CN110412725B

CN110412725B - Optical lens

Info

Publication number: CN110412725B
Application number: CN201810401656.2A
Authority: CN
Inventors: 王东方; 孙毅; 李响; 姚波
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2018-04-28
Filing date: 2018-04-28
Publication date: 2021-11-30
Anticipated expiration: 2038-04-28
Also published as: CN110412725A

Abstract

The present application discloses an optical lens, sequentially from an object side to an image side along an optical axis, comprising: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens has negative focal power, and the object side surface and the image side surface of the first lens are both concave surfaces; the second lens has positive focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; 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 and the fifth lens are glued to form a cemented lens; and the sixth lens has a positive optical power.

Description

Optical lens

Technical Field

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

Background

In recent years, the vehicle-mounted lens is widely applied to a vehicle-mounted driving assistance system for assisting a driver in driving, even for automatic driving, and becomes an indispensable device for ensuring the driving safety of a vehicle. With the annual increase of the usage of the lens in the market, enterprises which are rushing into the industry are also increasing, the industry competition is intensified, and it becomes more important to reduce the lens cost and improve the competitiveness.

In general, the use of plastic lenses is a straightforward way to reduce costs. However, due to the special application environment of the vehicular lens, the lens is required to maintain better resolution on hot and high-temperature days and cold rainy and snowy days. In particular to an active safety vehicle-mounted front-view lens, which has higher requirements on the stability of the lens and needs to strictly control the influence of temperature on the imaging of the lens, namely strictly control the back focus offset of the lens.

However, the lens having the plastic lens has poor high and low temperature imaging performance due to poor thermal stability of the optical plastic, thereby limiting the cost and weight of the in-vehicle front view lens and the automatic driving lens.

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.

In one aspect, the present application provides an optical lens, in order from an object side to an image side along an optical axis, comprising: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens can have negative focal power, and both the object side surface and the image side surface of the first lens can be concave; the second lens can have positive focal power, and the object side surface of the second lens can be a convex surface, and the image side surface of the second lens can be a concave surface; the third lens can have positive focal power, and both the object side surface and the image side surface of the third lens can be convex surfaces; the fourth lens and the fifth lens can be glued to form a cemented lens; and the sixth lens may have a positive optical power.

In one embodiment, the fourth lens of the cemented lens may have positive optical power, and both the object-side surface and the image-side surface thereof may be convex; and a fifth lens of the cemented lenses may have a negative optical power, and both the object-side surface and the image-side surface thereof may be concave.

In one embodiment, both the object-side surface and the image-side surface of the sixth lens element may be convex at the paraxial region.

In one embodiment, the first to sixth lenses may include two aspherical lenses.

In one embodiment, the second lens and the sixth lens may be plastic aspherical lenses.

In one embodiment, an object-side surface of the sixth lens element may be concave at the distal axis and an image-side surface of the sixth lens element may be convex at the distal axis.

In one embodiment, the effective focal length f2 of the second lens and the total effective focal length f of the optical lens can satisfy 14 ≦ f2/f ≦ 24.

In one embodiment, the effective focal length f6 of the sixth lens and the total effective focal length f of the optical lens can satisfy 1.8 ≦ f6/f ≦ 2.4.

In one embodiment, the total optical length TTL of the optical lens and the total effective focal length f of the optical lens satisfy TTL/f ≦ 3.8.

In another aspect, the present application provides an optical lens, in order from an object side to an image side along an optical axis, comprising: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens can have negative focal power, and both the object side surface and the image side surface of the first lens can be concave; the second lens can have positive focal power, and the object side surface of the second lens can be a convex surface, and the image side surface of the second lens can be a concave surface; the third lens can have positive focal power, and both the object side surface and the image side surface of the third lens can be convex surfaces; the fourth lens can have positive focal power, and both the object side surface and the image side surface of the fourth lens can be convex surfaces; the fifth lens can have negative focal power, and both the object side surface and the image side surface of the fifth lens can be concave; the sixth lens may have a positive optical power. Wherein, the total optical length TTL of the optical lens and the total effective focal length f of the optical lens can satisfy TTL/f less than or equal to 3.8.

In one embodiment, the first to sixth lenses may include two aspherical lenses.

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

The optical lens adopts six lenses, optimizes the lens material selection, reasonably adopts the aspheric lens, reasonably distributes the focal power of the lens and the like, and has at least one beneficial effect of low cost, miniaturization, high resolution, good thermal compensation and the like.

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; and

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 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 closer to the object side in each lens is referred to as the object side surface of the lens, and the surface closer to the image side in each lens is referred to as the image side surface of the lens.

