阅读说明：本技术 一种长焦距大视场小型化主动消热差的光学系统 (Long-focus large-view-field miniaturized active athermal optical system ) 是由 武春风 王晓丹 吴丰阳 江颖 董理治 王勋 马社 于 2021-09-17 设计创作，主要内容包括：本发明公开了一种长焦距大视场小型化主动消热差的光学系统,包括卡塞格林反射主镜、反射次镜、场镜、准直镜、第一折叠镜、第二折叠镜、第一成像镜组、第三折叠镜、第二成像镜组、第四折叠镜、成像透镜和探测器焦平面；卡塞格林反射主镜与反射次镜组成卡塞成像系统,在所述卡塞格林反射主镜与反射次镜之间设有所述场镜,所述场镜用于压缩准直镜的视场角和校正成像系统的场曲；所述准直镜、第一折叠镜、第二折叠镜、第一成像镜组、第三折叠镜、第二成像镜组、第四折叠镜、成像透镜和探测器焦平面依次光路连接。本发明能够在较宽的温度范围工作,减小系统的成本,同时利用转折镜优化了系统的空间结构,实现小型化等。(The invention discloses a miniaturized active athermal optical system with a long focal length and a large visual field, which comprises a Cassegrain reflecting primary mirror, a secondary reflecting mirror, a field lens, a collimating mirror, a first folding mirror, a second folding mirror, a first imaging lens group, a third folding mirror, a second imaging lens group, a fourth folding mirror, an imaging lens and a detector focal plane, wherein the Cassegrain reflecting primary mirror is used for reflecting heat; the Cassegrain primary reflector and the secondary reflector form a Cassegrain imaging system, and the field lens is arranged between the Cassegrain primary reflector and the secondary reflector and used for compressing the field angle of the collimating lens and correcting the field curvature of the imaging system; the collimating lens, the first folding lens, the second folding lens, the first imaging lens group, the third folding lens, the second imaging lens group, the fourth folding lens, the imaging lens and the focal plane of the detector are sequentially connected through a light path. The invention can work in a wider temperature range, reduces the cost of the system, simultaneously optimizes the space structure of the system by utilizing the turning mirror, realizes miniaturization and the like.)

1. A miniaturized active athermal optical system with a long focal length and a large view field is characterized by comprising a Cassegrain reflecting primary mirror (1), a secondary reflecting mirror (2), a field lens (3), a collimating mirror (4), a first folding mirror (5), a second folding mirror (6), a first imaging mirror group (7), a third folding mirror (8), a second imaging mirror group (9), a fourth folding mirror (10), an imaging lens (11) and a detector focal plane (12); the Cassegrain primary reflector (1) and the secondary reflector (2) form a Cassegrain imaging system, the field lens (3) is arranged between the Cassegrain primary reflector (1) and the secondary reflector (2), and the field lens (3) is used for compressing the field angle of the collimating lens (4) and correcting the field curvature of the imaging system; the collimating lens (4), the first folding lens (5), the second folding lens (6), the first imaging lens group (7), the third folding lens (8), the second imaging lens group (9), the fourth folding lens (10), the imaging lens (11) and the detector focal plane (12) are sequentially connected through an optical path.

2. The long-focal-length large-field-of-view miniaturized active athermal optical system according to claim 1, wherein said field lens (3) is a negative lens of the meniscus type.

3. The optical system for active athermalization with long focal length and large field of view miniaturization according to claim 1, wherein said Cassegrain reflector primary mirror (1) is an aspherical mirror, and reflective imaging is adopted.

4. The long-focal-length large-visual-field miniaturized active athermal optical system according to claim 1, wherein the first folding mirror (5), the second folding mirror (6), the first imaging mirror group (7), the third folding mirror (8), the second imaging mirror group (9), the fourth folding mirror (10), the imaging lens (11) and the detector focal plane (12) are all spherical mirrors.

5. The optical system for active thermal difference elimination with long focal length and large visual field miniaturization as claimed in claim 1, is characterized in that a coarse tracking system for laser orientation energy equipment is matched with a 10-time optical zoom system, the focal length of the optical system is 100mm to 1000mm, and the optical system can image and track a target with 20 Km.

6. The optical system for active athermalization with long focal length and large field of view miniaturization according to claim 1, wherein said secondary mirror (2) is an aspherical mirror, employing reflective imaging.

Technical Field

The invention relates to the technical field of photoelectric tracking and aiming imaging, in particular to a miniaturized active athermal optical system with a long focal length and a large view field.

Background

The light beam control and tracking aiming equipment (ATP for short) is an important component of laser directional energy weapons and multifunctional laser combat vehicles, and aims to realize the tracking of a target through a photoelectric imaging probe and then realize the multi-stage stable imaging tracking of the target through the precise tracking imaging of the tracked target. The prior art has the following defects: short focal length, small field of view, large volume and serious heat difference.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a miniaturized optical system with a long focal length and a large visual field for actively eliminating thermal difference, can work in a wider temperature range, not only utilizes the function of blocking the long focal length, but also utilizes a field lens to compress the visual field angle to reduce the size of an optical imaging lens and reduce the cost of the system, and simultaneously utilizes a turning lens to optimize the space structure of the system and realize miniaturization and the like.

