阅读说明：本技术 一种大口径透射式中波制冷红外连续变焦热像仪 (Large-caliber transmission type medium-wave refrigeration infrared continuous zooming thermal imager ) 是由 刘伟 焦洋洋 郭得福 闫福文 段程鹏 于 2021-10-26 设计创作，主要内容包括：本发明涉及一种大口径透射式中波制冷红外连续变焦热像仪,其目的是解决现有连续变焦红外热成像系统中存在折反式系统尺寸较大,装调难度大,中心区域能量损失严重,小口径的透射式系统通光口径小,能量探测能力低,作用距离相对较短的技术问题。该热像仪包括驱动单元、壳体、设置于壳体内的支架、固连于壳体前端面的前固定组、设置于壳体上的对外接口、通过所述支架安装的变倍组、补偿组、调焦组、反射组、中继组、探测器保护窗口H、滤光片I、冷阑J和机芯组；所述反射镜组包括两片相互垂直设置的反射镜,形成U型光路,将光路折转180°；驱动单元用于驱动变倍组、补偿组和调焦组沿光轴运动。(The invention relates to a large-aperture transmission type medium-wave refrigeration infrared continuous zooming thermal imager, and aims to solve the technical problems that a catadioptric system is large in size, high in assembly and adjustment difficulty, serious in energy loss of a central area, small in aperture transmission type system light-passing aperture, low in energy detection capability and relatively short in action distance in the existing continuous zooming infrared thermal imaging system. The thermal imager comprises a driving unit, a shell, a support arranged in the shell, a front fixing group fixedly connected to the front end face of the shell, an external interface arranged on the shell, a zoom group, a compensation group, a focusing group, a reflection group, a relay group, a detector protection window H, an optical filter I, a cold stop J and a machine core group, wherein the zoom group, the compensation group, the focusing group, the reflection group, the relay group, the detector protection window H, the optical filter I, the cold stop J and the machine core group are arranged through the support; the reflector group comprises two reflectors which are arranged vertically to form a U-shaped light path, and the light path is bent by 180 degrees; the driving unit is used for driving the zoom group, the compensation group and the focusing group to move along the optical axis.)

1. The utility model provides a large-diameter transmission-type medium wave refrigeration infrared continuous zooming thermal imager which characterized in that:

the device comprises a shell (11), a bracket (12) and a driving unit which are arranged in the shell (11), a front fixing group fixedly connected with the front end face of the shell (11), an external interface arranged on the shell (11), a zoom group (2), a compensation group (3), a focusing group (4), a reflection group (5), a relay group (6), a detector protection window H, an optical filter I, a cold stop group J and a core group (7) which are arranged through the bracket (12);

the machine core group (7) comprises a detector and a circuit board assembly and is used for finishing imaging, image processing, image output and driving unit control;

the front fixed mirror in the front fixed group, the zoom lens in the zoom group (2), the compensation lens in the compensation group (3), the focusing lens (42) in the focusing group (4), the reflecting mirror in the reflecting group (5), the relay lens in the relay group (6), the detector protection window H, the optical filter I, the cold stop J and the image plane K of the detector are sequentially arranged along an optical path;

the circuit board assembly outputs images outwards through an external interface;

the reflection group (5) comprises two reflectors which are arranged vertically to form a U-shaped light path, and the light path is bent by 180 degrees;

the driving unit comprises a zoom driving component, a compensation driving component and a focusing driving component which are respectively used for driving the zoom group (2), the compensation group (3) and the focusing group (4) to move along an optical axis, the relative movement of the zoom group (2) and the compensation group (3) is used for realizing continuous zooming, and the movement of the focusing group (4) is used for realizing high-temperature and low-temperature image motion compensation.

