Optical imaging system

Abstract

An optical imaging system includes: 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 to eighth lenses are arranged sequentially from the object side, the optical imaging system has a total of 8 lenses, TTL / (2*IMG HT)<0.8, where TTL is the distance on the optical axis from the object side of the first lens to the imaging plane, and IMG HT is half the diagonal length of the imaging plane, and (D12+D23) / D_SUM<0.1, where D12 is the distance on the optical axis between the image side of the first lens and the object side of the second lens, and D23 is the distance on 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.

Description

[0001] Cross-references 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 satisfies 0.9 < R2 / R3 < 1.1, where R2 is the radius of curvature of the image-side surface of the first lens, and R3 is the radius of curvature of the object-side surface of the second lens.

[0013] The optical imaging system satisfies that 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.

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

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

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

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

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

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

[0020] The third lens and the fifth lens may each have a refractive index greater than 1.64.

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

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

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

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

[0025] In a general sense, 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 refractive power of the first and second lenses has a different sign than that of the third lens. At least three of the lenses from the third to the eighth lens each have a refractive index of 1.57 or greater, and satisfy (D12 + D23) / D_SUM < 0.1, 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, D23 is the distance along the optical axis between the image-side surface of the second lens and the object-side surface of the third lens, and D_SUM is the sum of the distances between each pair of adjacent lenses.

[0026] Other features and aspects will become apparent from the following detailed description, the accompanying drawings, and the appended claims. Attached Figure Description

[0027] Figure 1 It is a configuration diagram of the optical imaging system based on the first example.

[0028] Figure 2 It is shown Figure 1 The diagram shows the aberration characteristics of the optical imaging system.

[0029] Figure 3 It is a configuration diagram of the optical imaging system based on the second example.

[0030] Figure 4 It is shown Figure 3 The diagram shows the aberration characteristics of the optical imaging system.

[0031] Figure 5 It is a configuration diagram of the optical imaging system based on the third example.

[0032] Figure 6 It is shown Figure 5 The diagram shows the aberration characteristics of the optical imaging system.

[0033] Figure 7 It is a configuration diagram of the optical imaging system based on the fourth example.

[0034] Figure 8 It is shown Figure 7 The diagram shows the aberration characteristics of the optical imaging system.

[0035] Figure 9It is a configuration diagram of the optical imaging system based on the fifth example.

[0036] Figure 10 It is shown Figure 9 The diagram shows the aberration characteristics of the optical imaging system.

[0037] Throughout the accompanying drawings and detailed embodiments, the same reference numerals refer to the same elements. For purposes of clarity, illustration, and convenience, the drawings may not be drawn to scale, and the relative dimensions, scale, and depiction of elements in the drawings may be exaggerated. Detailed Implementation

[0038] The following detailed embodiments are provided to help the reader gain a full understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent to those skilled in the art. The order of operations described herein is merely illustrative, except for operations that must occur in a specific order, and is not limited to the order presented herein; changes that will be apparent to those skilled in the art are possible. Furthermore, for clarity and brevity, descriptions of functions and constructions familiar to those skilled in the art may be omitted.

[0039] The features described herein may be implemented in various forms and should not be construed as limited to the examples described herein. Rather, embodiments described herein have been provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0040] In this document, it should be noted that the use of the word "may" (e.g., what an implementation or example may include or implement) with respect to implementations or examples means that there exists at least one implementation or example that includes or implements such a feature, and that all implementations and examples are not limited thereto.

[0041] Throughout this specification, when an element such as a layer, region, or substrate is described as being "on," "connected to," or "attached to" another element, the element may be directly "on," directly "connected to," or directly "attached to" the other element, or there may be one or more other elements between the element and the other element. Conversely, when an element is described as being "directly on," "directly connected to," or "directly attached to" another element, there are no other elements between the element and the other element.

[0042] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more items.

[0043] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited by these terms. Rather, these terms are used only to distinguish one component, part, region, layer, or section from another. Therefore, without departing from the teachings of the examples described herein, the first component, first part, first region, first layer, or first section mentioned in the examples may also be referred to as a second component, second part, second region, second layer, or second section.

[0044] Spatial relative terms such as “above,” “above,” “below,” and “below” may be used herein for descriptive convenience to describe the relationship of one element relative to another, as shown in the accompanying drawings. In addition to covering the orientation depicted in the drawings, these spatial relative terms are intended to also cover different orientations of the device in use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “above” another element would be located “below” or “below” that other element. Thus, depending on the spatial orientation of the device, the term “above” covers both “above” and “below” orientations. The device may also be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0045] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the articles “a,” “an,” and “the” are intended to include plural forms as well. The terms “comprising,” “including,” and “having” indicate the presence of stated features, numbers, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, components, elements, and / or combinations thereof.

