Low-cost small-scale space debris wide-area detection optical system

Abstract

The application relates to a low-cost small-scale space debris wide-area detection optical system, which is used for solving the problems that the current optical system has a large field of view and a small entrance pupil diameter, the system detection capability is limited, and the number of system elements and aspheric surfaces is too large, so that the system cost is high. The application comprises a first positive lens, a second negative lens, a second positive lens, a third positive lens, a second negative lens, a third negative lens and a surface arranged in sequence on the same optical axis along the light propagation direction; the first positive lens is mainly used for correcting the positive spherical aberration, negative coma and positive astigmatism of the system; the first negative lens is mainly used for correcting the positive spherical aberration, positive coma and negative distortion of the system; the second positive lens is mainly used for correcting the chromatic aberration of the system; the third positive lens is mainly used for correcting the positive axial chromatic aberration of the system; the second negative lens is mainly used for correcting the positive spherical aberration and positive distortion of the system; and the third negative lens is mainly used for correcting the positive curvature of field and positive distortion of the system.

Description

Technical Field

[0001] This invention relates to a space optical system, specifically a low-cost, small-scale, wide-area detection optical system for space debris. Background Technology

[0002] In the study of space debris, the most worrying phenomenon is the "Kessler Syndrome," which posits that collisions between pieces of space debris inevitably generate more and smaller pieces, similar to an avalanche, leading to a dramatic increase in the amount of space debris. Donald Kessler pointed out that if a series of collisions reaches a trigger point, it could create a chain reaction, continuously exacerbating the space debris problem. Space debris traveling at speeds exceeding 28,000 km / h can pierce an astronaut's spacesuit or cause severe cracks in a space shuttle window. Space debris with a diameter of 10 cm can destroy a remote sensing or communication satellite, or other expensive space assets, while the protective shields on satellite surfaces can only protect them from impacts by debris smaller than 1 cm in diameter.

[0003] Currently, the biggest threat we face is high-speed space debris, which may destroy communication satellites, critical spacecraft, and even endanger the lives of astronauts. At the same time, falling debris may also cause other property damage, or even casualties. Space debris may even directly damage the functional components of spacecraft, leading to spacecraft system malfunctions or failures.

[0004] Therefore, by detecting small-scale space debris, we can accurately grasp the orbital information of spacecraft in orbit and space debris, thus avoiding risks, preventing collision events, and realizing space debris monitoring and early warning.

[0005] To detect smaller space debris, it is necessary to increase the aperture and spectral range of the optical system. However, increasing the aperture and spectral range of the optical system directly affects spherical aberration, coma, distortion, field curvature, and transverse chromatic aberration, greatly increasing the design complexity of the system. Currently published optical systems either have a large field of view but a small entrance pupil diameter, resulting in limited system detection capabilities; or an excessive number of optical system elements and aspherical surfaces, leading to high system costs and failing to meet the requirements for wide-area space debris detection. Summary of the Invention

[0006] This invention provides a low-cost, small-scale space debris wide-area detection optical system with excellent performance indicators, an entrance pupil diameter exceeding 100mm, and a spectral range of 450nm-850nm. It can meet the requirements for wide-area space debris detection within a 22°*22° field of view. This invention addresses the problems of current optical systems, such as large field of view but small entrance pupil diameter, resulting in limited system detection capability, and the high cost due to the excessive number of components and aspherical surfaces in existing optical systems.

[0007] To achieve the above objective, the technical solution of the present invention is as follows:

[0008] A low-cost wide-field detection optical system for small-scale space debris, characterized in that it comprises a first positive lens, a first negative lens, a second positive lens, a third positive lens, a second negative lens, a third negative lens and an image plane which are sequentially arranged on the same optical axis along the light propagation direction;

[0009] The first positive lens is configured to correct positive spherical aberration, negative coma and positive astigmatism of the system; the front surface of the first positive lens 1 is a high-order aspheric surface, which is configured to correct the spherical aberration of the system;

[0010] The first negative lens is configured to correct positive spherical aberration, positive coma and negative distortion of the system;

[0011] The second positive lens is configured to correct chromatic aberration of the system;

[0012] The third positive lens is configured to correct positive axial chromatic aberration of the system;

[0013] The second negative lens is configured to correct positive spherical aberration and positive distortion of the system;

[0014] The third negative lens is configured to correct positive field curvature and positive distortion of the system.

