Optical imaging system

Abstract

An optical imaging system includes a first lens having positive refractive power, a convex object side surface, and a concave image side surface; a second lens having positive refractive power, a convex object side surface, and a concave image side surface; a third lens having negative refractive power; a fourth lens having positive refractive power; a fifth lens having negative refractive power; a sixth lens having positive refractive power; a seventh lens having refractive power; and an eighth lens having negative refractive power, wherein the first lens through the eighth lens are arranged in order from an object side of the optical imaging system, and wherein at least three of the first lens through the eighth lens have negative refractive power and a refractive index greater than 1.66.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2019-0055680, filed with the Korean Intellectual Property Office on May 13, 2019, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The following description relates to optical imaging systems. Background Technology

[0004] Mobile communication terminals are already equipped with camera modules, enabling video calls and image capture. Furthermore, as the level of camera functionality in these mobile communication terminals gradually increases, there is a growing demand for cameras with higher resolution and performance.

[0005] However, due to the trend of mobile communication terminals becoming smaller and lighter, there are limitations in realizing camera modules with high resolution and high performance.

[0006] To address this problem, recent camera lenses have been made of plastic (a material lighter than glass), and optical imaging systems have been configured with five or six lenses to achieve high levels of resolution. Summary of the Invention

[0007] The summary portion of this invention is intended to provide a brief overview of the chosen inventive concepts, which will be further described in the detailed description portion below. This summary portion is not intended to identify key or essential features of the claimed subject matter, nor to help determine the scope of the claimed subject matter.

[0008] It can improve aberration correction and achieve high-resolution optical imaging systems.

[0009] In one general aspect, the optical imaging system includes: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from the object side of the optical imaging system, wherein the first lens has positive refractive power, the second lens has positive refractive power, and at least one of the lenses has negative refractive power and a refractive index greater than 1.68.

[0010] At least three lenses in the lens may have negative refractive power and a refractive index greater than 1.66.

[0011] Among the first to seventh lenses, the refractive index of a lens with negative refractive power can be greater than that of a lens with positive refractive power.

[0012] The third lens can have negative refractive power and a refractive index greater than 1.68, and among lenses, the refractive index of the third lens can be the largest.

[0013] An optical imaging system can satisfy FOV>70°, where FOV is the field of view of the imaging system including the lens.

[0014] The optical imaging system can satisfy f / EPD<1.5, where f is the total focal length of the imaging system including the lens, and EPD is the entrance pupil diameter.

[0015] An optical imaging system may include an aperture stop disposed between a first lens and a second lens.

[0016] The optical imaging system can satisfy SD / TD>0.8, where SD is the optical axis distance from the aperture stop to the image side of the eighth lens, and TD is the optical axis distance from the object side of the first lens to the image side of the eighth lens.

[0017] The optical imaging system can satisfy TTL / (2×IMG HT)<0.9, where TTL is the optical axis distance from the object side of the first lens to the image capture surface of the image sensor, and IMG HT is half the diagonal length of the image capture surface of the image sensor.

[0018] The third lens can have negative refractive power.

[0019] The fourth lens can have positive refractive power.

[0020] The fifth lens can have negative refractive power.

[0021] The sixth lens can have positive refractive power.

[0022] The seventh lens may have positive or negative refractive power, and the eighth lens may have negative refractive power.

[0023] In another general aspect, the optical imaging system includes: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from the object side of the optical imaging system, wherein the first lens has positive refractive power, the second lens has positive refractive power, at least four of the third to eighth lenses have negative refractive power, and at least one of the lenses having negative refractive power has a refractive index greater than 1.68.

[0024] An optical imaging system can satisfy Fno < 1.5, where Fno is the F-number of the imaging system including the lens.

[0025] Among lenses, the seventh lens has the largest absolute value of focal length.

[0026] Among lenses, the eighth lens has the smallest absolute value of focal length.

[0027] In another general aspect, the optical imaging system includes: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from the object side of the optical imaging system. At least four of the lenses have positive refractive power, and at least three of the lenses have negative refractive power, and Fno < 1.5, where Fno is the F-number of the imaging system including the lenses.

[0028] Other features and aspects will become apparent from the following detailed description, the accompanying drawings, and the appended claims. Attached Figure Description

[0029] Figure 1 This is a diagram illustrating an optical imaging system according to the first example.

[0030] Figure 2 It is shown Figure 1 The diagram shows the aberration characteristics of the optical imaging system.

[0031] Figure 3 This is a diagram illustrating an optical imaging system according to the second example.

[0032] Figure 4 It is shown Figure 3 The diagram shows the aberration characteristics of the optical imaging system.

[0033] Figure 5 This is a diagram illustrating an optical imaging system according to the third example.

[0034] Figure 6 It is shown Figure 5 The diagram shows the aberration characteristics of the optical imaging system.

[0035] Figure 7 This is a diagram illustrating an optical imaging system according to the fourth example.

[0036] Figure 8 It is shown Figure 7 The diagram shows the aberration characteristics of the optical imaging system.

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

[0038] The following detailed embodiments are provided to help readers gain a comprehensive understanding of the methods, apparatus, and / or systems described in this application. However, various changes, modifications, and equivalents to the methods, apparatus, and / or systems described in this application will be readily apparent to those skilled in the art. The order of operations described in this application is merely illustrative, and is not limited to the order set forth herein, except for operations that must occur in a specific order, and can be varied, as will be apparent to those skilled in the art. Furthermore, for clarity and conciseness, descriptions of functions and structures well-known to those skilled in the art may be omitted.

