Optical lens

Abstract

The application provides an optical lens, which comprises seven lenses in sequence along an optical axis from an object side to an imaging surface, and the seven lenses comprise: a first lens with negative optical power, wherein an image side of the first lens is a concave surface; a second lens with negative optical power, wherein an object side of the second lens is a convex surface, and an image side of the second lens is a concave surface; a third lens with positive optical power, wherein an object side of the third lens is a convex surface, and an image side of the third lens is a convex surface; a fourth lens with positive optical power, wherein an object side of the fourth lens is a convex surface, and an image side of the fourth lens is a convex surface; a fifth lens with positive optical power, wherein an image side of the fifth lens is a convex surface; a sixth lens with negative optical power, wherein an object side of the sixth lens is a concave surface, and an image side of the sixth lens is a concave surface; and a seventh lens with negative optical power, wherein an object side of the seventh lens is a convex surface near the optical axis, and an image side of the seventh lens is a concave surface near the optical axis. The optical lens provided by the application can improve the imaging quality of the optical lens and has the advantage of excellent imaging quality through specific surface shape matching and reasonable optical power distribution.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of imaging lenses, in particular to an optical lens. BACKGROUND

[0002] With the rapid development of unmanned aerial vehicles, security and protection, and automobiles, the pursuit of imaging effects of lenses mounted thereon is also more diversified. At present, unmanned aerial vehicles develop rapidly, and win the favor of consumers with their unique high-altitude perspective and wide shooting pictures. The demand for optical lenses matched with them is also increasing. The optical lenses mounted thereon not only require high-definition image quality, but also require to present larger local details to realize that high-altitude view can also present local details in detail and shoot local close-up pictures.

[0003] Therefore, it is necessary to develop an optical lens with a large image surface, a large aperture, and good imaging effect, so as to better meet the market demand. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide an optical lens with the advantages of excellent imaging quality.

[0005] The present application provides an optical lens, which comprises seven lenses in sequence along the optical axis from the object side to the imaging surface:

[0006] The first lens with negative focal power has a concave image side surface;

[0007] The second lens with negative focal power has a convex object side surface and a concave image side surface;

[0008] The third lens with positive focal power has a convex object side surface and a convex image side surface;

[0009] The fourth lens with positive focal power has a convex object side surface and a convex image side surface;

[0010] The fifth lens with positive focal power has a convex image side surface;

[0011] The sixth lens with negative focal power has a concave object side surface and a concave image side surface;

[0012] The seventh lens with negative focal power has a convex object side surface near the optical axis and a concave image side surface near the optical axis;

[0013] Wherein, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 3.8 < TTL / f < 3.9.

[0014] It is further preferred that the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens and the real image height IH corresponding to the maximum field of view FOV of the optical lens satisfy: 45° < (f x FOV) / IH < 46°.

[0015] It is further preferred that the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.1 < f1 / f < -2.

[0016] It is further preferred that the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 2 < f4 / f < 2.5.

[0017] It is further preferred that the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2 < f6 / f < -1.3.

[0018] It is further preferred that the object side surface radius of curvature R13 of the seventh lens and the image side surface radius of curvature R14 of the seventh lens satisfy: 1.6 < R13 / R14 < 28.

[0019] It is further preferred that the object side surface radius of curvature R1 of the first lens and the image side surface radius of curvature R2 of the first lens satisfy: 0.8 < (R1 + R2) / (R1 - R2) < 1.25.

[0020] It is further preferred that the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.5 < f5 / f6 < -1.4.

[0021] It is further preferred that the sum of the central thicknesses of the first lens to the seventh lens along the optical axis respectively ∑CT and the total optical length TTL of the optical lens satisfy: 0.55 < ∑CT / TTL < 0.65.

[0022] It is further preferred that the real image height IH corresponding to the maximum field of view of the optical lens and the aperture value Fno of the optical lens satisfy: 3.7 mm < IH / Fno < 3.8 mm.

