CN109683291B

CN109683291B - Optical lens and imaging apparatus

Info

Publication number: CN109683291B
Application number: CN201910125818.9A
Authority: CN
Inventors: 周召涛; 王东方
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2019-02-20
Filing date: 2019-02-20
Publication date: 2021-05-07
Anticipated expiration: 2039-02-20
Also published as: CN109683291A

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 and a fifth 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 positive focal power, and both the object side surface and the image side surface of the second lens are convex surfaces; the third lens can have negative focal power, and the image side surface of the third lens is a concave surface; 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; and the fifth lens element can have a negative power, and the object-side surface of the fifth lens element is convex and the image-side surface of the fifth lens element is concave. The optical lens can realize at least one of the advantages of good imaging quality, long-focus telephoto, large field angle, large clear aperture, miniaturization 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 five lenses.

Background

With the development of science and technology and the improvement of application requirements, the optical lens is applied in more and more fields, and the requirement on the resolution of the optical lens is also improved. In addition, for safety reasons, optical lenses for vehicle applications are more demanding on many optical parameters.

The conventional way to improve the lens resolution is to increase the number of lenses, but this increases the lens size and manufacturing cost. Especially for the limited installation space of the vehicle-mounted lens module, it is very disadvantageous to achieve miniaturization and improve the system integration. In addition, in some specific application environments (e.g., active safety driving), the optical lens of the vehicle-mounted application class needs to be capable of detecting objects at a far-distance direction, which requires the lens to have a longer focal length, but also causes the lens to have a limited and smaller field angle. The traditional method is to simultaneously cooperate with a wide-angle lens with a large field angle range to enlarge the integral observation field of view and complete picture splicing by combining software; but this increases system cost and is detrimental to system integration.

Therefore, there is a need for an optical lens with a long-range view, a wide-range view, a small size and a low cost to meet the requirements of modern car driving 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 and a fifth 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 positive focal power, and both the object side surface and the image side surface of the second lens are convex surfaces; the third lens can have negative focal power, and the image side surface of the third lens is a concave surface; 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; and the fifth lens element can have a negative power, and the object-side surface of the fifth lens element is convex and the image-side surface of the fifth lens element is concave.

The object side surface of the third lens can be a convex surface. Alternatively or additionally, the object side surface of the third lens may be planar. Alternatively or additionally, the object side surface of the third lens may be concave.

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

The first lens, the third lens, the fourth lens and the fifth lens can be aspheric lenses.

Wherein, the curvature radius R1 of the object side surface of the first lens, the curvature radius R2 of the image side surface of the first lens and the center thickness d1 of the first lens can satisfy: R1/(R2+ d1) is more than or equal to 0.5 and less than or equal to 1.5.

The focal length value F2 of the second lens and the focal length value F of the whole group of the optical lens can satisfy: F2/F is more than or equal to 0.5 and less than or equal to 1.8.

The refractive index Nd2 of the lens of the second lens can meet Nd2 ≥ 1.6.

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 4.5.

The total optical length TTL of the optical lens, the maximum half field angle FOV of the optical lens, and the image height ImgH corresponding to the maximum half field angle of the optical lens may satisfy: TTL/ImgH/FOV is less than or equal to 0.25.

The whole group of focal length values F of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens can satisfy the following conditions: F/ImgH is more than or equal to 1.2.

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 and a fifth lens. The first lens, the third lens and the fifth lens can all have negative focal power; the second lens and the fourth lens may each have a positive optical power; the third lens and the fourth lens can be mutually glued to form a 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 4.5.

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 convex surfaces.

The object-side surface of the third lens element can be convex, and the image-side surface of the third lens element can be concave. Alternatively or additionally, the object side surface of the third lens may be planar and the image side surface may be concave. Alternatively or additionally, the object side surface and the image side surface of the third lens may both be concave.

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

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

The refractive index Nd2 of the lens of the second lens can meet Nd2 ≥ 1.6.

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 five lenses, for example, the shapes of the lenses are optimally set, the focal power of each lens is reasonably distributed, the cemented lens is formed, and the like, so that at least one of the beneficial effects of good imaging quality, long-focus telephoto, large field angle, large clear aperture, miniaturization 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, five lenses having optical power, i.e., a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The five 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, and the aspheric surface type is selected, so that the incident angle of incident light on the attack surface can be reduced, more light can be collected to enter the optical system, the luminous flux is increased, and higher imaging quality is realized. In addition, in practical application, considering the outdoor installation and use environment of the vehicle-mounted application-type lens, the lens can be in severe weather such as rain and snow, and the first lens is arranged in a 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 can be reduced.

