Assignment 3

Color Television Picture Tube

Diagram of Color CRT© http://www.danalee.ca/ttt/monitors_and_television_sets.htm

How it Works

Colored picture tubes have two kinds of fluorescent screen structures, known as the dot phosphor, and the strip phosphor. In both cases, the chemical compounds that convert electron-beam energy into light of the additive primary colors (red, green, blue), are deposited on the inner face of the glass picture tube in precision arrangements in dots or stripes of alternating colors.

At the rear of the picture tube is the electron gun, which produces three separate beams of electrons. These three beams hit the colored dots, and the tube is so designed that each beam can hit dots of only one color; a mask prevents each beam from striking the others' color dots.

Because the colored dots are so small that they cannot be seen separately by the viewer, the effect is three superimposed images in the primary colors. By adjusting the strength of the respective beams of electrons, the relative brightness of the image produced by each can be changed. (Adapted from Monitors and Television Sets, Color Picture Tubes, ©danalee.ca/ttt/monitors_and_television_sets.htm)