Large dynamic star sensor optical lens

Abstract

The invention discloses a large dynamic star sensor optical lens which comprises a front lens group, a diaphragm, a rear lens group and an image surface which are sequentially arranged from an object side surface to an image side surface, the front lens group is used for collecting light rays, correcting aberration and forming an intermediate image; the diaphragm controls the luminous flux by adjusting the relative aperture of the diaphragm; the rear lens group amplifies the intermediate image, corrects aberration and forms a final image; the image surface performs optical imaging on the final image; wherein the front lens group comprises a first positive meniscus lens and a first biconvex lens which are sequentially arranged from the object side surface to the image side surface; and the rear lens group comprises a first biconcave lens, a second biconvex lens, a second positive meniscus lens, a first negative meniscus lens, a second biconcave lens and a first optical filter which are sequentially arranged from the object side surface to the image side surface. The optical lens provided by the invention has the characteristics of circular light spots, large relative aperture, low chromatic aberration, low distortion, high resolution and small light spot form and energy deviation after each field of view is defocused.

Description

Technical Field

[0001] The invention relates to the technical field of imaging lenses, in particular to an optical lens for a large dynamic star sensor. Background Art

[0002] Star sensors are low-light photoelectric sensors that observe starlight. They have been widely used in space missions due to their high precision and reliability. Limited by the development of hardware systems and software algorithms, the dynamic performance of domestically developed star sensors is not high and they are usually only used in the stable flight stage of the carrier.

[0003] With the rapid development of my country's aerospace technology, large dynamic carriers such as agile satellites and long-range weapons now put forward higher technical requirements for the dynamic performance of star sensors. However, the existing various optical lenses for star sensors cannot simultaneously meet the requirements of high imaging resolution, small image distortion, good image surface diffuse spot morphology, and high-precision extraction of star points under a large dynamic range. Therefore, designing a large dynamic star sensor optical lens is of great significance to the development of star sensors. Summary of the invention

[0004] The purpose of the present invention is to provide a large dynamic range star sensor optical lens, aiming to solve the problem that the existing star sensor optical lens cannot simultaneously meet the requirements of high imaging resolution, small image distortion, good image plane diffuse spot morphology and high-precision star point extraction under a large dynamic range.

[0005] To achieve the above object, the present invention provides a large dynamic star sensor optical lens, comprising: a front lens group, an aperture, a rear lens group and an image plane arranged in sequence from the object side to the image side; the front lens group collects light, corrects aberrations, and forms an intermediate image; the aperture controls the light flux by adjusting its relative aperture; the rear lens group magnifies the intermediate image, corrects aberrations, and forms a final image; the image plane performs optical imaging on the final image;

[0006] Wherein, the front lens group comprises: a first positive meniscus lens and a first biconvex lens arranged in sequence from the object side to the image side;

[0007] The rear lens group comprises: a first biconcave lens, a second biconvex lens, a second positive meniscus lens, a first negative meniscus lens, a second biconcave lens and a first filter which are arranged in sequence from the object side to the image side.

[0008] Optionally, the air gap between the front lens group and the rear lens group is 1.82mm-2.58mm.

[0009] Optionally, the air gap between the front lens group and the aperture is 0.37mm-0.63mm.

[0010] Optionally, the air gap between the aperture and the rear lens group is 1.45mm-1.95mm.

[0011] Optionally, the air gap between the first positive meniscus lens and the first biconvex lens is 0.37 mm-0.63 mm.

[0012] Optionally, the air gap between the first biconcave lens and the second biconvex lens is 5.6mm-11.2mm; the air gap between the second biconvex lens and the second positive meniscus lens is 6.2mm-11.8mm; the air gap between the second positive meniscus lens and the first negative meniscus lens is 1.8mm-2.6mm; the air gap between the first negative meniscus lens and the second biconcave lens is 0.8mm-1.2mm; the air gap between the second biconcave lens and the first filter is 1.8mm-2.6mm.

[0013] Optionally, the first positive meniscus lens and the first biconvex lens are both spherical lenses.

[0014] Optionally, the first biconcave lens, the second biconvex lens, the second positive meniscus lens, the first negative meniscus lens, the second biconcave lens and the first filter are all spherical lenses.

