CN110412752B

CN110412752B - Wide-angle lens

Info

Publication number: CN110412752B
Application number: CN201910844407.5A
Authority: CN
Inventors: 尚金倩; 贺保丁; 邹文镔; 梁伟朝
Original assignee: Sunny Optics Zhongshan Co Ltd
Current assignee: Sunny Optics Zhongshan Co Ltd
Priority date: 2019-09-06
Filing date: 2019-09-06
Publication date: 2024-06-28
Anticipated expiration: 2039-09-06
Also published as: CN110412752A

Abstract

The invention relates to a wide-angle lens, which comprises the following components in sequence from an object side to an image side along an optical axis: a first lens (L1) having negative optical power, a second lens (L2) having negative optical power, a third lens (L3) having negative optical power, a STOP (STOP), a fourth lens (L4) having positive optical power, a fifth lens (L5) having positive optical power, a sixth lens (L6) having negative optical power, and a seventh lens (L7) having positive optical power; the fifth lens (L5) and the sixth lens (L6) are cemented to form a cemented lens group having negative optical power. The lens can meet the requirements of small volume, no virtual focus in the temperature range of-40 ℃ to 85 ℃ and the like, and has high relative brightness, high resolution and good shooting effect.

Description

Wide-angle lens

Technical Field

The invention relates to the field of optical imaging, in particular to a wide-angle lens.

Background

With the rapid development of technology, the resolution of the optical lens is increasingly required. Most of wide-angle lenses in the current market cannot have small volume and no thermalization on the premise of meeting high definition. Therefore, the invention aims to provide a solution for the defects, and provides a wide-angle lens which is small in size, does not have virtual focus in the temperature range of-40-85 ℃ and has definition reaching more than 2000 ten thousand pixels.

Disclosure of Invention

The present invention is directed to solving the above problems and providing a wide-angle lens.

In order to achieve the above object, the present invention provides a wide-angle lens including, in order from an object side to an image side along an optical axis: a first lens having negative optical power, a second lens having negative optical power, a third lens having negative optical power, a stop, a fourth lens having positive optical power, a fifth lens having positive optical power, a sixth lens having negative optical power, and a seventh lens having positive optical power;

The fifth lens and the sixth lens are glued to form a glued lens group with negative focal power.

According to one aspect of the present invention, the first lens is a convex-concave lens, the second lens is a convex-concave lens, the third lens is a concave-convex lens, the fourth lens is a convex-convex lens, the fifth lens is a convex-convex lens, the sixth lens is a concave-concave lens, and the seventh lens is a convex-convex lens.

According to one aspect of the present invention, the first lens, the fourth lens, the fifth lens, and the sixth lens are spherical lenses;

the second lens, the third lens and the seventh lens are aspherical lenses.

According to one aspect of the present invention, the image sensor further includes a chip protection glass, and the chip protection glass is located between the seventh lens and the image plane.

According to one aspect of the present invention, a focal length fb of a cemented lens group composed by the fifth lens and the sixth lens and an effective focal length f of the lens satisfy the relation: -3.4 < fb/f < 2.9.

According to one aspect of the present invention, the effective focal length f of the lens and the distance D from the object side surface to the image side surface of the first lens satisfy the following relation: the f/D is more than or equal to 0.14.

According to one aspect of the invention, the effective focal length f and half-image height h of the lens satisfy the relationship: f/h is less than or equal to 0.75.

According to one aspect of the present invention, the distance D between the lens back focal point D and the object side surface of the first lens element to the image plane satisfies the relationship: D/D is more than or equal to 0.19.

According to one aspect of the invention, the chief ray angle CRA of the maximum field of view of the lens satisfies the relationship: CRA is less than or equal to 17 degrees.

According to one aspect of the present invention, the relative refractive index temperature coefficient dn/dt of at least one of the fourth lens, the fifth lens and the seventh lens satisfies the following relationship: dn/dt is less than or equal to 0.

