Zoom lens

Abstract

The invention discloses a zoom lens. The zoom lens comprises a focusing lens group and a zoom lens group which are sequentially arranged from an object side to an image side along an optical axis; 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 focal power, a second lens with negative focal power and a third lens with positive focal power which are sequentially arranged from the object side to the image side along the optical axis; the zoom lens group comprises a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with negative focal power, an eighth lens with negative focal power and a ninth lens with positive focal power which are sequentially arranged from the object side to the image side along the optical axis; the first lens, the fifth lens and the sixth lens are glass spherical lenses; the fifth lens and the sixth lens form a doublet lens; the second lens, the third lens, the fourth lens, the seventh lens, the eighth lens and the ninth lens are plastic aspheric lenses. According to the technical scheme, the requirement of high imaging quality can be met.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of optical devices, and in particular to a zoom lens. Background Art

[0002] With the rapid development of the security market, the application scenarios of security lenses are becoming more and more complex and diverse. In some application scenarios, security lenses must take into account both the imaging clarity requirements of the far end and the near end, as well as the high-quality imaging requirements of day and night. By using zoom lenses as security lenses, the focus imaging of the far end and the near end can be met at the same time.

[0003] However, existing zoom lenses usually require a large number of lenses and the cost will increase as the imaging range expands, making it impossible for existing zoom lenses to simultaneously meet the requirements of infrared confocality and high and low temperature non-defocusing while taking into account low cost requirements. Summary of the invention

[0004] The present invention provides a zoom lens, which can ensure that the zoom lens meets the requirements of infrared confocality and no false focus at high and low temperatures, while taking into account the requirements of low cost.

[0005] The present invention provides a zoom lens, which comprises a focus lens group and a zoom lens group arranged in sequence from the object side to the image side along an optical axis; the focus lens group and the zoom lens group reciprocate along the optical axis during zooming;

[0006] The focusing lens group comprises a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power, which are arranged in sequence from the object side to the image side along the optical axis;

[0007] The zoom lens group includes a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with negative focal power, an eighth lens with negative focal power and a ninth lens with positive focal power, which are arranged in sequence 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 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, the dispersion coefficient Vd4 and the focal length F4 of the fourth lens satisfy: 1.72≤Nd4≤1.78, 20≤Vd4≤60, 0.22≤F4 / FW≤0.34; wherein FW is the focal length of the zoom lens at the wide-angle end.

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

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

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

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

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

[0017] Optionally, the lens with the largest diameter among the lenses 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 when the zoom lens is at the wide-angle end satisfy: 0.35≤DG1 / TTLW≤0.50.

[0018] Optionally, the zoom lens group is further provided with an aperture stop located in the optical path between the fourth lens and the fifth lens.

[0019] The technical solution of the present invention adopts three lenses with optical power to form a focus lens group, and adopts six lenses with optical power to form a zoom lens group. By reasonably allocating the optical power of each lens, and making the fifth lens and the sixth lens form a double-cemented lens, when the focus lens group and the zoom lens group are controlled to move relative to each other along the optical axis, the focal length of the zoom lens changes from short focus to long focus, and the zoom lens can have high imaging quality at corresponding focal positions; at the same time, by setting the first lens, the fifth lens and the sixth lens as glass spherical lenses, and setting the second lens, the third lens, the fourth lens, the seventh lens, the eighth lens and the ninth lens as plastic spherical lenses, that is, using a 3G6P lens combination, aberrations can be well corrected, large aperture, infrared confocality, and no false focus at high and low temperatures can be ensured, and at the same time, the lens size can be reduced, the lens cost can be better controlled, and the lens has a high cost performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of a zoom lens at a wide-angle end provided by an embodiment of the present invention;

[0021] Figure 2 is a schematic structural diagram of a zoom lens provided by an embodiment of the present invention at a mid-focus end;

[0022] Figure 3 is a schematic structural diagram of a zoom lens at a telephoto end provided by an embodiment of the present invention;

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

[0024] Figure 5 yes Figure 2 The spherical aberration curve diagram of the zoom lens at the mid-focus end is shown;

