CN111323896A - Rear-group focusing large-field-of-view long rear-intercept zooming system and optical zoom lens - Google Patents

Abstract

The invention discloses a large-field-of-view long rear-intercept zooming system with rear group focusing and an optical zoom lens, which comprise a first lens group, a second lens group, a third lens group, a diaphragm device, a fourth lens group and a full target surface; the first lens group, the third lens group and the fourth lens group all have positive focal power, the second lens group has negative focal power, and the fourth lens group comprises a focusing group with positive focal power; changing the interval of each lens group by moving the second lens group and the third lens group for zooming; and correcting the position change of the image plane under different object distances by moving the focusing group. The invention carries on the zooming by changing the interval of each lens group; correcting image plane position variation by moving the focusing group; the focusing group can realize the focusing of the zoom system by selecting a single lens, so that focusing structural members and driving structures are reduced, the cost of the system is greatly reduced, and the practicability is high; the two variable-focal-length lens groups move according to a certain mode to realize the processes of miniaturization, large visual field and long rear intercept zooming.

Description

Rear-group focusing large-field-of-view long rear-intercept zooming system and optical zoom lens

Technical Field

The invention relates to the technical field of monitoring devices, in particular to a rear group focusing large-field-of-view long-rear-intercept zooming system and an optical zoom lens.

Background

Imaging systems have found wide application in both military and civilian applications. In some imaging systems, such as a reconnaissance system and a ground remote sensing system, in order to complete target capture and tracking, a zoom system needs to be integrated in the system to obtain clear images of targets at different object distances and different fields of view; the zoom system can not lose the tracked target in the zooming process, and can select a view field with a proper size according to the target characteristics, thereby greatly improving the tracking and monitoring effects.

The traditional zoom system only consists of one or more fixed focal length lens groups and one or more variable focal length lens groups, and the focal length of the system is changed by moving the variable focal length lens groups in a lens barrel or fixing the variable focal length lens groups in a telescopic movable lens barrel by utilizing a mechanical device such as a space cam and the like. Both of these methods change the focal length of the system by changing the optical structure within the system. The traditional focusing structure in the zoom system is generally realized by moving the front fixed focal length lens group, the caliber and the weight of the front fixed focal length lens group are relatively large, the whole length can be correspondingly changed, certain problems can exist during application, and certain limitations can exist in the view field and the rear intercept.

With the development of monitoring markets, the universality of large target surfaces of detectors, F bayonet interfaces and the like, parameters such as large view field, long rear intercept and the like are required, so that a rear-group focused large view field long rear intercept zoom system is urgently needed.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: a zoom system is provided that has a large field of view, a long back intercept, and has a back group focus.

In order to solve the technical problems, the invention is realized by the following technical scheme: a large-view-field long-rear-intercept zooming system with rear group focusing comprises a first lens group, a second lens group, a third lens group, a diaphragm, a fourth lens group and a full target surface which are sequentially arranged from left to right and are positioned in the same optical axis direction; wherein the content of the first and second substances,

the first lens group, the third lens group and the fourth lens group all have positive focal power, the second lens group has negative focal power, and the fourth lens group comprises a focusing group with positive focal power;

the first lens group and the fourth lens group are fixed focal length lens groups, and the second lens group and the third lens group are variable focal length lens groups capable of moving along the optical axis direction; changing the interval of each lens group by moving the second lens group and the third lens group to perform zooming between a wide-angle end and a telephoto end of the zoom system; and correcting the position change of the image plane under the condition of different object distances by moving the focusing group.

Further, the first lens group comprises a first cemented lens and a first single lens which correspond to each other, wherein the first cemented lens is a concave lens made of ZF4_ CHINA material, the second cemented lens is a convex lens made of HQK3_ CDGM material, and the first single lens is a convex lens made of ZK series material.

Further, the second lens group comprises a second single lens and a second cemented lens which correspond to each other, wherein the second single lens is a concave lens made of a material selected from HZK21_ CDGM, the first lens of the second cemented lens is a concave lens made of a material selected from HZK3_ CDGM, and the second lens is a convex-concave lens made of a material selected from high-refractive-index and low-dispersion materials.

