CN115576084A - Optical lens - Google Patents
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- CN115576084A CN115576084A CN202211576010.0A CN202211576010A CN115576084A CN 115576084 A CN115576084 A CN 115576084A CN 202211576010 A CN202211576010 A CN 202211576010A CN 115576084 A CN115576084 A CN 115576084A
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- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/18—Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
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Abstract
The invention provides an optical lens, which comprises seven lenses in total, wherein the seven lenses are sequentially arranged from an object side to an imaging surface along an optical axis: a first lens having a negative optical power, both the object-side surface and the image-side surface of which are concave; the second lens with negative focal power, 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 a positive optical power; a diaphragm; the image side surface of the fourth lens is a convex surface; a fifth lens element having a positive refractive power, the object-side surface and the image-side surface of the fifth lens element being convex; a sixth lens element with negative refractive power having a concave object-side surface and a convex image-side surface; a seventh lens element having a negative refractive power, wherein both the object-side surface and the image-side surface are concave; the total optical length TTL and the effective focal length f of the optical lens meet the following requirements: TTL/f is more than 5.0 and less than 6.0. The optical lens has the advantages of large field of view, large aperture and miniaturization.
Description
Technical Field
The invention relates to the technical field of imaging lenses, in particular to an optical lens.
Background
With the development of automobile intelligence, the driving assistance function of the vehicle is gradually enhanced, wherein visual information collection is a core tool. With the improvement of the automatic driving level, the requirements on the vehicle-mounted camera are gradually increased, especially the front camera. The front camera can enhance the active safety and driver assistance functions, such as Automatic Emergency Braking (AEB), adaptive Cruise Control (ACC), lane Keeping Assist System (LKAS), traffic Jam Assist (TJA), and the like, and has the disadvantages of a large number of lenses, an excessively long optical total length, and the like while meeting the advantages of high resolution, a large field angle, good environmental adaptability, and the like, and is not beneficial to the miniaturization of an electronic system.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide an optical lens having advantages of a large field of view, a large aperture, and a small size.
In order to realize the purpose, the technical scheme of the invention is as follows:
an optical lens system comprises seven lenses, in order from an object side to an image plane along an optical axis:
a first lens element having a negative refractive power, both of an object-side surface and an image-side surface of the first lens element being concave;
a second lens with negative focal power, wherein 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 having positive refractive power, the object-side surface of which is convex;
a fifth lens element having a positive refractive power, the object-side surface and the image-side surface of the fifth lens element being convex;
a sixth lens element with negative refractive power having a concave object-side surface and a convex image-side surface;
a seventh lens element having a negative refractive power, wherein both the object-side surface and the image-side surface are concave;
the total optical length TTL and the effective focal length f of the optical lens meet the following requirements: TTL/f is more than 5.0 and less than 6.0.
Preferably, 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 1.6 and less than 2.0.
Preferably, the optical back focus BFL and the effective focal length f of the optical lens satisfy: 0.7 is less than BFL/f.
Preferably, the entrance pupil diameter EPD of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: IH/EPD is more than 2.5 and less than 3.0.
Preferably, the maximum field angle FO of the optical lensV, the real image height IH corresponding to the maximum field angle and the object side light-passing aperture D of the first lens 1 Satisfies the following conditions: d is more than 0.8 1 /IH/tan(FOV/2)＜0.9。
Preferably, the effective focal length f of the optical lens and the focal length f of the second lens are equal 2 Satisfies the following conditions: -8.0 < f 2 /f＜-4.0。
Preferably, the effective focal length f of the optical lens and the focal length f of the third lens element 3 Satisfies the following conditions: f is more than 6.0 3 /f＜8.0。
Preferably, the combined focal length f of the front diaphragm lens of the optical lens Front part Combined focal length f with diaphragm rear lens Rear end Satisfies the following conditions: -2.6 < f Front side /f Rear end ＜-1.9。
Preferably, the object side curvature radius R of the second lens 3 The image side surface curvature radius R of the second lens 4 And a center thickness CT of the second lens 2 Satisfies the following conditions: r is more than 0.3 3 /(R 4 +CT 2 )＜0.7。
Preferably, the total optical length TTL of the optical lens and the sum Σ CT of the central thicknesses of the first lens element to the seventh lens element along the optical axis satisfy: 0.5 < ∑ CT/TTL < 0.65.
