Imaging lens system, camera module, vehicle-mounted system, and moving object

Abstract

The invention provides a bright and inexpensive imaging lens system, a camera module, an in-vehicle system, and a moving object which can realize high resolution in a wide range of wavelength bands from visible light to near-infrared light. The camera lens system sequentially comprises a first lens (L1), a second lens (L2), a third lens (L3), a diaphragm (STOP), a fourth lens (L4), a fifth lens (L5) and a sixth lens (L6) from an object side to an image side, the first lens has negative focal power, the concave surface of the image side surface of the first lens faces the image side, the second lens has negative focal power, the concave surface of the image side surface of the second lens faces the image side, the third lens has positive focal power, the diaphragm (STOP) is arranged between the fourth lens (L4) and the fifth lens (L5), and the sixth lens (L6) is arranged between the fourth lens (L4) and the fifth lens (L5). The convex surface of the object side surface of the fourth lens faces the object side, the convex surface of the image side surface of the fourth lens faces the image side, the fifth lens (L5) and the sixth lens (L6) form a bonding lens, one of the fifth lens (L5) and the sixth lens (L6) has negative focal power, the other of the fifth lens (L5) and the sixth lens (L6) has positive focal power, and when the focal lengths of the fourth lens (L4) and the whole optical system are defined as f4 and f respectively, and the Abbe number of d light of the fourth lens (L4) is defined as vd4, the vd4 is larger than the f4. Conditional expressions (1) to (2) are satisfied.

Description

Technical Field

[0001] The invention relates to a camera lens system, a camera assembly, a vehicle-mounted system and a mobile object. Background Art

[0002] In recent years, vehicle-mounted cameras and surveillance cameras installed in vehicles have been required to realize sensing functions that can detect people and objects not only during the day but also at night. Therefore, a high-resolution and inexpensive imaging lens system that is bright with a small F value and can suppress various aberrations in a wide range of wavelengths from visible light to near infrared is required.

[0003] Patent Document 1 discloses an imaging lens system that can be mounted on a vehicle-mounted camera or the like, which is composed of six lenses and can support wavelengths from visible light to infrared light.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-107892 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] However, the imaging lens system described in Patent Document 1 has problems in that the brightness is not high enough because the F value is 2.5, and the imaging lens system is relatively expensive because five glass lenses are used.

[0009] The present invention has been made in view of such problems, and an object of the present invention is to provide an imaging lens system, a camera unit, an in-vehicle system, and a mobile object that achieve high resolution and brightness in a wide wavelength range from visible light to near infrared and are inexpensive.

[0010] Technical means of solving problems

[0011] In an embodiment of the imaging lens system, the imaging lens system includes, from the object side to the image side, a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, and a sixth lens, wherein the first lens has negative power, and its image side surface has a concave surface facing the image side, the second lens has negative power, and its image side surface has a concave surface facing the image side, the third lens has positive power, and its object side surface has a convex surface facing the object side, the fourth lens has positive power, and its image side surface has a convex surface facing the image side, the fifth lens and the sixth lens constitute a cemented lens, one of which has negative power and the other has positive power,

[0012] When the focal length of the fourth lens is defined as f4, the focal length of the entire optical system is defined as f, and the Abbe number of the d-light of the fourth lens is defined as νd4, the following conditional expressions (1) to (2) are satisfied:

[0013] 2.3 <f4 / f<3.9……(1),

[0014] νd4>55……(2).

[0015] Effects of the Invention

[0016] According to the present invention, it is possible to provide an imaging lens system, a camera unit, an in-vehicle system, and a mobile object that realize high resolution and brightness in a wide wavelength range from visible light to near infrared and are inexpensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a cross-sectional view showing the structure of the camera module and the imaging lens system of Example 1.

[0018] Figure 2A This is a spherical aberration diagram (longitudinal aberration diagram) in the imaging lens system of Example 1.

[0019] Figure 2B This is a diagram of field curvature in the imaging lens system of Example 1.

[0020] Figure 2C 1 and 2 are diagrams showing distortion in the imaging lens system of Example 1.

[0021] Figure 2D 1 is a diagram showing chromatic aberration of magnification in the imaging lens system of Example 1.

[0022] Figure 3 It is a cross-sectional view showing the structure of a camera module and an imaging lens system according to Example 2.

[0023] Figure 4A This is a spherical aberration diagram (longitudinal aberration diagram) in the imaging lens system of Example 2.

[0024] Figure 4B This is a diagram of field curvature in the imaging lens system of Example 2.

[0025] Figure 4C This is a distortion diagram in the imaging lens system of Example 2.

