An automotive lens optical system suitable for 8MP chips

Abstract

The present invention belongs to the technical field of vehicle-mounted imaging lenses, and discloses a vehicle-mounted lens optical system suitable for an 8MP chip, comprising: a front lens group, an aperture, a rear lens group, a filter and an imaging surface arranged coaxially from the front object side to the rear image side; the front lens group has a negative focal power; the rear lens group has a positive focal power; the aperture is located between the front lens group and the rear lens group, and the aperture through hole center is located on the optical axis; the imaging surface is located on the rear side of the rear lens group, and the filter is located between the rear lens group and the imaging surface; the ratio of the combined focal length Fa of the front lens group and the combined focal length Fb of the rear lens group satisfies ‑2≥Fa / Fb≥‑23; wherein Fa is the combined focal length value of the front lens group, and Fb is the combined focal length value of the rear lens group. The present invention improves the resolution capability of the entire lens group. At the same time, the length and aperture of the lens are also effectively controlled, and high-definition imaging of a large target surface is achieved using a small-aperture lens.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle-mounted imaging lenses and relates to a vehicle-mounted lens optical system suitable for an 8MP chip. Background Art

[0002] In recent years, with the increasing demand for safe driving, vehicle-mounted lenses have developed rapidly, and the use of vehicle-mounted lenses has evolved from providing internal and external environment monitoring to advanced driver assistance systems (ADAS). Existing vehicle-mounted lenses have insufficient image clarity and poor image contrast, which cannot meet people's current demand for safe driving. In the ADAS system, the image-based assisted driving system is its core technology, so the development of high-resolution and high-contrast vehicle-mounted lenses has become a key technology for the development of the ADAS system.

[0003] Many domestic automotive lens development companies have patents and reports on automotive lenses, but those related to ADAS systems include Ningbo Sunny Automotive Optical Technology Co., Ltd. and Jiangxi Lianchuang Electronics Co., Ltd. Patent 201810771948.5 of Jiangxi Lianchuang Electronics Co., Ltd. discloses an automotive lens with a field of view greater than 160°, focal length f'=1.28mm, F number=2.8, and total optical length TTL=12.5mm. This design has the characteristics of a large field of view, short focal length, and large F number, which inevitably leads to the disadvantages of low spatial resolution and low illumination on the image plane, and cannot provide images with high resolution and contrast. Patent 200920122166.5 of Ningbo Sunny Automotive Optics Technology Co., Ltd. discloses a megapixel large-aperture automotive front-view lens with a field of view of 100°, a focal length of f'=6.3mm, an F number=1.62, and a total optical length TTL=24mm. Compared with patent 201810771948.5, its design focal length is increased while the spatial resolution is greatly improved. The reduction in F number also improves the image plane illumination, but its field of view is only 100°, which seriously affects the imaging range and limits its usage environment. Summary of the invention

[0004] (I) Purpose of the invention

[0005] The purpose of the present invention is to provide a vehicle-mounted lens optical system suitable for high-definition imaging of 8MP chips in order to solve the problems of insufficient image clarity and poor image contrast of existing vehicle-mounted lenses.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a vehicle-mounted lens optical system suitable for an 8MP chip, which includes: a front lens group 1, an aperture 2, a rear lens group 3, a filter 4 and an imaging surface 5, which are coaxially arranged from the front object side to the rear image side; the front lens group 1 has a negative optical focal length; the rear lens group 3 has a positive optical focal length; the aperture 2 is located between the front lens group 1 and the rear lens group 3, and the center of the aperture 2 is located on the optical axis; the imaging surface 5 is located on the rear side of the rear lens group 3, and the filter 4 is located between the rear lens group 3 and the imaging surface 5; the ratio of the combined focal length Fa of the front lens group 1 to the combined focal length Fb of the rear lens group 3 satisfies -2≥Fa / Fb≥-23; wherein Fa is the combined focal length value of the front lens group 1, and Fb is the combined focal length value of the rear lens group 3.

