CN211905844U

CN211905844U - Zoom lens group

Info

Publication number: CN211905844U
Application number: CN202020601817.5U
Authority: CN
Inventors: 张伊; 戴付建; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2020-04-21
Filing date: 2020-04-21
Publication date: 2020-11-10
Anticipated expiration: 2030-04-21

Abstract

The application discloses a zoom lens group, it includes from the object side to the image side along the optical axis in order: the first lens group with negative focal power comprises a first lens and a second lens, wherein the first lens has positive focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; a second lens group having positive optical power, including a third lens and a fourth lens; a third lens group having power, including a fifth lens and a sixth lens, wherein the fifth lens and the sixth lens form a cemented lens; and a fourth lens group having power, including a seventh lens. The distance between the first lens group and the second lens group on the optical axis, the distance between the second lens group and the third lens group on the optical axis, and the distance between the third lens group and the fourth lens group on the optical axis are changed to realize the switching of the zoom lens group from the telephoto state to the wide-angle state.

Description

Zoom lens group

Technical Field

The present application relates to the field of optical elements, in particular to a variable focus lens package.

Background

With the development of the camera technology and the rise of the internet industry, the requirements of users on the photographing level and the camera quality of mobile devices such as smart phones and video cameras are higher and higher. At present, lens manufacturers in the field generally adopt a method for optimizing the imaging quality of lenses by combining and matching ultra-clear main cameras, ultra-large wide angles and telephoto lenses. However, in the current market, the lens matched with the combination needs to be switched to different lenses to complete zooming when shooting different scenes. For example, most of the existing rear cameras are zooming in a "baton" mode, that is, zooming in a non-true optical sense is realized by switching between wide-angle main shooting and long focusing. In addition, installing multiple lenses in a mobile device not only greatly occupies the internal space of the mobile device, but also causes problems of high cost, large size, and large weight increase.

How to realize the 'continuous' zooming in the real optical sense and effectively ensure that the zooming lens group has the characteristics of low cost, small size, light weight, smooth and smooth transition of images in the optical zooming process and the like is one of the key problems to be solved by many optical lens designers.

SUMMERY OF THE UTILITY MODEL

The present application provides, in order from an object side to an image side along an optical axis, a zoom lens group comprising: the first lens group with negative focal power comprises a first lens and a second lens, wherein the first lens has positive focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; a second lens group having positive optical power, including a third lens and a fourth lens; a third lens group having power, including a fifth lens and a sixth lens, wherein the fifth lens and the sixth lens form a cemented lens; and a fourth lens group having power, including a seventh lens. Switching of the zoom lens group from the telephoto state to the wide-angle state can be achieved by changing a spacing distance of the first lens group and the second lens group on the optical axis, a spacing distance of the second lens group and the third lens group on the optical axis, and a spacing distance of the third lens group and the fourth lens group on the optical axis.

In one embodiment, the object-side surface of the first lens element to the image-side surface of the seventh lens element has at least one aspherical mirror surface.

In one embodiment, the total effective focal length FT when the zoom lens group is in the telephoto state and the total effective focal length FW when the zoom lens group is in the wide angle state may satisfy: 1.9 < FT/FW < 2.9.

In one embodiment, the effective focal length F1 of the first lens group and the effective focal length F2 of the second lens group may satisfy: -2.9 < F1/F2 < -1.6.

In one embodiment, the total effective focal length FT of the zoom lens group in the telephoto state may satisfy: FT is more than 29mm and less than 36 mm.

In one embodiment, a radius of curvature R1 of an object-side surface of the first lens, a radius of curvature R2 of an image-side surface of the first lens, and a total effective focal length FW of the zoom lens group in a wide-angle state may satisfy: 1.0 < (R1+ R2)/FW < 1.5.

In one embodiment, the effective focal length f11 of the first lens, the effective focal length f12 of the second lens, and the effective focal length f31 of the fifth lens may satisfy: 0.8 < (f11+ f12)/f31 < 1.3.

In one embodiment, the effective focal length f21 of the third lens and the radius of curvature R5 of the object side of the third lens may satisfy: f21/R5 is more than 0.8 and less than 1.3.

In one embodiment, the central thickness CT1 of the first lens on the optical axis and the central thickness CT7 of the seventh lens on the optical axis may satisfy: 1.0 < CT1/CT7 < 2.8.

In one embodiment, the radius of curvature R13 of the object-side surface of the seventh lens and the radius of curvature R14 of the image-side surface of the seventh lens may satisfy: 0.5 < R13/R14 < 1.0.

