CN109001887B - Optical lens - Google Patents

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 image side surface of the first lens is a concave surface; the second lens and the third lens are cemented to form a first cemented lens; the fourth lens and the fifth lens are cemented to form a second cemented lens; and the sixth lens has positive focal power, and both the object-side surface and the image-side surface of the sixth lens are convex.

Description

Optical lens

Technical Field

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

Background

Currently, a vehicle-mounted lens is generally applied to a vehicle-mounted driving assistance system to assist a driver in driving, even to automatically drive. With the popularization of the use of the vehicle-mounted lens, higher requirements are put forward on the aspects of image definition, picture comfort and the like.

The conventional technology generally increases the number of lenses to more than six sheets to obtain higher resolution capability. However, increasing the number of lenses affects miniaturization of the lens, which is not favorable for installation and use of the lens, and also increases the cost of the lens. In addition, an aspheric lens is generally used to correct aberration in the conventional art, and when a plastic aspheric lens is used, there is a problem of out-of-focus image blur caused by temperature change due to a large coefficient of thermal expansion of plastic; when a glass aspheric lens is used, the cost of the lens is too high.

Therefore, it is desirable to provide an optical lens that is applicable to vehicle-mounted mounting, has good temperature stability, high contrast, small chromatic aberration, and high resolution, and satisfies both miniaturization and low cost.

Disclosure of Invention

The technical solution provided by the present application at least partially solves the technical problems described above.

According to an aspect of the present application, there is provided an optical lens including, 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 and a sixth lens. The first lens has negative focal power, and the image side surface of the first lens is a concave surface; the second lens and the third lens are cemented to form a first cemented lens; the fourth lens and the fifth lens are cemented to form a second cemented lens; and the sixth lens has positive focal power, and both the object-side surface and the image-side surface of the sixth lens are convex.

In one embodiment, the object side surface of the first lens is convex.

In one embodiment, the object side surface of the first lens is concave.

In one embodiment, the second lens of the first cemented lens has a negative power with a convex object-side surface and a concave image-side surface; and the third lens in the first cemented lens has positive focal power, and both the object-side surface and the image-side surface of the third lens are convex surfaces.

In one embodiment, the second lens of the first cemented lens has positive optical power, with both the object-side surface and the image-side surface being convex; and the third lens in the first cemented lens has negative power, and the object-side surface thereof is concave. Optionally, the image-side surface of the third lens element may be convex; alternatively, the image-side surface of the third lens may also be concave.

In one embodiment, the fourth lens of the second cemented lens has a negative optical power, with both the object-side surface and the image-side surface being concave; and the fifth lens in the second cemented lens has positive optical power, and both the object-side surface and the image-side surface of the fifth lens are convex surfaces.

In one embodiment, the sixth lens is an aspheric lens.

In one embodiment, the focal length f23 of the first cemented lens and the total focal length f of the optical lens may satisfy 1 ≦ f23/f ≦ 2.1.

In one embodiment, the focal length f45 of the second cemented lens and the total focal length f of the optical lens may satisfy-7. ltoreq. f 45/f. ltoreq-1.

In one embodiment, the on-axis distance BFL from the center of the image side surface of the sixth lens element to the imaging surface of the optical lens and the on-axis distance TTL from the center of the object side surface of the first lens element to the imaging surface of the optical lens satisfy BFL/TTL ≧ 0.3.

In one embodiment, the on-axis distance TTL from the center of the object side surface of the first lens to the imaging surface of the optical lens and the total focal length f of the optical lens can satisfy TTL/f ≦ 10. More specifically, the on-axis distance TTL from the center of the object side surface of the first lens element to the imaging surface of the optical lens and the total focal length f of the optical lens satisfy TTL/f ≦ 6.5.

According to another aspect of the present application, there is also provided an optical lens, in order from an object side to an image side along an optical axis, comprising: the lens comprises a first lens, a first cemented lens formed by the second lens and the third lens through cementing, a second cemented lens formed by the fourth lens and the fifth lens through cementing, and a sixth lens. Wherein the focal length f23 of the first cemented lens and the total focal length f can satisfy 1 ≤ f23/f ≤ 2.1; the focal length f45 and the total focal length f of the second cemented lens can satisfy-7 ≤ f45/f ≤ 1.

