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 brightness for imaging inside a vehicle. [Solution] The imaging lens system 11 consists of, in order from the object side toward the image side, a first lens L1 having a meniscus shape with the object side surface facing the object side with a concave surface; an aperture diaphragm STOP; a second lens L2 having positive power with the object side surface facing the object side with a convex surface; a third lens L3 having positive power; a fourth lens L4 having a meniscus shape with the object side surface facing the object side with a concave surface and positive power; and a fifth lens L5 having negative power.

Description

Technical Field

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

Background Art

[0002] In recent years, as an in-vehicle sensing camera, the demand for an occupant monitoring camera that monitors the inside of a vehicle has been increasing. In order to image a dark vehicle interior, an in-vehicle sensing camera is required to have a bright imaging optical system. Patent Document 1 describes a lens system of an in-vehicle sensing camera composed of five lenses with an F-number of 4.6 to 4.8 as an in-vehicle imaging lens system.

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 F-number is 4.6 to 4.8, the brightness is insufficient for imaging the inside of a vehicle. Further, since the imaging lens system described in Patent Document 1 is entirely composed of glass lenses, there is a problem that the cost is high.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide an imaging lens system, a camera module, an in-vehicle system, and a moving body having sufficient brightness for imaging the inside of a vehicle. [[ID=​​​​​One embodiment of the imaging lens system comprises, in order from the object side toward the image side, a first lens having a meniscus shape with the object side surface facing the object side with a concave surface; an aperture diaphragm; a second lens having positive power with the object side surface facing the object side with a convex surface; a third lens having positive power; a fourth lens having a meniscus shape with the object side surface facing the object side with a concave surface and positive power; and a fifth lens having negative power. [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 sufficient brightness for imaging inside a vehicle. [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) and the field curvature diagram (astigmatism 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) and the field curvature diagram (astigmatism 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) and the field curvature diagram (astigmatism 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) and the field curvature diagram (astigmatism 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) and the field curvature diagram (astigmatism diagram) for the imaging lens system of Example 5. [Figure 11] This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Embodiment 6. [Figure 12] These are the spherical aberration diagram (longitudinal aberration diagram) and the field curvature diagram (astigmatism diagram) for the imaging lens system of Example 6. [Figure 13] 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 14] Figure 13 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 effective in realizing highly reliable systems in sensing systems and contribute to the development of robust infrastructure. They target "3.6 By 2020, halve the number of road traffic fatalities and injuries worldwide" of the United Nations' Sustainable Development Goals (SDGs). (Embodiment 1: Imaging lens system) The imaging lens system according to Embodiment 1 comprises, in order from the object side toward the image side, a first lens having a meniscus shape with the object side surface facing the object side with a concave surface; an aperture diaphragm; a second lens having positive power with the object side surface facing the object side with a convex surface; a third lens having positive power; a fourth lens having a meniscus shape with the object side surface facing the object side with a concave surface and positive power; and a fifth lens having negative power.

[0010] This makes it possible to provide an imaging lens system that has sufficient brightness for imaging inside a vehicle. Specifically, in order to improve the brightness of the imaging lens system, when the diameter of the aperture stop is enlarged, the spherical aberration increases. However, the spherical aberration that has increased can be corrected by the object-side surface and the image-side surface of the second lens having a positive power with the convex surface facing the object side on the object side, and the object-side surface and the image-side surface of the third lens having a positive power. Therefore, an imaging lens system having sufficient brightness for imaging inside the vehicle can be provided.

[0011] Also, the second lens is preferably a glass lens. By using a glass lens with a relatively small linear expansion coefficient for the second lens, which makes a large contribution to the focal length of the entire imaging lens system, the amount of focus shift due to changes in the environmental temperature can be reduced, and an imaging lens system having good resolution performance can be realized.

