| 摘要 |
PURPOSE:To improve circularity of the opening at the base of the cylindrical portions of the electrode and thereby to improve the focusing characteristic, by providing at the circumferential portion at the base of the central cylinder with a groove in such a deformed ring shape that the grooved region disposed toward the longer side of the electrode is made wider than that disposed toward the shorter side of the same. CONSTITUTION:The interior of the opening at the base of the cylindrical portions 1a-1c is provided with a taper 4 by press working and, at the same time, ring-shaped grooves 5a-5c are formed at the circumferential portions at the base of the cylindrical portions 1a-1c, whereby the electrode 6 is formed. While the grooves 5a, 5c provided at the circumferential portions at the base of the cylindrical portions at both ends 1a, 1c are formed in a circular ring shape, the groove 5a provided at the circumferential portion at the base of the central cylindrical portion 1b is formed in such a ring that the groove region disposed toward the longer side of the electrode is wider than that disposed toward the shorter side of the same. By this arrangememt, the circularity of the opening at the base of the cylindrical portions is improved and an electrode for the electron gun having an excellent focusing characteristic can be provide. |
