A front-view lens suitable for a vehicle-mounted binocular camera module and an imaging method thereof

Abstract

The application relates to a front-view lens suitable for a vehicle-mounted binocular camera module and an imaging method thereof, characterized by comprising a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged in the light incidence direction of the lens structure and are glued into a lens group, the imaging angle of the object is greater than 140 degrees, meanwhile, the lens has the advantages of high imaging definition, large light aperture, low tolerance sensitivity, good high-low temperature stability and the like, the front view of the vehicle can be more comprehensively monitored, the system structure is compact and reasonable, each axial chromatic aberration, vertical axial chromatic aberration and high-order chromatic aberration are corrected, and the imaging system can also have high imaging quality at a large angle.

Description

Technical Field

[0001] The present invention relates to a front-view lens suitable for a vehicle-mounted binocular camera module and an imaging method thereof. Background Art

[0002] With economic development and improved living standards, my country's annual automobile sales exceed 10 million. As the number of cars in cities increases, roads become increasingly congested, and traffic accidents are becoming increasingly common. To reduce the risk of traffic accidents and protect their lives and property, people are increasingly interested in vehicles equipped with safety technologies. In-vehicle forward-view camera modules, as the hardware terminals of these systems, play a crucial role.

[0003] Automotive forward-view camera modules are generally divided into two types: monocular and binocular. Monocular camera modules offer lower costs and perform well when used in conjunction with radar systems. Binocular camera modules also have their advantages, such as the fixed spacing between their two lenses, which enables more accurate distance measurement. Currently, the main challenges with binocular camera modules are high cost, complex systems, and difficulty miniaturizing them. Summary of the Invention

[0004] The present invention provides a front-view lens suitable for an on-vehicle binocular camera module and an imaging method thereof, which achieves clear imaging while having a small external size.

[0005] The solution adopted by the present invention to solve the technical problem is a forward-looking lens suitable for a vehicle-mounted binocular camera module: it includes a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence along the incident direction of light in the lens structure, and the third lens and the fourth lens are glued together to form a lens group.

[0006] Furthermore, 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 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 meniscus concave negative lens, whose object side surface is concave and whose image side surface is convex; the fifth lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the sixth lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave.

[0007] Furthermore, the first lens, the second lens, the aperture, the third lens, the fourth lens, the fifth lens and the sixth lens are made of glass material, the first lens and the sixth lens are aspherical lenses, and the second lens, the third lens, the fourth lens and the fifth lens are spherical lenses.

[0008] 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, the fifth lens, and the sixth lens are f1, f2, f3, f4, f5, and f6, respectively, where f1, f2, f3, f4, f5, and f6 satisfy the following ratio with f: -2.0 <f1 / f<-1.0,1.0<f2 / f<2.0,1.0<f3 / f<2.0,-2.0<f4 / f<-1.0,2.0<f5 / f<3.0,-3.0<f6 / f<-2.0。

[0009] Furthermore, the first lens satisfies the relationship: 1.5≤N d ≤1.8, 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: 1.7≤N d ≤2.0, V d ≤50.0; the fifth lens satisfies the relationship: 1.2≤N d ≤1.5, V d ≥50.0; the sixth 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.

[0010] Furthermore, the air gap between the first lens and the second lens is 3.5 to 4.0 mm; the air gap between the second lens and the aperture is 0.1 to 0.5 mm; the air gap between the aperture and the third lens is 1.0 to 1.5 mm; the air gap between the fourth lens and the fifth lens is 2.1 to 2.5 mm; and the air gap between the fifth lens and the sixth lens is 0.1 to 0.5 mm.

[0011] Furthermore, the aspheric curve equations of the first lens and the sixth lens are expressed as follows:

[0012]

[0013] 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·α8 are all high-order coefficients.

[0014] Furthermore, the total optical length TTL of the overall optical lens and the focal length f of the optical system satisfy: TTL / f≤4.5.

