CN116577914B

CN116577914B - optical lens

Info

Publication number: CN116577914B
Application number: CN202310854035.0A
Authority: CN
Inventors: 凌兵兵; 鲍宇旻
Original assignee: Jiangxi Lianchuang Electronic Co Ltd
Current assignee: Jiangxi Lianchuang Electronic Co Ltd
Priority date: 2023-07-13
Filing date: 2023-07-13
Publication date: 2023-11-14
Anticipated expiration: 2043-07-13
Also published as: CN116577914A

Abstract

The application provides an optical lens, which comprises six lenses in sequence from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a convex object side surface and a concave image side surface; the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; a fourth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a fifth lens element with positive refractive power having convex object-side and image-side surfaces; a sixth lens element with negative refractive power having a convex object-side surface and a concave image-side surface; the object side surface curvature radius R of the second lens ₃ Radius of curvature R of image side ₄ The method meets the following conditions: -50<(R ₃ +R ₄ )/(R ₃ ‑R ₄ )<-30. The optical lens provided by the application improves the resolution of the optical lens, reduces the aberration and improves the imaging quality of the optical lens through reasonable configuration of the surface types of the lenses and reasonable collocation of the focal power.

Description

Optical lens

Technical Field

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

Background

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

The vehicle-mounted DMS system camera belongs to an imaging camera and is mainly applied to a cabin, and the main functions of the vehicle-mounted DMS system camera include functions of driver fatigue detection, face recognition and the like. In addition to the light and thin profile with a small front end diameter and the characteristics of high pixels, high resolution, etc., the conventional lens of the DMS system is required to have the optical lens capable of clearly imaging under the low-illumination condition, so that it is required to develop an optical lens with good imaging effect.

Disclosure of Invention

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

The application provides an optical lens, which comprises six lenses in sequence from an object side to an imaging surface along an optical axis:

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

the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface;

the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface;

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

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

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

the object side surface curvature radius R of the second lens ₃ Radius of curvature R of image side ₄ The method meets the following conditions: -50<(R ₃ +R ₄ )/(R ₃ -R ₄ )<-30。

Further preferably, the optical total length TTL and the effective focal length f of the optical lens satisfy: 5.0< TTL/f <6.0.

Further preferably, the effective focal length f of the optical lens and the maximum field angle FOV and the real image height IH corresponding to the maximum field angle satisfy: 0.4< (IH/2)/(f×tan (FOV/2)) <0.7.

Further preferably, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 2.0< IH/f <2.5.

Further preferably, the effective focal length f of the optical lens is equal to the focal length f of the first lens ₁ The method meets the following conditions: -1.7<f ₁ /f<-1.0。

Further preferably, the effective focal length f of the optical lens and the focal length f of the second lens ₂ The method meets the following conditions: f (f) ₂ /f<-130.0。

Further preferably, the effective focal length f of the optical lens and the focal length f of the third lens ₃ The method meets the following conditions: 1.5<f ₃ /f<2.1。

Further preferably, the effective focal length f of the optical lens and the focal length f of the fourth lens ₄ The method meets the following conditions: -1.5<f ₄ /f<-1.0。

Further preferably, the effective focal length f of the optical lens and the focal length f of the fifth lens ₅ The method meets the following conditions: 0.7<f ₅ /f<1.0。

Further preferably, the effective focal length f of the optical lens and the focal length f of the sixth lens ₆ The method meets the following conditions: -6.5<f ₆ /f<-5.5。

The optical lens provided by the application can effectively limit the length of the lens, is beneficial to realizing miniaturization of the optical lens, and improves the resolution of the optical lens, reduces aberration and improves the imaging quality of the optical lens through reasonable configuration of the lens surfaces and reasonable collocation of optical power.

Drawings

The foregoing and/or additional aspects and advantages of the application 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 application.

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

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

Fig. 4 is an MTF graph of the optical lens in example 1 of the present application.

Fig. 5 is a graph showing the relative illuminance of the optical lens in embodiment 1 of the present application.

Fig. 6 is an axial aberration diagram of the optical lens in embodiment 1 of the present application.

Fig. 7 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 1 of the present application.

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

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

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

Fig. 11 is an MTF graph of the optical lens in example 2 of the present application.

Fig. 12 is a graph showing the relative illuminance of the optical lens in embodiment 2 of the present application.

Fig. 13 is an axial aberration diagram of an optical lens in embodiment 2 of the present application.

Fig. 14 is a vertical axis chromatic aberration chart of the optical lens in embodiment 2 of the present application.

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

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

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

Fig. 18 is an MTF graph of the optical lens in example 3 of the present application.