[0015] Optionally, the optical transfer function of the optical lens is greater than 0.4 at a half field of view of 7° and a spatial frequency of 100lp / mm.

[0016] Optionally, the relative distortion value of the optical lens is less than 0.05% at a half field of view of 7°.

[0017] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The optical lens of a large dynamic star sensor provided by the present invention reduces the number of lenses used in the front lens group and the difficulty of correcting aberrations of the rear lens group through the cooperation of multiple positive and negative meniscus lenses and multiple concave and convex lenses, thereby achieving miniaturization and lightweight of the lens.

[0019] 2. The large dynamic star sensor optical lens provided by the present invention has the characteristics of circular light spot, large relative aperture, low chromatic aberration, low distortion, high resolution, and small deviation of light spot shape and energy after defocusing in each field of view.

[0020] 3. The large dynamic star sensor optical lens provided by the present invention can realize high-precision extraction of the observed object by the large dynamic star sensor optical lens. This beneficial effect has a guiding role in improving the accuracy of the star sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1It is a schematic diagram of the composition of the optical lens of the present invention;

[0022] Figure 2 is an optical transfer function diagram of the optical lens of the present invention;

[0023] Figure 3 The field curvature diagram and distortion diagram of the optical lens of the present invention;

[0024] Figure 4 is a point diagram before defocusing of the optical lens of the present invention;

[0025] Figure 5 is a point diagram of the optical lens after defocusing of the present invention;

[0026] Figure 6 : is the chromatic aberration diagram of the optical lens of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the attached Figures 1 to 6 , the technical content, structural features, objectives achieved and effects of the present invention are described in detail through preferred embodiments.

[0028] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the embodiments of the present invention, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention.

[0029] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] The present invention provides a large dynamic star sensor optical lens, such as Figure 1 As shown, the optical lens of the large dynamic star sensor includes: a front lens group 10, a stop 80, a rear lens group 20 and an image plane 90, which are arranged in sequence from the object side to the image side, that is, from the left to the right in the figure. The front lens group 10 is the part closest to the object side in the optical system, and has the functions of collecting light, correcting aberrations, and forming an intermediate image; the stop 80 is used to control the light flux, which can be achieved by adjusting the relative aperture of the stop 80; the rear lens group 20 has the functions of magnifying the intermediate image, further correcting aberrations, and forming a final image; the image plane 90 is used for optical imaging.

[0032] The air gap between the front lens group 10 and the rear lens group 20 is 1.82 mm to 2.58 mm. Furthermore, the air gap between the front lens group 10 and the aperture 80 is 0.37 mm to 0.63 mm; and the air gap between the aperture 80 and the rear lens group 20 is 1.45 mm to 1.95 mm.

[0033] Among them, the front lens group 10 includes: a first positive meniscus lens 31, which is the lens closest to the side of the object and has the function of collecting light and preliminary imaging; a first biconvex lens 71, which is arranged between the first positive meniscus lens 31 and the aperture 80, and has the function of regulating the light path and optimizing the aberration.

[0034] The air gap between the first positive meniscus lens 31 and the first biconvex lens 71 is 0.37 mm-0.63 mm.

[0035] In a specific embodiment of the present invention, the first positive meniscus lens 31 and the first biconvex lens 71 are both spherical lenses. Further, the spherical lens is a spherical glass lens with high transmittance. Preferably, the spherical lens of the present invention is made of glass materials such as fused quartz and ZF6, and the average transmittance of the optical system is higher than 75% without coating.

[0036] The rear lens group 20 includes: a first biconcave lens 61, which is arranged on the side of the aperture 80 away from the object side; a second biconvex lens 72, which is arranged on the side of the first biconcave lens 61 away from the object side; a second positive meniscus lens 32, which is arranged on the side of the second biconvex lens 72 away from the object side; a first negative meniscus lens 41, which is arranged on the side of the second positive meniscus lens 32 away from the object side; a second biconcave lens 62, which is arranged on the side of the first negative meniscus lens 41 away from the object side; and a first filter 51, which is arranged on the side of the second biconcave lens 62 away from the object side to control the light intensity. Therefore, from the aperture 80 to the image plane 90, the first biconcave lens 61, the second biconvex lens 72, the second positive meniscus lens 32, the first negative meniscus lens 41, the second biconcave lens 62 and the first filter 51 are arranged in sequence.