[0015] Furthermore, the F number of the overall optical lens is ≤1.5, and the image height H of the overall optical lens and the focal length f of the optical system satisfy: H / f≤1.0.

[0016] An imaging method for a front-view lens of a vehicle-mounted binocular camera module: when light is incident, the light path sequentially enters a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, and a sixth lens, and finally forms an image on an image plane.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The lens has an imaging angle of more than 140 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 in front of the vehicle more comprehensively.

[0019] 2. Through the reasonable combination of optical lenses, the system structure is compact and reasonable, the overall volume is reduced, the assembly is easy, the tolerance sensitivity is low, and it is more suitable for large-scale high-yield production;

[0020] 3. The all-glass lens structure can compensate for focal plane displacement at high and low temperatures, and has high adaptability to complex environments;

[0021] 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. 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: STO-aperture; L1-first lens; L2-second lens; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-equivalent glass plate; 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 specific embodiments.

[0028] like Figure 1-4 As shown, a front-view lens suitable for an on-vehicle binocular camera module includes a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence along the incident direction of light within a lens structure. The third lens and the fourth lens are cemented together to form a lens group. The reasonable lens combination enables the optical system to achieve a design that is extremely small in size, wide-angle, large in aperture, day and night confocal, and low in temperature. At the same time, on-axis and off-axis aberrations are well corrected, resulting in good imaging quality.

[0029] In this embodiment, the first lens is a meniscus concave negative lens with a convex object-side surface and a concave image-side surface; the second lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; 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 meniscus concave negative lens with a concave object-side surface and a convex image-side surface; the fifth lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface; and the sixth lens is a meniscus concave negative lens with a convex object-side surface and a concave image-side surface.

[0030] In this embodiment, the first lens, the second lens, the aperture, the third lens, the fourth lens, the fifth lens, and the sixth lens are made of glass materials. The first lens and the sixth lens are aspherical lenses, and the second lens, the third lens, the fourth lens, and the fifth lens are spherical lenses.

[0031] In this 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, where f1, f2, f3, f4, f5, and f6 satisfy the following ratio with f: -2.0 <f1 / f<-1.0,1.0<f2 / f<2.0,1.0<f3 / f<2.0,-2.0<f4 / f<-1.0,2.0<f5 / f<3.0,-3.0<f6 / f<-2.0。

[0032] In this embodiment, the first lens satisfies the relationship: 1.5≤N d ≤1.8, 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: 1.7≤N d ≤2.0, V d≤50.0; the fifth lens satisfies the relationship: 1.2≤N d ≤1.5, V d ≥50.0; the sixth 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.

[0033] In this embodiment, the air gap between the first lens and the second lens is 3.5-4.0 mm; the air gap between the second lens and the aperture is 0.1-0.5 mm; the air gap between the aperture and the third lens is 1.0-1.5 mm; the air gap between the fourth lens and the fifth lens is 2.1-2.5 mm; and the air gap between the fifth lens and the sixth lens is 0.1-0.5 mm.

[0034] In this embodiment, the aspheric curve equations of the first lens and the sixth lens are expressed as follows:

[0035]

[0036] 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·α8 are all high-order coefficients.

[0037] In this embodiment, a filter is provided on the rear side of the fourth lens.

[0038] In this embodiment, the total optical length TTL of the integral optical lens and the focal length f of the optical system satisfy the following relationship: TTL / f≤4.5.

[0039] In this embodiment, the F number of the overall optical lens is ≤1.5, and the image height H of the overall optical lens and the focal length f of the optical system satisfy: H / f≤1.0.

[0040] An imaging method for a front-view lens of a vehicle-mounted binocular camera module: when light is incident, the light path sequentially enters a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, and a sixth lens, and finally forms an image on an image plane.

