An assembly method and assembly apparatus for a silicon photomultiplier array

Abstract

The application relates to the technical field of detectors, and provides an assembling method and an assembling device of a silicon photomultiplier array, the assembling method comprises the steps of manufacturing a mounting die, pre-fixing the mounting die, pre-mounting silicon photomultipliers and mounting. The assembling device comprises the mounting die, and a limiting hole for accommodating the silicon photomultipliers is arranged on the mounting die. Compared with the prior art, the silicon photomultiplier array mounting technology improves the mounting precision of the silicon photomultiplier array, is beneficial to the collection of the scintillation light output by the silicon photomultiplier array in the PET detector, greatly improves the energy resolution, and has strong crystal resolution capability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detector, and particularly provides an assembling method and an assembling device of a silicon photomultiplier array. BACKGROUND

[0002] As a core device of PET detector, silicon photomultiplier is usually arranged in an array form to ensure a proper detection area to match the designed PET detector. Commercial silicon photomultiplier arrays provided by manufacturers usually have only 2-3 arrangement modes and arrangement numbers (4x4, 8x8). When designing a PET detector system, the area of the actual required silicon photomultiplier array is usually different from the standard size provided by the manufacturer. One solution to this problem is to customize the required size of the silicon photomultiplier array from the manufacturer, which is very expensive. Another solution is to design and self-assemble a silicon photomultiplier array (such as 3x3, 6x6, 10x10) of the required size by using single silicon photomultipliers from a PCB mounting manufacturer in the PET detector manufacturing practice. For the traditional printed circuit board surface mounting technology, the mounted components are prone to interference and collision with each other. The gap between the single silicon photomultipliers in the mounted array is large (for example, there is a gap of 0.2mm-0.4mm). For small size silicon photomultipliers, the large gap will result in low detection efficiency of the assembled silicon photomultiplier array, or even mounting failure. SUMMARY

[0003] The present application aims to provide an assembling method and an assembling device of a silicon photomultiplier array, and aims to solve the problem of low assembly efficiency of the existing silicon photomultiplier array.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0005] An assembling method of a silicon photomultiplier array, the assembling method comprising:

[0006] manufacturing a mounting mold, taking a glass substrate, and opening a limiting hole for accommodating a silicon photomultiplier array on the glass substrate as a mounting mold; mounting mold pre-fixing, determining a to-be-mounted position on a PCB, and fixing the mounting mold on the PCB so that the limiting hole encloses the to-be-mounted position; silicon photomultiplier pre-mounting, placing a plurality of silicon photomultipliers to be mounted in the limiting hole of the mounting mold, and adhering each silicon photomultiplier to the mounting mold to form an integral body, thereby obtaining an adhesive body; mounting, separating the adhesive body from the PCB, coating solder paste on the to-be-mounted position of the PCB, and recombining the adhesive body and the PCB to perform reflow soldering and remove the mounting mold, so as to obtain a silicon photomultiplier array on the PCB.

[0007] The application has the beneficial effect that the silicon photomultiplier array assembling method improves the mounting efficiency of the silicon photomultiplier array and reduces the gap between the silicon photomultipliers, which is conducive to the collection of the scintillation light output by the crystal in the PET detector, so that the energy resolution is greatly improved, and the crystal resolution capability is strong.

[0008] In one embodiment, in the step of fixing the mounting mold, a first positioning hole is formed on the PCB, and a second positioning hole is formed on the mounting mold, and the mounting mold is fixed on the PCB by cooperation of the first positioning hole and the second positioning hole; or a positioning column is arranged on the PCB, and a containing hole is formed on the mounting mold, and the mounting mold is fixed on the PCB by inserting the positioning column into the containing hole.

[0009] In one embodiment, in the step of pre-mounting the silicon photomultipliers, a cover plate is prepared for cooperation with the limiting hole; while the plurality of silicon photomultipliers to be mounted are placed in the limiting hole of the mounting mold, the silicon photomultipliers already placed in the limiting hole are aligned by pressing down through the cover plate.

