30x shortwave infrared zoom lens

Abstract

The invention belongs to the field of optical imaging technology, and relates to a 30x short-wave infrared zoom lens, including a front fixed group, a zoom group, a compensation group and a rear fixed group arranged on the same optical axis from front to back along the incident direction of the optical path, the front fixed group includes a front fixed group three-cemented lens and a front fixed group plano-convex lens arranged from left to right; the zoom group includes a zoom group positive meniscus lens, a zoom group negative meniscus lens and a zoom group double-cemented lens arranged from left to right; the compensation group includes a compensation group double-convex lens and a compensation group double-cemented lens arranged from left to right; the rear fixed group includes a rear fixed group positive meniscus lens, a rear fixed group first negative meniscus lens, a rear fixed group double-convex lens and a rear fixed group second negative meniscus lens arranged from left to right. The lens provided by the invention has a zoom ratio of up to 30 times, can clearly image in the full focal length, has object vignetting and four-corner dark area phenomenon during zooming, has no stuck, and can reduce price cost.

Description

Technical Field

[0001] The invention belongs to the technical field of optical imaging and relates to a 30-fold short-wave infrared zoom lens. Background Art

[0002] Short-wave infrared technology is a new field in current visual machines. Its imaging spectrum range is 0.9-1.7μm. It is one of the three atmospheric windows of infrared and lies between visible light and medium waves. Therefore, it has the characteristics of visible light detail imaging and some thermal imaging characteristics.

[0003] Shortwave light in the environment accounts for about 40%-50% of the sunlight spectrum, so its spectral imaging capability is comparable to visible light. At night, the wavelengths of atmospheric glow and night sky light are mainly in shortwave, so the low-light effect of shortwave is very good. Due to its relatively small wavelength and small impact from environmental factors, it is widely used in spectral imaging, maritime reconnaissance through smoke, night vision enhancement, missile satellite defense, etc., and its advantages are unmatched by any other camera.

[0004] Short-wave infrared cameras have been widely used abroad, but the development of short-wave infrared technology in my country is very slow. The development of short-wave infrared lenses is still in its initial stage. The existing short-wave infrared lenses have the following problems: (1) The zoom ratio is generally around 10 times, which is relatively low and cannot meet the purpose of large-field-of-view search and long-distance detection; (2) The zoom process is prone to dark areas in the four corners, affecting the image clarity; (3) The price is expensive. Summary of the invention

[0005] In view of the technical problems existing in the existing short-wave infrared lenses, the present invention provides a 30x short-wave infrared zoom lens with a zoom ratio of up to 30x, clear imaging within the full focal length, no vignetting and dark areas in the four corners during the zooming process, no jamming, and reduced price cost.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A 30x short-wave infrared zoom lens comprises a front fixed group, a zoom group, a compensation group and a rear fixed group which are arranged on the same optical axis from front to back along the incident direction of the optical path;

[0008] The front fixed group includes a front fixed group of three cemented lenses 1 and a front fixed group of plano-convex lenses 2 arranged sequentially from front to back; the front fixed group of three cemented lenses 1 includes a front fixed group of negative meniscus lens 1-1, a front fixed group of biconvex lens 1-2 and a front fixed group of biconcave lens 1-3 which are tightly connected sequentially from left to right;

[0009] The zoom group includes a zoom group positive meniscus lens 3, a zoom group negative meniscus lens 4 and a zoom group double cemented lens 5 arranged in sequence from front to back; the zoom group double cemented lens 5 includes a zoom group biconcave lens 5-1 and a zoom group first positive meniscus lens 5-2 which are tightly connected in sequence from left to right;

[0010] The compensation group includes a compensation group biconvex lens 6 and a compensation group double cemented lens 7 arranged sequentially from front to back; the compensation group double cemented lens 7 includes a compensation group biconvex lens 7-1 and a compensation group biconcave lens 7-2 which are closely connected sequentially from left to right;

[0011] The rear fixed group includes a rear fixed group positive meniscus lens 8, a rear fixed group first negative meniscus lens 9, a rear fixed group biconvex lens 10 and a rear fixed group second negative meniscus lens 11 which are arranged in sequence from front to back.

[0012] Furthermore, the distance between the front fixed group biconcave lens 1-3 and the front fixed group plano-convex lens 2 is 3.75mm; the distance between the zoom group positive meniscus lens 3 and the zoom group negative meniscus lens 4 is 0.65mm; the distance between the zoom group negative meniscus lens 4 and the zoom group biconcave lens 5-1 is 15.78mm; the distance between the compensation group biconvex lens 6 and the compensation group biconvex lens 7-1 is 0.5mm; the distance between the rear fixed group positive meniscus lens 8 and the rear fixed group first negative meniscus lens 9 is 1.39mm; the distance between the rear fixed group first negative meniscus lens 9 and the rear fixed group biconvex lens 10 is 23.44mm; the distance between the rear fixed group biconvex lens 10 and the rear fixed group second negative meniscus lens 11 is 1.36mm.