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

In one embodiment, the first lens has a negative optical power and both the object-side surface and the image-side surface are concave.

In one embodiment, the sixth lens element has positive optical power and both the object-side surface and the image-side surface are convex.

In one embodiment, the second lens of the first cemented lens has a negative power with a convex object-side surface and a concave image-side surface; and the third lens in the first cemented lens has positive focal power, and both the object-side surface and the image-side surface of the third lens are convex surfaces.

In one embodiment, the second lens of the first cemented lens has positive optical power, with both the object-side surface and the image-side surface being convex; and the third lens in the first cemented lens has negative power, and the object-side surface thereof is concave. Optionally, the image-side surface of the third lens element may be convex; alternatively, the image-side surface of the third lens may also be concave.

In one embodiment, the fourth lens of the second cemented lens has a negative optical power, with both the object-side surface and the image-side surface being concave; and the fifth lens in the second cemented lens has positive optical power, and both the object-side surface and the image-side surface of the fifth lens are convex surfaces.

In one embodiment, the sixth lens is an aspheric lens.

In one embodiment, the on-axis distance BFL from the center of the image side surface of the sixth lens element to the imaging surface of the optical lens and the on-axis distance TTL from the center of the object side surface of the first lens element to the imaging surface of the optical lens satisfy BFL/TTL ≧ 0.3.

In one embodiment, the on-axis distance TTL from the center of the object side surface of the first lens to the imaging surface of the optical lens and the total focal length f of the optical lens can satisfy TTL/f ≦ 10. More specifically, the on-axis distance TTL from the center of the object side surface of the first lens element to the imaging surface of the optical lens and the total focal length f of the optical lens satisfy TTL/f ≦ 6.5.

The optical lens can adopt spherical glass lenses and avoid adopting aspheric lenses, so that the requirement of high resolution can be met, and the requirements of low cost and stable temperature performance can be met. Under the condition of not considering the low cost or temperature performance requirement, an aspheric lens can be adopted mostly, so that the optical performance of the lens is better. Meanwhile, the two groups of the cemented lenses are beneficial to correcting aberration, realizing high-resolution and compact integral structure of an optical system, meeting the miniaturization requirement and reducing tolerance sensitivity problems such as inclination and/or core deviation and the like of the lens units in the assembling process.

This application has adopted the multi-disc (for example, six) lenses, through the focal power, the face type of rational distribution each lens of optical lens to and each lens interval distance's rational distribution, at the in-process that reduces the temperature and to optical lens performance influence, make the system have following at least one beneficial effect:

the illumination of the lens is improved;

the resolution of the optical lens is improved;

the miniaturization of the lens is realized;

reduced sensitivity of the optical system, easy to assemble;

the cost of the lens is reduced;

correcting various aberrations; and

the resolution and the imaging quality of the lens are improved.

Drawings

Other features, objects and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments thereof, 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 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," "includes," "including," "has," "including," and/or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, 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 may include, 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.

According to embodiments of the present application, the first lens may have a negative optical power, with its image-side surface being concave. The first lens can have negative focal power and low refractive index, so that the excessive divergence of object light rays is effectively avoided, and the aperture of the rear lens is favorably controlled. The first lens can have a higher abbe number to facilitate reduction of the overall chromatic aberration of the optical system. In some embodiments, the object side surface of the first lens can be convex. When the object side surface of the first lens is convex, the light rays can be collected and enter the optical system as much as possible; meanwhile, considering that the environment for outdoor installation and use of the vehicle-mounted lens is possibly severe, the object side surface of the first lens is configured to be a convex surface, and the falling of water drops on the object side surface is facilitated, so that the influence of severe weather such as rain and snow on the imaging quality of the lens is reduced. In other embodiments, the object side surface of the first lens can be concave. When the object side surface of the first lens is a concave surface, the expansion of the view field angle of the optical lens and the reduction of the aperture of the front end of the lens are facilitated, so that the reduction of the whole volume of the lens is facilitated; meanwhile, the object side surface of the first lens is arranged to be a concave surface, so that the distortion can be moderately increased, and the lens is suitable for a vehicle event recorder and the like which need to focus on observing a front small-range image.

