| 摘要 |
PURPOSE:To aim at both simplification and cost reduction tor the device in the title owing to complete negation of necessity for any cooling device such as water-cooled pipes etc., by composing the coil of each part of an electron lens system, of ceramic insulating wires with high heat resistance. CONSTITUTION:Respective coils 2b and 3b of a condenser lens 2 and an objective 3 and a deflection coil 4 are all composed of special ceramic insulating wires to be easily put in forming process. The method for manufacturing this ceramic insulating wire is carried out in such a way that a forming process such as coil winding is applied to the wire in a step of its unburnt semi-product state where an insulating paint film layer for coating lead wires has not been put in the state of ceramics, but thereafter the paint film layer is burnt at a high temperature to be put in that state. Thus, any cooling system for cooling the coils is no more required at all and the number of turn of a coil can be reduced to increase a current value so that the size of each coil can be reduced because of simplication of the device and enhancement of the maximum allowable current value of each coil.
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