Multiband integrated optical system suitable for multi-target synchronous distance measurement

Abstract

The invention discloses a multiband integrated optical system suitable for multi-target synchronous distance measurement, which is characterized in that an incident beam is refracted into a parallel beam through a common telescopic system, then a first spectroscope reflects a laser beam in the parallel beam to a laser distance measurement unit, and meanwhile, an infrared beam is transmitted to a second spectroscope. The second spectroscope reflects a medium-wave infrared light beam from the first spectroscope to the medium-wave turning reflector, and the medium-wave turning reflector guides the light beam to the medium-wave relay optical system and finally focuses the light beam to the medium-wave infrared detector. Meanwhile, the long-wave infrared light beam directly penetrates through the second spectroscope, enters the long-wave relay optical system and is focused to the long-wave infrared detector. Through the two independent detection channels, the equivalent infrared radiance differences of all targets in middle and long wave bands in the field of view are captured at the same time, and infrared passive distance measurement is completed for multiple targets in the field of view according to the differences, so that the distance measurement efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of multi - band optical systems, and particularly to a multi - band integrated optical system suitable for multi - target synchronous ranging. Background Art

[0002] Traditional multi - target ranging optical solutions generally rely on the one - by - one active illumination mode of "laser ranging and infrared axis alignment". This mode requires the optical axes of the infrared imaging optical system and the laser ranging optical system to be precisely calibrated in advance. In actual operation, when multiple targets appear in the field of view of the infrared imaging system, the traditional method is to rotate the turntable carrier to align the optical axis of the infrared imaging system with each target to be measured one by one. Subsequently, the laser ranging optical system will actively illuminate the target to achieve ranging, and the whole process needs to be repeated until all targets are measured. However, this target switching method relying on the rotation of the turntable carrier has obvious defects, including slow switching speed and easy loss of targets. These problems are particularly prominent in dynamic or rapidly changing environments.

[0003] In the prior art, the patent with the publication number CN112526531B discloses: a dual - field - of - view infrared imaging system with multi - target laser ranging function. The core innovation of this patent is to integrate the laser and infrared dual - bands into a common optical path optical system and share a front - end off - axis two - mirror telescope. It reduces the manual calibration link of the dual optical axes when installing and adjusting the infrared and laser optical systems in the traditional scheme. For the alignment of the optical axis of the optical system with the target to be measured during ranging, this patent changes the alignment achieved by the rotation of the turntable carrier to the rapid swing of a scanning mirror added in the optical path. At the same time, the large and small field - of - view switching of the optical system is completed by the cutting - in and cutting - out of a field - of - view switching mirror group added in the optical path, realizing ranging for a limited number of targets within two fixed fields of view.

[0004] However, this patent still belongs to the one - by - one active illumination ranging method of "laser ranging and infrared axis alignment", with low ranging efficiency. In addition, due to the fixed ranging field of view, the number of ranging targets is limited, and it is impossible to range dynamic targets. Summary of the Invention

[0005] Embodiments of the present invention provide a multi - band integrated optical system suitable for multi - target synchronous ranging, which solves the technical problems of low ranging efficiency and limited number of ranging targets in the prior art, realizes the spectral integration of multiple bands, and can range multiple static and dynamic targets within the panoramic field of view.

[0006] In a first aspect, to solve the above - mentioned technical problems, embodiments of the present invention provide the following technical solutions:

[0007] A multi-band integrated optical system suitable for multi-target synchronous ranging, comprising:

[0008] A telescope system, a first beam splitter, a second beam splitter and an infrared detection mechanism are arranged in sequence from the object side to the image side along the main optical path; a laser distance measuring unit is arranged below the first beam splitter;

[0009] The telescope system is used to refract the incident light beam and emit a parallel light beam to the first beam splitter;

[0010] The angle between the normal line of the first beam splitter and the main light path is 45°; the first beam splitter reflects the laser beam in the parallel light beam to the laser ranging unit, and transmits the infrared beam in the parallel light beam to the second beam splitter;

[0011] The infrared detection mechanism comprises a medium-wave folding reflector, a medium-wave relay optical system and a medium-wave infrared detector arranged in sequence on a first optical path, and a long-wave relay optical system and a long-wave infrared detector arranged in sequence on a second optical path;

[0012] The angle between the normal line of the second beam splitter and the main optical path is 45°. The second beam splitter reflects the medium-wave infrared beam to the medium-wave folding reflector. The angle between the medium-wave folding reflector and the first optical path is 45°. The medium-wave folding reflector transmits the medium-wave infrared beam to the medium-wave relay optical system. The medium-wave relay optical system focuses the medium-wave infrared beam onto the medium-wave infrared detector. The second beam splitter transmits the long-wave infrared beam to the long-wave relay optical system. The long-wave relay optical system focuses the long-wave infrared beam onto the long-wave infrared detector.

