Low-cost 8m front-view main camera and imaging method

Abstract

The application relates to the technical field of lenses, in particular to a low-cost 8M front-view main camera and an imaging method, an optical system of the camera is composed of a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are arranged in sequence from left to right along a light incident path; wherein the fifth lens and the sixth lens are tightly formed into a cemented lens group; the first lens, the third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses, and the second lens and the seventh lens are aspherical lenses. The camera is small in size by reasonably distributing the optical power, surface type, central thickness of each lens and the axial distance between each lens, etc., while meeting the low-cost 8M super-wide-angle imaging performance of the camera to replace the requirements of a front-view wide-angle camera and a front-view narrow-angle camera, and reducing the total length of the camera and the radial size of each lens.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lenses, in particular to a low-cost 8M front-view main camera and an imaging method. BACKGROUND

[0002] With the development of the automobile industry and the increasing use requirements of users, more and more automobiles are provided with an automatic driving function in the production process. When the automatic driving function is used, a front-view camera plays a role in road recognition, obstacle detection and road sign recognition, and therefore the performance of the front-view camera is particularly important when the automatic driving function is actually used. The front-view camera installed on the front windshield is mainly 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, but the adoption of the three cameras greatly increases the cost of the entire camera module, which is not conducive to the popularization of the market. Therefore, an ultra-wide-angle 8MP lens is adopted to realize the single-lens composition of the front-view camera module, but in order to consider the optical performances such as the ultra-wide-angle, high image quality, large light aperture and low temperature drift, multiple glass pieces are often adopted, which increases the cost. SUMMARY

[0003] The application aims to provide a low-cost 8M front-view main camera and an imaging method, which can realize the visual perception and recognition function of driving and 8MP low-cost imaging, so as to replace the front-view wide-angle camera and the front-view narrow-angle camera, realize the single-lens composition of the front-view camera module, greatly reduce the cost and improve the market popularization.

[0004] The technical scheme of the application is as follows: a low-cost 8M front-view main camera, the optical system of the camera is composed of a first lens, a second lens, a third lens, a diaphragm, 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 incident path; without considering the reverse bending caused by the aspherical surface coefficient, 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 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; 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; 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 third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses, and the second lens and the seventh lens are aspherical lenses, wherein the fifth lens and the sixth lens are tightly connected to form a cemented lens group.

[0005] Further, the first lens, the third lens, the fourth lens, the fifth lens and the sixth lens are glass spherical lenses, and the second lens and the seventh lens are plastic aspherical lenses.

[0006] Further, the air gap between the first lens and the second lens is 2.5-3.0 mm, the air gap between the second lens and the third lens is 0.5-1.0 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 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 0.5-1.0 mm.

[0007] Further, the focal length of the optical system is , 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 , respectively. satisfy the following ratios: , , , , , , .

[0008] Further, the first lens satisfies the relationship: , ; the second lens satisfies the relationship: , ; the third lens satisfies the relationship: , ; the fourth lens satisfies the relationship: , ; the fifth lens satisfies the relationship: , ; the sixth lens satisfies the relationship: , ; and the seventh lens satisfies the relationship: , ; wherein is the refractive index, is the Abbe number.

[0009] Further, the optical total length TTL of the optical system and the focal length f of the optical system satisfy TTL / f≤10.0.

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

[0011] ​Further, the image height H of the optical system and the focal length f of the optical system satisfy: H / f >= 1.0.

[0012] Further, a filter is arranged on the right side of the seventh lens.

[0013] An imaging method of a low-cost 8M front-view main camera, light rays are sequentially arranged from left to right along the incident direction through the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens, and then imaged on the imaging surface.

