Refrigeration-type infrared detector and thermal imaging camera

Abstract

A refrigeration-type infrared detector and a thermal imaging camera. The refrigeration-type infrared detector comprises a Dewar assembly (4) and a refrigerator (5). 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 communicated by means of a connecting pipe (54). The compressor (52) is arranged on the side of the expander (51) far from the Dewar assembly (4), and the axis of the compressor (52) is arranged perpendicular to the axis of the Dewar assembly (4). The refrigeration-type infrared detector and thermal imaging camera have appropriate structural layout, so that the heat dissipation effect of the refrigerator is enhanced and image deterioration caused by temperature rise of a shutter can be effectively alleviated.

Description

Refrigeration type infrared detector and thermal imager TECHNICAL FIELD

[0001] The present application relates to the technical field of infrared detection equipment, in particular to a refrigeration type infrared detector and a thermal imager. BACKGROUND

[0002] A gas infrared thermal imager is an imaging device that realizes visualization by photoelectric conversion of infrared radiation of a target object using infrared thermal imaging technology. It can visualize invisible gas and can be used for detecting gas leakage. In order to make up for the low efficiency of traditional net format gas detection, the gas infrared thermal imager has been widely used in the fields of petroleum, chemical industry, law enforcement and inspection.

[0003] The infrared detector of the refrigeration type gas infrared thermal imager includes a refrigerator and a Dewar assembly. In the prior art, the refrigeration type infrared detector is usually in the shape of a capital letter I, that is, the refrigerator and the Dewar assembly are arranged in parallel along the axial direction. The infrared thermal imager with this structure has the advantages of compact structure and short and wide overall shape. However, since the refrigerator itself generates a large amount of heat during operation, the parallel arrangement of the refrigerator and the Dewar assembly is not conducive to the heat dissipation of the thermal imager as a whole. Meanwhile, the shutter of the infrared thermal imager is usually arranged at the connection between the infrared lens and the infrared detector. Since the shutter is close to the refrigerator, the heat of the refrigerator is easily transferred to the shutter, resulting in high temperature of the shutter and image quality degradation. SUMMARY

[0004] Therefore, the present application provides a refrigeration type infrared detector and a thermal imager to solve the problems of poor heat dissipation caused by unreasonable arrangement of the refrigerator and image degradation caused by temperature rise in the prior art.

[0005] To achieve the above-mentioned purpose, the technical scheme of the embodiments of the present application is as follows:

[0006] In one aspect, the present application provides a refrigeration type infrared detector, which includes a Dewar assembly and a refrigerator. The refrigerator includes an expander and a compressor. The expander and the Dewar assembly are coaxially connected. The expander and the compressor are communicated through a connecting pipe. The compressor is arranged on the side of the expander away from the Dewar assembly, and the axis of the compressor and the axis of the Dewar assembly are arranged perpendicularly.

[0007] In one of the embodiments, the refrigeration type infrared detector further includes a damping member arranged at one end of the compressor for reducing the vibration and noise of the refrigerator.

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

[0009] In one of the embodiments, the refrigeration-type infrared detector is a refrigeration-type gas infrared detector.

[0010] In another aspect, the embodiments of the present application provide a thermal imager, comprising the refrigeration-type infrared detector as described above.

[0011] In one of the embodiments, the thermal imager further comprises a base, the dewar assembly and the refrigerator are fixed on the base respectively, the refrigeration-type infrared detector further comprises a damping member, the damping member is arranged at the end of the compressor away from the base.

[0012] In one of the embodiments, the thermal imager further comprises a refrigerator driving module; the refrigerator driving module and the dewar assembly are arranged along the axial direction of the dewar assembly, and a separation plate is arranged between the refrigerator driving module and the dewar assembly, the separation plate is used for heat insulation and electromagnetic interference prevention.

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

[0014] In one of the embodiments, the thermal imager further comprises a shell, the shell is arranged on the base, and the shell and the base jointly form a space for accommodating the dewar assembly and the refrigerator; the shell is provided with a heat dissipation structure at the positions corresponding to the expander and the compressor respectively.

