CN115494623B

CN115494623B - Optical lens

Info

Publication number: CN115494623B
Application number: CN202211417957.7A
Authority: CN
Inventors: 王昆; 魏文哲; 王克民
Original assignee: Jiangxi Lianchuang Electronic Co Ltd
Current assignee: Jiangxi Lianchuang Electronic Co Ltd
Priority date: 2022-11-14
Filing date: 2022-11-14
Publication date: 2023-03-14
Anticipated expiration: 2042-11-14
Also published as: CN115494623A

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: the first lens with focal power, its object side is a convex surface, the image side is a concave surface; a second lens having a negative refractive power, the object side surface of which is concave; a third lens with positive focal power, wherein the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; a fourth lens having a positive refractive power, both the object-side surface and the image-side surface of the fourth lens being convex; a fifth lens element having a positive refractive power, the object-side surface and the image-side surface of the fifth lens element being convex; a sixth lens element having a negative refractive power, wherein both the object-side surface and the image-side surface are concave; a seventh lens having a positive refractive power, an object-side surface of which is convex; effective focal length f of optical lens and focal length f of first lens ₁ Satisfies the following conditions: 5.0 < | f ₁ The/| is less than 50.0. The optical lens has the advantages of large field of view, large aperture and miniaturization.

Description

Optical lens

Technical Field

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

Background

With the development of automobile intelligence, the driving assistance function of the vehicle is gradually enhanced, wherein visual information collection is a core tool. With the improvement of the automatic driving level, the requirements on the vehicle-mounted camera are gradually increased, especially the front camera. The front camera can enhance the active safety and driver assistance functions, such as Automatic Emergency Braking (AEB), adaptive Cruise Control (ACC), lane Keeping Assist System (LKAS), traffic Jam Assist (TJA), and the like, and has the disadvantages of a large number of lenses, an excessively long optical total length, and the like while meeting the advantages of high resolution, a large field angle, good environmental adaptability, and the like, and is not beneficial to the miniaturization of an electronic system.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an optical lens having advantages of a large field of view, a large aperture, and a small size.

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

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

the first lens with focal power, its object side is a convex surface, the image side is a concave surface;

a second lens having a negative refractive power, the object side surface of which is concave;

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

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

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

a sixth lens element having a negative refractive power, both the object-side surface and the image-side surface of which are concave surfaces;

a seventh lens having positive refractive power, an object-side surface of which is convex;

an effective focal length f of the optical lens and a focal length f of the first lens ₁ Satisfies the following conditions: 5.0 < | f ₁ /f|＜50.0。

Preferably, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is less than 5.1.

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 1.4 and less than 1.6.

Preferably, the effective working aperture D of the object side surface of the first lens is ₁ Effective working aperture D of half field angle with object side surface of the first lens _θ Satisfies the following conditions: d is more than 0.7 _θ /D ₁ ＜0.85。

Preferably, the real image height IH corresponding to the maximum field angle of the optical lens and the real image height IH corresponding to the half field angle of the optical lens _θ Satisfies the following conditions: IH of 0.6 _θ /IH＜0.8。

Preferably, the maximum field angle FOV of the optical lens, the true image height IH corresponding to the maximum field angle and the effective working aperture D of the object side surface of the first lens are all the same ₁ Satisfies the following conditions: d is more than 0.25 ₁ /IH/tan(FOV/2)＜0.35。

Preferably, the effective focal length f of the optical lens and the combined focal length f of the first lens and the second lens are equal ₁₂ Satisfies the following conditions: -1.5 < f ₁₂ /f＜0。

Preferably, the object side curvature radius R of the first lens ₁ Radius of curvature R of image side ₂ Satisfies the following conditions: r is more than or equal to 1.0 ₁ /R ₂ ＜1.5。

Preferably, the object side rise Sag of the first lens ₁ And an object side surface of the first lens is communicated with a light semi-aperture d ₁ And an image side rise Sag of the first lens ₂ And the image side surface of the first lens is communicated with the light semi-aperture d ₂ Respectively satisfy: | Sag ₁ /d ₁ |＜0.3，|Sag ₂ /d ₂ |＜0.4。

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 < 0.6.

Compared with the prior art, the invention has the beneficial effects that: the optical lens of the application combines with focal power through the lens shape between each lens of reasonable collocation, has realized possessing big visual field, big light ring and miniaturized advantage simultaneously.

