Optical imaging system

Abstract

An optical imaging system includes a total of seven lenses having refractive powers, the lenses including: a first lens having a positive refractive power; a second lens having a negative refractive power; a third lens having a positive refractive power; a fourth lens having a negative refractive power; a fifth lens having a positive refractive power; a sixth lens having a positive refractive power; and a seventh lens having a negative refractive power, wherein the first lens to the seventh lens are sequentially arranged from an object side, and wherein a focal length of the third lens is 18.0 mm or more.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10 - 2018 - 0076470, filed with the Korean Intellectual Property Office on July 2, 2018, the entire disclosure of which is incorporated herein by reference for all purposes. Technical field

[0003] The following description relates to an optical imaging system including seven lenses. Background art

[0004] Generally, small - sized cameras are mounted on wireless terminal devices. For example, small - sized cameras are typically mounted on the front and rear of wireless terminal devices. Such small - sized cameras are used for imaging outdoor landscapes, indoor people, etc., and thus, small - sized cameras need to have performance similar to that of ordinary cameras. However, due to the size of the wireless terminal device, the installation space for the small - sized camera in the wireless terminal device is limited, and thus, it may be difficult to achieve high performance. Therefore, there is a need to develop an optical imaging system that can improve the performance of a small - sized camera without increasing the size of the camera. Summary of the invention

[0005] The Summary of the Invention section is intended to introduce, in a brief form, a selection of inventive concepts, and these inventive concepts will be further described in the Detailed Description section below. The Summary of the Invention section is not intended to identify the key features or essential features of the claimed subject matter, nor is it intended to assist in determining the scope of the claimed subject matter.

[0006] In one general aspect, an optical imaging system includes: a first lens having a positive refractive power and a convex object side; a second lens having a negative refractive power; a third lens having a refractive power; a fourth lens having a refractive power; a fifth lens having a refractive power; a sixth lens having a positive refractive power and a convex image side; and a seventh lens having a negative refractive power and a concave image side. The first lens to the seventh lens may be sequentially arranged from the object side. In the optical imaging system, 1 < f / f6 and V2 < 40, where f is the focal length of the optical imaging system, f6 is the focal length of the sixth lens, and V2 is the Abbe number of the second lens.

[0007] The F No. of the optical imaging system may be 1.8 or less.

[0008] The optical imaging system may satisfy 0.05 < OAL / HFOV < 0.3, where OAL is the value of the distance from the object side of the first lens to the imaging surface expressed in mm, and HFOV is the value of the half - field angle of the optical imaging system expressed in °.

[0009] The optical imaging system can satisfy 0.2 < Th7 / Th6 < 0.9, where Th6 is a thickness of the sixth lens at an optical center, and Th7 is a thickness of the seventh lens at the optical center.

[0010] The fourth lens can have a negative refractive power.

[0011] The optical imaging system can include a stop disposed between the first lens and the second lens.

[0012] The fifth lens can include an inflection point on one or both of an object side surface and an image side surface of the fifth lens.

[0013] The sixth lens can include an inflection point on one or both of an object side surface and an image side surface of the sixth lens.

[0014] The seventh lens can include an inflection point on one or both of an object side surface and an image side surface of the seventh lens.

[0015] In another general aspect, an optical imaging system includes, in order from an object side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. In the optical imaging system, F No. < 1.8 and V2 < 40, where V2 is an Abbe number of the second lens.

[0016] The third lens can have a positive refractive power.

[0017] The fourth lens can have a negative refractive power.

[0018] The fifth lens can have a positive refractive power.

[0019] The third lens can include a convex object side surface.

[0020] The fourth lens can include a concave object side surface.

[0021] The fifth, sixth, and seventh lenses can each include an inflection point on one or both of a respective object side surface and a respective image side surface.

[0022] In another general aspect, an optical imaging system includes, in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. In the optical imaging system, the fourth lens includes one convex surface and one concave surface, and F No. < 1.8.

[0023] The fourth lens can include a concave object side surface and a convex image side surface.

[0024] The fourth lens can include a convex object side surface and a concave image side surface.

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

[0026] Figure 1 is a diagram illustrating a first example of an optical imaging system.

[0027] Figure 2 is shown Figure 1 aberration curves of the optical imaging system shown in

[0028] Figure 3 is a diagram illustrating a second example of an optical imaging system.

