CN114296224A

CN114296224A - Optical lens

Info

Publication number: CN114296224A
Application number: CN202210221267.8A
Authority: CN
Inventors: 王义龙; 徐宇轩
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2022-03-09
Filing date: 2022-03-09
Publication date: 2022-04-08
Anticipated expiration: 2042-03-09
Also published as: CN114296224B

Abstract

The invention provides an optical lens, which comprises seven lenses in total, and sequentially comprises the following components from an object side to an imaging surface along an optical axis: a diaphragm; the first lens with positive focal power has a convex object-side surface and a concave image-side surface; the image side surface of the second lens is a concave surface; a third lens with 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 concave surface; the image side surface of the fourth lens is a convex surface; a fifth lens element with a focal power, wherein the object-side surface of the fifth lens element is convex and the image-side surface of the fifth lens element is concave; the image side surface of the sixth lens is a convex surface; a seventh lens having a negative refractive power, an object side surface of which is concave; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy the following conditions: TTL/IH is more than 0.5 and less than 0.6. The optical lens has the advantages of good imaging effect, large image plane and small distortion.

Description

Optical lens

Technical Field

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

Background

With the rapid improvement of the living standard of people and the rapid development of scientific technology, the imaging quality requirements of people on portable electronic products are higher and higher. Generally, the optical lens can obtain higher imaging quality by increasing the number of lenses of the optical lens or configuring parameters such as refractive power and surface shape of the lenses of the optical lens.

However, the optical lens has poor imaging quality due to the overlarge size and large aberration of the diffuse spot; in addition, in a severe environment, due to insufficient luminous flux, the optical lens has a small image plane, which limits the optical lens to be matched with an image sensor with higher pixels, and thus a shot image with high imaging quality cannot be obtained.

Therefore, how to make an optical system applied to a portable electronic product have optical characteristics of a large image plane and a small distortion while improving the imaging quality is a problem to be solved at present.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an optical lens having excellent imaging effect and simultaneously having advantages of large image plane and small distortion.

In order to achieve the purpose, the technical scheme of the invention is as follows:

the invention provides an optical lens, which comprises seven lenses in total, and sequentially comprises the following components from an object side to an imaging surface along an optical axis: a diaphragm; the first lens with positive focal power has a convex object-side surface and a concave image-side surface; the image side surface of the second lens is a concave surface; a third lens with 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 concave surface; the image side surface of the fourth lens is a convex surface; a fifth lens element with a focal power, wherein the object-side surface of the fifth lens element is convex and the image-side surface of the fifth lens element is concave; the image side surface of the sixth lens is a convex surface; a seventh lens having a negative refractive power, an object side surface of which is concave; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy the following conditions: TTL/IH is more than 0.5 and less than 0.6.

Preferably, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: f/IH is more than 0.45 and less than 0.6.

Preferably, the entrance pupil diameter EPD of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 0.22 < EPD/IH < 0.3.

Preferably, the real image height IH corresponding to the maximum field angle of the optical lens satisfies the effective focal length f and the field angle FOV:

。

preferably, the focal length f1 of the first lens and the focal length f7 of the seventh lens satisfy: f1/f7 is more than-1.6 and less than or equal to-0.8.

Preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens, the object side curvature radius R1 and the image side curvature radius R2 of the first lens satisfy: f1/f is more than or equal to 0.7 and less than 0.95, and R1/R2 is less than 0.5.

Preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens, the object-side curvature radius R5 and the image-side curvature radius R6 of the third lens satisfy: 2 < | f3/f | < 340; 7 < (R5+ R6)/(R5-R6) < 110.

Preferably, the effective focal length f of the optical lens, the focal length f5 of the fifth lens, and the object-side curvature radius R9 and the image-side curvature radius R10 of the fifth lens satisfy: 5 < | f5/f | < 120; -140 < (R9+ R10)/(R9-R10) < 40.

Preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens, the object-side curvature radius R11 and the image-side curvature radius R12 of the sixth lens satisfy: f6/f < 25 is more than 1.2; i R11/R12I < 1.5.

Preferably, the effective focal length f of the optical lens, the focal length f7 of the seventh lens, the object-side curvature radius R13 and the image-side curvature radius R14 of the seventh lens satisfy: -0.5 < f7/f < -1; i R13/R14I < 0.4.

Compared with the prior art, the invention has the beneficial effects that: the optical lens disclosed by the application combines the lens shape and the focal power between the lenses through reasonable collocation, and has the advantages of good imaging effect, large image plane and small distortion.

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 embodiment 1 of the present invention;

fig. 2 is a field curvature graph of the optical lens in embodiment 1 of the present invention;

FIG. 3 is a graph showing F-Tan (theta) distortion curves of an optical lens in embodiment 1 of the present invention;

fig. 4 is a graph showing axial aberration of the optical lens in embodiment 1 of the present invention;

FIG. 5 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 1 of the present invention;

fig. 6 is a schematic structural diagram of an optical lens system according to embodiment 2 of the present invention;

FIG. 7 is a graph of curvature of field of an optical lens in embodiment 2 of the present invention;

FIG. 8 is a graph showing F-Tan (theta) distortion curves of an optical lens in embodiment 2 of the present invention;

FIG. 9 is a graph showing axial aberrations of an optical lens system according to embodiment 2 of the present invention;

FIG. 10 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 2 of the present invention;

fig. 11 is a schematic structural diagram of an optical lens system according to embodiment 3 of the present invention;

FIG. 12 is a graph showing curvature of field of an optical lens in embodiment 3 of the present invention;

FIG. 13 is a graph showing F-Tan (theta) distortion curves of an optical lens in embodiment 3 of the present invention;

FIG. 14 is a graph showing axial aberrations of an optical lens according to embodiment 3 of the present invention;

FIG. 15 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 3 of the present invention;

fig. 16 is a schematic structural diagram of an optical lens system according to embodiment 4 of the present invention;

FIG. 17 is a graph of curvature of field of an optical lens in embodiment 4 of the present invention;

FIG. 18 is a graph showing F-Tan (theta) distortion curves of an optical lens in embodiment 4 of the present invention;

FIG. 19 is a graph showing axial aberrations of an optical lens system according to embodiment 4 of the present invention;

fig. 20 is a vertical axis chromatic aberration diagram of the optical lens in embodiment 4 of the present invention.

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 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.

An optical lens according to an embodiment of the present application includes, in order from an object side to an image side: the lens comprises a diaphragm, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens.

In some embodiments, the first lens has a positive optical power and the first lens has a convex-concave type. The first lens adopts the focal power, so that the capability of the optical lens for converging main light rays can be improved, and the volume of the optical lens can be compressed. The first lens is arranged in a surface mode, so that the large-view-angle light rays from the off-axis view field can be received favorably, the incident angle of the light rays entering the object side surface of the first lens is reduced, and total reflection is avoided.

In some embodiments, the second lens has a negative optical power and the second lens has a convex-concave or biconcave type. The second lens adopts the focal power, which is beneficial to balancing the aberration such as spherical aberration, astigmatism and the like generated by the second lens.

In some embodiments, the third lens has a positive or negative power and the third lens has a convex-concave type. The third lens adopts the surface type arrangement, can adjust the advancing direction of light rays, maintains the short total length of the optical lens and is beneficial to increasing the area of an imaging surface.

In some embodiments, the fourth lens has a positive optical power and the fourth lens has a biconvex or meniscus shape. The fourth lens adopts the focal power, so that the positive focal power required by the compression volume can be distributed, and the reduction of the sensitivity of the fourth lens is facilitated.

In some embodiments, the fifth lens has a positive or negative power and the fifth lens has a convex-concave type. The fifth lens adopts the surface type, so that the object side surface of the fifth lens has enough light converging capability, and the situation that the miniaturization of the optical lens is not facilitated due to excessive light divergence is avoided.

