A multi-leaf grating

Abstract

The embodiment of the present invention discloses a multi-leaf grating, which includes: 2*2 blade groups, the upper blade group and the lower blade group are correspondingly arranged, the blade group includes m*n grating blades, the row direction and the column direction of the matrix are parallel to the surface of the grating blades and perpendicular to the arrangement direction of the grating blades in the blade group, the lower end surface of the grating blades in the upper blade group facing the lower blade group is provided with a code disk structure, and the upper end surface of the grating blades in the lower blade group facing the upper blade group is provided with a code disk structure; two position detection devices are located outside the two sides of the 2*2 blade group along the row direction, the position detection device includes a bracket, a circuit board arranged on the bracket, and two code reader groups electrically connected to the circuit board, the circuit board is located in the gap between an adjacent group of upper blade groups and a lower blade group, and the code reader sequentially reads the positions of the n adjacent grating blades corresponding thereto. The present invention reduces the physical space size of the multi-leaf grating.

Description

Technical Field

[0001] The embodiments of the present invention relate to grating technology, and in particular to a multi-leaf grating. Background Art

[0002] Multileaf grating is an important component of radiotherapy equipment and is mostly used in dynamic treatment. Dynamic intensity modulated radiotherapy technology (including IMRT\VMAT, etc.) has obvious advantages over static intensity modulated radiotherapy technology. It can improve the dose distribution level in the patient's body, effectively reduce the radiation dose to important organs and healthy tissues, and thus improve the quality of treatment.

[0003] In the dynamic intensity modulated radiotherapy equipment, the position detection of each grating blade in the multi-leaf grating includes at least two sets of independent position detection devices. One set is a position detection device driven by a DC permanent magnet motor, and the motor tail of the position detection device is integrated with an encoder, and the other set is a position detection device based on a conductive plastic resistor. Both sets of position detection devices are located on the periphery of the grating blades, occupying more space, resulting in a larger overall size of the multi-leaf grating. In addition, a large amount of stray scattered rays in the working environment of the multi-leaf grating will also seriously affect the life of the electronic components in the position detection device, reducing the service life of the multi-leaf grating. Summary of the invention

[0004] The embodiment of the present invention provides a multi-leaf grating to reduce the physical space size of the multi-leaf grating.

[0005] An embodiment of the present invention provides a multi-leaf grating, comprising:

[0006] 2*2 blade groups are arranged in a matrix, an upper blade group located in the first row and a lower blade group located in the second row of the 2*2 blade groups are arranged correspondingly, the blade group comprises m*n grating blades arranged in a stacked manner, the row direction and the column direction of the matrix are both parallel to the surface of the grating blades and are both perpendicular to the arrangement direction of the grating blades in the blade group, a code disk structure is provided on the lower end surface of the grating blades in the upper blade group facing the lower blade group, and a code disk structure is provided on the upper end surface of the grating blades in the lower blade group facing the upper blade group;

[0007] Two position detection devices are located outside the two sides of the 2*2 blade groups along the row direction, the position detection devices include a bracket, a circuit board arranged on the bracket, and two code reader groups electrically connected to the circuit board, the circuit board is located in the gap between an adjacent group of the upper blade group and the lower blade group, one code reader group is arranged corresponding to one blade group, the code reader group includes m code readers, one code reader is arranged corresponding to n adjacent grating blades in the blade group corresponding to it, and the code reader is used to sequentially read the positions of the n adjacent grating blades corresponding to it.

[0008] The multi-leaf grating provided in the embodiment of the present invention is a double-layer multi-leaf grating, wherein the lower end surface of the grating blades in the upper blade group facing the lower blade group is provided with a code disk structure, and the upper end surface of the grating blades in the lower blade group facing the upper blade group is provided with a code disk structure; the circuit board in the position detection device is located in the gap between an adjacent group of upper blade groups and lower blade groups, and the code reader arranged on the circuit board can read the position of each grating blade corresponding to it in a blade group it faces. Compared with the prior art, the main body of the position detection device in the embodiment of the present invention is arranged within the interlayer spacing of the double-layer multi-leaf grating, does not occupy the physical space of the multi-leaf grating additionally, reduces the physical space size of the multi-leaf grating, and can detect the position of the grating blades in real time; the position detection device can detect the absolute position of each grating blade, and the detection accuracy is higher; in addition, the position detection device is arranged between the upper blades and the lower blades, and can also make full use of the shielding effect of the upper grating blades and the lower grating blades on scattered rays, reduce the damage of scattered rays to electronic components in the position detection device, and improve the service life of the position detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, although the drawings described below are some specific embodiments of the present invention, for those skilled in the art, the basic concepts of the device structure, driving method and manufacturing method disclosed and suggested by the various embodiments of the present invention can be expanded and extended to other structures and drawings, and there is no doubt that these should be within the scope of the claims of the present invention.

