Optical lens
By employing an eight-lens structure and an aspherical design, the problems of size, weight, and image quality of fisheye lenses have been solved, resulting in improved wide field of view, high image quality, and light transmission performance.
Patent Information
- Application Number
- CN202311261128.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-27
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2043-09-27
AI Technical Summary
Existing fisheye lenses suffer from problems such as large size, heavy weight, increased field of view leading to difficulties in system aberration correction, decreased imaging quality, poor light transmission performance, and small target surface, which cannot meet market demands.
Design an eight-lens structure, including a combination of negative and positive power lenses, combined with a reflective element and a protective lens, to optimize the configuration of optical power and radius of curvature, meet specific focal length and field of view requirements, and use aspherical lenses to improve image quality.
It achieves an optical lens with a wide field of view, high imaging quality, large aperture, small size, and large target surface, which improves imaging effect and light transmission performance, and reduces aberration and chromatic aberration.
Smart Images
Figure CN117270171B_ABST
Abstract
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 continuous progress of existing image processing algorithms and AI technology, fisheye lenses, as a special type of optical lens, are widely used in action cameras, drones, smart doorbells, smart homes and other fields. Therefore, the requirements for fisheye lenses are becoming higher and higher.
[0003] However, the existing fisheye lens devices still have many shortcomings, such as the lens size is too long, the volume is large, the weight is heavy, which is not convenient for carrying; the field of view angle of the lens is increased, which leads to difficulty in system aberration correction and decline in imaging quality; the relative aperture of the lens is small, the light transmission performance is poor, and it cannot adapt to dark environment; and the existing lens imaging target surface is small, which is difficult to meet the market demand.
[0004] Therefore, it is necessary to develop an optical lens with one or more advantages of large field of view angle, high imaging quality, large aperture, small size, large target surface, etc., so as to better meet the high demand of the market for fisheye lenses. SUMMARY
[0005] In view of the above problems, the purpose of the present application is to provide an optical lens with the advantage of excellent imaging quality.
[0006] The present application provides an optical lens, which comprises eight lenses in sequence along the optical axis from the object side to the imaging surface:
[0007] The first lens with negative focal power has a convex object side and a concave image side;
[0008] The second lens with negative focal power has a concave image side;
[0009] The third lens with positive focal power has a convex object side and a convex image side;
[0010] The fourth lens with positive focal power has a convex object side and a convex image side;
[0011] The fifth lens with positive focal power has a convex object side and a convex image side;
[0012] The sixth lens with negative focal power has a concave object side and a concave image side;
[0013] The seventh lens with negative focal power has a convex object side and a concave image side;
[0014] The eighth lens with positive focal power has a convex object side and a concave image side;
[0015] The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: f7 / f<-5.0.
[0016] Further preferably, a reflective element is arranged between the third lens and the fourth lens, an incident surface of the reflective element is towards the object side, and an exit surface of the reflective element is towards the imaging surface.
[0017] Further preferably, the reflective element is a prism, and the incident surface and the exit surface of the prism are both planar.
[0018] Further preferably, a protective lens is arranged between the first lens and the object side, and a surface of the protective lens towards the object side is convex, and a surface of the protective lens towards the image side is concave.
[0019] Further preferably, the object side surface of the seventh lens has a radius of curvature R 13 and the image side surface has a radius of curvature R 14 satisfy: (R 13 +R 14 ) / (R 13 -R 14) >1.8.
[0020] Further preferably, the distance CT 34 between the third lens and the fourth lens on the optical axis satisfies: 4.0<CT 34 / f<5.5.
[0021] Further preferably, the maximum field of view FOV of the optical lens satisfies: FOV>190°.
[0022] Further preferably, the total track length TTL of the optical lens and the effective focal length f satisfy: 17.0<TTL / f<20.0.
[0023] Further preferably, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view satisfy: 3.0<IH / f<4.0.
[0024] Further preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -5.0<f1 / f<-3.0.
[0025] Further preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.0<f2 / f<-3.0.
[0026] The optical lens provided by the application improves the imaging quality of the optical lens, reduces aberration, and improves the imaging quality of the optical lens by reasonable configuration of the surface type of each lens and reasonable matching of the optical power. BRIEF DESCRIPTION OF DRAWINGS
[0027] 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:
[0028] Figure 1 and Figure 2 are respectively the structural schematic diagrams of the optical lens without protective lens and with protective lens in the embodiment 1 of the present application.
