CN109975952B

CN109975952B - Optical lens

Info

Publication number: CN109975952B
Application number: CN201711457297.4A
Authority: CN
Inventors: 陈雨曦; 王东方; 姚波
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2017-12-28
Filing date: 2017-12-28
Publication date: 2021-06-18
Anticipated expiration: 2037-12-28
Also published as: CN109975952A

Abstract

The present application discloses an optical lens, which sequentially comprises, from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens can have negative focal power, and the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens can have negative focal power, and both the object side surface and the image side surface of the second lens are concave; the third lens can have positive focal power, and both the object side surface and the image side surface of the third lens are convex surfaces; the fourth lens element may have a negative focal power, and both the object-side surface and the image-side surface thereof may be concave; the fifth lens can have positive focal power, and both the object side surface and the image side surface of the fifth lens are convex surfaces; the sixth lens element can have a positive focal power, and both the object-side surface and the image-side surface of the sixth lens element are convex; and the seventh lens element can have a positive power, and has a convex object-side surface and a concave image-side surface. According to the optical lens, the effects of miniaturization, long back focal length, small size and the like can be achieved.

Description

Optical lens

Technical Field

The present application relates to an optical lens, and more particularly, to an optical lens including seven lenses.

Background

With the popularization of the use of the vehicle-mounted lens, the market demand and the requirement for the vehicle-mounted lens are on the rise. The common adaptive vehicle-mounted lens needs to meet the requirements of good imaging quality, small lens size and the like. For a specific application field, it is desirable that the stability of the lens is good and the back focus is long, and the lens can be applied to the field of a combined front-view lens. Meanwhile, due to the application specificity, such a lens is usually used for a long time, and the temperature characteristic is also a factor which is emphasized in the application field.

Disclosure of Invention

The present application provides an optical lens that is adaptable for on-board installation and that overcomes, at least in part, at least one of the above-identified deficiencies in the prior art.

An aspect of the present application provides an optical lens that may include, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens can have negative focal power, and the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens can have negative focal power, and both the object side surface and the image side surface of the second lens are concave; the third lens can have positive focal power, and both the object side surface and the image side surface of the third lens are convex surfaces; the fourth lens element may have a negative focal power, and both the object-side surface and the image-side surface thereof may be concave; the fifth lens can have positive focal power, and both the object side surface and the image side surface of the fifth lens are convex surfaces; the sixth lens element can have a positive focal power, and both the object-side surface and the image-side surface of the sixth lens element are convex; and the seventh lens element can have a positive power, and has a convex object-side surface and a concave image-side surface.

In one embodiment, the fourth lens is cemented with the fifth lens.

In one embodiment, a radius of curvature r13 of the object-side surface of the seventh lens, a radius of curvature r14 of the image-side surface of the seventh lens, and a center thickness d13 of the seventh lens may satisfy: r14/(r13-d13) is not less than 1.5 and not more than 6.5.

In one embodiment, a radius of curvature r13 of the object-side surface of the seventh lens and a radius of curvature r14 of the image-side surface of the seventh lens may satisfy: r13/r14 is more than or equal to 0.2 and less than or equal to 0.8.

In one embodiment, the optical lens may further include a stop between the third lens and the fourth lens.

In one embodiment, a distance TTL between a center of an object side surface of the first lens element and an imaging surface of the optical lens on an optical axis and a full-group focal length value F of the optical lens may satisfy: TTL/F is less than or equal to 4.2.

In one embodiment, a distance between a center of an object side surface of the first lens element and an imaging surface of the optical lens on an optical axis, TTL, and a distance between a center of an image side surface of the seventh lens element and the imaging surface of the optical lens on the optical axis, BFL/TTL, may be greater than or equal to 0.3.

In one embodiment, the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens may satisfy: D/h/FOV is less than or equal to 0.03.

Another aspect of the present application provides an optical lens that may include, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. Wherein the first lens, the second lens and the fourth lens may have negative optical power; the third lens, the fifth lens, the sixth lens, and the seventh lens may have positive optical power; the fourth lens can be glued with the fifth lens; and the curvature radius r13 of the object side surface of the seventh lens and the curvature radius r14 of the image side surface of the seventh lens can satisfy that: r13/r14 is more than or equal to 0.2 and less than or equal to 0.8.

