阅读说明：本技术 一种变焦镜头和成像装置 (Zoom lens and imaging device ) 是由 袁浩生 周洁 沈峰 于 2021-08-23 设计创作，主要内容包括：本发明涉及光学领域,具体为一种变焦镜头和成像装置。所述变焦镜头从物面侧到像面侧依次包括：正光焦度的第一透镜群,负光焦度的第二透镜群,正光焦度的第三透镜群,负光焦度的第四透镜群和正光焦度的第五透镜群；所述第二透镜群和所述第四透镜群沿所述变焦镜头的主光轴方向移动；TTL＜100mm；2＜ft/fw＜3；1.2＜fno＜1.3；其中,TTL为所述变焦镜头的光学总长,ft为所述变焦镜头在望远状态的焦距,fw为所述变焦镜头在广角状态的焦距,fno为所述变焦镜头的光圈数。变焦镜头的通光量较大,增加了变焦镜头在低照环境下的效果,增加了变焦镜头的成像质量。(The invention relates to the field of optics, in particular to a zoom lens and an imaging device. The zoom lens sequentially comprises from an object plane side to an image plane side: the lens comprises a first lens group with positive focal power, a second lens group with negative focal power, a third lens group with positive focal power, a fourth lens group with negative focal power and a fifth lens group with positive focal power; the second lens group and the fourth lens group move along the main optical axis direction of the zoom lens; TTL is less than 100 mm; 2 < ft/fw < 3; fno is more than 1.2 and less than 1.3; wherein, TTL is the total optical length of the zoom lens, ft is the focal length of the zoom lens in the telephoto state, fw is the focal length of the zoom lens in the wide angle state, and fno is the f-number of the zoom lens. The light-passing amount of the zoom lens is large, the effect of the zoom lens in a low-light environment is improved, and the imaging quality of the zoom lens is improved.)

1. A zoom lens, comprising, in order from an object plane side to an image plane side:

the lens comprises a first lens group with positive focal power, a second lens group with negative focal power, a third lens group with positive focal power, a fourth lens group with negative focal power and a fifth lens group with positive focal power;

the second lens group and the fourth lens group move along the main optical axis direction of the zoom lens;

TTL＜100mm；

2＜ft/fw＜3；

1.2＜fno＜1.3；

wherein, TTL is the total optical length of the zoom lens, ft is the focal length of the zoom lens in the telephoto state, fw is the focal length of the zoom lens in the wide angle state, and fno is the f-number of the zoom lens.

2. A zoom lens according to claim 1, wherein:

the first lens group includes, in order from an object plane side to an image plane side:

the lens comprises a first lens with positive focal power, a second lens with positive focal power and a third lens with negative focal power.

3. A zoom lens according to claim 1, wherein:

the second lens group includes, in order from the object plane side to the image plane side:

a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with positive focal power.

4. A zoom lens according to claim 1, wherein:

the third lens group at least comprises three lenses with positive focal power.

5. The zoom lens according to claim 4, wherein:

the third lens group includes, in order from the object plane side to the image plane side:

the optical lens system comprises a seventh lens with positive focal power, an eighth lens with positive focal power, a ninth lens with negative focal power and a tenth lens with positive focal power, wherein the ninth lens and the tenth lens are cemented.

6. A zoom lens according to claim 1, wherein:

the fifth lens group includes, in order from the object plane side to the image plane side:

a twelfth lens of positive power and a thirteenth lens of negative power.

7. A zoom lens according to claim 2, wherein:

the first lens group satisfies the following conditional expression:

0.55＜|(R21+R12)/(R21-R12)|＜0.7；

wherein R12 is the curvature radius of the curved surface of the first lens close to the image surface, and R21 is the curvature radius of the curved surface of the second lens close to the object surface.

8. A zoom lens according to claim 1, wherein:

the zoom lens satisfies the following conditional expression:

IH/fw＞0.8；

wherein IH is the image height of the zoom lens.

