Optical image capturing system

Abstract

The optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens disposed in order from an object side, and first and second reflective members disposed on the object side of the first lens, each of the first and second reflective members having a free-form surface.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2020-0144092 filed in the Korean Intellectual Property Office on November 2, 2020, the disclosure of which is incorporated herein in its entirety by reference for all purposes. Technical Field

[0003] The present disclosure relates to an optical imaging system including a reflective member formed to have a freely curved surface. Background Art

[0004] A camera module may be mounted on a mobile terminal device such as a smart phone, a laptop computer, etc. A camera module mounted on a mobile terminal device is generally configured to capture images of an object located within a short distance. However, in the case of frequent outdoor photography through a camera module of a mobile terminal device, a camera module capable of capturing images of an object located at a long distance is required. However, due to limitations on the installation space of the camera module of the mobile terminal device, it may be difficult to design a camera module and an optical imaging system capable of capturing long-distance images.

[0005] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with respect to the present disclosure. Summary of the invention

[0006] The purpose of providing this summary is to introduce a selection of inventive concepts in a concise form, and these inventive concepts will be further described in the following detailed description. This summary is not intended to identify the key features or essential features of the subject matter claimed, nor is it intended to help determine the scope of the subject matter claimed.

[0007] In a general aspect, an optical imaging system includes: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, which are arranged in sequence from an object side; and a first reflecting member and a second reflecting member, which are arranged on the object side of the first lens, each of the first reflecting member and the second reflecting member having a free-form surface.

[0008] The first reflective member may have a concave reflective surface.

[0009] The second reflective member may have a convex reflective surface.

[0010] The first lens may have a convex object-side surface.

[0011] The second lens may have a concave object-side surface.

[0012] The third lens may have a convex object side surface.

[0013] The fourth lens may have a convex object side surface.

[0014] The fifth lens may have a concave object side surface.

[0015] The ratio f / fL may be greater than 1.40 and less than 1.80, where f is the focal length of the optical imaging system, and fL is the combined focal length of the first lens to the fifth lens.

[0016] The optical imaging system may further include an optical path folding member disposed on the object side of the first reflecting member.

[0017] In another general aspect, the optical imaging system includes: a lens group including a plurality of lenses sequentially disposed along the optical axis; an optical path folding member disposed on the object side of the lens group, and a first reflecting member and a second reflecting member disposed between the optical path folding member and the lens group, each of the first reflecting member and the second reflecting member having a free-form surface, where 1.40 < f / fL < 1.80, where f is the focal length of the optical imaging system, and fL is the focal length of the lens group.

[0018] The optical imaging system may further include a third reflecting member disposed between the lens group and the imaging surface.

[0019] The ratio fm1 / f may be greater than 0.8 and less than 1.40, where fm1 is the focal length of the first reflecting member.

[0020] The ratio fm2 / f may be greater than -1.0 and less than -0.4, where fm2 is the focal length of the second reflecting member.

[0021] The absolute value of the ratio fm1 / fm2 may be greater than 1.40 and less than 1.80.

[0022] The ratio TL / f may be greater than 0.40 and less than 0.9, where TL is the distance from the object side surface of the lens disposed at the foremost position of the lens group to the imaging surface.

[0023] In another general aspect, the optical imaging system includes a reflecting element disposed between the lens group and the optical path folding member, the optical path folding member configured to bend the optical path between the optical path folding member and the lens group, where the reflecting element includes a first reflecting member having a positive refractive power, and where the lens group includes a first lens having a positive refractive power.

[0024] The reflecting element may further include a second reflecting member having a negative refractive power. The lens group may further include a second lens having a negative refractive power.

[0025] Other features and aspects will become apparent from the following detailed description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a diagram showing an optical imaging system according to a first example.

[0027] Figure 2 is a diagram showing distortion aberration of the optical imaging system according to the first example.

[0028] Figure 3 is a diagram showing an optical imaging system according to a second example.

[0029] Figure 4 is a diagram showing distortion aberration of the optical imaging system according to the second example.

[0030] Figure 5 is a diagram showing an optical imaging system according to a third example.

[0031] Figure 6 is a diagram showing distortion aberration of the optical imaging system according to the third example.

[0032] Throughout the drawings and detailed description, 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 sizes, proportions, and depictions of elements in the drawings may be exaggerated. DETAILED DESCRIPTION

[0033] Hereinafter, although examples of the present disclosure will be described in detail with reference to the accompanying drawings, it should be noted that the examples are not limited thereto.

