CN109557644B

CN109557644B - Optical lens and imaging apparatus

Info

Publication number: CN109557644B
Application number: CN201910068112.3A
Authority: CN
Inventors: 周宝; 马奥林; 王东方
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2019-01-24
Filing date: 2019-01-24
Publication date: 2021-10-22
Anticipated expiration: 2039-01-24
Also published as: CN109557644A

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, a sixth lens, and a seventh 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, and the object side surface and the image side surface of the second lens are both concave surfaces; 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; 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; and the seventh lens has positive focal power, and the object side surface of the seventh lens is a convex surface and the image side surface of the seventh lens is a concave surface. The optical lens can realize at least one of the advantages of high resolution, large aperture, miniaturization, small front-end aperture, long back focus, low cost and the like.

Description

Optical lens and imaging apparatus

Technical Field

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

Background

Automatic driving is one of key technologies for realizing intelligent transportation, and is also an inevitable trend for the development of the future transportation field.

Optical lenses are currently one of the important components of automotive vision sensors, and their performance directly affects safety during automatic driving. First, the optical lens used in automatic driving requires high pixel requirements, and in order to improve the resolution, a larger number of lens structures are generally used, which seriously affects the miniaturization of the lens. Meanwhile, such optical lenses require a larger aperture to realize clear identification in a low-light environment and adapt to different driving environments.

Therefore, there is a need in the market for an optical lens that has high resolution, small size, low cost, and the like, and can be used in low light environments to meet the requirements of, for example, automotive applications.

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, a sixth lens, and a seventh lens. The first lens can have negative focal power, and 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 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; the sixth lens element can have a positive focal power, and both the object-side surface and the image-side surface of the sixth lens element are convex; and the seventh lens element can have a positive power, and has a convex object-side surface and a concave image-side surface.

The second lens and the third lens can be mutually glued to form a first cemented lens.

Wherein the fourth lens, the fifth lens and the sixth lens can be cemented to form a second cemented lens.

The first lens, the sixth lens and the seventh lens can be aspheric lenses, and at least one of the object side surface and the image side surface of each of the first lens, the sixth lens and the seventh lens can be aspheric.

The third lens can be a glass aspheric lens, and at least one of the object-side surface and the image-side surface of the third lens can be aspheric.

Wherein, the total optical length TTL of the optical lens and the whole group of focal length values F of the optical lens can satisfy the following conditions: TTL/F is less than or equal to 5.

Wherein, the maximum field angle FOV of the optical lens, the maximum light-passing 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 can satisfy: D/H/FOV is less than or equal to 0.025.

Wherein, can satisfy between focus BFL behind optical lens's optics and optical lens's the battery of lens length TL: BFL/TL is more than or equal to 0.25.

Wherein, the focal length value F2 of the second lens and the focal length value F3 of the third lens can satisfy the following conditions: the absolute value of F2/F3 is more than or equal to 0.5 and less than or equal to 1.5.

Wherein, this optical lens can satisfy the conditional expression: 0.2 ≦ (SAG12/d12)/(SAG11/d11) ≦ 1.0, wherein d11 is a half aperture of the maximum clear aperture of the object-side surface of the seventh lens corresponding to the maximum angle of view of the optical lens, SAG11 is a rise SG value of the object-side surface of the seventh lens corresponding to the maximum angle of view of the optical lens, d12 is a half aperture of the maximum clear aperture of the image-side surface of the seventh lens corresponding to the maximum angle of view of the optical lens, and SAG12 is a rise SG value of the image-side surface of the seventh lens corresponding to the maximum angle of view of the optical lens.

Wherein, the air interval T5 between the first cemented lens and the second cemented lens and the total optical length TTL of the optical lens can satisfy: T5/TTL is less than or equal to 0.02.

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, a sixth lens, and a seventh lens. The first lens, the second lens and the fifth lens can all have negative focal power; the third lens, the fourth lens, the sixth lens and the seventh 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 total optical length TTL of the optical lens and the whole group of focal length values F of the optical lens can meet the following requirements: TTL/F is less than or equal to 5.

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

The object side surface and the image side surface of the second lens can be both concave surfaces.

The object-side surface and the image-side surface of the third lens can both be convex surfaces.

The object-side surface and the image-side surface of the fourth lens element can both be convex surfaces.

