CN116520537A - Optical lens - Google Patents

Optical lens Download PDF

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Publication number
CN116520537A
CN116520537A CN202310484314.2A CN202310484314A CN116520537A CN 116520537 A CN116520537 A CN 116520537A CN 202310484314 A CN202310484314 A CN 202310484314A CN 116520537 A CN116520537 A CN 116520537A
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CN
China
Prior art keywords
lens
optical lens
optical
image
focal length
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Pending
Application number
CN202310484314.2A
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Chinese (zh)
Inventor
廖宝发
魏文哲
王克民
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Jiangxi Lianchuang Electronic Co Ltd
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Jiangxi Lianchuang Electronic Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Jiangxi Lianchuang Electronic Co Ltd filed Critical Jiangxi Lianchuang Electronic Co Ltd
Priority to CN202310484314.2A priority Critical patent/CN116520537A/en
Publication of CN116520537A publication Critical patent/CN116520537A/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/001Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/0045Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having five or more lenses
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/001Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/006Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element at least one element being a compound optical element, e.g. cemented elements
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/001Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/008Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras designed for infrared light
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/14Optical objectives specially designed for the purposes specified below for use with infrared or ultraviolet radiation
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03BAPPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B30/00Camera modules comprising integrated lens units and imaging units, specially adapted for being embedded in other devices, e.g. mobile phones or vehicles

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Lenses (AREA)

Abstract

The invention provides an optical lens, which comprises seven lenses in sequence from an object side to an imaging surface along an optical axis: the first lens with negative focal power has a 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; a third lens having positive optical power; a diaphragm; a fourth lens element with positive refractive power having convex object-side and image-side surfaces; a fifth lens element with positive refractive power having convex object-side and image-side surfaces; the object side surfaces of the sixth lens with negative focal power are all concave surfaces; a seventh lens element with negative refractive power having a concave object-side surface and a convex image-side surface; the real image height IH and the entrance pupil diameter EPD corresponding to the maximum field angle of the optical lens satisfy the following conditions: 3.0< IH/EPD <4.0. The optical lens provided by the invention 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 invention relates to the technical field of imaging lenses, in particular to an optical lens.
Background
Along with the continuous improvement of the requirements of people on driving experience, the vehicle-mounted application optical lens is increasingly used in intelligent driving, and the position of the vehicle-mounted optical lens in the related industries of automobiles is continuously improved.
Advanced Driving Assistance Systems (ADASs) play an important role in intelligent driving, and collect environmental information through various lenses in combination with sensors to ensure driving safety of drivers. In addition to the requirements of the optical lens for the conventional ADAS system, the optical lens is required to have a light, thin, short and small shape, high pixels, high resolution and other characteristics, and the optical lens is required to be capable of clearly imaging under the condition of low illumination, so that the development of an optical lens with good imaging effect is required.
Disclosure of Invention
In view of the foregoing, an object of the present invention is to provide an optical lens having an advantage of excellent imaging quality.
The invention provides an optical lens, which comprises seven lenses in sequence from an object side to an imaging surface along an optical axis:
the first lens with negative focal power has a 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;
a third lens having positive optical power;
a diaphragm;
a fourth lens element with positive refractive power having convex object-side and image-side surfaces;
a fifth lens element with positive refractive power having convex object-side and image-side surfaces;
the object side surfaces of the sixth lens with negative focal power are all concave surfaces;
a seventh lens element with negative refractive power having a concave object-side surface and a convex image-side surface;
the real image height IH and the entrance pupil diameter EPD corresponding to the maximum field angle of the optical lens satisfy the following conditions: 3.0< IH/EPD <4.0.
Further preferably, the optical total length TTL and the effective focal length f of the optical lens satisfy: 6.0< TTL/f <9.0.
Further preferably, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 3.0< TTL/IH <5.0.
Further preferably, the maximum field angle FOV and the aperture value FNO of the optical lens satisfy: 55 DEG < FOV/FNO < 70 deg.
Further preferably, 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: d is 0.7 < 1 /IH/tan(FOV/2)<0.98。
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: -2.5<f 1 /f<-1.5。
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: 5.0<f 3 /f<8.0。
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<2.5。
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: -1.5<f 6 /f<-1.1。
Further preferably, the effective focal length f of the optical lens and the focal length f of the seventh lens 7 The method meets the following conditions: -11.0<f 7 /f<-9.0。
The optical lens provided by the invention 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.
