Optical imaging system

Abstract

The present invention provides an optical imaging system comprising: a first lens having an image-side surface recessed along an optical axis; a second lens having an image-side surface recessed along the optical axis; a third lens having positive refractive power, an object-side surface convex along the optical axis, and an image-side surface recessed along the optical axis; a fourth lens having positive refractive power and an object-side surface recessed along the optical axis; a fifth lens; a sixth lens having positive refractive power; and a seventh lens having an object-side surface convex along the optical axis, wherein the first lens to the seventh lens are arranged sequentially from the object side toward the imaging plane, and the optical imaging system comprises a total of seven lenses having refractive power.

Description

[0001] This application is a divisional application of the invention patent application "Optical Imaging System" filed on May 17, 2017, with application number 201710347797.6. Technical Field

[0002] The following description relates to an optical imaging system comprising seven lenses. Background Technology

[0003] As the resolution of small cameras continues to increase, the pixels included in the image sensor have become smaller. For example, the pixel size of the image sensor in a camera with a resolution of 13 megapixels or greater can be smaller than the pixel size of the image sensor in an 8-megapixel camera. Because this phenomenon involves a reduction in the amount of light incident on each pixel of the image sensor, it can be difficult to obtain a clear and bright image. Therefore, optical imaging systems are being developed to improve both resolution and brightness. Summary of the Invention

[0004] This summary is provided to introduce, in a simplified form, the selected concepts that will be further described in the detailed embodiments below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0005] In one general aspect, an optical imaging system includes: a first lens having a concave image-side surface; a second lens having a concave image-side surface; and a third lens having positive refractive power. The optical imaging system further includes: a fourth lens having positive refractive power and a concave object-side surface; a fifth lens; a sixth lens having positive refractive power; and a seventh lens having a convex object-side surface. The first to seventh lenses are arranged sequentially at intervals from the object side toward the imaging plane.

[0006] The first lens of the optical imaging system may have an object-side surface that convexes along the optical axis. The second lens of the optical imaging system may have an object-side surface that convexes along the optical axis. The third lens of the optical imaging system may have an object-side surface that convexes along the optical axis and an image-side surface that is recessed along the optical axis.

[0007] The fifth lens of the optical imaging system may have an object-side surface recessed along the optical axis and an image-side surface convex along the optical axis. The sixth lens of the optical imaging system may have an object-side surface convex along the optical axis and an image-side surface recessed along the optical axis. The seventh lens of the optical imaging system may have an image-side surface recessed along the optical axis.

[0008] In another general aspect, an optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially arranged from the object side toward the imaging surface. The optical imaging system satisfies the conditional expression f2 / f < -2.0, where f represents the total focal length of the optical imaging system and f2 is the focal length of the second lens.

[0009] The optical imaging system may satisfy the conditional expression 0 < f1 / f < 2.0, where f represents the total focal length of the optical imaging system and f1 represents the focal length of the first lens. The optical imaging system may satisfy three conditional expressions 25 < V1 - V2 < 45, V1 - V3 < 25, and 25 < V1 - V5 < 45, where V1 represents the Abbe number of the first lens, V2 represents the Abbe number of the second lens, V3 represents the Abbe number of the third lens, and V5 represents the Abbe number of the fifth lens.

[0010] The optical imaging system may satisfy the conditional expression 1.5 < f3 / f, where f represents the total focal length of the optical imaging system and f3 represents the focal length of the third lens. The optical imaging system may also satisfy the conditional expression 3.0 < |f4 / f|, where f represents the total focal length of the optical imaging system and f4 represents the focal length of the fourth lens. The optical imaging system may include a concave image-side surface on the first lens and the sixth lens and a concave object-side surface of the fourth lens.

[0011] In another general aspect, an optical imaging system includes: a first lens having a positive refractive power; a second lens having a negative refractive power; and a third lens. The optical imaging system further includes: a fourth lens having an image-side surface convex along the optical axis; a fifth lens having a negative refractive power; a sixth lens; and a seventh lens having a negative refractive power.

