A large aperture six-piece side rear view camera and an imaging method thereof

Abstract

The present application relates to a kind of large aperture six-piece side rear view camera and its imaging method, the optical system of the camera has the lens with optical power along incident light path in sequence is first lens, second lens, third lens, fourth lens, fifth lens and sixth lens, diaphragm is arranged between second lens and third lens, wherein third lens and fourth lens are tightly connected to constitute cemented lens group;First lens is double-concave negative lens, second lens is double-convex positive lens, third lens is double-convex positive lens, fourth lens is double-concave negative lens, fifth lens is double-convex positive lens, and sixth lens is meniscus concave negative lens;First, second, third, fourth lens is glass spherical lens, fifth, sixth lens is glass aspherical lens.The imaging angle of object is greater than 80 degrees, simultaneously has 3M imaging definition, F number 1.4, lower tolerance sensitivity and better high-low temperature stability and other advantages, while, can more comprehensively monitor the scene of car side rear and far place.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lenses, in particular to a large-aperture six-piece side-view camera and an imaging method thereof. BACKGROUND

[0002] In order to reduce the occurrence of traffic accidents and protect their own life and property safety, people are more willing to buy cars containing car safety technology when buying cars. Car safety technology includes lane departure warning, active collision avoidance, adaptive cruise control, traction control, etc. With the development of car safety technology, the vehicle-mounted vision system has gradually become an important part of the automotive electronic system. The side-view camera is born in this background, which is generally installed at the front fender of the vehicle. The field of view angle of the camera is generally about 90°, and the detection distance is about 80m, which is mainly used for vehicle lane changing, merging into other roads and other scene applications. The F number of the side-view camera on the market is generally between 1.6-1.8, but a larger aperture is the goal that the market is tirelessly pursuing, but this often leads to an increase in the number of lens pieces, which is not conducive to market popularization. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a large-aperture six-piece side-view camera and an imaging method thereof, which realizes 3M clear imaging while having fewer lens pieces and a larger aperture.

[0004] The present application adopts the following scheme: a large-aperture six-piece side-view camera, the optical system of the camera has lenses with optical power along the incident light path in order of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, a diaphragm is arranged between the second lens and the third lens, and the third lens and the fourth lens are tightly connected to form a cemented lens group; the first lens is a double-concave negative lens, the second lens is a double-convex positive lens, the third lens is a double-convex positive lens, the fourth lens is a double-concave negative lens, the fifth lens is a double-convex positive lens, and the sixth lens is a meniscus concave negative lens; the first, second, third, and fourth lenses are glass spherical lenses, and the fifth and sixth lenses are glass aspherical lenses.

[0005] Further, the focal length of the optical system is f, and the focal lengths of the first, second, third, fourth, fifth, and sixth lenses are f1, f2, f3, f4, f5, and f6, respectively, wherein f1, f2, f3, f4, f5, and f6 satisfy the following ratios: -2.0 < f1 / f < -1.0, 1.0 < f2 / f < 2.0, 1.0 < f3 / f < 2.0, -2.0 < f4 / f < -1.0, 1.0 < f5 / f < 2.0, and -4.0 < f6 / f < -3.0.

[0006] Further, the first lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the second lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the third lens satisfies the relationship: 1.5≤Nd≤1.8, Vd≥50.0; the fourth lens satisfies the relationship: 1.6≤Nd≤1.9, Vd≤50.0; the fifth lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≥50.0; the sixth lens satisfies the relationship: 1.8≤Nd≤2.0, Vd≤50.0, wherein Nd is the refractive index, and Vd is the Abbe number.

[0007] Further, the air gap between the first lens and the second lens is 4.5-5.0mm; the air gap between the second lens and the diaphragm is 0.1-0.5mm; the air gap between the diaphragm and the third lens is 0.5-1.0mm; the air gap between the fourth lens and the fifth lens is 0.1-0.5mm; and the air gap between the fifth lens and the sixth lens is 0.5-1.0mm.