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 MTF graph of the optical lens in example 1 of the present invention.
Fig. 4 is an axial aberration diagram of the 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 an MTF graph of the optical lens in example 2 of the present invention.
Fig. 9 is an axial aberration diagram of the 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 an MTF graph of an optical lens in example 3 of the present invention.
Fig. 14 is an axial 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 an MTF graph of the optical lens in example 4 of the present invention.
Fig. 19 is an axial aberration diagram of the 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.
Fig. 21 is a schematic structural diagram of an optical lens in embodiment 5 of the present invention.
Fig. 22 is a graph showing the field curvature of an optical lens in embodiment 5 of the present invention.
Fig. 23 is an MTF graph of an optical lens in example 5 of the present invention.
Fig. 24 is an axial aberration diagram of the optical lens in embodiment 5 of the present invention.
Fig. 25 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 5 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 present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of the present application and are not intended to limit the scope of the present 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 present application, use of "may" means "one or more embodiments of the present 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, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
The optical lens according to the embodiment of the invention 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, a seventh lens, an optical filter and protective glass.
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 element with negative refractive power has a concave object-side surface and a convex image-side surface; the third lens may have positive optical power; the fourth lens element may have positive refractive power, and both object-side and image-side surfaces thereof may be convex; the fifth lens element may have positive refractive power, and both object-side and image-side surfaces thereof may be convex; the sixth lens can have negative focal power, and the object side surfaces of the sixth lens are all concave surfaces; the seventh lens element with negative refractive power has a concave object-side surface and a convex image-side surface.
In some embodiments, the real image height IH and the entrance pupil diameter EPD corresponding to the maximum field angle of the optical lens satisfy: 3.0< IH/EPD <4.0. 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 optical total length TTL and the effective focal length f of the optical lens satisfy: 6.0< TTL/f <9.0. The requirements are met, enough space is ensured to adjust the lens structure, and the imaging effect is optimized.
In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 3.0< TTL/IH <5.0. The requirements of the large image surface and the lens size of the optical lens can be effectively balanced by meeting the range.
In some embodiments, the maximum field angle FOV and aperture value FNO of the optical lens satisfy: 55 DEG < FOV/FNO < 70 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 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: d is 0.7 < 1 IH/tan (FOV/2) < 0.98. The requirements are met, and the balance between the size of the optical lens and the large angle of view and the large image plane can be ensured.
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: -2.5<f 1 /f<-1.5. The requirements are met, the first lens can have proper negative focal power, and the inclination angle of incident light rays is reduced, so that the correction difficulty of various aberrations of the optical lens is reduced.
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: -15.0<f 2 /f<-8.0. Meets the above requirements and can make the second transparentThe lens has proper negative focal power, and can share the negative focal power of the front end of the optical lens, thereby being beneficial to avoiding overlarge light deflection caused by overlarge concentration of the first lens focal power and reducing the difficulty of chromatic aberration correction of the optical lens.
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: 5.0<f 3 /f<7.0. The requirements are met, the third lens has proper positive focal power, the light deflection angle is reduced while converging light, the light trend is stably transited, 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 fourth lens 4 The method meets the following conditions: 1.5<f 4 /f<2.5. The requirements are met, the fourth lens has proper positive focal power, the light deflection angle is reduced while converging light, the light trend is stably transited, 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: 1.2<f 5 /f<1.9. The requirements are met, the fifth lens has proper positive focal power, the light deflection angle is reduced while converging light, the light trend is stably transited, 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 is equal to the focal length f of the sixth lens 6 The method meets the following conditions: -1.5<f 6 /f<-1.1. The requirements are met, the sixth lens can have proper negative focal power, and the imaging area of the optical lens can be increased; meanwhile, the chromatic aberration of the optical lens can be optimized, 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 seventh lens 7 The method meets the following conditions: -11.0<f 7 /f<-9.0. Satisfying the above range, the seventh lens can be made to have an appropriate negative power,the imaging area of the optical lens can be increased.
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: 0.5< (IH/2)/(f×tan (FOV/2)) <0.6. The requirements are met, the optical distortion of the optical lens is well controlled, and the resolution of the optical lens is improved.