2. The large-caliber transmissive medium-wave refrigeration infrared continuous zooming thermal imager according to claim 1, wherein:

the front fixed mirror is a meniscus silicon positive lens A with a convex surface facing an object space and is used for converging light rays;

the zoom lens is a biconcave negative germanium lens B and is used for changing the focal length;

the compensation mirror is a biconvex positive silicon lens C and is used for compensating image motion caused in the zooming process;

the focusing lens (42) is a negative germanium lens D with a concave surface facing the image space, is used for finishing the first imaging and achieves the purpose of image surface high-low temperature compensation by moving along the axial direction;

the relay group (6) comprises 3 relay lenses, namely a biconvex positive silicon lens E, a biconcave negative zinc sulfide lens F and a biconvex positive chalcogenide lens G which are sequentially arranged along a light path and are used for completing diaphragm matching, carrying out secondary imaging and correcting residual aberration.

3. The large-caliber transmissive medium-wave refrigeration thermal infrared continuous zoom imager according to claim 1 or 2, characterized in that:

the zooming driving assembly and the compensation driving assembly have the same structure and respectively comprise a precision guide rail (81), a sliding block, a motor (83), a screw (84), a screw nut (85) and a nut adaptor (86); the motor (83) is arranged on the bracket (12);

the screw (84) and the output shaft of the motor (83) are integrally arranged, the screw (84) is fixed in the bracket (12) through a bearing (82), and the screw nut (85) is arranged on the screw (84);

the bottom of the sliding block is connected with a screw nut (85) through the nut adaptor (86), and the rotary motion of the motor (83) is converted into the linear motion of the sliding block;

the zoom group (2) comprises a zoom lens frame (21) and a lens barrel and a zoom lens of the zoom lens arranged in the zoom lens frame (21); the zooming mirror frame (21) is fixed on a slide block of the zooming driving component;

the compensation group (3) comprises a compensation lens frame (31), and a lens barrel and a compensation lens of the compensation lens arranged in the compensation lens frame (31); the compensation mirror frame (31) is fixed on a sliding block of the compensation driving component.

4. The large-caliber transmission-type medium-wave refrigeration thermal infrared continuous zooming imager according to claim 3, wherein:

the focusing driving assembly comprises a cam cylinder (91), a large gear ring (92), a guide pin (93), a focusing motor (94), a focusing gear (95) and a cam retainer ring (96);

the focusing group (4) comprises a focusing frame (41), and a lens barrel of the focusing lens (42) and the focusing lens (42) which are arranged in the focusing frame (41), wherein two straight grooves which are parallel to an optical axis and symmetrical by taking the optical axis as a center are axially arranged on the outer wall of the focusing frame (41) and are used for limiting the rotation motion of the lens barrel of the focusing lens (42);

the cam cylinder (91) and the large gear ring (92) are sequentially sleeved on the periphery of the focusing lens frame (41) from inside to outside, the cam cylinder (91), the focusing lens frame (41) and the lens barrel of the focusing lens (42) are radially fixed through the guide pin (93), two circumferential spiral curve grooves are formed in the inner wall of the cam cylinder (91), a structure similar to a nut and a screw is formed, and the structure is used for controlling the lens barrel of the focusing lens (42) to move along the direction of the curve grooves;

the cam retainer ring (96) is fixedly connected with the periphery of the focusing lens frame (41) to axially position the cam barrel (91);

the focusing gear (95) is arranged on an output shaft of the focusing motor (94);

the focusing gear (95) is meshed with the large gear ring (92) to convert the rotary motion of the focusing motor (94) into the linear motion of the focusing lens frame (41).

5. The large-caliber transmissive medium-wave refrigeration infrared continuous zooming thermal imager according to claim 4, wherein:

the total moving stroke of the zoom lens driven by the zoom driving component is 135.5 mm.

6. The large-caliber transmissive medium-wave refrigeration infrared continuous zooming thermal imager of claim 5, wherein:

the total movement stroke of the compensation driving component for driving the compensation mirror to move is 45.6 mm.

