CN110794551A

CN110794551A - Optical lens

Info

Publication number: CN110794551A
Application number: CN201810861955.4A
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: 2018-08-01
Filing date: 2018-08-01
Publication date: 2020-02-14
Anticipated expiration: 2038-08-01
Also published as: CN110794551B

Abstract

The present application discloses an optical lens, which sequentially comprises, from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. Wherein the first lens may have a negative optical power; the object side surface is a convex surface, and the image side surface is a concave surface; the second lens can have negative focal power, and both the object side surface and the image side surface of the second lens are concave; the third lens can have positive focal power, and both the object side surface and the image side surface of the third lens are convex surfaces; the fourth lens can have positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces; the fifth lens element may have a negative focal power, and both the object-side surface and the image-side surface thereof may be concave; and the sixth lens element may have a positive optical power, and both the object-side surface and the image-side surface thereof are convex. According to the optical lens disclosed by the application, at least one of the beneficial effects of miniaturization, small front-end caliber, high resolution, large aperture, small CRA, low cost, rear focal length and the like can be realized.

Description

Optical lens

Technical Field

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

Background

Owing to the rapid development of automobile driving-assisting systems in recent years, lenses are increasingly widely applied to automobiles, and the pixel requirements of vehicle-mounted lenses are also increasingly higher. At the same time more and more companies are beginning to study the autopilot lens.

For safety reasons, the performance requirements of optical lenses for vehicle-mounted applications are usually very high, while those for automatic driving are more stringent. Firstly, the autopilot lens requires extremely high pixel requirements, and on the basis of the original vehicle-mounted optical lens, the optical lens applied to autopilot can adopt 6, 7 or even more lens structures in order to improve the resolution capability, but the miniaturization of the lens can be seriously influenced. Meanwhile, such optical lenses require a larger aperture to realize clear recognition of a low-light environment. In addition, the requirements of such optical lenses on stray light are particularly high, and a smaller CRA is required to avoid the stray light generated when the rear end of the light ray is emitted and hits on the lens barrel.

Therefore, an optical lens with high resolution and small size and low cost, which can be used in low light environment, is needed to meet the requirements of automatic driving application.

Disclosure of Invention

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

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

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

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

In one embodiment, at least one of the first lens and the sixth lens may be an aspherical mirror.

In one embodiment, the total optical length TTL of the optical lens and the entire focal length F of the optical lens may satisfy: TTL/F is less than or equal to 5.

In one embodiment, the optical back focus BFL of the optical lens and the lens group length TL of the optical lens may satisfy: BFL/TL is more than or equal to 0.25.

In one embodiment, the air space d5 between the third lens and the fourth lens and the total optical length TTL of the optical lens may satisfy: d5/TTL is more than or equal to 0.008.

In one embodiment, the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens may satisfy: D/H/FOV is less than or equal to 0.025.

In one embodiment, the focal length value F3 of the third lens and the focal length value F2 of the second lens satisfy: the ratio of F3 to F2 is less than or equal to 1.5.

In one embodiment, the combined focal length value F23 of the first lens and the second lens and the entire set of focal length values F of the optical lens may satisfy: F23/F is more than or equal to 1.5 and less than or equal to 4.

In one embodiment, a center radius of curvature R2 of the image side surface of the first lens and a center radius of curvature R3 of the object side surface of the second lens may satisfy: the ratio of (R2-R3)/(R2+ R3) is less than or equal to-6 and less than or equal to-0.8.

Another aspect of the present application provides an optical lens that may include, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens, the second lens and the fifth lens can all have negative focal power; the third lens, the fourth lens and the sixth lens may each have positive optical power; the second lens and the third lens can be mutually glued to form a first cemented lens; the fourth lens, the fifth lens and the sixth lens can be cemented to form a second cemented lens; and the optical back focus BFL of the optical lens and the lens group length TL of the optical lens can meet the following requirements: BFL/TL is more than or equal to 0.25.