In some embodiments, the sixth lens has a positive optical power and the sixth lens has a biconvex or meniscus shape. The sixth lens adopts the focal power, which is beneficial to enhancing the light path convergence capability of the image side end of the optical lens, and enables the optical lens to have sufficient symmetry so as to improve the imaging quality.

In some embodiments, the seventh lens has a negative optical power and the seventh lens has a biconcave or meniscus shape. The seventh lens adopts the focal power, which is beneficial to balancing the focal power configuration at the image side end of the optical lens and ensuring that the optical lens has enough symmetry to reduce the generation of aberration.

In some embodiments, the first lens is preceded by a stop for limiting the light beam. When the diaphragm is arranged in front of the first lens, stray light can be reduced, and total reflection is avoided.

In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: TTL/IH is more than 0.5 and less than 0.6. Satisfying the above range is advantageous for miniaturization of the optical lens, and makes the total length thereof compressed and the image plane enlarged balanced.

In some embodiments, the real image height IH at which the effective focal length f of the optical lens corresponds to the maximum field angle satisfies: f/IH is more than 0.45 and less than 0.6. The range is satisfied, the imaging area of the optical lens is increased, and the size of the optical lens, the visual angle and the size of the imaging surface are balanced.

In some embodiments, the real image height IH of the optical lens corresponding to the maximum field angle and the entrance pupil diameter EPD satisfy: 0.22 < EPD/IH < 0.3. Satisfying above-mentioned scope, being favorable to obtaining suitable light flux for optical lens's entrance pupil diameter and imaging surface size phase-match have guaranteed the definition of shooing the image.

In some embodiments, the real image height IH corresponding to the maximum field angle of the optical lens satisfies the effective focal length f and the field angle FOV:

the optical lens meets the range, is favorable for reducing the distortion of the optical lens, has a larger field angle and better imaging quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens, the object side radius of curvature R1 of the first lens, and the image side radius of curvature R2 of the first lens satisfy: f1/f is more than or equal to 0.7 and less than 0.95, and R1/R2 is less than 0.5. The optical lens meets the range, can enable the first lens to have proper positive focal power, is beneficial to improving the capability of the optical lens for converging main light rays, and reduces aberration generated by the first lens as much as possible.

In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens, the object-side radius of curvature R3 of the second lens, and the image-side radius of curvature R4 of the second lens satisfy: -4 < f2/f < -1, | R3/R4| < 28. Satisfying the above range allows the second lens to have a suitable negative power, which is advantageous for balancing aberrations such as spherical aberration and astigmatism generated by the second lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens, the object-side radius of curvature R5 of the third lens, and the image-side radius of curvature R6 of the third lens satisfy: 2 < | f3/f | < 340; 7 < (R5+ R6)/(R5-R6) < 110. Satisfying the above range, the third lens can have a wide range of power selection, which is advantageous for balancing aberrations of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens, the object side curvature radius R7 and the image side curvature radius R8 of the fourth lens satisfy: 4 < f4/f < 25, | R7/R8| < 22. Satisfying the above range, the fourth lens can have a proper positive focal power, which is beneficial to reducing the sensitivity of the first lens, and can balance the spherical aberration, the coma aberration and the astigmatism generated by the fourth lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens, the object-side radius of curvature R9 of the fifth lens, and the image-side radius of curvature R10 of the fifth lens satisfy: 5 < | f5/f | < 120, -140 < (R9+ R10)/(R9-R10) < 40. Satisfying the above range, the fifth lens can have a large range of focal power, which is advantageous for balancing aberrations of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens, the object-side radius of curvature R11 of the sixth lens, and the image-side radius of curvature R12 of the sixth lens satisfy: 1.2 < f6/f < 25, | R11/R12| < 1.5. Satisfying the above range, the sixth lens element can have a proper positive refractive power, which is advantageous for balancing astigmatism of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens, the object side curvature radius R13 and the image side curvature radius R14 of the seventh lens satisfy: -0.5 < f7/f < -1, | R13/R14| < 0.4. Satisfying the above range, the seventh lens can have an appropriate negative refractive power, which is advantageous for balancing the curvature of field of the optical lens.

