Imaging lens system, camera module, vehicle-mounted system, and mobile object
A mixed glass-plastic lens system with controlled focal length and shape factors addresses the expense and size issues of all-glass systems, offering a compact and effective imaging solution.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MAXELL LTD
- Filing Date
- 2025-12-11
- Publication Date
- 2026-06-25
AI Technical Summary
Existing imaging lens systems for vehicles are expensive due to the use of all-glass lenses and suffer from focus shift due to temperature changes, and they are too large for narrow spaces.
An imaging lens system comprising a combination of glass and plastic lenses, where the third lens is glass with a low thermal expansion coefficient, and other lenses are plastic, with specific focal length and shape factor conditions to minimize aberrations and size.
The system provides a cost-effective, compact lens system with good imaging performance by reducing focus shift and aberrations, enabling miniaturization while maintaining optical quality.
Smart Images
Figure JP2025043220_25062026_PF_FP_ABST
Abstract
Description
Imaging lens system, camera module, vehicle-mounted system, mobile body
[0001] The present invention relates to an imaging lens system, a camera module, a vehicle-mounted system, and a mobile body.
[0002] Patent Document 1 describes an in-vehicle imaging lens system composed of six glass lenses.
[0003] Japanese Patent Application Laid-Open No. 2019-211598
[0004] In the imaging lens system described in Patent Document 1, since all the lenses are glass lenses, there is a problem that the imaging lens system becomes expensive. On the other hand, when a relatively inexpensive plastic lens is included in the configuration of the imaging lens system, there is a problem that focus shift occurs due to changes in environmental temperature. In addition, the size of the imaging lens system described in Patent Document 1 is large as a lens system for an in-vehicle camera mounted in a narrow space.
[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, a vehicle-mounted system, and a mobile body that are relatively inexpensive, have good imaging performance, and are small in size.
[0006] The imaging lens system according to one embodiment includes, in order from the object side toward the image side, a first lens having a negative power with a concave surface facing the image side on the image side surface, a second lens having a meniscus shape with a concave surface facing the object side on the object side surface, an aperture stop, a third lens having a positive power, a fourth lens having a convex surface facing the object side on the object side surface, a fifth lens having a convex surface facing the image side on the image side surface, and a sixth lens, the fourth lens and the fifth lens form a cemented lens, the third lens is a glass lens, and at least one of the lenses other than the third lens is a plastic lens.
[0007] According to the present invention, it is possible to provide an imaging lens system, a camera module, a vehicle-mounted system, and a mobile body that are relatively inexpensive, have good imaging performance, and are small in size.
[0008] This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 1. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 1. This is an astigmatism / field curvature diagram of the imaging lens system of Example 1. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 2. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 2. This is an astigmatism / field curvature diagram of the imaging lens system of Example 2. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 3. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 3. This is an astigmatism / field curvature diagram of the imaging lens system of Example 3. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 4. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 4. This is an astigmatism / field curvature diagram of the imaging lens system of Example 4. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 5. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 5. This is an astigmatism / field curvature diagram of the imaging lens system of Example 5. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 6. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 6. This is an astigmatism / field curvature diagram of the imaging lens system of Example 6. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 7. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 7. This is an astigmatism / field curvature diagram of the imaging lens system of Example 7. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 8. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 8. This is an astigmatism / field curvature diagram of the imaging lens system of Example 8. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 9. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 9. This is an astigmatism / image field curvature diagram of the imaging lens system of Example 9. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 10. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 10. This is an astigmatism / image field curvature diagram of the imaging lens system of Example 10. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 11.This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 11. This is an astigmatism / field curvature diagram of the imaging lens system of Example 11. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 12. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 12. This is an astigmatism / field curvature diagram of the imaging lens system of Example 12. This is a cross-sectional view showing the configuration of the camera module and imaging lens system according to Example 13. This is a spherical aberration diagram (longitudinal aberration diagram) of the imaging lens system of Example 13. This is an astigmatism / field curvature diagram of the imaging lens system of Example 13. This is a schematic diagram of a vehicle equipped with an in-vehicle system comprising a camera module according to one embodiment of the present invention. This is a block diagram showing the configuration of the imaging device constituting the in-vehicle system of Figure 27.
