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

Abstract

We provide bright, high-resolution imaging lens systems, camera modules, in-vehicle systems, and mobile devices. [Solution] The imaging lens system 11 consists of substantially seven lenses in order from the object side to the image side: a front group Gf, an aperture stop, and a rear group Gr. It comprises a first lens L1 with negative power whose image side faces concave toward the image side, a second lens L2 with object side faces convex toward the object side, a third lens L3 with positive power, a fourth lens L4 with image side faces convex toward the image side, a fifth lens L5 with image side faces concave toward the image side, a sixth lens L6 with positive power and a biconvex shape, and a seventh lens L7 with negative power, satisfying the following conditions (1) to (3). -5.0 <f1 / f<-2.0 ···(1) -7.0 <f5 / f<-4.0 ···(2) 3.0

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes a small optical system that has a wide angle of view and high optical performance and is suitable for imaging devices such as digital still cameras, video cameras, surveillance cameras, and in-vehicle cameras.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the lens system described in Patent Document 1, the F-number is 4.12, and the brightness is insufficient for sensing in bad weather such as at night, rain, or fog.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a bright and high-resolution imaging lens system, camera module, in-vehicle system, and moving body.

Means for Solving the Problems

[0006] In one embodiment of the imaging lens system, the system consists of substantially seven lenses arranged in order from the object side to the image side: a front group, an aperture diaphragm, and a rear group, comprising: a first lens with negative power having a concave surface on its image side facing the image side; a second lens with a convex surface on its object side facing the object side; a third lens with positive power; a fourth lens with a convex surface on its image side facing the image side; a fifth lens with a concave surface on its image side facing the image side; a sixth lens with positive power having a convex surface on both its object and image sides facing the image side; and a seventh lens with negative power. When the focal length of the first lens is defined as f1, the focal length of the fifth lens as f5, the combined focal length of the fifth, sixth, and seventh lenses as f567, and the focal length of the entire optical system as f, the following conditions (1) to (3) are satisfied. -5.0 <f1 / f<-2.0 ···(1) -7.0 <f5 / f<-4.0 ···(2) 3.0 <f567 / f<10.0 ···(3) [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a bright, high-resolution imaging lens system, camera module, in-vehicle system, and mobile device. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 1. [Figure 2] These are the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, distortion diagram, and chromatic aberration diagram for the imaging lens system of Example 1. [Figure 3] This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 2. [Figure 4] These are the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, distortion diagram, and chromatic aberration diagram for the imaging lens system of Example 2. [Figure 5] This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Embodiment 3. [Figure 6]These are the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, distortion diagram, and chromatic aberration diagram for the imaging lens system of Example 3. [Figure 7] This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Embodiment 4. [Figure 8] These are the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, distortion diagram, and chromatic aberration diagram for the imaging lens system of Example 4. [Figure 9] This is a schematic diagram of a vehicle equipped with an in-vehicle system that includes a camera module according to one embodiment of the present invention. [Figure 10] Figure 9 is a block diagram showing the configuration of the imaging device that makes up the in-vehicle system. [Modes for carrying out the invention]

[0009] The embodiments of the present invention will be described below with reference to the drawings. These embodiments are particularly capable of realizing highly reliable systems in sensing systems and contribute to the development of resilient infrastructure. They target "9. Build resilient infrastructure, including local and transboundary infrastructure, to support economic development and human well-being, with a focus on affordable and equitable access for all," which is part of the United Nations' Sustainable Development Goals (SDGs). (Embodiment 1: Imaging lens system) The imaging lens system according to Embodiment 1 consists of substantially seven lenses arranged in order from the object side to the image side: a front group, an aperture diaphragm, and a rear group, comprising: a first lens with negative power having a concave surface on its image side facing the image side; a second lens with a convex surface on its object side facing the object side; a third lens with positive power; a fourth lens with a convex surface on its image side facing the image side; a fifth lens with a concave surface on its image side facing the image side; a sixth lens with positive power having a convex surface on its object side and a convex surface on its image side facing the image side; and a seventh lens with negative power. When the focal length of the first lens is defined as f1, the focal length of the fifth lens is defined as f5, the combined focal length of the fifth, sixth, and seventh lenses is defined as f567, and the focal length of the entire optical system is defined as f, the following conditional expressions (1) to (3) are satisfied. -5.0 < f1 / f < -2.0 ···(1) -7.0 < f5 / f < -4.0 ···(2) 3.0 < f567 / f < 10.0 ···(3)