According to one aspect of the present invention, at least two lenses are made of low dispersion glass, and Abbe number VD satisfies the following relationship: VD is more than or equal to 60.

According to an aspect of the present invention, aberration is effectively corrected by optimally configuring the concavities and convexities and positive and negative powers of the respective lenses. And wide-angle image capturing at a horizontal field angle of 134 ° can be achieved.

According to an aspect of the present invention, a focal length fb of a cemented lens group formed by a fifth lens and a sixth lens and an effective focal length f of a lens satisfy the relationship: -3.4 < fb/f < 2.9. The effective focal length f of the lens and the distance D from the object side surface of the first lens to the image surface satisfy the following relation: the f/D is more than or equal to 0.14. The effective focal length f and half image height h of the lens satisfy the relation: f/h is less than or equal to 0.75. The distance D between the lens back focal point D and the object side surface of the first lens and the image surface satisfies the relation: D/D is more than or equal to 0.19. The chief ray angle CRA of the maximum field of view of the lens satisfies the relation: CRA is less than or equal to 17 degrees. The height of the lens image surface can reach phi 8.0mm, CRA is less than or equal to 17 degrees, and the lens can be adapted to a plurality of sensors, has wide application prospect and improves market competitiveness.

According to an aspect of the present invention, spherical and aspherical lens combinations are used, and the relative refractive index temperature coefficient dn/dt of at least one of the fourth lens L4, the fifth lens L5 and the seventh lens L7 satisfies the following relationship: dn/dt is less than or equal to 0. The lens can be free from virtual focus in the temperature range of-40 ℃ to 85 ℃ and is applicable to different environments. And can realize high resolution of over 2000 ten thousand, uniform overall illumination and high brightness (over 60% relative illumination). The total length of the lens is within 18.5mm, the defect of large volume of the existing lens is overcome, and the lens single part and assembly tolerance are good, so that the lens has good manufacturability.

According to one embodiment of the present invention, at least two lenses in the lens are made of low dispersion glass, and the abbe number VD satisfies the following relationship: VD is more than or equal to 60. The chromatic aberration is corrected by the optical system, and high resolution is realized.

Drawings

Fig. 1 is a block diagram schematically showing a wide-angle lens according to a first embodiment of the present invention;

Fig. 2 is an MTF diagram schematically showing a wide-angle lens according to a first embodiment of the present invention;

fig. 3 is a view schematically showing a Through-Focus-MTF at a frequency of 225lp/mm of a wide-angle lens according to a first embodiment of the present invention;

FIG. 4 is a view schematically showing a Through-Focus-MTF at a high temperature of 85℃and a frequency of 225lp/mm for a wide-angle lens according to a first embodiment of the present invention;

FIG. 5 is a schematic representation of a wide-angle lens according to a first embodiment of the present invention at a low temperature of-40℃and a frequency of 225lp/mm Through-Focus-MTF;

Fig. 6 is a block diagram schematically showing a wide-angle lens according to a second embodiment of the present invention;

Fig. 7 is an MTF diagram schematically showing a wide-angle lens according to a second embodiment of the present invention;

Fig. 8 is a view schematically showing a Through-Focus-MTF at a frequency of 225lp/mm of a wide-angle lens according to a second embodiment of the present invention;

FIG. 9 is a view schematically showing a Through-Focus-MTF at a high temperature of 85℃and a frequency of 225lp/mm for a wide-angle lens according to a second embodiment of the present invention;

FIG. 10 is a schematic representation of a wide-angle lens according to a second embodiment of the present invention at a low temperature of-40℃with a frequency of 225lp/mm Through-Focus-MTF;

Fig. 11 is a block diagram schematically showing a wide-angle lens according to a third embodiment of the present invention;

Fig. 12 is an MTF diagram schematically showing a wide-angle lens according to a third embodiment of the present invention;

fig. 13 is a view schematically showing a Through-Focus-MTF at a frequency of 225lp/mm of a wide-angle lens according to a third embodiment of the present invention;

