Optical system and camera module

Abstract

The present application discloses an optical system and an imaging module. The optical system sequentially includes a first element group and a second element group from the object side to the image side along the optical axis. The first element group sequentially includes, from the object side to the image side: a first lens with a positive optical power, a reflecting element, and a second lens with a negative optical power. The reflecting element is used to reflect the light rays emitted from the first lens; the second element group has a positive optical power, and the second element group is movable along the optical axis direction to switch the optical system between a short focal length state and a long focal length state; wherein, the optical system satisfies: 0.39 < DL / DEFL < 0.49, where DL is the movable stroke of the second element group, and DEFL is the change in the effective focal length of the optical system in the long focal length state and its effective focal length in the short focal length state.

Description

Technical Field

[0001] The present application relates to the field of optical devices, and particularly to an optical system and a camera module. Background Art

[0002] With the rapid development of portable electronic devices such as smart phones, telephoto lenses have been widely used due to their advantages of clearly imaging distant objects, having a large magnification ratio, and being able to present the detailed features of distant objects.

[0003] The effective focal length of an optical system is an important criterion for measuring whether the optical system is a telephoto lens. The larger the effective focal length of the optical system, the clearer the distant objects photographed by the optical system. However, the effective focal length of the optical system is proportional to the optical path required by the optical system, that is, the larger the effective focal length of the optical system, the larger the optical path required by the optical system. Therefore, in order to achieve the telephoto characteristics of the optical system, the total length of the existing optical system is usually large, which will seriously limit the application of the optical system in portable electronic devices. Summary of the Invention

[0004] One aspect of the present application provides an optical system, which sequentially includes a first element group and a second element group along the optical axis from the object side to the image side. The first element group sequentially includes, from the object side to the image side: a first lens with positive optical power, a reflecting element, and a second lens with negative optical power. The reflecting element is used to reflect the light rays emitted from the first lens; the second element group has positive optical power, and the second element group is movable along the optical axis direction to switch the optical system between a short focal state and a long focal state; wherein, the optical system satisfies: 0.39 < DL / DEFL < 0.49, where DL is the movable stroke of the second element group, and DEFL is the change in the effective focal length of the optical system in the long focal state and its effective focal length in the short focal state.

[0005] In an exemplary embodiment, the optical system satisfies, in the short focal state: 0 < tan(FOV / 2) < 0.35, where FOV is the maximum field of view angle FOV of the optical system.

[0006] In an exemplary embodiment, the optical system satisfies: 5.2 < D1 / CT1 < 6.0, where D1 is the maximum effective aperture of the first lens, and CT1 is the central thickness of the first lens on the optical axis.

[0007] In an exemplary embodiment, the optical system satisfies: 5.5 < D2 / CT2 < 7.5, where D2 is the maximum effective aperture of the second lens, and CT2 is the central thickness of the second lens on the optical axis.

[0008] In an exemplary embodiment, the optical system satisfies: 3.6 < |f1 / f2| < 5.6, where f1 is the effective focal length of the first lens and f2 is the effective focal length of the second lens.

[0009] In an exemplary embodiment, the optical system satisfies: 1.2 < |FG1 / EFL| < 1.65 in the short focal length state, where FG1 is the effective focal length of the first element group and EFL is the effective focal length of the optical system.

[0010] In an exemplary embodiment, the optical system satisfies: 2.0 < |FG1 / FG2| < 2.5, where FG1 is the effective focal length of the first element group and FG2 is the effective focal length of the second element group.

[0011] In an exemplary embodiment, the optical system satisfies in the short focal length state: 0.05mm -1 <D2x / EPDx / d12 < 0.09mm -1 where D2x is the maximum effective semi-aperture of the first lens in the first direction, EPDx is the entrance pupil diameter of the optical system in the first direction, and d12 is the on-axis distance from the image side of the first lens to the object side of the second lens.

[0012] In an exemplary embodiment, the optical system satisfies in the short focal length state: 0.05mm -1 <D2y / EPDy / d12 < 0.09mm -1 where D2y is the maximum effective semi-aperture of the second lens in the second direction, EPDy is the entrance pupil diameter of the optical system in the second direction, and d12 is the on-axis distance between the image side of the first lens and the object side of the second lens.

[0013] In an exemplary embodiment, the optical system satisfies in the short focal length state: 0.25 < EFL / SL < 0.55, where EFL is the effective focal length of the optical system and SL is the total length of the optical system in the preset principal optical axis direction.

[0014] In an exemplary embodiment, the second element group sequentially includes, from the first element group to the image side, a third lens with a positive optical power, a fourth lens with a negative optical power, a fifth lens with a positive optical power, a sixth lens with a positive or negative optical power, a seventh lens with a positive optical power, and an eighth lens with a negative optical power.

[0015] In an exemplary embodiment, the optical axis includes a first optical axis and a second optical axis at a preset angle, and the second optical axis is the preset principal optical axis; the reflecting element includes a plane mirror, and the plane mirror receives the light rays emitted by the first lens in the direction of the first optical axis and reflects the light rays and emits them in the direction of the second optical axis to the second lens.

[0016] Another aspect of the present application provides a camera module, which includes the above-mentioned optical system and an imaging element for converting an optical image formed by the optical system into an electrical signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings, in which:

[0018] Figure 1 A schematic structural diagram of an optical system according to an embodiment of the present application is shown;

[0019] Figure 2 A schematic structural diagram of an optical system including a lens barrel assembly according to an embodiment of the present application is shown;

[0020] Figure 3 A schematic structural diagram of an optical system in a short-focus state according to Embodiment 1 of the present application is shown;

[0021] Figure 4 A schematic structural diagram of an optical system in a telephoto state according to Embodiment 1 of the present application is shown;

[0022] Figure 5 , Figure 6 as well as Figure 7 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical system of Example 1 of the present application in the short-focus state are respectively shown;

[0023] Figure 8 A schematic structural diagram of an optical system in a short-focus state according to Embodiment 2 of the present application is shown;

[0024] Fig. 9 A schematic structural diagram of an optical system in a telephoto state according to Embodiment 2 of the present application is shown;

[0025] Fig.10 , Fig.11 as well as Fig.12 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical system of Example 2 of the present application in the short-focus state are respectively shown;

[0026] Fig.13 A schematic structural diagram of an optical system in a short-focus state according to Embodiment 3 of the present application is shown;

[0027] Fig.14 A schematic structural diagram of an optical system in a telephoto state according to Embodiment 3 of the present application is shown;

[0028] Fig.15 , Fig.16 as well as Fig.17The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical system of Example 3 of the present application in the short-focus state are respectively shown;

[0029] Fig.18 A schematic structural diagram of an optical system in a short-focus state according to Embodiment 4 of the present application is shown;

[0030] Fig.19 A schematic structural diagram of an optical system in a short-focus state according to Embodiment 4 of the present application is shown;

[0031] Fig. 20 , Fig.21 and Fig. 22 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical system of Example 4 of the present application in the short-focus state are respectively shown;

[0032] Fig.23 A schematic structural diagram of an optical system in a short-focus state according to Embodiment 5 of the present application is shown;

[0033] Fig.24 A schematic structural diagram of an optical system in a telephoto state according to Embodiment 5 of the present application is shown;

[0034] Fig.25 , Fig.26 as well as Fig. 27 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical system of Example 5 of the present application in the short-focus state are respectively shown;

[0035] Fig.28 A schematic structural diagram of an optical system in a short-focus state according to Embodiment 6 of the present application is shown;

[0036] Fig.29 A schematic structural diagram of an optical system in a telephoto state according to Embodiment 6 of the present application is shown;

[0037] Fig.30 , Fig.31 as well as Fig.32 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of the optical system of Example 6 of the present application in the short-focus state are respectively shown;

[0038] Fig.33 A schematic structural diagram of an optical system in a short-focus state according to Embodiment 7 of the present application is shown;

[0039] Fig.34 A schematic diagram showing the structure of an optical system in a telephoto state according to Embodiment 7 of the present application is shown; and

[0040] Fig.35 , Fig.36 as well as Fig.37The axial chromatic aberration curve, astigmatism curve and distortion curve of the optical system of Example 7 of the present application in the short-focus state are respectively shown.

