| 摘要 |
PURPOSE:To decrease the number of times of discharge remarkably, by forming the surface area of, at least, the higher volage side of electrodes or where the lower voltage side and the higher voltage side are facing each other to be as large as the circumferential edge of an aperture in its maximum outside diameter, and by reducing the area of the facing surfaces between the electrodes having a large potential difference. CONSTITUTION:The facing surface 19 including an aperture 15 is formed in a size whose maximum outside diameter coincides with the circumferential edge of the aperture 15. Such 4th lattice 18 is replaced with 4th lattice of a conventional in-line type electron gun. Being thus constituted, the static-lens formed in the region of the aperture 15 is the same as the conventional one, and the focusing characteristic does not differ from that at all. On the other hand, a facing surface 19 has become remarkably small as compared with the facing surface of the conventional one, so the generation of discharging factors caused by minute projections etc. can be restrained, resulting in remarkable reduction of the discharge. |
