Optical image capturing system

Abstract

An optical imaging system is provided. The optical image capturing system includes a first lens having a positive refractive power, a second lens having a negative refractive power, a third lens having a refractive index greater than 1.66, a fourth lens having a positive refractive power, a sixth lens having a negative refractive power, a seventh lens having a refractive index greater than 1.66, and an eighth lens disposed in order from an object side toward an image plane. And wherein the optical imaging system satisfies the following conditional expression: TTL / (2 * IMG HT) lt; 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.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0171739 filed on November 30, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety for all purposes. Technical Field

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

[0004] The portable terminal is equipped with a camera including an optical imaging system composed of a plurality of lenses to enable video calling and image capturing.

[0005] Furthermore, as functions implemented by cameras in portable terminals gradually increase, demands for cameras for portable terminals having high resolution are also growing.

[0006] Recently, in order to achieve clearer image quality, image sensors with high pixels (eg, 13 million to 100 million pixels) are implemented in cameras for portable terminals.

[0007] In other words, the size of image sensors has increased, and as a result, the overall track length of optical imaging systems has also increased, which may eventually cause the camera to protrude from the portable terminal.

[0008] As portable terminals continue to become smaller, it is beneficial if cameras for portable terminals have a slim form factor. Therefore, it is desirable to develop optical imaging systems that are both slim and capable of achieving high resolution. Utility Model Content

[0009] This Summary is provided to introduce a selection of concepts in a concise form, and these concepts will be further described in the Detailed Description below. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[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 in sequence from the object side toward the imaging surface. The first lens has a positive refractive power, and the second lens has a negative refractive power. The second lens and the third lens each have a refractive index greater than 1.66, and the optical imaging system satisfies the following conditional expression: TTL / (2×IMG HT)<0.64, 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 of the diagonal length of the imaging surface.

[0011] Each of at least three lenses including the second lens and the third lens among the first lens to the eighth lens may have a refractive index greater than 1.66, and the absolute value of the focal length of the second lens among the at least three lenses having a refractive index greater than 1.66 is the smallest absolute value.

[0012] The fifth lens may have a refractive index greater than 1.66, and the optical imaging system satisfies the following conditional expression: |v1-(v2+v3+v5)|<10, where v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, v3 is the Abbe number of the third lens, and v5 is the Abbe number of the fifth lens.

[0013] The following conditional expressions may be satisfied: 25<v1-v2<45 and 25<v1-v3<45, where v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, and v3 is the Abbe number of the third lens.

[0014] The following conditional expression may be satisfied: 15<v1-(v2+v3)<25, where v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, and v3 is the Abbe number of the third lens.

[0015] The following conditional expression may be satisfied: 1.3<Fno<1.6, where Fno is the F-number of the optical imaging system.

[0016] The following conditional expression may be satisfied: 0.9<f1 / f<1.2, where f1 is the focal length of the first lens, and f is the total focal length of the optical imaging system.

[0017] The following conditional expression may be satisfied: -3<f2 / f<-1, where f2 is the focal length of the second lens, and f is the total focal length of the optical imaging system.

[0018] The following conditional expression may be satisfied: |f3 / f|>30, where f3 is the focal length of the third lens, and f is the total focal length of the optical imaging system.

[0019] It can satisfy the following conditional expression: 0.3 < |f1 / f2| < 0.6, where f1 is the focal length of the first lens and f2 is the focal length of the second lens.

[0020] It can satisfy the following conditional expression: |f1 / f3| < 0.05, where f1 is the focal length of the first lens and f3 is the focal length of the third lens.

[0021] It can satisfy the following conditional expression: |f2 / f3| < 0.08, where f2 is the focal length of the second lens and f3 is the focal length of the third lens. [[ID=⑧]]

[0022] It can satisfy the following conditional expression: 1.3 < f12 / f < 1.7, where f12 is the combined focal length of the first lens and the second lens, and f is the total focal length of the optical imaging system.

[0023] It can satisfy the following conditional expression: 1.3 < f123 / f < 1.7, where f123 is the combined focal length from the first lens to the third lens.

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

[0025] The sixth lens can have a positive refractive power, the seventh lens can have a positive refractive power, and the eighth lens can have a negative refractive power.

[0026] According to the accompanying drawings and the following detailed description, other features and aspects will be apparent. Description of the Drawings

[0027] Figure 1 A configuration diagram of an exemplary optical imaging system according to a first exemplary embodiment is shown.

