CN109425959B - Optical lens - Google Patents

Abstract

The present application discloses an optical lens, which sequentially comprises, from an object side to an image side along an optical axis: the zoom lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The second lens can be glued with the third lens, the fourth lens can be glued with the fifth lens, and the seventh lens can be glued with the eighth lens; wherein the first lens, the second lens, the fifth lens, the sixth lens and the eighth lens may all have positive optical power; and the third lens, the fourth lens and the seventh lens may all have negative optical power.

Description

Optical lens

Technical Field

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

Background

As the demand for imaging device (e.g., camera) pixels increases, the corresponding chip size increases, resulting in an increase in the overall size of the lens. Meanwhile, in some special applications, such as night use of a vehicle-mounted lens, in order to improve the effect of night use of the lens, the clear aperture of the lens generally needs to be increased, which also results in an increase in the aperture of the lens.

However, for some applications with limited mounting locations, a small size lens is required to meet the mounting requirements. For example, an on-vehicle lens needs to be mounted inside a windshield, and since there is a risk of interference with the windshield and the mounting position is limited, a special lens design needs to be used to meet the requirements of a small aperture, a small size, and a high resolution.

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, a seventh lens, and an eighth lens. The second lens can be glued with the third lens, the fourth lens can be glued with the fifth lens, and the seventh lens can be glued with the eighth lens; wherein the first lens, the second lens, the fifth lens, the sixth lens and the eighth lens may all have positive optical power; and the third lens, the fourth lens and the seventh lens may all have negative optical power.

In one embodiment, the object side surfaces of the first lens element, the second lens element and the third lens element can be convex, and the image side surfaces of the first lens element, the second lens element and the third lens element can be concave.

In one embodiment, both the object-side and image-side surfaces of the fourth and seventh lenses may be concave.

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

In one embodiment, at least more than half of the lenses of the optical lens may be aspheric lenses.

In one embodiment, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may all be aspheric lenses.

In one embodiment, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may all be glass aspheric lenses.

In one embodiment, the image-side surface of the eighth lens element may have an inflection point, and the paraxial region may be convex and the paraxial region may be concave.

In one embodiment, a distance TTL between a center of an object side surface of the first lens element and an imaging surface of the optical lens on an optical axis and a full-group focal length value f of the optical lens may satisfy: TTL/f is less than or equal to 3.

In one embodiment, D/h/FOV ≦ 0.08 may be satisfied, where FOV is the maximum field angle of the optical lens; d is the maximum light-passing aperture of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens; and h is the image height corresponding to the maximum field angle 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 zoom lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. Wherein the first lens, the second lens, the fifth lens, the sixth lens and the eighth lens may all have positive optical power; the third lens, the fourth lens and the seventh lens may all have negative optical power; and the distance TTL from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis and the whole group of focal length values f of the optical lens can satisfy the following conditions: TTL/f is less than or equal to 3.

In one embodiment, the object side surfaces of the first lens element, the second lens element and the third lens element can be convex, and the image side surfaces of the first lens element, the second lens element and the third lens element can be concave.

In one embodiment, both the object-side and image-side surfaces of the fourth and seventh lenses may be concave.

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

In one embodiment, at least more than half of the lenses of the optical lens may be aspheric lenses.

In one embodiment, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may all be aspheric lenses.

In one embodiment, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may all be glass aspheric lenses.

In one embodiment, the second lens may be cemented with the third lens.

In one embodiment, the fourth lens may be cemented with the fifth lens.

In one embodiment, the seventh lens may be cemented with the eighth lens.

In one embodiment, the image-side surface of the eighth lens element may have an inflection point, and the paraxial region may be convex and the paraxial region may be concave.

In one embodiment, D/h/FOV ≦ 0.08 may be satisfied, where FOV is the maximum field angle of the optical lens; d is the maximum light-passing aperture of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens; and h is the image height corresponding to the maximum field angle of the optical lens.

The optical lens adopts eight lenses, for example, and realizes the beneficial effects of small caliber, miniaturization, high pixel and good temperature performance of the optical lens by optimally setting the shapes of the lenses, reasonably distributing the focal power of each lens, adopting a glass lens, an aspheric lens, forming a cemented lens and the like.

Drawings

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

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

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

Detailed Description

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

It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens, 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, eight lenses having optical power, i.e., a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens. The eight lenses are arranged in order from an object side to an image side along an optical axis.

