Optical imaging system

Abstract

An optical imaging system includes, in order from an object side of the optical imaging system, 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, and a refractive index of at least one of the first lens through the eighth lens is 1.67 or more.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2018-0172452, filed with the Korean Intellectual Property Office on December 28, 2018, and Korean Patent Application No. 10-2019-0055679, 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 already include camera modules for video calls and image capture. Furthermore, as the functionality of cameras in these mobile communication terminals increases, there is a growing demand for cameras with higher resolution and performance.

[0005] However, the trend towards miniaturization and lightweighting of mobile communication terminals presents limitations in realizing camera modules with high resolution and performance.

[0006] To address these issues, recent camera lenses have been made of plastic (a material lighter than glass), and optical imaging systems have been constructed using 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, and at least one of the lenses has a refractive index of 1.67 or greater.

[0010] The optical imaging system can satisfy FOV>70°, where FOV is the field of view of the imaging system including the first to eighth lenses.

[0011] The optical imaging system can satisfy f / EPD < 1.9, where f is a total focal length of the imaging system including the first lens through the eighth lens, and EPD is an entrance pupil diameter of the imaging system.

[0012] The first lens can have a positive refractive power, the second lens can have a positive refractive power, and the third lens can have a positive refractive power.

[0013] The fourth lens can have a negative refractive power, the fifth lens can have a positive refractive power, the sixth lens can have a negative refractive power, the seventh lens can have a positive refractive power, and the eighth lens can have a negative refractive power.

[0014] The first lens can have a negative refractive power, the second lens can have a positive refractive power, and the third lens can have a positive refractive power.

[0015] The fourth lens can have a negative refractive power, the fifth lens can have a positive refractive power, the sixth lens can have a positive refractive power, the seventh lens can have a positive refractive power, and the eighth lens can have a negative refractive power.

[0016] The first lens can have a positive refractive power, the second lens can have a negative refractive power, and the third lens can have a positive refractive power.

[0017] The fourth lens can have a negative refractive power, the fifth lens can have a positive refractive power, the sixth lens can have a positive refractive power, the seventh lens can have a negative refractive power, and the eighth lens can have a negative refractive power.

[0018] The optical imaging system can include a stop disposed between the first lens and the second lens.

[0019] Among the lenses, the eighth lens can have the smallest absolute value of focal length.

[0020] At least one of the lenses can have a positive refractive power and have a refractive index of 1.67 or more, and at least one of the lenses can have a negative refractive power and have a refractive index of 1.65 or more.

[0021] 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 arranged in order from an object side of the optical imaging system, an object side face of the first lens is convex, and an image side face of the first lens is concave, a refractive index of at least one of the lenses is 1.67 or more, and Fno < 1.9, where Fno is an F number of the imaging system including the first lens through the eighth lens.

[0022] At least one of the lenses can have a positive refractive power and have a refractive index of 1.67 or more, and at least one of the lenses can have a negative refractive power and have a refractive index of 1.65 or more.

[0023] The optical imaging system can satisfy FOV > 70°, where FOV is a field of view of the imaging system including the first lens through the eighth lens.

[0024] The optical imaging system can satisfy TTL / (2*IMG HT) < 0.9, where TTL is an optical axis distance from a subject side of the first lens to an image capturing surface of the image sensor, and IMG HT is half of a diagonal length of the image capturing surface of the image sensor.

[0025] 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 arranged in order from a subject side of the optical imaging system, and f / EPD < 1.9, where f is a total focal length of the imaging system including the first lens through the eighth lens, and EPD is an entrance pupil diameter of the imaging system.

[0026] At least four of the lenses can have positive refractive power.

[0027] Other features and aspects will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the application. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a view illustrating an optical imaging system according to a first example.

[0029] Figure 2 is a view illustrating Figure 1 aberration characteristics of the optical imaging system illustrated in FIG. 1.

[0030] Figure 3 is a view illustrating an optical imaging system according to a second example.

[0031] Figure 4 is a view illustrating Figure 3 aberration characteristics of the optical imaging system illustrated in FIG. 1.

[0032] Figure 5 is a view illustrating an optical imaging system according to a third example.

[0033] Figure 6 is a view illustrating Figure 5 aberration characteristics of the optical imaging system illustrated in FIG. 1.

[0034] Figure 7 is a view illustrating an optical imaging system according to a fourth example.

[0035] Figure 8 is a view illustrating Figure 7 aberration characteristics of the optical imaging system illustrated in FIG. 1.

[0036] Figure 9 is a view showing an optical imaging system according to a fifth example.

[0037] Figure 10 is a view showing Figure 9 aberration characteristics of the optical imaging system shown in

[0038] In all the drawings and specific embodiments, the same reference numerals refer to the same elements. The drawings can not be to scale and the relative dimensions, proportions and depiction of the elements in the drawings can be exaggerated for clarity, illustration and convenience. DETAILED DESCRIPTION

[0039] The following detailed description is provided to help the reader obtain a thorough understanding of the methods, devices, and / or systems described in this application. The various changes, modifications, and equivalents, which become apparent to those skilled in the art, are intended to be within the scope of the methods, devices, and / or systems described in this application. The sequence of operations in the methods described in this application are merely examples, and are not limited to the order described in this application, except where the order is essential, and can be changed, as will be apparent to one of ordinary skill in the art, without departing from the scope of the methods, devices, and / or systems described in this application. Also, descriptions of functions and constructions known in the art can be omitted for the sake of clarity and conciseness.

