Imaging lens system and camera module including same, imaging device, in-vehicle system, and mobile body

Abstract

To provide a lightweight and bright imaging lens system having high resolution corresponding to a wide field of view. [Solution] In an imaging lens system composed of, in order from the object side to the image side, a front group and a rear group, the front group is composed of a first lens having negative refractive power with a concave surface facing the image side, and a second lens, the rear group is composed of a third lens having positive refractive power, a fourth lens having positive refractive power, a fifth lens having negative refractive power with a concave surface facing the image side, and a sixth lens having positive refractive power, the first lens and the third lens are glass lenses, the second lens is a plastic lens, the fourth lens forms a cemented lens cemented with the fifth lens, and when the focal length of the first lens is f1 and the focal length of the second lens is f2, |f2 / f1|>10 is satisfied.

Description

[Technical Field]

[0001] The present invention relates to an imaging lens system, and a camera module, an imaging device, an in-vehicle system, and a moving body that include the imaging lens system. [Background technology]

[0002] In recent years, there has been a demand for lenses with a wide field of view as imaging lens systems for on-board use in automobiles, such as imaging lens systems used in on-board cameras for sensing purposes to check the front, back, and sides of a vehicle in order to ensure safety when driving.

[0003] Imaging lens systems for vehicle-mounted cameras are required to have an extremely wide field of view, high resolution, and high brightness, without being subject to focus shifts due to temperature changes or vibrations caused by vehicle travel. Furthermore, imaging lens systems for vehicle-mounted cameras are also required to be lightweight, compact (small), and low-cost. Patent Document 1 describes an imaging lens system for a vehicle-mounted camera. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-101146 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above-mentioned problems, and provides a lightweight and bright imaging lens system that has high resolving power corresponding to a wide field of view. [Means for solving the problem]

[0006] In an imaging lens system which is composed of, in order from the object side to the image side, a front group and a rear group, the front group is composed of a first lens having negative refractive power with a concave surface facing the image side, and a second lens, the rear group is composed of a third lens having positive refractive power, a fourth lens having positive refractive power, a fifth lens having negative refractive power with a concave surface facing the image side, and a sixth lens having positive refractive power, the first lens and the third lens are glass lenses, the second lens is a plastic lens, the fourth lens forms a cemented lens cemented with the fifth lens, and when the focal length of the first lens is f1 and the focal length of the second lens is f2, |f2 / f1|>10 is satisfied. [Effects of the Invention]

[0007] The present invention can provide a lighter, brighter imaging lens system with high resolution corresponding to a wide field of view. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of an imaging lens system according to a first embodiment. [Figure 2] 3A to 3C are aberration diagrams of the imaging lens system according to Example 1. [Figure 3] FIG. 10 is a cross-sectional view of an imaging lens system according to a second embodiment. [Figure 4] 10A to 10C are aberration diagrams of the imaging lens system according to Example 2. [Figure 5] FIG. 10 is a cross-sectional view of an imaging lens system according to a third embodiment. [Figure 6] 10A to 10C are aberration diagrams of an imaging lens system according to Example 3. [Figure 7] FIG. 10 is a cross-sectional view of an imaging lens system according to a fourth embodiment. [Figure 8] 10A to 10C are aberration diagrams of an imaging lens system according to Example 4. [Figure 9] FIG. 1 is a diagram illustrating the configuration of an imaging device equipped with an imaging lens system. [Figure 10] FIG. 1 is a schematic diagram of a vehicle equipped with an imaging device. [Figure 11] FIG. 1 is a diagram illustrating the configuration of a vehicle equipped with an imaging device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. In the drawings and descriptions of the present embodiments, functionally identical elements may be indicated by the same numbers. Note that the following description shows an embodiment based on the principles, but this is intended to help understand the present embodiment and is not to be used to interpret the present embodiment in a restrictive manner. The description of the present embodiment is merely a typical example and does not limit the scope of the claims or application examples in any sense.

[0010] Although the present embodiment has been described in sufficient detail for those skilled in the art to practice it, it should be understood that other embodiments are possible, and that changes in configuration and structure and substitutions of various elements are possible without departing from the scope and spirit of the technical concept. Therefore, the following description should not be interpreted as limiting.