[0015] Further, the relationship between the focal length f1 of the first positive lens and the system focal length f is 1.5f < f1 < 2.1f, the refractive index is 1.42 to 1.73, and the Abbe number is 78 to 95;

[0016] The relationship between the focal length f2 of the first negative lens and the system focal length f is: -1.25f < f2 < -1.15f, the refractive index is 1.4 to 1.75, and the Abbe number is 41 to 45;

[0017] The relationship between the focal length f3 of the second positive lens and the system focal length f is: 0.75f < f3 < 0.82f, the refractive index is 1.4 to 1.75, and the Abbe number is 69 to 92;

[0018] The relationship between the focal length f4 of the third positive lens and the system focal length f is: 1.25f < f4 < 1.42f, the refractive index is 1.39 to 1.69, and the Abbe number is 77 to 88;

[0019] The relationship between the focal length f5 of the second negative lens and the system focal length f is: -2.3f < f5 < -2.1f, the refractive index is 1.43 to 1.7, and the Abbe number is 35 to 41;

[0020] The relationship between the focal length f6 of the third negative lens and the system focal length f is: -0.8f < f6 < -0.65f, the refractive index is 1.49 to 1.75, and the Abbe number is 60 to 69.

[0021] Further, the radius of curvature R1 of the front surface of the first positive lens satisfies 0.53f<R1<0.89f, and the rear surface is a plane;

[0022] the radius of curvature R3 of the front surface of the first negative lens satisfies 1.21f<R3<1.42f, and the radius of curvature R4 of the rear surface thereof satisfies 0.36f<R4<0.5f;

[0023] the radius of curvature R5 of the front surface of the second positive lens satisfies 0.51f<R5<0.55f, and the radius of curvature R6 of the rear surface thereof satisfies -0.9f<R6<-0.75f;

[0024] the radius of curvature R7 of the front surface of the third positive lens satisfies -3.1f<R7<-2.8f, and the radius of curvature R8 of the rear surface thereof satisfies -0.54f<R8<-0.35f;

[0025] the radius of curvature R9 of the front surface of the second negative lens satisfies -0.4f<R9<-0.35f, and the radius of curvature R10 of the rear surface thereof satisfies -0.6f<R10<-0.5f;

[0026] the radius of curvature R11 of the front surface of the third negative lens satisfies -0.45f<R11<-0.35f, and the radius of curvature R12 of the rear surface thereof satisfies 2.96f<R12<3.25f.

[0027] Further, the thickness t1 of the first positive lens satisfies 0.09f<t1<0.1f;

[0028] the thickness t2 of the first negative lens satisfies 0.079f<t2<0.082f;

[0029] the thickness t3 of the second positive lens satisfies 0.11f<t3<0.125f;

[0030] the thickness t4 of the third positive lens satisfies 0.09f<t4<0.11f;

[0031] the thickness t5 of the second negative lens satisfies 0.05f<t5<0.07f;

[0032] the thickness t6 of the third negative lens satisfies 0.025f<t6<0.035f.

[0033] Further, the distance d1 from the front surface of the first negative lens to the rear surface of the first positive lens satisfies 0.14f<d1<0.16f;

[0034] the distance d2 between the front surface of the second positive lens and the rear surface of the first negative lens satisfies 0.18f<d2<0.2f;

[0035] The distance d3 from the front surface of the third positive lens to the rear surface of the second positive lens is 0.21f. <d3<0.25f;

[0036] The distance d4 from the front surface of the second negative lens to the rear surface of the third positive lens is 0.03f. <d4<0.04f

[0037] The distance d5 from the front surface of the third negative lens to the rear surface of the second negative lens is 0.35f. <d5<0.42f;

[0038] The distance d6 from the rear surface of the third negative lens to the image plane is 0.02f. <d6<0.04f。

[0039] Furthermore, the front surface of the first positive lens is a high-order aspherical surface, mainly used to correct the spherical aberration of the system, and its expression is as follows:

[0040] ;

[0041] Where K = -4 to -0.5, A = -9.4e-009 to -7.4e-011, B = -1.3e-010 to -2.5e-14, C = -3.3e-015 to -2.7e-19, z is the aspherical sagitta for different apertures, c is the aspherical curvature, r is the aspherical aperture, K is the quadratic surface coefficient, and A, B, and C are the coefficients of higher-order terms of higher-order aspherical surfaces.

[0042] Furthermore, the focal length f is 250mm;

[0043] The first positive lens has a refractive index of 1.43, an Abbe number of 90, a focal length f1 of 441.33 mm, a radius of curvature R1 of the front surface of 191.34 mm, a flat rear surface, and a thickness t1 of 24.94 mm.

[0044] The first negative lens has a refractive index of 1.6, an Abbe number of 45, a focal length f2 of -296.18 mm, a radius of curvature R3 of the front surface of 328.81 mm, a radius of curvature R4 of the rear surface of 117.02 mm, and a thickness t2 of 20 mm; the distance d1 from the front surface of the first negative lens to the rear surface of the first positive lens is 39.17 mm.

