CN215813530U

CN215813530U - Zoom lens

Info

Publication number: CN215813530U
Application number: CN202121611432.8U
Authority: CN
Inventors: 聂路鑫; 黄慧; 梁伟朝
Original assignee: Sunny Optics Zhongshan Co Ltd
Current assignee: Sunny Optics Zhongshan Co Ltd
Priority date: 2021-07-15
Filing date: 2021-07-15
Publication date: 2022-02-11
Anticipated expiration: 2031-07-15

Abstract

The utility model relates to a zoom lens, which comprises a first fixed lens group with positive focal power, a zoom lens group with negative focal power, an aperture diaphragm, a second fixed lens group with positive focal power, a focusing lens group with positive focal power and a third fixed lens group which are sequentially arranged from an object side to an image side along an optical axis, wherein the zoom lens group and the focusing lens group can move along the optical axis direction. The zoom lens provided by the utility model realizes small volume, large aperture, day and night confocal, does not generate virtual focus in high and low temperature environments, and realizes full-focus 4K high-resolution imaging. And the cost is reduced by adopting the plastic aspheric lens.

Description

Zoom lens

Technical Field

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

Background

The high-end market of the security industry has higher and higher requirements on the definition of pictures, and the 4K resolution ratio gradually becomes the mainstream. The telescopic end resolution of the existing large-magnification zoom lens is mostly at the level of 2M and 4M, and the market demand cannot be met. Since the zoom ratio of the zoom lens and the front end aperture and the total length of the lens have a mutually restricted relationship, it is difficult to achieve miniaturization. If the zoom lens adopts a large aperture, although enough light can be captured in a dark field and at night, the effects of obvious aberration and insufficiently clear imaging are often brought. In addition, the security field generally requires that the camera lens has infrared confocal performance and the characteristic of image undistortion at high and low temperatures. That is, the zoom system needs to give consideration to high resolution, infrared confocal, and high-low temperature image undistortion performance. In order to ensure lens resolution, it is difficult to achieve low cost using a glass aspherical lens.

In order to solve the above problem, prior art CN201310185215.0 discloses a high-pixel macro-focus large-magnification zoom optical system. The system is provided with a first lens group, a second lens group, a third lens group, a fourth lens group and a fifth lens group in sequence from a shot object to an image surface, and the focal lengths of the first lens group, the second lens group, the third lens group, the fourth lens group and the fifth lens group are respectively positive, negative, positive and positive. The first lens group and the third lens group are fixed relative to the image surface, the second lens group, the fourth lens group and the fifth lens group can move forwards and backwards relative to the image surface along the object direction, and a diaphragm is arranged between the second lens group and the third lens group. The five lens groups comprise fifteen optical glass spherical lenses in total, and an optical filter is arranged between the fifteenth lens and the image surface. Although the proposal solves the problems of large volume and low resolution of the zoom optical system, the zoom optical system is made of glass spherical lenses, so that the zoom optical system has high cost and heavy weight. In addition, the performance of satisfying infrared confocal and high and low temperature image undistortion at the same time is not mentioned.

Disclosure of Invention

In order to make up for the above defects, an object of the present invention is to provide a zoom lens which has a small size and simultaneously has high resolution, infrared confocal performance and high and low temperature image undistorted performance.

To achieve the above object, the present invention provides a zoom lens including: the zoom lens group and the focus lens group can move along the optical axis direction, and the focal power of the third fixed lens group is negative.

According to one aspect of the utility model, the focal length FG1 of the first fixed lens group satisfies: FG1/Fw is more than or equal to 3 and less than or equal to 5.5;

a focal length FG2 of the zoom lens group satisfies: FG2/Fw is less than or equal to-1.8 and less than or equal to-0.6;

a focal length FG3 of the second fixed lens group satisfies: FG3/Fw is more than or equal to 1 and less than or equal to 2.8;

a focal length FG4 of the focus lens group satisfies: FG4/Fw is more than or equal to 1.5 and less than or equal to 4;

a focal length FG5 of the third fixed lens group satisfies: FG5/Fw is less than or equal to-3;

where Fw is the focal length at the wide-angle end of the zoom lens.

