Imaging lens system

Abstract

The imaging lens system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially arranged from the object side. The third lens has a refractive index temperature coefficient of 2.2 to 3.5 [10-6 / °C], and 0 < f34 * 0.8 < f, where f is the focal length of the imaging lens system, and f34 is the combined focal length of the third lens and the fourth lens.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10 - 2021 - 0103230, filed with the Korean Intellectual Property Office on August 5, 2021, the entire disclosure of which is incorporated herein by reference for all purposes. Technical field

[0003] The following description relates to an imaging lens system that is configured to achieve constant optical performance regardless of changes in the temperature of the surrounding environment. Background art

[0004] Since early small - sized surveillance cameras were configured to image obstacles near vehicles, such cameras not only had relatively low resolution but also had a wide range of resolution variations according to temperature changes from - 40°C to 80°C. However, due to the growing demand for autonomous driving functions of vehicles, there is a need to develop surveillance cameras that have high resolution and can achieve certain optical characteristics even under harsh temperature conditions. Summary of the invention

[0005] The Summary of the Invention section is provided to introduce, in a brief form, selections of inventive concepts, which will be further described in the Detailed Description section below. The Summary of the Invention section is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to assist in determining the scope of the claimed subject matter.

[0006] In one general aspect, an imaging lens system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially arranged from the object side. The third lens has a refractive index temperature coefficient of 2.2×10 -6 / °C to 3.5×10 -6 / °C, and 0 < f34 * 0.8 < f, where f is the focal length of the imaging lens system and f34 is the combined focal length of the third lens and the fourth lens.

[0007] The first lens, the second lens, and the third lens may be formed of materials different from those of the fourth lens, the fifth lens, the sixth lens, and the seventh lens.

[0008] The imaging lens system may satisfy 35 < V2 / Nd2 < 45, where V2 is the Abbe number of the second lens and Nd2 is the refractive index of the second lens.

[0009] The imaging lens system may satisfy 20 < V3 / Nd3 < 30, where V3 is the Abbe number of the third lens and Nd3 is the refractive index of the third lens.

[0010] The imaging lens system can satisfy 10 < V5 / Nd5 < 20, where V5 is the Abbe number of the fifth lens, and Nd5 is the refractive index of the fifth lens.

[0011] The imaging lens system can satisfy 30 < V6 / Nd6 < 40, where V6 is the Abbe number of the sixth lens, and Nd6 is the refractive index of the sixth lens.

[0012] The imaging lens system can satisfy 27 < Vmin13 / Ndmin13 < 37, where Vmin13 is the minimum value among the Abbe numbers of the first lens, the second lens, and the third lens, and Ndmin13 is the minimum value among the refractive indices of the first lens, the second lens, and the third lens.

[0013] The imaging lens system can satisfy 30 < Vmax47 / Ndmax47 < 35, where Vmax47 is the maximum value among the Abbe numbers of the fourth lens, the fifth lens, the sixth lens, and the seventh lens, and Ndmax47 is the maximum value among the refractive indices of the fourth lens, the fifth lens, the sixth lens, and the seventh lens.

[0014] The imaging lens system can satisfy 0.4 < f / f3 < 0.9, where f3 is the focal length of the third lens.

[0015] In another general aspect, the imaging lens system includes: a first lens having a negative refractive power; a second lens having a concave object side; a third lens having a convex object side; a fourth lens having a positive refractive power; a fifth lens having a concave object side; a sixth lens having a convex object side; and a seventh lens having a negative refractive power. The imaging lens system satisfies 0 < f34 * 0.8 < f, where f is the focal length of the imaging lens system, and f34 is the combined focal length of the third lens and the fourth lens.

[0016] The first lens may have a convex object side.

[0017] The first lens may have a refractive index temperature coefficient of 2.5×10 -6 / ℃ to 4.5×10 -6 / ℃.

[0018] The second lens may have a refractive index temperature coefficient of 1.0×10 -6 / ℃ to 2.5×10 -6 / ℃.

[0019] The fourth lens may have a refractive index temperature coefficient of -110×10 -6 / ℃ to -80×10 -6 / ℃.

[0020] The fifth lens may have a concave image side.

[0021] The imaging lens system may satisfy 1.1 < Nd3 / Nd4 < 1.2, where Nd3 is the refractive index of the third lens and Nd4 is the refractive index of the fourth lens.

