CN221960344U - A zoom lens - Google Patents

Abstract

The embodiment of the utility model discloses a zoom lens, which comprises a negative focal power focusing lens group and a positive focal power zooming lens group which are sequentially arranged from an object plane to an image plane along an optical axis; the focusing lens group comprises a first lens with negative focal power, a second lens with negative focal power and a third lens with positive focal power; the zoom lens group comprises a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, an eighth lens with negative focal power and a ninth lens with positive focal power; setting the total optical length TTL of the zoom lens at the wide angle end, the maximum movable distance S1 of the focusing lens group and the maximum movable distance S2 of the zoom lens group to be more than or equal to 13.88 and less than or equal to TTL/S1 and less than or equal to 55.54; 2.47.ltoreq.TTL-S2 is less than or equal to 3.30. Through rationally setting up the focal power of lens group, the lens quantity that the lens group includes, the focal power of lens and the ratio between the biggest movable concrete of optical total length and different lens groups, guarantee can realize the zoom of simple structure and high variable power.

Description

A zoom lens

Technical Field

The embodiment of the utility model relates to the technical field of optical devices, and in particular to a zoom lens.

Background Art

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.

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.

Utility Model Content

The utility model provides a zoom lens, which realizes the design of a zoom lens with high magnification.

The embodiment of the utility model 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; the optical power of the focus lens group is negative, and the optical power of the zoom lens group is positive;

The focusing lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power;

The zoom lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with negative optical power and a ninth lens with positive optical power;

And, 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30;

Wherein, TTL represents the total optical length of the zoom lens at the wide-angle end, S1 represents the maximum movable distance of the focus lens group, and S2 represents the maximum movable distance of the zoom lens group.

Optional, -2.561≤F1/FW≤-1.041; 2.264≤F2/FW≤3.615;

Among them, F1 represents the focal length of the focus lens group, F2 represents the focal length of the zoom lens group, and FW represents the focal length of the zoom lens at the wide-angle end.

Optional, 4.206≤S2/S1≤22.473;

Among them, S1 represents the maximum movable distance of the focus lens group, and S2 represents the maximum movable distance of the zoom lens group.

Optional, 1.65≤nd1≤1.75; 47.60≤vd1≤60.00; 1.43≤nd4≤1.46; 90.00≤vd4≤96.00;

1.43≤nd7≤1.46; 90.00≤vd71≤96.00; 1.58≤nd8≤1.63; 38.00≤vd8≤47.00;

Among them, nd1 represents the refractive index of the first lens, and vd1 represents the Abbe number of the first lens; nd4 represents the refractive index of the fourth lens, and vd4 represents the Abbe number of the fourth lens; nd7 represents the refractive index of the seventh lens, and vd7 represents the Abbe number of the seventh lens; nd8 represents the refractive index of the eighth lens, and vd8 represents the Abbe number of the eighth lens.

Optionally, 4.5≤FT/FW≤6.0; wherein FT represents the focal length of the zoom lens at the telephoto end, and FW represents the focal length of the zoom lens at the wide-angle end.

Optionally, at least one of the first lens, the fourth lens, the seventh lens and the eighth lens is a glass spherical lens;

The second lens, the third lens, the fifth lens, the sixth lens and the ninth lens are all plastic aspherical lenses.

Optionally, the first lens includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is a convex surface, and the first image-side surface is a concave surface;

The second lens comprises a second object-side surface close to the object plane and a second image-side surface close to the image plane, the second object-side surface is a concave surface, and the second image-side surface is a concave surface;

The third lens comprises a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is a convex surface, and the third image-side surface is a convex surface;

The fourth lens comprises a fourth object-side surface close to the object plane and a fourth image-side surface close to the image plane, the fourth object-side surface is a convex surface, and the fourth image-side surface is a convex surface;

The fifth lens comprises a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane, the fifth object-side surface is a convex surface, and the fifth image-side surface is a concave surface;

The sixth lens comprises a sixth object-side surface close to the object plane and a sixth image-side surface close to the image plane, the sixth object-side surface is a concave surface, and the sixth image-side surface is a convex surface;

The seventh lens comprises a seventh object-side surface close to the object plane and a seventh image-side surface close to the image plane, the seventh object-side surface is a convex surface, and the seventh image-side surface is a convex surface;

The eighth lens comprises an eighth object-side surface close to the object plane and an eighth image-side surface close to the image plane, the eighth object-side surface is a concave surface, and the eighth image-side surface is a concave surface;

The ninth lens includes a ninth object-side surface close to the object plane and a ninth image-side surface close to the image plane. The ninth object-side surface is a convex surface, and the ninth image-side surface is a concave surface.

Optionally, the seventh lens and the eighth lens are bonded together.

Optionally, the zoom lens further includes an aperture stop, and the aperture stop is arranged in the optical path between the third lens and the fourth lens.

Optionally, the zoom lens further includes a filter, and the filter is arranged in the light path between the ninth lens and the image plane.

The zoom lens provided by the embodiment of the utility model is provided by arranging the zoom lens to include a focus lens group with negative optical power and a zoom lens group with positive optical power, and at the same time arranging the focus lens group to include a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power, and arranging the zoom lens group to include a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with negative optical power and a ninth lens with positive optical power; and arranging The total optical length TTL of the zoom lens at the wide-angle end, the maximum movable distance S1 of the focus lens group and the maximum movable distance S2 of the zoom lens group satisfy 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30. By reasonably setting the optical focal length of each lens group, the number of lenses included in each lens group, the optical focal length of each lens and the ratio between the total optical length at the wide-angle end and the maximum movable distance of different lens groups, a zoom lens with a simple structure and a high zoom ratio can be achieved.

It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic structural diagram of a zoom lens at a wide-angle end provided by Embodiment 1 of the present invention;

FIG2 is a schematic structural diagram of a zoom lens at a telephoto end provided by Embodiment 1 of the present invention;

FIG3 is a diagram of vertical axis chromatic aberration of the zoom lens provided in Embodiment 1 of the present invention at the wide-angle end;

FIG4 is a diagram of vertical axis chromatic aberration of the zoom lens provided by the first embodiment of the present invention at the telephoto end;

FIG5 is a diagram showing the field curvature distortion of the zoom lens provided in the first embodiment of the present invention at the wide-angle end;

FIG6 is a diagram showing the field curvature distortion of the zoom lens provided by the first embodiment of the present invention at the telephoto end;

FIG7 is a light fan diagram of the zoom lens provided in the first embodiment of the utility model at the wide-angle end;

FIG8 is a light fan diagram of the zoom lens provided in the first embodiment of the utility model at the telephoto end;

FIG9 is a schematic structural diagram of a zoom lens at a wide-angle end provided by Embodiment 2 of the present invention;

FIG10 is a schematic structural diagram of a zoom lens at a telephoto end provided by Embodiment 2 of the present invention;

FIG11 is a diagram of vertical axis chromatic aberration of the zoom lens provided in Embodiment 2 of the present utility model at the wide-angle end;

FIG12 is a diagram of vertical axis chromatic aberration of the zoom lens provided in Embodiment 2 of the present utility model at the telephoto end;

FIG13 is a diagram showing the field curvature distortion of the zoom lens provided in the second embodiment of the present invention at the wide-angle end;

FIG14 is a diagram showing the field curvature distortion of the zoom lens provided in the second embodiment of the present invention at the telephoto end;