9. A zoom lens according to claim 1, wherein:

the zoom lens satisfies the following conditional expression:

0.05＜S4/S2＜0.2；

wherein S4 is a moving distance of the fourth lens group, and S2 is a moving distance of the second lens group.

10. A zoom lens according to claim 1, wherein:

the zoom lens satisfies the following conditional expression:

1.15＜fg3/fw＜1.25；

wherein fg3 is a focal length of the third lens group.

11. A zoom lens according to claim 3, wherein:

the second lens group satisfies the following conditional expression:

25＜|R41/R42|＜35；

wherein R41 is a radius of curvature of the fourth lens surface-near-object-side curved surface, and R42 is a radius of curvature of the fourth lens surface-near-image-surface-side curved surface.

12. A zoom lens according to claim 3, wherein:

the second lens group satisfies the following conditional expression:

1≤R52/R61＜1.2；

wherein, R52 is a curvature radius of the curved surface of the fifth lens on the side close to the image plane, and R61 is a curvature radius of the curved surface of the sixth lens on the side close to the object plane.

13. A zoom lens according to claim 6, wherein:

the fourth lens group is an eleventh lens with negative focal power.

14. A zoom lens according to claim 13, wherein:

a curved surface of the thirteenth lens element on the object plane side and a curved surface of the twelfth lens element on the image plane side are both curved toward the image plane side;

and/or;

the curved surface of the eleventh lens on the image plane side and the curved surface of the twelfth lens on the object plane side are both curved toward the object plane side.

15. An image forming apparatus comprising:

a zoom lens according to any one of claims 1 to 14;

and an imaging element configured to receive an image formed by the zoom lens.

Technical Field

The invention relates to the field of optics, in particular to a zoom lens and an imaging device.

Background

Machine vision refers to the use of machines to replace human eyes for recognition and judgment. Machine vision refers to the conversion of an object to be detected into image signals by imaging the object onto an image pickup device through a lens, and then various operations are performed on the signals by an image processing system, thereby achieving various functions.

At present, a 2-3X zoom lens with a long focal length of about 45mm in the market generally has a small aperture, and the image quality acquired by the image pickup device is low in a low-light environment.

Disclosure of Invention

The zoom lens and the imaging device solve the technical problems in the prior art, the light flux of the zoom lens is large, the effect of the zoom lens in a low-light environment is improved, and the imaging quality of the zoom lens is improved.

The technical scheme provided by the invention is as follows:

a zoom lens comprising, in order from an object plane side to an image plane side:

the lens comprises a first lens group with positive focal power, a second lens group with negative focal power, a third lens group with positive focal power, a fourth lens group with negative focal power and a fifth lens group with positive focal power;

the second lens group and the fourth lens group move along the main optical axis direction of the zoom lens;

TTL＜100mm；

2＜ft/fw＜3；

1.2＜fno＜1.3；

wherein, TTL is the total optical length of the zoom lens, ft is the focal length of the zoom lens in the telephoto state, fw is the focal length of the zoom lens in the wide angle state, and fno is the f-number of the zoom lens.

According to the technical scheme, through the arrangement of the structure, the focal length of the far-end of the zoom lens is moderate, the total volume of the zoom lens is small, but the light flux of the zoom lens is large, the effect of the zoom lens in a low-light environment is improved, and the imaging quality of the zoom lens is improved.

Preferably, the first lens group includes, in order from an object plane side to an image plane side:

the lens comprises a first lens with positive focal power, a second lens with positive focal power and a third lens with negative focal power.

Preferably, the second lens group includes, in order from the object plane side to the image plane side:

a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with positive focal power.

Preferably, the third lens group includes at least three lenses with positive focal power.

In the technical scheme, through the arrangement of the three lenses with positive focal powers, light rays are rapidly converged within a limited distance, the value of the relative aperture is increased under the condition of a certain length, the possibility of overlarge focal power of a certain lens in the third lens group is reduced, and the possibility of overlarge lens thickness is reduced.