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

[0047] The features of the examples described herein can be combined in various ways, which will become apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have multiple configurations, other configurations will be apparent upon understanding the disclosure of this application.

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

[0049] In the following lens configuration diagrams, for the purpose of description, the thickness, size, and shape of the lens are slightly exaggerated, and the shapes of the spherical or aspherical surfaces suggested in the lens configuration diagrams are presented as examples, but are not limited thereto.

[0050] The optical imaging system described in the example includes at least eight lenses.

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

[0052] Furthermore, in each lens, the first surface (or object-side surface) refers to the surface closer to the object side, and the second surface (or image-side surface) refers to the surface closer to the image side. Additionally, in this specification, the values ​​for the lens's radius of curvature, thickness, distance, and focal length are all in mm, and the field of view (FOV) is in degrees.

[0053] Furthermore, in the description of the shape of each lens, a convex shape on a surface means that the paraxial region of that surface is convex, and a concave shape on a surface means that the paraxial region of that surface is concave. A flat surface means that the paraxial region of that surface is flat.

[0054] Therefore, even when one surface of the lens is described as convex, the edge portion of the lens can be concave. Similarly, even when one surface of the lens is described as concave, the edge portion of the lens can be convex. Furthermore, even when one surface of the lens is described as a flat surface, the edge portion of the lens can be either 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 described in the example includes at least eight lenses.

[0057] For example, the optical imaging system according to the 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 described in the example may include nine or more lenses as needed.

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

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

[0061] In addition, the optical imaging system may further include an aperture for adjusting the amount of light.

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

[0063] In addition, all the lenses have aspherical surfaces. For example, each of the first lens to the eighth lens may 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 may be aspherical. In this case, the aspherical surfaces of the first lens to the eighth lens are represented by Equation 1.

[0065] [Equation 1]

[0066]

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

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

[0069] The optical imaging system according to the example may 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 [Conditional Expression 5]

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

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

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

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

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

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

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

[0082] -2 < f1 / f |f1 / f3| < 0 [Conditional Expression 13]

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

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

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

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

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

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

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

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

[0091] 1.5 < Fno < 2 [Conditional Expression 22] <00002​​​v1 is the Abbe number of the first lens, v3 is the Abbe number of the third lens, and v5 is the Abbe number of the fifth lens.

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

[0095] 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, D23 is the 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 the 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 maximum distance between adjacent lenses, D_SUM is the sum of the distances between adjacent lenses, R2 is the radius of curvature of the image side of the first lens, and R3 is the radius of curvature of the object side of the second lens.

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

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

[0099] The first lens has positive refractive power. Furthermore, the first lens may have a meniscus shape that convexes towards the object. Specifically, the first surface of the first lens may be convex, and the second surface of the first lens may be concave.

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

[0101] The second lens has positive refractive power. Furthermore, the second lens may have a meniscus shape that convexes towards the object. Specifically, the first surface of the second lens may be convex, and the second surface of the second lens may have a concave shape.

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

[0103] The third lens has negative refractive power. Furthermore, the third lens may have a meniscus shape that convexes towards the object. Specifically, the first surface of the third lens may be convex, and the second surface of the third lens may 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 either positive or negative refractive power. Furthermore, the fourth lens may have a meniscus shape that convexes towards the image side. Specifically, the first surface of the fourth lens may be concave, and the second surface of the fourth lens may 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 negative refractive power. Furthermore, the fifth lens may have a meniscus shape that convexes towards the object. Specifically, the first surface of the fifth lens may be convex in the paraxial region, and the second surface of the fifth lens may 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 may 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the fifth lens may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0110] The sixth lens has either positive or negative refractive power. Furthermore, the sixth lens may have a meniscus shape that convexes towards the object. Specifically, the first surface of the sixth lens may be convex in the paraxial region, and the second surface of the sixth lens may 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 may 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the sixth lens may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0113] The seventh lens has positive refractive power. Furthermore, the seventh lens may have a meniscus shape that convexes towards the object. Specifically, the first surface of the seventh lens may be convex in the paraxial region, and the second surface of the seventh lens may be concave in the paraxial region.

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

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

[0116] The eighth lens has negative refractive power. Furthermore, the eighth lens may have a meniscus shape that convexes towards the object. Specifically, the first surface of the eighth lens may be convex in the paraxial region, and the second surface of the eighth lens may be concave in the paraxial region.

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

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

[0119] The first and second lenses may be formed of plastic materials with the same optical properties, and the second and third lenses may be formed of plastic materials with different optical properties.

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

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

[0124] The signs of the refractive power of the first and second lenses may differ from those of the refractive power of the third lens. For example, both the first and second lenses may have positive refractive power, and the third lens may have negative refractive power.

[0125] The image-side surface of the first lens and the object-side surface of the second lens may have a shape that protrudes in the same direction. For example, both the image-side surface of the first lens and the object-side surface of the second lens protrude toward the object.