Further, the third lens group comprises a third single lens and a third cemented lens which correspond to each other, wherein the third single lens is a convex lens made of LAF material, the first lens of the third cemented lens is a convex lens made of HZBAF3_ CDGM material, and the second lens is a concave lens made of ZF4_ CHINA material.

Further, the fourth lens group further includes a fourth single lens, a fifth single lens and a fourth cemented lens, which correspond to each other, wherein the fourth single lens is a concave lens made of LAK material, the focusing group is a meniscus lens made of HQK3L _ CDGM material, the fifth single lens is a convex lens made of HQK3L _ CDGM material, the first lens of the fourth cemented lens is a convex lens made of HQK3L _ CDGM material, and the second lens is a concave lens made of HZF6_ CDGM material.

Furthermore, the focusing group is a single lens made of HQK3L materials, the focal length is 80 mm-85 mm, the distance between one surface close to the fourth single lens and the fourth single lens is 8.2 mm-10.2 mm, and the distance between one surface close to the fifth single lens and the fifth single lens is 11.2 mm-13.2 mm.

Further, the focal length of the zoom system is f, the diameter of the entrance pupil is D, wherein f is 20 mm-150 mm, and D/f is 1/3.2-1/2.6.

Further, the length of the full target surface is 20 mm-25 mm, and the distance from the full target surface to the fourth cemented mirror, namely the back intercept, is more than or equal to 46.5 mm.

Furthermore, the full field angle at the wide-angle end is more than or equal to 60 degrees, and the zoom ratio is more than or equal to 7.5.

The invention also provides an optical zoom lens, which comprises the rear group focused large-view-field long-rear-intercept zoom system, and light beams reflected by the target are imaged on a full target surface through the rear group focused large-view-field long-rear-intercept zoom system.

Compared with the prior art, the invention has the advantages that:

the zoom system and the optical zoom lens provided by the invention change the interval of each lens group so as to change the magnification between the wide-angle end and the telephoto end; correcting the position change of an image plane under the condition of different object distances by moving the focusing group; the focusing group can realize the focusing of the zoom system by selecting a single lens, so that focusing structural members and driving structures are reduced, the cost of the system is greatly reduced, and the practicability is high; the lenses in the zoom system are made of conventional glass materials, the two variable-focus lens groups move in a certain mode under the condition of less lens number, so that the process of miniaturization, large view field and long rear intercept zooming is realized, the imaging performance is improved, and the zoom lens system has the advantages of simple structure, easiness in assembly, high transmittance and the like, is suitable for mass production, and has wide market prospect.

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, 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 the structures shown in the drawings without creative efforts.

The invention is further described below with reference to the accompanying drawings:

fig. 1 is an overall structural view of a zoom system according to the present invention;

FIG. 2 is a detail block diagram of FIG. 1;

FIG. 3 is a surface profile of each lens in the zoom system;

fig. 4 is an optical system diagram of the zoom system at a focal length f of 20 mm;

fig. 5 is an optical system diagram of the zoom system at a focal length f of 70 mm;

fig. 6 is an optical system diagram of the zoom system at a focal length f of 150 mm;

FIG. 7 is a cam profile of the zoom system;

fig. 8 is a graph of the optical transfer function of the zoom system at a focal length f of 20 mm;

fig. 9 is a graph of the optical transfer function of the zoom system at a focal length f of 70 mm;

fig. 10 is a graph of the optical transfer function of the zoom system at a focal length f of 150 mm;

fig. 11 is a graph of field curvature and distortion of the zoom system at a focal length f of 20 mm;

fig. 12 is a graph of field curvature and distortion of the zoom system at a focal length f of 70 mm;

fig. 13 is a graph of field curvature and distortion of the zoom system at a focal length f of 150 mm;

1. a first lens group; 2. a second lens group; 3. a third lens group; 4. a fourth lens group; 5. a full target surface; 6. a diaphragm device; 11. a first cemented mirror; 12. a first single lens; 21. a second single lens; 22. a second cemented mirror; 31. a third single lens; 32. a third cemented mirror; 41. a fourth single lens; 42. a focusing group; 43. a fifth single lens; 44. and a fourth cemented mirror.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; the connection can be mechanical connection, electrical connection, physical connection or wireless communication connection; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination of technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

