A tri-mode composite optical system

Abstract

This invention discloses a three-mode composite optical system, relating to the field of optical design, including an object plane, a primary reflector, a secondary reflector, a first beam splitter, a second beam splitter, a laser system, a visible light system, and a long-wave infrared system. Light emitted from the object plane is reflected by the secondary and primary reflectors to the first beam splitter, and then transmitted to the second beam splitter. The light then passes through the reflection path of the second beam splitter to form the laser system. Light emitted from the object plane is reflected by the secondary and primary reflectors to the first beam splitter, and then passes through the reflection path of the first beam splitter to form the visible light system. Light emitted from the object plane is reflected by the secondary and primary reflectors to the first beam splitter, and then transmitted through the first beam splitter to the second beam splitter. Finally, the light passes through the transmission path of the second beam splitter to form the long-wave infrared system. The system provided by this invention uses two beam splitters for beam splitting, reducing costs and having a wide range of applications.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical design, in particular to a three-mode composite optical system. BACKGROUND

[0002] The composite optical system is an important component of the composite seeker, which detects and tracks the infrared radiation of the target and receives the laser energy reflected by the target during the flight of the missile. The multi-mode composite optical system can obtain the information of multiple dimensions of the target, improve the anti-stealth, anti-interference and target recognition capabilities of the seeker, and enhance the perception and penetration capabilities of the missile to wide-area information. Since the multi-mode composite technology belongs to complex imaging, there are problems such as mode switching and multi-mode information fusion, and the system is complex, the number of parts is large, and the assembly and adjustment are difficult; therefore, a three-mode composite optical system is needed to overcome the problems in the prior art. SUMMARY

[0003] The purpose of the present application is to provide a three-mode composite optical system to solve the problems of mode switching difficulty, difficulty in multi-mode information fusion, system complexity, large number of parts and difficult assembly and adjustment in the prior art.

[0004] To achieve the above-mentioned purpose, the present application provides a three-mode composite optical system, which comprises an object plane, a main reflector, a secondary reflector, a first beam splitter, a second beam splitter, a laser system, a visible light system and a long-wave infrared system.

[0005] The light emitted by the object plane is reflected by the secondary reflector and the main reflector to the first beam splitter, and is transmitted to the second beam splitter, and the reflected light path through the second beam splitter forms the laser system.

[0006] The light emitted by the object plane is reflected by the secondary reflector and the main reflector to the first beam splitter, and the reflected light path through the first beam splitter forms the visible light system.

[0007] The light emitted by the object plane is reflected by the secondary reflector and the main reflector to the first beam splitter, and the transmitted light path through the second beam splitter forms the long-wave infrared system.

[0008] Preferably, the laser system comprises a first lens group, a first filter and a first detector; the light beam reflected on the second beam splitter is received by the first detector through the first lens group and the first filter; wherein the first lens group comprises a first lens, a second lens and a third lens arranged away from the second beam splitter in sequence.

[0009] Preferably, the first lens has a front and back curvature radius ranging from 67mm to 97mm and 10mm to 40mm, an optical thickness absolute value ranging from 12mm to 15mm, and an optical material of H-LAK5A; the second lens has a front and back curvature radius ranging from -35mm to -5mm and -64mm to -34mm, an optical thickness absolute value ranging from 3mm to 6mm, and an optical material of H-ZLAF76A; the third lens has a front and back curvature radius ranging from -5mm to 25mm and -3mm to 27mm, an optical thickness absolute value ranging from 4mm to 7mm, and an optical material of H-ZLAF90.

[0010] Preferably, the visible light system comprises a second lens group, a second filter, and a second detector; the light beam reflected by the first beam splitter is received by the second detector through the second lens group and the second filter; wherein the second lens group comprises a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged in sequence away from the first beam splitter.