[0126] The radius of curvature of the image-side surface of the first lens and the radius of curvature 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 radius of curvature of the image-side surface of the first lens to the radius of curvature of the object-side surface of the second lens can be between 0.9 and 1.1.

[0127] At least three lenses in the optical imaging system may have a refractive index of 1.57 or higher. At least three of the other lenses (excluding the first and second lenses, e.g., the third through eighth lenses) may have a refractive index of 1.57 or higher. For example, the third, fifth, and sixth lenses may have a refractive index of 1.57 or higher.

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

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

[0130] Reference Figure 1 and Figure 2 Describe the optical imaging system according to the first example.

[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 may also include an aperture, a filter 190, and an image sensor 191.

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

[0133] [Table 1]

[0134] Face 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 optical imaging system of the first example has a total focal length f of 6.3135 mm, an Fno of 1.78, an FOV of 78.5°, and an IMG HT of 5.264 mm.

[0136] In the first example, the first lens 110 has 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 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 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 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 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the fifth lens 150. For example, the first surface of the fifth lens 150 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the fifth lens 150 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0142] The sixth lens 160 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the sixth lens 160. For example, the first surface of the sixth lens 160 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the sixth lens 160 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0144] The seventh lens 170 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the seventh lens 170. For example, the first surface of the seventh lens 170 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the seventh lens 170 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0146] The eighth lens 180 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the eighth lens 180. For example, the first surface of the eighth lens 180 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the eighth lens 180 may be concave in the paraxial region and convex in the portion other than the paraxial region.

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

[0149] [Table 2]

[0150]

[0151]

[0152] Reference Figure 3 and Figure 4 Describe the optical imaging system according to the second example.

[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 may also include an aperture, a filter 290, and an image sensor 291.

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

[0155] [Table 3]

[0156]

[0157]

[0158] According to the second example, the total focal length f is 6.317 mm, Fno is 1.78, FOV is 78.4°, and IMG HT is 5.264 mm.

[0159] In the second example, the first lens 210 has 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 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 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 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 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the fifth lens 250. For example, the first surface of the fifth lens 250 may be convex in the paraxial region and concave in the portion other than the paraxial region. Similarly, the second surface of the fifth lens 250 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0165] The sixth lens 260 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the sixth lens 260. For example, the first surface of the sixth lens 260 may be convex in the paraxial region and concave in the portion other than the paraxial region. Similarly, the second surface of the sixth lens 260 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0167] The seventh lens 270 has 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] Furthermore, 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the seventh lens 270 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0169] The eighth lens 280 has 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] Furthermore, 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the eighth lens 280 may be concave in the paraxial region and convex in the portion other than the paraxial region.

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

[0172] [Table 4]

[0173]

[0174]

[0175]

[0176] Reference Figure 5 and Figure 6 Describe the optical imaging system according to the third example.

[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 may also include an aperture, a filter 390, and an image sensor 391.

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

[0179] [Table 5]

[0180]

[0181]

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

[0183] In the third example, the first lens 310 has 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 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 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 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 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the fifth lens 350. For example, the first surface of the fifth lens 350 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the fifth lens 350 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0189] The sixth lens 360 has 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] Furthermore, 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the sixth lens 360 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0191] The seventh lens 370 has 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] Furthermore, 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the seventh lens 370 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0193] The eighth lens 380 has 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] Furthermore, 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the eighth lens 380 may be concave in the paraxial region and convex in the portion other than the paraxial region.

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

[0196] [Table 6]

[0197]

[0198]

[0199] Reference Figure 7 and Figure 8 Describe the optical imaging system according to the fourth example.

[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 may also include an aperture, a filter 490, and an image sensor 491.

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

[0202] [Table 7]

[0203] Face 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] According to the fourth example, the optical imaging system has a total focal length f of 6.8256 mm, an Fno of 1.78, an FOV of 74.2°, and an IMG HT of 5.264 mm.

[0205] In the fourth example, the first lens 410 has 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 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 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 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 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] Furthermore, 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the fifth lens 450 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0211] The sixth lens 460 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the sixth lens 460. For example, the first surface of the sixth lens 460 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the sixth lens 460 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0213] The seventh lens 470 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the seventh lens 470. For example, the first surface of the seventh lens 470 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the seventh lens 470 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0215] The eighth lens 480 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the eighth lens 480. For example, the first surface of the eighth lens 480 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the eighth lens 480 may be concave in the paraxial region and convex in the portion other than the paraxial region.

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

[0218] [Table 8]

[0219]

[0220]

[0221] Reference Figure 9 and Figure 10Describe the optical imaging system according to the fifth example.

[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 may also include an aperture, a filter 590, and an image sensor 591.

