CN118033874A

CN118033874A - Optical lens

Info

Publication number: CN118033874A
Application number: CN202410418140.4A
Authority: CN
Inventors: 喻永平; 陈伟建; 王克民
Original assignee: Jiangxi Lianchuang Electronic Co Ltd
Current assignee: Jiangxi Lianchuang Electronic Co Ltd
Priority date: 2024-04-09
Filing date: 2024-04-09
Publication date: 2024-05-14

Abstract

The invention provides an optical lens, seven lenses altogether, including in order from the object side to the imaging surface along the optical axis: the first lens with negative focal power has a convex object side surface and a concave image side surface; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a third lens having positive optical power, both the object-side surface and the image-side surface of which are convex; a fourth lens element with positive refractive power having a concave object-side surface and a convex image-side surface; a fifth lens element with positive refractive power having convex object-side and image-side surfaces; a sixth lens element with negative refractive power having concave object-side and image-side surfaces; the object side surface of the seventh lens with positive focal power is a convex surface, and the image side surface of the seventh lens is a concave surface. The optical lens provided by the invention has one or more advantages of large aperture, large field angle, high imaging quality and the like through specific surface shape collocation and reasonable focal power distribution.

Description

Optical lens

Technical Field

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

Background

Along with the continuous improvement of the requirements of people on driving experience, the vehicle-mounted application optical lens is increasingly used in intelligent driving, and the position of the vehicle-mounted optical lens in the related industries of automobiles is continuously improved.

Advanced Driving Assistance Systems (ADASs) play an important role in intelligent driving, and collect environmental information through various lenses in combination with sensors to ensure driving safety of drivers. In addition to the light, thin, short, small, and high-pixel and high-resolution characteristics of the conventional ADAS system lens, the optical lens is required to be capable of clearly imaging under a low-illuminance condition, so that it is required to develop an optical lens with good imaging effect.

Disclosure of Invention

In view of the foregoing, an object of the present invention is to provide an optical lens having an advantage of excellent imaging quality.

The invention adopts the technical scheme that:

an optical lens comprising seven lenses in order from an object side to an imaging surface along an optical axis:

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

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

a third lens having positive optical power, both the object-side surface and the image-side surface of which are convex;

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

A fifth lens element with positive refractive power having convex object-side and image-side surfaces;

A sixth lens element with negative refractive power having concave object-side and image-side surfaces;

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

The real image height ih corresponding to the maximum half field angle of the optical lens, the effective focal length f of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.42< ih/(f×tan (FOV/2)) <0.52.

Further preferably, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.6< BFL/f <0.8.

Further preferably, the maximum field angle FOV of the optical lens, the effective focal length f of the optical lens, and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 60 ° < (fov×f)/IH <70 °.

Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -10< f2/f < -6.

Further preferably, a combined focal length f123 of the first lens, the second lens, and the third lens and a combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: 1.5< f123/f4567<2.1.

Further preferably, the object-side radius of curvature R7 of the fourth lens and the image-side radius of curvature R8 of the fourth lens satisfy: 0.8< (R7-R8)/(R7+R8) <1.

Further preferably, the object-side light-transmitting half-aperture d7 of the fourth lens and the object-side light-transmitting half-aperture sagittal height Sag7 of the fourth lens satisfy: -0.09< Sag7/d7< -0.01.

Further preferably, the object-side radius of curvature R1 of the first lens, the image-side radius of curvature R2 of the first lens and the center thickness CT1 of the first lens satisfy: 5.8< R1/(R2+CT1) <18.8.

Further preferably, the object-side surface light-transmitting half aperture d1 of the first lens, the real image height ih corresponding to the maximum half field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.8< d1/ih/tan (FOV/2) <1.1.

Further preferably, the image-side light-transmitting half aperture d6 of the third lens and the object-side light-transmitting half aperture d7 of the fourth lens satisfy: 1.6< d6/d7<2.2.