FIG15 is a light fan diagram of the zoom lens provided in the second embodiment of the present utility model at the wide-angle end;

FIG16 is a light fan diagram of the zoom lens at the telephoto end provided by the second embodiment of the present utility model;

FIG17 is a schematic diagram of the structure of the zoom lens at the wide-angle end provided by Embodiment 3 of the present invention;

FIG18 is a schematic diagram of the structure of the zoom lens provided in Embodiment 3 of the present invention at the telephoto end;

FIG19 is a diagram of vertical axis chromatic aberration of the zoom lens provided in Embodiment 3 of the present utility model at the wide-angle end;

FIG20 is a diagram of vertical axis chromatic aberration of the zoom lens provided in Embodiment 3 of the present utility model at the telephoto end;

FIG21 is a diagram showing the field curvature distortion of the zoom lens provided in Embodiment 3 of the present invention at the wide-angle end;

FIG22 is a diagram showing the field curvature distortion of the zoom lens provided in Embodiment 3 of the present invention at the telephoto end;

FIG23 is a light fan diagram of the zoom lens provided in Embodiment 3 of the present utility model at the wide-angle end;

FIG. 24 is a light fan diagram of the zoom lens provided in Embodiment 3 of the present invention at the telephoto end.

DETAILED DESCRIPTION

In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

Embodiment 1

FIG1 is a schematic diagram of the structure of a zoom lens provided in Embodiment 1 of the present invention at a wide-angle end, and FIG2 is a schematic diagram of the structure of a zoom lens provided in Embodiment 1 of the present invention at a telephoto end. As shown in FIGS. 1 and 2, the zoom lens provided in Embodiment 1 of the present invention comprises a focus lens group G1 and a zoom lens group G2 which are sequentially arranged along the optical axis from the object plane to the image plane; the focal power of the focus lens group G1 is negative, and the focal power of the zoom lens group G2 is positive; the focus lens group G1 comprises a first lens 101 with a negative focal power, a second lens 102 with a negative focal power, and a third lens 103 with a positive focal power; the zoom lens group G2 comprises a fourth lens 104 with a positive focal power, a fifth lens 105 with a positive focal power, a sixth lens 106 with a negative focal power, a seventh lens 107 with a positive focal power, an eighth lens 108 with a negative focal power, and a ninth lens 109 with a positive focal power; and 13.88≤TTL/S1≤55.54;

2.47≤TTL/S2≤3.30; wherein TTL represents the total optical length of the zoom lens at the wide-angle end, S1 represents the maximum movable distance of the focus lens group, and S2 represents the maximum movable distance of the zoom lens group.

Specifically, in the zoom lens provided in this embodiment, the focus lens group G1 and the zoom lens group G2 can be arranged in a lens barrel (not shown in FIG. 1 ). 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, moving the focus lens group G1 can achieve a focusing effect, and moving the zoom lens group G2 can achieve a zooming effect. 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, so that the focal length of the zoom lens can achieve a continuous change from wide-angle to telephoto, ensuring that the zoom lens has high image quality at each focal position.

It can be understood that in the process of zooming by moving the focus lens group G1 and the zoom lens group G2, the zoom lens is located at the wide-angle end when the focal length is shortest, and is located at the telephoto end when the focal length is longest. At the wide-angle end and the telephoto end, the zoom lens has different focal lengths and optical focal powers, and also has different lengths or shapes.

Furthermore, the focal length is equal to the difference between the convergence of the image plane light beam and the convergence of the object plane light beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the 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 certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group). In an embodiment of the utility model, the focal length of the focusing lens group G1 is negative, and the focal length of the zoom lens group G2 is positive, which ensures that light can enter the subsequent structure through the focusing lens group G1 at a larger angle, ensuring the ultra-wide-angle characteristics of the zoom lens.

Furthermore, the first lens 101 and the second lens 102 are negative power lenses, which can effectively deflect incident light at large angles, ensuring that more light enters the optical system, thereby effectively increasing the field of view of the zoom lens and ensuring that the optical system has wide-angle characteristics. The third lens 103 is a positive power lens, so that the third lens 103 can timely correct the large aberrations generated by the first lens 101 and the second lens 102, especially the edge aberrations of the zoom lens, thereby improving the imaging resolution of the optical system.

Furthermore, 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 101 to the image plane. By limiting the total optical length TTL of the zoom lens at the wide-angle end and the maximum movable distance S1 of the focus lens group G1 to 13.88≤TTL/S1≤55.54, and the total optical length TTL of the zoom lens at the wide-angle end and the maximum movable distance S2 of the zoom lens group G2 to 2.47≤TTL/S2≤3.30, the lens space can be compressed, ensuring that the size of the zoom lens is small while meeting the requirements of imaging quality and high magnification.

In summary, the zoom lens provided by the embodiment of the utility model adopts a two-component structure and uses nine lenses. The zoom lens is provided to include a focus lens group with a negative optical power and a zoom lens group with a positive optical power. The focus lens group is provided to include a first lens with a negative optical power, a second lens with a negative optical power, and a third lens with a positive optical power. The zoom lens group is provided to include a fourth lens with a positive optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, a seventh lens with a positive optical power, an eighth lens with a negative optical power, and a ninth lens with a positive optical power. The total optical length TTL of the zoom lens at the wide-angle end, the maximum movable distance S1 of the focus lens group, and the zoom lens group are provided. The maximum movable distance S2 of the group satisfies 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30. By reasonably setting the optical focal length of each lens group, the number of lenses included in each lens group, the optical focal length of each lens, and the ratio between the total optical length at the wide-angle end and the maximum movable distance of different lens groups, the total optical length of the zoom lens is less than 51mm. Under the 1/2.7″ target surface, the aperture number FNO satisfies 1.59<FNO<4.26, and the resolution in the 436nm~850nm band is good, thereby realizing a zoom lens with small size, high magnification and simple structure, which meets the use requirements of clear imaging under the 1/2.7″ target surface.

On the basis of the above embodiment, with continued reference to FIG. 1 and FIG. 2 , the zoom lens further includes an aperture 110 , which is disposed in the optical path between the third lens 103 and the fourth lens 104 .

Specifically, the propagation direction of the light beam can be adjusted by setting the aperture 110, which is beneficial to improving the image quality. In addition, the aperture 110 in the zoom lens can be located in the optical path between the third lens 103 and the fourth lens 104, that is, the aperture 110 is set in the optical path between the focus lens group G1 and the zoom lens group G2, which can limit the incident angle of the light entering the subsequent structure, can reduce the high-order aberrations in the optical system, and play a role in improving the image quality.

On the basis of the above embodiments, with continued reference to FIG. 1 and FIG. 2 , the zoom lens provided by the embodiment of the utility model may further include a filter 111. The filter 111 is disposed in the light path between the ninth lens 109 and the image plane. The filter 111 may filter out interference light and improve the imaging effect of the zoom lens.

On the basis of the above embodiments, with continued reference to FIG. 1 and FIG. 2 , the zoom lens provided by the embodiment of the utility model may further include flat glass, which is arranged in the light path between the filter 111 and the image plane. The flat glass can protect the photosensitive chip in the imaging sensor, wherein the imaging 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.

Based on the above embodiment, -2.561≤F1/FW≤-1.041; 2.264≤F2/FW≤3.615; where F1 represents the focal length of the focus lens group, F2 represents the focal length of the zoom lens group, and FW represents the focal length of the zoom lens at the wide-angle end. This lens matching method is used to achieve a reasonable matching of optical power, so that light passes through the zoom lens more smoothly, and the influence of high-order aberrations on imaging quality is corrected to a great extent.