[0025] Figure 6 yes Figure 3 The spherical aberration curve diagram of the zoom lens at the telephoto end is shown;

[0026] Figure 7 yes Figure 1 The chromatic aberration curve diagram of the zoom lens at the wide-angle end is shown;

[0027] Figure 8 yes Figure 2 The chromatic aberration curve diagram of the zoom lens at the mid-focus end is shown;

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

[0029] Fig.10is a schematic structural diagram of another zoom lens provided by an embodiment of the present invention at a wide-angle end;

[0030] Fig.11 is a schematic structural diagram of another zoom lens provided by an embodiment of the present invention at a mid-focus end;

[0031] Fig.12 is a schematic structural diagram of another zoom lens provided by an embodiment of the present invention at a telephoto end;

[0032] Fig.13 yes Fig.10 The spherical aberration curve diagram of the zoom lens at the wide-angle end is shown;

[0033] Fig.14 yes Fig.11 The spherical aberration curve diagram of the zoom lens at the mid-focus end is shown;

[0034] Fig.15 yes Fig.12 The spherical aberration curve diagram of the zoom lens at the telephoto end is shown;

[0035] Fig.16 yes Fig.10 The chromatic aberration curve diagram of the zoom lens at the wide-angle end is shown;

[0036] Fig.17 yes Fig.11 The chromatic aberration curve diagram of the zoom lens at the mid-focus end is shown;

[0037] Fig.18 yes Fig.12 The chromatic aberration curve diagram of the zoom lens at the telephoto end shown;

[0038] Fig.19 is a schematic structural diagram of another zoom lens provided by an embodiment of the present invention at a wide-angle end;

[0039] Fig. 20 is a schematic structural diagram of another zoom lens provided by an embodiment of the present invention at a mid-focus end;

[0040] Fig.21 is a schematic structural diagram of another zoom lens provided by an embodiment of the present invention at a telephoto end;

[0041] Fig. 22 yes Fig.19 The spherical aberration curve diagram of the zoom lens at the wide-angle end is shown;

[0042] Fig.23 yes Fig. 20 The schematic diagram of the spherical aberration curve of the zoom lens at the mid-focus end is shown;

[0043] Fig.24 yes Fig.21 The spherical aberration curve diagram of the zoom lens at the telephoto end is shown;

[0044] Fig.25 yes Fig.19 The chromatic aberration curve diagram of the zoom lens at the wide-angle end is shown;

[0045] Fig.26 yes Fig. 20 The chromatic aberration curve diagram of the zoom lens at the mid-focus end is shown;

[0046] Fig. 27 yes Fig.21 The diagram shows a chromatic aberration curve of a zoom lens at the telephoto end. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be fully described below in conjunction with the drawings in the embodiments of the present invention through specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Various modifications and changes can be made in the present invention without departing from the spirit or scope of the present invention, which is obvious to those skilled in the art. Therefore, the present invention is intended to cover modifications and changes of the present invention that fall within the scope of the corresponding claims (technical solutions claimed for protection) and their equivalents.

[0048] Moreover, the words "first", "second" and similar words used in the embodiments of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "one" or "the" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. In addition, the descriptions of the same, equal, etc. involved in the embodiments of the present disclosure do not mean that the two objects are completely equal in size and shape, and are allowed to be roughly the same or roughly 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 if there is no contradiction.

[0050] Figure 1 is a schematic structural diagram of a zoom lens at a wide-angle end provided by an embodiment of the present invention, Figure 2 is a schematic structural diagram of a zoom lens provided by an embodiment of the present invention at a mid-focus end, Figure 3 is a schematic diagram of the structure of a zoom lens at the telephoto end provided by an embodiment of the present invention, with reference to Figures 1 to 3 The zoom lens provided by the embodiment of the present invention comprises a focus lens group G1 and a zoom lens group G2 which are sequentially arranged from the object side to the image side along the optical axis; the focus lens group G1 and the zoom lens group G2 move back and forth along the optical axis during zooming; the focus lens group G1 comprises 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 which are sequentially arranged from the object side to the image side along the optical axis; the zoom lens group G2 comprises 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 which are sequentially arranged from the object side to the image side along the optical axis.

