Refrigeration type infrared detector and thermal imager

Abstract

The utility model provides a refrigeration type infrared detector and a thermal imager, the refrigeration type infrared detector comprises a Dewar assembly and a refrigerating machine, the refrigerating machine comprises an expansion machine and a compressor, the expansion machine and the Dewar assembly are coaxially connected, the expansion machine and the compressor are communicated through a connecting pipe, and the Dewar assembly and the compressor are coaxially connected. The compressor is arranged on the side, away from the Dewar assembly, of the expansion machine, and the axis of the compressor is perpendicular to the axis of the Dewar assembly. According to the refrigeration type infrared detector and the thermal imager, the structural layout is reasonable, the heat dissipation effect of the refrigerator is enhanced, and the image degradation phenomenon caused by the temperature rise of the shutter can be effectively improved.

Description

Technical Field

[0001] This application relates to the technical field of infrared detection devices, and particularly to a refrigerated infrared detector and a thermal imager. Background Art

[0002] A gas infrared thermal imager is an imaging device that uses infrared thermal imaging technology to achieve visualization by photoelectrically converting the infrared radiation of a target object. It can visualize invisible gases and can be used to detect gas leaks, etc. To make up for the low efficiency of traditional grid-type gas detection, gas infrared thermal imager devices have been widely used in fields such as petroleum, chemical industry, law enforcement patrols, etc.

[0003] The infrared detector of a refrigerated gas infrared thermal imager includes a refrigerator and a Dewar assembly. In the prior art, most linear refrigeration type infrared detectors adopt an I-shaped structure, that is, the refrigerator and the Dewar assembly are arranged parallel along the axis. The infrared thermal imager with this structure has the advantages of a compact structure and an overall short and wide shape. However, since the refrigerator itself emits a large amount of heat during operation, arranging the refrigerator parallel to the Dewar assembly is not conducive to the overall heat dissipation of the thermal imager. At the same time, the shutter of the infrared thermal imager is usually located at the connection between the infrared lens and the infrared detector, and the shutter is relatively close to the refrigerator. The heat of the refrigerator is extremely easy to transfer to the shutter, resulting in an excessively high temperature of the shutter and a problem of image quality deterioration. Summary of the Invention

[0004] Based on this, this application provides a refrigerated infrared detector and a thermal imager to improve the problems of poor heat dissipation caused by unreasonable arrangement of the refrigerator and image deterioration caused by temperature rise in the prior art.

[0005] To achieve the above object, the technical solution of the embodiment of this application is realized as follows:

[0006] On the one hand, the embodiment of this application provides a refrigerated infrared detector, including a Dewar assembly and a refrigerator. The refrigerator includes an expander and a compressor. The expander is coaxially connected to the Dewar assembly. The expander and the compressor are connected by a connecting pipe. The compressor is arranged on the side of the expander away from the Dewar assembly, and the axis of the compressor is perpendicular to the axis of the Dewar assembly.

[0007] In one embodiment, the refrigerated infrared detector further includes a vibration damping member, and the vibration damping member is arranged at one end of the compressor to reduce the vibration and noise of the refrigerator.

[0008] In one embodiment, the refrigerator is a linear Stirling refrigerator.

[0009] In one embodiment, the refrigerated infrared detector is a refrigerated gas infrared detector.

[0010] On the other hand, an embodiment of the present application provides a thermal imager, including the refrigerated infrared detector as described above.

[0011] In one embodiment, the thermal imager further includes a base, the Dewar assembly and the refrigerator are respectively fixed on the base, and the refrigerated infrared detector further includes a vibration damping member, and the vibration damping member is arranged at one end of the compressor away from the base.

[0012] In one embodiment, the thermal imager further includes a refrigerator drive module; the refrigerator drive module and the Dewar assembly are arranged side by side along the axial direction of the Dewar assembly, and an isolation plate is arranged between the refrigerator drive module and the Dewar assembly, and the isolation plate is used for heat insulation and preventing electromagnetic interference.

[0013] In one embodiment, the refrigerator drive module is arranged at the bottom of the Dewar assembly, a base is arranged below the refrigerator drive module, and an openable cover plate is arranged on the base.

[0014] In one embodiment, the thermal imager further includes a housing, the housing covers the base, and the housing and the base jointly form a space for accommodating the Dewar assembly and the refrigerator; the housing is respectively provided with heat dissipation structures at positions corresponding to the expander and the compressor.

