CN117310949A

CN117310949A - Optical lens

Info

Publication number: CN117310949A
Application number: CN202310557889.2A
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: 2023-05-18
Filing date: 2023-05-18
Publication date: 2023-12-29

Abstract

The invention provides an optical lens, which comprises seven lenses in sequence from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a concave object side surface and a concave image side surface; a second lens having positive optical power; a third lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a fourth lens with positive focal power, the object side surface of which is a convex surface; a fifth lens having negative optical power; a sixth lens having positive optical power; a seventh lens element with negative refractive power having an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region; the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.0 < IH/EPD < 3.5. The optical lens provided by the invention has the advantages of large view field, 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 the intellectualization of automobiles, the driving assistance function of the automobiles is gradually enhanced, wherein the visual information acquisition is a core tool. Along with the improvement of the automatic driving level, the requirements on the vehicle-mounted camera are gradually increased, and especially the front-mounted camera is improved. The front camera can enhance active safety and driver auxiliary functions, such as Automatic Emergency Braking (AEB), adaptive Cruise Control (ACC), lane Keeping Auxiliary System (LKAS), traffic Jam Auxiliary (TJA) and the like, and has the defects of large number of lenses, overlong total optical length and the like while meeting the advantages of high resolution, large field angle, good environmental adaptability and the like, and is unfavorable for miniaturization of an electronic system.

Disclosure of Invention

In view of the foregoing, it is an object of the present invention to provide an optical lens capable of solving one or more of the above-mentioned problems.

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

an optical lens comprises seven lenses in sequence from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a concave object side surface and a concave image side surface; a second lens having positive optical power; a third lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a fourth lens with positive focal power, the object side surface of which is a convex surface; a fifth lens having negative optical power; a sixth lens having positive optical power; a seventh lens element with negative refractive power having an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region; the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.0 < IH/EPD < 3.5.

In some embodiments, the second lens element has a concave object-side surface and a convex image-side surface.

In some embodiments, the second lens element has a convex object-side surface and a concave image-side surface.

In some embodiments, the fourth lens element has a convex object-side surface and a convex image-side surface.

In some embodiments, the fifth lens element has a concave object-side surface and a concave image-side surface.

In some embodiments, the object side surface of the sixth lens is convex.

In some embodiments, the image side of the sixth lens is concave.

In some embodiments, the image side of the sixth lens is convex.

In some embodiments, the fourth lens and the fifth lens are cemented to form a cemented lens.

In some embodiments, the fourth lens, the fifth lens, and the sixth lens are cemented to form a cemented lens.

In some embodiments, the second and seventh lenses have aspherical mirror surfaces.

In some embodiments, a stop is further disposed between the second lens and the third lens.

In some embodiments, a stop is also disposed between the first lens and the second lens.

In some embodiments, the maximum field angle FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 85 DEG < FOV/FNO.

In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 3.2 < TTL/IH < 3.5.

In some embodiments, the optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: TTL/f is less than 6.2 and less than 6.8.

In some embodiments, the real image height IH corresponding to the effective aperture D1 of the first lens object side and the maximum field angle of the optical lens and the maximum half field angle θ of the optical lens satisfy: 0.4 < D1/IH/tan (θ) < 0.6.

In some embodiments, the sum of the optical total length TTL of the optical lens and the center thickness CT4 of the fourth lens, the center thickness CT5 of the fifth lens, the center thickness CT6 of the sixth lens satisfies: 0.1 < (CT4+CT5+CT6)/TTL < 0.3.

In some embodiments, the effective focal length f of the optical lens and the radius of curvature R1 of the first lens object-side surface satisfy: r1/f < -15.0.

In some embodiments, the optical back focal length BFL of the optical lens and the optical total length TTL of the optical lens satisfy: BFL/TTL is more than 0.05 and less than 0.12.

In some embodiments, the effective focal length f of the optical lens and the effective focal length f1 of the first lens satisfy: -2.0 < f1/f < -1.0.

In some embodiments, the effective focal length f of the optical lens and the effective focal length f2 of the second lens satisfy: 2.3 < f2/f < 8.0.

In some embodiments, the effective focal length f of the optical lens and the effective focal length f3 of the third lens satisfy: 2.0 < f3/f < 3.0.

Compared with the prior art, the invention has the beneficial effects that: the lens shape and the focal power combination among the lenses are reasonably matched, so that the effects of large view field, large aperture and miniaturization are realized.

