Wide-temperature-range large-target high-definition near-infrared lens

Abstract

This invention provides a wide-temperature-range, large-area high-definition near-infrared lens. First, by setting a plane mirror in the optical path to achieve optical path deflection, it effectively compresses the axial structural size of the lens, solving the problems of large size and poor integration of traditional large-area near-infrared lenses. Second, through a two-stage graded aberration correction architecture with the front and rear fixed groups working in coordination, it fundamentally avoids the common problem of image quality degradation at the edge of large targets, perfectly adapting to large-area, high-resolution detectors. Finally, by setting a focusing group that can move independently along the optical axis, it can simultaneously compensate for changes in the refractive index of optical elements under high and low temperature environments, image plane drift caused by thermal expansion and contraction of structural components, and focusing deviation during close-up shooting, completely solving the industry problem of blurred imaging and drastic degradation of close-up image quality in traditional fixed-focus lenses under extreme temperatures.

Description

Technical Field

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

[0002] Near-infrared imaging boasts advantages such as strong penetration, good anti-interference capabilities, and all-weather operation, and is now widely used in industrial inspection, security monitoring, aerospace, machine vision, and scientific research. The fixed-focus lens is the core optical component of a near-infrared imaging system, and its performance directly affects the imaging effect and environmental adaptability of the entire system. Currently, imaging detectors are increasingly developing towards larger target areas and higher resolutions, which also places higher demands on the matching near-infrared fixed-focus lenses, requiring them to meet stringent specifications such as large target area adaptation, stable operation over a wide temperature range, and high imaging quality.

[0003] Currently, conventional near-infrared 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, insufficient adaptability to large target surfaces. Most existing near-infrared fixed-focus lenses are designed only for small-sized target surface detectors. When adapted to large target surface detectors, they cannot achieve uniform light convergence across the entire field of view, easily leading to problems such as a sharp increase in edge field-of-view aberrations, insufficient relative illumination, and excessive distortion. This makes it difficult to cover the complete imaging area of ​​a large target surface, resulting in blurred edges and uneven brightness in the image. This prevents the full utilization of the large field of view and high resolution advantages of large target surface detectors, limiting the application of near-infrared imaging systems in high-precision detection and large-area monitoring scenarios. Second, poor stability over a wide temperature range. The refractive index of the lens material, the lens spacing, and the mechanical structure of an optical lens will change with the ambient temperature. Conventional near-infrared lenses have a narrow temperature range corresponding to their thermal differential design. When in extreme high and low temperature complex environments, the lens is prone to thermal defocusing and image plane drift, resulting in a significant decrease in image clarity. This makes it difficult to meet the long-term reliable working requirements of extreme temperature environments such as the field, vehicle, and airborne.

[0004] Therefore, there is an urgent need for a wide-temperature-range, large-area, high-definition near-infrared 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 near-infrared lens, so as to achieve the performance requirements of being adaptable to large-target-area detectors, adapting to a wide operating temperature range, and having 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 near-infrared lens, comprising a front fixed group, a plane mirror, a rear fixed group, and a focusing group arranged sequentially along the light incident direction; The front fixed group is used to receive incident light, perform initial focusing of the incident light, and correct primary aberrations and chromatic aberrations; the plane mirror is used to deflect the light path to compress the size of the lens structure; the rear fixed group is used to further correct residual aberrations of the system to adapt to high-definition imaging of large target surfaces; the focusing group is movable along the optical axis to compensate for high and low temperature drift and close-up focusing deviation, so as to achieve stable imaging of the image plane in a wide temperature range.

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

[0008] Preferably, the front fixing group includes a filter, a first biconvex lens, a first biconcave lens and a first plano-convex lens arranged sequentially along the light incident direction; The air gap between the filter and the first biconvex lens is 0.9–1.1 mm, the air gap between the first biconvex lens and the first biconcave lens is 1.45–1.5 mm, the air gap between the first biconcave lens and the first plano-convex lens is 0.7–0.75 mm, and the air gap between the first plano-convex lens and the center of the plane mirror is 28–30 mm.

[0009] Preferably, the rear fixing group includes a second biconvex lens, a first meniscus lens, and a second meniscus lens arranged sequentially along the incident direction of light. The air gap between the center of the plane mirror and the second biconvex lens is 19–21 mm; the air gap between the second biconvex lens and the first meniscus lens is 0.7–0.8 mm; and the air gap between the first meniscus lens and the second meniscus lens is 4.5–5 mm.

[0010] Preferably, the focusing group includes a third biconvex lens and a second biconcave lens arranged sequentially along the incident direction of light; wherein the air gap between the second meniscus lens and the third biconvex lens is 4-5 mm, and the air gap between the third biconvex lens and the second biconcave lens is 0.7-0.75 mm.

