CN113791489B

CN113791489B - Optical lens

Info

Publication number: CN113791489B
Application number: CN202111351848.5A
Authority: CN
Inventors: 王义龙; 徐宇轩; 曾昊杰; 曾吉勇
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2021-11-16
Filing date: 2021-11-16
Publication date: 2022-03-29
Anticipated expiration: 2041-11-16
Also published as: CN113791489A

Abstract

The invention provides an optical lens, which comprises the following components in sequence from an object side to an image side along an optical axis: the image side surface of the first lens is a concave surface; a second lens having a positive optical power; a diaphragm; a third lens with positive focal power, wherein the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; a fourth lens with negative focal power, wherein the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface; a fifth lens element with positive refractive power having a concave object-side surface and a convex image-side surface; a sixth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a seventh lens having a refractive power, an image-side surface of which is concave; the maximum field angle FOV of the optical lens satisfies: the FOV is more than or equal to 120 degrees. Through this application for optical lens has high pixel, miniaturized, big light ring and the high advantage of imaging quality.

Description

Optical lens

Technical Field

The invention relates to the technical field of lens imaging, in particular to an optical lens.

Background

At present, a camera lens has become a standard configuration of an electronic device (such as a smart phone and a camera), and even the camera lens has become an index of primary consideration when a consumer purchases the electronic device. In recent years, with the development of design level and manufacturing technology, the size, weight and performance of the imaging lens have been reduced.

The higher the mobile phone is, the higher the pixels of the mobile phone are, the smaller the size of the chip pixel points matched with the camera is, and the information obtained by photographing is increased.

However, it is difficult for the conventional imaging lens to satisfy the characteristics of high pixel, miniaturization, large aperture and high imaging quality at the same time.

Disclosure of Invention

Accordingly, an object of the present invention is to provide an optical lens, which can at least overcome at least one of the above-mentioned drawbacks in the prior art, so as to meet the design requirements of the optical lens of the electronic device.

An optical lens, comprising, in order from an object side to an image side along an optical axis:

the image side surface of the first lens is a concave surface;

a second lens having a positive optical power;

a diaphragm;

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

a fourth lens with negative focal power, wherein the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface;

a fifth lens element with positive refractive power having a concave object-side surface and a convex image-side surface;

a sixth lens element with negative refractive power having a convex object-side surface and a concave image-side surface;

a seventh lens having a refractive power, an image-side surface of which is concave;

wherein a maximum field angle FOV of the optical lens satisfies:

FOV≥120°；

the distance TTL from the object side surface of the first lens to the imaging surface on the optical axis and the half ImgH of the diagonal length of the effective pixel area on the imaging surface of the optical lens meet the following conditions:

1.10＜TTL/ImgH＜1.70；

the total effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: f/EPD is more than or equal to 2.2 and less than or equal to 2.23.

According to the optical lens provided by the invention, through reasonably matching the combination of the lens shape and the focal power among the lenses, the size of the whole optical lens is effectively reduced, the effect of clear imaging of the large aperture is realized while the optical lens is miniaturized, the optical lens has the advantages of miniaturization, high imaging quality and large aperture, has good applicability to portable electronic equipment, and can effectively improve the shooting experience of a user.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural diagram of an optical lens system according to a first embodiment of the present invention;

FIG. 2 is a field curvature graph of an optical lens according to a first embodiment of the present invention;

FIG. 3 is a diagram illustrating a distortion curve of an optical lens according to a first embodiment of the present invention;

FIG. 4 is a graph illustrating axial aberrations of an optical lens according to a first embodiment of the present invention;

FIG. 5 is a vertical axis chromatic aberration diagram of an optical lens according to a first embodiment of the present invention;

FIG. 6 is a schematic structural diagram of an optical lens system according to a second embodiment of the present invention;

FIG. 7 is a field curvature graph of an optical lens according to a second embodiment of the present invention;

FIG. 8 is a distortion graph of an optical lens in a second embodiment of the present invention;

