Patent ID: 7414356
Filing Date: 2008-08-19
Classification: H01J

Abstract:
1. A cathode structure comprising: a heater including a columnar electric insulating material body having a diameter larger than a height and a heating wire that is partially buried and in contact with the electric insulating material body, wherein the heating wire is coiled, within the insulating material body, around a first axis; a cathode unit is disposed at a first end surface of the electric insulating material body including a metal cup and a pellet member supported in the metal cup, the pellet member containing an electron-emitting material; and a supporting metal wire attached to the cathode structure between the metal cup and the heater, wherein the heating wire leads out from a second end surface of the electric insulating material body and the first axis of the coiled heating wire is parallel to the first end surface of the electric insulating material to provide a compact configuration for the cathode structure with an enlarged heat transmitting capacity.