Low-temperature infrared radiation detection equipment

Abstract

The invention relates to the technical field of low-temperature infrared radiation detection, and provides low-temperature infrared radiation detection equipment, which comprises a vacuum cold box, an infrared detection device, a control system and a signal processing system, and is characterized in that the infrared detection device comprises an infrared window sheet, an optical shutter, an optical lens, an optical chopper and an infrared detector; the optical chopper adjusts an infrared radiation signal emitted by a target object to a predetermined frequency, and the infrared detector receives the infrared radiation signal and converts the infrared radiation signal into an electric signal; the signal processing system comprises a pre-amplifier, a lock-in amplifier, a signal processing unit and a display unit, the pre-amplifier amplifies the electric signals output by the infrared detector, and the lock-in amplifier extracts signals corresponding to the preset frequency from the electric signals amplified by the pre-amplifier and amplifies the signals. Through the arrangement, the optical chopper, the pre-amplifier and the lock-in amplifier are combined, so that the measurement precision of infrared detection is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cryogenic infrared radiation detection, and in particular, to a cryogenic infrared radiation detection device. Background Art

[0002] Modern thermal diagnosis mainly relies on infrared thermal imaging technology, which generates a temperature distribution image by capturing the infrared radiation emitted by a target object. This method can measure the surface temperature of the target object without contacting it. In some fields, modern thermal diagnosis has put forward high-precision requirements for low-temperature thermal field measurement, such as cryoablation of pathological tissues and cryopreservation of biological tissues in the field of cryomedicine. Among them, cryomedical devices usually use liquid nitrogen cooling to reduce the tissue temperature to -150°C, while cryoablation of malignant tumors requires the temperature to be controlled within the range of -40°C to -60°C. To ensure the treatment effect and prevent tissue damage, it is crucial to monitor the temperature change during cryotherapy in real time and non-invasively.

[0003] In the related art, an infrared thermal imager is generally used for low-temperature thermal field measurement. However, due to the extremely low radiation flux of low-temperature objects, the signal intensity is equivalent to the thermal radiation of the optical elements of the infrared thermal imager, resulting in a serious impact on the measurement accuracy of the infrared thermal imager.

[0004] Therefore, providing a cryogenic infrared detection device with high measurement accuracy is an important issue that the industry urgently needs to solve at present. Summary of the Invention

[0005] The present invention provides a cryogenic infrared radiation detection device to improve the accuracy of low-temperature thermal field measurement.

[0006] The present invention provides a cryogenic infrared radiation detection device, including: A vacuum cold box, with an observation port provided on the side wall of the vacuum cold box; An infrared detection device, including an infrared window sheet, an optical shutter, an optical lens, an optical chopper, and an infrared detector arranged in sequence. The infrared window sheet is arranged at the observation port, the infrared detector is arranged inside the vacuum cold box, the optical shutter, the optical lens, and the optical chopper are sequentially arranged between the infrared window sheet and the infrared detector. The optical chopper is adapted to adjust the infrared radiation signal emitted by the target object to a predetermined frequency, and the infrared detector is adapted to receive the infrared radiation signal and convert it into an electrical signal; A control system, where both the optical shutter and the optical chopper are electrically connected to the control system; A signal processing system, comprising a preamplifier, a lock-in amplifier, a signal processing unit, and a display unit that are electrically connected in sequence. The preamplifier is electrically connected to the infrared detector. The preamplifier is adapted to amplify the electrical signal output by the infrared detector. The lock-in amplifier is adapted to extract and amplify the signal corresponding to a predetermined frequency from the electrical signal amplified by the preamplifier. The signal processing unit is adapted to receive the signal output by the lock-in amplifier, analyze and process it, and output the result to the display unit.

[0007] A cryogenic infrared radiation detection device provided according to the present invention, wherein the optical shutter comprises: A first support frame, the lower end of the first support frame being supported on the bottom wall of the vacuum cold box; A first disk body, rotatably arranged on the upper end of the first support frame. The first disk body has a first black body portion, a second black body portion, and a first hollow portion distributed along its circumferential direction; A first temperature sensor, arranged on the first black body portion and the second black body portion. The first temperature sensor is arranged on the side of the first disk body away from the infrared detector; An infrared reflector, arranged overlapping with the second black body portion. The infrared reflector is arranged on the side of the first disk body close to the infrared detector; A first driving motor, arranged on the first support frame. The first driving motor is adapted to drive the first disk body to rotate relative to the first support frame. The first driving motor is electrically connected to the control system.

