Originally Posted by Penforhire
Technically there is a diffraction grating with the glass. Their teardown did not try to detect whether it is embedded, attached, or somehow etched onto the glass. They shined a laser through the combined layers.
Hum. Thanks for that although I have to admit I don't really understand the physics. Sounds like they might have etched the glass or attached something to it but we don't know how they do it.
I read somewhere that B&N patented their solution. It will be interesting to see what Amazon comes up with.