[0034] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described in this application. However, various changes, modifications and equivalents of the methods, devices and / or systems described in this application will be apparent after understanding the present disclosure. For example, the order of operations described in this application is merely an example, and except for operations that must occur in a specific order, it is not limited to the order set forth in this application, but can be changed, which will be apparent after understanding the present disclosure. In addition, for greater clarity and brevity, the description of the functions and structures that will be known in the art may be omitted.

[0035] The features described in this application can be implemented in different forms and should not be understood as being limited to the examples described in this application. Rather, the examples described in this application are provided only to illustrate some of the many possible ways to implement the methods, devices and / or systems described in this application that will be apparent after understanding this disclosure.

[0036] It should be noted that in this application, the use of the word "may" with respect to examples or embodiments, for example, regarding what an example or embodiment may include or implement, means that there is at least one example or embodiment that includes or implements such features, and all examples and embodiments are not limited thereto.

[0037] Throughout the specification, when an element such as a layer, region, or substrate is described as being "on," "connected to," or "coupled to" another element, the element may be directly "on," "connected to," or "coupled 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 coupled to" another element, there are no other elements between the element and the other element. As used in this application, a "portion" of an element may include the entire element or less than the entire element.

[0038] As used in this application, the term "and / or" includes any one of the associated listed items and any combination of any two or more items; similarly, "at least one" includes any one of the associated listed items and any combination of any two or more items.

[0039] Although the terms "first", "second" and "third" may be used in this application to describe various members, components, regions, layers or parts, these members, components, regions, layers or parts are not limited by these terms. More specifically, these terms are only used to distinguish one member, component, region, layer or part from another member, component, region, layer or part. Therefore, without departing from the teachings of the examples described in this application, the first member, first component, first region, first layer or first part mentioned in these examples may also be referred to as the second member, second component, second region, second layer or second part.

[0040] Spatially relative terms such as "above", "higher", "below", "lower", etc. may be used in this application for descriptive convenience to describe the relationship of one element relative to another element as shown in the accompanying drawings. In addition to covering the orientations depicted in the accompanying drawings, these spatially relative terms are intended to also cover different orientations of the device in use or operation. For example, if the device in the accompanying drawings is flipped, an element described as being "above" or "higher" relative to another element will be "below" or "lower" relative to the other element. Therefore, 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 spatially relative terms used in this application should be interpreted accordingly.

[0041] The terms used in this application are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the articles "a", "an" and "the" are intended to also include plural forms. The words "include", "comprise" and "have" indicate the presence of the features, numbers, operations, components, elements and / or their combinations, but do not exclude the presence or addition of one or more other features, numbers, operations, components, elements and / or their combinations.

[0042] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described in the present application are not limited to the specific shapes shown in the drawings, but include variations in shapes that occur during manufacturing.

[0043] Features of the examples described in this application may be combined in various ways that will be apparent after understanding the present disclosure. In addition, although the examples described in this application have various configurations, other configurations that will be apparent after understanding the present disclosure are also possible.

[0044] One aspect of the present disclosure is to provide an optical imaging system that can perform long-distance image capture and can allow a camera module to be miniaturized.

[0045] The optical imaging system includes a plurality of lenses arranged along an optical axis. The plurality of lenses may be spaced apart from each other by a predetermined distance along the optical axis.

[0046] For example, the optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, which are arranged in ascending numerical order along the optical axis from the object side of the optical imaging system toward the imaging plane of the optical imaging system, wherein the first lens is closest to the object side of the optical imaging system and the fifth lens is closest to the imaging plane.

[0047] In each lens, the object-side or first surface is the surface of the lens closest to the object side of the optical imaging system, and the image-side or second surface is the surface of the lens closest to the imaging plane.

[0048] Unless otherwise specified, reference to the shape of a lens surface refers to the shape of a paraxial region of the lens surface. The paraxial region of the lens surface is a 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 of sinθ≈θ, tanθ≈θ, and cosθ≈θ are valid.

[0049] In the example, the first lens refers to the lens closest to the object (or subject), and the fifth lens refers to the lens closest to the imaging plane (or image sensor). In the example, the units of the radius of curvature, thickness, TL (the distance from the object side of the first lens (or the front lens) to the imaging plane), IMGHT (half the diagonal length of the imaging plane), and focal length are expressed in millimeters (mm). The thickness of the lens, the gap between the lenses, and TL refer to the distance of the lenses on the optical axis. In addition, in the description of the shape of the lens, a configuration in which one face is convex indicates that the optical axis area of ​​the face is convex, and a configuration in which one face is concave indicates that the optical axis area of ​​the face is concave. Therefore, even when one face of the lens is described as convex, the edge of the lens may be concave. Similarly, even when one face of the lens is described as concave, the edge of the lens may be convex.