[0008] A cryogenic infrared radiation detection device provided according to the present invention, wherein the first disk body is circular, and the first black body portion, the second black body portion, and the first hollow portion are all fan-shaped, and the central angles corresponding to the fan shapes are all 120 degrees.

[0009] A cryogenic infrared radiation detection device provided according to the present invention further comprises: A position adjusting device, arranged between the infrared detector and the vacuum cold box. The position adjusting device is adapted to adjust the position of the infrared detector along the distribution direction of the optical shutter and the optical lens.

[0010] A cryogenic infrared radiation detection device provided according to the present invention, wherein the position adjusting device comprises: A third support frame, the lower end of the third support frame being supported on the bottom wall of the vacuum cold box; A slide rail mechanism, comprising a guide rail and a sliding seat slidably connected to the guide rail. The axis of the guide rail is parallel to the distribution direction of the optical shutter and the optical lens. The infrared detector is arranged on the sliding seat; A driving mechanism, adapted to drive the sliding seat to reciprocate relative to the guide rail, and the driving mechanism is electrically connected to a control system.

[0011] A cryogenic infrared radiation detection device according to the present invention, the driving mechanism includes: A roller, rotatably arranged on the sliding seat around its own axis, and the roller is adapted to roll along the slide rail mechanism; A third driving motor, adapted to drive the roller to rotate relative to the sliding seat, and the third driving motor is electrically connected to the control system.

[0012] A cryogenic infrared radiation detection device according to the present invention, the optical lens includes: A fourth support frame, the lower end of the fourth support frame is supported on the bottom wall of the vacuum cold box, and the upper end of the fourth support frame is provided with a mounting frame, and the mounting frame is circular; A convex lens, arranged in the mounting frame, and the convex lens is adapted to focus infrared radiation signals, and the thermal expansion coefficient of the convex lens is the same as that of the mounting frame; A fixing member, adapted to fix the convex lens to the mounting frame, and a plurality of fixing members are provided, and the plurality of fixing members are evenly distributed along the circumferential direction of the mounting frame.

[0013] A cryogenic infrared radiation detection device according to the present invention, the optical chopper includes: A second support frame, the lower end of the second support frame is supported on the bottom wall of the vacuum cold box; A second disc, rotatably arranged on the upper end of the second support frame, and the second disc has a third black body part and a second hollow part spaced apart along its own circumferential direction; A second driving motor, arranged on the second support frame, and the second driving motor is adapted to drive the second disc to rotate relative to the second support frame, and the second driving motor is electrically connected to the control system.

[0014] A cryogenic infrared radiation detection device according to the present invention, the infrared detector is one of a mercury cadmium telluride liquid nitrogen cooling type detector and a thermoelectric cooling type detector.

[0015] A cryogenic infrared radiation detection device according to the present invention further includes: A temperature regulating device is adapted to regulate the temperatures of the infrared detector and inside the vacuum cold box within a preset range. The temperature regulating device includes a heater, a radiation plate, a refrigerator, and a second temperature sensor. The heater and the radiation plate are disposed inside the vacuum cold box, the second temperature sensor is disposed on the radiation plate. The infrared detector has a heat exchange shell through which liquid nitrogen can flow, and the radiation plate has a heat exchange cavity inside for liquid nitrogen to flow through. The refrigerator, the heat exchange shell, the heater, and the radiation plate are connected to form a closed loop. The heater, the second temperature sensor, and the refrigerator are all electrically connected to the control system.

[0016] For a low-temperature infrared radiation detection device provided by the present invention, a polished aluminum layer is disposed on the outside of the radiation plate and the outside of the heater.

[0017] The low-temperature infrared radiation detection device provided by the present invention includes a vacuum cold box, an infrared detection device, a control system, and a signal processing system. The vacuum cold box is used to provide a vacuum and low-temperature environment. The infrared detection device includes an infrared window sheet, an optical shutter, an optical lens, an optical chopper, and an infrared detector which are arranged in sequence. An observation port is provided on the side wall of the vacuum cold box, the infrared window sheet is disposed at the observation port, and the infrared window sheet can transmit infrared radiation signals. The infrared detector is disposed inside the vacuum cold box, and the optical shutter, the optical lens, and the optical chopper are sequentially disposed between the infrared window sheet and the infrared detector to ensure that the infrared radiation signals of a target object located outside the observation port enter the vacuum cold box and sequentially pass through the optical shutter, the optical lens, the optical chopper, and the infrared detector. Both the optical shutter and the optical chopper are electrically connected to the control system. The optical chopper is used to adjust the infrared radiation signals emitted by the target object to a predetermined frequency to improve the signal-to-noise ratio. The infrared detector is used to receive the infrared radiation signals and convert them into electrical signals. The signal processing system includes a preamplifier, a lock-in amplifier, a signal processing unit, and a display unit which are electrically connected in sequence. The preamplifier is electrically connected to the infrared detector, and the preamplifier can amplify the electrical signals output by the infrared detector. The lock-in amplifier is used to extract and amplify the signals corresponding to the predetermined frequency from the electrical signals amplified by the preamplifier to enhance the signal intensity. The signal processing unit receives the amplified and enhanced signals, analyzes and processes them, and outputs the results to the display unit. With such an arrangement, in combination with the optical chopper, the preamplifier, and the lock-in amplifier, the measurement accuracy of infrared detection is effectively improved. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of the low-temperature infrared radiation detection device provided by the present invention.