Based on the above embodiment, 4.206≤S2/S1≤22.473; wherein S1 represents the maximum movable distance of the focus lens group, and S2 represents the maximum movable distance of the zoom lens group. By controlling the moving distances of the focus lens group G1 and the zoom lens group G2, it is ensured that the moving range of the focus lens group G1 is reduced to the greatest extent, and the lens volume is greatly reduced.

On the basis of the above embodiment, 1.65≤nd1≤1.75; 47.60≤vd1≤60.00; 1.43≤nd4≤1.46; 90.00≤vd4≤96.00; 1.43≤nd7≤1.46; 90.00≤vd71≤96.00; 1.58≤nd8≤1.63; 38.00≤vd8≤47.00; wherein nd1 represents the refractive index of the first lens 101, and vd1 represents the Abbe number of the first lens 101; nd4 represents the refractive index of the fourth lens 104, and vd4 represents the Abbe number of the fourth lens 104; nd7 represents the refractive index of the seventh lens 107, and vd7 represents the Abbe number of the seventh lens 107; nd8 represents the refractive index of the eighth lens 108, and vd8 represents the Abbe number of the eighth lens 108.

Specifically, the refractive index is the ratio of the speed of light in a vacuum to the speed of light in the medium. It is mainly used to describe the material's ability to refract light. Different materials have different refractive indices, and the higher the refractive index of a material, the stronger its 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 less severe the dispersion of the medium, the larger the Abbe number.

In the embodiment of the utility model, the first lens 101 is set as a lens with a large refractive index and a high Abbe number so that the light has a larger incident aperture in front of the aperture 110, so that it can have a greater advantage in the correction of spherical aberration and the increase of image height. At the same time, when the second lens 102 and the third lens 103 are used in combination, the refractive index and Abbe number of the second lens 102 and the third lens 103 can better correct the influence of chromatic aberration on subsequent imaging, so that the optical system has a higher resolution while reducing the manufacturing cost. In addition, by controlling the refractive index and Abbe number of the seventh lens 107, the eighth lens 108 and the ninth lens 109, the maximum light aperture through the aperture STO can be controlled to avoid the influence of high-order aberrations. At the same time, when the lens refractive index and Abbe number are matched, it can also play a certain role in chromatic aberration control and obtain a wider imaging band range.

Based on the above embodiment, 4.5≤FT/FW≤6.0; wherein FT represents the focal length of the zoom lens at the telephoto end, and FW represents the focal length of the zoom lens at the wide-angle end. By controlling the focal length ratio of the zoom lens at the wide-angle end and the telephoto end, the lens can be confocal in the full band of 436nm to 850nm while ensuring that the resolution reaches 4MP, so that the zoom lens has a higher zoom ratio.

Based on the above embodiments, at least one of the first lens 101, the fourth lens 104, the seventh lens 107 and the eighth lens 108 is a glass spherical lens; the second lens 102, the third lens 103, the fifth lens 105, the sixth lens 106 and the ninth lens 109 are all plastic aspherical lenses.

Specifically, the characteristic of the aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike the spherical lens with a constant curvature from the center of the lens to the periphery of the lens, the aspherical lens has a better curvature radius characteristic and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting the aspherical lens, the aberration occurring during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens. In addition, the cost of plastic lenses is much lower than that of glass lenses and they are lightweight. From the cost point of view, the use of plastic aspherical lenses in the zoom lens can reduce costs on the one hand and reduce the weight of the lens on the other hand, so that it can meet the requirements of a wider range of uses. The characteristic of the spherical lens is that it has a constant curvature from the center of the lens to the periphery of the lens, which ensures that the lens is set in a simple manner. In addition, the thermal expansion coefficient of the glass lens is small and the stability is good. Therefore, the zoom lens includes a glass spherical lens, which can balance high and low temperatures. When the ambient temperature of the zoom lens changes greatly, it is beneficial to maintain the focal length of the zoom lens stable, for example, to ensure that the zoom lens has stable optical performance at -40℃ to 85℃.

Among them, the first lens 101 is at least a glass spherical lens, which can improve the stability of the system and reduce the manufacturing cost; the fourth lens 104 adopts a high-dispersion glass spherical lens, that is, the first lens in the zoom lens group G2 is a glass spherical lens, which can play a certain role in controlling the chromatic aberration of large-angle incident light after the aperture 110. Setting the fourth lens 104 as a positive optical power lens can balance the temperature refractive index deviation caused by other plastic aspherical surfaces in the optical system, which is beneficial to reducing the resolution degradation caused by temperature drift.

Furthermore, at least one of the first lens 101, the second lens 102 and the third lens 103 is an aspherical lens, the second lens 102 and the third lens 103 can be glued or not, and the glass-plastic hybrid lens combination can help correct the internal aberration of the focusing lens group G1 while controlling the cost, and avoid introducing new high-order aberrations when the focusing lens group G1 moves during the zooming process.

Furthermore, both the focus lens group G1 and the zoom lens group G2 have at least one plastic aspherical lens, which can further reduce the chromatic aberration and other high-order aberrations of the lens. At the same time, the aspherical lens is arranged before the aperture 110, and the aspherical lens after the aperture 110 is used to achieve the full-band confocality of the lens in the range of 436nm to 850nm, high magnification, and high image quality, which can meet the use requirements in more situations.

Furthermore, the zoom lens is provided with at least five plastic aspheric lenses, for example, the second lens 102, the third lens 103, the fifth lens 105, the sixth lens 106 and the ninth lens 109 are all plastic aspheric lenses, which can correct higher-order aberrations to a greater extent, achieve full-band confocality and high zoom ratio in the 436nm-850nm range of the lens, and improve image quality to meet the usage requirements in more situations.

It should be noted that the aspheric lenses in the zoom lenses provided in the embodiments of the utility model can all be plastic aspheric lenses, and lenses other than aspheric lenses can be spherical glass lenses. Among them, the two types of materials, glass and plastic, can compensate for each other, so as to balance high and low temperatures and reduce the total optical length of the lens, so that the zoom lens has the characteristics of stable high and low temperature performance, improve the environmental adaptability of the zoom lens, and at the same time better correct aberrations. By reasonably matching the temperature coefficient of the glass-plastic hybrid material, it can be ensured that the lens has good resolution in high and low temperature environments of -40℃ to 85℃, and the weight of the lens can be significantly reduced. In addition, compared with glass lenses, the cost of plastic lenses also has obvious advantages, which can reduce the cost of zoom lenses.

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.

On the basis of the above embodiment, the seventh lens 107 and the eighth lens 108 are glued together to form a double glued lens group, which can control the chromatic aberration of the lens after the aperture 110. At the same time, it can also effectively reduce the air gap between the seventh lens 107 and the eighth lens 108, which is helpful to reduce the total optical length of the 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 lens imaging.

It should be noted that the seventh lens 107 and the eighth lens 108 can be glued together according to actual usage requirements.

