EP2124231A2 - Aperture for an imaging device - Google Patents

Abstract

The orifice (100) comprises an additional slit or an additional area, absorbing the small radiation (12). Each additional slit or area has two additional non-planar surfaces. The two non-planar surfaces are limited by the area absorbing the radiation. The contour of the former additional non-planar surface is described partially by a function according to the application of the assigned affine image. An independent claim is included for a method for manufacturing an orifice.

Description

The invention relates to a diaphragm, in particular for an imaging device, according to the preamble of claim 1.

Frequently the problem arises of determining the form of hidden sources of high-energy radiation of unknown structure or spatial structure. The radiation source can be, for example, the effective focal spot on the anode of an x-ray tube or surface-distributed radiating material. The latter can be radioactive waste distributed over a room in a collecting bin, whereby alleged discrepancies between declaration and actual content must be clarified. Further examples of radiation sources whose shape one wishes to image are deposits with uranium-containing ores or nuclear facilities, in which it is often not only of importance to determine the nature of the radiation, but also to determine the spatial structure of the radiation sources. In addition to the sources mentioned, which generate the high-energy radiation directly, are also those that generate them by X-ray or Gammarückstreuung.

To illustrate the shape of such radiation sources, it is obvious to apply the principle of a camera. Quite different area detectors can be used: film material, storage disks, storage foils, semiconductor flat detectors, vidicams, image intensifiers or converter foils. Since such recordings can also and especially occur in environments in which persons should not enter, if possible, the simplest operability must be ensured. The simplest functionality and handling would be to remotely place a corresponding device with a retrieval after the exposure time without any operation of any controls.

It is known to use the Lochkameraprinzip when imaging with the help of high-energy radiation. In a pinhole camera or camera obscura , a small hole on a projection surface produces an image of illuminated or radiating objects. The small diameter of the diaphragm limits the incident beam to a small opening angle and thus prevents the complete overlap of the beams in the imaging surface. Radiation from an upper portion of a radiating body is incident on the lower edge of the projection surface while, conversely, rays are incident from the lower portion the upper edge of the projection surface are mapped. Thus, each point of the object is imaged as slices on the projection surface, so that the superimposition of the slice images provides an image of the radiating body whose resolution depends on the distance of the radiating body and the shape of the diaphragm.

The problem with high-energy radiation is that, because of its high permeability, the thickness of the material for the pinhole diaphragm must be large, that is to say in relation to the half-value thickness of the intensity of the radiation used for imaging. Therefore, the achievable image quality is essentially determined by aperture diameter and material thickness and density. Often, therefore, one obtains at best a shadow image of the actual pinhole, wherein the pinhole, which is to serve for imaging, due to the wall thickness becomes a collimator, which can pass only a straight-line beam. Therefore, the aperture in the hole cameras is often trumpet-shaped with the narrow spot to the radiation source designed so as not to lose the imaging properties completely.

The DE 690 01 117 discloses a device for detecting radiation sources in real time. The device comprises a collimator which is delimited by a wall in the form of a double cone, the double cone being formed from two cones of the same opening angle, which are set opposite each other at the vertex. The vertex forms the pinhole of the resulting camera.

To increase the opening angle of a pinhole camera for high-energy radiation while maintaining a high resolution, suggests the DD 240 091 a rotating diaphragm system, which consists of several concentrically arranged around the optical axis hollow cones. Each hollow cone consists of half of the respective radiation strongly or weakly absorbing material, the hollow halves are inserted into each other so that always hollow cone halves of different materials adjoin one another.

Another mechanically moving solution is from the DE 40 00 507 known, in which a slit aperture acts like the opening of a pinhole camera. The relative movement of the slit diaphragm to the detector exposes the radiation scattered from various points of the test object to the detector. Due to the relative position of the slit, it is predetermined from which depth of the test object secondary radiation is detected by a detector.

A solution for expanding the field of view in a pinhole camera is from the DE 196 03 212 in which the core of the camera has a cylindrical borehole crystal which is terminated by a pinhole collimator, which is conically arched in the region of the borehole. In the center of the collimator is an aperture. Depending on the shape of the collimator, the field of view has an opening angle of up to approximately 120 °.

In addition, various approaches are known from the prior art to solve the problem of penetration of hard radiation for a diaphragm with the lowest possible layer thickness. Mention may be made, for example, of near-surface collimators with inclined plates, which are made of US 6,377,661 known or the use of moving collimators ( GB 1 046 337 ).

