CN115951482B - Optical lens - Google Patents
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- CN115951482B CN115951482B CN202310245587.1A CN202310245587A CN115951482B CN 115951482 B CN115951482 B CN 115951482B CN 202310245587 A CN202310245587 A CN 202310245587A CN 115951482 B CN115951482 B CN 115951482B
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Abstract
The invention provides an optical lens, seven in totalThe lens sheet is characterized in that the lens sheet sequentially comprises 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; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a third lens having negative optical power; the object side surface and the image side surface of the lens are both concave surfaces and have positive focal power, and the object side surface and the image side surface of the lens are both convex surfaces; a diaphragm; 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 concave object-side and image-side surfaces; a seventh lens element with positive optical power having convex object-side and image-side surfaces; 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＜‑150。
Description
Technical Field
The present invention relates to the field of optical lenses, and in particular, to an optical lens.
Background
With the development of the intellectualization of automobiles, the driving assistance function of the automobiles is gradually enhanced, wherein the visual information acquisition is a core tool. Along with the improvement of the automatic driving level, the requirements on the vehicle-mounted camera are gradually increased, and especially the front-mounted camera is improved. The front camera can enhance active safety and driver auxiliary functions, such as Automatic Emergency Braking (AEB), adaptive Cruise Control (ACC), lane Keeping Auxiliary System (LKAS), traffic Jam Auxiliary (TJA) and the like, and has the defects of large number of lenses, overlong total optical length and the like while meeting the advantages of high resolution, large field angle, good environmental adaptability and the like, and is unfavorable for miniaturization of an electronic system.
Disclosure of Invention
In view of the foregoing, it is an object of the present invention to provide an optical lens capable of solving one or more of the above-mentioned problems.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
an optical lens comprises seven lenses in sequence from an object side to an imaging surface along an optical axis:
the first lens with negative focal power has a convex object side surface and a concave image side surface; a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface; a third lens having negative optical power; the object side surface and the image side surface are concave surfaces; a fourth lens element with positive refractive power having convex object-side and image-side surfaces; a diaphragm; a fifth lens with positive focal power, the object side surface and the image side surface of the fifth lens are convexA noodle; a sixth lens element with negative refractive power having concave object-side and image-side surfaces; a seventh lens element with positive optical power having convex object-side and image-side surfaces; 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＜-150。
Further, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 8.0 and less than 13.0.
Further, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: IH/f is more than 1.5 and less than 2.0.
Further, the maximum field angle FOV and the aperture value FNO of the optical lens satisfy: FOV/FNO is less than 90 DEG and less than 110 deg.
Further, 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: 85 DEG < f X FOV/IH < 120 deg.
Further, an effective focal length f of the optical lens and a focal length f of the first lens 1 The method meets the following conditions: -4.0 < f 1 /f＜0。
Further, an effective focal length f of the optical lens and a combined focal length f of the first lens to the fourth lens 14 The method meets the following conditions: f is more than 4.0 and less than 14 /f＜6.0。
Further, an effective focal length f of the optical lens and a combined focal length f of the fifth lens to the seventh lens 57 The method meets the following conditions: f is more than 2.0 and less than 57 /f＜4.0。
Further, the object-side surface radius of curvature R of the second lens 3 Radius of curvature R of image side 4 The method meets the following conditions: r is more than 1.0 and less than 3 /R 4 ＜1.4。
Further, the sum Σct of the total optical length TTL of the optical lens and the center thicknesses of the first lens to the seventh lens along the optical axis respectively satisfies: sigma CT/TTL is less than 0.6 and less than 0.8.
Compared with the prior art, the invention has the beneficial effects that: the lens shape and the focal power combination among the lenses are reasonably matched, so that the effects of large view field, large aperture and miniaturization are realized.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
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 according to embodiment 1 of the present invention.
Fig. 2 is a graph showing a field curvature of an optical lens in embodiment 1 of the present invention.
Fig. 3 is a graph showing the relative illuminance of the optical lens in embodiment 1 of the present invention.
Fig. 4 is an MTF graph of the optical lens in example 1 of the present invention.
