A long focal length high-definition imaging optical system

Abstract

This invention provides a long-focal-length high-definition imaging optical system, comprising a first plano-concave lens, a first meniscus lens, a first plano-convex lens, a first biconvex lens, a second biconvex lens, a first biconcave lens, a second biconcave lens, a third biconvex lens, a second plano-convex lens, a fourth biconvex lens, a second plano-concave lens, and a second meniscus lens. The first meniscus lens and the first plano-convex lens, the second biconvex lens and the first biconcave lens, the second biconcave lens and the third biconvex lens, and the fourth biconvex lens and the second plano-concave lens constitute four sets of cemented lenses. The four sets of cemented lenses are paired with high-refractive-index, low-Abbe-number materials and low-refractive-index, high-Abbe-number materials to compensate for the dispersion differences between the visible and near-infrared bands, making the imaging of the two bands coplanar. The plano-concave and biconcave lenses efficiently correct fundamental aberrations. The meniscus lens flexibly adjusts the field curvature, effectively improving the edge imaging quality and avoiding the problem of sharp centers and blurred edges at high pixel counts.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and in particular to a long focal length high-definition imaging optical system. Background Technology

[0002] With the popularization of high-pixel imaging technology, extremely high requirements are placed on the resolution, distortion control, and chromatic aberration suppression of lenses. At the same time, security, automotive, and industrial inspection scenarios require lenses to maintain a consistent focus plane in both visible light (daytime) and near-infrared (nighttime) bands, i.e., day and night co-focus, to avoid refocusing when imaging at night.

[0003] Current high-pixel lenses produce clear images in the central area but blurry images at the edges, resulting in significant edge image quality degradation. Furthermore, the focal planes of visible light and near-infrared bands are offset, making it impossible to achieve true day and night co-focus. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a long focal length high-definition imaging optical system that can avoid the problem of sharp center and blurred edges under high pixel count, and can also avoid the problem of focal plane drift in the visible light and near-infrared bands, thereby improving the long-term reliability of day and night confocal performance.

[0005] This invention is implemented as follows: The present invention provides a long focal length high-definition imaging optical system, comprising a first plano-concave lens, a first meniscus lens, a first plano-convex lens, a first biconvex lens, a second biconvex lens, a first biconcave lens, a second biconcave lens, a third biconvex lens, a second plano-convex lens, a fourth biconvex lens, a second plano-concave lens, and a second meniscus lens arranged sequentially from the object side to the image side. The first meniscus lens and the first plano-convex lens form a first cemented lens; the second biconvex lens and the first biconcave lens form a second cemented lens; the second biconcave lens and the third biconvex lens form a third cemented lens; and the fourth biconvex lens and the second plano-concave lens form a fourth cemented lens. The first meniscus lens has a refractive index of 1.6 and an Abbe number of 65. The first plano-convex lens has a refractive index of 1.6 and an Abbe number of 60. The second biconvex lens has a refractive index of 1.7 and an Abbe number of 28. The first biconcave lens has a refractive index of 1.8 and an Abbe number of 37. The second biconcave lens has a refractive index of 1.7 and an Abbe number of 31. The third biconvex lens has a refractive index of 1.6 and an Abbe number of 61. The fourth biconvex lens has a refractive index of 1.7 and an Abbe number of 32. The second plano-concave lens has a refractive index of 1.6 and an Abbe number of 65.

[0006] Furthermore, the first plano-concave lens has a refractive index of 1.6 and an Abbe number of 65; The first biconvex lens has a refractive index of 1.6 and an Abbe number of 61. The second plano-convex lens has a refractive index of 1.8 and an Abbe number of 37. The second meniscus lens has a refractive index of 1.6 and an Abbe number of 65.

