Abstract: A metal cathode for an electron-emission device, and an indirectly heated cathode assembly employing the metal cathode where the metal cathode is formed of a quaternary alloy including 0.1-20% by weight barium (Ba), 0.1-20% by weight a metallic mobilizer facilitating Ba diffusion, a metal with a difference in atomic radius of at least 0.4 Angstrom from the atomic radius of platinum (Pt) or palladium (Pd), the metal being in the range of 0.01 to 30% by weight, and a balance of at least one of Pt and Pd. The metal cathode has a low operating temperature due to its reduced work function with improved current emission capability. The metal cathode can be used for a longer lifetime at high current density. Therefore, the metal cathode can be used effectively in electron-beam devices, such as a Braun tube or picture tube, satisfying larger size, longer life span, high definition, and high luminance requirements of the devices.

Abstract: An indirectly heated metal cathode for an electron tube includes a metal sleeve of an Mo material, a metal emitter disposed on the metal sleeve and including Pt or Pd as a main component; and a buffer layer between the metal sleeve and the metal emitter. The buffer layer prevents Mo, an element of the metal sleeve, from diffusing into the emitter during the operation of the metal cathode so that electron-emitting performance does not decrease rapidly with operating time due to an increase in a work function. Therefore, the metal cathode satisfies a long life span requirement for large scale and high definition electron tubes.

Abstract: A cathode for an electron tube, including a metal base and an electron-emitting material layer coated on the metal base, where the electron-emitting material layer contains a needle-shaped conductive material and the surface roughness corresponding to a distance between the highest point and the lowest point on the surface of the electron-emitting material layer is controlled to be under 10 microns. A needle-shaped conductive material is contained in an electron-emitting material layer to effectively form a conductive path, thereby minimizing the generation of Joule heat due to self-heating of the electron-emitting material layer. Also, grain and pore sizes of the electron-emitting material layer are uniformly controlled and the density and porosity of the electron-emitting material layer are also controlled, thereby improving the density and surface planarity of the cathode compared to the conventional cathode manufactured by a spraying method.

Abstract: A metal cathode for an electron-emission device, and an indirectly heated cathode assembly employing the metal cathode where the metal cathode is formed of a quaternary alloy including 0.1-20% by weight barium (Ba), 0.1-20% by weight a metallic mobilizer facilitating Ba diffusion, a metal with a difference in atomic radius of at least 0.4 Angstrom from the atomic radius of platinum (Pt) or palladium (Pd), the metal being in the range of 0.01 to 30% by weight, and a balance of at least one of Pt and Pd. The metal cathode has a low operating temperature due to its reduced work function with improved current emission capability. The metal cathode can be used for a longer lifetime at high current density. Therefore, the metal cathode can be used effectively in electron-beam devices, such as a Braun tube or picture tube, satisfying larger size, longer life span, high definition, and high luminance requirements of the devices.

Abstract: An indirectly heated metal cathode for an electron tube includes a metal sleeve of an Mo material, a metal emitter disposed on the metal sleeve and including Pt or Pd as a main component; and a buffer layer between the metal sleeve and the metal emitter. The buffer layer prevents Mo, an element of the metal sleeve, from diffusing into the emitter during the operation of the metal cathode so that electron-emitting performance does not decrease rapidly with operating time due to an increase in a work function. Therefore, the metal cathode satisfies a long life span requirement for large scale and high definition electron tubes.