CN114859521A - Optical imaging system - Google Patents

Abstract

An optical imaging system is provided. The optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens that are arranged in this order from an object side to an imaging side. The first lens has a positive refractive power and the second lens has a negative refractive power. TTL >10.2mm, and TTL/(2 × IMG HT) ≦ 1.7, where TTL is a distance from an object side surface of the first lens to an imaging plane on an optical axis, and IMG HT is equal to half a diagonal length of the imaging plane.

Description

Optical imaging system

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority from Korean Patent Application No. 10-2021-0132520 filed in the Korean Intellectual Property Office on October 6, 2021, the entire disclosure of which is incorporated herein by reference for all Purpose.

technical field

The following description refers to optical imaging systems.

Background technique

The portable terminal may include a camera including an optical imaging system combined with a plurality of lenses to perform operations such as, but not limited to, video calling and image capture.

As operations performed by cameras included in portable terminals gradually increase, the demand for high-resolution cameras for portable terminals increases.

Image sensors with high pixel counts (eg, 13 to 100 million pixels, etc.) can be used for incorporation into cameras in portable terminals to achieve improved image quality.

In addition, since the portable terminal can be implemented to have a small size, the camera provided in the portable terminal can also be implemented to have a reduced size, and therefore, it may be desirable to develop a development that can achieve high resolution while having a reduced size rate of optical imaging systems.

The above information is presented as background information only to assist in an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above may be considered prior art with regard to the present disclosure.

SUMMARY OF THE INVENTION

This Summary is provided to introduce a selection of inventive concepts in a simplified form that are further described in the Detailed Description section below. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be an aid in determining the scope of the claimed subject matter.

In a general aspect, an optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in this order from the object side to the imaging side, wherein: the first lens has positive refractive power, and the second lens The lens has negative refractive power; and TTL>10.2mm, and TTL/(2×IMG HT)≤1.7, 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 equal to the imaging plane half the length of the diagonal.

In the optical imaging system, IMG HT ≥ 4.5mm, where f is the total focal length of the optical imaging system.

n2+n3>3.20, where n2 is the refractive index of the second lens, and n3 is the refractive index of the third lens.

|f/f1+f/f2|<1.2, where f is the overall focal length of the optical imaging system, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.

BFL/f<0.4, where f is the total focal length of the optical imaging system, and BFL is the distance from the image side of the fifth lens to the imaging surface on the optical axis.

0.80≤TTL/f≤1.05, where f is the total focal length of the optical imaging system.

0≤D1/f≤0.05, where f is the total focal length of the optical imaging system, and D1 is the distance on the optical axis between the image side of the first lens and the object side of the second lens.

R1/f≦0.35, where f is the overall focal length of the optical imaging system, and R1 is the radius of curvature of the object side of the first lens.

The third lens may have positive refractive power, the fourth lens may have negative refractive power, and the fifth lens may have negative refractive power.

The third lens may have positive refractive power, the fourth lens may have positive refractive power, and the fifth lens may have negative refractive power.

The third lens may have negative refractive power, the fourth lens may have positive refractive power, and the fifth lens may have negative refractive power.

The optical imaging system may further include a sixth lens disposed between the fifth lens and the imaging surface, wherein: the third lens has positive refractive power, the fourth lens has positive refractive power, the fifth lens has negative refractive power, and the sixth lens has negative refractive power refractive power.

The optical imaging system may further include a sixth lens disposed between the fifth lens and the imaging surface, wherein: the third lens has positive refractive power, the fourth lens has positive refractive power, the fifth lens has positive refractive power, and the sixth lens has negative refractive power refractive power.

The refractive index of at least one of the second lens and the third lens may be greater than 1.64.

The absolute value of the focal length of each of the first lens and the second lens may be smaller than the absolute value of the focal length of each of the third lens, the fourth lens and the fifth lens.

Other features and aspects will become apparent from the appended claims, drawings and the following detailed description.

Description of drawings

FIG. 1 is a diagram illustrating an exemplary optical imaging system according to a first exemplary embodiment.

FIG. 2 is a graph showing aberration characteristics of the exemplary optical imaging system shown in FIG. 1 .

FIG. 3 is a diagram illustrating an exemplary optical imaging system according to the second exemplary embodiment.

FIG. 4 is a graph showing aberration characteristics of the exemplary optical imaging system shown in FIG. 3 .

FIG. 5 is a diagram illustrating an exemplary optical imaging system according to a third exemplary embodiment.

FIG. 6 is a graph showing aberration characteristics of the exemplary optical imaging system shown in FIG. 5 .

FIG. 7 is a diagram illustrating an exemplary optical imaging system according to a fourth exemplary embodiment.

FIG. 8 is a graph showing aberration characteristics of the exemplary optical imaging system shown in FIG. 7 .

FIG. 9 is a diagram illustrating an exemplary optical imaging system according to a fifth exemplary embodiment.

FIG. 10 is a graph showing aberration characteristics of the exemplary optical imaging system shown in FIG. 9 .

FIG. 11 is a diagram illustrating an exemplary optical imaging system according to the sixth exemplary embodiment.

FIG. 12 is a graph showing aberration characteristics of the exemplary optical imaging system shown in FIG. 11 .

FIG. 13 is a diagram illustrating an exemplary optical imaging system according to the seventh exemplary embodiment.

FIG. 14 is a graph showing aberration characteristics of the exemplary optical imaging system shown in FIG. 13 .

FIG. 15 is a diagram showing an example of including a reflective member in the exemplary optical imaging system shown in FIG. 1 .

16 is a plan view illustrating a non-circular lens of an exemplary optical imaging system according to an exemplary embodiment.

The same reference numerals refer to the same elements throughout the drawings and the detailed description. The figures may not be drawn to scale and the relative sizes, proportions and depictions of elements in the figures may be exaggerated for purposes of clarity, illustration and convenience.

Detailed ways

The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatus and/or systems described herein. However, various changes, modifications and equivalents of the methods, apparatus and/or systems described herein will be apparent upon understanding of the disclosure of the present application. For example, the order of operations described herein is merely an example and is not limited to the order set forth herein, except that the operations must occur in a particular order, but may be as will become apparent upon understanding the disclosure of this application Change it that way. Furthermore, descriptions of features that are known after an understanding of the present disclosure may be omitted for increased clarity and conciseness, but it should be noted that omitting features and their descriptions is not an admission that they are common general knowledge.

The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided merely to illustrate some of the many possible ways of implementing the methods, apparatus and/or systems described herein that will become apparent after an understanding of the disclosure of the present application.