Compared with the prior art, the invention has the beneficial effects that: the optical lens of the application combines with focal power through the lens shape between each lens of reasonable collocation, has realized possessing big visual field, big light ring and miniaturized advantage simultaneously.
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 above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic structural diagram of an optical lens system according to embodiment 1 of the present invention;
fig. 2 is a field curvature graph of the optical lens in embodiment 1 of the present invention;
FIG. 3 is a graph showing F-tan θ distortion of an optical lens in example 1 of the present invention;
fig. 4 is a graph showing a relative illuminance curve of the optical lens in embodiment 1 of the present invention;
fig. 5 is a MTF graph of the optical lens in embodiment 1 of the present invention;
fig. 6 is a graph showing axial aberration of the optical lens in embodiment 1 of the present invention;
fig. 7 is a vertical axis chromatic aberration curve diagram of the optical lens in embodiment 1 of the present invention;
fig. 8 is a schematic structural diagram of an optical lens system according to embodiment 2 of the present invention;
FIG. 9 is a graph of curvature of field of an optical lens in embodiment 2 of the present invention;
FIG. 10 is a graph showing F-tan θ distortion of an optical lens in example 2 of the present invention;
fig. 11 is a graph showing a relative illuminance of an optical lens in embodiment 2 of the present invention;
fig. 12 is a MTF graph of an optical lens in embodiment 2 of the present invention;
fig. 13 is a graph showing axial aberration of the optical lens in embodiment 2 of the present invention;
FIG. 14 is a vertical axis chromatic aberration diagram of an optical lens in embodiment 2 of the present invention;
fig. 15 is a schematic structural diagram of an optical lens system according to embodiment 3 of the present invention;
FIG. 16 is a graph of curvature of field of an optical lens in embodiment 3 of the present invention;
FIG. 17 is a graph showing F-tan θ distortion of an optical lens in embodiment 3 of the present invention;
fig. 18 is a graph showing a relative illuminance curve of the optical lens in embodiment 3 of the present invention;
fig. 19 is a MTF graph of an optical lens in embodiment 3 of the present invention;
FIG. 20 is a graph showing axial aberrations of an optical lens according to embodiment 3 of the present invention;
fig. 21 is a vertical axis chromatic aberration diagram of the optical lens in embodiment 3 of the present invention.
The following detailed description will further illustrate the invention 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 the detailed description is merely illustrative of embodiments of the application and does not limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.
It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens without departing from the teachings of the present invention.
In the drawings, the thickness, size and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and 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, it means that 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 called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.
It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" 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. Moreover, when a statement such as "at least one of" appears after a list of listed features, the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to examples or illustrations.
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 the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
The optical lens according to the embodiment of the present invention includes, in order from an object side to an image side: the lens comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens and a seventh lens.
In some embodiments, the first lens may have a negative power, which is beneficial for reducing the inclination angle of the incident light, thereby achieving effective sharing of a large field of view of the object. The object side surface and the image side surface of the first lens are both concave surfaces, so that the effective working caliber of the first lens can be reduced, and the overlarge caliber of the lens behind the optical lens caused by the excessive divergence of light rays can be avoided.
In some embodiments, the second lens element may have a negative focal power, and the negative focal power of the front end of the optical lens element can be shared, so that the problem that light is excessively deflected due to the excessively concentrated focal power of the first lens element is avoided, and the difficulty in correcting chromatic aberration of the optical lens element is reduced. 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, so that light rays emitted after passing through the first lens can be collected, the light ray trend is in stable transition, and the imaging quality of the optical lens is improved.
