CN219758581U - Area array scanning infrared optical system - Google Patents

Abstract

The utility model discloses an area array scanning infrared optical system, which comprises a lens group of a telescopic system, an azimuth scanning galvanometer, a pitching scanning galvanometer, a third imaging group, an optical window, a cold screen diaphragm and an image plane, wherein the lens group of the telescopic system, the azimuth scanning galvanometer, the pitching scanning galvanometer, the third imaging group, the optical window, the cold screen diaphragm and the image plane are sequentially arranged from an object space to an image space, and the cold screen diaphragm coincides with the exit pupil position of the third imaging group; the azimuth scanning galvanometer and the pitching scanning galvanometer are both in a fixed state and a reciprocating retrace state, and when the azimuth scanning galvanometer is in the fixed state and the pitching scanning galvanometer is in the reciprocating retrace state, the area array scanning infrared optical system can compensate the image movement in the pitching direction and keep the pitching angle stable; when both the azimuth scanning galvanometer and the pitching scanning galvanometer are in a reciprocating retrace state, the area array scanning infrared optical system simultaneously realizes the search of a two-dimensional airspace, and solves the problem of image rotation.

Description

Area array scanning infrared optical system

Technical Field

The utility model relates to the technical field of optics, in particular to an area array scanning infrared optical system.

Background

To realize the monitoring of the large-view-field airspace, the infrared array searching system must make full use of the characteristic of high imaging frame frequency of the area array detector, and the servo control mechanism is used for enabling the image output by the system to cover 360 degrees of azimuth and a certain pitching range, so that the imaging definition is ensured, and each frame of image output by the system has accurate azimuth angle and pitching angle information.

Under a stable platform, when the infrared search tracking system performs sea skimming low-altitude detection, the sea-sky connected part of the whole sea area is expected to be under the monitoring of the system. At the moment, the system only needs to perform 360-degree scanning detection on the azimuth, performs panoramic scanning by utilizing the azimuth searching turntable, is equipped with a compensation mirror to perform image motion compensation on the azimuth dimension, and sets a corresponding searching rate to ensure a certain overlapping rate between continuous images, so that 360-degree missed scanning on the azimuth is avoided. When the infrared searching and tracking system is positioned under a motion platform and influenced by ship shake, when the azimuth searching turntable performs 360-degree azimuth searching imaging, the pitching angle of a monitored area is not stable any more, the pitching angle of the area in certain azimuth is higher than 0 degrees, and the pitching angle of the area in other azimuth is lower than 0 degrees, so that sea-skimming low-altitude detection cannot be effectively completed.

Disclosure of Invention

The utility model mainly aims to provide an area array scanning infrared optical system, which aims to solve the problem of image rotation in the scanning process of the existing infrared area array searching system.

In order to achieve the above purpose, the utility model provides an area array scanning infrared optical system, wherein the area array scanning infrared optical system comprises a lens group of a telescopic system, an azimuth scanning galvanometer, a pitching scanning galvanometer, a three-time imaging group, an optical window, a cold screen diaphragm and an image plane which are sequentially arranged from an object side to an image side, and the cold screen diaphragm coincides with the exit pupil position of the three-time imaging group;

the azimuth scanning galvanometer and the pitching scanning galvanometer are both in a fixed state and a reciprocating flyback state, and the pitching scanning galvanometer is used for compensating the image movement in the pitching direction while compensating the image movement in the horizontal direction.

Optionally, the lens group of the telescopic system comprises a front fixed lens group, a zoom lens group, a compensation lens group and a rear fixed lens group which are sequentially arranged from an object space to an image space, wherein the zoom lens group and the compensation lens group can be movably arranged along the extending direction of the optical axis so as to realize continuous zooming of the area array scanning infrared optical system.

Optionally, the front fixed lens group includes a first front fixed lens and a second front fixed lens sequentially arranged from an object side to an image side;

the variable magnification lens group comprises a first variable magnification lens;

the compensating lens group comprises a first compensating lens and a second compensating lens which are sequentially arranged from an object space to an image space;

the rear fixed lens group comprises a first rear fixed lens, a second rear fixed lens and a third rear fixed lens with negative focal power, wherein the first rear fixed lens, the second rear fixed lens and the third rear fixed lens are sequentially arranged from an object space to an image space.