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 fixed lens group sequentially comprises a first lens with negative focal power, a second lens with positive focal power and a third lens with positive focal power;

the first lens and the second lens are glued to form a gluing lens group.

the first lens and the third lens are of a convex-concave type;

the second lens is convex-convex.

the zoom lens group sequentially comprises a fourth lens with negative focal power, a fifth lens with negative focal power, a sixth lens with positive focal power and a seventh lens with negative focal power;

and the fifth lens and the sixth lens are glued to form a gluing lens group.

the fourth lens is of a convex-concave type;

the fifth lens is concave-concave;

the sixth lens is convex-convex;

the paraxial region of the seventh lens is convex-concave.

the second fixed lens group sequentially comprises an eighth lens with positive focal power, a ninth lens with positive focal power, a tenth lens with negative focal power, an eleventh lens with negative focal power, a twelfth lens with positive focal power and a thirteenth lens with negative focal power;

the eleventh lens and the twelfth lens or the eleventh lens, the twelfth lens and the thirteenth lens are cemented to form a cemented lens group.

the eighth lens, the ninth lens, and the twelfth lens are convex-convex;

the tenth lens and the thirteenth lens are concave-concave;

the eleventh lens is of a convex-concave type.

According to one aspect of the utility model, the refractive indexes Nd of the eighth lens, the ninth lens and the tenth lens all satisfy the relation: nd is less than or equal to 1.68.

According to an aspect of the utility model, an abbe number Vb8 of the eighth lens satisfies the relation: vb8 is more than or equal to 60 and less than or equal to 96.

According to an aspect of the present invention, the focus lens group includes, in order from the object side to the image side along the optical axis, a fourteenth lens having positive optical power, a fifteenth lens having negative optical power, and a sixteenth lens having positive optical power.

the fourteenth lens is convex-concave;

the fifteenth lens and the sixteenth lens are of a concave-convex type.

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

the seventeenth lens is of a concave-convex type;

the paraxial region of the eighteenth lens is concave-concave.

According to an aspect of the present invention, at least 3 of the lenses included in the zoom lens are aspheric lenses; wherein at least 2 of the aspheric lenses are made of plastic material.

According to an aspect of the present invention, the zoom lens comprises at least 3 cemented lens groups formed by cementing adjacent lenses.

According to one aspect of the utility model, the diameter phi I of the target surface covered by the zoom lens and the total length TTL of the zoom lens satisfy the relation: phi I/TTL is more than or equal to 0.070 and less than or equal to 0.110.

According to an aspect of the present invention, the absolute value of the stroke D2 of the zoom lens group and the total length TTL of the zoom lens satisfy the relation: D2/TTL is more than or equal to 0.3 and less than or equal to 0.4.

According to an aspect of the present invention, the absolute value of stroke D4 of the focus lens group and the absolute value of stroke D2 of the zoom lens group satisfy the relation: D4/D2 is more than or equal to 0 and less than or equal to 0.2.

According to the scheme provided by the utility model, the zoom lens is provided, the small volume, the large aperture, the large target surface, the day and night confocal property and the virtual focus resistance in the high and low temperature environment are realized, and the full focus section meets the 4K resolution. In addition, the plastic aspheric lens is used, so that low cost is realized.

According to one scheme of the utility model, a five-group framework of the first fixed lens group, the zoom lens group, the second fixed lens group, the focusing lens group and the third fixed lens group is adopted, so that the zoom lens can realize a large target surface phi 9.1 and a maximum aperture can reach F1.4. Meanwhile, the focal power of the first fixed lens group is positive, and the focal power of the zoom lens group is negative, so that light rays with large angles or large calibers can enter the rear lens group, and the larger zoom magnification is realized. The full-focus 4K imaging can be realized while the performance requirements of large multiplying power, small volume, large aperture and large target surface are met.