On the basis of the above embodiments, the first lens 101 includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is convex, and the first image-side surface is concave; the second lens 102 includes a second object-side surface close to the object plane and a second image-side surface close to the image plane, the second object-side surface is concave, and the second image-side surface is concave; the third lens 103 includes a third object-side surface close to the object plane, the third object-side surface is convex; the fourth lens 104 includes a fourth object-side surface close to the object plane and a fourth image-side surface close to the image plane, the fourth object-side surface is convex, and the fourth image-side surface is convex; the fifth lens 105 includes a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane. On the side, the fifth object side surface is convex, and the fifth image side surface is concave; the sixth lens 106 includes a sixth object side surface close to the object plane and a sixth image side surface close to the image plane, the sixth object side surface is concave, and the sixth image side surface is convex; the seventh lens 107 includes a seventh object side surface close to the object plane and a seventh image side surface close to the image plane, the seventh object side surface is convex, and the seventh image side surface is convex; the eighth lens 108 includes an eighth object side surface close to the object plane and an eighth image side surface close to the image plane, the eighth object side surface is concave, and the eighth image side surface is concave; the ninth lens 109 includes a ninth object side surface close to the object plane and a ninth image side surface close to the image plane, the ninth object side surface is convex, and the ninth image side surface is concave.

Specifically, the first object side surface is a convex surface, and the first image side surface is a concave surface, that is, the object side surface of the first lens 101 is convex toward the object plane, and the image side surface is concave toward the image plane, that is, the first lens 101 is a lens of a convex-concave structure. The second object side surface is a concave surface, and the second image side surface is a concave surface, that is, the object side surface of the second lens 102 is concave toward the object plane, and the image side surface is concave toward the image plane, that is, the second lens 102 is a lens of a double concave structure. The third object side surface is a convex surface, and the third image side surface is a convex surface, that is, the object side surface of the third lens 103 is convex toward the object plane, and the image side surface is convex toward the image plane, that is, the third lens 103 is a lens of a double convex structure. The fourth object side surface is a convex surface, and the fourth image side surface is a convex surface, that is, the object side surface of the fourth lens 104 is convex toward the object plane, and the image side surface is convex toward the image plane, that is, the fourth lens 104 is a lens of a double convex structure. The fifth object side surface is convex, and the fifth image side surface is concave, that is, the object side surface of the fifth lens 105 is convex toward the object plane, and the image side surface is concave toward the image plane, that is, the fifth lens 105 is a lens of a convex-concave structure. The sixth object side surface is concave, and the sixth image side surface is convex, that is, the object side surface of the sixth lens 106 is concave toward the object plane, and the image side surface is convex toward the image plane, that is, the sixth lens 106 is a lens of a concave-convex structure. The seventh object side surface is convex, and the image side surface is convex, that is, the object side surface of the seventh lens 105 is convex toward the object plane, and the image side surface is convex toward the image plane, that is, the seventh lens 107 is a lens of a double convex structure. The eighth object side surface is concave, and the eighth image side surface is concave, that is, the object side surface of the eighth lens 108 is concave toward the object plane, and the image side surface is concave toward the image plane, that is, the eighth lens 108 is a lens of a double concave structure. The ninth object side surface is a convex surface, and the ninth image side surface is a concave surface, that is, the object side surface of the ninth lens 109 is convex toward the object plane, and the image side surface is concave toward the image plane, that is, the ninth lens 109 is a lens with a convex-concave structure. By limiting the curvature direction of each lens surface, the focal length of each lens in the above embodiment is matched, and a zoom lens with small volume, high magnification, low cost, infrared and high and low temperature confocality is realized, and the gluing requirements between the lenses can also be met, which is beneficial to correcting the chromatic aberration and distortion of the lens, improving the imaging quality, and shortening the total optical length of the lens.

Furthermore, the design of the convex-concave structure of the first lens 101 is conducive to the collection of light, so as to ensure a larger field angle range of the zoom lens. The concave image side surface of the second lens 102 cooperates with the convex side surface of the third lens 103, which can shorten the total optical length of the focus lens group G1, thereby shortening the total length of the zoom lens. The concave image side surface of the eighth lens 108 cooperates with the convex side surface of the ninth lens 109, which can shorten the total optical length of the zoom lens group G2, thereby shortening the total length of the zoom lens.

As a feasible implementation, the parameters of each lens in the zoom lens are described below.

Table 1 Design values of optical physical parameters of a zoom lens

Surface number Surface type Radius of curvature thickness Materials (n.d.) Material (vd) Semi-caliber 1 Spherical INF Zoom interval 11.665 2 Spherical 22.352 0.696 1.68 50 8.848 3 Spherical 6.637 6.252 6.237 4 Aspheric -19.833 0.960 1.55 53 5.471 5 Aspheric 12.577 0.155 5.326 6 Aspheric 19.232 1.320 1.68 19 5.352 7 Aspheric -112.647 Zoom interval 5.250 8 Spherical INF 13.460 5.397 9 Spherical INF 10.425 5.127 10 Spherical INF Zoom interval 5.089 11 STO INF -2.200 4.925 12 Spherical 6.926 3.149 1.46 90 5.083 13 Spherical -86.381 0.172 5.083 14 Aspheric 13.069 1.831 1.55 53 4.654 15 Aspheric 215.005 0.647 4.372 16 Aspheric -20.407 1.277 1.68 19 4.282 17 Aspheric 95.853 0.076 4.151 18 Spherical 11.019 3.466 1.46 90 4.041 19 Spherical -5.149 1.478 1.63 38 4.041 20 Spherical 23.798 0.298 3.543 twenty one Aspheric 11.492 1.936 1.68 19 3.538 twenty two Aspheric 35.313 Zoom interval 3.685 twenty three Spherical INF 4.713 3.656 twenty four Spherical INF 0.700 1.52 64 3.515 25 Spherical INF 0.158 3.502 26 Spherical INF 0.032 3.497

The surface numbers in Table 1 are numbered according to the order of the surfaces of each lens. For example, surface number "1" represents the object surface, "2" represents the object side surface of the first lens 101, and surface number "3" represents the image side surface of the first lens 101, and so on. "STO" represents the aperture of the zoom lens. The radius of curvature represents the curvature of the lens surface. A positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side. "INF" represents that the surface is a plane and the radius of curvature is infinite. The thickness represents the central axis from the current surface to the next surface. The units of distance, radius of curvature and thickness are all millimeters (mm); material (nd) represents the refractive index, that is, the ability of the material between the current surface and the next surface to deflect light. A blank space represents that the current position is air, and the refractive index is 1; material (vd) represents the Abbe number (also called dispersion coefficient), that is, the dispersion characteristics of the material between the current surface and the next surface to light. A blank space represents that the current position is air, and the lenses and filters defined by material (nd) and material (vd) exist; the semi-aperture represents the corresponding half-height of the light on the surface of each lens.

Table 2 below shows the values of the zoom intervals of the zoom lens in Table 1 at the wide-angle end and the telephoto end.

Table 2 Design values of zoom intervals at the wide-angle end and telephoto end of a zoom lens

Wide-angle end Telephoto end Zoom interval 1 0.030 0.947 Zoom interval 2 -0.030 -0.947 Zoom interval 3 -0.030 -20.638 Zoom interval 4 0.030 20.638

The zoom intervals in Table 2 above are different interval values of the lens at the wide-angle end and the telephoto end.

In this embodiment, the aspherical lens of the zoom lens may satisfy the following formula:

Among them, Z is the axial distance from the curved surface at a position r perpendicular to the optical axis to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a10, a12, a14, a16, a18 and a20 are the high-order aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth, eighteenth and twentieth orders corresponding to the aspheric surface, and airi is combined into the high-order terms of the corresponding aspheric surface.

