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 from the object side to the image side 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 focal power; the zoom lens group comprises five or six lenses in sequence from the object side to the image side along the optical axis, i.e. a fourth lens group with positive focal power, a fifth lens with positive or negative focal power, a sixth lens with positive focal power, a seventh lens with negative focal power and an eighth lens with positive focal power; the fourth lens group consists of one or two lenses; when the fourth lens group consists of one lens, the focal power of the lens is positive; when the fourth lens group consists of two lenses, the focal power of the lenses is positive and negative in sequence.

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 the continuous upgrading and development of security monitoring facilities, the requirements of monitoring equipment for the monitoring environment and images have become increasingly higher. The monitoring equipment needs to provide all-weather monitoring images, maintain focus in high and low temperature environments, and ensure that the lens still has high image quality under harsh weather conditions.

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

[0004] 1. It is difficult to properly correct system aberrations, resulting in poor lens image quality;

[0005] 2. The overall optical length is relatively long and the volume is relatively large, resulting in excessively high overall cost and weight of the lens;

[0006] 3. The optical architecture uses multiple glass lenses, which increases the cost of the lens;

[0007] Therefore, given the current state of zoom lens development, high-resolution, miniaturized, and low-cost zoom lenses are one of the current market demands. Summary of the Invention

[0008] This application provides a zoom lens, which, along the optical axis from the object side to the image side, sequentially includes: a focusing lens group with negative optical power and a zoom lens group with positive optical power, totaling two lens groups; the focusing lens group, along the optical axis from the object side to the image side, sequentially includes: a first lens with negative optical power, a second lens with negative optical power, and a third lens with positive optical power, totaling three lenses; the zoom lens group, along the optical axis from the object side to the image side, sequentially includes: a fourth lens group with positive optical power, a fifth lens with either positive or negative optical power, a sixth lens with positive optical power, and a third lens with negative optical power. The lens comprises a seventh lens and an eighth lens with positive optical power, totaling five or six lenses; the fourth lens group consists of one or two lenses; when the fourth lens group consists of one lens, the optical power of the lens is positive; when the fourth lens group consists of two lenses, the optical powers of the lenses are positive and negative in sequence; the zoom lens satisfies the following conditions: 1.07≤F4 / FG2≤1.80, 1.21≤F6 / FG2≤2.26, where F4 is the effective focal length of the fourth lens group, F6 is the effective focal length of the sixth lens, and FG2 is the effective focal length of the zoom lens group.

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

[0010] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: -1.63≤F7 / FG2≤-0.95, 1.17≤F8 / FG2≤1.77, where F7 is the effective focal length of the seventh lens, F8 is the effective focal length of the eighth lens, and FG2 is the effective focal length of the zoom lens group.

[0011] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: 0.87≤(R11+R12) / (R11-R12)≤1.28, 1.25≤D1 / TG1≤1.76, where R11 is the object-side radius of curvature of the first lens, R12 is the image-side radius of curvature of the first lens, D1 is the maximum aperture of the object-side surface of the first lens, and TG1 is the center distance from the object-side surface of the first lens to the image-side surface of the third lens.

[0012] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: -0.48≤(R41+R42) / (R41-R42)≤-0.2, -0.73≤(R61+R62) / (R61-R62)≤0.51, -0.50≤(R71+R72) / (R71-R72)≤-0.06, -0.79≤(R81+R82) / (R81-R 82)≤-0.31, where R41 is the object-side radius of curvature of the fourth lens group, R42 is the image-side radius of curvature of the fourth lens group, R61 is the object-side radius of curvature of the sixth lens, R62 is the image-side radius of curvature of the sixth lens, R71 is the object-side radius of curvature of the seventh lens, R72 is the image-side radius of curvature of the seventh lens, R81 is the object-side radius of curvature of the eighth lens, and R82 is the image-side radius of curvature of the eighth lens.

[0013] According to an exemplary embodiment of this application, the zoom lens satisfies: 73.40≤VD4≤100, where VD4 is the Abbe number of at least one glass lens in the fourth lens group.

[0014] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: 1.19≤F4 / FG2≤1.64, 1.34≤F6 / FG2≤2.06, -1.49≤F7 / FG2≤-1.06, 1.30≤F8 / FG2≤1.61, 0.97≤(R11+R12) / (R11-R12)≤1.16, 1.39≤D1 / TG1≤1.60. -0.44≤(R41+R42) / (R41-R42)≤-0.22, -0.67≤(R61+R62) / (R61-R62)≤0.46, -0.46≤(R71+R72) / (R71-R72)≤-0.07, -0.72≤(R81+R82) / (R81-R82)≤-0.35, 81.56≤VD4≤95.1, where F4 is the fourth perforation. The effective focal lengths of the lens group are: F6 is the effective focal length of the sixth lens, F7 is the effective focal length of the seventh lens, F8 is the effective focal length of the eighth lens, FG2 is the effective focal length of the zoom lens group, R11 is the object-side radius of curvature of the first lens, R12 is the image-side radius of curvature of the first lens, R41 is the object-side radius of curvature of the fourth lens group, R42 is the image-side radius of curvature of the fourth lens group, R61 is the object-side radius of curvature of the sixth lens, R62 is the image-side radius of curvature of the sixth lens, R71 is the object-side radius of curvature of the seventh lens, R72 is the image-side radius of curvature of the seventh lens, R81 is the object-side radius of curvature of the eighth lens, R82 is the image-side radius of curvature of the eighth lens, D1 is the maximum aperture of the object-side surface of the first lens, TG1 is the center distance from the object-side surface of the first lens to the image-side surface of the third lens, and VD4 is the Abbe number of at least one glass lens in the fourth lens group.

[0015] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: 0.08≤(R21+R22) / (R21-R22)≤0.31, 4.96≤(R12-R21) / T12≤8.03, 1.46≤G2_L / G1_L≤2.68, where R12 is the image-side radius of curvature of the first lens, R21 is the object-side radius of curvature of the second lens, R22 is the image-side radius of curvature of the second lens, T12 is the center distance between the image-side and object-side surfaces of the first lens and the second lens, G2_L is the maximum travel of the zoom lens group, and G1_L is the maximum travel of the focusing lens group.

[0016] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: 0.09≤(R21+R22) / (R21-R22)≤0.28, 5.51≤(R12-R21) / T12≤7.30, 1.62≤G2_L / G1_L≤2.44, -0.81≤(R31+R32) / (R31-R32)≤-0.18, 0.20≤H / TTL_ w≤0.25, 1.38≤F2 / FG1≤1.84, -2.80≤F3 / FG1≤-2.10, 4.84≤TTL_w / BFL_w≤5.99, 2.87≤TTL_t / BFL_t≤3.57, -1.83≤FG1 / Fw≤-1.39, 1.88≤FG2 / Fw≤2.37, -1.53≤FG2 / FG1≤-1.15, where R12 is the nth... R21 is the radius of curvature of the image side of the first lens, R22 is the radius of curvature of the object side 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, T12 is the center distance between the image side of the first lens and the object side of the second lens, G2_L is the maximum travel of the zoom lens group, G1_L is the maximum travel of the focusing lens group, H is the full image height of the zoom lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, FG1 is the effective focal length of the focusing lens group, FG2 is the effective focal length of the zoom lens group, Fw is the effective focal length of the zoom lens at the wide-angle end, TTL_w is the total optical length of the zoom lens at the wide-angle end, BFL_w is the optical back focal length of the zoom lens at the wide-angle end, TTL_t is the total optical length of the zoom lens at the telephoto end, and BFL_t is the optical back focal length of the zoom lens at the telephoto end.

