CN116819742B - Zoom lens - Google Patents

Abstract

The invention discloses a zoom lens, which comprises a first fixed lens group, a zoom lens group, a diaphragm, a second fixed lens group, a focusing lens group and a third fixed lens group, wherein the first fixed lens group comprises a first lens, a second lens and a third lens, the zoom lens group comprises a fourth lens, a fifth lens, a sixth lens and a seventh lens, the second fixed lens group comprises an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens, the focusing lens group comprises a thirteenth lens, a fourteenth lens, a fifteenth lens and a sixteenth lens, and the third fixed lens group comprises a seventeenth lens. The zoom lens provided by the embodiment of the invention adopts a five-component structure, uses 17 lenses, realizes the 4K zoom lens with small volume, large aperture, small distortion and infrared and high-low temperature confocal by arranging the five lens groups and the focal length collocation of the 17 lenses, and meets the use requirements of small distortion, large aperture and clear imaging under a 1/1.2' target surface.

Description

Zoom lens

Technical Field

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

Background

In the security field, the zoom lens is widely applied by virtue of the advantages of long shooting distance, large shooting angle and the like, and along with the development of technology, the application of the 4K camera is gradually popularized in the security field, and the high pixel, large target surface, large aperture and small distortion become requirements on the security zoom lens of a new generation.

The target surface size of the mainstream photosensitive chip in the market is 1/1.8 ', the resolution is 8M, the market demand cannot be met more and more, the 1/1.2' target surface photosensitive chip becomes the mainstream gradually, the zoom lens capable of being matched with the photosensitive chip in the market is less in variety, and the problems of large volume, small aperture, infrared high-low temperature non-confocal, large distortion and the like exist.

Disclosure of Invention

The invention provides a zoom lens which is used for realizing a 4K zoom lens with small volume, large aperture, small distortion and infrared and high-low temperature confocal.

The invention provides a zoom lens, which comprises a first fixed lens group, a zoom lens group, a diaphragm, a second fixed lens group, a focusing lens group and a third fixed lens group which are sequentially arranged from an object plane to an image plane along an optical axis;

the first fixed lens group, the second fixed lens group and the third fixed lens group are fixedly arranged, and the zoom lens group and the focusing lens group are movably arranged along the optical axis direction;

the first fixed lens group has positive focal power, the zoom lens group has negative focal power, the second fixed lens group has positive focal power, the focusing lens group has positive focal power, and the third fixed lens group has negative focal power;

The first fixed lens group comprises a first lens, a second lens and a third lens which are sequentially arranged from an object plane to an image plane; the first lens has negative focal power, the second lens has positive focal power, and the third lens has positive focal power;

the zoom lens group comprises a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from an object plane to an image plane; the fourth lens has negative focal power, the fifth lens has negative focal power, the sixth lens has positive focal power, and the seventh lens has negative focal power;

the second fixed lens group comprises an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens which are sequentially arranged from the object plane to the image plane; the eighth lens has positive optical power, the ninth lens has negative optical power, the tenth lens has positive optical power, the eleventh lens has negative optical power, and the twelfth lens has positive or negative optical power;

the focusing lens group comprises a thirteenth lens, a fourteenth lens, a fifteenth lens and a sixteenth lens which are sequentially arranged from an object plane to an image plane; the thirteenth lens has positive or negative optical power, the fourteenth lens has positive optical power, the fifteenth lens has positive optical power, and the sixteenth lens has positive or negative optical power;

The third fixed lens group includes a seventeenth lens having negative optical power.

Optionally, at least one of the seventh lens, the twelfth lens, the thirteenth lens, the fifteenth lens, and the seventeenth lens is an aspherical lens.

Optionally, the fifth lens and the sixth lens form a double cemented lens group.

Optionally, at least two of the eighth lens, the ninth lens, the tenth lens, the eleventh lens, and the twelfth lens constitute a cemented lens group.

Optionally, at least two of the ninth lens, the tenth lens and the eleventh lens form the cemented lens group;

and the total focal length of the ninth lens, the tenth lens and the eleventh lens is F, and the focal length of the zoom lens at the long focal end is FT, wherein F/FT is more than or equal to 1.32 and less than or equal to 66.5.

Optionally, the focal length of the first fixed lens group is F1, the focal length of the zoom lens group is F2, the focal length of the second fixed lens group is F3, the focal length of the focusing lens group is F4, the focal length of the third fixed lens group is F5, and the focal length of the zoom lens at the wide-angle end is FW,

3.544≤F1/FW≤3.681；-1.155≤F2/FW≤-1.057；1.746≤F3/FW≤1.778；

1.537≤F4/FW≤2.179；-42.359≤F5/FW≤-1.798。

Optionally, the maximum movable distance of the zoom lens group is S2, and the maximum movable distance of the focusing lens group is S4, wherein S2/S4 is more than or equal to 4.044 and less than or equal to 4.680.

Optionally, the refractive index of the sixth lens is nd6, and the abbe number is vd6; the refractive index of the seventh lens is nd7, and the Abbe number is vd7; the refractive index of the ninth lens is nd9, and the Abbe number is vd9; the refractive index of the tenth lens is nd10, and the Abbe number is vd10; the refractive index of the eleventh lens is nd11, and the Abbe number is vd11; the refractive index of the sixteenth lens is nd16, and the Abbe number is vd16; the refractive index of the seventeenth lens is nd17, and the Abbe number is vd17; wherein,

2.00≤nd6≤2.05；25.47≤vd6≤28.47；

1.54≤nd7≤1.57；59.80≤vd7≤83.35；

1.64≤nd9≤1.70；47.55≤vd9≤58.73；

1.44≤nd10≤1.59；69.20≤vd10≤95.12；

1.80≤nd11≤1.85；30.39≤vd11≤36.00；

1.53≤nd16≤1.54；57.83≤vd16≤70.70；

1.54≤nd17≤1.57；47.20≤vd17≤70.00。

optionally, the focal length of the zoom lens at the wide angle end is FW, and the focal length of the zoom lens at the telephoto end is FT, wherein FT/FW is more than or equal to 3.3 and less than or equal to 3.4.

Optionally, the total optical length of the zoom lens is TTL, the maximum movable distance of the zoom lens group is S2, the maximum movable distance of the focus lens group is S4, wherein,

3.800≤TTL/S2≤4.32；16.5≤TTL/S4≤18.05。

according to the zoom lens provided by the embodiment of the invention, a five-component structure is adopted, 17 lenses are adopted, the focal length of the five lens groups is matched in a positive-negative-positive-negative matching mode, and the focal length matching of the 17 lenses is further limited, so that the total optical length of the zoom lens is smaller than 91mm, the F-number FNO satisfies 1.35< FNO <1.51 under a 1/1.2 'target surface, and the distortion in a 405 nm-870nm wave band is smaller than 10%, thereby realizing a 4K zoom lens with small volume, large aperture, small distortion and infrared and high-low temperature confocal, and meeting the use requirements of small distortion, large aperture and clear imaging under a 1/1.2' target surface.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a zoom lens at a wide-angle end according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a zoom lens at a telephoto end according to an embodiment of the present invention;

FIG. 3 is a graph showing a chromatic aberration of a zoom lens at a wide-angle end according to an embodiment of the present invention;

FIG. 4 is a graph showing a vertical axis chromatic aberration curve of a zoom lens at a telephoto end according to an embodiment of the present invention;

fig. 5 to 11 are light ray fan diagrams of the zoom lens according to the first embodiment of the present invention at different angles of view at the wide angle end;