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

[0040] It should be noted that in this application, the use of the word "may" with respect to examples or implementations, for example, with respect to what an example or implementation may include or implement, means that there exists at least one example or implementation that includes or implements such features, and that all examples and implementations are not limited thereto.

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

[0042] As used in this application, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

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

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

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

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

[0047] The features of the examples described in this application can be combined in various ways that will become apparent after understanding the disclosure of this application. Furthermore, although the examples described in this application have multiple configurations, other configurations that will become apparent after understanding the disclosure of this application are also possible.

[0048] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are merely exemplary. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings.

[0049] In this application, the first lens refers to the lens closest to the object, while the eighth lens refers to the lens closest to the image sensor.

[0050] Furthermore, the first surface of each lens refers to the surface (or object-side surface) closest to the object, and the second surface of each lens refers to the surface (or image-side surface) closest to the image. In addition, all values ​​for the radius of curvature, lens thickness, or distance are expressed in millimeters (mm), and the field of view (FOV) is expressed in degrees.

[0051] Furthermore, in the description of the shape of each lens, "a surface of the lens is convex" means that the paraxial region of the corresponding surface is convex, while "a surface of the lens is concave" means that the paraxial region of the corresponding surface is concave. Therefore, even if a surface of the lens is described as convex, the edge portion of the lens may be concave. Similarly, even if a surface of the lens is described as concave, the edge portion of the lens may be convex.

[0052] The paraxial region refers to a very narrow region that includes the optical axis.

[0053] The optical imaging system, according to the various examples, may include eight lenses.

[0054] 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, a seventh lens, and an eighth lens arranged sequentially from the object side. The first lens through the eighth lens are spaced apart from each other by a predetermined distance along the optical axis.

[0055] However, optical imaging systems are not limited to just eight lenses; other components may be included if necessary.

[0056] For example, an optical imaging system may also include an image sensor that converts an image of an object incident on the image sensor into an electrical signal.

[0057] The optical imaging system may also include an infrared filter (hereinafter, "filter") that blocks infrared light. The filter may be positioned between the eighth lens and the image sensor.

[0058] Optical imaging systems may also include apertures for controlling the amount of light.

[0059] In the optical imaging systems according to the various examples, the first through eighth lenses may be formed of plastic.

[0060] At least one of the first to eighth lenses may have an aspherical surface. Furthermore, each of the first to eighth lenses may have at least one aspherical surface.

[0061] In other words, at least one of the first and second surfaces of all lenses from the first to the eighth lens can be aspherical. The aspherical surfaces of the first to the eighth lenses can be represented by the following Equation 1:

[0062] Equation 1

[0063]

[0064] In Equation 1, c is the curvature of the lens (the reciprocal of the radius of curvature), K is the conic constant, and Y is the distance from a point on the aspherical surface of the lens to the optical axis. Additionally, constants A to I are aspherical coefficients. Furthermore, Z is the distance from a point on the aspherical surface of the lens to the tangent plane intersecting the vertex of the aspherical surface.

[0065] The first to eighth lenses in the optical imaging system may sequentially have positive refractive power / positive refractive power / negative refractive power / positive refractive power / negative refractive power / positive refractive power / negative refractive power / negative refractive power from the object side. Alternatively, the first to eighth lenses may have positive refractive power / positive refractive power / negative refractive power / positive refractive power / negative refractive power / positive refractive power / negative refractive power / positive refractive power / negative refractive power.

[0066] The optical imaging systems in each example can satisfy the following conditional expressions:

[0067] Conditional expression 1: f / EPD < 1.5

[0068] Conditional expression 2: SD / TD > 0.8

[0069] Conditional expression 3: FOV > 70°

[0070] Conditional expression 4: TTL / (2×IMG HT)<0.9

[0071] In the conditional expression, f is the total focal length of the optical imaging system, EPD is the entrance pupil diameter, SD is the optical axis distance from the aperture stop to the image side of the eighth lens, TD is the optical axis distance from the object side of the first lens to the image side of the eighth lens, FOV is the field of view of the optical imaging system, TTL is the optical axis distance from the object side of the first lens to the image capture surface of the image sensor, and IMG HT is half the diagonal length of the image capture surface of the image sensor.

[0072] In the conditional expression, f / EPD is the F-number of the optical imaging system.

[0073] The first lens has positive refractive power. The first lens may have a meniscus shape with a convex object side. For example, the first surface of the first lens may be convex, and the second surface of the first lens may be concave.

[0074] At least one of the first and second surfaces of the first lens can be aspherical. For example, both surfaces of the first lens can be aspherical.

[0075] The second lens may have positive refractive power. The second lens may have a meniscus shape with a convex object side. For example, the first surface of the second lens may be convex, and the second surface of the second lens may be concave.

[0076] At least one of the first and second surfaces of the second lens can be aspherical. For example, both surfaces of the second lens can be aspherical.

[0077] The third lens may have negative refractive power. The third lens may have a meniscus shape with a convex object side. For example, the first surface of the third lens may be convex, and the second surface of the third lens may be concave.

[0078] At least one of the first and second surfaces of the third lens can be aspherical. For example, both surfaces of the third lens can be aspherical.