It should be noted that, herein, use of the word "may" with respect to an implementation or example (eg, with respect to what an implementation or example may include or implement) means that there is at least one implementation or example in which such a feature is included or implemented , and all implementations and examples are not limited thereto.

Throughout the specification, when an element such as a layer, region or substrate is described as being "on", "connected to" or "coupled to" another element, the element can be directly on the other element ", directly "connected to", or directly "coupled to" another element, or one or more other elements may be present between the element and the other element. In contrast, when an element is described as being "directly on," "directly connected to," or "directly coupled to" another element, there is no intervening element between the element and the other element. other components.

As used herein, the term "and/or" includes any one and any combination of any two or more of the associated listed items.

Although terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, layers or sections, these elements, components, regions, layers or sections are not affected by These wording restrictions. Rather, these terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, reference to a first member, component, region, layer or portion in these examples could also be termed a second member, A second component, a second region, a second layer or a second portion.

Spatially relative terms such as "above," "above," "below," and "lower" may be used herein for descriptive convenience to describe one such as that shown in the accompanying drawings. The relationship of an element to another element. In addition to encompassing the orientations depicted in the figures, these spatially relative terms are intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is turned over, elements described as "above" or "above" another element would then be oriented "below" or relative to the other element "Lower". Thus, depending on the spatial orientation of the device, the wording "above" covers both orientations "above" and "below". The device may also be oriented in other ways (eg, rotated 90 degrees or at other orientations) and the spatially relative phraseology used herein should be interpreted accordingly.

The terminology used herein is only used to describe various examples, not to limit the present disclosure. The articles "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The words "comprising", "comprising" and "having" describe the presence of stated features, numbers, operations, components, elements and/or combinations thereof, but do not exclude one or more other features, numbers, operations, components, elements and The presence or addition of/or combinations thereof.

Variations from the shapes shown in the figures may occur due to manufacturing techniques and/or tolerances. Accordingly, the examples described herein are not limited to the specific shapes shown in the drawings, but include shape variations that occur during manufacture.

The features of the examples described herein may be combined in various ways that will become apparent after gaining an understanding of the disclosure of the present application. Furthermore, while the examples described herein have a variety of configurations, other configurations are possible that will become apparent after gaining an understanding of the disclosure of the present application.

Hereinafter, examples of the present disclosure will be described as follows with reference to the accompanying drawings.

One or more examples provide optical imaging systems that can achieve high resolution.

In the lens diagrams, the thickness, size and shape of the lenses are exaggerated, and in particular, the shapes of spherical surfaces or aspherical surfaces presented in the lens diagrams are only examples, but not limited thereto.

The optical imaging system according to the exemplary embodiment may include a plurality of lenses arranged along the optical axis. The plurality of lenses may be spaced apart from each other by a predetermined distance along the optical axis.

As an example, the optical imaging system includes five or six lenses.

Among the lenses included in the optical imaging system, the frontmost lens may refer to the lens closest to the object side (or the reflective member), and the last lens may refer to the lens closest to the imaging surface (or image sensor).

As an example, in an embodiment in which the optical imaging system includes five lenses, the first lens may refer to the lens closest to the object side (or reflective member), and the fifth lens may refer to the lens closest to the imaging surface (or image sensor) .

In embodiments where the optical imaging system includes six lenses, the first lens may refer to the lens closest to the object side (or reflective member), and the sixth lens may refer to the lens closest to the imaging surface (or image sensor). Additionally, in exemplary embodiments, the radius of curvature, thickness, distance, and focal length of the lenses are expressed in millimeters (mm), and the field of view (FOV) is expressed in degrees.

In the description of the shape of each lens, a configuration in which one face is convex indicates that the paraxial region portion or paraxial region of the face is convex, and a configuration in which one face is concave indicates the paraxial region portion of the face. Either the paraxial region is concave, and a configuration in which one of the faces is flat means that the paraxial region portion of the face or the paraxial region is flat. Thus, when one face of the lens is described as convex, the edge portion of the lens may be concave. Similarly, when one face of the lens is described as concave, the edge portion of the lens may be convex. Additionally, when one face of the lens is described as being flat, the edge portion of the lens may be convex or concave.

A paraxial region may refer to a significantly narrow region adjacent to the optical axis.

The imaging plane may refer to the virtual plane on which the in-focus image is formed by the optical imaging system. Alternatively, the imaging surface may refer to a surface of the image sensor on which light is received.

The optical imaging system in the exemplary embodiment may include six lenses.

In an example, the optical imaging system in the exemplary embodiment may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in this order from the object side to the imaging side. The first to sixth lenses may be spaced apart from each other by a predetermined distance along the optical axis.

An optical imaging system in another exemplary embodiment may include five lenses.

For example, the optical imaging system in the exemplary embodiment may include a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in this order from the object side to the imaging side. The first to fifth lenses may be spaced apart from each other by a predetermined distance along the optical axis.

However, the optical imaging system in the exemplary embodiment may include not only five lenses or six lenses, but may further include other components as required.

For example, referring to FIG. 15, the optical imaging system may further include a reflective member having a reflective surface that changes the path of the light. The reflective member may be configured to change the optical member by 90 degrees (by way of example only). As an example, the reflective member may be implemented as a mirror or a prism.

The reflection member may be disposed in front of the plurality of lenses. As an example, the reflective member may be disposed in front of the first lens (eg, closer to the object side than the first lens). Thus, in one or more examples, the lens disposed closest to the object side may be the lens disposed closest to the reflective member.

The optical imaging system may also include an image sensor that converts an incident image of the subject into electrical signals.

The optical imaging system may also include an infrared cut filter (hereinafter referred to as a "filter") that blocks infrared rays. The filter may be disposed between the lens (the fifth lens or the sixth lens) disposed closest to the imaging plane and the imaging plane.

The optical imaging system may further include a diaphragm that adjusts the amount of light.

All lenses included in the optical imaging system of the exemplary embodiments may be formed of plastic materials.

Furthermore, each lens may be formed of a plastic material having optical properties different from those of the adjacent lenses.

16, at least some of the lenses of the optical imaging system may have a non-circular planar shape. In an example, the frontmost lens and the rearmost lens may have non-circular planar shapes. Other lenses may have non-circular planar shapes or circular planar shapes.

The non-circular lens may have four side surfaces, and the two side surfaces are formed to be opposed to each other. Furthermore, the side surfaces opposite to each other may have corresponding shapes.

