CN115291371B

CN115291371B - Optical lens

Info

Publication number: CN115291371B
Application number: CN202211186760.7A
Authority: CN
Inventors: 林炉营; 王昆; 魏文哲; 王克民
Original assignee: Jiangxi Lianchuang Electronic Co Ltd
Current assignee: Jiangxi Lianchuang Electronic Co Ltd
Priority date: 2022-09-28
Filing date: 2022-09-28
Publication date: 2023-02-28
Anticipated expiration: 2042-09-28
Also published as: CN115291371A

Abstract

The invention provides an optical lens, which comprises seven lenses in total, wherein the seven lenses are sequentially arranged from an object side to an imaging surface along an optical axis: a first lens having a negative optical power; a diaphragm; a second lens having a positive optical power; a third lens having positive optical power; a fourth lens having a negative optical power; a fifth lens having a negative optical power; a sixth lens having positive optical power; a seventh lens having a negative optical power; the real image height IH corresponding to the effective focal length f, the maximum field angle FOV and the maximum field angle of the optical lens meets the following requirements: 0.6 < (IH/2)/(fXtan (FOV/2)) < 0.7. The optical lens has the advantages of large field angle, large aperture, high definition and high imaging quality.

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 development of Advanced Driving Assistance Systems (ADAS), the vehicle-mounted lens has wider application and development. The method comprises a vehicle data recorder, automatic parking, front vehicle collision early warning (FCW), lane departure early warning (LDW), pedestrian detection early warning (PCW) and the like. Although the conventional wide-angle vehicle-mounted lens can basically meet the basic requirements of the use of a large-field vehicle-mounted lens, a plurality of defects still exist, such as too small field angle or aperture, insufficient resolution and the like.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an optical lens having advantages of large field angle, large aperture, high definition and high imaging quality.

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

an optical lens system comprises seven lenses, in order from an object side to an image plane along an optical axis:

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

a diaphragm;

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

a third lens having a positive refractive power, both the object-side surface and the image-side surface of the third lens being convex;

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

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

a sixth lens element having a positive refractive power, wherein both the object-side surface and the image-side surface are convex;

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

the real image height IH corresponding to the effective focal length f, the maximum field angle FOV and the maximum field angle of the optical lens meets the following requirements: 0.6 < (IH/2)/(f × tan (FOV/2)) < 0.7.

Preferably, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 4.5 and less than 5.0.

Preferably, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: IH/f is more than 1.6 and less than 1.9.

Preferably, the optical back focus BFL and the effective focal length f of the optical lens satisfy: 1.0 < BFL/f.

Preferably, the effective focal length f of the optical lens and the focal length f of the fifth lens element ₅ Satisfies the following conditions: -8.0 < f ₅ /f＜0。

Preferably, the effective focal length f of the optical lens and the focal length f of the seventh lens element ₇ Satisfies the following conditions: -10.0 < f ₇ /f＜0。

Preferably, the optical lens has an entrance pupil diameter EPD and an axial distance CT between the image side surface of the first lens and the object side surface of the second lens ₁₂ Satisfies the following conditions: 0.9 < CT ₁₂ /EPD＜1.7。

Preferably, the effective focal length f of the optical lens and the object-side curvature radius R of the second lens element ₃ Satisfies the following conditions: r is more than 1.4 ₃ /f＜1.9。

Preferably, the focal length f of the second lens ₂ And center thickness CT ₂ Satisfies the following conditions: f is more than 5.0 ₂ /CT ₂ ＜13。

Preferably, the total optical length TTL of the optical lens and the sum Σ CT of the central thicknesses of the first lens element to the seventh lens element along the optical axis satisfy: 0.4 <. Sigma CT/TTL < 0.7.

Compared with the prior art, the invention has the beneficial effects that: the optical lens disclosed by the application has the advantages of simultaneously having large field angle, large aperture, high definition and high imaging quality by reasonably matching the lens shapes and focal power combinations among the lenses.

