CN106932890B

CN106932890B - Intelligent vehicle-mounted wide-angle lens

Info

Publication number: CN106932890B
Application number: CN201710308249.2A
Authority: CN
Inventors: 汪俊朋
Original assignee: Weihai Jiarui Optoelectronic Technology Co ltd
Current assignee: Weihai Jiarui Optoelectronic Technology Co ltd
Priority date: 2017-05-04
Filing date: 2017-05-04
Publication date: 2022-05-13
Anticipated expiration: 2037-05-04
Also published as: CN106932890A

Abstract

The invention discloses an intelligent vehicle-mounted wide-angle lens which comprises a first lens group and a second lens group; a diaphragm is arranged between the first lens group and the second lens group; an optical filter is arranged between the second lens group and the image surface; the first lens group comprises a meniscus lens I with negative focal power and a convex surface facing to an object space, a double convex lens II with negative focal power and a double convex lens III with positive focal power; the second lens group comprises a cemented lens formed by bonding a fourth lens and a fifth lens and a double convex lens sixth lens with positive focal power; the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially and coaxially arranged between the object plane and the image plane. The optical lens with high field angle, good aberration characteristic, high image resolution and high definition can be produced by only six glass spherical lenses, the shooting dead angle is not easy to occur in the monitoring and shooting process, and the monitoring range is large.

Description

Intelligent vehicle-mounted wide-angle lens

Technical Field

The invention relates to a wide-angle lens, in particular to an intelligent vehicle-mounted wide-angle lens, and belongs to the technical field of optical imaging.

Background

A wide-angle lens is a lens that can photograph an image with a wider angle of view in an imaging range, and is widely used in an imaging device for monitoring or vehicle mounting in general due to the characteristic of a wide angle of view. In recent years, product lenses in the fields of mobile devices, vehicle devices, sports devices, security monitoring devices, and the like have been developed toward light, thin, and short design trends; in the process of miniaturization of the lens module, people also want the lens to have higher pixels and view angles, so as to be convenient for capturing a wider view field. The field angle of the existing intelligent vehicle-mounted photographing lens is not high enough, so that the problems of too small photographing monitoring range, a plurality of photographing dead angles and the like are easily caused, the clear and effective recording and restoring process is not facilitated, and the requirements of the intelligent vehicle-mounted lens on higher and higher image resolution and definition can not be met. Therefore, how to design a smart vehicle-mounted wide-angle lens with small size, large field angle and high imaging quality has become an issue of intense research by those skilled in the art.

Disclosure of Invention

In order to overcome the defects of the technology, the invention provides an intelligent vehicle-mounted wide-angle lens.

In order to solve the technical problems, the invention adopts the technical scheme that: an intelligent vehicle-mounted wide-angle lens comprises a diaphragm, an optical filter, a first lens group and a second lens group; the diaphragm is arranged between the first lens group and the second lens group; the optical filter is arranged between the second lens group and the image surface; protective glass is arranged between the optical filter and the image plane;

the first lens group has a negative focal length and comprises a meniscus lens I lens with negative focal power and a convex surface facing an object space, a double-convex lens II lens with negative focal power and a double-convex lens III lens with positive focal power;

the second lens group has a positive focal length and comprises a cemented lens formed by bonding a fourth lens and a fifth lens and a double convex lens sixth lens with positive focal power; the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially and coaxially arranged between the object plane and the image plane;

the focal length of the whole optical system of the wide-angle lens is f; the combined focal lengths of the first lens group and the second lens group are fa and fb respectively; focal lengths of the first lens, the second lens, the third lens, the cemented lens and the sixth lens are f1, f2, f3, f4-5 and f6 respectively;

the combined focal length ranges of the first lens group and the second lens group are respectively 12< | fa |/f <15 and 1.8< | fb |/f < 2; the focal length ranges of the first lens, the second lens, the third lens, the cemented lens and the sixth lens are respectively as follows: 0.5< | f1|/f <3.5, 1< | f2|/f <2.5, 1< | f3|/f <2.5, 4< | f4-5|/f <6, 2.5< | f6|/f < 3.5.

