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

Abstract

Provided are a high-resolution imaging lens system, a camera module, an in-vehicle system, and a moving body. 【Solution means】In the imaging lens system 11, in order from the object side toward the image side, there are arranged a first lens L1 having a negative power with the object side surface facing a convex surface toward the object side, a second lens L2 having a negative power with the object side surface facing a concave surface toward the object side, a third lens L3 having a positive power with the object side surface facing a convex surface toward the object side, and a fourth lens L4. An aperture STOP is arranged between the second lens L2 and the fourth lens L4. The object side surface of the first lens L1 has an aspherical shape. Let the on-axis radius of curvature of the object side surface of the first lens L1 be R0, the maximum value of the radius of curvature be R max , and the radius at which the radius of curvature becomes the maximum value R max be h Rmax , and the effective diameter be h max . When defined as such, the imaging lens system 11 satisfies the following conditional expressions (1) and (2). 1.4 < R max / R0 < 1.7 ···(1) 0.6 < h Rmax / h max < 0.95 ···(2)

Description

[Technical Field]

[0001] This invention relates to imaging lens systems, camera modules, in-vehicle systems, and mobile devices. [Background technology]

[0002] In recent years, in-vehicle cameras have increasingly required sensing capabilities to detect people and objects, leading to higher resolution and larger image sensors. Consequently, the imaging lens systems used in in-vehicle cameras and similar devices are also required to have higher resolution. Patent Document 1 describes a lens system consisting of six lenses that is mounted on an in-vehicle camera or the like. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 2021-516793 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, in the imaging lens system described in Patent Document 1, the first lens is an aspherical lens and has an inflection point on the side surface of the object. Therefore, there is a problem that the coma aberration generated in the first lens tends to increase due to the eccentricity of the first lens during the assembly of the imaging lens system. In addition, because the power of the third lens is large, there is a problem that the coma aberration generated in the first lens tends to increase due to the eccentricity of the third lens during the assembly of the imaging lens system. Consequently, Patent Document 1 may not be able to realize an imaging lens system with sufficiently high resolution.

[0005] This invention has been made in view of these problems, and aims to provide a high-resolution imaging lens system, camera module, in-vehicle system, and mobile device. [Means for solving the problem]

[0006] In an imaging lens system according to an embodiment, a first lens having a negative power with the object-side surface convex toward the object side, a second lens having a negative power with the object-side surface concave toward the object side, a third lens having a positive power with the object-side surface convex toward the object side, and a fourth lens are arranged in order from the object side toward the image side. An aperture is arranged between the second lens and the fourth lens. The object-side surface of the first lens has an aspherical shape. Let the radius of curvature on the optical axis of the object-side surface of the first lens be R0, the maximum value of the radius of curvature of the object-side surface of the first lens be R , , , , , [Figure 1] , ,

[0008] , , ,

[0007] , max , [Figure 4] , [Figure 3] , , [Figure 2] , , , When the radius at which the radius of curvature of the object-side surface of the first lens becomes the maximum value R max is h Rmax and the effective diameter of the object-side surface of the first lens is h max When defined as, the imaging lens system satisfies the following conditional expressions (1) and (2). 1.4 < R max / R0 < 1.7 ···(1) 0.6 < h Rmax / h max <0.95 ···(2)

Advantages of the Invention

[0007] According to the present invention, a high-resolution imaging lens system, a camera module, an in-vehicle system, and a mobile body can be provided.