[0012] Also, when the focal length of the second lens is defined as F2 and the focal length of the third lens is defined as F3, the imaging lens system preferably satisfies the following conditional expression (1). 0.45 < F2 / F3 < 1.15 ···(1) By satisfying the above condition (1) in the imaging lens system, the amount of focus shift due to changes in ambient temperature can be suitably reduced, and an imaging lens system with good imaging performance can be realized. Specifically, by setting the relationship between the power of the second lens and the third lens, which have a large contribution to the focal length of the entire imaging lens system, within a predetermined range, the amount of focus shift due to changes in ambient temperature can be suitably reduced. More specifically, when the F2 / F3 value is 0.45 or less, the power of the second lens is too strong compared to the third lens, and the contribution of the power change of the third lens when the ambient temperature changes to the power change of the entire optical system becomes small, resulting in insufficient correction of focus shift due to changes in ambient temperature. On the other hand, when the F2 / F3 value is 1.15 or more, the power of the third lens is too strong compared to the second lens, and the contribution of the power change of the third lens when the ambient temperature changes to the power change of the entire optical system becomes large, resulting in excessive correction of focus shift due to changes in ambient temperature. The lower limit of F2 / F3 is more preferably 0.47, and even more preferably 0.49. Furthermore, the upper limit of F3 / F is more preferably 1.13, and even more preferably 1.11.

[0013] Furthermore, it is preferable that the imaging lens system satisfies the following condition (2), when the distance along the optical axis between the image side of the second lens and the object side of the third lens is defined as (L2-L3), and the distance along the optical axis from the object side of the first lens to the image plane of the image sensor is defined as TTL. (L2-L3) / TTL<0.04 ···(2) By satisfying the above condition (2) in the imaging lens system, a large aperture and good resolution performance can be achieved. If the value of (L2-L3) / TTL is 0.04 or greater, the lens spacing between the second and third lenses becomes too large, and the height of peripheral light rays incident from the second lens to the third lens decreases. As a result, it becomes difficult to correct higher-order spherical aberration in the third lens, making it difficult to achieve a large aperture. In addition, by satisfying the above condition (2) in the imaging lens system, the deterioration of optical performance caused by changes in ambient temperature can be suppressed. If the value of (L2-L3) / TTL is 0.04 or greater, the expansion and contraction of the spacer ring placed between the second and third lenses due to changes in ambient temperature becomes too large, making it difficult to suppress the deterioration of optical performance due to fluctuations in the lens spacing. Furthermore, it is preferable that the value of (L2-L3) / TTL is greater than 0.01. If the value of (L2-L3) / TTL is 0.01 or less, it becomes difficult to ensure a lens spacing that prevents physical interference between the second and third lenses during the assembly of the imaging lens system. The upper limit of (L2-L3) / TTL is more preferably 0.03, and even more preferably 0.02.

[0014] Furthermore, it is preferable that the imaging lens system satisfies the following condition (3), when the thickness of the center of the first lens is defined as T1 and the focal length of the entire imaging lens system is defined as F. 0.2 <T1 / F<0.45 ···(3) By satisfying the above condition (3) in the imaging lens system, in other words, by controlling the thickness T1 at the center of the first lens to an appropriate thickness, it is possible to balance maintaining imaging performance with miniaturization. Specifically, if the value of T1 / F is 0.2 or less, the thickness at the center of the first lens is too thin, and the height at which peripheral light rays pass over the image side of the first lens becomes low, making it difficult to correct higher-order spherical aberration in the second lens and making it difficult to increase the aperture. On the other hand, if the value of T1 / F is 0.45 or more, the thickness T1 at the center of the first lens is too thick, and the power of the first lens becomes small, making it difficult to correct field curvature and reducing resolution performance. Also, the optical total length TTL becomes longer and the size increases. The lower limit of T1 / F is more preferably 0.22, and even more preferably 0.25. The upper limit of T1 / F is more preferably 0.43, and even more preferably 0.40.

[0015] (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 sufficient brightness for imaging inside a vehicle.

[0016] 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).

[0017] 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.

[0018] The imaging lens system 11 according to Example 1 consists of, in order from the object side to the image side, a front group Gf consisting of a first lens L1, an aperture diaphragm (STOP), and a rear group Gr consisting of a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. The image plane of the imaging lens system 11 is shown as IMG. The second lens L2 is a glass lens. The first lens L1, the third lens L3, the fourth lens L4, and the fifth lens L5 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.

[0019] 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 concave surface facing the object. The image side S2 of the first lens L1 has an aspherical shape with a convex surface facing the image.

[0020] The aperture stop is the aperture diaphragm that determines the F-number (F-number, Fno) of the lens system. The aperture stop is located between the first lens L1 and the second lens L2.