[0020] Figure 2 It is a schematic structural diagram of one side of the optical shutter close to the infrared detector provided by the present invention.

[0021] Figure 3 It is a schematic structural diagram of one side of the optical shutter far from the infrared detector provided by the present invention.

[0022] Figure 4 It is a schematic structural diagram of the optical lens provided by the present invention.

[0023] Figure 5 It is a schematic structural diagram of the optical chopper provided by the present invention.

[0024] Figure 6 It is a schematic structural diagram of the position adjustment device provided by the present invention.

[0025] Reference numerals: 1. Vacuum cold box; 2. Infrared window piece; 3. Optical shutter; 4. Optical lens; 5. Optical chopper; 6. Infrared detector; 7. Control system; 8. Preamplifier; 9. Phase-locked amplifier; 10. Signal processing unit; 11. Display unit; 12. First support frame; 13. First disk body; 14. First black body part; 15. Second black body part; 16. First hollow part; 17. First temperature sensor; 18. Infrared mirror; 19. First drive motor; 20. Third support frame; 21. Guide rail; 22. Sliding seat; 23. Roller; 24. Fourth support frame; 25. Installation frame; 26. Convex lens; 27. Fixing part; 28. Second support frame; 29. Second disk; 30. Third black body part; 31. Second hollow part; 32. Second drive motor; 33. Heater; 34. Radiation plate; 35. Refrigerator; 36. Vacuum pumping device. Detailed embodiments

[0026] To make the objectives, technical solutions and advantages of the present invention more clear, the following will, in conjunction with the accompanying drawings of the present invention, clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0027] The following will describe Figures 1 to 6 the low-temperature infrared radiation detection device of the present invention.

[0028] As Figures 1 to 6 shown, the low-temperature infrared radiation detection device provided by the embodiment of the present invention includes a vacuum cold box 1, an infrared detection device, a control system 7 and a signal processing system.

[0029] Specifically, the vacuum cold box 1 is used to provide a vacuum and low-temperature environment. The vacuum cold box 1 is connected with a vacuum pumping device 36, and the vacuum pumping device 36 is used to pump the vacuum cold box 1 to form a vacuum environment in the vacuum cold box 1.

[0030] The infrared detection device includes an infrared window sheet 2, an optical shutter 3, an optical lens 4, an optical chopper 5 and an infrared detector 6 arranged in sequence.

[0031] An observation port is provided on the side wall of the vacuum cold box 1, and the infrared window sheet 2 is arranged at the observation port. The infrared window sheet 2 can transmit infrared radiation signals. During use, the target object to be detected is placed outside the vacuum cold box 1, and the target object is made to correspond to the infrared window sheet 2 at the observation port.

[0032] The infrared detector 6 is arranged inside the vacuum cold box 1, and the optical shutter 3, the optical lens 4 and the optical chopper 5 are arranged in sequence between the infrared window sheet 2 and the infrared detector 6 to ensure that the infrared radiation signal of the target object located outside the observation port enters the vacuum cold box 1 and sequentially passes through the optical shutter 3, the optical lens 4, the optical chopper 5 and the infrared detector 6.

[0033] Both the optical shutter 3 and the optical chopper 5 are electrically connected to the control system 7. The optical lens 4 is used for focusing, and the optical chopper 5 is used to adjust the infrared radiation signal emitted by the target object to a predetermined frequency to improve the signal-to-noise ratio. The infrared detector 6 is used to receive the infrared radiation signal and convert it into an electrical signal.

[0034] The signal processing system includes a preamplifier 8, a lock-in amplifier 9, a signal processing unit 10, and a display unit 11 that are electrically connected in sequence. The preamplifier 8 is electrically connected to the infrared detector 6. The preamplifier 8 can amplify the electrical signal output by the infrared detector 6. The lock-in amplifier 9 is used to extract and amplify the signal corresponding to a predetermined frequency from the electrical signal amplified by the preamplifier 8 to enhance the signal strength. The signal processing unit 10 receives the amplified and enhanced signal, analyzes and processes it, and outputs the result to the display unit 11.

