Imaging lens system

Abstract

An imaging lens system includes, in order from an object side to an image plane, a first lens, a second lens having a negative refractive power, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens having a concave object side surface in a paraxial region. The imaging lens system satisfies TTL / IMGHT < 1.5, where TTL is a distance from an object side surface of the first lens to the image plane, and IMGHT is half of a diagonal length of the image plane.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2019-0152526, filed with the Korean Intellectual Property Office on November 25, 2019, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The following description pertains to an imaging lens system comprising eight lenses. Background Technology

[0004] Small cameras can be mounted on wireless terminal devices. For example, a small camera can be mounted on each of the front and rear surfaces of a wireless terminal device. Since such small cameras can be used for various purposes, such as acquiring images of landscapes, indoor portraits, etc., they need to have performance similar to that of ordinary cameras. However, the limited size of wireless terminal devices can restrict installation space, making it difficult for small cameras to achieve high performance. Therefore, there is a need to develop an imaging lens system that can improve the performance of small cameras without increasing their size. Summary of the Invention

[0005] 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.

[0006] An imaging lens system is provided that can improve the performance of small cameras.

[0007] In one general aspect, the imaging lens system includes a first lens, a second lens having negative refractive power, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens having a concave object-side surface in the paraxial region, arranged sequentially in the direction from the object side to the imaging plane. The imaging lens system satisfies TTL / IMGHT < 1.5, where TTL is the distance from the object-side surface of the first lens to the imaging plane, and IMGHT is half the diagonal length of the imaging plane.

[0008] The second lens can have a concave image-side surface.

[0009] The fourth lens can have positive refractive power.

[0010] The fifth lens can have a concave image-side surface.

[0011] The sixth lens can have negative refractive power.

[0012] The seventh lens can have a positive refractive power.

[0013] The imaging lens system can satisfy 0.5 < f1 / f < 1.0, where f is a focal length of the imaging lens system, and f1 is a focal length of the first lens.

[0014] The second lens can have an Abbe number less than 40.

[0015] The imaging lens system can satisfy 0.05 < TTL / FOV < 0.2, where FOV is a field of view angle of the imaging lens system.

[0016] The imaging lens system can satisfy 0.2 < T8 / T7 < 0.9, where T7 is a thickness of the seventh lens along an optical axis at a center thereof, and T8 is a thickness of the eighth lens along the optical axis at a center thereof.

[0017] In another general aspect, an imaging lens system includes, in order from an object side to an image plane, a first lens, a second lens having a negative refractive power, a third lens, a fourth lens, a fifth lens, a sixth lens having a concave image side surface, a seventh lens, and an eighth lens having a concave object side surface.

[0018] The imaging lens system can have an F number of 1.7 or less.

[0019] The imaging lens system can satisfy -4.0 < f2 / f1 < -2.0, where f1 is a focal length of the first lens, and f2 is a focal length of the second lens.

[0020] The imaging lens system can satisfy 0.2 < f2 / f3 < 0.5, where f2 is a focal length of the second lens, and f3 is a focal length of the third lens.

[0021] The imaging lens system can satisfy -5.0 < f6 / f7 < -2.0, where f6 is a focal length of the sixth lens, and f7 is a focal length of the seventh lens.

[0022] The imaging lens system can satisfy -3.0 < f7 / f8 < -1.0, where f7 is a focal length of the seventh lens, and f8 is a focal length of the eighth lens.

[0023] In another general aspect, an imaging lens system includes, disposed in order from an object side to an image plane, a first lens having positive refractive power, a second lens having negative refractive power, a third lens having negative refractive power, a fourth lens having refractive power, a fifth lens having refractive power, a sixth lens having negative refractive power, a seventh lens having positive refractive power, and an eighth lens having negative refractive power. The imaging lens system satisfies TTL / IMGHT < 1.5, where TTL is a distance from an object side surface of the first lens to the image plane, and IMGHT is half of a diagonal length of the image plane.

[0024] The first lens through the seventh lens can be meniscus lenses, and the eighth lens can be a double concave lens.

[0025] The first lens can be thicker than each of the other lenses along the optical axis.

[0026] The second lens can be thinner than each of the other lenses along the optical axis.

[0027] Other features and aspects will become apparent from the following specific description, drawings and appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a diagram illustrating a first example of an imaging lens system.

[0029] Figure 2 is Figure 1 aberration curves of the imaging lens system illustrated in FIG. 1.

[0030] Figure 3 is a diagram illustrating a second example of an imaging lens system.

[0031] Figure 4 is Figure 3 aberration curves of the imaging lens system illustrated in FIG. 3.

[0032] Figure 5 is a diagram illustrating a third example of an imaging lens system.

[0033] Figure 6 is Figure 5 aberration curves of the imaging lens system illustrated in FIG. 5.