In one embodiment, the object-side surface of the first lens element can be convex and the image-side surface can be concave.

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

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

In one embodiment, both the object-side surface and the image-side surface of the fourth lens can be convex.

In one embodiment, both the object-side surface and the image-side surface of the fifth lens may be concave.

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

In one embodiment, the combined focal length value F23 of the second lens and the third lens and the entire set of focal length values F of the optical lens may satisfy: F23/F is more than or equal to 1.5 and less than or equal to 4.

The optical lens adopts six lenses, the focal power of each lens is reasonably distributed and the cemented lens is formed by optimally setting the shape of the lens, so that at least one of the beneficial effects of miniaturization, small front-end caliber, high resolution, large aperture, small CRA (crap-crap), low cost, back focal length and the like of the optical lens is realized.

Drawings

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

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

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

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

Detailed Description

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

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

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

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

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

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

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

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

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

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

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

The second lens can have a negative optical power, and both the object-side surface and the image-side surface can be concave.

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

In an exemplary embodiment, a diaphragm for limiting the light beam may be disposed between, for example, the third lens and the fourth lens to further improve the imaging quality of the lens. When the diaphragm is arranged between the third lens and the fourth lens, light rays entering the optical system can be effectively converged, and the aperture of the lens of the optical system is reduced. It should be noted, however, that the positions of the diaphragms disclosed herein are merely examples and not limitations; in alternative embodiments, the diaphragm may be disposed at other positions according to actual needs.

In an exemplary embodiment, the fourth lens may have a positive focal power, and after the aperture stop is disposed, one fourth lens having a positive focal power is used, so that aberration generated by the front lens group can be further corrected, and the light beams are converged again, so that the aperture of the lens can be increased, the total length of the lens can be shortened, and the optical system can be more compact, so that the optical system has a relatively short total length of the lens.

In an exemplary embodiment, the optical lens according to the present application may further include a filter disposed between the sixth lens and the imaging surface to filter light rays having different wavelengths, as necessary; and may further include a protective glass disposed between the optical filter and the imaging surface to prevent internal elements (e.g., chips) of the optical lens from being damaged.

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

In an exemplary embodiment, the second lens and the third lens may be combined into the first cemented lens by cementing the image-side surface of the second lens with the object-side surface of the third lens. The first cemented lens is composed of a positive lens (i.e., the third lens) and a negative lens (i.e., the second lens). The positive lens has a high refractive index, the negative lens has a low refractive index (relative to the positive lens), and the matching of the high refractive index and the low refractive index is beneficial to the rapid transition of the front light, the aperture of the diaphragm is increased, and the night vision requirement is met. In addition, the adoption of the first cemented lens effectively reduces the chromatic aberration of the system, enables the whole structure of the optical system to be compact, meets the miniaturization requirement, and simultaneously reduces the tolerance sensitivity problems of inclination/decentration and the like generated in the assembling process of the lens unit. If the discrete lens is located at the turning position of the light, the sensitivity is easily caused by processing/assembling errors, so the arrangement of the cemented lens group effectively reduces the sensitivity.

In the first cemented lens, the second lens close to the object side has negative focal power, the third lens close to the image side has positive focal power, the negative film is arranged in front, and the positive film is arranged at the back, so that the front light can be dispersed, rapidly converged and then transited to the back, the optical path of the back light can be reduced, and the short TTL can be realized.

In an exemplary embodiment, the fourth lens, the fifth lens and the sixth lens can be combined into a second cemented lens by cementing the image side surface of the fourth lens with the object side surface of the fifth lens and cementing the image side surface of the fifth lens with the object side surface of the sixth lens, the second cemented lens is a triple cemented lens, and the adoption of the triple cemented lens has the advantages that ① reduces the air space between the three lenses and the total length of the system, ② reduces the assembly components between the three lenses, reduces the procedures and the cost, ③ reduces tolerance sensitivity problems of inclination/decentration and the like of the lens units generated in the assembly process, ④ reduces the light quantity loss caused by reflection between the lenses and improves the illumination, and ⑤ can further reduce the field curvature and can correct the off-axis point aberration of the system.

