High-resolution medium-wave infrared continuous zoom lens

Abstract

The invention relates to an optical lens, in particular to a high-resolution medium-wave infrared continuous zoom lens, and aims to solve the problems that an existing medium-wave infrared continuous zoom lens is difficult to adapt to a medium-wave infrared detector with a small pixel size of 7.5 microns, and a tracked target is easily lost or target details cannot be distinguished. The zoom lens comprises a front fixed group lens, a zoom group lens, a compensation group lens and a rear fixed group lens which are sequentially arranged along the propagation direction of incident light, the zoom group lens and the compensation group lens can move along the optical axis direction; the front fixed group lens comprises a first lens; the zoom group lens comprises a second lens; the compensation group lens comprises a third lens; the rear fixed group lens comprises a fourth lens, a fifth lens, a sixth lens and a seventh lens; the focusing group lens can move along the optical axis direction according to the environment temperature and the shooting distance. Seven lenses are adopted, six-time zooming can be met, the system structure is compact, the light inlet amount is large, and the sensitivity is high.

Description

Technical Field

[0001] This invention relates to an optical lens, specifically a high-resolution mid-wave infrared continuous zoom lens. Background Technology

[0002] Infrared thermal imaging is a passive infrared night vision technology that detects and identifies targets based on temperature differences (thermal radiation differences) between the target and the background, or between different parts of the target. Due to its advantages such as being unaffected by day or night, strong smoke penetration, resistance to electromagnetic interference, anti-camouflage capabilities, and good detection concealment, infrared thermal imaging has gradually become a cutting-edge research focus. The mid-wave infrared cooling module is the core hardware carrier of infrared thermal imaging technology, typically including a mid-wave infrared detector, a miniature cooling system, and supporting data processing modules.

[0003] Currently, the main development trends for mid-wave infrared detectors in mid-wave infrared cooling mechanisms are large target areas, small pixel sizes, and high sensitivity. Mid-wave infrared cooling mechanisms equipped with 7.5μm small-pixel-size, high-sensitivity mid-wave infrared detectors are becoming increasingly mature. However, most existing mid-wave infrared continuous zoom lenses on the market are matched with 15μm pixel-size mid-wave infrared detectors, which have lower resolution. When matched with 7.5μm small-pixel-size mid-wave infrared detectors, it is difficult to achieve optimal imaging resolution, easily leading to problems such as target loss or inability to distinguish target details. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that existing mid-wave infrared continuous zoom lenses are difficult to adapt to mid-wave infrared detectors with a small pixel size of 7.5μm, which easily leads to the loss of tracking targets or the inability to distinguish target details, and to provide a high-resolution mid-wave infrared continuous zoom lens.

[0005] To achieve the above objectives, the technical solution provided by this invention is:

[0006] A high-resolution mid-wave infrared continuous zoom lens, which is special in that:

[0007] The system includes a front fixed lens group, a zoom lens group, a compensation lens group, a rear fixed lens group, and an adapter detector arranged sequentially along the incident light propagation direction. The zoom lens group and the compensation lens group are movable along the optical axis to achieve continuous zoom imaging. The front fixed lens group includes a first lens; the zoom lens group includes a second lens; the compensation lens group includes a third lens; the rear fixed lens group includes a fourth, fifth, sixth, and seventh lens arranged sequentially along the incident light propagation direction. The fifth, sixth, and seventh lenses form a focusing lens group, which can move along the optical axis according to ambient temperature and imaging distance to compensate for thermal differences throughout the focal length range and defocusing at different imaging distances. The first lens is a meniscus lens, with a convex first object-side surface and a concave first image-side surface. The fourth, fifth, sixth, and seventh lenses are arranged sequentially along the incident light propagation direction to achieve continuous zoom imaging. The second lens is a biconcave negative lens, with its object-side surface being the second concave object-side surface and its image-side surface being the second concave image-side surface; the third lens is a biconvex positive lens, with its object-side surface being the third convex object-side surface and its image-side surface being the third convex image-side surface; the fourth lens is a meniscus positive lens, with its object-side surface being the fourth convex object-side surface and its image-side surface being the fourth concave image-side surface; the fifth lens is a biconvex positive lens, with its object-side surface being the fifth convex object-side surface and its image-side surface being the fifth convex image-side surface; the sixth lens is a meniscus negative lens, with its object-side surface being the sixth convex object-side surface and its image-side surface being the sixth concave image-side surface; the seventh lens is a meniscus positive lens, with its object-side surface being the seventh convex object-side surface and its image-side surface being the seventh concave image-side surface; the second image-side surface, the third object-side surface, the fourth object-side surface, the fifth image-side surface, and the seventh object-side surface are all even-order aspherical surfaces; the second object-side surface is a diffraction surface.