[0079] The fourth lens may have positive refractive power. Both surfaces of the fourth lens may bulge in the paraxial region. For example, the first and second surfaces of the fourth lens may bulge in the paraxial region.

[0080] At least one inflection point may be formed on at least one of the first and second surfaces of the fourth lens. For example, the first surface of the fourth lens may convex in the paraxial region and become concave towards its edge. The second surface of the fourth lens may convex in the paraxial region and become concave towards its edge.

[0081] At least one of the first and second surfaces of the fourth lens may be aspherical. For example, both surfaces of the fourth lens may be aspherical.

[0082] The fifth lens may have negative refractive power. The fifth lens may have a meniscus shape with a convex object side. For example, the first surface of the fifth lens may be convex, and the second surface may be concave.

[0083] At least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens. For example, the first surface of the fifth lens may convex in the paraxial region and become concave towards the edge of the first surface of the fifth lens. The second surface of the fifth lens may be concave in the paraxial region and become convex towards the edge of the second surface of the fifth lens.

[0084] At least one of the first and second surfaces of the fifth lens may be aspherical. For example, both surfaces of the fifth lens may be aspherical.

[0085] The sixth lens can have positive refractive power. Both surfaces of the sixth lens can be convex. For example, the first and second surfaces of the sixth lens can be convex.

[0086] At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens. For example, the first surface of the sixth lens may convex in the paraxial region and become concave towards the edge of the first surface of the sixth lens.

[0087] At least one of the first and second surfaces of the sixth lens may be aspherical. For example, both surfaces of the sixth lens may be aspherical.

[0088] The seventh lens can have positive or negative refractive power. The seventh lens can have a meniscus shape that convexes from the side. For example, the first surface of the seventh lens can be concave in the paraxial region, and the second surface of the seventh lens can be convex in the paraxial region.

[0089] Alternatively, both surfaces of the seventh lens can be concave. For example, the first and second surfaces of the seventh lens can be concave in the paraxial region.

[0090] Alternatively, the seventh lens may have a meniscus shape with a convex object side. For example, the first surface of the seventh lens may convex in the paraxial region, and the second surface of the seventh lens may be concave in the paraxial region.

[0091] At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens. For example, the first surface of the seventh lens may be concave in the paraxial region and convex towards its edge. The second surface of the seventh lens may be convex in the paraxial region and concave towards its edge.

[0092] At least one of the first and second surfaces of the seventh lens can be aspherical. For example, both surfaces of the seventh lens can be aspherical.

[0093] The eighth lens can have negative refractive power. Both surfaces of the eighth lens can be concave. For example, the first and second surfaces of the eighth lens can be concave in the paraxial region.

[0094] At least one inflection point may be formed on at least one of the first and second surfaces of the eighth lens. For example, the first surface of the eighth lens may be concave in the paraxial region and convex towards the edge of the first surface of the eighth lens. The second surface of the eighth lens may be concave in the paraxial region and convex towards the edge of the second surface of the eighth lens.

[0095] At least one of the first and second surfaces of the eighth lens may be aspherical. For example, both surfaces of the eighth lens may be aspherical.

[0096] In a lens with negative refractive power, at least three lenses have a refractive index greater than 1.66.

[0097] In a lens with negative refractive power, at least one lens has a refractive index greater than 1.68. For example, a third lens has negative refractive power, and the refractive index of the third lens is greater than 1.68. The refractive index of the third lens is greater than the refractive index of the other lenses.

[0098] Among the first to seventh lenses, lenses with negative refractive power can be formed to have a refractive index that is greater than that of lenses with positive refractive power.

[0099] In other words, among the lenses other than the eighth lens which is closest to the image sensor, the refractive index of the lens with negative refractive power can be greater than the refractive index of the lens with positive refractive power.

[0100] Among the first to eighth lenses, the seventh lens has the largest absolute value of focal length, and the eighth lens has the smallest absolute value of focal length.

[0101] In the optical imaging system configured as described above, multiple lenses can perform aberration correction functions to enhance aberration improvement performance.

[0102] In the following text, see references Figure 1 and Figure 2 Describe the optical imaging system according to the first example.

[0103] The optical imaging system according to the first example may include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, and an eighth lens 180, and may also include an aperture ST, a filter 190, and an image sensor 191.

[0104] The lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, and Abbe number) of each lens are shown in Table 1.

[0105] Table 1

[0106]

[0107] According to the first example, the total focal length f of the optical imaging system is 6.21 mm, Fno is 1.47, BFL is 0.95 mm, FOV is 74.8°, and IMG HT is 4.7 mm.

[0108] Fno is the F-number of the optical imaging system, BFL is the optical axis distance from the image side of the eighth lens to the image capture surface of the image sensor, FOV is the field of view of the optical imaging system, and IMG HT is half the diagonal length of the image capture surface of the image sensor.

[0109] In the first example, the first lens 110 may have positive refractive power, and the first surface of the first lens 110 may be convex and the second surface of the first lens 110 may be concave.

[0110] The second lens 120 may have positive refractive power, and the first surface of the second lens 120 may be convex and the second surface of the second lens 120 may be concave.

[0111] The third lens 130 may have negative refractive power, and the first surface of the third lens 130 may be convex and the second surface of the third lens 130 may be concave.

[0112] The fourth lens 140 may have positive refractive power, and the first and second surfaces of the fourth lens 140 bulge in the paraxial region.

