Low-cost foresight main camera and imaging method thereof

Abstract

The invention relates to a low-cost foresight main camera and an imaging method thereof, an optical system of the main camera has six lenses with focal power, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens are sequentially arranged along the incident direction of an optical path, and a diaphragm is arranged between the third lens and the fourth lens; the first lens is a meniscus negative lens, the object side surface is a convex surface, and the image side surface is a concave surface; the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the third lens is a biconvex positive lens; the fourth lens is a biconvex positive lens; the fifth lens is a meniscus negative lens, the object side surface is a concave surface, and the image side surface is a convex surface; the sixth lens is a biconvex positive lens; the first lens and the third lens are glass spherical lenses, the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspheric lenses, and the fourth lens and the fifth lens form a balsaming lens group.

Description

Technical Field

[0001] This invention relates to the field of lens technology, and in particular to a low-cost front-view main camera and its imaging method. Background Technology

[0002] Since the beginning of the 21st century, people's demands for automobiles have gone beyond just more powerful performance, a more comfortable driving experience, and more reliable safety. With the development of technologies such as electronics, artificial intelligence, and 5G, as well as industrial design and manufacturing capabilities, intelligentization has become an inevitable trend in the automotive industry. In particular, intelligent vehicle technologies, represented by autonomous driving, ADAS, and smart cockpits, have become a technological high ground that major technology companies are vying to conquer.

[0003] The forward-facing camera mounted on the windshield is mainly used for visual perception and recognition functions while driving. Based on function, it can be divided into a main forward-facing camera, a narrow-angle forward-facing camera, and a wide-angle forward-facing camera. However, using three cameras significantly increases the cost of the entire camera module, hindering market adoption. Therefore, a wide-angle lens is used to create a single-lens forward-facing camera module. However, to achieve the desired optical performance (wide angle, high image quality, large aperture, low temperature drift), multiple glass elements are often required, further increasing costs. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a low-cost forward-looking main camera and its imaging method, which ensures high imaging quality even at large angles, while greatly reducing costs and ensuring lens miniaturization.

[0005] This invention is implemented using the following scheme: a low-cost front-view main camera, wherein the optical system of the main camera has 6 lenses with optical power, arranged sequentially along the incident direction of the light path as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, with an aperture stop between the third lens and the fourth lens; the first lens is a meniscus negative lens with a convex object side and a concave image side; the second lens is a meniscus negative lens with a concave object side and a convex image side; the third lens is a biconvex positive lens; the fourth lens is a biconvex positive lens; the fifth lens is a meniscus negative lens with a concave object side and a convex image side; the sixth lens is a biconvex positive lens; the first and third lenses are glass spherical lenses, and the second, fourth, fifth, and sixth lenses are plastic aspherical lenses, wherein the fourth and fifth lenses constitute a cemented lens group.

[0006] Furthermore, the focal length of the optical system is f, and the focal lengths of the first, second, third, fourth, fifth, and sixth lenses 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,-5.0<f2 / f<-4.0,1.0<f3 / f<2.0,1.0<f4 / f<2.0,-2.0<f5 / f<-1.0,4.0<f6 / f<5.0。

[0007] Furthermore, the first lens satisfies the relationship: 1.7 ≤ N d ≤2.0, 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: 1.7≤N d ≤2.0, 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: 1.5≤N d ≤1.8, V d ≤50.0; The sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; where N d V is the refractive index. d Let be Abbe's constant.

[0008] Furthermore, the air gap between the first lens and the second lens is 3.5~4.0mm; the air gap between the second lens and the third lens is 0.1~0.5mm; the air gap between the third lens and the aperture stop is 0.1~0.5mm; the air gap between the aperture stop and the fourth lens is 0.1~0.5mm; the fourth lens and the fifth lens form a cemented lens group with an air gap of 0mm; and the air gap between the fifth lens and the sixth lens is 0.1~0.5mm.

[0009] Furthermore, the total optical length (TTL) of the optical system and the focal length (f) of the optical system satisfy the following condition: TTL / f ≤ 6.0.

[0010] Furthermore, the F-number of the optical system is ≤1.6.

[0011] Furthermore, the image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f ≥ 1.0.

