Free operation single photon detector with high refrigeration efficiency

Abstract

The utility model discloses a free operation single photon detector with high refrigeration efficiency, which comprises a shell (1), a heat radiator module (2), a PCB (3) and a secondary refrigeration module (5), the secondary refrigeration module (5) comprises an NFAD (5-A) and a multilayer TEC (5-D) which are arranged up and down, the heat radiator module (2) comprises a heat radiator (2-A) and a fan (2-B) installed on the heat radiator, the PCB (3) is fixed above the heat radiator module (2), and the PCB (3) is fixed above the heat radiator module (2). And the secondary refrigeration module (5) is placed at the opening in the middle of the PCB (3), and the bottom surface of the secondary refrigeration module (5) is in contact with the radiating surface on the radiator (2-A). By means of the structural design of the two-stage refrigeration module and the structural design of the radiator module, multi-stage refrigeration can be achieved, and rapid heat exchange of core devices is achieved.

Description

Technical Field

[0001] This patent belongs to the field of photoelectric detection equipment, specifically a free-running single-photon detector with high cooling efficiency. Background Art

[0002] At present, free-running single-photon detection technology generally uses negative feedback avalanche diodes (NFADs) as core detection devices, which can achieve rapid quenching of avalanche current and suppress after-pulse effects, providing solutions for applications of asynchronous weak-light detection such as quantum communication, lidar, and fluorescence lifetime detection.

[0003] During operation, the lower the ambient temperature of the NFAD, the better the detection efficiency. However, the traditional thermoelectric cooler (TEC) requires a large amount of power to achieve the low-temperature cooling target, and the heat exchange efficiency between devices is low, which limits the detection efficiency.

[0004] The Chinese patent "Single-photon detector cooling device and equipment" with application number CN202220549806.6 discloses a cooling device and equipment for a single-photon detector, including a heat sink, a multi-layer thermoelectric cooler TEC, a thermally conductive film and a photodetector, wherein a through hole for placing the single-photon detector is provided inside the heat sink; the multi-layer thermoelectric cooler TEC includes N layers of thermoelectric coolers TEC; the thermally conductive film is hollow inside and fixedly arranged on the top of the multi-layer thermoelectric cooler TEC; one end of the photodetector is fixedly arranged inside the heat sink, effectively utilizing the cold surface of the first layer of thermoelectric cooler in the multi-layer thermoelectric cooler TEC, thereby achieving effective cooling of the single-photon detector and ensuring the stability of the performance of the single-photon detector. However, the refrigeration device has a single cooling method, and the components are separated and connected individually, with poor fastening effect. During actual use, the components may become loose or even detach from each other. During the rapid cooling process, the pin surface of the photodetector and the single-photon detector is lower than the ambient temperature. When the humid and hot ambient air encounters a surface below the dew point, water vapor condenses to produce condensation, resulting in reduced working efficiency of the device or even failure, thereby reducing the service life of the equipment.

[0005] The Chinese patent "A Refrigeration Structure and Single-Photon Detection Device" with application number CN202010244596.5 discloses a refrigeration box structure, including multiple refrigeration boxes arranged side by side, each refrigeration box is individually packaged, including a heat sink, a shell, a TEC cooler, a bias plate, an APD tube (avalanche photodiode) and an optical fiber connector. The TEC cooler, the bias plate, and the APD tube are fixed inside the shell, and the heat sink is fixed to the outside of the shell. The optical fiber connector extends into the interior of the refrigeration box through the optical fiber connection hole, and is used to connect the optical fiber of the APD tube in the refrigeration box and the transmission optical fiber outside the refrigeration box. By arranging multiple refrigeration boxes side by side to form a refrigeration structure, when a channel fails, only the corresponding refrigeration box needs to be removed and repaired, which will not affect other channels, thereby improving the stability of the product. However, the core component of the device adopts a traditional APD tube, and the heat dissipation method is to transfer heat through the contact between the tube wall and the tube clamp, and the heat exchange effect is not good. Utility Model Content

[0006] The technical problem to be solved by the utility model is how to improve the cooling efficiency of a free-running single-photon detector.

