Imaging lens system

Abstract

The imaging lens system comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged from the object side of the imaging lens system to the imaging surface of the imaging lens system along the optical axis of the imaging lens system, the third lens has a convex image side surface in a paraxial region thereof, and the imaging lens system satisfies the conditional expression 0.3 lt; f / f4lt; f is the focal length of the imaging lens system, and f4 is the focal length of the fourth lens.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of priority of Korean Patent Application No. 10 - 2024 - 0121066, filed on September 5, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. Technical field

[0003] The present disclosure relates to an imaging lens system that can achieve certain optical performance regardless of changes in the temperature of the surrounding environment. Background art

[0004] A small surveillance camera can be configured to capture image information within a surveillance area. For example, a small surveillance camera can be mounted on the front bumper, rear bumper, or a part of a vehicle, and can provide the captured image to a driver.

[0005] Early small surveillance cameras were designed to capture images of obstacles in neighboring vehicles, and thus not only had a relatively low resolution, but the resolution varied greatly according to temperature changes between - 40°C and 80°C. However, as the requirements for the autonomous driving function of vehicles increase, it may be necessary to develop a surveillance camera with high resolution and certain optical characteristics even under harsh temperature conditions. Summary of the invention

[0006] Providing this summary section is intended to introduce, in a brief form, a selection of concepts that will be further described in the detailed description section below. This summary section is not intended to identify the 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.

[0007] 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, a seventh lens, and an eighth lens that are sequentially arranged along the optical axis of the imaging lens system from the object side of the imaging lens system toward the imaging surface of the imaging lens system, wherein the second lens has a positive refractive power, the third lens has a convex image side surface in its paraxial region, and the imaging lens system satisfies the conditional expression 0.3 < f / f4 < 0.4, where f is the focal length of the imaging lens system, and f4 is the focal length of the fourth lens.

[0008] The first lens may have a convex object side surface in its paraxial region.

[0009] The second lens may have a concave object side surface in its paraxial region.

[0010] The fourth lens may have a convex object side surface in its paraxial region.

[0011] The fifth lens can have a convex object side surface in its paraxial region.

[0012] The sixth lens can have a convex object side surface in its paraxial region.

[0013] The sixth lens can have a concave object side surface in its paraxial region.

[0014] The seventh lens can have a convex object side surface in its paraxial region.

[0015] The eighth lens can have a convex object side surface in its paraxial region.

[0016] In another general aspect, an imaging lens system includes, in order from an object side of the imaging lens system toward an image plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, wherein the second lens has positive refractive power, and the imaging lens system satisfies a conditional expression 2.0 < TTL / f4 < 3.0, where TTL is a distance from an object side surface of the first lens to the image plane along the optical axis, and f4 is a focal length of the fourth lens.

[0017] The object side surface of the first lens can be convex in its paraxial region.

[0018] The object side surface of the second lens can be concave in its paraxial region.

[0019] The object side surface of the fourth lens can be convex in its paraxial region

[0020] The object side surface of the fifth lens can be convex in its paraxial region.

[0021] The object side surface of the sixth lens can be convex in its paraxial region.

[0022] The object side surface of the sixth lens can be concave in its paraxial region.

[0023] The object side surface of the seventh lens can be convex in its paraxial region.

[0024] The object side surface of the eighth lens can be convex in its paraxial region.

[0025] In another general aspect, an imaging lens system includes, in order from an object side of the imaging lens system toward an image plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, wherein the imaging lens system satisfies a conditional expression -1.6 < R3 / f4 < -0.4, where R3 is a curvature radius of an object side surface of the second lens at the optical axis, and f4 is a focal length of the fourth lens.

[0026] The second lens can have a positive refractive power.

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

[0028] Figure 1 is a configuration diagram of an imaging lens system according to a first embodiment of the present disclosure.

[0029] Figure 2 shows Figure 1 aberration curves of the imaging lens system shown in

[0030] Figure 3 is a configuration diagram of an imaging lens system according to a second embodiment of the present disclosure.

[0031] Figure 4 shows Figure 3 aberration curves of the imaging lens system shown in

[0032] Figure 5 is a configuration diagram of an imaging lens system according to a third embodiment of the present disclosure.

[0033] Figure 6 shows Figure 5 aberration curves of the imaging lens system shown in

[0034] Figure 7 is a configuration diagram of an imaging lens system according to a fourth embodiment of the present disclosure.

[0035] Figure 8 shows Figure 7 aberration curves of the imaging lens system shown in

[0036] Figure 9 is a configuration diagram of an imaging lens system according to a fifth embodiment of the present disclosure.

[0037] Figure 10 shows Figure 9 aberration curves of the imaging lens system shown in

[0038] Figure 11is a configuration diagram of an imaging lens system according to a sixth embodiment of the present disclosure.

[0039] Figure 12 shows Figure 11 aberration curves of the imaging lens system shown in

[0040] Figure 13 is a configuration diagram of an imaging lens system according to a seventh embodiment of the present disclosure.

