A low-cost 8M front-view optical system

Abstract

The utility model relates to a low-cost 8M front-view optical system, wherein the lenses with optical power along the incident light path of the optical system are the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens in sequence, an aperture is arranged between the fourth lens and the fifth lens, wherein the fifth lens and the sixth lens are closely connected to form a cemented lens group; the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus 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 first, second, fourth, fifth and sixth lenses are glass spherical lenses, and the third and seventh lenses are plastic aspherical lenses. The imaging angle of the lens to the object is greater than 194 degrees, and it has the advantages of ultra-high 8M imaging clarity, large clear aperture, low tolerance sensitivity and good high and low temperature stability.

Description

Technical Field

[0001] The utility model relates to the technical field of lenses, in particular to a low-cost 8M front-view optical system. Background Art

[0002] Since the beginning of the 21st century, people's demand for cars is no longer just satisfied with more powerful power, more comfortable driving experience and more reliable safety. With the development of electronics, artificial intelligence, 5G and other technologies as well as industrial design and manufacturing capabilities, intelligence has become a definite trend in the development of today's automotive industry, especially smart car technologies represented by autonomous driving, ADAS, smart cockpits, etc. have become the technological high ground that major technology companies are vying to seize.

[0003] The front camera installed on the front windshield is mainly used to realize the visual perception and recognition function of driving. According to the function, it can be divided into the front main camera, the front narrow-angle camera and the front wide-angle camera. However, the use of three cameras greatly increases the cost of the entire camera module, which is not conducive to market popularization. For this reason, an ultra-wide-angle 8MP lens is used to realize a single-lens front camera module. However, in order to take into account its ultra-wide angle, high image quality, large aperture, low temperature drift and other optical properties, it is often necessary to use multiple glass pieces, which increases the cost. Utility Model Content

[0004] In view of this, the purpose of the utility model is to provide a low-cost 8M front-view optical system with a large imaging angle, which meets the low-cost 8M ultra-wide-angle imaging performance requirements of the lens and has a smaller outer size.

[0005] The utility model adopts the following scheme to achieve: a low-cost 8M front-view optical system, wherein the lenses with optical focal length along the incident light path of the optical system are sequentially a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, an aperture is arranged between the fourth lens and the fifth lens, wherein the fifth lens and the sixth lens are closely connected to form a cemented lens group; the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus 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 first, second, fourth, fifth and sixth lenses are glass spherical lenses, and the third and seventh lenses are plastic aspherical lenses.

[0006] 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, 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 ratio with f: -4.0 <f1 / f<-3.0,-3.0<f2 / f<-2.0,11.0<f3 / f<12.0,2.0<f4 / f<3.0,1.0<f5 / f<2.0,-2.0<f6 / f<-1.0,3.0<f7 / f<4.0。

[0007] Furthermore, the first lens satisfies the relationship: 2.0≤Nd≤2.3, Vd≤50.0; the second lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the third lens satisfies the relationship: 1.5≤Nd≤1.8, Vd≤50.0; the fourth lens satisfies the relationship: 2.0≤Nd≤2.3, Vd≤50.0; the fifth lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the sixth lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the seventh lens satisfies the relationship: 1.5≤Nd≤1.8, Vd≥50.0; wherein Nd is the refractive index and Vd is the Abbe constant.

[0008] Furthermore, the air gap between the first lens and the second lens is 2.0~2.5mm; the air gap between the second lens and the third lens is 1.0~1.5mm; the air gap between the third lens and the fourth lens is 1.1~1.5mm; the air gap between the fourth lens and the aperture is 0.1~0.5mm; the air gap between the aperture and the fifth lens is 0.1~0.5mm; and the air gap between the sixth lens and the seventh lens is 0.5~1.0mm.

[0009] Furthermore, a filter is arranged on the rear side of the seventh lens.

[0010] Compared with the prior art, the utility model has the following beneficial effects:

[0011] 1. The imaging angle of the lens is greater than 194 degrees. It has the advantages of ultra-high 8M imaging clarity, large aperture, low tolerance sensitivity and good high and low temperature stability. At the same time, it can monitor the scene outside the car more comprehensively.

