Found a modern day field sequential color tv

[old_tv_nut]

The difference between a filter and a shutter:

Filter states: clear, color (in the patent, the color state is: not transmitting light of two primary colors, but only of one primary color). It is also possible to make filters that would stop one primary color and transmit two, so the three would individually be yellow, cyan, and magenta. Then, to get additive red, green blue, you would have to activate two filters at a time.

Shutter states: clear, black (the color of the color state is black - not transmitting any light of any color).