[0045] The second positive lens has a refractive index of 1.45, an Abbe number of 92, a focal length of f3 of 195.80 mm, a radius of curvature R5 of the front surface of 136.77 mm, a radius of curvature R6 of the rear surface of -208.95 mm, a thickness of t3 of 30 mm, and a distance d2 from the front surface of the second positive lens to the rear surface of the first negative lens of 48.45 mm.

[0046] The third positive lens has a refractive index of 1.44, an Abbe number of 88, a focal length of f4 of 329.34 mm, a front surface radius of curvature R7 of -741.85 mm, a rear surface radius of curvature R8 of -122.11 mm, a thickness of t4 of 25 mm, and a distance d3 from the front surface of the third positive lens to the rear surface of the second positive lens of 58 mm.

[0047] The second negative lens has a refractive index of 1.69, an Abbe number of 40, a focal length of f5 of -549.51 mm, a radius of curvature of R9 on the front surface of -96.81 mm, a radius of curvature of R10 on the rear surface of -140.7 mm, a thickness of t5 of 15 mm, and a distance d4 from the front surface of the second negative lens to the rear surface of the third positive lens of 8.35 mm.

[0048] The third negative lens has a refractive index of 1.5, an Abbe number of 61, and a focal length of f6 of -175.68 mm. The radius of curvature R11 of the front surface is -103.39 mm, the radius of curvature R12 of the rear surface is 757.56 mm, and the thickness t6 is 7.5 mm. The distance d5 from the front surface of the third negative lens to the rear surface of the second negative lens is 95.27 mm, and the distance d6 from the rear surface of the third negative lens to the image plane is 7 mm.

[0049] Furthermore, the entrance pupil diameter is 100mm, the designed wavelength is 450nm~850nm; the field of view is 22°, and the focal length f is 200mm.

[0050] The first positive lens has a refractive index of 1.65, an Abbe number of 82, a focal length of f1 of 353.06 mm, a radius of curvature R1 of the front surface of 153.71 mm, a flat rear surface, and a thickness of t1 of 19.63 mm.

[0051] The first negative lens has a refractive index of 1.43, an Abbe number of 45, a focal length of f2 of -236.96 mm, a radius of curvature R3 of the front surface of 262.59 mm, a radius of curvature R4 of the rear surface of 93.69 mm, a thickness of t2 of 15.99 mm, and a distance d1 from the front surface of the first negative lens to the rear surface of the first positive lens of 31.34 mm.

[0052] The second positive lens has a refractive index of 1.44, an Abbe number of 81, a focal length of f3 of 156.64 mm, a radius of curvature R5 of the front surface of 109.82 mm, a radius of curvature R6 of the rear surface of -166.05 mm, a thickness of t3 of 24 mm, and a distance d2 from the front surface of the second positive lens to the rear surface of the first negative lens of 38.58 mm.

[0053] The third positive lens has a refractive index of 1.4, an Abbe number of 80, a focal length of f4 of 263.47 mm, a radius of curvature R7 of the front surface of -573.37 mm, a radius of curvature R8 of the rear surface of -97.45 mm, a thickness of t4 of 20 mm, and a distance d3 from the front surface of the third positive lens to the rear surface of the second positive lens of 46.7 mm.

[0054] The second negative lens has a refractive index of 1.6, an Abbe number of 37, a focal length of f5 of -439.6 mm, a radius of curvature of R9 on the front surface of -77.52 mm, a radius of curvature of R10 on the rear surface of -112.38 mm, a thickness of t5 of 12 mm, and a distance d4 from the front surface of the second negative lens to the rear surface of the third positive lens of 6.6 mm.

[0055] The third negative lens has a refractive index of 1.55, an Abbe number of 65, and a focal length of f6 of -140.54 mm. The radius of curvature R11 of the front surface is -82.46 mm, the radius of curvature R12 of the rear surface is 618.5 mm, and the thickness t6 is 6 mm. The distance d5 from the front surface of the third negative lens to the rear surface of the second negative lens is 76.54 mm, and the distance d6 from the rear surface of the third negative lens to the image plane is 6.6 mm.

[0056] Furthermore, the front surface of the first positive lens is a high-order aspherical surface, as expressed below:

[0057] ;

[0058] Where K = -1.7003, A = -8.4025e-009, B = -1.3796e-012, C = -3.3116e-017, z is the aspherical sag for different apertures, c is the aspherical curvature, r is the aspherical aperture, K is the quadratic surface coefficient, and A, B, and C are the coefficients of higher-order terms of higher-order aspherical surfaces.

[0059] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0060] 1. In this invention, multiple lenses are used in combination, and the front surface of the first positive lens is aspherical, which achieves an entrance pupil diameter of more than 100mm, and 80% of the circle of confusion diameter is controlled within the range of 12μm-18μm within a 22° field of view, resulting in a uniform dispersion pattern across the entire field of view of the optical system.

