CN111474673B

CN111474673B - Optical lens and imaging apparatus

Info

Publication number: CN111474673B
Application number: CN201910068111.9A
Authority: CN
Inventors: 李响; 王东方
Original assignee: Ningbo Sunny Automotive Optech Co Ltd
Current assignee: Ningbo Sunny Automotive Optech Co Ltd
Priority date: 2019-01-24
Filing date: 2019-01-24
Publication date: 2021-09-17
Anticipated expiration: 2039-01-24
Also published as: CN111474673A

Abstract

An optical lens and an imaging apparatus including the same are disclosed. The optical lens sequentially comprises from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, 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 convex surface, and the image side surface of the first lens is a concave surface; the second lens has negative focal power, and the object side surface and the image side surface of the second lens are both concave surfaces; the third lens has positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the fourth lens has positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces; 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 positive focal power, and both the object-side surface and the image-side surface of the seventh lens are convex. The optical lens can achieve at least one of the advantages of high resolution, low lens sensitivity, small front end aperture, small CRA (cross-cut interference) and large aperture.

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 development of science and technology and the improvement of living standard of people, automobiles become the most common transportation means.

With the popularization of unmanned technology, the pixel requirements of vehicle-mounted application lenses serving as automobile eyes are higher and higher. At present, the vehicle-mounted application lens with million-level pixels is gradually popularized and is developed towards the trend of higher pixels. In order to achieve high resolution, high resolution is generally obtained by increasing the number of lenses, but this affects miniaturization of the lens. And the high-pixel lens needs a larger aperture to realize the use in a low-light environment; smaller CRAs are needed so that no color cast occurs when the chips are matched.

Therefore, there is an ongoing need in the market for an optical lens that has high resolution, high image quality, small size, low cost, and can be used in low light environments.

Disclosure of Invention

The application aims to develop a high-pixel optical system for a vehicle, which is used for automatic driving so as to ensure the safety of drivers and passers-by and reduce the risk of accidents; the method aims to solve the problem of temperature stability of the lens, so that the lens still has perfect image resolving capability under different temperature conditions; the application aims to solve the problems of high pixel, low cost and miniaturization of the lens.

Accordingly, the present application provides an optical lens that may be adapted for, for example, vehicle-mounted mounting, that may at least overcome, or partially overcome, 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, 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 both the object side surface and the image side surface of the second lens are concave; the third lens can have positive focal power, and the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the fourth lens can have positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces; 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 may have a positive optical power, and both the object-side surface and the image-side surface thereof are convex.

In one embodiment, the second lens, the third lens and the fourth lens may be cemented 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, at least one of the first lens and the seventh lens may be an aspherical mirror.

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 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 0.08.

In one embodiment, the optical back focus BFL of the optical lens and the total optical length TTL of the optical lens may satisfy: BFL/TTL is more than or equal to 0.3.

In one embodiment, an on-axis distance d68 from the image-side surface of the fourth lens to the object-side surface of the fifth lens may satisfy: d68/TTL is less than or equal to 0.025.

In one embodiment, a center radius of curvature R11 of the object-side surface of the seventh lens and a center radius of curvature R12 of the image-side surface of the seventh lens may satisfy: the ratio of (R11+ R12)/(R11-R12) is not more than 0.2 and not more than 0.45.

In one embodiment, the total optical length TTL of the optical lens, the maximum field angle FOV of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens may satisfy: TTL/H/FOV is less than or equal to 0.2.

In one embodiment, a combined focal length value F56 of the fifth lens and the sixth lens and a whole set focal length value F of the optical lens may satisfy: the absolute value of F56/F is more than or equal to 7.8 and less than or equal to 9.

In one embodiment, a center radius of curvature R2 of the image side surface of the first lens and a center radius of curvature R3 of the object side surface of the second lens may satisfy: 2.5-1.5 (R2-R3)/(R2+ R3).

In one embodiment, the focal length value F7 of the seventh lens and the focal length value F of the whole group of the optical lens satisfy: F7/F is less than or equal to 1.7.