In some embodiments, the third lens element may have a positive focal power, which is advantageous for converging light rays and reducing the deflection angle of the light rays, so that the light rays are smoothly transitioned.
In some embodiments, the fourth lens element may have a positive focal power, which is beneficial for converging light rays and reducing the deflection angle of the light rays, so that the light rays are in smooth transition. The object side surface of the fourth lens is a convex surface, so that the light focusing position reflected by the object side surface of the fourth lens is positioned behind the image side surface, the design ghost of the optical lens is effectively improved, and the imaging quality of the optical lens is improved.
In some embodiments, the fifth lens element may have a positive focal power, which is beneficial for converging light rays and reducing the deflection angle of the light rays, so that the light rays are in smooth transition. The object side surface and the image side surface of the fifth lens are convex surfaces, so that light rays in an edge field of view can be converged, the converged light rays can smoothly enter a rear-end optical system, the influence of the coma aberration of the fifth lens on the optical lens can be reduced, and the imaging quality of the optical lens is improved.
In some embodiments, the sixth lens element may have a negative focal power, which is beneficial to increase an imaging area of the optical lens and improve the imaging quality of the optical lens. The object side surface of the sixth lens is a concave surface, the image side surface of the sixth lens is a convex surface, and therefore light rays in the edge field of view can be converged, the converged light rays can smoothly enter the rear-end optical system, the field curvature generated by the sixth lens can be reduced, and the imaging quality of the optical lens is improved.
In some embodiments, the seventh lens has negative focal 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 seventh lens are both concave surfaces, and light rays of a central view field can be converged, so that the total length of the optical lens is compressed.
In some embodiments, the fifth lens and the sixth lens can be cemented to form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce eccentricity sensitivity of the optical lens, balance aberration of the optical lens, and improve imaging quality of the optical lens; the assembly sensitivity of the optical lens can be reduced, the processing 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 third lens and the fourth lens, and the diaphragm may be disposed near an object-side surface of the fourth lens, which can reduce generation of ghost images of the optical lens, and is beneficial to converging light entering the optical system and reducing a rear aperture of the optical lens.
In some embodiments, the aperture value FNO of the optical lens satisfies: FNO is less than or equal to 1.60. The range is satisfied, the large aperture characteristic is favorably realized, and the image definition can be ensured in a low-light environment or at night.
In some embodiments, the maximum field angle FOV of the optical lens satisfies: 110 < FOV < 130. The wide-angle detection method has the advantages that the wide-angle characteristic is favorably realized, more scene information can be acquired, and the requirement of large-range detection is met.
In some embodiments, the total optical length TTL and the effective focal length f of the optical lens satisfy: TTL/f is more than 5.0 and less than 6.0. The optical lens can effectively limit the length of the lens and realize the miniaturization of the optical lens.
In some embodiments, the real image height IH corresponding to the maximum field angle and the effective focal length f of the optical lens satisfy: IH/f is more than 1.6 and less than 2.0. Satisfying the above range can make the optical lens not only give consideration to the characteristics of a large image plane, but also have good imaging quality.
In some embodiments, the optical back focus BFL and the effective focal length f of the optical lens satisfy: 0.7 is less than BFL/f. The method meets the range, is favorable for obtaining balance between good imaging quality and optical back focal length easy to assemble, and reduces the difficulty of the camera module assembly process while ensuring the imaging quality of the optical lens.
In some embodiments, the real image height IH of the optical lens corresponding to the maximum field angle and the entrance pupil diameter EPD satisfy: IH/EPD is more than 2.5 and less than 3.0. The width of the light ray bundle entering the optical lens can be increased, so that the brightness of the optical lens at the image surface is improved, and the dark corner is avoided.
