CN109597189B - Optical lens - Google Patents

Abstract

The present application discloses an optical lens, which sequentially comprises, from an object side to an image side along an optical axis: the lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, wherein the first lens has negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens has a negative optical power; the third lens has positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens has negative focal power, and the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface; the fifth lens has positive focal power, and the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface.

Description

Optical lens

Technical Field

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

Background

At present, imaging performances under different temperature performances are more and more concerned about the vehicle-mounted wide-angle lens, and a high-definition imaging state can still be hopefully maintained in different temperature variation ranges. In order to achieve megapixel definition, a 6-piece or 5-piece optical system is often used in the current wide-angle lens, wherein plastic lenses are mostly used to achieve the effects of cost reduction and portability. 4 plastic aspheric lenses are usually adopted in a 5-piece system to be plasticized to the maximum extent and meet the requirements of high resolution and low cost.

However, since the expansion with heat and contraction with cold characteristics of the plastic lens are difficult to overcome, although the temperature performance of the lens is better realized by the collocation of the focal power of the lens and the selection of the material, the whole lens still cannot meet the increasingly severe temperature requirement, so that the 6-piece structural scheme of the glass lens with stable temperature performance, which at least comprises 2 glass lenses, is gradually and widely proposed. The 6-piece structure can improve the imaging quality on one hand, and can compensate the high-temperature back focus offset caused by multiple plastic lenses on the other hand, but the increase of the lenses inevitably causes the cost to rise.

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, in order from an object side to an image side along an optical axis, comprising: the lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens, wherein the first lens has negative focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens has a negative optical power; the third lens has positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens has negative focal power, and the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface; the fifth lens has positive focal power, and the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface.

In one embodiment, the optical lens further includes a stop disposed between the third lens and the fourth lens.

In one embodiment, the fourth lens and the fifth lens are cemented to form a cemented lens.

In one embodiment, the second lens is concave at the center of the object side surface and concave at the center of the image side surface, and the second lens has at least one point of inflection.

In one embodiment, the opening angle of the second lens image side surface S4 satisfies arctan (SAG (S4)/d (S4)) ≦ 70 °.

In one embodiment, the opening angle of the bonding surface S9 where the fourth lens and the fifth lens are bonded to each other satisfies arctan (SAG (S9)/d (S9)) ≦ 70 °.

In one embodiment, an opening angle of the cemented surface S9 where the fourth lens and the fifth lens are cemented with each other satisfies 35 ≦ arctan (SAG (S9)/d (S9)) ≦ 66.

In one embodiment, the first lens and the third lens are glass lenses, and the second lens, the fourth lens and the fifth lens are plastic lenses.

In one embodiment, the refractive index Nd1 ≧ 1.7 of the first lens material.

In one embodiment, the refractive index Nd4 of the fourth lens material is greater than or equal to 1.6.

In one embodiment, BFL/TTL is more than or equal to 0.1 between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens.

In one embodiment, the difference between the focal length value F2 of the second lens element of the optical lens and the focal length value F of the lens group of the optical lens located behind the stop satisfies | F2/F rear | ≦ 0.8.

In one embodiment, the focal length value F2 of the second lens of the optical lens and the focal length value F5 of the fifth lens of the optical lens meet F2/F5 ≦ -1.6.

In one embodiment, the focal length value F3 of the third lens of the optical lens and the focal length value F4 of the fourth lens of the optical lens meet the condition that F3/F4 is less than or equal to-2.1.

In one embodiment, the optical lens satisfies-8 ≦ Fpre/F ≦ 7 between the focal length value Fpre of the lens group located in front of the diaphragm and the entire group focal length value F of the optical lens.

In one embodiment, the optical lens has a back focus offset of < 0.02mm in a temperature range of-40 ℃ to 105 ℃.

