CN111352215B

CN111352215B - Optical lens and imaging apparatus

Info

Publication number: CN111352215B
Application number: CN201811581622.2A
Authority: CN
Inventors: 李响; 王东方; 姚波
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2018-12-24
Filing date: 2018-12-24
Publication date: 2022-02-25
Anticipated expiration: 2038-12-24
Also published as: CN111352215A

Abstract

An optical lens and an imaging apparatus including the same are disclosed. The optical lens sequentially comprises from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens has negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens has negative focal power, 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 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; and the sixth lens has a negative power. According to the optical lens, at least one of the beneficial effects of high resolution, small volume, low sensitivity, high production yield, avoidance of stray light generation, avoidance of color cast and dark angle phenomena, large aperture, good imaging effect, clear image at night and the like can be achieved.

Description

Optical lens and imaging apparatus

Technical Field

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

Background

With the rapid development of economy and the improvement of living standard of people, automobiles become one of essential tools for people to go out, and due to the rapid development of automobile auxiliary driving systems in recent years, optical lenses are more and more widely applied to automobiles. At present, the requirement on the resolution of a vehicle-mounted optical lens is higher and higher, and especially a front-view optical lens is continuously promoted from the original megapixels and pursues higher and higher resolution definition. To achieve higher resolution, resolution can often be increased by increasing the number of lenses, with aspheric corrective aberrations. However, the overall length of the system is often sacrificed to improve the resolution, which is contrary to the miniaturization trend of the optical lens for vehicle-mounted optical lens, and the cost is also greatly increased. In addition, such optical lenses require a larger aperture to enable use in low light environments; smaller CRAs are needed to match high pixel chips without color cast; less distortion is also required to reduce distortion of the imaged picture.

Therefore, an optical lens with high resolution and the characteristics of miniaturization, large aperture, small distortion, low cost and the like is needed at present, and the requirements of automatic driving application are met.

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 comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the first lens has negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens has negative focal power, 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 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; and the sixth lens has a negative power.

The sixth lens element has a concave object-side surface and a convex image-side surface.

The object side surface and the image side surface of the sixth lens respectively comprise at least one inflection point.

The fourth lens and the fifth lens are double-cemented lenses, wherein the double-cemented lens means that the image side surface of the fourth lens is connected with the object side surface of the fifth lens through a cement material.

At least two lenses of the first lens to the sixth lens are aspheric lenses.

The second lens, the third lens and the sixth lens are aspheric lenses.

The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all made of glass materials.

The optical lens further comprises a diaphragm, and the diaphragm is arranged between the third lens and the fourth lens.

The optical lens is characterized in that 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 6.5.

Wherein D/h/FOV is less than or equal to 0.05, and the FOV is the maximum field angle of the optical lens; d is the maximum light-passing aperture of the object side surface of the first lens corresponding to the maximum field angle of the optical lens; and h is the image height corresponding to the maximum field angle of the optical lens.

Wherein, the total optical length TTL of the optical lens and the optical back focus BFL of the optical lens meet that BFL/TTL is more than or equal to 0.03 and less than or equal to 0.3.

And the half aperture d of the maximum light transmission aperture of the object side surface of the second lens corresponding to the maximum field angle of the optical lens and the corresponding Sg value SAG meet the requirement that arctan (SAG/d) is less than or equal to 40.

The center curvature radius R5 of the object side surface of the third lens of the optical lens and the center curvature radius R6 of the image side surface of the third lens of the optical lens meet the requirement that (R5+ R6)/(R5-R6) is more than or equal to-0.4 and less than or equal to 0.

Wherein, TTL/h/FOV is less than or equal to 0.05, and TTL is the total optical length of the optical lens; h is the image height corresponding to the maximum field angle of the optical lens; and FOV is the maximum field angle of the optical lens.

The fourth lens focal length F4 of the optical lens and the fifth lens focal length F5 of the optical lens meet the condition that | F4/F5| is less than or equal to 5.

The combined focal length F45 of the fourth lens and the fifth lens of the optical lens and the total effective focal length F of the optical lens satisfy F45/F ≤ 20.

Wherein, the FOV f/h is less than or equal to 80, and the FOV is the maximum field angle of the optical lens; f is the total effective focal length of the optical lens; and h is the image height corresponding to the maximum field angle of the optical lens.

Another aspect of the present application provides 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 second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the first lens and the second lens both have negative focal power; the third lens and the fourth lens both have positive focal power; the fifth lens and the sixth lens both have negative focal power; the fourth lens and the fifth lens are mutually glued to form a double-glued lens; and the total optical length TTL of the optical lens and the total effective focal length f of the optical lens meet that TTL/f is less than or equal to 6.5.