[0011] Furthermore, this embodiment can realize a highly reliable system, particularly in a sensing system, and contribute to the development of resilient infrastructure, and targets "9.1 Develop quality, reliable, sustainable and resilient infrastructure, including regional and transborder infrastructure, to support economic development and human well-being, with a focus on affordable and equitable access for all," in "9. Industry, innovation and infrastructure" of the Sustainable Development Goals (SDGs) advocated by the United Nations. [Embodiment 1] As an embodiment, an imaging lens system 11 of a camera module 10 will be described.

[0012] [Example 1] Fig. 1 is a cross-sectional view showing the configuration of an imaging lens system 11 of a camera module 10 of Example 1. As shown in Fig. 1, the imaging lens system 11 of Example 1 includes, in order along an optical axis O direction from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6. The imaging lens system 11 also includes a front group that determines the angle of view characteristics by the first lens L1 and the second lens L2, and a rear group that contributes to brightness and light-gathering characteristics by the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 across an aperture 1.

[0013] The first lens L1 has a lens surface S1 having a convex shape on the object side and a lens surface S2 having a concave shape on the image side. The first lens L1 is a meniscus glass lens having negative refractive power.

[0014] The second lens L2 has a lens surface S3 having a concave shape on the object side and a lens surface S4 having a convex shape on the image side. The second lens L2 is a plastic lens having a meniscus shape and negative refractive power.

[0015] The diaphragm 1 (STOP) has an opening on the diaphragm surface S5 that allows light rays to pass through, and the diameter of the opening determines the amount of light that enters the optical system. The diaphragm 1 is a thin, non-transparent material.

[0016] The third lens L3 has a lens surface S6 having a convex shape facing the object side and a lens surface S7 having a convex shape facing the image side. The third lens L3 is a glass lens having positive refractive power.

[0017] The fourth lens L4 has a lens surface S8 having a convex shape facing the object side and a lens surface S9 having a convex shape facing the image side. The fourth lens L4 has positive refractive power.

[0018] The fifth lens L5 has a surface having a concave shape on the object side and a lens surface S10 having a concave shape on the image side. The fifth lens L5 has negative refractive power.

[0019] The fourth lens L4 and the fifth lens L5 form a cemented lens by bonding the image-side surface of the fourth lens L4 and the object-side surface of the fifth lens L5 together with a synthetic resin adhesive or the like. Furthermore, the periphery and edge of the cemented portion of the cemented lens may be coated with a solventless resin mixed with carbon black or the like. In Example 1, the cemented lens has positive refractive power.

[0020] The sixth lens L6 has an aspherical lens surface S11 with a convex shape facing the object side and a positive curvature, and an aspherical lens surface S12 with a concave shape facing the image side and a positive curvature. The sixth lens L6 is a meniscus lens with positive refractive power.

[0021] The fourth lens L4, the fifth lens L5, and the sixth lens L6 are plastic lenses, but they may also be glass lenses. That is, by using plastic lenses for the second lens L2, the fourth lens L4, the fifth lens L5, and the sixth lens L6 in the imaging lens system 11, weight and cost can be reduced. Furthermore, the imaging lens system 11 has more lenses in the rear group than in the front group, and by using more plastic lenses in the rear group, the center of gravity of the imaging lens system 11 is closer to the center in the direction of the optical axis O, thereby stabilizing the weight balance. Furthermore, by setting the power balance between the glass lenses and the plastic lenses, focus fluctuations due to changes in environmental temperature, which are required for in-vehicle camera lenses, etc., can be suppressed.

[0022] Furthermore, similar to the lens surface S2 of the first lens L1, each of the lens surfaces of the first lens L1 to the sixth lens L6 may have a curved effective surface passing through the optical axis O, and the edge side may be flat.

[0023] The IR cut filter 14 (IRCF) is a filter that removes IR (infrared light) from light rays. The IR cut filter 14 has IRCF surfaces S13 and S14. The cover glass 13 (CG) is a glass plate that protects the imaging element 12. The cover glass 13 has CG surfaces S15 and S16. The imaging element 12 (IMG) is an element that captures a light image of an object formed by the imaging lens system 11, and has an imaging surface S17. Note that the IR cut filter 14 and the cover glass 13 are not essential components of the imaging lens system 11.