The distance from the object space surface of the first lens to the image plane along the optical axis direction is D, and the value range of D is 0.05< | D/fa | <1 and 1.5< | D/fb | < 5.

The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all glass spherical lenses.

The total optical length TTL of the wide-angle lens is less than or equal to 21.5 mm.

The refractive index Nd of the first lens is 1.4< Nd <1.6, and the dispersion ratio Vd is 65< Vd < 66;

the refractive index Nd of the second lens is 1.4< Nd <1.6, and the dispersion ratio Vd is 65< Vd < 66;

the refractive index Nd of the third lens is 1.7< Nd <1.9, and the dispersion ratio Vd is 31< Vd < 33;

the refractive index Nd of the fourth lens is 1.6< Nd <1.8, and the dispersion ratio Vd is 54< Vd < 57;

the refractive index Nd of the fifth lens is 1.9< Nd <2.0, and the dispersion ratio Vd is 19< Vd < 21;

the refractive index Nd of the sixth lens is 1.8< Nd <1.9, and the dispersion Vd is 41< Vd < 43.

The optical lens with high field angle, good aberration characteristic, high image resolution and definition can be produced by only six glass spherical lenses, the shooting dead angle is not easy to appear in the monitoring and shooting process, the monitoring range is large, and therefore the optical lens is more beneficial to clearly and effectively restoring the incident process and is particularly used as an intelligent vehicle-mounted wide-angle lens. In addition, the invention has simple and compact structure and small lens number, and is beneficial to the miniaturization design of the lens, thereby reducing the production cost.

Drawings

FIG. 1 is a block diagram of the system components of the present invention.

FIG. 2 is a diagram illustrating the path of light entering from the first embodiment.

Fig. 3 is a MTF resolution graph of the first embodiment.

Fig. 4 is an astigmatism graph of the first embodiment.

Fig. 5 is an optical distortion diagram according to the first embodiment.

FIG. 6 is a dot-sequence diagram of the first embodiment.

In the figure: 1. a first lens; 2. a second lens; 3. a third lens; 4. a fourth lens; 5. a fifth lens; 6. a lens number six; 7. an optical filter; 8. protecting glass; 9. an image plane; 10. a diaphragm; 11. and (4) an object plane.

Detailed Description

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

As shown in fig. 1, the present invention is provided with a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6 coaxially and sequentially from an object plane 11 to an image plane 9; the first lens 1, the second lens 2 and the third lens 3 jointly form a first lens group with negative focal power, and are used for receiving external light rays with the maximum field angle and correcting partial aberration; and the fourth lens 4, the fifth lens 5 and the sixth lens 6 jointly form a second lens group with positive focal power, and are used for receiving the light of the first lens group and converging the light on an image plane.

The wide angle lens further includes a stop 10, and the stop 10 is disposed between the first lens group and the second lens group to limit the amount of light flux passing through the first lens group optically upon entering the second lens group. An optical filter 7 and a protective glass 8 are sequentially arranged between the sixth lens 6 and the image surface 9, so that noise light outside a designed waveband can be filtered, the optical efficiency is further improved, and the optimal imaging effect is realized.

The focal length of the whole optical system of the wide-angle lens is f; the combined focal lengths fa, fb of the first lens group and the second lens group respectively satisfy the following conditions:

1)12< | fa |/f < 15; fa in this range can increase the angle of view of the optical lens and facilitate the processing of the first lens;

2)1.8< | fb |/f < 2; fb within this range, the high-order aberration of the system can be reduced to improve the imaging quality and simultaneously the distortion is corrected to improve the brightness of the periphery of the image;

the first lens 1 is a meniscus lens with a negative focal power, wherein the object side surface of the meniscus lens is convex and the image side surface of the meniscus lens is concave, and the meniscus lens is used for increasing the field angle of the wide-angle lens; the second lens 2 has negative focal power, is a lens with concave object side surface and concave image side surface, corrects aberration generated by the light passing through the first lens 1, and transmits the light to the third lens 3; the third lens 3 has positive focal power, is a lens with convex surfaces on the object side surface and the image side surface, is used for correcting aberration generated by light rays passing through the second lens 2, and converges the light rays passing through the diaphragm and transmits the converged light rays to the fourth lens 4; the fourth lens 4 and the fifth lens 5 are mutually bonded to form a cemented lens group which has positive focal power, can realize minimum chromatic aberration, simultaneously reduce spherical aberration, converge light and transmit the light to the sixth lens 6; the sixth lens 6 has positive focal power, and is a biconvex lens with an object side surface and an image side surface, so as to correct aberration generated by light rays passing through the cemented lens group and image the light rays onto an image surface 9.

