CN111352222A

CN111352222A - Small high-definition vehicle-mounted wide-angle imaging system

Info

Publication number: CN111352222A
Application number: CN202010446087.0A
Authority: CN
Inventors: 毛磊; 张丽芝; 陈金珠; 牛晓芳; 孙秀云; 邱强; 丁晓球; 潘跃兵
Original assignee: NINGBO YONGXIN OPTICS CO Ltd
Current assignee: NINGBO YONGXIN OPTICS CO Ltd
Priority date: 2020-05-25
Filing date: 2020-05-25
Publication date: 2020-06-30
Anticipated expiration: 2040-05-25
Also published as: CN111352222B

Abstract

The invention discloses a high-definition small-sized vehicle-mounted wide-angle imaging system, which comprises a first lens group with negative focal power, a second lens group with positive focal power and a diaphragm arranged between the first lens group and the second lens group from an object side to an image side, and is characterized in that the first lens group consists of a first lens, a second lens and a third lens from the object side to the image side in sequence, the second lens group consists of a fourth lens, a fifth lens and a sixth lens from the object side to the image side in sequence, the fourth lens and the fifth lens are glued to form a cemented lens, the sixth lens is a meniscus lens with a concave object side and a convex image side, and the high-definition small-sized vehicle-mounted wide-angle imaging system has the advantages that the mixed design of six spherical surfaces and aspherical surfaces is adopted, the reasonable focal power and surface type are, through reasonable parameter matching, the beneficial effects of high pixel, low cost and miniaturization of the lens are realized, the design of an optical system enables imaging to keep stable imaging performance at-40-85 ℃.

Description

Small high-definition vehicle-mounted wide-angle imaging system

Technical Field

The invention relates to a wide-angle imaging system, in particular to a high-definition small-sized vehicle-mounted wide-angle imaging system.

Background

The wide-angle lens is widely applied to vehicle-mounted shooting equipment and security monitoring equipment, particularly, an automobile becomes a necessary transportation tool for family households at present, and the vehicle-mounted lens also becomes one of indispensable elements on the automobile. The existing wide-angle lens can meet the basic requirements of vehicle-mounted monitoring, but has many defects, such as large distortion, small angle of view, high and small image, large volume and the like. The chinese patent application publication No. CN110412730A discloses a wide-angle lens, which comprises, in order from an object side to an image side along an optical axis: the lens system comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. The first lens can have negative focal power, the object-side surface of the first lens is a convex surface, the image-side surface of the first lens is a concave surface, the second lens can have negative focal power, the object-side surface and the image-side surface of the second lens can be concave surfaces, the third lens can have positive focal power, the object-side surface and the image-side surface of the third lens are convex surfaces, the fourth lens, the fifth lens and the sixth lens are combined into a three-cemented lens, the focal length f =3.447mm, the total optical length TTL =19.611mm, the field angle FOV =192 degrees, and the image plane size phi 3.958mm can be achieved. The defects are large volume, small image height and small matching chip (1/4 million pixels).

Disclosure of Invention

The invention aims to solve the technical problem of providing a high-definition small-sized vehicle-mounted wide-angle imaging system which is small in size and can be matched with a large chip (1/2.5 three million pixels).

The technical scheme adopted by the invention for solving the technical problems is as follows: the utility model provides a small-size on-vehicle wide angle imaging system of high definition, from the object side to image side include have negative power first lens group, have positive power second lens group and set up and be in first lens group with the diaphragm between the second lens group, first lens group from the object side to image side constitute by first lens, second lens and third lens in proper order, the second lens group from the object side to image side constitute by fourth lens, fifth lens and sixth lens in proper order, the fourth lens with fifth lens veneer constitute cemented lens, sixth lens be the object side and be the meniscus lens that image side is the convex surface.

The fourth lens and the fifth lens are aspheric lenses, and the cemented lens meets the condition that 1 < | R |/(D/2) < 2, wherein R is the central curvature radius of the cemented surface, and D is the effective clear aperture of the cemented surface. The design has the advantages of facilitating the process exhaust during gluing and improving the gluing yield.

