CN114415342A

CN114415342A - Zoom lens and terminal equipment

Info

Publication number: CN114415342A
Application number: CN202210296197.2A
Authority: CN
Inventors: 朱松河; 王新权; 武斌; 余洋华
Original assignee: Honor Device Co Ltd
Current assignee: Honor Device Co Ltd
Priority date: 2022-03-24
Filing date: 2022-03-24
Publication date: 2022-04-29
Anticipated expiration: 2042-03-24
Also published as: CN114415342B

Abstract

The embodiment of the application discloses a zoom lens and terminal equipment, wherein the terminal equipment comprises the zoom lens, and the terminal equipment can be specifically terminal equipment with an imaging function, such as a mobile phone, a camera, a smart watch and the like. In the direction from the object side to the image side, the zoom lens sequentially comprises a first lens group, a first focusing group, a second lens group, a second focusing group, a third lens group and a fourth lens group, and the first lens group, the second lens group, the third lens group and the fourth lens group all comprise at least one lens; the first lens group has negative focal power, and the focal power of the rest lens groups is not limited; the first focusing group and the second focusing group both comprise at least one focusing element; the effective focal length of the zoom lens in a telephoto state can be recorded as FT, the effective focal length of the zoom lens in a wide angle state can be recorded as FW, and the following relationship exists between FT and FW: FT/FW is not less than 1.5. The zoom lens can realize continuous zooming and has simple structure and high compactness.

Description

Zoom lens and terminal equipment

Technical Field

The application relates to the field of optical lenses, in particular to a zoom lens and terminal equipment.

Background

In recent years, with rapid development and rapid popularization of terminal devices in the form of smart phones and the like, performance requirements of users on the terminal devices are also increasing, wherein requirements on photographing levels and imaging quality under different scenes increasingly attract attention of consumers, and therefore, zoom camera shooting technology is beginning to be widely applied to the terminal devices. However, the zoom imaging technique adopted by the conventional terminal device generally performs zooming by switching a plurality of lenses, and is not continuous zooming in a true sense.

Therefore, how to provide a solution to overcome the above-mentioned drawbacks is still a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The embodiment of the application provides a zoom lens and terminal equipment, wherein the zoom lens can realize continuous zooming.

In a first aspect, an embodiment of the present application provides a zoom lens, which is applicable to a mobile phone, a camera, a smart watch, and other terminal devices having an imaging function. The zoom lens sequentially comprises a first lens group, a first focusing group, a second lens group, a second focusing group, a third lens group and a fourth lens group from the object side to the image side. The first lens group, the second lens group, the third lens group and the fourth lens group each include at least one lens; when a plurality of lenses are used, the lenses are joined by a gluing process. The first lens group has negative focal power, and the focal power of the rest lens groups is not limited. The first focusing group and the second focusing group both comprise at least one focusing element, and the focusing elements are liquid focusing elements. The effective focal length of the zoom lens in a telephoto state can be recorded as FT, the effective focal length of the zoom lens in a wide angle state can be recorded as FW, and the following relationship exists between FT and FW: FT/FW is not less than 1.5.

By adopting the structure, the first lens group has negative focal power, which is beneficial to ensuring that light rays can smoothly enter the zoom lens; the first focusing group is mainly used for changing the focal length of the lens so as to realize the zooming function; the second lens group is used for correcting aberration introduced by the first focusing group; the second focusing group is mainly used for compensating image plane deviation caused by zooming; the third lens group can be used for optimizing the chromatic aberration of the lens and improving the performance of the lens; the fourth lens group is used for correcting the aberration of the tail end of the lens and improving the performance of the lens. The focusing elements in the two focusing groups can be liquid focusing elements, the liquid focusing elements can realize continuous zooming, the total optical length TTL of the zoom lens is not changed, the compactness is improved, and conditions are provided for popularization and application of the zoom lens in scenes with limited installation space, such as mobile phones.

Further, the following relationship exists between the effective focal length FT of the zoom lens in the telephoto state and the effective focal length FW of the zoom lens in the wide angle state: FT/FW is more than or equal to 1.5, which is beneficial to ensuring that the zoom lens provided by the embodiment of the application has good imaging quality under different scenes.

Therefore, the embodiment of the application can better realize continuous zooming by matching the four lens groups and the two focusing groups, has small quantity of lens combination focusing groups and simple structure, and simultaneously has the advantages of compact structure, high imaging quality and the like.

Based on the first aspect, embodiments of the present application provide the first implementation manner of the first aspect, and at least one lens of the first lens group, the second lens group, the third lens group, and the fourth lens group is an aspheric lens.

Compared with a spherical lens with constant curvature, the aspherical lens has better curvature radius characteristic and adjustable characteristic, is beneficial to reducing spherical aberration and improving focusing level, and can improve distortion aberration and chromatic dispersion aberration, thereby improving imaging quality. Moreover, aspheric lenses can reduce the total number of lenses required to achieve a given result, and also contribute to reducing the overall weight and axial size of the lens.

Based on the first aspect or based on the first implementation manner of the first aspect, this application provides a second implementation manner of the first aspect, the effective focal length of the first lens group may be denoted as F1, the effective focal length of the zoom lens in a telephoto state may be denoted as FT, and the following relationship exists between F1 and FT: -5.5< F1/FT < -1.5. Therefore, the optical path is favorably and reasonably distributed, and the optical path outside the field of view can be effectively prevented from reaching the effective image surface to influence the imaging performance.

Based on the first aspect, or based on the first implementation mode or the second implementation mode of the first aspect, this application provides an example of the third implementation mode of the first aspect, where a radius of curvature of an object-side surface of the first lens group may be denoted as R11, a radius of curvature of an image-side surface of the first lens group may be denoted as R12, and the following relationship exists between R11 and R12: 0.6 < R11/R12 < 0.9. Therefore, the shape of the first lens group can be effectively restrained, light rays entering the lens can be controlled, lens aberration can be balanced, and imaging quality of the system can be improved.

Based on the first aspect, or based on any one of the first to third implementations of the first aspect, an example of the present application further provides a fourth implementation of the first aspect, where an effective focal length of the first focus group in the wide-angle state may be denoted as LEFW1, an effective focal length of the first focus group in the telephoto state may be denoted as LEFT1, and the following relationship may exist between the LEFW1 and the LEFT 1: 1 < | LEFW1/LEFT1| < 4.5. Therefore, the change of the focal power of the first focusing group can be controlled within a reasonable range, and the zoom lens is beneficial to stable work.

Based on the first aspect or any one of the first to fourth embodiments of the first aspect, the present application provides an example of a fifth embodiment of the first aspect, a distance between an image side surface of the first lens group and an object side surface of the second lens group in the optical axis direction may be denoted as D12, a distance between the image side surface of the second lens group and an object side surface of the third lens group in the optical axis direction may be denoted as D23, a total optical length of the zoom lens may be denoted as TTL, and the following relationships may exist between D12, D23 and TTL: (D12 + D23)/TTL is more than or equal to 0.3. So set up, be favorable to first battery of lens, second battery of lens, third battery of lens and two focusing group rationally arranging in optical axis direction position, have better manufacturability, be favorable to manufacturing.