In an example, the first lens may have a first side surface, a second side surface, a third side surface, and a fourth side surface. The first side surface and the second side surface are arranged to face each other with respect to the optical axis, and the third side surface and the fourth side surface are arranged to face each other with respect to the optical axis. Each of the third side surface and the fourth side surface may connect the first side surface and the second side surface.

The first and second side surfaces of the first lens may have arcuate shapes, and the third and fourth side surfaces may have substantially linear shapes when viewed in the optical axis direction.

Each of the third side surface and the fourth side surface may connect the first side surface and the second side surface. Also, the third side surface and the fourth side surface may be symmetrical with respect to the optical axis, and may be formed parallel to each other.

The non-circular lens may have a first axis and a second axis that intersect the optical axis. In an example, the first axis may be an axis connecting the first side surface and the second side surface while passing through the optical axis, and the second axis may be an axis connecting the third side surface and the fourth side surface while passing through the optical axis The axis of the side surface. The first axis and the second axis may be perpendicular to each other, and the length of the first axis may be greater than the length of the second axis.

In an example, the first lens may have two axes that intersect the optical axis and are perpendicular to each other, and a length of one of the two axes may be greater than a length of the other of the two axes.

Referring to FIG. 16 , all lenses of the optical imaging system may include the optical portion 10 and the flange portion 30 .

The optical portion 10 may be a portion in which the optical properties of the lens are exhibited. In an example, light reflected from an object may be refracted as it passes through the optical portion 10 .

The optical portion 10 may have refractive power and may have an aspherical shape.

In addition, the optical portion 10 may have an object side (surface facing the object side) and an image side (surface facing the imaging side) (the object side is shown in FIG. 16 ).

The flange portion 30 may be a portion that secures the lens to another component (eg, a lens barrel or another lens).

The flange portion 30 may extend from the periphery of at least a portion of the optical portion 10 and may be formed integrally with the optical portion 10 .

In a non-circular lens, the optical portion 10 and the flange portion 30 may be formed in a non-circular shape. In an example, the optical portion 10 and the flange portion 30 may be non-circular when viewed in the optical axis direction (see FIG. 16 ). Alternatively, the optical portion 10 may be formed to be circular, and the flange portion 30 may be formed to be non-circular.

The optical portion 10 may include a first edge 11 , a second edge 12 , a third edge 13 and a fourth edge 14 . The first edge 11 and the second edge 12 may be arranged opposite to each other, and the third edge 13 and the fourth edge 14 may be arranged opposite to each other.

Each of the third edge 13 and the fourth edge 14 may connect the first edge 11 and the second edge 12 .

The first edge 11 and the second edge 12 may be arranged opposite to each other with respect to the optical axis, and the third edge 13 and the fourth edge 14 may be arranged opposite to each other with respect to the optical axis.

When viewed in the optical axis direction, the first edge 11 and the second edge 12 may have an arc shape, and the third edge 13 and the fourth edge 14 may have a substantially linear shape. The third edge 13 and the fourth edge 14 may be formed to be symmetrical with respect to the optical axis (Z axis) and parallel to each other.

The shortest distance between the first edge 11 and the second edge 12 may be greater than the shortest distance between the third edge 13 and the fourth edge 14 .

The optical portion 10 may have a long axis "a" and a short axis "b". In an example, when viewed from the optical axis direction, a line segment connecting the third edge 13 and the fourth edge 14 at the shortest distance while passing through the optical axis may be the short axis "b", and when passing through the optical axis and perpendicular to The line segment connecting the first edge 11 and the second edge 12 at the same time as the short axis "b" may be the long axis "a".

In this example, half of the major axis "a" may be the maximum effective radius and half of the minor axis "b" may be the minimum effective radius.

Assuming that the lens shown in FIG. 16 is the frontmost lens (eg, the first lens), the maximum effective radius of the object side of the frontmost lens is the reference numeral L1S1el of FIG. 16 , and the minimum effective radius of the object side of the frontmost lens is the Reference numeral L1S1es.

The flange portion 30 may include a first flange portion 31 and a second flange portion 32 . The first flange portion 31 may extend from the first edge 11 of the optical portion 10 and the second flange portion 32 may extend from the second edge 12 of the optical portion 10 .

The first edge 11 of the optical portion 10 may refer to a portion adjacent to the first flange portion 31 , and the second edge 12 of the optical portion 10 may refer to a portion adjacent to the second flange portion 32 .

The third edge 13 of the optical portion 10 may refer to one side surface of the optical portion 10 where the flange portion 30 is not formed, and the fourth edge 14 of the optical portion 10 may refer to the other side of the optical portion 10 where the flange portion 30 is not formed surface or the opposite side surface.

The effective radius of each of the first lens and the fifth lens may be larger than that of each of the other lenses.

The term "effective radius" refers to the radius of one face (object side and image side) of each lens through which light actually passes. In an example, the term "effective radius" may refer to the radius of the optical portion of each lens.

A non-circular lens can have a maximum effective radius (half a line connecting the first edge 11 and the second edge 12 while passing through the optical axis) and a minimum effective radius (connecting the third edge 13 and the second edge while passing through the optical axis). half of the straight line of the fourth edge 14).

In one or more examples, unless otherwise stated, the term "effective radius" may refer to the maximum effective radius.

Each of the plurality of lenses may have at least one aspherical surface.

That is, at least one of the first and second surfaces of each lens may be an aspherical surface. The aspheric surface of each lens is represented as follows:

Equation 1:

In Equation 1, c is the curvature of the lens (the inverse of the radius of curvature), K is the conic constant, and Y is the distance from a point on the aspheric surface of the lens to the optical axis in the direction perpendicular to the optical axis. In addition, the constants A to J are aspheric coefficients. Z is the distance in the direction of the optical axis from a point on the aspheric surface of the lens to the vertex of the aspheric surface.

The optical imaging system including the first lens to the sixth lens may have positive refractive power, negative refractive power, positive refractive power, positive refractive power, negative refractive power, and negative refractive power, respectively, from the object side to the imaging side, or may be sequentially from the object side to the imaging side, respectively. Has positive refractive power, negative refractive power, positive refractive power, positive refractive power, positive refractive power, and negative refractive power.

The optical imaging system including the first lens to the fifth lens may have positive refractive power, negative refractive power, positive refractive power, negative refractive power, and negative refractive power, respectively, from the object side to the imaging side, or may have positive refractive power, respectively, from the object side to the imaging side, respectively , negative refractive power, positive refractive power, positive refractive power, and negative refractive power, or may have positive refractive power, negative refractive power, negative refractive power, positive refractive power, and negative refractive power, respectively, from the object side to the imaging side, respectively.