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 illuminance curve of the optical lens in embodiment 1 of the present invention;

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

fig. 6 is a graph showing axial aberration of the optical lens in embodiment 1 of the present invention;

FIG. 7 is a vertical axis chromatic aberration diagram of an 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 an 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 illuminance 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 curve diagram of the 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 an 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 the optical lens in embodiment 4 of the present invention;

fig. 27 is a graph showing axial aberration of the optical lens in embodiment 4 of the present invention;

fig. 28 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 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: 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 element has a convex image-side surface and a concave image-side surface, which is advantageous for collecting light rays with a large field of view as much as possible into the rear optical lens. The first lens can be provided with an aspheric mirror surface, so that the central area of the optical lens has large-angle resolution, and the resolution is improved. The first lens can be made of a material with a high refractive index, so that the aperture of the front end of the optical lens can be reduced, and the imaging quality can be improved.

In some embodiments, the second lens element may have a negative focal power, and the negative focal power of the front end of the optical lens element can be shared, so that the optical lens element is beneficial to avoiding the excessive light deflection caused by the over-concentration of the focal power of the first lens element, and the difficulty in correcting chromatic aberration of the optical lens element is reduced. The object side surface of the second lens is a concave surface, so that light rays which are emitted after passing through the first lens can be collected, the light ray trend is in stable transition, and the imaging quality of the optical lens is 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 of the third lens is a convex surface, the image side surface of the third lens is a concave surface, and therefore light rays in the edge field of view can be converged, the converged light rays can smoothly enter the rear-end optical system, the field curvature generated by the third lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the fourth 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 fourth lens are convex surfaces, so that coma aberration generated by the fourth lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the fifth 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 fifth lens are convex surfaces, so that coma aberration generated by the fifth lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the sixth 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 and the image side surface of the sixth lens are both concave surfaces, so that light rays in the edge field of view can be converged, the converged light rays can smoothly enter the rear-end optical system, coma generated by the sixth lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the seventh 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 of the seventh lens is a convex surface, so that the illumination of the optical lens is favorably improved, the brightness of the optical lens at an image surface is improved, and the generation of a dark corner is avoided.

In some embodiments, the fifth lens and the sixth 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 third lens and the fourth lens or between the fourth lens and the fifth lens, and the diaphragm may be disposed near an object-side surface of the fourth lens or the fifth lens, which can reduce generation of optical lens ghost, and is beneficial to converging light rays entering the optical system and reducing 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 1.80. 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 maximum field angle FOV of the optical lens satisfies: FOV is less than or equal to 160 degrees. The wide-angle detection method meets the range, is beneficial to realizing wide-angle characteristics, can acquire more scene information and meets the requirement of large-range detection.

In some embodiments, the incident angle CRA of the maximum field angle chief ray of the optical lens on the image plane satisfies: CRA < 25 DEG 15 deg. Satisfying the above range, the allowable error value between the CRA of the optical lens and the CRA of the chip photosensitive element can be made larger, and the adaptability of the optical lens to the image sensor can be improved.

In some embodiments, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is less than 5.1. The optical lens system satisfies the above range, can effectively limit the length of the lens, and realizes 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 1.4 and less than 1.6. 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: BFL/f is not less than 0.4. 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 2.9. 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 FOV of the optical lens, the true image height IH corresponding to the maximum field angle, and the object-side effective working aperture D of the first lens ₁ Satisfies the following conditions: d is more than 0.25 ₁ the/IH/tan (FOV/2) < 0.35. 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 working aperture D of the object side surface of the first lens ₁ Effective working aperture D at half field angle with object side surface of first lens _θ Satisfies the following conditions: d is more than 0.7 _θ /D ₁ Is less than 0.85. The height of the central field-of-view light on the object side surface of the first lens is far higher than that of the peripheral field-of-view light, namely, the height of the different field-of-view light on the object side surface of the first lens is adjusted, so that the height of the different field-of-view light on the imaging surface can be controlled more favorably.

In some embodiments, the real image height IH corresponding to the maximum field angle and the real image height IH corresponding to the half field angle _θ Satisfies the following conditions: IH of 0.6 _θ IH is less than 0.8. The method meets the range, the occupation ratio of the imaging range of the central field of view in the whole imaging range can be improved, the larger the imaging range is, the more the number of pixels occupied by the corresponding chip surface is, and therefore more detailed information can be obtained.

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: 5.0 < | f ₁ The/| is less than 50.0. Satisfying the above range, the first lens may be made to haveThe larger focal length ratio is beneficial to the relaxation of the change of the refraction angle of incident light, avoids the excessive aberration caused by the over-strong refraction change, is beneficial to more light rays entering a rear optical system, and increases the illumination to improve the imaging quality of the optical 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: -2.0 < f ₂ The/f is less than 0. Satisfying the above range, the second lens can have a proper negative focal power, and can share the negative focal power of the front end of the optical lens, thereby being beneficial to avoiding the overlarge light deflection caused by the over-concentration of the focal power of the first lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the third lens are ₃ Satisfies the following conditions: f is more than 0 ₃ The/f is less than 2.5. Satisfying above-mentioned scope, can making the third lens have appropriate positive focal power, be favorable to assembling light and reduce light deflection angle simultaneously, let the light trend smooth transition, promote optical lens's the formation of image quality.

