Optical lens

Abstract

The invention provides an optical lens, which comprises eight lenses from an object side to an imaging surface along an optical axis: a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power, the image side surface of the second lens is a concave surface; the object side surface and the image side surface of the third lens are convex surfaces; the object side surface and the image side surface of the fourth lens are convex surfaces; the fifth lens has positive focal power, and the object side surface of the fifth lens is a convex surface; the sixth lens has negative focal power, and the object side surface and the image side surface of the sixth lens are concave surfaces; the object side surface of the seventh lens is a convex surface; and the image side surface of the eighth lens is a concave surface. According to the optical lens provided by the invention, through reasonable configuration of the surface types of the lenses and reasonable matching of the focal power, the imaging quality of the optical lens is improved, the aberration is reduced, and the imaging quality of the optical lens is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and in particular to an optical lens. Background Art

[0002] With the continuous advancement of existing image processing algorithms and AI technologies, fisheye lenses, as a special type of optical lens, are widely used in various fields such as sports cameras, drones, smart doorbells and smart homes. Therefore, the requirements for fisheye lenses are getting higher and higher.

[0003] However, existing fisheye lens devices still have many shortcomings. For example, the lens is too long, large in size, and heavy in weight, which is not convenient to carry; the increased field of view of the lens makes it difficult to correct system aberrations and reduces the imaging quality; the relative aperture of the lens is small, the light transmission performance is poor, and it cannot adapt to darker environments; and the existing lens imaging target surface is small, which makes it difficult to meet market demand.

[0004] Therefore, it is necessary to develop an optical lens with one or more advantages such as a large field of view, high imaging quality, a large aperture, a small size, and a large target surface, so as to better meet the high market demand for fisheye lenses. Summary of the invention

[0005] In view of the above problems, an object of the present invention is to provide an optical lens having the advantage of excellent imaging quality.

[0006] The present invention provides an optical lens, which comprises eight lenses in total, and which includes the following lenses in order from the object side to the imaging surface along the optical axis:

[0007] The first lens has a negative optical power, and its object side surface is convex and its image side surface is concave;

[0008] A second lens having negative optical power, whose image side surface is concave;

[0009] The third lens has positive refractive power, and both the object side surface and the image side surface are convex;

[0010] The fourth lens has positive refractive power, and both the object side surface and the image side surface are convex;

[0011] a fifth lens having positive refractive power and a convex object side surface;

[0012] The sixth lens has negative optical power, and both the object side surface and the image side surface are concave;

[0013] a seventh lens having optical power and having a convex object side surface;

[0014] an eighth lens having optical power and having an image side surface which is concave;

[0015] The maximum field of view FOV of the optical lens satisfies: FOV>190°;

[0016] The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.8 <f1 / f2<1.6。

[0017] Further preferably, a reflective element is provided between the third lens and the fourth lens, and the surface of the reflective element facing the object side is an incident surface, and the surface facing the imaging surface is an exit surface.

[0018] Further preferably, the reflective element is a prism, and both the incident surface and the exit surface of the prism are planes.

[0019] Further preferably, the object side sag height Sag3 of the second lens and the object side semi-aperture d3 satisfy: -0.2 <Sag3 / d3<0。

[0020] Further preferably, the distance CT between the third lens and the fourth lens on the optical axis is 34 The effective focal length f of the optical lens satisfies: 5.0 <CT 34 / f<7.5.

[0021] Further preferably, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -1.0 <f2 / f3<-0.5。

[0022] Further preferably, 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。

[0023] Further preferably, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 5.0 <TTL / IH<7.0。

[0024] Further preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -6.0 <f1 / f<-4.0。

[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<-3.5。

[0026] The optical lens provided by the present invention improves the imaging quality of the optical lens, reduces aberrations, and improves the imaging quality of the optical lens through reasonable configuration of the surface shapes of each lens and reasonable matching of the optical focal length. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0028] Figure 1 and Figure 2 They are schematic diagrams of the structures of the optical lens without a protective lens and with a protective lens in Example 1 of the present invention.

[0029] Figure 3 It is a field curvature curve diagram of the optical lens in Example 1 of the present invention.

[0030] Figure 4 : is the F-Theta distortion curve of the optical lens in Example 1 of the present invention.

[0031] Figure 5 This is a relative illumination curve diagram of the optical lens in Example 1 of the present invention.

[0032] Figure 6 This is the MTF curve diagram of the optical lens in Example 1 of the present invention.

[0033] Figure 7 Graph showing the axial aberration of the optical lens in Example 1 of the present invention.

[0034] Figure 8 Graph showing the vertical axis chromatic aberration of the optical lens in Example 1 of the present invention.

[0035] Fig. 9 and Fig.10 They are schematic diagrams of the structures of the optical lens without a protective lens and with a protective lens in Example 2 of the present invention.

[0036] Fig.11 4 is a field curvature curve diagram of the optical lens in Example 2 of the present invention.