Fig. 12 to 18 are light ray fan diagrams of the zoom lens according to the first embodiment of the present invention under different angles of view at the telephoto end;

fig. 19 is a field curvature distortion diagram of a zoom lens at a wide-angle end according to an embodiment of the present invention;

FIG. 20 is a graph showing distortion of a field curvature of a zoom lens at a telephoto end according to an embodiment of the present invention;

fig. 21 is a schematic structural diagram of a zoom lens at a wide-angle end according to a second embodiment of the present invention;

fig. 22 is a schematic structural diagram of a zoom lens at a telephoto end according to a second embodiment of the present invention;

FIG. 23 is a graph showing a chromatic aberration of a zoom lens at a wide-angle end according to a second embodiment of the present invention;

FIG. 24 is a graph showing a vertical axis chromatic aberration curve of a zoom lens at a telephoto end according to a second embodiment of the present invention;

fig. 25 to 31 are light ray fan diagrams of the zoom lens according to the second embodiment of the present invention at different angles of view at the wide angle end;

fig. 32-38 are light ray fan diagrams of the zoom lens provided in the second embodiment of the present invention under different angles of view at the telephoto end;

fig. 39 is a field curvature distortion diagram of a zoom lens at a wide-angle end according to a second embodiment of the present invention;

FIG. 40 is a graph of distortion of field curvature of a zoom lens at a telephoto end according to a second embodiment of the present invention;

fig. 41 is a schematic view of a zoom lens according to a third embodiment of the present invention at a wide-angle end;

Fig. 42 is a schematic structural diagram of a zoom lens at a telephoto end according to a third embodiment of the present invention;

FIG. 43 is a graph showing a chromatic aberration in the vertical axis of a zoom lens at the wide-angle end according to the third embodiment of the present invention;

FIG. 44 is a graph of chromatic aberration of a zoom lens at a telephoto end according to a third embodiment of the present invention;

fig. 45-52 are light ray fan diagrams of a zoom lens according to a third embodiment of the present invention at different angles of view at the wide-angle end;

fig. 53-60 are light ray fan diagrams of a zoom lens according to a third embodiment of the present invention under different angles of view at a telephoto end;

fig. 61 is a field curvature distortion diagram of a zoom lens at a wide-angle end according to a third embodiment of the present invention;

fig. 62 is a field curvature distortion diagram of a zoom lens at a telephoto end according to a third embodiment of the present invention.

Detailed Description

In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 1 is a schematic view of a zoom lens at a wide angle end according to an embodiment of the present invention, and fig. 2 is a schematic view of a zoom lens at a telephoto end according to an embodiment of the present invention, where, as shown in fig. 1 and fig. 2, the zoom lens according to an embodiment of the present invention includes a first fixed lens group G1, a zoom lens group G2, a stop STO, a second fixed lens group G3, a focusing lens group G4, and a third fixed lens group G5 sequentially arranged from an object plane to an image plane along an optical axis.

The first fixed lens group G1, the second fixed lens group G3, and the third fixed lens group G5 are fixedly disposed, and the zoom lens group G2 and the focus lens group G4 are movably disposed in the optical axis direction.

The first fixed lens group G1 has positive power, the zoom lens group G2 has negative power, the second fixed lens group G3 has positive power, the focus lens group G4 has positive power, and the third fixed lens group G5 has negative power.

The first fixed lens group G1 includes a first lens L1, a second lens L2, and a third lens L3, which are sequentially arranged from an object plane to an image plane, the first lens L1 having negative optical power, the second lens L2 having positive optical power, and the third lens L3 having positive optical power.

The zoom lens group G2 includes a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7, which are sequentially arranged from the object plane to the image plane, the fourth lens L4 having negative power, the fifth lens L5 having negative power, the sixth lens L6 having positive power, and the seventh lens L7 having negative power.

The second fixed lens group G3 includes an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, and a twelfth lens L12, which are sequentially arranged from the object plane to the image plane, the eighth lens L8 having positive optical power, the ninth lens L9 having negative optical power, the tenth lens L10 having positive optical power, the eleventh lens L11 having negative optical power, and the twelfth lens L12 having positive optical power or negative optical power.

The focus lens group G4 includes a thirteenth lens L13, a fourteenth lens L14, a fifteenth lens L15, and a sixteenth lens L16, which are arranged in order from the object plane to the image plane, the thirteenth lens L13 having positive power or negative power, the fourteenth lens L14 having positive power, the fifteenth lens L15 having positive power, and the sixteenth lens L16 having positive power or negative power.

The third fixed lens group G5 includes a seventeenth lens L17, and the seventeenth lens L17 has negative optical power.

Specifically, as shown in fig. 1 and fig. 2, the zoom lens provided in the embodiment of the present invention is arranged in order from an object side to an image side along an optical axis: the lens system comprises a first fixed lens group G1 with positive focal power, a zoom lens group G2 with negative focal power, a diaphragm 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 negative focal power.

The first fixed lens group G1 is composed of 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 zoom lens group G2 is composed of 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 second fixed lens group G3 is composed of an eighth lens L8 having positive optical power, a ninth lens L9 having negative optical power, a tenth lens L10 having positive optical power, an eleventh lens L11 having negative optical power, and a twelfth lens L12 having positive or negative optical power.

The focus lens group G4 is composed of a thirteenth lens L13 having positive or negative optical power, a fourteenth lens L14 having positive optical power, a fifteenth lens L15 having positive optical power, and a sixteenth lens L16 having positive or negative optical power.

The third fixed lens group G5 is composed of only the seventeenth lens L17 having negative optical power.

In the zoom lens provided in the embodiment of the present invention, the first fixed lens group G1, the zoom lens group G2, the second fixed lens group G3, the focus lens group G4, and the third fixed lens group G5 may be disposed in one barrel (not shown), but are not limited thereto.

Wherein, the first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in position in the lens barrel so that the first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed relative to the image plane.

The zoom lens group G2 and the focus lens group G4 can reciprocate along the optical axis in the lens barrel, the zoom lens group G2 can play a role in zooming, the focus lens group G4 can play a role in focusing, and switching of the zoom lens at the wide angle end and the telephoto end can be achieved by changing the positions of the zoom lens group G2 and the focus lens group G4 on the optical axis.

It is understood that in the zoom lens in which zooming is achieved by changing the positions of the zoom lens group G2 and the focus lens group G4 on the optical axis, the zoom lens is at the wide-angle end when the focal length is shortest, and at the telephoto end when the focal length is longest, the zoom lens is at the telephoto end, and the zoom lenses have different focal lengths and powers at the wide-angle end and the telephoto end.

Further, the focal length is a measure of the concentration or divergence of light in an optical system, and refers to the distance from the optical center of a lens to the focal point of light concentration when parallel light is incident. Simply stated, the focal length is the distance between the focal point and the center point of the mirror. The smaller the absolute value of the focal length, the stronger the ability to bend the light, the larger the absolute value of the optical power, and the weaker the ability to bend the light. When the focal length is positive, the refraction of the light rays is convergent; when the focal length is negative, the refraction of the light is divergent. The focal length may be adapted to characterize a refractive surface of a lens (i.e. a surface of a lens), may be adapted to characterize a lens, or may be adapted to characterize a system of lenses together (i.e. a lens group).

In the embodiment of the present invention, 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 can enter the subsequent structure through the first fixed lens group G1.

