CN216927242U

CN216927242U - Zoom lens

Info

Publication number: CN216927242U
Application number: CN202123070183.9U
Authority: CN
Inventors: 沈悦; 王言壮; 蓝岚
Original assignee: Sunny Optics Zhongshan Co Ltd
Current assignee: Sunny Optics Zhongshan Co Ltd
Priority date: 2021-12-08
Filing date: 2021-12-08
Publication date: 2022-07-08
Anticipated expiration: 2031-12-08

Abstract

The utility model relates to a zoom lens, which sequentially comprises the following components in the direction from an object side to an image side along an optical axis: the zoom lens system comprises a compensation lens group (G1) with negative focal power, a Stop (STO), a fixed lens group (G2) with positive focal power and a variable power lens group (G3) with positive focal power, wherein in the process of zooming, the fixed lens group (G2) is fixed relative to an image surface (IMA) in position, and the compensation lens group (G1) and the variable power lens group (G3) move along an optical axis. The zoom lens can realize at least 3 times of zooming under the condition of a certain total length of an optical system, and has good performances of large-aperture zooming, high resolution and infrared confocal at the same time, and the cost is low.

Description

Zoom lens

Technical Field

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

Background

The zoom lens has variable focal length, can meet the requirements of various monitoring scenes, and is concerned about in the field of security monitoring. With the rapid popularization and development of security monitoring, higher requirements are made on the image acquisition function of the zoom lens. If the zoom lens adopts a large aperture, although the large aperture can ensure that enough light rays are captured in a dark field and at night, the defects of obvious aberration and insufficiently clear imaging are also brought. In addition, in order to expand the use scene and application prospect of the zoom lens, the security monitoring field generally requires that the camera lens has infrared confocal performance and the characteristic of image undistortion at high and low temperatures. In general, a zoom optical system has high resolution, infrared confocal performance, and high and low temperature performance, and it is difficult to reduce the cost. Therefore, it is also important to consider reducing the manufacturing cost thereof at the same time.

The zoom lens disclosed in chinese patent CN113534425A adopts a four-group optical architecture of two-fixed-one zoom-one focus, and has the characteristics of large aperture, large target surface and low cost, but cannot be compatible with infrared confocal performance. Meanwhile, the four-group structure reduces the zoom stroke of the zoom group on the basis of limiting the total length, so that the zoom ratio is between 2 and 2.5 times, and the zoom of more than 3 times cannot be realized.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects in the prior art, the present invention provides a zoom lens, which can achieve at least 3 times of zooming under a certain total length of an optical system, achieve large aperture zooming and high resolution, and has the excellent characteristics of infrared confocal property and low cost.

To achieve the above object, the present invention provides a zoom lens, sequentially comprising, in a direction from an object side to an image side along an optical axis: the zoom lens system comprises a compensation lens group with negative focal power, a diaphragm, a fixed lens group with positive focal power and a zoom lens group with positive focal power, wherein in the zooming process, the fixed lens group is fixed relative to the position of an image surface, and the compensation lens group and the zoom lens group move along an optical axis.

According to an aspect of the present invention, the compensation lens group includes, in order from the object side to the image side along the optical axis, a first lens having negative power, a second lens having negative power, and a third lens having positive power.

According to an aspect of the present invention, in a direction from an object side to an image side along an optical axis,

the first lens and the third lens are both convex and concave lenses;

the second lens is concave-convex or convex-concave in shape at the paraxial region.

According to an aspect of the utility model, the second lens and the third lens are both plastic aspheric lenses.

According to an aspect of the present invention, a distance Δ D by which the compensation lens group is moved from a wide-angle end to a telephoto end of the zoom lens and a distance TTL _ W by which the zoom lens is moved from a front surface vertex of the first lens to an image plane at the wide-angle end satisfy a relational expression: 1.56 ≦ (Δ D/TTL _ W) 10| ≦ 1.92.

According to an aspect of the present invention, the fixed lens group includes a fourth lens having positive power,

the fourth lens is a concave-convex lens along the direction from the object side to the image side of the optical axis.

According to one aspect of the utility model, the fourth lens is a plastic aspheric lens.

According to an aspect of the present invention, the variable power lens group includes, in order from an object side to an image side along an optical axis, a fifth lens having positive power, a sixth lens having positive power, a seventh lens having negative power, an eighth lens having positive power, a ninth lens having negative power, a tenth lens having positive power, and an eleventh lens having negative power;

the eighth lens and the ninth lens are cemented to form a cemented lens.

the fifth lens is a convex or concave lens;

the sixth lens and the seventh lens are both convex and concave lenses;

the eighth lens is a convex lens;

the ninth lens is a concave-concave type or concave-convex type lens;

the tenth lens is a convex or concave-convex lens;

the eleventh lens is convex-concave in shape at the paraxial region.