[0037] Fig.12 : is the F-Theta distortion curve of the optical lens in Example 2 of the present invention.

[0038] Fig.13 This is a relative illumination curve diagram of the optical lens in Example 2 of the present invention.

[0039] Fig.14 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0040] Fig.15 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0041] Fig.16 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0042] Fig.17 and Fig.18 They are schematic diagrams of the structures of the optical lens without a protective lens and with a protective lens in Example 3 of the present invention.

[0043] Fig.19 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0044] Fig. 20 : is the F-Theta distortion curve of the optical lens in Example 3 of the present invention.

[0045] Fig.21 This is a relative illumination curve diagram of the optical lens in Example 3 of the present invention.

[0046] Fig. 22 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0047] Fig.23 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0048] Fig.24 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0049] Fig.25 and Fig.26 They are schematic diagrams of the structures of the optical lens without a protective lens and with a protective lens in Example 4 of the present invention.

[0050] Fig. 27 It is a field curvature curve diagram of the optical lens in Example 4 of the present invention.

[0051] Fig.28 : is the F-Theta distortion curve of the optical lens in Example 4 of the present invention.

[0052] Fig.29 This is a relative illumination curve diagram of the optical lens in Example 4 of the present invention.

[0053] Fig.30 This is the MTF curve diagram of the optical lens in Example 4 of the present invention.

[0054] Fig.31 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0055] Fig.32 Graph showing the vertical axis chromatic aberration of the optical lens in Example 4 of the present invention.

[0056] Fig.33 and Fig.34 They are schematic diagrams of the structures of the optical lens without a protective lens and with a protective lens in Example 5 of the present invention.

[0057] Fig.35 4 is a field curvature curve diagram of the optical lens in Example 5 of the present invention.

[0058] Fig.36: is the F-Theta distortion curve of the optical lens in Example 5 of the present invention.

[0059] Fig.37 This is a relative illumination curve diagram of the optical lens in Example 5 of the present invention.

[0060] Fig.38 This is the MTF curve diagram of the optical lens in Example 5 of the present invention.

[0061] Fig.39 Graph showing the axial aberration of the optical lens in Embodiment 5 of the present invention.

[0062] Fig.40 Graph showing the vertical axis chromatic aberration of the optical lens in Example 5 of the present invention.

[0063] Fig.41 and Fig.42 They are schematic diagrams of the structures of the optical lens without a protective lens and with a protective lens in Example 6 of the present invention.

[0064] Fig.43 4 is a field curvature curve diagram of the optical lens in Example 6 of the present invention.

[0065] Fig.44 : is the F-Theta distortion curve of the optical lens in Example 6 of the present invention.

[0066] Fig.45 This is a relative illumination curve diagram of the optical lens in Example 6 of the present invention.

[0067] Fig.46 This is the MTF curve diagram of the optical lens in Example 6 of the present invention.

[0068] Fig.47 Graph showing the axial aberration of the optical lens in Embodiment 6 of the present invention.

[0069] Fig.48 Graph showing the vertical axis chromatic aberration of the optical lens in Example 6 of the present invention.

[0070] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0071] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0072] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0073] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0074] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0075] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0076] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0077] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0078] The optical lens of the embodiment of the present invention includes, in order from the object side to the imaging surface along the optical axis: a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a filter.

[0079] In some embodiments, the first lens may have a negative optical power, which is beneficial to reduce 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 beneficial to collect the edge field of view light as much as possible into the rear optical lens, and realize large-angle light collection.

[0080] In some embodiments, the second lens may have a negative optical power, which helps to smoothly transition the light, expand the field of view of the optical imaging lens, reduce the difficulty of the rear lens to correct distortion and chromatic aberration, and improve 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 of the optical lens and improving the imaging quality of the optical lens.

[0081] In some embodiments, the third lens may have positive focal length, which is beneficial to improving the light convergence capability of the optical lens. The object side and image side of the third lens are both convex, which is beneficial to balancing various aberrations generated by the optical lens and improving the imaging quality of the optical lens.

[0082] In some embodiments, the fourth lens may have positive optical power, and its object side surface and image side surface are both convex, which is beneficial to improving the light convergence ability of the optical lens, while being able to balance the aberration of the optical lens and improve the imaging quality of the optical lens.

[0083] In some embodiments, the fifth lens may have positive optical power, and its object side surface is convex, which is beneficial 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.

[0084] In some embodiments, the sixth lens may have negative optical power, and its object side surface and image side surface are both concave, which is beneficial to increasing the field of view of the optical lens and improving the imaging quality of the optical lens.

[0085] In some embodiments, the seventh lens element may have optical power, and its object-side surface is convex. The eighth lens element may have optical power, and its image-side surface is concave.