[0008] Further, the optical total length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤5.0.

[0009] Further, the F number of the optical system is ≤1.4.

[0010] Further, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≤1.0.

[0011] Further, the rear side of the sixth lens is provided with a filter.

[0012] Another technical solution of the present application is an imaging method of the large-aperture six-lens side-view camera as described above, and the light is sequentially imaged after passing through the first lens, the second lens, the diaphragm, the third lens, the fourth lens, the fifth lens, the sixth lens and the filter.

[0013] Compared with the prior art, the present application has the following beneficial effects:

[0014] 1. The lens has an imaging angle of more than 80 degrees for an object, and has the advantages of 3M imaging clarity, F number 1.4, low tolerance sensitivity and good high-low temperature stability, etc., and can more comprehensively monitor the side and far scenes of the vehicle;

[0015] 2. By reasonably matching the optical lenses, the system structure is compact and reasonable, easy to assemble, low in tolerance sensitivity, and more suitable for large-scale high-yield production;

[0016] 3. The all-glass structure has high stability, can make good compensation for the focal plane displacement at high and low temperatures, and has complex environment adaptability;

[0017] 4. Correcting each axial chromatic aberration, sagittal chromatic aberration and high-order chromatic aberration, ensuring that the imaging system can also have high imaging quality at a large angle.

[0018] 5. Giving full play to the advantages of the aspherical lens in correcting aberration, meeting the high-definition imaging while having a smaller lens outer diameter and shorter optical total length, ensuring the miniaturization of the lens.

[0019] In order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the following will further describe the present application through specific examples and related drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 is a schematic diagram of the optical system structure of the camera of the present application;

[0021] Fig. 2 is an axial chromatic aberration diagram of the camera of the present application in the full working waveband;

[0022] Fig. 3 is a sagittal chromatic aberration diagram of the camera of the present application in the full working waveband;

[0023] Fig. 4 is a field curvature distortion diagram of the camera of the present application in the full working waveband;

[0024] Explanation of reference numerals in the drawings: STO - diaphragm; L1 - first lens; L2 - second lens; L3 - third lens; L4 - fourth lens; L5 - fifth lens; L6 - sixth lens; L7 - equivalent glass flat plate; L8 - equivalent glass flat plate; IMA - imaging surface. DETAILED DESCRIPTION

[0025] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise defined, 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 belongs.

[0026] It should be noted that the terms used herein are only for the purpose of describing the specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of the features, steps, operations, devices, components and / or combinations thereof.

[0027] As Figs. 1-4As shown, a large aperture six-piece side rear view camera, the optical system of the camera has lenses with optical power along the incident light path in order of first lens, second lens, third lens, fourth lens, fifth lens and sixth lens, a diaphragm is arranged between the second lens and the third lens, wherein the third lens and the fourth lens are tightly connected to form a cemented lens group; without considering the reverse bending caused by the aspherical coefficient, the first lens is a double-concave negative lens, the object side surface is concave, and the image side surface is concave; the second lens is a double-convex positive lens, the object side surface is convex, and the image side surface is convex; the third lens is a double-convex positive lens, the object side surface is convex, and the image side surface is convex; the fourth lens is a double-concave negative lens, the object side surface is concave, and the image side surface is convex; the fifth lens is a double-convex positive lens, the object side surface is convex, and the image side surface is convex; the sixth lens is a meniscus concave negative lens, the object side surface is convex, and the image side surface is concave; the lenses are made of glass material, the first, second, third and fourth lenses are glass spherical lenses, and the fifth and sixth lenses are glass aspherical lenses.

[0028] The third lens and the fourth lens form an achromatic double-cemented lens. Reasonable lens matching makes the optical system realize small volume, 3M, F1.4, day and night confocal, low temperature drift design, and simultaneously corrects on-axis and off-axis aberrations well, and has good imaging quality, as shown in Figs. 2-4 .

