Optical image capturing system

Abstract

The utility model relates to an optical imaging system. The optical imaging system includes: first, second, third and fourth lens groups each including a plurality of lenses, sequentially disposed along an optical axis, and each including a plurality of lenses, in which each of the first and fourth lens groups has a positive refractive power, and a negative refractive power; the optical imaging system further includes an aperture disposed between the third lens group and the fourth lens group, the first lens group, the aperture, and the fourth lens group are fixed, and the second lens group and the third lens group are configured to be movable along an optical axis, the optical imaging system further includes a reflective member disposed in front of the first lens group, the reflective member includes a reflective surface configured to change an optical path of the optical imaging system, and the fourth lens group is a lens group disposed closest to the imaging plane.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0196944, filed on December 29, 2023, with the Korean Intellectual Property Office, and Korean Patent Application No. 10-2024-0071804, filed on May 31, 2024, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] This disclosure relates to optical imaging systems. Background Technology

[0004] In recent years, camera modules have been adopted as a fundamental feature in portable electronic devices, including smartphones.

[0005] In addition, recently, in order to indirectly achieve the optical zoom effect, a method has been proposed to install multiple camera modules with different focal lengths on a portable electronic device.

[0006] However, this method not only requires multiple camera modules for optical zoom effects, but there are also differences in the field of view between the multiple camera modules. Therefore, when capturing images at intermediate magnification, imaging processing is required through software instead of optical zoom, which may lead to problems with image quality degradation. Utility Model Content

[0007] This summary is provided to present the selection of concepts in a simplified form, while these concepts are further described in the following detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0008] In one general aspect, an optical imaging system includes: a first lens group, a second lens group, a third lens group, and a fourth lens group, arranged sequentially along the optical axis of the optical imaging system from the object side of the optical imaging system toward the imaging surface of the optical imaging system, and each including multiple lenses, wherein each of the first and fourth lens groups generally has positive refractive power, the optical imaging system also includes an aperture disposed between the third and fourth lens groups, the first lens group, the aperture, and the fourth lens group being disposed at fixed positions on the optical axis, and the second and third lens groups being configured to be movable along the optical axis, the optical imaging system also includes a reflective member disposed in front of the first lens group, the reflective member including a reflective surface configured to change the optical path of the optical imaging system, and the fourth lens group being the lens group disposed closest to the imaging surface.

[0009] 0.95≤Mw / Mt≤1.05 can be satisfied, where Mw is a magnification of the fourth lens group in a wide angle mode of the optical imaging system when the optical imaging system is focused on an object at infinity, and Mt is a magnification of the fourth lens group in a telephoto mode of the optical imaging system when the optical imaging system is focused on an object at infinity.

[0010] 0.9≤L14 / L4≤1.2 can be satisfied, where L14 is a distance along the optical axis from an image side surface of a lens closest to the second lens group among lenses included in the first lens group to an object side surface of a lens closest to the third lens group among lenses included in the fourth lens group, and L4 is a distance along the optical axis from the object side surface of the lens closest to the third lens group among the lenses included in the fourth lens group to the image plane.

[0011] 0.8≤D11 / D_last≤1.3 can be satisfied, where D11 is an effective diameter of an object side surface of a lens closest to the reflection member among lenses included in the first lens group, and D_last is an effective diameter of an image side surface of a lens closest to the image plane among lenses included in the fourth lens group.

[0012] 0.5≤D41 / (2×IMG HT)≤0.8 can be satisfied, where D41 is an effective diameter of an object side surface of a lens closest to the third lens group among lenses included in the fourth lens group, and IMG HT is half of a diagonal length of the image plane.

[0013] 1.0≤T_dG3 / I_dG3≤1.4 can be satisfied, where T_dG3 is a maximum movement amount of the third lens group in a telephoto mode of the optical imaging system, and I_dG3 is a maximum movement amount of the third lens group when the optical imaging system is focused on an object at infinity.

[0014] 1.5≤fG1 / D_last≤2.5 can be satisfied, where fG1 is a focal length of the first lens group, and D_last is an effective diameter of an image side surface of a lens closest to the image plane among lenses included in the fourth lens group.

[0015]

[0016] -0.6≤(R13-R14) / (R13+R14)≤-0.2 can be satisfied, where R13 is a curvature radius of an object side surface of a lens closest to the third lens group among lenses included in the fourth lens group, and R14 is a curvature radius of an image side surface of a lens closest to the third lens group among the lenses included in the fourth lens group.

[0017] ​1.5 ≤ ft / L4 ≤ 2.2, where ft is a total focal length of the optical imaging system in a telephoto mode of the optical imaging system when the optical imaging system is focused on an object at infinity, and L4 is a distance from an object side surface of a lens closest to the third lens group among lenses included in the fourth lens group to an image plane along an optical axis.

[0018] The second lens group can have a negative refractive power, and the third lens group can have a positive refractive power.

[0019] The first lens group can include a first lens and a second lens, the first lens and the second lens can have refractive powers having opposite signs, and among the first lens and the second lens, an Abbe number of the lens having a positive refractive power can be greater than 50, and an Abbe number of the lens having a negative refractive power can be less than 35.

[0020] The second lens group can include a third lens and a fourth lens, the third lens and the fourth lens can have refractive powers having opposite signs, and among the third lens and the fourth lens, an Abbe number of the lens having a positive refractive power can be less than 21, and an Abbe number of the lens having a negative refractive power can be greater than 45.

[0021] The third lens group can include a fifth lens and a sixth lens, the fifth lens and the sixth lens can have refractive powers having opposite signs, and among the fifth lens and the sixth lens, an Abbe number of the lens having a positive refractive power can be greater than 50, and an Abbe number of the lens having a negative refractive power can be less than 30.

[0022] The fourth lens group can include a seventh lens, an eighth lens, a ninth lens, and a tenth lens, and the seventh lens can have an object side surface convex in a paraxial region thereof and an Abbe number greater than 50.

[0023] An aperture can be disposed in front of the seventh lens, and the seventh lens can have a positive refractive power.

[0024] The ninth lens or the tenth lens can have at least one inflection point on one or both of an object side surface and an image side surface thereof.

[0025] In another general aspect, an optical imaging system includes: a first lens group, a second lens group, a third lens group, and a fourth lens group, sequentially disposed along an optical axis of the optical imaging system from an object side of the optical imaging system toward an image plane of the optical imaging system, and each including a plurality of lenses; and an aperture disposed between the third lens group and the fourth lens group, wherein each of the first lens group and the fourth lens group has a positive refractive power overall and is disposed at a fixed position on the optical axis, the second lens group is configured to be movable along the optical axis to adjust a focal length of the optical imaging system between a wide-angle mode of the optical imaging system and a telephoto mode of the optical imaging system, the third lens group is configured to be movable along the optical axis to adjust a focal position of the optical imaging system when the second lens group is moved along the optical axis to adjust the focal length of the optical imaging system, and satisfies 0.95 ≤ Mw / Mt ≤ 1.05, where Mw is a magnification of the fourth lens group in the wide-angle mode when the optical imaging system is focused on an object at infinity, and Mt is a magnification of the fourth lens group in the telephoto mode when the optical imaging system is focused on the object at infinity.