[0086] In some embodiments, in order to reduce the size of the optical lens, a reflective element with no optical power for folding the light path may be provided between the third lens and the fourth lens, and the reflective element is a prism. The surface of the prism facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface, and both the incident surface and the exit surface are planes. The prism may be a right-angle prism, and the light from the object side enters the prism from the incident surface, is reflected by the reflective surface, and then is emitted from the exit surface. By bending the light path through the prism, the thickness of the lens can be effectively shortened.

[0087] In some embodiments, in order to protect the first lens in contact with the outside, a protective lens with a focal power is provided 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. By providing the protective lens, it plays a role in protecting the optical lens, can improve the anti-impact and scratch-resistant capabilities of the optical lens, and has almost no impact on the imaging quality of the optical lens.

[0088] In some embodiments, the maximum field of view angle FOV of the optical lens satisfies: FOV > 190°. Meeting the above range can enable the optical lens to have a large field of view angle.

[0089] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.8 < f1 / f2 < 1.6. Meeting the above range can make the second lens have a smaller focal length, reduce the pressure of the first lens on the light deflection as much as possible, and improve the imaging quality of the optical lens.

[0090] In some embodiments, the sagittal height Sag3 of the object side surface of the second lens and the clear aperture radius d3 of the object side surface satisfy: -0.2 < Sag3 / d3 < 0. Meeting the above range is beneficial to capturing the edge field light and increasing the image height.

[0091] In some embodiments, the distance CT on the optical axis between the third lens and the fourth lens 34 and the effective focal length f of the optical lens satisfy: 5.0 < CT 34 / f < 7.5. Meeting the above range is beneficial to realizing the catadioptric structure of the optical lens and reducing the thickness of the lens.

[0092] In some embodiments, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -1.0 < f2 / f3 < -0.5. Meeting the above range can balance the aberration at the front end of the optical lens and improve the imaging quality of the optical lens.

[0093] In some embodiments, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 3.0 < IH / f < 4.0. Meeting the above range can achieve the large image plane characteristic and improve the imaging quality of the optical lens.

[0094] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 5.0 < TTL / IH < 7.0. Meeting the above range can effectively balance the requirements of the image height and size of the optical lens.

[0095] In some embodiments, the effective focal length f of the optical lens, the radian θ of the maximum half field of view angle, and the true image height IH corresponding to the maximum field of view angle satisfy: 0.9 < (IH / 2) / (f×θ) < 1.2. Meeting the above range, the distortion is controlled within a suitable range, which is beneficial to increasing the true image height.

[0096] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -6.0 < f1 / f < -4.0. Meeting the above range can make the first lens have an appropriate negative optical power, avoid over-concentration of the negative optical power, and at the same time is beneficial to increasing the field of view angle, facilitating the collection of marginal field light into the rear optical lens as much as possible, and realizing large-angle light collection.

[0097] 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 < -3.5. Meeting the above range can make the second lens have an appropriate negative optical power, increase the field of view angle, and improve the imaging quality of the optical lens.

[0098] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 5.0 < f3 / f < 7.5. Meeting the above range can make the third lens have an appropriate positive optical power, which is beneficial to improving the light converging ability of the optical lens, and at the same time can balance various aberrations generated by the optical lens, and improve the imaging quality of the optical lens.

[0099] 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. Meeting the above range can make the fourth lens have an appropriate positive optical power, which is beneficial to improving the light converging ability of the optical lens, and at the same time can balance the aberrations of the optical lens and improve the imaging quality of the optical lens.

[0100] 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 < 9.5. Meeting the above range can make the fifth lens have an appropriate positive optical power, which is beneficial to improving the light converging ability of the optical lens, and at the same time can balance the aberrations of the optical lens and improve the imaging quality of the optical lens.

[0101] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -12.0 < f6 / f < -1.5. Meeting the above range can make the sixth lens have an appropriate negative optical power, increase the field of view angle, and improve the imaging quality of the optical lens.

[0102] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: f7 / f < 2.5. Meeting the above range is beneficial to reducing the light deflection angle, making the light trend transition smoothly, and improving the imaging quality of the optical lens.

[0103] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -39.5 < f8 / f < 10.5. Satisfying the above range can make the eighth lens have an appropriate optical power, enabling the light rays to transition smoothly, and improving the imaging quality of the optical lens.

[0104] In some embodiments, the fifth lens and the sixth lens can be glued together to form a cemented lens, or the sixth lens and the seventh lens can be glued together to form a cemented lens, or the seventh lens and the eighth lens can be glued together to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0105] To enable the system to have better optical performance, multiple aspherical lenses are used in the lens, and the aspherical surface shapes of the optical lens satisfy the following equation:

[0106]

[0107] where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, 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 conic coefficient, and A, B, C, D, E, F are the surface coefficients of the second, fourth, sixth, eighth, tenth, and twelfth orders, respectively.

[0108] The protective lens adopts an aspherical surface type, and the aspherical surface shape satisfies the following equation:

[0109]

[0110] where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, 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 conic coefficient, and A, B, C, D, E, F, G, H are the surface coefficients of the second, fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders, respectively.