[0026] Figure 4D This is a diagram showing chromatic aberration of magnification in the imaging lens system of Example 2.

[0027] Figure 5 It is a cross-sectional view showing the structure of a camera module and an imaging lens system according to Example 3.

[0028] Fig. 6A This is a spherical aberration diagram (longitudinal aberration diagram) in the imaging lens system of Example 3.

[0029] Figure 6BThis is a diagram of field curvature in the imaging lens system of Example 3.

[0030] Figure 6C This is a distortion diagram of the imaging lens system of Example 3.

[0031] Fig.6D This is a diagram showing chromatic aberration of magnification in the imaging lens system of Example 3.

[0032] Figure 7 It is a cross-sectional view showing the structure of a camera module and an imaging lens system according to Example 4.

[0033] Fig. 8A This is a spherical aberration diagram (longitudinal aberration diagram) in the imaging lens system of Example 4.

[0034] Figure 8B This is a diagram of field curvature in the imaging lens system of Example 4.

[0035] Figure 8C This is a distortion diagram in the imaging lens system of Example 4.

[0036] Fig.8D This is a diagram showing chromatic aberration of magnification in the imaging lens system of Example 4.

[0037] Fig. 9 This is a schematic diagram of a vehicle in which an in-vehicle system is equipped with a camera unit according to an embodiment of the present invention.

[0038] Fig.10 It means composition Fig. 9 A block diagram of the structure of the camera device of the vehicle-mounted system. DETAILED DESCRIPTION

[0039] The following describes an embodiment of the present invention with reference to the accompanying drawings. This embodiment is particularly directed to a sensor system that can achieve a high reliability system, which helps to develop disaster-resistant infrastructure, with the goal of "9.1 Develop high-quality, reliable, sustainable and resilient infrastructure, including regional and cross-border infrastructure, to support economic development and enhance human well-being, with a focus on affordable and equitable access to such infrastructure for all." of "9. Industry, Innovation and Infrastructure" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0040] (Embodiment 1: Imaging Lens System)

[0041] The imaging lens system of embodiment 1 includes, from the object side to the image side, a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, and a sixth lens, wherein the first lens has negative power, and its image side surface has a concave surface facing the image side, the second lens has negative power, and its image side surface has a concave surface facing the image side, the third lens has positive power, and its object side surface has a convex surface facing the object side, the fourth lens has positive power, and its image side surface has a convex surface facing the image side, the fifth lens and the sixth lens constitute a cemented lens, one of which has negative power and the other has positive power,

[0042] When the focal length of the fourth lens is defined as f4, the focal length of the entire optical system is defined as f, and the Abbe number of the d-light of the fourth lens is defined as νd4, the following conditional expressions (1) and (2) are satisfied:

[0043] 2.3 <f4 / f<3.9……(1),

[0044] νd4>55……(2).

[0045] This makes it possible to provide an inexpensive imaging lens system that achieves high resolution and brightness over a wide wavelength range from visible light to near infrared.

[0046] Specifically, an aperture is arranged between the third lens and the fourth lens, and since the front group is composed of three lenses, six lens surfaces can be used for aberration correction. Therefore, even if the F value is reduced to form a bright imaging lens system, the aberration caused by the reduced F value can be fully corrected using six lens surfaces. Thus, a sufficiently small F value, bright, and high-resolution imaging lens system can be realized.

[0047] In addition, since the optical power of the fourth lens is within the specified range satisfying conditional expression (1), it is possible to provide an imaging lens system that reduces the focus shift caused by changes in ambient temperature in a wide range of wavelengths from visible light to near infrared. Specifically, when the value of f4 / f is 3.9 or more, the optical power of the fourth lens is too weak and cannot fully correct the axial chromatic aberration, resulting in a large MTF focus shift in the near infrared range. On the other hand, when f4 / f is 2.3 or less, the optical power of the fourth lens is too strong and the axial chromatic aberration is excessively corrected, resulting in a large MTF focus shift in the near infrared range. The value of f4 / f is more preferably 2.5 or more and 3.70 or less, and more preferably 2.8 or more and 3.20 or less.

[0048] In addition, since the Abbe number νd4 of the fourth lens satisfies conditional expression (2), the chromatic aberration of magnification generated in the first lens can be corrected, and high resolution can be achieved. Specifically, when the Abbe number νd4 of the fourth lens is less than 55, the dispersion of the fourth lens is large, and it is difficult to correct axial chromatic aberration and chromatic aberration of magnification. The Abbe number νd4 of the fourth lens is more preferably greater than 60, and further preferably greater than 75.

[0049] This makes it possible to provide an inexpensive imaging lens system that achieves high resolution and brightness over a wide wavelength range from visible light to near infrared.

