A zoom lens

Abstract

The present invention provides a zoom lens, which relates to the technical field of optical devices, and includes a focus lens group and a zoom lens group arranged in sequence from the object plane to the image plane along an optical axis, wherein the focus lens group and the zoom lens group move along the optical axis during zooming, the focus lens group has a negative optical focal length, and the zoom lens group has a positive optical focal length; the focus lens group includes a first lens, a second lens, and a third lens arranged in sequence from the object plane to the image plane; the zoom lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged in sequence from the object plane to the image plane; the fourth lens, the sixth lens, the eighth lens, and the ninth lens have positive optical focal lengths, and the fifth lens and the seventh lens have negative optical focal lengths. An embodiment of the present invention provides a zoom lens to achieve a zoom lens with a small size, a simple structure, a low cost, a high magnification, and good infrared imaging.

Description

Technical Field

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

[0002] In the security field, zoom lenses have been widely used due to their advantages such as long shooting distance and large shooting angle, but the high cost limits the use of zoom lenses. With the development of technology, high pixels, high magnification, low cost, simple structure, and the ability to take infrared imaging into consideration have become requirements for a new generation of security zoom lenses.

[0003] The advantages of the mainstream two-group ultra-wide-angle zoom lenses on the market are simple structure, low cost, the ability to achieve changes from ultra-wide angle to medium-telephoto, and excellent image quality. The disadvantage is that the magnification ratio is low, generally around three times, and it is increasingly unable to meet market demand. Summary of the invention

[0004] The embodiment of the present invention provides a zoom lens to realize a zoom lens with small size, simple structure, low cost, high magnification and good infrared imaging.

[0005] In a first aspect, an embodiment of the present invention provides a zoom lens, comprising a focus lens group and a zoom lens group arranged in sequence from an object plane to an image plane along an optical axis, wherein the focus lens group and the zoom lens group move along the optical axis during zooming, the focus lens group has a negative optical power, and the zoom lens group has a positive optical power;

[0006] The focusing lens group includes a first lens, a second lens and a third lens arranged in sequence from the object plane to the image plane;

[0007] The zoom lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence from the object plane to the image plane; the fourth lens, the sixth lens, the eighth lens and the ninth lens have positive optical power, and the fifth lens and the seventh lens have negative optical power.

[0008] Optionally, the fourth lens is glued to the fifth lens, and a glued lens formed by gluing the fourth lens and the fifth lens has positive optical power.

[0009] Optionally, a stop is further included, and the stop is arranged on the sixth lens.

[0010] Optionally, the object-side surface of the sixth lens is a convex surface, and the image-side surface of the sixth lens is a convex surface;

[0011] The object side surface and the image side surface of the seventh lens are both concave surfaces;

[0012] The object side surface of the eighth lens is a convex surface, and the image side surface of the eighth lens is a concave surface;

[0013] The object side surface of the ninth lens is a convex surface, and the image side surface of the ninth lens is a concave surface;

[0014] The object side surface is the surface of the lens adjacent to the object plane, and the image side surface is the surface of the lens adjacent to the image plane.

[0015] Optionally, the focal length of the focus lens group is F1, the focal length of the zoom lens group is F2, and the focal length of the zoom lens at the wide-angle end is FW, satisfying: -2.732≤F1 / FW≤-2.456; 2.088≤F2 / FW≤2.913.

[0016] Optionally, the total focal length of the fourth lens, the fifth lens and the sixth lens is F, the focal length of the zoom lens at the telephoto end is FT, and the following conditions are satisfied:

[0017] 0.366≤F / FT≤0.447.

[0018] Optionally, the maximum movable distance of the focus lens group is S1, and the maximum movable distance of the zoom lens group is S2, satisfying:

[0019] 2.978≤S2 / S1≤3.530.

[0020] Optionally, the refractive index of the first lens is nd1, and the Abbe number of the first lens is vd1; the refractive index of the fourth lens is nd4, and the Abbe number of the fourth lens is vd4; the refractive index of the fifth lens is nd5, and the Abbe number of the fifth lens is vd5; satisfying:

[0021] 1.54≤nd1≤1.75;39.1≤vd1≤65.00;

[0022] 1.44≤nd4≤1.46;88.00≤vd4≤95.10;

[0023] 1.65≤nd5≤1.69;25≤vd5≤39.50.

[0024] Optionally, the focal length of the zoom lens at the wide-angle end is FW, and the focal length of the zoom lens at the telephoto end is FT, satisfying:

[0025] 4.5≤FT / FW≤6.0.

[0026] Optionally, the total optical length of the zoom lens at the wide-angle end is TTL, the maximum movable distance of the focus lens group is S1, and the maximum movable distance of the zoom lens group is S2, satisfying:

[0027] 9.69≤TTL / S1≤10.29; 2.92≤TTL / S2≤3.26.

