Electron gun
AssigneesTokyo Shibaura Denki Kabushiki Kaisha, Toshiba Machine Co., Ltd.
InventorsTadahiro Takigawa, Isao Sasaki, Kazuo Tsuji
Life of this patent
Estimating the term…
Abstract
An electron gun having a cathode of a lanthanum hexaboride single crystal is disclosed in which the axis of the cathode is set to such a crystal orientation that the electron beam has two intensive emission regions which are asymmetrical with each other in intensity. In the electron gun, even at a low heating temperature of the cathode, a single spot of an image by the electron beam of a more intensive emission region since the electron beam of a weaker intensity emission region is blocked by an aperture.
Claims6
An electron gun having a cathode of a lanthanum hexaboride (LaB.sub.6) single crystal, in which the axis of the cathode is set to such a crystal orientation that the electron beam has two intensive emission regions which are asymmetrical with each other in intensity.
Dependencies are inferred from the claim text.