7. The large-caliber transmissive medium-wave refrigeration infrared continuous zooming thermal imager of claim 6, wherein:

the incidence surface of the zoom lens, the exit surface of the compensating lens, the exit surface of the focusing lens and the exit surfaces of the 3 relay lenses are even aspheric surfaces;

the incident plane surface of the front fixed mirror is plated with a hard film;

the reflecting surface of the reflecting mirror is plated with a reflecting film;

and the emergent surface of the front fixed mirror, the incident surface and the emergent surface of the zoom lens, the incident surface and the emergent surface of the compensating lens, the incident surface and the emergent surface of the focusing lens and the incident surface and the emergent surface of the 3 relay lenses are all plated with antireflection films.

Technical Field

The invention relates to an infrared thermal imaging technology, in particular to a large-caliber transmission type medium wave refrigeration infrared continuous zooming thermal imager which can be carried on equipment such as a theodolite, a turntable and the like and is mainly used for searching, tracking and measuring.

Background

In recent years, continuous zooming infrared thermal imaging systems have been widely used in many ways, and related technologies have been rapidly developed. The continuous zooming thermal imager can realize large-view-field searching and small-view-field tracking, has good imaging effect in the zooming process, cannot lose targets, and has the requirements and effects which cannot be met by fixed-focus thermal imagers and multi-view-field thermal imagers.

The generally required longer detection distance, higher detection sensitivity, higher resolution and longer action distance of the thermal infrared imager put higher requirements on the imaging resolution of the system. At present, a long-focus imaging system is mostly a catadioptric system or a small-caliber transmission-type system, wherein the catadioptric system can achieve a very long focus, but has a large size, high installation and adjustment difficulty and serious energy loss in a central area; the small-aperture transmission system has the advantages of long focal length, compact structure, small light-passing aperture, low energy detection capability and relatively short operating distance.

Disclosure of Invention

The invention aims to solve the technical problems that a catadioptric system is large in size, high in assembly and adjustment difficulty, serious in energy loss of a central area, small in light transmission aperture of a small-aperture transmission system, low in energy detection capability and relatively short in action distance in the conventional continuous zooming infrared thermal imaging system, and provides a large-aperture transmission type medium-wave refrigeration infrared continuous zooming thermal imager.

In order to solve the technical problems, the technical solution provided by the invention is as follows:

a large-caliber transmission type medium-wave refrigeration infrared continuous zooming thermal imager is characterized in that:

the device comprises a shell, a support and a driving unit which are arranged in the shell, a front fixing group fixedly connected with the front end face of the shell, an external interface arranged on the shell, a zoom group, a compensation group, a focusing group, a reflection group, a relay group, a detector protection window H, an optical filter I, a cold diaphragm J and a machine core group which are arranged through the support;

the movement assembly comprises a detector and a circuit board assembly and is used for finishing imaging, image processing, image output and drive unit control;

the front fixed mirror in the front fixed group, the zoom lens in the zoom group, the compensation lens in the compensation group, the focusing lens in the focusing group, the reflecting mirror in the reflecting group, the relay lens in the relay group, the detector protection window H, the optical filter I, the cold stop J and the image surface K of the detector are sequentially arranged along an optical path;

the circuit board assembly outputs images outwards through an external interface;

the reflector group comprises two reflectors which are arranged vertically to form a U-shaped light path, and the light path is bent by 180 degrees;

the driving unit comprises a zoom driving component, a compensation driving component and a focusing driving component which are respectively used for driving the zoom group, the compensation group and the focusing group to move along the optical axis, the relative movement of the zoom group and the compensation group is used for realizing continuous zooming, and the movement of the focusing group is used for realizing high-temperature and low-temperature image motion compensation.

Furthermore, the front fixed mirror is a meniscus silicon positive lens A with a convex surface facing the object space, and is used for converging light rays;

the zoom lens is a biconcave negative germanium lens B and is used for changing the focal length;

the compensation mirror is a biconvex positive silicon lens C and is used for compensating image motion caused in the zooming process;

the focusing lens is a negative germanium lens D with a concave surface facing the image space, is used for finishing the first imaging and achieves the purpose of image surface high-low temperature compensation through axial movement;

the relay group comprises 3 relay lenses, namely a biconvex positive silicon lens E, a biconcave negative zinc sulfide lens F and a biconvex positive chalcogenide lens G which are sequentially arranged along a light path and are used for completing diaphragm matching, carrying out secondary imaging and correcting residual aberration.