[0028] The zoom lens provided in the embodiment of the present invention adopts a two-component structure and uses 9 lenses. The focal powers of the focus lens group and the zoom lens group are set to adopt a negative-positive combination. The focal power of the focus lens group is negative, and the focal power of the zoom lens group is positive, which ensures that the light can enter the subsequent structure through the focus lens group at a larger angle, thereby ensuring the ultra-wide-angle characteristics of the zoom lens. Furthermore, the fourth lens has a positive focal power, the fifth lens has a negative focal power, the sixth lens has a positive focal power, the seventh lens has a negative focal power, the eighth lens has a positive focal power, and the ninth lens has a positive focal power. The total optical length of the zoom lens is less than 51mm, and the aperture number FNO satisfies 1.52<FNO<4.11 under the 1 / 2.7″ target surface, and the resolution is good in the 436nm~850nm band, thereby realizing a zoom lens with a small size, high magnification, infrared and high and low temperature confocality, which meets the use requirements of clear imaging under the 1 / 2.7″ target surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 1 of the present invention;

[0030] Figure 2 A schematic diagram of the structure of a zoom lens at the telephoto end provided by Embodiment 1 of the present invention;

[0031] Figure 3 A vertical axis chromatic aberration diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end;

[0032] Figure 4 A vertical axis chromatic aberration diagram of the zoom lens provided in the first embodiment of the present invention at the telephoto end;

[0033] Figure 5 A light fan diagram of the zoom lens at the wide-angle end provided in the first embodiment of the present invention;

[0034] Figure 6 A light fan diagram of the zoom lens at the telephoto end provided by the first embodiment of the present invention;

[0035] Figure 7 A schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 2 of the present invention;

[0036] Figure 8 A schematic diagram of the structure of a zoom lens at the telephoto end provided by Embodiment 2 of the present invention;

[0037] Fig. 9 A vertical axis chromatic aberration diagram of the zoom lens provided in the second embodiment of the present invention at the wide-angle end;

[0038] Fig.10 A vertical axis chromatic aberration diagram of the zoom lens at the telephoto end provided by the second embodiment of the present invention;

[0039] Fig.11 A light fan diagram of the zoom lens at the wide-angle end provided in the second embodiment of the present invention;

[0040] Fig.12 A light fan diagram of the zoom lens at the telephoto end provided by the second embodiment of the present invention;

[0041] Fig.13 A schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 3 of the present invention;

[0042] Fig.14 A schematic diagram of the structure of a zoom lens at the telephoto end provided by Embodiment 3 of the present invention;

[0043] Fig.15 A vertical axis chromatic aberration diagram of the zoom lens provided in Embodiment 3 of the present invention at the wide-angle end;

[0044] Fig.16 A vertical axis chromatic aberration diagram of the zoom lens at the telephoto end provided by the third embodiment of the present invention;

[0045] Fig.17 A light fan diagram of the zoom lens at the wide-angle end provided in the third embodiment of the present invention;

[0046] Fig.18 This is a light fan diagram of the zoom lens at the telephoto end provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0048] Embodiment 1

[0049] Figure 1 This is a schematic diagram of the structure of a zoom lens at the wide-angle end provided in Embodiment 1 of the present invention. Figure 2 FIG. 1 is a schematic diagram of a zoom lens at a telephoto end provided in Embodiment 1 of the present invention, with reference to FIG. Figure 1 and Figure 2The zoom lens includes a focus lens group G1 and a zoom lens group G2 which are arranged in sequence from the object plane to the image plane IMA along the optical axis. The focus lens group G1 and the zoom lens group G2 move along the optical axis when zooming. The focus lens group G1 can move along the optical axis when zooming, and the zoom lens group G2 can move along the optical axis when zooming. The focus lens group G1 has negative optical power, and the zoom lens group G2 has positive optical power. The focus lens group G1 includes a first lens L1, a second lens L2, and a third lens L3 which are arranged in sequence from the object plane to the image plane IMA.

[0050] The zoom lens group G2 includes a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a ninth lens L9 arranged in sequence from the object plane to the image plane IMA. The fourth lens L4, the sixth lens L6, the eighth lens L8 and the ninth lens L9 have positive refractive power, and the fifth lens L5 and the seventh lens L7 have negative refractive power.

[0051] The zoom lens provided in the embodiment of the present invention adopts a two-component structure, uses 9 lenses, and sets the focal power of the focus lens group G1 and the zoom lens group G2 in a negative-positive combination. The focal power of the focus lens group G1 is negative, and the focal power of the zoom lens group G2 is positive, which ensures that the light can enter the subsequent structure through the focus lens group G1 at a larger angle, ensuring the ultra-wide-angle characteristics of the zoom lens. Furthermore, the fourth lens L4 has a positive focal power, the fifth lens L5 has a negative focal power, the sixth lens L6 has a positive focal power, the seventh lens L7 has a negative focal power, the eighth lens L8 has a positive focal power, and the ninth lens L9 has a positive focal power. The total optical length of the zoom lens is less than 51mm. At a 1 / 2.7″ target surface, the aperture number FNO satisfies 1.52<FNO<4.11, and the resolution is good in the 436nm~850nm band, thus realizing a zoom lens with small size, high magnification, infrared and high and low temperature confocality, which meets the use requirements of clear imaging at a 1 / 2.7″ target surface.