[0007] Furthermore, the radius of curvature R1 of the object side of the first plano-concave lens is: -120mm≤R1≤-110mm, and the image side of the first plano-concave lens is a plane; The radius of curvature R1 of the object side of the first meniscus lens is: 75mm≤R1≤85mm, and the radius of curvature R2 of the image side of the first meniscus lens is: 35mm≤R2≤40mm. The radius of curvature R1 of the object-side surface of the first plano-convex lens is: 35mm≤R1≤40mm, and the image-side surface of the first plano-convex lens is a plane; The radius of curvature R1 of the object side of the first biconvex lens is: 35mm≤R1≤40mm, and the radius of curvature R2 of the image side of the first biconvex lens is: 510mm≤R2≤520mm. The radius of curvature R1 of the object side of the second biconvex lens is: 30mm≤R1≤35mm, and the radius of curvature R2 of the image side of the second biconvex lens is: -160mm≤R2≤-155mm. The radius of curvature R1 of the object side of the first biconcave lens is: -160mm≤R1≤-155mm, and the radius of curvature R2 of the image side of the first biconcave lens is: 18mm≤R2≤22mm. The radius of curvature R1 of the object side of the second biconcave lens is: -22mm≤R1≤-18mm, and the radius of curvature R2 of the image side of the second biconcave lens is: 105mm≤R2≤115mm. The radius of curvature R1 of the object side of the third biconvex lens is: -40mm≤R1≤-30mm, and the radius of curvature R2 of the image side of the third biconvex lens is: 105mm≤R2≤110mm. The object-side surface of the second plano-convex lens is a plane, and the radius of curvature R2 of the image-side surface of the second plano-convex lens is: -42mm≤R2≤-38mm; The radius of curvature R1 of the object side of the fourth biconvex lens is: 385mm≤R1≤390mm, and the radius of curvature R2 of the image side of the fourth biconvex lens is: -50mm≤R2≤-45mm. The radius of curvature R1 of the object side of the second plano-concave lens is: -50mm≤R1≤-45mm, and the image side of the second plano-concave lens is a plane; The radius of curvature R1 of the object side of the second meniscus lens is: -56mm≤R1≤-50mm, and the radius of curvature R2 of the image side of the second meniscus lens is: -100mm≤R2≤-90mm.

[0008] Furthermore, the air gap D1 between the first plano-concave lens and the first cemented lens is: 0.2mm≤D1≤0.4mm; The air gap D2 between the first cemented lens and the first biconvex lens is: 0.2mm ≤ D2 ≤ 0.4mm; The air gap D3 between the first biconvex lens and the second cemented lens is: 0.2mm≤D3≤0.4mm; The air gap D4 between the second cemented lens and the third cemented lens is: 20mm≤D4≤23mm; The air gap D5 between the third cemented lens and the second plano-convex lens is: 0.2mm ≤ D5 ≤ 0.4mm; The air gap D6 between the second plano-convex lens and the fourth cemented lens is: 10mm≤D6≤14mm; The air gap D7 between the fourth cemented lens and the second meniscus lens is: 5mm≤D6≤8mm.

[0009] Furthermore, a plane lens is also provided between the second meniscus lens and the image side.

[0010] The beneficial effects of this invention are as follows: plano-concave and biconcave lenses efficiently correct fundamental aberrations such as spherical aberration and coma; the meniscus lens flexibly adjusts field curvature, effectively improving edge imaging quality and avoiding the problem of sharp centers and blurred edges in high-pixel images, resulting in a lens center MTF ≥ 0.2@160lp / mm and an edge MTF ≥ 0.2@140lp / mm, meeting the high-resolution requirements of high-pixel-level small-size pixel sensors. The multi-faceted lens combination and multi-cemented design can systematically correct spherical aberration, coma, field curvature, distortion, and chromatic aberration, resulting in lens distortion ≤ 0.2%, edge relative illumination ≥ 60%, and excellent imaging uniformity and fidelity.

[0011] Furthermore, multiple cemented lenses reduce air interface reflection losses, improve overall light transmittance and imaging contrast, ensure the high signal-to-noise ratio required for high-pixel imaging, and suppress stray light and artifacts. The four cemented lenses are paired with high-refractive-index, low-Abbe-number materials and low-refractive-index, high-Abbe-number materials to systematically compensate for the dispersion differences in the visible light (430–650 nm) and near-infrared (800–950 nm) bands, ensuring that the principal rays of both bands converge on the same image plane. Focal plane shift is ≤0.02 mm, eliminating the need for nighttime refocusing and achieving stable imaging in all weather conditions. Moreover, the cemented structure fixes the relative positions of the lenses, preventing focal plane drift caused by changes in air gaps and improving the long-term reliability of day and night confocal performance. Attached Figure Description

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0013] Figure 1 This is a schematic diagram of the optical lens of a long focal length high-definition imaging optical system according to the present invention.