FIG. 9 is a graph illustrating axial aberrations of an optical lens according to a second embodiment of the present invention;

FIG. 10 is a vertical axis chromatic aberration diagram of an optical lens according to a second embodiment of the present invention;

FIG. 11 is a schematic structural diagram of an optical lens assembly according to a third embodiment of the present invention;

FIG. 12 is a field curvature graph of an optical lens according to a third embodiment of the present invention;

fig. 13 is a distortion graph of an optical lens in a third embodiment of the present invention;

fig. 14 is a graph showing axial aberration of an optical lens in a third embodiment of the present invention;

FIG. 15 is a vertical axis chromatic aberration diagram of an optical lens according to a third embodiment of the present invention;

FIG. 16 is a schematic structural diagram of an optical lens system according to a fourth embodiment of the present invention;

fig. 17 is a field curvature graph of an optical lens in a fourth embodiment of the present invention;

fig. 18 is a distortion graph of an optical lens in a fourth embodiment of the present invention;

fig. 19 is a graph showing axial aberration of an optical lens in the fourth embodiment of the present invention;

fig. 20 is a vertical axis chromatic aberration diagram of an optical lens according to a fourth embodiment of the present invention.

Description of the main element symbols:

the following detailed description will further illustrate the invention in conjunction with the above-described figures.

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 embodiments of the application and does not limit the scope of the 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 without departing from the teachings of the present invention.

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 of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

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 invention, "may" be used to mean "one or more embodiments of the present invention. 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 embodiment of the present application includes, in order from an object side to an imaging surface: the lens comprises a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens. The seven lenses are arranged in sequence from the object side to the image side along the optical axis.

In some embodiments, the first lens may have a negative optical power, with its image-side surface being concave; the second lens may have a positive optical power; the third lens can have positive focal power, and the object side surface of the third lens is a convex surface; the fourth lens can have negative focal power, and the object side surface of the fourth lens is a convex surface, and the image side surface of the fourth lens is a concave surface; the fifth lens can have positive focal power, and the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a convex surface; the sixth lens element has negative focal power, and has a convex object-side surface and a concave image-side surface; the seventh lens element may have a positive or negative power, and the image-side surface thereof is concave.

In some embodiments, the maximum field angle FOV of the optical lens satisfies: the FOV is more than or equal to 120 degrees. The wide-view-angle characteristic of the optical lens is favorably realized, the aperture of the lens is favorably increased, and the imaging effect of the optical lens in a dark environment is improved.

In some embodiments, the aperture value FNO of the optical lens satisfies: FNO is more than 2.25 and less than 2.4. The large aperture configuration enables the optical lens to obtain sufficient image information even in the case of insufficient external light source (such as night) or short exposure time (such as dynamic photography), and contributes to speeding up the image capturing and obtaining good image quality.

In some embodiments, a distance TTL from the object side surface of the first lens element to the imaging surface on the optical axis and a half ImgH of a diagonal length of the effective pixel area on the imaging surface of the optical lens satisfy: TTL/ImgH is more than 1.10 and less than 1.70. The optical lens is beneficial to providing a large visual angle and reducing the volume of the optical lens as much as possible.

In some embodiments, the total effective focal length f of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: f/EPD is more than or equal to 2.2 and less than or equal to 2.23. The optical lens obtains the characteristic of a large aperture under the condition of realizing the long-focus characteristic, more incident light rays can enter the optical lens, and the relative brightness of the optical lens is improved to obtain a clear and high-quality imaging effect.

In some embodiments, the radius of curvature R41 of the object-side surface of the fourth lens and the radius of curvature R42 of the image-side surface of the fourth lens satisfy: 3.5 < (R41+ R42)/(R41-R42) < 6.0. The shape of the fourth lens can be effectively controlled, so that the incident angle of imaging light at the fourth lens is in a desired range, and the optical lens is better matched with the imaging chip.