[0052] For example, reference Figure 1 and Figure 2 , the first lens L1 has negative optical power, the second lens L2 has negative optical power, and the third lens L3 has positive optical power.

[0053] For example, reference Figure 1 and Figure 2 , the focus lens group G1 and the zoom lens group G2 are arranged in a lens barrel ( Figure 1The focus lens group G1 and the zoom lens group G2 can move back and forth along the optical axis in the lens barrel. Moving the focus lens group G1 can focus, and moving the zoom lens group G2 can zoom. By changing the positions of the zoom lens group G2 and the focus lens group G1 on the optical axis, the zoom lens can be switched between the wide-angle end and the telephoto end. Focusing is to change the distance between the lens and the imaging surface IMA so that the image of the object is clear. Zooming refers to the operation of changing the focal length of the zoom lens to obtain different sizes of framing fields and perspectives.

[0054] It can be understood that in the process of zooming by changing the positions of the focus lens group G1 and the zoom lens group G2 on the optical axis, the zoom lens is at the wide-angle end when the focal length is the shortest, and at the telephoto end when the focal length is the longest, the zoom lens has different focal lengths and optical powers at the wide-angle end and the telephoto end. The optical power is inversely proportional to the focal length.

[0055] Focal length is a measure of the convergence or divergence of light in an optical system. It refers to the distance from the optical center of the lens to the focus of light convergence when parallel light is incident. Simply put, the focal length is the distance from the focus to the center point of the mirror. The smaller the absolute value of the focal length, the stronger the ability to bend light, and the larger the absolute value of the optical focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length can be used to characterize a 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).

[0056] Optionally, refer to Figure 1 and Figure 2 , the fourth lens L4 is glued with the fifth lens L5, and the glued lens formed by the glued fourth lens L4 and the fifth lens L5 has positive focal length. The fourth lens L4 and the fifth lens L5 are glued together, so that the chromatic aberration of the incident light at a large angle can be controlled to a certain extent before the aperture STO, and the air gap between the fourth lens L4 and the fifth lens L5 can be reduced, which helps to reduce the total optical length of the zoom lens, and can reduce the light loss caused by reflection between lenses, improve illumination, reduce the risk of ghosting, thereby improving image quality and enhancing the clarity of the zoom lens imaging. Setting the glued lens with positive focal length can balance the temperature refractive index shift caused by other plastic aspherical lenses in the zoom lens, which is beneficial to reduce the resolution degradation caused by temperature drift.

[0057] Optionally, refer to Figure 1 and Figure 2, the zoom lens also includes an aperture STO, which is arranged on the sixth lens L6. That is to say, the edge of the sixth lens L6 is used as the clear aperture of the aperture STO. The light outside the edge of the sixth lens L6 is blocked. Placing the aperture STO on the sixth lens L6 of the zoom lens group G2 can limit the incident angle of light entering the subsequent structure, which can reduce the high-order aberrations in the zoom lens and play a role in improving the image quality. A cemented lens is arranged before the aperture STO, and the cemented lens cooperates with the plastic aspheric lens after the aperture STO, which is conducive to realizing the zoom lens in the full band of 436nm~850nm, high magnification, and high image quality, which can meet the usage requirements in more situations.

[0058] For example, reference Figure 1 and Figure 2 The first lens L1, the fourth lens L4 and the fifth lens L5 are glass spherical lenses, which can improve the stability of the zoom lens and reduce the manufacturing cost.

[0059] For example, reference Figure 1 and Figure 2 , the second lens L2 and the third lens L3 are made of plastic aspherical lenses, which can further reduce the chromatic aberration and other high-order aberrations of the zoom lens. Aberrations are generally divided into two categories: chromatic aberration and monochromatic aberration. Chromatic aberration, referred to as chromatic aberration, is an aberration caused by the refractive index of the lens material being a function of the wavelength. In other embodiments, one of the second lens L2 and the third lens L3 can be made of a plastic aspherical lens, and the other can be made of a glass spherical lens.

[0060] In another embodiment, the second lens L2 and the third lens L3 may be cemented together.

[0061] For example, reference Figure 1 and Figure 2 There is at least one plastic aspherical lens in both the focus lens group G1 and the zoom lens group G2, which can further reduce high-order aberrations such as chromatic aberration of the zoom lens.

[0062] For example, reference Figure 1 and Figure 2 The second lens L2, the third lens L3, the sixth lens L6, the seventh lens L7, the eighth lens L8 and the ninth lens L9 are all plastic aspherical lenses, which can correct high-order aberrations to a greater extent, achieve full-band confocality and high zoom ratio in the 436nm~850nm range, and improve image quality to meet the usage requirements in more situations.

[0063] For example, reference Figure 1 and Figure 2 , the first lens L1, the fourth lens L4 and the fifth lens are glass spherical lenses.

[0064] It should be noted that the aspheric lens in the zoom lens provided in the embodiment of the present invention can be a plastic aspheric lens. In other embodiments, the plastic aspheric lens can be replaced by a glass aspheric lens. The plastic aspheric lens and the glass aspheric lens are collectively referred to as an aspheric lens.