Brief Description of the Drawings

[0008] [Figure 1] It is a cross-sectional view showing the configuration of the camera module and the imaging lens system according to Example 1. [Figure 2] It is a spherical aberration diagram (longitudinal aberration diagram), a field curvature diagram, and a distortion aberration diagram in the imaging lens system of Example 1. [Figure 3] It is a cross-sectional view showing the configuration of the camera module and the imaging lens system according to Example 2. [Figure 4] It is a spherical aberration diagram (longitudinal aberration diagram), a field curvature diagram, and a distortion aberration diagram in 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 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, and distortion aberration diagram for the imaging lens system of Example 4. [Figure 9] This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 5. [Figure 10] These are the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, and distortion aberration diagram for the imaging lens system of Example 5. [Figure 11] 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 12] Figure 11 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) In the imaging lens system according to Embodiment 1, in order from the object side toward the image side, a first lens having a negative power with the object-side surface facing convex toward the object side, a second lens having a negative power with the object-side surface facing concave toward the object side, a third lens having a positive power with the object-side surface facing convex toward the object side, and a fourth lens are arranged, and an aperture is arranged between the second lens and the fourth lens. The object-side surface of the first lens has an aspherical shape. Let the on-axis curvature radius of the object-side surface of the first lens be R0, the maximum value of the curvature radius of the object-side surface of the first lens be R max , and the radius at which the curvature radius of the object-side surface of the first lens becomes the maximum value R max be h Rmax , and when the effective diameter (also referred to as "effective radius") of the object-side surface of the first lens is defined as h max , the imaging lens system satisfies the following conditional expressions (1) and (2). 1.4 < R max / R0 < 1.7 ···(1) 0.6 < h Rmax / h max <0.95 ···(2) Here, the position (coordinate) in the radial direction of the lens to be noted is h i , the position (coordinate) closer to the center side of the lens than the position h i be h1, the position (coordinate) closer to the peripheral side of the lens than the position h i be h2, when the sag amount at the position h1 is defined as Z1 and the sag amount at the position h2 is defined as Z2, the curvature radius R i at the position h i satisfies Z1 - Z2 = (R i i i 2 2 1 / 2 - h'1 i ) 2 - (R 2 1 / 2 - h'2 max ) max .

[0010] Thereby, a high-resolution imaging-d lens system can be provided. Specifically, by satisfying the above conditions (1) and (2) in the imaging lens system, the increase in coma aberration due to the polarization of the first lens can be suppressed, as can the increase in coma aberration due to the polarization of the third lens. This makes it possible to realize a high-resolution imaging lens system. More specifically, R max If the value of / R0 is 1.4 or less, the curvature of the peripheral side of the object surface of the first lens becomes too sharp, the coma aberration occurring in the first lens becomes too large, and even slight deviation of the third lens becomes unacceptable. On the other hand, R max If the value of / R0 is 1.7 or greater, the curvature of the peripheral part of the object side of the first lens becomes too gentle, and coma aberration is more likely to increase due to the eccentricity of the first lens, so even slight eccentricity of the first lens becomes unacceptable. Also, h Rmax / h max If the value of is 0.6 or less, the point where the curvature of the object side of the first lens is gentlest becomes too close to the center of the lens, and coma aberration tends to increase in the peripheral part of the image plane due to slight deviation of the first lens or slight deviation of the third lens. On the other hand, h Rmax / h max If the value of R is 0.95 or greater, the point where the curvature of the object side of the first lens is gentlest becomes too close to the edge of the lens, and coma aberration is more likely to increase in the range from the center to the periphery of the image plane due to slight deviation of the first lens or the third lens. max The lower limit of / R0 is more preferably 1.45, and even more preferably 1.50. max The upper limit of / R0 is more preferably 1.65, and even more preferably 1.60. Rmax / h max The lower limit of h is more preferably 0.65, 0.70, and even more preferably 0.75. Rmax / h max The upper limit is more preferably 0.90, 0.85, and even more preferably 0.80. Therefore, by satisfying the above conditions (1) and (2), the imaging lens system can provide a high-resolution imaging lens system.

[0011] Furthermore, the first, second, third, fourth, and fifth lenses are arranged in order from the object side towards the image side. When the fourth lens has positive power and the fifth lens has negative power, and the Abbe number for the d line of the fourth lens is defined as νd4 and the Abbe number for the d line of the fifth lens is defined as νd5, it is preferable that the following conditions (3) and (4) are satisfied and the image side of the fourth lens and the object side of the fifth lens are joined. νd4>50 ···(3) νd5<30 ···(4) By joining a fourth lens having positive power that satisfies the above condition (3) and a fifth lens having negative power that satisfies the above condition (4), the dispersion can be balanced between the fourth and fifth lenses, and axial chromatic aberration can be corrected. Furthermore, by joining the image side of the fourth lens and the object side of the fifth lens, the loss of light due to reflections on these surfaces can be suppressed. The lower limit of νd4 is more preferably 51, 52, 53, and even more preferably 54. The upper limit of νd5 is more preferably 29, 28, 27, 26, and even more preferably 25.

