ClearBlack display uses a sequence of polarising layers to eliminate reflections.

You have probably tried polarising sunglasses before now and so have a rough idea of how that works. If you look at a window or the surface of some water using polarising glasses, then they become more transparent – which is why they’re especially good for fishermen. The polariser cuts out reflected light.

Polariser layers used in display solutions are bit more sophisticated than in sunglasses. Light rays actually gets “processed” many times on its way in and out of your phones´s screen.

There’s both a linear polariser and retardation layers between the surface of your phone and the display. When light hits your screen, this is what happens:

It hits the linear polariser, this vertically polarises the light. (Polarising means – roughly – aligning the wave vibration in a particular direction).

Then it hits the circular polariser retardation layer. This converts the light again, making it right-circularly polarised.

Then it hits the screen and bounces off it, switching the rotation of the light to leftist.

It goes back through the retardation layer. When this happens, the light becomes horizontally polarised.

Finally, it hits the linear polariser, since the light is horizontally polarised at this point it can be blocked entirely by this optical solution.

So why doesn’t the light from your phone’s display get blocked? Because it only goes through the second half of this journey so the light is unpolarised when it hits the final filter and goes through.

via conversations.nokia.com

I like it when small innovations can make large impact. Although I am yet to see it in practice, ClearBlack display makes is one such innovation.