In some embodiments, the maximum field angle FOV of the optical lens, the real image height IH corresponding to the maximum field angle, and the first lens object-side clear aperture D 1 Satisfies the following conditions: d is more than 0.8 1 /IH/tan(FOV/2)＜0.9。The optical lens has a large field angle and a large image plane, and the front port diameter is small, so that the optical lens is miniaturized.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the first lens are different 1 Satisfies the following conditions: -4.0 < f 1 And/f is less than-2.0. Satisfying above-mentioned scope, can making first lens have appropriate negative power, be favorable to incident light refraction angle change comparatively milder, avoid refraction change too strong and produce too much aberration, help more light to get into rear optical system simultaneously, increase the illumination and promote optical lens's image quality.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the second lens 2 Satisfies the following conditions: -8.0 < f 2 And/f < -4.0. Satisfying the above range, the second lens can have a proper negative focal power, and can share the negative focal power of the front end of the optical lens, thereby being beneficial to avoiding the overlarge light deflection caused by the over-concentration of the focal power of the first lens.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the third lens are 3 Satisfies the following conditions: f is more than 6.0 3 The/f is less than 8.0. Satisfying above-mentioned scope, can making the third lens have appropriate positive focal power, be favorable to assembling light and reduce light deflection angle simultaneously, let the light trend smooth transition, promote optical lens's the formation of image quality.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the fourth lens are different 4 Satisfies the following conditions: f is more than 0 4 The/f is less than 3.0. Satisfying above-mentioned scope, can making the fourth lens have appropriate positive focal power, be favorable to gathering reducing light deflection angle when light, let the light trend smooth transition, promote optical lens's the formation of image quality.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the fifth lens 5 Satisfies the following conditions: f is more than 0 5 The/f is less than 2.0. Satisfying above-mentioned scope, can making the fifth lens have appropriate positive focal power, be favorable to gathering light and reducing light deflection angle simultaneously, let the light trend smooth transition, promote optical lens's the formation of image quality.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the sixth lens element 6 Satisfies the following conditions: -2.5 < f 6 The/f is less than 0. The sixth lens has appropriate negative focal power, so that the spherical aberration of the fifth lens can be balanced, the chromatic aberration of the optical lens can be corrected, and the imaging quality of the optical lens can be improved.
In some embodiments, the effective focal length f of the optical lens and the focal length f of the seventh lens 7 Satisfies the following conditions: -2.5 < f 7 The/f is less than 0. The seventh lens has appropriate negative focal power, so that the imaging area of the optical lens can be increased, and the imaging quality of the optical lens can be improved.
In some embodiments, the combined focal length f of the front stop lens of the optical lens Front side Combined focal length f with diaphragm rear lens Rear end Satisfies the following conditions: -2.6 < f Front part /f Rear end < -1.9. The optical lens system meets the range, can distribute the combined focal length ratio of the lens behind the diaphragm to be slightly larger than that of the lens in front of the diaphragm, and is favorable for miniaturization of the optical lens.
In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the fifth lens and the sixth lens 56 Satisfies the following conditions: 2.0 < f 56 The/f is less than 3.5. The sensitivity of the optical lens can be reduced and the imaging quality of the optical lens can be improved.
In some embodiments, the radius of curvature R of the object-side surface of the first lens 1 Radius of curvature R with image side 2 Satisfies the following conditions: -12.0 < R 1 /R 2 < -6.0. The curvature radius of the object side of the first lens is larger, the correction difficulty of the optical lens on astigmatism and distortion can be reduced, and the imaging quality of the optical lens is improved.
In some embodiments, the radius of curvature R of the image-side surface of the first lens 2 Radius of curvature R of object side surface of second lens 3 Satisfies the following conditions: -1.7 < R 2 /R 3 < -0.9. Satisfying the above range, the image-side surface of the first lens element and the object-side surface of the second lens element can be made to have a symmetrical surface shape, which is advantageous for balancing the third lens element and the fourth lens elementComa aberration improves the imaging quality of the optical lens.
In some embodiments, the second lens has an object-side radius of curvature R 3 The radius of curvature R of the image side surface of the second lens element 4 Center thickness CT of the second lens 2 Satisfies the following conditions: r is more than 0.3 3 /(R 4 +CT 2 ) Is less than 0.7. The second lens is a thick meniscus lens, so that the field curvature correction characteristic is realized, and the correction of the aberration of the whole optical lens is facilitated.