In some embodiments, the focal length f1 of the first lens and the focal length f7 of the seventh lens satisfy: f1/f7 is more than-1.6 and less than or equal to-0.8. The optical power of the first lens and the optical power of the seventh lens can be reasonably distributed, and the field curvature of the optical lens can be corrected.

In order to make the system have better optical performance, a plurality of aspheric lenses are adopted in the lens, and the surface shapes of the aspheric surfaces of the optical lens satisfy the following equation:

；

wherein z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance between the optical axis and the curved surface, c is the curvature of the vertex of the curved surface, K is the coefficient of the quadric surface, and A, B, C, D, E, F, G, H are the coefficients of the second-order, fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order curved surfaces, respectively.

The invention is further illustrated below in the following examples. In various embodiments, the thickness, the curvature radius, and the material selection of each lens in the optical lens are different, and the specific differences can be referred to in the parameter tables of the various embodiments. The following examples are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following examples, and any other changes, substitutions, combinations or simplifications which do not depart from the innovative points of the present invention should be construed as being equivalent substitutions and shall be included within the scope of the present invention.

Example 1

Referring to fig. 1, a schematic structural diagram of an optical lens system according to embodiment 1 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: the lens comprises a diaphragm, 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 a filter G1.

A diaphragm;

the first lens element L1 has positive power, and has a convex object-side surface S2 and a concave image-side surface S3;

the second lens element L2 has negative power, and has a convex object-side surface S4 and a concave image-side surface S5;

the third lens element L3 has positive power, and has a convex object-side surface S6 and a concave image-side surface S7;

the fourth lens L4 has positive power, and both the object-side surface S8 and the image-side surface S9 are convex;

the fifth lens element L5 has negative power, and has a convex object-side surface S10 and a concave image-side surface S11;

the sixth lens element L6 has positive power, and has a concave object-side surface S12 and a convex image-side surface S13;

the seventh lens L7 has a negative optical focal length, and both the object side surface S14 and the image side surface S15 are concave.

The relevant parameters of each lens in the optical lens in example 1 are shown in table 1-1.

TABLE 1-1

The surface shape parameters of the aspherical lens of the optical lens in example 1 are shown in table 1-2.

Tables 1 to 2

In the present embodiment, a field curvature graph, an F-tan (theta) distortion graph, an axial aberration graph, and a vertical axis chromatic aberration graph of the optical lens are respectively shown in fig. 2, fig. 3, fig. 4, and fig. 5.

Fig. 2 shows a field curvature curve of example 1, 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 the figure, 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 F-Tan (theta) distortion curves of example 1, in which F-Tan (theta) distortion of a light ray of a center wavelength at different image heights on an image forming plane is shown, the horizontal axis shows F-Tan (theta) distortion (unit:%), and the vertical axis shows a half field angle (unit:%). As can be seen from the figure, the F-Tan (theta) distortion of the optical lens is controlled within +/-2% at the maximum half field angle, which indicates that the F-Tan (theta) distortion of the optical lens is better corrected.

Fig. 4 shows an axial aberration curve of example 1, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ± 0.1mm, which indicates that the optical lens can effectively correct the axial aberration.

Fig. 5 shows a vertical axis chromatic aberration curve of example 1, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.555 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-6 mu m, which shows that the optical lens can effectively correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image plane.

Example 2

Referring to fig. 6, a schematic structural diagram of an optical lens system according to embodiment 2 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: the lens comprises a diaphragm, 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 a filter G1.