Fig. 19 is a graph showing the relative illuminance of the optical lens in embodiment 3 of the present application.

Fig. 20 is an axial aberration diagram of an optical lens in embodiment 3 of the present application.

Fig. 21 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 3 of the present application.

Fig. 22 is a schematic structural diagram of an optical lens in embodiment 4 of the present application.

Fig. 23 is a graph showing a field curvature of an optical lens in embodiment 4 of the present application.

FIG. 24 is a graph showing F-Tanθ distortion of an optical lens in example 4 of the present application.

Fig. 25 is an MTF graph of the optical lens in example 4 of the present application.

Fig. 26 is a graph showing the relative illuminance of the optical lens in embodiment 4 of the present application.

Fig. 27 is an axial aberration diagram of an optical lens in embodiment 4 of the present application.

Fig. 28 is a vertical axis chromatic aberration chart of the optical lens in embodiment 4 of the application.

The application 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 application.

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 according to the embodiment of the application includes, in order from an object side to an image side along an optical axis: the optical lens comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and an optical filter.

In some embodiments, the first lens may have negative optical power, which facilitates reducing the tilt angle of incident light rays, thereby achieving effective sharing of the large field of view of the object. The object side surface of the first lens is a convex surface, and the image side surface is a concave surface, so that the light rays with the edge view fields can be collected as much as possible and enter the rear optical lens, and the collection of the light rays with a large angle can be realized.

In some embodiments, the second lens element may have negative focal power, the object-side surface of the second lens element is concave, and the image-side surface of the second lens element is convex, so that the negative focal power of the front end of the lens element can be shared, thereby reducing excessive deflection of light rays caused by excessive concentration of the focal power of the first lens element, and reducing difficulty in chromatic aberration correction of the optical lens element.

In some embodiments, the third lens may have positive optical power, which is beneficial to converging light while reducing the light deflection angle, so that the light trend is smoothly transited. The object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface, so that the influence of spherical aberration and astigmatism generated by the third lens on the optical lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the fourth lens element may have negative refractive power, and the object-side surface thereof is convex, and the image-side surface thereof is concave, so as to balance various aberrations generated by the optical lens element and improve the imaging quality of the optical lens element.

In some embodiments, the fifth lens may have positive optical power, which is advantageous for improving the light converging power of the optical lens. The object side surface and the image side surface of the fifth lens are convex, so that spherical aberration and coma aberration generated by the fifth lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the sixth lens may have negative optical power, which is beneficial to increasing the imaging area of the optical lens and improving the imaging quality of the optical lens. The object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a concave surface, so that the chromatic aberration of the optical lens can be optimized, and the imaging quality of the optical lens can be improved.

In some embodiments, the second lens has an object-side radius of curvature R ₃ Radius of curvature R of image side ₄ The method meets the following conditions: -50<(R ₃ +R ₄ )/(R ₃ -R ₄ )<-30. The curvature radius of the object side surface and the curvature radius of the image side surface of the second lens are adjusted to meet the range, so that the correction of higher-order aberration is enhanced.

In some embodiments, the optical total length TTL and the effective focal length f of the optical lens satisfy: 5.0< TTL/f <6.0. The length of the 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 focal length f of the optical lens and the maximum field angle FOV and the real image height IH corresponding to the maximum field angle satisfy: 0.4< (IH/2)/(f×tan (FOV/2)) <0.7. The optical lens meets the range, is beneficial to balance between the size of the angle of view and the F-Tan theta distortion size, and improves the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 2.0< IH/f <2.5. The optical lens meets the range, is beneficial to balance between the size of the angle of view and the F-Tan theta distortion size, and improves the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens is equal to the focal length f of the first lens ₁ The method meets the following conditions: -1.7<f ₁ /f<-1.0. The range is satisfied, the first lens has proper negative focal power, smooth transition of light trend is facilitated, and meanwhile, large-angle light enters the rear lens as much as possible, so that the illuminance of the lens is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the second lens ₂ The method meets the following conditions: f (f) ₂ /f<-130.0. The range is satisfied, the second lens adopts a larger focal length, and the angle of deflection of the incident light can be reduced while the deflection of the incident light of the front end lens is shared.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the third lens ₃ The method meets the following conditions: 1.5<f ₃ /f<2.1. The range is satisfied, so that the third lens has proper positive focal power, the influence of spherical aberration and astigmatism generated by the third lens on the optical lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the fourth lens ₄ The method meets the following conditions: -1.5<f ₄ /f<-1.0. The range is satisfied, so that the fourth lens has proper negative focal power, various aberrations generated by the optical lens are balanced, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f of the fifth lens ₅ The method meets the following conditions: 0.7<f ₅ /f<1.0. The range is satisfied, so that the fifth lens has proper positive focal power, the spherical aberration and the coma aberration generated by the fifth lens can be reduced, and the imaging quality of the optical lens is improved.

