CN115032772A

CN115032772A - Large-aperture optical lens

Info

Publication number: CN115032772A
Application number: CN202210648581.4A
Authority: CN
Inventors: 王春燕
Original assignee: Liaoning Zhonglan Photoelectric Technology Co Ltd
Current assignee: Liaoning Zhonglan Photoelectric Technology Co Ltd
Priority date: 2022-06-09
Filing date: 2022-06-09
Publication date: 2022-09-09

Abstract

The invention relates to the technical field of optical lenses, in particular to a large-aperture optical lens. Which comprises, in order from an object side to an image side along an optical axis: a first lens with positive focal power, wherein the object side surface of the first lens is a convex surface; the object side surface of the second lens is a concave surface near the optical axis; the image side surface of the third lens is a concave surface at the position close to the optical axis; the object side surface of the fourth lens is a convex surface or a concave surface near the optical axis; the object side surface paraxial axis and the image side surface paraxial axis of the fifth lens are convex surfaces; the object side surface of the sixth lens is a convex surface at the position close to the optical axis; the optical lens further comprises a diaphragm positioned in front of the second lens; the aperture size of the optical lens is FNO < 1.45. The optical lens has the advantages of larger aperture, high quality resolving power, good optical performance and the like by reasonably distributing the focal power and the surface type of each lens, the central thickness of each lens and the on-axis distance between the lenses.

Description

Large-aperture optical lens

Technical Field

The invention relates to the technical field of optical lenses, in particular to a large-aperture optical lens.

Background

Along with the continuous development and the progress of intelligent products, people also have higher and higher requirements on the imaging quality of electronic equipment, and a great action point of the imaging quality lies in the size of the light transmission quantity, the light transmission quantity is large, the light which enters a lens in a wider range can be controlled, and meanwhile, the large aperture can also enable the depth of field of the lens to be wider, so that a shot object is clearer. The existing optical lens has the following defects:

1. the light transmission amount is small, the FNO is large, the characteristic of a large aperture cannot be met, the light transmission range is limited, and night scene shooting is not facilitated.

2. The depth of field range is short, and the imaging quality is poor.

Disclosure of Invention

In view of the above disadvantages and shortcomings of the prior art, the present invention provides a large aperture optical lens, which solves the problems of the prior art, such as small light transmission amount, short depth of field, and low resolving power.

In order to achieve the purpose, the invention adopts the main technical scheme that:

the present invention provides a large aperture optical lens assembly, in order from an object side to an image side comprising: a first lens with positive focal power, wherein the object side surface of the first lens is a convex surface; the object side surface of the second lens is a concave surface near the optical axis; the image side surface of the third lens is a concave surface at the position close to the optical axis; the object side surface of the fourth lens is a convex surface or a concave surface near the optical axis; the object side surface paraxial axis and the image side surface paraxial axis of the fifth lens are convex surfaces; the object side surface of the sixth lens is a convex surface at the position close to the optical axis; the optical lens further comprises a diaphragm, and the diaphragm is positioned in front of the second lens; the aperture size of the optical lens is FNO < 1.45.

Further, the optical lens satisfies the following relation: f4/| F3| < -1, wherein F3 is the focal length of the third lens and F4 is the focal length of the fourth lens.

Further, the optical lens satisfies the following relation: T56/T34>0.6, wherein T34 is the distance between the third lens and the fourth lens on the optical axis, and T56 is the distance between the fifth lens and the sixth lens on the optical axis.

Further, the optical lens satisfies the following relation: Σ AT/T34>4.5, where Σ AT is the sum of the distances between two adjacent lenses in the optical lens on the optical axis, and T34 is the distance between the third lens and the fourth lens on the optical axis.

Further, the optical lens satisfies the following relation: (| Sag51| + | Sag52|)/CT5>1, wherein Sag51 is the rise of the fifth lens at the maximum effective half aperture of the object side surface, Sag52 is the rise of the fifth lens at the maximum effective half aperture of the image side surface, and CT5 is the thickness of the fifth lens.

The invention has the beneficial effects that: the large-aperture optical lens provided by the invention adopts a plurality of lenses, such as 6 lenses, and adopts a mode of combining the aspheric plastic lenses, so that the optical lens has the advantages of large aperture, high quality resolving power, good optical performance and the like.