[0029] Figure 3 is the field curvature curve of the optical lens in the embodiment 1 of the present application.
[0030] Figure 4 is the F-Theta distortion curve of the optical lens in the embodiment 1 of the present application.
[0031] Figure 5 is the relative illumination curve of the optical lens in the embodiment 1 of the present application.
[0032] Figure 6 is the MTF curve of the optical lens in the embodiment 1 of the present application.
[0033] Figure 7 is the axial aberration curve of the optical lens in the embodiment 1 of the present application.
[0034] Figure 8 is the lateral chromatic aberration curve of the optical lens in the embodiment 1 of the present application.
[0035] Figure 9 and Figure 10 are respectively the structural schematic diagrams of the optical lens without protective lens and with protective lens in the embodiment 2 of the present application.
[0036] Figure 11 is the field curvature curve of the optical lens in the embodiment 2 of the present application.
[0037] Figure 12 is the F-Theta distortion curve of the optical lens in the embodiment 2 of the present application.
[0038] Figure 13 is the relative illumination curve of the optical lens in the embodiment 2 of the present application.
[0039] Figure 14 is the MTF curve of the optical lens in the embodiment 2 of the present application.
[0040] Figure 15 is the axial aberration curve of the optical lens in the embodiment 2 of the present application.
[0041] Figure 16 is the lateral chromatic aberration curve of the optical lens in the embodiment 2 of the present application.
[0042] Figure 17 and Figure 18 are respectively the structure diagram of the optical lens without protective lens and the optical lens with protective lens in the embodiment 3 of the present application.
[0043] Figure 19 is the field curvature curve of the optical lens in the embodiment 3 of the present application.
[0044] Figure 20 is the F-Theta distortion curve of the optical lens in the embodiment 3 of the present application.
[0045] Figure 21 is the relative illumination curve of the optical lens in the embodiment 3 of the present application.
[0046] Figure 22 is the MTF curve of the optical lens in the embodiment 3 of the present application.
[0047] Figure 23 is the axial aberration curve of the optical lens in the embodiment 3 of the present application.
[0048] Figure 24 is the lateral chromatic aberration curve of the optical lens in the embodiment 3 of the present application.
[0049] Figure 25 and Figure 26 are respectively the structure diagram of the optical lens without protective lens and the optical lens with protective lens in the embodiment 4 of the present application.
[0050] Figure 27 is the field curvature curve of the optical lens in the embodiment 4 of the present application.
[0051] Figure 28 is the F-Theta distortion curve of the optical lens in the embodiment 4 of the present application.
[0052] Figure 29 is the relative illumination curve of the optical lens in the embodiment 4 of the present application.
[0053] Figure 30 is the MTF curve of the optical lens in the embodiment 4 of the present application.
[0054] Figure 31 is the axial aberration curve of the optical lens in the embodiment 4 of the present application.
[0055] Figure 32 is the lateral chromatic aberration curve of the optical lens in the embodiment 4 of the present application.
[0056] The following detailed description will further illustrate the present application in combination with the above-mentioned drawings. DETAILED DESCRIPTION
[0057] For a better understanding of the present application, various aspects of the present application will be presented in more detail by referring to the attached drawings. It should be understood that these detailed descriptions are merely descriptive of the embodiments of the present application and are not intended in any way to limit the scope of the present application. Throughout the specification, like drawing reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.
[0058] It should be noted that the expressions first, second, third and the like in this specification are used only to distinguish one feature from another feature, and do not indicate any limitation of the features. Thus, the first lens discussed below can also be referred to as a second lens or a third lens without departing from the teachings of the present application.
[0059] 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.
[0060] 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.
[0061] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. Furthermore, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or an illustration.
[0062] 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 should 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.
[0063] 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.
[0064] The optical lens of the embodiment of the present application comprises, in sequence along the optical axis from the object side to the imaging surface, a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a filter.
