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

Abstract

We provide an imaging lens system, camera module, in-vehicle system, and mobile device with sufficient field of view and brightness for sensing inside and outside a vehicle at night or in adverse weather conditions. [Solution] The imaging lens system 11 consists of a front group Gf, an aperture diaphragm STOP, and a rear group Gr, comprising a first lens L1 with negative power whose image side faces concave toward the image, a second lens L2 with object side faces concave toward the object, a third lens L3 with positive power, a fourth lens L4 with power, a fifth lens L5 with power, a sixth lens L6 with power, and a seventh lens L7 with power. Among the lenses with positive power from the first lens L1 to the seventh lens L7, the third lens L3 has the greatest power, and when the focal length of the first lens L1 is defined as f1 and the focal length of the entire optical system is defined as f, the following condition (1) is satisfied. -2.5

Description

Technical Field

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

Background Art

[0002] In recent years, as an in-vehicle sensing camera, it is required to have a sufficient viewing angle to acquire information on the road ahead of the vehicle and the vehicle. Further, in order to enable sensing in bad weather such as at night, rain, or fog, it is required to have sufficient brightness as a camera. Patent Document 1 describes a lens system of an in-vehicle sensing camera composed of seven lenses, having an F number of 1.59 to 1.66 and an overall viewing angle of 116° to 123°.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the imaging lens system described in Patent Document 1, since the overall viewing angle is 116° to 123°, the viewing angle is insufficient for performing wide-range sensing of pedestrians and objects on the sidewalk, signal information within an intersection, etc. Further, in the lens system described in Patent Document 1, the viewing angle is narrow for acquiring information on the driver in the vehicle, the passenger in the front passenger seat, and the passengers in the rear seats. Also, in the imaging lens system described in Patent Document 1, since the F number is 1.59 to 1.66, the brightness is insufficient for sensing in bad weather such as at night, rain, or fog.

[0005] This invention has been made in view of the above problems, and aims to provide an imaging lens system, camera module, in-vehicle system, and mobile device having a field of view and brightness sufficient for sensing inside and outside a vehicle at night or in bad weather. [Means for solving the problem]

[0006] One embodiment of the imaging lens 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 whose image side faces concave toward the image side, a second lens with object side facing concave toward the object side, a third lens with positive power, a fourth lens with positive power, a fifth lens with positive power, a sixth lens with positive power, and a seventh lens with positive power. Of the lenses from the first to the seventh, among those with positive power, the third lens has the greatest power. When the focal length of the first lens is defined as f1 and the focal length of the entire optical system as f, the following condition (1) is satisfied. -2.5 <f1 / f<-1.0 ···(1) [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an imaging lens system, camera module, in-vehicle system, and mobile body having a field of view and brightness sufficient for sensing inside and outside a vehicle at night or in adverse weather conditions. [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, and distortion 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, and distortion 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, and distortion aberration diagram for the imaging lens system of Example 3. [Figure 7] 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 8] Figure 7 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 capable of realizing highly reliable systems, particularly 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 one 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 whose image side faces concave toward the image side, a second lens with object side facing concave toward the object side, a third lens with positive power, a fourth lens with power, a fifth lens with power, a sixth lens with power, and a seventh lens with power. Of the lenses from the first to the seventh, among those with positive power, the third lens has the greatest power. When the focal length of the first lens is defined as f1 and the focal length of the entire optical system as f, the following condition (1) is satisfied. -2.5 <f1 / f<-1.0 ···(1)

[0010] This makes it possible to provide an imaging lens system with a sufficient field of view and brightness for sensing inside and outside the vehicle at night or in bad weather. Specifically, widening the field of view of the imaging lens system increases the diameter of light incident on the system, increasing the effective ray radius of the lens, and requiring aberration correction, especially in the peripheral areas within the effective ray radius. Here, "effective ray radius" is the distance from the optical axis to the maximum peripheral ray passing through the lens surface. Similarly, decreasing the F-number (F-number, Fno) increases the effective ray radius of the lens, requiring aberration correction, especially in the peripheral areas within the effective ray radius. By satisfying the above condition (1), various aberrations such as field curvature and distortion can be corrected, and an imaging lens system with high resolution and sufficient brightness and field of view can be realized. More specifically, when the f1 / f value is -1.0 or greater, the power of the first lens is too strong, and various aberrations such as field curvature and distortion in the peripheral areas within the effective ray radius of the first lens are overcorrected. On the other hand, if the value of f1 / f is -2.5 or less, the power of the first lens is too weak, and various aberrations such as field curvature and distortion in the peripheral part within the effective radius of the first lens cannot be adequately corrected. The lower limit of f1 / f is more preferably -2.3, and even more preferably -2.0. The upper limit of f1 / f is more preferably -1.2, and even more preferably -1.4. Therefore, by satisfying condition (1), the imaging lens system can be provided with an imaging lens system having a sufficient field of view and brightness for sensing inside and outside the vehicle at night or in bad weather.

