An ultra-wide-angle camera lens suitable for a vehicle-mounted OMS system and an imaging method thereof

Abstract

The present application relates to a kind of ultra-wide-angle camera lenses suitable for vehicle-mounted OMS system, the optical system of the lens is sequentially arranged from left to right along the light path of light incidence by first lens, second lens, third lens, fourth lens, diaphragm, fifth lens, sixth lens and seventh lens is formed;Wherein without considering the inflection caused by asphericity coefficient, the first lens is a meniscus concave negative lens;Second lens is double concave negative lens;Third lens is double convex positive lens;Fourth lens is double convex positive lens;Fifth lens is double concave negative lens;Sixth lens is double convex positive lens;Seventh lens is meniscus convex positive lens;Lens is made of glass material, wherein fifth lens, sixth lens is cemented lens group, and seventh lens is glass aspheric lens.Rational lens collocation makes the optical system realize ultra-wide-angle, large aperture, day and night focus, low temperature drift design, while on-axis, off-axis aberration is well corrected, with good imaging quality.

Description

Technical Field

[0001] The present invention relates to an ultra-wide-angle camera lens suitable for a vehicle-mounted OMS system and an imaging method thereof, and relates to the technical field of lenses. Background Art

[0002] In recent years, with the continuous development of computer vision and smart cars, the smart cockpit has become another hot development trend in the automotive market, following smart driving. Also known as the intelligent vehicle occupant monitoring system (OMS), the smart cockpit not only incorporates some ADAS assisted driving technologies but also introduces several key new technologies for passengers, such as emotion recognition, forgotten object detection, posture recognition, and gesture recognition. Driving a car not only requires ensuring driver safety, but also the safety and riding experience of passengers.

[0003] As the image acquisition component of an OMS system, camera lenses require a wide field of view and high optical performance, such as high resolution. Furthermore, as a form of in-vehicle monitoring, they must operate 24 / 7, requiring high environmental stability. Currently, wide-angle lenses with a field of view of less than 120° are commonly used in OMS systems. Given the unique characteristics of OMS systems, the market demands optical lenses with a wider field of view to maximize the capture of in-vehicle image information. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide an ultra-wide-angle camera lens and an imaging method thereof suitable for an on-board OMS system.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: an ultra-wide-angle camera lens suitable for an on-board OMS system, the optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens and a seventh lens arranged in sequence from left to right along the incident light path of the light; wherein, without considering the backcurvature caused by the aspheric coefficient, the first lens is a meniscus concave negative lens, the object side surface of which is convex and the image side surface is concave; the second lens is a double concave negative lens, the object side surface of which is concave and the image side surface is concave; The side surface is concave; the third lens is a biconvex positive lens, with a convex object side and a convex image side surface; the fourth lens is a biconvex positive lens, with a convex object side and a convex image side surface; the fifth lens is a biconcave negative lens, with a concave object side and a concave image side surface; the sixth lens is a biconvex positive lens, with a convex object side and a convex image side surface; the seventh lens is a meniscus convex positive lens, with a convex object side and a concave image side surface; the lenses are made of glass, of which the fifth and sixth lenses are cemented lens groups, and the seventh lens is a glass aspherical lens. While achieving clear imaging, it has a wider field of view.

[0006] Preferably, the focal length of the optical system is set to f, and the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are f1, f2, f3, f4, f5, f6, and f7, respectively, wherein f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratio with f: -2.0 <f1 / f<-1.0,-3.0<f2 / f<-2.0,2.0<f3 / f<3.0,1.0<f4 / f<2.0,-1.0<f5 / f<0.0,1.0<f6 / f<2.0,4.0<f7 / f<5.0。

[0007] Preferably, the first lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤70.0; the third lens satisfies the relationship: 2.0≤N d ≤2.5, 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: 1.7≤N d ≤2.0, V d ≤50.0; the sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the seventh lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

[0008] Preferably, the on-axis distances between the lenses satisfy the following relationship: the air gap between the first and second lenses is 2.0-2.5 mm; the air gap between the second and third lenses is 0.0-0.5 mm; the air gap between the third and fourth lenses is 0.0-0.5 mm; the air gap between the fourth lens and the aperture is 0.0-0.5 mm; the air gap between the aperture and the fifth lens is 0.0-0.5 mm; the fifth and sixth lenses are cemented sheets with an air gap of 0 mm; and the air gap between the sixth and seventh lenses is 0.0-0.5 mm. Reducing the distances between the lenses while meeting imaging requirements is beneficial to the overall optical length of the lens.

[0009] Preferably, the aspheric curve equation of the seventh lens is expressed as:

[0010]

[0011] Among them, Z is the height of the aspheric surface from the vertex of the aspheric surface when it is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface; k is the cone constant; α1, α2, α3, α4, α5, α6, α7, and α8 are all high-order coefficients.

