Driving assistance optical lens and imaging method thereof

Abstract

The application relates to a driving assistance optical lens, and the lens optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in sequence from left to right along the light path of light incidence; a diaphragm is arranged between the fourth lens and the fifth lens; without considering the reverse bending caused by the aspherical surface coefficient, the first lens is a meniscus negative lens, the object side surface of which is a convex surface, and the image side surface is a concave surface; the second lens is a double-concave negative lens; the third lens is a double-convex positive lens; the fourth lens is a positive lens, the object side surface of which is a convex surface; the fifth lens is a positive lens, the object side surface of which is a convex surface; the sixth lens is a double-convex positive lens; the seventh lens is a negative lens, the object side surface of which is a concave surface; and the eighth lens is a meniscus negative lens, the object side surface of which is a concave surface, and the image side surface is a convex surface. Through optimization of the curvature radius, center thickness, air gap and material ratio of each lens, a large-aperture light transmission design is matched, and the light transmission amount of the system is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of lens technology, specifically to a driving assistance optical lens and its imaging method, and more particularly to a driving assistance lens with a large aperture, large target area, and high resolution. Background Technology

[0002] With the gradual popularization of L2+ level and above autonomous driving, vehicles need to simultaneously perform close-range detection during low-speed parking and recognition of mid-to-long-range targets in blind spots during driving. Currently, automotive perception lenses are divided into two main categories: side-view lenses and surround-view fisheye lenses. These two types are used independently and cannot meet the needs of multiple operating conditions. Traditional side-view lenses have a small field of view, making it difficult to cover the close-range areas around the vehicle; conventional surround-view fisheye lenses have an excessively large field of view, making distortion difficult to control, resulting in rapid degradation of edge image quality and insufficient long-range target recognition capabilities. At the same time, existing automotive lenses of this type generally have limited aperture sizes, resulting in insufficient light intake in low-light environments and poor signal-to-noise ratios in nighttime and tunnel scenes; most products are adapted to small-area image sensors, limiting the imaging area and making it difficult to integrate high-pixel chips, leading to poor overall resolution consistency. Currently, there is a lack of medium-field-of-view automotive optical lenses that simultaneously possess large aperture, large-area adaptability, and high resolution across the entire field of view, making it impossible to meet the dual needs of close-range parking perception and long-range detection of obstacles and lane lines on the side of the vehicle using a single type of lens.

[0003] Therefore, there is an urgent need to design an automotive lens with optimized optical parameters to balance the field of view, distortion level, light transmission capability and full field of view resolution performance, so as to realize integrated sensing applications around the perimeter. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a driving assistance optical lens and its imaging method, wherein the lens has a large aperture, a large target surface and high resolution, so as to realize the integrated perception application of the surrounding side.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is: a driving assistance optical lens, wherein the optical system of the lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from left to right along the incident light path, and an aperture stop is provided between the fourth lens and the fifth lens; without considering the curvature caused by the aspherical coefficient, the first lens is a meniscus negative lens, with its object side being convex and its image side being concave; the second lens is a biconcave negative lens; the third lens is a biconvex positive lens; and the fourth lens is a positive lens, whose... The object-side surface of the fifth lens is convex; the object-side surface of the sixth lens is convex; the object-side surface of the seventh lens is concave; the object-side surface of the eighth lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface. All lenses are made of glass. Among them, the fifth and eighth lenses are aspherical glass lenses, the second and third lenses are cemented lens groups, and the sixth and seventh lenses are cemented lens groups. The image-side surface of the fourth lens can be either convex or concave; the image-side surface of the fifth lens can be either convex or concave; and the image-side surface of the seventh lens can be either convex or concave.

[0006] Preferably, the focal length of the optical system is set to F, satisfying 4.0mm < F < 6.0mm; the focal lengths of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens are F1, F2, F3, F4, F5, F6, F7, and F8, respectively; the focal length of the cemented lens group composed of the second and third lenses is F23; and the focal length of the cemented lens group composed of the sixth and seventh lenses is F67; wherein F23, F67, and F satisfy the following relationship: -2 < |F23 / F| < 10, |(1 / F23+1 / F67)·F| < 0.4; and F5 and F8 satisfy the following relationship: |F8 / F5| > 5.

