A zoom lens

Abstract

The embodiment of the present application discloses a zoom lens. The zoom lens comprises a first lens group with negative focal length and a second lens group with positive focal length arranged in sequence along an optical axis from an object side to an image side, the focal length of the zoom lens is changed by changing the position of the first lens group and the second lens group on the optical axis; the first lens group comprises a first lens, a second lens and a third lens arranged in sequence along the optical axis from the object side to the image side; the second lens group comprises a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along the optical axis from the object side to the image side. The zoom lens provided by the embodiment of the present application is a two-group variable focal length lens, so that a high-resolution optical lens with small size and large aperture is realized. The zoom lens uses seven lenses, and realizes a high-performance small-size day-and-night confocal zoom lens with a focal length of 3mm to 6mm under a 1 / 2.7 inch CMOS target surface.

Description

Technical Field

[0001] The present invention relates to lens technology, and more particularly to a zoom lens. Background Technology

[0002] With the continuous development of society and the advancement of science and technology, optical imaging lenses have also experienced rapid development in recent years. They are widely used in various fields such as video conferencing, security monitoring, vehicle monitoring, drone aerial photography, and intelligent transportation. Zoom lenses, which can change the shooting range by varying the focal length without altering the shooting distance, are therefore being used more and more extensively.

[0003] However, zoom lenses currently on the market for security monitoring, drone aerial photography and other fields still have many shortcomings, such as a large number of lenses, low imaging resolution, small imaging area, and large size, so they need to be improved. Summary of the Invention

[0004] This invention provides a zoom lens, specifically a two-element zoom lens, to achieve a compact, large-aperture, high-resolution optical lens. This zoom lens utilizes seven lens elements to achieve a high-performance, compact day / night co-focus zoom lens with a focal length ranging from 3mm to 6mm on a 1 / 2.7-inch CMOS sensor.

[0005] This invention provides a zoom lens, including a first lens group with negative optical power and a second lens group with positive optical power arranged sequentially from the object side to the image side along the optical axis. The focal length of the zoom lens can be changed by changing the positions of the first lens group and the second lens group on the optical axis.

[0006] The first lens group includes a first lens, a second lens, and a third lens arranged sequentially along the optical axis from the object side to the image side;

[0007] The second lens group includes a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object side to the image side;

[0008] The first lens has negative optical power, the second lens has negative optical power, the third lens has positive optical power, the fourth lens has positive optical power, the fifth lens has positive optical power, the sixth lens has negative optical power, and the seventh lens has positive optical power.

[0009] Optionally, the first lens is a convex-concave glass spherical lens, the second lens is a biconcave plastic aspherical lens, the third lens is a convex-concave or biconvex plastic aspherical lens, the fourth lens is a biconvex glass spherical lens, the fifth lens is a biconvex plastic aspherical lens, the sixth lens is a biconcave plastic aspherical lens, and the seventh lens is a biconvex or convex-concave plastic aspherical lens.

[0010] Optionally, the optical power of the first lens to the seventh lens satisfies:

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018] in, and These represent the optical power of the first lens through the seventh lens, respectively. This indicates the optical power of the first lens group. This indicates the optical power of the second lens group.

[0019] Optionally, the refractive index and dispersion coefficient of the third to seventh lenses satisfy:

[0020] 1.497≤n3≤1.710; 17.0≤v3≤20.8;

[0021] 1.400≤n4≤1.730;53.4≤v4≤96.0;

[0022] 1.402≤n5≤1.702;42.1≤v5≤60.0;

[0023] 1.498≤n6≤1.710; 17.0≤v6≤36.7;

[0024] 1.425≤n7≤1.710; 17.0≤v7≤60.0;

[0025] Wherein, n3, n4, n5, n6 and n7 represent the refractive indices of the third lens to the seventh lens in sequence, and v3, v4, v5, v6 and v7 represent the Abbe numbers of the third lens to the seventh lens in sequence.

[0026] Optionally, the displacement G1_L of the first lens group from the wide-angle end to the telephoto end, the displacement G2_L of the second lens group from the wide-angle end to the telephoto end, and the total lens length TTL_W of the zoom lens at the wide-angle end satisfy the following:

[0027] 0.13≤G1_L / TTL_W≤0.25;

[0028] 0.07≤G2_L / TTL_W≤0.19.

