Short-wave infrared zoom lens with laser narrow-band filter

Abstract

The invention relates to a short-wave infrared zoom lens with a laser narrow-band filter. A front fixed lens group of the lens comprises 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. The negative meniscus lens A and the biconvex lens B are closely connected to form a first glued group. The negative meniscus lens D and the positive meniscus lens E are tightly connected to form a second gluing group; the zoom lens group comprises a negative meniscus lens F, a biconcave lens G, a biconvex lens H and a biconcave lens I which are sequentially arranged from left to right; the biconcave lens G and the biconvex lens H are closely connected to form a third gluing group; the compensating lens group comprises a biconvex lens J, a negative meniscus lens K and a biconvex lens L which are sequentially arranged from left to right, and the positive meniscus lens M, the negative meniscus lens K and the biconvex lens L are closely connected to form a fourth gluing group; and the rear fixed lens group comprises a biconcave lens N, a positive meniscus lens O, a negative meniscus lens P and a biconvex lens Q which are sequentially arranged from left to right. The lens is helpful for realizing continuous zooming and clear imaging at night or in an environment with poor visibility.

Description

Technical Field

[0001] The invention relates to a short-wave infrared zoom lens with a laser narrow-band filter. Background Art

[0002] Short-wave infrared lenses have better penetration and night vision effects. At night or in poor visibility environments, they can provide clearer visual information, helping the system to more effectively identify and track targets. Compared with traditional visible light lenses, they have greater advantages in practical application scenarios such as industrial / agricultural detection, medical fields, security monitoring, military and security. However, most existing short-wave infrared lenses are fixed-focus lenses, which limits their application scenarios. Summary of the invention

[0003] The object of the present invention is to provide a short-wave infrared zoom lens with a laser narrow-band filter, which helps to achieve continuous zoom and clear imaging at night or in an environment with poor visibility.

[0004] The technical solution of the present invention is: a short-wave infrared zoom lens with a laser narrow-band filter, the optical system of the lens comprises a front fixed lens group, a magnification lens group, a compensation lens group, an aperture and a rear fixed lens group arranged in sequence from left to right along the incident direction of light; the front fixed lens group comprises 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 in sequence from left to right, the negative meniscus lens A and the biconvex lens B are closely connected to form a first cemented group, the negative meniscus lens D and the positive meniscus lens E are closely connected to form a second The zoom lens group includes a negative meniscus lens F, a biconcave lens G, a biconvex lens H, and a biconcave lens I, which are sequentially arranged from left to right, and the biconcave lens G and the biconvex lens H are closely connected to form a third cemented group; the compensation lens group includes a biconvex lens J, a negative meniscus lens K, a biconvex lens L, and a positive meniscus lens M, which are sequentially arranged from left to right, and the negative meniscus lens K and the biconvex lens L are closely connected to form a fourth cemented group; the rear fixed lens group includes a biconcave lens N, a positive meniscus lens O, a negative meniscus lens P, and a biconvex lens Q, which are sequentially arranged from left to right.

[0005] Furthermore, the air space between the front fixed lens group and the variable power lens group is 1.8mm-93mm, the air space between the variable power lens group and the compensation lens group is 124.6mm-1.8mm, and the air space between the compensation lens group and the rear fixed lens group is 5.2mm-36.7mm.

[0006] Furthermore, the air gap between the first bonding group and the positive meniscus lens C is 0.1 mm, and the air gap between the positive meniscus lens C and the second bonding group is 0.6 mm; the air gap between the negative meniscus lens F and the third bonding group is 4.1 mm, and the air gap between the third bonding group 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 positive meniscus lens E, the positive meniscus lens L, and the positive meniscus lens M are all made of ultra-low dispersion optical glass.

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

[0010] Furthermore, the lens is provided with a focusing barrel, a main barrel, a rear group barrel and a filter connecting plate for installing filters from left to right, the front group barrel is provided inside the focusing barrel, the magnification slide and the compensation slide are provided inside the main barrel, the magnification slide and the compensation slide are correspondingly provided with a magnification barrel and a compensation barrel, and a filter turntable is provided on the filter connecting plate.