[0065] Among them, glass and plastic can compensate for each other, so as to balance high and low temperatures and reduce the total optical length of the zoom lens, so that the zoom lens has the characteristics of stable high and low temperature performance, improves the environmental adaptability of the zoom lens, and can better correct aberrations. By reasonably matching the temperature coefficient of the glass-plastic hybrid material, the zoom lens can ensure good resolution in high and low temperature environments of -40℃ to 85℃, and can significantly reduce the weight of the zoom lens. In addition, compared with glass lenses, plastic lenses also have obvious cost advantages, which can reduce the cost of zoom lenses.

[0066] The material of the plastic aspheric lens may be various plastics known to those skilled in the art, and the material of the glass spherical lens may be various types of glass known to those skilled in the art, which will not be elaborated or limited in the embodiments of the present invention.

[0067] Optionally, refer to Figure 1 and Figure 2 , the object side surface of the sixth lens L6 is convex, the image side surface of the sixth lens L6 is convex, and the sixth lens L6 is a convex-concave lens. The object side surface and the image side surface of the seventh lens L7 are both concave, and the seventh lens L7 is a double concave lens. The object side surface of the eighth lens L8 is convex, the image side surface of the eighth lens L8 is concave, and the eighth lens L8 is a convex-concave lens. The object side surface of the ninth lens L9 is convex, the image side surface of the ninth lens L9 is concave, and the ninth lens L9 is a convex-concave lens. Among them, the object side surface is the surface of the lens adjacent to the object surface, and the image side surface is the surface of the lens adjacent to the image surface IMA. The embodiment of the present invention limits the curvature direction of each lens surface, realizes the focal length matching of each lens in the above embodiment, realizes a zoom lens with small size, high magnification, low cost, infrared and high and low temperature confocal, and is also beneficial to correcting the chromatic aberration and distortion of the zoom lens, improving the imaging quality, and shortening the total optical length of the zoom lens.

[0068] For example, reference Figure 1 and Figure 2, the object side surface of the first lens L1 is convex, the image side surface of the first lens L1 is concave, and the first lens L1 is a convex-concave lens. The object side surface of the second lens L2 is concave, the image side surface of the second lens L2 is concave, and the second lens L2 is a double concave lens. The object side surface of the third lens L3 is convex, the image side surface of the third lens L3 is convex, and the third lens L3 is a double convex lens. The object side surface of the fourth lens L4 is convex, the image side surface of the fourth lens L4 is convex, and the fourth lens L4 is a double convex lens. The object side surface of the fifth lens L5 is concave, the image side surface of the fifth lens L5 is convex, and the fifth lens L5 is a concave-convex lens.

[0069] For example, reference Figure 1 and Figure 2 , the focal length of the focus lens group G1 is F1, the focal length of the zoom lens group G2 is F2, and the focal length of the zoom lens at the wide-angle end is FW, satisfying: -2.732≤F1 / FW≤-2.456; 2.088≤F2 / FW≤2.913.

[0070] Optionally, refer to Figure 1 and Figure 2 , the total focal length of the fourth lens L4, the fifth lens L5 and the sixth lens L6 is F, the focal length of the zoom lens at the telephoto end is FT, and the following is satisfied: 0.366≤F / FT≤0.447.

[0071] Optionally, refer to Figure 1 and Figure 2 , the maximum movable distance of the focus lens group G1 is S1, and the maximum movable distance of the zoom lens group G2 is S2, which satisfies: 2.978≤S2 / S1≤3.530. By controlling the maximum movable distances of the focus lens group G1 and the zoom lens group G2, the volume of the focus lens group G1 can be reduced, thereby reducing the volume of the zoom lens.

[0072] Optionally, refer to Figure 1 and Figure 2, the refractive index of the first lens L1 is nd1, and the Abbe number of the first lens L1 is vd1. The refractive index of the fourth lens L4 is nd4, and the Abbe number of the fourth lens L4 is vd4. The refractive index of the fifth lens L5 is nd5, and the Abbe number of the fifth lens L5 is vd5. Satisfies: 1.54≤nd1≤1.75, 39.1≤vd1≤65.00. 1.44≤nd4≤1.46, 88.00≤vd4≤95.10. 1.65≤nd5≤1.69, 25≤vd5≤39.50. Among them, the refractive index is the ratio of the propagation speed of light in a vacuum to the propagation 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, and the higher the refractive index of the material, the stronger the ability to refract incident light. The Abbe number is an index used to indicate the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the milder the dispersion of the medium, the larger the Abbe number. In an embodiment of the present invention, setting the first lens L1 as a glass spherical lens with a large refractive index and a high Abbe number can allow the light to have a larger incident aperture before the aperture STO, thereby having greater advantages in correcting spherical aberration and increasing image height. At the same time, the second lens L2 and the third lens L3 use plastic aspherical lenses. The combination of the refractive index and the Abbe number of the second lens L2 and the third lens L3 can better correct the influence of chromatic aberration on subsequent imaging, so that the zoom lens has a higher resolution while reducing the manufacturing cost.