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 θ distortion of an optical lens in example 1 of the present invention;

fig. 4 is a graph showing a relative illumination of an optical lens in embodiment 1 of the present invention;

fig. 5 is a MTF graph of an optical lens in embodiment 1 of the present invention;

FIG. 6 is a graph showing axial aberration curves of the optical lens system according to embodiment 1 of the present invention;

fig. 7 is a vertical axis chromatic aberration curve diagram of the optical lens in embodiment 1 of the present invention;

fig. 8 is a schematic structural diagram of an optical lens system according to embodiment 2 of the present invention;

fig. 9 is a graph of curvature of field of the optical lens in embodiment 2 of the present invention;

FIG. 10 is a graph showing F-tan θ distortion of an optical lens in example 2 of the present invention;

fig. 11 is a graph showing a relative illumination of an optical lens in embodiment 2 of the present invention;

fig. 12 is a MTF graph of an optical lens in embodiment 2 of the present invention;

FIG. 13 is a graph showing axial aberration curves of the optical lens system according to embodiment 2 of the present invention;

FIG. 14 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 2 of the present invention;

fig. 15 is a schematic structural view of an optical lens system according to embodiment 3 of the present invention;

fig. 16 is a graph of curvature of field of the optical lens in embodiment 3 of the present invention;

FIG. 17 is a graph showing F-tan θ distortion of an optical lens in embodiment 3 of the present invention;

fig. 18 is a graph showing a relative illuminance curve of the optical lens in embodiment 3 of the present invention;

fig. 19 is a MTF graph of an optical lens in embodiment 3 of the present invention;

FIG. 20 is a graph showing axial aberrations of an optical lens according to embodiment 3 of the present invention;

FIG. 21 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 3 of the present invention;

fig. 22 is a schematic structural diagram of an optical lens system according to embodiment 4 of the present invention;

FIG. 23 is a graph of curvature of field of an optical lens in embodiment 4 of the present invention;

FIG. 24 is a graph showing F-tan θ distortion of an optical lens in embodiment 4 of the present invention;

fig. 25 is a graph showing the relative illumination of the optical lens in embodiment 4 of the present invention;

fig. 26 is a MTF graph of an optical lens in embodiment 4 of the present invention;

FIG. 27 is a graph showing axial aberrations of an optical lens unit according to embodiment 4 of the present invention;

fig. 28 is a vertical axis chromatic aberration diagram of the optical lens system in embodiment 4 of the present invention;

fig. 29 is a schematic structural diagram of an optical lens system according to embodiment 5 of the present invention;

FIG. 30 is a graph showing curvature of field of the optical lens system according to embodiment 5 of the present invention;

FIG. 31 is a graph showing F-tan θ distortion of an optical lens in embodiment 5 of the present invention;

fig. 32 is a graph showing the relative illuminance of the optical lens in embodiment 5 of the present invention;

fig. 33 is a MTF graph of the optical lens in embodiment 5 of the present invention;

FIG. 34 is a graph showing axial aberrations of an optical lens in embodiment 5 of the present invention;

fig. 35 is a vertical axis chromatic aberration diagram of the optical lens in embodiment 5 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 only used 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 the list of listed features, that the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, the use of "may" mean "one or more embodiments of the application" when describing embodiments of the application. Also, the term "exemplary" is intended to refer to examples or illustrations.

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 optical lens according to the embodiment of the present invention includes, in order from an object side to an image side: the lens comprises a first lens, a diaphragm, 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 may have a negative power, which is beneficial for reducing the inclination angle of the incident light, thereby achieving effective sharing of a large field of view of the object. The image side surface of the first lens is a concave surface, so that the effective working caliber of the first lens can be reduced, and overlarge caliber of a lens behind the optical lens caused by excessive light divergence is avoided

In some embodiments, the second lens may have a positive focal power, which is beneficial to reduce the working aperture of the optical lens while converging light rays, thereby being beneficial to miniaturization of the optical lens. The second lens element has a convex object-side surface and a concave image-side surface, so that the energy of ghost images projected on an image plane due to reflection in the central area can be reduced, and the imaging quality of the optical lens can be improved.