[0022] Other features and aspects will become apparent in light of the appended claims, the drawings, and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a block diagram of an imaging lens system according to a first embodiment of the present disclosure;

[0024] Figure 2 is Figure 1 the MTF curve of the imaging lens system shown;

[0025] Figure 3 is a graph showing Figure 1 the back focal length (BFL) of the imaging lens system shown as a function of temperature;

[0026] Figure 4 is a block diagram of an imaging lens system according to a second embodiment of the present disclosure;

[0027] Figure 5 is Figure 4 the MTF curve of the imaging lens system shown;

[0028] Figure 6 is a graph showing Figure 4 the BFL of the imaging lens system shown as a function of temperature;

[0029] Figure 7 is a block diagram of an imaging lens system according to a third embodiment of the present disclosure;

[0030] Figure 8 is Figure 7 the MTF curve of the imaging lens system shown; and

[0031] Fig. 9 is a graph showing Figure 7 the BTF of the imaging lens system shown as a function of temperature.

[0032] Throughout the drawings and the detailed description, like reference numerals refer to like elements. For clarity, illustration, and convenience, the drawings may not be to scale, and the relative dimensions, proportions, and depictions of elements in the drawings may be exaggerated. DETAILED DESCRIPTION

[0033] The following specific embodiments are provided to help the reader gain a comprehensive understanding of the methods, devices and / or systems described herein. However, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent to those of ordinary skill in the art. The order of operations described herein is merely an example, and except for operations that must occur in a particular order, it is not limited to the order set forth herein, but may be changed, which will be apparent to those of ordinary skill in the art. In addition, for greater clarity and brevity, descriptions of functions and structures well known to those of ordinary skill in the art may be omitted.

[0034] The features described herein may be implemented in different forms and should not be understood as being limited to the examples described herein. Rather, the examples described herein have been provided so that this disclosure will be thorough and complete and will fully convey the scope of this disclosure to those of ordinary skill in the art.

[0035] It should be noted that in this document, use of the word "may" with respect to an example or implementation (e.g., with respect to what an example or implementation may include or implement) means that there is at least one example or implementation that includes or implements such features, and all examples and implementations are not limited thereto.

[0036] Throughout the specification, when an element such as a layer, a region, or a substrate is described as being “on,” “connected to,” or “coupled to” another element, the element may be directly “on,” “connected to,” or “coupled to” the other element, or one or more other elements may be present between the element and the other element. Conversely, when an element is described as being “directly on,” “directly connected to,” or “directly coupled to” another element, no other elements may be present between the element and the other element.

[0037] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0038] Although terms such as "first", "second" and "third" may be used herein to describe various members, components, regions, layers or portions, these members, components, regions, layers or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer or portion from another member, component, region, layer or portion. Therefore, without departing from the teachings of the examples described herein, the first member, first component, first region, first layer or first portion mentioned in these examples may also be referred to as the second member, second component, second region, second layer or second portion.

[0039] Spatially relative terms such as "above", "higher", "below", and "lower" may be used herein for descriptive convenience to describe the relationship of one element relative to another element as shown in the accompanying drawings. In addition to covering the orientations depicted in the accompanying drawings, these spatially relative terms are intended to also cover different orientations of the device in use or operation. For example, if the device in the accompanying drawings is flipped, an element described as being "above" or "higher" relative to another element will be "below" or "lower" relative to the other element. Therefore, depending on the spatial orientation of the device, the term "above" covers both orientations of "above" and "below". The device may also be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially relative terms used herein should be interpreted accordingly.

[0040] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the articles "a", "an" and "the" are intended to include plural forms as well. The words "include", "comprise" and "have" indicate the presence of the features, numbers, operations, components, elements and / or combinations thereof, but do not exclude the presence or addition of one or more other features, numbers, operations, components, elements and / or combinations thereof.

[0041] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0042] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have multiple configurations, other configurations that will be apparent after understanding the disclosure of the present application are also feasible.

[0043] The imaging lens system includes a plurality of lenses arranged along an optical axis. The plurality of lenses may be spaced apart from each other by a predetermined distance along the optical axis.

[0044] For example, the imaging lens system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, which are arranged in sequence along the optical axis from the object side of the imaging lens system toward the imaging surface of the imaging lens system, wherein the first lens is closest to the object side of the imaging lens system and the seventh lens is closest to the imaging surface.

[0045] In each lens, the object-side or first face is the face of the lens closest to the object side of the imaging lens system, and the image-side or second face is the face of the lens closest to the imaging plane.

[0046] Unless otherwise specified, the shape of the lens surface refers to the shape of the paraxial region of the lens surface. The paraxial region of the lens surface is the central portion of the lens surface that surrounds and includes the optical axis of the lens surface, in which the light incident on the lens surface forms a small angle θ with the optical axis, and the approximations of sinθ≈θ, tanθ≈θ, and cosθ≈1 are valid.

