CN110501799B

CN110501799B - Optical lens

Info

Publication number: CN110501799B
Application number: CN201810466285.6A
Authority: CN
Inventors: 张野; 王东方; 姚波
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2018-05-16
Filing date: 2018-05-16
Publication date: 2022-03-11
Anticipated expiration: 2038-05-16
Also published as: CN110501799A

Abstract

The present application discloses an optical lens, which sequentially comprises, from an object side to an image side along an optical axis: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. 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 both the object side surface and the image side surface of the third lens are concave; the fourth lens can have positive focal power, and the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the fifth lens may have a positive optical power; and the sixth lens element can have a negative power, and the image-side surface of the sixth lens element is concave and the image-side surface of the sixth lens element is convex. According to the optical lens of the present application, at least one advantageous effect of miniaturization, long focal length, good temperature performance, and the like can be achieved.

Description

Optical lens

Technical Field

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

Background

With the development of science and technology, new technologies such as unmanned driving and the like are more and more popularized, and the requirement for remote imaging of the lens is higher and higher. The general vehicle-mounted lens requires a larger field of view, so that the focal length is smaller, and the long-distance clear imaging is not facilitated. The long-distance imaging requires a long focal length, but the long focal length results in a long overall length, which is not favorable for miniaturization of the lens, especially for an optical lens such as a vehicle-mounted lens with limited installation space.

At present, more and more fields need to use a lens for field expansion, and particularly under severe environments, the lens is more needed to replace human eyes for image acquisition and analysis. Therefore, the stability of the performance of the lens under different temperatures is important. In addition, in the general lens, when the temperature is increased or decreased, the optimal image plane of the lens shifts, and imaging blur occurs, so that high resolution at different temperatures also becomes a necessary performance of the forward-looking lens.

Disclosure of Invention

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

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

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

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

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

In one embodiment, a distance TTL between a center of an object side surface of the first lens element and an imaging surface of the optical lens on an optical axis and a full-group focal length value F of the optical lens may satisfy: TTL/F is less than or equal to 2.8.

In one embodiment, the variation of the refractive index of the material of the fifth lens with temperature can satisfy the requirement that dn/dt (5) is less than or equal to-5 x 10^-6。

In one embodiment, the object-side radius of curvature R12 of the sixth lens element and the image-side radius of curvature R13 thereof may satisfy: R12/R13 is more than or equal to 0.1 and less than or equal to 0.8.

In one embodiment, the refractive index Nd6 of the material of the sixth lens may be 1.65 or more.

Another aspect of the present application provides an optical lens that may include, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens, the third lens and the sixth lens can all have negative focal power; the second lens, the fourth lens and the fifth lens can all have positive focal power; the object side surface of the fifth lens can be a convex surface; and the distance TTL from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis 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 2.8.

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

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

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

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

In one embodiment, the image side surface of the fifth lens may be concave.

In another embodiment, the image-side surface of the fifth lens element can be convex.

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

This application has adopted six lenses for example, through the shape of optimizing the setting lens, the rational distribution of the focal power of each lens and lens etc. realize at least one beneficial effect such as optical lens's miniaturization, long focal length, temperature performance are good.

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; and

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

Detailed Description

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

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

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

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

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

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

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

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

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

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

The first lens element can have a negative power, and can have a convex object-side surface and a concave image-side surface. The first lens is arranged in a meniscus shape which is convex towards the object side, so that incident light can be collected as much as possible, and the light can be diffused after entering the optical system. In practical application, the vehicle-mounted lens outdoor installation and use environment is considered, the vehicle-mounted lens outdoor installation and use environment can be in severe weather such as rain and snow, the design of the meniscus shape protruding towards the object side is more suitable for the environments such as rain and snow, the water drops can slide off, and the influence of the external environment on imaging is 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 can converge the light collected by the first lens, so that the light is smoothly transited to the rear optical system.

The third 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 can disperse the light collected by the second lens, and the trend of the light is adjusted, so that the chromatic aberration is reduced.

The fourth lens element can have a positive power, and can have a concave object-side surface and a convex image-side surface. The fourth lens can converge the light passing through the front system, so that the light is smoothly transited to the fifth lens, and the total length of the system is favorably reduced.

The fifth lens element can have a positive optical power, and can have a convex object-side surface and a convex or concave image-side surface. The fifth lens can further converge the light collected by the fourth lens, adjust the light, enable the light trend to be stably transited to a rear optical system, and reduce the caliber of the rear end of the lens. In addition, the fifth lens is provided to have a positive power, and a change dn/dt (5) of a refractive index of a material with respect to a temperature change is a negative value, specifically, dn/dt (5) ≦ 5 × 10^-6This helps the lens to maintain a more perfect imaging sharpness over a larger temperature range.