The use of the first cemented lens and the second cemented lens shares the whole chromatic aberration correction of the system, can effectively correct aberration, improves the resolving power, makes the optical system compact as a whole, and meets the miniaturization requirement.

In an exemplary embodiment, an optical total length TTL of the optical lens and a whole set of focal length values F of the optical lens may satisfy: TTL/F is less than or equal to 5, and more ideally, TTL/F is less than or equal to 4.5. The condition formula TTL/F is less than or equal to 5, and the miniaturization characteristic of the system can be ensured.

In an exemplary embodiment, the optical back focus BFL of the optical lens and the lens group length TL of the optical lens may satisfy: the BFL/TL ratio is more than or equal to 0.25, and more ideally, the BFL/TL ratio is more than or equal to 0.35. By satisfying the condition that BFL/TL is more than or equal to 0.25, the back focal length can be realized on the basis of realizing miniaturization, thereby being beneficial to the assembly of the module. On the other hand, the lens group has short length TL and compact structure, can reduce the sensitivity of the lens to MTF, improve the production yield and reduce the production cost.

In an exemplary embodiment, an air interval d5 between the third lens and the fourth lens and an optical total length TTL of the optical lens may satisfy: d5/TTL is not less than 0.008, more preferably, d5/TTL is not less than 0.01. The condition that d5/TTL is more than or equal to 0.008 is met, so that the center distance between two groups of adjacent cemented lenses is large, light rays near the diaphragm are in smooth transition, and the image quality of the system is improved.

In an exemplary embodiment, the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens may satisfy: D/H/FOV is 0.025 or less, and more preferably, D/H/FOV is 0.02 or less. Satisfies the conditional expression D/H/FOV less than or equal to 0.025, and can realize the characteristics of small caliber and miniaturization at the front end of the lens.

In an exemplary embodiment, a focal length value F3 of the third lens and a focal length value F2 of the second lens may satisfy: the | F3/F2| is less than or equal to 1.5, and more ideally, the | F3/F2| is less than or equal to 1.2. The ratio of the absolute value of F3/F2 is less than or equal to 1.5 by satisfying the conditional expression. The focal length of two adjacent lenses can be close, and light can be smoothly transited.

In an exemplary embodiment, a combined focal length value F23 of the second lens and the third lens and a full set focal length value F of the optical lens may satisfy: F23/F is 1.5. ltoreq. F23/F.ltoreq.4, and more preferably 1.8. ltoreq. F23/F.ltoreq.3.9. By satisfying the conditional expression that F23/F is more than or equal to 1.5 and less than or equal to 4, the light trend between the first lens and the fourth lens can be controlled, the aberration caused by large-angle light entering through the first lens is reduced, and meanwhile, the structure of the lens is compact, which is beneficial to realizing miniaturization.

In an exemplary embodiment, a center radius of curvature R2 of the image side surface of the first lens and a center radius of curvature R3 of the object side surface of the second lens may satisfy: (R2-R3)/(R2+ R3) is not more than-6 and not more than-0.8, more preferably not more than-5.5 (R2-R3)/(R2+ R3) is not more than-1.3. By satisfying the conditional expression: 6 ≦ (R2-R3)/(R2+ R3) ≦ -0.8 for correcting aberration of the optical system and ensuring that the incident angle is not too large when the light exiting from the first lens is incident on the first face of the second lens, thereby decreasing tolerance sensitivity of the optical system, and if the upper limit value is exceeded, the aberration of the optical system cannot be sufficiently corrected; if the light beam is less than the lower limit value, the incident angle of the light beam emitted from the first lens when the light beam enters the first surface of the second lens is too large, which increases the sensitivity of the optical system.