[0041] Illustration Description:

[0042] 100, optical system; E1, first lens; E2, second lens; E3, third lens; E4, fourth lens; E5, fifth lens; E6, sixth lens; E7, seventh lens; E8, eighth lens; E9, filter; P, reflective element; STO, aperture; G1, first element group; G2, second element group; IMA, image plane; 200, lens barrel assembly; 210, first lens barrel; 220, second lens barrel. DETAILED DESCRIPTION

[0043] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same figure numerals refer to the same elements.

[0044] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0045] In the 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 shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0046] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface 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 position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0047] It should also be understood that the terms "including" and / or "having", 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. In addition, when describing the embodiments of the present application, the term "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0048] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0049] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0050] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0051] A periscope camera module is a camera module that can achieve long-distance shooting. For the optical system in the periscope camera module, the optical system can be provided with a reflective element, which increases the effective focal length of the periscope camera module by folding the light path, thereby reducing the total length of the periscope camera module while meeting the long-focal-length shooting requirements, thereby achieving miniaturization of the periscope camera module.

[0052] At present, the effective focal length of the optical system of most periscope camera modules is a fixed value and does not have zoom capability. When a periscope camera module is applied to electronic equipment, in order to meet the shooting requirements at different effective focal lengths, the electronic equipment usually needs to be equipped with multiple camera modules with different effective focal lengths. As electronic equipment gradually develops in the direction of miniaturization, the installation space of the camera module is limited. In addition. When shooting with camera modules with different effective focal lengths, it is difficult to ensure the image quality by switching the camera module. Therefore, it is desired to provide a periscope camera module with a magnification switching function while meeting the miniaturization requirements.

[0053] In order to at least partially solve the above problems or one or more of other potential problems, the present application provides an optical system. Specifically, an optical system with a magnification switching function is provided.

[0054] Figure 1 The schematic diagram of the structure of the optical system according to the embodiment of the present application is shown. The optical system can be applied to a camera module, for example, and the camera module can be a periscope camera module. It should be understood that the optical system can also be applied to other types of camera modules, and the present application does not make specific restrictions on this.

[0055] like Figure 1As shown, the optical system 100 may include a first element group G1 and a second element group G2 in sequence from the object side to the image side along the optical axis. The first element group G1 includes: a first lens E1 with positive optical power, a reflective element P, and a second lens E2 with negative optical power in sequence from the object side to the image side. The reflective element P is used to reflect the light emitted from the first lens E1. The second element group G2 has positive optical power. The second element group G2 is movable along the optical axis to switch the optical system 100 between a short focus state and a long focus state. For example, an image plane IMA may be provided on the image side of the optical system 100.

[0056] When the optical system 100 switches from the short focus state to the long focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis (e.g., optical axis II) toward the first element group G1, and the axial distance between the first element group G1 and the second element group G2 decreases, and the axial distance between the second element group G2 and the image plane IMA of the optical system 100 increases, until the second element group G2 moves to the first variable point, so that a clear image can be formed on the image plane IMA. The optical system 100 has a large effective focal length and magnification in the long focus state.

[0057] When the optical system 100 switches from the telephoto state to the short-focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis (e.g., optical axis II) toward the image plane IMA, and the axial distance between the first element group G1 and the second element group G2 increases, and the axial distance between the second element group G2 and the image plane IMA of the optical system 100 decreases, until the second element group G2 moves to the second variable point, so that a clear image can be formed on the image plane IMA. The optical system 100 has a smaller effective focal length and magnification in the short-focus state.

[0058] It should be noted that the telephoto state and short focal state of the optical system 100 are relative concepts and do not represent a specific value of the effective focal length of the optical system 100. The effective focal length of the optical system 100 in the telephoto state is greater than the effective focal length of the optical system 100 in the short focal state.

[0059] The first element group G1 is used to realize the optical path turning, which can effectively shorten the total length of the optical system 100 and meet the requirements of miniaturization. The first lens E1 with positive optical power converges the light, so that the light is still in a converged state after being reflected by the reflective element P, and the number of light entering the second lens E2 is increased, thereby increasing the effective aperture of the optical system 100, improving the imaging quality of the optical system 100, and can also reduce the optical effective aperture of the lens in the second element group G2, reduce the shoulder height of the second element group G2, and thus reduce the total height of the optical system 100. The second lens E2 with negative optical power can expand the light, and can further reduce the aperture of the lens in the rear element group (for example, the second element group G2), thereby reducing the shoulder height of the rear element group.

[0060] The optical power of each lens and the number of lenses in the second element group G2 are reasonably allocated, and by changing the on-axis distance between the first element group G1 and the second element group G2, when the second element group G2 moves to the first focal point, the optical system 100 is in a telephoto state; when the second element group G2 moves to the second focal point, the optical system 100 is in a short focal state, thereby realizing the switching of the effective focal length and magnification of the optical system 100.

[0061] In an exemplary embodiment, the first lens E1 has a positive optical power and can be used to converge light. By making the first lens E1 have a convergence effect on light, the light can be kept in a convergence state after being reflected by the reflective element P, and the number of light rays entering the second lens E2 is increased, and the effective aperture (i.e., the amount of light entering) of the optical system 100 is increased without changing the physical aperture of the aperture STO. In other words, under the same light conditions, the optical system 100 can capture more light, thereby improving the brightness of the image formed by the optical system 100. For example, in a dark environment, the optical system 100 with a large aperture can capture more light, which is particularly important for improving the imaging quality of the optical system 100 and the camera module including the optical system 100 in a dark environment.

[0062] In an exemplary embodiment, the second lens E2 may have a negative optical power and may expand the light reflected by the reflective element P. By making the second lens E2 expand the light, on the one hand, under the convergence effect of the first lens E1 on the light, the aperture of the lens in the rear element group can be further reduced, thereby reducing the shoulder height of the rear element group. In addition, when the reflective element P is driven to achieve optical image stabilization, the movement of the reflective element P has little effect on the position of the light on the second element group G2, and the MTF drop value of the optical system 100 is small, that is, the anti-shake sensitivity is low; on the other hand, the first lens E1 can have a smaller aperture, which helps to reduce the total length and total width of the optical system 100. For example, by reasonably allocating the optical power of the first lens E1 and the second lens E2, the shoulder height and anti-shake sensitivity of the optical system 100 can be balanced with the total length and total width, so that the optical system 100 has better anti-shake performance while ensuring that the optical system 100 has a small size.

[0063] As an example, the first lens E1 may be a biconvex lens. For example, the object-side surface of the first lens E1 may be a convex surface in the paraxial region, and the image-side surface of the first lens E1 may be a convex surface in the paraxial region.

[0064] As an example, the first lens E1 may be a meniscus lens convex toward the object side. For example, the object-side surface of the first lens E1 may be a convex surface in the paraxial region, and the image-side surface may be a concave surface in the paraxial region. As an example, the second lens E2 may be a biconcave lens. For example, the object-side surface of the second lens E2 may be a convex surface or a concave surface in the paraxial region, and the image-side surface may be a concave surface in the paraxial region. It should be noted that when the object-side surface of the second lens E2 is a convex surface in the paraxial region, the object-side surface of the second lens E2 may have an inflection point, so that the object-side surface of the second lens E2 is generally concave as a whole.

[0065] As an example, the second lens E2 may be a meniscus lens convex toward the image side. For example, the object side surface of the second lens E2 may be a concave surface in the paraxial region, and the image side surface may be a convex surface in the paraxial region.

