Strong-electromagnetic-resistance thermal infrared imager structure

Abstract

The utility model discloses a strong-electromagnetic-resistant thermal infrared imager structure which comprises a main frame, an optical cabin and a turning frame. According to the strong-electromagnetic-resistant thermal infrared imager structure, a sealed light cabin structural form is adopted, so that an internal light path channel plays a role of cutting off a waveguide tube. In addition, a grating divider structure is additionally arranged between a rear group lens cone and a cut-off waveguide tube at the rear end of the light path, electromagnetic pulses entering the light cabin are divided and attenuated, light is turned by a first refractor group, a turning frame, a second refractor group, a rear lens group and a grating light filter, and meanwhile, an internal channel plays a role of the cut-off waveguide tube. A power supply line entering the interior is filtered through an internal power filter, and it is guaranteed that interference current is not brought into an internal circuit. Therefore, the strong electromagnetic pulse is effectively prevented, the internal circuit of the thermal infrared imager is protected, and the normal work of the thermal infrared imager is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of infrared thermal imagers, in particular to a strong electromagnetic resistant infrared thermal imager structure. Background Art

[0002] Infrared search and tracking systems have developed rapidly in recent years. Due to their good concealment, wide detector range, and high positioning accuracy, infrared search and tracking systems are currently widely used in various industries. In order to meet the needs of various environments and working conditions, different structural forms need to be designed to meet the functional and performance requirements of the product.

[0003] With the continuous development of electronic technology, various infrared thermal imager products need to meet some relatively harsh environmental conditions. Strong electromagnetic pulses can enter the interior of the product through antennas, cable connections, metal pipes, etc., causing the product to induce current, interfere with the product's operation or damage its function.

[0004] There is relatively little research on strong electromagnetic pulse protection in China. Currently, the main protection methods are electromagnetic shielding, filtering and grounding.

[0005] EMP (high intensity electromagnetic pulse) is extremely destructive to products and usually causes irreversible damage. Therefore, a strong electromagnetic resistant infrared thermal imager structure is proposed to facilitate prevention of strong electromagnetic pulses, protect the internal circuit of the infrared thermal imager, and ensure that the infrared thermal imager can work normally. Utility Model Content

[0006] The purpose of the utility model is to provide a strong electromagnetic resistant infrared thermal imager structure to solve the problem that during the use of the infrared thermal imager proposed in the above background technology, EMP (high intensity electromagnetic pulse) is extremely destructive to the product and usually causes irreversible damage.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A structure of an infrared thermal imager resistant to strong electromagnetic waves comprises a main frame, wherein an optical machine cabin is arranged on one side of the bottom of the main frame, a turning frame is connected through the top of the tail end of the optical machine cabin, a rear lens group is fixedly connected to the tail end of the turning frame, a cut-off waveguide is connected to the tail end of the rear lens group, an electromagnetic shielding tape is wound around the outer side of the connection between the rear lens group and the cut-off waveguide, a rear lens group is installed on the inner side of the tail end of the turning frame, a first refraction lens group and a second refraction lens group are installed at the inlet end and the turning point of the turning frame respectively, the second refraction lens group corresponds to the rear lens group, a variable magnification lens group, a compensation lens group and a focusing lens group are sequentially installed at the optical machine cabin corresponding to the first refraction lens group, a front lens group is installed at the port of the optical machine cabin corresponding to the variable magnification lens group, a grid filter is placed on the end face of the rear lens group, and the grid filter is a cross divider or a honeycomb mesh divider.

[0009] As a further solution of the utility model: the infrared detector is externally connected to an internal circuit module, and the corresponding connection ports of the internal circuit module are respectively connected to a power filter and an output optical fiber through internal connecting lines, the output optical fiber passes through and is fixedly connected to the upper part of the other side of the main frame, and the power filter is fixedly installed on the lower side wall of the other side of the main frame.