The second lens can have positive optical power, and both the object side surface and the image side surface of the second lens can be convex. The second lens is a convergent lens, and can compress the angle of incident light rays to enable the incident light rays to smoothly enter the rear diaphragm, so that the aperture of the lens is favorably reduced, the aperture of the diaphragm is increased, the light flux of a system is increased, and higher picture brightness is realized. Meanwhile, the second lens can be made of a material with a high refractive index and a low Abbe number so as to compensate the on-axis aberration of the system and improve the imaging quality.

The third lens element can have a negative power, and can optionally have a convex, planar, or concave object-side surface and a concave image-side surface.

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 power, and can have a convex object-side surface and a concave image-side surface. The meniscus shape with the convex surface of the fifth lens facing the object side may be advantageous to balance curvature of field and astigmatism of the system.

In an exemplary embodiment, a stop for limiting the light beam may be disposed between, for example, the second lens and the third lens to further improve the imaging quality of the lens. When the diaphragm is arranged between the second lens and the third lens, the front end aperture of the system can be favorably reduced, and the total length of the system is shortened. Ideally, when the stop is disposed between the second lens element and the third lens element, 0.3 ≦ SL/TTL ≦ 0.7 (where SL is the on-axis distance from the stop STO to the image plane IMA, and TTL is the total optical length of the optical lens) may be satisfied. 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.

Optionally, in an exemplary embodiment, the optical lens according to the present application may further include a filter disposed between the fifth lens and the imaging surface to filter light rays having different wavelengths, as needed; 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 third lens and the fourth lens may be combined into a cemented lens by cementing the image-side surface of the third lens with the object-side surface of the fourth lens. This cemented lens is two cemented lens, comprises a piece of negative lens (i.e. third lens) and a piece of positive lens (i.e. fourth lens), and wherein, negative lens arrange in the front, and positive lens arrange the back, can diverge the back with the place ahead light and converge again gently transition to the back again, more is favorable to reducing the total length of system. The double-cemented lens can perform self-achromatization, can compensate the residual chromatic aberration of the system and correct the axial point monochromatic aberration, and is beneficial to reducing the assembly tolerance sensitivity and improving the production yield. The cemented lens shares the whole chromatic aberration correction of the system, can effectively correct aberration so as to improve the resolution, and enables the optical system to be compact as a whole and meets the miniaturization requirement.

In an exemplary embodiment, the radius of curvature R1 of the object-side surface of the first lens, the radius of curvature R2 of the image-side surface of the first lens, and the center thickness d1 of the first lens may satisfy: R1/(R2+ d1) is 0.5. ltoreq.1.5, and more preferably 0.8. ltoreq.R 1/(R2+ d1) is 1.2. Through the specific lens shape setting of first lens, can reduce the optical path difference of peripheral light and central light, collect the light of bigger angle and get into rear optical system, and reduce the camera lens front end bore, reduce the volume, realize miniaturization and reduce cost when being favorable to promoting the resolution.

In an exemplary embodiment, a focal length value F2 of the second lens and a focal length value F of the entire group of the optical lens may satisfy: F2/F is 0.5. ltoreq. F2/F is 1.8, and more preferably, F2/F is 0.8. ltoreq. F2/F. ltoreq.1.5. The light trend between the first lens and the third lens is controlled by satisfying the conditional expression that F2/F is more than or equal to 0.5 and less than or equal to 1.8, so that the aperture of the rear end of the lens can be reduced, and the aberration caused by large-angle light entering through the first lens is reduced.

In an exemplary embodiment, the refractive index Nd2 of the lens of the second lens can satisfy Nd2 ≧ 1.6, and more desirably, can further satisfy Nd2 ≧ 1.65. The second lens is made of a high-refractive-index material, so that the caliber of the lens can be reduced, the imaging quality can be improved, the tolerance sensitivity of a system can be reduced, the production yield can be improved, and the production cost can be reduced.

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 4.5, and more ideally, TTL/F is less than or equal to 4. The condition TTL/F is less than or equal to 4.5, and the miniaturization characteristic of the system can be ensured.