[0047] For example, the statement that the object side surface of the lens is convex means that at least the paraxial region of the object side surface of the lens is convex, and the statement that the image side surface of the lens is concave means that at least the paraxial region of the image side surface of the lens is concave. Therefore, even if the object side surface of the lens can be described as convex, the entire object side surface of the lens may not be convex, and the peripheral region of the object side surface of the lens may be concave. In addition, even if the image side surface of the lens can be described as concave, the entire image side surface of the lens may not be concave, and the peripheral region of the image side surface of the lens may be convex.

[0048] At least one of the first to seventh lenses of the imaging lens system may have at least one aspherical surface.

[0049] In addition to the first to seventh lenses, the imaging lens system may further include other elements.

[0050] The imaging lens system may further include at least one aperture stop disposed before the first lens, or between any two adjacent lenses from the first lens to the seventh lens, or between the seventh lens and the imaging surface. The imaging lens system may include two or more aperture stops disposed at different positions.

[0051] The imaging lens system may further include an image sensor having an imaging surface disposed at an imaging plane of the imaging lens system. The image sensor converts an image of an object formed on an effective imaging area of ​​the imaging surface by the lens of the imaging lens system into an electrical signal.

[0052] The imaging lens system may further include an infrared blocking filter for blocking infrared light, hereinafter referred to as a filter. The filter may be disposed between the seventh lens and the imaging plane.

[0053] The imaging lens system may further include at least one reflective member having a reflective surface that changes the direction of the optical path in the imaging lens system. For example, the reflective member may be a prism or a reflective mirror.

[0054] For example, the reflective member may be provided in the optical path on the object side of the first lens, between any two lenses among the second to seventh lenses, or on the image side of the seventh lens.

[0055] For example, the imaging lens system may further include a first reflective member disposed in the optical path between the object side of the imaging lens system and the object side surface of the first lens. Therefore, the first lens may be the lens disposed closest to the first reflective member among the first to seventh lenses.

[0056] In addition, the imaging lens system may further include a second reflective member disposed in the optical path between the image side surface and the imaging surface of the seventh lens. Therefore, the seventh lens may be the lens disposed closest to the second reflective member among the first to seventh lenses.

[0057] TTL is the distance from the object side of the first lens to the image plane along the optical axis.

[0058] SL is the distance along the optical axis from the aperture of the imaging lens system to the imaging plane.

[0059] BFL is the distance from the image side surface of the seventh lens to the image forming plane along the optical axis.

[0060] PTTL is the distance from the reflection surface of the first reflection member to the imaging plane along the optical axis.

[0061] ImgH is the maximum effective image height of the imaging lens system and is equal to half the diagonal length of the effective imaging area of ​​the imaging surface of the image sensor.

[0062] f is the focal length of the imaging lens system, and f1, f2, f3, f4, f5, f6, and f7 are the focal lengths of the first lens to the seventh lens, respectively.

[0063] FOV is the viewing angle of the imaging lens system.

[0064] Fno is the f-number of the imaging lens system, and is equal to the focal length f of the imaging lens system divided by the entrance pupil diameter of the imaging lens system.

[0065] DTn is the refractive index temperature coefficient of the lens of the imaging lens system.

[0066] The effective semi-aperture of the lens surface is the radius of the portion of the lens surface through which light actually passes, and is not necessarily the radius of the outer edge of the lens surface. In other words, the effective semi-aperture of the lens surface is the distance between the optical axis and the marginal ray of light passing through the lens surface in a direction perpendicular to the optical axis of the lens surface. The object side of the lens and the image side of the lens may have different effective semi-apertures.

[0067] The radius of curvature of the lens surface, the thicknesses of the lens and other elements, the distances between two adjacent ones of the lens and other elements, the focal length f of the imaging lens system, the respective focal lengths f1, f2, f3, f4, f5, f6, and f7 of the first to seventh lenses, TTL, SL, BFL, PTTL, and ImgH are expressed in millimeters (mm), although other measurement units may also be used. FOV is expressed in degrees. Fno, the refractive index of the lens, and the Abbe number of the lens are dimensionless quantities.

[0068] The thicknesses of the lens and other elements, the distances between two adjacent ones of the lens and other elements, TTL, SL, BFL, and PTTL are measured along the optical axis of the imaging lens system.

[0069] The imaging lens system according to various examples includes a plurality of lenses. For example, the imaging lens system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged in order from the object side.