[0017] According to an exemplary embodiment of this application, the zoom lens satisfies at least one of the following conditions: -0.73≤(R31+R32) / (R31-R32)≤-0.20, 0.215≤H / TTL_w≤0.23, 1.53≤F2 / FG1≤1.67, -2.54≤F3 / FG1≤-2.33, 5.38≤TTL_w / BFL_w≤5.45, 3.19≤TTL_t / BFL_t≤3.25, -1.66≤FG1 / Fw≤-1.55, 2.09≤FG2 / Fw≤2.16, -1.39≤FG2 / FG1≤-1.28, where R31 is the object-side radius of curvature of the third lens, R32 is the image-side radius of curvature of the third lens, H is the full image height of the zoom lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, FG1 is the effective focal length of the focusing lens group, FG2 is the effective focal length of the zoom lens group, Fw is the effective focal length of the zoom lens at the wide-angle end, TTL_w is the total optical length of the zoom lens at the wide-angle end, BFL_w is the optical back focal length of the zoom lens at the wide-angle end, TTL_t is the total optical length of the zoom lens at the telephoto end, and BFL_t is the optical back focal length of the zoom lens at the telephoto end. Attached Figure Description

[0018] 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:

[0019] 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;

[0020] 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;

[0021] Figure 3 A schematic diagram of the zoom lens at the wide-angle end according to Embodiment 2 of this application is shown;

[0022] Figure 4 A schematic diagram of the zoom lens in the telephoto end according to Embodiment 2 of this application is shown;

[0023] 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;

[0024] Figure 6 A schematic diagram of the zoom lens in the telephoto end according to Embodiment 3 of this application is shown;

[0025] Figure 7A schematic diagram of the zoom lens according to Embodiment 4 of this application when it is at the wide-angle end is shown;

[0026] Figure 8 A schematic diagram of the zoom lens in the telephoto end according to Embodiment 4 of this application is shown;

[0027] 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

[0028] 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

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] In an exemplary embodiment, the focusing lens group of the zoom lens has a negative optical power, and its position along the optical axis is adjustable to compensate for changes 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.

[0037] 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.

[0038] In an exemplary embodiment, the first lens may have negative optical power, and its image-side surface may be concave. Having negative optical power increases the field of view at the wide-angle end of the zoom lens, while also allowing light to enter the optical system as smoothly as possible, which is beneficial for maintaining stable optical performance of the zoom lens under high and low temperature conditions. The concave image-side surface helps to reduce the aperture of the first lens, enabling miniaturization of the zoom lens. In an exemplary embodiment, the object-side surface of the first lens may be convex or concave.

[0039] In an exemplary embodiment, the second lens may have negative optical power, and its object-side surface may be concave, as may its image-side surface. The negative optical power, concave object-side surface, and concave image-side surface of the second lens can effectively control the trajectory of incident light in the optical system, reduce aberrations, improve image quality, and also help achieve stable optical performance of the zoom lens under high and low temperature conditions.

[0040] In an exemplary embodiment, the third lens may have positive optical power, and its object-side surface may be convex, as may its image-side surface. The fact that the third lens has positive optical power and both its object-side and image-side surfaces are convex can effectively control the smooth entry of light into the rear of the optical system, reduce spherical aberration, balance system field curvature, and improve image quality. It also helps to ensure stable optical performance of the zoom lens under high and low temperature conditions.

[0041] In an exemplary embodiment, the zoom lens group of the zoom lens is of positive optical power and its position along the optical axis is adjustable to enable effective focal length switching between the wide-angle end and the telephoto end of the zoom lens.

[0042] In an exemplary embodiment, the zoom lens group includes, in sequence, a fourth lens group, a fifth lens, a sixth lens, a seventh lens, and an eighth lens along the optical axis from the object side to the image side.

[0043] In an exemplary embodiment, the fourth lens group consists of a single lens, namely the fourth lens. The fourth lens may have positive optical power, and its object-side surface may be convex, as may its image-side surface. The fact that the fourth lens has positive optical power and both its object-side and image-side surfaces are convex ensures that the optical power of the lens is evenly distributed between its object-side and image-side surfaces. This helps reduce the tolerance sensitivity of the zoom lens and also helps to achieve stable optical performance of the zoom lens under infrared light conditions.

[0044] In an exemplary embodiment, the fourth lens group has positive optical power and consists of two lenses, namely, fourth sub-lens one and fourth sub-lens two. Fourth sub-lens one can have positive optical power, and its object-side surface can be convex, and its image-side surface can be convex. Fourth sub-lens two can have negative optical power, and its object-side surface can be concave, and its image-side surface can be convex. The fourth lens group has positive optical power, and its object-side and image-side surfaces are both convex, which makes the optical power of the lens group evenly distributed on its object-side and image-side surfaces. This helps to reduce the tolerance sensitivity of the zoom lens and also helps to achieve stable optical performance of the zoom lens in infrared light. Furthermore, the fourth lens group uses a cemented lens, which helps to reduce chromatic aberration and improve the image quality of the zoom lens.

[0045] In an exemplary embodiment, the fifth lens may have positive or negative optical power, and its object-side surface may be convex, while its image-side surface may be concave. Having positive or negative optical power, with a convex object-side surface and a concave image-side surface, helps to reduce the incident and exit angles of light passing through the lens, thereby reducing the overall size of the rear lens group and achieving miniaturization of the zoom lens.

[0046] In an exemplary embodiment, the sixth lens may have positive optical power, and its object-side surface may be convex, as may its image-side surface. Having positive optical power and both the object-side and image-side surfaces of the sixth lens helps to reduce the incident and exit angles of light passing through the lens, thereby reducing the tolerance sensitivity of the zoom lens. It also reduces the CRA (Cost Aspect Ratio) of the zoom lens and allows for a longer back focal length, providing space for optical element installation, avoiding mechanical interference, and ultimately improving production yield and efficiency.

[0047] In an exemplary embodiment, the seventh lens may have negative optical power, and both its object-side and image-side surfaces may be concave. The negative optical power, concave object-side, and concave image-side of the seventh lens help reduce the incident and exit angles of light passing through the lens, thereby reducing the tolerance sensitivity of the zoom lens. Simultaneously, it reduces the CRA (Cost Aspect Ratio) of the zoom lens and allows for a longer back focal length, providing space for optical element installation, avoiding mechanical interference, and ultimately improving production yield and efficiency.

[0048] In an exemplary embodiment, the eighth lens may have positive optical power, and both its object-side and image-side surfaces may be convex. The positive optical power and the convexity of both the object-side and image-side surfaces of the eighth lens allow light to transition smoothly to the image plane, reducing various aberrations and improving the image quality of the zoom lens. It also helps to reduce the incident and exit angles of light passing through the lens, lowering the tolerance sensitivity of the zoom lens, reducing the CRA (Cost Aberration) of the zoom lens, and enabling a long back focal length for the zoom lens. Furthermore, it provides space for the installation of optical components, avoids mechanical interference, and improves production yield and efficiency.