[0012] Preferably, the total optical length TTL of the optical system and the focal length f of the optical system satisfy the following relationship: TTL / f≤7.

[0013] Preferably, the F number of the optical system is ≤2.0.

[0014] Preferably, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≥1.0.

[0015] An imaging method for an ultra-wide-angle camera lens suitable for an on-vehicle OMS system is performed according to the following steps: the optical system of the lens is imaged after passing through a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, and a seventh lens in sequence.

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

[0017] 1. The lens has an imaging angle of more than 170 degrees and has the advantages of high imaging clarity, large aperture, low tolerance sensitivity and good high and low temperature stability. At the same time, it can monitor the scene inside the car more comprehensively.

[0018] 2. Through the reasonable matching of optical lenses, the system structure is compact and reasonable, easy to assemble, with low tolerance sensitivity, and more suitable for large-scale high-yield production;

[0019] 3. The all-glass structure, which uses a glass aspherical lens and six glass spherical lenses, has high system stability, can make good compensation for focal plane displacement at high and low temperatures, and has adaptability to complex environments;

[0020] 4. The axial chromatic aberration, vertical chromatic aberration and high-order chromatic aberration are corrected to ensure that the imaging system can have high imaging quality even at large angles.

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the optical structure of the present invention;

[0023] Figure 2 This is the full working band axial chromatic aberration diagram of the present invention;

[0024] Figure 3 This is the vertical axis chromatic aberration diagram of the full working band of the present invention;

[0025] Figure 4 This is the field curvature distortion diagram of the full working band of the present invention;

[0026] In the figure: L1-first lens; L2-second lens; L3-third lens; L4-fourth lens; STO-aperture; L5-fifth lens; L6-sixth lens; L7-seventh lens; L8-equivalent glass plate; IMA-imaging surface. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] like Figures 1 to 4 As shown, this embodiment provides an ultra-wide-angle camera lens suitable for an in-vehicle OMS system. The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, and a seventh lens, which are arranged in sequence from left to right along the incident light path of the light. Wherein, without considering the backcurvature caused by the aspheric coefficient, the first lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the second lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; 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 biconvex positive lens with a convex object-side surface and a convex image-side surface; the fifth lens is a biconcave negative lens with a concave object-side surface and a concave image-side surface; the sixth lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; the seventh lens is a meniscus convex positive lens with a convex object-side surface and a concave image-side surface; the lenses are made of glass, of which the fifth and sixth lenses are cemented lens groups, and the seventh lens is a glass aspheric lens.

[0031] The first to sixth lenses are all glass spherical lenses, and the seventh lens is a glass aspherical lens. Among them, the first lens and the second lens are both glass spherical lenses with negative optical power. While adjusting large-angle light, they also have the function of reducing the distortion of the optical system. The fifth lens and the sixth lens form an achromatic doublet lens. Reasonable lens matching enables the optical system to achieve ultra-wide angle, large aperture, day and night confocal, low-temperature drift design, and at the same time, it has a good correction for on-axis and off-axis aberrations, with good imaging quality, such as Figures 2 to 4 shown.

[0032] In an embodiment of the present invention, the focal length of the optical system is set to f, and the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are f1, f2, f3, f4, f5, f6, and f7, respectively, where f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratio with f: -2.0 <f1 / f<-1.0,-3.0<f2 / f<-2.0,2.0<f3 / f<3.0,1.0<f4 / f<2.0,-1.0<f5 / f<0.0,1.0<f6 / f<2.0,4.0<f7 / f<5.0。

[0033] In the embodiment of the present invention, the first lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤70.0; the third lens satisfies the relationship: 2.0≤N d ≤2.5, 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: 1.7≤N d ≤2.0, V d ≤50.0; the sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the seventh lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

[0034] In the embodiment of the present invention, the on-axis distances between the lenses satisfy the following relationship: the air gap between the first and second lenses is 2.0-2.5 mm; the air gap between the second and third lenses is 0.0-0.5 mm; the air gap between the third and fourth lenses is 0.0-0.5 mm; the air gap between the fourth lens and the aperture is 0.0-0.5 mm; the air gap between the aperture and the fifth lens is 0.0-0.5 mm; the fifth and sixth lenses are bonded together, and the air gap is 0 mm; and the air gap between the sixth and seventh lenses is 0.0-0.5 mm.

[0035] In this embodiment of the present invention, the aspheric curve equation of the seventh lens is expressed as:

[0036]

[0037] Among them, Z is the height of the aspheric surface from the vertex of the aspheric surface when it is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface; k is the cone constant; α1, α2, α3, α4, α5, α6, α7, and α8 are all high-order coefficients.

[0038] In the embodiment of the present invention, the total optical length TTL of the optical system and the focal length f of the optical system satisfy the following relationship: TTL / f≤7.

[0039] In an embodiment of the present invention, the F number of the optical system is ≤2.0.

