CN117970610B

CN117970610B - Optical lens

Info

Publication number: CN117970610B
Application number: CN202410369798.0A
Authority: CN
Inventors: 徐文; 赵志鹏; 章彬炜
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2024-03-29
Filing date: 2024-03-29
Publication date: 2024-06-11
Anticipated expiration: 2044-03-29
Also published as: CN117970610A

Abstract

The invention provides an optical lens, which comprises six lenses in sequence from an object side to an imaging surface along an optical axis: a first lens having negative optical power; a second lens element with positive refractive power having a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region; a third lens having positive optical power, the object side surface of which is a convex surface; 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 an object-side surface being concave at a paraxial region and an image-side surface being convex at a paraxial region; a sixth lens element with positive refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; the real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy the following conditions: 1.1< IH/f <2. The optical lens provided by the invention has the advantages of miniaturization, large aperture, large image plane, long focal length 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 development and application of the intelligent technology of the automobile, the application of the vehicle-mounted lens is also becoming wider and wider.

At present, the vehicle-mounted lens in the market mainly comprises an external lens, the internal lens is low in current but rapid in growth, and the vehicle-mounted lens applied to fatigue monitoring in the vehicle in the market is more conventional, has small aperture, long total length and blurred imaging at night, and is not beneficial to normal work in a dim environment in the vehicle.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an optical lens having advantages of large aperture, total length, night high definition imaging, etc.

The invention adopts the technical scheme that:

An optical lens comprising six lenses, in order from an object side to an imaging plane along an optical axis, comprising:

a first lens having negative optical power;

A second lens element with positive refractive power having a concave object-side surface at a paraxial region and a convex image-side surface at a paraxial region;

a third lens having positive optical power, the object side surface of which is a convex surface;

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 an object-side surface being concave at a paraxial region and an image-side surface being convex at a paraxial region;

a sixth lens element with positive refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region;

The real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.1< IH/f <2.

Further preferably, the effective focal length f of the optical lens and the aperture value Fno of the optical lens satisfy: 4mm < f/FNo <6mm.

Further preferably, the optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5< TTL/f <2.5.

Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -20< f1/f < -3.

Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 3< f2/f <7.

Further preferably, the object-side radius of curvature R3 of the second lens and the image-side radius of curvature R4 of the second lens satisfy: 1.1< R3/R4<2.

Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 10< f4/f <30.

Further preferably, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -5< f1/f2< -1.

Further preferably, a focal length f4 of the fourth lens and a focal length f5 of the fifth lens satisfy: 3< f4/f5<8.

Further preferably, the object-side effective aperture DM1 of the first lens and the object-side effective aperture DM3 of the third lens satisfy: 1< DM1/DM3<1.5; the object-side effective aperture DM3 of the third lens and the object-side effective aperture DM6 of the sixth lens satisfy: 0.6< DM3/DM6<0.8.

Further preferably, 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: 1.2< TTL/IH <1.8.

Compared with the prior art, the optical lens provided by the invention has the advantages that through specific surface shape setting and reasonable focal power distribution, the lens has the characteristic of long focus, larger local details can be better presented, and the picture is more concentrated and compact, so that the local shooting requirement is met; the large image surface characteristic of the lens can be realized, and the chip with larger size can be mounted, so that the high-definition imaging of the lens can be realized. In addition, the optical lens has a compact large aperture structure, so that the overall length of the optical lens is effectively shortened, more luminous flux can enter the optical lens, and the system can image clearly in a dim environment; meanwhile, the working wave band of the optical lens is in an infrared wave band, so that the infrared light source can be assisted to effectively improve the night imaging quality.

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 an axial chromatic aberration diagram of an optical lens in embodiment 1 of the present invention.

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

Fig. 6 is a schematic structural diagram of an optical lens in embodiment 2 of the present invention.

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

FIG. 8 is a graph showing F-Tanθ distortion of an optical lens in example 2 of the present invention.

Fig. 9 is an axial chromatic aberration diagram of an optical lens in embodiment 2 of the present invention.

Fig. 10 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 2 of the present invention.

