How does a color image appear on a TV screen?

There are three electron-beam guns in the picture tube of a color TV. The simultaneous movement of three electron beams along the lines of the frame will be created by the action of magnetic fields from the coils. Each of the three electron beams creates its own image on the screen – red, green, blue. These images are obtained separately because each of the three beams passes through small holes in a special screen and falls into designated cells only for them, covered with different crystals that glow under the impact of electrons in red, green and blue, respectively.