The object side surface and the image side surface of the fifth lens can be both concave surfaces.

The object-side surface and the image-side surface of the sixth lens element can both be convex.

The object-side surface of the seventh lens element can be convex, and the image-side surface of the seventh lens element can be concave.

Still another aspect of the present application provides an imaging apparatus that may include the optical lens according to the above-described embodiment and an imaging element for converting an optical image formed by the optical lens into an electrical signal.

The optical lens adopts seven lenses, the focal power of each lens is reasonably distributed and the cemented lens is formed by optimally setting the shape of the lenses, so that at least one of the beneficial effects of high resolution, large aperture, miniaturization, small front end aperture, long back focus, low cost 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;

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

fig. 4 schematically shows the half caliber d/d 'of the maximum clear caliber of the object/image side of the lens and the corresponding rise Sg value SAG/SAG'.

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, seven lenses having optical power, i.e., a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The seven lenses are arranged in order from the 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 in a meniscus shape with the convex surface facing the object side, so that light rays with a large view field can be collected as far as possible, the light rays enter the rear optical system, the light flux is increased, and the whole large view field range can be realized. In practical application, considering the outdoor installation and use environment of the vehicle-mounted application-like lens, the lens can be in severe weather such as rain, snow and the like, and the first lens is arranged in the meniscus shape with the convex surface facing the object side, so that water drops and the like can slide off favorably, and the influence on the imaging quality of the lens is reduced.

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 fourth lens is set to have positive focal power, and a fourth lens with positive focal power is used after the set aperture stop, so that the aberration generated by the front lens group can be further corrected, and meanwhile, the light beams are converged again, so that the aperture of the lens can be enlarged, the total length of the lens can be shortened, and the optical system is more compact.

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.

The seventh lens element can have a positive power, and can have a convex object-side surface and a concave image-side surface. The seventh lens can smoothly transit the light passing through the front optical system to the imaging surface, thereby reducing the overall length of the system.

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, the effective beam-collecting of the light rays entering the optical system can be facilitated, 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 optical lens according to the present application may further include a filter disposed between the seventh 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 a double cemented lens, and is composed of a negative lens (i.e., the second lens) and a positive lens (i.e., the third lens), wherein the positive lens has a higher refractive index, the negative lens has a lower refractive index (compared with the positive lens), and the matching of the high and low refractive indexes can be beneficial to the rapid transition of the front light, and the aperture of the diaphragm is increased to meet the requirement of night vision. The adoption of the cemented lens can effectively reduce the chromatic aberration of the system, and the whole structure of the optical system is compact, thereby meeting the miniaturization requirement. Meanwhile, the tolerance sensitivity problems of inclination/core deviation and the like of the lens unit caused in the assembling process can be reduced.

In an exemplary embodiment, the fourth lens, the fifth lens, and the sixth lens may be combined into a second cemented lens by cementing an image-side surface of the fourth lens with an object-side surface of the fifth lens, and cementing an image-side surface of the fifth lens with an object-side surface of the sixth lens. The second cemented lens is a tri-cemented lens, and the use of the tri-cemented lens can have at least one of the following beneficial effects: the air intervals among the three lenses are reduced, and the total length of the whole optical system is reduced; the assembly parts among the three lenses are reduced, the working procedures are reduced, the assembly is convenient, and the cost is reduced; the tolerance sensitivity problems of inclination/core deviation and the like generated in the assembling process of the lens unit are reduced; fourthly, the light quantity loss caused by reflection among the lenses is reduced, and the relative illumination of the system is improved; the field curvature can be further reduced, and the off-axis point aberration of the system can be corrected.

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 to improve the resolution, and enables the optical system to be compact as a whole to meet 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 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 ensure the small caliber at the front end.

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 0.3. By satisfying the condition that BFL/TL is more than or equal to 0.25, the characteristic of the back focal length can be realized, which is beneficial to the assembly of the optical lens.

In an exemplary embodiment, a focal length value F2 of the second lens and a focal length value F3 of the third lens may satisfy: the absolute value of F2/F3 is more than or equal to 0.5 and less than or equal to 1.5, and more preferably, the absolute value of F2/F3 is more than or equal to 0.8 and less than or equal to 1.2. Through making the focus numerical value of two adjacent lenses close, can help the mild excessive of light, be favorable to promoting like matter.

