Imaging lens system, camera module, in-vehicle system, and mobile body

Abstract

Provided are a high-resolution imaging lens system, a camera module, an in-vehicle system, and a mobile body. In an imaging lens system (11), a first lens (L1) having negative power and a convex surface facing the object side on the object-side surface thereof, a second lens (L2) having negative power and a concave surface facing the object side on the object-side surface thereof, a third lens (L3) having positive power and a convex surface facing the object side on the object-side surface thereof, and a fourth lens (L4) are disposed in order from the object side to the image side. An aperture STOP is disposed between the second lens (L2) and the fourth lens (L4). The object-side surface of the first lens (L1) has an aspherical shape. When the on-axis radius of curvature of the object-side surface of the first lens (L1) is defined as R0, the maximum value of the radius of curvature is defined as Rmax, the radius at which the radius of curvature becomes the maximum value Rmax is defined as hRmax, and the effective diameter is defined as hmax, the imaging lens system (11) satisfies the following conditional formulas (1) and (2).　(1): 1.4<Rmax / R0<1.7 (2): 0.6<hRmax / hmax<0.95

Description

Imaging lens systems, camera modules, in-vehicle systems, mobile objects

[0001] The present invention relates to an imaging lens system, a camera module, an in-vehicle system, and a moving body.

[0002] In recent years, vehicle-mounted cameras have been required to have sensing functions for detecting people and objects, and image sensors have become larger and with higher resolution. Accordingly, imaging lens systems mounted on vehicle-mounted cameras and the like are also required to have higher resolution. Patent Document 1 describes a lens system consisting of six lenses mounted on a vehicle-mounted camera and the like.

[0003] Special Publication No. 2021-516793

[0004] However, in the imaging lens system described in Patent Document 1, the first lens is an aspherical lens and has an inflection point on the object-side surface. Therefore, there is a problem in that coma aberration occurring in the first lens is likely to increase due to decentering of the first lens during assembly of the imaging lens system. Furthermore, there is a problem in that coma aberration occurring in the first lens is likely to increase due to decentering of the third lens during assembly of the imaging lens system because the third lens has a high power. Therefore, there is a possibility that Patent Document 1 will not be able to realize an imaging lens system with sufficiently high resolution.

[0005] The present invention has been made in view of the above problems, and has an object to provide a high-resolution imaging lens system, a camera module, an in-vehicle system, and a mobile body.

[0006] In one embodiment, the imaging lens system includes, in order from the object side to the image side, a first lens having a convex object-side surface facing the object side and negative power, a second lens having a concave object-side surface facing the object side and negative power, a third lens having a convex object-side surface facing the object side and positive power, and a fourth lens, and an aperture is disposed between the second lens, the third lens, and the fourth lens, and the object-side surface of the first lens has an aspherical shape, and the axial radius of curvature of the object-side surface of the first lens is R ０ , the maximum value of the radius of curvature of the object side surface of the first lens is R ｍａｘ, the radius of curvature of the object side surface of the first lens is the maximum value R ｍａｘ The radius at which Ｒｍａｘ , the effective diameter of the object side surface of the first lens is h ｍａｘ When R is defined as follows, the imaging lens system satisfies the following conditional expressions (1) and (2): 1.4<R ｍａｘ / R ０ <1.7...(1) 0.6<h Ｒｍａｘ / h ｍａｘ <0.95 ... (2)

[0007] According to the present invention, it is possible to provide a high-resolution imaging lens system, a camera module, an in-vehicle system, and a mobile object.

