阅读说明：本技术 一种具有卡式焦点的大视场紧凑型折反式望远镜光学系统 (Large-view-field compact catadioptric telescope optical system with clamping type focus ) 是由 李正阳 袁祥岩 李博 于 2021-09-07 设计创作，主要内容包括：本发明公开了一种具有卡式焦点的大视场紧凑型折反式望远镜光学系统,包括球差校正透镜组、中心开孔的球面主镜、球面副镜、视场像差校正透镜组、卡式焦点位置的焦平面；其中,所述球差校正透镜组位于系统入瞳位置,且其靠近球面主镜的透镜凸面中心区域镀反射膜、边缘环带镀增透膜,该区域为球面副镜位置,球差校正透镜组与球面副镜共用一块光学元件；所述视场像差校正透镜组位于球面主镜的背面、焦平面之前；所述光学系统的焦平面位于卡式焦点处。该光学系统同时兼具小体积、快焦比、大视场、宽波段、终端探测器安装维护便利的特点,可大幅提高望远镜的观测能力和探测效率。(The invention discloses a large-view-field compact catadioptric telescope optical system with a clip-type focus, which comprises a spherical aberration correction lens group, a spherical primary mirror with a central hole, a spherical secondary mirror, a view field aberration correction lens group and a focal plane at a clip-type focus position, wherein the spherical primary mirror is provided with a central hole; the spherical aberration correcting lens group is positioned at the position of the entrance pupil of the system, the central area of the convex surface of the lens, which is close to the spherical primary mirror, is plated with a reflecting film, the peripheral girdle band is plated with an antireflection film, the area is the position of the spherical secondary mirror, and the spherical aberration correcting lens group and the spherical secondary mirror share one optical element; the field aberration correction lens group is positioned on the back of the spherical main mirror and in front of a focal plane; the focal plane of the optical system is located at the bayonet focus. The optical system has the characteristics of small volume, fast focal ratio, large visual field, wide wave band and convenience in installation and maintenance of the terminal detector, and can greatly improve the observation capability and detection efficiency of the telescope.)

1. A large-view-field compact catadioptric telescope optical system with a cassette focus is characterized in that: comprises a spherical aberration correction lens group, a spherical primary mirror (3) with a hole at the center, a spherical secondary mirror (4), a field aberration correction lens group and a focal plane (7) at a clip-type focal position; the spherical aberration correction lens group is positioned at the position of the entrance pupil of the system, the central area of the convex surface of the lens, which is close to the spherical primary mirror, is plated with a reflecting film, the peripheral girdle band is plated with an antireflection film, the area is the position of the spherical secondary mirror (4), and the spherical aberration correction lens group and the spherical secondary mirror (4) share one optical element; the field aberration correction lens group is positioned on the back surface of the spherical main mirror (3) and in front of the focal plane (7); the focal plane (7) of the optical system is located at the bayonet focus.

2. The optical system of claim 1, wherein the optical system comprises a large field of view compact catadioptric telescope with a bayonet focus, and further comprising: on-axis aberrations and off-axis field aberrations in the optical system can be corrected independently, with the optical power being concentrated on the reflective optical element.

3. The optical system of claim 1, wherein the optical system comprises a large field of view compact catadioptric telescope with a bayonet focus, and further comprising: the imaging wave band range of the optical system is 0.4-1 μm.

4. The optical system of claim 1, wherein the optical system comprises a large field of view compact catadioptric telescope with a bayonet focus, and further comprising: the optical elements in the optical system are global surface elements.

5. The optical system of claim 4, wherein the optical system comprises a large field of view compact catadioptric telescope with a bayonet focus, and further comprising: the spherical aberration correction lens group comprises a first spherical aberration correction meniscus lens (1) and a second spherical aberration correction meniscus lens (2), wherein a reflection film is plated in a central convex surface area of the second spherical aberration correction meniscus lens (2), an antireflection film is plated in an edge annular belt, the second spherical aberration correction meniscus lens (2) and a spherical auxiliary lens (4) share one optical element, and the distance from the second spherical aberration correction meniscus lens (2) to the spherical main lens (3) is equal to the distance from the second spherical aberration correction meniscus lens (2) to the spherical main lens (3) at the interval between the spherical main lens (3) and the spherical auxiliary lens (4).