The first lens is a meniscus lens with negative focal power, the object side surface is a convex surface, the second lens is a concave lens with negative focal power, the image side surface is a concave surface, the third lens is a double convex lens with positive focal power, the fourth lens is a double convex lens with positive focal power, the fifth lens is a meniscus lens with negative focal power, the object side surface is a concave surface, the sixth lens is a meniscus lens with positive focal power, the object side surface is a concave surface, and the image side surface is a convex surface.

The focal length f of the whole imaging system satisfies: f is more than or equal to 0.8mm and less than or equal to 1.6 mm; the total optical length TTL satisfies: 11mm < TTL < 16mm and satisfies the relation 1 < TTL/phi | < 4, phi being image height.

The first lens has an abbe number Vd1, the second lens has an abbe number Vd2, the third lens has an abbe number Vd3, the fourth lens has an abbe number Vd4, the fifth lens has an abbe number Vd5, the sixth lens has an abbe number Vd6, and the lens abbe numbers satisfy the following formula: 50 < Vd1, Vd2, Vd4 and Vd6 < 80; 20 < Vd3, Vd5 < 30.

And an optical filter is arranged on the image side of the second lens group.

And chip protection glass is arranged on the image side of the optical filter.

Compared with the prior art, the invention has the advantages that through the mixed design of six spherical surfaces and aspherical surfaces, reasonable focal power and surface type are matched, and through reasonable parameter matching, the beneficial effects of high pixel, low cost and miniaturization of the lens are realized, so that the imaging performance of the optical system can be stably kept at minus 40-85 ℃. The size of the image plane of the invention can reach phi 6mm, and the invention can match with a large chip (1/2.5 three million pixels), and simultaneously the total length is reduced (TTL =14.83 mm), so that the lens is miniaturized.

Drawings

FIG. 1 is a schematic diagram of an optical configuration of an embodiment of the present invention;

FIG. 2 is a graph of a 20 ℃ transfer function of an embodiment of the present invention;

FIG. 3 is a field curvature diagram of an embodiment of the present invention;

FIG. 4 is a distortion diagram of an embodiment of the present invention;

fig. 5 is a relative illuminance diagram of an embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are for reference and illustration only and are not to be construed as limiting the scope of the invention.

Example (b):

a high-definition small-sized vehicle-mounted wide-angle imaging system, as shown in FIG. 1, includes, from an object side to an image side, a first lens group L11 having negative power, a second lens group L12 having positive power, and a stop G disposed between the first lens group L11 and the second lens group L12, the image side of the second lens group is provided with a filter IR, the image side of the filter is provided with a chip protection glass CG, the first lens group L11 is composed of, in order from the object side to the image side, a first lens L1, a second lens L2, and a third lens L3, the first lens L1 is a meniscus lens having negative power and a convex object side, the second lens L2 is a concave lens having negative power and a concave image side, the third lens L3 is a double-convex lens having positive power, the second lens group L12 is composed of, in order from the object side to the image side, a fourth lens L4, a fifth lens L5, and a sixth lens L6, the fourth lens L4 is a double-convex lens having positive power, the fifth lens element L5 is a meniscus lens element with negative power and a concave object-side surface, and the sixth lens element is a meniscus lens element with positive power and a concave object-side surface and a convex image-side surface.

The abbe number of the first lens L1 is Vd1, the abbe number of the second lens L2 is Vd2, the abbe number of the third lens L3 is Vd3, the abbe number of the fourth lens L4 is Vd4, the abbe number of the fifth lens L5 is Vd5, the abbe number of the sixth lens L6 is Vd6, and the lens abbe numbers satisfy the following conditions: 50 < Vd1, Vd2, Vd4 and Vd6 < 80; 20 < Vd3, Vd5 < 30.

The fourth lens L4 and the fifth lens L5 are cemented to form a cemented lens, the fourth lens L4 and the fifth lens L5 are aspheric lenses, and the cemented lens satisfies 1 < | R |/(D/2) < 2, wherein R is the central curvature radius of the cemented surface, and D is the effective clear aperture of the cemented surface.

In this embodiment, the first lens L1 and the third lens L3 are spherical lenses, the second lens L2, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are aspheric lenses, and the aspheric surface type satisfies the following equation:

y represents a radial coordinate value of the lens perpendicular to the optical axis, Z is a distance vector from the aspheric vertex when the aspheric lens is at a position having a height y in the optical axis direction, c =1/R, R represents a central curvature radius of the corresponding aspheric lens profile, k represents a conic coefficient, and the parameter A, B, C, D, E is a high-order term coefficient.