The second lens can have positive power or negative power, and the object side surface of the second lens can be a convex surface. The image side surface of the first lens is a concave surface, and the object side surface of the second lens is arranged to be a convex surface, so that the distance between the first lens and the second lens is reduced, the physical total length of the optical lens is shortened, and the miniaturization of the optical lens is realized. The convex arrangement of the object side surface of the second lens is also beneficial to reducing the optical incident angle of the peripheral incident to the object side surface of the second lens, so that the energy loss of light rays reflected on the surface of the lens is reduced, and the illumination of the lens is promoted. In addition, because the two opposite concave surfaces are easy to generate cross reflection light, and the generated cross reflection light enters the imaging surface to interfere the imaging picture effect, the image side surface of the first lens is a concave surface, and the object side surface of the second lens is a convex surface, so that stray light caused by cross reflection between the first lens and the second lens can be reduced.

The second lens and the third lens are cemented to form a first cemented lens. Wherein the second lens and the third lens can be cemented in a variety of configurations. For example, the second lens may be a meniscus lens having a negative power convex toward the object side, and the third lens cemented with the second lens may be a double convex lens having a positive power. For another example, the second lens may be a double convex lens having a positive power, and the third lens cemented with the second lens may be a meniscus lens having a negative power convex toward the image side; or the second lens may be a double convex lens having a positive power and the third lens cemented with the second lens may be a double concave lens having a negative power. The focal length f23 of the cemented first lens composed of the cemented second and third lenses and the total focal length f of the optical lens may satisfy 1. ltoreq. f 23/f.ltoreq.2.1, and more specifically, f23 and f may further satisfy 1.33. ltoreq. f 23/f.ltoreq.1.71.

And the fourth lens and the fifth lens are cemented to form a second cemented lens. 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 focal length f45 of the second cemented lens composed of the fourth lens cemented with the fifth lens and the total focal length f of the optical lens may satisfy-7. ltoreq. f 45/f.ltoreq.1, more specifically, f45 and f may further satisfy-6.38. ltoreq. f 45/f.ltoreq.3.38.

The first cemented lens and the second cemented lens each include one piece of a lens having positive optical power and one piece of a lens having negative optical power. One lens has a high refractive index and a low Abbe number, the other lens has a low refractive index (relative to the lens with the high refractive index) and a high Abbe number (relative to the lens with the low Abbe number), and the matching of the high refractive index and the low refractive index of the lens is beneficial to the rapid transition of front light and the increase of the aperture of the diaphragm, so that the lens meets the requirement of night vision. The use of the cemented lens also enables the overall structure of the optical system to be more compact while effectively reducing the chromatic aberration of the system.

The use of two groups of cemented lenses shares the whole chromatic aberration correction of the system, and the two groups of cemented lenses are respectively positioned at the two sides of the diaphragm, thereby effectively correcting the chromatic aberration, shortening the optical total length of the system and improving the resolving power of the lens. In addition, the use of two groups of cemented lenses is also beneficial to reducing tolerance sensitivity problems of inclination and/or core deviation of the lens units generated in the assembling process.

Optionally, in order to improve the optical performance of the lens barrel, an aspheric lens may be used as any one of the first lens to the fifth lens, or a lens with at least one aspheric mirror surface may be used. In particular, the adhesive surface between the second lens and the third lens and/or the adhesive surface between the fourth lens and the fifth lens can use an aspheric mirror surface to further improve the performance of the lens. When the requirement on the temperature stability of the lens is not high, the plastic aspheric lens can be adopted to reduce the cost and the overall weight of the system.

The sixth lens element can have a positive optical power and both the object-side surface and the image-side surface are convex. The sixth lens may employ an aspherical lens so that light can be efficiently and smoothly converged at the sixth lens. Optionally, the sixth lens may be a lens made of plastic material, so as to reduce the overall weight and cost of the system.