In some embodiments, the radius of curvature R51 of the object-side surface of the fifth lens and the radius of curvature R52 of the image-side surface of the fifth lens satisfy: 2.0 < (R51+ R52)/(R51-R52) < 3.0. The shape of the fifth lens can be effectively controlled, so that the surface shape of the fifth lens is not too gentle or excessively bent, the aberration of the optical system can be corrected by the fifth lens, and the imaging quality of the optical system is improved.

In some embodiments, the radius of curvature R61 of the object-side surface of the sixth lens and the radius of curvature R62 of the image-side surface of the sixth lens satisfy: 2.0 < (R61+ R62)/(R61-R62) < 35.0. The shape of the sixth lens can be effectively controlled, so that the shape of the sixth lens cannot be excessively bent, the aberration correction capability of the optical lens on the edge field of view is favorably improved, the height of an imaging surface of the optical lens is favorably improved, the imaging range of an optical system is expanded, and the processing manufacturability of the lens is improved.

In some embodiments, the effective focal length f1 of the first lens and the total effective focal length f of the optical lens satisfy: -2.0 < f1/f < -1.3. The proportion relation of the effective focal length of the first lens in the total effective focal length of the optical lens is reasonably distributed, so that the deflection of light rays in the first lens can be reduced, the overlarge focal power of the first lens is avoided, the sensitivity of the first lens is reduced, the overlarge tolerance requirement is avoided, the spherical aberration, astigmatism and the like generated by the first lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f3 of the third lens and the total effective focal length f of the optical lens satisfy: f3/f is more than 0.8 and less than 1.6. The proportional relation between the effective focal length of the third lens and the total effective focal length of the optical lens is reasonably set, so that the aberration correction capability of the optical imaging lens is favorably improved, the third lens is matched with other lenses to better correct the system aberration, the size of the optical lens is favorably controlled, and the miniaturization requirement is met.

In some embodiments, the effective focal length f4 of the fourth lens and the total effective focal length f of the optical lens satisfy: -4.1 < f4/f < -1.2. The proportional relation between the effective focal length of the fourth lens and the total effective focal length of the optical lens is reasonably set, so that the overlarge focal power of the fourth lens can be avoided, the sensitivity of the optical lens is low, the imaging quality is good, the size of the optical lens can be favorably controlled, and the miniaturization requirement can be met.

In some embodiments, the effective focal length f5 of the fifth lens and the total effective focal length f of the optical lens satisfy: f5/f is more than 0.9 and less than 1.9. The proportional relation between the effective focal length of the fifth lens and the total effective focal length of the optical lens is reasonably set, so that the light angle of the optical lens is gentle, the tolerance sensitivity is reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the air space CT12 between the first lens and the second lens on the optical axis and the distance TTL between the object side surface of the first lens and the image plane on the optical axis satisfy: 0.09 < CT12/TTL < 0.18. The air space of the first lens and the second lens on the optical axis is reasonably arranged, so that light can be smoothly transited, the spherical aberration of the lens can be corrected, and the tolerance sensitivity of the first lens and the second lens can be reduced.

In some embodiments, the air space CT23 between the second lens and the third lens on the optical axis and the distance TTL between the object side surface of the first lens and the image plane on the optical axis satisfy: CT23/TTL is more than 0.01 and less than 0.04. The air space of the second lens and the third lens on the optical axis is reasonably arranged, so that the light distribution can be adjusted, the improvement of the resolution of the optical lens is facilitated, and the compactness and the miniaturization of the optical lens structure are realized.

In some embodiments, the air space CT45 between the fourth lens and the fifth lens on the optical axis and the distance TTL between the object-side surface of the first lens and the image plane on the optical axis satisfy: 0.08 < CT45/TTL < 0.14. The air space between the fourth lens and the fifth lens on the optical axis is reasonably arranged, so that light can be smoothly transited, the spherical aberration of the lens can be corrected, and the tolerance sensitivity of the fourth lens and the fifth lens can be reduced.