[0010] In one embodiment, in the step of pre-mounting the silicon photomultipliers, a notch is formed on the mounting mold and communicates with the limiting hole, and at least the last silicon photomultiplier enters the limiting hole through the notch during the process of placing the plurality of silicon photomultipliers to be mounted in the limiting hole of the mounting mold.

[0011] In one embodiment, the size of the limiting hole is the same as the sum of the sizes of the plurality of silicon photomultipliers to be mounted.

[0012] The application further provides an assembling device, which is assembled by using the silicon photomultiplier array assembling method as described above, and the assembling device comprises a mounting mold, and the mounting mold is provided with a limiting hole for accommodating a silicon photomultiplier.

[0013] The application has the beneficial effect that the silicon photomultiplier array assembling device is used for assembling the silicon photomultiplier array, which is conducive to the assembly of the silicon photomultiplier, greatly improves the mounting efficiency of the silicon photomultiplier array, and reduces the gap between the silicon photomultipliers.

[0014] In one embodiment, the assembling device further comprises a cover plate for cooperation with the mounting mold, and the cover plate is adapted to the shape and size of the limiting hole.

[0015] In one embodiment, a notch is formed on the mounting mold and communicates with the limiting hole, and the silicon photomultiplier enters the limiting hole through the notch.

[0016] In one embodiment, the mounting mold is provided with a positioning structure for fixing the PCB; the positioning structure comprises a first positioning hole formed on the PCB and a second positioning hole formed on the mounting mold, and the first positioning hole and the second positioning hole are used in cooperation; or the positioning structure comprises a positioning column formed on the PCB and a containing hole formed on the mounting mold, and the positioning column and the containing hole are used in cooperation.

[0017] In one embodiment, the size of the limiting hole is the same as the sum of the sizes of the silicon photomultipliers to be mounted. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0019] Figure 1 The assembly method flow chart of the silicon photomultiplier array provided by the embodiment of the present application;

[0020] Figure 2 The assembly device structure schematic diagram of the silicon photomultiplier array provided by the embodiment of the present application;

[0021] Figure 3 The assembly device structure schematic diagram of the silicon photomultiplier array provided by the embodiment of the present application;

[0022] Figure 4a The effect of the silicon photomultiplier array after using the traditional PCB surface mounting method;

[0023] Figure 4b The effect diagram of the silicon photomultiplier array assembled by using the embodiment of the present application.

[0024] In the drawings, various reference signs represent:

[0025] 1, mounting mold; 2, limiting hole; 3, cover plate; 4, notch; 5, PCB; 6, first limiting hole; 7, second limiting hole; 8, silicon photomultiplier. DETAILED DESCRIPTION

[0026] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals and characters throughout the figures denote the same elements or elements having the same function. The embodiments described below are exemplary and are intended to provide examples of the present application, and are not intended to limit the present application.

[0027] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0028] In addition, the terms "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features referred to. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0029] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] Please refer to Figure 1 , Figure 3 The assembly method of the silicon photomultiplier array of the embodiment of the present application comprises:

[0031] S001, manufacturing a mounting mold 1; taking a glass substrate, opening a limiting hole 2 for accommodating a silicon photomultiplier array on the glass substrate as a mounting mold 1. In step S001, the mounting mold 1 is manufactured by using a high-temperature-resistant material, which can be manufactured by using a high-temperature-resistant glass as a substrate and using a laser processing method, or can be manufactured by using a high-temperature-resistant polymer material and using a 3D printing method. Both methods can meet the requirements of the PET detector silicon photomultiplier array assembly method, such as high precision, small error, and high temperature resistance. The high-precision glass plate is manufactured by using laser processing, which is low in cost and transparent to light, facilitating observation and correction of the array during mounting and rapid adjustment according to different sizes of the PET detector SiPM array. The size and shape of the limiting hole 2 can be designed according to actual needs. For example, the hole shape and size of the limiting hole can be designed to be consistent with the size of the array to be assembled, so as to further improve the array mounting precision, so that the gap between adjacent silicon photomultipliers 8 in the array is narrow or even seamless, thereby reducing or avoiding the problem of poor stability of the corresponding detector caused by leakage of liquid silicon oil (optical adhesive); of course, the hole shape and size of the limiting hole 2 can also be slightly larger than the size of the array to be assembled, so that the silicon photomultipliers to be assembled can be easily placed in the limiting hole, thereby further improving the assembly efficiency;

