Optical image capturing system

Abstract

The optical image capturing system includes: a first lens having a positive refractive power, a convex object-side surface, and a concave image-side surface; a second lens having 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 refractive power; a sixth lens having refractive power; a seventh lens having refractive power; and an eighth lens having a negative refractive power and a concave image side surface, in which the first to eighth lenses are disposed in order from the object side of the optical image capturing system, and in which the optical image capturing system has a total of eight lenses.

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 an optical imaging system. Background art

[0004] Mobile communication terminals have been provided with camera modules, thereby enabling video calls and image capture. In addition, as the level of the camera function in such mobile communication terminals has gradually increased, there has been an increasing demand for cameras used in mobile communication terminals to have a higher level of resolution and performance.

[0005] However, due to the trend of the gradual miniaturization and lightening of mobile communication terminals, there are limitations in implementing a camera module with high resolution and high performance.

[0006] To solve such problems, recent camera lenses have been formed of plastic (a material lighter than glass), and optical imaging systems have been configured with five or six lenses to achieve a high level of resolution. Summary of the invention

[0007] The present Summary of the Invention section is intended to introduce, in brief form, a selection of inventive concepts, which will be further described in the Detailed Description section below. The present Summary of the Invention section is not intended to identify 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.

[0008] An optical imaging system capable of improving the aberration correction effect and achieving high resolution.

[0009] In one 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, a seventh lens, and an eighth lens sequentially arranged from the object side of the optical imaging system, the first lens having a positive refractive power, the second lens having a positive refractive power, and at least one of the lenses having a negative refractive power and a refractive index greater than 1.68.

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

[0011] Among the first lens to the seventh lens, the refractive index of the lens having a negative refractive power may be greater than the refractive index of the lens having a positive refractive power.

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

[0013] The optical imaging system may satisfy FOV > 70°, where FOV is the field of view angle of the imaging system including the lenses.

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

[0015] The optical imaging system may include a diaphragm disposed between the first lens and the second lens.

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

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

[0018] The third lens may have a negative refractive power.

[0019] The fourth lens may have a positive refractive power.

[0020] The fifth lens may have a negative refractive power.

[0021] The sixth lens may have a positive refractive power.

[0022] The seventh lens may have a positive or negative refractive power, and the eighth lens may have a 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 in sequence from the object side of the optical imaging system. The first lens has a positive refractive power, the second lens has a positive refractive power, at least four of the third lens to the eighth lens have a negative refractive power, and the refractive index of at least one of the lenses having a negative refractive power is greater than 1.68.

[0024] The optical imaging system may satisfy Fno < 1.5, where Fno is the F-number of the imaging system including the lenses.

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

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

[0027] 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, a seventh lens, and an eighth lens sequentially arranged 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 drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0030] Figure 2 is a diagram showing Figure 1 the aberration characteristics of the optical imaging system shown in

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

[0032] Figure 4 is a diagram showing Figure 3 the aberration characteristics of the optical imaging system shown in

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

[0034] Figure 6 is a diagram showing Figure 5 the aberration characteristics of the optical imaging system shown in

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

[0036] Figure 8 is a diagram showing Figure 7 the aberration characteristics of the optical imaging system shown in

[0037] In all of the drawings and the detailed description, the same reference numerals refer to the same elements. For clarity, illustration, and convenience, the drawings may not be drawn to scale, and the relative dimensions, proportions, and depictions of the elements in the drawings may be exaggerated. DETAILED DESCRIPTION

[0038] The following specific embodiments are provided to assist the reader in obtaining a comprehensive understanding of the methods, apparatuses, and / or systems described in this application. However, various changes, modifications, and equivalents of the methods, apparatuses, and / or systems described in this application will be apparent to those of ordinary skill in the art. The order of operations described in this application is merely exemplary, and except for operations that must occur in a specific order, is not limited to the order set forth in this application and can be changed, which will be apparent to those of ordinary skill in the art. Additionally, descriptions of functions and structures known to those of ordinary skill in the art may be omitted for greater clarity and conciseness.

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

[0040] It should be noted that in this application, the use of the phrase "may" with respect to an example or embodiment, e.g., with respect to what an example or embodiment may include or implement, means that there is at least one example or embodiment in which such a feature is included or implemented, and not all examples and embodiments are limited thereto.