[0007] The utility model solves the above-mentioned technical problems through the following technical means: a free-running single-photon detector with high cooling efficiency, comprising a housing (1), a heat sink module (2), a PCB board (3), and a secondary cooling module (5); the heat sink module (2), the PCB board (3), and the secondary cooling module (5) are all wrapped in the housing (1); the secondary cooling module (5) comprises an NFAD (5-A) and a multilayer TEC (5-D) arranged up and down; the heat sink module (2) comprises a heat sink (2-A) and a fan (2-B) mounted on the heat sink; the PCB board (3) is fixed above the heat sink module (2); the secondary cooling module (5) is placed at the middle opening of the PCB board (3), and the bottom surface of the secondary cooling module (5) is in contact with the heat dissipation surface on the heat sink (2-A).

[0008] As an optimized technical solution, the secondary refrigeration module (5) is provided with NFAD (5-A), a copper block base (5-B), a plastic pressing block (5-C) and a multilayer TEC (5-D) in sequence from top to bottom, the bottom surface of the multilayer TEC (5-D) is in contact with the upper surface of the heat sink (2-A), the copper block base (5-B) is fixed on the plastic pressing block (5-C) and in contact with the top surface of the multilayer TEC (5-D).

[0009] As an optimized technical solution, the plastic pressing block (5-C) is a ring frame, which is nested around the multi-layer TEC (5-D), and a groove structure is provided at the bottom to press the bottom layer of the multi-layer TEC (5-D). The plastic pressing block (5-C) is fixed on the surface of the heat sink (2-A), and the multi-layer TEC (5-D) is fixedly installed between the heat sink (2-A) and the plastic pressing block (5-C). The NFAD (5-A) is fixedly installed in a groove opened on the upper surface of the copper block base (5-B).

[0010] As an optimized technical solution, the free-running single-photon detector with high cooling efficiency further comprises a shielding cover module (4), and the secondary cooling module (5) is wrapped in a closed space formed by the shielding cover module (4).

[0011] As an optimized technical solution, the material of the shielding cover module (4) is aluminum alloy, and the internal space of the shielding cover module (4) is filled with foam.

[0012] As an optimized technical solution, the tail end of the optical fiber of the NFAD (5-A) passes through the optical fiber hole (406) arranged at the bottom of the side of the shielding cover module (4), and the gap of the optical fiber hole (406) is filled with glue.

[0013] As an optimized technical solution, the shielding cover module (4) is located at a corner of the radiator module (2), the upper end of the radiator module (2) extends out of the mounting column (202), the PCB board (3) is fixed on the mounting column (202), there are three mounting columns (202), and a corner of the PCB board (3) that is not fixed on the mounting column (202) is supported and fixed by the shielding cover module (4).

[0014] As an optimized technical solution, the heat sink module (2) further comprises a protruding boss structure (203), wherein the boss structure (203) is in contact with a high-heat chip on the PCB board (3).

[0015] As an optimized technical solution, the shielding cover module (4) comprises a shielding cover upper cover (4-A), a shielding cover (4-B), and a shielding cover ring frame (4-C); the bottom of the shielding cover module (4) is hollow, the shielding cover upper cover (4-A) covers the shielding cover (4-B), the PCB board (3) is clamped between the shielding cover (4-B) and the shielding cover ring frame (4-C), and an opening is provided on the clamped portion of the PCB board (3).

[0016] As an optimized technical solution, a plurality of threaded holes (201) are arranged on the side of the radiator (2-A), and screws are passed through the mounting holes of the fan (2-B) and fixed on the threaded holes (201) to achieve the installation of the fan (2-B). The radiator (2-A) is provided with a cavity corresponding to the position where the fan (2-B) is installed, and the fan (2-B) is integrally sunken into the radiator (2-A).