[0050] In the imaging lens system, when the temperature coefficient of the relative refractive index of d-light of the fourth lens is defined as dNd4 / dt, the following conditional expression (3) is preferably satisfied in the range of 20° C. to 40° C.:

[0051] dNd4 / dt(×10 -6 / ℃)<4.5……(3).

[0052] By satisfying the above-mentioned conditional formula (3), the focus shift of the entire imaging lens system caused by changes in ambient temperature can be suppressed in a wide range of wavelengths from visible light to near infrared. Specifically, the change in the distance from the object side lens surface of the first lens to the imaging surface of the imaging element caused by the expansion and contraction of the lens barrel in the optical axis direction due to changes in ambient temperature (focus shift) can be offset by the focus shift caused by changes in the temperature of the fourth lens itself. In particular, in an imaging lens system for vehicle-mounted use, when the temperature is high, the lens barrel is elongated in the optical axis direction, so that the imaging surface of the imaging element is away from the imaging lens system, but when the temperature of the fourth lens becomes high, the focus of the fourth lens will shift to the image side, thereby maintaining the imaging performance of the imaging lens system.

[0053] In addition, it is preferable that the first lens and the fourth lens are glass lenses, and the second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses.

[0054] By using a glass lens as the first lens, it is possible to provide an imaging lens system that is not easily damaged and has excellent weather resistance against oil stains.

[0055] In addition, by using a glass lens as the fourth lens, it is easy to use a glass material that satisfies Conditional Expression (3) for the fourth lens.

[0056] On the other hand, by using plastic lenses as the second lens, the third lens, the fifth lens, and the sixth lens, the manufacturing cost can be reduced.

[0057] In addition, preferably, in the imaging lens system, when the combined focal length of the fifth lens and the sixth lens is defined as f56 and the focal length of the entire optical system is defined as f, the following conditional expression (4) is satisfied:

[0058] 4.3 <f56 / f<6.0……(4)。

[0059] By satisfying the above conditional expression (6), chromatic aberration of magnification can be properly corrected. Specifically, when the value of f56 / f is 6.0 or more, the focal length of the cemented lens is too weak, the chromatic aberration of magnification cannot be fully corrected, and the resolution performance of the imaging lens system will deteriorate. On the other hand, when the value of f56 / f is 4.3 or less, the focal length of the cemented lens is too strong, the correction of chromatic aberration of magnification is excessive, and the resolution performance of the imaging lens system will deteriorate. The value of f56 / f is more preferably 4.5 or more and 5.8 or less, and more preferably 4.8 or more and 5.6 or less.

[0060] In addition, it is preferable that when the d-light refractive index of the first lens is defined as nd1, the following conditional formula (5) is satisfied:

[0061] nd1>1.9……(5).

[0062] By satisfying the above conditional expression (5), it is possible to achieve both a bright characteristic with an F value of about 2.0 and a wide angle. Specifically, when the value of nd1 is 1.9 or less, the refractive power of the first lens is too weak, making it difficult to achieve both a bright characteristic with an F value of about 2.0 and a wide angle.

[0063] (Implementation 2: Camera assembly)

[0064] The camera assembly of embodiment 2 comprises the above-mentioned imaging lens system and imaging element, wherein the imaging element is arranged at the focal position of the imaging lens system and converts the light focused by the imaging lens system into an electrical signal. Thus, a camera assembly that realizes high resolution, brightness, and low cost in a wide range of wavelengths from visible light to near infrared can be provided.

[0065] Next, examples corresponding to the imaging lens system of Embodiment 1 and the camera module of Embodiment 2 will be described with reference to the drawings.

[0066] (Example 1)

[0067] Figure 1 1 is a cross-sectional view showing the structure of a camera module 10 according to Example 1. Specifically, the camera module 10 includes an imaging lens system 11 and an imaging element 12. The imaging lens system 11 and the imaging element 12 are accommodated in a housing (not shown).

[0068] The imaging element 12 is an element that converts received light into an electric signal, and for example, a CCD image sensor or a CMOS image sensor is used. The imaging element 12 is arranged at an image forming position (focal position) of the imaging lens system 11 .

[0069] The imaging lens system 11 of Example 1 includes, from the object side to the image side, a front group Gf composed of a first lens L1, a second lens L2, and a third lens L3, a stop (STOP), and a rear group Gr composed of a fourth lens L4, a fifth lens L5, and a sixth lens L6. The imaging surface of the imaging lens system 11 is represented by IMG. The first lens L1 and the fourth lens L4 are glass lenses. The second lens L2, the third lens L3, the fifth lens L5, and the sixth lens L6 are plastic lenses.