The optical imaging system in the exemplary embodiment may satisfy at least one of the following conditional expressions:

Conditional expression 1: TTL>10.2mm

Conditional expression 2: 10.2mm<TTL<16mm

Conditional expression 3: TTL/(2x IMG HT)≤1.7

Conditional expression 4: 1.2<TTL/(2x IMG HT)≤1.7

Conditional Expression 5: 1.5<f/IMG HT<3.5

Conditional expression 6: IMG HT ≥ 4.5mm

Conditional expression 7: n2+n3>3.20

Conditional expression 8: |f/f1+f/f2|<1.2

Conditional expression 9: 0≤D1/f≤0.05

Conditional expression 10: 0.80≤TTL/f≤1.05

Conditional Expression 11: R1/f≤0.35

Conditional Expression 12: BFL/f<0.4

In the conditional expression, f is the total focal length of the optical imaging system, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.

In the conditional expression, n2 is the refractive index of the second lens, and n3 is the refractive index of the third lens.

In the conditional expression, TTL is the distance on the optical axis from the object side of the frontmost lens or the first lens to the imaging plane, and BFL is the distance on the optical axis from the image side of the last lens to the imaging plane.

In the conditional expression, D1 is the distance on the optical axis between the image side of the first lens and the object side of the second lens, R1 is the radius of curvature of the object side of the first lens, and IMG HT is equal to the pair of image surfaces half the length of the corner.

The optical imaging system in the exemplary embodiment may have characteristics of a telephoto lens having a relatively narrow field of view and a relatively long focal length.

Additionally, the optical imaging system in the exemplary embodiments may be configured to have a relatively large diagonal length of the imaging plane. In an example, the effective imaging area of the image sensor may be wide (eg, a high pixel image sensor).

Therefore, when cropping the captured image, images of various magnifications can be captured without degrading the image quality.

At least one of the second lens and the third lens may have a refractive index greater than 1.64.

The absolute value of the focal length of each of the first lens and the second lens may be smaller than the absolute value of the focal length of each of the other lenses.

An optical imaging system according to the first exemplary embodiment will be described with reference to FIGS. 1 and 2 .

The optical imaging system 100 in the first exemplary embodiment may include an optical system including a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, and a sixth lens The lens 160, and may also include the filter 170 and the image sensor IS.

The optical imaging system 100 in the first exemplary embodiment can form a focused image on the imaging plane 180 of the image sensor IS. Imaging surface 180 may refer to the surface on which a focused image is formed by optical imaging system 100 . In an example, the imaging surface 180 may refer to a surface of the image sensor IS on which light is received.

Although not shown in FIG. 1 , the optical imaging system 100 may further include a reflective member R (see FIG. 15 ) that is disposed in front of the first lens 110 and has a reflective surface that changes the path of light. In the first exemplary embodiment, the reflecting member R may be a prism, but may also be implemented as a reflecting mirror.

The lens properties of each lens (radius of curvature, thickness of lenses or distance between lenses, refractive index, Abbe number, and focal length) are listed in Table 1 below.

Table 1

The overall focal length f of the optical imaging system in the first exemplary embodiment is 15 mm, and the IMG HT is 5.128 mm.

In the first exemplary embodiment, the first lens 110 may have positive refractive power, the first surface of the first lens 110 may be convex, and the second surface of the first lens 110 may also be convex.

The second lens 120 may have negative refractive power, the first face of the second lens 120 may be convex, and the second face of the second lens 120 may be concave.

The third lens 130 may have positive refractive power, the first face of the third lens 130 may be convex, and the second face of the third lens 130 may be concave.

The fourth lens 140 may have positive refractive power, the first face of the fourth lens 140 may be convex, and the second face of the fourth lens 140 may be concave.

The fifth lens 150 may have negative refractive power, the first face of the fifth lens 150 may be convex, and the second face of the fifth lens 150 may be concave.

The sixth lens 160 may have negative refractive power, the first face of the sixth lens 160 may be convex in the paraxial region, and the second face of the sixth lens 160 may be concave in the paraxial region.

In addition, the sixth lens 160 may have at least one inflection point formed on at least one of the first face and the second face. In an example, the second face of the sixth lens 160 may be concave in a paraxial region and convex in a portion other than the paraxial region.

Each face of the first lens 110 to the sixth lens 160 may have aspheric coefficients listed in Table 2 below. In an example, the object side and the image side of the first to sixth lenses 110 to 160 may be aspherical.

Table 2

The optical imaging system 100 configured as described above may have the aberration characteristics shown in FIG. 2 .

An optical imaging system according to the second exemplary embodiment will be described with reference to FIGS. 3 and 4 .

The optical imaging system 200 in the second exemplary embodiment may include an optical system including a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, and a sixth lens The lens 260, and may also include the filter 270 and the image sensor IS.

The optical imaging system 200 in the second exemplary embodiment can form a focused image on the imaging plane 280 . The imaging surface 280 may refer to the surface of the image sensor IS on which the in-focus image is formed by the optical imaging system 200 . In an example, the imaging surface 280 may refer to a surface of the image sensor IS on which light is received.

Although not shown in FIG. 3 , the optical imaging system 200 may further include a reflective member R (see FIG. 15 ) disposed in front of the first lens 210 and having a reflective surface that changes the path of light. In the second exemplary embodiment, the reflecting member R may be a prism, but may also be implemented as a reflecting mirror.

The lens properties of each lens (radius of curvature, thickness of lenses or distance between lenses, refractive index, Abbe number, and focal length) are listed in Table 3 below.

table 3

face number mark Radius of curvature thickness or distance refractive index Abbe number focal length S1 first lens 4.9489607 2.000 1.537 55.7 9.14375 S2 -556.8638 0.050 S3 second lens 35.489609 0.650 1.646 23.5 -8.68276 S4 4.8058549 1.500 S5 third lens 4.0957987 0.722 1.679 19.2 44.0122 S6 4.4080644 0.300 S7 fourth lens 4.9340121 0.614 1.537 55.7 29.4635 S8 6.8575524 0.500 S9 Fifth lens 6.794379 0.775 1.646 23.5 144.143 S10 7.0017622 3.797 S11 sixth lens 5.0156608 0.800 1.537 55.7 -54.7209 S12 4.0457338 3.000 S13 filter gigantic 0.210 1.519 64.2 S14 gigantic 0.813 S15 Imaging plane gigantic

The overall focal length f of the optical imaging system in the second exemplary embodiment is 15 mm, and the IMG HT is 5.4 mm.