Example one

The large-field-of-view long-rear-intercept zoom system with rear group focusing shown in fig. 1 to 3 comprises a first lens group 1, a second lens group 2, a third lens group 3, a diaphragm 6, a fourth lens group 4 and a full target surface 5 which are arranged from left to right in sequence and are positioned in the same optical axis direction; the first lens group 1, the third lens group 3 and the fourth lens group 4 all have positive focal power, the second lens group 2 has negative focal power, the fourth lens group 4 includes a focusing group 42 having positive focal power, the first lens group 1 and the fourth lens group 4 are fixed focal length lens groups, the second lens group 2 and the third lens group 3 are variable focal length lens groups capable of moving along the optical axis direction, and the second lens group 2 and the third lens group 3 are mounted on mechanical devices such as a space cam in a lens barrel to realize the movement of the second lens group 2 and the third lens group 3 so as to further achieve the purpose of zooming; changing the interval of the lens groups by moving the second lens group 2 and the third lens group 3 so as to change the magnification between the wide-angle end and the telephoto end of the zoom system, wherein the full field angle of the wide-angle end is required to be more than or equal to 60 degrees, and the magnification ratio is required to be more than or equal to 7.5; the focusing group 42 is fixed on a moving structure, the focusing group 42 is moved to correct the position change of the image plane under the condition of different object distances, the moving structure is as simple as possible, and a margin is left for a moving space.

The present embodiment performs magnification variation between the wide-angle end and the telephoto end by varying the intervals of the lens groups; correcting image plane position variation under different object distances by moving the focusing group 42; the focusing group 42 can realize focusing of the zoom system by selecting a single lens, so that focusing structural members and driving structures are reduced, the cost of the embodiment is greatly reduced, and the practicability is high.

In one embodiment, the first lens group 1 includes a first cemented lens 11 and a first single lens 12 corresponding to each other, wherein the first cemented lens 11 has a concave lens made of ZF4 CHINA material, the second cemented lens is a convex lens made of HQK3 CDGM material, the rear surface of the first cemented lens 11 and the front surface of the second cemented lens are coincident, forming surfaces S1, S2 and S3, and the first single lens 12 is a convex lens made of ZK material and having surfaces S4 and S5.

In one embodiment, the second lens group 2 includes a second single lens 21 and a second cemented lens 22 corresponding to each other, wherein the second single lens 21 is a concave lens made of HZK21_ CDGM material and has surfaces S6 and S7, the first lens of the second cemented lens 22 is a concave lens made of HZK3_ CDGM material, the second lens is a convex-concave lens made of high refractive index and low dispersion material, and the rear surface of the first lens of the second cemented lens 22 and the front surface of the second lens are coincident, and then surfaces S8, S9 and S10 are formed.

In one embodiment, the third lens group 3 includes a third single lens 31 and a third cemented lens 32 corresponding to each other, wherein the third single lens 31 is a convex lens made of LAF-based material and has surfaces S11 and S12, the first lens of the third cemented lens 32 is a convex lens made of hzba 3_ CDGM material, the second lens is a concave lens made of ZF4_ CHINA material, the rear surface of the first lens of the third cemented lens 32 and the front surface of the second lens are coincident with each other, thereby forming surfaces S13, S14 and S15, and the stop 6 has a surface S16.

In one embodiment, the fourth lens group 4 further includes a fourth single lens 41, a fifth single lens 43 and a fourth cemented lens 44 corresponding to each other, wherein the fourth single lens 41 is a concave lens made of LAK-based material and has surfaces S17 and S18, the focusing group 42 is a concave-convex lens made of HQK3L _ CDGM material and has surface S19 and surface S20, the fifth single lens 43 is a convex lens made of HQK3L _ CDGM material and has surface S21 and surface S22, the first lens of the fourth cemented lens 44 is a convex lens made of HQK3L _ CDGM material, the second lens is a concave lens made of HZF6_ CDGM material, and the rear surface of the first lens of the fourth cemented lens 44 and the front surface of the second lens coincide to form surfaces S23, S24 and S25, and the full target surface 365 has a surface also called surface S26 and an image plane.