[0034] Figure 7 is a diagram illustrating a fourth example of an imaging lens system.

[0035] Figure 8 is Figure 7 aberration curves of the imaging lens system illustrated in FIG. 7.

[0036] Figure 9 is a diagram illustrating a fifth example of an imaging lens system.

[0037] Figure 10 is Figure 9 aberration curves of the imaging lens system shown in FIGS. 1A and 1B.

[0038] Throughout the drawings and detailed description, identical reference numbers indicate similar or identical elements. The drawings can not be to scale and the relative dimensions of the depicted elements can be exaggerated for clarity. 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 methods, devices, and / or systems described in this application, however, are capable of various changes, modifications, and equivalents and accordingly it should be understood that various changes, modifications and equivalents can be made thereto without departing from the scope of the present application.

[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, these examples are 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] It should be noted that, in this application, the use of the phrase "may", for example, in relation to what an example or embodiment can include or implement, means that there is at least one example or embodiment in which that 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, connected or 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, no other elements are interposed therebetween.

[0043] As used in this application, the term "and / or" includes any one of the associated listed items, as well as any combination of any two or more of the associated listed items.

[0044] Although terminology can be used in this application, such as "first", "second", and "third", to describe various components, parts, regions, layers or sections, these components, parts, regions, layers or sections are not limited by the terminology. Rather, these terms are used only to distinguish one component, part, region, layer or section from another component, part, region, layer or section. Thus, a first component, part, region, layer or section mentioned in the examples can also be called a second component, part, region, layer or section without departing from the teachings of the examples described in this application.

[0045] Spatially relative terms such as "on", "upper", "lower", "below", and "above" 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 "on" 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 "on" can encompass both an "on" and "below" orientation. 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 present disclosure. The use of the singular herein includes the plural unless the context clearly dictates otherwise. The use of the term "including" as well as "comprising" as used herein is intended to represent a non- limiting inclusion of a feature, number, operation, component, element, or combination thereof, but does not exclude the presence or addition of one or more other features, numbers, operations, components, elements, or combinations thereof.

[0047] Variations can occur in the shapes of the elements depicted in the figures due to differences in manufacturing techniques and / or tolerances. Therefore, the examples described in this application are not limited to the specific shapes of the elements shown in the figures, but include deviations in shapes that occur due to manufacturing techniques and / or tolerances.

[0048] Features of the examples described in this application can be combined with each other in a manner that will be apparent after a study of the disclosures of this application. In addition, while the examples described in this application have various configurations, other configurations are possible after a study of the disclosures of this application.

[0049] The accompanying drawings can not be drawn to scale and the relative dimensions, proportions, and depiction of the elements in the drawings can be exaggerated for clarity, illustration, and convenience.

[0050] In an example, the first lens refers to a lens closest to an object (or a subject), and the eighth lens refers to a lens closest to an imaging surface (or an image sensor). In an example, a unit of a radius of curvature, a unit of a thickness, a unit of a TTL (a distance from an object side surface of the first lens to the imaging surface), a unit of 2IMGHT (a diagonal length of the imaging surface), and a unit of a focal length are expressed in millimeters (mm). A unit of FOV is expressed in degrees (°).

[0051] A thickness of a lens, a gap between lenses, and a TTL refer to a distance on an optical axis. In addition, in a description of a shape of a lens, a configuration in which one surface is convex means that an optical axis region of the surface is convex, and a configuration in which one surface is concave means that an optical axis region of the surface is concave. Thus, even when it is described that one surface of a lens is convex, an edge of the lens can be concave. Similarly, even when it is described that one surface of a lens is concave, an edge of the lens can be convex.

[0052] The imaging lens system can include eight lenses. For example, the imaging lens 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 disposed in order from an object side. The first lens to the eighth lens can be disposed with a predetermined gap therebetween. For example, an image side surface and an object side surface of adjacent lenses do not contact each other in a paraxial region. Thus, even when an image side surface of one side lens in a drawing contacts an object side surface of the other side lens, the image side surface and the object side surface of the two lenses do not actually contact each other.

[0053] The first lens can have a refractive power. One surface of the first lens can be convex. For example, the first lens can have a convex object side surface. The first lens can include an aspheric surface. For example, both surfaces of the first lens can be aspheric. The first lens can be formed of a material having high light transmittance and excellent machinability. For example, the first lens can be manufactured using a plastic material. The first lens can have a predetermined refractive index. For example, the refractive index of the first lens can be less than 1.6. The first lens can have a predetermined Abbe number. For example, the Abbe number of the first lens can be 50 or more. The first lens can have a predetermined focal length. For example, the focal length of the first lens can be 4.0 mm to 6.8 mm.

