| 摘要 |
1,074,675. Cathode-ray tubes. ENGLISH ELECTRIC VALVE CO. Ltd. Aug. 10, 1964 [Oct. 15, 1963], No. 40550/63. Heading H1D. Scan magnification is provided in a cathode - ray tube having electrostatic deflecting plates, by producing adjacent and beyond the pair of plates 1, 1A with respect to which magnification of deflection is required, a pair of magnetic fields P, Q at right angles both to the tube axis and to the direction of deflection produced by said pair of plates, the magnetic fields P, Q being parallel and of opposite polarity, one on each side of the tube axis. The magnetic fields may be produced by a permanent magnet system or, as shown, by pairs of coils 3, 3A, 4, 4A in the form of seriesconnected, printed coils on insulating supports 5, 6 within the envelope. The scan magnification may be linear, or may differ on opposite sides of the axis. A second pair of magnetic fields, perpendicular to fields P, Q may be produced beyond deflecting plates 2, 2A so that scan magnification is effected in both directions of deflection. The tube may be a display tube employed in measuring and testing instruments and may comprise a transverse electrode close to the screen for post-deflection acceleration and a conductive wall coating surrounding the space between the deflecting plates and this electrode. |
