''Processing difficulties: The LGP needs to have printed black dot patterns on one side to obtain flat brightness. Dot printing on glass substrates is more difficult than on resin.''

We can print on DG, we know it is a propriatary resin n probably very close to if not an acrylic.

http://www.displaysearchblog.com/2015/01/glass-for-backlights-a-possible-game-changer-for-lcd-and-oled/

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