Optical imaging system

Abstract

An optical imaging system comprising: a first lens having positive refractive power; a second lens having positive refractive power; a third lens having negative refractive power; a fourth lens having refractive power; a fifth lens having positive refractive power; a sixth lens having refractive power; a seventh lens having positive refractive power; and an eighth lens having negative refractive power, wherein the first lens to the eighth lens are arranged in order from an object side, wherein the optical imaging system has a total of 8 lenses, wherein D12 / D_MAX < 0.15, wherein D12 is a distance on an optical axis between an image side surface of the first lens and an object side surface of the second lens, and D_MAX is a maximum distance among distances between adjacent lenses, and wherein (D12+D23) / D_SUM < 0.1, wherein D23 is a distance on an optical axis between an image side surface of the second lens and an object side surface of the third lens, and D_SUM is a sum of distances between each pair of adjacent lenses.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0127218, filed with the Korean Intellectual Property Office on September 29, 2020, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The following description relates to an optical imaging system. Background Technology

[0004] Portable terminals are equipped with cameras that include an optical imaging system consisting of multiple lenses to enable video calls and photography.

[0005] Furthermore, as the functionality of cameras in portable devices gradually increases, the demand for high-resolution cameras for portable devices is also increasing.

[0006] Furthermore, as portable devices become smaller, there is a growing demand for thinner cameras used in them.

[0007] Therefore, there is a need to develop a thin optical imaging system that can achieve high resolution. Summary of the Invention

[0008] The summary portion of this invention is intended to provide a brief overview of the chosen inventive concepts, which will be further described in the detailed description portion below. This summary portion is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0009] The example provides a slim optical imaging system that enables high resolution.

[0010] In general, 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 from the object side. The first and second lenses each have positive refractive power, and the third lens has negative refractive power, and all satisfy D12 / D_MAX < 0.15, where D12 is the distance along the optical axis between the image-side surface of the first lens and the object-side surface of the second lens, and D_MAX is the maximum distance between adjacent lenses.

[0011] The optical imaging system can satisfy (D12+D23) / D_SUM<0.1, where D23 is the distance along the optical axis between the image side of the second lens and the object side of the third lens, and D_SUM is the sum of the distances between each pair of adjacent lenses.

[0012] The optical imaging system can satisfy 0.9 < R2 / R3 < 1.1, where R2 is a radius of curvature of an image side surface of the first lens, and R3 is a radius of curvature of an object side surface of the second lens.

[0013] The optical imaging system can satisfy that the first lens has a meniscus shape convex toward an object side, and the second lens has a meniscus shape convex toward an object side.

[0014] The optical imaging system can satisfy D12 / f < 0.1, where f is a total focal length of the optical imaging system.

[0015] The optical imaging system can satisfy D67-D12-D23 > 0.2, where D23 is a distance along an optical axis between an image side surface of the second lens and an object side surface of the third lens, and D67 is a distance along the optical axis between an image side surface of the sixth lens and an object side surface of the seventh lens.

[0016] The optical imaging system can satisfy TTL / (2*IMG HT) < 0.8, where TTL is a distance along an optical axis from an object side surface of the first lens to an image plane, and IMG HT is half of a diagonal length of the image plane.

[0017] The optical imaging system can satisfy TTL / f < 1.2 and BFL / f < 0.3, where f is a total focal length of the optical imaging system, and BFL is a distance along an optical axis from an image side surface of the eighth lens to an image plane.

[0018] The optical imaging system can satisfy at least one of 25 < v1-v3 < 45, 25 < v1-v5 < 45, and 15 < v1-v6 < 25, where v1 is an Abbe number of the first lens, v3 is an Abbe number of the third lens, v5 is an Abbe number of the fifth lens, and v6 is an Abbe number of the sixth lens.

[0019] The fifth lens can have a negative refractive power, the sixth lens can have a positive refractive power or a negative refractive power, and the third lens, the fifth lens, and the sixth lens can each have a refractive index of 1.57 or more.

[0020] The third lens and the fifth lens can each have a refractive index of more than 1.64.

[0021] The optical imaging system can satisfy |f1 / f2| < 1, where f1 is a focal length of the first lens, and f2 is a focal length of the second lens.

[0022] The optical imaging system can satisfy 0 < f1 / f < 1.4, where f is a total focal length of the optical imaging system.

[0023] The optical imaging system can satisfy 5 < f2 / f < 50.

[0024] The fourth lens can have a positive refractive power or a negative refractive power, the fifth lens can have a negative refractive power, the sixth lens can have a positive refractive power or a negative refractive power, the seventh lens can have a positive refractive power, and the eighth lens can have a negative refractive power.

[0025] In one general aspect, an optical imaging system includes, in order from an object side, 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. The signs of refractive powers of the first and second lenses are different from the sign of the refractive power of the third lens, at least three of the third to eighth lenses each have a refractive index of 1.57 or more, and a condition (D12+D23) / D_SUM<0.1 is satisfied, where D12 is a distance along an optical axis between an image side surface of the first lens and an object side surface of the second lens, D23 is a distance along the optical axis between an image side surface of the second lens and an object side surface of the third lens, and D_SUM is a sum of distances between each pair of adjacent lenses.

[0026] Other features and aspects will become apparent from the following detailed description, drawings and claims. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a configuration diagram of an optical imaging system according to a first example.

[0028] Figure 2 is a configuration diagram of an optical imaging system according to a second example. Figure 1 is a graph showing aberration characteristics of the optical imaging system shown.

