A long focal length lens

Abstract

The application discloses a long-focus lens, comprising: a first lens group and a second lens group arranged in sequence along an optical axis from an object side to an image side, the first lens group comprising a convex-concave first lens with positive refractive power, a double-concave second lens with negative refractive power and a third lens with positive refractive power; the second lens group comprising a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens; the long-focus lens satisfies the following condition: (D1*180°) / (H*DFOV) >= 2.9, wherein DFOV is a maximum field of view angle of the long-focus lens, D1 is a maximum light aperture of an object side of the first lens corresponding to the maximum field of view angle of the long-focus lens, and H is an image height corresponding to the maximum field of view angle of the long-focus lens. Through reasonable collocation of the lenses, the imaging quality of the long-focus lens is effectively improved, and the long-focus lens has a longer detection distance.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, and more particularly to a telephoto lens. Background Technology

[0002] Advanced Driver Assistance Systems (ADAS) are active safety control systems that utilize sensors installed on the vehicle to continuously sense the surrounding environment and collect data during driving. They identify, detect, and track static and dynamic objects, and combine this data with navigation map data to perform system calculations and analysis. This allows the driver to anticipate potential dangers, effectively increasing driving comfort and safety. This, in turn, places certain demands on the detection range of the camera.

[0003] Optical lenses for general automotive applications typically have very high performance requirements, while those for autonomous driving have even more stringent requirements, needing significant advantages in detection range and resolution. However, existing forward-looking automotive lenses cannot meet the requirements for long-range detection and suffer from poor image quality. Summary of the Invention

[0004] This invention provides a telephoto lens to solve the problems of insufficient detection distance and poor imaging quality of telephoto lenses in related technologies.

[0005] To achieve the above objectives, this invention provides a telephoto lens comprising: a first lens group and a second lens group arranged sequentially from the object side to the image side along the optical axis; the first lens group comprising a convex-concave first lens with positive optical power, a biconcave second lens with negative optical power, and a third lens with positive optical power; the second lens group comprising a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens; the maximum field of view (DFOV) of the telephoto lens, the maximum aperture D1 of the object side of the first lens corresponding to the maximum field of view of the telephoto lens, and the image height H corresponding to the maximum field of view of the telephoto lens satisfying the following: (D1*180°) / (H*DFOV)≥2.9.

[0006] The second lens group includes at least one cemented doublet lens, the object side of the fourth lens is convex, and the image side of the ninth lens is concave.

[0007] Optionally, the fourth lens and the fifth lens are cemented together to form a cemented lens, the sixth lens and the seventh lens are cemented together to form a cemented lens, and the eighth lens and the ninth lens are cemented together to form a cemented lens; The fifth lens has a convex image side, the sixth lens is a biconvex lens, the seventh lens is a biconcave lens, the eighth lens is a biconvex lens, and the ninth lens is a biconcave lens.

[0008] Optionally, the fourth lens, the fifth lens and the sixth lens form a cemented lens, and the seventh lens and the eighth lens form a cemented lens; Wherein, the fourth lens is a biconvex lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a biconvex lens, the eighth lens is a biconcave lens, and the ninth lens is a convex-concave lens.

[0009] Optionally, the fifth lens and the sixth lens form a cemented lens, and the seventh lens, the eighth lens and the ninth lens form a cemented lens; Wherein, the fourth lens is a biconvex lens, the fifth lens is a biconvex lens, the sixth lens is a biconcave lens, the seventh lens is a biconvex lens, the eighth lens is a concave-convex lens, and the ninth lens is a biconcave lens.

[0010] Optionally, the maximum field of view angle DFOV of the telephoto lens, the F-number FNO of the telephoto lens, and the total length TTL of the telephoto lens satisfy the following relational expression: 0.5<DFOV / FNO / TTL<0.7.

[0011] Optionally, the refractive index Nd1 of the first lens satisfies 1.72<Nd1<2.05, and the Abbe number Vd1 of the first lens satisfies 25<Vd1<60; the refractive index Nd2 of the second lens satisfies 1.67<Nd2<1.88, and the Abbe number Vd2 of the second lens satisfies 18<Vd2<35; the refractive index Nd3 of the third lens satisfies 1.82<Nd3<2.03, and the Abbe number Vd3 of the third lens satisfies 15<Vd3<43.