The first lens element has a convex object-side surface and a concave image-side surface.

The second lens element has a convex object-side surface and a concave image-side surface.

The object-side surface and the image-side surface of the third lens are convex surfaces.

The object-side surface and the image-side surface of the fourth lens are convex surfaces.

And the object side surface and the image side surface of the fifth lens are both concave surfaces.

At least two lenses of the first lens to the sixth lens are aspheric lenses.

The second lens, the third lens and the sixth lens are aspheric lenses.

A further aspect of the present application provides an imaging apparatus that may include the optical lens of the above embodiment and an imaging element for converting an optical image formed by the optical lens into an electrical signal.

This application has adopted six glass lenses for example, through the shape, the focal power of optimizing each lens of setting, air interval between the rational distribution adjacent lens etc. make optical lens have following at least one beneficial effect: high resolution is realized, and the requirements of small lens size, low sensitivity and high production yield are met; the main ray angle (CRA) of the optical lens is small, so that stray light generated by the fact that the rear end of light rays is emitted to the lens barrel can be avoided, the optical lens can be matched with a vehicle-mounted chip, and color cast and dark corner phenomena cannot be generated; the optical lens has a large aperture, the imaging effect is good, the image quality can reach a million high-definition level, and the image definition can be ensured in a low-light environment or at night.

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 partial side view of a second lens;

fig. 2 is a schematic structural view showing an optical lens according to embodiment 1 of the present application;

fig. 3 is a schematic structural view showing an optical lens according to embodiment 2 of the present application; and fig. 4 is a schematic view showing a structure of an optical lens according to embodiment 3 of the present application.

Detailed Description

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

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens 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 of the lens, and the surface of each lens closest to the imaging surface is called 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 along the optical axis in sequence from the object side to the image side.

The first lens element can have a negative power, and can have a convex object-side surface and a concave image-side surface. The first lens is a converging lens with negative focal power, the shape of the first lens is a meniscus shape facing an object space, and light can be collected and enter a rear optical system, so that the light flux is increased, and the whole large field range is realized. In practical application, 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 into a convex surface, so that water drops on the object side surface can slide off, and the influence of severe weather such as rain and snow on the imaging quality of the lens is reduced.

The second lens element can have a negative power, and has a convex object-side surface and a concave image-side surface. The arrangement of the second lens as a negative power lens in a meniscus shape convex toward the object side is advantageous for smooth transition of the light rays exiting through the first lens to the third lens, and also for correction of high-order aberrations, contributing to reduction in the degree of attenuation of the relative illuminance of the optical lens. In an exemplary embodiment, to improve the resolution, the second lens preferably uses an aspherical mirror.

The third lens element can have a positive optical power, and both the object-side surface and the image-side surface can be convex. The third lens with positive focal power can quickly converge the front large-angle light to the fourth lens, so that the reduction of the optical path of the rear light is facilitated, the total optical length TTL of the short optical lens is realized, and the tolerance sensitivity problems of inclination/core deviation and the like of the lenses in the assembling process are reduced. In an exemplary embodiment, to improve the resolution, the third lens preferably uses an aspherical mirror.

The fourth lens element can have a positive optical 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 can be double-cemented lenses, wherein the double-cemented lenses are formed by connecting the image side surface of the fourth lens with the object side surface of the fifth lens through a cement material. The fourth lens element can further converge the light rays, reduce the total track length TTL of the optical lens, and have a lower refractive index. The fifth lens may be posterior, having a higher index of refraction (relative to the fourth lens). The fourth lens and the fifth lens can be matched with each other in a high-refractive-index and low-refractive-index mode, and rapid transition of front light is facilitated. Advantages of the configuration in which the fourth lens and the fifth lens may be double cemented lenses include: the air space between the fourth lens and the fifth lens can be reduced, and the total length of the system is reduced; the assembling parts between the fourth lens and the fifth lens can be reduced, the working procedures are reduced, and the cost is reduced; the tolerance sensitivity problems of inclination/core deviation and the like of the lens generated in the assembling process can be reduced; the light quantity loss caused by reflection between the lenses can be reduced, and the illumination intensity is improved; curvature of field may be reduced to correct for off-axis point aberrations of the system; the system can share the whole chromatic aberration correction of the system, effectively correct the aberration, improve the resolving power, make the optical system compact as a whole and meet the miniaturization requirement.

Optionally, a diaphragm may be disposed between the third lens and the fourth lens to improve the imaging quality of the imaging lens, reduce the aperture of the front end of the system, and implement a large aperture. In exemplary embodiments, the diaphragm may be disposed in other positions as desired.

