COLOR PICTURE TUBE

摘要

PURPOSE:To produce high resolution over the entire area of the screen by installing electrode structures for generating a tetrode-lens electric field in the electron beam path located between the focusing electrodes and varying at least one of the vertical electrode voltage and the horizontal electrode voltage according to changes in the deflection angle of electron beams. CONSTITUTION:Each electrode structure 8 for generating a tetrode-lens electric field consists of a pair of semicylindrical vertical electrodes 8a and 8b and a pair of semicylindrical horizontal electrodes 8c and 8d. It is installed in such a manner as to surround an electron beam path located between the first and the second focusing electrodes 7 and 9. Voltage (V1) of at most several hundred volts is applied to the vertical electrodes 8a and 8b and voltage (V2) of at most several hundred volts is applied to the horizontal electrodes 8c and 8d. An electron beam reaching each point including that located in the periphery of the phosphor screen can be optimumly focused both horizontally and vertically by increasing only voltage (V2) as the vertical deflection angle of the electron beam increases.