[0008] Furthermore, the focal length f of the front fixed lens group, the zoom lens group, the compensation lens group, and the rear fixed lens group... A f B f C f D The following relationship must be satisfied:

[0009] 0.60≤f A / f L ≤0.75

[0010] -0.17≤f B / f L ≤-0.15

[0011] 0.19≤f C / f L ≤0.22

[0012] 0.18≤f D / f L ≤0.21

[0013] 0.35≤βBS / β BL ≤0.50

[0014] β BS ≤ -0.45

[0015] Where f L is the focal length value of the high - resolution mid - wave infrared continuous zoom lens in the longest focal length state;

[0016] β BS is the magnification of the zoom lens group in the short - focal length state;

[0017] β BL is the magnification of the zoom lens group in the long - focal length state.

[0018] Furthermore, the first object - side curvature radius RS1 of the first lens satisfies: 110.2 mm < RS1 < 115.0 mm, and the first image - side curvature radius RS2 of the first lens satisfies: 220 mm < RS2 < 228 mm; the second object - side curvature radius RS3 of the second lens satisfies: - 173.5 mm < RS3 < - 165.8 mm, and the second image - side curvature radius RS4 of the second lens satisfies: 117.0 mm < RS4 < 123.5 mm; the third object - side curvature radius RS5 of the third lens satisfies: 185.0 mm < RS5 < 192.3 mm, and the third image - side curvature radius RS6 of the third lens satisfies: - 183.5 mm < RS6 < - 179.2 mm; the fourth object - side curvature radius RS7 of the fourth lens satisfies: 12.5 mm < RS7 < 14.6 mm, and the fourth image - side curvature radius RS8 of the fourth lens satisfies: 8.5 mm < RS8 < 10.2 mm; the fifth object - side curvature radius RS9 of the fifth lens satisfies: 47.2 mm < RS9 < 52.0 mm, and the fifth image - side curvature radius RS 10 satisfies: - 105.4 mm < RS 10 < - 102.5 mm; the sixth object - side curvature radius RS 11 satisfies: 40.3 mm < RS 11 < 45.2 mm, and the sixth image - side curvature radius RS 12 satisfies: 19.3 mm < RS 12 < 21.6 mm; the seventh object - side curvature radius RS 13 satisfies: 23.5 mm < RS 13 < 26.3 mm, and the seventh image - side curvature radius RS 14 satisfies: 41.5 mm < RS 14 < 44.3 mm.

[0019] Furthermore, the aspherical coefficient a of the second image side surface (S4) of the second lens (B) 4(4) =-7.9161e-08, a 6(4) =4.4989e-10, a 8(4) =8.2340e-013, a 10(4) = -2.5366e-016; the aspherical coefficient a of the third object side surface (S5) of the third lens (C) 4(5) =-4.2294e-07, a 6(5) =1.9196e-11, a 8(5) =-2.2446e-013, a 10(5) =0; the aspherical coefficient a of the fourth object side (S7) of the fourth lens (D1) is 0. 4(7) =-1.7626e-06, a 6(7) =-3.2114e-08, a 8(7) =2.9383e-10, a 10(7) = -2.5116e-012; the aspherical coefficient a of the fifth image side surface (S10) of the fifth lens (D2) 4(10) =6.2258e-06, a 6(10) =4.4581e-09, a 8(10) =-2.4098e-012, a 10(10) = -1.1906e-015; the aspherical coefficient a of the seventh object side (S13) of the seventh lens (D4) 4(13) =-3.0878e-06, a 6(13) =1.2040e-09, a 8(13) =-1.0785e-011, a 10(13) =2.1670e-014; The diffraction order of the second object side (S3) of the second lens (B) is 1, the center wavelength is 4.2μm, and the phase coefficients of the diffraction surface are A1 = 0.00013 and A2 = -5.24566e-08.