In some embodiments, the maximum effective radius DM72 of the image side surface of the seventh lens and the total effective focal length f of the optical lens satisfy: DM72/f is more than 2.4 and less than 3.0. The size configuration of the seventh lens is favorably adapted to the size of the imaging chip.

In some embodiments, the maximum effective radius DM11 of the object-side surface of the first lens and the maximum effective radius DM72 of the image-side surface of the seventh lens satisfy: 2.1 < DM11/DM72 < 2.7. The optical effective areas of the object side end and the image side end of the optical lens are reasonably controlled, and the miniaturization of the optical lens with a large aperture configuration is facilitated.

In some embodiments, the central thickness CT3 of the third lens and the distance TTL on the optical axis from the object side surface to the image plane of the first lens satisfy: 0.10 < CT3/TTL < 0.12. The design of miniaturization of the optical lens and thinning of the lens can be realized, aberration and distortion can be corrected favorably, the light transmission quantity can be maintained, and the improvement of relative illumination is facilitated.

In some embodiments, the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element are all plastic aspheric lens elements. Each lens adopts an aspheric lens, so that the structure of the lens is more compact, and the imaging quality is better.

The use of aspheric lenses has at least three advantages:

1. the lens has better imaging quality;

2. the structure of the lens is more compact;

3. the total optical length of the lens is shorter.

The profile z of each aspheric lens in various embodiments of the present invention can be defined using, but not limited to, the following aspheric equation:

，

wherein z is the distance rise from the aspheric surface vertex when the aspheric surface is at the position with the height h along the optical axis direction, c is the paraxial curvature of the aspheric surface, c =1/R (namely the paraxial curvature c is the reciprocal of the curvature radius R), k is the cone coefficient, A_2iIs a 2 i-th order correction coefficient of the aspheric surface.

In the following embodiments, the thickness, the curvature radius, and the material selection of each lens in the optical lens are different, and specific differences can be referred to in the parameter tables of the embodiments.

First embodiment

An optical lens according to a first embodiment of the present application is described below with reference to fig. 1 to 5. Fig. 1 shows a schematic structural diagram of an optical lens according to a first embodiment 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 stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and an image forming surface S17.

The first lens element L1 has negative power, and has a convex object-side surface S1 and a concave image-side surface S2;

the second lens L2 has positive power, and has a concave object-side surface S3 and a convex image-side surface S4;

the third lens element L3 has positive power, and has a convex object-side surface S5 and a convex image-side surface S6;

the fourth lens element L4 has negative power, and has a convex object-side surface S7 and a concave image-side surface S8;

the fifth lens element L5 has positive power, and has a concave object-side surface S9 and a convex image-side surface S10;

the sixth lens element L6 has negative power, and has a convex object-side surface S11 and a concave image-side surface S12;

the seventh lens element L7 has positive power, and has a convex object-side surface S13 and a concave image-side surface S14.

In the first embodiment, the total effective focal length f =2.98mm, the distance TTL on the optical axis from the object-side surface S1 of the first lens to the imaging plane S17 is 8.69mm, the half ImgH of the diagonal line length of the effective pixel area on the imaging plane S17 is 5.16mm, the maximum half field angle Semi-FOV of the optical lens is 60 °, and the f-number FNO of the optical lens is 2.36.

Table 1 shows a basic parameter table of the optical lens of the first embodiment, in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm).

TABLE 1

In the first embodiment, the object side and the image side of any one of the first lens L1 to the seventh lens L7The surfaces are aspheric surfaces. Table 2 below shows the high-order term coefficients A that can be used for the aspherical mirror surfaces S1 through S14 in the first embodiment₄、A₆、A₈、A₁₀、A₁₂、A₁₄And A₁₆。

TABLE 2

Fig. 2 shows a field curvature curve of the first embodiment, which represents the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, the horizontal axis represents an offset amount (unit: mm), and the vertical axis represents a half field angle (unit: °). As can be seen from FIG. 2, the field curvature of the meridional image plane and the sagittal image plane is controlled within + -0.3 mm, which indicates that the field curvature of the optical lens is better corrected.

