CN113805322A

CN113805322A - Zoom lens

Info

Publication number: CN113805322A
Application number: CN202111158946.7A
Authority: CN
Inventors: 陈汇东; 陈瑶; 白兴安; 罗荣彬
Original assignee: Sunny Optics Zhongshan Co Ltd
Current assignee: Sunny Optics Zhongshan Co Ltd
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2021-12-17

Abstract

The invention 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 with positive focal power, 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, and the focusing lens group consists of 3 lenses. On the premise that the zoom ratio of the zoom lens and the front end caliber and the total length of the lens are in a mutual restriction relationship, the zoom lens still can realize large-angle, small-volume and low-distortion, and can realize high-resolution and full-focus 4K imaging in the whole zoom stroke.

Description

Zoom lens

Technical Field

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

Background

The telephoto end resolution of the existing large-magnification zoom lens is mostly on the level of 2M and 4M, the zoom ratio of the zoom lens and the front end caliber and the total length of the lens have a mutual restriction relationship, the miniaturization is difficult to realize, and the large angle and the low distortion are difficult to realize simultaneously. In addition, it is difficult to reduce the cost by using a glass aspherical surface to ensure lens resolution.

Chinese patent CN112305731A discloses a zoom lens. The lens comprises 18 lenses in total, and the design of a five-group framework is adopted, so that the performance requirements of high magnification, large aperture and large target surface are met, and the full-focus 4K imaging is realized. However, this lens does not solve the problem that miniaturization is difficult due to the mutual restriction between the zoom ratio of the zoom lens and the tip diameter and the total length of the lens.

Disclosure of Invention

In order to overcome the above drawbacks, an object of the present invention is to provide a zoom lens that has a small size and high resolution and is capable of preventing image distortion at high and low temperatures.

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 focus lens group consists of 3 lenses.

According to one aspect of the invention, the focal length FG1 of the first fixed lens group satisfies: FG1/FW is more than or equal to 1.4 and less than or equal to 3.6;

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

According to one aspect of the invention, the focal length FG2 of the zoom lens group satisfies: FG2/FW is not less than-1.5 and not more than-0.5.

According to one aspect of the invention, the focal length FG3 of the second fixed lens group satisfies: FG3/FW is more than or equal to 1.1 and less than or equal to 2.6.

According to one aspect of the invention, the focal length FG4 of the focus lens group satisfies: FG4/FW is more than or equal to 1.3 and less than or equal to 3.8.

According to one aspect of the invention, the focal length FG5 of the third fixed lens group satisfies: FG5/FW is more than or equal to 7.3 and less than or equal to 14.1.

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 third lens are both convex-concave lenses, and the second lens is a convex-convex lens;

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

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;

the fourth lens is a convex-concave lens, the fifth lens is a concave-concave lens, the sixth lens is a convex-convex lens, and the seventh lens is a concave-convex lens;

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

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 positive or negative focal power and an eleventh lens with positive or negative focal power;

the eighth lens is a convex-concave lens, and the ninth lens is a convex-convex lens.

the focusing lens group sequentially comprises a twelfth lens with positive focal power, a thirteenth lens with positive focal power and a fourteenth lens with negative focal power;

the twelfth lens and the thirteenth lens are both convex and convex lenses, and the fourteenth lens is a concave and concave lens;

and the thirteenth lens and the fourteenth lens are cemented to form a cemented lens group.

the third fixed lens group includes, in order, a fifteenth lens having positive or negative optical power and a sixteenth lens having positive or negative optical power.

According to an aspect of the present invention, among the lenses included in the zoom lens group, the second fixed lens group, and the third fixed lens group, there are at least 3 plastic aspheric lenses.

According to an aspect of the present invention, a stroke D2 of the zoom lens group and a total length TTL of the zoom lens satisfy the relation: D2/TTL is more than or equal to 0.14 and less than or equal to 0.28.

According to an aspect of the present invention, the stroke D4 of the focus lens group and the stroke D2 of the zoom lens group satisfy the relation: the absolute value of D4/D2 is less than or equal to 0.35 and less than or equal to 0.50.