Drawings

Fig. 1 is a schematic structural diagram of an optical lens according to 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 the relative illuminance of the optical lens in embodiment 1 of the present invention.

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

Fig. 7 is a schematic structural diagram of an optical lens according to embodiment 2 of the present invention.

Fig. 8 is a graph showing the field curvature of the optical lens in embodiment 2 of the present invention.

Fig. 9 is a graph showing the relative illuminance of the optical lens in embodiment 2 of the present invention.

Fig. 10 is an MTF graph of the optical lens in example 2 of the present invention.

Fig. 11 is an axial aberration diagram of an optical lens in embodiment 2 of the present invention.

Fig. 12 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 2 of the present invention.

Fig. 13 is a schematic structural diagram of an optical lens in embodiment 3 of the present invention.

Fig. 14 is a graph showing the field curvature of the optical lens in embodiment 3 of the present invention.

Fig. 15 is a graph showing the relative illuminance of the optical lens in embodiment 3 of the present invention.

Fig. 16 is an MTF graph of an optical lens in example 3 of the present invention.

Fig. 17 is an axial aberration diagram of an optical lens in embodiment 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 a schematic structural diagram of an optical lens in embodiment 4 of the present invention.

Fig. 20 is a graph showing the field curvature of an optical lens in embodiment 4 of the present invention.

Fig. 21 is a graph showing the relative illuminance of the optical lens in embodiment 4 of the present invention.

Fig. 22 is an MTF graph of the optical lens in example 4 of the present invention.

Fig. 23 is an axial aberration diagram of the optical lens in embodiment 4 of the present invention.

Fig. 24 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 4 of the present invention.

Fig. 25 is a schematic structural diagram of an optical lens in embodiment 5 of the present invention.

Fig. 26 is a graph showing the field curvature of an optical lens in embodiment 5 of the present invention.

Fig. 27 is a graph showing the relative illuminance of the optical lens in embodiment 5 of the present invention.

Fig. 28 is an MTF graph of an optical lens in example 5 of the present invention.

Fig. 29 is an axial aberration diagram of an optical lens according to embodiment 5 of the present invention.

Fig. 30 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 5 of the present invention.

Detailed Description

For a better understanding of the invention, various aspects of the invention 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 invention and are not intended to limit the scope of the invention 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 invention, use of "may" means "one or more embodiments of the invention. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention 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 invention and features of the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.

The embodiment of the invention provides an optical lens, which sequentially comprises from an object side to an image side: the optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an optical filter and protective glass.

The first lens has negative focal power, and the object side surface of the first lens is a concave surface and the image side surface of the first lens is a concave surface; the second lens has positive focal power, the object side surface of the second lens is a convex surface or a concave surface, and the image side surface of the second lens is a concave surface or a convex surface; the third lens has positive focal power, and the object side surface of the third lens is a convex surface and the image side surface of the third lens is a convex surface; the fourth lens has positive focal power, and the object side surface of the fourth lens is a convex surface and the image side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface; the sixth lens is provided with positive focal power, the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface or a concave surface; the seventh lens has negative focal power, and the object side surface of the seventh lens is a convex surface and the image side surface of the seventh lens is a concave surface.

In some embodiments, the fourth lens and the fifth lens may be cemented to form a cemented lens, or the fourth lens, the fifth lens and the sixth lens may be cemented to form a cemented lens, so as to share chromatic aberration correction of the optical lens, improve resolution of the optical lens, and make the optical lens compact in structure, thereby being beneficial to achieving miniaturization of the optical lens.

In some embodiments, a diaphragm may be disposed between the second lens and the third lens and may be disposed near the object side of the third lens, or a diaphragm may be disposed between the first lens and the second lens and may be disposed near the object side of the second lens, so as to converge the range of light rays emitted from the front end of the optical lens, and reduce the rear end caliber of the optical lens.

In some embodiments, the aperture value FNO of the optical lens satisfies: FNO is not less than 1.60. The range is satisfied, the large aperture characteristic is realized, and the definition of the image can be ensured in a low-light environment or at night.

In some embodiments, the maximum half field angle θ of the optical lens satisfies: 65 DEG < theta. The wide-angle characteristic can be realized by meeting the range, so that more scene information can be acquired, and the requirement of large-range detection is met.