[0113] At least one inflection point may be formed on at least one of the first and second surfaces of the fourth lens 140. For example, the first surface of the fourth lens 140 may convex in the paraxial region and become concave towards the edge of the first surface of the fourth lens 140. The second surface of the fourth lens 140 may convex in the paraxial region and become concave towards the edge of the second surface of the fourth lens 140.

[0114] The fifth lens 150 may have negative refractive power, and the first surface of the fifth lens 150 may bulge in the paraxial region and the second surface of the fifth lens 150 may be concave in the paraxial region.

[0115] At least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 150. For example, the first surface of the fifth lens 150 may convex in the paraxial region and become concave towards the edge of the first surface of the fifth lens 150. The second surface of the fifth lens 150 may be concave in the paraxial region and become convex towards the edge of the second surface of the fifth lens 150.

[0116] The sixth lens 160 may have positive refractive power, and the first and second surfaces of the sixth lens 160 bulge in the paraxial region.

[0117] At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 160. For example, the first surface of the sixth lens 160 may bulge in the paraxial region and become concave towards the edge of the first surface of the sixth lens 160.

[0118] The seventh lens 170 may have negative refractive power, and the first surface of the seventh lens 170 may be concave in the paraxial region and the second surface of the seventh lens 170 may be convex in the paraxial region.

[0119] At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 170. For example, the first surface of the seventh lens 170 may be concave in the paraxial region and convex towards the edge of the first surface of the seventh lens 170. The second surface of the seventh lens 170 may be convex in the paraxial region and concave towards the edge of the second surface of the seventh lens 170.

[0120] The eighth lens 180 may have negative refractive power, and the first and second surfaces of the eighth lens 180 are concave in the paraxial region.

[0121] At least one inflection point may be formed on at least one of the first and second surfaces of the eighth lens 180. For example, the first surface of the eighth lens 180 may be concave in the paraxial region and convex towards the edge of the first surface of the eighth lens 180. The second surface of the eighth lens 180 may be concave in the paraxial region and convex towards the edge of the second surface of the eighth lens 180.

[0122] Each surface of the first lens 110 to the eighth lens 180 may have aspherical coefficients as shown in Table 2. For example, all object-side and image-side surfaces of the first lens 110 to the eighth lens 180 may be aspherical.

[0123] The aperture ST can be set between the first lens 110 and the second lens 120.

[0124] Table 2

[0125] 1 2 3 4 5 6 7 8 K -0.82879 -26.3981 -0.45843 1.93822 2.62662 -3.21831 6.57E-09 3.89E-09 A 0.00324 0.00738 0.00866 0.00963 -0.01324 -0.01083 -0.01019 -0.01751 B 0.00202 -0.00725 -0.01046 -0.00799 0.00571 0.00964 -0.00154 0.00433 C -0.00266 0.00655 0.0111 0.0062 -0.01464 -0.02374 -0.00021 -0.00897 D 0.00231 -0.00508 -0.01159 -0.00766 0.01858 0.03448 -0.00327 0.00767 E -0.00118 0.00275 0.00795 0.00662 -0.01212 -0.02788 0.0043 -0.00445 F 0.00036 -0.00092 -0.00323 -0.00328 0.00456 0.01364 -0.00261 0.00162 G -6.70E-05 0.00018 0.00075 0.00091 -0.00099 -0.00401 0.00084 -0.00034 H 6.57E-06 -1.91E-05 -9.23E-05 -0.00013 0.00011 0.00066 -0.00013 3.92E-05 I -2.67E-07 8.26E-07 4.68E-06 7.86E-06 -5.47E-06 -4.62E-05 8.38E-06 -1.84E-06 9 10 11 12 13 14 15 16 K -7.31662 -43.3819 -35.9092 -1.2804 7.57E+00 5.20573 -3.51953 -0.97087 A -0.04287 -0.04579 -0.03046 0.03322 0.04203 0.02793 -0.03711 -0.0643 B 0.0121 0.02488 0.02766 -0.01502 -0.02284 -0.0144 -0.0027 0.01305 C -0.00678 -0.01846 -0.01656 0.00422 0.00513 0.00266 0.00278 -0.00211 D 0.00014 0.00905 0.00595 -0.00103 -0.00067 -0.00024 -0.00051 0.00028 E 0.00187 -0.00307 -0.0015 0.00019 4.94E-05 8.33E-06 4.94E-05 -3.04E-05 F -0.00116 0.00072 0.00027 -2.34E-05 -1.42E-06 4.64E-07 -2.81E-06 2.22E-06 G 0.00034 -0.00011 -3.65E-05 1.56E-06 -3.77E-08 -5.70E-08 9.44E-08 -1.02E-07 H -5.01E-05 9.87E-06 2.87E-06 -5.25E-08 3.45E-09 2.19E-09 -1.74E-09 2.64E-09 I 2.89E-06 -3.80E-07 -9.89E-08 6.84E-10 -6.23E-11 -3.12E-11 1.36E-11 -2.91E-11

[0126] Figure 1 The optical imaging system can have Figure 2 The aberration characteristics shown are illustrated.

[0127] In the following text, see references Figure 3 and Figure 4 Describe the optical imaging system according to the second example.

[0128] The optical imaging system according to the second example may include a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, a seventh lens 270, and an eighth lens 280, and may also include an aperture ST, a filter 290, and an image sensor 291.