[0026] 1.0 ≤ T_dG3 / I_dG3 ≤ 1.4 can be satisfied, where T_dG3 is an amount of movement of the third lens group between a position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at a close-up position and a position of the third lens group in the telephoto mode when the optical imaging system is focused on the object at infinity, and I_dG3 is an amount of movement of the third lens group between a position of the third lens group in the wide-angle mode when the optical imaging system is focused on the object at infinity and the position of the third lens group in the telephoto mode when the optical imaging system is focused on the object at infinity.

[0027] The second lens group can have a negative refractive power overall, and the third lens group can have a positive refractive power overall.

[0028] The aperture can be aligned with a vertex of an object side face of a lens closest to the third lens group among the lenses included in the fourth lens group.

[0029] In another general aspect, an optical imaging system includes: a first lens group, a second lens group, a third lens group, and a fourth lens group, which are sequentially disposed along an optical axis of the optical imaging system from an object side of the optical imaging system toward an image plane of the optical imaging system and each include a plurality of lenses; and an aperture disposed between the third lens group and the fourth lens group, wherein each of the first lens group and the fourth lens group has a positive refractive power overall and is disposed at a fixed position on the optical axis, the second lens group is configured to be movable along the optical axis to adjust a focal length of the optical imaging system between a wide-angle mode of the optical imaging system and a telephoto mode of the optical imaging system, the third lens group is configured to be movable along the optical axis to adjust a focal position of the optical imaging system when the second lens group is moved along the optical axis to adjust the focal length of the optical imaging system, and satisfies 0.9 ≤ L14 / L4 ≤ 1.2, where L14 is a distance along the optical axis from an image side surface of a lens closest to the second lens group among the lenses included in the first lens group to an object side surface of a lens closest to the third lens group among the lenses included in the fourth lens group, and L4 is a distance along the optical axis from the object side surface of the lens closest to the third lens group among the lenses included in the fourth lens group to the image plane.

[0030] 0.8 ≤ D11 / D_last ≤ 1.3 can be satisfied, where D11 is an effective diameter of an object side surface of a lens closest to an object side of the optical imaging system among the lenses included in the first lens group, and D_last is an effective diameter of an image side surface of a lens closest to the image plane among the lenses included in the fourth lens group.

[0031] The second lens group can have a negative refractive power overall, and the third lens group can have a positive refractive power overall.

[0032] The aperture can be aligned with a vertex of an object side surface of a lens closest to the third lens group among the lenses included in the fourth lens group.

[0033] Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a view illustrating a wide-angle mode of an optical imaging system according to a first embodiment of the disclosure.

[0035] Figure 2 is a view illustrating a telephoto mode of an optical imaging system according to the first embodiment of the disclosure.

[0036] Figure 3 is a view illustrating a wide-angle mode of an optical imaging system according to a second embodiment of the disclosure.

[0037] Figure 4 is a view illustrating a telephoto mode of the optical imaging system according to the second embodiment of the present disclosure.

[0038] Figure 5 is a view illustrating a wide-angle mode of the optical imaging system according to the third embodiment of the present disclosure.

[0039] Figure 6 is a view illustrating a telephoto mode of the optical imaging system according to the third embodiment of the present disclosure.

[0040] Throughout the drawings and specific embodiments, identical reference numerals indicate identical elements. The drawings can not be to scale and the dimensions, proportions, and shapes of the elements in the drawings can be exaggerated for clarity, illustration and convenience. DETAILED DESCRIPTION

[0041] The following detailed description is presented to aid the reader in gaining a comprehensive understanding of the methods, apparatuses, and / or systems described herein. However, various changes, modifications, and equivalents can be used, and the

[0042] The features described herein can be implemented in different forms and are not to be construed as limited to the examples described herein. Rather, descriptions of the examples are provided as part of this disclosure to convey the substance of the methods, apparatuses, and / or systems described herein from which numerous possible implementations can be derived, in accordance with the disclosure.

[0043] Throughout the specification, when an element (such as a layer, region, or substrate) is referred to as being "on" another element, it can be directly on the other element or one or more intervening elements can also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present.

[0044] As used herein, the term "and / or" includes any one of the associated listed items, as well as any combination of any two or more of the associated listed items.

[0045] Although terms such as "first", "second", and "third" can be used herein to describe various components, assemblies, regions, layers or parts, these components, assemblies, regions, layers or parts are not limited by the terms. Rather, the terms are only used to distinguish one component, assembly, region, layer or part from another component, assembly, region, layer or part. Thus, a first component, a first assembly, a first region, a first layer or a first part mentioned in examples described herein can also be referred to as a second component, a second assembly, a second region, a second layer or a second part without departing from the teachings of the examples.

[0046] For ease of description, spatial relative terms such as "upper", "top", "lower", and "bottom" can be used herein to describe the relationship of one element to another element as shown in the drawings. In addition to the orientation depicted in the drawings, such spatial relative terms are intended to include different orientations of the device in use or operation. For example, if the device in the drawings is turned over, an element described as being "above" or "upper" relative to another element would then be oriented "below" or "lower" relative to the other element. Accordingly, the term "above" includes both the above and below orientations depending on the spatial orientation of the device. The device can also be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relative terms used herein will be interpreted accordingly.

[0047] The terms used herein are used only to describe various examples, and are not intended to limit the present disclosure. The words "one", "a", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprise", "include" and "have" specify the presence of stated features, numbers, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, numbers, operations, components, elements, and / or combinations thereof.

[0048] In the drawings, the thickness, size, and shape of the lens can be slightly exaggerated for ease of illustration, and in particular, the shape of the lens surface in the drawings is presented only as an example, but is not limited thereto.

[0049] The optical imaging system according to the exemplary embodiments of the present disclosure can be mounted in a portable electronic device. For example, the optical imaging system can be a component of a camera module mounted in a portable electronic device. The portable electronic device can be a portable electronic device such as a mobile communication terminal, a smart phone, or a tablet PC.

[0050] In the exemplary embodiments, the first lens (or the frontmost lens) is a lens closest to the object side of the optical imaging system, and the last lens (or the rearmost lens) refers to a lens closest to the imaging surface (or the image sensor) of the optical imaging system.

[0051] Also in this specification, the numerical values of the radius of curvature of a lens surface, the thickness of a lens, the distance between lenses or other elements, the focal length of a lens, and other quantities are expressed in millimeters, and the field of view (FOV) of an optical imaging system is expressed in degrees.

[0052] Also in the description of the shape of each lens, the statement that the surface of a lens is convex means that the surface is convex in the paraxial region of the surface, and the statement that the surface of a lens is concave means that the surface is concave in the paraxial region of the surface.

[0053] Therefore, even if the surface of a lens is described as convex, the edge portion of the surface can be concave. Similarly, even if the surface of a lens is described as concave, the edge portion of the surface can be convex.

[0054] The paraxial region of a lens surface is the central portion of the lens surface around the optical axis of the lens surface, in which light rays incident to the lens surface form a small angle θ with the optical axis, and the approximations sin θ ≈ θ, tan θ ≈ θ, and cos θ ≈ 1 are valid.

[0055] The imaging surface can be a virtual surface on which an image of an object is focused by the optical imaging system. Alternatively, the imaging surface can be one surface of an image sensor on which an image is focused.

[0056] The optical imaging system according to an example embodiment of the present disclosure includes a plurality of lens groups. For example, the optical imaging system can include a first lens group, a second lens group, a third lens group, and a fourth lens group.

[0057] Each of the first lens group to the fourth lens group includes a plurality of lenses. In an example embodiment, the optical imaging system can include ten lenses.