[0008] Among them, the front lens group 1 includes, from the object side to the image side, objective lens 1 1-1, objective lens 2 1-2 and objective lens 3 1-3; objective lens 1-1 has a negative optical focal length, and the front surface of objective lens 1 is convex; objective lens 2 1-2 has a negative optical focal length, and the front surface of objective lens 2 is concave; objective lens 3 1-3 has a positive optical focal length and is a double convex lens.

[0009] Among them, the rear lens group 3 includes, from the object side to the image side, objective lens four 3-1, objective lens five 3-2, objective lens six 3-3 and objective lens seven 3-4; objective lens four 3-1 has positive optical focal length and is a meniscus lens, and the rear surface of objective lens four is convex; objective lens five 3-2 has positive optical focal length and is a double convex lens; objective lens six 3-3 has negative optical focal length and is a cemented lens, which is composed of objective lens six positive lens 3-3a and objective lens six negative lens 3-3b cemented together; objective lens six positive lens 3-3a has positive optical focal length and is a double convex lens; objective lens six negative lens 3-3b has negative optical focal length and is a double concave lens; objective lens seven 3-4 has positive optical focal length and is a meniscus lens, and the front surface of objective lens seven is convex.

[0010] (III) Beneficial effects

[0011] The vehicle-mounted lens optical system suitable for 8MP chips provided by the above technical solution has the following beneficial effects:

[0012] (1) It can achieve high-definition imaging and is suitable for 8MP chips. The system uses a combination of spherical lenses and aspherical lenses. The optical system has a small F number and a large aperture, while providing a special form of chromatic aberration and distortion, ensuring the illumination of the image plane within the horizontal 120° field of view and improving the resolution of the entire lens set. At the same time, the length and aperture of the lens are also effectively controlled, and high-definition imaging of a large target surface is achieved using a small-aperture lens.

[0013] (2) During the design process, the material's expansion coefficient and stability were taken into consideration, and the athermal design concept was introduced. By matching optical materials with structural materials, the athermal design of the optomechanical system was achieved, ensuring the imaging quality of the system within the temperature range of -40°C to 115°C, which can meet the needs of different usage environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the composition and optical path of a vehicle-mounted lens in one embodiment of the present invention.

[0015] Figure 2 It is a modulation transfer function characteristic curve diagram of a vehicle-mounted lens in a specific embodiment of the present invention.

[0016] Figure 3 It is a distortion characteristic curve diagram of a vehicle-mounted lens in a specific embodiment of the present invention.

[0017] Figure 4 It is an axial chromatic aberration curve diagram of a vehicle-mounted lens in a specific embodiment of the present invention.

[0018] Figure 5 It is a vertical axis chromatic aberration curve diagram of a vehicle-mounted lens in a specific embodiment of the present invention.

[0019] Figure 6 It is a relative illumination curve diagram of a vehicle-mounted lens in a specific embodiment of the present invention.

[0020] Among them: front lens group 1, objective lens 1-1, objective lens 2 1-2, objective lens 3 1-3, aperture 2, rear lens group 3, objective lens 4 3-1, objective lens 5 3-2, objective lens 6 3-3, objective lens 7 3-4, filter 4, imaging surface 5; objective lens 1 front surface S1, objective lens 1 rear surface S2, objective lens 2 front surface S3, objective lens 2 rear surface S4, objective lens 3 front surface S5, objective lens 3 rear surface S6, objective lens 4 front surface S7, objective lens 4 rear surface S8, objective lens 5 front surface S9, objective lens 5 rear surface S10, objective lens 6 front surface S11, objective lens 6 bonding surface S12, objective lens 6 rear surface S13, objective lens 7 front surface S14, objective lens 7 rear surface S15, filter front surface S16, filter rear surface S17. DETAILED DESCRIPTION

[0021] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0022] like Figure 1As shown, the vehicle-mounted lens optical system of this embodiment includes a front lens group 1, an aperture 2, a rear lens group 3, a filter 4 and an imaging surface 5. The front lens group 1 has a negative focal power; the rear lens group 3 has a positive focal power; the aperture 2 is located between the front lens group 1 and the rear lens group 3, and the center of the aperture 2 is located on the optical axis; the imaging surface 5 is located on the side of the rear lens group 3 away from the aperture 2 and the front lens group 1, and the filter 4 is located between the rear lens group 3 and the imaging surface 5.