The sixth lens element can have a negative power, and can have a concave object-side surface and a convex image-side surface, and the overall shape of the sixth lens element can be a meniscus shape convex toward the image-side surface. The sixth lens can ensure that the light of the fifth lens is smoothly transited to an imaging surface, so that the total optical length TTL of the optical lens is favorably reduced, and various aberrations of the optical system are fully corrected. In addition, on the premise of compact structure, the resolution can be improved, and the optical performances such as distortion, a principal ray angle (CRA) and the like can be optimized. In an exemplary embodiment, to improve the resolution, the sixth lens preferably uses an aspherical mirror. In an exemplary embodiment, the object-side surface and the image-side surface of the sixth lens each comprise at least one inflection point.

The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens can all be lenses made of all-glass materials. The optical lens is mainly made of glass lenses, so that the requirements on low cost, stable temperature performance and the like are met.

In an exemplary embodiment, TTL/f ≦ 6.5 may be satisfied between the total optical length TTL of the optical lens and the total effective focal length f of the optical lens, and more particularly, TTL and f may further satisfy TTL/f ≦ 5, e.g., 4.77 ≦ TTL/f ≦ 4.85. The condition formula TTL/f is less than or equal to 6.5, and the miniaturization of the lens is favorably realized.

In an exemplary embodiment, D/h/FOV ≦ 0.05 may be satisfied between the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens, and particularly, D, h and FOV may further satisfy D/h/FOV ≦ 0.04, for example, 0.01 ≦ D/h/FOV ≦ 0.02. The conditional expression D/h/FOV is less than or equal to 0.05, and the small caliber at the front end of the lens can be realized.

In an exemplary embodiment, the total optical length TTL of the optical lens and the optical back focus BFL of the optical lens satisfy 0.03 ≦ BFL/TTL ≦ 0.3, and specifically, TTL and BFL may further satisfy 0.05 ≦ BFL/TTL ≦ 0.18, e.g., 0.1 ≦ BFL/TTL ≦ 0.11. Satisfies the conditional expression of BFL/TTL is less than or equal to 0.03 and less than or equal to 0.3, and can be combined with the whole framework to avoid that the back focal length is too short to be assembled or the total length of the lens group is too long caused by too long back focal length.

Fig. 1 is a partial side view of a second lens. In an exemplary embodiment, as shown in FIG. 1, the half aperture d of the maximum clear aperture of the object-side surface of the second lens corresponding to the maximum field angle of the optical lens and its corresponding value of Sg (rise) SAG satisfy arctan (SAG/d) ≦ 40, specifically, d and SAG may further satisfy arctan (SAG/d) ≦ 35, for example, 27.9 ≦ arctan (SAG/d) ≦ 31.8. The conditional expression arctan (SAG/d) is less than or equal to 40, the field angle of the image side surface of the second lens can be controlled within a certain range, and illumination is favorably improved; on the other hand, the light is facilitated to transit quickly.

In an exemplary embodiment, the optical lens third lens object side center radius of curvature R5 and the optical lens third lens image side center radius of curvature R6 satisfy-0.4. ltoreq. R5+ R6)/(R5-R6. ltoreq.0, specifically, R5 and R6 may further satisfy-0.35. ltoreq. R5+ R6)/(R5-R6. ltoreq. 0.15, for example, -0.26. ltoreq. R5+ R6)/(R5-R6. ltoreq. 0.22. Satisfying the conditional expression-0.4 ≦ (R5+ R6)/(R5-R6) ≦ 0, which can contribute to improving the molding processability of the third lens and the manufacturing yield.

In an exemplary embodiment, the total optical length TTL of the optical lens, the image height h corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy TTL/h/FOV ≦ 0.05, and specifically, TTL, h, and FOV may further satisfy TTL/h/FOV ≦ 0.04, for example, 0.03 ≦ TTL/h/FOV ≦ 0.04. The condition TTL/h/FOV is less than or equal to 0.05, which is beneficial to realizing the miniaturization of the optical lens.

In an exemplary embodiment, the fourth lens focal length F4 of the optical lens and the fifth lens focal length F5 of the optical lens satisfy | F4/F5| ≦ 5, and specifically, F4 and F5 may further satisfy | F4/F5| ≦ 4, for example, 1.08 ≦ | F4/F5| ≦ 1.13. The conditional expression of | F4/F5| is less than or equal to 5, so that the focal lengths of the fourth lens and the fifth lens are close to each other, and the light is smooth and excessive.

