A spaceflight-grade near-field rendezvous and docking (TOF) optical system

Abstract

The application discloses a space-grade near-field rendezvous and docking TOF optical system, which comprises, from the object side to the image side, an object side lens group, an aperture stop, an image side lens group and a photosensitive imaging surface; the object side lens group performs aperture contraction on incident light; the aperture stop adjusts the light flux by adjusting the aperture size arranged thereon; the image side lens group further focuses the light, corrects aberration and then projects the light onto the photosensitive imaging surface to form a final image; the object side lens group comprises, from the object side to the image side, a first negative meniscus lens, a second negative meniscus lens, a first double convex lens and a first positive meniscus lens; and the image side lens group comprises, from the object side to the image side, a first filter, a third negative meniscus lens, a second positive meniscus lens, a second double convex lens, a first plano-convex lens and a first plano-concave lens. The optical system provided by the application can realize high-precision imaging of a near-field target and has a guiding effect on the improvement of imaging precision in rendezvous and docking.

Description

Technical Field

[0001] This invention relates to the field of imaging lens technology, and in particular to an aerospace-grade near-field rendezvous and docking TOF optical system. Background Technology

[0002] Space rendezvous and docking technology is attracting increasing attention due to its crucial role in building large space stations, providing personnel and supplies, and transporting scientific instruments. Among these technologies, optical rendezvous and docking technology uses an optical system to image a target, measures its centroid, and then calculates the relative attitude of the target and tracking spacecraft. This technology boasts advantages such as high aiming accuracy, strong anti-interference capabilities, low accident risk, and the ability to operate unmanned. my country's research in this field started relatively late, and to keep pace with international developments in space rendezvous and docking, it is urgently necessary to conduct further research in this area.

[0003] Currently, there are many difficulties in developing optical systems for near-field rendezvous and docking of spacecraft based on TOF (Time of Flight) imaging technology, making it impossible to achieve the technical goals of high resolution, large field of view, high imaging quality, low distortion, and high-precision imaging of near-field targets.

[0004] Therefore, there is an urgent need to develop an aerospace-grade near-field rendezvous and docking optical system that can overcome the above-mentioned technical defects. Summary of the Invention

[0005] The purpose of this invention is to provide an aerospace-grade TOF optical system for near-field rendezvous and docking, which can solve the problems of low resolution, small field of view, low imaging quality, and large distortion that occur in near-field rendezvous and docking.

[0006] To achieve the above objectives, the present invention provides a space-grade near-field rendezvous and docking TOF optical system, comprising:

[0007] The object-side lens group, the aperture, the image-side lens group, and the photosensitive imaging surface are arranged sequentially from the object-side to the image-side.

[0008] The object-side lens group reduces the aperture of the incident light;

[0009] The aperture is provided with an adjustable aperture structure, and the light flux can be adjusted by adjusting the size of the aperture.

[0010] The image-side lens group further focuses the light passing through the object-side lens group, corrects aberrations, and then projects it onto the photosensitive imaging surface to sense light and form the final image.

[0011] The object-side lens group comprises: a first negative meniscus lens, a second negative meniscus lens, a first biconvex lens, and a first positive meniscus lens arranged sequentially from the object-side to the image-side.

[0012] The image-side lens group includes: a first filter, a third negative meniscus lens, a second positive meniscus lens, a second biconvex lens, a first plano-convex lens, and a first plano-concave lens arranged sequentially from the object side to the image side.

[0013] Optionally, the air gap between the object-side lens group and the image-side lens group is 6.33mm-9.27mm.

[0014] Optionally, the air gap between the object-side lens group and the aperture is 6.33mm-9.17mm.

[0015] Optionally, the air gap between the aperture and the image-side lens group is 0mm-0.1mm.

[0016] Optionally, the air gap between the first negative meniscus lens and the second negative meniscus lens is 5.64mm-7.44mm; the air gap between the second negative meniscus lens and the first biconvex lens is 6.17mm-8.73mm; and the air gap between the first biconvex lens and the first positive meniscus lens is 2.45mm-3.83mm.

[0017] Optionally, the air gap between the first filter and the third negative meniscus lens is 6.86mm-10.18mm; the air gap between the third negative meniscus lens and the second positive meniscus lens is 0.37mm-0.57mm; the air gap between the second positive meniscus lens and the second biconvex lens is 0.25mm-0.37mm; the air gap between the second biconvex lens and the first plano-convex lens is 0.25mm-0.35mm; and the air gap between the first plano-convex lens and the first plano-concave lens is 2.18mm-3.66mm.

