Optical image capturing system

Abstract

The optical imaging system comprises a first lens group, a second lens group, a third lens group and a fourth lens group which are sequentially arranged from the object side of the optical imaging system to the imaging surface of the optical imaging system along the optical axis of the optical imaging system; and a reflective member disposed between the first lens group and the second lens group, in which the second lens group and the fourth lens group are each configured to be movable along an optical axis, the first lens group having a positive refractive power, and the optical imaging system satisfying a conditional expression-3.5 lt; fG1 / fG2lt, fG1 / fG2lt; fG1 is the focal length of the first lens group, and fG2 is the focal length of the second lens group.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of priority of Korean Patent Application No. 10 - 2024 - 0099987, filed on July 29, 2024 with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. Technical field

[0003] The present disclosure relates to an optical imaging system. Background art

[0004] Camera modules have become a standard feature in portable electronic devices including smart phones.

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

[0006] However, this method requires multiple camera modules for the optical zoom effect, and due to the difference in the field of view between the multiple camera modules, image processing needs to be performed via software rather than optical zoom when imaging at an intermediate magnification, thus reducing the image quality. Summary of the utility model

[0007] The provision of this Summary of the utility model section aims to introduce, in a brief form, a selection of concepts, which will be further described in the Detailed implementation section below. This Summary of the utility model section is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to assist in determining 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 in sequence 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 a reflection member disposed between the first lens group and the second lens group, wherein the second lens group and the fourth lens group are each configured to be movable along the optical axis, the first lens group has a positive refractive power, and the optical imaging system satisfies the conditional expression - 3.5 < fG1 / fG2 < - 2, where fG1 is the focal length of the first lens group and fG2 is the focal length of the second lens group.

[0009] The first lens group may include a first lens and a second lens arranged in sequence along the optical axis from the object side of the first lens group toward the imaging surface, and the Abbe number of one of the first lens and the second lens may be 50 or greater, and the Abbe number of the other of the first lens and the second lens may be 25 or less.

[0010] The first lens and the second lens may have refractive powers of opposite signs, and among the first lens and the second lens, the lens having an Abbe number of 50 or more may have a positive refractive power, and the lens having an Abbe number of 25 or less may have a negative refractive power.

[0011] The optical imaging system may satisfy the conditional expression 0.1 < air_T12 < 2.5, where air_T12 is the distance along the optical axis from the image side surface of the first lens to the object side surface of the second lens.

[0012] The optical imaging system may satisfy the conditional expression 0.1 < fw / f2 < 2.0, where fw is the total focal length of the optical imaging system in the wide-angle mode, and f2 is the focal length of the second lens.

[0013] The second lens group may have a negative refractive power and may include a plurality of lenses, and one of the plurality of lenses of the second lens group may have a biconcave shape.

[0014] The optical imaging system may satisfy the conditional expression 0.6 < fc / fG2 < 1.0, where fc is the focal length of the lens having a biconcave shape among the plurality of lenses of the second lens group.

[0015] The second lens group may include a third lens, a fourth lens, and a fifth lens arranged in order along the optical axis from the object side of the second lens group toward the imaging surface, and the optical imaging system may satisfy the conditional expression 0.1 < air_T45 < 1.0, where air_T45 is the distance along the optical axis from the image side surface of the fourth lens to the object side surface of the fifth lens.

[0016] The optical imaging system may satisfy the conditional expression 0.1 < fw / f5 < 2.0, where fw is the total focal length of the optical imaging system in the wide-angle mode, and f5 is the focal length of the fifth lens.

[0017] The first lens group may include a first lens and a second lens arranged in order along the optical axis from the object side of the first lens group toward the imaging surface, the second lens group may include a third lens, a fourth lens, and a fifth lens arranged in order along the optical axis from the object side of the second lens group toward the imaging surface, and the optical imaging system may satisfy the conditional expressions 0.1 < n1 - n2 < 0.2 and 0.08 < n5 - n4 < 0.2, where n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n4 is the refractive index of the fourth lens, and n5 is the refractive index of the fifth lens.

[0018] Each of the third lens group and the fourth lens group may have a positive refractive power.

[0019] The optical imaging system may further include an aperture disposed between the second lens group and the third lens group. The third lens group may include a plurality of lenses, and among the plurality of lenses of the third lens group, the lens closest to the aperture may have a positive refractive power.

[0020] The optical imaging system may satisfy the conditional expression 0.4 < DS / TTL < 0.65, where DS is the distance along the optical axis from the object side surface of the first lens group to the aperture, and TTL is the distance along the optical axis from the object side surface of the first lens group to the imaging surface.

[0021] The optical imaging system may satisfy the conditional expression 0.45 < DS / fG1 < 1.0, where DS is the distance along the optical axis from the object side surface of the first lens group to the aperture.

[0022] The optical imaging system may satisfy the conditional expression -0.6 < fG2 / fG3 < -0.2, where fG3 is the focal length of the third lens group.

[0023] The first lens group may include a first lens and a second lens arranged in sequence along the optical axis from the object side of the first lens group toward the imaging surface. The second lens group may include a third lens, a fourth lens, and a fifth lens arranged in sequence along the optical axis from the object side of the second lens group toward the imaging surface. The third lens group may include a sixth lens and a seventh lens arranged in sequence along the optical axis from the object side of the third lens group toward the imaging surface. The fourth lens group may include an eighth lens, and the optical imaging system may satisfy the conditional expression -0.9 < L8sag_1 - L8sag_1 /

[0024] Other features and aspects will be obvious from the accompanying drawings and the following detailed description. Description of the Drawings

[0025] Figure 1A is a diagram showing the wide-angle mode of the optical imaging system according to the first embodiment in the present disclosure.

[0026] Figure 1B is a diagram showing the telephoto mode of the optical imaging system according to the first embodiment in the present disclosure.

[0027] Figure 2A is a diagram showing Figure 1A the aberration characteristics of the optical imaging system shown in

[0028] Figure 2B is a diagram showing Figure 1BThe diagram shows the aberration characteristics of the optical imaging system.

[0029] Figure 3A This is a diagram showing a wide-angle mode of an optical imaging system according to a second embodiment of the present disclosure.

[0030] Figure 3B This is a diagram showing the telephoto mode of an optical imaging system according to a second embodiment of the present disclosure.

[0031] Figure 4A It is shown Figure 3A The diagram shows the aberration characteristics of the optical imaging system.

[0032] Figure 4B It is shown Figure 3B The diagram shows the aberration characteristics of the optical imaging system.

[0033] Figure 5A This is a diagram showing a wide-angle mode of an optical imaging system according to a third embodiment of the present disclosure.

[0034] Figure 5B This is a diagram showing the telephoto mode of an optical imaging system according to a third embodiment of this disclosure.

[0035] Figure 6A It is shown Figure 5A The diagram shows the aberration characteristics of the optical imaging system.

[0036] Figure 6B It is shown Figure 5B The diagram shows the aberration characteristics of the optical imaging system.

[0037] Figure 7A This is a diagram showing a wide-angle mode of an optical imaging system according to a fourth embodiment of the present disclosure.

[0038] Figure 7B This is a diagram showing the telephoto mode of an optical imaging system according to the fourth embodiment of this disclosure.

[0039] Figure 8A It is shown Figure 7A The diagram shows the aberration characteristics of the optical imaging system.

[0040] Figure 8B It is shown Figure 7B The diagram shows the aberration characteristics of the optical imaging system.

[0041] Figure 9A This is a diagram showing a wide-angle mode of an optical imaging system according to a fifth embodiment of the present disclosure.

[0042] Figure 9BThis is a diagram showing the telephoto mode of an optical imaging system according to the fifth embodiment of this disclosure.

[0043] Figure 10A It is shown Figure 9A The diagram shows the aberration characteristics of the optical imaging system.

