| 摘要 |
475,527. Cathode-ray tubes. FERNSEH AKT.-GES. May 22, 1936, No. 14529. Convention date, May 23, 1935. [Class 39 (i)] A magnetic device for deflecting an electron beam in an electron-discharge apparatus comprises a hollow ferro-magnetic member having one or more deflecting coils on its inner surface. The member 1, Fig. 3, carries a coil 4 of trapezoidal cross-section and is in the form of a truncated square pyramid having apertures 2, 3 through which the electron beam enters and emerges. If the device is used in television apparatus, the aperture 3 is preferably a rectangle having the ratio'of its sides equal to that of the sides of the image. In a modification for deflecting a beam in two co-ordinate directions, the device comprises two intersecting portions of rectangular pyramids each having a coil. In a further modification, Fig. 5, for use within the evacuated space of an electrondischarge device, a coil 3 is wound on a frame 4 of heat resisting material, e.g. glass or ceramic material carrying two square plates 5 notched to retain the windings. The ray enters through a circular bush 6 in one of the plates and emerges through a square or rectangular frame 7. Insulating plates 8 are placed over the winding and a second coil 9 at right-angles to the first is wound on the frame, the whole being inserted in a ferro-magnetic casing. The coil may be insulated with copper oxide or carbonate which may be produced while the device is in the annealing oven by the admission of air or carbon dioxide, or a layer of waterglass mixed with an insulating powder such as chalk may be used. The magnetic casing should have low hysteresis and eddy current losses and may be of granular material mixed with a binding agent. Specification 449,533 is referred to.
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