A diaphragm;

the second lens L2 has negative power, and both the object-side surface S4 and the image-side surface S5 are concave;

the third lens element L3 has negative power, and has a convex object-side surface S6 and a concave image-side surface S7;

the fourth lens element L4 has positive power, and has a concave object-side surface S8 and a convex image-side surface S9;

the fifth lens element L5 has positive power, and has a convex object-side surface S10 and a concave image-side surface S11;

the sixth lens L6 has positive power, and both the object-side surface S12 and the image-side surface S13 are convex;

the seventh lens element L7 has a negative focal length, a concave object-side surface S14 and a convex image-side surface S15.

The relevant parameters of each lens in the optical lens in embodiment 2 are shown in table 2-1.

TABLE 2-1

The surface shape parameters of the aspherical lens of the optical lens in example 2 are shown in table 2-2.

Tables 2 to 2

In the present embodiment, a field curvature graph, an F-tan (theta) distortion graph, an axial aberration graph, and a vertical axis chromatic aberration graph of the optical lens are respectively shown in fig. 7, fig. 8, fig. 9, and fig. 10.

Fig. 7 shows a field curvature curve of example 2, 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 the figure, the field curvature of the meridional image plane and the sagittal image plane is controlled within +/-0.7 mm, which indicates that the field curvature of the optical lens is better corrected.

FIG. 8 shows F-Tan (theta) distortion curves of example 2, in which F-Tan (theta) distortion of a light ray of a center wavelength at different image heights on an image forming plane is shown, the horizontal axis shows F-Tan (theta) distortion (unit:%), and the vertical axis shows a half field angle (unit:%). It can be seen from the figure that the F-tan (theta) distortion of the optical lens is controlled within ± 2.5% at the maximum half field angle, which indicates that the F-tan (theta) distortion of the optical lens is better corrected.

Fig. 9 shows an axial aberration curve of example 2, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ± 0.07mm, which indicates that the optical lens can effectively correct the axial aberration.

Fig. 10 shows a vertical axis chromatic aberration curve of example 2, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.555 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-6 mu m, which shows that the optical lens can effectively correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image plane.

Example 3

Referring to fig. 11, a schematic structural diagram of an optical lens system according to embodiment 3 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: the lens comprises a diaphragm, 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 a filter G1.

A diaphragm;

The relevant parameters of each lens in the optical lens in example 3 are shown in table 3-1.

TABLE 3-1

The surface shape parameters of the aspherical lens of the optical lens in example 3 are shown in table 3-2.

TABLE 3-2

In the present embodiment, a field curvature graph, an F-tan (theta) distortion graph, an axial aberration graph, and a vertical axis chromatic aberration graph of the optical lens are respectively shown in fig. 12, fig. 13, fig. 14, and fig. 15.

Fig. 12 shows a field curvature curve of example 3, 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 the figure, the field curvature of the meridional image plane and the sagittal image plane is controlled within +/-0.4 mm, which indicates that the field curvature of the optical lens is better corrected.

FIG. 13 shows F-Tan (theta) distortion curves of example 3, in which F-Tan (theta) distortion of a light ray of a center wavelength at different image heights on an image forming plane is shown, the abscissa shows F-Tan (theta) distortion (unit:%), and the ordinate shows a half field angle (unit:%). It can be seen from the figure that the F-tan (theta) distortion of the optical lens is controlled within ± 2.5% at the maximum half field angle, which indicates that the F-tan (theta) distortion of the optical lens is better corrected.

Fig. 14 shows an axial aberration curve of example 3, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ± 0.08mm, which indicates that the optical lens can effectively correct the axial aberration.

Fig. 15 shows a vertical axis chromatic aberration curve of example 3, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.555 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-7 mu m, which shows that the optical lens can effectively correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image plane.

Example 4

Referring to fig. 16, a schematic structural diagram of an optical lens system according to embodiment 4 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: the lens comprises a diaphragm, 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 a filter G1.

A diaphragm;

The relevant parameters of each lens in the optical lens in example 4 are shown in table 4-1.

TABLE 4-1

The surface shape parameters of the aspherical lens of the optical lens in example 4 are shown in table 4-2.