The diaphragm STO is arranged between the seventh lens L7 and the eighth lens L8, so that the advanced aberration of the zoom lens can be well controlled at the front end of the zoom lens, and the functions of enlarging the target surface and improving the image quality are achieved.

Optionally, with continued reference to fig. 1 and 2, the zoom lens may further include a plate glass CG located on the image side surface side of the seventeenth lens L17 to protect the photosensitive chip in the imaging sensor. The photosensitive chip is used for converting optical signals collected by the zoom lens into electric signals, so that the imaging effect of the zoom lens is guaranteed.

According to the zoom lens provided by the embodiment of the invention, a five-component structure is adopted, 17 lenses are adopted, the focal length of the five lens groups is matched in a positive-negative-positive-negative matching mode, and the focal length matching of the 17 lenses is further limited, so that the total optical length of the zoom lens is smaller than 91mm, the F-number FNO satisfies 1.35< FNO <1.51 under a 1/1.2 'target surface, and the distortion in a 405 nm-870nm wave band is smaller than 10%, thereby realizing a 4K zoom lens with small volume, large aperture, small distortion and infrared and high-low temperature confocal, and meeting the use requirements of small distortion, large aperture and clear imaging under a 1/1.2' target surface.

As one possible embodiment, at least one of the seventh lens L7, the twelfth lens L12, the thirteenth lens L13, the fifteenth lens L15, and the seventeenth lens L17 is an aspherical lens.

The seventh lens L7 is an aspheric lens, that is, the lens closest to the image plane in the zoom lens group G2 is an aspheric lens, which can play a role in controlling chromatic aberration before the stop STO, and meanwhile, the zoom lens group G2 is matched with the aspheric lens to ensure smooth light passing through the zoom lens and realize a longer focal length.

At least one of the twelfth lens L12, the thirteenth lens L13, and the fifteenth lens L15 employs an aspherical lens, and can correct chromatic aberration and the like advanced aberration after passing through the stop STO, and distortion.

The seventeenth lens L17 is an aspherical lens, that is, the third fixed lens group G5 is composed of an aspherical lens, and can correct the advanced aberration after the stop, so as to help reduce the distortion of the lens, and also has a certain control effect on other parameters of the lens, such as CRA.

Further, at least one plastic aspherical lens exists in each of the zoom lens group G2, the second fixed lens group G3 and the focusing lens group G4, so that chromatic aberration and other advanced aberrations of the lens can be further reduced, and distortion of the lens can be reduced. Meanwhile, the aspheric lens is arranged in front of the diaphragm STO and matched with the aspheric lens behind the diaphragm STO, so that full-band confocal of the lens at 436 nm-870nm is facilitated, the image quality is high, and the use requirements under more conditions can be met.

Further, the zoom lens includes at least five plastic aspheric lenses, for example, the seventh lens L7, the twelfth lens L12, the thirteenth lens L13, the fifteenth lens L15 and the seventeenth lens L17 are all plastic aspheric lenses, which can correct the advanced aberration to a greater extent, reduce the distortion of the lens, realize the confocal of the lens in the full wave band of 436 nm-870 nm, improve the image quality, and meet the use requirements in more situations.

It should be noted that, in the zoom lens provided by the embodiment of the present invention, all the aspherical lenses may be plastic aspherical lenses, and the lenses other than the aspherical lenses may be spherical glass lenses. The glass and the plastic can play a role in mutual compensation, so that the high temperature and the low temperature can be balanced, the optical total length of the lens can be reduced, the zoom lens has the characteristic of stable high temperature and low temperature performance, the environmental adaptability of the zoom lens is improved, and meanwhile, the aberration can be well corrected. The temperature coefficient of the glass-plastic mixed material is reasonably matched, so that the lens can be well resolved in a high-low temperature environment of-20 ℃ to 70 ℃, the weight of the lens can be obviously reduced, and in addition, compared with a glass lens, the cost of the plastic lens has obvious advantages, and the cost of the zoom lens can be reduced.

The material of the plastic aspheric lens can be various plastics known to those skilled in the art, and the material of the glass spherical lens can be various types of glass known to those skilled in the art.

As one possible embodiment, as shown in fig. 1 and 2, the first lens L1 and the second lens L2 constitute a cemented lens group, and/or the fifth lens L5 and the sixth lens L6 constitute a cemented lens group.

The first lens L1 and the second lens L2 form a double-cemented lens group, which can control chromatic aberration and distortion of the lens before the stop STO, and simultaneously, can effectively reduce the air space between the first lens L1 and the second lens L2, thereby being beneficial to reducing the total optical length of the lens, reducing the light quantity loss caused by reflection between lenses, improving the illuminance, improving the image quality and improving the imaging definition of the lens.

Similarly, the fifth lens L5 and the sixth lens L6 form a double-cemented lens group, which can correct chromatic aberration and distortion of the lens after the stop STO, and simultaneously effectively reduce the air space between the fifth lens L5 and the sixth lens L6, thereby being beneficial to reducing the total optical length of the lens, reducing the light quantity loss caused by reflection between lenses, improving the illuminance, improving the image quality and improving the imaging definition of the lens.

It should be noted that, the first lens L1 and the second lens L2, and the fifth lens L5 and the sixth lens L6 may be detachable for use, and may be configured according to practical requirements.

As a possible embodiment, as shown in fig. 1 and 2, at least two of the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, and the twelfth lens L12 constitute a cemented lens group.

The second fixed lens group G3 at least includes a cemented lens group formed by cementing 2 or 3 adjacent lenses, and when light rays just pass through the stop STO, the cemented lens group can well correct chromatic aberration, so that the situation that chromatic aberration is superimposed at the rear end of the lens to cause that a large amount of lenses with high abbe number materials are required to be pulled back at the rear end of the lens is avoided, and the cost is saved and the image quality is improved.

As a possible embodiment, with continued reference to fig. 1 and 2, at least two of the ninth lens L9, tenth lens L10, and eleventh lens L11 constitute a cemented lens group. The total focal length of the ninth lens L9, the tenth lens L10 and the eleventh lens L11 is F, and the focal length of the zoom lens at the long focal end is FT, wherein F/FT is more than or equal to 1.32 and less than or equal to 66.5.

Among them, the ninth lens L9, the tenth lens L10, and the eleventh lens L11 may constitute a triple cemented lens group, or the ninth lens L9, the tenth lens L10, and the eleventh lens L11 are split into a double cemented lens group and a single lens for use, that is, the ninth lens L9 and the tenth lens L10 constitute a double cemented lens group, or the tenth lens L10 and the eleventh lens L11 constitute a double cemented lens group. By the arrangement, chromatic aberration can be better corrected under the condition that light just passes through the diaphragm STO, the situation that chromatic aberration is corrected by a large amount of lenses with high Abbe number materials at the rear end of the lens due to the superposition of chromatic aberration at the rear end of the lens is avoided, and the cost is saved while the image quality can be further improved.

Further, the total focal length F of the ninth lens L9, the tenth lens L10 and the eleventh lens L11 and the focal length FT of the zoom lens at the telephoto end satisfy 1.32F/FT being less than or equal to 66.5, so that the focal powers in the lens group unit formed by the ninth lens L9, the tenth lens L10 and the eleventh lens L11 in the second fixed lens group G3 are respectively represented as a negative-positive-negative collocation, so that the focal powers of the lens group unit formed by the ninth lens L9, the tenth lens L10 and the eleventh lens L11 are smaller, the light is ensured to be substantially free from deflection when passing through the lens group unit, and severe advanced aberration generated in the lens group unit can be avoided.