[0010] As a further solution of the utility model: an external threaded joint is provided on the end face of the rear mirror group, an internal thread is provided on the inner side of the cutoff waveguide, the cutoff waveguide is threadedly connected to the rear mirror group, and the grid filter is clamped and fixed between the cutoff waveguide and the rear mirror group.

[0011] As a further solution of the utility model: an adjustment component is provided between the variable power lens group and the compensation lens group, and the adjustment component includes a first linear guide rail, a second linear guide rail, a cam shaft and a sliding guide pin.

[0012] As a further solution of the utility model: the zoom lens group is slidably installed on the second linear guide rail, and the compensating lens group is slidably installed on the first linear guide rail. Both the zoom lens group and the compensating lens group are equipped with sliding guide pins, which are connected to the camshaft, and the camshaft is driven by a motor.

[0013] As a further solution of the utility model: an inspection port is also provided on the main frame, and a cover plate matching the inspection port is provided inside the inspection port, a circular shielding sealing strip is provided between the contact surface of the cover plate and the inspection port, the cover plate is fixed to the main frame by screws, a circular hole for the screws to pass through is provided on the cover plate, the inspection port is arranged in a stepped manner, and a threaded hole for screw threaded connection is provided on the step surface.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] 1. The utility model adopts a sealed optical cabin structure, so that the internal optical path channel plays the role of a cutoff waveguide. The cutoff waveguide with an inner diameter of 2.4 cm is designed to ensure that the electromagnetic pulse signal entering the optical path is strictly shielded and attenuated without affecting the optical and detector target imaging. In addition, a grid divider structure is added between the rear group lens barrel and the cutoff waveguide at the rear end of the optical path to divide and attenuate the electromagnetic pulse entering the optical cabin. The first refractor group, the folding frame, the second refractor group, the rear lens group, and the grid filter realize the folding of light. At the same time, the internal channel plays the role of a cutoff waveguide to shield and attenuate the strong electromagnetic pulse entering the sealed optical path. After the external power supply line is connected to the internal connecting line through the power filter, power is provided to the internal circuit module. After the internal circuit module processes the photoelectric conversion signal, the image information is output to the host system through the output optical fiber. The power supply line entering the internal power supply is filtered through the internal power filter to ensure that no interference current is brought into the internal circuit. This can effectively prevent strong electromagnetic pulses, protect the internal circuit of the infrared thermal imager, and ensure that the infrared thermal imager can work normally.

[0016] 2. In the present invention, the grid filter 14 is threadedly installed and pressed inside through the cutoff waveguide 21 and the rear lens group 19, so that the grid filter 14 can be quickly replaced without changing the debugging optical axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The figure is a schematic diagram of the structure of an infrared thermal imager that is resistant to strong electromagnetic fields.

[0018] Figure 2 This is a structural diagram of the grid divider installation in a strong electromagnetic resistant infrared thermal imager structure.

[0019] Figure 3 The structure diagram of a variable field of view in a strong electromagnetic resistant infrared thermal imager structure.

[0020] Figure 4 This is a diagram of the main frame open-frame shielding and sealing structure in a strong electromagnetic resistant infrared thermal imager structure.

[0021] Figure 5 This is a schematic diagram of a power filter circuit in a strong electromagnetic resistant infrared thermal imager structure.