[0051] In this embodiment, the focus lens group G1 and the zoom lens group G2 can be arranged in one lens barrel ( Figures 1 to 3 The focus lens group G1 and the zoom lens group G2 are not shown in the figure, and the focus lens group G1 and the zoom lens group G2 can move back and forth along the optical axis in the lens barrel. When the focus lens group G1 and the zoom lens group G2 move, the focal length of the zoom lens can be continuously changed from short focus to long focus. In the process of zooming by moving the focus lens group G1 and the zoom lens group G2, the short focus is when the focal length is the shortest, and the zoom lens is at the wide-angle end at this time, and the long focus is when the focal length is the longest, and the zoom lens is at the long focus end at this time. At the wide-angle end and the long focus end, the zoom lens has different focal lengths and optical powers, and also has different lengths or shapes.

[0052] It can be understood that the focal power is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal power, the stronger the ability to bend light, and the smaller the absolute value of the focal power, the weaker the ability to bend light. When the focal power is a positive number, the refraction of light is convergent; when the focal power is a negative number, the refraction of light is divergent. The focal power can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group).

[0053] By setting the first lens 10 in the focusing lens group G1 to have a negative optical focal power, the second lens 20 to have a negative optical focal power, and the third lens 30 to have a positive optical focal power, the optical focal power of the focusing lens group G1 is made negative, thereby ensuring that the light has a larger aperture before entering the zoom lens group G2, thereby increasing the aperture of the zoom lens; at the same time, the fourth lens 40 in the zoom lens group G2 is set to have a positive optical focal power, the fifth lens 50 is set to have a positive optical focal power, the sixth lens 60 is set to have a negative optical focal power, the seventh lens 70 is set to have a negative optical focal power, the eighth lens 80 is set to have a negative optical focal power, and the ninth lens 90 is set to have a positive optical focal power, so as to reasonably distribute the optical focal power of each lens, so that each lens cooperates with each other, and the zoom lens can have a high imaging quality at each focal length within its zoom range.

[0054] Continue to refer 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, the characteristic of spherical lenses is that they have a constant curvature from the center of the lens to the periphery of the lens, ensuring that the lens setting method is simple; at the same time, glass lenses have a smaller thermal expansion coefficient and good stability, which enables glass spherical lenses to have higher thermal stability. When taking on more optical power, it can ensure that the zoom lens has good resolution in a wider temperature range. In addition, the range of glass materials available is wider, and the refractive index and Abbe constant are relatively free to choose. To a certain extent, the high-level aberrations and chromatic aberrations of the lens can be controlled to meet the use requirements under complex conditions. The characteristic of aspherical lenses is that the curvature changes continuously from the center of the lens to the periphery of the lens. Aspherical lenses have better curvature radius characteristics, and have the advantages of improving distortion aberration and improving astigmatism aberration. In addition, the cost of plastic lenses is much lower than that of glass lenses.

[0056] In this embodiment, by making the zoom lens include 3 glass spherical lenses and 6 plastic aspherical lenses, the zoom lens can be well corrected for aberrations, ensuring large aperture, infrared confocality, and no out-of-focus at high and low temperatures. At the same time, the lens size can be reduced, the lens cost can be better controlled, and it has a high cost-effectiveness.

[0057] Based on the above embodiment, optionally, the fifth lens 50 and the sixth lens 60 form a doublet lens.

