Imaging lens system, camera module, in-vehicle system, and moving object

Abstract

The invention provides an imaging lens system, a camera module, a vehicle-mounted system, and a moving object which can realize high resolution and miniaturization. The imaging lens system comprises, in order from an object side to an image side, a first lens (L1) having a negative refractive power with a concave image-side surface facing the image side, a second lens (L2) having a negative refractive power with a concave image-side surface facing the image side, a third lens (L3) having a positive refractive power with a convex image-side surface facing the image side, and a stop (STOP). The optical system comprises a first lens (L1), a third lens (L3), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), a fourth lens (L4), a fifth lens (L5), a sixth lens (L6), a fifth lens (L5), a sixth lens (L6) and a sixth lens (L6), the object side surface of the fourth lens (L4) faces the object side, the convex surface of the fourth lens (L4) faces the object side, and the fifth lens (L5) and the sixth lens (L6) form a cemented lens, and the focal lengths of the first lens (L1), the third lens (L3) and the fourth lens (L4) are defined as f1, f3, f4 and f respectively. When the Abbe number of the d line of the fourth lens (L4) is defined as vd4, conditional expressions (1)-(4) are satisfied.

Description

Technical Field

[0001] The present invention relates to a camera lens system, a camera module, a vehicle-mounted system, and a mobile object. Background Art

[0002] In recent years, vehicle-mounted cameras and surveillance cameras installed in vehicles have been required to have sensing functions, and the resolution of imaging elements has become higher and larger. In line with this, the imaging lens system installed in vehicle-mounted cameras and the like is also on a trend of becoming larger. Specifically, there is a tendency for the aperture of the first lens (the lens closest to the object side) of the imaging lens system to become larger. For example, Patent Document 1 describes an imaging lens system composed of 6 lenses installed in a vehicle-mounted camera and the like, in which the aperture (effective diameter) of the first lens is about 3 times the diagonal length of the imaging element, resulting in a relatively large optical system.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-057562 Summary of the invention

[0006] Problems to be solved by the invention

[0007] On the other hand, in recent years, in response to the requirement for all-round sensing around the vehicle, vehicle-mounted cameras have been gradually installed in places where space is limited, such as side mirrors. Therefore, there is a demand for miniaturization of vehicle-mounted cameras. In addition, there is also a case where a vehicle-mounted camera is installed to replace a side mirror, which requires further miniaturization of the vehicle-mounted camera. The camera lens system described in Patent Document 1 is a relatively large optical system, which is difficult to meet the requirement for miniaturization of vehicle-mounted cameras.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide an imaging lens system, a camera module, an in-vehicle system, and a mobile object that can achieve high resolution and be downsized.

[0009] Means for solving problems

[0010] An imaging lens system of one embodiment includes, in order from the object side to the image side, a first lens having negative optical focal length with a concave surface on the image side facing the image side, a second lens having negative optical focal length with a concave surface on the image side facing the image side, a third lens having positive optical focal length with a convex surface on the image side facing the image side, an aperture, a fourth lens having positive optical focal length with a convex surface on the object side facing the object side, a fifth lens and a sixth lens constituting a cemented lens and having negative optical focal length on one side and positive optical focal length on the other side, wherein the focal length of the first lens is defined as f1, the focal length of the fourth lens is defined as f4, the Abbe number of the d-line of the fourth lens is defined as νd4, the focal length of the third lens is defined as f3, and the focal length of the entire optical system is defined as f, the following conditional equations (1) to (4) are satisfied.

[0011] -5.0<f1 / f<-3.0…(1)

[0012] 2.7<f4 / f<3.1…(2)

[0013] vd4>60…(3)

[0014] 6.0<f3 / f<10.0…(4)

[0015] Effects of the Invention

[0016] According to the present invention, it is possible to provide an imaging lens system, a camera module, an in-vehicle system, and a mobile object that can achieve high resolution and be downsized. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a cross-sectional view showing the structure of a camera module and an imaging lens system according to Example 1.

[0018] Figure 2A This is a diagram showing spherical aberration (longitudinal aberration) in the imaging lens system of Example 1.

[0019] Figure 2B This is a diagram showing the field curvature in the imaging lens system of Example 1.

[0020] Figure 2C 1 and 2 are diagrams showing distortion in the imaging lens system of Example 1.

[0021] Figure 2D This is a diagram showing lateral chromatic aberration in the imaging lens system of Example 1.

[0022] Figure 3 It is a cross-sectional view showing the structure of a camera module and an imaging lens system according to Example 2.

[0023] Figure 4A This is a spherical aberration diagram (longitudinal aberration diagram) in the imaging lens system of Example 2.

[0024] Figure 4B This is a diagram showing the field curvature in the imaging lens system of Example 2.

[0025] Figure 4C This is a distortion diagram in the imaging lens system of Example 2.

[0026] Figure 4D This is a diagram showing lateral chromatic aberration in the imaging lens system of Example 2.

[0027] Figure 5 1 is a cross-sectional view showing the structure of a camera module and an imaging lens system according to Example 3.

[0028] Fig. 6A This is a diagram showing spherical aberration (longitudinal aberration) in the imaging lens system of Example 3.

[0029] Figure 6B This is a diagram showing the field curvature in the imaging lens system of Example 3.

[0030] Figure 6C This is a distortion diagram of the imaging lens system of Example 3.

[0031] Fig.6D This is a diagram showing lateral chromatic aberration in the imaging lens system of Example 3.

[0032] Figure 7 1 is a cross-sectional view showing the structure of a camera module and an imaging lens system according to Example 4.

[0033] Fig. 8A This is a spherical aberration diagram (longitudinal aberration diagram) in the imaging lens system of Example 4.

[0034] Figure 8B This is a diagram showing the field curvature in the imaging lens system of Example 4.

[0035] Figure 8C This is a distortion diagram in the imaging lens system of Example 4.

[0036] Fig.8D This is a diagram showing lateral chromatic aberration in the imaging lens system of Example 4.

[0037] Fig. 9 It is a cross-sectional view showing the structure of a camera module and an imaging lens system according to Example 5.

[0038] Fig. 10A This is a diagram showing spherical aberration (longitudinal aberration) in the imaging lens system of Example 5.

[0039] Fig. 10B This is a diagram showing the field curvature in the imaging lens system of Example 5.

[0040] Fig. 10C This is a distortion diagram in the imaging lens system of Example 5.

[0041] Fig. 10D This is a diagram showing lateral chromatic aberration in the imaging lens system of Example 5.

[0042] Fig.11 This is a schematic diagram of a vehicle equipped with an in-vehicle system including a camera module according to an embodiment of the present invention.