[0011] Furthermore, among the lenses from the first to the seventh lens, the third lens has the greatest positive power, which makes it possible to compensate for the amount of focus shift in the imaging lens system due to temperature changes. Specifically, since the third lens is a glass lens with a relatively small coefficient of linear expansion, even if the positive power of the third lens is stronger than that of the other positive power lenses, it is possible to reduce the influence that the third lens has on the amount of focus shift in the imaging lens system due to changes in ambient temperature.

[0012] Also, when the combined focal length of the first lens and the second lens is defined as f12, it is preferable that the imaging lens system satisfies the following conditional expression (2). -2.0 < f12 / f < -0.5 ···(2) By the imaging lens system satisfying the above conditional expression (2), in the first lens and the second lens, distortion aberration and lateral aberration can be suitably corrected, and an imaging lens system with high resolution, sufficient brightness, and a sufficient angle of view can be realized. When the value of f12 / f is -2.0 or less, the combined power of the first lens and the second lens is too strong, and the distortion aberration and lateral aberration are over-corrected. On the other hand, when the value of f12 / f is -0.5 or more, the combined power of the first lens and the second lens is too weak, and the distortion aberration and lateral aberration cannot be sufficiently corrected. The lower limit value of f12 / f is more preferably -1.8, and even more preferably -1.6. Also, the upper limit value of f12 / f is more preferably -0.8, and even more preferably -0.9.

[0013] Also, when the focal length of the third lens is defined as f3, it is preferable that the imaging lens system satisfies the following conditional expression (3). 1.0 < f3 / f < 2.0 ···(3) By the imaging lens system satisfying the above conditional expression (3), in the third lens, spherical aberration and lateral aberration can be suitably corrected, and an imaging lens system with high resolution, sufficient brightness, and a sufficient angle of view can be realized. Specifically, when the value of f3 / f is 1.0 or less, the focal length of the third lens is too short with respect to the focal length of the entire optical system. In other words, the positive power of the third lens is too strong, and the spherical aberration and lateral aberration are over-corrected. On the other hand, when the value of f3 / f is 2.0 or more, the focal length of the third lens is too long with respect to the focal length of the entire optical system. In other words, the positive power of the third lens is too weak, and the spherical aberration and lateral aberration cannot be sufficiently corrected. The lower limit value of f3 / f is more preferably 1.1, and even more preferably 1.3. Also, the upper limit value of f3 / f is more preferably 1.9, and even more preferably 1.7.

[0014] Furthermore, it is preferable that the imaging lens system satisfies the following condition (4) when the focal length of the fourth lens is defined as f4. |f4 / f|>5 ···(4) If the imaging lens system satisfies the above condition (4), the power of the fourth lens becomes too strong, making it difficult to compensate for the amount of focus shift of the imaging lens system due to temperature changes. Specifically, since the fourth lens is a plastic lens with a relatively large coefficient of linear expansion, if the power of the fourth lens becomes too strong, the influence of the fourth lens on the amount of focus shift of the imaging lens system due to changes in ambient temperature becomes large. The lower limit of |f4 / f| is more preferably 5.2, and even more preferably 5.3.

[0015] Furthermore, it is preferable that the imaging lens system satisfies the following condition (5) when the focal length of the fifth lens is defined as f5. |f5 / f|>5 ···(5) If the imaging lens system satisfies the above condition (5), the power of the fifth lens becomes too strong, making it difficult to compensate for the amount of focus shift of the imaging lens system due to temperature changes. Specifically, since the fifth lens is a plastic lens with a relatively large coefficient of linear expansion, if the power of the fifth lens becomes too strong, the influence of the fifth lens on the amount of focus shift of the imaging lens system due to changes in ambient temperature becomes large. The lower limit of |f5 / f| is more preferably 5.3, and even more preferably 5.6.