[0029] Optionally, the image plane diameter IC of the zoom lens and the focal length F_W of the zoom lens at the wide-angle end satisfy the following:

[0030] F_W / IC≤0.51.

[0031] Optionally, the back focal length BFL_W of the zoom lens at the wide-angle end and the total lens length TTL_W of the zoom lens at the wide-angle end satisfy the following:

[0032] BFL_W / TTL_W≥0.10.

[0033] Optionally, the diameter D1 of the first lens and the total length TTL_W of the zoom lens at the wide-angle end satisfy the following:

[0034] D1 / TTL_W<0.58.

[0035] Optionally, the zoom lens has a higher optical power at the wide-angle end. And the optical power at the telephoto end satisfy:

[0036]

[0037] Optionally, the zoom lens may also include an aperture stop;

[0038] The aperture stop is located between the third lens and the fourth lens.

[0039] The zoom lens provided in this invention includes a first lens group with negative optical power and a second lens group with positive optical power arranged sequentially from the object side to the image side along the optical axis, specifically employing seven lenses. The relatively small number of lenses helps to reduce the lens size. The zoom lens switches between wide-angle and telephoto ends by moving the first and second lens groups along the optical axis, wherein the total effective focal length of the zoom lens continuously zooms within the range of 3mm to 6mm. Through the rational design of the structure of each lens and the optical power matching relationship, the zoom lens achieves a high-performance, compact day / night confocal zoom lens under a 1 / 2.7-inch CMOS sensor. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a zoom lens at the wide-angle end, provided in an embodiment of the present invention.

[0041] Figure 2 for Figure 1 A schematic diagram of the telephoto end of a medium zoom lens;

[0042] Figure 3 This is a spherical aberration curve at the wide-angle end of a zoom lens in this embodiment;

[0043] Figure 4 This is a spherical aberration curve at the telephoto end of a zoom lens in this embodiment;

[0044] Figure 5 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment;

[0045] Figure 6 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment;

[0046] Figure 7 This is a field curvature distortion diagram of a zoom lens at the wide-angle end in this embodiment;

[0047] Figure 8 This is a field curvature distortion diagram at the telephoto end of a zoom lens in this embodiment;

[0048] Figure 9 This is a schematic diagram of another zoom lens wide-angle end provided in an embodiment of the present invention;

[0049] Figure 10 for Figure 9 A schematic diagram of the telephoto end of a medium zoom lens;

[0050] Figure 11 This is a spherical aberration curve at the wide-angle end of a zoom lens in this embodiment;

[0051] Figure 12 This is a spherical aberration curve at the telephoto end of a zoom lens in this embodiment;

[0052] Figure 13 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment;

[0053] Figure 14 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment;

[0054] Figure 15 This is a field curvature distortion diagram of a zoom lens at the wide-angle end in this embodiment;

[0055] Figure 16 This is a field curvature distortion diagram at the telephoto end of a zoom lens in this embodiment;

[0056] Figure 17 This is a schematic diagram of the structure of another zoom lens wide-angle end provided in an embodiment of the present invention;

[0057] Figure 18 for Figure 17 A schematic diagram of the telephoto end of a medium zoom lens;

[0058] Figure 19 This is a spherical aberration curve at the wide-angle end of a zoom lens in this embodiment;

[0059] Figure 20 This is a spherical aberration curve at the telephoto end of a zoom lens in this embodiment;

[0060] Figure 21 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment;

[0061] Figure 22 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment;

[0062] Figure 23 This is a field curvature distortion diagram of a zoom lens at the wide-angle end in this embodiment;

[0063] Figure 24 This is a field curvature distortion diagram at the telephoto end of a zoom lens in this embodiment. Detailed Implementation