Preferably, the third lens group includes, in order from the object plane side to the image plane side:

the optical lens system comprises a seventh lens with positive focal power, an eighth lens with positive focal power, a ninth lens with negative focal power and a tenth lens with positive focal power, wherein the ninth lens and the tenth lens are cemented.

Preferably, the fifth lens group includes, in order from the object plane side to the image plane side:

a twelfth lens of positive power and a thirteenth lens of negative power.

Preferably, the first lens group satisfies the following conditional expression:

0.55＜|(R21+R12)/(R21-R12)|＜0.7；

wherein R12 is the curvature radius of the curved surface of the first lens close to the image surface, and R21 is the curvature radius of the curved surface of the second lens close to the object surface.

In the technical scheme, the curvature radius of the two opposite side curved surfaces of the first lens and the second lens is limited, so that light rays are converged to a certain degree at the first fixed group under the condition that the integral focal power of the first fixed group is not changed, the entrance pupil is enlarged under the condition that the size of the aperture is not changed, and the brightness of the zoom lens is increased.

Preferably, the zoom lens satisfies the following conditional expression:

IH/fw＞0.8；

wherein IH is the image height of the zoom lens.

In the technical scheme, the size of the sensor suitable for the zoom lens is increased by limiting the height of the zoom lens image, and then the imaging quality of the zoom lens is increased.

Preferably, the zoom lens satisfies the following conditional expression:

0.05＜S4/S2＜0.2；

wherein S4 is a moving distance of the fourth lens group, and S2 is a moving distance of the second lens group.

In the technical scheme, the moving distance of the fourth lens group and the second lens group is limited, so that the zooming range of the zoom lens with small magnification is realized, the possibility of changing the aperture is reduced, and the effect of keeping the aperture constant is realized.

1 preferably, the zoom lens satisfies the following conditional expression:

1.15＜fg3/fw＜1.25；

wherein fg3 is a focal length of the third lens group.

In the technical scheme, the focal length of the third lens group is limited, so that the reasonable distribution of the focal lengths of the lenses in the zoom lens is effectively realized, the possibility that the focal lengths of other lens groups are too large or too small is reduced, and the miniaturization of the zoom lens is realized.

Preferably, the second lens group satisfies the following conditional expression:

25＜|R41/R42|＜35；

wherein R41 is a radius of curvature of the fourth lens surface-near-object-side curved surface, and R42 is a radius of curvature of the fourth lens surface-near-image-surface-side curved surface.

In the technical scheme, the curvature radius of the curved surfaces at two sides of the fourth lens group is limited, so that the surface of the fourth lens facing the image side has a larger curvature radius, and the fourth lens is relatively insensitive to installation errors; the curvature radius of the surface of the fourth lens facing the object side is relatively small, so that light rays can be diffused, the clear aperture at the diaphragm is large, and distortion can be controlled.

Preferably, the second lens group satisfies the following conditional expression:

1≤R52/R61＜1.2；

wherein, R52 is a curvature radius of the curved surface of the fifth lens on the side close to the image plane, and R61 is a curvature radius of the curved surface of the sixth lens on the side close to the object plane.

In the technical scheme, the improvement of the chromatic aberration and distortion of light is realized and the imaging quality of the zoom lens is improved by limiting the curvature radius of the fifth lens and the curvature radius of the sixth lens.

Preferably, the fourth lens group is an eleventh lens with negative focal power.

Preferably, a curved surface of the thirteenth lens closer to the object plane and a curved surface of the twelfth lens closer to the image plane are both curved toward the image plane;

and/or;

the curved surface of the eleventh lens on the image plane side and the curved surface of the twelfth lens on the object plane side are both curved toward the object plane side.