According to the optical lens provided by the invention, seven lenses with specific focal power are adopted, and through specific surface shape collocation and reasonable focal power distribution, the imaging quality of the optical lens can be improved, the aberration is reduced, the imaging quality of the optical lens is improved, and the lens has one or more advantages of large aperture, large field angle, high imaging quality and the like.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic structural diagram of an optical lens in embodiment 1 of the present invention.

Fig. 2 is a graph showing a field curvature of an optical lens in embodiment 1 of the present invention.

FIG. 3 is a graph showing F-Tanθ distortion of an optical lens in example 1 of the present invention.

Fig. 4 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 1 of the present invention.

Fig. 5 is an axial aberration diagram of the optical lens in embodiment 1 of the present invention.

Fig. 6 is an MTF graph of the optical lens in example 1 of the present invention.

Fig. 7 is a graph showing the relative illuminance of the optical lens in embodiment 1 of the present invention.

Fig. 8 is a schematic structural diagram of an optical lens in embodiment 2 of the present invention.

Fig. 9 is a graph showing a field curvature of an optical lens in embodiment 2 of the present invention.

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

Fig. 11 is a vertical axis chromatic aberration chart of the optical lens in embodiment 2 of the present invention.

Fig. 12 is an axial aberration diagram of the optical lens in embodiment 2 of the present invention.

Fig. 13 is an MTF graph of the optical lens in example 2 of the present invention.

Fig. 14 is a graph showing the relative illuminance of the optical lens in embodiment 2 of the present invention.

Fig. 15 is a schematic structural diagram of an optical lens in embodiment 3 of the present invention.

Fig. 16 is a graph showing the field curvature of an optical lens in embodiment 3 of the present invention.

FIG. 17 is a graph showing F-Tanθ distortion of an optical lens in example 3 of the present invention.

Fig. 18 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 3 of the present invention.

Fig. 19 is an axial aberration diagram of the optical lens in embodiment 3 of the present invention.

Fig. 20 is an MTF graph of the optical lens in example 3 of the present invention.

Fig. 21 is a graph showing the relative illuminance of the optical lens in embodiment 3 of the present invention.

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

Detailed Description

For a better understanding of the application, various aspects of the application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed description are merely illustrative of embodiments of the application and are not intended to 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 the present specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. Accordingly, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present invention.

In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. In particular, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are 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, then 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 referred to as the object side of the lens, and the surface of each lens closest to the imaging plane is referred to as the image side of the lens.

It will be further understood that the terms "comprises," "comprising," "includes," "including," "having," "containing," 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. Furthermore, when a statement such as "at least one of the following" appears after a list of features that are listed, the entire listed feature is modified instead of modifying a separate element in the list. Furthermore, when describing embodiments of the application, use of "may" means "one or more embodiments of the application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.

The optical lens provided by the embodiment of the invention consists of seven lenses, and the seven lenses are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens in sequence from an object side to an imaging surface along an optical axis.

In some embodiments, the first lens may have a negative optical power, with a convex object-side surface and a concave image-side surface. The second lens element may have negative refractive power, wherein an object-side surface thereof is concave and an image-side surface thereof is convex. The third lens may have positive optical power, and both the object side and the image side thereof are convex. The fourth lens element may have positive refractive power, wherein an object-side surface thereof is concave and an image-side surface thereof is convex.

The fifth lens element may have positive optical power, and both the object-side surface and the image-side surface thereof may be convex. The sixth lens element may have negative refractive power, and both the object-side surface and the image-side surface thereof may be concave. The seventh lens element may have positive refractive power, wherein an object-side surface thereof is convex and an image-side surface thereof is concave.