[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 group, or the aperture stop may be located on the object side of the fourth lens group. This 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 total optical length (TTL) of the zoom lens can satisfy: TTL≤30mm, and further, TTL can satisfy: 29.56mm≤TTL≤29.61mm, thus achieving the requirement for a small size of the zoom lens.

[0051] In an exemplary embodiment, any one of the first to eighth lenses can be a glass lens or a plastic lens. A glass lens can effectively suppress the shift in the back focal length of the zoom lens caused by temperature changes, improving the stability of the zoom lens. Simultaneously, a glass lens can effectively avoid image blurring caused by high or low temperature environments, ensuring the normal use of the zoom lens, facilitating heatless zoom lens operation, and better correcting system chromatic aberration, thus improving the zoom lens's resolving power. Plastic lenses can effectively reduce the cost of the zoom lens. As an example, in the first to eighth lenses, the fourth lens group is a glass lens, while the remaining lenses are plastic lenses. This helps reduce the cost of the zoom lens, while also helping to balance the high and low temperature performance of the zoom lens, achieving focus-free operation within the range of -40℃ to +80℃ while maintaining high image quality. Furthermore, using a glass lens helps correct chromatic aberration in the optical system, improves the saturation of lens colors, and further enhances image quality.

[0052] In an exemplary embodiment, this application utilizes a combination of spherical and aspherical lenses, which helps reduce the manufacturing difficulty of the 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, or even all lenses can be aspherical. The characteristic of an aspherical lens is that its curvature changes continuously from the center to the periphery. Unlike spherical lenses, which have a constant curvature from the center to the periphery, aspherical lenses have better radius of curvature characteristics, offering advantages in improving distortion and astigmatism. By using aspherical lenses, aberrations occurring during imaging can be eliminated as much as possible, thereby improving the image quality of the lens.

[0053] In an exemplary embodiment, the zoom lens can satisfy the following condition: 1.07 ≤ F4 / FG2 ≤ 1.80, where F4 is the effective focal length of the fourth lens group and FG2 is the effective focal length of the zoom lens group. By ensuring the zoom lens satisfies the above condition, the ratio range of the effective focal length of the fourth lens group and the effective focal length of the zoom lens group is controlled, which can effectively receive light from the front and back, ensuring a smooth transition, reducing the generation of various aberrations, and thus improving image quality. Preferably, the zoom lens can further satisfy the following condition: 1.19 ≤ F4 / FG2 ≤ 1.64, which is even more conducive to improving image quality.

[0054] In an exemplary embodiment, the zoom lens can satisfy the condition: 1.21 ≤ F6 / FG2 ≤ 2.26, where F6 is the effective focal length of the sixth lens and FG2 is the effective focal length of the zoom lens group. By ensuring the zoom lens satisfies the above condition, the ratio range of the effective focal length of the sixth lens and the effective focal length of the zoom lens group is controlled, which can effectively receive light from the front and back, ensuring a smooth transition, reducing the generation of various aberrations, and thus improving image quality. Preferably, the zoom lens can further satisfy: 1.34 ≤ F6 / FG2 ≤ 2.06, which is even more conducive to improving image quality.

[0055] In an exemplary embodiment, the zoom lens can satisfy the condition: -1.63 ≤ F7 / FG2 ≤ -0.95, where F7 is the effective focal length of the seventh lens and FG2 is the effective focal length of the zoom lens group. By making the zoom lens satisfy the above condition, the ratio range of the effective focal length of the seventh lens and the effective focal length of the zoom lens group is controlled, which can effectively receive the light from the front and back, making the transition smoother, reducing the generation of various aberrations, and thus improving image quality. Preferably, the zoom lens can further satisfy the condition: -1.49 ≤ F7 / FG2 ≤ -1.06, which is even more conducive to improving image quality.

[0056] In an exemplary embodiment, the zoom lens can satisfy the condition: 1.17 ≤ F8 / FG2 ≤ 1.77, where F8 is the effective focal length of the eighth lens and FG2 is the effective focal length of the zoom lens group. By ensuring the zoom lens satisfies the above condition, the ratio range of the effective focal length of the eighth lens and the effective focal length of the zoom lens group is controlled, which effectively receives incoming and outgoing light, ensuring a smooth transition and reducing various aberrations, thus improving image quality. Preferably, the zoom lens can further satisfy the condition: 1.30 ≤ F8 / FG2 ≤ 1.61, which is even more conducive to improving image quality.

[0057] In an exemplary embodiment, the zoom lens can satisfy the following condition: 0.87 ≤ (R11 + R12) / (R11 - R12) ≤ 1.28, where R11 is the object-side radius of curvature of the first lens, and R12 is the image-side radius of curvature of the first lens. By making the zoom lens satisfy the above condition, the ratio range of the sum and difference of the object-side and image-side radii of curvature of the first lens is controlled, making the object-side surface of the first lens relatively flat, which is beneficial to achieving vertical miniaturization of the zoom lens. Preferably, the zoom lens can further satisfy the following condition: 0.97 ≤ (R11 + R12) / (R11 - R12) ≤ 1.16, which is even more beneficial to achieving vertical miniaturization of the zoom lens.

[0058] In an exemplary embodiment, the zoom lens can satisfy the following condition: 1.25 ≤ D1 / TG1 ≤ 1.76, where D1 is the maximum aperture of the object-side surface of the first lens, and TG1 is the center distance from the object-side surface of the first lens to the image-side surface of the third lens. By making the zoom lens satisfy the above condition, the ratio range between the maximum aperture of the object-side surface of the first lens and the center distance from the object-side surface of the first lens to the image-side surface of the third lens is controlled, making the maximum aperture of the first lens smaller, which is beneficial for achieving vertical miniaturization of the zoom lens. Preferably, the zoom lens can further satisfy the following condition: 1.39 ≤ D1 / TG1 ≤ 1.60, which is even more beneficial for achieving vertical miniaturization of the zoom lens.

[0059] In an exemplary embodiment, the zoom lens can satisfy: -0.48 ≤ (R41 + R42) / (R41 - R42) ≤ -0.2, where R41 is the object-side radius of curvature of the fourth lens group, and R42 is the image-side radius of curvature of the fourth lens group. By making the zoom lens satisfy the above condition, the ratio range of the sum and difference of the object-side and image-side radii of curvature of the fourth lens group is controlled, so that the optical power of the lens is evenly distributed on the object-side and image-side, which is beneficial to reducing the tolerance sensitivity of the zoom lens, and at the same time, it is beneficial to achieve stable optical performance of the zoom lens under infrared light. Preferably, the zoom lens can further satisfy: -0.44 ≤ (R41 + R42) / (R41 - R42) ≤ -0.22, which is even more beneficial to reducing the tolerance sensitivity of the zoom lens.