[0010] Thereby, a bright and high-resolution imaging lens system can be provided. Specifically, when the angle of view of the imaging lens system is widened, the diameter of the light incident on the imaging lens system becomes thicker, the effective radius of the lens for light rays becomes larger, and particularly aberration correction in the peripheral portion within the effective radius of the lens for light rays becomes necessary. Here, the "effective radius of the light rays" is the distance from the optical axis to the maximum peripheral light ray passing through the lens surface. Similarly, when the F value (F number, Fno) is decreased, the effective radius of the lens for light rays becomes larger, and particularly aberration correction in the peripheral portion within the effective radius of the lens for light rays becomes necessary. By satisfying the above conditional expression (1), various aberrations such as field curvature and distortion aberration can be corrected, and an imaging lens system with high resolution, sufficient brightness, and angle of view can be realized. More specifically, when the value of f1 / f is -2.0 or more, the power of the first lens is too strong, and various aberrations such as field curvature and distortion aberration in the peripheral portion within the effective radius of the first lens are excessively corrected. On the other hand, when the value of f1 / f is -5.0 or less, the power of the first lens is too weak, and various aberrations such as field curvature and distortion aberration in the peripheral portion within the effective radius of the first lens cannot be sufficiently corrected. The lower limit value of f1 / f is more preferably -4.7, and even more preferably -4.6. Also, the upper limit value of f1 / f is more preferably -2.2, and even more preferably -2.4. In addition, by satisfying the above conditional expression (2) with the imaging lens system, chromatic aberration can be corrected, and an imaging lens system with high resolution, sufficient brightness, and an adequate angle of view can be realized. Specifically, when the value of f5 / f is -4.0 or more, the power of the fifth lens is too strong, overcorrecting the axial chromatic aberration and lateral chromatic aberration, and making it impossible to reduce the F number. On the other hand, when the value of f5 / f is -7.0 or less, the power of the fifth lens is too weak, making it impossible to sufficiently correct the axial chromatic aberration and lateral chromatic aberration, and making it impossible to reduce the F number. The lower limit value of f5 / f is more preferably -6.9, and even more preferably -6.7. Also, the upper limit value of f5 / f is more preferably -4.2, and even more preferably -4.4. In addition, by satisfying the above conditional expression (3) with the imaging lens system, lateral chromatic aberration can be corrected, and an imaging lens system with high resolution, sufficient brightness, and an adequate angle of view can be realized. Specifically, when the value of f567 / f is 3.0 or less, the combined power of the fifth to seventh lenses is too strong, overcorrecting the lateral chromatic aberration and making it impossible to reduce the F number. On the other hand, when the value of f567 / f is 10.0 or more, the combined power of the fifth to seventh lenses is too weak, making it impossible to sufficiently correct the lateral chromatic aberration and making it impossible to reduce the F number. The lower limit value of f567 / f is more preferably 3.2, and even more preferably 3.4. Also, the upper limit value of f567 / f is more preferably 9.8, and even more preferably 9.6. Therefore, by satisfying the conditional expressions (1) to (3) with the imaging lens system, it is possible to provide an imaging lens system that has sufficient brightness for sensing inside and outside a vehicle at night or in bad weather, has a wide angle of view, and has high resolution.

[0011] In addition, the fifth lens, the sixth lens, and the seventh lens preferably form a cemented lens. When the fifth lens, the sixth lens, and the seventh lens form a cemented lens, it becomes possible to correct lateral chromatic aberration, and an imaging lens system with high resolution, sufficient brightness, and an adequate angle of view can be realized.

[0012] Furthermore, when the focal length of the fourth lens is defined as f4, it is preferable that the following condition (4) is satisfied. 2.0 <f4 / f<3.0 ···(4) By satisfying the above condition equation (4), the imaging lens system can compensate for the amount of focus shift in the imaging lens system due to temperature changes. Specifically, if the value of f4 / f is 2.0 or less, the power of the fourth lens is too strong, and the correction of the amount of focus shift in the imaging lens system due to temperature changes becomes excessive. On the other hand, if the value of f4 / f is 3.0 or more, the power of the fourth lens is too weak, and it becomes impossible to adequately correct the amount of focus shift in the imaging lens system due to temperature changes. The lower limit of f4 / f is more preferably 2.05, 2.10, and even more preferably 2.15. The upper limit of f4 / f is more preferably 2.95, 2.90, and even more preferably 2.85.

