Zoom lens

Abstract

The application discloses a zoom lens, which comprises two lens groups in sequence from the object side to the image side along the optical axis, i.e. a focusing lens group with negative focal power and a zoom lens group with positive focal power; the focusing lens group comprises three lenses in sequence along the optical axis, i.e. a first lens with negative focal power, a second lens with negative focal power and a third lens with positive or negative focal power; the zoom lens group comprises four lenses in sequence along the optical axis, i.e. a fourth lens with positive focal power, a fifth lens with negative focal power, a sixth lens with positive focal power and a seventh lens with negative focal power, or a fourth lens with positive focal power, a fifth lens with positive focal power, a sixth lens with negative focal power and a seventh lens with positive focal power.

Description

Technical Field

[0001] This application relates to the field of optical devices, specifically to a zoom lens. Background Technology

[0002] In recent years, with social development, optical lenses have been widely used in fields such as vehicle monitoring, mobile phone lenses, video conferencing, and security monitoring. Although zoom lenses can achieve images with different magnification levels, compared to fixed-focus lenses, they often require a larger lens size and a more complex internal structure, resulting in generally higher costs.

[0003] Existing zoom lenses generally suffer from the following technical problems:

[0004] 1. The overall optical length is relatively long and the volume is relatively large, which makes the overall cost and weight of the lens too high;

[0005] 2. The small aperture results in insufficient brightness when shooting in low-light conditions, making the image unclear.

[0006] 3. It is difficult to adapt to the all-weather monitoring needs, including daytime, dusk, and nighttime.

[0007] Therefore, given the current state of zoom lens development, zoom lenses that are miniaturized, low-cost, have a large aperture, and infrared confocal are among the current market demands. Summary of the Invention

[0008] This application provides a zoom lens, which sequentially comprises, along the optical axis from the object side to the image side: a focusing lens group with negative optical power and a zoom lens group with positive optical power, for a total of two lens groups; the focusing lens group sequentially comprises, along the optical axis from the object side to the image side: a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power, for a total of three lenses; or a first lens with negative optical power, a second lens with negative optical power, and a third lens with negative optical power, for a total of three lenses; the zoom lens group sequentially comprises, along the optical axis from the object side to the image side: Includes: a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power, totaling four lenses; or a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, and a seventh lens with positive optical power, totaling four lenses; the zoom lens satisfies the following condition: 3.60≤TTL-w / BFL-w≤5.24; where TTL-w is the total optical length at the wide-angle end of the zoom lens, and BFL-w is the back focal length at the wide-angle end of the zoom lens.

[0009] According to an exemplary embodiment of this application, the object-side surface of the first lens is convex and the image-side surface is concave; the object-side surface of the second lens is concave and the image-side surface is either convex or concave; the object-side surface of the third lens is convex and the image-side surface is concave; the object-side surface of the fourth lens is convex and the image-side surface is convex; the object-side surface of the fifth lens is concave and the image-side surface is concave; the object-side surface of the sixth lens is convex and the image-side surface is convex; and the object-side surface of the seventh lens is convex and the image-side surface is concave.

[0010] According to an exemplary embodiment of this application, the object-side surface of the first lens is convex and the image-side surface is concave; the object-side surface of the second lens is concave and the image-side surface is convex; the object-side surface of the third lens is convex and the image-side surface is concave; the object-side surface of the fourth lens is convex and the image-side surface is concave; the object-side surface of the fifth lens is convex and the image-side surface is convex; the object-side surface of the sixth lens is concave and the image-side surface is concave; and the object-side surface of the seventh lens is convex and the image-side surface is convex.

[0011] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: -0.27≤(R41+R42) / F4≤0.94; 1.63≤(F4-F5) / FG2≤2.91; -2.79≤F5 / Fw≤1.98; -1.59≤F5 / FG2≤0.99; 1.40≤(Nd4+Nd5) / 2≤1.82; 49.72≤(Vd4+V d5) / 2≤65.96; where R41 is the radius of curvature of the object side of the fourth lens, R42 is the radius of curvature of the image side of the fourth lens, F4 is the focal length of the fourth lens, F5 is the focal length of the fifth lens, FG2 is the focal length of the zoom lens group, Fw is the focal length of the wide-angle end of the zoom lens, Nd4 is the refractive index of the fourth lens, Nd5 is the refractive index of the fifth lens, Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens.

[0012] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: 1.29≤F4 / Fw≤6.18; 1.38≤F45 / Fw≤7.62; -1.41≤FG1 / FG2≤-0.73; 1.13≤F2 / FG1≤9.99; 0.34≤G2-L / G1-L≤0.96; where F4 is the focal length of the fourth lens, Fw is the focal length at the wide-angle end of the zoom lens, F45 is the combined focal length of the fourth and fifth lenses, FG1 is the focal length of the focusing lens group, FG2 is the focal length of the zoom lens group, F2 is the focal length of the second lens, G1-L is the displacement of the focusing lens group from the wide-angle end to the telephoto end along the optical axis, and G2-L is the displacement of the zoom lens group from the wide-angle end to the telephoto end along the optical axis.

[0013] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: 3.14≤TTL-t / BFL-t≤4.69; 0.24≤IC / TTL-w≤0.31; -3.44≤(R21+R22) / F2≤1.07; -3.37≤(R31+R32) / FG1≤-1.62; -0.91≤(R12-R21) / F1≤-0.63; 9.53≤T0 / D0≤19.54; where TTL-t is the total optical length at the telephoto end of the zoom lens, and BFL-t is the length of the zoom lens. The telephoto end is the back focal length, IC is the image plane diameter of the zoom lens, TTL-w is the total optical length of the zoom lens at the wide-angle end, R21 is the radius of curvature of the object side of the second lens, R22 is the radius of curvature of the image side of the second lens, F2 is the focal length of the second lens, R31 is the radius of curvature of the object side of the third lens, R32 is the radius of curvature of the image side of the third lens, FG1 is the focal length of the focusing lens group, R12 is the radius of curvature of the image side of the first lens, F1 is the focal length of the first lens, T0 is the sum of the center thicknesses of the positive lenses of the zoom lens, and D0 is the center thickness of the last negative lens of the zoom lens.

[0014] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: 1.02≤Ft / Fw≤1.31; 0.88≤F1 / FG1≤2.05; -2.23≤FG1 / Fw≤-1.45; 1.43≤FG2 / Fw≤2.24; -0.93≤F6 / FG2≤0.94; -2.76≤F7 / FG2≤1.13; 1.26≤FG2 / Ft≤1.89; wherein, Ft is the focal length at the telephoto end of the zoom lens, Fw is the focal length at the wide-angle end of the zoom lens, F1 is the focal length of the first lens, FG1 is the focal length of the focusing lens group, FG2 is the focal length of the zoom lens group, F6 is the focal length of the sixth lens, and F7 is the focal length of the seventh lens.

[0015] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: -0.246≤(R41+R42) / F4≤0.856; 1.816≤(F4-F5) / FG2≤2.644; -2.538≤F5 / Fw≤1.804; -1.443≤F5 / FG2≤0.902; 1.55≤(Nd4+Nd5) / 2≤1.65; 55.25≤(Vd4+Vd5) / 2≤59.97; 3.998≤TTL-w / BFL-w≤4.762; 3.491≤TTL-t / BFL-t≤4.264; 0.267≤IC / TTL-w≤0.284; -3.125≤(R21+R22) / F2≤0.971; -3.064≤(R31+R32) / FG1≤-1.805; -0.827≤(R12-R21) / F1≤-0.704; 10.587≤T0 / D0≤17.760; where R41 is the radius of curvature of the object side of the fourth lens, R42 F4 is the radius of curvature of the image side of the fourth lens, F5 is the focal length of the fourth lens, FG2 is the focal length of the zoom lens group, Fw is the focal length at the wide-angle end of the zoom lens, Nd4 is the refractive index of the fourth lens, Nd5 is the refractive index of the fifth lens, Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens; TTL-w is the total optical length at the wide-angle end of the zoom lens, BFL-w is the back focal length at the wide-angle end of the zoom lens; TTL-t is the total optical length at the telephoto end of the zoom lens, and BFL-t is the focal length of the zoom lens. The focal length at the telephoto end of the zoom lens is: IC is the image plane diameter of the zoom lens; R21 is the radius of curvature of the object side of the second lens; R22 is the radius of curvature of the image side of the second lens; F2 is the focal length of the second lens; R31 is the radius of curvature of the object side of the third lens; R32 is the radius of curvature of the image side of the third lens; FG1 is the focal length of the focusing lens group; R12 is the radius of curvature of the image side of the first lens; F1 is the focal length of the first lens; T0 is the sum of the center thicknesses of the positive lenses of the zoom lens; and D0 is the center thickness of the last negative lens of the zoom lens.

