Short wave infrared continuous zoom optical system

Abstract

The application discloses a short-wave infrared continuous zoom optical system, which comprises, from the object side to the image side, a front fixed group with positive refractive power, a zoom group with negative refractive power, a compensation group with negative refractive power, an aperture diaphragm, a rear fixed group with positive refractive power and a focusing group with positive refractive power; the front fixed group comprises, from the object side to the image side, a first negative meniscus negative lens, a first biconvex positive lens and a first positive meniscus positive lens; the zoom group comprises, from the object side to the image side, a first biconcave negative lens and a second positive meniscus positive lens; the compensation group is a first doublet lens with negative refractive power; the rear fixed group comprises, from the object side to the image side, a second biconvex positive lens and a second negative meniscus negative lens; the focusing group is a third positive meniscus positive lens; the focusing group can move forward and backward along the optical axis direction to compensate for the thermal difference of the optical system; the zoom group and the compensation group move forward and backward along the optical axis direction to realize continuous zoom imaging of the optical system.

Description

Technical Field

[0001] This application relates to the field of optical lens technology, and in particular to a short-wave infrared continuous zoom optical system. Background Technology

[0002] Short-wave infrared imaging (0.9–1.7 μm) is mainly based on the principle of target reflected light imaging. This imaging method, which is similar to visible light, makes short-wave infrared imaging highly contrastive, able to penetrate glass, less affected by atmospheric scattering, and has strong penetration capabilities for fog and smoke. It is currently widely used in machine vision, industrial inspection, quality control and other fields.

[0003] Continuous zoom optical systems with temperature adaptability can be flexibly applied to shooting needs in different scenarios, exhibiting strong versatility. Systems with low distortion and high contrast can obtain more realistic, accurate, and clear high-quality images. Existing short-wave infrared continuous zoom systems, while achieving long focal lengths, do not address the requirement of low distortion. Therefore, it is necessary to develop and design a short-wave infrared optical system with high contrast, low distortion, and temperature adaptability. Summary of the Invention

[0004] In view of this, the present application provides a short-wave infrared continuous zoom optical system to at least solve the above-mentioned technical problems existing in the prior art.

[0005] According to a first aspect of this application, embodiments of this application provide a short-wave infrared continuous zoom optical system, comprising:

[0006] The optical system is arranged sequentially from object to image: a front fixed group with positive optical power, a zoom group with negative optical power, a compensation group with negative optical power, an aperture stop, a rear fixed group with positive optical power, and a focusing group with positive optical power. The front fixed group consists of three lenses: a first negative meniscus lens, a first biconvex positive lens, and a first positive meniscus lens, arranged sequentially from object to image. The zoom group consists of two lenses: a first biconcave negative lens and a second positive meniscus lens, arranged sequentially from object to image. The compensation group consists of a first cemented doublet with negative optical power. The rear fixed group consists of two lenses: a second biconvex positive lens and a second negative meniscus lens, arranged sequentially from object to image. The focusing group consists of a third positive meniscus lens. The focusing group can move back and forth along the optical axis according to changes in ambient temperature to compensate for thermal differences in the optical system. The zoom group and the compensation group move back and forth along the optical axis to achieve continuous zoom imaging of the optical system.

[0007] Optionally, when the ambient temperature changes from 20℃ to t1, the focusing group moves towards the image side; when the ambient temperature changes from 20℃ to t2, the focusing group moves towards the object side; wherein -40℃≤t1<20℃, 20℃<t2≤75℃.

[0008] Optionally, when changing from a short focal length to a long focal length, both the zoom group and the compensation group move towards the image side; when changing from a long focal length to a short focal length, both the zoom group and the compensation group move towards the object side.

