A zoom lens

Abstract

The application discloses a zoom lens, which comprises a focusing lens group and a zoom lens group arranged in sequence along an optical axis from an object side to an image side; the focusing lens group and the zoom lens group reciprocate along the optical axis during zooming; the focusing lens group comprises a first lens with negative refractive power, a second lens with negative refractive power and a third lens with positive refractive power arranged in sequence along the optical axis from the object side to the image side; the zoom lens group comprises a fourth lens with positive refractive power, a fifth lens with positive refractive power, a sixth lens with negative refractive power, a seventh lens with negative refractive power, an eighth lens with negative refractive power and a ninth lens with positive refractive power arranged in sequence along the optical axis from the object side to the image side; the first lens, the fifth lens and the sixth lens are glass spherical lenses; the fifth lens and the sixth lens form a double cemented lens; and the second lens, the third lens, the fourth lens, the seventh lens, the eighth lens and the ninth lens are all plastic aspherical lenses. The above technical scheme can meet the requirement of high imaging quality.

Description

Technical Field

[0001] The present invention relates to the field of optical device technology, and in particular to a zoom lens. Background Technology

[0002] With the rapid development of the security market, the application scenarios of security lenses are becoming increasingly complex and diverse. In some application scenarios, security lenses must meet the requirements of both long-range and short-range imaging clarity, as well as the requirement of high-quality imaging day and night. Using zoom lenses as security lenses can simultaneously satisfy the focusing and imaging needs of both long-range and short-range devices.

[0003] However, existing zoom lenses typically require a large number of lenses, and the cost increases as the imaging range expands. This makes it impossible for existing zoom lenses to simultaneously meet the requirements of infrared confocalization and high / low temperature non-defocus while also keeping costs low. Summary of the Invention

[0004] This invention provides a zoom lens that ensures the zoom lens meets the requirements of infrared confocality and non-defocusing at high and low temperatures, while also taking into account the need for low cost.

[0005] This invention provides a zoom lens, which includes a focusing lens group and a zoom lens group arranged sequentially along the optical axis from the object side to the image side; the focusing lens group and the zoom lens group reciprocate along the optical axis during zooming;

[0006] The focusing lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power arranged sequentially along the optical axis from the object side to the image side.

[0007] The zoom lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with negative optical power, an eighth lens with negative optical power, and a ninth lens with positive optical power, arranged sequentially from the object side to the image side along the optical axis.

[0008] Wherein, the first lens, the fifth lens, and the sixth lens are glass spherical lenses; the fifth lens and the sixth lens constitute a cemented doublet lens;

[0009] The second lens, the third lens, the fourth lens, the seventh lens, the eighth lens, and the ninth lens are all plastic aspherical lenses.

[0010] Optionally, the fourth lens is a biconvex lens, the fifth lens is a biconvex lens, and the sixth lens is a meniscus lens.

[0011] Optionally, the refractive index Nd4, dispersion coefficient Vd4, and focal length F4 of the fourth lens satisfy: 1.72≤Nd4≤1.78, 20≤Vd4≤60, 0.22≤F4 / FW≤0.34; where FW is the focal length of the zoom lens at the wide-angle end.

[0012] Optionally, the refractive index Nd5 and dispersion coefficient Vd5 of the fifth lens satisfy: 1.35≤Nd5≤1.50, 90≤Vd5≤98.

[0013] Optionally, the refractive index Nd6 and dispersion coefficient Vd5 of the sixth lens satisfy: 1.50≤Nd6≤1.70, 30≤Vd6≤60.

[0014] Optionally, the optical power Φ56 of the cemented doublet formed by the fifth lens and the sixth lens, the optical power Φ7 of the seventh lens, the optical power Φ8 of the eighth lens, the optical power Φ9 of the ninth lens, and the optical power ΦW of the zoom lens at the wide-angle end satisfy: 0.2≤(Φ56+Φ7+Φ8+Φ9) / ΦW≤0.4.

[0015] Optionally, the focal length FW of the zoom lens at the wide-angle end and the focal length FT of the zoom lens at the telephoto end satisfy: 1.72≤FT / FW≤1.78.

[0016] Optionally, the interval T1 between the focusing lens group and the zoom lens group, and the total optical system length TTLW of the zoom lens at the wide-angle end, satisfy: 0.14≤T1 / TTLW≤0.2.

[0017] Optionally, the lens with the largest diameter among all lenses in the focusing lens group is the largest lens; the diameter DG1 of the largest lens and the total optical system length TTLW of the zoom lens at the wide-angle end satisfy: 0.35≤DG1 / TTLW≤0.50.

[0018] Optionally, the zoom lens group may also include an aperture stop located in the optical path between the fourth lens and the fifth lens.