In an exemplary embodiment, the combined focal length F45 of the fourth and fifth lenses of the optical lens and the total effective focal length F of the optical lens satisfy F45/F ≦ 20, and in particular, F45 and F may further satisfy F45/F ≦ 17, e.g., 10.95 ≦ F45/F ≦ 12.58. The conditional expression F45/F is less than or equal to 20, the light direction between the third lens and the fifth lens can be controlled, the aberration caused by the large-angle light entering through the third lens is reduced, and meanwhile, the lens has a compact structure and is beneficial to the miniaturization of the optical lens.

In an exemplary embodiment, the maximum field angle FOV of the optical lens, the total effective focal length f of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens satisfy FOV f/h ≦ 80, and in particular, FOV, f, and h may further satisfy FOV f/h ≦ 70, e.g., 50.11 ≦ FOV f/h ≦ 50.66. The FOV f/h is less than or equal to 80, and the small distortion of the optical lens can be reduced.

In an exemplary embodiment, the lens used in the optical lens may be a plastic lens, or may be a glass lens. However, since the thermal expansion coefficient of the plastic lens is large, when the ambient temperature used by the lens changes greatly, the plastic lens causes a large amount of change in the optical back focus of the lens, and further causes problems such as a blurred out-of-focus image plane. The glass lens has a slightly higher cost, but the influence of temperature on the optical back focus of the lens can be obviously reduced.

Under the condition of not considering cost and manufacturing difficulty, the optical lens in the application can fully or partially adopt a glass aspheric lens so as to further improve the resolution power of the lens. In addition, in the case of not considering temperature stability or requiring low temperature stability, the optical lens of the present application may also fully or partially adopt a plastic aspheric lens, so as to further reduce the manufacturing cost of the lens.

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 above embodiment of the present application, by setting a reasonable lens shape and focal power, high resolution is achieved by using a 6-piece structure, and the requirements of small lens volume, low sensitivity and high production yield are taken into consideration. The optical lens of the embodiment has a small principal ray angle (CRA), can avoid stray light generated by the fact that the rear end of light rays is emitted to the lens barrel, can be matched with a vehicle-mounted chip, and cannot generate color cast and dark corner phenomena. The optical lens of the above embodiment has small distortion, and can realize that an imaging picture is not deformed basically. The optical lens of the embodiment has the advantages of large aperture, good imaging effect, high image quality reaching million high definition level, and capability of ensuring the definition of images in a low-light environment or at night.

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. 2. Fig. 2 shows a schematic structural diagram of an optical lens according to embodiment 1 of the present application.

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

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 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 power, and has a convex object-side surface S5 and a convex image-side surface S6.

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

The sixth lens element L6 has a negative power, and has a concave object-side surface S11 and a convex image-side surface S12. The object-side surface S11 and the image-side surface S12 of the sixth lens L6 include at least one inflection point.

Optionally, the optical lens may further include a filter L7 having an object side S13 and an image side S14, and an imaging plane IMA. Color filters may be used to correct for color deviations. Light from the object passes through each of the surfaces S1 to S14 in sequence and is finally imaged on the imaging plane IMA.

In this embodiment, the second lens L2, the third lens L3, and the sixth lens L6 are aspherical lenses.

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

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

TABLE 1

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	12.5680	1.0500	1.77	49.61
2	4.8850	2.5823
					3	54.1591	1.0835	1.59	61.12
4	12.8709	6.6707
					5	8.3337	3.1210	1.62	63.44
6	-13.0594	-0.3157
					STO	All-round	2.4000
8	10.9850	3.9540	1.61	60.61
					9	-4.3650	0.7960	1.76	26.61
10	50.9496	3.2627
					11	59.6860	1.9757	1.68	31.16
12	34.6088	0.1000
					13	All-round	0.5500	1.52	64.21
14	All-round	2.3944
					IMA	All-round

The present embodiment adopts six lenses as an example, and by reasonably distributing the focal power and the surface type of each lens, the center thickness of each lens and the air space between each lens, the lens can realize the effects of reducing the total optical length and expanding the field angle while ensuring a large imaging size and high pixels. 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 high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S5, S6, S11 and S12 in example 1.