[0013] From the medium-wave infrared detector and the long-wave infrared detector, the difference in equivalent infrared radiation of all targets to be measured in the medium-wave and long-wave bands is obtained, and infrared passive ranging is performed based on the difference.

[0014] Furthermore, the telescope system includes a primary mirror, a secondary mirror and a tertiary mirror arranged in sequence along the main optical path. The primary mirror is a concave mirror, which is used to reduce the aperture of the incident light beam and reflect it to the secondary mirror; the secondary mirror reflects the incident light beam to the tertiary mirror, and emits a parallel light beam to the first beam splitter through the tertiary mirror.

[0015] Furthermore, a secondary reflector and a scanning compensation reflector are also included between the third mirror and the first beam splitter;

[0016] The angle between the normal line of the secondary reflector and the main optical path is 45°. The secondary reflector can swing periodically in the left and right directions around the vertical axis of its mirror surface to align the optical axis of the infrared optical system with the target to be measured. The secondary reflector reflects the parallel light beam to the circumferential scanning compensation reflector.

[0017] The included angle between the normal of the weekly scanning compensating mirror and the main optical path is 45°. The weekly scanning compensating mirror can swing periodically in the pitching direction around the horizontal axis of its mirror surface to compensate for the image plane drift generated when the weekly rotating vehicle rotates; the weekly scanning compensating mirror reflects the parallel light beam to the first beam splitter.

[0018] Further, the weekly scanning compensating mirror is arranged at the exit pupil position of the telescopic system.

[0019] Further, the swinging angle range of the secondary mirror is from -1° to +1°.

[0020] Further, the swinging angle range of the weekly scanning compensating mirror is from -3° to +3°.

[0021] Further, an optical axis reference unit is also included. The optical axis reference unit is arranged at the bottom of the primary mirror. The optical axis reference unit includes a plurality of different infrared light sources, and the output end of each infrared light source faces the light receiving surface of the primary mirror; the light axis of the infrared optical system and the laser optical system is corrected by the light beam emitted by the optical axis reference unit.

[0022] Further, a vacuum tube is also included. The vacuum tube is arranged at the real focus between the secondary mirror and the tertiary mirror.

[0023] Further, a third beam splitter, a laser relay optical system and a laser optical axis detection unit are also included;

[0024] The third beam splitter is arranged between the first beam splitter and the laser ranging unit. The third beam splitter reflects the laser beam with the first wavelength in the laser beam to the laser relay optical system. The laser relay optical system focuses the laser beam with the first wavelength on the optical axis detection unit to correct the alignment of the laser optical system optical axis to the target;

[0025] The third beam splitter transmits the laser beam with the second wavelength in the laser beam to the laser ranging unit for laser ranging.

[0026] Further, a laser yaw reflecting mirror group is also included, which is arranged between the first beam splitter and the third beam splitter,

[0027] The laser yaw reflecting mirror group includes a pitching yaw reflecting mirror and an azimuth yaw reflecting mirror. The pitching yaw reflecting mirror can swing periodically in the pitching direction around the horizontal axis of its mirror surface; the azimuth yaw reflecting mirror can swing periodically in the left - right direction around the vertical axis of its mirror surface; it is used to correct the alignment of the laser optical system optical axis to the target to be measured.

[0028] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0029] In the present invention, by sharing a telescopic system, an incident light beam is refracted into a parallel light beam and directed towards a first beam splitter. The first beam splitter is responsible for reflecting the laser beam in the parallel light beam to the laser ranging unit below, while transmitting the infrared light beam to a second beam splitter. Thus, the functions of laser active ranging and infrared passive ranging are integrated into one. In the infrared detection part, it is divided into two detection channels, namely the medium-wave and long-wave channels. The second beam splitter is also configured at an angle of 45°, reflecting the medium-wave infrared light beam from the first beam splitter to a medium-wave folding mirror, and the medium-wave folding mirror then directs the light beam to a medium-wave relay optical system at an angle of 45° and finally focuses it onto a medium-wave infrared detector. At the same time, the long-wave infrared light beam directly passes through the second beam splitter, enters the long-wave relay optical system, and is focused onto a long-wave infrared detector. Through these two independent detection channels, the system can simultaneously capture the equivalent infrared radiance differences of all targets in the field of view in the medium and long wavelength bands, and complete infrared passive ranging for multiple targets in the field of view based on these differences, thereby improving the ranging efficiency. Description of the Drawings

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the following drawings 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.

