Wide temperature range large target surface high definition dual-band lens

Abstract

The application provides a wide-temperature-range large-target high-definition double-band lens, which first relies on a focusing group movable along an optical axis, can effectively compensate for optical deviation caused by temperature deformation, and ensures that the equipment always maintains stable image surface under a wide temperature environment of-55 DEG C to 85 DEG C and a close-range shooting working condition. Meanwhile, the filter group assembled on the wheel type switching mechanism can rotate and switch different functional filters according to the use requirement, can not only perform optical filtering and polarization processing on the incident light, but also can quickly switch various imaging modes, and fully meets the use requirement of various differentiated and complicated imaging scenes. In addition, the focusing group and the rear fixed group form optical cooperation and cooperative operation, and can comprehensively guarantee that the wide-temperature-range large-target high-definition double-band lens presents high-quality high-definition double-band imaging effect under the large-target specification.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic technology, and in particular to a wide-temperature-range, large-surface, high-definition dual-band lens. Background Technology

[0002] Optical lenses, as core components of photoelectric detection systems, are widely used in machine vision, security monitoring, vehicle recording, drone detection, and industrial inspection. As downstream applications continue to demand higher lens performance, the market's need for fixed-focus lenses with large target surface adaptability, wide operating temperature range, day and night observation capability, and high image quality is becoming increasingly urgent.

[0003] Currently, conventional fixed-focus lenses have many technical shortcomings in practical applications, making it difficult to meet the needs of high-end imaging scenarios. These shortcomings are mainly reflected in the following aspects: First, balancing large sensor size adaptation with visual appeal is difficult. Large sensor sizes offer advantages in high resolution and wide field of view, but increase the difficulty of lens design and assembly. When adapting to large sensor sizes, traditional lenses often experience problems such as increased edge field-of-view aberration, severe illuminance attenuation, and reduced color reproduction, making it difficult to achieve both high definition and uniformity across the entire field of view. Second, poor stability over a wide temperature range. When working in high and low temperature environments, due to thermal expansion of optical materials, changes in refractive index, and deformation of mechanical structures, lenses are prone to thermal defocusing and image plane drift in extremely high and low temperature environments, resulting in a significant decrease in image clarity. This makes it difficult to meet the long-term reliable operation requirements in extreme temperature environments such as field, vehicle-mounted, and airborne applications. Third, to meet day and night observation capabilities, lenses need to switch filters, making it difficult to simultaneously achieve high-definition imaging in both visible and near-infrared bands over a wide temperature range.

[0004] Therefore, there is an urgent need for a wide-temperature-range, large-area, high-definition dual-band lens to solve the above technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a wide-temperature-range, large-target-area, high-definition dual-band lens that solves the problem that traditional lenses cannot achieve simultaneous high-definition imaging of visible light and near-infrared dual bands in a wide-temperature-range environment. It can be adapted to large-target-area detectors, supports day and night observation, and has stable and excellent image quality across the entire field of view and temperature range.

[0006] To achieve the above objectives, the present invention provides a wide temperature range, large target surface, high-definition dual-band lens, comprising a focusing group, a filter group, and a rear fixing group arranged sequentially along the incident light direction; the filter group is mounted on a wheel-type switching mechanism and is equipped with multiple filters adapted to different imaging scenarios for optical filtering or polarization processing of incident light. The focusing group is movable along the optical axis to keep the image plane stable in a wide temperature range and close-up working environment with a large target area. The wheel-type switching mechanism is used to drive the filter to rotate, so that a single filter can be selectively connected to the optical axis to complete the switching of different imaging modes. The rear fixed group works in conjunction with the focusing group to achieve high-definition dual-band imaging in a wide temperature range and with a large target area.

[0007] Preferably, the optical elements in the focusing group and the rear fixing group are all spherical mirrors, and both adopt non-cemented lens structures.

[0008] Preferably, the focusing group includes a first biconvex lens, a first meniscus lens, a second biconvex lens, and a first biconcave lens arranged sequentially along the incident direction of light. The air gap between the first biconvex lens and the first meniscus lens is 0.25–0.35 mm, the air gap between the first meniscus lens and the second biconvex lens is 0.6–0.7 mm, and the air gap between the second biconvex lens and the first biconcave lens is 0.6–0.7 mm.

[0009] Preferably, the rear fixing group includes a second biconcave lens, a third biconvex lens, and a fourth biconvex lens arranged sequentially along the incident direction of light. The air gap between the second biconcave lens and the third biconvex lens is 0.45–0.55 mm, and the air gap between the third biconvex lens and the fourth biconvex lens is 9.5–10.5 mm.

[0010] Preferably, the filter is selected from one of a visible light filter, a near-infrared filter, a narrow band filter, and a polarizing filter; the air gap between the first biconcave lens and the filter located on the optical axis is 40-50 mm, and the air gap between the filter located on the optical axis and the second biconcave lens is 5-7 mm.