[0043] Fig.12 It shows the composition Fig.11 A block diagram of the structure of the camera device of the vehicle-mounted system. DETAILED DESCRIPTION

[0044] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. This embodiment in particular is capable of realizing a highly reliable system in a sensing system, contributing to the development of a resilient infrastructure, with the goal of "9.1 To support economic development and human well-being focused on affordable and equitable access for all, develop high-quality, reliable, sustainable, and resilient infrastructure, including regional and cross-border infrastructure" of "9. Building a foundation for industrial and technological innovation" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0045] Furthermore, the present embodiment can further reduce the volume of the glass material used for the first lens, and can correct the aberration caused by reducing the aperture of the first lens without increasing the number of lenses constituting the imaging lens system, with the goal of "12. Ensure sustainable consumption and production patterns" of the sustainable development goals advocated by the United Nations, and "12.8 By 2030, people in all places have information and awareness related to sustainable development and a lifestyle in harmony with nature."

[0046] (Embodiment 1: Imaging Lens System)

[0047] The imaging lens system of embodiment 1 is composed of a first lens having negative power with a concave surface on the image side facing the image side, a second lens having negative power with a concave surface on the image side facing the image side, a third lens having positive power with a convex surface on the image side facing the image side, an aperture, a fourth lens having positive power with a convex surface on the object side facing the object side, a fifth lens and a sixth lens constituting a cemented lens, one of which has negative power and the other has positive power.

[0048] When the focal length of the first lens is defined as f1, the focal length of the fourth lens is defined as f4, the Abbe number of the d-line of the fourth lens is defined as νd4, the focal length of the third lens is defined as f3, and the focal length of the entire optical system is defined as f, the following conditional expressions (1) to (4) are satisfied.

[0049] -5.0<f1 / f<-3.0…(1)

[0050] 2.7<f4 / f<3.1…(2)

[0051] νd4>60…(3)

[0052] 6.0<f3 / f<10.0…(4)

[0053] This makes it possible to provide a compact imaging lens system while achieving high resolution.

[0054] Specifically, by making the optical power of the first lens relatively strong to satisfy conditional expression (1), the first lens can be made smaller in diameter, and the optical system can be made smaller in size. More specifically, when the value of f1 / f is greater than -3.0, the focal length of the first lens is too long relative to the focal length of the entire optical system. In other words, the optical power of the first lens is too weak, the aperture of the first lens becomes larger, and the imaging lens system cannot be reliably made smaller in size. On the other hand, when the value of f1 / f is less than -5.0, the focal length of the first lens is too short relative to the focal length of the entire optical system. In other words, the optical power of the first lens is too strong, and the first lens can be made smaller in diameter, but the chromatic aberration of magnification generated in the first lens is too large, and the imaging performance of the imaging lens system is deteriorated. The value of f1 / f is more preferably greater than -3.15 and less than -3.70.

[0055] In addition, by satisfying the conditional expression (2) with the focal length of the fourth lens, high resolution can be achieved more reliably. Specifically, when the value of f4 / f is greater than 3.1, the focal length of the fourth lens is too long relative to the focal length of the entire optical system. In other words, the focal length of the fourth lens is too weak, the total length of the optical system becomes longer, and the imaging lens system cannot be reliably miniaturized. On the other hand, when the value of f4 / f is less than 2.7, the focal length of the fourth lens is too short relative to the focal length of the entire optical system. In other words, the focal length of the fourth lens is too strong, the total length of the optical system becomes shorter, the error sensitivity of the imaging performance becomes higher, and manufacturing errors are easily generated. The value of f4 / f is more preferably greater than 2.75 and less than 2.95.

[0056] Furthermore, by satisfying the conditional expression (3) with the Abbe number νd4 of the fourth lens, the chromatic aberration of magnification generated in the first lens can be corrected, and high resolution can be achieved. Specifically, when the Abbe number νd4 of the fourth lens is less than 60, the chromatic aberration of magnification generated in the first lens cannot be fully corrected. The Abbe number νd4 of the fourth lens is more preferably greater than 63, and further preferably greater than 68.

[0057] In addition, by satisfying the conditional expression (4) with the focal length of the third lens, the distance from the entrance pupil to the aperture (the distance on the optical axis from the object side of the first lens to the aperture) can be shortened, and the optical system can be miniaturized. Specifically, when the value of f3 / f is greater than 10.0, the focal length of the third lens is too long relative to the focal length of the entire optical system. In other words, the focal length of the third lens is too weak, and the distance between the first lens and the aperture is enlarged, and the aperture of the first lens needs to be increased, which makes it impossible to miniaturize the imaging lens system. On the other hand, when the value of f3 / f is less than 6.0, the focal length of the third lens is too short relative to the focal length of the entire optical system. In other words, the focal length of the third lens is too strong, and the distance between the first lens and the aperture is narrowed, so that the aperture of the first lens is reduced, but the chromatic aberration of magnification generated in the first lens is too large, and the imaging performance of the imaging lens system is deteriorated. The value of f3 / f is more preferably greater than 6.5 and less than 9.5, and more preferably greater than 8.0 and less than 9.0.

[0058] Therefore, a high resolution can be achieved and a compact imaging lens system can be provided.

[0059] Furthermore, when the distance on the optical axis from the object side surface of the first lens to the image forming surface of the image sensor is defined as TTL and the focal length of the entire optical system is defined as f, the image pickup lens system preferably satisfies the following conditional expression (5).

[0060] 9<TTL<f<11…(5)

[0061] By satisfying the above-mentioned conditional formula (5), the imaging lens system can be reliably miniaturized. Specifically, when the value of TTL / f is greater than 11, the imaging lens system cannot be reliably miniaturized. On the other hand, when the value of TTL / f is less than 9, each lens needs to be miniaturized, the difficulty of manufacturing increases, the manufacturing yield deteriorates, and the component cost increases. The value of TTL / f is more preferably greater than 9.3 and less than 10.5, and further preferably greater than 9.5 and less than 10.0.

[0062] Furthermore, when the focal length of the fifth lens is defined as f5 and the focal length of the entire optical system is defined as f, the imaging lens system preferably satisfies the following conditional expression (6).

[0063] 10.0<|f5 / f|<30.0…(6)

[0064] By satisfying the above-mentioned conditional expression (6), the axial chromatic aberration caused by the use of a glass material satisfying conditional expressions (2) and (3) for the fourth lens can be properly corrected. Specifically, when the value of |f5 / f| is greater than 30.0, the optical focal length of the fifth lens is too weak to adequately correct the axial chromatic aberration, and the resolution performance of the imaging lens system is degraded. On the other hand, when the value of |f5 / f| is less than 10.0, the optical focal length of the fifth lens is too strong, the correction of the axial chromatic aberration is excessive, and the resolution performance of the imaging lens system is degraded. The value of |f5 / f| is more preferably greater than 13.0 and less than 28.5, and further preferably greater than 14.5 and less than 22.0.