[0013] Furthermore, the first and fourth lenses are preferably glass lenses. Because the first lens is a glass lens, it is possible to provide an imaging lens system that is resistant to scratches and has excellent weather resistance against oil stains. Furthermore, by setting the temperature coefficient dNd4 / dt of the relative refractive index of the fourth lens to a suitable value, it becomes possible to compensate for the amount of focus shift caused by changes in ambient temperature using the fourth lens.

[0014] Furthermore, the second, third, fifth, sixth, and seventh lenses are preferably made of plastic. The fact that the second, third, fifth, sixth, and seventh lenses are made of plastic reduces manufacturing costs.

[0015] Furthermore, when the combined focal length of the first lens, the second lens, and the third lens is defined as f123, it is preferable that the following condition (5) is satisfied. -3.0 <f123 / f<-1.0 ···(5) By satisfying the above condition equation (5), the imaging lens system can correct distortion and lateral aberration, thereby realizing a high-resolution imaging lens system. Specifically, if the value of f123 / f is -1.0 or higher, the combined power of the first to third lenses is too strong, resulting in excessive correction of distortion and lateral aberration. On the other hand, if the value of f123 / f is -3.0 or lower, the combined power of the first to third lenses is too weak, resulting in insufficient correction of distortion and lateral aberration. The lower limit of f123 / f is more preferably -2.9, and even more preferably -2.7. The upper limit of f123 / f is more preferably -1.2, and even more preferably -1.4.

[0016] Furthermore, when the Abbe number for the d line of the fifth lens is defined as νd5, the Abbe number for the d line of the sixth lens is defined as νd6, and the Abbe number for the d line of the seventh lens is defined as νd7, it is preferable that the following condition (6) is satisfied. 0.0<νd6-(νd5+νd7)<30.0 (6) By satisfying the above condition (6) in the imaging lens system, chromatic aberration can be corrected, and an imaging lens system with high resolution and sufficient brightness and field of view can be realized. Specifically, if the value of νd6-(νd5+νd7) is 30 or more, chromatic aberration will be overcorrected. On the other hand, if the value of νd6-(νd5+νd7) is 0.0 or less, chromatic aberration cannot be sufficiently corrected. The lower limit of νd6-(νd5+νd7) is more preferably 2.0, and even more preferably 4.0. The upper limit of νd6-(νd5+νd7) is more preferably 28.0, and even more preferably 26.0.

[0017] Furthermore, when the total optical length of the imaging lens system is defined as TTL, it is preferable that the following condition (7) is satisfied. Here, the total optical length of the imaging lens system is the distance along the optical axis from the side surface of the object to the image plane of the first lens of the imaging lens system. TTL / f < 9.5 ···(7) By satisfying the above condition (7), the overall optical length of the imaging lens system can be shortened, and the imaging lens system can be made compact enough to be mounted in a spatially restricted position such as a side mirror. Specifically, if the TTL / f value is 9.5 or higher, it is not possible to reliably miniaturize the imaging lens system. On the other hand, if the TTL / f value is 6.0 or lower, it becomes necessary to miniaturize each lens, which increases the difficulty of manufacturing, worsens the manufacturing yield, and increases component costs. The lower limit of TTL / f is more preferably 6.5, and even more preferably 7.0. The upper limit of TTL / f is more preferably 9.0, and even more preferably 8.5.

[0018] Furthermore, when the half-angle of view of the imaging lens system is defined as ω, it is preferable that the following condition (8) is satisfied. ω>90° ···(8) By satisfying the above condition (8), the imaging lens system can be realized with a wide field of view, high resolution, and sufficient brightness and field of view. The lower limit of ω is more preferably 100°.