[0010] Figure 1 is a schematic diagram of a multi-leaf grating provided by an embodiment of the present invention;

[0011] Figure 2 is a schematic diagram of the end face of the grating blade of the blade group;

[0012] Figure 3 It is a three-dimensional schematic diagram of the blade group;

[0013] Figure 4 is a three-dimensional schematic diagram of the grating blade;

[0014] Figure 5 is a three-dimensional schematic diagram of a position detection device;

[0015] Figure 6 It is a schematic diagram of the structure of the code reader;

[0016] Figure 7 It is a schematic diagram of the structure of the grating blade and its corresponding code reader;

[0017] Figure 8It is a schematic diagram of the structure of the code reader group;

[0018] Fig. 9 It is a schematic diagram of the structure of the code reader group;

[0019] Fig.10 It is a structural schematic diagram of a blade group and its corresponding code reader group;

[0020] Fig.11 is a three-dimensional schematic diagram of a shielding device;

[0021] Fig.12 is a schematic diagram of the relative positions of the blade assembly and the shielding device;

[0022] Fig.13 is a three-dimensional schematic diagram of a shielding device;

[0023] Fig.14 It is a schematic diagram of the structure of the blade group and the heat dissipation device;

[0024] Fig.15 is a schematic diagram of a heat sink;

[0025] Fig.16 This is the overall structure diagram of the multi-leaf grating. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described through implementation methods with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the basic concepts disclosed and suggested by the embodiments of the present invention, all other embodiments obtained by those skilled in the art are within the scope of protection of the present invention.

[0027] refer to Figure 1 As shown, it is a schematic diagram of a multi-leaf grating provided by an embodiment of the present invention, such as Figure 2 The figure shows the end face of the grating blade of the blade group. Figure 3 The three-dimensional schematic diagram of the blade group is shown in FIG. Figure 4The figure shows a three-dimensional schematic diagram of a grating blade. The multi-leaf grating provided in this embodiment may be a double-layer multi-leaf grating, which comprises: 2*2 blade groups 10 arranged in a matrix, wherein the upper blade group 10a located in the first row and the lower blade group 10b located in the second row of the 2*2 blade groups 10 are arranged correspondingly, the blade group 10 comprises m*n grating blades 11 arranged in a stacked manner, the row direction X and the column direction Y of the matrix are both parallel to the surface of the grating blades 11 and are both perpendicular to the arrangement direction Z of the grating blades 11 in the blade group 10, the lower end surface of the grating blades 11 in the upper blade group 10a facing the lower blade group 10b is provided with a code disk structure 12, and the upper end surface of the grating blades 11 in the lower blade group 10b facing the upper blade group 10a is provided with a code disk structure 12; 2 position detection devices 20, located outside the 2*2 blade groups 10 on both sides along the row direction X, the position detection device 20 includes a bracket 21, a circuit board 22 arranged on the bracket 21 and two code reader groups 23 electrically connected to the circuit board 22, the circuit board 22 is located in the gap between an adjacent group of upper blade groups 10a and lower blade groups 10b, one code reader group 23 is arranged corresponding to one blade group 10, the code reader group 23 includes m code readers, one code reader in the code reader group 23 is arranged corresponding to n adjacent grating blades 11 in the blade group 10 corresponding to it, the code reader is used to read the positions of the n adjacent grating blades 11 corresponding to it in sequence, and n is a positive integer.

[0028] In this embodiment, the multi-leaf grating includes four blade groups 10 and the four blade groups 10 are distributed in an upper and lower double-layer structure, which are two upper blade groups 10a located in the first row and two lower blade groups 10b located in the second row, and one upper blade group 10a and one lower blade group 10b are arranged correspondingly. The surface of the grating blades 11 in the blade group 10 is located in the XY plane, and the total number of grating blades 11 in the blade group 10 is m*n pieces, and the m*n pieces of grating blades 11 are stacked and arranged along the Z direction, and the arrangement direction Z of the grating blades 11 is perpendicular to the XY plane. In the matrix of 2*2 blade groups 10, the row direction X is parallel to the surface of the grating blades 11, that is, the XY plane, and in the matrix of 2*2 blade groups 10, the column direction Y is parallel to the XY plane. Figure 1 The surface of the grating blade 11 is shown as Figure 2 The end surface, ie, the side surface, of the grating blade 11 in the blade assembly 10 is shown. The end surface of the grating blade 11 is perpendicular to the surface of the grating blade 11 .

[0029] Combination Figure 2 to Figure 4As shown, a code disk structure 12 is provided on the upper end surface or the lower end surface of the grating blade 11 of the multi-leaf grating. The code disk structure 12 refers to a visible (for detection) coding structure formed on the end surface of the grating blade 11 by a physical method. The coding method of the code disk structure 12 can adopt one-dimensional coding, two-dimensional coding or any coding method, and the coding process can adopt laser engraving, mechanical engraving and other processes. For the upper blade group 10a, the lower end surface of the grating blade 11 facing the lower blade group 10b is provided with a code disk structure 12, and for the lower blade group 10b, the upper end surface of the grating blade 11 facing the upper blade group 10a is provided with a code disk structure 12, that is, the opposite end surfaces of the upper blade group 10a and the lower blade group 10b are both provided with a code disk structure 12.