[0029] Figure 3 is a configuration diagram of an optical imaging system according to a third example.

[0030] Figure 4 is a configuration diagram of an optical imaging system according to a fourth example. Figure 3 is a graph showing aberration characteristics of the optical imaging system shown.

[0031] Figure 5 is a configuration diagram of an optical imaging system according to a third example.

[0032] Figure 6 is a graph showing aberration characteristics of the optical imaging system shown. Figure 5

[0033] Figure 7 is a configuration diagram of an optical imaging system according to a fourth example.

[0034] Figure 8 is a graph showing aberration characteristics of the optical imaging system shown. Figure 7

[0035] Figure 9 ​​is a configuration diagram of an optical imaging system according to the fifth example.

[0036] Figure 10 is a graph showing Figure 9 aberration characteristics of the optical imaging system shown.

[0037] In all of the drawings and specific embodiments, like reference numerals refer to like elements throughout. The drawings can not be to scale and the dimensions, proportions, and shapes of the components in the drawings can be exaggerated for clarity, illustration, and convenience. DETAILED DESCRIPTION

[0038] The following detailed description is presented to aid in understanding the method, apparatus and / or system described herein. Various changes, modifications, and equivalents can be used and will be apparent to those skilled in the art without departing from the scope of the method, apparatus and / or system described herein. The order in which operations are described is not necessarily the order in which they are performed and the operations can be combined or separated into other operations. Additionally, descriptions of functions and constructions that can be well known to one of ordinary skill in the art can be omitted in order to more clearly describe the subject matter of the present disclosure.

[0039] The features described herein can be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the described embodiments are to be considered in a descriptive sense only and not as a restrictive means. Descriptions of implementations should not be taken to limit the scope of the disclosure.

[0040] In this document, the use of the expression "can" (for example, with respect to an implementation or example can include or implement what) means that there is at least one implementation or example in which the feature is included or implemented, and that not all implementations and examples are limited to this.

[0041] Throughout the specification, when an element such as a layer, region, or substrate is referred to as being "on", "connected to", or "coupled to" another element, it can be directly on, directly connected to, or directly coupled to the other element, or one or more other elements can be interposed therebetween. Conversely, when an element is referred to as being "directly on", "directly connected to", or "directly coupled to" another element, there are no other elements interposed therebetween.

[0042] As used herein, the expression "and / or" includes any one of the associated listed items, as well as any combination of any two or more of the associated listed items.

[0043] Although terminology such as "first," "second," and "third" can be used herein to describe various components, parts, regions, layers or sections, such components, parts, regions, layers or sections are not limited by the terminology. Rather, the terminology is used to differentiate one component, part, region, layer or section from another component, part, region, layer or section. Thus, a first component, part, region, layer or section mentioned in an example can also be called a second component, part, region, layer or section without departing from the teachings of the examples described herein.

[0044] Spatially relative terms such as "on", "upper", "lower", "below", and "above" can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Such spatially relative terms can be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "on" or "upper" relative to other elements or features would then be oriented "below" or "lower" relative to the other elements or features. Accordingly, the expression "on" or "upper" can encompass both an orientation of above and below. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0045] The terminology used herein is for the purpose of describing various examples only and is not intended to be limiting of the disclosure. Unless otherwise defined, articles "a," "one" and "the" are intended to include plural references, the language of which is used only in the sense to provide that when there are two or more times the same part or component described in the examples of the disclosure. The terms "comprising," "comprises," and "including" when used herein, specify the presence of stated features, integers, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, operations, elements, components, and / or groups thereof.

[0046] The shapes shown in the drawings can vary due to manufacturing techniques and / or tolerances. Thus, the examples described herein are not limited to the specific shapes shown in the drawings, but include variations of the shapes that occur during manufacturing.

[0047] The features of the examples described herein can be combined in various ways without departing from the teachings of the disclosure. Furthermore, although the examples described herein have a variety of configurations, other configurations are possible in accordance with the teachings of the disclosure.

[0048] The accompanying drawings can not be drawn to scale, and the relative dimensions, proportions, and descriptions of the elements in the drawings can be exaggerated for clarity, illustration, and ease of understanding.

[0049] In the following configuration diagrams of the lens, the thickness, size, and shape of the lens are slightly exaggerated for description, and in detail, the shape of the spherical surface or aspherical surface suggested in the configuration diagram of the lens is presented by way of example, but is not limited thereto.

[0050] The optical imaging system according to an example includes at least 8 lenses.

[0051] The first lens can refer to the lens closest to the object side, and the last lens can refer to the lens closest to the image sensor.

[0052] Further, in each lens, the first surface (or object side surface) refers to the surface close to the object side, and the second surface (or image side surface) refers to the surface close to the image side. Further, in the present specification, the values of the radius of curvature, the thickness, the distance, and the focal length of the lens are all in mm, and the unit of the field of view (FOV) is degree.

[0053] Further, in the description of the shape of each lens, the meaning of the convex shape on one surface means that the paraxial region part of the surface is convex, and the meaning of the concave shape on one surface means that the paraxial region part of the surface is concave. The meaning of the flat surface of one surface means that the paraxial region part of the surface is flat.

[0054] Therefore, even in the case where one surface of the lens is described as convex, the edge part of the lens can be concave. Similarly, even in the case where one surface of the lens is described as concave, the edge part of the lens can be convex. Further, even in the case where one surface of the lens is described as a flat surface, the edge part of the lens can be convex or concave.

[0055] On the other hand, the paraxial region refers to a very narrow region near the optical axis.