In an exemplary embodiment, at least one of the first lens and the sixth lens in the optical lens according to the present application may employ an aspherical mirror. The aspheric lens has the characteristics that: the curvature varies continuously from the center of the lens to the periphery. Unlike a spherical lens having a constant curvature from the center to the periphery of the lens, an aspherical lens has better curvature radius characteristics, and has the advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated in imaging can be eliminated as much as possible, so that the imaging quality of the lens is improved. For example, the first lens may be an aspheric lens to reduce aberration, which helps to further improve the resolution quality. The sixth lens can be an aspheric lens so as to smoothly transfer the light rays passing through the fifth lens to an imaging surface and reduce the total length of the system; various aberrations of the optical system are fully corrected, and on the premise of compact structure, the resolution can be improved, and optical performances such as distortion, CRA and the like can be optimized. Ideally, the first lens and the sixth lens are both aspheric lenses, which is helpful for further improving the imaging quality of the lens. It should be understood that, in order to improve the imaging quality, the optical lens according to the present application may increase the number of aspheric lenses, for example, in the case where the resolution quality is focused, the aspheric lenses may be used for the first to sixth lenses.

In an exemplary embodiment, the lens used in the optical lens may be a plastic lens, or may be a glass lens. The lens made of plastic has a large thermal expansion coefficient, and when the ambient temperature change of the lens is large, the lens made of plastic causes a large amount of change of the optical back focus of the lens. The glass lens can reduce the influence of temperature on the optical back focus of the lens, but has higher cost.

According to the optical lens of the above embodiment of the present application, through reasonable lens shape setting and optical power setting, high resolution can be achieved only by using 6-piece structure, and meanwhile, the requirements of small lens volume, low sensitivity and high production yield and low cost can be met. In addition, the optical lens CRA according to the embodiment of the application is small, so that the condition that stray light is generated when the rear end of light rays is emitted to a lens barrel is avoided, the optical lens CRA can be well matched with a vehicle-mounted chip, and the phenomena of color cast and dark corners cannot be generated; possess big light ring, the formation of image effect is good, and image quality reaches high definition level, even when in low light environment or night, also can guarantee the definition of image. Therefore, the optical lens according to the above-described embodiment of the present application can have at least one of the advantages of miniaturization, a small front end aperture, high resolution, a large aperture, a small CRA, low cost, a long back focal length, and the like, and can better meet the requirements of an in-vehicle lens.

It will be understood by those skilled in the art that the total optical length TTL of the optical lens used above refers to the on-axis distance from the center of the object-side surface of the first lens to the center of the imaging surface; the optical back focus BFL of the optical lens refers to the axial distance from the center of the image side surface of the sixth lens of the last lens to the center of the imaging surface; and the lens group length TL of the optical lens means an on-axis distance from the center of the object-side surface of the first lens to the center of the image-side surface of the sixth lens.

It will be understood by those skilled in the art that the number of lenses making up the lens barrel may be varied to achieve the various results and advantages described in this specification without departing from the claimed subject matter. For example, although six lenses are exemplified in the embodiment, the optical lens is not limited to including six lenses. The optical lens may also include other numbers of lenses, if desired.

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

Example 1

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

As shown in fig. 1, the optical lens includes, in order from 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 biconcave lens with negative optical power, and both the object-side surface S3 and the image-side surface S4 are concave. The third lens L3 is a biconvex lens with positive optical power, and has concave object-side surface S4 and concave image-side surface S5. The second lens L2 and the third lens L3 are cemented with each other to form a first cemented lens.

The fourth lens L4 is a biconvex lens with positive optical power, and has both the object-side surface S7 and the image-side surface S8 convex. The fifth lens L5 is a biconcave lens with negative optical power, and both the object-side surface S8 and the image-side surface S9 are concave. The sixth lens L6 is a biconvex lens with positive optical power, and has both the object-side surface S9 and the image-side surface S10 convex. Wherein the fourth lens L4, the fifth lens L5, and the sixth lens L6 are cemented to form a second cemented lens.