[0022] In the figure: 1, front lens group; 2, optical cabin; 3, zoom lens group; 4, compensation lens group; 5, focusing lens group; 6, first refractor group; 7, folding frame; 8, power supply filter; 9, main frame; 10, output optical fiber; 11, internal connecting line; 12, second refractor group; 13, rear lens group; 14, grid filter; 15, electromagnetic shielding tape; 16, infrared detector; 17, internal circuit module; 18, imaging beam; 19, rear lens group; 21, cutoff waveguide; 22, first linear guide; 23, second linear guide; 24, camshaft; 25, sliding guide pin; 26, circular shielding sealing strip; 27, cover plate; 28, screw. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] See also Figures 1 to 5 In the embodiment of the utility model, a strong electromagnetic resistant infrared thermal imager structure includes a main frame 9, an optical cabin 2 is arranged on one side of the bottom of the main frame 9, a turning frame 7 is connected through the top of the tail end of the optical cabin 2, a rear mirror group 19 is fixedly connected to the tail end of the turning frame 7, a cutoff waveguide 21 is connected to the tail end of the rear mirror group 19, the cutoff waveguide 21 is connected to the optical window of the infrared detector 16, an electromagnetic shielding tape 15 is wrapped around the outer side of the connection between the rear mirror group 19 and the cutoff waveguide 21, and the turning frame 7 is fixedly connected to the tail end of the rear mirror group 19. A rear lens group 13 is installed on the inner side of the tail end, a first refractive lens group 6 and a second refractive lens group 12 are installed at the entrance and the turning point of the turning frame 7 respectively, the second refractive lens group 12 corresponds to the rear lens group 13, a zoom lens group 3, a compensation lens group 4 and a focusing lens group 5 are installed in sequence at the optical cabin 2 corresponding to the first refractive lens group 6, a front lens group 1 is installed at the port of the optical cabin 2 corresponding to the zoom lens group 3, a grid filter 14 is placed on the end face of the rear lens group 19, and the grid filter 14 is a cross divider or a honeycomb mesh divider.

[0025] The sealed optical cabin 2 structure is adopted, so that the internal optical path channel plays the role of a cutoff waveguide. The cutoff waveguide 21 with an inner diameter of 2.4 cm is designed to ensure that the electromagnetic pulse signal entering the optical path is strictly shielded and attenuated without affecting the optical and detector target imaging. In addition, a grid divider 14 structure is added between the rear group lens barrel 19 and the cutoff waveguide 21 at the rear end of the optical path to divide and attenuate the electromagnetic pulse entering the optical cabin 2. The first refractor group 6, the folding frame 7, the second refractor group 12, the rear lens group 13, and the grid filter 14 realize the folding of light. At the same time, the internal channel plays the role of a cutoff waveguide to shield and attenuate the strong electromagnetic pulse entering the sealed optical path. After the external power supply line is connected to the internal connecting line 11 through the power filter 8, power is provided to the internal circuit module 17. After the internal circuit module 17 processes the photoelectric conversion signal, the image information is output to the host system through the output optical fiber 10. The power supply line entering the internal power supply line passes through the internal power filter for filtering processing to ensure that no interference current is brought into the internal circuit. This can effectively prevent strong electromagnetic pulses, protect the internal circuit of the infrared thermal imager, and ensure that the infrared thermal imager can work normally.

[0026] The infrared detector 16 is externally connected to an internal circuit module 17, and the corresponding connection ports of the internal circuit module 17 are respectively connected to a power filter 8 and an output optical fiber 10 through internal connecting lines 11. The output optical fiber 10 passes through and is fixedly connected to the upper part of the other side of the main frame 9, and the power filter 8 is fixedly installed on the lower side wall of the other side of the main frame 9.

[0027] An external threaded joint is provided on the end surface of the rear lens group 19, and an internal thread is provided on the inner side of the cutoff waveguide 21. The cutoff waveguide 21 is threadedly connected to the rear lens group 19, and the grid filter 14 is clamped and fixed between the cutoff waveguide 21 and the rear lens group 19. Tests have found that the grid filter 14 has an impact on the imaging effect at different positions, and it cannot be too close to the window of the infrared detector 16, otherwise the grid filter 14 may be imaged on the image. Therefore, the grid filter 14 must be designed to be as close to the side of the rear lens group as possible.

[0028] The grid filter 14 is threadedly installed and pressed inside through the cutoff waveguide 21 and the rear lens group 19, so that the grid filter 14 can be quickly disassembled and replaced without changing the debugging optical axis.