Fig. 11 is a schematic structural diagram of an optical lens in embodiment 3 of the present invention.

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

FIG. 13 is a graph showing F-Tanθ distortion of an optical lens in example 3 of the present invention.

Fig. 14 is an axial chromatic aberration diagram of an optical lens in embodiment 3 of the present invention.

Fig. 15 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 3 of the present invention.

Fig. 16 is a schematic structural diagram of an optical lens in embodiment 4 of the present invention.

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

FIG. 18 is a graph showing F-Tanθ distortion of an optical lens in example 4 of the present invention.

Fig. 19 is a graph showing axial chromatic aberration of an optical lens in embodiment 4 of the present invention.

Fig. 20 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 4 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 six lenses, and the six lenses are a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth 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. The second lens element may have positive optical power, with an object-side surface being concave at a paraxial region and an image-side surface being convex at a paraxial region. The third lens may have positive optical power, and an object side surface thereof is 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 refractive power, wherein an object-side surface thereof is concave at a paraxial region thereof and an image-side surface thereof is convex at a paraxial region thereof. The sixth lens element may have positive refractive power, wherein an object-side surface thereof is convex at a paraxial region and an image-side surface thereof is concave at a paraxial region.

In some embodiments, the optical lens may further include a diaphragm for limiting the light beam, and the diaphragm may be located between the second lens and the third lens, so as to reduce the generation of ghost images of the optical lens, and effectively reduce the difficulty in distortion correction of the lens.

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 sixth 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, 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 real image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.1< IH/f <2. The lens can realize the long focal length characteristic of the lens, thereby meeting the local shooting requirement, realizing the large image surface characteristic of the lens, carrying a chip with larger size and realizing the high-definition imaging of the lens.

In some embodiments, the effective focal length f of the optical lens and the aperture value Fno of the optical lens satisfy: 4mm < f/FNo <6mm. The system meets the conditions, is favorable for high-definition imaging of the system in a dim environment, and well realizes the balance of the large aperture and the long focal length of the lens.

In some embodiments, the optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.5< TTL/f <2.5. The length of the lens can be effectively limited by meeting the above conditions, and the miniaturization of the optical lens can be realized.

In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -20< f1/f < -3. The working caliber of the first lens can be balanced with the relation between the size of the image surface and the angle of view, so that the lens has a smaller caliber and a larger image surface can be realized.

In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 3< f2/f <7. The optical lens can enable light rays to be stable in trend, is favorable for balancing aberration caused by negative refractive power of the first lens, effectively corrects edge aberration of the optical lens, and improves imaging resolution.

In some embodiments, the object-side radius of curvature R3 of the second lens and the image-side radius of curvature R4 of the second lens satisfy: 1.1< R3/R4<2. The conditions are met, the meniscus shape of the second lens is reasonably arranged, so that the convergence of light is facilitated, the aberration caused by the first lens is balanced, the difficulty of distortion correction is reduced, the image of the lens in the marginal view field is not distorted, and the imaging quality of the optical system is improved.

In some embodiments, the effective focal length f of the optical lens and the object-side radius of curvature R3 of the second lens satisfy: -2< R3/f < -0.2. The effective focal length f of the optical lens and the image-side curvature radius R4 of the second lens satisfy: -1< R4/f < -0.1. The conditions are met, the meniscus shape of the second lens is reasonably arranged, so that the convergence of light is facilitated, the aberration caused by the first lens is balanced, the difficulty of distortion correction is reduced, the image of the lens in the marginal view field is not distorted, and the imaging quality of the optical system is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 10< f4/f <30. The object-side radius of curvature R7 of the fourth lens element and the image-side radius of curvature R8 of the fourth lens element satisfy: 0.8< R7/R8<2. The optical power and the surface shape of the fourth lens are reasonably set, so that smooth transition of light is facilitated, various aberrations generated by the fourth lens are balanced, and the imaging quality of the optical system is improved.

In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -5< f1/f2< -1. The above conditions are satisfied, and the focal length ratio of the first lens and the second lens is reasonably set, so that the aberration caused by the negative refractive power of the first lens is balanced, the edge aberration of the optical lens is corrected, and the imaging resolution is improved.