[0024] As described above, the camera module 10 includes the imaging lens system 11, the aperture 1, the IR cut filter 14, the cover glass 13, and the imaging element 12, and is fixed to the camera module 10 or the housing of the imaging lens system 11 by a flange or the like. Note that the IR cut filter 14 and the cover glass 13 are not essential components of the camera module 10. Furthermore, although the aperture 1 is provided integrally with the imaging lens system 11, it is not an essential component of the imaging lens system 11, and the aperture 1 need not be provided. Furthermore, the aperture 1 is provided between the second lens L2 and the third lens L3, but may be provided at any position between the first lens L1 to the sixth lens L6. Furthermore, the imaging lens system 11 may be provided with multiple apertures.

[0025] Table 1 shows lens data for each lens surface of the imaging lens system 11 of the first embodiment.

[0026] [Table 1]

[0027] The lens data table in Table 1 shows the paraxial radius of curvature R, surface spacing D, refractive index Nd, and Abbe number vd for each surface. Note that surface spacing D(i) is the distance between surfaces S(i) and S(i+1) on the optical axis O. For example, this indicates that the center thickness on the optical axis O, which is the distance between the object-side lens surface S1 and the image-side lens surface S2, is 1.111 mm. Furthermore, surfaces marked with an "*" (for example, lens surface S3 of the second lens L2) are aspherical. The aspherical shape used for the aspherical lens surfaces in Table 1 is expressed by equation 1.

[0028]

number

[0029] where Z is the amount of sag, c is the reciprocal of the paraxial radius of curvature R, k is the conic coefficient, and r is the height from the optical axis. A4, A6, A8, A10, A12, A14, and A16 are the 4th-order, 6th-order, 8th-order, 10th-order, 12th-order, 14th-order, and 16th-order aspheric coefficients, respectively.

[0030] Table 2 shows aspherical coefficients and the like for defining the aspherical shape of the lens surfaces designated as aspherical in Table 1 in the imaging lens system 11 of the first embodiment.

[0031] [Table 2]

[0032] In Table 2, for example, "-7.59032E-03" means "-7.59032×10^-3".

[0033] Table 3 shows the characteristic values ​​of the imaging lens system 11 of Example 1 shown in Tables 1, 2, etc.

[0034] [Table 3]

[0035] In the imaging lens system 11, f1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, f3 is the focal length of the third lens L3, f4 is the focal length of the fourth lens L4, f5 is the focal length of the fifth lens L5, and f6 is the focal length of the sixth lens L6. f is the focal length of the entire lens system from the first lens L1 to the sixth lens L6.

[0036] Furthermore, FGF indicates the composite focal length of the front group, and RGF indicates the composite focal length of the rear group. TTL indicates the total optical length on the optical axis O from the object-side lens surface S1 of the first lens L1 to the imaging surface S17 of the image sensor 12 in the imaging lens system 11. L2-L3 indicates the spatial interval (distance) on the optical axis O between the lens surface S4 of the second lens L2 and the lens surface S6 of the third lens L3.

[0037] In this case, the imaging lens system 11 has a bright F-number of 1.6 and a wide-angle lens with a half angle of view of 48.5°. The wavelength (reference wavelength) of the light ray used to calculate paraxial quantities including the focal length and F-number is the e-line (546 nm).

[0038] Fig. 2(a) is a diagram of spherical aberration of the imaging lens system 11 of Example 1. In Fig. 2(a), the vertical axis represents pupil coordinates normalized to an entrance pupil diameter of 1, and the horizontal axis represents distance along the optical axis O. Fig. 2(a) shows spherical aberration for each wavelength, with the F-line (486 nm) represented by a dashed line, the d-line (587 nm) by a solid line, and the C-line (656 nm) by a dashed-dotted line.

[0039] Fig. 2(b) is a diagram of astigmatism / field curvature of the imaging lens system 11 of Example 1. In Fig. 2(b), the vertical axis represents the angle of view, and the horizontal axis represents the distance along the optical axis O. In Fig. 2(b), the imaging plane for the sagittal ray bundle is represented by a solid line, and the imaging plane for the tangential ray bundle is represented by a dashed line. In this case, the wavelength of the light ray to be evaluated is the e-line (546 nm).