[0035] With such a setting, in combination with the optical chopper 5, the preamplifier 8, and the lock-in amplifier 9, the measurement accuracy of infrared detection is effectively improved.

[0036] In an embodiment of the present invention, the optical shutter 3 includes a first support frame 12, a first disk body 13, a first temperature sensor 17, an infrared reflector 18, and a first driving motor 19.

[0037] The first support frame 12 is for support, and the lower end of the first support frame 12 is supported on the bottom wall of the vacuum cold box 1. The first disk body 13 is rotatably arranged on the upper end of the first support frame 12, and the rotation axis of the first disk body 13 relative to the first support frame 12 is parallel to the distribution direction of the optical shutter 3 and the optical lens 4.

[0038] The first driving motor 19 is arranged on the first support frame 12. The first driving motor 19 is used to drive the first disk body 13 to rotate relative to the first support frame 12. The first driving motor 19 is electrically connected to the control system 7 to realize automatic control of the rotation of the first disk body 13.

[0039] Generally, the infrared window piece 2, the optical shutter 3, the optical lens 4, the optical chopper 5, and the infrared detector 6 are arranged in the horizontal direction, and the rotation axis of the first disk body 13 relative to the first support frame 12 is also arranged in the horizontal direction.

[0040] The first disk body 13 has a first black body portion 14, a second black body portion 15, and a first hollow portion 16. Referring to Figure 2 and Figure 3 , the first black body portion 14, the second black body portion 15, and the first hollow portion 16 are distributed along the circumferential direction of the first disk body 13.

[0041] By rotating the first disk body 13 relative to the first support frame 12 by different angles, each of the first black body portion 14, the second black body portion 15, and the first hollow portion 16 can correspond to the infrared window piece 2. When the first black body portion 14 or the second black body portion 15 corresponds to the infrared window piece 2, the field of view of the infrared detector 6 will be blocked, and the infrared radiation signal of the target object will be blocked from entering the infrared detector 6. When the first hollow portion 16 corresponds to the infrared window piece 2, the infrared radiation signal of the target object will enter the infrared detector 6.

[0042] The above-mentioned first black body part 14 and second black body part 15 are used to block the field of view of the infrared detector 6. As long as the first black body part 14 and the second black body part 15 can completely block the field of view of the infrared detector 6, the shapes of the first black body part 14 and the second black body part 15 are not specifically limited.

[0043] The first hollow part 16 is used for the infrared radiation signal of the target object to enter the infrared detector 6. As long as the first hollow part 16 does not block the field of view of the infrared detector 6 economically, the shape of the first hollow part 16 is not specifically limited.

[0044] The shape of the first disk body 13 can be circular, or rectangular, polygonal, etc.

[0045] Specifically, the first disk body 13 is circular, and the first black body part 14, the second black body part 15 and the first hollow part 16 are all fan-shaped, and the central angle corresponding to each fan is 120 degrees.

[0046] The first temperature sensor 17 is arranged on the first black body part 14 and the second black body part 15. The first temperature sensor 17 is used to detect the temperatures of the first black body part 14 and the second black body part 15. The first temperature sensor 17 is located on the side of the first disk body 13 away from the infrared detector 6.

[0047] The infrared mirror 18 is arranged overlapping with the second black body part 15. The infrared mirror 18 is arranged on the side of the first disk body 13 close to the infrared detector 6. The area of the infrared mirror 18 is larger than the field of view of the infrared detector 6. The emissivities of the first black body part 14 and the second black body part 15 are close to 1. The infrared mirror 18 is composed of a polished aluminum film on the surface of a glass plate, and its emissivity is n.