[0019] Furthermore, when the temperature coefficient of the relative refractive index at the d line of the fourth lens is defined as dNd4 / dt, it is preferable that the following condition (9) is satisfied in the range of 20°C to 40°C. dNd4 / dt(×10 -6 / ℃)<4.5 ···(9) By satisfying the above condition (9) in the imaging lens system, the fourth lens can compensate for the amount of focus shift caused by changes in ambient temperature. In other words, by selecting a material for the fourth lens such that dNd4 / dt satisfies condition (9), the amount of focus shift caused by temperature changes can be corrected. Specifically, by dNd4 / dt satisfying condition (9), the amount of focus shift caused by temperature changes in the fourth lens itself can offset the difference between the linear expansion coefficients of the barrel and the holder, and the amount of focus shift caused by temperature changes in the distance from the object-side surface of the first lens to the image-forming surface of the image sensor. As a result, the fourth lens can correct the amount of focus shift of the entire imaging lens system due to temperature changes.

[0020] (Embodiment 2: Camera Module) The camera module according to Embodiment 2 comprises the above-described imaging lens system and an image sensor positioned at the focal point of the imaging lens system, which converts the light collected through the imaging lens system into an electrical signal. This makes it possible to provide a bright, high-resolution camera module.

[0021] Next, embodiments 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) Figure 1 is a cross-sectional view showing the configuration of the camera module 10 of Embodiment 1. Specifically, the camera module 10 comprises an imaging lens system 11 and an image sensor 12. The imaging lens system 11 and the image sensor 12 are housed in a housing (not shown).

[0022] The image sensor 12 is an element that converts received light into an electrical signal, and for example, a CCD image sensor or a CMOS image sensor is used. The image sensor 12 is positioned at the imaging position (focal position) of the imaging lens system 11.

[0023] The imaging lens system 11 according to Embodiment 1 consists of a front group Gf comprising a first lens L1, a second lens L2, and a third lens L3, arranged in order from the object side to the image side; an aperture diaphragm (STOP); and a rear group Gr comprising a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7. The first lens L1 and the fourth lens L4 are glass lenses. The second lens L2, the third lens L3, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are plastic lenses. The image plane of the imaging lens system 11 is shown as IMG. Furthermore, an optical filter (such as an infrared transmission filter, a visible / infrared bandpass filter, or an infrared cut filter) may be placed 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 placed between the imaging lens system 11 and the image sensor 12 will be described.

[0024] The first lens L1 is a meniscus lens with negative power. The object side S1 of the first lens L1 has a spherical shape with a convex surface facing the object. The image side S2 of the first lens L1 has a spherical shape with a concave surface facing the image.

[0025] The second lens L2 has negative power. The object side S3 of the second lens L2 has an aspherical shape with a convex surface facing the object. The image side S4 of the second lens L2 has an aspherical shape with a concave surface facing the image.

[0026] The third lens L3 has positive power. The object side S5 of the third lens L3 has an aspherical shape with a convex surface facing the object. The image side S6 of the third lens L3 has an aspherical shape with a concave surface facing the image.

[0027] The aperture stop is the aperture that determines the F-number (Fno) of the lens system. The aperture stop is located between the third lens L3 and the fourth lens L4.

[0028] The fourth lens L4 has positive power. The object side S9 of the fourth lens L4 has a spherical shape with a concave surface facing the object. The image side S10 of the fourth lens L4 has a spherical shape with a convex surface facing the image.

[0029] The fifth lens L5 has negative power. The object side S11 of the fifth lens L5 has an aspherical shape with a convex surface facing the object. The image side S12 of the fifth lens L5 has an aspherical shape with a concave surface facing the image.

[0030] The sixth lens L6 has positive power. The object side S13 of the sixth lens L6 has an aspherical shape with a convex surface facing the object. Also, the image side S14 of the sixth lens L6 has an aspherical shape with a convex surface facing the image.

[0031] The seventh lens L7 has negative power. The object side S15 of the seventh lens L7 has an aspherical shape with a concave surface facing the object. The image side S16 of the seventh lens L7 has an aspherical shape with a convex surface facing the image.

[0032] The fifth lens L5, the sixth lens L6, and the seventh lens L7 constitute a cemented lens. Specifically, the image side S12 of the fifth lens L5 is in contact with the object side S13 of the sixth lens L6, and the image side S14 of the sixth lens L6 is in contact with the object side S15 of the seventh lens L7. Furthermore, the fifth lens L5 and the sixth lens L6, and the sixth lens L6 and the seventh lens L7 are joined together by an adhesive layer with an axial thickness of 0.020 mm.