[0023] For the convenience of description, the front surface and the rear surface of each lens in the front lens group 1 and the rear lens group 3 are respectively expressed by the front surface S1 of objective lens one, the rear surface S2 of objective lens one, the front surface S3 of objective lens two, the rear surface S4 of objective lens two, the front surface S5 of objective lens three, the rear surface S6 of objective lens three, the front surface S7 of objective lens four, the rear surface S8 of objective lens four, the front surface S9 of objective lens five, the rear surface S10 of objective lens five, the front surface S11 of objective lens six, the bonding surface S12 of objective lens six, the rear surface S13 of objective lens six, the front surface S14 of objective lens seven, the rear surface S15 of objective lens seven, the front surface S16 of filter, and the rear surface S17 of filter.

[0024] The ratio of the combined focal length Fa of the front lens group and the combined focal length Fb of the rear lens group satisfies -2≥Fa / Fb≥-23; wherein Fa is the combined focal length value of the front lens group, and Fb is the combined focal length value of the rear lens group. Based on this focal length ratio, the vehicle-mounted lens has the characteristics of a small F number, a clear image, and a horizontal field of view greater than or equal to 120°.

[0025] In the above-mentioned vehicle-mounted lens, the front lens group 1 includes, from the object side to the image side, the objective lens 1-1, the objective lens 2-2 and the objective lens 3-3; the objective lens 1-1 has a negative focal length, and the front surface S1 of the objective lens 1 is a convex surface; the objective lens 2-1-2 has a negative focal length, and the front surface S3 of the objective lens 2 is a concave surface; the objective lens 3-1-3 has a positive focal length and is a double convex lens. After the imaging light beam enters the front lens group 1, it passes through the objective lens 1-1, the objective lens 2-2 and the objective lens 3-1-3 in sequence.

[0026] In this embodiment, the components of the front lens group 1 of the vehicle-mounted lens should also meet the following conditions:

[0027] The objective lens 1-1 also satisfies: N1≥1.7, V1≤50; wherein N1 is the refractive index of the objective lens 1-1, and V1 is the Abbe number of the objective lens 1-1;

[0028] The objective lens 1-2 also satisfies: N2≥1.7, V2≤50; wherein N2 is the refractive index of the objective lens 1-2, and V2 is the Abbe number of the objective lens 1-2;

[0029] The objective lens three 1-3 also satisfies: N3≥1.7, V3≤50; wherein N3 is the refractive index of the objective lens three 1-3, and V3 is the Abbe number of the objective lens three 1-3.

[0030] The above-mentioned vehicle-mounted lens, the rear lens group 3 includes from the object side to the image side: objective lens 4 3-1, objective lens 5 3-2, objective lens 6 3-3 and objective lens 7 3-4 in sequence; objective lens 4 3-1 has positive focal power and is a meniscus lens, and the rear surface S8 of objective lens 4 is convex; objective lens 5 3-2 has positive focal power and is a double convex lens; objective lens 6 3-3 has negative focal power and is a cemented lens, which is composed of objective lens 6 positive lens 3-3a and objective lens 6 negative lens 3-3b; objective lens 6 positive lens 3-3a has positive focal power and is a double convex lens; objective lens 6 negative lens 3-3b has negative focal power and is a double concave lens; objective lens 7 3-4 has positive focal power and is a meniscus lens, and the front surface S14 of objective lens 7 is convex. The imaging light beam enters the rear lens group 3 and passes through objective lens 4 3-1, objective lens 5 3-2, objective lens 6 3-3 and objective lens 7 3-4 in sequence.