[0054] The second lens can have a refractive power. For example, the second lens can have a negative refractive power. One surface of the second lens can be concave. For example, the second lens can have a concave image-side surface. The second lens can include aspherical surfaces. For example, both surfaces of the second lens can be aspherical. The second lens can be formed of a material having high light transmittance and excellent machinability. For example, the second lens can be manufactured using a plastic material. The second lens can have a predetermined refractive index. For example, the refractive index of the second lens can be 1.6 or more. The second lens can have a predetermined Abbe number. For example, the Abbe number of the second lens can be less than 23. The second lens can have a predetermined focal length. For example, the focal length of the second lens can be -20 mm to -10 mm.

[0055] The third lens can have a refractive power. One surface of the third lens can be convex. For example, the third lens can have a convex object-side surface. The third lens can include aspherical surfaces. For example, both surfaces of the third lens can be aspherical. The third lens can be formed of a material having high light transmittance and excellent machinability. For example, the third lens can be manufactured using a plastic material. The third lens can have a refractive index greater than that of the first lens. For example, the refractive index of the third lens can be 1.6 or more. The third lens can have a predetermined Abbe number. For example, the Abbe number of the third lens can be less than 23. The third lens can have a predetermined focal length. For example, the focal length of the third lens can be -65 mm to -30 mm.

[0056] The fourth lens can have a refractive power. One surface of the fourth lens can be convex. For example, the fourth lens can have a convex object-side surface. The fourth lens can include aspherical surfaces. For example, both surfaces of the fourth lens can be aspherical. The fourth lens can be formed of a material having high light transmittance and excellent machinability. For example, the fourth lens can be manufactured using a plastic material. The fourth lens can have a refractive index less than that of the third lens. For example, the refractive index of the fourth lens can be less than 1.6. The fourth lens can have a predetermined Abbe number. For example, the Abbe number of the fourth lens can be greater than the Abbe number of the third lens. The fourth lens can have a predetermined focal length. For example, the focal length of the fourth lens can be less than -100 mm or 30 mm or more.

[0057] The fifth lens can have a refractive power. One surface of the fifth lens can be concave. For example, the fifth lens can have a concave image-side surface. The fifth lens can have a shape with a point of inflection. For example, at least one of the object-side surface and the image-side surface of the fifth lens can have a point of inflection. The fifth lens can include an aspheric surface. For example, both surfaces of the fifth lens can be aspheric. The fifth lens can be formed of a material having high light transmittance and excellent machinability. For example, the fifth lens can be manufactured using a plastic material. The fifth lens can have a predetermined refractive index. For example, the fifth lens can have a refractive index less than that of the third lens. The fifth lens can have a predetermined Abbe number. For example, the Abbe number of the fifth lens can be greater than that of the third lens. The fifth lens can have a predetermined focal length. For example, the focal length of the fifth lens can be -50 mm or less or 30 mm or more.

[0058] The sixth lens can have a refractive power. One surface of the sixth lens can be convex. For example, the sixth lens can have a convex object-side surface. The sixth lens can have a shape with a point of inflection. For example, at least one of the object-side surface and the image-side surface of the sixth lens can have a point of inflection. The sixth lens can include an aspheric surface. For example, both surfaces of the sixth lens can be aspheric. The sixth lens can be formed of a material having high light transmittance and excellent machinability. For example, the sixth lens can be manufactured using a plastic material. The sixth lens can have a predetermined refractive index. For example, the refractive index of the sixth lens can be greater than or equal to that of the fifth lens. The sixth lens can have a predetermined Abbe number. For example, the Abbe number of the sixth lens can be 25 or more and less than 40. The sixth lens can have a predetermined focal length. For example, the focal length of the sixth lens can be -38 mm to -10 mm.

[0059] The seventh lens can have a refractive power. One surface of the seventh lens can be convex. For example, the seventh lens can have a convex object-side surface. The seventh lens can have a shape with a point of inflection. For example, at least one of the object-side surface and the image-side surface of the seventh lens can have a point of inflection. The seventh lens can include an aspheric surface. For example, both surfaces of the seventh lens can be aspheric. The seventh lens can be formed of a material having high light transmittance and excellent machinability. For example, the seventh lens can be manufactured using a plastic material. The seventh lens can have a predetermined refractive index. For example, the refractive index of the seventh lens can be less than that of the sixth lens. The seventh lens can have an Abbe number greater than that of the sixth lens. For example, the Abbe number of the seventh lens can be 50 or more. The seventh lens can have a predetermined focal length. For example, the focal length of the seventh lens can be 3.6 mm to 7.4 mm.