Drawings

Fig. 1 is a schematic structural diagram of a large-aperture optical lens according to embodiment 1 of the present invention;

FIG. 2A is a graph showing the axial chromatic aberration in example 1 of the present invention;

fig. 2B is a graph of astigmatism in embodiment 1 of the present invention;

FIG. 2C is a distortion curve chart of embodiment 1 of the present invention;

FIG. 2D is a graph showing the chromatic aberration of magnification in example 1 of the present invention;

fig. 3 is a schematic structural diagram of a large-aperture optical lens according to embodiment 2 of the present invention;

FIG. 4A is a graph showing the axial chromatic aberration in example 2 of the present invention;

fig. 4B is a graph of astigmatism for embodiment 2 of the present invention;

FIG. 4C is a distortion curve chart of embodiment 2 of the present invention;

FIG. 4D is a graph showing the chromatic aberration of magnification in example 2 of the present invention;

fig. 5 is a schematic structural diagram of a large-aperture optical lens according to embodiment 3 of the present invention;

FIG. 6A is a graph showing the axial chromatic aberration in example 3 of the present invention;

fig. 6B is a graph of astigmatism in embodiment 3 of the present invention;

FIG. 6C is a distortion curve chart of embodiment 3 of the present invention;

FIG. 6D is a graph of chromatic aberration of magnification in example 3 of the present invention.

In the figure: the lens comprises a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7 and an aperture ST.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.

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, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present invention.

In the drawings, the thickness, size and shape of the lenses 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 side surface is called the image side surface.

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

A large aperture optical lens, comprising: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6. The six lenses are arranged in sequence from the object side to the image side along the optical axis.

The first lens E1 is a positive power aspheric plastic lens, and its object-side surface is a convex surface.

The second lens E2 is a positive power aspheric plastic lens with a concave object-side surface near the optical axis.

The third lens E3 is a negative-power aspheric plastic lens, and the image-side surface of the lens is concave at the paraxial region.

The fourth lens E4 is a negative-power aspheric plastic lens, and the object-side surface of the lens can be convex or concave at the paraxial region.

The fifth lens E5 is a positive power aspheric plastic lens, and both the object-side paraxial region and the image-side paraxial region are convex.

The sixth lens E6 is a negative-power aspheric plastic lens, and the object-side surface paraxial part thereof is convex.

The optical lens also comprises a diaphragm ST, which is located before the second mirror E2. The optical lens satisfies the conditional expression FNO <1.45, wherein FNO is the aperture size of the optical lens. Limiting the size and position of the aperture can improve the resolution while satisfying a large aperture.

The optical lens meets the conditional expression F4/| F3| < -1, wherein F3 is the focal length of the third lens, and F4 is the focal length of the fourth lens. The reasonable distribution of the focal length can ensure the chromatic aberration of the optical imaging lens and improve the distortion.

The optical lens meets the conditional expression of T56/T34>0.6, wherein T34 is the distance between the third lens and the fourth lens on the optical axis, and T56 is the distance between the fifth lens and the sixth lens on the optical axis. The lens stray light can be properly improved by reasonably controlling the lens interval, and the compensation effect on the structural appearance is realized

The optical lens satisfies the conditional expression of Σ AT/T34>4.5, where Σ AT is the sum of the distances between two adjacent lenses in the lens on the optical axis, and T34 is the distance between the third lens and the fourth lens on the optical axis. The overall height of the lens is reasonably controlled, so that the miniaturization of the lens can be met, the overall layout of the lens is more reasonable, the later structure is compensated, and the requirement of production on the thickness of the lens is fundamentally met.

The optical lens meets the conditional expression (| Sag51| + | Sag52|)/CT5>1, wherein Sag51 is the rise of the fifth lens at the maximum effective half aperture of the object side surface, Sag52 is the rise of the fifth lens at the maximum effective half aperture of the image side surface, and CT5 is the thickness of the fifth lens. Sag is actually the lens rise, and suitable rise and thickness ratio can make the lens shape even, and the management and control of lens rise can improve the sensitivity and be favorable to machine-shaping.

The optical lens may further include a filter for correcting color deviation and/or a protective glass for protecting the photosensitive element on the imaging surface, as required by the specific case of the embodiment, and the filter or the protective glass may not be used in the case of no specific requirement.

The optical lens of the above embodiment may employ a plurality of lenses, for example, six lenses as described above. By reasonably distributing the focal power, the surface type, the central thickness of each lens, the on-axis distance between each lens and the like, the volume of the lens can be effectively reduced, the sensitivity of the lens can be reduced, the machinability of the lens can be improved, and the optical lens is more beneficial to production and processing. Meanwhile, the optical lens with the configuration has the beneficial effects of ultrathin thickness, ultra-wide angle, high imaging quality and the like.