[0070] In addition, an optical filter (infrared cut filter, visible light / infrared light bandpass filter, etc.) is arranged between the imaging lens system 11 and the imaging element 12 as needed. In this specification, an example in which an infrared cut filter (IRCF) is arranged between the imaging lens system 11 and the imaging element 12 is given for explanation.

[0071] The first lens L1 is a glass lens having negative refractive power. The object-side surface S1 of the first lens L1 has a spherical shape with a convex surface facing the object side. The image-side surface S2 of the first lens L1 has a spherical shape with a concave surface facing the image side.

[0072] The second lens L2 is a plastic lens having negative refractive power. The object side surface S3 of the second lens L2 has an aspherical shape with a convex surface facing the object side. The image side surface S4 of the second lens L2 has an aspherical shape with a concave surface facing the image side.

[0073] The third lens L3 is a plastic lens with positive refractive power. The object side surface S5 of the third lens L3 has an aspherical shape with a convex surface facing the object side. In addition, the image side surface S6 of the third lens L3 has an aspherical shape with a concave surface facing the image side.

[0074] The aperture stop is an aperture that determines the F value (F-number, Fno) of the lens system. The aperture stop is arranged between the third lens L3 and the fourth lens L4.

[0075] The fourth lens L4 is a glass lens having positive refractive power. The object-side surface S9 of the fourth lens L4 has a spherical shape with a convex surface facing the object side. In addition, the image-side surface S10 of the fourth lens L4 has a spherical shape with a convex surface facing the image side.

[0076] The fifth lens L5 is a plastic lens with negative refractive power. The object side surface S11 of the fifth lens L5 has an aspherical shape with a convex surface facing the object side. In addition, the image side surface S12 of the fifth lens L5 has an aspherical shape with a concave surface facing the image side.

[0077] The sixth lens L6 is a plastic lens having positive refractive power. The object-side surface S13 of the sixth lens L6 has an aspherical shape with a convex surface facing the object side. In addition, the image-side surface S14 of the sixth lens L6 has an aspherical shape with a convex surface facing the image side.

[0078] The fifth lens L5 and the sixth lens L6 form a cemented lens. That is, the image side surface S12 of the fifth lens L5 is in contact with the object side surface S13 of the sixth lens L6. The fifth lens L5 and the sixth lens L6 are cemented by a cementing layer with an axial thickness of 0.020 mm.

[0079] The infrared cut filter (IRCF) is a filter for cutting off light in the infrared band. The infrared cut filter is considered to be integrated with the imaging lens system 11 when the imaging lens system 11 is designed. However, the infrared cut filter is not an essential component of the imaging lens system 11. The infrared cut filter is arranged on the image side of the sixth lens L6.

[0080] In addition, a sensor cover glass may be disposed between the infrared cut filter and the imaging element 12 in order to prevent dirt from adhering to the imaging element 12 .

[0081] Table 1 shows lens data of each lens surface in the imaging lens system 11 of Example 1. Table 1 shows the curvature radius (mm) of each surface, the surface spacing (mm) on the central optical axis, the refractive index nd for d-light, and the Abbe number νd for d-light as lens data. ” indicates an aspherical surface.

[0082] [Table 1]

[0083]

[0084] Regarding the aspheric shape used in the lens surface, when z is the sag, c is the inverse of the radius of curvature, k is the cone coefficient, and r is the height of the light from the optical axis OA, the aspheric coefficients of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th orders are α4, α6, α8, α 10 , α 12 , α 14 , α 16 , can be expressed as follows.

[0085]

[0086] Table 2 shows the aspheric coefficients for defining the aspheric shape of the lens surface formed as an aspheric surface in the imaging lens system 11 of Example 1. In Table 2, for example, "-1.387794E-02" means "-1.387794×10 -2 The same applies to the numerical expressions in the following tables.

[0087] [Table 2]

[0088]

[0089] Next, aberrations will be described using the drawings. Figure 2A to Figure 2D Graphs showing spherical aberration (longitudinal aberration), field curvature, distortion, and lateral chromatic aberration in the imaging lens system 11 of Example 1. Figure 2A to Figure 2D As shown, in the imaging lens system 11 of Example 1, the F value is 2.0 and the half angle of view is 107.1°.

[0090] in addition, Figure 2A In the longitudinal aberration diagram, the horizontal axis represents the position where the light intersects the optical axis OA, and the vertical axis represents the passing height of the light on the entrance pupil. Figure 2A Displays simulation results for d light, C light, F light, and IR (near infrared light).

