8m front-view main camera and imaging method thereof

Abstract

The application relates to an 8M front-view main camera and an imaging method thereof, which comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence from left to right along a light path of light incidence; the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a double-convex positive lens, the fourth lens is a double-convex positive lens, the fifth lens is a double-convex positive lens, the sixth lens is a double-concave negative lens, and the seventh lens is a double-convex positive lens. The application has reasonable design and simple structure, and through reasonable distribution of optical power, surface type, center thickness of each lens and axial distance between the lenses, the total length of the lens and the radial size of each lens are reduced while the imaging performance of the lens meets the requirements of the front-view wide-angle camera and the front-view narrow-angle camera, so that the lens group is miniaturized.

Description

TECHNICAL FIELD

[0001] The application relates to an 8M front-view main camera and an imaging method thereof. BACKGROUND

[0002] With the development of economy and the improvement of people's living quality, the annual sales of automobiles in China exceed 10 million. With the increase of the number of automobiles in cities, roads become more and more crowded, and the problem of frequent traffic accidents is increasingly prominent. In order to reduce the occurrence of traffic accidents and protect the safety of life and property, people are more willing to buy automobiles containing automobile safety technology when purchasing automobiles. Automobile safety technology includes lane departure warning, active collision avoidance, adaptive cruise control, traction control, etc. The vehicle-mounted front-view camera system is an automobile safety technology with a lane departure warning function, and the vehicle-mounted front-view camera module plays an important role as the hardware terminal of the system. The front-view camera is mainly installed on the front windshield and is used to realize the visual perception and recognition function of driving, and can be divided into a front-view main camera, a front-view narrow-angle camera and a front-view wide-angle camera according to the function.

[0003] However, the adoption of the three cameras greatly increases the cost of the entire camera module, which is not conducive to market popularization. The function of the front-view wide-angle camera is mainly to recognize objects at a relatively close distance, and it is mainly used in urban road working conditions, low-speed driving and other scenes, and the field of view is 120 DEG to 150 DEG, and the detection distance is about 50 m. Therefore, if an 8MP lens is adopted on a large scale, the front-view wide-angle camera can be dispensed with. SUMMARY

[0004] The application improves the above problems, that is, the technical problem to be solved by the application is to provide an 8M front-view main camera and an imaging method thereof, which realize the visual perception and recognition function of driving and 8MP imaging, so as to replace the front-view wide-angle camera and the front-view narrow-angle camera, realize a single-lens front-view camera module, greatly reduce the cost and improve the market popularization.

[0005] The application is constituted as follows: it comprises a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are arranged in sequence from left to right along the light path of light incidence; the first lens is a meniscus concave negative lens, the object side is a convex surface, and the image side is a concave surface; the second lens is a meniscus concave negative lens, the object side is a convex surface, and the image side is a concave surface; the third lens is a double-convex positive lens, the object side is a convex surface, and the image side is a convex surface; the fourth lens is a double-convex positive lens, the object side is a convex surface, and the image side is a convex surface; the fifth lens is a double-convex positive lens, the object side is a convex surface, and the image side is a convex surface; the sixth lens is a double-concave negative lens, the object side is a concave surface, and the image side is a concave surface; and the seventh lens is a double-convex positive lens, the object side is a convex surface, and the image side is a convex surface.

[0006] Further, the first, second, third, and seventh lenses are glass aspherical lenses, and the fourth, fifth, and sixth lenses are glass spherical lenses, wherein the fifth and sixth lenses are cemented lens groups.

[0007] Further, the focal length of the optical system is f, and the focal lengths of the first, second, third, fourth, fifth, sixth, and seventh lenses are f1, f2, f3, f4, f5, f6, and f7, respectively, wherein f1, f2, f3, f4, f5, f6, and f7 satisfy the following ratios with respect to f: -3.0 < f1 / f < -2.0, -327.0 < f2 / f < -326.0, 2.0 < f3 / f < 3.0, 1.0 < f4 / f < 2.0, 1.0 < f5 / f < 2.0, -1.0 < f6 / f < 0.0, and 1.0 < f7 / f < 2.0.

