A six-piece side-view camera and imaging method thereof

Abstract

The present application relates to a kind of six-piece side rear view camera, the optical system of camera is by first lens, second lens, diaphragm, third lens, fourth lens, fifth lens and sixth lens are sequentially arranged from left to right along the light path of light incidence composition;In the case where not considering the inflection caused by aspherical coefficient, first lens is meniscus concave negative lens, second lens is double convex positive lens, third lens is double convex positive lens, fourth lens is meniscus concave negative lens, fifth lens is double convex positive lens, sixth lens is flat concave negative lens, all lenses are made of glass material, wherein first lens is glass aspherical lens, third, fourth lens constitutes cemented lens group.3M clear imaging is realized while having less piece number and smaller size.

Description

TECHNICAL FIELD

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

[0002] With the development of automobile safety technology, the vehicle-mounted vision system gradually becomes an important part of the automobile electronic system. In order to achieve the goal of safe driving, different parts of the automobile begin to install the vehicle-mounted vision system with the vehicle-mounted camera module as the core. For example, the installation at the side front of the A-pillar can effectively reduce the visual blind area on both sides of the front of the vehicle, the installation at the lower side of the vehicle trunk can effectively reduce the visual blind area on the rear side when reversing, etc. The side rear 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. It is mainly used in vehicle lane changing, merging into other roads and other scene applications. The market is constantly pursuing higher pixel density and longer detection distance, because this means higher accuracy and practicality, but this often leads to an increase in the number of lens pieces, which is not conducive to the popularization of the market. SUMMARY

[0003] In view of the deficiencies of the prior art, the technical problem to be solved by the present application is to provide a six-piece side rear view camera and an imaging method thereof.

[0004] In order to solve the above technical problems, the technical scheme of the present application is as follows: a six-piece side rear view camera, the optical system of the camera is composed of a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in order from left to right along the light incident path; without considering the reverse curvature caused by the aspherical coefficient, the first lens is a meniscus concave negative lens, the object side surface of which is convex, and the image side surface of which is concave; the second lens is a double-convex positive lens, the object side surface of which is convex, and the image side surface of which is convex; the third lens is a double-convex positive lens, the object side surface of which is convex, and the image side surface of which is convex; the fourth lens is a meniscus concave negative lens, the object side surface of which is concave, and the image side surface of which is convex; the fifth lens is a double-convex positive lens, the object side surface of which is convex, and the image side surface of which is convex; the sixth lens is a flat concave negative lens, the object side surface of which is concave, and the image side surface of which is flat; all the lenses are made of glass material, wherein the first lens is a glass aspherical lens, and the third and fourth lenses form a cemented lens group.

[0005] Preferably, the focal length of the optical system is set as 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 -2.0 < f6 / f < -1.0.

[0006] Preferably, the first lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, 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: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the fourth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≤ 50.0; the fifth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; and the sixth lens satisfies the relationship: 1.8 ≤ N d ≤ 2.0, V d ≤ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0007] Preferably, the axial distance between the lenses satisfies the following relationships: the air gap between the first lens and the second lens is 6.5-7.0 mm; the air gap between the second lens and the diaphragm is 0.1-0.5 mm; the diaphragm is on the third lens; the third lens and the fourth lens are a cemented lens group, and the air gap is 0 mm; the air gap between the fourth lens and the fifth lens is 1.0-1.5 mm; and the air gap between the fifth lens and the sixth lens is 0.1-0.5 mm.

[0008] Preferably, the aspherical surface curve equation of the first lens is:

[0009]

[0010] wherein Z is the sagittal height of the aspherical surface at a height of r along the optical axis; c is the paraxial curvature of the aspherical surface; k is the conic constant; and α1, α2, α3, α4, α5, α6, α7 and α8 are high-order coefficients.

[0011] Preferably, the total track length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤5.0.

[0012] Preferably, the F number of the optical system is ≤1.8.

[0013] Preferably, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≤1.0.

[0014] Preferably, the stop of the optical system is located on the object side of the third lens.

