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

Abstract

Provided are an imaging lens system which is compact and has high resolution, a camera module, an in-vehicle system, and a moving body. This imaging lens system (11) comprises, in order from an object side to an image side: a first lens (L1) having a negative power such that an object-side surface thereof has a convex surface facing the object side; a second lens (L2) having a negative power such that an object-side surface thereof has a convex surface facing the object side; a third lens (L3) having a positive power such that an object-side surface thereof has a convex surface facing the object side; a diaphragm STOP; a fourth lens (L4) having a positive power; a fifth lens (L5) having a negative power such that an object-side surface thereof has a convex surface facing the object side; a sixth lens (L6) having a positive power such that an image-side surface thereof has a concave surface facing the image side; and a seventh lens (L7) having a positive power such that an object-side surface thereof has a convex surface facing the object side. The fifth lens (L5) and the sixth lens (L6) constitute a cemented lens having a negative composite power.

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, in-vehicle cameras have been required to have sensing functions for detecting people and objects, leading to higher resolution and larger image sensors. Accordingly, imaging lens systems mounted on in-vehicle cameras and the like have also tended to become larger. Meanwhile, due to the need for omnidirectional sensing of the vehicle's surroundings, in-vehicle cameras are increasingly being mounted in spatially limited locations, such as side mirrors. This has led to a demand for smaller in-vehicle cameras. Furthermore, to reduce the possibility of collisions with stones, gravel, and the like, there is also a demand for smaller first lenses. Patent Document 1 describes a lens system consisting of seven lenses mounted on an in-vehicle camera and the like, in which the diameter of the first lens is relatively small.

[0003] JP 2014-102291 A

[0004] However, in the imaging lens system described in Patent Document 1, the sixth lens is a biconcave lens, so light rays emitted from the sixth lens are directed off-axis. Therefore, in order to reduce the angle of incidence of light rays onto the sensor surface, it is necessary to increase the power of the seventh lens adjacent to the sixth lens. This results in large astigmatism and field curvature in areas with high image heights, deteriorating imaging performance.

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

[0006] An imaging lens system of one embodiment comprises, 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 convex 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, a stop, a fourth lens having positive power, a fifth lens having a convex object-side surface facing the object side and negative power, a sixth lens having a concave image-side surface facing the image side and positive power, and a seventh lens having a convex object-side surface facing the object side and positive power, wherein the fifth lens and the sixth lens form a cemented lens having negative composite power.

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

[0008] 9 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 1. FIG. 10 is a diagram showing spherical aberration (longitudinal aberration) in the imaging lens system according to Example 1. FIG. 11 is a diagram showing curvature of field in the imaging lens system according to Example 1. FIG. 12 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 2. FIG. 13 is a diagram showing spherical aberration (longitudinal aberration) in the imaging lens system according to Example 2. FIG. 14 is a diagram showing curvature of field in the imaging lens system according to Example 2. FIG. 15 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 3. FIG. 16 is a diagram showing spherical aberration (longitudinal aberration) in the imaging lens system according to Example 3. FIG. 17 is a diagram showing curvature of field in the imaging lens system according to Example 3. FIG. 18 is a cross-sectional view showing the configuration of a camera module and an imaging lens system according to Example 4. FIG. 19 is a diagram showing spherical aberration (longitudinal aberration) in the imaging lens system according to Example 4. FIG. 19 is a diagram showing curvature of field in the imaging lens system according to Example 4. FIG. 19 is a schematic diagram of a vehicle on which an in-vehicle system equipped with a camera module according to an embodiment of the present invention is mounted. FIG. 19 is a block diagram showing 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 a highly reliable system, particularly in a sensing system, ensuring healthy lives and promoting well-being for all people of all ages, and target "3.6: By 2020, halve the number of global road traffic deaths and injuries." of "3. Good health and well-being" in the Sustainable Development Goals (SDGs) advocated by the United Nations. The present embodiments also contribute to the development of resilient infrastructure, and target "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." of "9. Industry, innovation and infrastructure." of the Sustainable Development Goals (SDGs) advocated by the United Nations. (Embodiment 1: Imaging Lens System) An imaging lens system according to Embodiment 1 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 convex 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, a stop, a fourth lens having positive power, a fifth lens having a convex object-side surface facing the object side and negative power, a sixth lens having a concave image-side surface facing the image side and positive power, and a seventh lens having a convex object-side surface facing the object side, wherein the fifth and sixth lenses form a cemented lens having negative composite power.