[0044] Figure 10B It is shown Figure 9B The diagram shows the aberration characteristics of the optical imaging system.

[0045] Figure 11A This is a diagram showing a wide-angle mode of an optical imaging system according to a sixth embodiment of the present disclosure.

[0046] Figure 11B This is a diagram showing the telephoto mode of an optical imaging system according to a sixth embodiment of this disclosure.

[0047] Figure 12A It is shown Figure 11A The diagram shows the aberration characteristics of the optical imaging system.

[0048] Figure 12B It is shown Figure 11B The diagram shows the aberration characteristics of the optical imaging system.

[0049] Figure 13A This is a diagram showing a wide-angle mode of an optical imaging system according to a seventh embodiment of the present disclosure.

[0050] Figure 13B This is a diagram showing the telephoto mode of an optical imaging system according to the seventh embodiment of this disclosure.

[0051] Figure 14A It is shown Figure 13A The diagram shows the aberration characteristics of the optical imaging system.

[0052] Figure 14B It is shown Figure 13B The diagram shows the aberration characteristics of the optical imaging system.

[0053] Throughout the accompanying drawings and detailed embodiments, the same reference numerals refer to the same elements. For purposes of clarity, illustration, and convenience, the drawings may not be drawn to scale, and the relative dimensions, scale, and depiction of elements in the drawings may be exaggerated. Detailed Implementation

[0054] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will become apparent upon understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein, except for operations that must occur in a specific order, as will become apparent upon understanding the disclosure of this application. Furthermore, for clarity and conciseness, descriptions of features well-known in the art may be omitted.

[0055] The features described herein may be implemented in various forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein are provided merely to illustrate some of the many possible ways in which the methods, apparatuses, and / or systems described herein will become apparent upon understanding the disclosure of this application.

[0056] Throughout this specification, when an element such as a layer, region, or substrate is described as being "on," "connected to," or "attached to" another element, the element may be directly "on," directly "connected to," or directly "attached to" the other element, or there may be one or more other elements between the element and the other element. Conversely, when an element is described as being "directly on," "directly connected to," or "directly attached to" another element, there are no other elements between the element and the other element.

[0057] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more items.

[0058] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited by these terms. Rather, these terms are used only to distinguish one component, part, region, layer, or section from another. Therefore, without departing from the teachings of the examples described herein, the first component, first part, first region, first layer, or first section mentioned in these examples may also be referred to as a second component, second part, second region, second layer, or second section.

[0059] Spatial relative terms such as “above,” “above,” “below,” and “under” may be used herein for descriptive convenience to describe the relationship of one element relative to another, as shown in the accompanying drawings. In addition to covering the orientation depicted in the drawings, these spatial relative terms are intended to also cover different orientations of the device in use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “above” another element would be located “below” or “under” that other element. Thus, depending on the spatial orientation of the device, the term “above” covers both orientations of “above” and “below”. The device may also be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0060] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the terms “a,” “an,” and “the” are intended to include the plural form as well. The terms “comprising,” “including,” and “having” indicate the presence of the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0061] In the lens configuration diagrams in the accompanying drawings, for clarity of illustration, the thickness, size, and shape of the lenses may be slightly exaggerated, and in particular, the spherical or aspherical shapes of the lenses shown in the lens configuration diagrams are merely examples, and the spherical or aspherical shapes of the lenses are not limited thereto.

[0062] The optical imaging system according to the embodiments of this disclosure can be installed in a portable electronic device. For example, the optical imaging system may be a component of a camera module installed in a portable electronic device. The portable electronic device may be, for example, a mobile communication terminal, a smartphone, a tablet PC, or other portable electronic devices.

[0063] In embodiments of this disclosure, the first lens (or foremost lens) refers to the lens closest to the object side of the optical imaging system, and the last lens (or final lens) refers to the lens closest to the imaging surface (or image sensor) of the optical imaging system.

[0064] Furthermore, in each lens, the object side refers to the surface of the lens closest to the object side of the optical imaging system, and the image side refers to the surface of the lens closest to the image side of the optical imaging system.

[0065] Furthermore, in this specification, the units for the values ​​of the radius of curvature of the lens, the thickness of the lens, the distance between the lenses, the focal length of the lens, and various other distances are all expressed in millimeters (mm), and the unit for the field of view (FOV) of the optical imaging system is expressed in degrees.

[0066] Furthermore, in the description of lens shape, stating that the surface of the lens is convex means that the paraxial region of the surface is convex, and stating that the surface of the lens is concave means that the paraxial region of the surface is concave.

[0067] Therefore, even when the surface of the lens is convex, the edge portion of the surface can be concave. Similarly, even when the surface of the lens is concave, the edge portion of the lens can be convex.

[0068] The paraxial region of a lens surface is a very narrow area on the lens surface that is close to the optical axis.

[0069] More specifically, the paraxial region of the lens surface is the central portion of the lens surface that surrounds and includes the optical axis of the lens surface, in which light rays incident on the lens surface form a small angle θ with the optical axis, and the approximations sinθ≈θ, tanθ≈θ, and cosθ≈1 are valid.

[0070] An imaging surface can refer to a virtual surface on which an optical imaging system focuses light. Alternatively, an imaging surface can refer to a surface of an image sensor that receives light passing through the optical imaging system.

[0071] An optical imaging system according to an embodiment of the present disclosure includes a plurality of lens groups. For example, the optical imaging system may include 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.

[0072] Each of the first through fourth lens groups includes multiple lenses. For example, an optical imaging system includes at least eight lenses.

[0073] Multiple lenses can be spaced apart from each other by a predetermined distance along the optical axis. Some of these distances can change when the focal length of the optical imaging system changes between wide-angle and telephoto modes.

[0074] In one 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, and an eighth lens 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.

[0075] The optical imaging system according to embodiments of this disclosure may further include a reflective member having a reflective surface that alters the optical path. For example, the reflective member may be a mirror or a prism.

[0076] By altering the optical path through a reflective element, the optical path can be extended in a relatively narrow space.

[0077] Therefore, it is possible to miniaturize optical imaging systems while allowing them to have long focal lengths.

[0078] In addition, the optical imaging system may also include an image sensor for converting an incident image of an object into an electrical signal.

[0079] In addition, the optical imaging system may also include an infrared cutoff filter (hereinafter referred to as a filter) for blocking infrared light. The filter may be positioned between the final lens and the image sensor.

[0080] Furthermore, the optical imaging system may also include an aperture stop disposed between the second lens group and the third lens group. In one embodiment, the aperture stop may be disposed between the fifth lens and the sixth lens, and may be aligned with the object side surface of the sixth lens.

[0081] In an embodiment, the first lens group may include a first lens and a second lens, the second lens group may include a third lens, a fourth lens and a fifth lens, the third lens group may include a sixth lens and a seventh lens, and the fourth lens group may include an eighth lens.

[0082] The reflecting element can be disposed between the first lens group and the second lens group. That is, the reflecting element can be disposed between the second lens and the third lens.

[0083] The total focal length of the optical imaging system can be changed by moving at least one of the first lens group to the fourth lens group.

[0084] For example, the gap between the first lens group and the second lens group can be varied. For example, the first lens group can be fixed, and the second lens group can be configured to move along the optical axis.

[0085] The total focal length of the optical imaging system can be changed as the second lens group moves from the object side of the optical imaging system toward the imaging plane of the optical imaging system. For example, the optical imaging system can be changed from wide-angle mode to telephoto mode.

[0086] Since the first lens group is located at the foremost position in the optical imaging system, it is easy to achieve waterproofing and dustproofing when the first lens group is fixed.

[0087] The first lens group is disposed in front of the reflecting member. Furthermore, the first lens group includes at least one lens having a meniscus shape convex toward the object side, and the first lens group as a whole has positive refractive power.