[0050] The optical imaging system according to the present disclosure may use a non-rotationally symmetric reflective member to adjust the light aberration of the light reaching the image sensor.For example, the optical imaging system may include a reflective member having a free-form curved surface.

[0051] The optical imaging system according to the example described in the present application can be installed on a camera module for a portable terminal device. However, the application scope of the optical imaging system is not limited to the camera module for a portable terminal device. In addition, the optical imaging system according to the example described in the present application can be selectively applied to multiple camera modules. As an example, the optical imaging system can be applied to one camera module among two or more camera modules installed on a portable terminal device. As another example, the optical imaging system according to the example described in the present application can be applied to one or more camera modules among three or more camera modules installed on a portable terminal device.

[0052] Hereinafter, an optical imaging system according to one or more examples will be described.

[0053] The optical imaging system according to the example may include a plurality of lenses and a plurality of reflective components. For example, the optical imaging system may include a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence from the object side. In addition, the optical imaging system may include a first reflective component and a second reflective component. The first reflective component and the second reflective component may be arranged closer to the object than the first lens to the fifth lens. For example, the first reflective component and the second reflective component may be arranged on the object side of the first lens. The first reflective component and the second reflective component may be configured to facilitate aberration correction. For example, the first reflective component and the second reflective component may be formed to have a free-form surface.

[0054] Each of the first reflective member and the second reflective member may be configured to have a refractive power. For example, the first reflective member may have a positive refractive power because its reflective surface is formed concave, and the second reflective member may have a negative refractive power because its reflective surface is formed convex.

[0055] The optical imaging system according to the example may further include an optical path folding member. The optical path folding member may be disposed on the object side of the first reflective member. The optical path folding member may be configured in the form of a prism, a reflective mirror, etc.

[0056] According to another example, an optical imaging system may include a lens group, an optical path folding member, and a reflective element. The lens group may include a plurality of lenses. For example, the lens group may include two or more lenses sequentially arranged along the optical axis. The lens group may establish a predetermined numerical relationship with the optical imaging system. For example, the ratio (f / fL) of the focal length f of the optical imaging system to the focal length fL of the lens group may be greater than 1.40 to less than 1.80. The optical path folding member may be arranged on the object side of the lens group, and may be configured to bend the optical path between the object and the lens group. The optical path folding member may be in the form of a prism. The reflective element may include a plurality of reflective members. For example, the reflective element may include a first reflective member and a second reflective member. The reflective element may be configured to have a free-form surface. For example, the reflective surface of the first reflective member and the reflective surface of the second reflective member may be formed as free-form surfaces, respectively.

[0057] Hereinafter, features of a reflective member and a lens constituting the optical imaging system according to the present disclosure will be described.

[0058] Each of the first reflective member and the second reflective member may be formed to have a curved surface. For example, the first reflective member may have a concave shape, and the second reflective member may have a convex shape.

[0059] The first lens may have a refractive power. One surface of the first lens may be convex. For example, the first lens may have a convex object side surface. The first lens may have an aspherical surface. For example, both surfaces of the first lens may be aspherical. The first lens may have a predetermined refractive index. For example, the refractive index of the first lens may be 1.5 or greater to less than 1.6.

[0060] The second lens may have a refractive power. One surface of the second lens may be concave. For example, the second lens may have a concave object-side surface. The second lens may have an aspherical surface. For example, both surfaces of the second lens may be aspherical. The second lens may have a predetermined refractive index. For example, the refractive index of the second lens may be 1.6 or greater to less than 1.7.

[0061] The third lens may have a refractive power. One surface of the third lens may be convex. For example, the third lens may have a convex object side surface. The third lens may have an aspherical surface. For example, two surfaces of the third lens may be aspherical. The third lens may have a predetermined refractive index. For example, the refractive index of the third lens may be 1.6 or greater to less than 1.7. The third lens may have a predetermined Abbe number. For example, the Abbe number of the third lens may be 15 or greater to less than 20.

[0062] The fourth lens may have a refractive power. One surface of the fourth lens may be convex. For example, the fourth lens may have a convex object side surface. The fourth lens may have an aspherical surface. For example, two surfaces of the fourth lens may be aspherical. The fourth lens may have a predetermined refractive index. For example, the refractive index of the fourth lens may be 1.6 or greater to less than 1.7.

