Short wave infrared zoom lens with laser narrow band filter

Abstract

The present application relates to a kind of short wave infrared zoom lens with laser narrow band filter, the front fixed lens group of lens includes the negative crescent lens A, double convex lens B, positive crescent lens C, negative crescent lens D and positive crescent lens E arranged in sequence from left to right, negative crescent lens A and double convex lens B are tightly formed first cementing group, negative crescent lens D and positive crescent lens E are tightly formed second cementing group;Variable magnification lens group includes the negative crescent lens F, double concave lens G, double convex lens H, double concave lens I arranged in sequence from left to right, double concave lens G and double convex lens H are tightly formed third cementing group;Compensation lens group includes the double convex lens J, negative crescent lens K, double convex lens L, positive crescent lens M arranged in sequence from left to right, negative crescent lens K and double convex lens L are tightly formed fourth cementing group;Back fixed lens group includes the double concave lens N, positive crescent lens O, negative crescent lens P and double convex lens Q arranged in sequence from left to right.The lens helps to realize continuous zooming clear imaging under the night or poor visibility environment.

Description

Technical Field

[0001] This invention relates to a short-wave infrared zoom lens with a laser narrowband filter. Background Technology

[0002] Short-wave infrared lenses offer superior penetration and night vision, providing clearer visual information in low-visibility conditions or at night, helping systems more effectively identify and track targets. Compared to traditional visible light lenses, they offer significant advantages in practical applications such as industrial / agricultural inspection, medical care, security monitoring, and military and safety applications. However, most existing short-wave infrared lenses are fixed-focus lenses, limiting their application scenarios. Summary of the Invention

[0003] The purpose of this invention is to provide a short-wave infrared zoom lens with a laser narrowband filter, which helps to achieve clear imaging during continuous zoom in nighttime or low-visibility environments.

[0004] The technical solution of this invention is as follows: a short-wave infrared zoom lens with a laser narrowband filter, the optical system of which includes a front fixed lens group, a zoom lens group, a compensation lens group, an aperture stop, and a rear fixed lens group arranged sequentially from left to right along the incident light direction; the front fixed lens group includes a negative meniscus lens A, a biconvex lens B, a positive meniscus lens C, a negative meniscus lens D, and a positive meniscus lens E arranged sequentially from left to right, the negative meniscus lens A and the biconvex lens B being closely bonded to form a first cemented group, and the negative meniscus lens D and the positive meniscus lens E being closely bonded to form a second... The lens assembly includes, from left to right, a negative crescent lens F, a biconcave lens G, a biconvex lens H, and a biconcave lens I, with the biconcave lens G and the biconvex lens H closely bonded to form a third cemented assembly; the compensation lens assembly includes, from left to right, a biconvex lens J, a negative crescent lens K, a biconvex lens L, and a positive crescent lens M, with the negative crescent lens K and the biconvex lens L closely bonded to form a fourth cemented assembly; the rear fixed lens assembly includes, from left to right, a biconcave lens N, a positive crescent lens O, a negative crescent lens P, and a biconvex lens Q.

[0005] Furthermore, the air gap between the front fixed lens group and the zoom lens group is 1.8mm-93mm, the air gap between the zoom lens group and the compensating lens group is 124.6mm-1.8mm, and the air gap between the compensating lens group and the rear fixed lens group is 5.2mm-36.7mm.

[0006] Furthermore, the air gap between the first cemented assembly and the positive meniscus lens C is 0.1 mm, the air gap between the positive meniscus lens C and the second cemented assembly is 0.6 mm; the air gap between the negative meniscus lens F and the third cemented assembly is 4.1 mm, and the air gap between the third cemented assembly and the biconcave lens I is 0.8 mm.

[0007] Furthermore, the air gap between the biconvex lens J and the fourth cemented group is 0.1 mm, the air gap between the fourth cemented group and the positive meniscus lens M is 0.3 mm; the air gap between the biconcave lens N and the positive meniscus lens O is 0.1 mm, the air gap between the positive meniscus lens O and the negative meniscus lens P is 21.2 mm, and the air gap between the negative meniscus lens P and the biconvex lens Q is 18.8 mm.