[0058] In an example embodiment, the optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens, which are sequentially disposed from the object side of the optical imaging system toward the image side of the optical imaging system along the optical axis of the optical imaging system.

[0059] The optical imaging system according to an example embodiment of the present disclosure can further include a reflection member having a reflection surface for changing the optical path of the optical imaging system. For example, the reflection member can be a mirror or a prism.

[0060] The optical path through the reflection member can be bent so as to be elongated in a relatively narrow space. The reflection member is disposed in front of the first lens group.

[0061] Accordingly, the optical imaging system can be miniaturized while allowing the optical imaging system to have a long focal length.

[0062] In addition, the optical imaging system can further include an image sensor for converting an image of an object into an electrical signal.

[0063] In addition, the optical imaging system can further include an infrared blocking filter (hereinafter referred to as a filter) for blocking infrared rays. The filter can be disposed between the last lens of the optical imaging system and the image sensor.

[0064] In addition, the optical imaging system can further include an aperture disposed between the third lens group and the fourth lens group. For example, the aperture can be disposed in front of the fourth lens group. In an exemplary embodiment, the aperture can be disposed between the sixth lens and the seventh lens.

[0065] In an exemplary embodiment, the first lens group can include a first lens and a second lens, the second lens group can include a third lens and a fourth lens, the third lens group can include a fifth lens and a sixth lens, and the fourth lens group can include a seventh lens, an eighth lens, a ninth lens, and a tenth lens.

[0066] Since the first lens group is disposed at the foremost position of the optical imaging system, waterproofing and dustproofing are easily achieved when the first lens group is fixed.

[0067] The first lens group has a positive refractive power in total, and includes at least one lens having a biconvex shape (i.e., each of an object side surface and an image side surface thereof is convex in a paraxial region thereof).

[0068] In an exemplary embodiment, the first lens group can include two lenses (e.g., a first lens and a second lens).

[0069] The first lens can have a biconvex shape. In addition, the object side surface of the second lens can be concave in a paraxial region thereof. The image side surface of the second lens can be convex or concave in a paraxial region thereof.

[0070] The first lens and the second lens have refractive powers having opposite signs, and a composite focal length of the first lens and the second lens (i.e., a focal length of the first lens group) has a positive value.

[0071] In addition, the first lens and the second lens can be made of materials having different optical characteristics. For example, an Abbe number of the first lens and an Abbe number of the second lens can be different from each other.

[0072] In an exemplary embodiment, an Abbe number of one of the first lens and the second lens can be greater than 50, and an Abbe number of the other lens can be less than 35.

[0073] In exemplary embodiments, the Abbe number of the lens having positive refractive power among the first and second lenses can be greater than 50, and the Abbe number of the lens having negative refractive power among the first and second lenses can be less than 35.

[0074] The second lens group has a negative refractive power in total, and includes at least one lens having a biconcave shape (i.e., each of the object side surface and the image side surface is concave in its paraxial region). In addition, the second lens group can include at least one lens having an Abbe number exceeding 45.

[0075] In exemplary embodiments, the second lens group can include two lenses (e.g., a third lens and a fourth lens). The third lens can have a biconvex shape. Alternatively, the third lens can have a shape in which the object side surface is concave in its paraxial region and the image side surface is convex in its paraxial region. In addition, the fourth lens can have a biconcave shape.

[0076] The third and fourth lenses have refractive powers having opposite signs, and the composite focal length of the third and fourth lenses (i.e., the focal length of the second lens group) is a negative value.

[0077] In addition, the third and fourth lenses can be made of materials having different optical characteristics. For example, the Abbe number of the third lens and the Abbe number of the fourth lens can be different from each other.

[0078] In exemplary embodiments, the Abbe number of one of the third and fourth lenses can be greater than 45, and the Abbe number of the other lens can be less than 21.

[0079] In exemplary embodiments, the Abbe number of the lens having positive refractive power among the third and fourth lenses can be less than 21, and the Abbe number of the lens having negative refractive power among the third and fourth lenses can be greater than 45.

[0080] The third lens group can have a positive refractive power in total, and include at least one lens having a biconvex shape.

[0081] In exemplary embodiments, the third lens group can include two lenses (e.g., a fifth lens and a sixth lens).

[0082] The fifth lens can have a biconvex shape. In addition, the sixth lens can have a shape in which the object side surface is convex in its paraxial region and the image side surface is concave in its paraxial region.

[0083] The fifth and sixth lenses have refractive powers having opposite signs, and the composite focal length of the fifth and sixth lenses (i.e., the focal length of the third lens group) has a positive value.

[0084] In addition, the fifth and sixth lenses can be made of materials having different optical characteristics. For example, the Abbe number of the fifth lens and the Abbe number of the sixth lens can be different from each other.

[0085] In an exemplary embodiment, the Abbe number of one of the fifth and sixth lenses can be greater than 50, and the Abbe number of the other lens can be less than 30.

[0086] In an exemplary embodiment, the Abbe number of the lens having a positive refractive power among the fifth and sixth lenses can be greater than 50, and the Abbe number of the lens having a negative refractive power among the fifth and sixth lenses can be less than 30.

[0087] The fourth lens group includes a plurality of lenses and has a positive refractive power in total.

[0088] The fourth lens group can include at least two lenses having an Abbe number greater than 50.

[0089] In an exemplary embodiment, the fourth lens group includes a seventh lens, an eighth lens, a ninth lens, and a tenth lens.

[0090] The fourth lens group can further include an aperture disposed in front of the seventh lens. Among the plurality of lenses included in the fourth lens group, the lens disposed closest to the aperture (e.g., the seventh lens) can have a positive refractive power.

[0091] Among the lenses included in the fourth lens group, the frontmost lens can have a convex object side surface in a paraxial region thereof, and an Abbe number thereof can be greater than 50.

[0092] Among the lenses included in the fourth lens group, the lens disposed closest to the imaging surface (e.g., the last lens) can have a point of inflection. For example, the tenth lens can have at least one point of inflection on one or both of the object side surface and the image side surface. Alternatively, the lens immediately in front of the last lens (e.g., the ninth lens) can have at least one point of inflection on one or both of the object side surface and the image side surface.

[0093] At least one of the first to fourth lens groups can be moved to change the total focal length of the optical imaging system.

[0094] For example, the distance between the first lens group and the second lens group can be variable. For example, the first lens group can be fixed, and the second lens group can be configured to be movable in the optical axis direction. As the second lens group moves from the object side of the optical imaging system toward the image side of the optical imaging system, the optical imaging system can change from a wide-angle mode to a normal mode, and then to a telephoto mode. In other words, as the second lens group moves in the optical axis direction, the total focal length of the optical imaging system can be changed.

[0095] At least one of the first to fourth lens groups can move to correct a focal position according to a change in a total focal length of the optical imaging system.

[0096] For example, the third lens group can be configured to be movable in the optical axis direction. As the third lens group moves, a distance between the second lens group and the third lens group and a distance between the third lens group and the fourth lens group can be changed.

[0097] For example, when the total focal length of the optical imaging system is changed from a wide angle mode to a normal mode and then to a telephoto mode, the third lens group can move from an image side of the optical imaging system toward an object side of the optical imaging system or move from the object side of the optical imaging system toward the image side of the optical imaging system to correct the focal position.

[0098] The first lens group and the fourth lens group can be fixed.

[0099] Each of the second lens group and the third lens group can include three or less lenses. Since each of the second lens group and the third lens group is movable in the optical axis direction, a driving load can be reduced by limiting the number of lenses included in the second lens group and the third lens group.