An axial distance BFL between the center of the image-side surface of the last lens (when the lens includes six lenses, the last lens is the sixth lens) of the optical lens and the imaging surface of the optical lens, and an optical total length TTL of the optical lens (that is, an axial distance from the center of the object-side surface of the first lens to the imaging surface of the optical lens) can satisfy that BFL/TTL is more than or equal to 0.3, and more specifically, between BFL and TTL, further satisfies that BFL/TTL is more than or equal to 0.35 and less than or equal to 0.49. The back focal length is large, and the tolerance of the module for focusing is large when the module is assembled; in the case of a constant total length, the longer the back focus, the shorter the length of the lens itself, and the lower the cost.

An overall optical length TTL (i.e., an on-axis distance from a center of an object-side surface of the first lens element to an imaging surface of the optical lens) of the optical lens and an overall focal length f of the optical lens may satisfy TTL/f ≦ 10, more specifically, TTL and f may further satisfy TTL/f ≦ 6.5, and still further, may satisfy 3.67 ≦ TTL/f ≦ 4.48.

In the optical lens according to the exemplary embodiment of the present application, the requirement of high resolution can be satisfied by adopting spherical glass lenses and avoiding adopting aspheric lenses, and meanwhile, the requirements of low cost and stable temperature performance can be satisfied. Under the condition of not considering the cost or having lower requirements on temperature performance, an aspheric lens can be adopted in many cases, so that the optical performance of the lens is better.

The lens barrel according to the above-described embodiment of the present application may employ a plurality of lenses, for example, six lenses as described above. By reasonably distributing the focal power and the surface type of each lens, the thickness of each lens, the on-axis distance and the like, the lens has high illumination, small chromatic aberration and high resolution while the temperature performance is stable. In addition, the lens configured in the mode also has 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.

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 six lenses L1-L6 arranged in order from the object side to the image side along the optical axis. The first lens L1 is a biconcave lens with negative power, and both the object-side surface S1 and the image-side surface S2 are concave; the second lens L2 is a meniscus lens with negative power, with the object-side S3 being convex and the image-side S4 being concave; the third lens L3 is a biconvex lens with positive optical power, and both the object-side surface S4 and the image-side surface S5 are convex; the fourth lens L4 is a biconcave lens with negative power, and both the object-side surface S7 and the image-side surface S8 are concave; the fifth lens L5 is a biconvex lens with positive optical power, and both the object-side surface S8 and the image-side surface S9 are convex; and the sixth lens L6 is a biconvex lens with positive optical power, and both the object-side surface S10 and the image-side surface S11 are convex. Wherein, the second lens L2 and the third lens L3 are cemented to form a first cemented lens. The fourth lens L4 and the fifth lens L5 are cemented to constitute a second cemented lens. In the optical lens of the present embodiment, a stop STO may also be provided between, for example, the third lens L3 and the fourth lens L4 to improve the imaging quality. Optionally, the optical lens further includes a filter L7 having an object-side surface S12 and an image-side surface S13 and/or a protective glass L8 having an object-side surface S14 and an image-side surface S15. The light from the object sequentially passes through the respective surfaces S1 to S15 and is finally imaged on the imaging surface S16.

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.

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					S1	-19.3754	1.0000	1.55	67.00
S2	3.3061	1.3807
					S3	14.1804	0.6000	1.50	81.00
S4	5.3208	1.8000	1.92	20.88
					S5	-180.0000	0.1540
STO	Infinity	0.2014
					S7	-12.0818	1.5213	1.92	20.88
S8	6.2974	2.1000	1.69	54.57
					S9	-10.7424	0.1000
S10	10.8740	2.6057	1.62	63.41
					S11	-5.6444	0.5132
S12	Infinity	0.5500	1.52	64.20
					S13	Infinity	5.8625
S14	Infinity	0.4000	1.52	64.20
					S15	Infinity	0.1250
S16	Infinity

TABLE 1

In the embodiment, six lenses are taken as an example, and the focal length and the surface type of each lens are reasonably distributed, so that the lens meets the requirements of low cost, stable temperature performance and the like while the miniaturization is ensured, and the resolution of the lens is improved. Each aspherical surface type Z is defined by the following 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 high-order term coefficients A, B, C, D and E that can be used for each of the aspherical lens surfaces S10 and S11 in example 1.