The total focal length F of the ninth lens L9, the tenth lens L10, and the eleventh lens L11 refers to the focal length of the lens group unit composed of the ninth lens L9, the tenth lens L10, and the eleventh lens L11.

As a possible embodiment, with continued reference to fig. 1 and 2, in the first fixed lens group G1, the object-side surface of the first lens element L1 is convex, and the image-side surface of the first lens element L1 is concave. The object side surface and the image side surface of the second lens L2 are both convex. The object side surface of the third lens element L3 is convex, and the image side surface of the third lens element L3 is concave.

In the zoom lens group G2, the object-side surface of the fourth lens element L4 is convex, and the image-side surface of the fourth lens element L4 is concave. The object side surface and the image side surface of the fifth lens element L5 are concave. The object side surface of the sixth lens element L6 is convex. The object side surface and the image side surface of the seventh lens L7 are both concave surfaces.

In the second fixed lens group G3, both the object-side surface and the image-side surface of the eighth lens element L8 are convex. The object side surface of the ninth lens element L9 is convex, and the image side surface of the ninth lens element L9 is concave. The object side surface and the image side surface of the tenth lens L10 are both convex. The object side surface of the eleventh lens L11 is a concave surface. The object side surface of the twelfth lens element L12 is concave, and the image side surface of the twelfth lens element L12 is convex; alternatively, the object side surface of the twelfth lens element L12 is convex, and the image side surface of the twelfth lens element L12 is concave.

In the focusing lens group G4, the object-side surface of the thirteenth lens element L13 is convex, and the image-side surface of the thirteenth lens element L13 is concave; alternatively, the object side surface of the thirteenth lens element L13 is concave, and the image side surface of the thirteenth lens element L13 is convex. The object side surface and the image side surface of the fourteenth lens L14 are both convex. The object side surface of the fifteenth lens element L15 is concave, and the image side surface of the fifteenth lens element L15 is convex; alternatively, the object side surface and the image side surface of the fifteenth lens L15 are concave surfaces. The sixteenth lens element L16 has a convex object-side surface, and the sixteenth lens element L16 has a concave image-side surface; alternatively, both the object side surface and the image side surface of the sixteenth lens L16 are convex.

In the third fixed lens group G5, an object-side surface of the seventeenth lens L17 is a concave surface, and an image-side surface of the seventeenth lens L17 is a convex surface; alternatively, the object side surface of the seventeenth lens L17 is a convex surface, and the image side surface of the seventeenth lens L17 is a concave surface.

By limiting the bending direction of each lens surface, the focal length matching of each lens in the embodiment is realized, the 4K zoom lens with small volume, large aperture, small distortion and infrared and high-low temperature confocal is realized, and meanwhile, the gluing requirement among the lenses can be met, so that the chromatic aberration and distortion of the lens can be corrected, the imaging quality can be improved, and the optical total length of the lens can be shortened.

As a possible embodiment, the focal length of the first fixed lens group G1 is F1, the focal length of the zoom lens group G2 is F2, the focal length of the second fixed lens group G3 is F3, the focal length of the focusing lens group G4 is F4, the focal length of the third fixed lens group G5 is F5, and the focal length of the zoom lens at the wide-angle end is FW, wherein 3.544 +.f1/fw+. 3.681; -1.155.ltoreq.F2/FW.ltoreq.1.057; 1.746F 3/FW is less than or equal to 1.778; F4/FW is more than or equal to 1.537 and less than or equal to 2.179; 42.359 is less than or equal to F5/FW is less than or equal to-1.798.

The focal length of each lens is limited, so that the focal power of each lens can be reasonably matched, light rays smoothly pass through the zoom lens, and the influence of high-grade aberration on imaging quality is corrected to a greater extent.

As a possible embodiment, the maximum movable distance of the zoom lens group G2 is S2, and the maximum movable distance of the focus lens group G4 is S4, wherein 4.044+.s2/s4+. 4.680.

Wherein, by controlling the moving distance of the zoom lens group G2 and the focus lens group G4, the volume of the focus lens group G4 can be reduced to a large extent, thereby reducing the volume of the zoom lens to a large extent.

As a possible embodiment, the refractive index of the sixth lens L6 is nd6, and the abbe number is vd6; the refractive index of the seventh lens L7 is nd7, and the abbe number is vd7; the refractive index of the ninth lens L9 is nd9, and the abbe number is vd9; the tenth lens L10 has a refractive index nd10 and an abbe number vd10; the refractive index of the eleventh lens L11 is nd11, and the abbe number is vd11; the sixteenth lens L16 has a refractive index nd16 and an abbe number vd16; the seventeenth lens L17 has a refractive index nd17 and an abbe number vd17; wherein nd6 is more than or equal to 2.00 and less than or equal to 2.05; vd6 is more than or equal to 25.47 and less than or equal to 28.47; nd7 is more than or equal to 1.54 and less than or equal to 1.57;59.80 vd7 is less than or equal to 83.35; nd9 is more than or equal to 1.64 and less than or equal to 1.70; vd9 is more than or equal to 47.55 and less than or equal to 58.73; nd10 is more than or equal to 1.44 and less than or equal to 1.59; vd10 is more than or equal to 69.20 and less than or equal to 95.12; nd11 is more than or equal to 1.80 and less than or equal to 1.85; vd11 is less than or equal to 30.39 and less than or equal to 36.00; nd16 is more than or equal to 1.53 and less than or equal to 1.54;57.83 is less than or equal to vd16 is less than or equal to 70.70; nd17 is more than or equal to 1.54 and less than or equal to 1.57; 47.20.ltoreq.vd 17.ltoreq.70.00.

The refractive index is the ratio of the propagation speed of light in vacuum to the propagation speed of light in the medium, and is mainly used for describing the refractive power of materials to light, the refractive indexes of different materials are different, and the higher the refractive index of the material is, the stronger the refractive power of incident light is.

The abbe number is an index for indicating the dispersion ability of the transparent medium, and the more serious the medium dispersion, the smaller the abbe number; conversely, the more slightly the dispersion of the medium, the greater the Abbe number.

In the embodiment of the invention, the sixth lens L6 is a lens with a large refractive index, so that the light has a larger incident caliber in front of the stop STO, and thus has a larger advantage in the directions of correcting the advanced aberration, increasing the image height, and the like. Meanwhile, when the sixth lens L6 and the seventh lens L7 are used in combination, the refractive index and abbe number of the sixth lens L6 and the seventh lens L7 can be matched to better correct the influence of chromatic aberration on subsequent imaging.

In addition, by controlling the refractive index and abbe number of the ninth lens L9, the tenth lens L10 and the eleventh lens L11 to cooperate, the maximum light caliber passing through the stop STO can be controlled, the influence caused by advanced aberration is avoided, and meanwhile, under the condition of collocation of the refractive index and the abbe number of the lenses, a certain chromatic aberration control effect can be achieved, and a wider imaging wave band range is obtained.

In addition, the refractive index and abbe number of the sixteenth lens L16 and the seventeenth lens L17 are controlled, so that on one hand, smooth emergent light of the front end of the lens can be ensured, better resolution and image height are ensured, and on the other hand, chromatic aberration can be corrected at the tail end of the lens by high abbe number, so that clear imaging of the lens in all wave bands is further ensured.