In some embodiments, the abbe number Vd of at least one of the fifth lens and the sixth lens satisfies: vd > 80, abbe number Vd of the fifth lens 5 And Abbe number Vd of the sixth lens 6 The method meets the following conditions: vd (Vd) 5 -Vd 6 > 60. Meeting the above range is beneficial to realizing confocal of visible light and infrared light.
In some embodiments, the fifth lens and the sixth 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.
In some embodiments, the second lens, the fourth lens and the seventh lens may each be a surface type of aspherical lens to improve the resolution quality.
For better optical performance of the system, a plurality of aspheric lenses are adopted in the lens, and the shape of each aspheric surface of the optical lens meets the following equation:
wherein z is the distance between the curved surface and the curved surface vertex in the optical axis direction, h is the distance between the optical axis and the curved surface, c is the curvature of the curved surface vertex, K is the quadric surface coefficient, and A, B, C, D, E, F is the second, fourth, sixth, eighth, tenth and twelfth order surface coefficients respectively.
The invention is further illustrated in the following examples. In various embodiments, the thickness, radius of curvature, and material selection portion of each lens in the optical lens may vary, and for specific differences, reference may be made to the parameter tables of the various embodiments. The following examples are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and any other changes, substitutions, combinations or simplifications that do not depart from the gist of the present invention are intended to be equivalent substitutes within the scope of the present invention.
Example 1
Referring to fig. 1, a schematic structural diagram of an optical lens provided in embodiment 1 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging plane along an optical axis: the first lens L1, the second lens L2, the third lens L3, the stop ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the filter G1, and the cover glass G2.
The first lens element L1 has negative refractive power, wherein an object-side surface S1 thereof is convex, and an image-side surface S2 thereof is concave;
the second lens element L2 has negative refractive power, wherein an object-side surface S3 thereof is concave, and an image-side surface S4 thereof is convex;
the third lens element L3 has positive refractive power, and both an object-side surface S5 and an image-side surface S6 thereof are convex;
a diaphragm ST;
the fourth lens element L4 has positive refractive power, and both an object-side surface S7 and an image-side surface S8 thereof are convex;
the fifth lens element L5 has positive refractive power, and both an object-side surface S9 and an image-side surface S10 thereof are convex;
the sixth lens element L6 has negative refractive power, and an object-side surface S10 and an image-side surface S11 thereof are concave;
the fifth lens element L5 and the sixth lens element L6 form a cemented lens assembly, i.e., the cemented surface between the image side surface of the fifth lens element L5 and the object side surface of the sixth lens element L6 is S10;
the seventh lens element L7 with negative focal power has a concave object-side surface S12 and a convex image-side surface S13;
the object side surface S14 and the image side surface S15 of the optical filter G1 are planes;
the object side surface S16 and the image side surface S17 of the protective glass G2 are planes;
the imaging surface S18 is a plane.
The 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, a field curve graph, an MTF graph, an axial aberration graph, and a vertical axis aberration graph of the optical lens 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 half angle of view (unit: °). From the graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within-0.02 mm to 0.03mm, which indicates that the optical lens can well correct the field curvature.
Fig. 3 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 0.4 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. 4 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 graph, the offset of the axial aberration is controlled within-10 mu m to 25 mu m, which indicates that the optical lens can better correct the axial aberration.
Fig. 5 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 6.5 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. 6, a schematic structural diagram of an optical lens provided in embodiment 2 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging plane along an optical axis: the first lens L1, the second lens L2, the third lens L3, the stop ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the filter G1, and the cover glass G2.
The first lens element L1 has negative refractive power, wherein an object-side surface S1 thereof is convex, and an image-side surface S2 thereof is concave;
the second lens element L2 has negative refractive power, wherein an object-side surface S3 thereof is concave, and an image-side surface S4 thereof is convex;
the third lens element L3 has positive refractive power, and both an object-side surface S5 and an image-side surface S6 thereof are convex;
a diaphragm ST;
the fourth lens element L4 has positive refractive power, and both an object-side surface S7 and an image-side surface S8 thereof are convex;
the fifth lens element L5 has positive refractive power, and both an object-side surface S9 and an image-side surface S10 thereof are convex;
the sixth lens element L6 has negative refractive power, and an object-side surface S10 and an image-side surface S11 thereof are concave;
the fifth lens element L5 and the sixth lens element L6 form a cemented lens assembly, i.e., the cemented surface between the image side surface of the fifth lens element L5 and the object side surface of the sixth lens element L6 is S10;
the seventh lens element L7 with negative focal power has a concave object-side surface S12 and a convex image-side surface S13;
the object side surface S14 and the image side surface S15 of the optical filter G1 are planes;
the object side surface S16 and the image side surface S17 of the protective glass G2 are planes;
the imaging surface S18 is a plane.