[0028] Figure 2 Shows Figure 1 The aberration characteristics of the exemplary optical imaging system shown in

[0029] Figure 3 A configuration diagram of an exemplary optical imaging system according to a second exemplary embodiment is shown.

[0030] Figure 4 Shows Figure 3 The aberration characteristics of the exemplary optical imaging system shown in

[0031] Figure 5 A configuration diagram of an exemplary optical imaging system according to a third exemplary embodiment is shown.

[0032] Figure 6 Shows Figure 5 The aberration characteristics of the exemplary optical imaging system shown in

[0033] Throughout the drawings and detailed description, unless otherwise described or specified, it is understood that the same reference numerals may refer to the same or similar elements, features and structures. For the purposes of clarity, illustration and convenience, the drawings may not be drawn to scale, and the relative sizes, proportions and descriptions of the elements in the drawings may be exaggerated. DETAILED DESCRIPTION

[0034] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the method, device and / or system described herein. However, various changes, modifications and equivalents of the method, device and / or system described herein will be apparent after understanding the disclosure of the application. For example, the order in the operation described herein and / or the order of the operation described herein are merely examples, and except for the order and / or the order of operations in the operation that must occur in a specific sequence, are not limited to the order set forth in this article, but can be changed, which will be apparent after understanding the disclosure of the application. As another example, except for the order and / or the order of operations in the operation that must occur in a sequence (for example, a specific sequence), the order in the order of operations and / or operations can be performed in parallel. In addition, for greater clarity and brevity, the description of features known after understanding the disclosure of the application can be omitted.

[0035] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. More specifically, the examples described herein are provided merely to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of this application. In this article, the use of the wording "may" (e.g., with respect to what an example or embodiment may include or implement) relative to an example or embodiment means that there is at least one example or embodiment that includes or implements such a feature, and all examples or embodiments are not limited thereto. The phrases "example" or "implementation" used herein have the same meaning, for example, the phrase "in one example" has the same meaning as "in one embodiment", and "in one or more examples" has the same meaning as "in one or more embodiments".

[0036] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the wording "one", "an" and "the" are intended to also include plural forms. As used herein, the wording "and / or" includes any one of the associated listed items and any combination of any two or more items. As non-limiting examples, the wording "comprises", "includes" and "has" illustrate the presence of the described features, quantity, operation, member, element and / or its combination, but does not exclude the existence or addition of one or more other features, quantity, operation, member, element and / or its combination, or the existence of alternative features, quantity, operation, member, element and / or its combination. In addition, although an embodiment can set forth the wording "comprises", "includes" and "has" to illustrate the existence of the described features, quantity, operation, member, element and / or its combination, other embodiments may exist, and in these other embodiments, there is not one or more of the described features, quantity, operation, member, element and / or its combination.

[0037] Throughout this specification, when a component, element, or layer is described as being "on another component, element, or layer," "connected to," "coupled to," or "engaged to" another component, element, or layer, it may be directly "on another component, element, or layer," "connected to," "coupled to," or "engaged to" the other component, element, or layer (e.g., in contact with the other component, element, or layer), or one or more other components, elements, or layers may reasonably be present between the component, element, or layer and the other component, element, or layer. When a component, element, or layer is described as being "directly on another component, element, or layer," "directly connected to," "directly coupled to," or "directly engaged to" another component, element, or layer, there are no other components, elements, or layers between the component, element, or layer and the other component, element, or layer. Similarly, expressions such as "between" and "directly between," as well as "adjacent" and "directly adjacent," may also be interpreted as described above.

[0038] Although terms such as "first," "second," and "third," or A, B, (a), (b), etc., may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Each of these terms is not intended to define, for example, the importance, sequence, or order of the corresponding member, component, region, layer, or portion, but is merely intended to distinguish the corresponding member, component, region, layer, or portion from other members, components, regions, layers, or portions. Thus, without departing from the teachings of the examples described herein, a first member, first component, first region, first layer, or first portion mentioned in these examples may also be referred to as a second member, second component, second region, second layer, or second portion.

[0039] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items. The phrases "at least one of A, B, and C," etc. are intended to have a disjunctive meaning, and these phrases "at least one of A, B, and C," etc. also include examples in which one or more of A, B, and C can be present (e.g., any combination of one or more of A, B, and C), unless the corresponding description and implementation require that the enumeration (e.g., "at least one of A, B, and C") be interpreted as having a conjunctive meaning.

