint. So the purple is as a result of the technology/programming pentile layout.