[0012] The optical imaging system may satisfy the conditional expression -1.3 < f1 / f2, where f1 represents the focal length of the first lens and f2 represents the focal length of the second lens. The optical imaging system may satisfy the conditional expression f5 / f < 0, where f represents the total focal length of the optical imaging system and f5 represents the focal length of the fifth lens. The optical imaging system may satisfy the conditional expression f7 / f < 0, where f represents the total focal length of the optical imaging system and f7 represents the focal length of the seventh lens.

[0013] Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. Description of the Drawings

[0014] Figure 1 is a diagram of an optical imaging system according to a first example.

[0015] Figure 2 It is shown Figure 1 The diagram shows a set of aberration curves for the optical imaging system.

[0016] Figure 3 It is a list Figure 1 The table shows the aspherical characteristics of the optical imaging system.

[0017] Figure 4 This is a diagram of the optical imaging system based on the second example.

[0018] Figure 5 It is shown Figure 4 The diagram shows a set of aberration curves for the optical imaging system.

[0019] Figure 6 It is a list Figure 4 The table shows the aspherical characteristics of the optical imaging system.

[0020] Figure 7 This is a diagram of the optical imaging system based on the third example.

[0021] Figure 8 It is shown Figure 7 The diagram shows a set of aberration curves for the optical imaging system.

[0022] Figure 9 It is a list Figure 7 The table shows the aspherical characteristics of the optical imaging system.

[0023] Throughout the accompanying drawings and detailed embodiments, the same reference numerals denote the same elements where applicable. The drawings may not be to scale, and for clarity, illustration, and convenience, the relative dimensions, scale, and depiction of elements in the drawings may be exaggerated. Detailed Implementation

[0024] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various modifications, alterations, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, descriptions of well-known functions and constructions may be omitted for clarity and brevity.

[0025] The features described herein may be implemented in various forms and are not to be construed as being limited to the examples described herein. Rather, the examples described herein are provided merely to illustrate some of the many feasible ways in which the methods, devices, and / or systems described herein will be apparent upon understanding the disclosure of this application.

[0026] Although terms such as “first,” “second,” and “third” may be used herein to describe the various components, regions, or parts, these components, regions, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, region, or part from another. Therefore, without departing from the teachings of the examples discussed herein, what is referred to as the first component, region, or part may also be referred to as the second component, region, or part.

[0027] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the presence of the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0028] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0029] The features of the examples described herein can be combined in various ways that will become apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have various configurations, it will be apparent upon understanding the disclosure of this application that other configurations are also possible.

[0030] The example provides an optical imaging system with high brightness and high resolution for installation in a small terminal. The example is further described in detail below with reference to the accompanying drawings.

[0031] According to the example, the first lens refers to the lens closest to the object or subject from which the image is captured. The seventh lens is the lens closest to the imaging plane or image sensor. In the embodiment, the radius of curvature, thickness, optical axis distance (OAL) from the object-side surface of the first lens to the imaging plane, half the diagonal length of the imaging plane (IMG HT), and focal length of each lens are expressed in millimeters (mm). Those skilled in the art will appreciate that other units of measurement may be used. Furthermore, in the embodiment, the optical axis distance (SL) between the aperture and the image sensor, the image height (IMG HT), the back focal length (BFL) of the lens, the total focal length of the optical system, and the focal length of each lens are expressed in millimeters (mm). Additionally, the lens thickness, the spacing between lenses, OAL, and SL are distances measured based on the optical axis of the lens.

[0032] A convex lens surface means that the optical axis portion of the corresponding surface protrudes, and a concave lens surface means that the optical axis portion of the corresponding surface is recessed. Therefore, in a lens configuration where one surface is described as convex, the edge portion of said surface may be recessed. Similarly, in a lens configuration where one surface is described as concave, the edge portion of said surface may protrude. In other words, the paraxial region of the lens may convex, while the remaining portion outside the paraxial region may convex, concave, or flat. Furthermore, in embodiments, the lens thickness and radius of curvature are measured relative to the optical axis of the respective lens.