[0040] One or more examples may provide an optical imaging system capable of achieving high resolution and having a small overall length.

[0041] In one or more exemplary embodiments of the following lens configurations, the thickness, size, and shape of the lenses are slightly exaggerated for illustrative purposes. In particular, the spherical or aspherical shapes shown in the lens configuration diagrams are illustrative but not limiting.

[0042] The first lens refers to a lens closest to the object side, and the eighth lens refers to a lens closest to the imaging plane (or image sensor).

[0043] Additionally, in one or more examples, the units of values ​​for the radius of curvature, thickness, distance, focal length, etc. of the lens are all in millimeters (mm), and the units of field of view (FOV) are in degrees.

[0044] In the description of each lens shape, a convex surface shape means that the paraxial region of the surface is convex, and a concave surface shape means that the paraxial region of the surface is concave. Therefore, even if a lens surface is described as having a convex shape, the edge portion of the lens may be concave. Similarly, even if a lens surface is described as having a concave shape, the edge portion of the lens may be convex.

[0045] The paraxial region is a very narrow region close to the optical axis.

[0046] The imaging plane may refer to a virtual plane on which a focus is formed by an optical imaging system. Alternatively, the imaging plane may refer to one surface of an image sensor that receives light.

[0047] An optical imaging system according to one or more exemplary embodiments may include eight lenses.

[0048] In an example, an optical imaging system according to an embodiment may include 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 toward the imaging surface. The first to eighth lenses are spaced apart from each other by a predetermined distance along the optical axis.

[0049] The optical imaging system according to one or more embodiments may include more than just eight lenses and may also include other components as needed.

[0050] In an example, the exemplary optical imaging system may further include an image sensor that converts an incident image of the object into an electrical signal.

[0051] In addition, the exemplary optical imaging system may further include an infrared filter (hereinafter referred to as a “filter”) that blocks infrared rays. The filter may be disposed between the eighth lens and the image sensor.

[0052] Additionally, the exemplary optical imaging system may further include a stop for controlling the amount of light.

[0053] The first to eighth lenses constituting the exemplary optical imaging system according to one or more exemplary embodiments may be formed of a plastic material.

[0054] In addition, at least one lens among the first to eighth lenses may have an aspherical surface. In addition, each of the first to eighth lenses may have at least one aspherical surface.

[0055] In an example, at least one of the object-side surface and the image-side surface of the first to eighth lenses may be aspherical. In this example, the aspherical surface of the first to eighth lenses is expressed by the following equation 1:

[0056] Equation 1:

[0057]

[0058] In Equation 1, c is the curvature of the lens (the inverse of the radius of curvature), K is the conic constant, and Y represents the distance from a specific point on the aspherical surface of the lens to the optical axis. Furthermore, constants A through H, J, and L through P refer to aspherical coefficients. Z(SAG) represents the distance along the optical axis between a specific point on the aspherical surface of the lens and the vertex of the aspherical surface.

[0059] The optical imaging system according to one or more exemplary embodiments may satisfy at least one of the following conditional expressions.

[0060] According to an embodiment, the optical imaging system can satisfy the conditional expression TTL / (2×IMG HT) < 0.64. In this example, TTL is the distance from the object side surface of the first lens to the imaging surface on the optical axis, and IMG HT is half of the diagonal length of the imaging surface. Accordingly, the optical imaging system can be miniaturized.

[0061] According to an embodiment, the optical imaging system can satisfy the conditional expression 1.3 < Fno < 1.6. In this example, Fno is the F-number of the optical imaging system. Accordingly, the image brightness and resolution can be improved.

[0062] According to an embodiment, the optical imaging system can satisfy the conditional expression 25 < v1 - v2 < 45. In this example, v1 is the Abbe number of the first lens, and v2 is the Abbe number of the second lens.

[0063] According to an embodiment, the optical imaging system can satisfy the conditional expression 25 < v1 - v3 < 45. In this example, v3 is the Abbe number of the third lens.

[0064] According to an embodiment, the optical imaging system can satisfy the conditional expression 15 < v1 - (v2 + v3) < 25.

[0065] According to an embodiment, the optical imaging system can satisfy the conditional expression |v1 - (v2 + v3 + v5)| < 10. In this example, v5 is the Abbe number of the fifth lens.