[0015] In one of the embodiments, the thermal imager further comprises an infrared lens and a shutter; the infrared lens is connected with the refrigeration-type infrared detector through a flange, the dewar assembly is arranged at the end close to the infrared lens, the compressor is arranged at the end away from the infrared lens, and the shutter is arranged in the flange.

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

[0017] In one of the embodiments, the flange is made of ABS or ABS plus poly carbon material.

[0018] In one of the embodiments, the thermal imager further comprises an imaging hardware module, the imaging hardware module comprises a power module, an image processing module and an analog-digital conversion module, and the power module, the image processing module, the analog-digital conversion module and the refrigerator driving module are jointly arranged at the periphery of the dewar assembly.

[0019] The refrigeration type infrared detector of the embodiment of the present application has the following beneficial effects: the compressor and the expander of the refrigeration type infrared detector are designed in a split type, the expander is connected with the Dewar assembly, the compressor is arranged at the end of the expander away from the Dewar assembly, that is, the compressor, the expander and the Dewar assembly are sequentially arranged along the axial direction, the compressor is not circumferentially blocked, and the heat dissipation space is increased. The axis of the compressor is arranged perpendicularly to the axis of the Dewar assembly, the overall structure is more compact under the condition that the refrigeration machine maintains good heat dissipation conditions, which is conducive to reducing the overall volume of the refrigeration type infrared detector and making it more portable. The refrigeration machine is arranged at one end of the Dewar assembly, the distance between the refrigeration machine and other components is increased, which is conducive to reducing heat transfer and thus improving the imaging quality of the thermal imager and avoiding image degradation. The thermal imager of the embodiment of the present application comprises the above refrigeration type infrared detector, and thus also has the above beneficial effects. BRIEF DESCRIPTION OF DRAWINGS

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

[0021] Fig. 2 is a schematic diagram of the structure of the refrigeration type infrared detector of the embodiment of the present application from one perspective.

[0022] Fig. 3 is a schematic diagram of the structure of the refrigeration type infrared detector of the embodiment of the present application from another perspective.

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

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

[0025] Fig. 6 is a schematic diagram of the arrangement structure of the imaging hardware module of the embodiment of the present application.

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

[0027] The meanings of the reference numbers in the drawings are as follows: 1, infrared lens; 2, flange; 3, shell; 31, base; 311, isolation plate; 312, groove; 313, cover plate; 32, housing; 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, refrigeration machine; 51, expander; 52, compressor; 53, damping member; 54, connecting pipe; 541, upper section; 542, middle section; 543, lower section; 6, refrigeration machine driving module; 7, imaging hardware module; 71, power supply module; 72, image processing module; 73, analog-to-digital conversion module; 8, shutter. DETAILED DESCRIPTION

[0028] The technical solutions of the present application are further described in detail below in combination with the drawings and specific embodiments of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of implementations of the present application. As used in this description, the terms "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not 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 a limitation on the present application. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0031] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication between the 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.

[0032] Please refer to FIG. 1 to FIG. 3, the refrigeration type infrared detector of the embodiment of the present application is a refrigeration type gas infrared detector, which comprises a dewar assembly 4 and a refrigerator 5, 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 communicated 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 and the axis of the dewar assembly 4 are arranged vertically.

[0033] As shown in FIG. 2 and FIG. 3, the refrigerator 5 in the embodiment is preferably a linear Stirling refrigerator 5.

[0034] As shown in FIG. 4, since the vibration and noise of the refrigeration type infrared detector mainly come from the refrigerator 5, in order to reduce the vibration and noise, a damping member 53 can be arranged on the refrigerator 5, and the damping member 53 in the embodiment is arranged on the end of the compressor 52 away from the base 31, that is, the damping member 53 is arranged on the top of the compressor 52.