[0017] The advantages of the utility model are:

[0018] 1. The utility model can realize multi-stage refrigeration and rapid heat exchange of core components through the structural design of the secondary refrigeration module and the structural design of the radiator module;

[0019] 2. Wrap the secondary refrigeration module in a closed space that isolates the air to prevent the device from being exposed to the air. During the rapid refrigeration process, the temperature of the pin part of the free-running single-photon detector with high refrigeration efficiency is prevented from being lower than the ambient temperature, which effectively solves the condensation problem and enhances the environmental adaptability;

[0020] 3. The secondary refrigeration module adopts a copper block base and a plastic pressing block to improve the installation stability and heat dissipation effect of the refrigeration device;

[0021] 4. The installation method of the secondary refrigeration module increases the tightness of the secondary refrigeration module. Using the integrated NFAD design, the APD chip is integrated and welded inside the NFAD without welding the pins to the circuit board, so there is no need to reserve a certain space for operation, which further realizes the miniaturized design. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an exploded view of a free-running single-photon detector with high cooling efficiency according to an embodiment of the utility model;

[0023] Figure 2 It is an exploded view of the housing in the embodiment of the utility model;

[0024] Figure 3 This is an internal structure diagram of a free-running single-photon detector with high cooling efficiency according to an embodiment of the utility model;

[0025] Figure 4 is a structural diagram of a radiator module in an embodiment of the utility model;

[0026] Figure 5 It is a relative position structure diagram of the shielding cover module, the PCB board, and the secondary refrigeration module in the embodiment of the utility model;

[0027] Figure 6 It is a structural diagram of a two-stage refrigeration module in an embodiment of the utility model;

[0028] Figure 7 It is an exploded view of the secondary refrigeration module in the embodiment of the utility model;

[0029] Figure 8 It is a cross-sectional view of NFAD in an embodiment of the present utility model. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] See also Figure 1 As shown, the utility model proposes a free-running single-photon detector with high cooling efficiency, including a housing 1, a heat sink module 2, a PCB board 3, a shielding cover module 4, and a secondary cooling module 5. The heat sink module 2, the PCB board 3, the shielding cover module 4, and the secondary cooling module 5 are all wrapped in the housing 1, the PCB board 3 is fixed above the heat sink module 2, the PCB board 3 is clamped in the middle of the shielding cover module 4, the bottom of the shielding cover module 4 is empty and fixed on the upper surface of the heat sink 2-A, the clamped part of the PCB board 3 is provided with an opening, the secondary cooling module 5 is placed at the middle opening of the PCB board 3, the overall structure of the secondary cooling module 5 is sealed in the shielding cover module 4, and the bottom surface is in contact with the heat dissipation surface on the heat sink module 2.

[0032] Figure 2 The exploded view of the housing 1, wherein 1-A is the front panel, 1-B is the U-shaped ring frame, 1-C is the rear panel, and 1-D is the upper cover. The front panel 1-A, the rear panel 1-C, the ring frame 1-B, and the upper cover 1-D together form a square housing 1. The positions and numbers of the boss structures on the front panel 1-A and the rear panel 1-C are consistent. Specifically, the boss structures 101 at both ends of the upper side of the front panel 1-A, the boss structures 103 at both ends of the lower side, the boss structures at both ends of the upper side of the rear panel 1-C (not shown in the figure), and the boss structures at both ends of the lower side (not shown in the figure) are respectively fixed to the mounting holes 102 (4) on the upper side of the side plate on the ring frame 1-B and the mounting holes 104 (4) on the lower side of the side plate by screws, and the boss structures 106 on the upper cover 1-D and the mounting holes 105 at both ends of the upper side of the rear panel 1-C are fixed by screws.

[0033] Figure 3This is a diagram of the internal structure of the detector. The PCB board 3 is fixed above the radiator module 2. The shielding cover module 4 is located at a corner of the radiator module 2. The PCB board 3 passes through the shielding cover module 4 and divides the shielding cover module 4 into two parts, an upper part and an lower part. The circuit module where the high-performance chip on the PCB board 3 is located is clamped in the middle of the shielding cover module 4. This design can perform electromagnetic shielding and is used to assist in supporting and fixing the PCB board 3. The bottom of the shielding cover module 4 is fixed to the upper surface of the radiator module 2 by screws.