[0065] In some embodiments, the first lens can have a negative focal power, which is conducive to reducing the inclination angle of the incident light, thereby effectively sharing the large field of view on the object side. The object side of the first lens is convex, and the image side is concave, which is conducive to collecting as much edge field of view light as possible into the rear optical lens to achieve large-angle light collection.
[0066] In some embodiments, the second lens can have a negative focal power, which is helpful for smooth transition of light, expansion of the field of view angle of the optical imaging lens, reduction of the difficulty of correcting distortion and chromatic aberration of the rear-end lens, and improvement of the image quality of the optical imaging lens. The image side of the second lens is concave, which is conducive to increasing the field of view angle of the optical lens and improving the imaging quality of the optical lens.
[0067] In some embodiments, the third lens can have a positive focal power, which is conducive to improving the light convergence ability of the optical lens. The object side and the image side of the third lens are both convex, which is conducive to balancing various aberrations generated by the optical lens and improving the imaging quality of the optical lens.
[0068] In some embodiments, the fourth lens can have a positive focal power, and its object side and image side are both convex, which is conducive to improving the light convergence ability of the optical lens while balancing the aberration of the optical lens and improving the imaging quality of the optical lens.
[0069] In some embodiments, the fifth lens can have a positive focal power, and its object side and image side are both convex, which is conducive to improving the light convergence ability of the optical lens while balancing the aberration of the optical lens and improving the imaging quality of the optical lens.
[0070] In some embodiments, the sixth lens can have a negative focal power, and its object side and image side are both concave, which is conducive to increasing the field of view angle of the optical lens and improving the imaging quality of the optical lens.
[0071] In some embodiments, the seventh lens can have a negative focal power, and its object side is convex and the image side is concave, which is conducive to increasing the field of view angle of the optical lens and improving the imaging quality of the optical lens.
[0072] In some embodiments, the eighth lens has positive refractive power, the object side surface is convex, and the image side surface is concave, which is beneficial to suppress the angle of the edge field of view incident on the imaging surface, effectively transfer more light beams to the imaging surface, balance aberration of the optical lens, and improve the imaging quality of the optical lens.
[0073] In some embodiments, in order to reduce the size of the optical lens, a reflection element with no refractive power for light path folding is arranged between the third lens and the fourth lens, and the reflection element is a prism. The surface of the prism towards the object side is an incident surface, and the surface of the prism towards the imaging surface is an exit surface. Both the incident surface and the exit surface are planes. The prism can be a right-angle prism. The light rays from the object side direction enter the prism from the incident surface, are reflected by the reflection surface, and then exit from the exit surface. The thickness of the optical lens can be effectively shortened by the arrangement of the prism.
[0074] In some embodiments, in order to protect the first lens which is in contact with the outside, a protective lens with refractive power is arranged between the first lens and the object side. The object side surface of the protective lens is convex, and the image side surface is concave. The protective lens can protect the optical lens, improve the impact resistance and scratch resistance of the optical lens, and has little effect on the imaging quality of the optical lens.
[0075] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: f7 / f<-5.0. The seventh lens has negative refractive power when the above range is satisfied, which is beneficial to increase the field of view angle of the optical lens and improve the imaging quality of the optical lens.
[0076] In some embodiments, the object side surface of the seventh lens has a curvature radius R 13 and the image side surface has a curvature radius R 14 satisfy: (R 13 +R 14 ) / (R 13 -R 14) >1.8. The above range is satisfied to control the edge field of view beam walking to increase the image height and reduce the off-axis aberration of the optical lens.
[0077] In some embodiments, the distance CT 34 between the third lens and the fourth lens on the optical axis and the effective focal length f of the optical lens satisfy: 4.0<CT 34 / f<5.5. The above range is satisfied to realize the folding structure of the optical lens and reduce the thickness of the optical lens.
[0078] In some embodiments, the maximum field of view angle FOV of the optical lens satisfies: FOV>190°. The above range is satisfied to realize the optical lens with a large field of view angle.
[0079] In some embodiments, the optical total track length TTL of the optical lens and the effective focal length f satisfy: 17.0 < TTL / f < 20.0. Satisfying the above range ensures sufficient space for adjusting the lens structure and optimizing the imaging effect.