In an embodiment of the present invention, the mirror surface of the partial lens is an aspherical mirror surface. The aspheric lens has the characteristics that: the curvature varies continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the lens center to the lens periphery, an aspherical lens has a better curvature radius characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated during imaging can be eliminated as much as possible, thereby improving the imaging quality.

Example 1

An optical lens according to embodiment 1 of the present invention is described below with reference to fig. 1, 2A to 2D. Fig. 1 shows a schematic structural diagram of an optical lens according to embodiment 1 of the present invention.

As shown in fig. 1, an optical lens according to an exemplary embodiment of the present invention includes, in order from an object side to an image side along an optical axis: a first lens E1, a diaphragm ST, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6 and a filter E7.

The first lens E1 is an aspheric plastic lens with positive power, and has a convex object-side surface S1 and a concave image-side surface S2. The second lens E2 is an aspheric plastic lens with positive power, and has a concave object-side surface S4 and a convex image-side surface S5. The third lens E3 is an aspheric plastic lens with negative power, and has a convex object-side surface S6 and a concave image-side surface S7. The fourth lens E4 is an aspheric plastic lens with negative power, and has a convex object-side surface S8 and a concave image-side surface S9. The fifth lens E5 is an aspheric plastic lens with positive power, and has a convex object-side surface S10 and a convex image-side surface S11. The sixth lens E6 is an aspheric plastic lens with positive power, and has a convex object-side surface S12 and a concave image-side surface S13. Filter E7 has an object side S14 and an image side S15. The light from the object sequentially passes through the respective surfaces S1 to S15, and is finally imaged on the imaging surface S16.

Table 1 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the optical lens of example 1, wherein the unit of the radius of curvature and the thickness are both millimeters (mm).

TABLE 1

As can be seen from table 1, the object-side surface and the image-side surface of any of the first lens element E1 through the sixth lens element E6 are aspheric. In the present embodiment, the profile x of each aspheric lens can be defined by, but is not limited to, the following aspheric formula:

wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex 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 (given in table 1); ai is a correction coefficient of the i-th order of the aspherical surface. Table 2 below gives the high-order coefficient A4, A6, A8, A10, A12, A14 which can be used for each of the aspherical mirror surfaces S1-S13 in example 1.

TABLE 2

Table 3 gives the total effective focal length f of the optical lens, the effective focal lengths f1 to f6 of the respective lenses, the total optical length TTL of the optical lens (i.e., the distance on the optical axis from the center of the object-side surface S1 of the first lens E1 to the imaging surface S16), and the maximum field angle FOV of the optical lens in embodiment 1.

TABLE 3

The optical lens in embodiment 1 satisfies:

the aperture size FNO of this embodiment is 1.44 and the diaphragm is located between the first and second lenses, satisfying FNO <1.45, the diaphragm being located before the second lens.

In this example, F4/| F3| -2.586 satisfies F4/| F3| < -1. Wherein F3 is the focal length of the third lens of the optical lens, and F4 is the focal length of the fourth lens of the optical lens.

In this embodiment, T56/T34 is 0.8422, and satisfies T56/T34>0.6, where T34 is the distance between the third lens and the fourth lens on the optical axis, and T56 is the distance between the fifth lens and the sixth lens on the optical axis.

In this embodiment, Σ AT/T34 is 5.32, and satisfies Σ AT/T34>4.5, where Σ AT is the sum of the distances between two adjacent lenses in the lens on the optical axis, and T34 is the distance between the third lens and the fourth lens on the optical axis.

In the embodiment (| Sag51| + | Sag52|)/CT5 ═ 1.08, satisfying (| Sag51| + | Sag52|)/CT5>1, where Sag51 is the rise of the fifth lens at the maximum effective half aperture of the object side, and Sag52 is the rise of the fifth lens at the maximum effective half aperture of the image side; CT5 is the thickness of the fifth lens.

In addition, fig. 2A shows an on-axis chromatic aberration curve of the optical lens of embodiment 1, which represents the deviation of the convergent focal points of light rays of different wavelengths after passing through the lens. Fig. 2B shows astigmatism curves representing meridional field curvature and sagittal field curvature of the optical lens of embodiment 1. Fig. 2C shows a distortion curve of the optical lens of embodiment 1, which represents distortion magnitude values in the case of different image heights. Fig. 2D shows a chromatic aberration of magnification curve of the optical lens of embodiment 1, which represents a deviation of different image heights on an image plane after light passes through the lens. As can be seen from fig. 2A to 2D, the optical lens system of embodiment 1 can achieve good image quality.

