| 摘要 |
The invention contemplates lead-through structure for the high-voltage electrode of an electron microscope or the like, in conjunction with shaping of the high-voltage electrode and of the body of insulating material via which the lead-through is supported, in reference to metal envelope structure. The high-voltage electrode has a step-wise enlargement, and the surface of the insulating material which is exposed to the vacuum commences at the start of the step-wise enlargement. As a result, the field strength along the vacuum-exposed insulator surface is so influenced that a minimum electric field strength is produced at the boundary line between the vacuum and the high-voltage electrode. The further result is to prevent occurrence of microdischarges.
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