In one embodiment, the focusing assembly 42 is a single lens made of HQK3L material, the focal length is 83mm, the distance from the surface close to the fourth single lens 41 is 9.2mm, the distance from the surface close to the fifth single lens 43 is 12.2mm, the single lens is made of conventional glass material, the focusing structure and the driving structure are reduced, and the cost of the present invention is greatly reduced.

In one embodiment, the focal length of the zoom system is f, the diameter of an entrance pupil is D, wherein f is 20mm to 150mm, and the relative caliber D/f is 1/2.8, which belongs to a lens index and is set conventionally in experiments; the length of the full target surface 5 is 23mm, and the distance from the full target surface 5 to the fourth cemented mirror 44, namely the back intercept is 46.6 mm; when f is 20mm, the wide-angle end full field is 60 °, and when f is 150mm, the wide-angle end full field is 8.8 °.

This embodiment uses only 14 lenses, including 4 cemented lenses: first, second, third, and fourth plywoods 11, 22, 32, 44, 6 single lenses: the first single lens 12, the second single lens 21, the third single lens 31, the fourth single lens 41, the focusing group 42, and the fifth single lens 43 have the characteristics of simple structure, easy assembly, and high transmittance. The two variable-focal-length lens groups move according to a certain mode to realize the processes of miniaturization, large visual field and long rear intercept zooming under the condition of less lens number by selecting conventional glass materials, and simultaneously improve the imaging performance.

The parameters of each lens in the zoom system are shown in table one:

the radius of curvature refers to the radius of curvature of each surface, and the spacing refers to the distance between two adjacent surfaces, for example, the distance between the surfaces S1 is the distance from the surface S1 to the surface S2.

During the zooming process, three change positions are shown in table two:

when the focal length f is 20mm, the optical system diagram is shown in fig. 4; when the focal length f is 70mm, the optical system diagram is shown in fig. 5; when the focal length f is 150mm, the optical system diagram is shown in fig. 6.

Fig. 7 is a cam graph of the present embodiment, in which the abscissa is the cam rotation angle, the ordinate is the movement distance or focal length, and the three curves are the focal length of the zoom optical system, the movement distance of the zoom group, and the movement distance of the compensation group, respectively.

When the focal length f is 20mm, the optical transfer function curve is shown in fig. 8; when the focal length f is 70mm, the optical transfer function curve is shown in fig. 9; when the focal length f is 150mm, the optical transfer function curve is shown in fig. 10, in fig. 8 to 10, the horizontal axis represents the number of line pairs per millimeter, and the vertical axis represents the contrast value.

When the focal length f is 20mm, the field curvature and distortion curve are shown in fig. 11; when the focal length f is 70mm, the field curvature and distortion curve are shown in fig. 12; when the focal length f is 150mm, the field curvature and distortion curve are shown in fig. 13.

The main optical indicators of the present embodiment are: the focal length is 20 mm-150 mm, the field angle is 60-8.8 degrees, and the F number is 2.8.

The specific using process of the rear group focused large-view-field long-rear-intercept zooming system comprises the following steps:

the light beam incident to the first lens group 1 is focused by the first lens group 1, refracted by the second lens group 2, refracted by the third lens group 3, reflected by the fourth lens group 4 and the diaphragm 6 in sequence and then imaged on the full target surface 5 to form an image surface. The relative motion of the zooming group of the second lens group 2 and the compensation group of the third lens group 3 realizes the imaging of the optical system on the full target surface 5 by zooming, and the clear imaging of the optical system can be realized when the distance between the optical system and an object is different by moving the focusing group 42 in the fourth lens group 4.