[0010] This makes it possible to provide a compact imaging lens system with high resolution. Specifically, because the sixth lens is a meniscus lens with a concave surface facing the image side, the angle of off-axial light rays at a field angle emitted from the sixth lens relative to the optical axis can be reduced. Therefore, even if the power of the seventh lens adjacent to the sixth lens is reduced, the angle of light rays incident on the sensor surface can be reduced. In addition, the occurrence of astigmatism and field curvature in areas with high image heights can be suppressed, thereby maintaining good imaging performance. Furthermore, because the power of the seventh lens is small, the error sensitivity of the seventh lens can also be reduced. Therefore, it is possible to provide a compact imaging lens system with high resolution.

[0011] It is also preferable that the image-side surface of the seventh lens has an inflection point. By having an inflection point on the image-side surface of the seventh lens, it is possible to suitably correct curvature of field in the seventh lens and realize a high-resolution imaging lens system.

[0012] Furthermore, when the radius of curvature of the object-side surface of the first lens is defined as L1R1 and the distance on the optical axis from the vertex of the object-side surface of the first lens to the aperture stop is defined as L1-STOP, the imaging lens system preferably satisfies the following conditional expression (1): L1R1 / (L1-STOP)<2.0 (1) When the imaging lens system satisfies the above conditional expression (1), the curvature of the object-side surface of the first lens can be made tighter, and the angle of incidence of light rays incident on the first lens can be made gentler. This makes it possible to minimize astigmatism generated on the object-side surface of the first lens. This makes it possible to maintain good imaging performance throughout the entire field of view. If the value of L1R1 / (L1-STOP) is 2.0 or greater, the curvature of the object-side surface of the first lens becomes gentler, and the angle of incidence of light rays incident on the first lens becomes steeper, resulting in large astigmatism being generated on the object-side surface of the first lens. The value of L1R1 / (L1-STOP) is more preferably 1.80 or less, 1.70 or less, and even more preferably 1.60 or less.

[0013] Furthermore, when the composite focal length of the lens group located on the object side of the aperture stop is defined as FGF, and the distance on the optical axis from the vertex of the object-side surface of the first lens to the aperture stop is defined as L1-STOP, it is preferable to satisfy the following conditional expression (2): 2.0<|(L1-STOP) / FGF|<3.0 (2) When the imaging lens system satisfies the above conditional expression (2), it is possible to more reliably achieve a compact imaging lens system. Specifically, in order to reduce the diameter of the first lens, it is necessary to increase the power of the front group (the lens group located on the object side of the aperture stop) of the imaging lens system. However, if the power of the front group is too great, distortion will become too large, and in order to correct this distortion, it is necessary to increase the size of the rear group (the lens group located on the object side of the aperture stop). Therefore, if the value of |(L1-STOP) / FGF| is less than 2.0, the power of the front group will be small, i.e., the composite focal length of the front group will be long, resulting in a large diameter of the first lens. On the other hand, if the value of |(L1-STOP) / FGF| is greater than 3.0, the power of the front group will be too great, causing excessive distortion, and it will be necessary to make the rear group larger to correct the distortion. The value of |(L1-STOP) / FGF| is more preferably 2.3 or greater and 2.5 or less, and even more preferably 2.35 or greater and 2.45 or less.

[0014] Furthermore, when the focal length of the entire imaging lens system is defined as F and the combined focal length of the fifth and sixth lenses is defined as F56, it is preferable that the imaging lens system satisfy the following conditional expression (3): 5.0<|F56 / F|<12.0 (3) When the imaging lens system satisfies the above conditional expression (3), not only axial chromatic aberration and lateral chromatic aberration but also higher-order components of spherical aberration, astigmatism, and field curvature can be suitably corrected, thereby realizing a high-resolution imaging lens system. When the value of |F56 / F| is 5.0 or less, the spherical aberration and field curvature are biased to the under side (increased in the negative direction). On the other hand, when the value of |F56 / F| is 12.0 or more, the spherical aberration and field curvature are biased to the over side (increased in the positive direction). The value of |F56 / F| is more preferably 5.5 or more and 10.5 or less, and even more preferably 6.5 or more and 8.5 or less. In a cemented lens, if the difference in refractive index between the cemented surfaces is small, the critical angle can be made large, making it difficult for total reflection to occur. This allows the curvature of the cemented surfaces to be made tight, making it possible to correct spherical aberration, astigmatism, and higher-order components of field curvature.