[0013] Furthermore, the distance L1 between the front fixed group plano-convex lens 2 and the positive meniscus lens 3 of the zoom group is 5 to 191.79 mm; the distance L2 between the first positive meniscus lens 5-2 of the zoom group and the double convex lens 6 of the compensation group is 6.8 to 216.48 mm; the distance L3 between the double concave lens 7-2 of the compensation group and the positive meniscus lens 8 of the rear fixed group is 5 to 27.89 mm; the distance between the second negative meniscus lens 11 of the rear fixed group and the image plane is 12.29 mm.

[0014] Furthermore, the front fixed group three-cemented lens 1, the front fixed group plano-convex lens 2, the zoom group positive meniscus lens 3, the zoom group negative meniscus lens 4, the zoom group double-cemented lens 5, the compensation group double-convex lens 6, the compensation group double-cemented lens 7, the rear fixed group positive meniscus lens 8, the rear fixed group first negative meniscus lens 9, the rear fixed group double-convex lens 10 and the rear fixed group second negative meniscus lens 11 are all made of spherical glass.

[0015] Furthermore, the spherical radius of the three-cemented lens 1 in the front fixed group is 194.34mm, 98.63mm, -196.82mm, and 89.3mm from left to right respectively; the left spherical radius of the plano-convex lens 2 in the front fixed group is 92.78mm, and the right spherical radius of the plano-convex lens 2 in the front fixed group is infinite; the left spherical radius of the positive meniscus lens 3 in the variable magnification group is 61.68mm, and the right spherical radius of the positive meniscus lens 3 in the variable magnification group is 235.96mm; the left spherical radius of the negative meniscus lens 4 in the variable magnification group is 90mm, and the right spherical radius of the negative meniscus lens 4 in the variable magnification group is 31.53mm; the spherical radius of the double-cemented lens 5 in the variable magnification group is -50.26mm, 22.82mm, and 68.62mm from left to right respectively; the left spherical radius of the double convex lens 6 in the compensation group is 410.47mm, and the double convex lens in the compensation group is 410.47mm. The right spherical radius of the mirror 6 is -45.25mm; the spherical radius of the double cemented lens 7 of the compensation group is 19.92mm, -18.03mm and 18.87mm from left to right respectively; the left spherical radius of the positive meniscus lens 8 of the rear fixed group is 17.46mm, and the right spherical radius of the positive meniscus lens 8 of the rear fixed group is 49.53mm; the left spherical radius of the first negative meniscus lens 9 of the rear fixed group is 620.37mm, and the right spherical radius of the first negative meniscus lens 9 of the rear fixed group is 21.38mm; the left spherical radius of the biconvex lens 10 of the rear fixed group is 49.68mm, and the right spherical radius of the biconvex lens 10 of the rear fixed group is -30.86mm; the left spherical radius of the second negative meniscus lens 11 of the rear fixed group is -19.75mm, and the right spherical radius of the second negative meniscus lens 11 of the rear fixed group is -35.01mm.

[0016] Furthermore, the thicknesses of the front fixed group negative meniscus lens 1-1, the front fixed group biconvex lens 1-2 and the front fixed group biconcave lens 1-3 are 8mm, 32mm and 5mm respectively; the thickness of the front fixed group plano-convex lens 2 is 16.54mm; the thickness of the zoom group positive meniscus lens 3 is 11.13mm; the thickness of the zoom group negative meniscus lens 4 is 2mm; the thickness of the zoom group biconcave lens 5-1 and the first zoom group positive meniscus lens 5-2 are 5mm and 11. 07mm; the thickness of the compensation group biconvex lens 6 is 3.74mm; the thickness of the compensation group biconvex lens 7-1 and the compensation group biconcave lens 7-2 are 5.37mm and 3.84mm respectively; the thickness of the rear fixed group positive meniscus lens 8 is 2.93mm; the thickness of the rear fixed group first negative meniscus lens 9 is 2.53mm; the thickness of the rear fixed group biconvex lens 10 is 3.65mm; the thickness of the rear fixed group second negative meniscus lens 11 is 1.58mm.