[0007] Preferably, the first lens satisfies the relationship: 1.4 ≤ ≤1.7, ≥50.0; The second lens satisfies the relationship: 1.5≤ ≤1.8, ≤50.0; The third lens satisfies the relationship: 1.5≤ ≤1.8, ≥40.0; The fourth lens satisfies the relationship: 1.5≤ ≤1.8, ≤50.0; The fifth lens satisfies the relationship: 1.2≤ ≤1.6, ≥50.0; The sixth lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; The seventh lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; The eighth lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; where For refractive index, It is an Abbe number.

[0008] Preferably, the refractive index N of the second lens d2 Abbe number V d2 The refractive index N of the third lens d3 Abbe number V d3 Satisfies the relation: 0 < |(V) d2 -V d3 )·(N d2 -N d3 | < 3; The refractive index N of the sixth lens d6 Abbe number V d6 The refractive index N of the seventh lens d7 Abbe number V d7 Satisfies the relation: 10 < |(V d6 -V d7 )·(N d6 -N d7 )|<25.

[0009] Preferably, the on-axis distances between the lenses satisfy the following relationships: the air gap between the first lens and the second lens is 3.0~5.0mm; the air gap between the second lens and the third lens is 0mm as a cemented lens group; the air gap between the third lens and the fourth lens is 0.1~1.0mm; the air gap between the fourth lens and the aperture stop is 1.0~4.0mm; the air gap between the aperture stop and the fifth lens is -1.0~1.0mm; the air gap between the fifth lens and the sixth lens is 0.1~2.0mm; the air gap between the sixth lens and the seventh lens is 0mm as a cemented lens group; and the air gap between the seventh lens and the eighth lens is 1.0~5.0mm.

[0010] Preferably, the equations for the aspherical curves of the fifth and eighth lenses are as follows:

[0011]

[0012] Where z is the distance from the vertex of the aspherical surface to the optical axis at a position of height h; c is the paraxial curvature of the aspherical surface; and k is the conic constant. , , , , , , , All are coefficients of higher-order terms; r = 1 / c.

[0013] Preferably, the aperture number FNO of the optical system satisfies 1.4≤FNO≤2.0.

[0014] Preferably, the maximum field of view (FOV) of the optical system satisfies 38° < FOV < 52°.

[0015] Preferably, the total optical length TTL of the optical system satisfies the following relationship with the focal length F and the number of apertures FNO of the optical system: 7 < TTL·FNO / F < 10; the image height IH of the optical system satisfies the following relationship with the focal length F and the total optical length TTL of the optical system: (TTL-IH) / FNO > 14.

[0016] An imaging method for a driving assistance optical lens comprises the following steps: the optical system of the camera sequentially passes through a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, and an eighth lens to form an image.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The driving assistance optical lens provided by this invention employs eight optical lenses, consisting of two glass aspherical lenses and six glass spherical lenses forming the imaging system. By optimizing the curvature radius, center thickness, air gap, and material ratio of each lens, and matching a large aperture light-gathering design, the system's light intake is effectively improved. Simultaneously, the optimized lens optical system adapts to large-size imaging targets, is compatible with high-pixel image sensors, and fully leverages the advantages of large-scale imaging. Furthermore, the all-glass lens material adapts to different temperature usage scenarios for automotive lenses, resulting in more stable imaging performance.

[0019] 2. This lens adopts a moderate horizontal field of view of about 85°, which eliminates the serious distortion defects caused by the ultra-large field of view of traditional fisheye lenses. By optimizing and balancing spherical aberration, coma, chromatic aberration and field curvature through high-order aberration optimization, it significantly suppresses optical distortion across the entire field of view and ensures that the image deformation is controllable. At the same time, the modulation transfer function of the lens across the entire field of view is optimized in the whole domain, so that the lens maintains high resolution from the center field of view to the edge field of view, and achieves high-resolution uniform imaging across the entire field of view.