[0065] In addition, when the d-line refractive index of the first lens is defined as nd1, it is preferable that the following conditional expression (7) is satisfied.

[0066] nd1>1.8…(7)

[0067] By satisfying the above conditional expression (7), the first lens can be made smaller in diameter. Specifically, when the value of nd1 is less than 1.8, the optical power of the first lens is too weak, and the first lens cannot be made smaller in diameter. The value of nd1 is more preferably greater than 1.83, and even more preferably greater than 1.84.

[0068] In addition, it is preferable that the first lens and the fourth lens are glass lenses, and the second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses.

[0069] By using a glass lens as the first lens, it is possible to provide an imaging lens system having excellent weather resistance.

[0070] In addition, by setting the fourth lens as a glass lens, it is possible to provide an imaging lens system that reduces the focus shift caused by the temperature change of the environment. Specifically, by using a glass lens in the fourth lens, it is possible to select a glass material whose temperature coefficient dnd4 / dT of the relative refractive index with respect to the d-line is less than 0 as the glass material of the fourth lens. Thus, the focus shift caused by the temperature change of the fourth lens itself can offset the change in the distance (focus shift) from the lens surface on the object side of the first lens to the imaging surface of the imaging element caused by the expansion and contraction of the lens barrel in the optical axis direction due to the temperature change of the environment. In particular, in an imaging lens system for vehicles, at high temperatures, the lens barrel extends in the optical axis direction, so that the imaging surface of the imaging element is away from the imaging lens system, but when the fourth lens becomes high temperature, the focus of the fourth lens moves toward the image side, thereby maintaining the imaging performance of the imaging lens system.

[0071] On the other hand, by using the second lens, the third lens, the fifth lens, and the sixth lens as plastic lenses, the manufacturing cost can be reduced.

[0072] Furthermore, it is preferred that the object-side surface and the image-side surface of the second lens have aspherical shapes, and the object-side surface of the second lens has an inflection point.

[0073] By reducing the aperture of the first lens, there is a disadvantage that it is difficult to adjust the relationship between the angle of view and the image height of the image formed on the imaging element (hereinafter referred to as the "angle of view characteristic"). However, by having an inflection point on the object side of the second lens, the angle of view characteristic can be easily adjusted. As a result, the reduction in the amount of peripheral light, which is a problem in wide-angle imaging lens systems, can be suppressed. Specifically, by having an inflection point on the object side of the second lens, for example, it is possible to intentionally form an image on the imaging surface in a manner that the magnification of the periphery becomes smaller, which can suppress the reduction in the amount of peripheral light.

[0074] (Implementation 2: Camera Module)

[0075] The camera module of the second embodiment comprises: the imaging lens system described above; and an imaging element disposed at the focal position of the imaging lens system and converting the light focused by the imaging lens system into an electrical signal. Thus, a high resolution can be achieved and a compact camera module can be provided.

[0076] Next, examples corresponding to the imaging lens system according to Embodiment 1 and the camera module according to Embodiment 2 will be described with reference to the drawings.

[0077] (Example 1)

[0078] Figure 1 1 is a cross-sectional view showing the structure of the camera module 10 according to Example 1. Specifically, the camera module 10 includes an imaging lens system 11 and an imaging element 12. The imaging lens system 11 and the imaging element 12 are accommodated in a housing (not shown).

[0079] The imaging element 12 is an element that converts received light into an electric signal, and for example, a CCD image sensor or a CMOS image sensor is used. The imaging element 12 is arranged at an image forming position (focal position) of the imaging lens system 11 .

[0080] The imaging lens system 11 of Example 1 includes, from the object side toward the image side, a front group Gf composed of a first lens L1, a second lens L2, and a third lens L3, an aperture stop (STOP), and a rear group Gr composed of a fourth lens L4, a fifth lens L5, and a sixth lens L6. The imaging surface of the imaging lens system 11 is represented by IMG. The first lens L1 and the fourth lens L4 are glass lenses. The second lens L2, the third lens L3, the fifth lens L5, and the sixth lens L6 are plastic lenses.

[0081] In addition, an optical filter (infrared cut filter, visible / infrared bandpass filter, etc.) is arranged between the imaging lens system 11 and the imaging element 12 as needed. In this specification, an example in which an infrared cut filter (IRCF) is arranged between the imaging lens system 11 and the imaging element 12 is described.

[0082] The first lens L1 is a glass lens with negative refractive power. The object-side surface S1 of the first lens L1 has a spherical shape with a convex surface facing the object side. The image-side surface S2 of the first lens L1 has a spherical shape with a concave surface facing the image side.

[0083] The second lens L2 is a plastic lens with negative optical power. The object side surface S3 of the second lens L2 is an aspheric shape with an inflection point. Specifically, the object side surface S3 of the second lens L2 has a shape in which the concave surface is facing the object side in the central part and the convex surface is facing the object side in the peripheral part. In addition, the image side surface S4 of the second lens L2 has an aspheric shape in which the concave surface is facing the image side.

[0084] The third lens L3 is a plastic lens with positive refractive power. The object side surface S5 of the third lens L3 has an aspheric shape with a concave surface facing the object side. In addition, the image side surface S6 of the third lens L3 has an aspheric shape with a convex surface facing the image side.

[0085] The aperture stop is an aperture that determines the F value (F number, Fno) of the lens system. The aperture stop is arranged between the third lens L3 and the fourth lens L4.

[0086] The fourth lens L4 is a glass lens having positive refractive power. The object-side surface S9 of the fourth lens L4 has a spherical shape with a convex surface facing the object side. In addition, the image-side surface S10 of the fourth lens L4 has a spherical shape with a convex surface facing the image side.

[0087] The fifth lens L5 is a plastic lens with negative refractive power. The object side surface S11 of the fifth lens L5 has an aspheric shape with a convex surface facing the object side. In addition, the image side surface S12 of the fifth lens L5 has an aspheric shape with a concave surface facing the image side.

[0088] The sixth lens L6 is a plastic lens with positive refractive power. The object-side surface S13 of the sixth lens L6 has an aspherical shape with a convex surface facing the object side. In addition, the image-side surface S14 of the sixth lens L6 has an aspherical shape with a convex surface facing the image side.

[0089] The fifth lens L5 and the sixth lens L6 form a cemented lens. That is, the image side surface S12 of the fifth lens L5 is in contact with the object side surface S13 of the sixth lens L6. The fifth lens L5 and the sixth lens L6 are cemented by an adhesive layer having an axial thickness of 0.020 mm.