[0015] In one embodiment, the thermal imager further includes an infrared lens and a shutter; the infrared lens is connected to the refrigerated infrared detector through a flange, and the Dewar assembly is arranged at one end close to the infrared lens, the compressor is arranged at one end away from the infrared lens, and the shutter is arranged in the flange.

[0016] In one embodiment, the flange is made of a low thermal conductivity material with a thermal conductivity ≤ 0.3 W / m·K.

[0017] In one embodiment, the flange is made of ABS or ABS plus polycarbonate material.

[0018] In one embodiment, the thermal imager further includes an imaging hardware module, and the imaging hardware module includes a power module, an image processing module and an analog-to-digital conversion module, and the power module, the image processing module, the analog-to-digital conversion module and the refrigerator drive module jointly surround the outer periphery of the Dewar assembly.

[0019] The present application has at least the following beneficial effects: In the refrigerated infrared detector according to the embodiment of the present application, the compressor and the expander are of a split design. The expander is connected to the Dewar assembly, and the compressor is arranged at one end of the expander away from the Dewar assembly, that is, the compressor, the expander, and the Dewar assembly are connected in sequence along the axis. There is no obstruction around the compressor, increasing the heat dissipation space. The axis of the compressor is perpendicular to the axis of the Dewar assembly, which can make the overall structure more compact while keeping the refrigerator in good heat dissipation conditions, facilitating the reduction of the overall volume of the refrigerated infrared detector and making it more portable. The refrigerator is arranged at one end of the Dewar assembly, which can increase the distance between the refrigerator and other components, facilitating the reduction of heat transfer, thereby improving the imaging quality of the thermal imager and avoiding image degradation. The thermal imager according to the embodiment of the present application includes the above-mentioned refrigerated infrared detector, and thus also has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic cross-sectional structure diagram of the thermal imager according to the embodiment of the present application.

[0021] Figure 2 is a schematic structural diagram of the refrigerated infrared detector according to the embodiment of the present application from one perspective.

[0022] Figure 3 is a schematic structural diagram of the refrigerated infrared detector according to the embodiment of the present application from another perspective.

[0023] Figure 4 is a schematic three-dimensional structure diagram of the thermal imager according to the embodiment of the present application.

[0024] Figure 5 is Figure 4 a schematic internal structure diagram of the thermal imager.

[0025] Figure 6 is a schematic layout structure diagram of the imaging hardware module according to the embodiment of the present application.

[0026] Figure 7 is a comparison diagram of the imaging quality of the thermal imager according to the embodiment of the present application and the imaging quality of a conventional thermal imager.

[0027] The meanings of the reference numerals in the drawings are as follows:

[0028] 1. Infrared lens; 2. Flange; 3. Housing; 31. Base; 311. Isolation plate; 312. Groove; 313. Cover plate; 32. Shell; 321. Heat dissipation structure; 4. Dewar assembly; 41. Exhaust pipe; 42. Detector signal module; 43. Ceramic lead ring; 44. Getter pin; 45. Mounting flange; 5. Refrigerator; 51. Expander; 52. Compressor; 53. Vibration damping member; 54. Connecting pipe; 541. Upper section; 542. Middle section; 543. Lower section; 6. Refrigerator drive module; 7. Imaging hardware module; 71. Power module; 72. Image processing module; 73. Analog-to-digital conversion module; 8. Shutter. Detailed implementation manners

[0029] The technical solution of the present application will be further elaborated in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used herein in the description of this application are only for the purpose of describing specific embodiments, and are not intended to limit the implementation manner of this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to this application. In the description of this application, unless otherwise stated, the meaning of "plurality" is two or more.

[0032] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

[0033] Please refer to Figures 1 to 3, the refrigerated infrared detector in the embodiment of the present application is a refrigerated gas infrared detector, including a Dewar assembly 4 and a refrigerator 5. The refrigerator 5 includes an expander 51 and a compressor 52. The expander 51 is coaxially connected to the Dewar assembly 4. The expander 51 and the compressor 52 are connected through a connecting pipe 54. The compressor 52 is arranged on the side of the expander 51 away from the Dewar assembly 4, and the axis of the compressor 52 is perpendicular to the axis of the Dewar assembly 4.

[0034] As Figure 2 and Figure 3 shown, the refrigerator 5 in this embodiment is preferably a linear Stirling refrigerator 5.