[0011] Preferably, the refractive index and Abbe number of the optical elements in the front fixed group, the plane mirror, the rear fixed group, and the focusing group satisfy the following conditions: 1.5<n1<1.55, 60<V1<70; 1.55<n2<1.6, 60<V2<70; 1.65<n3<1.7, 35<V3<45; 1.55<n4<1.6, 70<V4<80; 1.5<n5<1.55, 60<V5<70; 1.6<n6<1.65, 50<V6<60; 1.65<n7<1.7, 50<V7<60; 1.55<n8<1.6, 55<V8<65; 1.75<n9<1.8, 45<V9<55; 1.55<n 10 <1.6, 35<V 10 <45; Among them, n1, n2, n3, n4, n5, n6, n7, n8, n9 and n 10 The refractive indices of the following lenses, in order: filter, first biconvex lens, first biconcave lens, first plano-convex lens, plane mirror, second biconvex lens, first meniscus lens, second meniscus lens, third biconvex lens, and second biconcave lens; V1, V2, V3, V4, V5, V6, V7, V8, V9, and V... 10 The Abbe numbers of the following lenses are, in order: filter, first biconvex lens, first biconcave lens, first plano-convex lens, plane mirror, second biconvex lens, first meniscus lens, second meniscus lens, third biconvex lens, and second biconcave lens.

[0012] Preferably, the focal length f2 of the first biconvex lens is: 63mm < f2 < 70mm; the focal length f3 of the first biconcave lens is -71mm < f3 < -63mm; the focal length f4 of the first plano-convex lens is 101mm < f4 < 113mm; the focal length f6 of the second biconvex lens is 45mm < f6 < 51mm; the focal length f7 of the first meniscus lens is -68mm < f7 < -60mm; the focal length f8 of the second meniscus lens is -54mm < f8 < -48mm; the focal length f9 of the third biconvex lens is 32mm < f9 < 37mm; and the focal length f2 of the second biconcave lens is... 10 -47mm < f 10 <-41mm.

[0013] Preferably, the optical elements in the front fixing group, the rear fixing group, and the focusing group are all made of CDGM standard optical glass material.

[0014] Preferably, the optical system parameters of the wide temperature range, large target surface, high-definition near-infrared fixed-focus lens are as follows: working wavelength range of 600nm~900nm, focal length of 107.54mm, total optical length of 178mm, field of view of 9.58°×9.58°, exit pupil distance of 59mm, exit pupil diameter of 22mm, optical distortion ≤0.19%; working temperature range of -55~85℃, near-field measurement distance of 10m; compatible imaging target surface size of 4096×4096, single pixel size of 4.4μm, and lens diagonal image height of 27.2mm.

[0015] Preferably, when the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens operates in an environment of -55℃, the focusing group moves axially 4.44mm closer to the image plane; when the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens operates in an environment of 85℃, the focusing group moves axially 3.68mm further away from the image plane; when the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens observes a 10m close-up target, the focusing group moves axially 2.84mm 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-area, high-definition near-infrared lens. Firstly, by setting a plane mirror in the optical path to achieve optical path deflection, it effectively compresses the axial structural size of the lens, solving the problems of large size and poor integration of traditional large-area near-infrared lenses. Secondly, through a two-stage graded aberration correction architecture with the front and rear fixed groups working in coordination, it fundamentally avoids the common problem of image quality degradation at the edge of large targets, perfectly adapting to large-area, high-resolution detectors. Finally, by setting a focusing group that can move independently along the optical axis, it can simultaneously compensate for changes in the refractive index of optical elements under high and low temperature environments, image plane drift caused by thermal expansion and contraction of structural components, and focusing deviation during close-up shooting, completely solving the industry problem of blurred imaging and drastic degradation of close-up imaging quality in traditional fixed-focus lenses under extreme temperatures. Attached Figure Description

[0017] Figure 1 The optical system structure diagram of the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided by the present invention; Figure 2 This is an optical-mechanical structure diagram of the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in Embodiment 1. Figure 3 A room temperature dot plot of the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in Embodiment 1; Figure 4 The room temperature transfer function graph of the wide temperature range large target area high-definition near-infrared fixed-focus lens provided in Embodiment 1; Figure 5 Field curvature / distortion diagram of the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in this embodiment 1; Figure 6 A dot plot at -55°C for the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in Embodiment 1 of this invention. Figure 7 The transfer function at -55℃ for the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in Example 1 of this embodiment; Figure 8 This is a dot plot of the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in Example 1 of this invention at 85°. Figure 9The 85°C transfer function graph of the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in Embodiment 1; Figure 10 A series of images showing close-up observations at 10m using the wide-temperature-range, large-target-area, high-definition near-infrared fixed-focus lens provided in Example 1 of this embodiment; Figure 11 The transfer function graph of the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in this embodiment 1 at a close range of 10m. In the attached diagram: 10—Front fixed group; 101—Filter; 102—First biconvex lens; 103—First biconcave lens; 104—First plano-convex lens; 20—Plane mirror; 30—Rear fixed group; 301—Second biconvex lens; 302—First meniscus lens; 303—Second meniscus lens; 40—Focusing group; 401—Third biconvex lens; 402—Second biconcave lens; 501—Front pressure ring; 502—Front washer; 503—First spacer; 504—Second spacer; 505—Mirror mount; 506—Mirror frame; 507—Front mirror frame; 508—Mirror frame pressure plate; 509—Rear fixing pressure ring; 510—Third spacer; 511—Fourth spacer; 512—Rear fixing frame; 513—Fifth spacer; 514—Focusing shim; 515—Focusing pressure ring; 516—Focusing lens frame; 517—Rear lens tube. 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] The purpose of this invention is to address the shortcomings of existing technologies by providing a wide-temperature-range, large-target-area, high-definition near-infrared lens. This lens is adaptable to large-target-area detectors, meets the requirements of a wide operating temperature range, and offers excellent image quality across the entire field of view and temperature range.