[0012] 2. Through the reasonable matching of optical lenses, the system structure is compact and reasonable, easy to assemble, with low tolerance sensitivity, and more suitable for large-scale high-yield production;

[0013] 3. The glass-plastic hybrid structure has lower manufacturing cost and lighter weight, which is conducive to the manufacture and installation of modules;

[0014] 4. Able to make good compensation for focal plane displacement at high and low temperatures, and have adaptability to complex environments;

[0015] 5. Corrected axial chromatic aberration, vertical chromatic aberration and high-order chromatic aberration to ensure that the imaging system can have high imaging quality at a large angle

[0016] 6. Give full play to the advantages of aspherical lenses in correcting aberrations, meet the requirements of high-definition imaging, have a smaller lens outer diameter and a shorter total optical length, and ensure the miniaturization of the lens.

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below through specific embodiments and related drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the optical structure of the utility model;

[0019] Figure 2 It is the axial chromatic aberration diagram of the full working band of the utility model;

[0020] Figure 3 It is the vertical axis chromatic aberration diagram of the full working band of the utility model;

[0021] Figure 4 It is the field curvature distortion diagram of the full working band of the utility model;

[0022] Explanation of the numbers in the figure: STO-aperture; L1-first lens; L2-second lens; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-seventh lens; L8-equivalent glass plate; L9-equivalent glass plate; IMA-imaging surface. DETAILED DESCRIPTION

[0023] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] like Figures 1 to 4As shown, a low-cost 8M front-view optical system, wherein the lenses having optical power along the incident light path of the optical system are sequentially a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, an aperture is arranged between the fourth lens and the fifth lens, wherein the fifth lens and the sixth lens are closely connected to form a cemented lens group; without considering the backcurvature caused by the aspheric coefficient, 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 meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; The third lens is a meniscus convex positive lens, whose object side surface is convex and whose image side surface is concave; the fourth lens is a double convex positive lens, whose object side surface is convex and whose image side surface is convex; the fifth lens is a double convex positive lens, whose object side surface is convex and whose image side surface is convex; the sixth lens is a double concave negative lens, whose object side surface is concave and whose image side surface is concave; the seventh lens is a double convex positive lens, whose object side surface is convex and whose image side surface is convex; the lenses are made of plastic and glass materials, among which the first, second, fourth, fifth and sixth lenses are glass spherical lenses, and the third and seventh lenses are plastic aspherical lenses.

[0026] Reasonable lens matching enables the optical system to achieve low cost, 8M, ultra-wide angle, large aperture, day and night confocal, low temperature drift design, and at the same time, the on-axis and off-axis aberrations are well corrected, with good imaging quality, such as Figures 2 to 4 shown.

[0027] 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, 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 ratio with f: -4.0 <f1 / f<-3.0,-3.0<f2 / f<-2.0,11.0<f3 / f<12.0,2.0<f4 / f<3.0,1.0<f5 / f<2.0,-2.0<f6 / f<-1.0,3.0<f7 / f<4.0。

[0028] In this embodiment, the first lens satisfies the relationship: 2.0≤Nd≤2.3, Vd≤50.0; the second lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the third lens satisfies the relationship: 1.5≤Nd≤1.8, Vd≤50.0; the fourth lens satisfies the relationship: 2.0≤Nd≤2.3, Vd≤50.0; the fifth lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the sixth lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the seventh lens satisfies the relationship: 1.5≤Nd≤1.8, Vd≥50.0; wherein Nd is the refractive index and Vd is the Abbe constant.

[0029] In this embodiment, the axial distances between the lenses satisfy the following relationship: the air gap between the first lens and the second lens is 2.0~2.5mm; the air gap between the second lens and the third lens is 1.0~1.5mm; the air gap between the third lens and the fourth lens is 1.1~1.5mm; the air gap between the fourth lens and the aperture is 0.1~0.5mm; the air gap between the aperture and the fifth lens is 0.1~0.5mm; and the air gap between the sixth lens and the seventh lens is 0.5~1.0mm.

[0030] In this embodiment, the third and seventh lenses are both aspherical lenses, and the aspherical curve equation is expressed as:

[0031] ,

[0032] Wherein, Z is the height of the aspheric surface from the vertex of the aspheric surface when the aspheric surface is at a height of r along the optical axis; c is the paraxial curvature of the aspheric surface; k is the cone constant; , , , , , , , All are high-order coefficients.