[0091] in addition, Figure 2B In the field curvature diagram, the horizontal axis represents the distance in the direction of the optical axis OA, and the vertical axis represents the image height (field angle). Figure 2B In the field curvature diagram, Sag represents the imaging position of the sagittal beam, and Tan represents the imaging position of the meridional beam. In addition, Figure 2B It shows the simulation result of d light.

[0092] in addition, Figure 2C In the distortion diagram, the horizontal axis represents the image distortion (%), and the vertical axis represents the image height (angle of view). Figure 2C This figure shows the simulation result of the d-light ray.

[0093] in addition, Figure 2D In the magnification chromatic aberration diagram, the horizontal axis represents the magnification chromatic aberration amount, and the vertical axis represents the image height (angle of view). Figure 2D Displays simulation results for d light, C light, F light, and IR (near infrared light).

[0094] (Example 2)

[0095] Figure 3 2 is a cross-sectional view showing a camera unit 10 according to Example 2. The imaging lens system 11 according to Example 2 has the same lens structure as that of Example 1, and thus its description is omitted. The characteristic data of the imaging lens system 11 according to Example 2 will be described below.

[0096] Table 3 shows lens data of each lens surface of the imaging lens system 11 of Example 2. The items shown in Table 3 are the same as those in Table 1, and thus their description is omitted.

[0097] [Table 3]

[0098]

[0099] Table 4 shows the aspheric coefficients for defining the aspheric shape of the lens surface formed as an aspheric surface in the imaging lens system 11 of Example 2. In Table 4, the aspheric shape of the lens surface is expressed using the same formula as that of Example 1.

[0100] [Table 4]

[0101]

[0102] exist Figures 4A to 4D , a spherical aberration diagram (longitudinal aberration diagram), a field curvature diagram, a distortion diagram, and a lateral chromatic aberration diagram in the imaging lens system 11 of Example 2 are shown. Figure 4A to Figure 4D Explanation of each aberration diagram shown Figure 2A to Figure 2D The same, so the description is omitted.

[0103] (Example 3)

[0104] Figure 5 1 is a cross-sectional view showing a camera assembly 10 of Example 3. The imaging lens system 11 of Example 3 has the same lens structure as that of Example 1, except that the object-side surface S11 of the fifth lens L5 has an aspherical shape with the concave surface facing the object side, so the description thereof is omitted. The characteristic data of the imaging lens system 11 of Example 3 will be described below.

[0105] Table 5 shows lens data of each lens surface of the imaging lens system 11 of Example 3. The items shown in Table 5 are the same as those in Table 1, and thus their description is omitted.

[0106] [Table 5]

[0107]

[0108] Table 6 shows the aspheric coefficients for defining the aspheric shape of the lens surface formed as an aspheric surface in the imaging lens system 11 of Example 3. In Table 6, the aspheric shape adopted by the lens surface is expressed using the same formula as that of Example 1.

[0109] [Table 6]

[0110]

[0111] exist Figure 6A to Figure 6D, a spherical aberration diagram (longitudinal aberration diagram), a field curvature diagram, a distortion diagram, and a lateral chromatic aberration diagram in the imaging lens system 11 of Example 3 are shown. Figure 6A to Figure 6D Explanation of each aberration diagram shown Figure 2A to Figure 2D The same, so the description is omitted.

[0112] (Example 4)

[0113] Figure 7 1 is a cross-sectional view showing a camera unit 10 according to Example 4. The imaging lens system 11 according to Example 4 has the same lens structure as that of Example 1, and thus its description is omitted. The characteristic data of the imaging lens system 11 according to Example 4 will be described below.

[0114] Table 7 shows lens data of each lens surface of the imaging lens system 11 of Example 4. The items shown in Table 7 are the same as those in Table 1, and thus their description is omitted.

[0115] [Table 7]

[0116]

[0117] Table 8 shows the aspheric coefficients for defining the aspheric shape of the lens surface formed as an aspheric surface in the imaging lens system 11 of Example 4. In Table 8, the aspheric shape adopted by the lens surface is expressed using the same formula as that of Example 1.

[0118] [Table 8]

[0119]

[0120] exist Figures 8A to 8D , a spherical aberration diagram (longitudinal aberration diagram), a field curvature diagram, a distortion diagram, and a lateral chromatic aberration diagram in the imaging lens system 11 of Example 4 are shown. Figures 8A to 8D Explanation of each aberration diagram shown Figure 2A to Figure 2D The same, so the description is omitted.