As a possible embodiment, the focal length of the zoom lens at the wide-angle end is FW, and the focal length of the zoom lens at the telephoto end is FT, wherein 3.3+.ft/fw+.3.4.

The zoom lens can control distortion in a reasonable small range by controlling the focal length ratio of the zoom lens at the wide angle end and the long focal end under the condition of guaranteeing a zoom range and a large target surface, so that the requirement of small distortion of the lens is met.

As a possible implementation manner, the optical total length of the zoom lens is TTL, the maximum movable distance of the zoom lens group G2 is S2, and the maximum movable distance of the focusing lens group G4 is S4, wherein 3.800 is equal to or less than TTL/S2 is equal to or less than 4.32; TTL/S4 is 16.5-18.05.

The total optical length TTL of the zoom lens refers to a distance from an optical axis center of an object side surface of the first lens L1 to an image plane.

In the present embodiment, by defining the relationship between the moving distances of the zoom lens group G2 and the focus lens group G4 and the total optical length TTL of the zoom lens, the lens space can be compressed, ensuring that the volume of the zoom lens is small, and satisfying the requirements of the imaging quality and the magnification degree.

Specific examples of the zoom lens applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

Example 1

With continued reference to fig. 1 and 2, a zoom lens according to a first embodiment of the present invention includes a first fixed lens group G1, a zoom lens group G2, a stop STO, a second fixed lens group G3, a focusing lens group G4, and a third fixed lens group G5 sequentially arranged along an optical axis from an object plane to an image plane, where the first fixed lens group G1, the second fixed lens group G3, and the third fixed lens group G5 are fixedly disposed, and the zoom lens group G2 and the focusing lens group G4 are movably disposed along the optical axis direction. The first fixed lens group G1 includes a first lens L1, a second lens L2, and a third lens L3, which are sequentially arranged from an object plane to an image plane. The zoom lens group G2 includes a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7, which are arranged in order from the object plane to the image plane. The second fixed lens group G3 includes an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, and a twelfth lens L12, which are arranged in order from the object plane to the image plane. The focus lens group G4 includes a thirteenth lens L13, a fourteenth lens L14, a fifteenth lens L15, and a sixteenth lens L16, which are arranged in order from the object plane to the image plane. The third fixed lens group G5 includes a seventeenth lens L17.

And a piece of plate glass CG is further arranged from the object plane to the image plane, the plate glass CG is positioned on one side of the image side surface of the seventeenth lens L17, and the plate glass CG can protect a photosensitive chip in the imaging sensor, wherein the photosensitive chip is used for converting optical signals collected by the zoom lens into electric signals, and further, the imaging effect of the zoom lens is guaranteed.

In the zoom lens provided in the present embodiment, the first fixed lens group G1, the zoom lens group G2, the second fixed lens group G3, the focus lens group G4, and the third fixed lens group G5 may be disposed in one barrel (not shown in fig. 1 and 2). The first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in position in the lens barrel, the zoom lens group G2 and the focusing lens group G4 can reciprocate along the optical axis in the lens barrel, and the focal length of the zoom lens can be continuously changed from a wide angle to a long focus through the common movement of the zoom lens group G2 and the focusing lens group G4, so that the high image quality of the zoom lens at each focal position is ensured.

Table 1 details specific optical and physical parameters of each lens in the zoom lens according to the first embodiment of the present invention, and the zoom lens in table 1 corresponds to the zoom lens shown in fig. 1 and 2.

Table 1 design values of optical physical parameters of zoom lens

Wherein, the surface numbers in table 1 are numbered according to the surface order of the respective lenses, for example, the surface number "1" represents the object side surface of the first lens L1, the surface number "2" represents the image side surface of the first lens L1, and so on; "STO" represents a stop of the zoom lens; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents the surface curved to the image plane side, a negative value represents the surface curved to the object plane side, where "INF" represents the surface as a plane and the radius of curvature is infinity; thickness represents the center axial distance from the current surface to the next surface, and the unit of curvature radius and thickness are millimeters (mm); material (nd) represents the refractive index, i.e. the ability of the material between the current surface and the next surface to deflect light, and space represents the current position as air, with a refractive index of 1; the material (vd) represents abbe number (also called abbe number), i.e. the dispersion characteristic of the material from the current surface to the next surface for light, and the blank represents the current position as air; the half-aperture represents the corresponding half-height of the light on the surface of each lens.

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

Table 2 design values of zoom intervals of zoom lenses

The zoom interval in table 2 is an interval value of the zoom lens at the wide angle end and the telephoto end.

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

wherein Z is the axial distance from the curved surface at the position perpendicular to the optical axis and with the height r to the vertex of the curved surface along the optical axis direction; c represents the curvature at the apex of the aspherical surface;、/>、/>、/>、/>、/>、/>、/>and->High-order aspheric coefficients of fourth order, sixth order, eighth order, tenth order, fourteen order, sixteen order, eighteen order and twenty order corresponding to the aspheric surface>Combining into high order terms corresponding to the aspherical surface.

Table 3 details the aspherical coefficients of the lenses in this example one, by way of example, in one possible implementation.

Table 3 design values of aspherical coefficients of each lens in zoom lens

The zoom lens of the first embodiment achieves the following technical indexes:

table 4 technical index of zoom lens

Further, fig. 3 is a graph of chromatic aberration of a zoom lens at a wide angle end provided in the first embodiment of the present invention, and fig. 4 is a graph of chromatic aberration of a zoom lens at a telephoto end provided in the first embodiment of the present invention, wherein, as shown in fig. 3 and 4, a vertical direction indicates normalization of an aperture, 0 indicates on an optical axis, and a vertex in the vertical direction indicates a maximum pupil radius; the dominant wavelength was 546.07nm and the horizontal direction represents the offset from the dominant wavelength in micrometers (μm). The maximum field of view in fig. 3 and 4 is 6.55 millimeters. As can be seen from fig. 3 and 4, when the zoom lens is at the wide-angle end, the chromatic aberration of the vertical axis of different wavelengths is controlled within a (-3 μm, +2 μm) range; when the zoom lens is at the tele end, the vertical axis chromatic aberration of different wavelengths is controlled within (-6 mu m, +2 mu m), which indicates that the vertical axis chromatic aberration of the zoom lens at the wide angle end and the tele end is better controlled, and the wide spectrum application requirement of the whole wave band can be met.

Fig. 5 to 11 are light ray fan diagrams of the zoom lens according to the first embodiment of the present invention at different angles of view at the wide angle end, and fig. 12 to 18 are light ray fan diagrams of the zoom lens according to the first embodiment of the present invention at different angles of view at the telephoto end, wherein the light ray fan diagrams are one of the conventional evaluation methods for optical designers at present. In the figure, the abscissa represents the normalized beam aperture, and the ordinate represents the vertical aberration. Ideally, each curve is completely coincident with the abscissa axis, and all light rays in the field of view are focused on the same point on the image plane; the ordinate in the image may also be expressed as the maximum extent of dispersion of the light beam in the ideal plane. The light fan graph can reflect monochromatic aberration with different wavelengths and also can show the magnitude of vertical axis chromatic aberration. The maximum scale in FIGS. 5-18 is 50 μm. As can be seen from fig. 5 to fig. 18, the zoom lens has better wavelengths close to the abscissa under each view field, which indicates that the chromatic aberration of each wavelength is better corrected. In addition, the curves of all colors are not obviously dispersed, so that the zoom lens has better correction on chromatic aberration, and the imaging requirement of clear imaging of the full wave band of the zoom lens is ensured.