[0030] The optional encoding method is as follows: first, establish the initial matrix A[i] of the i-th encoding position, the order of the initial matrix A[i] is M*N and each matrix element is a binary number, the right submatrix CR composed of the elements from the 2nd to the Nth columns in A[i] is the same as the left submatrix CL composed of the elements from the 1st to the N-1th columns in A[i+1]; then form the encoding matrix of the code disk, which is composed of the initial matrix A[1] of the first encoding position and the last column submatrix C[2],…,C[j],…,C[2 M*N ] are sequentially concatenated to form the last column submatrix C[j], which is the submatrix formed by the Nth column elements in A[j]. The coding matrix is ​​the code actually formed on the code disk. Obviously, in this embodiment, the number of coding rows on the M*N bit code disk is M rows, and the number of columns is N-1+2 M*N The existing M*N encoders with the same range have M*N rows and 2 columns on the code disk. M*N Compared with the prior art, the new encoding method makes the physical space width of the M*N-bit code disk approximately 1 / N of the existing one under the same measurement accuracy. Therefore, the physical space size of the code disk is effectively reduced under the same range, or a larger range can be achieved under the same physical space size.

[0031] In this embodiment, the two position detection devices 20 are respectively located outside the two sides of the blade group 10 along the row direction X. Specifically, as shown in FIG. Figure 1The 2*2 blade groups 10 shown have two opposite sides (left and right sides in the figure) in the row direction X, wherein one position detection device 20 is located on the left side of the blade group 10 shown in the figure, and the other position detection device 20 is located on the right side of the blade group 10 shown in the figure. The position detection device 20 includes a bracket 21 and a circuit board 22 arranged on the bracket 21, wherein the optional bracket 21 includes a transverse support plate and two longitudinal support plates fixed at both ends of the transverse support plate, and the circuit board 22 can be fixed on the transverse support plate, and the extension direction of the transverse support plate of the circuit board 22 is parallel to the Z direction. The circuit board 22 is located in the gap between a group of upper blade groups 10a and lower blade groups 10b adjacent thereto, so that the position detection device 20 makes full use of the gap between the adjacent upper and lower blade groups 10 for setting, and does not occupy additional space of the multi-leaf grating in the matrix column direction Y.

[0032] The position detection device 20 also includes two code reader groups 23 electrically connected to the circuit board 22. One position detection device 20 is located between the upper and lower blade groups 10 and is used to detect the positions of the blades in the upper and lower blade groups 10. The multi-leaf grating includes four blade groups 10, and one blade group 10 is corresponding to one code reader group 23. Specifically, one position detection device 20 corresponds to two blade groups 10, and then one code reader group 23 on the circuit board 22 is used to read the positions of each blade in the adjacent upper blade group 10a, and the remaining code reader group 23 is used to read the positions of each blade in the adjacent lower blade group 10b. In one code reader group 23, one code reader can be used to read the position of at least one grating blade 11 in a blade group 10 corresponding to it.

[0033] A code reader in the optional code reader group 23 is set corresponding to a grating blade 11 in the blade group 10, and the code reader is only used to read the position of the corresponding grating blade 11. Then, in the position detection stage, the code reader reads the position code of the code disk structure of the corresponding grating blade, and the circuit board determines the position of each grating blade according to the position code information output by each code reader.

[0034] The optional code reader group 23 includes m code readers, and a blade group 10 includes m*n grating blades 11. Then, one code reader in the code reader group 23 is set corresponding to n adjacent grating blades 11 in the blade group 10, and the code reader reads the positions of the corresponding n adjacent grating blades 11 in time sharing. In the position detection stage, the circuit board moves to the first code reading position, the code reader reads the position code of the code disk structure of the first grating blade that is currently facing the only front side, and the circuit board determines each grating blade read and its position information according to the first code reading position and the position code information output by each code reader; sequentially, the circuit board moves to the second code reading position, the code reader reads the position code of the code disk structure of the second grating blade that is currently facing the only front side, and the circuit board determines each grating blade read and its position information according to the second code reading position and the position code information output by each code reader; sequentially, the circuit board moves to the nth code reading position, the code reader reads the position code of the code disk structure of the nth grating blade that is currently facing the only front side, and the circuit board determines each grating blade read and its position information according to the nth code reading position and the position code information output by each code reader. By moving the circuit board to n different target code reading positions, the code reader can read the position code of the code disk structure of the n grating blades corresponding to it in time division and perform position analysis, and obtain the position information of the n grating blades corresponding to each code reader. Based on this, the position detection device 20 can detect the absolute position of each grating blade 11 with higher detection accuracy.

[0035] The number of grating blades 11 in the optional blade group 10 is a multiple of the number of code readers in a code reader group 23, so that the number of grating blades corresponding to each code reader is equal, which is convenient for the setting and layout of the position detection device 20. For example, the blade group includes 30 grating blades, and the code reader group includes 3 code readers. In the position detection stage, one code reader needs to read the positions of the 10 grating blades corresponding to it in time-sharing.