[0014] Compared with the prior art, the present application has the following advantages:

[0015] 1. The imaging angle of the camera to the object is greater than 194 degrees, and at the same time, it has the advantages of super-high 8M imaging clarity, large light aperture, low tolerance sensitivity and good high-low temperature stability, etc. At the same time, it can more comprehensively monitor the scene outside the vehicle;

[0016] 2. By reasonably matching each optical lens, the system structure is compact and reasonable, easy to assemble, low tolerance sensitivity, and more suitable for large-scale high-yield production;

[0017] 3. The glass-plastic hybrid structure is adopted, which has low manufacturing cost and light weight, and is beneficial to the manufacturing and installation of the module;

[0018] 4. It can make good compensation for the focal plane displacement at high and low temperatures, and has complex environment adaptability;

[0019] 5. The axial color difference, sagittal color difference and high-order color difference are corrected, which ensures that the imaging system also has high imaging quality at a large angle.

[0020] 6. The advantages of aspheric lens in correcting aberration are fully utilized, which meets the requirements of high-definition imaging while having smaller lens outer diameter and shorter optical total length, ensuring the miniaturization of the camera. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 It is an optical structure schematic diagram of the present application;

[0022] Fig. 2 It is an axial color difference graph of the working waveband of the present application;

[0023] Fig. 3 It is a sagittal color difference graph of the full working waveband of the present application;

[0024] Fig. 4 It is a field curvature distortion graph of the full working waveband of the present application;

[0025] In the figure: STO - diaphragm; 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 flat plate; L9 - second equivalent glass flat plate; IMA - imaging plane. DETAILED DESCRIPTION

[0026] In order to make the above features and advantages of the present application more apparent, the following specific examples are described in detail below, with reference to the accompanying drawings, but the present application is not limited thereto.

[0027] Reference Figs. 1 to 4

[0028] A low-cost 8M front-view main camera, the optical system of the camera is composed of a first lens L1, a second lens L2, a third lens L3, a diaphragm STO, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 arranged in order from left to right along the light incident path; without considering the reverse bending caused by the aspherical 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 third lens is a double convex positive lens, the object side surface of which is convex, and the image side surface is convex; the fourth lens is a double convex positive lens, the object side surface of which is convex, and the image side surface is convex; the fifth lens is a double convex positive lens, the object side surface of which is convex, and the image side surface is convex; the sixth lens is a double concave negative lens, the object side surface of which is concave, and the image side surface is concave; wherein the fifth lens and the sixth lens form a cemented lens group; the seventh lens is a double convex positive lens, the object side surface of which is convex, and the image side surface is convex; the first lens, the third lens, the fourth lens, the fifth lens and the sixth lens are glass spherical lenses, and the second lens and the seventh lens are plastic aspherical lenses.

[0029] In this embodiment, the first lens and the second lens have negative focal power lenses, which can adjust the large-angle light, and the plastic aspherical surface in them also has the effect of reducing the distortion of the optical system. The fifth lens and the sixth lens form an achromatic double cemented lens. Reasonable lens matching makes the optical system realize low cost, 8M, super wide angle, large aperture, day and night focus, low temperature drift design, and at the same time, the on-axis and off-axis aberrations are well corrected, and the imaging quality is good.

[0030] In the embodiment, the air gap between the first lens and the second lens is 2.5-3.0 mm; the air gap between the second lens and the third lens is 0.5-1.0 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 a cemented lens 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.

[0031] In the embodiment, the aspherical surface curve equation expression of the second lens and the seventh lens is:

[0032]

[0033] wherein Z is the sagittal height of the aspherical surface at a position with a height of r along the optical axis from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface; and k is the conic constant. are high-order coefficients.

[0034] In the embodiment, the focal length of the optical system is , 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 , respectively. satisfy the following ratios: , , , , , , .

[0035] In the embodiment, the first lens satisfies the relationship: , ; the second lens satisfies the relationship: , ; the third lens satisfies the relationship: , ; the fourth lens satisfies the relationship: , ; the fifth lens satisfies the relationship: , ; the sixth lens satisfies the relationship: , ; and the seventh lens satisfies the relationship: , ; wherein is the refractive index, is the Abbe number.

[0036] ​In the embodiment, a total optical length TTL of the optical system and a focal length f of the optical system satisfy TTL / f <= 10.0; an image height H of the optical system and the focal length f of the optical system satisfy H / f >= 1.0.

