X-ray generating unit and radiographic apparatus

Patent metadata

Field	Value
Publication number	US-10242838-B2
Application number	US-201415039814-A
Country	US
Kind code	B2
Filing date	Sep 11, 2014
Priority date	Nov 29, 2013
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A radiographic apparatus including a target array and an X-ray detecting unit. The target array includes a plurality of targets and a forward shielding member. The forward shielding member includes a plurality of partitions. The X-ray detecting unit includes a detecting portion. The partitions each have sloping surfaces whose angles of inclination change along an array direction.

First claim

The invention claimed is:

1. An X-ray generating unit comprising:
a plurality of targets that are arrayed in a line;
a forward shielding member including a plurality of partitions that each separate adjacent ones of the targets; and
an electron source that emits electron beams to electron incident surfaces of the plurality of targets, respectively,
wherein each partition has sloping surfaces including a first sloping surface that is on a first side of the partition and that inclines at an angle of inclination with respect to a normal line normal to a corresponding one of the electron incident surfaces, and a second sloping surface that is on a second side of the partition and that inclines at an angle of inclination with respect to the normal line, and
wherein (i) the angles of inclination of the first sloping surfaces change with positions of the first sloping surfaces along an array direction in which the targets are arrayed, and (ii) the angles of inclination of the second sloping surfaces change with positions of the second slopping surfaces along the array direction, and
wherein the forward shielding member has a first slope distribution of the first sloping surfaces in the array direction and a second slope distribution of the second sloping surfaces in the array direction, and (i) the first slope distribution showing monotonically increasing or monotonically decreasing of angles of inclination in the array direction and (ii) the second slope distribution showing monotonically increasing or monotonically decreasing of the angles of inclination in the array direction.

2. The X-ray generating unit according to claim 1 ,
wherein the forward shielding member has a plurality of apertures each defined by adjacent ones of the partitions; a plurality of X-ray beams are extracted from the respective apertures; and angles formed between the normal lines and center axes of the X-ray beams, respectively, change in the array direction such that the X-ray beams are oriented toward one another and coincide one another, and
wherein (i) the angles of inclination of the first sloping surfaces change in the array direction and in correspondence with angles of the plurality of X-ray beams and (ii) the angles of inclination of the second sloping surfaces change in the array direction and in correspondence with angles of the plurality of x-ray beams.

3. The X-ray generating unit according to claim 2 ,
wherein the forward shielding member faces a detecting plane on which a coinciding area where the plurality of X-ray beams coincide with one another is formed,
wherein one of the normal lines to the electron incident surfaces that passes through an exposure center, in the array direction, of the coinciding area is defined as a central normal line, and
wherein an absolute value of the angle of inclination of each of those sloping surfaces of the partitions that faces the central normal line increases as a distance from the first and second sloping surface to the central normal line is reduced, and an absolute value of the angle of inclination of each of those sloping surfaces of the partitions that stands with its back to the central normal line decreases as a distance from the sloping surface to the central normal line is reduced.

4. The X-ray generating unit according to claim 3 , wherein an absolute value of a rate of change, with respect to a position in the array direction, in the angle of inclination of each of those sloping surfaces of the partitions that faces the central normal line decreases as the distance from the sloping surface to the central normal line is reduced; and an absolute value of a rate of change, with respect to the position in the array direction, in the angle of inclination of each of those sloping surfaces of the partitions that stands with its back to the central normal line increases as the distance from the sloping surface to the central normal line is reduced.

5. The X-ray generating unit according to claim 1 ,
wherein each pair of sloping surfaces provided on opposite sides, respectively, of a corresponding one of the center axes incline with respect to the normal line such that virtual planes extended from the pair of sloping surfaces toward a corresponding one of the targets intersect each other between a corresponding one of the electron incident surfaces and the electron source.

6. The X-ray generating unit according to claim 1 , wherein the sloping surfaces are provided only in front end portions of the partitions in a height direction.

7. The X-ray generating unit according to claim 1 ,
wherein the forward shielding member includes
a connecting portion that connects the plurality of partitions and extends in the array direction; and
the plurality of apertures defined by the partitions and the connecting portion, and

wherein the apertures are each defined by two or more inclined planes including at least a pair of sloping surfaces.

8. The X-ray generating unit according to claim 1 , wherein the each partition contains at least any one of metallic elements, which are lead, gold, platinum, silver, tungsten, molybdenum, tantalum, copper, nickel, and iron.

9. A radiographic apparatus comprising:
the X-ray generating unit according to claim 1 ; and
an X-ray detecting unit that includes a detecting portion facing the target array and including a plurality of detecting devices.

10. The radiographic apparatus according to claim 9 ,
wherein the X-ray detecting unit further includes a shielding portion provided on an outer side of the detecting portion in the array direction,
wherein the X-ray generating unit forms a main exposed area and an eclipse-attributed penumbra area on the X-ray detecting unit, the eclipse-attributed penumbra area being formed on the outer side of the main exposed area, and
wherein the shielding portion includes at least a part positioned in the eclipse-attributed penumbra area.

11. The radiographic apparatus according to claim 10 , wherein the shielding portion includes a part that is positioned on the outer side of the eclipse-attributed penumbra area in the array direction.

12. The radiographic apparatus according to claim 10 , wherein the shielding portion is provided on each of two outer sides of the detecting portion in the array direction.

13. The radiographic apparatus according to claim 10 ,
wherein the main exposed area is defined by a main exposed length Lm in the array direction, the main exposed length Lm being expressed as (n−1)×p+{Φ+(D SI /h 0 )×(Ψ−Φ)}, and the eclipse-attributed penumbra area extends from an edge of the main exposed area in the array direction and toward the outer side in the array direction by an eclipse-attributed penumbra length w min expressed as {(D SI −h 0 )/h 0 }×Φ, where h 0 denotes a height of each of the partitions extending toward a side across the electron incident surfaces from the electron source; Φ denotes a focal spot diameter of each of focal spots formed on the respective electron incident surfaces by the electron source; p denotes a focal spot pitch; n denotes a number of targets that are arrayed; Ψ denotes an aperture diameter determined by adjacent ones of the partitions; and D SI denotes a source-to-image distance by which the detecting portion is distant from the electron incident surfaces.

14. The radiographic apparatus according to claim 13 , wherein the height h 0 of the partitions, a width w 0 of the shielding portion, and a height D 0 of the shielding portion satisfy at least Expressions (1), (2), and (3), respectively, or Expressions (1), (4), and (5), respectively:

Assignees

• Canon Kk

Inventors

• Shiozawa Takashi
• Ueda Kazuyuki
• Tsujino Kazuya
• Ito Nobuhiro

Classifications

• H01J35/08 Primary

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• G21K1/02 Primary

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• A61B6/502

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• H01J2235/087

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