FIG. 14 is a view schematically showing a Through-Focus-MTF at a high temperature of 85℃and a frequency of 225lp/mm for a wide-angle lens according to a third embodiment of the present invention;

fig. 15 is a schematic view showing a Through-Focus-MTF at a frequency of 225lp/mm at a low temperature of-40 ℃ according to a third embodiment of the present invention;

Fig. 16 is a block diagram schematically showing a wide-angle lens according to a fourth embodiment of the present invention;

fig. 17 is an MTF diagram schematically showing a wide-angle lens according to a fourth embodiment of the present invention;

Fig. 18 is a view schematically showing a Through-Focus-MTF at a frequency of 225lp/mm of a wide-angle lens according to a fourth embodiment of the present invention;

FIG. 19 is a view schematically showing a Through-Focus-MTF at a high temperature of 85℃and a frequency of 225lp/mm for a wide-angle lens according to a fourth embodiment of the present invention;

FIG. 20 is a schematic representation of a wide-angle lens according to a fourth embodiment of the present invention at a low temperature of-40℃at a frequency of 225lp/mm Through-Focus-MTF;

fig. 21 is a block diagram schematically showing a wide-angle lens according to a fifth embodiment of the present invention;

Fig. 22 is an MTF diagram schematically showing a wide-angle lens according to a fifth embodiment of the present invention;

Fig. 23 is a view schematically showing a Through-Focus-MTF at a frequency of 225lp/mm of a wide-angle lens according to a fifth embodiment of the present invention;

FIG. 24 is a view schematically showing a Through-Focus-MTF at a high temperature of 85℃and a frequency of 225lp/mm for a wide-angle lens according to a fifth embodiment of the present invention;

fig. 25 is a schematic view showing a Through-Focus-MTF at a low temperature of-40 c and a frequency of 225lp/mm according to a fifth embodiment of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

In describing embodiments of the present invention, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in terms of orientation or positional relationship shown in the drawings for convenience of description and simplicity of description only, and do not denote or imply that the devices or elements in question must have a particular orientation, be constructed and operated in a particular orientation, so that the above terms are not to be construed as limiting the invention.

The present invention will be described in detail below with reference to the drawings and the specific embodiments, which are not described in detail herein, but the embodiments of the present invention are not limited to the following embodiments.

Fig. 1 is a block diagram schematically showing a wide-angle lens according to an embodiment of the present invention. As shown in fig. 1, the wide-angle lens of the present invention includes, in order from an object side to an image side along an optical axis: a first lens L1 having negative optical power, a second lens L2 having negative optical power, a third lens L3 having negative optical power, a STOP, a fourth lens L4 having positive optical power, a fifth lens L5 having positive optical power, a sixth lens L6 having negative optical power, and a seventh lens L7 having positive optical power. Wherein the fifth lens L5 and the sixth lens L6 are cemented to form a cemented lens group having negative optical power.

In the present invention, the first lens L1 is a convex-concave lens, the second lens L2 is a convex-concave lens, the third lens L3 is a concave-convex lens, the fourth lens L4 is a convex-convex lens, the fifth lens L5 is a convex-convex lens, the sixth lens L6 is a concave-concave lens, and the seventh lens L7 is a convex-convex lens.

In the present invention, the first lens L1, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are spherical lenses. The second lens L2, the third lens L3, and the seventh lens L7 are aspherical lenses.

In the invention, the lens further comprises a chip (sensor) protection glass CG, and the chip protection glass CG is positioned between the seventh lens L7 and the image plane.