[0066] It should be noted that the object-side surface of the first lens E1 or the second lens E2 is a convex surface, which means that the surface is convex toward the object side, and the object-side surface of the first lens E1 or the second lens E2 is a concave surface, which means that the surface is concave toward the object side. The image-side surface of the first lens E1 or the second lens E2 is a convex surface, which means that the surface is convex toward the image side, and the image-side surface of the first lens E1 or the second lens E2 is a concave surface, which means that the surface is concave toward the image side.

[0067] In an exemplary embodiment, the reflective element P is arranged at any desired angle to bend the optical path. The reflective element P may be arranged to deflect the incident optical path by a preset degree (for example, but not limited to 90°), for example, so that the incident optical path is transformed from propagating along the first optical axis (abbreviated as optical axis I) to propagating along the second optical axis (abbreviated as optical axis II). It should be understood that the optical axis herein may include the first optical axis (i.e., optical axis I) and the second optical axis (i.e., optical axis II) at a preset angle. The second optical axis (i.e., optical axis II) may be a preset main optical axis.

[0068] In an exemplary embodiment, the reflective element P may be disposed between the first lens E1 and the second lens E2. That is, the first lens E1 may be located on the optical axis I and disposed between the object side and the reflective element P, and the second lens E2 may be located on the optical axis II and disposed between the reflective element P and the second element group G2. The reflective element P may receive the light emitted from the first lens E1 along the direction of the optical axis I, and reflect the light and emit it to the second lens E2 along the direction of the optical axis II. The optical axis I and the optical axis II are at a preset angle, for example but not limited to, the optical axis I is perpendicular to the optical axis II.

[0069] In an exemplary embodiment, the reflective element P may be a plane reflector, and the plane reflector may have a reflective surface. The light emitted from the first lens E1 in the direction of the optical axis I is totally reflected by the reflective surface of the reflective element P and is emitted to the second lens E2 in the direction of the optical axis II. The reflective surface of the reflective element P passes through the intersection of the optical axis I and the optical axis II, that is, the reflective surface of the reflective element P is located on both the optical axis I and the optical axis II. By adopting a plane reflector of smaller weight and size as the reflective element, the weight and size of the first element group G1 can be constrained within a certain range, the weight and size of the optical system 100 can be reduced as much as possible, and the driving burden of the reflective element P can be reduced.

[0070] It should be understood that the plane reflector only has a reflective surface, and its position facing the light incident side and the light exiting side is empty. When the first lens E1 is set, the first lens E1 can be made closer to the plane reflector, thereby reducing the height space occupied by the first lens E1 and the reflective element P, thereby reducing the overall height of the optical system 100.

[0071] In an exemplary embodiment, there may be a spacing distance between the first lens E1 and the reflective element P. There may be a spacing distance between the second lens E2 and the reflective element P. By providing a spacing between the first lens E1, the second lens E2 and the reflective element P, multiple options can be provided for the surface design of the side surface of the first lens E1 and the second lens E2 close to the reflective element P, thereby improving the flexibility of the surface design of the side surface of the first lens E1 and the second lens E2 close to the reflective element P.

[0072] It should be understood that the spacing distance between the first lens E1 and the reflective element P means that a surface of one side of the first lens E1 close to the reflective element P has a certain gap with at least a portion of the reflective element P, rather than the first lens E1 is completely non-contacting with the reflective element P. Similarly, the spacing distance between the second lens E2 and the reflective element P means that a surface of one side of the second lens E2 close to the reflective element P has a certain gap with at least a portion of the reflective element P, rather than the second lens E2 is completely non-contacting with the reflective element P.

[0073] In an exemplary embodiment, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 in the second element group G2 may be located on the optical axis II. The third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 may be arranged in order from the second lens E2 to the image side along the optical axis II.

[0074] In an exemplary embodiment, the effective focal length FG2 of the second element group G2 may be greater than 0. For example, the combined focal length of each lens in the second element group G2 may be greater than 0. In other words, the second element group G2 may have positive optical power.

[0075] In an exemplary embodiment, the third lens E3 has positive power, the fourth lens E4 has negative power, the fifth lens E5 has positive power, the sixth lens E6 has positive power or negative power, the seventh lens E7 has positive power, and the eighth lens E8 has negative power.

[0076] As an example, the object-side surface of the third lens E3 may be a convex surface in the paraxial region, and the image-side surface may be a convex surface in the paraxial region.

[0077] As an example, the object-side surface of the fourth lens E4 may be a convex surface in the paraxial region, and the image-side surface may be a concave surface in the paraxial region.

[0078] As an example, the object-side surface of the fifth lens E5 may be a convex surface in the paraxial region, and the image-side surface may be a convex surface or a concave surface in the paraxial region.

[0079] As an example, the object-side surface of the sixth lens E6 may be a concave surface in the paraxial region, and the image-side surface may be a convex surface in the paraxial region.

[0080] As an example, the object-side surface of the seventh lens E7 may be a convex surface in the paraxial region, and the image-side surface may be a convex surface in the paraxial region.

[0081] As an example, the object-side surface of the eighth lens E8 may be a concave surface in the paraxial region, and the image-side surface may be a concave surface in the paraxial region.

[0082] It should be noted that the object side surface of any lens from the third lens E3 to the eighth lens E8 being a convex surface means that the surface is convex toward the object side, and the object side surface of any lens from the third lens E3 to the eighth lens E8 being a concave surface means that the surface is concave toward the object side. The image side surface of any lens from the third lens E3 to the eighth lens E8 being a convex surface means that the surface is convex toward the image side, and the image side surface of any lens from the third lens E3 to the eighth lens E8 being a concave surface means that the surface is concave toward the image side.

[0083] It should be understood that the number of lenses included in the second element group G2 being six is ​​only an example, and the present application does not impose any specific limitation on the number of lenses included in the second element group G2.

[0084] In an exemplary embodiment, the optical system 100 may further include a filter E9. The filter E9 may be disposed on the image side of the second element group G2 and may be used to filter the light emitted from the second element group G2. The filter E9 may be, for example, an infrared filter.

[0085] In an exemplary embodiment, the optical system 100 may further include a stop STO. The stop STO may be disposed, for example, between the second lens E2 and the third lens E3.

[0086] In an exemplary embodiment, at least one surface of the first lens E1 to the eighth lens E8 is an aspherical surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After using an aspherical lens, the aberration occurring during imaging can be eliminated as much as possible, thereby improving the imaging quality.

[0087] Figure 2 A schematic structural diagram of an optical system including a lens barrel assembly according to an embodiment of the present application is shown.

[0088] In an exemplary embodiment, if Figure 2 As shown, the optical system 100 may also include a lens barrel assembly 200. The lens barrel assembly 200 may include a first lens barrel 210 and a second lens barrel 220. The first element group G1 may be fixed in the first lens barrel 210. The second element group G2 may be fixed in the second lens barrel 220. The first lens barrel 210 may have a first opening located at the light incident side and a second opening located at the light exit side, the first lens E1 may be arranged in the first opening, the second lens E2 may be arranged in the second opening, and the reflective element P may be arranged between the first opening and the second opening. The inner diameter of the first opening may be greater than the inner diameter of the second opening, or the inner diameter of the first opening may be equal to the inner diameter of the second opening. The inner diameters of the parts corresponding to different lenses in the second lens barrel 220 are different.

[0089] During the switching process between the short - focal - length state and the long - focal - length state of the optical system 100, the position of the first lens barrel 210 and the first element group G1 disposed therein is fixed. The second lens barrel 220 drives the second element group G2 disposed therein to move along the optical axis II.

[0090] As an example, during the switching process of the optical system 100 from the short - focal - length state to the long - focal - length state, the position of the first lens barrel 210 and the first element group G1 disposed therein is fixed. The second lens barrel 220 drives the second element group G2 disposed therein to move along the optical axis II towards the first lens barrel 210. As another example, during the switching process of the optical system 100 from the short - focal - length state to the long - focal - length state, the position of the first lens barrel 210 and the first element group G1 disposed therein is fixed. The second lens barrel 220 drives the second element group G2 disposed therein to move along the optical axis II towards the image plane IMA.

