| 摘要 |
PROBLEM TO BE SOLVED: To avoid the direct collision of heavy positive ions released from built-in articles against the surface of a negative electrode and thereby prevent the degradation of the electron emission capability of the negative electrode in using it by avoiding the electron beam emission at least to the central part of the image plane of a cathode-ray tube during raster aging. SOLUTION: When respective electron beams 5-7 for blue, green and red colors are emitted during raster aging, positive ions of plasma emitted from built-in articles such as a fluorescent surface 4 and a color selection mechanism 8 return and directly collide with respective negative electrodes KB, KG, KR for blue, green and red colors, and positive ions from the built-in articles, due to respective beams 5'-7' for blue, green and red colors for scanning the peripheral part of the image plane go along traveling directions 9 of the positive ions different from the trajectories of electron beams having light mass. By restraining the electron beams 5-7 from being emitted to a predetermined region of the display screen in which the positive ions emitted from the built-in articles may collide with the respective negative electrodes, inconveniences that the positive ions directly collide with the surfaces of the respective negative electrodes during the raster aging can be reduced.
|