In some embodiments, the incidence angle CRA of the maximum field angle chief ray of the optical lens on the image plane satisfies: 10 DEG < CRA < 30 deg. The above range is satisfied, so that a larger tolerance error range exists between the CRA of the optical lens and the CRA of the chip photosensitive element, and the adaptation capability of the optical lens to the image sensor is improved.

In some embodiments, the real image height IH and the entrance pupil diameter EPD corresponding to the maximum field angle of the optical lens satisfy: 3.0 < IH/EPD < 3.5. The range is satisfied, so that the width of a light beam emitted into the optical lens by the optical lens under the premise of different view angles is as large as possible, the brightness of the optical lens at an image plane is improved, the generation of a dark angle is avoided, and the imaging area of the optical lens is increased.

In some embodiments, the maximum field angle FOV and aperture value FNO of the optical lens satisfy: 85 DEG < FOV/FNO. The above range is satisfied, which is advantageous to expand the angle of view of the optical lens and increase the aperture of the optical lens, realizing the characteristics of wide angle and large aperture. The realization of the wide-angle characteristic is favorable for the optical lens to acquire more scene information, meets the requirement of large-range detection, and is favorable for improving the problem of rapid decrease of the relative brightness of the edge view field caused by the wide angle, thereby being favorable for acquiring more scene information.

In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 3.2 < TTL/IH < 3.5. The above range is satisfied, which is beneficial to balancing the total length and imaging quality of the optical lens.

In some embodiments, the optical total length TTL and the effective focal length f of the optical lens satisfy: TTL/f is less than 6.2 and less than 6.8. The length and the volume of the optical lens can be effectively limited by meeting the above range, and the miniaturization of the optical lens can be realized.

In some embodiments, the effective aperture D1 of the first lens object-side surface and the real image height IH and the maximum half field angle θ corresponding to the maximum field angle satisfy: 0.4 < D1/IH/tan (θ) < 0.6. The optical lens meets the range, is beneficial to reducing the front end caliber of the optical lens and realizes the miniaturization of the optical lens.

In some embodiments, the sum of the total optical length TTL of the optical lens and the center thickness CT4 of the fourth lens, the center thickness CT5 of the fifth lens, the center thickness CT6 of the sixth lens satisfies: 0.1 < (CT4+CT5+CT6)/TTL < 0.3. The light source device meets the above range, can make the structure of the optical lens compact, is beneficial to realizing miniaturization of the optical lens, can make light stably enter, and improves the illuminance of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the first lens object-side radius of curvature R1 satisfy: r1/f < -15.0. The range is satisfied, the surface curvature of the object side surface of the first lens can be effectively controlled, the angle of view is increased, and the front end caliber of the optical lens is controlled.

In some embodiments, the optical back focal length BFL and the optical total length TTL of the optical lens satisfy: BFL/TTL is more than 0.05 and less than 0.12. The optical lens has larger optical back focus, thereby being beneficial to reducing interference between the lens and the imaging chip and reducing the correction difficulty of CRA.

In some embodiments, the effective focal length f of the optical lens and the effective focal length f1 of the first lens satisfy: -2.0 < f1/f < -1.0. The range is satisfied, so that the first lens has proper negative focal power, the refraction angle change of incident light is mild, excessive aberration caused by excessively strong refraction angle change is avoided, more light rays enter the rear optical system, the illuminance is increased, 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 f2 of the second lens satisfy: 2.3 < f2/f < 8.0. The optical lens has the advantages that the range is met, the second lens can have proper positive focal power, off-axis aberration caused by the first lens can be corrected by reasonably limiting the focal power of the second lens, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the effective focal length f3 of the third lens satisfy: 2.0 < f3/f < 3.0. The range is satisfied, so that the third lens has proper positive focal power, smooth transition of light trend is facilitated, and imaging quality of the optical lens is improved.

For better optical performance of the system, a plurality of aspheric lenses are adopted in the lens, and the shape of each aspheric surface of the optical lens meets 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, and A, B, C, D, E, F is the second, fourth, sixth, eighth, tenth 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 provided in embodiment 1 of the present invention is shown, where the optical lens sequentially includes, along an optical axis from an object side to an imaging surface S18: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.