[0019] The technical solution of this invention employs a focusing lens group composed of three lenses with optical power and a zoom lens group composed of six lenses with optical power. By rationally allocating the optical power of each lens and making the fifth and sixth lenses form a cemented doublet lens, and by controlling the relative movement of the focusing lens group and the zoom lens group along the optical axis, the focal length of the zoom lens changes from short focal length to long focal length, and the zoom lens can maintain high image quality at the corresponding focal position. At the same time, by setting the first, fifth, and sixth lenses as glass spherical lenses and the second, third, fourth, seventh, eighth, and ninth lenses as plastic spherical lenses, i.e., using a 3G6P lens combination, aberrations can be well corrected, ensuring large aperture, infrared confocality, and no blurring at high and low temperatures. In addition, the lens size can be reduced, and lens costs can be better controlled, resulting in a high cost-performance ratio. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a zoom lens at the wide-angle end according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of a zoom lens at the mid-telephoto end according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of a zoom lens at the telephoto end according to an embodiment of the present invention;

[0023] Figure 4 yes Figure 1 The diagram shows the spherical aberration curve of the zoom lens at the wide-angle end;

[0024] Figure 5 yes Figure 2 The diagram shows the spherical aberration curve of a zoom lens at the mid-telephoto end.

[0025] Figure 6 yes Figure 3 The diagram shows the spherical aberration curve of a zoom lens at the telephoto end.

[0026] Figure 7 yes Figure 1 The diagram shows the chromatic aberration curve of a zoom lens at the wide-angle end.

[0027] Figure 8 yes Figure 2 The diagram shows the chromatic aberration curve of a zoom lens at the mid-range focal length.

[0028] Figure 9 yes Figure 3 The diagram shows the chromatic aberration curve of a zoom lens at the telephoto end.

[0029] Figure 10This is a schematic diagram of another zoom lens at the wide-angle end provided in an embodiment of the present invention;

[0030] Figure 11 This is a schematic diagram of another zoom lens at the mid-telephoto end provided in an embodiment of the present invention;

[0031] Figure 12 This is a schematic diagram of another zoom lens at the telephoto end provided in an embodiment of the present invention;

[0032] Figure 13 yes Figure 10 The diagram shows the spherical aberration curve of the zoom lens at the wide-angle end;

[0033] Figure 14 yes Figure 11 The diagram shows the spherical aberration curve of a zoom lens at the mid-telephoto end.

[0034] Figure 15 yes Figure 12 The diagram shows the spherical aberration curve of a zoom lens at the telephoto end.

[0035] Figure 16 yes Figure 10 The diagram shows the chromatic aberration curve of a zoom lens at the wide-angle end.

[0036] Figure 17 yes Figure 11 The diagram shows the chromatic aberration curve of a zoom lens at the mid-range focal length.

[0037] Figure 18 yes Figure 12 The diagram shows the chromatic aberration curve of a zoom lens at the telephoto end.

[0038] Figure 19 This is a schematic diagram of the structure of another zoom lens at the wide-angle end provided in an embodiment of the present invention;

[0039] Figure 20 This is a schematic diagram of the structure of another zoom lens at the mid-telephoto end provided in an embodiment of the present invention;

[0040] Figure 21 This is a schematic diagram of the structure of another zoom lens at the telephoto end provided in an embodiment of the present invention;

[0041] Figure 22 yes Figure 19 The diagram shows the spherical aberration curve of the zoom lens at the wide-angle end;

[0042] Figure 23 yes Figure 20 The diagram shows the spherical aberration curve of a zoom lens at the mid-telephoto end.

[0043] Figure 24 yes Figure 21 The diagram shows the spherical aberration curve of a zoom lens at the telephoto end.

[0044] Figure 25 yes Figure 19 The diagram shows the chromatic aberration curve of a zoom lens at the wide-angle end.

[0045] Figure 26 yes Figure 20 The diagram shows the chromatic aberration curve of a zoom lens at the mid-range focal length.

[0046] Figure 27 yes Figure 21 The diagram shows the chromatic aberration curve of the zoom lens at the telephoto end. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be fully described below with reference to the accompanying drawings of the embodiments of this invention through specific implementation methods. Obviously, the described embodiments are only some, not all, embodiments of this invention. Various modifications and variations can be made to this invention without departing from the spirit or scope of this invention, which will be obvious to those skilled in the art. Therefore, this invention is intended to cover modifications and variations of this invention that fall within the scope of the corresponding claims (the claimed technical solutions) and their equivalents.

[0048] Furthermore, the terms "first," "second," and similar terms used in the embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "an," "one," or "the" do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "including" or "comprising" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes. In addition, descriptions of "same" or "equal" in the embodiments of this disclosure do not mean that two objects are completely equal in size or shape; they are allowed to be approximately the same or approximately equal within a certain error range.

[0049] It should be noted that the implementation methods provided in the embodiments of the present invention can be combined with each other without contradiction.