[0017] Furthermore, the materials of the front fixed group negative meniscus lens 1-1, the front fixed group biconvex lens 1-2 and the front fixed group biconcave lens 1-3 are N-SF56, H-FK69 and LF5HT respectively; the material of the front fixed group plano-convex lens 2 is D-ZF10; the material of the zoom group positive meniscus lens 3 is H-ZF52HT; the material of the zoom group negative meniscus lens 4 is N-LAK21; the material of the zoom group biconcave lens 5-1 and lens 502 is H- LAF3 and H-ZLAF50B; the material of the compensation group biconvex lens 6 is F14; the materials of the compensation group biconvex lens 7-1 and the compensation group biconcave lens 7-2 are H-PK63 and H-TF7; the material of the rear fixed group positive meniscus lens 8 is F5; the material of the rear fixed group first negative meniscus lens 9 is ZF4; the material of the rear fixed group biconvex lens 10 is H-QK3L; the material of the rear fixed group second negative meniscus lens 11 is D-LAF731.

[0018] Furthermore, in the process from the short focus state to the long focus state, L1 gradually increases, L2 gradually decreases, and L3 gradually increases; in the process from the long focus state to the short focus state, L1 gradually decreases, L2 gradually increases, and L3 gradually decreases.

[0019] Furthermore, the focal length of the front fixed group is 315.66 mm; the focal length of the zoom group is -41.7 mm; the focal length of the compensation group is 55.56 mm; the focal length of the rear fixed group is 203.14 mm; and the focal length of the lens is 15 mm to 450 mm.

[0020] The beneficial effects of the present invention are:

[0021] 1. A 30x short-wave infrared zoom lens provided by the present invention comprises a front fixed group, a zoom group, a compensation group and a rear fixed group arranged on the same optical axis from front to back along the incident direction of the optical path; the front fixed group comprises a front fixed group triple cemented lens 1 and a front fixed group plano-convex lens 2 arranged from front to back; the front fixed group triple cemented lens 1 comprises a front fixed group negative meniscus lens 1-1, a front fixed group double convex lens 1-2 and a front fixed group double concave lens 1-3 which are tightly connected from left to right; the zoom group comprises a zoom group positive meniscus lens 3, a zoom group negative meniscus lens 4 and a zoom group arranged from front to back Double glued lens 5; the zoom group double glued lens 5 includes a zoom group double concave lens 5-1 and a zoom group first positive meniscus lens 5-2 which are tightly connected from left to right; the compensation group includes a compensation group double convex lens 6 and a compensation group double glued lens 7 which are arranged in sequence from front to back; the compensation group double glued lens 7 includes a compensation group double convex lens 7-1 and a compensation group double concave lens 7-2 which are tightly connected from left to right; the rear fixed group includes a rear fixed group positive meniscus lens 8, a rear fixed group first negative meniscus lens 9, a rear fixed group double convex lens 10 and a rear fixed group second negative meniscus lens 11 which are arranged in sequence from front to back. The zoom lens provided by the present invention has a focal length range of 15mm to 450mm, a zoom ratio of up to 30 times, and a good imaging effect; it can well meet the purpose of large field of view search and long-distance detection; the present invention adopts a positive group compensation zooming method, and the cam curve is smooth without a stuck phenomenon.

[0022] 2. The front fixed group three-cemented lens 1, the front fixed group plano-convex lens 2, the zoom group positive meniscus lens 3, the zoom group negative meniscus lens 4, the zoom group double-cemented lens 5, the compensation group double-convex lens 6, the compensation group double-cemented lens 7, the rear fixed group positive meniscus lens 8, the rear fixed group first negative meniscus lens 9, the rear fixed group double-convex lens 10 and the rear fixed group second negative meniscus lens 11 provided by the present invention are all composed of spherical glass. The lens adopts spherical glass entirely, has low cost, and avoids the disadvantage of expensive aspherical glass.

[0023] 3. The 30x short-wave infrared zoom lens provided by the present invention has a photosensitive surface of 640×512@15μm and 320×256@30μm; a wavelength of 0.9-1.7μm; an aperture value of F4.5-F7; an overall optical length of 400mm; and a maximum distortion of 10% and a minimum of 0.2% in the full field of view of the system. The 30x short-wave infrared zoom lens provided by the present invention can achieve clear imaging within the full focal length, and there is no vignetting phenomenon during the entire zooming process, and no dark areas in the four corners will appear. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the optical path of a 30x short-wave infrared zoom lens provided by the present invention;

[0025] Figure 2-A This is the optical path diagram provided by this embodiment at a short focal length of 15 mm;

[0026] Figure 2-B Schematic diagram of the diffuse spot radius provided by this embodiment at a short focal length of 15 mm;