[0016] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: 1.438≤F4 / Fw≤5.621; 1.539≤F45 / Fw≤6.929; -1.281≤FG1 / FG2≤-0.807; 1.261≤F2 / FG1≤9.078; 0.374≤G2-L / G1-L≤0.877; 1.132≤Ft / Fw≤1.190; 0.978≤F1 / FG1≤1.862; -2.030≤FG1 / Fw≤-1.615; 1.585≤FG2 / Fw≤2.037; -0.844≤F6 / FG2≤0. 858; -2.512≤F7 / FG2≤1.028; 1.400≤FG2 / Ft≤1.714; where F4 is the focal length of the fourth lens, Fw is the focal length of the zoom lens at the wide-angle end, F45 is the combined focal length of the fourth and fifth lenses, FG1 is the focal length of the focusing lens group, FG2 is the focal length of the zoom lens group, F2 is the focal length of the second lens, G1-L is the displacement of the focusing lens group along the optical axis from the wide-angle end to the telephoto end, G2-L is the displacement of the zoom lens group along the optical axis from the wide-angle end to the telephoto end; Ft is the focal length of the zoom lens at the telephoto end, F1 is the focal length of the first lens, F6 is the focal length of the sixth lens, and F7 is the focal length of the seventh lens. Attached Figure Description

[0017] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. In the drawings:

[0018] Figure 1 A schematic diagram of the zoom lens according to Embodiment 1 of this application when it is at the wide-angle end is shown;

[0019] Figure 2 A schematic diagram of the zoom lens according to Embodiment 1 of this application when it is at the telephoto end is shown;

[0020] Figure 3 A schematic diagram of the zoom lens at the wide-angle end according to Embodiment 2 of this application is shown;

[0021] Figure 4 A schematic diagram of the zoom lens according to Embodiment 2 of this application when it is at the telephoto end is shown;

[0022] Figure 5 A schematic diagram of the zoom lens according to Embodiment 3 of this application when it is at the wide-angle end is shown;

[0023] Figure 6 A schematic diagram of the zoom lens according to Embodiment 3 of this application is shown when it is at the telephoto end;

[0024] Figure 7 A schematic diagram of the zoom lens according to Embodiment 4 of this application when it is at the wide-angle end is shown;

[0025] Figure 8 A schematic diagram of the zoom lens according to Embodiment 4 of this application is shown when it is at the telephoto end.

[0026] Figure 9 A schematic diagram of the zoom lens according to Embodiment 5 of this application when it is at the wide-angle end is shown; and

[0027] Figure 10 A schematic diagram of the zoom lens according to Embodiment 5 of this application when it is at the telephoto end is shown. Detailed Implementation

[0028] To better understand this application, various aspects of this application will be described in detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of this application and are not intended to limit the scope of this application in any way.

[0029] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not drawn strictly to scale.

[0030] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity 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 location of the concaveness 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 subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0031] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprises," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. It should be noted that the longitudinal direction stated herein is perpendicular to the optical axis.

[0032] Unless otherwise specified, all terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Terms shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly stated herein.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] According to an exemplary embodiment of this application, a zoom lens includes a focusing lens group and a zoom lens group sequentially along the optical axis from the object side to the image side.

[0035] In an exemplary embodiment, the focusing lens group of the zoom lens has a negative optical power, which moves along the optical axis from the object side to the image side to compensate for the change in the position of the imaging plane during zooming, so that the zoom lens has a better imaging position and stable imaging quality during zooming.

[0036] In an exemplary embodiment, the focusing lens group includes a first lens, a second lens, and a third lens sequentially along the optical axis from the object side to the image side.

[0037] In an exemplary embodiment, the first lens may have negative optical power, with its object-side surface being convex and its image-side surface being concave. The first lens having negative optical power, a convex object-side surface, and a concave image-side surface can diffuse large field-of-view light rays entering the optical system to the rear optical system, effectively increasing light transmission and improving resolution.

[0038] In an exemplary embodiment, the second lens may have negative optical power, and its object-side surface may be concave, while its image-side surface may be convex or concave. The concave object-side surface of the second lens facilitates better reception of incoming light, resulting in a smoother light transition, reduced light sensitivity, and improved resolution; it also helps correct aberrations.

[0039] In an exemplary embodiment, the third lens may have positive or negative optical power, and its object-side surface may be convex, while its image-side surface may be concave. The third lens has positive optical power, and its convex object-side surface further converges the light rays entering the second lens, reducing the front aperture; its concave image-side surface receives the converged light rays and appropriately diverges them, which helps increase light transmission, improves the illumination of the edge field of view, and also helps reduce spherical aberration, thus improving image quality.

[0040] In an exemplary embodiment, the zoom lens group of the zoom lens is of positive optical power and moves along the optical axis from the image side to the object side to realize the effective focal length switching activity of the zoom lens between the wide-angle end and the telephoto end.

[0041] In an exemplary embodiment, the zoom lens group includes a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially along the optical axis from the object side to the image side.

[0042] In an exemplary embodiment, the fourth lens may have positive optical power, and its object-side surface may be convex, while its image-side surface may be either convex or concave. The convex object-side surface of the fourth lens, when paired with the fifth lens, facilitates the correction of aperture aberrations, increases the aperture, and simultaneously achieves infrared confocal focusing.

[0043] In an exemplary embodiment, the fifth lens may have negative optical power, and its object-side surface may be concave, as may its image-side surface. The concave object-side and concave image-side surfaces of the fifth lens can appropriately diverge converging light rays, making the light transition smoother, thereby reducing aberrations and improving the resolving power of the optical system; when used in conjunction with the fourth lens, it corrects aperture aberrations, increases the aperture, and simultaneously achieves infrared confocal focusing.

[0044] In an exemplary embodiment, the fifth lens may have positive optical power, and its object-side surface may be convex, as may its image-side surface. The convexity of both the object-side and image-side surfaces of the fifth lens facilitates further convergence of forward light rays, resulting in a smoother light transition and reduced aberrations. This is beneficial for miniaturization of the rear end and achieving high resolution, thereby improving the resolving power of the optical system. Combined with the fourth lens, it helps balance high and low temperatures and correct spherical aberration and coma.

[0045] In an exemplary embodiment, the sixth lens may have positive optical power, and both its object-side and image-side surfaces may be convex. The convexity of both the object-side and image-side surfaces of the sixth lens is beneficial for correcting residual field curvature in the system and improving resolution. When paired with the seventh lens, it helps to balance high and low temperatures.

[0046] In an exemplary embodiment, the sixth lens may have negative optical power, and both its object-side and image-side surfaces may be concave. The concave object-side and concave image-side surfaces of the sixth lens, when paired with the seventh lens, facilitate the balancing of high and low temperatures.

[0047] In an exemplary embodiment, the seventh lens may have negative optical power, and its object-side surface may be convex, while its image-side surface may be concave. The convex object-side surface and concave image-side surface of the seventh lens are beneficial for correcting residual spherical aberration. When the subsequent lens group increases the image height, it avoids a large angle of incidence of light on the surface. Combined with the sixth lens, it helps to balance high and low temperatures.

[0048] In an exemplary embodiment, the seventh lens may have positive optical power, and both its object-side and image-side surfaces may be convex. The convexity of both the object-side and image-side surfaces of the seventh lens effectively controls the direction of light, reducing the exit angle of light passing through the seventh lens, thereby decreasing the CRA (Current Aperture Ratio). This facilitates better matching with the chip and, when paired with the sixth lens, helps balance high and low temperatures.

[0049] In an exemplary embodiment, the zoom lens may further include an aperture stop. The aperture stop may be located between the third lens and the fourth lens, which can effectively limit the amount of light entering the optical system, shorten the overall optical length of the zoom lens, reduce the maximum optical aperture of the zoom lens, and facilitate the miniaturization of the zoom lens.