[0066] According to an embodiment, the optical imaging system can satisfy the conditional expression 0.9 < f1 / f < 1.2. In this example, f1 is the focal length of the first lens, and f is the total focal length of the optical imaging system.

[0067] According to an embodiment, the optical imaging system can satisfy the conditional expression -3 < f2 / f < -1. In this example, f2 is the focal length of the second lens.

[0068] According to an embodiment, the optical imaging system can satisfy the conditional expression |f3 / f| > 30. In this example, f3 is the focal length of the third lens.

[0069] According to an embodiment, the optical imaging system can satisfy the conditional expression 2.5 < f4 / f < 5. In this example, f4 is the focal length of the fourth lens.

[0070] According to an embodiment, the optical imaging system can satisfy the conditional expression -10 < f5 / f < -4. In this example, f5 is the focal length of the fifth lens.

[0071] According to an embodiment, the optical imaging system can satisfy the conditional expression 0.3 < |f1 / f2| < 0.6.

[0072] According to an embodiment, the optical imaging system may satisfy the conditional expression |f1 / f3| < 0.05.

[0073] According to an embodiment, the optical imaging system may satisfy the conditional expression |f2 / f3| < 0.08.

[0074] According to an embodiment, the optical imaging system may satisfy the conditional expression 1.3 < f12 / f < 1.7. In this example, f12 is the combined focal length of the first lens and the second lens.

[0075] According to an embodiment, the optical imaging system may satisfy the conditional expression 1.3 < f123 / f < 1.7. In this example, f123 is the combined focal length of the first lens, the second lens, and the third lens.

[0076] The first lens to the eighth lens constituting an exemplary optical imaging system according to one or more embodiments will be described.

[0077] The first lens may have a positive refractive power. In addition, the first lens may have a meniscus shape convex toward the object side. Additionally, the object side surface of the first lens may be convex, and the image side surface of the first lens may be concave.

[0078] At least one of the object side surface and the image side surface of the first lens may be aspherical. In the example, both the object side surface and the image side surface of the first lens may be aspherical.

[0079] The second lens may have a negative refractive power. In addition, the second lens may have a meniscus shape convex toward the object side. Additionally, the object side surface of the second lens may be convex, and the image side surface of the second lens may be concave.

[0080] At least one of the object side surface and the image side surface of the second lens may be aspherical. In the example, both the object side surface and the image side surface of the second lens may be aspherical.

[0081] The third lens may have a positive or negative refractive power. In addition, the third lens may have a meniscus shape convex toward the object side. In addition, the object side surface of the third lens may be convex, and the image side surface of the third lens may be concave.

[0082] At least one of the object side surface and the image side surface of the third lens may be aspherical. In the example, both the object side surface and the image side surface of the third lens may be aspherical.

[0083] The fourth lens may have a positive refractive power. In addition, the fourth lens may have a meniscus shape convex toward the image side. Additionally, the object side surface of the fourth lens may be concave, and the image side surface of the fourth lens may be convex.

[0084] At least one of the object-side surface and the image-side surface of the fourth lens may be aspherical. For example, both the object-side surface and the image-side surface of the fourth lens may be aspherical.

[0085] The fifth lens element may have negative refractive power. In addition, the fifth lens element may have a meniscus shape that is convex toward the image side. The object side surface of the fifth lens element may be concave, and the image side surface of the fifth lens element may be convex.

[0086] At least one of the object-side surface and the image-side surface of the fifth lens may be aspherical. For example, both the object-side surface and the image-side surface of the fifth lens may be aspherical.

[0087] The sixth lens element may have positive refractive power. In addition, the sixth lens element may have a meniscus shape that is convex toward the object side. In addition, the object-side surface of the sixth lens element may be convex, and the image-side surface of the sixth lens element may be concave.

[0088] At least one of the object-side surface and the image-side surface of the sixth lens may be aspherical. For example, both the object-side surface and the image-side surface of the sixth lens may be aspherical.

[0089] The sixth lens element may have at least one inflection point formed on at least one of its object-side surface and image-side surface. For example, the object-side surface of the sixth lens element may be convex in the paraxial region and concave in the rest of the region. The image-side surface of the sixth lens element may be concave in the paraxial region and convex in the rest of the region.

[0090] The seventh lens element may have positive refractive power. In addition, the seventh lens element may have a shape in which both surfaces are convex. In addition, the object-side surface and the image-side surface of the seventh lens element may be convex.