According to one scheme of the utility model, through reasonable optical power distribution and selection of specific glass materials, chromatic aberration and secondary spectrum chromatic aberration correction of a zoom lens at a telephoto end of 380-940 nm are realized. The reasonable arrangement of the cemented lens group can satisfy the full focus infrared confocal.

According to one scheme of the utility model, through reasonably matching the temperature coefficients of the refractive indexes of the specific materials of the lenses, virtual focus and image distortion are avoided within the temperature range of-40-80 ℃, and the full focus section realizes 4K high-resolution imaging.

According to one aspect of the present invention, a cost reduction of the zoom lens is achieved by using a plastic aspherical lens in a rational manner.

Drawings

FIG. 1 is a schematic view showing a configuration of a zoom lens according to a first embodiment of the present invention;

fig. 2 schematically shows an MTF chart at the wide-angle end of a zoom lens according to a first embodiment of the present invention;

FIG. 3 is a schematic view showing an MTF chart at the telephoto end of a zoom lens according to a first embodiment of the present invention;

FIG. 4 is a schematic view showing a configuration of a zoom lens according to a second embodiment of the present invention;

FIG. 5 schematically shows an MTF chart at the wide-angle end of a zoom lens according to a second embodiment of the present invention;

FIG. 6 is a schematic view showing an MTF chart at the telephoto end in a zoom lens according to a second embodiment of the present invention;

FIG. 7 is a schematic view showing a configuration of a zoom lens according to a third embodiment of the present invention;

FIG. 8 schematically shows an MTF chart at the wide-angle end of a zoom lens according to a third embodiment of the present invention;

fig. 9 schematically shows an MTF chart at the telephoto end in a zoom lens according to a third embodiment 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 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," and the like 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 and simplicity of description only, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above-described terms should not be construed as limiting the present invention.

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.

Referring to fig. 1, the zoom lens of the present invention includes, in order from an object side to an image side along an optical axis, a first fixed lens group G1 having positive optical power, a zoom lens group G2 having negative optical power, an aperture stop STO, a second fixed lens group G3 having positive optical power, a focus lens group G4 having positive optical power, and a third fixed lens group G5 having negative optical power. The focal power of the first fixed lens group G1 is positive, and the focal power of the zoom lens group G2 is negative, so that light rays with large angles or large apertures can enter the rear lens group, and a large zoom magnification is realized. The zoom lens group G2 is movable in the optical axis direction for achieving optical zooming of the zoom lens between the wide-angle end and the telephoto end. The focusing lens group G4 can also move along the optical axis direction to compensate for the image plane position variation during optical zooming. In the using process, the focusing lens group G4 is properly adjusted to be offset with the conjugate distance variation generated by the zooming lens group G2 under the conditions of a far object and a micro distance, so that the image plane compensation is realized, and a high-quality image picture is obtained.

In the present invention, the focal length FG1 of the first fixed lens group G1 satisfies: FG1/Fw is more than or equal to 3 and less than or equal to 5.5; the focal length FG2 of the zoom lens group G2 satisfies: FG2/Fw is less than or equal to-1.8 and less than or equal to-0.6; the focal length FG3 of the second fixed lens group G3 satisfies: FG3/Fw is more than or equal to 1 and less than or equal to 2.8; the focal length FG4 of the focus lens group G4 satisfies: FG4/Fw is more than or equal to 1.5 and less than or equal to 4; the focal length FG5 of the third fixed lens group G5 satisfies: FG5/Fw is less than or equal to-3. Where Fw is the focal length at the wide-angle end of the zoom lens. By setting the ratio range between each lens group and the focal length at the wide-angle end of the zoom lens, while the movement of the zoom lens group G2 on the optical axis realizes zooming, the focusing lens group G4 can compensate for aberrations by moving on the optical axis, realizing sharp imaging.