Exemplarily, Table 3 describes in detail the aspheric coefficients of each lens in the first embodiment in a feasible implementation manner.

Table 3 Design values of aspheric cone coefficients in a zoom lens

“-7.266E-04” means -7.266*10 ^-4 , and the other coefficients are expressed in this way.

The optical parameters of the optical system of this embodiment are shown in Table 4 below.

Table 4 Technical specifications of zoom lenses

Wide-angle end Telephoto end Image size(mm) Φ6.60 Φ6.60 Focal length(mm) 3.56 21.37 distortion(%) -42.16 -0.93 Wavelength(nm) 436～850 436～850 Total optical length (mm) 50.97 50.05

Further, FIG. 3 is a vertical axis chromatic aberration curve diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end, and FIG. 4 is a vertical axis chromatic aberration curve diagram of the zoom lens provided in the first embodiment of the present invention at the telephoto end, wherein, as shown in FIG. 3 and FIG. 4, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis direction 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). The maximum field of view in FIG. 3 is 58.0 degrees, and the maximum field of view in FIG. 4 is 10.7 degrees. It can be seen from Figures 3 and 4 that when the zoom lens is at the wide-angle end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-2μm, +14μm); when the zoom lens is at the telephoto end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-1μm, +6μm), 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.

FIG5 is a field curvature distortion diagram of the zoom lens provided in the first embodiment of the present invention at the wide-angle end, and FIG6 is a field curvature distortion diagram of the zoom lens provided in the first embodiment of the present invention at the telephoto end. As shown in FIG5 and FIG6, in the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, in units of mm; the vertical coordinate represents the normalized image height, without units; in the right coordinate system, the horizontal coordinate represents the magnitude of the distortion (F-Tan (Theta)), in units of %; the vertical coordinate represents the normalized image height, without units; the maximum field of view in FIG5 is 58.0 degrees, and the maximum field of view in FIG6 is 10.7 degrees. It can be seen from FIG5 and FIG6 that the zoom lens provided in this embodiment is effectively controlled in terms of field curvature at the wide-angle end and the telephoto end from light with a wavelength of 436nm to light with a wavelength of 850nm (specifically 436nm, 486nm, 546nm, 587nm, 656nm and 850nm), that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. At the same time, the distortion of the zoom lens at the wide-angle end is within -43%, and the distortion of the zoom lens at the telephoto end is within -1.0%. Therefore, the distortion of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is well corrected, and the imaging distortion is small.

FIG7 is a light fan diagram of the zoom lens provided in Example 1 of the present invention at the wide-angle end, and FIG8 is a light fan diagram of the zoom lens provided in Example 1 of the present invention at the telephoto end. The light fan diagram 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 diffusion 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 14μm, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, there is no obvious dispersion in the curves of each color, indicating that this zoom lens 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.

In summary, the zoom lens provided in the first embodiment of the present invention adopts a two-component structure and uses nine lenses. The zoom lens is provided to include a focus lens group with negative optical power and a zoom lens group with positive optical power. The focus lens group is provided to include a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power. The zoom lens group is provided to include a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with negative optical power and a ninth lens with positive optical power. The total optical length TTL of the zoom lens at the wide-angle end, the maximum movable distance S1 of the focus lens group and the maximum movable distance S2 of the zoom lens group are provided to satisfy 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30. The optical power of each lens group, the number of lenses included in each lens group, the optical power of each lens, and the ratio between the total optical length at the wide-angle end and the maximum movable distance of different lens groups are reasonably set. At the same time, by limiting the focal length of the focus lens group, the focal length of the zoom lens group, the focal length of the wide-angle end of the zoom lens, the maximum movable distance of the focus lens group, the maximum movable distance of the zoom lens group, the refractive index of some lenses, the Abbe number, the glass-plastic setting method of different lenses, the concave-convex method of the surface type and the bonding condition of the lenses, the total optical length of the zoom lens is made less than 51mm, and the aperture number FNO satisfies 1.59<FNO<4.26 at a 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 and simple structure, which meets the use requirements of clear imaging at a 1/2.7″ target surface.

Embodiment 2

FIG9 is a schematic diagram of the structure of the zoom lens provided in the second embodiment of the present invention at the wide-angle end, and FIG10 is a schematic diagram of the structure of the zoom lens provided in the second embodiment of the present invention at the telephoto end. As shown in FIG9 and FIG10, the zoom lens provided in the second embodiment of the present invention includes a focus lens group G1 and a zoom lens group G2 arranged in sequence from the object plane to the image plane along the optical axis; the optical power of the focus lens group G1 is negative, and the optical power of the zoom lens group G2 is positive; the focus lens group G1 includes a first lens 101 with a negative optical power, a second lens 102 with a negative optical power, and a third lens with a positive optical power. 103; the zoom lens group G2 includes a fourth lens 104 with positive optical power, a fifth lens 105 with positive optical power, a sixth lens 106 with negative optical power, a seventh lens 107 with positive optical power, an eighth lens 108 with negative optical power and a ninth lens 109 with positive optical power; and, 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30; wherein, TTL represents the total optical length of the zoom lens at the wide-angle end, S1 represents the maximum movable distance of the focus lens group, and S2 represents the maximum movable distance of the zoom lens group.

The configuration of the above-mentioned lens is the same as that in the first embodiment, and will not be described in detail here.

As another feasible implementation, specific parameters in the zoom lens are described below.

Table 5 Design values of optical physical parameters of a zoom lens

Surface number Surface type Radius of curvature thickness Materials (n.d.) Material (vd) Semi-caliber 1 Spherical INF Zoom interval 1 13.130 2 Spherical 13.938 0.698 1.65 60 8.530 3 Spherical 6.091 6.646 5.977 4 Aspheric -10.509 0.692 1.53 57 5.434 5 Aspheric 9.510 0.166 5.199 6 Aspheric 12.623 1.721 1.63 twenty four 5.280 7 Aspheric -64.728 Zoom interval 2 5.130 8 Spherical INF 13.180 5.118 9 Spherical INF 10.121 4.903 10 Spherical INF Zoom interval 3 5.236 11 STO INF -2.200 4.925 12 Spherical 7.749 2.987 1.43 96 5.068 13 Spherical -137.949 0.263 5.068 14 Aspheric 11.174 1.989 1.53 57 4.643 15 Aspheric 127.677 0.318 4.406 16 Aspheric -18.434 1.027 1.63 twenty four 4.387 17 Aspheric 100.452 0.916 3.970 18 Spherical 9.459 4.005 1.43 96 4.070 19 Spherical -5.092 1.266 1.6 46 4.070 20 Spherical 149.834 0.095 3.730 twenty one Aspheric 11.482 1.682 1.63 twenty four 3.723 twenty two Aspheric 30.387 Zoom interval 4 3.808 twenty three Spherical INF 4.539 3.753 twenty four Spherical INF 0.700 1.52 64 3.527 25 Spherical INF 0.158 3.504 26 Spherical INF 0.032 3.497

The surface numbers in Table 5 are numbered according to the order of the surfaces of each lens. For example, surface number "1" represents the object surface, "2" represents the object side surface of the first lens 101, and surface number "3" represents the image side surface of the first lens 101, and so on. "STO" represents the aperture of the zoom lens. The radius of curvature represents the curvature of the lens surface. A positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side. "INF" represents that the surface is a plane and the radius of curvature is infinite. The thickness represents the central axis from the current surface to the next surface. The units of distance, radius of curvature and thickness are all millimeters (mm); material (nd) represents the refractive index, that is, the ability of the material between the current surface and the next surface to deflect light. A blank space represents that the current position is air, and the refractive index is 1; material (vd) represents the Abbe number (also called dispersion coefficient), that is, the dispersion characteristics of the material between the current surface and the next surface to light. A blank space represents that the current position is air, and the lenses and filters defined by material (nd) and material (vd) exist; the semi-aperture represents the corresponding half-height of the light on the surface of each lens.