[0060] The eighth lens can have a refractive power. At least one surface of the eighth lens can be concave. For example, the eighth lens can have a concave image side surface in a paraxial region. The eighth lens can have a shape with a point of inflection. For example, at least one of the object side surface and the image side surface of the eighth lens can have a point of inflection. The eighth lens can include aspheric surfaces. For example, both surfaces of the eighth lens can be aspheric. The eighth lens can be formed of a material having high light transmittance and excellent processability. For example, the eighth lens can be manufactured using a plastic material. The eighth lens can have a predetermined refractive index. For example, the refractive index of the eighth lens can be less than the refractive index of the sixth lens. The eighth lens can have an Abbe number greater than the Abbe number of the sixth lens. For example, the Abbe number of the eighth lens can be 50 or more. The eighth lens can have a predetermined focal length. For example, the focal length of the eighth lens can be -6.2 mm to -3.1 mm.

[0061] In the imaging lens system, the first lens can be the thickest lens. For example, the thickness of the first lens along the optical axis at its center can be greater than the thickness of the other lenses (the second lens to the eighth lens) along the optical axis at their respective centers.

[0062] In the imaging lens system, the second lens can be the thinnest lens. For example, the thickness of the second lens along the optical axis at its center can be less than the thickness of the other lenses (the first lens and the third lens to the eighth lens) along the optical axis at their respective centers.

[0063] Each of the first lens to the eighth lens can include an aspheric surface. The aspheric surface of each of the first lens to the eighth lens can be represented by Equation 1 below:

[0064] [Equation 1]

[0065]

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

[0067] The imaging lens system can further include a filter, an image sensor, and a stop. The filter can be disposed between the eighth lens and the image sensor. The filter can be configured to block light of a specific wavelength. For example, the filter can block light of an infrared wavelength. The image sensor can form an imaging plane. For example, the surface of the image sensor can form the imaging plane. The stop can be arranged to adjust the amount of light incident to the lens. For example, the stop can be disposed between the second lens and the third lens.

[0068] The imaging lens system can have a predetermined focal length. For example, the focal length f of the imaging lens system can be 5.6 mm to 7.0 mm. The imaging lens system can have a rather large size of imaging plane to achieve high resolution. For example, the diagonal length (2IMGHT) of the imaging plane of the imaging lens system can be 10 mm to 14 mm.

[0069] The imaging lens system can satisfy one or more of the following conditional expressions:

[0070] TTL / IMGHT < 1.5

[0071] 0.05 < TTL / FOV < 0.2

[0072] 0.2 < T8 / T7 < 0.9

[0073] F number < 1.7

[0074] 78° < FOV < 85°

[0075] 0.5 < f1 / f < 1.0

[0076] -4.0 < f2 / f1 < -2.0

[0077] 0.2 < f2 / f3 < 0.5

[0078] -5.0 < f6 / f7 < -2.0

[0079] -3.0 < f7 / f8 < -1.0

[0080] In the conditional expressions, TTL is a distance from an object side surface of the first lens to the imaging plane, IMGHT is 1 / 2 of a diagonal length of the imaging plane, T7 is a thickness of the seventh lens at a center thereof along an optical axis, T8 is a thickness of the eighth lens at a center thereof along the optical axis, FOV is a field angle of the imaging lens system, f is a focal length of the imaging lens system, f1 is a focal length of the first lens, f2 is a focal length of the second lens, f3 is a focal length of the third lens, f6 is a focal length of the sixth lens, f7 is a focal length of the seventh lens, and f8 is a focal length of the eighth lens.

[0081] The imaging lens system can also satisfy one or more of the following conditional expressions:

[0082] 0.4 < f1 / f7 < 1.2

[0083] -1.4 < f1 / f8 < -0.4

[0084] 18 < (V2+V3) / 2 < 22

[0085] V2 < 40

[0086] V3 < V6 < V7

[0087] T5 < T4

[0088] 2.0 < (R11 + R12) / (R11 - R12) < 5.0

[0089] 0.72 < DL1L4 / DL5L8 < 0.82

[0090] 1.06 < f / IMGHT < 1.12

[0091] In the above conditional expressions, V2 is the Abbe number of the second lens, V3 is the Abbe number of the third lens, V6 is the Abbe number of the sixth lens, V7 is the Abbe number of the seventh lens, T4 is the thickness of the fourth lens along the optical axis at its center, T5 is the thickness of the fifth lens along the optical axis at its center, R11 is the radius of curvature of the object side surface of the sixth lens, R12 is the radius of curvature of the image side surface of the sixth lens, DL1L4 is the distance from the object side surface of the first lens to the image side surface of the fourth lens, and DL5L8 is the distance from the object side surface of the fifth lens to the image side surface of the eighth lens.