[0080] In some embodiments, the effective focal length f of the optical lens, the radian of the maximum half field angle θ, and the real image height IH corresponding to the maximum field angle satisfy: 0.8 < (IH / 2) / (f x θ) < 1.1. Satisfying the above range controls the distortion within a suitable range and is conducive to increasing the real image height.
[0081] In some embodiments, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 3.0 < IH / f < 4.0. Satisfying the above range can achieve a large image surface characteristic and improve the imaging quality of the optical lens.
[0082] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -5.0 < f1 / f < -3.0. Satisfying the above range can make the first lens have a proper negative focal length, avoid excessive concentration of the negative focal length, and be conducive to increasing the field angle and collecting as much edge field light as possible into the rear optical lens to achieve large-angle light collection.
[0083] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.0 < f2 / f < -3.0. Satisfying the above range can make the second lens have a proper negative focal length, increase the field angle, and improve the imaging quality of the optical lens.
[0084] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 4.0 < f3 / f < 7.0. Satisfying the above range can make the third lens have a proper positive focal length, be conducive to improving the light convergence ability of the optical lens, and balance various aberrations generated by the optical lens to improve the imaging quality of the optical lens.
[0085] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 3.0 < f4 / f < 4.0. Satisfying the above range can make the fourth lens have a proper positive focal length, be conducive to improving the light convergence ability of the optical lens, and balance the aberration of the optical lens to improve the imaging quality of the optical lens.
[0086] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 2.0 < f5 / f < 3.0. Satisfying the above range can make the fifth lens have a proper positive focal length, be conducive to improving the light convergence ability of the optical lens, and balance the aberration of the optical lens to improve the imaging quality of the optical lens.
[0087] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2.5 < f6 / f < -1.5. Satisfying the above range, the sixth lens can have appropriate negative refractive power, which is conducive to increasing the field of view of the optical lens and improving the imaging quality of the optical lens.
[0088] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: 5.0 < f8 / f < 9.0. Satisfying the above range, the eighth lens can have appropriate positive refractive power, which is conducive to suppressing the angle of the edge field of view incident on the imaging surface, effectively transmitting more light beams to the imaging surface, balancing the aberration of the optical lens, and improving the imaging quality of the optical lens.
[0089] In some embodiments, the focal length f1 of the first lens of the optical lens and the focal length f2 of the second lens satisfy: 0.9 < f1 / f2 < 1.1. Satisfying the above range, the first lens and the second lens can have appropriate negative refractive power, which is conducive to smooth transition of light, expanding the field of view of the optical lens, reducing the difficulty of correcting distortion and chromatic aberration of the rear lens, and improving the imaging quality of the optical lens.
[0090] In some embodiments, the sixth lens and the seventh lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the sensitivity of the optical lens to decentration, balance the aberration of the optical lens, improve the imaging quality of the optical lens, reduce the assembly sensitivity of the optical lens, and further reduce the difficulty of the processing technology of the optical lens and improve the assembly yield of the optical lens.
[0091] In order to make the system have better optical performance, multiple aspheric lenses are used in the lens, and the shape of each aspheric surface of the optical lens satisfies the following equation:
[0092]
[0093] 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, A, B, C, D, E, F are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients, respectively.
[0094] The application will be further described in the following embodiments. In each embodiment, 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 changes, substitutions, combinations or simplifications made without departing from the innovative points of the application should be regarded as equivalent replacement methods, and are included in the protection scope of the application.
[0095] Embodiment 1
[0096] Referring to Figure 1 FIG. 1 shows a structural diagram of an optical lens provided in Embodiment 1 of the present application, which comprises, along the optical axis from the object side to the imaging surface, a first lens L1, a second lens L2, a third lens L3, a prism G1, a fourth lens L4, a stop ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G2.