[0008] Further, the first lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0 and V d ≤ 50.0; the second lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0 and V d ≤ 50.0; the third lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0 and V d ≤ 50.0; the fourth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0 and V d ≤ 50.0; the fifth lens satisfies the relationship: 1.5 ≤ N d ≤ 1.8 and V d ≥ 50.0; the sixth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0 and V d ≤ 50.0; and the seventh lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0 and V d ≤ 50.0; wherein N d is the refractive index and V d is the Abbe number.

[0009] Further, 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 2.5-3.0 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 air gap between the fourth lens and the fifth lens is 0.1-0.5 mm; the fifth and sixth lenses are cemented lens groups with an air gap of 0 mm; and the air gap between the sixth lens and the seventh lens is 0.5-1.0 mm.

[0010] Further, the first lens, the second lens, the third lens and the seventh lens are aspherical lenses, and an aspherical curve equation expression is:

[0011] ;

[0012] wherein Z is the sag 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 alpha1, alpha2, alpha3, alpha4, alpha5, alpha6, alpha7 and alpha8 are high-order coefficients.

[0013] Further, the rear side of the seventh lens is sequentially provided with a first equivalent glass flat plate, a second equivalent glass flat plate and an imaging surface.

[0014] Further, the total optical length TTL of the optical system and the focal length f of the optical system satisfy TTL / f≤5.0.

[0015] Further, the image height H of the optical system and the focal length f of the optical system satisfy H / f≤1.0.

[0016] Further, the F number of the optical system is ≤1.6.

[0017] Further, the imaging method of the 8M front-view main camera is as follows: when light is incident, the light path sequentially enters the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens to perform imaging.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1. The lens has an imaging angle of more than 167 degrees for an object, and has the advantages of super-high 8M imaging clarity, large light aperture, low tolerance sensitivity and good high-low temperature stability, etc. Meanwhile, the lens can more comprehensively monitor the scene outside the vehicle; 2. By reasonably matching the optical lenses, the system structure is compact and reasonable, easy to assemble, low in tolerance sensitivity, and more suitable for large-scale high-yield production; 3. The all-glass structure has high stability, can adapt to harsh environments, fully utilizes the advantages of aspherical lenses in correcting aberrations, meets the requirements of high-definition imaging, has a smaller lens outer diameter and shorter total optical length, and ensures the miniaturization of the lens; 4. The lens can make good compensation for the displacement of the focusing surface at high and low temperatures, and has adaptability to complex environments; 5. The lens corrects the axial color difference, the vertical axis color difference and the high-order color difference, and ensures that the imaging system also has high imaging quality at a large angle. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic diagram of the optical structure of an embodiment of the present application;

[0021] Figure 2 This is an axial chromatic aberration diagram of the entire working band of this invention.

[0022] Figure 3 This is a transverse chromatic aberration diagram of the entire working band of this invention;

[0023] Figure 4 This is a field curvature distortion diagram of the entire working band of this invention embodiment;

[0024] In the diagram: L1 - First lens; L2 - Second lens; L3 - Third lens; L4 - Fourth lens; L5 - Fifth lens; L6 - Sixth lens; L7 - Seventh lens; L8 - First equivalent glass plate; L9 - Second equivalent glass plate; IMA - Imaging plane; STO - Aperture stop. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] Example: Figures 1-4 As shown, the present invention provides an 8M front-view main camera, including a first lens L1, a second lens L2, a third lens L3, an aperture STO, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged sequentially from left to right along the incident light path; the first lens is a meniscus negative lens, with its object side being convex and its image side being concave.

