CN110673302A

CN110673302A - Super wide-angle lens

Info

Publication number: CN110673302A
Application number: CN201910830861.5A
Authority: CN
Inventors: 范智宇; 张世忠; 张荣曜; 戴敏林
Original assignee: Fujian Forecam Optics Co Ltd
Current assignee: Fujian Forecam Optics Co Ltd
Priority date: 2019-09-04
Filing date: 2019-09-04
Publication date: 2020-01-10
Anticipated expiration: 2039-09-04
Also published as: CN110673302B

Abstract

The invention relates to an ultra-wide angle lens, which comprises a meniscus negative lens A1, a meniscus lens A2, a meniscus negative lens A3, a biconvex positive lens B1, a biconvex positive lens B2 and a meniscus negative lens B3 which are sequentially arranged along the incident direction of light rays from left to right, a gluing piece formed by tightly connecting the biconvex positive lens B2 and the meniscus negative lens B3, the image side of the meniscus negative lens B3 is provided with parallel flat glass, the parallel flat glass is positioned in front of an IMA image surface, the air interval between the meniscus negative lens A1 and the meniscus negative lens A2 is 1.61mm-1.63mm, the air interval between the meniscus negative lens A2 and the meniscus negative lens A3 is 2.54mm-2.56mm, the air interval between the meniscus negative lens A3 and the biconvex positive lens B1 is 0.60mm-0.61mm, the air interval between the biconvex positive lens B1 and the biconvex positive lens B351.37 mm, and the simple field angle structure is a small field angle structure with a simple angle of 170 mm, and a simple structure, Low distortion, day and night confocal and high resolution.

Description

Super wide-angle lens

Technical Field

The invention relates to an ultra-wide angle lens.

Background

In recent years, as the application range of the imaging lens is wider, the requirements on the pixel and the field angle of the lens are higher and higher. However, the existing lens generally has the following disadvantages: the field angle is not large enough and is often less than 140 degrees, and one or even a plurality of lenses are required to be arranged to shoot the required range; the imaging at night is not satisfied, or the imaging at night is not confocal, and the refocusing is needed during the imaging at night; distortion under a large view field is large, the overall dimension is large, and the occupied space is large.

Disclosure of Invention

In view of the shortcomings of the prior art, the technical problem to be solved by the invention is to provide an ultra-wide angle lens.

In order to solve the technical problems, the technical scheme of the invention is as follows: an ultra-wide-angle lens comprises a meniscus negative lens A1, a meniscus lens A2, a meniscus negative lens A3, a biconvex positive lens B1, a biconvex positive lens B2 and a meniscus negative lens B3 which are sequentially arranged along the incident direction of light rays from left to right, a gluing piece formed by the biconvex positive lens B2 and the meniscus negative lens B3 in a sealing mode, and a parallel flat plate is arranged on the image side of the meniscus negative lens B3 and positioned in front of an IMA image surface.

Further, the air space between the negative meniscus lens a1 and the negative meniscus lens a2 is 1.61mm to 1.63mm, the air space between the negative meniscus lens a2 and the negative meniscus lens A3 is 2.54mm to 2.56mm, the air space between the negative meniscus lens A3 and the double-convex positive lens B1 is 0.60mm to 0.61mm, and the air space between the double-convex positive lens B1 and the adhesive is 1.37mm to 1.38 mm.

Further, the focal length of the lens is set to be f, the focal lengths of the lenses in the incident direction are respectively f1, f2, f3, f4, f5 and f6, and the focal lengths meet the requirements of-3.2 < f1/f < -2.3, -3.2< f2/f < -2.3, 9< f3/f <10, -2.2< f4/f < -1.5, 2< f5/f <3 and 3< f6/f < 3.6.

Further, the diaphragm of the lens is a convex surface of a rear group of biconvex positive lens B1 on the object side.

Compared with the prior art, the invention has the following beneficial effects: the lens has simple structure, small volume, 170-degree field angle, low distortion, day and night confocal and high resolution, can shoot a scene in a larger range, and can be matched with a CCD or CMOS chip with 500 ten thousand pixels for use.

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

Drawings

FIG. 1 is a schematic diagram of an optical system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a visible light MTF value according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of an infrared MTF value at 850nm according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a defocusing of a visible light MTF according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a 850nm infrared MTF defocus in accordance with an embodiment of the present invention;

FIG. 6 is a schematic view of field curvature and F-Theta distortion according to an embodiment of the present invention.

In the figure: 1-meniscus negative lens a1, 2-meniscus lens a2, 3-meniscus negative lens A3, 4-biconvex positive lens B1, 5-biconvex positive lens B2; 6-meniscus negative lens B3; 7-parallel plates; 8-IMA image plane.