[0061] 2. In this invention, the front surface of the first positive lens is a high-order aspherical surface, and the rear surface is a plane. The front surface can be detected through the rear surface, which reduces the difficulty of processing and detection. At the same time, the optical system has a small number of aspherical surfaces and components, resulting in lower cost. Attached Figure Description

[0062] Figure 1is a schematic structural diagram of the large-scale low-distortion space debris detection optical system of the present invention.

[0063] Figure 2 is an energy concentration curve detected by the large-scale low-distortion space debris detection optical system in the first embodiment of the present invention

[0064] Figure 3 is the diameter of the 80% encircled energy circle detected by the large-scale low-distortion space debris detection optical system in the first embodiment of the present invention.

[0065] Figure 4 is an aberration distortion curve detected by the large-scale low-distortion space debris detection optical system in the first embodiment of the present invention.

[0066] Figure 5 is an energy concentration curve detected by the large-scale low-distortion space debris detection optical system in the second embodiment of the present invention

[0067] Figure 6 is the diameter of the 80% encircled energy circle detected by the large-scale low-distortion space debris detection optical system in the second embodiment of the present invention.

[0068] wherein, 1 is the first positive lens, 2 is the first negative lens, 3 is the second positive lens, 4 is the third positive lens, 5 is the second negative lens, 6 is the third negative lens, 7 is the image plane. DETAILED DESCRIPTION

[0069] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0070] A low-cost wide-area detection optical system for small-scale space debris, as shown in Figure 1 , comprises a first positive lens 1, a first negative lens 2, a second positive lens 3, a third positive lens 4, a second negative lens 5, a third negative lens 6 and an image plane 7 which are sequentially arranged on the same optical axis along the light propagation direction, wherein the front surface of the first positive lens 1 is a high-order aspheric surface.

[0071] The first positive lens 1 is mainly used to correct positive spherical aberration, negative coma and positive astigmatism of the system, the refractive index thereof is 1.42-1.73, the Abbe number is 78-95, the relationship between the focal length f1 of the first positive lens and the focal length f of the system is 1.5f<f1<2.1f, the curvature radii R1 and R2 of the front and back surfaces of the first positive lens are respectively 0.53f<R1<0.89f, R2 is a plane, and the thickness t1 of the first positive lens is 0.09f<t1<0.1f; wherein the front surface of the first positive lens 1 is a high-order aspheric surface, which is mainly used to correct spherical aberration of the system, and the expression is as follows:

[0072] ;

[0073] wherein K=-4~-0.5, A=-9.4e-009~-7.4e-011, B=-1.3e-010~-2.5e-014, C=-3.3e-015~-2.7e-19, z is the aspheric sag at different calibers, c is the aspheric curvature, r is the aspheric caliber, K is the quadric surface coefficient, and A, B and C are coefficients of high-order terms of the high-order aspheric surface.

[0074] The first negative lens 2 is mainly used for correcting positive spherical aberration, positive coma and negative distortion of the system, has a refractive index of 1.4 to 1.75, an Abbe number of 41 to 45, and a focal length f2 satisfying: -1.25f<f2<-1.15f. The curvature radii R3 and R4 of the front and rear surfaces respectively satisfy: 1.21f<R3<1.42f and 0.36f<R4<0.5f, the thickness t2 satisfies 0.079f<t2<0.082f; the distance d1 from the front surface of the first negative lens 2 to the rear surface of the first positive lens 1 satisfies 0.14f<d1<0.16f.

[0075] The second positive lens 3 is mainly used for correcting chromatic aberration of the system, has a refractive index of 1.4 to 1.75, an Abbe number of 69 to 92, and a focal length f3 satisfying: 0.75f<f3<0.82f. The curvature radii R5 and R6 of the front and rear surfaces respectively satisfy: 0.51f<R5<0.55f and -0.9f<R6<-0.75f, the thickness t3 satisfies 0.11f<t3<0.125f; the distance d2 from the front surface of the second positive lens 3 to the rear surface of the first negative lens 2 satisfies 0.18f<d2<0.2f.

[0076] The third positive lens 4 is mainly used for correcting positive axial chromatic aberration of the system, has a refractive index of 1.39 to 1.69, an Abbe number of 77 to 88, and a focal length f4 satisfying: 1.25f<f4<1.42f. The curvature radii R7 and R8 of the front and rear surfaces respectively satisfy: -3.1f<R7<-2.8f and -0.54f<R8<-0.35f, the thickness t4 satisfies 0.09f<t4<0.11f; the distance d3 from the front surface of the third positive lens 4 to the rear surface of the second positive lens 3 satisfies 0.21f<d3<0.25f.

