# US 10,872,741 B2 · X-ray tube > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,741 B2 - Document ID: US10872741B2 - Status: Granted - Kind: B2 - Application number: 16/227,273 - Filed: 2018-12-20 - Published: 2019-06-13 - Granted: 2020-12-22 - Earliest claimed: 2016-06-20 - Assignees: Canon Electron Tubes & Devices Co., Ltd. - Applicants: Canon Electron Tubes & Devices Co., Ltd. - Inventors: Takashi Shimono; Naoki Takahashi - Web page: https://patentgrep.com/patent/US10872741B2 ## CPC - H01J 35/064: {Details of the emitter, e.g. material or structure (H01J35/065 takes precedence)} - H01J 35/066: {Details of electron optical components, e.g. cathode cups} - H01J 35/147: {Spot size control} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract According to one embodiment, an x-ray tube includes a cathode and an anode. The cathode includes a filament coil and a focusing electrode that includes a valley bottom part, a first inclined plane rising from the valley bottom part and inclined in the direction of the anode, a first focusing groove, and a first receiving groove. The anode includes a target surface. θ1>0°. The filament coil, the first receiving groove, and the first focusing groove are positioned more to a third extended line side than a first reference plane. One end part of the first receiving groove is closer to the first reference plane than the other end part. ## Claims ### Claim 1 An X-ray tube, comprising: an anode including a target surface radiating X-rays in a main radiation direction from a first focal spot formed by collision of an electron beam; and a cathode arranged at a position opposite to the target surface of the anode, and including a first filament emitting the electron beam and a focusing electrode focusing the electron beam emitted from the first filament, the focusing electrode including a valley bottom part farthest from the first focal spot, a first inclined plane obliquely rising from the valley bottom part in a direction to the anode, a first focusing groove opened to the first inclined plane, and a first housing groove opened to the bottom surface of the first focusing groove to accommodate the first filament, wherein an axis passing through a center of the first focal spot and parallel to an X-ray tube axis is a reference axis, a plane including the reference axis and the main radiation direction is a first reference plane, and an angle formed inside by a first extending line and a second extending line intersecting on a side opposite to a side of radiating the X-rays with respect to the reference axis is referred to as a first angle θ1, where the first extending line is a virtual straight line extending from a boundary straight line between the valley bottom part and the first inclined plane along the first reference plane, and the second extending line is a virtual straight line extending from the target surface along the first reference plane and the target surface, θ1>0° the first housing groove has a long axis, the first focusing groove has a lone axis, and the long axis of the first housing groove is inclined from the long axis of the first focusing groove. ### Claim 2 (depends on 1) The X-ray tube of claim 1, wherein the valley bottom part is a line segment parallel to the first reference plane. ### Claim 3 (depends on 1) The X-ray tube of claim 1, wherein an opening of the first housing groove is parallel to an opening of the first focusing groove, and the first filament extends along a virtual plane parallel to the opening of the first focusing groove. ### Claim 4 (depends on 1) The X-ray tube of claim 1, wherein the first filament has a long axis, and a first straight-line distance from one end part of the first filament on the first extending line side to one end part of the first focal spot on the second extending line side is referred to as D1, and a second straight-line distance from the other end part of the first filament to the other end part of the first focal spot is referred to as D2, D1