[0032] S002, pre-fixing the mounting mold 1; determining the mounting position on the PCB 5, fixing the mounting mold 1 on the PCB 5, so that the limiting hole 2 encloses the mounting position; the pre-fixing needs to ensure that the silicon photomultiplier 8 in the mounting plate can be electrically connected with the PCB 5 when the silicon photomultiplier 8 is fixed on the PCB 5;

[0033] S003, pre-mounting the silicon photomultiplier 8; placing the plurality of silicon photomultipliers 8 to be mounted one by one in the limiting hole 2 of the mounting mold 1, arranging them in order, and bonding the arranged silicon photomultipliers 8 and the mounting mold 1 to form an integrated body. When bonding, KAPTON high-temperature-resistant tape can be used, or the same type of high-temperature-resistant tape can be used to bond the silicon photomultiplier array and the mounting mold 1 from the top of the silicon photomultiplier (the bottom is the PCB 5);

[0034] S004, mounting; separating the integrated body from the PCB 5, i.e. moving the PCB 5 out from the bonded silicon photomultiplier array and the mounting mold 1 (i.e. the integrated body), and coating the mounting position of the PCB 5 with solder paste, and then recombining the integrated body and the PCB 5, and performing high-temperature reflow soldering to remove the mounting mold 1, so as to obtain the silicon photomultiplier array on the PCB 5.

[0035] The assembling method of the embodiment makes the PET detector silicon photomultiplier array capable of being assembled manually or using a chip mounter, which makes up for the defect of single printed circuit board surface mount method in the field of PET detector silicon photomultiplier array.

[0036] The method for assembling the silicon photomultiplier array solves the problem of large gap between single silicon photomultiplier 8 caused by traditional process in the field of PET detector silicon photomultiplier array. The silicon photomultiplier array assembled by the assembling technology has a significantly reduced gap and accurate positioning. Since the gap of the assembled silicon photomultiplier array is greatly reduced, the problem of easy outflow of silicon oil as a light adhesive when the crystal array and the silicon photomultiplier array are bonded in the process of assembling the silicon photomultiplier array is solved, which ensures the stable performance of the PET detector.

[0037] Please refer to Figure 4a and Figure 4b , wherein, Figure 4a is the effect of the silicon photomultiplier array after using the traditional PCB surface mount method; Figure 4b is an effect diagram of the silicon photomultiplier array assembled by using the embodiment of the present application. Compared with the prior art, the assembling technology of the embodiment improves the assembling precision of the silicon photomultiplier array, which is beneficial to the collection of the scintillation light output by the crystal in the PET detector, greatly improves the energy resolution, and has strong crystal resolution capability.

[0038] In one embodiment, the mounting mold 1 is fixed on the PCB 5, which can be specifically achieved by setting a positioning part on the PCB 5 and the mounting plate, so as to keep the relative position of the mounting plate and the PCB 5 unchanged by using the positioning part. Specifically, but not limited to, in the step of fixing the mounting mold 1, a first positioning hole 6 is formed on the PCB 5, and a second positioning hole 7 is formed on the mounting mold 1. The mounting mold 1 is fixed on the PCB 5 by using the first positioning hole 6 and the second positioning hole 7 in cooperation. The first positioning hole 6 and the second positioning hole 7 can be aligned by using them in cooperation, which can be specifically achieved by naked eye or with the help of auxiliary means such as laser. Preferably, in order to more efficiently and quickly align the mounting plate and the PCB 5, the first positioning hole 6 and the second positioning hole 7 are aligned, which can be specifically achieved by, but not limited to, setting a positioning column in the first positioning hole 6, and aligning the positioning column with the second positioning hole 7. The positioning column can be a protruding structure made of high-temperature-resistant metal needle or other high-temperature-resistant materials, such as a bump, a tooth, etc. The shape and size of the positioning column are adapted to the second positioning hole 7.