[0018] Optionally, the first negative meniscus lens, the second negative meniscus lens, the first biconvex lens, and the first positive meniscus lens are all spherical lenses.

[0019] Optionally, the first filter, the third negative meniscus lens, the second positive meniscus lens, the second biconvex lens, the first plano-convex lens, and the first plano-concave lens are all spherical lenses.

[0020] Optionally, when the object height is 8 mm and the spatial frequency is 50 lp / mm, the optical transfer function of the optical system is greater than 0.4 when the object is 1 m away; greater than 0.6 when the object is 2 m away; and greater than 0.4 when the object is 10 m away.

[0021] Optionally, when the object is 2m away, the optical system has an optical transfer function greater than 0.6, an edge relative illumination greater than 50%, a spot radius RMS less than 4μm, a field curvature value less than 0.15mm, and a relative distortion value less than 1.5%.

[0022] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention provides an aerospace-grade near-field rendezvous and docking TOF optical system, which effectively reduces the aperture of incident light in a large field of view through the cooperation of multiple positive and negative meniscus lenses, multiple concave and convex lenses and filters, and reduces the difficulty of correcting aberrations by the image-side lens group. At the same time, it realizes the miniaturization and weight reduction of the lens of the near-field rendezvous and docking TOF optical system.

[0024] 2. The aerospace-grade near-field rendezvous and docking TOF optical system provided by this invention has the characteristics of large field of view, low distortion, high resolution, long working distance, and uniform relative illumination.

[0025] 3. The present invention provides an aerospace-grade near-field rendezvous and docking TOF optical system, which can realize high-precision imaging of near-field targets and has a guiding role in improving imaging accuracy during the rendezvous and docking process. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the optical system of the present invention;

[0027] Figure 2 This is a graph showing the optical transfer function of the optical system of the present invention located at 1 meter.

[0028] Figure 3 The optical transfer function diagram of the optical system of the present invention located at 2 meters is shown.

[0029] Figure 4 This is a graph of the optical transfer function of the optical system of the present invention located at 10 meters.

[0030] Figure 5 This is a relative illumination diagram of the optical system of the present invention located at 1 meter.

[0031] Figure 6 This is a relative illumination diagram of the optical system of the present invention located at 2 meters.

[0032] Figure 7 This is a relative illumination diagram of the optical system of the present invention located at 10 meters.

[0033] Figure 8 This is a point diagram of the optical system of the present invention located at 1 meter.

[0034] Figure 9 This is a point diagram of the optical system of the present invention located at 2 meters;

[0035] Figure 10 This is a point diagram of the optical system of the present invention located at 10 meters;

[0036] Figure 11 Figure (a) is a field curve diagram of the optical system of the present invention located at 1 meter. Figure 11 Figure (b) shows the relative distortion of the object at 1 meter.

[0037] Figure 12 Figure (a) in the figure is a field curve diagram of the optical system of the present invention located at 2 meters; Figure 12 Figure (b) shows the relative distortion of the object at a distance of 2 meters.

[0038] Figure 13 Figure (a) shows the field curvature of the optical system of the present invention located at 10 meters. Figure 13 Figure (b) shows the relative distortion of the object at a distance of 10 meters. Detailed Implementation

[0039] The following will be combined with the appendix Figures 1-13 The technical content, structural features, objectives and effects of the present invention will be described in detail through preferred embodiments.

[0040] It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions. They are only used to facilitate and clarify the purpose of illustrating the embodiments of the present invention, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationship, or adjustments to the size should still fall within the scope of the technical content disclosed in the present invention, provided that they do not affect the effects and objectives that the present invention can produce.

[0041] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] This invention provides a space-grade near-field rendezvous and docking TOF optical system, such as... Figure 1 As shown, the near-field rendezvous and docking TOF optical system includes: an object-side lens group 10, an aperture 90, an image-side lens group 20, and a photosensitive imaging surface 100, arranged sequentially from the object side to the image side, i.e., from left to right in the figure. The object-side lens group 10 is the part of the near-field rendezvous and docking TOF optical system closest to the object, and can reduce the aperture of the incident light. The aperture 90 has an adjustable aperture structure, which can adjust the light flux by adjusting the size of the aperture. The image-side lens group 20 further focuses the light passing through the object-side lens group 10, corrects aberrations, and then projects it onto the photosensitive imaging surface (100) for photosensitive sensing and to form the final image.

