[muti]

See the image and caption at the top of the article

  Images printed with structural colour ink can be made both highly transparent to transmitted light (top) and at the same time reflect light from above in vivid colours (bottom) – two properties that are typically considered mutually exclusive

The printing on the phone is not visible when the phone display is on as the structural printing is highly transparent. When the display is off, the printing is visible because of the reflected light.

[MoonWalk]

Yes, thanks; but that's neither a "smart" display nor a means to show anything but a single, static printout of "information" when the display is off.