[0091] At least one of the object-side surface and the image-side surface of the seventh lens may be aspherical. In an example, both the object-side surface and the image-side surface of the seventh lens may be aspherical.

[0092] The seventh lens element may also have at least one inflection point formed on at least one of its object-side surface and image-side surface. For example, the object-side surface of the seventh lens element may be convex in the paraxial region and concave in the rest of the region. The image-side surface of the seventh lens element may be convex in the paraxial region and concave in the rest of the region.

[0093] The eighth lens element may have negative refractive power. In addition, the eighth lens element may have a shape in which both surfaces are concave. In addition, the object-side surface and the image-side surface of the eighth lens element may be concave.

[0094] At least one of the object-side surface and the image-side surface of the eighth lens may be aspherical. For example, both the object-side surface and the image-side surface of the eighth lens may be aspherical.

[0095] The eighth lens element may also have at least one inflection point formed on at least one of its object-side surface and image-side surface. In some examples, the object-side surface of the eighth lens element may be concave in the paraxial region and convex in the rest of the region. The image-side surface of the eighth lens element may be concave in the paraxial region and convex in the rest of the region.

[0096] The second lens and the third lens may each be configured to have a refractive index greater than that of the first lens.

[0097] In an embodiment, the second lens and the third lens may each have a refractive index greater than 1.66.

[0098] Among the first to eighth lenses, at least three lenses including the second lens and the third lens may have a refractive index greater than 1.66. In an example, the second lens, the third lens, and the fifth lens may each have a refractive index greater than 1.66.

[0099] In an embodiment, the refractive index of the fifth lens may be greater than the refractive index of the second lens and the refractive index of the third lens, respectively. In an example, the fifth lens may have a refractive index greater than 1.68.

[0100] In an exemplary optical imaging system, among lenses having a refractive index greater than 1.66, at least two lenses may be configured to have negative refractive power.

[0101] In the exemplary optical imaging system, an absolute value of a focal length of the second lens may be the smallest among lenses having a refractive index greater than 1.66.

[0102] The Abbe number of the third lens may be less than 50, the Abbe number of the fourth lens may be greater than 50, and the Abbe number of the fifth lens may be less than 50.

[0103] In addition, the Abbe number of the seventh lens and the Abbe number of the eighth lens may each be greater than 50.

[0104] Will refer to Figure 1 and Figure 2 An exemplary optical imaging system according to a first embodiment is described.

[0105] The exemplary optical imaging system 100 according to the first embodiment may include 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 further include a filter 190 and an image sensor.

[0106] The optical imaging system according to the first embodiment can form a focus (or a focused image) on an imaging surface 191. The imaging surface 191 may refer to a surface on which the optical imaging system forms a focus. As an example, the imaging surface 191 may refer to a surface of an image sensor that receives light.

[0107] Lens characteristics (curvature radius, thickness of the lens or distance between lenses, refractive index, Abbe number, and effective radius) of each lens are shown in Table 1 below.

[0108] Table 1

[0109] Face number part Radius of curvature Thickness or distance Refractive index Abbe number Effective radius S1 First lens 2.833 1.022 1.5463 55.99 2.060 S2 13.581 0.030 1.955 S3 Second lens 6.308 0.230 1.6789 19.24 1.853 S4 3.804 0.518 1.671 S5 The third lens 24.920 0.282 1.6789 19.24 1.660 S6 26.058 0.242 1.660 S7 Fourth lens -224.294 0.633 1.5463 55.99 1.730 S8 -11.048 0.143 1.932 S9 Fifth lens -10.328 0.239 1.6892 18.15 2.154 S10 -14.338 0.362 2.228 S11 Sixth lens 3.999 0.366 1.5707 37.40 2.843 S12 4.482 0.647 3.267 S13 Seventh lens 6.378 0.640 1.5371 55.74 3.463 S14 -9.640 0.988 3.877 S15 Eighth lens -10.942 0.353 1.5371 55.74 4.357 S16 3.067 0.200 4.729 S17 filter infinity 0.210 5.724 S18 infinity 0.662 5.814 S19 Imaging surface infinity 6.335

[0110] In the first embodiment, the first lens 110 may have positive refractive power, the object-side surface of the first lens 110 may be convex, and the image-side surface of the first lens 110 may be concave.

[0111] The second lens 120 may have negative refractive power, the object-side surface of the second lens 120 may be convex, and the image-side surface of the second lens 120 may be concave.