[0016] Furthermore, it is preferable that the imaging lens system satisfies the following condition (6) when the focal length of the sixth lens is defined as f6. 2.0 <f6 / f<4.0 ···(6) By satisfying the above condition (6) in the imaging lens system, distortion and lateral aberration can be suitably corrected in the sixth lens, and an imaging lens system with high resolution and sufficient brightness and field of view can be realized. Specifically, when the value of f6 / f is 2.0 or less, the focal length of the sixth lens is too short relative to the focal length of the entire optical system, in other words, the positive power of the sixth lens is too strong, and distortion and lateral aberration are overcorrected. On the other hand, when the value of f6 / f is 4.0 or more, the focal length of the sixth lens is too long relative to the focal length of the entire optical system, in other words, the positive power of the sixth lens is too weak, and distortion and lateral aberration cannot be sufficiently corrected. The lower limit of f6 / f is more preferably 2.2, and even more preferably 2.4. The upper limit of f6 / f is more preferably 3.8, and even more preferably 3.6.

[0017] Furthermore, it is preferable that the imaging lens system satisfies the following condition (7) when the focal length of the seventh lens is defined as f7. 5.0 <f7 / f<20 ···(7) By satisfying the above condition (7) in the imaging lens system, distortion and lateral aberration can be suitably corrected in the sixth lens, and an imaging lens system with high resolution, sufficient brightness, and field of view can be realized. Specifically, when the value of f7 / f is 5.0 or less, the focal length of the seventh lens is too short relative to the focal length of the entire optical system; in other words, the positive power of the seventh lens is too strong, resulting in excessive correction of distortion and lateral aberration. On the other hand, when the value of f7 / f is 20 or more, the focal length of the seventh lens is too long relative to the focal length of the entire optical system; in other words, the positive power of the seventh lens is too weak, resulting in insufficient correction of distortion and lateral aberration. The lower limit of f7 / f is more preferably 6.0, and even more preferably 7.0. The upper limit of f7 / f is more preferably 18.0, and even more preferably 16.0.

[0018] Furthermore, it is preferable that the imaging lens system satisfies the following condition (8) when the total optical length of the imaging lens system is defined as TTL. TTL / f < 6.0 ···(8) This makes it possible to create a compact optical system for the imaging lens system, which is necessary for the optical system of an in-vehicle camera that is mounted in a spatially limited position such as a side mirror.

[0019] Furthermore, in the imaging lens system, the first lens and the third lens are preferably glass lenses. By using a glass lens for the first 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 using a glass lens with a relatively small linear expansion coefficient for the third lens, the power of the third lens can be made stronger compared to other lenses with positive power.

[0020] Furthermore, it is preferable that the second, fourth, fifth, sixth, and seventh lenses are plastic lenses. By using plastic lenses for the second, fourth, fifth, sixth, and seventh lenses, manufacturing costs can be reduced.

[0021] Furthermore, it is preferable that the imaging lens system satisfies the following condition (9) when the design wavelength of the imaging lens system is defined as WL. 800nm <WL<1000nm ···(9) By satisfying the above condition (9), the imaging lens system can detect infrared light, enabling sensing at night or in adverse weather conditions.

[0022] Furthermore, it is preferable that the imaging lens system satisfies the following condition (10) when the half-angle of view of the imaging lens system is defined as ω. ω>80° ···(10) By satisfying the above condition (10), the imaging lens system can be realized with a wide angle of view, high resolution, and sufficient brightness and angle of view.

[0023] (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 camera module with a field of view and brightness sufficient for sensing inside and outside a vehicle at night or in bad weather.

[0024] 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).

[0025] 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.

[0026] The imaging lens system 11 according to Embodiment 1 consists of a front group Gf consisting of a first lens L1 and a second lens L2, an aperture diaphragm (STOP), and a rear group Gr consisting of a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7, in order from the object side to the image side. The image plane of the imaging lens system 11 is shown as IMG. The first lens L1 and the third lens L3 are glass lenses. The second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are plastic lenses. Furthermore, an optical filter (such as an infrared transmission filter or a visible / infrared bandpass 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 transmission filter (FILTER) is placed between the imaging lens system 11 and the image sensor 12 will be described.