Flour mark

k

A

B

C

D

E

10

-13.7113

1.0151E-03

-9.4019E-05

6.6690E-06

-2.4831E-07

4.0257E-08

11

-2.7582

-1.2074E-03

3.5860E-05

-3.2291E-06

2.4129E-07

-5.8247E-08

TABLE 2

In the present embodiment, the focal length f23 of the first cemented lens formed by the second lens L2 cemented with the third lens L3 and the total focal length f of the optical lens satisfy f 23/f-1.71; the focal length f45 of the second cemented lens formed by the fourth lens L4 and the fifth lens L5 cemented together and the total focal length f of the optical lens satisfy f 45/f-5.14; an on-axis distance BFL from the center of the image-side surface S11 of the sixth lens L6 to the imaging surface S16 of the optical lens and an on-axis distance TTL from the center of the object-side surface S1 of the first lens L1 to the imaging surface S16 of the optical lens satisfy BFL/TTL of 0.39; an on-axis distance TTL from the center of the object-side surface S1 of the first lens L1 to the imaging surface S16 of the optical lens and a total focal length f of the optical lens satisfy TTL/f of 3.92.

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 six lenses L1-L6 arranged in order from the object side to the image side along the optical axis. The first lens L1 is a biconcave lens with negative power, and both the object-side surface S1 and the image-side surface S2 are concave; the second lens L2 is a biconvex lens with positive optical power, and both the object-side surface S3 and the image-side surface S4 are convex; the third lens L3 is a meniscus lens with negative power, with the object-side S4 being concave and the image-side S5 being convex; the fourth lens L4 is a biconcave lens with negative power, and both the object-side surface S7 and the image-side surface S8 are concave; the fifth lens L5 is a biconvex lens with positive optical power, and both the object-side surface S8 and the image-side surface S9 are convex; and the sixth lens L6 is a biconvex lens with positive optical power, and both the object-side surface S10 and the image-side surface S11 are convex. Wherein, the second lens L2 and the third lens L3 are cemented to form a first cemented lens. The fourth lens L4 and the fifth lens L5 are cemented to constitute a second cemented lens. In the optical lens of the present embodiment, a stop STO may also be provided between, for example, the third lens L3 and the fourth lens L4 to improve the imaging quality. Optionally, the optical lens further includes a filter L7 having an object-side surface S12 and an image-side surface S13 and/or a protective glass L8 having an object-side surface S14 and an image-side surface S15. The light from the object sequentially passes through the respective surfaces S1 to S15 and is finally imaged on the imaging surface S16.

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 5 shows the conic coefficients k and high-order term coefficients A, B, C, D and E that can be used for each of the aspherical lens surfaces S10 and S11 in example 2. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					S1	-13.0223	0.9755	1.52	64.21
S2	3.0604	1.2534
					S3	13.7041	1.5716	1.92	20.88
S4	-5.5413	0.6000	1.49	70.42
					S5	-27.0137	0.1502
STO	Infinity	0.0976
					S7	-10.2521	1.2317	1.90	22.00
S8	3.3146	2.0486	1.71	54.57
					S9	-9.8599	0.0976
S10	8.3647	3.1357	1.58	64.00
					S11	-5.5527	0.5006
S12	Infinity	0.5500	1.52	64.21
					S13	Infinity	4.2000
S14	Infinity	0.4000	1.52	64.21
					S15	Infinity	0.3229
S16	Infinity