[0023] Compared with the prior art, the optical lens provided by the present application adopts seven lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages of miniaturization, large aperture, large field of view, small distortion, high resolution and high imaging quality. BRIEF DESCRIPTION OF DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings in which:

[0025] Figure 1 Structure diagram of the optical lens in Embodiment 1 of the present application.

[0026] Figure 2 F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 1 of the present application.

[0027] Figure 3 Curvature diagram of the optical lens in Embodiment 1 of the present application.

[0028] Figure 4 Relative luminance curve diagram of the optical lens in Embodiment 1 of the present application.

[0029] Figure 5 MTF curve diagram of the optical lens in Embodiment 1 of the present application.

[0030] Figure 6 Structure diagram of the optical lens in Embodiment 2 of the present application.

[0031] Figure 7 F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 2 of the present application.

[0032] Figure 8 Curvature diagram of the optical lens in Embodiment 2 of the present application.

[0033] Figure 9 Relative luminance curve diagram of the optical lens in Embodiment 2 of the present application.

[0034] Figure 10 MTF curve diagram of the optical lens in Embodiment 2 of the present application.

[0035] Figure 11 Structure diagram of the optical lens in Embodiment 3 of the present application.

[0036] Figure 12 F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 3 of the present application.

[0037] Figure 13 Curvature diagram of the optical lens in Embodiment 3 of the present application.

[0038] Figure 14 Relative luminance curve diagram of the optical lens in Embodiment 3 of the present application.

[0039] Figure 15 MTF curve diagram of the optical lens in Embodiment 3 of the present application.

[0040] The following detailed description will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0041] For a better understanding of the present application, various aspects of the present application will be described in more detail below with reference to the accompanying drawings. It is to be noted that these details are merely exemplary of the embodiments of the present application and are intended to provide a more detailed description of the application as claimed. Throughout the specification, like drawing reference numbers will be understood to refer to like parts throughout the specification and the claims. The expression "and / or" encompasses any and all combinations of one or more of the associated listed items.

[0042] It is noted that, in this specification, the terms first, second, third, etc. are merely used to distinguish one feature from another, and do not denote any limitation of the features. Thus, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0043] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for the sake of explanation. Specifically, the shape of the spherical surface or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or aspherical surface is not limited to the shape of the spherical surface or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0044] In this specification, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, 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 surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0045] It is also to be understood that the use of the terms "include", "includes", "including", "comprise", "comprises", "comprising", "have", "has", "having", or "contains" or "containing", when used in this specification, means that there are other features, elements, or components that are not listed, but are present in addition to those listed. In addition, when the expressions such as "at least one of... " appear after a list of one or more features, it modifies the entire list of features and does not modify the individual elements of the list. Furthermore, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application." Also, the term "exemplary" is intended to mean an example or an illustration.

[0046] 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.

[0047] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0048] The optical lens provided by the embodiment of the present application comprises seven lenses, which are sequentially arranged along the optical axis from the object side to the imaging surface and include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens.

[0049] In some embodiments, the first lens can have a negative focal power, the object side surface thereof can be a concave surface or a convex surface, and the image side surface thereof is a concave surface. The second lens can have a negative focal power, the object side surface thereof is a convex surface, and the image side surface thereof is a concave surface. The third lens can have a positive focal power, the object side surface thereof is a convex surface, and the image side surface thereof is a convex surface. The fourth lens can have a positive focal power, the object side surface thereof is a convex surface, and the image side surface thereof is a convex surface. The fifth lens can have a positive focal power, the object side surface thereof can be a concave surface or a convex surface, and the image side surface thereof is a convex surface. The sixth lens can have a negative focal power, the object side surface thereof is a concave surface, and the image side surface thereof is a concave surface. The seventh lens can have a negative focal power, the object side surface thereof is a convex surface near the optical axis, and the image side surface thereof is a concave surface near the optical axis.