[0088] In one embodiment, the first lens group may include a first lens and a second lens. The combined focal length of the first lens and the second lens has a positive value.

[0089] Furthermore, the first and second lenses can be made of materials with different optical properties. For example, one of the first and second lenses can be made of a material with a low Abbe number, and the other can be made of a material with a high Abbe number. Therefore, the chromatic aberration correction capability of the optical imaging system can be improved.

[0090] In an embodiment, the Abbe number of one of the first lens and the second lens may be 50 or greater, and the Abbe number of the other of the first lens and the second lens may be 25 or less.

[0091] In an embodiment, the Abbe number of the lens with positive refractive power in the first lens and the second lens may be 50 or greater, and the Abbe number of the lens with negative refractive power in the first lens and the second lens may be 25 or less.

[0092] The first lens may have a meniscus shape that bulges toward the object side.

[0093] The second lens group comprises multiple lenses and has negative refractive power as a whole.

[0094] In this embodiment, the second lens group includes a third lens, a fourth lens, and a fifth lens. Any one of the third to fifth lenses may have a biconcave shape.

[0095] For example, the third lens may have a biconcave shape, and the fourth lens may have a meniscus shape that convexes toward the object side.

[0096] The third lens group comprises multiple lenses and has positive refractive power as a whole. Furthermore, an aperture stop can be positioned in front of the third lens group.

[0097] Among the multiple lenses included in the third lens group, the lens closest to the aperture stop (e.g., the lens located directly behind the aperture stop) has positive refractive power.

[0098] The combined focal length of the first and second lens groups can be negative. That is, because the light passing through the first and second lens groups diverges, the lens closest to the aperture among the lenses included in the third lens group can have positive refractive power, thereby reducing the diameter of the lens placed behind it.

[0099] In this embodiment, the third lens group includes a sixth lens and a seventh lens.

[0100] The sixth lens can have a biconvex shape and can have positive refractive power. The seventh lens can have a meniscus shape that convexes towards the object side and can have negative refractive power.

[0101] The third lens group can be a fixed lens group that does not move.

[0102] The fourth lens group includes at least one lens and has positive refractive power overall.

[0103] In one embodiment, the fourth lens group includes an eighth lens, and the eighth lens may have positive refractive power.

[0104] Depending on the change in the total focal length of the optical imaging system, at least one of the first to fourth lens groups can be moved to correct the focal position.

[0105] For example, the fourth lens group can be configured to move along the optical axis. When the fourth lens group moves, the gap between the third and fourth lens groups, as well as the gap between the fourth lens group and the image sensor, can change.

[0106] When the total focal length of the optical imaging system changes from wide-angle mode to telephoto mode, the fourth lens group can move along the optical axis to correct the focal position.

[0107] In other words, the second lens group can move along the optical axis to change the total focal length of the optical imaging system (optical zoom function), and as the total focal length of the optical imaging system changes, the fourth lens group can move along the optical axis to correct the focal position.

[0108] Therefore, the optical imaging system according to the embodiments of this disclosure has an optical zoom function.

[0109] At least one lens included in each lens group has an aspherical surface defined by Equation 1 below.

[0110] Equation 1:

[0111]

[0112] In Equation 1, c is the curvature of the lens surface and is equal to the reciprocal of the radius of curvature of the lens surface at the optical axis of the lens surface. K is the conic constant, and Y is the distance from an arbitrary point on the aspherical surface of the lens to the optical axis. In addition, the constants A to H, J, and L to P are aspherical surface coefficients. Z (also referred to as sag) is the distance in the direction parallel to the optical axis 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 perpendicular to the optical axis and intersecting the vertex of the aspherical surface.

[0113] The optical imaging system according to an embodiment in the present disclosure may satisfy any one or any combination of any two or more of the following conditional expressions 1 to 12.

[0114] 0.1 < air_T12 < 2.5 (Conditional Expression 1)

[0115] 0.1 < air_T45 < 1.0 (Conditional Expression 2)

[0116] 0.1 < n1 - n2 < 0.2 (Conditional Expression 3)

[0117] 0.08 < n5 - n4 < 0.2 (Conditional Expression 4)

[0118] 0.1 < fw / f2 < 2.0 (Conditional Expression 5)

[0119] 0.1 < fw / f5 < 2.0 (Conditional Expression 6)

[0120] -0.9 < L8sag_1 - L8sag_1 / 2 < -0.01 (Conditional Expression 7)

[0121] 0.4 < DS / TTL < 0.65 (Conditional Expression 8)

[0122] 0.45 < DS / fG1 < 1.0 (Conditional Expression 9)

[0123] 0.6 < fc / fG2 < 1.0 (Conditional Expression 10)

[0124] -3.5 < fG1 / fG2 < -2 (Conditional Expression 11)

[0125] -0.6 < fG2 / fG3 < -0.2 (Conditional Expression 12)

[0126] In an embodiment, the optical imaging system may satisfy 0.1 < air_T12 < 2.5 (Conditional Expression 1), where air_T12 is the distance along the optical axis from the image side surface of the first lens to the object side surface of the second lens.

[0127] By arranging the first lens and the second lens to be separated from each other along the optical axis by a distance satisfying Conditional Expression 1, the degree of freedom of the curvature radius of each lens surface can be increased, which is beneficial to ensuring the performance of the optical imaging system.

[0128] In an embodiment, the optical imaging system can satisfy 0.1 < air_T45 < 1.0 (Conditional Expression 2), where air_T45 is the distance along the optical axis from the image side surface of the fourth lens to the object side surface of the fifth lens.

[0129] By arranging the fourth lens and the fifth lens to be separated from each other along the optical axis by a distance satisfying Conditional Expression 2, the degree of freedom of the curvature radius of each lens surface can be increased, which is beneficial to ensuring the performance of the optical imaging system.

[0130] In an embodiment, the optical imaging system can satisfy 0.1 < n1 - n2 < 0.2 (Conditional Expression 3), where n1 is the refractive index of the first lens and n2 is the refractive index of the second lens.

[0131] By satisfying Conditional Expression 3, the chromatic aberration correction performance can be improved.

[0132] In an embodiment, the optical imaging system can satisfy 0.08 < n5 - n4 < 0.2 (Conditional Expression 4), where n4 is the refractive index of the fourth lens and n5 is the refractive index of the fifth lens.

[0133] By satisfying Conditional Expression 4, the chromatic aberration correction performance can be improved.

[0134] In an embodiment, the optical imaging system can satisfy 0.1 < fw / f2 < 2.0 (Conditional Expression 5), where fw is the total focal length of the optical imaging system in the wide-angle mode and f2 is the focal length of the second lens.

[0135] The resolution can be improved by appropriately adjusting the focal length of the second lens to satisfy Conditional Expression 5.

[0136] In an embodiment, the optical imaging system can satisfy 0.1 < fw / f5 < 2.0 (Conditional Expression 6), where f5 is the focal length of the fifth lens.

[0137] The resolution can be improved by appropriately adjusting the focal length of the fifth lens to satisfy Conditional Expression 6.

[0138] In an embodiment, the optical imaging system may satisfy -0.9 < L8sag_1 - L8sag_1 / 2 < -0.01 (conditional expression 7), where L8sag_1 is the sag value of the object side surface of the eighth lens at the effective diameter of the object side surface of the eighth lens, and L8sag_1 / 2 is the sag value of the object side surface of the eighth lens at half of the effective diameter of the object side surface of the eighth lens. L8sag_1 and L8sag_1 / 2 can be calculated using Equation 1 above.

[0139] Therefore, the object side surface of the eighth lens may have an inflection point, thereby improving the resolution.

