A miniaturized, high-precision infrared array thermal imager

Abstract

This invention provides a miniaturized, high-precision infrared thermal imager, solving the problems of existing infrared thermal imagers being bulky, requiring the blackbody furnace and the target to be in the same field of view for calibration, resulting in cumbersome operation and low temperature measurement accuracy in situations where a blackbody furnace cannot be placed. The imager includes an infrared thermal imaging system and a calibration imaging system. The infrared thermal imaging system includes a housing and, coaxially arranged, an uncooled thermal imager module, a long-wave infrared lens, a first shutter, a second shutter, and a sealed window. The sealed window is located on the housing, while the uncooled thermal imager module, long-wave infrared lens, first shutter, and second shutter are all located inside the housing. The calibration imaging system includes a reference heat source, a calibration infrared lens, and a folding assembly, all housed within the housing. The emitted beam from the reference heat source is collimated by the calibration infrared lens, its transmission direction is changed by the folding assembly, and it is transmitted through the first shutter before entering the long-wave infrared lens and then the uncooled thermal imager module.

Description

Technical Field

[0001] This invention relates to infrared imaging temperature measurement technology, specifically to a miniaturized, high-precision infrared array thermal imager. Background Technology

[0002] Any object with a temperature above thermodynamic zero will radiate infrared radiation. Infrared radiation is essentially thermal radiation; the higher the temperature of an object, the more energy it radiates.

[0003] Infrared imaging temperature measurement devices utilize an infrared optical system to concentrate the energy radiated by an object onto a detector, causing a change in a certain parameter within the detector. By detecting this parameter change, the radiated energy can be detected, and thus the temperature of the object's surface can be measured.

[0004] Infrared imaging temperature measurement devices have two main uses: industrial temperature measurement, which monitors the status of industrial equipment and identifies abnormal heat points to pinpoint potential hazards; and human body temperature measurement, which can be used for body temperature screening or disease detection in public places. The former requires a wider temperature range and lower accuracy, typically ±2℃; the latter requires higher accuracy, typically ±0.5℃, with high-precision requirements reaching ±0.3℃.

[0005] Higher temperature measurement accuracy provides more accurate and reliable temperature information for the target. Currently, high-precision thermal imagers primarily use a combination of a blackbody furnace and an infrared thermal imaging system, achieving an accuracy of ±0.3℃. The method involves mounting the blackbody furnace on a tripod, powering it on, and placing it and the target within the same field of view of the infrared thermal imaging system. The blackbody furnace serves as a reference heat source, and the infrared thermal imaging system simultaneously measures the temperatures of both the furnace and the target. The difference between the furnace temperature and the measured temperature is used to correct the imager's accuracy drift in real time. This method requires the coordinated use of a blackbody furnace and a tripod, and can only measure the temperature of targets in the same direction as the furnace. It also requires aligning the blackbody furnace and target within the same field of view, making it relatively cumbersome. In situations where a blackbody furnace cannot be placed at the target location, the measurement accuracy is low and fails to meet the requirements for high-precision temperature measurement. Furthermore, existing infrared thermal imagers involve numerous components, resulting in a large overall size and making miniaturization difficult. Summary of the Invention

[0006] To address the technical problems of existing infrared thermal imagers being bulky, difficult to miniaturize, requiring the blackbody furnace and the target to be in the same field of view for calibration, resulting in cumbersome operation, and low temperature measurement accuracy, especially in situations where a blackbody furnace cannot be placed, this invention provides a miniaturized, high-precision infrared external array thermal imager.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0008] A miniaturized, high-precision infrared thermal imager includes an infrared thermal imaging system. The infrared thermal imaging system includes a housing and an uncooled thermal imager mechanism, a long-wave infrared lens, a first shutter, a second shutter, and a sealed window arranged coaxially in sequence. The sealed window is located on the housing, and the uncooled thermal imager mechanism, the long-wave infrared lens, the first shutter, and the second shutter are all located inside the housing. Its special feature is that it also includes a calibration imaging system disposed inside the housing.

[0009] The calibration imaging system includes a reference heat source, a calibration infrared lens, and a folding assembly;

[0010] The emitted beam from the reference heat source passes sequentially through the calibration infrared lens for collimation, the folding component to change the transmission direction, and the first shutter for transmission before entering the long-wave infrared lens and then the uncooled thermal imager core.