In the present invention, the first fixed 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 positive optical power, and a third lens L3 having positive optical power. The first lens L1 and the second lens L2 are cemented to form a cemented lens group. The first lens L1 and the third lens L3 are both convex-concave in shape, and the second lens L2 is convex-convex in shape. As shown in fig. 1, 4 and 7, the first fixed lens group G1 uses a cemented lens group and a single lens, and the cemented surface curves toward the aperture stop STO, so that the first auxiliary light beam has a good direction and can correct spherical aberration at a high power position.

The zoom lens group G2 includes, in order, a fourth lens L4 having negative optical power, a fifth lens L5 having negative optical power, a sixth lens L6 having positive optical power, and a seventh lens L7 having negative optical power. The fifth lens element L5 and the sixth lens element L6 are cemented together to form a cemented lens group. The fourth lens L4 is convex-concave, the fifth lens L5 is concave-concave, the sixth lens L6 is convex-convex, and the seventh lens L7 is convex-concave.

The second fixed lens group G3 includes, in order, an eighth lens L8 having positive optical power, a ninth lens L9 having positive optical power, a tenth lens L10 having negative optical power, an eleventh lens L11 having negative optical power, a twelfth lens L12 having positive optical power, and a thirteenth lens L13 having negative optical power. Wherein, the eleventh lens L11 and the twelfth lens L12 or the eleventh lens L11, the twelfth lens L12 and the thirteenth lens L13 are cemented to form a cemented lens group. The eighth lens L8, the ninth lens L9, and the twelfth lens L12 are all convex-convex in shape, the tenth lens L10 and the thirteenth lens L13 are all concave-concave in shape, and the eleventh lens L11 is convex-concave in shape.

The focus lens group G4 includes, in order, a fourteenth lens L14 having positive optical power, a fifteenth lens L15 having negative optical power, and a sixteenth lens L16 having positive optical power. The fourteenth lens L14 is convex-concave, and the fifteenth lens L15 and the sixteenth lens L16 are both concave-convex.

The third fixed lens group G5 includes, in order, a seventeenth lens L17 having positive optical power and an eighteenth lens L18 having negative optical power. Among them, the seventeenth lens L17 has a concave-convex shape, and the eighteenth lens L18 has a concave-concave shape in the paraxial region. The optical power of the five lens groups is positive, negative, positive and negative in sequence, and the five lens groups are matched with different selections of the surface shapes of the lenses in each lens group for use, so that aberration is well corrected.

In the present invention, the refractive indices Nd of the eighth lens L8, the ninth lens L9, and the tenth lens L10 all satisfy the relational expressions: nd is less than or equal to 1.68. Wherein, abbe number Vb8 of the eighth lens L8 satisfies the relation: vb8 is more than or equal to 60 and less than or equal to 96. By selecting appropriate materials for the eighth lens L8, the ninth lens L9, and the tenth lens L10 of the second fixed lens group, the second-order spectral chromatic aberration can be corrected in cooperation with the power and the shape of the lens group of the present invention.

In the present invention, at least 3 of the lenses included in the zoom lens are aspheric lenses. Wherein at least 2 aspheric lenses are made of plastic material. The utility model adopts the plastic aspheric lens and the glass lens to be used in a mixed way, and can adjust the zooming function or the compensation function of the lens group, thereby realizing the light weight of the lens in the zoom lens and greatly reducing the cost. Meanwhile, the zoom lens still can image clearly in high and low temperature environments and has good performance.

In the utility model, the lenses included in the zoom lens at least comprise 3 cemented lens groups formed by cementing adjacent lenses. By adopting the cemented lens group, the chromatic aberration of the imaging part can be eliminated, the effect is good, and the infrared confocal is realized. Meanwhile, the chromatic aberration of the second-order spectrum can be further corrected by matching with the lens material.

In the utility model, the diameter phi I of the target surface covered by the zoom lens and the total length TTL of the zoom lens satisfy the relation: phi I/TTL is more than or equal to 0.070 and less than or equal to 0.110. The design can make the zoom lens small and light.

