Electron-gun using combined magnetic and electrostatic focussing

915,812. Electron beam apparatus. MULLARD Ltd. Sept. 23, 1959, No. 32396/59. Class 39 (1). An electron gun comprises a ferromagnetic focusing member 3 and a beam forming electrode 9 formed as a metal coating deposited on the ferromagnetic member. The ferromagnetic member may be an alloy or a ferrite and the metal deposit may be formed by plating or spraying. The deposit may follow the profile of the ferromagnetic member or may be built up to a different profile and machined. The magnetic circuit includes an annulus 31 sealed to the envelope 1. In another embodiment the central portion of the ferromagnetic member is dish shaped and the beam forming electrode 10 is also composed as a metal deposit on a ferromagnetic member. Strips of metal may be provided on the ferromagnetic members to provide electrical connections.