[0050] In an exemplary embodiment, the optical lens of this application may, as needed, include a filter and / or protective glass disposed between the seventh lens and the imaging surface. The filter can filter light of different wavelengths, and the protective glass can prevent damage to components (e.g., chips) on the second side of the optical lens.

[0051] In an exemplary embodiment, the first to seventh lenses can be spherical lenses or aspherical lenses. This application does not specifically limit the number of spherical and aspherical lenses; when image quality is paramount, the number of aspherical lenses can be increased, and even all lenses can be aspherical. Aspherical lenses are characterized by a continuously changing curvature from the lens center to the periphery. Unlike spherical lenses, which have a constant curvature from the lens center to the periphery, aspherical lenses have better radius of curvature characteristics, offering advantages in improving distortion and astigmatism. Using aspherical lenses can minimize aberrations that occur during imaging, thereby improving the lens's image quality. The use of aspherical lenses helps correct system aberrations and improves resolving power.

[0052] In an exemplary embodiment, the first to seventh lenses can be glass lenses or plastic lenses. This application does not specifically limit the exact number of glass lenses and plastic lenses. Optical lenses made of glass can suppress the shift in the back focus of the optical lens due to temperature changes, thereby improving system stability. Simultaneously, using glass avoids problems such as lens blurring caused by high and low temperature changes in the operating environment, and prevents problems affecting the normal use of the lens. Specifically, when temperature performance is a primary concern, the first to seventh lenses can all be made of glass. In applications with lower temperature stability requirements, the first to seventh lenses in the optical lens can also all be made of plastic. Using plastic to make optical lenses can effectively reduce manufacturing costs. Of course, the first to seventh lenses in the optical lens can also be made of a combination of plastic and glass.

[0053] In an exemplary embodiment, the zoom lens can satisfy the following condition: 3.60 ≤ TTL-w / BFL-w ≤ 5.24, where TTL-w is the total optical length at the wide-angle end of the zoom lens, and BFL-w is the back focal length at the wide-angle end of the zoom lens. By making the zoom lens satisfy the above condition, the ratio range of the total optical length and back focal length at the wide-angle end of the zoom lens is controlled, which is beneficial for making the zoom lens compatible with most lens products. Preferably, the zoom lens can further satisfy the following condition: 3.998 ≤ TTL-w / BFL-w ≤ 4.762, which is even more beneficial for the zoom lens to be compatible with most lens products.

[0054] In an exemplary embodiment, the zoom lens can satisfy the following condition: -0.27 ≤ (R41 + R42) / F4 ≤ 0.94, where R41 is the radius of curvature of the object-side surface of the fourth lens, R42 is the radius of curvature of the image-side surface of the fourth lens, and F4 is the focal length of the fourth lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio of the sum of the radii of curvature of the object-side surface and the radii of curvature of the image-side surface of the fourth lens to the focal length of the fourth lens is beneficial for correcting chromatic aberration and improving the imaging quality of the optical system. Preferably, the zoom lens can further satisfy the following condition: -0.246 ≤ (R41 + R42) / F4 ≤ 0.856, which is even more beneficial for correcting chromatic aberration and improving imaging quality.

[0055] In an exemplary embodiment, the zoom lens can satisfy: 1.63 ≤ (F4-F5) / FG2 ≤ 2.91, where F4 is the focal length of the fourth lens, F5 is the focal length of the fifth lens, and FG2 is the focal length of the zoom lens group. By making the zoom lens satisfy the above condition, the ratio range of the difference between the focal lengths of the fourth and fifth lenses and the focal length of the zoom lens group is controlled, which is beneficial for achieving infrared confocal focus. Preferably, the zoom lens can further satisfy: 1.816 ≤ (F4-F5) / FG2 ≤ 2.644, which is even more conducive to achieving infrared confocal focus.

[0056] In an exemplary embodiment, the zoom lens can satisfy the condition: -2.79 ≤ F5 / Fw ≤ 1.98, where F5 is the focal length of the fifth lens and Fw is the focal length at the wide-angle end of the zoom lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the focal length of the fifth lens and the focal length at the wide-angle end of the zoom lens is beneficial for correcting chromatic aberration and improving image quality. Preferably, the zoom lens can further satisfy the condition: -2.538 ≤ F5 / Fw ≤ 1.804, which is even more beneficial for correcting chromatic aberration and improving image quality.

[0057] In an exemplary embodiment, the zoom lens can satisfy the condition: -1.59 ≤ F5 / FG2 ≤ 0.99, where F5 is the focal length of the fifth lens and FG2 is the focal length of the zoom lens group. By making the zoom lens satisfy the above condition, the ratio range of the focal length of the fifth lens to the focal length of the zoom lens group is controlled, which is beneficial for optimizing aberrations and avoiding defocusing during high and low temperature processes of the system. Preferably, the zoom lens can further satisfy the condition: -1.443 ≤ F5 / FG2 ≤ 0.902, which is even more beneficial for avoiding defocusing during high and low temperature processes of the system.

[0058] In an exemplary embodiment, the zoom lens can satisfy the following conditions: 1.40 ≤ (Nd4 + Nd5) / 2 ≤ 1.82, 49.72 ≤ (Vd4 + Vd5) / 2 ≤ 65.96, where Nd4 is the refractive index of the fourth lens, Nd5 is the refractive index of the fifth lens, Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens. By satisfying the above conditions, controlling the refractive index and Abbe number of the fourth and fifth lenses is beneficial for correcting chromatic aberration, improving image quality, and achieving infrared confocal focusing. Preferably, the zoom lens can further satisfy the following conditions: 1.55 ≤ (Nd4 + Nd5) / 2 ≤ 1.65, 55.25 ≤ (Vd4 + Vd5) / 2 ≤ 59.97, which is even more beneficial for correcting chromatic aberration, improving image quality, and achieving infrared confocal focusing.

[0059] In an exemplary embodiment, the zoom lens can satisfy the following condition: 1.29 ≤ F4 / Fw ≤ 6.18, where F4 is the focal length of the fourth lens and Fw is the focal length at the wide-angle end of the zoom lens. By ensuring the zoom lens satisfies the above condition, the ratio range of the focal length of the fourth lens to the focal length at the wide-angle end of the zoom lens is controlled, which helps to ensure infrared confocal performance and avoid uneven thermal expansion at high temperatures, thus preventing compression between the lens and the lens barrel. Preferably, the zoom lens can further satisfy the following condition: 1.438 ≤ F4 / Fw ≤ 5.621, which is even more conducive to ensuring infrared confocal performance and avoiding uneven thermal expansion at high temperatures, thus preventing compression between the lens and the lens barrel.

[0060] In an exemplary embodiment, the zoom lens can satisfy the following condition: 1.38 ≤ F45 / Fw ≤ 7.62, where F45 is the combined focal length of the fourth and fifth lenses, and Fw is the focal length at the wide-angle end of the zoom lens. By making the zoom lens satisfy the above condition, controlling the ratio range of the combined focal length of the fourth and fifth lenses to the focal length at the telephoto end of the zoom lens is beneficial for correcting chromatic aberration and achieving infrared confocal focus. Preferably, the zoom lens can further satisfy the following condition: 1.539 ≤ F45 / Fw ≤ 6.929, which is even more beneficial for correcting chromatic aberration and achieving infrared confocal focus.

[0061] In an exemplary embodiment, the zoom lens can satisfy the condition: -1.41 ≤ FG1 / FG2 ≤ -0.73, where FG1 is the focal length of the focusing lens group and FG2 is the focal length of the zoom lens group. By making the zoom lens satisfy the above condition, the ratio range of the focal lengths of the focusing lens group and the zoom lens group is controlled, which helps to ensure the temperature stability of the zoom lens in the range of -40 to +80°C. Preferably, the zoom lens can further satisfy the condition: -1.281 ≤ FG1 / FG2 ≤ -0.807, to ensure the temperature stability of the zoom lens in the range of -40 to +80°C.