In the present invention, the absolute value of the stroke D2 of the zoom lens group G2 and the total length TTL of the zoom lens satisfy the relation: D2/TTL is more than or equal to 0.3 and less than or equal to 0.4. Meanwhile, the absolute value of the stroke D4 of the focus lens group G4 and the absolute value of the stroke D2 of the zoom lens group G2 satisfy the relationship: D4/D2 is more than or equal to 0 and less than or equal to 0.2. The zoom lens has faster zooming and focusing speed.

In summary, the present invention adopts five groups of structures, and reasonably distributes the positive and negative powers, lens surface shapes and lens materials of the lenses and lens groups, so that the aberration can be well corrected and the second-order spectral chromatic aberration can be corrected. By reasonably distributing the focal length of each lens group, the full-focus 4K high-resolution imaging can be realized. By adopting the cemented lens group, chromatic aberration and spherical aberration of the zoom lens can be eliminated or corrected, and full-focus infrared confocal is realized. By reasonably matching the temperature coefficients of the refractive indexes of the glass material and the plastic material of each lens, the zoom lens can not be defocused and images can not be distorted within the temperature range of minus 40 ℃ to 80 ℃. By using the plastic aspheric lens, small volume and low cost are realized.

The zoom lens of the present invention is specifically described below in three groups of embodiments. In the following embodiments, the image plane is denoted as IMA and the cemented surface of the cemented lens group is denoted as one side.

The parameters of each embodiment specifically satisfying the above conditional expressions are shown in table 1 below:

TABLE 1

First embodiment

Referring to fig. 1 to 3, in the present embodiment, the present invention employs a total of 18 lenses, wherein four lenses are aspheric lenses, and the seventh lens L7, the fifteenth lens L15 and the eighteenth lens L18 are all plastic aspheric lenses. Three cemented lens groups are used, as shown in fig. 1, which are cemented by a first lens L1 and a second lens L2, a fifth lens L5 and a sixth lens L6, and an eleventh lens L11, a twelfth lens L12 and a thirteenth lens L13.

In the present embodiment, the diaphragm F #: 1.6.

the parameters of each lens of the zoom lens according to the present embodiment include a surface type, a curvature radius (R value), a thickness, a refractive index of a material, and an abbe number, as shown in table 2 below:

TABLE 2

The aspheric coefficients of the aspheric lenses of the zoom lens according to the present embodiment include a conic constant K, a fourth-order aspheric coefficient a, a sixth-order aspheric coefficient B, an eighth-order aspheric coefficient C, a tenth-order aspheric coefficient D, and a twelfth-order aspheric coefficient E of the surface, as shown in table 3 below.

TABLE 3

The zoom lens according to the present embodiment has variable magnification data at the wide angle end and the telephoto end as shown in table 4 below.

	Wide angle end	Long coke end
			T1	1.8	37
T2	36.9	1.7
			T3	12.5	11
T4	0.1	1.6

TABLE 4

As can be seen from FIGS. 1 to 3, the present embodiment can realize a maximum aperture F1.6, correct the positional chromatic aberration and the magnification chromatic aberration between 380 nm and 940nm, and realize confocal imaging at 380 nm to 940 nm. Under the high-low temperature environment of minus 40 ℃ to 80 ℃, the zoom lens can still meet the full 4K resolution without refocusing. The zoom lens realizes large aperture and small volume, and is applicable to more scenes with different conditions.

Second embodiment

Referring to fig. 4 to 6, in the present embodiment, the present invention employs a total of 18 lenses, three of which are aspheric lenses, and the seventh lens L7 and the eighteenth lens L18 are both plastic aspheric lenses. Four cemented lens groups are used, as shown in fig. 4, which are cemented by a first lens L1 and a second lens L2, a fifth lens L5 and a sixth lens L6, a ninth lens L9 and a tenth lens L10, and an eleventh lens L11 and a twelfth lens L12, respectively.