[0091] In an exemplary embodiment, during the process of the optical system 100 switching between the short - focal - length state and the long - focal - length state, the second lens barrel 220 and the second element group G2 disposed therein can be driven by a first motor (not shown) to move along the optical axis II.

[0092] In an exemplary embodiment, the optical system 100 can satisfy: 0.39 < DL / DEFL < 0.49, where DL is the movable stroke of the second element group G2, and DEFL is the change in the effective focal length of the optical system 100 in the long - focal - length state minus the effective focal length of the optical system 100 in the short - focal - length state. For example, DL can be the moving distance of the second element group G2 along the optical axis II during the switching process of the optical system 100 between the short - focal - length state and the long - focal - length state. By reasonably configuring the ratio of the movable stroke of the second element group G2 to the change in the effective focal length of the optical system 100 in different states, with the limited moving distance of the second element group G2, the optical system 100 can switch between the short - focal - length state and the long - focal - length state, and ensure that the optical system 100 achieves optimal focusing in both the short - focal - length state and the long - focal - length state, guaranteeing the imaging quality in different states.

[0093] In an exemplary embodiment, the optical system 100 in the short - focal - length state can satisfy: 0 < tan(FOV / 2) < 0.35, where FOV is the maximum field - of - view angle of the optical system 100. By reasonably configuring the tangent value of half of the maximum field - of - view angle of the optical system 100, the optical system 100 can have a smaller field - of - view angle, which is beneficial for the optical system 100 to image distant objects, thus ensuring good imaging quality of the optical system 100 at a long distance.

[0094] In an exemplary embodiment, the optical system 100 may satisfy: 5.2 < D1 / CT1 < 6.0, where D1 is the maximum effective semi-aperture of the first lens E1, and CT1 is the central thickness of the first lens E1 on the optical axis (e.g., the optical axis I). D1 may be, for example, the maximum value among the effective semi-apertures of the object side surface of the first lens E1 in the first direction, the effective semi-aperture of the object side surface of the first lens E1 in the third direction, the effective semi-aperture of the image side surface of the first lens E1 in one direction, and the effective semi-aperture of the image side surface of the first lens E1 in the third direction. Among them, the first direction may be, for example, a direction perpendicular to the plane formed by the optical axis I and the optical axis II. The third direction may be, for example, a direction parallel to the optical axis II. By reasonably configuring the ratio of the maximum effective semi-aperture D1 of the first lens E1 to the central thickness CT1 of the first lens E1, while meeting the processability requirements of the first lens E1, the total height of the optical system 100 can be reduced, the structure of the optical system 100 can be made more compact, thereby reducing the volume of the optical system 100, and it is also beneficial to increase the aperture of the optical system 100.

[0095] In an exemplary embodiment, the optical system 100 may satisfy: 5.5 < D2 / CT2 < 7.5, where D2 is the maximum effective semi-aperture of the second lens E2, and CT2 is the central thickness of the second lens E2 on the optical axis (e.g., the optical axis II). D2 may be, for example, the maximum value among the effective semi-apertures of the object side surface of the second lens E2 in the first direction, the effective semi-aperture of the object side surface of the first lens E1 in the second direction, the effective semi-aperture of the image side surface of the second lens E2 in the first direction, and the effective semi-aperture of the second lens E2 in the second direction. Among them, the first direction may be, for example, a direction perpendicular to the plane formed by the optical axis I and the optical axis II. The second direction may be, for example, a direction parallel to the optical axis I. By reasonably configuring the ratio of the maximum effective semi-aperture of the second lens E2 to the central thickness of the second lens E2, while meeting the processability requirements of the second lens E2, the total length of the optical system 100 can be reduced, and the structure of the optical system 100 can be made more compact, thereby reducing the volume of the optical system 100.

[0096] In an exemplary embodiment, the optical system 100 may satisfy: 3.6 < |f1 / f2| < 5.6, where f1 is the effective focal length of the first lens E1, and f2 is the effective focal length of the second lens E2. By reasonably configuring the ratio of the effective focal lengths of the first lens E1 and the second lens E2, the first lens E1 can have a strong light converging ability, a strong effect on expanding the aperture, and ensure that the light is still in a converging state after being reflected by the reflecting element P, which is beneficial to reducing the aperture of the second lens E2, and further reducing the aperture of the lenses in the rear-end element group (e.g., the second element group G2), and reducing the shoulder height of the rear-end element group.

[0097] In an exemplary embodiment, the optical system 100 can satisfy the following in a short-focus state: 1.5<|FG1 / EFL|<1.8, where FG1 is the effective focal length of the first element group G1, and EFL is the effective focal length of the optical system 100. Reasonable configuration of the ratio of the effective focal length of the first element group G1 to the effective focal length of the optical system 100 can enable the first element group G1 to have a certain convergence capability, thereby converging the light and helping to reduce the shoulder height of the rear element group.

[0098] In an exemplary embodiment, the optical system 100 may satisfy: 2.0<|FG1 / FG2|<2.5, where FG1 is the effective focal length of the first element group G1, and FG2 is the effective focal length of the second element group G2. By properly configuring the ratio of the effective focal length of the first element group G1 to the effective focal length of the second element group G2, the optical system 100 can switch between the short focus state and the long focus state under the condition of the limited moving distance of the second element group G2, and ensure that the optical system 100 achieves the best focus in both the short focus state and the long focus state, thereby ensuring the imaging quality in different states.

[0099] In an exemplary embodiment, at least one of the second lens E2 to the eighth lens E8 may be a trimmed lens. The semi-aperture of the trimmed lens in the first direction and the second direction may be different. The first lens E1 may also be a trimmed lens, and the semi-aperture of the trimmed lens in the first direction and the third direction may be different. Among them, the first direction may be, for example, a direction perpendicular to the plane formed by the optical axis I and the optical axis II. The second direction may be, for example, a direction parallel to the optical axis I. The third direction may be, for example, a direction parallel to the optical axis II. By providing a trimmed lens, the total width of the rear end element group (for example, the second element group G2) in the first direction or the shoulder height of the rear end element group can be further reduced, thereby reducing the total width of the optical system 100 in the first direction or the total height of the optical system 100.

[0100] In an exemplary embodiment, the optical system 100 can meet the following requirements in a short focal state: 0.05 mm -1 <D2x / EPDx / d12<0.09mm -1, where D2x is the maximum effective semi-aperture of the second lens E2 in the first direction, EPDx is the entrance pupil diameter of the optical system 100 in the first direction, and d12 is the on-axis distance from the image side of the first lens E1 to the object side of the second lens E2. For example, D2x can be the maximum value between the effective semi-aperture of the object side of the second lens E2 in the first direction and the effective semi-aperture of the image side of the second lens E2 in the first direction. By constraining the above conditional expression, while the optical system 100 meets the large aperture requirement, the effective aperture of the second lens E2 can be constrained within a reasonable range, which is beneficial to reducing the total width of the second element group G2 in the first direction, thereby reducing the total width of the optical system 100 in the first direction.

[0101] In an exemplary embodiment, the optical system 100 can satisfy: 0.05mm -1 <D2y / EPDy / d12 < 0.09mm -1 , where D2y is the maximum effective semi-aperture of the second lens E2 in the second direction, EPDy is the entrance pupil diameter of the optical system 100 in the second direction, and d12 is the on-axis distance from the image side of the first lens E1 to the object side of the second lens E2. For example, D2y can be the maximum value between the effective semi-aperture of the object side of the second lens E2 in the second direction and the effective semi-aperture of the image side of the second lens E2 in the second direction. The second direction can be, for example, a direction parallel to the optical axis I. By constraining the above conditional expression, while the optical system 100 meets the large aperture requirement, the effective aperture of the second lens E2 can be constrained within a reasonable range, which is beneficial to reducing the shoulder height of the second element group G2, thereby reducing the total height of the optical system 100.