[0011] Preferably, the refractive index and Abbe number of the optical elements in the focusing group, filter group, and rear fixing group satisfy the following conditions: 1.45<n1<1.55, 75<V1<85; 1.6<n2<1.7, 55<V2<65; 1.45<n3<1.55, 75<V3<85; 1.7<n4<1.8, 45<V4<55; 1.45<n5<1.55, 60<V5<70; 1.55<n6<1.65, 60<V6<70; 1.45<n7<1.55, 65<V7<75; 1.6<n8<1.7, 30<V8<40; Wherein, n1, n2, n3, n4, n5, n6, n7, and n8 are the refractive indices of the first biconvex lens, the first meniscus lens, the second biconvex lens, the first biconcave lens, the filter, the second biconcave lens, the third biconvex lens, and the fourth biconvex lens, respectively; and V1, V2, V3, V4, V5, V6, V7, and V8 are the Abbe numbers of the first biconvex lens, the first meniscus lens, the second biconvex lens, the first biconcave lens, the filter, the second biconcave lens, the third biconvex lens, and the fourth biconvex lens, respectively.

[0012] Preferably, the focal length f1 of the first biconvex lens is: 69mm < f1 < 77mm; the focal length f2 of the first meniscus lens is: -86mm < f2 < -77mm; the focal length f3 of the second biconvex lens is: 38mm < f3 < 43mm; the focal length f4 of the first biconcave lens is: -58mm < f4 < -52mm; the focal length f6 of the second biconcave lens is: -19.7mm < f6 < -17.8mm; the focal length f7 of the third biconvex lens is: 39mm < f7 < 43.5mm; and the focal length f8 of the fourth biconvex lens is: 65mm < f8 < 72.2mm.

[0013] Preferably, the wheel-type switching mechanism includes a filter gear and a filter wheel seat. The filter gear is fixed to the middle end of the lens tube of the wide temperature range, large target surface, high-definition dual-band lens through the filter wheel seat. The filter gear drives the filter wheel seat to rotate, and multiple filters are fixedly installed on the filter wheel seat.

[0014] Preferably, the optical system parameters of the wide temperature range, large target surface, high-definition dual-band lens are as follows: operating wavelengths of 420nm~650nm, 700nm~900nm and 1064nm, focal length of 142.48mm, total optical length of 108mm, field of view of 5.76°×5.76°, aperture of 30mm, and optical distortion ≤0.87%; operating temperature range of -55~85℃, near-field measurement distance of 10m; compatible imaging target surface size of 4096×4096, single pixel size of 3.5μm, and lens diagonal image height of 22mm.

[0015] Preferably, when the wide-temperature-range, large-area, high-definition dual-band lens operates in an environment of -55℃, the focusing group moves axially 0.27mm closer to the image plane; when the wide-temperature-range, large-area, high-definition dual-band lens operates in an environment of 85℃, the focusing group moves axially 0.28mm further away from the image plane; when the wide-temperature-range, large-area, high-definition dual-band lens observes a 10m close-up target, the focusing group moves axially 0.79mm further away from the image plane.

[0016] The beneficial effects of this invention are as follows: Unlike existing technologies, this invention provides a wide-temperature-range, large-aperture, high-definition dual-band lens. Firstly, relying on a focusing group that can move along the optical axis, it effectively compensates for optical deviations caused by temperature deformation, ensuring image plane stability in a wide temperature range of -55℃ to 85℃ and in close-up shooting conditions. Simultaneously, the filter group mounted on the wheel-type switching mechanism can rotate and switch between filters with different functions according to usage requirements. This not only performs optical filtering and polarization processing on incident light but also allows for rapid switching between multiple imaging modes, fully meeting the requirements of various differentiated and complex imaging scenarios. Furthermore, the focusing group and the rear fixing group work together optically to comprehensively ensure that the wide-temperature-range, large-aperture, high-definition dual-band lens delivers excellent high-definition dual-band imaging effects even with a large aperture. Attached Figure Description