In the present embodiment, F #: 1.5.

the parameters of each lens of the zoom lens according to the present embodiment include a surface type, a curvature radius (R value), a thickness, a refractive index of a material, and an abbe number, as shown in table 5 below:

TABLE 5

The aspheric coefficients of the aspheric lenses of the zoom lens according to the present embodiment include a conic constant K, a fourth-order aspheric coefficient a, a sixth-order aspheric coefficient B, an eighth-order aspheric coefficient C, a tenth-order aspheric coefficient D, and a twelfth-order aspheric coefficient E of the surface, as shown in table 6 below.

Number of noodles

K

A

B

C

D

E

S11

0

-1.55E-04

-6.12E-07

8.97E-09

-1.06E-10

1.05E-12

S12

0

-1.54E-04

-2.16E-07

1.51E-09

8.51E-11

-1.16E-12

S14

-1.34741089

1.43E-05

1.45E-09

2.26E-10

-2.18E-12

9.42E-15

S15

-6.69538182

7.80E-06

-1.39E-08

1.80E-10

-1.38E-12

1.12E-14

S32

0

-7.03E-04

9.79E-06

6.99E-08

-2.93E-09

2.86E-11

S33

0

-8.11E-04

1.02E-05

-9.94E-08

-2.29E-10

-8.43E-11

TABLE 6

The zoom lens according to the present embodiment has variable magnification data at the wide angle end and the telephoto end as shown in table 7 below.

	Wide angle end	Long coke end
			T1	1.7	37.4
T2	37.5	1.8
			T3	6.4	10.5
T4	6.3	2.2

TABLE 7

As can be seen from FIGS. 4 to 6, the present embodiment can realize a maximum aperture F1.5, correct the positional chromatic aberration and the magnification chromatic aberration between 380 nm and 940nm, and realize confocal imaging at 380 nm to 940 nm. Under the high-low temperature environment of minus 40 ℃ to 80 ℃, the zoom lens can still meet the full 4K resolution without refocusing. The zoom lens realizes large aperture and small volume, and is applicable to more scenes with different conditions.

Third embodiment

Referring to fig. 7 to 9, in the present embodiment, the present invention employs a total of 18 lenses, wherein four lenses are aspheric lenses, and the seventh lens L7, the fifteenth lens L15 and the eighteenth lens L18 are all plastic aspheric lenses. Four cemented lens groups, as shown in fig. 7, are cemented lens groups formed by a first lens L1 and a second lens L2, a fifth lens L5 and a sixth lens L6, a ninth lens L9 and a tenth lens L10, an eleventh lens L11, a twelfth lens L12, and a thirteenth lens L13, respectively.

In the present embodiment, F #: 1.4.

the parameters of each lens of the zoom lens according to the present embodiment include a surface type, a curvature radius (R value), a thickness, a refractive index of a material, and an abbe number, as shown in table 8 below:

TABLE 8

The aspheric coefficients of the aspheric lenses of the zoom lens according to the present embodiment include a conic constant K, a fourth-order aspheric coefficient a, a sixth-order aspheric coefficient B, an eighth-order aspheric coefficient C, a tenth-order aspheric coefficient D, and a twelfth-order aspheric coefficient E of the surface, as shown in table 9 below.

Number of noodles

K

A

B

C

D

E

S11

0

-1.47E-04

-5.76E-07

9.04E-09

-1.43E-10

8.69E-13

S12

0

-1.59E-04

-2.83E-07

7.86E-10

8.35E-11

-1.32E-12

S14

-1.38721332

1.39E-05

-2.00E-10

4.45E-10

-8.14E-14

1.47E-14

S15

-9.61814641

7.62E-06

-1.47E-08

-2.27E-10

-3.42E-12

-1.12E-14

S25

-2.02E-01

-8.52E-05

1.08E-06

-4.84E-08

7.75E-10

-7.50E-12

S26

-4.86E-01

-6.59E-05

1.01E-06

-2.01E-08

3.97E-10

-3.14E-12

S31

0

-5.85E-04

7.65E-06

4.40E-08

-2.61E-09

4.05E-11

S32

0

-4.49E-04

1.46E-05

-6.41E-08

3.10E-10

-6.49E-11

TABLE 9

The zoom lens according to the present embodiment has variable magnification data at the wide angle end and the telephoto end as shown in table 10 below.