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

The first lens element can have a positive power, and can have a convex object-side surface and a concave image-side surface. The first lens can collect light rays with a large field of view as far as possible, and enables the collected light rays to enter the rear optical system, so that the aperture of the optical system is favorably reduced. In practical application, considering the outdoor installation and use environment of the vehicle-mounted lens, the vehicle-mounted lens can be in severe weather such as rain and snow, 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, and the influence on the imaging quality of the lens is reduced.

The second lens element can have a positive power, and can have a convex object-side surface and a concave image-side surface. The second lens compresses the light collected by the first lens, so that the light enters a rear optical system.

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

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

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

The eighth lens element may have a positive optical power and the object-side surface thereof may be convex. Alternatively, the image-side surface of the eighth lens element may have an inflection point, and the paraxial region may be convex and the paraxial region may be concave.

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. By introducing the first cemented lens consisting of the second lens and the third lens, the chromatic aberration influence can be eliminated, and the tolerance sensitivity of the system is reduced; meanwhile, the cemented second lens and third lens may also retain a partial chromatic aberration to balance the entire chromatic aberration of the optical system. In the first cemented lens, the second lens close to the object side has positive focal power, and the third lens close to the image side has negative focal power, so that the arrangement is favorable for further and smoothly transiting the light rays passing through the first lens to the fourth lens, thereby reducing the aperture and the size of the lens, shortening the optical total length of the system and being favorable for realizing the miniaturization of the lens.

In addition, the fourth lens and the fifth lens can also 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. The second cemented lens composed of the fourth lens and the fifth lens has the advantages of eliminating chromatic aberration by itself, reducing tolerance sensitivity and residual chromatic aberration of the system to balance the overall chromatic aberration of the optical system, and the like. In the second cemented lens, the fourth lens close to the object side has negative focal power, and the fifth lens close to the image side has positive focal power, so that the arrangement is favorable for further diverging and converging the front light rays and then transferring the front light rays to a rear optical system, the reduction of the rear port diameter and the rear end size of the lens and the shortening of the optical total length of the system are favorable, and the miniaturization of the lens is favorably realized.

In addition, the seventh lens and the eighth lens may also be combined into a third cemented lens by cementing the image-side surface of the seventh lens with the object-side surface of the eighth lens. The third cemented lens composed of the seventh lens and the eighth lens has the advantages of eliminating chromatic aberration by itself, reducing tolerance sensitivity and residual chromatic aberration of the system to balance the overall chromatic aberration of the optical system, and the like. In the third cemented lens, the seventh lens close to the object side has negative focal power, and the eighth lens close to the image side has positive focal power, so that the arrangement is favorable for further diverging and converging the front light rays, the front light rays are smoothly transited to the imaging surface of the rear optical system, the reduction of the rear port diameter and the rear end size of the lens and the shortening of the total optical length of the system are favorable, and the miniaturization of the lens is favorably realized.

The lenses are glued to form the cemented lens, so that the air space of each lens in the cemented lens can be minimized, the whole optical system is compact, and the requirement of system miniaturization is met. Furthermore, the gluing of the lenses reduces tolerance sensitivity problems of the lens units due to tilt/decentration during assembly. In an exemplary embodiment, a stop for limiting the light beam may be disposed, for example, between the third lens and the fourth lens (i.e., between the first cemented lens and the second cemented lens) to further improve the imaging quality of the lens. When the diaphragm is arranged between the third lens and the fourth lens, incident light rays can be shrunk, the aperture of the lens can be reduced, and meanwhile, the effect of balancing the aperture of the front end and the rear end of the whole lens can be achieved.

The sixth lens is a converging lens, further converges the light passing through the cemented lens, adjusts the light to smoothly and stably transit to the rear optical system, and can balance the spherical aberration introduced by the front lens.

An overall optical length TTL (i.e., a distance on an optical axis from a center of an object side surface of the first lens to an imaging surface of the optical lens) of the optical lens and a whole group focal length value f of the optical lens may satisfy TTL/f.ltoreq.3, and more specifically, TTL and f may further satisfy TTL/f.ltoreq.2.19. The condition formula TTL/f is less than or equal to 3, and the miniaturization characteristic of the lens can be realized.

The maximum field angle FOV of the optical lens, the maximum light-passing 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 can satisfy the following conditions: D/h/FOV ≦ 0.08, more specifically D, h and FOV may further satisfy D/h/FOV ≦ 0.035. The conditional expression D/h/FOV is less than or equal to 0.08, and the small caliber of the front end of the lens can be ensured.