[0060] In an exemplary embodiment, the zoom lens can satisfy the following condition: -0.73 ≤ (R61 + R62) / (R61 - R62) ≤ 0.51, where R61 is the object-side radius of curvature of the sixth lens, and R62 is the image-side radius of curvature of the sixth lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the sum and difference of the object-side and image-side radii of curvature of the sixth lens, it is beneficial to reduce the incident and exit angles of light passing through the lens, thereby reducing the tolerance sensitivity of the zoom lens. Preferably, the zoom lens can further satisfy the following condition: -0.67 ≤ (R61 + R62) / (R61 - R62) ≤ 0.46, which is even more beneficial for reducing the tolerance sensitivity of the zoom lens.

[0061] In an exemplary embodiment, the zoom lens can satisfy the following condition: -0.50 ≤ (R71 + R72) / (R71 - R72) ≤ -0.06, where R71 is the object-side radius of curvature of the seventh lens, and R72 is the image-side radius of curvature of the seventh lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the sum and difference of the object-side and image-side radii of curvature of the seventh lens, it is beneficial to reduce the incident and exit angles of light passing through the lens, thereby reducing the tolerance sensitivity of the zoom lens. Preferably, the zoom lens can further satisfy the following condition: -0.46 ≤ (R71 + R72) / (R71 - R72) ≤ -0.07, which is even more beneficial for reducing the tolerance sensitivity of the zoom lens.

[0062] In an exemplary embodiment, the zoom lens can satisfy: -0.79 ≤ (R81 + R82) / (R81 - R82) ≤ -0.31, where R81 is the object-side radius of curvature of the eighth lens, and R82 is the image-side radius of curvature of the eighth lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the sum and difference of the object-side and image-side radii of curvature of the eighth lens, it is beneficial to reduce the incident and exit angles of light passing through the lens, thereby reducing the tolerance sensitivity of the zoom lens. Preferably, the zoom lens can further satisfy: -0.72 ≤ (R81 + R82) / (R81 - R82) ≤ -0.35, which is even more beneficial for reducing the tolerance sensitivity of the zoom lens.

[0063] In an exemplary embodiment, the zoom lens can satisfy: 73.40 ≤ VD4 ≤ 100, where VD4 is the Abbe number of at least one glass lens in the fourth lens group. By satisfying the above condition, controlling the Abbe number of at least one glass lens in the fourth lens group helps to achieve stable optical performance of the zoom lens under high and low temperatures and infrared light conditions. Preferably, the zoom lens can further satisfy: 81.56 ≤ VD4 ≤ 95.10, which is even more conducive to achieving stable optical performance of the zoom lens under high and low temperatures and infrared light conditions.

[0064] In an exemplary embodiment, the zoom lens can satisfy the following condition: 0.08 ≤ (R21 + R22) / (R21 - R22) ≤ 0.31, where R21 is the object-side radius of curvature of the second lens, and R22 is the image-side radius of curvature of the second lens. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the sum and difference of the object-side and image-side radii of curvature of the second lens is beneficial for controlling the smooth entry of light into the rear of the optical system, reducing the generation of spherical aberration, balancing the field curvature of the system, and improving the imaging quality of the zoom lens. It also helps to ensure stable optical performance of the zoom lens under high and low temperature conditions. Preferably, the zoom lens can further satisfy the following condition: 0.09 ≤ (R21 + R22) / (R21 - R22) ≤ 0.28, which is even more beneficial for improving the imaging quality of the zoom lens.

[0065] In an exemplary embodiment, the zoom lens can satisfy: 4.96 ≤ (R12 - R21) / T12 ≤ 8.03, where R12 is the image-side radius of curvature of the first lens, R21 is the object-side radius of curvature of the second lens, and T12 is the center distance between the image-side and object-side surfaces of the first and second lenses. By satisfying the above condition, the zoom lens can reasonably allocate the image-side radius of curvature of the first lens, the object-side radius of curvature of the second lens, and the center distance between the image-side and object-side surfaces of the first and second lenses, which helps to reduce the ghost image energy level generated between the first and second lenses. Preferably, the zoom lens can further satisfy: 5.51 ≤ (R12 - R21) / T12 ≤ 7.30, which is even more conducive to reducing the ghost image energy level.

[0066] In an exemplary embodiment, the zoom lens can satisfy the condition: 1.46 ≤ G2_L / G1_L ≤ 2.68, where G2_L is the maximum travel of the zoom lens group and G1_L is the maximum travel of the focusing lens group. By making the zoom lens satisfy the above condition, the ratio range of the maximum travel of the zoom lens group to the maximum travel of the focusing lens group can be controlled, thereby reducing the overall optical length of the zoom lens and facilitating its lateral miniaturization. Preferably, the zoom lens can further satisfy the condition: 1.62 ≤ G2_L / G1_L ≤ 2.44, which is even more conducive to achieving lateral miniaturization of the zoom lens.

[0067] In an exemplary embodiment, the zoom lens can satisfy the following condition: -0.81 ≤ (R31 + R32) / (R31 - R32) ≤ -0.18, where R31 is the object-side radius of curvature of the third lens, and R32 is the image-side radius of curvature of the third lens. By satisfying the above condition, the ratio range of the sum and difference of the object-side and image-side radii of curvature of the third lens is controlled, which helps to control the smooth entry of light into the rear of the optical system, reduce the generation of spherical aberration, balance the field curvature of the system, and improve the imaging quality of the zoom lens. It also helps to ensure stable optical performance of the zoom lens under high and low temperature conditions. Preferably, the zoom lens can further satisfy the following condition: -0.73 ≤ (R31 + R32) / (R31 - R32) ≤ -0.20, which is even more conducive to improving the imaging quality of the zoom lens.

[0068] In an exemplary embodiment, the zoom lens can satisfy the condition: 0.20 ≤ H / TTL_w ≤ 0.25, where H is the full-image height of the zoom lens and TTL_w is the total optical length of the zoom lens at the wide-angle end. By making the zoom lens satisfy the above condition, controlling the range of the ratio between the full-image height of the zoom lens and the total optical length of the zoom lens at the wide-angle end is beneficial for achieving lateral miniaturization of the zoom lens. Preferably, the zoom lens can further satisfy the condition: 0.215 ≤ H / TTL_w ≤ 0.23, which is even more beneficial for achieving lateral miniaturization of the zoom lens.

[0069] In an exemplary embodiment, the zoom lens can satisfy the condition: 1.38 ≤ F2 / FG1 ≤ 1.84, where F2 is the effective focal length of the second lens and FG1 is the effective focal length of the focusing lens group. By making the zoom lens satisfy the above condition, the ratio range of the effective focal length of the second lens to the effective focal length of the focusing lens group is controlled, which is beneficial to achieving stable optical performance of the zoom lens under high and low temperature conditions. Preferably, the zoom lens can further satisfy the condition: 1.53 ≤ F2 / FG1 ≤ 1.67, which is even more beneficial to achieving stable optical performance of the zoom lens under high and low temperature conditions.

