US 12,191,108 B2
X-ray tube
Katsunori Shimizu, Otawara (JP); Hisayuki Tamura, Sakura (JP); and Akihiro Sasabe, Otawara (JP)
Assigned to CANON ELECTRON TUBES & DEVICES CO., LTD., Otawara (JP)
Filed by CANON ELECTRON TUBES & DEVICES CO., LTD., Otawara (JP)
Filed on Mar. 11, 2022, as Appl. No. 17/692,913.
Application 17/692,913 is a continuation of application No. PCT/JP2020/034563, filed on Sep. 11, 2020.
Claims priority of application No. 2019-167643 (JP), filed on Sep. 13, 2019.
Prior Publication US 2022/0199347 A1, Jun. 23, 2022
Int. Cl. H01J 35/06 (2006.01); H01J 35/18 (2006.01)
CPC H01J 35/066 (2019.05) [H01J 35/064 (2019.05); H01J 35/18 (2013.01); H01J 2235/18 (2013.01)] 3 Claims
OG exemplary drawing
 
1. An X-ray tube, comprising:
an anode that includes a target layer that emits an X-ray when an electron beam is incident on the target layer and an outer peripheral part encircling the target layer; and
a cathode that includes a filament that emits a beam of electrons, the filament having a major axis in a first direction, and an electron convergence cup that converges the electron beam emitted from the filament, wherein
the electron convergence cup includes a first surface located closer to the anode, and an electron convergence groove opening on the first surface and housing the filament,
the first surface includes a first edge located on the opening, and a second edge located on the opening and opposite to the first edge in the first direction,
the first edge is closer to the outer peripheral part than the second edge is, and
when a distance between the first edge and the filament in the first direction is defined as a first distance and a distance between the second edge and the filament in the first direction is defined as a second distance, the first distance is shorter than the second distance, and
the second distance is 1.3 mm or more.