| 摘要 |
PURPOSE: A cathode oxide is provided to increase a density of current by using an electron emission material layer of a needle type. CONSTITUTION: A cathode oxide comprises a metal body, an electron emission material layer, and a heating portion. The electron emission material layer is formed on the metal body. The electron emission material layer comprises a barium. The heating portion heats the electron emission material layer. The electron emission material layer has a structure of a needle type. The electron emission material layer further comprises an europium oxide. The amount of the europium corresponds to 0.01 to 0.2 weight% of the amount of electron emission material.
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