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: f is more than 0 ₄ The/f is less than 2.0. Satisfying above-mentioned scope, can making the fourth lens have appropriate positive focal power, be favorable to gathering reducing light deflection angle when light, let the light trend smooth transition, promote optical lens's the formation of image quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the fifth lens ₅ Satisfies the following conditions: f is more than 0 ₅ The/f is less than 3.0. The fifth lens has appropriate positive focal power, light can be smoothly transited, 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 sixth lens element ₆ Satisfies the following conditions: -1.5 < f ₆ The/f is less than 0. The sixth lens element has appropriate negative focal power, so that 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 effective focal length f of the optical lens and the focal length f of the seventh lens ₇ Satisfies the following conditions: 2.0 < f ₇ The/f is less than 15.0. The seventh lens has proper positive focal power, so that various aberrations of the optical lens can be balanced, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the first and second lenses ₁₂ Satisfies the following conditions: -1.5 < f ₁₂ The/f is less than 0. Satisfy above-mentioned scope, through the focus of rational distribution first lens and second lens, be favorable to balancing all kinds of aberrations, promote optical lens's imaging quality.

In some embodiments, the radius of curvature of the object-side surface of the first lens, R ₁ Radius of curvature R of image-side surface ₂ Satisfies the following conditions: r is more than or equal to 1.0 ₁ /R ₂ Is less than 1.5. The optical lens can ensure that the object side surface and the image side surface of the first lens have similar surface types, is favorable for reducing the spherical aberration and the field curvature of the first lens and improves the imaging quality of the optical lens.

In some embodiments, the rise Sag of the object-side surface of the first lens ₁ Light-transmitting semi-aperture d with object side surface of first lens ₁ And rise Sag of the image-side surface of the first lens ₂ Light-transmitting semi-aperture d with image side surface of first lens ₂ Respectively satisfy: | Sag ₁ /d ₁ |＜0.3，|Sag ₂ /d ₂ And | is less than 0.4. The coating film thickness can be adjusted according to the shape of the object side surface of the first lens, so that the coating film thickness is uniform; meanwhile, edge light rays are transmitted to the rear end of the optical lens, and the imaging quality of the optical lens is improved.

In some embodiments, the total optical length TTL of the optical lens and the sum Σ CT of the central thicknesses of the first lens to the seventh lens along the optical axis, respectively, satisfy: 0.4 <. Sigma CT/TTL < 0.6. 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 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 are the coefficients of the second order, the fourth order, the sixth order, the eighth order, the tenth order and the twelfth order curved surface 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: a first lens L1, a second lens L2, a third lens L3, a stop ST, 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 of the first lens L is a convex surface, and the image side surface S2 of the first lens L is a concave surface;

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

the third lens L3 has positive focal power, and the object side surface S5 is a convex surface, and the image side surface S6 is a concave surface;

a diaphragm ST;

the fourth lens L4 has positive focal power, and both the object side surface S7 and the image side surface S8 are convex surfaces;

the fifth lens L5 has positive focal power, and both the object side surface S9 and the image side surface S10 are convex surfaces;

the sixth lens L6 has negative focal power, and the object side surface S11 and the image side surface S12 are both concave surfaces;

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

the fifth lens L5 and the sixth lens L6 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 the present embodiment, a field curvature graph, an F-tan θ distortion graph, a relative illumination graph, an MTF 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, fig. 5, fig. 6, and fig. 7.

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 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 +/-90%, and the trend of the F-tan theta distortion curve is smooth, so that the definition of an 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 luminance value of the optical lens is still greater than 50% at the maximum half field angle, which indicates that the optical lens has better relative luminance.

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. As can be seen from the figure, the MTF value of the embodiment is above 0.3 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 has better imaging quality and better detail resolution capability under the conditions of 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 amount of shift of the axial aberration is controlled within ± 15 μm, indicating 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 +/-2 μm, 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 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 second lens L2, a third lens L3, a stop ST, 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;

the second lens L2 has negative focal power, and both the object side surface S3 and the image side surface S4 are concave surfaces;

a diaphragm ST;

the fourth lens L4 has positive focal power, and both the object-side surface S7 and the image-side surface S8 are convex surfaces;

the fifth lens L5 and the sixth lens L6 may be cemented to constitute a cemented lens.