In some embodiments, the total optical length TTL of the optical lens and the sum Σ CT of the central thicknesses of the first lens to the seventh lens along the optical axis, respectively, satisfy: 0.5 < ∑ CT/TTL < 0.65. The optical lens structure meets the range, can effectively compress the total length of the optical lens, and is beneficial to the structural design and the production process of the optical lens.
In order to make the system have better optical performance, a plurality of aspheric lenses are adopted in the lens, and the surface shapes of the aspheric surfaces of the optical lens satisfy the following equation:
wherein z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance between the optical axis and the curved surface, c is the curvature of the vertex of the curved surface, K is the coefficient of the quadric surface, and A, B, C, D, E, F are the coefficients of the second order, the fourth order, the sixth order, the eighth order, the tenth order and the twelfth order curved surface respectively.
The invention is further illustrated below in the following examples. In various embodiments, the thickness, the curvature radius, and the material selection part of each lens in the optical lens are different, and specific differences can be referred to the parameter tables of the various embodiments. The following examples are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following examples, and any other changes, substitutions, combinations or simplifications which do not depart from the innovative points of the present invention should be construed as being equivalent substitutions and shall be included within the scope of the present invention.
Example 1
Referring to fig. 1, a schematic structural diagram of an optical lens system according to embodiment 1 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter G1, and a cover glass G2.
The first lens L1 has negative focal power, and the object side surface S1 and the image side surface S2 are both concave surfaces;
the second lens L2 has negative focal power, the object side surface S3 is a concave surface, and the image side surface S4 is a convex surface;
the third lens L3 has positive focal power, and the object side surface S5 is a convex surface, and the image side surface S6 is a concave surface;
a diaphragm ST;
the fourth lens L4 has positive focal power, and both the object side surface S7 and the image side surface S8 are convex surfaces;
the fifth lens L5 has positive focal power, and both the object side surface S9 and the image side surface S10 are convex surfaces;
the sixth lens element L6 has negative focal power, and has a concave object-side surface S11 and a convex image-side surface S12;
the seventh lens L7 has negative power, and both the object-side surface S13 and the image-side surface S14 are concave;
the fifth lens L5 and the sixth lens L6 can be glued to form a cemented lens;
the object side surface S15 and the image side surface S16 of the optical filter G1 are both planes;
the object side surface S17 and the image side surface S18 of the protective glass G2 are both planes;
the image formation surface S19 is a plane.
Relevant parameters of each lens in the optical lens in embodiment 1 are shown in table 1-1.
TABLE 1-1
The surface shape parameters of the aspherical lens of the optical lens in example 1 are shown in table 1-2.
Tables 1 to 2
In this embodiment, the curvature of field curve, F-tan θ distortion, relative illumination, MTF, axial aberration, and homeotropic aberration of the optical lens are shown in fig. 2, 3, 4, 5, 6, and 7, respectively.
Fig. 2 shows a field curvature 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, with the horizontal axis indicating a shift amount (unit: mm) and the vertical axis indicating a half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional 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. 3 shows an F-tan θ distortion curve of example 1, which shows F-tan θ distortions at different image heights on an image forming plane for light rays of different wavelengths, with the abscissa representing the F-tan θ distortion (unit:%) and the ordinate representing the half field angle (unit: °). As can be seen from the figure, the F-tan theta distortion of the optical lens is controlled within +/-50%, and the trend of the F-tan theta distortion curve is smooth, so that the definition of an expanded image is effectively improved, and the optical lens can better correct the F-tan theta distortion.
Fig. 4 shows a relative illuminance curve of example 1, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °) and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative luminance value of the optical lens is still greater than 60% at the maximum half field angle, which indicates that the optical lens has better relative luminance.
Fig. 5 shows MTF (modulation transfer function) graphs of embodiment 1, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. As can be seen from the figure, the MTF value of the embodiment is 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 from the center to the edge field of view, and the image quality and the detail resolution capability are good under the conditions of low frequency and high frequency.