Example 2

An optical lens according to embodiment 2 of the present invention is described below with reference to fig. 3, 4A to 4D. 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 2 of the present invention.

As shown in fig. 3, the optical lens according to the exemplary embodiment of the present invention, in order from an object side to an image side along an optical axis, comprises: the stop ST, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6 and the filter E7.

The first lens E1 is an aspheric plastic lens with positive refractive power, and has a convex object-side surface S2 and a concave image-side surface S3. The second lens E2 is an aspheric plastic lens with positive power, and has a concave object-side surface S4 and a convex image-side surface S5. The third lens E3 is an aspheric plastic lens with negative power, and has a convex object-side surface S6 and a concave image-side surface S7. The fourth lens E4 is an aspheric plastic lens with negative power, and has a concave object-side surface S8 and a concave image-side surface S9. The fifth lens E5 is an aspheric plastic lens with positive power, and has a convex object-side surface S10 and a convex image-side surface S11. The sixth lens E6 is an aspheric plastic lens with negative power, and has a convex object-side surface S12 and a concave image-side surface S13. Filter E7 has an object side S14 and an image side S15. The light from the object sequentially passes through the respective surfaces S1 to S15, and is finally imaged on the imaging surface S16.

Table 4 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the optical lens of example 2, wherein the unit of the radius of curvature and the thickness are both millimeters (mm).

TABLE 4

As can be seen from table 4, in example 2, both the object-side surface and the image-side surface of any of the first lens E1 through the sixth lens E6 were aspheric. Table 5 shows the high-order term coefficients a4, a6, A8, a10, a12, a14, a16 usable for each of the aspherical mirror surfaces S1-S13 in example 2, wherein each aspherical surface type can be defined by formula (1) given in example 1 above.

TABLE 5

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

-1.48E-02

-4.76E-02

3.22E-02

-4.15E-02

-1.18E-02

3.06E-02

-9.50E-03

S2

-1.42E-01

-5.29E-03

-9.35E-02

2.32E-01

-2.06E-01

8.36E-02

-1.34E-02

S4

-5.83E-02

7.23E-03

-5.88E-03

1.35E-01

-1.32E-01

4.76E-02

-5.93E-03

S5

-9.18E-02

2.28E-01

-4.13E-01

5.10E-01

-3.83E-01

1.56E-01

-2.64E-02

S6

-5.78E-02

5.14E-02

-2.59E-01

3.01E-01

-1.83E-01

6.64E-02

-1.15E-02

S7

-3.92E-02

1.04E-01

-2.32E-01

2.34E-01

-1.25E-01

3.56E-02

-4.55E-03

S8

-9.50E-02

1.14E-01

-1.66E-03

-3.97E-02

1.47E-02

5.47E-04

-8.16E-04

S9

-1.27E-01

-2.47E-02

1.47E-01

-1.68E-01

1.09E-01

-3.89E-02

5.84E-03

S10

5.77E-02

-1.87E-01

2.52E-01

-2.32E-01

1.26E-01

-3.64E-02

4.21E-03

S11

1.60E-02

-6.45E-03

3.71E-04

-1.13E-02

9.04E-03

-2.36E-03

2.00E-04

S12

-1.15E-01

-4.29E-02

7.65E-02

-4.60E-02

1.54E-02

-2.68E-03

1.86E-04

S13

-1.02E-01

4.80E-02

-1.61E-02

3.49E-03

-4.68E-04

3.52E-05

-1.13E-06

Table 6 shows the total effective focal length f of the optical lens, the effective focal lengths f1 to f6 of the respective lenses, the total optical length TTL of the optical lens, and the maximum field angle FOV of the optical lens in example 2.

TABLE 6

The optical lens in embodiment 2 satisfies:

the aperture size FNO of this embodiment is 1.44 and the stop position is in front of the first lens, satisfying FNO <1.45, the stop being in front of the second lens.

In this example, F4/| F3| -2.097 satisfies F4/| F3| < -1. Wherein F3 is the focal length of the third lens of the optical lens, and F4 is the focal length of the fourth lens of the optical lens.

In this embodiment, T56/T34 is 0.724, and T56/T34>0.6 is satisfied, where T34 is the distance between the third lens and the fourth lens on the optical axis, and T56 is the distance between the fifth lens and the sixth lens on the optical axis.