[0020] Please see Figure 1 , Figure 1 The optical system structure diagram of the wide temperature range large target surface high-definition near-infrared fixed-focus lens provided by the present invention is shown below. The wide temperature range large target surface high-definition near-infrared fixed-focus lens provided by the present invention includes a front fixed group 10, a plane mirror 20, a rear fixed group 30 and a focusing group 40 arranged sequentially along the light incident direction. The front fixed group 10 is used to receive incident light, perform preliminary focusing of the incident light, and correct primary aberrations and chromatic aberrations; the plane mirror 20 is used to deflect the light path to compress the lens structure size; the rear fixed group 30 is used to further correct residual aberrations of the system to adapt to high-definition imaging of large target surfaces; the focusing group 40 is movable along the optical axis to compensate for high and low temperature drift and close-up focusing deviation, so as to achieve stable imaging of the image plane in a wide temperature range.

[0021] In this embodiment of the invention, the optical elements in the front fixing group 10, the rear fixing group 30, and the focusing group 40 are all spherical lenses, and all 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 front fixing group 10 includes a filter 101 (A1), a first biconvex lens 102 (A2), a first biconcave lens 103 (A3), and a first plano-convex lens 104 (A4) arranged sequentially along the light incident direction. The air gap between the filter 101 and the first biconvex lens 102 is 0.9-1.1 mm, the air gap between the first biconvex lens 102 and the first biconcave lens 103 is 1.45-1.5 mm, the air gap between the first biconcave lens 103 and the first plano-convex lens 104 is 0.7-0.75 mm, and the air gap between the first plano-convex lens 104 and the center of the plane mirror 20 is 28-30 mm.

[0023] Specifically, the filter 101 is used to accurately filter stray light outside the working band of the wide-temperature-range, large-target-area, high-definition near-infrared fixed-focus lens, thereby improving the imaging signal-to-noise ratio and contrast. The first biconvex lens 102 serves as the main converging lens, completing the initial convergence of incident light and correcting paraxial primary spherical aberration. The first biconcave lens 103 and the first biconvex lens 102 form an equivalent achromatic combination, accurately correcting the system's axial chromatic aberration and primary coma. The first plano-convex lens 104 further collimates and converges the light and adjusts the exit angle, so that the light enters the plane mirror 20 at the optimal angle, avoiding the introduction of additional aberrations in the reflected light path.

[0024] Specifically, by precisely controlling the air gap between the filter 101 and the first biconvex lens 102, ghost image interference formed by reflected light from the surface of the filter 101 can be effectively suppressed; controlling the air gap between the first biconvex lens 102 and the first biconcave lens 103 can achieve efficient achromatic aberration in a non-cemented state, while avoiding the risk of high and low temperature failure of cemented lenses; controlling the air gap between the first biconcave lens 103 and the first plano-convex lens 104 can optimize the light divergence angle to assist in correcting off-axis aberrations; controlling the optical path distance between the first plano-convex lens 104 and the center of the plane mirror 20 can ensure the symmetry of the reflected light path and the axial dimension compression effect, while reducing stray light reflection.

[0025] In this embodiment of the invention, the plane mirror 20 bends the horizontal light rays emitted from the front fixed group 10 by 90° to form an L-shaped folded optical path, which can compress the total axial length of the lens by more than 40%, fundamentally solving the problem that the axial size of traditional large-area near-infrared fixed-focus lenses is too large and difficult to integrate into compact devices; at the same time, the plane mirror 20 only changes the direction of light propagation without introducing any additional aberrations, and can completely preserve the primary aberration state that has been corrected by the front fixed group 10, laying the foundation for subsequent large-area high-definition aberration correction.

[0026] In this embodiment of the invention, the rear fixing group 30 includes a second biconvex lens 301 (C1), a first meniscus lens 302 (C2), and a second meniscus lens 303 (C3) arranged sequentially along the incident direction of light; wherein, the air gap between the center of the plane mirror 20 and the second biconvex lens 301 is 19-21 mm; the air gap between the second biconvex lens 301 and the first meniscus lens 302 is 0.7-0.8 mm, and the air gap between the first meniscus lens 302 and the second meniscus lens 303 is 4.5-5 mm.

