| 摘要 |
An electron gun includes a grid electrode having a thin plate portion in which an electron beam aperture is formed, wherein the thin plate portion is formed by using a die and punch die to bulge a portion of a metal plate in the plate thickness direction to such an extent as to correspond to the desired dimension of the thin plate portion to form a bulged portion and cutting the bulged portion. With this configuration, it is possible to eliminate a problem of the related art thin plate portion of a grid electrode for an electron gun formed by coining work, which is a rib is formed around the thin plate portion, to make the gap between the thin plate portion and a cathode narrower, since the diameter of the thin plate portion can be enlarged, and to provide beam apertures at arbitrary positions of the thin plate portion.
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