6. The optical system of claim 5, wherein the optical system comprises: the air interval between the first spherical aberration correction meniscus lens (1) and the second spherical aberration correction meniscus lens (2) is 17mm, and the air interval between the second spherical aberration correction meniscus lens (2) and the spherical main mirror (3) is 275.5 mm.

7. The optical system of claim 6, wherein the optical system comprises: the field aberration correction lens group comprises a first field aberration correction lens (5) and a second field aberration correction lens (6), the distance from the spherical secondary mirror (4) to the first field aberration correction lens (5) is 350.5mm, and the distance from the first field aberration correction lens (5) to the second field aberration correction lens (6) is 2 mm.

8. The optical system of claim 7, wherein the optical system comprises: the distance from the second field aberration correction lens (6) to the focal plane is 70 mm.

Technical Field

The invention relates to an optical system in the field of space detection, in particular to a large-view-field compact catadioptric telescope optical system with a cassette focus.

Background

The space astronomical telescope is a type of space optical load which is carried on a satellite platform and used for imaging and measuring a universe celestial body. In order to acquire a star image with high resolution, a ground-based telescope gradually develops towards a large-caliber large-field-of-view direction. However, if the satellite system is built and started in the outer space, the mass and the volume of the satellite system are overlarge due to the fact that the space telescope is large in size, the difficulty in carrying the telescope in the outer space is increased, and the satellite launching cost is increased to a great extent. Therefore, a light-weight space telescope with a small size, high flexibility and high resolution in a new structural form has become a research hotspot in the field.

The CSTAR telescope is firstly developed and successfully developed by Nanjing astronomical optical technology research institute of Chinese academy of sciences, is installed on the highest point ice fornix A of the south Pole inland in 2008 and is used for astronomical observation. The invention takes the deformation structure of the optical system as a prototype, optimizes the optical elements on the premise of ensuring excellent image quality, shortens the distance between spherical aberration correction lenses, enlarges the clear aperture to increase the light collecting capacity, and lengthens the rear intercept to install a large image plane detector, so that the large image plane detector can better meet the use requirement of space detection.

Disclosure of Invention

In view of the above problems in the prior art, the present invention provides a compact catadioptric telescope optical system with a large field of view and a bayonet focus.

In order to achieve the purpose, the invention provides the following technical scheme:

a large-view-field compact catadioptric telescope optical system with a clip-type focus comprises a spherical aberration correction lens group, a spherical primary mirror with a hole at the center, a spherical secondary mirror, a view field aberration correction lens group and a focal plane at a clip-type focus position; the spherical aberration correcting lens group is positioned at the position of the entrance pupil of the system, the central area of the convex surface of the lens, which is close to the spherical primary mirror, is plated with a reflecting film, the peripheral girdle band is plated with an antireflection film, the area is the position of the spherical secondary mirror, and the spherical aberration correcting lens group and the spherical secondary mirror share one optical element; the field aberration correction lens group is positioned on the back of the spherical main mirror and in front of a focal plane; the focal plane of the optical system is located at the bayonet focus.

Further, on-axis aberrations and off-axis field aberrations in the optical system can be corrected independently, with the power being concentrated on the reflective optical element.

Further, the imaging wave band range of the optical system is 0.4-1 μm.

Further, the optical element in the optical system is a global surface element.

Furthermore, the spherical aberration correction lens group comprises a first spherical aberration correction meniscus lens and a second spherical aberration correction meniscus lens, a reflecting film is plated in a central convex surface area of the second spherical aberration correction meniscus lens, an antireflection film is plated in an edge annular belt, the second spherical aberration correction meniscus lens and the spherical auxiliary lens share one optical element, and the distance between the spherical main lens and the spherical auxiliary lens is equal to the distance between the second spherical aberration correction meniscus lens and the spherical main lens.

Further, an air space between the first spherical aberration correction meniscus lens and the second spherical aberration correction meniscus lens is 17mm, and an air space between the second spherical aberration correction meniscus lens and the spherical primary mirror is 275.5 mm.

