CN109307919B

CN109307919B - Optical lens

Info

Publication number: CN109307919B
Application number: CN201710630357.1A
Authority: CN
Inventors: 郎海涛; 周召涛; 杨佳
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2017-07-28
Filing date: 2017-07-28
Publication date: 2021-04-02
Anticipated expiration: 2037-07-28
Also published as: CN109307919A

Abstract

The application discloses optical lens, this optical lens include by front end to rear end according to the preface along the 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 front end surface of the first lens, the front end surface of the second lens and the rear end surface of the fifth lens are convex surfaces; the rear end surface of the third lens and the front end surface of the fourth lens are both concave surfaces; the front end surface and the rear end surface of the sixth lens are convex surfaces; at least one of the front end surface and the rear end surface of the seventh lens is a convex surface; at least two of the first lens, the second lens and the third lens have positive focal power; at least one of the fourth lens and the fifth lens has a negative power; and the sixth lens and the seventh lens each have positive optical power.

Description

Optical lens

Technical Field

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

Background

With the development of the technology and the wide application of computers, the field of the lens is more and more extensive. In some application fields, the lens is generally required to have good imaging quality, and meanwhile, the lens needs to have small volume, strong stability and the like, and can normally work in a large temperature range. In some fields of special applications (e.g., vehicle-mounted lenses or projection lenses requiring a special long back focus, etc.), the lenses are also required to have a long back focus.

For example, a vehicle-mounted lens is required to be used outdoors, and the performance stability of the lens in different temperature environments is particularly important. Meanwhile, due to the limitation of the installation space in the vehicle, the miniaturization of the lens is also required correspondingly.

Such as a projection lens, a projection device generates a large amount of heat when it works for a long time, and the performance stability of the lens after the temperature changes is a factor that must be considered. Meanwhile, with the development trend of projection devices toward portability and miniaturization, the miniaturization of projection lenses is also an inevitable trend.

Disclosure of Invention

The present application provides an optical lens, such as a tele back optical lens, that may address at least one of the above-mentioned shortcomings of the prior art.

An aspect of the present application provides an optical lens including, in order from a front end to a rear end 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 front end surface of the first lens, the front end surface of the second lens and the rear end surface of the fifth lens can be convex surfaces; the rear end surface of the third lens and the front end surface of the fourth lens can be both concave surfaces; the front end surface and the rear end surface of the sixth lens can be convex surfaces; at least one of the front end surface and the rear end surface of the seventh lens may be convex; at least two of the first lens, the second lens, and the third lens may have positive optical power; at least one of the fourth lens and the fifth lens may have a negative power; and the sixth lens and the seventh lens may each have positive optical power.

In one embodiment, the first lens may have a positive optical power.

In one embodiment, the second lens and the third lens may be cemented to form a first cemented lens.

In one embodiment, the fourth lens and the fifth lens may be cemented to form a second cemented lens.

In one embodiment, the second lens in the first cemented lens may have a positive optical power; the third lens in the first cemented lens may have a negative optical power.

In one embodiment, the rear end surface of the second lens in the first cemented lens may be a concave surface; the front end surface of the third lens in the first cemented lens may be convex.

In one embodiment, the fourth lens in the second cemented lens may have a negative optical power; the fifth lens of the second cemented lens may have a positive optical power.

In one embodiment, the rear end surface of the fourth lens in the second cemented lens may be a concave surface; the front end surface of the fifth lens in the second cemented lens may be convex.

In one embodiment, a curvature radius R10 of the front end surface of the sixth lens and a curvature radius R11 of the rear end surface of the sixth lens may satisfy | R10| ═ R11 |.

In one embodiment, the total optical length TTL of the optical lens and the whole group focal length f of the optical lens can satisfy TTL/f ≦ 5.

In one embodiment, the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens can satisfy BFL/TTL more than or equal to 0.2.

Another aspect of the present application also provides an optical lens, sequentially including, from a front end to a rear end along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and at least one subsequent lens. The first lens can have positive focal power, and the front end surface of the first lens can be a convex surface; the second lens and the fifth lens both have positive focal power, and the front end surface of the second lens and the rear end surface of the fifth lens both can be convex surfaces; the third lens and the fourth lens both have negative focal power, and the rear end surface of the third lens and the front end surface of the fourth lens both can be concave surfaces; and the combined power of at least one subsequent lens is a positive power. The second lens and the third lens can be glued to form a first glued lens, and the fourth lens and the fifth lens can be glued to form a second glued lens.