[0031] Figure 1 Schematic diagram of a multi-band integrated optical system applicable to multi-target synchronous ranging provided by the present invention;

[0032] Figure 2 External shape structure and installation position of the vacuum tube in the present invention;

[0033] Figure 3a Side view of a medium-wave infrared imaging system with an off-axis three-reflection telescopic system in the present invention;

[0034] Figure 3b Axonometric view of a medium-wave infrared imaging system with an off-axis three-reflection telescopic system in the present invention;

[0035] Figure 4 Medium-wave infrared light path tracing diagram of a medium-wave infrared imaging system with an off-axis three-reflection telescopic system in the present invention;

[0036] Figure 5 Spot diagram and MTF diagram of a medium-wave infrared imaging system with an off-axis three-reflection telescopic system in the present invention;

[0037] Figure 6a Side view of a long-wave infrared imaging system with an off-axis three-reflection telescopic system in the present invention;

[0038] Figure 6bAxonometric view of the long-wave infrared imaging system with an off-axis three-mirror telescopic system in the present invention;

[0039] Figure 7 Optical path tracing diagram of the long-wave infrared in the long-wave infrared imaging system with an off-axis three-mirror telescopic system in the present invention;

[0040] Figure 8 Spot diagram and MTF diagram of the long-wave infrared imaging system with an off-axis three-mirror telescopic system in the present invention;

[0041] Figure 9 Optical path tracing diagram of the laser relay optical system in the present invention;

[0042] Figure 10 Spot diagram and MTF diagram of the laser relay optical system in the present invention;

[0043] Figure 11 Schematic diagram of the swing in the left-right direction along the vertical axis of the mirror surface in the present invention;

[0044] Figure 12 Schematic diagram of the swing in the pitch direction along the horizontal axis of the mirror surface in the present invention.

[0045] Reference numerals: 1, optical axis reference unit; 2, telescopic system; 201, primary mirror; 202, secondary mirror; 203, tertiary mirror; 3, secondary reflector; 4, circumferential scan compensation reflector; 5, first beam splitter; 6, second beam splitter; 7, mid-wave folding reflector; 8, mid-wave relay optical system; 801, first mid-wave objective lens; 802, second mid-wave objective lens; 803, third mid-wave objective lens; 804, fourth mid-wave objective lens; 805, fifth mid-wave objective lens; 806, sixth mid-wave objective lens; 9, mid-wave infrared detector; 10, long-wave infrared detector; 11, long-wave relay optical system; 1101, first long-wave objective lens; 1102, second long-wave objective lens; 1103, third long-wave objective lens; 1104, fourth long-wave objective lens; 1105, fifth long-wave objective lens; 1106, sixth long-wave objective lens; 12, laser yaw reflector group; 1201, pitch yaw reflector; 1202, azimuth yaw reflector; 13, laser relay optical system; 1301, first laser objective lens; 1302, second laser objective lens; 1303, third laser objective lens; 14, third beam splitter; 15, laser optical axis detection unit; 16, laser ranging unit; 17, vacuum tube; 18, long-wave folding reflector; 1701, front optical window; 1702, rear optical window. Detailed implementation manners

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and illustrated herein generally can be arranged and designed in a variety of different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0048] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, in the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "first", "second", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0049] In the embodiments of the present invention, there is provided a multi-band integrated optical system applicable to multi-target synchronous ranging as Figure 1 shown, including:

[0050] A telescopic system 2, a first beam splitter 5, a second beam splitter 6, and an infrared detection mechanism arranged in sequence from the object side to the image side along the main optical path direction; a laser ranging unit 16 is provided below the first beam splitter 5;

[0051] The telescopic system 2 is used to refract the incident beam and emit a parallel beam to the first beam splitter 5.