[0129] The lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, and Abbe number) of each lens are shown in Table 3.

[0130] Table 3

[0131]

[0132] According to the second example, the total focal length f of the optical imaging system is 6.12 mm, Fno is 1.37, BFL is 0.95 mm, FOV is 75.6°, and IMG HT is 4.7 mm.

[0133] The definitions of Fno, BFL, FOV, and IMG HT are the same as in the first example.

[0134] In the second example, the first lens 210 may have positive refractive power, and the first surface of the first lens 210 may be convex and the second surface of the first lens 210 may be concave.

[0135] The second lens 220 may have positive refractive power, and the first surface of the second lens 220 may be convex and the second surface of the second lens 220 may be concave.

[0136] The third lens 230 may have negative refractive power, and the first surface of the third lens 230 may be convex and the second surface of the third lens 230 may be concave.

[0137] The fourth lens 240 may have positive refractive power, and the first and second surfaces of the fourth lens 240 bulge in the paraxial region.

[0138] At least one inflection point may be formed on at least one of the first and second surfaces of the fourth lens 240. For example, the first surface of the fourth lens 240 may convex in the paraxial region and become concave towards the edge of the first surface of the fourth lens 240. The second surface of the fourth lens 240 may convex in the paraxial region and become concave towards the edge of the second surface of the fourth lens 240.

[0139] The fifth lens 250 may have negative refractive power, and the first surface of the fifth lens 250 may bulge in the paraxial region and the second surface of the fifth lens 250 may be concave in the paraxial region.

[0140] At least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 250. For example, the first surface of the fifth lens 250 may convex in the paraxial region and become concave towards the edge of the first surface of the fifth lens 250. The second surface of the fifth lens 250 may be concave in the paraxial region and become convex towards the edge of the second surface of the fifth lens 250.

[0141] The sixth lens 260 may have positive refractive power, and the first and second surfaces of the sixth lens 260 bulge in the paraxial region.

[0142] At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 260. For example, the first surface of the sixth lens 260 may bulge in the paraxial region and become concave towards the edge of the first surface of the sixth lens 260.

[0143] The seventh lens 270 may have negative refractive power, and the first and second surfaces of the seventh lens 270 are concave in the paraxial region.

[0144] At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 270. For example, the first surface of the seventh lens 270 may be concave in the paraxial region and convex towards the edge of the first surface of the seventh lens 270. The second surface of the seventh lens 270 may be concave in the paraxial region and convex towards the edge of the second surface of the seventh lens 270.

[0145] The eighth lens 280 may have negative refractive power, and the first and second surfaces of the eighth lens 280 are concave in the paraxial region.

[0146] At least one inflection point may be formed on at least one of the first and second surfaces of the eighth lens 280. For example, the first surface of the eighth lens 280 may be concave in the paraxial region and convex towards the edge of the first surface of the eighth lens 280. The second surface of the eighth lens 280 may be concave in the paraxial region and convex towards the edge of the second surface of the eighth lens 280.

[0147] Each surface of the first lens 210 to the eighth lens 280 may have aspherical coefficients as shown in Table 4. For example, all object-side and image-side surfaces of the first lens 210 to the eighth lens 280 may be aspherical.

[0148] The aperture ST can be set between the first lens 210 and the second lens 220.

[0149] Table 4

[0150] 1 2 3 4 5 6 7 8 K -0.82675 -26.3981 -0.55179 1.93822 2.62662 -3.1364 0 0 A 0.00344 0.01247 0.01614 0.01575 -0.00812 -0.00707 -0.00989 -0.01892 B 0.00149 -0.0142 -0.0208 -0.01746 -0.00696 -0.0026 -0.00334 0.00718 C -0.00181 0.00833 0.01306 0.01126 0.00039 -0.00323 0.00291 -0.01259 D 0.00147 -0.00274 -0.00641 -0.00703 0.00741 0.01247 -0.00725 0.01052 E -0.00071 0.00052 0.00303 0.00431 -0.0067 -0.01223 0.00725 -0.00599 F 0.00021 -5.03E-05 -0.00117 -0.00198 0.00288 0.0064 -0.00392 0.00217 G -4.06E-05 5.58E-07 0.00029 0.00056 -0.00067 -0.00193 0.00118 -0.00046 H 4.31E-06 3.20E-07 -3.97E-05 -8.56E-05 8.12E-05 3.19E-04 -1.82E-04 5.31E-05 I -2.01E-07 -2.16E-08 2.26E-06 5.41E-06 -3.97E-06 -2.23E-05 1.11E-05 -2.53E-06 9 10 11 12 13 14 15 16 K -7.31662 -43.3819 -35.9092 -1.25885 7.57148 5.20574 -3.51953 -0.94596 A -0.04537 -0.0472 -0.0344 0.03115 0.04587 0.03085 -0.04502 -0.06997 B 0.01603 0.02689 0.03214 -0.01238 -0.02636 -0.01781 0.00058 0.01578 C -0.01145 -0.02078 -0.01895 0.00328 0.0063 0.00399 0.00202 -0.0029 D 0.00459 0.01091 0.00691 -0.00088 -0.00089 -0.00054 -0.0004 0.00043 E -0.0009 -0.00399 -0.00181 0.00019 0.00007 0.00005 0.00004 -0.00005 F -0.00011 0.00099 0.00035 -0.00002 0 0 0 0 G 0.00011 -0.00016 -0.00005 0 0 0 0 0 H -2.25E-05 1.41E-05 3.51E-06 -5.58E-08 3.08E-09 -2.64E-09 -1.18E-09 4.04E-09 I 1.54E-06 -5.37E-07 -1.16E-07 7.53E-10 -6.64E-11 2.51E-11 8.85E-12 -4.43E-11

[0151] Figure 3 The optical imaging system can have Figure 4 The aberration characteristics shown are illustrated.