[0040] [Example 2] 3 is a cross-sectional view showing the configuration of an imaging lens system 11 of a camera module 10 of Example 2. In the imaging lens system 11 of Example 2 shown in FIG. 3, the second lens L2 has a lens surface S3 having a convex shape on the object side and a lens surface S4 having a concave shape on the image side. The second lens L2 is a meniscus-shaped plastic lens with positive refractive power. The configuration of the imaging lens system 11 of Example 2 other than the second lens L2 is the same as that of Example 1, and therefore a description thereof will be omitted.

[0041] Table 4 shows lens data for each lens surface of the imaging lens system 11 of Example 2. The lens data in Table 4 shows data for the same items as in Table 1.

[0042] [Table 4]

[0043] Table 5 shows aspherical coefficients and the like for defining the aspherical shape of the aspherical lens surface in the imaging lens system 11 of Example 2. Table 5 shows values ​​for the same items as Table 2.

[0044] [Table 5]

[0045] Table 6 shows the characteristic values ​​of the imaging lens system 11 of Example 2 shown in Tables 4, 5, etc., as values ​​for the same items as those in Table 3, which shows the characteristic values ​​of Example 1. Note that the F-number of the imaging lens system 11 in this case is 1.6, which is bright, and the half angle of view is 47.9°, making it a wide-angle lens. The wavelength (reference wavelength) of the light ray used to calculate paraxial quantities including the focal length and F-number is the e-line (546 nm).

[0046] [Table 6]

[0047] Fig. 4(a) is a diagram of spherical aberration of the imaging lens system 11 of Example 2. Fig. 4(b) is a diagram of astigmatism / field curvature of the imaging lens system 11 of Example 2. Figs. 4(a) and 4(b) show graphs for the same items as Figs. 2(a) and 2(b), and therefore the explanations for each aberration diagram are the same and will be omitted.

[0048] [Example 3] 5 is a cross-sectional view showing the configuration of the imaging lens system 11 of the camera module 10 of Example 3. The configuration of the imaging lens system 11 of Example 3 is the same as that of Example 1, and therefore a description thereof will be omitted.

[0049] Table 7 shows the lens data of each lens surface of the imaging lens system 11 of Example 3. The lens data in Table 7 shows data for the same items as in Table 1.

[0050] [Table 7]

[0051] Table 8 shows aspherical coefficients and the like for defining the aspherical shape of the aspherical lens surface in the imaging lens system 11 of Example 3. Table 8 shows values ​​for the same items as Table 2.

[0052] [Table 8]

[0053] Table 9 shows the characteristic values ​​of the imaging lens system 11 of Example 3 shown in Tables 7, 8, etc., as values ​​for the same items as those in Table 3, which shows the characteristic values ​​of Example 1. Note that the F-number of the imaging lens system 11 in this case is 1.6, which is bright, and the half angle of view is 48.5°, making it a wide-angle lens. The wavelength (reference wavelength) of the light ray for paraxial quantities including the focal length and F-number is the e-line (546 nm).

[0054] [Table 9]

[0055] Fig. 6(a) is a diagram of spherical aberration of the imaging lens system 11 of Example 3. Fig. 6(b) is a diagram of astigmatism / field curvature of the imaging lens system 11 of Example 3. Figs. 6(a) and 6(b) show graphs for the same items as Figs. 2(a) and 2(b), and therefore the explanations for each aberration diagram are the same and will be omitted.

[0056] [Example 4] 7 is a cross-sectional view showing the configuration of the imaging lens system 11 of the camera module 10 of Example 4. The configuration of the imaging lens system 11 of Example 4 is the same as that of Example 1, and therefore a description thereof will be omitted.

[0057] Table 10 shows the lens data for each lens surface of the imaging lens system 11 of Example 4. The lens data in Table 10 shows data for the same items as in Table 1.

[0058] [Table 10]

[0059] Table 11 shows aspherical coefficients and the like for defining the aspherical shape of the aspherical lens surface in the imaging lens system 11 of Example 4. Table 11 shows values ​​for the same items as Table 2.