Disadvantage of all solutions described is that with high-energy radiation due to the required material thickness, a significant deviation from the ideal hole camera principle is present, except when mechanically moving solutions are used, which are very expensive.

In the published patent application DE 10 2005 029 674 A1 a shutter is disclosed which overcomes some of the disadvantages of the solutions described. The diaphragm is not based on a mechanically moving solution and can be realized with almost any material thickness, without losing its imaging properties. The diaphragm is suitable for limiting radiation originating from a radiation source, in particular high-energy radiation, and for directing it to an imaging region along an optical axis x according to the hole-camera principle. The diaphragm comprises the radiation at least partially absorbing regions, and in the diaphragm there is a gap or at least one radiation absorbing portion which has at least a first non-planar surface and a second non-planar surface which separates it from the radiation delimit at least partially absorbent areas. The contour of the first nonplanar surface may be described at least partially by a function z ( x, y ) = f ( y ) * x + n , and the contour of the second nonplanar surface is at least partially complementary to the contour of the first non-level surface.

The disadvantage of this diaphragm is that the imaging quality, the image size and the radiation yield are subject to restrictions. By reducing the gap width, the imaging quality can be increased; However, this is simultaneously the pictured Restricted range in y- direction and reduced the beam yield. Conversely, by increasing the slit width, the imaged area in the y- direction is expanded and the beam yield is increased, but at the same time the imaging quality is lowered.

The object of the invention is therefore to provide a diaphragm for a pinhole camera, which has the advantages of the published patent application DE 10 2005 029 674 A1 disclosed aperture, but achieves a better imaging quality and / or a larger imaging range and / or a higher beam efficiency.

Another object of the invention is to provide a diaphragm with better imaging quality and / or larger imaging range and / or higher beam efficiency, which after a comparison with that in the German patent application with the file reference 10 2007 057 261.3 disclosed methods of making the disclosed in the publication DE 10 2005 029 674 A1 disclosed aperture can be produced only slightly modified method.

According to the invention the objects are achieved by means of a diaphragm, in particular for an imaging device, with the features mentioned in claim 1.

In particular, the diaphragm according to the invention according to the preamble of claim 1, the advantageous features described above in the published patent application DE 10 2005 029 674 A1 disclosed aperture, wherein for the aperture according to the invention in the function z ( x, y ) = f ( y ) * x + n ( y ), the term n ( y ) is not necessarily constant, but may have a dependence on the coordinate y ,

The description of the surface contours is based on a three-dimensional Cartesian coordinate system whose origin lies on the first non-planar surface without restriction of generality (cf. FIG. 2 ). The mode of operation of the diaphragm can be explained by considering a beam with a directional vector (1, y _s , z _s ), ie a beam which propagates in the direction of the positive optical axis x. For those ray bundles whose y-component vanishes and which can be described by a direction vector (1,0, tan ψ) (cf. FIG. 3 ), there exists a straight line on the first non-planar surface, which runs parallel to the ray bundle, if f (y) = tan ψ holds. If f (y) is a strictly monotonically increasing or decreasing function, then it is only possible to see through the resulting gap in a straight line at one point. In other places, the radiation is absorbed more strongly.

The gap already described or the region which absorbs little radiation is referred to here as the first gap or the radiation having a low absorption, since the diaphragm according to the invention has at least one additional gap or at least one additional region which absorbs the radiation to a small extent.

The low radiation absorbing regions may be filled with a suitable material which absorbs the relevant radiation less than the radiation at least partially absorbing regions, the material being in the form of a separate insert or a coating applied to at least one of the non-planar surfaces can. In the following, a gap is also to be understood as meaning a region which absorbs the radiation to a low degree and which is filled with material. By non-planar surfaces is meant any surface that is not flat, such as curved and curved surfaces.

In the following, the term "affine mapping" refers to an image of the three-dimensional space on itself, which maps each straight line to a straight line. Such a map can be vectored with respect to a given affine, ie, rectilinear, coordinate system by a mapping rule of the form x → A x + b describe, where x the vector describing the point to be imaged, A any regular 3x3 matrix and b is an arbitrary three-vector. The term "isometry" refers to an isometric mapping of the three-dimensional space to itself, ie a rigid body movement that leaves distances and angles invariant. An isometry is an affine image in whose vector representation with respect to a Cartesian coordinate system the matrix A is orthogonal. The term "shear along the direction A parallel to the plane B" denotes an affine map which shifts each point of the space along the direction A parallel to the plane B by a distance proportional to the distance of the point from the plane B.