[0092] The imaging lens system can also satisfy one or more of the following conditional expressions:

[0093] F number < 1.64

[0094] 0.4 < |f3 / f5| < 1.6

[0095] 2.0 < (R5 + R6) / (R5 - R6) < 4.0

[0096] -2.0 < (R13 + R14) / (R13 - R14) < -0.8

[0097] 1.0 < f / f7 < 1.3

[0098] In the above conditional expressions, R5 is the radius of curvature of the object side surface of the third lens, R6 is the radius of curvature of the image side surface of the third lens, R13 is the radius of curvature of the object side surface of the seventh lens, and R14 is the radius of curvature of the image side surface of the seventh lens.

[0099] In the following description, various examples of the imaging lens system will be described.

[0100] Reference will be made to Figure 1 A first example of the imaging lens system will be described.

[0101] The imaging lens system 100 can include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, and an eighth lens 180.

[0102] The first lens 110 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 120 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 130 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 140 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 150 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. A inflection point can be formed on at least one of the object side surface and the image side surface of the fifth lens 150. The sixth lens 160 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. A inflection point can be formed on at least one of the object side surface and the image side surface of the sixth lens 160. The seventh lens 170 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. A inflection point can be formed on at least one of the object side surface and the image side surface of the seventh lens 170. The eighth lens 180 can have a negative refractive power, and a concave object side surface and a concave image side surface. A inflection point can be formed on at least one of the object side surface and the image side surface of the eighth lens 180.

[0103] The imaging lens system 100 can further include an optical filter IF, an image sensor IMG, and a stop ST. The optical filter IF can be disposed between the eighth lens 180 and the image sensor IMG. The image sensor IMG can provide a surface on which light refracted by the first lens 110 to the eighth lens 180 is formed. One surface of the image sensor IMG can be substantially the same size as the imaging surface. For example, a diagonal length (2IMGHT) of the imaging surface refers to a diagonal length of the image sensor IMG, and a height of the imaging surface can refer to a distance from a center of an optical axis of the image sensor IMG to an edge. The stop ST can be disposed between the second lens 120 and the third lens 130.

[0104] Table 1 and Table 2 list lens properties and aspherical values of the imaging lens system 100. Figure 2 is an aberration curve of the imaging lens system 100 of the above-described configuration.

[0105] Table 1

[0106]

[0107] Table 2

[0108]

[0109] A second example of an imaging lens system will be described with reference to Figure 3

[0110] ​The imaging lens system 200 can include a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, a seventh lens 270, and an eighth lens 280.

[0111] The first lens 210 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 220 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 230 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 240 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 250 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the fifth lens 250. The sixth lens 260 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the sixth lens 260. The seventh lens 270 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the seventh lens 270. The eighth lens 280 can have a negative refractive power, and can have a concave object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the eighth lens 280.

[0112] The imaging lens system 200 can further include an optical filter IF, an image sensor IMG, and a stop ST. The optical filter IF can be disposed between the eighth lens 280 and the image sensor IMG. The image sensor IMG can provide a surface on which light refracted by the first lens 210 through the eighth lens 280 is formed. One surface of the image sensor IMG can be substantially the same size as the imaging surface. For example, a diagonal length (2IMGHT) of the imaging surface refers to a diagonal length of the image sensor IMG, and a height of the imaging surface can refer to a distance from a center of an optical axis of the image sensor IMG to an edge. The stop ST can be disposed between the second lens 220 and the third lens 230.

[0113] Table 3 and Table 4 list lens properties and aspherical values of the imaging lens system 200. Figure 4 is an aberration curve of the imaging lens system 200 of the above configuration.

[0114] Table 3

[0115]

[0116]

[0117] Table 4

[0118] Face number K A B C D E F G H J S1 -0.977501 -0.003935 0.03566 -0.06648 0.07812 -0.05719 0.02357 -0.001832 -0.003927 0.002605 S2 24.256772 -0.01734 0.02382 -0.04735 0.09105 -0.1273 0.1247 -0.08725 0.04424 -0.01632 S3 16.447043 -0.04114 0.1252 -0.3314 0.5847 -0.6813 0.5346 -0.2841 0.09972 -0.02093 S4 2.4777825 -0.02548 0.1177 -0.3338 0.515 -0.3284 -0.2047 0.6032 -0.5729 0.3107 S5 0 0.0001756 -0.08569 0.3416 -0.9226 1.758 -2.428 2.459 -1.829 0.9952 S6 56.350823 -0.01711 0.02414 -0.09787 0.228 -0.3404 0.3182 -0.173 0.03554 0.01898 S7 98.884228 -0.03447 0.2124 -1.059 3.234 -6.491 8.929 -8.669 6.038 -3.03 S8 -99.00005 -0.03892 0.08133 -0.01505 -0.6266 2.045 -3.46 3.728 -2.737 1.404 S9 0 -0.03305 0.006005 -0.09955 0.3424 -0.6687 0.8536 -0.7539 0.4727 -0.2123 S10 0 -0.04115 0.02906 -0.06185 0.089 -0.09332 0.07136 -0.03976 0.01616 -0.004776 S11 0 -0.08603 0.09214 -0.08082 0.05511 -0.03092 0.01465 -0.005795 0.001809 -0.00042 S12 -39.38114 -0.1047 0.1 -0.07676 0.0443 -0.01861 0.005745 -0.001373 0.0002715 -4.57E-05 S13 -7.365153 -0.02249 0.01129 -0.00247 -0.002451 0.00202 -0.000725 0.0001571 -2.25E-05 2.215E-06 S14 23.383791 0.01202 -0.007542 0.007938 -0.006811 0.003202 -0.000929 0.0001797 -2.41E-05 2.286E-06 S15 -1.492134 -0.07336 0.04525 -0.0173 0.003788 -0.000412 2.16E-06 5.752E-06 -8.72E-07 7.101E-08 S16 -19.10332 -0.06043 0.03583 -0.01475 0.004065 -0.000781 0.0001088 -1.12E-05 8.63E-07 -4.94E-08