[0031] In this embodiment, the components of the rear lens group 3 of the vehicle-mounted lens should also meet the following conditions:

[0032] The objective lens 43-1 also satisfies: N4≤1.6, V4≥70; wherein N4 is the refractive index of the objective lens 43-1, and V4 is the Abbe number of the objective lens 43-1;

[0033] The objective lens 5 3-2 also satisfies: N5 ≥ 1.7, V5 ≤ 50; wherein N5 is the refractive index of the objective lens 5 3-2, and V5 is the Abbe number of the objective lens 5 3-2;

[0034] The objective lens six positive lenses 3-3a also satisfy: Npositive ≥ 1.7, Vpositive ≤ 50; wherein Npositive is the refractive index of the objective lens six positive lenses 3-3a, and Vpositive is the Abbe number of the objective lens six positive lenses 3-3a; the objective lens six negative lenses 3-3b also satisfy: Nneg ≥ 1.7, Vneg ≤ 50; wherein Npositive is the refractive index of the objective lens six negative lenses 3-3b, and Vpositive is the Abbe number of the objective lens six negative lenses 3-3b;

[0035] The objective lens seven 3-4 also satisfies: N7≥1.7, V7≤50; wherein N7 is the refractive index of the objective lens seven 3-4, and V7 is the Abbe number of the objective lens seven 3-4.

[0036] In this embodiment, the components of the front lens group 1 of the vehicle-mounted lens adopt a coaxial design; the components of the rear lens group 3 adopt a coaxial design; at the same time, the front lens group 1, the aperture 2 and the rear lens group 3 also adopt a coaxial design.

[0037] In this embodiment, the vehicle-mounted lens must also meet the following conditions: 35mm≥TTL≥20mm; wherein the TTL represents the vertical distance from the front lens group 1 to the image plane 5 of the vehicle-mounted lens, that is, the total optical length of the vehicle-mounted lens.

[0038] In this embodiment, the objective lens 2 1-2 and the objective lens 7 3-4 of the vehicle-mounted lens are aspherical lenses, and any aspherical surface satisfies the following formula:

[0039]

[0040] Among them, Z is the height loss of the aspheric surface at the position of the clear aperture radius y along the optical axis, that is, the axial distance from the position of the aperture radius y to the vertex of the aspheric surface; R is the radius of curvature of the central sphere; K is the quadratic surface coefficient; A, B, C, and D are respectively the high-order aspheric surface coefficients.

[0041] The vehicle-mounted lens in this embodiment, the objective lens 1-1 is made of crown material with good chemical properties and strong corrosion resistance, which can improve the adaptability of the vehicle-mounted lens to harsh environments such as sand and salt spray. The objective lens 2-2 and the objective lens 7-4 are made of low-softening molded materials. The objective lens 3-3, the objective lens 4-1, the objective lens 5-2 and the objective lens 6-3-3 are made of glass materials. The all-glass design can reduce image drift and improve the temperature adaptability of the vehicle-mounted lens.

[0042] The filter 4 in this embodiment is located between the rear lens group 3 and the imaging plane 5. The filter 4 is used to control the transmission spectrum width of the light radiation, cut off the non-imaging spectrum, and improve the contrast of the image plane. The imaging wide spectrum enters the filter 4 after passing through the front objective lens 1, the aperture 2, and the rear objective lens 3, and the imaging spectrum coming out of the filter 4 is converged on the image plane 5.