[0097] The first lens L1 has negative focal power, and its object side surface S1 is convex and its image side surface S2 is concave;
[0098] The second lens L2 has negative focal power, and its object side surface S3 is convex and its image side surface S4 is concave;
[0099] The third lens L3 has positive focal power, and both its object side surface S5 and its image side surface S6 are convex;
[0100] The prism G1 has a plane as its object side surface and a plane as its image side surface;
[0101] The fourth lens L4 has positive focal power, and both its object side surface S7 and its image side surface S8 are convex;
[0102] The stop ST;
[0103] The fifth lens L5 has positive focal power, and both its object side surface S9 and its image side surface S10 are convex;
[0104] The sixth lens L6 has negative focal power, and both its object side surface S11 and its image side surface S12 are concave;
[0105] The seventh lens L7 has negative focal power, and its object side surface S12 is convex and its image side surface S13 is concave;
[0106] The sixth lens L6 and the seventh lens L7 form a cemented lens group, and the cemented surface S12 is formed by the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7;
[0107] The eighth lens L8 has positive focal power, and its object side surface S14 is convex and its image side surface S15 is concave;
[0108] The object side surface S16 and the image side surface S17 of the filter G2 are both plane;
[0109] The imaging surface S18 is plane.
[0110] The related parameters of the lenses in the optical lens in Embodiment 1 are shown in Table 1-1.
[0111] Table 1-1
[0112]
[0113] The surface parameters of the aspherical lens of the optical lens in Embodiment 1 are shown in Table 1-2.
[0114] Table 1-2
[0115]
[0116] Referring to Figure 2 In this embodiment, in order to protect the optical lens, a detachable protective lens with negative focal power can be added between the first lens L1 and the object side, and the object side surface S19 is convex and the image side surface S20 is concave. The relevant parameters are shown in Table 1-3.
[0117] Table 1-3
[0118]
[0119] In this embodiment, the field curvature curve, F-Theta distortion curve, relative illumination curve, MTF curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens are shown in Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 respectively.
[0120] Figure 3 The field curvature curve of Embodiment 1 is shown, which represents the curvature of light rays of different wavelengths on the meridional image surface and the sagittal image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image surface and the sagittal image surface is controlled within -0.03~0.01mm, which shows that the optical lens can well correct the field curvature.
[0121] Figure 4 The F-Theta distortion curve of Embodiment 1 is shown, which represents the F-Theta distortion of light rays of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Theta distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within -12%~0, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.
[0122] Figure 5The relative luminance curve of the embodiment 1 is shown, which represents the relative luminance values of different field angles on the imaging plane, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative luminance (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 good relative luminance.
[0123] Figure 6 The MTF (modulation transfer function) curve of the 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 MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.4 in the full field of view, and in the range of 0-160 lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge field of view, and has good imaging quality and good detail resolution capability in the case of low frequency and high frequency.
[0124] Figure 7 The axial aberration curve of the embodiment 1 is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within-10 μm~10 μm, which indicates that the optical lens can better correct the axial aberration.
[0125] Figure 8 The axial aberration curve of the embodiment 1 is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within-10 μm~10 μm, which indicates that the optical lens can better correct the axial aberration.
[0126] Embodiment 2
[0127] Please refer to Figure 9 , which is a structural schematic diagram of the optical lens provided in the embodiment 2 of the present application, and compared with the embodiment 1, the main difference is that the curvature radius, lens thickness and other optical parameters of each lens surface are different.
[0128] The related parameters of each lens in the optical lens in the embodiment 2 are shown in Table 2-1.
[0129] Table 2-1
[0130]
[0131] The surface type parameters of the aspheric lens of the optical lens in the embodiment 2 are shown in Table 2-2.
[0132] Table 2-2
[0133]
[0134] Referring to Figure 10 In this embodiment, in order to protect the optical lens, a detachable protective lens can be added between the first lens L1 and the object side, and the protective lens has a negative focal power, the object side S19 is a convex surface, and the image side S20 is a concave surface. The related parameters are shown in Table 2-3.
[0135] Table 2-3
[0136]
[0137] In this embodiment, the field curvature curve, F-Theta distortion curve, relative illumination curve, MTF curve, axial aberration curve, and transverse chromatic aberration curve of the optical lens are shown in Figure 11 、 Figure 12 、 Figure 13 、 Figure 14 、 Figure 15 、 Figure 16 .
[0138] Figure 11 The field curvature curve of Example 2 is shown, which represents the curvature of light rays of different wavelengths on the meridional image surface and the sagittal image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image surface and the sagittal image surface is controlled within -0.02~0.01mm, which shows that the optical lens can well correct the field curvature.
[0139] Figure 12 The F-Theta distortion curve of Example 2 is shown, which represents the F-Theta distortion of light rays of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Theta distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within 0~6%, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.