[0040] The features described in this application can be implemented in different forms and should not be construed as limited to the examples described in this application. Rather, the examples described in this application have been provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0041] Note that, in this application, the use of the phrase "may" with respect to examples or embodiments, for example, with respect to what an example or embodiment can include or implement, means that there is at least one example or embodiment in which the feature is included or implemented, and that all examples and embodiments are not limited to this.

[0042] Throughout the specification, when an element such as a layer, region, or substrate is referred to as being "on", "connected to", or "coupled to" another element, it can be directly on, directly connected to, or directly coupled to the other element, or one or more other elements can be interposed therebetween. Conversely, when an element is referred to as being "directly on", "directly connected to", or "directly coupled to" another element, there are no other elements interposed therebetween.

[0043] As used in this application, the words "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or variations thereof, do not have a limiting meaning and are used in their open-ended sense to encompass the items listed thereafter and any additional items.

[0044] Although the terms "first," "second," and "third" can be used herein to describe various elements, components, regions, layers, or sections, these elements, components, regions, layers, or sections should not be limited by these terms. Rather, these terms are used only to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section mentioned in one example can also be termed a second element, component, region, layer, or section in another example without departing from the teachings of the examples described herein.

[0045] Spatially relative terms such as "on", "upper", "lower", "above", "below", and "below" can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms can be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "upper" relative to other elements or features would then be oriented "below" or "lower" relative to the other elements or features. Accordingly, the expression "above" or "upper" can encompass both an orientation of above and below. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0046] The terminology used in this application is for the purpose of describing various examples only and is not intended to be limiting of the disclosure. The use of the singular herein includes the plural unless the context clearly dictates otherwise. The use of the term "a" or "an" herein does not exclude a plurality, and "comprises" or "comprising" does not exclude the presence of other elements or steps. Furthermore, unless otherwise noted, the use of the term "about" preceding a certainty or certainty range indicates that the value or range of values can vary by 1% or less of the stated value or range of values.

[0047] Variations can be made in the shape of the elements shown in the figures due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the precise shapes shown in the figures, but include variations in shapes that would occur to one of ordinary skill upon reading the present disclosure.

[0048] The features of the examples described herein can be combined in various ways without departing from the disclosure. Furthermore, although the examples described herein have a variety of configurations, other configurations are possible without departing from the teachings of the present disclosure.

[0049] In the drawings, the thickness, size, and shape of the lenses are exaggerated slightly for convenience of explanation. In particular, the shape of the spherical surface or aspherical surface shown in the drawings is merely illustrative. That is, the shape of the spherical surface or aspherical surface is not limited to those shown in the drawings.

[0050] In the present 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.

[0051] The first surface of each lens refers to the surface (or object side surface) of the lens closest to the object side, and the second surface of each lens refers to the surface (or image side surface) of the lens closest to the image side. In addition, all values of 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.

[0052] In addition, in the description of the shape of each lens, the meaning that one surface of the lens is convex is that the paraxial region of the corresponding surface is partially convex, and the meaning that one surface of the lens is concave is that the paraxial region of the corresponding surface is partially concave. Therefore, even when one surface of the lens is described as convex, the edge portion of the lens can be concave. In a similar manner, even when one surface of the lens is described as concave, the edge portion of the lens can be convex.

[0053] The paraxial region refers to a very narrow region including the optical axis.

[0054] The optical imaging system according to various examples can include eight lenses.

[0055] For example, the optical imaging system can include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in order from the object side. The first lens to the eighth lens are spaced apart from each other by a predetermined distance along the optical axis, respectively.

[0056] However, the optical imaging system is not limited to including only eight lenses, but can further include other components as necessary.

[0057] For example, the optical imaging system can further include an image sensor that converts an image of an object incident on the image sensor into an electrical signal.

[0058] The optical imaging system can further include an infrared filter (hereinafter referred to as a "filter") that cuts off infrared light. The filter can be disposed between the eighth lens and the image sensor.

[0059] The optical imaging system can further include a diaphragm that controls the amount of light.

[0060] In the optical imaging system, the first lens to the eighth lens can be formed of plastic.

[0061] At least one of the first to eighth lenses can have an aspheric surface. Also, each of the first to eighth lenses can have at least one aspheric surface.

[0062] At least one of the first and second surfaces of all of the first to eighth lenses can be aspheric. The aspheric surface of the first to eighth lenses can be represented by Equation 1 below.

[0063] Equation 1

[0064]

[0065] In Equation 1, c is a curvature of a lens (reciprocal of a radius of curvature), K is a conic constant, and Y is a distance from a certain point on the aspheric surface of the lens to an optical axis. Also, the constants A to I are aspheric coefficients. Also, Z is a distance from a certain point on the aspheric surface of the lens to a tangent plane intersecting a vertex of the aspheric surface of the lens.