Another aspect of the present disclosure provides an optical lens, in order from an object side to an image side along an optical axis: a first lens with negative focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power and a fifth lens with positive focal power, wherein the second lens has at least one inflection point, and the opening angle of the second lens image side surface S4 satisfies arctan (SAG (S4)/d (S4)) ≦ 70 degrees, wherein d (S4) is a half aperture of the maximum clear aperture of the second lens image side surface S4 corresponding to the maximum field angle of the optical lens, and SAG is a value of Sg corresponding to the second lens image side surface S4; and the fourth lens and the fifth lens are cemented to constitute a cemented lens.

The optical lens mainly adopts a 5-piece structure, at least adopts 2 glass lenses (2G3P), and compared with a conventional 5-piece structure (1G4P) adopting 4 plastic lenses, the temperature performance is greatly improved; by further revealing the specific material collocation and the limitation requirement of the lens shape, compared with a lens (2G3P) with the same structure, the imaging performance is improved, and the conventional similar 6-piece structural scheme (2G4P) can be approached.

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 shows a SAG representation of a lens mirror, which schematically shows a calculation method of SAG of the lens mirror.

Detailed Description

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

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

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

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

It will be further understood that the terms "comprises," "comprising," "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 second lens element can have a negative optical power, and can have a concave object-side surface and a concave image-side surface.

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

The fourth lens element can have a negative power, and can have a convex object-side surface and a concave image-side surface.

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

In an exemplary embodiment, the first lens is a meniscus lens, which is an arrangement that is capable of collecting as large a field of view as possible and passing the collected light into the posterior optical system. The first lens is arranged with a convex surface facing the object side. In practical application, the vehicle-mounted lens installed outdoors is often subjected to severe weather such as rain, snow and the like, and the first lens is arranged as the meniscus lens with the convex surface facing the object side, so that water drops falling on the lens can slide off, and the influence on imaging is reduced. The first lens can be a glass lens, which is beneficial to enhancing the performances of scratch resistance, abrasion resistance, corrosion resistance and the like of the optical lens and is beneficial to the temperature stability of the lens. Furthermore, the first lens can adopt a glass aspheric surface to further improve the imaging quality of the optical lens and reduce the front end caliber. The first lens can adopt a high-refractive-index material (Nd1 is more than or equal to 1.7), which is beneficial to reducing the front end aperture and improving the imaging quality.

In an exemplary embodiment, the center of the second lens may be biconcave in shape and the second lens has at least one inflection point, which facilitates reducing the optic aperture of the second lens. The peripheral inflected shape of the second lens object-side surface S3 is matched with the larger opening angle of the second lens image-side surface S4, so that peripheral light rays can be smoothly transited to the rear side. In an exemplary embodiment, the focal length F2 of the second lens is limited and the focal lengths of the lenses are reasonably distributed, which is beneficial for achieving perfect image resolution of the lens in a large temperature range and enabling the lens to achieve good temperature stability.

In an exemplary embodiment, the third lens is a biconvex lens, and can converge light rays, so that light rays diverged at the front end are converged to the rear quickly.

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 fourth lens and the fifth lens may be combined into a cemented lens by cementing the image-side surface of the fourth lens with the object-side surface of the fifth lens. In the cemented lens, the fourth lens close to the object side has negative focal power, the fifth lens close to the image side has positive focal power, and by the arrangement, the light rays converged by the front-end third lens are firstly diverged and transited, then the phase difference is further corrected by the fifth lens with positive focal power, and the converged light rays reach the image surface. Through introducing the cemented lens who comprises fourth lens and fifth lens, can be favorable to the realization of large aperture, simultaneously, because the increase of cemented surface field angle is favorable to peripheral light to focus fast, improves imaging quality.

Further, the configuration of the cemented lens can omit the air space between each lens in the cemented lens, so that the optical system is compact as a whole and meets the requirement of system miniaturization. Furthermore, the gluing of the lenses reduces tolerance sensitivity problems of the lens units due to tilt/decentration during assembly.

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, incident light rays can be contracted, the calibers of the front lens group and the rear lens group of the lens can be reduced, the total length of an optical system can be shortened, and the miniaturization characteristic can be realized.