[0064] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0065] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "upper" or "lower" of another element, it can be formed not only directly "upper" or "lower" of the other element, but also indirectly "upper" or "lower" of the other element through an intermediate element. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0066] Figure 1 This is a schematic diagram of the structure of a zoom lens at the wide-angle end, provided as an embodiment of the present invention. (Reference) Figure 1The zoom lens provided in this embodiment of the invention includes a first lens group 10 with negative optical power and a second lens group 20 with positive optical power arranged sequentially from the object side to the image side along the optical axis. The focal length of the zoom lens can be changed by changing the position of the first lens group 10 and the second lens group 20 on the optical axis. The first lens group 10 includes a first lens 101, a second lens 102 and a third lens 103 arranged sequentially from the object side to the image side along the optical axis. The second lens group 20 includes a fourth lens 201, a fifth lens 202, a sixth lens 203 and a seventh lens 204 arranged sequentially from the object side to the image side along the optical axis. The first lens 101 has negative optical power, the second lens 102 has negative optical power, the third lens 103 has positive optical power, the fourth lens 201 has positive optical power, the fifth lens 202 has positive optical power, the sixth lens 203 has negative optical power, and the seventh lens 204 has positive optical power.

[0067] It is understandable that optical power is the reciprocal of focal length and characterizes the ability of an optical system to deflect light. The larger the absolute value of optical power, the stronger the ability to bend light; the smaller the absolute value, the weaker the ability to bend light. When optical power is positive, the refraction of light is converging; when optical power is negative, the refraction of light is diverging. In this embodiment, the first lens group 10 and the second lens group 20 can be disposed in a single lens barrel (…). Figure 1 Within (not shown), the movement of the first lens group 10 and the second lens group 20 achieves the change of the lens focal length. By setting the optical power relationship of each lens, the total effective focal length of the zoom lens can be continuously zoomed within the range of 3mm to 6mm.

[0068] Among them, zoom lenses are located at the wide-angle end when the focal length is shortest and at the telephoto end when the focal length is longest. At the wide-angle end and the telephoto end, zoom lenses have different focal lengths and optical powers, as well as different lengths or shapes.

[0069] The technical solution of this embodiment uses the movement of the first and second lens groups along the optical axis to switch the zoom lens between the wide-angle and telephoto ends. The total effective focal length of the zoom lens is continuously zoomed within the range of 3mm to 6mm. By rationally designing the structure of each lens and the optical power matching relationship, the zoom lens achieves a high-performance, compact day and night confocal zoom lens under a 1 / 2.7-inch CMOS sensor. Specifically, it uses 7 lenses, a relatively small number, which helps to reduce the lens size. By rationally matching the various lens groups and the optical power of each lens, aberration balance can be effectively achieved at each focal length, ensuring image clarity at different focal lengths. This results in high image quality within a short overall length limit, reducing cost and weight.

[0070] Optionally, the first lens 101 is a convex-concave glass spherical lens, the second lens 102 is a biconcave plastic aspherical lens, the third lens 103 is a convex-concave or biconvex plastic aspherical lens, the fourth lens 201 is a biconvex glass spherical lens, the fifth lens 202 is a biconvex plastic aspherical lens, the sixth lens 203 is a biconcave plastic aspherical lens, and the seventh lens 204 is a biconvex or convex-concave plastic aspherical lens.

[0071] By setting the second lens 102, third lens 103, fifth lens 202, sixth lens 203, and seventh lens 204 as aspherical lenses, higher-order aberrations can be effectively corrected. Furthermore, since the cost of forming aspherical lenses from plastic is far lower than that from glass, using plastic aspherical lenses can also reduce the cost of zoom lenses.

[0072] The surface profile of an aspherical lens satisfies the formula:

[0073]

[0074] Where Z represents the sag of the aspherical surface, c represents the fundamental curvature at the vertex, k represents the conic section constant, r represents the radial coordinate perpendicular to the optical axis, and a i a is the coefficient of the higher-order term. i r 2i For aspherical surfaces, the term is of higher order.

[0075] Furthermore, glass lenses have a strong ability to deflect light. By setting the first lens 101 and the fourth lens 201 as glass spherical lenses, it is helpful to reduce the number of lenses, thereby reducing the size of the lens.

[0076] At the same time, the two materials, glass and plastic, can compensate for each other, balancing high and low temperatures, which makes the zoom lens have stable performance at high and low temperatures and helps to improve the environmental adaptability of the zoom lens.

[0077] The plastic aspherical lens can be made of various plastics known to those skilled in the art, and the glass spherical lens can be made of various types of glass known to those skilled in the art. This embodiment of the invention does not limit the material used.

[0078] In addition, by reasonably setting the shape of each lens, the optical power requirements of the above embodiments can be met, while ensuring that the entire zoom lens structure is compact and highly integrated.