In one embodiment, a maximum field angle FOVW of the zoom lens group in a wide angle state may satisfy: 20 DEG < FOVW < 26 deg.

In one embodiment, at least one of the third lens element and the fourth lens element is a plastic lens element, and at least one of an object-side surface of the third lens element, an image-side surface of the third lens element, an object-side surface of the fourth lens element, and an image-side surface of the fourth lens element is an aspheric surface.

In one embodiment, the lenses in at least one of the first lens group and the third lens group are glass lenses.

The zoom lens group with continuous zooming, miniaturization, high integration and good imaging quality is provided by reasonably distributing focal power and optimizing optical parameters.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

fig. 1 is a schematic structural view showing a zoom lens group according to embodiment 1 of the present application in a telephoto state;

fig. 2 is a schematic configuration diagram showing an intermediate state of a zoom lens group according to embodiment 1 of the present application in a process of switching from a telephoto state to a wide-angle state;

fig. 3 is a schematic structural view showing a zoom lens group according to embodiment 1 of the present application in a wide-angle state;

fig. 4A to 4D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, in a telephoto state of the zoom lens group of embodiment 1;

fig. 5A to 5D respectively show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve in an intermediate state in the process of switching the zoom lens group of embodiment 1 from the telephoto state to the wide-angle state;

fig. 6A to 6D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, in a wide-angle state of the zoom lens group of embodiment 1;

fig. 7 is a schematic structural view showing a zoom lens group according to embodiment 2 of the present application in a telephoto state;

fig. 8 is a schematic structural view showing an intermediate state of a zoom lens group according to embodiment 2 of the present application in switching from a telephoto state to a wide-angle state;

fig. 9 is a schematic structural view showing a zoom lens group according to embodiment 2 of the present application in a wide angle state;

fig. 10A to 10D respectively show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve in a telephoto state of the zoom lens group of embodiment 2;

fig. 11A to 11D respectively show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve in an intermediate state in the process of switching the zoom lens group of embodiment 2 from the telephoto state to the wide-angle state;

fig. 12A to 12D respectively show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve in a wide-angle state of the zoom lens group of embodiment 2;

fig. 13 is a schematic structural view showing a zoom lens group according to embodiment 3 of the present application in a telephoto state;

fig. 14 is a schematic structural view showing an intermediate state of a zoom lens group according to embodiment 3 of the present application in switching from a telephoto state to a wide-angle state;

fig. 15 is a schematic structural view showing a zoom lens group according to embodiment 3 of the present application in a wide angle state;

fig. 16A to 16D respectively show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve in a telephoto state of the zoom lens group of embodiment 3;

fig. 17A to 17D respectively show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve in an intermediate state in the process of switching the zoom lens group of embodiment 3 from the telephoto state to the wide-angle state; and

fig. 18A to 18D show an on-axis chromatic aberration curve, an astigmatism curve, a distortion curve, and a chromatic aberration of magnification curve, respectively, when the zoom lens group of embodiment 3 is in a wide-angle state.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Accordingly, the first lens discussed below may also be referred to as the second lens or the third lens, and the first lens group may also be referred to as the second lens group or the third lens group, without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

The features, principles, and other aspects of the present application are described in detail below.

A zoom lens group according to an exemplary embodiment of the present application may include four lens groups having power, respectively, a first lens group, a second lens group, a third lens group, and a fourth lens group. Switching of the zoom lens group from the telephoto state to the wide-angle state can be achieved by changing a spacing distance of the first lens group and the second lens group on the optical axis, a spacing distance of the second lens group and the third lens group on the optical axis, and a spacing distance of the third lens group and the fourth lens group on the optical axis.

According to an exemplary embodiment of the present application, the first lens group may have a negative power, and may include a first lens and a second lens, wherein the first lens may have a positive power, and an object-side surface thereof may be a convex surface and an image-side surface thereof may be a concave surface; the second lens group may have positive optical power, and may include a third lens and a fourth lens; the third lens group may have positive power or negative power, and may include a fifth lens and a sixth lens, wherein the fifth lens and the sixth lens may be cemented to form a cemented lens; the fourth lens group may have positive power or negative power, and may include a seventh lens. The seven lenses are arranged along the optical axis in sequence from the object side to the image side.