[0043] In one embodiment of the present invention, the radius of curvature r, the center thickness d, the refractive index N and the Abbe number V of each side of the objective lens 1-1, the objective lens 2 1-2, the objective lens 3 1-3, the aperture 2, the objective lens 4 3-1, the objective lens 5 3-2, the objective lens 6 3-3 and the objective lens 7 3-4 satisfy the following table:

[0044]

[0045]

[0046] The front surface S3 and the rear surface S4 of the objective lens 2 1-2, and the front surface S14 and the rear surface S15 of the objective lens 7 3-4 are aspherical surfaces, and their quadratic surface coefficients K, and the higher-order aspherical surface coefficients A, B, C, and D are shown in the following table:

[0047]

[0048]

[0049] In this embodiment, the vehicle-mounted lens that meets the above conditions has a focal length f'=3.6, an F number=1.6, and a total optical length TTL from the front lens group to the image plane=30 mm.

[0050] The optical performance simulation of the vehicle-mounted lens in this embodiment is performed, and its modulation transfer function characteristic curve is as follows: Figure 2 The distortion characteristic curve is shown as Figure 3 As shown, the vertical axis chromatic aberration curve is as follows Figure 4 As shown, the axial chromatic aberration curve is as follows Figure 5 As shown, the relative illumination curve is Figure 6 shown.

[0051] Figure 2 It is the optical transfer function curve of the vehicle-mounted lens in this embodiment. The horizontal axis is the spatial frequency, the unit is lp / mm, and the vertical axis is the modulation degree between the image point and the object point. Curve F1: Diff.Limit is the diffraction limit of the vehicle-mounted lens, which is also the limiting resolution. The transfer function curve corresponding to the on-axis light when the field of view angle is 0° is F1, and F2, F3, F4, F5, and F6 are the transfer function curves corresponding to the off-axis field of view. The field of view angle corresponding to F2 is 30°, the field of view angle corresponding to F3 is 36°, the field of view angle corresponding to F4 is 50°, the field of view angle corresponding to F5 is 50°, and the field of view angle corresponding to F6 is 61.7°. From Figure 2 It can be seen that at a spatial frequency of 85lp / mm, the diffraction limit of the optical transfer function in this embodiment is close to 0.9, the optical transfer function of the on-axis field of view is greater than 0.8, the optical transfer function of the maximum field of view is greater than 0.73, and the optical transfer function of the full field of view is between 0.73 and 0.8, which is close to the diffraction limit.

[0052] Figure 3 : is the optical distortion curve of the vehicle-mounted lens in this embodiment. The optical distortion value of the maximum field of view is -0.44, which meets the distortion requirement of a large field of view.

[0053] Figure 4 : is the axial chromatic aberration curve of the vehicle-mounted lens in this embodiment, the abscissa is the axial spherical aberration, the unit is mm, the ordinate is the aperture, and 1 represents the normalized maximum aperture. Figure 4 The c curve in the middle represents the spherical aberration of the light with a wavelength of 470nm in the vehicle lens, the d curve represents the spherical aberration of the light with a wavelength of 550nm in the vehicle lens, and the e curve represents the spherical aberration of the light with a wavelength of 670nm in the vehicle lens. The spherical aberration of the three spectra is consistent in the full aperture range and is well controlled. The axial chromatic aberration is the difference in spherical aberration, and the axial chromatic aberration is ultimately less than 0.013mm.

[0054] Figure 5 : is the vertical axis chromatic aberration curve of the vehicle-mounted lens in this embodiment, the abscissa is the vertical axis chromatic spherical aberration, the unit is mm, the ordinate is the aperture, and 1 represents the normalized maximum aperture. Figure 5Curve a in the figure is the vertical chromatic aberration between wavelengths 470nm and 670nm, and curve b is the vertical chromatic aberration between wavelengths 470nm and 550nm. The distance between curve a and curve b at the same aperture is the vertical chromatic aberration between wavelengths 550nm and 67nm. As can be seen from curve 4, the final axial chromatic aberration is less than 0.006mm.