[0100] In an exemplary embodiment, the second lens group can move along the optical axis so that a total focal length of the optical imaging system can be changed (for example, an optical zoom function can be implemented), and the third lens group can move along the optical axis to correct a focal position according to a change in the total focal length of the optical imaging system.

[0101] Accordingly, the optical imaging system according to an exemplary embodiment of the disclosure has an optical zoom function.

[0102] The optical imaging system according to an exemplary embodiment of the disclosure has a characteristic of a telephoto lens having a relatively narrow field of view and a long focal length.

[0103] The optical imaging system according to an exemplary embodiment of the disclosure can further include a reflection member having a reflection surface configured to change an optical path of the optical imaging system. For example, the reflection member can be a mirror or a prism.

[0104] The optical path of the optical imaging system can be bent by the reflection member to be elongated in a relatively narrow space.

[0105] The reflection member can be disposed in front of the first lens group. The reflection member can be rotated about two axes to correct a shake during capturing of an image.

[0106] That is, when a shake occurs due to a factor such as a user's hand shake while capturing an image or taking a video, the reflection member can rotate about two axes in response to the shake, thereby compensating for the shake.

[0107] Since the reflection member has a relatively light weight than a weight of the optical imaging system, the shake can be easily compensated for with a small driving force.

[0108] The plurality of lenses of the optical imaging system have aspherical surfaces.

[0109] In the exemplary embodiment, the object side surface and the image side surface of each of the first to tenth lenses can be aspherical.

[0110] The aspherical surface of the lens is defined by the following Equation 1.

[0111]

[0112] In Equation 1, c is a curvature of the lens surface, and is equal to the inverse of the radius of curvature of the lens surface at the optical axis of the lens surface, K is a conic constant, and Y is a distance from any point on the aspherical surface of the lens to the optical axis. Further, the constants A to E are aspherical surface coefficients. Z (also referred to as a sag) is a distance between a point on the aspherical surface of the lens at a distance Y from the optical axis of the aspherical surface and a tangent plane that is perpendicular to the optical axis and intersects the vertex of the aspherical surface, in a direction parallel to the optical axis direction.

[0113] According to the exemplary embodiment of the disclosure, the optical imaging system can satisfy any one or a combination of any two or more of the following conditional expressions 1 to 8:

[0114] 0.95≤Mw / Mt≤1.05 (Conditional Expression 1)

[0115] 0.9≤L14 / L4≤1.2 (Conditional Expression 2)

[0116] 0.8≤D11 / D_last≤1.3 (Conditional Expression 3)

[0117] 0.5≤D41 / (2×IMG HT)≤0.8 (Conditional Expression 4)

[0118] 1.0≤T_dG3 / I_dG3≤1.4 (Conditional Expression 5)

[0119] 1.5≤fG1 / D_last≤2.5 (Conditional Expression 6)

[0120] -0.6≤(R13-R14) / (R13+R14)≤-0.2 (Conditional Expression 7)

[0121] 1.5 ≤ L4 / L4 ≤ 2.2 (Condition Expression 8)

[0122] In an exemplary embodiment, the optical imaging system can satisfy Condition Expression 1: 0.95 ≤ Mw / Mt ≤ 1.05, where Mw is a magnification of the fourth lens group in a wide angle mode when the optical imaging system is focused on an object at infinity, and Mt is a magnification of the fourth lens group in a telephoto mode when the optical imaging system is focused on an object at infinity.

[0123] Condition Expression 1 ensures that a difference between an Fno of the wide angle mode and an Fno of the telephoto mode is not large. The Fno is an F number of the optical imaging system.

[0124] In an exemplary embodiment, the optical imaging system can satisfy Condition Expression 2: 0.9 ≤ L14 / L4 ≤ 1.2, where L14 is a distance between the first lens group and the fourth lens group along an optical axis. For example, L14 is a distance along the optical axis from an image side surface of a lens closest to the second lens group among lenses included in the first lens group to an object side surface of a lens closest to the third lens group among lenses included in the fourth lens group. L4 is a distance along the optical axis from the object side surface of the lens closest to the third lens group among the lenses included in the fourth lens group to an image plane.

[0125] Condition Expression 2 minimizes effective diameters of lenses included in the optical imaging system. In the disclosure, an aperture can be disposed in front of an object side surface of a frontmost lens among lenses included in the fourth lens group. Accordingly, when 0.9 ≤ L14 / L4 ≤ 1.2 is satisfied, the aperture can be disposed approximately at a middle of an optical axis length (also referred to as a total track length) of the optical imaging system, which is a distance along the optical axis from an object side surface of a frontmost lens among lenses included in the first lens group to an image plane. In the disclosure, the lenses included in the optical imaging system have effective diameters that increase as a distance from the aperture increases. Accordingly, the effective diameters of the lenses included in the optical imaging system can be minimized by satisfying 0.9 ≤ L14 / L4 ≤ 1.2. The effective diameter of a lens surface is a diameter of a portion through which light of the lens surface actually passes, and is equal to twice an effective radius of the lens surface. An object side surface of a lens and an image side surface of the lens can have different effective diameters.

[0126] In an exemplary embodiment, the optical imaging system can satisfy Condition Expression 3: 0.8 ≤ D11 / D_last ≤ 1.3, where D11 is an effective diameter of an object side surface of a frontmost lens among lenses included in the first lens group, and D_last is an effective diameter of an image side surface of a rearmost lens among lenses included in the fourth lens group. Condition Expression 3 minimizes effective diameters of lenses included in the optical imaging system.

[0127] In an exemplary embodiment, the optical imaging system can satisfy condition expression 4: 0.5 ≤ D41 / (2 x IMGHT) ≤ 0.8, where D41 is an effective diameter of an object side surface of a frontmost lens among lenses included in the fourth lens group, and IMGHT is half of a diagonal length of an imaging surface.

[0128] Condition expression 4 relates to a diameter of an aperture of the optical imaging system. In the present disclosure, the aperture can be disposed in front of the object side surface of the frontmost lens among the lenses included in the fourth lens group. Accordingly, by satisfying 0.5 ≤ D41 / (2 x IMGHT) ≤ 0.8, the diameter of the aperture can be determined, and a proper Fno can be ensured.

[0129] In an exemplary embodiment, the optical imaging system can satisfy condition expression 5: 1.0 ≤ T_dG3 / I_dG3 ≤ 1.4, where T_dG3 is an amount of movement of the third lens group between a position of the third lens group in a telephoto mode when the optical imaging system is focused on an object at a close focus position (e.g., 500 mm) and a position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at infinity (i.e., an amount of movement of the third lens group during focusing), and I_dG3 is an amount of movement of the third lens group between a position of the third lens group in a wide angle mode when the optical imaging system is focused on an object at infinity and the position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at infinity (i.e., an amount of movement of the third lens group when a field of view of the optical imaging system is changed (i.e., when changed between the wide angle mode and the telephoto mode)). In other words, T_dG3 is a maximum amount of movement of the third lens group in the telephoto mode of the optical imaging system, and I_dG3 is a maximum amount of movement of the third lens group when the optical imaging system is focused on an object at infinity.

[0130] By satisfying 1.0 ≤ T_dG3 / I_dG3 ≤ 1.4, sufficient aberration correction can be achieved while reducing a size of the optical imaging system.