[0079] Optionally, the optical power of the first lens 101 to the seventh lens 204 satisfies:

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] in, and These represent the optical power of the first lens 101 to the seventh lens 204, respectively. This indicates the optical power of the first lens group 10. This indicates the optical power of the second lens group 20.

[0088] Optionally, the refractive index and dispersion coefficient of the third lens 103 to the seventh lens 204 satisfy the following:

[0089] 1.497≤n3≤1.710; 17.0≤v3≤20.8;

[0090] 1.400≤n4≤1.730;53.4≤v4≤96.0;

[0091] 1.402≤n5≤1.702;42.1≤v5≤60.0;

[0092] 1.498≤n6≤1.710; 17.0≤v6≤36.7;

[0093] 1.425≤n7≤1.710; 17.0≤v7≤60.0;

[0094] Wherein, n3, n4, n5, n6 and n7 represent the refractive indices of the third lens 103 to the seventh lens 204 in sequence, and v3, v4, v5, v6 and v7 represent the Abbe numbers of the third lens 103 to the seventh lens 204 in sequence.

[0095] By comprehensively setting parameters such as the optical power, refractive index, and Abbe number of each lens, the imaging effect of the zoom lens can be improved.

[0096] To ensure the zoom lens has sufficient magnification and sharp focus, optionally, the displacement G1_L of the first lens group 10 from the wide-angle end to the telephoto end, the displacement G2_L of the second lens group 20 from the wide-angle end to the telephoto end, and the total lens length TTL_W of the zoom lens at the wide-angle end satisfy the following:

[0097] 0.13≤G1_L / TTL_W≤0.25;

[0098] 0.07≤G2_L / TTL_W≤0.19.

[0099] To enable zoom lenses to have a larger imaging target surface, ensuring better image quality and sharper images, the image plane diameter IC of the zoom lens can optionally satisfy the following conditions with respect to the focal length F_W at the wide-angle end:

[0100] F_W / IC≤0.51.

[0101] To ensure sufficient mounting space for the imaging sensor, optionally, the back focal length BFL_W of the zoom lens at the wide-angle end and the total lens length TTL_W of the zoom lens at the wide-angle end satisfy the following:

[0102] BFL_W / TTL_W≥0.10.

[0103] To avoid an excessively large aperture for the zoom lens and to meet the installation space requirements of the final product, optionally, the diameter D1 of the first lens 101 and the total length TTL_W of the zoom lens at the wide-angle end satisfy the following:

[0104] D1 / TTL_W<0.58.

[0105] To ensure that zoom lenses can achieve both high image quality and a high zoom ratio, the optical power at the wide-angle end of the zoom lens can be adjusted. And the optical power at the telephoto end satisfy:

[0106]

[0107] Optionally, the zoom lens also includes an aperture stop 30; the aperture stop 30 is located between the third lens 103 and the fourth lens 201. By adding the aperture stop 30, edge light can be blocked, which helps to improve image quality.

[0108] Continue to refer to Figure 1 The zoom lens also includes a flat glass plate 40, which is disposed on the image-side side of the seventh lens 204. By placing a flat glass plate 40 of a certain thickness between the seventh lens 204 and the image plane, it serves a protective function while also filtering out unwanted stray light, thereby improving the image quality of the zoom lens. For example, the flat glass plate 40 can filter out infrared light during the day to improve the image quality of the zoom lens.

[0109] For example, Figure 2 for Figure 1 A schematic diagram of the telephoto end of a medium zoom lens is shown in Table 1. Figure 1 and Figure 2 Specific parameters of the adaptive zoom lens:

[0110] Table 1 Specific parameters of zoom lenses

[0111]

[0112]

[0113] Table 2 is... Figure 1 and Figure 2 The specific design parameters of each lens in the zoom lens are as follows:

[0114] Table 2 Design values ​​of various lens parameters for zoom lenses

[0115]

[0116]

[0117] In this designation, surface number 1 represents the front surface (the surface closer to the object side) of the first lens 101, surface number 2 represents the rear surface (the surface closer to the image side) of the first lens 101, and so on; surface numbers 16 and 17 represent the front and rear surfaces of the lens protective glass, respectively. The radius of curvature indicates the degree of curvature of the lens surface; a positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "Infinite" indicates that the surface is planar and the radius of curvature is infinite. Thickness represents the central axial distance between the current surface and the next surface. The units for radius of curvature and thickness are millimeters. Material (nd) represents the refractive index, i.e., the ability of the material between the current surface and the next surface to deflect light. Material (vd) represents the Abbe number, the dispersion characteristic of the material between the current surface and the next surface.