[0029] Figure 4 is shown Figure 3 aberration curves of the optical imaging system shown in

[0030] Figure 5 is a diagram illustrating a third example of an optical imaging system.

[0031] Figure 6 is shown Figure 5 aberration curves of the optical imaging system shown in

[0032] Figure 7 is a diagram illustrating a fourth example of an optical imaging system.

[0033] Figure 8 is shown Figure 7 aberration curves of the optical imaging system shown in

[0034] Throughout the drawings and detailed description, identical reference characters refer to identical elements. The drawings can not be to scale and the relative dimensions, proportions and depiction of elements in the drawings can be exaggerated for purpose of clarity, illustration and convenience. DETAILED DESCRIPTION

[0035] The following detailed description is provided to help the reader understand the methods, devices and / or systems described in this application. However, various changes, modifications and equivalents can become apparent to those skilled in the art after understanding the disclosure provided in this application. For example, the order of operations described in this application can be merely examples, and is not limited to the order described in this application, except where such order is specifically required, and can be changed without departing from the scope of the application, after understanding the disclosure provided in this application. Also, descriptions of features that are well known can be omitted for the sake of clarity and brevity.

[0036] The features described in this application can be implemented in different forms and should not be construed as limited to the examples described in this application. Rather, these examples are provided as illustrative of a number of ways to implement the methods, devices and / or systems described in this application, in one embodiment. Indeed, after understanding the disclosure provided herein, those skilled in the art will appreciate that many modifications are possible and will recognize various applications that should be treated as equivalents to the examples described herein.

[0037] In this application, the use of the term "may" in relation to examples or embodiments, for example, the content that an example or embodiment can include or implement, means that there is at least one example or embodiment in which the feature is included or implemented, but all examples and embodiments are not limited to this.

[0038] Throughout the specification, when an element such as a layer, region or substrate is referred to as being "on", "connected to" or "coupled to" another element, it can be directly on, directly connected to, or directly coupled to the other element, or one or more other elements can be interposed therebetween. Conversely, when an element is referred to as being "directly on", "directly connected to" or "directly coupled to" another element, there are no other elements interposed therebetween.

[0039] As used in this application, the term "and / or" includes any one of the associated listed items, as well as any combination of any two or more of the associated listed items.

[0040] Although the terms such as "first", "second" and "third" can be used in this application to describe various components, parts, regions, layers or portions, these components, parts, regions, layers or portions are not limited by the terms. Rather, these terms are used only to distinguish one component, part, region, layer or portion from another component, part, region, layer or portion. Therefore, the first component, first part, first region, first layer or first portion mentioned in the example can also be called the second component, second part, second region, second layer or second portion without departing from the teachings of the example described in this application.

[0041] Spatially relative terms can be used herein for ease of description to describe one element's relationship to another element as illustrated in the figures. Such spatially relative terms include "above," "up," "below," and "down," and can encompass different orientations depending on the spatial orientation of the device. For example, if the device is turned over, then an element described as above or up relative to another element would now be below or down relative to that other element. Thus, the term "above" encompasses both a first orientation where a first element is above a second element and a second orientation where the first element is below the second element. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0042] The terminology used in the present application is for the purpose of describing various examples only and is not intended to be limiting of the present disclosure. The use of the singular herein includes the plural unless the context clearly dictates otherwise. The use of the term "a" or "an" herein does not exclude a plurality, and "comprising" means "including but not limited to" and "consisting of" means "including and limited to."

[0043] Variations can occur in the shapes of the elements illustrated in the drawings due to differences in manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the particular shapes of elements as illustrated in the drawings, but include deviations in shapes that occur due to manufacturing techniques and / or tolerances.

[0044] Features of the examples described herein can be combined with each other in a manner that will be apparent after studying this disclosure. Additionally, other configurations of the examples described herein are possible that are not yet realized at this time but are anticipated to be possible after studying this disclosure.

[0045] Hereinafter, examples will be described with reference to the accompanying drawings.

[0046] In examples, the first lens can refer to a lens disposed closest to an object (or subject), and the seventh lens can refer to a lens disposed closest to an imaging surface (or image sensor). In examples, a radius of curvature, a thickness, an OAL (a distance from an object side surface of the first lens to the imaging surface), an ImgH (1 / 2 of a diagonal length of the imaging surface), and a focal length of the lens are all expressed in millimeters (mm).