[0012] Optionally, the focal power Φ1 of the first lens and the focal power Φ of the telephoto lens satisfy 0.19≤Φ1 / Φ≤0.55; the focal power Φ2 of the second lens and the focal power Φ of the telephoto lens satisfy -1.76≤Φ2 / Φ≤-1.35; the focal power Φ3 of the third lens and the focal power Φ of the telephoto lens satisfy 0.41≤Φ3 / Φ≤1.13.

[0013] Optionally, the Abbe number Vd5 of the fifth lens satisfies 38<Vd5<64.

[0014] Optionally, the refractive index of the eighth lens satisfies 1.64<Nd8<2.05; the refractive index of the ninth lens satisfies 1.72<Nd9<2.05.

[0015] Optionally, all of the first lens to the ninth lens are glass spherical lenses.

[0016] The telephoto lens proposed in this embodiment of the invention includes: a first lens group and a second lens group arranged sequentially along the optical axis from the object side to the image side. The first lens group includes a convex-concave first lens with positive optical power, a biconcave second lens with negative optical power, and a biconvex third lens with positive optical power. The second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens. The maximum field of view (DFOV) of the telephoto lens, the maximum aperture D1 of the object side of the first lens corresponding to the maximum field of view of the telephoto lens, and the image height H corresponding to the maximum field of view of the telephoto lens satisfy the following condition: (D1*180°) / (H*DFOV)≥2.9. Through the reasonable combination of the lenses, the imaging quality of the telephoto lens is effectively improved, and the telephoto lens has a longer detection distance.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the telephoto lens proposed in an embodiment of the present invention; Figure 2 This is a schematic diagram of the telephoto lens proposed in Embodiment 1 of the present invention; Figure 3 This is the axial aberration diagram of the telephoto lens proposed in Embodiment 1 of the present invention; Figure 4 This is a field curvature distortion diagram of the telephoto lens proposed in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the telephoto lens proposed in Embodiment 2 of the present invention; Figure 6 This is the axial aberration diagram of the telephoto lens proposed in Embodiment 2 of the present invention; Figure 7 This is the field curvature distortion diagram of the telephoto lens proposed in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of the telephoto lens proposed in Embodiment 3 of the present invention; Figure 9 This is the axial aberration diagram of the telephoto lens proposed in Embodiment 3 of the present invention; Figure 10This is the field curvature distortion diagram of the telephoto lens proposed in Embodiment 3 of the present invention; Figure 11 This is a schematic diagram of the telephoto lens proposed in Embodiment 4 of the present invention; Figure 12 This is the axial aberration diagram of the telephoto lens proposed in Embodiment 4 of the present invention; Figure 13 This is a field curvature distortion diagram of a telephoto lens proposed in Embodiment 4 of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of 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 skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0022] Figure 1 This is a schematic diagram of the telephoto lens proposed in an embodiment of the present invention. Figure 1 As shown, the telephoto lens includes: a first lens group and a second lens group arranged sequentially along the optical axis from the object side to the image side. The first lens group includes a convex-concave first lens 1 with positive optical power, a biconcave second lens 2 with negative optical power, and a third lens 3 with positive optical power. The second lens group includes a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, and a ninth lens 9. The second lens group includes at least one cemented doublet lens. The object side of the fourth lens 4 is convex, and the image side of the ninth lens 9 is concave. Through the reasonable combination of these lenses, the imaging quality of the telephoto lens is effectively improved, and the telephoto lens has a longer detection distance. It also facilitates control of the overall length of the telephoto lens and is beneficial for achieving a large target surface and balancing aberrations. It also includes: a combination of a filter and a flat glass plate 10.

[0023] The maximum field of view (DFOV) of the telephoto lens, the maximum aperture D1 of the object side of the first lens 1 corresponding to the maximum field of view of the telephoto lens, and the image height H corresponding to the maximum field of view of the telephoto lens satisfy the following condition: (D1*180°) / (H*DFOV)≥2.9. This is beneficial for controlling the overall length of the lens, obtaining clear images in darker environments, and also for achieving a longer detection distance.

[0024] Optionally, the fourth lens 4 and the fifth lens 5 are cemented together to form a cemented lens, the sixth lens 6 and the seventh lens 7 are cemented together to form a cemented lens, and the eighth lens 8 and the ninth lens 9 are cemented together to form a cemented lens; wherein the image side of the fifth lens 5 is convex, the sixth lens 6 is a biconvex lens, the seventh lens 7 is a biconcave lens, the eighth lens 8 is a biconvex lens, and the ninth lens 9 is a biconcave lens.

