A phased zoom lens

Abstract

The present invention discloses a staged zoom lens, which comprises a first lens group, a second lens group and a third lens group in sequence from the object side to the image side; the first lens group has negative refractive power and is composed of a first lens, a second lens and a third lens; the paraxial image side surface of the third lens is a concave surface; during zooming, the first lens group does not move relative to the image plane; the second lens group has positive refractive power; it is composed of a fourth lens, a fifth lens and a sixth lens, the paraxial object side surface of the fourth lens is a convex surface and has positive refractive power; the image side surface of the sixth lens is a concave surface; during zooming, the second lens group moves relative to the image plane and performs zoom imaging at a set position; the third lens group has positive refractive power; the third lens is composed of a seventh lens and an eighth lens; it does not move relative to the image plane during zooming; an aperture is arranged on the object side surface of the fourth lens and moves following the second lens group.

Description

Technical Field

[0001] The present invention is a staged zoom lens, which has the technical advantages of miniaturization, high stability, easy production and higher imaging quality compared with previous zoom lenses. Background Art

[0002] Mobile phones are an extremely important information exchange tool in people's daily lives, and they are also gradually developing and improving, from a single function to gradually integrating shooting, faxing, Internet access, playback and other functions. Among them, the shooting function, as an important information input tool in mobile phones, has gradually become an important function that people care about, and has become an important basis for people to evaluate the new functions of mobile phones. In recent years, mobile phone lenses have gradually evolved, and large aperture lenses, wide-angle lenses, telephoto lenses and zoom lenses have continued to appear. Among them, zoom lenses have gradually begun to be used in mobile phones because they can switch between wide-angle lenses and telephoto lenses and take clear images.

[0003] At present, zoom lenses still have certain limitations, such as difficulty in miniaturization, high production difficulty, and high demand for motors, which makes zoom lenses only used in high-end flagship phones and cannot be applied to a wider market. This phased zoom lens adopts a phased zoom method, and only when the lens group reaches the specified position will it form an image, thereby reducing the high requirements of the lens on the motor and reducing the difficulty of lens processing, making it easier to produce. Summary of the invention

[0004] The purpose of the present invention is to solve the above technical problems and provide a staged zoom lens.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A step-by-step zoom lens, characterized in that:

[0007] The lens comprises a first lens group, a second lens group, and a third lens group in order from the object side to the image side;

[0008] The first lens group has negative refractive power and is composed of a first lens, a second lens and a third lens; the paraxial image side surface of the third lens is a concave surface; during zooming, the first lens group does not move relative to the image plane;

[0009] The second lens group has positive refractive power; it is composed of a fourth lens, a fifth lens and a sixth lens, the fourth lens has a convex surface on the paraxial object side and has positive refractive power; the image side surface of the sixth lens is a concave surface; during zooming, the second lens group is displaced relative to the image plane, and zoom imaging is performed at a set position;

[0010] The third lens group has positive refractive power; the third lens is composed of the seventh lens and the eighth lens; no displacement occurs relative to the image plane during zooming; the aperture is set on the object side surface of the fourth lens and moves with the second lens group;

[0011] When the zoom lens moves from the wide-angle position to the telephoto position, the distance between the first lens group and the second lens group decreases, and the distance between the second lens group and the third lens group increases.

[0012] The zoom lens satisfies the following formula:

[0013] OALt=OALw

[0014] This zoom lens adopts a staged zoom method, where OALt is the total optical length of the lens when the second lens group moves to the telephoto position, and OALw is the total optical length of the lens when the second lens group moves to the wide-angle position.

[0015] (R6+R7) / (R6-R7)<12

[0016] Among them, R6 is the curvature radius of the image side surface of the third lens; R7 is the curvature radius of the object side surface of the fourth lens. Under this condition, the surface curvatures of the image surface of the third lens and the object surface of the fourth lens can be controlled, which is beneficial to suppress the effective diameter of the lens and facilitate assembly.

[0017] CTt=CTw

[0018] Among them, CTt is the center distance from the p1s1 surface to the p7s1 surface in the wide-angle state; CTw is the center distance from the p1s1 surface to the p7s1 surface in the telephoto state.

[0019] In the embodiment, the first lens group of the zoom lens is composed of three plastic lenses, namely, the first lens, the second lens and the third lens, and at least one aspherical surface exists on the object side and the image side of the three lenses. Such a configuration is easy to process, low in price and can correct aberrations.