In some embodiments, the effective focal length f of the optical lens is equal to the focal length f of the sixth lens ₆ The method meets the following conditions: -6.5<f ₆ /f<-5.5. The range is satisfied, so that the sixth lens has proper negative focal power, the imaging area of the optical lens is increased, the chromatic aberration of the optical lens can be optimized, and the imaging quality of the optical lens is improved.

In some embodiments, the maximum field angle FOV of the optical lens satisfies: 115 ° < FOV <145 °. Satisfying the above range, the optical lens can be realized to have a large angle of view.

In some embodiments, the maximum field angle FOV and aperture value FNO of the optical lens satisfy: 55 DEG < FOV/FNO < 75 deg. The method meets the range, is favorable for expanding the field angle of the optical lens and increasing the aperture of the optical lens, is favorable for acquiring more scene information by the optical lens, meets the requirement of large-range detection, and is favorable for improving the problem that the relative brightness of the edge field of view is fast to drop by realizing the characteristic of the large aperture, 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: 2.0< TTL/IH <2.5. The requirements of high image height and miniaturization of the optical lens can be effectively balanced by meeting the range.

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: 4.0< IH/EPD <5.0. The range is satisfied, the width of the light beam entering the optical lens can be increased, so that the brightness of the optical lens at the image plane is improved, and the occurrence of dark angles is avoided.

In some embodiments, the maximum field angle FOV and the real image height IH corresponding to the maximum field angle of the optical lens and the aperture D of the first lens object side surface ₁ The three parts are as follows: 0.3 < D ₁ IH/tan (FOV/2) < 0.6. The balance between the size of the optical lens, the angle of view and the image plane can be ensured by meeting the above range.

In some embodiments, the fourth lens and the fifth lens can be glued to form a glued lens, so that chromatic aberration of the optical lens can be effectively corrected, decentered sensitivity of the optical lens can be reduced, aberration of the optical lens can be balanced, and imaging quality of the optical lens can be improved; the assembly sensitivity of the optical lens can be reduced, the processing technology difficulty of the optical lens is further reduced, and the assembly yield 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 application 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 application, but the embodiments of the present application 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 application are intended to be equivalent substitutes within the scope of the present application.

Example 1

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

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

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

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

a diaphragm ST;

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

the fifth lens element L5 has positive refractive power, and both an object-side surface S8 and an image-side surface S9 thereof are convex;

the fourth lens element L4 and the fifth lens element L5 form a cemented lens assembly, i.e., a cemented surface between the image side surface of the fourth lens element L4 and the object side surface of the fifth lens element L5 is S8;

the sixth lens element L6 with negative refractive power has a convex object-side surface S10 and a concave image-side surface S11;

the object side surface S12 and the image side surface S13 of the optical filter G1 are planes;

the imaging surface S14 is a plane.

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

TABLE 1-1

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

TABLE 1-2

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

Fig. 2 shows a field curve of example 1, which indicates the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, the horizontal axis indicates the amount of shift (unit: mm), and the vertical axis indicates the half angle of view (unit: °). From the figure, the field curvature of the meridian image plane and the sagittal image plane is controlled within-0.12 mm to 0mm, which indicates that the optical lens can well correct the field curvature.

Fig. 3 shows the F-Tan θ distortion curve of example 1, which represents the F-Tan θ distortion of light rays of different wavelengths at different image heights on the imaging plane, the horizontal axis represents the F-Tan θ distortion (unit:%) and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within-40% -0, the image compression of the edge angle area is gentle, and the definition of the unfolded image is effectively improved.

Fig. 4 shows an MTF (modulation transfer function) graph of example 1, which represents the lens imaging modulation degree of different spatial frequencies at each view field, the horizontal axis represents the spatial frequency (unit: lp/mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF values of the embodiment are above 0.3 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process of the field of view from the center to the edge, and the MTF image has better imaging quality and better detail resolution under the conditions of low frequency and high frequency.

Fig. 5 shows the relative illuminance curve of example 1, which represents the relative illuminance values for different field angles on the imaging plane, the horizontal axis represents the half field angle (in: °), and the vertical axis represents the relative illuminance (in:%). As can be seen from the figure, the relative illuminance value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens has better relative illuminance.

Fig. 6 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 offset of the axial aberration is controlled within-45 mu m to 35 mu m, which indicates that the optical lens can better correct the axial aberration.