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 second lens and the sixth lens can all have negative focal power; the third lens, the fourth lens, the fifth lens and the seventh lens may each have positive optical power; the second lens, the third lens and the fourth lens can be cemented 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, both the object-side surface and the image-side surface of the second lens can be concave.

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

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, both the object-side surface and the image-side surface of the seventh lens element can be convex.

In one embodiment, each of the first to seventh lenses may be a glass 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, low lens sensitivity, high production yield, small front-end caliber, small Chief Ray Angle (CRA), large aperture and the like of the optical lens is realized.

Drawings

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

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

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

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

Detailed Description

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

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

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

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

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

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

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

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

An optical lens according to an exemplary embodiment of the present application includes, for example, 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 convex object-side surface and a concave image-side surface. The first lens is in a meniscus shape with the convex surface facing the object side, so that light rays with a large view field can be collected as far as possible, the light rays enter the rear optical system, the light flux is increased, and the whole large view field range can be realized. In practical application, considering the outdoor installation and use environment of the vehicle-mounted application-like lens, the lens can be in severe weather such as rain, snow and the like, and the first lens is arranged in the meniscus shape with the convex surface facing the object side, so that water drops and the like can slide off favorably, and the influence on the imaging quality of the lens is reduced.

The second lens can have a negative optical power, and both the object-side surface and the image-side surface can be concave. The second lens is a biconcave lens, so that the light rays diffused by the first lens can smoothly enter a rear system; in addition, the arrangement can be beneficial to correcting high-order aberration and is more beneficial to reducing the attenuation degree of the relative illumination of the lens.

The third lens element can have a positive power, and can have a convex object-side surface and a concave image-side surface. The third lens is provided with a positive lens which can quickly converge the front large-angle light to a rear system, so that the optical path of the rear light is favorably reduced, and the short TTL is realized.

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

The fifth lens element can have a positive optical power, and can have a convex object-side surface and a convex image-side surface. The fifth lens is set to have positive focal power, and a fifth lens with positive focal power is used after the aperture stop is set, so that the aberration generated by the front lens group can be further corrected, and meanwhile, the light beams are converged again, so that the aperture of the lens can be enlarged, the total length of the lens can be shortened, the optical system is more compact, and the optical system has relatively shorter total length of the lens.

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 positive optical power, and can have a convex object-side surface and a convex image-side surface. The seventh lens can enable the light passing through the sixth lens to be more gradually transited to an imaging surface, so that the total length of the system is reduced. Meanwhile, various aberrations of the optical system are fully corrected, the resolution can be improved, and the optical performances such as distortion, CRA and the like can be optimized on the premise of compact structure.

In an exemplary embodiment, a stop for limiting the light beam may be disposed between, for example, the fourth lens and the fifth lens to further improve the imaging quality of the lens. When the diaphragm is arranged between the fourth lens and the fifth lens, the aperture of the lens at the front end of the lens can be effectively reduced, and the realization of large aperture can be facilitated. 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, the third lens, and the fourth lens may be combined into the first cemented lens by cementing an image-side surface of the second lens with an object-side surface of the third lens, and cementing an image-side surface of the third lens with an object-side surface of the fourth lens. The first cemented lens is a tri-cemented lens, and the use of the tri-cemented lens can have at least one of the following beneficial effects: the air intervals among the three lenses are reduced, and the total length of the whole optical system is reduced; the assembly parts among the three lenses are reduced, the working procedures are reduced, the assembly is convenient, and the cost is reduced; the tolerance sensitivity problems of inclination/core deviation and the like generated in the assembling process of the lens unit are reduced; fourthly, the light quantity loss caused by reflection among the lenses is reduced, and the relative illumination of the system is improved; the field curvature can be further reduced, and the off-axis point aberration of the system can be corrected.