[0044] The air gap between the object-side lens group 10 and the image-side lens group 20 is 6.33mm-9.27mm. Further, the air gap between the object-side lens group 10 and the aperture 90 is 6.33mm-9.17mm; the air gap between the aperture 90 and the image-side lens group 20 is 0mm-0.1mm.

[0045] The object-side lens group 10 includes: a first negative meniscus lens 31, which is the lens closest to the object-side surface; a second negative meniscus lens 32, which is disposed on the side of the first positive meniscus lens 31 away from the object-side surface; a first biconvex lens 51, which is disposed on the side of the second negative meniscus lens 32 away from the object-side surface; and a first positive meniscus lens 41, which is disposed on the side of the first biconvex lens 51 away from the object-side surface. Therefore, from the object-side surface to the aperture stop 90, the first negative meniscus lens 31, the second negative meniscus lens 32, the first biconvex lens 51, and the first positive meniscus lens 41 are arranged sequentially.

[0046] The air gap between the first negative meniscus lens 31 and the second negative meniscus lens 32 is 5.64mm-7.44mm; the air gap between the second negative meniscus lens 32 and the first biconvex lens 51 is 6.17mm-8.73mm; and the air gap between the first biconvex lens 51 and the first positive meniscus lens 41 is 2.45mm-3.83mm.

[0047] In a specific embodiment of the present invention, the first negative meniscus lens 31, the second negative meniscus lens 32, the first biconvex lens 51, and the first positive meniscus lens 41 are all spherical lenses. Furthermore, the spherical lenses are made of high-transmittance spherical glass. Preferably, the spherical lenses of the present invention are made of glass materials such as fused silica and calcium fluoride, and without coating, the average transmittance of the optical system is higher than 75%.

[0048] The image-side lens group 20 includes: a first filter 61 disposed on the side of the aperture stop 90 away from the object side; a third negative meniscus lens 33 disposed on the side of the first filter 61 away from the object side; a second positive meniscus lens 42 disposed on the side of the third negative meniscus lens 33 away from the object side; a second biconvex lens 52 disposed on the side of the second positive meniscus lens 42 away from the object side; a first plano-convex lens 71 disposed on the side of the second biconvex lens 52 away from the object side; and a first plano-concave lens 81 disposed on the side of the first plano-convex lens 71 away from the object side. Therefore, from the aperture stop 90 to the photosensitive imaging surface 100, the first filter 61, the third negative meniscus lens 33, the second positive meniscus lens 42, the second biconvex lens 52, the first plano-convex lens 71, and the first plano-concave lens 81 are sequentially arranged.

[0049] The air gap between the first filter 61 and the third negative meniscus lens 33 is 6.86mm-10.18mm; the air gap between the third negative meniscus lens 33 and the second positive meniscus lens 42 is 0.37mm-0.57mm; the air gap between the second positive meniscus lens 42 and the second biconvex lens 52 is 0.25mm-0.37mm; the air gap between the second biconvex lens 52 and the first plano-convex lens 71 is 0.25mm-0.35mm; and the air gap between the first plano-convex lens 71 and the first plano-concave lens 81 is 2.18mm-3.66mm.

[0050] In a specific embodiment of the present invention, the first filter 61, the third negative meniscus lens 33, the second positive meniscus lens 42, the second biconvex lens 52, the first plano-convex lens 71, and the first plano-concave lens 81 are all spherical lenses. Furthermore, the spherical lenses are high-transmittance spherical glass lenses. Preferably, the spherical lenses of the present invention are made of glass materials such as fused silica and calcium fluoride, and without coating, the average transmittance of the optical system is higher than 75%.

[0051] In a more specific embodiment, the air gap between the object-side lens group 10 and the image-side lens group 20 is 7.75 mm. Specifically, the air gap between the object-side lens group 10 and the aperture 90 is 7.75 mm; the air gap between the aperture 90 and the image-side lens group 20 is 0 mm, meaning the aperture 90 and the image-side lens group 20 are in contact. Further, the air gap between the first negative meniscus lens 31 and the second negative meniscus lens 32 is 6.54 mm; the air gap between the second negative meniscus lens 32 and the first biconvex lens 51 is 7.45 mm; and the air gap between the first biconvex lens 51 and the first positive meniscus lens 41 is 3.14 mm. The air gap between the first filter 61 and the third negative meniscus lens 33 is 8.52 mm; the air gap between the third negative meniscus lens 33 and the second positive meniscus lens 42 is 0.47 mm; the air gap between the second positive meniscus lens 42 and the second biconvex lens 52 is 0.31 mm; the air gap between the second biconvex lens 52 and the first plano-convex lens 71 is 0.30 mm; and the air gap between the first plano-convex lens 71 and the first plano-concave lens 81 is 2.92 mm.

