Optical lens

Abstract

The present invention provides an optical lens, which includes: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens in order from the object side to the imaging surface along the optical axis. The first lens has a negative focal power, the object side surface is a convex surface, and the image side surface is a concave surface. The second lens has a negative focal power, the object side surface is a concave surface, and the image side surface is a concave surface. The third lens has a positive focal power, the object side surface is a convex surface, and the image side surface is a convex surface. The fourth lens has a negative focal power, the object side surface is a concave surface, and the image side surface is a convex surface. The fifth lens has a positive focal power, the object side surface is a convex surface, and the image side surface is a convex surface. The sixth lens has a negative focal power, the object side surface is a concave surface, and the image side surface is a concave surface. The seventh lens has a positive focal power, the object side surface is a convex surface, and the image side surface is a convex surface. The eighth lens has a positive focal power, the object side surface is a convex surface, and the image side surface is a concave surface. The optical lens of the present invention has one or more advantages such as ultra-wide angle, large aperture, and high imaging quality.

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] Body cameras are mainly used to digitally record on-site conditions during law enforcement, such as video, photo, and audio recording, so that effective on-site image data can be provided afterwards. During on-site law enforcement, law enforcement officers need to record a large range of clear images, but the lenses of body cameras on the market either have too small an aperture, resulting in dark images, or have too small a field of view, which prevents them from recording too many images.

[0003] Therefore, how to make the lens of the body camera meet the requirements of high imaging quality while ensuring that the system has characteristics such as a large field of view and a large aperture is an urgent problem to be solved. Summary of the invention

[0004] In view of the above problems, an object of the present invention is to provide an optical lens having one or more advantages such as ultra-wide angle, large aperture, and high imaging quality.

[0005] The technical solution adopted by the present invention is:

[0006] An optical lens, composed of eight lenses, which include, from the object side to the imaging plane along the optical axis, a front group with negative optical power, a stop, and a rear group with positive optical power; the front group includes, from the object side to the imaging plane, a first lens, a second lens, a third lens, and a fourth lens; the rear group includes, from the object side to the imaging plane, a fifth lens, a sixth lens, a seventh lens, and an eighth lens;

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

[0008] The second lens has negative optical power, its object side surface is concave, and its image side surface is concave at the near optical axis;

[0009] The third lens has positive refractive power, its object side surface is convex, and its image side surface is convex;

[0010] The fourth lens has negative optical power, its object side surface is concave, and its image side surface is convex;

[0011] The fifth lens has positive refractive power, its object side surface is convex, and its image side surface is convex;

[0012] The sixth lens has negative optical power, its object side surface is concave, and its image side surface is concave;

[0013] The seventh lens has positive refractive power, its object side surface is convex, and its image side surface is convex;

[0014] The eighth lens has a positive optical power, its object side is convex, and its image side is concave;

[0015] Wherein, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.7 < TTL / IH < 2;

[0016] The focal length f1234 of the front group and the focal length f5678 of the rear group satisfy: -2 < f1234 / f5678 < -0.25.

[0017] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5 < TTL / f < 6.

[0018] Further preferably, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 2.5 < IH / f < 3.5.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.3; the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -0.4 < f1 / f8 < -0.03.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -4 < f2 / f < -1; the curvature radius R3 of the object side of the second lens and the curvature radius R4 of the image side of the second lens satisfy: -2 < R3 / R4 < -0.05.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1 < f3 / f < 3; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -7 < f4 / f < -3.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.4 < f6 / f < -1; the curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: -3.5 < R11 / R12 < -1.5.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1 < f7 / f < 1.5.

[0024] Further preferably, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -5 < f4 / f5 < -3.

[0025] More preferably, the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -1 < f6 / f7 < -0.8; the central thickness CT6 of the sixth lens and the central thickness CT7 of the seventh lens satisfy: 0.2 < CT6 / CT7 < 0.3.

[0026] More preferably, the effective aperture radius DM11 of the object side of the first lens and the effective aperture radius DM81 of the object side of the eighth lens satisfy: 0.95 < DM11 / DM81 < 1.05.