[0140] Figure 13 The relative illumination curve of Example 2 is shown, which represents the relative illumination value of different field angles on the imaging surface, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 40% at the maximum half field angle, which shows that the optical lens has good relative illumination.
[0141] Figure 14The MTF (Modulation Transfer Function) curve of the embodiment 2 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 MTF value. It can be seen from the figure that the MTF value of the embodiment is above 0.4 in the full field of view, and in the range of 0-160 lp / mm, the MTF curve uniformly and smoothly decreases from the center to the edge field of view, and has good imaging quality and good detail resolution capability in the case of low frequency and high frequency.
[0142] Figure 15 The axial aberration curve of the embodiment 2 is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the shift amount of the axial aberration is controlled within-10 μm~15 μm, which indicates that the optical lens can better correct the axial aberration.
[0143] Figure 16 The curve of the embodiment 2 is shown, which represents the axial aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the shift amount of the axial aberration is controlled within-10 μm~15 μm, which indicates that the optical lens can better correct the axial aberration.
[0144] Embodiment 3
[0145] Please refer to Figure 17 , which is a structural schematic diagram of the optical lens provided in the embodiment 3 of the present application, which comprises, along the optical axis from the object side to the imaging surface, a first lens L1, a second lens L2, a third lens L3, a prism G1, a fourth lens L4, a diaphragm ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G2.
[0146] The first lens L1 has a negative focal power, the object side S1 is a convex surface, and the image side S2 is a concave surface;
[0147] The second lens L2 has a negative focal power, and the object side S3 and the image side S4 are both concave surfaces;
[0148] The third lens L3 has a positive focal power, and the object side S5 and the image side S6 are both convex surfaces;
[0149] The prism G1 has an incident surface towards the object side and an exit surface towards the imaging surface, and both the incident surface and the exit surface are flat surfaces;
[0150] The fourth lens L4 has positive refractive power, and both the object side S7 and the image side S8 are convex surfaces;
[0151] The stop ST;
[0152] The fifth lens L5 has positive refractive power, and both the object side S9 and the image side S10 are convex surfaces;
[0153] The sixth lens L6 has negative refractive power, and both the object side S11 and the image side S12 are concave surfaces;
[0154] The seventh lens L7 has negative refractive power, and the object side S12 is a convex surface and the image side S13 is a concave surface;
[0155] The sixth lens L6 and the seventh lens L7 form a cemented lens group, and the cemented surface S12 is formed by the image side of the sixth lens L6 and the object side of the seventh lens L7;
[0156] The eighth lens L8 has positive refractive power, and the object side S14 is a convex surface and the image side S15 is a concave surface;
[0157] Both the object side S16 and the image side S17 of the filter G2 are flat surfaces;
[0158] The imaging surface S18 is a flat surface.
[0159] The related parameters of the lenses in the optical lens in Embodiment 3 are shown in Table 3-1.
[0160] Table 3-1
[0161]
[0162] The surface type parameters of the aspherical lenses in the optical lens in Embodiment 3 are shown in Table 3-2.
[0163] Table 3-2
[0164]
[0165] Reference is made to Figure 18 In this embodiment, in order to protect the optical lens, a detachable protective lens can be added between the first lens L1 and the object side. The protective lens has positive refractive power, the object side S19 is a convex surface, and the image side S20 is a concave surface. The related parameters are shown in Table 3-3.
[0166] Table 3-3
[0167]
[0168] In this embodiment, the field curvature curve, the F-Theta distortion curve, the relative luminance curve, the MTF curve, the axial aberration curve, and the transverse chromatic aberration curve of the optical lens are respectively as shown inFigure 19 、 Figure 20 、 Figure 21 、 Figure 22 、 Figure 23 、 Figure 24 as shown in FIG. 6.
[0169] Figure 19 FIG. 7 shows the field curvature curve of the optical lens of embodiment 3, which represents the curvature of light rays of different wavelengths on the sagittal image plane and the tangential image plane, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the field curvature of the sagittal image plane and the tangential image plane is controlled within -0.05~0.02mm, which shows that the optical lens can well correct the field curvature.