Table 6 below shows the values of the zoom intervals of the zoom lens in Table 5 at the wide-angle end and the telephoto end.

Table 6 Design values of zoom intervals at the wide-angle and telephoto ends of a zoom lens

Wide-angle end Telephoto end Zoom interval 1 0.085 1.771 Zoom interval 2 -0.085 -1.771 Zoom interval 3 -1.054 -19.230 Zoom interval 4 1.054 19.230

The zoom intervals in Table 6 above are different interval values for the lens at the wide-angle end and the telephoto end.

In this embodiment, the aspherical lens of the zoom lens may satisfy the following formula:

Among them, Z is the axial distance from the curved surface at a position r perpendicular to the optical axis to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a10, a12, a14, a16, a18 and a20 are the high-order aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth, eighteenth and twentieth orders corresponding to the aspheric surface, and airi is combined into the high-order terms of the corresponding aspheric surface.

Exemplarily, Table 7 describes in detail the aspheric coefficients of each lens in the second embodiment in a feasible implementation manner.

Table 7 Design values of aspheric cone coefficients in a zoom lens

Surface number k a ⁴ a ⁶ a ⁸ a ¹⁰ a ¹² a ¹⁴ 4 2.153 -3.096E-04 2.787E-05 -7.174E-07 7.064E-08 -3.350E-09 5.661E-11 5 -4.902 -5.355E-04 2.342E-05 -4.112E-07 -2.606E-08 -1.225E-09 7.279E-11 6 -3.748 -2.695E-04 2.865E-05 2.032E-08 -7.922E-08 7.217E-10 4.932E-11 7 90.635 -1.020E-04 1.474E-05 5.003E-07 -1.782E-08 -1.498E-09 5.346E-11 14 -1.686 -1.898E-04 -3.287E-05 -5.571E-07 2.057E-08 2.702E-09 -6.924E-11 15 12.052 -3.416E-04 -1.181E-04 3.294E-06 2.907E-07 2.887E-09 -6.864E-10 16 1.455 3.057E-04 -3.220E-05 4.757E-07 2.118E-07 1.498E-09 -5.623E-10 17 0.000 1.027E-04 2.101E-05 -1.317E-06 -1.041E-07 3.081E-09 -1.933E-11 twenty one -6.797 -8.557E-04 -7.574E-05 1.131E-06 -6.908E-08 -1.990E-08 1.155E-09 twenty two 7.661 -8.328E-04 -5.541E-05 1.784E-06 -4.039E-07 2.651E-08 -4.769E-10

"2.787E-05" means 2.787*10 ^-5 , and the other coefficients are expressed in this way.

The optical parameters of the optical system of this embodiment are shown in Table 8 below.

Table 8 Technical specifications of zoom lenses

Wide-angle end Telephoto end Image size(mm) Φ6.60 Φ6.60 Focal length(mm) 3.63 18.15 distortion(%) -43.26 -1.22 Wavelength(nm) 436～850 436～850 Total optical length (mm) 50.91 49.23

Further, FIG. 11 is a vertical axis chromatic aberration curve diagram of the zoom lens provided in the second embodiment of the present invention at the wide-angle end, and FIG. 12 is a vertical axis chromatic aberration curve diagram of the zoom lens provided in the second embodiment of the present invention at the telephoto end, wherein, as shown in FIG. 11 and FIG. 12, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis direction 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). The maximum field of view in FIG. 11 is 58.0 degrees, and the maximum field of view in FIG. 12 is 10.7 degrees. It can be seen from Figures 11 and 12 that when the zoom lens is at the wide-angle end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-1.5μm, +13μm); when the zoom lens is at the telephoto end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-1μm, +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.

FIG13 is a field curvature distortion diagram of the zoom lens provided in Example 2 of the present invention at the wide-angle end, and FIG14 is a field curvature distortion diagram of the zoom lens provided in Example 2 of the present invention at the telephoto end. As shown in FIGS. 13 and 14 , in the left coordinate system of the figures, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, in units of mm; the vertical coordinate represents the normalized image height, without units; in the right coordinate system, the horizontal coordinate represents the magnitude of the distortion (F-Tan (Theta)), in units of %; the vertical coordinate represents the normalized image height, without units; the maximum field of view in FIG13 is 58.0 degrees, and the maximum field of view in FIG14 is 10.7 degrees. As can be seen from FIG. 13 and FIG. 14, the zoom lens provided in this embodiment is effectively controlled in field curvature at the wide-angle end and the telephoto end for light with a wavelength of 436nm to 850nm (specifically 436nm, 486nm, 546nm, 587nm, 656nm and 850nm), that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. At the same time, the distortion of the zoom lens at the wide-angle end is within -44%, and the distortion of the zoom lens at the telephoto end is within -1.5%. Therefore, the distortion of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is well corrected, and the imaging distortion is small.

FIG15 is a light fan diagram of the zoom lens provided in Example 2 of the present invention at the wide-angle end, and FIG16 is a light fan diagram of the zoom lens provided in Example 2 of the present invention at the telephoto end. The light fan diagram 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 diffusion 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 14μm, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, there is no obvious dispersion in the curves of each color, indicating that this zoom lens 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.

In summary, the zoom lens provided in the second embodiment of the present invention adopts a two-component structure and uses nine lenses. The zoom lens is provided to include a focus lens group with negative optical power and a zoom lens group with positive optical power. The focus lens group is provided to include a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power. The zoom lens group is provided to include a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with negative optical power and a ninth lens with positive optical power. The total optical length TTL of the zoom lens at the wide-angle end, the maximum movable distance S1 of the focus lens group and the maximum movable distance S2 of the zoom lens group are provided to satisfy 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30. The optical power of each lens group, the number of lenses included in each lens group, the optical power of each lens, and the ratio between the total optical length at the wide-angle end and the maximum movable distance of different lens groups are reasonably set. At the same time, by limiting the focal length of the focus lens group, the focal length of the zoom lens group, the focal length of the wide-angle end of the zoom lens, the maximum movable distance of the focus lens group, the maximum movable distance of the zoom lens group, the refractive index of some lenses, the Abbe number, the glass-plastic setting method of different lenses, the concave-convex method of the surface type and the bonding condition of the lenses, the total optical length of the zoom lens is made less than 51mm, and the aperture number FNO satisfies 1.59<FNO<4.26 at a 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 and simple structure, which meets the use requirements of clear imaging at a 1/2.7″ target surface.