[0052] Specifically:

[0053] The telescopic system 2 adopts an off-axis three-mirror telescopic system 2, which is located at the forefront of the main optical path. As Figure 2 shown, it includes a primary mirror 201, a secondary mirror 202, and a tertiary mirror 203 arranged in sequence along the main optical path direction; the primary mirror 201 is a concave mirror, which receives the incident beam from the object side, refracts it to reduce the clear aperture of the incident beam, and reflects it onto the secondary mirror 202; the secondary mirror 202 reflects the incident beam onto the tertiary mirror 203, and the tertiary mirror 203 emits a parallel beam to the first beam splitter 5. Its purpose is to reduce the clear aperture of the incident multi-band and large-aperture beam within a certain field of view and emit it as parallel light. This process involves the compression of the beam aperture and the adjustment of the optical path to meet the subsequent beam splitting and detection requirements.

[0054] In addition, since the single-band laser emitted and received by the laser ranging unit 16 needs to pass through the front telescopic system 2, it is extremely easy to ionize the primary real image plane existing between the secondary mirror 202 and the tertiary mirror 203 of the telescopic system 2, thereby weakening the laser energy and affecting the ranging operation distance. Therefore, a vacuum tube 17 is arranged at the real focus between the secondary mirror 202 and the tertiary mirror 203, which can ensure that the optical real focus cannot interfere with the laser. Among them, the materials of the front optical window 1701 and the rear optical window 1702 of the vacuum tube 17 are both ZnS, the material of the wall of the vacuum tube 17 is quartz, and the vacuum tube 17 is glued and formed and its interior is evacuated to ensure that the vacuum degree is below 10-5 Pa.

[0055] The first beam splitter 5 is located behind the telescopic system 2, and the included angle between its normal line and the main optical path is 45°. The function of the first beam splitter 5 is to reflect the laser beam in the parallel beam to the laser ranging unit 16, and at the same time transmit the infrared beam to the second beam splitter 6. This beam splitting design allows the system to process laser and infrared signals simultaneously, improving the multi-band processing ability of the system. Among them, the laser ranging unit 16 is used for laser active illumination ranging, and this device is a mature technology product in the industry and will not be elaborated here.

[0056] The infrared detection mechanism is designed to detect and process the mid-wave infrared beam and the long-wave infrared beam respectively. Therefore, the second beam splitter 6 is used to divide the main optical path into two sub-optical paths, namely the first optical path and the second optical path. Specifically, the first optical path includes a mid-wave folding mirror 7, a mid-wave relay optical system 8 and a mid-wave infrared detector 9 arranged in sequence; the second optical path includes a long-wave relay optical system 11 and a long-wave infrared detector 10 arranged in sequence.

[0057] The normal line of the second beam splitter 6 forms an included angle of 45° with the main optical path. The second beam splitter 6 reflects the mid-wave infrared beam to the mid-wave folding mirror 7, and the included angle between the mid-wave folding mirror 7 and the first optical path is 45°. The mid-wave folding mirror 7 reflects the mid-wave infrared beam to the mid-wave relay optical system 8, and the mid-wave relay optical system 8 focuses the mid-wave infrared beam on the mid-wave infrared detector 9; the second beam splitter 6 transmits the long-wave infrared beam to the long-wave folding mirror 18, and the long-wave folding mirror 18 reflects the long-wave infrared beam to the long-wave relay optical system 11, and the long-wave relay optical system 11 focuses the long-wave infrared beam on the long-wave infrared detector 10.

[0058] Among them, as Figure 3a and Figure 3bAs shown, when the medium-wave relay optical system 8 receives the medium-wave infrared beam, the medium-wave relay optical system 8 sequentially passes through the refraction and focusing effects of the first medium-wave objective lens 801, the second medium-wave objective lens 802, the third medium-wave objective lens 803, the fourth medium-wave objective lens 804, the fifth medium-wave objective lens 805 and the sixth medium-wave objective lens 806, and finally couples the optical image plane to the target surface of the medium-wave infrared detector 9. Thus, the medium-wave infrared image of each target in the field of view is formed, and the equivalent infrared radiance of the target in the medium-wave band is obtained.

[0059] As shown in FIG6 , when the long-wave relay optical system 11 receives a long-wave infrared beam, the long-wave relay optical system 11 sequentially refracts and focuses the beam through the first long-wave objective lens 1101, the second long-wave objective lens 1102, the third long-wave objective lens 1103, the fourth long-wave objective lens 1104, the fifth long-wave objective lens 1105, and the sixth long-wave objective lens 1106, and finally couples the optical image plane to the target surface of the long-wave infrared detector 10, forming a long-wave infrared image of each target in the field of view, and obtaining the equivalent infrared radiance of the target in the long-wave band.

[0060] The difference in equivalent infrared radiance of all targets to be measured in the medium-wave and long-wave bands is obtained from the medium-wave infrared detector 9 and the long-wave infrared detector 10, and infrared passive ranging is performed based on the difference.