[0033] The aspheric coefficients of each aspheric lens are as follows:

[0034]

[0035] In this embodiment, the total optical length TTL of the optical system and the focal length f of the optical system satisfy the following relationship: TTL / f≤10.0.

[0036] In this embodiment, the F number of the optical system is ≤1.6.

[0037] In this embodiment, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≥1.0.

[0038] In this embodiment, a filter is disposed on the rear side of the seventh lens.

[0039] The technical indicators achieved by the optical system of this embodiment are as follows:

[0040] (1) Focal length: 1.0 ≤ EFFL ≤ 2.0 mm;

[0041] (2) Aperture F ≤ 1.6;

[0042] (3) Field of view: 2w ≥ 194°;

[0043] (4) Working band: visible light band.

[0044] To achieve the above design parameters, the specific parameters of the optical system of this embodiment are shown in the following table:

[0045]

[0046] The optical system of this embodiment reduces the total length of the lens and the radial size of each lens by reasonably allocating the optical power, surface shape, center thickness of each lens, and axial distance between each lens, while meeting the low-cost 8M ultra-wide-angle imaging performance requirements of the lens, thereby miniaturizing the lens group.

[0047] Unless otherwise stated, any technical solution disclosed in the above utility model, if it discloses a numerical range, then the disclosed numerical range is a preferred numerical range. Any technician in the field should understand that the preferred numerical range is only a numerical value with a more obvious technical effect or representative value among many feasible numerical values. Since there are too many numerical values ​​to be exhaustive, the utility model discloses only some numerical values ​​to illustrate the technical solution of the utility model, and the numerical values ​​listed above should not constitute a limitation on the scope of protection of the utility model.

[0048] If the present invention discloses or involves components or structures 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 one-piece molding using a casting process) (except when it is obviously impossible to use an one-piece molding process).

[0049] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in the above utility model include states or shapes that are approximate, similar or close thereto.

[0050] Any component provided by the utility model can be assembled from multiple separate components, or can be a separate component manufactured by an integrated molding process.

[0051] The above is only the preferred embodiment of the utility model, and does not limit the utility model in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the utility model without departing from the technical solution of the utility model still belongs to the protection scope of the technical solution of the utility model.

Claims

1. A low-cost 8M front-view optical system, characterized by: The lenses with optical power along the incident light path of the optical system are sequentially the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens, an aperture is arranged between the fourth lens and the fifth lens, wherein the fifth lens and the sixth lens are closely connected to form a cemented lens group; the first lens is a meniscus concave negative lens, the second lens is a meniscus concave negative lens, the third lens is a meniscus 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 first, second, fourth, fifth and sixth lenses are glass spherical lenses, and the third and seventh lenses are plastic aspherical lenses; 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, f7 and f satisfy the following ratio: -4.0< f1 / f<-3.0, -3.0< f2 / f<-2.0, 11.0< f3 / f<12.0, 2.0< f4 / f<3.0, 1.0< f5 / f<2.0, -2.0< f6 / f<-1.0, 3.0< f7 / f<4.0; the air gap between the first lens and the second lens is 2.0~2.5mm; the air gap between the second lens and the third lens is 1.0~1.5mm; the air gap between the third lens and the fourth lens is 1.1~1.5mm; the air gap between the fourth lens and the aperture is 0.1~0.5mm; the air gap between the aperture and the fifth lens is 0.1~0.5mm; the air gap between the sixth lens and the seventh lens is 0.5~1.0mm; the focal length of the optical system: 1.0≤EFFL≤2.0mm.

2. The low-cost 8M front-view optical system according to claim 1, characterized in that: The first lens satisfies the relationship: 2.0≤Nd≤2.3, Vd≤50.0; the second lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the third lens satisfies the relationship: 1.5≤Nd≤1.8, Vd≤50.0; the fourth lens satisfies the relationship: 2.0≤Nd≤2.3, Vd≤50.0; the fifth lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the sixth lens satisfies the relationship: 1.7≤Nd≤2.0, Vd≤50.0; the seventh lens satisfies the relationship: 1.5≤Nd≤1.8, Vd≥50.0; wherein Nd is the refractive index and Vd is the Abbe constant.

3. The low-cost 8M front-view optical system according to claim 1, characterized in that: A filter is arranged on the rear side of the seventh lens.

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