[0048] The working principle of the low-temperature infrared radiation detection device provided in this embodiment is as follows: The field of view of the infrared detector 6 can be blocked by the first black body part 14 and the infrared mirror 18 in sequence, and the electrical signals U1 and U2 are obtained respectively. Among them, the electrical signal U1 includes the radiation signal A1 of the first black body part 14 and the background radiation signal U b , and the electrical signal U2 includes the radiation signal A2 of the infrared mirror 18 and the background radiation signal U b . When measuring the electrical signals U1 and U2, it is necessary to ensure that the infrared window piece 2 is in a blocked state to avoid the influence of the infrared radiation outside the vacuum cold box 1. According to the signal difference algorithm, the radiation signal A1 of the first black body part 14 and the background radiation signal U bUnderstandably, the first black body part 14 and the second black body part 15 are provided for measuring background radiation. Then, the low-temperature infrared calibration curve is corrected according to the temperature detected by the first temperature sensor 17 and the radiation signal A1 of the first black body part 14 determined by calculation. Then, the first hollow part 16 is aligned with the field of view of the infrared detector 6 to obtain an electrical signal U3, and the electrical signal U3 includes the radiation signal U0 of the target object and the background radiation signal U b , and the radiation signal U0 of the target object can be determined by calculation. Furthermore, the temperature of the target object can be determined according to the corrected infrared calibration curve. The calculated radiation signal U0 of the target object does not include background radiation, and the measurement result of the temperature of the target object by the low-temperature infrared radiation detection device is not affected by background radiation, with high measurement accuracy.

[0049] According to the signal difference algorithm, the radiation signal A1 of the first black body part 14 and the background radiation signal U b are calculated and determined as follows: Since , , , so , so , . Similarly, , so .

[0050] It should be noted that the temperature in the vacuum cold box 1 is constant, and the background radiation signals included in the above electrical signals U1, U2, and U3 are regarded as the same.

[0051] With such a setting, the interference of the background radiation signal is suppressed, and the infrared calibration curve, as the basis for determining the temperature of the target object according to the radiation signal of the target object, is corrected before the start of measurement and during the measurement, making the infrared calibration curve more in line with the actual situation of the low-temperature infrared radiation detection device, thereby avoiding the accuracy of the detection result caused by the change of the low-temperature infrared radiation detection device itself.

[0052] A plurality of first temperature sensors 17 are provided, and the plurality of first temperature sensors 17 are spaced apart on the first black body part 14 and the second black body part 15. Each first temperature sensor 17 is connected to the control system 7. When rotating the first disk body 13 to align one of the first black body part 14, the infrared reflector 18, and the first hollow part 16 with the field of view of the infrared detector 6, it is necessary to avoid the first disk body 13 rotating continuously for more than one week. The cable winding between the first temperature sensor 17 and the control system 7 can be avoided by alternately rotating forward one week and then reversing one week.

[0053] In an embodiment of the present invention, the low-temperature infrared radiation detection device further includes a position adjustment device, which is arranged between the infrared detector 6 and the vacuum cold box 1. The position adjustment device is used to adjust the position of the infrared detector 6 along the distribution direction of the optical shutter 3 and the optical lens 4, so as to compensate for the focal length change caused by low temperature, ensure the clarity of the image information displayed on the display unit 11, and improve the detection accuracy.

[0054] During the process of adjusting the position of the infrared detector 6, the operation can be specifically performed according to the clarity of the image information displayed on the display unit 11.

[0055] In this embodiment, the position adjustment device includes a third support frame 20, a slide rail mechanism, and a driving mechanism.

[0056] The third support frame 20 is for support, and the lower end of the third support frame 20 is supported on the bottom wall of the vacuum cold box 1.

[0057] The slide rail mechanism includes a guide rail 21 and a sliding seat 22. The sliding seat 22 is slidably connected to the guide rail 21. The guide rail 21 is fixedly arranged at the upper end of the third support frame 20, and the axis of the guide rail 21 is parallel to the distribution direction of the optical shutter 3 and the optical lens 4. The infrared detector 6 is arranged on the sliding seat 22. By sliding the sliding seat 22 relative to the guide rail 21, the infrared detector 6 can be driven to displace, so as to adjust the distance between the infrared detector 6 and the optical chopper 5.

[0058] The driving mechanism is used to drive the sliding seat 22 to reciprocally slide relative to the guide rail 21. The driving mechanism is electrically connected to the control system 7 to realize the automatic control of the sliding of the infrared detector 6.

[0059] In this embodiment, the driving mechanism includes a roller 23 and a third driving motor.

[0060] The roller 23 is rotatably arranged on the sliding seat 22 around its own axis, and the third driving motor is used to drive the roller 23 to rotate relative to the sliding seat 22. The roller 23 can contact the slide rail mechanism and generate frictional force. When the roller 23 rotates relative to the sliding seat 22, under the action of the frictional force, the roller 23 rolls along the slide rail mechanism, thereby driving the sliding seat 22 to slide relative to the guide rail 21.

[0061] The third driving motor is electrically connected to the control system 7 to realize the automatic control of the rotation of the roller 23.

[0062] In an embodiment of the present invention, the optical lens 4 includes a fourth support frame 24, a convex lens 26, and a fixing member 27.