According to an aspect of the utility model, the sixth lens, the seventh lens and the eleventh lens are all plastic aspheric lenses, and the tenth lens is a plastic aspheric lens or a glass spherical lens.

According to an aspect of the utility model, the refractive index nd5 of the fifth lens satisfies the relation: nd5 is more than or equal to 1.52 and less than or equal to 1.65;

the refractive index nd8 of the eighth lens satisfies the relation: nd8 is more than or equal to 1.42 and less than or equal to 1.62.

According to an aspect of the present invention, a focal length F5 of the fifth lens and a focal length fiii of the variable power lens group satisfy the relation: F5/FIII is more than or equal to 1.15 and less than or equal to 1.72.

According to an aspect of the present invention, in the cemented lens, an abbe number vd8 of the eighth lens and an abbe number vd9 of the ninth lens satisfy the relation: 36 is not less than vd8-vd9 is not more than 68.

According to an aspect of the present invention, a focal length FB of the cemented lens and a focal length fiii of the variable power lens group satisfy a relation: 1.82 is less than or equal to | FB/FIII |.

According to an aspect of the present invention, a focal length F6 of the sixth lens and a focal length fiii of the variable power lens group satisfy the relation: F6/FIII is more than or equal to 2.96 and less than or equal to 4.50;

the focal length F7 of the seventh lens and the focal length F III of the variable power lens group satisfy the relation: F7/FIII is more than or equal to-2.42 and less than or equal to-1.55;

a focal length F10 of the tenth lens and a focal length fiii of the variable power lens group satisfy the relation: F10/FIII is more than or equal to 0.85 and less than or equal to 2.11;

the focal length F11 of the eleventh lens and the focal length F III of the variable power lens group satisfy the relation: 13.74 ℃ below zero F11/FIII ℃ below zero-2.52.

According to an aspect of the present invention, a focal length fii of the fixed lens group and a focal length Fw of the zoom lens at the wide-angle end satisfy the relation: the absolute value of F II/Fw is more than or equal to 29.76 and less than or equal to 50.81.

According to an aspect of the present invention, a focal length fi of the compensation lens group and a focal length fiii of the variable power lens group satisfy a relation: f I/F III is more than or equal to-0.88 and less than or equal to-0.50.

According to the scheme of the utility model, the zoom lens adopts a three-group structure of 'one zoom, one focusing and one fixing', and the total number of the zoom lens comprises 11 lenses. By reasonably configuring the focal power of each lens and different shapes on the object side surface and the image side surface and adopting a zooming mode of fixing the position of the fixed lens group relative to the image surface and moving the compensation lens group and the variable-power lens group along the optical axis, the zoom lens can realize at least 3 times of zooming under the condition of certain total length of an optical system and simultaneously has good performances of large-aperture zooming, high resolution and infrared confocal.

According to one scheme of the utility model, the specific glass lens and the plastic lens are mixed and matched, so that the zoom lens can still ensure good resolution at the high temperature of 80 ℃ and the low temperature of-40 ℃, and the zoom lens is free from virtual focus at the high temperature and the low temperature. And moreover, the low-cost glass lens is adopted, so that the performance is ensured, and meanwhile, the low-cost glass lens is realized.

According to one scheme of the utility model, lens parameters such as focal power, refractive index, Abbe number, distance and the like of specific lenses and cemented lenses in three groups and among the three groups as well as in the three groups are reasonably configured, so that various aberrations, spherical aberration and chromatic aberration of the zoom lens are effectively corrected, the transmissibility of light is improved, focusing can be better realized in the zooming process, high-definition imaging under the conditions of large zoom ratio, large aperture zooming and infrared is realized, the focusing efficiency is improved, and the full-focus imaging quality is ensured at the same time.

Drawings

Fig. 1 schematically shows a schematic configuration of an optical system wide-angle end of a zoom lens according to embodiment 1 of the present invention;

fig. 2 is a schematic view showing a configuration of a telephoto end of an optical system of a zoom lens according to embodiment 1 of the present invention;

fig. 3 is a view schematically showing visible RAY FAN at the wide angle end of an optical system of a zoom lens system according to embodiment 1 of the present invention;

fig. 4 is a view schematically showing visible RAY FAN at the telephoto end of the optical system of the zoom lens according to embodiment 1 of the present invention;

fig. 5 schematically shows a structural schematic view of an optical system wide-angle end of a zoom lens according to embodiment 2 of the present invention;