Based on the first aspect, or based on any one of the first implementation manner to the fifth implementation manner of the first aspect, an example of the present application further provides a sixth implementation manner of the first aspect, an effective focal length of the second focusing group in the wide-angle state may be denoted as LEFW2, an effective focal length of the second focusing group in the telephoto state may be denoted as LEFT2, and the following relationship may exist between the LEFW2 and the LEFT 2: 1 < | LEFW2/LEFT2| < 2. Therefore, the change of the focal power of the second focusing group can be controlled within a reasonable range, and the zoom lens is beneficial to stable work.

In accordance with the first aspect or in accordance with any one of the first to sixth embodiments of the first aspect, the present examples further provide a seventh embodiment of the first aspect, in which the third lens group includes a third lens and a fourth lens, and the third lens and the fourth lens are adhesively bonded; the effective focal length of the fourth lens may be denoted as F4, the effective focal length of the third lens may be denoted as F3, and the following relationship may exist between F4 and F3: -2.5 < F4/F3 < -1. Therefore, the focal power of each lens of the third lens group can be reasonably distributed, the system aberration can be effectively improved, and the imaging quality is improved.

Based on the first aspect or any one of the first to seventh implementations of the first aspect, an example of the present application further provides an eighth implementation of the first aspect, a distance between the third lens group and the fourth lens group in the optical axis direction may be denoted as D45, a total optical length of the zoom lens may be denoted as TTL, and the following relationship may exist between D45 and TTL: D45/TTL is less than or equal to 0.1. Therefore, the total length of the lens can be effectively reduced, and the miniaturization design of the lens is facilitated.

Based on the first aspect, or based on any one of the first implementation manner to the eighth implementation manner of the first aspect, this application example further provides a ninth implementation manner of the first aspect, where the total optical length of the zoom lens may be denoted as TTL, an effective focal length of the zoom lens in a telephoto state may be denoted as FT, and the TTL and FT may have the following relationship: TTL/FT < 1.8. Therefore, the lens has good long-focus characteristic, the total length of the system can be reduced well, and the miniaturization of the module is realized.

With reference to the first aspect or any one of the first to ninth implementation manners of the first aspect, an embodiment of the present application further provides a tenth implementation manner of the first aspect, where the zoom lens further includes a stop, and the stop is disposed between the first focusing group and the second lens group. The arrangement of the diaphragm can limit the range of light beams, so that the difference of the aperture of the lens before and after the diaphragm can be balanced; moreover, the diaphragm is arranged at the position, so that the lens can have a larger diaphragm, and the performance requirement of the zoom lens for large diaphragm can be met.

With reference to the first aspect or any one of the first to tenth embodiments of the first aspect, the present application provides an eleventh embodiment of the first aspect, and the foregoing zoom lens further includes a filter disposed on a side of the fourth lens group facing away from the third lens group. The optical filter can filter out light beams in specified wave bands, and further can highlight light beams in other wave bands, so that imaging is more vivid.

Based on the first aspect, or based on any one of the first implementation manner to the eleventh implementation manner of the first aspect, an embodiment of the present application further provides a twelfth implementation manner of the first aspect, where the filter may be an infrared cut filter to filter infrared light in an infrared region, so that picture distortion caused by the infrared light may be reduced, and a color image with higher quality may be obtained.

In practice, the kinds of the optical filters may be various, which is particularly associated with practical application scenarios of the zoom lens, and the like. For example, the filter may also be a monochromatic filter, so that the amount of incident light may be increased to obtain a clearer image, and this embodiment is particularly suitable for use in scenes with low illuminance, such as night vision, for example.

Based on the second aspect, an embodiment of the present application provides a terminal device, which may specifically be a terminal device with an imaging function, such as a mobile phone, a video camera, a smart watch, and the like, and includes a body and a camera module, where the camera module includes a lens, and the lens may be the zoom lens according to any implementation manner of the foregoing first aspect. Since the zoom lens in the first aspect has the above technical effects, the terminal device having the zoom lens also has similar technical effects, and therefore, the detailed description thereof is omitted here.

Drawings

Fig. 1 is a front view of a specific implementation of a terminal device provided in an embodiment of the present application;

FIG. 2 is a rear elevational view of FIG. 1;

FIG. 3 is a schematic structural diagram of a zoom lens according to an embodiment of the present application in a wide-angle state;

FIG. 4 is a graph showing a curvature of field characteristic of the zoom lens of FIG. 3;

FIG. 5 is a graph showing distortion characteristics of the zoom lens of FIG. 3;

FIG. 6 is a schematic structural diagram of a zoom lens according to an embodiment of the present application in a telephoto state;

FIG. 7 is a graph showing a curvature of field characteristic of the zoom lens of FIG. 6;

FIG. 8 is a graph showing distortion characteristics of the zoom lens of FIG. 6;

FIG. 9 is a schematic structural diagram of a zoom lens system according to a second embodiment of the present application in a wide-angle state;

fig. 10 is a graph of curvature of field characteristics of the zoom lens of fig. 9;

fig. 11 is a graph showing distortion characteristics of the zoom lens of fig. 9;

FIG. 12 is a schematic structural diagram of a zoom lens according to a second embodiment of the present application in a telephoto state;

fig. 13 is a graph of curvature of field characteristics of the zoom lens of fig. 12;

fig. 14 is a graph showing distortion characteristics of the zoom lens of fig. 12;

FIG. 15 is a schematic structural diagram of a zoom lens system according to a third embodiment of the present application in a wide-angle state;

fig. 16 is a graph of curvature of field characteristics of the zoom lens of fig. 15;

fig. 17 is a graph showing distortion characteristics of the zoom lens of fig. 15;

FIG. 18 is a schematic structural diagram of a zoom lens according to a third embodiment of the present application in a telephoto state;

fig. 19 is a graph of curvature of field characteristics of the zoom lens of fig. 18;

fig. 20 is a graph showing distortion characteristics of the zoom lens of fig. 18;

FIG. 21 is a schematic structural diagram of a fourth implementation of a zoom lens system provided in an embodiment of the present application in a wide-angle state;

fig. 22 is a graph of curvature of field characteristics of the zoom lens of fig. 21;

fig. 23 is a graph showing distortion characteristics of the zoom lens of fig. 21;

FIG. 24 is a schematic structural diagram of a fourth implementation manner of a zoom lens according to an embodiment of the present application in a telephoto state;

fig. 25 is a graph of curvature of field characteristics of the zoom lens of fig. 24;

fig. 26 is a graph showing distortion characteristics of the zoom lens of fig. 24;

FIG. 27 is a schematic structural diagram of a fifth implementation manner of a zoom lens according to an embodiment of the present application in a wide-angle state;

fig. 28 is a graph of curvature of field characteristics of the zoom lens of fig. 27;

fig. 29 is a graph showing distortion characteristics of the zoom lens of fig. 27;

FIG. 30 is a schematic structural diagram of a zoom lens according to a fifth implementation manner in a telephoto state according to an embodiment of the present application;

fig. 31 is a graph of curvature of field characteristics of the zoom lens of fig. 30;

FIG. 32 is a graph showing distortion characteristics of the zoom lens of FIG. 30;

FIG. 33 is a schematic structural diagram illustrating a wide-angle state of a sixth implementation of a zoom lens system provided by an embodiment of the present application;

fig. 34 is a graph of curvature of field characteristics of the zoom lens of fig. 33;

FIG. 35 is a graph showing distortion characteristics of the zoom lens of FIG. 33;

FIG. 36 is a schematic structural diagram of a sixth implementation of a zoom lens system provided in an embodiment of the present application in a telephoto state;

fig. 37 is a graph of curvature of field characteristics of the zoom lens of fig. 36;

fig. 38 is a distortion characteristic graph of the zoom lens in fig. 36.