In some embodiments, the third lens element may have positive refractive power, which is favorable for converging light rays and reducing the deflection angle of the light rays, so that the light rays are in smooth transition. The object side surface and the image side surface of the third lens are convex surfaces, and light rays with marginal field of view can be converged, so that the converged light rays can smoothly enter a rear-end optical system, and the imaging quality of the optical lens is improved.

In some embodiments, the fourth lens may have a negative power, and spherical aberration and chromatic aberration of the optical lens can be corrected by cooperating with the third lens. The object side surface of the fourth lens is a concave surface, the image side surface of the fourth lens is a convex surface, and the smooth transition of light to the image side surface of the fourth lens is facilitated, so that the deflection of marginal light cannot be too large, and the influence on the field curvature and astigmatism of the optical lens is reduced.

In some embodiments, the fifth lens element may have a negative focal power, which is beneficial to increase an imaging area of the optical lens and improve the imaging quality of the optical lens. The object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a concave surface, so that the illumination of the optical lens is favorably improved, the brightness of the optical lens at the image surface is improved, and the dark corner is avoided.

In some embodiments, the sixth lens element may have a positive focal power, which is beneficial for converging light rays and reducing the deflection angle of the light rays, so that the light rays are in smooth transition. The object side surface and the image side surface of the sixth lens are convex surfaces, so that the influence of the self coma aberration of the sixth lens on the optical lens is reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the seventh lens element may have a negative focal power, which is beneficial to increasing an imaging area of the optical lens and improving an imaging quality of the optical lens. The object side surface of the seventh lens is a convex surface, the image side surface of the seventh lens is a concave surface, and central field-of-view light rays can be further converged, so that the total length of the optical lens is compressed; meanwhile, the influence of the self curvature of field of the seventh lens on the optical lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the third lens and the fourth lens can be cemented to form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce eccentricity sensitivity of the optical lens, balance aberration of the optical lens, and improve imaging quality of the optical lens; the assembly sensitivity of the optical lens can be reduced, the processing difficulty of the optical lens is further reduced, and the assembly yield of the optical lens is improved.

In some embodiments, a diaphragm for limiting the light beam may be disposed between the first lens and the second lens, and the diaphragm may be disposed near an object-side surface of the second lens, so as to reduce generation of ghost of the optical lens, and to facilitate converging light entering the optical system and reduce a rear aperture of the optical lens.

In some embodiments, the aperture value FNO of the optical lens satisfies: FNO is less than or equal to 1.6. The range is satisfied, the large aperture characteristic is favorably realized, and the image definition can be ensured in a low-light environment or at night.

In some embodiments, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 4.5 and less than 5.0. The optical lens can effectively limit the length of the lens and is beneficial to realizing the miniaturization of the optical lens.

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: IH/f is more than 1.6 and less than 1.9. Satisfying the above range can make the optical lens not only give consideration to the large image plane characteristics, but also have good imaging quality.

In some embodiments, the optical back focus BFL and the effective focal length f of the optical lens satisfy: 1.0 < BFL/f. The method meets the range, is favorable for obtaining balance between good imaging quality and optical back focal length easy to assemble, and reduces the difficulty of the camera module assembly process while ensuring the imaging quality of the optical lens.

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: IH/EPD is more than 2.5 and less than 3.0. The width of the light ray bundle entering the optical lens can be increased, so that the brightness of the optical lens at the image surface is improved, and the dark corner is avoided.

In some embodiments, the maximum field angle FO of the optical lensV, effective working caliber D of first lens object side surface ₁ And the real image height IH corresponding to the maximum field angle satisfies the following conditions: d is more than 0.6 ₁ the/IH/tan (FOV/2) < 0.9. The optical lens has the advantages that the optical lens has a large field angle and a large image plane, the front port diameter is small, and the miniaturization of the optical lens is facilitated.