[0020] 3. Through precise matching of optical structures, this invention achieves a multi-dimensional balance of field of view coverage, distortion control, light transmission capability, and resolution performance while ensuring large aperture and large target surface imaging specifications. This allows a single lens to be adapted to dual application scenarios of close-range panoramic imaging for low-speed vehicle parking and mid-to-long-range target recognition for high-speed driving.

[0021] 4. Two sets of cemented lens groups are used to constrain relative optical power and total optical power to balance chromatic aberration and distortion, and control curvature and mass production tolerance sensitivity; the cementation constrains the product of refractive index and Abbe number to ensure chromatic aberration capability, while also taking into account the environmental stability of automotive glass materials.

[0022] 5. Two aspherical glass elements are used. By controlling the combined optical power of the two aspherical glass elements and combining the constraints of total length, aperture, and focal length, aberration correction and overall vehicle size are taken into account.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the optical structure of Embodiment 1 of the present invention;

[0025] Figure 2 This is the axial chromatic aberration diagram of the entire working band of Embodiment 1 of the present invention;

[0026] Figure 3 This is the transverse chromatic aberration diagram of the entire working band of Embodiment 1 of the present invention;

[0027] Figure 4 This is the field curvature distortion diagram of the entire working band of Embodiment 1 of the present invention;

[0028] Figure 5 This is a schematic diagram of the optical structure of Embodiment 2 of the present invention;

[0029] Figure 6 This is the axial chromatic aberration diagram of the entire working band of Embodiment 2 of the present invention;

[0030] Figure 7 This is the transverse chromatic aberration diagram of the entire working band of Embodiment 2 of the present invention;

[0031] Figure 8 This is the field curvature distortion diagram of the entire working band of Embodiment 2 of the present invention;

[0032] Figure 9 This is a schematic diagram of the optical structure of Embodiment 3 of the present invention;

[0033] Figure 10 This is the axial chromatic aberration diagram of the entire working band of Embodiment 3 of the present invention;

[0034] Figure 11 This is the transverse chromatic aberration diagram of the entire working band of Embodiment 3 of the present invention;

[0035] Figure 12 This is the field curvature distortion diagram of the entire working band of Embodiment 3 of the present invention;

[0036] In the diagram: STO - aperture stop; L1 - first lens; L2 - second lens; L3 - third lens; L4 - fourth lens; L5 - fifth lens; L6 - sixth lens; L7 - seventh lens; L8 - eighth lens; L9 - equivalent glass plate; IMA - imaging plane. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0040] like Figures 1-12 As shown, this embodiment provides a driving assistance optical lens. The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from left to right along the incident light path. An aperture stop is provided between the fourth and fifth lenses. Ignoring the curvature caused by aspherical coefficients, the first lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the second lens is a biconcave negative lens; the third lens is a biconvex positive lens; and the fourth lens is a positive lens with a convex object-side surface. The fifth lens is a positive lens with a convex object-side surface; the sixth lens is a biconvex positive lens; the seventh lens is a negative lens with a concave object-side surface; the eighth lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface; all lenses are made of glass, among which the fifth and eighth lenses are aspherical glass lenses, the second and third lenses are cemented lens groups, and the sixth and seventh lenses are cemented lens groups; the image-side surface of the fourth lens can be either convex or concave; the image-side surface of the fifth lens can be either convex or concave; the image-side surface of the seventh lens can be either convex or concave.

[0041] In this embodiment of the invention, the focal length of the optical system is set to F, satisfying 4.0mm < F < 6.0mm; the focal lengths of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens are F1, F2, F3, F4, F5, F6, F7, and F8, respectively; the focal length of the cemented lens group composed of the second and third lenses is F23; and the focal length of the cemented lens group composed of the sixth and seventh lenses is F67; wherein F23, F67, and F satisfy the following relationship: -2 < |F23 / F| < 10, |(1 / F23+1 / F67)·F| < 0.4; and F5 and F8 satisfy the following relationship: |F8 / F5| > 5.