[0027] Figure 2-C The optical transfer function curve provided by this embodiment at a short focal length of 15 mm;

[0028] Figure 2-D The field curvature and distortion curves provided by this embodiment at a short focal length of 15 mm;

[0029] Figure 3-A This is the optical path diagram provided by this embodiment at a medium focal length of 70mm;

[0030] Figure 3-B This is a schematic diagram of the diffuse spot radius provided by this embodiment at a medium focal length of 70mm;

[0031] Figure 3-C The optical transfer function curve provided by this embodiment at a medium focal length of 70mm;

[0032] Figure 3-D The field curvature and distortion curves provided by this embodiment at a medium focal length of 70mm;

[0033] Figure 4-A This is the optical path diagram provided by this embodiment at a telephoto focal length of 450mm;

[0034] Figure 4-B This is a schematic diagram of the diffuse spot radius provided by this embodiment at a telephoto focal length of 450mm;

[0035] Figure 4-C This is the optical transfer function curve provided by this embodiment at a telephoto focal length of 450mm;

[0036] Figure 4-D The field curvature and distortion curves provided by this embodiment at a telephoto focal length of 450mm;

[0037] in:

[0038] Front fixed group: front fixed group triplet lens 1; front fixed group negative meniscus lens 1-1; front fixed group biconvex lens 1-2; front fixed group biconcave lens 1-3; front fixed group plano-convex lens 2;

[0039] Zoom group: zoom group positive meniscus lens 3; zoom group negative meniscus lens 4; zoom group double cemented lens 5; zoom group double concave lens 5-1; zoom group first positive meniscus lens 5-2;

[0040] Compensation group: compensation group biconvex lens 6; compensation group double cemented lens 7; compensation group biconvex lens 7-1; compensation group biconcave lens 7-2;

[0041] Rear fixed group: rear fixed group positive meniscus lens 8; rear fixed group first negative meniscus lens 9; rear fixed group double convex lens 10; rear fixed group second negative meniscus lens 11;

[0042] The short-wave infrared detector image plane is 12. DETAILED DESCRIPTION

[0043] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] Example

[0045] See also Figure 1 The 30x short-wave infrared zoom lens provided in this embodiment includes a front fixed group, a zoom group, a compensation group and a rear fixed group which are arranged on the same optical axis from front to back along the incident direction of the optical path. The left side of the front fixed group is the object side, and the right side of the rear fixed group is the image side. The distance L1 between the front fixed group and the zoom group provided in this embodiment is 5 to 191.79 mm; the distance L2 between the zoom group and the compensation group is 6.8 to 216.48 mm; the distance L3 between the compensation group and the rear fixed group is 5 to 27.89 mm; and the distance between the rear fixed group and the image plane is 12.29 mm.

[0046] The front fixed group provided in this embodiment includes a front fixed group of three cemented lenses 1 and a front fixed group of plano-convex lenses 2 arranged in sequence from left to right; the front fixed group of three cemented lenses 1 includes a front fixed group of negative meniscus lens 1-1, a front fixed group of biconvex lens 1-2 and a front fixed group of biconcave lens 1-3 tightly connected in sequence from left to right; the distance between the front fixed group of biconcave lens 1-3 and the front fixed group of plano-convex lens 2 is 3.75 mm.

[0047] The zoom group provided in this embodiment includes a zoom group positive meniscus lens 3, a zoom group negative meniscus lens 4 and a zoom group double cemented lens 5 which are arranged in sequence from left to right; the zoom group double cemented lens 5 includes a zoom group double concave lens 5-1 and a zoom group first positive meniscus lens 5-2 which are tightly connected in sequence from left to right; the distance between the zoom group positive meniscus lens 3 and the zoom group negative meniscus lens 4 is 0.65mm; the distance between the zoom group negative meniscus lens 4 and the zoom group double concave lens 5-1 is 15.78mm.

[0048] The compensation group provided in this embodiment includes a compensation group biconvex lens 6 and a compensation group double glued lens 7 arranged in sequence from left to right; the compensation group double glued lens 7 includes a compensation group biconvex lens 7-1 and a compensation group biconcave lens 7-2 tightly connected in sequence from left to right; the distance between the compensation group biconvex lens 6 and the compensation group biconvex lens 7-1 is 0.5mm.