[0077] The second negative lens 5 is mainly used for correcting positive spherical aberration and positive distortion of the system, has a material refractive index of 1.43 to 1.7, an Abbe number of 35 to 41, and a focal length f5 satisfying: -2.3f<f5<-2.1f. The curvature radii R9 and R10 of the front and rear surfaces respectively satisfy: -0.4f<R9<-0.35f and -0.6f<R10<-0.5f, the thickness t5 satisfies 0.05f<t5<0.07f; the distance d4 from the front surface of the second negative lens 5 to the rear surface of the third positive lens 4 satisfies 0.03f<d4<0.04f.

[0078] The third negative lens 6 is mainly used to correct the positive field curvature and positive distortion of the system, its refractive index is 1.49 to 1.75, the Abbe number is 60 to 69, and the focal length f6 satisfies: -0.8f<f6<-0.65f. The curvature radii R11 and R12 of the front and rear surfaces satisfy: -0.45f<R11<-0.35f and 2.96f<R12<3.25f respectively, and the thickness t6 satisfies 0.025f<t6<0.035f; the distance d5 from the front surface of the third negative lens 6 to the rear surface of the second negative lens 5 satisfies 0.35f<d5<0.42f; the distance d6 from the rear surface of the third negative lens 6 to the image plane 7 satisfies 0.02f<d6<0.04f.

[0079] Embodiment 1

[0080] The entrance pupil diameter is 125mm, the design wavelength is 450nm to 850nm, the field of view angle is 22°, the focal length f is 250mm, so that 80% of the energy is concentrated in a circle with a diameter of 18μm in terms of energy concentration, and the distortion is less than 1%.

[0081] The first positive lens 1 has a refractive index of 1.43, an Abbe number of 90, a focal length f1 of 441.33mm, a curvature radius R1 of the front surface of 191.34mm, a planar rear surface, and a thickness t1 of 24.94mm; wherein the front surface of the first positive lens is a high-order aspheric surface, which is mainly used for correcting the spherical aberration of the system, and the expression is as follows:

[0082] ;

[0083] wherein K=-1.7003, A=-9.4025e-009, B=-1.3796e-012, C=-3.3116e-017, z is the sagittal height of the aspheric surface under different calibers, c is the curvature of the aspheric surface, r is the caliber of the aspheric surface, K is the quadric surface coefficient, and A, B and C are coefficients of high-order terms of the high-order aspheric surface.

[0084] The first negative lens 2 has a refractive index of 1.6 and an Abbe number of 45, its focal length f2 is -296.18mm, the curvature radius R3 of the front surface is 328.81mm, the curvature radius R4 of the rear surface is 117.02mm, the thickness t2 is 20mm; the distance d1 from the front surface of the first negative lens 2 to the rear surface of the first positive lens 1 is 39.17mm.

[0085] The second positive lens 3 has a refractive index of 1.45, an Abbe number of 92, a focal length f3 of 195.80mm, a curvature radius R5 of the front surface of 136.77mm, a curvature radius R6 of the rear surface of -208.95mm, a thickness t3 of 30mm; the distance d2 from the front surface of the second positive lens 3 to the rear surface of the first negative lens 2 is 48.45mm.

[0086] The third positive lens 4 has a refractive index of 1.44, an Abbe number of 88, a focal length of f4 of 329.34 mm, a front surface radius of curvature R7 of -741.85 mm, a rear surface radius of curvature R8 of -122.11 mm, a thickness of t4 of 25 mm, and a distance d3 from the front surface of the third positive lens 4 to the rear surface of the second positive lens 3 of 58 mm.

[0087] The second negative lens 5 has a refractive index of 1.69, an Abbe number of 40, a focal length of f5 of -549.51 mm, a front surface radius of curvature R9 of -96.81 mm, a rear surface radius of curvature R10 of -140.7 mm, a thickness of t5 of 15 mm, and a distance d4 from the front surface of the second negative lens 5 to the rear surface of the third positive lens 4 of 8.35 mm.

[0088] The third negative lens 6 has a refractive index of 1.5, an Abbe number of 61, and a focal length of f6 of -175.68 mm. The radius of curvature R11 of its front surface is -103.39 mm, the radius of curvature R12 of its rear surface is 757.56 mm, and its thickness t6 is 7.5 mm. The distance d5 from the front surface of the third negative lens 6 to the rear surface of the second negative lens 5 is 95.27 mm, and the distance d6 from the rear surface of the third negative lens 6 to the image plane 7 is 7 mm.

[0089] like Figure 2 The energy concentration curves of the optical system provided in the above embodiments shown are at 0°, 3°, 7°, and 11°, as follows: Figure 3 As shown, 80% of the energy circle diameters within the entire field of view are less than 18 μm, and the energy circle diameter range is controlled within 13.85 μm-17.43 μm.

[0090] like Figure 4 The optical system distortion curves provided in the above embodiments show that the distortion is less than 0.1% across the entire field of view.

[0091] Example 2

[0092] If the system aperture, focal length, or field of view is reduced, the system's blur spot will also decrease.