Fig. 5 is an axial aberration diagram of the optical lens in embodiment 1 of the present invention.
Fig. 6 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 1 of the present invention.
Fig. 7 is a schematic structural diagram of an optical lens according to embodiment 2 of the present invention.
Fig. 8 is a graph showing the field curvature of the optical lens in embodiment 2 of the present invention.
Fig. 9 is a graph showing the relative illuminance of the optical lens in embodiment 2 of the present invention.
Fig. 10 is an MTF graph of the optical lens in example 2 of the present invention.
Fig. 11 is an axial aberration diagram of an optical lens in embodiment 2 of the present invention.
Fig. 12 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 2 of the present invention.
Fig. 13 is a schematic structural diagram of an optical lens in embodiment 3 of the present invention.
Fig. 14 is a graph showing the field curvature of the optical lens in embodiment 3 of the present invention.
Fig. 15 is a graph showing the relative illuminance of the optical lens in embodiment 3 of the present invention.
Fig. 16 is an MTF graph of an optical lens in example 3 of the present invention.
Fig. 17 is an axial aberration diagram of an optical lens in embodiment 3 of the present invention.
Fig. 18 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 3 of the present invention.
Fig. 19 is a schematic structural diagram of an optical lens in embodiment 4 of the present invention.
Fig. 20 is a graph showing the field curvature of an optical lens in embodiment 4 of the present invention.
Fig. 21 is a graph showing the relative illuminance of the optical lens in embodiment 4 of the present invention.
Fig. 22 is an MTF graph of the optical lens in example 4 of the present invention.
Fig. 23 is an axial aberration diagram of the optical lens in embodiment 4 of the present invention.
Fig. 24 is a graph showing a vertical axis chromatic aberration of an optical lens in embodiment 4 of the present invention.
Detailed Description
For a better understanding of the invention, various aspects of the invention will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed description are merely illustrative of embodiments of the invention and are not intended to limit the scope of the invention in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.
It should be noted that in the present specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. Accordingly, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present invention.
In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. In particular, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are not drawn to scale.
Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, then the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side of the lens, and the surface of each lens closest to the imaging plane is referred to as the image side of the lens.
It will be further understood that the terms "comprises," "comprising," "includes," "including," "having," "containing," and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when an expression such as "at least one of … …" occurs after a list of features listed, the entire listed feature is modified instead of modifying a separate element in the list. Furthermore, when describing embodiments of the invention, use of "may" means "one or more embodiments of the invention. Also, the term "exemplary" is intended to refer to an example or illustration.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.
The optical lens according to the embodiment of the invention includes, in order from an object side to an image side: the optical lens comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens, an optical filter and protective glass.
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. Further, the refractive index Nd of the first lens is larger than 1.70, and the first lens with a higher refractive index is beneficial to reducing the effective working caliber of the first lens, so that the problem that the caliber of the rear end lens of the optical lens is too large due to excessive divergence of light is avoided.
In some embodiments, the second lens may have negative focal power, so that the negative focal power of the front end of the optical lens can be shared, thereby being beneficial to avoiding overlarge light deflection caused by overlarge focal power of the first lens, and reducing the difficulty of chromatic aberration correction of the optical lens. The object side surface of the second lens is a convex surface, and the image side surface is a concave surface, so that light rays emitted after passing through the first lens are collected, the light rays are enabled to stably transition in trend, and the imaging quality of the optical lens is improved.
In some embodiments, the third 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 and the image side surface of the third lens are concave surfaces, so that edge view field light rays can be folded, various high-order aberration caused by excessive divergence of the light rays is avoided, and the imaging quality of the optical lens is improved.
In some embodiments, the fourth 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 and the image side surface of the fourth lens are convex, so that the influence of coma aberration generated by the fourth lens on the optical lens is reduced, and the imaging quality of the optical lens is improved.
