CN117930470A

CN117930470A - Optical lens

Info

Publication number: CN117930470A
Application number: CN202410333087.8A
Authority: CN
Inventors: 谢先国; 章彬炜
Original assignee: Jiangxi Lianyi Optics Co Ltd
Current assignee: Jiangxi Lianyi Optics Co Ltd
Priority date: 2024-03-22
Filing date: 2024-03-22
Publication date: 2024-04-26
Anticipated expiration: 2044-03-22
Also published as: CN117930470B

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 having positive optical power, the object side surface of which is a convex surface; a third lens having positive optical power, the image side surface of which is convex; a fourth lens having negative optical power, an image-side surface of which is concave at a paraxial region; a fifth lens having positive optical power, an image side surface of which is convex; a sixth lens element with negative refractive power having a convex object-side surface at a paraxial region and a concave image-side surface at a paraxial region; a seventh lens having negative optical power, an image-side surface of which is concave at a paraxial region; wherein, the effective focal length f, the maximum field angle FOV and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 40 ° < (f×fov)/IH <55 °. The optical lens provided by the invention has the advantages of at least miniaturization, large field angle, large target surface imaging and high pixel.

Description

Optical lens

Technical Field

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

Background

Along with continuous upgrading and updating of unmanned aerial vehicles, consumers have higher and higher requirements on functions of unmanned aerial vehicles, and ultra-high-pixel, large-aperture and wide-angle shooting becomes a main development trend of unmanned aerial vehicles. In order to pursue high-quality imaging, currently, all-glass lenses are mostly adopted by the mainstream unmanned aerial vehicle, the number of lenses is increased from 5-6 lenses to 7-8 lenses for correcting the optical path, but the weight and the volume of the glass lenses are difficult to reduce due to the restriction of the glass lenses, and the all-glass lenses meet the bottleneck period. Because plastic lens is lighter and thinner and has good plasticity, the lens adopting the plastic lens can be effectively lighter and thinner, and can realize shooting with a large field angle by combining the advantages of the plastic lens, and meanwhile, the light incoming quantity and imaging definition of the optical lens are ensured, so that the plastic lens is expected to be applied to high-end unmanned aerial vehicles and is a development trend of future unmanned aerial vehicle lenses. However, how to better realize the large field angle, large target surface imaging and high pixel performance of the lens is still an urgent problem to be solved.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an optical lens, which has at least the advantages of light weight, large field angle, large target surface imaging, and high pixel.

The invention provides an optical lens, seven lenses altogether, including in order from the object side to the imaging plane 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 having positive optical power, the object side surface of which is a convex surface;

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

a fourth lens having negative optical power, an image-side surface of which is concave at a paraxial region;

a fifth lens having positive optical power, an image side surface of which is convex;

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

A seventh lens having negative optical power, an image-side surface of which is concave at a paraxial region;

Wherein, the effective focal length f, the maximum field angle FOV and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 40 ° < (f×fov)/IH <55 °.

Further preferably, the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle satisfy: 0.75< TTL/IH <1.1.

Further preferably, the effective focal length f of the optical lens and the image height IH corresponding to the maximum field angle satisfy: 2.2< IH/f <3.5; the total optical length TTL and the effective focal length f of the optical lens meet the following conditions: 2.2< TTL/f <3.5.

Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2< f1/f < -1; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 1.8< R1/R2<8.

Further preferably, the effective focal length f of the optical lens and the object-side curvature radius R1 of the first lens satisfy: 0.5< R1/f <4.5; the effective focal length f of the optical lens and the image side curvature radius R2 of the first lens satisfy the following conditions: 0.2< R2/f <0.75.

Further preferably, the object-side light-transmitting half-aperture DM1 of the first lens and the image-side light-transmitting half-aperture DM14 of the seventh lens satisfy: 0.5< DM1/DM14<0.8.

Further preferably, the center thickness CT2 of the second lens and the center thickness CT3 of the third lens satisfy: 0.7< CT2/CT3<2; the center thickness CT3 of the third lens and the distance CT34 between the third lens and the fourth lens on the optical axis satisfy: 25< CT3/CT34<300.

