CN110737079A

CN110737079A - Super -angle lens and working method thereof

Info

Publication number: CN110737079A
Application number: CN201910989602.7A
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: 2019-10-17
Filing date: 2019-10-17
Publication date: 2020-01-31

Abstract

The invention relates to a super angle lens, which comprises a front group A, a rear group B, a parallel flat plate and an IMA image surface which are sequentially arranged along the incident direction of light rays from left to right, wherein the front group A comprises a th meniscus negative lens, a second meniscus negative lens and a third meniscus negative lens which are sequentially arranged, the rear group B comprises a th biconvex positive lens, a second biconvex positive lens and a fourth meniscus negative lens which are sequentially arranged, and the second biconvex positive lens and the fourth meniscus negative lens are tightly connected to form a gluing part.

Description

Super -angle lens and working method thereof

Technical Field

The invention relates to super -degree lenses and a working method thereof.

Background

In recent years, with the application range of the camera lens becoming more and more, people have higher requirements on the pixel and the angle of view of the lens, but the existing lens has the common defects that the angle of view is not large enough and is often smaller than 140 degrees, or even more lenses are needed to shoot the required range, night imaging is not satisfied or day and night imaging is not confocal, refocusing is needed during night imaging, distortion under a large field of view is large, the external dimension is large, and the occupied space is large.

Disclosure of Invention

In view of the defects of the prior art, the technical problem to be solved by the invention is to provide super -degree lenses and a working method thereof, the structure is simple and reasonable, the size is small, the field angle is 170 degrees, the distortion is low, the day and night are confocal, and the resolution is high.

In order to solve the technical problems, the technical scheme of the invention is that super- -degree lenses comprise a front group A, a rear group B, a parallel flat plate and an IMA image surface which are sequentially arranged along the incident direction of light rays from left to right, wherein the front group A comprises a th negative meniscus lens, a second negative meniscus lens and a third negative meniscus lens which are sequentially arranged, the rear group B comprises a th double-convex positive lens, a second double-convex positive lens and a fourth negative meniscus lens which are sequentially arranged, and the second double-convex positive lens and the fourth negative meniscus lens are tightly connected to form a gluing piece.

And , the convex surface of the double convex positive lens on the object side is a diaphragm.

And , the air space between the negative meniscus lens and the second negative meniscus lens is 1.61mm-1.63mm, the air space between the second negative meniscus lens and the third negative meniscus lens is 2.54mm-2.56mm, the air space between the third negative meniscus lens and the double convex positive lens is 0.60mm-0.61mm, and the air space between the double convex positive lens and the adhesive is 1.37mm-1.38 mm.

, setting the total focal length of the optical system as f, and setting the focal lengths of the negative meniscus lens, the second negative meniscus lens, the third negative meniscus lens, the double convex positive lens, the second double convex positive lens and the fourth negative meniscus lens as f1, f2, f3, f4, f5 and f6 in turn along the incident direction of the light ray, wherein the focal lengths of the lenses are-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.

The invention provides another technical schemes, which are characterized in that a working method of ultra- -degree lenses comprises the ultra- -degree lenses, wherein when light rays enter a front group A, a rear group B and a parallel flat plate in sequence, imaging is finally carried out on an IMA image surface, when the light rays pass through the front group A, three lenses of the front group A can converge the incident angle of the light rays, when the light rays pass through the rear group B, three lenses of the rear group B can carry out aberration balance, a second biconvex positive lens of a glass spherical surface in a gluing group adopts glass with low refractive index and high Abbe number, a fourth meniscus negative lens of the glass spherical surface in the gluing group adopts glass with high refractive index and low Abbe number, and when the light rays pass through the gluing group, secondary spectrum and spherical aberration can be corrected, so that a lens system can be reasonably corrected through glass materials, and chromatic aberration matching is well corrected.

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 invention is described in further detail with reference to the figures and the detailed description.

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 for an embodiment of the present invention;

in the figure, 100-front group A, 110- th meniscus negative lens, 120-second meniscus negative lens, 130-third meniscus negative lens, 200-rear group B, 210- th double convex positive lens, 220-second double convex positive lens, 230-fourth meniscus negative lens, 300-parallel flat plate and 400-IMA image surface.

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 to 6, super angle lenses include a front group a100, a rear group B200, a parallel flat plate 300, and an IMA image plane 400 sequentially arranged along a left-right incident direction of light, where the front group a100 includes a th negative meniscus lens 110, a second negative meniscus lens 120, and a third negative meniscus lens 130 sequentially arranged, the rear group B200 includes a th double convex positive lens 210, a second double convex positive lens 220, and a fourth negative meniscus lens 230 sequentially arranged, and the second double convex positive lens 220 and the fourth negative meniscus lens 230 are tightly connected to form a cemented piece.

Further , the object-side convex surface of the th biconvex positive lens 210 is a stop.

Further , the air space between the negative meniscus lens 110 and the second negative meniscus lens 120 is 1.61mm to 1.63mm, the air space between the second negative meniscus lens 120 and the third negative meniscus lens 130 is 2.54mm to 2.56mm, the air space between the third negative meniscus lens 130 and the double convex positive lens 210 is 0.60mm to 0.61mm, and the air space between the double convex positive lens 210 and the glue is 1.37mm to 1.38 mm.