[0035] As Figure 4 shown, since the vibration and noise of the refrigerated infrared detector mainly come from the refrigerator 5, a vibration damping member 53 can be provided on the refrigerator 5 to reduce vibration and noise. In this embodiment, the vibration damping member 53 is arranged at one end of the compressor 52 away from the base 31, that is, the vibration damping member 53 is arranged on the top of the compressor 52.

[0036] The connecting pipe 54 in this embodiment is a copper pipe, and the connection points of the compressor 52 and the expander 51 are arranged as close as possible to reduce the overall length of the infrared detector. For example, the connection point of the expander 51 can be arranged on the side of the expander 51, the connection point of the compressor 52 can be arranged above the connection point of the expander 51, and the two connection points are close to each other and arranged on different planes. For example, the connecting pipe 54 can be bent into an upper section 541, a middle section 542, and a lower section 543. The upper section 541 and the lower section 543 are connected through the middle section 542. The lower section 543 is connected to the connection point of the expander 51, and the upper section 541 is connected to the connection point of the compressor 52. The upper section 541 and the lower section 543 are approximately on two parallel planes, and the middle section 542 is perpendicular to these two planes. The included angle between the upper section 541 and the axis of the Dewar assembly 4 can be set between 30° and 60°. This connection method can make the overall structure of the infrared detector more compact, and the compressor 52 and the Dewar assembly 4 are isolated from each other. The Dewar assembly 4 mainly includes an infrared optical window, a cold shield, and a detector chip, and its exterior includes an exhaust pipe 41, a ceramic lead ring 43, a getter pin 44, and a mounting flange 45, etc. The Dewar assembly 4 is a conventional product, and its specific structure will not be described in detail here.

[0037] As Figure 1 and Figure 5As shown in the figure, an embodiment of the present application further provides a thermal imager, which includes the above-mentioned refrigerated infrared detector, and further includes an infrared lens 1, a shutter 8, and a flange 2. The infrared lens 1 is connected to the refrigerated infrared detector through the flange 2, and the Dewar assembly 4 is arranged at one end close to the infrared lens 1, the compressor 52 is arranged at one end far from the infrared lens 1, the shutter 8 is arranged inside the flange 2, and the cryocooler drive module 6 is arranged side by side with the Dewar assembly 4 along the axial direction of the Dewar assembly 4. The compressor 52 is arranged on the side of the expander 51 far from the Dewar assembly 4, and the flange 2 is connected to one side of the Dewar assembly 4. This structure physically isolates the compressor 52 and the shutter 8 inside the flange 2. The compressor 52 and the flange 2 are far apart, and the heat generated by the compressor 52 is not easily transferred to the shutter 8, thereby avoiding excessive temperature rise of the shutter 8.

[0038] Specifically, as Figure 1 and Figure 3 shown in the figure, in this embodiment, it further includes a housing 3. The housing 3 includes a base 31 and a housing 32 covering the base 31. The base 31 and the housing 32 jointly enclose a space for accommodating the movement. The Dewar assembly 4 and the cryocooler 5 are respectively fixed on the base 31. To facilitate the heat dissipation of the cryocooler 5, the housing 3 can be made of a material with high thermal conductivity. For example, a material with a thermal conductivity ≥ 150 W / m·K can be used, such as a metal material. To further enhance the heat dissipation effect of the housing 3, heat dissipation structures 321 can be respectively arranged at the corresponding positions of the housing 32 and the expander 51 and the compressor 52. The heat dissipation structure 321 is mainly used to increase the surface area of the housing 3 to facilitate heat dissipation. For example, a number of fins or other heat dissipation structures 321 can be added to the outer wall of the housing 3, or the outer surface of the housing 3 can be set into regular or irregular concave and convex shapes. Specifically, the refrigerated infrared detector further includes a cryocooler drive module 6. The cryocooler drive module 6 is electrically connected to the cryocooler 5 and is used to drive the cryocooler 5. The flange 2 is connected between the infrared lens 1 and the housing 3. To avoid heat transfer between the shutter 8 and the cryocooler 5, the flange 2 can be made of a material with low thermal conductivity. The thermal conductivity of the flange 2 is lower than that of the detector housing 32. For example, the flange 2 can be made of a low thermal conductivity material with a thermal conductivity ≤ 0.3 W / m·K, such as ABS or ABS plus polycarbonate material. The low thermal conductivity flange 2 can prevent the heat generated by the cryocooler 5 from being transferred to the shutter 8 and causing the temperature of the shutter 8 to rise, thereby avoiding the problem of image quality deterioration. The housing 3 can be made of a material with high thermal conductivity. For example, the housing 3 can be made of a material with a thermal conductivity ≥ 150 W / m·K, such as metal, etc., which can accelerate the diffusion of the heat of the cryocooler 5.