[0050] Figure 1 This is a schematic diagram of the structure of a zoom lens at the wide-angle end according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a zoom lens at the mid-telephoto end according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of a zoom lens at the telephoto end according to an embodiment of the present invention. (Refer to...) Figures 1 to 3 The zoom lens provided in this embodiment of the invention includes a focusing lens group G1 and a zoom lens group G2 arranged sequentially from the object side to the image side along the optical axis; the focusing lens group G1 and the zoom lens group G2 reciprocate along the optical axis during zooming; the focusing lens group G1 includes a first lens 10 with negative optical power, a second lens 20 with negative optical power and a third lens 30 with positive optical power arranged sequentially from the object side to the image side along the optical axis; the zoom lens group G2 includes a fourth lens 40 with positive optical power, a fifth lens 50 with positive optical power, a sixth lens 60 with negative optical power, a seventh lens 70 with negative optical power, an eighth lens 80 with negative optical power and a ninth lens 90 with positive optical power arranged sequentially from the object side to the image side along the optical axis.

[0051] In this embodiment, the focusing lens group G1 and the zoom lens group G2 can be disposed in one lens barrel. Figures 1 to 3 Within the lens barrel (not shown), the focusing lens group G1 and the zoom lens group G2 can reciprocate along the optical axis. As the focusing lens group G1 and the zoom lens group G2 move, the focal length of the zoom lens can continuously change from short focal length to long focal length. Specifically, during the zooming process achieved by moving the focusing lens group G1 and the zoom lens group G2, the short focal length is the shortest focal length, at which point the zoom lens is located at the wide-angle end; the long focal length is the longest focal length, at which point the zoom lens is located at the telephoto end. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical powers, as well as different lengths or shapes.

[0052] As can be understood, optical power equals the difference between the convergence of the image-side beam and the convergence of the object-side beam; it characterizes the ability of an optical system to deflect light. The larger the absolute value of optical power, the stronger the bending ability of light; the smaller the absolute value, the weaker the bending ability. When optical power is positive, the refraction of light is converging; when optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0053] By setting the first lens 10, the second lens 20, and the third lens 30 in the focusing lens group G1 to have negative optical power, the optical power of the focusing lens group G1 is negative, ensuring that light has a larger aperture before entering the zoom lens group G2, thus increasing the aperture of the zoom lens. At the same time, by setting the fourth lens 40, the fifth lens 50, the sixth lens 60, the seventh lens 70, the eighth lens 80, and the ninth lens 90 in the zoom lens group G2 to have positive optical power, the optical power of each lens is reasonably allocated, so that the lenses cooperate with each other to ensure that the zoom lens can have high image quality at all focal lengths within its zoom range.

[0054] Continue to refer to Figures 1 to 3 The first lens 10, the fifth lens 50, and the sixth lens 60 are glass spherical lenses; the second lens 20, the third lens 30, the fourth lens 40, the seventh lens 70, the eighth lens 80, and the ninth lens 90 are all plastic aspherical lenses.

[0055] Among them, spherical lenses are characterized by a constant curvature from the center to the periphery, ensuring a simple lens setup. Simultaneously, glass lenses have a low coefficient of thermal expansion and good stability, giving glass spherical lenses higher thermal stability. This allows zoom lenses to maintain good resolution over a wide temperature range when handling high optical power. Furthermore, glass materials offer a wider range of choices, with relatively free selection of refractive index and Abbe constant, allowing for better control over higher aberrations and chromatic aberration, meeting the needs of complex applications. Aspherical lenses, on the other hand, have a continuously changing curvature from the center to the periphery. Aspherical lenses have superior curvature radius characteristics, improving distortion and astigmatism. Moreover, plastic lenses are significantly less expensive than glass lenses.

[0056] In this embodiment, by including three glass spherical lenses and six plastic aspherical lenses in the zoom lens, the zoom lens can effectively correct aberrations, ensuring large aperture, infrared confocality, and no blurring at high and low temperatures. At the same time, it can reduce the size of the lens and better control the lens cost, resulting in a high cost-performance ratio.

[0057] Based on the above embodiments, optionally, the fifth lens 50 and the sixth lens 60 constitute a cemented doublet lens.

[0058] The cemented joint between the fifth lens 50 and the sixth lens 60 can be understood as the image-side surface of the fifth lens 50 and the object-side surface of the sixth lens 60 being bonded together. By cementing the fifth lens 50 and the sixth lens 60, the air gap between them can be reduced, which helps to reduce the overall optical length of the zoom lens. It also reduces tolerance sensitivity issues such as tilting / eccentricity during lens assembly, simplifies the assembly process in zoom lens manufacturing, and improves equipment efficiency. Simultaneously, the cemented joint reduces light loss caused by inter-lens reflection, improves illumination, and reduces the risk of ghosting. Furthermore, cemented lenses can be used to minimize or eliminate chromatic aberration, thereby improving image quality, reducing light energy reflection loss, and enhancing the sharpness of the lens image. In an optional embodiment, the fifth lens 50 and the sixth lens 60 can be supported by a gasket or bonded with adhesive. This invention does not limit the specific bonding method.