[0041] Figure 14 shows Figure 13 aberration curves of the imaging lens system shown in

[0042] Throughout the drawings and specific embodiments, identical reference numerals designate identical elements, or elements with equivalent functions. The drawings can not be to scale and the relative dimensions, proportions and depiction of elements in the drawings can be exaggerated for purpose of clarity, illustration and convenience. DETAILED DESCRIPTION

[0043] The following detailed description is presented to aid in understanding the method, apparatus and / or system described herein. Various changes, modifications and equivalents can be used and will be apparent to those skilled in the art once the disclosure is understood. For example, the order of the operations described herein can be altered, except that certain operations must be performed before or after others, as will be apparent to those skilled in the art upon reading the description herein. Additionally, certain features can be omitted or consolidated, and other features can be added to provide a complete understanding of the method, apparatus and / or system described herein. The following detailed description is presented to enable any person skilled in the art to make and use the method, apparatus and / or system described herein.

[0044] The features described herein can be implemented in different forms and should not be construed as limited to the examples described herein. Rather, these examples are provided as illustration of some of the many possible implementations of the method, apparatus and / or system described herein.

[0045] Throughout the specification, when an element such as a layer, region or substrate is referred to as being "on" or "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.

[0046] As used herein, 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.

[0047] Although terms such as “first,” “second,” and “third” can be used herein to describe various elements, components, regions, layers, or sections, these elements, components, regions, layers, or sections should not be limited by these terms. Rather, these terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, elements, components, regions, layers, or sections referred to as first, second, third, etc., in the examples described herein can also be referred to as second, third, etc., in other examples without departing from the teachings of the examples described herein.

[0048] Spatially relative terms such as “on,” “above,” “under,” and “below” can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Such spatially relative terms are not intended to limit the position of a device to the position as shown in the figures. With respect to the devices illustrated in the figures, the spatially relative terms are intended to encompass various

[0049] The terminology used herein is for the purpose of describing various examples only and is not intended to be limiting of the present disclosure. Unless otherwise defined, the terms “a,” “one,” and “the” are intended to include both singular and plural forms. The terms “including,” “comprising,” and “having” are meant to be inclusive and to mean that there can be additional elements, quantities, operations, components, members, and / or combinations thereof, but not excluding the possibility of one or more other features, quantities, operations, components, members, and / or combinations thereof.

[0050] In the present specification, the first lens refers to the lens closest to an object (or a subject), and the eighth lens refers to the lens closest to an imaging plane (or an image sensor). In the present specification, the radius of curvature, the thickness of a lens or other component, the distance between lenses or other components, the TTL (distance from the object side surface of the first lens to the imaging plane along the optical axis), the IMGHT (height of the imaging plane), and the focal length are expressed in millimeters (mm). Furthermore, the rate of change of the refractive index (DTn) and the coefficient of thermal expansion (CTE) according to a change in temperature described in the present specification are expressed in ppm / °C, where ppm represents parts per million.

[0051] The thickness of a lens or other component, the distance between lenses or other components, and the TTL are measured along the optical axis.

[0052] Furthermore, in the description of the lens shape, the expression that the surface of a lens is convex means that the paraxial region of the surface is convex, and the expression that the surface of a lens is concave means that the paraxial region of the surface is concave.

[0053] Therefore, even when the expression that the surface of a lens is convex, the edge portion of the surface can be concave. Similarly, even when the expression that the surface of a lens is concave, the edge portion of the surface can be convex.

[0054] The paraxial region of a lens surface is a very narrow region of the lens surface close to the optical axis of the lens surface.

[0055] More specifically, the paraxial region of a lens surface is a central portion of the lens surface around and including the optical axis of the lens surface, in which the light rays incident to the lens surface form a small angle θ with the optical axis, and the approximations sin θ ≈ θ, tan θ ≈ θ, and cos θ ≈ 1 are valid.

[0056] An imaging lens system according to a first aspect of the disclosure can include a plurality of lenses. For example, the imaging lens system according to the first aspect can include, in order from an object side of the imaging lens system toward an imaging plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The imaging lens system according to the first aspect can include a lens having a positive refractive power. For example, in the imaging lens system according to the first aspect, the second lens can have a positive refractive power. The imaging lens system according to the first aspect can include a lens having a convex image side surface. For example, in the imaging lens system according to the first aspect, the third lens can have a convex image side surface. The imaging lens system according to the first aspect can satisfy a certain conditional expression. For example, the imaging lens system according to the first aspect can satisfy a conditional expression 0.3 < f / f4 < 0.4, where f is a focal length of the imaging lens system, and f4 is a focal length of the fourth lens.