[0017] Figure 1 The optical system structure diagram of the wide temperature range, large target surface, high-definition dual-band lens provided by the present invention; Figure 2 This is a diagram of the optical-mechanical structure of the wide-temperature-range, large-target-area, high-definition dual-band lens provided in Embodiment 1. Figure 3 A room temperature dot plot of the visible light band of the wide temperature range, large target surface, high-definition dual-band lens provided in this embodiment 1; Figure 4 The visible light band room temperature transfer function diagram of the wide temperature range large target area high-definition dual-band lens provided in this embodiment 1; Figure 5 The visible light field curvature / distortion diagram of the wide temperature range, large target surface, high-definition dual-band lens provided in this embodiment 1; Figure 6 A near-infrared band room temperature dot plot of the wide temperature range large target area high-definition dual-band lens provided in this embodiment 1; Figure 7 The near-infrared band room temperature transfer function diagram of the wide temperature range large target area high-definition dual-band lens provided in this embodiment 1; Figure 8 The near-infrared field curvature / distortion diagram of the wide temperature range, large target area, high-definition dual-band lens provided in this embodiment 1; Figure 9 A point diagram at -55°C in the visible light band for the wide temperature range, large target area, high-definition dual-band lens provided in Embodiment 1. Figure 10 The transfer function of the wide temperature range, large target area, high-definition dual-band lens provided in this embodiment 1 at -55℃ in the visible light band; Figure 11 A point diagram at -55°C in the near-infrared band for the wide temperature range, large target area, high-definition dual-band lens provided in Embodiment 1. Figure 12The transfer function of the wide-temperature-range, large-target-area, high-definition dual-band lens provided in Embodiment 1 at -55℃ in the near-infrared band; Figure 13 A dot plot of the wide temperature range, large target area, high-definition dual-band lens provided in this embodiment at 85°C in the visible light band; Figure 14 The transfer function of the wide temperature range, large target area, high-definition dual-band lens provided in this embodiment 1 at 85°C in the visible light band; Figure 15 A dot plot of the wide-temperature-range, large-target-area, high-definition dual-band lens provided in Embodiment 1 at 85°C in the near-infrared band; Figure 16 The transfer function of the wide-temperature-range, large-target-area, high-definition dual-band lens provided in Embodiment 1 at 85°C in the near-infrared band. Figure 17 The following are images showing close-up observations at 10m in the visible light band using the wide-temperature-range, large-surface, high-definition dual-band lens provided in Embodiment 1. Figure 18 The transfer function graph of the wide temperature range, large target surface, high-definition dual-band lens provided in this embodiment 1 when observing a close-up scene of 10m in the visible light band. Figure 19 A series of images showing close-up observations at 10m in the near-infrared band using the wide-temperature-range, large-target-area, high-definition dual-band lens provided in Embodiment 1. Figure 20 The transfer function graph of the wide temperature range, large target surface, high-definition dual-band lens provided in this embodiment 1 when observing a close-up scene of 10m in the near-infrared band; In the accompanying drawings: 10—Focusing group; 101—First biconvex lens; 102—First meniscus lens; 103—Second biconvex lens; 104—First biconcave lens; 20—Filter group; 201—Filter; 30—Rear fixing group; 301—Second biconcave lens; 201—Third biconvex lens; 303—Fourth biconvex lens; 401—Front objective lens retaining ring; 402—First spacer; 403—Second spacer; 404—First retaining ring; 405—Objective lens frame; 406—Third spacer; 407—Fourth spacer; 408—Focusing lens frame; 409—Lens tube; 410—Filter gear; 411—Filter wheel seat; 412—Rear lens frame; 413—Fifth spacer; 414—Second retaining ring; 415—Sixth spacer; 416—Seventh spacer; 417—Rear retaining ring. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] To address the shortcomings of existing lenses, such as poor wide-temperature-range adaptability, limited imaging modes, and unsatisfactory dual-band imaging performance with large target surfaces, this invention provides a wide-temperature-range, large-target-area, high-definition dual-band lens. It achieves temperature variation compensation and near-field image stabilization through a movable focusing group, expands multiple imaging modes with a wheeled switching filter group, and utilizes the focusing group in conjunction with the rear fixed group to achieve high-definition dual-band imaging with a large target surface, effectively improving the overall performance of the lens.

[0020] Please see Figure 1 , Figure 1 This is a structural diagram of the optical system of the wide temperature range, large target surface, high-definition dual-band lens provided by the present invention; wherein, the wide temperature range, large target surface, high-definition dual-band lens provided by the present invention includes a focusing group 10, a filter group 20 and a rear fixing group 30 arranged sequentially along the incident light direction; the filter group 20 is mounted on a wheel-type switching mechanism and is equipped with multiple filters 201 (B1) adapted to different imaging scenarios for optical filtering or polarization processing of incident light; The focusing group 10 is movably positioned along the optical axis to ensure that the wide-temperature-range, large-target-area, high-definition dual-band lens maintains image plane stability in a wide temperature range of -55 to 85℃ and in close-up working environments. The wheel-type switching mechanism is used to drive the filter 201 to rotate, allowing a single filter 201 to selectively engage with the optical axis and complete the switching of different imaging modes. The rear fixed group 30 cooperates with the focusing group 10 to achieve high-definition dual-band imaging under a wide temperature range and large target area.

[0021] In this embodiment of the invention, the optical elements in the focusing group 10 and the rear fixing group 30 are all spherical lenses, and both adopt non-cemented lens structures. Among them, the spherical lens processing technology is mature, the manufacturing cost is low, and the yield rate is high, which greatly reduces the production difficulty and mass production cost of the lens. In addition, the non-cemented structure can completely avoid the problems of delamination, stress deformation and image quality degradation caused by uneven thermal expansion and contraction of the cement layer in traditional cemented lenses under high and low temperature environments, thereby improving the optical stability and imaging consistency of the lens in a wide temperature range.

[0022] In this embodiment of the invention, the focusing group 10 includes a first biconvex lens 101 (A1), a first meniscus lens 102 (A2), a second biconvex lens 103 (A3), and a first biconcave lens 104 (A4) arranged sequentially along the incident direction of light. The air gap between the first biconvex lens 101 and the first meniscus lens 102 is 0.25-0.35 mm, the air gap between the first meniscus lens 102 and the second biconvex lens 103 is 0.6-0.7 mm, and the air gap between the second biconvex lens 103 and the first biconcave lens 104 is 0.6-0.7 mm.