In one embodiment, the first lens element has a convex object-side surface and a concave image-side surface.

In one embodiment, the object-side surface and the image-side surface of the second lens are both concave.

In one embodiment, both the object-side surface and the image-side surface of the third lens are convex.

In one embodiment, both the object-side surface and the image-side surface of the fourth lens are concave.

In one embodiment, both the object-side surface and the image-side surface of the fifth lens are convex.

In one embodiment, both the object-side surface and the image-side surface of the sixth lens element are convex.

In one embodiment, the seventh lens element has a convex object-side surface and a concave image-side surface.

The optical lens adopts seven lenses, the focal power of each lens is reasonably distributed and the cemented lens is formed by optimally setting the shape of the lens, and the beneficial effects of long back focal length, small volume, miniaturization, adaptability to environment temperature in a larger range and the like of the optical lens are realized.

Drawings

Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments when taken in conjunction with the accompanying drawings. In the drawings:

fig. 1 is a schematic view showing a structure of an optical lens according to embodiment 1 of the present application;

fig. 2 is a schematic structural view showing an optical lens according to embodiment 2 of the present application; and

fig. 3 is a schematic view showing a structure of an optical lens according to embodiment 3 of the present application.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens, and the first cemented lens may also be referred to as the second cemented lens, without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side surface, and the surface of each lens closest to the image plane is called the image side surface.

It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

The features, principles, and other aspects of the present application are described in detail below.

An optical lens according to an exemplary embodiment of the present application includes, for example, seven lenses having optical power, i.e., a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The seven lenses are arranged in order from the object side to the image side along the optical axis.

The optical lens according to the exemplary embodiment of the present application may further include a photosensitive element disposed on the image plane. Alternatively, the photosensitive element provided to the imaging surface may be a photosensitive coupling element (CCD) or a complementary metal oxide semiconductor element (CMOS).

The first lens element can have a negative power, and can have a convex object-side surface and a concave image-side surface. The first lens is in a meniscus shape which is convex towards the object side, so that large-angle light rays can be collected as far as possible, the light rays enter a rear optical system, and the realization of large-angle resolution at the center is facilitated. In practical application, the vehicle-mounted lens is installed outdoors in a use environment and can be in severe weather such as rain, snow and the like, and the design of the meniscus shape protruding towards the object side is beneficial to the sliding of water drops and reduces the influence on imaging.

The second lens can have a negative optical power, and both the image-side surface and the image-side surface can be concave. The second lens can disperse the light collected by the first lens, adjust the light and reduce the chromatic aberration of the imaging system.

The third lens element can have a positive optical power, and both the object-side surface and the image-side surface can be convex. The third lens can converge the light collected by the second lens, so that the light is stably transited to the rear optical system, and the aperture of the lens is favorably reduced.

The fourth lens element can have a negative optical power, and can have a concave object-side surface and a concave image-side surface.

The fifth lens element can have a positive optical power, and can have a convex object-side surface and a convex image-side surface.

The sixth lens element can have a positive optical power, and can have a convex object-side surface and a convex image-side surface. The sixth lens can further converge the light collected by the fifth lens, and adjust the light, so that the light trend is stably transited to the rear optical system, and the reduction of the rear port diameter is facilitated.

The seventh lens element can have a positive power, and can have a convex object-side surface and a concave image-side surface. The seventh lens is set to have positive focal power, and light rays passing through the sixth lens can be further converged to enable the light rays to be smoothly transited to the rear, so that the reduction of the rear port diameter is facilitated. In addition, the meniscus design of the seventh lens can make the back focal length of the lens longer, which is beneficial to correcting chromatic aberration, improving the resolution quality and improving the relative illumination. Further, the seventh lens may satisfy the conditional expression: 1.5 ≤ r14/(r13-d13) ≤ 6.5 or 0.2 ≤ r13/r14 ≤ 0.8, and more specifically, 2.32 ≤ r14/(r13-d13) ≤ 5.12 or 0.26 ≤ r13/r14 ≤ 0.53 can be further satisfied, wherein r13 is a radius of curvature of an object-side surface of the seventh lens, r14 is a radius of curvature of an image-side surface of the seventh lens, and d13 is a center thickness of the seventh lens, which is advantageous for shortening TTL and improving imaging quality.