[0057] An imaging lens system according to a second aspect of the disclosure can include a plurality of lenses. For example, the imaging lens system according to the second aspect can include, in order from an object side of the imaging lens system toward an imaging plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The imaging lens system according to the second aspect can include a lens having a positive refractive power. For example, in the imaging lens system according to the second aspect, the second lens can have a positive refractive power. The imaging lens system according to the second aspect can satisfy a certain conditional expression. For example, the imaging lens system according to the second aspect can satisfy a conditional expression 2.0 < TTL / f4 < 3.0, where TTL is a distance from an object side surface of the first lens to the imaging plane along the optical axis, and f4 is a focal length of the fourth lens.

[0058] An imaging lens system according to a third aspect of the disclosure can include a plurality of lenses. For example, the imaging lens system according to the third aspect can include, in order from an object side of the imaging lens system toward an imaging plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The imaging lens system according to the third aspect can include a stop. For example, the imaging lens system according to the third aspect can include a stop disposed between the fourth lens and the fifth lens. The imaging lens system according to the third aspect can include lenses made of a glass material. For example, in the imaging lens system according to the third aspect, the first lens, the second lens, the fourth lens, the sixth lens, and the seventh lens can be made of a glass material. The imaging lens system according to the third aspect can include cemented lenses.

[0059] For example, in the imaging lens system according to the third aspect, the sixth lens and the seventh lens can be cemented to each other. In detail, in the imaging lens system according to the third aspect, a distance between the sixth lens and the seventh lens (a distance along the optical axis from an image-side surface of the sixth lens to an object-side surface of the seventh lens) can be less than about 0.01 mm, and can be filled with an adhesive, and a curvature radius of the image-side surface of the sixth lens and a curvature radius of the object-side surface of the seventh lens can be substantially equal to each other.

[0060] The imaging lens system according to the fourth aspect of the present disclosure can include a plurality of lenses. For example, the imaging lens system according to the fourth aspect can include, in order from an object side of the imaging lens system toward an imaging plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The imaging lens system according to the fourth aspect can include a stop. For example, the imaging lens system according to the fourth aspect can include a stop disposed between the fourth lens and the fifth lens. The imaging lens system according to the fourth aspect can include a lens having a certain optical property. For example, in the imaging lens system according to the fourth aspect, the fourth lens can satisfy either or both of the condition expressions 1.0 < L4DnT < 4.0 and 5.0 < L4CTE < 9.0 (based on a wavelength of 587.6 nm). In these condition expressions, L4DnT is a refractive index change rate of the fourth lens according to a temperature change, expressed in ppm / °C, and L4CTE is a coefficient of thermal expansion of the fourth lens, expressed in ppm / °C.

[0061] The imaging lens system according to the fifth aspect of the present disclosure can include, in order from an object side of the imaging lens system toward an imaging plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, and can satisfy any one or any combination of any two or more of the following condition expressions:

[0062] 0.3 < f / f4 < 0.4 (condition expression 1)

[0063] -1.0 < L4DnT < 4.0 (ppm / °C) (condition expression 2)

[0064] 5.0 < L4CTE < 9.0 (ppm / °C) (condition expression 3)

[0065] 1.65 < Nd4 < 1.90 (condition expression 4)

[0066] In the above conditional expression, f is a focal length of the imaging lens system, f4 is a focal length of the fourth lens, L4DnT is a rate of change of a refractive index of the fourth lens according to a temperature change, L4CTE is a coefficient of thermal expansion of the fourth lens, and Nd4 is a refractive index of the fourth lens.

[0067] The imaging lens system according to the sixth aspect of the present disclosure can include, in order from an object side of the imaging lens system toward an imaging plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, and can satisfy any one or any combination of any two or more of the following conditional expressions:

[0068] -1.0 < f1 / f4 < -0.20 (Conditional Expression 5)

[0069] 1.2 < f2 / f4 < 3.20 (Conditional Expression 6)

[0070] -8.0 < f3 / f4 < -1.0 (Conditional Expression 7)

[0071] 0.80 < f5 / f4 < 1.80 (Conditional Expression 8)

[0072] -1.0 < f6 / f4 < -0.20 (Conditional Expression 9)

[0073] 0.20 < f7 / f4 < 1.20 (Conditional Expression 10)

[0074] 1.0 < f8 / f4 < 90 (Conditional Expression 11)

[0075] 2.0 < TTL / f4 < 3.0 (Conditional Expression 12)

[0076] 1.2 < R1 / f4 < 2.40 (Conditional Expression 13)

[0077] -1.6 < R3 / f4 < -0.4 (Conditional Expression 14)

[0078] In the above conditional expression, 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, f5 is a focal length of the fifth lens, f6 is a focal length of the sixth lens, f7 is a focal length of the seventh lens, f8 is a focal length of the eighth lens, TTL is a distance along the optical axis from an object side surface of the first lens to the imaging plane, R1 is a radius of curvature of the object side surface of the first lens at the optical axis, and R3 is a radius of curvature of the object side surface of the second lens at the optical axis.