The first lens element L1 and the sixth lens element L6 are both aspheric lenses, the object-side surface S1 and the image-side surface S2 of the first lens element L1 are both aspheric, and the image-side surface S10 of the sixth lens element L6 is aspheric.

Optionally, the optical lens may further include a filter L7 having an object-side surface S11 and an image-side surface S12 and/or a protective lens L8 having an object-side surface S13 and an image-side surface S14. Filter L7 can be used to correct for color deviations. The protective lens L8 may be used to protect the image sensing chip on the imaging plane IMA. 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 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 first cemented lens and the second 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	15.4577	1.0000	1.59	61.16
2	4.9780	4.2847
					3	-10.2519	4.0321	1.52	52.19
4	9.3613	2.9851	1.74	44.90
					5	-12.3710	0.1000
STO	All-round	0.6000
					7	8.2627	3.6760	1.62	63.41
8	-17.4453	0.7500	1.76	27.55
					9	7.8568	3.2405	1.62	63.40
10	-28.8874	2.0168
					11	All-round	0.5500	1.52	64.21
12	All-round	6.2221
					13	All-round	0.4000	1.52	64.21
14	All-round	0.1250
					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 have at least one of the advantages of miniaturization, small front end aperture, high resolution, large aperture, small CRA, low cost, long back focal length, and the like. 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 the aspherical lens surfaces S1, S2, and S10 in example 1.

TABLE 2

Flour mark

K

A

B

C

D

E

1

4.9627

-2.5829E-04

3.5087E-07

-1.9316E-07

7.3555E-09

-1.9810E-10

2

-0.2402

6.2445E-05

3.2719E-05

-3.2019E-06

2.6906E-07

-5.0352E-09

10

-118.6130

2.5325E-04

3.4354E-05

-6.1359E-07

5.4959E-09

2.4208E-10

Table 3 below gives the entire group focal length value F of the optical lens of example 1, the focal length values F2-F3 of the second lens L2 and the third lens L3, 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 focal length value F23 of the first cemented lens (formed by the second lens and the third lens cemented together), the total optical length TTL of the optical lens (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), the central radius of curvature R2 of the image-side surface S2 of the first lens L1, the central radius of curvature R3 of the object-side surface S3 of the second lens L2, the optical back focus BFL of the optical lens (i.e., the on-axis distance from the center of the imaging surface S38 of the image-side surface S6 of the last lens L6 to the imaging surface IMA), A lens group length TL of the optical lens (i.e., an on-axis distance from the center of the object side surface S1 of the first lens L1 to the image side surface S10 of the sixth lens L6 of the optical lens) and an air interval d5 between the third lens L3 and the fourth lens L4.

TABLE 3

F2(mm)	-8.7999	TTL(mm)	29.9823
				F3(mm)	7.5737	R2(mm)	4.9780
D(mm)	11.7523	R3(mm)	-10.2519
				H(mm)	10.868	BFL(mm)	9.3139
FOV(°)	84	TL(mm)	20.6684
				F23(mm)	20.884	d5(mm)	0.7000
F(mm)	7.2633

In the present embodiment, BFL/TL is 0.4506 between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens; d5/TTL 0.0233 is satisfied between an air interval d5 between the third lens L3 and the fourth lens L4 and an optical total length TTL of the optical lens; 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 that D/H/FOV is 0.0129; a focal length value F3 of the third lens L3 and a focal length value F2 of the second lens L2 satisfy | F3/F2| ═ 0.8607; F23/F2.8753 is satisfied between the focal length value F23 of the first cemented lens and the focal length value F of the entire group of the optical lens; a central curvature radius R2 of the image-side surface S2 of the first lens L1 and a central curvature radius R3 of the object-side surface S3 of the second lens L2 satisfy (R2-R3)/(R2+ R3) — 2.8878; and the total optical length TTL of the optical lens and the whole group focal length value F of the optical lens satisfy that the TTL/F is 4.1279.