[0011] Furthermore, the front fixed lens group, the variable-power lens group, the compensating lens group and the rear fixed lens group are correspondingly mounted on the front lens barrel, the variable-power lens barrel, the compensating lens barrel and the 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 selects a front fixed lens group as a focusing movable group; the electric zoom mechanism is arranged 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 the electric filter switching mechanism controls the rotation of the filter turntable; the detector camera assembly is installed on the electric filter switching mechanism.

[0014] Compared with the prior art, the present invention has the following advantages: the short-wave infrared zoom lens realizes continuous zoom of the focal length of 22.3-370mm throughout the entire range, can perform large-scale search and tracking photography of targets, especially identification and correction at night and in low-visibility environments, and is applied to industrial / agricultural detection, medical fields, security monitoring, military and safety and other demand scenarios; a laser narrow-band filter is arranged at the rear end of the lens, which broadens the application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the optical structure of the lens of the present invention; Figure 2 It is a schematic diagram of the mechanical structure of the lens of the present invention; Figure 3 is a short-focus MTF diagram of the lens of the present invention; Figure 4 is a telephoto MTF diagram of the lens of the present invention; Figure 5 It is a schematic diagram of the cross-sectional structure of the electric focusing mechanism of the present invention; Figure 6 It is a schematic diagram of the side view structure of the electric focusing mechanism of the present invention; Figure 7 It is a schematic diagram of the side view structure of the electric zoom mechanism of the present invention; Figure 8 It is a schematic diagram of the cross-sectional structure of the electric zoom mechanism of the present invention; Fig. 9 It is a schematic diagram of the structure of the electric filter switching mechanism of the present invention; In the figure: 11-front fixed lens group; 111-negative crescent lens A; 112-double convex lens B; 113-positive crescent lens C; 114-negative crescent lens D; 115 positive crescent lens E; 12-variable lens group; 121-negative crescent lens F; 122-double concave lens G; 123-double convex lens H; 124-double concave lens I; 13-compensating lens group; 131-double convex lens J; 132-negative crescent lens K; 133-double convex lens L; 134-plano-convex lens M; 14-rear fixed lens group; 141-double concave lens N; 142-positive crescent lens O; 143-negative crescent lens P; 144-double convex 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 pressure 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-zooming slide;33-front steel balls;34-zooming guide pin assembly;35-zooming cam;36-main lens barrel;37-rear steel balls;38-zooming cam pressure ring; 310-compensation slide; 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 group connecting plate; 42-short-wave infrared filter; 43-filter turntable shaft; 44-micro switch; 45-laser narrowband filter; 46-filter turntable; 47-filter wheel; 48-filter motor gear; 49-filter motor. DETAILED DESCRIPTION

[0016] In order to make the above features and advantages of the present invention more easily understood, embodiments are given below with reference to the accompanying drawings for detailed description, but the present invention is not limited thereto.

[0017] Example 1 Reference Figure 1 , Figure 3 and Figure 4 A short-wave infrared zoom lens with a laser narrowband filter, the optical system of the lens comprises a front fixed lens group 11, a zoom lens group 12, a compensation lens group 13, an aperture and a rear fixed lens group 14 arranged in sequence from left to right along the incident direction of light; the front fixed lens group 11 comprises 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 in sequence from left to right, the negative meniscus lens A111 and the biconvex lens B112 are closely connected to form a first cemented group, and the negative meniscus lens D114 and the positive meniscus lens E115 are closely connected to form a second cemented group; the zoom lens group 12 It includes a negative meniscus lens F121, a biconcave lens G122, a biconvex lens H123, and a biconcave lens I124, which are arranged in sequence from left to right, and the biconcave lens G122 and the biconvex lens H123 are closely connected to form a third cemented group; the compensation lens group includes a biconvex lens J131, a negative meniscus lens K132, a biconvex lens L133, and a positive meniscus lens M134, which are arranged in sequence from left to right, and the negative meniscus lens K132 and the biconvex lens L133 are closely connected to form a fourth cemented group; the rear fixed lens group includes a biconcave lens N141, a positive meniscus lens O142, a negative meniscus lens P143 and a biconvex lens Q144, which are arranged in sequence from left to right.