[0090] The infrared cut filter (IRCF) is a filter for cutting off light in the infrared region. When designing the imaging lens system 11, the infrared cut filter is treated as an integral part of the imaging lens system 11. However, the infrared cut filter is not an essential component of the imaging lens system 11. The infrared cut filter is arranged on the image side of the sixth lens L6.

[0091] In order to prevent dust from adhering to the image pickup element 12 , a sensor protection glass may be disposed between the infrared cut filter and the image pickup element 12 .

[0092] Table 1 shows lens data of each lens surface in the imaging lens system 11 of Example 1. Table 1 shows the curvature radius (mm), the surface interval (mm) on the central optical axis, the effective diameter (mm), the refractive index nd for the d-line, and the Abbe number νd for the d-line of each surface as lens data. In Table 1, the surface with "*" indicates an aspherical surface.

[0093] [Table 1]

[0094]

[0095] The aspheric shape of the lens surface is set to z as the concave amount, c as the inverse of the radius of curvature, k as the cone coefficient, r as the height of the light from the optical axis OA, and the aspheric coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th orders are set to α4, α6, α8, α 10 , α 12 , α 14 , α 16 When , it is expressed by the following formula.

[0096] [Formula 1]

[0097]

[0098] Table 2 shows the aspheric coefficients for defining the aspheric shape of the lens surface used as an aspheric surface in the imaging lens system 11 of Example 1. In Table 2, for example, "-2.843E-03" means "-2.843×10 -3 ”. The numerical values ​​are expressed in the same way in the following tables.

[0099] [Table 2]

[0100] k <![CDATA[α4]]> <![CDATA[α6]]> <![CDATA[α8]]> Lens surface S3 0.000 3.852E-03 5.748E-04 -2.877E-05 Lens surface S4 15.871 -2.843E-03 3.386E-04 2.581E-04 Lens surface S5 0.000 -2.153E-02 2.820E-03 -1.129E-05 Lens surface S6 0.000 1.390E-03 1.677E-03 -1.432E-04 Lens surface S11 0.000 3.019E-03 -1.962E-03 1.806E-04 Lens surface S12 -0.750 5.034E-02 -2.241E-02 6.551E-03 Lens surface S13 -0.750 5.134E-02 -2.241E-02 6.551E-03 Lens surface S14 0.636 8.603E-03 -2.582E-03 1.160E-03 <![CDATA[α 10 ]]> <![CDATA[α 12 ]]> <![CDATA[α 14 ]]> <![CDATA[α 16 ]]> Lens surface S3 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Lens surface S4 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Lens surface S5 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Lens surface S6 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Lens surface S11 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Lens surface S12 -1.253E-03 1.044E-04 0.000E+00 0.000E+00 Lens surface S13 -1.253E-03 1.044E-04 0.000E+00 0.000E+00 Lens surface S14 -2.326E-04 1.971E-05 0.000E+00 0.000E+00

[0101] Next, aberrations will be described using the drawings. Figure 2A to Figure 2D Graphs showing spherical aberration (longitudinal aberration), field curvature, distortion, and lateral chromatic aberration in the imaging lens system 11 of Example 1 are shown. Figure 2A to Figure 2D As shown, in the imaging lens system 11 of Example 1, the F value is 2.0 and the half angle of view is 103°.

[0102] In addition, Figure 2A In the longitudinal aberration diagram, the horizontal axis represents the position where the light intersects the optical axis OA, and the vertical axis represents the passing height of the light on the incident pupil. Figure 2A It shows the simulation results based on the d-line, C-line and F-line.

[0103] In addition, Figure 2B In the image plane curvature diagram, the horizontal axis represents the distance in the direction of the optical axis OA, and the vertical axis represents the image height (angle of view). Figure 2B In the image plane curvature diagram, Sag represents the imaging position in the sagittal ray bundle, and Tan represents the imaging position in the meridional ray bundle. In addition, Figure 2B It shows the simulation results based on d-line.

[0104] In addition, Figure 2C In the distortion diagram, the horizontal axis represents the image distortion (%), and the vertical axis represents the image height (angle of view). Figure 2C The simulation result based on the d-line light is shown.

[0105] In addition, Figure 2D In the lateral chromatic aberration diagram of , the horizontal axis represents the amount of lateral chromatic aberration, and the vertical axis represents the image height (angle of view). Figure 2D It shows the simulation results based on the d-line, C-line and F-line.

[0106] (Example 2)

[0107] Figure 3 2 is a cross-sectional view showing a camera module 10 according to Example 2. The imaging lens system 11 according to Example 2 has the same lens structure as that of Example 1, and therefore its description is omitted. The characteristic data of the imaging lens system 11 according to Example 2 will be described below.

[0108] Table 3 shows lens data of each lens surface of the imaging lens system 11 of Example 2. The items shown in Table 3 are the same as those in Table 1, and thus their description is omitted.

[0109] [Table 3]

[0110]

[0111] Table 4 shows aspheric coefficients for defining the aspheric shape of the lens surface used as an aspheric surface in the imaging lens system 11 of Example 2. In Table 4, the aspheric shape of the lens surface is expressed by the same formula as that of Example 1.

[0112] [Table 4]

[0113] k <![CDATA[α4]]> <![CDATA[α6]]> <![CDATA[α8]]> Lens surface S3 0.000 7.406E-03 2.463E-05 -1.011E-05 Lens surface S4 13.433 2.039E-03 3.284E-03 -1.247E-03 Lens surface S5 0.000 -1.789E-02 1.192E-03 2.831E-04 Lens surface S6 0.000 4.802E-04 1.244E-03 -1.202E-04 Lens surface S11 0.000 4.001E-03 -2.442E-03 3.133E-04 Lens surface S12 -0.528 4.855E-02 -2.245E-02 6.632E-03 Lens surface S13 -0.528 4.955E-02 -2.245E-02 6.632E-03 Lens surface S14 1.406 7.425E-03 -1.810E-03 8.756E-04 <![CDATA[α 10 ]]> <![CDATA[α 12 ]]> <![CDATA[α 14 ]]> <![CDATA[α 16 ]]> Lens surface S3 5.038E-07 8.185E-09 -8.240E-11 0.000E+00 Lens surface S4 3.086E-04 5.280E-08 0.000E+00 0.000E+00 Lens surface S5 -5.453E-05 0.000E+00 0.000E+00 0.000E+00 Lens surface S6 2.168E-05 0.000E+00 0.000E+00 0.000E+00 Lens surface S11 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Lens surface S12 -1.273E-03 1.263E-04 -2.229E-06 0.000E+00 Lens surface S13 -1.273E-03 1.263E-04 -2.229E-06 0.000E+00 Lens surface S14 -1.590E-04 1.123E-05 2.416E-07 0.000E+00

[0114] Figure 4A to Figure 4D The following diagrams show spherical aberration (longitudinal aberration), field curvature, distortion, and lateral chromatic aberration in the imaging lens system 11 of Example 2. Figure 4A to Figure 4D Explanation of each aberration diagram shown Figure 2A to Figure 2D The same, therefore the description is omitted.

