# US 9,437,390 B2 · X-ray tube device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,390 B2 - Document ID: US9437390B2 - Status: Granted - Kind: B2 - Application number: 14/437,491 - Filed: 2012-10-22 - Published: 2015-10-08 - Granted: 2016-09-06 - Earliest claimed: 2012-10-22 - Assignees: Shimadzu Corporation - Applicants: Shimadzu Corporation - Inventors: Sadamu Tomita; Masaaki Ukita - Web page: https://patentgrep.com/patent/US9437390B2 ## CPC - H01J 35/147: {Spot size control} - H01J 35/153: {Spot position control} - H01J 35/16: Vessels; Containers; Shields associated therewith - H01J 35/305: {by using a rotating X-ray tube in conjunction therewith} - H01J 2235/02: Electrical arrangements - H01J 2235/16: Vessels - H01J 2235/168: against charged particles - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract An X-ray tube device according to the present invention includes a cathode generating an electron beam, an anode generating an X-ray by collision of the electron beam from the cathode, an envelope internally housing the cathode and the anode, a magnetic field generator including a magnetic pole arranged to be opposed to the envelope, generating a magnetic field for focusing and deflecting the electron beam from the cathode to the anode, and an electric field relaxing electrode arranged between the magnetic pole and the envelope, having an outer surface having a rounded shape. Thus, the magnetic field generator can be placed closer to the envelope while a tip end of the magnetic field generator is suppressed from being a discharge start point, and hence the effect of being capable of downsizing the X-ray tube device is achieved. ## Claims ### Claim 1 An X-ray tube device comprising: a cathode generating an electron beam; an anode generating an X-ray by collision of the electron beam from the cathode; an envelope internally housing the cathode and the anode; a magnetic field generator including a magnetic pole arranged to be opposed to the envelope, generating a magnetic field for focusing and deflecting the electron beam from the cathode to the anode; and an electric field relaxing electrode arranged between the magnetic pole and the envelope, having an outer surface having a rounded shape. ### Claim 2 (depends on 1) The X-ray tube device according to claim 1, wherein the outer surface having the rounded shape of the electric field relaxing electrode is arranged in a vicinity of a tip end of the magnetic pole. ### Claim 3 (depends on 2) The X-ray tube device according to claim 2, wherein the tip end of the magnetic pole is shaped to have a corner portion, and the outer surface having the rounded shape of the electric field relaxing electrode is provided to cover at least the corner portion of the tip end of the magnetic pole. ### Claim 4 (depends on 3) The X-ray tube device according to claim 3, wherein the electric field relaxing electrode is provided to cover the corner portion of the tip end of the magnetic pole and a tip end surface and a side surface that intersect with each other at the corner portion of the magnetic pole. ### Claim 5 (depends on 4) The X-ray tube device according to claim 4, wherein the electric field relaxing electrode is provided to tightly surround and cover the corner portion of the tip end of the magnetic pole and the tip end surface. ### Claim 6 (depends on 1) The X-ray tube device according to claim 1, wherein the electric field relaxing electrode is made of non-magnetic metal. ### Claim 7 (depends on 1) The X-ray tube device according to claim 1, wherein the envelope has a tubular shape housing the cathode and the anode, and the electric field relaxing electrode is annularly provided to surround the envelope having the tubular shape. ### Claim 8 (depends on 7) The X-ray tube device according to claim 7, wherein the outer surface of a tip end of the electric field relaxing electrode that is annular is formed in a convex rounded shape in a longitudinal section in a direction along a central axis line of the envelope having the tubular shape, and the outer surface of the tip end of the electric field relaxing electrode that is annular is formed of a circular inner peripheral surface in a transverse section in a direction orthogonal to the central axis line of the envelope. ### Claim 9 (depends on 7) The X-ray tube device according to claim 7, wherein a plurality of the magnetic poles are provided at prescribed angular intervals around the envelope, and the electric field relaxing electrode includes the electric field relaxing electrode that is single and annular, provided to cover the plurality of magnetic poles. ### Claim 10 (depends on 9) The X-ray tube device according to claim 9, wherein the magnetic field generator includes an annular core and the plurality of magnetic poles arranged to protrude inward from the annular core, a plurality of recess portions into which tip end portions of the plurality of magnetic poles are inserted are provided in an outer peripheral portion of the electric field relaxing electrode that is annular, and the tip end portions of the plurality of magnetic poles are covered with the electric field relaxing electrode that is annular by insertion of the plurality of magnetic poles into the plurality of recess portions of the electric field relaxing electrode that is annular. ### Claim 11 (depends on 7) The X-ray tube device according to claim 7, wherein the electric field relaxing electrode that is annular is arranged concentrically to the envelope to surround the envelope. ### Claim 12 (depends on 7) The X-ray tube device according to claim 7, wherein an inner peripheral surface of the electric field relaxing electrode that is annular is arranged such that a distance therefrom to an outer peripheral surface of the envelope is substantially constant. ### Claim 13 (depends on 12) The X-ray tube device according to claim 12, wherein the envelope having the tubular shape has a circular outer peripheral surface in a transverse section in a direction orthogonal to a central axis line of the envelope, and the inner peripheral surface of the electric field relaxing electrode that is annular has a circular shape and is arranged such that the distance therefrom to the outer peripheral surface of the envelope is substantially constant. ### Claim 14 (depends on 1) The X-ray tube device according to claim 1, wherein the electric field relaxing electrode has a convex outer surface, and the convex outer surface of the electric field relaxing electrode includes an arcuate portion covering a tip end surface of the magnetic pole. ### Claim 15 (depends on 14) The X-ray tube device according to claim 14, wherein the arcuate portion of the electric field relaxing electrode has a curvature radius larger than a half of a length of the magnetic pole in a direction along an orientation of the electron beam. ### Claim 16 (depends on 1) The X-ray tube device according to claim 1, wherein the outer surface of a tip end of the electric field relaxing electrode has a shape corresponding to an outer shape of the envelope in a direction along an orientation of the electron beam. ### Claim 17 (depends on 16) The X-ray tube device according to claim 16, wherein the envelope has a tubular shape having a circular section and has an inclined surface inclined such that a diameter outward in a direction along a central axis line is larger, and the outer surface of the tip end of the electric field relaxing electrode has a sectional shape in which an arcuate portion covering a tip end surface of the magnetic pole and an inclined portion extending substantially parallel to the inclined surface smoothly continue in a longitudinal section of the envelope in the direction along the central axis line. ### Claim 18 (depends on 1) The X-ray tube device according to claim 1, wherein a coil is wound around a base portion side of the magnetic pole, and the electric field relaxing electrode covers a tip end portion of the magnetic pole around which the coil is not wound. ### Claim 19 (depends on 1) The X-ray tube device according to claim 1, wherein the electric field relaxing electrode is arranged to cover at least a tip end surface of the magnetic pole, and a distance between the outer surface of the electric field relaxing electrode and the tip end surface of the magnetic pole is not more than a length of the magnetic pole in a direction along an orientation of the electron beam. ### Claim 20 (depends on 1) The X-ray tube device according to claim 1, wherein the envelope has a tubular shape housing the cathode and the anode centering on an axis and rotates integrally with the anode.