[0121] Table 9 shows the F value (F No) of the imaging lens system 11, the full angle of view, the focal length f of the entire optical system of the imaging lens system 11, the value of f4 / f, the Abbe number νd4 of the d-light of the fourth lens, dNd4 / dt (×10 -6 / °C), the value of f56 / f, 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, and the combined focal length f56 of the fifth lens L5 and the sixth lens L6. In Table 9, the units of focal length and total optical length are mm. In Table 9, the unit of field angle is °. In addition, the focal length and total length shown in Table 9 are calculated using light with a wavelength of 550 nm.

[0122] [Table 9]

[0123]

[0124] In Examples 1 to 4, an aperture is arranged between the third lens and the fourth lens. Thus, even if the F value is reduced to make a bright imaging lens system, the aberration caused by the reduced F value can be fully corrected using the 6 lens surfaces of the front group. Thus, an imaging lens system with a sufficiently small F value and thus bright and high resolution can be realized. In fact, in Examples 1 to 4, the F value is 2.0 to 2.05, realizing a sufficiently bright imaging lens system 11. In addition, the imaging lens system 11 of Examples 1 to 4 is as follows: Figure 2A to Figure 2D , Figure 4A to Figure 4D , Figure 6A to Figure 6D , Figures 8A to 8D As shown, spherical aberration, field curvature, distortion aberration, and chromatic aberration of magnification are appropriately reduced, the imaging performance is excellent, and high resolution can be achieved.

[0125] In addition, since the optical power of the fourth lens is within the specified range satisfying conditional expression (1), it is possible to provide an imaging lens system that reduces the focus shift caused by changes in ambient temperature in a wide range of wavelengths from visible light to near infrared. Table 10 shows the focus shift amount (μm) caused by changes in ambient temperature of the focal length f of the imaging lens system 11 of Examples 1 to 4. Table 10 shows the focus shift amount compared to the focal length f at room temperature 25°C. In addition, the material of the lens barrel and the housing used when calculating the focus shift amount of the focal length f shown in Table 10 is RenyXL1027U manufactured by Mitsubishi Engineering-Plastics Corporation.

[0126] [Table 10]

[0127]

[0128] In addition, since the Abbe number νd4 of the fourth lens satisfies the conditional expression (2), the chromatic aberration of magnification generated in the first lens can be corrected, and high resolution can be achieved. Figure 2D , Figure 4D , Fig.6D , Fig.8DAs shown, the chromatic aberration of magnification can be appropriately reduced.

[0129] In Examples 1 to 4, the imaging lens system 11 satisfies the above-mentioned conditional expression (3). Therefore, as shown in Table 10, the focus deviation amount of the entire imaging lens system caused by the change in ambient temperature can be suppressed in a wide wavelength range from visible light to near infrared.

[0130] In Examples 1 to 4, the first lens L1 and the fourth lens L4 are glass lenses, and the second lens L2, the third lens L3, the fifth lens L5, and the sixth lens L6 are plastic lenses. By using a glass lens as the first lens L1, it is possible to provide an imaging lens system 11 with excellent weather resistance. In addition, by using a glass lens as the fourth lens L4, it is possible to provide an imaging lens system 11 in which focus shift caused by changes in ambient temperature is reduced. In addition, by using plastic lenses as the second lens L2, the third lens L3, the fifth lens L5, and the sixth lens L6, it is possible to reduce manufacturing costs.

[0131] In addition, in Examples 1 to 4, the imaging lens system 11 satisfies the above-mentioned conditional expression (4). Thus, the chromatic aberration of magnification can be appropriately corrected. Figure 2D , Figure 4D , Fig.6D , Fig.8D As shown, the chromatic aberration of magnification can be appropriately reduced.

[0132] In addition, in Examples 1 to 4, the imaging lens system 11 satisfies the above-mentioned conditional expression (5). As a result, it is possible to achieve both a bright characteristic with an F value of about 2.0 and a wide angle (achieving both). In fact, in Examples 1 to 4, the F value is 2.0 to 2.05, and a sufficiently bright imaging lens system 11 is realized. In addition, in Examples 1 to 4, the half angle of view ω is 107.1° to 108.8°, and an imaging lens system 11 with a sufficiently large angle of view is realized.

[0133] The camera unit 10 also includes the imaging lens system 11 . Since the imaging lens system 11 is miniaturized and has a resolution sufficient for image recognition in autonomous driving, the camera unit 10 can be miniaturized and highly accurate sensing can be achieved.