TABLE 2

Flour mark

K

A

B

C

D

E

3

-524.5701

3.4343E-03

-1.6516E-04

8.4946E-06

-2.9253E-07

3.5516E-09

4

-33.6307

5.5561E-03

-2.8087E-04

1.7677E-05

-8.5129E-07

1.2996E-08

5

-1.0373

3.0069E-04

9.9062E-07

5.4400E-07

-3.5254E-08

1.5002E-09

6

5.8771

6.4240E-04

1.3419E-05

7.1080E-07

-4.5887E-08

2.8850E-09

11

240.2495

-5.4814E-03

1.6598E-04

-3.1846E-05

1.7625E-06

-2.0396E-08

12

52.2836

-4.5776E-03

1.3788E-04

-1.0135E-05

4.9181E-07

-6.9007E-09

Table 3 below gives the total optical length TTL (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface IMA) of the optical lens of example 1, the total effective focal length F of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum angle of view of the optical lens, the image height h corresponding to the maximum angle of view of the optical lens, the maximum angle of view FOV of the optical lens, the optical back focus (the distance from the center of the image-side of the last lens to the imaging surface of the optical lens) BFL of the optical lens, the focal length F4 of the fourth lens L4 of the optical lens, the focal length F5 of the fifth lens L5 of the optical lens, the combined focal length F45 of the fourth lens L4 and the fifth lens L5 of the optical lens, the central curvature radius R5 of the object-side surface S36 of the optical lens, and the central curvature radius R398938 of the image-side surface S3 of the third lens L6.

TABLE 3

Parameter(s)	TTL(mm)	f(mm)	D(mm)	h(mm)
					Numerical value	29.6247	6.1105	12.3048	10.0620
Parameter(s)	FOV(°)	BFL(mm)	F4(mm)	F5(mm)
					Numerical value	82.5200	3.0444	5.6295	-5.2035
Parameter(s)	F45(mm)	R5(mm)	R6(mm)
					Numerical value	76.8447	8.3337	-13.0594

In the present embodiment, the total optical length TTL of the optical lens and the total effective focal length f of the optical lens satisfy TTL/f equal to 4.85; the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens satisfy D/h/FOV of 0.01; the total optical length TTL of the optical lens and the optical back focus BFL of the optical lens meet the condition that BFL/TTL is 0.1; the half aperture d of the maximum light-passing aperture of the object-side surface S3 of the second lens L2 corresponding to the maximum field angle of the optical lens and the corresponding Sg (rise) value SAG satisfy arctan (SAG/d) of 31.8; the central curvature radius R5 of the object side S5 of the third optical lens L3 and the central curvature radius R6 of the image side S6 of the third lens L3 satisfy (R5+ R6)/(R5-R6) — 0.22; the total optical length TTL of the optical lens, the image height h corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens meet the condition that TTL/h/FOV is 0.04; a focal length F4 of the fourth lens L4 of the optical lens and a focal length F5 of the fifth lens L5 of the optical lens satisfy | F4/F5| ═ 1.08; the combined focal length F45 of the fourth lens L4 and the fifth lens L5 of the optical lens and the total effective focal length F of the optical lens satisfy F45/F-12.58; and the maximum field angle FOV of the optical lens, the total effective focal length f of the optical lens and the image height h corresponding to the maximum field angle of the optical lens meet the condition that FOV f/h is 50.11.

Example 2

An optical lens according to embodiment 2 of the present application is described below with reference to fig. 3. In this embodiment and the following embodiments, descriptions of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 3 shows a schematic structural diagram of an optical lens according to embodiment 2 of the present application.

An optical lens according to embodiment 2 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 2 of the present application.

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

Table 4 shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 2, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 5 below shows the conic coefficients k and high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S5, S6, S11 and S12 in example 2. Table 6 below gives the total optical length TTL (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface IMA) of the optical lens of example 2, the total effective focal length F of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum angle of view of the optical lens, the image height h corresponding to the maximum angle of view of the optical lens, the maximum angle of view FOV of the optical lens, the optical back focus BFL of the optical lens, the focal length F4 of the fourth lens L4 of the optical lens, the focal length F5 of the fifth lens L5 of the optical lens, the combined focal length F45 of the fourth lens L4 and the fifth lens L5 of the optical lens, the central curvature radius R5 of the object-side surface S5 of the third lens L3, and the central curvature radius R6 of the central curvature radius S6 of the third lens L3 of the optical lens L6. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

TABLE 4

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	13.2625	1.0197	1.77	49.61
2	4.8775	2.6527
					3	205.2617	0.9598	1.59	61.12
4	15.4406	6.4225
					5	8.2687	3.2642	1.62	63.44
6	-13.2893	-0.4168
					STO	All-round	2.6810
8	10.2352	3.8966	1.61	60.61
					9	-4.4365	0.9194	1.76	26.61
10	40.6660	3.0200
					11	-190.3233	2.1536	1.68	31.16
12	261.8768	0.1000
					13	All-round	0.5500	1.52	64.21
14	All-round	2.4926
					IMA	All-round