[0033] Based on the illustrative example, the embodiment of the optical system described includes seven lenses with refractive powers. However, the number of lenses in the optical system can be varied in order to achieve the various results and effects described below; for example, it can be varied between two and seven lenses. Furthermore, although each lens is described as having a specific refractive power, at least one of the lenses can employ a different refractive power to achieve the desired result.

[0034] An optical imaging system includes seven lenses. For example, an optical imaging system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially from the object side.

[0035] The first lens has refractive power. For example, the first lens has positive refractive power. One surface of the first lens is concave. In an embodiment, the image-side surface of the first lens may be concave.

[0036] The first lens may have aspherical surfaces. For example, both surfaces of the first lens are aspherical. The first lens is formed of a material with high light transmittance and excellent processability. In an example, the first lens is formed of a plastic material. However, the material of the first lens is not limited to plastic. In another example, the first lens may be formed of a glass material. The first lens may have a low refractive index. In an embodiment, the refractive index of the first lens is less than 1.6.

[0037] The second lens has refractive power. For example, the second lens has negative refractive power. One surface of the second lens is concave. In an embodiment, the image-side surface of the second lens is concave.

[0038] The second lens has an aspherical surface. For example, the object-side surface of the second lens is aspherical. The second lens is formed of a material with high light transmittance and excellent processability. In an example, the second lens is formed of a plastic material. However, the material of the second lens is not limited to plastic. In another example, the second lens may be formed of a glass material. The second lens may have a refractive index higher than that of the first lens. In an embodiment, the refractive index of the second lens is 1.65 or higher.

[0039] The third lens has refractive power. For example, the third lens has positive refractive power. The third lens has an aspherical surface. For example, the image-side surface of the third lens is an aspherical surface.

[0040] The third lens is formed of a material with high light transmittance and excellent processability. For example, the third lens is formed of a plastic material. However, the material of the third lens is not limited to plastic. In another example, the third lens may be formed of a glass material. The third lens has a refractive index substantially similar to that of the first lens. In an embodiment, the refractive index of the third lens is less than 1.6.

[0041] The fourth lens has refractive power. For example, the fourth lens has positive refractive power. One surface of the fourth lens is concave. In this embodiment, the object-side surface of the fourth lens is concave.

[0042] The fourth lens has aspherical surfaces. For example, both surfaces of the fourth lens are aspherical. The fourth lens is formed of a material with high light transmittance and excellent machinability. In this example, the fourth lens is formed of a plastic material. However, the material of the fourth lens is not limited to plastic. In another example, the fourth lens may be formed of a glass material. The fourth lens has a refractive index that is substantially the same as that of the third lens. For example, the refractive index of the fourth lens is less than 1.6.

[0043] The fifth lens has refractive power. For example, the fifth lens has negative refractive power. The fifth lens has aspherical surfaces. For example, both surfaces of the fifth lens are aspherical.

[0044] The fifth lens is formed of a material with high light transmittance and excellent machinability. In this example, the fifth lens is formed of a plastic material. However, the material of the fifth lens is not limited to plastic. In another example, the fifth lens may be formed of a glass material. The fifth lens has a refractive index higher than that of the first lens. For example, the refractive index of the fifth lens is 1.6 or higher.

[0045] The sixth lens has refractive power. For example, the sixth lens has positive refractive power. The sixth lens has inflection points. In an embodiment, both surfaces of the sixth lens have one or more inflection points.

[0046] The sixth lens has aspherical surfaces. As an example, both surfaces of the sixth lens are aspherical. The sixth lens is formed of a material with high light transmittance and excellent machinability. In this example, the sixth lens is formed of a plastic material. However, the material of the sixth lens is not limited to plastic. In another example, the sixth lens may be formed of a glass material. The sixth lens has a refractive index substantially similar to that of the fifth lens. For example, the refractive index of the sixth lens is 1.6 or higher.