[0039] Or, a positioning column is arranged on the PCB 5, a containing hole is arranged on the mounting mold 1, and the mounting mold 1 is fixed on the PCB 5 by inserting the positioning column into the containing hole, so that the mounting mold 1 is arranged at the frame of the PCB 5.

[0040] In one embodiment, for the array with a large number of silicon photomultipliers 8, it is easy to squeeze out the adjacent silicon photomultipliers 8 during the assembly process. In order to assist the array assembly, a cover plate 3 is prepared in the step of pre-mounting the silicon photomultipliers 8, and the cover plate 3 is used in cooperation with the limiting hole 2. When the plurality of silicon photomultipliers 8 to be mounted are placed in the limiting hole 2 of the mounting mold 1, the cover plate 3 is used to press and align the silicon photomultipliers 8 placed in the limiting hole 2.

[0041] Specifically, the cover plate 3 is used to assist the array assembly to improve the assembly efficiency, and the plurality of silicon photomultipliers 8 to be mounted are efficiently placed on the mounting plate, which can be designed as follows: the single silicon photomultiplier 8 is sequentially placed in the clamping groove of the mounting mold 1, and the upper surface of the silicon photomultiplier 8 placed in the limiting hole 2 is covered by the upper cover plate 3 at the same time, until all the silicon photomultipliers 8 are placed in the limiting hole 2 of the mounting mold 1.

[0042] In one embodiment, in order to solve the problem that the last silicon photomultiplier 8 is not easy to be placed in the limiting hole 2 of the mounting mold 1 during the assembly process of the silicon photomultiplier array, a notch 4 is arranged on the mounting mold 1 in the step of pre-mounting the silicon photomultipliers 8, and the notch 4 is in communication with the limiting hole 2. During the process of placing the plurality of silicon photomultipliers 8 to be mounted in the limiting hole 2 of the mounting mold 1, the last silicon photomultiplier 8 enters the limiting hole 2 through the notch 4.

[0043] In one embodiment, in order to overcome the problem that the silicon photomultiplier array assembled by the existing array assembly technology often has a large gap and it is difficult to realize the zero-gap assembly of the array by manual assembly, the size of the limiting hole 2 is designed to be the same as the sum of the sizes of the plurality of silicon photomultipliers 8 to be mounted. In this way, when the last silicon photomultiplier 8 is placed in the clamping groove, all the silicon photomultipliers 8 just fill the clamping groove, and the zero-gap silicon photomultiplier array can be realized.

[0044] Exemplarily, in one embodiment, 16 silicon photomultipliers 8 are used for 4x4 splicing, first, 15 silicon photomultipliers 8 are sequentially placed into the limiting hole 2, the size of the limiting hole 2 is just the same as the splicing size of the silicon photomultiplier 8, so that the silicon photomultiplier 8 is seamlessly spliced. Then the cover plate 3 is used to fix the 15 silicon photomultipliers 8 that have been placed, save the 15 silicon photomultipliers 8 in the same plane, then push the last silicon photomultiplier 8 into the gap 4, which can ensure that the flatness of the 15 silicon photomultipliers 8 is not damaged. After the 16 silicon photomultipliers 8 are spliced, only the last silicon photomultiplier 8 is pressed, the upper cover plate 3 is removed, and the silicon photomultiplier 8 array and the device are fixed using high-temperature tape.