[0115] (Example 3)

[0116] Figure 5 2 is a cross-sectional view showing a camera module 10 according to Example 3. The imaging lens system 11 according to Example 3 has the same lens structure as that of Example 1, and therefore its description is omitted. The characteristic data of the imaging lens system 11 according to Example 3 will be described below.

[0117] Table 5 shows lens data of each lens surface of the imaging lens system 11 of Example 3. Items shown in Table 5 are the same as those in Table 1, and thus their description is omitted.

[0118] [Table 5]

[0119]

[0120] Table 6 shows aspheric coefficients for defining the aspheric shape of the lens surface used as an aspheric surface in the imaging lens system 11 of Example 3. In Table 6, the aspheric shape used for the lens surface is expressed by the same formula as that of Example 1.

[0121] [Table 6]

[0122] k <![CDATA[α4]]> <![CDATA[α6]]> <![CDATA[α8]]> Lens surface S3 0.000 8.658.E-03 -5.792.E-05 -2.095.E-05 Lens surface S4 17.480 3.714.E-03 3.144.E-03 -1.028.E-03 Lens surface S5 0.000 -1.417.E-02 1.736.E-03 2.727.E-04 Lens surface S6 0.000 1.049.E-03 1.527.E-03 -2.179.E-04 Lens surface S11 0.000 3.601.E-03 -2.549.E-03 2.955.E-04 Lens surface S12 -0.525 4.806.E-02 -2.181.E-02 5.834.E-03 Lens surface S13 -0.525 5.106.E-02 -2.181.E-02 5.834.E-03 Lens surface S14 1.931 8.563.E-03 -1.785.E-03 8.627.E-04 <![CDATA[α 10 ]]> <![CDATA[α 12 ]]> <![CDATA[α 14 ]]> <![CDATA[α 16 ]]> Lens surface S3 9.016.E-07 1.984.E-07 -1.524.E-08 0.000.E+00 Lens surface S4 2.521.E-04 -7.920.E-06 0.000.E+00 0.000.E+00 Lens surface S5 -9.299.E-05 9.812.E-06 0.000.E+00 0.000.E+00 Lens surface S6 2.727.E-05 4.926.E-07 0.000.E+00 0.000.E+00 Lens surface S11 0.000.E+00 0.000.E+00 0.000.E+00 0.000.E+00 Lens surface S12 -1.217.E-03 1.479.E-04 -5.646.E-06 0.000.E+00 Lens surface S13 -1.217.E-03 1.479.E-04 -5.646.E-06 0.000.E+00 Lens surface S14 -1.459.E-04 1.268.E-05 -2.869.E-08 0.000.E+00

[0123] Figure 6A to Figure 6D The following are diagrams showing spherical aberration (longitudinal aberration), field curvature, distortion, and lateral chromatic aberration in the imaging lens system 11 of Example 3. Figure 6A to Figure 6D Explanation of each aberration diagram shown Figure 2A to Figure 2D The same, therefore the description is omitted.

[0124] (Example 4)

[0125] Figure 7 2 is a cross-sectional view showing a camera module 10 according to Example 4. The imaging lens system 11 according to Example 4 has the same lens structure as that of Example 1, and therefore its description is omitted. The characteristic data of the imaging lens system 11 according to Example 4 will be described below.

[0126] Table 7 shows lens data of each lens surface of the imaging lens system 11 of Example 4. Items shown in Table 7 are the same as those in Table 1, and thus their description is omitted.

[0127] [Table 7]

[0128]

[0129] Table 8 shows aspheric coefficients for defining the aspheric shape of the lens surface used as an aspheric surface in the imaging lens system 11 of Example 4. In Table 8, the aspheric shape used for the lens surface is expressed by the same formula as that of Example 1.

[0130] [Table 8]

[0131] k <![CDATA[α4]]> <![CDATA[α6]]> <![CDATA[α8]]> Lens surface S3 0.000 8.875.E-03 1.515.E-04 -4.084.E-05 Lens surface S4 35.853 5.677.E-03 1.253.E-03 1.704.E-04 Lens surface S5 0.000 -1.267.E-02 1.460.E-03 6.693.E-04 Lens surface S6 0.000 1.376.E-03 1.757.E-03 -4.855.E-04 Lens surface S11 0.000 2.717.E-03 -1.791.E-03 2.010.E-04 Lens surface S12 -0.509 3.444.E-02 -1.320.E-02 2.911.E-03 Lens surface S13 -0.509 3.744.E-02 -1.320.E-02 2.911.E-03 Lens surface S14 2.034 7.543.E-03 -1.578.E-03 7.097.E-04 <![CDATA[α 10 ]]> <![CDATA[α 12 ]]> <![CDATA[α 14 ]]> <![CDATA[α 16 ]]> Lens surface S3 -7.588.E-07 5.511.E-07 -2.786.E-08 0.000.E+00 Lens surface S4 -4.289.E-05 1.167.E-05 0.000.E+00 0.000.E+00 Lens surface S5 -2.982.E-04 4.916.E-05 0.000.E+00 0.000.E+00 Lens surface S6 1.240.E-04 -1.213.E-05 0.000.E+00 0.000.E+00 Lens surface S11 -1.214.E-05 2.270.E-06 0.000.E+00 0.000.E+00 Lens surface S12 -8.012.E-04 1.593.E-04 -1.294.E-05 0.000.E+00 Lens surface S13 -8.012.E-04 1.593.E-04 -1.294.E-05 0.000.E+00 Lens surface S14 -1.081.E-04 7.424.E-06 1.855.E-07 0.000.E+00

[0132] Figures 8A to 8D The following are diagrams showing spherical aberration (longitudinal aberration), field curvature, distortion, and lateral chromatic aberration in the imaging lens system 11 of Example 4. Figures 8A to 8D Explanation of each aberration diagram shown Figure 2A to Figure 2D The same, therefore the description is omitted.

[0133] (Example 5)

[0134] Fig. 9 1 is a cross-sectional view of the camera module 10 of Example 5. The difference between the imaging lens system 11 of Example 5 and Example 1 is that the object side surface S3 of the second lens L2 has a convex shape on the object side. The other structures of the imaging lens system 11 of Example 5 have the same lens structure as that of Example 1, so the description thereof is omitted. The characteristic data of the imaging lens system 11 of Example 5 is described below.

[0135] Table 9 shows lens data of each lens surface of the imaging lens system 11 of Example 5. Items shown in Table 9 are the same as those in Table 1, and thus their description is omitted.