[0070] The imaging lens system may include a lens having a predetermined refractive index temperature coefficient. For example, the third lens may have a refractive index temperature coefficient of 2.2×10 -6 / °C to 3.5×10 -6 / °C. The imaging lens system may be configured to satisfy a predetermined conditional expression. For example, the imaging lens system may satisfy the conditional expression: 0 < f34 * 0.8 < f. In the conditional expression, f is the focal length of the imaging lens system, and f34 is the combined focal length of the third lens and the fourth lens. The imaging lens system according to the example includes a plurality of lenses. For example, the imaging lens system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially arranged from the object side. The imaging lens system may include a lens having a predetermined refractive power. For example, the first lens and the seventh lens may have negative refractive powers, and the fourth lens may have a positive refractive power. In addition, the imaging lens system according to the present embodiment may include a lens having a predetermined shape. For example, the object side surface of the second lens and the object side surface of the fifth lens may be concave. As another example, the object side surface of the third lens and the object side surface of the sixth lens may be convex. In addition, in the imaging lens system, the conditional expression: 0 < f34 * 0.8 < f may be satisfied.

[0071] The imaging lens system according to the example may be configured as a combination of an imaging lens system according to one example and an imaging lens system according to another example. As an example, the imaging lens system may be configured to include some features of an imaging lens system according to one example and some features of an imaging lens system according to another example.

[0072] As an example, the imaging lens system includes a first lens to a seventh lens arranged in order from the object side, and may include a first lens having a negative refractive power and a lens having a 2.2×10 -6 / ℃ to 3.5×10 -6 / ℃ refractive index temperature coefficient of the third lens.

[0073] As another example, the imaging lens system includes a first lens to a seventh lens arranged in order from the object side, and may include a second lens having a concave object side surface and a second lens having a 2.2×10 -6 / ℃ to 3.5×10 -6 / ℃ refractive index temperature coefficient of the third lens.

[0074] If desired, the imaging lens system may include one or more lenses having the following characteristics. As an example, the imaging lens system may include one or more of the first to seventh lenses having the following characteristics. As another example, the imaging lens system may include two or more of the first to seventh lenses having the following characteristics. However, the configuration of the imaging lens system is not limited thereto.

[0075] Hereinafter, characteristics of the first to seventh lenses will be described.

[0076] The first lens has a refractive power. One surface of the first lens may be convex. For example, the first lens has a convex object side surface. The first lens includes a spherical surface or an aspherical surface. For example, both surfaces of the first lens may be spherical. The first lens may be formed of a material having high light transmittance and excellent processability. For example, the first lens may be formed of a glass material. The first lens has a predetermined refractive index. For example, the refractive index of the first lens may be 1.75 or greater.

[0077] The second lens has a refractive power. One surface of the second lens may be convex. For example, the second lens may have a convex image side surface. The second lens includes a spherical surface. For example, both surfaces of the second lens may be spherical. The second lens may be formed of a material having high light transmittance and excellent processability. For example, the second lens may be formed of a glass material. The second lens has a predetermined refractive index. For example, the refractive index of the second lens may be less than 1.53.

[0078] The third lens has a refractive power. One surface of the third lens may be convex. For example, the third lens may have a convex image side surface. The third lens includes a spherical surface. For example, both surfaces of the third lens may be spherical. The third lens may be formed of a material having high light transmittance and excellent processability. For example, the third lens may be formed of a glass material. The third lens has a refractive index greater than the refractive index of the first lens and the refractive index of the second lens. For example, the refractive index of the third lens may be 1.78 or greater.

[0079] The fourth lens has a refractive power. One surface of the fourth lens may be convex. For example, the fourth lens may have a convex object side surface. The fourth lens includes an aspherical surface. For example, both surfaces of the fourth lens may be aspherical. The fourth lens may be formed of a material having high light transmittance and excellent processability. For example, the fourth lens may be formed of a plastic material. The fourth lens has a predetermined refractive index. For example, the refractive index of the fourth lens may be less than 1.56.

[0080] The fifth lens has a refractive power. One surface of the fifth lens may be concave. For example, the fifth lens may have a concave image side surface. The fifth lens includes an aspherical surface. For example, both surfaces of the fifth lens may be aspherical. The fifth lens may be formed of a material having high light transmittance and excellent processability. For example, the fifth lens may be formed of a plastic material. The fifth lens has a predetermined refractive index. For example, the refractive index of the fifth lens may be 1.6 or greater.

[0081] The sixth lens has a refractive power. One surface of the sixth lens may be convex. For example, the sixth lens may have a convex image side surface. The sixth lens includes an aspherical surface. For example, both surfaces of the sixth lens may be aspherical. The sixth lens may be formed of a material having high light transmittance and excellent processability. For example, the sixth lens may be formed of a plastic material. The sixth lens has a refractive index substantially similar to that of the fourth lens. For example, the refractive index of the sixth lens may be less than 1.56.

[0082] The seventh lens has a refractive power. One surface of the seventh lens may be concave. For example, the seventh lens may have a concave image side surface. The seventh lens includes an aspherical surface. For example, both surfaces of the seventh lens may be aspherical. The seventh lens may be formed of a material having high light transmittance and excellent processability. For example, the seventh lens may be formed of a plastic material. The seventh lens has a refractive index substantially similar to that of the sixth lens. For example, the refractive index of the seventh lens may be less than 1.56.