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, six lenses having optical power, i.e., a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The six lenses are arranged in order from the object side to the image side along the optical axis.

The first lens element can have a negative optical power, and both the object-side surface and the image-side surface can be concave. The first lens can have negative focal power and low refractive index so as to avoid overlarge divergence of object light rays and be beneficial to aperture control of the rear lens. The first lens may also have a higher abbe number to facilitate reducing chromatic aberrations of the system as a whole. The first lens is reasonably arranged, so that the caliber of the front end of the lens is reduced, and the whole volume of the lens is reduced; meanwhile, the method is favorable for moderately increasing distortion so as to be suitable for the situations of a vehicle event data recorder and the like which need to intensively observe the front small-range condition picture.

The second lens element can have a positive power, and can have a convex object-side surface and a concave image-side surface. Optionally, the second lens can be a lens made of plastic material, so as to reduce the cost and weight of the lens. Because the second lens is a convergent lens, the off-axis optical trend is relatively stable by utilizing the meniscus shape of the second lens, and the optical transition is further stable to the rear. Alternatively, the second lens may be an aspheric lens, and the aspheric surface of the second lens may provide some correction for the off-axis point aberration.

The third lens element can have a positive power, and can have a convex object-side surface and a convex image-side surface. The third lens is a converging lens and may have a high refractive index and a low abbe number to compensate for on-axis aberrations produced by the first and second lenses. The third lens can compress light rays so that the light rays can be stably emitted into the diaphragm, the aperture of the diaphragm can be increased, and the light flux of the system can be increased. Meanwhile, the third lens with high refractive index has better light converging effect, and is beneficial to reducing the size of the lens.

In an exemplary embodiment, the optical lens may further include a diaphragm for limiting the light beam to further improve the imaging quality of the lens. Optionally, a diaphragm may be disposed between the third lens and the fourth lens to facilitate effective beam-converging of light entering the optical system, and reduce the aperture of the lens of the optical system. It should be understood that the diaphragm position is not limited thereto, and the diaphragm may be disposed at any other position as needed.

The fourth lens element can have a positive power, and can have a convex object-side surface and a convex image-side surface. The fifth lens element can have a negative optical power, and can have a concave object-side surface and a concave image-side surface. The fourth lens and the fifth lens are a pair of mutually sensitive lenses, and the image side surface of the fourth lens is cemented with the object side surface of the fifth lens to form a cemented lens, so that the sensitivity of the lens is reduced, and the production possibility is improved. Double gluing can compensate residual chromatic aberration and on-axis point monochromatic aberration while correcting chromatic aberration by itself. The cemented lens is placed close to the stop in consideration of the balance of system aberrations and the rationality of the structure.

To further reduce the f-number Fno and increase the aperture of the system, a lens with positive power is needed behind the cemented lens to converge the light. The sixth lens element can have a positive optical power, and can have a convex object-side surface and a convex image-side surface. Optionally, the sixth lens element may be a plastic lens element to reduce the cost and weight of the lens assembly. Alternatively, the sixth lens element may be an aspheric lens element having a concave object-side surface at the distal axis and a convex image-side surface at the distal axis. The sixth lens is an aspheric lens and can well compensate for off-axis point aberration.

The two plastic lenses are main factors influencing the change of the back focus at different temperatures and influence the temperature performance of the lens. Therefore, the focal point assignment limits the power of the two plastic lenses (i.e., the second lens and the sixth lens) and matches the power of the other glass lenses, so that the temperature performance of the entire optical system is improved.

In an exemplary embodiment, 14 ≦ f2/f ≦ 24 may be satisfied between the effective focal length f2 of the second lens and the total effective focal length f of the optical lens, and more specifically, f2 and f may further satisfy 17 ≦ f2/f ≦ 20, e.g., 18.92 ≦ f2/f ≦ 18.99.

In an exemplary embodiment, 1.8 ≦ f6/f ≦ 2.4 between the effective focal length f6 of the sixth lens and the total effective focal length f of the optical lens, and more specifically, f6 and f may further satisfy 1.9 ≦ f6/f ≦ 2.2, for example, 2.04 ≦ f6/f ≦ 2.05.

In an exemplary embodiment, a total optical length TTL of the optical lens (i.e., a distance on an optical axis from a center of an object side surface of the first lens to an imaging surface of the optical lens) and a total effective focal length f of the optical lens may satisfy TTL/f ≦ 3.8, and more specifically, TTL and f may further satisfy TTL/f ≦ 3.5, for example, 3.24 ≦ TTL/f ≦ 3.26. The TTL/f is less than or equal to 3.8, the total length of the optical path of the system is short, and the miniaturization characteristic of the lens can be reflected.