In addition, the focal length fb of the cemented lens group formed by the fifth lens L5 and the sixth lens L6 (i.e., the combined focal length of the fifth lens L5 and the sixth lens L6) and the effective focal length f of the lens barrel satisfy the relationship: -3.4 < fb/f < 2.9. The effective focal length f of the lens and the distance D from the object side surface to the image surface of the first lens L1 satisfy the following relation: the f/D is more than or equal to 0.14. The effective focal length f and half image height h of the lens satisfy the relation: f/h is less than or equal to 0.75. The lens back focal length D (i.e., the distance from the image side surface of the seventh lens element L7 to the image plane) and the distance D from the object side surface of the first lens element L1 to the image plane satisfy the following relationship: D/D is more than or equal to 0.19. The chief ray angle CRA of the maximum field of view of the lens satisfies the relation: CRA is less than or equal to 17 degrees.

In the present invention, the relative refractive index temperature coefficient dn/dt of at least one of the fourth lens L4, the fifth lens L5 and the seventh lens L7 satisfies the following relationship: dn/dt is less than or equal to 0.

In the invention, the spherical lenses are all made of glass, the aspherical lenses can be made of glass or plastic, but the materials of at least two lenses in the lens are low-dispersion glass, and Abbe number VD satisfies the following relation: VD is more than or equal to 60.

Through the design, the lens can realize high resolution of over 2000 ten thousand, uniform overall illumination and high brightness (the relative illumination is over 60 percent). The aberration is effectively corrected by optimally configuring the positive and negative focal powers of the lenses. The height of the image surface can reach phi 8.0mm, and the CRA is less than or equal to 17 degrees, so that the image surface can be adapted to a plurality of sensors, the application prospect is wide, and the market competitiveness is improved. And can realize no virtual focus in the temperature range of-40 ℃ to 85 ℃ and can be suitable for different environments. And wide-angle image capturing of 134 degrees of horizontal field angle can be realized. The total length of the lens is within 18.5mm, the defect of large volume of the traditional lens is overcome, and the lens single part and assembly tolerance are good, so that the lens has good manufacturability.

The following sets of five embodiments are given to specifically explain the wide-angle lens according to the present invention according to the above-described arrangement of the present invention. Since the wide-angle lens according to the present invention has seven lenses in total, in which the fifth lens L5 and the sixth lens L6 constitute a cemented lens group, the seven lenses are added with the STOP, the chip protection glass CG, and the IMAGE plane IMAGE total 17 planes. The 17 surfaces are arranged in sequence according to the structural sequence of the invention, for convenience of description, the 17 surfaces are numbered S1 to S17, wherein S7 where the diaphragm surface is located is replaced by STO, S11 is a bonding surface of the fifth lens L5 and the sixth lens L6, S0 is an object surface, and the thickness thereof is the object distance. In the following embodiments, the aspherical lens surface satisfies the following formula:

Wherein z is the axial distance from the curved surface to the vertex at the position with the height h perpendicular to the optical axis along the optical axis direction; c represents the curvature at the apex of the aspherical curved surface; k is a conic coefficient; a4, A6, A8, A10, A12, A14 and A16 are respectively four-order, six-order eighth, tenth, fourteen, and fourteen sixteen orders · · aspheric coefficients.

Five sets of embodiment data are shown in table 1 below:

TABLE 1

Fig. 1 is a block diagram schematically showing a wide-angle lens according to a first embodiment of the present invention. An embodiment is described based on the configuration of the optical system shown in fig. 1.

Embodiment one:

F number (i.e., inverse of relative pore size) is 2.6; the total length of the lens is 18mm; the angle of view is 155 °.

Table 2 is a table of parameters for embodiment one, including surface type, radius of curvature, thickness, refractive index of material, abbe number:

