Large-view-field space camera optical lens

Abstract

The invention provides a large-view-field space camera optical lens. An optical system of the optical lens comprises a front lens group, a diaphragm and a rear lens group which are sequentially arranged from an object side surface to an image side surface; the front lens group comprises a first negative meniscus lens, a first biconcave lens, a first positive meniscus lens, a first biconvex lens and a second positive meniscus lens which are sequentially arranged from the object side surface to the image side surface; and the rear lens group comprises a second biconvex lens, a second negative meniscus lens, a third negative meniscus lens, a third biconvex lens, a fourth negative meniscus lens, a fourth biconvex lens and a first optical filter which are sequentially arranged from the object side surface to the image side surface. Through cooperation of the aspherical lens of the first negative meniscus lens, the plurality of positive and negative meniscus lenses and the plurality of concave and convex lenses, the number of lenses used in the front lens group is reduced, the aberration correction difficulty of the rear lens group is reduced, and the lens has the performances of circular light spots, large view fields, low chromatic aberration, high resolution, small light spot form deviation in each view field, small image quality change under each temperature condition and the like.

Description

Technical Field

[0001] The present invention relates to the field of imaging lenses, and in particular to an optical lens for a space camera with a large field of view. Background Art

[0002] As humans continue to explore space, space optical technology has achieved unprecedented development, and more and more space targets need to be detected and tracked. As a payload carried on a satellite platform, space cameras have a special observation position and can detect and track from a multi-dimensional perspective in space. They have the characteristics of high precision and high reliability, and have been widely used in space missions.

[0003] The existing Chinese patent with publication number CN107229107A discloses an optical imaging lens and an imaging device. The optical imaging lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens and an eleventh lens arranged coaxially in sequence along the incident direction of light.

[0004] Limited by the development of hardware systems and software algorithms, the field of view of domestically developed space cameras in the field of space detection is not large. Various space detection optical lenses based on existing technologies cannot simultaneously achieve the performance indicators of large imaging field of view, high imaging resolution, good image surface diffuse spot morphology, and image quality not affected by temperature changes. With the rapid development of my country's aerospace technology, higher technical requirements are put forward for the detection accuracy of space cameras. Therefore, designing a large field of view space camera optical lens is of great significance to the field of space target detection.

[0005] Therefore, it is necessary to provide an optical lens with a circular light spot, a large field of view, low chromatic aberration, high resolution, small deviation in the shape of the light spots in each field of view, and small changes in image quality under various temperature conditions. Summary of the invention

[0006] In view of the defects in the prior art, an object of the present invention is to provide an optical lens for a space camera with a large field of view.

[0007] According to an optical lens for a space camera with a large field of view provided by the present invention, the optical system of the optical lens comprises a front lens group, an aperture and a rear lens group arranged in sequence from the object side to the image side;

[0008] The front lens group includes: a first negative meniscus lens, a first biconcave lens, a first positive meniscus lens, a first biconvex lens and a second positive meniscus lens, which are arranged in sequence from the object side to the image side;

[0009] The rear lens group includes a second biconvex lens, a second negative meniscus lens, a third negative meniscus lens, a third biconvex lens, a fourth negative meniscus lens, a fourth biconvex lens and a first filter, which are arranged in sequence from the object side to the image side.

[0010] Preferably, the front surface of the first negative meniscus lens is an aspherical lens, and the back surface is a spherical lens.

[0011] Preferably, the first biconcave lens, the first positive meniscus lens, the first biconvex lens, the second positive meniscus lens, the second biconvex lens, the second negative meniscus lens, the third negative meniscus lens, the third biconvex lens, the fourth negative meniscus lens, the fourth biconvex lens and the first filter are all spherical lenses.

[0012] Preferably, the air gap between the front lens group and the rear lens group is 3.mm-5.86mm.

[0013] Preferably, the air gap between the front lens group and the aperture is 3.09 mm-5.49 mm.

[0014] Preferably, the air gap between the rear lens group and the aperture is 0.23 mm-0.37 mm.

[0015] Preferably, the air gap between the first negative meniscus lens and the first biconcave lens is 2.92 mm-5.26 mm;

[0016] The air gap between the first biconcave lens and the first positive meniscus lens is 1.58 mm-3.26 mm;

[0017] The air gap between the first positive meniscus lens and the first biconvex lens is 0.23 mm-0.37 mm;

[0018] The air space between the first biconvex lens and the second positive meniscus lens is 1.mm-2.25mm.