In one embodiment, the optical lens further includes a stop disposed between the third lens and the fourth lens.

In one embodiment, the at least one subsequent lens comprises, in order from the fifth lens to the rear end along the optical axis: and a sixth lens and a seventh lens, wherein at least one of the sixth lens and the seventh lens may have positive optical power.

In one embodiment, the sixth lens and the seventh lens may each have positive optical power.

In one embodiment, both the front and rear end faces of the sixth lens may be convex.

In one embodiment, the front end surface of the seventh lens may be convex.

The application adopts a plurality of lenses (for example, seven lenses), and the optical lens has at least one of the following beneficial effects by reasonably distributing the focal power, the surface type, the on-axis distance of each lens and the like:

the back focal length;

the volume is small, the size is small, and the installation is convenient;

the device can adapt to a large range of environmental temperature;

minor chromatic aberration and distortion; and

higher resolution and higher imaging quality.

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;

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

fig. 4 is a schematic view showing a structure of an optical lens according to embodiment 4 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. In this document, the surface closest to the front end in each lens is referred to as the front end surface, and the surface closest to the rear end in each lens is referred to as the rear end 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 front end to the rear end along the optical axis.

The first lens may have a positive optical power; the second lens may have a positive optical power; the third lens may have a negative optical power; the fourth lens may have a negative optical power; the fifth lens may have a positive optical power; the sixth lens may have a positive optical power; and the seventh lens may have a positive optical power.

The optical lens in the application can be applied to various lenses with long back focus requirements, for example, the optical lens in the application can be applied to camera lenses such as vehicle-mounted lenses, and the like, and also can be applied to projection lenses. When the optical lens of the present application is applied to an imaging lens, such as a vehicle-mounted lens, the front end is an object side of the lens, and the rear end is an image side of the lens. When the optical lens of the present application is applied to a projection lens, the front end is an enlargement end of the lens, and the rear end is a reduction end of the lens.

The front end surface of the first lens may be convex. When the optical lens of the present application is used as, for example, an in-vehicle lens, the convex arrangement of the front end surface of the first lens is advantageous in collecting as much light as possible into the rear optical system. When the optical lens of the present application is used as, for example, a projection lens, the convex arrangement of the first lens is advantageous in ensuring as large a projection angle as possible. Alternatively, the rear end surface of the first lens may be concave. When the first lens is arranged as a meniscus lens with the convex surface facing the front end and used in a projection lens, the meniscus shape with the convex surface of the first lens facing the magnification end can ensure as large a projection angle as possible.

The front end surface of the second lens can be a convex surface, and the rear end surface can be a concave surface. The front end surface of the third lens can be a convex surface, and the rear end surface can be a concave surface. Alternatively, the first cemented lens composed of the second lens and the third lens may be formed by cementing the rear end face of the second lens with the front end face of the third lens. The first cemented lens can correct chromatic aberration by itself, and can also compensate residual chromatic aberration and axial point monochromatic aberration. The first cemented lens may be arranged at a position close to the diaphragm in consideration of the balance of its system aberrations and the rationality of the structure.

In an exemplary embodiment, a diaphragm for limiting the light beam may be disposed between, for example, the third lens and the fourth lens to further improve the imaging quality of the lens. The diaphragm is arranged between the third lens and the fourth lens, and is used for collecting front and rear light rays, so that the total length of the optical system is favorably shortened, and the calibers of the front and rear lens groups are reduced.

The front end surface of the fourth lens can be a concave surface, and the rear end surface can be a concave surface. The front end surface of the fifth lens can be a convex surface, and the rear end surface can be a convex surface. The rear end surface of the fourth lens may be cemented with the front end surface of the fifth lens, thereby forming a second cemented lens that is a combination of the fourth lens and the fifth lens. The second cemented lens can eliminate chromatic aberration by itself, and can also retain partial chromatic aberration to balance the overall chromatic aberration of the optical system.

When the stop is disposed between the third lens and the fourth lens, the second cemented lens composed of the fourth lens and the fifth lens and the first cemented lens composed of the second lens and the third lens have substantially symmetry with respect to the stop. Specifically, the second lens and the fifth lens have positive optical power, and the third lens and the fourth lens have negative optical power, so that the power distribution of the four lenses is approximately symmetrical about the diaphragm; and the front end surface of the second lens is a convex surface, the rear end surface of the third lens is a concave surface, the front end surface of the fourth lens is a concave surface, and the rear end surface of the fifth lens is a convex surface, so that the structural shapes of the first cemented lens formed by the second lens and the third lens and the second cemented lens formed by the fourth lens and the fifth lens are approximately symmetrical about the diaphragm. The symmetrical design can reduce the drift of the back focal length of the lens along with the change of the environmental temperature and can further balance the chromatic aberration and the aberration of the system.