fig. 6 is a schematic view showing a configuration of a telephoto end of an optical system of a zoom lens according to embodiment 2 of the present invention;

fig. 7 is a view schematically showing visible RAY FAN at the wide angle end of an optical system of a zoom lens system according to embodiment 2 of the present invention;

fig. 8 is a view schematically showing visible RAY FAN at the telephoto end of the optical system of the zoom lens according to embodiment 2 of the present invention;

fig. 9 is a schematic view showing the configuration of an optical system wide-angle end of a zoom lens system according to embodiment 3 of the present invention;

fig. 10 is a schematic view showing a configuration of a telephoto end of an optical system of a zoom lens according to embodiment 3 of the present invention;

fig. 11 is a view schematically showing visible RAY FAN at the wide angle end of an optical system of a zoom lens system according to embodiment 3 of the present invention;

fig. 12 is a schematic view showing a visible RAY FAN at the telephoto end of the optical system of the zoom lens system according to embodiment 3 of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the utility model, and that for a person skilled in the art, other drawings can also be derived from them without inventive effort.

In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer" are used in an orientation or positional relationship that is based on the orientation or positional relationship shown in the associated drawings, which is for convenience in describing and simplifying the description, and is not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore the terms described above are not to be construed as limiting the utility model.

The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are not limited to the following embodiments.

Fig. 1 and 2 schematically show structural schematic diagrams of an optical system wide-angle end and a telephoto end, respectively, of a zoom lens according to an embodiment of the present invention.

As shown in fig. 1 or fig. 2, the zoom lens of the present invention includes: the compensation lens group G1, the stop STO, the fixed lens group G2, and the variable power lens group G3 are arranged in this order in the direction from the object side to the image side along the optical axis. Wherein the compensation lens group G1 has negative power, and the fixed lens group G2 and the variable power lens group G3 both have positive power. In the zooming process, the fixed lens group G2 is fixed relative to the position of the image plane IMA, and the compensation lens group G1 and the zooming lens group G3 can move along the optical axis, so that the zoom lens can realize high-quality imaging on the full focal length section in the whole zooming process. In one embodiment of the present invention, relative positional relationships of the fixed lens group G2, the compensation lens group G1, and the variable power lens group G3 of the zoom lens at the wide-angle end and the telephoto end are respectively as shown in fig. 1 and fig. 2.

In the present invention, the compensation lens group G1 includes, in the direction from the object side to the image side along the optical axis, a first lens L1, a second lens L2, and a third lens L3, which are arranged in this order. Among them, the first lens L1 has a negative power, and the second lens L2 and the third lens L3 both have a positive power. The object-side surfaces of the first lens L1 and the third lens L3 are convex, and the image-side surfaces thereof are concave. The object-side surface of the second lens L2 is concave or convex in shape at the paraxial region, and the image-side surface thereof is concave in shape at the paraxial region.

The fixed lens group G2 includes a fourth lens L4 having positive power. The object-side surface of the fourth lens L4 is convex, and the image-side surface thereof is concave.

The variable power lens group G3 includes a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, and an eleventh lens L11, which are arranged in this order. Among them, the fifth lens L5, the sixth lens L6, the eighth lens L8, and the tenth lens L10 all have positive power, and the seventh lens L7, the ninth lens L9, and the eleventh lens L11 all have negative power. The object-side surface of the fifth lens element L5 is convex, and the image-side surface thereof is convex or concave. The object-side surfaces of the sixth lens L6 and the seventh lens L7 are both convex, and the image-side surfaces thereof are both concave. The object-side surface and the image-side surface of the eighth lens L8 are both convex. The object-side surface of the ninth lens L9 is concave, and the image-side surface thereof is concave or convex. The object side of the tenth lens L10 is convex or concave, and the image side thereof is convex. The object side surface of the eleventh lens L11 is convex in shape at the paraxial region, and the image side surface thereof is concave in shape at the paraxial region.

The zoom optical system of the utility model adopts three groups of optical structures of 'one zoom, one focusing and one fixing', and reasonably configures the focal power of each lens in each group and the lens shapes of the image side surface and the object side surface, so that the three groups all form specific focal power, the zoom lens can realize at least 3 times of zoom under the condition of certain total length of the optical system, and simultaneously has good performances of large aperture, high resolution and infrared confocal, and the zoom ratio of the lens is improved.

In the present invention, the refractive index nd5 of the fifth lens L5 satisfies the relation: nd5 is more than or equal to 1.52 and less than or equal to 1.65; the refractive index nd8 of the eighth lens L8 satisfies the relation: nd8 is more than or equal to 1.42 and less than or equal to 1.62. Therefore, high-definition imaging of the zoom lens under an infrared condition is guaranteed by reasonably configuring the refractive indexes of the fifth lens L5 and the eighth lens L8.