All these figures depict the entire three-dimensional space on itself in a mathematical sense, ie assign a point of three-dimensional space to each point of the three-dimensional space. By applying such a map g to the contour of a surface, it is to be understood that each point p of the contour is mapped to the point g (p) which the map g associates with it. The result of applying the mapping to the contour is the contour formed by the dots so depicted.

The fact that at least one additional gap is present in the diaphragm, it is achieved that additional radiation reaches the imaging region, whereby a larger imaging range and / or a higher beam efficiency can be achieved. Due to this, the gap width can be reduced to achieve a better image quality. Furthermore, when several columns are packed tightly, larger wall thicknesses can be realized, such as e.g. with gamma radiation are necessary.

By virtue of the fact that each additional gap has at least one first additional non-planar surface and a second additional non-planar surface which delimits it from the regions which at least partially absorb the radiation, for each additional gap an associated affine image exists, the contour of the first additional nonplanar surface after application of the associated affine map can each be at least partially described by the same function z ( x , y ), by which the first non-planar surface of the first gap can be at least partially described, and the contour of the second additional non-planar surface is at least partially complementary to the contour of the first additional non-planar surface, it is achieved that the additional column each have similar imaging properties as the first gap.

In a preferred embodiment of the invention, it is provided that the set of affine mappings which comprises the identity mapping for the first gap and the associated affine mapping for each additional gap can be placed in a sequence in such a way that an affine image generating the sequence exists, such that for each pair of affine maps following each other in the sequence, the affine image of the pair following in the sequence is obtained by concatenating the affine image of the pair preceding the sequence with the sequence-generating affine map. This ensures that the sub-images caused by the individual gaps are in a particularly simple and regular relationship to each other.

Preferably, for each additional gap, the associated affine map is an isometry. As a result, it is achieved that the additional gaps can be formed by applying a method, which essentially corresponds to the method used to form the first gap, after a movement of the diaphragm corresponding to the respective isometry has been carried out. In addition, if the sequence of affine images is generated by an isometry, it is further achieved that the formation of all gaps in each case the same movement before application of the applied method for forming a gap method is executed.

In a further preferred embodiment of the invention, it is provided that for each additional gap, the associated isometry can be described in each case as concatenation of a first isometry and a second isometry, each of the first and second isometries each having either a translation along a coordinate axis or a rotation around one is parallel to a coordinate axis or coincident with a coordinate axis axis. This ensures that the imaging properties of the sub-images caused by the additional column are in a particularly easy-to-describe relation to the sub-image caused by the first gap and that the movements required to form the additional column are particularly simple and accurate.

In particular, for each additional gap, each of the first and second isometries may be a rotation about an axis parallel to a coordinate axis or coincident with a coordinate axis. It is thereby achieved that the description of the relation in which the imaging properties of the sub-images caused by the additional column stand for the subimage caused by the first gap is further simplified and that no shifts are required to form the additional column.

In a preferred embodiment, for each additional gap, the first isometry is in each case a rotation about a respective angle α about a first axis, which lies in the x - y plane and runs parallel to the y- axis or coincides with the y -axis, and the second isometry each rotation about a respective angle β about a second axis, which lies in the xz plane and parallel to the z- axis or coincides with the z- axis. It is thereby achieved that the sub-images caused by the gaps adjoin one another at least at a predetermined distance from the y - z plane and result in a consistent overall image there. The angle β can each be 0 °.

The first axis can coincide with the y- axis. It is thereby achieved that the sub-images caused by the gaps adjoin one another independently of the distance from the yz-plane and result in a consistent overall image.

In a further preferred embodiment of the invention, the associated affine image is in each case a shear for each additional gap. In a particularly preferred embodiment of the invention, the shear is in each case a shear in the y- direction parallel to the y- z plane. This ensures that the imaging surface is increased irrespective of the distance of the imaging plane to the diaphragm center and the distortions or blurring in the superposition of the partial images caused by the column are particularly low.

In a further preferred embodiment of the invention, it is provided that the function z ( x , y ) has the form z ( x, y ) = A * x + B * y + C * y * x + n . A, B, C and n are constants. As a result, a particularly simple, linearly varying surface contour is specified, by which the hole camera principle can be ensured. The passage opening in the first gap, which allows a beam to pass with the directional vector (1,0, tan ψ), in this arrangement moves continuously from one side of the aperture to the opposite side for an increasing viewing angle ψ.