The reference numerals in fig. 1-38 are illustrated as follows:

100 terminal equipment, 101 shells, 102 display screens, 103 camera modules and 104 protective lenses;

the focusing lens comprises a first lens 1, a first focusing group 2, a second lens 3, a second focusing group 4, a third lens group 5, a third lens 51, a fourth lens 52, a fifth lens 6, a diaphragm 7 and an optical filter 8.

Detailed Description

In order to make the technical solutions of the present application better understood by those skilled in the art, the present application is further described in detail with reference to the accompanying drawings and specific embodiments.

For convenience of understanding, some technical terms referred to in the embodiments of the present application are explained and described below.

The optical axis, which is the direction of the optical system conducting light, refers to the chief ray of the central field of view. For a symmetric transmission system, it is generally coincident with the optical system rotation centerline.

Focal length, also known as 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 when an object at infinity is imaged through the lens at the focal plane. For a fixed-focus lens, the position of the optical center is fixed and unchanged, so that the focal length is fixed; for a zoom lens, a change in the optical center of the lens results in a change in the focal length of the lens, and thus the focal length can be adjusted.

The optical power, equal to the difference between the image-side and object-side beam convergence, characterizes the ability of the optical system to deflect light. When the refractive index of air is considered to be 1 by approximation, the general optical power is expressed as the inverse of the image-side focal length.

The side of the lens near the object side is the object side, and the surface of the lens near the object side can be referred to as the object side. The side of the lens on which the image of the object is located is the image side, and the surface of the lens close to the image side can be referred to as the image side surface.

Embodiments of the present application relate to a terminal device that may include a handheld device, an in-vehicle device, a wearable device, a computing device, or other processing device connected to a wireless modem. But may also include cellular phones, smart phones (smartphones), Personal Digital Assistants (PDAs), tablet computers, laptop computers (laptops), video cameras, video recorders, cameras, smartwatches (smartwatches), smartbands (smartbands), in-vehicle computers, and other imaging enabled terminals. In the embodiment of the present application, a specific form of the terminal device is not particularly limited, and for convenience of understanding, the following description takes the terminal device as a mobile phone as an example.

Referring to fig. 1 and fig. 2, fig. 1 is a front view of a specific implementation of a terminal device according to an embodiment of the present disclosure, and fig. 2 is a back view of fig. 1.

As shown in fig. 1, the terminal device 100 may include a housing 101, a display screen 102, and a camera module 103.

The housing 101 is formed with an accommodating space for arranging various components of the terminal device 100, such as a battery, an antenna, a circuit board, and the aforementioned camera module 103. Meanwhile, the housing 101 may also function to protect the terminal device 100. The display screen 102 may be mounted to the housing 101. In some embodiments, the housing 101 includes a back cover and a middle frame to which the display screen 102 and the camera module 103 may be secured. The material of the housing 101 may be metal, plastic, ceramic, or glass.

The display screen 102 may be a Liquid Crystal Display (LCD) screen, an Organic Light Emitting Diode (OLED) display screen, and the like, wherein the OLED display screen may be a flexible display screen or a hard display screen. The display screen 102 may be a regular screen, or may be a shaped screen, a folded screen, etc., for example, the display screen 102 may rotate and fold freely relative to each other to form an arc, a sphere, a cylinder, etc. The display screen 102 may be disposed on the front side of the terminal device 100, may be disposed on the back side of the terminal device 100, and may be disposed on both the front side and the back side of the terminal device 100. The front side of the terminal device 100 may be understood as a side facing a user when the user uses the terminal device 100, and may be specifically shown in fig. 1; the back of the terminal device 100 may be understood as the side of the user facing away from the user when using the terminal device 100, and may be specifically shown in fig. 2.

Take the front of the terminal device 100 as an example. In terms of the arrangement range, the display screen 102 may cover all areas of the front surface of the terminal device 100, that is, the terminal device 100 may form a full screen, at this time, the display screen 102 not only has a display function, but also generally has a touch function, that is, the terminal device 100 may be operated by clicking the display screen 102. Alternatively, the display screen 102 may only cover a partial area of the front surface of the terminal device 100, in this case, the display screen 102 may have a touch function, or may only have a display function; when the display function is provided only, the region of the housing 101 not provided with the display screen 102 may be provided with corresponding human-machine operation elements such as keys for operating the terminal device 100, and these human-machine operation elements may be provided at any position such as the front, back, or side of the terminal device 100.

The camera module 103 is used for capturing still images or videos. When the camera module 103 is disposed on the front side of the terminal device 100, the camera module 103 may be used to shoot a scene located on the front side of the terminal device 100, and in some embodiments, the camera module 103 located on the front side may be referred to as a front camera; the camera module 103 is disposed on the back of the terminal device 100 and can be used to shoot a scene on the back side of the terminal device 100, and in some embodiments, the camera module 103 on the back can be referred to as a rear camera. When shooting, the user can select the corresponding camera module 103 according to the shooting requirement. The camera module 103 can be used for shooting scenes at different distances, such as far, near or macro, and the embodiment of the present application is not particularly limited.

It should be understood that the mounting position of the camera head module 103 in fig. 1 is merely illustrative. When the camera module 103 is used as a front camera, it may be installed at any position on the front surface of the terminal device 100 except the display screen 102, for example, the left side of a receiver, the middle of the upper part of the terminal device 100, the lower part (or chin) of the terminal device 100, or four corners of the terminal device 100; in fact, for a full-screen mobile phone, the camera module 103 may also be located below the display screen 102. When the camera module 103 is used as a rear camera, it can be installed at any position on the back of the terminal device 100, for example, the upper left corner or the upper right corner. In other embodiments, the camera module 103 may be disposed not on the main body of the terminal device 100, but on a protruding edge relative to the main body of the terminal device 100, or on a component that is movable or rotatable relative to the terminal device 100, and the component may be retractable or rotatable from the main body of the terminal device 100, or the like. When the camera module 103 can rotate relative to the terminal device 100, the camera module 103 is equivalent to a front camera and a rear camera, that is, by rotating the same camera module 103, not only can a scene on the front side of the terminal device 100 be shot, but also a scene on the back side of the terminal device 100 can be shot. In other embodiments, for the terminal device 100 with the folding function, when the display screen 102 can be folded, the camera module 103 may be used as a front camera or a rear camera along with the folding of the display screen 102.