In an exemplary embodiment, the total optical length TTL of the optical lens, the maximum half field angle FOV of the optical lens, and the image height ImgH corresponding to the maximum half field angle of the optical lens may satisfy: TTL/ImgH/FOV is less than or equal to 0.25, and more ideally, TTL/ImgH/FOV is less than or equal to 0.2. The TTL/ImgH/FOV satisfies the conditional expression of being less than or equal to 0.25, and a larger field angle and a smaller lens volume can be realized under a certain imaging height.

In an exemplary embodiment, the relationship between the entire set of focal length values F of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens may satisfy: F/ImgH is not less than 1.2, and more preferably, F/ImgH is not less than 1.4. The optical lens meets the condition that the F/ImgH is more than or equal to 1.2, has long focal length, can be beneficial to clear imaging of a long-distance object, and realizes long-focus telephoto.

In an exemplary embodiment, the first lens, the third lens, the fourth lens and the fifth lens of the optical lens according to the present application may each 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 fifth lens adopts an aspheric lens to correct high-order aberration of a large-angle field of view, and imaging quality is improved. It is understood that the optical lens according to the present application may increase the number of aspherical lenses in order to improve the imaging quality. For example, in the case where the emphasis is on the resolution quality, the first to fifth lenses may each employ an aspherical mirror.

In an exemplary embodiment, an optical lens according to the present application may employ a plastic lens or 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.

According to the optical lens of the above embodiment of the present application, the lens shape is optimally set, the focal power is reasonably distributed, and the lens material is reasonably selected, so that the lens design with high resolution capability is realized on the premise of only using 5 lenses. The optical lens realizes long focal length, so that the lens has long-focus telephoto capability. The optical lens realizes a large field angle, does not need an additional lens to expand the whole observation field, and reduces the cost of the driving assistance system. The optical lens realizes large light-passing aperture, increases the brightness of an imaging picture, can better image even in a dark environment, and improves the active safety. The optical lens realizes the miniaturization of the lens and is convenient to install and integrate in a limited space. 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.

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 five lenses are exemplified in the embodiment, the optical lens is not limited to include five lenses. The optical lens may also include other numbers of lenses, if desired.

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

Example 1

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

As shown in fig. 1, the optical lens includes, in order from an object side to an image side along an optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5.

The first lens L1 is a meniscus lens with negative power, with the object side S1 being convex and the image side S2 being concave.

The second lens L2 is a biconvex lens with positive optical power, and has both the object-side surface S3 and the image-side surface S4 being convex.

The third lens L3 is a biconcave lens with negative optical power, and both the object-side surface S6 and the image-side surface S7 are concave. 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. Wherein, the third lens L3 and the fourth lens L4 are cemented with each other to form a cemented lens.

The fifth lens L5 is a meniscus lens with negative power, with the object side S9 being convex and the image side S10 being concave.

The first lens L1, the third lens L3, the fourth lens L4, and the fifth lens L5 are aspheric lenses, and both object-side surfaces and image-side surfaces of the aspheric lenses are aspheric.

In the optical lens of the present embodiment, a stop STO may be provided between the second lens L2 and the third lens L3 to improve the imaging quality. The light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging surface S11.

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

The present embodiment adopts five 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 good imaging quality, telephoto, large field angle, large clear aperture, miniaturization 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 cone coefficients k and high-order term coefficients A, B, C, D and E of aspherical lens surfaces S1 to S2 and S6 to S10 that can be used in example 1.

TABLE 2

Flour mark

K

A

B

C

D

E

1

-6.1383

5.7349E-03

-7.8450E-04

3.4386E-05

-5.8909E-07

1.4540E-09

2

-0.8536

-4.7730E-03

-1.2992E-03

1.4347E-04

-3.8460E-06

8.8336E-10

6

89.0314

-3.6847E-03

3.2912E-04

-2.5443E-05

-7.8350E-08

1.3571E-07

7

-0.9752

-7.7121E-03

1.8154E-03

-9.2494E-05

-3.1215E-05

2.2199E-06

8

-2.3035

1.0281E-03

-3.7914E-04

-5.5528E-07

-1.2901E-06

3.5136E-07

9

-147.1879

4.7141E-03

-2.2743E-04

-2.9763E-05

5.2469E-06

-1.8705E-07

10

-17.2746

-3.1133E-03

5.1629E-04

-6.2178E-05

3.6246E-06

-3.9194E-08

Table 3 below gives a curvature radius R1 of the object-side surface S1 of the first lens L1, a curvature radius R2 of the image-side surface S2 of the first lens L1, a center thickness d1 of the first lens L1, a focal length value F2 of the second lens L2, a full-group focal length value F of the optical lens, a lens refractive index Nd2 of the second lens L2, an on-axis distance SL from the stop STO to the imaging surface IMA, an optical total length TTL 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 imaging surface IMA), an image height ImgH corresponding to a half-maximum field angle of the optical lens, and a half-maximum field angle FOV of the optical lens of embodiment 1.