[0131] In an exemplary embodiment, the optical imaging system can satisfy condition expression 6: 1.5 ≤ fG1 / D_last ≤ 2.5, where fG1 is a focal length of the first lens group.

[0132] By satisfying 1.5 ≤ fG1 / D_last ≤ 2.5, the optical imaging system can capture a bright image while reducing a size of the optical imaging system.

[0133] In an exemplary embodiment, the optical imaging system can satisfy a conditional expression 7: -0.6 ≤ (R13-R14) / (R13+R14) ≤ -0.2, where R13 is a radius of curvature of an object side surface of a frontmost lens included in the fourth lens group, and R14 is a radius of curvature of an image side surface of the frontmost lens included in the fourth lens group.

[0134] The frontmost lens in the fourth lens group is a lens disposed closest to the stop. Accordingly, the spherical aberration can be appropriately corrected by satisfying -0.6 ≤ (R13-R14) / (R13+R14) ≤ -0.2.

[0135] In an exemplary embodiment, the optical imaging system can satisfy a conditional expression 8: 1.5 ≤ ft / L4 ≤ 2.2, where ft is a total focal length of the optical imaging system in a telephoto mode when the optical imaging system is focused on an object at infinity.

[0136] A suitable zoom ratio can be determined by satisfying 1.5 ≤ ft / L4 ≤ 2.2.

[0137] Figure 1 FIG. 1 is a view illustrating a wide-angle mode of an optical imaging system according to a first embodiment of the present disclosure, and Figure 2 FIG. 2 is a view illustrating a telephoto mode of the optical imaging system according to the first embodiment of the present disclosure.

[0138] An optical imaging system according to a first embodiment of the present disclosure will be described with reference to Figure 1 and Figure 2 FIGS. 1 and 2.

[0139] The optical imaging system according to the first embodiment of the present disclosure includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4. In addition, the optical imaging system includes a reflecting member P disposed in front of the first lens group G1.

[0140] In order from an object side of the optical imaging system, the first lens group G1 includes a first lens 101 and a second lens 102, the second lens group G2 includes a third lens 103 and a fourth lens 104, the third lens group G3 can include a fifth lens 105 and a sixth lens 106, and the fourth lens group G4 includes a seventh lens 107, an eighth lens 108, a ninth lens 109, and a tenth lens 110.

[0141] A stop Stop can be disposed in front of the seventh lens 107, which is a frontmost lens in the fourth lens group G4. A distance between the stop Stop and an apex of an object side surface of the seventh lens 107 along an optical axis can be 0.

[0142] Additionally, the optical imaging system may also include a filter 111 and an image sensor (not shown).

[0143] The optical imaging system according to the first embodiment of this disclosure can focus an image of an object onto an imaging surface 112. The imaging surface 112 can be a surface on which the optical imaging system focuses the image. For example, the imaging surface 112 can be a light-receiving surface of an image sensor.

[0144] In a first embodiment of this disclosure, the reflecting member P may be a prism, but alternatively it may be a mirror.

[0145] At least one of the first to fourth lens groups can be moved to change the total focal length of the optical imaging system. For example, the first lens group G1 and the fourth lens group G4 can be fixed, and the second lens group G2 can be moved along the optical axis to change the total focal length of the optical imaging system. That is, as the second lens group G2 moves from the object side of the optical imaging system toward the image side of the optical imaging system, the total focal length of the optical imaging system can be changed.

[0146] Furthermore, at least one of the first lens group G1 to the fourth lens group G4 can be moved to correct the focal position according to changes in the total focal length of the optical imaging system. For example, when the total focal length of the optical imaging system is changed by moving the second lens group G2, the third lens group G3 can be moved along the optical axis to correct the focal position.

[0147] The characteristics of each lens in the optical imaging system according to the first embodiment of this disclosure (e.g., radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number, effective radius, and focal length) are shown in Table 1 below. An asterisk (*) indicates that the lens surface is an aspherical lens surface.

[0148] Table 1

[0149]

[0150]

[0151] Table 2 below shows the various characteristics of the optical imaging system according to the first embodiment of the present disclosure for objects at infinity in wide-angle mode, normal mode and telephoto mode, and for objects at the near-focal position of the optical imaging system in wide-angle mode, normal mode and telephoto mode, the near-focal position being the closest position of the object on the imaging plane 112 where the optical imaging system can focus the image of the object.

[0152] Table 2

[0153]

[0154]

[0155] In Table 2, D0 is the object distance, D1 is the distance between the second lens 102 and the third lens 103 along the optical axis, D2 is the distance between the fourth lens 104 and the fifth lens 105 along the optical axis, and D3 is the distance between the sixth lens 106 and the seventh lens 107 along the optical axis.

[0156] f is the total focal length of the optical imaging system, MAG is the magnification of the optical imaging system, HFOV is half of the field of view of the optical imaging system, Fno is the F number of the optical imaging system, and OAL is the optical axis length of the optical imaging system, i.e., the distance along the optical axis from the object side surface of the first lens 101 to the imaging surface 112. The OAL is also referred to as the total track length (TTL).

[0157] In the first embodiment of the present disclosure, the first lens group G1 has a positive refractive power in total, the second lens group G2 has a negative refractive power in total, the third lens group G3 has a positive refractive power in total, and the fourth lens group G4 has a positive refractive power in total.

[0158] The first lens 101 has a positive refractive power, and the object side surface and the image side surface of the first lens 101 are convex in their paraxial regions.

[0159] The second lens 102 has a negative refractive power, the object side surface of the second lens 102 is concave in its paraxial region, and the image side surface of the second lens 102 is convex in its paraxial region.

[0160] The third lens 103 has a positive refractive power, and the object side surface and the image side surface of the third lens 103 are convex in their paraxial regions.

[0161] The fourth lens 104 has a negative refractive power, and the object side surface and the image side surface of the fourth lens 104 are concave in their paraxial regions.

[0162] The fifth lens 105 has a positive refractive power, and the object side surface and the image side surface of the fifth lens 105 are convex in their paraxial regions.

[0163] The sixth lens 106 has a negative refractive power, the object side surface of the sixth lens 106 is convex in its paraxial region, and the image side surface of the sixth lens 106 is concave in its paraxial region.

[0164] The seventh lens 107 has a positive refractive power, the object side surface of the seventh lens 107 is convex in its paraxial region, and the image side surface of the seventh lens 107 is concave in its paraxial region. The stop can be disposed in front of the object side surface of the seventh lens 107.

[0165] The eighth lens 108 has a negative refractive power, the object side surface of the eighth lens 108 is convex in its paraxial region, and the image side surface of the eighth lens 108 is concave in its paraxial region.

[0166] The ninth lens 109 has a negative refractive power, and the object side surface and the image side surface of the ninth lens 109 are concave in their paraxial regions.

[0167] The tenth lens 110 has a positive refractive power, the object side surface of the tenth lens 110 is convex in its paraxial region, and the image side surface of the tenth lens 110 is concave in its paraxial region.

[0168] The tenth lens 110 can have at least one inflection point on one or both of the object side surface and the image side surface.

[0169] Each surface of the first lens 101 to the tenth lens 110 has aspherical coefficients as shown in Table 3 below. For example, the object side surface and the image side surface of each of the first lens 101 to the tenth lens 110 are aspherical.

[0170] Table 3

[0171]

[0172]

[0173] Figure 3 is a view showing a wide-angle mode of the optical imaging system according to the second embodiment of the present disclosure, and Figure 4 is a view showing a telephoto mode of the optical imaging system according to the second embodiment of the present disclosure.