The first lens element L1 has a negative refractive power, wherein an object-side surface S1 thereof is a concave surface, and an image-side surface S2 thereof is a concave surface; the second lens element L2 has positive 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, wherein an object-side surface S5 thereof is convex, and an image-side surface S6 thereof is convex; the fourth lens element L4 has positive refractive power, wherein an object-side surface S7 thereof is convex, and an image-side surface thereof is convex; the fifth lens element L5 has negative refractive power, wherein the object-side surface thereof is concave, the image-side surface S9 is concave, and the fourth lens element L4 and the fifth lens element L5 are cemented together to form a cemented lens, and the cemented surface thereof is S8; the sixth lens element L6 with positive refractive power has a convex object-side surface S10 and a concave image-side surface S11; the seventh lens element L7 with negative refractive power has a convex object-side surface S12 at a paraxial region and a concave image-side surface S13 at a paraxial region; the optical filter G1, the object side surface S14 and the image side surface S15 of which are plane surfaces; the cover glass G2 has a planar object side surface S16 and an image side surface S17.

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

TABLE 1-1

The curve coefficients of the aspherical lenses of the optical lenses in example 1 are shown in tables 1 to 2.

TABLE 1-2

Fig. 2 shows a field curvature graph of example 1, in which the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane is represented by the horizontal axis representing the amount of shift (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridian image plane and the sagittal image plane are controlled within +/-0.025 mm, which indicates that the optical lens can excellently correct the field curvature.

Fig. 3 shows a graph of relative illuminance for example 1, which represents relative illuminance values for different field angles on an imaging plane, with the horizontal axis representing half field angle (in: °), and the vertical axis representing relative illuminance (in:%). 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 excellent relative illuminance.

Fig. 4 shows a Modulation Transfer Function (MTF) graph of example 1, which represents a lens imaging modulation degree representing different spatial frequencies at each view field, the horizontal axis represents spatial frequency (unit: lp/mm), and the vertical axis represents MTF value. As can be seen from the graph, the MTF values of the present embodiment are all above 0.4 in the full field of view, in the range of 0 to 160lp/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 good imaging quality and good detail resolution at both low frequency and high frequency.

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: μm), and the vertical axis represents a normalized pupil radius. As can be seen from the figure, the axial aberration is controlled within ±10μm, which means that the optical lens can correct axial aberration well.

Fig. 6 shows a vertical axis color difference graph of example 1, which shows color differences at different image heights on an imaging plane for each wavelength with respect to a center wavelength (0.55 μm), with the horizontal axis showing a vertical axis color difference value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis showing a 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 +/-1.5 mu m, which shows that the optical lens can excellently correct chromatic aberration of the edge view field and the secondary spectrum of the whole image surface.

Example 2

Referring to fig. 7, a schematic structural diagram of an optical lens provided in embodiment 2 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging surface S18 along an optical axis: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.

The first lens element L1 has a negative refractive power, wherein an object-side surface S1 thereof is a concave surface, and an image-side surface S2 thereof is a concave surface; the second lens element L2 has positive 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, wherein an object-side surface S5 thereof is convex, and an image-side surface S6 thereof is convex; the fourth lens element L4 has positive refractive power, wherein an object-side surface S7 thereof is convex, and an image-side surface thereof is convex; the fifth lens element L5 has negative refractive power, wherein the object-side surface thereof is concave, the image-side surface S9 is concave, and the fourth lens element L4 and the fifth lens element L5 are cemented together to form a cemented lens, and the cemented surface thereof is S8; the sixth lens element L6 with positive refractive power has a convex object-side surface S10 and a convex image-side surface S11; the seventh lens element L7 with negative refractive power has a convex object-side surface S12 at a paraxial region and a concave image-side surface S13 at a paraxial region; the optical filter G1, the object side surface S14 and the image side surface S15 of which are plane surfaces; the cover glass G2 has a planar object side surface S16 and an image side surface S17.

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

TABLE 2-1

The curve coefficients of the aspherical lenses of the optical lenses in example 2 are shown in tables 2-2.

TABLE 2-2

Fig. 8 to 12 show a field curve graph, a relative illuminance graph, a Modulation Transfer Function (MTF) graph, an axial aberration graph, and a vertical axis aberration graph of example 2, respectively. As can be seen from the graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within +/-0.025 mm, which indicates that the optical lens can excellently correct the field curvature; the relative illuminance value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens has excellent relative illuminance; the MTF value of the optical lens is above 0.45 in the whole view field, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process of viewing the field from the center to the edge, and the optical lens has good imaging quality and good detail resolution under the conditions of low frequency and high frequency; the offset of the axial aberration is controlled within +/-17 mu m, which indicates that the optical lens can well correct the axial aberration; the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-1.5 mu m, which shows that the optical lens can excellently correct chromatic aberration of the edge view field and the secondary spectrum of the whole image surface.