In the technical scheme, the direction of the curved surfaces of the eleventh lens and the thirteenth lens is limited, so that the trend of light rays is effectively controlled, a larger target surface is realized, chromatic aberration and aberration of the zoom lens are reduced, and the imaging quality of the zoom lens is improved.

It is also an object of the present invention to provide an image forming apparatus comprising: a zoom lens; and an imaging element configured to receive an image formed by the zoom lens.

Compared with the prior art, the zoom lens and the imaging device provided by the invention have the following beneficial effects:

1. through the arrangement of the structure, the focal length of the telescopic end of the zoom lens is moderate, the total volume of the zoom lens is small, but the light flux of the zoom lens is large, the effect of the zoom lens in a low-light environment is improved, and the imaging quality of the zoom lens is improved.

2. Through the arrangement of the three lenses with positive focal powers, light rays are rapidly converged within a limited distance, the value of the relative aperture is increased under the condition of a certain length, the possibility of overlarge focal power of a certain lens in the third lens group is reduced, and the possibility of overlarge lens thickness is reduced.

3. The curvature radius of the two opposite side curved surfaces of the first lens and the second lens is limited, so that light rays are converged to a certain degree at the first fixed group under the condition that the integral focal power of the first fixed group is not changed, the entrance pupil is enlarged under the condition that the size of the aperture is not changed, and the brightness of the zoom lens is increased.

4. The moving distance of the fourth lens group and the second lens group is limited, so that the zooming range with small magnification of the zoom lens is realized, the possibility of changing the aperture is reduced, and the effect of keeping the aperture constant is realized.

5. The curvature radius of the curved surfaces on the two sides of the fourth lens group is limited, so that the surface of the fourth lens facing the image side has a larger curvature radius, and the fourth lens is relatively insensitive to installation errors; the curvature radius of the surface of the fourth lens facing the object side is relatively small, so that light rays can be diffused, the clear aperture at the diaphragm is large, and distortion can be controlled.

Drawings

The above features, technical features, advantages and implementation manners of a zoom lens and an imaging device will be further described in the following detailed description of preferred embodiments in a clearly understandable manner with reference to the accompanying drawings.

FIG. 1 is a schematic structural diagram of a zoom lens according to the present invention in a telephoto state;

FIG. 2 is a schematic structural diagram of a wide-angle state of a zoom lens according to the present invention;

FIG. 3 is an aberration diagram of a zoom lens in a telephoto state according to the present invention;

FIG. 4 is an aberration diagram of a wide angle state of a zoom lens according to the present invention;

FIG. 5 is a coma diagram illustrating a telephoto state of the zoom lens according to the present invention;

FIG. 6 is a coma diagram illustrating a wide angle state of a zoom lens according to the present invention;

FIG. 7 is a schematic structural diagram of a zoom lens according to the present invention in a telephoto state;

FIG. 8 is a schematic structural diagram of a wide-angle state of a zoom lens according to the present invention;

FIG. 9 is an aberration diagram of a telephoto state of the zoom lens according to the present invention;

FIG. 10 is an aberration diagram of a wide angle state of a zoom lens according to the present invention;

FIG. 11 is a coma diagram illustrating a telephoto state of the zoom lens according to the present invention;

fig. 12 is a coma aberration diagram of a wide angle state of a zoom lens according to the present invention.

The reference numbers illustrate: g1, a first lens group; g2, a second lens group; g3, a third lens group; g4, a fourth lens group; g5, a fifth lens group; g6, auxiliary components; l1, first lens; l2, second lens; l3, third lens; l4, fourth lens; l5, fifth lens; l6, sixth lens; l7, seventh lens; l8, eighth lens; l9, ninth lens; l10, tenth lens; l11, eleventh lens; l12, twelfth lens; l13, thirteenth lens; STO, stop; CG. And (4) protecting the glass.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

For the sake of simplicity, only the parts relevant to the invention are schematically shown in the drawings, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".