[0029] In the embodiment, the focal length of the optical system is f, and the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are f1, f2, f3, f4, f5 and f6 respectively, wherein f1, f2, f3, f4, f5 and f6 satisfy the following ratios: -2.0 < f1 / f < -1.0, 1.0 < f2 / f < 2.0, 1.0 < f3 / f < 2.0, -2.0 < f4 / f < -1.0, 1.0 < f5 / f < 2.0, and -4.0 < f6 / f < -3.0.

[0030] In the embodiment, the first lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0, Vd ≤ 50.0; the second lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0, Vd ≤ 50.0; the third lens satisfies the relationship: 1.5 ≤ Nd ≤ 1.8, Vd ≥ 50.0; the fourth lens satisfies the relationship: 1.6 ≤ Nd ≤ 1.9, Vd ≤ 50.0; the fifth lens satisfies the relationship: 1.7 ≤ Nd ≤ 2.0, Vd ≥ 50.0; and the sixth lens satisfies the relationship: 1.8 ≤ Nd ≤ 2.0, Vd ≤ 50.0, wherein Nd is the refractive index and Vd is the Abbe number.

[0031] In the embodiment, the air gap between the first lens and the second lens is 4.5-5.0 mm; the air gap between the second lens and the diaphragm is 0.1-0.5 mm; the air gap between the diaphragm and the third lens is 0.5-1.0 mm, and the diaphragm is located behind the second lens; the third lens and the fourth lens are cemented lens groups, and the air gap is 0 mm; the air gap between the fourth lens and the fifth lens is 0.1-0.5 mm; and the air gap between the fifth lens and the sixth lens is 0.5-1.0 mm.

[0032] In the embodiment, the sixth and seventh lenses are aspherical lenses, and the aspherical curve equation expression is as follows:

[0033]

[0034] wherein Z is the sagittal height of the aspherical surface at a position with 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; and A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, and W are high-order coefficients. 、 、 、 、 、 、 、

[0035] The aspherical surface coefficients of each aspherical lens are as follows:

[0036]

[0037] In the embodiment, the total optical length TTL of the optical system and the focal length f of the optical system satisfy TTL / f≤5.0.

[0038] In the embodiment, the F number of the optical system is ≤1.4.

[0039] In the embodiment, the image height H of the optical system and the focal length f of the optical system satisfy H / f≤1.0.

[0040] In the embodiment, the rear side of the sixth lens is provided with a filter.

[0041] The technical indexes achieved by the optical system in the embodiment are as follows:

[0042] (1) focal length: 5.0≤EFFL≤6.0 mm;

[0043] (2) aperture F≤1.4;

[0044] (3) field of view angle: 2w≥80°;

[0045] (4) working waveband: visible light waveband. ​

[0046] To realize the above design parameters, the specific parameter design of the optical system of the embodiment is shown in the following table:

[0047]

[0048] The optical system of the embodiment, by reasonably allocating the optical power of each lens, the surface shape, the center thickness of each lens, and the axial distance between each lens, etc., while meeting the imaging performance requirements of the lens 3M, F number 1.4, reduces the total length of the lens and the radial size of each lens, and achieves miniaturization of the lens group.

[0049] An imaging method of the large-aperture six-piece side-view camera as described above, in which light rays are sequentially imaged through the first lens, the second lens, the diaphragm, the third lens, the fourth lens, the fifth lens, the sixth lens, and the filter.

[0050] Any of the technical solutions disclosed in the above embodiments, unless otherwise stated, if a numerical range is disclosed, the disclosed numerical range is a preferred numerical range, and any person skilled in the art should understand that the preferred numerical range is only one of the many implementable numerical values with more obvious technical effects or representative values. Because there are too many values, it is impossible to enumerate them all, so the present application discloses some values to illustrate the technical solutions of the present application, and the above-mentioned enumerated values should not constitute a limitation on the protection scope of the present application.