[0011] Furthermore, the folding assembly includes a first reflector and a second reflector, the reflective surfaces of the first reflector and the second reflector are arranged facing each other and the included angle between the mirror surfaces is 90°;

[0012] The second reflector is located in the output light path of the calibrating infrared lens;

[0013] The first reflector is located on the refracted light path of the second reflector and between the first shutter and the second shutter. The first reflector has an angle of 45° with the optical axis of the long-wave infrared lens and is located on one side of the optical axis of the long-wave infrared lens. The lateral dimension of the reflective surface of the first reflector projected onto the long-wave infrared lens is less than 1 / 2 of the diameter of the long-wave infrared lens.

[0014] Furthermore, the reference heat source is a miniaturized surface heat source with temperature control effect.

[0015] Furthermore, both the first and second reflectors are coated with anti-reflective coatings.

[0016] Furthermore, the first reflector is coated with a semi-transparent and semi-reflective film, and the second reflector is coated with an anti-reflective film.

[0017] Furthermore, the effective blocking size of the first shutter is larger than the field of view of the long-wave infrared lens at the first shutter position;

[0018] The effective blocking size of the second shutter is larger than the field of view of the long-wave infrared lens at the second shutter position.

[0019] Furthermore, the sealing window is made of germanium, with a hard carbon film coated on the outer surface and an anti-reflection film coated on the inner surface.

[0020] Furthermore, the folding component is an orthographic prism or a beam-splitting orthographic prism;

[0021] The rhomboid prism or beam-splitting rhomboid prism is located on the output light path of the calibrating infrared lens and between the first shutter and the second shutter. The output beam of the rhomboid prism or beam-splitting rhomboid prism is located on one side of the optical axis of the long-wave infrared lens.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] 1. Based on existing infrared thermal imaging technology, the thermal imager of this invention directly integrates the reference heat source into the housing, eliminating the need to place a blackbody furnace near the target. Furthermore, during temperature measurement, it is not necessary to adjust the reference heat source (existing blackbody furnace) and the target to be in the same field of view. Temperature measurement can be performed as long as the thermal imager observes the target, making the operation extremely convenient.

[0024] 2. The thermal imager of this invention replaces the blackbody furnace with a miniaturized surface heat source, and the overall volume of the calibration imaging system is much smaller than that of the existing blackbody furnace. Therefore, the thermal imager of this invention has the characteristics of small size and high integration while meeting the requirements of high-precision temperature measurement.

[0025] 3. The thermal imager of the present invention can measure targets in situations where a blackbody furnace cannot be placed near the target, such as steel furnaces in steel plants, high-voltage power lines, or chemical equipment containing hazardous gases. Since the thermal imager of the present invention does not require a reference heat source to be placed next to the target, it can measure targets in these special situations.

[0026] 4. In order to further reduce the size of the thermal imager, the folding assembly includes two mirrors that fold the emitted beam of the reference light source by 180°. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the miniaturized high-precision infrared thermal imager of the present invention.

[0028] The reference numerals in the attached figures are as follows:

[0029] 1-Uncooled thermal imager mechanism, 2-Long-wave infrared lens, 3-Shutter assembly, 31-First shutter, 32-Second shutter, 4-Folding assembly, 41-First reflector, 42-Second reflector, 5-Calibration infrared lens, 6-Reference heat source, 7-Housing, 71-Sealed window. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0031] like Figure 1As shown, a miniaturized, high-precision infrared array thermal imager consists of an infrared thermal imaging system and a calibration imaging system.

[0032] The infrared thermal imaging system includes a housing 7 and an uncooled thermal imager mechanism 1, a long-wave infrared lens 2, a shutter assembly 3, and a sealing window 71 arranged coaxially. The shutter assembly 3 includes a first shutter 31 and a second shutter 32 arranged in sequence. The uncooled thermal imager mechanism 1, the long-wave infrared lens 2, the first shutter 31, and the second shutter 32 are all located inside the housing 7. The sealing window 71 is located on the housing 7 and can be composed of an infrared germanium window. It is responsible for allowing light to pass through the infrared imaging optical system and sealing the light-transmitting area of ​​the thermal imager. The surface of the sealing window 71 located outside the housing is coated with a hard carbon film, and the surface of the sealing window 71 located inside the housing is coated with an anti-reflection film.

