CN111239962A

CN111239962A - Optical lens and imaging apparatus

Info

Publication number: CN111239962A
Application number: CN201811440381.XA
Authority: CN
Inventors: 周宝; 马奥林; 王东方
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2018-11-29
Filing date: 2018-11-29
Publication date: 2020-06-05
Anticipated expiration: 2038-11-29
Also published as: CN111239962B

Abstract

Disclosed are an optical lens and an imaging apparatus. The optical lens sequentially comprises from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first lens has negative focal power, the object side surface of the first lens is a concave surface, and the image side surface of the first lens is a convex 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, the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; the fourth lens has positive focal power, 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 both the object side surface and the image side surface of the fifth lens are convex surfaces; the sixth lens has negative focal power, and both the object side surface and the image side surface of the sixth lens are concave surfaces; and the seventh lens has negative focal power, and the object side surface of the seventh lens is a convex surface and the image side surface of the seventh lens is a concave surface. According to the optical lens, at least one of the advantages of high resolution, small distortion, large aperture, miniaturization, small front end caliber, low cost and the like can be achieved.

Description

Optical lens and imaging apparatus

Technical Field

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

Background

With the continuous improvement of the level of the automatic driving technology, the optical lens plays a crucial role in the aspect of visual sensing of the automobile, and the performance of the optical lens directly influences the safety in the automatic driving process.

At present, the optical lens for vehicle applications is developing towards the trend of large chip and high pixel. First, the increase in the size of the lens chip increases the overall lens length to some extent, thereby affecting the miniaturization of the lens. Secondly, in order to improve the resolution capability of the vehicle-mounted application lens, more lenses are generally selected, so that the miniaturization of the lens is seriously influenced while high resolution is pursued. In addition, such optical lenses require a larger aperture to enable use in low light environments; smaller CRA's are needed to match ten million pixel chips without color cast; less distortion is required to ensure that the picture is not distorted.

Therefore, there is a need in the market for an optical lens with high resolution, small size, large aperture, small distortion, low cost, and the like, which can be used in low light environment to meet the requirements of automatic driving applications.

Disclosure of Invention

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

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

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

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

In one embodiment, the seventh lens may be an aspherical 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 3.5.

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 0.1.

In one embodiment, the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens may satisfy: D/H/FOV is less than or equal to 0.05.

In one embodiment, a center radius of curvature R8 of the object-side surface of the fifth lens and a center radius of curvature R9 of the image-side surface of the fifth lens may satisfy: the absolute value of R8/R9 is more than or equal to 0.6 and less than or equal to 1.4.

In one embodiment, the maximum field angle FOV of the optical lens, the entire set of focal length values F of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens may satisfy: (FOV F)/H is less than or equal to 70.

In one embodiment, a center radius of curvature R2 of the image side surface of the first lens and a center radius of curvature R4 of the object side surface of the second lens may satisfy: (R2-R4)/(R2+ R4) is less than or equal to 4.

In one embodiment, the conditional formula may be satisfied: 0.2 ≦ (SAG11/d11)/(SAG12/d12) ≦ 0.8, wherein d11 is a half aperture of the maximum clear aperture of the seventh lens object-side surface corresponding to the maximum angle of view of the optical lens, SAG11 is a rise SG value of the seventh lens object-side surface corresponding to the maximum angle of view of the optical lens, d12 is a half aperture of the maximum clear aperture of the seventh lens image-side surface corresponding to the maximum angle of view of the optical lens, and SAG12 is a rise SG value of the seventh lens image-side surface corresponding to the maximum angle of view of the optical lens.

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 third lens, the sixth lens and the seventh lens all have negative focal power; the second lens, the fourth lens and the fifth lens can all have positive focal power; the second lens and the third lens can be mutually glued to form a first cemented lens; the fourth lens, the fifth lens and the sixth lens can be cemented to form a second cemented lens; and the total optical length TTL of the optical lens and the whole group of focal length values F of the optical lens can meet the following requirements: TTL/F is less than or equal to 3.5.