[0118] Table 3 shows the zoom interval values ​​from Table 2:

[0119] Table 3. One design value for zoom interval.

[0120] Wide-angle end telephoto end Zoom interval 1 5.452 0.680 Zoom interval 2 3.240 6.410

[0121] Table 4 is... Figure 1 and Figure 2 Aspherical surface parameters in medium zoom lenses:

[0122] Table 4. One design value for aspheric coefficient in fixed-focus lenses.

[0123]

[0124]

[0125] Where -4.392853E-03 indicates that the a2 coefficient of surface number 3 is -4.392853 × 10 -3 .

[0126] Figure 3 This is a spherical aberration curve at the wide-angle end of a zoom lens in this embodiment, for reference. Figure 3 The spherical aberration of the zoom lens at different wavelengths (0.850μm, 0.656μm, 0.588μm, 0.546μm, 0.486μm and 0.436nm) is within 0.05mm, which means that the axial aberration of the zoom lens is small. Therefore, it can be seen that the zoom lens provided in this embodiment of the invention can correct aberrations well at the wide-angle end.

[0127] Figure 4 This is a spherical aberration curve at the telephoto end of a zoom lens in this embodiment, for reference. Figure 4 The spherical aberration of the zoom lens at different wavelengths (0.850μm, 0.656μm, 0.588μm, 0.546μm, 0.486μm and 0.436nm) is within 0.1mm, which means that the axial aberration of the zoom lens is small. Therefore, it can be seen that the zoom lens provided in this embodiment of the invention can also correct aberrations well at the telephoto end.

[0128] Figure 5 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment. Figure 6 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment, where the horizontal axis represents the normalized entrance pupil and the vertical axis represents the value of the ray deviating from the principal ray on the image plane.

[0129] Figure 7 This is a field curvature distortion diagram at the wide-angle end of a zoom lens in this embodiment, where the left side represents field curvature and the right side represents distortion. (Reference) Figure 7 In the field curvature diagram, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. Figure 7 As can be seen, the zoom lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is relatively small. In the distortion diagram, the horizontal axis represents the magnitude of distortion as a percentage; the vertical axis represents the normalized image height, which has no unit; from... Figure 7 As can be seen, the zoom lens provided in this embodiment has a distortion of less than 70% at the wide-angle end.

[0130] Figure 8 This is a field curvature distortion diagram at the telephoto end of a zoom lens in this embodiment, where the left side represents field curvature and the right side represents distortion. (Reference) Figure 8 In the field curvature diagram, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. Figure 8As can be seen, the zoom lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is relatively small. In the distortion diagram, the horizontal axis represents the magnitude of distortion as a percentage; the vertical axis represents the normalized image height, which has no unit; from... Figure 8 As can be seen, the zoom lens provided in this embodiment has a distortion of less than 14% at the wide-angle end, and the imaging distortion is small, which meets the requirements for low distortion.

[0131] In summary, by Figures 3-8 It can be seen that the zoom lens provided in the embodiments of the present invention has good imaging capabilities.

[0132] For example, Figure 9 This is a schematic diagram of another zoom lens wide-angle end provided in an embodiment of the present invention. Figure 10 for Figure 9 A schematic diagram of the telephoto end of a medium zoom lens is shown in Table 5. Figure 9 and Figure 10 Specific parameters of the adaptive zoom lens:

[0133] Table 5 Specific parameters of zoom lenses

[0134]

[0135] Table 6 is... Figure 9 and Figure 10 The specific design parameters of each lens in the zoom lens are as follows:

