US 12,272,514 B2
Electron gun
Ruiying Song, Shanghai (CN); and Peng Cheng, Shanghai (CN)
Assigned to SHANGHAI UNITED IMAGING HEALTHCARE CO., LTD., Shanghai (CN)
Filed by SHANGHAI UNITED IMAGING HEALTHCARE CO., LTD., Shanghai (CN)
Filed on Dec. 11, 2022, as Appl. No. 18/064,280.
Application 18/064,280 is a continuation of application No. PCT/CN2020/096230, filed on Jun. 15, 2020.
Prior Publication US 2024/0006142 A1, Jan. 4, 2024
Int. Cl. H01J 3/02 (2006.01); H01J 1/02 (2006.01)
CPC H01J 3/029 (2013.01) [H01J 1/025 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An electron gun, comprising:
a cathode with an emitting surface configured to emit electrons, the cathode including a through hole that goes through the cathode and is configured to allow back-streaming electrons of the emitted electrons to pass through;
an anode configured to attract the emitted electrons from the cathode to the anode and focus the emitted electrons into an electron beam; and
a grid structure configured to facilitate the focusing of the emitted electrons, the grid structure being positioned corresponding to the through hole; and a grid electrode including a plurality of first meshes configured to allow the electrons emitted from the cathode or the back-streaming electrons to pass through, wherein the plurality of first meshes include a center mesh corresponding to the through hole, the center mesh is configured to prevent the back-streaming electrons from impacting the grid electrode, and the center mesh is centered on a common axis of the electron gun.