[0020] Further, the air gap between the first lens and the second lens is 29.0 mm to 59.2 mm; the air gap between the second lens and the third lens is 55.0 mm to 4.0 mm; the air gap between the third lens and the fourth lens is 18.3 mm to 39.2 mm; the air gap between the fourth lens and the fifth lens is 32.4 mm to 34.6 mm; the air gap between the fifth lens and the sixth lens is 4.6 mm; and the air gap between the sixth lens and the seventh lens is 3.0 mm.

[0021] Furthermore, the first lens, the fourth lens, and the seventh lens are all made of single-crystal silicon; the second lens and the third lens are both made of germanium single crystal; the fifth lens is made of multispectral zinc sulfide; and the sixth lens is made of calcium fluoride crystal.

[0022] Furthermore, the adapted detector is a cooled mid-wave infrared focal plane detector.

[0023] Furthermore, the zoom lens group and the compensation lens group move towards each other when the high-resolution mid-wave infrared continuous zoom lens changes from a short focal length to a long focal length, and move away from each other when the high-resolution mid-wave infrared continuous zoom lens changes from a long focal length to a short focal length; the focusing lens group moves as follows: when the temperature changes from t to t', the fifth lens, the sixth lens, and the seventh lens all move towards the object side; when the temperature changes from t to t”, the fifth lens, the sixth lens, and the seventh lens all move towards the image side; wherein, t = 20℃, -40℃ ≤ t' < 20℃, 20℃ < t” ≤ 60℃.

[0024] Furthermore, the adapter detector has a resolution of 1280×1024 and a pixel size of 7.5μm.

[0025] Furthermore, the maximum outer envelope of the lens optical system is Φ75mm×179mm.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. The high-resolution mid-wave infrared continuous zoom lens provided by the present invention adopts a secondary imaging method, has seven lenses, and can meet the requirement of six times zoom by axial movement of the zoom group lens and the compensation group lens. The outer envelope size of the lens is ≤Φ75mm×179mm, which has the advantages of compact structure and small size.

[0028] 2. The high-resolution mid-wave infrared continuous zoom lens provided by this invention has an F-number of 2, meets 100% cold aperture matching, has a large light intake, good stray light suppression effect, and high sensitivity.

[0029] 3. The high-resolution mid-wave infrared continuous zoom lens provided by this invention is adapted to a detector with a resolution of 1280×1024 and a single pixel size of 7.5μm. The system transfer function curve MTF is close to the diffraction limit at the quist frequency of 66.7lp / mm inside the detector, and the full field-of-view distortion is <2.5% throughout the zoom range. The system has high resolution and excellent imaging quality.

[0030] 4. The high-resolution mid-wave infrared continuous zoom lens provided by this invention uses fewer lenses, has less stringent tolerance requirements in processing and assembly, is easier to manufacture. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of an embodiment of the high-resolution mid-wave infrared continuous zoom lens of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention in the short focal length state;

[0033] Figure 3 This is a schematic diagram of the structure of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention in a sub-short focal length state;

[0034] Figure 4 This is a schematic diagram of the structure of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention in the mid-focus state;

[0035] Figure 5 This is a schematic diagram of the structure of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention in the sub-telephoto state;

[0036] Figure 6 This is a schematic diagram of the structure of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention in the telephoto state;

[0037] Figure 7 The optical transfer function diagram of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention under normal temperature and short focal length conditions is shown.

[0038] Figure 8 This is a graph showing the optical transfer function of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention under normal temperature and sub-short focal length conditions.

[0039] Figure 9 This is a graph showing the optical transfer function of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention under normal temperature and mid-focus conditions.

[0040] Figure 10 This is a graph showing the optical transfer function of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention under normal temperature and sub-telephoto conditions.

[0041] Figure 11 The optical transfer function diagram of the high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention is shown under normal temperature and long focal length conditions.

[0042] Figure 12 This is a field curvature distortion diagram of an embodiment of the high-resolution mid-wave infrared continuous zoom lens of the present invention under normal temperature and short focal length conditions;

[0043] Figure 13 This is a field curvature distortion diagram of an embodiment of the high-resolution mid-wave infrared continuous zoom lens of the present invention under normal temperature and sub-short focal length conditions;

[0044] Figure 14 This is a field curvature distortion diagram of an embodiment of the high-resolution mid-wave infrared continuous zoom lens of the present invention under normal temperature and mid-focus conditions;

[0045] Figure 15 This is a field curvature distortion diagram of a high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention under normal temperature and sub-telephoto conditions;

[0046] Figure 16 This is a field curvature distortion diagram of a high-resolution mid-wave infrared continuous zoom lens embodiment of the present invention under normal temperature and long focal length conditions;