Focal lengths of the first lens 1, the second lens 2, the third lens 3, the cemented lens and the sixth lens 6 are respectively represented as f1, f2, f3, f4-5 and f 6; the focal length range of each lens is:

3)0.5<|f1|/f<3.5；

4)1<|f2|/f<2.5；

5)1<|f3|/f<2.5；

6)4<|f4-5|/f<6；

7)2.5<|f6|/f<3.5。

further, a distance from the object side surface of the first lens 1 to the image plane 9 in the optical axis direction is represented by D, and the range of the value of D is 0.05< | D/fa | <1 and 1.5< | D/fb | < 5.

All optical lenses in the lens adopt glass spherical lenses, so that the lens has good aberration characteristic and good imaging quality, and can effectively reduce the processing difficulty and the production cost.

The refractive index Nd of the first lens 1 is 1.4< Nd <1.6, and the dispersion ratio Vd is 65< Vd < 66;

the refractive index Nd of the second lens 2 is 1.4< Nd <1.6, and the dispersion ratio Vd is 65< Vd < 66;

the refractive index Nd of the third lens 3 is 1.7< Nd <1.9, and the dispersion ratio Vd is 31< Vd < 33;

the refractive index Nd of the fourth lens 4 is 1.6< Nd <1.8, and the dispersion ratio Vd is 54< Vd < 57;

the refractive index Nd of the fifth lens 5 is 1.9< Nd <2.0, and the dispersion ratio Vd is 19< Vd < 21;

the refractive index Nd of the sixth lens 6 is 1.8< Nd <1.9, and the dispersion Vd is 41< Vd < 43.

The optical properties of the invention are explained in further detail below by means of a specific example.

In this embodiment, specific optical parameters of the wide-angle lens are shown in table 1:

TABLE 1

Surface name	Surface type	Radius of curved surface	Thickness of	Refractive index	Coefficient of dispersion
						First lens	Spherical surface	24.4159	0.7	1.52	64
	Spherical surface	3.8026	3.84
						Second lens	Spherical surface	-11.4259	1	1.52	64
	Spherical surface	3.58	0.854
						Third lens	Spherical surface	5.155	1.919	1.85	32
	Spherical surface	-26.3044	1.4637
						Diaphragm	Spherical surface	1.00E+18	0.713
Fourth lens	Spherical surface	-57.4798	2.086	1.7	55
						Lens with five lenses	Spherical surface	-2.3436	0.8	1.92	20
	Spherical surface	-5.4986	0.2471
						No. six lens	Spherical surface	15.4895	1.996	1.84	42
	Spherical surface	-14.9437	0.4
						Optical filter	Spherical surface	Infinite number of elements	0.3	1.52	64.1
	Spherical surface	Infinite number of elements	0.1
						Cover glass	Spherical surface	Infinite number of elements	0.4	1.52	64.1

In this embodiment, | fa |/f |, 1.95, | f1|/f 2.99, | f2|/f 1.75, | f3|/f 1.76, | f4-5|/f 5.13, | f6|/f 3.18, | D/fa | 0.52, | D/fb | 3.75.

Fig. 2 shows the path of light entering from this embodiment. The optical properties of the present invention are verified by specific experiments.

(1) The MTF resolution curve of the present embodiment is shown in fig. 3, in which the abscissa represents the line pair/spatial frequency per millimeter (lp/mm) and the ordinate represents the MTF value. As can be seen from FIG. 3, the present embodiment exhibits better contrast within the spatial frequency of 140lp/mm, and the comprehensive resolution level thereof is higher, which also means that the definition of the shot picture is higher; and the whole MTF drop is smooth, and the high-frequency part and the low-frequency part can be effectively balanced.