[0060] [Table 11]

[0061] Table 12 shows the characteristic values ​​of the imaging lens system 11 of Example 4 shown in Tables 10, 11, etc., as values ​​for the same items as those in Table 3, which shows the characteristic values ​​of Example 1. Note that the F-number of the imaging lens system 11 in this case is 1.6, which is bright, and the half angle of view is 48.5°, making it a wide-angle lens. The wavelength (reference wavelength) of the light ray for paraxial quantities including the focal length and F-number is the e-line (546 nm).

[0062] [Table 12]

[0063] Fig. 8(a) is a diagram of spherical aberration of the imaging lens system 11 of Example 4. Fig. 8(b) is a diagram of astigmatism / field curvature of the imaging lens system 11 of Example 4. Figs. 8(a) and 8(b) show graphs for the same items as Figs. 2(a) and 2(b), and therefore the explanations for each aberration diagram are the same and will be omitted.

[0064] [Conditional Expression Summary] Table 13 shows a summary of the characteristic values ​​of the imaging lens system 11 in Examples 1 to 4. Table 14 shows related values ​​calculated from the values ​​in Table 13.

[0065] [Table 13]

[0066] [Table 14]

[0067] In this way, the imaging lens system 11 of this embodiment satisfies the following conditional expression (1) when the focal length of the first lens is f1 and the focal length of the second lens is f2. |f2 / f1|>10 (1)

[0068] Furthermore, the imaging lens system 11 satisfies 45>|f2 / f1|. It is even more preferable that the imaging lens system 11 satisfies 25>|f2 / f1|>15.

[0069] By satisfying this conditional expression (1), the imaging lens system 11 can correct spherical aberration and astigmatism without giving the second lens a strong power (refractive power), and can obtain good imaging performance.

[0070] The imaging lens system 11 of this embodiment uses a glass lens for the first lens and a plastic lens for the second lens. The imaging lens system 11 suppresses aberration fluctuations with temperature changes over the entire angle of view corresponding to a wide field of view, and provides good imaging performance.

[0071] The imaging lens system 11 of this embodiment satisfies the following conditional expression (2), where the composite focal length of the front group is FGF and the composite focal length of the rear group is RGF. 1.0<|FGF / RGF|<1.5 (2)

[0072] It is more preferable that the imaging lens system 11 satisfies 1.0<|FGF / RGF|<1.3.

[0073] By satisfying conditional expression (2), the imaging lens system 11 can maintain good, bright imaging performance with high resolution over the entire angle of view corresponding to a wide field of view, and can ensure a small size and appropriate back focus. That is, if |FGF / RGF| is greater than 1.5 or 1.3, the power of the front group of the imaging lens system 11 (optical system) becomes weak and the system becomes large. If |FGF / RGF| is less than 1.0 or 1.1, the power of the front group becomes too strong, making it difficult to correct aberrations such as field curvature, and good imaging performance cannot be obtained.

[0074] The imaging lens system 11 of this embodiment satisfies the following conditional formula (3), where the distance on the optical axis O between the lens surface S4 of the second lens L2 and the lens surface S6 of the third lens L3 is a distance L2-L3, and the distance on the optical axis O from the object side surface of the first lens to the imaging surface of the imaging element is a total optical length TTL. (L2-L3) / TTL<0.15 (3)

[0075] Furthermore, the imaging lens system 11 (optical system) satisfies 0.09<(L2-L3) / TTL. It is more preferable that the imaging lens system 11 (optical system) satisfies 0.11<(L2-L3) / TTL<0.12.

[0076] By satisfying conditional expression (3), the imaging lens system 11 can maintain good, bright imaging performance with high resolution over the entire angle of view corresponding to a wide field of view, can be made compact without the lens diameter of the rear group being larger than that of the front group, and can ensure a long back focus.

[0077] This makes it easier to provide an adjustment mechanism that compensates for the effects of focus deviation and image plane tilt caused by manufacturing errors such as lens decentering.

[0078] The imaging lens system 11 of this embodiment satisfies the following conditional expression (4), where the focal length of the second lens is f2 and the focal length of the entire lens system is f. 10<|f2 / f| (4)

[0079] Furthermore, the imaging lens system 11 (optical system) satisfies |f2 / f|<70. It is even more preferable that the imaging lens system 11 (optical system) satisfies 20<|f2 / f|<42.