[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 robust infrastructure. They target "3.6 By 2020, halve the number of road traffic fatalities and injuries worldwide" of "3. Good Health and Well-being" in 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 negative power with its image side facing concave toward the image side, a second lens having a meniscus shape with its object side facing concave toward the object side, an aperture diaphragm, a third lens having positive power, a fourth lens with its object side facing convex toward the object side, a fifth lens with its image side facing convex toward the image side, and a sixth lens, wherein the fourth and fifth lenses form a cemented lens, the third lens is a glass lens, and at least one of the lenses other than the third lens is a plastic lens.
[0010] This makes it possible to provide a relatively inexpensive, compact imaging lens system with good imaging performance. Specifically, by having at least one of the lenses other than the third lens be a plastic lens, a relatively inexpensive imaging lens system can be realized. On the other hand, using a plastic lens increases the amount of focus shift of the imaging lens system due to changes in ambient temperature. However, by making the third lens, which has a large contribution to the overall focal length of the imaging lens system, a glass lens with a relatively small coefficient of linear expansion, the amount of focus shift due to changes in ambient temperature can be reduced, and an imaging lens system with good imaging performance can be realized. Therefore, a relatively inexpensive, compact imaging lens system with good imaging performance can be provided. Furthermore, when the focal length of the third lens is defined as F3 and the overall focal length of the imaging lens system is defined as F, it is preferable that the following condition (1) is satisfied: 1.0 < F3 / F < 1.5 ... (1) By satisfying condition (1) of the imaging lens system, the overall focal length of the imaging lens system can be shortened, and the imaging lens system can be made smaller. More specifically, if the F3 / F value is less than 1, the power of the third lens is too strong, resulting in excessive spherical aberration in the third lens, which is undesirable. On the other hand, if the F3 / F value is greater than 1.5, the power of the third lens is too weak, resulting in a longer focal length for the entire imaging lens system, making it impossible to miniaturize the imaging lens system. The lower limit of F3 / F is more preferably 1.05, and even more preferably 1.10. The upper limit of F3 / F is more preferably 1.45, and even more preferably 1.40.
[0011] Furthermore, when the shape factor of the first lens is defined as SF1, it is preferable that the following condition (2) is satisfied: -6 < SF1 < -3 ... (2) Here, the shape factor SF1 is defined as SF1 = -(R1 + R2) / (R1 - R2), where R1 is defined as the radius of curvature on the object side of the first lens and R2 is defined as the radius of curvature on the image side of the first lens. By satisfying condition (2), the imaging lens system can reduce the occurrence of various aberrations and realize an imaging lens system with good imaging performance. Specifically, if the value of SF1 is less than -6, the spherical aberration generated in the first lens becomes too large, which is undesirable. Also, the absolute value of the radius of curvature R1 on the object side of the first lens and the absolute value of the radius of curvature R2 on the image side become close, making it difficult to center the first lens when it is formed by centering. On the other hand, if the value of SF1 is greater than -3, the occurrence of coma aberration and astigmatism in the first lens becomes too large, which is undesirable. The lower limit of SF1 is more preferably -5.7, and even more preferably -5.5. The upper limit of SF1 is more preferably -3.3, and even more preferably -3.5.
[0012] Furthermore, it is preferable that the imaging lens system satisfies the following condition (3) when the focal length of the first lens is defined as F1: F1 / F < -1.5 ... (3) By satisfying the above condition (3) of the imaging lens system, the occurrence of distortion aberration in the first lens can be reduced, and an imaging lens system with good imaging performance can be realized. Specifically, if the value of F1 / F is greater than -1.5, the power of the first lens is too strong, and large distortion aberration occurs. The upper limit of F1 / F is more preferably -2.0, and even more preferably -2.5. The lower limit of F1 / F is preferably -4.5, and even more preferably -4.0. If the value of F1 / F is less than -4.0, the power of the first lens becomes too weak, making it difficult to secure a sufficient angle of view, which is undesirable.