[0066] An optical imaging system includes first to eighth lenses which can have positive power / positive power / positive power / negative power / positive power / negative power / positive power / negative power in order from an object side. Alternatively, the first to eighth lenses can have negative power / positive power / positive power / negative power / positive power / positive power / positive power / negative power. Alternatively, the first to eighth lenses can have positive power / negative power / positive power / negative power / positive power / positive power / negative power / negative power.

[0067] The optical imaging system according to various examples can satisfy the following conditional expressions:

[0068] Conditional expression 1: f / EPD < 1.9

[0069] Conditional expression 2: FOV > 70°

[0070] Conditional expression 3: TTL / (2*IMG HT) < 0.9

[0071] In the conditional expressions, f is a total focal length of the optical imaging system, EPD is an entrance pupil diameter, FOV is a field of view angle of the optical imaging system, TTL is an optical axis distance from an object side surface of the first lens to an image capturing surface of an image sensor, and IMG HT is half of a diagonal length of the image capturing surface of the image sensor.

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

[0073] The first lens can have a positive refractive power or a negative refractive power. The first lens can have a meniscus shape convex on the object side. The first face of the first lens can be convex, and the second face of the first lens can be concave.

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

[0075] The second lens can have a positive refractive power or a negative refractive power. Both faces of the second lens can be convex. For example, the first face and the second face of the second lens can be convex.

[0076] Optionally, the second lens can have a meniscus shape convex on the object side. For example, the first face of the second lens can be convex, and the second face of the second lens can be concave.

[0077] At least one of the first face and the second face of the second lens can be aspherical. For example, both faces of the second lens can be aspherical.

[0078] The third lens can have a positive refractive power. Both faces of the third lens can be convex. For example, the first face and the second face of the third lens can be convex.

[0079] Optionally, the third lens can have a meniscus shape convex on the object side. For example, the first face of the third lens can be convex in the paraxial region, and the second face of the third lens can be concave in the paraxial region.

[0080] At least one of the first face and the second face of the third lens can be aspherical. For example, both faces of the third lens can be aspherical.

[0081] At least one inflection point can be formed on at least one of the first face and the second face of the third lens. For example, the first face of the third lens can be convex in the paraxial region, and become concave toward the edge of the first face of the third lens.

[0082] The fourth lens can have a negative refractive power. The fourth lens can have a meniscus shape convex on the object side. For example, the first face of the fourth lens can be convex in the paraxial region, and the second face of the fourth lens can be concave in the paraxial region.

[0083] At least one of the first face and the second face of the fourth lens can be aspherical. For example, both faces of the fourth lens can be aspherical.

[0084] At least one inflection point can 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 can 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 can be concave in the paraxial region and become convex toward the edge of the second surface of the fourth lens.

[0085] The fifth lens can have a positive refractive power. The fifth lens can have a meniscus shape convex on the image side. For example, the first surface of the fifth lens can be concave, and the second surface of the fifth lens can be convex.

[0086] At least one of the first and second surfaces of the fifth lens can be aspherical. For example, both surfaces of the fifth lens can be aspherical.

[0087] The sixth lens can have a positive refractive power or a negative refractive power. The sixth lens can have a meniscus shape convex on the object side. For example, the first surface of the sixth lens can be convex in the paraxial region, and the second surface of the sixth lens can be concave in the paraxial region.

[0088] Alternatively, the sixth lens can have a meniscus shape convex on the image side. For example, the first surface of the sixth lens can be concave in the paraxial region, and the second surface of the sixth lens can be convex in the paraxial region.

[0089] At least one of the first and second surfaces of the sixth lens can be aspherical. For example, both surfaces of the sixth lens can be aspherical.

[0090] At least one inflection point can 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 can be convex in the paraxial region and become concave toward the edge of the first surface of the sixth lens. The second surface of the sixth lens can be concave in the paraxial region and become convex toward the edge of the second surface of the sixth lens.

[0091] The seventh lens can have a positive refractive power or a negative refractive power. Both surfaces of the seventh lens can be convex. For example, the first and second surfaces of the seventh lens can be convex in the paraxial region.

[0092] Alternatively, the seventh lens can have a meniscus shape convex on the image 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.

[0093] 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.

[0094] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the seventh lens.

[0095] The eighth lens can have a negative refractive power. The eighth lens can have a meniscus shape convex on the object side. For example, the first surface of the eighth lens can be convex in the paraxial region, and the second surface of the eighth lens can be concave in the paraxial region.

[0096] Alternatively, both the first and second 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.

[0097] At least one of the first and second surfaces of the eighth lens can be aspherical. For example, both the first and second surfaces of the eighth lens can be aspherical.

[0098] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the eighth lens. The second surface of the eighth lens can be concave in the paraxial region, and the edge of the second surface of the eighth lens can become convex.

[0099] The refractive index of at least one lens among the first to eighth lenses can be 1.68 or more.

[0100] Among the first to eighth lenses, the refractive index of at least one lens having a positive refractive power can be 1.67 or more, and the refractive index of at least one lens having a negative refractive power can be 1.65 or more.