[0008] Furthermore, the biconvex lens B, the meniscus lens E, the meniscus lens L, and the meniscus lens M are all made of ultra-low dispersion optical glass.

[0009] Furthermore, a filter is also provided on the right side of the rear fixed lens group.

[0010] Furthermore, the lens is provided from left to right with a focusing lens barrel, a main lens barrel, a rear lens barrel, and a filter connecting plate for mounting filters. The focusing lens barrel contains a front lens barrel, the main lens barrel contains a zoom slide and a compensation slide, the zoom slide and the compensation slide are respectively provided with zoom lens barrel and compensation lens barrel, and the filter connecting plate is provided with a filter turntable.

[0011] Furthermore, the front fixed lens group, zoom lens group, compensating lens group, and rear fixed lens group are respectively mounted on the front lens barrel, zoom lens barrel, compensating lens barrel, and rear lens barrel.

[0012] Furthermore, the lens also includes an electric focusing mechanism, an electric zoom mechanism, an electric filter switching mechanism, and a detector camera assembly.

[0013] Furthermore, the electric focusing mechanism uses the front fixed lens group as the focusing moving group; the electric zoom mechanism is set on the main lens barrel and drives the zoom lens group and the compensation lens group to perform linear reciprocating motion through the zoom slide and the compensation slide respectively to complete the continuous zoom switching of the lens; the electric filter switching mechanism is connected to the rear lens barrel and controls the rotation of the filter turntable; the detector camera assembly is mounted on the electric filter switching mechanism.

[0014] Compared with existing technologies, the present invention has the following advantages: the short-wave infrared zoom lens achieves continuous zoom throughout the focal length range of 22.3-370mm, enabling wide-range search and tracking of targets, especially for identification and correction in nighttime and low-visibility environments, and can be applied to industrial / agricultural inspection, medical fields, security monitoring, military and security scenarios; a laser narrowband filter is set at the rear of the lens, which broadens the application scenarios. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the lens optical structure of the present invention;

[0016] Figure 2 This is a schematic diagram of the lens mechanical structure of the present invention;

[0017] Figure 3 This is the short-focal-length MTF diagram of the lens of the present invention;

[0018] Figure 4 This is the telephoto MTF diagram of the lens of the present invention;

[0019] Figure 5 This is a schematic cross-sectional view of the electric focusing mechanism of the present invention.

[0020] Figure 6 This is a side view schematic diagram of the electric focusing mechanism of the present invention;

[0021] Figure 7 This is a side view schematic diagram of the electric zoom mechanism of the present invention;

[0022] Figure 8 This is a schematic diagram of the cross-sectional structure of the electric zoom mechanism of the present invention;

[0023] Figure 9 This is a schematic diagram of the structure of the electric filter switching mechanism of the present invention;

[0024] In the diagram: 11-Front fixed lens group; 111-Negative meniscus lens A; 112-Biconvex lens B; 113-Positive meniscus lens C; 114-Negative meniscus lens D; 115-Positive meniscus lens E; 12-Zoom lens group; 121-Negative meniscus lens F; 122-Biconcave lens G; 123-Biconvex lens H; 124-Biconcave lens I; 13-Compensation lens group; 131-Biconvex lens J; 132-Negative meniscus lens K; 133-Biconvex lens L; 134-Plano-convex lens M; 14-Rear fixed lens group; 141-Biconcave lens N; 142-Positive meniscus lens O; 143-Negative meniscus lens P; 144-Biconvex lens Q; 15-Filter ; 151-First filter; 152-Second filter; 16-Electric focusing mechanism; 17-Electric zoom mechanism; 18-Electric filter switching mechanism; 19-Detector camera assembly; 22-Focusing cam retaining ring; 23-Focusing guide pin assembly; 24-Focusing cam; 25-Focusing main lens barrel; 26-Focusing micro switch; 27-Focusing limit pin; 28-Focusing motor gear; 29-Focusing motor; 210-Focusing potentiometer gear; 211-Focusing potentiometer; 32-Magnification slide; 33-Front row steel ball; 34-Magnification guide pin assembly; 35-Magnification cam; 36-Main lens barrel; 37-Rear row steel ball; 38-Magnification cam retaining ring; 310-Compensation carriage; 311-Compensation guide pin assembly; 312-Zoom micro switch; 313-Zoom limit pin; 314-Zoom potentiometer; 315-Zoom motor; 316-Zoom potentiometer gear; 317-Zoom motor gear; 41-Rear assembly connecting plate; 42-Shortwave infrared filter; 43-Filter turntable shaft; 44-Micro switch; 45-Laser narrowband filter; 46-Filter turntable; 47-Filter guide wheel; 48-Filter motor gear; 49-Filter motor. Detailed Implementation