[0056] The optical imaging system according to an example includes at least 8 lenses.

[0057] For example, the optical imaging system according to an example 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. The first lens to the eighth lens are spaced apart from each other by a predetermined distance along the optical axis.

[0058] The optical imaging system according to an example can include 9 or more lenses as needed.

[0059] The optical imaging system according to an example can further include an image sensor for converting an incident image of an object into an electrical signal.

[0060] In addition, the optical imaging system can further include an infrared filter (hereinafter, referred to as a "filter") for blocking infrared rays. The filter is disposed between the last lens and the image sensor.

[0061] In addition, the optical imaging system can further include a diaphragm for adjusting the amount of light.

[0062] The lenses constituting the optical imaging system according to the example can be formed of a plastic material.

[0063] In addition, all of the lenses have an aspherical surface. For example, each of the first lens to the eighth lens can have at least one aspherical surface.

[0064] For example, at least one of the first surface and the second surface of the first lens to the eighth lens can be aspherical. In this case, the aspherical surface of the first lens to the eighth lens is represented by Equation 1.

[0065] [Equation 1]

[0066]

[0067] In Equation 1, c is a curvature of the lens (an inverse of a radius of curvature), K is a conic constant, and Y is a distance from an arbitrary point on the aspherical surface of the lens to an optical axis. In addition, the constants A to P represent aspherical constants, and Z represents a distance along the optical axis from the arbitrary point on the aspherical surface of the lens to a vertex of the aspherical surface.

[0068] The optical imaging system including the first lens to the eighth lens can have, in order from the object side, positive power / positive power / negative power / positive power / negative power / negative power / positive power / negative power, or can have positive power / positive power / negative power / positive power / negative power / positive power / positive power / negative power, or can have positive power / positive power / negative power / negative power / negative power / positive power / positive power / negative power.

[0069] The optical imaging system according to the example can satisfy at least one of the following conditional expressions.

[0070] 0 < f1 / f < 1.4 [Conditional Expression 1]

[0071] 25 < v1-v3 < 45 [Conditional Expression 2]

[0072] 25 < v1-v5 < 45 [Conditional Expression 3]

[0073] 15 < v1-v6 < 25 [Conditional Expression 4]

[0074] 5 < f2 / f < 50 [Condition Expression 5]

[0075] -5 < f3 / f < 0 [Condition Expression 6]

[0076] |f4 / f| > 3 [Condition Expression 7]

[0077] -25 < f5 / f < 0 [Condition Expression 8]

[0078] f6 / f > 2 [Condition Expression 9]

[0079] f7 / f < 5 [Condition Expression 10]

[0080] TTL / f < 1.2 [Condition Expression 11]

[0081] |f1 / f2| < 1 [Condition Expression 12]

[0082] -2 < f1 / f3 < 0 [Condition Expression 13]

[0083] BFL / f < 0.3 [Condition Expression 14]

[0084] D12 / f < 0.1 [Condition Expression 15]

[0085] D67-D12-D23 > 0.2 [Condition Expression 16]

[0086] TTL / (2*IMG HT) < 0.8 [Condition Expression 17]

[0087] D12 / D_MAX < 0.15 [Condition Expression 18]

[0088] (D12+D23) / D_SUM < 0.1 [Condition Expression 19]

[0089] 0.9 < R2 / R3 < 1.1 [Condition Expression 20]

[0090] 70° < FOV < 92° [Condition Expression 21]

[0091] 1.5 < Fno < 2 [Condition Expression 22]

[0092] In the condition expressions 1 to 22, f is the total focal length of the optical imaging system, 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, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, and f7 is the focal length of the seventh lens.

[0093] v1 is an Abbe number of the first lens, v3 is an Abbe number of the third lens, and v5 is an Abbe number of the fifth lens.

[0094] TTL is a distance along the optical axis from an object side surface of a lens disposed closest to the object side (e.g., the first lens) to an imaging surface of the image sensor, and BFL is a distance along the optical axis from an image side surface of a lens disposed closest to the image sensor (e.g., the eighth lens) to the imaging surface of the image sensor.

[0095] D12 is a distance along the optical axis between the image side surface of the first lens and the object side surface of the second lens, D23 is a distance along the optical axis between the image side surface of the second lens and the object side surface of the third lens, and D67 is a distance along the optical axis between the image side surface of the sixth lens and the object side surface of the seventh lens.

[0096] D_MAX is the largest distance among the distances between adjacent lenses, D_SUM is the sum of the distances between adjacent lenses, R2 is a radius of curvature of the image side surface of the first lens, and R3 is a radius of curvature of the object side surface of the second lens.

[0097] IMG HT is half of a diagonal length of the imaging surface of the image sensor, FOV is an angle of view of the optical imaging system, and Fno is an F number of the optical imaging system.

[0098] The optical imaging system according to an example includes a first lens to an eighth lens.

[0099] The first lens has a positive refractive power. Further, the first lens can have a meniscus shape convex toward an object. In detail, a first surface of the first lens can be convex, and a second surface of the first lens can be concave.

[0100] At least one of the first surface and the second surface of the first lens can be an aspheric surface. For example, both surfaces of the first lens can be aspheric.

[0101] The second lens has a positive refractive power. Further, the second lens can have a meniscus shape convex toward an object. In detail, a first surface of the second lens can be convex, and a second surface of the second lens can have a concave shape.

[0102] At least one of the first surface and the second surface of the second lens can be an aspheric surface. For example, both surfaces of the second lens can be aspheric.