[0083] The aspherical lens constituting the imaging lens system can be expressed by Equation 1 below.

[0084] Equation 1:

[0085]

[0086] In Equation 1, c is the inverse of the radius of curvature of the lens, k is the cone constant, r is the distance from any point on the aspheric surface to the optical axis, A, B, C, D, E, F, F, G are aspheric constants, and Z (or SAG) is the height from any point on the aspheric surface to the vertex of the aspheric surface in the direction of the optical axis.

[0087] The imaging lens system may include lenses of different materials. For example, the first to third lenses may be formed of a material different from that of the fourth to seventh lenses. As a specific example, the first to third lenses may be formed of a glass material having a small thermal expansion coefficient due to external impact and temperature change, and the fourth to seventh lenses may be formed of a plastic material that is easy to process.

[0088] The imaging lens system may include a lens having a predetermined refractive index temperature coefficient. As an example, the imaging lens system may include a lens having a 2.5×10 -6 / ℃ to 4.5×10 -6 / °C. As another example, the imaging lens system may include a first lens having a refractive index temperature coefficient of 1.0×10 -6 / ℃ to 2.5×10 -6 As another example, the imaging lens system may include a second lens having a refractive index temperature coefficient of -110×10 -6 / ℃ to -80×10 -6 The fourth lens has a refractive index temperature coefficient of / °C.

[0089] The imaging lens system includes an aperture, an imaging surface and a filter. In addition, the imaging lens system may also include a cover glass.

[0090] As an example, the aperture may be disposed between the third lens and the fourth lens. As another example, the aperture may be disposed on the image side of a lens having positive refractive power, or may be disposed between a lens having positive refractive power and a lens having positive refractive power. An imaging plane may be formed at a point where the light refracted by the first lens to the seventh lens forms an image. The imaging plane may be formed by an image sensor. For example, the imaging plane may be formed on the surface of the image sensor or inside the image sensor. An optical filter may be disposed between the seventh lens and the imaging plane. The optical filter may block some wavelengths of light. For example, the optical filter may block infrared wavelengths of light. A cover glass may be disposed between the optical filter and the imaging plane.

[0091] The imaging lens system may satisfy one or more of the following conditional expressions:

[0092] 20 <V1 / Nd1<30

[0093] 35 <V2 / Nd2<45

[0094] 20 <V3 / Nd3<30

[0095] 30 <V4 / Nd4<40

[0096] 10 <V5 / Nd5<20

[0097] 30 <V6 / Nd6<40

[0098] 30 <V7 / Nd7<40

[0099] 27 <Vmin13 / Ndmin13<37

[0100] 30 <Vmax47 / Ndmax47<35

[0101] 0.4 <f / f3<0.9

[0102] 1.1 <Nd3 / Nd4<1.2

[0103] In the conditional expressions, V1 is the Abbe number of the first lens, Nd1 is the refractive index of the first lens, V2 is the Abbe number of the second lens, Nd2 is the refractive index of the second lens, V3 is the Abbe number of the third lens, Nd3 is the refractive index of the third lens, V4 is the Abbe number of the fourth lens, ND4 is the refractive index of the fourth lens, V5 is the Abbe number of the fifth lens, Nd5 is the refractive index of the fifth lens, and V6 is the Abbe number of the sixth lens, Nd6 is the refractive index of the sixth lens, V7 is the Abbe number of the seventh lens, Nd7 is the refractive index of the seventh lens, and Vmin13 is the minimum value among the Abbe numbers of the first lens to the third lens, Ndmin13 is the minimum value among the refractive indices of the first lens to the third lens, Vmax47 is the maximum value among the Abbe numbers of the fourth lens to the seventh lens, and Ndmax47 is the maximum value among the refractive indices of the fourth lens to the seventh lens, f is the focal length of the imaging lens system, and f3 is the focal length of the third lens.

[0104] Hereinafter, various examples will be described in detail based on the attached exemplary drawings.

[0105] First, refer to Figure 1 An imaging lens system according to a first example is described.

[0106] The imaging lens system 100 includes a first lens 110 , a second lens 120 , a third lens 130 , a fourth lens 140 , a fifth lens 150 , a sixth lens 160 , and a seventh lens 170 .

[0107] The first lens 110 has negative refractive power and has a convex object side surface and a concave image side surface. The second lens 120 has negative refractive power and has a concave object side surface and a convex image side surface. The third lens 130 has positive refractive power and has a convex object side surface and a convex image side surface. The fourth lens 140 has positive refractive power and has a convex object side surface and a convex image side surface. The fifth lens 150 has negative refractive power and has a concave object side surface and a concave image side surface. The sixth lens 160 has positive refractive power and has a convex object side surface and a convex image side surface. The seventh lens 170 has negative refractive power and has a convex object side surface and a concave image side surface.