[0174] The optical imaging system according to the second embodiment of the present disclosure will be described with reference to Figure 3 and Figure 4 The optical imaging system according to the second embodiment of the present disclosure will be described with reference to

[0175] The optical imaging system according to the second embodiment of the present disclosure includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4. In addition, the optical imaging system can include a reflection member P disposed in front of the first lens group G1.

[0176] In order from the object side of the optical imaging system, the first lens group G1 can include a first lens 201 and a second lens 202, the second lens group G2 can include a third lens 203 and a fourth lens 204, the third lens group G3 can include a fifth lens 205 and a sixth lens 206, and the fourth lens group G4 can include a seventh lens 207, an eighth lens 208, a ninth lens 209, and a tenth lens 210.

[0177] A stop can be disposed in front of the seventh lens 207, which is the foremost lens in the fourth lens group G4. The distance between the stop and the vertex of the object side surface of the seventh lens 207 along the optical axis can be 0.

[0178] In addition, the optical imaging system can further include a filter 211 and an image sensor (not shown).

[0179] The optical imaging system according to the second embodiment of the present disclosure can focus an image of an object on the imaging surface 212. The imaging surface 212 can be a surface on which the optical imaging system focuses an image. For example, the imaging surface 212 can be one surface of an image sensor on which light is received.

[0180] In the second embodiment of the present disclosure, the reflection member P can be a prism, but can alternatively be a mirror.

[0181] At least one lens group among the first lens group G1 to the fourth lens group G4 can move to change the total focal length of the optical imaging system. For example, the first lens group G1 and the fourth lens group G4 can be fixed, and the second lens group G2 can move along the optical axis to change the total focal length of the optical imaging system. That is, as the second lens group G2 moves from the object side of the optical imaging system toward the image side of the optical imaging system, the total focal length of the optical imaging system can be changed.

[0182] In addition, at least one lens group among the first lens group G1 to the fourth lens group G4 can move to correct the focal position according to a change in the total focal length of the optical imaging system. For example, when the total focal length of the optical imaging system is changed by moving the second lens group G2, the third lens group G3 can move along the optical axis to correct the focal position.

[0183] The characteristics (e.g., the radius of curvature, the thickness of a lens or the distance between lenses, the refractive index, the Abbe number, the effective radius, and the focal length) of each lens of the optical imaging system according to the second embodiment of the present disclosure are shown in Table 4 below. An asterisk of the lens surface number indicates that the lens surface is an aspherical lens surface.

[0184] Table 4

[0185]

[0186] Table 5 below shows various characteristics of the optical imaging system according to the second embodiment of the present disclosure for an object at infinity in the wide-angle mode, the normal mode, and the telephoto mode, and for an object at the close-up position of the optical imaging system, i.e., the closest position of the object at which the optical imaging system can focus an image of the object on the imaging surface 212, in the wide-angle mode, the normal mode, and the telephoto mode.

[0187] Table 5

[0188]

[0189] In Table 5, D0 is the object distance, D1 is the distance between the second lens 202 and the third lens 203 along the optical axis, D2 is the distance between the fourth lens 204 and the fifth lens 205 along the optical axis, and D3 is the distance between the sixth lens 206 and the seventh lens 207 along the optical axis.

[0190] f is the total focal length of the optical imaging system, MAG is the magnification of the optical imaging system, HFOV is half of the field of view of the optical imaging system, Fno is the F number of the optical imaging system, and OAL is the optical axis length of the optical imaging system, i.e., the distance along the optical axis from the object side surface of the first lens 201 to the imaging surface 212. The OAL is also referred to as the total track length (TTL).

[0191] In the second embodiment of the present disclosure, the first lens group G1 has a positive refractive power in total, the second lens group G2 has a negative refractive power in total, the third lens group G3 has a positive refractive power in total, and the fourth lens group G4 has a positive refractive power in total.

[0192] The first lens 201 has a positive refractive power, and the object side surface and the image side surface of the first lens 201 are convex in their paraxial regions.

[0193] The second lens 202 has a negative refractive power, and the object side surface and the image side surface of the second lens 202 are concave in their paraxial regions.

[0194] The third lens 203 has a positive refractive power, and the object side surface and the image side surface of the third lens 203 are convex in their paraxial regions.

[0195] The fourth lens 204 has a negative refractive power, and the object side surface and the image side surface of the fourth lens 204 are concave in their paraxial regions.

[0196] The fifth lens 205 has a positive refractive power, and the object side surface and the image side surface of the fifth lens 205 are convex in their paraxial regions.

[0197] The sixth lens 206 has a negative refractive power, the object side surface of the sixth lens 206 is convex in its paraxial region, and the image side surface of the sixth lens 206 is concave in its paraxial region.

[0198] The seventh lens 207 has a positive refractive power, the object side surface of the seventh lens 207 is convex in its paraxial region, and the image side surface of the seventh lens 207 is concave in its paraxial region. The stop can be disposed in front of the object side surface of the seventh lens 207.

[0199] The eighth lens 208 has a negative refractive power, the object side surface of the eighth lens 208 is convex in its paraxial region, and the image side surface of the eighth lens 208 is concave in its paraxial region.

[0200] The ninth lens 209 has a negative refractive power, the object side surface of the ninth lens 209 is concave in its paraxial region, and the image side surface of the ninth lens 209 is convex in its paraxial region.

[0201] The tenth lens 210 has a negative refractive power, the object side surface of the tenth lens 210 is convex in its paraxial region, and the image side surface of the tenth lens 210 is concave in its paraxial region.

[0202] The tenth lens 210 can have at least one inflection point on one or both of the object side surface and the image side surface.

[0203] Each surface of the first lens 201 to the tenth lens 210 has an aspheric coefficient as shown in Table 6 below. For example, the object side surface and the image side surface of each of the first lens 201 to the tenth lens 210 are aspheric.

[0204] Table 6

[0205]

[0206]

[0207] Figure 5 is a view showing a wide-angle mode of the optical imaging system according to the third embodiment of the present disclosure, and Figure 6 is a view showing a telephoto mode of the optical imaging system according to the third embodiment of the present disclosure.

[0208] The optical imaging system according to the third embodiment of the present disclosure will be described with reference to Figure 5 and Figure 6 The optical imaging system according to the third embodiment of the present disclosure will be described with reference to

[0209] The optical imaging system according to the third embodiment of the present disclosure includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4. In addition, the optical imaging system can include a reflection member P disposed in front of the first lens group G1.

[0210] In order from the object side of the optical imaging system, the first lens group G1 can include a first lens 301 and a second lens 302, the second lens group G2 can include a third lens 303 and a fourth lens 304, the third lens group G3 can include a fifth lens 305 and a sixth lens 306, and the fourth lens group G4 can include a seventh lens 307, an eighth lens 308, a ninth lens 309, and a tenth lens 310.

[0211] A stop can be disposed in front of the seventh lens 307, which is the foremost lens in the fourth lens group G4. The distance between the stop and the vertex of the object side surface of the seventh lens 307 along the optical axis can be 0.

[0212] In addition, the optical imaging system can further include a filter 311 and an image sensor (not shown).

[0213] The optical imaging system according to the third embodiment of the present disclosure can focus an image of an object on an imaging surface 312. The imaging surface 312 can be a surface on which an image is focused by the optical imaging system. For example, the imaging surface 312 can be one surface on which light is received by an image sensor.