[0170] Figure 20 FIG. 8 shows the F-Theta distortion curve of the optical lens of embodiment 3, which represents the F-Theta distortion of light rays of different wavelengths at different image heights on the imaging plane, the horizontal axis represents the F-Theta distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within 0~8%, the image compression in the edge angle region is relatively flat, and the clarity of the expanded image is effectively improved.
[0171] Figure 21 FIG. 9 shows the relative illumination curve of the optical lens of embodiment 3, which represents the relative illumination value of different field angles on the imaging plane, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 40% at the maximum half field angle, which shows that the optical lens has good relative illumination.
[0172] Figure 22 FIG. 10 shows the MTF (Modulation Transfer Function) curve of the optical lens of embodiment 3, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.3 within the full field of view, and within the range of 0~160lp / mm, the MTF 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 both low frequency and high frequency cases.
[0173] Figure 23 FIG. 11 shows the axial aberration curve of the optical lens of embodiment 3, which represents the aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within -20μm~15μm, which shows that the optical lens can well correct the axial aberration.
[0174] Figure 24The vertical axis represents the relative vertical color aberration value (unit: μm) of each wavelength to the central wavelength (0.55 μm), and the horizontal axis represents the normalized field angle. It can be seen from the figure that the vertical color aberration of the longest wavelength and the shortest wavelength is controlled within -3 μm~1 μm, which indicates that the optical lens can well correct the color aberration of the edge field of view and the secondary spectrum of the whole image plane.
[0175] Embodiment 4
[0176] Please refer to Figure 25 , which is a structural schematic diagram of the optical lens provided in Embodiment 4 of the present application. Compared with Embodiment 3, the main difference of the present embodiment is that the optical parameters such as the radius of curvature of each lens surface and the lens thickness are different.
[0177] The related parameters of each lens in the optical lens in Embodiment 4 are shown in Table 4-1.
[0178] Table 4-1
[0179]
[0180] The surface type parameters of the aspheric lens of the optical lens in Embodiment 4 are shown in Table 4-2.
[0181] Table 4-2
[0182]
[0183] Please refer to Figure 26 , in the present embodiment, in order to protect the optical lens, a detachable protective lens can be added between the first lens L1 and the object side, which has positive focal power, and the object side surface S19 is a convex surface and the image side surface S20 is a concave surface. The related parameters are shown in Table 4-3.
[0184] Table 4-3
[0185]
[0186] In the present embodiment, the field curvature curve, the F-Theta distortion curve, the relative luminance curve, the MTF curve, the axial aberration curve and the vertical color aberration curve of the optical lens are shown in Figure 27 、 Figure 28 、 Figure 29 、 Figure 30 、 Figure 31 、 Figure 32 respectively.
[0187] Figure 27The field curvature curve of embodiment 4 is shown, which represents the bending degree of light rays of different wavelengths on the meridional image surface and the sagittal image surface, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the field curvature of the meridional image surface and the sagittal image surface is controlled within-0.05~0.02mm, which shows that the optical lens can well correct the field curvature.
[0188] Figure 28 The F-Theta distortion curve of embodiment 4 is shown, which represents the F-Theta distortion of light rays of different wavelengths at different image heights on the imaging surface, the horizontal axis represents the F-Theta distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). As can be seen from the figure, the F-Theta distortion of the optical lens is controlled within 0~3%, the image compression in the edge angle region is relatively flat, and the clarity of the unfolded image is effectively improved.
[0189] Figure 29 The relative luminance curve of embodiment 4 is shown, which represents the relative luminance value of different field angles on the imaging surface, the horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative luminance (unit: %). As can be seen from the figure, the relative luminance value of the optical lens is still greater than 40% at the maximum half field angle, which shows that the optical lens has good relative luminance.
[0190] Figure 30 The MTF (Modulation Transfer Function) curve of embodiment 4 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of the embodiment is above 0.4 in the full field of view, and in the range of 0~160lp / mm, the MTF 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 low and high frequency conditions.
[0191] Figure 31 The axial aberration curve of embodiment 4 is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within-20μm~10μm, which shows that the optical lens can well correct the axial aberration.