	Wide angle end	Long coke end
			T1	0.5	37.1
T2	36.7	0.1
			T3	1.7	1.6
T4	9.6	9.7

Watch 10

As can be seen from FIGS. 7 to 9, the present embodiment can realize a maximum aperture F1.4, correct the positional chromatic aberration and the magnification chromatic aberration between 380 nm and 940nm, and realize confocal imaging at 380 nm to 940 nm. Under the high-low temperature environment of minus 40 ℃ to 80 ℃, the zoom lens can still meet the full 4K resolution without refocusing. The zoom lens realizes large aperture and small volume, and is applicable to more scenes with different conditions.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. 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: a first fixed lens group (G1) having positive optical power, a zoom lens group (G2) having negative optical power, an aperture Stop (STO), a second fixed lens group (G3) having positive optical power, a focus lens group (G4) having positive optical power, and a third fixed lens group (G5) arranged in order from the object side to the image side along the optical axis, the zoom lens group (G2) and the focus lens group (G4) being movable in the optical axis direction, characterized in that the optical power of the third fixed lens group (G5) is negative.

2. The zoom lens according to claim 1,

a focal length FG1 of the first fixed lens group (G1) satisfies: FG1/Fw is more than or equal to 3 and less than or equal to 5.5;

a focal length FG2 of the zoom lens group (G2) satisfies: FG2/Fw is less than or equal to-1.8 and less than or equal to-0.6;

a focal length FG3 of the second fixed lens group (G3) satisfies: FG3/Fw is more than or equal to 1 and less than or equal to 2.8;

a focal length FG4 of the focus lens group (G4) satisfies: FG4/Fw is more than or equal to 1.5 and less than or equal to 4;

a focal length FG5 of the third fixed lens group (G5) satisfies: FG5/Fw is less than or equal to-3;

where Fw is the focal length at the wide-angle end of the zoom lens.

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

the first fixed lens group (G1) includes, in order, a first lens (L1) having negative optical power, a second lens (L2) having positive optical power, and a third lens (L3) having positive optical power;

the first lens (L1) and the second lens (L2) are cemented to form a cemented lens group.

4. The zoom lens according to claim 3, 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 convex-concave;

the second lens (L2) is of a convex-convex type.

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

the zoom lens group (G2) includes, in order, a fourth lens (L4) having negative optical power, a fifth lens (L5) having negative optical power, a sixth lens (L6) having positive optical power, and a seventh lens (L7) having negative optical power;

the fifth lens (L5) and the sixth lens (L6) are cemented to form a cemented lens group.

6. The zoom lens according to claim 5, wherein, in a direction from the object side to the image side along the optical axis,

the fourth lens (L4) is of a convex-concave type;

the fifth lens (L5) is concave-concave;

the sixth lens (L6) is of convex-convex type;

the paraxial region of the seventh lens (L7) is convex-concave.

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

the second fixed lens group (G3) includes, in order, an eighth lens (L8) having positive optical power, a ninth lens (L9) having positive optical power, a tenth lens (L10) having negative optical power, an eleventh lens (L11) having negative optical power, a twelfth lens (L12) having positive optical power, and a thirteenth lens (L13) having negative optical power;

the eleventh lens (L11) and the twelfth lens (L12) or the eleventh lens (L11), the twelfth lens (L12) and the thirteenth lens (L13) are cemented to constitute a cemented lens group.