[0058] Among them, the bonding arrangement of the fifth lens 50 and the sixth lens 60 can be understood as the bonding arrangement of the image side surface of the fifth lens 50 and the object side surface of the sixth lens 60. By setting the bonding arrangement of the fifth lens 50 and the sixth lens 60, the air gap between the fifth lens 50 and the sixth lens 60 can be reduced, which helps to reduce the total optical length of the zoom lens, and can also reduce the tolerance sensitivity problems such as tilt / eccentricity generated by the lens during the assembly process, simplify the assembly procedures in the zoom lens manufacturing process, and improve equipment efficiency; at the same time, the bonding arrangement of the fifth lens 50 and the sixth lens 60 can also reduce the light loss caused by reflection between lenses, improve illumination, and reduce the risk of ghosting; in addition, the bonding lens can be used to minimize or eliminate chromatic aberration, thereby improving image quality, reducing the reflection loss of light energy, and improving the clarity of lens imaging. In an optional embodiment, the fifth lens 50 and the sixth lens 60 can be supported by a gasket, or bonded by glue. The present 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 surface and the image side surface of the fourth lens 40 are both convex surfaces at the near optical axis, the fifth lens 50 is a biconvex lens, which can be understood as the object side surface and the image side surface of the fifth lens 50 are both convex surfaces at the near optical axis, and the sixth lens 60 is a meniscus lens, which can be understood as the object side surface of the sixth lens 60 is concave at the near optical axis, and the image side surface of the sixth lens 60 is convex at the near optical axis.

[0061] In addition, the first lens 10 is a convexo-concave lens, the second lens 20 is a biconcave lens, the third lens 30 is a biconvex lens, a convexo-concave lens, or a convex-planar 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 convexo-concave lens. In this embodiment, by reasonably setting the shape of each lens, the zoom lens can meet the requirements of high imaging quality while ensuring that the zoom lens has a small size.

[0062] Optionally, the refractive index Nd4, the dispersion coefficient Vd4 and the 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 the dispersion coefficient Vd5 of the fifth lens 50 satisfy: 1.35≤Nd5≤1.50, 90≤Vd5≤98.

[0064] Optionally, the refractive index Nd6 and the 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 is also called the Abbe number, which is an index used to represent the dispersion ability of a transparent medium. The more severe the medium dispersion, the smaller the Abbe number; conversely, the milder the medium dispersion, 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 can be beneficial to the small size, low cost and high imaging quality of the zoom lens.

[0067] Optionally, the focal power Φ56 of the doublet lens formed by the fifth lens 50 and the sixth lens 60, the focal power Φ7 of the seventh lens 70, the focal power Φ8 of the eighth lens 80, the focal power Φ9 of the ninth lens 90, and the focal power ΦW of the zoom lens at the wide-angle end satisfy: 0.2≤(Φ56+Φ7+Φ8+Φ9) / ΦW≤0.4. In this way, by making the focal power of each lens from the fifth lens 50 to the ninth lens 90 satisfy the above relationship, it is helpful to simplify the processing method of each lens, reduce the cost of the zoom lens, and improve the imaging quality of the zoom lens.

[0068] 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. In this way, by setting the ratio of the focal length FT of the zoom lens at the telephoto end to the focal length FW of the wide-angle end, it is ensured that the zoom lens has a larger zoom ratio and imaging target surface.

[0069] Optionally, the interval T1 between the focus lens group G1 and the zoom lens group G2, and the total length TTLW of the optical system when the zoom lens is at the wide-angle end satisfy: 0.14≤T1 / TTLW≤0.2. In this way, by making the moving distances of the focus lens group G1 and the zoom lens group G2 satisfy the above relationship, the moving range of the focus lens group G1 can be reduced to the greatest extent, thereby greatly reducing the volume of the zoom lens.

[0070] Optionally, the lens with the largest diameter among the lenses in the focus lens group G1 is the largest lens; the diameter DG1 of the largest lens and the total length TTLW of the optical system when the zoom lens is at the wide-angle end satisfy: 0.35≤DG1 / TTLW≤0.50. This arrangement can greatly reduce the size of the zoom lens, making the zoom lens more compact, while maximizing the field of view and light intake of the zoom lens to meet the use requirements under more stringent conditions.

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

[0072] The aperture 100 disposed in the optical path between the fourth lens 40 and the fifth lens 50 can adjust the propagation direction of the light beam, so as to minimize the front and rear apertures of the zoom lens, which is beneficial to improving the imaging quality.