[0061] Among them, regarding the calculation of passive ranging, the mathematical model of passive ranging can be established by using the infrared radiation transmission equation and the detector response model when the target radiance, atmospheric transmittance and detector performance are known. By solving this model, the distance between the target to be measured and the detector can be obtained.

[0062] In some embodiments of the present invention, a secondary reflector 3 and a sweep compensation reflector 4 are further included between the third mirror 203 and the first beam splitter 5; the angle between the normal of the secondary reflector 3 and the main light path is 45°, and the secondary reflector 3 can swing periodically in the left and right directions around the vertical axis of its mirror surface, such as Figure 11 As shown, it is used to calibrate the optical axis of the infrared optical system to align with the target to be measured; the secondary reflector 3 reflects the parallel light beam to the sweep compensation reflector 4;

[0063] Among them, the secondary reflector 3 can reflect light beams in the range of 0.85μm to 10.5μm. The secondary precision stabilizing reflector can periodically swing around the vertical axis of its mirror surface in the left and right directions, and the swing angle range is -1° to +1°, which is used to align the optical axis of the infrared (medium wave, long wave) optical system with the target to be measured. In addition, since the peripheral gear is used as a primary stabilizing axis unit, the stabilization resolution is low and the optical axis of the optical system cannot be precisely stabilized. Therefore, the secondary reflector 3 is used as a secondary stabilizing axis unit and is also used to precisely stabilize the optical axis of the optical system.

[0064] The included angle between the normal line of the circumferential scan compensating mirror 4 and the main optical path is 45°. The circumferential scan compensating mirror 4 reflects the parallel light beam to the first beam splitter 5. The circumferential scan compensating mirror 4 can swing periodically in the pitch direction around the horizontal axis of its mirror surface, as Figure 12 shown. The swing angle range is from -3° to +3°, which is used to compensate for the image plane drift generated when the circumferential rotating vehicle rotates. Thus, it is ensured that during the exposure of the medium and long wave infrared detectors, the optical axes of the medium and long wave infrared optical systems are stationary relative to the object scene, and medium and long wave infrared detection imaging of static and dynamic targets within the panoramic field of view (horizontal N×360°, pitch -5° to 14°) is achieved.

[0065] Furthermore, the circumferential scan compensating mirror 4 is located behind the secondary mirror 3, and the circumferential scan compensating mirror 4 is arranged at the exit pupil position of the telescopic system 2. At this time, the size of the circumferential scan compensating mirror 4 is the smallest. This is beneficial to reducing the complexity and cost of the system, while improving the compactness and overall performance of the optical system.

[0066] Furthermore, it further includes an optical axis reference unit 1, which can emit composite laser with any wavelength within the range of 3.7μm to 4.8μm and 0.76μm to 3μm. The optical axis reference unit 1 is a mature product in the industry and will not be elaborated here. The optical axis reference unit 1 is arranged at the bottom of the main mirror 201. The optical axis reference unit 1 includes a plurality of different infrared light sources, and the output end of each infrared light source faces the light receiving surface of the main mirror 201. The optical axes of the infrared optical system and the laser optical system are corrected by the light beam emitted by the optical axis reference unit 1.

[0067] Among them, the setting of the optical axis reference unit 1 is mainly to achieve accurate ranging of multiple highly maneuverable targets within the panoramic field of view. In this process, the optical axis reference unit 1 plays a key role. It is responsible for correcting and aligning the optical axes of the medium wave and long wave infrared optical systems with the optical axis of the laser optical system to ensure that they can jointly point to and lock the target. Specifically, the optical axis reference unit 1 emits composite laser with wavelengths of 4μm and 0.975μm, which successively passes through the telescopic system 2, the secondary mirror 3, the circumferential scan compensating mirror 4, and then is split by the first beam splitter 5. The laser with a wavelength of 4μm is transmitted by the first beam splitter 5, and the laser with a wavelength of 0.975μm is reflected.