In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 3< f4/f5<8. The above conditions are met, and the focal length ratio of the fourth lens and the fifth lens is reasonably set, so that the on-axis aberration of the optical lens can be corrected, and the imaging quality of the optical lens can be improved; meanwhile, the angle of the ghost light rays between the fourth lens and the fifth lens can be improved, and the ghost energy is reduced.

In some embodiments, the object-side effective aperture DM1 of the first lens and the object-side effective aperture DM3 of the third lens satisfy: 1< DM1/DM3<1.5; the object-side effective aperture DM3 of the third lens element and the object-side effective aperture DM6 of the sixth lens element satisfy: 0.6< DM3/DM6<0.8. The system meets the conditions, is beneficial to improving the light quantity of the system and reducing the loss of light entering and exiting the system, so that the system can improve the response rate of the system while imaging in a high-definition environment with low light level or even in a dim environment, and the large aperture imaging effect of the lens is better realized.

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: 1.2< TTL/IH <1.8. The optical lens has the advantages that the ratio of the total optical length to the image height of the optical lens is reasonably limited, the total optical length can be shortened while large target surface imaging is realized, miniaturization of the optical lens and balance of large target surface imaging are realized, and market competitiveness is improved.

In some embodiments, the effective focal length f, the maximum field angle FOV, and the image height IH of the optical lens corresponding to the maximum field angle satisfy: 40 ° < (f×fov)/IH <55 °. The method meets the conditions, and is favorable for realizing the equilibrium of long focus and large target surface imaging of the optical lens by reasonably limiting the relation among the focal length, the field angle and the image height of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1< f3/f <2. The third lens element can have a larger positive refractive power, which is beneficial to accelerating the deflection trend of light rays and promoting the miniaturization of the structure of the optical lens element.

In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 4< f5/f <10. The object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: 0.5< R9/R10<1.5. The light beam converging device meets the conditions, is favorable for further converging the light beam, reduces the included angle between the principal ray of the edge view field and the optical axis, and reduces the diameter of a light spot to improve aberration; meanwhile, the imaging area of the optical lens can be 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 f6 of the sixth lens satisfy: 2.5< f6/f <50. The object-side radius of curvature R11 of the sixth lens and the image-side radius of curvature R12 of the sixth lens satisfy: 0.8< R11/R12<1.5. The shape of the sixth lens is adjusted to bear corresponding positive focal power, so that light deflection can be accelerated, the focusing height of light can be improved, the photosensitive area of an image surface can be increased, and the imaging quality of the optical lens can be effectively improved.

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: -8< R7/f < -0.5; the effective focal length f of the optical lens and the image-side curvature radius R8 of the fourth lens satisfy: -8< R8/f < -0.5. The lens meets the conditions, is favorable for balancing various aberrations of the lens, improves the imaging quality of the optical lens, reduces the processing difficulty of the fourth lens and improves the processability.

In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth 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 as to reduce the number of lenses and reduce the size of the lenses, and better achieve miniaturization of the lens. More specifically, the first lens and the third lens of the present invention may be spherical lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens may be aspherical lenses.

In some embodiments, the lens material in the optical lens provided by the present invention may be glass or plastic. When the lens is made of plastic, the production cost can be effectively reduced. In addition, when the lens is made of glass, the geometrical chromatic aberration of the optical system can be effectively corrected through the characteristic of low chromatic dispersion of the glass. The optical lens provided by the invention at least comprises one glass lens and one plastic lens, and six lenses are adopted for glass-plastic mixing and matching, so that the optical lens has good thermal stability on the premise of meeting high pixels, and the cost can be reduced. More specifically, the first lens and the third lens of the present invention may be glass lenses, and the second lens, the fourth lens, the fifth lens and the sixth lens may be plastic lenses.