[0050] In some embodiments, the optical lens can further comprise a diaphragm, which can be located between the third lens and the fourth lens. It can be understood that the diaphragm is used to limit the amount of light to change the brightness of the imaging.

[0051] In some embodiments, the optical lens can further comprise a filter, which is arranged between the seventh lens and the imaging surface. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0052] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 3.8 < TTL / f < 3.9. Satisfying the above condition, the length of the lens can be effectively limited, which is beneficial to realize the miniaturization of the optical lens.

[0053] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 45° < (f x FOV) / IH < 46°. Satisfying the above condition, by reasonably limiting the relationship among the focal length, the field of view and the image height of the optical lens, the balance between the field of view and the imaging surface of the optical lens is realized, which better meets the use requirement of high image quality and wide-angle shooting in the outdoor environment of the unmanned aerial vehicle.

[0054] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.1 < f1 / f < -2. The first lens adopts negative refractive power to regulate the light path, and the effective focal length of the first lens is reasonably set to improve the field of view of the imaging system.

[0055] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 2 < f4 / f < 2.5. The fourth lens adopts positive refractive power to further focus light and optimize imaging quality, and corrects residual aberrations (such as distortion, chromatic aberration, etc.), thereby ensuring imaging clarity and color reproduction.

[0056] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2 < f6 / f < -1.3. The sixth lens has negative refractive power to reduce the diameter of the light beam and the size of the subsequent lens group.

[0057] In some embodiments, the object side radius of curvature R13 of the seventh lens and the image side radius of curvature R14 of the seventh lens satisfy: 1.6 < R13 / R14 < 28. The radius of curvature of the seventh lens is reasonably set to correct the aberration of the optical lens and reduce the tolerance sensitivity of the optical lens.

[0058] In some embodiments, the object side radius of curvature R1 of the first lens and the image side radius of curvature R2 of the first lens satisfy: 0.8 < (R1+R2) / (R1-R2) < 1.25. The object side radius of curvature and the image side radius of curvature of the first lens at the near optical axis are reasonably controlled, thereby facilitating the control of the shape of the first lens, correcting the aberration generated by itself, and improving the imaging quality.

[0059] In some embodiments, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.5 < f5 / f6 < -1.4. The fifth lens and the sixth lens have opposite refractive powers to enable the optical system to have a good ability to balance aberrations.

[0060] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis and the total optical length TTL of the optical lens satisfy: 0.55 < ∑CT / TTL < 0.65. The total length of the optical lens is effectively compressed, and the structure design and production process of the optical lens are facilitated.

[0061] In some embodiments, a real image height IH corresponding to a maximum field of view angle of the optical lens and an aperture value Fno of the optical lens satisfy: 3.7mm<IH / Fno<3.8mm. By satisfying the above condition, the optical lens has a large image surface while having a large aperture, achieving a balance between a large image surface and a large aperture.

[0062] In some embodiments, a real image height IH corresponding to a maximum field of view angle of the optical lens and an effective focal length f of the optical lens satisfy: 2.05<IH / f<2.1. By satisfying the above condition, a large field of view angle and imaging range can be achieved, which can ensure the depth of field of the optical lens while achieving a large image surface characteristic, thereby improving the imaging quality of the optical system.

[0063] In some embodiments, an optical total length TTL of the optical lens and an effective focal length f of the optical lens satisfy: 1.85<TTL / IH<1.9. By satisfying the above condition, the miniaturization of the lens can be better achieved, while ensuring that the lens has a large image surface under the condition of the same total length, which can match a large-size imaging chip to achieve high-definition imaging.

[0064] In some embodiments, a focal length f3 of the third lens and an effective focal length f of the optical lens satisfy: 1.1<f3 / f<1.3. The third lens satisfying the above condition can balance the optical power, control the focus shift after high and low temperature, and avoid defocus.