[0020] In an embodiment, the first lens group and the third lens group of the zoom lens are fixed, and zooming is performed by moving the second lens group. When this condition is met, the lens can achieve step-by-step zooming.

[0021] In an embodiment, the focal length f of the first lens group is expressed as G1 and the focal length f of the second lens group G2 Requirements:

[0022] 2.2<|f G1 / f G2 |<2.8

[0023] When this condition is met, the total length of the lens is controlled within a certain range, which can achieve miniaturization of the lens and reduce astigmatism and distortion.

[0024] In an embodiment, the total focal length fw when the zoom lens is in a wide-angle state and the total focal length fw when the zoom lens is in a telephoto state satisfy the condition:

[0025] 1 <f w / f t <2

[0026] When the lens meets this condition, the moving distance is moderate when changing from a wide-angle state to a telephoto state, thereby achieving a miniaturized zoom lens.

[0027] In an embodiment, the curvature radius R2 of the object-side surface of the first lens and the focal length F1 of the first lens satisfy the condition:

[0028] -0.05 <R2 / F1<0.05

[0029] When this condition is met, the aberration of the lens is reduced.

[0030] In the embodiment, the thickness T1 of the first lens group is expressed as, when the zoom lens is in the wide-angle state, the distance D between the first lens group and the second lens group is expressed as w12 , the distance D between the first lens group and the second lens group when the zoom lens is in telephoto state t12 , the total focal length f of the zoom lens at wide angle w Requirements:

[0031] 0.3 <T1+(D w12 -D t12 ) / f w <0.65

[0032] When this condition is met, the lens can achieve a high zoom ratio and be miniaturized.

[0033] In an embodiment, there is at least one plastic lens in the second lens group, and the aperture is located in the second lens group and moves with the lens group.

[0034] In an embodiment, the focal length F13 of the third lens and the focal length F1 of the first lens group satisfy the condition:

[0035] 1 <F13 / F1<2

[0036] When this condition is met, distortion and astigmatism can be reduced, thereby improving the imaging quality of the lens.

[0037] The advantages of the present invention are that, compared with the existing zoom lens, the present invention has the technical advantages of miniaturization, high stability, easy production and higher imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1A ,1B It is a schematic structural diagram of an optical lens according to Embodiment 1 of the present invention.

[0039] Figure 2A It is the illumination curve of the optical lens of Example 1 of the present invention in the wide-angle state.

[0040] Figure 2B It is the on-axis astigmatism curve of the optical lens of Example 1 of the present invention in the wide-angle state.

[0041] Figure 2C 3 is a distortion diagram of the optical lens of Example 1 of the present invention in a wide-angle state.

[0042] Figure 3A : is the illumination curve of the optical lens of Example 1 of the present invention in the telephoto state.

[0043] Figure 3B axial astigmatism curve of the optical lens in Example 1 of the present invention in the telephoto state.

[0044] Figure 3C 3 is a distortion diagram of the optical lens of Example 1 of the present invention in a telephoto state.

[0045] Figure 4A , 4B It is a schematic structural diagram of an optical lens according to Embodiment 2 of the present invention.

[0046] Figure 5A 1 is an illumination curve of the optical lens of Example 2 of the present invention in a wide-angle state.

[0047] Figure 5B 3 is an on-axis astigmatism curve of the optical lens of Example 2 of the present invention in a wide-angle state.

[0048] Figure 5C 3 is a distortion diagram of the optical lens of Example 2 of the present invention in a wide-angle state.

[0049] Fig. 6A : is the illumination curve of the optical lens of Example 2 of the present invention in the telephoto state.

[0050] Figure 6B axial astigmatism curve of the optical lens in Example 2 of the present invention in the telephoto state.

[0051] Figure 6C 3 is a distortion diagram of the optical lens of Example 2 of the present invention in a telephoto state.

[0052] Fig. 7A , 7B It is a schematic structural diagram of an optical lens according to Embodiment 3 of the present invention.

[0053] Fig. 8A3 is an illumination curve of the optical lens of Example 3 of the present invention in a wide-angle state.

[0054] Figure 8B 3 is an on-axis astigmatism curve of the optical lens of Example 3 of the present invention in a wide-angle state.

[0055] Figure 8C 3 is a distortion diagram of the optical lens of Example 3 of the present invention in a wide-angle state.

[0056] Fig. 9A : is the illumination curve of the optical lens of Example 3 of the present invention in the telephoto state.

[0057] Fig. 9B 3 is an on-axis astigmatism curve of the optical lens in Example 3 of the present invention in a telephoto state.