[0119] A third example of an imaging lens system will be described with reference to Figure 5 A third example of an imaging lens system will be described with reference to

[0120] The imaging lens system 300 can include a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, a seventh lens 370, and an eighth lens 380.

[0121] The first lens 310 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 320 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 330 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 340 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 350 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the fifth lens 350. The sixth lens 360 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the sixth lens 360. The seventh lens 370 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the seventh lens 370. The eighth lens 380 can have a negative refractive power, and can have a concave object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the eighth lens 380.

[0122] The imaging lens system 300 can further include an optical filter IF, an image sensor IMG, and a stop ST. The optical filter IF can be disposed between the eighth lens 380 and the image sensor IMG. The image sensor IMG can provide a surface on which light refracted by the first lens 310 through the eighth lens 380 is formed. One surface of the image sensor IMG can be substantially the same size as the imaging surface. For example, a diagonal length (2IMGHT) of the imaging surface refers to a diagonal length of the image sensor IMG, and a height of the imaging surface can refer to a distance from a center of an optical axis of the image sensor IMG to an edge. The stop ST can be disposed between the second lens 320 and the third lens 330.

[0123] Table 5 and Table 6 list lens properties and aspherical values of the imaging lens system 300. Figure 6 is an aberration curve of the imaging lens system 300 of the above-described configuration.

[0124] Table 5

[0125]

[0126]

[0127] Table 6

[0128] Face number K A B C D E F G H J S1 -1.021828 -0.01896 0.1021 -0.2305 0.3375 -0.3375 0.239 -0.1221 0.04541 -0.01224 S2 27.483091 -0.02125 0.02647 -0.04209 0.08433 -0.1286 0.1344 -0.09851 0.05187 -0.01979 S3 16.571645 -0.0269 0.02934 -0.02785 0.005501 0.06759 -0.1621 0.1991 -0.1548 0.08107 S4 2.329664 -0.008104 0.01857 -0.07846 0.2349 -0.4188 0.4574 -0.2903 0.0682 0.04808 S5 0 0.03542 -0.3975 1.734 -4.822 9.088 -12.06 11.52 -8.02 4.072 S6 95.620843 -0.04713 0.2007 -0.809 2.045 -3.463 4.085 -3.434 2.081 -0.9096 S7 92.803604 -0.04517 0.2372 -1.015 2.742 -4.991 6.357 -5.802 3.841 -1.847 S8 19.623148 -0.0422 0.1464 -0.5006 1.076 -1.54 1.523 -1.066 0.5322 -0.1886 S9 0 -0.03346 0.01336 -0.1054 0.32 -0.589 0.7273 -0.6276 0.385 -0.1686 S10 0 -0.03637 0.04988 -0.1559 0.2794 -0.3299 0.2711 -0.1595 0.06818 -0.02119 S11 0 -0.05656 0.03784 -0.02001 0.003531 0.003559 -0.003956 0.00219 -0.000802 0.000204 S12 -37.93685 -0.06085 0.01424 0.01542 -0.02468 0.01805 -0.00854 0.002828 -0.000672 0.0001149 S13 -9.92841 -0.006148 -0.01069 0.01178 -0.008163 0.003492 -0.000994 0.000197 -2.78E-05 2.817E-06 S14 46.8868 0.02276 -0.0168 0.01054 -0.005761 0.002195 -0.000576 0.0001064 -1.41E-05 1.345E-06 S15 -1.893815 -0.07156 0.03583 -0.01332 0.003704 -0.000717 9.637E-05 -9.14E-06 6.184E-07 -2.98E-08 S16 -25.29874 -0.04909 0.02346 -0.008608 0.002275 -0.000431 5.922E-05 -5.95E-06 4.389E-07 -2.37E-08

[0129] A fourth example of an imaging lens system will be described with reference to Figure 7 A fourth example of an imaging lens system will be described with reference to

[0130] The imaging lens system 400 can include a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, a seventh lens 470, and an eighth lens 480.