[0018] 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.

[0019] In this embodiment, the air gap between the first bonding group and the positive meniscus lens C113 is 0.1 mm, and the air gap between the positive meniscus lens C113 and the second bonding group is 0.6 mm; the air gap between the negative meniscus lens F121 and the third bonding group is 4.1 mm, and the air gap between the third bonding group and the biconcave lens I124 is 0.8 mm.

[0020] In this embodiment, the air gap between the biconvex lens J131 and the fourth bonding group is 0.1 mm, and the air gap between the fourth bonding 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.

[0021] In this embodiment, the biconvex lens B112, the positive crescent lens E115, the positive crescent lens L133, and the positive crescent lens M134 are all made of ultra-low dispersion optical glass. By selecting ultra-low dispersion optical glass materials, the chromatic aberration of the system is reduced and the system resolution is improved.

[0022] In this embodiment, a filter 15 is further disposed on the right side of the rear fixed lens group 14 .

[0023] In this embodiment, the optical system formed by the above lenses achieves the following optical indicators: Focal length: f′min=22.3mm, f′max=370mm; Field of view: 1.48°×1.19°~24.3°×19.5°; Total optical length ∑L: 258mm; Zoom stroke: 91.3mm; Spectral range: 900nm~1700nm.

[0024] In this embodiment, the initial structure of the positive group compensation is selected during the selection process. This structure is conducive to reducing the system's secondary spectral aberrations and improving the imaging quality at long focus. The ultra-low dispersion material is used in the front fixed group to further reduce the system's secondary spectral aberrations and improve the resolution level; by selecting high refractive index and low dispersion glass as the material of the positive lens, the curvature of the refractive surface is reduced, which is beneficial to correcting the high-level spherical aberration of the on-axis point and the off-axis point. The zoom group and the rear fixed group are appropriately complicated to reduce the image distortion of long focus and short focus, and reduce the lead of the moving element.

[0025] When the lens forms an image: the light passes from left to right through the first cemented group, positive meniscus lens C113, the second cemented group, negative meniscus lens F121, the third cemented group, biconcave lens I124, biconvex lens J131, the fourth cemented group, positive meniscus lens M134, biconcave lens N141, positive meniscus lens O142, negative meniscus lens P143, biconvex lens Q144, and filter 15 to form an image.

[0026] In this embodiment, the parameters of the lenses of the front fixed lens group 11, the variable magnification lens group 12, the compensation lens group 13 and the rear fixed lens group 14 are shown in the following Table 1: .

[0027] Table 1 Example 2 Reference Figures 1 to 9 This embodiment further includes a mechanical structure of the lens on the basis of the first embodiment. Specifically, the lens is provided with a focusing lens barrel, a main lens barrel, a rear lens barrel, and a filter connecting plate for installing filters in sequence from left to right. The front lens barrel for installing the front fixed lens group 11 is provided inside the focusing lens barrel, and a zoom slide and a compensation slide are provided inside the main lens barrel. The zoom slide and the compensation slide are provided with a zoom lens barrel 12 for installing the zoom lens group and a compensation lens barrel 13 for installing the compensation lens group, respectively. The filter connecting plate is provided with a filter rotating disk. The rear fixed lens group 14 is installed on the rear lens barrel.

[0028] In this embodiment, the lens further includes an electric focusing mechanism 16 , an electric zoom mechanism 17 , an electric filter switching mechanism 18 and a detector camera assembly 19 .

[0029] In this embodiment, the electric focusing mechanism 16 uses the front fixed lens group 11 as the focusing moving group. Figure 5 and Figure 6 The front fixed lens group 11 is installed in the focusing lens barrel 25 after being ground and matched with the focusing lens barrel 25. The focusing cam 24 is installed on the focusing lens barrel 25 through the front precision steel ball 23 and the rear precision steel ball 27, and is pressed by the focusing cam pressing ring 22. The focusing cam 24 is milled with a linear inclined groove according to the requirements of the optical focusing stroke, and the focusing lens barrel 25 is milled with a straight groove divided into three equal parts; the front fixed lens group 11 is connected with the focusing cam 24 and the focusing lens barrel 25 by three focusing guide pin assemblies 23 evenly distributed at 120°, and the focusing motor gear 28 is meshed with the gear on the focusing cam 24.