The purpose of the invention is realized by the following scheme:

a miniaturized active athermal optical system with long focal length and large view field comprises a Cassegrain reflecting primary mirror, a secondary reflecting mirror, a field lens, a collimating mirror, a first folding mirror, a second folding mirror, a first imaging lens group, a third folding mirror, a second imaging lens group, a fourth folding mirror, an imaging lens and a detector focal plane; the Cassegrain primary reflector and the secondary reflector form a Cassegrain imaging system, the field lens is arranged between the Cassegrain primary reflector and the secondary reflector, and the field lens is used for compressing the field angle of the collimating lens and correcting the field curvature of the imaging system; the collimating lens, the first folding lens, the second folding lens, the first imaging lens group, the third folding lens, the second imaging lens group, the fourth folding lens, the imaging lens and the focal plane of the detector are sequentially connected through a light path.

Further, the field lens is a negative lens of a meniscus type.

Furthermore, the Cassegrain reflecting main mirror is an aspheric mirror and adopts a reflective imaging mode.

Furthermore, the focal planes of the first folding mirror, the second folding mirror, the first imaging lens group, the third folding mirror, the second imaging lens group, the fourth folding mirror, the imaging lens and the detector are all spherical mirrors.

Further, a coarse tracking system equipped for laser orientation can be matched with a 10-time optical zoom system, the focal length of the optical system is 100mm to 1000mm, and the target with the depth of 20Km can be imaged and tracked.

Furthermore, the secondary reflection mirror is an aspheric mirror and adopts reflective imaging.

The beneficial effects of the invention include:

the optical system provided by the embodiment of the invention has the entrance pupil aperture of 250mm, the focal length of 1400mm and the field of view of 7.2mrad multiplied by 7.2mrad, can work in a wider temperature range, has high optical system resolution and can detect an object at an ultra-far distance.

The embodiment of the invention can realize wide temperature range work.

The embodiment of the invention not only utilizes the function of blocking a long focal length, but also utilizes the field lens to compress the field angle to reduce the size of the optical imaging lens, thereby reducing the cost of the system, and also utilizes the turning lens to optimize the space structure of the system and realize miniaturization.

The system is compact, low in cost and easy to realize.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a general view of an optical system of the present invention;

FIG. 2 is an expanded view of the optical imaging of the present invention;

FIG. 3 is a folded view of the optical imaging of the present invention;

FIG. 4 is a beam tracking system housing embodying the present invention;

FIG. 5 is a dot-plot of a-30 ℃ optical system of the present invention;

FIG. 6 is a plot of the MTF of the-30 ℃ optical system of the present invention;

FIG. 7 is a dot-line diagram of a 20 ℃ optical system of the present invention;

FIG. 8 is a 20 ℃ optical system MTF plot of the present invention;

FIG. 9 is a dot-line diagram of a 50 ℃ optical system of the present invention;

FIG. 10 is a graph of the MTF of a 50 ℃ optical system of the present invention;

table 1 is a data diagram of an optical system embodying the present invention;

in the figure, 1-Cassegrain reflector primary mirror; 2-secondary mirror; 3-a field lens; 4-a collimating mirror; 5-a first fold mirror; 6-a second fold mirror; 7-a first imaging lens group; 8-a third fold mirror; 9-a second imaging mirror group; 10-a fourth fold mirror; 11-an imaging lens; 12 detector focal plane; a-coarse tracking optics.

Detailed Description

All features disclosed in all embodiments in this specification, or all methods or process steps implicitly disclosed, may be combined and/or expanded, or substituted, in any way, except for mutually exclusive features and/or steps.

As shown in fig. 1 to 10, an optical system with a long focal length and a large field of view for miniaturization and active thermal difference elimination comprises a cassegrain primary reflector 1, a secondary reflector 2, a field lens 3, a collimating lens 4, a first folding lens 5, a second folding lens 6, a first imaging lens group 7, a third folding lens 8, a second imaging lens group 9, a fourth folding lens 10, an imaging lens 11 and a detector focal plane 12; the Cassegrain primary reflector 1 and the secondary reflector 2 form a Cassegrain imaging system, a field lens 3 is arranged between the Cassegrain primary reflector 1 and the secondary reflector 2, and the field lens 3 is used for compressing the field angle of the collimating lens 4 and correcting the field curvature of the imaging system; the collimating lens 4, the first folding lens 5, the second folding lens 6, the first imaging lens group 7, the third folding lens 8, the second imaging lens group 9, the fourth folding lens 10, the imaging lens 11 and the detector focal plane 12 are connected in sequence through light paths.

In an alternative embodiment, the field lens 3 is a negative lens of the meniscus type.

In an alternative embodiment, the cassegrain primary mirror 1 is an aspherical mirror, employing reflective imaging.