Further preferably, a distance CT12 between the first lens and the second lens on the optical axis and a center thickness CT1 of the first lens satisfy: 2< CT12/CT1<3.5; the distance CT45 between the fourth lens and the fifth lens on the optical axis and the center thickness CT4 of the fourth lens satisfy: 2< CT45/CT4<4.

Further preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -20< f6/f < -0.2; the object-side curvature radius R11 of the sixth lens element and the image-side curvature radius R12 of the sixth lens element satisfy the following conditions: 1< R11/R12<8.

Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -3< f4/f < -2.

Compared with the prior art, the optical lens provided by the invention has the advantages that through specific surface shape arrangement and reasonable focal power distribution, particularly the sixth lens and the seventh lens adopt negative focal power, so that the optical lens is compact in structure, has a large field angle and high imaging quality, can be matched with a 1/1.3 inch large target surface chip to realize high-definition imaging, and can reasonably correct the integral aberration of the optical lens, so that the optical lens has high pixels, meanwhile, the overall length of the optical lens is effectively shortened, and the use requirements of the unmanned aerial vehicle for lightening, high image quality and wide-angle shooting are better met.

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 an axial chromatic aberration diagram of an optical lens in embodiment 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 a schematic structural diagram of an optical lens in embodiment 2 of the present invention.

Fig. 6 is a graph showing a field curvature of an optical lens in embodiment 2 of the present invention.

Fig. 7 is an axial chromatic aberration diagram of an optical lens in embodiment 2 of the present invention.

Fig. 8 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 2 of the present invention.

Fig. 9 is a schematic structural diagram of an optical lens in embodiment 3 of the present invention.

Fig. 10 is a graph showing a field curvature of an optical lens in embodiment 3 of the present invention.

Fig. 11 is a graph showing axial chromatic aberration of an optical lens in embodiment 3 of the present invention.

Fig. 12 is a graph showing a vertical axis chromatic aberration of an 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 optical lens sequentially comprises from an object side to an imaging surface along an optical axis: a first lens, a second lens, a diaphragm, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an optical filter.

In some embodiments, the first lens element may have a negative optical power, with a convex object-side surface and a concave image-side surface. The second lens may have positive optical power, and an object side surface thereof is convex. The third lens may have positive optical power, and an image side surface thereof is convex. The fourth lens may have negative optical power, with its image-side surface concave at a paraxial region. The fifth lens may have positive optical power, and an image side surface thereof is convex. The sixth lens element may have negative 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. The seventh lens may have negative optical power, with its image side surface concave at a paraxial region.

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 above conditional expression is satisfied, and the balance between the large field angle and the large target surface imaging of the optical lens is facilitated by reasonably limiting the relation among the focal length, the field angle and the image height of the optical lens.

In some embodiments, the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle satisfy: 0.75< TTL/IH <1.1. The method meets the above conditional expression, and can realize large target surface imaging and shorten the optical total length at the same time by reasonably limiting the ratio of the optical total length to the image height of the optical lens, realize the balance of miniaturization of the optical lens and large target surface imaging, and improve the market competitiveness.

In some embodiments, the effective focal length f of the optical lens and the image height IH corresponding to the maximum field angle satisfy: 2.2< IH/f <3.5; the total optical length TTL and the effective focal length f of the optical lens satisfy: 2.2< TTL/f <3.5. The method meets the above conditional expression, is favorable for realizing miniaturization of the lens, and is favorable for increasing the imaging area of the optical lens so as to offset the image compression caused by the distortion of the edge view field brought by a large view angle, thereby improving the imaging quality of the edge view field.

In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2< f1/f < -1; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 1.8< R1/R2<8. The focal length and the surface shape of the first lens are reasonably set, so that the change degree of the refraction angle of incident light is slowed down, excessive aberration caused by excessively strong refraction change is avoided, more light rays enter the rear optical system, and the overall imaging quality is improved while the field angle of the lens is increased.

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: 0.5< R1/f <4.5; the effective focal length f of the optical lens and the image side curvature radius R2 of the first lens satisfy: 0.2< R2/f <0.75. The above conditional expression is satisfied, and by reasonably setting the surface shape of the first lens, the light entering the first lens can have proper incident and emergent angles, which is beneficial to increasing the field angle of the lens, reducing the outer diameter of the lens and maintaining the miniaturization of the head of the system.