Further, the field aberration correction lens group comprises a first field aberration correction lens and a second field aberration correction lens, the distance from the spherical secondary mirror to the first field aberration correction lens is 350.5mm, and the distance from the first field aberration correction lens to the second field aberration correction lens is 2 mm.

Further, the distance from the second field aberration correction lens to the focal plane is 70 mm.

Compared with the prior art, the invention has the following beneficial effects:

the large-view-field compact catadioptric telescope optical system with the cassette focus adopts a catadioptric optical framework to obtain the cassette focus which is convenient to use, and a terminal detector is convenient to install and maintain; the large-size spherical aberration correction lens group is arranged at the position of the system diaphragm, the auxiliary lens of the optical system is replaced while the system aberration is corrected, and the small-size field correction lens is arranged at the position close to the focal plane, so that the large-size spherical aberration correction lens group has the advantages of short length, small volume and light weight, meets the light-weight requirement of a space telescope, and saves the design cost of the system. Meanwhile, the device has the characteristics of fast focal ratio, large field of view, wide band and convenience in installation and maintenance of the terminal detector, and the observation capability and detection efficiency of the telescope are greatly improved.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.

Drawings

FIG. 1 is a diagram of an optical system according to an embodiment of the present invention.

Fig. 2 is an implementation schematic diagram of the optical system architecture of fig. 1.

Fig. 3 is a picture (stippled chart) showing the image quality of the optical system under the full field of view.

FIG. 4 is a pictorial representation of an embodiment of the present invention; wherein (a) is a front view; (b) is a side view.

The labels in the figure are: 1. a first spherical aberration correcting meniscus lens; 2. a second spherical aberration correcting meniscus lens; 3. the spherical primary mirror is provided with a hole at the center; 4. a spherical secondary mirror; 5. a first field aberration correcting lens; 6. a second field aberration correction lens; 7. a focal plane.

Detailed Description

The invention relates to a large-view-field compact catadioptric telescope optical system with a clamping type focus, which comprises a spherical aberration correction lens group, a spherical primary mirror 3 with a hole at the center, a spherical secondary mirror 4, a view field aberration correction lens group and a focal plane 7 at the position of the clamping type focus. The spherical aberration correcting lens group is positioned at the position of the entrance pupil of the system, the central area of the convex surface of the lens, which is close to the spherical primary mirror, is plated with a reflecting film, the peripheral girdle band is plated with an antireflection film, the area is the position of the spherical secondary mirror 4, and the spherical aberration correcting lens group and the spherical secondary mirror 4 share one optical element; the field aberration correction lens group is positioned on the back of the spherical main mirror 3 and in front of the focal plane 7; the focal plane of the optical system is located at the cassette focus. By virtue of the independent correction of the on-axis aberration and the off-axis field aberration of the optical system, and the focal power is concentrated on the reflective optical element, the optical system can obtain broadband (0.4-1 μm waveband) imaging and has uniform and good full-field image quality on the flat image plane. The invention adopts the refraction-reflection type optical architecture to obtain the convenient-to-use card type focus, and the terminal detector is convenient to install and maintain; the large-size spherical aberration correction lens group is arranged at the position of the system diaphragm, the auxiliary lens of the optical system is replaced while the system aberration is corrected, and the small-size field correction lens group is arranged at the position close to the focal plane, so that the large-size spherical aberration correction lens group has the advantages of short length, small volume and light weight, meets the light-weight requirement of a space telescope, and saves the design cost of the system. Meanwhile, the device has the characteristics of fast focal ratio, large field of view, wide band and convenience in installation and maintenance of the terminal detector, and the observation capability and detection efficiency of the telescope are greatly improved.