[0065] In some embodiments, a focal length f5 of the fifth lens and an effective focal length f of the optical lens satisfy: 2<f5 / f<2.8. By satisfying the above condition, the focal length ratio of the fifth lens is reasonably set, which is conducive to the smooth transition of light, facilitates the correction of astigmatism and field curvature, improves the imaging quality of the optical lens, and ensures the stability of the optical system.

[0066] In some embodiments, a focal length f7 of the seventh lens and an effective focal length f of the optical lens satisfy: -5<f7 / f<-2.5. By satisfying the above condition, the seventh lens has a large negative optical power, which can make the incident light be divergent to a large extent, so that the peripheral light and the central light are turned up to a higher imaging position, better achieving large target surface imaging of the lens and improving the imaging quality.

[0067] In some embodiments, a back focal length BFL of the optical lens and an effective focal length f of the optical lens satisfy: 0.3<BFL / f<0.4. By satisfying the above condition, the lens has a suitable back focus, which ensures the compatibility of the lens and the body while making the structure of the lens more compact.

[0068] In some embodiments, the first lens has a radius of curvature R1 on the object side and a radius of curvature R2 on the image side, and R1 / R2 satisfies -13 < R1 / R2 < 22. Satisfying the above condition, the radii of curvature of the object side and the image side of the first lens are reasonably set, which helps to achieve a larger field of view.

[0069] In some embodiments, the third lens has a focal length f3 and the fourth lens has a focal length f4, and f3 / f4 satisfies 0.45 < f3 / f4 < 0.6. Satisfying the above condition, the optical power of the third lens and the fourth lens is reasonably distributed, which is conducive to the correction of chromatic aberration and improves the resolution of the system.

[0070] In some embodiments, the first lens has a focal length f1 and the seventh lens has a focal length f7, and f1 / f7 satisfies 0.4 < f1 / f7 < 0.8. Satisfying the above condition, by reasonably setting the focal length ratio of the first and last lenses, the lens can have a smaller head size while having a larger imaging surface, which can better meet the balance between miniaturization and high pixels.

[0071] In some embodiments, the optical lens has an effective focal length f, a maximum field of view FOV, and a real image height IH corresponding to the maximum field of view FOV, and 1.03 < (2 x f x tan(FOV / 2)) / IH < 1.04. Satisfying the above condition, the distortion of the optical lens is ≤4%, which can make the lens have a smaller distortion value and can provide a high-definition imaging effect.

[0072] In some embodiments, the optical lens has a maximum image height, and the chief ray angle of incidence CRA at the maximum image height satisfies 36° ≤ CRA < 37°. Satisfying the above condition, the CRA angle is increased, which can be adapted to a specific sensor (such as IMX586).

[0073] In some embodiments, the seventh lens has a radius of curvature R13 on the object side and a radius of curvature R14 on the image side, and (R13+R14) / (R13-R14) satisfies 1 < (R13+R14) / (R13-R14) < 3.8. Satisfying the above condition, the shape of the seventh lens can present M type, which is conducive to increasing the CRA and adapting to a specific sensor (such as IMX586).

[0074] In some embodiments, the first lens has a radius of curvature R2 on the image side and an effective focal length f of the optical lens, and R2 / f satisfies 1 < R2 / f < 1.3. Satisfying the above condition for the image side of the first lens can reduce the edge field of view light incidence angle, match the CRA tolerance of the CMOS sensor microlens, and avoid edge pixel signal attenuation.

[0075] In some embodiments, the object-side half-aperture radius DM11 of the first lens and the image-side half-aperture radius DM72 of the seventh lens satisfy: 1.4 < DM11 / DM72 < 1.6. By reasonably setting the ratio of the apertures of the first and last lenses, the lens can have a smaller head size while having a larger imaging surface, which can better balance miniaturization and high pixels.