[0033] An infrared cut filter (IRCF) is a filter used to cut out 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 located on the image side of the lens that is positioned closest to the image, that is, on the image side of the seventh lens L7 in Example 1. Furthermore, a sensor cover glass may be placed between the infrared cut filter and the image sensor 12 to prevent dust from adhering to the image sensor 12.

[0034] Table 1 shows the lens data for each lens surface in the imaging lens system 11 of Example 1. In Table 1, the lens data for each surface includes the radius of curvature on the axis (mm), the interplanar spacing on the optical axis OA (mm), the refractive index nd for the d line, the Abbe number νd for the d line, and the effective ray radius (mm). 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 field of view of 210°.

[0035] [Table 1]

[0036] The aspherical shapes used on the lens surface are determined by using α4, α6, α8, and α8 aspherical coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order, respectively, where Z is the sag amount, c is the reciprocal of the radius of curvature, k is the conicity coefficient, and r is the height from the optical axis OA. 10 , α 12 , α 14 , α 16 When this is the case, it can be expressed by the following equation.

number

[0037] Table 2 shows the aspheric coefficients used to define the aspheric shape of the aspheric lens surface in the imaging lens system 11 of Example 1. Note that in Table 2, for example, "-1.970021E-02" is equivalent to "-1.970021×10 -2 This means "[...]." The numerical representation is the same for the following table.

[0038] [Table 2]

[0039] Next, aberrations will be explained using diagrams. Figure 2 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, distortion diagram, and chromatic aberration diagram for the imaging lens system 11 of Example 1. Furthermore, in the longitudinal aberration diagram of Figure 2(A), the horizontal axis indicates the position where the light ray intersects the optical axis OA, and the vertical axis indicates the relative height of the light ray above the entrance pupil. Figure 2(A) also shows the simulation results for the d, g, and C lines. Furthermore, in the field curvature diagram of Figure 2(B), the horizontal axis represents the distance in the direction of the optical axis OA, and the vertical axis represents the image height (field of view). Also, in the field curvature diagram of Figure 2(B), Sag represents the imaging position in the sagittal beam, and Tan represents the imaging position in the tangential beam. Figure 2(B) also shows the simulation results for the d-line. Furthermore, in the distortion aberration diagram in Figure 2(C), the horizontal axis represents the image distortion aberration (%), and the vertical axis represents the image height (field of view). Figure 2(C) also shows the simulation results at line d. Furthermore, in the chromatic aberration diagram of Figure 2(D), the horizontal axis represents the amount of chromatic aberration, and the vertical axis represents the image height (angle of view). Figure 2(D) also shows the simulation results using the d-line, g-line, and C-line.

[0040] (Example 2) Figure 3 is a cross-sectional view showing the 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, so its explanation will be omitted. The characteristic data of the imaging lens system 11 according to Example 2 will be described below.

[0041] Table 3 shows the 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, so their explanations are omitted. In addition, the imaging lens system 11 of Example 2 has an F-number of 2.0 and a total field of view of 210°.

[0042] [Table 3]

[0043] Table 4 shows the aspheric coefficients used to define the aspherical shape of the lens surface designated as aspherical 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.

[0044] [Table 4]

[0045] Figure 4 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, distortion diagram, and chromatic aberration diagram for the imaging lens system 11 of Example 2. The explanation of each aberration diagram shown in Figure 4 is the same as in Figure 2, so the explanation is omitted.

[0046] (Example 3) Figure 5 is a cross-sectional view showing the camera module 10 according to Embodiment 3. The configuration of the imaging lens system 11 according to Embodiment 3 is the same as that of Embodiment 1, so its explanation will be omitted. The characteristic data of the imaging lens system 11 according to Embodiment 3 will be described below.

[0047] Table 5 shows the 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, so their explanations are omitted. In addition, the imaging lens system 11 of Example 3 has an F-number of 2.0 and a total field of view of 210°.

[0048] [Table 5]

[0049] Table 6 shows the aspheric coefficients used to define the aspherical shape of the lens surface designated as aspherical 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.

[0050] [Table 6]

[0051] Figure 6 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, distortion diagram, and chromatic aberration diagram for the imaging lens system 11 of Example 3. The explanation of each aberration diagram shown in Figure 6 is the same as in Figure 2, so the explanation is omitted.