[0111] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are partially different. For specific differences, please refer to the parameter tables of each embodiment. The following embodiments are only the preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0112] Embodiment 1

[0113] See also Figure 1 , which is a schematic diagram of the structure of the optical lens provided in Embodiment 1 of the present invention, wherein the optical lens includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a prism G1, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G2.

[0114] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0115] The second lens L2 has negative refractive power, its object side surface S3 is convex, and its image side surface S4 is concave;

[0116] The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex;

[0117] The surface of the prism G1 facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface, and both the incident surface and the exit surface are planes;

[0118] The fourth lens L4 has positive refractive power, and its object-side surface S7 and image-side surface S8 are both convex surfaces;

[0119] Aperture ST;

[0120] The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave;

[0121] The sixth lens L6 has negative refractive power, and its object-side surface S11 and image-side surface S12 are both concave surfaces;

[0122] The seventh lens L7 has positive refractive power, and its object-side surface S12 and image-side surface S13 are both convex surfaces;

[0123] The sixth lens L6 and the seventh lens L7 form a cemented lens group, that is, the cemented surface between the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is S12;

[0124] The eighth lens L8 has negative optical power, its object side surface S14 is convex, and its image side surface S15 is concave; the object side surface S16 and the image side surface S17 of the filter G2 are both flat;

[0125] The imaging surface S18 is a plane.

[0126] The relevant parameters of each lens in the optical lens in Example 1 are shown in Table 1-1.

[0127] Table 1-1

[0128]

[0129] The surface parameters of the aspherical lens of the optical lens in Example 1 are shown in Table 1-2.

[0130] Table 1-2

[0131]

[0132]

[0133] See also Figure 2 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 focal length, and its object side surface S19 is convex, and its image side surface S20 is concave. Relevant parameters are shown in Table 1-3.

[0134] Table 1-3

[0135]

[0136] Among them, the surface parameters of the aspheric surface of the protective lens are shown in Table 1-4.

[0137] Table 1-4

[0138] Face number K A B C D E F G H S19 0.00E+00 0.00E+00 -1.17E-05 6.17E-09 2.32E-11 -1.58E-13 -1.64E-16 5.07E-19 -4.04E-23 S20 0.00E+00 0.00E+00 -8.89E-06 1.35E-08 -1.38E-10 3.31E-13 -6.18E-16 -2.13E-19 1.58E-21

[0139] In this embodiment, the field curvature curve, F-Theta distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 shown.

[0140] Figure 3 The field curvature curve of Example 1 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, with the horizontal axis indicating the offset (unit: mm) and the vertical axis indicating the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.02mm to 0.1mm, indicating that the optical lens can correct the field curvature well.

[0141] Figure 4 The F-Theta distortion curve of Example 1 is shown, which represents the F-Theta distortion of light 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: °). It can be seen from the figure that the F-Theta distortion of the optical lens is controlled within 0-10%, the image compression in the edge angle area is relatively gentle, and the clarity of the expanded image is effectively improved.

[0142] Figure 5 The relative illumination curve of Example 1 is shown, which represents the relative illumination values ​​at different viewing angles on the imaging surface, the horizontal axis represents the half viewing angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 50% at the maximum half viewing angle, indicating that the optical lens has good relative illumination.

[0143] Figure 6 The MTF (Modulation Transfer Function) curve of Example 1 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. It can be seen from the figure that the MTF value of this embodiment is above 0.4 in the whole field of view, and in the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly 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 conditions.

[0144] Figure 7 The axial aberration curve of Example 1 is shown, 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. It can be seen from the figure that the offset of the axial aberration is controlled within -6μm to 6μm, indicating that the optical lens can correct the axial aberration well.

[0145] Figure 8 The vertical chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -4 μm to 8 μm, indicating that the optical lens can perfectly correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0146] Example 2

[0147] See also Fig. 9 , which is a schematic diagram of the structure of the optical lens provided in Embodiment 2 of the present invention, wherein the optical lens includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a prism G1, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G2.

[0148] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0149] The second lens L2 has negative refractive power, its object side surface S3 is convex, and its image side surface S4 is concave;

[0150] The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex;

[0151] The surface of the prism G1 facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface, and both the incident surface and the exit surface are planes;

[0152] The fourth lens L4 has positive refractive power, and its object-side surface S7 and image-side surface S8 are both convex surfaces;

[0153] Aperture ST;

[0154] The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave;

[0155] The sixth lens L6 has negative refractive power, and its object-side surface S11 and image-side surface S12 are both concave surfaces;

[0156] The seventh lens L7 has positive refractive power, and its object-side surface S13 and image-side surface S14 are both convex surfaces;

[0157] The eighth lens L8 has negative refractive power, and its object-side surface S14 and image-side surface S15 are both concave surfaces;

[0158] The seventh lens L7 and the eighth lens L8 form a cemented lens group, that is, the cemented surface between the image side surface of the seventh lens L7 and the object side surface of the eighth lens L8 is S14;

[0159] The object side surface S16 and the image side surface S17 of the filter G2 are both planes;

[0160] The imaging surface S18 is a plane.