[0023] Specifically, the first biconvex lens 101 is responsible for initially converging the incident light rays to complete the basic optical path focusing; the first meniscus lens 102 is used to correct the primary aberrations generated in the optical path and straighten the light propagation path; the second biconvex lens 103 further enhances the light-gathering effect, increases the light transmission and overall image brightness; and the first biconcave lens 104 specifically corrects residual optical aberrations such as dispersion and distortion, further optimizing the image quality.

[0024] Specifically, the four optical elements in the focusing group 10 define the air gap, which can not only precisely control the optical path and the angle of light propagation, effectively avoid optical interference between adjacent lenses and suppress stray light interference on imaging, but also optimize the stress distribution of the entire focusing group 10, so that the focusing group 10 has both excellent aberration correction capability and temperature deformation compensation capability, ensuring that the lens can maintain image plane stability in a wide temperature range of -55 to 85℃ and in close-up conditions.

[0025] In this embodiment of the invention, the rear fixing group 30 includes a second biconcave lens 301 (C1), a third biconvex lens 302 (C2), and a fourth biconvex lens 303 (C3) arranged sequentially along the incident direction of light; wherein the air gap between the second biconcave lens 301 and the third biconvex lens 302 is 0.45 to 0.55 mm, and the air gap between the third biconvex lens 302 and the fourth biconvex lens 303 is 9.5 to 10.5 mm.

[0026] Specifically, the second biconcave lens 301 mainly adjusts the divergence of the incident beam, effectively corrects residual chromatic aberration, distortion and other aberrations in the previous optical path, and balances the overall optical structure; the third biconvex lens 302 is responsible for converging the beam, further focusing the light, improving light transmission efficiency and regulating the shape of the optical path; the fourth biconvex lens 303 completes the final light focusing, ensuring that dual-band light can be accurately transmitted, and adapting to the usage requirements of large target imaging.

[0027] Furthermore, the air gap between the second biconcave lens 301 and the third biconvex lens 302 can precisely control the optical path difference, finely correct local optical deviations, and avoid light crosstalk between adjacent lenses; while the air gap between the third biconvex lens 302 and the fourth biconvex lens 303 can fully expand the beam, further optimize the field of view uniformity, and at the same time help compensate for small deformation errors in a wide temperature environment.

[0028] In this embodiment of the invention, the filter 201 is selected from one of visible light filters, near-infrared filters, narrowband filters and polarizing filters; the air gap between the first biconcave lens 104 and the filter 201 located on the optical axis is 40-50 mm, and the air gap between the filter 201 located on the optical axis and the second biconcave lens 301 is 5-7 mm.

[0029] Specifically, visible light filters and near-infrared filters can selectively transmit light in their respective wavelength bands, supporting wide-temperature-range, large-surface, high-definition dual-band lenses to switch between dual-band imaging; narrow-band filters can precisely select light in specific wavelength bands, effectively filtering out ambient stray light and improving the imaging signal-to-noise ratio; polarizing filters can reduce strong light reflection and glare interference, optimizing the imaging image under complex lighting conditions; the above-mentioned diverse filters 201 can meet the usage needs of different imaging modes and complex application scenarios.

[0030] Furthermore, an air gap is provided between the first biconcave lens 104 and the filter 201, which can not only fully expand the beam of the front-end optical path and prevent excessive beam convergence from causing optical distortion, but also reserve sufficient movement space for the wheel-type switching mechanism to ensure that the switching action of the filter 201 is stable and smooth; an air gap is provided between the filter 201 and the second biconcave lens 301 to precisely control the beam incident angle, smoothly connect the optical paths of the front and rear optical components, and reduce light energy loss and aberration superposition.

[0031] In this embodiment of the invention, preferably, the refractive index and Abbe number of the optical elements in the focusing group 10, the filter group 20, and the rear fixing group 30 satisfy the following conditions: 1.45<n1<1.55, 75<V1<85; 1.6<n2<1.7, 55<V2<65; 1.45<n3<1.55, 75<V3<85; 1.7<n4<1.8, 45<V4<55; 1.45<n5<1.55, 60<V5<70; 1.55<n6<1.65, 60<V6<70; 1.45<n7<1.55, 65<V7<75; 1.6<n8<1.7, 30<V8<40; Wherein, n1, n2, n3, n4, n5, n6, n7, and n8 are the refractive indices of the first biconvex lens 101, the first meniscus lens 102, the second biconvex lens 103, the first biconcave lens 104, the filter 201, the second biconcave lens 301, the third biconvex lens 302, and the fourth biconvex lens 303, respectively; and V1, V2, V3, V4, V5, V6, V7, and V8 are the Abbe numbers of the first biconvex lens 101, the first meniscus lens 102, the second biconvex lens 103, the first biconcave lens 104, the filter 201, the second biconcave lens 301, the third biconvex lens 302, and the fourth biconvex lens 303, respectively.