In some embodiments, the optical lens satisfies the conditional expression: 11mm < TTL <14mm,5mm < f <8mm,7.5mm < IH <9.5mm, FNo <1.5, 60 DEG < FOV <75 DEG; wherein TTL represents the total optical length of the optical lens, f represents the effective focal length of the optical lens, IH represents the real image height corresponding to the maximum field angle of the optical lens, fno represents the aperture value of the optical lens, and FOV represents the maximum field angle of the optical lens. The optical lens provided by the embodiment of the invention has the characteristics of at least large image height, long focal length, large aperture and miniaturization.

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, G, H is the fourth-order, sixth-order, eighth-order, tenth-order, fourteen-order and sixteen-order curved 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 sequentially includes, from an object side to an imaging plane along an optical axis: the optical lens assembly includes 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, 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 convex, and an image-side surface S2 thereof is concave;

The second lens element L2 has positive refractive power, wherein an object-side surface S3 thereof is concave at a paraxial region thereof and an image-side surface S4 thereof is convex at the paraxial region thereof;

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, wherein an object-side surface S9 thereof is concave at a paraxial region thereof and an image-side surface S10 thereof is convex at the paraxial region thereof;

the sixth lens element L6 has positive refractive power, wherein an object-side surface S11 thereof is convex at a paraxial region thereof and an image-side surface S12 thereof is concave at the paraxial region thereof;

the object side surface S13 and the image side surface S14 of the optical filter G1 are planes;

the object side surface S15 and the image side surface S16 of the protective glass G2 are planes;

the imaging surface S17 is a plane.

The first lens L1 and the third lens L3 are glass spherical lenses, and the second lens L2, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are plastic 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 axial chromatic aberration curve, and the vertical chromatic aberration curve of the optical lens 100 are shown in fig. 2,3, 4, and 5, 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 angle of view (unit: °). As can be seen from the figure, the curvature of field of the meridional image plane and the sagittal image plane is controlled within ±0.4mm, which means that the optical lens 100 can satisfactorily correct curvature of field.

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 field angle (unit: °). As can be seen from the figure, the F-Tan θ distortion of the optical lens 100 is controlled within ±4%, the image compression in the edge angle region is gentle, and the definition of the unfolded image is effectively improved.

Fig. 4 shows an axial chromatic aberration diagram of example 1, which represents chromatic aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents axial chromatic aberration value (unit: mm), and the vertical axis represents normalized pupil radius. As can be seen from the figure, the offset of the axial chromatic aberration is controlled within ±0.07mm, which indicates that the optical lens 100 can better correct the axial chromatic aberration.

Fig. 5 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 (0.940 μm), with the horizontal axis representing a vertical axis color difference value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis representing a normalized field angle. As can be seen from the figure, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, indicating that the optical lens 100 can excellently correct chromatic aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Example 2

Referring to fig. 6, 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 axial chromatic aberration curve, and the vertical chromatic aberration curve of the optical lens 200 are shown in fig. 7, 8, 9, and 10, respectively. As can be seen from fig. 7, the meridional image plane and the field curvature of the sagittal image plane of the optical lens 200 are controlled within ±0.3mm, which means that the optical lens 200 can correct the field curvature well. As can be seen from fig. 8, the F-Tan θ distortion of the optical lens 200 is controlled within ±3.5%, and the image compression in the edge angle region is relatively gentle, thereby effectively improving the sharpness of the unfolded image. As can be seen from fig. 9, the offset of the axial chromatic aberration is controlled within ±0.08mm, which indicates that the optical lens 200 can better correct the axial chromatic aberration. As can be seen from fig. 10, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, which means that the optical lens 200 can excellently correct chromatic aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Example 3

Referring to fig. 11, 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 object side surface S1 of the first lens L1 is a concave surface; the image side surface S6 of the third lens L3 is concave; 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

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 axial chromatic aberration curve, and the vertical chromatic aberration curve of the optical lens 300 are shown in fig. 12, 13, 14, and 15, respectively. As can be seen from fig. 12, the meridional image plane and the field curvature of the sagittal image plane of the optical lens 300 are controlled within ±0.3mm, which means that the optical lens 300 can correct the field curvature well. As can be seen from fig. 13, the F-Tan θ distortion of the optical lens 300 is controlled within ±4%, and the image compression in the edge angle region is relatively gentle, effectively improving the sharpness of the unfolded image. As can be seen from fig. 14, the offset of the axial chromatic aberration is controlled within ±0.08mm, which indicates that the optical lens 300 can better correct the axial chromatic aberration. As can be seen from fig. 15, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.2μm, which means that the optical lens 300 can excellently correct chromatic aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Example 4