[0011] Preferably, the fourth lens has a front and back curvature radius ranging from -74mm to -44mm and 69mm to 99mm, an optical thickness absolute value ranging from 6mm to 9mm, and an optical material of H-ZK50GT; the fifth lens has a front and back curvature radius ranging from -32mm to -2mm and -87mm to -57mm, an optical thickness absolute value ranging from 3mm to 6mm, and an optical material of H-ZLAF68B; the sixth lens has a front and back curvature radius ranging from 1mm to 31mm and -51mm to -21mm, an optical thickness absolute value ranging from 2mm to 5mm, and an optical material of H-ZF88GT; the seventh lens has a front and back curvature radius ranging from 95mm to 125mm and 3mm to 33mm, an optical thickness absolute value ranging from 3mm to 6mm, and an optical material of H-ZLAF68B; the eighth lens has a front and back curvature radius ranging from -91mm to -61mm and 44mm to 74mm, an optical thickness absolute value ranging from 3mm to 6mm, and an optical material of H-ZLAF50E; the ninth lens has a front and back curvature radius ranging from -33mm to -3mm and 44mm to 74mm, an optical thickness absolute value ranging from 12mm to 15mm, and an optical material of H-ZLAF68B.

[0012] Preferably, the long-wave infrared system comprises a third lens group, a third filter, and a third detector; the light beam transmitted on the second beam splitter is received by the third detector through the third lens group and the third filter; wherein the third lens group comprises a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens, and a fifteenth lens arranged in sequence away from the second beam splitter.

[0013] Preferably, the tenth lens has a front and back curvature radius ranging from 158mm to 188mm and from -559mm to -529mm, an optical thickness absolute value ranging from 8mm to 11mm, and an optical material of GERMANIUM; the eleventh lens has a front and back curvature radius ranging from 17mm to 47mm and from 7mm to 37mm, an optical thickness absolute value ranging from 2mm to 5mm, and an optical material of GERMANIUM; the twelfth lens has a front and back curvature radius ranging from 10mm to 40mm and from 22mm to 52mm, an optical thickness absolute value ranging from 2mm to 5mm, and an optical material of ZNSE; the thirteenth lens has a front and back curvature radius ranging from -24mm to 6mm and from -33mm to -3mm, an optical thickness absolute value ranging from 7mm to 10mm, and an optical material of GERMANIUM; the fourteenth lens has a front and back curvature radius ranging from 11mm to 41mm and from -110mm to -80mm, an optical thickness absolute value ranging from 7mm to 10mm, and an optical material of IRG206; and the fifteenth lens has a front and back curvature radius ranging from -140mm to -110mm and from -289mm to -259mm, an optical thickness absolute value ranging from 13mm to 16mm, and an optical material of ZNS-BROAD.

[0014] Therefore, the three-mode composite optical system can split light of laser, visible light and infrared light, and image through different optical systems, so as to meet the actual application requirements of multi-mode composite optical system imaging performance verification and system adjustment, and has good imaging effect, compact system structure and small volume.

[0015] The technical solutions of the present application are described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 FIG. 1 is a schematic structural diagram of a three-mode composite optical system according to the present application;

[0017] Figure 2 FIG. 4 is a schematic structural diagram of a laser system according to the present application;

[0018] Figure 3 FIG. 5 is a schematic structural diagram of a visible light system according to the present application;

[0019] Figure 4 FIG. 6 is a schematic structural diagram of a long-wave infrared system according to the present application;

[0020] Figure 5 FIG. 7 is an MTF curve diagram of the laser system according to the present application;

[0021] Figure 6Point spread function (PSF) plot for the laser system of the present application;

[0022] Figure 7 MTF plot for the visible light system of the present application;

[0023] Figure 8 Point spread function (PSF) plot for the visible light system of the present application;

[0024] Figure 9 MTF plot for the long wave infrared system of the present application;

[0025] Figure 10 Point spread function (PSF) plot for the long wave infrared system of the present application;