[0009] Optionally, the front and rear surface radii of curvature of the first negative meniscus negative lens are 208.432mm~254.7mm and 73.158mm~78.34mm, respectively; the front and rear surface radii of curvature of the first biconvex positive lens are 76.796mm~85.11mm and -1000mm~-512mm, respectively; the front and rear surface radii of curvature of the first positive meniscus positive lens are 70.486mm~72.456mm and 785.2mm~971.341mm, respectively; the front and rear surface radii of curvature of the first biconcave negative lens are -131.327mm~-120.156mm and 26.089mm~26.802mm, respectively; and the front and rear surface radii of curvature of the second positive meniscus positive lens are 27.73mm~28.722mm and 36.76mm, respectively. The first cemented doublet has front, cemented, and rear surface radii of curvature of -42.853mm to -41.538mm, -24.55mm to -23.947mm, and 101.16mm to 108.52mm, respectively; the second biconvex positive lens has front and rear surface radii of curvature of -20.041mm to -19.561mm and -39.99mm to -38.479mm, respectively; and the third positive meniscus has front and rear surface radii of curvature of -91.78mm to 142.275mm and 112.308mm to 153.653mm, respectively.

[0010] Optionally, the air gap between the first negative meniscus lens and the first biconvex positive lens is 2.63mm to 3mm, the air gap between the first biconvex positive lens and the first positive meniscus lens is 0.2mm to 0.5mm, the air gap between the first biconcave negative lens and the second positive meniscus lens is 1.29mm to 2.17mm, the air gap between the second biconvex positive lens and the second negative meniscus lens is 1.25mm to 1.37mm, and the air gap between the second negative meniscus lens and the third positive meniscus lens is 10mm to 10.27mm.

[0011] Optionally, the air gap between the front fixed group and the zoom group is 5 mm to 95.19 mm; the air gap between the zoom group and the compensation group is 6.52 mm to 67.09 mm; the air gap between the aperture stop and the rear fixed group is 1 mm; and the air gap between the compensation group and the rear fixed group is 2.5 mm to 46.25 mm.

[0012] Optionally, the first biconvex positive lens, the first positive meniscus positive lens, and the first biconcave negative lens are all made of calcium fluoride glass or barium fluoride glass.

[0013] Optionally, from the object side to the image side, after the focusing group, the short-wave infrared continuous zoom optical system also includes: a filter, a protective window, and an image plane arranged sequentially;

[0014] The filter is a flat glass with quartz glass as the substrate; the protective window is a flat glass with a thickness of 1mm and is made of sapphire.

[0015] Optionally, the air gap between the focusing group and the filter is 37.35 mm, the air gap between the filter and the protective window is 39.07 mm, and the air gap between the protective window and the image plane is 5.73 mm.

[0016] Optionally, the filter film has a transmission wavelength range of 900nm to 1700nm.

[0017] The short-wave infrared continuous zoom optical system provided in this application adopts a two-element (zoom group and compensation group) mechanical compensation method. The zoom group and compensation group move back and forth simultaneously along the optical axis. Both groups are responsible for the zoom ratio of the optical system, which enables the optical system to zoom quickly. It can achieve clear and stable image switching from short focal length to long focal length in 6 seconds. Moreover, the aberrations of the optical system are easily balanced, the image plane position is stable, and the zooming method is simple. Furthermore, by adjusting the focus group to move back and forth along the optical axis, it can maintain a wide temperature range (-60℃ to 75℃). With consistent image plane, it achieves high-contrast imaging over a wide temperature range (-60℃ to 75℃) while maintaining a large focal length. This ensures that the transfer function at a spatial frequency of 34 lp / mm is greater than 0.4 across the entire field of view, enabling high-contrast imaging over this wide temperature range. Furthermore, by using lens materials with low refractive index and low dispersion, it can effectively correct secondary spectral distortion, suppress chromatic aberration in the optical system, and effectively reduce optical system distortion. This results in distortion of <|5%|% across the short to long focal length range, achieving high-contrast and low-distortion imaging.

[0018] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the short-wave infrared continuous zoom optical system in the short focal length position in the embodiments of this application;

[0020] Figure 2This is a schematic diagram of the short-wave infrared continuous zoom optical system at the telephoto position in an embodiment of this application;

[0021] Figure 3 The optical transfer function of the short-wave infrared continuous zoom optical system in this embodiment at the short focal length position at -60℃;

[0022] Figure 4 The optical transfer function of the short-wave infrared continuous zoom optical system in this embodiment at the short focal length position at 20°C;

[0023] Figure 5 The optical transfer function of the short-wave infrared continuous zoom optical system in this embodiment at the short focal length position at 75°C;

[0024] Figure 6 The optical transfer function of the short-wave infrared continuous zoom optical system in this embodiment at the telephoto position at -60℃;