[0034] Figure 4 The structure diagram of the radiator module 2 includes a radiator 2-A and a fan 2-B. After the radiator 2-A is milled, the upper end thereof extends out of the mounting column 202. Figure 3 The PCB board 3 is fixed on the mounting column 202, and there are actually only three mounting columns 202. The corner of the PCB board 3 that is not fixed on the mounting column 202 is supported and fixed by the shielding cover module 4. The other protruding boss structures 203 on the radiator 2-A are in contact with the high-heat chip on the PCB board 3 to achieve rapid heat exchange. A plurality of threaded holes 201 are arranged on the side of the radiator 2-A. The screws are passed through the mounting holes of the fan 2-B and fixed on the threaded holes 201 to achieve the installation of the fan 2-B, thereby reducing the number of parts required for installing the fan 2-B. The radiator 2-A is provided with a cavity corresponding to the position where the fan 2-B is installed. The fan 2-B is integrally sunken into the radiator 2-A, and the wind direction of the fan 2-B corresponds to the direction of the fins.

[0035] Figure 5 It is a structural diagram of the relative positions of the shielding cover module 4, the PCB board 3 and the secondary refrigeration module 5. The shielding cover module 4 includes a shielding cover upper cover 4-A, a shielding cover 4-B and a shielding cover ring frame 4-C. The bottom of the shielding cover module 4 is empty, the shielding cover upper cover 4-A covers the shielding cover 4-B, the PCB board 3 is clamped between the shielding cover 4-B and the shielding cover ring frame 4-C, and an opening is set on the clamped part of the PCB board 3, dividing the shielding cover module 4 into two upper and lower parts, thereby forming an upper and lower cavity with an opening in the middle, and the upper cavity, i.e., the space contained in the shielding cover 4-B, accommodates the high-performance chip on the PCB board 3.

[0036] See also Figure 6, is a structural diagram of a secondary refrigeration module 5, wherein the secondary refrigeration module 5 is placed at the middle opening of the PCB board 3, and the overall structure of the secondary refrigeration module 5 runs through the upper and lower cavities. The secondary refrigeration module 5 includes a NFAD 5-A, a copper block base 5-B, a plastic pressing block 5-C, and a multilayer TEC 5-D which are sequentially arranged from top to bottom. Specifically, the shape of the opening of the PCB board 3 matches the shape of the NFAD 5-A of the secondary refrigeration module 5, and the pins on both sides of the NFAD 5-A are welded on the PCB board 3, so that the NFAD 5-A is located in the upper cavity, i.e., the shielding cover 4-B. The copper block base 5-B, the plastic pressing block 5-C, and the multilayer TEC 5-D are fixed together and located in the lower cavity, i.e., the shielding cover ring frame 4-C. The NFAD 5-A is fixed by the copper block base 5-B located below the PCB board 3, and the tail end of the optical fiber is thrown out through the optical fiber hole 406 arranged at the bottom of the side of the shielding cover ring frame 4-C. After being fixed, the gap of the optical fiber hole 406 is filled with glue, so that the overall structure of the shielding cover module 4 forms a closed space. The shield cover upper cover 4-A and the shield cover 4-B are fixed with screws through mounting holes 401 and 402 (four holes each), and the PCB board 3 is fixed with screws through mounting holes 407 thereon and mounting holes 403 (four holes each) on the upper shield cover 4-B and mounting holes 404 (four holes each) on the lower shield cover ring frame 4-C, and the shield cover ring frame 4-C is fixed to the upper surface of the heat sink 2-A through bosses 405 around the bottom. The shield cover module 4 is made of aluminum alloy, and the structural design meets the requirements of electromagnetic shielding for high-performance chips on the PCB board 3. At the same time, the internal space of the shield cover module 4 is filled with foam, and the secondary refrigeration module 5 is wrapped in the enclosed space formed by the shield cover module 4 to prevent the device from being exposed to the air, effectively solving the condensation problem caused by rapid refrigeration.