[0032] Specifically, the first biconvex lens 101 and the second biconvex lens 103 are made of materials with high Abbe number and medium refractive index, which can effectively converge light while suppressing the fundamental dispersion problem at the source; the first meniscus lens 102 is made of materials with medium refractive index and medium Abbe number, which can help correct spherical aberration and astigmatism in the optical path and regulate the propagation pattern of light; the first biconcave lens 104 is made of materials with high refractive index and low Abbe number, which, together with the two convex lenses on the front side, form a positive and negative lens combination to accurately cancel the residual chromatic aberration and distortion generated by the entire optical path; the filter 201, the second biconcave lens 301, the third biconvex lens 302 and the fourth biconvex lens 303 are matched with the refractive index and Abbe number of the corresponding range in sequence, which can not only ensure the stable performance of the core functions such as filtering and beam splitting, optical path transition and end beam focusing, but also avoid the introduction of additional optical deviations by the components themselves. At the same time, the gradient parameter matching can adapt to the dual-band light propagation characteristics and the large target surface imaging requirements, and improve the uniformity of the full field of view imaging.

[0033] The technical solution of the present invention will now be described in conjunction with specific embodiments.

[0034] Example 1: Please see Figure 1 This embodiment 1 provides a wide temperature range, large target surface, high-definition dual-band lens, including a focusing group 10, a filter group 20 and a rear fixing group 30 arranged sequentially along the incident light direction; the filter group 20 is mounted on a wheel-type switching mechanism and is equipped with multiple filters 201 adapted to different imaging scenarios for optical filtering or polarization processing of incident light. The focusing group 10 is movably positioned along the optical axis to ensure that the wide-temperature-range, large-target-area, high-definition dual-band lens maintains image plane stability in a wide temperature range of -55 to 85℃ and in close-up working environments. The wheel-type switching mechanism is used to drive the filter 201 to rotate, allowing a single filter 201 to selectively engage with the optical axis and complete the switching of different imaging modes. The rear fixed group 30 cooperates with the focusing group 10 to achieve high-definition dual-band imaging under a wide temperature range and large target area.

[0035] In this embodiment 1, the optical elements in the focusing group 10 and the rear fixing group 30 are all spherical mirrors, and all adopt non-cemented lens structures, and are all made of CDGM (Chengdu Guangming Optoelectronic Co., Ltd.) standard optical glass materials.

[0036] In this embodiment 1, the air gap between the center of the focusing group 10 and the center of the filter 201 located on the optical axis in the filter group 20 is 42.152 mm, and the air gap between the center of the filter 201 located on the optical axis in the filter group 20 and the rear fixing group 30 is 6 mm.

[0037] In this embodiment 1, the focusing group 10 includes a first biconvex lens 101, a first meniscus lens 102, a second biconvex lens 103, and a first biconcave lens 104 arranged sequentially along the light incident direction; the filter 201 is selected from one of a visible light filter, a near-infrared filter, a narrow band filter, and a polarizing filter; the rear fixing group 30 includes a second biconcave lens 301, a third biconvex lens 302, and a fourth biconvex lens 303 arranged sequentially along the light incident direction.

[0038] Specifically, the air gap between the first biconvex lens 101 and the first meniscus lens 102 is 0.295 mm, the air gap between the first meniscus lens 102 and the second biconvex lens 103 is 0.678 mm, and the air gap between the second biconvex lens 103 and the first biconcave lens 104 is 0.655 mm; the air gap between the first biconcave lens 104 and the filter 201 located on the optical axis is 42.152 mm, the air gap between the filter 201 located on the optical axis and the second biconcave lens 301 is 6 mm; the air gap between the second biconcave lens 301 and the third biconvex lens 302 is 0.45–0.498 mm, and the air gap between the third biconvex lens 302 and the fourth biconvex lens 303 is 10.14 mm.

[0039] In this embodiment 1, the visible light filter, near-infrared filter, narrowband filter, and polarizer in the filter assembly 20 are made of H-K9L material, HB720 material, HWB850 material, and H-K9L material, respectively. The thicknesses of the visible light filter, near-infrared filter, narrowband filter, and polarizer are 2.3 mm, 2.1 mm, 2.1 mm, and 2.3 mm, respectively.

[0040] In this embodiment 1, the focal length f1 of the first biconvex lens 101 is 69mm < f1 < 77mm; the focal length f2 of the first meniscus lens 102 is -86mm < f2 < -77mm; the focal length f3 of the second biconvex lens 103 is 38mm < f3 < 43mm; the focal length f4 of the first biconcave lens 104 is -58mm < f4 < -52mm; the focal length f6 of the second biconcave lens 301 is -19.7mm < f6 < -17.8mm; the focal length f7 of the third biconvex lens 302 is 39mm < f7 < 43.5mm; and the focal length f8 of the fourth biconvex lens 303 is 65mm < f8 < 72.2mm.

[0041] Specifically, the aforementioned positive focal length convex lens converges light and enhances light transmission capability step by step according to the focal length gradient, while negative focal length lenses of different specifications work together to systematically correct various aberrations such as spherical aberration, chromatic aberration, and distortion. At the same time, it assists the focusing structure in completing temperature change compensation and close-up focusing. The focal length parameters of the lens in the rear fixed group 30 can smoothly connect the front and rear optical paths and regulate the beam shape, ultimately achieving accurate imaging of dual-band light.