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. The second cemented lens is composed of a positive lens (i.e., a fifth lens) and a negative lens (i.e., a sixth lens), wherein the positive lens has a lower refractive index, the negative lens has a higher refractive index (compared with the positive lens), and the matching of the high refractive index and the low refractive index can be beneficial to the rapid transition of the front light, so that the aperture of the diaphragm is increased to meet the requirement of night vision. In addition, the positive lens and the negative lens can be glued to achieve self achromatization, reduce field curvature and correct coma aberration, wherein the fifth lens serving as the positive lens is arranged in front, so that light can be further converged, and the total TTL is reduced. The adoption of the gluing piece 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/core deviation and the like generated in the assembling process of the lens unit; if the discrete lens is located at the turning point of the light, the sensitivity is easily caused by processing/assembling errors, so that the sensitivity of the cemented lens group can be effectively reduced.

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 4.5, and more ideally, TTL/F is less than or equal to 4.2. The condition TTL/F is less than or equal to 4.5, and the miniaturization characteristic of the system can be ensured.

In an exemplary embodiment, the 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 0.08 or less, and more preferably, D/H/FOV is 0.05 or less. The requirement of the conditional expression D/H/FOV is less than or equal to 0.08, and the small caliber at the front end can be ensured.

In an exemplary embodiment, the optical back focus BFL of the optical lens and the total optical length TTL of the optical lens may satisfy: the BFL/TTL is more than or equal to 0.3, and more ideally, the BFL/TTL can be further more than or equal to 0.35. By satisfying the condition that BFL/TTL is more than or equal to 0.3, the characteristic of the back focal length can be realized, and the assembly of the optical lens is facilitated.

In an exemplary embodiment, an on-axis distance d68 from the image-side surface of the fourth lens to the object-side surface of the fifth lens may satisfy: d68/TTL is not more than 0.025, more preferably, 0.003 not more than d68/TTL not more than 0.02. By controlling the distance between two groups of adjacent cemented lenses, light rays near the gentle transition diaphragm can be facilitated, and the image quality can be improved.

In an exemplary embodiment, a center radius of curvature R11 of the object-side surface of the seventh lens and a center radius of curvature R12 of the image-side surface of the seventh lens may satisfy: not less than 0.2 (R11+ R12)/(R11-R12) not more than 0.45, more preferably not less than 0.25 (R11+ R12)/(R11-R12) not more than 0.4. The seventh lens is the lens most sensitive to the yield in all the lenses, and the molding processability of the seventh lens can be facilitated by satisfying the conditional expression, so that the production yield is improved.

In an exemplary embodiment, the total optical length TTL of the optical lens, the maximum field angle FOV of the optical lens, and the image height H corresponding to the maximum field angle of the optical lens may satisfy: TTL/H/FOV is less than or equal to 0.2, and more ideally, TTL/H/FOV is less than or equal to 0.1. By satisfying the conditional expression TTL/H/FOV less than or equal to 0.2, the miniaturization characteristic can be ensured.

In an exemplary embodiment, a combined focal length value F56 of the fifth lens and the sixth lens and a full set focal length value F of the optical lens may satisfy: the absolute value of F56/F is more than or equal to 7.8 and less than or equal to 9, and more preferably, the absolute value of F56/F is more than or equal to 8.8. By controlling the direction of the light rays between the fourth lens and the seventh lens, the aberration caused by the large-angle light rays entering through the third lens can be reduced, and meanwhile, the lens is compact in structure and beneficial to miniaturization.

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 R3 of the object side surface of the second lens may satisfy: (R2-R3)/(R2+ R3) is not more than-2.5 and not more than-1.5, and more preferably, it further satisfies (R2-R3)/(R2+ R3) not more than-1.7. By satisfying the conditional expression-2.5 ≦ (R2-R3)/(R2+ R3) ≦ -1.5, aberration of the optical system can be corrected, and it is ensured that when the light emitted from the first lens is incident on the first face (i.e., the object side face) of the second lens, the incident angle is not too large, thereby reducing tolerance sensitivity of the optical system; if the aberration exceeds the upper limit value, the aberration of the optical system cannot be sufficiently corrected; if the light incident angle is less than the lower limit value, the incident angle of the light emitted from the first lens when the light enters the first surface (i.e., the object side surface) of the second lens is too large, and the sensitivity of the optical system is increased.