Fig. 6 shows an axial aberration curve of example 1, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the amount of shift of the axial aberration is controlled within ± 15 μm, indicating that the optical lens can correct the axial aberration well.
Fig. 7 shows a vertical axis chromatic aberration curve of example 1, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.55 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-1 μm, which shows that the optical lens can excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.
Example 2
Referring to fig. 8, a schematic structural diagram of an optical lens system according to embodiment 2 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter G1, and a cover glass G2.
The first lens L1 has negative focal power, and both the object side surface S1 and the image side surface S2 are concave surfaces;
the second lens L2 has negative focal power, the object side surface S3 is a concave surface, and the image side surface S4 is a convex surface;
the third lens L3 has positive focal power, and the object side surface S5 is a concave surface, and the image side surface S6 is a convex surface;
a diaphragm ST;
the fourth lens L4 has positive focal power, and the object side surface S7 is a convex surface, and the image side surface S8 is a concave surface;
the fifth lens L5 has positive focal power, and both the object side surface S9 and the image side surface S10 are convex surfaces;
the sixth lens element L6 has negative focal power, and has a concave object-side surface S11 and a convex image-side surface S12;
the seventh lens L7 has negative power, and both the object-side surface S13 and the image-side surface S14 are concave;
the fifth lens L5 and the sixth lens L6 may be cemented to constitute a cemented lens.
The relevant parameters of each lens in the optical lens in embodiment 2 are shown in table 2-1.
TABLE 2-1
The parameters of the surface shape of the aspherical lens of the optical lens in example 2 are shown in table 2-2.
Tables 2 to 2
In this embodiment, the curvature of field curve, F-tan θ distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens are respectively shown in fig. 9, 10, 11, 12, 13, and 14.
Fig. 9 shows a field curvature curve of example 2, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of displacement (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional 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. 10 shows an F-tan θ distortion curve of example 2, which shows F-tan θ distortions at different image heights on an image forming plane for light rays of different wavelengths, with the abscissa representing the F-tan θ distortion (unit:%) and the ordinate representing the half field angle (unit: °). As can be seen from the figure, the F-tan theta distortion of the optical lens is controlled within +/-50%, and the trend of the F-tan theta distortion curve is smooth, so that the definition of an expanded image is effectively improved, and the optical lens can better correct the F-tan theta distortion.
Fig. 11 shows a relative illuminance curve of example 2, which represents relative illuminance values at different angles of field of view on an imaging plane, with the horizontal axis representing a half field angle (unit: °) and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative luminance value of the optical lens is still greater than 50% at the maximum half field angle, which indicates that the optical lens has better relative luminance.
Fig. 12 shows MTF (modulation transfer function) graphs of embodiment 2, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.3 in the whole field of view, and in the range of 0-160 lp/mm, the MTF curve uniformly and smoothly drops in the process of the field of view from the center to the edge, and the MTF has better imaging quality and better detail resolution capability under the conditions of low frequency and high frequency.
Fig. 13 shows an axial aberration curve of example 2, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the shift amount of the axial aberration is controlled within ± 30 μm, which indicates that the optical lens can correct the axial aberration well.
Fig. 14 shows a vertical axis chromatic aberration curve of example 2, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.55 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-2 μm, which shows that the optical lens can excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.
Example 3
Referring to fig. 15, a schematic structural diagram of an optical lens system according to embodiment 3 of the present invention is shown, the optical lens system sequentially includes, from an object side to an image plane along an optical axis: a first lens L1, a second lens L2, a third lens L3, a stop ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an optical filter G1, and a cover glass G2.