[0058] Fig. 9C 3 is a distortion diagram of the optical lens of Example 3 of the present invention in a telephoto state. DETAILED DESCRIPTION

[0059] Example 1

[0060] The following reference Figure 1A , 1B This is a two-dimensional diagram of an optical lens according to Example 1 of the present application.

[0061] like Figure 1A , 1B As shown, the optical lens according to the exemplary embodiment of the present application includes, from the object side to the image side along the optical axis: the first lens group has negative refractive power; the second lens group has positive refractive power; the third lens group has positive refractive power; the filter has an object side surface and an image side surface. The incident light passes through each lens surface in sequence and finally forms an image on the imaging surface.

[0062] Table 1 shows the surface type, curvature radius, thickness and material of each lens of the optical lens of Example 1. The units of the curvature radius and thickness are both millimeters (mm).

[0063] In this embodiment, please refer to the following table for specific design parameters:

[0064] Table 1(a)

[0065] lens Surface serial number Surface type Radius of curvature thickness Material properties (Nd:Vd) thing Spherical Inf Inf P1 1 Aspheric 6.5021 0.86 544000.560000 2 Aspheric 6.3801 0.20 P2 3 Aspheric 6.5471 0.50 544000.560000 4 Aspheric 4.4278 0.20 P3 5 Aspheric 7.6420 2.53 634000.239000 Wide angle position 6 Aspheric 5.3462 5.20 Telephoto position 6 Aspheric 5.3462 1.30 P4 aperture 7 Aspheric 4.4758 2.20 535200.561150 8 Aspheric -6.0779 0.22 P5 9 Aspheric -7.99 0.50 661200.203540 10 Aspheric -8.2454 1.60 P6 11 Aspheric -118.2331 1.14 634000.239000 Wide angle position 12 Aspheric 4.9977 6.23 Telephoto position 12 Aspheric 4.9977 10.13 P7 13 Aspheric -12.4432 0.60 544000.560000 14 Aspheric 11.2394 0.76 P8 15 Aspheric 22.9154 1.18 634000.239000 16 Aspheric -5.6785 0.78 IR 17 Spherical Inf 0.21 BK7_SCHOTT 18 Spherical Inf 1.10 picture Spherical Inf 0

[0066] Table 1(b)

[0067] Face number K A4 A6 A8 A10 A12 A14 A16 S1 -3.60E+00 -2.49E-01 -1.66E-02 5.98E-03 -3.50E-03 1.53E-03 -2.66E-03 5.68E-04 S2 1.72E-01 -1.63E-02 -2.82E-02 -2.62E-02 -4.77E-03 -1.59E-03 -5.78E-03 1.85E-03 S3 -2.02E+00 -1.11E-01 -6.81E-02 -2.95E-02 3.31E-03 -2.61E-03 -2.69E-03 1.31E-03 S4 -2.43E+00 -2.37E-01 -1.15E-01 1.81E-02 -7.33E-03 6.52E-03 -4.24E-03 1.93E-03 S5 5.50E+00 3.61E-02 -9.47E-02 1.01E-02 -1.54E-02 5.10E-03 -4.82E-03 1.35E-03 S6 -4.23E+00 1.29E-01 1.95E-03 1.74E-03 -1.07E-03 3.94E-04 -2.30E-04 1.20E-04 S7 -6.50E-02 2.33E-02 4.10E-03 1.81E-03 2.27E-04 4.78E-05 9.66E-08 4.43E-05 S8 -2.45E+00 3.75E-02 5.69E-03 5.21E-03 2.46E-03 -1.82E-03 1.03E-03 -2.30E-04 S9 1.62E+00 -3.80E-02 5.86E-03 7.46E-03 4.69E-03 -3.65E-03 1.48E-03 -3.90E-04 S10 -8.02E+00 -4.45E-03 -1.23E-02 7.15E-03 3.14E-03 -2.04E-03 6.22E-04 -1.40E-04 S11 -2.52E+01 4.17E-03 -2.83E-02 2.83E-03 2.10E-04 -4.68E-05 0.00E+00 0.00E+00 S12 -1.65E+00 4.76E-02 -1.55E-02 1.81E-03 1.41E-04 -3.49E-05 0.00E+00 0.00E+00 S13 3.16E+00 1.97E-01 -1.35E-02 -1.06E-03 -2.10E-04 -7.41E-05 0.00E+00 0.00E+00 S14 1.08E+01 1.67E-01 -3.57E-02 3.48E-03 -2.63E-03 -1.90E-04 0.00E+00 0.00E+00 S15 8.46E+01 9.51E-02 -6.96E-02 1.75E-02 -1.35E-03 -3.20E-04 -2.70E-04 0.00E+00 S16 5.52E-01 1.11E-01 -6.20E-02 1.62E-02 5.74E-04 -4.95E-05 -5.36E-05 0.00E+00