[0068] When aligning the optical axis of the long-wave infrared optical system, the laser with a wavelength of 4 μm transmitted by the first beam splitter 5 is incident on the second beam splitter 6, and after being reflected by the second beam splitter 6 and the mid-wave infrared folding mirror in sequence, it is incident on the mid-wave relay optical system 8 as parallel light. Through the refraction and focusing effect of the mid-wave relay optical system 8, a point image is formed on the target surface of the mid-wave infrared detector 9. The mid-wave infrared beam emitted by the front-end telescopic system 2 forms an image on the target surface of the mid-wave infrared detector 9, and there is a center position of the infrared image plane. Among them, the secondary mirror 3 is a moving part, and the secondary mirror can swing periodically in the left-right direction around the vertical axis of its mirror surface, and the swing angle range is from -1° to +1° to ensure that the aforementioned laser point image is always located at the center position of the infrared image plane, so as to realize the alignment of the optical axis of the mid-wave infrared optical system. By means of structural alignment, it is ensured that the optical axes of the mid-wave and long-wave infrared optical systems are always parallel. When the optical axis of the mid-wave infrared optical system is aligned, the optical axis of the long-wave infrared optical system is also aligned.

[0069] Furthermore, it also includes a third beam splitter 14, a laser relay optical system 13 and a laser optical axis detection unit 15;

[0070] The third beam splitter 14 is arranged between the first beam splitter 5 and the laser ranging unit 16. The third beam splitter 14 reflects the laser beam with the first wavelength in the laser beam to the laser relay optical system 13, and the laser relay optical system 13 focuses the laser beam with the first wavelength on the optical axis detection unit to correct the alignment of the optical axis of the laser optical system with the target; the third beam splitter 14 transmits the laser beam with the second wavelength in the laser beam to the laser ranging unit 16 for laser ranging.

[0071] In addition, the laser yaw mirror group 12 is arranged between the first beam splitter 5 and the third beam splitter 14, and it includes a pitch yaw mirror 1201 and an azimuth yaw mirror 1202. The pitch yaw mirror 1201 can swing periodically in the pitch direction around the horizontal axis of its mirror surface, such as Figure 12 ; the azimuth yaw mirror 1202 can swing periodically in the left-right direction around the vertical axis of its mirror surface, such as Figure 11 ; for correcting the alignment of the optical axis of the laser optical system with the target to be measured.

[0072] When aligning the optical axis of the laser optical system, as Figure 1 and Figure 9 shown, the above parameters are still used: the composite laser with wavelengths of 4 μm and 0.975 μm is emitted by the optical axis reference unit 1, and passes through the telescopic system 2, the secondary mirror 3, and the circumferential scan compensation mirror 4 in sequence, and then is split by the first beam splitter 5. The laser with a wavelength of 4 μm is transmitted by the first beam splitter 5, and the laser with a wavelength of 0.975 μm is reflected. The alignment principle is as follows:

[0073] The laser with a wavelength of 0.975 μm, which is reflected by the first beam splitter 5, enters the laser yaw mirror group 12. After being reflected by the third beam splitter 14, it enters the laser relay optical system 13 as parallel light. Through the refraction and focusing effect of the laser relay optical system 13, a point image is formed on the target surface of the laser optical axis detection unit 15. The laser optical axis detection unit 15 detects the deviation between the optical axis of the laser optical system and the optical axis calibration reference point, and controls the laser yaw mirror group 12 to swing in two-dimensional directions around the normal of its mirror surface pointing, with the swing angle range from -1° to +1°, to complete the optical axis calibration of the laser optical system.

[0074] Among them, as Figure 9 shown, after receiving the parallel laser beam, the laser relay optical system 13 sequentially refracts and focuses the laser beam through the first laser objective lens 1301, the second laser objective lens 1302, and the third laser objective lens 1303 inside it, and finally couples the optical image plane to the laser optical axis detection unit 15 for calibrating the alignment of the optical axis of the laser optical system to the target.

[0075] The following is an explanation in combination with data, specifically as follows:

[0076] The laser wavelengths are: 0.975 μm and 4 μm composite laser and 1.064 μm single-wavelength laser. Medium-wave relay optical system: The band range is 3.7 μm - 4.8 μm, the F number is 2, and the field of view is the paraxial image height of 6.5 mm. Long-wave relay optical system: The band range is 7.7 μm - 9.5 μm, the F number is 2, and the field of view is the paraxial image height of 6.5 mm. The first beam splitter transmits the infrared bands of 3.7 μm - 4.8 μm and 7.7 μm - 9.5 μm, transmits the laser wavelength of 4 μm, and reflects the laser wavelengths of 0.975 μm and 1.064 μm; the second beam splitter transmits the long-wave infrared of 7.7 μm - 9.5 μm and reflects the medium-wave infrared of 3.7 μm - 4.8 μm; the third beam splitter transmits the laser with a wavelength of 1.064 μm and reflects the laser wavelength of 0.975 μm.