[0070] In an exemplary embodiment, the zoom lens can satisfy the condition: -2.80 ≤ F3 / FG1 ≤ -2.10, where F3 is the effective focal length of the third lens and FG1 is the effective focal length of the focusing lens group. By making the zoom lens satisfy the above condition, the ratio range of the effective focal length of the third lens to the effective focal length of the focusing lens group is controlled, which is beneficial to achieving stable optical performance of the zoom lens under high and low temperature conditions. Preferably, the zoom lens can further satisfy the condition: -2.54 ≤ F3 / FG1 ≤ -2.33, which is even more beneficial to achieving stable optical performance of the zoom lens under high and low temperature conditions.

[0071] In an exemplary embodiment, the zoom lens can satisfy the following condition: 4.84 ≤ TTL_w / BFL_w ≤ 5.99, where TTL_w is the total optical length of the zoom lens at the wide-angle end, and BFL_w is the optical back focal length of the zoom lens at the wide-angle end. By making the zoom lens satisfy the above condition, the ratio range of the total optical length to the optical back focal length of the zoom lens at the wide-angle end can be controlled, which can reserve space for the installation of optical components, avoid mechanical interference, and help improve production yield and efficiency. Preferably, the zoom lens can further satisfy: 5.38 ≤ TTL_w / BFL_w ≤ 5.45, which is even more conducive to improving production yield and efficiency.

[0072] In an exemplary embodiment, the zoom lens can satisfy the following condition: 2.87 ≤ TTL_t / BFL_t ≤ 3.57, where TTL_t is the total optical length of the zoom lens at the telephoto end, and BFL_t is the optical back focal length of the zoom lens at the telephoto end. By making the zoom lens satisfy the above condition, the ratio range of the total optical length of the zoom lens at the telephoto end to the optical back focal length of the zoom lens at the telephoto end can be controlled, which can reserve space for the installation of optical components, avoid mechanical interference, and help improve production yield and efficiency. Preferably, the zoom lens can further satisfy: 3.19 ≤ TTL_t / BFL_t ≤ 3.25, which is even more conducive to improving production yield and efficiency.

[0073] In an exemplary embodiment, the zoom lens can satisfy the following condition: -1.83 ≤ FG1 / Fw ≤ -1.39, where FG1 is the effective focal length of the focusing lens group, and Fw is the effective focal length of the zoom lens at the wide-angle end. By making the zoom lens satisfy the above condition, the ratio range of the effective focal length of the focusing lens group to the effective focal length of the zoom lens at the wide-angle end is controlled, resulting in a smoother light transition, reducing the generation of various aberrations, and thus improving the image quality of the zoom lens. Preferably, the zoom lens can further satisfy the following condition: -1.66 ≤ FG1 / Fw ≤ -1.55, which is even more conducive to improving the image quality of the zoom lens.

[0074] In an exemplary embodiment, the zoom lens can satisfy the following condition: 1.88 ≤ FG2 / Fw ≤ 2.37, where FG2 is the effective focal length of the zoom lens group, and Fw is the effective focal length of the zoom lens at the wide-angle end. By making the zoom lens satisfy the above condition, the ratio range of the effective focal length of the zoom lens group to the effective focal length of the zoom lens at the wide-angle end is controlled, resulting in a smoother light transition, reducing the generation of various aberrations, and improving the image quality of the zoom lens. Preferably, the zoom lens can further satisfy: 2.09 ≤ FG2 / Fw ≤ 2.16, which is even more conducive to improving the image quality of the zoom lens.

[0075] In an exemplary embodiment, the zoom lens can satisfy the condition: -1.53 ​​≤ FG2 / FG1 ≤ -1.15, where FG1 is the effective focal length of the focusing lens group and FG2 is the effective focal length of the zoom lens group. By satisfying the above condition, the ratio range of the effective focal length of the focusing lens group to the effective focal length of the zoom lens group results in a smoother light transition, reducing the generation of various aberrations and improving the image quality of the zoom lens. Preferably, the zoom lens can further satisfy the condition: -1.39 ≤ FG2 / FG1 ≤ -1.28, which is even more conducive to improving the image quality of the zoom lens.

[0076] The zoom lens according to the above embodiments of this application includes, 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 in sequence. At the same time, by reasonably allocating the number of lenses, optical power, surface shape and other optical parameters of each lens group, it is possible to achieve at least one of the following: low cost, high resolution, chromatic aberration correction, small size (TTL≤30mm), 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℃).

[0077] 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.

[0078] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the zoom lens applicable to the above-described embodiments.

[0079] Example 1

[0080] 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 in the telephoto end according to Embodiment 1 of this application is shown.

[0081] like Figure 1 and Figure 2 As shown, the zoom lens includes, in sequence along the optical axis from the object side to the image side, a focusing lens group G1 with negative optical power and a zoom lens group G2 with positive optical power.

[0082] 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.

[0083] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0084] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0085] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0086] The zoom lens group G2 consists of, along the optical axis from the object side to the image side, the fourth lens group B4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8. The fourth lens group B4 consists of a single lens, namely the fourth lens L4.

[0087] The fourth lens L4 has positive optical power, and its object side S7 (STO) is convex, and its image side S8 is convex.

[0088] The fifth lens L5 has positive optical power, with its object side S9 being convex and its image side S10 being concave.

[0089] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0090] The seventh lens L7 has negative optical power, and its object side S13 is concave, and its image side S14 is concave.

[0091] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0092] The aperture STO is set on the object side of the fourth lens L4.

[0093] The zoom lens also includes a filter CG disposed on the image side of the eighth lens L8, which has an object side side S17 and an image side side S18.

[0094] Light from the object passes sequentially through surfaces S1-S18 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S18... Figure 1 and Figure 2 Not shown in the image.

[0095] 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).

[0096] Table 1

[0097]

[0098]

[0099] In Example 1, the object-side and image-side surfaces of the first lens, second lens, third lens, fifth lens, sixth lens, seventh lens, and eighth lens are all aspherical. The surface shape of the aspherical lens can be limited by, but is not limited to, the following aspherical formula:

[0100]

[0101] 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 and A12 that can be used for each aspherical surface S1 to S6, S9 to S16 in Example 1.

[0102] Table 2

[0103]

[0104]

[0105] In Example 1, the distance D1 corresponding to row S6 in Table 1 can be a variable, representing the air gap on the optical axis between the first lens group and the aperture stop STO when the zoom lens is at the wide-angle and telephoto ends; similarly, the distance D2 corresponding to row S16 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 magnification by moving the focusing lens group and the zoom lens group. The values ​​(in mm) of the variables D1 and D2 when the lens is at the wide-angle and telephoto ends are shown in Table 3 below.

[0106] Table 3

[0107] Surface serial number thickness Wide-angle end middle end Observation Depth S6 D1 5.817 4.152 0.980 S16 D2 0.329 1.024 3.239

[0108] In this embodiment, the zoom lens has a chip size of 1 / 2.7″; 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 0.47.

[0109] Example 2

[0110] 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 4A schematic diagram of the zoom lens in the telephoto end according to Embodiment 2 of this application is shown.

[0111] like Figure 3 and Figure 4 As shown, the zoom lens includes, in sequence along the optical axis from the object side to the image side, a focusing lens group G1 with negative optical power and a zoom lens group G2 with positive optical power.

[0112] 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.