In an exemplary embodiment, the first lens and the third lens are glass lenses, and the second lens, the fourth lens and the fifth lens are plastic lenses, so that the material matching arrangement can improve the performance of the lens.

In an exemplary embodiment, the opening angle of the second lens image side S4 satisfies arctan (SAG (S4)/d (S4)) ≦ 70 °. More specifically, the opening angle of the image side surface S4 of the second lens satisfies arctan (SAG (S4)/d (S4)) ≦ 58 °. The field angle setting can optimize peripheral light rays, improve the imaging quality of the lens and meet the manufacturing requirement.

In an exemplary embodiment, the opening angle of the cemented face satisfies arctan (SAG (S9)/d (S9)) ≦ 70 °.

In an exemplary embodiment, the opening angle of the cemented face satisfies 35 ≦ arctan (SAG (S9)/d (S9)) ≦ 66 °. More specifically, the opening angle of the cemented surface satisfies 40 DEG.ltoreq.arctan (SAG (S9)/d (S9)). ltoreq.63 deg.

In an exemplary embodiment, the refractive index Nd1 ≧ 1.7 of the optical lens first lens material. More specifically, the refractive index Nd1 of the first lens material of the optical lens is equal to or greater than 1.77.

In an exemplary embodiment, the refractive index Nd4 ≧ 1.6 of the fourth lens material of the optical lens. More specifically, the refractive index Nd4 of the fourth lens material of the optical lens is larger than or equal to 1.64.

In an exemplary embodiment, a distance between an optical back focus BFL (i.e., a distance from a center of an image side surface of a last lens to an image plane) of the optical lens and an optical total length TTL (i.e., a distance from a center of an object side surface of a first lens to an image plane of the optical lens on an optical axis) of the optical lens satisfies that BFL/TTL is greater than or equal to 0.1. More specifically, the BFL/TTL ratio between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens is more than or equal to 0.19. This back focus arrangement facilitates assembly in view of the overall architecture of the optical lens.

In an exemplary embodiment, the difference between the focal length value F2 of the second lens element of the optical lens and the focal length value F of the lens group of the optical lens located behind the stop satisfies | F2/F rear | ≦ 0.8. More specifically, the focal length value F2 of the second lens element of the optical lens and the focal length value F rear of the lens group of the optical lens behind the stop satisfy | F2/F rear ≦ 0.67.

In an exemplary embodiment, a focal length value F2 of the second lens of the optical lens and a focal length value F5 of the fifth lens of the optical lens satisfy F2/F5 ≦ -1.6. More specifically, the focal length value F2 of the second lens of the optical lens and the focal length value F5 of the fifth lens of the optical lens meet F2/F5 ≦ -1.76.

In an exemplary embodiment, a focal length value F3 of the third lens of the optical lens and a focal length value F4 of the fourth lens of the optical lens satisfy F3/F4 ≦ -2.1. More specifically, the focal length value F3 of the third lens of the optical lens and the focal length value F4 of the fourth lens of the optical lens meet F3/F4 ≦ -2.38.

In an exemplary embodiment, before the focal length value Ffront of the lens group of the optical lens positioned in front of the diaphragm and the whole group focal length value F of the optical lens satisfy-8 ≦ Ffront/F ≦ 7. More specifically, the focal length value Ffront of the lens group of the optical lens positioned in front of the diaphragm and the whole group focal length value F of the optical lens satisfy that F front/F is more than or equal to-5 and less than or equal to 2.29.

In practical use, due to temperature change, the curvature, thickness and refractive index of the lens change, which results in the shift of the best imaging plane, and the shift is the back focus shift (also called defocus) of the optical system. The optical lens has the advantages that the offset of the back focus is less than 0.02mm within the temperature range of-40-105 ℃, and the optical lens has strong temperature stability.

The reasonable distribution of the focal power of each lens of the optical lens, especially the focal power of the second lens, the fourth lens and the fifth lens is beneficial to reducing the overall thermal compensation of the system.