Preferably, the relationship between the respective angles α and β and the constant B is α = B * β. This ensures that the same mathematical relationship between the direction vector and the imaging location exists for all the columns.

The constant A may have the value 0, and the constant B may have the value 0. In this case, the shape of the first non-planar surface corresponds to the shape of the first nonplanar surface of the laid-open publication DE 10 2005 029 674 A1 disclosed aperture.

In a preferred embodiment of the invention, it is provided that the regions which at least partially absorb the radiation are arranged in a region with x > x ₀ , where x _{0 is} a constant value with x ₀ ≥ 0. It is thus achieved that the region around x = 0, in which the surface contours rotated by the y- axis would overlap, lies outside the at least partially absorbing regions, so that the at least partially absorbing regions remain coherent despite the additional gaps.

It is further preferred for each additional gap that the contour of the second additional non-planar surface relative to the contour of the first additional non-planar surface is at least partially in the same position in which the contour of the second non-planar surface is relative to the contour of the first non-planar surface located. This ensures that the mapping properties of the column match and all columns can be formed using the same procedure.

ist. Wenn die Spaltbreite h(y) so gewählt ist, dass der
genannte Ausdruck konstant ist, werden Strahlenbündel gleicher Intensität mit der gleichen Abbildungsqualität abgebildet.In a preferred embodiment of the invention, it is provided that the first gap has a gap width h (y) which is essentially constant in a direction parallel to the optical axis x. The visible in the direction of the beam passage then has a size which is proportional to the expression $\frac{H^2\left(y\right)}{\frac{\partial f\left(y\right)}{\partial y}}$

is. If the gap width h (y) is chosen so that the
is constant, beams of equal intensity are imaged with the same imaging quality.

It is further preferred that the width of the column is variable. As a result, the imaging properties of the diaphragm can be adapted to different situations, in particular to different intensities of the investigated radiation sources.

Since the first gap fulfills the ideal hole camera principle only for beam bundles whose directional vectors lie in the xz plane, it is provided in a further embodiment of the invention that the radiation-absorbing regions are arranged rotatably about the optical axis x, so that the Column can be rotated. Thus, multiple images of an object can be made, each containing a line for which there are ideal imaging properties.

As the building material for the diaphragm, all materials are in question, which are able to absorb the radiation emitted by the radiation source effectively. In the case of X-rays or gamma rays, these are heavy metals with a high atomic number, for example copper or tungsten. For neutron beams, however, plastics with a high hydrogen content, for example polyethylene, are suitable.

As mentioned above, it is an advantageous feature of the diaphragm according to the invention that the additional gaps can be formed by the same or a similar method as the first gap. In particular, the column according to the in the German patent application with the file number 10 2007 057 261.3 disclosed methods are formed.

The invention therefore also provides a method of manufacturing a shutter as described above in which relative movement is performed between a cutting tool capable of cutting along a straight line and a workpiece such that the cutting tool traverses the workpiece a line intersecting a beam path in the diaphragm to be made, wherein the relative movement is repeated at least once, and wherein before each repetition of the relative movement, the workpiece is moved.

Preferably, the workpiece is cut along a fixed first direction. Furthermore, it is preferred that a rotational movement of the workpiece about a first axis of rotation, which runs along a second direction perpendicular to the cutting direction of the cutting tool, and at the same time a translational movement of the workpiece along the second direction are performed. Preferably, the rotational movement and the translational movement of the workpiece are linearly coupled.

Further advantageous embodiments of the invention will become apparent from the features mentioned in the dependent claims.

Figur 1

eine bildgebende Einrichtung mit einer erfindungsgemäßen Blende;

Figur 2

eine nicht-ebene Oberfläche mit eingezeichnetem kartesischen Koordinatensystem und eingezeichneten Strahlengängen;

Figur 3

ein kartesisches Koordinatensystem mit eingezeichnetem Richtungsvektor in der x-z-Ebene;

Figur 4a, b

eine Blende gemäß Offenlegungsschrift DE 10 2005 029 674 A1 aus zwei Betrachtungsrichtungen;

Figur 5

eine Blende gemäß Offenlegungsschrift DE 10 2005 029 674 A1 mit gekipptem Spalt;

Figur 6

(schematisch) eine Testanordnung;