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

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

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

[0044] Spatial relative terms such as "above", "upper", "below", and "lower" may be used in this application for convenience of description to describe the relationship of one element relative to another as shown in the drawings. In addition to covering the orientations depicted in the drawings, these spatial relative terms are intended to also cover different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as "above" or "upper" relative to another element will be "below" or "lower" relative to that another element. Thus, depending on the spatial orientation of the device, the term "above" covers both the orientation of "above" and "below". 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 terms used in this application are for the purpose of describing various examples only and are not intended to limit the disclosure. Unless the context clearly indicates otherwise, the articles "a", "an", and "the" are intended to include the plural forms as well. The terms "comprising", "including", and "having" specify the presence of the stated features, numbers, operations, components, elements, and / or combinations thereof, but do not preclude 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 drawings may occur. Accordingly, the examples described in this application are not limited to the specific shapes shown in the drawings, but include shape variations that occur during manufacturing.

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

[0048] In the drawings, for ease of illustration, the thickness, dimensions, and shape of the lens are slightly exaggerated. In particular, the shapes of the spherical surfaces or aspherical surfaces shown in the drawings are merely exemplary. That is, the shapes of the spherical surfaces 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, and the eighth lens refers to the lens closest to the image sensor.

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

[0051] In addition, in the description of the shape of each lens, a surface of the lens being convex means that the paraxial region portion of the corresponding surface is convex, and a surface of the lens being concave means that the paraxial region portion of the corresponding surface is concave. Thus, 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 including the optical axis.

[0053] The optical imaging system according to each example may include eight lenses.

[0054] For example, the 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 in sequence from the object side. The first lens to the eighth lens are respectively spaced apart from each other by a predetermined distance along the optical axis.

[0055] However, the optical imaging system is not limited to including only eight lenses, but may also include other components when necessary.

[0056] For example, the optical imaging system may further 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 further include an infrared filter (hereinafter, "filter") that cuts off infrared rays. The filter may be disposed between the eighth lens and the image sensor.

[0058] The optical imaging system may further include a diaphragm that controls the amount of light.

[0059] In the optical imaging system according to each example, the first lens to the eighth lens may be formed of plastic.

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

[0061] That is, at least one of the first surface and the second surface of all of the first lens to the eighth lens may be aspherical. The aspherical surface of the first lens to the eighth lens may 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, the constants A to I are aspherical coefficients. Further, 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 of the lens.

[0065] The first lens to the eighth lens included 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 lens to the eighth lens may have positive refractive power / positive refractive power / negative refractive power / positive refractive power / negative refractive power / positive refractive power / positive refractive power / negative refractive power.

[0066] The optical imaging system according to each example may 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 expressions, f is the total focal length of the optical imaging system, EPD is the entrance pupil diameter, SD is the distance from the aperture stop to the image side surface of the eighth lens along the optical axis, TD is the distance from the object side surface of the first lens to the image side surface of the eighth lens along the optical axis, FOV is the field of view angle of the optical imaging system, TTL is the distance from the object side surface of the first lens to the image capture surface of the image sensor along the optical axis, and IMG HT is half of the diagonal length of the image capture surface of the image sensor.

[0072] In the conditional expressions, 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 the object side surface bulging. 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 surface and the second surface of the first lens may be aspherical. For example, both surfaces of the first lens may be aspherical.

[0075] The second lens may have a positive refractive power. The second lens may have a meniscus shape with the object side convex. 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 may be aspherical. For example, both surfaces of the second lens may be aspherical.

[0077] The third lens may have a negative refractive power. The third lens may have a meniscus shape with the object side convex. 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 may be aspherical. For example, both surfaces of the third lens may be aspherical.

[0079] The fourth lens may have a positive refractive power. Both surfaces of the fourth lens may be convex in the paraxial region. For example, the first and second surfaces of the fourth lens may be convex 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 be convex in the paraxial region and become concave toward the edge of the first surface of the fourth lens. The second surface of the fourth lens may be convex in the paraxial region and become concave toward the edge of the second surface of the fourth lens.