[0108] The imaging lens system 100 may further include a stop ST, a filter IF, and an imaging surface IP. The stop ST may be disposed between the third lens 130 and the fourth lens 140. The imaging surface IP may be formed in the image sensor IS, and the filter IF may be disposed between the seventh lens 170 and the imaging surface IP. In addition, the cover glass may be formed integrally with the image sensor IS.

[0109] Figure 2 and Figure 3 The MTF characteristics of the imaging lens system 100 and the amount of change in the back focus (ΔBFL: μm) according to the temperature are shown.

[0110] Tables 1 and 2 show lens characteristics and aspherical values ​​of the imaging lens system 100 .

[0111] Table 1

[0112]

[0113]

[0114] Table 2

[0115] Face number K A B C D S8 7.0642.E-02 -2.4369.E-03 -4.6737.E-04 -1.1169.E-05 -2.0495.E-05 S9 -7.5150.E+00 1.1083.E-02 -7.2883.E-03 1.1135.E-03 -6.7702.E-05 S10 -2.0400.E+01 -1.4445.E-02 2.2319.E-03 -5.9120.E-05 -5.2918.E-06 S11 8.3447.E-01 -2.2231.E-02 -3.4868.E-04 1.0260.E-03 -1.7444.E-04 S12 2.6520.E+00 2.0724.E-02 -8.9739.E-03 1.8565.E-03 -1.4093.E-04 S13 2.7857.E+00 1.6853.E-02 -1.2500.E-03 -4.0621.E-05 4.9122.E-05 S14 1.8210.E+01 -2.6214.E-02 1.0575.E-03 -2.8050.E-04 3.7860.E-05 S15 -2.6076.E+01 -2.0768.E-02 1.7587.E-03 -1.6205.E-04 9.8983.E-06

[0116] Will refer to Figure 4 An imaging lens system according to a second example is described.

[0117] The imaging lens system 200 includes a first lens 210 , a second lens 220 , a third lens 230 , a fourth lens 240 , a fifth lens 250 , a sixth lens 260 , and a seventh lens 270 .

[0118] The first lens 210 has negative refractive power and has a convex object side surface and a concave image side surface. The second lens 220 has negative refractive power and has a concave object side surface and a convex image side surface. The third lens 230 has positive refractive power and has a convex object side surface and a convex image side surface. The fourth lens 240 has positive refractive power and has a convex object side surface and a convex image side surface. The fifth lens 250 has negative refractive power and has a concave object side surface and a concave image side surface. The sixth lens 260 has positive refractive power and has a convex object side surface and a convex image side surface. The seventh lens 270 has negative refractive power and has a convex object side surface and a concave image side surface.

[0119] The imaging lens system 200 may further include a stop ST, a filter IF, and an imaging surface IP. The stop ST may be disposed between the third lens 230 and the fourth lens 240. The imaging surface IP may be formed in the image sensor IS, and the filter IF may be disposed between the seventh lens 270 and the imaging surface IP. In addition, the cover glass may be formed integrally with the image sensor IS.

[0120] Figure 5 and Figure 6 The MTF characteristics of the imaging lens system 200 and the amount of change in the back focus (ΔBFL: μm) according to the temperature are shown.

[0121] Tables 3 and 4 show the lens characteristics and aspheric surface values ​​of the imaging lens system 200 .

[0122] Table 3

[0123]

[0124] Table 4

[0125] Face number K A B C D S8 6.1743.E-02 -2.4007.E-03 -2.9765.E-04 -2.4390.E-05 -1.9528.E-05 S9 -9.8752.E+00 1.1954.E-02 -7.3793.E-03 1.1236.E-03 -7.0377.E-05 S10 -3.3385.E+01 -1.2211.E-02 -2.6904.E-04 5.8774.E-04 -6.0860.E-05 S11 5.5242.E-01 -1.8889.E-02 -2.9707.E-03 1.5675.E-03 -1.9462.E-04 S12 2.3570.E+01 3.2261.E-02 -1.2069.E-02 2.2846.E-03 -1.6979.E-04 S13 2.7339.E+00 2.2043.E-02 -3.3001.E-03 5.6630.E-04 -2.6083.E-05 S14 1.3661.E+01 -9.6564.E-03 -2.4299.E-03 5.9171.E-04 -5.3941.E-05 S15 1.3526.E+01 -1.4778.E-02 1.2140.E-04 1.2956.E-04 -1.9478.E-05

[0126] Reference Figure 7 An imaging lens system according to a third example is described.