[0063] The fourth support frame 24 is used for support. The lower end of the fourth support frame 24 is supported on the bottom wall of the vacuum cold box 1, and an installation frame 25 is arranged at the upper end of the fourth support frame 24. The installation frame 25 is in a circular ring shape. A convex lens 26 is arranged in the installation frame 25, and the convex lens 26 is used for focusing the infrared radiation signal. A fixing member 27 is used for fixing the convex lens 26 to the installation frame 25.

[0064] In this embodiment, the support frame is made of a high-stability composite material alloy, so that the thermal expansion coefficient of the convex lens 26 is close to or the same as that of the installation frame 25, so as to reduce the influence of temperature stress on the focusing effect and ensure the stability of the low-temperature infrared radiation detection device.

[0065] A plurality of fixing members 27 are arranged, and the plurality of fixing members 27 are evenly distributed along the circumferential direction of the installation frame 25, so that the convex lens 26 is evenly stressed and the structure of the optical lens 4 is stable.

[0066] Specifically, the number of the fixing members 27 can be set to 5 to 8. Refer to Figure 4 , and 8 fixing members 27 are arranged.

[0067] In the embodiment of the present invention, the optical chopper 5 includes a second support frame 28, a second disc 29 and a second drive motor 32.

[0068] The second support frame 28 is used for support. The lower end of the second support frame 28 is supported on the bottom wall of the vacuum cold box 1. The second disc 29 is rotatably arranged on the upper end of the second support frame 28, and the rotation axis of the second disc 29 relative to the second support frame 28 is parallel to the distribution direction of the optical shutter 3 and the optical lens 4.

[0069] The second drive motor 32 is arranged on the second support frame 28. The second drive motor 32 is used for driving the second disc 29 to rotate relative to the second support frame 28. The second drive motor 32 is electrically connected to the control system 7 to realize the automatic control of the rotation of the second disc 29.

[0070] The second disc 29 has a third black body portion 30 and a second hollow portion 31. Refer to Figure 5 , two third black body portions 30 and two second hollow portions 31 are respectively arranged, and the two third black body portions 30 and the two second hollow portions 31 are spaced apart along the circumferential direction of the second disc 29.

[0071] When the second disc 29 rotates relative to the second support frame 28, as the second disc 29 rotates, the infrared radiation signal will periodically pass through the second disc 29 or be blocked by the third black body portion 30 of the second disc 29, so that the infrared radiation signal is pulse-modulated, realizing the frequency modulation of the infrared radiation signal. The modulation frequency of the infrared radiation signal depends on the rotation speed of the second disc 29.

[0072] In an embodiment of the present invention, one of a mercury cadmium telluride liquid nitrogen cooling type detector and a thermoelectric cooling type detector is selected as the infrared detector 6.

[0073] The response wavelength range of the mercury cadmium telluride liquid nitrogen cooling type detector is from 2 µm to 24 µm, and the signal collector is a 24-bit high-resolution signal collector to ensure high-precision data acquisition. The mercury cadmium telluride material has a very high quantum efficiency, which can efficiently convert the received photons into electrical signals. Moreover, when the mercury cadmium telluride liquid nitrogen cooling type detector is at a low temperature, the dark current is significantly reduced, which helps to improve the signal-to-noise ratio. The high quantum efficiency and low dark current can improve the quality of the infrared image and the detection accuracy.

[0074] In this embodiment, the cryogenic infrared radiation detection device further includes a temperature adjustment device, which is used to adjust the temperatures of the infrared detector 6 and the vacuum cold box 1 within a preset range, so that the temperatures of the infrared detector 6 and the vacuum cold box 1 are kept stable, ensuring the consistency and reliability of the detection accuracy during long-term detection.

[0075] The temperature adjustment device includes a heater 33, a radiation plate 34, a refrigerator 35 and a second temperature sensor. The heater 33 and the radiation plate 34 are arranged inside the vacuum cold box 1, and the radiation plate 34 is fixedly arranged on the top of the vacuum cold box 1 for radiating heat to other positions of the vacuum cold box 1, so as to form a low-temperature environment inside the vacuum cold box 1.

[0076] The infrared detector 6 has a heat exchange shell, and the radiation plate 34 has a heat exchange cavity. Both the heat exchange shell and the heat exchange cavity can allow liquid nitrogen to flow through. The refrigerator 35, the heat exchange shell, the heater 33 and the radiation plate 34 are connected to form a closed loop. The refrigerator 35 is used for refrigeration and outputting liquid nitrogen. The liquid nitrogen flows through the heat exchange shell of the infrared detector 6, the heater 33 and the radiation plate 34 and then returns to the refrigerator 35. When the liquid nitrogen flows through the heat exchange shell of the infrared detector 6, the temperature of the infrared detector 6 is reduced. When it flows through the radiation plate 34, the temperature of the radiation plate 34 is reduced.

