| 摘要 |
994,206. Electron image tubes. FERNSEH G.m.b.H. May 10, 1963 [May 12, 1962], No. 18601/63. Heading H1D. In either an image orthicon pick-up tube or an image converter tube which is provided with a long main focusing coil 5, an auxiliary coil 7 is provided adjacent the photocathode 10 to overcome the magnetic field curvature which would otherwise occur at the edges of the picture area due to the main coil alone, the auxiliary coil being traversed by a current in the same direction as that of the main coil and having its outer margin separated from the main coil by a distance which is at least as great as the radial winding height of the auxiliary coil. A further auxiliary coil may be fitted in the space 8 of the frame 6 to compensate for the effect of the focusing field produced by the auxiliary coil 7 at the centre of the photocathode. |