[0055] Figure 6 : is the relative illumination curve of the vehicle-mounted lens in this embodiment, the horizontal axis is the field of view angle, and the vertical axis is the relative illumination. The relative illumination is used to evaluate the uniformity of the image brightness, which is the ratio of the off-axis field of view to the on-axis field of view. The relative illumination of the vehicle-mounted lens in this embodiment is 73% when the maximum field of view is 61.7°.

[0056] Compared with the technology in 201810771948.5, the focal length of the present invention is increased, but the F number is reduced, so its resolution and relative illumination are greatly improved; in addition, compared with the technology in 200920122166.5, although the F number is equivalent, its field of view is increased, which expands the imaging range and usage environment. This embodiment provides a vehicle lens with clear images, good image contrast, and suitable for 8MP chip high-definition imaging.

[0057] It can be seen from the above technical scheme that the vehicle-mounted lens optical system of the present invention adopts a combination of spherical and aspherical surfaces, has large aperture imaging performance, and provides a special form of chromatic aberration and distortion for the lens, ensuring the image plane illumination within the horizontal 120° field of view. While the resolution capability of the entire set of lenses is improved, the length and aperture of the lens are also effectively controlled, and large target surface imaging is achieved using a small aperture lens; the expansion coefficient and stability of the material and other properties are taken into consideration during the design process, and the athermal design concept is introduced. Through the matching of optical materials and structural materials, the athermal design of the optical machine is realized, ensuring the imaging quality of the system within the temperature difference range of -40°C to 115°C, effectively reducing the problems of image plane offset and image quality degradation, and can meet the needs of different usage environments.