[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 a negative refractive power. The fifth lens may have a meniscus shape with the object side convex. For example, the first surface of the fifth lens may be convex, and the second surface of the fifth lens 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 be convex in the paraxial region and become concave toward 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 toward 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 may have a positive refractive power. Both surfaces of the sixth lens may be convex. For example, the first and second surfaces of the sixth lens may be convex.

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

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

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

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

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

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

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

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

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

[0096] Among the lenses having a negative refractive power, at least three lenses have a refractive index greater than 1.66.

[0097] Among the lenses with negative refractive power, at least one lens has a refractive index greater than 1.68. For example, the 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 that of other lenses.

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

[0099] That is to say, among the remaining lenses except the eighth lens which is set closest to the image sensor, the refractive index of the lens with negative refractive power can be greater than that of the lens with positive refractive power.

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

[0101] In the optical imaging system configured as described above, multiple lenses can perform an aberration correction function to improve the aberration correction performance.

[0102] Hereinafter, with reference to 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 further include a diaphragm ST, a filter 190, and an image sensor 191.

[0104] The lens characteristics (radius of curvature, thickness of the lens 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 distance along the optical axis from the image side of the eighth lens to the image capture surface of the image sensor, FOV is the field of view angle of the optical imaging system, and IMG HT is half of the diagonal length of the image capture surface of the image sensor.

[0109] In a first example, the first lens 110 may have a 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 a 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 a 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 a positive refractive power, and the first surface and the second surface of the fourth lens 140 are convex in the paraxial region.

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

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

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

[0116] The sixth lens 160 may have a positive refractive power, and the first surface and the second surface of the sixth lens 160 are convex in the paraxial region.

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

[0118] The seventh lens 170 may have a 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 surface and the second surface of the seventh lens 170. For example, the first surface of the seventh lens 170 may be concave in the paraxial region and become convex toward 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 become concave toward the edge of the second surface of the seventh lens 170.

[0120] The eighth lens 180 may have a negative refractive power, and the first surface and the second surface 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 surface and the second surface of the eighth lens 180. For example, the first surface of the eighth lens 180 may be concave in the paraxial region and become convex toward 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 become convex toward 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 an aspherical coefficient as shown in Table 2. For example, all object sides and image sides of the first lens 110 to the eighth lens 180 may be aspherical.

[0123] The aperture stop ST may be disposed 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 may have Figure 2 the aberration characteristics shown in

[0127] Hereinafter, refer to Figure 3 and Figure 4 to 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 further include an aperture stop ST, a filter 290, and an image sensor 291.

[0129] The lens characteristics (radius of curvature, thickness of the lens 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, the Fno is 1.37, the BFL is 0.95 mm, the FOV is 75.6°, and the IMG HT is 4.7 mm.

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

[0134] In the second example, the first lens 210 may have a 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 a 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 a 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 a positive refractive power, and the first surface and the second surface of the fourth lens 240 are convex in the paraxial region.

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

[0139] The fifth lens 250 may have a negative refractive power, and the first surface of the fifth lens 250 may be convex 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 surface and the second surface of the fifth lens 250. For example, the first surface of the fifth lens 250 may be convex in the paraxial region and become concave toward 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 toward the edge of the second surface of the fifth lens 250.

[0141] The sixth lens 260 may have a positive refractive power, and the first surface and the second surface of the sixth lens 260 are convex in the paraxial region.

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

[0143] The seventh lens 270 may have a negative refractive power, and the first surface and the second surface 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 surface and the second surface of the seventh lens 270. For example, the first surface of the seventh lens 270 may be concave in the paraxial region and become convex toward 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 become convex toward the edge of the second surface of the seventh lens 270.

[0145] The eighth lens 280 may have a negative refractive power, and the first surface and the second surface 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 surface and the second surface of the eighth lens 280. For example, the first surface of the eighth lens 280 may be concave in the paraxial region and become convex toward 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 become convex toward 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 an aspherical coefficient as shown in Table 4. For example, all object sides and image sides of the first lens 210 to the eighth lens 280 may be aspherical.

[0148] The aperture stop ST may be disposed 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 of may have Figure 4 the aberration characteristics shown in.

[0152] Hereinafter, referring to 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 further include a diaphragm ST, a filter 390, and an image sensor 391.