Example 1

As shown in fig. 1, a zoom lens, comprising, in order from an object plane side to an image plane side:

a first lens group G1 of positive power, a second lens group G2 of negative power, a third lens group G3 of positive power, a fourth lens group G4 of negative power, and a fifth lens group G5 of positive power.

The second lens group G2 and the fourth lens group G4 move in the main optical axis direction of the zoom lens;

TTL＜100mm；

2＜ft/fw＜3；

1.2＜fno＜1.3；

wherein, TTL is the total optical length of the zoom lens, ft is the focal length of the zoom lens in the telephoto state, fw is the focal length of the zoom lens in the wide angle state, and fno is the f-number of the zoom lens.

In the embodiment, through the arrangement of the structure, the focal length of the far-end of the zoom lens is moderate, the total volume of the zoom lens is small, but the light flux of the zoom lens is large, the effect of the zoom lens in a low-light environment is improved, and the imaging quality of the zoom lens is improved.

The first lens group G1 includes, in order from the object plane side to the image plane side:

a first lens L1 of positive power, a second lens L2 of positive power, and a third lens L3 of negative power.

The second lens group G2 includes, in order from the object plane side to the image plane side:

a fourth lens L4 of negative power, a fifth lens L5 of negative power, and a sixth lens L6 of positive power.

The third lens group G3 includes at least three lenses with positive refractive power.

Through the arrangement of the three lenses with positive focal powers, light rays are rapidly converged within a limited distance, the value of the relative aperture is increased under the condition of a certain length, the possibility that the focal power of one lens in the third lens group G3 is too large is also reduced, and the possibility that the thickness of the lens is too large is reduced.

The third lens group G3 includes, in order from the object plane side to the image plane side:

a seventh lens L7 of positive power, an eighth lens L8 of positive power, a ninth lens L9 of negative power, and a tenth lens L10 of positive power, wherein the ninth lens L9 and the tenth lens L10 are cemented.

The fifth lens group G5 includes, in order from the object plane side to the image plane side:

a twelfth lens L12 of positive power and a thirteenth lens L13 of negative power.

The first lens group G1 satisfies the following conditional expression:

0.55＜|(R21+R12)/(R21-R12)|＜0.7；

wherein R12 is a radius of curvature of the first lens L1 curved surface on the image plane side, and R21 is a radius of curvature of the second lens L2 curved surface on the object plane side.

In this embodiment, the curvature radius of the two opposite curved surfaces of the first lens L1 and the second lens L2 is limited, so that the light rays are converged to a certain extent at the first fixed group under the condition that the overall optical power of the first fixed group is not changed, the entrance pupil is enlarged under the condition that the aperture size is not changed, and the brightness of the zoom lens is increased.

The zoom lens satisfies the following conditional expression:

IH/fw＞0.8；

wherein IH is the image height of the zoom lens.

By defining the zoom lens image height, the size of a sensor suitable for the zoom lens is increased, and then the imaging quality of the zoom lens is increased.

The zoom lens satisfies the following conditional expression:

0.05＜S4/S2＜0.2；

wherein S4 is a moving distance of the fourth lens group G4, and S2 is a moving distance of the second lens group G2.

In the embodiment, the moving distance between the fourth lens group G4 and the second lens group G2 is limited, so that the zoom range with small magnification of the zoom lens is realized, the possibility of changing the aperture is reduced, and the effect of constant aperture is realized.

The zoom lens satisfies the following conditional expression:

1.15；＜fg3/fw＜1.25；

wherein fg3 is the focal length of the third lens group G3.

Through the limitation of the focal length of the third lens group G3, the reasonable distribution of the focal lengths of the lenses in the zoom lens is effectively realized, the possibility that the focal lengths of the rest lens groups are too large or too small is reduced, and the miniaturization of the zoom lens is further realized.