Detailed Description

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

As shown in fig. 1-6, an ultra-wide angle lens includes a negative meniscus lens a1, a meniscus lens a2, a negative meniscus lens A3, a double convex positive lens B1, a double convex positive lens B2, and a negative meniscus lens B3, which are sequentially disposed along a left-to-right incident direction of light, wherein the double convex positive lens B2 and the negative meniscus lens B3 are tightly bonded to form a cemented part, and a parallel flat glass is disposed on an image side of the negative meniscus lens B3 and is located in front of an IMA image plane.

In this embodiment, the air space between the negative meniscus lens a1 and the negative meniscus lens a2 is 1.61mm to 1.63mm, the air space between the negative meniscus lens a2 and the negative meniscus lens A3 is 2.54mm to 2.56mm, the air space between the negative meniscus lens A3 and the double-convex positive lens B1 is 0.60mm to 0.61mm, and the air space between the double-convex positive lens B1 and the adhesive is 1.37mm to 1.38 mm.

In the embodiment, the focal length of the lens is set to be f, the focal lengths of the lenses in the incident direction are respectively f1, f2, f3, f4, f5 and f6, and the focal lengths meet the requirements of-3.2 < f1/f < -2.3, -3.2< f2/f < -2.3, 9< f3/f <10, -2.2< f4/f < -1.5, 2< f5/f <3 and 3< f6/f < 3.6.

In this embodiment, the stop of the lens is a convex surface of the rear group of biconvex positive lens B1 on the object side.

In this embodiment, the optical structure formed by the above lens assembly achieves the following optical indexes: focal length: EFFL =2.35 mm; f number = 2.35; the field angle: 2w is more than or equal to 170 degrees; the diameter of the imaging circle is more than phi 6.6; working spectral range: 430 nm-850 nm; the total optical length TTL is less than or equal to 20mm, and the optical rear intercept is more than or equal to 4.7 mm; ) The chief ray incidence angle CRA is less than or equal to 12.8 degrees; F-Theta distortion = -5.3%; the lens is suitable for 500 ten thousand pixel high-resolution CCD or CMOS cameras.

When the lens is designed, longer wavelength is added into a considered range, a broad spectrum of 435 nm-850 nm is adopted, the visible light and the infrared light realize confocal, and meanwhile, a night vision scene can be applied. By reasonably distributing the focal power of 6 lenses, the total optical length of the lens is compressed while small distortion is kept, so that the optical system has a compact structure and is beneficial to saving the use cost.

The lens adopts a six-piece structure, the focal power is reasonably distributed, the front three pieces of lenses converge the incident angle of light, and the back three pieces of lenses carry out aberration balance. The double-convex positive lens B2 with the spherical surface of the glass adopts the glass with low refractive index and high Abbe number, and the negative meniscus lens B3 with the spherical surface of the glass adopts the glass with high refractive index and low Abbe number, so that the secondary spectrum and spherical aberration are well corrected, and the lens system is well corrected through reasonable collocation of glass materials and chromatic aberration.

The specific parameters of each lens are as follows:

the above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.

Claims

1. An ultra-wide angle lens, characterized in that: the imaging lens comprises a negative meniscus lens A1, a meniscus lens A2, a negative meniscus lens A3, a double-convex positive lens B1, a double-convex positive lens B2 and a negative meniscus lens B3 which are sequentially arranged along the incident direction of light rays from left to right, wherein a gluing part formed by tightly connecting the double-convex positive lens B2 and the negative meniscus lens B3 is arranged on the image side of the negative meniscus lens B3, and the parallel flat plate is positioned in front of an IMA image surface.

2. The ultra-wide angle lens of claim 1, wherein: the air space between the negative meniscus lens A1 and the negative meniscus lens A2 is 1.61mm-1.63mm, the air space between the negative meniscus lens A2 and the negative meniscus lens A3 is 2.54mm-2.56mm, the air space between the negative meniscus lens A3 and the double-convex positive lens B1 is 0.60mm-0.61mm, and the air space between the double-convex positive lens B1 and the adhesive is 1.37mm-1.38 mm.

3. The ultra-wide angle lens of claim 1, wherein: the focal length of the lens is set to be f, the focal lengths of the lenses in the incident direction are respectively f1, f2, f3, f4, f5 and f6, and the focal lengths meet the requirements of-3.2 < f1/f < -2.3, -3.2< f2/f < -2.3, 9< f3/f <10, -2.2< f4/f < -1.5, 2< f5/f <3 and 3< f6/f < 3.6.

4. The ultra-wide angle lens of claim 1, wherein: the diaphragm of the lens is a convex surface of a rear group of biconvex positive lens B1 on the object side.