[0059] Optionally, the fourth lens 40 is a biconvex lens, the fifth lens 50 is a biconvex lens, and the sixth lens 60 is a meniscus lens.

[0060] Among them, the fourth lens 40 is a biconvex lens, which can be understood as the object side and image side of the fourth lens 40 being convex near the optical axis; the fifth lens 50 is a biconvex lens, which can be understood as the object side and image side of the fifth lens 50 being convex near the optical axis; and the sixth lens 60 is a meniscus lens, which can be understood as the object side of the sixth lens 60 being concave near the optical axis, and the image side of the sixth lens 60 being convex near the optical axis.

[0061] Furthermore, the first lens 10 is a convex-concave lens, the second lens 20 is a biconcave lens, the third lens 30 is a biconvex lens, a convex-concave lens, or a convex-flat lens, the seventh lens 70 is a concave-convex lens, the eighth lens 80 is a biconcave lens, and the ninth lens 90 is a convex-concave lens. In this embodiment, by reasonably setting the shape of each lens, the requirements for high imaging quality are met while ensuring that the zoom lens has a small size.

[0062] Optionally, the refractive index Nd4, dispersion coefficient Vd4, and focal length F4 of the fourth lens 40 satisfy: 1.72≤Nd4≤1.78, 20≤Vd4≤60, 0.22≤F4 / FW≤0.34; FW is the focal length of the zoom lens at the wide-angle end.

[0063] Optionally, the refractive index Nd5 and dispersion coefficient Vd5 of the fifth lens 50 satisfy: 1.35≤Nd5≤1.50, 90≤Vd5≤98.

[0064] Optionally, the refractive index Nd6 and dispersion coefficient Vd5 of the sixth lens 60 satisfy: 1.50≤Nd6≤1.70, 30≤Vd6≤60.

[0065] Among them, the refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It is mainly used to describe the material's ability to refract light. Different materials have different refractive indices. The dispersion coefficient, also known as the Abbe number, is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion of the medium, the larger the Abbe number.

[0066] In this embodiment, by setting the refractive index Nd4, dispersion coefficient Vd4 and focal length F4 of the fourth lens 40, the refractive index Nd5 and dispersion coefficient Vd5 of the fifth lens 50, and the refractive index Nd6 and dispersion coefficient Vd5 of the sixth lens 60 to satisfy the above relationship, it is beneficial to achieve small size, low cost and high imaging quality of zoom lens.

[0067] Optionally, the optical power Φ56 of the cemented doublet formed by the fifth lens 50 and the sixth lens 60, the optical power Φ7 of the seventh lens 70, the optical power Φ8 of the eighth lens 80, the optical power Φ9 of the ninth lens 90, and the optical power ΦW of the zoom lens at the wide-angle end satisfy: 0.2≤(Φ56+Φ7+Φ8+Φ9) / ΦW≤0.4. Thus, by ensuring that the optical power of each lens from the fifth lens 50 to the ninth lens 90 satisfies the above relationship, it is beneficial to simplify the manufacturing process of each lens, reduce the cost of the zoom lens, and improve the image quality of the zoom lens.

[0068] Optionally, the focal length FW at the wide-angle end and the focal length FT at the telephoto end of the zoom lens satisfy the following condition: 1.72 ≤ FT / FW ≤ 1.78. In this way, by setting the ratio of the focal length FT at the telephoto end to the focal length FW at the wide-angle end of the zoom lens, a large zoom ratio and imaging target area are ensured.

[0069] Optionally, the distance T1 between the focusing lens group G1 and the zoom lens group G2, and the total optical system length TTLW of the zoom lens at the wide-angle end, satisfy: 0.14 ≤ T1 / TTLW ≤ 0.2. Thus, by ensuring that the moving distances of the focusing lens group G1 and the zoom lens group G2 satisfy the above relationship, the moving range of the focusing lens group G1 can be minimized to the greatest extent, thereby significantly reducing the size of the zoom lens.

[0070] Optionally, the lens with the largest diameter among all lenses in the focusing lens group G1 is designated as the largest lens; the diameter DG1 of the largest lens and the total optical system length TTLW of the zoom lens at the wide-angle end satisfy the following condition: 0.35 ≤ DG1 / TTLW ≤ 0.50. This configuration can significantly reduce the size of the zoom lens, making it more compact, while maximizing the field of view and light intake to meet the demands of more demanding conditions.

[0071] Optionally, the zoom lens group G2 is also provided with an aperture stop 100 located in the optical path between the fourth lens 40 and the fifth lens 50.