Optionally, the optical power of the first front fixed lens is positive, and the optical power of the second front fixed lens is negative;

the focal power of the first variable-power lens is negative;

the focal power of the first compensation lens is positive, and the focal power of the second compensation lens is negative;

the focal power of the first rear fixed lens is negative, the focal power of the second rear fixed lens is positive, and the focal power of the third rear fixed lens is negative.

Optionally, the first front fixed lens is a meniscus silicon lens, the second front fixed lens is a meniscus germanium lens, and concave surfaces of the first front fixed lens and the second front fixed lens face the image space;

the first zoom lens is a biconcave spherical silicon lens;

the first compensation lens is a biconvex aspheric silicon lens, the second compensation lens is a meniscus aspheric germanium lens, and the concave surface of the second compensation lens faces the object space;

the first rear fixed lens is a meniscus-type aspheric germanium lens, the concave surface of the first rear fixed lens faces to the object space, the second rear fixed lens is a biconvex aspheric silicon lens, and the third rear fixed lens is a biconcave aspheric germanium lens.

Optionally, the third imaging group includes a first lens with positive focal power, a second lens with positive focal power, a third lens with positive focal power and a fourth lens with negative focal power, which are sequentially arranged from the object side to the image side.

Optionally, the first lens is a meniscus spherical silicon lens, the second lens is a meniscus spherical silicon lens, the third lens is a biconvex aspheric silicon lens, the fourth lens is a meniscus aspheric germanium lens, wherein concave surfaces of the first lens and the fourth lens face the image space, and concave surfaces of the second lens face the object space.

Optionally, the exit pupil position of the lens group of the telescopic system is located near the azimuth scanning galvanometer;

the pitching scanning galvanometer is positioned in a parallel light path between the lens group of the telescopic system and the tertiary imaging group.

Optionally, the azimuth scanning galvanometer and the pitching scanning galvanometer are correspondingly arranged, so that the light beam incident from the object space is transmitted through the lens group of the telescopic system and then projected to the azimuth scanning galvanometer, and the light beam reflected by the azimuth scanning galvanometer is reflected by the pitching scanning galvanometer, so that the light beam reflected to the image space by the pitching scanning galvanometer is parallel and opposite to the propagation path of the light beam incident from the object space and passing through the lens group of the telescopic system.

Optionally, the focal length of the short focus of the area array scanning infrared optical system is f1, the length Jiao Jiaoju is f2, and the zoom ratio of the area array scanning infrared optical system is Γ, wherein Γ is more than 1 and less than or equal to 20.

In the technical scheme provided by the utility model, a lens group of a telescopic system, an azimuth scanning galvanometer, a pitching scanning galvanometer, a tertiary imaging group, an optical window, a cold screen diaphragm and an image plane are arranged, wherein the cold screen diaphragm is overlapped with the exit pupil position of the tertiary imaging group; the method comprises the steps that incident light is converted into parallel light beams through a lens group of a telescopic system and is projected to an azimuth scanning vibrating mirror, the azimuth scanning vibrating mirror bends an optical path and projects the light beams to a pitching scanning vibrating mirror, the scanning vibrating mirror and the pitching scanning vibrating mirror are both in a fixed state and a back-and-forth retrace state, when the azimuth scanning vibrating mirror and the pitching scanning vibrating mirror are both in the fixed state, the area array scanning infrared optical system is in a gaze tracking mode, and when in gaze, the lens group of the telescopic system can continuously zoom; when the azimuth scanning galvanometer is in a back-and-forth retrace state and the pitching scanning galvanometer is in a fixed state, the area array scanning infrared optical system is in a circumferential scanning searching mode; when the azimuth scanning galvanometer is in a fixed state and the pitching scanning galvanometer is in a reciprocating retrace state, the area array scanning infrared optical system can compensate the image movement in the pitching direction and keep the pitching angle stable; when both the azimuth scanning galvanometer and the pitching scanning galvanometer are in a reciprocating retrace state, the area array scanning infrared optical system simultaneously realizes the search of a two-dimensional airspace, and solves the problem of image rotation.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a diagram of an infrared search tracking system;

