Method of manufacturing a cathode ray tube for displaying colored pictures

Claim 1

In the method of manufacturing a color cathode-ray tube comprisng a fluorescent screen and a support surface and a shadow mask spaced a distance q from said screen and having parallel rows of elongate apertures, the proximal ends of each pair of adjacent apertures in each of said rows being separated by a solid bridge and the centers of each of said pairs of apertures being spaced apart by a distance a, said screen being divided into strips of phosphors, each of said strips having substantially uniform width throughout its length, the steps comprising: exposing photosensitive material on the entire said surface to illumination passing through said apertures from a light source elongated in the direction parallel to said rows of apertures and spaced a distance L from said support surface, the length l of said light source being l = a · n· (L-q/q) wherein n is an integer; and moving the source of light longitudinally during exposure of said photosensitive material by a distance k, where k = a m (L-q/q) and m is an integer at least as great as 1 and not larger than n.