Example 3

Referring to fig. 13, a schematic structural diagram of an optical lens provided in embodiment 3 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging surface S18 along an optical axis: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.

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

TABLE 3-1

The curve coefficients of the aspherical lenses of the optical lenses in example 3 are shown in tables 3-2.

TABLE 3-2

Fig. 14 to 18 show a field curve graph, a relative illuminance graph, a Modulation Transfer Function (MTF) graph, an axial aberration graph, and a vertical axis aberration graph of example 3, respectively. As can be seen from the graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within +/-0.03 mm, which indicates that the optical lens can excellently correct the field curvature; the relative illuminance value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens has excellent relative illuminance; the MTF value of the optical lens is above 0.4 in the whole view field, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process of viewing the field from the center to the edge, and the optical lens has good imaging quality and good detail resolution under the conditions of low frequency and high frequency; the offset of the axial aberration is controlled within +/-15 mu m, which indicates that the optical lens can well correct the axial aberration; the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-3.2 mu m, which shows that the optical lens can excellently correct chromatic aberration of the edge view field and the secondary spectrum of the whole image surface.

Example 4

Referring to fig. 19, a schematic structural diagram of an optical lens provided in embodiment 4 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging surface S17 along an optical axis: a first lens L1, a second lens L2, a stop ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.

The first lens element L1 has a negative refractive power, wherein an object-side surface S1 thereof is a concave surface, and an image-side surface S2 thereof is a concave surface; the second lens element L2 has positive 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, wherein an object-side surface S5 thereof is convex, and an image-side surface S6 thereof is convex; the fourth lens element L4 has positive refractive power, wherein an object-side surface S7 thereof is convex, and an image-side surface thereof is convex; the fifth lens element L5 has negative refractive power, wherein an object-side surface thereof is concave, and an image-side surface thereof is concave; the sixth lens element L6 has positive refractive power, wherein the object-side surface thereof is convex, the image-side surface S10 thereof is convex, the fourth lens element L4, the fifth lens element L5 and the sixth lens element L6 are cemented together to form a cemented lens, the cemented surface between the fourth lens element L4 and the fifth lens element L5 is S8, and the cemented surface between the fifth lens element L5 and the sixth lens element L6 is S9; the seventh lens element L7 with negative refractive power has a convex object-side surface S11 at a paraxial region and a concave image-side surface S12 at a paraxial region; the optical filter G1, the object side surface S13 and the image side surface S14 of which are plane surfaces; the object side surface S15 and the image side surface S16 of the cover glass G2 are both flat surfaces.

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

TABLE 4-1

The curve coefficients of the aspherical lenses of the optical lenses in example 4 are shown in tables 4-2.

TABLE 4-2

Fig. 20 to 24 show a field curve graph, a relative illuminance graph, a Modulation Transfer Function (MTF) graph, an axial aberration graph, and a vertical axis aberration graph of example 4, respectively. As can be seen from the graph, the field curvature of the meridian image plane and the sagittal image plane are controlled within +/-0.022 mm, which shows that the optical lens can excellently correct the field curvature; the relative illuminance value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens has excellent relative illuminance; the MTF value of the optical lens is above 0.45 in the whole view field, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process of viewing the field from the center to the edge, and the optical lens has good imaging quality and good detail resolution under the conditions of low frequency and high frequency; the offset of the axial aberration is controlled within +/-18 mu m, which indicates that the optical lens can well correct the axial aberration; the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-1.5 mu m, which shows that the optical lens can excellently correct chromatic aberration of the edge view field and the secondary spectrum of the whole image surface.

Example 5

Referring to fig. 25, a schematic structural diagram of an optical lens provided in embodiment 5 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging surface S17 along an optical axis: a first lens L1, a stop ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.