[0039] To further reduce the heat conduction performance of the flange 2, a low-radiation structure (not shown) can also be provided on the inner surface of the flange 2. The low-radiation structure can be a concavo-convex structure provided on the inner surface of the flange 2, and the concavo-convex structure is used to increase the roughness of the inner surface of the flange 2; alternatively, the low-radiation structure can be a low-radiation coating provided on the inner surface of the flange 2, and the low-radiation coating is used to reduce the reflectivity of the inner surface of the flange 2. The low-radiation coating is achieved by coating a layer of material capable of reflecting or absorbing radiation on the substrate surface. These materials are usually metals or metal compounds, such as silver, copper, aluminum, titanium dioxide, etc. They can reflect a part of the radiation or convert it into other forms of energy, thereby reducing the exposure of the irradiated substance.

[0040] As Figure 1 shown, the refrigerator drive module 6 and the Dewar assembly 4 are arranged side by side, that is, the refrigerator drive module 6 is provided on one side of the Dewar assembly 4 to facilitate the maintenance, disassembly and assembly of the refrigerator drive module 6. To avoid interference between the refrigerator drive module 6 and the Dewar assembly 4, a partition plate 311 can be provided between the refrigerator drive module 6 and the Dewar assembly 4. The partition plate 311 can not only play a heat insulation role, but also avoid electromagnetic interference between the Dewar assembly 4 and the refrigerator drive module 6. In this embodiment, the refrigerator drive module 6 is provided at the bottom of the Dewar assembly 4, that is, on the side close to the base 31. The base 31 is provided with an openable cover plate 313. Opening the cover plate 313 can directly disassemble, assemble and maintain the drive module at the bottom. The cover plate 313 is detachably connected to the base 31, or the cover plate 313 is hinged to the base 31. The partition plate 311 can be provided separately or integrated with the base 31. For example, a groove 312 can be opened at the bottom of the base 31, and the groove 312 is used to place the refrigerator drive module 6. The cover plate 313 covers the groove 312. This structure can enclose the refrigerator drive module 6 in a sealed cavity, isolate it from the Dewar assembly 4 to the greatest extent, and can more effectively prevent heat transfer and electromagnetic interference between the refrigerator drive module 6 and the Dewar assembly 4.

[0041] As Figure 1 and Figure 6As shown in the figure, the thermal imager of this embodiment further includes an imaging hardware module 7, and the imaging hardware module 7 includes a power supply module 71, an image processing module 72, and an analog-to-digital conversion module 73. The power supply module 71, the image processing module 72, the analog-to-digital conversion module 73, and the cooler driving module 6 are jointly arranged around the outer periphery of the Dewar assembly 4. In this embodiment, each circuit board assembly that is usually integrally designed is modularly decomposed and arranged around the Dewar assembly 4. Each module occupies one side of the Dewar assembly 4. This design not only makes full use of the space and is beneficial to reducing the overall volume of the thermal imager, but also is conducive to the heat dissipation of each module, thereby improving the performance of the entire thermal imager and the image output quality. The Dewar assembly 4 further includes a detector signal module 42, and the detector signal module 42 is respectively signal-connected to the ceramic lead ring 43, the image processing module 72, the analog-to-digital conversion module 73, and the cooler driving module 6, and is used to supply power to the infrared detector, provide a driving signal for the infrared detector, and transmit the output signal of the infrared detector. The analog-to-digital conversion module 73 is signal-connected to the image processing module 72, and is used to receive the analog output signal of the infrared detector, convert it into a digital signal, and then transmit it to the image processing module 72. The image processing module 72 of this embodiment is an FPGA image processing module 72, which is electrically connected to the power supply module 71, and is used to receive the digital signal transmitted by the analog-to-digital conversion module 73, convert it into an image and output it. At the same time, it is also used to provide a driving signal for the infrared detector, and as the main control component of the thermal imager, it realizes functions such as controlling the movement mechanism. The power supply module 71 is respectively electrically connected to the image processing module 72 and the detector signal module 42, and is used to supply power to the thermal imager and realize the movement mechanism control serial port and video interface. The cooler driving module 6 is used to supply power to the cooler 5 and perform temperature feedback of the cooler 5.

