Large-aperture high-image-quality vehicle-mounted front-view lens and working method thereof

Abstract

The invention relates to a large-aperture high-image-quality vehicle-mounted front-view lens and a working method thereof, and an optical system of the large-aperture high-image-quality vehicle-mounted front-view lens is composed of a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from left to right along a light incident light path. The diaphragm is arranged between the second lens and the third lens. Wherein the first lens is a glass aspheric lens, and the second lens, the third lens, the fourth lens and the fifth lens are glass spherical lenses. By reasonably distributing the focal power and the surface type of each lens, the central thickness of each lens, the on-axis distance between the lenses and the like, the optical system realizes the design of large aperture, high relative illumination, low temperature drift and lower tolerance sensitivity, and meanwhile, on-axis and off-axis aberrations are well corrected, so that the imaging quality is higher.

Description

Technical Field

[0001] This invention relates to the field of lens technology, and in particular to a large-aperture, high-image-quality vehicle-mounted forward-looking lens and its working method. Background Technology

[0002] With the widespread adoption of Advanced Driver Assistance Systems (ADAS) and autonomous driving technologies, the vehicle's forward-facing camera, as a core component for environmental perception, directly impacts the accuracy of a vehicle's recognition of pedestrians, traffic signs, and other targets, thus being crucial for ensuring driving safety. Currently, vehicles need to cope with complex road conditions such as strong sunlight and low-light nighttime conditions, placing higher demands on the image quality and light transmission capabilities of the camera. Simultaneously, the limited installation space in the vehicle's front compartment necessitates a compact camera design. These demands are collectively driving the technological upgrade of vehicle-mounted forward-facing cameras. Summary of the Invention

[0003] In view of the above-mentioned needs of the prior art, the present invention provides a large aperture high image quality vehicle front-view lens and its working method. The large aperture high image quality vehicle front-view lens has a large light-passing aperture and high relative illumination, and has a relatively compact shape structure while achieving high-quality imaging.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: a large-aperture, high-image-quality automotive front-view lens, wherein the optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially from left to right along the incident light path, and an aperture stop is disposed between the second lens and the third lens; without considering the curvature caused by the aspherical coefficient, 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 biconvex positive lens with a convex object-side surface and a convex image-side surface; the third lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; the fourth lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface; and the fifth lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; the lenses are made of glass material, wherein the first lens is a glass aspherical lens, the second, third, fourth, and fifth lenses are spherical lenses, and the third and fourth lenses are a cemented lens group.

[0005] Preferably, the focal length of the optical system is f, and the focal lengths of the first lens, second lens, third lens, fourth lens, and fifth lens are f1, f2, f3, f4, and f5, respectively, wherein f1, f2, f3, f4, and f5 satisfy the following ratio with f: -2.0 <f1 / f<-1.0,1.0<f2 / f<2.0,1.0<f3 / f<2.0,-2.0<f4 / f<-1.0,2.0<f5 / f<3.0。

[0006] Preferably, the first lens satisfies the relationship: 1.6 ≤ N d ≤1.9, Vd ≤50.0; The second lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; The third lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; The fourth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; The fifth lens satisfies the relationship: 1.6≤N d ≤1.9, V d ≥50.0; where N d V is the refractive index. d Let be Abbe's constant.

[0007] Preferably, the on-axis distances between each lens satisfy the following relationships: the air gap between the first lens and the second lens is 4.5 to 5.0 mm; the air gap between the second lens and the aperture stop is 0.0 to 0.5 mm; the air gap between the aperture stop and the third lens is 0.0 to 0.5 mm; the third lens and the fourth lens are a cemented lens group with an air gap of 0 mm; and the air gap between the fourth lens and the fifth lens is 0.5 to 1.0 mm.

[0008] Preferably, the first lens is an aspherical lens. The equation for the aspherical curve is:

[0009]

[0010] Where z is the sag of the aspherical surface at a height of r along the optical axis from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface; k is the conic constant; α1, α2, α3, α4, α5, α6, α7, and α8 are all higher-order coefficients.