[0131] The first lens 410 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 420 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 430 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 440 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 450 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the fifth lens 450. The sixth lens 460 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the sixth lens 460. The seventh lens 470 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the seventh lens 470. The eighth lens 480 can have a negative refractive power, and can have a concave object side surface and a concave image side surface. A reverse curve point can be formed on at least one of the object side surface and the image side surface of the eighth lens 480.

[0132] The imaging lens system 400 can further include an optical filter IF, an image sensor IMG, and a stop ST. The optical filter IF can be disposed between the eighth lens 480 and the image sensor IMG. The image sensor IMG can provide a surface on which light refracted by the first lens 410 through the eighth lens 480 is formed. One surface of the image sensor IMG can be substantially the same size as the imaging surface. For example, a diagonal length (2IMGHT) of the imaging surface refers to a diagonal length of the image sensor IMG, and a height of the imaging surface can refer to a distance from a center of an optical axis of the image sensor IMG to an edge. The stop ST can be disposed between the second lens 420 and the third lens 430.

[0133] Table 7 and Table 8 list lens properties and aspherical values of the imaging lens system 400. Figure 8 is an aberration curve of the imaging lens system 400 of the above configuration.

[0134] Table 7

[0135]

[0136] Table 8

[0137]

[0138]

[0139] A fifth example of an imaging lens system will be described with reference to Figure 9 A fifth example of an imaging lens system will be described with reference to

[0140] The imaging lens system 500 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.

[0141] The first lens 510 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. The second lens 520 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The third lens 530 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The fourth lens 540 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. The fifth lens 550 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. An inflection point can be formed on at least one of the object side surface and the image side surface of the fifth lens 550. The sixth lens 560 can have a negative refractive power, and can have a convex object side surface and a concave image side surface. An inflection point can be formed on at least one of the object side surface and the image side surface of the sixth lens 560. The seventh lens 570 can have a positive refractive power, and can have a convex object side surface and a concave image side surface. An inflection point can be formed on at least one of the object side surface and the image side surface of the seventh lens 570. The eighth lens 580 can have a negative refractive power, and can have a concave object side surface and a concave image side surface. An inflection point can be formed on at least one of the object side surface and the image side surface of the eighth lens 580.

[0142] The imaging lens system 500 can further include an optical filter IF, an image sensor IMG, and a stop ST. The optical filter IF can be disposed between the eighth lens 580 and the image sensor IMG. The image sensor IMG can provide a surface on which light refracted by the first lens 510 to the eighth lens 580 is formed. One surface of the image sensor IMG can be substantially the same size as the imaging surface. For example, a diagonal length (2IMGHT) of the imaging surface refers to a diagonal length of the image sensor IMG, and a height of the imaging surface can refer to a distance from a center of an optical axis of the image sensor IMG to an edge. The stop ST can be disposed between the second lens 520 and the third lens 530.

[0143] Tables 9 and 10 list lens properties and aspherical values of the imaging lens system 500. Figure 10 is an aberration curve of the imaging lens system 500 of the above configuration.

[0144] Table 9

[0145]

[0146] Table 10

[0147] Face number K A B C D E F G H J S1 -1.028837 -0.02409 0.1446 -0.3787 0.6314 -0.7099 0.5594 -0.3161 0.1294 -0.03841 S2 27.139418 -0.01912 0.01984 -0.01858 0.03317 -0.06354 0.0825 -0.07178 0.04322 -0.01831 S3 16.56626 -0.03611 0.08325 -0.1934 0.3467 -0.4275 0.3499 -0.18 0.04606 0.005663 S4 2.3619195 -0.006635 -0.02015 0.1695 -0.6002 1.364 -2.14 2.391 -1.928 1.124 S5 0 0.03964 -0.4617 2.104 -6.062 11.76 -16 15.64 -11.12 5.753 S6 98.932938 -0.05194 0.2269 -0.8855 2.193 -3.673 4.319 -3.642 2.225 -0.9845 S7 92.330151 -0.03483 0.1489 -0.6154 1.616 -2.873 3.577 -3.193 2.069 -0.9745 S8 -98.98639 -0.0416 0.134 -0.4795 1.094 -1.666 1.759 -1.327 0.7252 -0.2882 S9 0 -0.03919 0.02504 -0.1109 0.3044 -0.5401 0.652 -0.5516 0.3318 -0.1424 S10 0 -0.03933 0.05215 -0.1519 0.2678 -0.3165 0.2629 -0.1574 0.06872 -0.0219 S11 0 -0.06085 0.0609 -0.05644 0.0367 -0.01688 0.005064 -0.000733 -0.0001 8.014E-05 S12 -36.84334 -0.08749 0.07584 -0.05801 0.03358 -0.01451 0.004584 -0.001033 0.0001598 -1.57E-05 S13 -9.956325 -0.01164 6.404E-05 0.000979 -0.002315 0.001509 -0.000532 0.0001191 -1.81E-05 1.903E-06 S14 -84.33771 0.02575 -0.01685 0.007841 -0.00402 0.001651 -0.000474 9.442E-05 -1.33E-05 1.33E-06 S15 -1.549727 -0.06796 0.03522 -0.01412 0.004139 -0.000819 0.0001098 -1.01E-05 6.502E-07 -2.85E-08 S16 -23.9777 -0.04939 0.02417 -0.009403 0.002602 -0.000508 0.0000709 -7.18E-06 5.316E-07 -2.87E-08