According to an aspect of the invention, an abbe number Vb4 of the fourth lens satisfies the relation: 15 is less than or equal to Vb4 is less than or equal to 30.

According to one aspect of the invention, the focal length FG2 of the zoom lens group and the focal length FG4 of the focus lens group satisfy the relationship: FG2/FG4 is less than or equal to-0.50 and less than or equal to-0.30.

According to an aspect of the present invention, the maximum lens diameter Φ G1 of the first fixed group and the total length TTL of the zoom lens satisfy the relation: phi G1/TTL is more than or equal to 0.20 and less than or equal to 0.40.

According to one aspect of the invention, the lens has at least 3 cemented lens groups.

According to the scheme of the invention, the zoom lens applicable to the video conference is provided. The lens can realize wide angle, low distortion and small volume, can realize high resolution in the whole zoom stroke, can realize 4K imaging of a full focal length, can clearly highlight target characters and objects, ensures the definition and the perfect details of images, and is real and restored. The lens can be suitable for video real-time interaction and can be widely applied to various scenes such as education, medical treatment, government institutions and the like.

According to one scheme of the invention, a five-group structure with the focal power of positive-negative-positive is adopted, and the five-group structure is composed of a first fixed lens group, a zoom lens group, a second fixed lens group, a focusing lens group and a third fixed lens group, so that the contradiction between the relationship that the zoom ratio and the front end aperture and the total length of a lens are mutually restricted and the miniaturization, large angle and low distortion of the lens are solved, the short focal length and the prominent depth of field can be realized, the performance requirements of large angle, small volume and low distortion are met, and the full-focus 4K imaging can be realized.

According to one aspect of the present invention, the difference between the thermal properties of the optical materials is utilized to eliminate the temperature effect on the performance of the optical system over a wide temperature range of-40 ℃ to 80 ℃ by reasonable power distribution and selection of specific glass materials, thereby maintaining stable image quality without virtual focus. The imaging of 4K resolution ratio is satisfied in the full focus section, and the image quality is stable and high-definition.

According to one aspect of the present invention, a lens using a plastic aspherical material is used in a rational manner, thereby reducing the cost of the zoom lens.

According to one scheme of the invention, the action of the zoom lens group and the focusing lens group is adjusted, so that the proportion of the stroke of the zoom lens group in the total length of the lens and the stroke proportion of the focusing lens group and the zoom lens group respectively meet a certain range, and the zoom lens can quickly respond to the zooming-focusing function. The image is fine and smooth while having good automatic focusing and quick zooming functions.

According to one scheme of the invention, the maximum lens diameter in the first fixed group is adjusted and the ratio of the maximum lens diameter to the total lens length is within a certain range, so that the size of the lens can be small, and the practical application requirements can be met.

According to one aspect of the invention, the chromatic aberration of the system can be corrected by reasonably using and adjusting the dispersion coefficient of the lens in the zoom lens.

According to one aspect of the present invention, the tolerance sensitivities of the zoom group, the focus group, and the entire optical system of the lens can be adjusted by reasonably setting and adjusting the focal length ranges of the zoom lens group and the focus lens group.

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 view schematically showing a defocus curve of the zoom lens according to the first embodiment of the present invention at a wide angle end-40 ℃;

FIG. 5 schematically shows a defocus curve of a zoom lens according to the first embodiment of the present invention at a wide-angle end of 80 ℃;

FIG. 6 is a view schematically showing a defocus curve of a zoom lens according to the first embodiment of the present invention at a telephoto end-40 ℃;

FIG. 7 is a view schematically showing a defocus curve of a zoom lens according to the first embodiment of the present invention at a telephoto end of 80 ℃;

FIG. 8 is a schematic view showing a configuration of a zoom lens according to a second embodiment of the present invention;

FIG. 9 schematically shows an MTF chart at the wide-angle end of a zoom lens according to a second embodiment of the present invention;