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 biconcave lens with negative power, and has a concave object-side surface S3 and a concave image-side surface S4.

The third lens L3 is a biconvex lens with positive power, and has a convex object-side surface S5 and a convex image-side surface S6.

The fourth lens L4 is a meniscus lens with negative power, with the object side S8 being convex and the image side S9 being concave.

The fifth lens element L5 is a biconvex lens with positive power, and has a convex object-side surface S9 and a convex image-side surface S10.

Wherein, the fourth lens L4 and the fifth lens L5 are cemented to form a cemented lens.

Optionally, the optical lens may further include a filter L6 having an object-side surface S11 and an image-side surface S12 and/or a protective lens L7 having an object-side surface S13 and an image-side surface S14. Filters may be used to correct for color deviations. The protective lens may be used to protect the image sensing chip located at the imaging surface S15. The light from the object sequentially passes through the respective surfaces S1 to S14 and is finally imaged on the imaging surface S15.

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

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

TABLE 1

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	10.0000	0.8456	1.80	45.00
2	1.5277	1.9801
					3	-4.6410	0.9909	1.51	56.29
4	1.4749	1.0201
					5	10.9485	1.5523	1.90	21.00
6	-5.0246	0.8063
					STO	Infinity	0.2014
8	3.0000	0.5340	1.65	21.00
					9	0.7063	1.4104	1.54	55.78
10	-1.7901	0.0668
					11	Infinity	0.5500	1.52	64.21
12	Infinity	1.0020
					13	Infinity	0.4000	1.52	64.21
14	Infinity	1.8977
					IMA	Infinity

In the embodiment, five lenses are taken as an example, and by reasonably distributing the focal power and the surface type of each lens, the central thickness of each lens and the air space between the lenses, the lens can realize the effects of reducing the total optical length and the lens aperture while ensuring large imaging size and high pixels. Each aspherical surface type Z is defined by the following formula:

wherein Z is the distance rise from the vertex of the aspheric surface when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is the conic coefficient conc; A. b, C, D, E are all high order term coefficients. Table 2 below shows cone coefficients k and high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S8, S9, and S10 in example 1.

TABLE 2

Flour mark

K

A

B

C

D

E

3

-80.0000

3.3838E-02

-1.1007E-02

1.7198E-03

-2.5129E-04

5.7546E-05

4

-0.5264

1.4568E-01

-7.6362E-02

3.4456E-02

-1.3740E-03

2.3392E-05

8

-1.2255

-5.8693E-03

-1.6620E-02

1.1128E-01

-4.6957E-01

3.6531E-01

9

-0.9827

1.5570E-01

-2.8138E-01

2.5775E-01

-7.3315E-02

1.1344E-01

10

-7.7084

-8.3954E-02

7.0975E-02

-7.9971E-03

-8.3927E-03

2.2400E-04

Table 3 below shows the focal length value F1 of the first lens, the focal length value F2 of the second lens, the focal length value F3 of the third lens, the focal length value F4 of the fourth lens, the focal length value F5 of the fifth lens, the focal length value F of the lens group of the optical lens behind the stop, the focal length value F of the lens group of the optical lens in front of the stop, and the entire group focal length value F of the optical lens of example 1. Table 4 below shows the optical back focus BFL of the optical lens, the total optical length TTL of the optical lens (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface S15), the maximum field angle FOV of the optical lens, the refractive index Nd1 of the first lens material of the optical lens, and the refractive index Nd4 of the fourth lens material of the optical lens.