[0037] Among them, the air gap between the first biconcave lens 61 and the second biconvex lens 72 is 5.6mm-11.2mm; the air gap between the second biconvex lens 72 and the second positive meniscus lens 32 is 6.2mm-11.8mm; the air gap between the second positive meniscus lens 32 and the first negative meniscus lens 41 is 1.8mm-2.6mm; the air gap between the first negative meniscus lens 41 and the second biconcave lens 62 is 0.8mm-1.2mm; the air gap between the second biconcave lens 62 and the first filter 51 is 1.8mm-2.6mm.

[0038] In a specific embodiment of the present invention, the first biconcave lens 61, the second biconvex lens 72, the second positive meniscus lens 32, the first negative meniscus lens 41, the second biconcave lens 62, and the first filter 51 are all spherical lenses. Further, the spherical lens adopts a spherical glass lens with high transmittance. Preferably, the spherical lens of the present invention is made of glass materials such as fused quartz and ZF6, and the average transmittance of the optical system is higher than 75% without coating.

[0039] In a more specific embodiment, the air gap between the front lens group 10 and the rear lens group 20 is 2.2 mm, the air gap between the front lens group 10 and the aperture 80 is 0.5 mm, and the air gap between the aperture 80 and the rear lens group 20 is 1.7 mm. Further, the air gap between the first positive meniscus lens 31 and the first biconvex lens 71 is 0.5 mm; the air gap between the first biconvex lens 71 and the aperture 80 is 0.5 mm; the air gap between the aperture 80 and the first biconcave lens 61 is 1.7 mm; the air gap between the first biconcave lens 61 and the second biconvex lens 72 is 8.4 mm; the air gap between the second biconvex lens 72 and the second positive meniscus lens 32 is 9.0 mm; the air gap between the second positive meniscus lens 32 and the first negative meniscus lens 41 is 2.2 mm; the air gap between the first negative meniscus lens 41 and the second biconcave lens 62 is 1.0 mm; the air gap between the second biconcave lens 62 and the first filter 51 is 2.2 mm.

[0040] like Figure 2 As shown, it is the optical transfer function of the optical lens of the large dynamic star sensor. Therefore, at a half field of view of 7° and a spatial frequency of 100lp / mm, the optical transfer function (MTF) is greater than 0.4.

[0041] like Figure 3 The figure shows the field curvature and relative distortion value of the large dynamic star sensor optical lens. In the field curvature diagram on the left, the vertical axis is the half field angle range, and the horizontal axis is the field curvature value, showing that the field curvature value of the large dynamic star sensor optical lens is less than 0.08mm; in the relative distortion diagram on the right, the vertical axis is the half field angle range, and the horizontal axis is the relative distortion percentage, showing that the absolute value of the relative distortion of the large dynamic star sensor optical lens does not exceed 0.05%.

[0042] like Figure 4 and Figure 5 As shown, it is the spot diagram of the large dynamic star sensor optical lens before and after defocusing. The RMS of the spot radius of different fields of view before defocusing is less than 6μm, and the RMS of the spot radius of different fields of view after defocusing is less than 10μm. After calculation, the average change of the RMS of the spot radius of different fields of view after defocusing is less than 47%. Therefore, the circularity of the image spot of the large dynamic star sensor optical lens before and after defocusing is very good.

[0043] like Figure 6 As shown, it is a chromatic aberration diagram of the large dynamic star sensor optical lens, the vertical axis is the half field angle range, and the horizontal axis is the chromatic aberration value, which shows that the absolute value of the chromatic aberration of the large dynamic star sensor optical lens does not exceed 0.5μm under the half field of view of 7°.

[0044] In summary, the large dynamic star sensor optical lens has the characteristics that the optical transfer function of each field of view is greater than 0.4, the relative distortion value is less than 0.05%, the image spot roundness before and after defocusing is good, and the chromatic aberration deviation is small. In addition, the setting of the full spherical lens also provides conditions for the large dynamic star sensor optical lens to achieve mass production.