Fig. 19 is a field curvature distortion diagram of a zoom lens at a wide angle end according to an embodiment of the present invention, and fig. 20 is a field curvature distortion diagram of a zoom lens at a telephoto end according to an embodiment of the present invention, as shown in fig. 19 and 20, in a left coordinate system of the drawings, a horizontal coordinate represents a magnitude of a field curvature of the zoom lens in mm; the vertical coordinates represent the normalized image height without units; in the right coordinate system, the horizontal coordinate represents the magnitude of distortion (F-Tan (Theta)) in units of; the vertical coordinates represent the normalized image height without units; the maximum field of view in fig. 19 is 25.159 degrees and the maximum field of view in fig. 20 is 7.322 degrees. As can be seen from fig. 19 and 20, the zoom lens provided in the present embodiment is effectively controlled in field curvature from light having a wavelength of 436nm to light having a wavelength of 870nm at the wide angle end and the telephoto end, that is, the difference between the image quality at the center and the image quality at the periphery is small at the time of imaging. Meanwhile, the distortion of the zoom lens at the wide angle end is within-7% -1%, and the distortion of the zoom lens at the tele end is within-1% -3%, so that the distortion of the zoom lens at the wide angle end and the tele end provided by the embodiment is well corrected, and the imaging distortion is small.

Example two

Fig. 21 is a schematic view of a zoom lens provided in the second embodiment of the present invention at a wide angle end, and fig. 22 is a schematic view of a zoom lens provided in the second embodiment of the present invention at a telephoto end, where, as shown in fig. 21 and 22, the zoom lens provided in the second embodiment of the present invention includes a first fixed lens group G1, a zoom lens group G2, a stop STO, a second fixed lens group G3, a focusing lens group G4, and a third fixed lens group G5 sequentially arranged from an object plane to an image plane along an optical axis, where the first fixed lens group G1, the second fixed lens group G3, and the third fixed lens group G5 are fixedly arranged, and the zoom lens group G2 and the focusing lens group G4 are movably arranged along the optical axis direction. The first fixed lens group G1 includes a first lens L1, a second lens L2, and a third lens L3, which are sequentially arranged from an object plane to an image plane. The zoom lens group G2 includes a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7, which are arranged in order from the object plane to the image plane. The second fixed lens group G3 includes an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, and a twelfth lens L12, which are arranged in order from the object plane to the image plane. The focus lens group G4 includes a thirteenth lens L13, a fourteenth lens L14, a fifteenth lens L15, and a sixteenth lens L16, which are arranged in order from the object plane to the image plane. The third fixed lens group G5 includes a seventeenth lens L17. And a piece of plate glass CG is further arranged along the object plane to the image plane, the plate glass CG is positioned on one side of the image side surface of the seventeenth lens L17, and the plate glass CG can protect a photosensitive chip in the imaging sensor.

In the zoom lens provided in the present embodiment, the first fixed lens group G1, the zoom lens group G2, the second fixed lens group G3, the focus lens group G4, and the third fixed lens group G5 may be disposed in one barrel (not shown in fig. 21 and 22). The first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in position in the lens barrel, the zoom lens group G2 and the focusing lens group G4 can reciprocate along the optical axis in the lens barrel, and the focal length of the zoom lens can be continuously changed from a wide angle to a long focus through the common movement of the zoom lens group G2 and the focusing lens group G4, so that the high image quality of the zoom lens at each focal position is ensured.

Table 5 details specific optical physical parameters of each lens in the zoom lens according to the second embodiment of the present invention in one possible implementation.

Table 5 design values of optical physical parameters of zoom lens

The surface numbers in table 5 are numbered according to the surface order of the lenses, for example, the surface number "1" represents the object side surface of the first lens L1, the surface number "2" represents the image side surface of the first lens L1, and so on; "STO" represents a stop of the zoom lens; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents the surface curved to the image plane side, a negative value represents the surface curved to the object plane side, where "INF" represents the surface as a plane and the radius of curvature is infinity; thickness represents the center axial distance from the current surface to the next surface, and the unit of curvature radius and thickness are millimeters (mm); material (nd) represents the refractive index, i.e. the ability of the material between the current surface and the next surface to deflect light, and space represents the current position as air, with a refractive index of 1; the material (vd) represents abbe number (also called abbe number), i.e. the dispersion characteristic of the material from the current surface to the next surface for light, and the blank represents the current position as air; the half-aperture represents the corresponding half-height of the light on the surface of each lens.

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

Table 6 design values of zoom intervals of zoom lenses

The zoom interval in table 6 is an interval value at which the zoom lens is different at the wide angle end and the telephoto end.

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

wherein Z is the axial distance from the curved surface at the position perpendicular to the optical axis and with the height r to the vertex of the curved surface along the optical axis direction; c represents the curvature at the apex of the aspherical surface;、/>、/>、/>、/>、/>、/>、/>and->High-order aspheric coefficients of fourth order, sixth order, eighth order, tenth order, fourteen order, sixteen order, eighteen order and twenty order corresponding to the aspheric surface>Combining into high order terms corresponding to the aspherical surface.

Table 7 details the aspherical coefficients of the lenses in this example two in one possible implementation, by way of example.

Table 7 design values of aspherical coefficients of each lens in zoom lens

The zoom lens of the second embodiment achieves the following technical indexes:

table 8 technical index of zoom lens

Further, fig. 23 is a graph of chromatic aberration of a zoom lens at a wide angle end provided in the second embodiment of the present invention, and fig. 24 is a graph of chromatic aberration of a zoom lens at a telephoto end provided in the second embodiment of the present invention, wherein, as shown in fig. 23 and 24, a vertical direction indicates normalization of an aperture, 0 indicates on an optical axis, and a vertex in the vertical direction indicates a maximum pupil radius; the dominant wavelength was 546.07nm and the horizontal direction represents the offset from the dominant wavelength in micrometers (μm). The maximum field of view in fig. 23 and 24 is 6.55 millimeters. As can be seen from fig. 23 and 24, when the zoom lens is at the wide-angle end, the chromatic aberration of the vertical axis of different wavelengths is controlled within a (-2 μm, +3 μm) range; when the zoom lens is at the long focal end, the vertical chromatic aberration of different wavelengths is controlled within (-7 mu m, +1.5 mu m), which indicates that the vertical chromatic aberration of the zoom lens at the wide angle end and the long focal end is better controlled, and the wide spectrum application requirement of the whole wave band can be met.

Fig. 25 to fig. 31 are light ray fan diagrams of the zoom lens provided in the second embodiment of the present invention at different angles of view at the wide angle end, and fig. 32 to fig. 38 are light ray fan diagrams of the zoom lens provided in the second embodiment of the present invention at different angles of view at the telephoto end, where the abscissa indicates the normalized beam caliber and the ordinate indicates the chromatic aberration, as shown in fig. 25 to fig. 38. Ideally, each curve is completely coincident with the abscissa axis, and all light rays in the field of view are focused on the same point on the image plane; the ordinate in the image may also be expressed as the maximum extent of dispersion of the light beam in the ideal plane. The light fan graph can reflect monochromatic aberration with different wavelengths and also can show the magnitude of vertical axis chromatic aberration. The maximum scale in FIGS. 25-38 is + -30 μm. As can be seen from fig. 25 to 38, the zoom lens has better wavelengths close to the abscissa under each field of view, which indicates that the chromatic aberration of each wavelength is better corrected. In addition, the curves of all colors are not obviously dispersed, so that the zoom lens has better correction on chromatic aberration, and the imaging requirement of clear imaging of the full wave band of the zoom lens is ensured.