[0080] By satisfying conditional expression (4), the imaging lens system 11 can maintain good, bright imaging performance with high resolution over the entire angle of view corresponding to a wide field of view. Furthermore, the imaging lens system 11 can reduce the contribution ratio of the power of the second lens L2 to the power of the entire system, thereby reducing focus shift and aberration fluctuations due to temperature changes. On the other hand, if |f2 / f| is less than 10 or 20, the imaging lens system 11 will experience large power fluctuations due to temperature changes, making it difficult to maintain stable imaging performance.

[0081] Furthermore, imaging lens system 11 of this embodiment satisfies the following conditional expression (5), where f1 is the focal length of the first lens and f is the focal length of the entire lens system. d1.0<|f1 / f|<2.0 (5)

[0082] It is more preferable that the imaging lens system 11 (optical system) satisfies 1.4<|f1 / f|<1.6.

[0083] By satisfying conditional expression (5), it is possible to achieve compactness while maintaining good, bright imaging performance with high resolution over the entire angle of view corresponding to a wide field of view. That is, in the imaging lens system 11 (optical system), if |f1 / f| is greater than 2.0 or 1.6, the power of the first lens L1 becomes weak, and the optical system becomes large. Also, in the imaging lens system 11, if |f1 / f| is less than 1.0 or 1.4, the power of the first lens L1 becomes too strong, making it difficult to correct aberrations such as chromatic aberration of magnification, and maintaining good imaging performance becomes difficult.

[0084] [Variations] The present invention is not limited to the above-described embodiment, and includes various other modifications. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the described configurations.

[0085] It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment, and it is also possible to add, delete, or replace part of the configuration of each embodiment with the configuration of another embodiment. [Embodiment 2] FIG. 9 is a diagram showing the configuration of an imaging device 50 equipped with imaging lens system 11 according to the first embodiment. As shown, an imaging device 50 according to the embodiment includes a camera module 10 that houses an imaging lens system 11, an imaging element 12, etc. in a housing (not shown), a control unit 52, and a storage unit .

[0086] The control unit 52 controls the camera module 10 and processes the electrical signals output from the image sensor 12 of the camera module 10. The control unit 52 may be configured with, for example, a processor unit (PU), RAM, ROM, etc. The control unit 52 may also include one or more processors.

[0087] The processor may include a general-purpose processor that loads a specific program to execute a specific function, and a dedicated processor specialized for a specific process. The dedicated processor may include an application-specific integrated circuit (IC). An application-specific IC is also called an application-specific integrated circuit (ASIC). The processor may include a programmable logic device. A programmable logic device is also called a programmable logic device (PLD). A PLD may include a field-programmable gate array (FPGA). The control unit 52 may be either a system-on-a-chip (SoC) or a system in a package (SiP) in which one or more processors work together.

[0088] The storage unit 54 stores various information or parameters related to the operation of the imaging device 50. The storage unit 54 may be configured with, for example, a semiconductor memory or the like. The storage unit 54 may function as a work memory for the control unit 52. The storage unit 54 may store captured images. The storage unit 54 may store various information or parameters, etc., used by the control unit 52 to perform detection processing and control based on the captured images. The storage unit 54 may be included in the control unit 52.

[0089] As described above, the camera module 10 captures an image of a subject (object) formed via the imaging lens system 11 with 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.

[0090] The imaging element 12 may be configured, for example, as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device). The imaging element 12, which is disposed at the focal position of the imaging lens system 11, has an imaging surface on which a plurality of pixels are arranged. Each pixel outputs a signal specified by a current or voltage according to the amount of incident light. The signal output by each pixel is also referred to as imaging data.

[0091] The imaging data may be read by the camera module 10 for all pixels and imported into the control unit 52 as a captured image. A captured image read out from all pixels is also referred to as a maximum captured image. The imaging data may be read by the camera module 10 for some pixels and imported as a captured image. In other words, the imaging data may be read out from pixels in a predetermined capture range. The imaging data read out from pixels in the predetermined capture range may be imported as a captured image. The predetermined capture range may be set by the control unit 52. The camera module 10 may acquire the predetermined capture range from the control unit 52. The imaging element 12 may capture an image of a subject image formed via the imaging lens system 11 within a predetermined capture range. The imaging device 50 (imaging camera) may also be an imaging system in which the camera module 10 is a separate entity and connected via a cable or the like. [Embodiment 3] FIG. 10 is a schematic diagram of a vehicle 40 equipped with an in-vehicle system including an imaging device 50 including an imaging lens system according to embodiment 1 or embodiment 2 and an imaging element that converts light collected through the imaging lens system into an electrical signal.