[0042] For the cooled infrared detector and thermal imager of the embodiments of the present application, the structure design of its movement mechanism is more reasonable, which is beneficial to the heat dissipation of the cooler itself, physically isolates the cooler and the shutter, and reduces the heat transfer between the cooler and the shutter. At the same time, the flange is made of a material with low thermal conductivity, which further reduces the influence of the cooler on the shutter temperature. After testing, compared with the infrared thermal imager with a conventional structure, for the thermal imager with the structure of the embodiments of the present application, the temperature rise of its shutter drops by about 8 °C, and the image quality is significantly improved. As Figure 7 shown, in the left figure A is the gas detection image presented by a conventional thermal imager, and the right figure is the gas detection image presented by the thermal imager of the embodiments of the present application. On the basis of enhancing the heat dissipation function, the infrared detector of the embodiments of the present application also takes into account the compact layout of the overall structure. By setting a heat dissipation structure on the housing, the heat dissipation performance of the expander and the compressor can be further enhanced, and it is avoided that their temperatures are too high and affect other components.

[0043] It should be noted that in this text, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising such element.

[0044] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A refrigerated infrared detector, comprising a Dewar assembly (4) and a refrigerator (5), characterized in that: The refrigerator (5) comprises an expander (51) and a compressor (52); the expander (51) and the Dewar assembly (4) are coaxially connected; the expander (51) and the compressor (52) are connected via a connecting pipe (54); the compressor (52) is arranged on a side of the expander (51) away from the Dewar assembly (4); and the axis of the compressor (52) and the axis of the Dewar assembly (4) are arranged perpendicularly.

2. The refrigerated infrared detector according to claim 1, characterized in that: It also includes a vibration damping member (53), which is arranged at one end of the compressor (52) and is used to reduce the vibration and noise of the refrigerator (5).

3. The refrigerated infrared detector according to claim 1, characterized in that: The refrigerator (5) is a linear Stirling refrigerator.

4. The refrigerated infrared detector according to claim 1, characterized in that: The refrigerated infrared detector is a refrigerated gas infrared detector.

5. A thermal imager, characterized in that: It comprises a refrigerated infrared detector as described in any one of claims 1 to 4.

6. The thermal imager according to claim 5, characterized in that: The invention also comprises a base (31), the Dewar assembly (4) and the refrigerator (5) are respectively fixed on the base (31), and the refrigeration-type infrared detector further comprises a vibration damping member (53), and the vibration damping member (53) is arranged at one end of the compressor (52) away from the base (31).

7. The thermal imager according to claim 5, characterized in that: It also comprises a refrigerator drive module (6); the refrigerator drive module (6) and the Dewar assembly (4) are arranged in parallel along the axial direction of the Dewar assembly (4); an isolation plate (311) is provided between the refrigerator drive module (6) and the Dewar assembly (4); the isolation plate (311) is used for heat insulation and preventing electromagnetic interference.

8. The thermal imager according to claim 7, characterized in that: The refrigerator drive module (6) is arranged at the bottom of the Dewar assembly (4), a base (31) is arranged below the refrigerator drive module (6), and an openable cover plate (313) is arranged on the base (31).

9. The thermal imager according to claim 6, characterized in that: The invention also comprises a shell (32), wherein the shell (32) is covered on the base (31), and the shell (32) and the base (31) together form a space for accommodating the Dewar assembly (4) and the refrigerator (5); the shell (32) is provided with heat dissipation structures (321) at corresponding positions of the expander (51) and the compressor (52).

10. The thermal imager according to claim 5, characterized in that: It also includes an infrared lens (1) and a shutter (8); the infrared lens (1) is connected to the refrigerated infrared detector via a flange (2), the Dewar assembly (4) is arranged at an end close to the infrared lens (1), the compressor (52) is arranged at an end away from the infrared lens (1), and the shutter (8) is arranged in the flange (2).

11. The thermal imager according to claim 10, characterized in that: The flange (2) is made of a low thermal conductivity material with a thermal conductivity of ≤0.3 W / m·K.

12. The thermal imager according to claim 11, characterized in that: The flange (2) is made of ABS or ABS plus polycarbonate material.

13. The thermal imager according to claim 7 or 8, characterized in that: The system also includes an imaging hardware module (7), wherein the imaging hardware module (7) includes a power module (71), an image processing module (72), and an analog-to-digital conversion module (73), wherein the power module (71), the image processing module (72), the analog-to-digital conversion module (73), and the refrigerator drive module (6) are arranged together on the periphery of the Dewar assembly (4).

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