[0045] Please refer to Figure 2 、 Figure 3 The embodiment of the present application also provides an assembly device, which is assembled by using the assembly method of the silicon photomultiplier array described above, and the assembly device comprises a mounting mold 1, and the mounting mold 1 is provided with a limiting hole 2 for accommodating the silicon photomultiplier 8. The material of the mounting mold 1 is high-temperature-resistant glass, which can be processed by cutting, 3D printing and the like. The mounting mold 1 can be designed as a glass plate or any mounting plate that can be used for mounting the silicon photomultiplier array, and the shape and size of the mounting mold 1 are adapted to the PCB 5.

[0046] With the mounting mold 1 provided by the embodiment of the present application, the assembly efficiency of the silicon photomultiplier array and the stability of the positron emission tomography (PET) detector are greatly improved, the difficulty of array mounting is reduced, and the problems of complex mounting process and large error of the silicon photomultiplier array in the PET detector due to the lack of the mounting mold 1 are solved.

[0047] In one embodiment, the assembly device further comprises a cover plate 3 used in cooperation with the mounting mold 1, and the shape and size of the cover plate 3 are adapted to the shape and size of the limiting hole 2.

[0048] The size of the cover plate 3 can be designed according to actual needs. For example, in order to save materials, the upper cover plate 3 can be designed to have an area smaller than that of the limiting hole 2, and in order to facilitate the placement of the silicon photomultiplier 8 to be mounted in the limiting hole 2, the cover plate 3 can be designed to have an area greater than or equal to that of the limiting hole 2.

[0049] In one embodiment, the mounting mold 1 is provided with a gap 4 connected with the limiting hole 2, and the silicon photomultiplier 8 enters the limiting hole 2 through the gap 4. In the embodiment of the present application, the problem that the last silicon photomultiplier is not easy to be placed into the limiting hole 2 of the mounting mold 1 in the splicing process of the silicon photomultiplier array is solved.

[0050] In one embodiment, the mounting mold 1 is provided with a positioning structure for fixing the PCB 5;

[0051] Please refer to Figure 1 and Figure 3 The positioning structure comprises a first positioning hole 6 formed on the PCB 5 and a second positioning hole 7 formed on the mounting mold 1, and the first positioning hole 6 and the second positioning hole 7 are used in cooperation.

[0052] Alternatively, the positioning structure comprises a positioning column formed on the PCB 5 and a receiving hole formed on the mounting mold 1, and the positioning column and the receiving hole are used in cooperation.

[0053] The mounting plate and the PCB 5 are kept in a relative position by the positioning part, and the mounting mold 1 can be fixed on the PCB 5 by using the first positioning hole 6 and the second positioning hole 7 in cooperation. The first positioning hole 6 and the second positioning hole 7 can be aligned by the naked eye or with the help of auxiliary means such as laser. Preferably, to align the mounting plate and the PCB 5 more efficiently and quickly, the first positioning hole 6 and the second positioning hole 7 are aligned, which specifically includes but is not limited to: a positioning column is arranged in the first positioning hole 6, and the positioning column is aligned and sleeved in the second positioning hole 7. The positioning column can be a protruding structure made of a high-temperature-resistant metal needle or other high-temperature-resistant materials, such as a bump, a protruding tooth, etc. The shape and size of the positioning column are adapted to the second positioning hole 7.

[0054] The first positioning hole 6 can be formed by laser drilling, mechanical drilling, etc., the positioning column can be formed by gluing, mold making, etc., and the second positioning hole 7 / receiving hole can be processed by laser drilling, mechanical drilling, etc.

[0055] According to the size of the mounting plate, the number of positioning parts (i.e. the first positioning hole 6 and the second positioning hole 7 used in cooperation, or the positioning column and the receiving hole used in cooperation) can be designed to be two pairs or more.