[0073] In summary, in the embodiment of the present invention, three lenses with optical power are used to form a focus lens group, and six lenses with optical power are used to form a zoom lens group. By reasonably allocating the optical power of each lens, and making the fifth lens and the sixth lens form a double-cemented lens, when the focus lens group and the zoom lens group are controlled to move relative to each other along the optical axis, the focal length of the zoom lens changes from short focus to long focus, and the zoom lens can have a high imaging quality at the corresponding focal position; at the same time, by setting the first lens, the fifth lens and the sixth lens as glass spherical lenses, and setting the second lens, the third lens, the fourth lens, the seventh lens, the eighth lens and the ninth lens as plastic spherical lenses, that is, using a 3G6P lens combination, each lens is reasonably selected, and aberrations can be well corrected to ensure large aperture, infrared confocality, and no false focus at high and low temperatures. At the same time, the lens size can be reduced, the lens cost can be better controlled, and the lens has a high cost performance.

[0074] Specific embodiments of the zoom lens applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0075] In a feasible embodiment, Table 1 describes in detail the following in a feasible implementation manner: Figures 1 to 3 Specific optical physical parameters of the zoom lens are shown.

[0076] Table 1 Optical physical parameter design of zoom lens

[0077]

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

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

[0080]

[0081] The zoom lens of this embodiment includes a focus lens group G1 and a zoom lens group G2 which are arranged in sequence along the optical axis from the object side to the image side. The focus lens group G1 includes a first lens 10, a second lens 20 and a third lens 30 which are arranged in sequence along the optical axis from the object side to the image side. The zoom lens group G2 includes a fourth lens 40, an aperture 100, a fifth lens 50, a sixth lens 60, a seventh lens 70, an eighth lens 80 and a ninth lens 90 which are arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the surface order of each lens, where "S1" represents the object side surface of the first lens 10, "S2" represents the image side surface 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, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents 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 to light, and a blank space represents that the current position is air; the semi-aperture is the effective radius of the lens surface, in mm.

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

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

[0084] Table 3 A zoom interval design value of zoom lens

[0085] Wide angle Telephoto end Focus interval 2.538 0.532 Zoom interval 1 3.932 -0.200 Zoom interval 2 -3.932 0.200

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

[0087]

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

[0089] Exemplarily, Table 4 describes in detail the aspheric coefficients of each lens in a zoom lens of this embodiment in a feasible implementation manner.

[0090] Table 4 Design value of an aspheric coefficient of each lens in the zoom lens

[0091]

[0092] Among them, -1.292327E-03 means that the coefficient A of the surface number S3 is -1.292327×10 -3 .

[0093] In this embodiment, Figure 4 yes Figure 1 The spherical aberration curve diagram of the zoom lens at the wide-angle end is shown in the figure. Figure 5 yes Figure 2 The spherical aberration curve diagram of the zoom lens at the mid-focus end is shown in the figure. Figure 6 yes Figure 3 The schematic diagram of the spherical aberration curve of the zoom lens at the telephoto end is shown in Figures 4 to 6 , the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). Figures 4 to 6 It can be seen that the axial aberrations of 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 at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0094] Figure 7 yes Figure 1 The chromatic aberration curve diagram of the zoom lens at the wide-angle end is shown. Figure 8 yes Figure 2 The chromatic aberration curve diagram of the zoom lens at the mid-focus end is shown in the figure. Fig. 9 yes Figure 3 The chromatic aberration curve diagram of the zoom lens at the telephoto end is shown in FIG. Figures 7 to 9, 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 the zoom lens, in micrometers (μm); the vertical dotted lines on both sides of the figure are Airy disks. Figures 7 to 9 It can be seen that the offset at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) is kept 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 and can meet the application requirements of a wide spectrum.

[0095] In another possible embodiment, Fig.10 is a schematic structural diagram of another zoom lens provided by an embodiment of the present invention at a wide-angle end, Fig.11 is a schematic structural diagram of another zoom lens provided by an embodiment of the present invention at a mid-focus end, Fig.12 is a schematic diagram of the structure of another zoom lens provided by an embodiment of the present invention at the telephoto end. Table 5 describes in detail another feasible implementation manner. Figures 10 to 12 Specific optical physical parameters of the zoom lens are shown.