[0026] Reference numerals

[0027] 1, object plane; 2, primary mirror; 3, secondary mirror; 4, first beam splitter; 5, second beam splitter; 6, first lens group; 7, first filter; 8, first detector; 9, second lens group; 10, second filter; 11, second detector; 12, third lens group; 13, third filter; 14, third detector; 15, first lens; 16, second lens; 17, third lens; 18, fourth lens; 19, fifth lens; 20, sixth lens; 21, seventh lens; 22, eighth lens; 23, ninth lens; 24, tenth lens; 25, eleventh lens; 26, twelfth lens; 27, thirteenth lens; 28, fourteenth lens; 29, fifteenth lens. DETAILED DESCRIPTION

[0028] The following detailed description of embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the application claimed, but merely represents selected embodiments of the application. Based upon the embodiments of the present application, all other embodiments that are obtained by those of ordinary skill in the art without creative work are within the scope of the present application.

[0029] Referring to Figures 1-10 A three-mode composite optical system comprising an object plane 1, a primary mirror 2, a secondary mirror 3, a first beam splitter 4, a second beam splitter 5, a laser system, a visible light system, and a long wave infrared system;

[0030] The light emitted by the object plane 1 is reflected by the secondary mirror 3 and the primary mirror 2 to the first beam splitter 4, and is transmitted to the second beam splitter 5, and the light path is reflected by the second beam splitter 5 to form a laser system; the laser system comprises a first lens group 6, a first filter 7 and a first detector 8; the light reflected by the second beam splitter 5 is received by the first detector 8 through the first lens group 6 and the first filter 7; wherein the first lens group 6 comprises a first lens 15, a second lens 16 and a third lens 17 arranged away from the second beam splitter 5 in sequence. The front and back curvature radius ranges of the first lens 15 are 67mm-97mm and 10mm-40mm; the absolute value range of the optical thickness is 12mm-15mm; the optical material is H-LAK5A; the front and back curvature radius ranges of the second lens 16 are -35mm--5mm and -64mm--34mm; the absolute value range of the optical thickness is 3mm-6mm; the optical material is H-ZLAF76A; the front and back curvature radius ranges of the third lens 17 are -5mm-25mm and -3mm-27mm; the absolute value range of the optical thickness is 4mm-7mm; the optical material is H-ZLAF90.

[0031] The light emitted by the object plane 1 is reflected by the sub-mirror 3 and the main mirror 2 to the first beam splitter 4, and the reflected light path through the first beam splitter 4 forms a visible light system; the visible light system comprises a second lens group 9, a second filter 10 and a second detector 11; the light beam reflected by the first beam splitter 4 is received by the second detector 11 through the second lens group 9 and the second filter 10; wherein the second lens group 9 comprises a fourth lens 18, a fifth lens 19, a sixth lens 20, a seventh lens 21, an eighth lens 22 and a ninth lens 23 arranged away from the first beam splitter 4 in sequence. The fourth lens 18 has a front and back curvature radius range of -74mm~ -44mm and 69mm~99mm; an optical thickness absolute value range of 6mm~9mm; and an optical material of H-ZK50GT; the fifth lens 19 has a front and back curvature radius range of -32mm~ -2mm and -87mm~ -57mm; an optical thickness absolute value range of 3mm~6mm; and an optical material of H-ZLAF68B; the sixth lens 20 has a front and back curvature radius range of 1mm~31mm and -51mm~ -21mm; an optical thickness absolute value range of 2mm~5mm; and an optical material of H-ZF88GT; the seventh lens 21 has a front and back curvature radius range of 95mm~125mm and 3mm~33mm; an optical thickness absolute value range of 3mm~6mm; and an optical material of H-ZLAF68B; the eighth lens 22 has a front and back curvature radius range of -91mm~ -61mm and 44mm~74mm; an optical thickness absolute value range of 3mm~6mm; and an optical material of H-ZLAF50E; the ninth lens 23 has a front and back curvature radius range of -33mm~ -3mm and 44mm~74mm; an optical thickness absolute value range of 12mm~15mm; and an optical material of H-ZLAF68B.