Example 2

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

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

Table 4 below shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 2, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 5 below shows the conic coefficients k and the high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S1, S2, and S10 in example 2. Table 6 below gives the entire group focal length value F of the optical lens of example 2, the focal length values F2 to F3 of the second lens L2 and the third lens L3, 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 focal length value F23 of the first cemented lens, the optical total length TTL of the optical lens, the center radius of curvature R2 of the image-side surface S2 of the first lens L1, the center radius of curvature R3 of the object-side surface S3 of the second lens L2, the optical back focus BFL of the optical lens, the lens group length TL of the optical lens, and the air space D5 between the third lens L3 and the fourth lens L4.

TABLE 4

TABLE 5

Flour mark

K

A

B

C

D

E

1

7.1367

-4.6675E-04

-1.4183E-05

-5.0141E-08

2.1001E-08

-8.2093E-10

2

-0.3841

8.8227E-04

7.2599E-05

-1.0415E-05

1.0514E-06

-2.4856E-08

10

-85.3204

-5.7677E-04

9.7595E-05

-4.7762E-06

1.6594E-07

-2.4187E-09

TABLE 6

F2(mm)	-7.5275	TTL(mm)	27.8827
				F3(mm)	6.8457	R2(mm)	4.9146
D(mm)	9.7863	R3(mm)	-8.0274
				H(mm)	10.016	BFL(mm)	9.2598
FOV(°)	86	TL(mm)	18.6229
				F23(mm)	21.2311	d5(mm)	0.7024
F(mm)	7.2650

In the present embodiment, BFL/TL is 0.4972 between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens; d5/TTL 0.0252 is satisfied between an air interval d5 between the third lens L3 and the fourth lens L4 and an optical total length TTL of the optical lens; the maximum field angle FOV of the optical lens, the maximum light-transmitting 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 0.0114; a focal length value F3 of the third lens L3 and a focal length value F2 of the second lens L2 satisfy | F3/F2| ═ 0.9094; F23/F2.9224 is satisfied between the focal length value F23 of the first cemented lens and the focal length value F of the entire group of the optical lens; a central curvature radius R2 of the image-side surface S2 of the first lens L1 and a central curvature radius R3 of the object-side surface S3 of the second lens L2 satisfy (R2-R3)/(R2+ R3) — 4.1577; and the total optical length TTL of the optical lens and the whole group focal length value F of the optical lens satisfy that the TTL/F is 3.8379.

Example 3

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

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

Table 7 below shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 3, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 8 below shows the conic coefficients k and the high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S1, S2, and S10 in example 3. Table 9 below gives the entire group focal length value F of the optical lens of example 3, the focal length values F2 to F3 of the second lens L2 and the third lens L3, 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 focal length value F23 of the first cemented lens, the optical total length TTL of the optical lens, the central curvature radius R2 of the image-side surface S2 of the first lens L1, the central curvature radius R3 of the object-side surface S3 of the second lens L2, the optical back focus BFL of the optical lens, the lens group length TL of the optical lens, and the air interval D5 between the third lens L3 and the fourth lens L4.

TABLE 7

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	16.4358	0.9977	1.59	61.16
2	4.8750	3.5105
					3	-7.9675	2.9279	1.52	52.19
4	8.5074	3.1103	1.74	44.90
					5	-10.6941	-0.3201
STO	All-round	0.8661
					7	8.2621	3.5778	1.62	63.41
8	-12.3963	0.7764	1.76	27.55
					9	9.2708	3.2158	1.62	63.40
10	-20.7526	2.0000
					11	All-round	0.5500	1.52	64.21
12	All-round	6.3297
					13	All-round	0.4000	1.52	64.21
14	All-round	0.1250
					IMA	All-round