TABLE 3

	F1	F2	F3	F4	F5	F after	F front	F
									E1	-2.346	-2.064	3.968	-1.548	1.174	3.092	-3.640	0.729

TABLE 4

	BFL	TTL	FOV	Nd1	Nd4
						E1	3.92	13.26	150	1.80	1.64

In this embodiment, a BFL/TTL between an optical back focus BFL of the optical lens and an optical total length TTL of the optical lens is 0.30; the focal length value F2 of the second lens of the optical lens and the focal length value F back of the lens group of the optical lens behind the diaphragm satisfy | F2/F back | -0.67; F2/F5 is-1.76 between the focal length value F2 of the second lens of the optical lens and the focal length value F5 of the fifth lens of the optical lens; F3/F4 is-2.56 between the focal length value F3 of the third lens and the focal length value F4 of the fourth lens; the focal length value F of the lens group of the optical lens positioned in front of the diaphragm and the focal length value F of the whole group of the optical lens meet the condition that F front/F is equal to-5.00.

In this embodiment, the opening angle of the second lens image-side surface S4 satisfies arctan (SAG (S4)/d (S4)) -37 °, where d (S4) is the half aperture of the maximum clear aperture of the second lens image-side surface S4 corresponding to the maximum field angle of the optical lens, and SAG is the Sg value corresponding to the second lens image-side surface S4 (SAG calculation is shown in fig. 3).

In this embodiment, the opening angle of the bonding surface S9 satisfies arctan (SAG (S9)/d (S9)) -63 °, where d (S9) is the half aperture of the maximum clear aperture of the bonding surface S9 of the fourth lens and the fifth lens corresponding to the maximum field angle of the optical lens, and SAG (S9) is the Sg value corresponding to the bonding surface S9 (SAG calculation is shown in fig. 3).

Examples2

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 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 power, and has a concave object-side surface S3 and a concave image-side surface S4.

The third lens L3 is a biconvex lens with positive power, and has a convex object-side surface S5 and a convex image-side surface S6.

The fourth lens L4 is a meniscus lens with negative power, with the object side S8 being convex and the image side S9 being concave.

The fifth lens element L5 is a biconvex lens with positive power, and has a convex object-side surface S9 and a convex image-side surface S10.

Wherein, the fourth lens L4 and the fifth lens L5 are cemented to form a cemented lens.

Optionally, the optical lens may further include a filter L6 having an object-side surface S11 and an image-side surface S12 and/or a protective lens L7 having an object-side surface S13 and an image-side surface S14. Filters may be used to correct for color deviations. The protective lens may be used to protect the image sensing chip located at the imaging surface S15. The light from the object sequentially passes through the respective surfaces S1 to S14 and is finally imaged on the imaging surface S15.

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

Table 5 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 6 below shows cone coefficients k and high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S3, S4, S8, S9, and S10 in example 2. Table 7 below gives the focal length value F1 of the first lens, the focal length value F2 of the second lens, the focal length value F3 of the third lens, the focal length value F4 of the fourth lens, the focal length value F5 of the fifth lens, and the focal length value F of the entire group of optical lenses before the focal length value F of the group of optical lenses before the stop after the focal length value F of the group of optical lenses after the stop in the optical lens of example 2. Table 8 below shows the optical back focus BFL of the optical lens, the total optical length TTL of the optical lens (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface S15), the maximum field angle FOV of the optical lens, the refractive index Nd1 of the first lens material of the optical lens, and the refractive index Nd4 of the fourth lens material of the optical lens. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

TABLE 5

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	13.0000	0.8000	1.77	49.61
2	3.0448	2.2677
					3	-27.6147	0.7375	1.55	56.29
4	1.3342	1.7923
					5	3.8602	2.0000	1.85	23.79
6	-3.8602	-0.0225
					STO	Infinity	0.1688
8	5.5119	0.6000	1.64	23.53
					9	0.5926	1.7000	1.57	56.00
10	-1.8695	0.1054
					11	Infinity	0.5500	1.52	64.21
12	Infinity	1.1860
					13	Infinity	0.4000	1.52	64.21
14	Infinity	0.1503
					IMA	Infinity

TABLE 6

TABLE 7

	F1	F2	F3	F4	F5	F after	F front	F
									E2	-5.309	-2.284	2.563	-1.079	1.050	3.426	1.871	0.818