TABLE 3

R1(mm)	4.2579	SL(mm)	11.4309
				R2(mm)	2.0003	TTL(mm)	21.0234
d1(mm)	2.6817	ImgH(mm)	3.5929
				F2(mm)	5.8204	FOV(°)	55.0000
F(mm)	6.2366
				Nd2	1.7447

In the present embodiment, the on-axis distance SL from the stop STO to the imaging plane IMA and the total optical length TTL of the optical lens satisfy SL/TTL of 0.5437; R1/(R2+ d1) ═ 0.9094 among the radius of curvature R1 of the object-side surface S1 of the first lens L1, the radius of curvature R2 of the image-side surface S2 of the first lens L1, and the center thickness d1 of the first lens L1; F2/F is 0.9333 between the focal length value F2 of the second lens L2 and the focal length value F of the entire group of the optical lens; the total optical length TTL of the optical lens and the whole group focal length value F of the optical lens meet the condition that TTL/F is 3.3710; the TTL/ImgH/FOV is 0.1064 between the total optical length TTL of the optical lens, the maximum half field angle FOV of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens; and F/ImgH is 1.7358 between the whole group focal length value F of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens.

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, and a fifth lens L5.

The third lens L3 is a plano-concave lens with negative power, and has a planar object-side surface S6 and a concave image-side surface S7. 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. Wherein, the third lens L3 and the fourth lens L4 are cemented with each other to form a cemented lens.

The first lens L1, the third lens L3, the fourth lens L4, and the fifth lens L5 are all aspheric lenses, wherein an image side surface S7 of the third lens L3 is aspheric, and an object side surface and an image side surface of each of the first lens L1, the fourth lens L4, and the fifth lens L5 are aspheric.

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). The following table 5 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 to S2 and S7 to S10 in example 2. Table 6 below gives the radius of curvature R1 of the object-side surface S1 of the first lens L1, the radius of curvature R2 of the image-side surface S2 of the first lens L1, the center thickness d1 of the first lens L1, the focal length value F2 of the second lens L2, the entire group focal length value F of the optical lens, the lens refractive index Nd2 of the second lens L2, the on-axis distance SL from the stop STO to the imaging surface IMA, the total optical length TTL of the optical lens, the image height ImgH corresponding to the maximum half field angle of the optical lens, and the maximum half field angle FOV of the optical lens of example 2.

TABLE 4

TABLE 5

Flour mark

K

A

B

C

D

E

1

-7.5984

5.4990E-03

-7.4970E-04

3.4136E-05

-6.7675E-07

4.2055E-09

2

-0.8288

-3.4279E-03

-1.0828E-03

1.2121E-04

-5.5263E-06

1.7386E-07

7

3.5362

9.0735E-04

2.2921E-03

-1.0098E-04

-2.6102E-05

1.4050E-06

8

-5.1890

1.0292E-03

-4.0582E-04

4.1165E-05

-5.7372E-06

5.3649E-07

9

-150.0169

4.0747E-03

-2.6428E-04

4.1561E-06

4.1864E-06

-2.3411E-07

10

-18.8967

-3.1450E-03

6.2406E-04

-4.4434E-05

5.6637E-07

2.4701E-07

TABLE 6

R1(mm)	4.4356	SL(mm)	10.5135
				R2(mm)	2.0927	TTL(mm)	20.6534
d1(mm)	2.4863	ImgH(mm)	3.5016
				F2(mm)	6.5296	FOV(°)	50.0000
F(mm)	6.0051
				Nd2	1.8669

In the present embodiment, the on-axis distance SL from the stop STO to the imaging plane IMA and the total optical length TTL of the optical lens satisfy SL/TTL of 0.5090; R1/(R2+ d1) ═ 0.9687 among the radius of curvature R1 of the object-side surface S1 of the first lens L1, the radius of curvature R2 of the image-side surface S2 of the first lens L1, and the center thickness d1 of the first lens L1; F2/F1.0873 is satisfied between the focal length value F2 of the second lens L2 and the focal length value F of the entire group of optical lenses; the total optical length TTL of the optical lens and the whole group focal length value F of the optical lens meet the condition that TTL/F is 3.4393; the TTL/ImgH/FOV is 0.1180 among the total optical length TTL of the optical lens, the maximum half-field angle FOV of the optical lens and the image height ImgH corresponding to the maximum half-field angle of the optical lens; and F/ImgH is 1.7150 between the whole group focal length value F of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens.