In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the third lens and the fourth lens. It will be appreciated that the aperture is used to limit the amount of light entering to vary the brightness of the image. In addition, when the diaphragm is located between the third lens and the fourth lens, the diaphragm can reasonably distribute the actions of the first lens to the seventh lens, for example, the first lens, the second lens and the third lens can be used for receiving light rays to a greater extent, and the fourth lens to the seventh lens can be used for correcting the action of aberration, which is beneficial to balancing the structure of the whole optical system. Further, when the diaphragm is located between the third lens and the fourth lens, correction of the diaphragm aberration is facilitated.

In some embodiments, the optical lens may further include an optical filter and a protective glass, and the optical filter and the protective glass may be disposed between the seventh lens and the imaging surface in order along the optical axis. The optical filter is used for filtering the interference light and preventing the interference light from reaching the imaging surface of the optical lens to influence normal imaging. The protective glass plays a role in protecting the optical lens, prevents the photosensitive chip from being damaged, can improve the anti-impact and scratch-resistant capabilities of the optical lens, and has little influence on the imaging quality of the optical lens.

In some embodiments, the true image height ih, the effective focal length f of the optical lens, and the maximum field angle FOV of the optical lens corresponding to the maximum half field angle of the optical lens satisfy: 0.42< ih/(f×tan (FOV/2)) <0.52. The above range is satisfied, distortion can be controlled within a reasonable range, and imaging quality is improved.

In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.6< BFL/f <0.8. The optical lens meets the range, can keep longer back focus, is beneficial to adjusting the focal power distribution of each lens, and ensures that various aberrations of the optical lens have more optimization space.

In some embodiments, the maximum field angle FOV of the optical lens, the effective focal length f of the optical lens, and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 60 ° < (fov×f)/IH <70 °. The above range is satisfied, so that the optical distortion is controlled, and the lens resolution is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -10< f2/f < -6. Satisfying the above range, the degree of deflection of the light from the first lens can be reduced, so that the light is smoothly proceeding, and the aberration generated by the front-end lens is balanced.

In some embodiments, the combined focal length f123 of the first, second, and third lenses and the combined focal length f4567 of the fourth, fifth, sixth, and seventh lenses satisfy: 1.5< f123/f4567<2.1. The range is satisfied, the focal power duty ratio of the lens groups before and after the diaphragm can be reasonably distributed, the relative illumination of the lens is increased, and the imaging quality of the lens is improved.

In some embodiments, the object-side radius of curvature R7 of the fourth lens and the image-side radius of curvature R8 of the fourth lens satisfy: 0.8< (R7-R8)/(R7+R8) <1. The surface shapes of the object side surface and the image side surface of the fourth lens can be limited by meeting the range, and the correction difficulty of the spherical aberration and the chromatic aberration of the subsequent lens is reduced; meanwhile, smooth light trend is facilitated, as many marginal view field light beams as possible are transmitted to the rear end of the optical lens, and the relative illumination of the optical lens is improved.

In some embodiments, the object-side light-transmitting half-aperture d7 of the fourth lens and the object-side light-transmitting half-aperture sagittal height Sag7 of the fourth lens satisfy: -0.09< Sag7/d7< -0.01. The range is satisfied, the central depression degree of the object side surface of the fourth lens can be limited, and the aberration correction difficulty of the edge view field is reduced.

In some embodiments, the object-side radius of curvature R1 of the first lens, the image-side radius of curvature R2 of the first lens, and the center thickness CT1 of the first lens satisfy: 5.8< R1/(R2+CT1) <18.8. The correction difficulty of the distortion of the edge view field can be reduced by meeting the above range, and the distortion is controlled within a reasonable range.

In some embodiments, the object-side light-passing half-aperture d1 of the first lens, the real image height ih corresponding to the maximum half field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.8< d1/ih/tan (FOV/2) <1.1. The aperture, the angle of view and the image plane size of the front end of the optical lens can be balanced.

In some embodiments, the image-side light-transmitting half-aperture d6 of the third lens element and the object-side light-transmitting half-aperture d7 of the fourth lens element satisfy: 1.6< d6/d7<2.2. The range is satisfied, and the aperture ratio of two adjacent surfaces of the front lens group and the rear lens group is controlled, so that the light trend is limited in a reasonable range, and the illumination of the imaging surface is uniform.