[0140] In an embodiment, the optical imaging system may satisfy 0.4 < DS / TTL < 0.65 (conditional expression 8), where DS is the distance from the object side surface of the first lens group to the aperture along the optical axis, and TTL is the distance from the object side surface of the first lens group to the imaging surface along the optical axis.

[0141] The diameter of the aperture may decrease as the distance between the aperture and the first lens group increases, which helps to reduce the thickness of the optical imaging system (or the thickness of the portable electronic device in which the optical imaging system is provided). However, if the aperture is too far from the first lens group, there is a problem that the total track length (TTL) of the optical imaging system increases.

[0142] In addition, if the aperture is positioned too close to the first lens group, there is a problem that the aperture diameter becomes too large. The increase in the aperture diameter can increase the thickness of the optical imaging system, but since the thickness of the optical imaging system depends on the thickness of the portable electronic device, there are limitations in increasing the aperture diameter.

[0143] Therefore, by satisfying conditional expression 8, the optical imaging system can have an appropriate thickness and TTL.

[0144] In an embodiment, the optical imaging system may satisfy 0.45 < DS / fG1 < 1.0 (conditional expression 9), where fG1 is the focal length of the first lens group.

[0145] Conditional expression 9 represents the relationship between the focal length of the first lens group and the position of the aperture. Since the optical imaging system satisfies the condition 0.45 < DS / fG1 < 1.0, the first lens group has an appropriate refractive power level, and at the same time, the optical imaging system can have an appropriate Fno level, where Fno is the f-number of the optical imaging system.

[0146] In an embodiment, the optical imaging system may satisfy 0.6 < fc / fG2 < 1.0 (conditional expression 10), where fc is the focal length of the biconcave lens included in the second lens group, and fG2 is the focal length of the second lens group.

[0147] The second lens group serves as a changer responsible for the change in the FOV (or the change in the total focal length) of the optical imaging system. Therefore, it is necessary to minimize the change in aberration caused by the movement of the second lens group. The second lens group includes a biconcave lens, and the biconcave lens can have a significant impact on the optical characteristics of the second lens group. Therefore, the optical imaging system can minimize the change in aberration caused by the movement of the second lens group by satisfying conditional expression 10, such that the second lens group has an appropriate level of refractive power while serving as a changer.

[0148] In an embodiment, the optical imaging system can satisfy -3.5 < fG1 / fG2 < -2 (conditional expression 11).

[0149] By satisfying conditional expression 11, the focal lengths of the first lens group and the second lens group can be appropriately adjusted to minimize the occurrence of aberration.

[0150] In an embodiment, the optical imaging system can satisfy -0.6 < fG2 / fG3 < -0.2 (conditional expression 12), where fG3 is the focal length of the third lens group.

[0151] By satisfying conditional expression 12, the focal lengths of the second lens group and the third lens group can be appropriately adjusted to minimize the occurrence of aberration.

[0152] Figure 1A is a diagram showing the wide-angle mode of the optical imaging system according to the first embodiment in the present disclosure, and Figure 1B is a diagram showing the telephoto mode of the optical imaging system according to the first embodiment in the present disclosure.

[0153] In addition, Figure 2A is a diagram showing Figure 1A the aberration characteristics of the wide-angle mode of the optical imaging system shown in Figure 2B is a diagram showing Figure 1B the aberration characteristics of the telephoto mode of the optical imaging system shown in

[0154] The optical imaging system 100 according to the first embodiment in the present disclosure includes a first lens group LG1, a second lens group LG2, a third lens group LG3, and a fourth lens group LG4.

[0155] Starting from the object side of the optical imaging system 100 in sequence, the first lens group LG1 includes a first lens 101 and a second lens 102, the second lens group LG2 includes a third lens 103, a fourth lens 104, and a fifth lens 105, the third lens group LG3 includes a sixth lens 106 and a seventh lens 107, and the fourth lens group LG4 includes an eighth lens 108.

[0156] In addition, the optical imaging system 100 also includes a reflective member R disposed between the first lens group LG1 and the second lens group LG2, and an aperture stop disposed between the second lens group LG2 and the third lens group LG3. The aperture stop is aligned with the object side surface of the third lens group LG3.

[0157] In addition, the optical imaging system 100 may also include a filter 109 and an image sensor. The image sensor may include an imaging surface 110. The imaging surface 110 may refer to the surface on which the optical imaging system 100 forms a focal point.

[0158] The characteristics of each lens (radius of curvature of each lens surface, thickness of each lens or distance between lenses, refractive index of each lens, and Abbe number of each lens) are shown in Table 1 below.

[0159] Table 1

[0160]

[0161]

[0162] Table 2

[0163] distance Wide-angle mode Telephoto mode D1 1.332 6.050 D2 5.454 0.735 D3 2.042 4.329 D4 7.428 5.141

[0164] In Table 2 above, D1 is the distance along the optical axis between the reflecting member R and the third lens 103, D2 is the distance along the optical axis between the fifth lens 105 and the sixth lens 106 (or aperture), D3 is the distance along the optical axis between the seventh lens 107 and the eighth lens 108, and D4 is the distance along the optical axis between the eighth lens 108 and the filter 109.

[0165] The focal length fG1 of the first lens group LG1 is 21.047mm, the focal length fG2 of the second lens group LG2 is -6.803mm, the focal length fG3 of the third lens group LG3 is 14.474mm, and the focal length fG4 of the fourth lens group LG4 is 9.936mm.

[0166] In the first embodiment of this disclosure, the first lens group LG1 generally has positive refractive power, the second lens group LG2 generally has negative refractive power, the third lens group LG3 generally has positive refractive power, and the fourth lens group LG4 generally has positive refractive power.

[0167] The first lens 101 has negative refractive power, the object side of the first lens 101 is convex, and the image side of the first lens 101 is concave.

[0168] The second lens 102 has positive refractive power, and the object side and image side of the second lens 102 are convex.

[0169] The reflecting member R is positioned behind the second lens 102.

[0170] The third lens 103 has negative refractive power, and the object side and image side of the third lens 103 are concave.

[0171] The fourth lens 104 has negative refractive power, the object side of the fourth lens 104 is convex, and the image side of the fourth lens 104 is concave.

[0172] The fifth lens 105 has positive refractive power, the object side of the fifth lens 105 is convex, and the image side of the fifth lens 105 is concave.

[0173] The sixth lens 106 has positive refractive power, and both its object-side and image-side surfaces are convex. An aperture stop is positioned in front of the sixth lens 106 and aligned with its object-side surface. That is, the distance along the optical axis between the aperture stop and the object-side surface of the sixth lens 106 is zero.

[0174] The seventh lens 107 has negative refractive power, the object side of the seventh lens 107 is convex, and the image side of the seventh lens 107 is concave.

[0175] The eighth lens 108 has positive refractive power, the object side of the eighth lens 108 is convex, and the image side of the eighth lens 108 is concave.

[0176] Each surface of the first lens 101 to the eighth lens 108 has the aspheric coefficient shown in Table 3 below. That is, each surface of the first lens 101 to the eighth lens 108 is aspherical.

[0177] Table 3

[0178]

[0179]

[0180] Figure 3A This is a diagram illustrating a wide-angle mode of an optical imaging system according to a second embodiment of this disclosure, and Figure 3B This is a diagram showing the telephoto mode of an optical imaging system according to a second embodiment of the present disclosure.

[0181] also, Figure 4A It is shown Figure 3A A graph showing the aberration characteristics of the wide-angle mode of the optical imaging system illustrated, and Figure 4B It is shown Figure 3B The diagram shows the aberration characteristics of the telephoto mode of the optical imaging system shown.

[0182] The optical imaging system 200 according to the second embodiment of this disclosure includes a first lens group LG1, a second lens group LG2, a third lens group LG3, and a fourth lens group LG4.