TABLE 5

Flour mark

K

A

B

C

D

E

3

-74.4900

3.5639E-03

-1.7093E-04

7.8765E-06

-3.1464E-07

4.6278E-09

4

-45.1648

5.6381E-03

-2.7961E-04

1.6365E-05

-9.5246E-07

1.9474E-08

5

-1.0596

2.9773E-04

9.5302E-07

5.0290E-07

-3.7637E-08

1.2918E-09

6

5.9833

6.0808E-04

1.3929E-05

7.0057E-07

-5.3738E-08

2.5660E-09

11

-24.8971

-5.2688E-03

1.8655E-04

-3.4484E-05

2.0966E-06

-3.0490E-08

12

-99.8211

-4.0528E-03

1.4961E-04

-9.7102E-06

4.2865E-07

-5.2663E-09

TABLE 6

Parameter(s)	TTL(mm)	f(mm)	D(mm)	h(mm)
					Numerical value	29.7153	6.1409	11.9118	9.9400
Parameter(s)	FOV(°)	BFL(mm)	F4(mm)	F5(mm)
					Numerical value	82.0000	3.1426	5.5966	-5.1637
Parameter(s)	F45(mm)	R5(mm)	R6(mm)
					Numerical value	67.2866	8.2687	-13.2893

In the present embodiment, the total optical length TTL of the optical lens and the total effective focal length f of the optical lens satisfy TTL/f equal to 4.84; the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens satisfy D/h/FOV of 0.01; the total optical length TTL of the optical lens and the optical back focus BFL of the optical lens meet the condition that BFL/TTL is 0.11; the half aperture d of the maximum light-passing aperture of the object-side surface S3 of the second lens L2 corresponding to the maximum field angle of the optical lens and the corresponding Sg value SAG satisfy arctan (SAG/d) 27.9; the central curvature radius R5 of the object side S5 of the third optical lens L3 and the central curvature radius R6 of the image side S6 of the third lens L3 satisfy (R5+ R6)/(R5-R6) — 0.23; the total optical length TTL of the optical lens, the image height h corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens meet the condition that TTL/h/FOV is 0.04; a focal length F4 of the fourth lens L4 of the optical lens and a focal length F5 of the fifth lens L5 of the optical lens satisfy | F4/F5| ═ 1.08; the combined focal length F45 of the fourth lens L4 and the fifth lens L5 of the optical lens and the total effective focal length F of the optical lens satisfy F45/F-10.96; and the maximum field angle FOV of the optical lens, the total effective focal length f of the optical lens and the image height h corresponding to the maximum field angle of the optical lens meet the condition that FOV f/h is 50.66.

Example 3

An optical lens according to embodiment 3 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 3 of the present application.

As shown in fig. 4, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6.

Table 7 shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 3, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 8 below shows the conic coefficients k and high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S5, S6, S11 and S12 in example 3. Table 9 below gives the total optical length TTL (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface IMA) of the optical lens of example 3, the total effective focal length F of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum angle of view of the optical lens, the image height h corresponding to the maximum angle of view of the optical lens, the maximum angle of view FOV of the optical lens, the optical back focus BFL of the optical lens, the focal length F4 of the fourth lens L4 of the optical lens, the focal length F5 of the fifth lens L5 of the optical lens, the combined focal length F45 of the fourth lens L4 and the fifth lens L5 of the optical lens, the central curvature radius R5 of the object-side surface S5 of the third lens L3, and the central curvature radius R6 of the central curvature radius S6 of the third lens L3 of the optical lens L6. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

TABLE 7

TABLE 8

Flour mark

K

A

B

C

D

E

3

54.7616

3.8498E-03

-1.6621E-04

7.8336E-06

-3.2734E-07

4.6270E-09

4

-65.3611

5.7890E-03

-2.6773E-04

1.6156E-05

-9.7878E-07

1.9800E-08

5

-1.0736

2.9540E-04

9.3264E-07

4.7252E-07

-4.0772E-08

1.2443E-09

6

6.2700

5.5445E-04

1.1847E-05

6.9825E-07

-5.4288E-08

2.0890E-09

11

99.9980

-5.0418E-03

1.9036E-04

-3.7162E-05

2.2076E-06

-3.1254E-08

12

87.9690

-3.4711E-03

1.3801E-04

-9.5516E-06

4.3873E-07

-6.4953E-09

TABLE 9

Parameter(s)	TTL(mm)	f(mm)	D(mm)	h(mm)
					Numerical value	29.6932	6.2214	12.0023	10.1000
Parameter(s)	FOV(°)	BFL(mm)	F4(mm)	F5(mm)
					Numerical value	82.0000	3.1344	5.4118	-4.8010
Parameter(s)	F45(mm)	R5(mm)	R6(mm)
					Numerical value	75.3933	8.2050	-13.8815

