Circuit arrangement for dynamic postfocusing in electrostatic focusing cathode-ray tubes

Claim 1

A DYNAMIC FOCUSING CIRCUIT FOR A CATHODE-RAY TUBE IMPLOYING ELECTROMAGNETIC DEFLECTION, SAID TUBE HAVING AN ELECTROSTATIC FOCUSING ELECTRODE, SAID CIRCUIT COMPRISING AN AMPLIFIER DEVICE HAVING AN OUTPUT ELECTRODE, A SOURCE OF OPERATING POTENTIAL HAVING FIRST AND SECOND TERMINALS, A TRANSFORMER HAVING AT LEAST FIRST AND SECOND INDUCTIVELY COUPLED WINDINGS, SAID FIRST WINDING HAVING A TAP, MEANS CONNECTING SAID OUTPUT ELECTRODE TO ONE END OF SAID FIRST WINDING, FIRST CAPACITOR MEANS CONNECTED BETWEEN THE OTHER END OF SAID FIRST WINDING AND ONE END OF SAID SECOND WINDING, SECOND CAPACITOR MEANS CONNECTED BETWEEN ONE OF SAID TERMINALS AND THE OTHER END OF SAID SECOND WINDING, BOOSTER DIODE MEANS CONNECTED BETWEEN SAID FIRST TERMINAL AND SAID TAP, DEFLECTION YOKE MEANS, MEANS CONNECTING SAID YOKE MEANS BETWEEN SAID ONE END OF SAID SECOND WINDING AND SAID OTHER ELECTRODE OF SAID SECOND CAPACITOR MEANS, BIDIRECTIONAL CURRENT CONDUCTING MEANS CONNECTING SAID FOCUSING ELECTRODE TO SAID ONE ELECTRODE OF SAID SECOND CAPACITOR MEANS WHEREBY A PARABOLIC WAVEFORM VOLTAGE IS APPLIED TO SAID FOCUSING ELECTRODE, AND MEANS CONNECTED TO SAID AMPLIFIER DEVICE FOR PERIODICALLY INTERRUPTING CURRENT FLOW TO SAID OUTPUT ELECTRODE.