[0183] Starting sequentially from the object side of the optical imaging system 200, the first lens group LG1 includes a first lens 201 and a second lens 202, the second lens group LG2 includes a third lens 203, a fourth lens 204 and a fifth lens 205, the third lens group LG3 includes a sixth lens 206 and a seventh lens 207, and the fourth lens group LG4 includes an eighth lens 208.

[0184] In addition, the optical imaging system 200 also includes a reflective member R disposed between the first lens group LG1 and the second lens group LG2, and an aperture stop disposed between the second lens group LG2 and the third lens group LG3. The aperture stop is aligned with the object side surface of the third lens group LG3.

[0185] In addition, the optical imaging system 200 may also include a filter 209 and an image sensor. The image sensor may include an imaging surface 210. The imaging surface 210 may refer to the surface on which the optical imaging system 200 forms a focal point.

[0186] The characteristics of each lens (radius of curvature of each lens surface, thickness of each lens or distance between lenses, refractive index of each lens and Abbe number of each lens) are shown in Table 4 below.

[0187] Table 4

[0188]

[0189] Table 5

[0190] distance Wide-angle mode Telephoto mode D1 1.503 6.500 D2 5.501 0.505 D3 1.939 3.899 D4 7.714 5.755

[0191] In Table 5 above, D1 is the distance along the optical axis between the reflecting member R and the third lens 203, D2 is the distance along the optical axis between the fifth lens 205 and the sixth lens 206 (or aperture), D3 is the distance along the optical axis between the seventh lens 207 and the eighth lens 208, and D4 is the distance along the optical axis between the eighth lens 208 and the filter 209.

[0192] The focal length fG1 of the first lens group LG1 is 21.685mm, the focal length fG2 of the second lens group LG2 is -6.895mm, the focal length fG3 of the third lens group LG3 is 14.979mm, and the focal length fG4 of the fourth lens group LG4 is 9.944mm.

[0193] In the second embodiment of this disclosure, the first lens group LG1 generally has positive refractive power, the second lens group LG2 generally has negative refractive power, the third lens group LG3 generally has positive refractive power, and the fourth lens group LG4 generally has positive refractive power.

[0194] The first lens 201 has negative refractive power, the object side of the first lens 201 is convex, and the image side of the first lens 201 is concave.

[0195] The second lens 202 has positive refractive power, and the object side and image side of the second lens 202 are convex.

[0196] The reflective element R is positioned behind the second lens 202.

[0197] The third lens 203 has negative refractive power, and the object side and image side of the third lens 203 are concave.

[0198] The fourth lens 204 has negative refractive power, the object side of the fourth lens 204 is convex, and the image side of the fourth lens 204 is concave.

[0199] The fifth lens 205 has positive refractive power, the object side of the fifth lens 205 is convex, and the image side of the fifth lens 205 is concave.

[0200] The sixth lens 206 has positive refractive power, and both its object-side and image-side surfaces are convex. An aperture stop is positioned in front of the sixth lens 206 and aligned with its object-side surface. That is, the distance along the optical axis between the aperture stop and the object-side surface of the sixth lens 206 is zero.

[0201] The seventh lens 207 has negative refractive power. The object side of the seventh lens 207 is convex, and the image side of the seventh lens 207 is concave.

[0202] The eighth lens 208 has positive refractive power, the object side of the eighth lens 208 is convex, and the image side of the eighth lens 208 is concave.

[0203] Each surface of the first lens 201 to the eighth lens 208 has the aspheric coefficient shown in Table 6 below. That is, each surface of the first lens 201 to the eighth lens 208 is aspherical.

[0204] Table 6

[0205]

[0206]

[0207] Figure 5AThis is a diagram illustrating a wide-angle mode of an optical imaging system according to a third embodiment of this disclosure, and Figure 5B This is a diagram showing the telephoto mode of an optical imaging system according to a third embodiment of this disclosure.

[0208] also, Figure 6A It is shown Figure 5A A graph showing the aberration characteristics of the wide-angle mode of the optical imaging system illustrated, and Figure 6B It is shown Figure 5B The diagram shows the aberration characteristics of the telephoto mode of the optical imaging system shown.

[0209] The optical imaging system 300 according to the third embodiment of this disclosure includes a first lens group LG1, a second lens group LG2, a third lens group LG3, and a fourth lens group LG4.

[0210] Starting sequentially from the object side of the optical imaging system 300, the first lens group LG1 includes a first lens 301 and a second lens 302, the second lens group LG2 includes a third lens 303, a fourth lens 304 and a fifth lens 305, the third lens group LG3 includes a sixth lens 306 and a seventh lens 307, and the fourth lens group LG4 includes an eighth lens 308.

[0211] In addition, the optical imaging system 300 also includes a reflective member R disposed between the first lens group LG1 and the second lens group LG2, and an aperture stop disposed between the second lens group LG2 and the third lens group LG3. The aperture stop is aligned with the object side surface of the third lens group LG3.

[0212] In addition, the optical imaging system 300 may also include a filter 309 and an image sensor. The image sensor may include an imaging surface 310. The imaging surface 310 may refer to the surface on which the optical imaging system 300 forms a focal point.

[0213] The characteristics of each lens (radius of curvature of each lens surface, thickness of each lens or distance between lenses, refractive index of each lens and Abbe number of each lens) are shown in Table 7 below.

[0214] Table 7

[0215]

[0216] Table 8

[0217] distance Wide-angle mode Telephoto mode D1 1.620 6.500 D2 5.380 0.500 D3 2.062 4.133 D4 7.428 5.357

[0218] In Table 8 above, D1 is the distance along the optical axis between the reflecting member R and the third lens 303, D2 is the distance along the optical axis between the fifth lens 305 and the sixth lens 306 (or aperture), D3 is the distance along the optical axis between the seventh lens 307 and the eighth lens 308, and D4 is the distance along the optical axis between the eighth lens 308 and the filter 309.

[0219] The focal length fG1 of the first lens group LG1 is 21.520mm, the focal length fG2 of the second lens group LG2 is -6.829mm, the focal length fG3 of the third lens group LG3 is 14.774mm, and the focal length fG4 of the fourth lens group LG4 is 9.720mm.

[0220] In the third embodiment of this disclosure, the first lens group LG1 generally has positive refractive power, the second lens group LG2 generally has negative refractive power, the third lens group LG3 generally has positive refractive power, and the fourth lens group LG4 generally has positive refractive power.

[0221] The first lens 301 has negative refractive power, the object side of the first lens 301 is convex, and the image side of the first lens 301 is concave.

[0222] The second lens 302 has positive refractive power, and the object side and image side of the second lens 302 are convex.

[0223] The reflecting member R is positioned behind the second lens 302.

[0224] The third lens 303 has negative refractive power, and the object side and image side of the third lens 303 are concave.

[0225] The fourth lens 304 has negative refractive power, the object side of the fourth lens 304 is convex, and the image side of the fourth lens 304 is concave.

[0226] The fifth lens 305 has positive refractive power, the object side of the fifth lens 305 is convex, and the image side of the fifth lens 305 is concave.

[0227] The sixth lens 306 has positive refractive power, and both its object-side and image-side surfaces are convex. An aperture stop is positioned in front of the sixth lens 306 and aligned with its object-side surface. That is, the distance along the optical axis between the aperture stop and the object-side surface of the sixth lens 306 is zero.

[0228] The seventh lens 307 has negative refractive power, the object side of the seventh lens 307 is convex, and the image side of the seventh lens 307 is concave.

[0229] The eighth lens 308 has positive refractive power, and the object side and image side of the eighth lens 308 are convex.

[0230] Each surface of the first lens 301 to the eighth lens 308 has the aspheric coefficient shown in Table 9 below. That is, each surface of the first lens 301 to the eighth lens 308 is aspherical.