In some embodiments, the effective focal length f, the maximum field angle FOV, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.6 < (IH/2)/(fXtan (FOV/2)) < 0.7. Satisfying the above range shows that the optical distortion of the optical lens is controlled excellently, and the resolving power of the optical lens is improved

In some embodiments, the effective focal length f of the optical lens and the focal length f of the first lens are different ₁ Satisfies the following conditions: -1.2 < f ₁ The/f is less than 0. Satisfying the above range, the first lens can have a proper negative focal power, and the object-side light can be prevented from being too much diffused, which is beneficial to controlling the aperture of the rear lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the second lens ₂ Satisfies the following conditions: f is more than 0 ₂ The/f is less than 4.0. The second lens has proper positive focal power, so that the working aperture of the optical lens can be reduced by converging light rays, various aberrations of the optical lens can be balanced, and the imaging quality of the optical lens can be improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the third lens are different ₃ Satisfies the following conditions: f is more than 0 ₃ The/f is less than 1.2. The third lens has appropriate positive focal power, so that stable light transition is facilitated, spherical aberration, astigmatism and field curvature of the optical lens are corrected, and imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the fourth lens are ₄ Satisfies the following conditions: -2.0 < f ₄ The/f is less than 0. The fourth lens has appropriate negative focal power, the imaging area of the optical lens is increased, the spherical aberration and the curvature of field of the optical lens are corrected, and the imaging quality of the optical lens is improved.

In some embodimentsEffective focal length f of the optical lens and focal length f of the fifth lens ₅ Satisfies the following conditions: -8.0 < f ₅ The/f is less than 0. The fifth lens has appropriate negative focal power, so that the imaging area of the optical lens can be increased, the spherical aberration, astigmatism and field curvature of the optical lens can be corrected, and the imaging quality of the optical lens can be improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the sixth lens ₆ Satisfies the following conditions: f is more than 0 ₆ The/f is less than 1.8. The sixth lens has appropriate positive focal power, so that stable light transition is facilitated, various aberrations of the optical lens are corrected, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the seventh lens ₇ Satisfies the following conditions: -10.0 < f ₇ The/f is less than 0. The seventh lens has appropriate negative focal power, the imaging area of the optical lens can be increased, various aberrations of the optical lens can be corrected, and the imaging quality of the optical lens can be improved.

In some embodiments, the optical lens has an entrance pupil diameter EPD spaced from the image-side surface of the first lens and the object-side surface of the second lens on the optical axis CT ₁₂ Satisfies the following conditions: 0.9 < CT ₁₂ and/EPD is less than 1.7. The optical lens meets the above range, the light focusing position after the reflection of the object side surface of the second lens is positioned at the rear of the image side surface, the design ghost of the optical lens can be effectively improved, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the object-side radius of curvature R of the second lens element ₃ Satisfies the following conditions: 1.4 < R ₃ The/f is less than 1.9. The range is satisfied, and the marginal field of view light is favorably converged, so that the marginal field of view aberration of the optical lens is reduced, and the ghost risk is reduced.

In some embodiments, the focal length f of the second lens ₂ And center thickness CT ₂ Satisfies the following conditions: f is more than 5.0 ₂ /CT ₂ Is less than 13. The field curvature of the optical lens can be corrected by the aid of the thicker second lens, and imaging quality of the optical lens is improved.

In some embodiments, the third lens has a radius of curvature of the object side R ₅ And the radius of curvature R of the image side surface of the fourth lens ₈ Satisfies the following conditions: -1.5 < R ₅ /R ₈ Is less than 0. Satisfy above-mentioned scope, can make the third lens objective side and the image side of fourth lens obtain the plane of symmetry type, be favorable to reducing the coma of balanced third lens and fourth lens, promote optical lens's image quality.

In some embodiments, the total optical length TTL of the optical lens and the sum Σ CT of the central thicknesses of the first to seventh lenses along the optical axis respectively satisfy: 0.4 <. Sigma CT/TTL < 0.7. The optical lens structure meets the range, can effectively compress the total length of the optical lens, and is beneficial to the structural design and the production process of the optical lens.

In order to make the system have better optical performance, a plurality of aspheric lenses are adopted in the lens, and the 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 a quadric coefficient, and A, B, C, D, E and F are second-order, fourth-order, sixth-order, eighth-order, tenth-order and twelfth-order curved coefficients respectively.