In the present embodiment, the total optical length TTL of the optical lens and the total effective focal length f of the optical lens satisfy TTL/f equal to 4.77; the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens, and the image height h corresponding to the maximum field angle of the optical lens satisfy D/h/FOV of 0.01; the total optical length TTL of the optical lens and the optical back focus BFL of the optical lens meet the condition that BFL/TTL is 0.11; the half aperture d of the maximum light-passing aperture of the object-side surface S3 of the second lens L2 corresponding to the maximum field angle of the optical lens and the corresponding Sg value SAG satisfy arctan (SAG/d) of 28.66; the central curvature radius R5 of the object side S5 of the third optical lens L3 and the central curvature radius R6 of the image side S6 of the third lens L3 satisfy (R5+ R6)/(R5-R6) — 0.26; the total optical length TTL of the optical lens, the image height h corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens meet the condition that TTL/h/FOV is 0.04; a focal length F4 of the fourth lens L4 of the optical lens and a focal length F5 of the fifth lens L5 of the optical lens satisfy | F4/F5| ═ 1.13; the combined focal length F45 of the fourth lens L4 and the fifth lens L5 of the optical lens and the total effective focal length F of the optical lens satisfy F45/F-12.12; and the maximum field angle FOV of the optical lens, the total effective focal length f of the optical lens and the image height h corresponding to the maximum field angle of the optical lens meet the condition that FOV f/h is 50.51.

In summary, examples 1 to 3 each satisfy the relationship shown in table 10 below.

Watch 10

Conditional expression (A) example	E1	E2	E3
				TTL/F	4.85	4.84	4.77
D/h/FOV	0.01	0.01	0.01
				0.05≤BFL/TTL	0.1	0.11	0.11
arctan(SAG/d)	31.8	27.9	28.66
				(R5+R6)/(R5-R6)	-0.22	-0.23	-0.26
TTL/h/FOV	0.04	0.04	0.04
				\|F4/F5\|	1.08	1.08	1.13
F45/F	12.58	10.96	12.12
				FOV*F/H	50.11	50.66	50.51

The present application also provides an imaging apparatus that may include the optical lens according to the above-described embodiment of the present application and an imaging element for converting an optical image formed by the optical lens into an electrical signal. The imaging element may be a photo-coupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device may be a stand-alone imaging device such as a range finding camera or may be an imaging module integrated on a device such as a range finding device.

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, wherein the number of lenses having refractive power is six, and the lenses are respectively a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, 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 convex surface, and the image side surface of the first lens is a concave surface;

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

the fourth lens has 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; and

the sixth lens has a negative optical power; and

the optical lens satisfies that FOV f/h is less than or equal to 80 degrees,

wherein the FOV is the maximum field angle of the optical lens;

f is the total effective focal length of the optical lens; and

h is the image height corresponding to the maximum field angle of the optical lens.

2. An optical lens barrel according to claim 1, wherein the sixth lens element has a concave object-side surface and a convex image-side surface.

3. An optical lens barrel according to claim 1, wherein the object side surface and the image side surface of the sixth lens respectively include at least one inflection point.

4. An optical lens barrel according to claim 1, wherein the fourth lens element and the fifth lens element are double cemented lens elements, and the double cemented lens elements are formed by connecting an image side surface of the fourth lens element and an object side surface of the fifth lens element with each other by a cement material.

5. An optical lens according to claim 1, wherein at least two lenses among the first lens to the sixth lens are aspherical lenses.

6. An optical lens according to claim 1, characterized in that the second lens, the third lens and the sixth lens are aspherical lenses.

7. An optical lens according to claim 1, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all made of glass.

8. An optical lens according to claim 1, characterized in that the optical lens further comprises a diaphragm disposed between the third lens and the fourth lens.

9. An optical lens according to any one of claims 1 to 7, wherein an overall optical length TTL of the optical lens and an overall effective focal length f of the optical lens satisfy TTL/f ≦ 6.5.

10. An optical lens according to any of claims 1 to 7, characterized in that (D180 °/(h FOV) ≦ 9.00 is satisfied,

the FOV is the maximum field angle of the optical lens;

d is the maximum light-passing aperture of the object side surface of the first lens corresponding to the maximum field angle of the optical lens; and

11. An optical lens according to any one of claims 1 to 7, characterized in that the total optical length TTL of the optical lens and the optical back focus BFL of the optical lens satisfy 0.03 ≦ BFL/TTL ≦ 0.3.