In the embodiment, Σ AT/T34 is 4.948, and satisfies Σ AT/T34>4.5, where Σ AT is the sum of the distances between two adjacent lenses in the lens on the optical axis, and T34 is the distance between the third lens and the fourth lens on the optical axis.

In this embodiment (| Sag51| + | Sag52|)/CT5 ═ 1.167, satisfying (| Sag51| + | Sag52|)/CT5>1, where Sag51 is the rise of the fifth lens at the maximum effective half aperture of the object side, and Sag52 is the rise of the fifth lens at the maximum effective half aperture of the image side; CT5 is the thickness of the fifth lens.

Fig. 4A shows an on-axis chromatic aberration curve of the optical lens of embodiment 2, which represents the deviation of the convergent focal points of light rays of different wavelengths after passing through the lens. Fig. 4B shows astigmatism curves representing meridional field curvature and sagittal field curvature of the optical lens of embodiment 2. Fig. 4C shows a distortion curve of the optical lens of embodiment 2, which represents distortion magnitude values in the case of different image heights. Fig. 4D shows a chromatic aberration of magnification curve of the optical lens of embodiment 2, which represents a deviation of different image heights on an image plane after light passes through the lens. As can be seen from fig. 4A to 4D, the optical lens system of embodiment 2 can achieve good imaging quality.

Example 3

An optical lens according to embodiment 3 of the present invention is described below with reference to fig. 5, 6A to 6D. In this embodiment and the following embodiments, a description of parts similar to those of embodiment 1 will be omitted for the sake of brevity. Fig. 5 shows a schematic structural diagram of an optical lens according to embodiment 3 of the present invention.

As shown in fig. 5, the optical lens according to the exemplary embodiment of the present invention, in order from an object side to an image side along an optical axis, comprises: the stop ST, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6 and the filter E7.

The first lens E1 is an aspheric plastic lens with positive power, and has a convex object-side surface S2 and a concave image-side surface S3. The second lens E2 is an aspheric plastic lens with positive power, and has a concave object-side surface S4 and a convex image-side surface S5. The third lens E3 is an aspheric plastic lens with negative power, and has a convex object-side surface S6 and a concave image-side surface S7. The fourth lens E4 is an aspheric plastic lens with negative power, and has a concave object-side surface S8 and a concave image-side surface S9. The fifth lens E5 is an aspheric plastic lens with positive power, and has a convex object-side surface S10 and a convex image-side surface S11. The sixth lens E6 is an aspheric plastic lens with negative power, and has a convex object-side surface S12 and a concave image-side surface S13. Filter E7 has an object side S14 and an image side S15. The light from the object sequentially passes through the respective surfaces S1 to S15, and is finally imaged on the imaging surface S16.

Table 7 shows the surface type, radius of curvature, thickness, material, and conic coefficient of each lens of the optical lens of example 3, wherein the unit of the radius of curvature and the thickness are both millimeters (mm).

TABLE 7

As can be seen from table 7, in example 3, both the object-side surface and the image-side surface of any of the first lens E1 to the sixth lens E6 are aspheric. Table 8 shows the high-order term coefficients a4, a6, A8, a10, a12, a14, a16 usable for each of the aspherical mirror surfaces S1-S13 in example 3, wherein each aspherical surface type can be defined by formula (1) given in example 1 above.