[0073] For example, reference Figure 1 and Figure 2 , the refractive index of the seventh lens L7 is nd7, and the Abbe number of the seventh lens L7 is vd7. The refractive index of the eighth lens L8 is nd8, and the Abbe number of the eighth lens L8 is vd8. The refractive index of the ninth lens L9 is nd9, and the Abbe number of the ninth lens L9 is vd9. By controlling the refractive index and Abbe number of the seventh lens L7, the eighth lens L8 and the ninth lens L9, the maximum light aperture passing through the aperture STO can be controlled to avoid the influence of high-order aberrations. At the same time, with the coordination of the refractive index and Abbe number of the seventh lens L7, the eighth lens L8 and the ninth lens L9, a certain chromatic aberration control effect can be achieved to obtain a wider imaging band range.

[0074] Optionally, refer to Figure 1 and Figure 2 , the focal length of the zoom lens at the wide-angle end is FW, and the focal length of the zoom lens at the telephoto end is FT, which satisfies: 4.5≤FT / FW≤6.0. By controlling the focal length ratio of the zoom lens at the wide-angle end and the telephoto end, the lens can achieve full-band parfocality in the 436nm~850nm range while ensuring that the resolution reaches 4MP, so that the zoom lens has a higher zoom ratio.

[0075] Optionally, refer to Figure 1 and Figure 2 , the total optical length of the zoom lens at the wide-angle end is TTL, the maximum movable distance of the focus lens group G1 is S1, and the maximum movable distance of the zoom lens group G2 is S2, satisfying: 9.69≤TTL / S1≤10.29, 2.92≤TTL / S2≤3.26. The total optical length TTL of the zoom lens at the wide-angle end refers to the distance from the center of the optical axis of the object side of the first lens L1 to the image plane IMA. In an embodiment of the present invention, by limiting the relationship between the focus lens group G1 and the zoom lens group G2 and the total optical length TTL of the zoom lens, the lens space can be compressed to ensure that the size of the zoom lens is small while meeting the requirements of imaging quality and high magnification.

[0076] For example, reference Figure 1 and Figure 2 The zoom lens may further include a flat glass CG, which is located on the side of the ninth lens L9 adjacent to the image plane IMA to protect the photosensitive chip in the imaging sensor. The photosensitive chip is used to convert the light signal collected by the zoom lens into an electrical signal, thereby ensuring the imaging effect of the zoom lens.

[0077] Table 1 A design value of the zoom lens in Example 1

[0078]

[0079]

[0080] Table 1 shows a design value of the zoom lens in the first embodiment, and its specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The zoom lens shown in Table 1 can be Figure 1 and Figure 2As shown in . A lens generally includes two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are numbered according to the surfaces of each lens. Among them, the surface number "1" represents the front surface of the first lens 1 (i.e., the object side), the surface number "2" represents the back surface of the first lens 1 (i.e., the image side), and so on, which will not be repeated here. It should be noted that the radius of curvature represents the degree of curvature of the lens surface. The positive radius of curvature value indicates that the center of curvature is on the side of the surface close to the image plane IMA, that is, the positive value represents that the surface is bent toward the image plane IMA; the negative radius of curvature value represents that the center of curvature is on the side of the surface away from the image plane IMA, that is, the negative value represents that the surface is bent toward the object side. The "INF" in the "Radius of Curvature" column represents that the surface is a plane, and the radius of curvature is infinite, in mm. The value in the "Thickness" column represents the central axial distance from the current surface to the next surface, in mm. The "Refractive Index" column represents the refractive index of the medium between the current surface and the next surface, representing the ability of the material between the current surface and the next surface to deflect light. The blank in the "Refractive Index" column is the refractive index of air, which is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface for light, and the blank represents that the current position is air. The value in the "Half-Aperture" column represents the corresponding half-height of the light on the current surface, in mm.

[0081] Referring to Table 1, the surfaces represented by surface numbers 1 and 2 constitute the first lens L1, the surfaces represented by surface numbers 3 and 4 constitute the second lens L2, the surfaces represented by surface numbers 5 and 6 constitute the third lens L3, the surfaces represented by surface numbers 9 and 10 constitute the fourth lens 4, the surfaces represented by surface numbers 10 and 11 constitute the fifth lens L5, the surfaces represented by surface numbers 13 and 14 constitute the sixth lens L6, the surfaces represented by surface numbers 15 and 16 constitute the seventh lens L7, the surfaces represented by surface numbers 17 and 18 constitute the eighth lens L8, and the surfaces represented by surface numbers 19 and 20 constitute the ninth lens L9. The surfaces represented by surface numbers 22 and 23 constitute the flat glass CG. The surface represented by surface number 24 is the image plane IMA.

[0082] Referring to Table 1, the surfaces represented by surface number 7, surface number 8, surface number 12 and surface number 21 are design reference surfaces, the surface represented by surface number 7 is recorded as the first design reference surface ref1, the surface represented by surface number 8 is recorded as the second design reference surface ref2, and the surface represented by surface number 21 is recorded as the third design reference surface ref3.