[0134] (Implementation method 3)

[0135] Fig. 91 is a schematic diagram of a vehicle 40, and the vehicle-mounted system mounted on the vehicle 40 includes an imaging device 50, and the imaging device 50 includes an imaging lens system 11 of Embodiment 1 or Embodiment 2 and an imaging element 12 that converts light focused by the imaging lens system 11 into an electrical signal. As shown in the figure, the imaging device 50 can be mounted on the vehicle 40, Fig. 9 1 is an example of the configuration of the mounting position of the camera device 50 in the vehicle 40. The camera device 50 mounted in the vehicle 40 can also be called a vehicle-mounted camera, and can be installed in various places in the vehicle 40. For example, the first camera device 50a can be used as a camera to monitor the front of the vehicle 40 when it is traveling, and can be installed in the front bumper or its vicinity. In addition, the second camera device 50b that monitors the front can be installed near the inner rearview mirror (Inner Rearview Mirror) of the vehicle 40. The third camera device 50c can be installed on the instrument panel or in the instrument panel as a camera to monitor the driving status of the driver. The fourth camera device 50d can be installed at the rear of the vehicle 40 to monitor the rear of the vehicle 40. The camera devices 50a and 50b can be called front cameras. The third camera device 50c can be called an internal camera. The fourth camera device 50d can be called a rear camera. The camera device 50 is not limited to this, and includes camera devices installed in various positions, such as a left camera that shoots the left rear side and a right camera that shoots the right rear side.

[0136] The image signal of the image captured by the camera 50 can be output to the information processing device 42 and / or the display device 43 in the vehicle 40. The information processing device 42 and the display device 43 together with the camera 50 constitute an in-vehicle system. The information processing device 42 in the vehicle 40 includes a device that processes the image signal obtained by the camera 50 and recognizes various objects in the above-mentioned camera image to assist the driver in driving. In addition, the information processing device 42 includes, for example, a navigation device, a collision damage reduction braking device, a vehicle distance control device, and a lane departure warning device, but is not limited to this. The display device 43 displays the image processed and output by the information processing device 42, but can also directly receive the image signal from the camera 50. In addition, the display device 43 can adopt a liquid crystal display (LCD: Liquid Crystal Display), an organic EL (Electro-Luminescence) display, and an inorganic EL display, but is not limited to this. The display device 43 can display the image signal output by the camera 50 that captures the image of the position that is difficult for the driver to see from the rear camera, etc., to the driver and other passengers.

[0137] exist Fig.10 In the figure, the composition is shown Fig. 9As shown in the figure, the imaging device 50 of one embodiment includes a control unit 52, a storage unit 54, and a camera unit 10.

[0138] The control unit 52 controls the camera assembly 10 and processes the electrical signal output from the imaging element 12 of the camera assembly 10. The control unit 52 can be configured as a processor, for example. In addition, the control unit 52 can also include one or more processors. The processor can include a general-purpose processor that reads a specific program to perform a specific function, and a dedicated processor dedicated to a specific process. The dedicated processor can include an IC (Integrated Circuit) for a specific purpose. An IC for a specific purpose is also called an ASIC (Application Specific Integrated Circuit). The processor can include a programmable logic device. A programmable logic device is also called a PLD (Programmable Logic Device). The PLD can include an FPGA (Field-Programmable Gate Array). The control unit 52 can be any one of a SoC (System-on-a-Chip) and a SiP (System In a Package) in which one or more processors work together.

[0139] The storage unit 54 stores various information or parameters related to the operation of the imaging device 50. The storage unit 54 can be formed of, for example, a semiconductor memory or the like. The storage unit 54 can function as a working memory of the control unit 52. The storage unit 54 can store the captured images. The storage unit 54 can store various parameters used by the control unit 52 for detection processing based on the captured images. The storage unit 54 can also be included in the control unit 52.

[0140] As described above, the camera unit 10 captures a subject image formed by the imaging lens system 11 using the imaging element 12, and outputs the captured image. The image captured by the camera unit 10 is also referred to as a captured image.

[0141] The imaging element 12 may be formed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device). The imaging element 12 has an imaging surface formed by arranging a plurality of pixels. Each pixel outputs a signal determined based on a current or voltage corresponding to the amount of incident light. The signal output by each pixel is also referred to as imaging data.

[0142] The camera component 10 can read the image data for all pixels and import it into the control unit 52 as a camera image. The camera image read for all pixels is also called the maximum camera image. The camera data can also be read for a part of the pixels through the camera component 10 and imported as a camera image. In other words, the camera data can also be read from the pixels in a specified import range. The camera data read from the pixels in the specified import range can be imported as a camera image. The specified import range can be set by the control unit 52. The camera component 10 can obtain the specified import range from the control unit 52. The imaging element 12 can capture an image of the specified import range in the subject image formed by the imaging lens system 11.

[0143] In addition, the present invention is not limited to the above-mentioned embodiments, and can be appropriately modified within the scope of the present invention. For example, the use of the imaging lens system of the present invention is not limited to vehicle-mounted cameras and surveillance cameras, but can also be used for other purposes such as being mounted on small electronic devices such as mobile phones.