[0025] Figure 7 The optical transfer function of the short-wave infrared continuous zoom optical system at the telephoto position in this embodiment of the application at 20°C;

[0026] Figure 8 The optical transfer function of the short-wave infrared continuous zoom optical system at the telephoto position in this embodiment of the application at 75°C;

[0027] Figure 9 The distortion curve of the short-wave infrared continuous zoom optical system in the embodiments of this application at the short focal length position;

[0028] Figure 10 This is the distortion curve of the short-wave infrared continuous zoom optical system at the telephoto position in the embodiments of this application. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] This application provides a short-wave infrared continuous zoom optical system, such as... Figure 1-2 As shown, it includes:

[0031] The following groups are arranged sequentially from the object side to the image side: front fixed group 1 with positive optical power, zoom group 2 with negative optical power, compensation group 3 with negative optical power, aperture stop 4, rear fixed group 5 with positive optical power, and focusing group 6 with positive optical power.

[0032] The front fixed group 1 consists of three lenses, namely, a first negative meniscus negative lens 11, a first biconvex positive lens 12, and a first positive meniscus positive lens 13, arranged from object to image. The zoom group 2 consists of two lenses, namely, a first biconcave negative lens 21 and a second positive meniscus positive lens 22, arranged from object to image. The compensation group 3 is a first cemented doublet 31 with negative optical power. The rear fixed group 5 consists of two lenses, namely, a second biconvex positive lens 51 and a second negative meniscus negative lens 52, arranged from object to image. The focusing group 6 is a third positive meniscus positive lens 61. The focusing group 6 can move back and forth along the optical axis according to changes in ambient temperature to compensate for thermal differences in the optical system. The zoom group 2 and the compensation group 3 move back and forth along the optical axis to achieve continuous zoom imaging of the optical system.

[0033] In this embodiment, the first negative meniscus lens 11, the first biconvex positive lens 12, the first positive meniscus lens 13, the first biconcave negative lens 21, the second positive meniscus lens 22, the first cemented doublet lens 31, the second biconvex positive lens 51, the second negative meniscus lens 52, and the third positive meniscus lens 61 can all be spherical lenses, and the material can all be glass.

[0034] In this embodiment, by adjusting the axial movement of the focusing group, image plane consistency can be maintained within a wide temperature range (-60℃ to 75℃). While achieving a large focal length, the transfer function of the entire field of view at a spatial frequency of 34lp / mm is greater than 0.4 within the wide temperature range (-60℃ to 75℃), thus achieving high-contrast imaging within the wide temperature range (-60℃ to 75℃).

[0035] In specific implementation, when the ambient temperature changes from 20℃ to t1, the focusing group 6 moves towards the image side; when the ambient temperature changes from 20℃ to t2, the focusing group 6 moves towards the object side; wherein, -40℃≤t1<20℃, 20℃<t2≤75℃.

[0036] In this embodiment, a two-element mechanical compensation method (magnification group 2 and compensation group 3) is adopted, and the magnification group 2 and compensation group 3 move forward or backward along the optical axis at the same time. Both the magnification group 2 and compensation group 3 are responsible for the magnification ratio of the optical system, which makes the optical system zoom fast. It can achieve a stable switch from short focal length to long focal length or from long focal length to short focal length in 6 seconds. Moreover, the aberration of the optical system is easy to balance, the image plane position is stable, and the zoom method is simple.

[0037] In practice, when changing from a short focal length to a long focal length, both zoom group 2 and compensation group 3 move towards the image side; when changing from a long focal length to a short focal length, both zoom group 2 and compensation group 3 move towards the object side.

[0038] In this embodiment, at least two lenses in the front fixed group 1 are made of ultra-low dispersion glass. At least one lens in the zoom group 2 is also made of ultra-low dispersion glass. The ultra-low dispersion glass can be calcium fluoride glass or barium fluoride glass. Thus, due to the low dispersion property of the ultra-low dispersion glass, it can effectively correct chromatic aberration in the secondary spectral suppression system, effectively reducing the distortion of the optical system. This results in the optical system having a transfer function greater than 0.4 at a spatial frequency of 34 lp / mm across the entire field of view, with distortion < |5%|, achieving high-contrast, low-distortion imaging.