In the second exemplary embodiment, the first lens 210 may have positive refractive power, and the first surface of the first lens 210 and the second surface of the first lens 210 may also be convex.

The second lens 220 may have negative refractive power, the first face of the second lens 220 may be convex, and the second face of the second lens 220 may be concave.

The third lens 230 may have positive refractive power, the first surface of the third lens 230 may be convex, and the second surface of the third lens 230 may be concave.

The fourth lens 240 may have positive refractive power, the first face of the fourth lens 240 may be convex, and the second face of the fourth lens 240 may be concave.

The fifth lens 250 may have positive refractive power, the first face of the fifth lens 250 may be convex, and the second face of the fifth lens 250 may be concave.

The sixth lens 260 may have negative refractive power, the first face of the sixth lens 260 may be convex in the paraxial region, and the second face of the sixth lens 260 may be concave in the paraxial region.

In addition, the sixth lens 260 may have at least one inflection point formed on at least one of the first face and the second face. In an example, the first face of the sixth lens 260 may be convex in a paraxial region and concave in a portion or region other than the paraxial region. In addition, the second face of the sixth lens 260 may be concave in the paraxial region and convex in a portion or region other than the paraxial region.

Each of the surfaces of the first to sixth lenses 210 to 260 may have aspheric coefficients as shown in Table 4 below. In an example, both the object side and the image side of the first lens 210 to the sixth lens 260 may be aspherical.

Table 4

S1 S2 S3 S4 S5 S6 Conic constant (K) -0.67258 -99.00000 97.49800 0.00000 0.00000 -0.07552 4th order coefficient (A) 1.5128E-05 2.2191E-04 -6.5288E-05 -1.1672E-03 -5.5861E-04 -8.1068E-04 6th order coefficient (B) -1.5868E-05 -7.7041E-06 1.6242E-05 -5.8934E-05 -4.6455E-05 -2.2661E-05 8th order coefficient (C) -1.0719E-06 -9.8215E-07 -9.0232E-07 2.7014E-07 -1.8291E-08 -1.9193E-06 10th order coefficient (D) -4.0847E-08 -9.5109E-08 -1.2800E-07 1.9644E-07 3.5870E-07 2.5331E-08 12th order coefficient (E) -1.5147E-09 -4.2905E-09 -1.3036E-08 -1.2270E-08 2.9772E-08 1.9633E-07 14th order coefficient (F) -2.8803E-11 -1.9582E-10 -8.6113E-10 -4.2051E-09 6.5213E-09 4.5778E-08 16th order coefficient (G) 4.5059E-12 -2.7803E-11 -3.7076E-11 -7.5074E-10 5.2618E-10 4.1697E-09 18th order coefficient (H) -9.5468E-13 1.8389E-12 3.6135E-13 -5.5324E-11 2.0863E-11 -1.7698E-10 20th order coefficient (J) 2.5397E-14 1.6251E-13 3.2132E-13 1.1687E-11 -1.7045E-11 -2.1568E-10 S7 S8 S9 S10 S11 S12 Conic constant (K) 0.26498 -0.92638 -2.57360 1.02810 -8.37140 -5.03820 4th order coefficient (A) -9.9991E-04 -3.6957E-04 -1.9038E-03 -1.3893E-03 -4.0396E-03 -4.6693E-03 6th order coefficient (B) 8.2990E-05 7.6680E-05 -6.8259E-05 2.0829E-04 -1.1804E-04 1.7996E-05 8th order coefficient (C) 1.3755E-05 3.2877E-05 -3.0848E-06 -3.7592E-05 1.1598E-05 7.6129E-06 10th order coefficient (D) 4.8742E-06 6.5958E-06 -4.1405E-06 -6.7933E-06 4.8391E-07 1.3341E-08 12th order coefficient (E) 5.8840E-07 4.2469E-07 -6.8348E-07 2.3833E-07 -1.5465E-08 -2.4877E-08 14th order coefficient (F) 6.6712E-08 5.1166E-08 -3.2432E-08 6.8499E-09 -3.7533E-09 -9.9716E-10 16th order coefficient (G) 6.4327E-09 5.9823E-09 4.1342E-09 -4.1045E-09 1.3933E-14 1.9553E-10 18th order coefficient (H) 2.0057E-10 4.6032E-11 1.9997E-09 2.2852E-09 -3.0871E-12 -1.1070E-11 20th order coefficient (J) -3.2966E-10 -1.1904E-10 -1.4404E-10 -1.1245E-10 8.2208E-13 2.8425E-13

In addition, the optical imaging system 200 configured as described above may have the aberration characteristics shown in FIG. 4 .

The optical imaging system 300 according to the third exemplary embodiment will be described with reference to FIGS. 5 and 6 .

The optical imaging system 300 in the third exemplary embodiment may include an optical system including a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, and a fifth lens 350, and further The filter 370 and the image sensor IS may be included.

The optical imaging system 300 in the third exemplary embodiment can form a focused image on the imaging surface 380 of the image sensor IS. Imaging surface 380 may refer to the surface on which a focused image is formed by optical imaging system 300 . In an example, the imaging surface 380 may refer to a surface of the image sensor IS on which light is received.

Although not shown in FIG. 5 , the optical imaging system 300 may further include a reflective member R (see FIG. 15 ) that is disposed in front of the first lens 310 and has a reflective surface that changes the path of light. In the third exemplary embodiment, the reflecting member R may be a prism, but may also be implemented as a reflecting mirror.

The lens properties of each lens (radius of curvature, thickness of lenses or distance between lenses, refractive index, Abbe number, and focal length) are listed in Table 5 below.

table 5

face number mark Radius of curvature thickness or distance refractive index Abbe number focal length S1 first lens 4.2994663 2.000 1.537 55.7 6.523 S2 -15.76502 0.050 S3 second lens -16.46547 0.500 1.646 23.5 -5.98498 S4 5.0925379 0.957 S5 third lens 4.2766847 1.155 1.679 19.2 8.981 S6 13.358993 0.050 S7 fourth lens 5.7826016 0.400 1.537 55.7 -18.6452 S8 3.8549855 3.389 S9 Fifth lens 7.9053798 0.500 1.646 23.5 -31.2964 S10 5.2564001 3.000 S11 filter gigantic 0.210 1.519 64.2 S12 gigantic 1.887 S13 Imaging plane gigantic

The overall focal length f of the optical imaging system 300 in the third exemplary embodiment is 15 mm, and the IMG HT is 5.4 mm.