[0008] FIG. 1 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 1. FIG. 2 is a diagram showing spherical aberration in the imaging lens system according to Example 1. FIG. 3 is a diagram showing curvature of field in the imaging lens system according to Example 1. FIG. 4 is a diagram showing distortion in the imaging lens system according to Example 1. FIG. 5 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 2. FIG. 6 is a diagram showing spherical aberration in the imaging lens system according to Example 2. FIG. 7 is a diagram showing curvature of field in the imaging lens system according to Example 2. FIG. 8 is a diagram showing distortion in the imaging lens system according to Example 2. FIG. 9 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 3. FIG. 10 is a diagram showing spherical aberration in the imaging lens system according to Example 3. FIG. 11 is a diagram showing curvature of field in the imaging lens system according to Example 3. FIG. 12 is a diagram showing distortion in the imaging lens system according to Example 3. FIG. 13 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 4. FIG. 14 is a diagram showing spherical aberration in the imaging lens system according to Example 4. FIG. 15 is a diagram showing curvature of field in the imaging lens system according to Example 4. FIG. 16 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 5. 11 is a diagram illustrating spherical aberration in the imaging lens system of Example 5. FIG. 12 is a diagram illustrating field curvature in the imaging lens system of Example 5. FIG. 13 is a diagram illustrating distortion aberration in the imaging lens system of Example 5. FIG. 14 is a schematic diagram of a vehicle on which an in-vehicle system including a camera module according to an embodiment of the present invention is mounted. FIG. 15 is a block diagram illustrating the configuration of an imaging device constituting the in-vehicle system of FIG.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present embodiments can realize highly reliable systems, particularly in sensing systems, and contribute to the development of resilient infrastructure. The target of the Sustainable Development Goals (SDGs) advocated by the United Nations is "9. Build resilient infrastructure, promote industry, innovation and infrastructure," which states, "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." (Embodiment 1: Imaging Lens System) In an imaging lens system according to embodiment 1, a first lens having a negative power and a convex object-side surface facing the object side, a second lens having a negative power and a concave object-side surface facing the object side, a third lens having a positive power and a convex object-side surface facing the object side, and a fourth lens are arranged in this order from the object side to the image side, and an aperture is arranged between the second lens, the third lens, and the fourth lens, the object-side surface of the first lens has an aspherical shape, and the axial radius of curvature of the object-side surface of the first lens is R ０ , the maximum value of the radius of curvature of the object side surface of the first lens is R ｍａｘ , the radius of curvature of the object side surface of the first lens is the maximum value R ｍａｘ The radius at which Ｒｍａｘ , the effective diameter (also called "effective radius") of the object side surface of the first lens is h ｍａｘ When R is defined as follows, the imaging lens system satisfies the following conditional expressions (1) and (2): 1.4<R ｍａｘ / R ０ <1.7...(1) 0.6<h Ｒｍａｘ / h ｍａｘ <0.95 (2) Here, the position (coordinate) of interest in the radial direction of the lens is h ｉ , the position h ｉ The position h closer to the center of the lens than ｉ The position (coordinate) closest to h １ , the position h ｉ The position h on the peripheral side of the lens ｉ The position (coordinate) closest to h ２ , the position h １The amount of sag at Z １ , the position h ２ The amount of sag at Z ２ When the position h is defined as ｉ The radius of curvature R ｉ Is Z １ -Z ２ = (R ｉ ２ -h １ ２ ) １／２ - (R ｉ ２ -h ２ ２ ) １／２ Satisfy.

[0010] This makes it possible to provide a high-resolution imaging lens system. Specifically, by making the imaging lens system satisfy the above conditional expressions (1) and (2), it is possible to suppress an increase in coma aberration due to decentering of the first lens, and it is also possible to suppress an increase in coma aberration due to decentering of the third lens. This makes it possible to realize a high-resolution imaging lens system. More specifically, R ｍａｘ / R ０ If the value of R is 1.4 or less, the curvature of the peripheral part of the object side surface of the first lens becomes too sharp, the coma aberration occurring in the first lens becomes too large, and even a slight decentering of the third lens becomes unacceptable. ｍａｘ / R ０ If the value of h is 1.7 or more, the curvature of the peripheral part of the object side surface of the first lens becomes too gentle, and coma aberration is likely to increase due to decentering of the first lens, so even a slight decentering of the first lens becomes unacceptable. Ｒｍａｘ / h ｍａｘ If the value of h is 0.6 or less, the portion of the object side surface of the first lens where the curvature is the gentlest is too close to the center of the lens, and coma aberration is likely to increase in the peripheral portion of the image plane due to slight decentering of the first lens or the third lens. Ｒｍａｘ / h ｍａｘIf the value of R is 0.95 or more, the portion of the object-side surface of the first lens where the curvature is the gentlest is too close to the edge of the lens, and in the range from the center to the periphery of the image plane, a slight decentering of the first lens or a slight decentering of the third lens tends to increase coma aberration. ｍａｘ / R ０ The lower limit of R is more preferably 1.45, and even more preferably 1.50. ｍａｘ / R ０ The upper limit of h is more preferably 1.65, and even more preferably 1.60. Ｒｍａｘ / h ｍａｘ The lower limit of h is more preferably 0.65, 0.70, and even more preferably 0.75. Ｒｍａｘ / h ｍａｘ The upper limit value of is more preferably 0.90, 0.85, and even more preferably 0.80. Therefore, if the imaging lens system satisfies the above conditional expressions (1) and (2), it is possible to provide an imaging lens system with high resolution.