In an exemplary embodiment, the lens used in the optical lens may be a plastic lens, or may be a glass lens. Because the thermal expansion coefficient of the lens made of plastic is large, when the variation range of the environmental temperature used by the lens is large, the lens made of plastic can cause large influence on the overall performance of the lens. And the glass lens can reduce the influence of temperature on the performance of the lens. In an exemplary embodiment, at least more than half of the lenses of the optical lens may be arranged as 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. For example, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens can be arranged as aspheric lenses, and further arranged as glass aspheric lenses, so that the resolution can be improved, the aperture of the front end of the lens can be reduced, the radial volume of the lens can be reduced, and the lens can be guaranteed to maintain perfect resolution in a large temperature change range, thereby being beneficial to realizing the requirements of good temperature performance, small aperture and miniaturization.

The optical lens according to the above-described embodiment of the present application may employ a plurality of lenses, for example, eight lenses as described above. The light rays are adjusted through reasonable arrangement of the lenses so as to meet the requirements of small caliber and short TTL. The diaphragm is arranged on the front part of the optical lens, so that the front end aperture and the rear end aperture of the whole lens are close to each other. And the use of the cemented lens can eliminate the lens spacing on one hand and the influence of chromatic aberration on the other hand, thereby improving the resolution, making the image clear and reducing the misjudgment risk of software. Therefore, according to the optical lens of the above embodiment of the present application, not only the total optical length of the lens can be shortened to achieve miniaturization, but also the resolution performance of the lens can be improved, the resolution definition can be improved, the lens has better imaging quality, the image is clear, and the risk of software misjudgment can be reduced, so that the lens can better meet the requirements of the vehicle-mounted 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 eight lenses are exemplified in the embodiment, the optical lens is not limited to include eight lenses. The optical lens may also include other numbers of lenses, if desired.

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

Example 1

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

As shown in fig. 1, the optical lens includes, in order from an object side to an image side along an optical axis, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

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

The second lens L2 is a meniscus lens with positive power, with the object side S3 being convex and the image side S4 being concave. The third lens L3 is a meniscus lens with negative power, with the object side S4 being convex and the image side S5 being concave. Wherein, the second lens L2 and the third lens L3 are cemented to form a first cemented lens.

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

The sixth lens element L6 is a biconvex lens with positive refractive power, and has a convex object-side surface S10 and a convex image-side surface S11.

The seventh lens L7 is a biconcave lens with negative power, and has a concave object-side surface S12 and a concave image-side surface S13. The eighth lens element L8 has positive power, a convex object-side surface S13, a convex image-side surface S14, a convex paraxial region, and a concave surface. Wherein the seventh lens L7 and the eighth lens L8 are cemented to constitute a third cemented lens.

Optionally, the optical lens may further include a filter L9 and/or a protective lens L9' having an object side S15 and an image side S16. Color filters may be used to correct for color deviations. The protective lens may be used to protect an image sensing chip located at the imaging plane IMA. Optionally, light from the object passes through each of the surfaces S1-S16 in sequence and is ultimately imaged onto the imaging plane IMA.

In the optical lens of the present embodiment, a stop STO may be provided between the third lens L3 and the fourth lens L4 (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 eight 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 realize the effects of reducing the total optical length and expanding the field angle while ensuring a large imaging size and high pixels. Each aspherical surface type Z is defined by the following formula:

wherein Z is the distance rise from the vertex of the aspheric surface when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c being 1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is the conic coefficient conc; A. b, C, D, E are all high order term coefficients. Table 2 below shows cone coefficients k and high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S7, S8, S9, S10, S11, S12, S13, and S14 in example 1.