[0013] Furthermore, the imaging lens system preferably satisfies the following condition (4) when the combined focal length of the third to sixth lenses is defined as FR: 0.5 < FR / F < 1.5 ... (4) By satisfying the above condition (4) of the imaging lens system, the occurrence of spherical aberration can be reduced and the imaging lens system can be miniaturized. Specifically, if the value of FR / F is less than 0.5, the spherical aberration generated in the third lens becomes too large. Also, the back focus (the distance on the optical axis from the image side of the sixth lens to the image plane) becomes too short. On the other hand, if the value of FR / F is greater than 1.5, the power of the third lens becomes too weak, the focal length of the rear group becomes too long, and the imaging lens system cannot be miniaturized. The lower limit of FR / F is more preferably 0.6, and even more preferably 0.7. The upper limit of FR / F is more preferably 1.4, and even more preferably 1.3.
[0014] Furthermore, it is preferable that the image surface of the sixth lens has a shape with an inflection point. By having an inflection point on the image surface of the sixth lens, image field curvature can be corrected.
[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 focused through the imaging lens system into an electrical signal. This makes it possible to provide a relatively inexpensive, compact camera module with good imaging performance.
[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. (Embodiment 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 Embodiment 1 comprises, in order from the object side to the image side, a front group Gf consisting of a first lens L1 and a second lens L2, an aperture diaphragm (STOP), and a rear group Gr consisting of a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6. The imaging plane of the imaging lens system 11 is indicated by IMG. The first lens L1 and the third lens L3 are glass lenses. The second lens L2, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are plastic lenses. Optical filters (infrared transmission filters, visible / infrared bandpass filters, etc.) are 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.
[0019] The first lens L1 is a lens with negative power. The object side S1 of the first lens L1 has a spherical shape with a convex surface facing the object. The image side S2 of the first lens L1 has a spherical shape with a concave surface facing the image.
[0020] The second lens L2 is a positive power meniscus lens. The object side S3 of the second lens L2 has an aspherical shape with a concave surface facing the object. The image side S4 of the second lens L2 has an aspherical shape with a convex surface facing the image.
[0021] 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 second lens L2 and the third lens L3.
[0022] The third lens L3 is a positive-power lens. The object-side surface S6 of the third lens L3 has a spherical shape with its convex surface facing the object. The image-side surface S7 of the third lens L3 also has a spherical shape with its convex surface facing the image.
[0023] The fourth lens L4 is a negative power lens. The object side S8 of the fourth lens L4 has an aspherical shape with a convex surface facing the object. The image side S9 of the fourth lens L4 has an aspherical shape with a concave surface facing the image.
[0024] The fifth lens L5 is a positive power lens. The object side surface S10 of the fifth lens L5 has an aspherical shape with a convex surface facing the object. In addition, the image side surface S11 of the fifth lens L5 has an aspherical shape with a convex surface facing the image side, at least near the optical axis OA.
[0025] 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 together by an adhesive layer of a predetermined thickness. By forming a cemented lens with the fourth lens L4 and the fifth lens L5, chromatic aberration and higher-order spherical aberration can be corrected.
[0026] The sixth lens L6 is a negative power lens. The object side surface S12 of the sixth lens L6 has an aspherical shape with a concave surface facing the object side. The image side surface S13 of the sixth lens L6 has an aspherical shape with an inflection point, with a concave surface facing the image side, at least near the optical axis OA.
[0027] 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 Embodiment 1. In addition, 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.
[0028] 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 with respect to the d line, and the Abbe number νd with respect to the d line. Also, in Table 1, surfaces marked with an asterisk (*) are aspherical. Furthermore, the imaging lens system 11 of Example 1 has an F-number of 1.85 and a half-angle of view (ω) of 32°.
[0029]
[0030] The aspherical shape used on the lens surface is determined by using α, 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, with 4th, 6th, 8th, 10th, 12th, 14th, and 16th order aspherical coefficients respectively. ４ , α ６ , α ８ , α １０ , α １２ , α １４ , α １６ When this is the case, it can be expressed by the following equation.