[0042] In this embodiment of the invention, the first lens satisfies the relationship: 1.4 ≤ ≤1.7, ≥50.0; The second lens satisfies the relationship: 1.5≤ ≤1.8, ≤50.0; The third lens satisfies the relationship: 1.5≤ ≤1.8, ≥40.0; The fourth lens satisfies the relationship: 1.5≤ ≤1.8, ≤50.0; The fifth lens satisfies the relationship: 1.2≤ ≤1.6, ≥50.0; The sixth lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; The seventh lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; The eighth lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; where For refractive index, It is an Abbe number.

[0043] In this embodiment of the invention, the refractive index N of the second lens d2 Abbe number V d2 The refractive index N of the third lens d3 Abbe number V d3 Satisfies the relation: 0 < |(V) d2 -V d3 )·(N d2 -N d3 | < 3; The refractive index N of the sixth lens d6 Abbe number V d6 The refractive index N of the seventh lens d7 Abbe number V d7 Satisfies the relation: 10 < |(Vd6 -V d7 )·(N d6 -N d7 )|<25.

[0044] In this embodiment of the invention, the on-axis distances between the lenses satisfy the following relationships: the air gap between the first lens and the second lens is 3.0~5.0mm; the second lens and the third lens are a cemented lens group with an air gap of 0mm; the air gap between the third lens and the fourth lens is 0.1~1.0mm; the air gap between the fourth lens and the aperture stop is 1.0~4.0mm; the air gap between the aperture stop and the fifth lens is -1.0~1.0mm; the air gap between the fifth lens and the sixth lens is 0.1~2.0mm; the sixth lens and the seventh lens are a cemented lens group with an air gap of 0mm; and the air gap between the seventh lens and the eighth lens is 1.0~5.0mm.

[0045] In this embodiment of the invention, the equations for the aspherical curves of the fifth and eighth lenses are as follows:

[0046]

[0047] Where z is the distance from the vertex of the aspherical surface to the optical axis at a position of height h; c is the paraxial curvature of the aspherical surface; and k is the conic constant. , , , , , , , All are coefficients of higher-order terms; r = 1 / c.

[0048] In this embodiment of the invention, the aperture number FNO of the optical system satisfies 1.4≤FNO≤2.0.

[0049] In this embodiment of the invention, the maximum field of view (FOV) of the optical system satisfies 38° < FOV < 52°.

[0050] In this embodiment of the invention, the total optical length TTL of the optical system satisfies the following relationship with the focal length F and the number of apertures FNO of the optical system: 7 < TTL·FNO / F < 10; the image height IH of the optical system satisfies the following relationship with the focal length F and the total optical length TTL of the optical system: (TTL-IH) / FNO > 14.

[0051] An imaging method for a driving assistance optical lens comprises the following steps: the optical system of the camera sequentially passes through a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, and an eighth lens to form an image.

[0052] Specific implementation process:

[0053] Example 1

[0054] like Figure 1 As shown, a driving assistance optical lens is provided. The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from left to right along the incident light path. An aperture stop is disposed between the fourth lens and the fifth lens. All the lenses are made of glass material, wherein the fifth and eighth lenses are aspherical glass lenses.

[0055] Without considering the curvature caused by aspherical coefficients, the first lens is a meniscus negative lens with a convex object side and a concave image side; the second lens is a biconcave negative lens; the third lens is a biconvex positive lens; the fourth lens is a meniscus positive lens with a convex object side and a concave image side; the fifth lens is a meniscus positive lens with a convex object side and a concave image side; the sixth lens is a biconvex positive lens; the seventh lens is a meniscus negative lens with a concave object side and a convex image side; and the eighth lens is a meniscus negative lens with a concave object side and a convex image side. All lenses are made of glass, with the fifth and eighth lenses being aspherical glass lenses, the second and third lenses being cemented lens groups, and the sixth and seventh lenses being cemented lens groups.