The number of the camera modules 103 is not limited in the embodiment of the application, and may be one, two, four or more, for example, one or more camera modules 103 may be arranged on the front side of the terminal device 100, and/or one or more camera modules 103 may be arranged on the back side of the terminal device 100. When a plurality of camera modules 103 are provided, the plurality of camera modules 103 may be identical or different, for example, the plurality of camera modules 103 have different optical parameters of lenses, different positions of lenses, different shapes of lenses, and the like. The embodiment of the application does not limit relative positions when the plurality of camera modules are arranged.

In some optional embodiments, the terminal device 100 may further include a protection lens 104 for protecting the camera module 103. The protection lens 104 is disposed on the housing 101 and covers the camera module 103. When the protective lens 104 is used to protect the front camera, the protective lens 104 may only cover the front camera module or cover the whole front surface of the terminal device 100, wherein when the protective lens 104 covers the whole front surface of the terminal device 100, the protective lens 104 may be used to protect the front camera module and the display screen 102 at the same time, and the protective lens 104 is Cover Glass (CG). When the protection lens 104 is used to protect the rear camera, the protection lens 104 may cover the entire back surface of the terminal device 100, or may be only disposed at a position corresponding to the rear camera module. The material of the protection lens 104 may be glass, sapphire, ceramic, etc., and the embodiment of the present application is not particularly limited. In some embodiments, the protection lens 104 is transparent, and light outside the terminal device 100 can enter the camera module 103 through the protection lens 104.

It should be understood that the structure illustrated in fig. 1 does not constitute a specific limitation to the terminal device 100, and the terminal device 100 may include more or less components than those illustrated, for example, the terminal device 100 may further include one or more components such as a battery, a flash, a fingerprint recognition module, a receiver, a key, a sensor, and the like, and the terminal device 100 may also be provided with a different arrangement of components than those illustrated. For convenience of understanding, the remaining components of the terminal device 100 except for the camera module 103 may also be referred to as a body, and the camera module 103 may be mounted on the body.

The traditional camera module generally adopts a lens group consisting of a plurality of lenses as an optical lens, and the motor component directly drives the lens barrel fixed with the lens group to integrally move for a certain distance or rotate for a certain angle, so that automatic focusing and/or optical anti-shaking can be realized. Some camera modules with zooming capability can also adjust the distance between lenses to change the focal length of the lens to realize optical zooming. When the lens adopting the solid lens is designed, a moving space for automatic focusing, optical anti-shake, zooming and the like needs to be reserved, and a compact structure is difficult to further realize; in addition, the total optical length TTL of the lens is also increased during the solid lens position moving process, where the total optical length TTL is a distance from an object side surface of the zoom lens to an image plane in the optical axis direction. In order to meet the demand of people for miniaturization of cameras, a new optical element, namely a liquid lens, is provided, wherein the refractive index of the lens can be dynamically adjusted or the focal length of the lens can be changed by changing the surface shape (curvature).

A liquid lens is an optical element made using one or more liquids without mechanical connections, and the internal parameters of the optical element can be changed by external control, so that auto-zooming and continuous zooming can be achieved. In addition, the position of the liquid lens does not need to be adjusted in the zooming process, so that the total optical length TTL of the lens is not changed, and conditions are provided for the compact design of the lens.

Based on this, embodiments of the present application provide a zoom lens, which includes, in order from an object side to an image side, a first lens group, a first focusing group, a second lens group, a second focusing group, a third lens group, and a fourth lens group. The first lens group has negative focal power to ensure that light rays can smoothly enter the zoom lens. The first focusing group and the second focusing group respectively comprise at least one focusing element, and the focusing elements can be the liquid lens, such as a gradual change refraction type lens, a liquid filling type lens, an electrowetting effect lens and the like, so as to realize continuous zooming, and the total optical length TTL of the zoom lens is not changed, so that the compactness is favorably improved, and conditions are provided for popularization and application of the zoom lens in scenes with limited installation space, such as mobile phones and the like. The first focusing group of the two focusing groups is mainly used for changing the focal length of the lens so as to realize the zooming function; the second focusing group is mainly used for compensating image plane deviation caused by zooming.

Further, the effective focal length FT of the zoom lens in the telephoto state and the effective focal length FW of the zoom lens in the wide-angle state have the following relationship: FT/FW is more than or equal to 1.5, which is beneficial to realizing continuous zooming and ensures that the zoom lens provided by the embodiment of the application has good imaging quality in different scenes.

The first lens group, the second lens group, the third lens group and the fourth lens group may each include at least one lens, and when a plurality of lenses are included, the lenses may be cemented to form a lens group having a specific parameter and a specific shape, so as to simplify a process of manufacturing the lens group.

As an exemplary illustration, the first lens group, the second lens group, and the fourth lens group may each include only one lens, and the third lens group may be cemented by two lenses. For convenience of description, the lens of the first lens group may be referred to as a first lens, and the first lens has negative power for ensuring smooth entrance of light; the lenses of the second lens group may be referred to as a second lens, and the second lens may have optical power for correcting aberrations introduced by the first focusing group; two lenses of the third lens group can be respectively called as a third lens and a fourth lens, and both the third lens and the fourth lens have focal power, wherein the third lens is close to the second lens, and the fourth lens is far away from the second lens; the lens of the fourth lens group can be called as a fifth lens, and the fifth lens can have focal power and is used for correcting lens end aberration and improving lens performance.

Each lens of the first lens group, the second lens group, the third lens group and the fourth lens group may be a spherical mirror. Alternatively, at least one lens may be an aspherical lens. The curvature of the aspheric lens is changed from the center of the lens to the edge of the lens, and compared with a spherical lens with constant curvature, the aspheric lens has better curvature radius characteristic and adjustable characteristic, is beneficial to reducing spherical aberration and improving focusing level, and can improve distortion aberration and chromatic dispersion aberration, thereby improving imaging quality; moreover, aspheric lenses can reduce the total number of lenses required to achieve a given result, and also contribute to reducing the overall weight and axial size of the lens. As an exemplary illustration, the second lens and the fifth lens may adopt aspheric lenses for improving lens aberration and improving imaging quality; the first lens, the third lens and the fourth lens can adopt spherical lenses, on one hand, the cost can be reduced, on the other hand, the third lens and the fourth lens can be conveniently glued and connected, and the tightness of the third lens and the fourth lens after connection is guaranteed.

Further, the zoom lens provided in the embodiment of the present application may further include an aperture, where the aperture may be disposed between the first focusing group and the second lens group, and a specific distance between the aperture and the first focusing group and a specific distance between the aperture and the second lens group are not limited herein. The arrangement of the diaphragm can limit the range of light beams, so that the difference of the aperture of the lens before and after the diaphragm can be balanced; moreover, the diaphragm is arranged at the position, so that the lens can have a larger diaphragm, and the performance requirement of the zoom lens for large diaphragm can be met.