[0063] The fifth lens may have a refractive power. One surface of the fifth lens may be concave. For example, the fifth lens may have a concave object-side surface. The fifth lens may have an aspherical surface. For example, both surfaces of the fifth lens may be aspherical. The fifth lens may have a predetermined refractive index. For example, the refractive index of the fifth lens may be 1.5 or greater to less than 1.6.

[0064] The lens constituting the optical imaging system is formed of a material having a refractive index different from that of air. For example, the lens may be formed of a plastic material or a glass material. As described above, each of the first to fifth lenses may have an aspherical surface. The aspherical surface of the lens may be represented by the following equation 1:

[0065] (Equation 1)

[0066]

[0067] In Equation 1, "c" is the inverse of the radius of curvature of each lens, "k" is the cone constant, "r" is the distance from a point on the aspherical surface of the lens to the optical axis, "A" to "H" and "J" are aspherical constants, and "Z" (or SAG) is the height from a point on the aspherical surface to the vertex of the aspherical surface in the optical axis direction.

[0068] The optical imaging system may also include filters, apertures and image sensors.

[0069] The filter may be disposed between the image sensor and a lens disposed closest to the image surface of the image sensor. The filter may block some wavelengths of incident light to improve the resolution of the optical imaging system. For example, the filter may block infrared wavelengths of incident light. The image sensor may be configured to convert an optical signal (optical image) into an electrical signal. The image surface of the image sensor may form an imaging surface disposed at the imaging surface of the optical imaging system.

[0070] If necessary, the optical imaging system may further include a third reflective member.

[0071] The third reflective member may be disposed between the lens group and the image sensor. For example, the third reflective member may be disposed between the image sensor and the fifth lens disposed closest to the image surface to bend the optical path between the fifth lens and the image sensor.

[0072] The optical imaging system may satisfy one or more of the following conditional expressions.

[0073] 0.40 <TL / f<0.90

[0074] 1.40 <f / fL<1.80

[0075] 0.70 <f / fm1<1.40

[0076] -3.0 <f / fm2<-1.0

[0077] 0.4 <fL / fm1<0.8

[0078] -1.6 <fL / fm2<-0.4

[0079] 4.0 <f / f1<8.0

[0080] -6.0 <f / f2<-3.0

[0081] 1.20 <f / f3<2.0

[0082] -1.0 <f / f4<2.0

[0083] -8.0 <f / f5<-2.0

[0084] 1.0 <f / f12<1.80

[0085] -3.0 <f / f345<3.0

[0086] 0.8 <fm1 / f<1.40

[0087] -1.0 <fm2 / f<-0.40

[0088] In the above conditional expressions, TL is the distance from the object side surface of the first lens to the imaging surface, f is the focal length of the optical imaging system, fL is the focal length of the lens group, fm1 is the focal length of the first reflecting member, fm2 is the focal length of the second reflecting member, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, and f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f12 is the combined focal length of the first lens and the second lens, and f345 is the combined focal length of the third lens to the fifth lens.

[0089] In the following description, various examples of optical imaging systems will be described.

[0090] In the following, reference will be made to Figure 1 An optical imaging system 100 according to a first example is described.

[0091] The optical imaging system 100 may include an optical path folding member P, a reflective element M, and a lens group 102 .

[0092] The optical path folding member P can be set at the frontmost position of the optical imaging system 100. The optical path folding member P can be configured to bend the path of light incident on the optical imaging system 100. For example, the optical path folding member P can refract or reflect the path of light incident along the optical path OP in the direction of the first optical axis C1 intersecting the optical path OP. In the drawings indicating the optical path OP, the optical path OP can be in the observation direction and is therefore represented by a dot. The optical path folding member P can be configured in the form of a prism. However, the shape of the optical path folding member P is not limited to a prism. For example, the optical path folding member P can be configured in the form of a reflector.

[0093] The reflective element M may be disposed between the optical path folding member P and the lens group 102. The reflective element M may bend the optical path between the optical path folding member P and the lens group 102 to reduce the external size of the optical imaging system 100. The reflective element M may include a first reflective member M1 and a second reflective member M2.

[0094] The first reflective member M1 may be configured to reflect light emitted from the optical path folding member P to the second reflective member M2. For example, the first reflective member M1 may reflect light incident along the first optical axis C1 in the direction of the second optical axis C2. The first reflective member M1 may be formed to have a curved shape. For example, the reflective surface of the first reflective member M1 may be concave. The first reflective member M1 may have a free-form surface. For example, at least a portion of the reflective surface of the first reflective member M1 may be formed as a free-form surface. The first reflective member M1 may have a predetermined refractive power. For example, the first reflective member M1 may have a positive refractive power.