[0136] Table 6 Design values ​​of various lens parameters for zoom lenses

[0137] Face number Surface type radius of curvature thickness Materials (nd) Materials (vd) Half diameter 1 spherical 49.843 0.836 1.750 53.8 5.65 2 spherical 4.085 3.005 3.60 3 aspherical -260.195 0.807 1.511 50.0 3.28 4 aspherical 7.548 0.070 3.09 5 aspherical 9.146 1.286 1.701 19.8 2.95 6 aspherical 38.658 Zoom interval 1 2.96 Aperture flat unlimited -0.380 2.90 8 spherical 7.131 2.630 1.630 63.4 4.37 9 spherical -28.723 0.068 4.37 10 aspherical 5.947 2.457 1.502 60.0 2.90 11 Non-planar -5.825 0.205 2.86 12 aspherical -3.014 0.927 1.678 26.7 2.81 13 aspherical 16.419 0.731 2.50 14 aspherical 3.343 3.000 1.525 56.5 3.18 15 aspherical -37.646 Zoom interval 2 3.36 16 flat unlimited 0.665 1.52 64.2 3.59 17 flat unlimited 0.095 3.62 18 Image unlimited 3.53

[0138] In this designation, surface number 1 represents the front surface (the surface closer to the object side) of the first lens 101, surface number 2 represents the rear surface (the surface closer to the image side) of the first lens 101, and so on; surface numbers 16 and 17 represent the front and rear surfaces of the lens protective glass, respectively. The radius of curvature indicates the degree of curvature of the lens surface; a positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "Infinite" indicates that the surface is planar and the radius of curvature is infinite. Thickness represents the central axial distance between the current surface and the next surface. The units for radius of curvature and thickness are millimeters. Material (nd) represents the refractive index, i.e., the ability of the material between the current surface and the next surface to deflect light. Material (vd) represents the Abbe number, the dispersion characteristic of the material between the current surface and the next surface.

[0139] Table 7 shows the zoom interval values ​​from Table 2:

[0140] Table 7. One design value for zoom interval.

[0141]

[0142]

[0143] Table 8 is... Figure 9 and Figure 10 Aspherical surface parameters in medium zoom lenses:

[0144] Table 8. One design value for aspheric coefficient in fixed-focus lenses.

[0145]

[0146] Where -6.809413E-04 indicates that the a2 coefficient of surface number 3 is -6.809413 × 10 -4 .

[0147] Figure 11 This is a spherical aberration curve at the wide-angle end of a zoom lens in this embodiment, for reference. Figure 11 The spherical aberration of the zoom lens at different wavelengths (0.850μm, 0.656μm, 0.588μm, 0.546μm, 0.486μm and 0.436nm) is within 0.05mm, which means that the axial aberration of the zoom lens is small. Therefore, it can be seen that the zoom lens provided in this embodiment of the invention can correct aberrations well at the wide-angle end.

[0148] Figure 12 This is a spherical aberration curve at the telephoto end of a zoom lens in this embodiment, for reference. Figure 12 The spherical aberration of the zoom lens at different wavelengths (0.850μm, 0.656μm, 0.588μm, 0.546μm, 0.486μm and 0.436nm) is within 0.1mm, which means that the axial aberration of the zoom lens is small. Therefore, it can be seen that the zoom lens provided in this embodiment of the invention can also correct aberrations well at the telephoto end.

[0149] Figure 13 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment. Figure 14 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment, where the horizontal axis represents the normalized entrance pupil and the vertical axis represents the value of the ray deviating from the principal ray on the image plane.

[0150] Figure 15 This is a field curvature distortion diagram at the wide-angle end of a zoom lens in this embodiment, where the left side represents field curvature and the right side represents distortion. (Reference) Figure 15 In the field curvature diagram, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. Figure 15As can be seen, the zoom lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is relatively small. In the distortion diagram, the horizontal axis represents the magnitude of distortion as a percentage; the vertical axis represents the normalized image height, which has no unit; from... Figure 15 As can be seen, the zoom lens provided in this embodiment has a distortion of less than 70% at the wide-angle end.

[0151] Figure 16 This is a field curvature distortion diagram at the telephoto end of a zoom lens in this embodiment, where the left side represents field curvature and the right side represents distortion. (Reference) Figure 16 In the field curvature diagram, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. Figure 16 As can be seen, the zoom lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is relatively small. In the distortion diagram, the horizontal axis represents the magnitude of distortion as a percentage; the vertical axis represents the normalized image height, which has no unit; from... Figure 8 As can be seen, the zoom lens provided in this embodiment has a distortion of less than 16% at the wide-angle end, and the imaging distortion is small, which meets the requirements for low distortion.