[0014] Figure 2 The radius of curvature is the object side and image side of each lens in this invention.

[0015] Figure 3 This refers to the air gap between two adjacent lenses in this invention.

[0016] Figure 4 These represent the refractive index and Abbe number of each lens in this invention.

[0017] Figure 5 This is an MTF diagram of a long focal length high-definition imaging optical system according to the present invention.

[0018] Figure 6 This is a standard dot matrix diagram of a long focal length high-definition imaging optical system according to the present invention.

[0019] Figure 7 This is a field curvature and F-Theta distortion diagram of a long focal length high-definition imaging optical system according to the present invention.

[0020] Figure 8 This invention provides a light fan for a long focal length high-definition imaging optical system. Figure 1 .

[0021] Figure 9 This invention provides a light fan for a long focal length high-definition imaging optical system. Figure 2 .

[0022] Figure 10 This invention provides a light fan for a long focal length high-definition imaging optical system. Figure 3 .

[0023] Figure 11 This invention provides a light fan for a long focal length high-definition imaging optical system. Figure 4 .

[0024] Figure 12 This invention provides a light fan for a long focal length high-definition imaging optical system. Figure 5 .

[0025] Figure 13 This invention provides a light fan for a long focal length high-definition imaging optical system. Figure 6 .

[0026] Figure 14 This invention provides a light fan for a long focal length high-definition imaging optical system. Figure 7 .

[0027] Explanation of the labels in the diagram: 1. First plano-concave lens; 2. First meniscus lens; 3. First plano-convex lens; 4. First biconvex lens; 5. Second biconvex lens; 6. First biconcave lens; 7. Second biconcave lens; 8. Third biconvex lens; 9. Second plano-convex lens; 10. Fourth biconvex lens; 11. Second plano-concave lens; 12. Second meniscus lens; 13. Plane lens. Detailed Implementation

[0028] Please see Figures 1 to 14 The present invention provides a long focal length high-definition imaging optical system, comprising a first plano-concave lens 1, a first meniscus lens 2, a first plano-convex lens 3, a first biconvex lens 4, a second biconvex lens 5, a first biconcave lens 6, a second biconcave lens 7, a third biconvex lens 8, a second plano-convex lens 9, a fourth biconvex lens 10, a second plano-concave lens 11, and a second meniscus lens 12 arranged sequentially from the object side to the image side. Among the aforementioned lenses, plano-convex and biconvex lenses provide stable positive optical power, achieving a target focal length of 90mm. Plano-concave and biconcave lenses efficiently correct fundamental aberrations such as spherical aberration and coma. The meniscus lens flexibly adjusts field curvature, effectively improving edge imaging quality and avoiding the problem of sharp centers and blurred edges under high pixel counts. This results in a center MTF ≥ 0.2@160lp / mm and an edge MTF ≥ 0.2@140lp / mm, meeting the high resolution requirements of high-pixel-level small-size pixel sensors.

[0029] The first meniscus lens 2 and the first plano-convex lens 3 form a first cemented lens; the second biconvex lens 5 and the first biconcave lens 6 form a second cemented lens; the second biconcave lens 7 and the third biconvex lens 8 form a third cemented lens; and the fourth biconvex lens 10 and the second plano-concave lens 11 form a fourth cemented lens. The optical power of the first plano-concave lens 1 is negative, the optical power of the first cemented lens is positive, the optical power of the first biconvex lens 4 is positive, the optical power of the second cemented lens is negative, the optical power of the third cemented lens is negative, the optical power of the second plano-convex lens 9 is positive, the optical power of the fourth cemented lens is positive, and the optical power of the second meniscus lens 12 is negative. By combining the optical powers of the above lenses, an optical system can be achieved with a focal length of 90mm ± 3%, image quality across the entire 4' field of view, a resolution of 8MP, an f-number of 4.4, distortion <0.2%, and an MTF (modulation transfer function) greater than 0.2 at 140mm / lp.