[0083] Table 2 Design values ​​of zoom intervals of the zoom lens in Example 1

[0084]

[0085]

[0086] refer to Figure 1 , Figure 2 , Table 1 and Table 2, zoom interval 1 refers to the distance from the image side surface of the third lens L3 (i.e., the surface represented by the surface number 6 in Table 1) to the first design reference surface ref1 (i.e., the surface represented by the surface number 7 in Table 1). Zoom interval 2 refers to the distance from the second design reference surface ref2 (i.e., the surface represented by the surface number 8 in Table 1) to the object side surface of the fourth lens L4 (i.e., the surface represented by the surface number 9 in Table 1). Zoom interval 3 refers to the distance from the image side surface of the ninth lens L9 (i.e., the surface represented by the surface number 20 in Table 1) to the third design reference surface ref3 (i.e., the surface represented by the surface number 21 in Table 1).

[0087] Optionally, the surface of the aspheric lens satisfies the formula:

[0088]

[0089] Among them, z is the axial vector height of the surface in the Z direction, r is the height of the aspheric surface, that is, z is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis; c is the curvature of the fitted sphere, numerically c is the inverse of the radius of curvature, c = 1 / R, R represents the paraxial curvature radius of the mirror; k is the cone coefficient, A, B, C, D, E, F, G, H, I are the aspheric coefficients, specifically, A, B, C, D, E, F, G, H, I are the 4th, 6th, 8th, 10th, 12th, 14th, 16th, 18th and 20th order coefficients of the aspheric polynomial, respectively.

[0090] Table 3 A design value of the aspheric coefficient of the lens in the zoom lens in Example 1

[0091]

[0092]

[0093] Table 3 shows a design value of the aspheric coefficient of the lens in the zoom lens in Example 1. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The ultra-wide-angle lens shown in Table 3 can be Figure 1 and Figure 2 The meaning of the column "surface number" in Table 3 is consistent with that of the column "surface number" in Table 1. "E" in each embodiment of the present invention represents an index with base 10.

[0094] For example, in Embodiment 1, the image plane size of the zoom lens at the wide-angle end is 6.60 mm, and the image plane size at the telephoto end is 6.60 mm. The focal length of the zoom lens at the wide-angle end is 3.6 mm, and the focal length at the telephoto end is 18.03 mm. The distortion of the zoom lens at the wide-angle end is -50.11%, and the distortion at the telephoto end is -1.00%. The zoom lens is suitable for the wavelength band of 436 to 850 nm at the wide-angle end and the telephoto end. The total optical length of the zoom lens at the wide-angle end is 50.7 mm, and the total optical length at the telephoto end is 45.5 mm.

[0095] Figure 3 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the present invention at the wide-angle end is shown in FIG. Figure 4 The vertical axis chromatic aberration curve of the zoom lens provided in the first embodiment of the present invention at the telephoto end is as follows: Figure 3 and Figure 4 As shown, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis represents the maximum pupil radius. The main wavelength uses 546.07nm, and the horizontal direction represents the offset relative to the main wavelength in micrometers (μm). Figure 3 and Figure 4 It can be seen that when the zoom lens is at the wide-angle end, the vertical chromatic aberration of different wavelengths is controlled within the range of (+0.8μm, +10μm); when the zoom lens is at the telephoto end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-0.7μm, +9.2μm), indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is well controlled, which can meet the full-band wide spectrum application requirements.

[0096] Figure 5 This is a light fan diagram of the zoom lens at the wide-angle end provided in the first embodiment of the present invention. Figure 6 The light fan diagram of the zoom lens at the telephoto end provided in the first embodiment of the present invention is one of the evaluation methods commonly used by optical designers. The horizontal axis in the figure is the normalized beam aperture, and the vertical axis is the vertical axis aberration. Ideally, each curve should completely coincide with the horizontal axis, and all light rays in the field of view are focused on the same point on the image plane. The vertical axis in the image can also be expressed as the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberration of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. The maximum scaling ratio in the figure is ±100μm. It can be seen from the figure that this zoom lens is close to the horizontal axis at each wavelength in each field of view, and the infrared defocus is less than 10μm, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, there is no obvious dispersion of the curves of each color, indicating that this zoom lens also has good correction of chromatic aberration, ensuring the imaging requirements of this zoom lens for clear images in the visible light band and infrared band.

[0097] Embodiment 2

[0098] Figure 7 This is a schematic diagram of the structure of the zoom lens at the wide-angle end provided in the second embodiment of the present invention. Figure 8 This is a schematic diagram of the structure of the zoom lens at the telephoto end provided by the second embodiment of the present invention, as shown in FIG. Figure 7 and Figure 8 As shown, the zoom lens provided in the second embodiment of the present invention includes a focus lens group G1, a zoom lens group G2, and an aperture STO arranged in sequence from the object plane to the image plane along the optical axis. The focus lens group G1 is arranged to move along the optical axis, and the zoom lens group G2 is arranged to move in the opposite direction of the optical axis. The focus lens group G1 includes a first lens L1, a second lens L2, and a third lens L3 arranged in sequence from the object plane to the image plane. The zoom lens group G2 includes a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a ninth lens L9 arranged in sequence from the object plane to the image plane. A flat glass CG is also arranged along the object plane to the image plane. The flat glass CG is located on the image side of the ninth lens L9. The flat glass CG can protect the photosensitive chip in the imaging sensor.