The 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, a field curve graph, an MTF graph, an axial aberration graph, and a vertical axis aberration graph of the optical lens are shown in fig. 7, 8, 9, and 10, respectively.
Fig. 7 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 graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within-0.01 mm to 0.02mm, which indicates that the optical lens can well correct the field curvature.
Fig. 8 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 0.4 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. 9 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-10 mu m to 20 mu m, which indicates that the optical lens can better correct the axial aberration.
Fig. 10 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 7 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. 11, a schematic structural diagram of an optical lens provided in embodiment 3 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging plane along an optical axis: the first lens L1, the second lens L2, the third lens L3, the stop ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the filter G1, and the cover glass G2.
The first lens element L1 has 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 positive refractive power, and both an object-side surface S7 and an image-side surface S8 thereof are convex;
the fifth lens element L5 has positive refractive power, and both an object-side surface S9 and an image-side surface S10 thereof are convex;
the sixth lens element L6 has negative refractive power, and an object-side surface S10 and an image-side surface S11 thereof are concave;
the fifth lens element L5 and the sixth lens element L6 form a cemented lens assembly, i.e., the cemented surface between the image side surface of the fifth lens element L5 and the object side surface of the sixth lens element L6 is S10;
the seventh lens element L7 with negative focal power has a concave object-side surface S12 and a convex image-side surface S13;
the object side surface S14 and the image side surface S15 of the optical filter G1 are planes;
the object side surface S16 and the image side surface S17 of the protective glass G2 are planes;
the imaging surface S18 is a plane.
The 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, a field curve graph, an MTF graph, an axial aberration graph, and a vertical axis aberration graph of the optical lens are shown in fig. 12, 13, 14, and 15, respectively.
Fig. 12 shows a field curve of example 3, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, the horizontal axis shows the amount of shift (unit: mm), and the vertical axis shows 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-0.01 mm-0.025 mm, which indicates that the optical lens can well correct the field curvature.
Fig. 13 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 0.4 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. 14 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-10 mu m to 15 mu m, which indicates that the optical lens can better correct the axial aberration.
Fig. 15 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 7 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. 16, a schematic structural diagram of an optical lens provided in embodiment 4 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging plane along an optical axis: the first lens L1, the second lens L2, the third lens L3, the stop ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the filter G1, and the cover glass G2.
The first lens element L1 has 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 convex, and an image-side surface S6 thereof is concave;
a diaphragm ST;
the fourth lens element L4 has positive refractive power, and both an object-side surface S7 and an image-side surface S8 thereof are convex;
the fifth lens element L5 has positive refractive power, and both an object-side surface S9 and an image-side surface S10 thereof are convex;
the sixth lens element L6 has negative refractive power, and an object-side surface S10 and an image-side surface S11 thereof are concave;
the fifth lens element L5 and the sixth lens element L6 form a cemented lens assembly, i.e., the cemented surface between the image side surface of the fifth lens element L5 and the object side surface of the sixth lens element L6 is S10;
the seventh lens element L7 with negative focal power has a concave object-side surface S12 and a convex image-side surface S13;
the object side surface S14 and the image side surface S15 of the optical filter G1 are planes;
the object side surface S16 and the image side surface S17 of the protective glass G2 are planes;
the imaging surface S18 is a plane.
The 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, a field curve graph, an MTF graph, an axial aberration graph, and a vertical axis aberration graph of the optical lens are shown in fig. 17, 18, 19, and 20, respectively.
Fig. 17 shows a field curve of example 4, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, the horizontal axis shows the amount of shift (unit: mm), and the vertical axis shows 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 +/-0.02 mm, which proves that the optical lens can well correct the field curvature.
Fig. 18 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 0.4 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 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 figure, the offset of the axial aberration is controlled within-5 mu m to 20 mu m, which indicates that the optical lens can better correct the axial aberration.
