A mixed-field type of Vidicon

A new type of Vidicon has been developed which uses magnetic focus and electrostatic deflection. Since both fields are superimposed in the same space, Focus Projection and Scanning (FPS) is accomplished simultaneously. In this way, Vidicon tubes of very compact size can be realized (typically a format of 1 inch by 4½ inches overall). The electron optics of this FPS system is outlined. It is demagnifying and yields excellent landing and edge-focus performance. Signal output is high (0.5 µA), and resolution in excess of 800 TV lines has been realized in a 1-inch envelope with 350 volts as the highest voltage. For a tube of given size, various performance factors such as resolution, shading, and deflection sensitivity can be balanced by design such as to enhance some factors at the expense of others. This mutual interdependence is briefly discussed. It is also shown that the ceiling of performance for this combination of crossed fields is inherently higher than for similar devices using sequential, rather than simultaneous, focusing and deflection.