[0079] An imaging lens system according to a seventh aspect of the present disclosure can include, in order from an object side of the imaging lens system toward an imaging plane of the imaging lens system along an optical axis of the imaging lens system, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, and can satisfy any one or any combination of any two or more of the following conditional expressions:

[0080] -2.0 < f6 / f < -1.2 (Conditional Expression 15)

[0081] 1.0 < f7 / f < 2.6 (Conditional Expression 16)

[0082] -1.2 < f6 / f7 < -0.6 (Conditional Expression 17)

[0083] -1.6 < (R1+R3) / R4 < -0.6 (Conditional Expression 18)

[0084] 0.8 < (R5+R6) / R3 < 1.4 (Conditional Expression 19)

[0085] -1.4 < (R4+R5) / R7 < -0.8 (Conditional Expression 20)

[0086] In the above conditional expressions, R4 is a radius of curvature of an image-side surface of the second lens at the optical axis, R5 is a radius of curvature of an object-side surface of the third lens at the optical axis, R6 is a radius of curvature of an image-side surface of the third lens at the optical axis, and R7 is a radius of curvature of an object-side surface of the fourth lens at the optical axis.

[0087] An imaging lens system according to an eighth aspect of the present disclosure can include any combination of any two or more of the first through seventh aspects having the following properties. For example, an imaging lens system according to the eighth aspect can include the properties of the first aspect and can satisfy any one or any combination of any two or more of the conditional expressions according to the fifth aspect. As another example, an imaging lens system according to the eighth aspect can include the properties of the second aspect and can satisfy any one or any combination of any two or more of the conditional expressions according to the sixth or seventh aspect.

[0088] The imaging lens system according to the first aspect to the eighth aspect can include any one or any combination of any two or more of the first lens to the eighth lens having the characteristics described below. As an example, the imaging lens system according to the first aspect can include one of the first lens to the eighth lens having the characteristics described below. As another example, the imaging lens system according to the second aspect can include any combination of any two or more of the first lens to the eighth lens having the characteristics described below. However, the imaging lens system according to the above-described aspects does not necessarily include a lens having the characteristics described below. The characteristics of the first lens to the eighth lens are described below.

[0089] The first lens can have a refractive power. For example, the first lens can have a negative refractive power. The first lens can have a convex shape on one surface. For example, the first lens can have a convex object side surface. The first lens can include a spherical surface or an aspherical surface. For example, both surfaces of the first lens can be spherical. The first lens can be made of a material having high light transmittance and excellent processing performance. For example, the first lens can be made of a glass material. The first lens can have characteristics advantageous for improving aberration. For example, the first lens can have a refractive index of 1.78 or more and an Abbe number of 40 or more.

[0090] The second lens can have a refractive power. For example, the second lens can have a positive refractive power. The second lens can have a concave shape on one surface. For example, the second lens can have a concave object side surface. The second lens can include a spherical surface. For example, both surfaces of the second lens can be spherical. The second lens can be made of a material having high light transmittance and excellent processing performance. For example, the second lens can be made of a glass material. The second lens can have a predetermined refractive index. For example, the refractive index of the second lens can be 1.80 or more. The second lens can have a predetermined Abbe number. For example, the Abbe number of the second lens can be greater than 30 and less than 50.

[0091] The third lens can have a refractive power. For example, the third lens can have a negative refractive power. The third lens can have a convex shape on one surface. For example, the third lens can have a convex image side surface. The third lens can include an aspherical surface. For example, both surfaces of the third lens can be aspherical. The third lens can be made of a material different from that of the second lens. For example, the third lens can be made of a plastic material. The third lens can have a predetermined refractive index. For example, the third lens can have a refractive index of 1.50 or more. The third lens can have a predetermined Abbe number. For example, the Abbe number of the third lens can be greater than 52.

[0092] The fourth lens may have refractive power. For example, the fourth lens may have positive refractive power. The fourth lens may have a convex shape on one surface. For example, the fourth lens may have a convex object-side surface. The fourth lens may include a spherical surface. For example, both surfaces of the fourth lens may be spherical. The fourth lens may be made of a material different from that of the third lens. For example, the fourth lens may be made of glass. The fourth lens may have a predetermined refractive index. For example, the refractive index of the fourth lens may be 1.7 or greater. The fourth lens may have a predetermined Abbe number. For example, the Abbe number of the fourth lens may be greater than 46.

[0093] The fifth lens may have refractive power. For example, the fifth lens may have positive refractive power. The fifth lens may have a convex shape on one surface. For example, the fifth lens may have a convex object-side surface. The fifth lens may include an aspherical surface. For example, both surfaces of the fifth lens may be aspherical. The fifth lens may be made of a material different from that of the fourth lens. For example, the fifth lens may be made of a plastic material. The fifth lens may have a predetermined refractive index. For example, the refractive index of the fifth lens may be less than 1.6. The fifth lens may have a predetermined Abbe number. For example, the Abbe number of the fifth lens may be greater than 52.