[0012] Furthermore, a filter is provided on the rear side of the sixth lens.

[0013] Another technical solution of the present invention: an imaging method for a low-cost front-view main camera as described above, wherein light passes sequentially through a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens, and a filter before forming an image.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) The lens has an imaging angle of more than 130 degrees for objects, and has advantages such as high imaging clarity, large light aperture, low tolerance sensitivity and good high and low temperature stability. It can also monitor the outside scene of the vehicle more comprehensively. (2) By reasonably matching the optical lenses, the system structure is compact and reasonable, easy to assemble, has low tolerance sensitivity, and is more suitable for large-scale high-yield production; (3) The optical structure of glass-plastic hybrid is adopted, which consists of two glass spherical lenses and four plastic aspherical lenses. This fully utilizes the advantages of aspherical lenses in correcting aberrations, meets the requirements of high-definition imaging, and has a smaller lens outer diameter and shorter overall optical length, thus ensuring the miniaturization of the lens. (4) It can compensate for focal plane displacement at high and low temperatures and has adaptability to complex environments; (5) The chromatic aberration along each axis, the vertical axis, and the higher-order chromatic aberrations have been corrected to ensure that the imaging system can have high imaging quality even at large angles.

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through specific embodiments and related drawings. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the optical system structure according to an embodiment of the present invention; Figure 2 This is an axial chromatic aberration diagram of the optical system across the entire operating band according to an embodiment of the present invention; Figure 3 This is a transverse chromatic aberration diagram of the optical system across the entire operating band according to an embodiment of the present invention; Figure 4 This is a field curvature distortion diagram of the optical system across all operating wavelengths according to an embodiment of the present invention; In the diagram: STO - aperture stop; 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 plane. Detailed Implementation

[0017] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, 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 pertains.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] like Figure 1 As shown, a low-cost front-view main camera has an optical system with six lenses of optical power, arranged sequentially along the incident light path as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. An aperture stop is provided between the third and fourth lenses. Ignoring the curvature caused by aspherical coefficients, the first lens is a meniscus negative lens with a convex object-side and a concave image-side; the second lens is a meniscus negative lens with a concave object-side and a convex image-side; the third lens is a biconvex positive lens with a convex object-side and a convex image-side; the fourth lens is a biconvex positive lens with a convex object-side and a convex image-side; the fifth lens is a meniscus negative lens with a concave object-side and a convex image-side; and the sixth lens is a biconvex positive lens with a convex object-side and a convex image-side. The first and third lenses are glass spherical lenses, while the second, fourth, fifth, and sixth lenses are plastic aspherical lenses, with the fourth and fifth lenses forming a cemented lens group.

[0020] The first and second lenses are negative power lenses capable of adjusting large-angle light, and their plastic aspherical surfaces also reduce optical system distortion. The fourth and fifth lenses form an achromatic cemented doublet. This reasonable lens combination enables the optical system to achieve low cost, high resolution, a 130° wide-angle lens, large aperture, day and night confocal focus, and low temperature drift design. It also provides good correction for on-axis and off-axis aberrations, resulting in good image quality. Figures 2 to 4 As shown.

[0021] In this embodiment, 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, wherein f1, f2, f3, f4, f5, and f6 satisfy the following ratio with f: -2.0 <f1 / f<-1.0,-5.0<f2 / f<-4.0,1.0<f3 / f<2.0,1.0<f4 / f<2.0,-2.0<f5 / f<-1.0,4.0<f6 / f<5.0。

[0022] In this embodiment, the first lens satisfies the relationship: 1.7 ≤ N d ≤2.0, 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: 1.7≤N d ≤2.0, 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: 1.5≤N d ≤1.8, V d ≤50.0; The sixth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; where N d V is the refractive index. d Let be Abbe's constant.

[0023] In this embodiment, the air gap between the first lens and the second lens is 3.5~4.0mm; the air gap between the second lens and the third lens is 0.1~0.5mm; the air gap between the third lens and the aperture stop is 0.1~0.5mm; the air gap between the aperture stop and the fourth lens is 0.1~0.5mm; the fourth lens and the fifth lens form a cemented lens group with an air gap of 0mm; and the air gap between the fifth lens and the sixth lens is 0.1~0.5mm.