[0095] The second reflective member M2 may be configured to reflect light incident from the first reflective member M1 to the lens group 102. For example, the second reflective member M2 may reflect light incident along the second optical axis C2 in the direction of the third optical axis C3. The second reflective member M2 may be formed to have a curved shape. For example, the reflective surface of the second reflective member M2 may be convex. The second reflective member M2 may have a free-form surface. For example, at least a portion of the reflective surface of the second reflective member M2 may be formed as a free-form surface. The second reflective member M2 may have a predetermined refractive power. For example, the second reflective member M2 may have a negative refractive power.

[0096] The lens group 102 may include a plurality of lenses. For example, the lens group 102 may include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, and a fifth lens 150 sequentially disposed along the third optical axis C3.

[0097] The first lens 110 may have positive refractive power. The first lens 110 may have a convex object side surface and a convex image side surface. The second lens 120 may have negative refractive power. The second lens 120 may have a concave object side surface and a concave image side surface. The third lens 130 may have positive refractive power. The third lens 130 may have a convex object side surface and a concave image side surface. The fourth lens 140 may have positive refractive power. The fourth lens 140 may have a convex object side surface and a concave image side surface. The fifth lens 150 may have negative refractive power. The fifth lens 150 may have a concave object side surface and a concave image side surface. An inflection point may be formed on the image side surface of the fifth lens 150.

[0098] The optical imaging system 100 includes an optical filter IF and an image sensor IP.

[0099] The filter IF may be disposed in front of the image sensor IP to block infrared rays, etc. included in the incident light. The image sensor IP may include a plurality of optical sensors. The above-mentioned image sensor IP may be configured to convert an optical signal into an electrical signal.

[0100] Table 1 lists the lens properties of the optical imaging system 100 according to the first example, Table 2 lists the asphericity values ​​of the optical imaging system 100 according to the first example, and Figure 2 is a diagram showing aberration curves of the optical imaging system 100 according to the first example.

[0101] Table 1

[0102] Face number mark Radius of curvature Thickness / distance Refractive Index Abbe number S1 Prism infinity 2.6300 1.722 29.500 S2 infinity 2.6300 S3 infinity 6.6400 S4 The first reflecting member -54.773 5.9550 1.298 100.000 S5 infinity 5.9550 S6 The second reflecting member 31.33 5.0000 1.298 100.000 S7 infinity 1.5000 S8 First lens 4.906 2.4380 1.534 55.650 S9 -5.836 0.0330 S10 Second lens -7.205 0.2000 1.615 25.960 S11 8.443 1.4380 S12 The third lens 4.836 0.5000 1.670 19.240 S13 6.676 2.9800 S14 The fourth lens 12.42 0.3000 1.615 25.960 S15 162.239 1.6290 S16 Fifth lens -3.314 0.4090 1.544 56.110 S17 6.503 1.4950 S18 Optical Filters infinity 0.2800 1.519 64.200 S19 infinity 1.7970 S20 Imaging surface infinity -0.0020

[0103] Table 2

[0104]

[0105]

[0106] In the following, reference will be made to Figure 3 An optical imaging system 200 according to a second example is described.

[0107] The optical imaging system 200 may include an optical path folding member P, a reflective element M, and a lens group 202 .

[0108] The optical path folding member P may be disposed at the foremost position of the optical imaging system 200. The optical path folding member P may be configured to bend the path of light incident to the optical imaging system 200. For example, the optical path folding member P may refract or reflect the path of light incident along the optical path OP in the direction of a first optical axis C1 intersecting the optical path OP. The optical path folding member P may be configured in the form of a prism. However, the shape of the optical path folding member P is not limited to a prism. For example, the optical path folding member P may be configured in the form of a reflector.

[0109] The reflective element M may be disposed between the optical path folding member P and the lens group 202. The reflective element M may bend the optical path between the optical path folding member P and the lens group 202 to reduce the external size of the optical imaging system 200. The reflective element M may include a first reflective member M1 and a second reflective member M2.

[0110] The first reflective member M1 may be configured to reflect light emitted from the optical path folding member P to the second reflective member M2. For example, the first reflective member M1 may reflect light incident along the first optical axis C1 in the direction of the second optical axis C2. The first reflective member M1 may be formed to have a curved shape. For example, the reflective surface of the first reflective member M1 may be concave. The first reflective member M1 may have a free-form surface. For example, at least a portion of the reflective surface of the first reflective member M1 may be formed as a free-form surface. The first reflective member M1 may have a predetermined refractive power. For example, the first reflective member M1 may have a positive refractive power.