[0012] Furthermore, the first, second, third, fourth, fifth, and sixth lenses are arranged in order from the object side towards the image side. Preferably, the fourth lens has positive power, the fifth lens has negative power, and the sixth lens has positive power. Because the sixth lens possesses positive power, it can be assigned a portion of the overall positive power of the imaging lens system, thereby reducing the amount of positive power assigned to the third lens. This suppresses the increase in coma aberration of the first lens caused by the polarization of the third lens.

[0013] Furthermore, it is preferable that the object side and image side of the sixth lens have an aspherical shape. By having aspherical shapes on the object side and image side of the sixth lens, various aberrations can be corrected, enabling the realization of an imaging lens system with excellent imaging performance.

[0014] Furthermore, among the lenses positioned on the image side of the aperture, it is preferable that the image-side surface of the lens positioned closest to the image face toward the image. This allows light rays to be emitted off-axis from the image side of the lens closest to the image among the lenses positioned on the image side of the aperture, making the effective image circle diameter sufficiently large compared to the optical length of the imaging lens system. The optical length is the distance along the optical axis from the object side of the first lens of the imaging lens system to the image plane. The effective image circle diameter is the diameter of the circular image (effective image circle) formed by the imaging lens system, which ensures the required optical performance.

[0015] Furthermore, among the lenses positioned on the image side of the aperture, it is preferable that the object side and image side of the lens positioned closest to the image have an aspherical shape. This allows for the correction of various aberrations, enabling the realization of an imaging lens system with excellent imaging performance.

[0016] (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 high-resolution camera module.

[0017] 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).

[0018] 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.

[0019] The imaging lens system 11 according to Example 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, and a sixth lens L6. The imaging 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.

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

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

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

[0023] 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.

[0024] The fourth lens L4 has positive power. The object side S7 of the fourth lens L4 has a spherical shape with the convex side facing the object. Also, the image side S8 of the fourth lens L4 has a spherical shape with the convex side facing the image.

[0025] The fifth lens L5 has negative power. The object side S9 of the fifth lens L5 has a spherical shape with the concave side facing the object. Also, the image side S10 of the fifth lens L5 has a spherical shape with the concave side facing the image.

[0026] The fourth lens L4 and the fifth lens L5 constitute a cemented lens. That is, the image side S9 of the fourth lens L4 and the object side S10 of the fifth lens L5 are in contact. The fourth lens L4 and the fifth lens L5 are joined by an adhesive layer with an axial thickness of 0.005 mm.

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

[0028] 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 sixth lens L6 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.

[0029] 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, and the Abbe number νd for the d line. In Table 1, surfaces marked with an asterisk (*) are aspherical. The imaging lens system 11 of Example 1 has an F-number of 1.6 and a total field of view of 82°.

[0030] [Table 1]

[0031] 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

[0032] 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, "-1.00980E-03" is equivalent to "-1.00980×10 -3 This means "[...]." The numerical representation is the same for the following table.

[0033] [Table 2]

[0034] 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 height of the light ray's passage over the entrance pupil. Figure 2(A) also shows the simulation results for light rays with wavelengths of 455 nm, 522 nm, 546 nm, 558 nm, 614 nm, and 661 nm. 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 light rays with wavelengths of 455 nm, 522 nm, 546 nm, 558 nm, 614 nm, and 661 nm. 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 light with a wavelength of 550 nm.

[0035] (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.

[0036] 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 1.6 and a total field of view of 82°.

[0037] [Table 3]

[0038] 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.

[0039] [Table 4]

[0040] 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.

[0041] (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.

[0042] 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 1.6 and a total field of view of 82°.

[0043] [Table 5]

[0044] 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.