Optionally, the optical lens may further include a filter for correcting color deviation and/or a protective glass for protecting a photosensitive element located on an image plane.

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).

According to the optical lens of the embodiment of the application, through reasonable lens shape design and material collocation, the beneficial effects of low cost, miniaturization, high resolution, good thermal compensation and the like can be realized. The lens configured in the above way can also have the performances of compact structure, light weight, good shock resistance and poor heat dissipation, so that the lens can better meet the vehicle-mounted requirements.

The method and the device can realize the plasticizing in the vehicle-mounted front-view lens to a greater degree, and solve the problem that the vehicle-mounted front-view lens cannot use a plastic lens to reduce the cost and improve the imaging quality for a long time. The optical lens according to the exemplary embodiment of the present application may include two plastic lenses (e.g., a second lens and a sixth lens), and the focal power of the plastic lens is reasonably distributed by reasonably arranging the shapes of the plastic lenses, so that the plastic lens may be reasonably matched with the focal power of other lenses, thereby improving the problem that the resolution is greatly affected by temperature when the plastic lens is used, so that the lens has good temperature performance, and the cost and weight of the lens are reduced. The optical lens can have optical performances of high pixel, large aperture, high light passing and the like, can effectively correct various aberrations of an optical system, and ensures that the optical lens has better imaging definition within the temperature range of-40 ℃ to +85 ℃.

It should be appreciated that although the plasticizing scheme of the present application achieves better temperature stability through reasonable distribution of optical power, in applications where temperature performance is less demanding (e.g., indoor applications), high resolution can be achieved through only the lens shape, power setting in the present application, without focusing on the distribution of optical power.

The optical lens of the present application may have two aspherical lenses (e.g., a second lens and a sixth lens). The plastic aspheric lens is adopted for reasonable focal power distribution, so that the cost is reduced, and the lens has better temperature performance. However, glass aspheric lenses may also be used to further improve the resolution and temperature performance of the lens without regard to cost and weight requirements.

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 six lenses are exemplified in the embodiment, the optical lens is not limited to including six 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 an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5 and a sixth lens element L6.

The first lens L1 is a biconcave lens with negative power, and has concave object-side surface S1 and concave image-side surface S2, and spherical object-side surface S1 and spherical image-side surface S2 of the first lens L1.

The second lens L2 is a meniscus lens with positive power, the object-side surface S3 is convex, the image-side surface S4 is concave, and both the object-side surface S3 and the image-side surface S4 of the second lens L2 are aspheric.

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

The fourth lens L4 is a biconvex lens with positive optical power, and has a convex object-side surface S8 and a convex image-side surface S9, and a spherical object-side surface S8 and a spherical image-side surface S9 of the fourth lens L4.

The fifth lens L5 is a biconcave lens with negative power, and has both object-side surface S9 and image-side surface S10 being concave, and both object-side surface S9 and image-side surface S10 of the fifth lens L5 being spherical.

The sixth lens L6 is a biconvex lens with positive optical power, and has a convex object-side surface S11 and a convex image-side surface S12, and an aspheric object-side surface S11 and an aspheric image-side surface S12 of the sixth lens L6. More specifically, the object-side surface S11 of the sixth lens L6 is convex at the paraxial region and concave at the paraxial region; the image-side surface S12 of the sixth lens is convex at both the paraxial and the paraxial regions.

In the present embodiment, the image-side surface S9 of the fourth lens L4 and the object-side surface S9 of the fifth lens L5 are cemented to form a cemented lens.

Optionally, the optical lens of the present embodiment may further include a filter L7 having an object-side surface S13 and an image-side surface S14, and/or a protective glass L8 having an object-side surface S15 and an image-side surface S16. The light from the object sequentially passes through the respective surfaces S1 to S16 and is finally imaged on the imaging surface S17.

Table 1 shows the radius of curvature R, thickness T, refractive index Nd, and abbe number Vd of each lens of the optical lens of example 1.

TABLE 1

In the present embodiment, the second lens L2 and the sixth lens L6 are aspheric lenses, and each aspheric surface type Z can be defined by, but is not limited to, the following aspheric surface formula:

wherein Z is the distance rise from the vertex of the aspheric surface when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is the conic coefficient conc; A. b, C, D, E are all high order term coefficients. Table 2 below shows the conic coefficients k and the respective high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S11 and S12 in example 1.