[0040] In the embodiment of the present invention, the image height H of the optical system and the focal length f of the optical system satisfy the following relationship: H / f≥1.0.

[0041] In the embodiment of the present invention, the technical indicators achieved by the optical system of this embodiment are as follows:

[0042] (1) Focal length: 2.0 ≤ EFFL ≤ 3.0 mm;

[0043] (2) Aperture F≤1.9;

[0044] (3) Field of view: 2w ≥ 170°;

[0045] (4) Working band: visible light band and 940nm short infrared band.

[0046] To achieve the above design parameters, the specific design adopted by the optical system of this embodiment is shown in the following table:

[0047]

[0048]

[0049] The aspheric coefficients of the aspheric lenses of the optical system of this embodiment are as follows:

[0050]

[0051] The optical system of this embodiment satisfies the requirements of ultra-wide angle while meeting the requirements of lens imaging performance by reasonably allocating the optical power, surface shape, center thickness of each lens, and on-axis distance between lenses.

[0052] An imaging method for an ultra-wide-angle camera lens suitable for an on-vehicle OMS system is performed according to the following steps: the optical system of the lens is imaged after passing through a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, and a seventh lens in sequence.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. An ultra-wide-angle camera lens suitable for an in-vehicle OMS system, characterized by: The optical system of the lens consists of a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, and a seventh lens arranged in sequence from left to right along the light incident optical path; among them, without considering the inflection caused by the aspherical coefficient, the first lens is a meniscus concave negative lens, with its object side being convex and its image side being concave; the second lens is a double concave negative lens, with its object side being concave and its image side being concave; the third lens is a double convex positive lens, with its object side being convex and its image side being convex; the fourth lens is a double convex positive lens, with its object side being convex and its image side being convex; the fifth lens is a double concave negative lens, with its object side being concave and its image side being concave; the sixth lens is a double convex positive lens, with its object side being convex and its image side being convex; the seventh lens is a meniscus convex positive lens, with its object side being convex and its image side being concave; all lenses are made of glass materials, among which the fifth lens and the sixth lens form a cemented lens group, and the seventh lens is a glass aspherical lens; 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, the sixth lens, and the seventh lens are f1, f2, f3, f4, f5, f6, and f7 respectively, where f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratios with f: -2.0 < f1 / f < -1.0, -3.0 < f2 / f < -2.0, 2.0 < f3 / f < 3.0, 1.0 < f4 / f < 2.0, -1.0 < f5 / f < 0.0, 1.0 < f6 / f < 2.0, 4.0 < f7 / f < 5.0; the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 7.

2. The ultra-wide-angle camera lens suitable for an in-vehicle OMS system according to claim 1, characterized in that: The first lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤70.0; the third lens satisfies the relationship: 2.0≤N d ≤2.5, 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: 1.7≤N d ≤2.0, V d ≤50.0; the sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the seventh lens satisfies the relationship: 1.7≤N d ≤2.0, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

3. The ultra-wide-angle camera lens suitable for an in-vehicle OMS system according to claim 1, characterized in that: The on-axis distances between the lenses satisfy the following relationships: The air gap between the first lens and the second lens is: 2.0 - 2.5 mm; The air gap between the second lens and the third lens is: 0.0 - 0.5 mm; The air gap between the third lens and the fourth lens is: 0.0 - 0.5 mm; The air gap between the fourth lens and the aperture is: 0.0 - 0.5 mm; The air gap between the aperture and the fifth lens is: 0.0 - 0.5 mm; The fifth lens and the sixth lens form a cemented lens group, and the air gap is 0 mm; The air gap between the sixth lens and the seventh lens is: 0.0 - 0.5 mm.

4. The ultra-wide-angle camera lens suitable for an in-vehicle OMS system according to claim 1, characterized in that: The expression of the aspherical curve equation of the seventh lens is: where, z is the sagitta height from the vertex of the aspherical surface when the aspherical surface is at a position with a height of h along the optical axis direction; c is the paraxial curvature of the aspherical surface, and r is equal to 1 / c; k is the conic constant; α1, α2, α3, α4, α5, α6, α7, and α8 are all high-order term coefficients.

5. The ultra-wide-angle camera lens suitable for an in-vehicle OMS system according to claim 1, characterized in that: The F-number of the optical system ≤ 2.

0.

6. The ultra-wide-angle camera lens suitable for an in-vehicle OMS system according to claim 1, characterized in that:

7. An imaging method for an ultra-wide-angle camera lens suitable for an in-vehicle OMS system according to any one of claims 1 to 6, characterized in that: The image height H of the optical system and the focal length f of the optical system satisfy: H / f ≥ 1.

0. It is carried out according to the following steps: The light forms an image after passing through the first lens, the second lens, the third lens, the fourth lens, the aperture, the fifth lens, the sixth lens, and the seventh lens in sequence.

Images