Turning type miniaturized long-wave infrared continuous zooming optical system

Abstract

The invention relates to a turning type miniaturized long-wave infrared continuous zooming optical system which is composed of a first meniscus positive lens, a biconcave negative lens, a biconvex positive lens, a second meniscus positive lens, a meniscus negative lens, a plane turning reflector and a third meniscus positive lens which are sequentially arranged from the object space to the image space. According to the optical system, continuous zooming of 30mm-150mm is realized through reasonable distribution of focal power of each lens, a motion curve is smooth, continuous and free of inflection points in the zooming process, a reflecting mirror is introduced into an imaging light path, and an L-shaped optical structure form is formed after the reflection of the reflecting mirror, so that the length of the optical system is effectively shortened, and the imaging efficiency is improved. And the miniaturization design of the whole system structure can be realized.

Description

Technical Field

[0001] The invention relates to the field of infrared optical systems, and in particular to a turning-type miniaturized long-wave infrared continuous zoom optical system. Background Art

[0002] Infrared thermal imaging systems have been widely used in both military and civilian fields due to their strong anti-interference ability, long range, and all-weather and all-day operation. In the military, they can realize the search, reconnaissance, identification and tracking of military targets, precise guidance of infrared imaging, and driving and navigation of weapon platforms. In the civilian field, infrared imaging technology has become the most effective detection tool in the field of preventive maintenance. It can quickly and accurately detect faults before equipment fails. It is also widely used in many fields such as industry, remote sensing, medicine, power equipment detection and scientific research.

[0003] The optoelectronic system used for target search and identification requires that the infrared thermal imaging system should be able to realize both target search with a large field of view and identification of distant targets with a small field of view. Therefore, a single-field-of-view infrared optical system cannot meet this requirement. The optical system of the infrared thermal imager needs to be designed as a zoom optical system to achieve this function. The continuous zoom infrared optical system has a wide coverage rate with a short focal length and a large field of view, and a high resolution with a long focal length and a small field of view. A large field of view can be used to search for targets over a large range, and a small field of view can be used to identify targets. During the zoom process, the target image can always remain clear, and the field of view can be transformed into any field within the zoom range. The tracking target will not be lost during the continuous zoom process, and the appropriate working field of view can be selected according to the scene and target characteristics, greatly improving the human-machine efficiency.

[0004] In order to improve the temperature sensitivity of the uncooled infrared continuous zoom optical system, that is, to reduce the minimum resolvable temperature difference of the system, it is necessary to reduce the F# of the system and improve the transmittance and transfer function of the optical system. When designing the optical system, the aperture of the system should be increased as much as possible, which makes the aperture of the uncooled infrared continuous zoom optical system larger and longer. For infrared optical systems installed in spherical space, the total length needs to be controlled. An optical system with a short total length is conducive to the miniaturization design of the overall system.

[0005] Chinese patent application No. 201520063577.7 discloses a continuous zoom uncooled telephoto thermal imaging lens. The focal length of the telephoto end of the zoom optical system is 150 mm, and the total length of the optical system is 244 mm.

[0006] Chinese patent application No. 201510415786.8 discloses a continuous zoom uncooled infrared thermal imager, the focal length of the zoom optical system is 30 to 150 mm, and the total length of the optical system is 286.88 mm.

[0007] The Chinese patent application with application number 201921561612.2 discloses a 5x long-wave infrared continuous zoom lens. The focal length of the zoom optical system at the telephoto end is 150mm, and the resolution of the adapted detector is 640×512, 17μm×17μm. According to the public parameters, the length of the lens is 194.54mm, excluding the distance from the last lens to the imaging surface.

[0008] The Chinese patent application with application number 201821510740.X discloses a portable, long-focal-length, economical, long-wave infrared continuous lens, the effective focal length EFL of which is 30-150 mm, the F number is 1.15@f150 mm, the F number is 0.81@f30 mm, the total length of the optical system is 235 mm, the detector resolution is 640×480, and the pixel size is 17 μm.