[0041] The technical indicators achieved by the optical system of this embodiment are as follows:

[0042] Focal length: 4.0 ≤ EFFL ≤ 5.0 mm;

[0043] Aperture F≤1.5;

[0044] Field of view: 2w ≥ 140°;

[0045] Working band: visible light 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 achieves miniaturization of the lens group by reasonably allocating the optical focal length, surface shape, center thickness of each lens, and axial distance between lenses, thereby meeting the imaging performance requirements of the lens while reducing the total length of the lens and the radial dimensions of each lens.

[0052] 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.

[0053] 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.

[0054] If the present 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, connection using bolts or screws), 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 integrated molding using a casting process) (except where it is obviously impossible to use an integrated molding process).

[0055] In addition, the orientations or positional relationships indicated by terms such as "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", and "outside" used in any of the technical solutions disclosed in the above invention are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing this patent, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this patent. Unless otherwise stated, the terms used to indicate shapes used in any of the technical solutions disclosed in the above invention include shapes that are approximate, similar, or close to them.

[0056] 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.

[0057] 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 front-view lens suitable for a vehicle-mounted binocular camera module, characterized by: The optical system of the lens 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 sequence along the incident direction of light. The third lens and the fourth lens form a cemented lens group. The first lens is a negative meniscus concave lens with a convex object-side surface and a concave image-side surface. The second lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface. 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 negative meniscus concave lens with a concave object-side surface and a convex image-side surface. The fifth lens is a biconvex positive lens with a convex object-side surface and a convex image-side surface. The sixth lens is a negative meniscus concave lens with a convex object-side surface and a concave image-side surface. The focal length of the optical system is f, and the focal lengths of the first lens, second lens, third lens, fourth lens, fifth lens, and sixth lens are f1, f2, f3, f4, f5, and f6 respectively, where f1, f2, f3, f4, f5, and f6 satisfy the following ratio with f: -2.0 <f1 / f<-1.0,1.0<f2 / f<2.0,1.0<f3 / f<2.0,-2.0<f4 / f<-1.0,2.0<f5 / f<3.0,-3.0<f6 / f<-2.0; The total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤4.

5.

2. The front-view lens for a vehicle-mounted binocular camera module according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are made of glass material. The first lens and the sixth lens are aspherical lenses, and the second lens, the third lens, the fourth lens and the fifth lens are spherical lenses.

3. The front-view lens for a vehicle-mounted binocular camera module according to claim 2, 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: 1.7≤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: 1.7≤N d ≤2.0, V d ≤50.0; the fifth lens satisfies the relationship: 1.2≤N d ≤1.5, V d ≥50.0; the sixth 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.

4. The front-view lens for a vehicle-mounted binocular camera module according to claim 3, characterized in that: The air gap between the first lens and the second lens is 3.5mm to 4.0mm; the air gap between the second lens and the aperture is 0.1mm to 0.5mm; the air gap between the aperture and the third lens is 1.0mm to 1.5mm; the air gap between the fourth lens and the fifth lens is 2.1mm to 2.5mm; and the air gap between the fifth lens and the sixth lens is 0.1mm to 0.5mm.

5. The front-view lens suitable for a vehicle-mounted binocular camera module according to claim 4, characterized in that: The aspheric curve equations of the first lens and the sixth lens are 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 h along the optical axis; c is the paraxial curvature of the aspheric surface; r = 1 / c; k is the cone constant; α1, α2, α3, α4, α5, α6, α7, and α8 are all high-order coefficients.

6. The front-view lens suitable for a vehicle-mounted binocular camera module according to claim 5, characterized in that: The F number of the optical system is ≤1.5, and the image height H of the optical system and the focal length f of the optical system satisfy: H / f ≤1.

0.

7. An imaging method for a front-view lens of a vehicle-mounted binocular camera module, using the front-view lens of a vehicle-mounted binocular camera module according to claim 6, characterized in that: When light is incident, it enters the first lens, the second lens, the aperture, the third lens, the fourth lens, the fifth lens and the sixth lens in sequence, and finally forms an image on the image plane.

Images