[0036] The code reader group 23 is arranged on the circuit board 22, and each code reader group 23 faces the code disc structure 12 of the lower end surface of the upper blade group 10a or the code disc structure 12 of the upper end surface of the lower blade group 10b. The code reader in the code reader group 23 can only read the position of one grating blade 11 facing it at a time, so that the reading is unique. The code reader can read the positions of multiple grating blades 11 through multiple displacements in the position detection stage. Figure 4 A single reading area 13 of a grating blade 11 read by a code reader is shown. After each displacement, the code reader can read a position code with a single reading length of the code disk structure in the grating blade. The relative displacement of the grating blade and the code reader can be obtained by parsing the position code, thereby determining the position of the grating blade.

[0037] The multi-leaf grating provided in the embodiment of the present invention is a double-layer multi-leaf grating, wherein the lower end surface of the grating blades in the upper blade group facing the lower blade group is provided with a code disk structure, and the upper end surface of the grating blades in the lower blade group facing the upper blade group is provided with a code disk structure; the circuit board in the position detection device is located in the gap between the upper blade group and the lower blade group of the nearest neighbor, and the code reader arranged on the circuit board can read the position of each grating blade corresponding to it in the blade group it faces. Compared with the prior art, the main body of the position detection device in the embodiment of the present invention is arranged within the interlayer spacing of the double-layer multi-leaf grating, does not occupy the physical space of the multi-leaf grating additionally, reduces the physical space size of the multi-leaf grating, and can detect the position of the grating blades in real time; the position detection device can detect the absolute position of each grating blade, and the detection accuracy is higher; in addition, the position detection device is arranged between the upper blades and the lower blades, and can also make full use of the shielding effect of the upper grating blades and the lower grating blades on the scattered rays, reduce the damage of the scattered rays to the electronic components in the position detection device, and improve the service life of the position detection device.

[0038] Exemplarily, based on the above technical solution, Figure 5 The optional two code reader groups 23 shown include one code reader group 23a located on the surface of the circuit board 22 facing the upward blade group and one code reader group (not shown) located on the surface of the circuit board 22 facing the downward blade group. Each code reader group 23 includes a plurality of code readers 23a arranged along the arrangement direction Z of the grating blades, and the Z direction is perpendicular to the surface of the grating blades.

[0039] It is known that the multi-leaf grating is a double-layer structure, and the lower end surface of the grating blades in the upper blade group and the upper end surface of the grating blades in the lower blade group are both provided with a code disk structure, so the code reader 23a should be divided into a code reader for reading the code disk structure of the grating blades in the upper blade group and a code reader for reading the code disk structure of the grating blades in the lower blade group. The circuit board 22 is located in the gap between the upper blade group and the lower blade group, and the code reader 23a is located on the circuit board 22, then a code reader group 23 can be provided on one side surface of the circuit board 22 facing the corresponding upper blade group to read the position of each grating blade in the corresponding upper blade group; a code reader group 23 can be provided on one side surface of the circuit board 22 facing the corresponding lower blade group to read the position of each grating blade in the corresponding lower blade group. It can be understood that the multiple code readers 23a in the code reader group 23 are arranged along the Z direction, which is parallel to the arrangement direction of the grating blades in the blade group. The code reader 23a faces the code disk structure of the n grating blades to be read, so as to directly read the position of each grating blade corresponding to it.

[0040] like Figure 5The optional position detection device 20 shown also includes: a guide rail 24 and a grating ruler 25 fixed on the bracket 21, the guide rail 24 and the grating ruler 25 are arranged in parallel and extend along the arrangement direction of the grating blades; a mechanical connection component 26 is arranged on the guide rail 24, the end of the mechanical connection component 26 close to the grating ruler 25 is fixedly connected to the grating head 27, the end of the mechanical connection component 26 away from the grating ruler 25 is fixedly connected to the circuit board 22, and the mechanical connection component 26 moves on the guide rail 24 to drive the circuit board 22 and the grating head 25 to move synchronously. Optional n is greater than 1.

[0041] The thickness of the grating blades is relatively thin, mostly several millimeters. The number of grating blades in a blade group is about dozens and the blades are closely connected to each other. Therefore, the thickness of the blade group in the Z direction is relatively small. Compared with the thickness of the grating blades, the width of the code reader is much larger than the total thickness of multiple grating blades. If an independent code reader is set above the code disk structure of each grating blade, the physical space cannot meet the demand or the occupied physical space is too large, which increases the volume of the multi-leaf grating. Based on this, in this embodiment, one blade group is set to correspond to one code reader group 23, and one code reader group 23 includes m code readers 23a. One code reader 23a is set corresponding to n grating blades in one blade group, and n is greater than 1.

[0042] It is known that in a position detection phase, the code reader 23a can only read the position code of one grating blade at a time. One code reader 23a is set corresponding to at least two grating blades. In the position detection phase, the code reader 23a needs to read the position codes of n grating blades in n times in order to accurately obtain the position information of each grating blade. Based on this, a displacement control module is provided in the position detection device 20, which is specifically composed of a guide rail 24 and a mechanical connection component 26. The mechanical connection component 26 is displaced on the guide rail 24, which can drive the grating head 27 and the circuit board 22 to move synchronously.