[0009] The Chinese patent application with application number 202123050114.1 discloses an infrared continuous zoom lens with a magnification of 5 times, an effective focal length of 30 to 150 mm, a field of view angle range of 5.2° to 26.8°, an adapted detector resolution of 640×512, 17μm×17μm, and a total length of the optical system of 222.98 mm. Summary of the invention

[0010] In order to solve the technical problem that the current continuous zoom long-wave infrared lens is too long, the present invention provides a turning type miniaturized long-wave infrared continuous zoom optical system.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is:

[0012] A turning type miniaturized long-wave infrared continuous zoom optical system, the optical system consists of a first meniscus positive lens, a double concave negative lens, a double convex positive lens, a second meniscus positive lens, a meniscus negative lens, a plane turning reflector, and a third meniscus positive lens, which are arranged in sequence on the same optical axis from the object side to the image side. The angle between the normal of the plane turning reflector and the optical axis is 45°. The plane turning reflector makes the angle between the outgoing light of the meniscus negative lens and the incident light of the third meniscus positive lens 90°. The focal length of the optical system is changed by axially moving the double concave negative lens and the double convex positive lens.

[0013] Furthermore, the concave surfaces of the first meniscus positive lens, the second meniscus positive lens, and the meniscus negative lens are all arranged toward the reflecting surface of the plane turning reflector, and the concave surface of the third meniscus positive lens is arranged away from the reflecting surface of the plane turning reflector.

[0014] Furthermore, when the focal length of the system changes from short focus to long focus, the biconcave negative lens moves axially away from the first meniscus positive lens, and the biconvex positive lens moves axially towards the first meniscus positive lens.

[0015] Furthermore, the center distance between the double concave negative lens and the first meniscus positive lens is 12.21-49.38 mm, the center distance between the double convex positive lens and the second meniscus positive lens is 5.5-43.63, and in the process of changing from a large field of view to a small field of view, the stroke of the double concave negative lens is 37.17 mm, and the stroke of the double convex positive lens is 38.13 mm.

[0016] Furthermore, the optical system uses a method of axially moving the third meniscus positive lens to compensate for defocus caused by changes in object distance or temperature.

[0017] Furthermore, the materials of the first meniscus positive lens, the double concave negative lens, the double convex positive lens, the second meniscus positive lens, the meniscus negative lens and the third meniscus positive lens are all single crystal germanium Ge, and the material of the plane turning reflector is quartz.

[0018] Furthermore, the first meniscus positive lens satisfies the following condition: 0.7≤f1 / f≤0.9, where f is the focal length of the optical system in a telephoto state, and f1 is the effective focal length of the first meniscus positive lens;

[0019] The biconcave negative lens satisfies the following condition: -0.3≤f2 / f≤-0.2, where f is the focal length of the optical system in the telephoto state, and f2 is the full effective focal length of the biconcave negative lens;

[0020] The biconvex positive lens satisfies the following condition: 0.2≤f3 / f≤0.4, where f is the focal length of the optical system in the telephoto state, and f3 is the effective focal length of the biconvex positive lens;

[0021] The second meniscus positive lens satisfies the following condition: 0.6≤f4 / f≤0.7, where f is the focal length of the optical system in a telephoto state, and f4 is the effective focal length of the second meniscus positive lens;

[0022] The meniscus negative lens satisfies the following condition: -0.3≤f5 / f≤-0.2, where f is the focal length of the optical system in a telephoto state, and f5 is the effective focal length of the meniscus negative lens;

[0023] The third meniscus positive lens satisfies the following condition: 0.2≤f6 / f≤0.3, where f is the focal length of the optical system in a telephoto state, and f6 is the effective focal length of the third meniscus positive lens;

[0024] Furthermore, a surface S3 of the biconcave negative lens facing the object, a surface S7 of the second meniscus positive lens facing the object, and a surface S11 of the third meniscus positive lens facing the folding reflector are all aspherical surfaces.

[0025] Furthermore, a surface S9 of the meniscus negative lens facing the object side is a diffractive aspheric surface.

[0026] Furthermore, the technical parameters of the optical system are as follows: working band: 8μm~12μm; F # : 1.2; focal length: 30mm~150mm; field of view: 14.6°×11.7°~2.93°×2.35°; adapted to 640×512, 12μm long-wave infrared detector; among which, F # The calculation formula is f / D, where f is the focal length of the optical system and D is the diameter of the entrance pupil.

[0027] Beneficial effects:

[0028] 1. The optical system of the present invention adopts a mechanical positive group compensation group zoom form, and realizes 30mm-150mm continuous zoom through the reasonable distribution of the optical power of each lens. By introducing a reflector in the imaging light path, an "L"-shaped optical structure is formed after the reflector is folded, which effectively shortens the length of the optical system. The size of the optical system is 190mm (length) × 138mm (width) × 138mm (height), which is conducive to the miniaturization design of the overall structure of the system.