[0144] This application claims priority based on Japanese patent application No. 2022-113781 filed on July 15, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0145] Industrial Applicability

[0146] It is possible to provide an imaging lens system, a camera unit, an in-vehicle system, and a mobile object that achieve high resolution, brightness, and low cost in a wide wavelength range from visible light to near infrared.

[0147] Description of Reference Numerals

[0148] 10 Camera Components

[0149] 11 Camera lens system

[0150] 12 Camera Components

[0151] 40 Vehicles (mobile objects)

[0152] 42 Information processing device (processing device)

[0153] 43 Display device (output device)

[0154] 50Camera device

[0155] 52 Control Department

[0156] L1 first lens

[0157] L2 Second Lens

[0158] L3 third lens

[0159] L4 fourth lens

[0160] L5 fifth lens

[0161] L6 sixth lens

[0162] STOP Aperture

[0163] Gf front group

[0164] Gr group

[0165] IRCF Infrared Cutoff Filter

[0166] IMG imaging surface

[0167] OA optical axis

Claims

1. A camera lens system, characterized in that: The lens system includes, from the object side to the image side, a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, and a sixth lens, wherein the first lens has negative power, and its image side surface makes its concave surface face the image side, the second lens has negative power, and its image side surface makes its concave surface face the image side, the third lens has positive power, and its object side surface makes its convex surface face the object side, the fourth lens has positive power, and its image side surface makes its convex surface face the image side, the fifth lens and the sixth lens constitute a cemented lens, one of which has negative power and the other has positive power, When the focal length of the fourth lens is defined as f4, the focal length of the entire optical system is defined as f, and the Abbe number of the d-light of the fourth lens is defined as νd4, the following conditional expressions (1) to (2) are satisfied: 2.3 <f4 / f<3.9……(1), νd4>55……(2).

2. The imaging lens system according to claim 1, wherein: When the temperature coefficient of the relative refractive index of the d-light of the fourth lens is defined as dNd4 / dt, in the range of 20°C to 40°C, the following conditional formula (3) is satisfied: dNd4 / dt(×10 -6 / ℃)<4.5……(3)。 3. The imaging lens system according to claim 1, wherein: The first lens and the fourth lens are glass lenses, The second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses.

4. The imaging lens system according to claim 2, wherein: The first lens and the fourth lens are glass lenses, The second lens, the third lens, the fifth lens, and the sixth lens are plastic lenses.

5. The imaging lens system according to claim 1, wherein: When the combined focal length of the fifth lens and the sixth lens is defined as f56 and the focal length of the entire optical system is defined as f, the following conditional formula (4) is satisfied: 4.3 <f56 / f<6.0……(4)。 6. The imaging lens system according to claim 2, wherein: When the combined focal length of the fifth lens and the sixth lens is defined as f56 and the focal length of the entire optical system is defined as f, the following conditional formula (4) is satisfied: 4.3 <f56 / f<6.0……(4)。 7. The imaging lens system according to claim 3, wherein: When the combined focal length of the fifth lens and the sixth lens is defined as f56 and the focal length of the entire optical system is defined as f, the following conditional formula (4) is satisfied: 4.3 <f56 / f<6.0……(4)。 8. The imaging lens system according to claim 1, wherein: When the d-light refractive index of the first lens is defined as nd1, the following conditional formula (5) is satisfied: nd1>1.9……(5).

9. The imaging lens system according to claim 2, wherein: When the d-light refractive index of the first lens is defined as nd1, the following conditional formula (5) is satisfied: nd1>1.9……(5).

10. The imaging lens system according to claim 3, wherein: When the d-light refractive index of the first lens is defined as nd1, the following conditional formula (5) is satisfied: nd1>1.9……(5).

11. The imaging lens system according to claim 4, wherein: When the d-light refractive index of the first lens is defined as nd1, the following conditional formula (5) is satisfied: nd1>1.9……(5).

12. A camera assembly, characterized in that: The imaging lens system comprises the imaging lens system according to any one of claims 1 to 11, and an imaging element that converts light focused by the imaging lens system into an electrical signal.

13. A vehicle-mounted system for use in a vehicle, characterized in that: include: The camera assembly as claimed in claim 12; and An information processing device processes a captured image output from the imaging element of the camera unit to recognize an object in the captured image.

14. A mobile object equipped with the vehicle-mounted system according to claim 13, characterized in that: The vehicle-mounted system also includes an output device for outputting information to passengers. The information processing device is configured to be able to output the identification information of the object to the output device.

Images