[0011] Furthermore, it is preferable that the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in this order from the object side to the image side, the fourth lens having positive power and the fifth lens having negative power, and where the Abbe number of the fourth lens for the d-line is defined as vd4 and the Abbe number of the fifth lens for the d-line is defined as vd5, the following conditional expressions (3) and (4) are satisfied, and the image-side surface of the fourth lens and the object-side surface of the fifth lens are cemented together: vd4>50 (3) vd5<30 (4) By cementing the fourth lens having positive power that satisfies the above conditional expression (3) with the fifth lens having negative power that satisfies the above conditional expression (4), it is possible to achieve a balance in dispersion between the fourth lens and the fifth lens, and to correct axial chromatic aberration. Furthermore, by cementing the image-side surface of the fourth lens with the object-side surface of the fifth lens, it is possible to suppress light loss due to reflection on these surfaces. The lower limit of vd4 is more preferably 51, 52, or 53, and even more preferably 54. The upper limit of vd5 is more preferably 29, 28, 27, or 26, and even more preferably 25.

[0012] Furthermore, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in this order from the object side to the image side, and it is preferable that the fourth lens has positive power, the fifth lens has negative power, and the sixth lens has positive power. By having the sixth lens have positive power, the sixth lens can share the positive power of the entire imaging lens system, and the positive power shared by the third lens can be reduced accordingly. Therefore, it is possible to suppress an increase in coma aberration of the first lens due to decentering of the third lens.

[0013] It is also preferable that the object-side and image-side surfaces of the sixth lens have aspherical shapes, which makes it possible to correct various aberrations and realize an imaging lens system with good imaging performance.

[0014] Furthermore, it is preferable that, of the lenses arranged closer to the image than the aperture stop, the image-side surface of the lens arranged closest to the image side has a concave surface facing the image side. This allows light rays to be emitted off-axis from the image-side surface of the lens arranged closest to the image side among the lenses arranged closer to the image than the aperture stop, and makes it possible to make the effective image circle diameter sufficiently large compared to the overall optical length of the imaging lens system. Note that the overall optical length is the distance along the optical axis from the object-side surface of the first lens in the imaging lens system to the image plane. Furthermore, the effective image circle diameter is the diameter of a circular image (effective image circle) formed by the imaging lens system that can ensure optical performance.

[0015] Furthermore, of the lenses arranged closer to the image side than the aperture stop, it is preferable that the object-side and image-side surfaces of the lens arranged closest to the image side have aspherical shapes, which makes it possible to correct various aberrations and realize an imaging lens system with good imaging performance.

[0016] (Embodiment 2: Camera Module) A camera module according to embodiment 2 includes the above-described imaging lens system and an imaging element that is disposed at the focal position of the imaging lens system and converts light condensed through the imaging lens system into an electrical signal, thereby providing a high-resolution camera module.

[0017] 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. (Example 1) Fig. 1 is a cross-sectional view showing the configuration of a 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 housed in a housing (not shown).

[0018] The imaging element 12 is an element that converts received light into an electrical signal, and is, for example, a CCD image sensor or a CMOS image sensor. The imaging element 12 is disposed at the image forming position (focal position) of the imaging lens system 11.