[0027] Specifically, the second biconvex lens 301 receives the light rays after the plane mirror 20 is deflected and converges them a second time, focusing on correcting the residual spherical aberration and axial chromatic aberration that were not completely eliminated by the previous fixed group 10; the first meniscus lens 302 works closely with the second biconvex lens 301 to mainly correct the primary astigmatism and coma of the system and improve the imaging clarity of the off-axis field of view; the second meniscus lens 303, as a flat field correction lens, accurately corrects the field curvature of the large field of view through its special meniscus shape, fundamentally solving the imaging blur problem caused by the curvature of the image plane at the edge of the large target detector, and ensuring uniform image quality throughout the entire field of view.

[0028] Specifically, by precisely controlling the air gap between the center of the plane mirror 20 and the second biconvex lens 301, the reflected light can be fully diffused to a suitable beam aperture; by controlling the narrow air gap between the second biconvex lens 301 and the first meniscus lens 302, the angle at which light is incident on the meniscus lens can be precisely controlled, maximizing the effect of their synergistic correction; by controlling the air gap between the first meniscus lens 302 and the second meniscus lens 303, the field curvature and astigmatism correction capabilities of the large field of view can be significantly improved, ensuring that the imaging quality of the edge field of view and the center field of view of the large target surface is consistent.

[0029] In this embodiment of the invention, the focusing group 40 includes a third biconvex lens 401 (D1) and a second biconcave lens 402 (D2) arranged sequentially along the incident direction of light; wherein, the air gap between the second meniscus lens 303 and the third biconvex lens 401 is 4-5 mm, and the air gap between the third biconvex lens 401 and the second biconcave lens 402 is 0.7-0.75 mm.

[0030] Specifically, the third biconvex lens 401 is responsible for converging the light corrected by the post-fixed group 30 and compensating for spherical aberration fluctuations generated during focusing. The second biconcave lens 402 works with it to form an achromatic focusing combination, ensuring that chromatic aberration will not drift significantly during focusing and guaranteeing consistent imaging colors at different object distances and temperatures.

[0031] Specifically, by precisely controlling the air gap between the second meniscus lens 303 and the third biconvex lens 401, sufficient axial movement travel can be provided for the focusing group 40, which can fully cover the entire compensation range required for high and low temperature image plane drift and close-up focusing. At the same time, the incident angle of light is optimized to reduce the amount of off-axis aberration change during focusing. Controlling the narrow air gap between the third biconvex lens 401 and the second biconcave lens 402 can achieve efficient achromatic aberration effect in the non-cemented state, ensuring uniform and stable imaging quality across the entire field of view before and after focusing.

[0032] In this embodiment of the invention, the refractive index and Abbe number of the optical elements in the front fixing group 10, the plane mirror 20, the rear fixing group 30, and the focusing group 40 satisfy the following conditions: 1.5<n1<1.55, 60<V1<70; 1.55<n2<1.6, 60<V2<70; 1.65<n3<1.7, 35<V3<45; 1.55<n4<1.6, 70<V4<80; 1.5<n5<1.55, 60<V5<70; 1.6<n6<1.65, 50<V6<60; 1.65<n7<1.7, 50<V7<60; 1.55<n8<1.6, 55<V8<65; 1.75<n9<1.8, 45<V9<55; 1.55<n 10 <1.6, 35<V 10 <45; Among them, n1, n2, n3, n4, n5, n6, n7, n8, n9 and n 10 The refractive indices of the following lenses are, in order: filter 101, first biconvex lens 102, first biconcave lens 103, first plano-convex lens 104, plane mirror 20, second biconvex lens 301, first meniscus lens 302, second meniscus lens 303, third biconvex lens 401, and second biconcave lens 402; and V1, V2, V3, V4, V5, V6, V7, V8, V9, and V... 10 The Abbe numbers of the following components are, in order: filter 101, first biconvex lens 102, first biconcave lens 103, first plano-convex lens 104, plane mirror 20, second biconvex lens 301, first meniscus lens 302, second meniscus lens 303, third biconvex lens 401, and second biconcave lens 402.

[0033] Specifically, this invention precisely limits and grades the refractive index and Abbe number of all 10 optical elements, controlling the refractive index of each element within five gradient ranges from 1.5 to 1.8. This ensures that the light refraction capability of different functional lenses is precisely matched with their optical roles, guaranteeing sufficient convergence and divergence capabilities to optimize the optical path structure, while avoiding increased reflection loss and increased processing difficulty caused by high refractive index.