[0068] In this embodiment, the lens meets the requirements, and its specific parameters are shown in the following table:

[0069] Table 1(c)

[0070]

[0071] According to Table 1(a), Table 1(b) and Figure 1A , 1B , the lens shape and various properties of the lens of the current embodiment are more clearly displayed, indicating that the current embodiment is a camera lens that can achieve staged zoom.

[0072] According to Table 1(c) Figure 2A In the illumination curve of the lens in the wide-angle state, after the lens meets the requirements, the illumination value drop value of the edge field of view of the lens is small, which shows that the illumination distribution of the picture taken by the current embodiment is uniform, and a complete image can be taken.

[0073] According to Table 1(c) Figure 2B The astigmatism curve of the medium lens in the wide-angle state is clearly shown. After the lens meets the requirements, the maximum difference between the astigmatism S line and T line of the lens is about 0.02mm, indicating that the lens has a good ability to improve astigmatism.

[0074] According to Table 1(c) Figure 2C The distortion curve of the medium lens in wide-angle state shows more clearly that after the lens meets the requirements, the maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

[0075] According to Table 1(c) Figure 3A In the illumination curve of the lens in the telephoto state, after the lens meets the requirements, the illumination value drop value of the edge field of view of the lens is small, which shows that the illumination distribution of the picture taken by the current embodiment is uniform, and a complete image can be taken.

[0076] According to Table 1(c) Figure 3B The astigmatism curve of the medium lens in the telephoto state is clearly shown. After the lens meets the requirements, the maximum difference between the astigmatism S line and T line of the lens is about 0.06mm, indicating that the lens has a good ability to improve astigmatism.

[0077] According to Table 1(c) Figure 3C The distortion curve of the medium lens in telephoto state shows more clearly that when the lens meets the full requirements, the maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

[0078] Example 2

[0079] The following reference Figure 4A , 4B This is a two-dimensional diagram of an optical lens according to Example 2 of the present application.

[0080] like Figure 4A ,4B As shown, the optical lens according to the exemplary embodiment of the present application includes, from the object side to the image side along the optical axis: the first lens group has negative refractive power; the second lens group has positive refractive power; the third lens group has positive refractive power; the filter has an object side surface and an image side surface. The incident light passes through each lens surface in sequence and finally forms an image on the imaging surface.

[0081] Table 2 shows the surface type, curvature radius, thickness and material of each lens of the optical lens of Example 2. The units of the curvature radius and thickness are both millimeters (mm).

[0082] In this embodiment, please refer to the following table for specific design parameters:

[0083] Table 2(a)

[0084]

[0085]

[0086] Table 2(b)

[0087]

[0088] In this embodiment, the lens meets the requirements, and its specific parameters are shown in the following table:

[0089] Table 2(c)

[0090]

[0091] According to Table 2(a), Table 2(b) and Figure 4A , 4B , the lens shape and various properties of the lens of the current embodiment are more clearly displayed, indicating that the current embodiment is a camera lens that can achieve staged zoom.

[0092] According to Table 2(c) Figure 5A In the illumination curve of the lens in the wide-angle state, after the lens meets the requirements, the illumination value drop value of the edge field of view of the lens is small, which shows that the illumination distribution of the picture taken by the current embodiment is uniform, and a complete image can be taken.

[0093] According to Table 2(c) Figure 5B The astigmatism curve of the medium lens in the wide-angle state is clearly shown. After the lens meets the requirements, the maximum difference between the astigmatism S line and T line of the lens is about 0.1mm, indicating that the lens has a good ability to improve astigmatism.

[0094] According to Table 1(c) Figure 5CThe distortion curve of the medium lens in wide-angle state shows more clearly that after the lens meets the requirements, the maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

[0095] According to Table 2(c) Fig. 6A In the illumination curve of the lens in the telephoto state, after the lens meets the requirements, the illumination value drop value of the edge field of view of the lens is small, which shows that the illumination distribution of the picture taken by the current embodiment is uniform, and a complete image can be taken.

[0096] According to Table 2(c) Figure 6B The astigmatism curve of the medium lens in the telephoto state is clearly shown. After the lens meets the requirements, the maximum difference between the astigmatism S line and T line of the lens is about 0.1mm, indicating that the lens has a good ability to improve astigmatism.