The main design parameters of this example are shown in the following table:

in this embodiment, the physical optical parameters of the whole lens are expressed as follows:

the aspheric lens high order coefficients in this embodiment are as follows:

the embodiment of the invention adopts a six-piece structure, realizes a short focal length of 1.46mm, a maximum field angle of 200 degrees, an optical total length of 14.83mm and a full image height of 6mm, and realizes miniaturization, high pixel and low cost of an optical lens.

Fig. 2 is a graph of the 20 ℃ transfer function of the present embodiment, in which the ordinate represents the MTF (spatial resolution) value and the abscissa represents the spatial frequency, and it can be seen that the MTF value decreases with increasing spatial frequency for each field.

FIG. 3 is a field curvature diagram of the present embodiment, in which the ordinate represents the field angle and the abscissa represents the range, and it can be seen from the diagram that the field curvature changes corresponding to the field angle of each wavelength between-1 mm and 1 mm;

FIG. 4 is a distortion diagram of the present embodiment, in which the ordinate represents the angle of view and the abscissa represents the range, and it can be seen from the diagram that the distortion of the angle of view for each wavelength varies between-100% and 100%;

fig. 5 is a relative illuminance diagram of the present example, in which the ordinate represents relative illuminance and the abscissa represents angle of view, and it can be seen that the relative illuminance decreases as the angle of view increases.

The above description is only an example of the present invention, and should not be construed as limiting the scope of the present invention, therefore, the appended claims should not be construed as limited to the above description.

Claims

1. A high-definition small-sized vehicle-mounted wide-angle imaging system comprises a first lens group with negative focal power, a second lens group with positive focal power and a diaphragm arranged between the first lens group and the second lens group from an object side to an image side, and is characterized in that: the first lens group consists of a first lens, a second lens and a third lens from the object side to the image side in sequence, the second lens group consists of a fourth lens, a fifth lens and a sixth lens from the object side to the image side in sequence, the fourth lens and the fifth lens are glued to form a cemented lens, and the sixth lens is a meniscus lens with a concave object side and a convex image side.

2. The small vehicle-mounted wide-angle imaging system of high definition of claim 1, characterized in that: the fourth lens and the fifth lens are aspheric lenses, and the cemented lens meets the condition that 1 < | R |/(D/2) < 2, wherein R is the central curvature radius of the cemented surface, and D is the effective clear aperture of the cemented surface.

3. The small vehicle-mounted wide-angle imaging system of high definition of claim 1, characterized in that: the first lens is a meniscus lens with negative focal power, the object side surface is a convex surface, the second lens is a concave lens with negative focal power, the image side surface is a concave surface, the third lens is a double convex lens with positive focal power, the fourth lens is a double convex lens with positive focal power, the fifth lens is a meniscus lens with negative focal power, the object side surface is a concave surface, the sixth lens is a meniscus lens with positive focal power, the object side surface is a concave surface, and the image side surface is a convex surface.

4. The small vehicle-mounted wide-angle imaging system of high definition of claim 1, characterized in that: the focal length f of the whole imaging system satisfies: f is more than or equal to 0.8mm and less than or equal to 1.6 mm; the total optical length TTL satisfies: 11mm < TTL < 16mm and satisfies the relation 1 < TTL/phi | < 4, phi being image height.

5. The small vehicle-mounted wide-angle imaging system of high definition of claim 1, characterized in that: the first lens has an abbe number Vd1, the second lens has an abbe number Vd2, the third lens has an abbe number Vd3, the fourth lens has an abbe number Vd4, the fifth lens has an abbe number Vd5, the sixth lens has an abbe number Vd6, and the lens abbe numbers satisfy the following formula: 50 < Vd1, Vd2, Vd4 and Vd6 < 80; 20 < Vd3, Vd5 < 30.

6. The small vehicle-mounted wide-angle imaging system of high definition of claim 1, characterized in that: and an optical filter is arranged on the image side of the second lens group.

7. The small vehicle-mounted wide-angle imaging system of high definition of claim 6, wherein: and chip protection glass is arranged on the image side of the optical filter.