[0039] In specific implementation, the first biconvex positive lens 12, the first positive meniscus positive lens 13, and the first biconcave negative lens 21 can all be made of calcium fluoride glass or barium fluoride glass.

[0040] In some embodiments, the front and rear surface radii of curvature of the first negative meniscus negative lens 11 are 208.432mm to 254.7mm and 73.158mm to 78.34mm, respectively; the front and rear surface radii of curvature of the first biconvex positive lens 12 are 76.796mm to 85.11mm and -1000mm to -512mm, respectively; the front and rear surface radii of curvature of the first positive meniscus positive lens 13 are 70.486mm to 72.456mm and 785.2mm to 971.341mm, respectively; the front and rear surface radii of curvature of the first biconcave negative lens 21 are -131.327mm to -120.156mm and 26.089mm to 26.802mm, respectively; and the front and rear surface radii of curvature of the second positive meniscus positive lens 22 are 27.73mm to 28.722mm and 36. The front, cemented, and rear surfaces of the first cemented doublet lens 31 have radii of curvature of -42.853mm to -41.538mm, -24.55mm to -23.947mm, and 101.16mm to 108.52mm, respectively; the front and rear surfaces of the second biconvex positive lens 51 have radii of curvature of -21.884mm to -21.224mm, respectively; the front and rear surfaces of the second negative meniscus negative lens 52 have radii of curvature of -20.041mm to -19.561mm and -39.99mm to -38.479mm, respectively; and the front and rear surfaces of the third positive meniscus positive lens 61 have radii of curvature of 91.78mm to 142.275mm and 112.308mm to 153.653mm, respectively.

[0041] In some embodiments, the air gap between the first negative meniscus negative lens 11 and the first biconvex positive lens 12 is 2.63 mm to 3 mm, the air gap between the first biconvex positive lens 12 and the first positive meniscus positive lens 13 is 0.2 mm to 0.5 mm, the air gap between the first biconcave negative lens 21 and the second positive meniscus positive lens 22 is 1.29 mm to 2.17 mm, the air gap between the second biconvex positive lens 51 and the second negative meniscus negative lens 52 is 1.25 mm to 1.37 mm, and the air gap between the second negative meniscus negative lens 52 and the third positive meniscus positive lens 61 is 10 mm to 10.27 mm.

[0042] In some embodiments, the air gap between the front fixed group 1 and the zoom group 2 is 5 mm to 95.19 mm; the air gap between the zoom group 2 and the compensation group 3 is 6.52 mm to 67.09 mm; the air gap between the aperture stop 4 and the rear fixed group 5 is 1 mm; and the air gap between the compensation group 3 and the rear fixed group 5 is 2.5 mm to 46.25 mm.

[0043] In some embodiments, the first negative meniscus lens 11 has a refractive index of 1.60 and an Abbe number of 38.0. The first biconvex positive lens 12 has a refractive index of 1.43 and an Abbe number of 95.0. The first positive meniscus lens 13 has a refractive index of 1.43 and an Abbe number of 95.0. The first biconcave negative lens 21 has a refractive index of 1.47 and an Abbe number of 81.6. The second positive meniscus lens 22 has a refractive index of 1.76 and an Abbe number of 27.5. In the first cemented doublet lens 31, one of the two cemented lenses has a refractive index of 1.96 and an Abbe number of 17.5; the other lens has a refractive index of 1.68 and an Abbe number of 55.5. The second biconvex positive lens 51 has a refractive index of 1.57 and an Abbe number of 71.3. The second negative meniscus lens 52 has a refractive index of 1.81 and an Abbe number of 22.7. The third positive meniscus lens 61 has a refractive index of 1.83 and an Abbe number of 42.7.

[0044] In some embodiments, such as Figure 1-2 As shown, from the object side to the image side, after the focusing group, the short-wave infrared continuous zoom optical system also includes: a filter 7, a protective window 8, and an image plane 9 arranged in sequence.

[0045] In this embodiment, the filter 7 is a flat glass with quartz glass as the substrate; the protective window 8 is a charge-coupled device (CCD), which is a flat glass with a thickness of 1 mm and is made of sapphire.