In some embodiments, the object-side light-transmitting half-aperture DM1 of the first lens and the image-side light-transmitting half-aperture DM14 of the seventh lens satisfy: 0.5< DM1/DM14<0.8. The balance between the wide angle and the large image surface of the lens can be better realized by meeting the above conditional expression, and the lens has smaller head outer diameter.

In some embodiments, the center thickness CT2 of the second lens and the center thickness CT3 of the third lens satisfy: 0.7< CT2/CT3<2; the center thickness CT3 of the third lens and the separation distance CT34 between the third lens and the fourth lens on the optical axis satisfy: 25< CT3/CT34<300. The thickness relation of the front lens and the rear lens of the diaphragm is reasonably set, so that various aberrations of the lens are balanced, the imaging quality of the optical lens is improved, the processing difficulty of the fourth lens is reduced, and the processability is improved.

In some embodiments, the separation distance CT12 between the first lens and the second lens on the optical axis and the center thickness CT1 of the first lens satisfy: 2< CT12/CT1<3.5; the distance CT45 between the fourth lens element and the fifth lens element on the optical axis and the center thickness CT4 of the fourth lens element satisfy: 2< CT45/CT4<4. The optical lens has the advantages that the condition is met, larger air space is reserved between the first lens and the second lens and between the fourth lens and the fifth lens, so that light entering the system is deflected slowly, correction difficulty of various aberrations is reduced, improvement of imaging quality of the optical lens is facilitated, and ultra-high pixel imaging of the lens is achieved.

In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -20< f6/f < -0.2; the object-side radius of curvature R11 of the sixth lens and the image-side radius of curvature R12 of the sixth lens satisfy: 1< R11/R12<8. The above conditional expression is satisfied, the focal length and the surface shape of the sixth lens are reasonably adjusted, so that the shape change of the sixth lens can be slowed down, the stray light is reduced, meanwhile, the aberration of the marginal view field can be effectively improved, and the overall imaging quality of the optical lens is improved

In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -3< f4/f < -2; the effective focal length f of the optical lens and the image-side curvature radius R8 of the fourth lens satisfy: 0.5< R8/f <2. The focal length and the surface shape of the fourth lens are reasonably controlled to reduce the correction difficulty of the aberration of the edge field of view, so that 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: 1< f2/f <3; the effective focal length f of the optical lens and the object-side curvature radius R3 of the second lens satisfy the following conditions: 0.5< R3/f <10. The above conditional expression is satisfied, and by reasonably setting the focal length and the surface shape of the second lens, incident light entering the system can be effectively converged, the correction difficulty of edge aberration and distortion is reduced, and the imaging quality of the optical lens is ensured.

In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.8< f3/f <1.6; the effective focal length f of the optical lens and the image-side curvature radius R6 of the third lens satisfy: -1< R6/f < -0.2. The lens meets the above conditional expression, is favorable for further converging light, reduces the difficulty of distortion correction of the edge view field, ensures that the lens has smaller distortion while realizing a large view angle, and improves the overall imaging quality.

In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.7< f5/f <2.5; the effective focal length f of the optical lens and the image-side curvature radius R10 of the fifth lens satisfy: -2< R10/f < -0.2. The convergence degree of incident light rays can be effectively slowed down by reasonably controlling the focal length and the surface shape of the fifth lens, and the large target surface imaging of the lens is facilitated.

In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: -5< f7/f < -0.5; the effective focal length f of the optical lens and the image-side curvature radius R14 of the seventh lens satisfy: 0.6< R14/f <8. The seventh lens can provide larger negative refractive power to facilitate increasing the incident angle of light entering an image plane, so that the lens can better match an imaging chip with a large CRA (chief ray incident angle) to realize high-definition imaging; meanwhile, the imaging area of the lens is increased, and the large target surface imaging of the lens is realized.

In some embodiments, the total optical length TTL and the maximum field angle FOV of the optical lens satisfy: 0.07mm/° < TTL/FOV <0.1mm/°. The lens can keep smaller total length while having larger field angle, thereby realizing the balance of miniaturization and wide angle of the lens.

In some embodiments, the maximum field angle FOV and aperture value Fno of the optical lens satisfy: 50 DEG < FOV/FNo <60 deg. The lens has a larger field angle and a larger aperture value when the conditional expression is satisfied.