In an exemplary embodiment, the half aperture d11 of the maximum clear aperture of the seventh lens object-side surface corresponding to the maximum field angle of the optical lens and the corresponding rise SG value SAG11, and the half aperture d12 of the maximum clear aperture of the seventh lens image-side surface corresponding to the maximum field angle of the optical lens and the corresponding rise SG value SAG12 may satisfy: 0.2. ltoreq. SAG12/d12)/(SAG11/d 11. ltoreq.1.0, and desirably, 0.4. ltoreq. SAG12/d12)/(SAG11/d 11. ltoreq.0.8. The shapes of the two surfaces of the seventh lens are close through arrangement, so that the peripheral light can be smoothly transited, and the sensitivity of the lens can be reduced.

In an exemplary embodiment, an air interval T5 between the first and second cemented lenses and an optical total length TTL of the optical lens may satisfy: T5/TTL is less than or equal to 0.02, and more preferably, T5/TTL is less than or equal to 0.015. The central distance between two groups of adjacent cemented lenses is small, so that light rays near the gentle transition diaphragm can be favorably realized, and the image quality can be favorably improved.

In an exemplary embodiment, the first lens, the sixth lens and the seventh lens of the optical lens according to the present application may each employ an aspherical mirror, and in particular, at least one of their respective object-side and image-side surfaces may be aspherical. In addition, the third lens element may also be an aspherical lens element, and in particular, at least one of the object-side surface and the image-side surface thereof may be aspherical. 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 adopt an aspherical lens to further improve the resolution quality. The seventh lens adopts an aspheric lens, so that various aberrations of the optical system can be fully corrected, and the resolution of the optical system can be improved on the premise of compact structure. 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 the aspheric lenses, for example, when the resolution quality of the optical lens is focused, the aspheric lenses may be used for the first lens to the seventh lens.

In an exemplary embodiment, the third lens may be a glass lens. Generally, the thermal expansion coefficient of a lens made of plastic is large, and when the ambient temperature change of the lens is large, the lens made of plastic causes the optical back focus change of the lens to be large. The glass lens can reduce the influence of temperature on the optical back focus of the lens, but has higher cost. The application of the glass lens can improve the temperature stability of the optical lens, and is particularly suitable for the application of a front-view lens. Ideally, the third lens may be a glass aspheric lens to further improve the resolution. It should be understood that, in order to improve the stability of the lens, the optical lens according to the present application may increase the number of glass lenses, for example, when focusing on the stability of the optical lens, the glass lenses may be used for the first lens to the seventh lens.

According to the optical lens of the above embodiment of the application, the shape of the lens is optimally set, the focal power is reasonably distributed, the lens material is reasonably selected, high resolution can be realized by using 7 pieces of framework, and the requirements of small size, low sensitivity and high production yield of the lens on low cost can be considered. The main light angle line angle CRA of the optical lens is small, stray light generated when the rear end of light rays is emitted to a lens barrel is avoided, the optical lens can be well matched with a vehicle-mounted chip, and color cast and dark angle phenomena cannot be generated. The optical lens has a large aperture, is good in imaging effect, can achieve high-definition level of image quality, and can ensure the definition of images even at night or in a weak light environment. Therefore, the optical lens according to the above-described embodiment of the present application can better meet the requirements of, for example, an in-vehicle application.

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 seventh lens image side surface 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 seventh lens of the last lens.

However, it will be appreciated by those skilled in the art that the number of lenses constituting the lens barrel may be varied to achieve the various results and advantages described in the present specification without departing from the claimed subject matter. For example, although seven lenses are exemplified in the embodiment, the optical lens is not limited to include seven lenses. The optical lens may also include other numbers of lenses, if desired.

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

Example 1

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

As shown in fig. 1, the optical lens 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, a sixth lens L6, and a seventh lens L7.

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 both the object-side surface S4 and the image-side surface S5 being convex. 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 seventh lens L7 is a meniscus lens with positive power, with the object side S11 being convex and the image side S12 being concave.

The first lens L1, the third lens L3, the sixth lens L6 and the seventh lens L7 are aspheric lenses, wherein object-side surfaces and image-side surfaces (S1-S2, S11-S12) of the first lens L1 and the seventh lens L7 are aspheric surfaces, and image-side surfaces (S5 and S10) of the third lens L3 and the sixth lens L6 are aspheric surfaces.