[0034] Specifically, the present invention employs a combination of low-dispersion and high-dispersion glass in the front fixed group 10 to form an efficient non-cemented achromatic combination; in the focusing group 40, medium-dispersion and high-dispersion glass are precisely matched to ensure that the system chromatic aberration remains stable during the axial movement of the focusing group 40 to compensate for high and low temperature image plane drift and close-up focusing deviation, thus completely avoiding color shift in imaging before and after focusing; in the rear fixed group 30, medium-dispersion glass is used to effectively correct residual spherical aberration, astigmatism, and field curvature without introducing additional chromatic aberration, ensuring uniform and consistent imaging across the entire field of view of the large target surface; in addition, the plane mirror 20 uses a low-dispersion glass substrate with a low coefficient of thermal expansion and good temperature stability, further enhancing the optical performance stability of the lens over a wide temperature range.

[0035] The technical solution of the present invention will now be described in conjunction with specific embodiments.

[0036] Example 1: Please see Figure 1 This embodiment 1 provides a wide temperature range, large target surface, high-definition near-infrared lens, including a front fixed group 10, a plane mirror 20, a rear fixed group 30 and a focusing group 40 arranged sequentially along the light incident direction; The front fixed group 10 is used to receive incident light, perform preliminary focusing of the incident light, and correct primary aberrations and chromatic aberrations; the plane mirror 20 is used to deflect the light path to compress the lens structure size; the rear fixed group 30 is used to further correct residual aberrations of the system to adapt to high-definition imaging of large target surfaces; the focusing group 40 is movable along the optical axis to compensate for high and low temperature drift and close-up focusing deviation, so as to maintain the stability of the image plane throughout the entire process under high and low temperature and close-up environments.

[0037] In Example 1, all optical elements in the front fixing group 10, the rear fixing group 30, and the focusing group 40 are spherical non-cemented lenses, and all are made of CDGM (Chengdu Guangming Optoelectronic Co., Ltd.) standard optical glass material.

[0038] In Example 1, the air gap between the center of the front fixed group 10 and the center of the plane mirror 20 is 28.998 mm, the air gap between the center of the plane mirror 20 and the rear fixed group 30 is 20.012 mm, and the air gap between the rear fixed group 30 and the focusing group 40 is 4.58 mm.

[0039] In Embodiment 1, the front fixing group 10 includes a filter 101, a first biconvex lens 102, a first biconcave lens 103, and a first plano-convex lens 104 arranged sequentially along the light incident direction; the rear fixing group 30 includes a second biconvex lens 301, a first meniscus lens 302, and a second meniscus lens 303 arranged sequentially along the light incident direction; and the focusing group 40 includes a third biconvex lens 401 and a second biconcave lens 402 arranged sequentially along the light incident direction.

[0040] Specifically, the air gap between the filter 101 and the first biconvex lens 102 is 1 mm; the air gap between the first biconvex lens 102 and the first biconcave lens 103 is 1.497 mm; the air gap between the first biconcave lens 103 and the first plano-convex lens 104 is 0.704 mm; the air gap between the first plano-convex lens 104 and the center of the plane mirror 20 is 28.998 mm; the air gap between the center of the plane mirror 20 and the second biconvex lens 301 is 20.012 mm; the air gap between the second biconvex lens 301 and the first meniscus lens 302 is 0.774 mm; the air gap between the first meniscus lens 302 and the second meniscus lens 303 is 4.955 mm; the air gap between the second meniscus lens 303 and the third biconvex lens 401 is 4.58 mm; and the air gap between the third biconvex lens 401 and the second biconcave lens 402 is 0.709 mm.

[0041] In Example 1, the refractive indices and Abbe numbers of the optical elements in the front fixing group 10, the plane mirror 20, the rear fixing group 30, and the focusing group 40 satisfy the following conditions: 1.5<n1<1.55, 60<V1<70; 1.55<n2<1.6, 60<V2<70; 1.65<n3<1.7, 35<V3<45; 1.55<n4<1.6, 70<V4<80; 1.5<n5<1.55, 60<V5<70; 1.6<n6<1.65, 50<V6<60; 1.65<n7<1.7, 50<V7<60; 1.55<n8<1.6, 55<V8<65; 1.75<n9<1.8, 45<V9<55; 1.55<n 10 <1.6, 35<V 10 <45; Among them, n1, n2, n3, n4, n5, n6, n7, n8, n9 and n 10 The refractive indices of the following lenses are, in order: filter 101, first biconvex lens 102, first biconcave lens 103, first plano-convex lens 104, plane mirror 20, second biconvex lens 301, first meniscus lens 302, second meniscus lens 303, third biconvex lens 401, and second biconcave lens 402; and V1, V2, V3, V4, V5, V6, V7, V8, V9, and V... 10 The Abbe numbers of the following components are, in order: filter 101, first biconvex lens 102, first biconcave lens 103, first plano-convex lens 104, plane mirror 20, second biconvex lens 301, first meniscus lens 302, second meniscus lens 303, third biconvex lens 401, and second biconcave lens 402.