[0029] An adjustment component is provided between the variable-power lens group 3 and the compensating lens group 4 , and the adjustment component includes a first linear guide rail 22 , a second linear guide rail 23 , a cam shaft 24 and a sliding guide pin 25 .

[0030] The zoom lens group 3 is slidably mounted on the second linear guide rail 23, and the compensating lens group 4 is slidably mounted on the first linear guide rail 22. Both the zoom lens group 3 and the compensating lens group 4 are provided with sliding guide pins 25, which are connected to the cam shaft 24, and the cam shaft 24 is driven by a motor.

[0031] An adjustment component is also provided outside the focusing lens group 5 , and the position of the focusing component 5 is adjusted through the cooperation of the third linear guide rail, the cam shaft 24 and the sliding guide pin 25 .

[0032] An inspection port is also provided on the main frame 9, and a cover plate 27 matching the inspection port is provided inside the inspection port. A circular shielding sealing strip 26 is provided between the contact surface between the cover plate 27 and the inspection port. The cover plate 27 is fixed to the main frame 1 by screws 28, and a circular hole for the screws 28 to pass through is provided on the cover plate 27. The inspection port is arranged in a stepped manner, and a threaded hole for the screws 28 to be threadedly connected is provided on the step surface.

[0033] The working principle of the utility model is:

[0034] The entire sealed optical cabin 2 is regarded as a cutoff waveguide with a circular cross section. The strong electromagnetic waves are attenuated inside the optical cabin. For the waveguide attenuation of a circular cross section: A1 = 32L / D, where A is the attenuation in dB, L is the length of the cutoff waveguide in cm, and D is the inner diameter of the cutoff waveguide in cm. Since the optical cabin cannot be a circular hole with the same inner diameter, the waveguide attenuation of the entire optical cabin is: A = A1 + A2 + A3 + A4 + ...

[0035] The first refractor group 6, the folding frame 7, the second refractor group 12, the rear lens group 13, and the grid filter 14 realize the folding of light, and the internal channel plays the role of a cutoff waveguide. The cutoff frequency of the circular cutoff waveguide is: f c =17.6×10 9 / D, where f c is the cut-off frequency in Hz, and D is the inner diameter of the cut-off waveguide in cm. Usually the frequency f of interest is required max To be much lower than the cutoff frequency of the cutoff waveguide, f c Greater than 5 times f max Considered feasible

[0036] The optical system for infrared imaging includes, from the object plane to the image plane, a front lens group 1, a variable-power compensation lens group 3, 4, a focusing lens group 5, a first refraction lens group 6, a second refraction lens group 12, a rear lens group 13, and an image plane of an infrared detector 16. The imaging light beam 18 from the object side passes through the front lens group 1 in sequence to form a parallel light beam, passes through the variable-power lens group 3, the compensation lens group 4, and the focusing lens group 5 to adjust the image height and focal length, and then passes through the first refraction lens group 6 and the second refraction lens group 12 to return twice, and then reaches the rear lens group 13 and is imaged onto the focal plane of the infrared detector 16.

[0037] The working band of the infrared thermal imager optical system is 3.7μm~4.8μm, the focal length of small field of view is f1, the focal length of large field of view is f2, the system zoom ratio is: Г=f1 / f2; the zoom ratio range of the system is 1<Г≤10; the F number range of the infrared system is: 1.0≤F / #≤4;

[0038] When the zoom lens group 3 and the compensating lens group 4 are close to each other, the field of view decreases, the focal length value increases, and the closest position is a small field of view. Conversely, when the zoom lens group 3 and the compensating lens group 4 are far away from each other, the field of view increases, the focal length value decreases, and the distance between the zoom lens group 3 and the compensating lens group 4 is the farthest, which is a large field of view.

[0039] The forward and backward movement of the focusing lens group 5 can compensate for the image plane movement caused by the thermal expansion and contraction of the material at high and low temperatures of the entire optical system and the focusing operation for targets at different imaging distances; it can achieve imaging in the working temperature range of -40°C to +65°C and imaging requirements in the imaging object distance range of 10 meters to infinity, with a stable optical axis and an unchanged image plane position.