[0101] Among the first to eighth lenses, the absolute value of the focal length of the eighth lens is the smallest.

[0102] In the optical imaging system configured as described above, the plurality of lenses can perform an aberration correction function to improve aberration improvement performance.

[0103] Hereinafter, referring to Figure 1 and Figure 2 An optical imaging system according to a first example is described.

[0104] The optical imaging system according to the first example can include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, and an eighth lens 180, and can further include a stop ST, a filter 190, and an image sensor 191.

[0105] The lens properties (radius of curvature, thickness of the lens or distance between the lenses, refractive index, Abbe number, and focal length) of each lens are shown in Table 1.

[0106] Table 1

[0107]

[0108] According to the first example, the total focal length f of the optical imaging system is 5.81 mm, the Fno is 1.87, the BFL is 1.09 mm, the FOV is 78.1°, and the IMG HT is 4.7 mm.

[0109] The Fno is a number indicating the brightness of the optical imaging system, the BFL is the distance from the image side surface of the eighth lens to the image capturing surface of the image sensor, the FOV is the field of view angle of the optical imaging system, and the IMG HT is half of the diagonal length of the image capturing surface of the image sensor.

[0110] In the first example, the first lens 110 can have a positive refractive power, and the first surface of the first lens 110 can be convex, and the second surface of the first lens 110 can be concave.

[0111] The second lens 120 can have a positive refractive power, and the first and second surfaces of the second lens 120 are convex.

[0112] The third lens 130 can have a positive refractive power, and the first and second surfaces of the third lens 130 are convex.

[0113] The fourth lens 140 can have a negative refractive power, and the first surface of the fourth lens 140 can be convex, and the second surface of the fourth lens 140 can be concave.

[0114] The fifth lens 150 can have a positive refractive power, and the first surface of the fifth lens 150 can be concave, and the second surface of the fifth lens 150 can be convex.

[0115] The sixth lens 160 can have a negative refractive power, and the first surface of the sixth lens 160 can be convex in the paraxial region, and the second surface of the sixth lens 160 can be concave in the paraxial region.

[0116] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the sixth lens 160. The second surface of the sixth lens 160 can be concave in the paraxial region, and become convex toward the edge of the second surface of the sixth lens 160.

[0117] The seventh lens 170 can have a positive refractive power, and the first and second surfaces of the seventh lens 170 can be convex in the paraxial region.

[0118] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the seventh lens 170.

[0119] The eighth lens 180 can have a negative refractive power, and the first surface of the eighth lens 180 can be convex in the paraxial region, and the second surface of the eighth lens 180 can be concave in the paraxial region.

[0120] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the eighth lens 180. The second surface of the eighth lens 180 can be concave in the paraxial region, and become convex toward the edge of the second surface of the eighth lens 180.

[0121] Each surface of the first to eighth lenses 110 to 180 can have an aspheric coefficient as shown in Table 2. For example, the object and image sides of the first to eighth lenses 110 to 180 can all be aspheric.

[0122] The stop ST can be disposed between the first and second lenses 110 and 120.

[0123] Table 2

[0124] 1 2 3 4 5 6 7 8 K -3.0581 -2.83302 0.0988 -51.46095 0.14986 -5.2952 43.43888 -7.06863 A -0.00838 0.01314 0.02096 0.00324 0.00935 -0.01212 -0.04563 -0.00996 B -0.00688 -0.05945 -0.06656 -0.03209 -0.03438 0.01148 0.08287 0.05288 C 0.00446 0.06895 0.08698 0.01892 0.03336 -0.04233 -0.17355 -0.08003 D -0.00009 -0.03853 -0.07421 0.01809 -0.007 0.09753 0.2722 0.0851 E -0.00099 0.01212 0.05083 -0.0341 -0.00846 -0.11845 -0.27352 -0.05429 F 0.00045 -0.00227 -0.02633 0.02332 0.00466 0.07798 0.16744 0.01762 G -9.45E-05 0.00025 0.00882 -0.00866 -0.00025 -0.02865 -0.06034 -0.0009 H 9.98E-06 -1.54E-05 -0.00163 0.00176 -0.00024 0.00558 0.01174 -0.001 I -4.37E-07 3.98E-07 0.00013 -0.00015 3.48E-05 -0.00045 -0.00095 0.00019 9 10 11 12 13 14 15 16 K 0 -0.17529 0.37407 -36.08796 1.10E-06 0.0817 -13.89285 -5.58556 A -0.02649 -0.02261 -0.01322 0.0579 0.04405 0.03749 -0.0796 -0.03729 B 0.05844 0.03642 0.01056 -0.05314 -0.03377 -0.0153 0.01971 0.00986 C -0.11232 -0.05534 -0.02313 0.02443 0.0119 0.00319 -0.00353 -0.00185 D 0.12164 0.04431 0.01914 -0.00689 -0.00306 -0.00045 0.00057 0.00023 E -0.07704 -0.02009 -0.00877 0.00124 0.00057 4.22E-05 -6.96E-05 -1.97E-05 F 0.02637 0.00484 0.0024 -0.00014 -7.15E-05 -2.29E-06 5.64E-06 1.08E-06 G -0.00312 -0.00038 -0.00039 9.96E-06 5.46E-06 5.22E-08 -2.81E-07 -3.60E-08 H -0.00057 -6.09E-05 3.57E-05 -3.90E-07 -2.30E-07 3.75E-10 7.81E-09 6.53E-10 I 0.00014 1.00E-05 -1.37E-06 6.50E-09 4.08E-09 -2.58E-11 -9.23E-11 -4.88E-12

[0125] Figure 1 The optical imaging system of claim 1 can have Figure 2 aberration characteristics as shown in Table 1.