Flour mark

k

A

B

C

D

E

S3

1.4002

-3.5335E-03

-1.9634E-04

-1.2024E-06

-5.3291E-08

-4.7342E-09

S4

-1.1624

-2.5472E-03

-4.9429E-05

9.8201E-07

1.2266E-07

-3.0946E-09

S11

-4.8839

-3.2248E-03

-1.1698E-04

-6.1158E-05

7.0052E-06

-7.4113E-07

S12

-9.0992

-2.1081E-03

-2.1313E-04

-2.5996E-05

2.1621E-06

-1.1623E-07

TABLE 2

Table 3 below gives the effective focal length f2 of the second lens L2, the effective focal length f6 of the sixth lens L6, the total effective focal length f of the optical lens, and the total optical length TTL of the optical lens (i.e., the distance on the optical axis from the center of the object-side surface S1 of the first lens L1 to the image plane S17) in embodiment 1.

Parameter(s)	f2(mm)	f6(mm)	f(mm)	TTL(mm)
					Numerical value	116.232	12.503	6.124	19.890

TABLE 3

In the present embodiment, f2/f 18.981 is satisfied between the effective focal length f2 of the second lens L2 and the total effective focal length f of the optical lens; f6/f is 2.042 between the effective focal length f6 of the sixth lens L6 and the total effective focal length f of the optical lens; the total optical length TTL of the optical lens and the total effective focal length f of the optical lens satisfy that TTL/f is 3.248.

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 an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5 and a sixth lens element L6.

Table 4 shows the radius of curvature R, thickness T, refractive index Nd, and abbe number Vd of each lens of the optical lens of example 2.

TABLE 4

Table 5 below shows the conic coefficients k and the respective high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S11 and S12 in example 2, wherein the respective aspherical surface types can be defined by the formula (1) given in example 1 above.

TABLE 5

Table 6 below gives the effective focal length f2 of the second lens L2, the effective focal length f6 of the sixth lens L6, the total effective focal length f of the optical lens, and the total optical length TTL of the optical lens in embodiment 2.

Parameter(s)	f2(mm)	f6(mm)	f(mm)	TTL(mm)
					Numerical value	116.000	12.500	6.125	19.890

TABLE 6

In the present embodiment, f2/f 18.940 is satisfied between the effective focal length f2 of the second lens L2 and the total effective focal length f of the optical lens; f6/f is 2.041 between the effective focal length f6 of the sixth lens L6 and the total effective focal length f of the optical lens; the total optical length TTL of the optical lens and the total effective focal length f of the optical lens satisfy that TTL/f is 3.248.

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 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5 and a sixth lens element L6.

Table 7 shows the radius of curvature R, thickness T, refractive index Nd, and abbe number Vd of each lens of the optical lens of example 3.

TABLE 7

Table 8 below shows the conic coefficients k and the respective high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S11 and S12 in example 3, wherein the respective aspherical surface types can be defined by the formula (1) given in example 1 above.

Flour mark

k

A

B

C

D

E

3

1.3228

-2.2708E-03

-1.6689E-04

4.4727E-06

-4.7843E-07

1.4901E-08

4

0.1949

-1.7391E-03

-4.3643E-05

2.1112E-06

-6.8591E-08

2.6586E-09

11

6.5644

-2.1698E-03

-2.6681E-05

-5.5334E-05

6.4237E-06

-4.7320E-07

12

-26.5336

-2.7198E-03

1.7571E-04

-2.7868E-05

1.5427E-06

-7.0056E-08

TABLE 8

Table 9 below gives the effective focal length f2 of the second lens L2, the effective focal length f6 of the sixth lens L6, the total effective focal length f of the optical lens, and the total optical length TTL of the optical lens in embodiment 3.

Parameter(s)	f2(mm)	f6(mm)	f(mm)	TTL(mm)
					Numerical value	116.000	12.500	6.116	19.890

TABLE 9

In the present embodiment, f2/f 18.965 is satisfied between the effective focal length f2 of the second lens L2 and the total effective focal length f of the optical lens; f6/f is 2.044 between the effective focal length f6 of the sixth lens L6 and the total effective focal length f of the optical lens; the total optical length TTL of the optical lens and the total effective focal length f of the optical lens satisfy that TTL/f is 3.252.

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 includes, in order from an object side to an image side along an optical axis, a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4, a fifth lens element L5 and a sixth lens element L6.

Table 10 shows the radius of curvature R, thickness T, refractive index Nd, and abbe number Vd of each lens of the optical lens of example 4.

