Found a Sony IDX-5000 Indextron

[Captainclock]

Originally Posted by Electronic M

A world of difference. It boils down to the indextron not using a shadow mask (which means 100% gun emission hits the phosphor = brighter picture), but instead making one color phosphor glow in the just the visible color they made it also glow in (IIRC) the UV spectrum....The UV light was picked up by a photo sensor and used to control which primary color signal was sent to the single gun....It is the culmination of the research the Japanese made into making a practical version of the alternative 50's color CRT designs that the 15GP22 delta-gun CRT put a damper on the design of....

Interesting, and what 1950s Color CRT Designs was this tube trying to mimic? Just wondering because I didn't know that we had any designs like this in the 1950s for color picture tubes...