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

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

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

In one embodiment, the object-side surface of the fourth 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 fifth lens can be convex.

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

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

In one embodiment, the seventh lens may be an aspherical lens.

In one embodiment, the conditional formula may be satisfied: 0.2 ≦ (SAG11/d11)/(SAG12/d12) ≦ 0.8, wherein d11 is a half aperture of the maximum clear aperture of the object-side surface of the seventh lens corresponding to the maximum angle of view of the optical lens, SAG11 is a rise SG value of the object-side surface of the seventh lens corresponding to the maximum angle of view of the optical lens, d12 is a half aperture of the maximum clear aperture of the image-side surface of the seventh lens corresponding to the maximum angle of view of the optical lens, and SAG12 is a rise SG value of the image-side surface of the seventh lens corresponding to the maximum angle of view of the optical lens.

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 lens, so that at least one of the beneficial effects of high resolution, small distortion, large aperture, miniaturization, small front end aperture, low cost and the like of the optical lens is realized.

Drawings

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

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

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

fig. 3 schematically shows the half caliber d/d 'of the maximum clear caliber of the object/image side of the lens and the corresponding rise Sg value SAG/SAG'.

Detailed Description

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

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

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

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

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

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

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

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

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

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

The first lens element can have a negative power, and can have a concave object-side surface and a convex image-side surface. The first lens element is convex toward the image side and has a meniscus shape with a convex radius of a large absolute value (1< R2/R1<4), thereby effectively correcting field curvature.

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

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

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

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

The seventh lens element can have a negative power, and can have a convex object-side surface and a concave image-side surface. The seventh lens has negative focal power, can disperse light rays passing through the front optical system, and can obtain larger image height under the condition of certain back focus, thereby achieving the purpose of being matched with a larger chip.

In an exemplary embodiment, a diaphragm for limiting the light beam may be disposed between, for example, the first lens and the second lens to further improve the imaging quality of the lens. When the diaphragm is arranged between the first lens and the second lens, the effective beam-closing of light rays entering the optical system can be facilitated, the aperture of the lens of the optical system is reduced, and the aperture is enlarged. It should be noted, however, that the positions of the diaphragms disclosed herein are merely examples and not limitations; in alternative embodiments, the diaphragm may be disposed at other positions according to actual needs.

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

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

In an exemplary embodiment, the second lens and the third lens may be combined into the first cemented lens by cementing the image-side surface of the second lens with the object-side surface of the third lens. The first cemented lens is composed of a positive lens (namely, a second lens) and a negative lens (namely, a third lens), the combination of the positive lens and the negative lens can perform self achromatization, reduce tolerance sensitivity, also can remain partial chromatic aberration to balance chromatic aberration of a system, enables the whole structure of the optical system to be compact, meets the miniaturization requirement, and simultaneously reduces tolerance sensitivity problems of inclination/decentration and the like of the lens unit caused in the assembling process.

In an exemplary embodiment, the fourth lens, the fifth lens and the sixth lens can be combined into a second cemented lens by cementing the image side surface of the fourth lens with the object side surface of the fifth lens and cementing the image side surface of the fifth lens with the object side surface of the sixth lens, the second cemented lens is a triple cemented lens, and at least one of the following beneficial effects can be achieved by adopting the triple cemented lens, wherein ① reduces the air space between the three lenses and reduces the total length of the whole optical system, ② reduces the assembly components between the three lenses and reduces the procedures, the assembly is convenient, the cost is reduced, ③ reduces tolerance sensitivity problems of lens units caused by inclination/decentration in the assembly process, ④ reduces the light quantity loss caused by reflection between the lenses and improves the relative illumination of the system, and the combination of ⑤ positive and negative lenses can further reduce the curvature of field and can correct the off-axis point aberration of the system.