[0136] [Table 9]

[0137]

[0138] Table 10 shows aspheric coefficients for defining the aspheric shape of the lens surface used as an aspheric surface in the imaging lens system 11 of Example 5. In Table 10, the aspheric shape used for the lens surface is expressed by the same formula as that of Example 1.

[0139] [Table 10]

[0140] k <![CDATA[α4]]> <![CDATA[α6]]> <![CDATA[α8]]> Lens surface S3 0.000 6.144.E-03 -3.704.E-04 4.449.E-05 Lens surface S4 1.041 1.956.E-03 -3.789.E-03 3.982.E-03 Lens surface S5 0.000 -1.742.E-02 1.134.E-05 9.424.E-04 Lens surface S6 0.000 -3.194.E-04 2.989.E-03 -1.212.E-03 Lens surface S11 0.000 1.172.E-03 -2.383.E-03 2.229.E-04 Lens surface S12 -0.008 4.650.E-02 -2.129.E-02 7.526.E-03 Lens surface S13 -0.008 4.950.E-02 -2.129.E-02 7.526.E-03 Lens surface S14 1.198 7.399.E-03 -2.659.E-03 1.288.E-03 <![CDATA[α 10 ]]> <![CDATA[α 12 ]]> <![CDATA[α 14 ]]> <![CDATA[α 16 ]]> Lens surface S3 -3.615.E-06 4.405.E-07 -1.404.E-08 0.000.E+00 Lens surface S4 -1.908.E-03 3.378.E-04 0.000.E+00 0.000.E+00 Lens surface S5 -3.688.E-04 4.843.E-05 0.000.E+00 0.000.E+00 Lens surface S6 3.230.E-04 -3.357.E-05 0.000.E+00 0.000.E+00 Lens surface S11 -1.607.E-05 -7.994.E-07 0.000.E+00 0.000.E+00 Lens surface S12 -2.680.E-03 5.368.E-04 -4.806.E-05 0.000.E+00 Lens surface S13 -2.6680.E-03 5.368.E-04 -4.806.E-05 0.000.E+00 Lens surface S14 -2.957.E-04 3.181.E-05 -8.650.E-07 0.000.E+00

[0141] FIG. 10A to FIG. 10D The following are diagrams showing spherical aberration (longitudinal aberration), field curvature, distortion, and lateral chromatic aberration in the imaging lens system 11 of Example 5. FIG. 10A to FIG. 10D Explanation of each aberration diagram shown Figure 2A to Figure 2D The same, therefore the description is omitted.

[0142] Table 11 shows the total optical length TTL of the imaging lens system 11, the focal length f of the entire optical system of the imaging lens system 11, the focal length f1 of the first lens L1, the focal length f2 of the second lens L2, the focal length f3 of the third lens L3, the focal length f4 of the fourth lens L4, the focal length f5 of the fifth lens L5, the focal length f6 of the sixth lens L6, the value of f1 / f, the value of f2 / f, the value of f3 / f, the value of f4 / f, the value of f5 / f, the value of f6 / f, the value of TTL / f, the d-line refractive index nd1 of the first lens L1, and the Abbe number νd4 of the d-line of the fourth lens. In Table 11, the units of the focal length and the total optical length are all mm. In addition, the focal length and the total length shown in Table 11 are calculated using light with a wavelength of 550 nm.

[0143] [Table 11]

[0144] Example 1 Example 2 Example 3 Example 4 Example 5 Optical full length TTL 16.105 15.823 16.469 16.746 16.001 Focal length f 1.727 1.727 1.724 1.751 1.503 f1 -5.279 -5.485 -5.432 -5.602 -5.519 f2 -6.555 -6.533 -6.961 -7.389 -5.202 f3 10.636 14.735 16.195 17.100 9.976 f4 4.674 4.781 4.921 5.103 4.210 f5 -25.302 -34.703 -37.346 -49.824 -20.591 f6 8.488 7.847 7.439 7.785 8.276 f1 / f -3.057 -3.176 -3.151 -3.199 -3.671 f2 / f -3.796 -3.782 -4.038 -4.220 -3.460 f3 / f 6.159 8.530 9.394 9.765 6.637 f4 / f 2.707 2.768 2.854 2.914 2.801 f5 / f -14.652 -20.090 -21.663 -28.453 -13.699 f6 / f 4.915 4.543 4.315 4.446 5.506 TTL / f 9.326 9.160 9.553 9.563 10.645 nd1 1.840 1.839 1.839 1.840 1.839 νd4 68.624 68.624 68.624 63.406 63.406

[0145] In Examples 1 to 5, by making the optical power of the first lens L1 relatively strong to satisfy conditional expression (1), it is possible to reduce the aperture of the first lens L1, thereby miniaturizing the optical system. Specifically, since the value of f1 / f is less than -3.0, the aperture of the first lens can be reduced, and the imaging lens system can be reliably miniaturized. Furthermore, since the value of f1 / f is greater than -5.0, the chromatic aberration of magnification generated in the first lens L1 is suppressed within an appropriate range, and deterioration of the imaging performance of the imaging lens system 11 can be avoided. In fact, in Examples 1 to 5, as shown in FIG. Figure 2D , Figure 4D , Fig.6D , Fig.8D , Fig. 10D As shown, the chromatic aberration of magnification can be appropriately reduced.

[0146] In addition, by making the optical power of the fourth lens L4 satisfy the conditional expression (2), high resolution can be achieved more reliably. Specifically, since the value of f4 / f is greater than 2.7, it is possible to prevent the error sensitivity of the imaging performance from becoming high, and it is possible to avoid the easy occurrence of manufacturing errors. In addition, since the value of f4 / f is less than 3.1, it is possible to avoid the total length of the optical system from becoming longer, and it is possible to reliably miniaturize the imaging lens system 11.

[0147] Furthermore, by satisfying the conditional expression (3) with the Abbe number νd4 of the fourth lens L4, the chromatic aberration of magnification generated in the first lens L1 can be corrected, and high resolution can be achieved. Figure 2D , Figure 4D , Fig.6D , Fig.8D , Fig. 10D As shown, the chromatic aberration of magnification can be appropriately reduced.