[0031] 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, "-1.18536E-03" is equivalent to "-1.18536 × 10 －３ This means "[...]." The numerical representation is the same for the following table.
[0032]
[0033] Next, aberration will be described with reference to the drawings. FIG. 2 shows a spherical aberration diagram (longitudinal aberration diagram) and an astigmatism / field curvature diagram in the imaging lens system 11 of Example 1. In the longitudinal aberration diagram of FIG. 2A, the horizontal axis indicates the position where the light ray intersects the optical axis OA, and the vertical axis indicates the passing height (relative value) of the light ray on the entrance pupil. FIG. 2A shows the simulation results for the F line, d line, and C line. In the astigmatism / field curvature diagram of FIG. 2B, the horizontal axis indicates the distance in the direction of the optical axis OA, and the vertical axis indicates the angle of view. In the astigmatism / field curvature diagram of FIG. 2B, Sag shift indicates the imaging position in the sagittal ray bundle, and Tan shift indicates the imaging position in the tangential ray bundle. FIG. 2B shows the simulation results for a light ray with a wavelength of 546.1 nm.
[0034] (Example 2) FIG. 3 is a cross-sectional view showing the camera module 10 according to Example 2. Since the configuration of the imaging lens system 11 according to Example 2 has the same lens configuration as that of Example 1, the description thereof will be omitted. Hereinafter, the characteristic data of the imaging lens system 11 according to Example 2 will be described.
[0035] Table 3 shows the lens data of each lens surface of the imaging lens system 11 according to Example 2. Since the items shown in Table 3 are the same as those in Table 1, the description thereof will be omitted. In the imaging lens system 11 of Example 2, the F number is 1.85 and the semi-angle of view (ω) is 32°.
[0036]
[0037] Table 4 shows the aspherical coefficients for defining the aspherical shape of the lens surface that is an aspherical surface in the imaging lens system 11 of Example 2. In Table 4, the aspherical shape adopted for the lens surface is represented by the same formula as that of Example 1.
[0038]
[0039] FIG. 4 shows a spherical aberration diagram (longitudinal aberration diagram) and an astigmatism / field curvature diagram in the imaging lens system 11 of Example 2. Since the description of each aberration diagram shown in FIG. 4 is the same as that of FIG. 2, the description thereof will be omitted.
[0040] (Example 3) FIG. 5 is a cross-sectional view showing the camera module 10 according to Example 3. Since the configuration of the imaging lens system 11 according to Example 3 has the same lens configuration as that of Example 1, the description thereof is omitted. Hereinafter, the characteristic data of the imaging lens system 11 according to Example 3 will be described.
[0041] Table 5 shows the lens data of each lens surface of the imaging lens system 11 according to Example 3. Since the items shown in Table 5 are the same as those in Table 1, the description thereof is omitted. In addition, in the imaging lens system 11 of Example 3, the F number is 1.85 and the semi-aperture angle (ω) is 32°.
[0042]
[0043] Table 6 shows the aspherical coefficients for defining the aspherical shape of the lens surfaces that are aspherical in the imaging lens system 11 of Example 3. In Table 6, the aspherical shape adopted for the lens surface is represented by the same formula as that of Example 1.
[0044]
[0045] FIG. 6 shows the spherical aberration diagram (longitudinal aberration diagram) and the astigmatism / field curvature diagram in the imaging lens system 11 of Example 3. Since the description of each aberration diagram shown in FIG. 6 is the same as that in FIG. 2, the description thereof is omitted.
[0046] (Example 4) Figure 7 is a cross-sectional view showing a camera module 10 according to Example 4. In the imaging lens system 11 according to Example 4, the fourth lens L4 has positive power, the object side surface S8 has an aspherical shape with a convex surface facing the object, and the image side surface S9 has an aspherical shape with a convex surface facing the image. The fifth lens L5 has negative power, the object side surface S10 has an aspherical shape with a concave surface facing the object, and the image side surface S11 has an aspherical shape with a convex surface facing the image, at least near the optical axis OA. The sixth lens L6 has positive power, the object side surface S12 has an aspherical shape with a convex surface facing the object, at least near the optical axis OA, and the image side surface S13 has an aspherical shape with a concave surface facing the image, at least near the optical axis OA. The other configurations of the imaging lens system 11 according to Example 4 are the same as those of Example 1, so their description is omitted. The characteristic data of the imaging lens system 11 according to Example 4 will be described below.