[0214] In the third embodiment of the present disclosure, the reflecting member P can be a prism, but can alternatively be a mirror.

[0215] At least one lens group among the first lens group G1 to the fourth lens group G4 can move to change the total focal length of the optical imaging system. For example, the first lens group G1 and the fourth lens group G4 can be fixed, and the second lens group G2 can move along the optical axis to change the total focal length of the optical imaging system. That is, as the second lens group G2 moves from the object side of the optical imaging system toward the image side of the optical imaging system, the total focal length of the optical imaging system can be changed.

[0216] In addition, at least one lens group among the first lens group G1 to the fourth lens group G4 can move to correct the focal position according to a change in the total focal length of the optical imaging system. For example, when the total focal length of the optical imaging system is changed by moving the second lens group G2, the third lens group G3 can move along the optical axis to correct the focal position.

[0217] The characteristics (e.g., the radius of curvature, the thickness of a lens or the distance between lenses, the refractive index, the Abbe number, the effective radius, and the focal length) of each lens of the optical imaging system according to the third embodiment of the present disclosure are shown in Table 7 below. An asterisk of the lens surface number indicates that the lens surface is an aspherical lens surface.

[0218] Table 7

[0219]

[0220]

[0221] Table 8 below shows various characteristics of the optical imaging system according to the third embodiment of the present disclosure for an object at infinity in the wide-angle mode, the normal mode, and the telephoto mode, and for an object at the closest position of the optical imaging system, i.e., the closest position of the object at which the optical imaging system can focus an image of the object on the imaging surface 312, in the wide-angle mode, the normal mode, and the telephoto mode.

[0222] Table 8

[0223]

[0224] In Table 8, D0 is the object distance, D1 is the distance between the second lens 302 and the third lens 303 along the optical axis, D2 is the distance between the fourth lens 304 and the fifth lens 305 along the optical axis, and D3 is the distance between the sixth lens 306 and the seventh lens 307 along the optical axis.

[0225] f is the total focal length of the optical imaging system, MAG is the magnification of the optical imaging system, HFOV is half of the field of view of the optical imaging system, Fno is the F-number of the optical imaging system, and OAL is the optical axis length of the optical imaging system, i.e., the distance along the optical axis from the object side surface of the first lens 301 to the imaging surface 312. The OAL is also referred to as the total track length (TTL).

[0226] In the third embodiment of the present disclosure, the first lens group G1 has a positive refractive power in total, the second lens group G2 has a negative refractive power in total, the third lens group G3 has a positive refractive power in total, and the fourth lens group G4 has a positive refractive power in total.

[0227] The first lens 301 has a positive refractive power, and the object side surface and the image side surface of the first lens 301 are convex in their paraxial regions.

[0228] The second lens 302 has a negative refractive power, the object side surface of the second lens 302 is concave in its paraxial region, and the image side surface of the second lens 302 is convex in its paraxial region.

[0229] The third lens 303 has a positive refractive power, the object side surface of the third lens 303 is concave in its paraxial region, and the image side surface of the third lens 303 is convex in its paraxial region.

[0230] The fourth lens 304 has a negative refractive power, and the object side surface and the image side surface of the fourth lens 304 are concave in their paraxial regions.

[0231] The fifth lens 305 has a positive refractive power, and the object side surface and the image side surface of the fifth lens 305 are convex in their paraxial regions.

[0232] The sixth lens 306 has a negative refractive power, the object side surface of the sixth lens 306 is convex in its paraxial region, and the image side surface of the sixth lens 306 is concave in its paraxial region.

[0233] The seventh lens 307 has a positive refractive power, the object side surface of the seventh lens 307 is convex in its paraxial region, and the image side surface of the seventh lens 307 is concave in its paraxial region. A stop can be disposed in front of the object side surface of the seventh lens 307.

[0234] The eighth lens 308 has a negative refractive power, the object side surface of the eighth lens 308 is convex in its paraxial region, and the image side surface of the eighth lens 308 is concave in its paraxial region.

[0235] The ninth lens 309 has a negative refractive power, and the object side surface and the image side surface of the ninth lens 309 are concave in their paraxial regions.

[0236] The ninth lens 309 can have at least one inflection point on one or both of the object side surface and the image side surface.

[0237] The tenth lens 310 has a positive refractive power, the object side surface of the tenth lens 310 is convex in its paraxial region, and the image side surface of the tenth lens 310 is concave in its paraxial region.

[0238] Each surface of the first lens 301 to the tenth lens 310 has an aspheric coefficient as shown in Table 9 below. For example, the object side surface and the image side surface of each of the first lens 301 to the tenth lens 310 are aspheric.

[0239] Table 9

[0240]

[0241] Table 10 below shows the values of the quantities Mw, Mt, L14, L4, D11, D41, 2 x IMG HT, D_last, T_dG3, I_dG3, fG1, R13, R14, and ft, and the focal length (fG2) of the second lens group G2, the focal length (fG3) of the third lens group G3, and the focal length (fG4) of the fourth lens group G4 in the conditional expressions 1 to 8 of the first embodiment, the second embodiment, and the third embodiment of the optical imaging system according to the present disclosure.

[0242] Table 10

[0243] amount Embodiment 1 Embodiment 2 Embodiment 3 Mw 0.241697078 0.413969246 0.271739823 Mt 0.240884695 0.413255436 0.270926915 L14 11.841 13.573 12.677 L4 10.934 14.234 10.818 D11 10 10.8 9.2 D41 5.32 6.4 5.1 2xIMG HT 7.2 11.4 7.2 D_last 8.084 12.052 7.896 T_dG3 1.784093 2.017658 1.475590 I_dG3 1.503846 1.541631 1.327329 fG1 19.460104 20.220155 17.682005 fG2 -7.60266 -7.92345 -7.27064 fG3 13.65687 13.53069 12.57085 fG4 15.19574 48.00535 16.06743 R13 3.853 4.913 4.438 R14 11.678 8.906 14.303 ft 19.172097 28.474176 19.121632

[0244] Table 11 below shows values of conditional expressions 1 to 8 calculated based on the values of Mw, Mt, L14, L4, D11, D41, 2xIMG HT, D_last, T_dG3, I_dG3, fG1, R13, R14, and ft in Table 10 above for the first, second, and third embodiments of the optical imaging system according to the present disclosure.

[0245] Table 11

[0246]

[0247] While the present disclosure includes specific examples, it will be apparent to one skilled in the art, after an understanding of the disclosure herein, that various changes in form and details can be made therein without departing from the spirit and scope of the claims and their equivalents. The description of features or aspects in each example is considered applicable to analogous features or aspects in other examples. Suitable results can be achieved if the described techniques are performed in a different order, and / or if the components of the described systems, architectures, devices, or circuits are combined in a different manner, and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of the present disclosure is not limited to the specific embodiments described herein, but only by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims

1. An optical imaging system characterized by, comprises: a first lens group, a second lens group, a third lens group, and a fourth lens group, which are sequentially arranged from an object side of the optical imaging system toward an imaging plane of the optical imaging system along an optical axis of the optical imaging system and each include a plurality of lenses, wherein each of the first lens group and the fourth lens group has a positive refractive power in total, the optical imaging system further comprises a diaphragm arranged between the third lens group and the fourth lens group, the first lens group, the diaphragm, and the fourth lens group are arranged at fixed positions on the optical axis, and the second lens group and the third lens group are configured to be movable along the optical axis, the optical imaging system further comprises a reflecting member arranged in front of the first lens group, the reflecting member including a reflecting surface configured to change an optical path of the optical imaging system, and the fourth lens group is a lens group arranged closest to the imaging plane.