[0043] The grating head 27 and the grating ruler 25 are used to locate the code reading position of the circuit board 22. Specifically, after the circuit board 22 moves, the grating head 27 moves relative to the grating ruler 25, and the grating ruler 25 can determine the specific position of the grating head 27 and then determine whether the circuit board 22 has moved to the target code reading position. The circuit board 22 should have n target code reading positions. The grating ruler 25 detects the position of the grating head 27 and determines that it has reached the target code reading position. Then the code reader 23a faces one of the n grating blades corresponding to it, and can read the position code of the grating blade. When the circuit board 22 moves to other target code reading positions again, the code reader 23a reads the position code of another grating blade corresponding to it again. By analogy, the circuit board 22 moves to n target code positions respectively, and the code reader 23a reads the position codes of the n grating blades corresponding to it in a time-sharing manner and performs position analysis.

[0044] It can be understood that the target code reading position of the circuit board 22 is associated with multiple grating blades in the corresponding two blade groups. For example, when the circuit board 22 is located at the first code reading position, each code reader corresponds to the first grating blade among its n grating blades, and the code reader reads the position code of the first grating blade and obtains its position information. The circuit board 22 can determine the corresponding first grating blade and the position of the grating blade based on the target code reading position and the position code information transmitted by the code reader 23a.

[0045] By setting the barcode readers on the upper and lower surfaces of the circuit board, the physical space of a barcode reader group is expanded, and the number of barcode readers in a barcode reader group can be increased to improve the detection efficiency. The barcode reader corresponds to n grating blades, and reads the positions of the corresponding n grating blades n times in time, which can avoid the barcode reader occupying too much physical space.

[0046] The spacing between two code readers that are arranged adjacently on the same layer can be equal to the sum of the thicknesses of at least two grating blades. The code readers 23a are evenly arranged on the circuit board 22 along the Z direction, and there is a gap between adjacent code readers 23a, and the gap is equal to a multiple of the thickness of the grating blade. Then, the movement variable of the circuit board 22 is based on the thickness of the grating blade, so that at each target code reading position, the code reader 23a can be located directly above the grating blade to be read, and will not deviate to cause a reading error.

[0047] like Figure 6 The optional code reader 23a shown includes an image acquisition module 231 and an optical path module; the image acquisition module 231 is mounted on a circuit board; the optical path module includes a support unit 232 and an imaging lens 233, an illumination light source and an illumination condenser lens 234 mounted on the support unit 232; the support unit 232 is mounted on the circuit board and straddles the image acquisition module 231. The image acquisition module 231 includes a planar array photosensitive unit 235 and a data processing unit (not shown). In the position detection stage, the illumination light source (not shown) located in the support unit 232 emits light, and its light is transmitted through the illumination condenser lens 234 and incident on the code disk structure of the grating blade opposite to the front. The light reflected by the code disk structure enters the imaging lens 233 and propagates to the planar array photosensitive unit 235 of the image acquisition module 231 for photosensitive imaging, thereby obtaining the position coding information of the measured grating blade. The circuit board determines the measured grating blade and its corresponding position information based on the imaging information. The optional illumination light source is a white light LED or other types of light-emitting elements. In this embodiment, the cost of structures such as the image acquisition module, the imaging lens, and the illumination light source is low, and the cost of the multi-leaf grating will not be greatly increased.

[0048] The support unit 232 is installed on the circuit board 22, and its two support bases cross the image acquisition module 231. This design can save the installation size of the code reader 23a, thereby reducing the overall size of the position detection device.

[0049] Exemplarily, based on the above technical solution, an optional code reader corresponds to a grating blade in a blade group, and the code reader is used to read the position of a grating blade corresponding thereto. In this embodiment, each grating blade has a corresponding code reader, and the code reader reads the position of the unique corresponding grating blade, so the circuit board does not need to be moved. In the position detection stage, each code reader only needs to read the position code of the unique corresponding grating blade once, and the circuit board can obtain the position information of all grating blades without multiple readings, which effectively improves the detection efficiency.

[0050] like Figure 7 The optional code reader shown includes an image acquisition module 236 and an optical path module; the optical path module includes an optical fiber bundle 237, a lens support frame 238 and an imaging lens 239 arranged in the lens support frame 238, the extension direction of the optical fiber bundle 237 is the same as the extension direction X of the grating blade 11, the front end of the optical fiber bundle 237 faces the code disk structure 12 of the grating blade 11 corresponding to it, and the rear end of the optical fiber bundle 237 faces the imaging lens 239; the image acquisition module 236 is installed directly above the lens support frame 238, and the image acquisition module 236 or the lens support frame 238 is directly installed on the circuit board.

[0051] In this embodiment, during the position detection stage, the light reflected by the code disk structure 12 enters the front end of the optical fiber bundle 237 and propagates therein so that the light is output from the rear end of the optical fiber bundle 237. The light enters the imaging lens 239 and propagates to the image acquisition module 236 for photosensitive imaging, thereby obtaining the position coding information of the measured grating blade. The circuit board determines the position information of the measured grating blade according to the imaging information.