[0058] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An automotive lens optical system suitable for an 8MP chip, characterized in that: The invention comprises: a front lens group (1), an aperture (2), a rear lens group (3), a filter (4) and an imaging surface (5) which are coaxially arranged from the front object side to the rear image side; the front lens group (1) has a negative focal length; the rear lens group (3) has a positive focal length; the aperture (2) is located between the front lens group (1) and the rear lens group (3), and the center of the aperture of the aperture (2) is located on the optical axis; the imaging surface (5) is located on the rear side of the rear lens group (3), and the filter (4) is located between the rear lens group (3) and the imaging surface (5); the ratio of the combined focal length Fa of the front lens group (1) to the combined focal length Fb of the rear lens group (3) satisfies -2≥Fa / Fb≥-23; wherein Fa is the combined focal length value of the front lens group (1), and Fb is the combined focal length value of the rear lens group (3); The front lens group (1) comprises, from the object side to the image side, an objective lens 1 (1-1), an objective lens 2 (1-2) and an objective lens 3 (1-3); the objective lens 1 (1-1) has a negative focal length, and the front surface of the objective lens 1 is a convex surface; the objective lens 2 (1-2) has a negative focal length, and the front surface of the objective lens 2 is a concave surface; the objective lens 3 (1-3) has a positive focal length; The objective lens 1 (1-1) further satisfies: N1≥1.7, V1≤50; wherein N1 is the refractive index of the objective lens 1 (1-1), and V1 is the Abbe number of the objective lens 1 (1-1); the objective lens 2 (1-2) further satisfies: N2≥1.7, V2≤50; wherein N2 is the refractive index of the objective lens 2 (1-2), and V2 is the Abbe number of the objective lens 2 (1-2); the objective lens 3 (1-3) further satisfies: N3≥1.7, V3≤50; wherein N3 is the refractive index of the objective lens 3 (1-3), and V3 is the Abbe number of the objective lens 3 (1-3); The rear lens group (3) includes, from the object side to the image side, an objective lens four (3-1), an objective lens five (3-2), an objective lens six (3-3) and an objective lens seven (3-4); the objective lens four (3-1) has positive focal power and is a meniscus lens, and the rear surface of the objective lens four is a convex surface; the objective lens five (3-2) has positive focal power and is a double convex lens; the objective lens six (3-3) has negative focal power and is a cemented lens, which is composed of the objective lens six positive lens (3-3a) and the objective lens six negative lens (3-3b) cemented together; the objective lens six positive lens (3-3a) has positive focal power and is a double convex lens; the objective lens six negative lens (3-3b) has negative focal power and is a double concave lens; the objective lens seven (3-4) has positive focal power and is a meniscus lens, and the front surface of the objective lens seven is a convex surface; The objective lens 4 (3-1) further satisfies: N4≤1.6, V4≥70; wherein N4 is the refractive index of the objective lens 4 (3-1), and V4 is the Abbe number of the objective lens 4 (3-1); the objective lens 5 (3-2) further satisfies: N5≥1.7, V5≤50; wherein N5 is the refractive index of the objective lens 5 (3-2), and V5 is the Abbe number of the objective lens 5 (3-2); the objective lens six positive lens (3-3a) further satisfies: Npositive≥1.7, Vpositive≤50; wherein Npositive is the refractive index of the objective lens six positive lens The refractive index of the objective lens (3-3a) is V positive, and the Abbe number of the objective lens six positive lenses (3-3a) is V positive; the objective lens six negative lenses (3-3b) also satisfy: N negative ≥ 1.7, V negative ≤ 50; wherein N positive is the refractive index of the objective lens six negative lenses (3-3b), and V positive is the Abbe number of the objective lens six negative lenses (3-3b); the objective lens seven (3-4) also satisfies: N7 ≥ 1.7, V7 ≤ 50; wherein N7 is the refractive index of the objective lens seven (3-4), and V7 is the Abbe number of the objective lens seven (3-4); The vehicle-mounted lens optical system satisfies: 35mm≥TTL≥20mm; wherein TTL represents the vertical distance from the front lens group (1) to the image plane (5), that is, the total optical length of the vehicle-mounted lens; The objective lens 2 (1-2) and the objective lens 7 (3-4) of the vehicle-mounted lens are aspherical lenses, and any aspherical surface satisfies the following formula: Among them, Z is the height loss of the aspheric surface at the position of the clear aperture radius y along the optical axis, that is, the axial distance from the position of the aperture radius y to the vertex of the aspheric surface; R is the radius of curvature of the central sphere; K is the quadratic surface coefficient; A, B, C, and D are respectively the high-order aspheric surface coefficients; The objective lens 1 (1-1) is made of a crown material, the objective lens 2 (1-2) and the objective lens 7 (3-4) are made of a low-softening molded material, and the objective lens 3 (1-3), the objective lens 4 (3-1), the objective lens 5 (3-2) and the objective lens 6 (3-3) are made of a glass material; The curvature radius r, center thickness d, refractive index N and Abbe number V of each side of the objective lens 1 (1-1), objective lens 2 (1-2), objective lens 3 (1-3), aperture (2), objective lens 4 (3-1), objective lens 5 (3-2), objective lens 6 (3-3) and objective lens 7 (3-4) meet the following table: Among them, in the front lens group 1 and the rear lens group 3, the front surface and the rear surface of each lens are respectively expressed by the front surface S1 of objective lens 1, the rear surface S2 of objective lens 1, the front surface S3 of objective lens 2, the rear surface S4 of objective lens 2, the front surface S5 of objective lens 3, the rear surface S6 of objective lens 3, the front surface S7 of objective lens 4, the rear surface S8 of objective lens 4, the front surface S9 of objective lens 5, the rear surface S10 of objective lens 5, the front surface S11 of objective lens 6, the bonding surface S12 of objective lens 6, the rear surface S13 of objective lens 6, the front surface S14 of objective lens 7, and the rear surface S15 of objective lens 7; The front surface S3 and the rear surface S4 of the objective lens 2 (1-2), and the front surface S14 and the rear surface S15 of the objective lens 7 (3-4) are aspherical surfaces, and their quadratic surface coefficients K, and high-order aspherical surface coefficients A, B, C, and D are shown in the following table: 。

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