Someone on that site got UV paint madnes.Almost evrything is UV reactive.
An VFD is not as compilated as it looks.In front are hair thin wires that heat up and emit electrons in the vacum.Second is the grid wich directs the electrons to the phosphor.(the grid is used to make segments)And the final layer is the phosphor it self.It has an metal contact that atracts electrons. and wen they hit the phosphor lights up.
these work down to 12V.
I have one from an old VCR that uses 50V.I personaly dont like VFDs to much.An OLED (Organic Light Emiting Display) wod be beter.These can even be made to fold like paper.They use an aray of tini organic LEDs.Thay have an huge angle of viev.And produce nice colors.And best of all an black displayd dosent use any power (by an color LCD its that same if its White or Black)