3m five-piece front-facing primary camera and imaging method thereof

Abstract

The application relates to a 3M five-piece front-view main camera and an imaging method thereof, which is composed of a first lens, a second lens, a diaphragm, a third lens, a fourth lens and a fifth lens arranged in sequence from left to right along the light incident path; the first lens is a meniscus negative lens, the object side surface of which is a convex surface, and the image side surface is a concave surface; the second lens is a biconvex positive lens, the object side surface of which is a convex surface, and the image side surface is a convex surface; the third lens is a biconvex positive lens, the object side surface of which is a convex surface, and the image side surface is a convex surface; the fourth lens is a biconcave negative lens, the object side surface of which is a concave surface, and the image side surface is a concave surface; and the fifth lens is a biconvex positive lens, the object side surface of which is a convex surface, and the image side surface is a convex surface. The application has the advantages of reasonable design and simple structure, and through reasonable distribution of the optical power, surface type, central thickness of each lens and the axial distance between the lenses, the total length of the lens and the radial size of each lens are reduced while the 3M imaging performance requirement of the five-piece lens is met, and the lens group is miniaturized.

Description

Technical Field

[0001] The present invention relates to a 3M five-piece front-view main camera and an imaging method thereof. Background Art

[0002] Currently, in-vehicle cameras are categorized by their installation location into five main categories: front-view cameras, surround-view cameras, rear-view cameras, side-view cameras, and built-in cameras. Front-view cameras are primarily installed on the windshield and provide visual perception and recognition for the vehicle. Based on their functionality, they can be further categorized as front-view main cameras, front-view narrow-angle cameras, and front-view wide-angle cameras. Front-view main cameras serve as the main camera in Level 2 ADAS systems. Their fields of view typically range from 30°, 50°, 60°, 100°, and 120°, with a detection range of 150-170 meters. They provide Level 2 functions such as road condition monitoring and lane departure warning. Under these circumstances, higher pixel density and longer detection ranges translate to greater accuracy and practicality, which often requires an increase in the number of lenses. The market generally adopts designs with seven or more lenses, which hinders cost reduction and lens adoption. Summary of the Invention

[0003] The present invention improves the above-mentioned problem. That is, the technical problem to be solved by the present invention is to provide a 3M five-piece front-view main camera and an imaging method thereof, which has a smaller external size while achieving clear imaging of the five-piece 3M.

[0004] The present invention is constructed as follows: it consists of a first lens, a second lens, an aperture, a third lens, a fourth lens and a fifth lens, which are arranged in sequence from left to right along the incident optical path of the light; the first lens is a meniscus negative lens, whose object side surface is convex and whose image side surface is concave; the second lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the third lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the fourth lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; and the fifth lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex.

[0005] Furthermore, 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, and the fifth lens are f1, f2, f3, f4, f5, respectively. 5， Among them, f1, f2, f3, f4, f5 and f satisfy the following ratio: -2.0 <f1 / f<-1.0,1.0<f2 / f<2.0,1.0<f3 / f<2.0,-1.0<f4 / f<0.0,1.0<f5 / f<2.0。

[0006] Furthermore, the first lens satisfies the relationship: 1.5≤N d ≤1.8, Vd ≤50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, 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: 1.8≤N d ≤2.0, V d ≤50.0; the fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

[0007] Furthermore, the air gap between the first lens and the second lens is 6.0~6.5mm; the aperture is located on the second lens, and the air gap between the aperture and the third lens is 0.5~1.0mm; 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 0.1~0.5mm.

[0008] Furthermore, the first lens and the fifth lens are aspherical lenses, and the aspherical curve equation is expressed as:

[0009] ;

[0010] Among them, Z is the height of the aspheric surface from the vertex of the aspheric surface when it is at a height of r 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.

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

[0012] Furthermore, a first equivalent glass plate, a second equivalent glass plate and an imaging surface are sequentially provided on the rear side of the fifth lens.

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

[0014] Furthermore, the F number of the optical system is ≤1.6.

[0015] Furthermore, in the imaging method of the 3M five-lens front-view main camera, when light is incident, the light path enters the first lens, second lens, aperture, third lens, fourth lens and fifth lens in sequence to form an image.

