CN111198430B

CN111198430B - Optical lens and imaging apparatus

Info

Publication number: CN111198430B
Application number: CN201811373609.8A
Authority: CN
Inventors: 张野
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2018-11-19
Filing date: 2018-11-19
Publication date: 2022-02-08
Anticipated expiration: 2038-11-19
Also published as: CN111198430A

Abstract

The application discloses an optical lens and an imaging apparatus. The optical lens may include, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens has positive focal power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; the second lens has negative focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the third lens has negative focal power, and both the object side surface and the image side surface of the third lens are concave surfaces; the fourth lens has positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces; the fifth lens has negative focal power, 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 sixth lens has positive focal power, and both the object side surface and the image side surface of the sixth lens are convex surfaces; and the seventh lens may have a positive optical power. According to the optical lens, at least one of the beneficial effects of miniaturization, small CRA, large aperture, long back focal length, low cost, good temperature performance, long-distance imaging and the like can be realized.

Description

Optical lens and imaging apparatus

Technical Field

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

Background

With the development of scientific technology and the wide application of high and new technology, the automobile auxiliary driving technology is gradually developed and matured, and the optical lens is more and more widely applied to automobiles. Meanwhile, more and more companies begin to research the automatic driving lens, and the performance requirement of the optical lens for vehicle-mounted application is very high, while the performance requirement of the optical lens for automatic driving is more strict.

The requirement of the automatic driving lens on the long-distance imaging of the lens is higher and higher, the long-distance imaging needs the longer focal length of the lens, but the longer focal length can cause the longer total length of the lens, and the miniaturization of the lens is not facilitated. An optical lens with a limited installation space, particularly an in-vehicle lens; meanwhile, such optical lenses require a larger aperture to realize clear recognition of a low-light environment. Generally, such optical lenses have high requirements on stray light, and a smaller Chief Ray Angle (CRA) is required to avoid stray light generated when the rear end of the ray is emitted and hits on the lens barrel. In particular, in more and more fields, a lens is required to be used for field expansion, and particularly, in a severe environment, the lens is required to be used for collecting and analyzing images instead of human eyes, so that it is important that the lens can maintain stable performance at different temperatures.

Therefore, there is a need for an optical lens with a long focal length, which is compact and low in cost, and can be used in low light and severe environments.

Disclosure of Invention

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

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

In one embodiment, the object-side surface of the seventh 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 seventh lens element can be convex.

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

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

In one embodiment, each of the first to seventh lenses may be a glass lens.

In one embodiment, the total optical length TTL of the optical lens and the entire focal length F of the optical lens may satisfy: TTL/F is less than or equal to 4.5.

In one embodiment, the optical back focus BFL of the optical lens and the lens group length TL of the optical lens may satisfy: BFL/TL is more than or equal to 0.2.

In one embodiment, the focal length values F of the entire group of the optical lens and F1 of the first lens satisfy: F/F1 is not less than 0.15.

In one embodiment, the change dn/dt of the refractive index of the material of the seventh lens with temperature change can be a negative value.

Another aspect of the present application provides an optical lens that may include, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens, the fourth lens, the sixth lens and the seventh lens all have positive focal power; the second lens, the third lens and the fifth lens may each have a negative focal power; the third lens and the fourth lens may be cemented with each other to form a first cemented lens; the fifth lens and the sixth lens may be cemented with each other to form a second cemented lens; and the total optical length TTL of the optical lens and the whole group of focal length values F of the optical lens can meet the following requirements: TTL/F is less than or equal to 4.5.

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, the object-side surface of the second 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 third lens can be concave.

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

In one embodiment, each of the first to seventh lenses may be a glass lens.

In one embodiment, the change dn/dt (7) of the refractive index of the material of the seventh lens with temperature change can be a negative value.

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

The optical lens adopts seven lenses, the focal power of each lens is reasonably distributed and the cemented lens is formed by optimally setting the shape of the lenses, so that at least one of the beneficial effects of miniaturization, small CRA (crap), large aperture, long back focal length, low cost, good temperature performance, long-distance imaging and the like of the optical lens is realized.

Drawings

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

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

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

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

fig. 4 is a schematic view showing a structure of an optical lens according to embodiment 4 of the present application.