[0027] Without considering the curvature caused by the aspherical coefficient, the second lens is a meniscus negative lens with a convex object side and a concave 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 biconvex positive lens with a convex object side and a convex image side; the sixth lens is a biconcave negative lens with a concave object side and a concave image side; and the seventh lens is a biconvex positive lens with a convex object side and a convex image side.

[0028] The first, second, third, and seventh lenses mentioned above are aspherical glass lenses, while the fourth, fifth, and sixth lenses are spherical glass lenses. The fifth and sixth lenses are a cemented lens group. The first and second lenses are both aspherical glass lenses, which reduce optical system distortion. The aspherical glass lens with negative optical power can adjust light at large angles. The fifth and sixth lenses form an achromatic cemented doublet. Through this reasonable lens combination, the optical system achieves an 8M aperture, ultra-wide angle, large aperture, day / 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.

[0029] In the embodiment of the present application, 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, 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 ratios: -3.0 < f1 / f < -2.0, -327.0 < f2 / f < -326.0, 2.0 < f3 / f < 3.0, 1.0 < f4 / f < 2.0, 1.0 < f5 / f < 2.0, -1.0 < f6 / f < 0.0, and 1.0 < f7 / f < 2.0.

[0030] In the embodiment of the present application, the first lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, 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: 1.7 ≤ N d ≤ 2.0, 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: 1.5 ≤ N d ≤ 1.8, V d ≥ 50.0; the sixth lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; and the seventh lens satisfies the relationship: 1.7 ≤ N d ≤ 2.0, V d ≤ 50.0; wherein N d is the refractive index, and V d is the Abbe number.

[0031] In the embodiment of the present application, 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 2.5-3.0 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 air gap between the fourth lens and the fifth lens is 0.1-0.5 mm; the fifth lens and the sixth lens are cemented lens groups, and the air gap is 0 mm; and the air gap between the sixth lens and the seventh lens is 0.5-1.0 mm.

[0032] In the embodiment of the present application, the first lens, the second lens, the third lens and the seventh lens are aspherical lenses, and the aspherical curve equation expression is:

[0033] ;

[0034] Wherein, Z is the sag of the aspheric surface at a position with a height of r along the optical axis direction from the vertex of the aspheric surface; c is the paraxial curvature of the aspheric surface; k is the conic constant; and alpha1, alpha2, alpha3, alpha4, alpha5, alpha6, alpha7 and alpha8 are high-order coefficients.

[0035] In the embodiment of the present application, the back side of the seventh lens is sequentially provided with a first equivalent glass flat plate L8, a second equivalent glass flat plate L9 and an imaging surface IMA.

[0036] In the embodiment of the present application, the total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤5.0.

[0037] 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.

[0038] In the embodiment of the present application, the F number of the optical system is ≤1.6.

[0039] In the embodiment of the present application, during imaging: when the light is incident, the light path enters the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens in sequence to perform imaging.

[0040] The technical indexes realized by the optical system in the embodiment of the present application are as follows: (1) focal length: 4.0≤EFFL≤5.0 mm; (2) aperture F≤1.6; (3) field of view angle: 2w≥167°; and (4) working waveband: visible light waveband.

[0041] To realize the above design parameters, the specific design parameters of the optical system in the embodiment of the present application are shown in Table 1 below:

[0042]

[0043] Table 1

[0044] The aspheric coefficients of each aspheric lens of the optical system in the embodiment of the present application are shown in Table 2 below:

[0045]

[0046] Table 2

[0047] In the embodiment of the present application, the optical system reasonably allocates the optical power, surface type, central thickness of each lens and the axial distance between each lens, etc., so as to meet the 8M imaging performance requirements 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.

[0048] Any of the technical solutions disclosed in the present application above, if not otherwise stated, 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 only one of the many implementable numerical values with more obvious technical effects or representative values. Because there are too many values, it is impossible to enumerate them all, so the present application discloses some values to illustrate the technical solutions of the present application, and the above-mentioned enumerated values should not constitute a limitation on the protection scope of the present application.