[0094] The sixth lens may have refractive power. For example, the sixth lens may have negative refractive power. The sixth lens may have a convex shape on one surface. For example, the sixth lens may have a convex object-side surface. Alternatively, the sixth lens may have a concave object-side surface and a concave image-side surface. The sixth lens may include a spherical or aspherical surface. For example, both surfaces of the sixth lens may be spherical, or one surface may be aspherical. The sixth lens may be made of a material different from that of the fifth lens. For example, the sixth lens may be made of glass. The sixth lens may have a predetermined refractive index. For example, the refractive index of the sixth lens may be greater than 1.6. The sixth lens may have a predetermined Abbe number. For example, the Abbe number of the sixth lens may be less than 30.

[0095] The seventh lens may have refractive power. For example, the seventh lens may have positive refractive power. The seventh lens may have a convex shape on one surface. For example, the seventh lens may have a convex object-side surface. The seventh lens may include a spherical or aspherical surface. For example, both surfaces of the seventh lens may be spherical, or the image-side surface may be aspherical. The seventh lens may be made of the same material as the sixth lens. For example, the seventh lens may be made of glass. The seventh lens may have a predetermined refractive index. For example, the refractive index of the seventh lens may be 1.5 or greater. The seventh lens may have a predetermined Abbe number. For example, the Abbe number of the seventh lens may be greater than 60. Alternatively, the Abbe number of the seventh lens may be greater than 52. The seventh lens may be cemented to the sixth lens. For example, the radius of curvature of the object-side surface of the seventh lens may be substantially equal to the radius of curvature of the image-side surface of the sixth lens.

[0096] The eighth lens may have refractive power. For example, the eighth lens may have positive refractive power. The eighth lens may have a convex shape on one surface. For example, the eighth lens may have a convex object-side surface. The eighth lens may include an aspherical surface. For example, both surfaces of the eighth lens may be aspherical. Alternatively, both surfaces of the eighth lens may be spherical. The eighth lens may be made of a material different from that of the seventh lens. For example, the eighth lens may be made of a plastic material. The eighth lens may have a predetermined refractive index. For example, the refractive index of the eighth lens may be 1.50 or greater. The eighth lens may have a predetermined Abbe number. For example, the Abbe number of the eighth lens may be 52 or greater.

[0097] The aspherical surface of a lens is defined by the following Equation 1:

[0098]

[0099] In Equation 1, c is the curvature of the lens surface, and is equal to the reciprocal of the radius of curvature of the lens surface at the optical axis. k is the quadratic constant, and r is the distance from any point on the aspherical surface of the lens to the optical axis. Furthermore, constants A to H are aspherical surface coefficients. Z (also called sag) is the distance in a direction parallel to the optical axis between a point on the aspherical surface of the lens at a distance r from the optical axis and a tangent plane perpendicular to the optical axis and intersecting the vertex of the aspherical surface.

[0100] An imaging lens system may include lenses made of different materials. For example, the first, second, fourth, sixth, and seventh lenses may be made of materials different from those of the third, fifth, and eighth lenses. As a specific example, the first, second, fourth, sixth, and seventh lenses may be made of glass, which has a low coefficient of thermal expansion due to external impact and temperature changes, and the third, fifth, and eighth lenses may be made of a plastic material that is easy to process. However, the materials of the first through eighth lenses are not limited to the examples described above. For example, the second lens may be changed to be made of a plastic material, and the third lens may be changed to be made of glass.

[0101] An imaging lens system may include an aperture stop, an imaging plane, and a filter.

[0102] An aperture stop can be positioned between two lenses in a lens system. For example, an aperture stop can be positioned between a fourth lens and a fifth lens. As another example, an aperture stop can be positioned on the object side of a lens made of glass material and having positive refractive power. An imaging plane can be formed at the point where the light refracted by the first to eighth lenses forms an image. The imaging plane can be formed by an image sensor. For example, the imaging plane can be formed on the surface of the image sensor or on the inner layer of the image sensor. A filter can be positioned between the eighth lens and the imaging plane. The filter can block light of a specific wavelength. For example, the filter can block infrared wavelengths of light.

[0103] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0104] Figure 1 This is a configuration diagram of an imaging lens system according to a first embodiment of the present disclosure. Figure 2 It shows Figure 1 The aberration curves of the imaging lens system are shown.

[0105] Reference Figure 1 The imaging lens system 100 may include a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a seventh lens 170, and an eighth lens 180.

[0106] The first lens 110 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 120 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The third lens 130 can have negative refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 140 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The fifth lens 150 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 160 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The seventh lens 170 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The eighth lens 180 can have positive refractive power and can have a convex object-side surface and a concave image-side surface.

[0107] The imaging lens system 100 may further include an aperture stop ST, a filter IF, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 140 and the fifth lens 150. The imaging surface IP may be formed on the image sensor IS, and the filter IF may be positioned between the eighth lens 180 and the imaging surface IP.

[0108] Tables 1 and 2 below show the lens characteristics and aspherical values ​​of the imaging lens system 100.

[0109] Table 1

[0110]

[0111] Table 2

[0112]

[0113]

[0114] Figure 3 This is a configuration diagram of an imaging lens system according to a second embodiment of the present disclosure. Figure 4 It shows Figure 3 The aberration curves of the imaging lens system are shown.