[0015] Furthermore, when the focal length of the entire imaging lens system is defined as F and the composite focal length of the lens group located closer to the object than the aperture stop is defined as FGF, it is preferable that the following conditional expression (4) be satisfied: 2.0<|FGF / F|<3.5 (4) When the imaging lens system satisfies the above conditional expression (4), a compact imaging lens system with high resolution can be realized while ensuring sufficient back focus. Specifically, when the value of |FGF / F| is 2.0 or less, the spherical aberration, coma, and lateral chromatic aberration generated in the front group become large, and the rear group must be enlarged to correct the spherical aberration, coma, and lateral chromatic aberration. On the other hand, when the value of |FGF / F| is 3.5 or more, the power of the front group becomes small, and the front group must be enlarged to correct field curvature and distortion while ensuring sufficient back focus. The value of |FGF / F| is more preferably 2.2 or more and 2.7 or less, and even more preferably 2.3 or more and 2.7 or less.

[0016] Furthermore, when the composite focal length of the lens group located on the object side of the aperture stop is defined as FGF and the composite focal length of the lens group located on the image side of the aperture stop is defined as RGF, it is preferable that the imaging lens system satisfies the following conditional expression (5): 0.9<|FGF / RGF|<1.5 (5) When the imaging lens system satisfies the above conditional expression (5), a balance can be achieved between compactness and high resolution of the imaging lens. Specifically, when the value of |FGF / RGF| is 0.9 or less, the spherical aberration, coma, and lateral chromatic aberration generated in the front group become large, and the rear group needs to be enlarged to correct the spherical aberration, coma, and lateral chromatic aberration. On the other hand, when the value of |FGF / RGF| is 1.5 or more, the power of the front group becomes small, and the front group needs to be enlarged to correct field curvature and distortion while ensuring sufficient back focus. The value of |FGF / RGF| is more preferably 0.94 or more and 1.1 or less, and even more preferably 0.95 or more and 1.0 or less.

[0017] (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. This makes it possible to provide a compact, high-resolution camera module.

[0018] 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).

[0019] The image sensor 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 image sensor 12 is disposed at the image forming position (focal position) of the imaging lens system 11.

[0020] 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, a sixth lens L6, and a seventh lens L7. 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.

[0021] The first lens L1 is a meniscus lens having negative 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.

[0022] The second lens L2 is a meniscus lens having negative power. The object-side surface S3 of the second lens L2 has an aspheric shape with a convex surface facing the object side. The image-side surface S4 of the second lens L2 has an aspheric shape with a concave surface facing the image side.

[0023] The third lens L3 is a meniscus lens having positive power. The object-side surface S5 of the third lens L3 has an aspheric shape with a convex surface facing the object side. The image-side surface S6 of the third lens L3 also has an aspheric shape with a concave surface facing the image side.

[0024] 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.

[0025] 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.

[0026] The fifth lens L5 is a meniscus lens having negative power. The object-side surface S10 of the fifth lens L5 has an aspheric shape with a convex surface facing the object side. The image-side surface S11 of the fifth lens L5 has an aspheric shape with a concave surface facing the image side.

[0027] The sixth lens L6 is a meniscus lens having 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 also has an aspheric shape with a concave surface facing the image side.

[0028] The seventh lens L7 has positive power. The object-side surface S14 of the seventh lens L7 has an aspheric shape with a convex surface facing the object side. The image-side surface S15 of the seventh lens L7 also has an aspheric shape with a convex surface facing the image side.

[0029] 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 seventh lens L7. 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.

[0030] 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 radius of curvature (mm) of each surface, 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 2.0 and a total angle of view (2ω) of 210°.