[0032] The light emitted by the object plane 1 is reflected by the sub-mirror 3 and the main mirror 2 to the first beam splitter 4, and is transmitted by the first beam splitter 4 to the second beam splitter 5. The transmitted light path on the second beam splitter 5 forms a long-wave infrared system. The long-wave infrared system comprises a third lens group 12, a third filter 13 and a third detector 14. The light beam transmitted by the second beam splitter 5 is received by the third detector 14 through the third lens group 12 and the third filter 13. The third lens group 12 comprises a tenth lens 24, an eleventh lens 25, a twelfth lens 26, a thirteenth lens 27, a fourteenth lens 28 and a fifteenth lens 29 arranged away from the second beam splitter 5 in sequence. The tenth lens 24 has a front and back curvature radius range of 158mm-188mm and -559mm-529mm, an optical thickness absolute value range of 8mm-11mm, and an optical material of GERMANIUM. The eleventh lens 25 has a front and back curvature radius range of 17mm-47mm and 7mm-37mm, an optical thickness absolute value range of 2mm-5mm, and an optical material of GERMANIUM. The twelfth lens 26 has a front and back curvature radius range of 10mm-40mm and 22mm-52mm, an optical thickness absolute value range of 2mm-5mm, and an optical material of ZNSE. The thirteenth lens 27 has a front and back curvature radius range of -24mm-6mm and -33mm-3mm, an optical thickness absolute value range of 7mm-10mm, and an optical material of GERMANIUM. The fourteenth lens 28 has a front and back curvature radius range of 11mm-41mm and -110mm-80mm, an optical thickness absolute value range of 7mm-10mm, and an optical material of IRG206. The fifteenth lens 29 has a front and back curvature radius range of -140mm-110mm and -289mm-259mm, an optical thickness absolute value range of 13mm-16mm, and an optical material of ZNS-BROAD.

[0033] Embodiment

[0034] It should be noted that the negative thickness in the embodiment indicates the negative propagation thickness in the optical design along the light propagation direction, which conforms to the modeling habit of optical software.

[0035] In the embodiment, the first lens 15 has a front and back curvature radius of 82.414 mm and 25.065 mm, an optical thickness of -13.587 mm, and an optical material of H-LAK5A; the second lens 16 has a front and back curvature radius of -20.081 mm and -49.488 mm, an optical thickness of -4.524 mm, and an optical material of H-ZLAF76A; the third lens 17 has a front and back curvature radius of 9.910 mm and 12.384 mm, an optical thickness of -6.043 mm, and an optical material of H-ZLAF90; and the fourth lens 18 has a front and back curvature radius of -59.245 mm and 83.560 mm, an optical thickness of -6.628 mm, and an optical material of H-ZK50GT. Table 1 shows the specific parameters of the optical elements

[0036] Table 1

[0037]

[0038]

[0039] In the embodiment, the first lens 15 has a front and back curvature radius of 82.414 mm and 25.065 mm, an optical thickness of -13.587 mm, and an optical material of H-LAK5A; the second lens 16 has a front and back curvature radius of -20.081 mm and -49.488 mm, an optical thickness of -4.524 mm, and an optical material of H-ZLAF76A; the third lens 17 has a front and back curvature radius of 9.910 mm and 12.384 mm, an optical thickness of -6.043 mm, and an optical material of H-ZLAF90; and the fourth lens 18 has a front and back curvature radius of -59.245 mm and 83.560 mm, an optical thickness of -6.628 mm, and an optical material of H-ZK50GT. Table 1 shows the specific parameters of the optical elements

[0040] Table 2

[0041]

[0042]