The first lens L1 has negative focal power, and the object side surface S1 and the image side surface S2 are both concave surfaces;
the second lens L2 has negative focal power, the object side surface S3 is a concave surface, and the image side surface S4 is a convex surface;
the third lens L3 has positive focal power, and the object side surface S5 and the image side surface S6 are both convex surfaces;
a diaphragm ST;
the fourth lens L4 has positive focal power, and the object side surface S7 is a convex surface, and the image side surface S8 is a concave surface;
the fifth lens L5 has positive focal power, and both the object side surface S9 and the image side surface S10 are convex surfaces;
the sixth lens element L6 has negative focal power, and has a concave object-side surface S11 and a convex image-side surface S12;
the seventh lens L7 has negative power, and both the object-side surface S13 and the image-side surface S14 are concave;
the fifth lens L5 and the sixth lens L6 may be cemented to constitute a cemented lens.
The relevant parameters of each lens in the optical lens in example 3 are shown in table 3-1.
TABLE 3-1
The parameters of the surface shape of the aspherical lens of the optical lens in example 3 are shown in table 3-2.
TABLE 3-2
In the present embodiment, a field curvature graph, an F-tan θ distortion curve, a relative illuminance graph, an MTF graph, an axial aberration graph, and a vertical axis chromatic aberration graph of the optical lens are shown in fig. 16, 17, 18, 19, 20, and 21, respectively.
Fig. 16 shows a field curvature curve of example 3, which shows the degree of curvature of light rays of different wavelengths on a meridional image plane and a sagittal image plane, with the horizontal axis representing the amount of displacement (unit: mm) and the vertical axis representing the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional 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. 17 shows an F-tan θ distortion curve of example 3, which shows F-tan θ distortions at different image heights on an image forming plane for light rays of different wavelengths, with the abscissa representing the F-tan θ distortion (unit:%) and the ordinate representing the half field angle (unit: °). As can be seen from the figure, the F-tan theta distortion of the optical lens is controlled within +/-50%, and the trend of the F-tan theta distortion curve is smooth, so that the definition of an expanded image is effectively improved, and the optical lens can better correct the F-tan theta distortion.
Fig. 18 shows a relative illuminance curve of example 3, which represents relative illuminance values at different angles of field of view on the imaging plane, with the horizontal axis representing the half field angle (unit: °), and the vertical axis representing the relative illuminance (unit:%). As can be seen from the figure, the relative luminance value of the optical lens is still greater than 50% at the maximum half field angle, which indicates that the optical lens has better relative luminance.
Fig. 19 shows MTF (modulation transfer function) graphs of embodiment 3, which represent the degree of modulation of lens imaging at different spatial frequencies for each field of view, with the horizontal axis representing the spatial frequency (unit: lp/mm) and the vertical axis representing the MTF value. As can be seen from the figure, the MTF value of the embodiment is 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 from the center to the edge field of view, and the image quality and the detail resolution capability are good under the conditions of low frequency and high frequency.
Fig. 20 shows an axial aberration curve of example 3, which represents the aberration on the optical axis at the imaging plane for each wavelength, with the horizontal axis representing the axial aberration value (unit: μm) and the vertical axis representing the normalized pupil radius. As can be seen from the figure, the amount of shift of the axial aberration is controlled within ± 20 μm, indicating that the optical lens can correct the axial aberration well.
Fig. 21 shows a vertical axis chromatic aberration curve of example 3, which shows chromatic aberration at different image heights on an image forming plane for each wavelength with respect to a center wavelength (0.55 μm), the horizontal axis shows a vertical axis chromatic aberration value (unit: μm) for each wavelength with respect to the center wavelength, and the vertical axis shows a normalized angle of view. As can be seen from the figure, the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within +/-2 μm, which shows that the optical lens can excellently correct the chromatic aberration of the marginal field of view and the secondary spectrum of the whole image surface.
Please refer to table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the aperture FNO, the real image height IH, and the maximum field angle FOV of the optical lens, and the values corresponding to each conditional expression in the embodiments.