[0127] The imaging lens system 300 includes a first lens 310 , a second lens 320 , a third lens 330 , a fourth lens 340 , a fifth lens 350 , a sixth lens 360 , and a seventh lens 370 .

[0128] The first lens 310 has negative refractive power and has a convex object side surface and a concave image side surface. The second lens 320 has negative refractive power and has a concave object side surface and a convex image side surface. The third lens 330 has positive refractive power and has a convex object side surface and a convex image side surface. The fourth lens 340 has positive refractive power and has a convex object side surface and a convex image side surface. The fifth lens 350 has negative refractive power and has a concave object side surface and a concave image side surface. The sixth lens 360 has positive refractive power and has a convex object side surface and a convex image side surface. The seventh lens 370 has negative refractive power and has a convex object side surface and a concave image side surface.

[0129] The imaging lens system 300 may further include a stop ST, a filter IF, and an imaging surface IP. The stop ST may be disposed between the third lens 330 and the fourth lens 340. The imaging surface IP may be formed in the image sensor IS, and the filter IF may be disposed between the seventh lens 370 and the imaging surface IP. In addition, the cover glass may be formed integrally with the image sensor IS.

[0130] Figure 8 and Fig. 9 The MTF characteristics of the imaging lens system 300 and the amount of change in the back focus (ΔBFL: μm) according to the temperature are shown.

[0131] Tables 5 and 6 show lens characteristics and aspherical values ​​of the imaging lens system 300 .

[0132] Table 5

[0133]

[0134]

[0135] Table 6

[0136] Face number K A B C D S8 -4.7672.E+01 -1.8479.E-04 -1.2522.E-03 5.7369.E-05 -9.2322.E-06 S9 -1.1896.E+01 -6.2097.E-03 -1.7162.E-03 3.8513.E-04 -3.3577.E-05 S10 7.6939.E+01 -2.4136.E-02 7.2951.E-03 -9.5074.E-04 5.0715.E-05 S11 -4.2089.E-01 -2.8224.E-02 4.9170.E-03 -1.4101.E-04 -3.8423.E-05 S12 1.0819.E+01 1.4042.E-02 -7.2970.E-03 1.4972.E-03 -1.0629.E-04 S13 -8.4400.E+00 -5.7902.E-04 -1.0970.E-03 9.4651.E-05 1.8619.E-05 S14 5.5617.E+00 5.3117.E-04 -8.0796.E-03 1.6457.E-03 -1.1181.E-04 S15 2.1566.E+00 -1.6959.E-02 -2.7458.E-03 7.7632.E-04 -6.0830.E-05

[0137] Table 7 shows optical characteristic values ​​of the imaging lens systems according to the first example to the third example, and Table 8 shows conditional expression values ​​of the imaging lens systems according to the first example to the third example.

[0138] Table 7

[0139] refer to First example Second example Third Example TTL 19.000 18.989 19.001 BFL 3.100 3.100 3.100 f 3.325 3.320 3.278 f1 -6.240 -6.318 -5.691 f2 -18.412 -16.640 -37.013 f3 5.947 5.973 5.997 f4 5.115 4.616 7.104 f5 -3.345 -3.304 -4.180 f6 5.873 7.147 4.764 f7 -39.005 -203.622 -14.831

[0140] Table 8

[0141] Conditional Expressions First example Second example Third Example V1 / Nd1 27.9865 27.9865 27.9865 V2 / Nd2 42.3006 42.3006 42.3006 V3 / Nd3 25.7761 25.7761 25.7761 V4 / Nd4 36.3879 36.3879 36.3879 V5 / Nd5 14.3502 14.3502 14.3502 V6 / Nd6 36.3879 36.3879 36.3879 V7 / Nd7 36.3879 36.3879 14.0261 Vmin13 / Ndmin13 30.6526 30.6526 30.6526 Vmax47 / Ndmax47 34.0977 34.0977 34.0956 f / f3 0.5591 0.5559 0.5466 f34*0.8 2.3249 2.2075 2.7262 Nd3 / Nd4 1.1741 1.1741 1.1741

[0142] As described above, according to various examples, an imaging lens system capable of achieving constant optical characteristics even in a high temperature or low temperature environment can be provided.

[0143] Although the present disclosure includes specific examples, it will be apparent to those skilled in the art that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be understood in a descriptive sense only and not for limiting purposes. The description of the features or aspects in each example should be considered to be applicable to similar features or aspects in other examples. If the described techniques are performed to have components in a different order, and / or if they are combined in different ways and / or replaced or supplemented by other components or their equivalents in the described system, architecture, device or circuit, appropriate results can still be achieved. Therefore, the scope of the present disclosure is not limited by specific embodiments, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included in the present disclosure.