[0040] The rear lens group 13 is used for secondary imaging, to extend the total length of the optical system, and to change the coordinate relationship of the image and object. The infrared detector 16 is mainly used to collect light, and convert the collected light signal into an electrical signal under given conditions, output analog video, and realize A / D conversion, signal filtering and noise reduction, image enhancement and other functions through the internal circuit module 17, and output in the form of digital video, which is transmitted to the system assembly through the optical fiber 10.

[0041] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A strong electromagnetic resistant infrared thermal imager structure, comprising a main frame (9), characterized in that: An optical cabin (2) is provided on one side of the bottom of the main frame (9); a turning frame (7) is connected through the top of the tail end of the optical cabin (2); a rear mirror group (19) is fixedly connected to the tail end of the turning frame (7); a cutoff waveguide (21) is connected to the tail end of the rear mirror group (19); the cutoff waveguide (21) is connected to the optical window of the infrared detector (16); an electromagnetic shielding tape (15) is wrapped around the outside of the connection between the rear mirror group (19) and the cutoff waveguide (21); and a magnetic shielding tape (15) is arranged on the inside of the tail end of the turning frame (7). A rear lens group (13) is installed, a first refraction lens group (6) and a second refraction lens group (12) are installed at the inlet end and the turning point of the turning frame (7), respectively, the second refraction lens group (12) corresponds to the rear lens group (13), a variable magnification lens group (3), a compensation lens group (4) and a focusing lens group (5) are installed in sequence at the optical engine cabin (2) corresponding to the first refraction lens group (6), a front lens group (1) is installed at the port of the optical engine cabin (2) corresponding to the variable magnification lens group (3), and a grid filter (14) is placed on the end surface of the rear lens group (19).

2. The structure of the infrared thermal imager against strong electromagnetic fields according to claim 1, characterized in that: The infrared detector (16) is externally connected to an internal circuit module (17); corresponding connection ports of the internal circuit module (17) are respectively connected to a power filter (8) and an output optical fiber (10) via internal connection lines (11); the output optical fiber (10) penetrates and is fixedly connected to the upper portion of the other side of the main frame (9); and the power filter (8) is fixedly mounted on the lower side wall of the other side of the main frame (9).

3. The structure of the infrared thermal imager against strong electromagnetic fields according to claim 1, characterized in that: An external threaded joint is provided on the end surface of the rear mirror group (19), an internal thread is provided on the inner side of the cut-off waveguide tube (21), the cut-off waveguide tube (21) is threadedly connected to the rear mirror group (19), and the grid filter (14) is clamped and fixed between the cut-off waveguide tube (21) and the rear mirror group (19).

4. The structure of the infrared thermal imager against strong electromagnetic fields according to claim 1, characterized in that: An adjustment component is provided between the variable-power lens group (3) and the compensating lens group (4), and the adjustment component comprises a first linear guide rail (22), a second linear guide rail (23), a cam shaft (24) and a sliding guide pin (25).

5. The strong electromagnetic resistant infrared thermal imager structure according to claim 4, characterized in that: The variable power lens group (3) is slidably mounted on the second linear guide rail (23), and the compensating lens group (4) is slidably mounted on the first linear guide rail (22). Both the variable power lens group (3) and the compensating lens group (4) are provided with sliding guide pins (25), and the sliding guide pins (25) are connected to the cam shaft (24).

6. The structure of the infrared thermal imager resistant to strong electromagnetic fields according to claim 1, characterized in that: The main frame (9) is also provided with an inspection opening, and a cover plate (27) matching the inspection opening is provided inside the inspection opening, a circular shielding sealing strip (26) is provided between the contact surface between the cover plate (27) and the inspection opening, and the cover plate (27) is fixedly mounted to the main frame (9) by screws (28).

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