The front end surface of the sixth lens can be a convex surface, and the rear end surface can be a convex surface. Alternatively, the front end surface and the rear end surface of the sixth lens may have the same curvature, that is, a curvature radius R10 of the front end surface of the sixth lens and a curvature radius R11 of the rear end surface of the sixth lens may satisfy | R10| ═ R11|, to effectively reduce the amount of distortion. Optionally, the sixth lens can be a high refractive index or high abbe number lens to compensate for chromatic aberration of the system.

The front end surface of the seventh lens may be convex. The seventh lens is a converging lens for adjusting the light rays so that the trend of the light rays is in stable transition. Alternatively, the seventh lens may be a low refractive index lens. Alternatively, the rear end surface of the seventh lens may be concave such that the seventh lens has a meniscus shape with a convex surface facing the front end, thereby facilitating the increase of the back focus of the lens.

The total optical length TTL of the optical lens and the whole group focal length f of the optical lens can meet the condition that TTL/f is less than or equal to 5, and more specifically, TTL and f can further meet the condition that TTL/f is less than or equal to 3.04 and less than or equal to 4.46. The condition formula TTL/f is less than or equal to 5, and the miniaturization characteristic of the lens can be embodied. Note that, when the optical lens of the present application is used as, for example, an in-vehicle lens, the total optical length TTL of the lens refers to an on-axis distance from the center of the front end surface of the first lens to the lens imaging surface; when the optical lens of the present application is used as, for example, a projection lens, the total optical length TTL of the lens refers to an on-axis distance from the center of the front end face of the first lens to the surface of the spatial light modulator for modulating the projection signal.

The optical back focus BFL of the optical lens and the optical total length TTL of the optical lens can meet the condition that BFL/TTL is more than or equal to 0.2, and more particularly, the BFL and the TTL can further meet the condition that BFL/TTL is more than or equal to 0.22 and less than or equal to 0.30. The condition that BFL/TTL is more than or equal to 0.2 is met, the optical lens has longer back focus, and the assembly of an effective space can be realized, so that the optical lens can be suitable for various applications with long back focus requirements. The longer back focus can reserve space for optical element installation and focusing, and can avoid mechanism interference simultaneously. When the optical lens of the present application is used as an imaging lens such as an in-vehicle lens, the optical back focus BFL of the lens refers to an on-axis distance from the rear end surface of the seventh lens to the lens imaging surface; when the optical lens of the present application is used as a projection lens, the optical back focus BFL of the lens refers to an on-axis distance from the rear end surface of the seventh lens to the surface of the spatial light modulator for modulating the projection signal.

The optical lens according to the above-described embodiment of the present application may employ a plurality of lenses, for example, seven lenses as described above. Through reasonable lens shape setting, lens arrangement, distribution of focal power and reasonable collocation of each lens, can make the camera lens have better stability (promptly, can keep better imaging effect in the ambient temperature scope of difference), can also make the camera lens have shorter optics total length and longer back focal length when guaranteeing imaging quality simultaneously. The shorter total optical length is beneficial to realizing the miniaturization of the lens, so that the lens can be installed in a limited space. The longer back focal length enables the optical lens to be suitable for applications with special requirements on the back focal length, such as an on-vehicle lens or a projection lens with special long back focal length. In addition, the optical lens has longer back focal length, so that the optical lens has better compatibility when being used as a projection lens and matched with an illumination system, and has wider applicability.

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 sequentially includes, from front to back along an 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 convex-flat lens with positive refractive power, and has a convex front end surface S1 and a flat rear end surface S2.

The second lens L2 is a meniscus lens with positive refractive power, and its front end surface S3 is convex and its rear end surface S4 is concave. The third lens L3 is a meniscus lens having a negative refractive power, and has a convex front end surface S4 and a concave rear end surface S5. Wherein, the rear end surface S4 of the second lens L2 and the front end surface S4 of the third lens L3 are cemented to form the first cemented lens.

The fourth lens L4 is a biconcave lens with negative refractive power, and its front end surface S7 is concave and its rear end surface S8 is concave. The fifth lens L5 is a biconvex lens with positive refractive power, and has a convex front end surface S8 and a convex rear end surface S9. Wherein, the rear end surface S8 of the fourth lens L4 and the front end surface S8 of the fifth lens L5 are cemented to form a second cemented lens.