The distances among the lens groups are controlled by reasonably distributing the focal power among the lens groups and the focal power of each lens in each lens group, so that when the whole system is in work and is switched from a long-focus state to a wide-angle state, the four lens groups can realize a continuous zooming function by changing the spacing distance among the adjacent lens groups. The specific zooming process can be realized by the following steps: by reasonably distributing the system focal power, when the system is in a wide-angle state, the distance between the zooming groups formed by the first lens group and the second lens group is the largest, and the distance between the compensating groups formed by the second lens group and the third lens group is the smallest, so that the system achieves the purposes of minimum focal length and maximum field angle. When the system is switched from a wide-angle state to a telephoto state, the zoom group pitch formed by the first lens group and the second lens group is shortened, and the compensation group pitch formed by the second lens group and the third lens group is lengthened. The ratio of the total effective focal length of the zoom lens group in the telephoto state to the total effective focal length of the zoom lens group in the wide-angle state can be continuously changed to complete the continuous zooming process of the zoom lens group.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: 1.9 < FT/FW < 2.9, wherein FT is a total effective focal length of the zoom lens group in the telephoto state, and FW is a total effective focal length of the zoom lens group in the wide-angle state. More specifically, FT and FW may further satisfy: 1.9 < FT/FW < 2.8. The zoom lens system meets the condition that FT/FW is more than 1.9 and less than 2.9, and can effectively control the continuous zooming range under the condition of controlling the size of the image plane of the zoom lens group in the telephoto state and the wide-angle state, so that the lens system has a continuous zooming function in a certain range.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: -2.9 < F1/F2 < -1.6, wherein F1 is the effective focal length of the first lens group and F2 is the effective focal length of the second lens group. Satisfy-2.9 < F1/F2 < -1.6, can rationally distribute the focal power of whole system, guarantee that the system has the function of continuous zoom in a certain extent.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: 29mm < FT < 36mm, where FT is the total effective focal length of the variable focus lens package in the tele state. The requirement that FT is more than 29mm and less than 36mm is met, the system can have a larger effective focal length in a long-focus state, and therefore the whole system can be guaranteed to have a continuous zooming function in a larger range.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: 1.0 < (R1+ R2)/FW < 1.5, wherein R1 is a radius of curvature of an object-side surface of the first lens, R2 is a radius of curvature of an image-side surface of the first lens, and FW is a total effective focal length of the zoom lens group in a wide-angle state. More specifically, R1, R2, and FW may further satisfy: 1.1 < (R1+ R2)/FW < 1.4. Satisfying 1.0 < (R1+ R2)/FW < 1.5, the focal power of each lens in the first lens group can be reasonably distributed, so that the total effective focal length in a wide-angle state is in a small range, and the system can be effectively ensured to have a large continuous zooming range.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: 0.8 < (f11+ f12)/f31 < 1.3, wherein f11 is the effective focal length of the first lens, f12 is the effective focal length of the second lens, and f31 is the effective focal length of the fifth lens. More specifically, f11, f12, and f31 may further satisfy: 0.9 < (f11+ f12)/f31 < 1.3. Satisfying 0.8 < (f11+ f12)/f31 < 1.3, the optical powers of the first lens, the second lens and the third lens can be effectively distributed, and the system can have higher image quality under the condition of ensuring key parameters of the system.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: 0.8 < f21/R5 < 1.3, wherein f21 is the effective focal length of the third lens and R5 is the radius of curvature of the object side of the third lens. Satisfying 0.8 < f21/R5 < 1.3 makes it possible for the third lens element, which has the main power of the second lens group, to have reasonable powers on both the object-side and image-side surfaces, so that the third lens element can have its sensitivity reduced as much as possible while satisfying optical performance.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: 1.0 < CT1/CT7 < 2.8, wherein CT1 is the central thickness of the first lens on the optical axis, and CT7 is the central thickness of the seventh lens on the optical axis. The requirements that 1.0 < CT1/CT7 < 2.8 are met, the distortion contribution amounts of the first lens and the seventh lens can be controlled within a reasonable range, so that the distortion amounts of all fields of the zoom lens group are within a reasonable required range, and the requirements of later software debugging are favorably met.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: 0.5 < R13/R14 < 1.0, wherein R13 is a radius of curvature of an object-side surface of the seventh lens, and R14 is a radius of curvature of an image-side surface of the seventh lens. More specifically, R13 and R14 may further satisfy: 0.7 < R13/R14 < 1.0. The third lens can effectively control the coma contribution rate of the seventh lens to the whole system within a reasonable range, further balance the coma generated by the front end lens and obtain good imaging quality.