[0152] In the following text, see references Figure 5 and Figure 6 Describe the optical imaging system according to the third example.

[0153] The optical imaging system according to the third example may include a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, a seventh lens 370 and an eighth lens 380, and may also include an aperture ST, a filter 390 and an image sensor 391.

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

[0155] Table 5

[0156]

[0157] According to the third example, the total focal length f of the optical imaging system is 6.10 mm, Fno is 1.35, BFL is 0.945 mm, FOV is 76.4°, and IMG HT is 4.7 mm.

[0158] The definitions of Fno, BFL, FOV, and IMG HT are the same as in the first example.

[0159] In the third example, the first lens 310 may have positive refractive power, and the first surface of the first lens 310 may be convex and the second surface of the first lens 310 may be concave.

[0160] The second lens 320 may have positive refractive power, and the first surface of the second lens 320 may be convex and the second surface of the second lens 320 may be concave.

[0161] The third lens 330 may have negative refractive power, and the first surface of the third lens 330 may be convex and the second surface of the third lens 330 may be concave.

[0162] The fourth lens 340 may have positive refractive power, and the first and second surfaces of the fourth lens 340 bulge in the paraxial region.

[0163] At least one inflection point may be formed on at least one of the first and second surfaces of the fourth lens 340. For example, the first surface of the fourth lens 340 may convex in the paraxial region and become concave towards the edge of the first surface of the fourth lens 340. The second surface of the fourth lens 340 may convex in the paraxial region and become concave towards the edge of the second surface of the fourth lens 340.

[0164] The fifth lens 350 may have negative refractive power, and the first surface of the fifth lens 350 may bulge in the paraxial region and the second surface of the fifth lens 350 may be concave in the paraxial region.

[0165] At least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 350. For example, the first surface of the fifth lens 350 may convex in the paraxial region and become concave towards the edge of the first surface of the fifth lens 350. The second surface of the fifth lens 350 may be concave in the paraxial region and become convex towards the edge of the second surface of the fifth lens 350.

[0166] The sixth lens 360 may have positive refractive power, and the first and second surfaces of the sixth lens 360 bulge in the paraxial region.

[0167] At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 360. For example, the first surface of the sixth lens 360 may bulge in the paraxial region and become concave towards the edge of the first surface of the sixth lens 360.

[0168] The seventh lens 370 may have negative refractive power, and the first surface of the seventh lens 370 may bulge in the paraxial region and the second surface of the seventh lens 370 may be concave in the paraxial region.

[0169] At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 370. For example, the first surface of the seventh lens 370 may convex in the paraxial region and become concave towards the edge of the first surface of the seventh lens 370. The second surface of the seventh lens 370 may be concave in the paraxial region and become convex towards the edge of the second surface of the seventh lens 370.

[0170] The eighth lens 380 may have negative refractive power, and the first and second surfaces of the eighth lens 380 are concave in the paraxial region.

[0171] At least one inflection point may be formed on at least one of the first and second surfaces of the eighth lens 380. For example, the first surface of the eighth lens 380 may be concave in the paraxial region and convex towards the edge of the first surface of the eighth lens 380. The second surface of the eighth lens 380 may be concave in the paraxial region and convex towards the edge of the second surface of the eighth lens 380.

[0172] Each surface of the first lens 310 to the eighth lens 380 may have aspherical coefficients as shown in Table 6. For example, all object-side and image-side surfaces of the first lens 310 to the eighth lens 380 may be aspherical.

[0173] The aperture ST can be set between the first lens 310 and the second lens 320.

[0174] Table 6

[0175] 1 2 3 4 5 6 7 8 K -0.80275 -26.3981 -0.62277 1.93822 2.62662 -3.07051 0 0 A 0.00323 0.01031 0.01389 0.01832 -0.00463 -0.00562 -0.00789 -0.02293 B 0.00171 -0.00455 -0.00847 -0.01403 -0.00813 -0.00323 -0.01318 0.01966 C -0.00167 -0.00431 -0.00347 0.00075 -0.00626 -0.00607 0.02252 -0.03211 D 0.00131 0.0053 0.00312 0.00128 0.01725 0.01693 -0.02835 0.02766 E -0.00068 -0.00244 0.00037 0.00145 -0.01305 -0.01443 0.02056 -0.01502 F 0.00022 0.00062 -0.00087 -0.00164 0.0051 0.00639 -0.00893 0.00508 G -0.00005 -0.00009 0.0003 0.00061 -0.00111 -0.00156 0.00227 -0.00102 H 5.14E-06 7.52E-06 -4.59E-05 -1.02E-04 1.25E-04 1.99E-04 -3.10E-04 1.12E-04 I -2.53E-07 -2.67E-07 2.64E-06 6.60E-06 -5.82E-06 -1.01E-05 1.73E-05 -5.09E-06 9 10 11 12 13 14 15 16 K -7.31662 -43.3819 -35.9092 -1.23189 7.57E+00 5.20574 -3.51953 -1.0006 A -0.05133 -0.05031 -0.03392 0.02557 0.04016 0.03375 -0.03984 -0.06765 B 0.03093 0.03382 0.03206 -0.00863 -0.02084 -0.01856 -0.00102 0.01484 C -0.03089 -0.0266 -0.01862 0.00268 0.00425 0.00411 0.00221 -0.00261 D 0.02006 0.01384 0.00672 -0.00099 -0.00048 -0.00057 -0.0004 0.00037 E -0.00899 -0.00502 -0.00179 0.00024 0.00002 0.00005 0.00004 -0.00004 F 0.00267 0.00125 0.00035 -0.00003 0 0 0 0 G -0.00048 -0.0002 -0.00005 0 0 0 0 0 H 4.75E-05 1.81E-05 3.73E-06 -8.03E-08 7.07E-09 -4.12E-09 -1.08E-09 2.92E-09 I -1.93E-06 -6.92E-07 -1.24E-07 1.15E-09 -1.08E-10 4.42E-11 7.95E-12 -3.05E-11