[0047] 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 1.85 and a half-angle of view (ω) of 32°.
[0048]
[0049] Table 8 shows the aspheric coefficients used to define the aspherical shape of the lens surface 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.
[0050]
[0051] Figure 8 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature 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.
[0052] (Example 5) Figure 9 is a cross-sectional view showing a camera module 10 according to Example 5. In the imaging lens system 11 according to Example 5, the sixth lens L6 has negative power, the object side surface S12 has an aspherical shape with a convex surface facing the object side at least near the optical axis OA, and the image side surface S13 has an aspherical shape with a concave surface facing the image side at least near the optical axis OA. The other components of the imaging lens system 11 according to Example 5 have the same lens configuration as in Example 4, so their description will be omitted. The characteristic data of the imaging lens system 11 according to Example 5 will be described below.
[0053] 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 1.85 and a half-angle of view (ω) of 32°.
[0054]
[0055] Table 10 shows the aspheric coefficients for defining 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.
[0056]
[0057] Figure 10 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature 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.
[0058] (Example 6) Figure 11 is a cross-sectional view showing a camera module 10 according to Example 6. In the imaging lens system 11 according to Example 6, the sixth lens L6 has negative power, the object side surface S12 has an aspherical shape with a concave surface facing the object side, and the image side surface S13 has an aspherical shape with a concave surface facing the image side, at least near the optical axis OA. The other components of the imaging lens system 11 according to Example 6 have the same lens configuration as in Example 5, so their description will be omitted. The characteristic data of the imaging lens system 11 according to Example 6 will be described below.
[0059] 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 1.85 and a half-angle of view (ω) of 32°.
[0060]
[0061] 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.
[0062]
[0063] Figure 12 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature 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.
[0064] (Example 7) Figure 13 is a cross-sectional view showing a camera module 10 according to Example 7. In the imaging lens system 11 according to Example 7, the second lens L2 has negative power, the object side surface S3 has an aspherical shape with a concave surface facing the object side, and the image side surface S4 has an aspherical shape with a convex surface facing the image side. The other components of the imaging lens system 11 according to Example 7 have the same lens configuration as in Example 1, so their description will be omitted. The characteristic data of the imaging lens system 11 according to Example 7 will be described below.
[0065] Table 13 shows the lens data for each lens surface of the imaging lens system 11 according to Example 7. The items shown in Table 13 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 7 has an F-number of 1.85 and a half-angle of view (ω) of 32°.
[0066]
[0067] Table 14 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 7. In Table 14, the aspherical shape adopted for the lens surface is expressed by the same formula as in Example 1.
[0068]
[0069] Figure 14 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature diagram for the imaging lens system 11 of Example 7. The explanation of each aberration diagram shown in Figure 14 is the same as in Figure 2, so the explanation is omitted.
[0070] (Example 8) Figure 15 is a cross-sectional view showing a camera module 10 according to Example 8. In the imaging lens system 11 according to Example 8, the sixth lens L6 has negative power, the object side surface S12 has an aspherical shape with a convex surface facing the object side at least near the optical axis OA, and the image side surface S13 has an aspherical shape with a concave surface facing the image side at least near the optical axis OA. The other components of the imaging lens system 11 according to Example 8 have the same lens configuration as in Example 7, so their description will be omitted. The characteristic data of the imaging lens system 11 according to Example 8 will be described below.
[0071] Table 15 shows the lens data for each lens surface of the imaging lens system 11 according to Example 8. The items shown in Table 15 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 8 has an F-number of 1.85 and a half-angle of view (ω) of 32°.