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, and a fifth lens L5.

The third lens L3 is a meniscus lens with negative power, with the object side S6 being convex and the image side S7 being concave. 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. Wherein, the third lens L3 and the fourth lens L4 are cemented with each other to form a cemented lens.

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). The following table 8 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 to S2 and S6 to S10 in example 3. Table 9 below gives the radius of curvature R1 of the object-side surface S1 of the first lens L1, the radius of curvature R2 of the image-side surface S2 of the first lens L1, the center thickness d1 of the first lens L1, the focal length value F2 of the second lens L2, the entire group focal length value F of the optical lens, the lens refractive index Nd2 of the second lens L2, the on-axis distance SL from the stop STO to the imaging surface IMA, the total optical length TTL of the optical lens, the image height ImgH corresponding to the maximum half field angle of the optical lens, and the maximum half field angle FOV of the optical lens of example 3.

TABLE 7

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	4.2032	2.7046	1.59	65.46
2	2.0080	4.2602
					3	13.5963	2.8942	1.74	35.25
4	-9.7394	0.3699
					STO	All-round	0.3475
6	29.0961	1.8635	1.73	25.70
					7	4.8118	3.5169	1.58	57.20
8	-3.9758	0.0997
					9	32.2553	2.5451	1.71	23.70
10	8.2244	3.3984
					IMA	All-round

TABLE 8

Flour mark

K

A

B

C

D

E

1

-7.9498

7.1177E-03

-8.7451E-04

3.6709E-05

-5.7861E-07

1.5208E-10

2

-0.8656

-4.5361E-03

-1.1682E-03

1.2629E-04

-3.8196E-06

-3.2531E-08

6

-152.0700

5.1489E-05

2.1828E-05

2.7079E-06

-4.3504E-07

-3.8877E-07

7

0.9995

5.0435E-04

1.9109E-03

4.4258E-05

-4.4525E-05

1.7721E-06

8

-4.4295

-3.3715E-04

-6.0810E-04

6.4116E-05

-6.7232E-06

4.3762E-07

9

-154.1956

3.7375E-03

-3.5237E-04

-3.8060E-06

5.0001E-06

-2.2438E-07

10

-11.2834

-3.2323E-03

5.5085E-04

-5.0510E-05

2.6860E-06

5.4848E-08

TABLE 9

R1(mm)	4.2032	SL(mm)	11.7711
				R2(mm)	2.0080	TTL(mm)	21.9999
d1(mm)	2.7046	ImgH(mm)	3.2872
				F2(mm)	8.0197	FOV(°)	45.0000
F(mm)	6.1708
				Nd2	1.7472

In the present embodiment, the on-axis distance SL from the stop STO to the imaging plane IMA and the total optical length TTL of the optical lens satisfy SL/TTL of 0.5351; R1/(R2+ d1) ═ 0.8919 among the radius of curvature R1 of the object-side surface S1 of the first lens L1, the radius of curvature R2 of the image-side surface S2 of the first lens L1, and the center thickness d1 of the first lens L1; F2/F1.2996 is satisfied between the focal length value F2 of the second lens L2 and the focal length value F of the entire group of optical lenses; the total optical length TTL of the optical lens and the whole group focal length value F of the optical lens meet the condition that TTL/F is 3.5652; the TTL/ImgH/FOV is 0.1487 between the total optical length TTL of the optical lens, the maximum half field angle FOV of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens; and F/ImgH is 1.8772 between the whole group focal length value F of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens.