[0024] In this embodiment, the second, fourth, fifth, and sixth lenses are all aspherical lenses. The equation for the aspherical curve is: Where Z is the distance from the vertex of the aspherical surface to the optical axis at a position of height r; c is the paraxial curvature of the aspherical surface; and k is the conic constant. All are coefficients of higher-order terms.

[0025] The aspherical coefficients of the aspherical lenses in the optical system of this embodiment are shown in the table below:

[0026] In this embodiment, the total optical length (TTL) of the optical system and the focal length (f) of the optical system satisfy the following condition: TTL / f ≤ 6.0.

[0027] In this embodiment, the F-number of the optical system is ≤1.6.

[0028] In this embodiment, the image height H of the optical system and the focal length f of the optical system satisfy the following condition: H / f≥1.0.

[0029] In this embodiment, a filter is provided on the rear side of the sixth lens.

[0030] The technical specifications achieved by the optical system in this embodiment are as follows: (1) Focal length: 3.0≤EFFL≤4.0mm; (2) Aperture F≤1.6; (3) Field of view: 2w ≥ 130°; (4) Operating band: Visible light band.

[0031] To achieve the above design parameters, the specific design of the optical system adopted in this embodiment is shown in the table below:

[0032] The optical system of this invention achieves low-cost 130° wide-angle imaging performance by rationally allocating the optical power, surface shape, center thickness of each lens, and on-axis distance between each lens, thus realizing the visual perception and recognition function of the vehicle. It can replace the front-view wide-angle camera and the front-view narrow-angle camera, realize the formation of a front-view camera module by a single lens, greatly reduce the cost to improve market penetration, reduce the total length of the lens and the radial size of each lens, and achieve miniaturization of the lens group.

[0033] An imaging method for a low-cost front-view main camera as described above, wherein light sequentially passes through a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens, and a filter before forming an image.

[0034] Unless otherwise stated, if any of the technical solutions disclosed in this invention specify a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0035] If this invention discloses or relates to mutually fixedly connected components or structural parts, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0036] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0037] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A low cost front-facing primary camera, characterized by: The optical system of the main camera has six lenses with optical power, which are sequentially a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens along the incident direction of the optical path, and a diaphragm is arranged between the third lens and the fourth lens; the first lens is a meniscus 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 negative lens, the object side surface of which is concave, and the image side surface of which is convex; the third lens is a biconvex positive lens; the fourth lens is a biconvex positive lens; the fifth lens is a meniscus negative lens, the object side surface of which is concave, and the image side surface of which is convex; and the sixth lens is a biconvex positive lens; the first lens and the third lens are glass spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens are plastic aspherical lenses, wherein the fourth lens and the fifth lens constitute a cemented lens group.

2. The low cost front-facing primary camera of claim 1, wherein: 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, -5.0 < f2 / f < -4.0, 1.0 < f3 / f < 2.0, 1.0 < f4 / f < 2.0, -2.0 < f5 / f < -1.0, and 4.0 < f6 / f < 5.

0.

3. The low cost front-facing primary camera of claim 1, wherein: The first lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, 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: 1.7 ≤ N d ≤ 2.0, 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: 1.5 ≤ N d ≤ 1.8, V d ≤ 50.0; the sixth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

4. The low cost front-facing primary camera of claim 1, wherein: 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 third lens is 0.1-0.5 mm; the air gap between the third lens and the diaphragm is 0.1-0.5 mm; the air gap between the diaphragm and the fourth lens is 0.1-0.5 mm; the fourth lens and the fifth lens constitute a cemented lens group, and the air gap is 0 mm; and the air gap between the fifth lens and the sixth lens is 0.1-0.5 mm.

5. The low cost front-facing primary camera of claim 1, wherein: The total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f ≤ 6.

0.

6. The low cost front-facing primary camera of claim 1, wherein: The F number of the optical system is ≤1.

6.

7. The low cost front-facing primary 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.

8. The low cost front-facing primary camera of claim 1, wherein: The rear side of the sixth lens is provided with a filter.

9. The method of imaging of a low cost forward looking primary camera as claimed in claim 8, wherein: Light rays are sequentially imaged through the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the filter.

Images