[0025] In this configuration, the fourth lens 4 can be a biconvex lens, and the fifth lens 5 can be a concave-convex lens; alternatively, the fourth lens 4 can be a convex-concave lens, and the fifth lens 5 can be a biconvex lens. The use of cemented lenses helps correct chromatic aberration and improves image quality.

[0026] Optionally, the fourth lens 4, the fifth lens 5, and the sixth lens 6 form a cemented lens, and the seventh lens 7 and the eighth lens 8 also form a cemented lens; wherein the fourth lens 4 is a biconvex lens, the fifth lens 5 is a biconcave lens, the sixth lens 6 is a biconvex lens, the seventh lens 7 is a biconvex lens, the eighth lens 8 is a biconcave lens, and the ninth lens 9 is a convex-concave lens. The use of cemented lenses helps correct chromatic aberration in the system and improves the image quality.

[0027] Optionally, the fifth lens 5 and the sixth lens 6 form a cemented lens, and the seventh lens 7, the eighth lens 8, and the ninth lens 9 also form a cemented lens; wherein the fourth lens 4 is a biconvex lens, the fifth lens 5 is a biconvex lens, the sixth lens 6 is a biconcave lens, the seventh lens 7 is a biconvex lens, the eighth lens 8 is a concave-convex lens, and the ninth lens 9 is a biconcave lens. The use of cemented lenses helps correct chromatic aberration in the system and improves the image quality.

[0028] Optionally, the maximum field of view (DFOV) of the telephoto lens, the maximum aperture D1 of the object side of the first lens 1 corresponding to the maximum field of view of the telephoto lens, and the image height H corresponding to the maximum field of view of the telephoto lens satisfy the following relationship: (D1*180°) / (H*DFOV)≥2.9. This is beneficial for controlling the overall length of the lens, obtaining clear images in darker environments, and also for achieving a longer detection distance.

[0029] Optionally, the refractive index Nd1 of the first lens 1 satisfies 1.72<Nd1<2.05, and the Abbe number Vd1 of the first lens 1 satisfies 25<Vd1<60; the refractive index Nd2 of the second lens 2 satisfies 1.67<Nd2<1.88, and the Abbe number Vd2 of the second lens 2 satisfies 18<Vd2<35; the refractive index Nd3 of the third lens 3 satisfies 1.82<Nd3<2.03, and the Abbe number Vd3 of the third lens 3 satisfies 15<Vd3<43.

[0030] Optionally, the focal power Φ1 of the first lens 1 and the focal power Φ of the telephoto lens satisfy 0.19≤Φ1 / Φ≤0.55; the focal power Φ2 of the second lens 2 and the focal power Φ of the telephoto lens satisfy -1.76≤Φ2 / Φ≤-1.35; the focal power Φ3 of the third lens 3 and the focal power Φ of the telephoto lens satisfy 0.41≤Φ3 / Φ≤1.13. Through reasonable selection of the refractive indices and Abbe numbers of the first lens 1, the second lens 2 and the third lens 3, as well as reasonable matching of the focal powers, the light rays from the object plane can be effectively collected and converged into the lens, and the field curvature and distortion of the system can be corrected at the same time.

[0031] Optionally, the Abbe number Vd5 of the fifth lens 5 satisfies 38<Vd5<64, which is beneficial to correcting the chromatic aberration of the system and improving the image quality of the system.

[0032] Optionally, the refractive index of the eighth lens 8 satisfies 1.64<Nd8<2.05; the refractive index of the ninth lens 9 satisfies 1.72<Nd9<2.05, which can effectively converge the light rays from the preceding optical system to make them better converge on the imaging plane.

[0033] Optionally, each of the first lens 1 to the ninth lens 9 is a glass spherical lens.

[0034] In this way, by reasonably distributing parameters such as the material and focal power of each lens, the center thickness of each lens, and the on-axis spacing between the lenses, the aberration of the lens can be reasonably corrected and balanced, the imaging quality of the telephoto lens can be effectively improved, so that it has a longer detection distance, small temperature drift in high and low temperature states, and ensures the imaging quality in high and low temperature states. The present invention adopts a 9-glass optical system structure, and by optimizing the shape, focal power of each lens element and the relative position of each lens element, the design of the telephoto lens with high imaging quality and longer detection distance is finally realized; the telephoto lens has an F-number FNO≥1.6, an optical total length not greater than 40mm, can match a 1 / 1.7-inch chip, and meets the high-definition image quality requirements.