[0047] Explanation of reference numerals in the attached figures:

[0048] A - First lens, B - Second lens, C - Third lens, D1 - Fourth lens, D2 - Fifth lens, D3 - Sixth lens, D4 - Seventh lens, E - Adaptor detector;

[0049] S1 - Side view of the first object, S2 - Side view of the first image, S3 - Side view of the second object, S4 - Side view of the second image, S5 - Side view of the third object, S6 - Side view of the third image, S7 - Side view of the fourth object, S8 - Side view of the fourth image, S9 - Side view of the fifth object, S10 - Side view of the fifth image, S11 - Side view of the sixth object, S12 - Side view of the sixth image, S13 - Side view of the seventh object, S14 - Side view of the seventh image. Detailed Implementation

[0050] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0051] A high-resolution mid-wave infrared continuous zoom lens, see [link / reference] Figure 1 It includes a front fixed lens group, a zoom lens group, a compensation lens group, a rear fixed lens group, and an adapter detector E arranged sequentially along the incident light propagation direction; the front fixed lens group includes a first lens A; the zoom lens group includes a second lens B; the compensation lens group includes a third lens C; and the rear fixed lens group includes a fourth lens D1, a fifth lens D2, a sixth lens D3, and a seventh lens D4 arranged sequentially along the incident light propagation direction.

[0052] The first lens A is a meniscus positive lens, with its object-side surface being a convex first object-side surface S1 and its image-side surface being a concave first image-side surface S2; the second lens B is a biconcave negative lens, with its object-side surface being a concave second object-side surface S3 and its image-side surface being a concave second image-side surface S4; the third lens C is a biconvex positive lens, with its object-side surface being a convex third object-side surface S5 and its image-side surface being a convex third image-side surface S6; the fourth lens D1 is a meniscus positive lens, with its object-side surface being a convex fourth object-side surface S7 and its image-side surface being a concave fourth image-side surface S8; the fifth lens D2 is a biconvex positive lens. The object-side surface of the fifth object-side surface S9 is convex, and the image-side surface of the fifth image-side surface S10 is convex. The sixth lens D3 is a meniscus negative lens, with an object-side surface of the sixth object-side surface S11 being convex and an image-side surface of the sixth image-side surface S12 being concave. The seventh lens D4 is a meniscus positive lens, with an object-side surface of the seventh object-side surface S13 being convex and an image-side surface of the seventh image-side surface S14 being concave. The second image-side surface S4, the third object-side surface S5, the fourth object-side surface S7, the fifth image-side surface S10, and the seventh object-side surface S13 are all even-order aspherical surfaces. The second object-side surface S3 is a diffraction surface.

[0053] The fifth lens D2, the sixth lens D3 and the seventh lens D4 form the focusing group lens. The focusing group lens can move along the optical axis according to the ambient temperature and the shooting distance to compensate for thermal differences throughout the focal length range and defocusing at different shooting distances.

[0054] The zoom lens and compensation lens can move along the optical axis to achieve continuous zoom imaging; specifically, the zoom lens and compensation lens move towards each other when the high-resolution mid-wave infrared continuous zoom lens changes from a short focal length to a long focal length, and move away from each other when the high-resolution mid-wave infrared continuous zoom lens changes from a long focal length to a short focal length; the lens structure in short focal length, sub-short focal length, medium focal length, sub-long focal length, and long focal length states is described in [reference needed]. Figures 2-6 .

[0055] The focusing group lenses move as follows: when the temperature changes from t to t', the fifth lens D2, the sixth lens D3, and the seventh lens D4 all move towards the object side; when the temperature changes from t to t”, the fifth lens D2, the sixth lens D3, and the seventh lens D4 all move towards the image side; where t = 20℃, -40℃ ≤ t' < 20℃, and 20℃ < t” ≤ 60℃.

[0056] The parameters of each lens will be introduced next:

[0057] The focal length f of the front fixed lens group, zoom lens group, compensation lens group, and rear fixed lens group A f B f C f D The following relationship must be satisfied:

[0058] 0.60 ≤ f A / f L ≤ 0.75

[0059] -0.17 ≤ f B / f L ≤ -0.15

[0060] 0.19 ≤ f C / f L ≤ 0.22

[0061] 0.18 ≤ f D / f L ≤ 0.21

[0062] 0.35 ≤ β BS / β BL ≤ 0.50

[0063] β BS ≤ -0.45

[0064] Where f L is the focal length value of the high-resolution mid-wave infrared continuous zoom lens in the longest focal length state;

[0065] β BS is the magnification of the zoom lens group in the short focal length state;

[0066] β BL is the magnification of the zoom lens group in the long focal length state.