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

[0017] 1. The lens has an imaging angle greater than 80 degrees, and features 3M imaging clarity, a large aperture, low tolerance sensitivity, and excellent high and low temperature stability. This allows for more comprehensive monitoring of the scene in front of the vehicle and in the distance. 2. By rationally matching the various optical lenses, the system consists of five elements, ensuring a compact and reasonable structure, easy assembly, and low tolerance sensitivity, making it more suitable for large-scale, high-yield production. 3. The all-glass structure offers high stability, can effectively compensate for focal plane displacement at high and low temperatures, and is adaptable to complex environments. 4. Axial chromatic aberration, vertical chromatic aberration, and high-order chromatic aberration are corrected to ensure the imaging system has high image quality even at large angles. 5. Leveraging the advantages of aspheric surfaces, the lens reduces aberrations while further reducing the number of elements and shortening the lens length. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a schematic diagram of the optical structure of an embodiment of the present invention;

[0019] Figure 2 This is a diagram of axial chromatic aberration in the full working band of an embodiment of the present invention;

[0020] Figure 3 This is a vertical axis chromatic aberration diagram for the entire working band of an embodiment of the present invention;

[0021] Figure 4 This is a field curvature distortion diagram for all working bands according to an embodiment of the present invention;

[0022] In the figure: L1-first lens; L2-second lens; L3-third lens; STO-aperture; L4-fourth lens; L5-fifth lens; L6-first equivalent glass plate; L7-second equivalent glass plate; IMA-imaging surface. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example: Figures 1 to 4As shown, the present invention provides a 3M five-lens front-view main camera, including a first lens L1, a second lens L2, an aperture STO, a third lens L3, a fourth lens L4 and a fifth lens L5, which are arranged in sequence from left to right along the incident light path of the light; the above-mentioned first lens and fifth lens are aspherical lenses, and the second lens, third lens and fourth lens are all glass spherical lenses; the lenses are made of glass material, wherein the first lens has a negative optical focal length. While adjusting large-angle light, it has the function of reducing aberrations such as distortion of the optical system as an aspherical lens. The third lens and the fourth lens form an achromatic doublet lens. Through reasonable lens matching, the optical system can achieve a small size, 3M, large aperture, day and night confocal, and low-temperature drift design through a five-lens structure, while well correcting on-axis and off-axis aberrations, and having good imaging quality.

[0025] Without considering the backcurvature caused by the aspheric coefficient, the first lens is a meniscus negative lens, whose object side surface is convex and whose image side surface is concave; the second lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the third lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the fourth lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; the fifth lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex.

[0026] In the embodiment of the present invention, 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, and the fifth lens are f1, f2, f3, f4, and f5 respectively. 5， Among them, f1, f2, f3, f4, f5 and f satisfy the following ratio: -2.0 <f1 / f<-1.0,1.0<f2 / f<2.0,1.0<f3 / f<2.0,-1.0<f4 / f<0.0,1.0<f5 / f<2.0。

[0027] 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 ≥50.0; the third lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the fourth lens satisfies the relationship: 1.8≤N d ≤2.0, V d ≤50.0; the fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

[0028] In an embodiment of the present invention, the air gap between the first lens and the second lens is 6.0-6.5 mm; the aperture is located on the second lens, and the air gap between the aperture and the third lens is 0.5-1.0 mm; 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 0.1-0.5 mm.

[0029] In an embodiment of the present invention, the first lens and the fifth lens are aspherical lenses, and the aspherical curve equation is expressed as:

[0030] ;

[0031] Among them, Z is the height of the aspheric surface from the vertex of the aspheric surface when it is at a height of r 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.

[0032] 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≤5.0.

[0033] In the embodiment of the present invention, a first equivalent glass plate L6, a second equivalent glass plate L7 and an imaging surface IMA are sequentially provided on the rear side of the fifth lens.

[0034] 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.

[0035] In an embodiment of the present invention, the F number of the optical system is ≤1.6.

[0036] In the embodiment of the present invention, during imaging: when light is incident, the light path enters the first lens, the second lens, the aperture, the third lens, the fourth lens and the fifth lens in sequence to form an image.

[0037] The technical indicators achieved by the optical system of the embodiment of the present invention are as follows: (1) focal length: 6.0≤EFFL≤7.0mm; (2) aperture F≤1.6; (3) field of view angle: 2w≥80°; (4) operating band: visible light band.