Example two

Another large-field-of-view long-rear-intercept zoom system with rear group focusing, as shown in fig. 1 to fig. 3, includes a first lens group 1, a second lens group 2, a third lens group 3, a stop 6, a fourth lens group 4 and a full target surface 5, which are arranged in sequence from left to right and located in the same optical axis direction; the first lens group 1, the third lens group 3 and the fourth lens group 4 all have positive focal power, the second lens group 2 has negative focal power, the fourth lens group 4 includes a focusing group 42 having positive focal power, the first lens group 1 and the fourth lens group 4 are fixed focal length lens groups, the second lens group 2 and the third lens group 3 are variable focal length lens groups capable of moving along the optical axis direction, and the second lens group 2 and the third lens group 3 are mounted on mechanical devices such as a space cam in a lens barrel to realize the movement of the second lens group 2 and the third lens group 3 so as to further achieve the purpose of zooming; the second lens group 2 and the third lens group 3 are moved to vary the interval of the lens groups to vary the magnification between the wide-angle end and the telephoto end of the zoom system.

In one embodiment, the focal length of the focusing group 42 is 80mm, the distance from the surface close to the fourth single lens 41 is 8.2mm, and the distance from the surface close to the fifth single lens 43 is 11.2 mm.

In one embodiment, the focal length of the zoom system is f, the entrance pupil diameter is D, where f is 20mm to 70mm, and D/f is 1/3.2, which belongs to a lens index and is a conventional experimental setting.

In one embodiment, the length of the full target surface 5 is 20mm, the distance between the full target surface 5 and the fourth cemented mirror 44, that is, the back intercept is greater than or equal to 46.5mm, in this embodiment, the flange distance of the F-bayonet is 46.5mm, the back intercept needs to be greater than the flange distance of the F-bayonet, and the design difficulty increases as the flange distance of the F-bayonet increases.

Other parts and the using process are the same as those of the first embodiment, and are not described herein.

EXAMPLE III

Still another large-field-of-view long-rear-intercept zoom system with rear group focusing, as shown in fig. 1 to 3, includes a first lens group 1, a second lens group 2, a third lens group 3, a stop 6, a fourth lens group 4 and a full target surface 5, which are arranged in sequence from left to right and located in the same optical axis direction; the first lens group 1, the third lens group 3 and the fourth lens group 4 all have positive focal power, the second lens group 2 has negative focal power, the fourth lens group 4 includes a focusing group 42 having positive focal power, the first lens group 1 and the fourth lens group 4 are fixed focal length lens groups, the second lens group 2 and the third lens group 3 are variable focal length lens groups capable of moving along the optical axis direction, and the second lens group 2 and the third lens group 3 are mounted on mechanical devices such as a space cam in a lens barrel to realize the movement of the second lens group 2 and the third lens group 3 so as to further achieve the purpose of zooming; the second lens group 2 and the third lens group 3 are moved to vary the interval of the lens groups to vary the magnification between the wide-angle end and the telephoto end of the zoom system.

In one embodiment, the focal length of the focusing group 42 is 85mm, the distance from the surface close to the fourth single lens 41 is 10.2mm, and the distance from the surface close to the fifth single lens 43 is 13.2 mm.

In one embodiment, the focal length of the zoom system is f, the entrance pupil diameter is D, where f is 70mm to 150mm, and D/f is 1/2.6, which belongs to a lens index and is a conventional experimental setting.

In one embodiment, the length of the full target surface 5 is 25mm, and the distance from the full target surface 5 to the fourth cemented mirror 44, i.e. the back intercept, is equal to or greater than 46.5 mm.

Other parts and the using process are the same as those of the first embodiment, and are not described herein.

Example four

The invention further provides an optical zoom lens, which comprises the rear group focused large-view-field long-rear-intercept zoom system described in any one of the first embodiment to the third embodiment, and light beams reflected by a target are imaged on a full target surface 5 after passing through the rear group focused large-view-field long-rear-intercept zoom system.

Varying the interval of each lens group to change the magnification between the wide-angle end and the telephoto end; correcting image plane position variation under different object distances by moving the focusing group 42; the focusing group 42 can realize the focusing of the zoom system by selecting a single lens, so that focusing structural members and driving structures are reduced, the cost of the system is greatly reduced, and the practicability is high; the lenses in the zoom system are made of conventional glass materials, the two variable-focus lens groups move in a certain mode under the condition of less lens number, so that the process of miniaturization, large view field and long rear intercept zooming is realized, the imaging performance is improved, and the zoom lens system has the advantages of simple structure, easiness in assembly, high transmittance and the like, is suitable for mass production, and has wide market prospect.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (10)