[0047] The thickness of the lenses, the spacing between the lenses, and the OAL can be the distance at the optical axis of the lenses. In the description of the lens shape, a face of a lens being convex indicates that the paraxial region of the face is convex, and a face of a lens being concave indicates that the paraxial region of the face is concave. Thus, in a configuration where a face of a lens is described as convex, the edge region of the lens can be concave. In a similar manner, in a configuration where a face of a lens is described as concave, the edge region of the lens can be convex.

[0048] The optical imaging system can include seven lenses. For example, the optical imaging system can include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens to the seventh lens can be disposed with a certain spacing. For example, the image side face and the object side face of adjacent lenses can not contact each other.

[0049] The first lens can have a refractive power. For example, the first lens can have a positive refractive power. The first lens can have a convex face. For example, the first lens can have a convex object side face.

[0050] The first lens can include an aspherical surface. For example, both faces of the first lens can be aspherical. The first lens can be made of a material having high light transmittance and excellent machinability. For example, the first lens can be made of a plastic material. The first lens can have a relatively low refractive index. For example, the refractive index of the first lens can be less than 1.6.

[0051] The second lens can have a refractive power. For example, the second lens can have a negative refractive power. The second lens can have a convex face. For example, the second lens can have a convex object side face.

[0052] The second lens can include an aspherical surface. For example, the object side face of the second lens can be aspherical. The second lens can be made of a material having high light transmittance and excellent machinability. For example, the second lens can be made of a plastic material. The second lens can have a refractive index higher than that of the first lens. For example, the refractive index of the second lens can be 1.65 or more.

[0053] The third lens can have a refractive power. For example, the third lens can have a positive refractive power or a negative refractive power. The third lens can have a convex face. For example, the third lens can have a convex object side face.

[0054] The third lens can include an aspherical surface. For example, the image side face of the third lens can be aspherical. The third lens can be made of a material having high light transmittance and excellent machinability. For example, the third lens can be made of a plastic material. The third lens can have a refractive index approximately similar to that of the first lens. For example, the refractive index of the third lens can be less than 1.6.

[0055] The fourth lens can have a refractive power. For example, the fourth lens can have a negative refractive power. The fourth lens can have a concave surface. For example, the object side surface or the image side surface of the fourth lens can be concave.

[0056] The fourth lens can include aspheric surfaces. For example, both surfaces of the fourth lens can be aspheric. The fourth lens can be made of a material having high light transmittance and excellent processability. For example, the fourth lens can be made of a plastic material. The fourth lens can have a refractive index higher than that of the first lens. For example, the refractive index of the fourth lens can be 1.6 or more.

[0057] The fifth lens can have a refractive power. For example, the fifth lens can have a positive refractive power or a negative refractive power. The fifth lens can have a convex surface. For example, the object side surface of the fifth lens can be convex. The fifth lens can have a shape having a point of inflection. For example, the point of inflection can be formed on at least one of the object side surface and the image side surface of the fifth lens.

[0058] The fifth lens can include aspheric surfaces. For example, both surfaces of the fifth lens can be aspheric. The fifth lens can be made of a material having high light transmittance and excellent processability. For example, the fifth lens can be made of a plastic material. The fifth lens can have a refractive index approximately similar to that of the fourth lens. For example, the refractive index of the fifth lens can be 1.6 or more.

[0059] The sixth lens can have a refractive power. For example, the sixth lens can have a positive refractive power. The sixth lens can have at least one convex surface. For example, the object side surface or the image side surface of the sixth lens can be convex, or both surfaces of the sixth lens can be convex. The sixth lens can have a shape having a point of inflection. For example, the point of inflection can be formed on at least one of the object side surface and the image side surface of the sixth lens.

[0060] The sixth lens can include aspheric surfaces. For example, both surfaces of the sixth lens can be aspheric. The sixth lens can be made of a material having high light transmittance and excellent processability. For example, the sixth lens can be made of a plastic material. The sixth lens can have a refractive index lower than that of the fifth lens. For example, the refractive index of the sixth lens can be less than 1.6.