TABLE 8

	BFL	TTL	FOV	Nd1	Nd4
						E2	2.39	12.44	150	1.77	1.64

In this embodiment, a BFL/TTL between an optical back focus BFL of the optical lens and an optical total length TTL of the optical lens is 0.19; the focal length value F2 of the second lens of the optical lens and the focal length value F back of the lens group of the optical lens behind the diaphragm satisfy | F2/F back | -0.67; F2/F5 is-2.17 between the focal length value F2 of the second lens of the optical lens and the focal length value F5 of the fifth lens of the optical lens; F3/F4 is-2.38 between the focal length value F3 of the third lens and the focal length value F4 of the fourth lens; the focal length value F of the lens group of the optical lens positioned in front of the diaphragm and the focal length value F of the whole group of the optical lens meet that F front/F is 2.29; the opening angle of the second lens image side surface S4 satisfies arctan (SAG (S4)/d (S4)) ═ 58 °; the opening angle of the bonding surface S9 satisfies arctan (SAG (S9)/d (S9)) ═ 40 degrees.

In summary, example 1 and example 2 satisfy the relationships shown in the following table 9 and table 10, respectively.

TABLE 9

Conditional expression (A) example	E1	E2
			BFL/TTL	0.30	0.19
I F2/F	0.67	0.67
			F2/F5	-1.76	-2.17
F3/F4	-2.56	-2.38
			F front/F	-5.00	2.29

Watch 10

arctan(SAG/d)(°)	E1	E2
			L2-S2(S4)	37	58
L4-S2/L5-S1(S9)	63	40

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 (26)

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

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

the first lens has 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 has a negative optical power;

the third lens has positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface;

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

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

wherein the focal length value F2 of the second lens of the optical lens and the focal length value F5 of the fifth lens of the optical lens meet F2/F5 ≦ -1.6;

the focal length value F of the lens group of the optical lens positioned in front of the diaphragm and the focal length value F of the whole group of the optical lens meet the condition that F front/F is more than or equal to-8 and less than or equal to 7; and

the number of lenses with focal power in the optical lens is five.

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

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

4. An optical lens as recited in claim 1, wherein the second lens is concave at the center of the object side and concave at the center of the image side, and the second lens has at least one inflection point.

5. An optical lens according to any one of claims 1 to 3, wherein the field angle of the second lens image-side surface S4 satisfies arctan (SAG (S4)/d (S4)) ≦ 70 °, wherein d (S4) is the half aperture of the maximum clear aperture of the second lens image-side surface S4 corresponding to the maximum field angle of the optical lens, and SAG is the value of Sg corresponding to the second lens image-side surface S4.

6. An optical lens according to any one of claims 1 to 4, wherein an opening angle of a cemented surface S9 where the fourth lens and the fifth lens are cemented with each other satisfies arctan (SAG (S9)/d (S9)) ≦ 70 °, where d (S9) is a half aperture of a maximum clear aperture of cemented surfaces S9 of the fourth lens and the fifth lens corresponding to a maximum field angle of the optical lens, and SAG (S9) is a value of Sg corresponding to the cemented surface S9.

7. An optical lens according to claim 6, wherein an opening angle of a cemented surface S9 where the fourth lens and the fifth lens are cemented with each other satisfies 35 ° ≦ arctan (SAG (S9)/d (S9)) ≦ 66 °.

8. An optical lens according to any one of claims 1 to 4, characterized in that the first lens and the third lens are glass optics and the second lens, the fourth lens and the fifth lens are plastic optics.

9. An optical lens according to claim 8, characterized in that the refractive index Nd1 ≧ 1.7 of the first lens material.

10. An optical lens according to any of claims 1 to 4, characterized in that the refractive index Nd4 ≧ 1.6 of the fourth lens material.

11. An optical lens according to any one of claims 1 to 4, characterized in that BFL/TTL ≥ 0.1 is satisfied between an optical back focus BFL of the optical lens and an optical total length TTL of the optical lens.