FIG. 10 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. 11 is a view schematically showing a defocus curve of a zoom lens according to a second embodiment of the present invention at a wide angle end-40 ℃;

FIG. 12 is a view schematically showing a defocus curve of a zoom lens according to a second embodiment of the present invention at a wide angle end of 80 ℃;

FIG. 13 is a view schematically showing a defocus curve of a zoom lens according to a second embodiment of the present invention at a telephoto end-40 ℃;

FIG. 14 is a view schematically showing a defocus graph at 80 ℃ at the telephoto end in a zoom lens according to a second embodiment of the present invention;

FIG. 15 is a schematic view showing a configuration of a zoom lens according to a third embodiment of the present invention;

FIG. 16 schematically shows an MTF chart at the wide-angle end of a zoom lens according to a third embodiment of the present invention;

FIG. 17 is a schematic view showing an MTF chart at the telephoto end in a zoom lens according to a third embodiment of the present invention;

FIG. 18 is a view schematically showing a defocus curve of a zoom lens according to a third embodiment of the present invention at a wide angle end-40 ℃;

FIG. 19 schematically shows a defocus curve of a zoom lens according to a third embodiment of the present invention at a wide angle end of 80 ℃;

FIG. 20 is a view schematically showing a defocus curve of a zoom lens according to a third embodiment of the present invention at a telephoto end-40 ℃;

FIG. 21 is a schematic view showing a defocus curve of a zoom lens according to a third embodiment of the present invention at a telephoto end of 80 ℃.

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 invention, 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 positive optical power. The focusing lens group G4 is composed of 3 lenses, which are the twelfth lens L12, the thirteenth lens L13 and the fourteenth lens L14 shown in fig. 1. The five-group structure includes 16 lenses in total. The focal power of the first fixed lens group G1 is positive, and the focal power of the zoom lens group G2 is negative, thereby achieving a large angle and a large zoom magnification. The zoom lens group G2 is movable in the optical axis direction for optical zooming of the zoom lens between the wide-angle end and the telephoto end. The focus lens group G4 is also movable in the optical axis direction for compensating for the change in the image plane position during optical zooming.

Through the arrangement, five lens groups with positive, negative, positive and positive focal powers are adopted, the contradiction between the relationship of mutual restriction between the zoom ratio and the front end caliber and the total length of the lens and the miniaturization, large angle and low distortion of the lens is solved, the short focal length and the outstanding depth of field can be realized, and the performance requirements of large angle, small volume and low distortion are met.

In the present invention, the focal length FG1 of the first fixed lens group G1 satisfies: FG1/FW is more than or equal to 1.4 and less than or equal to 3.6; the focal length FG2 of the zoom lens group G2 satisfies: FG2/FW is not less than 1.5 and not more than-0.5; the focal length FG3 of the second fixed lens group G3 satisfies: FG3/FW is more than or equal to 1.1 and less than or equal to 2.6; the focal length FG4 of the focus lens group G4 satisfies: FG4/FW is more than or equal to 1.3 and less than or equal to 3.8; the focal length FG5 of the third fixed lens group G5 satisfies: FG5/FW is more than or equal to 7.3 and less than or equal to 14.1. Where FW is the focal length at the wide-angle end of the zoom lens. By adopting five lens groups with the focal powers of positive, negative, positive and positive in sequence, and setting the ratio range between the focal length of each lens group and the focal length of the wide angle end of the zoom lens, when the zoom lens group G2 moves on the optical axis to realize zooming, the focusing lens group G4 can compensate aberration through the movement on the optical axis, so that the aberration is well corrected, and 4K imaging of a full focus segment is realized.