[0062] In an exemplary embodiment, the zoom lens can satisfy the condition: 1.13 ≤ F2 / FG1 ≤ 9.99, where F2 is the focal length of the second lens and FG1 is the focal length of the focusing lens group. By making the zoom lens satisfy the above condition, the ratio range of the focal length of the second lens and the focal length of the focusing lens group is controlled, which is beneficial for a smooth transition of light trends at large angles and avoids defocusing during high and low temperature processes of the system. Preferably, the zoom lens can further satisfy: 1.261 ≤ F2 / FG1 ≤ 9.078, which is even more beneficial for a smooth transition of light trends at large angles and avoids defocusing during high and low temperature processes of the system.

[0063] In an exemplary embodiment, the zoom lens can satisfy the condition: 0.34 ≤ G2-L / G1-L ≤ 0.96, where G1-L is the displacement of the focusing lens group along the optical axis from the wide-angle end to the telephoto end, and G2-L is the displacement of the zoom lens group along the optical axis from the wide-angle end to the telephoto end. By making the zoom lens satisfy the above condition, controlling the ratio range of the displacement of the focusing lens group along the optical axis from the wide-angle end to the telephoto end and the displacement of the zoom lens group along the optical axis from the wide-angle end to the telephoto end is beneficial for achieving a zoom ratio of 1.1 and satisfying a shorter total length. Preferably, the zoom lens can further satisfy the condition: 0.374 ≤ G2-L / G1-L ≤ 0.877, which is even more beneficial for achieving a zoom ratio of 1.1 and satisfying a shorter total length.

[0064] In an exemplary embodiment, the zoom lens can satisfy the condition: 3.14 ≤ TTL-t / BFL-t ≤ 4.69, where TTL-t is the total optical length at the telephoto end of the zoom lens, and BFL-t is the back focal length at the telephoto end of the zoom lens. By making the zoom lens satisfy the above condition, the ratio range of the total optical length at the telephoto end of the zoom lens to the back focal length at the telephoto end is controlled, which is beneficial for miniaturizing the optical lens. Preferably, the zoom lens can further satisfy: 3.491 ≤ TTL-t / BFL-t ≤ 4.264, which is even more conducive to miniaturizing the optical lens.

[0065] In an exemplary embodiment, the zoom lens can satisfy the condition: 0.24 ≤ IC / TTL-w ≤ 0.31, where IC is the image plane diameter of the zoom lens, and TTL-w is the total optical length at the wide-angle end of the zoom lens. By making the zoom lens satisfy the above condition, controlling the image plane diameter and the total optical length at the wide-angle end of the zoom lens is beneficial for reducing the overall length of the optical system and achieving the requirement of small size. Preferably, the zoom lens can further satisfy the condition: 0.267 ≤ IC / TTL-w ≤ 0.284, which is even more beneficial for reducing the overall length of the optical system and achieving the requirement of small size.

[0066] In an exemplary embodiment, the zoom lens can satisfy: -3.44 ≤ (R21 + R22) / F2 ≤ 1.07, where R21 is the radius of curvature of the object-side surface of the second lens, R22 is the radius of curvature of the image-side surface of the second lens, and F2 is the focal length of the second lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the sum of the radius of curvature of the object-side surface of the second lens and the radius of curvature of the image-side surface of the second lens and the focal length of the second lens, it is beneficial to have a smaller F-number at the wide-angle end and a larger aperture, ensuring sufficient light intake of the system and adapting to various complex environments. Preferably, the zoom lens can further satisfy: -3.125 ≤ (R21 + R22) / F2 ≤ 0.971, which is even more beneficial to have a smaller F-number at the wide-angle end and a larger aperture, ensuring sufficient light intake of the system and adapting to various complex environments.

[0067] In an exemplary embodiment, the zoom lens can satisfy: -3.37 ≤ (R31 + R32) / FG1 ≤ -1.62, where R31 is the radius of curvature of the object-side surface of the third lens, R32 is the radius of curvature of the image-side surface of the third lens, and FG1 is the focal length of the focusing lens group. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the sum of the radii of curvature of the object-side surface of the third lens and the radii of curvature of the image-side surface of the third lens and the focal length of the focusing lens group, it is beneficial to control the direction of light, reduce the field curvature and spherical aberration of the optical system, and improve the image quality of the optical system. Preferably, the zoom lens can further satisfy: -3.064 ≤ (R31 + R32) / FG1 ≤ -1.805, which is even more beneficial to control the direction of light, reduce the field curvature and spherical aberration of the optical system, and improve the image quality of the optical system.

[0068] In an exemplary embodiment, the zoom lens can satisfy: -0.91≤(R12-R21) / F1≤-0.63, where R12 is the radius of curvature of the image-side surface of the first lens, R21 is the radius of curvature of the object-side surface of the second lens, and F1 is the focal length of the first lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the difference between the radius of curvature of the image-side surface of the first lens and the radius of curvature of the object-side surface of the second lens and the focal length of the first lens, it is beneficial to reduce the generation of ghosting and ensure that the system has high imaging quality even at large angles. Preferably, the zoom lens can further satisfy: -0.827≤(R12-R21) / F1≤-0.704, which is even more beneficial to reducing the generation of ghosting and ensuring that the system has high imaging quality even at large angles.

[0069] In an exemplary embodiment, the zoom lens can satisfy: 9.53 ≤ T0 / D0 ≤ 19.54, where T0 is the sum of the center thicknesses of the positive lenses of the zoom lens, and D0 is the center thickness of the last negative lens of the zoom lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the sum of the center thicknesses of the positive lenses and the center thickness of the last negative lens of the zoom lens, it is beneficial to reduce the sensitivity caused by thickness during the manufacturing process, and to correct aberrations such as field curvature, thereby improving the imaging quality of the optical lens. Preferably, the zoom lens can further satisfy: 10.587 ≤ T0 / D0 ≤ 17.760, which is even more beneficial to improving imaging quality.

[0070] In an exemplary embodiment, the zoom lens can satisfy the condition: 1.02 ≤ Ft / Fw ≤ 1.31, where Ft is the focal length at the telephoto end of the zoom lens, and Fw is the focal length at the wide-angle end of the zoom lens. By making the zoom lens satisfy the above condition, the ratio range of the focal length at the wide-angle end of the zoom lens to the focal length at the telephoto end of the zoom lens is controlled, which is beneficial to achieving a zoom ratio of 1.1. Preferably, the zoom lens can further satisfy: 1.132 ≤ Ft / Fw ≤ 1.190, which is even more beneficial to achieving a zoom ratio of 1.1.

[0071] In an exemplary embodiment, the zoom lens can satisfy the following condition: 0.88 ≤ F1 / FG1 ≤ 2.05, where F1 is the focal length of the first lens and FG1 is the focal length of the focusing lens group. By making the zoom lens satisfy the above condition, the ratio of the focal length of the first lens to the focal length of the focusing lens group is controlled, which is beneficial for a smooth transition of light trends at large angles and avoids defocusing during high and low temperature processes of the system. Preferably, the zoom lens can further satisfy the following condition: 0.978 ≤ F1 / FG1 ≤ 1.862, which is even more beneficial for a smooth transition of light trends at large angles and avoids defocusing during high and low temperature processes of the system.

[0072] In an exemplary embodiment, the zoom lens can satisfy: -2.23 ≤ FG1 / Fw ≤ -1.45, where FG1 is the focal length of the focusing lens group, and Fw is the focal length at the wide-angle end of the zoom lens. By making the zoom lens satisfy the above condition, controlling the ratio range of the focal length of the focusing lens group and the focal length at the wide-angle end of the zoom lens is beneficial for converging large-angle incident light rays into the optical system, effectively expanding the field of view of the optical system, so that the half field of view at the wide-angle end satisfies FOV_w ≥ 67°. Preferably, the zoom lens can further satisfy: -2.030 ≤ FG1 / Fw ≤ -1.615, which is more conducive to achieving a large field of view.

[0073] In an exemplary embodiment, the zoom lens can satisfy the following condition: 1.43 ≤ FG2 / Fw ≤ 2.24, where FG2 is the focal length of the zoom lens group and Fw is the focal length at the wide-angle end of the zoom lens. By making the zoom lens satisfy the above condition, the ratio range of the focal length of the zoom lens group and the focal length at the wide-angle end of the zoom lens is controlled, which is beneficial for chromatic aberration correction and achieving infrared confocality. Preferably, the zoom lens can further satisfy the following condition: 1.585 ≤ FG2 / Fw ≤ 2.037, which is even more beneficial for the zoom lens's chromatic aberration correction and infrared confocality performance.