[0019] Preferably, the air gap between the second biconvex lens and the second negative meniscus lens is 0.59 mm-0.89 mm;

[0020] The air gap between the second negative meniscus lens and the third negative meniscus lens is 0.23 mm-0.37 mm;

[0021] The air gap between the third negative meniscus lens and the third biconvex lens is 0.23 mm-0.37 mm;

[0022] The air gap between the third biconvex lens and the fourth negative meniscus lens is 0.58 mm-0.82 mm;

[0023] The air gap between the fourth negative meniscus lens and the fourth biconvex lens is 0.23 mm-0.37 mm;

[0024] The air gap between the fourth biconvex lens and the first filter is 1.13 mm-2.87 mm.

[0025] Preferably, at a half field of view of 60° and at 100 lp / mm, the optical transfer function of the optical lens is greater than 0.7 except for the edge field of view of 0.25-0.3.

[0026] Preferably, the optical lens structure is made of aluminum alloy material.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention reduces the number of lenses used in the front lens group and reduces the difficulty of correcting aberrations in the rear lens group through the coordination of an aspherical lens of a first negative meniscus lens, multiple positive and negative meniscus lenses, and multiple concave and convex lenses, thereby effectively controlling the lateral size and weight of the optical lens, having excellent properties such as a circular light spot, a large field of view, low chromatic aberration, high resolution, small deviation in the shape of light spots in each field of view, and small change in image quality under various temperature conditions, and can achieve the purpose of low cost requirements and mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0030] Figure 1 The present invention mainly embodies the optical system structure schematic diagram of the optical lens;

[0031] Figure 2 The optical transfer function diagram of the optical system of the optical lens mainly embodies the present invention;

[0032] Figure 3 This is a point diagram of the optical system of the optical lens mainly embodied in the present invention at 20°C;

[0033] Figure 4 This is a point diagram of the optical system of the optical lens mainly embodied in the present invention at -40°C;

[0034] Figure 5 This is a point diagram of the optical system of the optical lens mainly embodied in the present invention at 60°C;

[0035] Figure 6 This is a chromatic aberration diagram of the optical system of the optical lens mainly embodied in the present invention.

[0036] As shown in the figure:

[0037] Front lens group 10 Rear lens group 20 First negative meniscus lens 31

[0038] The second negative meniscus lens 32 The third negative meniscus lens 33 The fourth negative meniscus lens 34

[0039] First positive meniscus lens 41 Second positive meniscus lens 42 First biconcave lens 51

[0040] First biconvex lens 61 Second biconvex lens 62 Third biconvex lens 63

[0041] Fourth biconvex lens 64 First filter 71 Diaphragm 80

[0042] Image plane 90 DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0044] like Figure 1 As shown, according to an optical lens for a space camera with a large field of view provided by the present invention, the optical system of the optical lens includes a front lens group 10, an aperture 80 and a rear lens group 20 arranged in sequence from the object side to the image side; the front lens group 10 includes: a first negative meniscus lens 31, a first biconcave lens 51, a first positive meniscus lens 41, a first biconvex lens 61 and a second positive meniscus lens 42 arranged in sequence from the object side to the image side; the rear lens group 20 includes a second biconvex lens 62, a second negative meniscus lens 32, a third negative meniscus lens 33, a third biconvex lens 63, a fourth negative meniscus lens 34, a fourth biconvex lens 64 and a first filter 71 arranged in sequence from the object side to the image side; an image plane 90 is also arranged on the side of the rear lens group 20 away from the front lens group 10. The direction from the object side to the image side is Figure 1 The incident direction of light from left to right.

[0045] The front surface of the first negative meniscus lens 31 is an aspherical lens, and the rear surface is a spherical lens. The first biconcave lens 51, the first positive meniscus lens 41, the first biconvex lens 61, the second positive meniscus lens 42, the second biconvex lens 62, the second negative meniscus lens 32, the third negative meniscus lens 33, the third biconvex lens 63, the fourth negative meniscus lens 34, the fourth biconvex lens 64 and the first filter 71 are all spherical lenses. Preferably, the above-mentioned spherical lens is a spherical glass lens with high transmittance, and further a high transmittance glass material such as fused quartz and calcium fluoride, which can be domestically produced. Without coating, the average transmittance of the optical system is higher than 80%, which reduces the cost of mass production.

[0046] The optical lens of the present application reduces the number of lenses used in the front lens group 10 and the difficulty of correcting aberrations in the rear lens group 20 through the cooperation of the aspherical lens of the first negative meniscus lens 31, multiple positive and negative meniscus lenses, and multiple concave and convex lenses, thereby effectively controlling the lateral size and weight of the optical lens and providing an optical lens with a circular light spot, a large field of view, low chromatic aberration, high resolution, small deviation in the shape of each light spot in the field of view, and small change in image quality under different temperature conditions.