In some embodiments, the fifth lens may have positive optical power, so as to reduce the light deflection angle while converging light, make the light trend transition smoothly, balance various aberrations generated by the optical lens, and improve the imaging quality of the optical lens. The object side surface and the image side surface of the fifth lens are both convex, so that not only can the influence of coma aberration generated by the fifth lens on the optical lens be reduced, but also the spherical aberration of the optical lens can be corrected, 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 and the image side surface of the sixth lens are concave surfaces, so that edge view field light rays can be converged, the influence of coma aberration generated by the sixth lens on the optical lens can be reduced, and the imaging quality of the optical lens is improved.
In some embodiments, the seventh lens may have positive optical power, which is beneficial to suppressing the angle of incidence of the marginal field of view on the imaging surface, effectively transmitting more light beams to the imaging surface, and improving the imaging quality of the optical lens. The object side surface and the image side surface of the seventh lens are both convex, so that the influence of the coma aberration of the seventh lens on the optical lens is reduced, and the imaging quality of the optical lens is improved.
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, a diaphragm for limiting the light beam may be disposed between the fourth lens and the fifth lens, and the diaphragm may be disposed near the object side surface of the fifth lens, so that not only the generation of ghost images of the optical lens can be reduced, but also the range of the emergent light at the front end of the optical lens can be converged, and the caliber of the rear end of the optical lens can be reduced.
In some embodiments, the aperture value FNO of the optical lens satisfies: FNO is not less than 1.80. The range is satisfied, the large aperture characteristic is realized, and the definition of the image can be ensured in a low-light environment or at night.
In some embodiments, the maximum field angle FOV of the optical lens satisfies: the angle of the light source is less than or equal to 180 degrees. The wide-angle characteristic can be realized by meeting the range, so that more scene information can be acquired, and the requirement of large-range detection is met.
In some embodiments, the incidence angle CRA of the maximum field angle chief ray of the optical lens on the image plane satisfies: CRA is less than 9 DEG and less than 14 deg. The above range is satisfied, so that a larger tolerance error range exists between the CRA of the optical lens and the CRA of the chip photosensitive element, and the adaptation capability of the optical lens to the image sensor is improved.
In some embodiments, the optical total length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 8.0 and less than 13.0. 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 real image height IH corresponding to the maximum field angle satisfy: IH/f is more than 1.5 and less than 2.0. The wide-angle characteristic can be realized by meeting the range, so that the requirement of large-range shooting is met, the large-image-plane characteristic can be realized, and the imaging quality of the optical lens is improved.
In some embodiments, the maximum field angle FOV and aperture value FNO of the optical lens satisfy: FOV/FNO is less than 90 DEG and less than 110 deg. The above range is satisfied, which is advantageous to expand the angle of view of the optical lens and increase the aperture of the optical lens, realizing the characteristics of wide angle and large aperture. The realization of the wide-angle characteristic is favorable for the optical lens to acquire more scene information, meets the requirement of large-range detection, and is favorable for improving the problem of rapid decrease of the relative brightness of the edge view field caused by the wide angle, thereby being favorable for acquiring more scene information.
In some embodiments, the 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: 85 DEG < f X FOV/IH < 120 deg. The requirements of large-scale detection and high-quality imaging can be balanced, and the adaptability 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 first lens 1 The method meets the following conditions: -4.0 < f 1 And/f < 0. The first lens has appropriate negative focal power, which is favorable for moderating the refractive angle change of incident light, avoiding excessive aberration caused by too strong refractive change, and facilitating more light rays to enter the rear lightAnd the optical system increases the illumination and improves the imaging quality of the optical lens.