[0113] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0114] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0115] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0116] The zoom lens group G2 consists of, along the optical axis from the object side to the image side, the fourth lens group B4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8. The fourth lens group B4 consists of a single lens, namely the fourth lens L4.

[0117] The fourth lens L4 has positive optical power, and its object side S7 (STO) is convex, and its image side S8 is convex.

[0118] The fifth lens L5 has negative optical power, with its object side S9 being convex and its image side S10 being concave.

[0119] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0120] The seventh lens L7 has negative optical power, and its object side S13 is concave, and its image side S14 is concave.

[0121] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0122] The aperture STO is set on the object side of the fourth lens L4.

[0123] The zoom lens also includes a filter CG disposed on the image side of the eighth lens L8, which has an object side side S17 and an image side side S18.

[0124] Light from the object passes sequentially through surfaces S1-S18 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S18... Figure 3 and Figure 4Not shown in the image.

[0125] 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).

[0126] Table 4

[0127]

[0128] In Embodiment 2, the object-side surface and image-side surface of the first lens, second lens, third lens, fifth lens, sixth lens, seventh lens and eighth 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 Embodiment 1 above.

[0129] Table 5 below gives the conic coefficients k and higher-order coefficients A4, A6, A8, A10 and A12 that can be used for each aspherical surface S1 to S6, S9 to S16 in Example 2.

[0130] Table 5

[0131]

[0132]

[0133] In Example 2, the distance D1 corresponding to row S6 in Table 4 can be a variable, representing the air gap on the optical axis between the first lens group and the aperture stop STO when the zoom lens is at the wide-angle and telephoto ends; similarly, the distance D2 corresponding to row S16 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 D1 and D2 when the lens is at the wide-angle and telephoto ends are shown in Table 6 below.

[0134] Table 6

[0135] Surface serial number thickness Wide-angle end middle end Observation Depth S6 D1 5.571 3.993 0.835 S16 D2 0.329 1.029 3.412

[0136] In this embodiment, the zoom lens has a chip size of 1 / 2.7″; at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.56, and the MTF value of the center field of view at the telephoto end is 0.46.

[0137] Example 3

[0138] 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.

[0139] like Figure 5 and Figure 6 As shown, the zoom lens includes, in sequence along the optical axis from the object side to the image side, a focusing lens group G1 with negative optical power and a zoom lens group G2 with positive optical power.

[0140] 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.

[0141] The first lens L1 has negative optical power, and its object side S1 is concave, and its image side S2 is concave.

[0142] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0143] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0144] The zoom lens group G2 consists of, along the optical axis from the object side to the image side, the fourth lens group B4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8. The fourth lens group B4 consists of a single lens, namely the fourth lens L4.

[0145] The fourth lens L4 has positive optical power, and its object side S7 (STO) is convex, and its image side S8 is convex.

[0146] The fifth lens L5 has negative optical power, with its object side S9 being convex and its image side S10 being concave.

[0147] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0148] The seventh lens L7 has negative optical power, and its object side S13 is concave, and its image side S14 is concave.

[0149] The eighth lens L8 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0150] The aperture STO is set on the object side of the fourth lens L4.

[0151] The zoom lens also includes a filter CG disposed on the image side of the eighth lens L8, which has an object side side S17 and an image side side S18.

[0152] Light from the object passes sequentially through surfaces S1-S18 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S18... Figure 5 and Figure 6 Not shown in the image.

[0153] 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).

[0154] Table 7

[0155]

[0156] In Embodiment 3, the object-side surface and image-side surface of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens and eighth 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 Embodiment 1 above.

[0157] Table 8 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10 and A12 that can be used for each aspherical surface S1 to S16 in Example 3.

[0158] Table 8

[0159]

[0160]

[0161] In Example 3, the distance D1 corresponding to row S6 in Table 7 can be a variable, representing the air gap on the optical axis between the first lens group and the aperture stop STO when the zoom lens is at the wide-angle and telephoto ends; similarly, the distance D2 corresponding to row S14 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 D1 and D2 when the lens is at the wide-angle and telephoto ends are shown in Table 9 below.

[0162] Table 9

[0163] Surface serial number thickness Wide-angle end middle end Observation Depth S6 D1 5.501 3.947 0.760 S16 D2 0.320 1.048 3.616

[0164] In this embodiment, the zoom lens has a chip size of 1 / 2.7″; at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.51, and the MTF value of the center field of view at the telephoto end is 0.44.

[0165] Example 4

[0166] The following is for reference Figures 7 to 8 The zoom lens according to Embodiment 4 of this application is described. Figure 7This 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.

[0167] like Figure 7 and Figure 8 As shown, the zoom lens includes, in sequence along the optical axis from the object side to the image side, a focusing lens group G1 with negative optical power and a zoom lens group G2 with positive optical power.

[0168] 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.

[0169] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0170] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0171] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0172] The zoom lens group G2 includes, along the optical axis from the object side to the image side, the fourth lens group B4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8. The fourth lens group B4 consists of two lenses, namely the fourth sub-lens one L41 and the fourth sub-lens two L42.

[0173] The fourth sub-lens, L41, has positive optical power, with its object-side surface S7 (STO) being convex and its image-side surface S8 being convex.

[0174] The fourth sub-lens, L42, has negative optical power. Its object-side surface S8 is concave, and its image-side surface S9 is convex.

[0175] The fifth lens L5 has negative optical power, with its object side S10 being convex and its image side S11 being concave.

[0176] The sixth lens L6 has positive optical power, and its object side S12 is convex, and its image side S13 is convex.

[0177] The seventh lens L7 has negative optical power, and its object side S14 is concave, and its image side S15 is concave.

[0178] The eighth lens L8 has positive optical power, and its object side S16 is convex, and its image side S17 is convex.

[0179] The aperture stop STO is set on the object side of the fourth sub-lens L41.

[0180] The zoom lens also includes a filter CG disposed on the image side of the eighth lens L8, which has an object side side S18 and an image side side S19.

[0181] Light from the object passes sequentially through surfaces S1-S19 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S19... Figure 7 and Figure 8 Not shown in the image.

[0182] 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).

[0183] Table 10

[0184]

[0185] In Example 4, the object-side surface and image-side surface of the first lens, second lens, third lens, fifth lens, sixth lens, seventh lens and eighth 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.

[0186] 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 S6, S10 to S17 in Example 4.