Face number	Surface type	R value	Thickness of (L)	Refractive index	Abbe number
						S0(OBJ)	Spherical surface	Infinity	1200
S1	Spherical surface	11.5340	0.6	1.76	54.7
						S2	Spherical surface	3.2841	1.2359
S3	Aspherical surface	5.1293	0.7	1.53	81.6
						S4	Aspherical surface	3.5258	1.4687
S5	Aspherical surface	-8.2887	0.94	1.75	45.1
						S6	Aspherical surface	-19.0567	0.9624
STO	Spherical surface	Infinity	0.0972
						S8	Spherical surface	31.4914	2.02	1.53	54.7
S9	Spherical surface	-3.3727	0.9197
						S10	Spherical surface	9.8426	2.27	1.46	80.2
S11	Spherical surface	-3.5012	0.5	1.78	30.1
						S12	Spherical surface	7.9529	0.0978
S13	Aspherical surface	16.8904	2.6121	1.56	71.6
						S14	Aspherical surface	-14.5389	2.6477
S15	Spherical surface	Infinity	0.5	1.52	64.2
						S16	Spherical surface	Infinity	0.778
S17	Spherical surface	Infinity	-	-	-

TABLE 2

In this embodiment, the aspherical data is shown in table 3 below, where K is the quadric constant of the surface, A, B, C, D, E, F, G is the aspherical coefficients of fourth, sixth, eighth, tenth, fourteen, sixteen steps, respectively:

TABLE 3 Table 3

Fig. 2 to 5 are MTF diagrams schematically showing a wide-angle lens according to a first embodiment of the present invention, respectively; a Through-Focus-MTF plot with a frequency of 225lp/mm for a wide-angle lens according to an embodiment of the present invention; according to the wide-angle lens, a Through-Focus-MTF diagram with the frequency of 225lp/mm is formed at the high temperature of 85 ℃; according to the wide-angle lens, the frequency is 225lp/mm at the low temperature of-40 ℃.

By optimizing the above parameter values, the lens of the present embodiment realizes a small-volume, high-resolution characteristic, and can realize athermalization, with a characteristic of no virtual focus in a temperature range of-40 ℃ to 85 ℃. Can meet the excellent imaging effect under different temperature environments and has high market competitiveness.

Fig. 6 is a block diagram schematically showing a wide-angle lens according to a second embodiment of the present invention. The second embodiment will be described based on the configuration of the optical system shown in fig. 6.

Embodiment two:

F number is 2.6; the total length of the lens is 17.5mm; the angle of view is 155 °.

Table 4 is a table of two parameters of the embodiment, including surface type, radius of curvature, thickness, refractive index of the material, abbe number:

Face number	Surface type	R value	Thickness of (L)	Refractive index	Abbe number
						S0(OBJ)	Spherical surface	Infinity	Infinity
S1	Spherical surface	11.52	1.1899	1.7	56.2
						S2	Spherical surface	3.0957	1.2235
S3	Aspherical surface	7.4381	0.3838	1.5	64.8
						S4	Aspherical surface	2.6448	1.4768
S5	Aspherical surface	-6.3769	0.9724	1.86	36.6
						S6	Aspherical surface	-7.8151	0.8773
STO	Spherical surface	Infinity	0.0996
						S8	Spherical surface	20.5905	2.0212	1.73	54.7
S9	Spherical surface	-3.2709	0.6531
						S10	Spherical surface	9.2036	2.0652	1.46	90.2
S11	Spherical surface	-3.1449	0.5070	1.70	30.1
						S12	Spherical surface	7.777	0.1421
S13	Aspherical surface	6.6802	2.0486	1.46	90.2
						S14	Aspherical surface	-4.3224	2.6344
S15	Spherical surface	Infinity	0.5	1.52	64.2
						S16	Spherical surface	Infinity	0.878
S17	Spherical surface	Infinity	-	-	-

TABLE 4 Table 4

In this embodiment, the aspherical data is shown in table 5 below, where K is the quadric constant of the surface, A, B, C, D, E, F, G is the aspherical coefficients of fourth, sixth, eighth, tenth, fourteen, sixteen steps, respectively:

TABLE 5

Fig. 7 to 10 are MTF diagrams schematically showing a wide-angle lens according to a second embodiment of the present invention, respectively; a Through-Focus-MTF plot with a frequency of 225lp/mm for a wide-angle lens according to a second embodiment of the present invention; according to the wide-angle lens in the second embodiment of the invention, the frequency is 225lp/mm of a Through-Focus-MTF diagram at the high temperature of 85 ℃; the wide-angle lens according to the second embodiment of the present invention has a Through-Focus-MTF of 225lp/mm at a low temperature of-40 ℃.