[0042] Please see Figure 2 , Figure 2 The image shows the optical-mechanical structure of the wide-temperature-range, large-area, high-definition dual-band lens provided in Example 1. The overall structure of the lens in Example 1 will be described in detail below: The wide temperature range, large target area, high-definition dual-band lens provided in this embodiment 1 is equipped with a wheel-type switching mechanism. This mechanism consists of a filter gear 410 and a filter wheel seat 411. The filter gear 410 is fixedly installed at the middle position of the lens tube 409 through the filter wheel seat 411. During operation, the filter gear 410 can drive the filter wheel seat 411 to rotate, and the filters 201 are batch-fixed on the filter wheel seat 411.

[0043] Specifically, the main structural components of the wide temperature range, large target surface, high-definition dual-band lens provided in this embodiment 1 include a focusing frame 408, a filter gear 410, and a rear frame 412. The focusing frame 408 is used to fix the first biconvex lens 101, the first meniscus lens 102, the second biconvex lens 103, and the first biconcave lens 104. The filter gear 10 is used to fix the filter group 20. The rear frame 412 is used to fix the second biconcave lens 301, the third biconvex lens 302, and the fourth biconvex lens 303. In the overall assembly layout, the focusing frame 408 is fixed to the front end of the lens tube 409 by the front objective lens retaining ring 401. The filter gear 410 is fixed to the middle end of the lens tube 409 by the filter wheel seat 411. The rear frame 412 is fixed to the rear end of the lens tube 409 by the rear retaining ring 417.

[0044] Specifically, in the front-end assembly structure, a first spacer 402 is provided between the front objective lens retaining ring 1 and the first biconvex lens 101; the first meniscus lens 102 and the second biconvex lens 103 are integrally assembled inside the objective lens frame 405 and locked and fixed by the first retaining ring 404, with a third spacer 406 provided between them; a second spacer 403 is provided between the first biconvex lens 101 and the objective lens frame 405; and a fourth spacer 407 is provided between the objective lens frame 405 and the first biconcave lens 104. In the rear-end assembly structure, a fifth spacer 413 is provided between the second biconcave lens 301 and the third biconvex lens 302, and this lens group is fixed inside the rear lens frame 412 by the second retaining ring 414; a sixth spacer 415 and a seventh spacer 416 are respectively assembled on both sides of the fourth biconvex lens 303, and the lens and its matching spacers are fixed inside the rear lens frame 412 by the third retaining ring 417.

[0045] Specifically, the physical parameters of each optical element in the wide temperature range large target surface high-definition near-infrared fixed-focus lens provided in Example 1 (taking visible light band imaging as an example) are shown in Table 1 below, where the unit of radius of curvature and thickness is mm.

[0046] Table 1

[0047] Specifically, the optical system parameters of the wide-temperature-range large-target-area high-definition near-infrared fixed-focus lens provided in Example 1 are as follows: The optical system parameters of the wide-temperature-range large-target-area high-definition dual-band lens are as follows: the working wavelength is 420nm~650nm, 700nm~900nm and 1064nm, the focal length is 142.48mm, the total optical length is 108mm, the field of view is 5.76°×5.76°, the aperture is 30mm, and the optical distortion is ≤0.87%; the working temperature range is -55~85℃, the near-field measurement distance is 10m; the compatible imaging target surface size is 4096×4096, the single pixel size is 3.5μm, and the lens diagonal image height is 22mm.

[0048] Specifically, when the wide-temperature-range, large-area, high-definition dual-band lens operates in an environment of -55℃, the focusing group 10 moves axially by 0.27mm towards the image plane; when the wide-temperature-range, large-area, high-definition dual-band lens operates in an environment of 85℃, the focusing group 10 moves axially by 0.28mm away from the image plane; and when the wide-temperature-range, large-area, high-definition dual-band lens observes a 10m close-up target, the focusing group 10 moves axially by 0.79mm away from the image plane.

[0049] Please see Figures 3 to 8 , Figure 3 , Figure 4 , Figure 5 The point plot, transfer function plot, and field curvature / distortion plot of the wide temperature range, large target area, high-definition dual-band lens provided in this embodiment 1 at room temperature in the visible light band; Figure 6 , Figure 7 , Figure 8 The diagram shows the dot plot, transfer function plot, and field curvature / distortion plot of the wide temperature range, large target area, high-definition dual-band lens provided in this embodiment 1 at room temperature in the near-infrared band.

[0050] Specifically, by Figure 3 and Figure 6 As can be seen from the corresponding dot plot, the light rays from each aperture band and each field of view, after passing through the wide-temperature-range, large-surface, high-definition dual-band lens of Example 1, focus onto the image plane in a relatively small spot; from Figure 4 and Figure 7 The corresponding transfer function graph shows that the wide-temperature-range, large-target-area, high-definition dual-band lens of Example 1 has a transfer function of >0.45 across the entire field of view at 142 lp / mm in the visible light band, and a transfer function of >0.3 across the entire field of view at 142 lp / mm in the near-infrared band; Figure 5 and Figure 8 The corresponding field curvature / distortion diagrams show that the system astigmatism of the wide-temperature-range, large-target-area, high-definition dual-band lens in Example 1 is small, with a maximum distortion of 0.87% in the visible light band and less than 0.91% in the near-infrared band. This indicates that the lens aberration has been effectively corrected, and the resolution is excellent, resulting in high-definition imaging.