[0115] Reference Figure 3 The imaging lens system 200 may include a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, a seventh lens 270, and an eighth lens 280.

[0116] The first lens 210 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 220 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The third lens 230 can have negative refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 240 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The fifth lens 250 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 260 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The seventh lens 270 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The eighth lens 280 can have positive refractive power and can have a convex object-side surface and a concave image-side surface.

[0117] The imaging lens system 200 may further include an aperture stop ST, a filter IF, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 240 and the fifth lens 250. The imaging surface IP may be formed on the image sensor IS, and the filter IF may be positioned between the eighth lens 280 and the imaging surface IP.

[0118] Tables 3 and 4 below show the lens characteristics and aspherical values ​​of the imaging lens system 200.

[0119] Table 3

[0120]

[0121] Table 4

[0122] Surface number S5 S6 S10 S11 S15 S16 k -2.393E+00 -1.600E+01 -1.904E+00 -2.696E+01 9.900E+01 -9.900E+01 A 8.639E-03 1.979E-01 -8.370E-02 -1.549E-01 -4.871E-01 -5.833E-01 B -2.897E-03 8.310E-04 -1.447E-02 -1.635E-02 -1.907E-02 1.170E-02 C -5.604E-05 -2.335E-03 -1.780E-03 -1.840E-03 6.698E-04 6.475E-03 D 2.547E-04 6.823E-04 -2.680E-04 -2.326E-04 5.957E-04 8.096E-04 E -3.889E-05 -1.405E-04 -1.609E-05 0 1.062E-04 2.876E-04 F 0 3.020E-05 1.099E-05 0 0 0 G 0 -6.399E-07 1.081E-05 0 0 0

[0123] Figure 5 This is a configuration diagram of an imaging lens system according to a third embodiment of the present disclosure. Figure 6 It shows Figure 5 The aberration curves of the imaging lens system are shown.

[0124] Reference Figure 5 The imaging lens system 300 may include a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, a seventh lens 370, and an eighth lens 380.

[0125] The first lens 310 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 320 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The third lens 330 can have negative refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 340 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The fifth lens 350 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 360 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The seventh lens 370 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The eighth lens 380 can have positive refractive power and can have a convex object-side surface and a convex image-side surface.

[0126] The imaging lens system 300 may further include an aperture stop ST, a filter IF, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 340 and the fifth lens 350. The imaging surface IP may be formed on the image sensor IS, and the filter IF may be positioned between the eighth lens 380 and the imaging surface IP.

[0127] Tables 5 and 6 below show the lens characteristics and aspherical values ​​of the imaging lens system 300.

[0128] Table 5

[0129]

[0130]

[0131] Table 6

[0132] Surface number S5 S6 S10 S11 S15 S16 k -2.212E+00 -1.995E+01 -2.176E+00 9.858E+01 9.900E+01 3.451E+00 A 3.008E-02 2.020E-01 -5.356E-02 -6.523E-02 -5.229E-01 -6.110E-01 B -4.039E-03 -5.851E-04 -1.887E-02 -1.443E-02 -3.051E-02 1.787E-03 C 1.811E-04 -1.630E-03 -3.077E-03 -1.839E-03 -1.558E-03 6.103E-03 D 1.861E-04 3.827E-04 -5.813E-04 -1.932E-04 1.685E-04 7.532E-04 E -1.328E-05 -6.055E-05 -1.202E-04 0 5.991E-05 2.880E-04 F 0 8.122E-06 -2.140E-05 0 0 0 G 0 4.255E-06 0 0 0 0

[0133] Figure 7 This is a configuration diagram of an imaging lens system according to the fourth embodiment of this disclosure. Figure 8 It shows Figure 7 The aberration curves of the imaging lens system are shown.

[0134] Reference Figure 7 The imaging lens system 400 may include a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, a seventh lens 470, and an eighth lens 480.

[0135] The first lens 410 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 420 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The third lens 430 can have negative refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 440 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The fifth lens 450 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 460 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The seventh lens 470 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The eighth lens 480 can have positive refractive power and can have a convex object-side surface and a concave image-side surface.

[0136] The imaging lens system 400 may further include an aperture stop ST, a filter IF, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 440 and the fifth lens 450. The imaging surface IP may be formed on the image sensor IS, and the filter IF may be positioned between the eighth lens 480 and the imaging surface IP.

[0137] Tables 7 and 8 below show the lens characteristics and aspherical values ​​of the imaging lens system 400.

[0138] Table 7

[0139]

[0140] Table 8

[0141]

[0142]

[0143] Figure 9 This is a configuration diagram of an imaging lens system according to the fifth embodiment of this disclosure. Figure 10 It shows Figure 9 The aberration curves of the imaging lens system are shown.

[0144] Reference Figure 9 The imaging lens system 500 may 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.