12. An optical lens element according to any one of claims 1-4, characterized in that the focal length value F2 of the second lens element of the optical lens element satisfies | F2/F rear | ≦ 0.8 between the focal length value F2 of the second lens element of the optical lens element situated behind the stop.

13. An optical lens according to any one of claims 1 to 4, characterized in that a value of the focal length of the third lens of the optical lens, F3, and a value of the focal length of the fourth lens of the optical lens, F4, satisfy F3/F4 ≦ -2.1.

14. An optical lens according to any one of claims 1 to 4, characterized in that the optical lens has a back focus offset < 0.02mm in a temperature range of-40 ℃ to 105 ℃.

15. The optical lens sequentially comprises from an object side to an image side along an optical axis: a first lens having a negative power, a second lens having a negative power, a third lens having a positive power, a fourth lens having a negative power, and a fifth lens having a positive power,

the second lens is characterized in that the second lens is provided with at least one inflection point, and the opening angle of the second lens image side surface S4 meets the requirement that arctan (SAG (S4)/d (S4)). ltoreq.70 degrees, wherein d (S4) is the half aperture of the maximum clear aperture of the second lens image side surface S4 corresponding to the maximum field angle of the optical lens, and SAG is the value of Sg corresponding to the second lens image side surface S4;

the fourth lens and the fifth lens are cemented to form a cemented lens,

wherein the focal length value F2 of the second lens of the optical lens and the focal length value F5 of the fifth lens of the optical lens meet F2/F5 ≦ -1.6;

the focal length value F of the lens group of the optical lens positioned in front of the diaphragm and the focal length value F of the whole group of the optical lens meet the condition that F front/F is more than or equal to-8 and less than or equal to 7; and

the number of lenses with focal power in the optical lens is five.

16. The optical lens according to claim 15,

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 object side surface of the second lens is a concave surface, and the image side surface of the second lens is a concave surface;

the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface;

the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface; and

the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface.

17. The optical lens of claim 16, wherein an opening angle of a cemented surface S9 where the fourth lens and the fifth lens are cemented with each other satisfies arctan (SAG (S9)/d (S9)) ≦ 70 °, wherein d (S9) is a half aperture of a maximum clear aperture of the cemented surface S9 of the fourth lens and the fifth lens corresponding to a maximum field angle of the optical lens, and SAG (S9) is a Sg value corresponding to the cemented surface S9.

18. An optical lens according to claim 17, wherein an opening angle of a cemented surface S9 where the fourth lens and the fifth lens are cemented with each other satisfies 35 ° ≦ arctan (SAG (S9)/d (S9)) ≦ 66 °.

19. An optical lens according to claim 15, characterized in that the first lens and the third lens are glass optics and the second lens, the fourth lens and the fifth lens are plastic optics.

20. An optical lens according to any one of claims 15 to 19, characterized in that the refractive index Nd1 ≧ 1.7 of the first lens material.

21. An optical lens according to any one of claims 15 to 19, characterized in that the refractive index Nd4 ≧ 1.6 of the fourth lens material.

22. An optical lens according to any one of claims 15 to 19, characterized in that BFL/TTL ≥ 0.1 is satisfied between an optical back focus BFL of the optical lens and an optical total length TTL of the optical lens.

23. An optical lens element according to any one of claims 15 to 19, characterized in that the focal length value F2 of the second lens element of the optical lens element satisfies | F2/F rear | ≦ 0.8 between the focal length value F2 of the second lens element of the optical lens element located behind the stop.

24. An optical lens according to any one of claims 15 to 19, characterized in that F3/F4 ≦ -2.1 is satisfied between the focal length value F3 of the third lens of the optical lens and the focal length value F4 of the fourth lens of the optical lens.

25. An optical lens according to any one of claims 15 to 19, characterized in that the optical lens further comprises a diaphragm disposed between the third lens and the fourth lens.

26. An optical lens according to claim 15, characterized in that the back focus offset of the optical lens is < 0.02mm in the temperature range-40 ℃ to 105 ℃.

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