[0049] The rear fixed group provided in this embodiment includes a rear fixed group positive meniscus lens 8, a rear fixed group first negative meniscus lens 9, a rear fixed group biconvex lens 10 and a rear fixed group second negative meniscus lens 11 which are arranged in sequence from left to right; the distance between the rear fixed group positive meniscus lens 8 and the rear fixed group first negative meniscus lens 9 is 1.39 mm; the distance between the rear fixed group first negative meniscus lens 9 and the rear fixed group biconvex lens 10 is 23.44 mm; the distance between the rear fixed group biconvex lens 10 and the rear fixed group second negative meniscus lens 11 is 1.36 mm.

[0050] The distance L1 between the front fixed group plano-convex lens 2 and the positive meniscus lens 3 of the zoom group provided in this embodiment is 5 to 191.79 mm; the distance L2 between the first positive meniscus lens 5-2 of the zoom group and the double convex lens 6 of the compensation group is 6.8 to 216.48 mm; the distance L3 between the double concave lens 7-2 of the compensation group and the positive meniscus lens 8 of the rear fixed group is 5 to 27.89 mm; the distance between the second negative meniscus lens 11 of the rear fixed group and the image plane is 12.29 mm.

[0051] The front fixed group three-cemented lens 1, the front fixed group plano-convex lens 2, the zoom group positive meniscus lens 3, the zoom group negative meniscus lens 4, the zoom group double-cemented lens 5, the compensation group double-convex lens 6, the compensation group double-cemented lens 7, the rear fixed group positive meniscus lens 8, the rear fixed group first negative meniscus lens 9, the rear fixed group double-convex lens 10 and the rear fixed group second negative meniscus lens 11 provided in this embodiment are all made of spherical glass.

[0052] The spherical radius of the three-cemented lens 1 in the front fixed group provided in this embodiment is 194.34mm, 98.63mm, -196.82mm and 89.3mm from left to right respectively; the left spherical radius of the plano-convex lens 2 in the front fixed group is 92.78mm, and the right spherical radius of the plano-convex lens 2 in the front fixed group is infinite; the left spherical radius of the positive meniscus lens 3 in the zoom group is 61.68mm, and the right spherical radius of the positive meniscus lens 3 in the zoom group is 235.96mm; the left spherical radius of the negative meniscus lens 4 in the zoom group is 90mm, and the right spherical radius of the negative meniscus lens 4 in the zoom group is 31.53mm; the spherical radius of the double-cemented lens 5 in the zoom group is -50.26mm, 22.82mm and 68.62mm from left to right respectively; the left spherical radius of the double convex lens 6 in the compensation group is 410.47mm, and the double convex lens 6 in the compensation group is 410.47mm. The right spherical radius of mirror 6 is -45.25mm; the spherical radius of the double cemented lens 7 in the compensation group is 19.92mm, -18.03mm and 18.87mm from left to right respectively; the left spherical radius of the positive meniscus lens 8 in the rear fixed group is 17.46mm, and the right spherical radius of the positive meniscus lens 8 in the rear fixed group is 49.53mm; the left spherical radius of the first negative meniscus lens 9 in the rear fixed group is 620.37mm, and the right spherical radius of the first negative meniscus lens 9 in the rear fixed group is 21.38mm; the left spherical radius of the biconvex lens 10 in the rear fixed group is 49.68mm, and the right spherical radius of the biconvex lens 10 in the rear fixed group is -30.86mm; the left spherical radius of the second negative meniscus lens 11 in the rear fixed group is -19.75mm, and the right spherical radius of the second negative meniscus lens 11 in the rear fixed group is -35.01mm.

[0053] The thicknesses of the front fixed group negative meniscus lens 1-1, the front fixed group biconvex lens 1-2 and the front fixed group biconcave lens 1-3 provided in this embodiment are 8mm, 32mm and 5mm respectively; the thickness of the front fixed group plano-convex lens 2 is 16.54mm; the thickness of the zoom group positive meniscus lens 3 is 11.13mm; the thickness of the zoom group negative meniscus lens 4 is 2mm; the thickness of the zoom group biconcave lens 5-1 and the first positive meniscus lens 5-2 of the zoom group are 5mm and 11.07mm respectively; the thickness of the compensation group biconvex lens 6 is 3.74mm; the thickness of the compensation group biconvex lens 7-1 and the compensation group biconcave lens 7-2 are 5.37mm and 3.84mm respectively; the thickness of the rear fixed group positive meniscus lens 8 is 2.93mm; the thickness of the rear fixed group first negative meniscus lens 9 is 2.53mm; the thickness of the rear fixed group biconvex lens 10 is 3.65mm; the thickness of the rear fixed group second negative meniscus lens 11 is 1.58mm.