Fig. 3 shows distortion curves of the first embodiment, which represent f-tan θ distortions of light rays of different wavelengths at different image heights on the image forming surface, with the horizontal axis representing f-tan θ distortion (unit:%) and the vertical axis representing half field angle (unit:%). As can be seen from fig. 3, the optical distortion at different image heights on the image plane is controlled within ± 3%, which indicates that the distortion of the optical lens is well corrected.

Fig. 4 shows an axial aberration curve of the first embodiment, which represents the aberration on the optical axis at the imaging plane, with the horizontal axis representing the axial chromatic aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from fig. 4, the offset of the axial chromatic aberration is controlled within ± 0.04mm, which indicates that the optical lens can effectively correct the axial chromatic aberration.

Fig. 5 shows a vertical axis chromatic aberration curve of the first embodiment, which represents chromatic aberration at different image heights on the image formation plane for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis represents the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis represents the normalized angle of view. As can be seen from FIG. 5, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength are controlled within + -5 μm, which shows that the optical lens can effectively correct the aberration of the fringe field and the secondary spectrum of the whole image plane.

As can be seen from fig. 2 to 5, the optical lens of the first embodiment can achieve good imaging quality.

Second embodiment

An optical lens according to a second embodiment of the present application is described below with reference to fig. 6 to 10. Fig. 6 shows a schematic structural diagram of an optical lens according to a second embodiment of the present application.

As shown in fig. 6, 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 stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and an image forming surface S17.

the seventh lens L7 has negative power, and has a concave object-side surface S13 and a concave image-side surface S14.

In the second embodiment, the total effective focal length f =3.27mm, the distance TTL on the optical axis from the object-side surface S1 of the first lens to the imaging plane S17 is 7.23mm, the half ImgH of the diagonal line length of the effective pixel area on the imaging plane S17 is 6.14mm, the maximum half field angle Semi-FOV of the optical lens is 62 °, and the f-number FNO of the optical lens is 2.29.

Table 3 shows a basic parameter table of the optical lens of the second embodiment, in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm).

TABLE 3

In the second embodiment, both the object-side surface and the image-side surface of any one of the first lens L1 through the seventh lens L7 are aspheric. Table 4 below shows the high-order term coefficients A that can be used for the aspherical mirror surfaces S1 through S14 in the second embodiment₄、A₆、A₈、A₁₀、A₁₂、A₁₄And A₁₆。

Table 4 shows aspherical parameters of respective lenses in the optical lens of the second embodiment.

TABLE 4

Fig. 7 shows a field curvature curve of the second embodiment, which represents the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of displacement (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from fig. 7, the field curvature of the meridional image plane and the sagittal image plane is controlled within ± 1mm, which indicates that the field curvature of the optical lens is better corrected.

Fig. 8 shows distortion curves of the second embodiment, which represent f-tan θ distortions of light rays of different wavelengths at different image heights on the image forming surface, with the horizontal axis representing f-tan θ distortion (unit:%) and the vertical axis representing half field angle (unit:%). As can be seen from fig. 8, the optical distortion at different image heights on the image plane is controlled within ± 15%, which indicates that the distortion of the optical lens is well corrected.

Fig. 9 shows an axial aberration curve of the second embodiment, which represents the aberration on the optical axis at the imaging plane, with the horizontal axis representing the axial chromatic aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from fig. 9, the offset of the axial chromatic aberration is controlled within ± 0.2mm, which indicates that the optical lens can effectively correct the axial chromatic aberration.

Fig. 10 shows a vertical axis chromatic aberration curve of the second embodiment, which represents chromatic aberration at different image heights on the image formation plane for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis represents the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis represents the normalized angle of view. As can be seen from fig. 10, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ± 15 μm, which indicates that the optical lens can effectively correct the aberration of the fringe field and the secondary spectrum of the entire image plane.

As can be seen from fig. 7 to 10, the optical lens according to the second embodiment can achieve good imaging quality.