[0043] In this embodiment, the tenth lens 24 has front and back radii of curvature of 172.849 mm and -544.359 mm; an optical thickness of 9.913 mm; and an optical material of GERMANIUM; the eleventh lens 25 has front and back radii of curvature of 31.793 mm and 21.822 mm; an optical thickness of 3.690 mm; and an optical material of GERMANIUM; the twelfth lens 26 has front and back radii of curvature of 24.898 mm and 37.129 mm; an optical thickness of 3.037 mm; and an optical material of ZNSE; the thirteenth lens 27 has front and back radii of curvature of -9.074 mm and -18.018 mm; an optical thickness of 8.292 mm; and an optical material of GERMANIUM; the fourteenth lens 28 has front and back radii of curvature of 26.032 mm and -94.834 mm; an optical thickness of 8.008 mm; and an optical material of IRG206; and the fifteenth lens 29 has front and back radii of curvature of -124.906 mm and -273.541 mm; an optical thickness of 14.408 mm; and an optical material of ZNS-BROAD. Table 3 shows the specific parameters of the optical elements.

[0044] Table 3

[0045]

[0046]

[0047] From Figure 5 it can be seen that the system has a very high MTF response at the center field of view (0.0000 degree), with the low frequency part close to the ideal value (MTF ≈ 1.0), indicating that the system has good contrast transfer capability for large-scale targets. As the field angle increases (such as 0.1500 degrees), the MTF response gradually decreases, mainly due to edge aberrations such as field curvature and astigmatism. There is a certain difference between the MTF curves in the sagittal (meridional) and tangential (tangential) directions, showing that the system has been optimized for astigmatism in the full field of view, but there is still a slight residual at large field angles. Overall, the optical system still has significant imaging capability at a spatial frequency of 39 cycles / mm at a wavelength of 532 nm, verifying its good performance in imaging resolution and contrast retention, and meeting the design requirements of high-performance imaging applications.

[0048] As Figure 6To further evaluate the imaging quality of the optical system at different fields of view, a spot diagram based on wavelength 532 nm is plotted. The spot distribution from 0.0000° to 0.1500° field of view is shown in the figure, and the figure is the image plane, with units of mm. The spot diagram of the central field of view (0.0000°) is approximately circular, and the spot is compact, indicating that the system has excellent imaging performance near the optical axis. As the field of view angle increases, the spot gradually deviates from the center and expands to a certain extent, reflecting the increase of aberration effects at the edge of the field of view, mainly including coma, astigmatism and field curvature, etc. Especially at 0.1500°, the spot appears obvious stretching, spreading and even double-peak phenomenon, which shows that the imaging quality of the system at the extreme field of view is significantly reduced, and the edge performance limit needs to be concerned in actual use. As can be seen from the RMS (root mean square radius) and GEO (geometric mean radius) values listed below the figure, the RMS of the central spot (point 1) is only 15.134 μm, while the edge (point 10) reaches 17.984 μm, and the geometric mean value even rises to 49.186 μm, which confirms the influence of edge aberration. In addition, the spot at each field of view includes multiple wavefront sample points, indicating that the simulation considers the beam distribution at the actual entrance pupil. Overall, the system has good focusing performance at the center and intermediate field of view, and the edge spot change reveals the boundary characteristics of the system imaging range.

[0049] Figure 7 The complex light modulation transfer function (MTF) curve of the optical system in the wavelength range of 550 nm to 750 nm is shown, which is used to evaluate the color difference control and overall imaging performance of the system under wide-band imaging conditions. The meridional and tangential direction MTF performance of multiple angles from the optical axis center (0.0000°) to the edge of the field of view (0.7500°) is included in the figure. In the entire spatial frequency range, the MTF curves of each field of view angle all show a stable and smooth downward trend, and the MTF of the central field of view still maintains a high value (close to 0.7) in the high frequency region, indicating that the system has good resolving power for high spatial frequency details. Although the edge field of view has a certain decline, it still maintains an MTF value of more than 0.4 below 54.6 cycles / mm, indicating that the system has excellent full-field imaging consistency. In addition, the MTF curves of different wavelengths have small differences, showing that the system effectively controls the on-axis and off-axis chromatic aberrations, and has good multi-wavelength imaging ability. This feature makes it particularly suitable for multi-band laser imaging, complex color illumination detection or wide-spectrum imaging systems.