In an exemplary embodiment, a zoom lens group according to the present application may satisfy: 20 DEG < FOVW < 26 DEG, where FOVW is the maximum angle of view of the zoom lens group in the wide-angle state. The FOVW is more than 20 degrees and less than 26 degrees, the effective focal length of the zoom lens group is favorably maximized, and the whole system is favorably ensured to have a larger continuous zoom range.

In an exemplary embodiment, at least one of the third lens and the fourth lens is a plastic lens, and at least one of an object-side surface of the third lens, an image-side surface of the third lens, an object-side surface of the fourth lens, and an image-side surface of the fourth lens is an aspheric mirror surface. At least one lens in the second lens group is made of plastic materials, so that the weight of the whole system is favorably ensured not to be too heavy. At least one lens in the second lens group has at least one aspheric surface mirror surface, which is beneficial to ensuring that the system has more optimized freedom degree, thereby being beneficial to ensuring that the system has higher resolving power.

In an exemplary embodiment, lenses in at least one of the first lens group and the third lens group are glass lenses. Because the refractive index distribution range of the glass is wider, the expansion coefficient is smaller, and the lens in at least one lens group in the first lens group and the third lens group of the whole system is made of glass, the system is favorably ensured to have better imaging quality, and the temperature drift effect of the whole system is favorably controlled.

In an exemplary embodiment, a zoom lens group according to the present application further includes a stop disposed between the first lens group and the second lens group. Optionally, the above zoom lens group may further include a filter for correcting color deviation and/or a protective glass for protecting a photosensitive element located on an image plane.

The present application provides a zoom lens group having characteristics of continuous zooming, high integration, miniaturization, high imaging quality, and the like. The variable focus lens package according to the above embodiments of the present application may employ a plurality of lenses, for example, seven lenses as described above. By reasonably distributing the focal power and the surface type of each lens, the central thickness of each lens, the axial distance between each lens and the like, incident light can be effectively converged, the optical total length of the imaging lens is reduced, the processability of the imaging lens is improved, and the zoom lens group is more favorable for production and processing.

In the embodiment of the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one of the object-side surface of the first lens to the image-side surface of the seventh lens is an aspherical mirror surface. The aspheric lens is characterized in that: the curvature varies continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics, and has advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, at least one of an object-side surface and an image-side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens is an aspheric mirror surface. Optionally, each of the first, second, third, fourth, fifth, sixth, and seventh lenses has an object-side surface and an image-side surface that are aspheric mirror surfaces.

However, it will be appreciated by those skilled in the art that the number of lenses constituting the variable focus lens package may be varied without departing from the technical solutions claimed herein to achieve the respective results and advantages described in the present specification. For example, although seven lenses are exemplified in the embodiment, the zoom lens group is not limited to include seven lenses. The variable focus lens package may also comprise other numbers of lenses, if desired.

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

Example 1

A zoom lens group according to embodiment 1 of the present application is described below with reference to fig. 1 to 6D. Fig. 1 shows a schematic configuration diagram of a zoom lens group according to embodiment 1 of the present application in a telephoto state. Fig. 2 is a schematic configuration diagram showing an intermediate state of a zoom lens group according to embodiment 1 of the present application in switching from a telephoto state to a wide-angle state. Fig. 3 shows a schematic configuration diagram of a zoom lens group according to embodiment 1 of the present application in a wide angle state.

As shown in fig. 1-3, the zoom lens assembly, in order from an object side to an image side, comprises: a first lens group G1 (first lens E1 and second lens E2), a second lens group G2 (third lens E3 and fourth lens E4), a third lens group G3 (fifth lens E5 and sixth lens E6), a fourth lens group G4 (seventh lens E7), a filter E8, and an image plane S17.

The object-side surface S1 of the first lens element E1 is convex, and the image-side surface S2 is concave. The object-side surface S3 of the second lens element E2 is concave, and the image-side surface S4 is concave. The object-side surface S5 of the third lens element E3 is convex, and the image-side surface S6 is convex. The object-side surface S7 of the fourth lens element E4 is convex, and the image-side surface S8 is concave. The object-side surface S9 of the fifth lens element E5 is convex, and the image-side surface S10 is convex. The object-side surface S11 of the sixth lens element E6 is concave, and the image-side surface S12 is convex. The object-side surface S13 of the seventh lens element E7 is concave, and the image-side surface S14 is convex. Filter E8 has an object side S15 and an image side S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

Table 1 shows a basic parameter table of the zoom lens group of embodiment 1, in which the unit of the radius of curvature and the thickness/distance are both millimeters (mm).