Figur 7

eine Perspektivansicht einer Blende gemäß einer ersten Ausführung der vorliegenden Erfindung;

Figur 8

eine Querschnittsansicht der Blende von Figur 7 in Schnittebene A in Blickrichtung a;

Figur 9

eine Draufsicht der Zentralstrahlen der Blende von Figur 7 in Blickrichtung b;

Figur 10

eine Perspektivansicht der Blende von Figur 7 und ihrer Zentralstrahlen;

Figur 11

eine Perspektivansicht einer Blende gemäß einer zweiten Ausführung der vorliegenden Erfindung;

Figur 12

eine Perspektivansicht zur Verdeutlichung des Aufbaus der Blende von Figur 11;

Figur 13a,

b eine Draufsicht in z-Richtung einer in einer dritten Ausführung der vorliegenden Erfindung verwendeten Scherung;

Figur 14

eine Perspektivansicht zur Verdeutlichung des Aufbaus einer Blende gemäß der dritten Ausführung der vorliegenden Erfindung; und

Figur 15

eine Perspektivansicht einer Blende gemäß einer vierten Ausführung der vorliegenden Erfindung.

The invention will be explained in more detail in embodiments with reference to the accompanying drawings. Show it:

FIG. 1

an imaging device with a diaphragm according to the invention;

FIG. 2

a non-planar surface with drawn Cartesian coordinate system and marked beam paths;

FIG. 3

a Cartesian coordinate system with a drawn direction vector in the xz plane;

FIG. 4a, b

a panel according to published patent application DE 10 2005 029 674 A1 from two viewing directions;

FIG. 5

a panel according to published patent application DE 10 2005 029 674 A1 with tilted gap;

FIG. 6

(schematically) a test arrangement;

FIG. 7

a perspective view of a panel according to a first embodiment of the present invention;

FIG. 8

a cross-sectional view of the aperture of FIG. 7 in sectional plane A in the direction of view a;

FIG. 9

a plan view of the central rays of the aperture of FIG. 7 in the direction b;

FIG. 10

a perspective view of the aperture of FIG. 7 and their central rays;

FIG. 11

a perspective view of a panel according to a second embodiment of the present invention;

FIG. 12

a perspective view to illustrate the structure of the aperture of FIG. 11 ;

FIG. 13a,

b is a z-direction plan view of a shear used in a third embodiment of the present invention;

FIG. 14

a perspective view illustrating the construction of a diaphragm according to the third embodiment of the present invention; and

FIG. 15

a perspective view of a panel according to a fourth embodiment of the present invention.

FIG. 1 illustrates the Lochkameraprinzip at an imaging device 200. From a radiation source 10, for example, a test body, high-energy radiation 12, in particular X-rays or gamma rays, emitted. The radiation 12 strikes a diaphragm 100, by which it is limited and directed along an optical axis x according to the Lochkameraprinzip on an imaging region 14. The imaging region 14 is typically a projection surface on which an image of the test body 10 is generated. In the imaging region 14 is a receiving unit 16 which is sensitive to the radiation 12, in particular a detector or a camera.

The diaphragm 100 according to the invention comprises the radiation 12 at least partially absorbing regions. A first radiation 12 absorbing region 18 is in FIG. 2 shown. It is delimited by a first non-planar surface 20 of a slit or the region 12 of low-absorbing radiation (not shown). The position of the Cartesian coordinate system is chosen so that its origin lies on the first non-planar outer surface 20, without limiting the generality. The x-axis coincides with the optical axis.

The surface contour of in FIG. 2 can be described by a function of the form z (x, y) = C x y x, ie in this case z (x, y) = f (y) · X + n (y) with f (y) = C · y and n (y) = 0. For the in FIG. 2 shown surface C <0; however, C> 0 can also be selected. The radiation absorbing portion 18 in this case is a parallelepiped, with respect to the coordinate system symmetrical body of suitable absorbent material (width a, depth b). For hard radiation this is a heavy metal with the highest possible density, for example copper or tungsten. In FIG. 2 are ray paths 22a, b shown, which run parallel to the side edges 24a, b of the radiation-absorbing portion 18. The beam paths 22a, b correspond to direction vectors (1, 0, ± aC / 2). For every direction vector (1, 0, z) for which - aC / 2 <z <aC / 2, there is exactly one parallel edge on the non-planar surface 20. For each direction vector with non-vanishing y-component, on the other hand the corresponding lines on the non-planar surface 20 are not linear.