[0148] Furthermore, by making the focal length of the third lens L3 satisfy conditional expression (4), the distance from the incident pupil to the aperture can be shortened, and the optical system can be miniaturized. Specifically, since the value of f3 / f is less than 10.0, the distance between the first lens L1 and the aperture can be prevented from expanding, the first lens L1 can be made smaller in diameter, and the imaging lens system 11 can be miniaturized. In addition, since the value of f3 / f is greater than 6.0, the chromatic aberration of magnification generated in the first lens L1 can be suppressed from becoming excessive, and the deterioration of the imaging performance of the imaging lens system 11 can be avoided. Therefore, high resolution can be achieved, and a miniaturized imaging lens system 11 can be provided. In fact, in the imaging lens system 11 of Examples 1 to 5, the aperture (effective diameter) of the first lens L1 is less than about twice the diagonal length of the imaging element 12, thereby miniaturizing the imaging lens system 11. In addition, as Figure 2A to Figure 2D , Figure 4A to Figure 4D , Figure 6A to Figure 6D , Figures 8A to 8D , FIG. 10A to FIG. 10D As shown, the imaging lens system 11 of Examples 1 to 5 appropriately reduces spherical aberration, field curvature, distortion, and lateral chromatic aberration, and has excellent imaging performance and can achieve high resolution.

[0149] In Examples 1 to 5, the imaging lens system 11 satisfies the above-mentioned conditional expression (5). This makes it possible to reliably reduce the size of the imaging lens system.

[0150] In Examples 1 to 5, the imaging lens system 11 satisfies the above-mentioned conditional expression (6). Thus, the axial chromatic aberration caused by the fourth lens L4 can be appropriately corrected. Figure 2A to Figure 2D , Figure 4A to Figure 4D , Figure 6A to Figure 6D , Figures 8A to 8D , FIG. 10A to FIG. 10D As shown, spherical aberration, field curvature, and distortion aberration are appropriately reduced, imaging performance is excellent, and high resolution can be achieved.

[0151] In Examples 1 to 5, the imaging lens system 11 satisfies the above-mentioned conditional expression (7). This makes it possible to reduce the diameter of the first lens L1.

[0152] In addition, in Examples 1 to 5, the first lens L1 and the fourth lens L4 are glass lenses, and the second lens L2, the third lens L3, the fifth lens L5, and the sixth lens L6 are plastic lenses. By setting the first lens L1 to a glass lens, it is possible to provide an imaging lens system 11 with excellent weather resistance. In addition, by setting the fourth lens L4 to a glass lens, it is possible to provide an imaging lens system 11 that reduces the focus shift caused by changes in environmental temperature. Table 12 shows the focus shift amount (μm) associated with the change in environmental temperature of the focal length f of the imaging lens system 11 of Examples 1 to 5. Table 12 shows the focus shift amount from the focal length f at a normal temperature of 25°C. In addition, the material of the tube and the shell used in the calculation of the focus shift amount of the focal length f shown in Table 10 is RenyXL1027U manufactured by Mitsubishi Engineering-Plastics Corporation.

[0153] [Table 12]

[0154]

[0155] Furthermore, by using the second lens L2, the third lens L3, the fifth lens L5, and the sixth lens L6 as plastic lenses, the manufacturing cost can be reduced.

[0156] In Examples 1 to 5, the object side surface S3 and the image side surface S4 of the second lens L2 have aspherical shapes, and the object side surface S3 of the second lens L2 has an inflection point. This makes it easy to adjust the field angle characteristics and can suppress the reduction in peripheral light that is a problem in wide-angle imaging lens systems.

[0157] Furthermore, the camera module 10 includes the imaging lens system 11 , which is compact and has a sufficient resolution required for image recognition in autonomous driving, thereby enabling compactness of the camera module 10 and high-precision sensing.

[0158] (Implementation method 3)

[0159] Fig.11 1 is a schematic diagram of a vehicle 40 equipped with a vehicle-mounted system having an imaging device 50, the imaging device 50 including an imaging lens system 11 of Embodiment 1 or Embodiment 2 and an imaging element 12 that converts light focused by the imaging lens system 11 into an electrical signal. As shown in the figure, the imaging device 50 can be mounted on the vehicle 40. Fig.11This is an example of the configuration of the mounting position of the camera device 50 in the vehicle 40. The camera device 50 mounted on the vehicle 40 can also be called a vehicle-mounted camera and can be installed in various places in the vehicle 40. For example, the first camera device 50a can also be configured on the front bumper or its vicinity as a camera for monitoring the front of the vehicle 40 when it is traveling. In addition, the second camera device 50b that monitors the front can also be configured near the interior mirror (Inner Rearview Mirror) in the cabin of the vehicle 40. The third camera device 50c can also be configured on the dashboard or in the instrument panel as a camera for monitoring the driving condition of the driver. The fourth camera device 50d can also be set at the rear of the vehicle 40 for the purpose of a rear monitor of the vehicle 40. The camera devices 50a and 50b can be called front cameras. The third camera device 50c can be called a built-in camera. The fourth camera device 50d can be called a rear camera. The camera device 50 is not limited thereto, and includes a camera device installed at various positions, such as a left camera for photographing the left rear side and a right camera for photographing the right rear side.

[0160] The image signal of the image captured by the camera device 50 can be output to the information processing device 42 and / or the display device 43 in the vehicle 40. These information processing devices 42 and the display device 43 constitute the vehicle-mounted system together with the camera device 50. The information processing device 42 in the vehicle 40 includes a device that processes the image signal obtained by the camera device 50, recognizes various objects in the captured image, and assists the driver in driving. In addition, the information processing device 42 includes, for example, a navigation device, a collision damage reduction braking device, a vehicle distance control device, and a lane departure warning device, but is not limited to this. The display device 43 displays the image processed and output by the information processing device 42, but can also directly receive the image signal from the camera device 50. In addition, the display device 43 can adopt a liquid crystal display (LCD: Liquid Crystal Display), an organic EL (Electro-Luminescence: Electroluminescence) display, and an inorganic EL display, but is not limited to this. The display device 43 can display the image signal output from the camera device 50 that captures an image of a position that is difficult for the driver to visually recognize, such as a rear camera, to the driver and other passengers.

[0161] Fig.12 Shows the composition Fig.11 As shown in the figure, the imaging device 50 of one embodiment includes a control unit 52, a storage unit 54, and a camera module 10.

[0162] The control unit 52 controls the camera module 10 and processes the electrical signal output from the imaging element 12 of the camera module 10. The control unit 52 may be configured as a processor, for example. In addition, the control unit 52 may include one or more processors. The processor may also include a general-purpose processor that reads a specific program to perform a specific function, and a dedicated processor dedicated to a specific process. A dedicated processor may include a dedicated IC (Integrated Circuit). A dedicated IC is also called an ASIC (Application Specific Integrated Circuit). The processor may include a programmable logic device. A programmable logic device is also called a PLD (Programmable Logic Device). A PLD may include an FPGA (Field-Programmable Gate Array). The control unit 52 may also be any one of a SoC (System-on-a-Chip) and a SiP (System In a Package) in which one or more processors cooperate.