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

[0224] [Table 9]

[0225]

[0226]

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

[0228] In the fifth example, the first lens 510 has 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 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 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 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 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] Furthermore, 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 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the fifth lens 550 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0234] The sixth lens 560 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the sixth lens 560. For example, the first surface of the sixth lens 560 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the sixth lens 560 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0236] The seventh lens 570 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the seventh lens 570. For example, the first surface of the seventh lens 570 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the seventh lens 570 may be concave in the paraxial region and convex in the portion other than the paraxial region.

[0238] The eighth lens 580 has 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] Furthermore, at least one inflection point is formed on at least one of the first and second surfaces of the eighth lens 580. For example, the first surface of the eighth lens 580 may be convex in the paraxial region and concave in the portion other than the paraxial region. The second surface of the eighth lens 580 may be concave in the paraxial region and convex in the portion other than the paraxial region.

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

[0241] [Table 10]

[0242]

[0243]

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

[0245] [Table 11]

[0246]

[0247]

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

[0249] While this disclosure includes specific examples, it will be apparent upon understanding the disclosure of this application 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 herein should be interpreted in a descriptive sense only and not for limiting purposes. The description of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Suitable results may also be obtained if the described techniques are performed in a different order, and / or if components in the described system, architecture, apparatus, or circuit are combined in different ways and / or replaced or supplemented with other components or their equivalents. Therefore, the scope of this 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 this disclosure.

Claims

1. An optical imaging system, comprising: The first lens has positive refractive power; The second lens has positive refractive power; The third lens has negative refractive power; The fourth lens has refractive power; The fifth lens has negative refractive power; The sixth lens has refractive power; The seventh lens has positive refractive power; as well as The eighth lens has negative refractive power. The first lens to the eighth lens are arranged sequentially from the object side. The optical imaging system has a total of 8 lenses. Wherein, TTL / (2 IMG HT) < 0.8, where TTL is the distance along the optical axis from the object side of the first lens to the imaging plane, and IMG HT is half the diagonal length of the imaging plane. Where (D12+D23) / D_SUM < 0.1, where D12 is the distance on the optical axis between the image-side surface of the first lens and the object-side surface of the second lens, and D23 is the distance on the optical axis between the image-side surface of the second lens and the object-side surface of the third lens, and D_SUM is the sum of the distances between each pair of adjacent lenses. Where 5 < f2 / f < 50, f2 is the focal length of the second lens, and f is the total focal length of the optical imaging system.

2. The optical imaging system according to claim 1, wherein, 0.9 < R2 / R3 < 1.1, where R2 is the radius of curvature of the image-side surface of the first lens, and R3 is the radius of curvature of the object-side surface of the second lens.

3. The optical imaging system according to claim 2, wherein, The first lens has a meniscus shape that bulges toward the object side, and the second lens has a meniscus shape that bulges toward the object side.

4. The optical imaging system according to claim 1, wherein, D12 / D_MAX < 0.15, where D_MAX is the maximum distance between adjacent lenses.

5. The optical imaging system according to claim 4, wherein, D12 / f < 0.

1.

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

7. The optical imaging system according to claim 6, wherein, TTL / f < 1.2 and BFL / f < 0.3, where BFL is the distance from the image-side surface of the eighth lens to the imaging surface along the optical axis.

8. The optical imaging system according to claim 1, wherein, It satisfies at least one of 25 < v1-v3 < 45, 25 < v1-v5 < 45, and 15 < v1-v6 < 25, where v1 is the Abbe number of the first lens, v3 is the Abbe number of the third lens, v5 is the Abbe number of the fifth lens, and v6 is the Abbe number of the sixth lens.

9. The optical imaging system according to claim 1, wherein, The third lens, the fifth lens, and the sixth lens each have a refractive index of 1.57 or greater.

10. The optical imaging system according to claim 9, wherein, The third lens and the fifth lens each have a refractive index greater than 1.

64.

11. The optical imaging system according to claim 1, wherein, |f1 / f2| < 1, where f1 is the focal length of the first lens.

12. The optical imaging system according to claim 11, wherein, 0 < f1 / f < 1.

4.

13. The optical imaging system according to claim 1, wherein, The first lens has a convex object-side surface and a concave image-side surface.

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

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

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

17. The optical imaging system according to claim 1, wherein, The fifth lens has an object-side surface that bulges in the paraxial region and an image-side surface that is recessed in the paraxial region.

18. The optical imaging system according to claim 1, wherein, The sixth lens has an object-side surface that bulges in the paraxial region and an image-side surface that is recessed in the paraxial region.

19. The optical imaging system according to claim 1, wherein, The seventh lens has an object-side surface that bulges in the paraxial region and an image-side surface that is recessed in the paraxial region, and the eighth lens has an object-side surface that bulges in the paraxial region and an image-side surface that is recessed in the paraxial region.

Images