[0176] Figure 5 The optical imaging system can have Figure 6 The aberration characteristics shown are illustrated.

[0177] In the following text, see references Figure 7 and Figure 8 Describe the optical imaging system according to the fourth example.

[0178] The optical imaging system according to the fourth example may 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, a seventh lens 470, and an eighth lens 480, and may also include an aperture ST, a filter 490, and an image sensor 491.

[0179] The lens characteristics of each lens (radius of curvature, lens thickness or distance between lenses, refractive index, and Abbe number) are shown in Table 7.

[0180] Table 7

[0181]

[0182] According to the fourth example, the total focal length f of the optical imaging system is 6.20 mm, Fno is 1.29, BFL is 0.928 mm, FOV is 73.1°, and IMG HT is 4.7 mm.

[0183] The definitions of Fno, BFL, FOV, and IMG HT are the same as in the first example.

[0184] In the fourth example, the first lens 410 may have positive refractive power, and the first surface of the first lens 410 may be convex and the second surface of the first lens 410 may be concave.

[0185] The second lens 420 may have positive refractive power, and the first surface of the second lens 420 may be convex and the second surface of the second lens 420 may be concave.

[0186] The third lens 430 may have negative refractive power, and the first surface of the third lens 430 may be convex and the second surface of the third lens 430 may be concave.

[0187] The fourth lens 440 may have positive refractive power, and the first and second surfaces of the fourth lens 440 bulge in the paraxial region.

[0188] At least one inflection point may be formed on at least one of the first and second surfaces of the fourth lens 440. For example, the first surface of the fourth lens 440 may bulge in the paraxial region and become concave towards the edge of the first surface of the fourth lens 440. The second surface of the fourth lens 440 may bulge in the paraxial region and become concave towards the edge of the second surface of the fourth lens 440.

[0189] The fifth lens 450 may have negative refractive power, and the first surface of the fifth lens 450 may bulge in the paraxial region and the second surface of the fifth lens 450 may be concave in the paraxial region.

[0190] At least one inflection point may be formed on at least one of the first and second surfaces of the fifth lens 450. For example, the first surface of the fifth lens 450 may be convex in the paraxial region and become concave towards the edge of the first surface of the fifth lens 450. The second surface of the fifth lens 450 may be concave in the paraxial region and become convex towards the edge of the second surface of the fifth lens 450.

[0191] The sixth lens 460 may have positive refractive power, and the first and second surfaces of the sixth lens 460 bulge in the paraxial region.

[0192] At least one inflection point may be formed on at least one of the first and second surfaces of the sixth lens 460. For example, the first surface of the sixth lens 460 may bulge in the paraxial region and become concave towards the edge of the first surface of the sixth lens 460.

[0193] The seventh lens 470 may have negative refractive power, and the first surface of the seventh lens 470 may bulge in the paraxial region and the second surface of the seventh lens 470 may be concave in the paraxial region.

[0194] At least one inflection point may be formed on at least one of the first and second surfaces of the seventh lens 470. For example, the first surface of the seventh lens 470 may convex in the paraxial region and become concave towards the edge of the first surface of the seventh lens 470. The second surface of the seventh lens 470 may be concave in the paraxial region and become convex towards the edge of the second surface of the seventh lens 470.

[0195] The eighth lens 480 may have negative refractive power, and the first and second surfaces of the eighth lens 480 are concave in the paraxial region.

[0196] At least one inflection point may be formed on at least one of the first and second surfaces of the eighth lens 480. For example, the first surface of the eighth lens 480 may be concave in the paraxial region and convex towards the edge of the first surface of the eighth lens 480. The second surface of the eighth lens 480 may be concave in the paraxial region and convex towards the edge of the second surface of the eighth lens 480.

[0197] Each surface of the first lens 410 to the eighth lens 480 may have aspherical coefficients as shown in Table 8. For example, all object-side and image-side surfaces of the first lens 410 to the eighth lens 480 may be aspherical.

[0198] The aperture ST can be set between the first lens 410 and the second lens 420.

