The CBS-Colortron: A Color Picture Tube of Advanced Design

This paper describes a three-gun, tricolor picture tube of basically improved design. Its picture is presented on phosphors appplied directly to the curved internal face of the tube. With a curved screen, a curved mask which is self-supporting is used. The mask and the springs to hold it in place weigh only six ounces. This simple, light, yet rugged structure is mounted directly on the face plate. Three small "VI"-shaped surfaces on the mask rest on three hemispheres molded directly on the glass to locate the mask precisely. No adjustment is required at assembly. The phosphor dots are placed directly on the curved glass face plate by a photographic process, using the individual mask belonging to that tube as a negative. The screen will always exactly register with its mask because they are images of one another. The curved screen face plate serves also to close the envelope just as it does in the black-and-white tube. Advantages resulting from this design are discussed. The improvements in mechanical simplicity, ease of manufacture, size, weight, thermal-stability, electron optics, picture quality, and circuit stability are shown to stem from the use of a spherical mask and a spherical face plate. The performance of a developmental tube of this design is given. The practicability of alternate forms of this tube. including rectangular screen types in rectangular bulbs is examined. The possibility of using much of the conventional factory equipment for black-and-white picture tubes to make this new color tube is discussed.