[0056] The first lens features a meniscus shape convex towards the object side, allowing it to receive incident light across a wide field of view and guide it to the rear optical system. Its convex shape also facilitates the sliding off of water droplets, reducing the interference of rain and snow on imaging. The second and third lenses form a cemented doublet optical assembly. Their bonding helps to cancel and balance distortions generated by the system, reducing the sensitivity of the overall optical performance to assembly tolerances. Both the second and third lenses are made of glass, significantly improving the environmental stability and durability of the lens assembly, making it suitable for complex automotive applications. The fourth lens is a single glass lens that compensates for spherical and coma aberrations, shares the burden of aberration correction with the front group, optimizes central field-of-view resolution, and smooths out aberration variations across the entire field of view. The aperture stop is positioned between the fourth and fifth lenses. This central placement of the aperture stop promotes a high degree of balance between the front and rear groups of light, and helps to reduce the aperture and overall length of the optical system. The fifth lens compresses light, allowing it to enter the aperture smoothly, which is beneficial for increasing the aperture diameter and the system's light transmission. Simultaneously, the fifth lens uses an aspherical glass surface, whose shape is less affected by temperature. The aspherical surface helps suppress advanced spherical aberration, field curvature, and residual distortion, significantly improving edge field-of-view resolution and enhancing edge imaging quality in a large field of view. The sixth and seventh lenses form a rear-end cemented doublet assembly to eliminate residual chromatic aberration, correct field curvature and astigmatism, and make the focal plane flatter, improving the uniformity of global imaging resolution. The cemented structure has strong tolerance adaptability, and material combinations can improve the overall thermal performance. The eighth lens is an image-side aspherical glass surface, completing the final correction of residual distortion and astigmatism, optimizing the MTF performance across the entire field of view, and adapting to the high-resolution imaging requirements of large target surfaces. The aspherical glass surface has excellent shape stability and can withstand image quality degradation caused by high and low temperatures and vibrations in automotive environments. The well-matched lenses enable the optical system to achieve a design with a large aperture, large target surface, small size, and low temperature drift. Simultaneously, it effectively corrects on-axis and off-axis aberrations, resulting in good image quality. Figures 2 to 4 As shown.

[0057] The technical specifications achieved by the optical system in this embodiment are as follows:

[0058] (1) Focal length: 4.0≤F≤6.0mm;

[0059] (2) Aperture FNO≤2.0;

[0060] (3) Half field of view: 38°≤FOV≤52°;

[0061] (4) Operating band: Visible light band.

[0062] To achieve the above design parameters, the specific design of the optical system adopted in this embodiment is shown in the table below:

[0063]

[0064] The aspherical coefficients of the aspherical lenses in the optical system of this embodiment are shown in the table below:

[0065] The optical system in this embodiment optimizes the curvature radius, center thickness, air gap, and material ratio of each lens, and matches a large aperture light-gathering design to effectively increase the amount of light entering the system. At the same time, the optimized lens optical system is adapted to large-size imaging targets and compatible with high-pixel image sensors, giving full play to the advantages of large-scale imaging. In addition, the all-glass material of the lenses is adapted to the different temperature usage scenarios of automotive lenses, resulting in more stable imaging effects.

[0066] Example 2

[0067] like Figure 5 As shown, a driving assistance optical lens is provided. The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from left to right along the incident light path. An aperture stop is disposed between the fourth lens and the fifth lens. All the lenses are made of glass material, wherein the fifth and eighth lenses are aspherical glass lenses.

[0068] Without considering the curvature caused by aspherical coefficients, the first lens is a meniscus negative lens with a convex object side and a concave image side; the second lens is a biconcave negative lens; the third lens is a biconvex positive lens; the fourth lens is a meniscus positive lens with a convex object side and a concave image side; the fifth lens is a biconvex positive lens; the sixth lens is a biconvex positive lens; the seventh lens is a meniscus negative lens with a concave object side and a convex image side; and the eighth lens is a meniscus negative lens with a concave object side and a convex image side. All lenses are made of glass, with the fifth and eighth lenses being aspherical glass lenses, the second and third lenses being cemented lens groups, and the sixth and seventh lenses being cemented lens groups.

