Character selector for a shaped beam cathode ray tube

摘要

A character selector for a shaped beam cathode ray tube comprising an orthogonal pair of air core deflection coils each of which consists of two identical halves formed to fit snugly over the neck of the cathode ray tube. The coils are continuous windings of electrically conductive material and comprise three sections which in operation cause an on-axis electron beam to be sequentially deflected off-axis, converged back to the axis and then referenced along the axis so that the final path of the beam, sequentially deflected on off-axis excursion paths through various shaping apertures in a stencil, is dependent of its off-axis excursion. The character selector may include magnetic material placed over at least a portion of the windings to provide a fine adjustment of the relative magnetic field strength as well as for enhancing the magnetic efficiency and shielding of the device.