12. An optical lens according to any one of claims 1 to 7, characterized in that the half aperture d of the maximum clear aperture of the object-side surface of the second lens corresponding to the maximum field angle of the optical lens and the corresponding Sg value SAG satisfy arctan (SAG/d) ≦ 40.

13. An optical lens according to any one of claims 1 to 7, characterized in that a center radius of curvature R5 of an object side center of the optical lens third lens and a center radius of curvature R6 of an image side center of the optical lens third lens satisfy-0.4 ≦ (R5+ R6)/(R5-R6) ≦ 0.

14. An optical lens element according to any of claims 1 to 7, characterized in that (TTL 180 °/(hFOV) ≦ 9.00,

TTL is the total optical length of the optical lens;

h is the image height corresponding to the maximum field angle of the optical lens; and

the FOV is the maximum field angle of the optical lens.

15. An optical lens according to any one of claims 1 to 7, characterized in that the fourth lens focal length F4 of the optical lens and the fifth lens focal length F5 of the optical lens satisfy | F4/F5| ≦ 5.

16. An optical lens according to any one of claims 1 to 7, characterized in that a combined focal length F45 of the fourth and fifth lenses of the optical lens and a total effective focal length F of the optical lens satisfy F45/F ≦ 20.

17. An optical lens, wherein the number of lenses having refractive power is six, and the lenses are respectively a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, 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 and the second lens each have a negative optical power;

the third lens and the fourth lens each have positive optical power;

the fifth lens and the sixth lens each have a negative optical power;

the fourth lens and the fifth lens are mutually glued to form a double-glued lens; and

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 6.5;

the maximum field angle FOV of the optical lens, the total effective focal length f of the optical lens and the image height h corresponding to the maximum field angle of the optical lens meet the condition that FOV f/h is less than or equal to 80 degrees.

18. An optical lens barrel according to claim 17, wherein the first lens element has a convex object-side surface and a concave image-side surface.

19. An optical lens barrel according to claim 17, wherein the second lens element has a convex object-side surface and a concave image-side surface.

20. An optical lens barrel according to claim 17, wherein the object side surface and the image side surface of the third lens are convex.

21. An optical lens barrel according to claim 17, wherein the object side surface and the image side surface of the fourth lens are convex.

22. An optical lens barrel according to claim 17, wherein the fifth lens element has concave object and image side surfaces.

23. An optical lens barrel according to claim 17, wherein the sixth lens element has a concave object-side surface and a convex image-side surface.

24. An optical lens barrel according to claim 17, wherein the object side surface and the image side surface of the sixth lens respectively include at least one inflection point.

25. An optical lens barrel according to claim 17, wherein at least two lenses among the first lens to the sixth lens are aspherical lenses.

26. An optical lens according to claim 17, wherein the second lens, the third lens and the sixth lens are aspherical lenses.

27. An optical lens barrel according to claim 17, wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all made of glass.

28. An optical lens according to claim 17, characterized in that the optical lens further comprises a diaphragm disposed between the third lens and the fourth lens.

29. An optical lens element according to any of claims 17 to 28, characterized in that (D180 °/(h FOV) ≦ 9.00,

the FOV is the maximum field angle of the optical lens;

30. An optical lens according to any one of claims 17 to 28, characterized in that an overall optical length TTL of the optical lens and an optical back focus BFL of the optical lens satisfy 0.03 ≦ BFL/TTL ≦ 0.3.

31. An optical lens element according to any one of claims 17 to 28, wherein the half aperture d of the maximum clear aperture of the object-side surface of the second lens element corresponding to the maximum field angle of the optical lens element and the Sg value SAG corresponding thereto satisfy arctan (SAG/d) ≦ 40.

32. An optical lens according to any one of claims 17 to 28, characterized in that the optical lens third lens object side center radius of curvature R5 and the optical lens third lens image side center radius of curvature R6 satisfy-0.4 ≦ (R5+ R6)/(R5-R6) ≦ 0.

33. An optical lens element according to any of claims 17 to 28, characterized in that (TTL 180 °/(hFOV) ≦ 9.00,

TTL is the total optical length of the optical lens;

the FOV is the maximum field angle of the optical lens.

34. An optical lens according to any one of claims 17 to 28, characterized in that the fourth lens focal length F4 of the optical lens and the fifth lens focal length F5 of the optical lens satisfy | F4/F5| ≦ 5.

35. An optical lens according to any one of claims 17 to 28, characterized in that the combined focal length F45 of the fourth and fifth lenses of the optical lens and the total effective focal length F of the optical lens satisfy F45/F ≦ 20.

36. An imaging apparatus comprising the optical lens of claim 1 or 17 and an imaging element for converting an optical image formed by the optical lens into an electric signal.