[0029] 2. The motion curve of the optical system of the present invention is smooth and continuous during the zooming process without any inflection point, thereby ensuring clear imaging throughout the zooming process without any jamming. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Light path diagram of the optical system of the present invention when in a short-focus state of 30 mm;

[0031] Figure 2 Light path diagram of the optical system of the present invention when in the mid-focus state of 90mm;

[0032] Figure 3 Light path diagram of the optical system of the present invention when in telephoto 150mm state;

[0033] Figure 4 The transfer function diagram of the optical system of the present invention when in the short-focus 30mm state;

[0034] Figure 5 The transfer function diagram of the optical system of the present invention when in the mid-focus state of 90mm;

[0035] Figure 6The transfer function diagram of the optical system of the present invention when in the telephoto state of 150mm;

[0036] Figure 7 The spot diagram of the optical system of the present invention when in the short-focus 30mm state;

[0037] Figure 8 The spot diagram of the optical system of the present invention when in the middle focal length 90mm state;

[0038] Fig. 9 The spot diagram of the optical system of the present invention when in the telephoto 150mm state;

[0039] Fig.10 Field curvature and distortion curves of the optical system of the present invention when in a short-focus state of 30 mm;

[0040] Fig.11 Field curvature and distortion curves of the optical system of the present invention when in the mid-focus state of 90mm;

[0041] Fig.12 Field curvature and distortion curves of the optical system of the present invention when in a telephoto state of 150mm;

[0042] Fig.13 Zoom curve diagram of the optical system of the present invention.

[0043] Among them, 1 is the first meniscus positive lens, 2 is the double concave negative lens, 3 is the double convex positive lens, 4 is the second meniscus positive lens, 5 is the meniscus negative lens, 6 is the plane reflector, 7 is the third meniscus positive lens, and 8 is the image plane. DETAILED DESCRIPTION

[0044] In order to make the above features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right" and the like indicating directions or positional relationships, they are only corresponding to the drawings of the present application for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific direction.

[0045] In addition, the terms "first", "second" and "third" are used for descriptive purposes only and refer to the order in which lenses of this type appear. They are distinguished in the description and have no special meanings and cannot be understood as indicating or implying relative importance.

[0046] Throughout the specification, like reference numerals refer to like elements.In the drawings, the figures are by way of example only and are not drawn strictly to scale.

[0047] As common sense, the direction close to the object space is the object side, and the direction close to the image space is the image side. From the object side to the image side, the two sides of the lens are the incident side and the exit side. The object side refers to the side where the light enters, and the image side refers to the side where the light exits. "From the object side to the image side along the optical axis" is like Figure 1 The direction from left to right in the image. The surface facing the object side of the two surfaces of each lens is called the object side surface, and the surface facing the image side of the two surfaces of each lens is called the image side surface.

[0048] like Figure 1 to Figure 3 The illustrated indicative miniaturized long-wave infrared continuous zoom optical system is composed of a first meniscus positive lens 1, a double concave negative lens 2, a double convex positive lens 3, a second meniscus positive lens 4, a meniscus negative lens 5, a plane turning reflector 6, and a third meniscus positive lens 7, which are arranged in sequence from the object side to the image side.

[0049] The first meniscus positive lens 1, the double concave negative lens 2, the double convex positive lens 3, the second meniscus positive lens 4, the meniscus negative lens 5, the plane turning reflector 6, and the third meniscus positive lens 7 are arranged in sequence on the same optical axis. The plane turning reflector 6 is arranged between the meniscus negative lens 5 and the third meniscus positive lens 7. The angle between the normal of the plane turning reflector 6 and the optical axis is 45°. The angle between the outgoing light of the meniscus negative lens 5 and the incident light of the third meniscus positive lens 7 is 90° through the plane turning reflector.

[0050] The concave surfaces of the first meniscus positive lens 1 , the second meniscus positive lens 4 , and the meniscus negative lens 5 are all arranged toward the plane turning reflector 6 , and the concave surface of the third meniscus positive lens 7 is arranged away from the plane turning reflector 6 .