Flour mark	Surface type	Radius of curvature	Thickness/distance	Refractive index	Abbe number	Material of	Coefficient of cone
								OBJ	Spherical surface	All-round	All-round
S1	Spherical surface	8.5227	3.2648	1.91	31.4	Glass
								S2	Spherical surface	8.5572	0.8066
S3	Spherical surface	-18.1410	0.4200	1.65	58.4	Glass
								S4	Spherical surface	14.4384	D4
S5(STO)	Spherical surface	6.9142	1.0224	1.74	52.7	Glass
								S6	Spherical surface	-29.1766	0.0300
S7	Aspherical surface	22.9486	0.5500	1.67	20.4	Plastic cement	0.0000
								S8	Aspherical surface	7.0216	D8	0.0000
S9	Spherical surface	27.0482	0.6036	1.50	81.6	Glass
								S10	Spherical surface	-57.3354	0.0000
S11	Spherical surface	-57.3354	1.3721	1.93	20.9	Glass
								S12	Spherical surface	-41.9373	D12
S13	Spherical surface	-6.1084	1.2323	1.93	20.9	Glass
								S14	Spherical surface	-6.6345	14.5000
S15	Spherical surface	All-round	0.2100	1.52	64.2
								S16	Spherical surface	All-round	0.2900
S17	Spherical surface	All-round

TABLE 1

In the present example, switching of the zoom lens group from the telephoto state to the wide-angle state or from the wide-angle state to the telephoto state is achieved by changing a spacing distance D4 on the optical axis of the first lens group and the second lens group (i.e., a spacing distance on the optical axis of an image side surface of the second lens E2 to an object side surface of the third lens E3), a spacing distance D8 on the optical axis of the second lens group and the third lens group (i.e., a spacing distance on the optical axis of an image side surface of the fourth lens E4 to an object side surface of the fifth lens E5), and a spacing distance D12 on the optical axis of the third lens group and the fourth lens group (i.e., a spacing distance on the optical axis of an image side surface of the sixth lens E6 to an object side surface of the seventh lens E7). The total effective focal length f, the aperture value Fno, the maximum field angle FOV, the total length TTL of the zoom lens group (i.e., the distance on the optical axis from the object-side surface S1 of the first lens E1 to the imaging surface S17 of the zoom lens group), and half ImgH of the diagonal length of the effective pixel area on the imaging surface S17 of the zoom lens group vary as the zoom lens group switches from the telephoto state to the wide-angle state or from the wide-angle state to the telephoto state.

Table 2 shows various parameter tables in different states of the zoom lens group of example 1, in which the units of f, TTL, ImgH, D4, D8, and D12 are all millimeters (mm), and the unit of FOV is degrees (°).

Each parameter	State of long focus	Intermediate state	Wide angle state
				f	29.94	21.96	15.18
Fno	4.39	3.76	3.12
				FOV	10.4	14.2	20.9
TTL	32.80	32.80	32.80
				ImgH	2.72	2.72	2.72
D4	0.03	3.10	7.48
				D8	2.14	2.81	0.48
D12	6.33	2.59	0.54

TABLE 2

In embodiment 1, the object-side surface S7 and the image-side surface S8 of the fourth lens element E4 are both aspheric, and the profile x of each aspheric lens can be defined by, but is not limited to, the following aspheric formula:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is a conic coefficient; ai is the correction coefficient of the i-th order of the aspherical surface. Table 3 below shows the high-order term coefficients A that can be used for the aspherical mirror surfaces S7 and S8 in example 1₄、A₆、A₈、A₁₀And A₁₂。

Flour mark	A4	A6	A8	A10	A12
						S7	5.5482E-04	-6.7063E-05	1.9924E-06	-2.8679E-08	2.1129E-10
S8	1.4492E-03	-5.2293E-05	3.6304E-06	-1.0936E-07	1.7587E-09

TABLE 3

Fig. 4A, 5A, and 6A show axial chromatic aberration curves in a telephoto state, an intermediate state, and a wide-angle state, respectively, of the zoom lens group of example 1, which represent convergent focus deviations of light rays of different wavelengths after passing through the lens. Fig. 4B, 5B, and 6B show astigmatism curves representing meridional field curvature and sagittal field curvature in the telephoto state, the intermediate state, and the wide angle state, respectively, of the zoom lens group of example 1. Fig. 4C, 5C, and 6C show distortion curves of the zoom lens group of example 1 in the telephoto state, the intermediate state, and the wide-angle state, respectively, which represent values of distortion magnitudes corresponding to different image heights. Fig. 4D, 5D, and 6D show chromatic aberration of magnification curves representing deviations of different image heights on an image forming surface of light rays after passing through the lens in the telephoto state, the intermediate state, and the wide-angle state, respectively, of the zoom lens group of example 1. As can be seen from fig. 4A to 6D, the zoom lens group according to embodiment 1 can achieve good imaging quality in each state.