[0077] The second temperature sensor is arranged on the radiation plate 34 for detecting the temperature of the radiation plate 34. The heater 33, the second temperature sensor and the refrigerator 35 are all electrically connected to the control system 7. According to the detection result of the second temperature sensor, the operation of the heater 33 and the refrigerator 35 is controlled to precisely control the temperatures of the infrared detector 6 and the low-temperature cold box.

[0078] In addition, the temperatures detected by the second temperature sensor and the first temperature sensor 17 respectively represent the temperatures of different positions of the vacuum cold box 1. The control system 7 can also control the operation of the heater 33 and the refrigerator 35 according to the detection results of the first temperature sensor 17 and the second temperature sensor, so as to precisely control the temperatures of the infrared detector 6 and the low-temperature cold box and ensure the stability of the temperature inside the vacuum cold box 1.

[0079] During the specific use process, first, the vacuum cold box 1 is evacuated by the vacuum pumping device 36, and then the vacuum cold box 1 is cooled by liquid nitrogen and the radiation plate 34. When the refrigerator 35, the heat exchange shell, the heater 33 and the radiation plate 34 are connected to form a closed loop, they are connected by metal hoses between adjacent ones.

[0080] The material of the above-mentioned radiation plate 34 is copper.

[0081] In the embodiment of the present invention, a polished aluminum layer is provided outside the radiation plate 34, outside the infrared mirror 18, outside the heater 33, and outside the first driving motor 19, the second driving motor 32 and the third driving motor. The setting of the polished aluminum layer can increase the infrared reflectivity, reduce the emissivity, and prevent the stray radiation of the corresponding parts from affecting the detection accuracy of the infrared detector 6.

[0082] It should be noted that the above background radiation signals include the environmental radiation of the vacuum cold box 1, the radiation of the second driving motor 32 of the optical chopper 5, the radiation of the first driving motor 19 of the optical shutter 3, the radiation of the optical lens 4, the radiation of the infrared detector 6 and the temperature regulating device. By stabilizing the temperature of the infrared detector 6 and the temperature inside the vacuum cold box 1 through the temperature regulating device, the temperature stability of the optical chopper 5, the optical shutter 3, the optical lens 4 and the temperature regulating device can be ensured, thereby ensuring the stability of the background radiation signal.

[0083] In summary, the low-temperature infrared radiation detection device provided by the embodiment of the present invention combines the use of the optical chopper 5, the preamplifier 8, the lock-in amplifier 9, the signal differential algorithm and the mercury cadmium telluride liquid nitrogen cooling type detector, effectively improving the detection accuracy and stability in a low-temperature environment, and achieving high-precision and low-noise infrared radiation detection of target objects below -120°C.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-temperature infrared radiation detection device, characterized in that Comprising: A vacuum cold box (1), on the side wall of which an observation port is provided; An infrared detection device, including an infrared window plate (2), an optical shutter (3), an optical lens (4), an optical chopper (5) and an infrared detector (6) arranged in sequence. The infrared window plate (2) is arranged at the observation port, the infrared detector (6) is arranged inside the vacuum cold box (1), the optical shutter (3), the optical lens (4) and the optical chopper (5) are arranged in sequence between the infrared window plate (2) and the infrared detector (6). The optical chopper (5) is adapted to adjust the infrared radiation signal emitted by the target object to a predetermined frequency, and the infrared detector (6) is adapted to receive the infrared radiation signal and convert it into an electrical signal; A control system (7), both the optical shutter (3) and the optical chopper (5) are electrically connected to the control system (7); A signal processing system, including a preamplifier (8), a lock-in amplifier (9), a signal processing unit (10) and a display unit (11) electrically connected in sequence. The preamplifier (8) is electrically connected to the infrared detector (6). The preamplifier (8) is adapted to amplify the electrical signal output by the infrared detector (6). The lock-in amplifier (9) is adapted to extract and amplify the signal corresponding to the predetermined frequency from the electrical signal amplified by the preamplifier (8). The signal processing unit is adapted to receive the signal output by the lock-in amplifier (9), analyze and process it, and output the result to the display unit.