[0035] The telephoto lens proposed in the embodiments of the present invention will be described below with specific embodiments.

[0036] First Embodiment Figure 2This is a schematic diagram of the telephoto lens proposed in Embodiment 1 of the present invention. Figure 2 As shown, the telephoto lens includes a first lens group and a second lens group arranged sequentially from the object side to the image side along the optical axis. The first lens group includes a convex-concave first lens 101 with positive optical power, a biconcave second lens 102 with negative optical power, and a biconvex third lens 103 with positive optical power. The second lens group includes a fourth lens 104, a fifth lens 105, a sixth lens 106, a seventh lens 107, an eighth lens 108, and a ninth lens 109, as well as a combination 110 of a filter and a flat glass plate. The fourth lens 104 and the fifth lens 105 are cemented together to form a cemented lens, the sixth lens 106 and the seventh lens 107 are cemented together to form a cemented lens, and the eighth lens 108 and the ninth lens 109 are cemented together to form a cemented lens. The fourth lens 104 can be a convex-concave lens, the fifth lens 105 can be a biconvex lens, the sixth lens 106 is a biconvex lens, the seventh lens 107 is a biconcave lens, the eighth lens 108 is a biconvex lens, and the ninth lens 109 is a biconcave lens. The relevant parameters of the telephoto lens in Example 1 are shown in Table 1.

[0037] In Example 1, the focal length f of the telephoto lens is 14.2mm, the FNO is 2.0, and the angle corresponding to φ9.8mm is 41.10°.

[0038] Table 1. Relevant parameters of the telephoto lens in Example 1 Table 2 Design values ​​for the telephoto lens in Example 1 In Table 2, the surface numbers "S2~S18" are assigned according to the surface sequence of each lens. "OBJ" represents the object plane of the lens; "STO" represents the position of the aperture stop of the lens and the object side position of the sixth lens. "IMA" represents the image plane of the lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat, with an infinite radius of curvature and an infinite distance; the thickness represents the central axial distance between the current surface and the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air; half-aperture represents the effective ray diameter of the lens.

[0039] Figure 3This is the axial aberration diagram of the telephoto lens proposed in Embodiment 1 of this invention. The vertical direction represents the normalized aperture, with 0 indicating on the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the diagram represent different wavelengths of the system imaging, determined by... Figure 3 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the telephoto lens is well controlled at each wavelength.

[0040] Figure 4 This is a field curvature distortion diagram of the telephoto lens proposed in Embodiment 1 of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, which has no unit; where T represents the meridion and S represents the sagitta; from Figure 4 As can be seen, the lens provided in this embodiment effectively controls the field curvature from light with wavelengths of 436nm to 656nm, meaning that during imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the magnitude of distortion in %; the vertical coordinate represents the normalized image height, which has no unit.

[0041] Example 2 Figure 5 This is a schematic diagram of the telephoto lens proposed in Embodiment 2 of the present invention. Figure 5 As shown, the telephoto lens includes a first lens group and a second lens group arranged sequentially from the object side to the image side along the optical axis. The first lens group includes a convex-concave first lens 201 with positive optical power, a biconcave second lens 202 with negative optical power, and a biconvex third lens 203 with positive optical power. The second lens group includes a fourth lens 204, a fifth lens 205, a sixth lens 206, a seventh lens 207, an eighth lens 208, and a ninth lens 209, as well as a combination 210 of a filter and a flat glass plate. The fourth lens 204 and the fifth lens 205 are cemented together to form a cemented lens, the sixth lens 206 and the seventh lens 207 are cemented together to form a cemented lens, and the eighth lens 208 and the ninth lens 209 are cemented together to form a cemented lens. The fourth lens 204 can be a biconvex lens, the fifth lens 205 can be a concave-convex lens, the sixth lens 206 is a biconvex lens, the seventh lens 207 is a biconcave lens, the eighth lens 208 is a biconvex lens, and the ninth lens 209 is a biconcave lens.

[0042] The relevant parameters of the telephoto lens in Example 2 are shown in Table 3.

[0043] In Example 2, the focal length f of the telephoto lens is 14.17mm, the F# is 1.6, and the angle corresponding to φ9.8mm is 40.83°.