[0054] The materials of the front fixed group negative meniscus lens 1-1, the front fixed group biconvex lens 1-2 and the front fixed group biconcave lens 1-3 provided in this embodiment are N-SF56, H-FK69 and LF5HT respectively; the material of the front fixed group plano-convex lens 2 is D-ZF10; the material of the zoom group positive meniscus lens 3 is H-ZF52HT; the material of the zoom group negative meniscus lens 4 is N-LAK21; the materials of the zoom group biconcave lens 5-1 and lens 502 are H-LAF3 and H-ZLAF50B; the material of the compensation group biconvex lens 6 is F14; the materials of the compensation group biconvex lens 7-1 and the compensation group biconcave lens 7-2 are H-PK63 and H-TF7; the material of the rear fixed group positive meniscus lens 8 is F5; the material of the rear fixed group first negative meniscus lens 9 is ZF4; the material of the rear fixed group biconvex lens 10 is H-QK3L; the material of the rear fixed group second negative meniscus lens 11 is D-LAF731.

[0055] The front fixed group of the system is a three-single-single structure, the zoom group is a single-single-double structure, the compensation group is a single-double structure, and the rear fixed group is composed of four single lenses. The system uses a total of 15 groups of lenses to achieve clear imaging within the full focal length;

[0056] The zoom lens provided in this embodiment is divided into a front fixed group, a variable magnification group, a compensation group and a rear fixed group, adopts a positive group compensation zoom mode, the cam curve is smooth, and there is no stuck phenomenon. And all spherical glass is used to avoid the expensive characteristics of aspherical glass.

[0057] The performance parameters of the lens system provided in this embodiment are:

[0058] The short-wave infrared zoom lens provided in this embodiment has a focal length range of 15mm to 450mm; the front fixed group focal length is 315.66mm, the zoom group focal length is -41.7mm, the compensation group focal length is 55.56mm, and the rear fixed group focal length is 203.14mm.

[0059] The lens provided in this embodiment is adapted to the photosensitive surface of 640×512@15μm and 320×256@30μm;

[0060] Wavelength: 0.9~1.7μm;

[0061] The aperture value of this system is F4.5 to F7;

[0062] The overall optical length is 400mm;

[0063] The lens provided in this embodiment has a maximum distortion of 10% and a minimum distortion of 0.2% within the entire field of view.

[0064] The 30x short-wave infrared zoom lens provided in this embodiment has L1 as the distance between the front fixed group and the zoom group, L2 as the distance between the zoom group and the compensation group, and L3 as the distance between the compensation group and the rear fixed group. In the process from short focus to long focus, L1 gradually increases, L2 gradually decreases, and L3 gradually increases. The zoom group moves linearly, and the compensation group moves nonlinearly. In the process from long focus to short focus, L1 gradually decreases, L2 gradually increases, and L3 gradually decreases.

[0065] Furthermore, taking imaging at different focal lengths as an example, the superior performance of the 30x short-wave infrared zoom lens provided by this embodiment is explained.

[0066] Experimental group: The focal lengths are 15mm for short focus, 70mm for medium focus, and 450mm for long focus. The light enters from the left side of the lens, passes through the front fixed group, zoom group, compensation group, and rear fixed group in sequence, and forms an image on the image plane 12 of the short-wave infrared detector. The number of pixels on the image plane is 640*512. The results are as follows: Figure 2-A , 2-B , 2-C, 2-D, 3-A, 3-B, 3-C, 3-D, 4-A, 4-B, 4-C and 4-D.

[0067] (1) From Figure 2-A , 2-B , 2-C and 2-D, we can know that when the short focus is 15mm, L1 is 5mm, L2 is 216.48mm, L3 is 5mm, and at short focus, the zoom group and the compensation group are separated; the maximum radius of the diffuse spot is 13.84μm; at a spatial frequency of 30lp / mm, the central field of view transfer function is greater than 0.6, and greater than 0.4 within the full field of view; the full field of view is 45 degrees, and its distortion is -10%.

[0068] (2) From Figure 3-A , 3-B From 3-C and 3-D, we can know that when the medium focus is 70mm, L1 is 106.99mm, L2 is 96.54mm, and L3 is 22.89mm; and at medium focus, the zoom group and the compensation group are close to each other and move to the middle position; the maximum radius of the diffuse spot is 9.871μm; at the spatial frequency of 30lp / mm, the central field of view transfer function is greater than 0.5, and the full field of view is greater than 0.3; the full field of view is 10°, and the distortion is less than 0.5%.