[0074] In an exemplary embodiment, the zoom lens can satisfy the condition: -0.93 ≤ F6 / FG2 ≤ 0.94, where F6 is the focal length of the sixth lens and FG2 is the focal length of the zoom lens group. By making the zoom lens satisfy the above condition, controlling the ratio range of the focal length of the sixth lens and the focal length of the zoom lens group, it is beneficial to allow light to enter the seventh lens with a smaller deflection angle, which can effectively reduce the system tolerance sensitivity. Preferably, the zoom lens can further satisfy: -0.844 ≤ F6 / FG2 ≤ 0.858, which is even more beneficial to reducing tolerance sensitivity.

[0075] In an exemplary embodiment, the zoom lens can satisfy the condition: -2.76 ≤ F7 / FG2 ≤ 1.13, where F7 is the focal length of the seventh lens and FG2 is the focal length of the zoom lens group. By making the zoom lens satisfy the above condition, controlling the ratio range of the focal length of the seventh lens to the focal length of the zoom lens group is beneficial for controlling the light path, shortening the total optical length, making the system structure more compact, and allowing the light to reach the image plane at a smaller angle to match the CRA curve requirements of the subsequent chip. Preferably, the zoom lens can further satisfy the condition: -2.512 ≤ F7 / FG2 ≤ 1.028, which is more conducive to shortening the total length and meeting the CRA curve requirements.

[0076] In an exemplary embodiment, the zoom lens can satisfy the condition: 1.26 ≤ FG2 / Ft ≤ 1.89, where FG2 is the focal length of the zoom lens group and Ft is the focal length at the telephoto end of the zoom lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the focal length of the zoom lens group and the focal length at the telephoto end of the zoom lens is beneficial to reducing changes in chromatic aberration and aberrations during zooming, thereby obtaining high imaging performance. Preferably, the zoom lens can further satisfy: 1.400 ≤ FG2 / Ft ≤ 1.714, which is even more beneficial to reducing changes in chromatic aberration and aberrations throughout the zooming process, thereby obtaining high imaging performance.

[0077] According to the above embodiments of this application, the zoom lens sequentially includes a focusing lens group with negative optical power and a zoom lens group with positive optical power along the optical axis from the object side to the image side. By reasonably allocating the number of lenses, optical power, surface shape and other optical parameters in each lens group, it is possible to achieve at least one of the following: low cost, high resolution, chromatic aberration correction, small size (TTL≤33mm), large aperture (FNO≤1.6), reduced aberration, infrared confocal lens, and resistance to high and low temperatures (can work continuously for a long time under high and low temperature conditions of -40℃ to +80℃).

[0078] However, those skilled in the art should understand that, without departing from the technical solutions claimed in this application, the number of lenses constituting the zoom lens can be changed to obtain the various results and advantages described in this specification.

[0079] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the zoom lens applicable to the above-described embodiments.

[0080] Example 1

[0081] The following is for reference Figures 1 to 2 A zoom lens according to Embodiment 1 of this application is described. Figure 1 This diagram shows a structural schematic of the zoom lens according to Embodiment 1 of this application when it is at the wide-angle end. Figure 2 A schematic diagram of the zoom lens according to Embodiment 1 of this application when it is at the telephoto end is shown.

[0082] like Figure 1 and Figure 2 As shown, the zoom lens, along the optical axis from the object side to the image side, includes, in sequence: a focusing lens group G1 with negative optical power, an aperture stop STO, and a zoom lens group G2 with positive optical power. It should be noted that G1 and G2 are... Figure 1 and Figure 2 Not shown in the image.

[0083] The focusing lens group G1 includes, in sequence, a first lens L1, a second lens L2, and a third lens L3 along the optical axis from the object side to the image side.

[0084] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0085] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0086] The third lens L3 has positive optical power, with its object side S5 being convex and its image side S6 being concave.

[0087] The zoom lens group G2 includes, in sequence from the object side to the image side along the optical axis, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7.

[0088] The fourth lens L4 has positive optical power, and its object side S7 is convex, while its image side S8 is convex.

[0089] The fifth lens L5 has negative optical power, and its object side S8 is concave, as is its image side S9.

[0090] The sixth lens L6 has positive optical power, and its object side S10 is convex, and its image side S11 is convex.

[0091] The seventh lens L7 has negative optical power, with its object side S12 being convex and its image side S13 being concave.

[0092] The zoom lens also includes a filter CG disposed on the image side of the seventh lens L7, which has an object side side S14 and an image side side S15.

[0093] Light from the object passes sequentially through surfaces S1-S15 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S15... Figure 1 and Figure 2 Not shown in the image.

[0094] Table 1 shows the basic parameters of the zoom lens in Example 1, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0095] Table 1

[0096]

[0097]

[0098] In Example 1, the object-side and image-side surfaces of the first lens, second lens, third lens, sixth lens, and seventh lens are all aspherical. The surface shape of the aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0099]

[0100] Where x is the distance vector from the vertex of the aspherical surface at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 below gives the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, A14 and A16 that can be used for each aspherical mirror S1 to S6, S10 to S13 in Example 1.

[0101] Table 2

[0102] Face number k A4 A6 A8 A10 A12 A14 A16 S1 -0.32 -4.61E-03 1.61E-04 -4.29E-06 7.39E-08 -7.45E-10 3.05E-12 0.00E+00 S2 -0.64 -6.51E-03 1.72E-04 -1.85E-05 1.85E-06 -1.91E-07 1.01E-08 -2.46E-10 S3 -2.20 3.14E-03 -6.11E-04 5.39E-05 -3.23E-06 1.31E-07 -2.78E-09 1.61E-11 S4 3.40 1.33E-03 -2.08E-04 2.32E-05 -1.04E-06 1.98E-08 2.02E-10 -4.74E-12 S5 -7.00 1.60E-03 -1.85E-04 2.13E-05 -1.08E-06 9.16E-09 1.34E-09 -3.99E-11 S6 -0.22 5.40E-05 4.08E-06 -1.34E-07 1.71E-07 -2.02E-08 1.59E-09 -5.34E-11 S10 1.09 -1.34E-03 -6.32E-05 -8.31E-08 -9.97E-08 -8.07E-09 3.53E-10 -2.26E-11 S11 -7.17 -3.76E-04 -1.32E-04 1.08E-05 -6.38E-07 1.33E-08 1.90E-10 -9.73E-12 S12 -9.88 -3.75E-05 -4.33E-04 1.89E-05 -5.09E-07 1.68E-08 1.20E-09 -5.97E-11 S13 -5.56 6.27E-05 -3.58E-04 1.97E-05 -1.95E-07 -1.69E-09 -9.84E-11 -2.55E-13

[0103] In Example 1, the distance T0 corresponding to row S6 in Table 1 can be a variable, representing the air gap on the optical axis between the focusing lens group and the zoom lens group when the zoom lens is at the wide-angle and telephoto ends. Similarly, the distance T1 corresponding to row S13 in Table 1 can also be a variable, representing the air gap on the optical axis between the zoom lens group and the filter CG when the zoom lens is at the wide-angle and telephoto ends. In this example, the zoom lens achieves zoom magnification by moving the focusing lens group and the zoom lens group. The values ​​(in mm) of the variables T1 and T2 when the lens is at the wide-angle and telephoto ends are shown in Table 3 below.

[0104] Table 3

[0105]

[0106]

[0107] In this embodiment, the zoom lens has a chip size of 1 / 1.8″; at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.53, and the MTF value of the center field of view at the telephoto end is 0.55.

[0108] Example 2

[0109] The following is for reference Figures 3 to 4 Description of a zoom lens according to Embodiment 2 of this application. Figure 3 This diagram shows a structural schematic of the zoom lens in the wide-angle position according to Embodiment 2 of this application. Figure 4 A schematic diagram of the zoom lens in the telephoto end according to Embodiment 2 of this application is shown.

[0110] like Figure 3 and Figure 4 As shown, the zoom lens, along the optical axis from the object side to the image side, includes, in sequence: a focusing lens group G1 with negative optical power, an aperture stop STO, and a zoom lens group G2 with positive optical power. It should be noted that G1 and G2 are... Figure 3 and Figure 4 Not shown in the image.