Detailed Description

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

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

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

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

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

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

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

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

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

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

The first lens element can have a positive power, and can have a convex object-side surface and a concave image-side surface. The first lens is arranged in a meniscus shape with the convex surface facing the object side, so that light with a large field of view can be collected as far as possible, the light enters a rear optical system, and the light flux is increased. In practical application, the lens is installed and used outdoors, so that the lens can be in severe weather such as rain, snow and the like, and the design of the meniscus shape with the convex surface facing the object side is more suitable for environments such as rain, snow and the like, is favorable for water drop sliding, is not easy to accumulate water and dust, and reduces the influence of the external environment on imaging.

The second lens element can have a negative power, and can have a convex object-side surface and a concave image-side surface. The second lens can disperse the light passing through the front first lens, so that the light can be adjusted and the aberration can be reduced.

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 further diffuse the light rays diffused by the second lens in front and then transition the light rays into the rear optical system, so that the light inlet quantity of the rear optical system is increased.

The fourth lens element can have a positive optical power, and can have a convex object-side surface and a convex image-side surface. The fourth lens can quickly converge the light rays diffused by the third lens in front and then transition the light rays to a rear optical system, so that the optical path of the rear light rays can be reduced, and the short TTL can be realized.

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

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

The seventh lens element can have a positive optical power, and can have a convex object-side surface and a convex or concave image-side surface. The seventh lens can further converge the light collected by the sixth lens, adjust the light, enable the light to stably reach the imaging surface, and further reduce the CRA. The seventh lens is arranged to have positive focal power, and the variation dn/dt (7) of the refractive index of the material of the seventh lens along with the temperature change is negative, so that the lens group can still keep perfect imaging definition in a certain temperature range.

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, light rays entering the optical system can be effectively converged, and the aperture of the lens of the optical system is reduced. It should be noted, however, that the positions of the diaphragms disclosed herein are merely examples and not limitations; in alternative embodiments, the stop may be disposed at other positions according to actual needs, for example, the stop may be disposed between the fourth lens and the fifth lens.

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

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

In an exemplary embodiment, the third lens and the fourth lens may be combined into a first cemented lens by cementing the image-side surface of the third lens with the object-side surface of the fourth lens. The first cemented lens effectively reduces the chromatic aberration of the system, and because the discrete lens is easily sensitive due to processing/assembling errors if the discrete lens is positioned at the turning position of the light, the first cemented lens effectively reduces the sensitivity.

In an exemplary embodiment, the fifth lens and the sixth lens may be combined into a second cemented lens by cementing the image-side surface of the fifth lens with the object-side surface of the sixth lens. In the second cemented lens, the fifth lens close to the object side has negative focal power, the sixth lens close to the image side has positive focal power, the negative film is arranged in front, and the positive film is arranged at the back, so that the front light can be dispersed, rapidly converged and then transited to the back, the optical path of the back light can be reduced, and the short TTL can be realized. The second cemented lens can effectively reduce the chromatic aberration of the system, make the whole structure of the optical system compact, meet the miniaturization requirement, and simultaneously reduce the tolerance sensitivity problems of inclination/decentration and the like generated in the assembling process of the lens unit.

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

In an exemplary embodiment, the optical back focus BFL of the optical lens and the lens group length TL of the optical lens may satisfy: the BFL/TL ratio is more than or equal to 0.2, and more ideally, the BFL/TL ratio is more than or equal to 0.25. By satisfying the conditional expression BFL/TL is more than or equal to 0.2, the characteristic of the back focal length can be satisfied on the basis of realizing miniaturization, and the assembly of the optical lens is facilitated.

In an exemplary embodiment, the focal length values F1 of the first lens and the entire group of focal length values F of the optical lens may satisfy: F/F1 is not less than 0.15, and more preferably F/F1 is not less than 0.2. The long-focus characteristic of the optical lens can be realized by satisfying the condition that F/F1 is more than or equal to 0.15.

In an exemplary embodiment, the entrance pupil diameter ENPD of the optical lens may satisfy ENPD ≧ 9.0 to achieve a large aperture characteristic.

In an exemplary embodiment, a chief ray angle CRA of the optical lens may satisfy CRA ≦ 5.5 ° to avoid stray light on the lens barrel when the rear end of the ray exits.

In an exemplary embodiment, the lens used in the optical lens may be an aspherical lens or a spherical 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. Under the condition that the important attention is paid to the resolution quality of the lens, the first lens, the second lens, the third lens and the fourth lens can adopt aspheric lenses.