[0161] The relevant parameters of each lens in the optical lens in Example 2 are shown in Table 2-1.

[0162] Table 2-1

[0163]

[0164] The surface parameters of the aspherical lens of the optical lens in Example 2 are shown in Table 2-2.

[0165] Table 2-2

[0166]

[0167]

[0168] See also Fig.10In 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 focal length, and its object side surface S19 is convex, and its image side surface S20 is concave. Relevant parameters are shown in Table 2-3.

[0169] Table 2-3

[0170]

[0171] Among them, the surface parameters of the aspheric surface of the protective lens are shown in Table 2-4.

[0172] Table 2-4

[0173] Face number K A B C D E F G H S19 0.00E+00 0.00E+00 -1.69E-05 7.28E-09 1.59E-11 -1.32E-13 -1.41E-16 5.45E-19 -2.18E-22 S20 0.00E+00 0.00E+00 -1.64E-05 9.96E-09 -1.17E-10 3.24E-13 -5.74E-16 -1.95E-19 1.30E-21

[0174] In this embodiment, the field curvature curve, F-Theta distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Fig.11 , Fig.12 , Fig.13 , Fig.14 , Fig.15 , Fig.16 shown.

[0175] Fig.11 The field curvature curve of Example 2 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, with the horizontal axis indicating the offset (unit: mm) and the vertical axis indicating the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.04mm to 0.08mm, indicating that the optical lens can correct the field curvature well.

[0176] Fig.12 The F-Theta distortion curve of Example 2 is shown, which represents the F-Theta distortion of light 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: °). It can be seen from the figure that the F-Theta distortion of the optical lens is controlled within -2% to 0, the image compression in the edge angle area is relatively gentle, and the clarity of the expanded image is effectively improved.

[0177] Fig.13 The relative illumination curve of Example 2 is shown, which represents the relative illumination values ​​at different viewing angles on the imaging surface, the horizontal axis represents the half viewing angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 50% at the maximum half viewing angle, indicating that the optical lens has good relative illumination.

[0178] Fig.14The MTF (Modulation Transfer Function) curve of Example 2 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. It can be seen from the figure that the MTF value of this embodiment is above 0.4 in the whole field of view, and in the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly 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 conditions.

[0179] Fig.15 The axial aberration curve of Example 2 is shown, 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. It can be seen from the figure that the offset of the axial aberration is controlled within -12μm to 6μm, indicating that the optical lens can correct the axial aberration well.

[0180] Fig.16 The vertical chromatic aberration curve of Example 2 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -4 μm to 7 μm, indicating that the optical lens can perfectly correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0181] Example 3

[0182] See also Fig.17 , which is a schematic diagram of the structure of the optical lens provided in Embodiment 3 of the present invention, wherein the optical lens includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a prism G1, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G2.

[0183] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0184] The second lens L2 has negative refractive power, its object side surface S3 is convex, and its image side surface S4 is concave;

[0185] The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex;

[0186] The surface of the prism G1 facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface, and both the incident surface and the exit surface are planes;

[0187] The fourth lens L4 has positive refractive power, and its object-side surface S7 and image-side surface S8 are both convex surfaces;

[0188] Aperture ST;

[0189] The fifth lens L5 has positive refractive power, and its object-side surface S9 and image-side surface S10 are both convex surfaces;

[0190] The sixth lens L6 has negative refractive power, and its object-side surface S10 and image-side surface S11 are both concave surfaces;

[0191] The fifth lens L5 and the sixth lens L6 form a cemented lens group, that is, the cemented surface between the image side surface of the fifth lens L5 and the object side surface of the sixth lens L6 is S10;

[0192] The seventh lens L7 has positive refractive power, and its object-side surface S12 and image-side surface S13 are both convex surfaces;

[0193] The eighth lens L8 has negative refractive power, and its object-side surface S13 and image-side surface S14 are both concave surfaces;

[0194] The seventh lens L7 and the eighth lens L8 form a cemented lens group, that is, the cemented surface between the image side surface of the seventh lens L7 and the object side surface of the eighth lens L8 is S13;

[0195] The object side surface S15 and the image side surface S16 of the filter G2 are both planes;

[0196] The imaging surface S17 is a plane.

[0197] The relevant parameters of each lens in the optical lens in Example 3 are shown in Table 3-1.

[0198] Table 3-1

[0199]

[0200] The surface parameters of the aspherical lens of the optical lens in Example 3 are shown in Table 3-2.