FIG. 3 shows a Cartesian coordinate system with drawn direction vector, which lies in the xz plane and forms an angle ψ with the x-axis. Radiation with such a direction vector whose y component disappears passes through the diaphragm according to the invention at a position y at which f (y) = tan ψ.

FIGS. 4a, b show first for illustration for two viewing angles, a diaphragm according to published patent application DE 10 2005 029 674 A1 with a single gap 32 and two radiation-absorbing areas 18 and 26. Depending on the viewing direction, a view through the gap 32 in a straight direction is possible only at one point. In the respective direction thereby appears a parallelogram-shaped passage opening 34. The cleavage direction can optionally be horizontal ( FIG. 4 ) or vertical ( FIG. 5 ) be aligned. On the basis of a second image with such rotated aperture, distances to the object can be estimated on the basis of large-area contours and, if necessary, measured.

FIG. 6 shows schematically a test arrangement. A continuously radiating, powerful x-ray tube 46 generates radiation, which is hidden by an all-round shield, here a lead wall with window 48. The radiation passing through the window of the lead wall 48 falls onto an aluminum plate as scattering filter 50. The actual test object 10 is arranged between the scattering filter 50 and the diaphragm 100 according to the invention, which is integrated in a shielding wall 30 made of lead. As the detector 16 on the projection surface 14, an X-ray film or an image storage film (English: phosphor imaging plate) is used in a cassette.

FIG. 7 shows a perspective view of a panel according to a first embodiment of the present invention. A first non-planar surface delimiting the first gap 32 from the radiation 12 absorbing region 28b may be described by a function of the form z (x, y) = C x y x. In this embodiment, C> 0 is selected; however, C <0 can also be selected. A second non-planar surface, which is complementary to the first non-planar surface, delimits the first gap 32 from the radiation 12 absorbing region 28a.

The shutter of the present invention also includes additional gaps 32a and 32b defined by first and second additional non-planar surfaces, respectively, from the radiation absorbing regions 28a and 26, and 18 and 28b, respectively. It is, as in FIGS. 8 and 9 in more detail, each of the first additional non-planar surface is tilted relative to the first non-planar surface by an angle α about an axis parallel to the y-axis and rotated by an angle β about the z-axis, and the second additional not plane surface is in each case complementary to the first additional non-planar surface.

In this embodiment, the diaphragm has two additional gaps; however, as many additional columns as desired can be added to further enhance the imaging properties of the aperture. In this case, the spatial position of each further gap preferably results from the spatial position of the adjacent gap by the same isometry.

FIG. 8 shows a cross-sectional view of the aperture of FIG. 7 in sectional plane A in the direction of view a, with the first gap 32, the additional gaps 32a and 32b and the radiation-absorbing areas 18, 28a, 28b and 26. The additional column 32a and 32b are each tilted with respect to the first gap 32 by an angle α about an axis parallel to the y axis through the receiving unit 16 extending axis, so that the central rays of the column converge at the receiving unit 16. If the gaps are placed close to each other relative to the image plane, the angle α can be kept so small that distortions due to the oblique incidence on the image surface are negligible and the known approximations for small angles (sin α ≈ tan α) can be applied.

FIG. 9 shows a plan view of the central rays of the diaphragm of FIG. 7 in the direction b. The central beams 36a, 36b of the additional column are rotated relative to the central beam 36 of the first gap by an angle β about the z-axis. The superimposed floor plans serve only to clarify the alignment and do not relate to the visor body. The angle β can be chosen freely; it determines the distance or overlap of the adjacent partial images.

FIG. 10 shows a perspective view of the aperture of FIG. 7 with the first gap 32, the additional gaps 32a and 32b, the radiation absorbing areas 18, 28a, 28b and 26 and the central beam 36 of the first gap 32 and the central beams 36a and 36b of the additional gaps 32a and 32b. In the xy plane, all the beams from a passage direction open exactly onto a horizontal image axis 38, so that a sequence of the partial images caused by the gaps is ensured.

FIG. 11 shows a perspective view of a panel according to a second embodiment of the present invention. This diaphragm also has a first gap 32 and additional gaps 32a and 32b as well as the radiation 12 absorbing regions 18, 28a, 28b and 26. The first nonplanar surface delimiting the first gap 32 from the radiation 12 absorbing region 28b may in turn be described by a function of the form z (x, y) = C x y x. In this embodiment, C <0 is selected; however, C> 0 can also be selected.