[0047] The seventh lens has refractive power. For example, the seventh lens has negative refractive power. One surface of the seventh lens is convex. In an embodiment, the object-side surface of the seventh lens is convex. The seventh lens has inflection points. For example, both surfaces of the seventh lens have one or more inflection points.

[0048] The seventh lens has aspherical surfaces. For example, both surfaces of the seventh lens are aspherical. The seventh lens is formed of a material with high light transmittance and excellent machinability. In this example, the seventh lens is formed of a plastic material. However, the material of the seventh lens is not limited to plastic. In another example, the seventh lens may be formed of a glass material. The seventh lens has a refractive index lower than that of the sixth lens. For example, the refractive index of the seventh lens is less than 1.6.

[0049] The aspherical surfaces of the first to seventh lenses can be represented by Equation 1.

[0050] Equation 1

[0051]

[0052] In Equation 1, c represents the reciprocal of the radius of curvature of the lens, k represents the conic section constant, r represents the distance from a point on the aspherical surface of the lens to the optical axis, A to H and J represent the aspherical coefficients, and Z (or SAG) represents the distance between a point on the aspherical surface of the lens at a distance r and the tangent plane, wherein the tangent plane intersects the vertex of the aspherical surface of the lens.

[0053] An optical imaging system also includes filters, an image sensor, and an aperture. A filter can be positioned between the seventh lens and the image sensor. Filters block certain wavelengths of light to obtain a clear image. For example, a filter blocks infrared wavelengths of light.

[0054] An image sensor forms an imaging surface. For example, the surface of the image sensor forms the imaging surface. An aperture is configured to adjust the amount of light incident on the lens. In this example, the aperture may be positioned between the second and third lenses or between the third and fourth lenses.

[0055] An optical imaging system satisfies any one or any combination of two or more of the following conditional expressions:

[0056] [Conditional expression 1] 0 <f1 / f<2.0

[0057] [Conditional Expression 2] 25 <V1-V2<45

[0058] [Conditional Expression 3] V1-V3<25

[0059] [Conditional Expression 4] 25 <V1-V5<45

[0060] [Conditional expression 5] f2 / f<-2.0

[0061] [Conditional Expression 6] 1.5 <f3 / f

[0062] [Conditional expression 7] 3.0 < |f4 / f|

[0063] [Conditional Expression 8] f5 / f<0

[0064] [Conditional expression 9] 0 <f6 / f

[0065] [Conditional Expression 10]f7 / f<0

[0066] [Conditional Expression 11] OAL / f<1.4

[0067] [Conditional Expression 12]-1.3 <f1 / f2

[0068] [Conditional Expression 13]-2.0 <f2 / f3<0

[0069] [Conditional Expression 14] BFL / f < 0.4

[0070] [Conditional Expression 15] D2 / f < 0.1

[0071] [Conditional Expression 16] 80° <FOV

[0072] [Conditional Expression 17] F-number ≤ 2.05

[0073] In the conditional expression, f represents the total focal length of the optical imaging system, f1 represents the focal length of the first lens, f2 represents the focal length of the second lens, f3 represents the focal length of the third lens, f4 represents the focal length of the fourth lens, f5 represents the focal length of the fifth lens, f6 represents the focal length of the sixth lens, f7 represents the focal length of the seventh lens, V1 represents the Abbe number of the first lens, V2 represents the Abbe number of the second lens, V3 represents the Abbe number of the third lens, and V5 represents the Abbe number of the fifth lens. Furthermore, OAL represents the distance along the optical axis from the object surface of the first lens to the image plane, BFL represents the distance along the optical axis from the image surface of the seventh lens to the image plane, and D2 represents the distance along the optical axis from the image surface of the first lens to the object surface of the second lens.