[0112] The third lens 130 may have positive refractive power, an object-side surface of the third lens 130 may be convex, and an image-side surface of the third lens 130 may be concave.

[0113] The fourth lens 140 may have positive refractive power, an object-side surface of the fourth lens 140 may be concave, and an image-side surface of the fourth lens 140 may be convex.

[0114] The fifth lens 150 may have negative refractive power, the object-side surface of the fifth lens 150 may be concave, and the image-side surface of the fifth lens 150 may be convex.

[0115] The sixth lens 160 may have positive refractive power, an object-side surface of the sixth lens 160 may be convex, and an image-side surface of the sixth lens 160 may be concave.

[0116] Furthermore, the sixth lens element 160 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. In some examples, the object-side surface of the sixth lens element 160 may be convex in the paraxial region and concave in the region outside the paraxial region. Furthermore, the image-side surface of the sixth lens element 160 may be concave in the paraxial region and convex in the region outside the paraxial region.

[0117] The seventh lens 170 may have positive refractive power, and the object-side and image-side surfaces of the seventh lens 170 may be convex in a paraxial region.

[0118] Furthermore, the seventh lens element 170 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. For example, the object-side surface of the seventh lens element 170 may be convex in the paraxial region and concave in the region outside the paraxial region. Furthermore, the image-side surface of the seventh lens element 170 may be convex in the paraxial region and concave in the region outside the paraxial region.

[0119] The eighth lens 180 may have negative refractive power, and the object-side and image-side surfaces of the eighth lens 180 may be concave in a paraxial region.

[0120] Furthermore, the eighth lens element 180 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. In some examples, the object-side surface of the eighth lens element 180 may be concave in the paraxial region and convex in portions other than the paraxial region. Furthermore, the image-side surface of the eighth lens element 180 may be concave in the paraxial region and convex in portions other than the paraxial region.

[0121] Each surface of the first to eighth lenses 110 to 180 may have an aspheric coefficient as shown in the following Table 2. In an example, both the object-side surface and the image-side surface of the first to eighth lenses 110 to 180 may be aspheric.

[0122] Table 2

[0123]

[0124]

[0125]

[0126] Furthermore, the exemplary optical imaging system configured as described above may have the following features: Figure 2 Aberration characteristics shown in .

[0127] Will refer to Figure 3 and Figure 4 An exemplary optical imaging system according to the second embodiment is described.

[0128] An exemplary optical imaging system 200 according to the second embodiment may include 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 further include a filter 290 and an image sensor.

[0129] The exemplary optical imaging system according to the second embodiment can form a focus (or a focused image) on an imaging surface 291. The imaging surface 291 may refer to a surface on which a focus is formed by the optical imaging system. In an example, the imaging surface 291 may refer to a surface of an image sensor that receives light.

[0130] The lens characteristics of each lens (curvature radius, thickness of the lens or distance between lenses, refractive index, Abbe number, and effective radius) are shown in Table 3 below.

[0131] Table 3

[0132]

[0133]

[0134] In the second embodiment, the first lens 210 may have positive refractive power, the object-side surface of the first lens 210 may be convex, and the image-side surface of the first lens 210 may be concave.

[0135] The second lens 220 may have negative refractive power, the object-side surface of the second lens 220 may be convex, and the image-side surface of the second lens 220 may be concave.

[0136] The third lens 230 may have negative refractive power, the object-side surface of the third lens 230 may be convex, and the image-side surface of the third lens 230 may be concave.

[0137] The fourth lens 240 may have positive refractive power, an object-side surface of the fourth lens 240 may be concave, and an image-side surface of the fourth lens 240 may be convex.

[0138] The fifth lens 250 may have negative refractive power, the object-side surface of the fifth lens 250 may be concave, and the image-side surface of the fifth lens 250 may be convex.

[0139] The sixth lens 260 may have positive refractive power, an object-side surface of the sixth lens 260 may be convex, and an image-side surface of the sixth lens 260 may be concave.

[0140] Furthermore, the sixth lens element 260 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. In an example, the object-side surface of the sixth lens element 260 may be convex in the paraxial region and concave in the region outside the paraxial region. Furthermore, the image-side surface of the sixth lens element 260 may be concave in the paraxial region and convex in the region outside the paraxial region.

[0141] The seventh lens 270 may have positive refractive power, and the object-side and image-side surfaces of the seventh lens 270 may be convex in a paraxial region.