[0069] The first lens features a meniscus shape convex towards the object side, allowing it to receive incident light across a wide field of view and guide it to the rear optical system. Its convex shape also facilitates the sliding off of water droplets, reducing the interference of rain and snow on imaging. The second and third lenses form a cemented doublet optical assembly. Their bonding helps to cancel and balance distortions generated by the system, reducing the sensitivity of the overall optical performance to assembly tolerances. Both the second and third lenses are made of glass, significantly improving the environmental stability and durability of the lens assembly, making it suitable for complex automotive applications. The fourth lens is a single glass lens that compensates for spherical and coma aberrations, shares the burden of aberration correction with the front group, optimizes central field-of-view resolution, and smooths out aberration variations across the entire field of view. The aperture stop is positioned between the fourth and fifth lenses. This central placement of the aperture stop promotes a high degree of balance between the front and rear groups of light, and helps to reduce the aperture and overall length of the optical system. The fifth lens compresses light, allowing it to enter the aperture smoothly, which is beneficial for increasing the aperture diameter and the system's light transmission. Simultaneously, the fifth lens uses a glass aspherical surface, whose shape is less affected by temperature. The aspherical surface helps suppress advanced spherical aberration, field curvature, and residual distortion, significantly improving edge field-of-view resolution and enhancing edge imaging quality in a large field of view. The sixth and seventh lenses form a rear-end cemented doublet assembly to eliminate residual chromatic aberration, correct field curvature and astigmatism, and make the focal plane flatter, improving the uniformity of global imaging resolution. The cemented structure has strong tolerance adaptability, and material combinations can improve the overall thermal performance. The eighth lens is an image-side glass aspherical surface, completing the final correction of residual distortion and astigmatism, optimizing the MTF performance across the entire field of view, and adapting to the high-resolution imaging requirements of large target surfaces. The glass aspherical surface has excellent shape stability and can withstand image quality degradation caused by high and low temperatures and vibrations in automotive environments. The well-matched lenses enable the optical system to achieve a design with a large aperture, large target surface, small size, and low temperature drift. Simultaneously, it effectively corrects on-axis and off-axis aberrations, resulting in good image quality. Figures 6 to 8 As shown.

[0070] The technical specifications achieved by the optical system in this embodiment are as follows:

[0071] (1) Focal length: 4.0≤F≤6.0mm;

[0072] (2) Aperture FNO≤2.0;

[0073] (3) Half field of view: 38°≤FOV≤52°;

[0074] (4) Operating band: Visible light band.

[0075] To achieve the above design parameters, the specific design of the optical system adopted in this embodiment is shown in the table below:

[0076]

[0077] The aspherical coefficients of the aspherical lenses in the optical system of this embodiment are shown in the table below:

[0078] The optical system in this embodiment optimizes the curvature radius, center thickness, air gap, and material ratio of each lens, and matches a large aperture light-gathering design to effectively increase the amount of light entering the system. At the same time, the optimized lens optical system is adapted to large-size imaging targets and compatible with high-pixel image sensors, giving full play to the advantages of large-scale imaging. In addition, the all-glass material of the lenses is adapted to the different temperature usage scenarios of automotive lenses, resulting in more stable imaging effects.

[0079] Example 3

[0080] like Figure 9 As shown, a driving assistance optical lens is provided. The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from left to right along the incident light path. An aperture stop is disposed between the fourth lens and the fifth lens. All the lenses are made of glass material, wherein the fifth and eighth lenses are aspherical glass lenses.

[0081] Without considering the curvature caused by the aspherical coefficient, the first lens is a meniscus negative lens with a convex object side and a concave image side; the second lens is a biconcave negative lens; the third lens is a biconvex positive lens; the fourth lens is a biconvex positive lens; the fifth lens is a biconvex positive lens; the sixth lens is a biconvex positive lens; the seventh lens is a biconcave negative lens; and the eighth lens is a meniscus negative lens with a concave object side and a convex image side. All lenses are made of glass, with the fifth and eighth lenses being aspherical glass lenses, the second and third lenses being cemented lens groups, and the sixth and seventh lenses being cemented lens groups.