TABLE 4
In summary, the optical lens of the embodiment of the invention realizes the advantages of large field of view, large aperture and miniaturization by reasonably matching the combination of the lens shape and the focal power among the lenses.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean 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 invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. 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 above examples are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. An optical lens system comprising seven lens elements, in order from an object side to an image plane along an optical axis:
a first lens element having a negative refractive power, both of an object-side surface and an image-side surface of the first lens element being concave;
the second lens with negative focal power, 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 a positive optical power;
a diaphragm;
a fourth lens having a positive refractive power, an object-side surface of which is convex;
a fifth lens element having positive refractive power, both the object-side surface and the image-side surface of the fifth lens element being convex;
a sixth lens element with negative refractive power having a concave object-side surface and a convex image-side surface;
a seventh lens element having a negative refractive power, wherein both the object-side surface and the image-side surface are concave;
the total optical length TTL and the effective focal length f of the optical lens meet the following requirements: TTL/f is more than 5.0 and less than 6.0.
2. The optical lens according to claim 1, wherein a real image height IH of the optical lens corresponding to an effective focal length f and a maximum field angle satisfies: IH/f is more than 1.6 and less than 2.0.
3. An optical lens according to claim 1, characterized in that the optical back focus BFL and the effective focal length f of the optical lens satisfy: 0.7 is less than BFL/f.
4. The optical lens of claim 1, wherein an entrance pupil diameter EPD of the optical lens satisfies a real image height IH corresponding to a maximum field angle: IH/EPD is more than 2.5 and less than 3.0.
5. The optical lens of claim 1, wherein the maximum field angle FOV of the optical lens, the real image height IH corresponding to the maximum field angle, and the object-side clear aperture D of the first lens 1 Satisfies the following conditions: d is more than 0.8 1 /IH/tan(FOV/2)＜0.9。
6. The method of claim 1Characterized in that the effective focal length f of the optical lens and the focal length f of the second lens are equal 2 Satisfies the following conditions: -8.0 < f 2 /f＜-4.0。
7. An optical lens according to claim 1, characterized in that the effective focal length f of the optical lens and the focal length f of the third lens are 3 Satisfies the following conditions: f is more than 6.0 3 /f＜8.0。
8. An optical lens according to claim 1, characterized in that the combined focal length f of the front stop lens of the optical lens Front side Combined focal length f with diaphragm rear lens Rear end Satisfies the following conditions: -2.6 < f Front side /f Rear end ＜-1.9。
9. An optical lens as recited in claim 1, characterized in that the object-side radius of curvature R of the second lens 3 The image side surface curvature radius R of the second lens 4 And a center thickness CT of the second lens 2 Satisfies the following conditions: r is more than 0.3 3 /(R 4 +CT 2 )＜0.7。
10. An optical lens according to claim 1, wherein a total optical length TTL of the optical lens and a sum Σ CT of central thicknesses of the first lens to the seventh lens along an optical axis, respectively, satisfy: 0.5 < ∑ CT/TTL < 0.65.
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| CN116184640A (en) * | 2023-05-04 | 2023-05-30 | 江西联创电子有限公司 | Optical lens |
| CN116203705A (en) * | 2023-05-04 | 2023-06-02 | 江西联创电子有限公司 | Optical lens |
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| CN112596215A (en) * | 2021-03-02 | 2021-04-02 | 江西联益光学有限公司 | Optical lens and imaging apparatus |
| CN113495342A (en) * | 2020-04-02 | 2021-10-12 | 宁波舜宇车载光学技术有限公司 | Optical lens and electronic device |
| CN114384666A (en) * | 2020-10-19 | 2022-04-22 | 宁波舜宇车载光学技术有限公司 | Optical lens and electronic device |
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| JP2008015418A (en) * | 2006-07-10 | 2008-01-24 | Nikon Vision Co Ltd | Eyepiece |
| CN113495342A (en) * | 2020-04-02 | 2021-10-12 | 宁波舜宇车载光学技术有限公司 | Optical lens and electronic device |
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| CN116203705B (en) * | 2023-05-04 | 2023-09-12 | 江西联创电子有限公司 | optical lens |
| CN116184640B (en) * | 2023-05-04 | 2023-09-12 | 江西联创电子有限公司 | optical lens |
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