[0097] According to Table 1(c) Figure 6C The distortion curve of the medium lens in the telephoto state shows more clearly that after the lens meets the requirements, the maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

[0098] Example 3

[0099] The following reference Fig. 7A , 7B This is a two-dimensional diagram of the optical lens according to Example 3 of the present application.

[0100] like Fig. 7A , 7B As shown, the optical lens according to the exemplary embodiment of the present application includes, from the object side to the image side along the optical axis: the first lens group has negative refractive power; the second lens group has positive refractive power; the third lens group has positive refractive power; the filter has an object side surface and an image side surface. The incident light passes through each lens surface in sequence and finally forms an image on the imaging surface.

[0101] Table 3 shows the surface type, curvature radius, thickness and material of each lens of the optical lens of Example 3. The units of the curvature radius and thickness are both millimeters (mm).

[0102] Please refer to the following table for the specific design parameters of the lens assembly of this embodiment:

[0103] Table 3(a)

[0104]

[0105]

[0106] Table 3(b)

[0107] Face number K A4 A6 A8 A10 A12 A14 A16 S1 -3.64E+00 -1.45E-01 -1.38E-02 4.11E-03 -2.10E-03 1.78E-03 -1.42E-03 4.13E-04 S2 2.24E-01 -2.04E-02 -3.31E-02 -1.77E-02 -2.68E-03 -4.80E-04 -4.07E-03 1.30E-03 S3 -2.05E+00 -1.30E-01 -7.23E-02 -3.17E-02 4.79E-03 -1.60E-03 -2.53E-03 8.76E-04 S4 -1.58E+00 -2.55E-01 -1.19E-01 1.67E-02 -6.86E-03 8.15E-03 -5.07E-03 1.59E-03 S5 4.69E+00 5.18E-03 -8.96E-02 9.62E-03 -1.52E-02 6.04E-03 -4.74E-03 8.40E-04 S6 -4.34E+00 1.12E-01 8.35E-04 1.03E-03 -7.50E-04 2.88E-04 -1.40E-04 5.86E-05 S7 -6.20E-02 1.48E-02 3.30E-03 2.90E-04 3.77E-05 -1.40E-04 -5.90E-05 9.88E-06 S8 -2.46E+00 2.22E-02 5.45E-04 7.09E-04 2.64E-03 -2.28E-03 9.15E-04 -2.00E-04 S9 1.49E+00 -3.56E-02 -2.25E-03 3.41E-03 4.10E-03 -3.36E-03 1.23E-03 -3.00E-04 S10 -6.34E+00 -3.70E-03 -1.18E-02 3.50E-03 3.36E-03 -1.68E-03 4.65E-04 -1.10E-04 S11 -2.52E+01 2.66E-02 -2.66E-02 1.39E-03 7.30E-04 -9.43E-05 1.05E+00 0.00E+00 S12 -1.13E+00 5.78E-02 -1.41E-02 1.08E-03 3.47E-04 -6.98E-05 2.00E+00 0.00E+00 S13 -1.93E+00 2.16E-01 -4.99E-04 -8.21E-03 2.64E-03 -6.00E-04 0.00E+00 0.00E+00 S14 8.58E+00 2.30E-01 -3.74E-02 -3.80E-03 -5.40E-04 -1.29E-04 0.00E+00 0.00E+00 S15 7.44E+01 2.48E-01 -1.22E-01 1.34E-02 -6.62E-03 -4.30E-04 -5.00E-04 0.00E+00 S16 -2.21E-01 4.86E-01 -1.56E-01 1.58E-02 -7.59E-03 -1.93E-03 -3.90E-04 0.00E+00

[0108] In this embodiment, the lens meets the requirements, and its specific parameters are shown in the following table:

[0109] Table 3(c)

[0110]

[0111] According to Table 3(a), Table 3(b) and Fig. 7A , 7B , the lens shape and various properties of the lens of the current embodiment are more clearly displayed, indicating that the current embodiment is a camera lens that can achieve staged zoom.

[0112] According to Table 3(c) Fig. 8A In the illumination curve of the lens in the wide-angle state, after the lens meets the requirements, the illumination value drop value of the edge field of view of the lens is small, which shows that the illumination distribution of the picture taken by the current embodiment is uniform, and a complete image can be taken.