FIG. 2 is a schematic diagram of an area array scanning infrared optical system according to an embodiment of the present utility model at a wide-angle end;

FIG. 3 is a schematic diagram of an embodiment of an area array scanning infrared optical system provided by the present utility model at a telescopic end;

FIG. 4 is a graph of a transfer function corresponding to the short focal system f60mm of FIG. 2;

FIG. 5 is a graph of a transfer function corresponding to the mid system f200mm of FIG. 2;

fig. 6 is a graph of transfer functions corresponding to the tele system f600mm in fig. 3.

Reference numerals illustrate:

reference numerals	Name of the name	Reference numerals	Name of the name
				1	Front fixed lens group	5	Direction scanning galvanometer
1-1	First front fixed lens	6	Pitching scanning galvanometer
				1-2	Second front fixed lens	7	Three imaging group
2	Variable magnification lens group	7-1	First lens
				3	Compensation lens group	7-2	Second lens
3-1	First compensating lens	7-3	Third lens
				3-2	Second compensating lens	7-4	Fourth lens
4	Rear fixed lens group	8	Optical window
				4-1	First rear fixed lens	9	Cold screen diaphragm
4-2	Second rear fixed lens	10	Image plane
				4-3	Third rear fixed lens

The achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present utility model, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

When the infrared array search system performs sea-skimming low-altitude detection, the pitching angle of a scanned image is required to be kept stable under the geodetic coordinate system by a correction device due to the change of the pitching angle of a monitoring area caused by ship pitching, the pitching angle lower than 0 DEG is raised, and the pitching angle higher than 0 DEG is pulled down at the same time, so that the stable pitching angle is kept in the geodetic coordinate system.

The whole outer frame of the two-dimensional infrared searching and tracking system is driven by an azimuth motor, and the inner frame is driven by a pitching motor. And the infrared searching and tracking system performs panoramic scanning (pitch angle is 0 degree) under the stable platform, so that the large-view-field monitoring of 360-degree azimuth is realized, when the continuous scanning scheme is uncompensated, serious tailing exists in the image, and the scanning motion of the azimuth searching turntable can bring the movement of the scene image in the horizontal direction of the detector in the integral time. At this time, there is only image shift, and the image is not rotated, so there is no image rotation. If the speed of the external frame azimuth searching turntable of the system is kept unchanged, the pitching motor of the internal frame is controlled to keep the pitching angle of the infrared searching and tracking system at 90 degrees, the target surface of the detector faces upwards, the rotation of the azimuth searching turntable enables the detector to rotate around the visual axis, the system images the same visual field at different rotation angles, and therefore the image rotation problem exists. In the process that the pitch angle of the azimuth searching turntable rises from 0 to 90, the image shift problem is gradually converted into the image rotation problem.

In order to solve the above-mentioned problems, the present utility model provides an area-array scanning infrared optical system, and fig. 2 to 6 are specific embodiments of the area-array scanning infrared optical system provided by the present utility model.

Referring to fig. 2, the area array scanning infrared optical system includes a lens group of a telescopic system, an azimuth scanning galvanometer 5, a pitching scanning galvanometer 6, a third imaging group 7, an optical window 8, a cold screen diaphragm 9 and an image plane 10, which are sequentially arranged from an object side to an image side, wherein the cold screen diaphragm 9 coincides with an exit pupil position of the third imaging group 7; the azimuth scanning galvanometer 5 and the pitching scanning galvanometer 6 have a fixed state and a back-and-forth retrace state, and the pitching scanning galvanometer 6 is used for compensating the image shift in the pitching direction while compensating the image shift in the horizontal direction.