[0074] Conditional expression 1 is a relational expression used to limit the refractive index of the first lens. When the first lens is outside the numerical range of conditional expression 1, the refractive power distribution of different lenses will be limited.

[0075] Conditional expressions 2 through 4 are relational expressions used to improve chromatic aberration in optical imaging systems. For example, outside the numerical range of conditional expressions 2 through 4, the improvement in chromatic aberration in optical imaging systems will be limited.

[0076] Conditional expressions 5 to 7 are relational expressions used to improve aberration correction in optical imaging systems. For example, aberration correction in optical imaging systems outside the numerical range of conditional expressions 5 to 7 is limited because the refractive power of the second to fourth lenses is either quite high or quite low.

[0077] Conditional expressions 8 to 10 are relational expressions used to limit the refractive power of an optical imaging system. For example, outside the numerical range of conditional expressions 8 to 10, maintaining the desired refractive power of the fifth to seventh lenses will be limited.

[0078] Conditional expressions 11 and 14 are relational expressions used for miniaturization of optical imaging systems. For example, in optical imaging systems outside the numerical range of conditional expressions 11 and 14, the distance from the first lens to the imaging plane is quite long. Therefore, the optical imaging system cannot be sufficiently miniaturized.

[0079] Conditional expressions 12 and 13 are relational expressions used to improve the aberration characteristics of an optical imaging system. For example, in an optical imaging system outside the numerical range of conditional expressions 12 and 13, the refractive power of a particular lens among the first to third lenses is quite large. Therefore, this will degrade the aberration characteristics. Conditional expression 15 is also a relational expression used to improve the aberration characteristics of an optical imaging system. For example, outside the upper limit of conditional expression 15, the improvement of longitudinal chromatic aberration in the optical imaging system is limited.

[0080] An optical imaging system that satisfies the above conditions can produce a bright image. For example, the optical imaging system may have an F-number of 2.05 or less. Furthermore, the optical imaging system may achieve a resolution of 13 megapixels or greater and may have a wide viewing angle of 80 degrees or greater.

[0081] Next, optical imaging systems based on several examples will be described. First, reference will be made to... Figure 1 An optical imaging system according to a first example is described. The optical imaging system 100 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens 170.

[0082] The first lens 110 has positive refractive power. The object-side surface of the first lens 110 is convex, and the image-side surface is concave. The second lens 120 has negative refractive power. The object-side surface of the second lens 120 is convex, and the image-side surface is concave. The third lens 130 has positive refractive power. The object-side surface of the third lens 130 is convex, and the image-side surface is concave. The fourth lens 140 has positive refractive power. The object-side surface of the fourth lens 140 is concave, and the image-side surface is convex.

[0083] The fifth lens 150 has negative refractive power. The object-side surface of the fifth lens 150 is concave, and the image-side surface is convex. The sixth lens 160 has positive refractive power. The object-side surface of the sixth lens 160 is convex, and the image-side surface is concave. Furthermore, the sixth lens 160 has inflection points formed on both of its surfaces. The seventh lens 170 has negative refractive power. The object-side surface of the seventh lens 170 is convex, and the image-side surface is concave. Furthermore, the seventh lens 170 has inflection points formed on both of its surfaces.

[0084] The optical imaging system 100 also includes a filter 180, an image sensor 190, and an aperture stop. The filter 180 may be disposed between the seventh lens 170 and the image sensor 190. The aperture stop may be disposed between the second lens 120 and the third lens 130 or between the third lens 130 and the fourth lens 140.

[0085] The optical imaging system constructed as described above exhibits the following characteristics: Figure 2 The curves shown in the figure illustrate the aberration characteristics. Figure 3 The aspherical characteristics of the optical imaging system according to the first example are listed. The lens characteristics of the optical imaging system according to the first example are described in Table 1.

[0086] Table 1

[0087]

[0088]

[0089] Reference Figure 4 An optical imaging system according to a second example is described. The optical imaging system 200 includes a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, and a seventh lens 270.