[0231] Table 9

[0232]

[0233]

[0234] Figure 7A This is a diagram showing the wide-angle mode of an optical imaging system according to the fourth embodiment of this disclosure, and Figure 7B This is a diagram showing the telephoto mode of an optical imaging system according to the fourth embodiment of this disclosure.

[0235] also, Figure 8A It is shown Figure 7A A graph showing the aberration characteristics of the wide-angle mode of the optical imaging system illustrated, and Figure 8B It is shown Figure 7B The diagram shows the aberration characteristics of the telephoto mode of the optical imaging system shown.

[0236] The optical imaging system 400 according to the fourth embodiment of this disclosure includes a first lens group LG1, a second lens group LG2, a third lens group LG3, and a fourth lens group LG4.

[0237] Starting sequentially from the object side of the optical imaging system 400, the first lens group LG1 includes a first lens 401 and a second lens 402, the second lens group LG2 includes a third lens 403, a fourth lens 404 and a fifth lens 405, the third lens group LG3 includes a sixth lens 406 and a seventh lens 407, and the fourth lens group LG4 includes an eighth lens 408.

[0238] In addition, the optical imaging system 400 also includes a reflective member R disposed between the first lens group LG1 and the second lens group LG2, and an aperture stop disposed between the second lens group LG2 and the third lens group LG3. The aperture stop is aligned with the object side surface of the third lens group LG3.

[0239] In addition, the optical imaging system 400 may also include a filter 409 and an image sensor. The image sensor may include an imaging surface 410. The imaging surface 410 may refer to the surface on which the optical imaging system 400 forms a focal point.

[0240] The characteristics of each lens (radius of curvature of each lens surface, thickness of each lens or distance between lenses, refractive index of each lens and Abbe number of each lens) are shown in Table 10 below.

[0241] Table 10

[0242]

[0243]

[0244] Table 11

[0245] distance Wide-angle mode Telephoto mode D1 1.600 13.799 D2 15.279 3.080 D3 3.681 4.563 D4 12.932 12.050

[0246] In Table 11 above, D1 is the distance along the optical axis between the reflecting member R and the third lens 403, D2 is the distance along the optical axis between the fifth lens 405 and the sixth lens 406 (or aperture), D3 is the distance along the optical axis between the seventh lens 407 and the eighth lens 408, and D4 is the distance along the optical axis between the eighth lens 408 and the filter 409.

[0247] The focal length fG1 of the first lens group LG1 is 53.884mm, the focal length fG2 of the second lens group LG2 is -18.446mm, the focal length fG3 of the third lens group LG3 is 34.094mm, and the focal length fG4 of the fourth lens group LG4 is 19.855mm.

[0248] In the fourth embodiment of this disclosure, the first lens group LG1 generally has positive refractive power, the second lens group LG2 generally has negative refractive power, the third lens group LG3 generally has positive refractive power, and the fourth lens group LG4 generally has positive refractive power.

[0249] The first lens 401 has negative refractive power, the object side of the first lens 401 is convex, and the image side of the first lens 401 is concave.

[0250] The second lens 402 has positive refractive power, and the object side and image side of the second lens 402 are convex.

[0251] The reflecting member R is positioned behind the second lens 402.

[0252] The third lens 403 has negative refractive power, and the object side and image side of the third lens 403 are concave.

[0253] The fourth lens 404 has negative refractive power, the object side of the fourth lens 404 is convex, and the image side of the fourth lens 404 is concave.

[0254] The fifth lens 405 has positive refractive power, the object side of the fifth lens 405 is convex, and the image side of the fifth lens 405 is concave.

[0255] The sixth lens 406 has positive refractive power, and both its object-side and image-side surfaces are convex. An aperture stop is positioned in front of the sixth lens 406 and aligned with its object-side surface. That is, the distance along the optical axis between the aperture stop and the object-side surface of the sixth lens 406 is zero.

[0256] The seventh lens 407 has negative refractive power. The object side of the seventh lens 407 is convex, and the image side of the seventh lens 407 is concave.

[0257] The eighth lens 408 has positive refractive power, the object side of the eighth lens 408 is convex, and the image side of the eighth lens 408 is concave.

[0258] Each surface of the first lens 401 to the eighth lens 408 has the aspheric coefficient shown in Table 12 below. That is, each surface of the first lens 401 to the eighth lens 408 is aspherical.

[0259] Table 12

[0260]

[0261]

[0262] Figure 9A This is a diagram showing the wide-angle mode of an optical imaging system according to the fifth embodiment of this disclosure, and Figure 9B This is a diagram showing the telephoto mode of an optical imaging system according to the fifth embodiment of this disclosure.

[0263] also, Figure 10A It is shown Figure 9A A graph showing the aberration characteristics of the wide-angle mode of the optical imaging system illustrated, and Figure 10B It is shown Figure 9B The diagram shows the aberration characteristics of the telephoto mode of the optical imaging system shown.

[0264] The optical imaging system 500 according to the fifth embodiment of this disclosure includes a first lens group LG1, a second lens group LG2, a third lens group LG3, and a fourth lens group LG4.

[0265] Starting from the object side of the optical imaging system 500, the first lens group LG1 includes a first lens 501 and a second lens 502, the second lens group LG2 includes a third lens 503, a fourth lens 504 and a fifth lens 505, the third lens group LG3 includes a sixth lens 506 and a seventh lens 507, and the fourth lens group LG4 includes an eighth lens 508.

[0266] In addition, the optical imaging system 500 also includes a reflective member R disposed between the first lens group LG1 and the second lens group LG2, and an aperture stop disposed between the second lens group LG2 and the third lens group LG3. The aperture stop is aligned with the object side surface of the third lens group LG3.

[0267] In addition, the optical imaging system 500 may also include a filter 509 and an image sensor. The image sensor may include an imaging surface 510. The imaging surface 510 may refer to the surface on which the optical imaging system 500 forms a focal point.

[0268] The characteristics of each lens (radius of curvature of each lens surface, thickness of each lens or distance between lenses, refractive index of each lens and Abbe number of each lens) are shown in Table 13 below.

[0269] Table 13

[0270]

[0271] Table 14

[0272] distance Wide-angle mode Telephoto mode D1 1.600 14.199 D2 14.873 2.274 D3 3.634 4.687 D4 13.013 11.959

[0273] In Table 14 above, D1 is the distance along the optical axis between the reflecting member R and the third lens 503, D2 is the distance along the optical axis between the fifth lens 505 and the sixth lens 506 (or aperture), D3 is the distance along the optical axis between the seventh lens 507 and the eighth lens 508, and D4 is the distance along the optical axis between the eighth lens 508 and the filter 509.

[0274] The focal length fG1 of the first lens group LG1 is 53.748mm, the focal length fG2 of the second lens group LG2 is -19.029mm, the focal length fG3 of the third lens group LG3 is 34.694mm, and the focal length fG4 of the fourth lens group LG4 is 19.944mm.

[0275] In the fifth embodiment of this disclosure, the first lens group LG1 generally has positive refractive power, the second lens group LG2 generally has negative refractive power, the third lens group LG3 generally has positive refractive power, and the fourth lens group LG4 generally has positive refractive power.

[0276] The first lens 501 has negative refractive power, the object side of the first lens 501 is convex, and the image side of the first lens 501 is concave.

[0277] The second lens 502 has positive refractive power, and the object side and image side of the second lens 502 are convex.

[0278] The reflective element R is positioned behind the second lens 502.

[0279] The third lens 503 has negative refractive power, and the object side and image side of the third lens 503 are concave.

[0280] The fourth lens 504 has negative refractive power, the object side of the fourth lens 504 is convex, and the image side of the fourth lens 504 is concave.