In the present invention, the first fixed lens group G1 includes, in order along the optical axis from the object side to the image side, 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 third lens L3 are convex-concave lenses, and the second lens L2 is a convex-convex lens. 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 fourth lens L4 is a convex-concave lens, the fifth lens L5 is a concave-concave lens, the sixth lens L6 is a convex-convex lens, and the seventh lens L7 is a concave-convex lens. 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 positive or negative optical power, and an eleventh lens L11 having positive or negative optical power; the eighth lens L8 is a convex-concave lens, and the ninth lens L9 is a convex-convex lens. The focus lens group G4 includes, in order, a twelfth lens L12 having positive optical power, a thirteenth lens L13 having positive optical power, and a fourteenth lens L14 having negative optical power; the twelfth lens L12 and the thirteenth lens L13 are both convex and convex lenses, and the fourteenth lens L14 is a concave and concave lens. The third fixed lens group G5 includes, in order, a fifteenth lens L15 having positive or negative optical power and a sixteenth lens L16 having positive or negative optical power.

The first lens L1 and the second lens L2 are cemented together to form a cemented lens group, the fifth lens L5 and the sixth lens L6 are cemented together to form a cemented lens group, and the thirteenth lens L13 and the fourteenth lens L14 are also cemented together to form a cemented lens group. The lens has at least 3 cemented lens groups. As shown in fig. 1, the first fixed lens group G1 uses a cemented lens group and a single lens in combination, and the cemented surface is curved toward the aperture stop STO, so that the first auxiliary light has a good direction and spherical aberration at high power position can be corrected. By adopting the cemented lens group, the chromatic aberration of the imaging part can be eliminated, and the effect is good.

In the present invention, among the lenses included in the zoom lens group G2, the second fixed lens group G3, and the third fixed lens group G5, at least 3 plastic aspherical lenses are included, and the remaining lenses are glass spherical lenses. Through the selection and reasonable distribution of specific glass materials, the difference between the thermal characteristics of the optical materials is utilized and is matched with the setting of the focal power, and the influence of the temperature on the performance of an optical system is eliminated in a large temperature range of-40-80 ℃, so that the stability of the image quality is kept, virtual focus is avoided, imaging with 4K resolution in a full focus section is met, and the image quality is stable and high-definition. In addition, through mixing the lens made of the plastic material, the zooming function or the compensation function of the lens group can be adjusted, so that the light weight of the zoom lens is realized, and the cost is greatly reduced. The at least three cemented lens groups are matched with the lens materials, so that the secondary spectral chromatic aberration of the zoom lens can be further corrected.

In the present invention, the stroke D2 of the zoom lens group G2 and the total length TTL of the zoom lens satisfy the relationship: D2/TTL is more than or equal to 0.14 and less than or equal to 0.28. The stroke D4 of the focus lens group G4 and the stroke D2 of the zoom lens group G2 satisfy the relationship: the absolute value of D4/D2 is less than or equal to 0.35 and less than or equal to 0.50. By adjusting the actions of the zoom lens group and the focusing lens group, the stroke proportion of the zoom lens group in the lens and the stroke proportion of the focusing lens group and the zoom lens group are changed, so that the zoom lens can quickly respond to the zooming-focusing function.

In the present invention, abbe number Vb4 of fourth lens L4 satisfies the relation: 15 is less than or equal to Vb4 is less than or equal to 30. The chromatic aberration of the lens can be corrected by reasonably using and adjusting the dispersion coefficient of the lens.

In the present invention, the focal length FG2 of the zoom lens group G2 and the focal length FG4 of the focus lens group G4 satisfy the relationship: FG2/FG4 is less than or equal to-0.50 and less than or equal to-0.30. The tolerance sensitivity of the zoom group, the focusing group and the whole optical system of the adjustable zoom lens is designed in this way.

In the present invention, the maximum lens diameter Φ G1 of the first fixed group G1 and the total length TTL of the zoom lens satisfy the relation: phi G1/TTL is more than or equal to 0.20 and less than or equal to 0.40. The diameter of the maximum lens in the first fixed group is adjusted to be within a certain range in the total length of the lens, so that the zoom lens can ensure small volume while the zoom ratio of the lens and the front end caliber and the total length of the lens are mutually restricted, the real-time interactive practical application requirement of video signals is met, and the zoom lens can be widely applied to various scenes such as education, medical treatment, government agencies and the like.

