IMAGE PICKUP TUBE

摘要

PURPOSE:To reduce the spot diameter and the figure distortion during the deflection of the electron beam by making the intensity of the electron-gun-side part of the focusing magnetic field produced by the focusing coil of an MS-type image pickup tube greater than that of the other part. CONSTITUTION:A focusing coil 7 is divided into a photoconductive-film-side coil 7a and an electron-gun-side coil 72 the length of which is 0.5 to 1.0 times the length of the coil 71. The ampere-turn level of the coil 72 is adjusted to be 1.5 to 3.0 times that of the coil 71. As a result, the distribution of the focusing magnetic field on the axis becomes nonuniform and it is possible to reduce the figure distortion and the spot diameter during beam deflection to at most half and about 1/2 of those for a conventional image pickup tube having an undivided focusing coil respectively. Therefore, it is possible to produce an image pickup tube which produces minimal figure distortion and has improved uniformity of resolution for the picture screen.