Further, the zoom lens provided by the embodiment of the present application may further include an optical filter, and the optical filter may be disposed on a side of the fourth lens group facing away from the third lens group. The optical filter can filter out light beams in specified wave bands, and further can highlight light beams in other wave bands, so that imaging is more vivid.

Here, the embodiments of the present application do not limit the kind of the optical filter, and in a specific practice, those skilled in the art may configure the optical filter according to actual needs. For example, the optical filter may be an infrared cut filter to filter infrared light in an infrared region range, so that image distortion caused by infrared light can be reduced, and a color image with higher quality can be obtained; alternatively, a monochromatic filter may be used as the filter, so that the amount of light entering can be increased to obtain a clearer image, and this embodiment is particularly suitable for use in a scene with low illuminance such as at night.

With respect to the zoom lens according to each of the above embodiments, the following embodiments of the present application will also give preferable conditions to some parameters of the zoom lens to improve the performance of the zoom lens according to the embodiments of the present application to a greater extent.

In some alternative embodiments, the following relationship may exist between the effective focal length F1 of the first lens and the effective focal length FT of the zoom lens in the telephoto state: -5.5< F1/FT < -1.5, so as to be beneficial to reasonably distributing the optical power adjusting optical path, and effectively avoiding the optical path outside the field of view from reaching the effective image plane and influencing the imaging performance.

In some alternative embodiments, the following relationship may exist between the radius of curvature R11 of the object-side surface of the first lens and the radius of curvature R12 of the image-side surface of the first lens: 0.6 < R11/R12 <0.9, so as to effectively restrict the shape of the first lens, control the light rays entering the lens, be beneficial to balancing the aberration of the lens and further improve the imaging quality of the system.

In some alternative embodiments, the following relationship may exist between the effective focal length LEFW1 of the first focus group in the wide state and the effective focal length LEFT1 of the first focus group in the tele state: 1 < | LEFW1/LEFT1| <4.5, so that the power change of the first focusing group is controlled within a reasonable range, and the stable work of the zoom lens is facilitated.

In some alternative embodiments, the following relationship may exist between the effective focal length LEFW2 of the second focus group in the wide state and the effective focal length LEFT2 of the second focus group in the tele state: 1 < | LEFW2/LEFT2| <2 so as to control the power change of the second focusing group within a reasonable range, which is beneficial to the stable work of the zoom lens.

In some alternative embodiments, there may be a following relationship between an image-side surface of the first lens group (for embodiments including only one lens, that is, the first lens) and an object-side surface of the second lens group (for embodiments including only one lens, that is, the second lens) in the optical axis direction, a spacing D12 between the image-side surface of the second lens group (for embodiments including only one lens, that is, the second lens) and an object-side surface of the third lens group (for embodiments including the third lens and the fourth lens, that is, the third lens) in the optical axis direction, a spacing D23 between the image-side surface of the second lens group and the object-side surface of the third lens group (for embodiments including the third lens and the fourth lens, that is, the third lens), and a total optical length TTL of the zoom lens: (D12 + D23)/TTL is more than or equal to 0.3. So set up, be favorable to first lens, second lens, third lens and two focusing groups to rationally arrange in optical axis direction position, have better manufacturability, be favorable to manufacturing.

In some alternative embodiments, the following relationship may exist between the effective focal length F4 of the fourth lens and the effective focal length F3 of the third lens: 2.5 < F4/F3 < -1, which is beneficial to reasonably distributing the focal power of each lens of the third lens group, and can effectively improve the system aberration and improve the imaging quality.

In some alternative embodiments, there may be a following relationship between a distance D45 in the optical axis direction of the third lens group and the fourth lens group and a total optical length TTL of the zoom lens: D45/TTL is less than or equal to 0.1, so that the total length of the lens is effectively reduced, and the miniaturization design of the lens is facilitated.

In some alternative embodiments, the following relationship may exist between the total optical length TTL of the zoom lens and the effective focal length FT of the zoom lens in the telephoto state: TTL/FT is less than 1.8, which is beneficial to ensuring that the lens has good long focus characteristic, and simultaneously can better reduce the total length of the system and realize the miniaturization of the module.

In summary, the embodiment of the present application adopts two focusing groups and four lens groups, and cooperates with the foregoing various condition designs, and through reasonable power distribution and optical performance optimization, the continuous zooming of the lens can be realized, and the present application has the advantages of compact structure, large aperture, high imaging quality, and the like.

The following embodiments of the present application will also embody several specific examples of a zoom lens that satisfies the above-described condition with reference to the drawings.

Example one

Referring to fig. 3 to 8, fig. 3 is a schematic structural diagram of a zoom lens according to a first embodiment of the present disclosure in a wide angle state, fig. 4 is a graph illustrating curvature of field characteristics of the zoom lens shown in fig. 3, fig. 5 is a graph illustrating distortion characteristics of the zoom lens shown in fig. 3, fig. 6 is a schematic structural diagram of the zoom lens according to the first embodiment of the present disclosure in a telephoto state, fig. 7 is a graph illustrating curvature of field characteristics of the zoom lens shown in fig. 6, and fig. 8 is a graph illustrating distortion characteristics of the zoom lens shown in fig. 6.

As shown in fig. 3 and 5, the zoom lens according to the embodiment of the present application includes, from the object side to the image side, a cemented lens group (third lens group 5) formed by combining a first lens 1 (first lens group), a first focusing group 2, a stop 7, a second lens 3 (second lens group), a second focusing group 4, a third lens 51, and a fourth lens 52, a fifth lens 6 (fourth lens group), and an optical filter 8. The first lens 1, the fourth lens 52, and the fifth lens 6 each have a negative power, and the second lens 3 and the third lens 51 each have a positive power.

Wherein, the concave-convex condition of each lens at the optical axis is as follows: the object-side surface and the image-side surface of the first lens element 1 are concave and the image-side surface thereof is convex, the object-side surface and the image-side surface of the second lens element 3 are convex and the image-side surface thereof is concave, the object-side surface and the image-side surface of the third lens element 51 are convex, the object-side surface and the image-side surface of the fourth lens element 52 are concave, and the object-side surface and the image-side surface of the fifth lens element 6 are concave. The concave-convex conditions of the respective lenses at the circumference are substantially the same as those described above, except that the image-side surface of the fifth lens element 6 is convex, that is, the image-side surface of the fifth lens element 6 is concave at the optical axis and convex at the circumference.