[0199] Table 8

[0200] 1 2 3 4 5 6 7 8 K -0.80532 -26.3981 -0.62707 1.93822 2.62662 -3.06613 0 0 A 0.0028 0.00909 0.0109 0.01445 -0.00534 -0.00339 -0.00695 -0.02016 B 0.00157 -0.00368 -0.00139 -0.0035 -0.00282 -0.01006 -0.01 0.01573 C -0.00146 -0.0032 -0.01158 -0.01351 -0.00991 0.00992 0.01513 -0.0235 D 0.00102 0.00361 0.0101 0.01435 0.01591 -0.00362 -0.01791 0.01861 E -0.00046 -0.00152 -0.00399 -0.00679 -0.01013 0.00048 0.01222 -0.00935 F 0.00013 0.00036 0.00088 0.00176 0.00349 0.00003 -0.00497 0.00293 G -0.00002 -0.00005 -0.00011 -0.00025 -0.00068 0.00001 0.00118 -0.00055 H 2.38E-06 3.71E-06 7.79E-06 1.80E-05 6.97E-05 -9.12E-06 -1.49E-04 5.51E-05 I -1.05E-07 -1.22E-07 -2.32E-07 -4.54E-07 -2.94E-06 1.16E-06 7.71E-06 -2.32E-06 9 10 11 12 13 14 15 16 K -7.31662 -43.3819 -35.9092 -1.21289 7.57E+00 5.20574 -3.51953 -0.97443 A -0.04572 -0.04334 -0.02972 0.02201 0.0354 0.02975 -0.03529 -0.05931 B 0.02572 0.02495 0.02547 -0.00635 -0.01697 -0.01509 -0.00114 0.0118 C -0.02413 -0.01738 -0.01339 0.00165 0.0032 0.00308 0.00179 -0.00188 D 0.015 0.00813 0.00437 -0.00058 -0.00034 -0.0004 -0.0003 0.00024 E -0.00646 -0.00272 -0.00106 0.00013 0.00002 0.00004 0.00003 -0.00002 F 0.00183 0.00064 0.00019 -0.00002 0 0 0 0 G -0.00031 -0.0001 -0.00002 0 0 0 0 0 H 2.92E-05 8.24E-06 1.77E-06 -3.62E-08 3.54E-09 -2.16E-09 -5.91E-10 1.30E-09 I -1.12E-06 -2.96E-07 -5.42E-08 4.73E-10 -4.99E-11 2.15E-11 4.04E-12 -1.24E-11

[0201] Figure 7 The optical imaging system can have Figure 8 The aberration characteristics shown are illustrated.

[0202] Based on the examples of optical imaging systems described above, aberration correction can be improved while achieving high resolution.

[0203] While this disclosure includes specific examples, it will be apparent to those skilled in the art that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein should be considered descriptive only and not for limiting purposes. Descriptions of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Suitable results may also be obtained if the described techniques are performed in a different order, and / or if components in the described system, architecture, device, or circuit are combined in different ways and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of this disclosure should not be limited by the specific embodiments but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included in this disclosure.

Claims

1. An optical imaging system, comprising: The first lens has positive refractive power, a convex object-side surface, and a concave image-side surface; The second lens has positive refractive power, a convex object side, and a concave image side; The third lens has negative refractive power, a convex object side, and a concave image side; The fourth lens has positive refractive power, a convex object-side surface, and a convex image-side surface; The fifth lens has negative refractive power, a convex object-side surface, and a concave image-side surface; The sixth lens has positive refractive power, a convex object-side surface, and a convex image-side surface; The seventh lens has negative refractive power; as well as The eighth lens has negative refractive power, a concave object-side surface, and a concave image-side surface. The first lens to the eighth lens are sequentially arranged from the object side of the optical imaging system. Among them, at least three of the first to eighth lenses have negative refractive power and a refractive index greater than 1.

66. The total number of lenses with refractive power is 8, and Among them, 8.00025 / (2 4.7) ≤ TTL / (2 IMG HT) < 0.9, where TTL is the optical axis distance from the object side of the first lens to the image capture surface of the image sensor, and IMG HT is half the diagonal length of the image capture surface of the image sensor.

2. The optical imaging system according to claim 1, wherein, In the first to the seventh lens, the refractive index of the at least three lenses with negative refractive power is greater than that of the lens with positive refractive power.

3. The optical imaging system according to claim 1, wherein, At least one of the lenses with negative refractive power has a refractive index greater than 1.

68.

4. The optical imaging system according to claim 3, wherein, The third lens has a refractive index greater than 1.68, and Among the first to the eighth lenses, the third lens has the highest refractive index.

5. The optical imaging system according to claim 1, wherein, FOV > 70°, where FOV is the field of view of the imaging system including the first lens to the eighth lens.

6. The optical imaging system according to claim 1, wherein f / EPD < 1.5, wherein, f is the total focal length of the imaging system including the first lens to the eighth lens, and EPD is the entrance pupil diameter.

7. The optical imaging system according to claim 1 further includes an aperture stop disposed between the first lens and the second lens.

8. The optical imaging system according to claim 7, wherein, SD / TD > 0.8, where SD is the optical axis distance from the aperture stop to the image side of the eighth lens, and TD is the optical axis distance from the object side of the first lens to the image side of the eighth lens.

9. The optical imaging system according to claim 1, wherein, Among the first to the eighth lenses, the seventh lens has the largest absolute value of focal length.

10. The optical imaging system according to claim 1, wherein, Among the first to the eighth lenses, the absolute value of the focal length of the eighth lens is the smallest.

Images