[0051] Further, such as Figures 1 to 3 As shown, the focal length of the optical system is changed by axially moving the biconcave negative lens 2 and the biconvex positive lens 3. When the focal length changes from short focus to long focus, the biconcave negative lens 2 moves axially in a direction away from the first meniscus positive lens 1, and the biconvex positive lens 3 moves axially in a direction close to the first meniscus positive lens 1. When the distance between the biconcave negative lens 2 and the first meniscus positive lens 1 is the shortest, and the distance between the biconvex positive lens 3 and the second meniscus positive lens 4 is the shortest, it is a large field of view state, and the optical system is in a state of the shortest focal length of 30mm; when the distance between the biconcave negative lens 2 and the first meniscus positive lens 1 is the farthest, and the distance between the biconvex positive lens 3 and the second meniscus positive lens 4 is the farthest, it is a small field of view state, and the optical system is in a state of the longest focal length of 150mm.

[0052] The center distance between the double concave negative lens 2 and the first meniscus positive lens 1 is 12.21-49.38 mm, and the center distance between the double convex positive lens 3 and the second meniscus positive lens 4 is 5.5-43.63. In the process of changing from a large field of view to a small field of view, the stroke of the double concave negative lens 2 is 37.17 mm, and the stroke of the double convex positive lens 3 is 38.13 mm.

[0053] The optical system uses the method of axially moving the third meniscus positive lens 7 to achieve image plane defocus compensation within the temperature range of -40°C to +60°C and system defocus compensation caused by changes in the distance of the observed scene, thereby ensuring clear imaging of objects at different distances.

[0054] Preferably, the materials of the first meniscus positive lens 1, the biconcave negative lens 2, the biconvex positive lens 3, the second meniscus positive lens 4, the meniscus negative lens 5, and the third meniscus positive lens 7 are all single crystal germanium (Ge), and the material of the plane turning reflector 6 is quartz.

[0055] The specific light transmission path of the above-mentioned optical system is as follows: the light emitted by the infrared radiation of the external scene is converged by the first meniscus positive lens 1 and reaches the biconcave negative lens 2, diverged by the biconcave negative lens 2 and reaches the biconvex positive lens 3, converged by the biconvex positive lens 3 and reaches the second meniscus positive lens 4, converged by the second meniscus positive lens 4 and reaches the meniscus negative lens 5, diverged by the meniscus negative lens 5 and reaches the plane turning reflector 6, reflected by the plane turning reflector 6 and reaches the third meniscus positive lens 7, and is imaged on the image plane 8 after being converged by the third meniscus positive lens 7.

[0056] Preferably, the first meniscus positive lens 1 satisfies the following condition: 0.7≤f1 / f≤0.9, where f is the focal length of the optical system in a telephoto state, and f1 is the effective focal length of the first meniscus positive lens;

[0057] The biconcave negative lens 2 satisfies the following condition: -0.3≤f2 / f≤-0.2, where f is the focal length of the optical system in the telephoto state, and f2 is the full effective focal length of the biconcave negative lens;

[0058] The biconvex positive lens 3 satisfies the following condition: 0.2≤f3 / f≤0.4, where f is the focal length of the optical system in the telephoto state, and f3 is the effective focal length of the biconvex positive lens;

[0059] The second meniscus positive lens 4 satisfies the following condition: 0.6≤f4 / f≤0.7, where f is the focal length of the optical system in a telephoto state, and f4 is the effective focal length of the second meniscus positive lens;

[0060] The meniscus negative lens 5 satisfies the following condition: -0.3≤f5 / f≤-0.2, where f is the focal length of the optical system in the telephoto state, and f5 is the effective focal length of the meniscus negative lens;

[0061] The third meniscus positive lens 7 satisfies the following condition: 0.2≤f6 / f≤0.3, where f is the focal length of the optical system in a telephoto state, and f6 is the effective focal length of the third meniscus positive lens;

[0062] The technical indicators achieved by the present invention are shown in Table 1, where F # The calculation formula of (optical system F number) is f / D, where f is the focal length of the optical system and D is the diameter of the entrance pupil. Table 1 Technical indicators of the optical system of the present invention parameter Technical indicators detector 640×512 long wave infrared detector Pixel size 12μm Working band 8μm~12μm <![CDATA[F # (Optical System F Number)]]> 1.2 focal length 30mm~150mm Field of view 14.6°×11.7°～2.93°×2.35°