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

Watch 10

Conditions/examples	1	2	3
				SL/TTL	0.5437	0.5090	0.5351
R1/(R2+d1)	0.9094	0.9687	0.8919
				F2/F	0.9333	1.0873	1.2996
TTL/F	3.3710	3.4393	3.5652
				TTL/ImgH/FOV	0.1064	0.1180	0.1487
F/ImgH	1.7358	1.7150	1.8772

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

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

Claims

1. An optical lens, wherein the number of the lenses having optical power is five, and the lenses are respectively a first lens, a second lens, a third lens, a fourth lens and a fifth lens, the first lens to the fifth lens are arranged in order from an object side to an image side along an optical axis,

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

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

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

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

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; and

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

the total optical length TTL of the optical lens, the maximum half field angle FOV of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens satisfy the following conditions: TTL/ImgH/FOV is less than or equal to 0.25.

2. An optical lens barrel according to claim 1, wherein the object side surface of the third lens is convex.

3. An optical lens barrel according to claim 1, wherein the object side surface of the third lens is a plane.

4. An optical lens barrel according to claim 1, wherein the object side surface of the third lens is concave.

5. An optical lens according to claim 1, wherein the third lens and the fourth lens are cemented to each other to form a cemented lens.

6. An optical lens according to claim 1, wherein the first lens, the third lens, the fourth lens and the fifth lens are all aspheric lenses.

7. An optical lens according to any one of claims 1 to 6, characterized in that a radius of curvature R1 of the object side surface of the first lens, a radius of curvature R2 of the image side surface of the first lens and a center thickness d1 of the first lens are satisfied: R1/(R2+ d1) 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 6, characterized in that the focal length value F2 of the second lens and the entire set of focal length values F of the optical lens satisfy: F2/F is more than or equal to 0.5 and less than or equal to 1.8.

9. An optical lens according to any one of claims 1 to 6, characterized in that the refractive index Nd2 of the optic of the second lens satisfies Nd2 ≧ 1.6.

10. An optical lens according to any one of claims 1 to 6, 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 4.5.

11. An optical lens according to any one of claims 1 to 6, wherein the entire group of focal length values F of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens satisfy: F/ImgH is more than or equal to 1.2.

12. An optical lens, wherein the number of the lenses having optical power is five, and the lenses are respectively a first lens, a second lens, a third lens, a fourth lens and a fifth lens, the first lens to the fifth lens are arranged in order from an object side to an image side along an optical axis,

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

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

the second lens and the fourth lens each have a positive optical power;

the third lens and the fourth lens are mutually glued to form a 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 meet the following conditions: TTL/F is less than or equal to 4.5;

13. An optical lens barrel according to claim 12, wherein the first lens element has a convex object-side surface and a concave image-side surface.

14. An optical lens barrel according to claim 12, wherein the object-side surface and the image-side surface of the second lens are convex.

15. An optical lens barrel according to claim 12, wherein the third lens element has a convex object-side surface and a concave image-side surface.

16. An optical lens barrel according to claim 12, wherein the object side surface of the third lens is a plane surface and the image side surface is a concave surface.

17. An optical lens barrel according to claim 12, wherein the object side surface and the image side surface of the third lens are both concave.

18. An optical lens barrel according to claim 12, wherein the object side surface and the image side surface of the fourth lens are convex.

19. An optical lens barrel according to claim 12, wherein the fifth lens element has a convex object-side surface and a concave image-side surface.

20. An optical lens barrel according to any one of claims 12 to 19, wherein the first lens, the third lens, the fourth lens and the fifth lens are aspherical mirror plates.

21. An optical lens barrel according to any one of claims 12 to 19, wherein the radius of curvature R1 of the object side surface of the first lens, the radius of curvature R2 of the image side surface of the first lens and the central thickness d1 of the first lens satisfy: R1/(R2+ d1) is more than or equal to 0.5 and less than or equal to 1.5.

22. An optical lens element according to any one of claims 12-19, characterized in that the focal length value F2 of the second lens element and the entire set of focal length values F of the optical lens element satisfy: F2/F is more than or equal to 0.5 and less than or equal to 1.8.

23. An optical lens element according to any of claims 12 to 19, characterized in that the refractive index Nd2 of the mirror plate of the second lens element satisfies Nd2 ≧ 1.6.

24. An optical lens as claimed in any one of claims 12 to 19, characterized in that the total set of focal length values F of the optical lens and the image height ImgH corresponding to the maximum half field angle of the optical lens satisfy: F/ImgH is more than or equal to 1.2.

25. An imaging apparatus comprising the optical lens of claim 1 or 12 and an imaging element for converting an optical image formed by the optical lens into an electric signal.