[0077] Table 1 Data sheet of the medium-wave infrared optical system of the telescopic system

[0078]

[0079]

[0080] Among them, the primary mirror 201 and the secondary mirror 202 of the telescopic system 2 are both aspheric surfaces, the tertiary mirror 203 is a freeform surface, and the aspheric data is shown in Table 2. Preferably, the reflecting mirror materials are all aluminum alloy, and the structural frame is also aluminum alloy. The thermal expansion coefficients of the two match, ensuring that the system has a wide operating temperature range, reaching from -40°C to +60°C. At the same time, it is beneficial to the lightweight design of the system. There is a primary real image plane between the secondary mirror 202 and the tertiary mirror 203. A vacuum tube 17 is set at the primary real image plane. The materials of the front optical window 1701 and the rear optical window 1702 of the vacuum tube are both ZnS, and the side wall material of the vacuum tube 17 is quartz, ensuring that the vacuum degree is below 10-5 Pa. A total of 4 aspheric surfaces are set on the second mid-wave objective lens 802, the fourth mid-wave objective lens 804, and the fifth mid-wave objective lens 805 in the mid-wave relay optical system 8, and the aspheric data is shown in Table 2.

[0081] Table 2 Aspheric Data Table

[0082]

[0083]

[0084] Based on the relevant parameters of the above mid-wave infrared optical system, a mid-wave infrared optical system with telescopic function is configured. When performing panoramic reverse scanning, its optical performance is displayed through a spot diagram and a modulation transfer function (MTF) diagram, specifically as Figure 5 shown. It can be seen from this that the optical performance indicators of this system have reached the expected usage standards.

[0085] For the long-wave infrared optical system, the following data is adopted:

[0086] Table 3 Data Table of the Long-wave Infrared Optical System of the Telescopic System

[0087]

[0088]

[0089] A total of 2 aspheric surfaces are set on the first long-wave objective lens 1101 and the fourth mid-wave objective lens 1104 in the long-wave relay optical system 11, and the aspheric data is shown in Table 4.

[0090] Table 4 Aspheric Data Table

[0091]

[0092] Based on the relevant parameters of the above long-wave infrared optical system, a mid-wave infrared optical system with telescopic function is configured. When performing panoramic reverse scanning, its optical performance is displayed through a spot diagram and a modulation transfer function (MTF) diagram, specifically as Figure 8 shown. It can be seen from this that the optical performance indicators of this system have reached the expected usage standards.

[0093] For laser calibration, the following data is used:

[0094] Table 5 Data Sheet of Laser Relay Optical System for Calibrating the Optical Axis of Laser Optical System

[0095]

[0096] Based on the relevant parameters of the above laser calibration, the spot diagram and MTF diagram of the laser optical system of the integrated telescopic system in the panoramic reverse scanning state are as Figure 10 shown. It can be seen therefrom that the optical performance indicators of this system have reached the expected usage standards.

[0097] In summary, a multi-band integrated optical system applicable to multi-target synchronous ranging provided by the present invention receives and refracts the incident light beam through the telescopic system 2, and reduces the clear aperture of the large-aperture light beam and emits it in the form of parallel light through the off-axis three-reflection structure in the telescopic system 2; subsequently, the parallel light beam is separated by the first beam splitter 5, wherein the laser beam is reflected to the laser ranging unit 16 for laser ranging, while the infrared light beam continues to transmit to the second beam splitter 6 and is further divided into medium-wave and long-wave infrared light beams, which are respectively focused on the infrared detector by the corresponding relay optical systems to form images; meanwhile, through the periodic swinging of the secondary mirror 3 and the panoramic scanning compensation mirror 4, the optical axis of the infrared optical system is corrected and stabilized to ensure the accurate detection of multiple targets within the panoramic field of view. Cooperating with the laser ranging unit 16, the present invention has the advantages of high ranging efficiency and multiple ranging methods.