As shown in fig. 1 and 4, the spherical aberration correction lens group in the present embodiment is preferably composed of two positive meniscus lenses (i.e., a first spherical aberration correction meniscus lens 1 and a second spherical aberration correction meniscus lens 2), and the field aberration correction lens group in the present embodiment is preferably composed of two positive lenses (i.e., a first field aberration correction lens 5 and a second field aberration correction lens 6). The large-field compact catadioptric telescope optical system with a bayonet focus shown in the embodiment of fig. 1 specifically comprises a first spherical aberration correction meniscus lens 1, a second spherical aberration correction meniscus lens 2, a spherical primary lens 3 with a central hole, a spherical secondary lens 4 (a central convex surface of the lens 2), a first field aberration correction lens 5, a second field aberration correction lens 6 and a focal plane 7 at the position of the bayonet focus. The principle of implementation of this optical system is shown in fig. 2. The optical element in the optical system of the embodiment is a global surface element; the first spherical aberration correction meniscus lens 1 and the second spherical aberration correction meniscus lens 2 are positioned at the system entrance pupil position; the second spherical aberration correction meniscus lens 2 and the spherical secondary lens 4 share one optical element, the central area of the second spherical aberration correction meniscus lens 2 is plated with a reflecting film, and the edge ring belt is plated with an antireflection film; the first field aberration correction lens 5 and the second field aberration correction lens 6 are positioned behind the spherical primary mirror 3 and in front of the focal plane 7; the system focal plane 7 is located at the bayonet focus.

Preferably, in the present embodiment, the air space between the first spherical aberration correcting meniscus lens 1 and the second spherical aberration correcting meniscus lens 2 is 17mm, the air space between the second spherical aberration correcting meniscus lens 2 and the spherical primary mirror 3 is 275.5mm, the space between the spherical primary mirror 3 and the spherical secondary mirror 4 is equal to the distance from the second spherical aberration correcting meniscus lens 2 to the spherical primary mirror 3, the distance from the spherical secondary mirror 4 to the first field aberration correcting lens 5 is 350.5mm, the distance from the first field aberration correcting lens 5 to the second field aberration correcting lens 6 is 2mm, and the distance from the second field aberration correcting lens 6 to the focal plane 7 is 70 mm.

The optical system composed of the lens achieves the following optical indexes:

1. focal length: f is 900 mm;

2. relative pore diameter: 1/3;

3. the field angle: 2 w-4.6 °;

4. designing a wave band: 0.400-1 μm;

5. field spot RMS (field angle 4.6 °): 80% of energy of the full-field point diagram is concentrated in a circular area with the radius of 10.2 mu m, and the RMS radius of the full-field point diagram is less than or equal to 7.5 mu m (shown in a figure 2 in detail);

6. total length of lens barrel: less than or equal to 450 mm.

The image quality point chart of the optical system in the full field of view of the present embodiment is shown in fig. 3. The optical system of this embodiment uses 2 spherical aberration correcting lenses, 2 field aberration correcting lenses, and 2 mirrors (wherein the secondary mirror is shared), to achieve good optical image quality. In the optimization design, the operation number and the weight are reasonably selected, so that various aberrations are effectively controlled. Considering the processing difficulty of the large-aperture lens, relaxing the processing requirement of the vertex curvature radius of the spherical aberration correction lens, and after obtaining the actual measurement value, adjusting the vertex curvature radius compensation of the field-of-view correction lens to obtain the embodiment close to the design value.

The diameter of the entrance pupil of the lens is 300mm, and the focal ratio of the system is f/3. Under the conditions of meeting the light energy and ensuring the image quality, the light-transmitting optical fiber has the advantages of light, small and compact structure, short length, small volume and light weight, and has the characteristics of large view field and wide band. Due to its fast f/3 focal ratio and corrected 80mm wide field of view, the system has no vignetting in the 4.6 ° field of view and excellent image quality. The telescope can meet the requirements of astronomical photography, astronomical sky patrol, space debris observation and the like.

In conclusion, the invention is a telescope optical system which obtains a fast focal ratio of a cassette focus and has large visual field and good imaging quality; the spherical aberration correcting lens and the spherical auxiliary lens share the convex surface of the lens by plating the reflecting film on the central area of the large-size spherical aberration correcting lens and plating the antireflection film on the edge girdle band, so that the light path is light and flexible, the volume is small, the weight is light, and the design, processing and detection cost is saved; in the embodiment, the field aberration is corrected by adopting a mode of two field aberration correction lenses, and when the field is enlarged, the field aberration correction lenses can be increased to 3 or 4.

The above description is only an example of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.