The sixth lens element can have a negative power, and can have a concave object-side surface and a convex image-side surface. The sixth lens is a divergent lens and can diverge the front convergent light, so that the image light is in an ascending trend, and the matching of a large chip is realized. In addition, the sixth lens is set to have negative power and a limitation of a special shape of 0.1 ≦ R12/R13 ≦ 0.8 between its object-side curvature radius R12 and image-side curvature radius R13, and more desirably, 0.2 ≦ R12/R13 ≦ 0.6 is further satisfied between R12 and R13, and it is possible to further reduce the CRA and increase the focal length. The sixth lens can adopt a high refractive index material, for example, the refractive index of the sixth lens material satisfies Nd6 ≧ 1.65, and more ideally, further satisfies Nd6 ≧ 1.7, so as to further shorten TTL.

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. The diaphragm is arranged between the second lens and the third lens, can collect front and back light rays, reduces the aperture of the lens and achieves the effect of balancing the aperture of the front end and the rear end of the whole lens.

In an exemplary embodiment, TTL/F ≦ 2.8 may be satisfied between the total optical length TTL of the optical lens and the entire set of focal length values of the optical lens, and more desirably, TTL/F ≦ 2.5 may be further satisfied. The condition formula TTL/F is less than or equal to 2.8, and the miniaturization characteristic of the lens can be realized.

In an exemplary embodiment, the lens used in the optical lens may be a spherical lens or an aspherical lens. 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. When focusing on the resolution performance of the lens, the optical lens can adopt an aspheric lens to improve the resolution quality.

In an exemplary embodiment, the lens used in the optical lens may be a plastic lens, or may be a glass lens. The lens made of plastic has a large thermal expansion coefficient, and when the ambient temperature change of the lens is large, the lens made of plastic causes a large amount of change of the optical back focus of the lens. The glass lens can reduce the influence of temperature on the optical back focus of the lens. When focusing on the temperature performance of the lens, the optical lens can be made of all-glass materials so as to ensure that the optical performance is kept stable at different temperatures.

According to the optical lens of the above embodiment of the present application, the optical lenses are reasonably arranged to adjust the light so as to lengthen the focal length and ensure a shorter total length; through reasonable selection of lens materials, optimized setting of lens shapes and reasonable distribution of focal power, miniaturization of the lens is guaranteed, meanwhile, performance such as small distortion and high light passing performance are achieved, and the fact that the lens still keeps perfect imaging definition within a certain temperature range can be guaranteed.

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

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

Example 1

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

As shown in fig. 1, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6.

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

The second lens L2 is a 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 meniscus lens with positive power, with the object side S8 being concave and the image side S9 being convex.

The fifth lens L5 is a meniscus lens with positive power, with the object side S10 being convex and the image side S11 being concave.

The sixth lens L6 is a meniscus lens with negative power, and has a concave object-side surface S12 and a convex image-side surface S13.

Optionally, the optical lens may further include a filter L7 and/or a protective lens L7' having an object side S14 and an image side S15. Filter L7 can be used to correct for color deviations. The protective lens L7' 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 S15 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 second lens L2 and the third lens L3 to improve the imaging quality.

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

TABLE 1

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	12.0000	1.5000	1.52	64.21
2	4.5000	1.6000
					3	7.0000	3.0000	1.88	40.81
4	-200.0000	0.4000
					STO	All-round	0.8000
6	-25.0000	1.0000	1.85	23.79
					7	15.0000	0.8000
8	-15.0000	3.0000	1.88	40.81
					9	-6.5000	0.1700
10	6.3000	3.0000	1.50	81.55
					11	25.0000	1.2000
12	-9.0000	1.5000	1.85	23.79
					13	-20.0000	0.5600
14	All-round	0.9500	1.52	64.17
					15	All-round	2.4900
IMA	All-round

Table 2 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 image plane S16), the entire group focal length value F of the optical lens, the refractive index Nd6 of the material of the sixth lens L6, the variation dn/dt (5) of the refractive index with temperature of the material of the fifth lens L5, the radius of curvature R12 of the object-side surface S12 of the sixth lens L6, and the radius of curvature R13 of the image-side surface S13 thereof.

TABLE 2

Parameter(s)

F(mm)

TTL(mm)

Nd6

dn/dt(5)

R12(mm)

R13(mm)

Numerical value

9.509

21.970

1.85

-1.91×10^-5

-9.000

-20.000

In the present embodiment, TTL/F is 2.310 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; and the radius of curvature R12 of the object-side surface S12 of the sixth lens L6 and the radius of curvature R13 of the image-side surface S13 thereof satisfy R12/R13 of 0.450.