[0102] In an exemplary embodiment, the optical system 100 can satisfy: 0.25 < EFL / SL < 0.55 in the short focal length state, where EFL is the effective focal length of the optical system 100 and SL is the total length of the optical system 100 in the preset principal optical axis direction (for example, the optical axis II). By reasonably configuring the ratio of the effective focal length of the optical system 100 to the total length of the optical system 100, while the optical system 100 has long focal length characteristics, the total length of the optical system 100 can be shortened.

[0103] In the present application, SL represents the total length of the optical system 100 in the direction of the preset principal optical axis (e.g., optical axis II), specifically, SL is the distance between the first lens E1 and the image plane IMA on the optical axis II. GH represents the shoulder height of the rear element group (e.g., the second element group G2), specifically, GH is determined by the maximum aperture of each lens in the second element group G2 in the second direction (e.g., the direction parallel to the optical axis I). SH represents the total height of the optical system 100, specifically, SH is the total height of the optical system 100 in the second direction (e.g., the direction parallel to the optical axis I). d12 represents the axial distance from the image side surface of the first lens E1 to the object side surface of the second lens E2, specifically, d12 is the sum of the distance between the image side surface of the first lens E1 and the reflective element P along the optical axis I and the distance between the reflective element P and the object side surface of the second lens E2 along the optical axis II.

[0104] Those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the optical system 100 can be changed to obtain the various results and advantages described in this specification.

[0105] Specific embodiments of the optical system applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings. Example 1

[0106] The following reference Figure 3 , Figure 4 , Figure 5 , Figure 6 as well as Figure 7 The optical system of Embodiment 1 is described. Figure 3 A schematic structural diagram of an optical system in a short-focus state according to Example 1 of the present application is shown. Figure 4 A schematic structural diagram of an optical system in a telephoto state according to Embodiment 1 of the present application is shown.

[0107] like Figure 3 and Figure 4 As shown, the optical system 100 may include a first element group G1 and a second element group G2 arranged in sequence from the object side to the image side. The image side may be provided with an image plane IMA, for example.

[0108] The first element group G1 may include a first lens E1, a reflective element P, and a second lens E2. The second element group G2 may include a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. Specifically, the first lens E1 may be located on the optical axis I and disposed between the object side and the reflective element P. The second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are arranged in sequence from the reflective element P to the image side along the optical axis II. For example, a filter E9 may be disposed between the eighth lens E8 and the image plane IMA. For example, an aperture STO may be disposed between the second lens E2 and the third lens E3.

[0109] The first lens E1 may have positive power, and its object side surface S1 is convex, and its image side surface S2 is convex. The reflective element P may have a reflective surface S3, and the reflective surface S3 is a plane. The second lens E2 may have negative power, and its object side surface S4 is convex, and its image side surface S5 is concave. The third lens E3 may have positive power, and its object side surface S6 is convex, and its image side surface S7 is convex. The fourth lens E4 may have negative power, and its object side surface S8 is convex, and its image side surface S9 is concave. The fifth lens E5 may have positive power, and its object side surface S10 is convex, and its image side surface S11 is convex. The sixth lens E6 may have negative power, and its object side surface S12 is concave, and its image side surface S13 is convex. The seventh lens E7 may have positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The eighth lens E8 may have negative power, and its object-side surface S16 is concave, and its image-side surface S17 is concave. The filter E9 may have an object-side surface S18 and an image-side surface S19. Light from the object passes through each surface S1 to S19 in sequence and is finally imaged on the image plane IMA.

[0110] Table 1 shows the basic parameters of the optical system 100 of Example 1. The units of the radius of curvature and thickness / distance are all millimeters (mm). In this embodiment, the positive or negative value of the value of the radius of curvature of each surface indicates the curvature direction of the surface. When the curvature directions of the surfaces of the lenses on the optical axis I and the optical axis II are the same, the positive and negative properties of the value of the radius of curvature of the surface are opposite. Similarly, the positive or negative value of the value of the thickness / distance of each surface only indicates the direction.

[0111] Table 1

[0112]

[0113] When the optical system 100 switches from the short focus state to the long focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the first element group G1. When the optical system switches from the long focus state to the short focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the image plane IMA.

[0114] like Figure 3 As shown, in the short-focus state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 7.5895 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 4.8435 mm. At this time, the effective focal length EFL of the optical system 100 is 18.50 mm. Figure 4 As shown, in the telephoto state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 2.7902 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 9.6428 mm. At this time, the effective focal length EFL of the optical system 100 is 29.40 mm.

[0115] In this embodiment, the object side surface and the image side surface of any lens among the first lens E1 to the eighth lens E8 are both aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0116] (1)

[0117] Where X(Y) represents the relative distance between the point on the aspherical surface that is Y away from the optical axis and the tangent plane that is tangent to the optical axis of the aspherical surface; Y represents the vertical distance between the point on the aspherical curve and the optical axis; R represents the radius of curvature; K represents the cone coefficient; A i Table 2 shows the cone coefficient K and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0118] Table 2

[0119]

[0120] Figure 5 The axial chromatic aberration curve of the optical system 100 of Example 1 in the short-focus state is shown, which indicates that the convergence point of light of different wavelengths after passing through the optical system 100 deviates. Figure 6 The astigmatism curve of the optical system 100 of Example 1 in the short-focus state is shown, which represents the meridional image curvature and sagittal image curvature corresponding to different image heights. Figure 7 FIG. 1 shows the distortion curve of the optical system 100 of Example 1 in the short focal state, which indicates the distortion magnitude values ​​corresponding to different image heights. Figure 5 , Figure 6 and Figure 7 It can be seen that the optical system 100 of Example 1 can achieve good imaging quality in the short-focus state. Example 2

[0121] The following reference Figure 8 , Fig. 9 , Fig.10 , Fig.11 as well as Fig.12 The optical system of Example 2 is described. In this example and the following examples, some descriptions similar to those of Example 1 will be omitted for the sake of brevity. Figure 8 A schematic structural diagram of an optical system in a short-focus state according to Example 2 of the present application is shown. Fig. 9 A schematic structural diagram of an optical system in a telephoto state according to Embodiment 2 of the present application is shown.

[0122] like Figure 8 and Fig. 9 As shown, the optical system 100 may include a first element group G1 and a second element group G2 arranged in sequence from the object side to the image side. The image side may be provided with an image plane IMA, for example.

[0123] The first element group G1 may include a first lens E1, a reflective element P, and a second lens E2. The second element group G2 may include a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. Specifically, the first lens E1 may be located on the optical axis I and disposed between the object side and the reflective element P. The second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are arranged in sequence from the reflective element P to the image side along the optical axis II. For example, a filter E9 may be disposed between the eighth lens E8 and the image plane IMA. For example, an aperture STO may be disposed between the second lens E2 and the third lens E3.

[0124] The first lens E1 may have positive power, and its object side surface S1 is convex, and its image side surface S2 is convex. The reflective element P may have a reflective surface S3, and the reflective surface S3 is a plane. The second lens E2 may have negative power, and its object side surface S4 is convex, and its image side surface S5 is concave. The third lens E3 may have positive power, and its object side surface S6 is convex, and its image side surface S7 is convex. The fourth lens E4 may have negative power, and its object side surface S8 is convex, and its image side surface S9 is concave. The fifth lens E5 may have positive power, and its object side surface S10 is convex, and its image side surface S11 is concave. The sixth lens E6 may have positive power, and its object side surface S12 is concave, and its image side surface S13 is convex. The seventh lens E7 may have positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The eighth lens E8 may have negative power, and its object-side surface S16 is concave, and its image-side surface S17 is concave. The filter E9 may have an object-side surface S18 and an image-side surface S19. Light from the object passes through each surface S1 to S19 in sequence and is finally imaged on the image plane IMA.