2. The low-temperature infrared radiation detection device according to claim 1, wherein The optical shutter (3) includes: A first support frame (12), the lower end of which is supported on the bottom wall of the vacuum cold box (1); A first disk body (13), rotatably arranged on the upper end of the first support frame (12). The first disk body (13) has a first black body part (14), a second black body part (15) and a first hollow part (16) distributed along its circumferential direction; A first temperature sensor (17), arranged on the first black body part (14) and the second black body part (15). The first temperature sensor (17) is arranged on the side of the first disk body (13) away from the infrared detector (6); An infrared reflecting mirror (18), arranged overlapping with the second black body part (15). The infrared reflecting mirror (18) is arranged on the side of the first disk body (13) close to the infrared detector (6); A first driving motor (19), arranged on the first support frame (12). The first driving motor (19) is adapted to drive the first disk body (13) to rotate relative to the first support frame (12). The first driving motor (19) is electrically connected to the control system (7).

3. The cryogenic infrared radiation detection device according to claim 2, wherein, The first disk body (13) is circular, and the first black body part (14), the second black body part (15) and the first hollow part (16) are all fan-shaped, and the central angles corresponding to the sectors are all 120 degrees.

4. The cryogenic infrared radiation detection device according to claim 1, characterized in that, Also including: A position adjusting device is arranged between the infrared detector (6) and the vacuum cold box (1), and the position adjusting device is adapted to adjust the position of the infrared detector (6) along the distribution direction of the optical shutter (3) and the optical lens (4).

5. The cryogenic infrared radiation detection device according to claim 4, characterized in that, The position adjusting device includes: A third support frame (20), the lower end of the third support frame (20) is supported on the bottom wall of the vacuum cold box (1); A slide rail mechanism, including a guide rail (21) and a sliding seat (22) slidably connected to the guide rail (21), the axis of the guide rail (21) is parallel to the distribution direction of the optical shutter (3) and the optical lens (4), and the infrared detector (6) is arranged on the sliding seat (22); A driving mechanism, adapted to drive the sliding seat (22) to reciprocally slide relative to the guide rail (21), and the driving mechanism is electrically connected to the control system (7).

6. The cryogenic infrared radiation detection device according to claim 1, characterized in that, The optical lens (4) includes: A fourth support frame (24), the lower end of the fourth support frame (24) is supported on the bottom wall of the vacuum cold box (1), and the upper end of the fourth support frame (24) is provided with a mounting frame (25), and the mounting frame (25) is circular; A convex lens (26) is arranged in the mounting frame (25), the convex lens (26) is adapted to focus the infrared radiation signal, and the thermal expansion coefficient of the convex lens (26) is the same as that of the mounting frame (25); Fixing members (27), adapted to fix the convex lens (26) to the mounting frame (25), there are a plurality of the fixing members (27), and the plurality of fixing members (27) are evenly distributed along the circumferential direction of the mounting frame (25).

7. The cryogenic infrared radiation detection device according to claim 1, characterized in that The optical chopper (5) includes: A second support frame (28), the lower end of the second support frame (28) is supported on the bottom wall of the vacuum cold box (1); A second disc (29) is rotatably arranged on the upper end of the second support frame (28), and the second disc (29) has a third black body part (30) and a second hollow part (31) spaced apart along its circumferential direction; A second driving motor (32) is arranged on the second support frame (28), the second driving motor (32) is adapted to drive the second disc (29) to rotate relative to the second support frame (28), and the second driving motor (32) is electrically connected to the control system (7).

8. The cryogenic infrared radiation detection device according to any one of claims 1-7, characterized in that The infrared detector (6) is one of a mercury cadmium telluride cryogenic refrigeration type detector and a thermoelectric refrigeration type detector.

9. The low-temperature infrared radiation detection device according to claim 8, wherein, It further includes: A temperature regulating device is adapted to regulate the temperatures inside the infrared detector (6) and the vacuum cold box (1) within a preset range. The temperature regulating device includes a heater (33), a radiation plate (34), a refrigerator (35), and a second temperature sensor. The heater (33) and the radiation plate (34) are disposed inside the vacuum cold box (1). The second temperature sensor is disposed on the radiation plate (34). The infrared detector (6) has a heat exchange shell through which liquid nitrogen can flow. The radiation plate (34) has a heat exchange cavity inside for liquid nitrogen to flow through. The refrigerator (35), the heat exchange shell, the heater (33), and the radiation plate (34) are connected to form a closed loop. The heater (33), the second temperature sensor, and the refrigerator (35) are all electrically connected to the control system (7).

10. The cryogenic infrared radiation detection device according to claim 9, characterized in that, A polished aluminum layer is provided on the outside of the radiation plate (34) and the outside of the heater (33).

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