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 And/f < -150 >. The second lens can have proper negative focal power when the range is satisfied, and the influence of the second lens on the back focus offset under the high-low temperature condition can be reduced by reasonably limiting the focal power (such as smaller focal power) of the second lens, so that the temperature performance 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 third lens 3 The method meets the following conditions: -5.0 < f 3 And/f < -3.0. The range is satisfied, so that the third lens has proper negative focal power, the imaging area of the optical lens is increased, and the imaging quality of the optical lens is improved.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the fourth lens 4 The method meets the following conditions: f is more than 2.0 and less than 4 And/f is less than 4.0. The range is satisfied, so that the fourth lens has proper positive focal power, smooth transition of light trend is facilitated, and 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 Satisfy 0 < f 5 And/f is less than 1.80. The range is satisfied, so that the fifth lens has proper positive focal power, smooth transition of light trend is facilitated, and 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 sixth lens 6 The method meets the following conditions: -1.50 < f 6 And/f < 0. The range is satisfied, so that the sixth lens has proper negative focal power, the imaging area of the optical lens is increased, and the imaging quality of the optical lens is improved.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the seventh lens 7 The method meets the following conditions: f is 0 < f 7 And/f is less than 3.0. The seventh lens has proper positive focal power, which is beneficial to improving the light converging capability of the marginal view field, and further improving the relative illumination of the optical lens。
In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the first lens to the fourth lens 14 The method meets the following conditions: f is more than 4.0 and less than 14 And/f is less than 6.0. The range is satisfied, and the optical power of the first lens to the fourth lens is reasonably distributed, so that astigmatism and field curvature generated by the front lens of the optical lens are 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 combined focal lengths f of the fifth lens to the seventh lens 57 The method meets the following conditions: f is more than 2.0 and less than 57 And/f is less than 4.0. The range is met, the focal power of the fifth lens to the seventh lens is reasonably distributed, so that the spherical aberration and the coma aberration generated by the front end lens of the optical lens are balanced, and the imaging quality of the optical lens is 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: r is more than 1.0 and less than 3 /R 4 < 1.4. Satisfying the above range enables the second lens to adopt a lens shape close to concentric circles, which can reduce the optical path difference between the center and the periphery of the lens, and is favorable for correcting the distortion of the optical lens.
In some embodiments, the sum Σct of the total optical length TTL of the optical lens and the central thicknesses of the first lens to the seventh lens along the optical axis respectively satisfies: sigma CT/TTL is less than 0.6 and less than 0.8. The total length of the optical lens can be effectively compressed by meeting the range, and the structural design and the production process of the optical lens are facilitated.
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, G, H is the second, fourth, sixth, eighth, tenth, fourteen and sixteen 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 optical lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a stop ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.
The first lens element L1 has 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 convex, and an image-side surface S4 thereof is concave;
the third lens L3 has negative focal power, and both an object side surface S5 and an image side surface S6 of the third lens L are concave;
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;
a diaphragm ST;
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 both the object-side surface S11 and the image-side surface S12 thereof are concave;
the seventh lens L7 has positive focal power, and both an object side surface S13 and an image side surface S14 of the seventh lens L have convex surfaces;
the optical filter G1, the object side surface S15 and the image side surface S16 of which are plane surfaces;
a cover glass G2 having an object side surface S17 and an image side surface S18 both of which are planar;
the imaging surface S19 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
Fig. 2 shows a field curvature graph of example 1, in which the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane is represented by the horizontal axis representing the amount of shift (unit: mm) and the vertical axis representing the half field angle (unit: °). From the graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within +/-0.05 mm, which indicates that the optical lens can excellently correct the field curvature.
Fig. 3 shows a graph of relative illuminance for example 1, which represents relative illuminance values for different field angles on an imaging plane, with the horizontal axis representing half field angle (in: °), and the vertical axis representing relative illuminance (in:%). As can be seen from the figure, the relative illuminance value of the optical lens at the maximum half field angle is still greater than 70%, indicating that the optical lens has good relative illuminance.
Fig. 4 shows a Modulation Transfer Function (MTF) 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 present embodiment are all above 0.4 in the full field of view, in the range of 0 to 160lp/mm, the MTF curve is uniformly and smoothly reduced in the process from the center to the edge field of view, and the present embodiment has good imaging quality and good detail resolution at both low frequency and high frequency.
Fig. 5 shows an axial aberration diagram of example 1, which represents aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents an axial aberration value (unit: μm), and the vertical axis represents a normalized pupil radius. As can be seen from the figure, the axial aberration is controlled within ±35 μm, which means that the optical lens can correct axial aberration well.
Fig. 6 shows a vertical axis color difference graph of example 1, which shows color differences at different image heights on an imaging plane for each wavelength with respect to a center wavelength (0.55 μm), with the horizontal axis showing a vertical axis color difference value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis showing a normalized field angle. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-1 mu m, which shows that the optical lens can excellently correct chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.