TABLE 8

Flour mark

K

A

B

C

D

E

1

7.0847

-4.9033E-04

-1.2791E-05

-5.3788E-08

2.0675E-08

-7.4137E-10

2

-0.3774

9.0965E-04

6.8031E-05

-1.0307E-05

1.0845E-06

-2.4985E-08

10

-91.8187

-5.5307E-04

9.6961E-05

-4.8178E-06

1.6903E-07

-2.5314E-09

TABLE 9

F2(mm)	-7.4656	TTL(mm)	28.0671
				F3(mm)	6.8102	R2(mm)	4.8750
D(mm)	9.6505	R3(mm)	-7.9675
				H(mm)	10.02	BFL(mm)	9.4047
FOV(°)	86	TL(mm)	18.6624
				F23(mm)	20.8318	d5(mm)	0.5460
F(mm)	7.2830

In the present embodiment, BFL/TL is 0.5039 between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens; an air interval d5 between the third lens L3 and the fourth lens L4 and an optical total length TTL of the optical lens satisfy that d5/TTL is 0.0195; the maximum field angle FOV of the optical lens, the maximum light-transmitting 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 0.0112; a focal length value F3 of the third lens L3 and a focal length value F2 of the second lens L2 satisfy | F3/F2| ═ 0.9122; F23/F2.8603 is satisfied between the focal length value F23 of the first cemented lens and the focal length value F of the entire group of the optical lens; a central curvature radius R2 of the image-side surface S2 of the first lens L1 and a central curvature radius R3 of the object-side surface S3 of the second lens L2 satisfy (R2-R3)/(R2+ R3) — 4.1528; and the total optical length TTL of the optical lens and the whole group focal length value F of the optical lens satisfy that the TTL/F is 3.8538.

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

Watch 10

Conditions/examples	1	2	3
				BFL/TL	0.4506	0.4972	0.5039
d5/TTL	0.0233	0.0252	0.0195
				D/H/FOV	0.0129	0.0114	0.0112
\|F3/F2\|	0.8607	0.9094	0.9122
				F23/F	2.8753	2.9224	2.8603
(R2-R3)/(R2+R3)	-2.8878	-4.1577	-4.1528
				TTL/F	4.1279	3.8379	3.8538

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

Claims

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

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

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

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

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

the fourth lens has 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 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, wherein the second lens and the third lens are cemented to each other to form a first cemented lens.

3. An optical lens according to claim 1, wherein the fourth lens, the fifth lens and the sixth lens are cemented to form a second cemented lens.

4. An optical lens according to claim 1, characterized in that at least one of the first lens and the sixth lens is an aspherical mirror.

5. An optical lens according to any one of claims 1 to 4, wherein an overall optical length TTL of the optical lens and a total group focal length value F of the optical lens satisfy: TTL/F is less than or equal to 5.

6. An optical lens according to any of claims 1-4, characterized in that between an optical back focus BFL of the optical lens and a lens group length TL of the optical lens satisfies: BFL/TL is more than or equal to 0.25.

7. An optical lens according to any one of claims 1 to 4, characterized in that an air interval d5 between the third lens and the fourth lens and an optical total length TTL of the optical lens satisfy: d5/TTL is more than or equal to 0.008.

8. An optical lens according to any one of claims 1 to 4, wherein the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens satisfy: D/H/FOV is less than or equal to 0.025.

9. An optical lens according to any one of claims 1 to 4, characterized in that a focal length value F3 of the third lens and a focal length value F2 of the second lens satisfy: the ratio of F3 to F2 is less than or equal to 1.5.

10. An optical lens according to any one of claims 1 to 4, characterized in that a combined focal length value F23 of the second lens and the third lens and a full set of focal length values F of the optical lens satisfy: F23/F is more than or equal to 1.5 and less than or equal to 4.

11. An optical lens barrel according to any one of claims 1 to 4, wherein the central radius of curvature R2 of the image side surface of the first lens and the central radius of curvature R3 of the object side surface of the second lens satisfy: the ratio of (R2-R3)/(R2+ R3) is less than or equal to-6 and less than or equal to-0.8.

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

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

the first lens, the second lens and the fifth lens each have a negative optical power;

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

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

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

the optical back focus BFL of the optical lens and the lens group length TL of the optical lens meet the following conditions: BFL/TL is more than or equal to 0.25.