Fig. 11 is a block diagram schematically showing a wide-angle lens according to a third embodiment of the present invention. The third embodiment is described based on the optical system configuration shown in fig. 11.

Embodiment III:

f number is 2.8; the total length of the lens is 18.34mm; the angle of view is 150.

Table 6 is a table of parameters for embodiment three, including surface type, radius of curvature, thickness, refractive index of the material, abbe number:

TABLE 6

In this embodiment, the aspherical data is shown in table 7 below, where K is the quadric constant of the surface, A, B, C, D, E, F, G is the aspherical coefficients of fourth, sixth, eighth, tenth, fourteen, sixteen steps, respectively:

TABLE 7

Fig. 12 to 15 are MTF diagrams schematically showing a wide-angle lens according to a third embodiment of the present invention, respectively; a Through-Focus-MTF plot with a frequency of 225lp/mm for a wide-angle lens according to a third embodiment of the present invention; a wide-angle lens according to a third embodiment of the present invention has a Through-Focus-MTF map with a frequency of 225lp/mm at a high temperature of 85 ℃; the wide-angle lens according to the third embodiment of the present invention has a Through-Focus-MTF of 225lp/mm at a low temperature of-40 ℃.

Fig. 16 is a block diagram schematically showing a wide-angle lens according to a fourth embodiment of the present invention. The fourth embodiment is described based on the optical system configuration shown in fig. 16.

Embodiment four:

F number is 2.4; the total length of the lens is 18.0mm; the angle of view is 130.

Table 8 is a table of parameters for the fourth embodiment, including surface type, radius of curvature, thickness, refractive index of material, abbe number:

Face number	Surface type	R value	Thickness of (L)	Refractive index	Abbe number
						S0(OBJ)	Spherical surface	Infinity	Infinity
S1	Spherical surface	9.0033	1.5226	1.68	54.7
						S2	Spherical surface	3.1541	1.3385
S3	Aspherical surface	6.3632	0.6	1.49	91.0
						S4	Aspherical surface	2.4842	1.7232
S5	Aspherical surface	-5.8092	1.1229	1.86	38.3
						S6	Aspherical surface	-8.3514	1.1106
STO	Spherical surface	Infinity	0.6194
						S8	Spherical surface	21.0573	1.2930	1.73	54.7
S9	Spherical surface	-3.6117	0.1537
						S10	Spherical surface	9.1881	2.0590	1.46	90.2
S11	Spherical surface	-3.0700	0.6011	1.70	30.1
						S12	Spherical surface	7.9661	0.1531
S13	Aspherical surface	7.4825	1.9994	1.50	81.6
						S14	Aspherical surface	-4.7257	2.8259
S15	Spherical surface	Infinity	0.5	1.52	64.2
						S16	Spherical surface	Infinity	0.3780
S17	Spherical surface	Infinity	-	-	-

TABLE 8

In this embodiment, the aspherical data is shown in table 9 below, where K is the quadric constant of the surface, A, B, C, D, E, F, G is the aspherical coefficients of fourth, sixth, eighth, tenth, fourteen, sixteen steps, respectively:

TABLE 9

Fig. 17 to 20 are MTF diagrams schematically showing a wide-angle lens according to a fourth embodiment of the present invention, respectively; a Through-Focus-MTF plot with a frequency of 225lp/mm for a wide-angle lens according to a fourth embodiment of the present invention; a wide-angle lens according to a fourth embodiment of the present invention has a Through-Focus-MTF map with a frequency of 225lp/mm at a high temperature of 85 ℃; the wide-angle lens according to the fourth embodiment of the present invention has a Through-Focus-MTF of 225lp/mm at a low temperature of-40 ℃.