[0042] In Embodiment 1, the focal length f2 of the first biconvex lens 102 is: 63mm < f2 < 70mm; the focal length f3 of the first biconcave lens 103 is -71mm < f3 < -63mm; the focal length f4 of the first plano-convex lens 104 is 101mm < f4 < 113mm; the focal length f6 of the second biconvex lens 301 is 45mm < f6 < 51mm; the focal length f7 of the first meniscus lens 302 is -68mm < f7 < -60mm; the focal length f8 of the second meniscus lens 303 is -54mm < f8 < -48mm; the focal length f9 of the third biconvex lens 401 is 32mm < f9 < 37mm; the focal length f2 of the second biconcave lens 402 is... 10 -47mm < f 10 <-41mm.

[0043] Please see Figure 2 , Figure 2 The optical-mechanical structure diagram of the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in Example 1 is shown below; the specific design of the lens structure in Example 1 is as follows: The wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens provided in Embodiment 1 adopts an L-shaped folded optical path layout. It mainly consists of four parts: a front fixed assembly, a plane mirror assembly, a rear fixed assembly, and a focusing assembly. All components are connected into a whole through a mirror mount 505 and a rear lens tube 517. The front fixed assembly includes a front lens frame 507 and a filter 101, a first biconvex lens 102, a first biconcave lens 103, and a first plano-convex lens 104 installed therein. The plane mirror assembly includes a mirror mount 505, a mirror frame 506, and a mirror frame pressure plate 508 for fixing the plane mirror 20. The rear fixed assembly includes a rear fixed frame 512 and a second biconvex lens 301, a first meniscus lens 302, and a second meniscus lens 303 installed therein. The focusing assembly includes a focusing lens frame 516 and a third biconvex lens 401 and a second biconcave lens 402 installed therein.

[0044] The specific assembly and fixing methods of each component are as follows: the rear fixing frame 512 is fixed to the front end of the rear lens tube 517 by a threaded connection, the focusing lens frame 516 is axially movable at the rear end of the rear lens tube 517 by a focusing guide pin, and the reflecting mirror mount 505 is fastened to both the front lens frame 507 and the rear lens tube 517 by screws to form a complete optical path support structure.

[0045] Specifically, the filter 101 is bonded and fixed inside the front pressure ring 501 using Nanda adhesive; a first spacer 503 is installed between the first biconvex lens 102 and the first biconcave lens 103, and a second spacer 504 is installed between the first biconcave lens 103 and the first plano-convex lens 104. The above three lenses and spacers are pressed and fixed inside the front frame 507 by the front pressure ring 501 and the front gasket 502.

[0046] Specifically, the plane mirror 20 is pressed and fixed inside the mirror frame 506 by the mirror frame pressure plate 508, and the mirror frame 506 is then fastened to the mirror seat 505 by screws; a third spacer 510 is installed between the second biconvex lens 301 and the first meniscus lens 302, and a fourth spacer 511 is installed between the first meniscus lens 302 and the second meniscus lens 303. The above three lenses and spacers are pressed and fixed inside the rear fixing frame 512 by the rear fixing pressure ring 509.

[0047] Specifically, a fifth spacer 513 is installed between the third biconvex lens 401 and the second biconcave lens 402. The two lenses and the spacer are pressed and fixed inside the focusing frame 516 by the focusing pad 514 and the focusing pressure ring 515.

[0048] Specifically, the physical parameters of each optical element in the wide temperature range large target surface high-definition near-infrared lens provided in Example 1 are shown in Table 1 below, where the radius of curvature and thickness are in mm.

[0049] Table 1

[0050] Specifically, the optical system parameters of the wide temperature range, large target surface, high-definition near-infrared lens provided in Example 1 are as follows: operating wavelength range of 600nm to 900nm, focal length of 107.54mm, total optical length of 178mm, field of view of 9.58°×9.58°, exit pupil distance of 59mm, exit pupil diameter of 22mm, and optical distortion ≤0.19%; operating temperature range of -55 to 85℃, near-field measurement distance of 10m; compatible imaging target surface size of 4096×4096, single pixel size of 4.4μm, and lens diagonal image height of 27.2mm.

[0051] When the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens operates in an environment of -55℃, the focusing group 40 moves axially 4.44mm towards the image plane; when the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens operates in an environment of 85℃, the focusing group 40 moves axially 3.68mm away from the image plane; when the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens observes a 10m close-up target, the focusing group 40 moves axially 2.84mm away from the image plane.