[0050] Figure 8The point spread function (PSF) of the optical system is shown in the wavelength of 532 nm, which shows the imaging focusing ability and aberration performance in different field angles. The figure shows the light spot distribution of 10 typical angles from the object field of 0.0000° to ±0.1500°, and the image plane position is corrected by aberration, which represents the final imaging position of the system. At the center of the optical axis (0.0000°), the light spot presents an approximate circle and is highly concentrated, indicating that the system has excellent imaging sharpness and minimal wavefront distortion in the axial direction. As the field angle increases, the light spot gradually shows stretching, deformation or diffusion trend, especially at the ±0.1500° angle, the light spot shows typical coma and astigmatism characteristics, reflecting the cumulative effect of non-axial aberration. The RMS radius and the geometric mean radius (GEO Radius) in the table further quantify the changes in imaging quality. The center field point (point 1) RMS is 15.135 μm, and the edge field point (point 10) RMS is 17.984 μm, and the geometric radius also increases, indicating that the system still maintains acceptable imaging performance in the edge imaging area, with good full field consistency.

[0051] As Figure 9 shown, the complex light modulation transfer function (MTF) curve of the optical system in the wavelength range of 8.500 μm to 13.500 μm shows the imaging performance of the system in the mid-infrared band. The figure lists the meridional and tangential direction MTF performance of multiple field points from the center of the optical axis (0.0000°) to the maximum field angle (±1.3181°). Overall, the MTF curve of the system shows a smooth downward trend in each field of view, and maintains a high OTF modulus value (about 0.5-0.6) when the spatial frequency reaches 20 cycles / mm, indicating that it has good high-frequency detail resolution capability in mid-infrared imaging applications. The MTF is highest at the center of the field of view, and although it decreases slightly at the edge of the field of view, the curve convergence consistency is good, which reflects the full field imaging uniformity and chromatic aberration control ability of the system. Such performance is particularly critical for mid-infrared imaging systems, such as thermal imaging, infrared detection and remote sensing applications, which require higher resolution and wavelength adaptability. The system optimizes the wavelength coverage design, effectively controls the chromatic aberration and aberration, and ensures stable imaging quality under multi-wavelength conditions.

[0052] Figure 10The spot diagrams of the optical system at multiple field angles (from 0.0000° to ±1.3181° in the object space) at the wavelength of 13.5 μm are shown in the table. Each spot diagram shows the imaging spot of the corresponding field point, which can be used to intuitively evaluate the focusing ability and the level of aberration control of the system in the mid-infrared band. The spot at the central field (0.0000°) presents a regular and symmetrical diamond structure with a compact size, which indicates that the system has good focusing accuracy and minimum aberration in the axial direction. As the field angle increases, especially at ±1.3181°, the spot gradually presents an asymmetric expansion, edge stretching and complex structure, which reflects the appearance of typical edge aberrations such as coma and field curvature. The RMS radius listed in the table is only 12.367 μm at the central point, while it rises to 16.652 μm at the maximum field (point 10), and the geometric radius (GEO) also increases, which indicates that although the edge aberration has increased, the system as a whole still maintains a high level of imaging quality, and is particularly suitable for mid-infrared imaging applications such as infrared remote sensing, thermal imaging and large field detection.

[0053] Therefore, the present application adopts the above-mentioned three-mode composite optical system, which shares a secondary mirror and a primary mirror, and uses two beam splitters for light splitting, so that the system is suitable for laser, visible light and long-wave infrared light, reduces the system size while ensuring the optical imaging quality, reduces the cost, and has a wide range of applications.

