| 摘要 |
PURPOSE:To eliminate the generation of deformation in a hole part of an electrode further maintain stable quality of focusing. CONSTITUTION:Two intermediate cups 14 having an electrode provided with burrings 14a are provided between a G3 electrode cup 12 and G3 electrode bottom 13. This burring 14a is utilized, and deflection of the electrode is suppressed further prescribed work can be ended without contacting the electrode to a hole part of the cup 12. Accordingly, the work can be performed without causing the deformation of a bridge 12a in the hole part of the cup 12 to obtain a stable focus characteristic. |