[0067] The radius of curvature RS1 of the first object side S1 of the first lens A satisfies: 110.2 mm < RS1 < 115.0 mm, and the radius of curvature RS2 of the first image side S2 of the first lens A satisfies: 220 mm < RS2 < 228 mm; the radius of curvature RS3 of the second object side S3 of the second lens B satisfies: -173.5 mm < RS3 < -165.8 mm, and the radius of curvature RS4 of the second image side S4 of the second lens B satisfies: 117.0 mm < RS4 < 123.5 mm; the radius of curvature RS5 of the third object side S5 of the third lens C satisfies: 185.0 mm < RS5 < 192.3 mm, and the radius of curvature RS6 of the third image side S6 of the third lens C satisfies: -183.5 mm < RS6 < -179.2 mm; the radius of curvature RS7 of the fourth object side S7 of the fourth lens D1 satisfies: 12.5 mm < RS7 < 14.6 mm, and the radius of curvature RS8 of the fourth image side S8 of the fourth lens D1 satisfies: 8.5 mm < RS8 < 10.2 mm; the radius of curvature RS9 of the fifth object side S9 of the fifth lens D2 satisfies: 47.2 mm < RS9 < 52.0 mm, and the radius of curvature RS 10 satisfies: -105.4 mm < RS 10<-102.5mm; Radius of curvature RS of the sixth object side surface S11 of the sixth lens D3 11 Meets the requirement of 40.3mm <RS 11 <45.2mm, the radius of curvature RS of the sixth image side surface S12 of the sixth lens D3. 12 Meets the requirement of 19.3mm <RS 12 <21.6mm; Radius of curvature RS of the seventh object side surface S13 of the seventh lens D4 13 Meets the requirement of 23.5mm <RS 13 <26.3mm, the radius of curvature RS of the seventh image side surface S14 of the seventh lens D4. 14 Meets the requirement of 41.5mm <RS 14 <44.3mm.

[0068] The data for each even-order aspheric surface are shown in Table 1:

[0069] Table 1

[0070]

[0071]

[0072] The expression for an even-order aspheric surface is:

[0073]

[0074] Where Z represents the position along the optical axis, r represents the height perpendicular to the optical axis, c represents the radius of curvature, K represents the conic coefficient, and a4, a6, a8, a 10 All are aspherical coefficients.

[0075] The data for the diffraction planes are shown in Table 2:

[0076] Table 2

[0077]

[0078] The equation of the diffraction surface is:

[0079]

[0080] in A1 represents the phase of the diffraction surface; Y represents the half-aperture of the lens perpendicular to the optical axis; A1 and A2 are both phase coefficients of the diffraction surface.

[0081] The air gap between the first lens A and the second lens B is 29.0 mm to 59.2 mm; the air gap between the second lens B and the third lens C is 55.0 mm to 4.0 mm; the air gap between the third lens C and the fourth lens D1 is 18.3 mm to 39.2 mm; the air gap between the fourth lens D1 and the fifth lens D2 is 32.4 mm to 34.6 mm; the air gap between the fifth lens D2 and the sixth lens D3 is 4.6 mm; and the air gap between the sixth lens D3 and the seventh lens D4 is 3.0 mm. The first lens A, the fourth lens D1, and the seventh lens D4 are all made of single-crystal silicon; the second lens B and the third lens C are both made of germanium single-crystal; the fifth lens D2 is made of multispectral zinc sulfide; and the sixth lens D3 is made of calcium fluoride crystal.

[0082] In this embodiment, the adapter detector E is a cooled mid-wave infrared focal plane detector with a resolution of 1280×1024 and a pixel size of 7.5μm. The maximum outer envelope of the lens optical system is Φ75mm×179mm.

[0083] Figures 7-16 The optical transfer function (MTF) and field curvature distortion (FCD) plots of the mid-wave infrared continuous zoom lens of this invention are shown at room temperature under short focal length, sub-short focal length, medium focal length, sub-long focal length, and long focal length conditions. In this embodiment, the MTF curve is close to the diffraction limit at the Nyquist frequency of 66.7 lp / mm for the compatible detector E, and the full field-of-view distortion is <2.5% throughout the zoom range. The system has high resolution and excellent imaging quality.