[0126] Hereinafter, an optical imaging system according to a second example is described with reference to Figure 3 and Figure 4

[0127] The optical imaging system according to the second example can include a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, a seventh lens 270, and an eighth lens 280, and can further include a stop ST, a filter 290, and an image sensor 291.

[0128] Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are shown in Table 3.

[0129] Table 3​

[0130]

[0131] According to a second example, the total focal length f of the optical imaging system is 5.65 mm, the Fno is 1.79, the BFL is 1.00 mm, the FOV is 78.1°, and the IMG HT is 4.7 mm.

[0132] The Fno is a number indicating the brightness of the optical imaging system, the BFL is a distance from an image side surface of the eighth lens to an image capturing surface of the image sensor, the FOV is a field of view angle of the optical imaging system, and the IMG HT is half of a diagonal length of the image capturing surface of the image sensor.

[0133] In the second example, the first lens 210 can have a positive refractive power, and the first surface of the first lens 210 can be convex, and the second surface of the first lens 210 can be concave.

[0134] The second lens 220 can have a positive refractive power, and the first surface of the second lens 220 can be convex, and the second surface of the second lens 220 can be concave.

[0135] The third lens 230 can have a positive refractive power, and the first and second surfaces of the third lens 230 are convex.

[0136] The fourth lens 240 can have a negative refractive power, and the first surface of the fourth lens 240 can be convex, and the second surface of the fourth lens 240 can be concave.

[0137] The fifth lens 250 can have a positive refractive power, and the first surface of the fifth lens 250 can be concave, and the second surface of the fifth lens 250 can be convex.

[0138] The sixth lens 260 can have a negative refractive power, and the first surface of the sixth lens 260 can be convex in a paraxial region, and the second surface of the sixth lens 260 can be concave in the paraxial region.

[0139] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward an edge of the first surface of the sixth lens 260. The second surface of the sixth lens 260 can be concave in the paraxial region, and become convex toward an edge of the second surface of the sixth lens 260.

[0140] The seventh lens 270 can have a positive refractive power, and the first and second surfaces of the seventh lens 270 are convex in a paraxial region.

[0141] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the seventh lens 270.

[0142] The eighth lens 280 can have a negative refractive power, and the first surface of the eighth lens 280 can be convex in the paraxial region, and the second surface of the eighth lens 280 can be concave in the paraxial region.

[0143] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the eighth lens 280. The second surface of the eighth lens 280 can be concave in the paraxial region, and become convex toward the edge of the second surface of the eighth lens 280.

[0144] Each surface of the first to eighth lenses 210 to 280 can have an aspheric coefficient as shown in Table 4. For example, the object side surface and the image side surface of the first to eighth lenses 210 to 280 can all be aspheric.

[0145] The stop ST can be disposed between the first lens 210 and the second lens 220.

[0146] Table 4

[0147] 1 2 3 4 5 6 7 8 K -2.96193 -2.95518 0.10345 -51.46093 0.32489 -5.29525 43.29434 -7.06798 A -0.00808 0.0134 0.01989 0.00326 0.00924 -0.00953 -0.04336 -0.01001 B -0.00644 -0.05781 -0.06518 -0.03281 -0.03245 -0.00193 0.0721 0.0526 C 0.00357 0.06555 0.08998 0.01904 0.0281 -0.00968 -0.14683 -0.07992 D 0.00054 -0.03606 -0.08337 0.02151 0.00031 0.04793 0.22876 0.08785 E -0.00122 0.0112 0.06068 -0.03953 -0.01461 -0.06985 -0.22702 -0.06073 F 0.0005 -0.00208 -0.03191 0.02703 0.00797 0.04765 0.13586 0.02418 G -1.01E-04 0.00023 0.01059 -0.00997 -0.00135 -0.01703 -0.04742 -0.00444 H 1.04E-05 -1.38E-05 -0.00193 0.002 -0.00003 0.00309 0.00885 -0.00001 I -4.50E-07 3.53E-07 0.00015 -0.00017 1.83E-05 -0.00022 -0.00068 0.00008 9 10 11 12 13 14 15 16 K 0.00008 -0.25198 0.54881 -36.08638 1.10E-04 -0.01972 -13.89277 -5.38036 A -0.02799 -0.02393 -0.0126 0.05894 0.04212 0.03228 -0.07811 -0.03512 B 0.0642 0.04402 0.00834 -0.0554 -0.03097 -0.01066 0.01913 0.00893 C -0.12096 -0.06968 -0.02121 0.02604 0.01027 0.00131 -0.0034 -0.00162 D 0.12813 0.05973 0.01846 -0.00747 -0.00255 -0.00001 0.00054 0.0002 E -0.07878 -0.03034 -0.00868 0.00136 0.00048 -1.90E-05 -6.58E-05 -1.70E-05 F 0.02529 0.00904 0.00241 -0.00016 -6.07E-05 2.95E-06 5.29E-06 9.49E-07 G -0.00205 -0.00141 -0.0004 1.12E-05 4.71E-06 -2.14E-07 -2.62E-07 -3.23E-08 H -0.00091 7.57E-05 3.60E-05 -4.40E-07 -2.01E-07 7.73E-09 7.24E-09 5.97E-10 I 0.00018 2.46E-06 -1.38E-06 7.38E-09 3.60E-09 -1.11E-10 -8.54E-11 -4.51E-12