[0111] The second reflective member M2 may be configured to reflect light incident from the first reflective member M1 to the lens group 202. For example, the second reflective member M2 may reflect light incident along the second optical axis C2 in the direction of the third optical axis C3. The second reflective member M2 may be formed to have a curved shape. For example, the reflective surface of the second reflective member M2 may be convex. The second reflective member M2 may have a free-form surface. For example, at least a portion of the reflective surface of the second reflective member M2 may be formed as a free-form surface. The second reflective member M2 may have a predetermined refractive power. For example, the second reflective member M2 may have a negative refractive power.

[0112] The lens group 202 may include a plurality of lenses. For example, the lens group 202 includes a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, and a fifth lens 250 sequentially disposed along the third optical axis C3.

[0113] The first lens 210 may have positive refractive power. The first lens 210 may have a convex object side surface and a convex image side surface. The second lens 220 may have negative refractive power. The second lens 220 may have a concave object side surface and a concave image side surface. The third lens 230 may have positive refractive power. The third lens 230 may have a convex object side surface and a concave image side surface. The fourth lens 240 may have negative refractive power. The fourth lens 240 may have a convex object side surface and a concave image side surface. The fifth lens 250 may have negative refractive power. The fifth lens 250 may have a concave object side surface and a convex image side surface. An inflection point may be formed on the image side surface of the fifth lens 250.

[0114] The optical imaging system 200 may include an optical filter IF and an image sensor IP.

[0115] The filter IF may be disposed in front of the image sensor IP to block infrared rays, etc. included in the incident light. The image sensor IP may include a plurality of optical sensors. The above-mentioned image sensor IP may be configured to convert an optical signal into an electrical signal.

[0116] Table 3 lists the lens properties of the optical imaging system 200 according to the second example, Table 4 lists the asphericity values ​​of the optical imaging system 200 according to the second example, and Figure 4 is a diagram showing aberration curves of the optical imaging system 200 according to the second example.

[0117] Table 3

[0118]

[0119]

[0120] Table 4

[0121] Face number S8 S9 S10 S11 S12 k 0.6859399 0 0 0 0 A 0.0004901 0.0001193 -0.0043659 -0.0041689 -0.0009391 B -0.0000117 0.0006860 0.0015988 0.0012015 0.0004363 C -0.0000058 -0.0001415 -0.0003086 -0.0002737 -0.0001074 D 0.0000022 0.0000121 0.0000267 0.0000273 0.0000107 E -0.0000002 -0.0000004 -0.0000008 -0.0000010 -0.0000004 Face number S13 S14 S15 S16 S17 k 0 0 0 0 0 A -0.00212730 -0.01136750 -0.00631775 -0.01175663 -0.00927392 B 0.00042022 0.00024121 0.00106880 0.01196813 0.00189419 C -0.00008452 0.00093314 0.00065764 -0.00453065 -0.00012979 D 0.00000748 -0.00030695 -0.00024974 0.00080815 -0.00005190 E -0.00000020 0.00003100 0.00002886 -0.00005476 0.00000706

[0122] In the following, reference will be made to Figure 5 An optical imaging system 300 according to a third example is described.

[0123] The optical imaging system 300 may include an optical path folding member P, a reflective element M, and a lens group 302 .

[0124] The optical path folding member P may be disposed at the frontmost position of the optical imaging system 300. The optical path folding member P may be configured to bend the path of light incident to the optical imaging system 300. For example, the optical path folding member P may refract or reflect the path of light incident along the optical path OP in the direction of a first optical axis C1 intersecting the optical path OP. The optical path folding member P may be configured in the form of a prism. However, the shape of the optical path folding member P is not limited to a prism. For example, the optical path folding member P may be configured in the form of a reflector.

[0125] The reflective element M may be disposed between the optical path folding member P and the lens group 302. The reflective element M may bend the optical path between the optical path folding member P and the lens group 302 to reduce the external size of the optical imaging system 300. The reflective element M may include a first reflective member M1 and a second reflective member M2.