[0099] In the zoom lens provided in this embodiment, the focus lens group G1 and the zoom lens group G2 can be arranged in one lens barrel ( Figure 7 and Figure 8 The focus lens group G1 and the zoom lens group G2 can move back and forth along the optical axis in the lens barrel. Through the joint movement of the focus lens group G1 and the zoom lens group G2, the focal length of the zoom lens can be continuously changed from the wide-angle end to the telephoto end, ensuring that the zoom lens has high image quality at each focus position.

[0100] Table 4 describes in detail the specific optical and physical parameters of each lens in the zoom lens provided in Example 2 of the present invention in a feasible implementation manner.

[0101] Table 4 A design value of the zoom lens in Example 2

[0102]

[0103]

[0104] Table 4 shows a design value of the zoom lens in the second embodiment, and its specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The zoom lens shown in Table 4 can be Figure 7 and Figure 8 as shown in .

[0105] Table 5 Zoom interval design values ​​of the zoom lens in Example 2

[0106] Wide angle Telephoto end Zoom interval 1 11.377 6.147 Zoom interval 2 1.212 -14.363 Zoom interval 3 -1.212 14.363

[0107] Table 6 A design value of the aspheric coefficient of the lens in the zoom lens in Example 2

[0108]

[0109]

[0110] Table 6 shows a design value of the aspheric coefficient of the lens in the zoom lens in Example 2. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The ultra-wide-angle lens shown in Table 6 can be Figure 7 and Figure 8 as shown in .

[0111] For example, in Embodiment 2, the image plane size of the zoom lens at the wide-angle end is 6.60 mm, and the image plane size at the telephoto end is 6.60 mm. The focal length of the zoom lens at the wide-angle end is 5.22 mm, and the focal length at the telephoto end is 23.48 mm. The distortion of the zoom lens at the wide-angle end is -30.60%, and the distortion at the telephoto end is -0.35%. The zoom lens is suitable for the wavelength band of 436 to 850 nm at the wide-angle end and the telephoto end. The total optical length of the zoom lens at the wide-angle end is 50.7 mm, and the total optical length at the telephoto end is 45.5 mm.

[0112] Fig. 9 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the present invention at the wide-angle end is shown in FIG. Fig.10 The vertical axis chromatic aberration curve of the zoom lens provided in the second embodiment of the present invention at the telephoto end is as follows: Fig. 9 and Fig.10 As shown, when the zoom lens is at the wide-angle end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-0.4μm, +13μm); when the zoom lens is at the telephoto end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-0.6μm, +1.9μm), indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is well controlled, which can meet the full-band wide spectrum application requirements.

[0113] Fig.11 This is a light fan diagram of the zoom lens at the wide-angle end provided by the second embodiment of the present invention, Fig.12 The light fan diagram of the zoom lens at the telephoto end provided by the second embodiment of the present invention shows that the zoom lens is close to the horizontal axis at each wavelength in each field of view, and the infrared defocus is less than 7.5μm, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously dispersed, indicating that the zoom lens also has good correction for chromatic aberration, ensuring the imaging requirements of the zoom lens for clear images in the visible light band and infrared band.

[0114] Embodiment 3

[0115] The same points as those in the first embodiment are not repeated here. Fig.14 The horizontal lines passing through the lenses indicate the optical axes.

[0116] Table 7 A design value of the zoom lens in Example 3

[0117]

[0118]

[0119] Table 7 shows a design value of the zoom lens in the third embodiment, and its specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The zoom lens shown in Table 7 can be Fig.13 and Fig.14 as shown in .

[0120] Table 8 Zoom interval design values ​​of the zoom lens in Example 3

[0121] Wide-angle end Telephoto end Zoom interval 1 11.910 6.983 Zoom interval 2 1.619 -15.773 Zoom interval 3 -1.619 15.773

[0122] Table 9 A design value of the aspheric coefficient of the lens in the zoom lens in Example 3

[0123]

[0124]

[0125] Table 9 shows a design value of the aspheric coefficient of the lens in the zoom lens in Example 3. The specific value can be adjusted according to product requirements and is not a limitation of the embodiment of the present invention. The ultra-wide-angle lens shown in Table 9 can be Fig.13 and Fig.14 as shown in .

[0126] For example, in Embodiment 3, the image plane size of the zoom lens at the wide-angle end is 6.60 mm, and the image plane size at the telephoto end is 6.60 mm. The focal length of the zoom lens at the wide-angle end is 3.38 mm, and the focal length at the telephoto end is 20.32 mm. The distortion of the zoom lens at the wide-angle end is -76.40%, and the distortion at the telephoto end is -0.90%. The zoom lens is suitable for the wavelength band of 436 to 850 nm at the wide-angle end and the telephoto end. The total optical length of the zoom lens at the wide-angle end is 50.7 mm, and the total optical length at the telephoto end is 45.81 mm.