[0281] The fifth lens 505 has positive refractive power, and the object side and image side of the fifth lens 505 are convex.

[0282] The sixth lens 506 has positive refractive power, and both its object-side and image-side surfaces are convex. An aperture stop is positioned in front of the sixth lens 506 and aligned with its object-side surface. That is, the distance along the optical axis between the aperture stop and the object-side surface of the sixth lens 506 is zero.

[0283] The seventh lens 507 has negative refractive power. The object side of the seventh lens 507 is convex, and the image side of the seventh lens 507 is concave.

[0284] The eighth lens 508 has positive refractive power, the object side of the eighth lens 508 is convex, and the image side of the eighth lens 508 is concave.

[0285] Each surface of the first lens 501 to the eighth lens 508 has the aspheric coefficient shown in Table 15 below. That is, each surface of the first lens 501 to the eighth lens 508 is aspherical.

[0286] Table 15

[0287]

[0288]

[0289] Figure 11A This is a diagram showing the wide-angle mode of an optical imaging system according to the sixth embodiment of this disclosure, and Figure 11B This is a diagram showing the telephoto mode of an optical imaging system according to a sixth embodiment of this disclosure.

[0290] also, Figure 12A It is shown Figure 11AA graph showing the aberration characteristics of the wide-angle mode of the optical imaging system illustrated, and Figure 12B It is shown Figure 11B The diagram shows the aberration characteristics of the telephoto mode of the optical imaging system shown.

[0291] An optical imaging system 600 according to a sixth embodiment of the present disclosure includes a first lens group LG1, a second lens group LG2, a third lens group LG3, and a fourth lens group LG4.

[0292] Starting sequentially from the object side of the optical imaging system 600, the first lens group LG1 includes a first lens 601 and a second lens 602, the second lens group LG2 includes a third lens 603, a fourth lens 604 and a fifth lens 605, the third lens group LG3 includes a sixth lens 606 and a seventh lens 607, and the fourth lens group LG4 includes an eighth lens 608.

[0293] In addition, the optical imaging system 600 also includes a reflective member R disposed between the first lens group LG1 and the second lens group LG2, and an aperture stop disposed between the second lens group LG2 and the third lens group LG3. The aperture stop is aligned with the object side surface of the third lens group LG3.

[0294] In addition, the optical imaging system 600 may also include a filter 609 and an image sensor. The image sensor may include an imaging surface 610. The imaging surface 610 may refer to the surface on which the optical imaging system 600 forms a focal point.

[0295] The characteristics of each lens (radius of curvature of each lens surface, thickness of each lens or distance between lenses, refractive index of each lens and Abbe number of each lens) are shown in Table 16 below.

[0296] Table 16

[0297]

[0298] Table 17

[0299] distance Wide-angle mode Telephoto mode D1 1.600 14.496 D2 15.471 2.575 D3 3.731 4.556 D4 13.097 12.272

[0300] In Table 17 above, D1 is the distance along the optical axis between the reflecting member R and the third lens 603, D2 is the distance along the optical axis between the fifth lens 605 and the sixth lens 606 (or aperture), D3 is the distance along the optical axis between the seventh lens 607 and the eighth lens 608, and D4 is the distance along the optical axis between the eighth lens 608 and the filter 609.

[0301] The focal length fG1 of the first lens group LG1 is 55.277mm, the focal length fG2 of the second lens group LG2 is -19.455mm, the focal length fG3 of the third lens group LG3 is 35.871mm, and the focal length fG4 of the fourth lens group LG4 is 19.944mm.

[0302] In the sixth embodiment of this disclosure, the first lens group LG1 generally has positive refractive power, the second lens group LG2 generally has negative refractive power, the third lens group LG3 generally has positive refractive power, and the fourth lens group LG4 generally has positive refractive power.

[0303] The first lens 601 has negative refractive power, the object side of the first lens 601 is convex, and the image side of the first lens 601 is concave.

[0304] The second lens 602 has positive refractive power, and the object side and image side of the second lens 602 are convex.

[0305] The reflective element R is positioned behind the second lens 602.

[0306] The third lens 603 has negative refractive power, and the object side and image side of the third lens 603 are concave.

[0307] The fourth lens 604 has negative refractive power. The object side of the fourth lens 604 is convex, while the image side of the fourth lens 604 is concave.

[0308] The fifth lens 605 has positive refractive power, and the object side and image side of the fifth lens 605 are convex.

[0309] The sixth lens 606 has positive refractive power, and both its object-side and image-side surfaces are convex. An aperture stop is positioned in front of the sixth lens 606 and aligned with its object-side surface. That is, the distance along the optical axis between the aperture stop and the object-side surface of the sixth lens 606 is zero.

[0310] The seventh lens 607 has negative refractive power, the object side of the seventh lens 607 is convex, and the image side of the seventh lens 607 is concave.

[0311] The eighth lens 608 has positive refractive power, the object side of the eighth lens 608 is convex, and the image side of the eighth lens 608 is concave.

[0312] Each surface of the first lens 601 to the eighth lens 608 has the aspheric coefficient shown in Table 18 below. That is, each surface of the first lens 601 to the eighth lens 608 is aspherical.

[0313] Table 18

[0314]

[0315]

[0316] Figure 13A This is a diagram showing the wide-angle mode of an optical imaging system according to the seventh embodiment of this disclosure, and Figure 13B This is a diagram showing the telephoto mode of an optical imaging system according to the seventh embodiment of this disclosure.

[0317] also, Figure 14A It is shown Figure 13A A graph showing the aberration characteristics of the wide-angle mode of the optical imaging system illustrated, and Figure 14B It is shown Figure 13B The diagram shows the aberration characteristics of the telephoto mode of the optical imaging system shown.

[0318] The optical imaging system 700 according to the seventh embodiment of this disclosure includes a first lens group LG1, a second lens group LG2, a third lens group LG3, and a fourth lens group LG4.

[0319] Starting sequentially from the object side of the optical imaging system 700, the first lens group LG1 includes a first lens 701 and a second lens 702, the second lens group LG2 includes a third lens 703, a fourth lens 704 and a fifth lens 705, the third lens group LG3 includes a sixth lens 706 and a seventh lens 707, and the fourth lens group LG4 includes an eighth lens 708.

[0320] In addition, the optical imaging system 700 also includes a reflective member R disposed between the first lens group LG1 and the second lens group LG2, and an aperture stop disposed between the second lens group LG2 and the third lens group LG3. The aperture stop is aligned with the object side surface of the third lens group LG3.

[0321] In addition, the optical imaging system 700 may also include a filter 709 and an image sensor. The image sensor may include an imaging surface 710. The imaging surface 710 may refer to the surface on which the optical imaging system 700 forms a focal point.

[0322] The characteristics of each lens (radius of curvature of each lens surface, thickness of each lens or distance between lenses, refractive index of each lens and Abbe number of each lens) are shown in Table 19 below.

[0323] Table 19

[0324]

[0325]

[0326] Table 20

[0327] distance Wide-angle mode Telephoto mode D1 1.206 12.345 D2 11.889 0.750 D3 2.872 3.723 D4 14.278 13.428

[0328] In Table 20 above, D1 is the distance along the optical axis between the reflecting member R and the third lens 703, D2 is the distance along the optical axis between the fifth lens 705 and the sixth lens 706 (or aperture), D3 is the distance along the optical axis between the seventh lens 707 and the eighth lens 708, and D4 is the distance along the optical axis between the eighth lens 708 and the filter 709.

[0329] The focal length fG1 of the first lens group LG1 is 48.256mm, the focal length fG2 of the second lens group LG2 is -16.347mm, the focal length fG3 of the third lens group LG3 is 45.775mm, and the focal length fG4 of the fourth lens group LG4 is 16.614mm.