Embodiment 3

FIG17 is a schematic diagram of the structure of the zoom lens provided in the third embodiment of the present invention at the wide-angle end, and FIG18 is a schematic diagram of the structure of the zoom lens provided in the third embodiment of the present invention at the telephoto end. As shown in FIG17 and FIG18, the zoom lens provided in the third embodiment of the present invention comprises a focus lens group G1 and a zoom lens group G2 arranged in sequence from the object plane to the image plane along the optical axis; the optical focal length of the focus lens group G1 is negative, and the optical focal length of the zoom lens group G2 is positive; the focus lens group G1 comprises a first lens 101 with a negative optical focal length, a second lens 102 with a negative optical focal length, and a third lens 103 with a positive optical focal length. Mirror 103; the zoom lens group G2 includes a fourth lens 104 with positive optical focal power, a fifth lens 105 with positive optical focal power, a sixth lens 106 with negative optical focal power, a seventh lens 107 with positive optical focal power, an eighth lens 108 with negative optical focal power and a ninth lens 109 with positive optical focal power; and 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30; wherein TTL represents the total optical length of the zoom lens at the wide-angle end, S1 represents the maximum movable distance of the focus lens group, and S2 represents the maximum movable distance of the zoom lens group.

The configuration of the above-mentioned lens is the same as that in the first embodiment, and will not be described in detail here.

As another feasible implementation, specific parameters in the zoom lens are described below.

Table 9 Design values of optical physical parameters of a zoom lens

Surface number Surface type Radius of curvature thickness Materials (n.d.) Material (vd) 1 Spherical INF Zoom interval 12.526 2 Spherical 20.377 0.698 1.75 51 9.085 3 Spherical 7.337 7.667 6.665 4 Aspheric -12.878 0.867 1.54 56 5.199 5 Aspheric 9.795 0.170 4.945 6 Aspheric 13.567 1.846 1.65 twenty two 4.800 7 Aspheric -60.316 Zoom interval 4.978 8 Spherical INF 13.413 5.047 9 Spherical INF 10.431 4.771 10 Spherical INF Zoom interval 5.411 11 STO INF -2.200 4.925 12 Spherical 7.559 3.014 1.44 93 5.071 13 Spherical -101.207 0.074 5.071 14 Aspheric 13.122 2.042 1.54 56 4.686 15 Aspheric 107.234 0.353 4.401 16 Aspheric -20.020 0.668 1.65 twenty two 4.358 17 Aspheric 110.370 0.588 4.000 18 Spherical 9.171 4.009 1.44 93 4.123 19 Spherical -5.402 1.522 1.58 47 4.123 20 Spherical 110.731 0.098 3.670 twenty one Aspheric 11.801 1.741 1.65 twenty two 3.652 twenty two Aspheric 18.706 Zoom interval 3.731 twenty three Spherical INF 3.110 3.613 twenty four Spherical INF 0.700 1.52 64 3.519 25 Spherical INF 0.158 3.505 26 Spherical INF 0.032 3.500

The surface numbers in Table 9 are numbered according to the order of the surfaces of each lens. For example, surface number "1" represents the object surface, "2" represents the object side surface of the first lens 101, and surface number "3" represents the image side surface of the first lens 101, and so on. "STO" represents the aperture of the zoom lens. The radius of curvature represents the curvature of the lens surface. A positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side. "INF" represents that the surface is a plane and the radius of curvature is infinite. The thickness represents the central axis from the current surface to the next surface. The units of distance, radius of curvature and thickness are all millimeters (mm); material (nd) represents the refractive index, that is, the ability of the material between the current surface and the next surface to deflect light. A blank space represents that the current position is air, and the refractive index is 1; material (vd) represents the Abbe number (also called dispersion coefficient), that is, the dispersion characteristics of the material between the current surface and the next surface to light. A blank space represents that the current position is air, and the lenses and filters defined by material (nd) and material (vd) exist; the semi-aperture represents the corresponding half-height of the light on the surface of each lens.

Table 10 below shows the values of the zoom intervals of the zoom lens in Table 9 at the wide-angle end and the telephoto end.

Table 10 Design values of zoom intervals at the wide-angle end and telephoto end of a zoom lens

Wide-angle end Telephoto end Zoom interval 1 0.088 3.755 Zoom interval 2 -0.088 -3.755 Zoom interval 3 -2.358 -17.782 Zoom interval 4 2.358 17.782

The zoom intervals in Table 10 above are different interval values for the lens at the wide-angle end and the telephoto end.

In this embodiment, the aspherical lens of the zoom lens may satisfy the following formula:

Among them, Z is the axial distance from the curved surface at a position r perpendicular to the optical axis to the vertex of the surface along the optical axis; c represents the curvature at the vertex of the aspheric surface; a4, a6, a8, a10, a12, a14, a16, a18 and a20 are the high-order aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth, eighteenth and twentieth orders corresponding to the aspheric surface, and airi is combined into the high-order terms of the corresponding aspheric surface.

Exemplarily, Table 11 describes in detail the aspheric coefficients of each lens in the third embodiment in a feasible implementation manner.

Table 11 Design values of aspheric cone coefficients in a zoom lens

Surface number k a ⁴ a ⁶ a ⁸ a ¹⁰ a ¹² a ¹⁴ 4 1.324 -7.085E-04 3.038E-05 -5.862E-07 2.276E-09 1.183E-11 3.271E-12 5 -9.920 -5.893E-04 1.720E-05 1.583E-06 -8.065E-08 -2.740E-09 1.389E-10 6 -8.067 -4.712E-04 3.250E-05 4.357E-07 -4.077E-08 -2.520E-09 1.088E-10 7 66.201 -8.663E-05 1.343E-05 7.536E-08 -1.050E-08 -2.065E-10 1.106E-11 14 -2.290 -1.750E-04 -3.783E-05 -5.453E-07 3.799E-08 2.924E-09 -9.611E-11 15 -251.274 -1.556E-04 -1.025E-04 2.170E-06 2.815E-07 3.506E-09 -6.554E-10 16 -2.079 4.139E-04 -1.948E-05 5.558E-07 1.589E-07 -3.914E-10 -4.612E-10 17 0.000 1.419E-04 2.065E-05 -3.245E-07 -9.835E-08 -3.314E-09 1.610E-10 twenty one -11.598 -1.168E-03 -5.592E-05 -2.320E-06 -7.019E-08 -9.876E-09 1.002E-09 twenty two -29.943 -7.478E-04 -4.153E-05 -1.027E-06 -4.498E-07 5.301E-08 -1.462E-09

"3.038E-05" means 3.038*10 ^-5 , and the other coefficients are expressed in this way.

The optical parameters of the optical system of this embodiment are shown in Table 15 below.

Table 12 Technical specifications of zoom lenses

Wide-angle end Telephoto end Image size(mm) Φ6.60 Φ6.60 Focal length(mm) 3.63 16.33 distortion(%) -42.99 -1.02 Wavelength(nm) 436-850 436-850 Total optical length (mm) 50.91 47.25

Further, FIG. 19 is a vertical axis chromatic aberration curve diagram of the zoom lens provided in the third embodiment of the present invention at the wide-angle end, and FIG. 20 is a vertical axis chromatic aberration curve diagram of the zoom lens provided in the third embodiment of the present invention at the telephoto end, wherein, as shown in FIG. 19 and FIG. 20, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the vertex in the vertical axis direction 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). The maximum field of view in FIG. 19 is 58.0 degrees, and the maximum field of view in FIG. 20 is 10.7 degrees. It can be seen from Figures 19 and 20 that when the zoom lens is at the wide-angle end, the vertical chromatic aberration of different wavelengths is controlled within the range of (-1μm, +14μm); when the zoom lens is at the telephoto end, the vertical chromatic aberration of different wavelengths is controlled within the range of (0μm, +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.