[0019] The imaging lens system 11 according to Example 1 includes, in order from the object side to the image side, a front group Gf including a first lens L1, a second lens L2, and a third lens L3, an aperture stop (STOP), and a rear group Gr including a fourth lens L4, a fifth lens L5, and a sixth lens L6. The image plane of the imaging lens system 11 is indicated by IMG. Note that an optical filter (such as an infrared transmission filter, a visible / infrared bandpass filter, or an infrared cut filter) is disposed between the imaging lens system 11 and the image sensor 12 as needed. In this specification, an example in which an infrared cut filter (IRCF) is disposed between the imaging lens system 11 and the image sensor 12 will be described.

[0020] The first lens L1 is a meniscus lens having negative power. The object-side surface S1 of the first lens L1 has an aspheric shape with a convex surface facing the object side. The image-side surface S2 of the first lens L1 has an aspheric shape with a concave surface facing the image side.

[0021] The second lens L2 is a meniscus lens having negative power. The object-side surface S3 of the second lens L2 has a spherical shape with a concave surface facing the object side. The image-side surface S4 of the second lens L2 has a spherical shape with a convex surface facing the image side.

[0022] The third lens L3 has positive power. The object-side surface S5 of the third lens L3 has a spherical shape with a convex surface facing the object side. The image-side surface S6 of the third lens L3 also has a spherical shape with a convex surface facing the image side.

[0023] The aperture stop STOP is an aperture that determines the F-number (F-number, Fno) of the lens system. The aperture stop STOP is disposed between the third lens L3 and the fourth lens L4.

[0024] The fourth lens L4 has positive power. The object-side surface S8 of the fourth lens L4 has a spherical shape with a convex surface facing the object side. The image-side surface S9 of the fourth lens L4 also has a spherical shape with a convex surface facing the image side.

[0025] The fifth lens L5 has negative power, an object-side surface S10 of the fifth lens L5 has a spherical shape with a concave surface facing the object side, and an image-side surface S11 of the fifth lens L5 has a spherical shape with a concave surface facing the image side.

[0026] The fourth lens L4 and the fifth lens L5 form a cemented lens. That is, the image-side surface S9 of the fourth lens L4 and the object-side surface S10 of the fifth lens L5 are in contact with each other. The fourth lens L4 and the fifth lens L5 are cemented together with an adhesive layer having an axial thickness of 0.005 mm.

[0027] The sixth lens L6 has positive power. The object-side surface S12 of the sixth lens L6 has an aspheric shape with a convex surface facing the object side. The image-side surface S13 of the sixth lens L6 has an aspheric shape with a concave surface facing the image side.

[0028] The infrared cut filter (IRCF) is a filter for cutting 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 disposed on the image side of the lens disposed closest to the image, i.e., on the image side of the sixth lens L6 in Example 1. Furthermore, a sensor cover glass may be disposed between the infrared cut filter and the imaging element 12 to prevent dust from adhering to the imaging element 12.

[0029] Table 1 shows lens data for each lens surface in the imaging lens system 11 of Example 1. Table 1 presents the lens data, including the on-axis radius of curvature (mm), the surface spacing (mm) on the optical axis OA, the refractive index nd for the d-line, and the Abbe number vd for the d-line. In Table 1, surfaces marked with an asterisk (*) are aspherical. In addition, the imaging lens system 11 of Example 1 has an F-number of 1.6 and a total angle of view of 82°.

[0030]

[0031] The aspherical shape adopted for the lens surface is as follows: Z is the sag amount, c is the inverse of the radius of curvature, k is the conic coefficient, r is the height from the optical axis OA, and the aspherical coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th orders are respectively α ４ , α ６ , α ８ , α １０ , α １２ , α １４ , α １６ When this is the case, it is expressed by the following equation:

[0032] Table 2 shows aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 11 of Example 1. In Table 2, for example, "-1.00980E-03" corresponds to "-1.00980×10 －３ The same applies to the numerical expressions in the following tables.