[0092] 10, a vehicle 40, which is an automobile that runs (moves) day and night, is equipped with tires, a steering wheel, etc. for running. The imaging device 50 can be mounted on the vehicle 40, which is a moving body. The vehicle 40 is also equipped with an information processing device 42, a display device 43, etc.

[0093] FIG. 10 shows an example of an arrangement of a plurality of mounting positions of the imaging device 50 in the vehicle 40. For example, a first imaging device 50a, which is one of the imaging devices 50, may be disposed on or near the front bumper as a camera for monitoring the front of the vehicle 40 while the vehicle 40 is traveling. A second imaging device 50b, which is one of the imaging devices 50 for monitoring the front, may be disposed near an inner rearview mirror inside the vehicle 40. A third imaging device 50c may be disposed on the dashboard or in the instrument panel as a camera for monitoring the driving status of the driver. A fourth imaging device 50d may be installed at the rear of the vehicle 40 to monitor the rear of the vehicle 40.

[0094] The first imaging device 50a and the second imaging device 50b can be called front cameras. The third imaging device 50c can be called an in-camera. The fourth imaging device 50d can be called a rear camera. The imaging device 50 is not limited to these, and includes imaging devices installed in various positions, such as a left side camera that captures images of the left rear side and a right side camera that captures images of the right rear side.

[0095] In this way, the imaging lens system 11 in the imaging device 50 is lightweight and has a stable weight balance, so the imaging device 50 can be easily installed in various positions on the vehicle 40.

[0096] FIG. 11 is a configuration diagram of a vehicle 40 equipped with an in-vehicle system 41 having an imaging device 50 including an imaging lens system 11 according to embodiment 1 or embodiment 2 and an imaging element 12 that converts light collected through the imaging lens system 11 into an electrical signal.

[0097] 11 , an imaging device 50 mounted on a vehicle 40 serving as an automobile can also be called an on-board camera, and can be installed in various locations on the vehicle 40. An on-board system 41 equipped with an imaging device 50 mounted on a vehicle 40 serving as an automobile is also a mobile body mounted system equipped with an imaging device 50 mounted on a mobile body. In other words, the mobile body is not limited to a vehicle 40 serving as an automobile, but also includes, for example, a moving bicycle, a motorbike, a wheelchair, a train, a drone, a helicopter, an airplane, a ship, and the like.

[0098] 11 , an image signal of an image captured by the imaging device 50 is output to an information processing device 42, a display device 43, etc. of the vehicle 40 via a cable, a bus, etc. Furthermore, the image signal of the captured image may be output to an information processing device, a display device, etc. of a control center via wireless communication, a network, etc. The in-vehicle system 41 includes at least the information processing device 42 and the imaging device 50. The in-vehicle system 41 may also include the information processing device 42, the imaging device 50, the display device 43, etc.

[0099] The information processing device 42 of the vehicle 40 acquires captured images output from the camera module 10 of the imaging device 50 and processes the image signals of the captured images. The information processing device 42 may synthesize and process captured images acquired by a first imaging device 50a and a second imaging device 50b, which are imaging devices 50 as shown in Fig. 10. The information processing device 42 may be composed of, for example, a processor unit (PU), RAM, ROM, etc.

[0100] The information processing device 42 recognizes various objects in the captured image, such as people (including the driver of the vehicle 40 captured by the in-camera), other vehicles, other moving objects, animals, roads, road signs, etc., and generates recognition information such as the image, type, position, and movement speed of the object.

[0101] The captured image may be an image in the direction of movement of the vehicle 40, or it may be one or more images that meet a predetermined condition, for example, one image when the vehicle 40 is traveling at or above a predetermined speed, and multiple images when the vehicle 40 is traveling at or below that speed.