[0038] To achieve the above design parameters, the specific design parameters of the optical system of the embodiment of the present invention are shown in Table 1 below:

[0039]

[0040] Table 1

[0041] The aspheric coefficients of the aspheric lenses of the optical system according to the embodiment of the present invention are shown in Table 2 below:

[0042]

[0043] Table 2

[0044] In an embodiment of the present invention, the optical system reduces the total length of the lens and the radial dimensions of each lens while meeting the 3M imaging performance requirements of the five-piece lens by reasonably allocating the optical focal length, surface shape, center thickness of each lens, and axial distance between each lens, thereby miniaturizing the lens group.

[0045] Unless otherwise stated, for any of the technical solutions disclosed in the present invention, if a numerical range is disclosed, the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is merely a numerical range that is representative or has a more obvious technical effect among many feasible numerical values. Due to the large number of numerical values, it is impossible to enumerate them exhaustively. Therefore, the present invention discloses some numerical values ​​to illustrate the technical solutions of the present invention. Moreover, the numerical values ​​listed above should not be construed as limiting the scope of protection of the present invention.

[0046] At the same time, if the above-mentioned invention discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, using bolts or screws to connect), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by integral molding using a casting process) (except where it is obviously impossible to use an integrated molding process).

[0047] If words such as "first" and "second" are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of description to distinguish between components. Unless otherwise stated, the above words have no special meaning.

[0048] In addition, unless otherwise stated, the terms used in any technical solution disclosed in the present invention to express positional relationships or shapes include states or shapes that are approximate, similar, or close thereto.

[0049] Any component provided by the present invention may be assembled from multiple separate components, or may be a separate component manufactured by an integral molding process.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention. They should all be included in the scope of the technical solution for protection of the present invention.

Claims

1. A 3M five-element front-facing main camera, characterized in that: The lens system is composed of a first lens, a second lens, an aperture, a third lens, a fourth lens, and a fifth lens, which are arranged in order from left to right along the incident optical path of the light. The first lens is a negative meniscus lens, whose object-side surface is convex and whose image-side surface is concave. The second lens is a biconvex positive lens, whose object-side surface is convex and whose image-side surface is convex. The third lens is a biconvex positive lens, whose object-side surface is convex and whose image-side surface is convex. The fourth lens is a biconcave negative lens, whose object-side surface is concave and whose image-side surface is concave. The fifth lens is a biconvex positive lens, whose object-side surface is convex and whose image-side surface is convex. 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, and the fifth lens are f1, f2, f3, f4, f5 respectively. 5， Among them, f1, f2, f3, f4, f5 and f satisfy the following ratio: -2.0 <f1 / f<-1.0,1.0<f2 / f<2.0,1.0<f3 / f<2.0,-1.0<f4 / f<0.0,1.0<f5 / f<2.0; The air gap between the first and second lenses is 6.0-6.5 mm; the aperture is located on the second lens, and the air gap between the aperture and the third lens is 0.5-1.0 mm; the third and fourth lenses are cemented lens groups, and the air gap is 0 mm; the air gap between the fourth and fifth lenses is 0.1-0.5 mm; The image height H of the optical system and the focal length f of the optical system satisfy: H / f≤1.0; The F number of the optical system is ≤1.6; Focal length: 6.0≤f≤7.0mm.

2. The 3M five-element front-view main camera 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 ≥50.0; the third lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the fourth lens satisfies the relationship: 1.8≤N d ≤2.0, V d ≤50.0; the fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

3. The 3M five-element front-view main camera according to claim 1, characterized in that: The first lens and the fifth lens are aspherical lenses, and the aspherical curve equation is expressed as: ； Among them, Z is the height of the aspheric surface from the vertex of the aspheric surface when it is at a height of r 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.

4. The 3M five-element front-view main camera 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: TTL / f≤5.

0.

5. The 3M five-element front-view main camera according to claim 1, characterized in that: A first equivalent glass plate, a second equivalent glass plate and an imaging surface are sequentially arranged on the rear side of the fifth lens.

6. An imaging method using the 3M five-element front-view main camera according to any one of claims 1 to 5, characterized in that: When light is incident, the light path enters the first lens, the second lens, the aperture, the third lens, the fourth lens and the fifth lens in sequence to form an image.

Images