Word: phosphorous
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...standard TV tube, the picture is formed by a slim beam of electrons scanning back and forth across the phosphor on its front face, like a garden hose washing a wall. The Willys tube works on the same general principle, but it has no large empty space. It is made of two glass plates an inch or so apart, with a vacuum between. The electron beam enters from an upper corner. The electrons move horizontally between the glass sheets and stream past metal "deflection plates...
...trick is done by a zinc sulphide "phosphor" (a substance that glows when light strikes it) sandwiched between two conducting films, one of them transparent. When an electric voltage is applied across the films, the phosphor takes energy from it and uses it to increase by "electroluminescence" the brightness of the light image...
Behind the line-covered viewing screen is a "grid" of fine parallel wires, one wire for each group of phosphor lines. At the narrow rear end of the tube is a single electron gun that shoots a slender beam of electrons through the wire grid at the viewing screen. As in all television tubes, the electron beam scans at a rapid rate, painting an ever-changing picture on the screen of phosphors...
Electron Switching. The trick in color television is to make the electrons that represent red, for example, hit the phosphor that glows in red. In the Lawrence tube, the wire grid does this switching job. It is hooked up, through the proper electronic apparatus, to the signal that comes over the air. When the signal tells it that certain electrons represent red, the wires of the grid are charged with enough electrical potential to focus the electron beam onto a line of red phosphor. When "green" electrons come along, it switches them to green phosphor, etc. So, jumping from phosphor...
...receiving set at the other end has three picture tubes. They are like black & white tubes except that each has on its face a phosphor that glows in a different basic color. Each little impulse (the colored freight cars) arriving over the beam is electronically switched to the properly colored tube. They arrive so fast that each tube-face is covered 15 times a second with a pattern of tiny dots corresponding to the blues, reds and greens in the scene being televised. The more red there is in a part of the scene (e.g., a red dress), the brighter...