Triniscope

The Triniscope was an early color television system developed by RCA. It used three separate video tubes with colored phosphors producing the primary colors, combining the images through dichroic mirrors onto a screen for viewing.

As a consumer system it was enormous, expensive, impractical, and dropped as soon as the shadow mask system was successful. However, the Triniscope idea was used commercially in several niche roles for years, notably as a color replacement for the kinescope, from which it took its name.