The eighth lens L8 and the ninth lens L9 are cemented to constitute a cemented lens. The Abbe number vd8 of the eighth lens L8 and the Abbe number vd9 of the ninth lens L9 in the cemented lens satisfy the relation: 36 is not less than vd8-vd9 is not more than 68. Therefore, by arranging the cemented lens and reasonably configuring and matching the Abbe number of the cemented lens, the spherical aberration and chromatic aberration of the whole optical system are well corrected, and the imaging sharpness of the zoom lens is further ensured.

The focal length fii of the fixed lens group G2 and the focal length Fw of the zoom lens at the wide-angle end satisfy the relation: 29.76 is less than or equal to all but F II/Fw is less than or equal to 50.81. The power distribution mode of the group of the fixed lens group G2 and the whole optical system of the zoom lens is beneficial to reducing the height of light rays after the light rays pass through the fixed lens group G2 and realizing large-aperture zooming.

The focal length FI of the compensation lens group G1 and the focal length FIII of the variable power lens group G3 satisfy the relation: f I/F III is more than or equal to-0.88 and less than or equal to-0.50. Through the power distribution mode of the group of the compensation lens group G1 and the whole optical system of the zoom lens, the light can be better transmitted, the better focusing in the zooming process is facilitated, and the imaging quality is ensured.

A distance Δ D of the variable power lens group G3 moving from the wide angle end to the telephoto end of the zoom lens and a distance TTL _ W of the zoom lens from the front surface vertex of the first lens L1 to the image plane IMA at the wide angle end satisfy the relation: 1.56 ≦ (Δ D/TTL _ W) 10| ≦ 1.92. The front surface vertex here refers to an intersection of the object side surface of the first lens L1 and the optical axis. Thereby, at least a large zoom ratio can be achieved with a small group interval variation amount during zooming from the wide-angle end to the telephoto end. Meanwhile, under the condition that the total length of the optical system of the zoom lens is limited, the zooming efficiency is improved.

The focal length F5 of the fifth lens L5 in the variable power lens group G3 and the focal length fiii of the variable power lens group G3 satisfy the relationship: F5/FIII is more than or equal to 1.15 and less than or equal to 1.72. The power distribution relationship between the fifth lens L5 and the variable power lens group G3 is favorable for improving the light transmission between the groups, and can realize a large zoom ratio as much as possible under a certain total length of the zoom lens optical system, thereby having a larger variable power group stroke and being favorable for better ensuring the imaging quality of a full focus section.

The focal length FB of the cemented lens in the variable magnification lens group G3 and the focal length IIII of the variable magnification lens group G3 satisfy the relation: 1.82 is less than or equal to | FB/FIII |. Therefore, by distributing the focal power between the group of the cemented lens and the variable power lens group G3 according to the relationship, the transmissibility of the light rays can be further improved, so that the light rays are further converged, and high-definition imaging of the zoom lens under a large aperture is facilitated.

The second lens L2 and the third lens L3 of the compensation lens group G1, the fourth lens L4 of the fixed lens group G2, and the sixth lens L6, the seventh lens L7, and the eleventh lens L11 of the variable power lens group G3 are all plastic aspherical lenses, and the tenth lens L10 of the variable power lens group G3 is a plastic aspherical lens or a glass spherical lens. By reasonably configuring different surface types of the aspheric surface and the spherical surface of each lens in the three-group framework, various aberrations of the zooming optical system are effectively corrected, so that the resolution of the zoom lens is improved, and high-definition resolution of imaging is realized. Meanwhile, by skillfully matching and using glass and plastic materials, the back focal drift of the zoom lens at high and low temperatures is perfectly compensated, and the clear imaging of the zoom lens at the extreme temperature condition is ensured. And the reasonable distribution of the focal power of each lens ensures that the zoom optical system can still ensure good resolution at the high temperature of 80 ℃ and the low temperature of-40 ℃ without virtual focus at the high temperature and the low temperature. In addition, the utility model can still ensure various performances of the zoom optical system under the condition of adopting less glass lenses, and simultaneously greatly reduces the production cost.

In the variable power lens group G3, the following relational expressions are satisfied between the focal length F6 of the sixth lens L6, the focal length F7 of the seventh lens L7, the focal length F10 of the tenth lens L10, and the focal length F11 of the eleventh lens L11, and the focal length fiii of the variable power lens group G3, respectively:

2.96≤F6/FⅢ≤4.50；

-2.42≤F7/FⅢ≤-1.55；

0.85≤F10/FⅢ≤2.11；

and-13.74. ltoreq. F11/FIII. ltoreq-2.52.