[0093] The entrance pupil diameter is 100mm, the designed wavelength is 450nm~850nm; the field of view is 22° and is a circular field of view, the focal length f is 200mm, which makes 80% of the energy concentrated in a circle with a diameter of 14μm, and the distortion is less than 1%.

[0094] The first positive lens 1 has a refractive index of 1.65, an Abbe number of 82, a focal length f1 of 353.06 mm, a front surface radius of curvature R1 of 153.71 mm, a rear surface that is flat, and a thickness t1 of 19.63 mm. The front surface of the first positive lens is a high-order aspherical surface, primarily used to correct spherical aberration in the system, and its expression is as follows:

[0095] ;

[0096] Where K = -1.7003, A = -8.4025e-009, B = -1.3796e-012, C = -3.3116e-017, z is the aspherical sag for different apertures, c is the aspherical curvature, r is the aspherical aperture, K is the quadratic surface coefficient, and A, B, and C are the coefficients of higher-order terms of higher-order aspherical surfaces.

[0097] The first negative lens 2 has a refractive index of 1.43, an Abbe number of 45, a focal length f2 of -236.96 mm, a front surface radius of curvature R3 of 262.59 mm, a rear surface radius of curvature R4 of 93.69 mm, and a thickness t2 of 15.99 mm. The distance d1 from the front surface of the first negative lens 2 to the rear surface of the first positive lens 1 is 31.34 mm.

[0098] The second positive lens 3 has a refractive index of 1.44, an Abbe number of 81, a focal length of f3 of 156.64 mm, a front surface radius of curvature R5 of 109.82 mm, a rear surface radius of curvature R6 of -166.05 mm, and a thickness of t3 of 24 mm. The distance d2 from the front surface of the second positive lens 3 to the rear surface of the first negative lens 2 is 38.58 mm.

[0099] The third positive lens 4 has a refractive index of 1.4, an Abbe number of 80, a focal length of f4 of 263.47 mm, a front surface radius of curvature R7 of -573.37 mm, a rear surface radius of curvature R8 of -97.45 mm, a thickness of t4 of 20 mm, and a distance d3 from the front surface of the third positive lens 4 to the rear surface of the second positive lens 3 of 46.7 mm.

[0100] The material of the second negative lens 5 has a refractive index of 1.6, an Abbe number of 37, a focal length of f5 of -439.6 mm, a radius of curvature of R9 on the front surface of -77.52 mm, a radius of curvature of R10 on the rear surface of -112.38 mm, a thickness of t5 of 12 mm, and a distance d4 from the front surface of the second negative lens 5 to the rear surface of the third positive lens 4 of 6.6 mm.

[0101] The third negative lens 6 has a refractive index of 1.55, an Abbe number of 65, and a focal length of f6 of -140.54 mm. The radius of curvature R11 of its front surface is -82.46 mm, the radius of curvature R12 of its rear surface is 618.5 mm, and its thickness t6 is 6 mm. The distance d5 from the front surface of the third negative lens 6 to the rear surface of the second negative lens 5 is 76.54 mm, and the distance d6 from the rear surface of the third negative lens 6 to the image plane 7 is 6.6 mm.

[0102] like Figure 5The energy concentration curves of the optical system provided in the above embodiments shown are at 0°, 3°, 7°, and 11°, as follows: Figure 6 As shown, 80% of the energy circle diameters within the entire field of view are less than 14 μm, and the energy circle diameter range is controlled within 11.08 μm-13.95 μm.

Claims

1. A low-cost, small-scale, wide-area optical system for detecting space debris, characterized in that: It comprises a first positive lens (1), a first negative lens (2), a second positive lens (3), a third positive lens (4), a second negative lens (5), a third negative lens (6) and an image plane (7), which are sequentially arranged along the light propagation direction on the same optical axis; The first positive lens (1) is used to correct positive spherical aberration, negative coma and positive astigmatism of the system; the front surface of the first positive lens (1) is a high-order aspheric surface for correcting system spherical aberration; The first negative lens (2) is used to correct positive spherical aberration, positive coma and negative distortion of the system; The second positive lens (3) is used to correct chromatic aberration of the system; The third positive lens (4) is used to correct positive axial chromatic aberration of the system; The second negative lens (5) is used to correct positive spherical aberration and positive distortion of the system; The third negative lens (6) is used to correct positive field curvature and positive distortion of the system; The relationship between the focal length f1 of the first positive lens (1) and the system focal length f is 1.5f<f1<2.1f, the refractive index is 1.42 to 1.73, and the Abbe number is 78 to 95; The relationship between the focal length f2 of the first negative lens (2) and the system focal length f is: -1.25f<f2<-1.15f, the refractive index is 1.4 to 1.75, and the Abbe number is 41 to 45; The relationship between the focal length f3 of the second positive lens (3) and the system focal length f is: 0.75f<f3<0.82f, the refractive index is 1.4 to 1.75, and the Abbe number is 69 to 92; The relationship between the focal length f4 of the third positive lens (4) and the system focal length f is: 1.25f<f4<1.42f, the refractive index is 1.39 to 1.69, and the Abbe number is 77 to 88; The relationship between the focal length f5 of the second negative lens (5) and the system focal length f is: -2.3f<f5<-2.1f, the refractive index is 1.43 to 1.7, and the Abbe number is 35 to 41; The relationship between the focal length f6 of the third negative lens (6) and the system focal length f is: -0.8f<f6<-0.65f, the refractive index is 1.49 to 1.75, and the Abbe number is 60 to 69.

