Electron gun and manufacturing method therefor
AssigneeNew Japan Radio Co., Ltd.
InventorsToru Kimura, Misao Iseki, Hideyuki Obata
Life of this patent
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Abstract
An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular, a heater to increase the temperature of the cathode, and an anode to apply a positive electric potential relative to the cathode to extract electrons in a predetermined direction is provided. The cathode comprises a through hole at a central portion thereof along a central axis of the cathode, and either the cathode comprises a no-emitting layer at at least one of an opening edge on the electron emitting surface side of the through hole and an inner surface of the through hole, or the opening edge on the electron emitting surface side of the through hole is a chamfered C surface or a chamfered R surface.
Claims10
An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular, a heater, and an anode being arranged to oppose the cathode, wherein
- the cathode has a through hole along a central axis of the cathode at a central portion of the cathode;
- and
- the cathode has a no-emitting layer, wherein the no emitting layer is provided at an opening edge part of the through hole on the electron emitting surface side and/or at an inner surface of the through hole.
Dependencies are inferred from the claim text.