[0056] In one embodiment, the size of the limiting hole 2 is the same as the sum of the sizes of each silicon photomultiplier 8 to be mounted. This design solves the problem of large gaps in the existing manually assembled silicon photomultiplier array, and the mounting mold 1 of the embodiment of the application ensures the effect of zero gap between the single silicon photomultipliers 8 in the array assembled by hand.

[0057] Combined with the design of the notch 4 and the cover plate 3, the embodiment of the application can easily realize the assembly of a large-size silicon photomultiplier array such as 4x4. When the last silicon photomultiplier 8 is put into the card slot, all the silicon photomultipliers 8 just fill the card slot, realizing zero-gap assembly of a large-size silicon photomultiplier array.

[0058] The above merely describes preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of assembling an array of silicon photomultipliers, characterized by, The assembling method comprises: manufacturing a mounting mold, taking a glass substrate, and opening a limiting hole for accommodating a silicon photomultiplier array on the glass substrate as the mounting mold; mounting mold pre-fixing, determining a to-be-mounted position on a PCB, and fixing the mounting mold on the PCB so that the limiting hole encloses the to-be-mounted position; silicon photomultiplier pre-mounting, placing a plurality of silicon photomultipliers to be mounted in the limiting hole of the mounting mold, and adhering each silicon photomultiplier to the mounting mold to form an integrated body, thereby obtaining an adhered body; mounting, separating the adhered body from the PCB, applying solder paste on the to-be-mounted position of the PCB, recombining the adhered body and the PCB, reflow soldering, and removing the mounting mold to obtain a silicon photomultiplier array on the PCB.

2. The method of assembling a silicon photomultiplier array of claim 1, wherein: In the step of mounting mold pre-fixing, a first positioning hole is opened on the PCB, and a second positioning hole is opened on the mounting mold, and the mounting mold is fixed on the PCB by cooperation of the first positioning hole and the second positioning hole. Alternatively, a positioning column is arranged on the PCB, and a containing hole is opened on the mounting mold, and the mounting mold is fixed on the PCB by passing the positioning column through the containing hole.

3. The method of assembling a silicon photomultiplier array of claim 1, wherein: In the step of silicon photomultiplier pre-mounting, a cover plate cooperating with the limiting hole is prepared, and each silicon photomultiplier placed in the limiting hole is aligned by pressing through the cover plate.

4. The method of assembling an array of silicon photomultipliers according to any of claims 1-3, characterized in that: In the step of silicon photomultiplier pre-mounting, a notch communicating with the limiting hole is opened on the mounting mold, and at least the last silicon photomultiplier enters the limiting hole through the notch during the process of placing a plurality of silicon photomultipliers to be mounted in the limiting hole of the mounting mold.

5. The method of assembling a silicon photomultiplier array of claim 1, wherein: The size of the limiting hole is the same as the sum of the sizes of each silicon photomultiplier to be mounted.

6. An assembly apparatus characterized by: The assembly device adopts the assembling method of the silicon photomultiplier array according to any one of claims 1 to 5, and comprises a mounting mold provided with a limiting hole for accommodating a silicon photomultiplier.

7. The assembly apparatus of claim 6, wherein: The assembly device further comprises a cover plate cooperating with the mounting mold, and the cover plate is adapted to the shape and size of the limiting hole.

8. The assembly apparatus of claim 6, wherein: A notch communicating with the limiting hole is opened on the mounting mold, and the silicon photomultiplier enters the limiting hole through the notch.

9. The assembly apparatus of claim 6, wherein: The mounting mold is provided with a positioning structure for fixing the PCB; The positioning structure comprises a first positioning hole opened on the PCB and a second positioning hole opened on the mounting mold, and the first positioning hole cooperates with the second positioning hole; Alternatively, the positioning structure comprises a positioning column opened on the PCB and a containing hole opened on the mounting mold, and the positioning column cooperates with the containing hole.

10. The assembly apparatus of claim 6, wherein: The size of the limiting hole is same as the sum of the sizes of each of the to-be-mounted silicon photomultipliers.

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