[0076] In some embodiments, the object-side half-aperture sagittal height SAG71 of the seventh lens, the image-side half-aperture sagittal height SAG72 of the seventh lens, and the central thickness CT7 of the seventh lens satisfy: -0.1 < (SAG72-SAG71) / CT7 < 0.1. By controlling the ratio of the difference between the sagittal heights of the two surfaces of the seventh lens and the central thickness of the seventh lens, the machining and forming of the seventh lens can be facilitated, and the sensitivity of the seventh lens can be reduced, thereby better balancing the relationship between the miniaturization and the relative luminance of the off-axis field of view of the optical lens.

[0077] In some embodiments, the optical lens satisfies the condition: 3.9mm < f < 4mm, 15mm < TTL < 15.4mm, 2.1 < Fno < 2.3, 8.1mm < IH < 8.3mm, 94° < FOV < 95°, where f represents the effective focal length of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the real image height corresponding to the maximum field angle of the optical lens, and FOV represents the maximum field angle of the optical lens. Satisfying the above conditions indicates that the optical lens provided by the embodiments of the present application has the following characteristics: a smaller total optical length, which is conducive to better realizing the miniaturization and lightness of the device; a short focal length and a wide angle, the depth of field of the short focal length lens is relatively deep, and the subject can remain relatively clear in front and back; a larger field of view, which provides a wider shooting field of view for the lens of a drone and the like, and captures more image information; a larger imaging surface, which can match a larger size chip to realize high-definition imaging; and a larger aperture, which can realize high-definition imaging even in a complex light environment.

[0078] In some embodiments, the seven lenses in the optical lens can all be plastic lenses or adopt a glass-plastic hybrid material collocation structure. Preferably, the optical lens of the present application adopts a seven-lens glass-plastic hybrid collocation structure, which can improve the thermal stability. Specifically, the third lens can be a glass lens, and the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can all be plastic lenses. The glass-plastic hybrid structure can effectively reduce the cost, correct the aberration, reduce the size, and provide a higher cost-effective optical lens product.

[0079] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens can adopt a spherical lens or an aspherical lens. Compared with a spherical structure, an aspherical structure can effectively reduce aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving miniaturization of the optical lens. More specifically, the third lens in the optical lens provided by the application adopts a spherical lens, and the first lens, the second lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens all adopt an aspherical lens.

[0080] In various embodiments of the application, when the lens adopts an aspherical lens, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0081]

[0082] wherein z is the distance of the curved surface from the vertex of the curved surface in the direction of the optical axis, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the quadratic surface coefficient, and B, C, D, E, F, G and H are respectively the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order and sixteenth-order surface coefficients.

[0083] The application will be further described in the following embodiments. In various embodiments, the thickness, the radius of curvature and the material selection of each lens in the optical lens are different, and the specific differences can be referred to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the application, but the embodiments of the application are not limited to the following embodiments only, and any change, replacement, combination or simplification made without departing from the innovative points of the application should be regarded as equivalent replacement, and all are included in the protection scope of the application.

[0084] Embodiment 1

[0085] Please refer to Figure 1 , which is a structural schematic diagram of the optical lens 100 provided in the embodiment 1 of the application. The optical lens 100 includes, along the optical axis from the object side to the imaging surface S17, a first lens L1, a second lens L2, a third lens L3, a diaphragm ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and a filter G1.

[0086] The first lens L1 has a negative focal power, the object side surface S1 thereof is a convex surface, and the image side surface S2 thereof is a concave surface.

[0087] The second lens L2 has a negative focal power, the object side surface S3 thereof is a convex surface, and the image side surface S4 thereof is a concave surface.

[0088] The third lens L3 has a positive focal power, the object side surface S5 thereof is a convex surface, and the image side surface S6 thereof is a convex surface. ​

[0089] The fourth lens L4 has positive refractive power, the object side S7 is a convex surface, and the image side S8 is a convex surface;

[0090] The fifth lens L5 has positive refractive power, the object side S9 is a convex surface, and the image side S10 is a convex surface;

[0091] The sixth lens L6 has negative refractive power, the object side S11 is a concave surface, and the image side S12 is a concave surface;

[0092] The seventh lens L7 has negative refractive power, the object side S13 is a convex surface at the near optical axis, and the image side S14 is a concave surface at the near optical axis;

[0093] The object side S15 and the image side S16 of the filter G1 are both flat surfaces;

[0094] The imaging surface S17 is a flat surface.

