Cathode ray tube and intensity controlling method

摘要

Disclosed is a cathode ray tube and an intensity controlling method achieving a reduced amount of factors for correcting intensity prepared and capable of performing proper intensity control so that the joint portion of split picture planes is inconspicuous from a viewpoint of intensity. With respect to the direction of overlapping a plurality of split picture planes, only correction factors at representative signal levels are pre-stored as a basic factor table (S107). Any of the factors at the other signal levels is obtained by performing an interpolating operation (S105) using the basic factors in the basic factor table. The value of the signal level of a video signal referred to when the correction factor in the overlapping direction is obtained is changed by using a shift factor associated with the pixel position in the direction orthogonal to the overlapping direction. The basic factor is thereby changed according to the pixel position in the orthogonal direction. <IMAGE>