[0027] 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.

[0028] The second lens L2 is a meniscus lens with negative power. The object side S3 of the second lens L2 has an aspherical shape with a concave surface facing the object. The image side S4 of the second lens L2 has an aspherical shape with a convex surface facing the image.

[0029] The aperture stop is the aperture that determines the F-number (Fno) of the lens system. The aperture stop is located between the second lens L2 and the third lens L3.

[0030] The third lens L3 is a positive power lens. The object side S7 of the third lens L3 has a spherical shape with the concave side facing the object. The image side S8 of the third lens L3 has a spherical shape with the convex side facing the image.

[0031] The fourth lens L4 is a meniscus lens with negative power. The object side S9 of the fourth lens L4 has an aspherical shape with a concave surface facing the object. The image side S10 of the fourth lens L4 has an aspherical shape with a convex surface facing the image.

[0032] The fifth lens L5 is a positive power lens. 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.

[0033] The sixth lens L6 is a positive power lens. 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.

[0034] The seventh lens, L7, is a positive power lens. 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.

[0035] An infrared transmission filter (FILTER) is a filter that transmits light in the near-infrared region and cuts out light in the visible light region. When designing the imaging lens system 11, the infrared transmission filter is treated as an integral part of the imaging lens system 11. However, the infrared transmission filter is not an essential component of the imaging lens system 11. The infrared transmission filter is located on the image side of the seventh lens L7. Furthermore, a sensor cover glass may be placed between the infrared transmission filter and the image sensor 12 to prevent dust from adhering to the image sensor 12.

[0036] 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 (mm), the interplanar spacing (mm) at the optical axis OA, the refractive index n850 for the design wavelength of 850 nm, 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 1.30 and a half-angle of view (ω) of 80.0°.

[0037] [Table 1]

[0038] 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

[0039] 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, "-1.018295E-04" is equivalent to "-1.018295×10 -4 This means "[...]." The numerical representation is the same for the following table.

[0040] [Table 2]

[0041] Next, aberrations will be explained using diagrams. Figure 2 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, and distortion 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 an 850 nm light ray. 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 an 850 nm beam. Furthermore, in the distortion diagram of Figure 2(C), the horizontal axis represents the image distortion (%), and the vertical axis represents the image height (field of view). Figure 2(C) also shows the simulation results for 850 nm light.

[0042] (Example 2) Figure 3 is a cross-sectional view showing the camera module 10 according to Embodiment 2. In the imaging lens system 11 according to Embodiment 2, the third lens L3 has positive power, the object side surface S7 has a spherical shape with a convex surface facing the object, and the image side surface S8 has a spherical shape with a convex surface facing the image. The configuration of the imaging lens system 11 according to Embodiment 2, other than the third lens L3, is the same as the lens configuration in Embodiment 1, so its explanation is omitted. The characteristic data of the imaging lens system 11 according to Embodiment 2 will be described below.

[0043] 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 1.20 and a half-angle of view (ω) of 80.2°.

[0044] [Table 3]

[0045] 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.

[0046] [Table 4]

[0047] Figure 4 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, and distortion 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.

[0048] (Example 3) Figure 5 is a cross-sectional view showing the camera module 10 according to Embodiment 3. In the imaging lens system 11 according to Embodiment 3, the fourth lens L4 has positive power, the object side surface S9 has an aspherical shape with a convex surface facing the object, and the image side surface S10 has an aspherical shape with a convex surface facing the image. In addition, the fifth lens L5 has negative power, the object side surface S11 has an aspherical shape with a convex surface facing the object, and the image side surface S12 has an aspherical shape with a concave surface facing the image. The configuration of the imaging lens system 11 according to Embodiment 3, other than the fourth lens L4 and the fifth lens L5, has the same lens configuration as in Embodiment 2, so its description is omitted. The characteristic data of the imaging lens system 11 according to Embodiment 3 will be described below.

[0049] Table 5 shows the lens data for each lens surface of the imaging lens system 11 according to Example 3. In Table 5, the refractive index n940 for the design wavelength 940 nm light ray is shown instead of the refractive index n850 for the 850 nm light ray. The other items shown in Table 5 are the same as in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 3 has an F-number of 1.24 and a half-angle of view (ω) of 86.0°.