[0030] The first meniscus lens 2 has a refractive index of 1.6 and an Abbe number of 65. The first plano-convex lens 3 has a refractive index of 1.6 and an Abbe number of 60; The second biconvex lens 5 has a refractive index of 1.7 and an Abbe number of 28. The first biconcave lens 6 has a refractive index of 1.8 and an Abbe number of 37. The second biconcave lens 7 has a refractive index of 1.7 and an Abbe number of 31. The third biconvex lens 8 has a refractive index of 1.6 and an Abbe number of 61. The fourth biconvex lens 10 has a refractive index of 1.7 and an Abbe number of 32. The second plano-concave lens 11 has a refractive index of 1.6 and an Abbe number of 65.

[0031] Specifically, the first plano-concave lens 1 has a refractive index of 1.6 and an Abbe number of 65; The first biconvex lens 4 has a refractive index of 1.6 and an Abbe number of 61. The second plano-convex lens 9 has a refractive index of 1.8 and an Abbe number of 37. The second meniscus lens 12 has a refractive index of 1.6 and an Abbe number of 65.

[0032] Specifically, the radius of curvature R1 of the object side of the first plano-concave lens 1 is: -120mm≤R1≤-110mm, and the image side of the first plano-concave lens 1 is a plane; The radius of curvature R1 of the object side of the first meniscus lens 2 is: 75mm≤R1≤85mm, and the radius of curvature R2 of the image side of the first meniscus lens 2 is: 35mm≤R2≤40mm. The radius of curvature R1 of the object side of the first plano-convex lens 3 is: 35mm≤R1≤40mm, and the image side of the first plano-convex lens 3 is a plane; The radius of curvature R1 of the object side of the first biconvex lens 4 is: 35mm≤R1≤40mm, and the radius of curvature R2 of the image side of the first biconvex lens 4 is: 510mm≤R2≤520mm. The radius of curvature R1 of the object side of the second biconvex lens 5 is: 30mm≤R1≤35mm, and the radius of curvature R2 of the image side of the second biconvex lens 5 is: -160mm≤R2≤-155mm. The radius of curvature R1 of the object side of the first biconcave lens 6 is: -160mm≤R1≤-155mm, and the radius of curvature R2 of the image side of the first biconcave lens 6 is: 18mm≤R2≤22mm. The radius of curvature R1 of the object side of the second biconcave lens 7 is: -22mm≤R1≤-18mm, and the radius of curvature R2 of the image side of the second biconcave lens 7 is: 105mm≤R2≤115mm. The radius of curvature R1 of the object side of the third biconvex lens 8 is: -40mm≤R1≤-30mm, and the radius of curvature R2 of the image side of the third biconvex lens 8 is: 105mm≤R2≤110mm. The object side of the second plano-convex lens 9 is a plane, and the radius of curvature R2 of the image side of the second plano-convex lens 9 is: -42mm≤R2≤-38mm; The radius of curvature R1 of the object side of the fourth biconvex lens 10 is: 385mm≤R1≤390mm, and the radius of curvature R2 of the image side of the fourth biconvex lens 10 is: -50mm≤R2≤-45mm. The radius of curvature R1 of the object side of the second plano-concave lens 11 is: -50mm≤R1≤-45mm, and the image side of the second plano-concave lens 11 is a plane; The radius of curvature R1 of the object side of the second meniscus lens 12 is: -56mm≤R1≤-50mm, and the radius of curvature R2 of the image side of the second meniscus lens 12 is: -100mm≤R2≤-90mm.

[0033] Specifically, the air gap D1 between the first plano-concave lens 1 and the first cemented lens is: 0.2mm≤D1≤0.4mm; The air gap D2 between the first cemented lens and the first biconvex lens 4 is: 0.2mm≤D2≤0.4mm; The air gap D3 between the first biconvex lens 4 and the second cemented lens is: 0.2mm≤D3≤0.4mm; The air gap D4 between the second cemented lens and the third cemented lens is: 20mm≤D4≤23mm; The air gap D5 between the third cemented lens and the second plano-convex lens 9 is: 0.2mm≤D5≤0.4mm; The air gap D6 between the second plano-convex lens 9 and the fourth cemented lens is: 10mm≤D6≤14mm; The air gap D7 between the fourth cemented lens and the second meniscus lens 12 is: 5mm≤D6≤8mm.