[0148] Figure 3 The optical imaging system of claim 1 can have Figure 4 aberration characteristics as shown in Table 2.

[0149] Hereinafter, an optical imaging system according to a third example is described with reference to Figure 5 and Figure 6 .

[0150] The optical imaging system according to the third example can include a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, a seventh lens 370, and an eighth lens 380, and can further include a stop ST, a filter 390, and an image sensor 391.

[0151] Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are shown in Table 5.

[0152] Table 5

[0153]

[0154] According to a third example, the total focal length f of the optical imaging system is 5.90 mm, the Fno is 1.88, the BFL is 1.05 mm, the FOV is 80.5°, and the IMG HT is 4.7 mm.

[0155] The Fno is a number indicating the brightness of the optical imaging system, the BFL is a distance from the image side surface of the eighth lens to the image capturing surface of the image sensor, the FOV is the field of view angle of the optical imaging system, and the IMG HT is half of the diagonal length of the image capturing surface of the image sensor.

[0156] In the third example, the first lens 310 can have a negative refractive power, and the first surface of the first lens 310 can be convex, and the second surface of the first lens 310 can be concave.

[0157] The second lens 320 can have a positive refractive power, and the first surface of the second lens 320 can be convex, and the second surface of the second lens 320 can be concave.

[0158] The third lens 330 can have a positive refractive power, and the first and second surfaces of the third lens 330 are convex.

[0159] The fourth lens 340 can have a negative refractive power, and the first surface of the fourth lens 340 can be convex, and the second surface of the fourth lens 340 can be concave.

[0160] The fifth lens 350 can have a positive refractive power, and the first surface of the fifth lens 350 can be concave, and the second surface of the fifth lens 350 can be convex.

[0161] The sixth lens 360 can have a negative refractive power, and the first surface of the sixth lens 360 can be convex in the paraxial region, and the second surface of the sixth lens 360 can be concave in the paraxial region.

[0162] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the sixth lens 360. The second surface of the sixth lens 360 can be concave in the paraxial region, and become convex toward the edge of the second surface of the sixth lens 360.

[0163] The seventh lens 370 can have a positive refractive power, and the first and second surfaces of the seventh lens 370 are convex in the paraxial region.

[0164] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward the edge of the first surface of the seventh lens 370.

[0165] The eighth lens 380 can have a negative refractive power, and a first surface of the eighth lens 380 can be convex in the paraxial region, and a second surface of the eighth lens 380 can be concave in the paraxial region.

[0166] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward an edge of the first surface of the eighth lens 380. The second surface of the eighth lens 380 can be concave in the paraxial region, and become convex toward an edge of the second surface of the eighth lens 380.

[0167] Each surface of the first lens 310 to the eighth lens 380 can have an aspheric coefficient as shown in Table 6. For example, the object side surface and the image side surface of the first lens 310 to the eighth lens 380 can all be aspheric.

[0168] The stop ST can be disposed between the first lens 310 and the second lens 320.

[0169] Table 6

[0170]

[0171]

[0172] Figure 5 The optical imaging system of claim 1 can have Figure 6 aberration characteristics as shown in Table 1.

[0173] Hereinafter, an optical imaging system according to a fourth example is described with reference to Figure 7 and Figure 8 Table 1.

[0174] The optical imaging system according to the fourth example can include a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, a seventh lens 470, and an eighth lens 480, and can further include a stop ST, a filter 490, and an image sensor 491.

[0175] Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are shown in Table 7.

[0176] Table 7

[0177]

[0178]

[0179] According to a fourth example, a total focal length f of the optical imaging system is 5.86 mm, an Fno is 1.82, a BFL is 1.04 mm, a FOV is 80.5°, and an IMG HT is 4.7 mm.

[0180] The Fno is a number indicating brightness of the optical imaging system, the BFL is a distance from an image side surface of the eighth lens to an image capturing surface of the image sensor, the FOV is a field of view angle of the optical imaging system, and the IMG HT is half of a diagonal length of the image capturing surface of the image sensor.

[0181] In the fourth example, the first lens 410 can have a negative refractive power, and a first surface of the first lens 410 can be convex, and a second surface of the first lens 410 can be concave.

[0182] The second lens 420 can have a positive refractive power, and a first surface of the second lens 420 can be convex, and a second surface of the second lens 420 can be concave.