[0052] Please see Figures 3 to 5 , Figures 3 to 5 The images show the dot plot, transfer function plot, and field curvature / distortion plot of the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens in Example 1 at room temperature. Figure 3 As can be seen from the dot plot, the light rays from each aperture band and each field of view are focused onto the image plane in the lens of Example 1, resulting in a smaller spot size; Figure 4 As can be seen from the transfer function diagram, the transfer function of the wide-temperature-range, large-target-area, high-definition near-infrared fixed-focus lens of Example 1 is >0.42 across the entire field of view at 111 lp / mm in the near-infrared band; Figure 5 The field curvature / distortion diagram shows that the system astigmatism of the wide-temperature-range, large-target-area, high-definition near-infrared fixed-focus lens in Example 1 is small, and the maximum distortion is less than 0.19%. This indicates that the lens aberration has been effectively corrected, and the resolution is excellent, resulting in high-definition imaging.

[0053] Please see Figures 6 to 7 , Figure 6 , Figure 7 The diagram shows the dot plot and transfer function of the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens provided in Example 1 at a temperature of -55°C. Figure 6 As can be seen from the dot plot, the light rays from each aperture band and each field of view are focused onto the image plane at smaller spots after passing through the lens in the embodiment; Figure 7 As can be seen from the transfer function diagram, the wide temperature range large target area high-definition near-infrared fixed-focus lens of Example 1 has a transfer function of >0.4 in the near-infrared band at 111 lp / mm, indicating that the lens has excellent performance in a temperature environment of -55℃.

[0054] Please see Figures 8 to 9 , Figure 8 , Figure 9 The diagram shows the dot plot and transfer function of the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens provided in Example 1 at an 85°C temperature. Figure 8 As can be seen from the dot plot, the light rays from each aperture band and each field of view are focused onto the image plane at smaller spots after passing through the lens in the embodiment; Figure 9 As can be seen from the transfer function diagram, the wide temperature range large target area high-definition near-infrared fixed-focus lens of Example 1 has a transfer function of >0.4 in the near-infrared band at 111 lp / mm, indicating that the lens performs well in an environment with a temperature of 85℃.

[0055] Please see Figures 10 to 11 , Figure 10 , Figure 11 The diagram shows the point plot and transfer function of the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens provided in Example 1 when observing a close-up scene at 10m. Figure 10 As can be seen from the dot plot, the light rays from each aperture band and each field of view are focused onto the image plane at smaller spots after passing through the lens in the embodiment; Figure 11 As can be seen from the transfer function diagram, the wide temperature range, large target surface, high-definition near-infrared fixed-focus lens provided in Example 1 has a transfer function of >0.4 in the entire field of view at 111 lp / mm in the near-infrared band, indicating that the lens has excellent performance when the object distance is 10 to ∞m.

[0056] Compared with the prior art, the present invention has the following advantages: First, the wide temperature range large target surface high-definition near-infrared fixed-focus lens provided in the embodiments of the present invention has excellent high-definition imaging performance. The lens has a diagonal image height of 27.2mm, can be equipped with a large target surface camera with a resolution of 4096×4096, and the camera pixel is 4.4μm, which can meet the high-definition imaging requirements of the lens. Second, the wide temperature range large target area high-definition near-infrared fixed-focus lens provided in the embodiments of the present invention has excellent imaging performance in a wide temperature range of -55 to 85℃ and can maintain good optical performance when working in extreme environments. Third, the wide temperature range, large target area, high-definition near-infrared fixed-focus lens provided in this embodiment of the invention has no glued parts, thus eliminating the problem of glue separation at the source and making it highly practical.

[0057] 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.

[0058] 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 near-infrared lens, characterized in that, It includes a front fixed group, a plane mirror, a rear fixed group, and a focusing group arranged sequentially along the direction of light incidence; The front fixed group is used to receive incident light, and to initially focus the incident light and correct primary aberrations and chromatic aberrations; the plane mirror is used to deflect the light path to compress the lens structure size; the rear fixed group is used to further correct residual aberrations of the system to adapt to high-definition imaging of large target surfaces; the focusing group is movable along the optical axis to compensate for high and low temperature drift and close-up focusing deviation, so as to achieve stable imaging of the image plane in a wide temperature range.

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

3. The wide temperature range, large target area, high-definition near-infrared fixed-focus lens according to claim 2, characterized in that, The front fixing group includes a filter, a first biconvex lens, a first biconcave lens and a first plano-convex lens arranged sequentially along the light incident direction; The air gap between the filter and the first biconvex lens is 0.9–1.1 mm, the air gap between the first biconvex lens and the first biconcave lens is 1.45–1.5 mm, the air gap between the first biconcave lens and the first plano-convex lens is 0.7–0.75 mm, and the air gap between the first plano-convex lens and the center of the plane mirror is 28–30 mm.

4. The wide temperature range, large target area, high-definition near-infrared fixed-focus lens according to claim 3, characterized in that, The rear fixing group includes a second biconvex lens, a first meniscus lens, and a second meniscus lens arranged sequentially along the incident direction of light. The air gap between the center of the plane mirror and the second biconvex lens is 19-21 mm; the air gap between the second biconvex lens and the first meniscus lens is 0.7-0.8 mm; and the air gap between the first meniscus lens and the second meniscus lens is 4.5-5 mm.