[0045] [Table 6]

[0046] 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. The explanation of each aberration diagram shown in Figure 6 is the same as in Figure 2, so the explanation is omitted.

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

[0048] 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 1.6 and a total field of view of 82°.

[0049] [Table 7]

[0050] 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.

[0051] [Table 8]

[0052] Figure 8 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, and distortion 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.

[0053] (Example 5) Figure 9 is a cross-sectional view showing the camera module 10 according to Embodiment 5. In the imaging lens system 11 according to Embodiment 5, the aperture stop is positioned between the second lens L2 and the third lens L3. The configuration of the imaging lens system 11 according to Embodiment 5, other than the aperture stop, 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 5 will be described below.

[0054] Table 9 shows the lens data for each lens surface of the imaging lens system 11 according to Example 5. The items in Table 9 are the same as those in Table 1, so their explanations are omitted. In addition, the imaging lens system 11 of Example 5 has an F-number of 1.6 and a total field of view of 82°.

[0055] [Table 9]

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

[0057] [Table 10]

[0058] Figure 10 shows the spherical aberration diagram (longitudinal aberration diagram), field curvature diagram, and distortion aberration diagram for the imaging lens system 11 of Example 5. The explanation of each aberration diagram shown in Figure 10 is the same as in Figure 2, so the explanation is omitted.

[0059] Table 11 shows the focal length f of the entire optical system of the imaging lens system 11, the focal length f1 of the first lens L1, the focal length f2 of the second lens L2, the focal length f3 of the third lens L3, the focal length f4 of the fourth lens L4, the focal length f5 of the fifth lens L5, the focal length f6 of the sixth lens L6, the focal length f7 of the seventh lens L7, the total optical length TTL, R max / R0 value, h Rmax / h max The values ​​of the νd4, Abbe number νd4 of the fourth lens L4, Abbe number νd5 of the fifth lens L5, and effective image circle diameter / optical length (De / TLL) are shown. In Table 11, the units for optical length and focal length are mm. The focal lengths shown in Table 11 were calculated using the e line.

[0060] [Table 11]

[0061] In Examples 1 to 5, by satisfying the above-mentioned conditions (1) and (2), the imaging lens system 11 can suppress the increase in coma aberration of the first lens L1 due to the eccentricity of the first lens L1 or the third lens L3 during the assembly of the imaging lens system 11. This makes it possible to realize an imaging lens system 11 with high resolution. In fact, in Examples 1 to 5, as shown in Figures 2, 4, 6, 8, and 10, various aberrations can be suitably reduced, and in Examples 1 to 5, the imaging lens system 11 has high resolution. Furthermore, in Examples 1 to 5, the F value is 1.6, and the imaging lens system 11 has sufficient brightness for vehicle sensing.

[0062] Furthermore, in Examples 1 to 5, axial chromatic aberration can be corrected by forming a cemented lens with a fourth lens L4 having positive power that satisfies the above condition (3) and a fifth lens L5 having negative power that satisfies the above condition (4). In addition, light loss due to reflection can be suppressed at the cemented surface between the image side of the fourth lens and the object side of the fifth lens.

[0063] Furthermore, in Examples 1 to 5, the sixth lens L6 has positive power, which allows the sixth lens L6 to share the positive power of the entire imaging lens system 11, thereby reducing the amount of positive power that the third lens L3 needs to share. As a result, the increase in coma aberration of the first lens L1 due to the eccentricity of the third lens L3 can be suppressed. In fact, in Examples 1 to 5, as shown in Figures 2, 4, 6, 8, and 10, various aberrations can be suitably reduced.

[0064] Furthermore, in Examples 1 to 5, the object side surface S12 and image side surface S13 of the sixth lens L6 have an aspherical shape, which allows for the correction of various aberrations and enables the realization of an imaging lens system 11 with good imaging performance. In fact, in Examples 1 to 5, as shown in Figures 2, 4, 6, 8, and 10, various aberrations can be suitably reduced.