[0047] The air gap between the front lens group 10 and the rear lens group 20 is 3.32 mm-5.86 mm.

[0048] The air gap between the front lens group 10 and the aperture 80 is 3.09 mm-5.49 mm.

[0049] The air gap between the rear lens group 20 and the aperture 80 is 0.23 mm-0.37 mm.

[0050] The air gap between the first negative meniscus lens 31 and the first biconcave lens 51 is 2.92mm-5.26mm; the air gap between the first biconcave lens 51 and the first positive meniscus lens 41 is 1.58mm-3.26mm; the air gap between the first positive meniscus lens 41 and the first biconvex lens 61 is 0.23mm-0.37mm; the air gap between the first biconvex lens 61 and the second positive meniscus lens 42 is 1.33mm-2.25mm.

[0051] The air gap between the second biconvex lens 62 and the second negative meniscus lens 32 is 0.59mm-0.89mm; the air gap between the second negative meniscus lens 32 and the third negative meniscus lens 33 is 0.23mm-0.37mm; the air gap between the third negative meniscus lens 33 and the third biconvex lens 63 is 0.23mm-0.37mm; the air gap between the third biconvex lens 63 and the fourth negative meniscus lens 34 is 0.58mm-0.82mm; the air gap between the fourth negative meniscus lens 34 and the fourth biconvex lens 64 is 0.23mm-0.37mm; the air gap between the fourth biconvex lens 64 and the first filter 71 is 1.13mm-2.87mm.

[0052] At a half field of view of 60° and 100lp / mm, the optical transfer function of the optical lens is greater than 0.7 except for the edge field of view which is 0.25-0.3.

[0053] The optical lens of the present application can be used to develop a large-field-of-view space camera, with a large field of view (half field of view is 60°), a chromatic aberration of less than 1.1 μm, an optical MTF greater than 0.7 at 100 lp / mm except for the edge field of view of 0.25-0.3, an image plane spot radius RMS of less than 2 μm at 20°C, and little change in image quality under various temperature conditions.

[0054] The optical lens structure is made of aluminum alloy and has a heat-free design.

[0055] In a specific embodiment of the present application, the air gap between the front lens group 10 and the rear lens group 20 is 4.59 mm; the air gap between the front lens group 10 and the aperture 80 is 4.29 mm; the air gap between the aperture 80 and the rear lens group 20 is 0.3 mm; the air gap between the first negative meniscus lens 31 and the first biconcave lens 51 is 4.09 mm; the air gap between the first biconcave lens 51 and the first positive meniscus lens 41 is 2.42 mm; the air gap between the first positive meniscus lens 41 and the first biconvex lens 61 is 0.3 mm; the air gap between the first biconvex lens 61 and the second positive meniscus lens 42 is 0.3 mm. The air gap between them is 1.79mm; the air gap between the second biconvex lens 62 and the second negative meniscus lens 32 is 0.74mm; the air gap between the second negative meniscus lens 32 and the third negative meniscus lens 33 is 0.3mm; the air gap between the third negative meniscus lens 33 and the third biconvex lens 63 is 0.3mm; the air gap between the third biconvex lens 63 and the fourth negative meniscus lens 34 is 0.7mm; the air gap between the fourth negative meniscus lens 34 and the fourth biconvex lens 64 is 0.3mm; the air gap between the fourth biconvex lens 64 and the first filter 71 is 2mm.

[0056] like Figure 2As shown, it is the transfer function of the optical lens in this application. It can be seen that at a half field of view of 60° (full field of view of 120°), at 100lp / mm, the optical transfer function MTF is greater than 0.7 except for the edge field of view of 0.25-0.3.

[0057] like Figure 3 As shown, it is the spot diagram of the optical lens in this application at 20°C. It can be seen that the roundness of the image spot is very good, and the RMS of the spot radius is less than 2μm.

[0058] like Figure 4 As shown, it is a spot diagram of the optical lens in this application at -40°C, and it can be seen that the image spot has a very good roundness, and the spot radius RMS is less than 2.1μm. Compared with the 20°C working condition, the RMS changes by 5%.

[0059] like Figure 5 As shown, it is a spot diagram of the optical lens in this application at 60°C, and it can be seen that the image spot has a very good roundness, and the spot radius RMS is less than 2.1μm. Compared with the 20°C working condition, the RMS changes by 5%.

[0060] like Figure 6 As shown, it is a chromatic aberration diagram of the optical lens in this application. It can be seen that at a half field of view of 60° (full field of view of 120°), the absolute value of the chromatic aberration does not exceed 1.1 μm.