[0142] Furthermore, the seventh lens element 270 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. In some examples, the object-side surface of the seventh lens element 270 may be convex in the paraxial region and concave in portions other than the paraxial region. The image-side surface of the seventh lens element 270 may be convex in the paraxial region and concave in portions other than the paraxial region.

[0143] The eighth lens 280 may have negative refractive power, and the object-side surface and the image-side surface of the eighth lens 280 may be concave in a paraxial region.

[0144] Furthermore, the eighth lens 280 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. In an example, the object-side surface of the eighth lens 280 may be concave in the paraxial region and convex in portions other than the paraxial region. The image-side surface of the eighth lens 280 may be concave in the paraxial region and convex in portions other than the paraxial region.

[0145] Each surface of the first to eighth lenses 210 to 280 may have an aspheric coefficient as shown in the following Table 4. In an example, both the object-side surface and the image-side surface of the first to eighth lenses 210 to 280 may be aspheric.

[0146] Table 4

[0147]

[0148]

[0149]

[0150] Furthermore, the exemplary optical imaging system configured as described above may have the following features: Figure 4 Aberration characteristics shown in .

[0151] Will refer to Figure 5 and Figure 6 An exemplary optical imaging system according to a third embodiment is described.

[0152] An exemplary optical imaging system 300 according to the third embodiment may include 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 further include a filter 390 and an image sensor.

[0153] The optical imaging system according to the third embodiment can form a focus (or a focused image) on an imaging surface 391. The imaging surface 391 may refer to a surface on which the optical imaging system forms a focus. In an example, the imaging surface 391 may refer to a surface of an image sensor that receives light.

[0154] The lens characteristics of each lens (curvature radius, thickness of the lens or distance between lenses, refractive index, Abbe number, and effective radius) are shown in Table 5 below.

[0155] Table 5

[0156]

[0157]

[0158] In the third embodiment, the first lens 310 may have positive refractive power, the object-side surface of the first lens 310 may be convex, and the image-side surface of the first lens 310 may be concave.

[0159] The second lens 320 may have negative refractive power, the object-side surface of the second lens 320 may be convex, and the image-side surface of the second lens 320 may be concave.

[0160] The third lens 330 may have negative refractive power, an object-side surface of the third lens 330 may be convex, and an image-side surface of the third lens 330 may be concave.

[0161] The fourth lens 340 may have positive refractive power, an object-side surface of the fourth lens 340 may be concave, and an image-side surface of the fourth lens 340 may be convex.

[0162] The fifth lens 350 may have negative refractive power, the object-side surface of the fifth lens 350 may be concave, and the image-side surface of the fifth lens 350 may be convex.

[0163] The sixth lens 360 may have positive refractive power, an object-side surface of the sixth lens 360 may be convex, and an image-side surface of the sixth lens 360 may be concave.

[0164] Furthermore, the sixth lens element 360 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. For example, the object-side surface of the sixth lens element 360 may be convex in the paraxial region and concave in the region outside the paraxial region. The image-side surface of the sixth lens element 360 may be concave in the paraxial region and convex in the region outside the paraxial region.

[0165] The seventh lens 370 may have positive refractive power, and the object-side and image-side surfaces of the seventh lens 370 may be convex in a paraxial region.

[0166] Furthermore, the seventh lens element 370 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. In some examples, the object-side surface of the seventh lens element 370 may be convex in the paraxial region and concave in portions other than the paraxial region. The image-side surface of the seventh lens element 370 may be convex in the paraxial region and concave in portions other than the paraxial region.

[0167] The eighth lens 380 may have negative refractive power, and the object-side surface and the image-side surface of the eighth lens 380 may be concave.

[0168] Furthermore, the eighth lens element 380 may have at least one inflection point formed on at least one of its object-side surface and image-side surface. In some examples, the object-side surface of the eighth lens element 380 may be concave in the paraxial region and convex in portions other than the paraxial region. The image-side surface of the eighth lens element 380 may be concave in the paraxial region and convex in portions other than the paraxial region.

[0169] Each surface of the first to eighth lenses 310 to 380 may have an aspheric coefficient as shown in the following Table 6. In an example, both the object-side surface and the image-side surface of the first to eighth lenses 310 to 380 may be aspheric.

[0170] Table 6

[0171]

[0172]

[0173]

[0174] Furthermore, the exemplary optical imaging system configured as described above may have the following features: Figure 6 Aberration characteristics shown in .