In an exemplary embodiment, a focal length value F7 of the seventh lens and a focal length value F of the entire group of the optical lens may satisfy: F7/F is not more than 1.7, and more preferably, F7/F is not more than 1.5. The seventh lens is configured to have a short focal length, which can help to collect light and ensure the light flux of the system.

In an exemplary embodiment, at least one of the first lens and the seventh lens of the optical lens according to the present application may employ an aspherical mirror to further improve the resolution quality. 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. 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 adopted for the first lens to the seventh lens.

In an exemplary embodiment, the first lens to the seventh lens of the optical lens according to the present application may each employ a glass mirror. Because the thermal expansion coefficient of the lens made of plastic is large, when the ambient temperature change of the lens is large, the lens made of plastic causes the optical back focus variation of the lens to be large. The glass lens can reduce the influence of temperature on the optical back focus of the lens, but the cost is higher. The optical lens according to the application adopts the glass aspheric lens, and can have temperature stability, so the optical lens is particularly suitable for the application of a front-view lens. It should be understood that this is by way of example only and not by way of limitation, and that plastic lenses may also be used for certain lenses where temperature stability is not a particular requirement to reduce cost.

Therefore, the optical lens according to the above-described embodiment of the present application has at least one of the following advantageous effects: 1) high resolution-on the basis of reasonable lens shape design and material collocation, the resolution is improved by adopting 2 aspheric lenses, so that high resolution is realized; 2) the lens has low sensitivity and high production yield, and the low-cost requirements of low sensitivity and high production yield are realized by controlling the shape and focal power of the lens; 3) the front end small caliber-the whole front port is small, and the caliber is usually large when the conventional framework with similar performance is achieved; 4) the CRA is small, the main ray angle CRA of the lens is small, stray light generated when the rear end of the ray is emitted to a lens barrel can be avoided, the lens can be well matched with a vehicle-mounted chip, and color cast and dark angle phenomena cannot be generated; and 5) the large aperture has a large aperture, so that the imaging effect is good, the image quality can reach the million high-definition level, and the image can be ensured to be clear even in a low-light environment or at night. 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; and the optical back focus BFL of the optical lens means an on-axis distance from the center of the seventh lens image-side surface of the last lens to the center of the image plane.

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 convex and the image side S2 being concave.

The second lens L2 is a biconcave lens with negative optical power, and both the object-side surface S3 and the image-side surface S4 are concave. The third lens L3 is a meniscus lens with positive power, with the object side S4 being convex and the image side S5 being concave. The fourth lens L4 is a biconvex lens with positive optical power, and has both the object-side surface S5 and the image-side surface S6 convex. Wherein the second lens L2, the third lens L3, and the fourth lens L4 are cemented to form a first cemented lens.

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 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 biconvex lens with positive optical power, and has both the object-side surface S11 and the image-side surface S12 convex.

The first lens element L1 and the seventh lens element L7 are both aspheric lenses, and both the object-side surface and the image-side surface thereof are aspheric.

Optionally, the optical lens may further include a filter L8 having an object-side surface S13 and an image-side surface S14, and a protective lens L9 having an object-side surface S15 and an image-side surface S16. Filter L8 can be used to correct for color deviations. The protective lens L9 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 S16 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 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 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

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 can have at least one of the advantages of high resolution, low lens sensitivity, high production yield, small front end caliber, small CRA, large aperture and the like. Each aspherical surface type Z is defined by the following formula:

wherein Z is the distance rise from the vertex of the aspheric surface when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is the conic coefficient conc; A. b, C, D, E are all high order term coefficients. Table 2 below shows cone coefficients k and high-order term coefficients A, B, C, D and E of aspherical lens surfaces S1 to S2 and S11 to S12 that can be used in example 1.