The sixth lens L6 is a biconvex lens with positive refractive power, and has a convex front end surface S10 and a convex rear end surface S11.

The seventh lens L7 is a biconvex lens with positive refractive power, and has a convex front end surface S12 and a convex rear end surface S13.

Alternatively, a stop STO may be disposed between the third lens L3 and the fourth lens L4 to improve the imaging quality of the optical lens.

When the optical lens is applied to an image pickup lens such as a vehicle-mounted lens, the front end is an object side of the lens, and the rear end is an image side of the lens. S14 is an image plane, and light from the object side passes through the surfaces S1 to S13 in sequence and is finally imaged on the image plane S14. Optionally, the optical lens may further include a filter for correcting color deviation and/or a protective glass for protecting the photosensitive element located on the imaging surface S14.

When the optical lens is applied to a projection lens, the front end is an amplifying end of the lens, and the rear end is a reducing end of the lens. S14 is a surface (SLM surface) of a spatial light modulator for modulating a projection signal, and light from the SLM surface S14 passes through the respective surfaces S13 to S1 in sequence and finally imaged on a screen (not shown). Alternatively, the optical lens may also include other well-known optical projection elements, such as prisms, field lenses, and the like.

Table 1 shows a curvature radius 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 units of the curvature radius R and the thickness T are both (mm).

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					S1	34.5341	2.1024	1.85	23.80
S2	All-round	0.8064
					S3	25.0000	2.9618	1.77	49.60
S4	62.3511	4.0522	1.53	48.80
					S5	4.1030	5.1501
STO	All-round	1.9317
					S7	-90.9506	4.2245	1.85	23.80
S8	16.8474	4.6486	1.50	81.60
					S9	-8.1298	0.1841
S10	48.1690	2.9587	1.80	46.60
					S11	-48.1690	2.0974
S12	43.1740	2.8891	1.77	49.60
					S13	-43.1740	12.4762
S14	All-round

TABLE 1

As can be seen from table 1, the radius of curvature R10 of the front end surface S10 of the sixth lens L6 and the radius of curvature R11 of the rear end surface S11 of the sixth lens L6 satisfy | R10| ═ R11| ═ 48.1690 mm.

The entire group focal length f of the optical lens, the optical back focus BFL of the optical lens, and the total optical length TTL of the optical lens in example 1 are given in table 2 below.

Wherein, when the optical lens is used as an imaging lens such as an in-vehicle lens, the optical back focus BFL of the lens refers to an on-axis distance from the center of the rear end surface S13 of the seventh lens L7 to the imaging surface S14; the total optical length TTL of the lens barrel refers to an on-axis distance from the center of the front end surface S1 of the first lens L1 to the image plane S14. When the optical lens is used as a projection lens, the optical back focus BFL of the lens refers to an on-axis distance from the center of the rear end face S13 of the seventh lens L7 to the SLM surface S14; the total optical length TTL of the lens refers to an on-axis distance from the center of the front end face S1 of the first lens L1 to the SLM surface S14.

Parameter(s)	f(mm)	BFL(mm)	TTL(mm)
				Numerical value	10.41	12.48	46.48

TABLE 2

According to table 2, the total optical length TTL of the optical lens and the entire focal length f of the optical lens satisfy TTL/f of 4.46; the BFL/TTL between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens is 0.27.

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 sequentially includes, from the front end to the rear end 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 biconvex lens with positive refractive power, and has a convex front end surface S1 and a convex rear end surface S2.

Table 3 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 (mm). Table 4 shows the entire group focal length f of the optical lens, the optical back focus BFL of the optical lens, and the total optical length TTL of the optical lens in example 2.

TABLE 3

Parameter(s)	f(mm)	BFL(mm)	TTL(mm)
				Numerical value	15.06	14.35	48.38

TABLE 4

Example 3

An optical lens according to embodiment 3 of the present application is described below with reference to fig. 3. 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 sequentially includes, from the front end to the rear end 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 positive refractive power, and its front end surface S1 is convex and its rear end surface S2 is concave.

Table 5 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 (mm). Table 6 shows the entire group focal length f of the optical lens, the optical back focus BFL of the optical lens, and the total optical length TTL of the optical lens in example 3.