[0082] The first lens features a meniscus shape convex towards the object side, allowing it to receive incident light across a wide field of view and guide it to the rear optical system. Its convex shape also facilitates the sliding off of water droplets, reducing the interference of rain and snow on imaging. The second and third lenses form a cemented doublet optical assembly. Their bonding helps to cancel and balance distortions generated by the system, reducing the sensitivity of the overall optical performance to assembly tolerances. Both the second and third lenses are made of glass, significantly improving the environmental stability and durability of the lens assembly, making it suitable for complex automotive applications. The fourth lens is a single glass lens that compensates for spherical and coma aberrations, shares the burden of aberration correction with the front group, optimizes central field-of-view resolution, and smooths out aberration variations across the entire field of view. The aperture stop is positioned between the fourth and fifth lenses. This central placement of the aperture stop promotes a high degree of balance between the front and rear groups of light, and helps to reduce the aperture and overall length of the optical system. The fifth lens compresses light, allowing it to enter the aperture smoothly, which is beneficial for increasing the aperture diameter and the system's light transmission. Simultaneously, the fifth lens uses a glass aspherical surface, whose shape is less affected by temperature. The aspherical surface helps suppress advanced spherical aberration, field curvature, and residual distortion, significantly improving edge field-of-view resolution and enhancing edge imaging quality in a large field of view. The sixth and seventh lenses form a rear-end cemented doublet assembly to eliminate residual chromatic aberration, correct field curvature and astigmatism, and make the focal plane flatter, improving the uniformity of global imaging resolution. The cemented structure has strong tolerance adaptability, and material combinations can improve the overall thermal performance. The eighth lens is an image-side glass aspherical surface, completing the final correction of residual distortion and astigmatism, optimizing the MTF performance across the entire field of view, and adapting to the high-resolution imaging requirements of large target surfaces. The glass aspherical surface has excellent shape stability and can withstand image quality degradation caused by high and low temperatures and vibrations in automotive environments. The well-matched lenses enable the optical system to achieve a design with a large aperture, large target surface, small size, and low temperature drift. Simultaneously, it effectively corrects on-axis and off-axis aberrations, resulting in good image quality. Figures 10 to 12 As shown.

[0083] The technical specifications achieved by the optical system in this embodiment are as follows:

[0084] (1) Focal length: 4.0≤F≤6.0mm;

[0085] (2) Aperture FNO≤2.0;

[0086] (3) Half field of view: 38°≤FOV≤52°;

[0087] (4) Operating band: Visible light band.

[0088] To achieve the above design parameters, the specific design of the optical system adopted in this embodiment is shown in the table below:

[0089]

[0090] The aspherical coefficients of the aspherical lenses in the optical system of this embodiment are shown in the table below:

[0091] The optical system in this embodiment optimizes the curvature radius, center thickness, air gap, and material ratio of each lens, and matches a large aperture light-gathering design to effectively increase the amount of light entering the system. At the same time, the optimized lens optical system is adapted to large-size imaging targets and compatible with high-pixel image sensors, giving full play to the advantages of large-scale imaging. In addition, the all-glass material of the lenses is adapted to the different temperature usage scenarios of automotive lenses, resulting in more stable imaging effects.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A driving assistance optical lens, characterized in that: The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged sequentially from left to right along the incident light path. An aperture stop is provided between the fourth and fifth lenses. Ignoring the curvature caused by aspherical coefficients, the first lens is a meniscus negative lens with a convex object-side surface and a concave image-side surface; the second lens is a biconcave negative lens; the third lens is a biconvex positive lens; the fourth lens is a positive lens with a convex object-side surface; and the fifth lens is a positive lens. The object-side surface of the fifth lens is convex; the sixth lens is a biconvex positive lens; the seventh lens is a negative lens with a concave object-side surface; the eighth lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface; all lenses are made of glass, among which the fifth and eighth lenses are aspherical glass lenses, the second and third lenses are cemented lens groups, and the sixth and seventh lenses are cemented lens groups; the image-side surface of the fourth lens can be either convex or concave; the image-side surface of the fifth lens can be either convex or concave; the image-side surface of the seventh lens can be either convex or concave.