[0096] Table 5 Another optical physical parameter design of zoom lens

[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 the surface type, curvature radius, thickness, material, etc. of each lens in another zoom lens corresponding to Table 5.

[0099] Table 6 Another parameter design of each lens in the zoom lens

[0100]

[0101] The zoom lens of this embodiment includes a focus lens group G1 and a zoom lens group G2 which are arranged in sequence along the optical axis from the object side to the image side. The focus lens group G1 includes a first lens 10, a second lens 20 and a third lens 30 which are arranged in sequence along the optical axis from the object side to the image side. The zoom lens group G2 includes a fourth lens 40, an aperture 100, a fifth lens 50, a sixth lens 60, a seventh lens 70, an eighth lens 80 and a ninth lens 90 which are arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the surface order of each lens, where "S1" represents the object side surface of the first lens 10, "S2" represents the image side surface 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, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents 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 to light, and a blank space represents that the current position is air; the semi-aperture is the effective radius of the lens surface, in mm.

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

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

[0104] Table 7 Another zoom interval design value of zoom lens

[0105] Wide angle Telephoto end Focus interval 2.7 1.8292 Zoom interval 1 2.8078 -1.7347 Zoom interval 2 -2.8078 1.7347

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

[0107]

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

[0109] Exemplarily, Table 8 describes in detail the aspheric coefficients of each lens in a zoom lens of this embodiment in a feasible implementation manner.

[0110] Table 8 Design values ​​of another aspheric coefficient of each lens in the zoom lens

[0111]

[0112] Among them, -1.270086E-04 means that the coefficient A of the surface number S3 is -1.270086×10 -4 .

[0113] In this embodiment, Fig.13 yes Fig.10 The spherical aberration curve diagram of the zoom lens at the wide-angle end is shown in the figure. Fig.14 yes Fig.11 The spherical aberration curve diagram of the zoom lens at the mid-focus end is shown in the figure. Fig.15 yes Fig.12 The schematic diagram of the spherical aberration curve of the zoom lens at the telephoto end is shown in Figures 13 to 15 , the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). Figures 13 to 15 It can be seen that the axial aberrations of 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 at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0114] Fig.16 yes Fig.10 The chromatic aberration curve diagram of the zoom lens at the wide-angle end is shown. Fig.17 yes Fig.11 The chromatic aberration curve diagram of the zoom lens at the mid-focus end is shown in the figure. Fig.18 yes Fig.12 The chromatic aberration curve diagram of the zoom lens at the telephoto end is shown in FIG. 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 the zoom lens, in micrometers (μm); the vertical dotted lines on both sides of the figure are Airy disks. Figures 16 to 18It can be seen that the offset at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) is maintained 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 and can meet the application requirements of a wide spectrum.

[0115] In another possible embodiment, Fig.19 is a schematic structural diagram of another zoom lens at the wide-angle end provided by an embodiment of the present invention, Fig. 20 is a structural schematic diagram of another zoom lens provided by an embodiment of the present invention at a mid-focus end, Fig.21 is a schematic diagram of the structure of another zoom lens at the telephoto end provided by an embodiment of the present invention. Table 9 describes in detail another feasible implementation manner. Figures 19 to 21 Specific optical physical parameters of the zoom lens are shown.

[0116] Table 9 Another optical physical parameter design of zoom lens

[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, curvature radius, thickness, material, etc. of each lens in another zoom lens corresponding to Table 9.

[0119] Table 10 Another parameter design of each lens in the zoom lens

[0120]

[0121] The zoom lens of this embodiment includes a focus lens group G1 and a zoom lens group G2 which are arranged in sequence along the optical axis from the object side to the image side. The focus lens group G1 includes a first lens 10, a second lens 20 and a third lens 30 which are arranged in sequence along the optical axis from the object side to the image side. The zoom lens group G2 includes a fourth lens 40, an aperture 100, a fifth lens 50, a sixth lens 60, a seventh lens 70, an eighth lens 80 and a ninth lens 90 which are arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the surface order of each lens, where "S1" represents the object side surface of the first lens 10, "S2" represents the image side surface 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, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side, "INF" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface; the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and a blank space represents 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 to light, and a blank space represents that the current position is air; the semi-aperture is the effective radius of the lens surface, in mm.