Claims

1. Imaging lens system, including: A first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens are arranged in order from the object side. wherein the first lens has negative refractive power, a convex object side surface and a concave image side surface, the second lens has negative refractive power, a concave object side surface and a convex image side surface, the third lens has positive refractive power, a convex object side surface and a convex image side surface, the fourth lens has positive refractive power, a convex object side surface and a convex image side surface, the fifth lens has negative refractive power, a concave object side surface and a concave image side surface, the sixth lens has positive refractive power, a convex object side surface and a convex image side surface, and the seventh lens has negative refractive power, a convex object side surface and a concave image side surface, wherein at least one of the first to seventh lenses has at least one aspherical surface, The third lens has a 2.2×10 -6 / ℃ to 3.5×10 -6 / ℃ refractive index temperature coefficient, in, <h2 style=";text-align:left;direction:ltr">0 < f34<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> 0.8 < f, Wherein, f is the focal length of the imaging lens system, and f34 is the combined focal length of the third lens and the fourth lens, and The imaging lens system has seven lenses in total.

2. The imaging lens system according to claim 1, wherein: The first lens, the second lens, and the third lens are formed of a material different from that of the fourth lens, the fifth lens, the sixth lens, and the seventh lens.

3. The imaging lens system according to claim 1, wherein: 35 < V2 / Nd2 < 45, Wherein, V2 is the Abbe number of the second lens, and Nd2 is the refractive index of the second lens.

4. The imaging lens system according to claim 1, wherein: 20 < V3 / Nd3 < 30, Wherein, V3 is the Abbe number of the third lens, and Nd3 is the refractive index of the third lens.

5. The imaging lens system according to claim 1, wherein: 10 < V5 / Nd5 < 20, Wherein, V5 is the Abbe number of the fifth lens, and Nd5 is the refractive index of the fifth lens.

6. The imaging lens system according to claim 1, wherein: 30 < V6 / Nd6 < 40, Wherein, V6 is the Abbe number of the sixth lens, and Nd6 is the refractive index of the sixth lens.

7. The imaging lens system according to claim 1, wherein: 27 < Vmin13 / Ndmin13 < 37, Among them, Vmin13 is the minimum value among the Abbe number of the first lens, the Abbe number of the second lens and the Abbe number of the third lens, and Ndmin13 is the minimum value among the refractive index of the first lens, the refractive index of the second lens and the refractive index of the third lens.

8. The imaging lens system according to claim 1, wherein: 30 < Vmax47 / Ndmax47 < 35, Among them, Vmax47 is the maximum value among the Abbe number of the fourth lens, the Abbe number of the fifth lens, the Abbe number of the sixth lens and the Abbe number of the seventh lens, and Ndmax47 is the maximum value among the refractive index of the fourth lens, the refractive index of the fifth lens, the refractive index of the sixth lens and the refractive index of the seventh lens.

9. The imaging lens system according to claim 1, wherein: 0.4 < f / f3 < 0.9, Wherein, f3 is the focal length of the third lens.

10. Imaging lens system, comprising: A first lens element having negative refractive power and a convex object-side surface and a concave image-side surface; A second lens element having negative refractive power, a concave object-side surface and a convex image-side surface; A third lens element having positive refractive power and a convex object-side surface and a convex image-side surface; a fourth lens element having positive refractive power and a convex object-side surface and a convex image-side surface; a fifth lens element having negative refractive power and a concave object-side surface and a concave image-side surface; a sixth lens element having positive refractive power and a convex object-side surface and a convex image-side surface; as well as The seventh lens has negative refractive power and a convex object-side surface and a concave image-side surface. Wherein, the first lens to the seventh lens are arranged in sequence from the object side, wherein at least one of the first lens to the seventh lens has at least one aspherical surface, The first lens has a 2.5×10 -6 / ℃ to 4.5×10 -6 / ℃ refractive index temperature coefficient, in, <h2 style=";text-align:left;direction:ltr">0 < f34<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr"> 0.8 < f, Wherein, f is the focal length of the imaging lens system, and f34 is the combined focal length of the third lens and the fourth lens, and The imaging lens system has seven lenses in total.

11. The imaging lens system according to claim 10, wherein: The second lens has a 1.0×10 -6 / ℃ to 2.5×10 -6 / ℃ refractive index temperature coefficient.

12. The imaging lens system according to claim 10, wherein: The fourth lens has a -110×10 -6 / ℃ to -80×10 -6 / ℃ refractive index temperature coefficient.

13. The imaging lens system according to claim 10, wherein: 1.1 < Nd3 / Nd4 < 1.2, Wherein, Nd3 is the refractive index of the third lens, and Nd4 is the refractive index of the fourth lens.

Images