TABLE 4-2

In the present embodiment, a field curvature graph, an F-tan (theta) distortion graph, an axial aberration graph, and a vertical axis chromatic aberration graph of the optical lens are respectively shown in fig. 17, fig. 18, fig. 19, and fig. 10.

Fig. 17 shows a field curvature curve of example 4, 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 the figure, the field curvature of the meridional image plane and the sagittal image plane is controlled within +/-0.6 mm, which indicates that the field curvature of the optical lens is better corrected.

FIG. 18 shows F-Tan (theta) distortion curves of example 4, in which F-Tan (theta) distortion of a light ray of a center wavelength at different image heights on an image forming plane is shown, the horizontal axis shows F-Tan (theta) distortion (unit:%), and the vertical axis shows a half field angle (unit:%). As can be seen from the figure, the F-Tan (theta) distortion of the optical lens is controlled within +/-3% at the maximum half field angle, which indicates that the F-Tan (theta) distortion of the optical lens is better corrected.

Fig. 19 shows an axial aberration curve of example 4, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: mm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ± 0.05mm, which indicates that the optical lens can effectively correct the axial aberration.

Fig. 20 shows a vertical axis chromatic aberration curve of example 4, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.555 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-6 mu m, which shows that the optical lens can effectively correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image plane.

Please refer to table 5, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the f-number FNO, the real image height IH, and the field angle FOV of the optical lens, and the values corresponding to each conditional expression in the embodiments.

TABLE 5

In summary, the optical lens of the embodiment of the invention realizes the excellent imaging effect and has the advantages of both large image plane and small distortion by reasonably matching the combination of the lens shape and the focal power among the lenses.

The above examples are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the 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 invention should be subject to the appended claims.

Claims

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

a diaphragm;

the first lens with positive focal power has a convex object-side surface and a concave image-side surface;

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

a third lens with 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 concave surface;

the image side surface of the fourth lens is a convex surface;

a fifth lens element with a focal power, wherein the object-side surface of the fifth lens element is convex and the image-side surface of the fifth lens element is concave;

the image side surface of the sixth lens is a convex surface;

a seventh lens having a negative refractive power, an object side surface of which is concave;

the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy the following conditions: TTL/IH is more than 0.5 and less than 0.6.

2. The optical lens according to claim 1, wherein a real image height IH of the optical lens corresponding to an effective focal length f and a maximum field angle satisfies: f/IH is more than 0.45 and less than 0.6.

3. The optical lens of claim 1, wherein the entrance pupil diameter EPD of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 0.22 < EPD/IH < 0.3.

4. The optical lens according to claim 1, wherein the real image height IH corresponding to the maximum field angle of the optical lens satisfies the effective focal length f and the field angle FOV:

。

5. an optical lens according to claim 1, characterized in that the focal length f1 of the first lens and the focal length f7 of the seventh lens satisfy: f1/f7 is more than-1.6 and less than or equal to-0.8.

6. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f1 of the first lens, the object side curvature radius R1 and the image side curvature radius R2 of the first lens satisfy: f1/f is more than or equal to 0.7 and less than 0.95, and R1/R2 is less than 0.5.

7. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f3 of the third lens, the object side curvature radius R5 and the image side curvature radius R6 of the third lens satisfy: 2 < | f3/f | < 340; 7 < (R5+ R6)/(R5-R6) < 110.

8. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f5 of the fifth lens, the object side curvature radius R9 and the image side curvature radius R10 of the fifth lens respectively satisfy: 5 < | f5/f | < 120; -140 < (R9+ R10)/(R9-R10) < 40.

9. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f6 of the sixth lens, the object side curvature radius R11 and the image side curvature radius R12 of the sixth lens satisfy: f6/f < 25 is more than 1.2; i R11/R12I < 1.5.

10. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f7 of the seventh lens, the object side radius of curvature R13 and the image side radius of curvature R14 of the seventh lens satisfy: -0.5 < f7/f < -1; i R13/R14I < 0.4.