Watch 10

Table 11 below shows the conic coefficients k and the respective high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S11 and S12 in example 4, wherein the respective aspherical surface types can be defined by the formula (1) given in example 1 above.

Flour mark

k

A

B

C

D

E

S3

1.4002

-3.5335E-03

-1.9634E-04

-1.2024E-06

-5.3291E-08

-4.7342E-09

S4

-1.1624

-2.5472E-03

-4.9429E-05

9.8201E-07

1.2266E-07

-3.0946E-09

S11

-4.8839

-3.2248E-03

-1.1698E-04

-6.1158E-05

7.0052E-06

-7.4113E-07

S12

-9.0992

-2.1081E-03

-2.1313E-04

-2.5996E-05

2.1621E-06

-1.1623E-07

TABLE 11

Table 12 below gives the effective focal length f2 of the second lens L2, the effective focal length f6 of the sixth lens L6, the total effective focal length f of the optical lens, and the total optical length TTL of the optical lens in embodiment 4.

Parameter(s)	f2(mm)	f6(mm)	f(mm)	TTL(mm)
					Numerical value	116.002	12.503	6.130	19.890

TABLE 12

In the present embodiment, f2/f 18.925 is satisfied between the effective focal length f2 of the second lens L2 and the total effective focal length f of the optical lens; f6/f is 2.040 between the effective focal length f6 of the sixth lens L6 and the total effective focal length f of the optical lens; the total optical length TTL of the optical lens and the total effective focal length f of the optical lens satisfy that TTL/f is 3.245.

In summary, examples 1 to 4 each satisfy the relationship shown in table 13 below.

Conditional expression (A) example	E1	E2	E3	E4
					f2/f	18.981	18.940	18.965	18.925
f6/f	2.042	2.041	2.044	2.040
					TTL/f	3.248	3.248	3.252	3.245

Watch 13

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. The optical lens sequentially comprises from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens,

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

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

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 and the fifth lens are glued to form a glued lens; and

the sixth lens has a positive optical power,

wherein the number of lenses having a power in the optical lens is six, an

The effective focal length f2 of the second lens and the total effective focal length f of the optical lens satisfy 14 ≤ f2/f ≤ 24.

2. An optical lens according to claim 1,

the fourth lens in the cemented lens has positive focal power, and both the object-side surface and the image-side surface of the cemented lens are convex surfaces; and

the fifth lens of the cemented lens has a negative optical power, and both the object-side surface and the image-side surface thereof are concave.

3. An optical lens barrel according to claim 1, wherein the object-side surface and the image-side surface of the sixth lens element are convex at the paraxial region.

4. An optical lens according to claim 1, wherein the first lens to the sixth lens include two aspherical lenses.

5. An optical lens according to claim 4, characterized in that the second lens and the sixth lens are plastic aspherical lenses.

6. An optical lens barrel according to any one of claims 1 to 5, wherein the object side surface of the sixth lens element is concave at the paraxial region and the image side surface of the sixth lens element is convex at the paraxial region.

7. An optical lens according to any one of claims 1 to 5, characterized in that an effective focal length f6 of the sixth lens and a total effective focal length f of the optical lens satisfy 1.8 ≦ f6/f ≦ 2.4.

8. An optical lens according to any one of claims 1 to 5, wherein an optical total length TTL of the optical lens and a total effective focal length f of the optical lens satisfy TTL/f ≦ 3.8.

9. The optical lens sequentially comprises from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens,

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

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

the sixth lens has positive optical power;

the total optical length TTL of the optical lens and the total effective focal length f of the optical lens meet the condition that TTL/f is less than or equal to 3.8,

wherein the number of lenses having a power in the optical lens is six, an

10. An optical lens barrel according to claim 9, wherein the object-side surface and the image-side surface of the sixth lens element are convex at the paraxial region.

11. An optical lens according to claim 9, wherein the first lens to the sixth lens include two aspherical lenses.

12. An optical lens according to claim 11, characterized in that the second lens and the sixth lens are plastic aspherical lenses.

13. An optical lens according to any one of claims 9 to 12, characterized in that an effective focal length f6 of the sixth lens and a total effective focal length f of the optical lens satisfy 1.8 ≦ f6/f ≦ 2.4.

14. An optical lens according to any one of claims 9 to 12, characterized in that the fourth lens is cemented with the fifth lens to constitute a cemented lens.

15. An optical lens barrel according to any one of claims 9 to 12, wherein the object side surface of the sixth lens element is concave at the distal axis, and the image side surface of the sixth lens element is convex at the distal axis.