[0046] In this embodiment, the air gap between the focusing group 6 and the filter 7 can be 37.35 mm, the air gap between the filter 7 and the protective window 8 can be 39.07 mm, and the air gap between the protective window 8 and the image plane 9 can be 5.73 mm.

[0047] In this embodiment, the transmission band of the filter 7 can be 900nm to 1700nm. It can be replaced with any band within this range according to different usage requirements. In this way, different spectral bands can be switched to meet the purpose of multiple application scenarios.

[0048] The short-wave infrared continuous zoom optical system provided in this application embodiment, when the optical system is in the short focal length position, such as Figure 3-5 As shown, the transfer function values ​​for the entire field of view are greater than 0.4 at -60℃, 20℃, and +75℃, ensuring clear imaging across the entire field of view and spectral range. When the optical system is at the telephoto position, as... Figure 6-8 As shown, the transfer function values ​​for the entire field of view are all greater than 0.4 at -60℃, 20℃, and +75℃, resulting in clear imaging across the entire field of view and spectral range. Figure 9 and Figure 10 As shown, the short-wave infrared continuous zoom optical system provided in this application embodiment has a distortion of less than |5%| for all fields of view at all focal lengths, which can effectively reduce the image distortion ratio.

[0049] The short-wave infrared continuous zoom optical system provided in this application adopts a two-element (zoom group and compensation group) mechanical compensation method. The zoom group and compensation group move back and forth simultaneously along the optical axis. Both groups are responsible for the zoom ratio of the optical system, which enables the optical system to zoom quickly. It can achieve clear and stable image switching from short focal length to long focal length in 6 seconds. Moreover, the aberrations of the optical system are easily balanced, the image plane position is stable, and the zooming method is simple. Furthermore, by adjusting the focus group to move back and forth along the optical axis, it can achieve a wide temperature range (-60℃ to 75℃). Maintaining image plane consistency, while achieving a large focal length, it ensures high-contrast imaging over a wide temperature range (-60℃ to 75℃), resulting in a transfer function greater than 0.4 at a spatial frequency of 34 lp / mm across the entire field of view. Furthermore, by using low-dispersion lens materials, it can effectively correct secondary spectral distortion, suppress chromatic aberration in the optical system, and reduce optical system distortion, resulting in distortion <|5%|% across the short to long focal length range, achieving high-contrast, low-distortion imaging.

[0050] In an optional embodiment, the parameters of each optical element in the shortwave infrared continuous zoom optical system are shown in Table 1.

[0051] Table 1

[0052]

[0053]

[0054] The front and rear surfaces of the first negative meniscus lens 11 are numbered 1 and 2, respectively. The front and rear surfaces of the first biconvex positive lens 12 are numbered 3 and 4, respectively. The front and rear surfaces of the first positive meniscus lens 13 are numbered 5 and 6, respectively. The front and rear surfaces of the first biconcave negative lens 21 are numbered 7 and 8, respectively. The front and rear surfaces of the second positive meniscus lens 22 are numbered 9 and 10, respectively. The front, cemented, and rear surfaces of the first cemented doublet lens 31 are numbered 11, 12, and 13, respectively. The surface of the aperture stop 4 is numbered 14. The front and rear surfaces of the second biconvex positive lens 51 are numbered 15 and 16, respectively. The front and rear surfaces of the second negative meniscus lens 52 are numbered 17 and 18, respectively. The front and rear surfaces of the third positive meniscus lens 61 are numbered 19 and 20, respectively. The front and rear surfaces of the filter 7 are numbered 21 and 22. The front and rear surfaces of the protective window 8 are numbered 23 and 24. The surface number of image plane 9 is 25. The air gap between elements is the air gap between the current element and the next element. For example, the air gap of the first negative meniscus negative lens 11 is the air gap between the first negative meniscus negative lens 11 and the first biconvex positive lens 12.

[0055] In this embodiment, the following indicators can be achieved:

[0056] a) Focal length: 33mm~330mm;

[0057] b) F / #: 6.6~50;

[0058] c) Band: 900nm~1700nm;

[0059] d) MTF (-60℃~75℃): Full field of view >0.4@34mm / lp;

[0060] e) Suitable ambient temperature: -60℃~75℃

[0061] f) Distortion: <|5%|%.

[0062] In an optional embodiment, the parameters of each optical element in the shortwave infrared continuous zoom optical system are shown in Table 2.