[0145] The first lens 510 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 520 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The third lens 530 can have negative refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 540 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The fifth lens 550 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 560 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 570 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The eighth lens 580 can have positive refractive power and can have a concave object-side surface and a convex image-side surface.

[0146] The imaging lens system 500 may further include an aperture stop ST, a filter IF, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 540 and the fifth lens 550. The imaging surface IP may be formed on the image sensor IS, and the filter IF may be positioned between the eighth lens 580 and the imaging surface IP.

[0147] Tables 9 and 10 below show the lens characteristics and aspherical values ​​of the imaging lens system 500.

[0148] Table 9

[0149]

[0150]

[0151] Table 10

[0152] Surface number S5 S6 S10 S11 S15 S16 k -2.239E+00 -3.940E+00 1.461E+01 -4.151E-02 -8.042E+00 9.900E+01 A -2.757E-01 -1.297E-01 -1.089E-01 -1.167E-01 -6.332E-01 -8.184E-01 B 3.302E-02 2.586E-02 -1.679E-02 -2.118E-02 -6.182E-02 -3.722E-02 C -2.058E-03 -2.371E-03 -1.955E-03 -1.808E-03 -7.685E-03 7.518E-04 D 2.627E-04 3.720E-04 -4.136E-04 -2.542E-04 -1.188E-03 -2.752E-04 E 1.997E-05 -1.002E-04 -8.182E-06 0 -1.068E-04 1.746E-04 F 0 3.559E-05 -2.432E-06 0 0 0 G 0 -1.244E-05 2.161E-05 0 0 0

[0153] Figure 11 This is a configuration diagram of an imaging lens system according to the sixth embodiment of this disclosure. Figure 12 It shows Figure 11 The aberration curves of the imaging lens system are shown.

[0154] Reference Figure 11 The imaging lens system 600 may include a first lens 610, a second lens 620, a third lens 630, a fourth lens 640, a fifth lens 650, a sixth lens 660, a seventh lens 670, and an eighth lens 680.

[0155] The first lens 610 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 620 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The third lens 630 can have negative refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 640 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The fifth lens 650 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 660 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 670 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The eighth lens 680 can have positive refractive power and can have a concave object-side surface and a convex image-side surface.

[0156] The imaging lens system 600 may further include an aperture stop ST, a filter IF, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 640 and the fifth lens 650. The imaging surface IP may be formed on the image sensor IS, and the filter IF may be positioned between the eighth lens 680 and the imaging surface IP.

[0157] Tables 11 and 12 below show the lens characteristics and aspherical values ​​of the imaging lens system 600.

[0158] Table 11

[0159]

[0160]

[0161] Table 12

[0162] Surface number S5 S6 S10 S11 S15 S16 k -2.217E+00 -3.771E+00 2.524E+01 -4.791E-01 -6.007E+01 8.667E+01 A -2.967E-01 -1.480E-01 -1.033E-01 -1.047E-01 -6.106E-01 -8.814E-01 B 3.800E-02 2.887E-02 -1.562E-02 -1.906E-02 -6.114E-02 -4.293E-02 C -2.369E-03 -2.528E-03 -1.741E-03 -1.582E-03 -7.291E-03 5.949E-04 D 3.539E-04 2.884E-04 -3.560E-04 -2.379E-04 -9.597E-04 -6.490E-04 E -2.145E-05 -7.223E-05 3.069E-07 0 -5.038E-05 -7.005E-05 F 0 -7.974E-06 -8.804E-07 0 0.000E+00 0 G 0 9.521E-06 2.693E-05 0 0 0

[0163] Figure 13 This is a configuration diagram of an imaging lens system according to the seventh embodiment of this disclosure. Figure 14 It shows Figure 13 The aberration curves of the imaging lens system are shown.

[0164] Reference Figure 13 The imaging lens system 700 may include a first lens 710, a second lens 720, a third lens 730, a fourth lens 740, a fifth lens 750, a sixth lens 760, a seventh lens 770, and an eighth lens 780.

[0165] The first lens 710 can have negative refractive power and can have a convex object-side surface and a concave image-side surface. The second lens 720 can have positive refractive power and can have a concave object-side surface and a convex image-side surface. The third lens 730 can have negative refractive power and can have a concave object-side surface and a convex image-side surface. The fourth lens 740 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The fifth lens 750 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The sixth lens 760 can have negative refractive power and can have a concave object-side surface and a concave image-side surface. The seventh lens 770 can have positive refractive power and can have a convex object-side surface and a convex image-side surface. The eighth lens 780 can have positive refractive power and can have a convex object-side surface and a concave image-side surface.

[0166] The imaging lens system 700 may further include an aperture stop ST, a filter IF, and an imaging surface IP. The aperture stop ST may be positioned between the fourth lens 740 and the fifth lens 750. The imaging surface IP may be formed on the image sensor IS, and the filter IF may be positioned between the eighth lens 780 and the imaging surface IP.

[0167] Tables 13 and 14 below show the lens characteristics and aspherical values ​​of the imaging lens system 700.