[0033]

[0034] Next, aberrations will be described with reference to the drawings. Figures 2A to 2C show spherical aberration diagrams (longitudinal aberration diagrams), field curvature diagrams, and distortion diagrams for the imaging lens system 11 of Example 1. In the longitudinal aberration diagram of Figure 2A, the horizontal axis indicates the position where a light ray intersects with the optical axis OA, and the vertical axis indicates the height at which the light ray passes through the entrance pupil. Figure 2A also shows simulation results for light rays with wavelengths of 455 nm, 522 nm, 546 nm, 558 nm, 614 nm, and 661 nm. In the field curvature diagram of Figure 2B, the horizontal axis indicates the distance in the direction of the optical axis OA, and the vertical axis indicates the image height (angle of view). In the field curvature diagram of Figure 2B, Sag indicates the image formation position for a sagittal ray bundle, and Tan indicates the image formation position for a tangential ray bundle. 2B shows simulation results for light rays with wavelengths of 455 nm, 522 nm, 546 nm, 558 nm, 614 nm, and 661 nm. In the distortion diagram of FIG. 2C, the horizontal axis represents image distortion (%), and the vertical axis represents image height (angle of view). FIG. 2C also shows simulation results for light rays with a wavelength of 550 nm.

[0035] 3 is a cross-sectional view showing a camera module 10 according to Example 2. The configuration of the imaging lens system 11 according to Example 2 is the same as that of Example 1, and therefore a description thereof will be omitted. Below, characteristic data of the imaging lens system 11 according to Example 2 will be described.

[0036] Table 3 shows lens data for each lens surface of the imaging lens system 11 according to Example 2. The items shown in Table 3 are the same as those in Table 1, and therefore their explanation will be omitted. Furthermore, the imaging lens system 11 according to Example 2 has an F-number of 1.6 and a total angle of view of 82°.

[0037]

[0038] Table 4 shows aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 11 of Example 2. In Table 4, the aspherical shape adopted for the lens surface is expressed by the same formula as in Example 1.

[0039]

[0040] 4A to 4C show diagrams of spherical aberration (longitudinal aberration), field curvature, and distortion in the imaging lens system 11 of Example 2. The explanation of each aberration diagram shown in Figures 4A to 4C is the same as that of Figures 2A to 2C, and therefore will not be repeated.

[0041] 5 is a cross-sectional view showing a camera module 10 according to Example 3. The configuration of the imaging lens system 11 according to Example 3 is the same as that of Example 1, and therefore a description thereof will be omitted. Below, characteristic data of the imaging lens system 11 according to Example 3 will be described.

[0042] Table 5 shows lens data for each lens surface of the imaging lens system 11 according to Example 3. The items shown in Table 5 are the same as those in Table 1, and therefore their explanation will be omitted. Furthermore, the imaging lens system 11 according to Example 3 has an F-number of 1.6 and a total angle of view of 82°.

[0043]

[0044] Table 6 shows aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 11 of Example 3. In Table 6, the aspherical shape adopted for the lens surface is expressed by the same formula as in Example 1.

[0045]

[0046] 6A to 6C show diagrams of spherical aberration (longitudinal aberration), field curvature, and distortion in the imaging lens system 11 of Example 3. The explanations for the aberration diagrams shown in Figures 6A to 6C are the same as those for Figures 2A to 2C, and therefore will not be repeated.

[0047] Example 4 FIG. 7 is a cross-sectional view showing a camera module 10 according to Example 4. The imaging lens system 11 according to Example 4 further includes a seventh lens L7 having negative power. In the imaging lens system 11 according to Example 4, the object-side surface S12 of the sixth lens L6 has an aspherical shape with a convex surface facing the object side, and the image-side surface S13 of the sixth lens L6 has an aspherical shape with a convex surface facing the image side. The object-side surface S14 of the seventh lens L7 has an aspherical shape with a concave surface facing the object side, and the image-side surface S15 of the seventh lens L7 has an aspherical shape with a concave surface facing the image side. The configuration of the imaging lens system 11 according to Example 4, other than the sixth lens L6 and the seventh lens L7, is the same as that of Example 1, and therefore a description thereof will be omitted. Below, characteristic data of the imaging lens system 11 according to Example 4 will be described.