[0035] The connecting pipe 54 in the embodiment is a copper pipe, and the connecting 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 connecting point of the expander 51 can be arranged on the side of the expander 51, and the connecting point of the compressor 52 can be arranged above the connecting point of the expander 51. The two connecting points are arranged close to each other and on different surfaces. 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 with the connecting point of the expander 51, and the upper section 541 is connected with the connecting point of the compressor 52. The upper section 541 and the lower section 543 are approximately arranged on two parallel planes, and the middle section 542 is arranged perpendicularly to the two planes. The angle between the upper section 541 and the axis of the Dewar assembly 4 can be arranged between 30° and 60°. This connection mode can make the overall structure of the infrared detector more compact, and the compressor 52 and the Dewar assembly 4 are arranged to be isolated from each other. The Dewar assembly 4 mainly includes an infrared optical window, a cold shield and a detector chip. The outside of the Dewar assembly 4 includes an exhaust pipe 41, a ceramic lead ring 43, a getter pin 44 and a mounting flange 45. The Dewar assembly 4 is a conventional product, and its specific structure will not be described here.

[0036] As shown in FIG. 1 and FIG. 5, the embodiment of the present application also provides a thermal imager, which includes the above-mentioned refrigeration-type infrared detector, and further includes an infrared lens 1, a shutter 8 and a flange 2. The infrared lens 1 is connected with the refrigeration-type infrared detector through the flange 2. The Dewar assembly 4 is arranged at one end close to the infrared lens 1, and the compressor 52 is arranged at one end away from the infrared lens 1. The shutter 8 is arranged in the flange 2. The refrigeration machine driving module 6 and the Dewar assembly 4 are arranged in parallel along the axis of the Dewar assembly 4. The compressor 52 is arranged on the side of the expander 51 away from the Dewar assembly 4, and the flange 2 is connected to one side of the Dewar assembly 4. This structure realizes physical isolation between the compressor 52 and the shutter 8 inside the flange 2. The compressor 52 and the flange 2 are far away from each other, and the heat generated by the compressor 52 is not easily transmitted to the shutter 8, thereby avoiding excessive temperature rise of the shutter 8.

[0037] Specifically, as shown in FIG. 1 and FIG. 3, in the embodiment, the housing 3 is further included, the housing 3 includes a base 31 and a shell 32 covering the base 31, and the base 31 and the shell 32 jointly enclose a space for accommodating the movement. The Dewar assembly 4 and the refrigerator 5 are respectively fixed on the base 31, in order to facilitate heat dissipation of the refrigerator 5, the housing 3 can be made of a high thermal conductivity material, for example, a material with a thermal conductivity ≥ 150 W / m·K, such as a metal material. In order to further increase the heat dissipation effect of the housing 3, a heat dissipation structure 321 can be arranged at the corresponding position of the shell 32 and the expander 51 and the compressor 52 respectively, and the heat dissipation structure 321 is mainly used to increase the surface area of the shell 32 to facilitate heat dissipation, for example, a plurality of fins or other heat dissipation structures 321 can be added to the outer wall of the shell 32, or the outer surface of the shell 32 is arranged in a regular or irregular concave-convex shape. Specifically, the refrigeration type infrared detector further includes a refrigerator driving module 6, the refrigerator driving module 6 and the refrigerator 5 are electrically connected, and the refrigerator driving module 6 is used to drive the refrigerator 5. The flange 2 is connected between the infrared lens 1 and the housing 3. In order to avoid heat transfer between the shutter 8 and the refrigerator 5, the flange 2 can be made of a low thermal conductivity material, and the thermal conductivity of the flange 2 is lower than that of the detector shell 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 carbon material. The low thermal conductivity flange 2 can avoid the heat generated by the refrigerator 5 from being transferred to the shutter 8 to increase the temperature of the shutter 8, thereby avoiding the problem of image quality degradation. The housing 3 can be made of a high thermal conductivity material, for example, the housing 3 can be made of a material with a thermal conductivity ≥ 150 W / m·K, such as metal, which can accelerate the diffusion of heat of the refrigerator 5.