[0069] (3) From Figure 4-A , 4-BFrom 4-C and 4-D, we can see that when the telephoto focus is 450mm, L1 is 191.79mm, L2 is 6.8mm, and L3 is 27.89mm. At telephoto, the distance between the zoom group and the compensation group is the shortest; the maximum diffuse spot is 24.794μm; at a spatial frequency of 30lp / mm, the central field of view transfer function is greater than 0.5, and the full field of view is greater than 0.2; the full field of view is 1.5°, and the distortion is less than 2%.

[0070] The short-wave infrared zoom lens provided in this embodiment has a zoom ratio of up to 30 times and good imaging effect; there is no vignetting phenomenon in the entire zooming process, and no dark areas in the four corners; there is no jamming in the imaging, and it can well meet the purpose of large-field-of-view search and long-distance detection. The entire system uses spherical glass, avoiding the expensive characteristics of aspherical glass.

Claims

1. A 30x short-wave infrared zoom lens, characterized in that: The 30x short-wave infrared zoom lens comprises a front fixed group, a zoom group, a compensation group and a rear fixed group which are arranged on the same optical axis from front to back along the incident direction of the optical path; The front fixed group comprises a front fixed group of three cemented lenses (1) and a front fixed group of plano-convex lenses (2) arranged in sequence from front to back; the front fixed group of three cemented lenses (1) comprises a front fixed group of negative meniscus lenses (1-1), a front fixed group of biconvex lenses (1-2) and a front fixed group of biconcave lenses (1-3) which are tightly connected in sequence from left to right; The zoom group comprises a zoom group positive meniscus lens (3), a zoom group negative meniscus lens (4) and a zoom group double cemented lens (5) which are arranged in sequence from front to back; the zoom group double cemented lens (5) comprises a zoom group biconcave lens (5-1) and a zoom group first positive meniscus lens (5-2) which are tightly connected in sequence from left to right; The compensation group comprises a compensation group biconvex lens (6) and a compensation group double cemented lens (7) arranged in sequence from front to back; the compensation group double cemented lens (7) comprises a compensation group biconvex lens (7-1) and a compensation group biconcave lens (7-2) tightly connected in sequence from left to right; The rear fixed group comprises a rear fixed group positive meniscus lens (8), a rear fixed group first negative meniscus lens (9), a rear fixed group biconvex lens (10) and a rear fixed group second negative meniscus lens (11) which are arranged in sequence from front to back; The materials of the front fixed group negative meniscus lens (1-1), the front fixed group biconvex lens (1-2) and the front fixed group biconcave lens (1-3) are respectively N-SF56, H-FK69 and LF5HT; the material of the front fixed group plano-convex lens (2) is D-ZF10; the material of the zoom group positive meniscus lens (3) is H-ZF52HT; the material of the zoom group negative meniscus lens (4) is N-LAK21; the material of the zoom group biconcave lens (5-1) and the first zoom group positive meniscus lens (5-2) is H-ZF52HT; -LAF3 and H-ZLAF50B; the material of the compensation group biconvex lens (6) is F14; the material of the compensation group biconvex lens (7-1) and the compensation group biconcave lens (7-2) are H-PK63 and H-TF7; the material of the rear fixed group positive meniscus lens (8) is F5; the material of the rear fixed group first negative meniscus lens (9) is ZF4; the material of the rear fixed group biconvex lens (10) is H-QK3L; the material of the rear fixed group second negative meniscus lens (11) is D-LAF731.

2. The 30x short-wave infrared zoom lens according to claim 1, characterized in that: The distance between the front fixed group biconcave lens (1-3) and the front fixed group plano-convex lens (2) is 3.75 mm; the distance between the zoom group positive meniscus lens (3) and the zoom group negative meniscus lens (4) is 0.65 mm; the distance between the zoom group negative meniscus lens (4) and the zoom group biconcave lens (5-1) is 15.78 mm; the distance between the compensation group biconvex lens (6) and the compensation group biconvex lens (7-1) is 0.5 mm; the distance between the rear fixed group positive meniscus lens (8) and the rear fixed group first negative meniscus lens (9) is 1.39 mm; the distance between the rear fixed group first negative meniscus lens (9) and the rear fixed group biconvex lens (10) is 23.44 mm; the distance between the rear fixed group biconvex lens (10) and the rear fixed group second negative meniscus lens (11) is 1.36 mm.

3. The 30x short-wave infrared zoom lens according to claim 2, characterized in that: The distance L1 between the front fixed group plano-convex lens (2) and the zoom group positive meniscus lens (3) is 5 to 191.79 mm; the distance L2 between the zoom group first positive meniscus lens (5-2) and the compensation group biconvex lens (6) is 6.8 to 216.48 mm; the distance L3 between the compensation group biconcave lens (7-2) and the rear fixed group positive meniscus lens (8) is 5 to 27.89 mm; and the distance between the rear fixed group second negative meniscus lens (11) and the image plane is 12.29 mm.