In some embodiments, the effective focal length f and the optical back focal length BFL of the optical lens satisfy: 0.2< BFL/f <0.3. The lens has larger back focus, is beneficial to the assembly of the module, reduces interference and improves the production yield.

In some embodiments, the optical lens satisfies the conditional expression: 9.5mm < TTL <13mm,3mm < f <6mm,125 DEG < FOV <150 DEG, 11mm < IH <14mm,2.2< FNo <2.8, wherein TTL represents the total optical length of the optical lens, f represents the effective focal length of the optical lens, FOV represents the maximum field angle of the optical lens, IH represents the image height corresponding to the maximum field angle of the optical lens, and FNo represents the aperture value of the optical lens. The optical lens provided by the embodiment of the invention has the characteristics of at least larger field angle, larger target surface and miniaturization.

As an implementation mode, the seven lenses in the optical lens can all adopt plastic lenses or adopt a glass-plastic mixed material collocation structure, and preferably, the optical lens adopts the seven-lens glass-plastic mixed collocation structure, so that the optical lens can better match with a large target surface chip to realize high-definition imaging, and meanwhile, the reasonable balance of miniaturization, high pixels, light weight and wide viewing angle of the optical lens can also be realized. Specifically, the second lens may be a glass lens, and the first lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all plastic lenses; by adopting the glass-plastic mixed structure, the cost can be effectively reduced, the aberration can be corrected, the volume can be reduced, and an optical lens product with higher cost performance can be provided.

For better optical performance of the system, at least one aspheric lens is adopted in the lens, and each aspheric surface shape 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, 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 100 includes, in order from an object side to an imaging plane 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 a filter G1.

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 L2 has positive focal power, and an object side surface S3 and an image side surface S4 of the second lens L2 are both convex surfaces;

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

The fourth lens element L4 has negative refractive power, wherein an object-side surface S7 thereof is convex at a paraxial region thereof and an image-side surface S8 thereof is concave at the paraxial region thereof;

The fifth lens element L5 has positive refractive power, wherein an object-side surface S9 thereof is concave and an image-side surface S10 thereof is convex;

the sixth lens element L6 has negative 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 seventh lens element L7 with negative refractive power has a convex object-side surface S13 at a paraxial region and a concave image-side surface S14 at a paraxial region;

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

The imaging surface S17 is a plane.

The second lens L2 adopts a glass aspheric lens; the first lens L1, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are all 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, a field curvature curve, an axial chromatic aberration curve, and a vertical chromatic aberration curve of the optical lens 100 are shown in fig. 2,3, and 4, 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 ±0.05mm, which means that the optical lens 100 can correct curvature of field well.

Fig. 3 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 ±0.02mm, which indicates that the optical lens 100 can better correct the axial chromatic aberration.

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 (0.55 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 ±3 μm, which means that the optical lens 100 can better correct chromatic aberration of the fringe field of view and the secondary spectrum of the entire image plane.

Example 2

Referring to fig. 5, 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 object side surface S9 of the fifth lens L5 is convex; the object side surface S13 of the seventh lens L7 is a concave surface; 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 axial chromatic aberration curve, and the vertical chromatic aberration curve of the optical lens 200 are shown in fig. 6, 7, and 8, respectively. As can be seen from fig. 6, the curvature of field is controlled within ±0.1mm, which indicates that the curvature of field of the optical lens 200 is well corrected; as can be seen from fig. 7, the offset of the axial chromatic aberration is within ±0.03mm, which indicates that the axial chromatic aberration of the optical lens 200 is well corrected; as can be seen from fig. 8, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±3 μm, indicating that the vertical chromatic aberration of the optical lens 200 is well corrected; as can be seen from fig. 6, 7 and 8, the aberration of the optical lens 200 is well balanced, and has good optical imaging quality.