[0187] Table 11

[0188] Face number k A4 A6 A8 A10 A12 S1 0.000 1.28E-04 -2.14E-05 1.12E-06 -2.77E-08 2.85E-10 S2 0.038 4.29E-04 -1.14E-05 -3.73E-06 3.79E-07 -2.04E-09 S3 -16.807 -2.19E-03 -4.91E-05 7.34E-06 -6.19E-07 -2.40E-08 S4 3.347 -5.41E-04 -7.15E-04 4.18E-05 -7.45E-07 -4.59E-08 S5 7.228 9.08E-04 -4.33E-04 5.43E-06 3.04E-06 -2.05E-07 S6 -30.000 -1.84E-04 1.10E-05 5.93E-06 -3.40E-07 2.10E-08 S10 7.103 -7.32E-04 -1.58E-04 4.35E-06 -2.93E-07 9.71E-09 S11 0.000 3.42E-03 -9.88E-04 9.88E-05 -5.08E-06 1.04E-07 S12 0.000 3.41E-03 -1.00E-03 9.21E-05 -3.91E-06 6.95E-08 S13 -30.000 -1.25E-03 2.72E-04 -4.16E-05 3.02E-06 -6.34E-08 S14 -1.311 2.89E-03 5.96E-04 -9.12E-05 5.22E-06 -1.12E-07 S15 8.487 -3.17E-04 1.18E-03 -1.28E-04 6.53E-06 -1.47E-07 S16 -1.930 -4.89E-03 7.21E-04 -6.34E-05 3.29E-06 -6.49E-08 S17 28.478 -8.11E-04 -3.79E-05 7.68E-06 -7.28E-07 2.89E-08

[0189] In Example 4, the distance D1 corresponding to row S6 in Table 10 can be a variable, representing the air gap on the optical axis between the first lens group and the aperture stop STO when the zoom lens is at the wide-angle and telephoto ends; similarly, the distance D2 corresponding to row S17 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 D1 and D2 when the lens is at the wide-angle and telephoto ends are shown in Table 12 below.

[0190] Table 12

[0191] Surface serial number thickness Wide-angle end middle end Observation Depth S6 D1 5.467 3.927 0.760 S17 D2 0.379 1.100 3.652

[0192] In this embodiment, the zoom lens has a chip size of 1 / 2.7″; at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.54, and the MTF value of the center field of view at the telephoto end is 0.47.

[0193] Example 5

[0194] 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 in the telephoto end according to Embodiment 5 of this application is shown.

[0195] like Figure 9 and Figure 10 As shown, the zoom lens includes, in sequence along the optical axis from the object side to the image side, a focusing lens group G1 with negative optical power and a zoom lens group G2 with positive optical power.

[0196] 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.

[0197] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0198] The second lens L2 has negative optical power, and its object side S3 is concave, as is its image side S4.

[0199] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0200] The zoom lens group G2 includes, along the optical axis from the object side to the image side, the fourth lens group B4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8. The fourth lens group B4 consists of two lenses, namely the fourth sub-lens one L41 and the fourth sub-lens two L42.

[0201] The fourth sub-lens, L41, has positive optical power, with its object-side surface S7 being convex and its image-side surface S8 being convex.

[0202] The fourth sub-lens, L42, has negative optical power. Its object-side surface S8 is concave, and its image-side surface S9 is convex.

[0203] The fifth lens L5 has positive optical power, with its object side S10 being convex and its image side S11 being concave.

[0204] The sixth lens L6 has positive optical power, and its object side S12 is convex, and its image side S13 is convex.

[0205] The seventh lens L7 has negative optical power, and its object side S14 is concave, and its image side S15 is concave.

[0206] The eighth lens L8 has positive optical power, and its object side S16 is convex, and its image side S17 is convex.

[0207] The aperture stop STO is set on the object side of the fourth sub-lens L41.

[0208] The zoom lens also includes a filter CG disposed on the image side of the eighth lens L8, which has an object side side S18 and an image side side S19.

[0209] Light from the object passes sequentially through surfaces S1-S19 and is ultimately imaged onto the imaging plane IMA. It should be noted that surfaces S1 to S19... Figure 9 and Figure 10 Not shown in the image.

[0210] 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).

[0211] Table 13

[0212]

[0213] In Embodiment 5, the object-side surface and image-side surface of the first lens, second lens, third lens, fifth lens, sixth lens, seventh lens and eighth 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 Embodiment 1 above.

[0214] 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 S6, S10 to S17 in Example 5.

[0215] Table 14

[0216] Face number k A4 A6 A8 A10 A12 S1 0.000 -5.41E-04 2.79E-05 -6.20E-07 5.50E-09 8.51E-12 S2 0.116 -9.40E-04 -3.26E-05 -5.12E-06 7.18E-07 -5.23E-08 S3 -14.393 -2.16E-03 -1.04E-04 1.22E-05 -4.50E-07 -3.14E-08 S4 3.590 -1.62E-03 -1.62E-05 -8.36E-05 1.12E-05 -4.82E-07 S5 8.793 -8.63E-04 2.03E-04 -9.77E-05 1.19E-05 -4.78E-07 S6 -30.000 -6.08E-04 3.95E-05 -1.51E-06 3.06E-07 -1.53E-09 S10 1.252 -1.17E-03 -2.08E-04 2.52E-05 -2.19E-06 6.85E-08 S11 0.000 4.02E-04 -2.52E-04 4.47E-05 -3.50E-06 1.01E-07 S12 0.000 3.40E-04 -1.53E-04 2.22E-05 -1.26E-06 2.66E-08 S13 -0.045 -1.83E-04 -2.02E-04 2.89E-05 -1.72E-06 4.11E-08 S14 -0.415 5.49E-03 -2.87E-04 2.09E-05 -1.38E-06 3.76E-08 S15 10.909 2.56E-03 2.99E-04 -2.43E-05 9.42E-07 -2.41E-08 S16 -1.645 -3.26E-03 3.78E-04 -2.50E-05 1.17E-06 -2.35E-08 S17 1.976 -4.90E-04 -6.71E-05 6.43E-06 -4.16E-07 1.29E-08

[0217] In Example 5, the distance D1 corresponding to row S6 in Table 13 can be a variable, representing the air gap on the optical axis between the first lens group and the aperture stop STO when the zoom lens is at the wide-angle and telephoto ends; similarly, the distance D2 corresponding to row S17 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 D1 and D2 when the lens is at the wide-angle and telephoto ends are shown in Table 15 below.

[0218] Table 15

[0219] Surface serial number thickness Wide-angle end middle end Observation Depth S6 D1 5.535 3.957 0.760 S17 D2 0.320 1.074 3.704

[0220] In this embodiment, the zoom lens has a chip size of 1 / 2.7″; at a spatial frequency of 250 lp / mm, the MTF value of the center field of view at the wide-angle end is 0.55, and the MTF value of the center field of view at the telephoto end is 0.49.

[0221] In summary, the conditional expressions in Examples 1 to 5 satisfy the relationships shown in Table 16. In Table 16, parameter Vd4 has no unit, while the units for the other parameters are millimeters (mm).

[0222] Table 16

[0223]

[0224]

[0225] 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.

[0226] 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, in sequence 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. The zoom lens group includes, in sequence along the optical axis from the object side to the image side: a fourth lens group with positive optical power, a fifth lens with positive or negative optical power, a sixth lens with positive optical power, a seventh lens with negative optical power, and an eighth lens with positive optical power, for a total of five or six lenses. The fourth lens group consists of one or two lenses; When the fourth lens group consists of a single lens, the optical power of the lens is positive optical power; When the fourth lens group consists of two lenses, the optical power of the lenses is, in sequence, positive optical power and negative optical power; The zoom lens satisfies the following condition: 1.07≤F4 / FG2≤1.80, 1.21≤F6 / FG2≤2.26, Wherein, F4 is the effective focal length of the fourth lens group, F6 is the effective focal length of the sixth lens, and FG2 is the effective focal length of the zoom lens group.