Fig. 7 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 graph, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-2 mu m to 8 mu m, which shows that the optical lens can excellently correct chromatic aberration of an edge view field and a secondary spectrum of the whole image surface.

Example 2

Referring to fig. 8, a schematic structural diagram of an optical lens provided in embodiment 2 of the present application is shown, and the present embodiment is mainly characterized in that the optical parameters such as the radius of curvature and the thickness of the lens are different from those of embodiment 1.

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

TABLE 2-1

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

TABLE 2-2

In this embodiment, the field curvature curve, the F-Tan θ distortion curve, the MTF curve, the relative illuminance curve, the axial aberration curve, and the vertical chromatic aberration curve of the optical lens are shown in fig. 9, 10, 11, 12, 13, and 14, respectively.

Fig. 9 shows a field curvature curve of example 2, which indicates the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, the horizontal axis indicates the amount of shift (unit: mm), and the vertical axis indicates the half angle of view (unit: °). From the figure, the field curvature of the meridian image plane and the sagittal image plane is controlled within-0.12 mm to 0mm, which indicates that the optical lens can well correct the field curvature.

Fig. 10 shows an F-Tan θ distortion curve of example 2, which represents F-Tan θ distortion of light rays of different wavelengths at different image heights on an imaging plane, the horizontal axis represents F-Tan θ distortion (unit:%) and the vertical axis represents half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within-40% -0, the image compression of the edge angle area is gentle, and the definition of the unfolded image is effectively improved.

Fig. 11 shows an MTF (modulation transfer function) graph of example 2, which represents the lens imaging modulation degree of different spatial frequencies at each view field, the horizontal axis represents the spatial frequency (unit: lp/mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF values of the embodiment are above 0.3 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process of the field of view from the center to the edge, and the MTF image has better imaging quality and better detail resolution under the conditions of low frequency and high frequency.

Fig. 12 shows the relative illuminance curve of example 2, which represents the relative illuminance values for different field angles on the imaging plane, the horizontal axis represents the half field angle (in: °), and the vertical axis represents the relative illuminance (in:%). As can be seen from the figure, the relative illuminance value of the optical lens is still greater than 70% at the maximum half field angle, which indicates that the optical lens has better relative illuminance.

Fig. 13 shows an axial aberration diagram of example 2, 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 offset of the axial aberration is controlled within-45 mu m to 35 mu m, which indicates that the optical lens can better correct the axial aberration.

Fig. 14 shows a vertical axis color difference graph of example 2, 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 graph, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-2 mu m to 8 mu m, which shows that the optical lens can excellently correct chromatic aberration of an edge view field and a secondary spectrum of the whole image surface.

Example 3

Referring to fig. 15, a schematic structural diagram of an optical lens provided in embodiment 3 of the present application is shown, and the present embodiment is mainly characterized in that the optical parameters such as the radius of curvature and the thickness of the lens are different from those of embodiment 1.

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

TABLE 3-1

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

TABLE 3-2

In this embodiment, the field curve graph, the F-Tan θ distortion graph, the MTF graph, the relative illuminance graph, the axial aberration graph, and the vertical axis aberration graph of the optical lens are shown in fig. 16, 17, 18, 19, 20, and 21, respectively.

Fig. 16 shows a field curvature curve of example 3, which indicates the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, the horizontal axis indicates the amount of shift (unit: mm), and the vertical axis indicates the half angle of view (unit: °). From the graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within-0.15 mm to 0.02mm, which indicates that the optical lens can well correct the field curvature.

Fig. 17 shows an F-Tan θ distortion curve of example 3, which represents F-Tan θ distortion of light rays of different wavelengths at different image heights on an imaging plane, the horizontal axis represents F-Tan θ distortion (unit:%) and the vertical axis represents half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within-60% -0, the image compression of the edge angle area is gentle, and the definition of the unfolded image is effectively improved.

Fig. 18 shows an MTF (modulation transfer function) graph of example 3, which represents the lens imaging modulation degree of different spatial frequencies at each view field, the horizontal axis represents the spatial frequency (unit: lp/mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF values of the embodiment are above 0.3 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process of the field of view from the center to the edge, and the MTF image has better imaging quality and better detail resolution under the conditions of low frequency and high frequency.

Fig. 19 shows the relative illuminance curve of example 3, which represents the relative illuminance values for different field angles on the imaging plane, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illuminance (unit:%). As can be seen from the figure, 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 better relative illuminance.

Fig. 20 shows an axial aberration diagram of example 3, 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 graph, the offset of the axial aberration is controlled within-50 mu m to 30 mu m, which indicates that the optical lens can better correct the axial aberration.