Furthermore, the zooming driving assembly and the compensation driving assembly have the same structure and respectively comprise a precision guide rail, a sliding block, a motor, a screw rod, a screw nut and a nut adapter piece; the motor is arranged on the bracket;

the screw rod and the output shaft of the motor are integrally arranged, the screw rod is fixed in the bracket through a bearing, and the screw rod nut is arranged on the screw rod;

the bottom of the sliding block is connected with the screw nut through the nut adapter, and the rotary motion of the motor is converted into the linear motion of the sliding block;

the zooming group comprises a zooming lens frame, a lens cone of the zooming lens and the zooming lens, wherein the lens cone and the zooming lens are arranged in the zooming lens frame; the zoom lens frame is fixed on a sliding block of the zoom driving component;

the compensation group comprises a compensation lens frame, a lens cone of the compensation lens and the compensation lens, wherein the lens cone and the compensation lens are arranged in the compensation lens frame; the compensation mirror frame is fixed on a sliding block of the compensation driving component.

Further, the focusing driving assembly comprises a cam barrel, a large gear ring, a guide pin, a focusing motor, a focusing gear and a cam retainer ring;

the focusing group comprises a focusing frame, a lens cone of the focusing lens and the focusing lens, wherein the lens cone of the focusing lens and the focusing lens are arranged in the focusing frame;

the cam barrel and the large gear ring are sequentially sleeved on the periphery of the focusing lens frame from inside to outside to be fixedly connected, the cam barrel, the focusing lens frame and the focusing lens barrel are radially fixed through the guide pin, and two circumferential spiral curved grooves are formed in the inner wall of the cam barrel to form a structure similar to a nut and a screw rod and used for controlling the focusing lens barrel to move along the direction of the curved grooves;

the cam retainer ring is in threaded connection with the periphery of the focusing lens frame to axially position the cam barrel;

the focusing gear is arranged on an output shaft of the focusing motor;

the focusing gear is meshed with the large gear ring to convert the rotary motion of the focusing motor into the linear motion of the focusing frame.

Further, the total moving stroke of the variable-magnification driving component for driving the variable-magnification mirror to move is 135.5 mm.

Further, the total moving stroke of the compensation driving component for driving the compensation mirror to move is 45.6 mm.

Furthermore, the incidence surface of the zoom lens, the emergence surface of the compensating lens, the emergence surface of the focusing lens and the emergence surfaces of the 3 relay lenses are even aspheric surfaces;

the incident plane surface of the front fixed mirror is plated with a hard film;

the reflecting surface of the reflecting mirror is plated with a reflecting film;

and the emergent surface of the front fixed mirror, the incident surface and the emergent surface of the zoom lens, the incident surface and the emergent surface of the compensating lens, the incident surface and the emergent surface of the focusing lens and the incident surface and the emergent surface of the 3 relay lenses are all plated with antireflection films.

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

1. according to the large-aperture transmission type medium-wave refrigeration infrared continuous zooming thermal imager provided by the invention, the secondary imaging continuous zooming system is adopted, and on the premise of meeting the imaging quality, an optical system only adopting 7 lenses is obtained, the shortest focal length is less than or equal to 57mm, the longest focal length is more than or equal to 610mm, and the clear aperture is more than or equal to 305 mm. The design in the optical system ensures that the cold diaphragms are matched by 100 percent, and the energy loss of light beams is reduced. The direction of the optical axis of the thermal imager is changed through the two plane reflectors to form a U-shaped light path, so that the length and the volume of the system can be effectively reduced; the F number of the continuous zooming thermal imager is 2.0, the focal length is larger than or equal to 610mm, the clear aperture is larger than or equal to 305mm, the light transmission amount of the system is increased, the sensitivity is improved, the long focal length and the large clear aperture are realized, and the structure is compact while the high resolution is realized; the working temperature is between minus 45 ℃ and plus 65 ℃.