[0098] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0099] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A multi-band integrated optical system suitable for multi-target synchronous ranging, characterized in that: It includes a telescope system, a first beam splitter, a second beam splitter and an infrared detection mechanism which are arranged in sequence from the object side to the image side along the main optical path; a laser distance measuring unit is arranged below the first beam splitter; The telescopic system is used to refract the incident light beam and emit a parallel light beam to the first beam splitter; The angle between the normal line of the first beam splitter and the main light path is 45°; the first beam splitter reflects the laser beam in the parallel light beam to the laser ranging unit, and the first beam splitter transmits the infrared beam in the parallel light beam to the second beam splitter; The infrared detection mechanism comprises a medium-wave folding reflector, a medium-wave relay optical system and a medium-wave infrared detector arranged in sequence on a first optical path, and a long-wave relay optical system and a long-wave infrared detector arranged in sequence on a second optical path; The angle between the normal of the second beam splitter and the main optical path is 45°, the second beam splitter reflects the medium-wave infrared beam to the medium-wave folding reflector, the angle between the medium-wave folding reflector and the first optical path is 45°, the medium-wave folding reflector transmits the medium-wave infrared beam to the medium-wave relay optical system, and the medium-wave relay optical system focuses the medium-wave infrared beam onto the medium-wave infrared detector; the second beam splitter transmits the long-wave infrared beam to the long-wave relay optical system, and the long-wave relay optical system focuses the long-wave infrared beam onto the long-wave infrared detector; The difference in equivalent infrared radiance of all targets to be measured in the medium-wave and long-wave bands is obtained from the medium-wave infrared detector and the long-wave infrared detector, and infrared passive ranging is performed according to the difference.

2. The multi-band integrated optical system according to claim 1, characterized in that: The telescope system includes a primary mirror, a secondary mirror and a tertiary mirror which are sequentially arranged along the main optical path, wherein the primary mirror, the secondary mirror and the tertiary mirror form an off-axis three-mirror structure; the primary mirror is a concave mirror, which is used to reduce the aperture of an incident light beam and reflect it onto the secondary mirror; the secondary mirror reflects the incident light beam onto the tertiary mirror, and emits a parallel light beam to the first beam splitter through the tertiary mirror.

3. The multi-band integrated optical system according to claim 2, characterized in that: A secondary reflector and a periscopic compensation reflector are also included between the three mirrors and the first beam splitter; The angle between the normal of the secondary reflector and the main optical path is 45°. The secondary reflector can swing periodically in the left and right directions around the vertical axis of its mirror surface to align the optical axis of the infrared optical system with the target to be measured. The secondary reflector reflects the parallel light beam to the circumferential scanning compensation reflector. The angle between the normal of the circumferential scan compensating reflector and the main optical path is 45°. The circumferential scan compensating reflector can swing periodically in the pitch direction around the horizontal axis of its mirror surface to compensate for the image plane drift caused by the rotation of the circumferential transport gear; the circumferential scan compensating reflector reflects the parallel light beam to the first beam splitter.

4. The multi-band integrated optical system according to claim 3, characterized in that: The circumferential scanning compensation reflector is arranged at the exit pupil position of the telescopic system.

5. The multi-band integrated optical system according to claim 3, characterized in that: The swing angle range of the secondary reflector is from -1° to +1°.

6. The multi-band integrated optical system according to claim 3, characterized in that: The swing angle range of the circumferential scanning compensation reflector is from -3° to +3°.

7. The multi-band integrated optical system according to claim 2, characterized in that: It also includes an optical axis reference unit, which is arranged at the bottom of the main mirror. The optical axis reference unit includes a plurality of different infrared light sources, and the output end of each infrared light source is facing the light receiving surface of the main mirror. The light beam emitted by the optical axis reference unit corrects the optical axes of the infrared optical system and the laser optical system.

8. The multi-band integrated optical system according to claim 2, characterized in that: It also includes a vacuum tube, which is arranged at a real focus between the secondary mirror and the third mirror.

9. The multi-band integrated optical system according to any one of claims 1 to 8, characterized in that: Also includes a third beam splitter, a laser relay optical system and a laser optical axis detection unit; The third beam splitter is arranged between the first beam splitter and the laser distance measuring unit, and the third beam splitter reflects the laser beam of the first wavelength in the laser beam to the laser relay optical system, and the laser relay optical system focuses the laser beam of the first wavelength on the optical axis detection unit, so as to align the optical axis of the laser optical system with the target; The third beam splitter transmits the laser beam of the second wavelength in the laser beam to the laser ranging unit for laser ranging.

10. The multi-band integrated optical system according to claim 9, characterized in that: It also includes a laser deflection mirror group arranged between the first beam splitter and the third beam splitter, The laser yaw reflector group includes a pitch yaw reflector and an azimuth yaw reflector. The pitch yaw reflector can swing periodically in the pitch direction around the horizontal axis of its mirror surface; the azimuth yaw reflector can swing periodically in the left and right directions around the vertical axis of its mirror surface; and is used to calibrate the optical axis of the laser optical system to align with the target to be measured.

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