Referring to fig. 16, a schematic structural diagram of an optical lens 400 provided in embodiment 4 of the present invention is shown, and the main difference between the present embodiment and embodiment 1 is that: the object side surface S1 of the first lens L1 is a concave surface; the image side surface S2 of the first lens L1 is a convex surface; the image side surface S6 of the third lens L3 is concave; 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 400 in example 4 are shown in table 4-1.

TABLE 4-1

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

TABLE 4-2

In this embodiment, the field curvature curve, the F-Tan θ distortion curve, the axial chromatic aberration curve, and the vertical chromatic aberration curve of the optical lens 400 are shown in fig. 17, 18, 19, and 20, respectively. As can be seen from fig. 17, the meridional image plane and the field curvature of the sagittal image plane of the optical lens 400 are controlled within ±0.3mm, which means that the optical lens 400 can satisfactorily correct the field curvature. As can be seen from fig. 18, the F-Tan θ distortion of the optical lens 400 is controlled within ±2.5%, and the image compression in the edge angle region is relatively gentle, thereby effectively improving the sharpness of the unfolded image. As can be seen from fig. 19, the offset of the axial chromatic aberration is controlled within ±0.05mm, which indicates that the optical lens 400 can correct the axial chromatic aberration well. As can be seen from fig. 20, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, which means that the optical lens 400 can excellently correct chromatic aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Referring to table 5, 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 5

In summary, the optical lens provided by the present invention has at least the following advantages:

(1) The lens has the characteristic of long focus, and can better present larger local details, so that the picture is more concentrated and compact, thereby meeting the local shooting requirement; the large image surface characteristic of the lens can be realized, and the chip with larger size can be mounted, so that the high-definition imaging of the lens can be realized.

(2) The optical lens has a compact large aperture structure, the overall length of the optical lens is effectively shortened, and more luminous flux can enter the optical lens, so that the system can image clearly in a dim environment; meanwhile, the working wave band of the optical lens is in an infrared wave band, so that the infrared light source can be assisted to effectively improve the night imaging quality.

(3) Adopt glass to mould mixed structure, strengthened the transmissivity of light, optimized the offset of camera lens under different temperatures, can have good heat stability under the prerequisite that satisfies high pixel to can reduce cost.

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 six lenses, comprising, in order from an object side to an imaging plane along an optical axis:

a first lens having negative optical power;

2. The optical lens according to claim 1, wherein an effective focal length f of the optical lens and an aperture value Fno of the optical lens satisfy: 4mm < f/FNo <6mm.

3. 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: 1.5< TTL/f <2.5.

4. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f1 of the first lens satisfy: -20< f1/f < -3.

5. 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: 3< f2/f <7.

6. The optical lens of claim 1, wherein the object-side radius of curvature R3 of the second lens and the image-side radius of curvature R4 of the second lens satisfy: 1.1< R3/R4<2; the effective focal length f of the optical lens and the image side curvature radius R4 of the second lens satisfy the following conditions: -1< R4/f < -0.1.

7. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f4 of the fourth lens satisfy: 10< f4/f <30.

8. The optical lens of claim 1, wherein a focal length f1 of the first lens and a focal length f2 of the second lens satisfy: -5< f1/f2< -1.

9. The optical lens of claim 1, wherein a focal length f4 of the fourth lens and a focal length f5 of the fifth lens satisfy: 3< f4/f5<8.

10. The optical lens of claim 1, wherein the object-side effective aperture DM1 of the first lens and the object-side effective aperture DM3 of the third lens satisfy: 1< DM1/DM3<1.4; the object-side effective aperture DM3 of the third lens and the object-side effective aperture DM6 of the sixth lens satisfy: 0.6< DM3/DM6<1.

11. 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: 1.2< TTL/IH <1.8.