[0061] The seventh lens can have a refractive power. For example, the seventh lens can have a negative refractive power. The seventh lens can have at least one concave surface. For example, the object side surface or the image side surface of the seventh lens can be concave, or both surfaces of the seventh lens can be concave. The seventh lens can have a shape having a point of inflection. For example, the point of inflection can be formed on at least one of the object side surface and the image side surface of the seventh lens.

[0062] The seventh lens can include an aspheric surface. For example, both surfaces of the seventh lens can be aspheric. The seventh lens can be made of a material having high light transmittance and excellent processability. For example, the seventh lens can be made of a plastic material. The seventh lens can have a refractive index approximately similar to that of the sixth lens. For example, the seventh lens can have a refractive index less than 1.6.

[0063] The aspheric surfaces of the first to seventh lenses can be represented by Equation 1 below.

[0064] Equation 1

[0065]

[0066] In Equation 1, "c" is the reciprocal of the radius of curvature of each lens, "K" is a conic constant, "r" is the distance from a certain point on the aspheric surface of the lens to the optical axis, "A" to "J" are aspheric constants, and "Z" (or SAG) is the height in the direction of the optical axis from a certain point on the aspheric surface of the lens to the vertex of the aspheric surface.

[0067] The optical imaging system can further include a filter, an image sensor, and a stop.

[0068] The filter can be disposed between the seventh lens and the image sensor. The filter can block light having a specific wavelength. For example, the filter can block light having an infrared wavelength.

[0069] The image sensor can form an imaging surface. For example, the surface of the image sensor can form the imaging surface.

[0070] The stop can be disposed to adjust the amount of light incident to the image sensor. For example, the stop can be disposed between the first lens and the second lens, or between the second lens and the third lens.

[0071] The optical imaging system can satisfy the following conditional expression:

[0072]

[0073] In the conditional expression, "f" is the focal length of the optical imaging system, "f6" is the focal length of the sixth lens, "V2" is the Abbe number of the second lens, "OAL" is the value of the distance from the object side surface of the first lens to the imaging surface in mm, "HFOV" is the value of the half field of view of the optical imaging system in °, "Th6" is the thickness of the sixth lens at the optical center, and "Th7" is the thickness of the seventh lens at the optical center.

[0074] In the following description, the optical imaging system will be described according to an example.

[0075] Reference will be made to Figure 1A first example of an optical imaging system is described.

[0076] The optical imaging system 100 can 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, and a seventh lens 170.

[0077] The first lens 110 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 120 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 130 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 140 can have a negative refractive power, and can have a concave object side surface and a convex image side surface. The fifth lens 150 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 150 can have a shape forming an inflection point on the object side surface and the image side surface of the fifth lens 150. The sixth lens 160 can have a positive refractive power, and can have a convex object side surface and a convex image side surface. The sixth lens 160 can have a shape forming an inflection point on the object side surface and the image side surface of the sixth lens 160. The seventh lens 170 can have a negative refractive power, and can have a concave object side surface and a concave image side surface. The seventh lens 170 can have a shape forming an inflection point on the object side surface and the image side surface of the seventh lens 170.

[0078] The optical imaging system 100 can further include a filter 180, an image sensor 190, and a stop ST. The filter 180 can be disposed between the seventh lens 170 and the image sensor 190, and the stop ST can be disposed between the first lens 110 and the second lens 120.

[0079] The optical imaging system 100 can include a plurality of lenses having a relatively high refractive index. For example, the second lens 120, the fourth lens 140, and the fifth lens 150 can have a refractive index of 1.6 or more.

[0080] The optical imaging system 100 can have an aberration characteristic as shown in Figure 2 Table 1 lists the characteristics of the lenses of the optical imaging system 100. In Figure 1 In the optical imaging system 100 of

[0081] Table 1

[0082]

[0083] A second example of an optical imaging system will be described with reference to Figure 3

[0084] ​The optical imaging system 200 can 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, and a seventh lens 270.