[0168] Table 13

[0169]

[0170] Table 14

[0171] Surface number S5 S6 S10 S11 S12 S14 k -2.603E+00 -4.489E+00 3.222E+01 -1.942E+01 1.058E+01 -3.785E+01 A -2.751E-01 -2.480E-01 2.007E-02 -8.888E-02 7.513E-02 3.232E-02 B 2.986E-02 4.032E-02 -1.101E-02 -3.630E-02 -3.807E-02 -1.256E-03 C -5.057E-03 -7.651E-03 -1.168E-03 1.454E-04 4.783E-03 3.722E-03 D 1.694E-04 7.026E-04 -8.446E-05 3.358E-04 7.755E-05 -1.805E-04 E -4.705E-05 -2.493E-04 3.997E-06 0 1.915E-04 2.306E-04 F 0 5.276E-05 8.086E-06 0 4.695E-05 -5.261E-05 G 0 1.231E-05 1.067E-05 0 4.843E-06 6.586E-05

[0172] Tables 15 to 17 below show the optical characteristic values ​​and conditional expression values ​​of the imaging lens systems 100 to 700 according to the first to seventh embodiments.

[0173] Table 15

[0174]

[0175] Table 16

[0176]

[0177] Table 17

[0178]

[0179] This disclosure describes an imaging lens system with certain optical characteristics (focal length) over a wide temperature range, from high-temperature environments of 80°C to low-temperature environments of -40°C.

[0180] While this disclosure includes specific examples, it will be apparent upon understanding this disclosure 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 description of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Suitable results may still be achieved if the described techniques are performed in a different order, and / or if components in the described system, architecture, device, or circuit are combined in different ways and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of this disclosure is not limited by the specific embodiments but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included in this disclosure.

Claims

1. An imaging lens system, comprising: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in order from an object side of the imaging lens system toward an image plane of the imaging lens system along an optical axis of the imaging lens system, wherein the second lens has positive refractive power, the third lens has a convex image side surface in a paraxial region thereof, the imaging lens system satisfies the following conditional expression: 0.3 < f / f4 < 0.4 wherein f is a focal length of the imaging lens system, and f4 is a focal length of the fourth lens, and the imaging lens system has eight lenses in total.

2. The imaging lens system of claim 1, wherein, the first lens has a convex object side surface in a paraxial region thereof.

3. The imaging lens system of claim 1, wherein, the second lens has a concave object side surface in a paraxial region thereof.

4. The imaging lens system of claim 1, wherein, the fourth lens has a convex object side surface in a paraxial region thereof.

5. The imaging lens system of claim 1, wherein, the fifth lens has a convex object side surface in a paraxial region thereof.

6. The imaging lens system of claim 1, wherein, the sixth lens has a convex object side surface in a paraxial region thereof.

7. The imaging lens system of claim 1, wherein, the sixth lens has a concave object side surface in a paraxial region thereof.

8. The imaging lens system of claim 1, wherein, the seventh lens has a convex object side surface in a paraxial region thereof.

9. The imaging lens system of claim 1, wherein, the eighth lens has a convex object side surface in a paraxial region thereof. 10.An imaging lens system, comprising: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in order from an object side of the imaging lens system toward an image plane of the imaging lens system along an optical axis of the imaging lens system, wherein the second lens has positive refractive power, the imaging lens system satisfies the following conditional expression: 2.0 < TTL / f4 < 3.0 wherein TTL is a distance from an object side surface of the first lens to the image plane along the optical axis, and f4 is a focal length of the fourth lens, and the imaging lens system has eight lenses in total.

11. The imaging lens system of claim 10, wherein, the object side surface of the first lens is convex in a paraxial region thereof.

12. The imaging lens system of claim 10, wherein, the second lens has a concave object side surface in a paraxial region thereof.

13. The imaging lens system of claim 10, wherein, the fourth lens has a convex object side surface in a paraxial region thereof.

14. The imaging lens system of claim 10, wherein, the fifth lens has a convex object side surface in a paraxial region thereof.

15. The imaging lens system of claim 10, wherein, the sixth lens has a convex object side surface in a paraxial region thereof.

16. The imaging lens system of claim 10, wherein, the sixth lens has a concave object side surface in a paraxial region thereof.

17. The imaging lens system of claim 10, wherein, the seventh lens has a convex object side surface in a paraxial region thereof.

18. The imaging lens system of claim 10, wherein, the eighth lens has a convex object side surface in a paraxial region thereof. 19.An imaging lens system, comprising: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in order from an object side of the imaging lens system toward an image plane of the imaging lens system along an optical axis of the imaging lens system, wherein the imaging lens system satisfies the following conditional expression: -1.6 < R3 / f4 < -0.4 wherein R3 is a radius of curvature of an object side surface of the second lens at the optical axis, and f4 is a focal length of the fourth lens, and the imaging lens system has eight lenses in total.

20. The imaging lens system of claim 19, wherein, the second lens has positive refractive power.

Images