[0027] Compared with the prior art, the optical lens provided by the present invention has a short overall length and a large aperture through specific surface shape settings and reasonable optical power distribution, and can achieve high-definition imaging even in a dim environment. At the same time, it has an ultra-wide angle, so that more scene information can be obtained to meet the needs of large-range shooting. In addition, it can reasonably correct the overall aberration of the optical lens, achieve high-definition imaging, and improve the imaging quality of the optical lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0029] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 2 is an F-θ distortion curve diagram of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 3 is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 4 is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0033] Figure 5 is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0034] Figure 6 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 7 is an F-θ distortion curve diagram of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 8 is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0037] Fig. 9 is an axial aberration curve diagram of the optical lens in Embodiment 2 of the present invention.

[0038] Fig.10 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0039] Fig.11 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0040] Fig.12 4 is a F-θ distortion curve diagram of the optical lens in Example 3 of the present invention.

[0041] Fig.13 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0042] Fig.14 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0043] Fig.15 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0044] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] The optical lens provided in the embodiment of the present invention is composed of eight lenses, which include: a front group with negative focal power, an aperture, and a rear group with positive focal power from the object side to the imaging surface along the optical axis; the front group includes a first lens, a second lens, a third lens, and a fourth lens from the object side to the imaging surface; the rear group includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens from the object side to the imaging surface. It can be understood that the aperture is used to limit the amount of light entering to change the brightness of the image. When the aperture is located between the fourth lens and the fifth lens, it is convenient to correct the aperture aberration.

[0053] In some embodiments, the first lens has a negative optical power, its object side is convex, and its image side is concave. The second lens has a negative optical power, its object side is concave, and its image side is concave near the optical axis. The third lens has a positive optical power, its object side is convex, and its image side is convex. The fourth lens has a negative optical power, its object side is concave, and its image side is convex. The fifth lens has a positive optical power, its object side is convex, and its image side is convex. The sixth lens has a negative optical power, its object side is concave, and its image side is concave. The seventh lens has a positive optical power, its object side is convex, and its image side is convex. The eighth lens has a positive optical power, its object side is convex, and its image side is concave.

[0054] In some embodiments, the sixth lens and the seventh 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.

[0055] In some embodiments, the optical lens may further include a filter, and the filter may be disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0056] 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 of the optical lens satisfy: 1.7 < TTL / IH < 2. Meeting the above conditions, by reasonably restricting the ratio of the total length of the optical lens to the image height, it is ensured that the lens has a larger image plane under the same total length, achieving the balance between the miniaturization of the optical lens and the large image plane, and improving the market competitiveness.

[0057] In some embodiments, the focal length f1234 of the front group and the focal length f5678 of the rear group satisfy: -2 < f1234 / f5678 < -0.25. Meeting the above conditions, by reasonably setting the focal length relationship of each lens group before and after the aperture stop, the lens can have a larger field of view angle while correcting various aberrations of the optical lens and improving the imaging quality of the optical lens. It can be understood that the focal length of the front group is the combined focal length of the first lens, the second lens, the third lens, and the fourth lens. The focal length of the rear group is the combined focal length of the fifth lens, the sixth lens, the seventh lens, and the eighth lens.

[0058] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5 < TTL / f < 6. Meeting the above conditions can effectively limit the length of the lens, which is beneficial to the miniaturization of the optical lens.

[0059] 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 of the optical lens satisfy: 2.5 < IH / f < 3.5. Meeting the above conditions can endow the optical lens with the characteristic of a larger image plane, enabling better realization of the high-definition imaging quality of the lens.

[0060] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.3. Meeting the above conditions, by setting the first lens to have a large negative refractive power, it can be ensured that the first lens accommodates a larger angle of light and collects as much light as possible into the rear optical system, increasing the light flux while achieving a large field of view and better realizing the large aperture performance of the lens.