Third embodiment

An optical lens according to a third embodiment of the present application is described below with reference to fig. 11 to 15. Fig. 11 shows a schematic structural diagram of an optical lens according to a third embodiment of the present application.

As shown in fig. 11, 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 stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and an image forming surface S17.

the second lens L2 has positive power, and has a convex object-side surface S3 and a concave image-side surface S4;

In the third embodiment, the total effective focal length f =2.97mm of the optical lens, the distance TTL on the optical axis from the object-side surface S1 of the first lens to the imaging plane S17 is 7.19mm, the half ImgH of the diagonal line length of the effective pixel area on the imaging plane S17 is 5.14mm, the maximum half field angle Semi-FOV of the optical lens is 60 °, and the f-number FNO of the optical lens is 2.31.

Table 5 shows a basic parameter table of the optical lens of the third embodiment, in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm).

TABLE 5

In the third embodiment, both the object-side surface and the image-side surface of any one of the first lens L1 through the seventh lens L7 are aspheric. Table 6 below shows the high-order term coefficients A that can be used for the aspherical mirror surfaces S1 through S14 in the third embodiment₄、A₆、A₈、A₁₀、A₁₂、A₁₄、A₁₆、A₁₈、A₂₀。

TABLE 6

Fig. 12 shows a field curvature curve of the third embodiment, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of displacement (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from fig. 12, the field curvature of the meridional image plane and the sagittal image plane is controlled within ± 0.1mm, which indicates that the field curvature of the optical lens is better corrected.

Fig. 13 shows distortion curves of the third embodiment, which represent f-tan θ distortions of light rays of different wavelengths at different image heights on the image forming surface, with the horizontal axis representing the f-tan θ distortions and the vertical axis representing the half field angle (unit: °). As can be seen from fig. 13, the optical distortion at different image heights on the image plane is controlled within ± 15%, indicating that the distortion of the optical lens is well corrected.

Fig. 14 shows an axial aberration curve of the third embodiment, which represents the aberration on the optical axis at the imaging plane, with the horizontal axis representing the axial chromatic aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from fig. 14, the offset of the axial chromatic aberration is controlled within ± 0.05mm, which indicates that the optical lens can effectively correct the axial chromatic aberration.

Fig. 15 shows a vertical axis chromatic aberration curve of the third embodiment, which represents chromatic aberration at different image heights on the image forming surface for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis represents the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis represents the normalized angle of view. As can be seen from fig. 15, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ± 4 μm, which indicates that the optical lens can effectively correct the aberration of the fringe field and the secondary spectrum of the entire image plane.

Fourth embodiment

An optical lens according to a fourth embodiment of the present application is described below with reference to fig. 16 to 20. Fig. 16 shows a schematic structural diagram of an optical lens according to a fourth embodiment of the present application.

As shown in fig. 16, 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 stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and an image forming surface S17.

the seventh lens element L7 has negative power, and has a convex object-side surface S13 and a concave image-side surface S14.

In the fourth embodiment, the total effective focal length f =3.05mm, the distance TTL on the optical axis from the object-side surface S1 of the first lens to the imaging plane S17 is 7.16mm, the half ImgH of the diagonal line length of the effective pixel area on the imaging plane S17 is 5.74mm, the maximum half field angle Semi-FOV of the optical lens is 62 °, and the f-number FNO of the optical lens is 2.32.

Table 7 shows a basic parameter table of the optical lens of the fourth embodiment, in which the units of the radius of curvature, the thickness, and the focal length are all millimeters (mm).

TABLE 7

In the fourth embodiment, both the object-side surface and the image-side surface of any one of the first lens L1 through the seventh lens L7 are aspheric. Table 8 below shows the high-order term coefficients A that can be used for the aspherical mirror surfaces S1 through S14 in the fourth embodiment₄、A₆、A₈、A₁₀、A₁₂、A₁₄、A₁₆、A₁₈、A₂₀。

TABLE 8

Fig. 17 shows a field curvature curve of the fourth embodiment, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of displacement (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from fig. 17, the field curvature of the meridional image plane and the sagittal image plane is controlled within ± 2mm, which indicates that the field curvature of the optical lens is better corrected.