[0125] Table 3 shows basic parameters of the optical system 100 of Example 2, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0126] Table 3

[0127]

[0128] When the optical system 100 switches from the short focus state to the long focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the first element group G1. When the optical system switches from the long focus state to the short focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the image plane IMA.

[0129] like Figure 8 As shown, in the short-focus state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 8.5981 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 5.8528 mm. At this time, the effective focal length EFL of the optical system 100 is 25.36 mm. Fig. 9As shown, in the telephoto state of the optical system 100, the distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 3.1970 mm, and the distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 11.2539 mm. At this time, the effective focal length EFL of the optical system 100 is 38.00 mm.

[0130] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are aspherical surfaces. Table 4 shows the cone coefficient K and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A5 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0131] Table 4

[0132]

[0133] Fig.10 The axial chromatic aberration curve of the optical system 100 of Example 2 in the short-focus state is shown, which indicates that the convergence point of light of different wavelengths after passing through the optical system 100 deviates. Fig.11 The astigmatism curve of the optical system 100 of Example 2 in the short-focus state is shown, which represents the meridional image curvature and sagittal image curvature corresponding to different image heights. Fig.12 FIG. 2 shows the distortion curve of the optical system 100 of Example 2 in the short-focus state, which indicates the distortion magnitude values ​​corresponding to different image heights. Fig.10 , Fig.11 and Fig.12 It can be seen that the optical system 100 of Example 2 can achieve good imaging quality in the short-focus state. Example 3

[0134] The following reference Fig.13 , Fig.14 , Fig.15 , Fig.16 as well as Fig.17 The optical system of Embodiment 3 is described. Fig.13 A schematic structural diagram of an optical system in a short-focus state according to Example 3 of the present application is shown. Fig.14 A schematic structural diagram of an optical system in a telephoto state according to Example 3 of the present application is shown.

[0135] like Fig.13and Fig.14 As shown, the optical system 100 may include a first element group G1 and a second element group G2 arranged in sequence from the object side to the image side. The image side may be provided with an image plane IMA, for example.

[0136] The first element group G1 may include a first lens E1, a reflective element P, and a second lens E2. The second element group G2 may include a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. Specifically, the first lens E1 may be located on the optical axis I and disposed between the object side and the reflective element P. The second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are arranged in sequence from the reflective element P to the image side along the optical axis II. For example, a filter E9 may be disposed between the eighth lens E8 and the image plane IMA. For example, an aperture STO may be disposed between the second lens E2 and the third lens E3.

[0137] The first lens E1 may have positive power, and its object side surface S1 is convex, and its image side surface S2 is convex. The reflective element P may have a reflective surface S3, and the reflective surface S3 is a plane. The second lens E2 may have negative power, and its object side surface S4 is convex, and its image side surface S5 is concave. The third lens E3 may have positive power, and its object side surface S6 is convex, and its image side surface S7 is convex. The fourth lens E4 may have negative power, and its object side surface S8 is convex, and its image side surface S9 is concave. The fifth lens E5 may have positive power, and its object side surface S10 is convex, and its image side surface S11 is convex. The sixth lens E6 may have negative power, and its object side surface S12 is concave, and its image side surface S13 is convex. The seventh lens E7 may have positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The eighth lens E8 may have negative power, and its object-side surface S16 is concave, and its image-side surface S17 is concave. The filter E9 may have an object-side surface S18 and an image-side surface S19. Light from the object passes through each surface S1 to S19 in sequence and is finally imaged on the image plane IMA.

[0138] Table 5 shows basic parameters of the optical system 100 of Example 3, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0139] Table 5

[0140]

[0141] When the optical system 100 switches from the short focus state to the long focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the first element group G1. When the optical system switches from the long focus state to the short focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the image plane IMA.

[0142] like Fig.13 As shown, in the short-focus state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 7.3343 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 7.4539 mm. At this time, the effective focal length EFL of the optical system 100 is 25.37 mm. Fig.14 As shown, in the telephoto state of the optical system 100, the distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 2.1495 mm, and the distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 12.6386 mm. At this time, the effective focal length EFL of the optical system 100 is 38.00 mm.

[0143] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are aspherical surfaces. Table 6 shows the cone coefficient K and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A5 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0144] Table 6

[0145]

[0146] Fig.15 The axial chromatic aberration curve of the optical system 100 of Example 3 in the short-focus state is shown, which indicates that the convergence point of light of different wavelengths after passing through the optical system 100 deviates. Fig.16 The astigmatism curve of the optical system 100 of Example 3 in the short-focus state is shown, which represents the meridional image curvature and sagittal image curvature corresponding to different image heights. Fig.17 FIG. 1 shows the distortion curve of the optical system 100 of Example 3 in the short focal state, which indicates the distortion magnitude values ​​corresponding to different image heights. Fig.15 , Fig.16 and Fig.17 It can be seen that the optical system 100 of Example 3 can achieve good imaging quality in the short-focus state. Example 4

[0147] The following reference Fig.18 , Fig.19 , Fig. 20 , Fig.21 as well as Fig. 22 The optical system of Embodiment 4 is described. Fig.18 A schematic structural diagram of an optical system in a short-focus state according to Example 4 of the present application is shown. Fig.19 A schematic structural diagram of an optical system in a telephoto state according to Example 4 of the present application is shown.

[0148] like Fig.18 and Fig.19 As shown, the optical system 100 may include a first element group G1 and a second element group G2 arranged in sequence from the object side to the image side. The image side may be provided with an image plane IMA, for example.

[0149] The first element group G1 may include a first lens E1, a reflective element P, and a second lens E2. The second element group G2 may include a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. Specifically, the first lens E1 may be located on the optical axis I and disposed between the object side and the reflective element P. The second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are arranged in sequence from the reflective element P to the image side along the optical axis II. For example, a filter E9 may be disposed between the eighth lens E8 and the image plane IMA. For example, an aperture STO may be disposed between the second lens E2 and the third lens E3.

[0150] The first lens E1 may have positive power, and its object side surface S1 is convex, and its image side surface S2 is convex. The reflective element P may have a reflective surface S3, and the reflective surface S3 is a plane. The second lens E2 may have negative power, and its object side surface S4 is convex, and its image side surface S5 is concave. The third lens E3 may have positive power, and its object side surface S6 is convex, and its image side surface S7 is convex. The fourth lens E4 may have negative power, and its object side surface S8 is convex, and its image side surface S9 is concave. The fifth lens E5 may have positive power, and its object side surface S10 is convex, and its image side surface S11 is concave. The sixth lens E6 may have negative power, and its object side surface S12 is concave, and its image side surface S13 is convex. The seventh lens E7 may have positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The eighth lens E8 may have negative power, and its object-side surface S16 is concave, and its image-side surface S17 is concave. The filter E9 may have an object-side surface S18 and an image-side surface S19. Light from the object passes through each surface S1 to S19 in sequence and is finally imaged on the image plane IMA.

[0151] Table 7 shows basic parameters of the optical system 100 of Example 4, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0152] Table 7

[0153]

[0154] When the optical system 100 switches from the short focus state to the long focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the first element group G1. When the optical system switches from the long focus state to the short focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the image plane IMA.

[0155] like Fig.18 As shown, in the short-focus state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 6.9634 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 4.9042 mm. At this time, the effective focal length EFL of the optical system 100 is 16.60 mm. Fig.19 As shown, in the telephoto state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 2.6090 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 9.2585 mm. At this time, the effective focal length EFL of the optical system 100 is 26.10 mm.