[0021] The second lens L2 is a positive power lens. The object side S4 of the second lens L2 has a spherical shape with the convex side facing the object. The image side S5 of the second lens L2 has a spherical shape with the concave side facing the image.

[0022] The third lens L3 is a positive power lens. The object side S6 of the third lens L3 has an aspherical shape with a convex surface facing the object. Also, the image side S7 of the third lens L3 has an aspherical shape with a convex surface facing the image. Because the object side S6 and image side S7 of the third lens L3 are aspherical, spherical aberration caused by widening the aperture of the aperture stop can be corrected.

[0023] The fourth lens L4 is a positive-power meniscus lens. The object side S8 of the fourth lens L4 has an aspherical shape with a concave surface facing the object. The image side S9 of the fourth lens L4 has an aspherical shape with a convex surface facing the image.

[0024] The fifth lens L5 is a negative power lens. The object side S10 of the fifth lens L5 has an aspherical shape with a concave surface facing the object. The image side S11 of the fifth lens L5 also has an aspherical shape with a concave surface facing the image.

[0025] 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 fifth lens L5. 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.

[0026] 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 nd for the d line, and the Abbe number νd for the d line. In Table 1, surfaces marked with an asterisk (*) are aspherical. In addition, the imaging lens system 11 of Example 1 has an F-number of 1.80 and a half-angle of view (ω) of 35.0°.

[0027] [Table 1]

[0028] 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

[0029] 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, "-3.54419E-02" is equivalent to "-3.54419×10 -4 This means "[...]." The numerical representation is the same for the following table.

[0030] [Table 2]

[0031] Next, aberrations will be explained using diagrams. Figure 2 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature 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 light rays at 930 nm, 950 nm, and 970 nm. Furthermore, in the astigmatism / field curvature diagram in 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 astigmatism / field curvature diagram in Figure 2(B), Sag shift represents the imaging position in the sagittal beam, and Tan shift represents the imaging position in the tangential beam. Figure 2(B) also shows the simulation results for a 950 nm beam.

[0032] (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.

[0033] 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 1.80 and a half-angle of view (ω) of 35.0°.

[0034] [Table 3]

[0035] 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.

[0036] [Table 4]

[0037] Figure 4 shows the spherical aberration diagram (longitudinal aberration diagram) and field curvature diagram (astigmatism 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.

[0038] (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 has the same lens configuration as in Embodiment 1, so its description will be omitted. The characteristic data of the imaging lens system 11 according to Embodiment 3 will be described below.

[0039] 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 1.8 and a half-angle of view (ω) of 35.0°.

[0040] [Table 5]

[0041] 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.

[0042] [Table 6]

[0043] Figure 6 shows the spherical aberration diagram (longitudinal aberration diagram) and field curvature diagram (astigmatism 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.

[0044] (Example 4) Figure 7 is a cross-sectional view showing the camera module 10 according to Embodiment 4. The configuration of the imaging lens system 11 according to Embodiment 4 has the same lens configuration as in Embodiment 1, so its description will be omitted. The characteristic data of the imaging lens system 11 according to Embodiment 4 will be described below.

[0045] 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 explanation is omitted. In addition, the imaging lens system 11 of Example 4 has an F-number of 1.8 and a half-angle of view (ω) of 35.0°.

[0046] [Table 7]

[0047] 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.

[0048] [Table 8]

[0049] Figure 8 shows the spherical aberration diagram (longitudinal aberration diagram) and field curvature diagram (astigmatism 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.

[0050] (Example 5) Figure 9 is a cross-sectional view showing a camera module 10 according to Embodiment 5. In the imaging lens system 11 according to Embodiment 5, the first lens L1 has positive power, the object side surface S1 has an aspherical shape with a concave surface facing the object side, and the image side surface S2 has an aspherical shape with a convex surface facing the image side. The configuration of the imaging lens system 11 according to Embodiment 5, other than the first lens L1, has the same lens configuration as in Embodiment 1, so its description is omitted. The characteristic data of the imaging lens system 11 according to Embodiment 5 will be described below.

[0051] Table 9 shows the lens data for each lens surface of the imaging lens system 11 according to Example 5. The items shown in Table 9 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 5 has an F-number of 1.8 and a half-angle of view (ω) of 35.0°.