[0095] The third lens L3 is a glass spherical lens; the first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all plastic aspherical lenses.

[0096] The related parameters of the lenses in the optical lens 100 in Embodiment 1 are shown in Table 1-1.

[0097] Table 1-1

[0098]

[0099] The surface type parameters of the aspherical lenses of the optical lens 100 in Embodiment 1 are shown in Table 1-2.

[0100] Table 1-2

[0101]

[0102] In this embodiment, the F-Tan(Theta) distortion curve, the axial chromatic aberration curve, the relative luminance curve, and the MTF curve of the optical lens 100 are shown in Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 respectively.

[0103] Figure 2 The F-Tan(Theta) distortion curve of the optical lens 100 in Embodiment 1 is shown, which represents the F-Tan(Theta) distortion of light rays at different image heights on the imaging surface. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Tan(Theta) distortion of the optical lens is controlled within -4%~2%, which shows that the optical lens 100 can correct distortion well.

[0104] Figure 3 A curve diagram of the sagittal chromatic aberration of the optical lens 100 in Embodiment 1 is shown, which represents the chromatic aberration of each wavelength at different image heights on the imaging plane relative to the central wavelength (0.587562 μm), the horizontal axis represents the sagittal chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. As can be seen from the diagram, the sagittal chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -0.5 μm~2 μm, which shows that the optical lens 100 can correct chromatic aberration well.

[0105] Figure 4 A relative illumination curve of the optical lens 100 in Embodiment 1 is shown, which represents the relative illumination value at different image heights on the imaging plane, the horizontal axis represents the half image height (unit: mm), and the vertical axis represents the relative illumination. As can be seen from the diagram, the relative illumination value of the optical lens at the maximum half image height is still greater than 0.4, which shows that the optical lens 100 has very good relative illumination.

[0106] Figure 5 A curve diagram of the MTF (Modulation Transfer Function) of the optical lens 100 in Embodiment 1 is shown, which represents the lens imaging modulation degree of different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the OTF coefficient. As can be seen from the diagram, the OTF coefficient of the present embodiment is above 0.4 within the full field of view, and in the range of 0~160 lp / mm, the curve uniformly and smoothly decreases from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in the case of low frequency and high frequency.

[0107] Embodiment 2

[0108] Please refer to Figure 6 , which is a structural schematic diagram of the optical lens 200 provided in Embodiment 2 of the present application. Compared with Embodiment 1, the main difference is that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.

[0109] The related parameters of each lens in the optical lens 200 in Embodiment 2 are shown in Table 2-1.

[0110] Table 2-1

[0111]

[0112] The surface type parameters of the aspherical lens of the optical lens 200 in Embodiment 2 are shown in Table 2-2.

[0113] Table 2-2

[0114]

[0115] In this embodiment, the F-Tan (Theta) distortion curve, transverse chromatic aberration curve, relative illumination curve, and MTF curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown.

[0116] from Figure 7 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within -4% to 2%, indicating that the optical lens 200 can correct distortion well.

[0117] from Figure 8 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -0.5μm to 2μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0118] from Figure 9 As can be seen, the relative illumination value of the optical lens at the maximum half-image height is still greater than 0.4, indicating that the optical lens 200 has good relative illumination.

[0119] from Figure 10 As can be seen, the OTF coefficient of this embodiment is above 0.4 throughout the entire field of view. In the range of 0 to 160 lp / mm, the curve decreases smoothly and evenly from the center to the edge of the field of view. It has good imaging quality and good detail resolution in both low and high frequency conditions.