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

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

[0124] Table 11 Another zoom interval design value of zoom lens

[0125] Wide angle Telephoto end Focus interval 2.6950 1.8202 Zoom interval 1 2.8278 -1.7247 Zoom interval 2 -2.8278 1.7247

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

[0127]

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

[0129] Exemplarily, Table 12 describes in detail the aspheric coefficients of each lens in a zoom lens of this embodiment in a feasible implementation manner.

[0130] Table 12 Design values ​​of another aspheric coefficient of each lens in the zoom lens

[0131]

[0132] Among them, -1.236283E-04 means that the coefficient A of the surface number S3 is -1.236283×10 -4 .

[0133] In this embodiment, Fig. 22 yes Fig.19 The spherical aberration curve diagram of the zoom lens at the wide-angle end is shown in the figure. Fig.23 yes Fig. 20 The spherical aberration curve diagram of the zoom lens at the mid-focus end is shown in the figure. Fig.24 yes Fig.21 The schematic diagram of the spherical aberration curve of the zoom lens at the telephoto end is shown in Figure 22 to Figure 24 , the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). Figure 22 to Figure 24 It can be seen that the axial aberrations of 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 at each wavelength is well controlled and can meet the needs of wide spectrum applications.

[0134] Fig.25 yes Fig.19 The chromatic aberration curve diagram of the zoom lens at the wide-angle end is shown. Fig.26 yes Fig. 20 The chromatic aberration curve diagram of the zoom lens at the mid-focus end is shown in the figure. Fig. 27 yes Fig.21 The chromatic aberration curve diagram of the zoom lens at the telephoto end is shown in FIG. Figure 25 to Figure 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 the zoom lens, in micrometers (μm); the vertical dotted lines on both sides of the figure are Airy disks. Figure 25 to Figure 27It can be seen that the offset at different wavelengths (436.0nm, 486.1nm, 546.0nm, 587.6nm, 656.3nm) is kept 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 and can meet the application requirements of a wide spectrum.

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

Claims

1. A zoom lens, characterized in that: The invention comprises a focus lens group and a zoom lens group which are sequentially arranged from the object side to the image side along the optical axis; the focus lens group and the zoom lens group reciprocate along the optical axis during zooming; The focusing lens group comprises a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power, which are arranged in sequence from the object side to the image side along the optical axis; The zoom lens group includes a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with negative focal power, an eighth lens with negative focal power and a ninth lens with positive focal power, which are arranged in sequence from the object side to the image side along the optical axis; Wherein, 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, wherein: 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, wherein: The refractive index Nd4, the dispersion coefficient Vd4 and the focal length F4 of the fourth lens satisfy: 1.72≤Nd4≤1.78, 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, wherein: The refractive index Nd5 and the dispersion coefficient Vd5 of the fifth lens satisfy: 1.35≤Nd5≤1.50, 90≤Vd5≤98.

5. The zoom lens according to claim 1, wherein: The refractive index Nd6 and the dispersion coefficient Vd5 of the sixth lens satisfy: 1.50≤Nd6≤1.70, 30≤Vd6≤60.

6. The zoom lens according to claim 1, wherein: The optical focal length Φ56 of the doublet lens formed by the fifth lens and the sixth lens, the optical focal length Φ7 of the seventh lens, the optical focal length Φ8 of the eighth lens, the optical focal length Φ9 of the ninth lens, and the optical focal length 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: A focal length FW of the zoom lens at a wide angle end and a focal length FT of the zoom lens at a telephoto end satisfy: 1.72≤FT / FW≤1.

78.

8. The zoom lens according to claim 1, wherein: The interval T1 between the focus 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.

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

50.

10. The zoom lens according to claim 1, wherein: The zoom lens group is also provided with an aperture stop located in the optical path between the fourth lens and the fifth lens.

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