2. The optical imaging system of claim 1, wherein, 0.95 ≤ Mw / Mt ≤ 1.05 is satisfied, where Mw is a magnification of the fourth lens group in a wide-angle mode of the optical imaging system when the optical imaging system is focused on an object at infinity, and Mt is a magnification of the fourth lens group in a telephoto mode of the optical imaging system when the optical imaging system is focused on an object at infinity.

3. The optical imaging system of claim 1, wherein, 0.9 ≤ L14 / L4 ≤ 1.2 is satisfied, where L14 is a distance along the optical axis from an image side surface of a lens included in the first lens group and arranged closest to the second lens group to an object side surface of a lens included in the fourth lens group and arranged closest to the third lens group, and L4 is a distance along the optical axis from the object side surface of the lens included in the fourth lens group and arranged closest to the third lens group to the imaging plane.

4. The optical imaging system of claim 1, wherein, 0.8 ≤ D11 / D_last ≤ 1.3 is satisfied, where D11 is an effective diameter of an object side surface of a lens included in the first lens group and arranged closest to the reflecting member, and D_last is an effective diameter of an image side surface of a lens included in the fourth lens group and arranged closest to the imaging plane.

5. The optical imaging system of claim 1, wherein, 0.5 ≤ D41 / (2 × IMG HT) ≤ 0.8 is satisfied, where D41 is an effective diameter of an object side surface of a lens included in the fourth lens group and arranged closest to the third lens group, and IMG HT is half of a diagonal length of the imaging plane.

6. The optical imaging system of claim 1, wherein, 1.0 ≤ T_dG3 / I_dG3 ≤ 1.4 is satisfied, where T_dG3 is a maximum movement amount of the third lens group in a telephoto mode of the optical imaging system, and I_dG3 is a maximum movement amount of the third lens group when the optical imaging system is focused on an object at infinity.

7. The optical imaging system of claim 1, wherein, 1.5 ≤ fG1 / D_last ≤ 2.5 is satisfied, where fG1 is a focal length of the first lens group, and D_last is an effective diameter of an image side surface of a lens included in the fourth lens group and arranged closest to the imaging plane.

8. The optical imaging system of claim 1, wherein, -0.6 ≤ (R13 - R14) / (R13 + R14) ≤ -0.2 is satisfied, where R13 is a radius of curvature of an object side surface of a lens closest to the third lens group among the lenses included in the fourth lens group, and R14 is a radius of curvature of an image side surface of a lens closest to the third lens group among the lenses included in the fourth lens group.

9. The optical imaging system of claim 1, wherein, 1.5 ≤ ft / L4 ≤ 2.2 is satisfied, where ft is a total focal length of the optical imaging system in a telephoto mode of the optical imaging system when the optical imaging system is focused on an object at infinity, and L4 is a distance from an object side surface of a lens closest to the third lens group among the lenses included in the fourth lens group to the image plane along the optical axis.

10. The optical imaging system of claim 1, wherein, The second lens group has a negative refractive power, and the third lens group has a positive refractive power.

11. The optical imaging system of claim 1, wherein, The first lens group includes a first lens and a second lens, The first lens and the second lens have refractive powers having opposite signs, and In the first lens and the second lens, an Abbe number of the lens having a positive refractive power is greater than 50, and an Abbe number of the lens having a negative refractive power is less than 35.

12. The optical imaging system of claim 1, wherein, The second lens group includes a third lens and a fourth lens, The third lens and the fourth lens have refractive powers having opposite signs, and In the third lens and the fourth lens, an Abbe number of the lens having a positive refractive power is less than 21, and an Abbe number of the lens having a negative refractive power is greater than 45.

13. The optical imaging system of claim 1, wherein, The third lens group includes a fifth lens and a sixth lens, The fifth lens and the sixth lens have refractive powers having opposite signs, and In the fifth lens and the sixth lens, an Abbe number of the lens having a positive refractive power is greater than 50, and an Abbe number of the lens having a negative refractive power is less than 30.

14. The optical imaging system of claim 1, wherein, The fourth lens group includes a seventh lens, an eighth lens, a ninth lens, and a tenth lens, and The seventh lens has an object side surface convex in a paraxial region thereof and an Abbe number greater than 50.

15. The optical imaging system of claim 14, wherein, The stop is disposed in front of the seventh lens, and The seventh lens has a positive refractive power.

16. The optical imaging system of claim 14, wherein, The ninth lens or the tenth lens has at least one inflection point on one or both of an object side surface and an image side surface thereof.

17. An optical imaging system characterized by, comprises: a first lens group, a second lens group, a third lens group, and a fourth lens group, which are disposed in order from an object side of the optical imaging system toward an image plane of the optical imaging system along an optical axis of the optical imaging system, and each of which includes a plurality of lenses; and a stop, which is disposed between the third lens group and the fourth lens group, wherein each of the first lens group and the fourth lens group has a positive refractive power in total and is disposed at a fixed position on the optical axis, the second lens group is configured to be movable along the optical axis to adjust a focal length of the optical imaging system between a wide-angle mode of the optical imaging system and a telephoto mode of the optical imaging system, the third lens group is configured to be movable along the optical axis to adjust a focal position of the optical imaging system when the second lens group is moved along the optical axis to adjust the focal length of the optical imaging system, and satisfies 0.95≤Mw / Mt≤1.05, where Mw is a magnification of the fourth lens group in the wide-angle mode when the optical imaging system is focused on an object at infinity, and Mt is a magnification of the fourth lens group in the telephoto mode when the optical imaging system is focused on an object at infinity.

18. The optical imaging system of claim 17, wherein, satisfies 1.0≤T_dG3 / I_dG3≤1.4, where T_dG3 is an amount of movement of the third lens group between a position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at a close focus position and a position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at infinity, and I_dG3 is an amount of movement of the third lens group between a position of the third lens group in the wide-angle mode when the optical imaging system is focused on an object at infinity and a position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at infinity.

19. The optical imaging system of claim 17, wherein, the second lens group has a negative refractive power in total, and the third lens group has a positive refractive power in total.

20. The optical imaging system of claim 17, wherein, the stop is aligned with a vertex of an object side surface of a lens disposed closest to the third lens group among lenses included in the fourth lens group. the third lens group is configured to be movable along the optical axis to adjust a focal position of the optical imaging system when the second lens group is moved along the optical axis to adjust the focal length of the optical imaging system, and satisfies 0.95≤Mw / Mt≤1.05, where Mw is a magnification of the fourth lens group in the wide-angle mode when the optical imaging system is focused on an object at infinity, and Mt is a magnification of the fourth lens group in the telephoto mode when the optical imaging system is focused on an object at infinity. satisfies 1.0≤T_dG3 / I_dG3≤1.4, where T_dG3 is an amount of movement of the third lens group between a position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at a close focus position and a position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at infinity, and I_dG3 is an amount of movement of the third lens group between a position of the third lens group in the wide-angle mode when the optical imaging system is focused on an object at infinity and a position of the third lens group in the telephoto mode when the optical imaging system is focused on an object at infinity. the second lens group has a negative refractive power in total, and the third lens group has a positive refractive power in total. the stop is aligned with a vertex of an object side surface of a lens disposed closest to the third lens group among lenses included in the fourth lens group.

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