In the technical scheme provided by the utility model, a lens group of a telescopic system, an azimuth scanning galvanometer 5, a pitching scanning galvanometer 6, a tertiary imaging group 7, an optical window 8, a cold screen diaphragm 9 and an image plane 10, wherein the cold screen diaphragm 9 coincides with the exit pupil position of the tertiary imaging group 7; the incident light is converted into parallel light beams through a lens group of a telescopic system and is projected to the azimuth scanning galvanometer 5, the azimuth scanning galvanometer 5 is used for turning the light path and projecting the light beams to the pitching scanning galvanometer 6, the scanning galvanometer and the pitching scanning galvanometer 6 are both in a fixed state and a back-and-forth retrace state, when the azimuth scanning galvanometer 5 and the pitching scanning galvanometer 6 are both in the fixed state, the area array scanning infrared optical system is in a gaze tracking mode, and when in gaze, the telescopic system lens group only carries out continuous zooming tracking imaging; when the azimuth scanning galvanometer 5 is in a back and forth retrace state and the pitching scanning galvanometer 6 is in a fixed state, the area array scanning infrared optical system is in a circumferential scanning searching mode, namely a motor drives the azimuth scanning galvanometer 5 to scan back and forth along an effective scanning half angle alpha from a zero point; when the azimuth scanning galvanometer 5 is in a fixed state and the pitching scanning galvanometer 6 is in a reciprocating retrace state, the area array scanning infrared optical system can compensate the image shift in the pitching direction and keep the pitching angle stable; when both the azimuth scanning galvanometer 5 and the pitching scanning galvanometer 6 are in a reciprocating retrace state, the area array scanning infrared optical system simultaneously realizes the search of a two-dimensional airspace, and solves the problem of image rotation.

It should be noted that, referring to fig. 1, the azimuth 360 ° panoramic search realizes azimuth large field monitoring by means of azimuth motors, the azimuth compensation mirror overcomes the image tailing in the horizontal direction in the integration time, the pitching pointing mirror completes the stabilization of the elevation angle in the geodetic coordinate system, and the pitching compensation mirror completes the image motion compensation in the pitching direction. In the area array scanning infrared optical system, under the condition that pitching direction is stable under a movable base, a pitching mechanism is added on the basis of azimuth scanning to realize target detection of a two-dimensional airspace, and the horizontal image movement is compensated and the pitching direction image movement is compensated at the same time, so that two-dimensional image movement compensation is realized.

It should be further noted that, in order to enable the planar array scanning infrared optical system to achieve better detection performance, the system adopts a planar array 640 x 512 refrigeration type infrared detector. And in order to suppress background radiation, the aperture diaphragm of the area array scanning infrared optical system is 100% matched with the cold diaphragm of the detector. Meanwhile, in order to reduce the volume of the area array scanning infrared optical system, the caliber of a first lens at the object side of the area array scanning infrared optical system can be reduced, and an entrance pupil is designed on the front end face of the first lens. Further to reduce the image problems caused by the size and installation errors of the azimuth scanning galvanometer 5 and the pitching scanning galvanometer 6, a retrace structure form of an image space scanning mirror is adopted, namely the azimuth scanning galvanometer 5 and the pitching scanning galvanometer 6 are introduced into parallel light paths in a front telescope and a rear convergence assembly.

Specifically, in this embodiment, the lens group of the telescopic system includes a front fixed lens group 1, a variable magnification lens group 2, a compensation lens group 3 and a rear fixed lens group 4 that are sequentially arranged from the object side to the image side, where the variable magnification lens group 2 and the compensation lens group 3 can be movably disposed along the extending direction of the optical axis, so as to realize continuous zooming of the area array scanning infrared optical system. Specifically, the zoom lens group 2 moves toward the object direction, the compensation lens group 3 moves toward the image direction, and the focal length of the telescopic lens group becomes short; the zoom lens group 2 moves towards the image space, the compensation lens group 3 moves towards the object space, and the focal length of the lens group of the telescopic system is shortened, namely, the area array scanning infrared optical system can realize multi-gear zooming two-dimensional area array scanning and continuous zooming gaze tracking through the combined movement of the zoom lens group 2 and the compensation lens group 3.