[0090] The first lens 210 has positive refractive power. The object surface of the first lens 210 is convex, and the image surface is concave. The second lens 220 has negative refractive power. The object surface of the second lens 220 is convex, and the image surface is concave. The third lens 230 has positive refractive power. The object surface of the third lens 230 is convex, and the image surface is concave. The fourth lens 240 has positive refractive power. The object surface of the fourth lens 240 is concave, and the image surface is convex.

[0091] The fifth lens 250 has negative refractive power. The object-side surface of the fifth lens 250 is concave, and the image-side surface is convex. The sixth lens 260 has positive refractive power. The object-side surface of the sixth lens 260 is convex, and the image-side surface is concave. Furthermore, the sixth lens 260 has inflection points formed on both of its surfaces. The seventh lens 270 has negative refractive power. The object-side surface of the seventh lens 270 is convex, and the image-side surface is concave. Furthermore, the seventh lens 270 has inflection points formed on both of its surfaces.

[0092] The optical imaging system 200 also includes a filter 280, an image sensor 290, and an aperture stop. The filter 280 may be disposed between the seventh lens 270 and the image sensor 290. The aperture stop may be disposed between the second lens 220 and the third lens 230 or between the third lens 230 and the fourth lens 240.

[0093] The optical imaging system constructed as described above exhibits the following characteristics: Figure 5 The curves shown in the figure illustrate the aberration characteristics. Figure 6 The aspherical characteristics of the optical imaging system according to the second example are listed. The lens characteristics of the optical imaging system according to the second example are described in Table 2.

[0094] Table 2

[0095]

[0096]

[0097] Reference Figure 7 The optical imaging system according to the third example is described. The optical imaging system 300 includes a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, and a seventh lens 370.

[0098] The first lens 310 has positive refractive power. The object-side surface of the first lens 310 is convex, and the image-side surface is concave. The second lens 320 has negative refractive power. The object-side surface of the second lens 320 is convex, and the image-side surface is concave. The third lens 330 has positive refractive power. The object-side surface of the third lens 330 is convex, and the image-side surface is concave. The fourth lens 340 has positive refractive power. The object-side surface of the fourth lens 340 is concave, and the image-side surface is convex.

[0099] The fifth lens 350 has negative refractive power. The object-side surface of the fifth lens 350 is concave, and the image-side surface is convex. The sixth lens 360 has positive refractive power. The object-side surface of the sixth lens 360 is convex, and the image-side surface is concave. Furthermore, the sixth lens 360 has inflection points formed on both of its surfaces. The seventh lens 370 has negative refractive power. The object-side surface of the seventh lens 370 is convex, and the image-side surface is concave. Furthermore, the seventh lens 370 has inflection points formed on both of its surfaces.

[0100] The optical imaging system 300 also includes a filter 380, an image sensor 390, and an aperture stop. The filter 380 may be disposed between the seventh lens 370 and the image sensor 390. The aperture stop may be disposed between the second lens 320 and the third lens 330 or between the third lens 330 and the fourth lens 340.

[0101] The optical imaging system constructed as described above exhibits the following characteristics: Figure 8 The curves shown in the figure illustrate the aberration characteristics. Figure 9 The aspherical characteristics of the optical imaging system according to the third example are listed. The lens characteristics of the optical imaging system according to the third example are described in Table 3.

[0102] Table 3

[0103]

[0104] Table 4 shows the value of the conditional expression for the optical imaging system according to the first to third examples.

[0105] Table 4

[0106]

[0107] As described above, according to the examples, an optical imaging system capable of long-distance imaging when installed in a small terminal can be realized. While this disclosure includes specific examples, it will be apparent upon understanding the disclosure of this application that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be understood as descriptive in nature only and not for limiting purposes. The description of features or aspects in each example is to be understood as applicable to similar features or aspects in other examples. Suitable results may be obtained if the described techniques are performed in a different order, and / or if components in the described system, architecture, apparatus, or circuit are combined in different ways and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of this disclosure is not limited by the specific embodiments but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be understood as being included in this disclosure.

