Image pickup apparatus

Abstract From the Canadian patent

Control circuit for use with an image pickup tube permits highlights of an image to be scanned appropriately by a scanning electron beam by increasing the beam current fed to the cathode of the image pickup tube and prevents unwanted oscillations typically found when such beam currents are increased. The control circuit first determines whether the output from the image pickup tube exceeds a predetermined level and produces a control signal to be added to the normal beam current and also uses this control signal to control a vertical deflection circuit to shift the scanning electron beam upwardly toward a region on the photoelectric transducer of the image pickup tube that has already been …