[0052] It is known that the size of the code reader is much larger than the thickness of the grating blade 11. Based on the flexibility or bendability of the optical fiber bundle 237, a code reader group corresponding to a blade group can be set as a multi-layer structure along the Y direction or the X direction. The code readers corresponding to two adjacent grating blades in a blade group are located in different layers, for example Figure 8 The code reader group shown includes multiple layers of code readers arranged along the extension direction X of the grating blades, or, as shown in FIG. Fig. 9The code reader group shown includes multiple layers of code readers arranged along the Y direction. As shown in the figure, by expanding the size of the code reader group in the Y direction or the X direction, the size of the code reader group in the Z direction can be reduced so that it can be accommodated in the gap between the upper and lower leaf groups. On the basis of improving the detection efficiency, the size of the code reader group is effectively controlled without significantly increasing the physical space of the multi-leaf grating.

[0053] like Fig.10 The optional position detection device shown also includes: a strip lighting module 240, the extension direction of the lighting module 240 is parallel to the arrangement direction of the grating blades 11, and the strip lighting module 240 is placed at the front end of the optical fiber bundle 237 to provide lighting for the code disk structure of each grating blade 11 in a blade group. The optional lighting module 240 is composed of a plurality of light emitting diodes (LEDs). The light emitted by the strip lighting module 240 is incident on the code disk structure of each grating blade 11 in the blade group, and the light reflected by the code disk structure 12 enters the front end of the optical fiber bundle 237 and propagates therein so that the light is output from the rear end of the optical fiber bundle 237, and the light enters the imaging lens 239 and propagates to the image acquisition module 236 for photosensitive imaging, thereby obtaining the position coding information of the grating blade to be measured.

[0054] The position detection device provided in this embodiment can produce a code reader that is set in one-to-one correspondence with the grating blades within the limited spacing space between the upper and lower blade groups of the multi-leaf grating. During the position detection stage, each code reader only needs to read the position code of the uniquely corresponding grating component once to realize the position detection of the grating blades. The absolute position of each grating blade can be detected, thereby improving the detection efficiency and detection accuracy, and further improving the response speed of the multi-leaf grating system.

[0055] Exemplarily, based on the above technical solution, Fig.11 and Fig.12 The optional grating blade 11 shown has a through slot 11b for accommodating the grating screw rod 11a; the multi-leaf grating also includes: two shielding devices 30, which are respectively located outside the two sides of the 2*2 blade groups 10 along the row direction X, and the shielding device 30 includes a shielding plate 31 and a plurality of couplings 32. The shielding plate 31 has a plurality of through holes 31a, and the through holes 31a are divided into a front hole portion facing the grating blade 11 and a rear hole portion away from the grating blade 11. The aperture of the front hole portion is smaller than the aperture of the rear hole portion. A coupling The coupling 32 is arranged corresponding to a through hole 31a and assembled in the rear hole portion of the corresponding through hole 31a, and a grating motor 40 is assembled on a coupling 32; a grating screw rod 11a is arranged corresponding to a through hole 31a and one end of the grating screw rod 11a is assembled in the front hole portion of the corresponding through hole 31a, and the other end of the grating screw rod 11a is accommodated in the through slot 11b of the corresponding grating blade 11, and the grating motor 40 drives the corresponding grating blade 11 through the coupling 32 and the grating screw rod 11a in turn. Among them, Fig.11is a three-dimensional schematic diagram of the shielding device. Fig.12 It is a schematic diagram of the relative positions of the blade group and the shielding device.

[0056] Each grating blade of the multi-leaf grating has a through slot for accommodating a grating lead screw. When the accelerator in the multi-leaf grating is working, the radiation generated by the accelerator will leak out from the through slot. This part of the radiation irradiates the encoder of the grating motor and affects the life of the encoder. In this embodiment, a shielding device 30 is provided on the outside of the through slot 11b of the blade group 10, which can shield or block the radiation leaking from the through slot 11b of the grating blade 11, which can greatly reduce the radiation irradiated on the grating motor 40, and correspondingly can protect the electronic components in the grating motor 40, thereby increasing the service life of the grating motor 40.

[0057] The optional shielding plate 31 is made of radiation shielding material, and its geometric shape can be a cuboid, and a plurality of through holes 31a are processed on the surface of the cuboid. The through holes 31a are divided into a front through hole close to the grating blades 11 and a rear through hole away from the grating blades 11, and the aperture of the front through hole is smaller than the aperture of the rear through hole. The optional shielding plate 31 also has the function of fixing the grating motor 40. Specifically, the coupling 32 is made of radiation shielding material, and is mainly composed of two truncated cones with different diameters, and the diameter of the truncated cone is slightly smaller than the diameter of the corresponding through hole 31a. When the multi-leaf grating is matched, each coupling 32 is assembled in the corresponding through hole 31a of the shielding plate 31.