[0148] Tables 11 and 12 list optical property values and values of conditional expressions of the imaging lens systems of the first to fifth examples. In Table 11, BFL refers to a distance from an image side surface of the eighth lens to the imaging surface.

[0149] Table 11

[0150]

[0151]

[0152] Table 12

[0153]

[0154] According to the above examples, the performance of a small camera can be improved.

[0155] While the present disclosure includes specific examples, it will be apparent to one skilled in the art, after an understanding of the disclosure herein, that various changes in form and details can be made without departing from the spirit and scope of the claims and their equivalents. The examples described herein should be understood to be descriptive, not limiting. Descriptions of features or aspects in each example should be understood to apply to similar features or aspects in other examples. If the described technology is performed in a different order, and / or if the described systems, architectures, devices, or circuits are combined or separated, or replaced or supplemented by other components or their equivalents, then appropriate results can still be achieved. Thus, the scope of the present disclosure is not limited by the specific implementations described herein, but only by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims

1. Imaging lens system, comprising: A first lens having a positive refractive power; A second lens having a negative refractive power; 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 negative refractive power; A seventh lens having a positive refractive power; And An eighth lens having a negative refractive power and having a concave object side surface in the paraxial region, wherein, the first lens to the eighth lens are arranged in sequence from the object side to the imaging surface, wherein, the imaging lens system has a total of eight lenses, wherein, -1.4 < f1 / f8 < -0.4, 1.06 < f / IMGHT < 1.12 and -5.0 < f6 / f7 < -2.0, wherein, f1 is the focal length of the first lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, f8 is the focal length of the eighth lens, f is the focal length of the imaging lens system, and IMGHT is half of the diagonal length of the imaging surface.

2. The imaging lens system according to claim 1, wherein, The first lens has a convex object side surface.

3. The imaging lens system according to claim 1, wherein, The second lens has a convex object side surface.

4. The imaging lens system according to claim 1, wherein, The third lens has a convex object side surface.

5. The imaging lens system according to claim 1, wherein, The fourth lens has a convex object side surface.

6. The imaging lens system according to claim 1, wherein, The fifth lens has a convex object side surface.

7. The imaging lens system according to claim 1, wherein, The sixth lens has a convex object side surface.

8. The imaging lens system according to claim 1, wherein, The seventh lens has a convex object side surface.

9. The imaging lens system according to claim 1, wherein, The eighth lens has a concave object side surface.

10. Imaging lens system, comprising: A first lens having a positive refractive power; A second lens having a negative refractive power; A third lens having a negative refractive power; A fourth lens having a positive refractive power; A fifth lens having a negative refractive power; A sixth lens having a negative refractive power; A seventh lens having a positive refractive power; And An eighth lens having a negative refractive power and having a concave object side surface in the paraxial region, wherein, the first lens to the eighth lens are arranged in sequence from the object side to the imaging surface, wherein, the imaging lens system has a total of eight lenses, and wherein, -1.4 < f1 / f8 < -0.4 and 1.06 < f / IMGHT < 1.12, wherein, f1 is the focal length of the first lens, f8 is the focal length of the eighth lens, f is the focal length of the imaging lens system, and IMGHT is half of the diagonal length of the imaging surface.

11. The imaging lens system according to claim 10, wherein, The imaging lens system f-number 1.7 or smaller.

12. The imaging lens system according to claim 10, wherein, TTL / IMGHT < 1.5, wherein, TTL is the distance from the object side surface of the first lens to the imaging surface.

13. The imaging lens system according to claim 10, wherein, 0.5 < f1 / f < 1.

0.

14. The imaging lens system according to claim 10, wherein, 0.4 < f1 / f7 < 1.2, wherein, f7 is the focal length of the seventh lens.

15. The imaging lens system according to claim 10, wherein, 2.0 < (R5 + R6) / (R5 - R6) < 4.0, wherein, R5 is the radius of curvature of the object side surface of the third lens, and R6 is the radius of curvature of the image side surface of the third lens.

Images