[0111] The focusing lens group G1 includes, in sequence, a first lens L1, a second lens L2, and a third lens L3 along the optical axis from the object side to the image side.

[0112] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0113] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0114] The third lens L3 has positive optical power, with its object side S5 being convex and its image side S6 being concave.

[0115] The zoom lens group G2 includes, in sequence from the object side to the image side along the optical axis, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7.

[0116] The fourth lens L4 has positive optical power, and its object side S7 is convex, while its image side S8 is convex.

[0117] The fifth lens L5 has negative optical power, and its object side S8 is concave, as is its image side S9.

[0118] The sixth lens L6 has positive optical power, and its object side S10 is convex, and its image side S11 is convex.

[0119] The seventh lens L7 has negative optical power, with its object side S12 being convex and its image side S13 being concave.

[0120] The zoom lens also includes a filter CG disposed on the image side of the seventh lens L7, which has an object side side S14 and an image side side S15.

[0121] Light from the object passes sequentially through surfaces S1-S15 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S15... Figure 3 and Figure 4 Not shown in the image.

[0122] Table 4 shows the basic parameters of the zoom lens in Example 2, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0123] Table 4

[0124]

[0125]

[0126] In Example 2, the object-side and image-side surfaces of the second, third, fifth, and sixth lenses are all aspherical. The surface shape of the aspherical lens can be defined by, but is not limited to, the formula (1) given in Example 1 above.

[0127] Table 5 below shows the conic coefficients k and higher-order coefficients A4, A6, A8, A10, A12, A14 and A16 that can be used for each aspherical surface S3 to S6, S10 to S13 in Example 2.

[0128] Table 5

[0129] Face number k A4 A6 A8 A10 A12 A14 A16 S3 -7.29 9.00E-04 -7.61E-05 1.71E-06 1.52E-08 -8.14E-10 9.01E-13 0.00E+00 S4 69.98 2.68E-03 -1.13E-05 -1.96E-05 2.47E-06 -2.06E-07 1.07E-08 -2.36E-10 S5 -10.41 2.12E-03 -5.56E-05 5.02E-06 -5.96E-07 1.38E-08 1.83E-09 -7.59E-11 S6 -2.79 -3.09E-04 1.22E-04 -1.24E-05 6.60E-07 -1.52E-08 3.58E-10 -4.83E-12 S10 1.68 -1.17E-03 -5.95E-05 1.80E-06 -1.58E-07 -1.66E-08 1.80E-09 -6.44E-11 S11 -9.76 -1.22E-03 -1.06E-05 5.14E-06 -4.98E-07 1.52E-08 8.14E-11 -8.99E-12 S12 -6.84 2.66E-03 -5.94E-04 2.93E-05 -8.89E-07 5.38E-09 1.24E-09 -3.39E-11 S13 -4.32 3.07E-03 -5.87E-04 2.94E-05 -5.07E-07 2.99E-10 -1.54E-11 3.06E-12

[0130] In Example 2, the distance T1 corresponding to row S6 in Table 4 can be a variable, representing the air gap on the optical axis between the focusing lens group and the zoom lens group when the zoom lens is at the wide-angle and telephoto ends. Similarly, the distance T2 corresponding to row S13 in Table 4 can also be a variable, representing the air gap on the optical axis between the zoom lens group and the filter CG when the zoom lens is at the wide-angle and telephoto ends. In this example, the zoom lens achieves magnification by moving the focusing lens group and the zoom lens group. The values ​​(in mm) of the variables T1 and T2 when the lens is at the wide-angle and telephoto ends are shown in Table 6 below.

[0131] Table 6

[0132] Surface serial number thickness Wide-angle end telephoto end S6 T1 5.409 3.886 S13 T2 6.349 7.062

[0133] In this embodiment, the zoom lens has a chip size of 1 / 1.8″; at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.44, and the MTF value of the center field of view at the telephoto end is 0.40.

[0134] Example 3

[0135] The following is for reference Figures 5 to 6 Description of a zoom lens according to Embodiment 3 of this application. Figure 5 This diagram shows a structural schematic of the zoom lens in the wide-angle position according to Embodiment 3 of this application. Figure 6 A schematic diagram of the zoom lens in the telephoto end according to Embodiment 3 of this application is shown.

[0136] like Figure 5 and Figure 6 As shown, the zoom lens, along the optical axis from the object side to the image side, includes, in sequence: a focusing lens group G1 with negative optical power, an aperture stop STO, and a zoom lens group G2 with positive optical power. It should be noted that G1 and G2 are... Figure 5 and Figure 6 Not shown in the image.

[0137] The focusing lens group G1 includes, in sequence, a first lens L1, a second lens L2, and a third lens L3 along the optical axis from the object side to the image side.

[0138] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0139] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0140] The third lens L3 has positive optical power, with its object side S5 being convex and its image side S6 being concave.

[0141] The zoom lens group G2 includes, in sequence from the object side to the image side along the optical axis, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7.

[0142] The fourth lens L4 has positive optical power, and its object side S7 is convex, while its image side S8 is convex.

[0143] The fifth lens L5 has negative optical power, and its object side S8 is concave, as is its image side S9.

[0144] The sixth lens L6 has positive optical power, and its object side S10 is convex, and its image side S11 is convex.

[0145] The seventh lens L7 has negative optical power, with its object side S12 being convex and its image side S13 being concave.

[0146] The zoom lens also includes a filter CG disposed on the image side of the seventh lens L7, which has an object side side S14 and an image side side S15.

[0147] Light from the object passes sequentially through surfaces S1-S15 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S15... Figure 5 and Figure 6 Not shown in the image.

[0148] Table 7 shows the basic parameters of the zoom lens in Example 3, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0149] Table 7

[0150]

[0151] In Example 3, the object-side and image-side surfaces of the second, third, sixth, and seventh lenses are all aspherical. The surface shape of the aspherical lens can be defined by, but is not limited to, the formula (1) given in Example 1 above.

[0152] Table 8 below gives the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, A14 and A16 that can be used for each aspherical surface S3 to S6, S10 to S13 in Example 3.

[0153] Table 8

[0154] Face number k A4 A6 A8 A10 A12 A14 A16 S3 -7.26 8.98E-04 -7.61E-05 1.70E-06 1.52E-08 -8.12E-10 1.28E-12 0.00E+00 S4 70.00 2.68E-03 -1.15E-05 -1.96E-05 2.47E-06 -2.06E-07 1.07E-08 -2.36E-10 S5 -10.39 2.12E-03 -5.56E-05 5.02E-06 -5.96E-07 1.38E-08 1.83E-09 -7.55E-11 S6 -2.91 -3.12E-04 1.22E-04 -1.24E-05 6.62E-07 -1.51E-08 3.59E-10 -5.43E-12 S10 1.68 -1.17E-03 -5.96E-05 1.80E-06 -1.58E-07 -1.66E-08 1.80E-09 -6.45E-11 S11 -9.77 -1.22E-03 -1.06E-05 5.14E-06 -4.98E-07 1.52E-08 8.07E-11 -9.01E-12 S12 -6.85 2.66E-03 -5.94E-04 2.93E-05 -8.90E-07 5.30E-09 1.24E-09 -3.41E-11 S13 -4.33 3.06E-03 -5.87E-04 2.94E-05 -5.07E-07 2.58E-10 -2.09E-11 2.90E-12

[0155] In Example 3, the distance T1 corresponding to row S6 in Table 7 can be a variable, representing the air gap on the optical axis between the focusing lens group and the zoom lens group when the zoom lens is at the wide-angle and telephoto ends. Similarly, the distance T2 corresponding to row S13 in Table 7 can also be a variable, representing the air gap on the optical axis between the zoom lens group and the filter CG when the zoom lens is at the wide-angle and telephoto ends. In this example, the zoom lens achieves magnification by moving the focusing lens group and the zoom lens group. The values ​​(in mm) of the variables T1 and T2 when the lens is at the wide-angle and telephoto ends are shown in Table 9 below.

[0156] Table 9

[0157] Surface serial number thickness Wide-angle end telephoto end S6 T1 5.698 3.897 S13 T2 6.340 7.042

[0158] In this embodiment, the zoom lens has a chip specification of 1 / 1.8″: at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.45, and the MTF value of the center field of view at the telephoto end is 0.43.