TABLE 2

Flour mark

K

A

B

C

D

E

1

-0.7197

-3.1916E-03

-4.0439E-05

5.5623E-06

-1.9652E-07

2.3529E-09

2

-1.2333

-1.3076E-03

-6.7819E-05

1.2336E-05

-2.4732E-07

-3.0176E-09

11

-2.3230

-1.2344E-04

-1.0553E-07

-6.0510E-08

1.0233E-08

-5.0585E-10

12

-1.4204

-5.4351E-05

7.9590E-07

-2.0186E-07

1.5756E-08

-5.4778E-10

Table 3 below gives the total optical length TTL of the optical lens of embodiment 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 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 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 seventh lens L7 to the imaging surface IMA of the last lens), the on-axis distance D68 from the image-side surface S6 of the fourth lens L4 to the object-side surface S8 of the fifth lens L5, the center curvature radius R11-R12 of the object-side surface S3527 and the image-side surface S12, the combined value F585 of the focal length S573F of the first lens L56, the focal length F1 of the fifth lens L46l 5 and the sixth lens L6 of the fourth lens L4, The center radius of curvature R3 of the object-side surface S3 of the second lens L2 and the focal length value F7 of the seventh lens L7.

TABLE 3

TTL(mm)	30.0302	R12(mm)	-8.4767
				F(mm)	7.6760	F56(mm)	-65.2692
D(mm)	8.7876	R2(mm)	2.8056
				H(mm)	9.4180	R3(mm)	-7.9513
FOV(°)	80	F7(mm)	9.9813
				BFL(mm)	12.8971
d68(mm)	0.2139
				R11(mm)	17.3030

In the present embodiment, TTL/F is 3.9122 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; 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 0.0117; the BFL/TTL between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens is 0.4295; an on-axis distance d68 from the image side surface S6 of the fourth lens L4 to the object side surface S8 of the fifth lens L5 and an optical total length TTL of the optical lens satisfy d68/TTL of 0.0071; a central curvature radius R11 of the object-side surface S11 of the seventh lens L7 and a central curvature radius R12 of the image-side surface S12 of the seventh lens L7 satisfy (R11+ R12)/(R11-R12) ═ 0.3424; the total optical length TTL of the optical lens, the maximum field angle FOV of the optical lens and the image height H corresponding to the maximum field angle of the optical lens satisfy that TTL/H/FOV is 0.0399; a combined focal length value F56 of the fifth lens L5 and the sixth lens L6 and a whole group focal length value F of the optical lens satisfy | F56/F | ═ 8.5030; the central curvature radius R2 of the image-side surface S2 of the first lens L1 and the central curvature radius R3 of the object-side surface S3 of the second lens L2 satisfy (R2-R3)/(R2+ R3) ═ 2.0904: and F7/F1.3003 is satisfied between the focal length value F7 of the seventh lens L7 and the entire group focal length value F of the optical lens.

Example 2

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

As shown in fig. 2, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, 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). The following table 5 shows the conic coefficients k and the high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S1 to S2 and S11 to S12 in example 2. Table 6 below shows the total optical length TTL of the optical lens, the entire group focal length value F 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 optical back focus BFL of the optical lens, the on-axis distance D68 from the image-side surface S6 of the fourth lens L4 to the object-side surface S8 of the fifth lens L5, the central radius of curvature R11-R12 of the object-side surface S11 and the image-side surface S12 of the seventh lens L7, the combined focal length value F56 of the fifth lens L5 and the sixth lens L6, the central radius of curvature R2 of the image-side surface S573S 2 of the first lens L1, the central radius of curvature R3 of the object-side surface S3 of the second lens L2, and the focal length value F7 of the seventh lens L68628.