[0025] To make the above features and advantages of the present invention more readily understood, specific embodiments are described below in conjunction with the accompanying drawings, but the present invention is not limited thereto.

[0026] Example 1 (Reference) Figure 1 , Figure 3 and Figure 4

[0027] A short-wave infrared zoom lens with a laser narrowband filter, the lens's optical system comprising a front fixed lens group 11, a zoom lens group 12, a compensating lens group 13, an aperture stop, and a rear fixed lens group 14 arranged sequentially from left to right along the light incident direction; the front fixed lens group 11 includes a negative meniscus lens A111, a biconvex lens B112, a positive meniscus lens C113, a negative meniscus lens D114, and a positive meniscus lens E115 arranged sequentially from left to right, the negative meniscus lens A111 and the biconvex lens B112 being closely bonded to form a first cemented group, and the negative meniscus lens D114 and the positive meniscus lens E115 being closely bonded to form a second cemented group; the zoom lens group 12... The system includes, from left to right, a negative crescent lens F121, a biconcave lens G122, a biconvex lens H123, and a biconcave lens I124, with the biconcave lens G122 and the biconvex lens H123 closely bonded together to form a third cemented group; the compensating lens group includes, from left to right, a biconvex lens J131, a negative crescent lens K132, a biconvex lens L133, and a positive crescent lens M134, with the negative crescent lens K132 and the biconvex lens L133 closely bonded together to form a fourth cemented group; the rear fixing lens group includes, from left to right, a biconcave lens N141, a positive crescent lens O142, a negative crescent lens P143, and a biconvex lens Q144.

[0028] In this embodiment, the air gap between the front fixed lens group 11 and the zoom lens group 12 is 1.8mm-93mm, the air gap between the zoom lens group 12 and the compensation lens group 13 is 124.6mm-1.8mm, and the air gap between the compensation lens group 13 and the rear fixed lens group 14 is 5.2mm-36.7mm.

[0029] In this embodiment, the air gap between the first cemented group and the positive meniscus lens C113 is 0.1 mm, the air gap between the positive meniscus lens C113 and the second cemented group is 0.6 mm, the air gap between the negative meniscus lens F121 and the third cemented group is 4.1 mm, and the air gap between the third cemented group and the biconcave lens I124 is 0.8 mm.

[0030] In this embodiment, the air gap between the biconvex lens J131 and the fourth cemented group is 0.1 mm, and the air gap between the fourth cemented group and the positive meniscus lens M134 is 0.3 mm; the air gap between the biconcave lens N141 and the positive meniscus lens O142 is 0.1 mm, the air gap between the positive meniscus lens O142 and the negative meniscus lens P143 is 21.2 mm, and the air gap between the negative meniscus lens P143 and the biconvex lens Q144 is 18.8 mm.

[0031] In this embodiment, the biconvex lens B112, the meniscus lens E115, the meniscus lens L133, and the meniscus lens M134 are all made of ultra-low dispersion optical glass. By selecting ultra-low dispersion optical glass material, the chromatic aberration of the system is reduced, and the system resolution is improved.

[0032] In this embodiment, a filter 15 is also provided on the right side of the rear fixed lens group 14.

[0033] In this embodiment, the optical system constructed using the aforementioned lenses achieves the following optical properties:

[0034] Focal length: f′min=22.3mm, f′max=370mm;

[0035] Field of view: 1.48°×1.19°~24.3°×19.5°;

[0036] Total optical length ∑L: 258mm;

[0037] Variable stroke: 91.3mm;

[0038] Spectral range: 900nm~1700nm.