[0072]
[0073] Table 16 shows the aspheric coefficients used to define the aspheric shape of the lens surface in the imaging lens system 11 of Example 8. In Table 16, the aspheric shape adopted for the lens surface is expressed by the same formula as in Example 1.
[0074]
[0075] Figure 16 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature diagram for the imaging lens system 11 of Example 8. The explanation of each aberration diagram shown in Figure 16 is the same as in Figure 2, so the explanation is omitted.
[0076] (Example 9) Figure 17 is a cross-sectional view showing a camera module 10 according to Example 9. The configuration of the imaging lens system 11 according to Example 9 has the same lens configuration as in Example 7, so its description will be omitted. The characteristic data of the imaging lens system 11 according to Example 9 will be described below.
[0077] Table 17 shows the lens data for each lens surface of the imaging lens system 11 according to Example 9. The items shown in Table 17 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 9 has an F-number of 1.85 and a half-angle of view (ω) of 32°.
[0078]
[0079] Table 18 shows the aspheric coefficients used to define the aspheric shape of the lens surface in the imaging lens system 11 of Example 9. In Table 18, the aspheric shape adopted for the lens surface is expressed by the same formula as in Example 1.
[0080]
[0081] Figure 18 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature diagram for the imaging lens system 11 of Example 9. The explanation of each aberration diagram shown in Figure 18 is the same as in Figure 2, so the explanation is omitted.
[0082] (Example 10) Figure 19 is a cross-sectional view showing a camera module 10 according to Example 10. In the imaging lens system 11 according to Example 10, the second lens L2 has negative power, the object side surface S3 has an aspherical shape with a concave surface facing the object side, and the image side surface S4 has an aspherical shape with a convex surface facing the image side. The other configurations of the imaging lens system 11 according to Example 10 are the same as those of Example 5, so their description will be omitted. The characteristic data of the imaging lens system 11 according to Example 10 will be described below.
[0083] Table 19 shows the lens data for each lens surface of the imaging lens system 11 according to Example 10. The items shown in Table 19 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 10 has an F-number of 1.85 and a half-angle of view (ω) of 32°.
[0084]
[0085] Table 20 shows the aspheric coefficients used to define the aspheric shape of the lens surface in the imaging lens system 11 of Example 10. In Table 20, the aspheric shape adopted for the lens surface is expressed by the same formula as in Example 1.
[0086]
[0087] Figure 20 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature diagram for the imaging lens system 11 of Example 10. The explanation of each aberration diagram shown in Figure 20 is the same as in Figure 2, so the explanation is omitted.
[0088] (Example 11) Figure 21 is a cross-sectional view showing a camera module 10 according to Example 11. In the imaging lens system 11 according to Example 11, the third lens L3 has positive power, the object side surface S6 has a spherical shape with a convex surface facing the object side, and the image side surface S7 has a spherical shape with a concave surface facing the image side. The other components of the imaging lens system 11 according to Example 11 have the same lens configuration as in Example 10, so their description will be omitted. The characteristic data of the imaging lens system 11 according to Example 11 will be described below.
[0089] Table 21 shows the lens data for each lens surface of the imaging lens system 11 according to Example 11. The items shown in Table 21 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 11 has an F-number of 1.85 and a half-angle of view (ω) of 32°.
[0090]
[0091] Table 22 shows the aspheric coefficients used to define the aspherical shape of the lens surface in the imaging lens system 11 of Example 11. In Table 22, the aspherical shape adopted for the lens surface is expressed by the same formula as in Example 1.
[0092]
[0093] Figure 22 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature diagram for the imaging lens system 11 of Example 11. The explanation of each aberration diagram shown in Figure 22 is the same as in Figure 2, so the explanation is omitted.
[0094] (Example 12) Figure 23 is a cross-sectional view showing a camera module 10 according to Example 12. The configuration of the imaging lens system 11 according to Example 12 has the same lens configuration as in Example 11, so its description will be omitted. The characteristic data of the imaging lens system 11 according to Example 12 will be described below.