In some embodiments, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.7< IH/f <2.1. The range is met, the wide angle is provided, and the shooting range of the lens is enlarged; meanwhile, the lens has a large image plane, and the imaging quality of the lens is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.6< f1/f < -1.8. The incidence angle of the light can be reduced by meeting the above range, and the collection of light with large angle can be realized.

In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 3.5< f4/f <5.2. The lens aberration can be balanced and the imaging quality can be improved by meeting the above range.

In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.4< f5/f <1.9. The range is satisfied, light rays can be converged, and chromatic aberration can be corrected by matching with the sixth lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.4< f6/f < -1. The imaging area of the optical lens can be increased and the imaging quality can be improved by meeting the above range.

In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 2.7< f7/f <3.8. The optical lens satisfies the above range, can balance various aberrations, and improves the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the combined focal length f4567 of the fourth, fifth, sixth, and seventh lenses satisfy: 2.3< f4567/f <2.9. The range is satisfied, so that the rear end lens group has proper positive focal power, more light beams are effectively transmitted to the imaging surface, and the imaging quality is improved.

In some embodiments, the effective focal length f of the optical lens and the object-side radius of curvature R1 of the first lens satisfy: 10< R1/f <28. The above range is satisfied, and the shape of the object side surface of the first lens can be limited, so that the first lens can reduce the deflection degree of the light on the basis of receiving the light with a large angle of view.

In some embodiments, the effective focal length f of the optical lens and the object-side radius of curvature R7 of the fourth lens satisfy: -50< R7/f < -40. The shape of the object side surface of the fourth lens can be limited by meeting the range, so that the fourth lens can reduce the deflection degree of the light on the basis of receiving the light with a large angle of view.

In some embodiments, the focal length f4 of the fourth lens and the object-side radius of curvature R7 of the fourth lens satisfy: -14< R7/f4< -7. The above range is satisfied, the shape of the object side surface of the fourth lens can be limited, the duty ratio of stray light is reduced, and the imaging quality of the lens is improved.

In some embodiments, the object-side radius of curvature R13 of the seventh lens and the image-side radius of curvature R14 of the seventh lens satisfy: -1.9< (r13+r14)/(r13—r14) < -1.3. The surface shapes of the object side surface and the image side surface of the seventh lens can be limited by meeting the above range, the image height is increased by controlling the edge view field beam trend, and the off-axis aberration of the optical lens is reduced.

In some embodiments, the object-side light-transmitting half-aperture d1 of the first lens and the object-side light-transmitting half-aperture sagittal height Sag1 of the first lens satisfy: 0.03< Sag1/d1<0.09. The lens has the advantages that the range is met, the central bulge degree of the object side surface of the first lens can be limited, and the subsequent lens distortion correction difficulty is reduced on the premise that the condition of receiving light rays with a large angle of view is met.

In some embodiments, the center thickness CT1 of the first lens along the optical axis and the edge thickness ET1 of the first lens satisfy: 1.6< ET1/CT1<4.9. The range is satisfied, the edge-to-thickness ratio of the first lens can be limited, the capability of correcting the marginal field aberration is improved, and the lens processing difficulty is reduced.

In some embodiments, the sum Σat of the optical total length TTL of the optical lens and the separation distance along the optical axis between the first lens to the seventh lens satisfies: 2.7< TTL/ΣAT <4.7. The above range is satisfied, the TTL/Sigma AT is limited in a reasonable range, so that the system has enough interval space, and the degree of freedom of the change of the lens surface is higher, thereby the optical lens obtains stronger image quality.