In an exemplary embodiment, a diaphragm for limiting light beams may be disposed between the third lens and the fourth lens, for example, to shrink incident light beams, which is beneficial to reducing the aperture of the lens, and at the same time, to achieve the effect of balancing the front and rear aperture of the entire lens, thereby further improving the imaging quality of the lens. It should be understood that the stop position is not limited to between the third lens and the fourth lens, and may be provided at any other position as needed.

As known to those skilled in the art, cemented lenses may be used to minimize or eliminate chromatic aberration. The use of the cemented lens in the optical lens can improve the image quality and reduce the reflection loss of light energy, thereby improving the imaging definition of the lens. In addition, the use of the cemented lens can also simplify the assembly process in the lens manufacturing process.

In an exemplary embodiment, the fourth lens and the fifth lens may be combined into a cemented lens by cementing the image-side surface of the fourth lens with the object-side surface of the fifth lens. By introducing the cemented lens consisting of the fourth lens and the fifth lens, the chromatic aberration influence can be eliminated, the field curvature is reduced, and the coma is corrected; meanwhile, the cemented lens may also retain a part of chromatic aberration to balance the entire chromatic aberration of the optical system. The air space between the two lenses is omitted by gluing the lenses, so that the optical system is compact as a whole, and the requirement of system miniaturization is met. Furthermore, the gluing of the lenses reduces tolerance sensitivity problems of the lens units due to tilt/decentration during assembly.

In the cemented lens, the fourth lens close to the object side has negative focal power, and the fifth lens close to the image side has positive focal power, so that the arrangement is favorable for diverging and converging the front light rays, enabling the front light rays to be smoothly transited to the rear optical system, and being favorable for reducing the total length of the system.

In an exemplary embodiment, TTL/F ≦ 4.2 may be satisfied between the total optical length TTL of the optical lens and the entire set of focal length values F of the optical lens, and more particularly, TTL/F ≦ 4.11 may be further satisfied. Satisfies the condition TTL/F less than or equal to 4.2, and can realize miniaturization.

In an exemplary embodiment, a distance between an optical back focus BFL of the optical lens and an optical total length TTL of the optical lens may satisfy BFL/TTL ≧ 0.3, and more particularly, may further satisfy BFL/TTL ≧ 0.31. When the condition formula BFL/TTL is more than or equal to 0.3, the back focal length of the lens is long enough, the assembly of an effective space can be realized, and the lens is particularly suitable for the lens in the special application field; the optical system can be assembled conveniently, and meanwhile, a space is reserved for the installation and focusing of the optical element, so that the interference between mechanisms is avoided.

In an exemplary embodiment, D/h/FOV ≦ 0.03, more specifically, D/h/FOV ≦ 0.024 may be satisfied between the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens. The conditional expression D/h/FOV is less than or equal to 0.03, and the small caliber at the front end of the lens can be realized.

The optical lens according to the above-described embodiment of the present application has optical characteristics such as a back focal length, a small size, and adaptability to a wide range of environmental temperatures, and can better meet the requirements of an in-vehicle lens.

However, it will be appreciated by those skilled in the art that the number of lenses constituting the lens barrel may be varied to achieve the various results and advantages described in the present specification without departing from the claimed subject matter. For example, although seven lenses are exemplified in the embodiment, the optical lens is not limited to include seven lenses. The optical lens may also include other numbers of lenses, if desired.

Specific examples of an optical lens applicable to the above-described embodiments are further described below with reference to the drawings.

Example 1

An optical lens according to embodiment 1 of the present application is described below with reference to fig. 1. Fig. 1 shows a schematic structural diagram of an optical lens according to embodiment 1 of the present application.

As shown in fig. 1, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

The first lens L1 is a meniscus lens with negative power, with the object side S1 being convex and the image side S2 being concave.

The second lens L2 is a biconcave lens with negative power, and has a concave object-side surface S3 and a concave image-side surface S4.

The third lens L3 is a biconvex lens with positive power, and has a convex object-side surface S5 and a convex image-side surface S6.