The first lens element L1 has a negative refractive power, wherein an object-side surface S1 thereof is a concave surface, and an image-side surface S2 thereof is a concave surface; the second lens element L2 has positive refractive power, wherein an object-side surface S3 thereof is convex, and an image-side surface S4 thereof is concave; the third lens element L3 has positive refractive power, wherein an object-side surface S5 thereof is convex, and an image-side surface S6 thereof is convex; the fourth lens element L4 has positive refractive power, wherein an object-side surface S7 thereof is convex, and an image-side surface thereof is convex; the fifth lens element L5 has negative refractive power, wherein an object-side surface thereof is concave, and an image-side surface thereof is concave; the sixth lens element L6 has positive refractive power, wherein an object-side surface thereof is convex, an image-side surface S10 thereof is concave at a paraxial region thereof, and the fourth lens element L4, the fifth lens element L5 and the sixth lens element L6 are cemented to form a cemented lens, the cemented surface between the fourth lens element L4 and the fifth lens element L5 is S8, and the cemented surface between the fifth lens element L5 and the sixth lens element L6 is S9; the seventh lens element L7 with negative refractive power has a convex object-side surface S11 at a paraxial region and a concave image-side surface S12 at a paraxial region; the optical filter G1, the object side surface S13 and the image side surface S14 of which are plane surfaces; the object side surface S15 and the image side surface S16 of the cover glass G2 are both flat surfaces.

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

TABLE 5-1

The curve coefficients of the aspherical lenses of the optical lenses in example 5 are shown in table 5-2.

TABLE 5-2

Fig. 26 to 30 show a field curve graph, a relative illuminance graph, a Modulation Transfer Function (MTF) graph, an axial aberration graph, and a vertical axis aberration graph of example 5, respectively. As can be seen from the figure, the field curvature of the meridian image plane and the sagittal image plane is controlled within +/-0.045 mm, which indicates that the optical lens can excellently correct the field curvature; the relative illuminance value of the optical lens is still greater than 80% at the maximum half field angle, which indicates that the optical lens has excellent relative illuminance; the MTF value of the optical lens is above 0.4 in the whole view field, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process of viewing the field from the center to the edge, and the optical lens has good imaging quality and good detail resolution under the conditions of low frequency and high frequency; the offset of the axial aberration is controlled within +/-15 mu m, which indicates that the optical lens can well correct the axial aberration; the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-1.5 mu m, which shows that the optical lens can excellently correct chromatic aberration of the edge view field and the secondary spectrum of the whole image surface.

Referring to table 6, the optical characteristics corresponding to the above embodiments include the effective focal length f, the maximum half field angle θ, the entrance pupil diameter EPD, the total optical length TTL, the aperture value FNO, the real image height IH, and the numerical values corresponding to each of the conditional expressions in the embodiments.

TABLE 6

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

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, seven lenses altogether, characterized in that, from the object side to the imaging plane along the optical axis, are:

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

a second lens having positive optical power;

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

a fourth lens having positive optical power;

a fifth lens having negative optical power;

a sixth lens having positive optical power;

a seventh lens element with negative refractive power having an object-side surface being convex at a paraxial region and an image-side surface being concave at a paraxial region;

the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 3.0 < IH/EPD < 3.5.

2. The optical lens according to claim 1, wherein a maximum field angle FOV of the optical lens and an aperture value FNO of the optical lens satisfy: 85 DEG < FOV/FNO.

3. The optical lens according to claim 1, wherein the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle of the optical lens satisfy: 3.2 < TTL/IH < 3.5.

4. The optical lens of claim 1, wherein an optical total length TTL of the optical lens and an effective focal length f of the optical lens satisfy: TTL/f is less than 6.2 and less than 6.8.

5. The optical lens system according to claim 1, wherein the effective aperture D1 of the first lens object side surface and the real image height IH corresponding to the maximum field angle of the optical lens system and the maximum half field angle θ of the optical lens system satisfy: 0.4 < D1/IH/tan (θ) < 0.6.

6. The optical lens of claim 1, wherein a sum of an optical total length TTL of the optical lens and a center thickness CT4 of the fourth lens, a center thickness CT5 of the fifth lens, and a center thickness CT6 of the sixth lens satisfies: 0.1 < (CT4+CT5+CT6)/TTL < 0.3.

7. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a radius of curvature R1 of the first lens object-side surface satisfy: r1/f < -15.0.

8. The optical lens of claim 1, wherein an optical back focal length, BFL, of the optical lens and an optical total length, TTL, of the optical lens satisfy: BFL/TTL is more than 0.05 and less than 0.12.

9. The optical lens of claim 1, wherein an effective focal length f of the optical lens and an effective focal length f1 of the first lens satisfy: -2.0 < f1/f < -1.0.

10. The optical lens of claim 1, wherein an effective focal length f of the optical lens and an effective focal length f3 of the third lens satisfy: 2.0 < f3/f < 3.0.