5. The wide temperature range, large target area, high-definition near-infrared fixed-focus lens according to claim 4, characterized in that, The focusing group includes a third biconvex lens and a second biconcave lens arranged sequentially along the incident direction of light; wherein the air gap between the second meniscus lens and the third biconvex lens is 4-5 mm, and the air gap between the third biconvex lens and the second biconcave lens is 0.7-0.75 mm.

6. The wide temperature range, large target area, high-definition near-infrared fixed-focus lens according to claim 5, characterized in that, The refractive indices and Abbe numbers of the optical elements in the front fixed group, the plane mirror, the rear fixed group, and the focusing group satisfy the following conditions: 1.5<n1<1.55, 60<V1<70; 1.55<n2<1.6, 60<V2<70; 1.65<n3<1.7, 35<V3<45; 1.55<n4<1.6, 70<V4<80; 1.5<n5<1.55, 60<V5<70; 1.6<n6<1.65, 50<V6<60; 1.65<n7<1.7, 50<V7<60; 1.55<n8<1.6, 55<V8<65; 1.75 < n9 < 1.8, 45 < V9 < 55; 1.55 < n 10 < 1.6, 35 < V 10 < 45; wherein n1, n2, n3, n4, n5, n6, n7, n8, n9 and n 10 Abbe numbers of the filter, the first biconvex lens, the first biconcave lens, the first plano-convex lens, the plane mirror, the second biconvex lens, the first meniscus lens, the second meniscus lens, the third biconvex lens and the second biconcave lens, respectively; V1, V2, V3, V4, V5, V6, V7, V8, V9 and V 10 Abbe numbers of the filter, the first biconvex lens, the first biconcave lens, the first plano-convex lens, the plane mirror, the second biconvex lens, the first meniscus lens, the second meniscus lens, the third biconvex lens and the second biconcave lens, respectively.

7. The wide temperature range, large target area, high-definition near-infrared fixed-focus lens according to claim 6, characterized in that, The focal length f2 of the first biconvex lens is 63mm < f2 < 70mm; the focal length f3 of the first biconcave lens is -71mm < f3 < -63mm; the focal length f4 of the first plano-convex lens is 101mm < f4 < 113mm; the focal length f6 of the second biconvex lens is 45mm < f6 < 51mm; the focal length f7 of the first meniscus lens is -68mm < f7 < -60mm; the focal length f8 of the second meniscus lens is -54mm < f8 < -48mm; the focal length f9 of the third biconvex lens is 32mm < f9 < 37mm; the focal length f2 of the second biconcave lens is 70mm < f2 < 70mm; the focal length f3 of the second biconcave lens is -71mm < f3 < -63mm; the focal length f4 of the first plano-convex lens is 101mm < f4 < 113mm; the focal length f6 of the second biconvex lens is 45mm < f6 < 51mm; the focal length f7 of the first meniscus lens is -68mm < f7 < -60mm; the focal length f8 of the second meniscus lens is -54mm < f8 < -48mm; the focal length f9 of the third biconvex lens is 32mm < f9 < 37mm; the focal length f6 of the second biconcave lens is 70mm < f2 < 70mm; the focal length f7 of the second meniscus lens is -71mm < f3 < -63mm; the focal length f8 of the second meniscus lens is -54mm < f8 < -48mm; the focal length f9 of the third biconvex lens is 32mm < f9 < 37mm; the focal length f9 of the second biconcave lens is 70mm < f2 < 70mm; the focal length f 10 -47mm < f 10 <-41mm.

8. The wide temperature range, large target area, high-definition near-infrared fixed-focus lens according to claim 1, characterized in that, The optical elements in the front fixing group, the rear fixing group, and the focusing group are all made of CDGM standard optical glass material.

9. The wide temperature range, large target area, high-definition near-infrared fixed-focus lens according to any one of claims 1 to 8, characterized in that, The optical system parameters of the wide temperature range, large target surface, high-definition near-infrared fixed-focus lens are as follows: operating wavelength range of 600nm~900nm, focal length of 107.54mm, total optical length of 178mm, field of view of 9.58°×9.58°, exit pupil distance of 59mm, exit pupil diameter of 22mm, optical distortion ≤0.19%; operating temperature range of -55~85℃, near-field measurement distance of 10m; compatible imaging target surface size of 4096×4096, single pixel size of 4.4μm, and lens diagonal image height of 27.2mm.

10. The wide temperature range, large target area, high-definition near-infrared fixed-focus lens according to claim 9, characterized in that, When the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens operates in an environment of -55℃, the focusing group moves axially 4.44mm closer to the image plane; when the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens operates in an environment of 85℃, the focusing group moves axially 3.68mm further away from the image plane; when the wide-temperature-range, large-area, high-definition near-infrared fixed-focus lens observes a 10m close-up target, the focusing group moves axially 2.84mm further away from the image plane.

Images