[0052] (Example 4) Figure 7 is a cross-sectional view showing the camera module 10 according to Embodiment 4. The configuration of the imaging lens system 11 according to Embodiment 4 is the same as that of Embodiment 1, so its explanation will be omitted. The characteristic data of the imaging lens system 11 according to Embodiment 4 will be described below.

[0053] Table 7 shows the 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, so their explanations are omitted. In addition, the imaging lens system 11 of Example 4 has an F-number of 2.0 and a total field of view of 210°.

[0054] [Table 7]

[0055] Table 8 shows the aspheric coefficients used to define the aspherical shape of the lens surface designated as aspherical 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.

[0056] [Table 8]

[0057] Figure 8 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, distortion diagram, and chromatic aberration diagram for the imaging lens system 11 of Example 4. The explanation of each aberration diagram shown in Figure 8 is the same as in Figure 2, so the explanation is omitted.

[0058] Table 9 shows the total focal length f 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 value of f1 / f, the value of f5 / f, the value of f567 / f, the value of f4 / f, the value of f123 / f, the value of νd6-(νd5+νd7), TTL / f, the value of half-angle of view (ω), and dNd4 / dt(×10 -6 The values ​​shown are ( / °C). In Table 9, the units for optical length and focal length are mm, and the unit for field of view is °. Furthermore, the focal lengths shown in Table 9 were calculated using the d-line.

[0059] [Table 9]

[0060] In Examples 1 to 4, by satisfying the above-mentioned conditions (1) to (3), the imaging lens system 11 can be provided with sufficient brightness for sensing inside and outside the vehicle at night or in bad weather, and with a wide field of view and high resolution. In fact, in Examples 1 to 4, as shown in Figures 2, 4, 6, and 8, various aberrations are suitably reduced. Therefore, in Examples 1 to 4, the imaging lens system 11 has high resolution. Furthermore, in Examples 1 to 4, the field of view is 210° or more, and the F-number is 2.0, thus realizing a wide-angle and bright imaging lens system 11 in Examples 1 to 4.

[0061] Furthermore, in Examples 1 to 4, the fifth lens L5, the sixth lens L6, and the seventh lens L constitute a cemented lens, which makes it possible to correct chromatic aberration, thereby realizing an imaging lens system 11 with high resolution, sufficient brightness, and a wide field of view. In fact, in Examples 1 to 4, as shown in Figures 2, 4, 6, and 8, chromatic aberration is suitably reduced.

[0062] Furthermore, in Examples 1 to 4, by satisfying the above condition (4) of the imaging lens system 11, it becomes possible to compensate for the amount of focus shift of the imaging lens system due to temperature changes. This makes it possible to realize an imaging lens system 11 with high resolution. In fact, in Examples 1 to 4, as shown in Figures 2, 4, 6, and 8, various aberrations are suitably reduced.

[0063] Furthermore, in Examples 1 to 4, the first lens L1 being a glass lens provides an imaging lens system 11 that is resistant to scratches and has excellent weather resistance against oil stains. Also, the fourth lens L4 being a glass lens allows the fourth lens L4 to compensate for the amount of focus shift due to changes in ambient temperature by setting the temperature coefficient dNd4 / dt of the relative refractive index of the fourth lens L4 to a suitable value. Specifically, in Examples 1 to 4, by satisfying conditional equation (9), the fourth lens L4 can compensate for the amount of focus shift due to changes in ambient temperature. Table 10 shows the amount of focus shift (μm) of the imaging lens system 11 of Examples 1 to 4 with respect to changes in ambient temperature at focal length f. Table 10 shows the amount of focus shift from focal length f at room temperature of 25°C. The barrel and housing material used to calculate the amount of focus shift for focal length f shown in Table 10 is XYRON XP640 manufactured by Asahi Kasei Corporation. The focal lengths shown in Table 10 were calculated using the d line. [Table 10]

[0064] Furthermore, since the second lens L2, third lens L3, fifth lens L5, sixth lens L6, and seventh lens L7 are made of plastic, the manufacturing cost of the imaging lens system 11 can be reduced.

[0065] Furthermore, in Examples 1 to 4, by satisfying the above condition (5) of the imaging lens system 11, distortion and lateral aberration can be corrected, and a high-resolution imaging lens system 11 can be realized. In fact, as shown in Figures 2, 4, 6, and 8, distortion is suitably reduced.