In summary, the present invention adopts five groups of structures with focal powers of "positive-negative-positive", which include 16 lenses in total, to realize large angle and low distortion. Moreover, the reasonable arrangement of the cemented lens group and the reasonable distribution of lens materials can correct the secondary spectral chromatic aberration while the aberration is well corrected. The full-focus 4K high-resolution imaging is realized by reasonably distributing the focal lengths of all the lens groups. By reasonably matching and using the lenses made of glass and plastic materials, the influence of temperature on the performance of an optical system can be eliminated within a larger temperature range of minus 40 ℃ to 80 ℃, so that the stability of image quality is kept, virtual focus is avoided, the light weight and small volume of the lens can be realized, and the cost is effectively reduced.

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

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

TABLE 1

In the invention, the aspheric lens of the zoom lens meets the following formula:

in the above formula, z is the axial distance from the curved surface to the vertex at the position of the height h perpendicular to the optical axis along the optical axis direction; c. CRepresenting the curvature at the apex of the aspheric surface; k is a conic coefficient; a. the₄、A₆、A₈、A₁₀、A₁₂、A₁₄、A₁₆The aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth and sixteenth orders are expressed respectively.

First embodiment

Referring to fig. 1 to 7, in the present embodiment, the zoom lens employs 16 lenses in total, and among them, there are 3 plastic aspheric lenses. As shown in fig. 1, the 4 cemented lens groups are respectively formed by a first lens L1, a second lens L2, a fifth lens L5, a sixth lens L6, a tenth lens L10, an eleventh lens L11, a thirteenth lens L13 and a fourteenth lens L14 by cementing.

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.

Number of noodles

K

A

B

C

D

E

S11

1.539331

-1.002E-004

2.3482E-005

-8.230E-007

3.7804E-008

-1.861E-009

S12

-30.030907

-3.912E-004

1.3023E-005

-2.693E-007

-1.403E-008

6.9158E-010

S14

0.749365

-7.066E-005

2.5207E-006

-8.561E-008

8.7377E-009

3.9594E-010

S15

25.517627

1.5455E-004

3.8363E-006

-9.776E-008

9.9321E-009

2.2465E-010

S28

-26.947966

-4.671E-003

2.6670E-004

-1.133E-005

1.8127E-007

-2.037E-008

S29

1.823440

-5.570E-003

2.6779E-004

-2.089E-005

5.7053E-007

-5.899E-008

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	Telescope end
			T1	0.52	9.97
T2	9.86	0.41
			T3	5.25	2.94
T4	1.57	3.88

TABLE 4

As can be seen from fig. 1 to 7, the above arrangement of the present embodiment can correct the positional chromatic aberration and the chromatic aberration of magnification between 420 nm and 680nm, and the purple fringing is small. Through the reasonable construction of an optical framework, the plastic aspheric lens is used, the focal powers of different lenses are reasonably distributed, the wide-angle, low-distortion and miniaturized performances are realized, and the 4K clear imaging of a full-focus section is ensured.

Second embodiment

Referring to fig. 8 to 14, in the present embodiment, the zoom lens employs 16 lenses in total, and there are 4 plastic aspheric lenses. As shown in fig. 8, the 3 cemented lens groups are cemented lens groups formed by a first lens L1, a second lens L2, a fifth lens L5, a sixth lens L6, a thirteenth lens L13 and a fourteenth lens L14.

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

3.097128

-1.957E-004

1.1335E-005

-1.502E-006

7.2183E-008

1.8880E-008

S12

97.162591

-3.272E-004

2.0504E-005

-1.760E-008

-8.598E-008

-2.399E-008

S14

0.617139

-1.183E-004

2.1026E-006

-7.797E-008

9.3170E-009

4.1979E-010

S15

25.516279

2.0317E-004

4.6802E-006

-8.465E-008

1.0445E-008

2.6057E-010

S27

20.788245

3.0562E-004

1.1465E-005

4.849E-008

-7.8461E-008

-5.8462E-010

S28

16.785549

1.8524E-004

2.1482E-005

2.965E-008

-8.4715E-008

-6.7428E-010

S29

28.728346

-4.219E-003

3.7576E-004

-7.832E-006

9.9542E-008

-5.310E-008

S30

-30.713394

-6.000E-003

2.2489E-004

-2.040E-005

8.0573E-007

-2.992E-008

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 angleTerminal end	Telescope end
			T1	0.44	9.59
T2	9.74	0.59
			T3	5.34	2.85
T4	1.66	4.15