Fig. 20 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-4 mu m to 9 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 5
Referring to fig. 21, a schematic structural diagram of an optical lens provided in embodiment 5 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging plane along an optical axis: the first lens L1, the second lens L2, the third lens L3, the stop ST, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the filter G1, and the cover glass G2.
The first lens element L1 has 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 convex, and an image-side surface S6 thereof is concave;
a diaphragm ST;
the fourth lens element L4 has positive refractive power, and both an object-side surface S7 and an image-side surface S8 thereof are convex;
the fifth lens element L5 has positive refractive power, and both an object-side surface S9 and an image-side surface S10 thereof are convex;
the sixth lens element L6 with negative refractive power has a concave object-side surface S10 and a convex image-side surface S11;
the fifth lens element L5 and the sixth lens element L6 form a cemented lens assembly, i.e., the cemented surface between the image side surface of the fifth lens element L5 and the object side surface of the sixth lens element L6 is S10;
the seventh lens element L7 with negative focal power has a concave object-side surface S12 and a convex image-side surface S13;
the object side surface S14 and the image side surface S15 of the optical filter G1 are planes;
the object side surface S16 and the image side surface S17 of the protective glass G2 are planes;
the imaging surface S18 is a plane.
The relevant parameters of each lens in the optical lens in example 5 are shown in table 5-1.
TABLE 5-1
The surface profile parameters of the aspherical lens of the optical lens in example 5 are shown in table 5-2.
TABLE 5-2
In this embodiment, a field curve graph, an MTF graph, an axial aberration graph, and a vertical axis aberration graph of the optical lens are shown in fig. 22, 23, 24, and 25, respectively.
Fig. 22 shows a field curve of example 5, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, the horizontal axis shows the amount of shift (unit: mm), and the vertical axis shows 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-0.01 mm to 0.02mm, which indicates that the optical lens can well correct the field curvature.
Fig. 23 shows an MTF (modulation transfer function) graph of example 5, 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 0.5 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. 24 shows an axial aberration diagram of example 5, 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-10 mu m to 20 mu m, which indicates that the optical lens can better correct the axial aberration.
Fig. 25 shows a vertical axis color difference graph of example 5, 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-0.05 mu m to 5.5 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 6, 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 6
In summary, the optical lens provided by the invention has an infrared confocal function, meets the definition requirement of imaging at day and night, 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 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 (10)

1. An optical lens, seven lenses altogether, characterized in that, from the object side to the imaging plane along the optical axis, are:
the first lens with negative focal power has a 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;
a third lens having positive optical power;
a diaphragm;
a fourth lens element with positive refractive power having convex object-side and image-side surfaces;
a fifth lens element with positive refractive power having convex object-side and image-side surfaces;
a sixth lens with negative focal power, the object side surface of which is a concave surface;
a seventh lens element with negative refractive power having a concave object-side surface and a convex image-side surface;
the real image height IH and the entrance pupil diameter EPD corresponding to the maximum field angle of the optical lens satisfy the following conditions: 3.0< IH/EPD <4.0.
2. The optical lens of claim 1, wherein the optical total length TTL and the effective focal length f of the optical lens satisfy: 6.0< TTL/f <9.0.
3. The optical lens according to claim 1, wherein the real image height IH corresponding to the total optical length TTL and the maximum field angle of the optical lens satisfies: 3.0< TTL/IH <5.0.
4. The optical lens according to claim 1, wherein the maximum field angle FOV and aperture value FNO of the optical lens satisfy: 55 DEG < FOV/FNO < 70 deg.
5. The optical lens as claimed in claim 1, wherein the maximum field angle FOV and the true image height IH corresponding to the maximum field angle of the optical lens and the aperture D of the first lens object side face 1 The three parts are as follows: d is 0.7 < 1 /IH/tan(FOV/2)<0.98。
6. 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: -2.5<f 1 /f<-1.5。
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: 5.0<f 3 /f<8.0。
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<2.5。
9. 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: -1.5<f 6 /f<-1.1。
10. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f of the seventh lens 7 The method meets the following conditions: -11.0<f 7 /f<-9.0。
CN202310484314.2A 2023-05-04 2023-05-04 Optical lens Pending CN116520537A (en)

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