[0103] The third lens has a negative refractive power. Further, the third lens can have a meniscus shape convex toward an object. In detail, a first surface of the third lens can be convex, and a second surface of the third lens can have a concave shape.

[0104] At least one of the first and second surfaces of the third lens can be aspherical. For example, both surfaces of the third lens can be aspherical.

[0105] The fourth lens has a positive or negative refractive power. Also, the fourth lens can have a meniscus shape convex toward the image side. In detail, the first surface of the fourth lens can be concave, and the second surface of the fourth lens can be convex.

[0106] At least one of the first and second surfaces of the fourth lens can be an aspherical surface. For example, both surfaces of the fourth lens can be aspherical.

[0107] The fifth lens has a negative refractive power. Also, the fifth lens can have a meniscus shape convex toward the object side. In detail, the first surface of the fifth lens can be convex in the paraxial region, and the second surface of the fifth lens can be concave in the paraxial region.

[0108] At least one of the first and second surfaces of the fifth lens can be an aspherical surface. For example, both surfaces of the fifth lens can be aspherical.

[0109] At least one inflection point can be formed on at least one of the first and second surfaces of the fifth lens. For example, the first surface of the fifth lens can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the fifth lens can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0110] The sixth lens has a positive or negative refractive power. Also, the sixth lens can have a meniscus shape convex toward the object side. In detail, the first surface of the sixth lens can be convex in the paraxial region, and the second surface of the sixth lens can be concave in the paraxial region.

[0111] At least one of the first and second surfaces of the sixth lens can be an aspherical surface. For example, both surfaces of the sixth lens can be aspherical.

[0112] At least one inflection point can be formed on at least one of the first and second surfaces of the sixth lens. For example, the first surface of the sixth lens can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the sixth lens can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0113] The seventh lens has a positive refractive power. Also, the seventh lens can have a meniscus shape convex toward the object. In detail, the first surface of the seventh lens can be convex in the paraxial region, and the second surface of the seventh lens can be concave in the paraxial region.

[0114] At least one of the first surface and the second surface of the seventh lens can be an aspheric surface. For example, both surfaces of the seventh lens can be aspheric.

[0115] Also, at least one inflection point can be formed on at least one of the first surface and the second surface of the seventh lens. For example, the first surface of the seventh lens can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the seventh lens can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0116] The eighth lens has a negative refractive power. Also, the eighth lens can have a meniscus shape convex toward the object. In detail, the first surface of the eighth lens can be convex in the paraxial region, and the second surface of the eighth lens can be concave in the paraxial region.

[0117] At least one of the first surface and the second surface of the eighth lens can be an aspheric surface. For example, both surfaces of the eighth lens can be aspheric.

[0118] Also, at least one inflection point can be formed on at least one of the first surface and the second surface of the eighth lens. For example, the first surface of the eighth lens can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the eighth lens can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0119] The first lens and the second lens can be formed of plastic materials having the same optical properties, and the second lens and the third lens can be formed of plastic materials having different optical properties.

[0120] The distance between the first lens and the second lens and the distance between the second lens and the third lens can be configured to be relatively narrow. For example, among the distances between the adjacent lenses, the distance between the first lens and the second lens or the distance between the second lens and the third lens can be the narrowest.

[0121] For example, the distance between the first lens and the second lens can be less than 15% of the largest distance among the distances between the adjacent lenses.

[0122] For example, the sum of the distance between the first lens and the second lens and the distance between the second lens and the third lens can be less than 10% of the sum of the distances between the adjacent lenses.

[0123] The first lens and the second lens can have the same sign of refractive power. For example, both the first lens and the second lens can have a positive refractive power.

[0124] The sign of the refractive power of the first lens and the second lens can be different from the sign of the refractive power of the third lens. For example, both the first lens and the second lens can have a positive refractive power, and the third lens can have a negative refractive power.

[0125] The image-side surface of the first lens and the object-side surface of the second lens can have a shape convex in the same direction. For example, both the image-side surface of the first lens and the object-side surface of the second lens are convex toward the object.

[0126] The curvature radius of the image-side surface of the first lens and the curvature radius of the object-side surface of the second lens can be the same as or similar to each other. For example, the ratio of the curvature radius of the image-side surface of the first lens to the curvature radius of the object-side surface of the second lens can be between 0.9 and 1.1.

[0127] At least three lenses of the optical imaging system can have a refractive index of 1.57 or more. At least three lenses among the other lenses (e.g., the third lens to the eighth lens) excluding the first lens and the second lens can have a refractive index of 1.57 or more. For example, the third lens, the fifth lens, and the sixth lens can have a refractive index of 1.57 or more.

[0128] At least two of the at least three lenses can have a refractive index greater than 1.64. For example, the third lens and the fifth lens can have a refractive index greater than 1.64.

[0129] Among the first lens to the third lens, the lens having a negative refractive power can have a refractive index greater than 1.67. For example, the third lens can have a negative refractive power, and can have a refractive index greater than 1.67.

[0130] Reference will be made to Figure 1 and Figure 2 An optical imaging system according to a first example will be described.

[0131] The optical imaging system according to the first example includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, and an eighth lens 180, and can further include an aperture, a filter 190, and an image sensor 191.

[0132] Table 1 shows the characteristics (curvature radius, thickness of a lens or distance between lenses, refractive index, Abbe number, and focal length) of each lens.