[0156] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are aspherical surfaces. Table 8 shows the cone coefficient K and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A5 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0157] Table 8

[0158]

[0159] Fig. 20The axial chromatic aberration curve of the optical system 100 of Example 4 in the short-focus state is shown, which indicates that the focusing point of light rays of different wavelengths deviates after passing through the optical system 100 . Fig.21 The astigmatism curve of the optical system 100 of Example 4 in the short-focus state is shown, which represents the meridional image curvature and sagittal image curvature corresponding to different image heights. Fig. 22 FIG. 4 shows the distortion curve of the optical system 100 of Example 4 in the short focal state, which indicates the distortion magnitude values ​​corresponding to different image heights. Fig. 20 , Fig.21 and Fig. 22 It can be seen that the optical system 100 of Example 4 can achieve good imaging quality in the short-focus state. Example 5

[0160] The following reference Fig.23 , Fig.24 , Fig.25 , Fig.26 as well as Fig. 27 The optical system of Embodiment 5 is described. Fig.23 A schematic structural diagram of an optical system in a short-focus state according to Example 5 of the present application is shown. Fig.24 A schematic structural diagram of an optical system in a telephoto state according to Example 5 of the present application is shown.

[0161] like Fig.23 and Fig.24 As shown, the optical system 100 may include a first element group G1 and a second element group G2 arranged in sequence from the object side to the image side. The image side may be provided with an image plane IMA, for example.

[0162] The first element group G1 may include a first lens E1, a reflective element P, and a second lens E2. The second element group G2 may include a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. Specifically, the first lens E1 may be located on the optical axis I and disposed between the object side and the reflective element P. The second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are arranged in sequence from the reflective element P to the image side along the optical axis II. For example, a filter E9 may be disposed between the eighth lens E8 and the image plane IMA. For example, an aperture STO may be disposed between the second lens E2 and the third lens E3.

[0163] The first lens E1 may have positive power, and its object side surface S1 is convex, and its image side surface S2 is convex. The reflective element P may have a reflective surface S3, and the reflective surface S3 is a plane. The second lens E2 may have negative power, and its object side surface S4 is convex, and its image side surface S5 is concave. The third lens E3 may have positive power, and its object side surface S6 is convex, and its image side surface S7 is convex. The fourth lens E4 may have negative power, and its object side surface S8 is convex, and its image side surface S9 is concave. The fifth lens E5 may have positive power, and its object side surface S10 is convex, and its image side surface S11 is convex. The sixth lens E6 may have negative power, and its object side surface S12 is concave, and its image side surface S13 is convex. The seventh lens E7 may have positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The eighth lens E8 may have negative power, and its object-side surface S16 is concave, and its image-side surface S17 is concave. The filter E9 may have an object-side surface S18 and an image-side surface S19. Light from the object passes through each surface S1 to S19 in sequence and is finally imaged on the image plane IMA.

[0164] Table 9 shows basic parameters of the optical system 100 of Example 5, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0165] Table 9

[0166]

[0167] When the optical system 100 switches from the short focus state to the long focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the first element group G1. When the optical system switches from the long focus state to the short focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the image plane IMA.

[0168] like Fig.23 As shown, in the short-focus state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 7.0500 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 6.5703 mm. At this time, the effective focal length EFL of the optical system 100 is 22.76 mm. Fig.24As shown, in the telephoto state of the optical system 100, the distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 2.0921 mm, and the distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 11.5282 mm. At this time, the effective focal length EFL of the optical system 100 is 34.13 mm.

[0169] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are aspherical surfaces. Table 10 shows the cone coefficient K and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0170] Table 10

[0171]

[0172] Fig.25 The axial chromatic aberration curve of the optical system 100 of Example 5 in the short-focus state is shown, which indicates that the convergence point of light of different wavelengths after passing through the optical system 100 deviates. Fig.26 The astigmatism curve of the optical system 100 of Example 5 in the short-focus state is shown, which represents the meridional image curvature and sagittal image curvature corresponding to different image heights. Fig. 27 FIG. 1 shows the distortion curve of the optical system 100 of Example 5 in the short focal state, which indicates the distortion magnitude values ​​corresponding to different image heights. Fig.25 , Fig.26 as well as Fig. 27 It can be seen that the optical system 100 of Example 5 can achieve good imaging quality in the short-focus state. Example 6

[0173] The following reference Fig.28 , Fig.29 , Fig.30 , Fig.31 as well as Fig.32 The optical system of Embodiment 6 is described. Fig.28 A schematic diagram of the structure of the optical system in a short-focus state according to Example 6 of the present application is shown. Fig.29 A schematic structural diagram of the optical system in a telephoto state according to Example 6 of the present application is shown.

[0174] like Fig.28 and Fig.29 As shown, the optical system 100 may include a first element group G1 and a second element group G2 arranged in sequence from the object side to the image side. The image side may be provided with an image plane IMA, for example.

[0175] The first element group G1 may include a first lens E1, a reflective element P, and a second lens E2. The second element group G2 may include a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. Specifically, the first lens E1 may be located on the optical axis I and disposed between the object side and the reflective element P. The second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are arranged in sequence from the reflective element P to the image side along the optical axis II. For example, a filter E9 may be disposed between the eighth lens E8 and the image plane IMA. For example, an aperture STO may be disposed between the second lens E2 and the third lens E3.

[0176] The first lens E1 may have positive power, and its object side surface S1 is convex, and its image side surface S2 is convex. The reflective element P may have a reflective surface S3, and the reflective surface S3 is a plane. The second lens E2 may have negative power, and its object side surface S4 is convex, and its image side surface S5 is concave. The third lens E3 may have positive power, and its object side surface S6 is convex, and its image side surface S7 is convex. The fourth lens E4 may have negative power, and its object side surface S8 is convex, and its image side surface S9 is concave. The fifth lens E5 may have positive power, and its object side surface S10 is convex, and its image side surface S11 is convex. The sixth lens E6 may have negative power, and its object side surface S12 is concave, and its image side surface S13 is convex. The seventh lens E7 may have positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The eighth lens E8 may have negative power, and its object-side surface S16 is concave, and its image-side surface S17 is concave. The filter E9 may have an object-side surface S18 and an image-side surface S19. Light from the object passes through each surface S1 to S19 in sequence and is finally imaged on the image plane IMA.

[0177] Table 11 shows basic parameters of the optical system 100 of Example 6, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0178] Table 11

[0179]

[0180] When the optical system 100 switches from the short focus state to the long focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the first element group G1. When the optical system switches from the long focus state to the short focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the image plane IMA.

[0181] like Fig.28 As shown, in the short-focus state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 6.8531 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 6.7310 mm. At this time, the effective focal length EFL of the optical system 100 is 22.76 mm. Fig.29 As shown, in the telephoto state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 2.0477 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 11.5364 mm. At this time, the effective focal length EFL of the optical system 100 is 34.13 mm.

[0182] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are aspherical surfaces. Table 12 shows the cone coefficient K and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0183] Table 12

[0184]

[0185] Fig.30 The axial chromatic aberration curve of the optical system 100 of Example 6 in the short-focus state is shown, which indicates that the convergence point of light of different wavelengths after passing through the optical system 100 deviates. Fig.31 The astigmatism curve of the optical system 100 of Example 6 in the short-focus state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Fig.32FIG. 1 shows the distortion curve of the optical system 100 of Example 6 in the short focal state, which indicates the distortion magnitude values ​​corresponding to different image heights. Fig.30 , Fig.31 as well as Fig.32 It can be seen that the optical system 100 of Example 6 can achieve good imaging quality in the short-focus state. Example 7

[0186] The following reference Fig.33 , Fig.34 , Fig.35 , Fig.36 as well as Fig.37 The optical system of Example 7 is described. Fig.33 A schematic structural diagram of an optical system in a short-focus state according to Example 7 of the present application is shown. Fig.34 A schematic structural diagram of an optical system in a telephoto state according to Example 7 of the present application is shown.

[0187] like Fig.33 and Fig.34 As shown, the optical system 100 may include a first element group G1 and a second element group G2 arranged in sequence from the object side to the image side. The image side may be provided with an image plane IMA, for example.

[0188] The first element group G1 may include a first lens E1, a reflective element P, and a second lens E2. The second element group G2 may include a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, and an eighth lens E8. Specifically, the first lens E1 may be located on the optical axis I and disposed between the object side and the reflective element P. The second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are arranged in sequence from the reflective element P to the image side along the optical axis II. For example, a filter E9 may be disposed between the eighth lens E8 and the image plane IMA. For example, an aperture STO may be disposed between the second lens E2 and the third lens E3.