Table 1 below shows the relevant parameters of each lens in the first embodiment, in which the unit of the curvature radius, the thickness and the focal length are mm. As can be seen from table 1, in the first embodiment, the second lens 3 and the fifth lens 6 are both aspheric lenses, and the remaining lenses may be spherical lenses. The surface type x of each aspherical lens can be calculated by (without limitation) the following formula:

wherein x is the rise of the distance from the aspheric surface vertex at the position with the height h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c =1/R (i.e., paraxial curvature c is the inverse of the radius of curvature in table 1 above); k is a conic coefficient; ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 below shows the coefficients k, a4, a6, A8, a10, a12, a14, a16, a18, and a20 of the object-side surface/image-side surface of each aspherical lens used in example one.

Table 1 table of basic parameters of each lens in zoom lens according to embodiment

Table 2 coefficients of aspherical lenses in example i

In particular practice, the focal length of the lenses can be changed by controlling the first and

second focus groups

2 and 4 so that the zoom lens can be switched between a telephoto state and a wide-angle state.

Table 3 table of basic parameters of zoom lens according to first embodiment

Table 3 above shows the basic parameter tables of the zoom lens system according to the first embodiment in the wide angle state and the telephoto state. Wherein EFL is the total effective focal length of the zoom lens; the FOV is the view field angle of the zoom lens; FNO is the F number of the zoom lens, namely the ratio of the focal length of the zoom lens to the diameter of an entrance pupil; LEF1 is the effective focal length of the first focusing group 2; LEF2 is the effective focal length of the second focus group 4. When the zoom lens switches between the wide-angle state and the telephoto state, the total optical length TTL does not change. The values of the conditional expressions of example one can be obtained from tables 1 and 3, and are specifically shown in table 4 below; among them, D12, D23 and D45 are preset values given according to the relevant parameters and distribution of each lens, and they can be adjusted properly in the actual design. As is clear from table 4, the values of the conditional expressions in the present example are all within the above-described setting ranges.

Table 4 table of values of conditional expressions of zoom lens according to embodiment one

Fig. 4 and 7 show field curvature characteristics in the wide angle state and the telephoto state, respectively, where a dotted line is a meridional field curve and a solid line is a sagittal field curve, and fig. 5 and 8 show distortion characteristics in the wide angle state and the telephoto state, respectively, indicating distortion magnitude values corresponding to different image heights. As can be seen from the figure, the zoom lens provided by the present embodiment has better imaging quality in both the wide angle state and the telephoto state; the zoom lens has small difference of imaging characteristics between the wide angle state and the telephoto state, and the stability of the lens in the focusing process is high.

Example two

Referring to fig. 9 to 14, fig. 9 is a schematic structural diagram of a zoom lens according to a second embodiment of the present disclosure in a wide angle state, fig. 10 is a graph illustrating curvature of field characteristics of the zoom lens shown in fig. 9, fig. 11 is a graph illustrating distortion characteristics of the zoom lens shown in fig. 9, fig. 12 is a schematic structural diagram of the zoom lens according to the second embodiment of the present disclosure in a telephoto state, fig. 13 is a graph illustrating curvature of field characteristics of the zoom lens shown in fig. 12, and fig. 14 is a graph illustrating distortion characteristics of the zoom lens shown in fig. 12.

As shown in fig. 9 and 12, the present example provides a second embodiment, which is the same as the first embodiment in terms of the number of lenses and the power, and a repetitive description will not be made here. What is different is that in the present embodiment, the image-side surface of the fourth lens element 52 is convex at the optical axis, and the object-side surface of the fifth lens element 6 is convex at the optical axis; the image-side surface of the fourth lens element 52 is convex at the circumference, the object-side surface of the fifth lens element 6 is convex at the circumference, and the image-side surface of the fifth lens element 6 is concave at the circumference.

Table 5 below shows the relevant parameters of each lens in example two, and the units of the radius of curvature, the thickness and the focal length are all mm. As can be seen from table 5, in the second embodiment, the second lens 3 and the fifth lens 6 are both aspheric lenses, and the remaining lenses may be spherical lenses. Table 6 below shows the coefficients k, a4, a6, A8, a10, a12, a14, a16, a18, and a20 of the object-side surface/image-side surface of each aspherical lens in example two.

TABLE 5 TABLE OF BASE PARAMETERS OF LENSES IN DIFFERENT LENSES

TABLE 6 coefficients of aspherical lenses of example two

second focus groups

Table 7 below shows a basic parameter table in the wide angle state and the telephoto state of the zoom lens system according to the second embodiment, and the definition of each parameter is described in a part of the embodiments. When the zoom lens switches between the wide-angle state and the telephoto state, the total optical length TTL does not change. The values of the conditional expressions of example two can be obtained from tables 5 and 7, and are specifically shown in table 8 below; among them, D12, D23 and D45 are preset values given according to the relevant parameters and distribution of each lens, and they can be adjusted properly in the actual design. As is clear from table 8, the values of the conditional expressions in the present example are all within the above-described setting ranges.

TABLE 7 TABLE OF BASE PARAMETERS OF DIFFERENT LENS FOR DIFFERENT LENS

Table 8 table of values of respective conditional expressions of the zoom lens system according to the second embodiment

Fig. 10 and 13 show field curvature characteristics in the wide angle state and the telephoto state, respectively, in which a broken line is a meridional field curve and a solid line is a sagittal field curve, and fig. 11 and 14 show distortion characteristics in the wide angle state and the telephoto state, respectively, indicating distortion magnitude values corresponding to different image heights. As can be seen from the figure, the zoom lens provided by the present embodiment has better imaging quality in both the wide angle state and the telephoto state; the zoom lens has small difference of imaging characteristics between the wide angle state and the telephoto state, and the stability of the lens in the focusing process is high.

EXAMPLE III

Referring to fig. 15 to 20, fig. 15 is a schematic structural diagram of a zoom lens according to a third embodiment of the present disclosure in a wide angle state, fig. 16 is a graph illustrating curvature of field characteristics of the zoom lens shown in fig. 15, fig. 17 is a graph illustrating distortion characteristics of the zoom lens shown in fig. 15, fig. 18 is a schematic structural diagram of a zoom lens according to a third embodiment of the present disclosure in a telephoto state, fig. 19 is a graph illustrating curvature of field characteristics of the zoom lens shown in fig. 18, and fig. 20 is a graph illustrating distortion characteristics of the zoom lens shown in fig. 18.

As shown in fig. 15 and 18, the present example provides a third embodiment, which is the same as the first embodiment in terms of the number of lenses and the power, and a repetitive description will not be made here. What is different is that in the present embodiment, the image-side surface of the third lens element 51 is concave at the optical axis, and the object-side surface of the fourth lens element 52 is convex at the optical axis; the image-side surface of the third lens element 51 is concave at the circumference, and the object-side surface of the fourth lens element 52 is convex at the circumference.