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

3. The zoom lens according to claim 1 or 2, characterized in that, The zoom lens satisfies at least one of the following conditions: -1.63≤F7 / FG2≤-0.95, 1.17≤F8 / FG2≤1.77, Wherein, F7 is the effective focal length of the seventh lens, F8 is the effective focal length of the eighth lens, and FG2 is the effective focal length of the zoom lens group.

4. The zoom lens according to claim 1 or 2, characterized in that, The zoom lens satisfies at least one of the following conditions: 0.87≤(R11+R12) / (R11-R12)≤1.28, 1.25≤D1 / TG1≤1.76, Wherein, R11 is the radius of curvature of the object side surface of the first lens, R12 is the radius of curvature of the image side surface of the first lens, D1 is the maximum aperture of the object side surface of the first lens, and TG1 is the center distance from the object side surface of the first lens to the image side surface of the third lens.

5. The zoom lens according to claim 1 or 2, characterized in that, The zoom lens satisfies at least one of the following conditions: -0.48≤(R41+R42) / (R41-R42)≤-0.2, -0.73≤(R61+R62) / (R61-R62)≤0.51, -0.50≤(R71+R72) / (R71-R72)≤-0.06, -0.79≤(R81+R82) / (R81-R82)≤-0.31, Wherein, R41 is the object-side radius of curvature of the fourth lens group, R42 is the image-side radius of curvature of the fourth lens group, R61 is the object-side radius of curvature of the sixth lens, R62 is the image-side radius of curvature of the sixth lens, R71 is the object-side radius of curvature of the seventh lens, R72 is the image-side radius of curvature of the seventh lens, R81 is the object-side radius of curvature of the eighth lens, and R82 is the image-side radius of curvature of the eighth lens.

6. The zoom lens according to claim 1 or 2, characterized in that, The zoom lens satisfies: 73.40≤VD4≤100, Wherein, VD4 is the Abbe number of at least one glass lens in the fourth lens group.

7. The zoom lens according to claim 1 or 2, characterized in that, The zoom lens satisfies at least one of the following conditions: 1.19≤F4 / FG2≤1.64, 1.34≤F6 / FG2≤2.06, -1.49≤F7 / FG2≤-1.06, 1.30≤F8 / FG2≤1.61, 0.97≤(R11+R12) / (R11-R12)≤1.16, 1.39≤D1 / TG1≤1.60, -0.44≤(R41+R42) / (R41-R42)≤-0.22, -0.67≤(R61+R62) / (R61-R62)≤0.46, -0.46≤(R71+R72) / (R71-R72)≤-0.07, -0.72≤(R81+R82) / (R81-R82)≤-0.35, 81.56≤VD4≤95.1, Wherein, F4 is the effective focal length of the fourth lens group, F6 is the effective focal length of the sixth lens, F7 is the effective focal length of the seventh lens, F8 is the effective focal length of the eighth lens, FG2 is the effective focal length of the zoom lens group, R11 is the object-side radius of curvature of the first lens, R12 is the image-side radius of curvature of the first lens, R41 is the object-side radius of curvature of the fourth lens group, R42 is the image-side radius of curvature of the fourth lens group, R61 is the object-side radius of curvature of the sixth lens, R62 is the image-side radius of curvature of the sixth lens, R71 is the object-side radius of curvature of the seventh lens, R72 is the image-side radius of curvature of the seventh lens, R81 is the object-side radius of curvature of the eighth lens, R82 is the image-side radius of curvature of the eighth lens, D1 is the maximum aperture of the object-side surface of the first lens, TG1 is the center distance from the object-side surface of the first lens to the image-side surface of the third lens, and VD4 is the Abbe number of at least one glass lens in the fourth lens group.

8. The zoom lens according to claim 1 or 2, characterized in that, The zoom lens satisfies at least one of the following conditions: 0.08≤(R21+R22) / (R21-R22)≤0.31, 4.96≤(R12-R21) / T12≤8.03, 1.46≤G2_L / G1_L≤2.68, Wherein, R12 is the radius of curvature of the image side of the first 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, T12 is the center distance between the image side of the first lens and the object side of the second lens, G2_L is the maximum travel of the zoom lens group, and G1_L is the maximum travel of the focusing lens group.

9. The zoom lens according to claim 1 or 2, characterized in that, The zoom lens satisfies at least one of the following conditions: 0.09≤(R21+R22) / (R21-R22)≤0.28, 5.51≤(R12-R21) / T12≤7.30, 1.62≤G2_L / G1_L≤2.44, -0.81≤(R31+R32) / (R31-R32)≤-0.18, 0.20≤H / TTL_w≤0.25, 1.38≤F2 / FG1≤1.84, -2.80≤F3 / FG1≤-2.10, 4.84≤TTL_w / BFL_w≤5.99, 2.87≤TTL_t / BFL_t≤3.57, -1.83≤FG1 / Fw≤-1.39, 1.88≤FG2 / Fw≤2.37, -1.53≤FG2 / FG1≤-1.15, Wherein, R12 is the image-side radius of curvature of the first lens, R21 is the object-side radius of curvature of the second lens, R22 is the image-side radius of curvature of the second lens, R31 is the object-side radius of curvature of the third lens, R32 is the image-side radius of curvature of the third lens, T12 is the center distance between the image-side and object-side surfaces of the first lens and the second lens, G2_L is the maximum travel of the zoom lens group, G1_L is the maximum travel of the focusing lens group, and H is the zoom lens... The full image height is F2, the effective focal length of the second lens is F3, the effective focal length of the third lens is FG1, the effective focal length of the focusing lens group is FG2, the effective focal length of the zoom lens group is Fw, the effective focal length of the zoom lens at the wide-angle end is TTL_w, the total optical length of the zoom lens at the wide-angle end is BFL_w, the optical back focal length of the zoom lens at the wide-angle end is TTL_t, the total optical length of the zoom lens at the telephoto end is BFL_t, and the optical back focal length of the zoom lens at the telephoto end is TTL_t.

10. The zoom lens according to claim 1 or 2, characterized in that, The zoom lens satisfies at least one of the following conditions: -0.73≤(R31+R32) / (R31-R32)≤-0.20, 0.215≤H / TTL_w≤0.23, 1.53≤F2 / FG1≤1.67, -2.54≤F3 / FG1≤-2.33, 5.38≤TTL_w / BFL_w≤5.45, 3.19≤TTL_t / BFL_t≤3.25, -1.66≤FG1 / Fw≤-1.55, 2.09≤FG2 / Fw≤2.16, -1.39≤FG2 / FG1≤-1.28 Wherein, R31 is the object-side radius of curvature of the third lens, R32 is the image-side radius of curvature of the third lens, H is the full image height of the zoom lens, F2 is the effective focal length of the second lens, F3 is the effective focal length of the third lens, FG1 is the effective focal length of the focusing lens group, FG2 is the effective focal length of the zoom lens group, Fw is the effective focal length of the zoom lens at the wide-angle end, TTL_w is the total optical length of the zoom lens at the wide-angle end, BFL_w is the optical back focal length of the zoom lens at the wide-angle end, TTL_t is the total optical length of the zoom lens at the telephoto end, and BFL_t is the optical back focal length of the zoom lens at the telephoto end.

Images