[0152] In summary, by Figures 11-16 It can be seen that the zoom lens provided in the embodiments of the present invention has good imaging capabilities.

[0153] For example, Figure 17 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. Figure 18 for Figure 17 A schematic diagram of the telephoto end of a medium zoom lens is shown in Table 9. Figure 17 and Figure 18 Specific parameters of the adaptive zoom lens:

[0154] Table 9 Specific parameters of zoom lenses

[0155]

[0156]

[0157] Table 10 is... Figure 17 and Figure 18 The specific design parameters of each lens in the zoom lens are as follows:

[0158] Table 10 Design values ​​of various lens parameters for zoom lenses

[0159]

[0160]

[0161] In this designation, surface number 1 represents the front surface (the surface closer to the object side) of the first lens 101, surface number 2 represents the rear surface (the surface closer to the image side) of the first lens 101, and so on; surface numbers 16 and 17 represent the front and rear surfaces of the lens protective glass, respectively. The radius of curvature indicates the degree of curvature of the lens surface; a positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "Infinite" indicates that the surface is planar and the radius of curvature is infinite. Thickness represents the central axial distance between the current surface and the next surface. The units for radius of curvature and thickness are millimeters. Material (nd) represents the refractive index, i.e., the ability of the material between the current surface and the next surface to deflect light. Material (vd) represents the Abbe number, the dispersion characteristic of the material between the current surface and the next surface.

[0162] Table 11 shows the zoom interval values ​​from Table 10:

[0163] Table 10. One design value for zoom interval.

[0164] Wide-angle end telephoto end Zoom interval 1 5.340 0.680 Zoom interval 2 3.840 7.455

[0165] Table 12 is... Figure 17 and Figure 18 Aspherical surface parameters in medium zoom lenses:

[0166] Table 12. One design value for aspheric coefficient in fixed-focus lenses.

[0167]

[0168]

[0169] Where -3.962468E-03 indicates that the a2 coefficient of surface number 3 is -3.962468 × 10 -3 .

[0170] Figure 19 This is a spherical aberration curve at the wide-angle end of a zoom lens in this embodiment, for reference. Figure 19 The spherical aberration of the zoom lens at different wavelengths (0.850μm, 0.656μm, 0.588μm, 0.546μm, 0.486μm and 0.436nm) is within 0.05mm, which means that the axial aberration of the zoom lens is small. Therefore, it can be seen that the zoom lens provided in this embodiment of the invention can correct aberrations well at the wide-angle end.

[0171] Figure 20 This is a spherical aberration curve at the telephoto end of a zoom lens in this embodiment, for reference. Figure 20The spherical aberration of the zoom lens at different wavelengths (0.850μm, 0.656μm, 0.588μm, 0.546μm, 0.486μm and 0.436nm) is within 0.12mm, which means that the axial aberration of the zoom lens is small. Therefore, it can be seen that the zoom lens provided in this embodiment of the invention can also correct aberrations well at the telephoto end.

[0172] Figure 21 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment. Figure 22 This is a ray fan diagram of the telephoto end of a zoom lens in this embodiment, where the horizontal axis represents the normalized entrance pupil and the vertical axis represents the value of the ray deviating from the principal ray on the image plane.

[0173] Figure 23 This is a field curvature distortion diagram at the wide-angle end of a zoom lens in this embodiment, where the left side represents field curvature and the right side represents distortion. (Reference) Figure 23 In the field curvature diagram, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. Figure 23 As can be seen, the zoom lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is relatively small. In the distortion diagram, the horizontal axis represents the magnitude of distortion as a percentage; the vertical axis represents the normalized image height, which has no unit; from... Figure 23 As can be seen, the zoom lens provided in this embodiment has a distortion of less than 70% at the wide-angle end.

[0174] Figure 24 This is a field curvature distortion diagram at the telephoto end of a zoom lens in this embodiment, where the left side represents field curvature and the right side represents distortion. (Reference) Figure 24 In the field curvature diagram, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit; where T represents meridion and S represents arc loss. Figure 24 As can be seen, the zoom lens provided in this embodiment effectively controls field curvature, meaning that during imaging, the difference in image quality between the center and the periphery is relatively small. In the distortion diagram, the horizontal axis represents the magnitude of distortion as a percentage; the vertical axis represents the normalized image height, which has no unit; from... Figure 16 As can be seen, the zoom lens provided in this embodiment has a distortion of less than 16% at the wide-angle end, and the imaging distortion is small, which meets the requirements for low distortion.