Table 9 below shows the relevant parameters of each lens in example three, and the units of the radius of curvature, the thickness and the focal length are all mm. As can be seen from table 9, the second lens 3 and the fifth lens 6 in the third embodiment both adopt aspheric lenses, and the other lenses can adopt spherical lenses; the filter 8 in the third embodiment is an infrared cut filter. Table 10 below gives the coefficients k, a4, a6, A8, a10, a12, a14, a16, a18, a20 of the object side/image side of each aspherical lens used in example three.

second focus groups

TABLE 9 basic parameter tables for respective lenses of zoom lens system according to third embodiment

TABLE 10 coefficients of aspherical lenses in example III

TABLE 11 basic parameter Table of zoom lens system according to the third embodiment

Table 11 above shows a basic parameter table of the zoom lens system according to the third embodiment in the wide angle state and the telephoto state, and the definition of each parameter is described in a part of the description of the third embodiment. When the zoom lens switches between the wide-angle state and the telephoto state, the total optical length TTL does not change. The values of the conditional expressions of example three can be obtained from tables 9 and 11, and are specifically shown in table 12 below, where D12, D23, and D45 are preset values according to the relevant parameters and distribution of the lenses, and they can be adjusted appropriately in the actual design. As is clear from table 12, the values of the conditional expressions of the present example are all within the above-described setting ranges.

Table 12 table of values of respective conditional expressions of the zoom lens system according to the third embodiment

Fig. 16 and 19 show field curvature characteristics in the wide angle state and the telephoto state, respectively, in which a broken line is a meridional field curve and a solid line is a sagittal field curve, and fig. 17 and 20 show distortion characteristics in the wide angle state and the telephoto state, respectively, indicating distortion magnitude values corresponding to different image heights. As can be seen from the figure, the zoom lens provided by the present embodiment has better imaging quality in both the wide angle state and the telephoto state; and the difference of imaging characteristics between the wide-angle state and the telephoto state is small, and the stability of the lens in the focusing process is high.

Example four

Referring to fig. 21 to 26, fig. 21 is a schematic structural diagram of a zoom lens according to a fourth embodiment of the present disclosure in a wide angle state, fig. 22 is a graph illustrating curvature of field characteristics of the zoom lens shown in fig. 21, fig. 23 is a graph illustrating distortion characteristics of the zoom lens shown in fig. 21, fig. 24 is a schematic structural diagram of a zoom lens according to a fourth embodiment of the zoom lens shown in the present disclosure in a telephoto state, fig. 25 is a graph illustrating curvature of field characteristics of the zoom lens shown in fig. 24, and fig. 26 is a graph illustrating distortion characteristics of the zoom lens shown in fig. 24.

As shown in fig. 21 and 24, the present example provides a fourth embodiment, which has the same number of lenses as the first embodiment, and will not be described repeatedly. Except that in the present embodiment, the fifth lens 6 has positive optical power; the object side surface of the second lens 3 is concave at the optical axis and at the circumference, and the image side surface of the second lens 3 is convex at the optical axis and at the circumference; the object-side surface of the fifth lens element 6 is convex at the optical axis.

Table 13 below shows the relevant parameters of each lens in example four, and the units of the radius of curvature, the thickness, and the focal length are all mm. As can be seen from table 13, in the fourth embodiment, each of the second lens 3 and the fifth lens 6 is an aspheric lens, and each of the other lenses may be a spherical lens. Table 14 below gives the coefficients k, a4, a6, A8, a10, a12, a14, a16, a18, a20 of the object side/image side of each aspherical lens used in example four.

second focus groups

Table 15 below shows a basic parameter table in the wide angle state and the telephoto state of the zoom lens according to the fourth embodiment, and the definition of each parameter is described in a part of the embodiments. When the zoom lens switches between the wide-angle state and the telephoto state, the total optical length TTL does not change. The values of the conditional expressions of example four can be obtained from tables 13 and 15, and are shown in table 16 below, wherein D12, D23 and D45 are preset values according to the relevant parameters and distribution of the lenses, and they can be adjusted appropriately in the actual design. As is clear from table 16, the values of the conditional expressions in the present example are all within the above-described setting ranges.

TABLE 13 basic parameter tables for respective lenses of zoom lens system according to fourth embodiment

TABLE 14 coefficients of aspherical lenses of example four

Fig. 22 and 25 show field curvature characteristics in the wide angle state and the telephoto state, respectively, in which a broken line is a meridional field curve and a solid line is a sagittal field curve, and fig. 23 and 26 show distortion characteristics in the wide angle state and the telephoto state, respectively, indicating distortion magnitude values corresponding to different image heights. As can be seen from the figure, the zoom lens provided by the present embodiment has better imaging quality in both the wide angle state and the telephoto state; and the difference of imaging characteristics between the wide-angle state and the telephoto state is small, and the stability of the lens in the focusing process is high.

Table 15 table of basic parameters of zoom lens system according to fourth embodiment

Table 16 table of values of conditional expressions of zoom lens system according to embodiment four

EXAMPLE five

Referring to fig. 27 to fig. 32, fig. 27 is a schematic structural diagram of a zoom lens according to a fifth implementation manner of the present disclosure in a wide angle state, fig. 28 is a graph of curvature of field characteristics of the zoom lens shown in fig. 27, fig. 29 is a graph of distortion characteristics of the zoom lens shown in fig. 27, fig. 30 is a schematic structural diagram of the zoom lens according to the fifth implementation manner of the present disclosure in a telephoto state, fig. 31 is a graph of curvature of field characteristics of the zoom lens shown in fig. 30, and fig. 32 is a graph of distortion characteristics of the zoom lens shown in fig. 30.

As shown in fig. 27 and 30, the present example provides a fifth embodiment, which is the same as the first embodiment in terms of the number of lenses and the power, and a repetitive description will not be made here. What is different is that in the present embodiment, the image-side surface of the fourth lens element 52 is convex at the optical axis, and the object-side surface of the fifth lens element 6 is convex at the optical axis; the image-side surface of the fourth lens element 52 is convex at the circumference; the object-side surface of the fifth lens element 6 is convex at the circumference, and the image-side surface of the fifth lens element 6 is concave at the circumference.

Table 17 below shows the relevant parameters for each lens in example five, with the radius of curvature, thickness and focal length all in mm. As can be seen from table 17, in the fifth embodiment, the second lens 3 and the fifth lens 6 both adopt aspheric lenses, and the remaining lenses can adopt spherical lenses; the filter 8 in the fifth embodiment is an infrared cut filter. Table 18 below gives the coefficients k, a4, a6, A8, a10, a12, a14, a16, a18, a20 of the object side/image side of each aspherical lens used in example five.

second focus groups

Table 19 below shows a basic parameter table in the wide angle state and in the telephoto state of the zoom lens system according to fifth embodiment, and the definition of each parameter is described in a part of the embodiments. When the zoom lens switches between the wide-angle state and the telephoto state, the total optical length TTL does not change. The values of the conditional expressions of example five can be obtained from tables 17 and 19, and are specifically shown in table 20 below, where D12, D23, and D45 are preset values according to the relevant parameters and distribution of the lenses, and they can be adjusted appropriately in the actual design. As can be seen from table 20, the values of the conditional expressions of the present example are all within the above-described setting ranges.