Fig. 21 is a block diagram schematically showing a wide-angle lens according to a fifth embodiment of the present invention. The fifth embodiment is described based on the optical system configuration shown in fig. 21.

Fifth embodiment:

F number is 2.6; the total length of the lens is 18.2mm; the angle of view is 170.

Table 10 is a table of parameters of embodiment five, including surface type, radius of curvature, thickness, refractive index of material, abbe number:

Table 10

In this embodiment, the aspherical data is shown in table 11 below, where K is the quadric constant of the surface, A, B, C, D, E, F, G is the aspherical coefficients of fourth, sixth, eighth, tenth, fourteen, sixteen steps, respectively:

TABLE 11

Fig. 22 to 25 are MTF diagrams schematically showing a wide-angle lens according to a fifth embodiment of the present invention, respectively; a Through-Focus-MTF plot with a frequency of 225lp/mm for a wide-angle lens according to a fifth embodiment of the present invention; a wide-angle lens according to a fifth embodiment of the present invention has a Through-Focus-MTF map with a frequency of 225lp/mm at a high temperature of 85 ℃; the wide-angle lens according to the fifth embodiment of the present invention has a Through-Focus-MTF of 225lp/mm at a low temperature of-40 ℃.

The above description is only one embodiment of the present invention and is not intended to limit the present invention, and various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A wide-angle lens comprising, in order from an object side to an image side along an optical axis: a first lens (L1) having negative optical power, a second lens (L2) having negative optical power, a third lens (L3) having negative optical power, a STOP (STOP), a fourth lens (L4) having positive optical power, a fifth lens (L5) having positive optical power, a sixth lens (L6) having negative optical power, and a seventh lens (L7) having positive optical power, in total seven lenses;

-said fifth lens (L5) is cemented with said sixth lens (L6) to form a cemented lens group having negative optical power;

The focal length fb of the cemented lens group formed by the fifth lens (L5) and the sixth lens (L6) and the effective focal length f of the lens satisfy the relation: -3.4 < fb/f < 2.9;

the effective focal length f of the lens and the distance D from the object side surface to the image surface of the first lens (L1) satisfy the following relation: the f/D is more than or equal to 0.14.

2. The wide-angle lens according to claim 1, wherein the first lens (L1) is a convex-concave lens, the second lens (L2) is a convex-concave lens, the third lens (L3) is a concave-convex lens, the fourth lens (L4) is a convex-convex lens, the fifth lens (L5) is a convex-convex lens, the sixth lens (L6) is a concave-concave lens, and the seventh lens (L7) is a convex-convex lens.

3. The wide-angle lens according to claim 2, wherein the first lens (L1), the fourth lens (L4), the fifth lens (L5) and the sixth lens (L6) are spherical lenses;

the second lens (L2), the third lens (L3) and the seventh lens (L7) are aspherical lenses.

4. A wide-angle lens according to claim 3, further comprising a chip protection glass (CG) located between the seventh lens (L7) and the image plane.

5. The wide-angle lens as set forth in one of claims 1 to 4, wherein the effective focal length f and half-image height h of the lens satisfy the relation: f/h is less than or equal to 0.75.

6. The wide-angle lens as set forth in one of claims 1 to 4, wherein a distance D between the lens back focal point D and the object-side surface of the first lens element (L1) satisfies the relationship: D/D is more than or equal to 0.19.

7. The wide-angle lens according to one of claims 1 to 4, wherein a chief ray angle CRA of a maximum field of view of the lens satisfies the relation: CRA is less than or equal to 17 degrees.

8. The wide-angle lens according to one of claims 1 to 4, wherein a relative refractive index temperature coefficient dn/dt of at least one of the fourth lens (L4), the fifth lens (L5) and the seventh lens (L7) satisfies the following relation: dn/dt is less than or equal to 0.

9. The wide-angle lens as set forth in any one of claims 1 to 4, wherein at least two lenses are made of low-dispersion glass, and the abbe number VD satisfies the following relationship: VD is more than or equal to 60.