[0133] [Table 1]

[0134] Surface Number Label Radius of Curvature Thickness or Distance Refractive Index Abbe Number Focal Length S1 First Lens 2.5375 0.9000 1.546 56.0 5.7645 S2 11.4349 0.0300 S3 Second Lens 11.4075 0.2800 1.546 56.0 135.5410 S4 13.3684 0.0734 S5 Third Lens 8.6590 0.2577 1.687 18.2 -13.6820 S6 4.4525 0.4416 S7 Fourth Lens -64.1541 0.3310 1.546 56.0 63.8798 S8 -22.6415 0.2513 S9 Fifth Lens 72.1996 0.3739 1.644 23.5 -44.3466 S10 20.4251 0.5468 S11 Sixth Lens 10.1493 0.4872 1.570 37.4 -97.2157 S12 8.4294 0.3843 S13 Seventh Lens 3.1689 0.6929 1.537 55.7 6.8588 S14 21.0604 0.6534 S15 Eighth Lens 5.8142 0.5388 1.537 55.7 -5.0932 S16 1.7990 0.3438 S17 Filter Infinity 0.2100 1.518 64.2 S18 Infinity 0.6900 S19 Imaging Surface Infinity

[0135] The total focal length f of the optical imaging system according to the first example is 6.3135 mm, the Fno is 1.78, the FOV is 78.5°, and the IMG HT is 5.264 mm.

[0136] In the first example, the first lens 110 has a positive refractive power, the first surface of the first lens 110 has a convex shape, and the second surface of the first lens 110 has a concave shape.

[0137] The second lens 120 has a positive refractive power, the first surface of the second lens 120 has a convex shape, and the second surface of the second lens 120 has a concave shape.

[0138] The third lens 130 has a negative refractive power, the first surface of the third lens 130 has a convex shape, and the second surface of the third lens 130 has a concave shape.

[0139] The fourth lens 140 has a positive refractive power, the first surface of the fourth lens 140 has a concave shape, and the second surface of the fourth lens 140 has a convex shape.

[0140] The fifth lens 150 has a negative refractive power, the first surface of the fifth lens 150 is convex in the paraxial region, and the second surface of the fifth lens 150 is concave in the paraxial region.

[0141] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the fifth lens 150. For example, the first surface of the fifth lens 150 can be convex in the paraxial region and concave in a portion other than the paraxial region. The second surface of the fifth lens 150 can be concave in the paraxial region and convex in a portion other than the paraxial region.

[0142] The sixth lens 160 has a negative refractive power, the first surface of the sixth lens 160 is convex in the paraxial region, and the second surface of the sixth lens 160 is concave in the paraxial region.

[0143] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the sixth lens 160. For example, the first surface of the sixth lens 160 can be convex in the paraxial region and concave in a portion other than the paraxial region. The second surface of the sixth lens 160 can be concave in the paraxial region and convex in a portion other than the paraxial region.

[0144] The seventh lens 170 has a positive refractive power, the first surface of the seventh lens 170 is convex in the paraxial region, and the second surface of the seventh lens 170 is concave in the paraxial region.

[0145] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the seventh lens 170. For example, the first surface of the seventh lens 170 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the seventh lens 170 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0146] The eighth lens 180 has a negative refractive power, the first surface of the eighth lens 180 is convex in the paraxial region, and the second surface of the eighth lens 180 is concave in the paraxial region.

[0147] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the eighth lens 180. For example, the first surface of the eighth lens 180 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the eighth lens 180 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0148] Each surface of the first lens 110 to the eighth lens 180 has an aspherical coefficient as shown in Table 2. For example, both the object side surface and the image side surface of the first lens 110 to the eighth lens 180 are aspherical.

[0149] [Table 2]

[0150]

[0151]

[0152] An optical imaging system according to a second example will be described with reference to Figure 3 and Figure 4 An optical imaging system according to a second example will be described with reference to

[0153] The optical imaging system according to the second example includes a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, a seventh lens 270, and an eighth lens 280, and can further include an aperture, a filter 290, and an image sensor 291.

[0154] Table 3 shows the characteristics (curvature radius, thickness of a lens or distance between lenses, refractive index, Abbe number, and focal length) of each lens.

[0155] [Table 3]

[0156]

[0157]

[0158] The total focal length f of the optical imaging system according to the second example is 6.317 mm, the Fno is 1.78, the FOV is 78.4°, and the IMG HT is 5.264 mm.

[0159] In the second example, the first lens 210 has a positive refractive power, the first surface of the first lens 210 has a convex shape, and the second surface of the first lens 210 has a concave shape.

[0160] The second lens 220 has a positive refractive power, the first surface of the second lens 220 has a convex shape, and the second surface of the second lens 220 has a concave shape.

[0161] The third lens 230 has a negative refractive power, the first surface of the third lens 230 has a convex shape, and the second surface of the third lens 230 has a concave shape.

[0162] The fourth lens 240 has a positive refractive power, the first surface of the fourth lens 240 has a concave shape, and the second surface of the fourth lens 240 has a convex shape.

[0163] The fifth lens 250 has a negative refractive power, the first surface of the fifth lens 250 is convex in the paraxial region, and the second surface of the fifth lens 250 is concave in the paraxial region.

[0164] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the fifth lens 250. For example, the first surface of the fifth lens 250 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. Further, the second surface of the fifth lens 250 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0165] The sixth lens 260 has a positive refractive power, the first surface of the sixth lens 260 is convex in the paraxial region, and the second surface of the sixth lens 260 is concave in the paraxial region.

