METHOD FOR CORRECTING SCREEN GRID VOLTAGE OF COLOR PICTURE TUBE FOR COLOR TELEVISION SET HAVING AUTOMATIC CUTOFF CONTROL, TELEVISION SET AND DEVICE HAVING COLOR PICTURE TUBE FOR REPRODUCING VIDEO SIGNAL HAVING AUTOMATIC CUTOFF CONTROL

摘要

PROBLEM TO BE SOLVED: To simplify the G2 correction of a device having an automatic cutoff circuit by resetting again a control electrode to the reference potential of the control electrode after screen grid voltage is adjusted. ;SOLUTION: Voltage potential change-over is executed in the control grid G1 of a color picture tube 1 for G2 correction. Namely, screen grid voltage UG2 is increased until a flyback strip is viewed. Screen grid voltage +UG2 is reduced so that the flyback strip actually disappears or screen grid voltage +UG2 is reduced so that it can be measured by an optical sensor since the flyback strip is in a state where it is just viewed as it is. Then, screen grid voltage +UG2 is reduced by a prescribed size so that a suitable margin is given for compensating the secular change effect of the color picture tube 1 in addition to cathode voltage reservation. Then, a control electrode G1 is reset again to reference potential.;COPYRIGHT: (C)2000,JPO