4. The 30x short-wave infrared zoom lens according to claim 3, characterized in that: The front fixed group triple cemented lens (1), the front fixed group plano-convex lens (2), the zoom group positive meniscus lens (3), the zoom group negative meniscus lens (4), the zoom group double cemented lens (5), the compensation group double convex lens (6), the compensation group double cemented lens (7), the rear fixed group positive meniscus lens (8), the rear fixed group first negative meniscus lens (9), the rear fixed group double convex lens (10) and the rear fixed group second negative meniscus lens (11) are all made of spherical glass.

5. The 30x short-wave infrared zoom lens according to claim 4, characterized in that: The spherical radius of the three-cemented lens (1) of the front fixed group is 194.34mm, 98.63mm, -196.82mm, and 89.3mm from left to right, respectively; the spherical radius of the left side of the plano-convex lens (2) of the front fixed group is 92.78mm, and the spherical radius of the right side of the plano-convex lens (2) of the front fixed group is infinite; the spherical radius of the left side of the positive meniscus lens (3) of the variable magnification group is 61.68mm, and the spherical radius of the right side of the positive meniscus lens (3) of the variable magnification group is 61.68mm. The surface radius is 235.96mm; the left spherical surface radius of the negative meniscus lens (4) of the zoom group is 90mm, and the right spherical surface radius of the negative meniscus lens (4) of the zoom group is 31.53mm; the spherical surface radius of the double cemented lens (5) of the zoom group is -50.26mm, 22.82mm and 68.62mm from left to right respectively; the left spherical surface radius of the double convex lens (6) of the compensation group is 410.47mm, and the double convex lens (6) of the compensation group is The right spherical radius is -45.25mm; the spherical radius of the double cemented lens (7) of the compensation group is 19.92mm, -18.03mm and 18.87mm from left to right respectively; the left spherical radius of the positive meniscus lens (8) of the rear fixed group is 17.46mm, and the right spherical radius of the positive meniscus lens (8) of the rear fixed group is 49.53mm; the left spherical radius of the first negative meniscus lens (9) of the rear fixed group is 620.37mm, The right side spherical radius of the first negative meniscus lens (9) of the rear fixed group is 21.38 mm; the left side spherical radius of the biconvex lens (10) of the rear fixed group is 49.68 mm, and the right side spherical radius of the biconvex lens (10) of the rear fixed group is -30.86 mm; the left side spherical radius of the second negative meniscus lens (11) of the rear fixed group is -19.75 mm, and the right side spherical radius of the second negative meniscus lens (11) of the rear fixed group is -35.01 mm.

6. The 30x short-wave infrared zoom lens according to claim 5, characterized in that: The thicknesses of the front fixed group negative meniscus lens (1-1), the front fixed group biconvex lens (1-2) and the front fixed group biconcave lens (1-3) are 8 mm, 32 mm and 5 mm respectively; the thickness of the front fixed group plano-convex lens (2) is 16.54 mm; the thickness of the variable magnification group positive meniscus lens (3) is 11.13 mm; the thickness of the variable magnification group negative meniscus lens (4) is 2 mm; the thickness of the variable magnification group biconcave lens (5-1) and the first positive meniscus lens (5-2) of the variable magnification group are 5 mm and 11.0 mm respectively. 7mm; the thickness of the compensation group biconvex lens (6) is 3.74mm; the thickness of the compensation group biconvex lens (7-1) and the compensation group biconcave lens (7-2) are 5.37mm and 3.84mm respectively; the thickness of the rear fixed group positive meniscus lens (8) is 2.93mm; the thickness of the rear fixed group first negative meniscus lens (9) is 2.53mm; the thickness of the rear fixed group biconvex lens (10) is 3.65mm; the thickness of the rear fixed group second negative meniscus lens (11) is 1.58mm.

7. The 30x short-wave infrared zoom lens according to claim 3, characterized in that: In the process from the short focus state to the long focus state, L1 gradually increases, L2 gradually decreases, and L3 gradually increases; in the process from the long focus state to the short focus state, L1 gradually decreases, L2 gradually increases, and L3 gradually decreases.

8. The 30x short-wave infrared zoom lens according to claim 1, characterized in that: The focal length of the front fixed group is 315.66mm; the focal length of the zoom group is -41.7mm; the focal length of the compensation group is 55.56mm; the focal length of the rear fixed group is 203.14mm; and the focal length of the lens is 15mm to 450mm.

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