In an alternative embodiment, the first folding mirror 5, the second folding mirror 6, the first imaging mirror group 7, the third folding mirror 8, the second imaging mirror group 9, the fourth folding mirror 10, the imaging lens 11 and the detector focal plane 12 are all spherical mirrors.

In an alternative embodiment, the coarse tracking system equipped for laser orientation can be matched with a 10-time optical zoom system, and the focal length of the optical system is 100mm to 1000mm, so that a target with the depth of 20Km can be imaged and tracked.

In an alternative embodiment, secondary mirror 2 is an aspherical mirror, and reflective imaging is used.

The invention relates to a miniaturized active athermal optical system with a long focal length and a large visual field, which consists of a Cassegrain system, a field lens, a collimation system, a turning lens and an imaging system.

The specific working principle of the invention is as follows:

the optical system of an embodiment of the present invention may be used in a beam tracking control system, as shown in fig. 4. The photoelectric tracking rotary table is used for realizing the long-distance imaging stable primary tracking of the target, and a 10-time primary tracking visible light and near infrared coarse tracking system is matched, so that the focal length is 100mm to 1000mm, and the detection distance of 20Km for small targets and other large targets can be realized.

The embodiment of the invention realizes a miniaturized imaging optical system with a long focal length and a large visual field by utilizing a Cassegrain system, a field lens, a collimation system, a turning lens and an imaging system. The Cassegrain system is a primary mirror and a secondary mirror, the obscuration ratio is one tenth, and the primary mirror and the secondary mirror are both of a reflection type structure. The field lens is used for eliminating field curvature and astigmatism of the system, reducing the field angle of an image and eliminating partial vignetting. The collimation system is used for balancing aberration of the system, reducing the size of the imaging system, and secondary imaging is carried out on the collimation system and the imaging system after primary imaging of the blocking system. The detector of the embodiment of the invention is a conventional detector, the resolution ratio is 2000mm multiplied by 2000mm, and the pixel size is 5.5 um. Table 1 shows a material diagram of the optical system, and the parameters related to the material, thickness, curvature, and the like of the optical system can be known from table 1.

TABLE 1 optical parameters of optical systems

Serial number	Material	Radius of curvature/mm	Thickness/mm
				1	Mirror	-290.22	-120.00
2	Mirror	-84.07	60.00
				3	ZNS	-10.57	25.00
4		-19.75	58.00
				5	CAF	-75.92	3.00
6		40.78	0.20
				7	BAF	26.92	7.63
8		-43.54	72.00
				9	IGN102	28.61	7.08
10		72.86	3.00
				11	SF3	88.75	5.00
12		26.69	9.45
				13	SK16	-20.93	5.00
14		-36.13	3.00
				16	H-ZF52	-58.36	3.50
17		-36.04	50.00
				18	IRGN6	-25.06	5.63
19		-28.60	2.34
				20	H-ZK21	556.07	8.00
21		-164.34	15.00
				22	H-ZK72A	36.88	8.00
23		31.29	70.00
				24	LF5HTI	53.34	0.00
25		-19678.36	8.00

Fig. 2 and 3 are structural diagrams of a system according to an embodiment of the present invention, fig. 2 is an expanded view of the system according to the embodiment of the present invention, and fig. 3 is a folded view of the system according to the embodiment of the present invention, and the space of the optical system can be optimized by the turning mirror, so that the structure of the system can be miniaturized and engineered.

From fig. 4 to fig. 10, the spot alignment chart and the MTF curve chart of the optical system under different stabilities are shown, and the spot alignment chart and the MTF curve of the optical system are well controlled at-30 ℃ and +50 ℃.

Other parameters of the optical system are that an aperture diaphragm is arranged on a primary mirror, the focal length of the system is 1400mm, the F number is 7, the wave band is 0.4um to 0.86um, and the spatial resolution is 1.76 ruad.

In fig. 4, a denotes a rough tracking optical system.

The imaging quality of the optical system is different at different temperatures, the thermal defocusing is set as a criterion of primary aberration, the system adopts aluminum in structure, and in the imaging system, a material with a small refractive index variation with temperature and a material with a large abbe number and a material with a large refractive index variation with temperature are selected to mutually correct the thermal defocusing and the chromatic aberration of the system.

The parts not involved in the present invention are the same as or can be implemented using the prior art.

The above-described embodiment is only one embodiment of the present invention, and it will be apparent to those skilled in the art that various modifications and variations can be easily made based on the application and principle of the present invention disclosed in the present application, and the present invention is not limited to the method described in the above-described embodiment of the present invention, so that the above-described embodiment is only preferred, and not restrictive.

Other embodiments than the above examples may be devised by those skilled in the art based on the foregoing disclosure, or by adapting and using knowledge or techniques of the relevant art, and features of various embodiments may be interchanged or substituted and such modifications and variations that may be made by those skilled in the art without departing from the spirit and scope of the present invention are intended to be within the scope of the following claims.