, the total focal length of the optical system is set to f, and the focal lengths of the negative meniscus lens 110, the second negative meniscus lens 120, the third negative meniscus lens 130, the double convex positive lens 210, the second double convex positive lens 220, and the fourth negative meniscus lens 230 are sequentially set to f1, f2, f3, f4, f5, and f6 in the light incident direction, and the focal lengths of the respective lenses are as follows, i.e., -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.

TABLE 1 specific lens parameters are as follows

In this embodiment, the technical indexes of the optical system are as follows: (1) focal length: EFFL =2.35 mm; (2) f number = 2.35; (3) the field angle: 2w is more than or equal to 170 degrees; (4) the diameter of the imaging circle is more than phi 6.6; (5) working spectral range: 430 nm-850 nm; (6) 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; (7) the chief ray incidence angle CRA is less than or equal to 12.8 degrees; (8) F-Theta distortion = -5.3%; (9) the lens is suitable for 500 ten thousand pixel high-resolution CCD or CMOS cameras.

working methods of the hyper angle lens include the hyper angle lens, when light enters, the light path enters the front group A100, the rear group B200, the parallel flat plate 300 in sequence, imaging is finally carried out on the IMA image plane 400, when the light passes through the front group A100, the three lenses of the front group A100 can converge the incident angle of the light, when the light passes through the rear group B200, the three lenses of the rear group B200 can carry out aberration balance, the second biconvex positive lens 220 of the glass spherical surface in the cemented group adopts glass with low refractive index and high Abbe number, the fourth meniscus negative lens 230 of the glass spherical surface in the cemented group adopts glass with high refractive index and low Abbe number, when the light passes through the cemented group, the secondary spectrum and spherical aberration can be corrected, so that the lens system can obtain good correction through reasonable collocation of glass materials and chromatic aberration.

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 second biconvex positive lens 220 of the glass spherical surface is made of glass with low refractive index and high abbe number, and the fourth meniscus negative lens 230 of the glass spherical surface is made of 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.

As can be seen from fig. 2 and 3, the MTF of the central field of view of the lens in the visible light band and the infrared light band of 850nm is greater than 0.6, the MTF of the edge field of view is greater than 0.35, the imaging quality is good, and the lens is suitable for a 500-ten-thousand-pixel high-resolution CCD or CMOS camera; as can be seen from the figures 4 and 5, the defocusing amount of the central view field of the lens at the visible light wave band and the infrared light wave band of 850nm is less than 4 μm, and the day and night confocal property is met; as can be seen from FIG. 6, the field curvature of the lens is small, and the F-Theta distortion is = -5.3%, and the distortion is small.

The above-mentioned operation flow and software and hardware configuration are only used as the preferred embodiment of the present invention, and not to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or directly or indirectly applied to the related art, are included in the scope of the present invention.

Claims

The super- -angle lens is characterized by comprising a front group A, a rear group B, a parallel flat plate and an IMA image surface which are sequentially arranged along the incident direction of light rays from left to right, wherein the front group A comprises a negative meniscus lens, a second negative meniscus lens and a third negative meniscus lens which are sequentially arranged, the rear group B comprises a double-convex positive lens, a second double-convex positive lens and a fourth negative meniscus lens which are sequentially arranged, and the second double-convex positive lens and the fourth negative meniscus lens are tightly connected to form a gluing part.
2. The super angle lens of claim 1, wherein the object-side convex surface of the th biconvex positive lens is a stop.
3. The super angle lens of claim 2, wherein the air space between the negative meniscus lens and the second negative meniscus lens is 1.61mm to 1.63mm, the air space between the second negative meniscus lens and the third negative meniscus lens is 2.54mm to 2.56mm, the air space between the third negative meniscus lens and the double convex positive lens is 0.60mm to 0.61mm, and the air space between the double convex positive lens and the glue is 1.37mm to 1.38 mm.
4. The super angle lens of claim 3, wherein the total focal length of the optical system is set to f, the focal lengths of the lenses of the negative meniscus lens, the second negative meniscus lens, the third negative meniscus lens, the double convex positive lens, the second double convex positive lens and the fourth negative meniscus lens are sequentially set to f1, f2, f3, f4, f5 and f6 along the incident direction of the light, and the focal lengths of the lenses are-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.
The working method of 5, super angle lens, including the super angle lens as stated in claim 4, characterized in that, when the light enters, the light path enters into the front group A, the back group B, the parallel flat plate in sequence, finally the image is formed on the IMA image surface, when the light passes through the front group A, the three lenses of the front group A can converge the incident angle of the light, when the light passes through the back group B, the three lenses of the back group B can carry out aberration balance, the second biconvex positive lens of the glass sphere in the cemented group adopts the glass with low refractive index and high Abbe number, the fourth meniscus negative lens of the glass sphere in the cemented group adopts the glass with high refractive index and low Abbe number, when the light passes through the cemented group, the second level spectrum and spherical aberration can be corrected, so that the lens system can obtain good correction through the reasonable collocation of the glass material, chromatic aberration.