2. The low-cost wide-area detection optical system for small-scale space debris according to claim 1, characterized in that: The curvature radius R1 of the front surface of the first positive lens (1) satisfies 0.53f<R1<0.89f, and the rear surface is a plane; The curvature radius R3 of the front surface of the first negative lens (2) satisfies 1.21f<R3<1.42f, and the curvature radius R4 of the rear surface satisfies 0.36f<R4<0.5f; The curvature radius R5 of the front surface of the second positive lens (3) satisfies 0.51f<R5<0.55f, and the curvature radius R6 of the rear surface satisfies -0.9f<R6<-0.75f; The curvature radius R7 of the front surface of the third positive lens (4) satisfies -3.1f<R7<-2.8f, and the curvature radius R8 of the rear surface satisfies -0.54f<R8<-0.35f; The curvature radius R9 of the front surface of the second negative lens (5) satisfies -0.4f<R9<-0.35f, and the curvature radius R10 of the rear surface satisfies -0.6f<R10<-0.5f; The curvature radius R11 of the front surface of the third negative lens (6) satisfies -0.45f < R11 < -0.35f, and the curvature radius R12 of the rear surface satisfies 2.96f < R12 < 3.25f.

3. A low-cost wide-area detection optical system for small-scale space debris according to claim 2, characterized in that: The thickness t1 of said first positive lens (1) satisfies 0.09f < t1 < 0.1f; The thickness t2 of said first negative lens (2) satisfies 0.079f < t2 < 0.082f; The thickness t3 of said second positive lens (3) satisfies 0.11f < t3 < 0.125f; The thickness t4 of said third positive lens (4) satisfies 0.09f < t4 < 0.11f; The thickness t5 of said second negative lens (5) satisfies 0.05f < t5 < 0.07f; The thickness t6 of said third negative lens (6) satisfies 0.025f < t6 < 0.035f.

4. A low-cost wide-area detection optical system for small-scale space debris according to claim 3, characterized in that: The distance d1 between the front surface of the first negative lens (2) and the rear surface of the first positive lens (1) satisfies 0.14f < d1 < 0.16f; The distance d2 between the front surface of the second positive lens (3) and the rear surface of the first negative lens (2) satisfies 0.18f < d2 < 0.2f; The distance d3 between the front surface of the third positive lens (4) and the rear surface of the second positive lens (3) satisfies 0.21f < d3 < 0.25f; The distance d4 between the front surface of the second negative lens (5) and the rear surface of the third positive lens (4) satisfies 0.03f < d4 < 0.04f; The distance d5 between the front surface of the third negative lens (6) and the rear surface of the second negative lens (5) satisfies 0.35f < d5 < 0.42f; The distance d6 between the rear surface of the third negative lens (6) and the image surface (7) satisfies 0.02f < d6 < 0.04f.

5. A low-cost wide-area detection optical system for small-scale space debris according to claim 4, characterized in that: The expression of the front surface of said first positive lens (1) is as follows: ； Wherein K = -4 ~ -0.5, A = -9.4e-009 ~ -7.4e-011, B = -1.3e-010 ~ -2.5e-014, C = -3.3e-015 ~ -2.7e-019, z is the aspheric sag at different apertures, c is the curvature of the aspheric surface, r is the aperture of the aspheric surface, K is the conic coefficient, and A, B and C are coefficients of high-order terms of the high-order aspheric surface.