[0034] Specifically, a plane lens 13 is also provided between the second meniscus lens 12 and the image side.

[0035] In this invention, plano-convex and biconvex lenses provide stable positive optical power, accurately achieving a target focal length of 90mm; plano-concave and biconcave lenses are used to efficiently correct fundamental aberrations such as spherical aberration and coma; the meniscus lens can flexibly adjust field curvature, effectively improving edge imaging quality and avoiding the problem of sharp centers and blurred edges in high-pixel sensors, ensuring a center MTF ≥ 0.2@160lp / mm and an edge MTF ≥ 0.2@140lp / mm, meeting the high-resolution requirements of high-pixel-level small-size pixel sensors. Multiple sets of cemented lenses reduce air interface reflection loss, improve overall transmittance and imaging contrast, ensure the high signal-to-noise ratio required for high-pixel imaging, and suppress stray light and artifacts.

[0036] A cemented lens system comprises four groups: a first meniscus lens 2 and a first plano-convex lens 3, a second biconvex lens 5 and a first biconcave lens 6, a second biconcave lens 7 and a third biconvex lens 8, a fourth biconvex lens 10, and a second plano-concave lens 11. This system uses a combination of high-refractive-index, low-Abbe-number and low-refractive-index, high-Abbe-number materials to systematically compensate for the dispersion differences between the visible light (430–650 nm) and near-infrared (800–950 nm) bands. This ensures that the principal rays of both bands converge onto the same image plane, with a focal plane shift of ≤0.02 mm. This eliminates the need for nighttime refocusing, achieving stable imaging in all weather conditions. The cemented structure fixes the relative positions of the lenses, preventing focal plane drift caused by changes in air gaps and improving the long-term reliability of the day-night confocal performance.

[0037] This invention utilizes a multi-faceted combination of plano-concave, plano-convex, biconcave, biconvex, and meniscus lenses, along with a multi-set cemented design, to systematically correct spherical aberration, coma, field curvature, distortion, and chromatic aberration. This results in lens distortion ≤0.2%, edge relative illumination ≥60%, and excellent image uniformity and fidelity. Furthermore, the modular structure allows for reasonable tolerances in the radius of curvature and thickness of individual lenses. These tolerances are offset by the overall assembly, reducing the precision requirements for individual component manufacturing, decreasing processing difficulty and scrap rate, and effectively controlling mass production costs. The 12-lens optical system has a compact and rational structure. Its back focal length and total lens length meet the integration requirements of cameras, security monitoring, industrial inspection, and other equipment, while also being compatible with large-size sensors, making it suitable for a wide range of applications. By using a combination of negative positive positive negative negative negative positive positive negative, a system focal length of 90mm ± 3% can be achieved, with the same image quality across the entire 4' field of view, a resolution of 8MP, an F-number of 4.4, distortion <0.2%, and an MTF (modulation transfer function) greater than 0.2 at 140mm / lp.

[0038] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A long focal length high-definition imaging optical system, characterized in that: It includes a first plano-concave lens, a first meniscus lens, a first plano-convex lens, a first biconvex lens, a second biconvex lens, a first biconcave lens, a second biconcave lens, a third biconvex lens, a second plano-convex lens, a fourth biconvex lens, a second plano-concave lens, and a second meniscus lens arranged sequentially from the object side to the image side. The first meniscus lens and the first plano-convex lens form a first cemented lens; the second biconvex lens and the first biconcave lens form a second cemented lens; the second biconcave lens and the third biconvex lens form a third cemented lens; and the fourth biconvex lens and the second plano-concave lens form a fourth cemented lens. The first meniscus lens has a refractive index of 1.6 and an Abbe number of 65. The first plano-convex lens has a refractive index of 1.6 and an Abbe number of 60. The second biconvex lens has a refractive index of 1.7 and an Abbe number of 28. The first biconcave lens has a refractive index of 1.8 and an Abbe number of 37. The second biconcave lens has a refractive index of 1.7 and an Abbe number of 31. The third biconvex lens has a refractive index of 1.6 and an Abbe number of 61. The fourth biconvex lens has a refractive index of 1.7 and an Abbe number of 32. The second plano-concave lens has a refractive index of 1.6 and an Abbe number of 65.