[0037] Figure 7 This is an exploded view of the secondary refrigeration module 5. Figure 1 and Figure 4 The installation method of the secondary refrigeration module 5 can increase the installation stability of the secondary refrigeration module 5. The specific installation method is as follows:

[0038] STEP 1: The bottom surface of the multilayer TEC 5-D is in contact with the upper surface of the heat sink 2-A, which can transfer the heat from the bottom hot surface to the heat sink 2-A to achieve a rapid heat exchange effect;

[0039] STEP2: The plastic pressing block 5-C can be designed as a ring frame, which is nested around the multi-layer TEC 5-D. At the same time, a groove structure is provided at the bottom to press the bottom layer of the multi-layer TEC 5-D. Through holes 504 are provided at the four corners of the plastic pressing block 5-C. Screws pass through the through holes 504 and are fixed to the surface mounting holes of the heat sink 2-A, so that the multi-layer TEC 5-D is fixedly installed between the heat sink 2-A and the plastic pressing block 5-C.

[0040] STEP3: The copper block base 5-B is located above the plastic pressing block 5-C and contacts the top surface of the multilayer TEC 5-D. The copper block base 5-B and the plastic pressing block 5-C share the same set of mounting through holes 503 and 504 (four holes each). The copper block base 5-B is fixed to the plastic pressing block 5-C by screws and presses the top surface of the multilayer TEC 5-D.

[0041] STEP 4: NFAD 5-A is located above the copper block base 5-B. A groove is provided on the upper surface of the copper block base 5-B. Threaded holes 502 for fixing NFAD 5-A are provided at the four corners of the groove. NFAD 5-A is placed in the groove of the copper block base 5-B. NFAD 5-A is fixedly installed on the copper block base 5-B by screws passing through the mounting holes 501 of NFAD5-A. The copper material has high heat exchange efficiency and increases the contact area of ​​the hot surface of NFAD 5-A.

[0042] See also Figure 8 , is a cross-sectional view of NFAD 5-A, NFAD 5-A includes an optical fiber 5-A-1, a chip 5-A-2, a temperature sensor 5-A-3, an internal TEC 5-A-4 and a housing 5-A-5, wherein the optical fiber 5-A-1 and the internal TEC 5-A-4 are fixed on the housing 5-A-5, the chip 5-A-2 is disposed on the cold surface of the internal TEC 5-A-4, the temperature sensor 5-A-3 is located on the chip 5-A-2 and connected to the chip 5-A-2, and the temperature sensor 5-A-3 is used to monitor the internal temperature condition of NFAD 5-A and transmit a signal to the chip 5-A-2 for temperature control.

[0043] The multi-stage cooling strategy of the free-running single-photon detector with high cooling efficiency designed by the utility model is as follows: the internal TEC 5-A-4 of NFAD5-A can realize the primary cooling of NFAD 5-A and avoid the inefficient heat exchange of contact; by controlling the current direction and size of the multi-layer TEC 5-D, the secondary cooling effect can be realized on the basis of the primary cooling inside NFAD 5-A itself; the fan 2-B is provided on the radiator module 2 to power and operate, so that the heat of each chip of the detector can be blown away by forced air cooling, thereby realizing the three-stage cooling.

[0044] The utility model can adapt to different environments: when in a normal ventilation and room temperature environment (such as a laboratory), the device's internal TEC 5-A-4 and multi-layer TEC 5-D are used for two-stage cooling, and the fan is set to a sleep state, which can not only meet the heat dissipation needs, but also avoid problems such as the short life of the fan itself and the noise caused by operation; when in a harsh environment such as poor wind speed and high ambient temperature (such as an equipment room), the fan 2-B is controlled to operate for three-stage cooling, and rapid heat exchange is achieved through forced air cooling.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A free-running single-photon detector with high cooling efficiency, characterized in that: The invention comprises a housing (1), a heat sink module (2), a PCB board (3), and a secondary refrigeration module (5); the heat sink module (2), the PCB board (3), and the secondary refrigeration module (5) are all wrapped in the housing (1); the secondary refrigeration module (5) comprises an NFAD (5-A) and a multilayer TEC (5-D) arranged up and down; the heat sink module (2) comprises a heat sink (2-A) and a fan (2-B) mounted on the heat sink; the PCB board (3) is fixed above the heat sink module (2); the secondary refrigeration module (5) is placed at the middle opening of the PCB board (3), and the bottom surface of the secondary refrigeration module (5) is in contact with the heat dissipation surface on the heat sink (2-A).