The second lens group G2 satisfies the following conditional expression:

25＜|R41/R42|＜35；

wherein R41 is a radius of curvature of the object-side curved surface of the fourth lens L4, and R42 is a radius of curvature of the image-side curved surface of the fourth lens L4.

In this embodiment, the curvature radius of the curved surfaces on both sides of the fourth lens group G4 is defined such that the fourth lens L4 has a larger curvature radius toward the image side surface, so that the fourth lens L4 is relatively insensitive to mounting errors; the fourth lens L4 has a relatively small radius of curvature toward the object side surface, and can diverge light rays, so that the clear aperture at the stop STO is relatively large, and distortion can be controlled.

The second lens group G2 satisfies the following conditional expression:

1≤R52/R61＜1.2；

wherein R52 is a radius of curvature of the fifth lens L5 on the image plane side, and R61 is a radius of curvature of the sixth lens L6 on the object plane side.

Through the limitation of the curvature radius of the fifth lens L5 and the curvature radius of the sixth lens L6, the chromatic aberration and distortion of light are improved, and the imaging quality of the zoom lens is improved.

The fourth lens group G4 is an eleventh lens L11 with negative power.

A curved surface of the thirteenth lens L13 on the object plane side and a curved surface of the twelfth lens L12 on the image plane side are both curved toward the image plane side;

and/or;

the curved surface of the eleventh lens L11 on the image plane side and the curved surface of the twelfth lens L12 on the object plane side are both curved toward the object plane side.

In the embodiment, the directions of the curved surfaces of the eleventh lens L11 to the thirteenth lens L13 are limited, so that the directions of light rays are effectively controlled, a large target surface is realized, chromatic aberration and aberration of the zoom lens are reduced, and the imaging quality of the zoom lens is improved.

Example 2

As shown in fig. 1 to 6, a zoom lens includes, in order from an object plane side to an image plane side:

a first lens group G1 of positive power, a second lens group G2 of negative power, a third lens group G3 of positive power, a fourth lens group G4 of negative power, a fifth lens group G5 of positive power, and an auxiliary member G6.

The first lens group G1 includes, in order from the object plane side to the image plane side:

a first lens L1 of positive power, a second lens L2 of positive power, and a third lens L3 of negative power, wherein the second lens L2 and the third lens L3 are cemented.

The second lens group G2 includes, in order from the object plane side to the image plane side:

a fourth lens L4 of negative power, a fifth lens L5 of negative power, and a sixth lens L6 of positive power.

The third lens group G3 includes, in order from the object plane side to the image plane side:

a seventh lens L7 of positive power, an eighth lens L8 of positive power, a ninth lens L9 of negative power, and a tenth lens L10 of positive power, wherein the ninth lens L9 and the tenth lens L10 are cemented.

The fourth lens group G4 is an eleventh lens L11 with negative power.

The fifth lens group G5 includes, in order from the object plane side to the image plane side:

a twelfth lens L12 of positive power and a thirteenth lens L13 of negative power.

The auxiliary component G6 is a piece of protective glass CG.

Table 1 shows basic lens data of the zoom lens of the present embodiment, table 2 shows variable parameters in table 1, and table 3 shows aspherical surface coefficients.

The plane number column indicates the plane number when the number is increased one by one toward the image side with the plane on the object side being the 1 st plane; the surface type column shows the surface type of a certain lens; the radius of curvature of a lens is shown in the column of radius of curvature, positive radius of curvature indicates that the surface is curved in the object side direction, and negative radius of curvature indicates that the surface is curved in the image side direction; the surface spacing on the optical axis of each surface from the surface adjacent to its image side is shown in the center thickness column; the refractive index of a certain lens is shown in the refractive index column; the abbe number of a certain lens is shown in the abbe number column.

In table 2, the WIDE column indicates specific numerical values of the respective variable parameters when the zoom lens is in the WIDE-angle end state, and the TELE column indicates specific numerical values of the respective variable parameters when the zoom lens is in the telephoto end state.

