| 摘要 |
<p>Display tube such as a projection television display tube or a DGD tube (DGD=Data Graphic Display), including an electron gun (5) in an evacuated envelope (1) for generating an electron beam (6) which is focussed to a spot (8) on a display screen (7) with the aid of an electrostatic focussing lens (27, 30) and which is deflected across the display screen (7) in two mutually perpendicular directions (x, y). If a correction structure (37) consisting of magnetic half-hard material is provided in such a tube in the proximity of the focussing lens (27, 30) and coaxially of the gun axis (20) in which at least one magnetic 2N pole (N>/=2) is induced for correcting spot shape errors, a high spot quality can be realized with low-cost deep-drawn lens electrodes (27, 30).</p> |