[0052] In a specific embodiment of the present invention, when the object height is 8 mm and the spatial frequency is 50 lp / mm, the optical transfer function of the near-field rendezvous and docking TOF optical system is as follows: Figure 2 , Figure 3 and Figure 4 As shown. Figure 2 This indicates that when the object is located at a distance of 1 meter, the optical transfer function of this near-field rendezvous and docking TOF optical system is greater than 0.4. Figure 3 This indicates that when the object is located at a distance of 2 meters, the optical transfer function of this near-field rendezvous and docking TOF optical system is greater than 0.6. Figure 4 This indicates that when the object is located at a distance of 10 meters, the optical transfer function of this near-field rendezvous and docking TOF optical system is greater than 0.4.

[0053] The relative illuminance values ​​of the optical system of the present invention when the object is at a distance of 1 meter, 2 meters, and 10 meters are as follows: Figure 5 , Figure 6 and Figure 7 As shown, under the near-field rendezvous and docking TOF optical system, the relative illumination of the photosensitive imaging surface 100 remains uniform, and the relative illumination at the edges is greater than 50%.

[0054] like Figure 8 , Figure 9 and Figure 10The figures shown are dot plots of the near-field rendezvous and docking TOF optical system at object distances of 1 meter, 2 meters, and 10 meters. These dot plots show that the RMS radius of the blur spot on the photosensitive imaging surface 100 is less than 10 μm, especially when the object is 2 meters away, the RMS radius of the blur spot is less than 4 μm. These results indicate that the blur spot shape of the photosensitive imaging surface 100 of the near-field rendezvous and docking TOF optical system is good.

[0055] Figure 11 Figure (a) shows the field curvature of the near-field rendezvous and docking TOF optical system when the object is 1 meter away. Figure 11 Figure (b) shows the relative distortion values ​​of the near-field rendezvous and docking TOF optical system when the object is 1 meter away. Figure 11 As can be seen in Figure (a), the field curvature of this optical system is less than 0.15 mm; from Figure 11 As can be seen in Figure (b), the relative distortion of the optical system does not exceed 1.5%.

[0056] Figure 12 Figure (a) shows the field curvature of the near-field rendezvous and docking TOF optical system when the object is 2 meters away. Figure 12 Figure (b) shows the relative distortion values ​​of the near-field rendezvous and docking TOF optical system when the object is 2 meters away. Figure 12 As can be seen in Figure (a), the field curvature of this optical system is less than 0.15 mm; from Figure 12 As can be seen in Figure (b), the relative distortion of the optical system does not exceed 1.5%.

[0057] Figure 13 Figure (a) shows the field curvature of the near-field rendezvous and docking TOF optical system when the object is 10 meters away. Figure 13 Figure (b) shows the relative distortion of the near-field rendezvous and docking TOF optical system when the object is 10 meters away. Figure 13 As can be seen in Figure (a), the field curvature of this optical system is less than 0.15 mm; from Figure 13 As can be seen in Figure (b), the relative distortion of the optical system does not exceed 1.5%.

[0058] Therefore, when the object is 1 meter, 2 meters and 10 meters away, the field curvature of the near-field rendezvous and docking TOF optical system is less than 0.15 mm and the relative distortion value does not exceed 1.5%.

[0059] The near-field rendezvous and docking TOF optical system provided by this invention exhibits particularly outstanding optical performance when the object is 2 meters away. Specifically, its optical transfer function is greater than 0.6, the relative illumination of the photosensitive imaging surface 100 is uniform, the relative illumination at the edges is greater than 50%, and the relative distortion value is less than 1.5%.

[0060] In summary, the aforementioned near-field rendezvous and docking TOF optical system possesses the following characteristics: optical transfer function (OTF) greater than 0.4 for each field of view (especially greater than 0.6 when the object is located at 2 meters), relative illumination greater than 50%, RMS spot radius less than 10 μm (especially less than 4 μm when the object is located at 2 meters), field curvature less than 0.15 mm, and relative distortion not exceeding 1.5%. Furthermore, the global surface lens configuration provides the conditions for mass production of this near-field rendezvous and docking TOF optical system.