[0201] Table 3-2

[0202]

[0203]

[0204] See also Fig.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 focal length, and its object side surface S18 is convex, and its image side surface S19 is concave. Relevant parameters are shown in Table 3-3.

[0205] Table 3-3

[0206]

[0207] Among them, the surface parameters of the aspheric surface of the protective lens are shown in Table 3-4.

[0208] Table 3-4

[0209]

[0210] In this embodiment, the field curvature curve, F-Theta distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Fig.19 , Fig. 20 , Fig.21 , Fig. 22 , Fig.23 , Fig.24 shown.

[0211] Fig.19 The field curvature curve of Example 3 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset (unit: mm), and the vertical axis indicates the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within 0 to 0.04 mm, indicating that the optical lens can correct the field curvature well.

[0212] Fig. 20 The F-Theta distortion curve of Example 3 is shown, which represents the F-Theta distortion of light 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: °). It can be seen from the figure that the F-Theta distortion of the optical lens is controlled within -3% to 0, the image compression in the edge angle area is relatively gentle, and the clarity of the expanded image is effectively improved.

[0213] Fig.21 The relative illumination curve of Example 3 is shown, which represents the relative illumination values ​​at different viewing angles on the imaging surface, the horizontal axis represents the half viewing angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 50% at the maximum half viewing angle, indicating that the optical lens has good relative illumination.

[0214] Fig. 22The MTF (Modulation Transfer Function) curve of Example 3 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. It can be seen from the figure that the MTF value of this embodiment is above 0.4 in the whole field of view, and in the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly 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 conditions.

[0215] Fig.23 The axial aberration curve of Example 3 is shown, 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. It can be seen from the figure that the offset of the axial aberration is controlled within -15μm to 15μm, indicating that the optical lens can correct the axial aberration well.

[0216] Fig.24 The vertical chromatic aberration curve of Example 3 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1 μm to 1 μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0217] Example 4

[0218] See also Fig.25 , which is a schematic diagram of the structure of the optical lens provided in Embodiment 4 of the present invention, wherein the optical lens comprises, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a prism G1, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G2.

[0219] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0220] The second lens L2 has negative refractive power, its object side surface S3 is convex, and its image side surface S4 is concave;

[0221] The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex;

[0222] The surface of the prism G1 facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface, and both the incident surface and the exit surface are planes;

[0223] The fourth lens L4 has positive refractive power, and its object-side surface S7 and image-side surface S8 are both convex surfaces;

[0224] Aperture ST;

[0225] The fifth lens L5 has positive refractive power, and its object-side surface S9 and image-side surface S10 are both convex surfaces;

[0226] The sixth lens L6 has negative refractive power, and its object-side surface S11 and image-side surface S12 are both concave surfaces;

[0227] The seventh lens L7 has negative refractive power, its object-side surface S12 is convex, and its image-side surface S13 is concave;

[0228] The sixth lens L6 and the seventh lens L7 form a cemented lens group, that is, the cemented surface between the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is S12;

[0229] The eighth lens L8 has positive refractive power, its object-side surface S14 is convex, and its image-side surface S15 is concave;

[0230] The object side surface S16 and the image side surface S17 of the filter G2 are both planes;

[0231] The imaging surface S18 is a plane.

[0232] The relevant parameters of each lens in the optical lens in Example 4 are shown in Table 4-1.

[0233] Table 4-1

[0234]

[0235] The surface parameters of the aspherical lens of the optical lens in Example 4 are shown in Table 4-2.

[0236] Table 4-2

[0237]

[0238]

[0239] See also Fig.26 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 negative optical power, and its object side surface S19 is convex, and its image side surface S20 is concave. Relevant parameters are shown in Table 4-3.

[0240] Table 4-3

[0241]

[0242] In this embodiment, the field curvature curve, F-Theta distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Fig. 27 , Fig.28 , Fig.29 , Fig.30 , Fig.31 , Fig.32 shown.

[0243] Fig. 27 The field curvature curve of Example 4 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset (unit: mm), and the vertical axis indicates the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.04mm to 0mm, indicating that the optical lens can correct the field curvature well.

[0244] Fig.28 The F-Theta distortion curve of Example 4 is shown, which represents the F-Theta distortion of light 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: °). It can be seen from the figure that the F-Theta distortion of the optical lens is controlled within -2% to 2%, and the image compression in the edge angle area is relatively gentle, which effectively improves the clarity of the expanded image.

[0245] Fig.29 The relative illumination curve of Example 4 is shown, which represents the relative illumination values ​​at different viewing angles on the imaging surface, the horizontal axis represents the half viewing angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 40% at the maximum half viewing angle, indicating that the optical lens has a good relative illumination.

[0246] Fig.30 The MTF (Modulation Transfer Function) curve of Example 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. It can be seen from the figure that the MTF value of this embodiment is above 0.4 in the whole field of view, and in the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly 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 conditions.