[0095] Table 23 shows the lens data for each lens surface of the imaging lens system 11 according to Example 12. The items shown in Table 23 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 12 has an F-number of 1.85 and a half-angle of view (ω) of 32°.
[0096]
[0097] Table 24 shows the aspheric coefficients used to define the aspherical shape of the lens surface in the imaging lens system 11 of Example 12. In Table 24, the aspherical shape adopted for the lens surface is expressed by the same formula as in Example 1.
[0098]
[0099] Figure 24 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature diagram for the imaging lens system 11 of Example 12. The explanation of each aberration diagram shown in Figure 24 is the same as in Figure 2, so the explanation is omitted.
[0100] (Example 13) Figure 25 is a cross-sectional view showing a camera module 10 according to Example 13. The configuration of the imaging lens system 11 according to Example 13 has the same lens configuration as in Example 10, so its description will be omitted. The characteristic data of the imaging lens system 11 according to Example 13 will be described below.
[0101] Table 25 shows the lens data for each lens surface of the imaging lens system 11 according to Example 13. The items shown in Table 25 are the same as those in Table 1, so their explanation is omitted. In addition, the imaging lens system 11 of Example 13 has an F-number of 1.85 and a half-angle of view (ω) of 32°.
[0102]
[0103] Table 26 shows the aspheric coefficients used to define the aspherical shape of the lens surface in the imaging lens system 11 of Example 13. In Table 26, the aspherical shape adopted for the lens surface is expressed by the same formula as in Example 1.
[0104]
[0105] Figure 26 shows the spherical aberration diagram (longitudinal aberration diagram) and astigmatism / field curvature diagram for the imaging lens system 11 of Example 13. The explanation of each aberration diagram shown in Figure 26 is the same as in Figure 2, so the explanation is omitted.
[0106] Tables 27 to 29 show the focal lengths F1 of the first lens L1, F2 of the second lens L2, F3 of the third lens L3, F4 of the fourth lens L4, F5 of the fifth lens L5, F6 of the sixth lens L6, the total focal length F of the optical system of the imaging lens system 11, the F1 / F values, F2 / F values, F3 / F values, F4 / F values, F5 / F values, F6 / F values, FR / F values, and SF1 values. In Tables 27 to 29, the unit of focal length is mm. The focal lengths shown in Tables 27 to 29 were calculated using a design wavelength of 546.1 nm.
[0107]
[0108]
[0109]
[0110] In Examples 1 to 13, the use of plastic lenses for the second lens L2 and the fourth to sixth lenses L4 to L6 allows for the realization of a relatively inexpensive imaging lens system 11. Furthermore, by using a glass lens with a relatively small coefficient of thermal expansion for the third lens L3, which has a large contribution to the overall focal length F of the imaging lens system 11, the amount of focus shift due to changes in ambient temperature can be reduced, resulting in an imaging lens system 11 with good imaging performance. In fact, as shown in Figures 2A, 4A, ..., 26A, spherical aberration can be suitably reduced in Examples 1 to 13. Moreover, in Examples 1 to 13, by satisfying condition (1) of the imaging lens system 11, the overall focal length F of the imaging lens system 11 can be shortened, enabling miniaturization of the imaging lens system 11. This makes it possible to provide a relatively inexpensive, compact imaging lens system 11 with good imaging performance.
[0111] Furthermore, in Examples 1 to 13, by satisfying the condition equation (2), the occurrence of various aberrations can be reduced, and an imaging lens system 11 with good imaging performance can be realized. In fact, in Examples 1 to 13, as shown in Figures 2, 4, ..., 26, various aberrations can be suitably reduced. In addition, when forming the first lens L1 by centering, it becomes easier to center it.
[0112] Furthermore, in Examples 1 to 13, by satisfying the above condition (3) of the imaging lens system 11, the occurrence of distortion aberration in the first lens L1 can be reduced, and an imaging lens system 11 with good imaging performance can be realized.
[0113] Furthermore, in Examples 1 to 13, by satisfying the above condition (4) of the imaging lens system 11, the occurrence of spherical aberration can be reduced, and the imaging lens system 11 can be miniaturized. In fact, in Examples 1 to 13, as shown in Figures 2A, 4A, ..., 26A, spherical aberration can be suitably reduced.
