Design factors in television cathode-ray tubes

The paper discusses the general trend in the size of directly viewed television tubes and considers the merits of both metal and all-glass types. The alternative method of producing large pictures¿by projection¿is considered, and the techniques by which the form of receiver might be improved are given. The various types of focusing employed for television tubes are discussed, and the reasons for the choice of electromagnetic deflection are given. The electron optics of the gun is considered in detail, the method by which the existing compromise has been obtained being indicated. The theory outlined refers to both directly viewed tubes and projection tubes. It is also shown that improvements in the performance of both types of tube could be achieved by the use of higher screen efficiencies and cathodes capable of withstanding higher loadings, and by a reduction in the spot-swelling characteristics of the electron gun.