[0050] [Table 5]

[0051] 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.

[0052] [Table 6]

[0053] Figure 6 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, and distortion aberration diagram for the imaging lens system 11 of Example 3. Figures 6(A) to 6(C) show the simulation results for a 940 nm light ray. Further explanations of each aberration diagram shown in Figure 6 are the same as in Figure 2, and are therefore omitted.

[0054] Table 7 shows the F-number, total field of view (2ω), focal length f of the entire optical system of the imaging lens system 11, focal length f1 of the first lens L1, focal length f2 of the second lens L2, focal length f3 of the third lens L3, focal length f4 of the fourth lens L4, focal length f5 of the fifth lens L5, focal length f6 of the sixth lens L6, focal length f7 of the seventh lens L7, the combined focal length of the first lens L1 and the second lens L2 as f12, the values ​​of f1 / f, f2 / f, f12 / f, f3 / f, |f4 / f|, |f5 / f|, f6 / f, f7 / f, WL value, and half field of view (ω) of the imaging lens system 11. In Table 7, the unit of focal length is mm. The focal lengths shown in Table 7 were calculated using a design wavelength of 850 nm in Examples 1 and 2, and a design wavelength of 940 nm in Example 3.

[0055] [Table 7]

[0056] In Examples 1 to 3, by satisfying condition (1), the imaging lens system 11 can be provided with a field of view and brightness sufficient for sensing inside and outside the vehicle at night or in bad weather. Specifically, in Examples 1 to 3, the F value is 1.30 or less, and the imaging lens system 11 has sufficient brightness. Also, in Examples 1 to 3, as shown in Figures 2, 4, and 6, various aberrations can be suitably reduced. Therefore, in Examples 1 to 3, the imaging lens system 11 has high resolution. In addition, in Examples 1 to 3, the half-angle of view (ω) is 80.0° to 86.0°, and the imaging lens system 11 has a wide field of view sufficient for sensing inside and outside the vehicle.

[0057] Furthermore, in Examples 1 to 3, the fact that the third lens L3 is a glass lens allows for sufficient suppression of focus shift due to changes in ambient temperature. Also, in Examples 1 to 3, the third lens L3 has the largest positive power in the imaging lens system 11, and the imaging lens system 11 satisfies conditions (4) and (5), allowing for sufficient suppression of focus shift due to changes in ambient temperature. Table 8 shows the amount of focus shift (μm) of the imaging lens system 11 in Examples 1 to 3 with respect to changes in ambient temperature at focal length f. Table 8 shows the amount of focus shift along the optical axis from focal length f at room temperature of 25°C. The material of the barrel and housing used to calculate the amount of focus shift for focal length f shown in Table 8 is XYRON XP640 manufactured by Asahi Kasei Corporation. As shown in Table 8, in Examples 1 to 3, the amount of focus shift due to changes in ambient temperature is sufficiently suppressed. The amount of focus shift for focal length f shown in Table 8 was calculated using a design wavelength of 850 nm in Examples 1 and 2, and a design wavelength of 940 nm in Example 3. [Table 8]

[0058] Furthermore, in Examples 1 to 3, since the value of f12 / f satisfies the above condition (2), various aberrations such as distortion and lateral aberration can be suitably corrected in the first lens and the second lens L2. In fact, in Examples 1 to 3, as shown in Figures 2, 4, and 6, various aberrations can be suitably reduced.

[0059] Furthermore, in Examples 1 to 3, by satisfying the above condition (3) for the value of f3 / f, various aberrations such as spherical aberration and lateral aberration can be suitably corrected in the third lens L3. In fact, in Examples 1 to 3, as shown in Figures 2, 4, and 6, various aberrations can be suitably reduced.

[0060] Furthermore, in Examples 1 to 3, since the value of f6 / f satisfies the above conditional equation (6), various aberrations such as distortion and lateral aberration can be suitably corrected in the sixth lens L6. In fact, in Examples 1 to 3, as shown in Figures 2, 4, and 6, various aberrations can be suitably reduced.