[0015] An imaging method of a six-piece side rear view camera, which is performed according to the following steps: the optical system of the camera is sequentially imaged after the first lens, the second lens, the stop, the third lens, the fourth lens, the fifth lens and the sixth lens.

[0016] Compared with the prior art, the present application has the following beneficial effects:

[0017] 1. The lens has an imaging angle of more than 80 degrees for an object, and has the advantages of 3M imaging clarity, large light aperture, low tolerance sensitivity and good high and low temperature stability, etc., and can more comprehensively monitor the side rear and distant scene of a vehicle;

[0018] 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;

[0019] 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;

[0020] 4. The axial color difference, the sagittal color difference and the high-order color difference are corrected, so that the imaging system can also have high imaging quality at a large angle.

[0021] 5. The advantages of aspheric lens in correcting aberration are fully exerted, so that the lens has smaller lens outer diameter and shorter total optical length, and ensures the miniaturization of the lens.

[0022] The present application will be further described in detail below in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 is a schematic diagram of the optical structure of the present application;

[0024] Fig. 2 is an axial color difference diagram of the full working waveband of the present application;

[0025] Fig. 3 is a sagittal color difference diagram of the full working waveband of the present application;

[0026] Fig. 4 is the full working waveband field curvature distortion map of the present application;

[0027] In the figure: 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 one; L8 - equivalent glass flat plate two; IMA - imaging plane. DETAILED DESCRIPTION

[0028] The present application is further described below in conjunction with the accompanying drawings and examples.

[0029] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the 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.

[0030] It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It is further understood that the terms "comprising," "including," and / or "containing" when used herein, do not exclude other components or steps. It is also understood that the terms "including" and / or "comprising," when used herein, mean "including, but not limited to," and / or "comprising, but not limited to."

[0031] As shown in Figs. 1-4 The present embodiment provides a six-piece side-view camera, the optical system of the camera is composed of a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in order from left to right along the light incident path; without considering the reverse bending caused by the aspherical coefficient, the first lens is a meniscus concave negative lens, the object side is convex, and the image side is concave; the second lens is a biconvex positive lens, the object side is convex, and the image side is convex; the third lens is a biconvex positive lens, the object side is convex, and the image side is convex; the fourth lens is a meniscus concave negative lens, the object side is concave, and the image side is convex; the fifth lens is a biconvex positive lens, the object side is convex, and the image side is convex; the sixth lens is a flat concave negative lens, the object side is concave, and the image side is flat; all lenses are made of glass material, wherein the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are glass spherical lenses, the first lens is a glass aspherical lens, and the third lens and the fourth lens form an achromatic double cemented lens group. Reasonable lens matching makes the optical system realize small volume, 3M, large aperture, day and night confocal, low temperature drift design, and at the same time, on-axis and off-axis aberrations are well corrected, and the imaging quality is good, as shown in Figs. 2 to 4 .

[0032] In the embodiment of the present application, 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 -2.0 < f6 / f < -1.0.

[0033] In the embodiment of the present application, the first lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, 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: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the fourth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≤ 50.0; the fifth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; the sixth lens satisfies the relationship: 1.8 ≤ N d ≤ 2.0, V d ≤ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0034] In the embodiment of the present application, the axial distance between each lens satisfies the following relationship, the air gap between the first lens and the second lens is 6.5-7.0 mm; the air gap between the second lens and the diaphragm is 0.1-0.5 mm; the diaphragm is on the third 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 1.0-1.5 mm; and the air gap between the fifth lens and the sixth lens is 0.1-0.5 mm.

[0035] In the embodiment of the present application, the aspherical surface curve equation expression of the first lens is:

[0036]

[0037] 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 α1, α2, α3, α4, α5, α6, α7 and α8 are high-order coefficients.

[0038] In the embodiment of the present application, the total track length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤5.0.

[0039] In the embodiment of the present application, the F number of the optical system is ≤1.8.

[0040] In the embodiment of the present application, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≤1.0.