[0063] Table 2

[0064]

[0065] The front and rear surfaces of the first negative meniscus lens 11 are numbered 1 and 2, respectively. The front and rear surfaces of the first biconvex positive lens 12 are numbered 3 and 4, respectively. The front and rear surfaces of the first positive meniscus lens 13 are numbered 5 and 6, respectively. The front and rear surfaces of the first biconcave negative lens 21 are numbered 7 and 8, respectively. The front and rear surfaces of the second positive meniscus lens 22 are numbered 9 and 10, respectively. The front, cemented, and rear surfaces of the first cemented doublet lens 31 are numbered 11, 12, and 13, respectively. The surface of the aperture stop 4 is numbered 14. The front and rear surfaces of the second biconvex positive lens 51 are numbered 15 and 16, respectively. The front and rear surfaces of the second negative meniscus lens 52 are numbered 17 and 18, respectively. The front and rear surfaces of the third positive meniscus lens 61 are numbered 19 and 20, respectively. The front and rear surfaces of the filter 7 are numbered 21 and 22. The front and rear surfaces of the protective window 8 are numbered 23 and 24. The surface number of image plane 9 is 25. The air gap between elements is the air gap between the current element and the next element. For example, the air gap of the first negative meniscus negative lens 11 is the air gap between the first negative meniscus negative lens 11 and the first biconvex positive lens 12.

[0066] In this embodiment, the following indicators can be achieved:

[0067] a) Focal length: 33mm~330mm;

[0068] b) F / #: 6.6~50;

[0069] c) Band: 900nm~1700nm;

[0070] d) MTF (-60℃~75℃): Full field of view >0.4@34mm / lp;

[0071] e) Suitable ambient temperature: -60℃~75℃

[0072] f) Distortion: <|5%|%.

[0073] In an optional embodiment, the parameters of each optical element in the shortwave infrared continuous zoom optical system are shown in Table 3.

[0074] Table 3

[0075]

[0076]

[0077] The front and rear surfaces of the first negative meniscus lens 11 are numbered 1 and 2, respectively. The front and rear surfaces of the first biconvex positive lens 12 are numbered 3 and 4, respectively. The front and rear surfaces of the first positive meniscus lens 13 are numbered 5 and 6, respectively. The front and rear surfaces of the first biconcave negative lens 21 are numbered 7 and 8, respectively. The front and rear surfaces of the second positive meniscus lens 22 are numbered 9 and 10, respectively. The front, cemented, and rear surfaces of the first cemented doublet lens 31 are numbered 11, 12, and 13, respectively. The surface of the aperture stop 4 is numbered 14. The front and rear surfaces of the second biconvex positive lens 51 are numbered 15 and 16, respectively. The front and rear surfaces of the second negative meniscus lens 52 are numbered 17 and 18, respectively. The front and rear surfaces of the third positive meniscus lens 61 are numbered 19 and 20, respectively. The front and rear surfaces of the filter 7 are numbered 21 and 22. The front and rear surfaces of the protective window 8 are numbered 23 and 24. The surface number of image plane 9 is 25. The air gap between elements is the air gap between the current element and the next element. For example, the air gap of the first negative meniscus negative lens 11 is the air gap between the first negative meniscus negative lens 11 and the first biconvex positive lens 12.

[0078] In this embodiment, the following indicators can be achieved:

[0079] a) Focal length: 33mm~330mm;

[0080] b) F / #: 6.6~50;

[0081] c) Band: 900nm~1700nm;

[0082] d) MTF (-60℃~75℃): Full field of view >0.4@34mm / lp;

[0083] e) Suitable ambient temperature: -60℃~75℃

[0084] f) Distortion: <|5%|%.