In some embodiments, the object-side light-passing half-caliber sagittal height Sag5 of the third lens and the image-side light-passing half-caliber sagittal height Sag6 of the third lens satisfy: 10.8< Sag5/Sag6< -8.1. The range is satisfied, the sagittal height of the object side surface and the image side surface of the third lens is limited, the shape of the third lens is effectively restrained, and the aberration correction difficulty of the rear end lens is reduced.

In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens may be spherical lenses or aspherical lenses, and compared with spherical structures, the aspherical structures can effectively reduce the aberration of the optical system, so that the number of lenses and the size of the lenses are reduced, and miniaturization of the lens is better achieved. More specifically, the first lens, the third lens, the fifth lens and the sixth lens of the present invention are spherical lenses, and the second lens, the fourth lens and the seventh lens are aspherical lenses.

In various embodiments of the present invention, when an aspherical lens is used as the lens, each aspherical surface shape of the optical lens satisfies the following equation:

；

Wherein z is the distance between the curved surface and the curved surface vertex in the optical axis direction, h is the distance between the optical axis and the curved surface, c is the curvature of the curved surface vertex, K is the quadric surface coefficient, B, C, D, E, F is the fourth-order, sixth-order, eighth-order, tenth-order and twelfth-order surface coefficients respectively.

The invention is further illustrated in the following examples. In various embodiments, the thickness, radius of curvature, and material selection portion of each lens in the optical lens may vary, and for specific differences, reference may be made to the parameter tables of the various embodiments. The following examples are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and any other changes, substitutions, combinations or simplifications that do not depart from the gist of the present invention are intended to be equivalent substitutes within the scope of the present invention.

Example 1

Referring to fig. 1, a schematic structural diagram of an optical lens 100 provided in embodiment 1 of the present invention is shown, where the optical lens 100 includes, in order from an object side to an imaging plane along an optical axis: the first lens L1, the second lens L2, the third lens L3, the stop ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the filter G1, and the cover glass G2.

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

the second lens element L2 has negative refractive power, wherein an object-side surface S3 thereof is concave, and an image-side surface S4 thereof is convex;

the third lens element L3 has positive refractive power, and both an object-side surface S5 and an image-side surface S6 thereof are convex;

the fourth lens element L4 has positive refractive power, wherein an object-side surface S7 thereof is concave, and an image-side surface S8 thereof is convex;

the fifth lens element L5 has positive refractive power, and both an object-side surface S9 and an image-side surface S10 thereof are convex;

The sixth lens element L6 has negative refractive power, and an object-side surface S10 and an image-side surface S11 thereof are concave;

The fifth lens element L5 and the sixth lens element L6 form a cemented lens assembly, i.e., the cemented surface between the image side surface of the fifth lens element L5 and the object side surface of the sixth lens element L6 is S10;

The seventh lens element L7 with positive refractive power has a convex object-side surface S12 and a concave image-side surface S13;

the object side surface S14 and the image side surface S15 of the optical filter G1 are planes;

The object side surface S16 and the image side surface S17 of the protective glass G2 are planes;

The imaging surface S18 is a plane.

The first lens L1, the third lens L3, the fifth lens L5, and the sixth lens L6 are glass spherical lenses, and the second lens L2, the fourth lens L4, and the seventh lens L7 are glass aspherical lenses.

The relevant parameters of each lens in the optical lens 100 in embodiment 1 are shown in table 1-1.

TABLE 1-1

The surface profile parameters of the aspherical lens of the optical lens 100 in example 1 are shown in tables 1-2.

TABLE 1-2

In the present embodiment, the field curvature curve, the F-Tan θ distortion curve, the vertical axis chromatic aberration curve, the axial aberration curve, the MTF curve, and the relative illuminance curve of the optical lens 100 are shown in fig. 2,3, 4, 5,6, and 7, respectively.

Fig. 2 shows a field curve of example 1, which indicates the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, the horizontal axis indicates the amount of shift (unit: mm), and the vertical axis indicates the half angle of view (unit: °). From the graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within-0.03 mm to 0.02mm, which indicates that the optical lens can well correct the field curvature.