TABLE 3

Flour mark

k

A

B

C

D

E

10

-5.4864

1.4092E-03

1.2235E-04

1.1628E-04

1.7641E-06

-5.4949E-07

11

-2.3282

-1.4233E-03

5.8421E-04

-1.0685E-04

1.1116E-05

-3.7203E-07

TABLE 4

In the present embodiment, the focal length f23 of the first cemented lens formed by the second lens L2 cemented with the third lens L3 and the total focal length f of the optical lens satisfy f 23/f-1.33; the focal length f45 of the second cemented lens formed by the fourth lens L4 and the fifth lens L5 cemented together and the total focal length f of the optical lens satisfy f 45/f-3.38; an on-axis distance BFL from the center of the image-side surface S11 of the sixth lens L6 to the imaging surface S16 of the optical lens and an on-axis distance TTL from the center of the object-side surface S1 of the first lens L1 to the imaging surface S16 of the optical lens satisfy BFL/TTL of 0.35; an on-axis distance TTL from the center of the object-side surface S1 of the first lens L1 to the imaging surface S16 of the optical lens and a total focal length f of the optical lens satisfy TTL/f of 3.67.

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 six lenses L1-L6 arranged in order from the object side to the image side along the optical axis. The first lens L1 is a biconcave lens with negative power, and both the object-side surface S1 and the image-side surface S2 are concave; the second lens L2 is a biconvex lens with positive optical power, and both the object-side surface S3 and the image-side surface S4 are convex; the third lens L3 is a biconcave lens with negative power, and both the object-side surface S4 and the image-side surface S5 are concave; the fourth lens L4 is a biconcave lens with negative power, and both the object-side surface S7 and the image-side surface S8 are concave; the fifth lens L5 is a biconvex lens with positive optical power, and both the object-side surface S8 and the image-side surface S9 are convex; and the sixth lens L6 is a biconvex lens with positive optical power, and both the object-side surface S10 and the image-side surface S11 are convex. Wherein, the second lens L2 and the third lens L3 are cemented to form a first cemented lens. The fourth lens L4 and the fifth lens L5 are cemented to constitute a second cemented lens. In the optical lens of the present embodiment, a stop STO may also be provided between, for example, the third lens L3 and the fourth lens L4 to improve the imaging quality. Optionally, the optical lens further includes a filter L7 having an object-side surface S12 and an image-side surface S13 and/or a protective glass L8 having an object-side surface S14 and an image-side surface S15. The light from the object sequentially passes through the respective surfaces S1 to S15 and is finally imaged on the imaging surface S16.

Table 5 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 6 shows the conic coefficients k and high-order term coefficients A, B, C, D and E that can be used for each of the aspherical lens surfaces S10 and S11 in example 3. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					S1	-19.5734	1.0000	1.60	641.00
S2	3.4991	1.2576
					S3	9.8633	2.0000	1.92	20.88
S4	-12.2190	0.6401	1.49	70.42
					S5	21.8607	0.4134
STO	Infinity	0.2134
					S7	-11.3190	1.4243	1.92	20.88
S8	6.1053	2.5000	1.69	54.57
					S9	-9.1042	0.1067
S10	9.5682	3.2005	1.55	63.41
					S11	-6.3464	0.5475
S12	Infinity	0.5500	1.52	64.20
					S13	Infinity	10.7021
S14	Infinity	0.4000	1.52	64.21
					S15	Infinity	0.1250
S16	Infinity

TABLE 5

Flour mark

k

A

B

C

D

E

10

-15.2664

1.4329E-03

4.2254E-05

-1.8332E-05

2.7297E-06

-1.2439E-07

11

-10.2536

-1.0122E-03

1.6036E-05

-2.1647E-05

2.1144E-06

-6.6152E-07

TABLE 6

In the present embodiment, the focal length f23 of the first cemented lens formed by the second lens L2 cemented with the third lens L3 and the total focal length f of the optical lens satisfy f23/f 1.63; the focal length f45 of the second cemented lens formed by the fourth lens L4 and the fifth lens L5 cemented together and the total focal length f of the optical lens satisfy f 45/f-5.98; an on-axis distance BFL from the center of the image-side surface S11 of the sixth lens L6 to the imaging surface S16 of the optical lens and an on-axis distance TTL from the center of the object-side surface S1 of the first lens L1 to the imaging surface S16 of the optical lens satisfy BFL/TTL of 0.49; an on-axis distance TTL from the center of the object-side surface S1 of the first lens L1 to the imaging surface S16 of the optical lens and a total focal length f of the optical lens satisfy TTL/f of 4.48.