[0044] Table 3. Relevant parameters of the telephoto lens in Example 2 Table 4. Design values ​​for the telephoto lens in Example 2. In Table 4, the surface numbers "S2~S18" are assigned according to the surface sequence of each lens. "OBJ" represents the object plane of the lens; "STO" represents the position of the aperture stop of the lens and the object side position of the sixth lens. "IMA" represents the image plane of the lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat, with an infinite radius of curvature and an infinite distance; the thickness represents the central axial distance between the current surface and the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air; half-aperture represents the effective ray diameter of the lens.

[0045] Figure 6 This is the axial aberration diagram of the telephoto lens proposed in Embodiment 2 of the present invention. The vertical direction represents the normalized aperture, with 0 indicating on the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the diagram represent different wavelengths of the system imaging, determined by... Figure 6 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the telephoto lens is well controlled at each wavelength.

[0046] Figure 7 This is a field curvature distortion diagram of the telephoto lens proposed in Embodiment 2 of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, which has no unit; where T represents the meridion and S represents the sagitta; from Figure 7 As can be seen, the lens provided in this embodiment effectively controls the field curvature from light with wavelengths of 436nm to 656nm, meaning that during imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the magnitude of distortion in %; the vertical coordinate represents the normalized image height, which has no unit.

[0047] Example 3 Figure 8 This is a schematic diagram of the telephoto lens proposed in Embodiment 3 of the present invention. Figure 8As shown, the telephoto lens includes a first lens group and a second lens group arranged sequentially from the object side to the image side along the optical axis. The first lens group includes a convex-concave first lens 301 with positive optical power, a biconcave second lens 302 with negative optical power, and a biconvex third lens 303 with positive optical power. The second lens group includes a fourth lens 304, a fifth lens 305, a sixth lens 306, a seventh lens 307, an eighth lens 308, and a ninth lens 309, as well as a combination of a filter and a flat glass plate 310. Among them, the fourth lens 304, the fifth lens 305, and the sixth lens 306 form a cemented lens, and the seventh lens 307 and the eighth lens 308 form a cemented lens. The fourth lens 304 is a biconvex lens, the fifth lens 305 is a biconcave lens, the sixth lens 306 is a biconvex lens, the seventh lens 307 is a biconvex lens, the eighth lens 308 is a biconcave lens, and the ninth lens 309 is a convex-concave lens.

[0048] The relevant parameters of the telephoto lens in Example 3 are shown in Table 5.

[0049] In Example 3, the focal length f of the telephoto lens is 14.12mm, the F# is 2.0, and the angle corresponding to φ9.8mm is 40.98°.

[0050] Table 5. Relevant parameters of the telephoto lens in Example 3 Table 6 Design values ​​for the telephoto lens in Example 3 In Table 6, the surface numbers "S2~S19" are assigned according to the surface sequence of each lens. "OBJ" represents the object plane of the lens; "STO" represents the aperture stop of the lens; "IMA" represents the image plane of the lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane, where "Infinity" indicates that the surface is flat, the radius of curvature is infinite, and the distance is infinite; the thickness represents the central axial distance between the current surface and the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air; half-aperture represents the effective ray diameter of the lens.

[0051] Figure 9 This is the axial aberration diagram of the telephoto lens proposed in Embodiment 3 of the present invention. The vertical direction represents the normalized aperture, with 0 indicating on the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the diagram represent different wavelengths of the system imaging, determined by... Figure 9It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the telephoto lens is well controlled at each wavelength.

[0052] Figure 10 This is a field curvature distortion diagram of the telephoto lens proposed in Embodiment 3 of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, which has no unit; where T represents the meridion and S represents the sagitta; from Figure 10 As can be seen, the lens provided in this embodiment effectively controls the field curvature from light with wavelengths of 436nm to 656nm, meaning that during imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the magnitude of distortion in %; the vertical coordinate represents the normalized image height, which has no unit.