Optionally, the optical lens may further include a filter L8 and/or a protective lens L8' having an object side S13 and an image side S14. Filter L8 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 the radius of curvature R and the thickness T (it is understood that T is₁Is the center thickness, T, of the first lens L1₂An air space between the first lens L1 and the second lens L2, and so on), a refractive index Nd, and an abbe number Vd, wherein the radius of curvature R and the thickness T are both in millimeters (mm).

TABLE 1

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	6.3192	0.9928	1.59	61.25
2	3.6856	6.0160
					3	-5.9539	2.6484	1.52	64.21
4	6.7721	2.9673	1.74	49.34
					5	-9.4301	0.1819
STO	All-round	0.1901
					7	10.3480	3.9244	1.69	54.86
8	-12.6076	0.7043	1.85	23.79
					9	12.5780	1.8021	1.59	61.25
10	75.3456	1.0637
					11	10.6292	1.9957	1.59	68.53
12	44.0476	1.0006
					13	All-round	1.0500	1.52	64.21
14	All-round	5.2823
					IMA	All-round

The present embodiment adopts seven 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 has the advantages of high resolution, large aperture, miniaturization, small front end aperture, long back focus, low cost 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 up

The inverse of the radius of curvature R in table 1); 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 of the aspherical lens surfaces S1 to S2, S5, S10, S11 to S12 that can be used in example 1.

TABLE 2

Flour mark

K

A

B

C

D

E

1

-0.2295

-2.9676E-03

8.2263E-05

-1.8385E-06

2.3957E-08

-1.8821E-10

2

-2.3436

4.6394E-04

-8.6542E-06

1.3279E-06

-6.3641E-09

-8.8033E-10

5

-1.7438

1.8359E-04

2.6530E-06

-7.7406E-08

1.1640E-08

-3.0345E-01

10

-102.0968

-3.3515E-03

1.9203E-04

-5.1850E-06

1.3642E-07

-1.4706E-09

11

-3.1395

-3.1246E-03

6.8070E-05

9.7630E-06

-4.5331E-07

7.1341E-09

12

99.2346

-4.5219E-04

-4.6080E-05

1.1035E-05

-4.9353E-07

1.0370E-08

Table 3 below gives the total optical length TTL of the optical lens of example 1 (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 entire group focal length value F of the optical lens, the optical back focus BFL of the optical lens (i.e., the on-axis distance from the center of the image-side surface S12 of the last lens L7 to the imaging surface IMA), the lens group length TL 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 center of the image-side surface S12 of the last lens L7), the focal length values F2 and 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 field angle of the optical lens, the high image H corresponding to the maximum field angle of the optical lens, the maximum field angle of the FOV corresponding to the maximum clear aperture D of the seventh lens SGs 11 corresponding to the maximum field angle of the optical lens SAG and the maximum aperture D of the half aperture SG 29 of the optical lens SGs 11 6 corresponding to the maximum field angle of the seventh lens L11 6 corresponding to the maximum field angle of the optical lens SAG 26 (see fig. 4), a half aperture d12 of the maximum clear aperture of the image-side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and its corresponding rise SG value SAG12 (see fig. 4), and an air space T5 between two adjacent cemented lenses (i.e., the first cemented lens and the second cemented lens).

TABLE 3

TTL(mm)	29.8195	FOV(°)	77.0000
				F(mm)	7.1882	SAG11(mm)	0.5300
BFL(mm)	7.3329	SAG12(mm)	0.3400
				TL(mm)	22.4866	d11(mm)	4.2200
F2(mm)	-5.7027	d12(mm)	4.0100
				F3(mm)	5.7255	T5(mm)	0.3720
D(mm)	12.3423
				H(mm)	9.6640

In the present embodiment, TTL/F is 4.1484 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; the distance between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens is 0.3261; 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 a D/H/FOV of 0.0166; a focal length value F2 of the second lens L2 and a focal length value F3 of the third lens L3 satisfy | F2/F3| ═ 0.9960; a half aperture d11 of the maximum clear aperture of the object side surface S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG11 corresponding thereto satisfy (SAG12/d12)/(SAG11/d11) 0.6751 between a half aperture d12 of the maximum clear aperture of the image side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG12 corresponding thereto; and an air interval T5 between two adjacent groups of cemented lenses (i.e., the first cemented lens and the second cemented lens) and an overall optical length TTL of the optical lens satisfy T5/TTL of 0.0125.