[0102] The information processing device 42 includes a device that assists the driver in driving, such as, but not limited to, a navigation device, a collision damage mitigation braking device, a vehicle-to-vehicle distance control device, and a lane departure warning device.

[0103] The display device 43 displays images and the like as recognition information processed and output by the information processing device 42, but can also receive image signals such as captured images directly from the imaging device 50 and display the images.

[0104] Furthermore, the display device 43 may be, but is not limited to, a liquid crystal display (LCD), an organic electroluminescence (EL) display, or an inorganic EL display. The display device 43 can also display to a passenger such as the driver an image signal output from an image capture device 50 that captures an image in a position that is difficult for the driver to view, such as a rear camera, for example, the fourth image capture device 50d.

[0105] It should be noted that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention. For example, the use of the imaging lens system 11 of the present invention is not limited to vehicle-mounted cameras, and it can also be used for other purposes, such as fixedly installed surveillance cameras and cameras mounted on small electronic devices such as portable mobile phones.

[0106] Furthermore, the present invention includes various embodiments other than those described above. For example, the above-described embodiment examples have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the described configurations.

[0107] Furthermore, in the present invention, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment.Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0108] 1: Aperture (STOP), 10: camera module, 11: imaging lens system, 12: Image sensor (IMG), 13: Cover glass (CG), 14: IR cut filter (IRCF), 40: Vehicle, 41: In-vehicle systems, 42: Information processing device, 43:Display device, 50, 50a, 50b, 50c, 50d: imaging device (imaging camera, in-vehicle camera), 52: control unit, 54: Memory section, L1: First lens, L2: Second lens, L3: third lens, L4: fourth lens, L5: fifth lens, L6: sixth lens, S1 to S4, S6 to S12: lens surfaces, S5: Aperture plane, S13, S14: IRCF surface, S15, S16: CG surface, S17: Imaging surface.

Claims

1. In an imaging lens system that is composed of, in order from the object side to the image side, a front group and a rear group, the front group is composed of a first lens element having a concave surface facing the image side and having negative refractive power, and a second lens element, the rear group is composed of a third lens element having positive refractive power, a fourth lens element having positive refractive power, a fifth lens element having a concave surface facing the image side and having negative refractive power, and a sixth lens element having positive refractive power, the first lens and the third lens are glass lenses, and the second lens is a plastic lens; the fourth lens forms a cemented lens cemented to the fifth lens, An imaging lens system characterized in that, when the focal length of the first lens is f1 and the focal length of the second lens is f2, the following conditional expression (1) is satisfied: |f2 / f1|>10 (1)

2. 2. The imaging lens system according to claim 1, An imaging lens system characterized in that, when a composite focal length of the front group is FGF and a composite focal length of the rear group is RGF, the following conditional expression (2) is satisfied: 1.0<|FGF / RGF|<1.5 (2)

3. 2. The imaging lens system according to claim 1, an imaging lens system, characterized in that the following conditional expression (3) is satisfied when a distance on the optical axis between the second lens and the third lens is L2-L3 and a distance on the optical axis from an object-side surface of the first lens to an imaging surface of an imaging element is TTL: (L2-L3) / TTL<0.15 (3)

4. 2. The imaging lens system according to claim 1, An imaging lens system characterized in that, when the focal length of the entire lens system is f, the following conditional expression (4) is satisfied: 10<|f2 / f| (4)

5. 2. The imaging lens system according to claim 1, An imaging lens system characterized in that, when the focal length of the entire lens system is f, the following conditional expression (5) is satisfied: 1.0<|f1 / f|<2.0 (5)

6. 6. A camera module comprising: the imaging lens system according to claim 1; and an imaging element that converts light collected through the imaging lens system into an electrical signal.

7. 7. An imaging device comprising: a camera module according to claim 6; a control unit that controls said camera module; and a storage unit that stores information for said control unit to perform control.

8. 7. An in-vehicle system comprising: a camera module according to claim 6; and an information processing device that recognizes an object in a captured image output from the camera module and generates recognition information.

9. an information processing device that recognizes an object in a captured image output from the camera module and generates recognition information; and a display device that displays information, The information processing device is characterized in that the recognition information of the object is displayed on the display device.

Images