[0053] Example 4 Figure 11 This is a schematic diagram of the telephoto lens proposed in Embodiment 4 of the present invention. Figure 11 As shown, the telephoto lens includes a first lens group and a second lens group arranged sequentially from the object side to the image side along the optical axis. The first lens group includes a convex-concave first lens 401 with positive optical power, a biconcave second lens 402 with negative optical power, and a biconvex third lens 403 with positive optical power. The second lens group includes a fourth lens 404, a fifth lens 405, a sixth lens 406, a seventh lens 407, an eighth lens 408, and a ninth lens 409, and a filter 410. The fifth lens 405 and the sixth lens 406 form a cemented lens, and the seventh lens 407, the eighth lens 408, and the ninth lens 409 form a cemented lens. Among them, the fourth lens 404 is a biconvex lens, the fifth lens 405 is a biconvex lens, the sixth lens 406 is a biconcave lens, the seventh lens 407 is a biconvex lens, the eighth lens 408 is a concave-convex lens, and the ninth lens 409 is a biconcave lens.

[0054] The relevant parameters of the telephoto lens in Example 4 are shown in Table 7.

[0055] In Example 4, the focal length f of the telephoto lens is 14.24mm, the F# is 1.6, and the angle corresponding to φ9.8mm is 41.22°.

[0056] Table 7. Relevant parameters of the telephoto lens in Example 4 Table 8 Design values ​​for the telephoto lens in Example 4 In Table 8, the surface numbers "S2~S19" are assigned according to the surface sequence of each lens. "OBJ" represents the object plane of the lens; "STO" represents the position of the aperture stop of the lens, and also indicates the position of the object side of the fifth lens. "IMA" represents the image plane of the lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat, with an infinite radius of curvature and an infinite distance; the thickness represents the central axial distance between the current surface and the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air; half-aperture represents the effective ray diameter of the lens.

[0057] Figure 12 This is the axial aberration diagram of the telephoto lens proposed in Embodiment 4 of the present invention. The vertical direction represents the normalized aperture, with 0 indicating on the optical axis, and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the diagram represent different wavelengths of the system imaging, determined by... Figure 12 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the telephoto lens is well controlled at each wavelength.

[0058] Figure 13 This is a field curvature distortion diagram of the telephoto lens proposed in Embodiment 4 of the present invention. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in mm; the vertical coordinate represents the normalized image height, which has no unit; where T represents the meridion and S represents the sagitta; from Figure 13 As can be seen, the lens provided in this embodiment effectively controls the field curvature from light with wavelengths of 436nm to 656nm, meaning that during imaging, the difference between the image quality at the center and the image quality at the periphery is small; in the coordinate system on the right, the horizontal coordinate represents the magnitude of distortion in %; the vertical coordinate represents the normalized image height, which has no unit.

[0059] In summary, the telephoto lens proposed in this embodiment of the invention includes: a first lens group and a second lens group arranged sequentially along the optical axis from the object side to the image side. The first lens group includes a convex-concave first lens with positive optical power, a biconcave second lens with negative optical power, and a third lens with positive optical power. The second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens. The maximum field of view (DFOV) of the telephoto lens, the maximum aperture D1 of the object side of the first lens corresponding to the maximum field of view of the telephoto lens, and the image height H corresponding to the maximum field of view of the telephoto lens satisfy the following condition: (D1*180°) / (H*DFOV)≥2.9. Through the reasonable combination of the lenses, the imaging quality of the telephoto lens is effectively improved, and the telephoto lens has a longer detection distance.

[0060] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A telephoto lens, characterized in that, include: The first lens group and the second lens group are arranged sequentially from the object side to the image side along the optical axis. The first lens group includes a convex-concave first lens with positive optical power, a biconcave second lens with negative optical power, and a third lens with positive optical power, arranged sequentially from the object side to the image side. The second lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens, arranged sequentially from the object side to the image side. The telephoto lens has nine lenses with optical power. The fourth lens has negative optical power, the fifth lens has positive optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power. The maximum field of view (DFOV) of the telephoto lens, the maximum aperture (D1) of the object side of the first lens corresponding to the maximum field of view of the telephoto lens, and the image height (H) corresponding to the maximum field of view of the telephoto lens satisfy the following condition: 2.9 ≤ (D1 × 180°) / (H × DFOV) ≤ 3.

18. Alternatively, the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power. The maximum field of view (DFOV) of the telephoto lens, the maximum aperture (D1) of the object side of the first lens corresponding to the maximum field of view of the telephoto lens, and the image height (H) corresponding to the maximum field of view of the telephoto lens satisfy the following condition: 2.9 ≤ (D1 × 180°) / (H × DFOV) ≤ 3.