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 +/-0.02 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 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 +/-90%, and the trend of the F-tan theta distortion curve is smooth, so that the definition of an 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 is still greater than 50% at the maximum half field angle, which indicates that the optical lens has better relative luminance.

Fig. 12 shows MTF (modulation transfer function) graphs of embodiment 2, 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 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 amount of shift of the axial aberration is controlled within ± 10 μm, indicating that the optical lens can excellently correct the axial aberration.

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 +/-2 μm, 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 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 second lens L2, a third lens L3, a stop ST, 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 sixth lens element L6 has a negative focal power, and has a concave object-side surface S11 and a concave image-side surface S12;

the seventh lens L7 has positive refractive power, and both the object-side surface S13 and the image-side surface S14 are convex surfaces;

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 +/-0.04 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 17 shows an F-tan θ distortion curve of example 3, 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 +/-90%, and the trend of the F-tan theta distortion curve is smooth, so that the definition of an 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 is still greater than 80% at the maximum half field angle, indicating that the optical lens has excellent relative illuminance.

Fig. 19 shows MTF (modulation transfer function) graphs of embodiment 3, 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 embodiment is above 0.3 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 has better imaging quality and better detail resolution capability 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 amount of shift of the axial aberration is controlled within ± 15 μm, indicating 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 +/-2 μm, 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 4

Fig. 22 is a schematic structural view of an optical lens system according to embodiment 4 of the present invention, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a stop ST, 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 positive focal power, and the object side surface S1 of the first lens L is a convex surface, and the image side surface S2 of the first lens L is a concave surface;

a diaphragm ST;

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

TABLE 4-1

The parameters of the surface shape 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 +/-0.05 mm, which shows that the optical lens can excellently correct the field curvature.

Fig. 24 shows an F-tan θ distortion curve of example 4, 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 +/-90%, and the trend of the F-tan theta distortion curve is smooth, so that the definition of an 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 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. 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 embodiment is above 0.3 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 better under the conditions of low frequency and 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 amount of shift of the axial aberration is controlled within ± 15 μm, indicating 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.

Please refer to table 5, which shows the corresponding optical characteristics of 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 corresponding values of each conditional expression in the embodiments.

TABLE 5

In summary, the optical lens of the embodiment of the invention realizes the advantages of large field of view, large aperture and miniaturization by reasonably matching the combination of the lens shape and the focal power among the lenses.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean 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 sixth lens element having a negative refractive power, wherein both the object-side surface and the image-side surface are concave;

a seventh lens having a positive refractive power, an object-side surface of which is convex;

an effective focal length f of the optical lens and a focal length f of the first lens ₁ Satisfies the following conditions: 5.0 < | f ₁ /f|＜50.0；

A real image height IH corresponding to the maximum field angle and a half field angle of the optical lens _θ Satisfies the following conditions: IH of 0.6 _θ /IH＜0.8。

2. An optical lens according to claim 1, wherein the total optical length TTL and the effective focal length f satisfy: TTL/f is less than 5.1.

3. The optical lens according to claim 1, wherein 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 1.4 and less than 1.6.

4. An optical lens barrel according to claim 1, wherein the first lens has an object side effective working aperture D ₁ Effective working aperture D of half field angle with object side surface of the first lens _θ Satisfies the following conditions: d is more than 0.7 _θ /D ₁ ＜0.85。

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 third lens are ₃ Satisfies the following conditions: f is more than 0 ₃ /f＜2.5。

6. The optical lens of claim 1, wherein the maximum field angle FOV of the optical lens, the true image height IH corresponding to the maximum field angle, and the object-side effective working aperture D of the first lens ₁ Satisfies the following conditions: d is more than 0.25 ₁ /IH/tan(FOV/2)＜0.35。

7. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the combined focal length f of the first and second lens are such that ₁₂ Satisfies the following conditions: -1.5 < f ₁₂ /f＜0。

8. An optical lens barrel according to claim 1, wherein the first lens has an object side curvature radius R ₁ Radius of curvature R of image side ₂ Satisfies the following conditions: r is more than or equal to 1.0 ₁ /R ₂ ＜1.5。

9. The optical lens of claim 1 wherein the object side rise Sag of the first lens ₁ And an object side surface of the first lens is communicated with a light semi-aperture d ₁ And an image-side rise Sag of the first lens ₂ And the image side surface of the first lens is communicated with the light semi-aperture d ₂ Respectively satisfy: | Sag ₁ /d ₁ |＜0.3，|Sag ₂ /d ₂ |＜0.4。

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 < 0.6.