[0049] At the same time, if the above-mentioned present application discloses or involves mutually fixed connecting parts or structural parts, except otherwise stated, the fixed connection can be understood as: detachable fixed connection (for example, using bolt or screw connection), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, using casting process to make an integral shape) (except for obvious cases that cannot use integral forming process).

[0050] If the words "first", "second" and the like are used herein to limit the parts, those skilled in the art should know that the use of "first", "second" is only for the convenience of describing the parts to distinguish them, and the above words have no special meaning unless otherwise stated.

[0051] In addition, the terms used to represent the position relationship or shape in any of the technical solutions disclosed in the above-mentioned present application include the approximate, similar or close state or shape unless otherwise stated.

[0052] Any of the components provided by the present application can be assembled from multiple individual components, or can be a single component manufactured by an integral forming process.

[0053] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent ones; without departing from the spirit of the technical solutions of the present application, they should all be covered in the technical solution range of the present application claimed.

Claims

1. An 8M front-facing primary camera, characterized by, The first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens are sequentially arranged along the light path of the incident light from left to right; the first lens is a meniscus concave negative lens, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; the second lens is a meniscus concave negative lens, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; the third lens is a double-convex positive lens, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; the fourth lens is a double-convex positive lens, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; the fifth lens is a double-convex positive lens, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; the sixth lens is a double-concave negative lens, the object side surface of which is a concave surface, and the image side surface of which is a concave surface; and the seventh lens is a double-convex positive lens, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; The first lens, the second lens, the third lens and the seventh lens are aspherical lenses, and the fourth lens, the fifth lens and the sixth lens are spherical lenses; the fifth lens and the sixth lens are cemented lens groups. 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, 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 ratios: -3.0 < f1 / f < -2.0, -327.0 < f2 / f < -326.0, 2.0 < f3 / f < 3.0, 1.0 < f4 / f < 2.0, 1.0 < f5 / f < 2.0, -1.0 < f6 / f < 0.0, and 1.0 < f7 / f < 2.

0.

2. The 8M front-facing primary camera of claim 1, wherein, The first lens satisfies the relationship: N d = 1.77, V d = 49.59; the second lens satisfies the relationship: N d = 1.81, V d = 41.00; the third lens satisfies the relationship: N d = 1.85, V d = 40.12; the fourth lens satisfies the relationship: N d = 1.95, V d = 32.32; the fifth lens satisfies the relationship: N d = 1.59, V d = 68.62; the sixth lens satisfies the relationship: N d = 1.95, V d = 17.94; the seventh lens satisfies the relationship: N d = 1.81, V d = 41.00; wherein N d is the refractive index and V d is the Abbe number.

3. The 8M front-facing primary camera of claim 1, wherein, The air gap between the first lens and the second lens is 2.171 mm; the air gap between the second lens and the third lens is 2.969 mm; the air gap between the third lens and the diaphragm is 0.166 mm; the air gap between the diaphragm and the fourth lens is 0.124 mm; the air gap between the fourth lens and the fifth lens is 0.161 mm; the air gap between the fifth lens and the sixth lens is 0 mm; and the air gap between the sixth lens and the seventh lens is 0.613 mm.

4. The 8M front-facing primary camera of claim 1, wherein, The first lens, the second lens, the third lens and the seventh lens are aspherical lenses, and the fourth lens, the fifth lens and the sixth lens are spherical lenses; the fifth lens and the sixth lens are cemented lens groups. ； The rear side of the seventh lens is sequentially provided with a first equivalent glass flat plate, a second equivalent glass flat plate and an imaging surface.

5. The 8M front-facing primary camera of claim 1, wherein, The F number of the optical system is less than or equal to 1.

6.

6. An 8M front-facing primary camera according to claim 1, wherein, When the light is incident, the light path sequentially enters the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens to form an image.

7. An imaging method using the 8M forward-looking main camera according to any one of claims 1-6, characterized in that, ​

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