In an exemplary embodiment, the lens used in the optical lens may be a plastic lens, or may be a glass lens. The lens made of plastic has a large thermal expansion coefficient, and when the ambient temperature change of the lens is large, the lens made of plastic causes a large amount of change of the optical back focus of the lens. The glass lens can reduce the influence of temperature on the optical back focus of the lens, but has higher cost. Under the condition that the temperature performance of the lens is focused on, the first lens, the second lens, the third lens and the fourth lens can be made of glass lenses so as to ensure the stability of the optical performance of the lens at different temperatures.

According to the optical lens of the embodiment of the application, through reasonable lens shape setting and focal power setting, the total length of the system is ensured to be short while a long focal length is realized; the optical lens has a smaller CRA, can avoid stray light generated when the rear end of light rays is emitted to a lens barrel, can well match a chip, and cannot generate color cast and dark angle phenomena; the optical lens has a large aperture, has a good imaging effect, can achieve high-definition image quality, and can ensure the definition of an image even in a low-light environment or at night; the optical lens can ensure that the perfect imaging definition is still kept in a certain temperature range. Therefore, the optical lens according to the above-described embodiment of the present application can have at least one of the advantages of miniaturization, small CRA, large aperture, back focal length, low cost, good temperature performance, long-distance imaging, and the like, and can better meet the requirements of the optical lens for vehicle-mounted applications, for example.

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

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

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

Example 1

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

As shown in fig. 1, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

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

The second lens L2 is a meniscus lens with negative power, with the object side S3 being convex and the image side S4 being concave.

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 first 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 sixth lens L6 is a biconvex lens with positive optical power, and has both the object-side surface S10 and the image-side surface S11 convex. Wherein the fifth lens L5 and the sixth lens L6 are cemented with each other to form a second cemented lens.

The seventh lens L7 is a meniscus lens with positive power, with the object side S12 being convex and the image side S13 being concave.

Optionally, the optical lens may further include a filter L8 having an object-side surface S14 and an image-side surface S15, and a protective lens L9 having an object-side surface S16 and an image-side surface S17. Filter L8 can be used to correct for color deviations. The protective lens L9 can be used to protect the image sensing chip on the imaging plane S18. Light from the object passes through each of the surfaces S1 to S17 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	15.5000	4.0000	1.77	49.59
2	25.0953	0.2500
					3	14.0000	2.3000	1.52	64.21
4	6.3461	6.0000
					STO	All-round	1.5000
6	-8.0000	0.7000	1.81	33.28
					7	11.0000	6.0000	1.77	49.59
8	-11.0000	0.2000
					9	34.0699	1.9000	1.85	23.79
10	11.0000	6.5000	1.77	49.59
					11	-23.3889	0.2000
12	13.5888	5.0000	1.50	81.55
					13	50.0000	0.5000
14	All-round	0.5500	1.52	64.21
					15	All-round	8.5000
16	All-round	0.4000
					17	All-round	0.6111
IMA	All-round	/

The present embodiment adopts seven lenses as an example, and by reasonably allocating the focal power and the surface type of each lens, the center thickness of each lens and the air space between each lens, the lens can have at least one of the advantages of miniaturization, small CRA, large aperture, long back focal length, low cost, good temperature performance, long-distance imaging and the like.

Table 2 below gives the entire group focal length value F of the optical lens of embodiment 1, the focal length value F1 of the first lens L1, the total optical length TTL of the optical lens (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface IMA), the lens group length TL of the optical lens (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the center of the image-side surface S13 of the last lens, the seventh lens L7), the optical back focus BFL of the optical lens (i.e., the on-axis distance from the center of the image-side surface S13 of the last lens, the seventh lens L7 to the imaging surface IMA), the entrance pupil diameter ENPD of the optical lens, and the chief ray angle CRA of the optical lens.

TABLE 2

F(mm)	11.9085	BFL(mm)	10.5611
				F1(mm)	45.2890	ENPD(mm)	9.9238
TTL(mm)	45.1111	CRA(°)	3.4
				TL(mm)	34.5500

In the present embodiment, TTL/F is 3.7881 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; the distance between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens is 0.3057; F/F1 is 0.2629 between the focal length F of the whole group of the optical lens and the focal length F1 of the first lens L1; and the change dn/dt (7) — 1.9100E-05 in the refractive index of the material of the seventh lens L7 with temperature change.