Fig. 21 shows a vertical axis color difference graph of example 3, 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 graph, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-2 mu m to 8 mu m, which shows that the optical lens can excellently correct chromatic aberration of an edge view field and a secondary spectrum of the whole image surface.

Example 4

Referring to fig. 22, a schematic structural diagram of an optical lens provided in embodiment 4 of the present application is shown, and the present application is mainly characterized in that the optical parameters such as the radius of curvature and the thickness of the lens are different from those of embodiment 1.

The relevant parameters of each lens in the optical lens 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 curve, the F-Tan θ distortion curve, the MTF curve, the relative illuminance curve, the axial aberration curve, and the vertical chromatic aberration curve of the optical lens are shown in fig. 23, 24, 25, 26, 27, and 28, respectively.

Fig. 23 shows a field curvature curve of example 4, in which the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane is shown, the horizontal axis represents the amount of shift (unit: mm), and the vertical axis represents the half angle of view (unit: °). From the graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within-0.15 mm to 0.05mm, which indicates that the optical lens can well correct the field curvature.

Fig. 24 shows an F-Tan θ distortion curve of example 4, which represents F-Tan θ distortion of light rays of different wavelengths at different image heights on an imaging plane, the horizontal axis represents F-Tan θ distortion (unit:%) and the vertical axis represents half field angle (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within-60% -0, the image compression of the edge angle area is gentle, and the definition of the unfolded image is effectively improved.

Fig. 25 shows an MTF (modulation transfer function) graph of example 4, which represents the lens imaging modulation degree of different spatial frequencies at each view field, the horizontal axis represents the spatial frequency (unit: lp/mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF values of the embodiment are above 0.3 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve is uniformly and smoothly reduced in the process of the field of view from the center to the edge, and the MTF image has better imaging quality and better detail resolution under the conditions of low frequency and high frequency.

Fig. 26 shows the relative illuminance curve of example 4, which represents the relative illuminance values for different field angles on the imaging plane, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illuminance (unit:%). As can be seen from the figure, 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 better relative illuminance.

Fig. 27 shows an axial aberration diagram of example 4, 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 graph, the offset of the axial aberration is controlled within-45 mu m to 40 mu m, which indicates that the optical lens can better correct the axial aberration.

Fig. 28 shows a vertical axis color difference graph of example 4, 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 graph, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within-2 mu m to 10 mu m, which shows that the optical lens can excellently correct chromatic aberration of an edge view field and a secondary spectrum of the whole image surface.

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, the maximum field angle FOV and the numerical value corresponding to each conditional expression in the embodiments.

TABLE 5

In summary, the optical lens provided by the application can effectively limit the length of the lens, is beneficial to realizing miniaturization of the optical lens, and improves the resolution of the optical lens, reduces aberration and improves the imaging quality of the optical lens through reasonable configuration of the lens surfaces and reasonable collocation of optical power.

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 application. 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 application and are described in detail herein without thereby limiting the scope of the application. 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 application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims

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

the object side surface curvature radius R of the second lens ₃ Radius of curvature R of image side ₄ The method meets the following conditions: -50<(R ₃ +R ₄ )/(R ₃ -R ₄ )<-30；

The real image height IH corresponding to the effective focal length f and the maximum field angle of the optical lens meets the following conditions: 2.19< IH/f <2.5.

2. The optical lens of claim 1, wherein the optical total length TTL and the effective focal length f of the optical lens satisfy: 5.0< TTL/f <6.0.

3. The optical lens according to claim 1, wherein the effective focal length f of the optical lens satisfies a real image height IH corresponding to a maximum field angle FOV and a maximum field angle: 0.4< (IH/2)/(f×tan (FOV/2)) <0.7.

4. The optical lens according to claim 1, wherein the real image height IH and the entrance pupil diameter EPD corresponding to the maximum field angle of the optical lens satisfy: 4.0< IH/EPD <5.0.

5. The optical lens of claim 1, wherein an effective focal length f of the optical lens is equal to a focal length f of the first lens ₁ The method meets the following conditions: -1.7<f ₁ /f<-1.0。

6. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f of the second lens ₂ The method meets the following conditions: f (f) ₂ /f<-130.0。

7. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f of the third lens ₃ The method meets the following conditions: 1.5<f ₃ /f<2.1。

8. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f of the fourth lens ₄ The method meets the following conditions: -1.5<f ₄ /f<-1.0。

9. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f of the fifth lens ₅ The method meets the following conditions: 0.7<f ₅ /f<1.0。

10. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f of the sixth lens ₆ The method meets the following conditions: -6.5<f ₆ /f<-5.5。