[0166] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the sixth lens 260. For example, the first surface of the sixth lens 260 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. Further, the second surface of the sixth lens 260 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0167] The seventh lens 270 has a positive refractive power, the first surface of the seventh lens 270 is convex in the paraxial region, and the second surface of the seventh lens 270 is concave in the paraxial region.

[0168] Further, at least one inflection point is formed on at least one of the first and second surfaces of the seventh lens 270. For example, the first surface of the seventh lens 270 can be convex in the paraxial region and concave in a portion other than the paraxial region. The second surface of the seventh lens 270 can be concave in the paraxial region and convex in a portion other than the paraxial region.

[0169] The eighth lens 280 has a negative refractive power, the first surface of the eighth lens 280 is convex in the paraxial region, and the second surface of the eighth lens 280 is concave in the paraxial region.

[0170] Further, at least one inflection point is formed on at least one of the first and second surfaces of the eighth lens 280. For example, the first surface of the eighth lens 280 can be convex in the paraxial region and concave in a portion other than the paraxial region. The second surface of the eighth lens 280 can be concave in the paraxial region and convex in a portion other than the paraxial region.

[0171] Each surface of the first to eighth lenses 210 to 280 has an aspherical coefficient as shown in Table 4. For example, both the object side surface and the image side surface of the first to eighth lenses 210 to 280 are aspherical.

[0172] [Table 4]

[0173]

[0174]

[0175]

[0176] An optical imaging system according to a third example will be described with reference to Figure 5 and An optical imaging system according to a third example will be described with reference to Figure 6 An optical imaging system according to a third example will be described with reference to

[0177] The optical imaging system according to the third example includes a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, a seventh lens 370, and an eighth lens 380, and can further include an aperture, a filter 390, and an image sensor 391.

[0178] Table 5 shows the characteristics (radius of curvature, thickness of a lens or distance between lenses, refractive index, Abbe number, and focal length) of each lens.

[0179] [Table 5]

[0180]

[0181]

[0182] The total focal length f of the optical imaging system according to the third example is 6.3285 mm, the Fno is 1.83, the FOV is 78.4°, and the IMG HT is 5.264 mm.

[0183] In the third example, the first lens 310 has a positive refractive power, the first surface of the first lens 310 has a convex shape, and the second surface of the first lens 310 has a concave shape.

[0184] The second lens 320 has a positive refractive power, the first surface of the second lens 320 has a convex shape, and the second surface of the second lens 320 has a concave shape.

[0185] The third lens 330 has a negative refractive power, the first surface of the third lens 330 has a convex shape, and the second surface of the third lens 330 has a concave shape.

[0186] The fourth lens 340 has a positive refractive power, the first surface of the fourth lens 340 is concave, and the second surface of the fourth lens 340 is convex.

[0187] The fifth lens 350 has a negative refractive power, the first surface of the fifth lens 350 has a convex shape in the paraxial region, and the second surface of the fifth lens 350 has a concave shape in the paraxial region.

[0188] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the fifth lens 350. For example, the first surface of the fifth lens 350 can be convex in the paraxial region and concave in a portion other than the paraxial region. The second surface of the fifth lens 350 can be concave in the paraxial region and convex in a portion other than the paraxial region.

[0189] The sixth lens 360 has a negative refractive power, the first surface of the sixth lens 360 has a convex shape in the paraxial region, and the second surface of the sixth lens 360 has a concave shape in the paraxial region.

[0190] Further, at least one inflection point is formed on at least one of the first and second surfaces of the sixth lens 360. For example, the first surface of the sixth lens 360 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the sixth lens 360 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0191] The seventh lens 370 has a positive refractive power, the first surface of the seventh lens 370 has a convex shape in the paraxial region, and the second surface of the seventh lens 370 has a concave shape in the paraxial region.

[0192] Further, at least one inflection point is formed on at least one of the first and second surfaces of the seventh lens 370. For example, the first surface of the seventh lens 370 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the seventh lens 370 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0193] The eighth lens 380 has a negative refractive power, the first surface of the eighth lens 380 is convex in the paraxial region, and the second surface of the eighth lens 380 is concave in the paraxial region.

[0194] Further, at least one inflection point is formed on at least one of the first and second surfaces of the eighth lens 380. For example, the first surface of the eighth lens 380 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the eighth lens 380 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0195] Each surface of the first to eighth lenses 310 to 380 has an aspherical coefficient as shown in Table 6. For example, both the object side surface and the image side surface of the first to eighth lenses 310 to 380 are aspherical.

[0196] [Table 6]

[0197]

[0198]

[0199] An optical imaging system according to a fourth example will be described with reference to Figure 7 and Figure 8 An optical imaging system according to a fourth example will be described with reference to

[0200] The optical imaging system according to the fourth example includes a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, a seventh lens 470, and an eighth lens 480, and can further include an aperture, a filter 490, and an image sensor 491.

[0201] Table 7 shows the characteristics (radius of curvature, thickness of a lens or distance between lenses, refractive index, Abbe number, and focal length) of each lens.