[0085] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0086] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0087] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0088] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A short-wave infrared continuous zoom optical system, characterized in that, From the object side to the image side, it consists of a front fixed group with positive optical power, a zoom group with negative optical power, a compensation group with negative optical power, an aperture stop, a rear fixed group with positive optical power, and a focusing group with positive optical power. The front fixed group consists of three lenses, from object to image: a first negative meniscus lens, a first biconvex positive lens, and a first positive meniscus lens. The zoom group consists of two lenses, from object to image: a first biconcave negative lens and a second positive meniscus lens. The compensation group is a first cemented doublet with negative optical power. The rear fixed group consists of two lenses, from object to image: a second biconvex positive lens and a second negative meniscus lens. The focusing group is a third positive meniscus lens. The focusing group can move back and forth along the optical axis according to changes in ambient temperature to compensate for thermal differences in the optical system. The zoom group and the compensation group move back and forth along the optical axis to achieve continuous zoom imaging of the optical system. When the ambient temperature changes from 20℃ to t1, the focusing group moves towards the image side; when the ambient temperature changes from 20℃ to t2, the focusing group moves towards the object side; wherein, -40℃≤t1<20℃, 20℃<t2≤75℃; The first negative meniscus negative lens has front and rear surface radii of curvature of 208.432mm~254.7mm and 73.158mm~78.34mm, respectively; the first biconvex positive lens has front and rear surface radii of curvature of 76.796mm~85.11mm and -1000mm~-512mm, respectively; the first positive meniscus positive lens has front and rear surface radii of curvature of 70.486mm~72.456mm and 785.2mm~971.341mm, respectively; the first biconcave negative lens has front and rear surface radii of curvature of -131.327mm~-120.156mm and 26.089mm~26.802mm, respectively; and the second positive meniscus positive lens has front and rear surface radii of curvature of 27.73mm~28.722mm and 36.762mm, respectively. The front, cemented, and rear surfaces of the first cemented doublet lens have radii of curvature of -42.853mm to -41.538mm, -24.55mm to -23.947mm, and 101.16mm to 108.52mm, respectively; the front and rear surfaces of the second biconvex positive lens have radii of curvature of 44.344mm to 49.66mm and -21.884mm to -21.224mm, respectively; the front and rear surfaces of the second negative meniscus negative lens have radii of curvature of -20.041mm to -19.561mm and -39.99mm to -38.479mm, respectively; and the front and rear surfaces of the third positive meniscus positive lens have radii of curvature of 91.78mm to 142.275mm and 112.308mm to 153.653mm, respectively.

2. The short-wave infrared continuous zoom optical system according to claim 1, characterized in that, When changing from a short focal length to a long focal length, both the zoom group and the compensation group move towards the image side; when changing from a long focal length to a short focal length, both the zoom group and the compensation group move towards the object side.

3. The short-wave infrared continuous zoom optical system according to claim 1, characterized in that, The air gap between the first negative meniscus lens and the first biconvex positive lens is 2.63 mm to 3 mm, the air gap between the first biconvex positive lens and the first positive meniscus lens is 0.2 mm to 0.5 mm, the air gap between the first biconcave negative lens and the second positive meniscus lens is 1.29 mm to 2.17 mm, the air gap between the second biconvex positive lens and the second negative meniscus lens is 1.25 mm to 1.37 mm, and the air gap between the second negative meniscus lens and the third positive meniscus lens is 10 mm to 10.27 mm.

4. The short-wave infrared continuous zoom optical system according to claim 1, characterized in that, The air gap between the front fixed group and the zoom group is 5 mm to 95.19 mm; the air gap between the zoom group and the compensation group is 6.52 mm to 67.09 mm; the air gap between the aperture stop and the rear fixed group is 1 mm; and the air gap between the compensation group and the rear fixed group is 2.5 mm to 46.25 mm.

5. The short-wave infrared continuous zoom optical system according to claim 1, characterized in that, The first biconvex positive lens, the first positive meniscus positive lens, and the first biconcave negative lens are all made of calcium fluoride glass or barium fluoride glass.

6. The short-wave infrared continuous zoom optical system according to claim 1, characterized in that, From the object side to the image side, following the focusing group, it also includes: The filter, guard window, and image plane are set sequentially. The filter is a flat glass with quartz glass as the substrate; the protective window is a flat glass with a thickness of 1 mm and is made of sapphire.

7. The short-wave infrared continuous zoom optical system according to claim 6, characterized in that, The air gap between the focusing group and the filter is 37.35 mm, the air gap between the filter and the protective window is 39.07 mm, and the air gap between the protective window and the image plane is 5.73 mm.

8. The short-wave infrared continuous zoom optical system according to claim 6, characterized in that, The filter film has a transmission wavelength range of 900nm to 1700nm.

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