2. The driving assistance optical lens according to claim 1, characterized in that: The focal length of the optical system is set to F, satisfying 4.0mm < F < 6.0mm; the focal lengths of the first, second, third, fourth, fifth, sixth, seventh, and eighth lenses are F1, F2, F3, F4, F5, F6, F7, and F8, respectively; the focal length of the cemented lens group composed of the second and third lenses is F23; and the focal length of the cemented lens group composed of the sixth and seventh lenses is F67; where F23, F67, and F satisfy the following relationships: -2 < |F23 / F| < 10, |(1 / F23 + 1 / F67)·F| < 0.4; and F5 and F8 satisfy the following relationship: |F8 / F5| > 5.

3. The driving assistance optical lens according to claim 1, characterized in that: The first lens satisfies the relation: 1.4 ≤ ≤1.7, ≥50.0; The second lens satisfies the relationship: 1.5≤ ≤1.8, ≤50.0; The third lens satisfies the relationship: 1.5≤ ≤1.8, ≥40.0; The fourth lens satisfies the relationship: 1.5≤ ≤1.8, ≤50.0; The fifth lens satisfies the relationship: 1.2≤ ≤1.6, ≥50.0; The sixth lens satisfies the relationship: 1.5≤ ≤1.8, ≥50.0; The seventh lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; The eighth lens satisfies the relationship: 1.5≤ ≤2.0, ≤50.0; where For refractive index, It is an Abbe number.

4. The driving assistance optical lens according to claim 3, characterized in that: The refractive index N of the second lens d2 Abbe number V d2 The refractive index N of the third lens d3 Abbe number V d3 Satisfies the relation: 0 < |(V) d2 -V d3 )·(N d2 -N d3 | < 3; The refractive index N of the sixth lens d6 Abbe number V d6 The refractive index N of the seventh lens d7 Abbe number V d7 Satisfies the relation: 10 < |(V d6 -V d7 )·(N d6 -N d7 )|<25.

5. The driving assistance optical lens according to claim 1, characterized in that: The on-axis distances between the lenses satisfy the following relationships: the air gap between the first and second lenses is 3.0~5.0mm; the air gap between the second and third lenses is 0mm (cement lens group); the air gap between the third and fourth lenses is 0.1~1.0mm; the air gap between the fourth lens and the aperture stop is 1.0~4.0mm; the air gap between the aperture stop and the fifth lens is -1.0~1.0mm; the air gap between the fifth and sixth lenses is 0.1~2.0mm; the air gap between the sixth and seventh lenses is 0mm (cement lens group); and the air gap between the seventh and eighth lenses is 1.0~5.0mm.

6. The driving assistance optical lens according to claim 1, characterized in that: The equations for the aspherical curves of the fifth and eighth lenses are as follows: Where z is the distance from the vertex of the aspherical surface to the optical axis at a height of h; c is the paraxial curvature of the aspherical surface; and k is the conic constant. , , , , , , , All are coefficients of higher-order terms; r = 1 / c.

7. The driving assistance optical lens according to claim 1, characterized in that: The aperture number FNO of the optical system satisfies 1.4≤FNO≤2.

0.

8. The driving assistance optical lens according to claim 1, characterized in that: The maximum field of view (FOV) of the optical system satisfies 38° < FOV < 52°.

9. The driving assistance optical lens according to claim 1, characterized in that: The total optical length TTL of the optical system satisfies the following relationship with the focal length F and the number of apertures FNO: 7 < TTL·FNO / F < 10; the image height IH of the optical system satisfies the following relationship with the focal length F and the total optical length TTL: (TTL-IH) / FNO > 14.

10. An imaging method for a driving assistance optical lens as described in any one of claims 1-9, characterized in that, The following steps are performed: the camera's optical system forms an image after passing through the first lens, second lens, third lens, fourth lens, aperture, fifth lens, sixth lens, seventh lens, and eighth lens in sequence.

Images