[0038] In order to further reduce the thermal conductivity of the flange 2, a low-emission structure (not shown) can also be arranged on the inner surface of the flange 2. The low-emission structure can be a concave-convex structure arranged on the inner surface of the flange 2, which is used to increase the roughness of the inner surface of the flange 2; or the low-emission structure can be a low-emission coating arranged on the inner surface of the flange 2, which is used to reduce the reflectivity of the inner surface of the flange 2, and the low-emission coating is realized by coating a layer of material capable of reflecting or absorbing radiation on the surface of the substrate. These materials are usually metals or metal compounds, such as silver, copper, aluminum, titanium dioxide, etc. They can reflect part of the radiation or convert it into other forms of energy, thereby reducing the heat transfer from the inside of the flange 2 to the outside.

[0039] As shown in FIG. 1, the refrigerator driving module 6 is arranged side by side with the dewar assembly 4, that is, the refrigerator driving module 6 is arranged at one side of the dewar assembly 4 to facilitate the maintenance and disassembly of the refrigerator driving module 6. In order to avoid interference between the refrigerator driving module 6 and the dewar assembly 4, an isolation plate 311 can be arranged between the refrigerator driving module 6 and the dewar assembly 4. The isolation plate 311 can not only play a heat insulation role, but also avoid electromagnetic interference between the dewar assembly 4 and the refrigerator driving module 6. In the embodiment, the refrigerator driving module 6 is arranged at the bottom of the dewar assembly 4, that is, close to one side of the base 31. The base 31 is provided with an openable cover plate 313. The cover plate 313 can be opened to directly disassemble and maintain the driving module at the bottom. The cover plate 313 is detachably connected with the base 31, or the cover plate 313 is hinged with the base 31. The isolation plate 311 can be separately arranged or integrated with the base 31. For example, a groove 312 can be formed at the bottom of the base 31. The groove 312 is used to place the refrigerator driving module 6. The cover plate 313 is arranged on the groove 312. This structure can make the refrigerator driving module 6 closed in a sealed cavity, which maximally isolates the dewar assembly 4, and can more effectively prevent heat transfer and electromagnetic interference between the refrigerator driving module 6 and the dewar assembly 4.

[0040] As shown in FIG. 1 and FIG. 6, the thermal imager of the embodiment further comprises an imaging hardware module 7, which comprises a power module 71, an image processing module 72 and an analog-digital conversion module 73. The power module 71, the image processing module 72, the analog-digital conversion module 73 and the refrigerator driving module 6 are collectively enclosed in the periphery of the Dewar assembly 4. The embodiment modularly decomposes each circuit board assembly that is usually integrated into an integral structure, and arranges them around the Dewar assembly 4, each module occupying one side of the Dewar assembly 4. This design not only makes full use of the space, but also helps to reduce the overall volume of the thermal imager, and at the same time, helps to dissipate heat of each module, thereby improving the performance of the thermal imager and the quality of image output. The Dewar assembly 4 further comprises a detector signal module 42, which is respectively connected in signal with the ceramic lead ring 43, the image processing module 72, the analog-digital conversion module 73 and the refrigerator driving module 6, for supplying power to the infrared detector, providing a driving signal for the infrared detector and transmitting an output signal of the infrared detector. The analog-digital conversion module 73 is connected in signal with the image processing module 72, for receiving an analog output signal of the infrared detector and transmitting it to the image processing module 72 after converting it into a digital signal. The image processing module 72 of the embodiment is an FPGA image processing module, which is electrically connected with the power module 71, for receiving the digital signal transmitted by the analog-digital conversion module 73, converting it into an image and outputting it, and at the same time, for providing a driving signal for the infrared detector, as the main control component of the thermal imager, to realize the control of the movement of the shutter and other functions. The power module 71 is electrically connected with the image processing module 72 and the detector signal module 42, for supplying power to the thermal imager, and setting a movement control serial port and a video interface. The refrigerator driving module 6 is for supplying power to the refrigerator 5 and feeding back the temperature of the refrigerator 5.