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					S1	61.9480	3.0000	1.85	23.80
S2	115.7490	11.0000
					S3	7.7000	2.1288	1.77	49.60
S4	12.9176	1.9662	1.53	48.80
					S5	4.2917	7.0420
STO	All-round	0.2430
					S7	-9.3252	4.0270	1.85	23.80
S8	63.1439	4.5355	1.77	49.60
					S9	-11.1685	1.5999
S10	38.8917	2.9148	1.50	81.60
					S11	-38.8917	4.0000
S12	18.0711	2.1605	1.74	49.20
					S13	-600.0000	12.7425
S14	All-round

TABLE 5

Parameter(s)	f(mm)	BFL(mm)	TTL(mm)
				Numerical value	15.39	12.74	57.36

TABLE 6

Example 4

An optical lens according to embodiment 4 of the present application is described below with reference to fig. 4. Fig. 4 shows a schematic structural diagram of an optical lens according to embodiment 4 of the present application.

As shown in fig. 4, the optical lens sequentially includes, from the front end to the rear end 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 seventh lens L7 is a meniscus lens having positive refractive power, and its front end surface S12 is convex and its rear end surface S13 is concave.

Table 7 shows the radius of curvature R, the thickness T, the refractive index Nd, and the abbe number Vd of each lens of the optical lens of example 4, where the radius of curvature R and the thickness T are both in units of (mm). Table 8 shows the entire group focal length f of the optical lens, the optical back focus BFL of the optical lens, and the total optical length TTL of the optical lens in example 4.

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					S1	35.4498	1.5780	1.85	23.80
S2	72.0000	6.1992
					S3	11.0000	2.2752	1.77	49.60
S4	19.1922	1.9662	1.53	48.80
					S5	6.2532	3.7422
STO	All-round	2.8413
					S7	-9.2604	4.0270	1.85	23.80
S8	64.9050	4.5350	1.77	49.60
					S9	-11.9784	1.5990
S10	29.2630	4.4000	1.50	81.60
					S11	-29.2630	2.9990
S12	16.0213	2.1605	1.74	49.20
					S13	36.4908	14.2348
S14	All-round

TABLE 7

Parameter(s)	f(mm)	BFL(mm)	TTL(mm)
				Numerical value	17.31	14.23	52.56

TABLE 8

In summary, examples 1 to 4 each satisfy the relationship shown in table 9 below.

Conditional expression (A) example	1	2	3	4
					TTL/f	4.46	3.21	3.73	3.04
BFL/TTL	0.27	0.30	0.22	0.27

TABLE 9

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 in which the number of lenses having optical power is seven, which are: 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, the first lens element through the seventh lens element being arranged in order from a front end to a rear end along an optical axis,

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

the front end surface of the first lens, the front end surface of the second lens and the rear end surface of the fifth lens are convex surfaces;

the rear end face of the third lens and the front end face of the fourth lens are both concave surfaces;

the front end surface and the rear end surface of the sixth lens are convex surfaces;

at least one of the front end surface and the rear end surface of the seventh lens is a convex surface;

at least two of the first lens, the second lens, and the third lens have positive optical power;

at least one of the fourth lens and the fifth lens has a negative optical power; and

the sixth lens and the seventh lens each have positive optical power;

wherein the second lens and the third lens are cemented to form a first cemented lens;

and the fourth lens and the fifth lens are cemented to form a second cemented lens.

2. An optical lens as claimed in claim 1, characterized in that the first lens has a positive optical power.

3. An optical lens according to claim 1, characterized in that the second lens of the first cemented lens has positive optical power; and

the third lens in the first cemented lens has a negative optical power.

4. An optical lens according to claim 3, wherein the rear end surface of the second lens in the first cemented lens is a concave surface; and

the front end surface of the third lens in the first cemented lens is a convex surface.

5. An optical lens according to claim 1, characterized in that the fourth lens in the second cemented lens has a negative optical power; and

the fifth lens of the second cemented lens has positive optical power.

6. An optical lens according to claim 5, wherein the rear end surface of the fourth lens in the second cemented lens is a concave surface; and

the front end surface of the fifth lens in the second cemented lens is a convex surface.

7. An optical lens according to any one of claims 1 to 6, wherein a radius of curvature R10 of the sixth lens front end surface and a radius of curvature R11 of the sixth lens rear end surface satisfy | R10| ═ R11 |.

8. An optical lens according to any one of claims 1 to 6, wherein the total optical length TTL of the optical lens and the entire group focal length f of the optical lens satisfy TTL/f ≦ 5.

9. An optical lens according to any one of claims 1 to 6, wherein a BFL/TTL ratio between an optical back focus BFL of the optical lens and an optical total length TTL of the optical lens is equal to or greater than 0.2.