TABLE 17 TABLE OF BASE PARAMETERS OF LENSES IN VARIABLE LENS

TABLE 18 coefficients of aspherical lenses of example V

Table 19 basic parameter table of zoom lens system according to fifth embodiment

Table 20 table of values of respective conditional expressions of zoom lens system according to fifth embodiment

Fig. 28 and 31 show field curvature characteristics in the wide angle state and the telephoto state, respectively, in which the broken line is a meridional field curve and the solid line is a sagittal field curve, and fig. 29 and 32 show distortion characteristics in the wide angle state and the telephoto state, respectively, indicating distortion magnitude values corresponding to different image heights. As can be seen from the figure, the zoom lens provided by the present embodiment has better imaging quality in both the wide angle state and the telephoto state; and the difference of imaging characteristics between the wide-angle state and the telephoto state is small, and the stability of the lens in the focusing process is high.

EXAMPLE six

Referring to fig. 33-38, fig. 33 is a schematic structural diagram of a zoom lens according to a sixth implementation manner of the present embodiment in a wide angle state, fig. 34 is a graph of curvature of field characteristic of the zoom lens shown in fig. 33, fig. 35 is a graph of distortion characteristic of the zoom lens shown in fig. 33, fig. 36 is a schematic structural diagram of the zoom lens according to the sixth implementation manner of the zoom lens shown in the present embodiment in a telephoto state, fig. 37 is a graph of curvature of field characteristic of the zoom lens shown in fig. 36, and fig. 38 is a graph of distortion characteristic of the zoom lens shown in fig. 36.

As shown in fig. 33 and fig. 36, the present example provides a sixth implementation mode, which is the same as the first example in terms of the number of lenses and the power, and a repetitive description will not be made here. What is different is that in the present embodiment, the image-side surface of the third lens element 51 is concave at the optical axis, and the object-side surface of the fourth lens element 52 is convex at the optical axis; the third lens element 51 has a concave image-side surface at the circumference and the fourth lens element 52 has a convex object-side surface at the circumference.

Table 21 below shows the relevant parameters of each lens in example six, and the units of the radius of curvature, the thickness, and the focal length are all mm. As can be seen from table 17, the second lens 3 and the fifth lens 6 in the sixth embodiment both use aspheric lenses, and the remaining lenses can use spherical lenses; the filter 8 in the sixth embodiment is an infrared cut filter. Table 22 below shows the coefficients k, a4, a6, A8, a10, a12, a14, a16, a18, and a20 of the object-side surface/image-side surface of each aspherical lens in example six.

second focus groups

Table 23 below shows a basic parameter table in the wide angle state and the telephoto state of the zoom lens system according to the sixth embodiment, and the definition of each parameter is described in a part of the embodiments. When the zoom lens switches between the wide-angle state and the telephoto state, the total optical length TTL does not change. The values of the conditional expressions of example six can be obtained from tables 21 and 23, and are shown in table 24 below, wherein D12, D23, and D45 are preset values according to the relevant parameters and distribution of the lenses, and they can be adjusted appropriately in the actual design. As can be seen from table 24, the values of the conditional expressions of the present example are all within the above-described setting ranges.

TABLE 21 basic parameter tables for respective lenses of zoom lens according to sixth embodiment

TABLE 22 coefficients of aspherical lenses in example six

Fig. 34 and 37 show field curvature characteristics in the wide angle state and the telephoto state, respectively, in which a broken line is a meridional field curve and a solid line is a sagittal field curve, and fig. 35 and 38 show distortion characteristics in the wide angle state and the telephoto state, respectively, indicating distortion magnitude values corresponding to different image heights. As can be seen from the figure, the zoom lens provided by the present embodiment has better imaging quality in both the wide angle state and the telephoto state; and the difference of imaging characteristics between the wide-angle state and the telephoto state is small, and the stability of the lens in the focusing process is high.

TABLE 23 basic parameter Table of zoom lens system according to sixth embodiment

Table 24 table of values of conditional expressions of zoom lens system according to sixth embodiment

The foregoing is only a preferred embodiment of the present application and it should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. The zoom lens is characterized by comprising a first lens group, a first focusing group, a second lens group, a second focusing group, a third lens group and a fourth lens group in sequence from an object side to an image side; the first lens group, the second lens group, the third lens group, and the fourth lens group each include at least one lens; the first lens group has negative optical power, and the first focusing group and the second focusing group each comprise at least one focusing element; the effective focal length FT of the zoom lens in a long-focus state and the effective focal length FW of the zoom lens in a wide-angle state have the following relationship: FT/FW is not less than 1.5.

2. The zoom lens according to claim 1, wherein at least one lens of the first lens group, the second lens group, the third lens group, and the fourth lens group is an aspherical lens.

3. The zoom lens according to claim 1, wherein the following relationship exists between an effective focal length F1 of the first lens group and an effective focal length FT of the zoom lens in a telephoto state: -5.5< F1/FT < -1.5.

4. The zoom lens according to claim 1, wherein a radius of curvature R11 of an object side surface of the first lens group and a radius of curvature R12 of an image side surface of the first lens group have a relationship therebetween: 0.6 < R11/R12 < 0.9.

5. The zoom lens of claim 1, wherein an effective focal length LEFW1 of the first focus group in the wide state and an effective focal length LEFT1 of the first focus group in the telephoto state have the following relationship: 1 < | LEFW1/LEFT1| < 4.5.

6. The zoom lens according to claim 1, wherein a distance D12 between an image-side surface of the first lens group and an object-side surface of the second lens group in an optical axis direction, a distance D23 between the image-side surface of the second lens group and an object-side surface of the third lens group in the optical axis direction, and a total optical length TTL of the zoom lens are in the following relationship: (D12 + D23)/TTL is more than or equal to 0.3.

7. The zoom lens of claim 1, wherein an effective focal length LEFW2 of the second focus group in the wide state and an effective focal length LEFT2 of the second focus group in the telephoto state have the following relationship: 1 < | LEFW2/LEFT2| < 2.

8. The zoom lens according to claim 1, wherein the third lens group comprises a third lens and a fourth lens, which are cemented together; the effective focal length F4 of the fourth lens and the effective focal length F3 of the third lens have the following relationship: -2.5 < F4/F3 < -1.

9. The zoom lens according to claim 1, wherein a distance D45 between the third lens group and the fourth lens group in the optical axis direction and a total optical length TTL of the zoom lens have the following relationship: D45/TTL is less than or equal to 0.1.

10. The zoom lens according to claim 1, wherein the following relationship exists between total optical length TTL of the zoom lens and effective focal length FT of the zoom lens in the telephoto state: TTL/FT < 1.8.

11. The zoom lens of any one of claims 1 to 10, further comprising an optical stop disposed between the first focusing group and the second lens group.

12. The zoom lens according to any one of claims 1 to 10, further comprising a filter disposed on a side of the fourth lens group facing away from the third lens group.

13. The zoom lens according to claim 12, wherein the filter is an infrared cut filter.

14. A terminal device, comprising a body and a camera module, wherein the camera module comprises a lens, and the lens is the zoom lens according to any one of claims 1-13.