[0030] When the focus motor 29 is powered on and rotates, driving the focus cam 24 to rotate, the rotational motion of the front fixed lens group 11 is converted into linear motion through the restriction of the straight groove on the focus lens barrel 25, thereby realizing the focus of the near and far targets. When focusing on the near and far targets, the focus potentiometer gear 210 drives the focus potentiometer 211 shaft to rotate by meshing with the focus motor gear 28, so that the resistance value of the focus potentiometer 211 changes. The change value of the focus potentiometer 211 can be read out through an appropriate sampling circuit and transmitted to the control center, thereby realizing the display of the focus distance value; conversely, by giving a command through the control center, the real-time control of the focus distance value can be realized.

[0031] In this embodiment, the electric zoom mechanism 17 is disposed on the main lens barrel, and drives the zoom lens group 12 and the compensating lens group 13 to perform linear reciprocating motion via the zoom slide and the compensating slide to complete continuous zoom switching of the lens.

[0032] Specifically, see Figure 7 and Figure 8 The zoom lens group 12 is installed on the zoom slide 32 by screws to form a zoom assembly; the compensation lens group 13 is installed on the compensation slide 310 by screws to form a compensation assembly. The zoom slide 32 and the compensation slide 310 are respectively installed in the main lens barrel 36 after grinding and matching with the main lens barrel 36. The zoom cam 35 is installed on the main lens barrel 36 through the front precision steel ball 33 and the rear precision steel ball 37, and is pressed by the zoom cam pressing ring 38 to form a rolling bearing structure, which converts the sliding friction when the zoom cam 35 rotates into rolling friction to reduce the friction force when the zoom cam 35 moves. The zoom cam 35 is milled with zoom and compensation curve grooves according to the requirements of the optical zoom motion equation, and then the zoom cam 35 is connected with the zoom slide 32 and the compensation slide 310 by the zoom guide pin assembly 34 and the compensation guide pin assembly 311. The zoom motor gear 317 and the zoom potentiometer gear 316 are respectively engaged with the zoom cam 35 gear.

[0033] When the rotor of the zoom motor 315 performs positive and negative rotational motion, the precision potentiometer 314 and the zoom cam 35 rotate synchronously. The zoom slide 32 and the compensation slide 310 are driven to move according to the zoom and compensation curve grooves through the zoom and compensation curve grooves and the zoom guide pin assembly 34 and the compensation guide pin assembly 311. The two straight grooves on the main lens barrel 36 play the role of supporting the zoom guide pin assembly 34 and the compensation guide pin assembly 311, and convert the rotational motion of the zoom slide 32 and the compensation slide 310 into linear motion. The matching clearance between the zoom guide pin assembly 34 and the compensation guide pin assembly 311 and the curved groove of the zoom cam 35 and the linear groove of the main lens barrel 36 is strictly controlled to ensure that the zoom and compensation components slide smoothly and comfortably without jamming. In this way, the zoom motor 315 rotates to realize the zoom assembly and the compensation assembly to make forward and backward linear motion according to the zoom motion equation, thereby realizing the continuous variable function of the system focal length.

[0034] When the focal length of the system changes, the zoom potentiometer gear 316 meshes with the zoom cam 35 gear to rotate the precision potentiometer 314, and the resistance value of the precision potentiometer 314 changes. The change value of the precision potentiometer 314 can be taken out through an appropriate sampling circuit and transmitted to the control center, thereby realizing the display of the focal length value; conversely, by giving commands through the control center, real-time control of the focal length can be realized.

[0035] 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 installed on the electric filter switching mechanism.

[0036] Specifically, see Fig. 9 , Electric filter switching mechanism: Two filters of different specifications (first filter 151, second filter 152) are loaded into the filter turntable 46, and the filter turntable 46 is fixed to the rear group connecting plate 41 through the filter turntable shaft 43 to ensure that the filter turntable 46 rotates smoothly without jamming. The filter motor gear 48 is meshed with the filter turntable 46 gear through the filter wheel 47. When the filter motor 49 is powered on, it drives the filter turntable 46 to rotate, and the filter micro switch 44 plays a limiting role, thereby realizing the cyclic switching requirements between filters of different specifications.