[0041] In the embodiment of the present application, the stop of the optical system is located on the object side of the third lens.

[0042] In the embodiment of the present application, the rear side of the sixth lens is provided with a filter.

[0043] An imaging method of a six-piece side-view camera, which is performed according to the following steps: the optical system of the camera sequentially passes through the first lens, the second lens, the stop, the third lens, the fourth lens, the fifth lens and the sixth lens to form an image.

[0044] In the embodiment of the present application, the technical indexes realized by the optical system of the embodiment are as follows:

[0045] (1) focal length: 6.0≤EFFL≤7.0mm;

[0046] (2) aperture F≤1.8;

[0047] (3) field of view angle: 2w≥80°;

[0048] (4) working waveband: visible light waveband.

[0049] In order to realize the above design parameters, the specific design of the optical system of the embodiment is shown in the following table:

[0050]

[0051]

[0052] The aspheric coefficients of the aspheric lenses of the optical system of the embodiment are as follows:

[0053]

[0054] The optical system of the embodiment realizes the miniaturization of the lens group by reasonably distributing the optical power of each lens, the surface shape, the central thickness of each lens and the axial distance between each lens, etc., while meeting the 3M imaging performance requirements of the lens.

[0055] 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 six-piece side view camera, characterized by: The optical system of the camera is composed of a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence along the light path of the incident light from left to right; without considering the reverse bending caused by the aspherical coefficient, the first lens is a meniscus concave negative lens, the object side surface of which is a convex surface and the image side surface of which is a concave surface; the second lens is a double-convex positive lens, the object side surface of which is a convex surface and the image side surface of which is a convex surface; the third lens is a double-convex positive lens, the object side surface of which is a convex surface and the image side surface of which is a convex surface; the fourth lens is a meniscus concave negative lens, the object side surface of which is a concave surface and the image side surface of which is a convex surface; the fifth lens is a double-convex positive lens, the object side surface of which is a convex surface and the image side surface of which is a convex surface; the sixth lens is a flat concave negative lens, the object side surface of which is a concave surface and the image side surface of which is a plane; all the lenses are made of glass material, wherein the first lens is a glass aspherical lens, and the third and fourth lenses form a cemented lens group; the focal length of the optical system is set as 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, -2.0 < f6 / f < -1.0; the first lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, 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: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the fourth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≥ 50.0; the fifth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; the sixth lens satisfies the relationship: 1.8 ≤ N d ≤ 2.0, V d ≤ 50.0; wherein N d is the refractive index, V d is the Abbe number; the optical total track length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 5.

0.

2. The six-piece side view camera according to claim 1, characterized in that: The on-axis distance between each lens satisfies the following relationship: the air gap between the first lens and the second lens is 6.5-7.0 mm; the air gap between the second lens and the diaphragm is 0.1-0.5 mm; the diaphragm is on the object side surface of the third lens; the third lens and the fourth lens are a cemented lens group with an air gap of 0 mm; the air gap between the fourth lens and the fifth lens is 1.0-1.5 mm; and the air gap between the fifth lens and the sixth lens is 0.1-0.5 mm.

3. The six-piece side view camera according to claim 1, wherein: The aspherical curve equation expression of the first lens is: wherein z is the sagittal height of the aspherical surface at a height of r along the optical axis; c is the paraxial curvature of the aspherical surface, r = 1 / c; k is the conic constant; and α1, α2, α3, α4, α5, α6, α7 and α8 are high-order coefficients.

4. The six-piece side view camera according to claim 1, wherein: The F number of the optical system is ≤1.

8.

5. The six-piece side view camera according to claim 1, wherein: The image height H of the optical system and the focal length f of the optical system satisfy: H / f ≤1.

0.

6. A method of imaging a six-piece side-view camera as claimed in any one of claims 1-5, characterized in that, The following steps are performed: the optical system of the camera sequentially passes through the first lens, the second lens, the diaphragm, the third lens, the fourth lens, the fifth lens and the sixth lens to form an image.

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