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, a sixth lens L6, and a seventh lens L7.

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 high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S1-S2, S5, S10, S11-S12 in example 2. Table 6 below gives the total optical length TTL of the optical lens, the entire group focal length value F of the optical lens, the optical back focus BFL of the optical lens, the lens group length TL of the optical lens, the focal length values F2 and 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 field angle of the optical lens, the image height H corresponding to the maximum field angle of the optical lens, the maximum field angle FOV of the optical lens, the half aperture D11 of the maximum clear aperture of the object-side surface S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and the corresponding vector height SG 11, the half aperture D12 of the maximum clear aperture of the image-side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and the corresponding height SG 12, and the air space T5 between two groups of adjacent lenses.

TABLE 4

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	6.2429	0.9979	1.59	61.12
2	3.6801	5.7783
					3	-5.8879	2.8011	1.52	64.05
4	6.8018	3.0016	1.74	49.34
					5	-9.5437	0.1444
STO	All-round	0.1585
					7	10.3045	3.9729	1.69	54.86
8	-12.5191	0.6008	1.85	23.79
					9	12.7818	2.0384	1.59	61.12
10	90.5636	1.0626
					11	10.6127	2.1041	1.59	68.53
12	43.4421	1.0002
					13	All-round	1.0500	1.52	64.21
14	All-round	5.1483
					IMA	All-round

TABLE 5

Flour mark

K

A

B

C

D

E

1

-0.2299

-3.0886E-03

8.2252E-05

-1.8386E-06

2.3945E-08

-1.8886E-10

2

-2.3413

4.4620E-04

-8.5643E-06

1.3292E-06

-6.3785E-09

-8.8183E-10

5

-1.7438

1.8359E-04

2.6530E-06

-7.7406E-08

1.1640E-08

-3.0345E-01

10

-102.0968

-3.3515E-03

1.9203E-04

-5.1850E-06

1.3642E-07

-1.4706E-09

11

-3.1395

-3.1246E-03

6.8070E-05

9.7630E-06

-4.5331E-07

7.1341E-09

12

99.2345

-4.5219E-04

-4.6080E-05

1.1035E-05

-4.9353E-07

1.0370E-08

TABLE 6

TTL(mm)	29.8600	FOV(°)	79.5000
				F(mm)	7.1600	SAG11(mm)	0.6100
BFL(mm)	7.2000	SAG12(mm)	0.3600
				TL(mm)	22.6600	d11(mm)	4.2900
F2(mm)	-5.6600	d12(mm)	4.0300
				F3(mm)	5.7700	T5(mm)	0.3029
D(mm)	12.1000
				H(mm)	9.6600

In the present embodiment, TTL/F is 4.1704 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; the distance between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens is 0.3177; 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 a D/H/FOV of 0.0158; a focal length value F2 of the second lens L2 and a focal length value F3 of the third lens L3 satisfy | F2/F3| ═ 0.9809; a half aperture d11 of the maximum clear aperture of the object side surface S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG11 corresponding thereto satisfy (SAG12/d12)/(SAG11/d11) 0.6282 between a half aperture d12 of the maximum clear aperture of the image side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG12 corresponding thereto; and an air interval T5 between two adjacent groups of cemented lenses (i.e., the first cemented lens and the second cemented lens) and an optical total length TTL of the optical lens satisfy T5/TTL of 0.0101.

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, a sixth lens L6, and a seventh lens L7.

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 high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S1-S2, S5, S10, S11-S12 in example 3. Table 9 below gives the total optical length TTL of the optical lens, the entire group focal length value F of the optical lens, the optical back focus BFL of the optical lens, the lens group length TL of the optical lens, the focal length values F2 and 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 field angle of the optical lens, the image height H corresponding to the maximum field angle of the optical lens, the maximum field angle FOV of the optical lens, the half aperture d11 of the maximum clear aperture of the object-side surface S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and the corresponding rise SG value SAG11, the half aperture d12 of the maximum clear aperture of the image-side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and the corresponding rise SG value SAG12, and the air gap T5 between two adjacent cemented lenses.