[0031]

[0032] 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 ray height from the optical axis OA, and the aspherical coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th orders are respectively α４ , α ６ , α ８ , α １０ , α １２ , α １４ , α １６ When this is the case, it is expressed by the following equation:

[0033] 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, "-5.54772E-03" corresponds to "-5.54772×10 －３ The same applies to the numerical expressions in the following tables.

[0034]

[0035] Next, aberrations will be described with reference to the drawings. FIGS. 2A and 2B show spherical aberration diagrams (longitudinal aberration diagrams) and field curvature diagrams for the imaging lens system 11 of Example 1. In the longitudinal aberration diagram of FIG. 2A, the horizontal axis indicates the position where a light ray intersects with the optical axis OA, and the vertical axis indicates the passing height of the light ray on the entrance pupil. FIG. 2A also shows simulation results for the F', e, and C' lines. In the field curvature diagram of FIG. 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 FIG. 2B, Sag indicates the image formation position for a sagittal ray bundle, and Tan indicates the image formation position for a tangential ray bundle. FIG. 2B also shows simulation results for the e-line.

[0036] 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.

[0037] 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 of Example 2 has an F-number of 2.0 and a total angle of view (2ω) of 210°.

[0038]

[0039] 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.

[0040]

[0041] 4A and 4B show spherical aberration diagrams (longitudinal aberration diagrams) and field curvature diagrams in the imaging lens system 11 of Example 2. The explanations for the aberration diagrams shown in Figs. 4A and 4B are the same as those for Figs. 2A and 2B, and therefore will not be repeated.

[0042] 5 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 configuration as that of Example 1, and therefore its description will be omitted. The characteristic data of the imaging lens system 11 according to Example 3 will be described below.

[0043] 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 2.0 and a total angle of view (2ω) of 210°.

[0044]

[0045] 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.

[0046]

[0047] 6A and 6B show diagrams of spherical aberration (longitudinal aberration) and field curvature in the imaging lens system 11 of Example 3. The explanations of the aberration diagrams shown in Figs. 6A and 6B are the same as those in Figs. 2A and 2B, and therefore will not be repeated.

[0048] 7 is a cross-sectional view showing a camera module 10 according to Example 4. The configuration of the imaging lens system 11 according to Example 4 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.

[0049] 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 2.0 and a total angle of view (2ω) of 210°.

[0050]

[0051] 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.

[0052]

[0053] 8A and 8B show diagrams of spherical aberration (longitudinal aberration) and field curvature in the imaging lens system 11 of Example 4. The explanations of the aberration diagrams shown in Figs. 8A and 8B are the same as those in Figs. 2A and 2B, and therefore will not be repeated.

[0054] Table 9 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 composite focal length F56, the composite focal length FGF, the composite focal length RGF, the value of L1R1 / (L1-STOP), the value of |(L1-STOP) / FGF|, the value of |F56 / F|, the value of |FGF / F|, and the value of |FGF / RGF|. In Table 9, the focal lengths are calculated using the e-line, and the units are mm.

[0055]

[0056] In Examples 1 to 4, the sixth lens L6 is a meniscus lens, which makes it possible to provide a compact and high-resolution imaging lens system 11. Specifically, in Examples 1 to 4, various aberrations can be suitably reduced as shown in Figures 2A, 2B, 4A, 4B, 6A, 6B, 8A, and 8B. Therefore, in Examples 1 to 4, the imaging lens system 11 has high resolution. Furthermore, in Examples 1 to 4, the total angle of view (2ω) is 210°, and the imaging lens system 11 has a wide angle of view that is sufficiently wide for vehicle sensing.

[0057] Furthermore, in Examples 1 to 4, the value of L1R1 / (L1-STOP) satisfies the above-mentioned conditional expression (1), so that the curvature of the object-side surface of the first lens L1 can be made tight, and astigmatism generated on the object-side surface of the first lens can be kept small, thereby maintaining good imaging performance over the entire field of view.

[0058] Furthermore, in Examples 1 to 4, the value of |(L1-STOP) / FGF| satisfies the above conditional expression (2), so that the imaging lens system can be made more compact with more certainty.

[0059] Furthermore, in Examples 1 to 4, the value of |F56 / F| satisfies the above-mentioned conditional expression (3), so that not only axial chromatic aberration and chromatic aberration of magnification but also spherical aberration, astigmatism, and higher-order components of field curvature can be suitably corrected, thereby realizing a high-resolution imaging lens system. In fact, in Examples 1 to 4, various aberrations can be suitably reduced, as shown in Figures 2A, 2B, 4A, 4B, 6A, 6B, 8A, and 8B.