Example 2

A zoom lens group according to embodiment 2 of the present application is described below with reference to fig. 7 to 12D. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 7 is a schematic structural view showing a zoom lens group according to embodiment 2 of the present application in a telephoto state. Fig. 8 is a schematic structural diagram showing an intermediate state of a zoom lens group according to embodiment 2 of the present application in switching from a telephoto state to a wide-angle state. Fig. 9 shows a schematic configuration diagram of a zoom lens group according to embodiment 2 of the present application in a wide angle state.

As shown in fig. 7-9, the zoom lens assembly, in order from an object side to an image side, comprises: a first lens group G1 (first lens E1 and second lens E2), a second lens group G2 (third lens E3 and fourth lens E4), a third lens group G3 (fifth lens E5 and sixth lens E6), a fourth lens group G4 (seventh lens E7), a filter E8, and an image plane S17.

The object-side surface S1 of the first lens element E1 is convex, and the image-side surface S2 is concave. The object-side surface S3 of the second lens element E2 is concave, and the image-side surface S4 is concave. The object-side surface S5 of the third lens element E3 is convex, and the image-side surface S6 is convex. The object-side surface S7 of the fourth lens element E4 is concave, and the image-side surface S8 is concave. The object-side surface S9 of the fifth lens element E5 is convex, and the image-side surface S10 is concave. The object-side surface S11 of the sixth lens element E6 is convex, and the image-side surface S12 is concave. The object-side surface S13 of the seventh lens element E7 is concave, and the image-side surface S14 is convex. Filter E8 has an object side S15 and an image side S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

Table 4 shows a basic parameter table of the variable focus lens package of embodiment 2, in which the unit of the radius of curvature and the thickness/distance are both millimeters (mm).

TABLE 4

In the present example, switching of the zoom lens group from the telephoto state to the wide-angle state or from the wide-angle state to the telephoto state is achieved by changing a spacing distance D4 of the first lens group and the second lens group on the optical axis, a spacing distance D8 of the second lens group and the third lens group on the optical axis, and a spacing distance D12 of the third lens group and the fourth lens group on the optical axis. The total effective focal length f, the aperture value Fno, the maximum field angle FOV, the total length TTL of the zoom lens group, and half ImgH of the diagonal length of the effective pixel area on the imaging surface S17 of the zoom lens group vary as the zoom lens group is switched from the telephoto state to the wide-angle state or from the wide-angle state to the telephoto state.

Table 5 shows parameter tables of example 2 in different states of the zoom lens group, where the units of f, TTL, ImgH, D4, D8, and D12 are all millimeters (mm) and the unit of FOV is degrees (°).

Each parameter	State of long focus	Intermediate state	Wide angle state
				f	30.06	19.97	15.11
Fno	4.29	3.36	3.10
				FOV	10.4	15.6	21.1
TTL	35.00	30.08	34.48
				ImgH	2.72	2.72	2.72
D4	0.03	2.99	7.27
				D8	6.38	0.09	2.59
D12	4.63	3.05	0.66

TABLE 5

Table 6 shows high-order term coefficients that can be used for each aspherical mirror surface in example 2, wherein each aspherical mirror surface type can be defined by formula (1) given in example 1 above.

Flour mark	A4	A6	A8	A10	A12
						S7	3.6903E-04	-3.9860E-05	9.6922E-07	-1.1518E-08	7.1653E-11
S8	9.7424E-04	-3.0938E-05	1.5355E-06	-4.0302E-08	4.8859E-10

TABLE 6

Fig. 10A, 11A, and 12A show axial chromatic aberration curves in a telephoto state, an intermediate state, and a wide-angle state, respectively, of the zoom lens group of example 2, which indicate convergent focus deviations of light rays of different wavelengths after passing through the lens. Fig. 10B, 11B, and 12B show astigmatism curves representing meridional field curvature and sagittal field curvature in the telephoto state, the intermediate state, and the wide angle state, respectively, of the zoom lens group of example 2. Fig. 10C, 11C, and 12C show distortion curves of the zoom lens group of example 2 in the telephoto state, the intermediate state, and the wide-angle state, respectively, which represent values of distortion magnitudes corresponding to different image heights. Fig. 10D, 11D, and 12D show chromatic aberration of magnification curves representing deviations of different image heights on an image forming surface of light rays after passing through the lens in the telephoto state, the intermediate state, and the wide-angle state, respectively, of the zoom lens group of example 2. As can be seen from fig. 10A to 12D, the zoom lens group according to embodiment 2 can achieve good imaging quality in each state.