[0061] from Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 It can be seen that the optical lens aberration is well corrected, and the optical MTF is greater than 0.7 except for the edge field of view, and is relatively uniform, with small chromatic aberration, good spot roundness, and small image quality changes under various temperature conditions. The imaging quality requirements of the 2 / 3-inch SmartSens 350 detector (3 million pixels, 4.2μm pixel imaging) can be achieved at the full field of view. The full spherical lens element also provides convenience for mass production and reduces costs.

[0062] The optical system in the optical lens of the present application achieves the following optical indicators:

[0063] (1) Relative aperture: D / f' = 1 / 2.8; (2) Field of view: 2ω = 120°; (3) Spectral range: 500nm-800nm; (4) Resolution: 2 / 3 inch is better than 3 million pixels.

[0064] The optical lens of the large-field-of-view space camera of the present application has excellent properties such as circular light spot, large field of view, low chromatic aberration, high resolution, small deviation of the light spot shape of each field of view, and small change of image quality under various temperature conditions; it can be used in conjunction with 2 / 3-inch high-definition megapixel detectors of various formats such as 16:9 and 5:4, and can achieve the purpose of low cost requirements and mass production.

[0065] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0066] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. An optical lens for a large field of view space camera, characterized in that: The optical system of the optical lens comprises a front lens group (10), a stop (80) and a rear lens group (20) which are arranged in sequence from the object side to the image side; The front lens group (10) comprises, arranged in sequence from the object side to the image side: a first negative meniscus lens (31), a first biconcave lens (51), a first positive meniscus lens (41), a first biconvex lens (61), and a second positive meniscus lens (42); The rear lens group (20) comprises a second biconvex lens (62), a second negative meniscus lens (32), a third negative meniscus lens (33), a third biconvex lens (63), a fourth negative meniscus lens (34), a fourth biconvex lens (64) and a first filter (71) which are arranged in sequence from the object side to the image side.

2. The optical lens for a large-field-of-view space camera according to claim 1, characterized in that: The front surface of the first negative meniscus lens (31) is an aspherical lens, and the rear surface is a spherical lens.

3. The optical lens for a large-field-of-view space camera according to claim 1, wherein: The first biconcave lens (51), the first positive meniscus lens (41), the first biconvex lens (61), the second positive meniscus lens (42), the second biconvex lens (62), the second negative meniscus lens (32), the third negative meniscus lens (33), the third biconvex lens (63), the fourth negative meniscus lens (34), the fourth biconvex lens (64) and the first filter (71) are all spherical lenses.

4. The optical lens for a large-field-of-view space camera according to claim 1, wherein: The air gap between the front lens group (10) and the rear lens group (20) is 3.32 mm to 5.86 mm.

5. The optical lens for a large-field-of-view space camera according to claim 1, wherein: The air gap between the front lens group (10) and the aperture (80) is 3.09 mm to 5.49 mm.

6. The optical lens for a large-field-of-view space camera according to claim 1, characterized in that: The air gap between the rear lens group (20) and the aperture (80) is 0.23 mm to 0.37 mm.

7. The optical lens for a large-field-of-view space camera according to claim 1, wherein: The air gap between the first negative meniscus lens (31) and the first biconcave lens (51) is 2.92 mm-5.26 mm; The air gap between the first biconcave lens (51) and the first positive meniscus lens (41) is 1.58 mm to 3.26 mm; The air gap between the first positive meniscus lens (41) and the first biconvex lens (61) is 0.23 mm to 0.37 mm; The air gap between the first biconvex lens (61) and the second positive meniscus lens (42) is 1.33 mm-2.25 mm.

8. The optical lens for a large-field-of-view space camera according to claim 1, wherein: The air gap between the second biconvex lens (62) and the second negative meniscus lens (32) is 0.59 mm-0.89 mm; The air gap between the second negative meniscus lens (32) and the third negative meniscus lens (33) is 0.23 mm-0.37 mm; The air gap between the third negative meniscus lens (33) and the third biconvex lens (63) is 0.23 mm to 0.37 mm; The air gap between the third biconvex lens (63) and the fourth negative meniscus lens (34) is 0.58 mm-0.82 mm; The air gap between the fourth negative meniscus lens (34) and the fourth biconvex lens (64) is 0.23 mm to 0.37 mm; The air gap between the fourth biconvex lens (64) and the first filter (71) is 1.13 mm-2.87 mm.

9. The optical lens for a large-field-of-view space camera according to claim 1, wherein: At a half field of view of 60° and at 100 lp / mm, the optical transfer function of the optical lens is greater than 0.7 except for the edge field of view which is 0.25-0.

3.

10. The optical lens for a large-field-of-view space camera according to claim 1, wherein: The optical lens structure is made of aluminum alloy material.

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