[0048] Table 7 shows lens data for each lens surface of the imaging lens system 11 according to Example 4. The items shown in Table 7 are the same as those in Table 1, and therefore their explanation will be omitted. Furthermore, the imaging lens system 11 of Example 4 has an F-number of 1.6 and a total angle of view of 82°.

[0049]

[0050] Table 8 shows aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 11 of Example 4. In Table 8, the aspherical shape adopted for the lens surface is expressed by the same formula as in Example 1.

[0051]

[0052] 8A to 8C show diagrams of spherical aberration (longitudinal aberration), field curvature, and distortion in the imaging lens system 11 of Example 4. The explanation of each aberration diagram shown in Figures 8A to 8C is the same as that of Figures 2A to 2C, and therefore will not be repeated.

[0053] Example 5 Fig. 9 is a cross-sectional view showing a camera module 10 according to Example 5. In the imaging lens system 11 according to Example 5, the aperture stop is disposed between the second lens L2 and the third lens L3. The configuration of the imaging lens system 11 according to Example 5 other than the aperture stop is the same as that of Example 1, and therefore a description thereof will be omitted. Below, characteristic data of the imaging lens system 11 according to Example 5 will be described.

[0054] Table 9 shows lens data for each lens surface of the imaging lens system 11 according to Example 5. The items shown in Table 9 are the same as those in Table 1, and therefore their explanation will be omitted. Furthermore, the imaging lens system 11 according to Example 5 has an F-number of 1.6 and a total angle of view of 82°.

[0055]

[0056] Table 10 shows aspherical coefficients for defining the aspherical shape of the aspherical lens surface in the imaging lens system 11 of Example 5. In Table 10, the aspherical shape adopted for the lens surface is expressed by the same formula as in Example 1.

[0057]

[0058] 10A to 10C show diagrams of spherical aberration (longitudinal aberration), field curvature, and distortion in the imaging lens system 11 of Example 5. The explanations for the aberration diagrams shown in Figures 10A to 10C are the same as those for Figures 2A to 2C, and therefore will not be repeated.

[0059] Table 11 shows 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 focal length f7 of the seventh lens L7, the total optical length TTL, R ｍａｘ / R ０ The value of h Ｒｍａｘ / h ｍａｘ The values ​​of the fourth lens L4, the Abbe number vd4 of the fourth lens L4, the Abbe number vd5 of the fifth lens L5, and the effective image circle diameter / total optical length (De / TLL) are shown in Table 11. In Table 11, the units of the total optical length and focal length are mm. The focal lengths shown in Table 11 were calculated using the e-line.

[0060]

[0061] In Examples 1 to 5, the imaging lens system 11 satisfies the above conditional expressions (1) and (2), thereby suppressing an increase in coma aberration of the first lens L1 due to decentering of the first lens L1 or decentering of the third lens L3 during assembly of the imaging lens system 11. This makes it possible to realize a high-resolution imaging lens system 11. In fact, in Examples 1 to 5, as shown in FIGS. 2A to 2C, 4A to 4C, 6A to 6C, 8A to 8C, and 10A to 10C, various aberrations can be suitably reduced, and the imaging lens system 11 in Examples 1 to 5 has high resolution. Furthermore, in Examples 1 to 5, the F-number is 1.6, and the imaging lens system 11 has sufficient brightness for vehicle sensing.

[0062] In addition, in Examples 1 to 5, the fourth lens L4 having a positive power that satisfies the above conditional expression (3) and the fifth lens L5 having a negative power that satisfies the above conditional expression (4) form a cemented lens, which makes it possible to correct axial chromatic aberration and suppress light loss due to reflection at the cemented surface between the image-side surface of the fourth lens and the object-side surface of the fifth lens.