[0037] The above description is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, it does not require creative labor to design different forms of short-wave infrared zoom lenses with laser narrow-band filters. Without departing from the principles and spirit of the present invention, all equal changes, modifications, substitutions and variations made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A short-wave infrared zoom lens with a laser narrow-band filter, characterized in that: The optical system of the lens comprises a front fixed lens group, a zoom lens group, a compensating lens group, an aperture and a rear fixed lens group which are arranged in sequence from left to right along the incident direction of light; the front fixed lens group comprises 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 which are arranged in sequence from left to right, the negative meniscus lens A and the biconvex lens B are closely connected to form a first cemented group, the negative meniscus lens D and the positive meniscus lens E are closely connected to form a second cemented group; the zoom lens group comprises 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 which are arranged in sequence from left to right A negative meniscus lens F, a biconcave lens G, a biconvex lens H, and a biconcave lens I are arranged in sequence, and the biconcave lens G and the biconvex lens H are closely connected to form a third cemented group; the compensation lens group includes a biconvex lens J, a negative meniscus lens K, a biconvex lens L, and a positive meniscus lens M arranged in sequence from left to right, and the negative meniscus lens K and the biconvex lens L are closely connected to form a fourth cemented group; the rear fixed lens group includes a biconcave lens N, a positive meniscus lens O, a negative meniscus lens P, and a biconvex lens Q arranged in sequence from left to right.

2. The short-wave infrared zoom lens with a laser narrow-band filter according to claim 1, characterized in that: The air space between the front fixed lens group and the variable magnification lens group is 1.8mm-93mm, the air space between the variable magnification lens group and the compensation lens group is 124.6mm-1.8mm, and the air space between the compensation lens group and the rear fixed lens group is 5.2mm-36.7mm.

3. A short-wave infrared zoom lens with a laser narrow-band filter according to claim 1 or 2, characterized in that: The air gap between the first bonding group and the positive meniscus lens C is 0.1 mm, and the air gap between the positive meniscus lens C and the second bonding group is 0.6 mm; the air gap between the negative meniscus lens F and the third bonding group is 4.1 mm, and the air gap between the third bonding group and the biconcave lens I is 0.8 mm.

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

5. A short-wave infrared zoom lens with a laser narrow-band filter according to claim 1, 2 or 4, characterized in that: The biconvex lens B, the positive meniscus lens E, the positive meniscus lens L and the positive meniscus lens M are all made of optical glass with ultra-low dispersion.

6. The short-wave infrared zoom lens with a laser narrow-band filter according to claim 1, characterized in that: A filter is also arranged on the right side of the rear fixed lens group.

7. A short-wave infrared zoom lens with a laser narrow-band filter according to claim 1, 2, 4 or 6, characterized in that: The lens is provided with a focusing barrel, a main barrel, a rear barrel and a filter connecting plate for installing filters from left to right. The front barrel is provided inside the focusing barrel, and a zoom slide and a compensation slide are provided inside the main barrel. The zoom slide and the compensation slide are provided with a zoom barrel and a compensation barrel respectively, and a filter turntable is provided on the filter connecting plate.

8. The short-wave infrared zoom lens with a laser narrow-band filter according to claim 7, characterized in that: The front fixed lens group, the variable magnification lens group, the compensating lens group and the rear fixed lens group are correspondingly mounted on the front lens barrel, the variable magnification lens barrel, the compensating lens barrel and the rear lens barrel.

9. The short-wave infrared zoom lens with a laser narrow-band filter according to claim 7, 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.

10. The short-wave infrared zoom lens with a laser narrow-band filter according to claim 9, characterized in that: The electric focusing mechanism uses a front fixed lens group as a focusing movable group; the electric zoom mechanism is arranged on the main lens barrel, and drives the zoom lens group and the compensation lens group to perform linear reciprocating motion respectively through the zoom slide and the compensation slide to complete the continuous zoom switching of the lens; 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 installed on the electric filter switching mechanism.

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