[0192] Figure 32The vertical color aberration curve of embodiment 4 is shown, which represents the color aberration of each wavelength at different image heights on the imaging plane relative to the central wavelength (0.55 μm), the horizontal axis represents the vertical color 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 figure, the vertical color aberration of the longest wavelength and the shortest wavelength is controlled within -2 μm ~ 1 μm, which indicates that the optical lens can very well correct the color aberration of the edge field of view and the secondary spectrum of the entire image plane.
[0193] Referring to Table 5, the optical characteristics of the above-mentioned embodiments are shown, including the effective focal length f, the total optical length TTL, the aperture value FNO, the real image height IH, and the maximum field angle FOV of the optical lens, and the numerical values corresponding to each conditional expression in the embodiments.
[0194] Table 5
[0195]
[0196] In summary of the above embodiments, the optical lens provided by the present application improves the imaging quality of the optical lens, reduces the aberration, and improves the imaging quality of the optical lens by reasonable configuration of each lens surface and reasonable matching of the optical power.
[0197] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "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 description of the above terms does not necessarily mean 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.
[0198] The above-described embodiments only express several embodiments of the present application, which are described in a more specific and detailed manner, but should not be understood as limiting the scope of the patent of the present application. It should be noted that for ordinary skilled 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, eight pieces of lenses in total, characterized in that, In order from the object side to the imaging surface along the optical axis, there are sequentially arranged: a first lens with negative refractive power, whose object side surface is convex and whose image side surface is concave; a second lens with negative refractive power, whose image side surface is concave; a third lens with positive refractive power, whose object side surface and image side surface are both convex; a fourth lens with positive refractive power, whose object side surface and image side surface are both convex; a fifth lens with positive refractive power, whose object side surface and image side surface are both convex; a sixth lens with negative refractive power, whose object side surface and image side surface are both concave; a seventh lens with negative refractive power, whose object side surface is convex and whose image side surface is concave; an eighth lens with positive refractive power, whose object side surface is convex and whose image side surface is concave; a focal length f7 of the seventh lens and an effective focal length f of the optical lens satisfy: f7 / f <-5.0; an effective focal length f of the optical lens and a real image height IH corresponding to a maximum field of view angle satisfy: 3.0<IH / f<4.
0.
2. The optical lens of claim 1, wherein, A reflective element is arranged between the third lens and the fourth lens, a surface of the reflective element facing the object side is an incident surface, and a surface of the reflective element facing the imaging surface is an exit surface.
3. The optical lens of claim 1, wherein, A protective lens is arranged between the first lens and the object side, an object side surface of the protective lens is convex, and an image side surface of the protective lens is concave.
4. The optical lens of claim 1, wherein, A radius of curvature R13 of the object side surface of the seventh lens and a radius of curvature R14 of the image side surface of the seventh lens satisfy: (R13+R14) / (R13-R14) >1.
8.
5. The optical lens of claim 1, wherein, A distance CT34 on the optical axis between the third lens and the fourth lens and an effective focal length f of the optical lens satisfy: 4.0<CT34 / f<5.
5.
6. The optical lens of claim 1, wherein, A maximum field of view angle FOV of the optical lens satisfies: FOV>190°.
7. The optical lens of claim 1, wherein, An optical total length TTL of the optical lens and an effective focal length f satisfy: 17.0<TTL / f<20.
0.
8. The optical lens of claim 1, wherein, The optical lens satisfies one or more of the following conditional expressions: A focal length f7 of the seventh lens and an effective focal length f of the optical lens satisfy: -5.20E+07≤f7 / f≤-5.24; An effective focal length f of the optical lens and a real image height IH corresponding to a maximum field of view angle satisfy: 3.11≤IH / f≤3.68; A radius of curvature R13 of the object side surface of the seventh lens and a radius of curvature R14 of the image side surface of the seventh lens satisfy: 66.35 ≥(R13+R14) / (R13-R14) >1.8; A maximum field of view angle FOV of the optical lens satisfies: 210°≥FOV>190°.
9. The optical lens of claim 1, wherein, A focal length f1 of the first lens and an effective focal length f of the optical lens satisfy: -5.0<f1 / f<-3.
0.
10. The optical lens of claim 1, wherein, A focal length f2 of the second lens and an effective focal length f of the optical lens satisfy: -5.0<f2 / f<-3.0.
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CN101135770A