2. A free-running single-photon detector with high cooling efficiency as claimed in claim 1, characterized in that: The secondary refrigeration module (5) is provided with NFAD (5-A), a copper block base (5-B), a plastic pressing block (5-C) and a multilayer TEC (5-D) in sequence from top to bottom, the bottom surface of the multilayer TEC (5-D) is in contact with the upper surface of the heat sink (2-A), the copper block base (5-B) is fixed on the plastic pressing block (5-C) and in contact with the top surface of the multilayer TEC (5-D).

3. A free-running single-photon detector with high cooling efficiency as claimed in claim 2, characterized in that: The plastic pressing block (5-C) is a ring frame, which is nested around the multi-layer TEC (5-D). At the same time, a groove structure is provided at the bottom to press the bottom layer of the multi-layer TEC (5-D). The plastic pressing block (5-C) is fixed on the surface of the heat sink (2-A), and the multi-layer TEC (5-D) is fixedly installed between the heat sink (2-A) and the plastic pressing block (5-C). The NFAD (5-A) is fixedly installed in a groove opened on the upper surface of the copper block base (5-B).

4. A free-running single-photon detector with high cooling efficiency as claimed in claim 1, characterized in that: It also comprises a shielding cover module (4), and the secondary refrigeration module (5) is wrapped in a closed space formed by the shielding cover module (4).

5. A free-running single-photon detector with high cooling efficiency as claimed in claim 4, characterized in that: The shielding cover module (4) is made of aluminum alloy, and the internal space of the shielding cover module (4) is filled with foam.

6. A free-running single-photon detector with high cooling efficiency as claimed in claim 4, characterized in that: The optical fiber tail end of the NFAD (5-A) passes through the optical fiber hole (406) arranged at the bottom of the side of the shielding cover module (4), and the gap of the optical fiber hole (406) is filled with glue.

7. A free-running single-photon detector with high cooling efficiency as claimed in claim 4, characterized in that: The shielding cover module (4) is located at a corner of the radiator module (2); a mounting column (202) extends out from the upper end of the radiator module (2); the PCB board (3) is fixed on the mounting column (202); there are three mounting columns (202); a corner of the PCB board (3) that is not fixed on the mounting column (202) is supported and fixed by the shielding cover module (4).

8. A free-running single-photon detector with high cooling efficiency as claimed in claim 7, characterized in that: The heat sink module (2) also includes a protruding boss structure (203), and the boss structure (203) is in contact with a high-heat chip on the PCB board (3).

9. A free-running single-photon detector with high cooling efficiency as claimed in claim 4, characterized in that: The shielding cover module (4) comprises a shielding cover upper cover (4-A), a shielding cover (4-B), and a shielding cover ring frame (4-C); the bottom of the shielding cover module (4) is hollow; the shielding cover upper cover (4-A) covers the shielding cover (4-B); the PCB board (3) is clamped between the shielding cover (4-B) and the shielding cover ring frame (4-C); and an opening is provided on the clamped portion of the PCB board (3).

10. A free-running single-photon detector with high cooling efficiency as claimed in claim 1, characterized in that: The radiator (2-A) is provided with a plurality of threaded holes (201) on its side, and screws are passed through mounting holes of the fan (2-B) and fixed on the threaded holes (201) to achieve mounting of the fan (2-B). The radiator (2-A) is provided with a cavity corresponding to the position where the fan (2-B) is mounted, and the fan (2-B) is integrally sunken into the radiator (2-A).

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