[0154] The lens characteristics (radius of curvature, thickness of the lens or distance between lenses, refractive index, and Abbe number) of each lens 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, the Fno is 1.35, the BFL is 0.945 mm, the FOV is 76.4°, and the IMG HT is 4.7 mm.

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

[0159] In the third example, the first lens 310 may have a 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 a 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 a 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 a positive refractive power, and the first and second surfaces of the fourth lens 340 are convex 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 be convex in the paraxial region and become concave toward the edge of the first surface of the fourth lens 340. The second surface of the fourth lens 340 may be convex in the paraxial region and become concave toward the edge of the second surface of the fourth lens 340.

[0164] The fifth lens 350 may have a negative refractive power, and the first surface of the fifth lens 350 may be convex 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 surface and the second surface of the fifth lens 350. For example, the first surface of the fifth lens 350 may be convex in the paraxial region and become concave toward 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 toward the edge of the second surface of the fifth lens 350.

[0166] The sixth lens 360 may have a positive refractive power, and the first surface and the second surface of the sixth lens 360 are convex in the paraxial region.

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

[0168] The seventh lens 370 may have a negative refractive power, and the first surface of the seventh lens 370 may be convex 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 surface and the second surface of the seventh lens 370. For example, the first surface of the seventh lens 370 may be convex in the paraxial region and become concave toward 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 toward the edge of the second surface of the seventh lens 370.

[0170] The eighth lens 380 may have a negative refractive power, and the first surface and the second surface 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 surface and the second surface of the eighth lens 380. For example, the first surface of the eighth lens 380 may be concave in the paraxial region and become convex toward 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 become convex toward 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 an aspherical coefficient as shown in Table 6. For example, all the object sides and image sides of the first lens 310 to the eighth lens 380 may be aspherical.

[0173] The diaphragm ST may be disposed 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 may have Figure 6 the aberration characteristics shown in

[0177] Hereinafter, with reference to Figure 7 and Figure 8 an optical imaging system according to a fourth example will be described.

[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 further include a diaphragm ST, a filter 490, and an image sensor 491.

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

[0180] Table 7

[0181]

[0182]

[0183] According to the fourth example, the total focal length f of the optical imaging system is 6.20 mm, the Fno is 1.29, the BFL is 0.928 mm, the FOV is 73.1°, and the IMG HT is 4.7 mm.

[0184] The definitions of Fno, BFL, FOV, and IMG HT are the same as those in the first example.

[0185] In the fourth example, the first lens 410 may have a 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.

[0186] The second lens 420 may have a 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.

[0187] The third lens 430 may have a 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.

[0188] The fourth lens 440 may have a positive refractive power, and the first surface and the second surface of the fourth lens 440 are convex in the paraxial region.

[0189] At least one inflection point may be formed on at least one of the first surface and the second surface of the fourth lens 440. For example, the first surface of the fourth lens 440 may be convex in the paraxial region and become concave toward the edge of the first surface of the fourth lens 440. The second surface of the fourth lens 440 may be convex in the paraxial region and become concave toward the edge of the second surface of the fourth lens 440.

[0190] The fifth lens 450 may have a negative refractive power, and the first surface of the fifth lens 450 may be convex in the paraxial region and the second surface of the fifth lens 450 may be concave in the paraxial region.

[0191] At least one inflection point may be formed on at least one of the first surface and the second surface 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 toward 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 toward the edge of the second surface of the fifth lens 450.

[0192] The sixth lens 460 may have a positive refractive power, and the first surface and the second surface of the sixth lens 460 are convex in the paraxial region.

[0193] At least one inflection point may be formed on at least one of the first surface and the second surface of the sixth lens 460. For example, the first surface of the sixth lens 460 may be convex in the paraxial region and become concave toward the edge of the first surface of the sixth lens 460.

[0194] The seventh lens 470 may have a negative refractive power, and the first surface of the seventh lens 470 may be convex in the paraxial region and the second surface of the seventh lens 470 may be concave in the paraxial region.

[0195] At least one inflection point may be formed on at least one of the first surface and the second surface of the seventh lens 470. For example, the first surface of the seventh lens 470 may be convex in the paraxial region and become concave toward 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 toward the edge of the second surface of the seventh lens 470.