[0011] Preferably, the total optical length (TTL) of the optical system and the focal length (f) of the optical system satisfy the following condition: TTL / f ≤ 5.5.

[0012] Preferably, the F-number of the optical system is ≤1.5.

[0013] Preferably, the image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f≥0.5.

[0014] Preferably, the aperture of the optical system is located between the second lens and the third lens.

[0015] Preferably, a filter is provided on the rear side of the fifth lens.

[0016] The technical specifications achieved by the optical system in this embodiment are as follows:

[0017] (1) Focal length: 4.0≤EFFL≤5.0mm;

[0018] (2) Aperture F≤1.5;

[0019] (3) Field of view: 2w ≥ 120°;

[0020] (4) Operating band: Visible light band.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] This invention relates to a large-aperture, high-image-quality automotive forward-looking lens, employing five optical lenses. The imaging system consists of one glass aspherical lens and four glass spherical lenses. The large aperture design increases light intake and provides high relative illumination, enabling high-quality imaging even in low-light, complex road conditions. By rationally combining glass materials, axial chromatic aberration, transverse chromatic aberration, and higher-order chromatic aberrations are corrected, ensuring consistent image quality across the entire field of view. The all-glass lens design minimizes focal plane shift at high and low temperatures, providing adaptability to complex environments. The compact and rational optical structure is easy to assemble, has low tolerance sensitivity, and is suitable for large-scale, high-yield production.

[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 the present invention;

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

[0026] Figure 3 This is the field curvature distortion diagram of the entire working band of the present invention;

[0027] Figure 4 This is the relative illumination map of the entire working band of the present invention;

[0028] In the diagram: STO - aperture stop; L1 - first lens; L2 - second lens; L3 - third lens; L4 - fourth lens; L5 - fifth lens; L6 - first equivalent glass plate; L7 - second equivalent glass plate; IMA - imaging plane. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific implementation methods.

[0030] like Figure 1As shown, the large-aperture, high-image-quality automotive front-view lens of the present invention comprises, from the object side to the image side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, with an aperture stop positioned between the second and third lenses. 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 biconvex positive lens with a convex object side and a convex image side; the third lens is a biconvex positive lens with a convex object side and a convex image side; the fourth lens is a meniscus negative lens with a concave object side and a convex image side; and the fifth lens is a biconvex positive lens with a convex object side and a convex image side. The lenses are made of glass, wherein the first lens is a glass aspherical lens, and the second, third, fourth, and fifth lenses are spherical lenses. The third and fourth lenses form a cemented lens group.

[0031] During operation, the incident light rays pass sequentially through the first lens, the second lens, the aperture stop, the third lens, the fourth lens, the fifth lens, the first equivalent glass plate, and the second equivalent glass plate, before forming an image on the image plane of the second equivalent glass plate.

[0032] Among them, glass aspherical lenses can correct spherical aberration and coma, while reducing the number of lenses used, which is beneficial for compactness and miniaturization; the use of reasonable glass material combinations corrects chromatic aberration and controls temperature drift; by optimizing parameters such as optical power, surface shape, center thickness, and air gap of each lens, the optical system achieves a large aperture, high relative illumination, and low temperature drift design, while also providing good correction for on-axis and off-axis aberrations, resulting in good image quality, such as... Figures 2 to 4 As shown.

[0033] The technical specifications of the optical system achieved by the lens in this application are as follows:

[0034] (5) Focal length: 4.0≤EFFL≤5.0mm;

[0035] (6) Aperture F≤1.5;

[0036] (7) Field of view: 2w ≥ 120°;

[0037] (8) Operating band: Visible light band.

[0038] To achieve the above design parameters, the specific design of the optical system adopted in this embodiment is shown in the table below:

[0039]

[0040] The aspherical coefficients of the aspherical lenses in the optical system of the lens in this application are shown in the table below:

[0041]

[0042] This embodiment achieves large aperture, high relative illumination, and low temperature drift by rationally allocating parameters such as the optical power, surface shape, center thickness, and air gap of each lens. This optical structure effectively corrects on-axis and off-axis aberrations, thereby obtaining excellent image quality.