More specifically, in an embodiment, the front fixed lens group 1 includes a first front fixed lens 1-1 and a second front fixed lens 1-2 arranged in order from an object side to an image side; the variable magnification lens group 2 comprises a first variable magnification lens; the compensating lens group 3 comprises a first compensating lens 3-1 and a second compensating lens 3-2 which are sequentially arranged from an object space to an image space; the rear fixed lens group 4 comprises a first rear fixed lens 4-1, a second rear fixed lens 4-2 and a third rear fixed lens 4-3 with negative focal power, which are sequentially distributed from the object space to the image space.

It should be noted that, in order to reduce the lens size of the front fixed lens group 1, the entrance pupil position of the area array scanning infrared optical system is located on the front surface of the first front fixed lens 1-1, and the system adopts a three-time imaging structure.

In this embodiment, the optical power of the first front fixed lens 1-1 is positive, and the optical power of the second front fixed lens 1-2 is negative; the focal power of the first variable-power lens is negative; the focal power of the first compensation lens 3-1 is positive, and the focal power of the second compensation lens 3-2 is negative; the focal power of the first rear fixed lens 4-1 is negative, the focal power of the second rear fixed lens 4-2 is positive, and the focal power of the third rear fixed lens 4-3 is negative. Through reasonable distribution of lens focal power, glass shape and material collocation are adjusted, effective achromatism, chromatic dispersion and secondary spectrum are realized, and spherical aberration, coma aberration, astigmatism and the like on each lens are compensated and counteracted, so that the effect of clear imaging is achieved.

The variable magnification lens group 2 may be a single lens or a lens group composed of a plurality of lenses. The compensation lens group 3 can be a lens group formed by a single lens or a plurality of lenses.

More specifically, since the high-purity germanium single crystal has a high refractive index, is transparent to infrared rays, and does not transmit visible light and ultraviolet rays, in this embodiment, the first front fixed lens 1-1 is a meniscus silicon lens, the second front fixed lens 1-2 is a meniscus germanium lens, and the concave surfaces of the first front fixed lens 1-1 and the second front fixed lens 1-2 face the image side; the first zoom lens is a biconcave spherical silicon lens; the first compensation lens 3-1 is a biconvex aspheric silicon lens, the second compensation lens 3-2 is a meniscus aspheric germanium lens, and the concave surface of the second compensation lens 3-2 faces the object space; the first rear fixed lens 4-1 is a meniscus type aspheric germanium lens, the concave surface of the first rear fixed lens 4-1 faces the object space, the second rear fixed lens 4-2 is a biconvex aspheric silicon lens, and the third rear fixed lens 4-3 is a biconcave aspheric germanium lens.

Specifically, in a specific embodiment, the third imaging group 7 includes a first lens 7-1 with positive optical power, a second lens 7-2 with positive optical power, a third lens 7-3 with positive optical power, and a fourth lens 7-4 with negative optical power, which are sequentially arranged from the object side to the image side.

More specifically, the first lens 7-1 is a meniscus spherical silicon lens, the second lens 7-2 is a meniscus spherical silicon lens, the third lens 7-3 is a biconvex aspheric silicon lens, and the fourth lens 7-4 is a meniscus aspheric germanium lens, wherein concave surfaces of the first lens 7-1 and the fourth lens 7-4 face the image side, and concave surfaces of the second lens 7-2 face the object side.

The first lens 7-1 of the third imaging group 7 moves along the optical axis direction, so as to realize the drift compensation function of the image surface 10 under different working temperatures, the drift compensation function of the image surface 10 under different object distances and the non-uniform correction compensation function of the system, thereby realizing the working temperature in the range of-40 ℃ to +60 ℃, the image quality is good under the conditions that the imaging object distance ranges from 10 meters to infinity, the focal plane position is unchanged, and a uniform background is formed, so as to correct the non-uniformity of the system, compensate the working temperature, and perform focusing and non-uniform correction compensation for imaging at different distances.