[0114] Furthermore, in Examples 1 to 13, the image curvature can be corrected by having an inflection point on the image surface of the sixth lens L6. In fact, in Examples 1 to 13, as shown in Figures 2B, 4B, ..., 26B, the image curvature can be suitably reduced.
[0115] Furthermore, by including an imaging lens system 11 in the camera module 10, it is possible to provide a relatively inexpensive, compact camera module 10 with good imaging performance.
[0116] (Embodiment 3) Figure 27 is a schematic diagram of a vehicle 40 equipped with an in-vehicle system comprising an imaging device 50 including an imaging lens system 11 according to Embodiment 1 or Embodiment 2 and an image sensor 12 that converts the light focused through thereon into an electrical signal. As shown in the figure, the imaging device 50 can be mounted on the vehicle 40, and Figure 27 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 that monitors the area in front of the vehicle 40 when it is in motion. The second imaging device 50b that 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 as a camera that monitors the driver's driving conditions. 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.
[0117] 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, as described later, 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 vehicle-to-vehicle 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, or 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.
[0118] Figure 28 shows the configuration of the imaging device 50 that constitutes the in-vehicle system shown in Figure 27. 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.
[0119] 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 specific programs and execute specific functions, 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.
[0120] 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.
[0121] As described 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.
[0122] 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.
[0123] 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.
[0124] 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.
[0125] This application claims priority based on Japanese Patent Application No. 2024-224441, filed on 19 December 2024, and incorporates all of its disclosures herein. Potential for industrial use
[0126] This allows us to provide relatively inexpensive, compact imaging lens systems, camera modules, in-vehicle systems, and mobile devices with good imaging performance.
[0127] 10 Camera module 11 Imaging lens system 12 Image sensor 40 Vehicle (mobile body) 42 Information processing device (processing device) 43 Display device (output device) 50 Imaging device 52 Control unit L1 First lens L2 Second lens L3 Third lens L4 Fourth lens L5 Fifth lens L6 Sixth lens STOP Aperture Gf Front group Gr Rear group IRCF Infrared cut filter IMG Image plane OA Optical axis
Claims
1. An imaging lens system comprising, in order from the object side toward the image side, a first lens having negative power with its image side facing concave toward the image side, a second lens having a meniscus shape with its object side facing concave toward the object side, an aperture diaphragm, a third lens having positive power, a fourth lens with its object side facing convex toward the object side, a fifth lens with its image side facing convex toward the image side, and a sixth lens, wherein the fourth lens and the fifth lens form a cemented lens, the third lens is a glass lens, and at least one of the lenses other than the third lens is a plastic lens.
2. The imaging lens system according to claim 1, characterized in that, when the focal length of the third lens is defined as F3 and the focal length of the entire imaging lens system is defined as F, the following condition (1) is satisfied: 1.0 < F3 / F < 1.5 ... (1) 3. The imaging lens system according to claim 1, characterized in that, when the shape factor of the first lens is defined as SF1, the following condition (2) is satisfied: -6 < SF1 < -3 ... (2) 4. The imaging lens system according to claim 1, characterized in that, when the focal length of the first lens is defined as F1, the following condition (3) is satisfied: F1 / F < -1.5 ... (3) 5. The imaging lens system according to claim 1, characterized in that when the combined focal length of the third to sixth lenses is defined as FR, the following condition (4) is satisfied: 0.5 < FR / F < 1.5 ... (4) 6. The imaging lens system according to claim 1, characterized in that the image surface of the sixth lens has a shape having an inflection point.
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 mounted on a vehicle, comprising: a camera module as described in claim 7; and an information processing device that processes an image captured by the image sensor of the camera module and recognizes an object in the image captured.
9. A mobile body equipped with the in-vehicle system described in claim 8, wherein the in-vehicle system further comprises an output device that outputs information to the occupants, and the information processing device is configured to output recognition information of the object to the output device.