[0175] In summary, by Figures 19-24 It can be seen that the zoom lens provided in the embodiments of the present invention has good imaging capabilities.

[0176] 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 has two lens groups with optical power, including a first lens group with negative optical power and a second lens group with positive optical power arranged sequentially from the object side to the image side along the optical axis. The focal length of the zoom lens is changed by changing the position of the first lens group and the second lens group on the optical axis. The first lens group has three lenses with optical power, including a first lens, a second lens, and a third lens arranged sequentially from the object side to the image side along the optical axis; The second lens group has four lenses with optical power, including a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged sequentially from the object side to the image side along the optical axis; The first lens has negative optical power, the second lens has negative optical power, the third lens has positive optical power, the fourth lens has positive optical power, the fifth lens has positive optical power, the sixth lens has negative optical power, and the seventh lens has positive optical power. The optical power of the first lens to the seventh lens satisfies: 0.75≤φ1 / φF≤1.03; 0.25≤φ2 / φF≤0.43; -0.37≤φ3 / φF≤-0.18; 0.53≤φ4 / φZ≤0.71; 0.91≤φ5 / φZ≤1.14; -1.74≤φ6 / φZ≤-1.48; 0.74≤φ7 / φZ≤1.12; Wherein, φ1, φ2, φ3, φ4, φ5, φ6 and φ7 represent the optical power of the first lens to the seventh lens, respectively, φF represents the optical power of the first lens group, and φZ represents the optical power of the second lens group.

2. The zoom lens according to claim 1, characterized in that, The first lens is a convex-concave glass spherical lens, the second lens is a biconcave plastic aspherical lens, the third lens is a convex-concave or biconvex plastic aspherical lens, the fourth lens is a biconvex glass spherical lens, the fifth lens is a biconvex plastic aspherical lens, the sixth lens is a biconcave plastic aspherical lens, and the seventh lens is a biconvex or convex-concave plastic aspherical lens.

3. The zoom lens according to claim 1, characterized in that, The refractive index and dispersion coefficient of the third to seventh lenses satisfy the following: 1.497≤n3≤1.710; 17.0≤v3≤20.8; 1.400≤n4≤1.730； 53.4≤v4≤96.0； 1.402≤n5≤1.702； 42.1≤v5≤60.0； 1.498≤n6≤1.710; 17.0≤v6≤36.7; 1.425≤n7≤1.710; 17.0≤v7≤60.0; Wherein, n3, n4, n5, n6 and n7 represent the refractive indices of the third lens to the seventh lens in sequence, and v3, v4, v5, v6 and v7 represent the Abbe numbers of the third lens to the seventh lens in sequence.

4. The zoom lens according to claim 1, characterized in that, The displacement G1_L of the first lens group from the wide-angle end to the telephoto end, the displacement G2_L of the second lens group from the wide-angle end to the telephoto end, and the total lens length TTL_W of the zoom lens at the wide-angle end satisfy the following: 0.13≤G1_L / TTL_W≤0.25; 0.07≤G2_L / TTL_W≤0.

19.

5. The zoom lens according to claim 1, characterized in that, The image plane diameter IC of the zoom lens and the focal length F_W of the zoom lens at the wide-angle end satisfy the following: F_W / IC≤0.

51.

6. The zoom lens according to claim 1, characterized in that, The back focal length BFL_W of the zoom lens at the wide-angle end and the total lens length TTL_W of the zoom lens at the wide-angle end satisfy the following: BFL_W / TTL_W≥0.

10.

7. The zoom lens according to claim 1, characterized in that, The diameter D1 of the first lens and the total length TTL_W of the zoom lens at the wide-angle end satisfy the following: D1 / TTL_W<0.

58.

8. The zoom lens according to claim 1, characterized in that, The zoom lens satisfies the following conditions: The optical power φW at the wide-angle end and the optical power φT at the telephoto end. 0.48≤φT / φW≤0.

58.

9. The zoom lens according to claim 1, characterized in that, The zoom lens also includes an aperture stop; The aperture stop is located between the third lens and the fourth lens.

Images