[0189] The first lens E1 may have positive power, and its object side surface S1 is convex, and its image side surface S2 is convex. The reflective element P may have a reflective surface S3, and the reflective surface S3 is a plane. The second lens E2 may have negative power, and its object side surface S4 is convex, and its image side surface S5 is concave. The third lens E3 may have positive power, and its object side surface S6 is convex, and its image side surface S7 is convex. The fourth lens E4 may have negative power, and its object side surface S8 is convex, and its image side surface S9 is concave. The fifth lens E5 may have positive power, and its object side surface S10 is convex, and its image side surface S11 is concave. The sixth lens E6 may have negative power, and its object side surface S12 is concave, and its image side surface S13 is convex. The seventh lens E7 may have positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The eighth lens E8 may have negative power, and its object-side surface S16 is concave, and its image-side surface S17 is concave. The filter E9 may have an object-side surface S18 and an image-side surface S19. Light from the object passes through each surface S1 to S19 in sequence and is finally imaged on the image plane IMA.

[0190] Table 13 shows basic parameters of the optical system 100 of Example 7, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm).

[0191] Table 13

[0192]

[0193] When the optical system 100 switches from the short focus state to the long focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the first element group G1. When the optical system switches from the long focus state to the short focus state, the position of the first element group G1 is fixed, and the second element group G2 moves along the optical axis II toward the image plane IMA.

[0194] like Fig.33 As shown, in the short-focus state of the optical system 100, the spacing distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 12.1705 mm, and the spacing distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 4.7754 mm. At this time, the effective focal length EFL of the optical system 100 is 11.98 mm. Fig.34As shown, in the telephoto state of the optical system 100, the distance W1 between the first element group G1 and the second element group G2 (i.e., the image side surface S5 of the second lens E2 and the object side surface S6 of the third lens E3) on the optical axis II is 2.6193 mm, and the distance W2 between the second element group G2 and the filter E9 (i.e., the image side surface S17 of the eighth lens E8 and the object side surface S18 of the filter E9) on the optical axis II is 14.3266 mm. At this time, the effective focal length EFL of the optical system 100 is 31.95 mm.

[0195] In this embodiment, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are aspherical surfaces. Table 14 shows the cone coefficient K and the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, A52, A53, A54, A55, A56, A57, A 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0196] Table 14

[0197]

[0198] Fig.35 The axial chromatic aberration curve of the optical system 100 of Example 7 in the short-focus state is shown, which indicates that the convergence point of light of different wavelengths after passing through the optical system 100 deviates. Fig.36 The astigmatism curve of the optical system 100 of Example 7 in the short-focus state is shown, which represents the meridional image curvature and sagittal image curvature corresponding to different image heights. Fig.37 FIG. 1 shows the distortion curve of the optical system 100 of Example 7 in the short focal state, which indicates the distortion magnitude values ​​corresponding to different image heights. Fig.35 , Fig.36 as well as Fig.37 It can be seen that the optical system 100 of Example 7 can achieve good imaging quality in the short-focus state.

[0199] Table 15 shows the values ​​of FOV, D1, D2, FG1, FG2, D2x, EPDx, d12, D2y, EPDy, SL and DL of each embodiment in Embodiments 1 to 7. The unit of FOV is degree (°), and the units of other parameters are millimeters (mm). In addition, FOV, EPDx and EPDy are the values ​​of the optical system 100 in the short-focus state.

[0200] Table 15

[0201]

[0202] Table 16 shows the values ​​of the conditional expressions of each embodiment in Embodiments 1 to 7. The values ​​of the conditional expressions involving FOV, EFL, EPDx and EPDy in Table 16 are all calculated by the values ​​of FOV, EFL, EPDx and EPDy of the optical system 100 in the short focus state.

[0203] Table 16

[0204]

[0205] The present application also provides a camera module, which may be, for example, a periscope camera module. The camera module may include the above-mentioned optical system and an imaging element for converting an optical image formed by the optical system into an electrical signal.

[0206] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. An optical system, characterized in that: It is composed of a first lens group and a second lens group arranged in sequence from the object side to the image side along the optical axis; The first lens group is composed of a first lens with positive optical power, a reflecting element, and a second lens with negative optical power arranged in sequence from the object side to the image side; wherein, the reflecting element is used to reflect the light rays emitted from the first lens; and The second lens group has positive optical power and is composed of a third lens with positive optical power, a fourth lens with negative optical power, a fifth lens with positive optical power, a sixth lens, a seventh lens with positive optical power, and an eighth lens with negative optical power arranged in sequence from the first lens group to the image side; The second lens group is movable along the optical axis direction to switch the optical system between a short focal length state and a long focal length state; Wherein, the optical system satisfies: 0.39 < DL / DEFL < 0.49, where DL is the movable stroke of the second lens group, and DEFL is the change in the effective focal length of the optical system in the long focal length state and its effective focal length in the short focal length state.

2. The optical system according to claim 1, wherein: The optical system satisfies in the short focal length state: 0 < tan(FOV / 2) < 0.35, where FOV is the maximum field of view angle FOV of the optical system.

3. The optical system according to claim 1, wherein: The optical system satisfies: 5.2 < D1 / CT1 < 6.0, where D1 is the maximum effective aperture of the first lens, and CT1 is the central thickness of the first lens on the optical axis.

4. The optical system according to claim 1, wherein: The optical system satisfies: 5.5 < D2 / CT2 < 7.5, where D2 is the maximum effective aperture of the second lens, and CT2 is the central thickness of the second lens on the optical axis.

5. The optical system according to claim 1, wherein: The optical system satisfies: 3.6 < |f1 / f2| < 5.6, where f1 is the effective focal length of the first lens, and f2 is the effective focal length of the second lens.

6. The optical system according to claim 1, wherein: The optical system satisfies in the short focal length state: 1.2 < |FG1 / EFL| < 1.65, where FG1 is the effective focal length of the first lens group, and EFL is the effective focal length of the optical system.

7. The optical system according to claim 1, wherein: The optical system satisfies: 2.0 < |FG1 / FG2| < 2.5, where FG1 is the effective focal length of the first lens group, and FG2 is the effective focal length of the second lens group.

8. The optical system according to claim 1, wherein: The optical system meets the following requirements in the short-focus state: 0.05mm -1 <D2x / EPDx / d12<0.09mm -1 , wherein D2x is the maximum effective semi-aperture of the first lens in the first direction, EPDx is the entrance pupil diameter of the optical system in the first direction, and d12 is the axial distance from the image side surface of the first lens to the object side surface of the second lens.

9. The optical system according to claim 1, wherein: The optical system meets the following requirements in the short-focus state: 0.05mm -1 <D2y / EPDy / d12<0.09mm -1 , wherein D2y is the maximum effective semi-aperture of the second lens in the second direction, EPDy is the entrance pupil diameter of the optical system in the second direction, and d12 is the distance between the image side surface of the first lens and the object side surface of the second lens on the optical axis.

10. The optical system according to claim 1, wherein: The optical system satisfies in the short focal length state: 0.25 < EFL / SL < 0.55, where EFL is the effective focal length of the optical system, and SL is the total length of the optical system in the preset principal optical axis direction.

11. The optical system according to any one of claims 1 to 10, wherein: The optical axis includes a first optical axis and a second optical axis at a preset angle, and the second optical axis is the preset principal optical axis; The reflecting element includes a plane mirror, the plane mirror receives the light rays emitted from the first lens along the direction of the first optical axis, and reflects the light rays and emits them along the direction of the second optical axis to the second lens.

12. A camera module, characterized in that: It includes the optical system according to any one of claims 1 to 11 and an imaging element for converting the optical image formed by the optical system into an electrical signal.

Images