[0061] In addition, the near-field rendezvous and docking TOF optical system has the following optical specifications:

[0062] 1) Relative aperture: D / f′=1 / 5 (i.e., image-side F number is 5), where D is the entrance pupil diameter and f′ is the focal length of the lens;

[0063] 2) Large field of view: 2ω = 78°, where ω is the half field of view;

[0064] 3) Spectral range: 850nm ± 10nm;

[0065] 4) Resolution: Achieve imaging quality comparable to a 2 / 3-inch SmartSens 350 detector (3 megapixels, 4.2μm pixel imaging);

[0066] 5) Working distance: At a spatial frequency of 50 lp / mm, the working distance is 0.8 meters to ∞.

[0067] In summary, the aerospace-grade near-field rendezvous and docking TOF optical system provided by this invention has excellent performance in terms of large field of view, low distortion, high resolution, long working distance, and uniform relative illumination. In addition, it can be used with various 2 / 3-inch high-definition megapixel detectors of different aspect ratios such as 16:9 and 5:4, and can achieve the goals of low cost and mass production.

[0068] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A spaceflight-grade near-field rendezvous and docking (TOF) optical system, characterized by, The optical system consists of an object-side lens group (10), an aperture (90), an image-side lens group (20), and a photosensitive imaging surface (100), arranged sequentially from the object side to the image side. The object-side lens group (10) reduces the aperture of the incident light; The aperture (90) is provided with an adjustable aperture structure, and the light flux can be adjusted by adjusting the size of the aperture. The image-side lens group (20) further focuses the light passing through the object-side lens group (10), corrects aberrations, and then projects it onto the photosensitive imaging surface (100) for photosensitive sensing and to form the final image; The object-side lens group (10) consists of a first negative meniscus lens (31), a second negative meniscus lens (32), a first biconvex lens (51), and a first positive meniscus lens (41) arranged sequentially from the object-side to the image-side. The image-side lens group (20) consists of a first filter (61), a third negative meniscus lens (33), a second positive meniscus lens (42), a second biconvex lens (52), a first plano-convex lens (71), and a first plano-concave lens (81) arranged sequentially from the object side to the image side; The air gap between the object-side lens group (10) and the image-side lens group (20) is 6.33mm-9.27mm; The air gap between the object-side lens group (10) and the aperture (90) is 6.33mm-9.17mm; The air gap between the aperture stop (90) and the image-side lens group (20) is 0mm-0.1mm; The air gap between the first negative meniscus lens (31) and the second negative meniscus lens (32) is 5.64mm-7.44mm; the air gap between the second negative meniscus lens (32) and the first biconvex lens (51) is 6.17mm-8.73mm; the air gap between the first biconvex lens (51) and the first positive meniscus lens (41) is 2.45mm-3.83mm. The air gap between the first filter (61) and the third negative meniscus lens (33) is 6.86mm-10.18mm; the air gap between the third negative meniscus lens (33) and the second positive meniscus lens (42) is 0.37mm-0.57mm; the air gap between the second positive meniscus lens (42) and the second biconvex lens (52) is 0.25mm-0.37mm; the air gap between the second biconvex lens (52) and the first plano-convex lens (71) is 0.25mm-0.35mm; and the air gap between the first plano-convex lens (71) and the first plano-concave lens (81) is 2.18mm-3.66mm. The first negative meniscus lens (31) bends toward the object side; the second negative meniscus lens (32) bends toward the object side; the first positive meniscus lens (41) bends toward the image side; the third negative meniscus lens (33) bends toward the image side; and the second positive meniscus lens (42) bends toward the image side.

2. The near-field intersection docking (TOF) optical system of claim 1, wherein, The first negative meniscus lens (31), the second negative meniscus lens (32), the first biconvex lens (51) and the first positive meniscus lens (41) are all spherical lenses.

3. The near-field rendezvous and docking TOF optical system as described in claim 1, characterized in that, The first filter (61), the third negative meniscus lens (33), the second positive meniscus lens (42), the second biconvex lens (52), the first plano-convex lens (71) and the first plano-concave lens (81) are all spherical lenses.

4. The near-field rendezvous and docking TOF optical system as described in claim 1, characterized in that, With an object height of 8 mm and a spatial frequency of 50 lp / mm, the optical transfer function of the optical system is greater than 0.4 when the object is 1 m away; greater than 0.6 when the object is 2 m away; and greater than 0.4 when the object is 10 m away.

5. The near-field rendezvous and docking TOF optical system as described in claim 1, characterized in that, When the object is 2m away, the optical system has an optical transfer function greater than 0.6, an edge relative illumination greater than 50%, a diffuse spot radius (RMS) less than 4μm, a field curvature value less than 0.15mm, and a relative distortion value less than 1.5%.

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