The invention is further illustrated below by means of a number of 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 by the following examples, and any other changes, substitutions, combinations or simplifications which do not depart from the gist of the present invention should be construed as being equivalent replacements 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: a first lens L1, a stop ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter G1, and a cover glass G2.

The first lens L1 has negative focal power, and both the object side surface S1 and the image side surface S2 are concave surfaces;

a diaphragm ST;

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

the third lens L3 has positive focal power, and both the object side surface S5 and the image side surface S6 are convex surfaces;

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

the fifth lens L5 has negative focal power, and the object side surface S9 is a convex surface, and the image side surface S10 is a concave surface;

the sixth lens L6 has positive focal power, and both the object-side surface S11 and the image-side surface S12 are convex surfaces;

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

the third lens L3 and the fourth lens L4 can be glued to form a cemented lens;

the object side surface S15 and the image side surface S16 of the optical filter G1 are both planes;

the object side surface S17 and the image side surface S18 of the protective glass G2 are both planes;

the image formation surface S19 is a plane.

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 this embodiment, the curvature of field curve, F-tan θ distortion, relative illumination, MTF, axial aberration, and homeotropic aberration of the optical lens are shown in fig. 2, 3, 4, 5, 6, and 7, respectively.

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 +/-0.05 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 3 shows an F-tan θ distortion curve of example 1, which shows F-tan θ distortions at different image heights on an image forming plane for light rays of different wavelengths, with the abscissa representing the F-tan θ distortion (unit:%) and the ordinate representing the half field angle (unit: °). As can be seen from the figure, the F-tan theta distortion of the optical lens is controlled within +/-40%, the trend of the F-tan theta distortion curve is smooth, the image compression of the large-angle edge area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-tan theta distortion.

Fig. 4 shows a relative illuminance curve of example 1, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °) and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative illuminance value of the optical lens is still greater than 80% at the maximum half field angle, indicating that the optical lens has excellent relative illuminance.

Fig. 5 shows MTF (modulation transfer function) graphs of embodiment 1, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. It can be seen from the figure that the MTF value of this embodiment is above 0.4 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve decreases uniformly and smoothly in the process from the center to the edge field of view, and has good imaging quality and good detail resolution capability in both low frequency and high frequency.

Fig. 6 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the shift amount of the axial aberration is controlled within ± 20 μm, which indicates that the optical lens can correct the axial aberration well.

Fig. 7 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 (0.55 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 +/-3 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. 8, 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: a first lens L1, a diaphragm ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter G1, and a cover glass G2.

a diaphragm ST;

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

the third lens L3 and the fourth lens L4 may be cemented to form a cemented lens.

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 this embodiment, the curvature of field curve, F-tan θ distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens are respectively shown in fig. 9, 10, 11, 12, 13, and 14.

Fig. 9 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 +/-0.05 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 10 shows an F-tan θ distortion curve of example 2, which shows the F-tan θ distortion of light rays of different wavelengths at different image heights on an image forming plane, with the horizontal axis showing the F-tan θ distortion (unit:%) and the vertical axis showing the half field angle (unit:%). As can be seen from the figure, the F-tan theta distortion of the optical lens is controlled within +/-40%, the trend of the F-tan theta distortion curve is smooth, the image compression of the edge large-angle area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-tan theta distortion.

Fig. 11 shows a relative illuminance curve of example 2, which represents relative illuminance values at different angles of field of view on an imaging plane, with the horizontal axis representing a half field angle (unit: °) and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative luminance value of the optical lens at the maximum half field angle is still greater than 70%, indicating that the optical lens has good relative luminance.

Fig. 12 shows MTF (modulation transfer function) graphs of embodiment 2, which represent lens imaging modulation degrees of different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing MTF values. As can be seen from the figure, the MTF value of the embodiment is above 0.4 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process from the center to the edge field of view, and the image quality and the detail resolution capability are good under the conditions of low frequency and high frequency.