In the second cemented lens, the fourth lens and the fifth lens have positive focal power, which can further correct the aberration generated by the front lens group and make the light beam converge quickly so as to shorten the total length of the lens and make the optical system more compact; the sixth lens has negative focal power, and can disperse the light rays passing through the fifth lens so as to enable the light rays to be smoothly transited to the next lens. Meanwhile, the combination of the positive lens and the negative lens can better correct the aberration of the optical system, and on the premise of compact structure, the resolution can be improved, and the optical performances such as distortion, CRA and the like can be optimized.

The use of the first cemented lens and the second cemented lens shares the whole chromatic aberration correction of the system, can effectively correct aberration to improve the resolution, and enables the optical system to be compact as a whole to meet the miniaturization requirement.

In an exemplary embodiment, an optical total length TTL of the optical lens and a whole set of focal length values F of the optical lens may satisfy: TTL/F is less than or equal to 3.5, and more ideally, TTL/F is less than or equal to 3. The condition TTL/F is less than or equal to 3.5, 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 0.1, and more ideally, the BFL/TL ratio is more than or equal to 0.15. By satisfying the conditional expression BFL/TL is more than or equal to 0.1, 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 maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens may satisfy: D/H/FOV is 0.05 or less, and more preferably, D/H/FOV is 0.04 or less. The requirement of the conditional expression D/H/FOV is less than or equal to 0.05, and the small caliber at the front end can be ensured.

In an exemplary embodiment, a center radius of curvature R8 of the object-side surface of the fifth lens and a center radius of curvature R9 of the image-side surface of the fifth lens may satisfy: the absolute value of R8/R9 is more than or equal to 0.6 and less than or equal to 1.4, and more ideally, the absolute value of R8/R9 is more than or equal to 0.8 and less than or equal to 1.2. By controlling the curvature radius of the two convex surfaces of the fifth lens to be close, the correction of the aberration can be facilitated.

In an exemplary embodiment, the maximum field angle FOV of the optical lens, the entire set of focal length values F of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens may satisfy: (FOV F)/H.ltoreq.70, and more desirably, (FOV F)/H.ltoreq.60 can be further satisfied. Satisfies the conditional expression (FOV multiplied by F)/H is less than or equal to 70, and can ensure the small distortion characteristic.

In an exemplary embodiment, a center radius of curvature R2 of the image side surface of the first lens and a center radius of curvature R4 of the object side surface of the second lens may satisfy: (R2-R4)/(R2+ R4). ltoreq.4, and more preferably (R2-R4)/(R2+ R4). ltoreq.3. Satisfying the conditional expression (R2-R4)/(R2+ R4) ≦ 4, corrects aberration of the optical system, and ensures that an incident angle is not too large when the light exiting from the first lens is incident on the first face of the second lens, thereby reducing tolerance sensitivity of the optical system.

In an exemplary embodiment, the half aperture d11 of the maximum clear aperture of the seventh lens object-side surface corresponding to the maximum field angle of the optical lens and the corresponding rise SG value SAG11, and the half aperture d12 of the maximum clear aperture of the seventh lens image-side surface corresponding to the maximum field angle of the optical lens and the corresponding rise SG value SAG12 may satisfy: 0.2. ltoreq. SAG11/d11)/(SAG12/d 12. ltoreq.0.8, and desirably, 0.3. ltoreq. SAG11/d11)/(SAG12/d 12. ltoreq.0.6. The shapes of the two surfaces of the seventh lens are close through arrangement, so that the peripheral light can be smoothly transited, and the sensitivity of the lens is reduced.

In an exemplary embodiment, the seventh lens of the optical lens according to the present application may employ an aspherical mirror. The aspheric lens has the characteristics that: the curvature varies continuously from the center of the lens to the periphery. Unlike a spherical lens having a constant curvature from the center to the periphery of the lens, an aspherical lens has better curvature radius characteristics, and has the advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated in imaging can be eliminated as much as possible, so that the imaging quality of the lens is improved. The seventh lens adopts an aspheric lens, so that various aberrations of the optical system can be fully corrected, and the resolution of the optical system is improved on the premise of compact structure. It should be understood that, in order to improve the imaging quality, the optical lens according to the present application may increase the number of the aspheric lenses, for example, when the resolution quality of the optical lens is focused, the aspheric lenses may be used for the first lens to the seventh lens.