TABLE 7

As can be seen from fig. 8 to 14, the above arrangement of the present embodiment can correct the positional chromatic aberration and the chromatic aberration of magnification between 420 nm and 680nm, has a small purple fringe, and can satisfy the resolution of the full focus range of 4K. By arranging lens combinations with different structures and reasonably distributing the focal power of each lens, the vignetting is reduced or not arranged, and the low distortion and the high relative illumination of the zoom lens are realized while high resolution is obtained.

Third embodiment

Referring to fig. 15 to 21, in the present embodiment, the zoom lens employs 16 lenses in total, and among them, there are 3 plastic aspheric lenses. As shown in fig. 15, the 3 cemented lens groups are cemented by a first lens L1, a second lens L2, a fifth lens L5, a sixth lens L6, a thirteenth lens L13 and a fourteenth lens L14.

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.

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	Telescope end
			T1	0.68	9.64
T2	9.53	0.57
			T3	5.42	2.56
T4	1.51	4.37

Watch 10

As can be seen from fig. 15 to 21, the above arrangement of the present embodiment can correct the positional chromatic aberration and the chromatic aberration of magnification between 420 nm and 680nm, has a small purple fringe, and satisfies the resolution of the full focus range of 4K. The focal power is reasonably distributed, so that aberrations such as spherical aberration, field curvature and the like can be well corrected, and the resolution of the zoom lens is improved.

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) with positive focal power, a zoom lens group (G2) with negative focal power, an aperture Stop (STO), a second fixed lens group (G3) with positive focal power, a focusing lens group (G4) with positive focal power and a third fixed lens group (G5) with positive focal power, which are arranged in sequence from the object side to the image side along the optical axis, wherein the zoom lens group (G2) and the focusing lens group (G4) can move along the optical axis direction, and the focusing lens group (G4) is composed of 3 lenses.

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 1.4 and less than or equal to 3.6;

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

3. The zoom lens according to claim 1,

a focal length (FG2) of the zoom lens group (G2) satisfies: FG2/FW is not less than-1.5 and not more than-0.5.

4. The zoom lens according to claim 1,

a focal length (FG3) of the second fixed lens group (G3) satisfies: FG3/FW is more than or equal to 1.1 and less than or equal to 2.6.

5. The zoom lens according to claim 1,

a focal length (FG4) of the focus lens group (G4) satisfies: FG4/FW is more than or equal to 1.3 and less than or equal to 3.8.

6. The zoom lens according to claim 1,

a focal length (FG5) of the third fixed lens group (G5) satisfies: FG5/FW is more than or equal to 7.3 and less than or equal to 14.1.

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 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 third lens (L3) are both convex-concave lenses, and the second lens (L2) is a convex-convex lens;

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

8. 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 fourth lens (L4) is a convex-concave lens, the fifth lens (L5) is a concave-concave lens, the sixth lens (L6) is a convex-convex lens, and the seventh lens (L7) is a concave-convex lens;

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

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 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 positive or negative optical power, and an eleventh lens (L11) having positive or negative optical power;

the eighth lens (L8) is a convex-concave lens, and the ninth lens (L9) is a convex-convex lens.

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

the focusing lens group (G4) includes, in order, a twelfth lens (L12) having positive optical power, a thirteenth lens (L13) having positive optical power, and a fourteenth lens (L14) having negative optical power;

the twelfth lens (L12) and the thirteenth lens (L13) are both convex-convex lenses, and the fourteenth lens (L14) is a concave-concave lens;

the thirteenth lens (L13) and the fourteenth lens (L14) are cemented to form a cemented lens group.