6. A low-cost wide-area detection optical system for small-scale space debris according to claim 5, characterized in that: The focal length f of said system is 250 mm; Said first positive lens (1) has a refractive index of 1.43, an Abbe number of 90, a focal length f1 of 441.33 mm, a curvature radius R1 of the front surface of 191.34 mm, a planar rear surface, and a thickness t1 of 24.94 mm; The first negative lens (2) has a refractive index of 1.6, an Abbe number of 45, a focal length of f2 of -296.18 mm, a radius of curvature R3 of the front surface of 328.81 mm, a radius of curvature R4 of the rear surface of 117.02 mm, and a thickness of t2 of 20 mm; the distance d1 from the front surface of the first negative lens (2) to the rear surface of the first positive lens (1) is 39.17 mm; The second positive lens (3) has a refractive index of 1.45, an Abbe number of 92, a focal length of f3 of 195.80 mm, a radius of curvature R5 of the front surface of 136.77 mm, a radius of curvature R6 of the rear surface of -208.95 mm, a thickness of t3 of 30 mm, and a distance d2 between the front surface of the second positive lens (3) and the rear surface of the first negative lens (2) of 48.45 mm. The third positive lens (4) has a refractive index of 1.44, an Abbe number of 88, a focal length of f4 of 329.34 mm, a radius of curvature R7 of the front surface of -741.85 mm, a radius of curvature R8 of the rear surface of -122.11 mm, a thickness of t4 of 25 mm, and a distance d3 from the front surface of the third positive lens (4) to the rear surface of the second positive lens (3) of 58 mm. The second negative lens (5) has a refractive index of 1.69, an Abbe number of 40, a focal length of f5 of -549.51 mm, a radius of curvature of R9 on the front surface of -96.81 mm, a radius of curvature of R10 on the rear surface of -140.7 mm, a thickness of t5 of 15 mm, and a distance d4 from the front surface of the second negative lens (5) to the rear surface of the third positive lens (4) of 8.35 mm. The third negative lens (6) has a refractive index of 1.5, an Abbe number of 61, a focal length of f6 of -175.68 mm, a radius of curvature of R11 on the front surface of -103.39 mm, a radius of curvature of R12 on the rear surface of 757.56 mm, and a thickness of t6 of 7.5 mm. The distance d5 from the front surface of the third negative lens (6) to the rear surface of the second negative lens (5) is 95.27 mm. The distance d6 from the rear surface of the third negative lens (6) to the image plane (7) is 7 mm.

7. The low-cost, small-scale, wide-area optical system for detecting space debris according to claim 5, characterized in that: The focal length f is 200mm; The first positive lens (1) has a refractive index of 1.65, an Abbe number of 82, a focal length of f1 of 353.06 mm, a radius of curvature R1 of the front surface of 153.71 mm, a flat rear surface, and a thickness of t1 of 19.63 mm. The first negative lens (2) has a refractive index of 1.43, an Abbe number of 45, a focal length of f2 of -236.96 mm, a radius of curvature of R3 on the front surface of 262.59 mm, a radius of curvature of R4 on the rear surface of 93.69 mm, a thickness of t2 of 15.99 mm, and a distance d1 from the front surface of the first negative lens (2) to the rear surface of the first positive lens (1) of 31.34 mm. The second positive lens (3) has a refractive index of 1.44, an Abbe number of 81, a focal length of f3 of 156.64 mm, a radius of curvature of R5 on the front surface of 109.82 mm, a radius of curvature of R6 on the rear surface of -166.05 mm, a thickness of t3 of 24 mm, and a distance d2 from the front surface of the second positive lens (3) to the rear surface of the first negative lens (2) of 38.58 mm. The third positive lens (4) has a refractive index of 1.4, an Abbe number of 80, a focal length of f4 of 263.47 mm, a radius of curvature R7 of the front surface of -573.37 mm, a radius of curvature R8 of the rear surface of -97.45 mm, a thickness of t4 of 20 mm, and a distance d3 from the front surface of the third positive lens (4) to the rear surface of the second positive lens (3) of 46.7 mm. The material of the second negative lens (5) has a refractive index of 1.6, an Abbe number of 37, a focal length of f5 of -439.6 mm, a radius of curvature of R9 on the front surface of -77.52 mm, a radius of curvature of R10 on the rear surface of -112.38 mm, a thickness of t5 of 12 mm, and a distance d4 from the front surface of the second negative lens (5) to the rear surface of the third positive lens (4) of 6.6 mm. The third negative lens (6) has a refractive index of 1.55, an Abbe number of 65, a focal length of f6 of -140.54 mm, a radius of curvature of R11 on the front surface of -82.46 mm, a radius of curvature of R12 on the rear surface of 618.5 mm, and a thickness of t6 of 6 mm. The distance d5 from the front surface of the third negative lens (6) to the rear surface of the second negative lens (5) is 76.54 mm. The distance d6 from the rear surface of the third negative lens (6) to the image plane (7) is 6.6 mm.

8. A low-cost, small-scale, wide-area optical system for detecting space debris according to claim 6 or 7, characterized in that: The front surface of the first positive lens (1) is a high-order aspherical surface, as expressed below: ； Where K = -1.7003, A = -8.4025e-009, B = -1.3796e-012, C = -3.3116e-017, z is the aspherical sag for different apertures, c is the aspherical curvature, r is the aspherical aperture, K is the quadratic surface coefficient, and A, B, and C are the coefficients of higher-order terms of higher-order aspherical surfaces.

Images