Further, since the working frequency of the scanning galvanometer can reach 50-100 Hz when the scanning galvanometer is in the circumferential scanning working state, the size of the galvanometer is required to be small and the weight is light, in this embodiment, the exit pupil position of the lens group of the telescopic system is located near the azimuth scanning galvanometer 5, and the pitching scanning galvanometer 6 is located in a parallel light path between the lens group of the telescopic system and the third imaging group 7. In this way, the size of the azimuth scanning galvanometer 5, and the assembly error are reduced.

Further, in this embodiment, the azimuth scanning galvanometer 5 is disposed corresponding to the elevation scanning galvanometer 6, so that the beam incident from the object side is transmitted through the lens group of the telescopic system, and then projected to the azimuth scanning galvanometer 5, and the beam reflected by the azimuth scanning galvanometer 5 is reflected by the elevation scanning galvanometer 6, so that the beam reflected by the elevation scanning galvanometer 6 to the image side is parallel and opposite to the propagation path of the beam incident from the object side through the lens group of the telescopic system.

It will be appreciated that the light from infinity passes through the front group of lenses of the telescopic system and then emerges as parallel light, with its exit pupil positioned at the position of the azimuthal scanning galvanometer 5. The entrance pupil position of the area array scanning infrared optical system is positioned on the front surface of the first front fixed lens 1-1. The included angle between the azimuth scanning galvanometer 5 and the light path is 45 degrees, and the light path is turned by 90 degrees. The entrance pupil position of the third imaging group 7 coincides with the exit pupil position of the lens group of the telescopic system, and is located at the position of the azimuth scanning galvanometer 5, and is far away from the first lens 7-1 of the third imaging group 7, so as to place the pitching scanning galvanometer 6, the included angle between the pitching scanning galvanometer 6 and an optical path is 45 degrees, the optical path is turned by 90 degrees, and therefore finally, the light beam reflected to the image space by the pitching scanning galvanometer 6 and the propagation path of the light beam incident from the object space and passing through the lens group of the telescopic system are parallel and reverse.

Specifically, in this embodiment, the focal length of the area array scanning infrared optical system is f1, the length Jiao Jiaoju is f2, and the zoom ratio of the area array scanning infrared optical system is Γ, where Γ is 1 < Γ is less than or equal to 20. This enables a large zoom ratio of 20X.

It should be noted that the area array circumferential scanning search system includes the following steps:

step 1, designing the lens group of the telescopic system: determining a minimum field of view increase for a telescopic system that satisfies flyback compensation without vignetting or light blocking based on platform rotational speed _△ ωfov=ω×t×coses, ω is the platform rotation speed, t is the optical system area array detector integration time; obtaining the telescope systemThe total field of view of the system is ωfov=ωmax ++ωfov, ωmax is the maximum required field of view without scanning in the optical system;

step 2, determining a telescopic system multiplying power M with the smallest size of the azimuth scanning galvanometer 5 in the telescopic system according to the entrance pupil diameter and the structural size limitation of the telescopic system lens group;

step 3, according to the multiplying power M=f0 '/fe ' of the telescope system, the focal length F01 ' -F02 ' of the objective lens group and the focal length fe ' of the eyepiece lens group are determined by combining the F number of the system;

step 4, strictly matching the exit pupil position of the lens group of the telescopic system with the entrance pupil position of the third imaging group 7, and placing the scanning galvanometer 5 at the exit pupil position of the telescope, wherein the pitching scanning galvanometer 6 is placed in a middle parallel light path between the lens group of the telescopic system and the third imaging group 7;

step 5, matching and optimizing according to the lens group of the telescopic system and the tertiary imaging group 7 to obtain an area array scanning infrared optical system;

step 6: moving the first lens 7-1 of the tertiary imaging group 7 to completely defocus the image quality of the system to form a uniform background, thereby correcting the non-uniformity of the system;

step 7: the first lens 7-1 of the tertiary imaging group 7 is moved, so that the system can obtain higher imaging quality under the conditions of high temperature, low temperature and far and near focus, and the focusing stroke of the first lens 7-1 of the tertiary imaging group 7 is obtained.