TABLE 2

Flour mark

K

A

B

C

D

E

7

-1.8450

2.1898E-05

1.2493E-06

3.9953E-08

-3.6980E-09

5.5626E-11

8

-3.3300

6.2050E-04

-2.1377E-05

5.3063E-07

-5.8599E-09

2.4467E-11

9

-3.3421

6.0382E-05

2.0729E-07

-8.7254E-09

2.9193E-10

-2.1695E-12

10

-2.4216

-4.6803E-05

-4.9631E-07

8.6834E-09

-1.6889E-11

-4.4413E-14

11

7.3671

-1.4955E-04

1.6861E-07

9.7482E-09

-6.3864E-11

3.2467E-13

12

-25.4736

7.5434E-05

-5.4138E-07

1.6796E-09

4.1508E-11

-1.2929E-13

13

-7.9222

-6.1447E-05

1.7653E-06

7.3877E-09

7.5586E-11

-1.4906E-12

14

0.0000

1.9867E-04

-1.8761E-07

7.9675E-09

-9.1127E-11

2.9054E-13

Table 3 below gives 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 of example 1, the image height h corresponding to the maximum field angle of the optical lens, the maximum field angle FOV of the optical lens, the total optical length TTL of the optical lens (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface IMA), and the entire group focal length value f of the optical lens.

TABLE 3

Parameter(s)	TTL(mm)	f(mm)	D(mm)	h(mm)	FOV(°)
						Numerical value	51.41	23.54	20.12	15.80	36.8

In the present embodiment, D/h/FOV is 0.035 between 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; and the total optical length TTL of the optical lens and the whole group focal length value f of the optical lens satisfy that TTL/f is 2.184.

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, a seventh lens L7, and an eighth lens L8.

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

The second lens L2 is a meniscus lens with positive power, with the object side S3 being convex and the image side S4 being concave. The third lens L3 is a meniscus lens with negative power, with the object side S4 being convex and the image side S5 being concave. Wherein, the second lens L2 and the third lens L3 are cemented to form a first cemented lens.

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

The sixth lens element L6 is a biconvex lens with positive refractive power, and has a convex object-side surface S10 and a convex image-side surface S11.

The seventh lens L7 is a biconcave lens with negative power, and has a concave object-side surface S12 and a concave image-side surface S13. The eighth lens element L8 has positive power, a convex object-side surface S13, a convex image-side surface S14, a convex paraxial region, and a concave surface. Wherein the seventh lens L7 and the eighth lens L8 are cemented to constitute a third cemented lens.

Optionally, the optical lens may further include a filter L9 and/or a protective lens L9' having an object side S15 and an image side S16. Color filters may be used to correct for color deviations. The protective lens may be used to protect an image sensing chip located at the imaging plane IMA. Optionally, light from the object passes through each of the surfaces S1-S16 in sequence and is ultimately imaged onto the imaging plane IMA.

In the optical lens of the present embodiment, a stop STO may be provided between the third lens L3 and the fourth lens L4 (i.e., between the first cemented lens and the second cemented lens) to improve the imaging quality.

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 cone coefficients k and high-order term coefficients A, B, C, D and E that can be used for the aspherical lens surfaces S7, S8, S9, S10, S11, S12, S13, and S14 in example 2. Table 6 below gives 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 of example 2, the image height h corresponding to the maximum field angle of the optical lens, the maximum field angle FOV of the optical lens, the total optical length TTL of the optical lens (i.e., the on-axis distance from the center of the object-side surface S1 of the first lens L1 to the imaging surface IMA), and the entire group focal length value f of the optical lens. Wherein each aspherical surface type can be defined by the formula (1) given in the above-described embodiment 1.

TABLE 4

TABLE 5

Flour mark

K

A

B

C

D

E

7

-1.6630

1.0846E-05

2.3955E-06

1.5130E-08

-6.0708E-09

1.2477E-10

8

-3.3589

6.1953E-04

-2.1578E-05

5.4339E-07

-3.3230E-09

-9.6039E-12

9

-3.4272

6.1467E-05

2.1362E-07

-6.3803E-09

3.3730E-10

-1.2465E-12

10

-1.7713

-3.5134E-05

-2.4319E-07

1.1191E-08

-2.7768E-12

-1.1260E-13

11

20.7541

-1.6168E-04

1.2702E-07

1.0348E-08

-4.7512E-11

6.4120E-13

12

-31.2425

7.3332E-05

-7.4631E-07

-1.4036E-09

1.6187E-11

-7.7531E-14

13

-15.2322

-1.2989E-04

1.0340E-06

7.9245E-09

2.0400E-10

2.1269E-13

14

0.0000

2.2341E-04

1.2020E-07

6.5726E-09

-1.4871E-10

1.3388E-12

TABLE 6

Parameter(s)	TTL(mm)	f(mm)	D(mm)	h(mm)	FOV(°)
						Numerical value	49.35	23.60	20.21	16.05	36.8

In the present embodiment, D/h/FOV is 0.034 between the maximum light-passing 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, and the maximum field angle FOV of the optical lens; and the total optical length TTL of the optical lens and the total focal length f of the optical lens satisfy that TTL/f is 2.091.