2. The large-aperture transmission type medium-wave refrigeration infrared continuous zooming thermal imager provided by the invention has the advantages that the zooming mode is simple, only two lenses participate in zooming, the movement load is small, the consistency of the optical axis is easy to guarantee, the continuous zooming driving is realized by matching the stepping motor with the lead screw (screw) and the guide rail, the stability of the moving lens group is improved, and the offset of the optical axis in the zooming process is smaller than 0.04 mrad.

3. The large-aperture transmission type medium-wave refrigeration infrared continuous zooming thermal imager provided by the invention has the advantages that the number of used lenses is small, only seven lenses are used, the requirements on machining, assembling and adjusting tolerances are not high, and the machining, assembling and adjusting difficulty is small.

4. The large-caliber transmission type medium-wave refrigeration infrared continuous zooming thermal imager provided by the invention uses conventional infrared materials, namely silicon, germanium, zinc sulfide and sulfur, and is low in processing difficulty and risk.

Drawings

FIG. 1 is a schematic structural view of a large-caliber transmission type medium-wave refrigeration thermal infrared continuous zooming imager of the present invention;

FIG. 2 is a schematic diagram of the position of a lens in a large-aperture transmission-type medium-wave refrigeration thermal infrared continuous zoom imager according to the present invention;

FIG. 3 is a schematic structural diagram of a zoom driving assembly, a compensation driving assembly and a focusing driving assembly in the large-aperture transmission type medium-wave refrigeration thermal infrared continuous zoom imager of the present invention;

FIG. 4 is a schematic structural diagram of a focusing driving assembly and a focusing set in the large-aperture transmission-type medium-wave refrigeration thermal infrared continuous zooming imager of the invention;

description of reference numerals:

1-front fixing group, 2-zooming group, 3-compensation group, 4-focusing group, 5-reflection group, 6-relay group, 7-core group, 11-shell and 12-bracket;

41-focusing lens frame, 42-focusing lens, 21-zooming lens frame and 31-compensating lens frame;

81-precision guide rail, 82-bearing, 83-motor, 84-screw, 85-screw nut and 86-nut adapter;

91-cam cylinder, 92-big gear ring, 93-guide pin, 94-focusing motor, 95-focusing gear, 96-cam retainer ring.

Detailed Description

The invention is further described below with reference to the figures and examples.

The invention relates to a large-caliber transmission type medium-wave refrigeration infrared continuous zooming thermal imager, which comprises a shell 11, a support 12 and a driving unit which are arranged in the shell 11, a front fixing group 1 which is fixedly connected with the front end surface of the shell 11, an external interface which is arranged on the shell 11, a zoom group 2, a compensation group 3, a focusing group 4, a reflection group 5, a relay group 6, a detector protection window H, an optical filter I, a cold stop J and a machine core group 7 which are arranged through the support 12; the movement group 7 comprises a detector and a circuit board assembly and is used for finishing imaging, image processing, image output and drive unit control, namely the movement group 7 is mainly used for realizing photoelectric signal conversion, converting optical signals into images, and performing image processing and image output; the front fixed mirror in the front fixed group 1, the zoom lens in the zoom group 2, the compensation lens in the compensation group 3, the focusing lens 42 in the focusing group 4, the reflecting mirror in the reflecting group 5, the relay lens in the relay group 6, the detector protection window H, the optical filter I, the cold stop J and the image plane K of the detector are sequentially arranged along an optical path; the circuit board assembly outputs images outwards through an external interface; the reflector group is positioned between the focusing group 4 and the relay group 6, and comprises two reflectors which are arranged vertically, namely a reflector M and a reflector N, so as to form a U-shaped light path and turn the light path by 180 degrees; the driving unit comprises a zoom driving component, a compensation driving component and a focusing driving component which are respectively used for driving the zoom group 2, the compensation group 3 and the focusing group 4 to move along an optical axis, the relative movement of the zoom group 2 and the compensation group 3 is used for realizing continuous zooming, in the continuous zooming thermal imager, the zoom group 2 and the compensation group 3 do relative continuous movement, the focal length continuously changes in the movement process, but the image surface position remains unchanged, and the movement of the focusing group 4 is used for realizing high-temperature and low-temperature image motion compensation.