[0060] Furthermore, in Examples 1 to 4, the value of |FGF / F| satisfies the above-mentioned conditional expression (4), so that a compact, high-resolution imaging lens system can be realized while ensuring a sufficient back focus. In fact, in Examples 1 to 4, various aberrations can be suitably reduced, as shown in Figures 2A, 2B, 4A, 4B, 6A, 6B, 8A, and 8B.

[0061] Furthermore, in Examples 1 to 4, the value of |FGF / RGF| satisfies the above-mentioned conditional expression (5), thereby achieving a balance between compactness and high resolution of the imaging lens. In fact, in Examples 1 to 4, various aberrations can be suitably reduced, as shown in Figures 2A, 2B, 4A, 4B, 6A, 6B, 8A, and 8B.

[0062] Furthermore, since the camera module 10 includes the imaging lens system 11, it is possible to provide a compact and high-resolution camera module 10.

[0063] Third Embodiment FIG. 9 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. 9 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 installed 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 installed near an inner rearview mirror inside the vehicle 40. The third imaging device 50c may be installed on the dashboard or in the instrument panel 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 can include 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.

[0064] 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.

[0065] Fig. 10 shows the configuration of an imaging device 50 that constitutes the in-vehicle system of Fig. 9. 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] This application claims priority based on Japanese Patent Application No. 2023-123126, filed on July 28, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0073] It is possible to provide a compact and high-resolution imaging lens system, a camera module, an in-vehicle system, and a mobile object.

[0074] 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. An imaging lens system comprising, in order from the object side to the image side, a first lens having negative power and a convex surface on the object side facing the object side, a second lens having negative power and a convex surface on the object side facing the object side, a third lens having positive power and a convex surface on the object side facing the object side, a stop, a fourth lens having positive power, a fifth lens having negative power and a convex surface on the object side facing the object side, a sixth lens having positive power and a concave surface on the image side facing the image side, and a seventh lens having positive power and a convex surface on the object side facing the object side, wherein the fifth lens and the sixth lens form a cemented lens having negative composite power.

2. The imaging lens system according to claim 1, wherein the image side surface of the seventh lens has an inflection point.

3. The imaging lens system according to claim 1, characterized in that, when the radius of curvature of the object-side surface of the first lens is defined as L1R1 and the distance on the optical axis from the apex of the object-side surface of the first lens to the aperture is defined as L1-STOP, the imaging lens system satisfies the following conditional expression (1): L1R1 / (L1-STOP)<2.0 (1) 4. The imaging lens system according to claim 1, wherein the following conditional expression (2) is satisfied when a composite focal length of a lens group located on the object side of the aperture is defined as FGF, and a distance on the optical axis from a vertex of the object side surface of the first lens to the aperture is defined as L1-STOP: 2.0<|(L1-STOP) / FGF|<3.0 ... (2) 5. The imaging lens system according to claim 1, wherein the following conditional expression (3) is satisfied when the focal length of the entire imaging lens system is defined as F and the composite focal length of the fifth lens and the sixth lens is defined as F56: 5.0<|F56 / F|<12.0 (3) 6. The imaging lens system according to claim 1, wherein the imaging lens system satisfies the following conditional expression (4), where F is the focal length of the entire system of the imaging lens system, and FGF is the composite focal length of the lens group located on the object side with respect to the aperture stop. 2.0<|FGF / F|<3.5 (4) 7. The imaging lens system according to claim 1, wherein the following conditional expression (5) is satisfied when a composite focal length of a lens group located on the object side of the aperture stop is defined as FGF, and a composite focal length of a lens group located on the image side of the aperture stop is defined as RGF: 0.9<|FGF / RGF|<1.5 (5) 8. A camera module comprising the imaging lens system according to any one of claims 1 to 7, and an imaging element for converting light focused through said imaging lens system into an electrical signal.

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

10. A moving body equipped with the on-board system described in claim 9, wherein the on-board system further comprises an output device for outputting information to an occupant, and the information processing device is configured to output recognition information of the object to the output device.

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