The second embodiment of the present invention differs from the first embodiment in two essential features. On the one hand, the axis with respect to which the additional gaps are tilted by the angle α relative to the first gap coincides in this embodiment with the y-axis. As a result, no fixed distance is predetermined in this embodiment in which the receiving unit 16 must be arranged relative to the diaphragm.

On the other hand lies in this embodiment, the y-axis outside of the visor body. This is in FIG. 12 clarified in more detail.

FIG. 12 shows a perspective view to illustrate the structure of the aperture of FIG. 11 , For the sake of clarity, only the first gap 32 is shown. Except for the outline of the panel 100 'according to the second embodiment of the present invention, the outline of the panel 100 of the first embodiment is shown for comparison. Furthermore, in each case the lines of intersection of the first gap 32 with the outer boundary surfaces of the two diaphragms are shown. Aperture 100 'is truncated at x ₀ ≥ 0 at x coordinate x ₀ as compared to aperture 100; on the other hand, it is widened in the direction of higher x-coordinates compared to the stop 100. The beam guidance is unchanged from the first embodiment.

As a result of this asymmetrical design, the y-axis comes to lie outside the diaphragm body. This makes it possible to arrange the column tilted relative to each other about the y-axis, without causing the visor body falls apart. This makes it particularly easy to add more columns, and the individual columns can be made narrower. For example, to make a panel according to this second embodiment of the present invention, many columns could be realized by stacking correspondingly shaped panels with wedge-shaped profiles.

FIG. 13 Fig. 12 shows a z-direction plan view of a shear used in a third embodiment of the present invention. It is a shear in the y direction parallel to the yz plane. FIG. 13a shows the unsaved first gap, and FIG. 13b shows the sheared additional gap. In FIG. 13b Furthermore, the shear angle γ is plotted, which forms the sheared x- axis with the unsecured x- axis.

FIG. 14 shows a perspective view illustrating the construction of a diaphragm according to the third embodiment of the present invention. The first gap 32 and an additional, according to the in FIG. 13 Shear sheared gap 32a are shown. However, any number of additional columns can be added; Limits are set only by the mechanical stability of the visor material and by the need to maintain a sufficient thickness for the shielding layer. Due to the shear, the gaps do not interfere with each other in their course.

Except for the outline of the bezel 100 "according to the third embodiment of the present invention, for comparison, the outline of the bezel 100 of the first embodiment and the bezel 100 'of the second embodiment shown. Further, the cut lines of the first gap 32 with the contour of the visor 100 'are the lines of intersection of the additional gap 32a with the outline of the orifice 100 "and the shear angle γ shown the aperture 100". In comparison to the aperture 100' in the y - Extended direction, so that according to the in FIG. 14 Shear shear shown additional gap 32a finds place in it.

The larger the shear angle γ, the wider the overall image becomes. Since the intensity of the sub-images decreases sideways from the center of each slit, an overlap of the sub-images of the individual slits should be provided in the selection of the shear angle γ.

FIG. 15 is a perspective view of a panel according to a fourth embodiment of the present invention. Again, the first gap 32 and an additional gap 32a are shown, with further gaps being added. The bezel according to the fourth embodiment of the present invention consists of two bezels according to the third embodiment of the present invention, which are joined together at their central axes. As a result, a higher wall thickness for particularly high-energy radiation can be achieved.

LIST OF REFERENCE NUMBERS

100 ( ') ( ")

cover

200

Imaging device

10

Radiation source / Test object

12

(high energy) radiation / radiation field

14

Imaging area / projection

16

Receiver unit / detector / camera

18

Radiation absorbing area

20

first non-level surface

22a, b

Beam paths / radiation beam

24a, b

side edges

26

Radiation absorbing area

28a, b

Radiation absorbing areas

30

Shielding / shielding

32

(first) gap

32a, b

additional column

34

Through opening

36

first central ray

36a, b

additional central beams

38

image axis

46

X-ray tube

48

Lead wall with window

50

Light diffuser / aluminum plate

Claims (15)