[0039] In this embodiment, a positive compensation initial structure is selected during the model selection process. This structure is beneficial for reducing second-order spectral aberrations and improving imaging quality at long focal lengths. The front fixed group uses ultra-low dispersion materials to further reduce second-order spectral aberrations and improve resolution. By selecting high-refractive-index, low-dispersion glass as the material for the positive lens, the curvature of the refractive surface is reduced, which is beneficial for correcting higher-order spherical aberrations at on-axis and off-axis points. The zoom and rear fixed groups are appropriately complicated to reduce image distortion at both long and short focal lengths and to decrease the lead of the motion elements.

[0040] During lens imaging: Light passes from left to right through the first cemented lens group, positive meniscus lens C113, second cemented lens group, negative meniscus lens F121, third cemented lens group, biconcave lens I124, biconvex lens J131, fourth cemented lens group, positive meniscus lens M134, biconcave lens N141, positive meniscus lens O142, negative meniscus lens P143, biconvex lens Q144, and filter 15 before forming an image.

[0041] In this embodiment, the lens parameters of the front fixed lens group 11, the zoom lens group 12, the compensating lens group 13, and the rear fixed lens group 14 are shown in Table 1 below:

[0042] .

[0043] Table 1

[0044] Example 2 (Reference) Figures 1 to 9

[0045] This embodiment, based on Embodiment 1, also includes the mechanical structure of the lens. Specifically: the lens, from left to right, comprises a focusing lens barrel, a main lens barrel, a rear lens barrel, and a filter connecting plate for mounting filters. The focusing lens barrel contains a front lens barrel for mounting the front fixed lens group 11. The main lens barrel contains a zoom slide and a compensation slide. The zoom slide and compensation slide correspondingly house a zoom lens barrel 12 for mounting the zoom lens group and a compensation lens barrel 13 for mounting the compensation lens group. The filter connecting plate has a filter turntable. The rear fixed lens group 14 is mounted on the rear lens barrel.

[0046] In this embodiment, the lens also includes an electric focusing mechanism 16, an electric zoom mechanism 17, an electric filter switching mechanism 18, and a detector camera assembly 19.

[0047] In this embodiment, the electric focusing mechanism 16 uses the front fixed lens group 11 as the focusing moving group. Specifically, see... Figure 5 and Figure 6 The front fixed lens assembly 11 is fitted into the focusing lens barrel 25 after being ground and fitted together. The focusing cam 24 is mounted on the focusing lens barrel 25 via a front precision steel ball 23 and a rear precision steel ball 27, and is pressed tightly by the focusing cam retaining ring 22. The focusing cam 24 is milled with linear oblique grooves according to the optical focusing stroke requirements, and the focusing lens barrel 25 is milled with three equally divided straight grooves. The front fixed lens assembly 11 is connected to the focusing cam 24 and the focusing lens barrel 25 by three 120° evenly distributed focusing guide pin assemblies 23. The focusing motor gear 28 meshes with the gear on the focusing cam 24.

[0048] When the focusing motor 29 is energized and rotates, driving the focusing cam 24 to rotate, the rotational motion of the front fixed lens group 11 is converted into linear motion by the straight groove on the focusing lens barrel 25, thereby achieving focusing on targets at different distances. When focusing on targets at different distances, the focusing potentiometer gear 210 meshes with the focusing motor gear 28, driving the focusing potentiometer 211 shaft to rotate, causing a change in the resistance of the focusing potentiometer 211. The change in the focusing potentiometer 211 can be read through an appropriate sampling circuit and transmitted to the control center, thereby displaying the focusing distance value; conversely, the focusing distance value can be controlled in real time by issuing a command through the control center.

[0049] In this embodiment, the electric zoom mechanism 17 is mounted on the main lens barrel and drives the zoom lens group 12 and the compensation lens group 13 to perform linear reciprocating motion via the zoom slide and the compensation slide, respectively, to complete the continuous zoom switching of the lens.