[0126] The first reflective member M1 may be configured to reflect light emitted from the optical path folding member P to the second reflective member M2. For example, the first reflective member M1 may reflect light incident along the first optical axis C1 in the direction of the second optical axis C2. The first reflective member M1 may be formed to have a curved shape. For example, the reflective surface of the first reflective member M1 may be concave. The first reflective member M1 may include a free-form surface. For example, at least a portion of the reflective surface of the first reflective member M1 may be formed as a free-form surface. The first reflective member M1 may have a predetermined refractive power. For example, the first reflective member M1 may have a positive refractive power.

[0127] The second reflective member M2 may be configured to reflect light incident from the first reflective member M1 to the lens group 302. For example, the second reflective member M2 may reflect light incident along the second optical axis C2 in the direction of the third optical axis C3. The second reflective member M2 may be formed to have a curved shape. For example, the reflective surface of the second reflective member M2 may be convex. The second reflective member M2 may have a free-form surface. For example, at least a portion of the reflective surface of the second reflective member M2 may be formed as a free-form surface. The second reflective member M2 may have a predetermined refractive power. For example, the second reflective member M2 may have a negative refractive power.

[0128] The lens group 302 may include a plurality of lenses. For example, the lens group 302 includes a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, and a fifth lens 350 sequentially disposed along the third optical axis C3.

[0129] The first lens 310 may have positive refractive power. The first lens 310 may have a convex object side surface and a convex image side surface. The second lens 320 may have negative refractive power. The second lens 320 may have a concave object side surface and a concave image side surface. The third lens 330 may have positive refractive power. The third lens 330 may have a convex object side surface and a concave image side surface. The fourth lens 340 may have positive refractive power. The fourth lens 340 may have a convex object side surface and a concave image side surface. The fifth lens 350 may have negative refractive power. The fifth lens 350 may have a concave object side surface and a concave image side surface. An inflection point may be formed on the image side surface of the fifth lens 350.

[0130] The optical imaging system 300 may further include a third reflective member M3. The third reflective member M3 may be disposed between the fifth lens 350 disposed on the rear side of the lens group 302 and the image sensor IP to bend the optical path. For example, the third reflective member M3 may reflect light incident along the third optical axis C3 in the direction of the fourth optical axis C4.

[0131] The optical imaging system 300 may include an optical filter IF and an image sensor IP.

[0132] The filter IF may be disposed in front of the image sensor IP to block infrared rays, etc. included in the incident light. The image sensor IP may include a plurality of optical sensors. The above-mentioned image sensor IP may be configured to convert an optical signal into an electrical signal.

[0133] Table 5 lists the lens characteristics of the optical imaging system 300 according to the third example, Table 6 lists the aspheric surface values ​​of the optical imaging system 300 according to the third example, and Figure 6 is a diagram showing aberration curves of the optical imaging system 300 according to the third example.

[0134] Table 5

[0135] Face number mark Radius of curvature Thickness / distance Refractive Index Abbe number S1 Prism infinity 2.6300 1.722 29.500 S2 infinity 2.6300 S3 infinity 4.8271 S4 The first reflecting member -61.383 5.8405 1.298 100.000 S5 infinity 5.8405 S6 The second reflecting member 37.975 5.0000 1.298 100.000 S7 infinity 1.5000 S8 First lens 5.009 2.4279 1.534 55.650 S9 -6.038 0.0300 S10 Second lens -7.601 0.2500 1.615 25.960 S11 6.79 1.7548 S12 The third lens 5.673 0.5525 1.670 19.240 S13 10.37 2.9827 S14 The fourth lens 18.246 0.4442 1.615 25.960 S15 115.25 1.5579 S16 Fifth lens -3.714 0.2000 1.544 56.110 S17 117.467 3.4949 S18 The third reflecting member infinity 6.2302 S19 Optical Filters infinity 0.2800 1.519 64.200 S20 infinity 4.4694 S21 Imaging surface infinity -0.0021

[0136] Table 6

[0137]

[0138]

[0139] Optical characteristics and conditional expression values ​​of the optical imaging systems according to the first to third examples are listed in Tables 7 and 8.