According to the above relationship, the positive and negative powers of the sixth lens L6, the seventh lens L7, the tenth lens L10 and the eleventh lens L11 in the variable power lens group G3 are respectively matched with the positive and negative powers of the variable power lens group G3, which is beneficial to the aberration correction of the zoom lens and effectively ensures that the zoom optical system is not virtual focus in the high and low temperature states.

In summary, the zoom lens of the present invention is an optical system with three groups of "one zoom, one focus and one fixed", and comprises 11 lenses in total. By reasonably configuring the focal power of each lens and the different shapes of the object side surface and the image side surface and adopting a zooming mode of fixing the position of the fixed lens group G2 relative to the image surface and moving the compensation lens group G1 and the variable power lens group G3 along the optical axis, the zoom lens can realize at least 3 times of zooming under the condition of certain total length of an optical system, and simultaneously has good performances of large-aperture zooming, high resolution and infrared confocal. And moreover, the low-cost glass lens is adopted, so that the performance is ensured, and meanwhile, the low-cost glass lens is realized. And the specific glass lens and the plastic lens are mixed and matched, so that the zoom lens can still ensure good resolution at the high temperature of 80 ℃ and the low temperature of-40 ℃, and the zoom lens does not have virtual focus at the high temperature and the low temperature.

The zoom lens of the present invention is specifically described below in five embodiments. In the following embodiments, the zoom lens of the present invention includes 11 lenses, one stop STO, one parallel plate CG and an image plane IMA. Here, the stop STO is referred to as a first surface STO, the image plane IMA is referred to as a first surface IMA, and a cemented surface of a double cemented lens including the eighth lens L8 and the ninth lens L9 is referred to as a first surface. The lenses and the parallel plate CG have two surfaces, respectively.

The parameters of each example specifically corresponding to the above relationship are shown in table 1 below:

conditional formula (VII)	Example 1	Example 2	Example 3
				29.76≤\|FⅡ/Fw\|≤50.81	36.02	49.81	30.76
-0.88≤FⅠ/FⅢ≤-0.50	-0.71	-0.73	-0.72
				1.56≤\|(ΔD/TTL_W)*10\|≤1.92	1.84	1.74	1.78
1.15≤F5/FⅢ≤1.72	1.31	1.45	1.53
				1.82≤\|FB/FⅢ\|	4.44	7.32	2.32
1.52≤nd5≤1.65	1.62	1.55	1.55
				1.42≤nd8≤1.62	1.44	1.59	1.55
36≤vd8-vd9≤68	66.36	38.86	42.94
				2.96≤F6/FⅢ≤4.50	3.16	3.19	3.30
-2.42≤F7/FⅢ≤-1.55	-1.67	-1.88	-2.23
				0.85≤F10/FⅢ≤2.11	1.02	1.09	1.91
-13.74≤F11/FⅢ≤-2.52	-13.54	-11.85	-2.72

TABLE 1

In various embodiments of the present invention, the surface type of the aspherical lens of the zoom lens satisfies the following formula:

wherein Z represents curvature at a position of height y perpendicular to the optical axis in the direction of the optical axisFace-to-apex axial distance; c represents the curvature at the apex of the aspherical surface; k represents a conic coefficient; a. the₄、A₆、A₈、A₁₀、A₁₂、A₁₄、A₁₆Respectively representing aspheric coefficients of fourth order, sixth order, eighth order, tenth order, twelfth order, fourteen order and sixteenth order.

Example 1

Referring to fig. 1 and 2, in the present embodiment, the tenth lens L10 is a plastic aspheric lens.

Focal length: 3.14-9.41 mm;

F number:1.26–2.31。

relevant parameters of each lens of the zoom lens of the present embodiment, including the surface type, the value of the radius of curvature R, the thickness d, the refractive index nd and the abbe number vd of the material, S1 to S24 represent each surface of each lens, the cemented lens, the stop STO and the parallel plate CG in the zoom lens, as shown in table 2 below.

TABLE 2

The aspheric coefficients of the aspheric lenses of the zoom lens of the present embodiment include the conic constant K value and the fourth-order aspheric coefficient a₄Sixth order aspherical surface coefficient A₆Eighth order aspheric surface coefficient A₈Ten-order aspheric surface coefficient A₁₀And a twelfth order aspherical surface coefficient A₁₂As shown in table 3 below.

TABLE 3

When the wide-angle end of the zoom lens of the present embodiment is changed to the telephoto end, the numerical values of the intervals are variable as shown in table 4 below.