[0050] Specifically, see Figure 7 and Figure 8The zoom lens assembly 12 is mounted on the zoom slide 32 with screws, forming a zoom component; the compensating lens assembly 13 is mounted on the compensating slide 310 with screws, forming a compensating component. The zoom slide 32 and compensating slide 310 are respectively fitted into the main lens barrel 36 after being ground and fitted. The zoom cam 35 is mounted on the main lens barrel 36 via a front precision steel ball 33 and a rear precision steel ball 37, and is pressed by a zoom cam retainer ring 38, forming a rolling bearing structure. This converts the sliding friction of the zoom cam 35 during rotation into rolling friction, reducing the frictional force during its movement. The zoom cam 35 is milled with zoom and compensating curve grooves according to the requirements of the optical zoom motion equation. Then, the zoom cam 35 is connected to the zoom slide 32 and the compensating slide 310 using the zoom guide pin assembly 34 and the compensating guide pin assembly 311. The zoom motor gear 317 and the zoom potentiometer gear 316 mesh with the zoom cam 35 gear.

[0051] When the rotor of the zoom motor 315 rotates in both positive and negative directions, it causes the precision potentiometer 314 to rotate synchronously with the zoom cam 35. The zoom and compensation curve grooves, along with the zoom guide pin assembly 34 and the compensation guide pin assembly 311, drive the zoom carriage 32 and the compensation carriage 310 to move along the zoom and compensation curve grooves. Two straight grooves on the main lens barrel 36 support the zoom guide pin assembly 34 and the compensation guide pin assembly 311, and convert the rotational motion of the zoom carriage 32 and the compensation carriage 310 into linear motion. Strict control of the fit clearance between the zoom guide pin assembly 34 and the compensation guide pin assembly 311 and the curve grooves of the zoom cam 35 and the straight grooves of the main lens barrel 36 ensures smooth and comfortable sliding of the zoom and compensation components without jamming. In this way, the rotation of the zoom motor 315 enables the zoom and compensation components to move linearly back and forth according to the zoom motion equation, thereby achieving the continuously variable focal length function of the system.

[0052] When the focal length of the system changes, the zoom potentiometer gear 316 meshes with the zoom cam gear 35, causing the precision potentiometer 314 to rotate. This changes the resistance of the precision potentiometer 314. The change in the value of the precision potentiometer 314 can be obtained through an appropriate sampling circuit and transmitted to the control center, thereby displaying the focal length value. Conversely, the focal length can be controlled in real time by issuing a command through the control center.

[0053] In this embodiment, the electric filter switching mechanism is connected to the rear lens barrel, and the electric filter switching mechanism controls the rotation of the filter turntable; the detector camera assembly is mounted on the electric filter switching mechanism.

[0054] Specifically, see Figure 9The electric filter switching mechanism consists of two filters of different specifications (first filter 151 and second filter 152) installed in the filter turntable 46. The filter turntable 46 is fixed to the rear connecting plate 41 via the filter turntable shaft 43, ensuring smooth and unobstructed rotation. The filter motor gear 48 meshes with the gear of the filter turntable 46 via the filter guide wheel 47. When the filter motor 49 is powered on, it drives the filter turntable 46 to rotate. The filter micro switch 44 acts as a limit switch, thereby achieving the cyclic switching requirement between filters of different specifications.

[0055] The above description is only a preferred embodiment of the present invention. For those skilled in the art, designing different forms of short-wave infrared zoom lenses with laser narrowband filters according to the teachings of the present invention does not require creative labor. All equivalent changes, modifications, substitutions and variations made in accordance with the scope of the patent application of the present invention without departing from the principles and spirit of the present invention shall be covered by the present invention.