[0063] Furthermore, in Examples 1 to 5, since the sixth lens L6 has positive power, it is possible to have the sixth lens L6 share the positive power of the entire imaging lens system 11, and the positive power shared by the third lens L3 can be reduced accordingly. As a result, it is possible to suppress an increase in coma aberration of the first lens L1 due to decentering of the third lens L3. In fact, in Examples 1 to 5, various aberrations can be suitably reduced, as shown in Figures 2A to 2C, 4A to 4C, 6A to 4C, 8A to 4C, and 10A to 4C.

[0064] Furthermore, in Examples 1 to 5, the object-side surface S12 and the image-side surface S13 of the sixth lens L6 have aspheric shapes, which makes it possible to correct various aberrations and realize an imaging lens system 11 with good imaging performance. In fact, in Examples 1 to 5, various aberrations can be suitably reduced, as shown in Figures 2A to 2C, 4A to 4C, 6A to 6C, 8A to 8C, and 10A to 10C.

[0065] Furthermore, in Examples 1 to 3 and 5, the image side surface S13 of the sixth lens L6 is concave toward the image side, and in Example 4, the image side surface S15 of the seventh lens L7 is concave toward the image side, and as a result, as shown in Table 11, it is possible to make the effective image circle diameter De sufficiently large compared to the total optical length TTL of the imaging lens system 11.

[0066] Furthermore, in Example 4, the object-side surface S14 and the image-side surface S15 of the seventh lens L7 have aspheric shapes, which makes it possible to correct various aberrations and realize an imaging lens system 11 with good imaging performance. In fact, in Examples 1 to 5, various aberrations can be suitably reduced, as shown in Figures 2A to 2C, 4A to 4C, 6A to 6C, 8A to 8C, and 10A to 10C.

[0067] Furthermore, since the camera module 10 includes the imaging lens system 11, it is possible to provide a high-resolution camera module 10.

[0068] Third Embodiment FIG. 11 is a schematic diagram of a vehicle 40 equipped with an in-vehicle system including an imaging device 50 including an imaging lens system 11 according to the first or second embodiment and an imaging element 12 that converts light collected through 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, and FIG. 11 is an example of an arrangement illustrating the mounting position of the imaging device 50 on the vehicle 40. The imaging device 50 mounted on the vehicle 40 can also be called an in-vehicle camera and can be installed in various locations on the vehicle 40. For example, the first imaging device 50a may be disposed on or near the front bumper as a camera that monitors the front of the vehicle 40 while the vehicle 40 is traveling. The second imaging device 50b that monitors the front of the vehicle 40 may be disposed near an inner rearview mirror inside the vehicle 40. The third imaging device 50c may be disposed on the dashboard, in the instrument panel, or the like as a camera that monitors the driver's driving status. The fourth imaging device 50d may be installed at the rear of the vehicle 40 to monitor the rear of the vehicle 40. The imaging devices 50a and 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 images the left rear side and a right side camera that images the right rear side.

[0069] Image signals of images captured by the imaging device 50 may be output to an information processing device 42 and / or a display device 43 within the vehicle 40. The information processing device 42 and the display device 43, together with the imaging device 50, constitute an in-vehicle system. The information processing device 42 within the vehicle 40 includes a device that processes image signals acquired by the imaging device 50 and recognizes various objects in the captured images to assist the driver in driving. Examples of the information processing device 42 include, but are not limited to, a navigation system, a collision damage mitigation braking system, a vehicle-to-vehicle distance control system, and a lane departure warning system. The display device 43 displays images processed and output by the information processing device 42, but can also receive image signals directly from the imaging device 50. 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 display image signals output from the imaging device 50, which captures images from positions difficult for the driver to view, such as a rear camera, to occupants such as the driver.

[0070] Fig. 12 shows the configuration of an imaging device 50 that constitutes the in-vehicle system of Fig. 11. As shown in the figure, the imaging device 50 according to one embodiment includes a control unit 52, a storage unit 54, and a camera module 10.

[0071] 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 as, for example, a processor. The control unit 52 may also include one or more processors. 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.

[0072] 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 parameters, etc., used by the control unit 52 to perform detection processing based on the captured images. The storage unit 54 may be included in the control unit 52.

[0073] As described above, the camera module 10 captures an image of a subject 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.

[0074] 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 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.