[0033] The calibration imaging system and the infrared thermal imaging system share the same long-wave infrared lens 2 and uncooled thermal imager core 1. The calibration imaging system consists of a reference heat source 6, a calibration infrared lens 5, a folding assembly 4, a first shutter 31, a long-wave infrared lens 2, and an uncooled thermal imager core 1.

[0034] Reference heat source 6 is a miniaturized surface heat source with temperature control effect, which makes the overall volume of the calibration imaging system much smaller than that of the existing blackbody furnace. This allows the thermal imager to meet the requirements of high-precision temperature measurement while also being small in size and highly integrated.

[0035] The calibration infrared lens 5 is responsible for collecting the infrared beam emitted by the reference heat source 6 and projecting it out in parallel.

[0036] The folding assembly 4 is used to change the direction of the beam emitted from the calibration infrared lens 5. The folding assembly 4 consists of a first reflector 41, a second reflector 42, and a corresponding support structure. Its purpose is to allow the infrared beam emitted from the reference heat source 6 to enter the long-wave infrared lens 2. The second reflector 42 is located on the outgoing light path of the calibration infrared lens 5, forming a 45° angle with the outgoing light path. The first reflector 41 is located on the outgoing light path of the second reflector 42, forming a 90° angle with the second reflector 42. Reflective films are coated on the inner surfaces of both the first reflector 41 and the second reflector 42. In other embodiments, the first reflector 41 may also be coated with a semi-transparent and semi-reflective film. The first reflector 41 forms a 45° angle with the optical axis of the long-wave infrared lens 2 and is located on one side of the optical axis of the long-wave infrared lens 2. The lateral dimension of the reflective surface of the first reflector 41 projected onto the long-wave infrared lens 2 is less than 1 / 2 of the light-transmitting diameter of the long-wave infrared lens 2.

[0037] The emitted beam from the reference heat source 6 is collimated by the calibration infrared lens 5, reflected by the second reflector 42, reflected by the first reflector 41, transmitted through the first shutter 31, and transmitted through the long-wave infrared lens 2 before being imaged onto the uncooled thermal imager module 1. The first shutter 31 is positioned between the first reflector 41 and the long-wave infrared lens 2 to perform non-uniform correction on the infrared thermal imager. In other embodiments, the folding assembly 4 can be composed of two reflectors with their surfaces perpendicular to each other, or it can be a single reflector, an orthographic prism, or a beam-splitting orthographic prism.

[0038] In this embodiment, the effective blocking size of the first shutter 31 and the second shutter 32 in the thermal imager is larger than the field of view of the long-wave infrared lens 2 at the shutter position. The first shutter 31 is located between the long-wave infrared lens 2 and the first reflector 41, and its effective blocking size is larger than the light-transmitting size of the infrared thermal imaging system at the shutter mounting position. The second shutter 32 is located between the first reflector 41 and the sealing window 71, and its effective blocking size is larger than the light-transmitting size of the infrared thermal imaging system at the shutter mounting position.

[0039] The usage process of the thermal imager in this embodiment is as follows:

[0040] 1) Set up the infrared thermal imager next to the target to be measured, so that the field of view of the long-wave infrared lens of the infrared thermal imager is facing the target to be measured.

[0041] 2) Power on the infrared thermal imager and turn it on. Confirm that the target to be measured is within the working image of the infrared thermal imager, and set the temperature value T1 of the reference heat source.

[0042] 3) The long-wave infrared lens receives the energy radiated by the target and focuses it onto the uncooled thermal imager core. Based on the change of a certain parameter in the detector of the uncooled thermal imager core, the temperature value T2 of the target is obtained.

[0043] Meanwhile, the energy of the reference heat source passes through the calibration infrared lens, the second reflector, the first reflector, and the first shutter in sequence before being incident on the long-wave infrared lens and focused on the uncooled thermal imager core. Based on the change of a certain parameter in the detector of the uncooled thermal imager core, the measured temperature value T3 of the reference heat source is obtained.

[0044] 4) Read the temperature value T2 of the target to be measured and the measured temperature value T3 of the reference heat source, and calculate the difference ΔT between the measured temperature value T3 of the reference heat source and the set value T1 of the reference heat source based on the temperature value T1 of the reference heat source. Correct the accuracy drift of the thermal imager in real time based on ΔT.