99. Alternatively, the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has positive optical power, the eighth lens has negative optical power, and the ninth lens has positive optical power. The maximum field of view (DFOV) of the telephoto lens, the maximum aperture (D1) of the object side of the first lens corresponding to the maximum field of view of the telephoto lens, and the image height (H) corresponding to the maximum field of view of the telephoto lens satisfy the following condition: 2.9 ≤ (D1 × 180°) / (H × DFOV) ≤ (3.545 × 2 × 180°) / (9.8 × 40.98°). Alternatively, the fourth lens has positive optical power, the fifth lens has positive optical power, the sixth lens has negative optical power, the seventh lens has positive optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power. The maximum field of view (DFOV) of the telephoto lens, the maximum aperture (D1) of the object side of the first lens corresponding to the maximum field of view of the telephoto lens, and the image height (H) corresponding to the maximum field of view of the telephoto lens satisfy the following condition: 2.9 ≤ (D1 × 180°) / (H × DFOV) ≤ 4.

00. The optical power Φ1 of the first lens and the optical power Φ of the telephoto lens satisfy 0.19≤Φ1 / Φ≤0.55; the optical power Φ2 of the second lens and the optical power Φ of the telephoto lens satisfy -1.76≤Φ2 / Φ≤-1.35; the optical power Φ3 of the third lens and the optical power Φ of the telephoto lens satisfy 0.41≤Φ3 / Φ≤1.

13.

2. The telephoto lens according to claim 1, characterized in that, When the fourth lens has negative optical power, the fifth lens has positive optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power. or, When the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power. The fourth lens and the fifth lens are cemented together to form a cemented lens, the sixth lens and the seventh lens are cemented together to form a cemented lens, and the eighth lens and the ninth lens are cemented together to form a cemented lens; The fourth lens has a convex object-side surface, the fifth lens has a convex image-side surface, the sixth lens is a biconvex lens, the seventh lens is a biconcave lens, the eighth lens is a biconvex lens, and the ninth lens is a biconcave lens.

3. The telephoto lens according to claim 1, characterized in that, When the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, the seventh lens has positive optical power, the eighth lens has negative optical power, and the ninth lens has positive optical power. The fourth lens, the fifth lens, and the sixth lens form a cemented lens, and the seventh lens and the eighth lens form a cemented lens; The fourth lens is a biconvex lens, the fifth lens is a biconcave lens, the sixth lens is a biconvex lens, the seventh lens is a biconvex lens, the eighth lens is a biconcave lens, and the ninth lens is a convex-concave lens.

4. The telephoto lens according to claim 1, characterized in that, When the fourth lens has positive optical power, the fifth lens has positive optical power, the sixth lens has negative optical power, the seventh lens has positive optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power. The fifth lens and the sixth lens form a cemented lens, and the seventh lens, the eighth lens and the ninth lens form a cemented lens; The fourth lens is a biconvex lens, the fifth lens is a biconvex lens, the sixth lens is a biconcave lens, the seventh lens is a biconvex lens, the eighth lens is a concave-convex lens, and the ninth lens is a biconcave lens.

5. The telephoto lens according to claim 1, characterized in that, The maximum field of view (DFOV) of the telephoto lens, the aperture number (FNO) of the telephoto lens, and the total length (TTL) of the telephoto lens satisfy the following relationship: 0.5° / mm < DFOV / FNO / TTL < 0.7° / mm.

6. The telephoto lens according to claim 1, characterized in that, The refractive index Nd1 of the first lens satisfies 1.72<Nd1<2.05, and the Abbe number Vd1 of the first lens satisfies 25<Vd1<60; the refractive index Nd2 of the second lens satisfies 1.67<Nd2<1.88, and the Abbe number Vd2 of the second lens satisfies 18<Vd2<35; the refractive index Nd3 of the third lens satisfies 1.82<Nd3<2.03, and the Abbe number Vd3 of the third lens satisfies 15<Vd3<43.

7. The telephoto lens according to claim 1, characterized in that, The Abbe number Vd5 of the fifth lens satisfies 38<Vd5<64.

8. The telephoto lens according to claim 1, characterized in that, The refractive index Nd8 of the eighth lens satisfies 1.64<Nd8<2.05; the refractive index Nd9 of the ninth lens satisfies 1.72<Nd9<2.

05.

9. The telephoto lens according to claim 1, characterized in that, All of the first lens to the ninth lens are glass spherical lenses.

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