[0085] The first lens 210 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 220 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 230 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 240 can have a negative refractive power, and can have a concave object side surface and a convex image side surface. The fifth lens 250 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 250 can have a shape forming an inflection point on the object side surface and the image side surface of the fifth lens 250. The sixth lens 260 can have a positive refractive power, and can have a convex object side surface and a convex image side surface. The sixth lens 260 can have a shape forming an inflection point on the object side surface and the image side surface of the sixth lens 260. The seventh lens 270 can have a negative refractive power, and can have a concave object side surface and a concave image side surface. The seventh lens 270 can have a shape forming an inflection point on the object side surface and the image side surface of the seventh lens 270.

[0086] The optical imaging system 200 can further include a filter 280, an image sensor 290, and a stop ST (not shown). The filter 280 can be disposed between the seventh lens 270 and the image sensor 290, and the stop ST can be disposed between the first lens 210 and the second lens 220.

[0087] The optical imaging system 200 can include a plurality of lenses having a relatively high refractive index. For example, the second lens 220, the fourth lens 240, and the fifth lens 250 can have a refractive index of 1.6 or more.

[0088] The optical imaging system 200 can have an aberration characteristic as shown in Table 2. Figure 4 The optical imaging system 200 has a focal length of 4.220 mm, and a total field angle of 78.5°. Figure 3 The optical imaging system 200 has a focal length of 4.220 mm, and a total field angle of 78.5°.

[0089] Table 2

[0090]

[0091]

[0092] A third example of an optical imaging system will be described with reference to Figure 5

[0093] ​The optical imaging system 300 can 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, and a seventh lens 370.

[0094] The first lens 310 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 320 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 330 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 340 can have a negative refractive power, and can have a concave object side surface and a convex image side surface. The fifth lens 350 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 350 can have a shape forming an inflection point on the object side surface and the image side surface of the fifth lens 350. The sixth lens 360 can have a positive refractive power, and can have a convex object side surface and a convex image side surface. The sixth lens 360 can have a shape forming an inflection point on the object side surface and the image side surface of the sixth lens 360. The seventh lens 370 can have a negative refractive power, and can have a concave object side surface and a concave image side surface. The seventh lens 370 can have a shape forming an inflection point on the object side surface and the image side surface of the seventh lens 370.

[0095] The optical imaging system 300 can further include a filter 380, an image sensor 390, and a stop ST (not shown). The filter 380 can be disposed between the seventh lens 370 and the image sensor 390, and the stop ST can be disposed between the first lens 310 and the second lens 320.

[0096] The optical imaging system 300 can include a plurality of lenses having a relatively high refractive index. For example, the second lens 320, the fourth lens 340, and the fifth lens 350 can have a refractive index of 1.6 or more.

[0097] The optical imaging system 300 can have an aberration characteristic as shown in FIG. 3B. Figure 6 Table 3 lists the characteristics of the lenses of the optical imaging system 300. In the optical imaging system 300 of Table 3, the focal length is 4.230 mm, and the total field angle is 78.1°. Figure 5

[0098] Table 3

[0099]

[0100]

[0101] A fourth example of an optical imaging system will be described with reference to FIG. 3B. Figure 7

[0102] ​​The optical imaging system 400 can include a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, and a seventh lens 470.

[0103] The first lens 410 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 420 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 430 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 440 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 450 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 450 can have a shape forming an inflection point on the object side surface and the image side surface of the fifth lens 450. The sixth lens 460 can have a positive refractive power, and can have a convex object side surface and a convex image side surface. The sixth lens 460 can have a shape forming an inflection point on the object side surface and the image side surface of the sixth lens 460. The seventh lens 470 can have a negative refractive power, and can have a concave object side surface and a concave image side surface. The seventh lens 470 can have a shape forming an inflection point on the object side surface and the image side surface of the seventh lens 470.

[0104] The optical imaging system 400 can further include a filter 480, an image sensor 490, and a stop ST (not shown). The filter 480 can be disposed between the seventh lens 470 and the image sensor 490, and the stop ST can be disposed between the first lens 410 and the second lens 420.

[0105] The optical imaging system 400 can include a plurality of lenses having a relatively high refractive index. For example, the second lens 420, the fourth lens 440, and the fifth lens 450 can have a refractive index of 1.6 or more.

[0106] The optical imaging system 400 can have an aberration characteristic as shown in Table 4. Figure 8 In the optical imaging system 400 of Table 4, the focal length is 4.30 mm, and the total field angle is 77.5°. Figure 7 In the optical imaging system 400 of Table 4, the focal length is 4.30 mm, and the total field angle is 77.5°.