Fig. 39 is a field curvature distortion diagram of a zoom lens at a wide angle end according to a second embodiment of the present invention, and fig. 40 is a field curvature distortion diagram of a zoom lens at a telephoto end according to a second embodiment of the present invention, as shown in fig. 39 and 40, in a left coordinate system of the drawings, a horizontal coordinate represents a magnitude of a field curvature of the zoom lens in mm; the vertical coordinates represent the normalized image height without units; in the right coordinate system, the horizontal coordinate represents the magnitude of distortion (F-Tan (Theta)) in units of; the vertical coordinates represent the normalized image height without units; the maximum field of view in fig. 39 is 25.706 degrees and the maximum field of view in fig. 40 is 7.455 degrees. As can be seen from fig. 39 and 40, the zoom lens provided in the present embodiment is effectively controlled in field curvature from light having a wavelength of 436nm to light having a wavelength of 870nm at the wide angle end and the telephoto end, that is, the difference between the image quality at the center and the image quality at the periphery is small at the time of imaging. Meanwhile, the distortion of the zoom lens at the wide angle end is within-8% -1%, and the distortion of the zoom lens at the tele end is within-0.5% -3%, so that the distortion of the zoom lens at the wide angle end and the tele end provided by the embodiment is well corrected, and the imaging distortion is small.

Example III

Fig. 41 is a schematic view of a zoom lens according to a third embodiment of the present invention at a wide angle end, fig. 42 is a schematic view of a zoom lens according to a third embodiment of the present invention at a telephoto end, and as shown in fig. 41 and 42, the zoom lens according to the third embodiment of the present invention includes a first fixed lens group G1, a zoom lens group G2, a stop STO, a second fixed lens group G3, a focusing lens group G4, and a third fixed lens group G5 sequentially arranged from an object plane to an image plane along an optical axis, where the first fixed lens group G1, the second fixed lens group G3, and the third fixed lens group G5 are fixedly disposed, and the zoom lens group G2 and the focusing lens group G4 are movably disposed along the optical axis direction. The first fixed lens group G1 includes a first lens L1, a second lens L2, and a third lens L3, which are sequentially arranged from an object plane to an image plane. The zoom lens group G2 includes a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7, which are arranged in order from the object plane to the image plane. The second fixed lens group G3 includes an eighth lens L8, a ninth lens L9, a tenth lens L10, an eleventh lens L11, and a twelfth lens L12, which are arranged in order from the object plane to the image plane. The focus lens group G4 includes a thirteenth lens L13, a fourteenth lens L14, a fifteenth lens L15, and a sixteenth lens L16, which are arranged in order from the object plane to the image plane. The third fixed lens group G5 includes a seventeenth lens L17. And a piece of plate glass CG is further arranged along the object plane to the image plane, the plate glass CG is positioned on one side of the image side surface of the seventeenth lens L17, and the plate glass CG can protect a photosensitive chip in the imaging sensor.

In the zoom lens provided in the present embodiment, the first fixed lens group G1, the zoom lens group G2, the second fixed lens group G3, the focus lens group G4, and the third fixed lens group G5 may be disposed in one barrel (not shown in fig. 21 and 22). The first fixed lens group G1, the second fixed lens group G3 and the third fixed lens group G5 are fixed in position in the lens barrel, the zoom lens group G2 and the focusing lens group G4 can reciprocate along the optical axis in the lens barrel, and the focal length of the zoom lens can be continuously changed from a wide angle to a long focus through the common movement of the zoom lens group G2 and the focusing lens group G4, so that the high image quality of the zoom lens at each focal position is ensured.

Table 9 details specific optical physical parameters of each lens in the zoom lens according to the third embodiment of the present invention in one possible implementation.

Table 9 design values of optical physical parameters of zoom lens

The surface numbers in table 9 are numbered according to the surface order of the lenses, for example, the surface number "1" represents the object side surface of the first lens L1, the surface number "2" represents the image side surface of the first lens L1, and so on; "STO" represents a stop of the zoom lens; the radius of curvature represents the degree of curvature of the lens surface, a positive value represents the surface curved to the image plane side, a negative value represents the surface curved to the object plane side, where "INF" represents the surface as a plane and the radius of curvature is infinity; thickness represents the center axial distance from the current surface to the next surface, and the unit of curvature radius and thickness are millimeters (mm); material (nd) represents the refractive index, i.e. the ability of the material between the current surface and the next surface to deflect light, and space represents the current position as air, with a refractive index of 1; the material (vd) represents abbe number (also called abbe number), i.e. the dispersion characteristic of the material from the current surface to the next surface for light, and the blank represents the current position as air; the half-aperture represents the corresponding half-height of the light on the surface of each lens.

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

Table 10 design values of zoom intervals of zoom lenses

The zoom interval in table 10 is an interval value at which the zoom lens is different at the wide angle end and the telephoto end.

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

wherein Z is the axial distance from the curved surface at the position perpendicular to the optical axis and with the height r to the vertex of the curved surface along the optical axis direction; c represents the curvature at the apex of the aspherical surface;、/>、/>、/>、/>、/>、/>、/>and->High-order aspheric coefficients of fourth order, sixth order, eighth order, tenth order, fourteen order, sixteen order, eighteen order and twenty order corresponding to the aspheric surface>Combining into high order terms corresponding to the aspherical surface.

Table 11 details the aspherical coefficients of the lenses in this example three, by way of example, in one possible implementation.

Table 11 design values of aspherical coefficients of each lens in zoom lens

The zoom lens of the third embodiment achieves the following technical indexes:

table 12 technical index of zoom lens

Further, fig. 43 is a graph of chromatic aberration of a zoom lens at a wide angle end provided by the third embodiment of the present invention, and fig. 44 is a graph of chromatic aberration of a zoom lens at a telephoto end provided by the third embodiment of the present invention, wherein, as shown in fig. 43 and 44, a vertical direction indicates normalization of an aperture, 0 indicates on an optical axis, and a vertical axis direction vertex indicates a maximum pupil radius; the dominant wavelength is 656.27nm and the horizontal direction represents the offset from the dominant wavelength in micrometers (μm). The maximum field of view in fig. 43 is 11.3319 Deg and the maximum field of view in fig. 44 is 2.2211 Deg. As can be seen from fig. 43 and 44, when the zoom lens is at the wide-angle end, the chromatic aberration of the vertical axis of different wavelengths is controlled within a (-3 μm, +2 μm) range; when the zoom lens is at the tele end, the vertical axis chromatic aberration of different wavelengths is controlled within (-2 mu m, +2 mu m), which indicates that the vertical axis chromatic aberration of the zoom lens at the wide angle end and the tele end is better controlled, and the wide spectrum application requirement of the whole wave band can be met.