[0159] Example 4

[0160] The following is for reference Figures 7 to 8 The zoom lens according to Embodiment 4 of this application is described. Figure 7 This diagram shows a structural schematic of the zoom lens in the wide-angle position according to Embodiment 4 of this application. Figure 8 A schematic diagram of the zoom lens in the telephoto end according to Embodiment 4 of this application is shown.

[0161] like Figure 7 and Figure 8 As shown, the zoom lens, along the optical axis from the object side to the image side, includes, in sequence: a focusing lens group G1 with negative optical power, an aperture stop STO, and a zoom lens group G2 with positive optical power. It should be noted that G1 and G2 are... Figure 7 and Figure 8 Not shown in the image.

[0162] The focusing lens group G1 includes, in sequence, a first lens L1, a second lens L2, and a third lens L3 along the optical axis from the object side to the image side.

[0163] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0164] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0165] The third lens L3 has negative optical power, with its object side S5 being convex and its image side S6 being concave.

[0166] The zoom lens group G2 includes, in sequence from the object side to the image side along the optical axis, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7.

[0167] The fourth lens L4 has positive optical power, with its object side S7 being convex and its image side S8 being concave.

[0168] The fifth lens L5 has positive optical power, and its object side S9 is convex, and its image side S10 is convex.

[0169] The sixth lens L6 has negative optical power, and its object side S11 is concave, and its image side S12 is concave.

[0170] The seventh lens L7 has positive optical power, and its object side S13 is convex, and its image side S14 is convex.

[0171] The zoom lens also includes a filter CG disposed on the image side of the seventh lens L7, which has an object side side S15 and an image side side S16.

[0172] Light from the object passes sequentially through surfaces S1-S16 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S16 are... Figure 7 and Figure 8 Not shown in the image.

[0173] Table 10 shows the basic parameters of the zoom lens in Example 4, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0174] Table 10

[0175]

[0176] In Example 4, the object-side and image-side surfaces of the first lens, second lens, third lens, fourth lens, sixth lens and seventh lens are all aspherical. The surface shape of the aspherical lens can be limited by, but is not limited to, the formula (1) given in Example 1 above.

[0177] Table 11 below gives the conic coefficient k and higher-order coefficients A4, A6, A8, A10 and A12 that can be used for each aspherical surface S1 to S8, S11 to S14 in Example 4.

[0178] Table 11

[0179]

[0180]

[0181] In Example 4, the distance T1 corresponding to row S6 in Table 10 can be a variable, representing the air gap on the optical axis between the focusing lens group and the zoom lens group when the zoom lens is at the wide-angle and telephoto ends. Similarly, the distance T2 corresponding to row S14 in Table 10 can also be a variable, representing the air gap on the optical axis between the zoom lens group and the filter CG when the zoom lens is at the wide-angle and telephoto ends. In this example, the zoom lens achieves magnification by moving the focusing lens group and the zoom lens group. The values ​​(in mm) of the variables T1 and T2 when the lens is at the wide-angle and telephoto ends are shown in Table 12 below.

[0182] Table 12

[0183] Surface serial number thickness Wide-angle end telephoto end S6 T1 3.896 1.600 S14 T2 6.270 7.134

[0184] In this embodiment, the zoom lens has a chip size of 1 / 1.8″; at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.33, and the MTF value of the center field of view at the telephoto end is 0.42.

[0185] Example 5

[0186] The following is for reference Figures 9 to 10 The zoom lens according to Embodiment 5 of this application is described. Figure 9 This diagram shows a structural schematic of the zoom lens in the wide-angle position according to Embodiment 5 of this application. Figure 10 A schematic diagram of the zoom lens according to Embodiment 5 of this application when it is at the telephoto end is shown.

[0187] like Figure 9 and Figure 10 As shown, the zoom lens, along the optical axis from the object side to the image side, includes, in sequence: a focusing lens group G1 with negative optical power, an aperture stop STO, and a zoom lens group G2 with positive optical power. It should be noted that G1 and G2 are... Figure 9 and Figure 10 Not shown in the image.

[0188] The focusing lens group G1 includes, in sequence, a first lens L1, a second lens L2, and a third lens L3 along the optical axis from the object side to the image side.

[0189] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0190] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0191] The third lens L3 has negative optical power, with its object side S5 being convex and its image side S6 being concave.

[0192] The zoom lens group G2 includes, in sequence from the object side to the image side along the optical axis, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7.

[0193] The fourth lens L4 has positive optical power, with its object side S7 being convex and its image side S8 being concave.

[0194] The fifth lens L5 has positive optical power, and its object side S9 is convex, and its image side S10 is convex.

[0195] The sixth lens L6 has negative optical power, and its object side S11 is concave, and its image side S12 is concave.

[0196] The seventh lens L7 has positive optical power, and its object side S13 is convex, and its image side S14 is convex.

[0197] The zoom lens also includes a filter CG disposed on the image side of the seventh lens L7, which has an object side side S15 and an image side side S16.

[0198] Light from the object passes sequentially through surfaces S1-S16 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S16 are... Figure 9 and Figure 10 Not shown in the image.

[0199] Table 13 shows the basic parameters of the zoom lens of Example 5, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0200] Table 13

[0201]

[0202] In Example 5, the object-side and image-side surfaces of the first lens, second lens, third lens, fourth lens, sixth lens and seventh lens are all aspherical. The surface shape of the aspherical lens can be limited by, but is not limited to, the formula (1) given in Example 1 above.

[0203] Table 14 below gives the conic coefficient k and higher-order coefficients A4, A6, A8, A10 and A12 that can be used for each aspherical surface S1 to S8, S11 to S14 in Example 5.

[0204] Table 14

[0205]

[0206]

[0207] In Example 5, the distance T1 corresponding to row S6 in Table 13 can be a variable, representing the air gap on the optical axis between the focusing lens group and the zoom lens group when the zoom lens is at the wide-angle and telephoto ends. Similarly, the distance T2 corresponding to row S14 in Table 13 can also be a variable, representing the air gap on the optical axis between the zoom lens group and the filter CG when the zoom lens is at the wide-angle and telephoto ends. In this example, the zoom lens achieves magnification by moving the focusing lens group and the zoom lens group. The values ​​(in mm) of the variables T1 and T2 when the lens is at the wide-angle and telephoto ends are shown in Table 15 below.

[0208] Table 15

[0209] Surface serial number thickness Wide-angle end telephoto end S6 T1 3.095 1.230 S14 T2 6.978 7.833

[0210] In this embodiment, the zoom lens has a chip size of 1 / 1.8″; at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.35, and the MTF value of the center field of view at the telephoto end is 0.33.

[0211] In summary, the conditional expressions in Examples 1 to 5 satisfy the relationships shown in Table 16. In Table 16, the parameters Nd4, Vd4, Nd5, and Vd5 have no units, while the units for the remaining parameters are millimeters (mm).

[0212] Table 16

[0213]

[0214]

[0215] This application also provides an imaging device, wherein the electronic photosensitive element may be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS), and the imaging device is equipped with the zoom lens described above.

[0216] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A zoom lens, characterized in that, Along the optical axis from the object side to the image side, in sequence: It has two lens groups in total: a focusing lens group with negative optical power and a zoom lens group with positive optical power. The focusing lens group comprises, sequentially from the object side to the image side along the optical axis: a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power, for a total of three lenses; or There are three lenses in total: a first lens with negative optical power, a second lens with negative optical power, and a third lens with negative optical power. The zoom lens group, along the optical axis from the object side to the image side, sequentially includes: a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power, for a total of four lenses; or There are four lenses in total: a fourth lens with positive optical power, a fifth lens with positive optical power, a sixth lens with negative optical power, and a seventh lens with positive optical power. The zoom lens satisfies the following condition: 3.60≤TTL-w / BFL-w≤5.24; Wherein, TTL-w is the total optical length at the wide-angle end of the zoom lens, and BFL-w is the back focal length at the wide-angle end of the zoom lens.