[0052] [Table 9]

[0053] 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.

[0054] [Table 10]

[0055] Figure 10 shows the spherical aberration diagram (longitudinal aberration diagram) and field curvature diagram (astigmatism 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.

[0056] (Example 6) Figure 11 is a cross-sectional view showing a camera module 10 according to Embodiment 6. In the imaging lens system 11 according to Embodiment 6, the second lens L2 has positive power, the object side surface S4 has a spherical shape with a convex surface facing the object side, and the image side surface S5 has a spherical shape with a convex surface facing the image side. The configuration of the imaging lens system 11 according to Embodiment 6, other than the second lens L2, has the same lens configuration as in Embodiment 1, so its description is omitted. The characteristic data of the imaging lens system 11 according to Embodiment 6 will be described below.

[0057] Table 11 shows the lens data for each lens surface of the imaging lens system 11 according to Example 6. The items shown in Table 11 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 6 has an F-number of 1.8 and a half-angle of view (ω) of 35.0°.

[0058] [Table 11]

[0059] Table 12 shows the aspheric coefficients used to define the aspheric shape of the lens surface in the imaging lens system 11 of Example 6. In Table 12, the aspheric shape adopted for the lens surface is expressed by the same formula as in Example 1.

[0060] [Table 12]

[0061] Figure 12 shows the spherical aberration diagram (longitudinal aberration diagram) and field curvature diagram (astigmatism diagram) for the imaging lens system 11 of Example 6. The explanation of each aberration diagram shown in Figure 12 is the same as in Figure 2, so the explanation is omitted.

[0062] Table 13 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, TTL value, F2 / F3 value, (L2-L3) / TTL value, and T1 / F value of the imaging lens system 11. In Table 13, the unit of focal length is mm. The focal lengths shown in Table 13 were calculated using a design wavelength of 950 nm.

[0063] [Table 13]

[0064] In Examples 1 to 6, the second lens is a positive-power lens with its object side facing the object, and the third lens is a positive-power lens. This allows for correction of the increased spherical aberration caused by enlarging the aperture diameter to improve the brightness of the imaging lens system. As a result, an imaging lens system 11 with sufficient brightness for imaging inside a vehicle can be provided. In fact, in Examples 1 to 6, as shown in Figures 2(A), 4(A), 6(A), 8(A), 10(A), and 12(A), spherical aberration is suitably reduced. Therefore, in Examples 1 to 6, the imaging lens system 11 has high resolution. Also, in Examples 1 to 6, the F-number is 1.8, and the imaging lens system 11 has sufficient brightness for sensing inside a vehicle.

[0065] Furthermore, in Examples 1 to 6, the fact that the second lens L2 is a glass lens allows for sufficient suppression of focus shift due to changes in ambient temperature, thereby realizing an imaging lens system 11 with excellent resolution performance. In fact, as shown in Figures 2(A), 4(A), 6(A), 8(A), 10(A), and 12(A), spherical aberration can be suitably reduced in Examples 1 to 6.

[0066] Furthermore, in Examples 1 to 6, the F2 / F3 value satisfies the above condition (1), which allows for a suitable reduction in the amount of focus shift due to changes in ambient temperature, thereby realizing an imaging lens system 11 with good imaging performance. In fact, in Examples 1 to 6, as shown in Figures 2(A), 4(A), 6(A), 8(A), 10(A), and 12(A), spherical aberration is suitably reduced.

[0067] Furthermore, in Examples 1 to 6, by satisfying the above condition (2) for the value of (L2-L3) / TTL, the third lens L3 can achieve both a larger aperture and good resolution performance. In addition, it is possible to suppress the deterioration of optical performance caused by changes in ambient temperature. In fact, in Examples 1 to 6, as shown in Figures 2(A), 4(A), 6(A), 8(A), 10(A), and 12(A), spherical aberration can be suitably reduced.

[0068] Furthermore, in Examples 1 to 6, the value of T1 / F satisfies the above condition (3). In other words, by controlling the thickness T1 at the center of the first lens to an appropriate thickness, it is possible to balance maintaining imaging performance with miniaturization. In fact, in Examples 1 to 6, as shown in Figures 2, 4, 6, 8, 10, and 12, various aberrations can be suitably reduced.