Example 2

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

As shown in fig. 2, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

The third lens L3 is a biconcave lens with negative optical power, and both the object-side surface S5 and the image-side surface S6 are concave. The fourth lens L4 is a biconvex lens with positive optical power, and has both the object-side surface S6 and the image-side surface S7 convex. Wherein the third lens L3 and the fourth lens L4 are cemented with each other to form a first cemented lens.

In the optical lens of the present embodiment, a stop STO may be provided between the fourth lens L4 and the fifth lens L5 (i.e., between the first cemented lens and the second cemented lens) to improve the imaging quality.

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 shows the entire group focal length value F of the optical lens, the focal length value F1 of the first lens L1, the total optical length TTL of the optical lens, the lens group length TL of the optical lens, the optical back focus BFL of the optical lens, the entrance pupil diameter ENPD of the optical lens, and the chief ray angle CRA of the optical lens of example 2.

TABLE 3

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	15.0000	4.0000	1.77	49.59
2	25.1082	0.2500
					3	14.4523	2.3000	1.52	64.21
4	6.4069	6.5000
					5	-7.5000	0.7000	1.81	33.28
6	10.5000	6.0000	1.77	49.59
					7	-10.5000	-1.0000
STO	All-round	1.2000
					9	35.0000	1.9000	1.85	23.79
10	12.0000	6.5000	1.77	49.59
					11	-25.0000	0.2000
12	12.7401	5.0000	1.50	81.55
					13	50.0000	0.5000
14	All-round	0.5500	1.52	64.21
					15	All-round	8.5000
16	All-round	0.4000
					17	All-round	0.6625
IMA	All-round	/

TABLE 4

F(mm)	11.9654	BFL(mm)	10.6125
				F1(mm)	41.9501	ENPD(mm)	9.9711
TTL(mm)	44.1625	CRA(°)	3.8
				TL(mm)	33.5500

In the present embodiment, TTL/F is 3.6909 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; the distance between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens is 0.3163; F/F1 is 0.2852 between the focal length F of the whole group of the optical lens and the focal length F1 of the first lens L1; and the change dn/dt (7) — 1.9100E-05 in the refractive index of the material of the seventh lens L7 with temperature change.

Example 3

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

As shown in fig. 3, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

The seventh lens L7 is a biconvex lens with positive optical power, and has concave object-side surface S12 and concave image-side surface S13.

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 3, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 6 below shows the entire group focal length value F of the optical lens, the focal length value F1 of the first lens L1, the total optical length TTL of the optical lens, the lens group length TL of the optical lens, the optical back focus BFL of the optical lens, the entrance pupil diameter ENPD of the optical lens, and the chief ray angle CRA of the optical lens of example 3.

TABLE 5

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	14.0000	4.0000	1.77	49.59
2	24.8769	0.2500
					3	12.0000	2.3000	1.52	64.21
4	5.5925	6.0000
					STO	All-round	1.5000
6	-7.1100	0.7000	1.81	33.28
					7	10.5000	6.0000	1.77	49.59
8	-10.5000	0.2000
					9	36.7397	1.9000	1.85	23.79
10	9.0000	6.5000	1.77	49.59
					11	-25.7265	0.2000
12	14.1217	5.0000	1.50	81.55
					13	-100.0000	0.5000
14	All-round	0.5500	1.52	64.21
					15	All-round	8.5000
16	All-round	0.4000
					17	All-round	0.8565
IMA	All-round	/

TABLE 6

F(mm)	11.8324	BFL(mm)	10.8065
				F1(mm)	36.4265	ENPD(mm)	9.8603
TTL(mm)	45.3565	CRA(°)	2.2
				TL(mm)	34.5500

In the present embodiment, TTL/F is 3.8332 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; the distance between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens is 0.3128; F/F1 is 0.3248 between the focal length F of the whole group of the optical lens and the focal length F1 of the first lens L1; and the change dn/dt (7) — 1.9100E-05 in the refractive index of the material of the seventh lens L7 with temperature change.

Example 4

An optical lens according to embodiment 4 of the present application is described below with reference to fig. 4. 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. 4 shows a schematic structural diagram of an optical lens according to embodiment 4 of the present application.

As shown in fig. 4, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7.