[0054] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A triple modular compound optical system characterized by: The object plane, the primary mirror, the secondary mirror, the first beam splitter, the second beam splitter, a laser system, a visible light system and a long-wave infrared system are included. The light emitted by the object plane is reflected by the secondary mirror and the primary mirror to the first beam splitter, and is transmitted to the second beam splitter, and the reflected light path through the second beam splitter forms the laser system. The light emitted by the object plane is reflected by the secondary mirror and the primary mirror to the first beam splitter, and the reflected light path through the first beam splitter forms the visible light system. The light emitted by the object plane is reflected by the secondary mirror and the primary mirror to the first beam splitter, and is transmitted to the second beam splitter through the first beam splitter, and the transmitted light path through the second beam splitter forms the long-wave infrared system. The laser system includes a first lens group, and the first lens group includes a first lens, a second lens and a third lens arranged away from the second beam splitter in sequence. The first lens has a front and back curvature radius range of 67mm-97mm and 10mm-40mm, and an optical thickness absolute value range of 12mm-15mm; the second lens has a front and back curvature radius range of -35mm--5mm and -64mm--34mm, and an optical thickness absolute value range of 3mm-6mm; and the third lens has a front and back curvature radius range of -5mm-25mm and -3mm-27mm, and an optical thickness absolute value range of 4mm-7mm. The visible light system includes a second lens group, and the second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged away from the first beam splitter in sequence. The fourth lens has a front and back curvature radius range of -74mm--44mm and 69mm-99mm, and an optical thickness absolute value range of 6mm-9mm; the fifth lens has a front and back curvature radius range of -32mm--2mm and -87mm--57mm, and an optical thickness absolute value range of 3mm-6mm; the sixth lens has a front and back curvature radius range of 1mm-31mm and -51mm--21mm, and an optical thickness absolute value range of 2mm-5mm; the seventh lens has a front and back curvature radius range of 95mm-125mm and 3mm-33mm, and an optical thickness absolute value range of 3mm-6mm; the eighth lens has a front and back curvature radius range of -91mm--61mm and 44mm-74mm, and an optical thickness absolute value range of 3mm-6mm; and the ninth lens has a front and back curvature radius range of -33mm--3mm and 44mm-74mm, and an optical thickness absolute value range of 12mm-15mm. The long-wave infrared system includes a third lens group, and the third lens group includes a tenth lens, an eleventh lens, a twelfth lens, a thirteenth lens, a fourteenth lens and a fifteenth lens arranged away from the second beam splitter in sequence. The tenth lens has a front and back curvature radius range of 158mm-188mm and -559mm-529mm, an optical thickness absolute value range of 8mm-11mm, the eleventh lens has a front and back curvature radius range of 17mm-47mm and 7mm-37mm, an optical thickness absolute value range of 2mm-5mm, the twelfth lens has a front and back curvature radius range of 10mm-40mm and 22mm-52mm, an optical thickness absolute value range of 2mm-5mm, the thirteenth lens has a front and back curvature radius range of -24mm-6mm and -33mm-3mm, an optical thickness absolute value range of 7mm-10mm, the fourteenth lens has a front and back curvature radius range of 11mm-41mm and -110mm-80mm, an optical thickness absolute value range of 7mm-10mm, and the fifteenth lens has a front and back curvature radius range of -140mm-110mm and -289mm-259mm, an optical thickness absolute value range of 13mm-16mm.

2. A three-mode compound optical system according to claim 1, characterized in that: The laser system further comprises a first filter and a first detector; the light beam reflected on the second beam splitter passes through the first lens group and the first filter and is received by the first detector.

3. A three-mode compound optical system according to claim 2, characterized in that: The visible light system further comprises a second filter and a second detector; the light beam reflected by the first beam splitter passes through the second lens group and the second filter and is received by the second detector.

4. A three-mode compound optical system according to claim 3, wherein: The long-wave infrared system further comprises a third filter and a third detector; the light beam transmitted on the second beam splitter passes through the third lens group and the third filter and is received by the third detector.

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