The fourth lens L4 is a biconcave lens with negative power, and has a concave object-side surface S8 and a concave image-side surface S9. The fifth lens element L5 is a biconvex lens with positive power, and has a convex object-side surface S9 and a convex image-side surface S10. Wherein, the fourth lens L4 and the fifth lens L5 are cemented to form a cemented lens.

The sixth lens element L6 is a biconvex lens with positive refractive power, and has a convex object-side surface S11 and a convex image-side surface S12.

The seventh lens L7 is a meniscus lens with positive power, with the object side S13 being convex and the image side S14 being concave.

Optionally, the optical lens may further include a filter L8 having an object-side surface S15 and an image-side surface S16, and a protective lens L9 having an object-side surface S17 and an image-side surface S18. Filter L8 can be used to correct for color deviations. The protective lens L9 may be used to protect the image sensing chip on the imaging plane IMA. The light from the object sequentially passes through the respective surfaces S1 to S18 and is finally imaged on the imaging surface S19.

In the optical lens of the present embodiment, a stop STO may be provided between the third lens L3 and the fourth lens L4 to improve the imaging quality.

Table 1 shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 1, where the radius of curvature R and the thickness T are both in units of millimeters (mm).

TABLE 1

The present embodiment adopts seven lenses as an example, and by reasonably distributing the power and the surface type of each lens, the center thickness of each lens and the air space between each lens, the lens has the advantages of small volume, miniaturization, back focal length, adaptability to a wider range of environmental temperature and the like.

Table 2 below gives the total optical length TTL of the optical lens of embodiment 1 (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface S19), the entire group focal length value F of the optical lens, the optical back focus BFL of the optical lens (i.e., the on-axis distance from the center of the image-side surface S14 of the last lens L7 to the imaging surface S19), the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum angle of view of the optical lens, the image height h corresponding to the maximum angle of view of the optical lens, the maximum angle of view FOV of the optical lens, the curvature radius r13 of the object-side surface S13 of the seventh lens L7, the curvature radius r14 of the image-side surface S14 of the seventh lens L7, and the center thickness D13 of the seventh lens L7.

TABLE 2

TTL(mm)	22.070	FOV(°)	60.000
				F(mm)	5.663	r13(mm)	8.652
BFL(mm)	7.776	d13(mm)	1.500
				D(mm)	6.771	r14(mm)	16.600
h(mm)	5.802

In the present embodiment, TTL/F is 3.897 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; the BFL/TTL between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens is 0.352; the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens satisfy D/h/FOV of 0.019; r14/(r13-d13) ═ 2.321 is satisfied among the radius of curvature r13 of the object-side surface S13 of the seventh lens L7, the radius of curvature r14 of the image-side surface S14 of the seventh lens L3, and the center thickness d13 of the seventh lens L7; and r13/r14 is 0.521 between the radius of curvature r13 of the object-side surface S13 of the seventh lens L7 and the radius of curvature r14 of the image-side surface S14 of the seventh lens L3.

Example 2

An optical lens according to embodiment 2 of the present application is described below with reference to fig. 2. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 2 shows a schematic structural diagram of an optical lens according to embodiment 2 of the present application.

As shown in fig. 2, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

Table 3 below shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 2, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 4 below gives the total optical length TTL of the optical lens of embodiment 2 (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface S19), the entire group focal length value F of the optical lens, the optical back focus BFL of the optical lens (i.e., the on-axis distance from the center of the image-side surface S14 of the last lens L7 to the imaging surface S19), the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum angle of view of the optical lens, the image height h corresponding to the maximum angle of view of the optical lens, the maximum angle of view FOV of the optical lens, the curvature radius r13 of the object-side surface S13 of the seventh lens L7, the curvature radius r14 of the image-side surface S14 of the seventh lens L7, and the center thickness D13 of the seventh lens L7.