Example 2

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

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

The fifth lens L5 is a biconvex lens with positive optical power, and has both the object-side surface S10 and the image-side surface S11 convex.

Table 3 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 4 below gives the total optical length TTL of the optical lens of example 2 (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the image plane S16), the entire group focal length value F of the optical lens, the refractive index Nd6 of the material of the sixth lens L6, the variation dn/dt (5) of the refractive index with temperature of the material of the fifth lens L5, the radius of curvature R12 of the object-side surface S12 of the sixth lens L6, and the radius of curvature R13 of the image-side surface S13 thereof.

TABLE 3

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	10.0000	1.5000	1.52	64.21
2	5.0000	1.0000
					3	10.0000	2.0000	1.88	40.81
4	-200.0000	0.4000
					STO	All-round	0.8000
6	-15.0000	1.0000	1.85	23.79
					7	20.0000	0.8000
8	-20.0000	3.0000	1.88	40.81
					9	-7.0000	0.1700
10	6.3000	3.0000	1.50	81.55
					11	-30.0000	1.2000
12	-8.5000	1.5000	1.85	23.79
					13	-24.0000	0.5600
14	All-round	0.9500	1.52	64.17
					15	All-round	4.1677
IMA	All-round

TABLE 4

Parameter(s)

F(mm)

TTL(mm)

Nd6

dn/dt(5)

R12(mm)

R13(mm)

Numerical value

9.497

22.048

1.85

-1.91×10^-5

-8.500

-24.000

In the present embodiment, TTL/F is 2.322 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; and the radius of curvature R12 of the object-side surface S12 of the sixth lens L6 and the radius of curvature R13 of the image-side surface S13 thereof satisfy that R12/R13 is 0.354.

In summary, examples 1 to 2 each satisfy the relationship shown in table 5 below.

TABLE 5

Conditions/examples	1	2
			TTL/F	2.310	2.322
R12/R13	0.450	0.354

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

Claims

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

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

the first lens has 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 both the object side surface and the image side surface of the third lens are concave;

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

the fifth lens has positive focal power;

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

the distance TTL from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis and the whole group of focal length values F of the optical lens satisfy the following conditions: TTL/F is less than or equal to 2.8;

the object side curvature radius R12 and the image side curvature radius R13 of the sixth lens meet the following condition: R12/R13 is more than or equal to 0.2 and less than or equal to 0.8; and

the number of the lenses of the optical lens with focal power is six.

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

3. An optical lens barrel according to claim 1, wherein the object-side surface and the image-side surface of the fifth lens element are convex.

4. An optical lens according to claim 1, further comprising a diaphragm disposed between the second lens and the third lens.

5. An optical lens barrel according to any one of claims 1 to 4, wherein the fifth lens has a material refractive index whose amount of change with temperature satisfies dn/dt (5) ≦ 5 x 10^-6。

6. An optical lens according to any one of claims 1 to 4, characterized in that the refractive index Nd6 of the material of the sixth lens is equal to or greater than 1.65.

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

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

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

the second lens, the fourth lens and the fifth lens each have positive optical power;

the object side surface of the fifth lens is a convex surface;

the distance TTL from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis and the whole group of focal length values F of the optical lens satisfy the following condition: TTL/F is less than or equal to 2.8;

the number of the lenses of the optical lens with focal power is six.

8. An optical lens barrel according to claim 7, wherein the object side surface of the first lens element is convex and the image side surface of the first lens element is concave.

9. An optical lens barrel according to claim 7, wherein the object-side surface and the image-side surface of the second lens are convex.

10. An optical lens barrel according to claim 7, wherein the object side surface and the image side surface of the third lens are both concave.

11. An optical lens barrel according to claim 7, wherein the fourth lens element has a concave object-side surface and a convex image-side surface.

12. An optical lens barrel according to claim 7, wherein the image side surface of the fifth lens element is concave.

13. An optical lens barrel according to claim 7, wherein the image side surface of the fifth lens element is convex.

14. An optical lens barrel according to claim 7, wherein the sixth lens element has a concave object-side surface and a convex image-side surface.

15. An optical lens barrel according to any one of claims 7 to 14, further comprising a diaphragm disposed between the second lens and the third lens.

16. An optical lens according to any one of claims 7 to 14, characterized in that the refractive index Nd6 of the material of the sixth lens is 1.65 or more.

17. An optical lens barrel according to any one of claims 7 to 14, wherein the fifth lens has a material refractive index whose amount of change with temperature satisfies dn/dt (5) ≦ 5 x 10^-6。