Fig. 3 shows the F-Tan θ distortion curve of example 1, which represents the F-Tan θ distortion of light rays of different wavelengths at different image heights on the imaging plane, the horizontal axis represents the F-Tan θ distortion value (unit:%) and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within-50% -0, the image compression of the edge angle area is gentle, and the definition of the unfolded image is effectively improved.

Fig. 4 shows a vertical axis color difference graph of example 1, which represents color differences at different image heights on an imaging plane for each wavelength with respect to a center wavelength (0.546 μm), and the horizontal axis represents vertical axis color difference values (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis represents normalized field angle. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0-6 mu m, which shows that the optical lens can excellently correct chromatic aberration of the marginal view field and the secondary spectrum of the whole image surface.

Fig. 5 shows an axial aberration diagram of example 1, which represents aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents an axial aberration value (unit: mm), and the vertical axis represents a normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within +/-0.02 mm, which indicates that the optical lens can better correct the axial aberration.

Fig. 6 shows an MTF (modulation transfer function) graph of example 1, which represents the lens imaging modulation degree of different spatial frequencies at each view field, the horizontal axis represents the spatial frequency (unit: lp/mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF values of the embodiment are above 0.45 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 of the field of view from the center to the edge, and the MTF image has better imaging quality and better detail resolution under the conditions of low frequency and high frequency.

Fig. 7 shows the relative illuminance curve of example 1, which represents the relative illuminance values for different field angles on the imaging plane, the horizontal axis represents the half field angle (in: °), and the vertical axis represents the relative illuminance (in:%). As can be seen from the figure, the relative illuminance value of the optical lens is still greater than 95% at the maximum half field angle, which indicates that the optical lens has better relative illuminance.

Example 2

Referring to fig. 8, a schematic structural diagram of an optical lens 200 provided in embodiment 2 of the present invention is shown, and the main difference between the present embodiment and embodiment 1 is that: the optical parameters such as the radius of curvature and the lens thickness are different for each lens surface.

The relevant parameters of each lens in the optical lens 200 in example 2 are shown in table 2-1.

TABLE 2-1

The surface profile parameters of the aspherical lens of the optical lens 200 in example 2 are shown in table 2-2.

TABLE 2-2

In the present embodiment, the field curvature curve, the F-Tan θ distortion curve, the vertical axis chromatic aberration curve, the axial aberration curve, the MTF curve, and the relative illuminance curve of the optical lens 200 are shown in fig. 9, 10, 11, 12, 13, and 14, respectively. As can be seen from fig. 9, the curvature of field of the meridional image plane and the sagittal image plane are controlled within-0.04 mm to 0.02mm, which means that the optical lens 200 can well correct curvature of field. As can be seen from fig. 10, the F-Tan θ distortion of the optical lens 200 is controlled within-55% -0, and the image compression in the edge angle area is gentle, so that the definition of the unfolded image is effectively improved. As can be seen from fig. 11, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0-5 μm, which indicates that the optical lens 200 can excellently correct chromatic aberration of the fringe field and the secondary spectrum of the entire image plane. As can be seen from fig. 12, the axial aberration is controlled within-0.02 mm to 0.03mm, which means that the optical lens 200 can better correct the axial aberration. As can be seen from fig. 13, the MTF values of the present embodiment are all above 0.4 in the full 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 present embodiment has better imaging quality and better detail resolution under both low frequency and high frequency conditions. As can be seen from fig. 14, the relative illuminance value of the optical lens 200 is still greater than 80% at the maximum half angle of view, which indicates that the optical lens 200 has a better relative illuminance.

Example 3

Referring to fig. 15, a schematic structural diagram of an optical lens 300 provided in embodiment 3 of the present invention is shown, and the main difference between the present embodiment and embodiment 1 is that: the optical parameters such as the radius of curvature and the lens thickness are different for each lens surface.