In an exemplary embodiment, the 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.

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

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

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

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

Example 1

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

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

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

The second lens L2 is a biconvex lens with positive optical power, and has both the object-side surface S4 and the image-side surface S5 being convex. The third lens L3 is a meniscus lens with negative power, with the object side S5 being concave and the image side S6 being convex. The second lens L2 and the third lens L3 are cemented with each other to form a first cemented lens.

The fourth lens L4 is a meniscus lens with positive power, with the object side S7 being convex and the image side S8 being concave. The fifth lens L5 is a biconvex lens with positive optical power, and has both the object-side surface S8 and the image-side surface S9 convex. The sixth lens L6 is a biconcave lens with negative optical power, and has concave object-side surface S9 and concave image-side surface S10. Wherein the fourth lens L4, the fifth lens L5, and the sixth lens L6 are cemented to form a second cemented lens.

The seventh lens L7 is a meniscus lens with negative power, with the object side S11 being convex and the image side S12 being concave. The seventh lens element L7 is an aspherical lens, and both the object-side surface S11 and the image-side surface S12 are aspherical.

Optionally, the optical lens may further include a filter L8 and/or a protective lens L8' having an object side S13 and an image side S14. Filter L8 can be used to correct for color deviations. The protective lens L8' may be used to protect the image sensing chip on the imaging plane IMA. Light from the object passes through each of the surfaces S1 to S14 in sequence and is finally imaged on the imaging plane IMA.

In the optical lens of the present embodiment, a stop STO may be provided between the first lens L1 and the second lens L2 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	-16.1000	4.8569	1.75	35.02
2	-41.6640	0.9790
					STO	All-round	0.6234
4	20.0000	6.1500	1.50	66.05
					5	-16.9000	2.3000	1.72	50.35
6	-30.4862	0.3500
					7	15.2768	3.0078	1.88	40.81
8	24.0000	6.0392	1.64	34.49
					9	-24.0000	3.1137	1.74	28.29
10	24.0956	2.6604
					11	13.3000	3.2783	1.79	44.21
12	9.2000	2.3405
					13	All-round	0.5500	1.52	64.21
14	All-round	4.7588
					IMA	All-round	/

The present embodiment adopts seven lenses as an example, and by reasonably distributing the focal power and the surface type of each lens, the center thickness of each lens and the air space between each lens, the lens has the beneficial effects of high resolution, small distortion, large aperture, miniaturization, small front end aperture, low cost and the like. Each aspherical surface type Z is defined by the following formula:

wherein Z is the distance rise from the vertex of the aspheric surface when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is 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 the conic coefficients k and the high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S11 and S12 in example 1.

TABLE 2

Flour mark

K

A

B

C

D

E

11

-2.8974

-4.6313E-04

-8.8355E-06

2.0078E-07

-1.1642E-08

2.6555E-10

12

-1.5055

-3.9101E-04

-9.4211E-06

2.8811E-07

-8.1543E-09

2.1006E-10

Table 3 below gives the total optical length TTL of the optical lens of example 1 (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface IMA), the entire group focal length value F of the optical lens, the optical back focus BFL of the optical lens (i.e., the on-axis distance from the center of the image-side surface S12 of the last lens L7 to the imaging surface IMA), the lens group length TL of the optical lens (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the center of the image-side surface S12 of the last lens L7), the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens, the image height H corresponding to the maximum field angle of the optical lens, the maximum field angle FOV of the optical lens, the center curvature radius R59648 of the object-side surface S1 and the side surface S3985 of the first lens L1, the center curvature radius R1-R5848 of the object-side surface S2 of the second lens L2, the maximum field, The central curvature radii R8-R9 of the object-side surface S8 and the image-side surface S9 of the fifth lens L5, the half aperture d11 of the maximum clear aperture of the object-side surface S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and the corresponding rise SG value SAG11 (see fig. 3), and the half aperture d12 of the maximum clear aperture of the image-side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and the corresponding rise SG value SAG12 (see fig. 3).