Aperture (100), in particular for an imaging device (200), which is suitable for limiting, in particular high-energy, radiation (12) emanating from a radiation source (10) and onto an imaging region (14) along an optical axis x according to the hole-camera principle. to judge
wherein the diaphragm (100) comprises the radiation (12) at least partially absorbing regions (18, 28a, 28b, 26) and
wherein in the diaphragm (100) there is provided a first gap (32) or at least a first area which absorbs low radiation (12), which has at least one first non-planar surface and a second non-planar surface which separates it from the ones Delimiting radiation (12) at least partially absorbing regions (18, 28a, 28b, 26),
wherein the contour of the first non-planar surface at least partially by a function z ( x, y ) = f ( y ) * x + n ( y ) can be described and
wherein the contour of the second nonplanar surface is at least partially complementary to the contour of the first nonplanar surface,
characterized in that
there is at least one additional gap (32a, 32b) in the diaphragm (100) or at least at least one additional region which absorbs the radiation (12) to a small extent,
wherein each additional gap (32a, 32b) or the low-absorbing radiation (12) has at least a first additional non-planar surface and a second additional non-planar surface which isolates it from the radiation absorbing areas (12) (18, 28a, 28b, 26), and
wherein an associated affine image exists for each additional gap (32a, 32b) or the region (12) of low absorption (12),
wherein each of the contour of the first additional non-planar surface after application of the associated affine mapping at least partially by the function z (x, y) can be described and
wherein in each case the contour of the second additional non-planar surface is at least partially complementary to the contour of the first additional non-planar surface. Aperture (100) according to claim 1,
characterized in that
the set of affine mappings which can be sequenced by identity mapping as well as for each additional slit (32a, 32b) or radiation (12) low absorbing region of the associated affine image such that a sequence-generating affine map exists such that for each pair of affine maps that follow one another in the sequence, the affine image of the pair following in the sequence results from concatenation of the affine image of the pair preceding the sequence with the sequence-generating affine map. Aperture (100) according to claim 1 or 2,
characterized in that
for each additional gap (32a, 32b) or the radiation (12) low absorbing area the associated affine image is an isometry. Aperture (100) according to claim 3,
characterized in that
for each additional gap (32a, 32b) or the radiation-absorbing area (12), the isometry can be described in each case as concatenation of a first isometry and a second isometry,
wherein each of the first and second isometries is either a translation along a coordinate axis or a rotation about an axis parallel to a coordinate axis or coincident with a coordinate axis. Aperture (100) according to claim 4,
characterized in that
for each additional gap (32a, 32b) or the radiation (12) low absorbing area
the first isometry is in each case a rotation about a respective angle α about a first axis which lies in the x - y plane and runs parallel to the y axis or coincides with the y axis and
the second isometry is in each case a rotation about a respective angle β about a second axis which lies in the x - z plane and runs parallel to the z axis or coincides with the z axis. Aperture (100) according to claim 5,
characterized in that
for each additional gap (32a, 32b) or the radiation (12) low absorbing area, the second axis coincides with the z-axis and / or the first axis coincides with the y- axis and / or the angle β in each case 0 ° is. Aperture (100) according to claim 1 or 2,
characterized in that
for each additional slit (32a, 32b) or radiation (12), the associated affine image is a shear in y- direction parallel to the y - z plane. Aperture (100) according to one of the preceding claims,
characterized in that
the function z (x, y) has the form z ( x, y ) = A * x + B * y + C * y * x + n . An orifice (100) according to claims 6, 7 and 8,
characterized in that
for each additional slit (32a, 32b) or radiation (12) low absorbing area, the respective angles α and β are each linked by the equation α = B * β. Shutter (100) according to one of claims 8 or 9,
characterized in that
the constant A has the value 0 and / or the constant B has the value 0. Aperture (100) according to one of the preceding claims,
characterized in that
the regions (18, 28a, 28b, 26) which at least partially absorb the radiation (12) are arranged in a region with x > x ₀ , where x _{0 is} a constant value with x ₀ ≥ 0. A method of making a panel (100) according to any one of the preceding claims, in which a relative movement between a cutting tool capable of cutting along a straight line and a workpiece is carried out such that the cutting tool cuts the workpiece along a line which corresponds to a beam path in the diaphragm (100) to be produced,
characterized in that
the relative movement is repeated at least once,
wherein before each repetition of the relative movement, the workpiece is moved. A method according to claim 12, characterized in that the workpiece is cut along a fixed first direction (x). A method according to claim 13, characterized in that a rotational movement of the workpiece about a first axis of rotation which is along a second direction (z) perpendicular to the cutting direction (x) of the cutting tool, and at the same time a translational movement of the workpiece along the second direction (z) become. A method according to claim 14, characterized in that the rotational movement and the translational movement of the workpiece are linearly coupled.

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