TABLE 4

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	4.6980	1.0666	1.80	41.00
2	2.8091	3.2519
					3	-7.9755	0.6000	1.52	64.21
4	6.7801	2.4812	1.70	30.05
					5	34.7271	3.4955	1.74	44.90
6	-11.0470	-0.5450
					STO	All-round	0.8011
8	20.4307	2.7850	1.50	81.59
					9	-6.7097	0.6000	1.76	27.55
10	309.1007	0.1000
					11	17.2508	2.4071	1.59	61.16
12	-8.4869	0.6000
					13	All-round	0.5500	1.52	64.21
14	All-round	11.1163
					15	All-round	0.5000	1.52	64.21
16	All-round	0.1250
					IMA	All-round

TABLE 5

TABLE 6

TTL(mm)	29.9348	R12(mm)	-8.4869
				F(mm)	7.6891	F56(mm)	-64.8609
D(mm)	8.7788	R2(mm)	2.8091
				H(mm)	9.4200	R3(mm)	-7.9755
FOV(°)	80	F7(mm)	9.9643
				BFL(mm)	12.8913
d68(mm)	0.2561
				R11(mm)	17.2508

In the present embodiment, TTL/F is 3.8932 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; 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 0.0116; the BFL/TTL between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens is 0.4306; an on-axis distance d68 from the image side surface S6 of the fourth lens L4 to the object side surface S8 of the fifth lens L5 and an optical total length TTL of the optical lens meet d68/TTL of 0.0086; a central curvature radius R11 of the object-side surface S11 of the seventh lens L7 and a central curvature radius R12 of the image-side surface S12 of the seventh lens L7 satisfy (R11+ R12)/(R11-R12) ═ 0.3405; the total optical length TTL of the optical lens, the maximum field angle FOV of the optical lens and the image height H corresponding to the maximum field angle of the optical lens satisfy that TTL/H/FOV is 0.0397; a combined focal length value F56 of the fifth lens L5 and the sixth lens L6 and a whole group focal length value F of the optical lens satisfy | F56/F | ═ 8.4355; the central curvature radius R2 of the image-side surface S2 of the first lens L1 and the central curvature radius R3 of the object-side surface S3 of the second lens L2 satisfy (R2-R3)/(R2+ R3) ═ 2.0875: and F7/F is 1.2959 is satisfied between the focal length value F7 of the seventh lens L7 and the focal length value F of the entire group of the optical lens.

Example 3

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

As shown in fig. 3, the optical lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, 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 3, where the radius of curvature R and the thickness T are both in units of millimeters (mm). The following table 8 shows the conic coefficients k and the high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S1 to S2 and S11 to S12 in example 3. Table 9 below gives the total optical length TTL of the optical lens, the entire group focal length value F 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 optical back focus BFL of the optical lens, the on-axis distance D68 from the image-side surface S6 of the fourth lens L4 to the object-side surface S8 of the fifth lens L5, the central radius of curvature R11-R12 of the object-side surface S11 and the image-side surface S12 of the seventh lens L7, the combined focal length value F56 of the fifth lens L5 and the sixth lens L6, the central radius of curvature R2 of the image-side surface S573S 2 of the first lens L1, the central radius of curvature R3 of the object-side surface S3 of the second lens L2, and the focal length value F7 of the seventh lens L68628.

TABLE 7

Flour mark	Radius of curvature R	Thickness T	Refractive index Nd	Abbe number Vd
					1	4.6607	1.0400	1.80	41.00
2	2.8168	3.2320
					3	-7.9773	0.6200	1.52	64.21
4	6.8064	2.4782	1.70	30.05
					5	35.2038	3.4918	1.74	44.90
6	-11.0485	-0.5450
					STO	All-round	0.9588
8	20.4597	2.6779	1.50	81.59
					9	-6.7120	0.6000	1.76	27.55
10	305.2132	0.1000
					11	17.1462	2.4696	1.59	61.16
12	-8.5066	0.6000
					13	All-round	0.5500	1.52	64.21
14	All-round	11.0270
					15	All-round	0.5000	1.52	64.21
16	All-round	0.1250
					IMA	All-round