[0065] Furthermore, in Examples 1-3 and 5, the image side surface S13 of the sixth lens L6 faces the image side, and in Example 4, the image side surface S15 of the seventh lens L7 faces the image side. As shown in Table 11, the effective image circle diameter De can be made sufficiently large compared to the total optical length TTL of the imaging lens system 11.

[0066] Furthermore, in Example 4, the object side surface S14 and image side surface S15 of the seventh lens L7 have an aspherical shape, which allows for correction of various aberrations and enables the realization of an imaging lens system 11 with good imaging performance. In fact, in Examples 1 to 5, as shown in Figures 2, 4, 6, 8, and 10, various aberrations can be suitably reduced.

[0067] Furthermore, by providing the camera module 10 with an imaging lens system 11, a high-resolution camera module 10 can be provided.

[0068] (Embodiment 3) Figure 11 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 the system into an electrical signal. As shown in the figure, the imaging device 50 can be mounted on the vehicle 40, and Figure 11 is an example of an arrangement illustrating the mounting position of the imaging device 50 on the vehicle 40. The imaging device 50 mounted on the vehicle 40 can also be called an in-vehicle camera and can be installed in various locations on the vehicle 40. For example, the first imaging device 50a may be 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.

[0069] 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.

[0070] Figure 12 shows the configuration of the imaging device 50 that constitutes the in-vehicle system shown in Figure 11. 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.

[0071] The control unit 52 controls the camera module 10 and processes the electrical signals output from the image sensor 12 of the camera module 10. 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.

[0072] The storage unit 54 stores various information or parameters related to the operation of the imaging device 50. The storage unit 54 may be 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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]

[0077] 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. From the object side toward the image side, in order, a first lens having negative power with its object side facing convex toward the object side, a second lens having negative power with its object side facing concave toward the object side, a third lens having positive power with its object side facing convex toward the object side, and a fourth lens are arranged, with an aperture positioned between the second lens and the fourth lens. The object side surface of the first lens has an aspherical shape. The radius of curvature of the object side of the first lens on the axis is R. ０ The maximum value of the radius of curvature of the object side surface of the first lens is R ｍａｘ The radius of curvature of the object side surface of the first lens is the maximum value R. ｍａｘ The radius h Ｒｍａｘ The effective diameter of the object side of the first lens is h ｍａｘ When defined as such, it is characterized by satisfying the following conditions (1) and (2): Imaging lens system. 1.4<R ｍａｘ / R ０ <1.7 ・・・(1) 0.6<h Ｒｍａｘ / h ｍａｘ <0.95 ・・・(2)

2. The first lens, second lens, third lens, fourth lens, and fifth lens are arranged in order from the object side toward the image side. The imaging lens system according to claim 1, characterized in that the fourth lens has positive power, the fifth lens has negative power, and when the Abbe number of the fourth lens with respect to the d line is defined as νd4 and the Abbe number of the fifth lens with respect to the d line is defined as νd5, the following conditions (3) and (4) are satisfied, and the image side of the fourth lens and the object side of the fifth lens are joined. νd4>50...(3) νd5<30...(4)

3. The first lens, second lens, third lens, fourth lens, fifth lens, and sixth lens are arranged in order from the object side toward the image side. The fourth lens has positive power, the fifth lens has negative power, and the sixth lens has positive power. The imaging lens system according to claim 1.

4. The first lens, second lens, third lens, fourth lens, fifth lens, and sixth lens are arranged in order from the object side toward the image side. The object side and image side of the sixth lens are characterized by having an aspherical shape. The imaging lens system according to claim 1.

5. The imaging lens system according to claim 1, characterized in that, among the lenses positioned on the image side of the aperture, the image side of the lens positioned closest to the image is concave toward the image side.

6. The imaging lens system according to claim 1, characterized in that, among the lenses arranged on the image side of the aperture, the object side and image side of the lens positioned closest to the image have an aspherical shape.

7. A camera module comprising an imaging lens system according to any one of claims 1 to 6, and an image sensor that converts light focused through the imaging lens system into an electrical signal.

8. An in-vehicle system installed in a vehicle, The camera module according to claim 7, 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.

9. A mobile body equipped with the vehicle-mounted system described in claim 8, 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