| 摘要 |
PURPOSE: An impregnation type cathode is provided to improve focus capacity and lengthen a lifetime of a cathode by reducing a diameter of an electron beam spot. CONSTITUTION: A metal layer or a metal oxide layer(3) is formed on an electron emission surface of a cathode pallet(1). An insulating layer(6) is coated on the metal layer or the metal oxide layer(3). The insulating layer(6) is formed on a peripheral portion around a cathode including the metal layer or the metal oxide layer(3) except for a center portion of the electron emission surface of the cathode pallet(1). A vertical focus gate is formed to a vertical direction of the electron emission surface of the impregnation type cathode by forming a conductive layer(7) on the insulating layer(6). The vertical focus gate is operated by applying electric power to the conductive layer(7).
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