[0072] The aperture 100, located in the optical path between the fourth lens 40 and the fifth lens 50, can adjust the propagation direction of the light beam, thereby minimizing the front and rear apertures of the zoom lens and improving image quality.

[0073] In summary, the embodiments of the present invention employ a focusing lens group composed of three lenses with optical power and a zoom lens group composed of six lenses with optical power. By rationally allocating the optical power of each lens and making the fifth and sixth lenses form a cemented doublet lens, and by controlling the relative movement of the focusing lens group and the zoom lens group along the optical axis, the focal length of the zoom lens changes from short focal length to long focal length, and the zoom lens can maintain high image quality at the corresponding focal position. Furthermore, by setting the first, fifth, and sixth lenses as glass spherical lenses and the second, third, fourth, seventh, eighth, and ninth lenses as plastic spherical lenses (i.e., using a 3G6P lens combination), and by rationally selecting materials for each lens, aberrations can be effectively corrected, ensuring large aperture, infrared confocality, and no blurring at high and low temperatures. Simultaneously, the lens size can be reduced, and lens costs can be better controlled, resulting in a high cost-performance ratio.

[0074] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the zoom lens applicable to the above-described embodiments.

[0075] In one feasible embodiment, Table 1 details a feasible implementation method. Figures 1 to 3 The specific optical and physical parameters of the zoom lens are shown.

[0076] Table 1. Design of optical physical parameters for a zoom lens.

[0077]

[0078] Table 2 shows the design parameters of each lens in a zoom lens corresponding to Table 1, including surface type, radius of curvature, thickness, and material.

[0079] Table 2. Parameter design of each lens in a zoom lens.

[0080]

[0081] The zoom lens of this embodiment includes a focusing lens group G1 and a zoom lens group G2 arranged sequentially along the optical axis from the object side to the image side. The focusing lens group G1 includes a first lens 10, a second lens 20 and a third lens 30 arranged sequentially along the optical axis from the object side to the image side. The zoom lens group G2 includes a fourth lens 40, an aperture stop 100, a fifth lens 50, a sixth lens 60, a seventh lens 70, an eighth lens 80 and a ninth lens 90 arranged sequentially along the optical axis from the object side to the image side. The surface number is determined by the order of the lenses, where "S1" represents the object side of the first lens 10, "S2" represents the image side of the first lens 10, and so on; "STO" represents the aperture 100 in the zoom 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; "INF" indicates that the surface is flat and the radius of curvature 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 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 space indicating that the current position is air; and the half-aperture is the effective radius of the lens surface, in mm.

[0082] The zoom lens in this embodiment has a focal length F range of 4.38mm-7.66mm, an aperture F# range of 1.4-1.8, a total optical system length TTLW of 38.8mm at the wide-angle end, and an optimal working object distance of infinity.

[0083] Table 3 shows the design values ​​for the zoom interval of a zoom lens corresponding to Table 1.

[0084] Table 3. Zoom interval design values ​​for zoom lenses.

[0085] Wide-angle end telephoto end Focusing interval 2.538 0.532 Zoom interval 1 3.932 -0.200 Zoom interval 2 -3.932 0.200

[0086] In this embodiment, the equation Z for the shape of the aspherical surface of the aspherical lens in the zoom lens can be expressed in any feasible way. For example, Z can satisfy the following formula:

[0087]

[0088] Where r represents the perpendicular distance from the optical axis, Z is the distance vector from the vertex of the aspherical surface at position r along the direction perpendicular to the optical axis; c is the fundamental curvature at the vertex, which is numerically the reciprocal of the radius of curvature; k is the conic section constant; A, B, C, D, E, F and G are the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th and 16th order terms of the aspherical polynomial, respectively.

[0089] For example, Table 4 details the aspherical coefficients of each lens in a zoom lens of this embodiment with a feasible implementation method.

[0090] Table 4. Design values ​​for one aspherical coefficient of each lens in zoom lenses.

[0091]

[0092] Where -1.292327E-03 indicates that the coefficient A of surface number S3 is -1.292327 × 10 -3 .

[0093] In this embodiment, Figure 4 yes Figure 1 The diagram shows the spherical aberration curve of a zoom lens at the wide-angle end. Figure 5 yes Figure 2 The diagram shows the spherical aberration curve of a zoom lens at the mid-telephoto end. Figure 6 yes Figure 3 The diagram shown illustrates the spherical aberration curve of a zoom lens at the telephoto end. Figures 4 to 6 The vertical direction represents the normalized aperture, 0 indicates on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Figures 4 to 6 It can be seen that the axial aberrations at different wavelengths (436nm, 486nm, 546nm, 588nm, 656nm) are all controlled within the range of (-0.12mm, +0.12mm), indicating that the spherical aberration of the zoom lens is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.