Claims

1. A high-resolution mid-wave infrared continuous zoom lens, characterized in that: It includes a front fixed group lens, a zoom group lens, a compensation group lens, a rear fixed group lens and an adapter detector (E) arranged in sequence along the incident light propagation direction; the zoom group lens and the compensation group lens can move along the optical axis direction to achieve continuous zoom imaging; The front fixed group lens includes a first lens (A); the zoom group lens includes a second lens (B); the compensation group lens includes a third lens (C); the rear fixed group lens includes a fourth lens (D1), a fifth lens (D2), a sixth lens (D3) and a seventh lens (D4) arranged in sequence along the incident light propagation direction; the fifth lens (D2), the sixth lens (D3) and the seventh lens (D4) form a focusing group lens, and the focusing group lens can move along the optical axis direction according to the ambient temperature and the shooting distance to compensate for the thermal difference within the entire focal length range and the defocus phenomenon at different shooting distances; The first lens (A) is a meniscus positive lens, its object side is the first object side (S1) with a convex surface, and its image side is the first image side (S2) with a concave surface; the second lens (B) is a double concave negative lens, its object side is the second object side (S3) with a concave surface, and its image side is the second image side (S4) with a concave surface; the third lens (C) is a double convex positive lens, its object side is the third object side (S5) with a convex surface, and its image side is the third image side (S6) with a convex surface; the fourth lens (D1) is a meniscus positive lens, its object side is the fourth object side (S7) with a convex surface, and its image side is the fourth image side (S8) with a concave surface; the fifth lens (D2) is a double convex positive lens, its object side is the fifth object side (S9) with a convex surface, and its image side is the fifth image side (S10) with a convex surface; the sixth lens (D3) is a meniscus negative lens, its object side is the sixth object side (S11) with a convex surface, and its image side is the sixth image side (S12) with a concave surface; the seventh lens (D4) is a meniscus positive lens, its object side is the seventh object side (S13) with a convex surface, and its image side is the seventh image side (S14) with a concave surface; the second image side (S4), the third object side (S5), the fourth object side (S7), the fifth image side (S10) and the seventh object side (S13) are all even aspherical surfaces; the second object side (S3) is a diffractive surface.

2. The high-resolution mid-wave infrared continuous zoom lens according to claim 1, characterized in that: The focal length f of the front fixed lens group, zoom lens group, compensation lens group, and rear fixed lens group. A f B f C f D The following relationship must be satisfied: 0.60≤f A / f L ≤0.75 -0.17≤f B / f L ≤-0.15 0.19≤f C / f L ≤0.22 0.18≤f D / f L ≤0.21 0.35≤β BS / β BL ≤0.50 β BS ≤-0.45 Among them, f L The focal length of the high-resolution mid-wave infrared continuous zoom lens at its longest focal length. β BS This represents the magnification of the zoom lens group in the short focal length state. β BL This represents the magnification of the zoom lens in telephoto mode.

3. The high-resolution mid-wave infrared continuous zoom lens according to claim 2, characterized in that: The curvature radius RS1 of the first object side (S1) of the first lens (A) satisfies: 110.2mm < RS1 < 115.0mm, and the curvature radius RS2 of the first image side (S2) of the first lens (A) satisfies: 220mm < RS2 < 228mm; The radius of curvature RS3 of the second object side S3 of the second lens (B) satisfies: -173.5 mm < RS3 < -165.8 mm, and the radius of curvature RS4 of the second image side S4 of the second lens (B) satisfies: 117.0 mm < RS4 < 123.5 mm; The radius of curvature RS5 of the third object side S5 of the third lens (C) satisfies: 185.0 mm < RS5 < 192.3 mm, and the radius of curvature RS6 of the third image side S6 of the third lens (C) satisfies: -183.5 mm < RS6 < -179.2 mm; The radius of curvature RS7 of the fourth object side S7 of the fourth lens (D1) satisfies: 12.5 mm < RS7 < 14.6 mm, and the radius of curvature RS8 of the fourth image side S8 of the fourth lens (D1) satisfies: 8.5 mm < RS8 < 10.2 mm; The radius of curvature RS9 of the fifth object side S9 of the fifth lens (D2) satisfies: 47.2 mm < RS9 < 52.0 mm, and the radius of curvature RS 10 of the fifth image side S10 of the fifth lens (D2) satisfies: -105.4 mm < RS 10 < -102.5 mm; The radius of curvature RS of the sixth object-side surface (S11) of the sixth lens (D3) 11 Meets the requirement of 40.3mm <RS 11 <45.2mm, radius of curvature RS of the sixth image side (S12) of the sixth lens (D3) 12 Meets the requirement of 19.3mm <RS 12 <21.6mm; The radius of curvature RS of the seventh object-side surface (S13) of the seventh lens (D4) 13 Meets the requirement of 23.5mm <RS 13 <26.3mm, radius of curvature RS of the seventh image side (S14) of the seventh lens (D4) 14 Meets the requirement of 41.5mm <RS 14 <44.3mm.