[0247] Fig.31The axial aberration curve of Example 4 is shown, 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. It can be seen from the figure that the offset of the axial aberration is controlled within -20μm to 10μm, indicating that the optical lens can correct the axial aberration well.

[0248] Fig.32 The vertical chromatic aberration curve of Example 4 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -1 μm to 1 μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0249] Example 5

[0250] See also Fig.33 , which is a schematic diagram of the structure of the optical lens provided in Example 5 of the present invention, wherein the optical lens includes, in sequence from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, a prism G1, a fourth lens L4, an aperture ST, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G2.

[0251] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0252] The second lens L2 has negative refractive power, and its object-side surface S3 and image-side surface S4 are both concave;

[0253] The third lens L3 has positive refractive power, and its object-side surface S5 and image-side surface S6 are both convex;

[0254] The surface of the prism G1 facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface, and both the incident surface and the exit surface are planes;

[0255] The fourth lens L4 has positive refractive power, and its object-side surface S7 and image-side surface S8 are both convex surfaces;

[0256] Aperture ST;

[0257] The fifth lens L5 has positive refractive power, and its object-side surface S9 and image-side surface S10 are both convex surfaces;

[0258] The sixth lens L6 has negative refractive power, and its object-side surface S11 and image-side surface S12 are both concave surfaces;

[0259] The seventh lens L7 has negative refractive power, its object-side surface S12 is convex, and its image-side surface S13 is concave;

[0260] The sixth lens L6 and the seventh lens L7 form a cemented lens group, that is, the cemented surface between the image side surface of the sixth lens L6 and the object side surface of the seventh lens L7 is S12;

[0261] The eighth lens L8 has positive refractive power, its object-side surface S14 is convex, and its image-side surface S15 is concave;

[0262] The object side surface S16 and the image side surface S17 of the filter G2 are both planes;

[0263] The imaging surface S18 is a plane.

[0264] The relevant parameters of each lens in the optical lens in Example 5 are shown in Table 5-1.

[0265] Table 5-1

[0266]

[0267]

[0268] The surface parameters of the aspherical lens of the optical lens in Example 5 are shown in Table 5-2.

[0269] Table 5-2

[0270] Face number K A B C D E F S3 2.32E+01 0.00E+00 -2.10E-03 8.94E-05 -2.52E-06 3.88E-08 -2.40E-10 S4 -1.74E+00 0.00E+00 -7.38E-04 6.45E-05 -7.53E-07 -4.46E-08 1.32E-09 S7 0.00E+00 0.00E+00 -1.72E-03 -8.30E-05 8.54E-06 8.85E-07 1.50E-07 S8 0.00E+00 0.00E+00 4.50E-04 1.60E-04 7.60E-05 -1.88E-05 3.47E-06 S9 -9.96E+00 0.00E+00 2.71E-03 9.19E-04 -1.52E-03 6.23E-04 -1.19E-04 S10 -1.14E+01 0.00E+00 -2.13E-02 2.20E-03 2.10E-04 -2.51E-04 2.68E-05 S14 2.65E+00 0.00E+00 -4.83E-03 -8.71E-05 -2.18E-04 2.72E-05 -3.63E-06 S15 7.43E+00 0.00E+00 4.50E-03 6.12E-05 -1.86E-04 1.25E-05 -2.76E-07

[0271] See also Fig.34 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 focal length, and its object side surface S19 is convex, and its image side surface S20 is concave. Relevant parameters are shown in Table 5-3.

[0272] Table 5-3

[0273]

[0274] In this embodiment, the field curvature curve, F-Theta distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Fig.35 , Fig.36 , Fig.37 , Fig.38 , Fig.39 , Fig.40 shown.

[0275] Fig.35The field curvature curve of Example 5 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, with the horizontal axis indicating the offset (unit: mm) and the vertical axis indicating the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.05 to 0.02 mm, indicating that the optical lens can correct the field curvature well.

[0276] Fig.36 The F-Theta distortion curve of Example 5 is shown, which represents the F-Theta distortion of light 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: °). It can be seen from the figure that the F-Theta distortion of the optical lens is controlled within 0-8%, the image compression in the edge angle area is relatively gentle, and the clarity of the expanded image is effectively improved.

[0277] Fig.37 The relative illumination curve of Example 5 is shown, which represents the relative illumination values ​​at different viewing angles on the imaging surface, the horizontal axis represents the half viewing angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 40% at the maximum half viewing angle, indicating that the optical lens has a good relative illumination.

[0278] Fig.38 The MTF (Modulation Transfer Function) curve of Example 5 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. It can be seen from the figure that the MTF value of this embodiment is above 0.3 in the whole field of view, and in the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly 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 conditions.

[0279] Fig.39 The axial aberration curve of Example 5 is shown, 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. It can be seen from the figure that the offset of the axial aberration is controlled within -20μm to 15μm, indicating that the optical lens can correct the axial aberration well.