[0041] The refrigerator-type infrared detector and the thermal imager of the embodiment have a more reasonable movement structure, which is beneficial to heat dissipation of the refrigerator itself, and makes the refrigerator and the shutter physically isolated, thereby reducing the heat transfer between the refrigerator and the shutter. At the same time, the flange is made of a low-thermal-conductivity material, which further reduces the influence of the refrigerator on the temperature of the shutter. After detection, compared with the conventional infrared thermal imager, the thermal imager of the embodiment has a shutter temperature rise of about 8℃, and the image quality is obviously improved. As shown in FIG. 7, the left image A is a gas detection image of the conventional thermal imager, and the right image is a gas detection image of the thermal imager of the embodiment. The infrared detector of the embodiment not only enhances the heat dissipation function, but also takes into account the compact layout of the overall structure. By arranging the heat dissipation structure on the shell, the heat dissipation performance of the expander and the compressor can be further enhanced, thereby avoiding the influence of high temperature on other components.

[0042] It should be noted that, as used in this document, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a", "comprising", or "comprises" does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0043] The above description is only specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A cryogenically cooled 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 communicated 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) and the axis of the dewar assembly (4) are arranged vertically.

2. The cryogenic infrared detector of claim 1, wherein, Further comprising a damping member (53), the damping member (53) is arranged on one end of the compressor (52), and is used for reducing the vibration and noise of the refrigerator (5).

3. The cryogenic infrared detector of claim 1, wherein, The refrigerator (5) is a linear Stirling refrigerator.

4. The cryogenic infrared detector of claim 1, wherein, The refrigerator-type infrared detector is a refrigerator-type gas infrared detector.

5. A thermal imager, characterized in that The refrigerator-type infrared detector comprises the dewar assembly (4) and the refrigerator (5) as claimed in any one of claims 1 to 4.

6. The thermal imager of claim 5 wherein, Further comprising a base (31), the dewar assembly (4) and the refrigerator (5) are fixed on the base (31) respectively, and the refrigerator-type infrared detector further comprises a damping member (53), the damping member (53) is arranged on one end of the compressor (52) away from the base (31).

7. The thermal imager of claim 5 wherein, Further comprising a refrigerator driving module (6), the refrigerator driving module (6) and the dewar assembly (4) are arranged side by side along the axial direction of the dewar assembly (4), and an isolation plate (311) is arranged between the refrigerator driving module (6) and the dewar assembly (4), the isolation plate (311) is used for heat insulation and preventing electromagnetic interference.

8. The thermal imager of claim 7 wherein, The refrigerator driving module (6) is arranged at the bottom of the dewar assembly (4), a base (31) is arranged below the refrigerator driving module (6), and an openable cover plate (313) is arranged on the base (31).

9. The thermal imager of claim 6 wherein, Further comprising a shell (32), the shell (32) is arranged on the base (31), and the shell (32) and the base (31) jointly form a space for accommodating the dewar assembly (4) and the refrigerator (5); and the shell (32) is provided with a heat dissipation structure (321) at the positions corresponding to the expander (51) and the compressor (52) respectively.

10. The thermal imager of claim 5 wherein, Further comprising an infrared lens (1) and a shutter (8), the infrared lens (1) is connected with the refrigerator-type infrared detector through a flange (2), the dewar assembly (4) is arranged at one end close to the infrared lens (1), the compressor (52) is arranged at one end away from the infrared lens (1), and the shutter (8) is arranged in the flange (2).

11. The thermal imager of claim 10 wherein, 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 of claim 11 wherein, The flange (2) is made of ABS or ABS plus poly carbon material.

13. The thermal imager of claim 7 or 8, wherein, Further comprising an imaging hardware module (7), the imaging hardware module (7) comprises a power supply module (71), an image processing module (72) and an analog-to-digital conversion module (73), and the power supply module (71), the image processing module (72), the analog-to-digital conversion module (73) and the refrigerator driving module (6) are jointly arranged around the periphery of the dewar assembly (4).

Images