TABLE 8

Flour mark

K

A

B

C

D

E

1

-0.7225

-3.1983E-03

-4.0592E-05

5.5660E-06

-1.9629E-07

2.3089E-09

2

-1.2341

-1.3127E-03

-6.8008E-05

1.2248E-05

-2.5511E-07

-2.8215E-09

11

-2.2789

-1.2243E-04

2.7093E-08

-5.7211E-08

1.0237E-08

-5.0921E-10

12

-1.4220

-5.4162E-05

7.2097E-07

-1.9966E-07

1.6147E-08

-5.5207E-10

TABLE 9

TTL(mm)	29.9253	R12(mm)	-8.5066
				F(mm)	7.6844	F56(mm)	-64.3302
D(mm)	8.7737	R2(mm)	2.8168
				H(mm)	9.4200	R3(mm)	-7.9773
FOV(°)	80	F7(mm)	9.9703
				BFL(mm)	12.8020
d68(mm)	0.4138
				R11(mm)	17.1462

In the present embodiment, TTL/F is 3.8943 between the total optical length TTL of the optical lens and the whole focal length F of the optical lens; 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 0.0116; the BFL/TTL between the optical back focus BFL of the optical lens and the optical total length TTL of the optical lens is 0.4278; an on-axis distance d68 from the image side surface S6 of the fourth lens L4 to the object side surface S8 of the fifth lens L5 and an optical total length TTL of the optical lens satisfy that d68/TTL is 0.0138; a central curvature radius R11 of the object-side surface S11 of the seventh lens L7 and a central curvature radius R12 of the image-side surface S12 of the seventh lens L7 satisfy (R11+ R12)/(R11-R12) ═ 0.3368; the total optical length TTL of the optical lens, the maximum field angle FOV of the optical lens and the image height H corresponding to the maximum field angle of the optical lens satisfy that TTL/H/FOV is 0.0397; a combined focal length value F56 of the fifth lens L5 and the sixth lens L6 and a whole group focal length value F of the optical lens satisfy | F56/F | ═ 8.3716; the central curvature radius R2 of the image-side surface S2 of the first lens L1 and the central curvature radius R3 of the object-side surface S3 of the second lens L2 satisfy (R2-R3)/(R2+ R3) ═ 2.0917: and F7/F1.2975 is satisfied between the focal length value F7 of the seventh lens L7 and the entire group focal length value F of the optical lens.

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

Watch 10

Conditions/examples	1	2	3
				TTL/F	3.9122	3.8932	3.8943
D/H/FOV	0.0117	0.0116	0.0116
				BFL/TTL	0.4295	0.4306	0.4278
d68/TTL	0.0071	0.0086	0.0138
				(R11+R12)/(R11-R12)	0.3424	0.3405	0.3368
TTL/H/FOV	0.0399	0.0397	0.0397
				\|F56/F\|	8.5030	8.4355	8.3716
(R2-R3)/(R2+R3)	-2.0904	-2.0875	-2.0917
				F7/F	1.3003	1.2959	1.2975

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

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

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

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

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

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

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.

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

3. 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.

4. An optical lens according to claim 1, characterized in that at least one of the first lens and the seventh lens is an aspherical mirror.

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

6. An optical lens according to any one of claims 1 to 5, 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 in degrees: (D × 180 °)/(H × FOV) ≦ 14.4.

7. An optical lens according to any one of claims 1-5, characterized in that between an optical back focus BFL of the optical lens and an optical total length TTL of the optical lens, it is satisfied that: BFL/TTL is more than or equal to 0.3.

8. An optical lens barrel according to any one of claims 1 to 5, wherein an on-axis distance d68 from the image-side surface of the fourth lens element to the object-side surface of the fifth lens element satisfies the following relationship with an overall optical length TTL of the optical lens barrel: d68/TTL is less than or equal to 0.025.

9. An optical lens barrel according to any one of claims 1 to 5, wherein a central radius of curvature R11 of an object side surface of the seventh lens and a central radius of curvature R12 of an image side surface of the seventh lens satisfy: the ratio of (R11+ R12)/(R11-R12) is not more than 0.2 and not more than 0.45.