[0163] The storage unit 54 stores various information or parameters related to the operation of the camera device 50. The storage unit 54 may be composed of, for example, a semiconductor memory or the like. The storage unit 54 may also function as a working memory of the control unit 52. The storage unit 54 may also store captured images. The storage unit 54 may also store various parameters used by the control unit 52 to perform detection processing based on captured images. The storage unit 54 may also be included in the control unit 52.

[0164] As described above, the camera module 10 captures a subject image formed by the imaging lens system 11 through the imaging element 12, and outputs the captured image. The image captured by the camera module 10 is also referred to as a captured image.

[0165] The imaging element 12 may be composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device). The imaging element 12 has a photographing surface on which a plurality of pixels are arranged. Each pixel outputs a signal determined by a current or a voltage according to the amount of incident light. The signal output by each pixel is also referred to as photographing data.

[0166] The shooting data may be read out by the camera module 10 for all pixels and taken into the control unit 52 as a shot image. The shot image read out for all pixels is also called a maximum shot image. The shooting data may be read out by the camera module 10 for a part of the pixels and taken in as a shot image. In other words, the shooting data may be read out from pixels in a predetermined take-in range. The shooting data read out from pixels in a predetermined take-in range may be taken in as a shot image. The predetermined take-in range may also be set by the control unit 52. The camera module 10 may also obtain a predetermined take-in range from the control unit 52. The imaging element 12 may also capture an image of a predetermined take-in range in the subject image formed by the imaging lens system 11.

[0167] In addition, the present invention is not limited to the above-mentioned embodiments, and can be appropriately modified without departing from the scope of the present invention. For example, the use of the imaging lens system of the present invention is not limited to vehicle-mounted cameras and surveillance cameras, but can also be used for other purposes such as being mounted on small electronic devices such as mobile phones.

[0168] This application claims the benefit of priority based on Japanese patent application No. 2022-113780 filed on July 15, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

[0169] Industrial Applicability

[0170] A camera lens system, a camera module, an in-vehicle system, and a mobile object can be provided which can realize high resolution and be miniaturized.

[0171] Explanation of symbols

[0172] 10 camera modules,

[0173] 11 Camera lens system,

[0174] 12 camera components,

[0175] 40 Vehicles (mobile objects),

[0176] 42 information processing device (processing device),

[0177] 43 display device (output device),

[0178] 50 camera device,

[0179] 52 Control Department,

[0180] L1 first lens,

[0181] L2 second lens,

[0182] L3 third lens,

[0183] L4 fourth lens,

[0184] L5 fifth lens,

[0185] L6 sixth lens,

[0186] STOP aperture,

[0187] Gf front group,

[0188] Gr group,

[0189] IRCF infrared cut-off filter,

[0190] IMG imaging surface,

[0191] OA optical axis.

Claims

1. A camera lens system, characterized in that: The lens system includes, from the object side to the image side, a first lens having negative power with its image side facing the concave surface toward the image side; a second lens having negative power with its image side facing the concave surface toward the image side; a third lens having positive power with its image side facing the convex surface toward the image side; a stop; a fourth lens having positive power with its object side facing the convex surface toward the object side; and a fifth lens and a sixth lens constituting a cemented lens, one of which has negative power and the other has positive power. When the focal length of the first lens is defined as f1, the focal length of the fourth lens is defined as f4, the Abbe number of the d-line of the fourth lens is defined as νd4, the focal length of the third lens is defined as f3, and the focal length of the entire optical system is defined as f, the following conditional expressions (1) to (4) are satisfied: -5.0 <f1 / f<-3.0…(1) 2.7 <f4 / f<3.1…(2) vd4>60…(3) 6.0 <f3 / f<10.0…(4)。 2. The imaging lens system according to claim 1, wherein: When the distance on the optical axis from the object side surface of the first lens to the imaging surface of the imaging element is defined as TTL and the focal length of the entire optical system is defined as f, the following conditional expression (5) is satisfied: 9<TTL / f<11…(5).

3. The imaging lens system according to claim 1, wherein: When the focal length of the fifth lens is defined as f5 and the focal length of the entire optical system is defined as f, the following conditional formula (6) is satisfied: 10.00<|f5 / f|<30.0…(6).

4. The imaging lens system according to claim 2, wherein: When the focal length of the fifth lens is defined as f5 and the focal length of the entire optical system is defined as f, the following conditional formula (6) is satisfied: 10.0<|f5 / f|<30.0…(6).

5. The imaging lens system according to claim 1, wherein: When the d-line refractive index of the first lens is defined as nd1, the following conditional formula (7) is satisfied: nd1>1,8…(7).

6. The imaging lens system according to claim 2, wherein: When the d-line refractive index of the first lens is defined as nd1, the following conditional formula (7) is satisfied: nd1>1.8…(7).

7. The imaging lens system according to claim 3, wherein: When the d-line refractive index of the first lens is defined as nd1, the following conditional formula (7) is satisfied: nd1>1.8…(7).

8. The imaging lens system according to claim 1, wherein: The first lens and the fourth lens are glass lenses, The second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses.

9. The imaging lens system according to claim 2, wherein: The first lens and the fourth lens are glass lenses, The second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses.

10. The imaging lens system according to claim 3, wherein: The first lens and the fourth lens are glass lenses, The second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses.

11. The imaging lens system according to claim 5, wherein: The first lens and the fourth lens are glass lenses, The second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses.

12. The imaging lens system according to claim 1, wherein: The object-side surface and the image-side surface of the second lens have aspherical shapes, and the object-side surface of the second lens has an inflection point.

13. The imaging lens system according to claim 2, wherein: The object-side surface and the image-side surface of the second lens have aspherical shapes, and the object-side surface of the second lens has an inflection point.

14. The imaging lens system according to claim 3, wherein: The object-side surface and the image-side surface of the second lens have aspherical shapes, and the object-side surface of the second lens has an inflection point.

15. The imaging lens system according to claim 5, wherein: The object-side surface and the image-side surface of the second lens have aspherical shapes, and the object-side surface of the second lens has an inflection point.

16. The imaging lens system according to claim 8, wherein: The object-side surface and the image-side surface of the second lens have aspherical shapes, and the object-side surface of the second lens has an inflection point.

17. A camera module, characterized in that: have: The imaging lens system according to any one of claims 1 to 16; and An imaging element that converts the light focused by the imaging lens system into an electrical signal.

18. A vehicle-mounted system, mounted on a vehicle, characterized in that: The vehicle-mounted system comprises: The camera module of claim 17; and An information processing device processes a captured image output from the imaging element of the camera module to recognize an object in the captured image.

19. A mobile object equipped with the vehicle-mounted system according to claim 18, characterized in that: The vehicle-mounted system further includes an output device for outputting information to the occupants. The information processing device is configured to output the identification information of the object to the output device.

Images