FIG21 is a field curvature distortion diagram of the zoom lens provided in Example 3 of the present invention at the wide-angle end, and FIG22 is a field curvature distortion diagram of the zoom lens provided in Example 3 of the present invention at the telephoto end. As shown in FIG21 and FIG22, in the left coordinate system of the figure, the horizontal coordinate represents the magnitude of the field curvature of the zoom lens, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; in the right coordinate system, the horizontal coordinate represents the magnitude of the distortion (F-Tan (Theta)), and the unit is %; the vertical coordinate represents the normalized image height, and there is no unit; the maximum field of view in FIG21 is 58.0 degrees, and the maximum field of view in FIG22 is 10.7 degrees. As can be seen from FIG. 21 and FIG. 22, the zoom lens provided in this embodiment is effectively controlled in field curvature at the wide-angle end and the telephoto end for light with a wavelength of 436nm to 850nm (specifically 436nm, 486nm, 546nm, 587nm, 656nm and 850nm), that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. At the same time, the distortion of the zoom lens at the wide-angle end is within -43%, and the distortion of the zoom lens at the telephoto end is within -1%. Therefore, the distortion of the zoom lens provided in this embodiment at the wide-angle end and the telephoto end is well corrected, and the imaging distortion is small.

FIG23 is a light fan diagram of the zoom lens provided in the third embodiment of the present invention at the wide-angle end, and FIG24 is a light fan diagram of the zoom lens provided in the third embodiment of the present invention at the telephoto end. The light fan diagram 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 14μm, indicating that the vertical axis aberration of each wavelength is well corrected. In addition, there is no obvious dispersion in the curves of each color, indicating that this zoom lens 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.

In summary, the zoom lens provided in the third embodiment of the present invention adopts a two-component structure and uses nine lenses. The zoom lens is provided to include a focus lens group with negative optical power and a zoom lens group with positive optical power. The focus lens group is provided to include a first lens with negative optical power, a second lens with negative optical power and a third lens with positive optical power. The zoom lens group is provided to include a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with negative optical power and a ninth lens with positive optical power. The total optical length TTL of the zoom lens at the wide-angle end, the maximum movable distance S1 of the focus lens group and the maximum movable distance S2 of the zoom lens group are provided to satisfy 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30. The optical power of each lens group, the number of lenses included in each lens group, the optical power of each lens, and the ratio between the total optical length at the wide-angle end and the maximum movable distance of different lens groups are reasonably set. At the same time, by limiting the focal length of the focus lens group, the focal length of the zoom lens group, the focal length of the wide-angle end of the zoom lens, the maximum movable distance of the focus lens group, the maximum movable distance of the zoom lens group, the refractive index of some lenses, the Abbe number, the glass-plastic setting method of different lenses, the concave-convex method of the surface type and the bonding condition of the lenses, the total optical length of the zoom lens is made less than 51mm, and the aperture number FNO satisfies 1.59<FNO<4.26 at a 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 and simple structure, which meets the use requirements of clear imaging at a 1/2.7″ target surface.

On the basis of the above three embodiments, in order to more clearly illustrate the above embodiments, Table 13 details the specific optical physical parameters of each lens in the zoom lens provided by Embodiments 1 to 3 of the present invention.

Table 13 Design values of optical physical parameters of zoom lens

The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims (10)

1. A zoom lens, characterized in that it comprises a focus lens group and a zoom lens group arranged in sequence from an object plane to an image plane along an optical axis; the optical power of the focus lens group is negative, and the optical power of the zoom lens group is positive; The focusing lens group includes a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power; The zoom lens group includes a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, a seventh lens with positive optical power, an eighth lens with negative optical power and a ninth lens with positive optical power; And, 13.88≤TTL/S1≤55.54; 2.47≤TTL/S2≤3.30; Wherein, TTL represents the total optical length of the zoom lens at the wide-angle end, S1 represents the maximum movable distance of the focus lens group, and S2 represents the maximum movable distance of the zoom lens group. 2. The zoom lens according to claim 1, wherein -2.561≤F1/FW≤-1.041; 2.264≤F2/FW≤3.615; Among them, F1 represents the focal length of the focus lens group, F2 represents the focal length of the zoom lens group, and FW represents the focal length of the zoom lens at the wide-angle end. 3. The zoom lens according to claim 1, wherein 4.206≤S2/S1≤22.473; Among them, S1 represents the maximum movable distance of the focus lens group, and S2 represents the maximum movable distance of the zoom lens group. 4. The zoom lens according to claim 1, wherein: 1.65≤nd1≤1.75; 47.60≤vd1≤60.00; 1.43≤nd4≤1.46; 90.00≤vd4≤96.00; 1.43≤nd7≤1.46; 90.00≤vd71≤96.00; 1.58≤nd8≤1.63; 38.00≤vd8≤47.00; Among them, nd1 represents the refractive index of the first lens, and vd1 represents the Abbe number of the first lens; nd4 represents the refractive index of the fourth lens, and vd4 represents the Abbe number of the fourth lens; nd7 represents the refractive index of the seventh lens, and vd7 represents the Abbe number of the seventh lens; nd8 represents the refractive index of the eighth lens, and vd8 represents the Abbe number of the eighth lens. 5 . The zoom lens according to claim 1 , wherein 4.5≤FT/FW≤6.0; wherein FT represents the focal length of the zoom lens at a telephoto end, and FW represents the focal length of the zoom lens at a wide-angle end. 6. The zoom lens according to claim 1, wherein at least one of the first lens, the fourth lens, the seventh lens and the eighth lens is a glass spherical lens; The second lens, the third lens, the fifth lens, the sixth lens and the ninth lens are all plastic aspherical lenses. 7. The zoom lens according to claim 1, wherein the first lens comprises a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is a convex surface, and the first image-side surface is a concave surface; The second lens comprises a second object-side surface close to the object plane and a second image-side surface close to the image plane, the second object-side surface is a concave surface, and the second image-side surface is a concave surface; The third lens comprises a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is a convex surface, and the third image-side surface is a convex surface; The fourth lens comprises a fourth object-side surface close to the object plane and a fourth image-side surface close to the image plane, the fourth object-side surface is a convex surface, and the fourth image-side surface is a convex surface; The fifth lens comprises a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane, the fifth object-side surface is a convex surface, and the fifth image-side surface is a concave surface; The sixth lens comprises a sixth object-side surface close to the object plane and a sixth image-side surface close to the image plane, the sixth object-side surface is a concave surface, and the sixth image-side surface is a convex surface; The seventh lens comprises a seventh object-side surface close to the object plane and a seventh image-side surface close to the image plane, the seventh object-side surface is a convex surface, and the seventh image-side surface is a convex surface; The eighth lens comprises an eighth object-side surface close to the object plane and an eighth image-side surface close to the image plane, the eighth object-side surface is a concave surface, and the eighth image-side surface is a concave surface; The ninth lens includes a ninth object-side surface close to the object plane and a ninth image-side surface close to the image plane. The ninth object-side surface is a convex surface, and the ninth image-side surface is a concave surface. 8 . The zoom lens according to claim 1 , wherein the seventh lens and the eighth lens are cemented together. 9 . The zoom lens according to claim 1 , further comprising an aperture stop, wherein the aperture stop is disposed in an optical path between the third lens and the fourth lens. 10 . The zoom lens according to claim 1 , further comprising a filter, wherein the filter is disposed in the optical path between the ninth lens and the image plane.