[0330] In the seventh embodiment of this disclosure, the first lens group LG1 generally has positive refractive power, the second lens group LG2 generally has negative refractive power, the third lens group LG3 generally has positive refractive power, and the fourth lens group LG4 generally has positive refractive power.

[0331] The first lens 701 has negative refractive power, the object side of the first lens 701 is convex, and the image side of the first lens 701 is concave.

[0332] The second lens 702 has positive refractive power, and the object side and image side of the second lens 702 are convex.

[0333] The reflective element R is positioned behind the second lens 702.

[0334] The third lens 703 has negative refractive power, and the object side and image side of the third lens 703 are concave.

[0335] The fourth lens 704 has positive refractive power, the object side of the fourth lens 704 is convex, and the image side of the fourth lens 704 is concave.

[0336] The fifth lens 705 has positive refractive power, the object side of the fifth lens 705 is convex, and the image side of the fifth lens 705 is concave.

[0337] The sixth lens 706 has positive refractive power, and both its object-side and image-side surfaces are convex. An aperture stop is positioned in front of the sixth lens 706 and aligned with its object-side surface. That is, the distance along the optical axis between the aperture stop and the object-side surface of the sixth lens 706 is zero.

[0338] The seventh lens 707 has negative refractive power, the object side of the seventh lens 707 is convex, and the image side of the seventh lens 707 is concave.

[0339] The eighth lens 708 has positive refractive power, and the object side and image side of the eighth lens 708 are convex.

[0340] Each surface of the first lens 701 to the eighth lens 708 has the aspheric coefficient shown in Table 21 below. That is, each surface of the first lens 701 to the eighth lens 708 is an aspherical surface.

[0341] Table 21

[0342]

[0343]

[0344] Table 22 below shows the values ​​of various optical properties in the first to seventh embodiments of this disclosure.

[0345] Table 22

[0346]

[0347]

[0348] In Table 22 above, ft represents the total focal length of the optical imaging system in telephoto mode, Fnow represents the f-number of the optical imaging system in wide-angle mode, and Fnot represents the f-number of the optical imaging system in telephoto mode.

[0349] Table 23 below shows the values ​​of conditional expressions 1 to 12 in the first to seventh embodiments of this disclosure.

[0350] Table 23

[0351]

[0352]

[0353] An optical imaging system according to an embodiment of the present disclosure can achieve zoom functionality by changing the focal length.

[0354] While this disclosure includes specific examples, it will be apparent upon understanding this disclosure that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The description of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Suitable results may still be achieved if the described techniques are performed in a different order, and / or if components in the described system, architecture, device, or circuit are combined in different ways and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of this disclosure is not limited by the specific embodiments but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included in this disclosure.

Claims

1. An optical imaging system, characterized by, The optical imaging system includes: a first lens group, a second lens group, a third lens group, and a fourth lens group arranged 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 a reflective member disposed between the first lens group and the second lens group, wherein the second lens group and the fourth lens group are each configured to be movable along the optical axis, the first lens group has positive refractive power, and the optical imaging system satisfies the following conditional expression: -3.5 < fG1 / fG2 < -2 wherein fG1 is a focal length of the first lens group, and fG2 is a focal length of the second lens group.

2. The optical imaging system of claim 1, wherein, The first lens group includes a first lens and a second lens arranged in order from an object side of the first lens group toward the image plane along the optical axis, and one of the first lens and the second lens has an Abbe number of 50 or more, and the other of the first lens and the second lens has an Abbe number of 25 or less.

3. The optical imaging system of claim 2, wherein, The first lens and the second lens have refractive powers of opposite signs, and of the first lens and the second lens, the lens having an Abbe number of 50 or more has positive refractive power, and the lens having an Abbe number of 25 or less has negative refractive power.

4. The optical imaging system of claim 2, wherein, The optical imaging system satisfies the following conditional expression: 0.1 < air_T12 < 2.5 wherein air_T12 is a distance along the optical axis from an image side surface of the first lens to an object side surface of the second lens.

5. The optical imaging system of claim 2, wherein, The optical imaging system satisfies the following conditional expression: 0.1 < fw / f2 < 2.0 wherein fw is a total focal length of the optical imaging system in a wide-angle mode, and f2 is a focal length of the second lens.

6. The optical imaging system of claim 1, wherein, The second lens group has negative refractive power and includes a plurality of lenses, and one of the plurality of lenses of the second lens group has a double-concave shape.

7. The optical imaging system of claim 6, wherein, The optical imaging system satisfies the following conditional expression: 0.6 < fc / fG2 < 1.0 wherein fc is a focal length of the lens having the double-concave shape among the plurality of lenses of the second lens group.

8. The optical imaging system of claim 1, wherein, The second lens group includes a third lens, a fourth lens, and a fifth lens arranged in order from an object side of the second lens group toward the image plane along the optical axis, and The optical imaging system satisfies the following conditional expression: 0.1 < air_T45 < 1.0 wherein air_T45 is a distance along the optical axis from an image side surface of the fourth lens to an object side surface of the fifth lens.

9. The optical imaging system of claim 8, wherein, The optical imaging system satisfies the following conditional expression: 0.1 < fw / f5 < 2.0 wherein fw is a total focal length of the optical imaging system in a wide-angle mode, and f5 is a focal length of the fifth lens.

10. The optical imaging system of claim 1, wherein, The first lens group includes a first lens and a second lens arranged in order from an object side of the first lens group toward the image plane along the optical axis, The second lens group includes a third lens, a fourth lens, and a fifth lens arranged in order from an object side of the second lens group toward the image plane along the optical axis, and The optical imaging system satisfies the following conditional expression: 0.1 < n1-n2 < 0.2 0.08 < n5-n4 < 0.2 where n1 is a refractive index of the first lens, n2 is a refractive index of the second lens, n4 is a refractive index of the fourth lens, and n5 is a refractive index of the fifth lens.

11. The optical imaging system of claim 1, wherein, The third lens group and the fourth lens group each have positive refractive power.

12. The optical imaging system of claim 1, wherein, The optical imaging system further includes a stop disposed between the second lens group and the third lens group, The third lens group includes a plurality of lenses, and Among the plurality of lenses of the third lens group, a lens disposed closest to the stop has positive refractive power.

13. The optical imaging system of claim 12, wherein, The optical imaging system satisfies the following conditional expression: 0.4 < DS / TTL < 0.65 where DS is a distance along the optical axis from an object side surface of the first lens group to the stop, and TTL is a distance along the optical axis from the object side surface of the first lens group to the image surface.

14. The optical imaging system of claim 12, wherein, The optical imaging system satisfies the following conditional expression: 0.45 < DS / fG1 < 1.0 where DS is a distance along the optical axis from an object side surface of the first lens group to the stop.

15. The optical imaging system of claim 1, wherein, The optical imaging system satisfies the following conditional expression: -0.6 < fG2 / fG3 < -0.2 where fG3 is a focal length of the third lens group.

16. The optical imaging system of claim 1, wherein, The first lens group includes a first lens and a second lens disposed in order along the optical axis from an object side surface of the first lens group toward the image surface, The second lens group includes a third lens, a fourth lens, and a fifth lens disposed in order along the optical axis from an object side surface of the second lens group toward the image surface, The third lens group includes a sixth lens and a seventh lens disposed in order along the optical axis from an object side surface of the third lens group toward the image surface, The fourth lens group includes an eighth lens, and The optical imaging system satisfies the following conditional expression: -0.9 < L8sag_1-L8sag_1 / 2 < -0.01 where L8sag_1 is a sag value of an object side surface of the eighth lens at an effective diameter of the object side surface of the eighth lens, and L8sag_1 / 2 is a sag value of the object side surface of the eighth lens at half of the effective diameter of the object side surface of the eighth lens.

Images