Fig. 18 shows a distortion curve of the fourth embodiment, which shows f-tan θ distortion of light rays of different wavelengths at different image heights on the image forming surface, with the horizontal axis showing f-tan θ distortion and the vertical axis showing half field angle (unit: °). As can be seen from fig. 18, the optical distortion at different image heights on the image plane is controlled within ± 10%, indicating that the distortion of the optical lens is well corrected.

Fig. 19 shows an axial aberration curve of the fourth embodiment, which represents the aberration on the optical axis at the imaging plane, with the horizontal axis representing the axial chromatic aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from fig. 19, the offset of the axial chromatic aberration is controlled within ± 0.06mm, which indicates that the optical lens can effectively correct the axial chromatic aberration.

Fig. 20 shows a vertical axis chromatic aberration curve of the fourth embodiment, which represents chromatic aberration at different image heights on the image forming plane for each wavelength with respect to the center wavelength (0.55 μm), the horizontal axis represents the vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis represents the normalized angle of view. As can be seen from fig. 20, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ± 20 μm, which indicates that the optical lens can effectively correct the aberration of the fringe field and the secondary spectrum of the entire image plane.

As can be seen from fig. 17 to 20, the optical lens according to the fourth embodiment can achieve good imaging quality.

In summary, the first to fourth embodiments satisfy the relational expressions shown in table 9, respectively.

TABLE 9

In summary, the optical lens provided by the embodiment of the invention effectively reduces the size of the whole optical lens by reasonably matching the lens shape and the focal power combination among the lenses, realizes the effect of clear imaging of the large aperture while realizing miniaturization, has the advantages of miniaturization, high aperture and high imaging quality, has good applicability to portable electronic equipment, and can effectively improve the shooting experience of users.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. An optical lens, comprising, in order from an object side to an image side along an optical axis:

the image side surface of the first lens is a concave surface;

a second lens having a positive optical power;

a diaphragm;

wherein a maximum field angle FOV of the optical lens satisfies:

FOV≥120°；

1.10＜TTL/ImgH＜1.70；

2. An optical lens as claimed in claim 1, characterized in that the radius of curvature R41 of the object-side surface of the fourth lens and the radius of curvature R42 of the image-side surface of the fourth lens satisfy: 3.5 < (R41+ R42)/(R41-R42) < 6.0.

3. An optical lens according to claim 1, characterized in that the effective focal length f1 of the first lens and the total effective focal length f of the optical lens satisfy: -2.0 < f1/f < -1.3.

4. An optical lens according to claim 1, characterized in that the effective focal length f3 of the third lens and the total effective focal length f of the optical lens satisfy: f3/f is more than 0.8 and less than 1.6.

5. An optical lens according to claim 1, characterized in that the maximum effective radius DM72 of the seventh lens image side surface and the total effective focal length f of the optical lens satisfy: DM72/f is more than 2.4 and less than 3.0.

6. An optical lens as claimed in claim 1, characterized in that the maximum effective radius DM11 of the object-side surface of the first lens and the maximum effective radius DM72 of the image-side surface of the seventh lens satisfy: 2.1 < DM11/DM72 < 2.7.

7. An optical lens barrel according to claim 1, wherein the central thickness CT3 of the third lens element and the distance TTL on the optical axis from the object side surface to the image plane of the first lens element satisfy: 0.10 < CT3/TTL < 0.12.

8. An optical lens unit according to claim 1, wherein an air space CT12 between the first and second lenses on the optical axis and a distance TTL between an object side surface of the first lens and an image plane on the optical axis satisfy: 0.09 < CT12/TTL < 0.18.

9. An optical lens unit according to claim 1, wherein an air space CT45 between the fourth lens element and the fifth lens element on the optical axis and a distance TTL between an object side surface of the first lens element and an image plane on the optical axis satisfy: 0.08 < CT45/TTL < 0.14.