In the third exemplary embodiment, the first lens 310 may have positive refractive power, the first surface of the first lens 310 may be convex, and the second surface of the first lens 310 may be convex.

The second lens 320 may have negative refractive power, the first face of the second lens 320 may be concave, and the second face of the second lens 320 may be concave.

The third lens 330 may have positive refractive power, the first face of the third lens 330 may be convex, and the second face of the third lens 330 may be concave.

The fourth lens 340 may have negative refractive power, the first face of the fourth lens 340 may be convex, and the second face of the fourth lens 340 may be concave.

The fifth lens 350 may have negative refractive power, the first face of the fifth lens 350 may be convex in the paraxial region, and the second face of the fifth lens 350 may be concave in the paraxial region.

In addition, the fifth lens 350 may have at least one inflection point formed on at least one of the first face and the second face. In an example, the first face of the fifth lens 350 may be convex in the paraxial region and concave in a portion or region other than the paraxial region. The second face of the fifth lens 350 may be concave in the paraxial region and convex in a portion or region other than the paraxial region.

Each face of the first lens 310 to the fifth lens 350 may have aspheric coefficients as shown in Table 6 below. In an example, both the object side and the image side of the first lens 310 to the fifth lens 350 may be aspherical.

Table 6

The optical imaging system 300 configured as described above may have the aberration characteristics shown in FIG. 6 .

An optical imaging system 400 according to the fourth exemplary embodiment will be described with reference to FIGS. 7 and 8 .

The optical imaging system 400 in the fourth exemplary embodiment may include an optical system including a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, and a fifth lens 450, and further The filter 470 and the image sensor IS may be included.

The optical imaging system 400 in the fourth exemplary embodiment can form a focused image on the imaging surface 480 of the image sensor IS. Imaging surface 480 may refer to the surface on which a focused image is formed by optical imaging system 400 . As an example, the imaging surface 480 may refer to a surface of the image sensor IS on which light is received.

Although not shown in FIG. 7 , the optical imaging system 400 may further include a reflective member R (see FIG. 15 ) that is disposed in front of the first lens 410 and has a reflective surface that changes the path of light. In the fourth exemplary embodiment, the reflecting member R may be a prism, but may also be implemented as a reflecting mirror.

The lens properties of each lens (radius of curvature, thickness of lenses or distance between lenses, refractive index, Abbe number, and focal length) are listed in Table 7 below.

Table 7

The overall focal length f of the optical imaging system 400 in the fourth exemplary embodiment is 14.9997 mm, and the IMG HT is 5.4 mm.

In the fourth exemplary embodiment, the first lens 410 may have positive refractive power, the first surface of the first lens 410 may be convex, and the second surface of the first lens 410 may be convex.

The second lens 420 may have negative refractive power, the first face of the second lens 420 may be concave, and the second face of the second lens 420 may be concave.

The third lens 430 may have positive refractive power, the first face of the third lens 430 may be convex, and the second face of the third lens 430 may be concave.

The fourth lens 440 may have negative refractive power, the first face of the fourth lens 440 may be convex, and the second face of the fourth lens 440 may be concave.

The fifth lens 450 may have negative refractive power, the first face of the fifth lens 450 may be convex in the paraxial region, and the second face of the fifth lens 450 may be concave in the paraxial region.

In addition, the fifth lens 450 may have at least one inflection point formed on at least one of the first face and the second face. In an example, the first face of the fifth lens 450 may be convex in the paraxial region and concave in a portion or region other than the paraxial region. The second face of the fifth lens 450 may be concave in the paraxial region and convex in a portion or region other than the paraxial region.

Each face of the first lens 410 to the fifth lens 450 may have aspheric coefficients as shown in Table 8 below. In an example, both the object side and the image side of the first lens 410 to the fifth lens 450 may be aspherical.

Table 8

In addition, the optical imaging system 400 configured as described above may have the aberration characteristics shown in FIG. 8 .

An optical imaging system 500 according to the fifth exemplary embodiment will be described with reference to FIGS. 9 and 10 .

The optical imaging system 500 in the fifth exemplary embodiment may include an optical system including a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, and a fifth lens 550, and further The filter 570 and the image sensor IS may be included.

The optical imaging system 500 in the fifth exemplary embodiment can form a focused image on the imaging surface 580 of the image sensor IS. Imaging surface 580 may refer to the surface on which a focused image is formed by optical imaging system 500 . In an example, the imaging surface 580 may refer to a surface of the image sensor IS on which light is received.

Although not shown in FIG. 9 , the optical imaging system 500 may further include a reflective member R (see FIG. 15 ) that is disposed in front of the first lens 510 and has a reflective surface that changes the path of light. In the fifth exemplary embodiment, the reflecting member R may be a prism, but may also be implemented as a reflecting mirror.

The lens properties of each lens (radius of curvature, thickness of the lenses or distance between lenses, refractive index, Abbe number, and focal length) are listed in Table 9.

Table 9

face number mark Radius of curvature thickness or distance refractive index Abbe number focal length S1 first lens 4.40444 1.954 1.537 55.7 6.880 S2 -19.2806 0.120 S3 second lens -17.4567 0.666 1.644 23.5 -6.91172 S4 6.06424 1.000 S5 third lens 5.08995 0.863 1.656 21.5 17.847 S6 8.40284 0.374 S7 fourth lens 7.00548 0.554 1.667 20.4 130.743 S8 7.37695 2.800 S9 Fifth lens 14.4676 0.676 1.537 55.7 -19.9373 S10 6.05004 3.000 S11 filter gigantic 0.210 1.518 64.2 S12 gigantic 1.883 S13 Imaging plane gigantic

The total focal length f of the optical imaging system 500 according to the fifth exemplary embodiment is 15 mm, and the IMG HT is 5.128 mm.

In the fifth exemplary embodiment, the first lens 510 may have positive refractive power, the first surface of the first lens 510 may be convex, and the second surface of the first lens 510 may be convex.

The second lens 520 may have negative refractive power, the first face of the second lens 520 may be concave, and the second face of the second lens 520 may be concave.

The third lens 530 may have positive refractive power, the first surface of the third lens 530 may be convex, and the second surface of the third lens 530 may be concave.

The fourth lens 540 may have positive refractive power, the first face of the fourth lens 540 may be convex, and the second face of the fourth lens 540 may be concave.

The fifth lens 550 may have negative refractive power, the first face of the fifth lens 550 may be convex in the paraxial region, and the second face of the fifth lens 550 may be concave in the paraxial region.