[0061] Furthermore, in Examples 1 to 3, since the value of f7 / f satisfies the above conditional equation (7), various aberrations such as distortion and lateral aberration can be suitably corrected in the seventh lens L7. In fact, in Examples 1 to 3, as shown in Figures 2, 4, and 6, various aberrations can be suitably reduced.

[0062] Furthermore, in Examples 1 to 3, the fact that the TTL / f value satisfies the above condition (8) makes it possible to make the imaging lens system 11 a compact optical system necessary for the optical system of an in-vehicle camera that is mounted in a spatially limited position such as a side mirror.

[0063] Furthermore, in Examples 1 to 3, the value of WL satisfies the above condition (9), enabling the detection of infrared light and allowing sensing at night or in adverse weather conditions.

[0064] Furthermore, in Examples 1 to 3, the value of the half-angle of view ω satisfies the above condition (10), and the imaging lens system 11 has a wide angle of view sufficient for sensing inside and outside the vehicle.

[0065] Furthermore, by providing the camera module 10 with an imaging lens system 11, it is possible to provide a camera module 10 with a sufficient field of view and brightness for sensing inside and outside the vehicle at night or in bad weather.

[0066] (Embodiment 3) Figure 7 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 collected through it into an electrical signal. As shown in the figure, the imaging device 50 can be mounted on the vehicle 40, and Figure 7 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 when 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.

[0067] 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.

[0068] Figure 8 shows the configuration of the imaging device 50 that constitutes the in-vehicle system shown in Figure 7. 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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 imaging lens system of the present invention is not limited to in-vehicle cameras or surveillance cameras, but can also be used for other applications such as being mounted on small electronic devices such as mobile phones. [Explanation of Symbols]

[0075] 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 FILTER Infrared Transmission Filter IMG imaging plane OA optical axis

Claims

1. Arranged from the object side towards the image side, the lens consists of essentially seven lenses: a front group, an aperture diaphragm, and a rear group. These consist of a first lens with negative power (its image-side concave towards the image), a second lens with positive power (its object-side concave towards the object), a third lens with positive power, a fourth lens with positive power, a fifth lens with positive power, a sixth lens with positive power, and a seventh lens with positive power. Of the lenses from the first to the seventh, among the lenses having positive power, the third lens has the greatest power. When the focal length of the first lens is defined as f1 and the focal length of the entire optical system as f, the following condition (1) is satisfied, Imaging lens system. -2.5<f1 / f<-1.0...(1)

2. The imaging lens system according to claim 1, characterized in that when the combined focal length of the first lens and the second lens is defined as f12, the following condition (2) is satisfied. -2.0<f12 / f<-0.5...(2)

3. When the focal length of the third lens is defined as f3, the following condition (3) is satisfied, The imaging lens system according to claim 1. 1.0<f3 / f<2.0...(3)

4. The imaging lens system according to claim 1, characterized in that when the focal length of the fourth lens is defined as f4, the following condition (4) is satisfied. |f4 / f|>5...(4)

5. The imaging lens system according to claim 1, characterized in that when the focal length of the fifth lens is defined as f5, the following condition (5) is satisfied. |f5 / f|>5...(5)

6. The imaging lens system according to claim 1, characterized in that when the focal length of the sixth lens is defined as f6, the following condition (6) is satisfied. 2.0<f6 / f<4.0...(6)

7. The imaging lens system according to claim 1, characterized in that when the focal length of the seventh lens is defined as f7, the following condition (7) is satisfied. 5.0<f7 / f<20...(7)

8. The imaging lens system according to claim 1, characterized in that it satisfies the following condition (8) when the total optical length of the imaging lens system is defined as TTL. TTL / f<6.0...(8)

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

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

11. The imaging lens system according to claim 1, characterized in that it satisfies the following condition (9) when the design wavelength of the imaging lens system is defined as WL. 800nm<WL<1000nm...(9)

12. The imaging lens system according to claim 1, characterized in that it satisfies the following condition (10) when the half-angle of view of the imaging lens system is defined as ω. ω>80°...(10)

13. A camera module comprising an imaging lens system according to any one of claims 1 to 12, and an image sensor that converts light focused through the imaging lens system into an electrical signal.

14. An in-vehicle system installed in a vehicle, The camera module according to claim 13, 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.

15. A mobile body equipped with the vehicle-mounted system described in claim 14, 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.

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