Recently, someone asked me to explain what is ClearBlack Display. I can only say the black is black and the fonts are very clear on the phone. That is what I see from the phone and not the technology behind Clear Black display. Thanks to Nokia, I am able (almost) to understand how it works.
Based on the picture above, this is how Nokia explained.
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.
Could you understand? I never thought that it would need so many layers and using polarization theory to get that effect.