Table 7 below shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 4, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 8 below shows the entire group focal length value F of the optical lens, the focal length value F1 of the first lens L1, the total optical length TTL of the optical lens, the lens group length TL of the optical lens, the optical back focus BFL of the optical lens, the entrance pupil diameter ENPD of the optical lens, and the chief ray angle CRA of the optical lens of example 4.

TABLE 7

TABLE 8

F(mm)	11.9135	BFL(mm)	10.5180
				F1(mm)	36.5931	ENPD(mm)	9.9280
TTL(mm)	43.5680	CRA(°)	3.5
				TL(mm)	33.0500

In the present embodiment, TTL/F is 3.6570 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; the distance between the optical back focus BFL of the optical lens and the lens group length TL of the optical lens is 0.3182; F/F1 of 0.3256 is satisfied between the focal length value F of the whole group of the optical lens and the focal length value F1 of the first lens L1; and the change dn/dt (7) — 1.9100E-05 in the refractive index of the material of the seventh lens L7 with temperature change.

In summary, examples 1 to 4 each satisfy the relationship shown in table 9 below.

TABLE 9

Conditions/examples	1	2	3	4
					TTL/F	3.7881	3.6909	3.8332	3.6570
BFL/TL	0.3057	0.3163	0.3128	0.3182
					F/F1	0.2629	0.2852	0.3248	0.3256
dn/dt(7)	-1.9100E-05	-1.9100E-05	-1.9100E-05	-1.9100E-05

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. 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, a sixth lens, and a seventh lens,

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

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

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

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, and both the object side surface and the image side surface of the fourth lens are convex surfaces;

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

the seventh lens has positive optical power;

the number of lenses with focal power in the optical lens is seven; and

the optical back focus BFL of the optical lens and the lens group length TL of the optical lens meet the following conditions: BFL/TL is more than or equal to 0.2 and less than or equal to 0.3182.

2. An optical lens barrel according to claim 1, wherein the seventh 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 seventh lens element are convex.

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

5. An optical lens according to claim 1, wherein the fifth lens and the sixth lens are cemented to each other to form a second cemented lens.

6. An optical lens according to claim 1, wherein the first lens to the seventh lens are all glass lenses.

7. 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.

8. An optical lens according to any one of claims 1 to 6, characterized in that the total set of focal length values F of the optical lens and the focal length value F1 of the first lens satisfy: F/F1 is not less than 0.15.

9. An optical lens according to any one of claims 1 to 6, characterized in that the change dn/dt of the refractive index of the material of the seventh lens with temperature change is negative.

10. 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, a sixth lens, and a seventh lens,

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

the first lens, the fourth lens, the sixth lens, and the seventh lens each have a positive optical power;

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

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

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

the object side surface of the third lens is a concave surface;

the number of lenses with focal power in the optical lens is seven;

the optical back focus BFL of the optical lens and the lens group length TL of the optical lens meet the following conditions: BFL/TL is more than or equal to 0.2 and less than or equal to 0.3182; 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.

11. An optical lens barrel according to claim 10, wherein the first lens element has a convex object-side surface and a concave image-side surface.

12. An optical lens barrel according to claim 10, wherein the second lens element has a convex object-side surface and a concave image-side surface.

13. An optical lens barrel according to claim 10, wherein the image side surface of the third lens is concave.

14. An optical lens barrel according to claim 10, wherein the object-side surface and the image-side surface of the fourth lens are convex.

15. An optical lens barrel according to claim 10, wherein the fifth lens element has a convex object-side surface and a concave image-side surface.

16. An optical lens barrel according to claim 10, wherein the object-side surface and the image-side surface of the sixth lens element are convex.

17. An optical lens barrel according to claim 10, wherein the seventh lens element has a convex object-side surface and a concave image-side surface.

18. An optical lens barrel according to claim 10, wherein the object side surface and the image side surface of the seventh lens element are convex.

19. An optical lens barrel according to any one of claims 10 to 18, wherein the first lens to the seventh lens are all glass lenses.

20. An optical lens according to any one of claims 10 to 18, characterized in that the total set of focal length values F of the optical lens and the focal length value F1 of the first lens satisfy: F/F1 is not less than 0.15.

21. An optical lens barrel according to any one of claims 10 to 18, wherein the change dn/dt in refractive index of the material of the seventh lens with temperature change is negative.

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