Electron gun
AssigneeNEC Microwave Tube, Ltd.
InventorAkira Chiba
Life of this patent
Estimating the term…
Abstract
An electron gun also has a cathode for emitting electrons, a heater cap which contains a heater for applying the cathode with thermal energy for emitting electrons, a retainer for securing the cathode on the heater cap by clamping the peripheral edge of the cathode onto the heater cap, and a cylindrical Wehnelt supporter. The cylindrical Wehnelt supporter has a Wehnelt electrode for focusing an electron beam that is formed in such a shape that an average angle of the surface thereof with respect to an outermost shell of the electron beam matches a Pierce angle, and three or more heater cap supporters for securely supporting the heater cap at a position at which an electron emitting surface of the cathode and an opening formed through the Wehnelt electrode satisfy a predetermined perveance.
Claims10
An electron gun comprising:
- a cathode for emitting electrons;
- a heater cap which contains a heater for applying said cathode with thermal energy for emitting electrons;
- a retainer for securing said cathode on said heater cap by clamping the peripheral edge of said cathode onto said heater cap;
- and
- a cylindrical Wehnelt supporter that has a Wehnelt electrode for focusing an electron beam formed in such a shape that an average angle of the surface thereof with respect to an outermost shell of said electron beam matches a Pierce angle, and three or more heater cap supporters for securely supporting said heater cap at a position at which an electron emitting surface of said cathode and an opening formed through said Wehnelt electrode satisfy a predetermined perveance.
Dependencies are inferred from the claim text.