Surface number	Thickness of	Wide angle end	Telescope end
				6	D1	11.46	1.90
9	D2	8.49	0.42
				22	D3	4.50	12.57

TABLE 4

Fig. 3 and 4 show the optical aberration effects of the zoom lens of the present embodiment at the wide angle end and the telephoto end, respectively. As shown in fig. 1 to 4 and associated design parameters and data in tables 1 to 4, it can be seen that the zoom lens of the present embodiment can achieve at least 3 times of zooming under a certain total length of the optical system, and has a large aperture, high resolution, and infrared confocal property, thereby ensuring full focal length imaging quality. By adopting the reasonable matching of the glass lens and the plastic lens, the performances of the zoom lens are still ensured under the condition of using less glass lenses, and the cost is greatly reduced. Through the specific material selection of the lens and the reasonable focal power matching, the zoom lens can still ensure good resolution ratio at the high temperature of 80 ℃ and the low temperature of-40 ℃, and does not have virtual focus at the high temperature and the low temperature.

Example 2

Referring to fig. 5 and 6, in the present embodiment, the tenth lens L10 is a plastic aspheric lens.

Focal length: 3.13-9.38 mm;

F number:1.26-2.38。

relevant parameters of each lens of the zoom lens of the present embodiment, including the surface type, the value of the radius of curvature R, the thickness d, the refractive index nd and the abbe number vd of the material, S1 to S24 represent each surface of each lens, the cemented lens, the stop STO and the parallel plate CG in the zoom lens, as shown in table 5 below.

TABLE 5

The aspheric coefficients of the aspheric lenses of the zoom lens of the present embodiment include the conic constant K value and the fourth-order aspheric coefficient a₄Sixth order aspherical surface coefficient A₆Eighth order aspheric surface coefficient A₈Ten-order aspheric surface coefficient A₁₀And a twelfth order aspherical surface coefficient A₁₂As shown in table 6 below.

Surf.No

K

A₄

A₆

A₈

A₁₀

A₁₂

3

-1.10E+01

-8.09E-04

2.30E-05

-5.40E-07

7.58E-09

-4.40E-11

4

1.82E-01

-1.02E-03

-1.38E-05

6.82E-07

-1.18E-08

-3.67E-11

5

-3.57E-01

-1.56E-06

-2.52E-05

1.10E-06

-1.57E-08

-4.53E-11

6

3.30E+01

-2.16E-05

5.76E-06

-9.87E-08

2.23E-09

-1.50E-10

8

2.99E+01

-4.01E-04

-8.88E-08

-4.72E-08

-4.72E-09

1.08E-10

9

4.04E+01

-3.68E-04

2.33E-06

-2.25E-07

6.56E-09

-1.10E-10

12

3.17E+00

-1.56E-04

1.05E-06

-8.29E-07

7.95E-09

1.28E-10

13

6.25E+01

6.01E-04

-2.92E-06

-6.48E-07

9.63E-09

-6.74E-10

14

6.70E+00

-1.28E-03

3.01E-05

8.60E-07

-2.75E-08

-6.62E-10

15

2.05E-01

-1.97E-03

3.83E-05

-3.51E-08

1.78E-08

-1.12E-09

19

3.77E+01

1.69E-03

-1.66E-04

7.99E-06

-1.02E-07

7.36E-09

20

-7.93E+00

-9.13E-04

-4.47E-05

2.54E-06

-9.12E-08

8.44E-09

21

-1.23E+00

-7.80E-03

-4.90E-06

4.58E-06

-4.82E-08

-1.38E-08

22

-4.41E+00

-6.50E-03

1.28E-04

1.52E-06

-2.47E-07

6.56E-09

TABLE 6

When the wide-angle end of the zoom lens of the present embodiment is changed to the telephoto end, the numerical values of the intervals are variable as shown in table 7 below.

Surface number	Thickness of	Wide angle end	Telescope end
				6	D1	11.04	2.01
9	D2	8.47	0.43
				22	D3	4.50	12.54

TABLE 7

Fig. 7 and 8 show the light ray aberration effects at the wide angle end and the telephoto end, respectively, of the zoom lens of the present embodiment. As shown in fig. 5 to 8 and associated design parameters and data in tables 1 and 5 to 7, the zoom lens of the present embodiment can achieve at least 3 times of zooming under a certain total optical length condition, and has a large aperture, high resolution, and infrared confocal property, thereby ensuring full focal length imaging quality. By adopting the reasonable matching of the glass lens and the plastic lens, the performances of the zoom lens are still ensured under the condition of using less glass lenses, and the cost is greatly reduced. Through the specific material selection of the lens and the reasonable optical power collocation, the zoom lens can still ensure good resolution ratio at the high temperature of 80 ℃ and the low temperature of minus 40 ℃, and virtual focus is not generated at the high temperature and the low temperature.