[0051] Please see Figures 9 to 12 , Figure 9 , Figure 10 The point plot and transfer function diagram of the wide temperature range, large target area, high-definition dual-band lens provided in this embodiment 1 in the visible light band and at a temperature of -55℃. Figure 11 , Figure 12 The diagram shows the dot plot and transfer function of the wide-temperature-range, large-surface, high-definition dual-band lens provided in Embodiment 1 in the near-infrared band and at a temperature of -55℃.

[0052] Specifically, by Figure 9 and Figure 11 As can be seen from the corresponding dot plot, the light rays from each aperture band and each field of view, after being focused onto the image plane by the wide-temperature-range, large-surface, high-definition dual-band lens provided in Example 1, result in a smaller spot size. Figure 10 and Figure 12 The corresponding transfer function graph shows that the wide-temperature-range, large-surface-area, high-definition dual-band lens provided in Example 1 has a transfer function of >0.4 across the entire field of view at 142 lp / mm in the visible light band and >0.27 across the entire field of view at 142 lp / mm in the near-infrared band. This indicates that the lens performs well in a temperature environment of -55℃.

[0053] Please see Figures 13 to 16 , Figure 13 , Figure 14The point graph and transfer function graph of the wide temperature range large target area high-definition dual-band lens provided in this embodiment 1 in the visible light band and at a temperature of 85°C are shown. Figure 15 , Figure 16 The diagram shows the dot plot and transfer function of the wide-temperature-range, large-surface, high-definition dual-band lens provided in Embodiment 1 in the near-infrared band at a temperature of 85°C.

[0054] Depend on Figure 13 and Figure 15 As can be seen from the corresponding dot plot, the light rays from each aperture band and each field of view, after being focused onto the image plane by the wide-temperature-range, large-surface, high-definition dual-band lens provided in Example 1, result in a smaller spot size. Figure 14 and Figure 16 The corresponding transfer function graph shows that the lens's transfer function in the visible light band is >0.41 across the entire field of view at 142 lp / mm, and its transfer function in the near-infrared band is >0.28 across the entire field of view at 142 lp / mm. This indicates that the wide-temperature-range, large-area, high-definition dual-band lens provided in Example 1 performs excellently at 85℃.

[0055] Please see Figures 17 to 20 , Figure 17 , Figure 18 The point plot and transfer function diagram of the wide temperature range, large target surface, high-definition dual-band lens provided in this embodiment 1 when observing a close-up scene of 10m in the visible light band; Figure 19 , Figure 20 The diagram shows the point plot and transfer function of the wide-temperature-range, large-target-area, high-definition dual-band lens provided in Example 1 when observing a close-up scene at 10m in the near-infrared band.

[0056] Specifically, by Figure 17 and Figure 19 As can be seen from the corresponding dot plot, the light rays from each aperture band and each field of view, after being focused onto the image plane by the wide-temperature-range, large-surface, high-definition dual-band lens provided in Example 1, result in a smaller spot size. Figure 18 and Figure 20 The corresponding transfer function graph shows that the wide temperature range, large target surface, high-definition dual-band lens provided in Example 1 has a transfer function of >0.4 in the visible light band at 142 lp / mm and a transfer function of >0.26 in the near-infrared band at 142 lp / mm, indicating that the lens has excellent performance when the object distance range is 10 to ∞m.

[0057] Compared with the prior art, the present invention has the following advantages: First, the wide-temperature-range, large-target-area, high-definition dual-band lens provided in this embodiment of the invention has excellent high-definition imaging performance. The lens has a diagonal image height of 22mm and can be equipped with a large-target-area camera with a resolution of 4096×4096. The camera pixel size is 3.5μm, which can meet the high-definition imaging requirements of the lens. Second, the wide temperature range large target surface high-definition dual-band lens provided in the embodiments of the present invention has excellent imaging performance in a wide temperature range environment of -55 to 85℃ and can maintain good optical performance when working in extreme environments. Third, all optical components of the wide temperature range, large target surface, high-definition dual-band lens provided in this embodiment of the invention are free of adhesive parts, which eliminates the phenomenon of glue separation from the source and has strong practicality. Fourth, the wide temperature range, large target area, high-definition dual-band lens provided in this embodiment of the invention is a dual-band fixed-focus design. Relying on the switchable filter 201, it can achieve dual-band imaging of visible light and near-infrared light, and also supports flexible switching of multiple imaging modes, greatly improving scene adaptability.

[0058] It should be noted that all the above embodiments belong to the same inventive concept, and the descriptions of each embodiment have different focuses. Where the description in a particular embodiment is not detailed, please refer to the description in other embodiments.

[0059] The above embodiments merely illustrate implementation methods of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A wide-temperature-range, large-area, high-definition dual-band lens, characterized in that, It includes a focusing group, a filter group and a rear fixing group arranged sequentially along the incident direction of light; the filter group is mounted on a wheel-type switching mechanism and is equipped with multiple filters adapted to different imaging scenarios for optical filtering or polarization processing of incident light. The focusing group is movably arranged along the optical axis to ensure that the wide-temperature-range, large-target-area, high-definition dual-band lens maintains image plane stability in a wide temperature range of -55 to 85°C and in close-up working environments. The wheel-type switching mechanism is used to drive the filter to rotate, allowing a single filter to selectively engage with the optical axis and complete the switching of different imaging modes. The rear fixing group cooperates with the focusing group to achieve high-definition dual-band imaging under a wide temperature range and large target area.