[0175] Table 7

[0176] First embodiment Second embodiment Third embodiment Fno 1.522 1.535 1.561 TTL 7.767 7.808 7.880 IMG HT 6.329 6.329 6.329 FOV 89.12 88.25 87.358 f 6.114 6.262 6.357 f1 6.340 6.344 6.346 f2 -14.666 -15.917 -16.231 f3 763.536 -293.262 -336.893 f4 21.246 19.984 20.554 f5 -54.932 -33.597 -31.945 f6 51.018 40.583 40.389 f7 7.247 7.297 7.358 f8 -4.421 -4.300 -4.213 f12 9.766 9.356 9.271 f123 9.628 9.564 9.447

[0177] In Table 7, Fno is the F number of the exemplary optical imaging system, TTL is the distance from the object side surface of the first lens to the imaging plane on the optical axis, IMG HT is half the diagonal length of the imaging plane, and FOV is the field of view of the optical imaging system.

[0178] 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, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

[0179] In an exemplary optical imaging system according to one or more embodiments, it is possible to reduce the size while achieving high resolution.

[0180] Although the present disclosure includes specific examples, it will be apparent after understanding the disclosure of the present 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 are to be understood in a descriptive sense only and not for purposes of limitation. The description of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Appropriate results may still be achieved if the described techniques are performed in a different order, and / or if the components in the described systems, architectures, devices, or circuits are combined in different ways and / or replaced or supplemented by other components or their equivalents.

[0181] Therefore, in addition to the disclosure above and all accompanying drawings, the scope of the present disclosure also includes the claims and their equivalents, that is, all variations within the scope of the claims and their equivalents should be construed as being included in the present disclosure.

Claims

1. An optical imaging system, characterized in that 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 in sequence from the object side towards the imaging surface, wherein, the first lens has a positive refractive power, and the second lens has a negative refractive power, wherein, each of the second lens and the third lens has a refractive index greater than 1.66, and wherein, the optical imaging system satisfies the following conditional expression: TTL / (2×IMG HT)<0.64, wherein, 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 of the diagonal length of the imaging surface.

2. The optical imaging system according to claim 1, wherein: Each of at least three lenses including the second lens and the third lens among the first lens to the eighth lens has a refractive index greater than 1.66, and Among the at least three lenses having a refractive index greater than 1.66, the absolute value of the focal length of the second lens is the smallest absolute value.

3. The optical imaging system according to claim 1, wherein: The fifth lens has a refractive index greater than 1.66, and wherein, the optical imaging system satisfies the following conditional expression: |v1-(v2+v3+v5)|<10, wherein, v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, v3 is the Abbe number of the third lens, and v5 is the Abbe number of the fifth lens.

4. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: 25<v1-v2<45; and 25<v1-v3<45, wherein, v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, and v3 is the Abbe number of the third lens.

5. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: 15<v1-(v2+v3)<25, wherein, v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, and v3 is the Abbe number of the third lens.

6. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: 1.3<Fno<1.6, wherein, Fno is the F-number of the optical imaging system.

7. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: 0.9<f1 / f<1.2, wherein, f1 is the focal length of the first lens, and f is the total focal length of the optical imaging system.

8. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: -3<f2 / f<-1, wherein, f2 is the focal length of the second lens, and f is the total focal length of the optical imaging system.

9. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: |f3 / f|>30, wherein, f3 is the focal length of the third lens, and f is the total focal length of the optical imaging system.

10. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: 0.3<|f1 / f2|<0.6, wherein, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.

11. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: |f1 / f3|<0.05, wherein, f1 is the focal length of the first lens, and f3 is the focal length of the third lens.

12. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: |f2 / f3|<0.08, wherein, f2 is the focal length of the second lens, and f3 is the focal length of the third lens.

13. The optical imaging system according to claim 1, wherein: Satisfies the following conditional expression: 1.3<f12 / f<1.7, Wherein, f12 is the composite focal length of the first lens and the second lens, and f is the total focal length of the optical imaging system.

14. The optical imaging system according to claim 13, wherein: The following conditional expressions are met: 1.3 <f123 / f<1.7, Wherein, f123 is the composite focal length of the first lens to the third lens.

15. The optical imaging system according to claim 1, wherein: The fourth lens has positive refractive power, and the fifth lens has negative refractive power.

16. The optical imaging system according to claim 1, wherein: The sixth lens has positive refractive power, the seventh lens has positive refractive power, and the eighth lens has negative refractive power.

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