TABLE 3

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	4.8692	0.9500	1.77	49.61
2	2.8157	1.7512
					3	-100.0000	1.2000	1.49	70.42
4	4.8800	0.3223
					5	6.4697	2.0220	1.85	23.79
6	-100.3803	0.0000
					STO	All-round	1.3998
8	-8.2517	0.6000	1.85	23.79
					9	7.7948	2.5000	1.69	54.57
10	-4.7047	0.1000
					11	21.8831	1.7000	1.49	70.42
12	-14.9007	0.1000
					13	8.5000	2.0000	1.49	70.42
14	17.4796	0.6000
					15	Infinity	0.5500	1.52	64.21
16	Infinity	2.0000
					17	Infinity	0.4000	1.52	64.21
18	Infinity	3.4226
					IMA	Infinity

TABLE 4

TTL(mm)	21.618	FOV(°)	60.000
				F(mm)	5.268	r13(mm)	8.652
BFL(mm)	6.973	d13(mm)	1.500
				D(mm)	7.600	r14(mm)	16.600
h(mm)	5.454

In the present embodiment, TTL/F is 4.103, which is satisfied between the total optical length TTL of the optical lens and the entire focal length F of the optical lens; the BFL/TTL between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens is 0.323; D/h/FOV is 0.023 between the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens and the image height h corresponding to the maximum field angle of the optical lens; r14/(r13-d13) ═ 2.321 is satisfied among the radius of curvature r13 of the object-side surface S13 of the seventh lens L7, the radius of curvature r14 of the image-side surface S14 of the seventh lens L3, and the center thickness d13 of the seventh lens L7; and r13/r14 is 0.521 between the radius of curvature r13 of the object-side surface S13 of the seventh lens L7 and the radius of curvature r14 of the image-side surface S14 of the seventh lens L3.

Example 3

An optical lens according to embodiment 3 of the present application is described below with reference to fig. 3. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 3 shows a schematic structural diagram of an optical lens according to embodiment 3 of the present application.

As shown in fig. 3, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

Table 5 below shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 3, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 6 below gives the total optical length TTL of the optical lens of embodiment 3 (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface S19), the entire group focal length value F of the optical lens, the optical back focus BFL of the optical lens (i.e., the on-axis distance from the center of the image-side surface S14 of the last lens L7 to the imaging surface S19), the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum angle of view of the optical lens, the image height h corresponding to the maximum angle of view of the optical lens, the maximum angle of view FOV of the optical lens, the curvature radius r13 of the object-side surface S13 of the seventh lens L7, the curvature radius r14 of the image-side surface S14 of the seventh lens L7, and the center thickness D13 of the seventh lens L7.

TABLE 5

TABLE 6

TTL(mm)	20.367	FOV(°)	60.000
				F(mm)	5.433	r13(mm)	7.401
BFL(mm)	6.477	d13(mm)	2.000
				D(mm)	7.600	r14(mm)	27.610
h(mm)	5.556

The total optical length TTL of the optical lens and the whole group focal length value F of the optical lens meet the condition that TTL/F is 3.749; the BFL/TTL is 0.318 between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens; D/h/FOV is 0.023 between the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens and the image height h corresponding to the maximum field angle of the optical lens; r14/(r13-d13) ═ 5.112 among the radius of curvature r13 of the object-side surface S13 of the seventh lens L7, the radius of curvature r14 of the image-side surface S14 of the seventh lens L3, and the center thickness d13 of the seventh lens L7; and r13/r14 is 0.268 between the radius of curvature r13 of the object-side surface S13 of the seventh lens L7 and the radius of curvature r14 of the image-side surface S14 of the seventh lens L3.

In summary, examples 1 to 3 each satisfy the relationship shown in table 7 below.

TABLE 7

Conditions/examples	1	2	3
				TTL/F	3.897	4.103	3.749
BFL/TTL	0.352	0.323	0.318
				D/h/FOV	0.019	0.023	0.023
r14/(r13-d13)	2.321	2.321	5.112
				r13/r14	0.521	0.521	0.268

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. An optical lens system, wherein the lens having a refractive power includes only a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, and a seventh lens element, and the first lens element to the seventh lens element are arranged in order from an object side to an image side along an optical axis,

it is characterized in that the preparation method is characterized in that,

the first lens has negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface;

the second lens has negative focal power, and both the object side surface and the image side surface of the second lens are concave;

the third lens has positive focal power, and both the object side surface and the image side surface of the third lens are convex surfaces;

the fourth lens has negative focal power, and both the object side surface and the image side surface of the fourth lens are concave surfaces;

the fifth lens has positive focal power, and both the object side surface and the image side surface of the fifth lens are convex surfaces;

the sixth lens has positive focal power, and both the object side surface and the image side surface of the sixth lens are convex surfaces; and

the seventh lens has positive focal power, the object side surface of the seventh lens is a convex surface, the image side surface of the seventh lens is a concave surface,

the distance TTL from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis and the whole group of focal length values F of the optical lens satisfy the following conditions: TTL/F is less than or equal to 4.2.