[0045] For example: the reference heat source temperature T1 is 35℃, the measured temperature of the reference heat source T3 is 35.2℃, and the measured temperature of the target is T2 45℃; then ΔT=(T3-T1)=35.2℃-35℃=0.2℃, the actual target temperature T=T2-ΔT=45℃-0.2℃=44.8℃, and the target temperature is read as 44.8℃ through the operating software, and the measurement ends.

[0046] The above description is merely of preferred embodiments of the present invention and does not limit the technical solution of the present invention to these embodiments. Any well-known modifications made by those skilled in the art based on the main technical concept of the present invention shall fall within the scope of the technology to be protected by the present invention.

Claims

1. A miniaturized high-precision infrared thermal imager, comprising an infrared thermal imaging system, wherein the infrared thermal imaging system comprises a housing (7) and an uncooled thermal imager mechanism (1), a long-wave infrared lens (2), a first shutter (31), a second shutter (32), and a sealed window (71) arranged coaxially in sequence, the sealed window (71) being located on the housing (7), and the uncooled thermal imager mechanism (1), the long-wave infrared lens (2), the first shutter (31), and the second shutter (32) all being located inside the housing (7), characterized in that: It also includes a calibration imaging system housed within the housing (7); The calibration imaging system includes a reference heat source (6), a calibration infrared lens (5), and a folding assembly (4); The beam emitted from the reference heat source (6) passes through the calibration infrared lens (5) for collimation, the folding assembly (4) for direction change, and the first shutter (31) for transmission before entering the long-wave infrared lens (2) and then into the uncooled thermal imager core (1). When in use, the temperature value T1 of the reference heat source (6) is set, the long-wave infrared lens (2) receives the energy radiated by the target and the energy of the reference heat source (6), and then, according to the parameter changes of the detector in the uncooled thermal imager core (1), the temperature value T2 of the target and the measured temperature value T3 of the reference heat source (6) are obtained at the same time. Based on the temperature value T1 of the reference heat source (6) and the measured temperature value T3, the measurement accuracy drift is corrected in real time.

2. The miniaturized high-precision infrared thermal imager according to claim 1, characterized in that: The folding assembly (4) includes a first reflector (41) and a second reflector (42), the reflective surfaces of the first reflector (41) and the second reflector (42) are arranged facing each other and the included angle between the mirror surfaces is 90°; The second reflector (42) is located in the output light path of the calibration infrared lens (5); The first reflector (41) is located on the refracted light path of the second reflector (42) and between the first shutter (31) and the second shutter (32). The first reflector (41) has an angle of 45° with the optical axis of the long-wave infrared lens (2) and is located on one side of the optical axis of the long-wave infrared lens (2). The lateral dimension of the reflective surface of the first reflector (41) projected onto the long-wave infrared lens (2) is less than 1 / 2 of the diameter of the long-wave infrared lens (2).

3. The miniaturized high-precision infrared array thermal imager according to claim 2, characterized in that: The reference heat source (6) is a miniaturized surface heat source with temperature control effect.

4. The miniaturized high-precision infrared thermal imager according to claim 3, characterized in that: Both the first reflector (41) and the second reflector (42) are coated with anti-reflection film.

5. The miniaturized high-precision infrared thermal imager according to claim 3, characterized in that: The first reflector (41) is coated with a semi-transparent and semi-reflective film, and the second reflector (42) is coated with an anti-reflective film.

6. The miniaturized high-precision infrared array thermal imager according to any one of claims 1 to 5, characterized in that: The effective blocking size of the first shutter (31) is larger than the size of the field of view of the long-wave infrared lens (2) at the position of the first shutter (31); The effective blocking size of the second shutter (32) is larger than the size of the field of view of the long-wave infrared lens (2) at the position of the second shutter (32).

7. The miniaturized high-precision infrared thermal imager according to claim 6, characterized in that: The sealing window (71) is made of germanium, with a hard carbon film on the outer surface and an anti-reflective film on the inner surface.

8. The miniaturized high-precision infrared array thermal imager according to claim 1, characterized in that: The folding component (4) is an orthographic prism or a beam-splitting orthographic prism; The rhomboid prism or beam-splitting rhomboid prism is located on the output light path of the calibration infrared lens (5) and between the first shutter (31) and the second shutter (32). The output beam of the rhomboid prism or beam-splitting rhomboid prism is located on one side of the optical axis of the long-wave infrared lens (2).

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