2. The wide temperature range, large target area, high-definition dual-band lens according to claim 1, characterized in that, The optical elements in both the focusing group and the rear fixing group are spherical mirrors, and both adopt a non-cemented lens structure.

3. The wide temperature range, large target area, high-definition dual-band lens according to claim 2, characterized in that, The focusing group includes a first biconvex lens, a first meniscus lens, a second biconvex lens, and a first biconcave lens arranged sequentially along the incident direction of light. The air gap between the first biconvex lens and the first meniscus lens is 0.25–0.35 mm, the air gap between the first meniscus lens and the second biconvex lens is 0.6–0.7 mm, and the air gap between the second biconvex lens and the first biconcave lens is 0.6–0.7 mm.

4. The wide temperature range, large target area, high-definition dual-band lens according to claim 3, characterized in that, The rear fixing group includes a second biconcave lens, a third biconvex lens, and a fourth biconvex lens arranged sequentially along the incident direction of light. The air gap between the second biconcave lens and the third biconvex lens is 0.45–0.55 mm, and the air gap between the third biconvex lens and the fourth biconvex lens is 9.5–10.5 mm.

5. The wide temperature range, large target area, high-definition dual-band lens according to claim 4, characterized in that, The filter is selected from one of visible light filters, near-infrared filters, narrowband filters, and polarizing filters; the air gap between the first biconcave lens and the filter located on the optical axis is 40-50 mm, and the air gap between the filter located on the optical axis and the second biconcave lens is 5-7 mm.

6. The wide temperature range, large target area, high-definition dual-band lens according to claim 5, characterized in that, The refractive index and Abbe number of the optical elements in the focusing group, the filter group, and the rear fixing group satisfy the following conditions: 1.45<n1<1.55, 75<V1<85; 1.6<n2<1.7, 55<V2<65; 1.45<n3<1.55, 75<V3<85; 1.7<n4<1.8, 45<V4<55; 1.45<n5<1.55, 60<V5<70; 1.55<n6<1.65, 60<V6<70; 1.45<n7<1.55, 65<V7<75; 1.6<n8<1.7, 30<V8<40; Wherein, n1, n2, n3, n4, n5, n6, n7, and n8 are the refractive indices of the first biconvex lens, the first meniscus lens, the second biconvex lens, the first biconcave lens, the filter, the second biconcave lens, the third biconvex lens, and the fourth biconvex lens, respectively; and V1, V2, V3, V4, V5, V6, V7, and V8 are the Abbe numbers of the first biconvex lens, the first meniscus lens, the second biconvex lens, the first biconcave lens, the filter, the second biconcave lens, the third biconvex lens, and the fourth biconvex lens, respectively.

7. The wide temperature range, large target area, high-definition dual-band lens according to claim 6, characterized in that, The focal length f1 of the first biconvex lens is 69mm < f1 < 77mm; the focal length f2 of the first meniscus lens is -86mm < f2 < -77mm; the focal length f3 of the second biconvex lens is 38mm < f3 < 43mm; the focal length f4 of the first biconcave lens is -58mm < f4 < -52mm; the focal length f6 of the second biconcave lens is -19.7mm < f6 < -17.8mm; the focal length f7 of the third biconvex lens is 39mm < f7 < 43.5mm; and the focal length f8 of the fourth biconvex lens is 65mm < f8 < 72.2mm.

8. The wide temperature range, large target area, high-definition dual-band lens according to claim 1, characterized in that, The wheel-type switching mechanism includes a filter gear and a filter wheel seat. The filter gear is fixed to the middle end of the lens tube of the wide temperature range large target area high-definition dual-band lens through the filter wheel seat. The filter gear drives the filter wheel seat to rotate, and multiple filters are fixedly installed on the filter wheel seat.

9. The wide temperature range, large target area, high-definition dual-band lens according to any one of claims 1 to 8, characterized in that, The optical system parameters of the wide-temperature-range, large-target-area, high-definition dual-band lens are as follows: operating wavelengths of 420nm~650nm, 700nm~900nm and 1064nm, focal length of 142.48mm, total optical length of 108mm, field of view of 5.76°×5.76°, aperture of 30mm, and optical distortion ≤0.87%; operating temperature range of -55~85℃, near-field measurement distance of 10m; compatible imaging target surface size of 4096×4096, single pixel size of 3.5μm, and lens diagonal image height of 22mm.

10. The wide temperature range, large target area, high-definition dual-band lens according to claim 9, characterized in that, When the wide-temperature-range, large-area, high-definition dual-band lens operates in an environment of -55℃, the focusing group moves axially 0.27mm closer to the image plane; when the wide-temperature-range, large-area, high-definition dual-band lens operates in an environment of 85℃, the focusing group moves axially 0.28mm further away from the image plane; when the wide-temperature-range, large-area, high-definition dual-band lens observes a 10m close-up target, the focusing group moves axially 0.79mm further away from the image plane.

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