[0140] Table 7

[0141] mark First example Second example Third Example fm1 27.3800 33.0500 30.6900 fm2 -15.6600 -20.0900 -18.9900 f1 5.4170 5.119 5.5488 f2 -6.2905 -4.9711 -5.7930 f3 23.5878 12.7891 17.8336 f4 21.8528 -76.918 35.1874 f5 -3.9764 -10.1294 -6.6135 TL 13.5010 13.4864 24.6724 f 31.6000 25.0000 30.0000 f 18.4600 15.2000 18.5450

[0142] Table 8

[0143] Conditional Expressions First example Second example Third Example TL / f 0.42725 0.53946 0.82241 f / fL 1.71181 1.64474 1.61769 f / fm1 1.15413 0.75643 0.97752 f / fm2 -2.01788 -1.24440 -1.57978 fL / fm1 0.67421 0.45991 0.60427 fL / fm2 -1.17880 -0.75660 -0.97657 |fm1 / fm2| 1.74840 1.64510 1.61611 f / f1 5.8335 4.8838 5.4066 f / f2 -5.0234 -5.0291 -5.1787 f / f3 1.3397 1.9548 1.6822 f / f4 1.4460 -0.3250 0.8526 f / f5 -7.9469 -2.4681 -4.5362 f / f12 1.75100 1.22400 1.19200 f / f345 -2.81800 2.58160 -0.54800 fm1 / f 0.86646 1.32200 1.02300 fm2 / f -0.49557 -0.80360 -0.63300

[0144] As described above, images of distant objects can be captured, and the camera module can be miniaturized.

[0145] Although specific examples have been shown and described above, it will be apparent after understanding the present 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 examples described in this application should be understood in a descriptive sense only, and not for limiting purposes. The description of the features or aspects in each example should be understood to be applicable to similar features or aspects in other examples. If the described techniques are performed in a different order, and / or if the components in the described systems, architectures, devices, or circuits are combined in different ways and / or replaced or supplemented by other components or their equivalents, appropriate results can still be achieved. Therefore, the scope of the present disclosure is not limited by 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 the present disclosure.

Claims

1. An optical imaging system, comprising: A lens group including a first lens having refractive power, a second lens having negative refractive power, a third lens having positive refractive power, a fourth lens having refractive power, and a fifth lens having negative refractive power, which are sequentially arranged from the object side; And A first reflecting member and a second reflecting member, which are disposed on the object side of the lens group and each have a free-form surface, Wherein, the first reflecting member has positive refractive power, and the second reflecting member has negative refractive power, Wherein, 4.0 < f / f1 < 8.0, where f is the focal length of the optical imaging system, and f1 is the focal length of the first lens, and Wherein, the lens group has a total of five lenses.

2. The optical imaging system according to claim 1, wherein: The first reflecting member has a concave reflecting surface.

3. The optical imaging system according to claim 1, wherein: The second reflecting member has a convex reflecting surface.

4. The optical imaging system according to claim 1, wherein: The first lens has a convex object side surface.

5. The optical imaging system according to claim 1, wherein: The second lens has a concave object side surface.

6. The optical imaging system according to claim 1, wherein: The third lens has a convex object side surface.

7. The optical imaging system according to claim 1, wherein: The fourth lens has a convex object side surface.

8. The optical imaging system according to claim 1, wherein: The fifth lens has a concave object side surface.

9. The optical imaging system according to claim 1, wherein, 1.40 < f / fL < 1.80, Where f is the focal length of the optical imaging system, and fL is the combined focal length of the first lens to the fifth lens.

10. An optical imaging system, comprising: A lens group including a first lens having refractive power, a second lens having negative refractive power, a third lens having positive refractive power, a fourth lens having refractive power, and a fifth lens having negative refractive power, which are sequentially arranged along the optical axis; An optical path folding member, which is disposed on the object side of the lens group; And A first reflecting member and a second reflecting member, which are disposed between the optical path folding member and the lens group and each have a free-form surface, Wherein, the first reflecting member has positive refractive power, and the second reflecting member has negative refractive power, Wherein, 1.40 < f / fL < 1.80 and 4.0 < f / f1 < 8.0, Where f is the focal length of the optical imaging system, fL is the focal length of the lens group, and f1 is the focal length of the first lens, and Wherein, the lens group has a total of five lenses.

11. The optical imaging system according to claim 10, further comprising: A third reflecting member, which is disposed between the lens group and the imaging surface.

12. The optical imaging system according to claim 10, wherein, 0.8 < fm1 / f < 1.40, Where fm1 is the focal length of the first reflecting member.

13. The optical imaging system according to claim 10, wherein, -1.0 < fm2 / f < -0.40, Where fm2 is the focal length of the second reflecting member.

14. The optical imaging system according to claim 10, wherein, 1.40 < |fm1 / fm2| < 1.80, Where fm1 is the focal length of the first reflecting member, and fm2 is the focal length of the second reflecting member.

15. The optical imaging system according to claim 10, wherein, 0.40 < TL / f < 0.9, Wherein, TL is the distance from the object side surface of the lens arranged at the frontmost position of the lens group to the imaging surface.

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