1. A rear group focused large field of view long rear intercept zoom system, characterized by: the lens comprises a first lens group (1), a second lens group (2), a third lens group (3), a diaphragm (6), a fourth lens group (4) and a full target surface (5) which are arranged from left to right in sequence and are positioned in the same optical axis direction; wherein the content of the first and second substances,

the first lens group (1), the third lens group (3) and the fourth lens group (4) all have positive focal power, the second lens group (2) has negative focal power, and the fourth lens group (4) comprises a focusing group (42) having positive focal power;

the first lens group (1) and the fourth lens group (4) are fixed and fixed focal length lens groups, and the second lens group (2) and the third lens group (3) are variable focal length lens groups capable of moving along the optical axis direction; changing the interval of each lens group by moving the second lens group (2) and the third lens group (3) so as to change the magnification between the wide-angle end and the telephoto end of the zoom system; by moving the focusing group (42), image plane position variations are corrected for different object distances.

2. A rear group focused large field of view long rear intercept zoom system of claim 1, wherein: the first lens group (1) comprises a first cemented lens (11) and a first single lens (12) which correspond to each other, wherein the first lens of the first cemented lens (11) is a concave lens made of ZF4_ CHINA material, the second lens is a convex lens made of HQK3_ CDGM material, and the first single lens (12) is a convex lens made of ZK series material.

3. A rear group focused large field of view long rear intercept zoom system of claim 1, wherein: the second lens group (2) comprises a second single lens (21) and a second cemented lens (22) which correspond to each other, wherein the second single lens (21) is a concave lens made of HZK21_ CDGM material, the first lens of the second cemented lens (22) is a concave lens made of HZK3_ CDGM material, and the second lens is a convex-concave lens made of high-refractive-index low-dispersion material.

4. A rear group focused large field of view long rear intercept zoom system of claim 1, wherein: the third lens group (3) comprises a third single lens (31) and a third cemented lens (32) which correspond to each other, wherein the third single lens (31) is a convex lens made of a material of LAF series, the first lens of the third cemented lens (32) is a convex lens made of a material of HZBAF3_ CDGM, and the second lens is a concave lens made of a material of ZF4_ CHINA.

5. A rear group focused large field of view long rear intercept zoom system of claim 1, wherein: the fourth lens group (4) further comprises a fourth single lens (41), a fifth single lens (43) and a fourth cemented lens (44) which correspond to each other, wherein the fourth single lens (41) is a concave lens made of a material of the LAK series, the focusing group (42) is a concave-convex lens made of a material of HQK3L _ CDGM, the fifth single lens (43) is a convex lens made of a material of HQK3L _ CDGM, a first lens of the fourth cemented lens (44) is a convex lens made of a material of HQK3L _ CDGM, and a second lens is a concave lens made of a material of HZF6_ CDGM.

6. A rear group focused large field of view long rear intercept zoom system of claim 5, wherein: the focusing group (42) is a single lens made of HQK3L materials, the focal length is 80-85 mm, the distance between one surface close to the fourth single lens (41) and the fourth single lens (41) is 8.2-10.2 mm, and the distance between one surface close to the fifth single lens (43) and the fifth single lens (43) is 11.2-13.2 mm.

7. A rear group focused large field of view long rear intercept zoom system as claimed in any one of claims 1 to 6, wherein: and setting the focal length of the zoom system as f and the diameter of an entrance pupil as D, wherein the value range of f is 20-150 mm, and D/f is 1/3.2-1/2.6.

8. A rear group focused large field of view long rear intercept zoom system of claim 6, wherein: the length of the full target surface (5) is 20-25 mm, and the distance from the full target surface (5) to the fourth cemented mirror (44), namely the back intercept, is more than or equal to 46.5 mm.

9. A rear group focused large field of view long rear intercept zoom system of claim 1, wherein: the full field angle at the wide angle end is larger than or equal to 60 degrees, and the zoom ratio is larger than or equal to 7.5.

10. An optical zoom lens, characterized in that: a large field of view long rear intercept zoom system comprising a rear set of foci as claimed in any one of claims 1 to 9, through which the light beam reflected by the target is imaged onto the full target surface (5).

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