A front-view ultra-wide-angle binocular camera and an imaging method thereof

Abstract

The present application relates to a kind of front view ultra-wide-angle binocular camera, the optical system of camera is by first lens, second lens, third lens, diaphragm, 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 a meniscus concave negative lens, second lens is a meniscus concave positive lens, third lens is a meniscus convex positive lens, fourth lens is a double convex positive lens, fifth lens is a meniscus concave negative lens, sixth lens is a meniscus convex positive lens, all lenses are made of glass material, wherein first, sixth lens is glass aspherical lens, fourth, fifth lens is made into cemented lens group.In the realization of wide-angle 120 ° clear imaging, it has smaller size, higher environmental stability.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of front view ultra-wide-angle binocular camera and its imaging method, it is related to lens technical field. BACKGROUND

[0002] Automobile safety technology has: lane departure warning, active collision avoidance, adaptive cruise control, traction control etc.. Vehicle front view camera system is a kind of automobile safety technology with lane departure warning function, vehicle front view camera module plays an important role as the hardware terminal of the system.Vehicle front view camera module is generally divided into two kinds, one is vehicle monocular camera module, another is vehicle binocular camera module.Vehicle monocular camera module scheme is lower in cost, when cooperating with radar system, it has good use effect.But binocular camera can complete 3D stereoscopic recognition function, has significant advantage in completing target tracking, position prediction, and can also realize target speed detection if cooperating with millimeter wave radar.At present, the main problems of vehicle binocular camera module are that field angle is small, cost is high, system is complex, product miniaturization is difficult etc.. 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 kind of front view ultra-wide-angle binocular camera and its imaging method.

[0004] In order to solve the above technical problems, the technical scheme of the present application is: a kind of front view ultra-wide-angle binocular camera, the optical system of camera is by first lens, second lens, third lens, diaphragm, fourth lens, fifth lens and sixth lens are sequentially arranged from left to right along the light incident path of light;In the case where the reverse bending caused by asphericity coefficient is not considered, the first lens is a concave negative lens, the object side is convex, and the image side is concave;Second lens is a concave positive lens, the object side is concave, and the image side is convex;Third lens is a convex positive lens, the object side is convex, and the image side is concave;Fourth lens is a double convex positive lens, the object side is convex, and the image side is convex;Fifth lens is a concave negative lens, the object side is concave, and the image side is convex;Sixth lens is a convex positive lens, the object side is convex, and the image side is concave;All lenses are made of glass material, wherein the first and sixth lenses are glass aspheric lenses, and the fourth and fifth 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, 51.0 < f2 / f < 52.0, 1.0 < f3 / f < 2.0, 0.0 < f4 / f < 1.0, -2.0 < f5 / f < -1.0, and 13.0 < f6 / f < 14.0.

[0006] Preferably, the first lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≥ 50.0; the second lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, 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: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the fifth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≤ 50.0; and the sixth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, 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 2.5-3.0 mm; the air gap between the second lens and the third lens is 0.1-0.5 mm; the air gap between the third lens and the diaphragm is 1.5-2.0 mm; the air gap between the diaphragm and the fourth lens is 0.5-1.0 mm; the fourth lens and the fifth lens are a cemented lens group, and the air gap is 0 mm; and the air gap between the fifth lens and the sixth lens is 1.5-2.0 mm.

[0008] Preferably, the aspherical surface curve equation of the first lens and the sixth lens is as follows:

[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 ≤1.5.

[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 rear side of the sixth lens is provided with a filter.

[0015] An imaging method of a front-view super-wide-angle binocular camera is performed in the following steps: an optical system is sequentially imaged after a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a 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 120 degrees for an object, and has the advantages of high imaging definition, large light aperture, low tolerance sensitivity and good high-low temperature stability, etc., and can monitor the scene in front of a vehicle more comprehensively;

[0018] 2. By reasonably matching the optical lenses, the system structure is compact and reasonable, the overall volume is reduced, assembly is easy, tolerance sensitivity is low, and it is more suitable for large-scale high-yield production;

[0019] 3. The all-glass lens structure can compensate for the displacement of the focal plane at high and low temperatures, and has high adaptability to complex environments;

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

[0021] The present application will be further described in detail below in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is a schematic diagram of the optical structure of the present application;

[0023] Fig. 2 is an axial color difference graph of the full working waveband of the present application;

[0024] Fig. 3 is a sagittal color difference graph of the full working waveband of the present application;

[0025] Fig. 4 is a field curvature distortion graph of the full working waveband of the present application;

[0026] 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

[0027] The application will be further described below in conjunction with the accompanying drawings and examples.

[0028] 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.

[0029] It should be noted that the terms used herein are only for the purpose of describing 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.

[0030] As shown in Figs. 1-4 The present embodiment provides a front-view ultra-wide-angle binocular camera, the optical system of the camera is composed of a first lens, a second lens, a third lens, a diaphragm, 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 meniscus concave positive lens, the object side is concave, and the image side is convex; the third lens is a meniscus convex positive lens, the object side is convex, and the image side is concave; the fourth lens is a double-convex positive lens, the object side is convex, and the image side is convex; the fifth lens is a meniscus concave negative lens, the object side is concave, and the image side is convex; the sixth lens is a meniscus convex positive lens, the object side is convex, and the image side is concave; all lenses are made of glass material, wherein the first and sixth lenses are glass aspherical lenses, and the fourth and fifth lenses form a cemented lens group.