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 six lenses L1-L6 arranged in order from the object side to the image side along the optical axis. 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 biconvex lens with positive optical power, and both the object-side surface S3 and the image-side surface S4 are convex; the third lens L3 is a biconcave lens with negative power, and both the object-side surface S4 and the image-side surface S5 are concave; the fourth lens L4 is a biconcave lens with negative power, and both the object-side surface S7 and the image-side surface S8 are concave; the fifth lens L5 is a biconvex lens with positive optical power, and both the object-side surface S8 and the image-side surface S9 are convex; and the sixth lens L6 is a biconvex lens with positive optical power, and both the object-side surface S10 and the image-side surface S11 are convex. Wherein, the second lens L2 and the third lens L3 are cemented to form a first cemented lens. The fourth lens L4 and the fifth lens L5 are cemented to constitute a second cemented lens. In the optical lens of the present embodiment, a stop STO may also be provided between, for example, the third lens L3 and the fourth lens L4 to improve the imaging quality. Optionally, the optical lens further includes a filter L7 having an object-side surface S12 and an image-side surface S13 and/or a protective glass L8 having an object-side surface S14 and an image-side surface S15. The light from the object sequentially passes through the respective surfaces S1 to S15 and is finally imaged on the imaging surface S16.

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 4. Table 8 shows the conic coefficients k and high-order term coefficients A, B, C, D and E that can be used for each of the aspherical lens surfaces S10 and S11 in example 4. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

TABLE 7

Flour mark

k

A

B

C

D

E

10

-23.8061

5.0872E-04

-8.3036E-05

-1.4208E-05

2.1059E-06

-1.8328E-07

11

-11.8265

-1.8058E-03

2.7233E-04

-2.5745E-05

3.4192E-06

-2.2393E-07

TABLE 8

In the present embodiment, the focal length f23 of the first cemented lens formed by the second lens L2 cemented with the third lens L3 and the total focal length f of the optical lens satisfy f 23/f-1.64; the focal length f45 of the second cemented lens formed by the fourth lens L4 and the fifth lens L5 cemented together and the total focal length f of the optical lens satisfy f 45/f-6.38; an on-axis distance BFL from the center of the image-side surface S11 of the sixth lens L6 to the imaging surface S16 of the optical lens and an on-axis distance TTL from the center of the object-side surface S1 of the first lens L1 to the imaging surface S16 of the optical lens satisfy BFL/TTL of 0.39; an on-axis distance TTL from the center of the object-side surface S1 of the first lens L1 to the imaging surface S16 of the optical lens and a total focal length f of the optical lens satisfy TTL/f of 4.23.

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

Conditional expression (A) example	1	2	3	4
					f23/f	1.71	1.33	1.63	1.64
f45/f	-5.14	-3.38	-5.98	-6.38
					BFL/TTL	0.39	0.35	0.49	0.39
TTL/f	3.92	3.67	4.48	4.23

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 and the technical features (but not limited to) having similar functions disclosed in the present application are mutually replaced to constitute the technical solution.

Claims (23)

1. An optical lens includes six lenses having optical powers, namely a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the first lens to the sixth lens 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 concave surface, and the image side surface of the first lens is a concave surface;

the second lens and the third lens are cemented to form a first cemented lens, wherein the second lens has negative 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 fourth lens and the fifth lens are cemented to form a second cemented lens; and

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.

2. An optical lens according to claim 1,

the third lens in the first cemented lens has positive optical power, and both the object-side surface and the image-side surface of the third lens are convex surfaces.

3. An optical lens according to claim 1,

the fourth lens in the second cemented lens has negative optical power, and both the object-side surface and the image-side surface of the fourth lens are concave; and

the fifth lens in the second cemented lens has positive optical power, and both the object-side surface and the image-side surface are convex surfaces.

4. An optical lens according to any one of claims 1 to 3, characterized in that the sixth lens is an aspherical lens.

5. An optical lens according to any one of claims 1 to 3, characterized in that a focal length f23 of the first cemented lens and a total focal length f of the optical lens satisfy 1 ≦ f23/f ≦ 2.1.