[0066] Furthermore, in Examples 1 to 4, by satisfying the above condition (6) of the imaging lens system 11, chromatic aberration can be corrected, and an imaging lens system with high resolution, sufficient brightness, and field of view can be realized. In fact, in Examples 1 to 4, as shown in Figures 2, 4, 6, and 8, various aberrations are suitably reduced.

[0067] Furthermore, in Examples 1 to 4, by satisfying the above condition (7) of the imaging lens system 11, the overall optical length of the imaging lens system 11 can be shortened, and the imaging lens system 11 can be made into an optical system that is compact enough to be mounted in a spatially limited position such as a side mirror.

[0068] Furthermore, in Examples 1 to 4, the value of the half-angle of view ω satisfies the above condition (8), and the imaging lens system 11 has a wide angle of view sufficient for sensing inside and outside the vehicle.

[0069] Furthermore, by providing the camera module 10 with an imaging lens system 11, a high-resolution camera module 10 can be provided.

[0070] (Embodiment 3) Figure 9 is a schematic diagram of a vehicle 40 equipped with an in-vehicle system comprising an imaging device 50 including an imaging lens system 11 according to Embodiment 1 or Embodiment 2 and an image sensor 12 that converts the light focused through the system into an electrical signal. As shown in the figure, the imaging device 50 can be mounted on the vehicle 40, and Figure 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 placed on or near the front bumper as a camera to monitor the area in front of the vehicle 40 while it is in motion. The second imaging device 50b, which also monitors the area in front, may be placed near the rearview mirror inside the vehicle 40. The third imaging device 50c may be placed on the dashboard or inside the instrument panel, etc., as a camera to monitor the driver's driving condition. The fourth imaging device 50d may be installed at the rear of the vehicle 40 for use as a rear monitor. 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.

[0071] The image signal of the image captured by the imaging device 50 can be output to an information processing device 42 and / or a display device 43, etc., within the vehicle 40. These information processing devices 42 and 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 the image signal acquired by the imaging device 50 and recognizes various objects in the captured image to assist the driver in driving. The information processing device 42 also includes, but is not limited to, a navigation device, a collision damage mitigation braking device, a distance control device, and a lane departure warning device. The display device 43 displays the image processed and output by the information processing device 42, but can also receive the image signal directly from the imaging device 50. The display device 43 may employ, but is not limited to, a liquid crystal display (LCD), an organic electro-luminescence (EL) display, and an inorganic EL display. The display device 43 can display the image signal output from the imaging device 50, which captures images from positions that are difficult for the driver to see, such as a rear camera, to the driver or other occupants.

[0072] Figure 10 shows the configuration of the imaging device 50 that constitutes the in-vehicle system shown in Figure 9. As shown in the figure, the imaging device 50 according to one embodiment comprises a control unit 52, a storage unit 54, and a camera module 10.

[0073] 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. This control unit 52 may be configured as a processor, for example. The control unit 52 may also include one or more processors. The processors may include general-purpose processors that load a specific program and execute a specific function, and dedicated processors specialized for specific processing. Dedicated processors may include application-specific integrated circuits (ICs). Application-specific integrated circuits are also called ASICs (Application Specific Integrated Circuits). The processors may also include programmable logic devices. Programmable logic devices are also called PLDs (Programmable Logic Devices). PLDs may include field-programmable gate arrays (FPGAs). 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 cooperate.

[0074] The storage unit 54 stores various information or parameters related to the operation of the imaging device 50. The storage unit 54 may be composed of, for example, a semiconductor memory. 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., for 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.

[0075] As mentioned above, the camera module 10 captures the subject image formed via the imaging lens system 11 with the image sensor 12 and outputs the captured image. The image captured by the camera module 10 is also called the captured image.

[0076] The image sensor 12 may be composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device). The image sensor 12 has an imaging surface in which multiple pixels are arranged. Each pixel outputs a signal that is specified by current or voltage according to the amount of incident light. The signal output by each pixel is also called imaging data.