[0120] Example 3

[0121] Please see Figure 11 The figure shows a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S1 of the first lens L1 is concave near the optical axis; the object side surface S9 of the fifth lens L5 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0122] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0123] Table 3-1

[0124]

[0125] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0126] Table 3-2

[0127]

[0128] In this embodiment, the F-Tan (Theta) distortion curve, transverse chromatic aberration curve, relative illumination curve, and MTF curve of the optical lens 300 are respectively as follows: Figure 12 , Figure 13 , Figure 14 , Figure 15 As shown.

[0129] from Figure 12 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within -4% to 2%, indicating that the optical lens 300 can correct distortion well.

[0130] from Figure 13 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -0.5μm to 2μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0131] from Figure 14 As can be seen, the relative illumination value of the optical lens at the maximum half-image height is still greater than 0.4, indicating that the optical lens 300 has very good relative illumination.

[0132] from Figure 15 As can be seen, the OTF coefficient of this embodiment is above 0.45 throughout the entire field of view. Within the range of 0 to 160 lp / mm, the curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and good detail resolution in both low and high frequency conditions.

[0133] Please refer to Table 4 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, true image height IH corresponding to the maximum field of view, principal ray incident angle CRA at the maximum image height, maximum field of view FOV, and the values ​​corresponding to each conditional expression in each embodiment.

[0134] Table 4

[0135]

[0136] In summary, the optical lens provided by this invention employs a seven-element glass-plastic hybrid structure. Through specific surface shape settings and reasonable power distribution, the optical lens structure is relatively compact, effectively shortening the overall length of the optical lens and facilitating miniaturization. It features a large aperture, enabling high-definition imaging even in low-light environments. Simultaneously, it has a large field of view, providing a wide viewing area. Furthermore, it can reasonably correct overall aberrations of the optical lens, exhibiting low distortion and high resolution, thus improving the imaging quality of the optical lens.

[0137] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0138] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An optical lens, in total seven pieces of lenses, characterized in that, In order from the object side to the imaging plane along the optical axis, successively comprise: a first lens with negative refractive power, the image side surface of which is a concave surface; a second lens with negative refractive power, the object side surface of which is a convex surface, and the image side surface of which is a concave surface; a third lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; a fourth lens with positive refractive power, the object side surface of which is a convex surface, and the image side surface of which is a convex surface; a fifth lens with positive refractive power, the image side surface of which is a convex surface; a sixth lens with negative refractive power, the object side surface of which is a concave surface, and the image side surface of which is a concave surface; a seventh lens with negative refractive power, the object side surface of which is a convex surface at the near optical axis, and the image side surface of which is a concave surface at the near optical axis; wherein the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 3.8 < TTL / f < 3.

9.

2. The optical lens of claim 1, wherein, The effective focal length f of the optical lens, the maximum field of view angle FOV of the optical lens, and the real image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 45° < (f*FOV) / IH < 46°.

3. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.1 < f1 / f < -2.

4. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 2 < f4 / f < 2.

5.

5. The optical lens of claim 1, wherein, The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2 < f6 / f < -1.

3.

6. The optical lens of claim 1, wherein, The object side surface curvature radius R13 of the seventh lens and the image side surface curvature radius R14 of the seventh lens satisfy: 1.6 < R13 / R14 < 28.

7. The optical lens of claim 1, wherein, The object side surface curvature radius R1 of the first lens and the image side surface curvature radius R2 of the first lens satisfy: 0.8 < (R1+R2) / (R1-R2) < 1.

25.

8. The optical lens of claim 1, wherein, The focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.5 < f5 / f6 < -1.

4.

9. The optical lens of claim 1, wherein, The sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis and the total optical length TTL of the optical lens satisfy: 0.55 < ∑CT / TTL < 0.

65.

10. The optical lens of claim 1, wherein, The real image height IH corresponding to the maximum field of view angle of the optical lens and the aperture value Fno of the optical lens satisfy: 3.7mm < IH / Fno < 3.8mm.

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