Fig. 13 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the shift amount of the axial aberration is controlled within ± 20 μm, which indicates that the optical lens can correct the axial aberration well.

Fig. 14 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 (0.55 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 +/-3 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. 15, 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: a first lens L1, a stop ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter G1, and a cover glass G2.

The first lens L1 has negative focal power, and the object side surface S1 is a convex surface, and the image side surface S2 is a concave surface;

a diaphragm ST;

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 θ distortion curve, a relative illuminance graph, an MTF graph, an axial aberration graph, and a vertical axis chromatic aberration graph of the optical lens are shown in fig. 16, 17, 18, 19, 20, and 21, respectively.

Fig. 16 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 ± 0.08mm, which indicates that the optical lens can correct the field curvature well.

Fig. 17 shows an F-tan θ distortion curve of example 3, which shows the F-tan θ distortion of light rays of different wavelengths at different image heights on an image forming plane, with the horizontal axis showing the F-tan θ distortion (unit:%) and the vertical axis showing the half field angle (unit:%). As can be seen from the figure, the F-tan theta distortion of the optical lens is controlled within +/-40%, the trend of the F-tan theta distortion curve is smooth, the image compression of the edge large-angle area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-tan theta distortion.

Fig. 18 shows a relative illuminance curve of example 3, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °) and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative illuminance value of the optical lens at the maximum half field angle is still greater than 70%, indicating that the optical lens has good relative illuminance.

Fig. 19 shows MTF (modulation transfer function) graphs of embodiment 3, which represent lens imaging modulation degrees of different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing MTF values. As can be seen from the figure, the MTF value of the embodiment is above 0.4 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process from the center to the edge field of view, and the image quality and the detail resolution capability are good under the conditions of low frequency and high frequency.

Fig. 20 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the shift amount of the axial aberration is controlled within ± 20 μm, which indicates that the optical lens can correct the axial aberration well.

Fig. 21 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 (0.55 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 +/-3 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. 22, 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: a first lens L1, a stop ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter G1, and a cover glass G2.

a diaphragm ST;

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

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 θ distortion curve, a relative illuminance graph, an MTF graph, an axial aberration graph, and a vertical axis chromatic aberration graph of the optical lens are shown in fig. 23, 24, 25, 26, 27, and 28, respectively.

Fig. 23 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 +/-0.08 mm, which shows that the optical lens can well correct the field curvature.

Fig. 24 shows an F-tan θ distortion curve of example 4, which shows F-tan θ distortions at different image heights on an image forming plane for light rays of different wavelengths, with the abscissa showing the F-tan θ distortion (unit:%) and the ordinate showing the half field angle (unit: °). As can be seen from the figure, the F-tan theta distortion of the optical lens is controlled within +/-40%, the trend of the F-tan theta distortion curve is smooth, the image compression of the edge large-angle area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-tan theta distortion.

Fig. 25 shows a relative illuminance curve of example 4, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °) and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative luminance value of the optical lens is still greater than 60% at the maximum half field angle, which indicates that the optical lens has better relative luminance.

Fig. 26 shows MTF (modulation transfer function) graphs of embodiment 4, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. As can be seen from the figure, the MTF value of the present embodiment is above 0.4 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly dropped in the process from the center to the edge field of view, and the image quality and the detail resolution are good in both the low frequency and the high frequency.

Fig. 27 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the shift amount of the axial aberration is controlled within ± 20 μm, which indicates that the optical lens can correct the axial aberration well.

Fig. 28 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 (0.55 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 +/-3 mu m, which shows that the optical lens can excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.

Example 5

Referring to fig. 29, a schematic structural view of an optical lens system according to embodiment 5 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a stop ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter G1, and a cover glass G2.

The first lens L1 has negative focal power, and the object side surface S1 and the image side surface S2 are both concave surfaces;

a diaphragm ST;

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

The relevant parameters of each lens in the optical lens in example 5 are shown in table 5-1.

TABLE 5-1

The surface shape parameters of the aspherical lens of the optical lens in example 5 are shown in table 5-2.