In addition, the fifth lens 550 may have at least one inflection point formed on at least one of the first face and the second face. In an example, the first face of the fifth lens 550 may be convex in the paraxial region and concave in a portion or region other than the paraxial region. The second face of the fifth lens 550 may be concave in the paraxial region and convex in a portion or region other than the paraxial region.

Each of the surfaces of the first to fifth lenses 510 to 550 may have aspheric coefficients as shown in Table 10 below. In an example, both the object side and the image side of the first lens 510 to the fifth lens 550 may be aspherical.

Table 10

S1 S2 S3 S4 S5 Conic constant (K) -0.67151 -2.06050 -67.39700 0.51600 0.48287 4th order coefficient (A) -9.7544E-04 8.9298E-03 5.3855E-04 9.6592E-04 1.3533E-02 6th order coefficient (B) 3.7070E-03 -2.8714E-02 -2.2026E-02 -2.3244E-02 -3.6408E-02 8th order coefficient (C) -4.9650E-03 3.9580E-02 3.3095E-02 3.9136E-02 5.8110E-02 10th order coefficient (D) 4.1990E-03 -2.8768E-02 -2.4019E-02 -4.1540E-02 -6.7755E-02 12th order coefficient (E) -2.3418E-03 1.2652E-02 9.9311E-03 3.0969E-02 5.6345E-02 14th order coefficient (F) 8.9903E-04 -3.5434E-03 -2.2711E-03 -1.6822E-02 -3.3560E-02 16th order coefficient (G) -2.4448E-04 6.2316E-04 1.5889E-04 6.7901E-03 1.4514E-02 18th order coefficient (H) 4.7772E-05 -5.9034E-05 6.6690E-05 -2.0467E-03 -4.5935E-03 20th order coefficient (J) -6.7196E-06 -1.1844E-07 -2.4662E-05 4.5742E-04 1.0621E-03 S6 S7 S8 S9 S10 Conic constant (K) -1.25120 1.48320 1.75320 -95.98000 -54.35500 4th order coefficient (A) 1.8194E-02 4.6046E-02 3.1108E-02 -2.1824E-02 3.0220E-03 6th order coefficient (B) -3.4014E-02 -2.0546E-01 -1.7731E-01 -6.6542E-03 -1.8476E-02 8th order coefficient (C) 3.1043E-02 5.2291E-01 5.7733E-01 1.5928E-02 1.7662E-02 10th order coefficient (D) -1.6899E-02 -9.0013E-01 -1.2497E+00 -1.8903E-02 -1.3015E-02 12th order coefficient (E) 2.3405E-03 1.0763E+00 1.8722E+00 1.4688E-02 7.2515E-03 14th order coefficient (F) 4.7088E-03 -9.1427E-01 -1.9899E+00 -7.7684E-03 -2.9614E-03 16th order coefficient (G) -4.6141E-03 5.6129E-01 1.5263E+00 2.8613E-03 8.7898E-04 18th order coefficient (H) 2.2951E-03 -2.5123E-01 -8.5201E-01 -7.4334E-04 -1.8951E-04 20th order coefficient (J) -7.3358E-04 8.1937E-02 3.4585E-01 1.3645E-04 2.9590E-05

In addition, the optical imaging system 500 configured as described above may have the aberration characteristics shown in FIG. 10 .

An optical imaging system 600 according to the sixth exemplary embodiment will be described with reference to FIGS. 11 and 12 .

The optical imaging system 600 in the sixth exemplary embodiment may include an optical system including a first lens 610, a second lens 620, a third lens 630, a fourth lens 640, and a fifth lens 650, and further The filter 670 and the image sensor IS may be included.

The optical imaging system 600 according to the sixth exemplary embodiment can form a focused image on the imaging plane 680 of the image sensor IS. Imaging surface 680 may refer to the surface on which a focused image is formed by optical imaging system 600 . In an example, the imaging surface 680 may refer to a surface of the image sensor IS on which light is received.

Although not shown in FIG. 11 , the optical imaging system 600 may further include a reflective member R disposed in front of the first lens 610 and having a reflective surface that changes the path of light. In the sixth exemplary embodiment, the reflecting member R may be a prism, but may also be implemented as a reflecting mirror.

The lens properties of each lens (radius of curvature, thickness of lenses or distance between lenses, refractive index, Abbe number, and focal length) are listed in Table 11 below.

Table 11

face number mark Radius of curvature thickness or distance refractive index Abbe number focal length S1 first lens 4.3645 1.978 1.537 55.7 6.910 S2 -20.7455 0.130 S3 second lens -19.5126 0.604 1.644 23.5 -7.10304 S4 6.04801 1.153 S5 third lens 5.10122 0.878 1.656 21.5 17.923 S6 8.39967 0.325 S7 fourth lens 7.26265 0.500 1.667 20.4 229.705 S8 7.41438 2.800 S9 Fifth lens 14.3727 0.618 1.537 55.7 -20.4303 S10 6.12583 3.000 S11 filter gigantic 0.210 1.518 64.2 S12 gigantic 1.901 S13 Imaging plane gigantic

The overall focal length f of the optical imaging system 600 in the sixth exemplary embodiment is 15.0001 mm, and the IMG HT is 5.644 mm.

In the sixth exemplary embodiment, the first lens 610 may have positive refractive power, the first surface of the first lens 610 may be convex, and the second surface of the first lens 610 may be convex.

The second lens 620 may have negative refractive power, the first face of the second lens 620 may be concave, and the second face of the second lens 620 may be concave.

The third lens 630 may have positive refractive power, the first face of the third lens 630 may be convex, and the second face of the third lens 630 may be concave.

The fourth lens 640 may have positive refractive power, the first face of the fourth lens 640 may be convex, and the second face of the fourth lens 640 may be concave.

The fifth lens 650 may have negative refractive power, the first face of the fifth lens 650 may be convex in the paraxial region, and the second face of the fifth lens 650 may be concave in the paraxial region.

In addition, the fifth lens 650 may have at least one inflection point formed on at least one of the first face and the second face. In an example, the first face of the fifth lens 650 may be convex in a paraxial region and concave in a portion or region other than the paraxial region. The second face of the fifth lens 650 may be concave in the paraxial region and convex in a portion or region other than the paraxial region.

Each face of the first lens 610 to the fifth lens 650 may have aspheric coefficients as shown in Table 12 below. In an example, both the object side and the image side of the first lens 610 to the fifth lens 650 may be aspherical.