In Table 3, K is the conic coefficient and e is the scientific count number, e.g., e-005 means 10-5.

[ TABLE 1 ]

Noodle numbering	Surface type	Radius of curvature/mm	Center thickness/mm	Refractive index	Abbe number
						OBJ
S1	Spherical surface	614.40	2.84	1.71	53.94
						S2	Spherical surface	-141.44	0.10
S3	Spherical surface	35.30	6.25	1.5	81.61
						S4	Spherical surface	1066.94	0.70	1.95	17.98
S5	Spherical surface	156.87	D1
						S6	Aspherical surface	605.31	0.70	1.58	59.46
S7	Aspherical surface	19.19	6.74
						S8	Spherical surface	-21.67	0.70	1.49	70.44
S9	Spherical surface	44.01	1.45
						S10	Spherical surface	40.75	1.85	1.95	17.98
S11	Spherical surface	87.21	D2
						STO	Spherical surface	INF	0.10
S13	Aspherical surface	29.13	4.12	1.62	63.86
						S14	Aspherical surface	-49.55	2.39
S15	Spherical surface	26.71	5.59	1.44	95.1
						S16	Spherical surface	-31.35	0.10
S17	Spherical surface	-208.35	0.70	1.58	40.89
						S18	Spherical surface	12.96	5.49	1.44	95.1
S19	Spherical surface	-44.50	D3
						S20	Spherical surface	-4630.14	2.30	1.65	33.84
S21	Spherical surface	17.51	D4
						S22	Spherical surface	19.91	4.18	1.8	46.5
S23	Spherical surface	-56.83	6.47
						S24	Spherical surface	-19.61	0.70	1.73	28.32
S25	Spherical surface	8617.49	2.40
						S26	Spherical surface	INF	0.50	1.52	64.2
S27	Spherical surface	INF	0.10
						IMG

[ TABLE 2 ]

	WIDE	TELE
			D1	3.04	23.91
D2	22.93	2.06
			D3	1.00	2.95
D4	6.56	4.61

[ TABLE 3 ]

In this embodiment, TTL is 90mm, fw is 16mm, ft is 45mm, ft/fw is 2.81, fno is 1.21-1.23, IH is 13.2mm, and IH/fw is 0.825;

wherein, TTL is the total optical length of the zoom lens, ft is the focal length of the zoom lens in the telephoto state, fw is the focal length of the zoom lens in the wide angle state, fno is the f-number of the zoom lens, and IH is the image height of the zoom lens.

S4＝1.95mm，S2＝20.87mm，S4/S2＝0.093；

Wherein S4 is a moving distance of the fourth lens group G4, and S2 is a moving distance of the second lens group G2.

fg3＝19.13mm；fg3/fw＝1.2；

Wherein fg3 is the focal length of the third lens group G3.

R12＝-141.44mm，R21＝35.30mm；

|(R21+R12)/(R21-R12)|＝0.6；

Wherein R12 is a radius of curvature of the first lens L1 curved surface on the image plane side, and R21 is a radius of curvature of the second lens L2 curved surface on the object plane side.

R41＝605.31mm，R42＝19.19mm；

|R41/R42|＝31.54；

Wherein R41 is a radius of curvature of the object-side curved surface of the fourth lens L4, and R42 is a radius of curvature of the image-side curved surface of the fourth lens L4.

R52＝44.01mm，R61＝40.75mm；

R52/R61＝1.08；

Wherein R52 is a radius of curvature of the fifth lens L5 on the image plane side, and R61 is a radius of curvature of the sixth lens L6 on the object plane side.

Example 2

A zoom lens comprising, in order from an object plane side to an image plane side:

a first lens group G1 of positive power, a second lens group G2 of negative power, a third lens group G3 of positive power, a fourth lens group G4 of negative power, a fifth lens group G5 of positive power, and an auxiliary member G6.