[0107] Table 4

[0108]

[0109] Table 5 lists values of conditional expressions of the optical imaging systems of the first example to the fourth example.

[0110] Table 5

[0111] Conditional expression First example Second example Third example Fourth example f / f6 1.797 1.733 1.721 1.415 V2 19.25 19.25 19.25 19.25 F No. 1.580 1.580 1.580 1.580 OAL / HFOV 0.133 0.134 0.134 0.134 Th7 / Th6 0.567 0.525 0.489 0.625

[0112] The optical imaging system of each example can have optical properties as described below. For example, the focal length of the optical imaging system can be in a range of 4.0 mm to 4.5 mm, the overall length OAL can be in a range of 5.0 mm to 5.5 mm, the total field of view angle (FOV) can be in a range of 70° to 80°, the focal length of the first lens can be in a range of 4.0 mm to 5.0 mm, the focal length of the second lens can be in a range of -20 mm to -10 mm, the focal length of the third lens can be 18 mm or more, the focal length of the fourth lens can be -8 mm or less, the focal length of the fifth lens can be 50 mm or more, the focal length of the sixth lens can be in a range of 2.0 mm to 4.0 mm, and the focal length of the seventh lens can be in a range of -3.0 mm to -1.5 mm.

[0113] According to the foregoing examples, the optical imaging system can improve the performance of a small size camera.

[0114] While the present disclosure includes specific examples, it will be apparent to those skilled in the art, after understanding the disclosure provided herein, that various changes in form and details can be made without departing from the spirit and scope of the claims and their equivalents. The examples described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each example should be considered as being applicable to similar features or aspects in other examples. Suitable results can be achieved if the described techniques are performed in a different order, and / or if components in the described systems, architectures, devices, or circuits are combined in a different manner, and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure should be determined by the appended claims and their equivalents, rather than by the described examples, which are provided for only the purpose of illustration and not for limitation.

Claims

1. An optical imaging system comprising a total of seven lenses having refractive power, said lenses comprising: The first lens has positive refractive power and a convex object-side surface; The second lens has negative refractive power; The third lens has positive refractive power; The fourth lens has negative refractive power; The fifth lens has positive refractive power; The sixth lens has positive refractive power; as well as The seventh lens has negative refractive power and a concave image-side surface. The first lens to the seventh lens are arranged sequentially from the object side. Wherein, the focal length of the third lens is greater than 18.0 mm and less than or equal to 754.84395 mm, and Wherein, 1.415 ≤ f / f6 ≤ 1.797, where f is the focal length of the optical imaging system and f6 is the focal length of the sixth lens.

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

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

4. The optical imaging system according to claim 1, wherein, The fifth lens includes an inflection point on one or both of the object-side and image-side surfaces of the sixth lens.

5. The optical imaging system according to claim 1, wherein, F No. is 1.8 or smaller.

6. The optical imaging system according to claim 1, wherein, 0.05 < OAL / HFOV < 0.3, where OAL is the distance in mm from the object side of the first lens to the imaging plane, and HFOV is the half field of view of the optical imaging system in °.

7. The optical imaging system according to claim 1, wherein, 0.2 < Th7 / Th6 ≤ 0.567, where Th6 is the thickness of the sixth lens at the optical center and Th7 is the thickness of the seventh lens at the optical center.

8. The optical imaging system according to claim 1, wherein, The focal length of the optical imaging system is in the range of 4.0 mm to 4.5 mm.

9. The optical imaging system according to claim 1, wherein, The distance from the object side of the first lens to the imaging plane is in the range of 5.0 mm to 5.5 mm.

10. The optical imaging system according to claim 1, wherein, The focal length of the first lens is in the range of 4.0mm to 5.0mm.

11. The optical imaging system according to claim 1, wherein, The focal length of the second lens is in the range of -20.0mm to -10.0mm.

12. The optical imaging system according to claim 1, wherein, The first lens has a concave image-side surface, the second lens has a convex object-side surface and a concave image-side surface, the third lens has a convex object-side surface and a concave image-side surface, the fifth lens has a convex object-side surface and a concave image-side surface, the sixth lens has a convex object-side surface and a convex image-side surface, and the seventh lens has a concave object-side surface.

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