Example 3

Referring to fig. 9, a schematic diagram of an optical lens 300 according to embodiment 3 of the present invention is shown, and the main difference between the present embodiment and embodiment 1 is that: the image side surface S4 of the second lens L2 is a concave surface; the object side surface S5 of the third lens L3 is a convex surface; the object side surface S7 of the fourth lens L4 is a concave surface; the object side surface S13 of the seventh lens L7 is a concave surface; 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 axial chromatic aberration curve, and the vertical chromatic aberration curve of the optical lens 300 are shown in fig. 10, 11, and 12, respectively. As can be seen from fig. 10, the curvature of field is controlled within ±0.15mm, which indicates that the curvature of field of the optical lens 300 is well corrected; as can be seen from fig. 11, the offset of the axial chromatic aberration is within ±0.02mm, which indicates that the axial chromatic aberration of the optical lens 300 is well corrected; as can be seen from fig. 12, the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4 μm, indicating that the vertical chromatic aberration of the optical lens 300 is well corrected; as can be seen from fig. 10, 11 and 12, the aberrations of the optical lens 300 are well balanced, and have good optical imaging quality.

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 image height IH corresponding to the maximum field angle, the maximum field angle FOV, and the numerical values corresponding to each conditional expression in the embodiments.

TABLE 4 Table 4

Compared with the prior art, the optical lens provided by the invention has at least the following advantages:

(1) The balance of high pixel and light weight can be realized. Because the plastic lens is lighter and thinner, the optical lens provided by the invention adopts a glass-plastic mixed structure of one glass lens and six plastic lenses, and the balance of high pixel and light and thin optical lens is realized.

(2) The optical lens can realize large field angle and large target surface imaging, and can realize large angle shooting (125 degrees < FOV <150 degrees). Through reasonable balance of the total length and the image height of the optical lens, miniaturization (9.5 mm < TTL <13 mm) of the optical lens is realized, meanwhile, large target surface imaging (11 mm < IH <14 mm) of the optical lens is also realized, 1/1.3 inch large target surface chips can be matched to realize high-definition imaging, and the use requirements of high image quality and wide-angle shooting of an unmanned aerial vehicle are met.

In summary, the optical lens provided by the invention adopts a seven-piece glass-plastic mixed structure, and the structure of the optical lens is compact through specific surface shape arrangement and reasonable focal power distribution, so that the large field angle and large target surface imaging of the lens can be realized, and meanwhile, the optical lens has higher imaging quality, and can be matched with a 50M high-pixel chip to realize high-definition imaging; meanwhile, the integral aberration of the optical lens can be reasonably corrected, so that the optical lens has high pixels, the overall length of the optical lens is effectively shortened, and the use requirements of the unmanned aerial vehicle for light weight, high image quality and wide-angle shooting are better met.

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 of claim 1, wherein an image height IH corresponding to an optical total length TTL and a maximum field angle of the optical lens satisfies: 0.75< TTL/IH <1.1.

3. The optical lens according to claim 1, wherein an image height IH corresponding to an effective focal length f and a maximum field angle of the optical lens satisfies: 2.2< IH/f <3.5; the total optical length TTL and the effective focal length f of the optical lens meet the following conditions: 2.2< TTL/f <3.5.

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: -2< f1/f < -1; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 1.8< R1/R2<8.

5. The optical lens of claim 1, wherein an effective focal length f of the optical lens and an object-side radius of curvature R1 of the first lens satisfy: 0.5< R1/f <4.5; the effective focal length f of the optical lens and the image side curvature radius R2 of the first lens satisfy the following conditions: 0.2< R2/f <0.75.

6. The optical lens of claim 1, wherein the object-side light-transmitting half-aperture DM1 of the first lens and the image-side light-transmitting half-aperture DM14 of the seventh lens satisfy: 0.5< DM1/DM14<0.8.

7. The optical lens of claim 1, wherein a center thickness CT2 of the second lens and a center thickness CT3 of the third lens satisfy: 0.7< CT2/CT3<2; the center thickness CT3 of the third lens and the distance CT34 between the third lens and the fourth lens on the optical axis satisfy: 25< CT3/CT34<300.

8. The optical lens of claim 1, wherein a distance CT12 between the first lens and the second lens on the optical axis and a center thickness CT1 of the first lens satisfy: 2< CT12/CT1<3.5; the distance CT45 between the fourth lens and the fifth lens on the optical axis and the center thickness CT4 of the fourth lens satisfy: 2< CT45/CT4<4.

9. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f6 of the sixth lens satisfy: -20< f6/f < -0.2; the object-side curvature radius R11 of the sixth lens element and the image-side curvature radius R12 of the sixth lens element satisfy the following conditions: 1< R11/R12<8.

10. 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: -3< f4/f < -2.