Example 3

Referring to fig. 9 and 10, in the present embodiment, the tenth lens L10 is a glass spherical lens.

Focal length: 3.13-9.38 mm;

F number:1.25–2.31。

relevant parameters of each lens of the zoom lens of the present embodiment, including the surface type, the value of the radius of curvature R, the thickness d, the refractive index nd and the abbe number vd of the material, S1 to S24 represent each surface of each lens, the cemented lens, the stop STO and the parallel plate CG in the zoom lens, as shown in table 8 below.

TABLE 8

The aspheric coefficients of the aspheric lenses of the zoom lens of the present embodiment include the conic constant K value and the fourth-order aspheric coefficient a₄Sixth order aspherical surface coefficient A₆Eighth order aspheric surface coefficient A₈Ten-order aspheric surface coefficient A₁₀And a twelfth order aspherical surface coefficient A₁₂As shown in table 9 below.

Surf.No

K

A₄

A₆

A₈

A₁₀

A₁₂

3

5.69E+01

-6.82E-04

1.29E-05

-1.60E-07

7.40E-10

2.01E-24

4

-2.14E-01

-1.03E-03

-8.68E-06

9.58E-07

-1.99E-08

1.95E-24

5

-2.83E-01

-1.85E-04

-1.81E-05

1.09E-06

-2.00E-08

1.91E-24

6

5.21E+00

-3.16E-04

8.67E-07

8.19E-08

-4.90E-09

1.93E-24

8

2.33E+01

-5.44E-04

-4.28E-06

-5.97E-08

-2.38E-09

2.00E-24

9

-4.73E+01

-3.96E-04

-3.25E-07

-9.73E-08

1.74E-09

1.99E-24

12

2.80E+00

-3.97E-04

8.09E-06

-9.62E-07

6.63E-09

1.99E-24

13

5.07E+01

8.06E-04

-4.72E-06

-6.59E-07

1.33E-10

1.98E-24

14

5.79E+00

-1.04E-03

1.42E-05

2.78E-07

-1.86E-08

1.99E-24

15

6.97E-02

-2.25E-03

2.85E-05

2.19E-07

-3.71E-08

1.98E-24

21

1.35E+01

-6.25E-03

6.84E-05

4.30E-06

-1.72E-07

1.99E-24

22

-3.92E+00

-4.95E-03

1.65E-04

2.30E-07

-8.08E-08

1.99E-24

TABLE 9

When the wide angle end of the zoom lens of the present embodiment is changed to the telephoto end, the numerical values of the intervals are variable as shown in table 10 below.

Surface number	Thickness of	Wide angle end	The telescope end
				6	D1	11.49	2.50
9	D2	8.25	0.46
				22	D3	4.71	12.50

Watch 10

Fig. 11 and 12 show the optical aberration effects at the wide angle end and the telephoto end, respectively, of the zoom lens of the present embodiment. As shown in fig. 9 to 12 and associated design parameters and data in tables 1 and 8 to 10, the zoom lens of the present embodiment can achieve at least 3 times of zooming under a certain total optical length condition, and has a large aperture, high resolution, and infrared confocal property, thereby ensuring full focal length imaging quality. By adopting the reasonable matching of the glass lens and the plastic lens, the performances of the zoom lens are still ensured under the condition of using less glass lenses, and the cost is greatly reduced. Through the specific material selection of the lens and the reasonable focal power matching, the zoom lens can still ensure good resolution ratio at the high temperature of 80 ℃ and the low temperature of-40 ℃, and does not have virtual focus at the high temperature and the low temperature.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A zoom lens, comprising, in order from an object side to an image side along an optical axis: a compensation lens group (G1) with negative focal power, a diaphragm (STO), a fixed lens group (G2) with positive focal power and a variable power lens group (G3) with positive focal power,

during zooming, the fixed lens group (G2) is fixed in position relative to the image plane (IMA), and the compensation lens group (G1) and the zoom lens group (G3) move along the optical axis;

the variable power lens group (G3) sequentially comprises a fifth lens (L5) with positive focal power, a sixth lens (L6) with positive focal power, a seventh lens (L7) with negative focal power, an eighth lens (L8) with positive focal power, a ninth lens (L9) with negative focal power, a tenth lens (L10) with positive focal power and an eleventh lens (L11) with negative focal power.

