| 摘要 |
<p>Picture pick-up device comprising a television on camera tube having an electron gun (6) in an evacuated envelope (1) for generating an electron beam, and a photosensitive target: (3) on which the beam is focussed by focusing means (10) and across which said beam is deflected by deflection means (9) and describes a line raster, the spot of the electron beam being elongated and the longitudinal axis of the spot being perpendicular to the lines of the rastor and having a length which is substantially equal to the line spacing. When in such a picture pick-up device the elongated spot is obtained with the aid of an adjustable multipolar stigmator (15) which, viewed in the direction of propagation of the electron beam, is provided in front of the focusing (10) and deflection means (9) coaxially around the axis (5) of the envelope (1) and the electron gun (6) the shape of the spot can be adjusted in an optimum manner so that the stern waves are completely suppressed. It is possible to provide the stigmator (16) in or around the tube and to adjust it by magnetisation, if required through the wall of the envelope (1).</p> |