[0202] [Table 7]

[0203] Surface Number Label Radius of Curvature Thickness or Distance Refractive Index Abbe Number Focal Length S1 First Lens 2.7305 0.9274 1.546 56.0 6.1841 S2 12.5387 0.0751 S3 Second Lens 12.2159 0.2810 1.546 56.0 128.6972 S4 14.6652 0.0842 S5 Third Lens 9.3025 0.2501 1.687 18.2 -14.5712 S6 4.7691 0.4505 S7 Fourth Lens -114.3982 0.3179 1.546 56.0 -489.9740 S8 -200.0000 0.2756 S9 Fifth Lens 26.7068 0.3809 1.667 20.4 -62.0890 S10 16.1429 0.5943 S11 Sixth Lens 9.8889 0.4997 1.570 37.4 56.1534 S12 14.0436 0.5365 S13 Seventh Lens 3.7344 0.8233 1.537 55.7 8.8084 S14 16.4203 0.7142 S15 Eighth Lens 5.6728 0.5085 1.537 55.7 -5.9073 S16 1.9699 0.3698 S17 Filter Infinity 0.1100 1.518 64.2 S18 Infinity 0.8430 S19 Imaging Surface Infinity 0.0000

[0204] The total focal length f of the optical imaging system according to the fourth example is 6.8256 mm, the Fno is 1.78, the FOV is 74.2°, and the IMG HT is 5.264 mm.

[0205] In the fourth example, the first lens 410 has a positive refractive power, the first surface of the first lens 410 is convex, and the second surface of the first lens 410 is concave.

[0206] The second lens 420 has a positive refractive power, the first surface of the second lens 420 has a convex shape, and the second surface of the second lens 420 has a concave shape.

[0207] The third lens 430 has a negative refractive power, the first surface of the third lens 430 has a convex shape, and the second surface of the third lens 430 has a concave shape.

[0208] The fourth lens 440 has a negative refractive power, the first surface of the fourth lens 440 has a concave shape, and the second surface of the fourth lens 440 has a convex shape.

[0209] The fifth lens 450 has a negative refractive power, the first surface of the fifth lens 450 is convex in the paraxial region, and the second surface of the fifth lens 450 is concave in the paraxial region.

[0210] Further, at least one inflection point is formed on at least one of the first and second surfaces of the fifth lens 450. For example, the first surface of the fifth lens 450 can be convex in the paraxial region and concave in a portion other than the paraxial region. The second surface of the fifth lens 450 can be concave in the paraxial region and convex in a portion other than the paraxial region.

[0211] The sixth lens 460 has a positive refractive power, the first surface of the sixth lens 460 has a convex shape in the paraxial region, and the second surface of the sixth lens 460 has a concave shape in the paraxial region.

[0212] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the sixth lens 460. For example, the first surface of the sixth lens 460 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the sixth lens 460 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0213] The seventh lens 470 has a positive refractive power, the first surface of the seventh lens 470 has a convex shape in the paraxial region, and the second surface of the seventh lens 470 has a concave shape in the paraxial region.

[0214] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the seventh lens 470. For example, the first surface of the seventh lens 470 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the seventh lens 470 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0215] The eighth lens 480 has a negative refractive power, the first surface of the eighth lens 480 has a convex shape in the paraxial region, and the second surface of the eighth lens 480 has a concave shape in the paraxial region.

[0216] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the eighth lens 480. For example, the first surface of the eighth lens 480 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the eighth lens 480 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0217] Each surface of the first lens 410 to the eighth lens 480 has an aspherical coefficient as shown in Table 8. For example, both the object side surface and the image side surface of the first lens 410 to the eighth lens 480 are aspherical.

[0218] [Table 8]

[0219]

[0220]

[0221] Reference will be made to Figure 9 and Figure 10An optical imaging system according to a fifth example is described.

[0222] The optical imaging system according to the fifth example includes a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560, a seventh lens 570, and an eighth lens 580, and can further include an aperture, a filter 590, and an image sensor 591.

[0223] Table 9 shows the characteristics (radius of curvature, thickness of a lens or distance between lenses, refractive index, Abbe number, and focal length) of each lens.

[0224] [Table 9]

[0225]

[0226]

[0227] The total focal length f of the optical imaging system according to the fifth example is 6.8873 mm, the Fno is 1.80, the FOV is 73.7°, and the IMG HT is 5.264 mm.

[0228] In the fifth example, the first lens 510 has a positive refractive power, the first surface of the first lens 510 is convex, and the second surface of the first lens 510 is concave.

[0229] The second lens 520 has a positive refractive power, the first surface of the second lens 520 has a convex shape, and the second surface of the second lens 520 has a concave shape.

[0230] The third lens 530 has a negative refractive power, the first surface of the third lens 530 has a convex shape, and the second surface of the third lens 530 has a concave shape.

[0231] The fourth lens 540 has a negative refractive power, the first surface of the fourth lens 540 has a concave shape, and the second surface of the fourth lens 540 has a convex shape.

[0232] The fifth lens 550 has a negative refractive power, the first surface of the fifth lens 550 is convex in the paraxial region, and the second surface of the fifth lens 550 is concave in the paraxial region.

[0233] Further, at least one inflection point is formed on at least one of the first and second surfaces of the fifth lens 550. For example, the first surface of the fifth lens 550 can be convex in the paraxial region and concave in a portion other than the paraxial region. The second surface of the fifth lens 550 can be concave in the paraxial region and convex in a portion other than the paraxial region.

[0234] The sixth lens 560 has a positive refractive power, the first surface of the sixth lens 560 has a convex shape in the paraxial region, and the second surface of the sixth lens 560 has a concave shape in the paraxial region.

[0235] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the sixth lens 560. For example, the first surface of the sixth lens 560 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the sixth lens 560 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0236] The seventh lens 570 has a positive refractive power, the first surface of the seventh lens 570 is convex in the paraxial region, and the second surface of the seventh lens 570 is concave in the paraxial region.

[0237] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the seventh lens 570. For example, the first surface of the seventh lens 570 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the seventh lens 570 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0238] The eighth lens 580 has a negative refractive power, the first surface of the eighth lens 580 is convex in the paraxial region, and the second surface of the eighth lens 580 is concave in the paraxial region.