[0063] Table 2 lists the detailed data of the embodiment of the optical system of the present invention when the focal length is 30mm to 150mm, which includes the surface type, radius of curvature, thickness and material of each lens. Among them, the units of the radius of curvature and thickness of the lens are mm, and the radius of curvature of the spherical surface and the aspherical surface refers to the radius of curvature at the intersection of the lens surface and the optical axis. Among them, the "surface serial number" in Table 2 is counted along the direction of light propagation, such as the light beam incident surface of the first meniscus positive lens 1 is serial number S1, the light beam exit surface is serial number S2, and the serial numbers of other mirror surfaces are deduced by analogy; the "radius" in Table 2 represents the radius of curvature of the surface, and its positive and negative determination principle is: the intersection of the surface and the main optical axis is taken as the starting point, and the center of the curved surface of the surface is taken as the end point. If the connecting line direction is the same as the light propagation direction, it is positive, otherwise it is negative. If the surface is a plane, the radius of curvature of the surface is infinite; the "thickness" in Table 2 gives the distance between two adjacent surfaces on the optical axis, and its positive and negative determination principle is: take the vertex of the current surface as the starting point, and the vertex of the next surface as the end point. If the direction of the line is the same as the direction of light propagation, it is positive, otherwise it is negative. If the material between the two surfaces is infrared material, the thickness represents the lens thickness. If there is no material between the two surfaces, it represents the air space between the two lenses. Table 2 Detailed data of the optical system of the embodiment of the present invention

[0064] The inflection type miniaturized long-wave infrared continuous zoom optical system, the first meniscus positive lens 1, the biconcave negative lens 2, the biconvex positive lens 3, the second meniscus positive lens 4, the meniscus negative lens 5, the third meniscus positive lens 7, the curved surfaces along the object to image direction are marked as S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12 respectively; wherein, the surface S3 of the biconcave negative lens 2 facing the object side, the surface S7 of the second meniscus positive lens 4 facing the object side, and the surface S11 of the third meniscus positive lens 7 facing the folding reflector side are all aspherical surfaces.

[0065] Furthermore, the surface equations of the above-mentioned aspheric surfaces are:

[0066]

[0067] Among them, z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis, c is the curvature, c=1 / R, R represents the radius of curvature of the lens surface, r is the radial coordinate in the direction perpendicular to the optical axis, k is the quadratic curve constant, A is the fourth-order aspheric coefficient, B is the sixth-order aspheric coefficient, and C is the eighth-order aspheric coefficient.

[0068] Table 3 lists the aspheric coefficients of the surface S3 of the double concave negative lens 2 facing the object side, the surface S7 of the second meniscus positive lens 4 facing the object side, and the surface S11 of the third meniscus positive lens 7 facing the folding reflector side according to the present invention. The table uses scientific notation. For example, -2.398381e-007 represents -2.398381×10 -7 . Table 3 Aspheric coefficients of the present invention

[0069] Furthermore, the surface S9 of the meniscus negative lens 5 facing the object side is an aspherical surface, and a continuous relief structure is formed on the aspherical substrate by diamond turning to form a diffraction surface, which satisfies the equation:

[0070] Among them, z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis, c is the curvature, c=1 / R, R represents the radius of curvature of the lens surface, r is the radial coordinate in the direction perpendicular to the optical axis, k is the quadratic curve constant, A is the fourth-order aspheric coefficient, B is the sixth-order aspheric coefficient, and C is the eighth-order aspheric coefficient; HOR is the diffraction order, C1, C2, and C3 are the diffraction surface coefficients, λ0 is the design center wavelength; n is the refractive index of the lens, and n0 is the refractive index of air.

[0071] Table 4 lists the diffraction aspheric coefficients of the surface S9 of the meniscus negative lens 5 facing the object side according to the present invention. Table 4 Diffraction aspheric coefficients of the present invention

[0072] According to the above optical system, after simulation by optical design software, such as Figure 4 , Figure 5 , Figure 6 As shown, in the short-focus, medium-focus and long-focus states, at the characteristic frequency of 42lp / mm corresponding to the detector, the transfer function in the full field of view is greater than 0.3; Figure 7 , Figure 8 , Fig. 9 As shown in the spot diagrams at short, medium and long focal lengths, the diffuse spot diameter of the system is equivalent to the detector pixel size; Fig.10 , Fig.11 , Fig.12 As shown in FIG. 1 , the field curvature and distortion curves in the short-focus, medium-focus and long-focus states, the distortion of the system in the short-focus state is less than 2%, and the distortion in the long-focus state is less than 0.1%; Fig.13 As shown in FIG. 1 , it is a zoom curve diagram of the continuous zoom optical system, the horizontal axis is the focal length of the continuous zoom optical system, and the vertical axis is the axial movement distance of the zoom group and the compensation group. As can be seen from the figure, the zoom curve of the system is smooth and continuous, without any mutation points, which can effectively avoid the system from getting stuck during the zoom process.