6. An optical lens according to any one of claims 1 to 3, characterized in that a focal length f45 of the second cemented lens and a total focal length f of the optical lens satisfy-7 ≦ f45/f ≦ -1.

7. An optical lens barrel according to any one of claims 1 to 3, wherein an on-axis distance BFL from the center of the image-side surface of the sixth lens element to the imaging surface of the optical lens barrel and an on-axis distance TTL from the center of the object-side surface of the first lens element to the imaging surface of the optical lens barrel satisfy BFL/TTL ≧ 0.3.

8. An optical lens barrel according to any one of claims 1 to 3, wherein an on-axis distance TTL from a center of an object side surface of the first lens to an imaging surface of the optical lens and a total focal length f of the optical lens satisfy TTL/f ≦ 10.

9. An optical lens barrel according to claim 8, wherein an on-axis distance TTL from a center of an object-side surface of the first lens element to an image plane of the optical lens barrel and a total focal length f of the optical lens barrel satisfy TTL/f ≦ 6.5.

10. An optical lens having an overall focal length f, wherein the number of the optical lens having a focal power is six, and the optical lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the first lens to the sixth lens are sequentially disposed from an object side to an image side along an optical axis, the second lens is a first cemented lens formed by the second lens and the third lens cemented together, and the second cemented lens is a second cemented lens formed by the fourth lens and the fifth lens cemented together,

the focal length f23 of the first cemented lens and the total focal length f satisfy 1 ≤ f23/f ≤ 2.1;

the focal length f45 of the second cemented lens and the total focal length f satisfy-7 ≤ f45/f ≤ 1.

11. An optical lens as claimed in claim 10, characterized in that the first lens element has a negative optical power and has a convex object-side surface and a concave image-side surface.

12. An optical lens as recited in claim 10, wherein the first lens element has a negative optical power and both the object-side surface and the image-side surface are concave.

13. An optical lens barrel according to claim 10, wherein the sixth lens element has a positive optical power, and both the object-side surface and the image-side surface thereof are convex.

14. An optical lens according to claim 10,

the second lens in the first cemented lens has negative focal power, and the object-side surface of the second lens is a convex surface while the image-side surface of the second lens is a concave surface; and

the third lens in the first cemented lens has positive optical power, and both the object-side surface and the image-side surface of the third lens are convex surfaces.

15. An optical lens according to claim 10,

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

the third lens in the first cemented lens has a negative optical power, and its object-side surface is a concave surface.

16. An optical lens barrel according to claim 15, wherein the image side surface of the third lens element is convex.

17. An optical lens barrel according to claim 15, wherein the image side surface of the third lens is concave.

18. An optical lens according to claim 10,

the fourth lens in the second cemented lens has negative optical power, and both the object-side surface and the image-side surface of the fourth lens are concave; and

the fifth lens in the second cemented lens has positive optical power, and both the object-side surface and the image-side surface are convex surfaces.

19. An optical lens according to claim 13, characterized in that the sixth lens is an aspherical lens.

20. An optical lens barrel according to claim 10, wherein an on-axis distance BFL from the center of the image-side surface of the sixth lens element to the imaging surface of the optical lens barrel and an on-axis distance TTL from the center of the object-side surface of the first lens element to the imaging surface of the optical lens barrel satisfy BFL/TTL ≥ 0.3.

21. An optical lens barrel according to claim 10, wherein an on-axis distance TTL from a center of an object-side surface of the first lens element to an image plane of the optical lens barrel and a total focal length f of the optical lens barrel satisfy TTL/f ≦ 10.

22. An optical lens barrel according to claim 21, wherein an on-axis distance TTL from a center of an object-side surface of the first lens element to an image plane of the optical lens barrel and a total focal length f of the optical lens barrel satisfy TTL/f ≦ 6.5.

23. An optical lens assembly including six lenses having refractive powers, each of the lenses including a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element and a sixth lens element, wherein the first lens element to the sixth lens element are arranged in order from an object side to an image side along an optical axis,

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

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

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

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;

the focal length f45 of the second cemented lens and the total focal length f of the optical lens satisfy-7 ≤ f45/f ≤ 1.

Images