2. The long focal length high-definition imaging optical system as described in claim 1, characterized in that: The first plano-concave lens has a refractive index of 1.6 and an Abbe number of 65. The first biconvex lens has a refractive index of 1.6 and an Abbe number of 61. The second plano-convex lens has a refractive index of 1.8 and an Abbe number of 37. The second meniscus lens has a refractive index of 1.6 and an Abbe number of 65.

3. The long focal length high-definition imaging optical system as described in claim 1, characterized in that: The radius of curvature R1 of the object side of the first plano-concave lens is: -120mm≤R1≤-110mm, and the image side of the first plano-concave lens is a plane; The radius of curvature R1 of the object side of the first meniscus lens is: 75mm≤R1≤85mm, and the radius of curvature R2 of the image side of the first meniscus lens is: 35mm≤R2≤40mm. The radius of curvature R1 of the object-side surface of the first plano-convex lens is: 35mm≤R1≤40mm, and the image-side surface of the first plano-convex lens is a plane; The radius of curvature R1 of the object side of the first biconvex lens is: 35mm≤R1≤40mm, and the radius of curvature R2 of the image side of the first biconvex lens is: 510mm≤R2≤520mm. The radius of curvature R1 of the object side of the second biconvex lens is: 30mm≤R1≤35mm, and the radius of curvature R2 of the image side of the second biconvex lens is: -160mm≤R2≤-155mm. The radius of curvature R1 of the object side of the first biconcave lens is: -160mm≤R1≤-155mm, and the radius of curvature R2 of the image side of the first biconcave lens is: 18mm≤R2≤22mm. The radius of curvature R1 of the object side of the second biconcave lens is: -22mm≤R1≤-18mm, and the radius of curvature R2 of the image side of the second biconcave lens is: 105mm≤R2≤115mm. The radius of curvature R1 of the object side of the third biconvex lens is: -40mm≤R1≤-30mm, and the radius of curvature R2 of the image side of the third biconvex lens is: 105mm≤R2≤110mm. The object-side surface of the second plano-convex lens is a plane, and the radius of curvature R2 of the image-side surface of the second plano-convex lens is: -42mm≤R2≤-38mm; The radius of curvature R1 of the object side of the fourth biconvex lens is: 385mm≤R1≤390mm, and the radius of curvature R2 of the image side of the fourth biconvex lens is: -50mm≤R2≤-45mm. The radius of curvature R1 of the object side of the second plano-concave lens is: -50mm≤R1≤-45mm, and the image side of the second plano-concave lens is a plane; The radius of curvature R1 of the object side of the second meniscus lens is: -56mm≤R1≤-50mm, and the radius of curvature R2 of the image side of the second meniscus lens is: -100mm≤R2≤-90mm.

4. The long focal length high-definition imaging optical system as described in claim 1, characterized in that: The air gap D1 between the first plano-concave lens and the first cemented lens is: 0.2mm≤D1≤0.4mm; The air gap D2 between the first cemented lens and the first biconvex lens is: 0.2mm ≤ D2 ≤ 0.4mm; The air gap D3 between the first biconvex lens and the second cemented lens is: 0.2mm≤D3≤0.4mm; The air gap D4 between the second cemented lens and the third cemented lens is: 20mm≤D4≤23mm; The air gap D5 between the third cemented lens and the second plano-convex lens is: 0.mm2≤D5≤0.4mm; The air gap D6 between the second plano-convex lens and the fourth cemented lens is: 10mm≤D6≤14mm; The air gap D7 between the fourth cemented lens and the second meniscus lens is: 5mm≤D6≤8mm.

5. The long focal length high-definition imaging optical system as described in claim 1, characterized in that: A plane lens is also provided between the second meniscus lens and the image side.

Images