Patent GB-653631-A (GB)
Title: Electron beam control apparatus
IPC: H01J31/28
Filed: 1948-01-08
Abstract: 653,631. Electron beam apparatus. RADIO CORPORATION OF AMERICA..Jan. 8, 1948, No. 664. Convention date, Feb. 19, 1947. [Class 39 (i)] An electrostatic shield for screening electron beam apparatus from the magnetic deflecting coils comprises a number of sets of conducting strips, each set of which are electrically connected together. The shield may be made from kraft paper 120 which is coated on both sides with tin-foil 126, cut as shown in Fig. 5 and slotted at the sides so that, when rolled into a cylinder, the ends can be bent to form flanges which can be clamped. An image orthicon is provided with deflecting coils, 43, 60, Fig. 1, focusing coils 15, 16, 17, which can be independently excited, a supplementary focusing coil 83 and an alignment coil 70. Horizontal deflecting coils 43 are mounted on the insulating cylinder 40 through wrappings 42 of fish paper and of the shielding material, and the vertical coils 60 are arranged on further wrappings 56 of fish paper and of the shielding material and are finally covered with fish paper and acetate cloth. The coils are secured through insulating rings between countersunk metal rings 46, 49 which, with flanged rings 45, 50 clamp the flanged ends of the shields 42, 56. A metal cylinder 65 has end flanges, extending in opposite directions, and holes for housing the coil leads which are connected to terminals 67 on the insulating ring 66. The alignment coil 70 is housed between copper cylinders 71, 72 and is connected to terminals 74. Further shielding material is wrapped about the insulating cylinder 10 so that its end flanges are clamped between countersunk flanges 11, 12. The focusing coils 15, 16, 17 are mounted thereon through further wrappings and are separated by insulating-rings 18, 19, 21 and a ring 20 made of the material known under the Registered Trade Mark " Mumetal." The coils are covered alternately with insulating material and layers which consist of wound steel strips 27 spaced by waxed twine 28 and finally with acetate cloth. The focusing coil 83 is located between flanges 81, 82 on the metal cylinder 80 which fits within the cylinder 10 and houses the metal ring 85, the " Mumetal " rings 84, 92, coated with insulating material, an insulating cylinder 90 and a terminal socket 94 for the orthicon. Copper strips 93 connect the terminal sockets to terminals 94. An exploded view (Fig. 3, not shown) indicates how the various parts engage and also the main aluminium supporting plates one of which carries the hand-operated gears for adjustment of the coils, e.g. through the gear-wheels 77, 80a, Fig. 1, and also a collar which is lined with phosphor bronze cushioning-rings within which one end of the orthicon can be secured by a screw. The collar can also be adjustably rotated by hand-gearing on the supporting plate. In modifications, the cylinder 80, Fig. 1, has the major part of the surface to the left of the flange 82 cut away to join two windows which are filled with insulating material or is slotted axially to provide the fingers 156, Fig. 7, which are secured at their ends by rivets to an insulating ring 160 riveted to the end ring 151. In another form, adjacent fingers are integral with the cylinder 80 at their opposite ends.