In summary, examples 1 to 2 each satisfy the relationship shown in table 7 below.

TABLE 7

Conditional expression (A) example	1	2
			TTL/f	2.184	2.091
D/h/FOV	0.035	0.034

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 (19)

1. An optical lens in which the number of lenses having optical power is eight, which are: the optical lens assembly comprises a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element, wherein the first lens element to the eighth lens element are arranged in order from an object side to an image side along an optical axis;

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

the second lens is cemented with the third lens,

the fourth lens is cemented with the fifth lens,

the seventh lens is cemented with the eighth lens,

the first lens, the second lens, the fifth lens, the sixth lens, and the eighth lens all have positive optical power; and

the third lens, the fourth lens and the seventh lens all have negative optical power;

the object side surfaces of the first lens, the second lens and the third lens are convex surfaces, and the image side surfaces of the first lens, the second lens and the third lens are concave surfaces;

the object side surface and the image side surface of the fifth lens and the sixth lens are convex surfaces.

2. An optical lens barrel according to claim 1, wherein the object side surface and the image side surface of the fourth lens and the seventh lens are both concave.

3. An optical lens according to any one of claims 1 to 2, characterized in that at least more than half of the lenses of the optical lens are aspherical lenses.

4. An optical lens according to claim 3, characterized in that the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are all aspherical lenses.

5. An optical lens according to claim 4, wherein the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are all glass aspherical lenses.

6. An optical lens barrel according to any one of claims 1 to 2, wherein the image side surface of the eighth lens element has an inflection point, and is convex in a paraxial region and concave in a paraxial region.

7. An optical lens barrel according to any one of claims 1 to 2, wherein a distance TTL between a center of an object side surface of the first lens and an imaging surface of the optical lens on the optical axis and a full group focal length value f of the optical lens satisfy: TTL/f is less than or equal to 3.

8. The optical lens according to any one of claims 1 to 2, characterized in that (D180 °/(h FOV) ≦ 14.40 is satisfied,

wherein the FOV is the maximum field angle of the optical lens;

d is the maximum light-passing aperture of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens; and

h is the image height corresponding to the maximum field angle of the optical lens.

9. An optical lens in which the number of lenses having optical power is eight, which are: the optical lens assembly comprises a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element, a seventh lens element and an eighth lens element, wherein the first lens element to the eighth lens element are arranged in order from an object side to an image side along an optical axis;

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

the first lens, the second lens, the fifth lens, the sixth lens, and the eighth lens all have positive optical power;

the third lens, the fourth lens and the seventh lens all have negative optical power;

the object side surface and the image side surface of the fifth lens and the sixth lens are convex surfaces; and

the distance TTL from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis and the whole group of focal length values f of the optical lens satisfy the following condition: TTL/f is less than or equal to 3.

10. An optical lens barrel according to claim 9, wherein the object side surfaces of the first lens element, the second lens element and the third lens element are convex, and the image side surfaces thereof are concave.

11. An optical lens barrel according to claim 9, wherein the object side surface and the image side surface of the fourth lens and the seventh lens are concave.

12. An optical lens according to any one of claims 9 to 11, characterized in that at least more than half of the lenses of the optical lens are aspherical lenses.

13. An optical lens barrel according to claim 12, wherein the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are aspherical lenses.

14. An optical lens barrel according to claim 13, wherein the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are all glass aspherical lenses.

15. An optical lens according to any one of claims 9 to 11, characterized in that the second lens is cemented with the third lens.

16. An optical lens according to any one of claims 9 to 11, characterized in that the fourth lens is cemented with the fifth lens.

17. An optical lens according to any one of claims 9 to 11, characterized in that the seventh lens is cemented with the eighth lens.

18. An optical lens barrel according to any one of claims 9 to 11, wherein the image side surface of the eighth lens element has an inflection point, and is convex in a paraxial region and concave in a paraxial region.

19. An optical lens according to any of claims 9 to 11, characterized in that (D180 °/(h FOV) ≦ 14.40 is satisfied,

wherein the FOV is the maximum field angle of the optical lens;

d is the maximum light-passing aperture of the object-side surface of the first lens corresponding to the maximum field angle of the optical lens; and

h is the image height corresponding to the maximum field angle of the optical lens.

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