Specifically, the image plane 10 may be understood as a surface of the photosensitive chip facing the object space, that is, may be a surface of an image pickup device such as a CCD or a CMOS, and it may be understood that light carrying subject information may sequentially pass through the front fixed lens group 1, the variable magnification lens group 2, the compensation lens group 3, the rear fixed lens group 4, the azimuth scanning galvanometer 5, the elevation scanning galvanometer 6, the tertiary imaging group 7, the optical window 8, the cold screen diaphragm 9, and finally be imaged on the image plane 10.

The data in the table is a group of data of the area array scanning infrared optical system, wherein the data comprises an area number, an area shape, a radius, a thickness and an optical material; the positive and negative of the radius meet the optical basic symbol rule; each set of data in the optical material represents the refractive index and abbe number of the material.

Further, in the present embodiment, the aspherical surface shape of the aspherical lens satisfies the following condition:

wherein Z represents the axial sagittal height of the aspheric surface in the Z direction; y represents the height of the aspherical surface; c represents the curvature of the fitting sphere, the numerical value is the inverse of the curvature radius, k is a conic coefficient, (the surface shape curve is a hyperbola when the k coefficient is smaller than-1, a parabola when the k coefficient is equal to-1, an ellipse when the k coefficient is between-1 and 0, a circle when the k coefficient is equal to 0, an oblate circle when the k coefficient is larger than 0), A, B, C, D, E, F is a higher order aspheric coefficient, and the shape and the size of the aspheric surfaces of the object side and the image side of the lens can be set through the parameters.

In this embodiment, please refer to fig. 2 and 3, which are schematic diagrams of the structure of the area array scanning infrared optical system at the wide-angle end and the telescopic end respectively.

Fig. 4 to 6 show MTF graphs of the area-scanning infrared optical system at the wide-angle end, the intermediate magnification, and the telephoto end, respectively.

From the above figures, it is clear that the MTF within each focal segment 1Field reaches 0.2 or more at 33lp/mm, and good imaging quality is achieved.

In summary, through the movement of the zoom lens group and the compensation lens group, and the back and forth retrace of the azimuth scanning galvanometer and the pitching scanning galvanometer, the multi-gear focal length two-dimensional area array scanning and the continuous zooming gaze tracking are realized. And under the high-magnification multi-gear focal length state, correcting off-axis aberration caused by the back swing of the azimuth scanning galvanometer and the pitching scanning galvanometer of the intermediate optical path, ensuring that the scanning galvanometer can clearly image in the whole two-dimensional space scanning process, ensuring accurate registration of images in the whole field of view in the multi-gear focal length state azimuth scanning process, and ensuring the stability of a pitching angle. The distortion value caused by the back swing of the azimuth scanning galvanometer and the pitching scanning galvanometer is controlled to be less than 0.5%, so that the accurate registration of images in the full view field range in the multi-gear focal length state scanning process is ensured, and the definition and stability of imaging are ensured. The system adopts a three-time imaging structure form, reduces the size of the lens of the front group, and reduces the volume and the weight of the area array scanning infrared optical system. And focusing the distance between the first lens of the three-time imaging group back and forth to realize working temperature compensation at-40 ℃ to +60 ℃, focusing of imaging at different distances and non-uniform correction compensation. The optical system has the advantages of large area array two-dimensional searching, tracking, large-multiplying power continuous zooming, wide working temperature range and clear imaging distance range, and can control the image shift compensation rate change under the condition of two-dimensional airspace searching so as to solve the image rotation problem of the image.

The working wave band of the area array scanning infrared optical system is 3.7-4.8 mu m, the F number of the area array scanning infrared optical system can reach 2-5.5, and the large zoom ratio of 20X can be realized.

The foregoing description is only of the preferred embodiments of the present utility model and is not intended to limit the scope of the utility model, and all equivalent structural changes made by the description of the present utility model and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the utility model.

Claims (10)

1. An area array scanning infrared optical system is characterized by comprising a lens group of a telescopic system, an azimuth scanning galvanometer, a pitching scanning galvanometer, a tertiary imaging group, an optical window, a cold screen diaphragm and an image plane which are sequentially arranged from an object space to an image space, wherein the cold screen diaphragm coincides with the exit pupil position of the tertiary imaging group;

the azimuth scanning galvanometer and the pitching scanning galvanometer are both in a fixed state and a reciprocating flyback state, and the pitching scanning galvanometer is used for compensating the image movement in the pitching direction while compensating the image movement in the horizontal direction.