[0058] like Fig.13 The optional shielding device 30 further includes a shielding shell 33, which has a plurality of openings, one coupling 32 being arranged corresponding to one opening, and the grating motor assembled on the coupling 31 being accommodated in the corresponding opening. The shielding shell 33 can protect the grating motor while achieving a shielding effect.

[0059] In this embodiment, by providing a shielding device on the outside of the blade group, based on the special design of the shielding plate and the coupling, the leaked rays can be effectively shielded, the failure rate of electronic components in the grating motor can be reduced, and no additional space will be occupied.

[0060] Exemplarily, based on the above technical solution, Fig.14 and Fig.15The optional multi-leaf grating shown also includes: a heat dissipation device 50, the heat dissipation device 50 includes a water tank 52 and at least one radiator 53 connected by a circulation pipe 51; the water tank 52 is located on the outside of the blade group 10 along the row direction X, and the radiator 53 is located on the outside of the blade group 10 along the grating blade arrangement direction Z; the water tank 52 is a cavity structure, liquid is stored in the cavity and the cavity has a plurality of hollow holes 52a passing through the cavity, a grating motor 40 for driving the grating blades is arranged corresponding to a hollow hole 52a and assembled in the hollow hole 52a; the radiator 53 includes a box body and a fan located above the box body, the box body is used to store liquid and exchange liquid with the water tank 52, and the fan cools the liquid in the box body.

[0061] When the motor is working, part of its energy will be converted into heat. If this part of heat cannot be dissipated in time, it will affect the life and performance of the motor. For the multi-leaf grating, its own structural limitations make dozens of grating motors closely arranged together, and the heat dissipation condition is poor. In this embodiment, a heat dissipation device is added to effectively dissipate the heat of the grating motor, ensuring the normal operation and service life of the multi-leaf grating.

[0062] In this embodiment, the optional water tank 52 has a rectangular shape and is a cavity-enclosed structure. Liquid such as coolant or water is stored in the water tank 52. The front and rear surfaces of the water tank 52 are provided with through holes, i.e., hollow holes 52a. The shape of the hollow holes 52a is the same as that of the grating motor 40, such as both are cylindrical. The size of the hollow holes 52a is similar to the cross-sectional size of the grating motor 40, so that the grating motor 40 can be accommodated in the hollow holes 52a. One hollow hole 52a is arranged corresponding to one grating motor 40, and one grating motor 40 is arranged corresponding to one grating blade. The liquid contained in the water tank 52 can achieve heat exchange with the grating motor 40. During the heat exchange, the heat of the grating motor 40 increases the temperature of the liquid in the water tank 52, and the heated liquid in the water tank 52 enters the radiator 53 through the circulation pipe 51. The outer shell of the optional water tank 52 is made of heat-conducting material to further improve the heat exchange efficiency.

[0063] The radiator 53 is connected to the water tank 52 through a circulation pipe 51, wherein the circulation pipe 51 includes a water inlet pipe and a water delivery pipe on the radiator 53 side, and the radiator 53 is a device for completing the heat exchange between liquid and gas. Specifically, the structure of the radiator 53 includes a lower box and an upper fan, the box is used to store liquids such as water or coolant, and the upper cover plate of the box has ventilation holes, the steam generated by the water in the box flows out through the ventilation holes of the cover plate, and the fan diffuses the outflowing gas into the air, and at the same time, the fan generates wind to input cold air into the box through air convection to reduce the water temperature in the box. The liquid in the radiator 53 is exchanged in real time with the liquid in the water tank 52, the liquid in the radiator 53 that has been cooled enters the water tank 52 to reduce the temperature of the liquid in the water tank 52, and the liquid in the water tank 52 that has been cooled enters the radiator 53 to cool down after heat exchange, and the heat dissipation of the grating motor 40 is achieved through the flow of liquid, thereby improving the heat dissipation efficiency of the grating motor 40. The optional radiator 53 adopts a fin radiator or a plate radiator. The optional multileaf collimator comprises at least two heat sinks 53 .

[0064] In this embodiment, the radiator 53 is located outside the arrangement direction of the grating blades of the blade group, and the water tank 52 is located outside the extension direction of the grating blades of the blade group. While achieving a good heat dissipation effect on the grating motor, it does not occupy too much physical space of the multi-leaf grating, making the structure of the multi-leaf grating compact and the overall space size not too large.

[0065] Based on the multi-leaf grating described in any of the above embodiments, Fig.16 The figure shows the overall structure of the multi-leaf grating, including a position detection device, and optionally at least one of a shielding device and a heat dissipation device. The position detection device can detect the absolute position of each grating blade with high detection accuracy; the shielding device can shield a large amount of stray scattered rays in the environment where the multi-leaf grating is located to protect the position detection device, and the heat dissipation device can dissipate heat from the drive motor of the grating blade. In addition, the multiple devices integrated in the multi-leaf grating are compactly arranged on the periphery of the grating blades, which does not occupy additional physical space, and the structure of each device is simple and low-cost.