The first lens group G1 includes, in order from the object plane side to the image plane side:

a first lens L1 of positive power, a second lens L2 of positive power, and a third lens L3 of negative power.

The second lens group G2 includes, in order from the object plane side to the image plane side:

a fourth lens L4 of negative power, a fifth lens L5 of negative power, a sixth lens L6 of positive power, wherein the fifth lens L5 and the sixth lens L6 are cemented.

The third lens group G3 includes, in order from the object plane side to the image plane side:

a seventh lens L7 of positive power, an eighth lens L8 of positive power, a ninth lens L9 of negative power, and a tenth lens L10 of positive power, wherein the ninth lens L9 and the tenth lens L10 are cemented.

The fourth lens group G4 is an eleventh lens L11 with negative power.

The fifth lens group G5 includes, in order from the object plane side to the image plane side:

a twelfth lens L12 of positive power and a thirteenth lens L13 of negative power.

The auxiliary component G6 is a piece of protective glass CG.

Table 4 shows basic lens data of the zoom lens of the present embodiment, table 5 shows variable parameters in table 4, and table 6 shows aspherical surface coefficients.

The plane number column indicates the plane number when the number is increased one by one toward the image side with the plane on the object side being the 1 st plane; the surface type column shows the surface type of a certain lens; the radius of curvature of a lens is shown in the column of radius of curvature, positive radius of curvature indicates that the surface is curved in the object side direction, and negative radius of curvature indicates that the surface is curved in the image side direction; the surface spacing on the optical axis of each surface from the surface adjacent to its image side is shown in the center thickness column; the refractive index of a certain lens is shown in the refractive index column; the abbe number of a certain lens is shown in the abbe number column.

In table 5, the WIDE column indicates specific numerical values of the respective variable parameters when the zoom lens is in the WIDE-angle end state, and the TELE column indicates specific numerical values of the respective variable parameters when the zoom lens is in the telephoto end state.

In Table 6, K is the conic coefficient and e is the scientific count number, e.g., e-005 means 10-5.

[ TABLE 4 ]

[ TABLE 5 ]

	WIDE	TELE
			D1	0.91	21.81
D2	22.59	1.69
			D3	1.00	4.38
D4	7.04	3.66

[ TABLE 6 ]

In this embodiment, TTL is 90mm, fw is 16mm, ft is 45mm, ft/fw is 2.81, fno is 1.23 to 1.27, IH is 13.2mm, and IH/fw is 0.825;

wherein, TTL is the total optical length of the zoom lens, ft is the focal length of the zoom lens in the telephoto state, fw is the focal length of the zoom lens in the wide angle state, fno is the f-number of the zoom lens, and IH is the image height of the zoom lens.

S4＝3.38mm，S2＝20.9mm，S4/S2＝0.162；

Wherein S4 is a moving distance of the fourth lens group G4, and S2 is a moving distance of the second lens group G2.

fg3＝19.12；fg3/fw＝1.2；

Wherein fg3 is the focal length of the third lens group G3.

R12＝-174.67mm，R21＝36.06mm；

|(R21+R12)/(R21-R12)|＝0.658；

Wherein R12 is a radius of curvature of the first lens L1 curved surface on the image plane side, and R21 is a radius of curvature of the second lens L2 curved surface on the object plane side.

R41＝-563.34mm，R42＝21.39mm；

|R41/R42|＝26.33；

Wherein R41 is a radius of curvature of the object-side curved surface of the fourth lens L4, and R42 is a radius of curvature of the image-side curved surface of the fourth lens L4.

R52＝R61＝49.93mm；

R52/R61＝1；

Wherein R52 is a radius of curvature of the fifth lens L5 on the image plane side, and R61 is a radius of curvature of the sixth lens L6 on the object plane side.

Example 5

An image forming apparatus, as shown in fig. 1 to 12, includes: the zoom lens described in any one of the above embodiments, and the imaging element, are configured to receive an image formed by the zoom lens.

It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.