TABLE 3

TTL(mm)	41.0080	R4(mm)	20.0000
				F(mm)	20.3227	R8(mm)	24.0000
BFL(mm)	7.6493	R9(mm)	-24.0000
				TL(mm)	33.3587	SAG11(mm)	0.4818
D(mm)	11.8994	SAG12(mm)	0.9892
				H(mm)	11.0100	d11(mm)	5.1909
FOV(°)	30	d12(mm)	4.9465
				R1(mm)	-16.1000
R2(mm)	-41.6640

In the present embodiment, TTL/F is 2.0178 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 0.2293; the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens satisfy D/H/FOV of 0.0360; the maximum view field angle FOV of the optical lens, the whole group of focal length values F of the optical lens and the image height H corresponding to the maximum view field angle of the optical lens satisfy (FOV multiplied by F)/H which is 55.3752; a central curvature radius R2 of the image-side surface S2 of the first lens L1 and a central curvature radius R4 of the object-side surface S4 of the second lens L2 satisfy (R2-R4)/(R2+ R4) ═ 2.8464; the central curvature radius R8 of the object-side surface S8 of the fifth lens L5 and the central curvature radius R9 of the image-side surface S9 of the fifth lens L5 satisfy | R8/R9| ═ 1.0000; a half aperture d11 of the maximum clear aperture of the object side surface S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG11 corresponding thereto satisfy (SAG11/d11)/(SAG12/d12) 0.4641 between a half aperture d12 of the maximum clear aperture of the image side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG12 corresponding thereto; and the central curvature radius R1 of the object-side surface S1 of the first lens L1 and the central curvature radius R2 of the image-side surface S2 of the first lens L1 satisfy | R2/R1| ═ 2.5878.

Example 2

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

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

Table 4 below shows a radius of curvature R, a thickness T, a refractive index Nd, and an abbe number Vd of each lens of the optical lens of example 2, where the radius of curvature R and the thickness T are both in units of millimeters (mm). Table 5 below shows the conic coefficients k and the high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S11 and S12 in example 2. Table 6 below shows the total optical length TTL of the optical lens, the entire group focal length F of the optical lens, the optical back focus BFL of the optical lens, the lens group length TL of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens, the image height H corresponding to the maximum field angle of the optical lens, the maximum field angle FOV of the optical lens, the central curvature radii R1-R2 of the object-side surface S1 and the image-side surface S2 of the first lens L1, the central curvature radius R4 of the object-side surface S4 of the second lens L2, the central curvature radii R8-R9 of the object-side surface S8 and the image-side surface S9 of the fifth lens L5, the half-aperture D11 of the maximum clear aperture S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens, the corresponding to the maximum field angle of the fifth lens L5, the corresponding to the half-aperture D11 and the corresponding to the maximum field angle SG 48 of the seventh lens L12, and the corresponding to the maximum field angle of the seventh lens L573 High SG value SAG 12.

TABLE 4

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	-15.6000	5.3306	1.73	54.67
2	-50.5031	0.8062
					STO	All-round	0.6090
4	20.7252	4.6606	1.62	63.88
					5	-20.7252	2.6612	1.70	41.14
6	-49.9928	0.1000
					7	16.1824	3.1709	1.88	37.21
8	25.5000	4.5062	1.59	68.53
					9	-25.5000	5.5787	1.76	26.56
10	37.7529	1.9091
					11	16.6805	4.1603	1.76	26.56
12	10.6837	2.7834
					13	All-round	0.5500	1.52	64.21
14	All-round	4.1744
					IMA	All-round	/