[0094] Figure 7 yes Figure 1 The diagram shows the chromatic aberration curve of a zoom lens at the wide-angle end. Figure 8 yes Figure 2 The diagram shows the chromatic aberration curve of a zoom lens at the mid-telephoto end. Figure 9 yes Figure 3 The diagram shown illustrates the chromatic aberration curve of a zoom lens at the telephoto end. Figures 7 to 9The vertical direction represents the image height, in mm; the horizontal direction represents the offset of different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) from the optical axis at the image plane after passing through the lenses of this zoom lens, in micrometers (μm); the dashed lines on both sides of the figure represent the Airy disk. Figures 7 to 9 It can be seen that the offset at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) remains within 20.0μm, indicating that the chromatic aberration of the zoom lens at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) is well controlled, which can meet the application requirements of a wide spectrum.

[0095] In another feasible embodiment, Figure 10 This is a schematic diagram of another zoom lens at the wide-angle end provided in an embodiment of the present invention. Figure 11 This is a schematic diagram of another zoom lens at the mid-telephoto end provided in an embodiment of the present invention. Figure 12 This is a schematic diagram of another zoom lens at the telephoto end provided by an embodiment of the present invention. Table 5 details another feasible implementation. Figures 10 to 12 The specific optical and physical parameters of the zoom lens are shown.

[0096] Table 5. Another optical physical parameter design for zoom lenses

[0097] Scope of protection Example 2 lower limit upper limit FT / FW 1.729 1.72 1.78 F4 / FW 0.3286 0.22 0.34 T1 / TTLW 0.1477 0.14 0.20 DG1 / TTLW 0.4092 0.35 0.50 (Φ56+Φ7+Φ8+Φ9) / ΦW 0.288 0.25 0.35 Nd4 1.59 1.50 1.70 Nd5 1.44 1.35 1.50 Nd6 1.54 1.50 1.70 Vd4 55.90 20.00 60.00 Vd5 95.00 90.00 98.00 Vd6 37.10 30.00 60.00

[0098] Table 6 shows the design parameters of each lens in another zoom lens corresponding to Table 5, including surface type, radius of curvature, thickness, and material.

[0099] Table 6. Another parameter design for each lens in a zoom lens.

[0100]

[0101] The zoom lens of this embodiment includes a focusing lens group G1 and a zoom lens group G2 arranged sequentially along the optical axis from the object side to the image side. The focusing lens group G1 includes a first lens 10, a second lens 20 and a third lens 30 arranged sequentially along the optical axis from the object side to the image side. The zoom lens group G2 includes a fourth lens 40, an aperture stop 100, a fifth lens 50, a sixth lens 60, a seventh lens 70, an eighth lens 80 and a ninth lens 90 arranged sequentially along the optical axis from the object side to the image side. The surface number is determined by the order of the lenses, where "S1" represents the object side of the first lens 10, "S2" represents the image side of the first lens 10, and so on; "STO" represents the aperture 100 in the zoom 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; "INF" indicates that the surface is flat and the radius of curvature 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 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 space indicating that the current position is air; and the half-aperture is the effective radius of the lens surface, in mm.

[0102] The zoom lens in this embodiment has a focal length F range of 4.48mm-7.75mm, an aperture F# range of 1.4-1.8, a total optical system length TTLW of 37.4mm at the wide-angle end, and an optimal working object distance of infinity.

[0103] Table 7 shows the design values ​​for the zoom interval of a zoom lens corresponding to Table 5.

[0104] Table 7. Another zoom interval design value for zoom lenses.

[0105] Wide-angle end telephoto end Focusing interval 2.7 1.8292 Zoom interval 1 2.8078 -1.7347 Zoom interval 2 -2.8078 1.7347

[0106] In this embodiment, the equation Z for the shape of the aspherical surface of the aspherical lens in the zoom lens can be expressed in any feasible way. For example, Z can satisfy the following formula:

[0107]

[0108] Where r represents the perpendicular distance from the optical axis, Z is the distance vector from the vertex of the aspherical surface at position r along the direction perpendicular to the optical axis; c is the fundamental curvature at the vertex, which is numerically the reciprocal of the radius of curvature; k is the conic section constant; A, B, C, D, E, F and G are the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th and 16th order terms of the aspherical polynomial, respectively.

[0109] For example, Table 8 details the aspherical coefficients of each lens in a zoom lens of this embodiment with a feasible implementation.

[0110] Table 8. Design values ​​for another aspherical coefficient of each lens in zoom lenses.

[0111]

[0112] Where -1.270086E-04 indicates that the coefficient A of surface number S3 is -1.270086 × 10 -4 .

[0113] In this embodiment, Figure 13 yes Figure 10 The diagram shows the spherical aberration curve of a zoom lens at the wide-angle end. Figure 14 yes Figure 11 The diagram shows the spherical aberration curve of a zoom lens at the mid-telephoto end. Figure 15 yes Figure 12 The diagram shown illustrates the spherical aberration curve of a zoom lens at the telephoto end. Figures 13 to 15 The vertical direction represents the normalized aperture, 0 indicates on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Figures 13 to 15 It can be seen that the axial aberrations at different wavelengths (436nm, 486nm, 546nm, 588nm, 656nm) are all controlled within the range of (-0.18mm, +0.18mm), indicating that the spherical aberration of the zoom lens is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.