[0069] Furthermore, by providing the camera module 10 with an imaging lens system 11, it is possible to provide a camera module 10 that has sufficient brightness for imaging inside the vehicle.

[0070] (Embodiment 3) Figure 13 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 13 is an example of an arrangement illustrating the mounting position of the imaging device 50 on the vehicle 40. The imaging device 50 mounted on the vehicle 40 can also be called an in-vehicle camera and can be installed in various locations on the vehicle 40. For example, the first imaging device 50a may be placed on or near the front bumper as a camera to monitor the area in front of the vehicle 40 while it is in motion. The second imaging device 50b, which also monitors the area in front, may be placed near the rearview mirror inside the vehicle 40. The third imaging device 50c may be placed on the dashboard or inside the instrument panel, etc., as a camera to monitor the driver's driving condition. The fourth imaging device 50d may be installed at the rear of the vehicle 40 for use as a rear monitor. The imaging devices 50a and 50b can be called front cameras. The third imaging device 50c can be called an in-camera. The fourth imaging device 50d can be called a rear camera. The imaging device 50 is not limited to these, and includes imaging devices installed in various positions, such as a left-side camera that images the left rear side and a right-side camera that images the right rear side.

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

[0072] Figure 14 shows the configuration of the imaging device 50 that constitutes the in-vehicle system shown in Figure 13. As shown in the figure, the imaging device 50 according to one embodiment comprises a control unit 52, a storage unit 54, and a camera module 10.

[0073] The control unit 52 controls the camera module 10 and processes the electrical signals output from the image sensor 12 of the camera module 10. This control unit 52 may be configured as a processor, for example. The control unit 52 may also include one or more processors. The processors may include general-purpose processors that load a specific program and execute a specific function, and dedicated processors specialized for specific processing. Dedicated processors may include application-specific integrated circuits (ICs). Application-specific integrated circuits are also called ASICs (Application Specific Integrated Circuits). The processors may also include programmable logic devices. Programmable logic devices are also called PLDs (Programmable Logic Devices). PLDs may include field-programmable gate arrays (FPGAs). The control unit 52 may be either a system-on-a-chip (SoC) or a system-in-a-package (SiP) in which one or more processors cooperate.

[0074] The storage unit 54 stores various information or parameters related to the operation of the imaging device 50. The storage unit 54 may be composed of, for example, a semiconductor memory. The storage unit 54 may function as a work memory for the control unit 52. The storage unit 54 may store captured images. The storage unit 54 may store various parameters, etc., for the control unit 52 to perform detection processing based on the captured images. The storage unit 54 may be included in the control unit 52.

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

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

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

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

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

Claims

1. The lens is characterized by comprising, in order from the object side toward the image side, a first lens having a meniscus shape with the object side surface facing the object side concave, an aperture diaphragm, a second lens having positive power with the object side surface facing the object side convex, a third lens having positive power, a fourth lens having a meniscus shape with the object side surface facing the object side concave and having positive power, and a fifth lens having negative power. Imaging lens system.

2. The imaging lens system according to claim 1, characterized in that the second lens is a glass lens.

3. The imaging lens system according to claim 1, characterized in that, when the focal length of the second lens is defined as F2 and the focal length of the third lens is defined as F3, the following condition (1) is satisfied. 0.45<F2 / F3<1.15...(1)

4. When the distance along the optical axis between the image side of the second lens and the object side of the third lens is defined as (L2-L3), and the distance along the optical axis from the object side of the first lens to the image plane of the image sensor is defined as TTL, the following condition (2) is satisfied, the following condition is satisfied: The imaging lens system according to claim 1. (L2-L3) / TTL<0.04...(2)

5. The imaging lens system according to claim 1, characterized in that it satisfies the following condition (3), when the thickness of the center of the first lens is defined as T1 and the focal length of the entire imaging lens system is defined as F. 0.2<T1 / F<0.45...(3)

6. A camera module comprising an imaging lens system according to any one of claims 1 to 5, and an image sensor that converts light focused through the imaging lens system into an electrical signal.

7. An in-vehicle system installed in a vehicle, The camera module according to claim 6, 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.

8. A mobile body equipped with the vehicle-mounted system described in claim 7, 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