2. An optical lens according to claim 1, characterized in that the fourth lens is cemented with the fifth lens.

3. An optical lens according to claim 1, characterized in that a radius of curvature r13 of an object side surface of the seventh lens, a radius of curvature r14 of an image side surface of the seventh lens, and a center thickness d13 of the seventh lens satisfy: r14/(r13-d13) is not less than 1.5 and not more than 6.5.

4. An optical lens as claimed in claim 1, characterized in that a radius of curvature r13 of the object-side surface of the seventh lens and a radius of curvature r14 of the image-side surface of the seventh lens satisfy: r13/r14 is more than or equal to 0.2 and less than or equal to 0.8.

5. An optical lens according to claim 1, further comprising a stop between the third lens and the fourth lens.

6. An optical lens barrel according to any one of claims 1 to 5, wherein a distance TTL on the optical axis from a center of an object side surface of the first lens element to an image plane of the optical lens and a distance BFL on the optical axis from a center of an image side surface of the seventh lens element to the image plane of the optical lens satisfy BFL/TTL ≧ 0.3.

7. An optical lens according to any one of claims 1 to 5, wherein the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens satisfy: D/h/FOV is less than or equal to 0.03.

8. An optical lens system, wherein the lens having a refractive power includes only a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, and a seventh lens element, and the first lens element to the seventh lens element are arranged in order from an object side to an image side along an optical axis,

it is characterized in that the preparation method is characterized in that,

the first lens, the second lens, and the fourth lens have negative optical power;

the third lens, the fifth lens, the sixth lens, and the seventh lens have positive optical power;

the object side surface and the image side surface of the second lens are both concave surfaces;

the fourth lens is glued with the fifth lens; and

the curvature radius r13 of the object side surface of the seventh lens and the curvature radius r14 of the image side surface of the seventh lens satisfy that: r13/r14 is more than or equal to 0.2 and less than or equal to 0.8.

9. An optical lens barrel according to claim 8, wherein the object side surface of the first lens element is convex and the image side surface of the first lens element is concave.

10. An optical lens barrel according to claim 8, wherein the object side surface and the image side surface of the third lens are convex.

11. An optical lens barrel according to claim 8, wherein the fourth lens element has both object and image side surfaces that are concave.

12. An optical lens barrel according to claim 8, wherein the object-side surface and the image-side surface of the fifth lens element are convex.

13. An optical lens barrel according to claim 8, wherein the object-side surface and the image-side surface of the sixth lens element are convex.

14. An optical lens barrel according to claim 8, wherein the seventh lens element has a convex object-side surface and a concave image-side surface.

15. An optical lens barrel according to any one of claims 8 to 14, wherein a radius of curvature r13 of an object side surface of the seventh lens, a radius of curvature r14 of an image side surface of the seventh lens, and a center thickness d13 of the seventh lens satisfy: r14/(r13-d13) is not less than 1.5 and not more than 6.5.

16. An optical lens barrel according to any one of claims 8 to 14, wherein a distance TTL between a center of an object side surface of the first lens element and an image plane of the optical lens on the optical axis, and a distance BFL between a center of an image side surface of the seventh lens element and the image plane of the optical lens on the optical axis, satisfy BFL/TTL ≧ 0.3.

17. An optical lens according to any one of claims 8 to 14, further comprising a diaphragm between the third lens and the fourth lens.

18. An optical lens barrel according to any one of claims 8 to 14, wherein a distance TTL between a center of an object side surface of the first lens and an imaging surface of the optical lens on the optical axis and a full group focal length value F of the optical lens satisfy: TTL/F is less than or equal to 4.2.

19. An optical lens according to any one of claims 8 to 14, wherein the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens satisfy: D/h/FOV is less than or equal to 0.03.