The relevant parameters of each lens in the optical lens 300 in example 3 are shown in table 3-1.

TABLE 3-1

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The surface profile parameters of the aspherical lens of the optical lens 300 in example 3 are shown in table 3-2.

TABLE 3-2

In the present embodiment, the field curvature curve, the F-Tan θ distortion curve, the vertical axis chromatic aberration curve, the axial aberration curve, the MTF curve, and the relative illuminance curve of the optical lens 300 are shown in fig. 16, 17, 18, 19, 20, and 21, respectively. As can be seen from fig. 16, the curvature of field of the meridional image plane and the sagittal image plane is controlled within ±0.03mm, which means that the optical lens 300 can satisfactorily correct curvature of field. As can be seen from fig. 17, the F-Tan θ distortion of the optical lens 300 is controlled within-55% -0, the image compression in the edge angle area is gentle, and the definition of the unfolded image is effectively improved. As can be seen from fig. 18, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within 0-6 μm, which indicates that the optical lens 300 can excellently correct chromatic aberration of the fringe field and the secondary spectrum of the entire image plane. As can be seen from fig. 19, the axial aberration is controlled within-0.01 mm to 0.03mm, which means that the optical lens 300 can correct the axial aberration well. As can be seen from fig. 20, the MTF values of the present embodiment are all above 0.3 in the full 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 present embodiment has better imaging quality and better detail resolution under both low frequency and high frequency conditions. As can be seen from fig. 21, the relative illuminance value of the optical lens 300 at the maximum half angle of view is still greater than 85%, which indicates that the optical lens 300 has a better relative illuminance.

Referring to table 4, the optical characteristics corresponding to the above embodiments include the effective focal length f, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field angle, the maximum field angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

TABLE 4 Table 4

In summary, the optical lens provided by the present invention adopts seven lenses with specific focal power, and through specific surface shape collocation and reasonable focal power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, the imaging quality of the optical lens can be improved, and the lens has one or more advantages of large aperture, large field angle, high imaging quality, etc.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., 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 present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. 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 foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. An optical lens comprising seven lenses in total, in order from an object side to an imaging surface along an optical axis, comprising:

2. The optical lens according to claim 1, wherein an effective focal length f of the optical lens and a back focal length BFL of the optical lens satisfy: 0.6< BFL/f <0.8.

3. The optical lens according to claim 1, wherein a maximum field angle FOV of the optical lens, an effective focal length f of the optical lens, and a real image height IH corresponding to the maximum field angle of the optical lens satisfy: 60 ° < (fov×f)/IH <70 °.

4. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f2 of the second lens satisfy: -10< f2/f < -6.

5. The optical lens of claim 1, wherein a combined focal length f123 of the first lens, the second lens, and the third lens and a combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: 1.5< f123/f4567<2.1.

6. The optical lens of claim 1, wherein an object-side radius of curvature R7 of the fourth lens and an image-side radius of curvature R8 of the fourth lens satisfy: 0.8< (R7-R8)/(R7+R8) <1.

7. The optical lens system according to claim 1, wherein the object-side light-transmitting half-aperture d7 of the fourth lens element and the object-side light-transmitting half-aperture Sag7 of the fourth lens element satisfy: -0.09< Sag7/d7< -0.01.

8. The optical lens of claim 1, wherein an object-side radius of curvature R1 of the first lens, an image-side radius of curvature R2 of the first lens, and a center thickness CT1 of the first lens satisfy: 5.8< R1/(R2+CT1) <18.8.

9. The optical lens of claim 1, wherein the object-side light passing half aperture d1 of the first lens, the real image height ih corresponding to the maximum half field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 0.8< d1/ih/tan (FOV/2) <1.1.

10. The optical lens system according to claim 1, wherein an image-side light-transmitting half-diameter d6 of the third lens element and an object-side light-transmitting half-diameter d7 of the fourth lens element satisfy: 1.6< d6/d7<2.2.