[0045] In addition, the optical lens of the large dynamic star sensor has the following optical indicators:

[0046] 1) Large relative aperture: D / f′=1 / 2, where D is the lens entrance pupil diameter and f′ is the lens focal length;

[0047] 2) Field of view: 2ω=14 o ， Where ω is the half field of view;

[0048] 3) Spectral range: 600nm-1000nm;

[0049] 4) Resolution: The imaging quality reaches that of the 2 / 3-inch SmartSens 350 detector (3 million pixels, 4.2μm pixel imaging).

[0050] In summary, the optical lens for a large dynamic star sensor provided by the present invention has excellent properties such as a circular light spot, a large relative aperture, low chromatic aberration, low distortion, high resolution, and small deviation of the light spot shape and energy after defocusing in each field of view; and 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 also achieve the purpose of low cost and mass production.

[0051] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the invention. After reading the above content, it will be obvious to those skilled in the art for various modifications and substitutions of the present invention. Therefore, the protection scope of the present invention should be limited by the attached claims.

Claims

1. A large dynamic star sensor optical lens, characterized in that: The optical lens comprises: a front lens group (10), an aperture (80), a rear lens group (20) and an image plane (90) arranged in sequence from the object side to the image side; the front lens group (10) collects light, corrects aberrations, and forms an intermediate image; the aperture (80) controls the light flux by adjusting its relative aperture; the rear lens group (20) magnifies the intermediate image, corrects aberrations, and forms a final image; and the image plane (90) performs optical imaging on the final image; Wherein, the front lens group (10) comprises: a first positive meniscus lens (31) and a first biconvex lens (71) arranged in sequence from the object side to the image side; The rear lens group (20) comprises: a first biconcave lens (61), a second biconvex lens (72), a second positive meniscus lens (32), a first negative meniscus lens (41), a second biconcave lens (62) and a first filter (51) which are arranged in sequence from the object side to the image side.

2. The large dynamic star sensor optical lens according to claim 1, characterized in that: The air gap between the front lens group (10) and the rear lens group (20) is 1.82 mm to 2.58 mm.

3. The large dynamic star sensor optical lens according to claim 2, characterized in that: The air gap between the front lens group (10) and the aperture (80) is 0.37 mm to 0.63 mm.

4. The large dynamic star sensor optical lens according to claim 3, characterized in that: The air gap between the aperture (80) and the rear lens group (20) is 1.45 mm to 1.95 mm.

5. The large dynamic star sensor optical lens according to claim 1, characterized in that: The air gap between the first positive meniscus lens (31) and the first biconvex lens (71) is 0.37 mm-0.63 mm.

6. The optical lens of the large dynamic star sensor according to claim 1, characterized in that: The air gap between the first biconcave lens (61) and the second biconvex lens (72) is 5.6 mm-11.2 mm; the air gap between the second biconvex lens (72) and the second positive meniscus lens (32) is 6.2 mm-11.8 mm; the air gap between the second positive meniscus lens (32) and the first negative meniscus lens (41) is 1.8 mm-2.6 mm; the air gap between the first negative meniscus lens (41) and the second biconcave lens (62) is 0.8 mm-1.2 mm; and the air gap between the second biconcave lens (62) and the first filter (51) is 1.8 mm-2.6 mm.

7. The optical lens of the large dynamic star sensor according to claim 1, characterized in that: The first positive meniscus lens (31) and the first biconvex lens (71) are both spherical lenses.

8. The large dynamic star sensor optical lens according to claim 1, characterized in that: The first biconcave lens (61), the second biconvex lens (72), the second positive meniscus lens (32), the first negative meniscus lens (41), the second biconcave lens (62) and the first filter (51) are all spherical lenses.

9. The optical lens of a large dynamic star sensor according to claim 1, characterized in that: The optical transfer function of the optical lens is greater than 0.4 when the half field of view is 7° and the spatial frequency is 100lp / mm.

10. The optical lens of a large dynamic star sensor according to claim 1, characterized in that: The relative distortion value of the optical lens is less than 0.05% under a half field of view of 7°.

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