[0183] The third lens 430 can have a positive refractive power, and a first surface and a second surface of the third lens 430 are convex.

[0184] The fourth lens 440 can have a negative refractive power, and a first surface of the fourth lens 440 can be convex, and a second surface of the fourth lens 440 can be concave.

[0185] The fifth lens 450 can have a positive refractive power, and a first surface of the fifth lens 450 can be concave, and a second surface of the fifth lens 450 can be convex.

[0186] The sixth lens 460 can have a positive refractive power, and a first surface of the sixth lens 460 can be convex in a paraxial region, and a second surface of the sixth lens 460 can be concave in the paraxial region.

[0187] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward an edge of the first surface of the sixth lens 460. The second surface of the sixth lens 460 can be concave in the paraxial region, and become convex toward an edge of the second surface of the sixth lens 460.

[0188] The seventh lens 470 can have a positive refractive power, and a first surface and a second surface of the seventh lens 470 are convex in a paraxial region.

[0189] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward an edge of the first surface of the seventh lens 470.

[0190] The eighth lens 480 can have a negative refractive power, and a first surface of the eighth lens 480 can be convex in the paraxial region, and a second surface of the eighth lens 480 can be concave in the paraxial region.

[0191] At least one inflection point can 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 can be convex in the paraxial region, and become concave toward an edge of the first surface of the eighth lens 480. The second surface of the eighth lens 480 can be concave in the paraxial region, and become convex toward an edge of the second surface of the eighth lens 480.

[0192] Each surface of the first lens 410 to the eighth lens 480 can have an aspheric coefficient as shown in Table 8. For example, the object side surface and the image side surface of the first lens 410 to the eighth lens 480 can all be aspheric.

[0193] The stop ST can be disposed between the first lens 410 and the second lens 420.

[0194] Table 8

[0195]

[0196]

[0197] Figure 7 The optical imaging system according to the fifth example can have Figure 8 aberration characteristics as shown in Table 9.

[0198] Hereinafter, an optical imaging system according to a fifth example is described with reference to Figure 9 and Figure 10 The optical imaging system according to the fifth example can include a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560, a seventh lens 570, and an eighth lens 580, and can further include a stop ST, a filter 590, and an image sensor 591.

[0199] Lens characteristics (a radius of curvature, a thickness of a lens or a distance between lenses, a refractive index, an Abbe number, and a focal length) of each lens are shown in Table 9.

[0200] Table 9

[0201] Table 9

[0202]

[0203]

[0204] According to a fifth example, a total focal length f of the optical imaging system is 5.69 mm, an Fno is 1.74, a BFL is 1.09 mm, a FOV is 80.5°, and an IMG HT is 4.7 mm.

[0205] The Fno is a number indicating brightness of the optical imaging system, the BFL is a distance from an image side surface of the eighth lens to an image capturing surface of the image sensor, the FOV is a field of view angle of the optical imaging system, and the IMG HT is half of a diagonal length of the image capturing surface of the image sensor.

[0206] In the fifth example, the first lens 510 can have a positive refractive power, and a first surface of the first lens 510 can be convex, and a second surface of the first lens 510 can be concave.

[0207] The second lens 520 can have a negative refractive power, and a first surface of the second lens 520 can be convex, and a second surface of the second lens 520 can be concave.

[0208] The third lens 530 can have a positive refractive power, and a first surface of the third lens 530 can be convex in a paraxial region, and a second surface of the third lens 530 can be concave in the paraxial region.

[0209] At least one inflection point can be formed on at least one of the first and second surfaces of the third lens 530. For example, the first surface of the third lens 530 can be convex in the paraxial region, and become concave toward an edge of the first surface of the third lens 530.

[0210] The fourth lens 540 can have a negative refractive power, and a first surface of the fourth lens 540 can be convex in a paraxial region, and a second surface of the fourth lens 540 can be concave in the paraxial region.

[0211] At least one inflection point can be formed on at least one of the first and second surfaces of the fourth lens 540. For example, the first surface of the fourth lens 540 can be convex in the paraxial region, and become concave toward an edge of the first surface of the fourth lens 540. The second surface of the fourth lens 540 can be concave in the paraxial region, and become convex toward an edge of the second surface of the fourth lens 540.

[0212] The fifth lens 550 can have a positive refractive power, and a first surface of the fifth lens 550 can be concave, and a second surface of the fifth lens 550 can be convex.

[0213] The sixth lens 560 can have a positive refractive power, and a first surface of the sixth lens 560 can be concave in a paraxial region, and a second surface of the sixth lens 560 can be convex in the paraxial region.

[0214] At least one inflection point can be formed on at least one of the first and second surfaces of the sixth lens 560. For example, the first surface of the sixth lens 560 can be concave in the paraxial region, and become convex toward the edge of the first surface of the sixth lens 560.

[0215] The seventh lens 570 can have a negative refractive power, and the first surface of the seventh lens 570 can be concave in the paraxial region, and the second surface of the seventh lens 570 can be convex in the paraxial region.

[0216] The eighth lens 580 can have a negative refractive power, and the first and second surfaces of the eighth lens 580 can be concave in the paraxial region.