(2) The astigmatism curve of the present embodiment is shown in fig. 4, wherein ASTIGMATIC FIELD measures represents the astigmatism curve, ANGLE represents the ANGLE, and focus (mm) represents the focus (mm). As can be seen from the figure, astigmatism of the present embodiment is effectively controlled, and the optical distortion level can be reflected to a certain extent.

(3) As shown in fig. 5, when the global design is in a full view, the maximum DISTORTION of the present embodiment is only-60%, and the DISTORTION correction is good, so that the present embodiment is suitable for being used as an intelligent vehicle-mounted wide-angle lens.

(4) The dot diagram of the optical system of the present embodiment in different FIELDs of view (FIELD) is shown in fig. 6, and in fig. 6, the imaging points in each FIELD of view are almost converged into an ideal point, which indicates that the present embodiment has good imaging performance.

The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make variations, modifications, additions or substitutions within the technical scope of the present invention.

Claims

1. The utility model provides an on-vehicle wide-angle lens of intelligence, includes diaphragm (10), light filter (7), its characterized in that: the lens also comprises a first lens group and a second lens group; the diaphragm (10) is arranged between the first lens group and the second lens group; the optical filter (7) is arranged between the second lens group and the image surface (9); protective glass (8) is arranged between the optical filter (7) and the image surface (9);

the first lens group has a negative focal length and comprises a first meniscus lens (1) with negative focal power and a convex surface facing an object space, a second biconcave lens (2) with negative focal power and a third biconvex lens (3) with positive focal power;

the second lens group has a positive focal length and comprises a cemented lens formed by bonding a fourth lens (4) and a fifth lens (5) and a double convex lens six lens (6) with positive focal power; the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) are sequentially and coaxially arranged between the object plane (11) and the image plane (9);

the focal length of the whole optical system of the wide-angle lens is f; the combined focal lengths of the first lens group and the second lens group are fa and fb respectively; focal lengths of the first lens (1), the second lens (2), the third lens (3), the cemented lens and the sixth lens (6) are f1, f2, f3, f4-5 and f6 respectively;

the combined focal length ranges of the first lens group and the second lens group are respectively 12< | fa |/f <15 and 1.8< | fb |/f < 2; the focal length ranges of the first lens (1), the second lens (2), the third lens (3), the cemented lens and the sixth lens (6) are respectively as follows: 0.5< | f1|/f <3.5, 1< | f2|/f <2.5, 1< | f3|/f <2.5, 4< | f4-5|/f <6, 2.5< | f6|/f < 3.5.

2. The intelligent vehicle-mounted wide-angle lens according to claim 1, wherein: the distance between the object space surface of the first lens (1) and the image plane (9) along the optical axis direction is D, and the value range of D is 0.05< | D/fa | <1 and 1.5< | D/fb | < 5.

3. The intelligent vehicle-mounted wide-angle lens according to claim 1, wherein: the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) are all glass spherical lenses.

4. The intelligent vehicle-mounted wide-angle lens according to claim 1, wherein: and the total optical length TTL of the wide-angle lens is less than or equal to 21.5 mm.

5. The intelligent vehicle-mounted wide-angle lens according to claim 1 or 3, wherein:

the refractive index Nd of the first lens (1) is 1.4< Nd <1.6, and the dispersion ratio Vd is 65< Vd < 66;

the refractive index Nd of the second lens (2) is 1.4< Nd <1.6, and the dispersion ratio Vd is 65< Vd < 66;

the refractive index Nd of the third lens (3) is 1.7< Nd <1.9, and the dispersion ratio Vd is 31< Vd < 33;

the refractive index Nd of the fourth lens (4) is 1.6< Nd <1.8, and the dispersion ratio Vd is 54< Vd < 57;

the refractive index Nd of the fifth lens (5) is 1.9< Nd <2.0, and the dispersion ratio Vd is 19< Vd < 21;

the refractive index Nd of the sixth lens (6) is 1.8< Nd <1.9, and the dispersion ratio Vd is 41< Vd < 43.