| 摘要 |
PURPOSE:To obtain a highly accurate focusing characteristic by a method wherein the electron beam pass hole parts are prepared on the cylindrical bottom parts of a pair of electrodes forming the main leanses and the curl parts are prepared on the other end opening parts while being supported by the barring part ranged in a curved surface along the cylinder outer wall. CONSTITUTION:Cathode 1, the first grid 2 and the second grid 3 are prepared. The third grid 20, the fourth grid 21, the fifth grid 22 and the sixth grid 23 are made into an independent electrode electron gun structure while being prepared so that an electrostatic lens to be formed at the central pass hole part and the electrostatic lenses to be formed at both side pass hole parts may not interfere each other. For instance, the grid 23 consists of the curl parts 251-253, wherein the end-faces of the cylinder wall parts 241-243 are curled. The barring part 28 wherein the opening hole parts 261-263, whose other ends are opened, have independent electrodes respectively and ranged in a curved surface 27 fitting to the wall parts 241-243 and the flange part 29 to be planted into a glass supporter 8 while being welded into the prescribed size after fitting. In this way, the diameter of the main lens can be magnified while obtaining a highly accurate and good focusing characteristic. |