[0114] Figure 16 yes Figure 10 The diagram shows the chromatic aberration curve of a zoom lens at the wide-angle end. Figure 17 yes Figure 11 The diagram shows the chromatic aberration curve of a zoom lens at the mid-telephoto end. Figure 18 yes Figure 12 The diagram shown illustrates the chromatic aberration curve of a zoom lens at the telephoto end. Figures 16 to 18 The vertical direction represents the image height, in mm; the horizontal direction represents the offset of different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) from the optical axis at the image plane after passing through the lenses of this zoom lens, in micrometers (μm); the dashed lines on both sides of the figure represent the Airy disk. Figures 16 to 18It can be seen that the offset at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) remains within 8.0μm, indicating that the chromatic aberration of the zoom lens at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) is well controlled, which can meet the application requirements of a wide spectrum.

[0115] In yet another feasible embodiment, Figure 19 This is a schematic diagram of another zoom lens at the wide-angle end provided in an embodiment of the present invention. Figure 20 This is a schematic diagram of the structure of another zoom lens at the mid-telephoto end provided in an embodiment of the present invention. Figure 21 This is a schematic diagram of another zoom lens at the telephoto end provided by an embodiment of the present invention. Table 9 details another feasible implementation method. Figures 19 to 21 The specific optical and physical parameters of the zoom lens are shown.

[0116] Table 9. Another optical physical parameter design for zoom lenses.

[0117] Scope of protection Example 3 lower limit upper limit FT / FW 1.731 1.72 1.78 F4 / FW 0.3288 0.22 0.34 T1 / TTLW 0.1504 0.14 0.20 DG1 / TTLW 0.4038 0.35 0.50 (Φ56+Φ7+Φ8+Φ9) / ΦW 0.299 0.25 0.35 Nd4 1.59 1.50 1.70 Nd5 1.44 1.35 1.50 Nd6 1.65 1.50 1.70 Vd4 55.90 20.00 60.00 Vd5 95.00 90.00 98.00 Vd6 37.10 30.00 60.00

[0118] Table 10 shows the design parameters of the surface type, radius of curvature, thickness, and material of each lens in another type of zoom lens, corresponding to Table 9.

[0119] Table 10: Another parameter design for each lens in a zoom lens.

[0120]

[0121] The zoom lens of this embodiment includes a focusing lens group G1 and a zoom lens group G2 arranged sequentially along the optical axis from the object side to the image side. The focusing lens group G1 includes a first lens 10, a second lens 20 and a third lens 30 arranged sequentially along the optical axis from the object side to the image side. The zoom lens group G2 includes a fourth lens 40, an aperture stop 100, a fifth lens 50, a sixth lens 60, a seventh lens 70, an eighth lens 80 and a ninth lens 90 arranged sequentially along the optical axis from the object side to the image side. The surface number is determined by the order of the lenses, where "S1" represents the object side of the first lens 10, "S2" represents the image side of the first lens 10, and so on; "STO" represents the aperture 100 in the zoom 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; "INF" indicates that the surface is flat and the radius of curvature 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 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 space indicating that the current position is air; and the half-aperture is the effective radius of the lens surface, in mm.

[0122] The zoom lens in this embodiment has a focal length F range of 4.48mm-7.75mm, an aperture F# range of 1.4-1.8, a total optical system length TTLW of 37.4mm at the wide-angle end, and an optimal working object distance of infinity.

[0123] Table 11 shows the design values ​​for the zoom interval of a zoom lens corresponding to Table 9.

[0124] Table 11 Another zoom interval design value for zoom lenses

[0125] Wide-angle end telephoto end Focusing interval 2.6950 1.8202 Zoom interval 1 2.8278 -1.7247 Zoom interval 2 -2.8278 1.7247

[0126] In this embodiment, the equation Z for the shape of the aspherical surface of the aspherical lens in the zoom lens can be expressed in any feasible way. For example, Z can satisfy the following formula:

[0127]

[0128] Where r represents the perpendicular distance from the optical axis, Z is the distance vector from the vertex of the aspherical surface at position r along the direction perpendicular to the optical axis; c is the fundamental curvature at the vertex, which is numerically the reciprocal of the radius of curvature; k is the conic section constant; A, B, C, D, E, F and G are the coefficients of the 4th, 6th, 8th, 10th, 12th, 14th and 16th order terms of the aspherical polynomial, respectively.

[0129] For example, Table 12 details the aspherical coefficients of each lens in a zoom lens of this embodiment with a feasible implementation method.

[0130] Table 12 Design values ​​for another type of aspherical coefficient for each lens in zoom lenses.