Table 12

In addition, the optical imaging system 600 configured as described above may have the aberration characteristics shown in FIG. 12 .

An optical imaging system 700 according to the seventh exemplary embodiment will be described with reference to FIGS. 13 and 14 .

The optical imaging system 700 in the seventh exemplary embodiment may include an optical system including a first lens 710, a second lens 720, a third lens 730, a fourth lens 740, and a fifth lens 750, and further The filter 770 and the image sensor IS may be included.

The optical imaging system 700 in the seventh exemplary embodiment can form a focused image on the imaging surface 780 of the image sensor IS. Imaging surface 780 may refer to the surface on which a focused image is formed by optical imaging system 700 . In an example, the imaging surface 780 may refer to the surface of the image sensor IS on which light is received.

Although not shown in FIG. 13 , the optical imaging system 700 may further include a reflective member R (see FIG. 15 ) that is disposed in front of the first lens 710 and has a reflective surface that changes the path of light. In the seventh exemplary embodiment, the reflecting member R may be a prism, but may also be implemented as a reflecting mirror.

The lens properties of each lens (radius of curvature, thickness of lenses or distance between lenses, refractive index, Abbe number, and focal length) are listed in Table 13 below.

Table 13

The overall focal length f of the optical imaging system 700 in the seventh exemplary embodiment is 15 mm, and the IMG HT is 5.4 mm.

In the seventh exemplary embodiment, the first lens 710 may have positive refractive power, the first surface of the first lens 710 may be convex, and the second surface of the first lens 710 may be convex.

The second lens 720 may have negative refractive power, the first face of the second lens 720 may be convex, and the second face of the second lens 720 may be concave.

The third lens 730 may have negative refractive power, the first face of the third lens 730 may be convex, and the second face of the third lens 730 may be concave.

The fourth lens 740 may have positive refractive power, the first face of the fourth lens 740 may be concave, and the second face of the fourth lens 740 may be convex.

The fifth lens 750 may have negative refractive power, the first face of the fifth lens 750 may be convex in the paraxial region, and the second face of the fifth lens 750 may be concave in the paraxial region.

In addition, the fifth lens 750 may have at least one inflection point formed on at least one of the first face and the second face. In an example, the first face of the fifth lens 750 may be convex in the paraxial region and concave in a portion or region other than the paraxial region. The second face of the fifth lens 750 may be concave in the paraxial region and convex in a portion or region other than the paraxial region.

Each face of the first lens 710 to the fifth lens 750 may have aspheric coefficients as shown in Table 14 below. In an example, both the object side and the image side of the first lens 710 to the fifth lens 750 may be aspherical.

Table 14

Furthermore, the optical imaging system 700 configured as described above may have the aberration characteristics shown in FIG. 14 .

As described above, according to the optical imaging system of one or more of the above examples, high resolution images can be captured.

Although this disclosure includes specific examples, it will be apparent after understanding the disclosure of this application that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents kind of change. The examples described herein are to be understood in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each example should be considered applicable to similar features or aspects in other examples. If the described techniques are performed in a different order, and/or if components in the described system, architecture, device, or circuit are combined in a different manner and/or replace or supplement with other components or their equivalents, then Appropriate results can still be achieved. Therefore, the scope of the present disclosure is defined not by the specific embodiments but by the claims and their equivalents, and all modifications that come within the scope of the claims and their equivalents should be construed as being included in the present disclosure.

Claims (16)

1. An optical imaging system comprising:

a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in this order from an object side to an image side, wherein:

the optical imaging system further includes an image sensor configured to convert optical signals passing through the first to fifth lenses into electrical signals;

the first lens has a positive refractive power and the second lens has a negative refractive power; and

TTL is more than 10.2mm, and TTL/(2 × IMG HT) is less than or equal to 1.7,

wherein TTL is a distance from an object side surface of the first lens element to an imaging plane on an optical axis, and IMG HT is equal to half a diagonal length of the imaging plane.

2. The optical imaging system of claim 1, wherein:

IMG HT≥4.5mm。

3. the optical imaging system of claim 1, wherein:

1.5<f/IMG HT<3.5，

wherein f is the total focal length of the optical imaging system.

4. The optical imaging system of claim 1, wherein:

n2+n3>3.20，

wherein n2 is a refractive index of the second lens, and n3 is a refractive index of the third lens.

5. The optical imaging system of claim 1, wherein:

|f/f1+f/f2|<1.2，

wherein f is an overall focal length of the optical imaging system, f1 is a focal length of the first lens, and f2 is a focal length of the second lens.

6. The optical imaging system of claim 1, wherein:

BFL/f<0.4,

wherein f is a total focal length of the optical imaging system, and BFL is a distance from an image-side surface of the fifth lens to the imaging surface on the optical axis.

7. The optical imaging system of claim 1, wherein:

0.80≤TTL/f≤1.05，

wherein f is the total focal length of the optical imaging system.

8. The optical imaging system of claim 1, wherein:

0≤D1/f≤0.05，

where f is the total focal length of the optical imaging system, and D1 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.

9. The optical imaging system of claim 1, wherein:

R1/f≤0.35,

where f is the total focal length of the optical imaging system, and R1 is the radius of curvature of the object side surface of the first lens.

10. The optical imaging system of claim 1, wherein:

the third lens has a positive refractive power, the fourth lens has a negative refractive power, and the fifth lens has a negative refractive power.

11. The optical imaging system of claim 1, wherein:

the third lens has a positive refractive power, the fourth lens has a positive refractive power, and the fifth lens has a negative refractive power.

12. The optical imaging system of claim 1, wherein:

the third lens has a negative refractive power, the fourth lens has a positive refractive power, and the fifth lens has a negative refractive power.

13. The optical imaging system of claim 1, further comprising:

a sixth lens disposed between the fifth lens and the imaging surface, wherein:

the third lens has a positive refractive power, the fourth lens has a positive refractive power, the fifth lens has a negative refractive power, and the sixth lens has a negative refractive power.

14. The optical imaging system of claim 1, further comprising:

a sixth lens disposed between the fifth lens and the imaging surface, wherein:

the third lens has a positive refractive power, the fourth lens has a positive refractive power, the fifth lens has a positive refractive power, and the sixth lens has a negative refractive power.

15. The optical imaging system of claim 1, wherein:

at least one of the second lens and the third lens has a refractive index greater than 1.64.

16. The optical imaging system of claim 1, wherein:

an absolute value of a focal length of each of the first lens and the second lens is smaller than an absolute value of a focal length of each of the third lens, the fourth lens, and the fifth lens.

Images