Example 3

A zoom lens group according to embodiment 3 of the present application is described below with reference to fig. 13 to 18D. Fig. 13 is a schematic structural view showing a zoom lens group according to embodiment 3 of the present application in a telephoto state. Fig. 14 is a schematic structural view showing an intermediate state of a zoom lens group according to embodiment 3 of the present application in switching from a telephoto state to a wide-angle state. Fig. 15 shows a schematic configuration diagram of a zoom lens group according to embodiment 3 of the present application in a wide angle state.

As shown in fig. 13-15, the zoom lens assembly, in order from an object side to an image side, comprises: a first lens group G1 (first lens E1 and second lens E2), a second lens group G2 (third lens E3 and fourth lens E4), a third lens group G3 (fifth lens E5 and sixth lens E6), a fourth lens group G4 (seventh lens E7), a filter E8, and an image plane S17.

The object-side surface S1 of the first lens element E1 is convex, and the image-side surface S2 is concave. The object-side surface S3 of the second lens element E2 is concave, and the image-side surface S4 is concave. The object-side surface S5 of the third lens element E3 is convex, and the image-side surface S6 is convex. The object-side surface S7 of the fourth lens element E4 is convex, and the image-side surface S8 is concave. The object-side surface S9 of the fifth lens element E5 is convex, and the image-side surface S10 is concave. The object-side surface S11 of the sixth lens element E6 is convex, and the image-side surface S12 is concave. The object-side surface S13 of the seventh lens element E7 is convex, and the image-side surface S14 is concave. Filter E8 has an object side S15 and an image side S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

Table 7 shows a basic parameter table of the variable focus lens package of embodiment 3, in which the unit of the radius of curvature and the thickness/distance are both millimeters (mm).

Flour mark	Surface type	Radius of curvature	Thickness/distance	Refractive index	Abbe number	Material of	Coefficient of cone
								OBJ	Spherical surface	All-round	All-round
S1	Spherical surface	8.2831	3.3927	1.91	31.4	Glass
								S2	Spherical surface	8.7411	1.0372
S3	Spherical surface	-180.7267	0.2500	1.65	58.4	Glass
								S4	Spherical surface	8.6366	D4
S5(STO)	Spherical surface	8.5320	1.0160	1.74	52.7	Glass
								S6	Spherical surface	-66.0563	0.0300
S7	Aspherical surface	22.6594	0.5000	1.67	20.4	Plastic cement	0.0000
								S8	Aspherical surface	24.3013	D8	0.0000
S9	Spherical surface	8.1849	0.7322	1.50	81.6	Glass
								S10	Spherical surface	33.6591	0.0000
S11	Spherical surface	33.6591	1.1795	1.93	20.9	Glass
								S12	Spherical surface	7.8610	D12
S13	Spherical surface	7.3827	1.2294	1.93	20.9	Glass
								S14	Spherical surface	8.1383	7.5282
S15	Spherical surface	All-round	0.2100	1.52	64.2
								S16	Spherical surface	All-round	0.2900
S17	Spherical surface	All-round

TABLE 7

Table 8 shows parameter tables of example 3 in different states of the zoom lens group, in which the units of f, TTL, ImgH, D4, D8, and D12 are all millimeters (mm), and the unit of FOV is degrees (°).

Each parameter	State of long focus	Intermediate state	Wide angle state
				f	35.33	20.00	12.89
Fno	4.19	3.01	2.45
				FOV	8.9	15.8	25.0
TTL	35.00	31.68	35.00
				ImgH	2.72	2.72	2.72
D4	0.03	5.74	13.11
				D8	0.02	0.07	0.00
D12	17.55	8.48	4.50

TABLE 8

Table 9 shows the high-order coefficient A which can be used for each aspherical mirror surface in example 3₄、A₆、A₈、A₁₀、A₁₂、A₁₄、A₁₆、A₁₈And A₂₀. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