[0066] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A multi-leaf grating, characterized in that: include: 2*2 blade groups are arranged in a matrix, an upper blade group located in the first row and a lower blade group located in the second row of the 2*2 blade groups are arranged correspondingly, the blade group comprises m*n grating blades arranged in a stacked manner, the row direction and the column direction of the matrix are both parallel to the surface of the grating blades and are both perpendicular to the arrangement direction of the grating blades in the blade group, a code disk structure is provided on the lower end surface of the grating blades in the upper blade group facing the lower blade group, and a code disk structure is provided on the upper end surface of the grating blades in the lower blade group facing the upper blade group; 2 position detection devices, located outside the two sides of the 2*2 blade groups along the row direction, the position detection devices include a bracket, a circuit board arranged on the bracket, and two code reader groups electrically connected to the circuit board, the circuit board is located in a gap between an adjacent group of the upper blade group and the lower blade group, one code reader group is arranged corresponding to one blade group, the code reader group includes m code readers, one code reader is arranged corresponding to n adjacent grating blades in the blade group corresponding to it, and the code reader is used to sequentially read the positions of the n adjacent grating blades corresponding to it; The two code reader groups include one code reader group located on the surface of the circuit board facing the upper blade group and one code reader group located on the surface of the circuit board facing the lower blade group, and each of the code reader groups includes a plurality of the code readers arranged along the arrangement direction of the grating blades; One of the code readers corresponds to one grating blade in one of the blade groups, and the code reader is used to read the position of the corresponding grating blade.

2. The multileaf collimator according to claim 1, characterized in that: n is greater than 1, and the position detection device further comprises: A guide rail and a grating ruler fixed on the bracket, wherein the guide rail and the grating ruler are arranged in parallel and extend along the arrangement direction of the grating blades; A mechanical connection component is arranged on the guide rail, wherein one end of the mechanical connection component close to the grating ruler is fixedly connected to the grating head, and one end of the mechanical connection component away from the grating ruler is fixedly connected to the circuit board. The mechanical connection component moves on the guide rail to drive the circuit board and the grating head to move synchronously.

3. The multileaf collimator according to claim 2, characterized in that: The code reader includes an image acquisition module and an optical path module; The image acquisition module is mounted on the circuit board; The optical path module comprises a supporting unit and an imaging lens, an illumination light source and an illumination focusing lens mounted on the supporting unit. The supporting unit is mounted on the circuit board and straddles the image acquisition module.

4. The multileaf collimator according to claim 1, characterized in that: The code reader includes an image acquisition module and an optical path module; The optical path module comprises an optical fiber bundle, a lens support frame and an imaging lens arranged in the lens support frame, the extension direction of the optical fiber bundle is the same as the extension direction of the grating blade, the front end of the optical fiber bundle faces the code disk structure of the grating blade corresponding to it, and the rear end of the optical fiber bundle faces the imaging lens; The image acquisition module is installed directly above the lens support frame, and the image acquisition module or the lens support frame is directly installed on the circuit board.

5. The multileaf collimator according to claim 4, characterized in that: The position detection device also includes: a strip lighting module, the extension direction of which is parallel to the arrangement direction of the grating blades, and the strip lighting module is placed at the front end of the optical fiber bundle to provide lighting for the code disk structure of each grating blade in one of the blade groups.

6. The multileaf collimator according to claim 1, characterized in that: The grating blade has a through slot for accommodating the grating lead screw; The multi-leaf grating further comprises: 2 shielding devices, located outside the two sides of the 2*2 blade groups along the row direction, the shielding devices comprising a shielding plate and a plurality of couplings; The shielding plate has a plurality of through holes, the through holes are divided into a front hole portion facing the grating blades and a rear hole portion away from the grating blades, and the aperture of the front hole portion is smaller than the aperture of the rear hole portion; One coupling is arranged corresponding to one through hole and assembled in the rear hole portion of the corresponding through hole, and one grating motor is assembled on one coupling; A grating screw rod is arranged corresponding to a through hole and one end of the grating screw rod is assembled in the front hole portion of the corresponding through hole. The other end of the grating screw rod is accommodated in the through groove of the corresponding grating blade. The grating motor drives the corresponding grating blade in turn through the coupling and the grating screw rod.

7. The multileaf collimator according to claim 6, characterized in that: The shielding device further comprises a shielding shell having a plurality of openings, one coupling is arranged corresponding to one of the openings, and the grating motor assembled on the coupling is accommodated in the corresponding opening.

8. The multileaf collimator according to claim 1, characterized in that: Also includes: A heat dissipation device, the heat dissipation device comprising a water tank and at least one radiator connected by a circulation pipe, the water tank is located outside the blade group along the row direction, and the radiator is located outside the blade group along the arrangement direction of the grating blades; The water tank is a hollow structure, in which liquid is stored and the cavity has a plurality of hollow holes passing therethrough, and a grating motor driving the grating blades is arranged corresponding to and assembled in one of the hollow holes; The radiator comprises a box body and a fan located above the box body, the box body is used to store liquid and exchange liquid with the water tank, and the fan cools down the liquid in the box body.

Images