4. The high-resolution mid-wave infrared continuous zoom lens according to claim ३, wherein: The aspherical coefficient α of the second image side surface (S4) of the second lens (B) 4(4) =-7.9161e-08, a 6(4) =4.4989e-10, a 8(4) =8.2340e-013, a 10(4) = -2.5366e-016; The aspherical coefficient a of the third object side surface (S5) of the third lens (C) 4(5) =-4.2294e-07, a 6(5) =1.9196e-11, a 8(5) =-2.2446e-013, a 10(5) =0; The aspherical coefficient a of the fourth object side surface (S7) of the fourth lens (D1) 4(7) =-1.7626e-06, a 6(7) =-3.2114e-08, a 8(7) =2.9383e-10, a 10(7) = -2.5116e-012; The aspherical coefficient a of the fifth image side surface (S10) of the fifth lens (D2) 4(10) =6.2258e-06, a 6(10) =4.4581e-09, a 8(10) =-2.4098e-012, a 10(10) = -1.1906e-015; The aspherical coefficient a of the seventh object side (S13) of the seventh lens (D4) 4(13) =-3.0878e-06, a 6(13) =1.2040e-09, a 8(13) =-1.0785e-011, a 10(13) =2.1670e-014; The diffraction order of the second object side S3 of the second lens (B) is 1, the central wavelength is 4.2 μm, and the diffraction surface phase coefficients A1 = 0.00013 and A2 = -5.24566e-08.

5. The high-resolution mid-wave infrared continuous zoom lens according to claim ४, wherein: The air gap between the first lens (A) and the second lens (B) is 29.0 mm to 59.2 mm; The air gap between the second lens (B) and the third lens (C) is 55.0 mm to 4.0 mm; The air gap between the third lens (C) and the fourth lens (D1) is 18.3 mm to 39.2 mm; The air gap between the fourth lens (D1) and the fifth lens (D2) is 32.4 mm to 34.6 mm; The air gap between the fifth lens (D2) and the sixth lens (D3) is 4.6 mm; The air gap between the sixth lens (D3) and the seventh lens (D4) is 3.0 mm.

6. The high-resolution mid-wave infrared continuous zoom lens according to claim ५, wherein: The materials of the first lens (A), the fourth lens (D1), and the seventh lens (D4) are all single-crystalline silicon; The materials of the second lens (B) and the third lens (C) are both germanium single crystals; The material of the fifth lens (D2) is multi-spectral zinc sulfide; The material of the sixth lens (D3) is calcium fluoride crystal.

7. The high-resolution mid-wave infrared continuous zoom lens according to claim ६, wherein: The adapted detector (E) is a cooled mid-wave infrared focal plane detector.

8. The high-resolution mid-wave infrared continuous zoom lens according to claim ७, wherein: The zoom lens group and the compensation lens group move towards each other when changing from the short focal state to the long focal state, and move away from each other when changing from the long focal state to the short focal state; The focusing group lenses move as follows: when the temperature changes from t to t', the fifth lens (D2), the sixth lens (D3), and the seventh lens (D4) all move towards the object side; when the temperature changes from t to t”, the fifth lens (D2), the sixth lens (D3), and the seventh lens (D4) all move towards the image side. Where t=20℃, -40℃≤t'<20℃, 20℃<t”≤60℃.

9. The high-resolution mid-wave infrared continuous zoom lens according to claim 8, characterized in that: The adapter detector (E) has a resolution of 1280×1024 and a pixel size of 7.5μm.

10. The high-resolution mid-wave infrared continuous zoom lens according to any one of claims 1 to 9, characterized in that: The maximum outer envelope of the lens optical system is Φ75mm×179mm.

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