Claims

1. A short-wave infrared zoom lens with a laser narrowband filter, characterized in that, The lens's optical system consists of a front fixed lens group, a zoom lens group, a compensating lens group, an aperture stop, and a rear fixed lens group, arranged sequentially from left to right along the direction of light incidence. The front fixed lens group comprises, from left to right, a negative meniscus lens A, a biconvex lens B, a positive meniscus lens C, a negative meniscus lens D, and a positive meniscus lens E. Negative meniscus lens A and biconvex lens B are closely bonded to form a first cemented lens group, and negative meniscus lens D and positive meniscus lens E are closely bonded to form a second cemented lens group. The zoom lens group comprises, from left to right, a negative meniscus lens F, a biconcave lens G, a biconvex lens H, and a biconcave lens I. Biconcave lens G and biconvex lens H are closely bonded to form a third cemented lens group. The compensating lens group consists of... The lens group consists of a biconvex lens J, a negative crescent lens K, a biconvex lens L, and a positive crescent lens M arranged sequentially from left to right. The negative crescent lens K and the biconvex lens L are closely joined to form a fourth cemented lens group. The rear fixed lens group consists of a biconcave lens N, a positive crescent lens O, a negative crescent lens P, and a biconvex lens Q arranged sequentially from left to right. The front fixed lens group, the zoom lens group, and the compensating lens group are all movable. The air gap between the front fixed lens group and the zoom lens group is 1.8mm-93mm, the air gap between the zoom lens group and the compensating lens group is 124.6mm-1.8mm, and the air gap between the compensating lens group and the rear fixed lens group is 5.2mm-36.7mm.

2. The short-wave infrared zoom lens with a laser narrowband filter according to claim 1, characterized in that, The air gap between the first cemented assembly and the positive meniscus lens C is 0.1 mm, the air gap between the positive meniscus lens C and the second cemented assembly is 0.6 mm, the air gap between the negative meniscus lens F and the third cemented assembly is 4.1 mm, and the air gap between the third cemented assembly and the biconcave lens I is 0.8 mm.

3. A short-wave infrared zoom lens with a laser narrowband filter according to claim 2, characterized in that, The air gap between the biconvex lens J and the fourth cemented group is 0.1 mm, and the air gap between the fourth cemented group and the positive meniscus lens M is 0.3 mm; the air gap between the biconcave lens N and the positive meniscus lens O is 0.1 mm, the air gap between the positive meniscus lens O and the negative meniscus lens P is 21.2 mm, and the air gap between the negative meniscus lens P and the biconvex lens Q is 18.8 mm.

4. A short-wave infrared zoom lens with a laser narrowband filter according to claim 1 or 3, characterized in that, The biconvex lens B, the meniscus lens E, the meniscus lens L, and the meniscus lens M are all made of ultra-low dispersion optical glass.

5. A short-wave infrared zoom lens with a laser narrowband filter according to claim 1, characterized in that, A filter is also located on the right side of the rear fixed lens group.

6. A short-wave infrared zoom lens with a laser narrowband filter according to claim 1, 3, or 5, characterized in that, The lens has a focusing lens barrel, a main lens barrel, a rear lens barrel, and a filter connecting plate for mounting filters, arranged from left to right. The focusing lens barrel has a front lens barrel inside, the main lens barrel has a zoom slide and a compensation slide, and the zoom slide and compensation slide are respectively equipped with zoom lens barrel and compensation lens barrel. The filter connecting plate is equipped with a filter turntable.

7. A short-wave infrared zoom lens with a laser narrowband filter according to claim 6, characterized in that, The front fixed lens group, zoom lens group, compensating lens group, and rear fixed lens group are respectively installed on the front lens barrel, zoom lens barrel, compensating lens barrel, and rear lens barrel.

8. A short-wave infrared zoom lens with a laser narrowband filter according to claim 6, characterized in that, The lens also includes an electric focusing mechanism, an electric zoom mechanism, an electric filter switching mechanism, and a detector camera assembly.

9. A short-wave infrared zoom lens with a laser narrowband filter according to claim 8, characterized in that, The electric focusing mechanism uses the front fixed lens group as the focusing moving group; the electric zoom mechanism is set on the main lens barrel and drives the zoom lens group and the compensation lens group to perform linear reciprocating motion through the zoom slide and the compensation slide respectively to complete the continuous zoom switching of the lens; the electric filter switching mechanism is connected to the rear lens barrel and controls the rotation of the filter turntable; the detector camera assembly is mounted on the electric filter switching mechanism.

Images