TABLE 5

Flour mark

K

A

B

C

D

E

11

0.0616

-5.2694E-04

-8.1090E-06

9.0871E-08

-3.0530E-09

8.4147E-11

12

0.6215

-6.4757E-04

-6.7537E-06

1.3388E-07

-5.3629E-09

1.4764E-10

TABLE 6

In the present embodiment, TTL/F is 2.0440 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 0.2242; the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface S1 of the first lens L1 corresponding to the maximum field angle of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens satisfy a D/H/FOV of 0.0367; the maximum view field angle FOV of the optical lens, the whole group of focal length values F of the optical lens and the image height H corresponding to the maximum view field angle of the optical lens satisfy (FOV multiplied by F)/H which is 56.3236; a central curvature radius R2 of the image-side surface S2 of the first lens L1 and a central curvature radius R4 of the object-side surface S4 of the second lens L2 satisfy (R2-R4)/(R2+ R4) ═ 2.3920; the central curvature radius R8 of the object-side surface S8 of the fifth lens L5 and the central curvature radius R9 of the image-side surface S9 of the fifth lens L5 satisfy | R8/R9| ═ 1.0000; a half aperture d11 of the maximum clear aperture of the object side surface S11 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG11 corresponding thereto satisfy (SAG11/d11)/(SAG12/d12) 0.3886 between a half aperture d12 of the maximum clear aperture of the image side surface S12 of the seventh lens L7 corresponding to the maximum field angle of the optical lens and a rise SG value SAG12 corresponding thereto; and the central curvature radius R1 of the object-side surface S1 of the first lens L1 and the central curvature radius R2 of the image-side surface S2 of the first lens L1 satisfy | R2/R1| ═ 3.2374.

In summary, example 1 and example 2 each satisfy the relationship shown in table 7 below.

TABLE 7

Conditions/examples	1	2
			TTL/F	2.0178	2.0440
BFL/TL	0.2293	0.2242
			D/H/FOV	0.0360	0.0367
FOV*F/H	55.3752	56.3236
			(R2-R4)/(R2+R4)	2.8464	2.3920
\|R8/R9\|	1.0000	1.0000
			(SAG11/d11)/(SAG12/d12)	0.4641	0.3886
R2/R1	2.5878	3.2374

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

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

the sixth lens has negative focal power, and both the object side surface and the image side surface of the sixth lens are concave; and

the seventh lens element has a negative focal power, and has a convex object-side surface and a concave image-side surface.

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

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

4. An optical lens according to claim 1, characterized in that the seventh lens is an aspherical mirror.

5. An optical lens according to any one of claims 1 to 4, 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 3.5.

6. An optical lens according to any of claims 1-4, characterized in that between an optical back focus BFL of the optical lens and a lens group length TL of the optical lens satisfies: BFL/TL is more than or equal to 0.1.

7. An optical lens according to any one of claims 1 to 4, wherein the maximum field angle FOV of the optical lens, the maximum clear aperture D of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens satisfy: D/H/FOV is less than or equal to 0.05.

8. An optical lens barrel according to any one of claims 1 to 4, wherein a central radius of curvature R8 of an object side surface of the fifth lens and a central radius of curvature R9 of an image side surface of the fifth lens satisfy: the absolute value of R8/R9 is more than or equal to 0.6 and less than or equal to 1.4.

9. The optical lens according to any one of claims 1 to 4, wherein the maximum field angle FOV of the optical lens, the entire group of focal length values F of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens satisfy: (FOV F)/H is less than or equal to 70.

10. An optical lens barrel according to any one of claims 1 to 4, wherein the central radius of curvature R2 of the image side surface of the first lens and the central radius of curvature R4 of the object side surface of the second lens satisfy: (R2-R4)/(R2+ R4) is less than or equal to 4.

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

0.2≤(SAG11/d11)/(SAG12/d12)≤0.8，

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

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

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

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

12. 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 third lens, the sixth lens, and the seventh lens each have a negative optical power;

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

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

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

the total optical length TTL of the optical lens and the whole group of focal length values F of the optical lens meet the following conditions: TTL/F is less than or equal to 3.5.

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