[0051] If the present application discloses or involves mutually fixed connecting parts or structural parts, unless otherwise stated, the fixed connection can be understood as: detachable fixed connection (for example, connected by bolts or screws), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, manufactured by integral forming process) (except for obvious cases that cannot use integral forming process).

[0052] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the above embodiments, unless otherwise stated, include states or shapes that are approximate, similar or close to them.

[0053] Any of the components provided by the present application can be assembled from multiple individual components, or can be a single component manufactured by integral forming process.

[0054] The above merely describes preferred embodiments of the present application, but is not intended to limit the present application to other forms, and any person skilled in the art can make changes or modifications to the above disclosed technical contents into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments without departing from the technical solution content of the present application, and according to the technical essence of the present application, still belongs to the protection scope of the technical solution of the present application.

Claims

1. A large-aperture six-element side-rear-view camera, characterized in that: The camera's optical system comprises six lenses with optical power, arranged sequentially along the incident light path as a first lens, second lens, third lens, fourth lens, fifth lens, and sixth lens. An aperture stop is positioned between the second and third lenses. The third and fourth lenses are closely joined to form a cemented lens group. The first lens is a biconcave negative lens, the second lens is a biconvex positive lens, the third lens is a biconvex positive lens, the fourth lens is a biconcave negative lens, the fifth lens is a biconvex positive lens, and the sixth lens is a meniscus negative lens. The first, second, third, and fourth lenses are spherical glass lenses, while the fifth and sixth lenses are aspherical glass lenses. The focal length of the optical system is f, and the focal lengths of the first, second, third, fourth, fifth, and sixth lenses are f1, f2, f3, f4, f5, and f6, respectively. The ratios of f1, f2, f3, f4, f5, and f6 to f satisfy the following proportions: -2.0 < f1 / f < -1.0, 1.0 < f2 / f < 2.0, 1.0 < f6 / f ... The following parameters are given: f3 / f < 2.0, -2.0 < f4 / f < -1.0, 1.0 < f5 / f < 2.0, -4.0 < f6 / f < -3.0; the first lens satisfies the following relationship: 1.7 ≤ Nd ≤ 2.0, Vd ≤ 50.0; the second lens satisfies the following relationship: 1.7 ≤ Nd ≤ 2.0, Vd ≤ 50.0; the third lens satisfies the following relationship: 1.5 ≤ Nd ≤ 1.8, Vd ≥ 50.0; the fourth lens satisfies the following relationship: 1.6 ≤ Nd ≤ 1.9, Vd ≤ 50.0; the fifth lens satisfies the following relationship: 1.7 ≤ Nd ≤ 2.0, Vd ≥ 50.0; the sixth lens satisfies the following relationship: 1.8 ≤ Nd ≤ 2.0, Vd ≤ 50.0, where Nd is the refractive index and Vd is the Abbe constant; the total optical length (TTL) of the optical system and the focal length (f) of the optical system satisfy the following relationship: TTL / f ≤ 5.

0.

2. The large-aperture six-element side-rear view camera according to claim 1, characterized in that: The air gap between the first lens and the second lens is 4.5~5.0mm; the air gap between the second lens and the aperture is 0.1~0.5mm; the air gap between the aperture and the third lens is 0.5~1.0mm; the air gap between the fourth lens and the fifth lens is 0.1~0.5mm; and the air gap between the fifth lens and the sixth lens is 0.5~1.0mm.

3. The large-aperture six-element side-rear view camera according to claim 1, characterized in that: The F-number of the optical system is ≤1.

4.

4. The large-aperture six-element side-rear-view camera 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≤1.

0.

5. The large-aperture six-element side-rear view camera according to claim 1, characterized in that: A filter is provided on the rear side of the sixth lens.

6. An imaging method for a large-aperture six-element side-rear-view camera as described in claim 5, characterized in that: The light rays pass through the first lens, the second lens, the aperture, the third lens, the fourth lens, the fifth lens, the sixth lens, and the filter in sequence to form an image.

Images