Flour mark

A4

A6

A8

A10

A12

A14

A16

A18

A20

S7

4.9893E-05

-4.5445E-05

3.8446E-05

-1.1930E-05

2.2894E-06

-2.7422E-07

1.9950E-08

-8.0674E-10

1.3912E-11

S8

4.0672E-04

-4.6538E-05

4.5668E-05

-1.4694E-05

2.9260E-06

-3.6195E-07

2.7067E-08

-1.1185E-09

1.9572E-11

TABLE 9

Fig. 16A, 17A, and 18A show axial chromatic aberration curves in a telephoto state, an intermediate state, and a wide-angle state, respectively, of the zoom lens group of example 3, which indicate convergent focus deviations of light rays of different wavelengths after passing through the lens. Fig. 16B, 17B, and 18B show astigmatism curves representing meridional field curvature and sagittal field curvature in the telephoto state, the intermediate state, and the wide angle state, respectively, of the zoom lens group of example 3. Fig. 16C, 17C, and 18C show distortion curves of the zoom lens group of example 3 in the telephoto state, the intermediate state, and the wide-angle state, respectively, which represent values of distortion magnitudes corresponding to different image heights. Fig. 16D, 17D, and 18D show chromatic aberration of magnification curves representing deviations of different image heights on an image forming surface of light rays after passing through the lens in a telephoto state, an intermediate state, and a wide angle state, respectively, of the zoom lens group of example 3. As can be seen from fig. 16A to 18D, the zoom lens group according to embodiment 3 can achieve good imaging quality in each state.

In summary, examples 1 to 3 each satisfy the relationship shown in table 10.

Watch 10

The present application also provides an imaging device whose electron photosensitive element may be a photo-coupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device may be a stand-alone imaging device such as a digital camera, or may be an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the zoom lens group described above.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. The zoom lens assembly, in order from an object side to an image side along an optical axis, comprises:

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

a second lens group having positive optical power, including a third lens and a fourth lens;

a third lens group having optical power, including a fifth lens and a sixth lens, wherein the fifth lens and the sixth lens form a cemented lens; and

a fourth lens group having optical power, including a seventh lens;

changing a spacing distance of the first lens group and the second lens group on the optical axis, a spacing distance of the second lens group and the third lens group on the optical axis, and a spacing distance of the third lens group and the fourth lens group on the optical axis to realize switching of the zoom lens group from a telephoto state to a wide-angle state.

2. A zoom lens group according to claim 1, wherein a total effective focal length FT when the zoom lens group is in a telephoto state and a total effective focal length FW when the zoom lens group is in a wide angle state satisfy: 1.9 < FT/FW < 2.9.

3. A zoom lens group according to claim 1, wherein an effective focal length F1 of said first lens group and an effective focal length F2 of said second lens group satisfy: -2.9 < F1/F2 < -1.6.

4. A zoom lens group according to claim 1, wherein the total effective focal length FT in the telephoto state of the zoom lens group satisfies: FT is more than 29mm and less than 36 mm.

5. A zoom lens group as recited in claim 1, wherein a radius of curvature R1 of an object-side surface of the first lens, a radius of curvature R2 of an image-side surface of the first lens, and a total effective focal length FW of the zoom lens group in a wide-angle state satisfy: 1.0 < (R1+ R2)/FW < 1.5.

6. A zoom lens group according to claim 1, wherein the effective focal length f11 of the first lens, the effective focal length f12 of the second lens and the effective focal length f31 of the fifth lens satisfy: 0.8 < (f11+ f12)/f31 < 1.3.

7. A variable focus lens package as claimed in claim 1, wherein an effective focal length f21 of said third lens and a radius of curvature R5 of an object side surface of said third lens satisfy: f21/R5 is more than 0.8 and less than 1.3.

8. A zoom lens group according to claim 1, wherein a central thickness CT1 of said first lens on said optical axis and a central thickness CT7 of said seventh lens on said optical axis satisfy: 1.0 < CT1/CT7 < 2.8.

9. A zoom lens group as recited in claim 1, wherein a radius of curvature R13 of an object-side surface of said seventh lens and a radius of curvature R14 of an image-side surface of said seventh lens satisfy: 0.5 < R13/R14 < 1.0.

10. A zoom lens group according to claim 1, wherein a maximum field angle FOVW when the zoom lens group is in a wide-angle state satisfies: 20 DEG < FOVW < 26 deg.

11. The zoom lens group of claim 1, wherein at least one of the third lens and the fourth lens is a plastic lens, and at least one of an object-side surface of the third lens, an image-side surface of the third lens, an object-side surface of the fourth lens, and an image-side surface of the fourth lens is an aspheric mirror surface.

12. A variable focus lens group as claimed in claim 1, wherein a lens of at least one of said first lens group and said third lens group is a glass lens.