[0196] The eighth lens 480 may have a negative refractive power, and the first surface and the second surface of the eighth lens 480 are concave in the paraxial region.

[0197] At least one inflection point may be formed on at least one of the first surface and the second surface of the eighth lens 480. For example, the first surface of the eighth lens 480 may be concave in the paraxial region and convex toward 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 toward the edge of the second surface of the eighth lens 480.

[0198] Each surface of the first lens 410 to the eighth lens 480 may have an aspherical coefficient as shown in Table 8. For example, all object sides and image sides of the first lens 410 to the eighth lens 480 may be aspherical.

[0199] The aperture stop ST may be disposed between the first lens 410 and the second lens 420.

[0200] Table 8

[0201] 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

[0202] Figure 7 The optical imaging system may have Figure 8 the aberration characteristics shown in

[0203] According to the example of the optical imaging system described above, the aberration improvement effect can be improved, and at the same time, high resolution can be achieved.

[0204] Although the present disclosure includes specific examples, it will be apparent to those of ordinary skill 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 in this application should be considered only in a descriptive sense and not for purposes of limitation. The description of the features or aspects in each example should be considered applicable to similar features or aspects in other examples. Suitable results can also be obtained if the described techniques are performed in a different order, and / or if the components in the described system, architecture, device, or circuit are combined in a different manner and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of the present 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 the present disclosure.

Claims

1. An optical imaging system, comprising: a first lens having a positive refractive power, a convex object side and a concave image side; a second lens having a refractive power, a convex object side and a concave image side; a third lens having a negative refractive power; a fourth lens having a positive refractive power; a fifth lens having a refractive power; a sixth lens having a refractive power; a seventh lens having a refractive power; and an eighth lens having a negative refractive power and a concave image side, wherein the first lens to the eighth lens are sequentially arranged from the object side of the optical imaging system, and wherein the optical imaging system has a total of eight lenses.

2. The optical imaging system according to claim 1, wherein at least three of the lenses having a negative refractive power have a refractive index greater than 1.

66.

3. The optical imaging system according to claim 1, wherein among the first lens to the seventh lens, at least three of the lenses having a negative refractive power have a refractive index greater than that of the lenses having a positive refractive power.

4. The optical imaging system according to claim 1, wherein (8.00025 / 9.4) ≤ TTL / (2*IMG HT) < 0.9, wherein TTL is the optical axis distance from the object side of the first lens to the image capture surface of the image sensor, and IMGHT is half of the diagonal length of the image capture surface of the image sensor.

5. The optical imaging system according to claim 1, wherein at least one of the lenses having a negative refractive index has a refractive index greater than 1.

68.

6. The optical imaging system according to claim 1, wherein the third lens has a refractive index greater than 1.68, and among the first lens to the eighth lens, the third lens has the largest refractive index.

7. The optical imaging system according to claim 1, wherein 76.4° ≥ FOV > 70°, where FOV is the field of view of the imaging system including the first lens to the eighth lens.

8. The optical imaging system according to claim 1, wherein 1.29 ≤ f / EPD < 1.5, where 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.

9. The optical imaging system according to claim 1, further comprising a diaphragm disposed between the first lens and the second lens.

10. The optical imaging system according to claim 9, wherein (6.2837 / 7.2246) ≥ SD / TD > 0.8, where SD is the optical axis distance from the diaphragm 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.

11. The optical imaging system according to claim 1, wherein the absolute value of the focal length of the seventh lens is the largest among the first lens to the eighth lens.

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

13. The optical imaging system according to claim 1, wherein The third lens has a convex object side and a concave image side.

14. The optical imaging system according to claim 12, wherein, the fourth lens has a convex object side.

15. The optical imaging system according to claim 1, wherein, the fifth lens has a negative refractive power.

16. The optical imaging system according to claim 1, wherein, the fifth lens has a convex object side and a concave image side.

17. The optical imaging system according to claim 1, wherein, the seventh lens has a convex object side and a convex image side.

18. The optical imaging system according to claim 1, wherein, the seventh lens has a positive refractive power.

19. The optical imaging system according to claim 1, wherein, the eighth lens has a concave object side and a concave image side.

Images