10. The optical lens according to any one of claims 1 to 5, wherein an overall optical length TTL of the optical lens, a maximum field angle FOV of the optical lens in degrees, and an image height H corresponding to the maximum field angle of the optical lens satisfy: (TTL is multiplied by 180 degrees) and/(H is multiplied by FOV) is less than or equal to 36.

11. An optical lens according to any one of claims 1 to 5, characterized in that a combined focal length value F56 of the fifth lens and the sixth lens and a full set of focal length values F of the optical lens satisfy: the absolute value of F56/F is more than or equal to 7.8 and less than or equal to 9.

12. An optical lens barrel according to any one of claims 1 to 5, wherein the central radius of curvature R2 of the image side surface of the first lens and the central radius of curvature R3 of the object side surface of the second lens satisfy: 2.5-1.5 (R2-R3)/(R2+ R3).

13. An optical lens according to any one of claims 1 to 5, characterized in that a focal length value F7 of the seventh lens and a full group focal length value F of the optical lens satisfy: F7/F is less than or equal to 1.7.

14. 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 second lens and the sixth lens each have a negative optical power;

the third lens, the fourth lens, the fifth lens and the seventh lens each have a positive optical power;

the second lens, the third lens and the fourth lens are cemented to form a first cemented lens;

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

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

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

16. An optical lens barrel according to claim 14, wherein the second lens has both an object-side surface and an image-side surface which are concave.

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

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

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

20. An optical lens barrel according to claim 14, wherein the object side surface and the image side surface of the sixth lens are both concave.

21. An optical lens barrel according to claim 14, wherein the object side surface and the image side surface of the seventh lens element are convex.

22. An optical lens according to any one of claims 14 to 21, characterized in that at least one of the first lens and the seventh lens is an aspherical mirror.

23. An optical lens barrel according to any one of claims 14 to 21, wherein the first lens to the seventh lens are all glass lenses.

24. An optical lens according to any one of claims 14 to 21, 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 in degrees satisfy: (D × 180 °)/(H × FOV) ≦ 14.4.

25. An optical lens according to any one of claims 14-21, characterized in that between an optical back focus BFL of the optical lens and an optical total length TTL of the optical lens is satisfied: BFL/TTL is more than or equal to 0.3.

26. An optical lens element according to any one of claims 14 to 21, wherein an on-axis distance d68 from an image-side surface of the fourth lens element to an object-side surface of the fifth lens element satisfies the following relationship with an overall optical length TTL of the optical lens element: d68/TTL is less than or equal to 0.025.

27. An optical lens barrel according to any one of claims 14 to 21, wherein the central radius of curvature R11 of the object side surface of the seventh lens and the central radius of curvature R12 of the image side surface of the seventh lens satisfy: the ratio of (R11+ R12)/(R11-R12) is not more than 0.2 and not more than 0.45.

28. An optical lens according to any one of claims 14 to 21, wherein an overall optical length TTL of the optical lens, a maximum field angle FOV of the optical lens in degrees and an image height H corresponding to the maximum field angle of the optical lens satisfy: (TTL is multiplied by 180 degrees) and/(H is multiplied by FOV) is less than or equal to 36.

29. An optical lens according to any one of claims 14 to 21, characterized in that a combined focal length value F56 of the fifth lens and the sixth lens and a full set of focal length values F of the optical lens satisfy: the absolute value of F56/F is more than or equal to 7.8 and less than or equal to 9.

30. An optical lens element according to any one of claims 14 to 21, wherein the central radius of curvature R2 of the image side of the first lens element and the central radius of curvature R3 of the object side of the second lens element satisfy: 2.5-1.5 (R2-R3)/(R2+ R3).

31. An optical lens according to any one of claims 14 to 21, characterized in that a focal length value F7 of the seventh lens and a full group focal length value F of the optical lens satisfy: F7/F is less than or equal to 1.7.

32. An imaging apparatus comprising the optical lens of claim 1 or 14 and an imaging element for converting an optical image formed by the optical lens into an electric signal.