[0075] The imaging data may be read by the camera module 10 for all pixels and captured by the control unit 52 as a captured image. A captured image read by 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 captured as a captured image. In other words, the imaging data may be read from pixels in a predetermined capture range. The imaging data read from pixels in the predetermined capture range may be captured 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 predetermined capture range from the subject image formed via the imaging lens system 11.

[0076] It should be noted that the present invention is not limited to the above-described embodiments, and modifications can be made as appropriate without departing from the spirit of the present invention. For example, the applications of the imaging lens system of the present invention are not limited to vehicle-mounted cameras and surveillance cameras, and it can also be used for other applications, such as being mounted on small electronic devices such as mobile phones.

[0077] This application claims priority based on Japanese Patent Application No. 2024-151641, filed September 3, 2024, the disclosure of which is incorporated herein by reference in its entirety. Possible industrial uses

[0078] It is possible to provide high-resolution imaging lens systems, camera modules, in-vehicle systems, and mobile bodies.

[0079] REFERENCE SIGNS LIST 10 camera module 11 imaging lens system 12 imaging element 40 vehicle (moving body) 42 information processing device (processing device) 43 display device (output device) 50 imaging device 52 control unit L1 first lens L2 second lens L3 third lens L4 fourth lens L5 fifth lens L6 sixth lens L7 seventh lens STOP aperture Gf front group Gr rear group IRCF infrared cut filter IMG imaging surface OA optical axis

Claims

1. A first lens having a convex object-side surface facing the object side and negative power, a second lens having a concave object-side surface facing the object side and negative power, a third lens having a convex object-side surface facing the object side and positive power, and a fourth lens are arranged in this order from the object side to the image side, and an aperture is arranged between the second lens, the third lens, and the fourth lens, the object-side surface of the first lens has an aspherical shape, and the axial radius of curvature of the object-side surface of the first lens is R ０ , the maximum value of the radius of curvature of the object side surface of the first lens is R ｍａｘ , the radius of curvature of the object side surface of the first lens is the maximum value R ｍａｘ The radius at which Ｒｍａｘ , the effective diameter of the object side surface of the first lens is h ｍａｘ When R is defined as follows, the imaging lens system satisfies the following conditional expressions (1) and (2): 1.4<R ｍａｘ / R ０ <1.7...(1) 0.6<h Ｒｍａｘ / h ｍａｘ <0.95 ... (2) 2. The imaging lens system according to claim 1, wherein the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are arranged in this order from the object side to the image side, the fourth lens has positive power, the fifth lens has negative power, and when the Abbe number of the fourth lens for the d-line is defined as vd4 and the Abbe number of the fifth lens for the d-line is defined as vd5, the imaging lens system satisfies the following conditional expressions (3) and (4), and the image-side surface of the fourth lens and the object-side surface of the fifth lens are cemented together: vd4>50 (3) vd5<30 (4) 3. The imaging lens system according to claim 1, characterized in that the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in this order from the object side to the image side, the fourth lens having positive power, the fifth lens having negative power, and the sixth lens having positive power.

4. The imaging lens system according to claim 1, characterized in that the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in this order from the object side to the image side, and the object-side and image-side surfaces of the sixth lens have aspherical shapes.

5. The imaging lens system according to claim 1, wherein the lens positioned closest to the image side among the lenses positioned closer to the image side than the stop has a concave surface facing the image side.

6. The imaging lens system according to claim 1, wherein the object-side and image-side surfaces of the lens positioned closest to the image side among the lenses positioned closer to the image side than the stop have aspherical shapes.

7. A camera module comprising the imaging lens system according to any one of claims 1 to 6 and an imaging element that converts light collected through said imaging lens system into an electrical signal.

8. An in-vehicle system to be mounted on a vehicle, comprising: a camera module according to claim 7; and an information processing device that processes an image output from the imaging element of the camera module and recognizes an object in the image.

9. A mobile body equipped with the on-board system described in claim 8, wherein the on-board system further comprises an output device that outputs information to an occupant, and the information processing device is configured to output the recognition information of the object to the output device.

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