TABLE 7

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	6.2206	0.9896	1.59	61.12
2	3.6780	5.7272
					3	-5.8525	2.8289	1.52	64.05
4	6.7987	3.0075	1.74	49.34
					5	-9.5539	0.1600
STO	All-round	0.1962
					7	10.3263	3.9876	1.69	54.86
8	-12.3804	0.5996	1.85	23.79
					9	12.9474	2.0636	1.59	61.12
10	99.1495	1.0603
					11	10.6210	2.1356	1.59	61.12
12	43.3211	1.0008
					13	All-round	1.0500	1.52	64.21
14	All-round	5.2980
					IMA	All-round

TABLE 8

Flour mark

K

A

B

C

D

E

1

-0.2303

-3.0187E-03

8.2269E-05

-1.8381E-06

2.3935E-08

-1.9034E-10

2

-2.3404

4.5297E-04

-8.5288E-06

1.3240E-06

-6.8469E-09

-9.0600E-10

5

-1.7432

1.8053E-04

2.6619E-06

-7.6286E-08

-1.1716E-08

-3.0108E-01

10

-101.0658

-3.2111E-03

1.9187E-04

-5.1969E-06

1.3609E-07

-1.4908E-09

11

-3.1433

-3.1448E-03

6.8121E-05

9.7591E-06

-4.5421E-07

7.1101E-09

12

98.3540

-4.5329E-04

-4.6001E-05

1.1040E-05

-4.9348E-07

1.0357E-08

TABLE 9

TTL(mm)	30.1000	FOV(°)	78.0000
				F(mm)	7.1800	SAG11(mm)	0.6100
BFL(mm)	7.3500	SAG12(mm)	0.3800
				TL(mm)	22.7500	d11(mm)	4.3100
F2(mm)	-5.6400	d12(mm)	4.0700
				F3(mm)	5.7700	T5(mm)	0.3562
D(mm)	12.2000
				H(mm)	9.6600

In the present embodiment, TTL/F is 4.1922 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; the distance between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens is 0.3231; 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 a D/H/FOV of 0.0162; a focal length value F2 of the second lens L2 and a focal length value F3 of the third lens L3 satisfy | F2/F3| ═ 0.9775; a half aperture d11 of the maximum clear aperture of the object side surface S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG11 corresponding thereto satisfy (SAG12/d12)/(SAG11/d11) 0.6597 between a half aperture d12 of the maximum clear aperture of the image side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG12 corresponding thereto; and the air space T5 between two adjacent groups of cemented lenses (i.e., the first cemented lens and the second cemented lens) and the total optical length TTL of the optical lens satisfy T5/TTL of 0.0118.

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

Watch 10

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 in which the number of lenses having optical power is seven, which are: the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element are sequentially arranged 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, 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;

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; and

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

wherein, the total optical length TTL of the optical lens and the whole group of focal length values F of the optical lens satisfy: TTL/F is less than or equal to 5; and

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

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 barrel according to claim 1, wherein the first lens element, the sixth lens element and the seventh lens element are each an aspherical lens element, and at least one of an object-side surface and an image-side surface of each of the first lens element, the sixth lens element and the seventh lens element is aspherical.

4. An optical lens according to claim 1, characterized in that the third lens is a glass aspherical lens and at least one of the object-side and image-side surfaces of the third lens is aspherical.

5. 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(/ °).

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 a focal length value F2 of the second lens and a focal length value F3 of the third lens satisfy: the absolute value of F2/F3 is more than or equal to 0.5 and less than or equal to 1.5.

8. An optical lens according to any one of claims 1 to 4, characterized in that the conditional expression is satisfied:

0.2≤(SAG12/d12)/(SAG11/d11)≤1.0，

wherein d11 is a half aperture of the maximum clear aperture of the object-side surface of the seventh lens element corresponding to the maximum field angle of the optical lens,

SAG11 is a rise SG value of an object side surface of the seventh lens corresponding to a maximum field angle of the optical lens,

d12 is a half aperture of the maximum clear aperture of the image-side surface of the seventh lens element corresponding to the maximum angle of view of the optical lens, an

SAG12 is a rise SG value of an image side surface of the seventh lens corresponding to the maximum field angle of the optical lens.

9. An optical lens according to claim 2, wherein an air interval T5 between the first cemented lens and the second cemented lens and an optical total length TTL of the optical lens satisfy: T5/TTL is less than or equal to 0.02.

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