8. The zoom lens according to claim 7, wherein, in a direction from the object side to the image side along the optical axis,

the eighth lens (L8), the ninth lens (L9), and the twelfth lens (L12) are of a convex-convex type;

the tenth lens (L10) and the thirteenth lens (L13) are concave-concave;

the eleventh lens (L11) is of a convex-concave type.

9. The zoom lens according to claim 7 or 8, wherein the refractive indices Nd of the eighth lens (L8), the ninth lens (L9) and the tenth lens (L10) all satisfy the relation: nd is less than or equal to 1.68.

10. A zoom lens according to claim 9, wherein abbe number Vb8 of the eighth lens (L8) satisfies the relation: vb8 is more than or equal to 60 and less than or equal to 96.

11. The zoom lens according to claim 1, wherein the focus lens group (G4) includes, in order from the object side to the image side along the optical axis, a fourteenth lens (L14) having positive optical power, a fifteenth lens (L15) having negative optical power, and a sixteenth lens (L16) having positive optical power.

12. The zoom lens according to claim 11, wherein, in a direction from the object side to the image side along the optical axis,

the fourteenth lens (L14) is convex-concave;

the fifteenth lens (L15) and the sixteenth lens (L16) are of a concave-convex type.

13. The zoom lens according to claim 1, wherein the third fixed lens group (G5) includes, in order in a direction from the object side to the image side along the optical axis, a seventeenth lens (L17) having positive optical power and an eighteenth lens (L18) having negative optical power.

14. The zoom lens according to claim 13, wherein, in a direction from the object side to the image side along the optical axis,

the seventeenth lens (L17) is of a concave-convex type;

the paraxial region of the eighteenth lens (L18) is concave-concave.

15. The zoom lens according to any one of claims 1 to 8 and 10 to 14, wherein at least 3 of the lenses included in the zoom lens are aspheric lenses; wherein at least 2 of the aspheric lenses are made of plastic material.

16. The zoom lens according to claim 9, wherein at least 3 of the lenses included in the zoom lens are aspheric lenses; wherein at least 2 of the aspheric lenses are made of plastic material.

17. A zoom lens according to any one of claims 1 to 8 and 10 to 14, wherein the zoom lens comprises at least 3 cemented lens groups of adjacent lenses.

18. The zoom lens according to claim 9, wherein the zoom lens comprises at least 3 cemented lens groups of adjacent lenses.

19. A zoom lens according to any one of claims 1 to 8, 10 to 14, 16 or 18, wherein the diameter (Φ I) of the target surface covered by the zoom lens and The Total Length (TTL) of the zoom lens satisfy the relation: phi I/TTL is more than or equal to 0.070 and less than or equal to 0.110.

20. The zoom lens according to claim 9, wherein the diameter (Φ I) of the target surface covered by the zoom lens and The Total Length (TTL) of the zoom lens satisfy the relationship: phi I/TTL is more than or equal to 0.070 and less than or equal to 0.110.

21. The zoom lens according to claim 15, wherein the diameter (Φ I) of the target surface covered by the zoom lens and The Total Length (TTL) of the zoom lens satisfy the relationship: phi I/TTL is more than or equal to 0.070 and less than or equal to 0.110.

22. The zoom lens according to claim 17, wherein the diameter (Φ I) of the target surface covered by the zoom lens and The Total Length (TTL) of the zoom lens satisfy the relationship: phi I/TTL is more than or equal to 0.070 and less than or equal to 0.110.

23. A zoom lens according to any one of claims 1, 5 or 6, wherein the absolute value of the stroke (D2) of the zoom lens group (G2) and The Total Length (TTL) of the zoom lens satisfy the relation: D2/TTL is more than or equal to 0.3 and less than or equal to 0.4.

24. A zoom lens according to any one of claims 1, 5, 6, 11 or 12, wherein the absolute value of stroke (D4) of the focus lens group (G4) and the absolute value of stroke (D2) of the zoom lens group (G2) satisfy the relationship: D4/D2 is more than or equal to 0 and less than or equal to 0.2.