[0113] According to Table 3(c) Figure 8B The astigmatism curve of the medium lens in the wide-angle state shows more clearly that after the lens meets the requirements of the claims, the maximum difference between the astigmatism S line and T line of the lens is about 0.03mm, indicating that the lens has a good ability to improve astigmatism.

[0114] According to Table 1(c) Figure 8C The distortion curve of the medium lens in wide-angle state shows more clearly that after the lens meets the requirements, the maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

[0115] According to Table 3(c) Fig. 9A In the illumination curve of the lens in the telephoto state, after the lens meets the requirements, the illumination value drop value of the edge field of view of the lens is small, which shows that the illumination distribution of the picture taken by the current embodiment is uniform, and a complete image can be taken.

[0116] According to Table 3(c) Fig. 9B The astigmatism curve of the medium lens in the telephoto state is clearly shown. After the lens meets the requirements, the maximum difference between the astigmatism S line and T line of the lens is about 0.06mm, indicating that the lens has a good ability to improve astigmatism.

[0117] According to Table 1(c) Fig. 9C The distortion curve of the medium lens in the telephoto state shows more clearly that after the lens meets the requirements, the maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

Claims

1. A step-by-step zoom lens, characterized in that: From the object side to the image side, it includes the first lens group, the second lens group, and the third lens group; The first lens group has negative refractive power and is composed of a first lens, a second lens and a third lens; the paraxial image side surface of the third lens is a concave surface; during zooming, the first lens group does not move relative to the image plane; The second lens group has positive refractive power and is composed of a fourth lens, a fifth lens and a sixth lens, wherein the fourth lens has a convex surface on the paraxial object side and has positive refractive power; The image side surface of the sixth lens is a concave surface; during zooming, the second lens group is displaced relative to the image plane, and zoom imaging is performed at a set position; The third lens group has positive refractive power; the third lens is composed of the seventh lens and the eighth lens; and no displacement occurs relative to the image plane during zooming; The aperture stop is arranged on the object side surface of the fourth lens element and moves following the second lens group; When the zoom lens moves from the wide-angle position to the telephoto position, the distance between the first lens group and the second lens group decreases, and the distance between the second lens group and the third lens group increases; The first lens group and the third lens group are fixed, there is at least one plastic lens in the second lens group, and the aperture is located in the second lens group and moves with the lens group; The first lens, the second lens and the third lens are plastic lenses, and at least one aspherical surface exists on the object side and the image side of the three lenses; The zoom lens satisfies the following formula: OALt=OALw This zoom lens adopts a staged zoom method, where OALt is the total optical length of the lens when the second lens group moves to the telephoto position, and OALw is the total optical length of the lens when the second lens group moves to the wide-angle position; (R6+R7) / (R6-R7)<12 Wherein, R6 is the curvature radius of the image side surface of the third lens; R7 is the curvature radius of the object side surface of the fourth lens; CTt=CTw Wherein, CTt is the distance between the object side surface of the first lens and the center of the object side surface of the seventh lens in the wide-angle state; CTw is the distance between the object side surface of the first lens and the center of the object side surface of the seventh lens in the telephoto state.

2. The step-by-step zoom lens according to claim 1, wherein: The following relationship is also satisfied: 2.2<|fG1 / fG2|<2.8 Wherein, fG1 is the focal length of the first lens group, in millimeters, and fG2 is the focal length of the second lens group, in millimeters.

3. The step-by-step zoom lens according to claim 1, wherein: The following relationship is also satisfied: 0.59 <fw / ft<0.65 Wherein, fw is the total focal length of the zoom lens when it is in the wide-angle state, and ft is the total focal length of the zoom lens when it is in the telephoto state.

4. The step-by-step zoom lens according to claim 1, wherein: The following relationship is also satisfied: -0.05 <R2 / F1<0.05 Wherein, R2 is the radius of curvature of the object side surface of the first lens, and F1 is the focal length of the first lens.

5. The step-by-step zoom lens according to claim 1, wherein: The following relationship is also satisfied: 0.3 <T1+(Dw12-Dt12) / fw<0.65 Among them, T1 is the thickness of the first lens group, Dw12 is the distance between the first lens group and the second lens group when the zoom lens is in the wide-angle state; Dt12 is the distance between the first lens group and the second lens group when the zoom lens is in the telephoto state; fw is the total focal length of the zoom lens in the wide-angle state.

6. The step-by-step zoom lens according to claim 1, wherein: The following relationship is also satisfied: 1 <F13 / F1<2 Wherein, F13 is the focal length of the third lens, in millimeters, and F1 is the focal length of the first lens group, in millimeters.

Images