TABLE 5-2

In the present embodiment, the curvature of field curve, F-tan θ distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens are respectively shown in fig. 30, 31, 32, 33, 34, and 35.

Fig. 30 shows a field curvature curve of example 5, 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 ± 0.06mm, which indicates that the optical lens can correct the field curvature well.

Fig. 31 shows an F-tan θ distortion curve of example 5, which shows the F-tan θ distortion of light rays of different wavelengths at different image heights on an image forming plane, with the horizontal axis showing the F-tan θ distortion (unit:%) and the vertical axis showing the half field angle (unit:%). As can be seen from the figure, the F-tan theta distortion of the optical lens is controlled within +/-40%, the trend of the F-tan theta distortion curve is smooth, the image compression of the edge large-angle area is smooth, the definition of the expanded image is effectively improved, and the optical lens can better correct the F-tan theta distortion.

Fig. 32 shows a relative illuminance curve of example 5, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °), and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative luminance value of the optical lens at the maximum half field angle is still greater than 70%, indicating that the optical lens has good relative luminance.

Fig. 33 shows MTF (modulation transfer function) graphs of example 5, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. It can be seen from the figure that the MTF values of the present embodiment are both above 0.4 in the full field of view, and in the range of 0 to 160lp/mm, the MTF curves decrease uniformly and smoothly in the process from the center to the edge field of view, and have good imaging quality and good detail resolution capability in both low and high frequencies.

Fig. 34 shows an axial aberration curve of example 5, 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: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the shift amount of the axial aberration is controlled within ± 20 μm, which indicates that the optical lens can correct the axial aberration well.

Fig. 35 shows a vertical axis chromatic aberration curve of example 5, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.55 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 +/-4 mu m, which shows that the optical lens can excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.

Please refer to table 6, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the aperture FNO, the real image height IH, and the maximum field angle FOV of the optical lens, and the values corresponding to each conditional expression in the embodiments.

TABLE 6

In summary, the optical lens of the embodiment of the invention realizes the advantages of large field angle, large aperture, high definition and high imaging quality by reasonably matching the combination of the lens shapes and the focal powers among the lenses.

In the description of the specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

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, in order from an object side to an image plane along an optical axis:

a diaphragm;

the real image height IH corresponding to the effective focal length f, the maximum field angle FOV and the maximum field angle of the optical lens meets the following requirements: 0.6 < (IH/2)/(fXtan (FOV/2)) < 0.7.

2. An optical lens according to claim 1, wherein the total optical length TTL and the effective focal length f satisfy: TTL/f is more than 4.5 and less than 5.0.

3. 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: IH/f is more than 1.6 and less than 1.9.

4. An optical lens according to claim 1, characterized in that the optical back focus BFL of the optical lens and the effective focal length f satisfy: 1.0 < BFL/f.

5. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f of the fifth lens ₅ Satisfies the following conditions: -8.0 < f ₅ /f＜0。

6. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f of the seventh lens ₇ Satisfies the following conditions: -10.0 < f ₇ /f＜0。

7. According toThe optical lens of claim 1, characterized in that an entrance pupil diameter EPD of the optical lens is separated from an axial distance CT between an image side surface of the first lens and an object side surface of the second lens ₁₂ Satisfies the following conditions: 0.9 < CT ₁₂ /EPD＜1.7。

8. An optical lens as recited in claim 1, wherein the effective focal length f of the optical lens and the radius of curvature R of the object side of the second lens ₃ Satisfies the following conditions: 1.4 < R ₃ /f＜1.9。

9. An optical lens according to claim 1, characterized in that the focal length f of the second lens ₂ And center thickness CT ₂ Satisfies the following conditions: f is more than 5.0 ₂ /CT ₂ ＜13。

10. An optical lens according to claim 1, wherein a total optical length TTL of the optical lens and a sum Σ CT of central thicknesses of the first lens to the seventh lens along an optical axis, respectively, satisfy: 0.4 <. Sigma CT/TTL < 0.7.