The front fixed mirror is a meniscus silicon positive lens A with a convex surface facing an object space and is used for converging light rays; the zoom lens is a biconcave negative germanium lens B and is used for changing the focal length in the continuous zoom lens; the compensation mirror is a biconvex positive silicon lens C and is used for compensating image motion caused in the zooming process; the focusing lens 42 is a negative germanium lens D with a concave surface facing the image space, and is used for completing the first imaging and achieving the purpose of image surface high-low temperature compensation through axial movement; the relay group 6 comprises 3 relay lenses, namely a biconvex positive silicon lens E, a biconcave negative zinc sulfide lens F and a biconvex positive chalcogenide lens G which are sequentially arranged along a light path and are used for completing diaphragm matching, carrying out secondary imaging and correcting residual aberration.

By adopting the structure of the invention, seven imaging components are sequentially arranged from an object side to an image side, namely a front fixed group 1, a zoom group 2, a compensation group 3, a focusing group 4, a reflection group 5, a relay group 6 and a movement group 7, light passes through five lens groups and reflector groups, passes through a detector protection window H, an optical filter I and a cold diaphragm J, and finally reaches an image surface K of the movement group 7.

The zooming driving assembly and the compensation driving assembly have the same structure and respectively comprise a precision guide rail 81, a sliding block, a motor 83, a screw 84, a screw nut 85 and a nut adapter 86; the motor 83 is arranged on the bracket 12; the motor 83, the screw 84, the screw nut 85 and the nut adaptor 86 are all positioned below the zooming group 2; the screw 84 and the output shaft of the motor 83 are integrally arranged, the screw 84 is fixed in the bracket 12 through the bearing 82, and the screw nut 85 is arranged on the screw 84; the bottom of the sliding block is connected with a screw nut 85 through the nut adaptor 86, and the rotary motion of the motor 83 is converted into the linear motion of the sliding block; the zoom group 2 comprises a zoom lens frame 21, and a lens barrel and a zoom lens of the zoom lens arranged in the zoom lens frame 21; the zoom lens frame 21 is fixed on a slide block of the zoom driving component, and the total moving stroke of the zoom driving component for driving the zoom lens to move is 135.5 mm; the compensation group 3 comprises a compensation lens frame 31 and a lens barrel and a compensation lens of the compensation lens arranged in the compensation lens frame 31; the compensation mirror frame 31 is fixed on a slide block of the compensation driving component, and the total moving stroke of the compensation driving component for driving the compensation mirror to move is 45.6 mm.