[0127] Fig.15 This is a vertical axis chromatic aberration curve of the zoom lens provided in the third embodiment of the present invention at the wide-angle end. Fig.16 The vertical axis chromatic aberration curve of the zoom lens at the telephoto end provided by the third embodiment of the present invention is as follows: Fig.15 and Fig.16As shown, when the zoom lens is at the wide-angle end, the vertical chromatic aberration of different wavelengths is controlled within the range of (0.8μm, +14.5μm); when the zoom lens is at the telephoto end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-2.3μm, +7.5μm), indicating that the vertical chromatic aberration of the zoom lens at the wide-angle end and the telephoto end is well controlled, which can meet the full-band wide spectrum application requirements.

[0128] Fig.17 This is a light fan diagram of the zoom lens at the wide-angle end provided in the third embodiment of the present invention. Fig.18 This is a light fan diagram of the zoom lens at the telephoto end provided in the third embodiment of the present invention. It can be seen from the figure that the zoom lens is close to the horizontal axis at each wavelength in each field of view, and the infrared defocus is less than 7.8μm, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, the curves of each color are not obviously dispersed, indicating that the zoom lens also has good correction for chromatic aberration, ensuring the imaging requirements of the zoom lens for clear images in the visible light band and infrared band.

[0129] In order to more clearly illustrate the above embodiments, Table 10 details the specific optical and physical parameters of each lens in the zoom lens provided in Embodiment 1, Embodiment 2 and Embodiment 3 of the present invention.

[0130]

[0131]

[0132] Among them, FNO refers to the aperture number. The other parameters have been introduced and will not be repeated here.

[0133] 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, combinations 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 along the optical axis from the object plane to the image plane, wherein the focus lens group and the zoom lens group move along the optical axis during zooming, the focus lens group has a negative optical power, and the zoom lens group has a positive optical power; The focusing lens group comprises a first lens, a second lens and a third lens arranged in sequence from the object plane to the image plane; the first lens has a negative optical power, the second lens has a negative optical power, and the third lens has a positive optical power; The zoom lens group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence from the object plane to the image plane; the fourth lens, the sixth lens, the eighth lens and the ninth lens have positive optical power, and the fifth lens and the seventh lens have negative optical power; The total focal length of the fourth lens, the fifth lens and the sixth lens is F, the focal length of the zoom lens at the telephoto end is FT, and the following is satisfied: 0.366≤F / FT≤0.447; The optical components with optical power in the zoom lens are only the nine lenses mentioned above.

2. The zoom lens according to claim 1, wherein: The fourth lens is cemented with the fifth lens, and the cemented lens formed by the cementation of the fourth lens and the fifth lens has positive focal power.

3. The zoom lens according to claim 1, wherein: It also includes an aperture, which is arranged on the sixth lens.

4. The zoom lens according to claim 3, wherein: The object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface; The object side surface and the image side surface of the seventh lens are both concave surfaces; The object side surface of the eighth lens is a convex surface, and the image side surface of the eighth lens is a concave surface; The object side surface of the ninth lens is a convex surface, and the image side surface of the ninth lens is a concave surface; The object side surface is the surface of the lens adjacent to the object plane, and the image side surface is the surface of the lens adjacent to the image plane.

5. The zoom lens according to claim 1, wherein: The focal length of the focus lens group is F1, the focal length of the zoom lens group is F2, and the focal length of the zoom lens at the wide-angle end is FW, which satisfies: -2.732≤F1 / FW≤-2.456; 2.088≤F2 / FW≤2.

913.

6. The zoom lens according to claim 1, wherein: The maximum movable distance of the focus lens group is S1, and the maximum movable distance of the zoom lens group is S2, which satisfies: 2.978≤S2 / S1≤3.

530.

7. The zoom lens according to claim 1, wherein: The refractive index of the first lens is nd1, and the Abbe number of the first lens is vd1; the refractive index of the fourth lens is nd4, and the Abbe number of the fourth lens is vd4; the refractive index of the fifth lens is nd5, and the Abbe number of the fifth lens is vd5; satisfying: 1.54≤nd1≤1.75;39.1≤vd1≤65.00; 1.44≤nd4≤1.46;88.00≤vd4≤95.10; 1.65≤nd5≤1.69;25≤vd5≤39.

50.

8. The zoom lens according to claim 1, wherein: The focal length of the zoom lens at the wide-angle end is FW, which satisfies: 4.5≤FT / FW≤6.

0.

9. The zoom lens according to claim 1, wherein: The total optical length of the zoom lens at the wide-angle end is TTL, the maximum movable distance of the focus lens group is S1, and the maximum movable distance of the zoom lens group is S2, satisfying: 9.69≤TTL / S1≤10.29;2.92≤TTL / S2≤3.26。

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