Fig. 45 to 52 are light ray fan diagrams of the zoom lens according to the third embodiment of the present invention at different angles of view at the wide angle end, and fig. 53 to 60 are light ray fan diagrams of the zoom lens according to the third embodiment of the present invention at different angles of view at the telephoto end, where the abscissa indicates the normalized beam caliber and the ordinate indicates the chromatic aberration, as shown in fig. 45 to 60. Ideally, each curve is completely coincident with the abscissa axis, and all light rays in the field of view are focused on the same point on the image plane; the ordinate in the image may also be expressed as the maximum extent of dispersion of the light beam in the ideal plane. The light fan graph can reflect monochromatic aberration with different wavelengths and also can show the magnitude of vertical axis chromatic aberration. The maximum scale in FIGS. 45-60 is 50 μm. As can be seen from fig. 45 to 60, the zoom lens has better wavelengths close to the abscissa under each field of view, which indicates that the chromatic aberration of each wavelength is better corrected. In addition, the curves of all colors are not obviously dispersed, so that the zoom lens has better correction on chromatic aberration, and the imaging requirement of clear imaging of the full wave band of the zoom lens is ensured.

Fig. 61 is a field curvature distortion diagram of a zoom lens at a wide angle end according to a third embodiment of the present invention, and fig. 62 is a field curvature distortion diagram of a zoom lens at a telephoto end according to a third embodiment of the present invention, as shown in fig. 61 and 62, in a left coordinate system of the drawings, a horizontal coordinate represents a magnitude of a field curvature of the zoom lens in mm; the vertical coordinates represent the normalized image height without units; in the right coordinate system, the horizontal coordinate represents the magnitude of distortion (F-Tan (Theta)) in units of; the vertical coordinates represent the normalized image height without units; the maximum field of view in fig. 61 is 11.332 degrees and the maximum field of view in fig. 62 is 2.221 degrees. As can be seen from fig. 61 and 62, the zoom lens provided in the present embodiment is effectively controlled in field curvature from light having a wavelength of 436nm to light having a wavelength of 1000nm at the wide angle end and the telephoto end, that is, the difference between the image quality at the center and the image quality at the periphery is small at the time of imaging. Meanwhile, the distortion of the zoom lens at the wide angle end is within-2%, and the distortion of the zoom lens at the tele end is within-1% -4%, so that the distortion of the zoom lens at the wide angle end and the tele end provided by the embodiment is well corrected, and the imaging distortion is small.

For a clearer description of the above embodiments, table 13 details specific optical physical parameters of each lens in the zoom lenses provided in embodiments one to three of the present invention.

Table 13 design values of optical physical parameters of zoom lens

The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims (9)

1. The zoom lens is characterized by comprising a first fixed lens group, a zoom lens group, a diaphragm, a second fixed lens group, a focusing lens group and a third fixed lens group which are sequentially arranged from an object plane to an image plane along an optical axis;

the first fixed lens group, the second fixed lens group and the third fixed lens group are fixedly arranged, and the zoom lens group and the focusing lens group are movably arranged along the optical axis direction;

the first fixed lens group has positive focal power, the zoom lens group has negative focal power, the second fixed lens group has positive focal power, the focusing lens group has positive focal power, and the third fixed lens group has negative focal power;

The first fixed lens group consists of a first lens, a second lens and a third lens which are sequentially arranged from an object surface to an image surface; the first lens has negative focal power, the second lens has positive focal power, and the third lens has positive focal power;

the zoom lens group consists of a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged from an object surface to an image surface; the fourth lens has negative focal power, the fifth lens has negative focal power, the sixth lens has positive focal power, and the seventh lens has negative focal power;

the second fixed lens group consists of an eighth lens, a ninth lens, a tenth lens, an eleventh lens and a twelfth lens which are sequentially arranged from the object surface to the image surface; the eighth lens has positive optical power, the ninth lens has negative optical power, the tenth lens has positive optical power, the eleventh lens has negative optical power, and the twelfth lens has positive or negative optical power;

the focusing lens group consists of a thirteenth lens, a fourteenth lens, a fifteenth lens and a sixteenth lens which are sequentially arranged from an object surface to an image surface; the thirteenth lens has positive or negative optical power, the fourteenth lens has positive optical power, the fifteenth lens has positive optical power, and the sixteenth lens has positive or negative optical power;

The third fixed lens group includes only a seventeenth lens having negative optical power;

the focal length of the zoom lens at the wide angle end is FW, and the focal length of the zoom lens at the telephoto end is FT, wherein FT/FW is more than or equal to 3.3 and less than or equal to 3.4.

2. The zoom lens of claim 1, wherein the lens is formed of a lens material having a refractive index,

at least one of the seventh lens, the twelfth lens, the thirteenth lens, the fifteenth lens, and the seventeenth lens is an aspherical lens.

3. The zoom lens of claim 1, wherein the lens is formed of a lens material having a refractive index,

the fifth lens and the sixth lens form a cemented lens group.

4. The zoom lens of claim 1, wherein the lens is formed of a lens material having a refractive index,

at least two of the eighth lens, the ninth lens, the tenth lens, the eleventh lens, and the twelfth lens constitute a cemented lens group.

5. The zoom lens of claim 4, wherein the lens is configured to,

at least two of the ninth lens, the tenth lens, and the eleventh lens constitute the cemented lens group;

and the total focal length of the ninth lens, the tenth lens and the eleventh lens is F, and the focal length of the zoom lens at the long focal end is FT, wherein F/FT is more than or equal to 1.32 and less than or equal to 66.5.

6. The zoom lens of claim 1, wherein the lens is formed of a lens material having a refractive index,

the focal length of the first fixed lens group is F1, the focal length of the zoom lens group is F2, the focal length of the second fixed lens group is F3, the focal length of the focusing lens group is F4, the focal length of the third fixed lens group is F5, the focal length of the zoom lens at the wide-angle end is FW, wherein,

3.544≤F1/FW≤3.681；-1.155≤F2/FW≤-1.057；1.746≤F3/FW≤1.778；

1.537≤F4/FW≤2.179；-42.359≤F5/FW≤-1.798。

7. the zoom lens of claim 1, wherein the lens is formed of a lens material having a refractive index,

the maximum movable distance of the zoom lens group is S2, and the maximum movable distance of the focusing lens group is S4, wherein S2/S4 is more than or equal to 4.044 and less than or equal to 4.680.

8. The zoom lens of claim 1, wherein the lens is formed of a lens material having a refractive index,

the refractive index of the sixth lens is nd6, and the Abbe number is vd6; the refractive index of the seventh lens is nd7, and the Abbe number is vd7; the refractive index of the ninth lens is nd9, and the Abbe number is vd9; the refractive index of the tenth lens is nd10, and the Abbe number is vd10; the refractive index of the eleventh lens is nd11, and the Abbe number is vd11; the refractive index of the sixteenth lens is nd16, and the Abbe number is vd16; the refractive index of the seventeenth lens is nd17, and the Abbe number is vd17; wherein,

2.00≤nd6≤2.05；25.47≤vd6≤28.47；

1.54≤nd7≤1.57；59.80≤vd7≤83.35；

1.64≤nd9≤1.70；47.55≤vd9≤58.73；

1.44≤nd10≤1.59；69.20≤vd10≤95.12；

1.80≤nd11≤1.85；30.39≤vd11≤36.00；

1.53≤nd16≤1.54；57.83≤vd16≤70.70；

1.54≤nd17≤1.57；47.20≤vd17≤70.00。

9. the zoom lens of claim 1, wherein the lens is formed of a lens material having a refractive index,

The total optical length of the zoom lens is TTL, the maximum movable distance of the zoom lens group is S2, the maximum movable distance of the focusing lens group is S4, wherein,

3.800≤TTL/S2≤4.32；16.5≤TTL/S4≤18.05。