Example 2
Referring to fig. 7, a schematic structural diagram of an optical lens provided in embodiment 2 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging plane along an optical axis: the optical lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a stop ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.
The first lens element L1 has 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 convex, and an image-side surface S4 thereof is concave;
the third lens L3 has negative focal power, and both an object side surface S5 and an image side surface S6 of the third lens L are concave;
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;
a diaphragm ST;
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 both the object-side surface S11 and the image-side surface S12 thereof are concave;
the seventh lens L7 has positive focal power, and both an object side surface S13 and an image side surface S14 of the seventh lens L have convex surfaces;
the optical filter G1, the object side surface S15 and the image side surface S16 of which are plane surfaces;
a cover glass G2 having an object side surface S17 and an image side surface S18 both of which are planar;
the imaging surface S19 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
Fig. 8 shows a field curvature graph of example 2, in which the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane is represented by the horizontal axis representing the amount of shift (unit: mm) and the vertical axis representing the half field angle (unit: °). From the graph, the field curvature of the meridian image plane and the sagittal image plane is controlled within +/-0.03 mm, which shows that the optical lens can excellently correct the field curvature.
Fig. 9 shows a graph of relative illuminance for example 2, which shows relative illuminance values for different field angles on an imaging plane, with the horizontal axis representing half field angle (in: °), and the vertical axis representing relative illuminance (in:%). As can be seen from the figure, the relative illuminance value of the optical lens at the maximum half field angle is still greater than 90%, indicating that the optical lens has excellent relative illuminance.
Fig. 10 shows a Modulation Transfer Function (MTF) 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 present embodiment are above 0.5 in the full field of view, and in the range of 0 to 160lp/mm, the MTF curve is uniformly and smoothly reduced in the process from the center to the edge field of view, and the MTF has excellent imaging quality and excellent detail resolution at both low frequency and high frequency.
Fig. 11 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 shift amount of the axial aberration is controlled within ±10μm, which indicates that the optical lens can satisfactorily correct the axial aberration.
Fig. 12 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 figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-1 mu m, which shows that the optical lens can excellently correct chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.
Example 3
Referring to fig. 13, a schematic structural diagram of an optical lens provided in embodiment 3 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging plane along an optical axis: the optical lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a stop ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.
The first lens element L1 has 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 convex, and an image-side surface S4 thereof is concave;
the third lens L3 has negative focal power, and both an object side surface S5 and an image side surface S6 of the third lens L are concave;
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;
a diaphragm ST;
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 both the object-side surface S11 and the image-side surface S12 thereof are concave;
the seventh lens L7 has positive focal power, and both an object side surface S13 and an image side surface S14 of the seventh lens L have convex surfaces;
the optical filter G1, the object side surface S15 and the image side surface S16 of which are plane surfaces;
a cover glass G2 having an object side surface S17 and an image side surface S18 both of which are planar;
the imaging surface S19 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
Fig. 14 shows a field curvature graph of example 3, in which the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane is represented by the horizontal axis representing the amount of shift (unit: mm) and the vertical axis representing the half 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 shows that the optical lens can excellently correct the field curvature.
Fig. 15 shows a graph of relative illuminance for example 3, which shows relative illuminance values for different field angles on an imaging plane, with the horizontal axis representing half field angle (in: °), and the vertical axis representing relative illuminance (in:%). As can be seen from the figure, the relative illuminance value of the optical lens at the maximum half field angle is still greater than 80%, indicating that the optical lens has excellent relative illuminance.
Fig. 16 shows a Modulation Transfer Function (MTF) 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 present embodiment are all above 0.4 in the full field of view, in the range of 0 to 160lp/mm, the MTF curve is uniformly and smoothly reduced in the process from the center to the edge field of view, and the present embodiment has good imaging quality and good detail resolution at both low frequency and high frequency.
Fig. 17 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 figure, the axial aberration is controlled within ±15 μm, which indicates that the optical lens can correct axial aberration well.
Fig. 18 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 figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-1 mu m, which shows that the optical lens can excellently correct chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.