2. The zoom lens according to claim 1, characterized in that, The object-side surface of the first lens is convex, and the image-side surface is concave. The object-side surface of the second lens is concave, and the image-side surface is either convex or concave. The object-side surface of the third lens is convex, and the image-side surface is concave. The object-side surface of the fourth lens is convex, and the image-side surface is also convex. The object-side surface of the fifth lens is concave, and the image-side surface is also concave. The object-side surface of the sixth lens is convex, and the image-side surface is also convex; and The object-side surface of the seventh lens is convex, and the image-side surface is concave.

3. The zoom lens according to claim 1, characterized in that, The object-side surface of the first lens is convex, and the image-side surface is concave. The object-side surface of the second lens is concave, and the image-side surface is convex. The object-side surface of the third lens is convex, and the image-side surface is concave. The object-side surface of the fourth lens is convex, and the image-side surface is concave. The object-side surface of the fifth lens is convex, and the image-side surface is also convex. The object-side surface of the sixth lens is concave, and the image-side surface is also concave; and The object-side surface of the seventh lens is convex, and the image-side surface is also convex.

4. The zoom lens according to any one of claims 1 to 3, characterized in that, The zoom lens satisfies at least one of the following conditions: -0.27≤(R41+R42) / F4≤0.94; 1.63≤(F4-F5) / FG2≤2.91; -2.79≤F5 / Fw≤1.98; -1.59≤F5 / FG2≤0.99; 1.40≤(Nd4+Nd5) / 2≤1.82; 49.72≤(Vd4+Vd5) / 2≤65.96; Wherein, R41 is the radius of curvature of the object side of the fourth lens, R42 is the radius of curvature of the image side of the fourth lens, F4 is the focal length of the fourth lens, F5 is the focal length of the fifth lens, FG2 is the focal length of the zoom lens group, Fw is the focal length of the wide-angle end of the zoom lens, Nd4 is the refractive index of the fourth lens, Nd5 is the refractive index of the fifth lens, Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens.

5. The zoom lens according to any one of claims 1 to 3, characterized in that, The zoom lens satisfies at least one of the following conditions: 1.29≤F4 / Fw≤6.18; 1.38≤F45 / Fw≤7.62; -1.41≤FG1 / FG2≤-0.73; 1.13≤F2 / FG1≤9.99; 0.34≤G2-L / G1-L≤0.96; Wherein, F4 is the focal length of the fourth lens, Fw is the focal length of the wide-angle end of the zoom lens, F45 is the combined focal length of the fourth and fifth lenses, FG1 is the focal length of the focusing lens group, FG2 is the focal length of the zoom lens group, F2 is the focal length of the second lens, G1-L is the displacement of the focusing lens group from the wide-angle end to the telephoto end along the optical axis, and G2-L is the displacement of the zoom lens group from the wide-angle end to the telephoto end along the optical axis.

6. The zoom lens according to any one of claims 1 to 3, characterized in that, The zoom lens satisfies at least one of the following conditions: 3.14≤TTL-t / BFL-t≤4.69; 0.24≤IC / TTL-w≤0.31; -3.44≤(R21+R22) / F2≤1.07; - 3.37≤(R31+R32) / FG1≤-1.62; -0.91≤(R12-R21) / F1≤-0.63; 9.53≤T0 / D0≤19.54; Wherein, TTL-t is the total optical length at the telephoto end of the zoom lens, BFL-t is the back focal length at the telephoto end of the zoom lens, IC is the image plane diameter of the zoom lens, TTL-w is the total optical length at the wide-angle end of the zoom lens, R21 is the radius of curvature of the object-side surface of the second lens, R22 is the radius of curvature of the image-side surface of the second lens, F2 is the focal length of the second lens, R31 is the radius of curvature of the object-side surface of the third lens, R32 is the radius of curvature of the image-side surface of the third lens, FG1 is the focal length of the focusing lens group, R12 is the radius of curvature of the image-side surface of the first lens, F1 is the focal length of the first lens, T0 is the sum of the center thicknesses of the positive lenses of the zoom lens, and D0 is the center thickness of the last negative lens of the zoom lens.

7. The zoom lens according to any one of claims 1 to 3, characterized in that, The zoom lens satisfies at least one of the following conditions: 1.02≤Ft / Fw≤1.31; 0.88≤F1 / FG1≤2.05; -2.23≤FG1 / Fw≤-1.45; 1.43≤FG2 / Fw≤2.24; -0.93≤F6 / FG2≤0.94; -2.76≤F7 / FG2≤1.13; 1.26≤FG2 / Ft≤1.89; Wherein, Ft is the focal length of the telephoto end of the zoom lens, Fw is the focal length of the wide-angle end of the zoom lens, F1 is the focal length of the first lens, FG1 is the focal length of the focusing lens group, FG2 is the focal length of the zoom lens group, F6 is the focal length of the sixth lens, and F7 is the focal length of the seventh lens.

8. The zoom lens according to any one of claims 1 to 3, characterized in that, The zoom lens satisfies at least one of the following conditions: -0.246≤(R41+R42) / F4≤0.856; 1.816≤(F4-F5) / FG2≤2.644; -2.538≤F5 / Fw≤1.804; -1.443≤F5 / FG2≤0.902; 1. 55≤(Nd4+Nd5) / 2≤1.65; 55.25≤(Vd4+Vd5) / 2≤59.97; 3.998≤TTL-w / BFL-w≤4.762; 3.491≤TTL-t / BFL-t≤4.264; 0.267≤IC / TTL-w≤0.284; -3.125≤(R21+R22) / F2≤0.971; -3.064≤(R31+R3 2) / FG1≤-1.805; -0.827≤(R12-R21) / F1≤-0.704; 10.587≤T0 / D0≤17.760; Wherein, R41 is the radius of curvature of the object-side surface of the fourth lens, R42 is the radius of curvature of the image-side surface of the fourth lens, F4 is the focal length of the fourth lens, F5 is the focal length of the fifth lens, FG2 is the focal length of the zoom lens group, Fw is the focal length at the wide-angle end of the zoom lens, Nd4 is the refractive index of the fourth lens, Nd5 is the refractive index of the fifth lens, Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens; TTL-w is the total optical length at the wide-angle end of the zoom lens, BFL-w is the back focal length at the wide-angle end of the zoom lens; TTL-t is the optical length at the telephoto end of the zoom lens. The total focal length of the zoom lens is defined as follows: BFL-t is the back focal length at the telephoto end of the zoom lens; IC is the image plane diameter of the zoom lens; R21 is the radius of curvature of the object-side surface of the second lens; R22 is the radius of curvature of the image-side surface of the second lens; F2 is the focal length of the second lens; R31 is the radius of curvature of the object-side surface of the third lens; R32 is the radius of curvature of the image-side surface of the third lens; FG1 is the focal length of the focusing lens group; R12 is the radius of curvature of the image-side surface of the first lens; F1 is the focal length of the first lens; T0 is the sum of the center thicknesses of the positive lenses of the zoom lens; and D0 is the center thickness of the last negative lens of the zoom lens.

9. The zoom lens according to any one of claims 1 to 3, characterized in that, The zoom lens satisfies at least one of the following conditions: 1.438≤F4 / Fw≤5.621; 1.539≤F45 / Fw≤6.929; -1.281≤FG1 / FG2≤-0.807; 1.261≤F2 / FG1≤9.078; 0.374≤G2-L / G1-L≤0.877; 1.132≤Ft / Fw≤1.190; 0.978≤F1 / FG1≤1.862; -2.030≤FG1 / Fw≤-1.615;1.585≤FG2 / Fw≤2.037;-0.844≤F6 / FG2≤0.858;-2.512≤F7 / FG2≤1.028;1.400≤FG2 / Ft≤1.714; Wherein, F4 is the focal length of the fourth lens, Fw is the focal length of the wide-angle end of the zoom lens, F45 is the combined focal length of the fourth and fifth lenses, FG1 is the focal length of the focusing lens group, FG2 is the focal length of the zoom lens group, F2 is the focal length of the second lens, G1-L is the displacement of the focusing lens group from the wide-angle end to the telephoto end along the optical axis, G2-L is the displacement of the zoom lens group from the wide-angle end to the telephoto end along the optical axis; Ft is the focal length of the telephoto end of the zoom lens, F1 is the focal length of the first lens, F6 is the focal length of the sixth lens, and F7 is the focal length of the seventh lens.

Images