[0031] Among them, the first lens is a glass aspherical lens with negative focal power, which adjusts the large-angle light and has the effect of reducing head distortion. The fourth lens and the fifth lens form an achromatic double-cemented lens. Reasonable lens matching makes the head achieve small volume, ultra-wide angle, large aperture, day and night confocal, low temperature drift design, and at the same time, on-axis and off-axis aberrations are well corrected, with good imaging quality, as shown in Figs. 2 to 4 .

[0032] In the embodiment of the present application, 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, 51.0 < f2 / f < 52.0, 1.0 < f3 / f < 2.0, 0.0 < f4 / f < 1.0, -2.0 < f5 / f < -1.0, and 13.0 < f6 / f < 14.0.

[0033] In the embodiment of the present application, the first lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≥ 50.0; the second lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, 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: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the fifth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≤ 50.0; and the sixth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, 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 on-axis distance between each lens satisfies the following relationships: the air gap between the first lens and the second lens is 2.5-3.0 mm; the air gap between the second lens and the third lens is 0.1-0.5 mm; the air gap between the third lens and the diaphragm is 1.5-2.0 mm; the air gap between the diaphragm and the fourth lens is 0.5-1.0 mm; the fourth lens and the fifth lens are cemented lens groups, and the air gap is 0 mm; and the air gap between the fifth lens and the sixth lens is 1.5-2.0 mm.

[0035] In the embodiment of the present application, the aspherical surface curve equation expression of the first lens and the sixth 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 ≤1.5.

[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 rear side of the sixth lens is provided with a filter.

[0042] An imaging method of a front-view super wide-angle binocular camera is performed in the following steps: an optical system is sequentially imaged after a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens and a sixth lens.

[0043] In the embodiment of the present application, the technical indicators realized by the embodiment are as follows:

[0044] (1) focal length: 5.0≤EFFL≤6.0mm;

[0045] (2) aperture F≤1.5;

[0046] (3) field of view angle: 2w≥120°;

[0047] (4) working waveband: visible light waveband.

[0048] To realize the above design parameters, the specific design adopted by the embodiment is shown in the following table:

[0049]

[0050]

[0051] The aspheric coefficients of each aspheric lens of the head of the embodiment are as follows:

[0052]

[0053] The head of the embodiment reasonably allocates the optical power of each lens, the surface shape, the center thickness of each lens and the axial distance between each lens, etc., so as to meet the requirements of the super wide-angle imaging performance of the lens, reduce the total length of the lens and the radial size of each lens, and realize the miniaturization of the lens group.

[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 front-facing ultra-wide-angle dual-lens camera, characterized in that: The optical system of the camera is composed of a first lens, a second lens, a third lens, a diaphragm, 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 convex, and the image side surface of which is concave; the second lens is a meniscus concave positive lens, the object side surface of which is concave, and the image side surface of which is convex; the third lens is a meniscus convex positive lens, the object side surface of which is convex, and the image side surface of which is concave; the fourth 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 fifth 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 sixth lens is a meniscus convex positive lens, the object side surface of which is convex, and the image side surface of which is concave; all the lenses are made of glass material, wherein the first lens and the sixth lens are glass aspherical lenses, and the fourth lens and the fifth lens 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, 51.0 < f2 / f < 52.0, 1.0 < f3 / f < 2.0, 0.0 < f4 / f < 1.0, -2.0 < f5 / f < -1.0, 13.0 < f6 / f < 14.0; the first lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≤ 50.0; the second lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, 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: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the fifth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≤ 50.0; the sixth lens satisfies the relationship: 1.6 ≤ N d ≤ 1.9, V d ≤ 50.0; wherein N d is the refractive index, V d is the Abbe number; the optical total length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 5.

0.

2. The front-facing ultra-wide dual-lens camera of claim 1, wherein: The on-axis distance between each lens satisfies the following relationship: the air gap between the first lens and the second lens is 2.5-3.0 mm; the air gap between the second lens and the third lens is 0.1-0.5 mm; the air gap between the third lens and the diaphragm is 1.5-2.0 mm; the air gap between the diaphragm and the fourth lens is 0.5-1.0 mm; the fourth lens and the fifth lens form a cemented lens group, and the air gap is 0 mm; the air gap between the fifth lens and the sixth lens is 1.5-2.0 mm.

3. The front-facing ultra-wide dual-lens camera of claim 1, wherein: The aspherical curve equation expression of the first lens and the sixth lens is as follows: 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; α1, α2, α3, α4, α5, α6, α7 and α8 are high-order coefficients.

4. The front-facing ultra-wide dual-lens camera of claim 1, wherein: The F number of the optical system is ≤1.

5.

5. The front-facing ultra-wide dual-lens camera of 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. The front-facing ultra-wide dual-lens camera of claim 1, wherein: The rear side of the sixth lens is provided with a filter.

7. An imaging method of the front-view ultra-wide-angle dual-camera according to any one of claims 1-6, characterized in that, The following steps are performed: incident light passes through the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens and the sixth lens in sequence to form an image.

Images