[0043] 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 large-aperture, high-image-quality vehicle-mounted forward-looking lens, characterized in that: The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially from left to right along the incident light path. An aperture stop is positioned between the second and third 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 biconvex positive lens with a convex object-side surface and a convex image-side surface. The third lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface. The fourth lens is a meniscus negative lens with a concave object-side surface and a convex image-side surface. The fifth lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface. The lenses are made of glass, wherein the first lens is a glass aspherical lens, and the second, third, fourth, and fifth lenses are spherical lenses. The third and fourth lenses form a cemented lens group.

2. The large-aperture, high-image-quality automotive forward-looking lens according to claim 1, characterized in that: The optical system has a focal length of f, and the focal lengths of the first lens, second lens, third lens, fourth lens, and fifth lens are f1, f2, f3, f4, and f5, respectively, wherein f1, f2, f3, f4, and f5 satisfy the following ratio with f: -2.0 <f1 / f<-1.0,1.0<f2 / f<2.0,1.0<f3 / f<2.0,-2.0<f4 / f<-1.0,2.0<f5 / f<3.0。 3. The large-aperture, high-image-quality vehicle-mounted forward-looking lens according to claim 1, characterized in that: The first lens satisfies the following relationship: 1.6 ≤ N d ≤1.9, V d ≤50.0; The second lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; The third lens satisfies the relationship: 1.4≤N d ≤1.7, V d ≥50.0; The fourth lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; The fifth lens satisfies the relationship: 1.6≤N d ≤1.9, V d ≥50.0; where N d V is the refractive index. d Let be Abbe's constant.

4. The large-aperture, high-image-quality automotive forward-looking lens according to claim 1, characterized in that: The on-axis distances between the lenses of the lens satisfy the following relationships: the air gap between the first lens and the second lens is 4.5 to 5.0 mm; the air gap between the second lens and the aperture stop is 0.0 to 0.5 mm; the air gap between the aperture stop and the third lens is 0.0 to 0.5 mm; the third lens and the fourth lens are a cemented lens group with an air gap of 0 mm; and the air gap between the fourth lens and the fifth lens is 0.5 to 1.0 mm.

5. The large-aperture, high-image-quality automotive forward-looking lens according to claim 1, characterized in that: The first lens is an aspherical lens; the equation for the aspherical curve is: Where z is the sag of the aspherical surface at a height of r along the optical axis from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface; k is the conic constant; α1, α2, α3, α4, α5, α6, α7, and α8 are all higher-order coefficients.

6. The large-aperture, high-image-quality automotive forward-looking lens according to claim 1, characterized in that: The total optical length (TTL) of the optical system and the focal length (f) of the optical system satisfy the following conditions: TTL / f ≤ 5.5; the F-number of the optical system ≤ 1.

5.

7. The large-aperture, high-image-quality automotive forward-looking lens according to claim 1, characterized in that: The image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f≥0.

5.

8. The large-aperture, high-image-quality automotive forward-looking lens according to claim 1, characterized in that: The aperture of the optical system is located between the second lens and the third lens.

9. The large-aperture, high-image-quality automotive forward-looking lens according to claim 1, characterized in that: The optical system achieves the following technical specifications: focal length: 4.0 ≤ EFFL ≤ 5.0 mm; aperture F ≤ 1.5; field of view: 2w ≥ 120°; operating wavelength: visible light band; the specific design of the optical system to achieve the above design parameters is shown in the table below: The aspherical coefficients of aspherical lenses are shown in the table below:

10. A method for operating a large-aperture, high-image-quality vehicle-mounted forward-looking lens as described in any one of claims 1-9, characterized in that: The incident light rays pass sequentially through the first lens, the second lens, the aperture stop, the third lens, the fourth lens, the fifth lens, the first equivalent glass plate, and the second equivalent glass plate, and then form an image on the image plane of the second equivalent glass plate.

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