[0073] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above in preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A miniaturized long-wave infrared continuous zoom optical system, characterized in that: The optical system comprises a first meniscus positive lens (1), a double concave negative lens (2), a double convex positive lens (3), a second meniscus positive lens (4), a meniscus negative lens (5), a plane folding reflector (6), and a third meniscus positive lens (7), which are arranged in sequence on the same optical axis from the object side to the image side. The angle between the normal of the plane folding reflector (6) and the optical axis is 45°. The angle between the outgoing light of the meniscus negative lens (5) and the incident light of the third meniscus positive lens (7) is 90° through the plane folding reflector. The focal length of the optical system is changed by axially moving the double concave negative lens (2) and the double convex positive lens (3).

2. The miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: The concave surfaces of the first meniscus positive lens (1), the second meniscus positive lens (4) and the meniscus negative lens (5) are all arranged toward the reflecting surface of the plane turning reflector (6), and the concave surface of the third meniscus positive lens (7) is arranged away from the reflecting surface of the plane turning reflector (6).

3. The inflection type miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: When the focal length of the system changes from short focal length to long focal length, the biconcave negative lens (2) moves axially in a direction away from the first meniscus positive lens (1), and the biconvex positive lens (3) moves axially in a direction approaching the first meniscus positive lens (1).

4. The inflection type miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: The center distance between the biconcave negative lens (2) and the first meniscus positive lens (1) is 12.21-49.38 mm, and the center distance between the biconvex positive lens (3) and the second meniscus positive lens (4) is 5.5-43.

63. In the process of changing from a large field of view to a small field of view, the travel of the biconcave negative lens (2) is 37.17 mm, and the travel of the biconvex positive lens (3) is 38.13 mm.

5. The inflection type miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: The optical system adopts the method of axially moving the third meniscus positive lens (7) to achieve compensation for defocus caused by changes in object distance or temperature.

6. The inflection type miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: The materials of the first meniscus positive lens (1), the double concave negative lens (2), the double convex positive lens (3), the second meniscus positive lens (4), the meniscus negative lens (5) and the third meniscus positive lens (7) are all single crystal germanium Ge, and the material of the plane turning reflector (6) is quartz.

7. The inflection type miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: The focal length of each lens of the optical system must meet the following conditions: 0.7≤ f 1 / f ≤0.9，-0.3≤ f 2 / f ≤-0.2，0.2≤ f 3 / f ≤0.4，0.6≤ f 4 / f ≤0.7，-0.3≤ f 5 / f ≤-0.2，0.2≤ f 6 / f ≤0.3； in: f is the focal length of the optical system; f 1 is the effective focal length of the first meniscus positive lens (1); f 2 is the full effective focal length of the biconcave negative lens (2); f 3 is the effective focal length of the biconvex positive lens (3); f 4 is the effective focal length of the second meniscus positive lens (4); f 5 is the effective focal length of the meniscus negative lens (5); f 6 is the effective focal length of the third meniscus positive lens (7).

8. The inflection type miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: A surface S3 of the double concave negative lens (2) facing the object side, a surface S7 of the second meniscus positive lens (4) facing the object side, and a surface S11 of the third meniscus positive lens (7) facing the folding reflector side are all aspherical surfaces.

9. The inflection type miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: The surface S9 of the meniscus negative lens (5) facing the object side is a diffractive aspheric surface.

10. The inflection type miniaturized long-wave infrared continuous zoom optical system according to claim 1, characterized in that: The technical parameters achieved by the optical system are as follows: working band: 8μm~12μm; F # : 1.2; focal length: 30mm~150mm; field of view: 14.6°x11.7°~2.93°x2.35°; adapted to 640x512, 12μm long-wave infrared detector; among which, F # The calculation formula is f / D , f is the focal length of the optical system, D is the entrance pupil diameter.

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