[0131]

[0132] Where -1.236283E-04 indicates that the coefficient A of surface number S3 is -1.236283 × 10 -4 .

[0133] In this embodiment, Figure 22 yes Figure 19 The diagram shows the spherical aberration curve of a zoom lens at the wide-angle end. Figure 23 yes Figure 20 The diagram shows the spherical aberration curve of a zoom lens at the mid-telephoto end. Figure 24 yes Figure 21 The diagram shown illustrates the spherical aberration curve of a zoom lens at the telephoto end. Figures 22 to 24 The vertical direction represents the normalized aperture, 0 indicates on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Figures 22 to 24 It can be seen that the axial aberrations at different wavelengths (436nm, 486nm, 546nm, 588nm, 656nm) are all controlled within the range of (-0.20mm, +0.20mm), indicating that the spherical aberration of the zoom lens is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.

[0134] Figure 25 yes Figure 19 The diagram shows the chromatic aberration curve of a zoom lens at the wide-angle end. Figure 26 yes Figure 20 The diagram shows the chromatic aberration curve of a zoom lens at the mid-telephoto end. Figure 27 yes Figure 21 The diagram shown illustrates the chromatic aberration curve of a zoom lens at the telephoto end. Figures 25 to 27 The vertical direction represents the image height, in mm; the horizontal direction represents the offset of different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) from the optical axis at the image plane after passing through the lenses of this zoom lens, in micrometers (μm); the dashed lines on both sides of the figure represent the Airy disk. Figures 25 to 27It can be seen that the offset at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) remains within 7μm, indicating that the chromatic aberration of the zoom lens at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) is well controlled, which can meet the application requirements of a wide spectrum.

[0135] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A zoom lens, characterized in that, The zoom lens comprises, in order from the object side to the image side along the optical axis, a focusing lens group and a zoom lens group; the focusing lens group and the zoom lens group reciprocate along the optical axis during zooming; The focusing lens group comprises, in order from the object side to the image side along the optical axis, a first lens with negative refractive power, a second lens with negative refractive power, and a third lens with positive refractive power; The zoom lens group comprises, in order from the object side to the image side along the optical axis, a fourth lens with positive refractive power, a fifth lens with positive refractive power, a sixth lens with negative refractive power, a seventh lens with negative refractive power, an eighth lens with negative refractive power, and a ninth lens with positive refractive power; The first lens, the fifth lens, and the sixth lens are glass spherical lenses; the fifth lens and the sixth lens constitute a doublet lens; The second lens, the third lens, the fourth lens, the seventh lens, the eighth lens, and the ninth lens are all plastic aspherical lenses.

2. The zoom lens according to claim 1, characterized by The fourth lens is a biconvex lens, the fifth lens is a biconvex lens, and the sixth lens is a meniscus lens.

3. The zoom lens according to claim 1, characterized by The Abbe number Vd4 of the fourth lens and the focal length F4 of the fourth lens satisfy: 20≤Vd4≤60, 0.22≤F4 / FW≤0.34; wherein FW is the focal length of the zoom lens at the wide-angle end.

4. The zoom lens according to claim 1, characterized by The refractive index Nd5 of the fifth lens and the Abbe number Vd5 of the fifth lens satisfy: 1.35≤Nd5≤1.50, 90≤Vd5≤98.

5. The zoom lens according to claim 1, characterized by The refractive index Nd6 of the sixth lens and the Abbe number Vd5 of the sixth lens satisfy: 1.50≤Nd6≤1.70, 30≤Vd6≤60.

6. The zoom lens according to claim 1, characterized by The power Φ56 of the doublet lens constituted by the fifth lens and the sixth lens, the power Φ7 of the seventh lens, the power Φ8 of the eighth lens, the power Φ9 of the ninth lens, and the power ΦW of the zoom lens at the wide-angle end satisfy: 0.2≤(Φ56+Φ7+Φ8+Φ9) / ΦW≤0.

4.

7. The zoom lens according to claim 1, wherein The focal length FW of the zoom lens at the wide-angle end and the focal length FT of the zoom lens at the telephoto end satisfy: 1.72≤FT / FW≤1.

78.

8. The zoom lens according to claim 1, characterized by The interval T1 between the focusing lens group and the zoom lens group, and the total length TTLW of the optical system of the zoom lens at the wide-angle end satisfy: 0.14≤T1 / TTLW≤0.

2.

9. The zoom lens according to claim 1, characterized by The lens with the largest diameter in the focusing lens group is the largest lens; the diameter DG1 of the largest lens and the total length TTLW of the optical system of the zoom lens at the wide-angle end satisfy: 0.35≤DG1 / TTLW≤0.

50.

10. The zoom lens according to claim 1, characterized by The zoom lens group is further provided with a diaphragm in the optical path between the fourth lens and the fifth lens.

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