[0217] At least one inflection point can be formed on at least one of the first and second surfaces of the eighth lens 580. For example, the first surface of the eighth lens 580 can be concave in the paraxial region, and become convex toward the edge of the first surface of the eighth lens 580. The second surface of the eighth lens 580 can be concave in the paraxial region, and become convex toward the edge of the second surface of the eighth lens 580.

[0218] Each surface of the first to eighth lenses 510 to 580 can have an aspheric coefficient as shown in Table 10. For example, the object side surface and the image side surface of the first to eighth lenses 510 to 580 can all be aspheric.

[0219] The stop ST can be disposed between the first lens 510 and the second lens 520.

[0220] Table 10

[0221]

[0222]

[0223] Figure 9 The optical imaging system of claim 1 can have Figure 10 aberration characteristics as shown in Table 10.

[0224] As described above, according to each example, since the optical imaging system, it is possible to improve the aberration improvement effect while achieving high resolution.

[0225] While the present disclosure includes specific examples, it will be apparent to one of ordinary skill in the art, having the benefit of this disclosure, that various changes in form and detail can 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 in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each example should be considered as being applicable to similar features or aspects in other examples. Suitable results can be achieved if the described techniques are performed in a different order, and / or if the described systems, architectures, devices, or circuits are combined or substituted with other components or their equivalents. Therefore, the scope of the present disclosure should not be deemed limited to the specific examples described herein, but should be understood to include any and all variations that are within the scope of the appended claims and their equivalents.

Claims

1. An optical imaging system characterized by, The optical imaging system comprises: 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 order from an object side of the optical imaging system, wherein a refractive index of at least one of the first lens to the eighth lens is 1.67 or more, wherein a number of lenses having refractive power in the optical imaging system is eight, wherein the first lens has negative refractive power, the second lens has positive refractive power, the third lens has positive refractive power, the fourth lens has negative refractive power, the fifth lens has positive refractive power, the sixth lens has positive refractive power, the seventh lens has positive refractive power, the eighth lens has negative refractive power, the first lens has a convex object side surface, and the fourth lens has a convex object side surface, and wherein an absolute value of a focal length of the eighth lens is the smallest among the first lens to the eighth lens.

2. The optical imaging system of claim 1, wherein, FOV > 70°, wherein FOV is a field of view of an imaging system including the first lens to the eighth lens.

3. The optical imaging system of claim 1, wherein, f / EPD < 1.9, wherein f is a total focal length of an imaging system including the first lens to the eighth lens, and EPD is an entrance pupil diameter of the imaging system.

4. The optical imaging system of claim 1, wherein, The optical imaging system further comprises a stop disposed between the first lens and the second lens.

5. The optical imaging system of claim 1, wherein, At least one of the first lens to the eighth lens has positive refractive power and has a refractive index of 1.67 or more, and at least one of the first lens to the eighth lens has negative refractive power and has a refractive index of 1.65 or more.

6. An optical imaging system characterized by, The optical imaging system comprises: 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 order from an object side of the optical imaging system, wherein an object side surface of the first lens is convex, and an image side surface of the first lens is concave, a refractive index of at least one of the first lens to the eighth lens is 1.67 or more, and Fno < 1.9, wherein Fno is an F number of an imaging system including the first lens to the eighth lens, wherein a number of lenses having refractive power in the optical imaging system is eight, wherein the first lens has negative refractive power, the second lens has positive refractive power, the third lens has positive refractive power, the fourth lens has negative refractive power, the fifth lens has positive refractive power, the sixth lens has positive refractive power, the seventh lens has positive refractive power, the eighth lens has negative refractive power, and the fourth lens has a convex object side surface, and wherein an absolute value of a focal length of the eighth lens is the smallest among the first lens to the eighth lens.

7. The optical imaging system of claim 6, wherein, At least one of the first lens to the eighth lens has positive refractive power and has a refractive index of 1.67 or more, and at least one of the first lens to the eighth lens has negative refractive power and has a refractive index of 1.65 or more.

8. The optical imaging system of claim 6, wherein, FOV > 70°, wherein FOV is a field of view of an imaging system comprising the first lens through the eighth lens.

9. The optical imaging system of claim 6, wherein, TTL / (2 IMG HT) < 0.9, where TTL is the distance along the optical axis from the object side surface of the first lens to the image capturing surface of the image sensor, and IMG HT is half the diagonal length of the image capturing surface of the image sensor.

10. An optical imaging system characterized by, The optical imaging system comprises: 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 order from an object side of the optical imaging system, wherein f / EPD < 1.9, wherein f is a total focal length of an imaging system comprising the first lens through the eighth lens, and EPD is an entrance pupil diameter of the imaging system, wherein a number of lenses having refractive power in the optical imaging system is eight, wherein the first lens has negative refractive power, the second lens has positive refractive power, the third lens has positive refractive power, the fourth lens has negative refractive power, the fifth lens has positive refractive power, the sixth lens has positive refractive power, the seventh lens has positive refractive power, the eighth lens has negative refractive power, and the fourth lens has a convex object side face, and wherein among the first lens through the eighth lens, the eighth lens has the smallest absolute value of focal length.

Images