Example 4
Referring to fig. 19, a schematic structural diagram of an optical lens provided in embodiment 4 of the present invention is shown, where the optical lens includes, in order from an object side to an imaging plane along an optical axis: the optical lens includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a stop ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an optical filter G1 and a cover glass G2.
The first lens element L1 has 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 convex, and an image-side surface S4 thereof is concave;
the third lens L3 has negative focal power, and both an object side surface S5 and an image side surface S6 of the third lens L are concave;
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;
a diaphragm ST;
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 both the object-side surface S11 and the image-side surface S12 thereof are concave;
the seventh lens L7 has positive focal power, and both an object side surface S13 and an image side surface S14 of the seventh lens L have convex surfaces;
the optical filter G1, the object side surface S15 and the image side surface S16 of which are plane surfaces;
a cover glass G2 having an object side surface S17 and an image side surface S18 both of which are planar;
the imaging surface S19 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
Fig. 20 shows a field curvature graph 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 represented by the horizontal axis representing the amount of shift (unit: mm) and the vertical axis representing 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 +/-0.04 mm, which shows that the optical lens can excellently correct the field curvature.
Fig. 21 shows a graph of relative illuminance of example 4, which represents relative illuminance values at different view angles on an imaging plane, with the horizontal axis representing half view angle (unit: °), and the vertical axis representing relative illuminance (unit:%). As can be seen from the figure, the relative illuminance value of the optical lens at the maximum half field angle is still greater than 80%, indicating that the optical lens has excellent relative illuminance.
Fig. 22 shows a Modulation Transfer Function (MTF) 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 present embodiment are all above 0.4 in the full field of view, in the range of 0 to 160lp/mm, the MTF curve is uniformly and smoothly reduced in the process from the center to the edge field of view, and the present embodiment has good imaging quality and good detail resolution at both low frequency and high frequency.
Fig. 23 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 axial aberration is controlled within ±25 μm, which means that the optical lens can correct axial aberration well.
Fig. 24 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 figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-2 mu m, which shows that the optical lens can excellently correct chromatic aberration of the marginal field of view and the 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 f-number FNO, the real image height IH, the field angle FOV and the numerical value corresponding to each condition in the above embodiments.
TABLE 5
In summary, the optical lens of the embodiment of the invention realizes the effects of large field of view, large aperture and miniaturization by reasonably matching the lens shape and focal power combination among the lenses.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (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;
a second lens element with negative refractive power having a convex object-side surface and a concave image-side surface;
a third lens having negative optical power; the object side surface and the image side surface are concave surfaces
A fourth lens element with positive refractive power having convex object-side and image-side surfaces;
a diaphragm;
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 concave object-side and image-side surfaces;
a seventh lens element with positive optical power having convex object-side and image-side surfaces;
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＜-150；
The effective focal length f of the optical lens and the distance from the first lens to the second lensCombined focal length f of the fourth lens 14 The method meets the following conditions: f is more than 4.0 and less than 14 /f＜6.0。
2. The optical lens of claim 1, wherein the optical total length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 8.0 and less than 13.0.
3. The optical lens according to claim 1, wherein the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: IH/f is more than 1.5 and less than 2.0.
4. The optical lens according to claim 1, wherein the maximum field angle FOV and aperture value FNO of the optical lens satisfy: FOV/FNO is less than 90 DEG and less than 110 deg.
5. 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: 85 DEG < f X FOV/IH < 120 deg.
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: -4.0 < f 1 /f＜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 seventh lens 7 The method meets the following conditions: f is 0 < f 7 /f＜3.0。
8. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a combined focal length f of the fifth lens to the seventh lens 57 The method meets the following conditions: f is more than 2.0 and less than 57 /f＜4.0。
9. The optical lens of claim 1, characterized in thatCharacterized in that 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: r is more than 1.0 and less than 3 /R 4 ＜1.4。
10. The optical lens according to claim 1, wherein a sum Σct of an optical total length TTL of the optical lens and center thicknesses of the first lens to the seventh lens along an optical axis, respectively, satisfies: sigma CT/TTL is less than 0.6 and less than 0.8.
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