2. The zoom lens according to claim 1, wherein the compensation lens group (G1) includes, in order from the object side to the image side along the optical axis, a first lens (L1) having negative optical power, a second lens (L2) having negative optical power, and a third lens (L3) having positive optical power.

3. The zoom lens according to claim 2, wherein, in a direction from the object side to the image side along the optical axis,

the first lens (L1) and the third lens (L3) are both convex-concave lenses;

the second lens (L2) has a concave-convex shape at the paraxial region.

4. The zoom lens according to claim 2, wherein the second lens (L2) and the third lens (L3) are both plastic aspherical lenses.

5. A zoom lens according to claim 2, wherein a distance (Δ D) by which the compensation lens group (G1) moves from a wide-angle end to a telephoto end of the zoom lens and a distance (TTL _ W) by which the zoom lens at the wide-angle end from a front surface vertex of the first lens (L1) to the image plane (IMA) satisfy the relation: 1.56 ≦ (Δ D/TTL _ W) 10| ≦ 1.92.

6. A zoom lens according to claim 1, wherein the fixed lens group (G2) includes a fourth lens (L4) whose optical power is positive,

the fourth lens (L4) is a convex-concave lens in a direction from the object side to the image side along the optical axis.

7. The zoom lens according to claim 6, wherein the fourth lens (L4) is a plastic aspherical lens.

8. The zoom lens according to claim 1,

the eighth lens (L8) and the ninth lens (L9) are cemented to constitute a cemented lens.

9. The zoom lens according to claim 1, wherein, in a direction from the object side to the image side along the optical axis,

the fifth lens (L5) is a convex or concave lens;

the sixth lens (L6) and the seventh lens (L7) are both convex-concave lenses;

the eighth lens (L8) is a convex-type lens;

the ninth lens (L9) is a concave-concave type or a concave-convex type lens;

the tenth lens (L10) is a convex or concave-convex lens;

the eleventh lens (L11) has a concave-convex shape at the paraxial region.

10. The zoom lens according to claim 1, wherein the sixth lens (L6), the seventh lens (L7) and the eleventh lens (L11) are all plastic aspherical lenses, and the tenth lens (L10) is a plastic aspherical lens or a glass spherical lens.

11. A zoom lens according to claim 1, wherein the refractive index (nd5) of the fifth lens (L5) satisfies the relation: nd5 is more than or equal to 1.52 and less than or equal to 1.65;

a refractive index (nd8) of the eighth lens (L8) satisfies the relation: nd8 is more than or equal to 1.42 and less than or equal to 1.62.

12. A zoom lens according to claim 1, wherein a focal length (F5) of the fifth lens (L5) and a focal length (fiii) of the variable power lens group (G3) satisfy the relation: F5/FIII is more than or equal to 1.15 and less than or equal to 1.72.

13. A zoom lens according to claim 8, wherein the Abbe number (vd8) of the eighth lens (L8) and the Abbe number (vd9) of the ninth lens (L9) in the cemented lens satisfy the relation: 36 is not less than vd8-vd9 is not more than 68.

14. A zoom lens according to claim 8, characterized in that the focal length (FB) of the cemented lens and the focal length (FIII) of the variable power lens group (G3) satisfy the relation: | FB/FIII | is more than or equal to 1.82.

15. A zoom lens according to claim 1, wherein a focal length (F6) of the sixth lens (L6) and a focal length (fiii) of the variable power lens group (G3) satisfy the relation: F6/FIII is more than or equal to 2.96 and less than or equal to 4.50;

a focal length (F7) of the seventh lens (L7) and a focal length (fiii) of the variable power lens group (G3) satisfy the relation: F7/FIII is more than or equal to-2.42 and less than or equal to-1.55;

a focal length (F10) of the tenth lens (L10) and a focal length (fiii) of the variable power lens group (G3) satisfy the relation: F10/FIII is more than or equal to 0.85 and less than or equal to 2.11;

a focal length (F11) of the eleventh lens (L11) and a focal length (fiii) of the variable power lens group (G3) satisfy the relation: 13.74 ℃ below zero F11/FIII ℃ below zero-2.52.

16. A zoom lens according to any one of claims 1 to 15, wherein the focal length (fi) of the fixed lens group (G2) and the focal length (Fw) of the zoom lens at the wide-angle end satisfy the relationship: 29.76 is less than or equal to all but F II/Fw is less than or equal to 50.81.

17. A zoom lens according to any one of claims 1 to 15, wherein the focal length (fi) of the compensation lens group (G1) and the focal length (fiii) of the variable power lens group (G3) satisfy the relationship: f I/F III is more than or equal to-0.88 and less than or equal to-0.50.