The focusing driving assembly comprises a cam cylinder 91, a large gear ring 92, a guide pin 93, a focusing motor 94, a focusing gear 95 and a cam retainer ring 96; the focusing group 4 comprises a focusing lens frame 41, and a lens barrel of the focusing lens 42 and the focusing lens 42 which are arranged in the focusing lens 42 frame 41, wherein two straight grooves which are parallel to an optical axis and symmetrical by taking the optical axis as a center are arranged on the outer wall of the focusing lens frame 41 along the axial direction and are used for limiting the rotation motion of the lens barrel of the focusing lens 42; the cam cylinder 91 and the large gear ring 92 are sequentially sleeved on the periphery of the focusing lens frame 41 from inside to outside, the cam cylinder 91, the focusing lens frame 41 and the focusing lens 42 lens barrel are radially fixed through the guide pin 93, and two circumferential spiral curved grooves are formed in the inner wall of the cam cylinder 91 to form a structure similar to a nut and screw rod and used for controlling the focusing lens 42 lens barrel to move along the direction of the curved grooves; the cam retainer ring 96 is fixedly connected with the periphery of the focusing lens frame 41 by using screws to axially position the cam cylinder 91; the focusing gear 95 is arranged on an output shaft of the focusing motor 94; the focus gear 95 is engaged with the large ring gear 92, and converts the rotational movement of the focus motor 94 into the linear movement of the focus lens frame 41. That is, after the focusing gear 95 is engaged with the large gear ring 92, the rotational motion of the focusing motor 94 is converted into the rotational motion of the cam cylinder 91, wherein the guide pins 93 disposed in the spiral curve groove of the cam cylinder 91 and the straight groove of the focusing lens frame 41 can only drive the lens barrel of the focusing lens 42 to make a linear motion along the optical axis because the rotational motion along the optical axis is limited by the straight groove.

The large-aperture transmission type medium-wave refrigeration infrared continuous zooming thermal imager provided by the invention adopts a secondary imaging mode for reducing the aperture of the lens A and ensuring the efficiency of a 100% cold diaphragm, the whole system adopts 7 lenses, the continuous change of focal lengths of 57-610 mm is met, the light-passing aperture is larger than or equal to 305mm, and the structure is simple and compact. FIG. 1 shows a block diagram of a thermal imager at a focal length of 610 mm.

The infrared core group 7 mainly realizes photoelectric signal conversion, converts optical signals into images, and performs image processing and image output; the zooming driving component mainly realizes driving control of the zooming group 2 to move along the axial direction; the compensation driving component mainly realizes the driving control of the compensation group 3 to move along the axial direction; the focusing driving component mainly realizes driving and controlling the focusing group 4 to move along the axial direction; the bracket 12 supports and fixes the internal component structure of the shell 11; the shell 11 supports the front fixing group 1 and the support 12 and simultaneously serves as an external interface for the main body of the complete thermal imager.

In order to ensure that the effects of wind and sand prevention and the like on the exposed surface of the thermal imager are met, the front surface of the lens A is plated with a hard film, in order to ensure high transmittance and reduce cold reflection, the reflecting surface of the reflecting mirror is plated with a reflecting film, and the other surfaces (the emergent surface of the front fixed mirror, the incident surface and the emergent surface of the zoom lens, the incident surface and the emergent surface of the compensating mirror, the incident surface and the emergent surface of the focusing mirror and the incident surface and the emergent surface of the 3 relay lenses) are uniformly plated with antireflection films. Table 1 is a 60mm/600mm optical structure parameter table.

TABLE 1, 60mm/600mm optical structure parameter table

The aspherical surfaces mentioned in the above lenses are all even-order aspherical surfaces, and the expression thereof is as follows:

where z is the distance vector from the aspheric surface vertex when the aspheric surface is at a position of height r in the optical axis direction, c represents the vertex curvature of the surface, equal to the inverse of the aspheric surface curvature radius, and c is 1/r₀K is a conic coefficient, k is 0, alpha₂、α₃、α₄、α₅、α₆Are high-order aspheric coefficients.

Table 2 shows aspheric coefficients of the surfaces S4, S6, S7, S14:

TABLE 2 aspheric coefficients table

Surface of	α2	α3	α4
				S3	3.9939e-8	-1.68348e-12	7.353607e-17
S6	6.532857e-8	-2.440704e-12	7.226834e-17
				S8	3.72096e-9	5.138704e-12	2.338759e-15
S12	5.35368e-6	9.451688e-10	-7.748325e-12
				S14	-5.6457e-7	-8.76021e-10	-3.987897e-10
S16	7.75523e-6	-1.869445e-8	7.677986e-11

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same, and it is obvious for a person skilled in the art to modify the specific technical solutions described in the foregoing embodiments or to substitute part of the technical features, and these modifications or substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions protected by the present invention.