[0077] The imaging data may be read out by the camera module 10 for all pixels and taken into the control unit 52 as an image. The image obtained by reading out all pixels is also called the maximum image. The imaging data may be read out by the camera module 10 for some pixels and taken into the image. In other words, the imaging data may be read out from pixels within a predetermined acquisition range. The imaging data read out from pixels within a predetermined acquisition range may be taken into the image. The predetermined acquisition range may be set by the control unit 52. The camera module 10 may obtain the predetermined acquisition range from the control unit 52. The image sensor 12 may capture an image within a predetermined acquisition range from the subject image formed via the imaging lens system 11.

[0078] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the applications of the imaging lens system of the present invention are not limited to in-vehicle cameras and surveillance cameras, but can also be used for other applications such as mounting on small electronic devices such as mobile phones. [Explanation of Symbols]

[0079] 10 Camera Modules 11 Imaging lens system 12 Image sensor 40 Vehicles (mobile vehicles) 42. Information Processing Device (Processing Device) 43 Display device (output device) 50 Imaging device 52 Control Unit L1 First Lens L2 Second Lens L3 3rd lens L4 4th lens L5 5th lens L6 6th lens L7 7th lens STOP aperture Gf front group Gr rear group IRCF infrared cut filter IMG imaging plane OA optical axis

Claims

1. The lens consists of essentially seven lenses arranged in order from the object side to the image side: a front group, an aperture diaphragm, and a rear group. These lenses include a first lens with negative power (concave on the image side), a second lens with positive power (convex on the object side), a third lens with positive power, a fourth lens with concave on the image side, a fifth lens with concave on the image side, a sixth lens with positive power (convex on both the object and image sides), and a seventh lens with negative power. When the focal length of the first lens is defined as f1, the focal length of the fifth lens as f5, the combined focal length of the fifth lens, the sixth lens, and the seventh lens as f567, and the focal length of the entire optical system as f, the following conditions (1) to (3) are satisfied, the optical system is characterized by satisfying these conditions. Imaging lens system. -5.0<f1 / f<-2.0...(1) -7.0<f5 / f<-4.0...(2) 3.0<f567 / f<10.0...(3)

2. The imaging lens system according to claim 1, characterized in that the fifth lens, the sixth lens, and the seventh lens constitute a cemented lens.

3. When the focal length of the fourth lens is defined as f4, the following condition (4) is satisfied, The imaging lens system according to claim 1. 2.0<f4 / f<3.0...(4)

4. The imaging lens system according to claim 1, wherein the first lens and the fourth lens are glass lenses.

5. The imaging lens system according to claim 1, wherein the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens are plastic lenses.

6. The imaging lens system according to claim 1, characterized in that when the combined focal length of the first lens, the second lens, and the third lens is defined as f123, the following conditional expression (5) is satisfied. -3.0<f123 / f<-1.0...(5)

7. The imaging lens system according to claim 1, characterized in that it satisfies the following condition (6) when the Abbe number of the fifth lens with respect to the d line is defined as νd5, the Abbe number of the sixth lens with respect to the d line is defined as νd6, and the Abbe number of the seventh lens with respect to the d line is defined as νd7. 0.0<νd6-(νd5+νd7)<30.0...(6)

8. The imaging lens system according to claim 1, characterized in that it satisfies the following condition (7) when the total optical length of the imaging lens system is defined as TTL. TTL / f<9.5...(7)

9. The imaging lens system according to claim 1, characterized in that when the half-angle of view of the imaging lens system is defined as ω, the following condition (8) is satisfied. ω>90°...(8)

10. The imaging lens system according to claim 1, characterized in that, when the temperature coefficient of the relative refractive index of the fourth lens at the d line is defined as dNd4 / dt, the following conditional equation (9) is satisfied in the range of 20°C to 40°C. dNd4 / dt(×10 －６ / ℃)<4.5 ・・・(9)

11. A camera module comprising an imaging lens system according to any one of claims 1 to 10, and an image sensor that converts light focused through the imaging lens system into an electrical signal.

12. An in-vehicle system installed in a vehicle, The camera module according to claim 11, An information processing device that processes the captured image output from the image sensor of the camera module to recognize an object in the captured image, An in-vehicle system characterized by having the following features.

13. A mobile body equipped with the vehicle-mounted system described in claim 12, The in-vehicle system further includes an output device that outputs information to the occupants, The mobile body is characterized in that the information processing device is configured to output recognition information of the object to the output device.

Images