[0037] In the embodiment, a filter is arranged on the right side of the seventh lens, specifically, the first equivalent glass flat plate L8 and the second equivalent glass flat plate L9 are arranged in sequence from left to right between the right side of the seventh lens and the imaging surface.

[0038] Technical indexes realized by the optical system in the embodiment are as follows:

[0039] (1) focal length: 1.0 <= EFFL <= 2.0 mm;

[0040] (2) aperture: F <= 1.6;

[0041] (3) field of view: 2w >= 194 degrees;

[0042] (4) working waveband: visible light waveband.

[0043] In the embodiment, in order to realize the design parameters, specific designs of the lenses are shown in the following table:

[0044] .

[0045] In the embodiment, aspheric coefficients of the aspheric lenses of the optical system are shown in the following table:

[0046] .

[0047] An imaging method of a low-cost 8M front-view main camera, light rays are sequentially arranged from left to right along the incident direction through the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens, and then are imaged on the imaging surface.

[0048] The optical system reasonably allocates the optical power, the surface type, the central thickness of each lens and the axial distance between each lens, etc., so as to meet the low-cost 8M super wide-angle 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.

[0049] The above only describes the preferred embodiments of the present application, and for those skilled in the art, according to the teaching of the present application, it does not need creative labor to design different forms of a low-cost 8M front-view main camera and an imaging method, and any equivalent changes, modifications, replacements and variations made within the scope of the present application should be included in the scope of the present application.

Claims

1. A low cost 8M front-facing primary camera, characterized in that, The optical system of the camera is composed of 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 the light path of the incident light; without considering the reverse bending caused by the aspherical coefficient, the first lens is a meniscus concave negative lens, the object side surface of which is convex, and the image side surface of which is concave; the second lens is a double-concave negative lens, the object side surface of which is concave, and the image side surface of which is concave; the third lens is a double-convex positive lens, the object side surface of which is convex, and the image side surface of which is convex; the fourth lens is a double-convex positive lens, the object side surface of which is convex, and the image side surface of which is convex; the fifth lens is a double-convex positive lens, the object side surface of which is convex, and the image side surface of which is convex; the sixth lens is a double-concave negative lens, the object side surface of which is concave, and the image side surface of which is concave; the seventh lens is a double-convex positive lens, the object side surface of which is convex, and the image side surface of which is convex; the first lens, the third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses, and the second lens and the seventh lens are aspherical lenses, wherein the fifth lens and the sixth lens are tightly formed into a cemented lens group; the air gap between the first lens and the second lens is 2.5-3.0 mm; the air gap between the second lens and the third lens is 0.5-1.0 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 tightly formed into a cemented lens group, and the air gap is 0 mm; the air gap between the sixth lens and the seventh lens is 0.5-1.0 mm; the focal length of the optical system is , 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 respectively , wherein and satisfy the following ratios: , , , , , , . The total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤10.

0.

2. The low-cost 8M front-facing primary camera of claim 1, wherein, The first lens, the third lens, the fourth lens, the fifth lens and the sixth lens are glass spherical lenses, and the second lens and the seventh lens are plastic aspherical lenses.

3. A low-cost 8M front-facing primary camera according to claim 1 or 2, characterized in that, The first lens satisfies the relationship: , ; the second lens satisfies the relationship: , ; the third lens satisfies the relationship: , ; the fourth lens satisfies the relationship: , ; the fifth lens satisfies the relationship: , ; the sixth lens satisfies the relationship: , ; the seventh lens satisfies the relationship: , ; wherein is a refractive index, is an Abbe number.

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

6.

5. The low-cost 8M 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.

6. A low-cost 8M front-facing primary camera according to claim 1, wherein, The right side of the seventh lens is provided with a filter.

7. An imaging method applied to the low-cost 8M front-view primary camera of claim 1, 2, 4, 5 or 6, characterized in that, Light rays are sequentially arranged from left to right along the incident direction through the first lens, the second lens, the third lens, the diaphragm, the fourth lens, the fifth lens, the sixth lens and the seventh lens, and then imaged on an imaging surface.

Images