| 摘要 |
PURPOSE:To improve the efficiency of an internal mirror type He-Ne laser tube and to increase the lifetime of the tube by inserting a cylindrical dielectric cover to the position from a mirror base to a cathode, thereby preventing the contamination of the output side mirror due to sputter. CONSTITUTION:A dielectric cover 13 is formed in a cylindrical shape of dielectric such as glass or ceramics to suppress a discharge among the metal part of the equivalent voltage to a cathode 4 and hence the stationary part 9 of a mirror base, a soft ring 10 and a movable unit 5 in such a manner that the interval between the metal part and a fine tube 2 is increased as long as possible to be interrupted and the end of a mirror M2 side is approached to the mirror M2 as near as possible in a range that the tilting of the mirror M2 is not obstructed. Since the end of the tube side of the cover 13 is intruded into the cathode 4, metallic vapor produced from the cathode 4 or the like is stopped by the cover 13, and does not reach the mirror M2. |