[0239] Further, at least one inflection point is formed on at least one of the first surface and the second surface of the eighth lens 580. For example, the first surface of the eighth lens 580 can be convex in the paraxial region, and can be concave in a portion other than the paraxial region. The second surface of the eighth lens 580 can be concave in the paraxial region, and can be convex in a portion other than the paraxial region.

[0240] Each surface of the first lens 510 to the eighth lens 580 has an aspherical coefficient as shown in Table 10. For example, both the object side surface and the image side surface of the first lens 510 to the eighth lens 580 are aspherical.

[0241] [Table 10]

[0242]

[0243]

[0244] Table 11 shows values of conditional expressions of the optical imaging system according to various examples.

[0245] [Table 11]

[0246]

[0247]

[0248] As described above, in the optical imaging system according to the examples, the size can be reduced while achieving a relatively high resolution.

[0249] While the present disclosure includes specific examples, it will be apparent to one of ordinary skill in the art, upon reading this disclosure, that various changes in form and detail can be made without departing from the spirit and scope of the claims and their equivalents. The examples described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each example should be considered as being applicable to similar features or aspects in other examples. Suitable results can be achieved if the described techniques are performed in a different order, and / or if the described systems, architectures, devices, or circuits are combined or substituted with other systems, architectures, devices, or circuits or their equivalents. Thus, the scope of the disclosure should not be limited by the specific examples described herein, but only by the claims and their equivalents.

Claims

1. An optical imaging system, comprising: a first lens having positive refractive power; a second lens having positive refractive power; a third lens having negative refractive power; a fourth lens having refractive power; a fifth lens having negative refractive power; a sixth lens having refractive power; a seventh lens having positive refractive power; and an eighth lens having negative refractive power, wherein the first lens to the eighth lens are sequentially arranged from an object side, wherein the optical imaging system has a total of 8 lenses, wherein D12 / D_MAX < 0.15, where D12 is a distance on an optical axis between an image side surface of the first lens and an object side surface of the second lens, and D_MAX is a maximum distance among distances between adjacent lenses, wherein (D12+D23) / D_SUM < 0.1, where D23 is a distance on an optical axis between an image side surface of the second lens and an object side surface of the third lens, and D_SUM is a sum of distances between each pair of adjacent lenses, and wherein 10.1180 ≤ |f4 / f| ≤ 71.7847, where f4 is a focal length of the fourth lens, and f is a total focal length of the optical imaging system. 0.9 < R2 / R3 < 1.1, where R2 is a radius of curvature of the image side surface of the first lens, and R3 is a radius of curvature of the object side surface of the second lens.

2. The optical imaging system of claim 1, wherein, The first lens has a meniscus shape convex toward the object side, and the second lens has a meniscus shape convex toward the object side.

3. The optical imaging system of claim 2, wherein, D12 / f < 0.

1.

4. The optical imaging system of claim 1, wherein, D67-D12-D23 > 0.2, where D67 is a distance on an optical axis between an image side surface of the sixth lens and an object side surface of the seventh lens.

5. The optical imaging system of claim 1, wherein, TTL / f < 1.2 and BFL / f < 0.3, where BFL is a distance on the optical axis from an image side surface of the eighth lens to the imaging surface.

6. The optical imaging system of claim 1, wherein, TTL / (2 IMG HT) < 0.8, where TTL is the distance on the optical axis from the object side surface of the first lens to the imaging surface, and IMG HT is half the diagonal length of the imaging surface.

7. The optical imaging system of claim 6, wherein, At least one of 25 < v1-v3 < 45, 25 < v1-v5 < 45, and 15 < v1-v6 < 25 is satisfied, where v1 is an Abbe number of the first lens, v3 is an Abbe number of the third lens, v5 is an Abbe number of the fifth lens, and v6 is an Abbe number of the sixth lens.

8. The optical imaging system of claim 1, wherein, The third lens, the fifth lens, and the sixth lens each have a refractive index of 1.57 or more.

9. The optical imaging system of claim 1, wherein, The third lens and the fifth lens each have a refractive index of more than 1.

64.

10. The optical imaging system of claim 9, wherein, |f1 / f2| < 1, where f1 is a focal length of the first lens, and f2 is a focal length of the second lens.

11. The optical imaging system of claim 1, wherein, 0 < f1 / f < 1.

4.

12. The optical imaging system of claim 11, wherein, 5 < f2 / f < 50.

13. The optical imaging system of claim 12, wherein, The first lens has a convex object side surface and a concave image side surface.

14. The optical imaging system of claim 1, wherein, The second lens has a convex object side surface and a concave image side surface.

15. The optical imaging system of claim 1, wherein, The third lens has a convex object side surface and a concave image side surface.

16. The optical imaging system of claim 1, wherein, The fourth lens has a concave object side surface and a convex image side surface.

17. The optical imaging system of claim 1, wherein, ​ 18. The optical imaging system of claim 1, wherein, The fifth lens has a convex object side surface in the paraxial region and a concave image side surface in the paraxial region.

19. The optical imaging system of claim 1, wherein, The sixth lens has a convex object side surface in the paraxial region and a concave image side surface in the paraxial region.

20. The optical imaging system of claim 1, wherein, The seventh lens has a convex object side surface in the paraxial region and a concave image side surface in the paraxial region, and the eighth lens has a convex object side surface in the paraxial region and a concave image side surface in the paraxial region.

Images