Claims

1. An optical imaging system, characterized in that, The optical imaging system includes: A first lens, having a positive refractive power, an object-side surface that bulges along the optical axis, and an image-side surface that recesses along the optical axis; A second lens, having a negative refractive power and an image-side surface that recesses along the optical axis; A third lens, having a positive refractive power, an object-side surface that bulges along the optical axis, and an image-side surface that recesses along the optical axis; A fourth lens, having a positive refractive power and an object-side surface that recesses along the optical axis; A fifth lens, having a negative refractive power; A sixth lens, having a positive refractive power; and A seventh lens, having a negative refractive power, an object-side surface that bulges along the optical axis, and an image-side surface that recesses along the optical axis, wherein, the first lens to the seventh lens are sequentially arranged from the object side toward the imaging surface, wherein, the optical imaging system has a total of seven lenses with refractive power, wherein, the optical imaging system satisfies the following conditional expressions: 3.0 < |f4 / f| < 24.597, and f2 / f < -2.0, wherein, f is the total focal length of the optical imaging system, f2 is the focal length of the second lens, and f4 is the focal length of the fourth lens.

2. The optical imaging system according to claim 1, characterized in that, The F number is less than 2.

05.

3. The optical imaging system according to claim 1, characterized in that, The FOV is greater than 80°.

4. The optical imaging system according to claim 1, characterized in that, 0 < f1 / f < 2.0, wherein, f1 is the focal length of the first lens.

5. The optical imaging system according to claim 1, characterized in that, -2 < f2 / f3 < -0.616, wherein, f3 is the focal length of the third lens.

6. The optical imaging system according to claim 1, characterized in that, 1.5 < f3 / f, wherein, f3 is the focal length of the third lens.

7. The optical imaging system according to claim 1, characterized in that, The image-side surface of the sixth lens recesses along the optical axis.

8. The optical imaging system according to claim 1, characterized in that, The refractive index of the sixth lens is 1.6 or greater.

9. An optical imaging system, characterized in that, The optical imaging system includes: A first lens, having a positive refractive power, an object-side surface that bulges along the optical axis, and an image-side surface that recesses along the optical axis; A second lens, having a negative refractive power and an image-side surface that recesses along the optical axis; A third lens, having a positive refractive power and an image-side surface that recesses along the optical axis; A fourth lens, having a positive refractive power and an object-side surface that recesses along the optical axis; A fifth lens, having a negative refractive power; A sixth lens, having a positive refractive power; and A seventh lens, having a negative refractive power, an object-side surface that bulges along the optical axis, and an image-side surface that recesses along the optical axis, wherein, the first lens to the seventh lens are sequentially arranged from the object side toward the imaging surface, wherein, the optical imaging system has a total of seven lenses with refractive power, wherein, the refractive index of the sixth lens is 1.6 or greater, wherein, the optical imaging system satisfies the following conditional expressions: 3.0 < |f4 / f| < 24.597, and f2 / f < -2.0, wherein, f is the total focal length of the optical imaging system, f2 is the focal length of the second lens, and f4 is the focal length of the fourth lens.

10. The optical imaging system according to claim 9, characterized in that, The F number is less than 2.

05.

11. The optical imaging system according to claim 9, characterized in that, The FOV is greater than 80°.

12. The optical imaging system according to claim 9, characterized in that, The FOV is greater than 80°.

13. The optical imaging system according to claim 9, characterized in that, -2 < f2 / f3 < -0.61, wherein, f3 is the focal length of the third lens.

14. The optical imaging system according to claim 9, characterized in that, 1.5 < f3 / f, wherein, f3 is the focal length of the third lens.

15. The optical imaging system according to claim 9, characterized in that, The image-side surface of the sixth lens is recessed along the optical axis.

Images