[0280] Fig.40The vertical chromatic aberration curve of Example 5 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -3 μm to 1 μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0281] Example 6

[0282] See also Fig.41 , which is a schematic diagram of the structure of the optical lens provided in Example 6 of the present invention. Compared with Example 5, this embodiment is different mainly in optical parameters such as the curvature radius of each lens surface and the lens thickness.

[0283] The relevant parameters of each lens in the optical lens in Example 8 are shown in Table 6-1.

[0284] Table 6-1

[0285]

[0286] The surface parameters of the aspherical lens of the optical lens in Example 6 are shown in Table 6-2.

[0287] Table 6-2

[0288]

[0289]

[0290] See also Fig.42 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 focal length, and its object side surface S19 is convex, and its image side surface S20 is concave. Relevant parameters are shown in Table 6-3.

[0291] Table 6-3

[0292]

[0293] In this embodiment, the field curvature curve, F-Theta distortion curve, relative illumination curve, MTF curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown as follows: Fig.43 , Fig.44 , Fig.45 , Fig.46 , Fig.47 , Fig.48 shown.

[0294] Fig.43The field curvature curve of Example 6 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, with the horizontal axis indicating the offset (unit: mm) and the vertical axis indicating the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.05 to 0.02 mm, indicating that the optical lens can correct the field curvature well.

[0295] Fig.44 The F-Theta distortion curve of Example 6 is shown, which represents the F-Theta distortion of light 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: °). It can be seen from the figure that the F-Theta distortion of the optical lens is controlled within 0-3%, the image compression in the edge angle area is relatively gentle, and the clarity of the expanded image is effectively improved.

[0296] Fig.45 The relative illumination curve of Example 6 is shown, which represents the relative illumination values ​​at different viewing angles on the imaging surface, the horizontal axis represents the half viewing angle (unit: °), and the vertical axis represents the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 40% at the maximum half viewing angle, indicating that the optical lens has a good relative illumination.

[0297] Fig.46 The MTF (Modulation Transfer Function) curve of Example 6 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. It can be seen from the figure that the MTF value of this embodiment is above 0.4 in the whole field of view, and in the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly 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 conditions.

[0298] Fig.47 The axial aberration curve of Example 6 is shown, 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. It can be seen from the figure that the offset of the axial aberration is controlled within -20μm to 10μm, indicating that the optical lens can correct the axial aberration well.

[0299] Fig.48The vertical chromatic aberration curve of Example 6 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within -2 μm to 1 μm, indicating that the optical lens can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0300] Please refer to Table 10, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the aperture value FNO, the real image height IH and the maximum field of view FOV of the optical lens, and the numerical values ​​corresponding to each conditional expression in each embodiment.

[0301] Table 10

[0302]

[0303]

[0304] In summary of the above embodiments, the optical lens provided by the present invention improves the imaging quality of the optical lens, reduces aberrations, and improves the imaging quality of the optical lens through the reasonable configuration of the surface shapes of each lens and the reasonable matching of the optical power.

[0305] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0306] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that: Along the optical axis from the object side to the imaging surface, it includes: The first lens has a negative optical power, and its object side surface is convex and its image side surface is concave; A second lens having negative optical power, whose image side surface is concave; The third lens has positive refractive power, and both the object side surface and the image side surface are convex; The fourth lens has positive refractive power, and both the object side surface and the image side surface are convex; a fifth lens having positive refractive power and a convex object side surface; The sixth lens has negative optical power, and both the object side surface and the image side surface are concave; a seventh lens having optical power and having a convex object side surface; an eighth lens having optical power and having an image side surface which is concave; The maximum field of view FOV of the optical lens satisfies: FOV>190°; The focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 0.8 <f1 / f2<1.6。 2. The optical lens according to claim 1, characterized in that: A reflective element is disposed between the third lens and the fourth lens, wherein the surface of the reflective element facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface.

3. The optical lens according to claim 1, characterized in that: A protective lens is provided between the first lens and the object side, wherein the object side of the protective lens is a convex surface and the image side is a concave surface.

4. The optical lens according to claim 1, characterized in that: The object side sag height Sag3 of the second lens and the object side semi-aperture d3 satisfy: -0.2 <Sag3 / d3<0。 5. The optical lens according to claim 1, characterized in that: The distance CT between the third lens and the fourth lens on the optical axis 34 The effective focal length f of the optical lens satisfies: 5.0 <CT 34 / f<7.

5.

6. The optical lens according to claim 1, characterized in that: The focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -1.0 <f2 / f3<-0.5。 7. The optical lens according to claim 1, characterized in that: 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。 8. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 5.0 <TTL / IH<7.0。 9. The optical lens according to claim 1, characterized in that: The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -6.0 <f1 / f<-4.0。 10. The optical lens according to claim 1, characterized in that: The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -5.0 <f2 / f<-3.5。

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