2. The area array scanning infrared optical system as set forth in claim 1, wherein the lens group of the telescopic system comprises a front fixed lens group, a variable magnification lens group, a compensation lens group and a rear fixed lens group which are sequentially arranged from an object side to an image side, wherein the variable magnification lens group and the compensation lens group are movably arranged along an extending direction of an optical axis so as to realize continuous zooming of the area array scanning infrared optical system.

3. The area array scanning infrared optical system as set forth in claim 2, wherein the front fixed lens group includes a first front fixed lens and a second front fixed lens arranged in order from an object side to an image side;

the variable magnification lens group comprises a first variable magnification lens;

the compensating lens group comprises a first compensating lens and a second compensating lens which are sequentially arranged from an object space to an image space;

the rear fixed lens group comprises a first rear fixed lens, a second rear fixed lens and a third rear fixed lens with negative focal power, wherein the first rear fixed lens, the second rear fixed lens and the third rear fixed lens are sequentially arranged from an object space to an image space.

4. The area array scanning infrared optical system of claim 3, wherein the optical power of the first front fixed lens is positive and the optical power of the second front fixed lens is negative;

the focal power of the first variable-power lens is negative;

the focal power of the first compensation lens is positive, and the focal power of the second compensation lens is negative;

the focal power of the first rear fixed lens is negative, the focal power of the second rear fixed lens is positive, and the focal power of the third rear fixed lens is negative.

5. The area array scanning infrared optical system of claim 3, wherein the first front fixed lens is a meniscus silicon lens, the second front fixed lens is a meniscus germanium lens, and the concave surfaces of the first front fixed lens and the second front fixed lens face the image side;

the first zoom lens is a biconcave spherical silicon lens;

the first compensation lens is a biconvex aspheric silicon lens, the second compensation lens is a meniscus aspheric germanium lens, and the concave surface of the second compensation lens faces the object space;

the first rear fixed lens is a meniscus-type aspheric germanium lens, the concave surface of the first rear fixed lens faces to the object space, the second rear fixed lens is a biconvex aspheric silicon lens, and the third rear fixed lens is a biconcave aspheric germanium lens.

6. The area array scanning infrared optical system as set forth in claim 2, wherein the third imaging group includes a first lens having positive optical power, a second lens having positive optical power, a third lens having positive optical power, and a fourth lens having negative optical power, which are sequentially arranged from the object side to the image side.

7. The area array scanning infrared optical system of claim 6, wherein the first lens is a meniscus spherical silicon lens, the second lens is a meniscus spherical silicon lens, the third lens is a biconvex aspheric silicon lens, and the fourth lens is a meniscus aspheric germanium lens, wherein the concave surfaces of the first lens and the fourth lens are both facing the image space, and the concave surface of the second lens is facing the object space.

8. The area array scanning infrared optical system of claim 1, wherein an exit pupil position of the telescopic system lens group is located near the azimuthal scanning galvanometer;

the pitching scanning galvanometer is positioned in a parallel light path between the lens group of the telescopic system and the tertiary imaging group.

9. The area array scanning infrared optical system as set forth in claim 2, wherein the azimuth scanning galvanometer is disposed corresponding to the elevation scanning galvanometer so as to transmit the light beam incident from the object through the lens group of the telescopic system, and then project the light beam to the azimuth scanning galvanometer, and the light beam reflected by the azimuth scanning galvanometer is reflected by the elevation scanning galvanometer, so that the light beam reflected to the image space by the elevation scanning galvanometer is parallel and opposite to the propagation path of the light beam incident from the object through the lens group of the telescopic system.

10. The area scan infrared optical system of claim 1, wherein the area scan infrared optical system has a short focal length f1 and a long length Jiao Jiaoju f2, and the area scan infrared optical system has a zoom ratio Γ, wherein Γ is 1 < Γ is less than or equal to 20.