TABLE 8

Flour mark

A4

A6

A8

A10

A12

A14

A16

S1

-1.77E-02

-4.66E-02

3.34E-02

-5.39E-02

2.85E-02

-2.50E-03

-1.13E-03

S2

-1.27E-01

-1.61E-02

-3.54E-02

1.28E-01

-1.22E-01

5.11E-02

-8.31E-03

S4

-4.07E-02

-4.86E-03

1.14E-02

1.02E-01

-1.19E-01

5.09E-02

-8.04E-03

S5

-7.43E-02

1.23E-01

-1.60E-01

1.83E-01

-1.38E-01

5.65E-02

-9.39E-03

S6

-3.05E-02

-7.89E-02

4.39E-02

-4.95E-02

4.36E-02

-1.51E-02

1.50E-03

S7

-4.41E-02

7.63E-02

-1.52E-01

1.44E-01

-7.36E-02

2.00E-02

-2.44E-03

S8

-7.32E-02

1.02E-01

-2.02E-02

-1.28E-02

2.82E-03

2.18E-03

-7.21E-04

S9

-1.31E-01

3.20E-02

3.27E-02

-4.89E-02

3.35E-02

-1.19E-02

1.73E-03

S10

3.60E-02

-1.08E-01

1.25E-01

-1.02E-01

4.94E-02

-1.27E-02

1.30E-03

S11

7.26E-03

-8.13E-03

1.55E-02

-2.29E-02

1.31E-02

-3.14E-03

2.69E-04

S12

-1.09E-01

-2.73E-02

5.35E-02

-3.14E-02

1.03E-02

-1.74E-03

1.17E-04

S13

-9.77E-02

4.56E-02

-1.51E-02

3.23E-03

-4.25E-04

3.11E-05

-9.62E-07

Table 8 shows the total effective focal length f of the optical lens, the effective focal lengths f1 to f6 of the respective lenses, the total optical length TTL of the optical lens, and the maximum field angle FOV of the optical lens in example 3.

TABLE 9

The optical lens in embodiment 3 satisfies:

the aperture size FNO of this embodiment is 1.43 and the stop position is in front of the first mirror, satisfying FNO <1.45, the stop being in front of the second mirror.

In this example, F4/| F3| -1.952 satisfies F4/| F3| < -1. Wherein F3 is the focal length of the third lens, and F4 is the focal length of the fourth lens.

In this embodiment, T56/T34 is 0.6697, and satisfies T56/T34>0.6, where T34 is the distance between the third lens and the fourth lens on the optical axis, and T56 is the distance between the fifth lens and the sixth lens on the optical axis.

In this embodiment, Σ AT/T34 is 5.06, and satisfies Σ AT/T34>4.5, where Σ AT is the sum of the distances between two adjacent lenses in the lens on the optical axis, and T34 is the distance between the third lens and the fourth lens on the optical axis.

In the embodiment (| Sag51| + | Sag52|)/CT5 ═ 1.06, satisfying (| Sag51| + | Sag52|)/CT5>1, where Sag51 is the rise of the fifth lens at the maximum effective half aperture of the object side, and Sag52 is the rise of the fifth lens at the maximum effective half aperture of the image side; CT5 is the thickness of the fifth lens.

Fig. 6A shows on-axis chromatic aberration curves of the optical lens of embodiment 3, which represent the deviation of the convergent focal points of light rays of different wavelengths after passing through the lens. Fig. 6B shows astigmatism curves representing meridional field curvature and sagittal field curvature of the optical lens of embodiment 3. Fig. 6C shows a distortion curve of the optical lens of embodiment 3, which represents distortion magnitude values in the case of different image heights. Fig. 6D shows a chromatic aberration of magnification curve of the optical lens of embodiment 3, which represents a deviation of different image heights on an image plane after light passes through the lens. As can be seen from fig. 6A to 6D, the optical lens system of embodiment 3 can achieve good imaging quality.

Although embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and not to be construed as limiting the present invention and that those skilled in the art may make modifications, alterations, substitutions and alterations to the above embodiments within the scope of the present invention.

Claims

1. A large aperture optical lens, in order from an object side to an image side, comprising:

a first lens with positive focal power, wherein the object side surface of the first lens is a convex surface;

the object side surface of the second lens is a concave surface near the optical axis;

the image side surface of the third lens is a concave surface at the position close to the optical axis;

the object side surface of the fourth lens is a convex surface or a concave surface near the optical axis;

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

the object side surface of the sixth lens is a convex surface at the position close to the optical axis;

the optical lens further comprises a diaphragm, and the diaphragm is positioned in front of the second lens;

the aperture size of the optical lens is FNO < 1.45.

2. A large aperture optical lens according to claim 1, wherein the optical lens satisfies the following relation:

F4/|F3|<-1

wherein, F3 is the focal length of the third lens, and F4 is the focal length of the fourth lens.

3. A large aperture optical lens according to claim 1, wherein the optical lens satisfies the following relation:

T56/T34>0.6

wherein, T34 is the distance between the third lens and the fourth lens on the optical axis, and T56 is the distance between the fifth lens and the sixth lens on the optical axis.

4. A large aperture optical lens according to claim 1, wherein the optical lens satisfies the following relation:

∑AT/T34>4.5

Σ AT is the sum of the distances between two adjacent lenses in the optical lens on the optical axis, and T34 is the distance between the third lens and the fourth lens on the optical axis.

5. A large aperture optical lens according to claim 1, wherein the optical lens satisfies the following relation:

(|Sag51|+|Sag52|)/CT5>1

wherein, Sag51 is the rise of the fifth lens at the maximum effective half aperture of the object side surface, Sag52 is the rise of the fifth lens at the maximum effective half aperture of the image side surface, and CT5 is the thickness of the fifth lens.