[0061] In some embodiments, the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -0.4 < f1 / f8 < -0.03. Meeting the above conditions, by reasonably setting the focal lengths and surface shapes of the first and last lenses in the lens, while ensuring that as much light as possible enters the system, the area of light entering the imaging plane is increased, which is beneficial to realizing large image plane imaging of the lens, and at the same time increasing the light input, to achieve large aperture imaging of the lens.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -4 < f2 / f < -1; the curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: -2 < R3 / R4 < -0.05. Meeting the above conditions, by reasonably setting the focal length and surface shape of the second lens, it can share the negative optical power at the front end of the optical lens, thereby facilitating the avoidance of excessive light deflection caused by the over-concentration of the optical power of the first lens and reducing the difficulty of aberration correction.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1 < f3 / f < 3. Meeting the above conditions, by reasonably setting the focal length of the third lens, the light can be effectively converged, reducing the difficulty of correcting the distortion of the edge field of view, ensuring that the lens has a small distortion while achieving a large field of view angle, and improving the overall imaging quality.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -7 < f4 / f < -3. Meeting the above conditions, by reasonably controlling the focal length of the fourth lens, the spherical aberration introduced by the front-end optical system can be effectively compensated, improving the overall imaging quality.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.4 < f6 / f < -1; the curvature radius R11 of the object side surface of the sixth lens and the curvature radius R12 of the image side surface of the sixth lens satisfy: -3.5 < R11 / R12 < -1.5. Meeting the above conditions, by reasonably setting the focal length and surface shape of the sixth lens, the aberration of the edge field of view can be effectively improved, and the overall imaging quality of the optical lens can be enhanced.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1 < f7 / f < 1.5. Meeting the above conditions, by reasonably setting the focal length of the seventh lens, it can cooperate better with the sixth lens to correct the chromatic aberration of the system and enhance the overall imaging quality.

[0067] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -5 < f4 / f5 < -3. Meeting the above conditions, by reasonably setting the focal length relationship between the fourth and fifth lenses, the edge distortion of the system can be effectively corrected, ensuring that the lens has a large field of view angle while having a small distortion, and enhancing the imaging clarity within the entire field of view.

[0068] In some embodiments, the focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -1 < f6 / f7 < -0.8; the central thickness CT6 of the sixth lens and the central thickness CT7 of the seventh lens satisfy: 0.2 < CT6 / CT7 < 0.3. Meeting the above conditions, by reasonably setting the focal length and thickness relationship of the doublet lens, on the one hand, the chromatic aberration of the system can be effectively corrected and the imaging quality can be improved, and at the same time, the image quality of the optical system can be effectively improved, the light energy loss can be reduced, and the imaging clarity can be increased.

[0069] In some embodiments, the clear aperture radius DM11 of the object side surface of the first lens and the clear aperture radius DM81 of the object side surface of the eighth lens satisfy: 0.95 < DM11 / DM81 < 1.05. Meeting the above conditions, the lens has a large aperture, which can better achieve large-angle light collection, realize the ultra-wide-angle imaging of the lens, and at the same time can increase the imaging area of the lens and realize the large-format imaging of the lens.

[0070] In some embodiments, the back focal length BFL of the optical lens and the total optical length TTL of the optical lens satisfy: 0.15 < BFL / TTL < 0.2; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.9 < BFL / f < 1.2. Meeting the above conditions, the lens can have an appropriate back focus, ensuring the compatibility between the lens and the camera body while making the structure of the lens more compact.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.2 < f5 / f < 2; the curvature radius R9 of the object side surface of the fifth lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: -1.5 < R9 / R10 < -1. Meeting the above conditions, by reasonably controlling the focal length and surface shape of the fifth lens, it is beneficial to converge light while correcting the field curvature and distortion of the optical lens, and improving the imaging quality of the optical lens.

[0072] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 4.5 < f8 / f < 30. Meeting the above conditions, the eighth lens has a positive refractive power, which is beneficial to converge the diverging light to the rear optical system, can shorten the optical path of the peripheral light reaching the imaging surface, thereby improving the resolution quality.

[0073] In some embodiments, the curvature radius R7 of the object side surface of the fourth lens and the curvature radius R8 of the image side surface of the fourth lens satisfy: 0.6 < R7 / R8 < 0.7. Meeting the above conditions, the fourth lens adopts a meniscus shape with a relatively balanced thickness, which can effectively reduce the optical path difference between the center and the periphery of the lens, and is beneficial to correcting the distortion of the optical lens.

[0074] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the F-number Fno of the optical lens satisfy: 4.6 mm < IH / Fno < 5.2 mm. Meeting the above conditions is beneficial to achieving the balance of the large target surface and large aperture of the lens.

[0075] In some embodiments, the focal length f1234 of the front lens group and the effective focal length f of the optical lens satisfy: -4 < f1234 / f < -1.2. Meeting the above conditions, by setting the front diaphragm lens group to have a large negative refractive power, it is beneficial for large-angle light to enter the system to achieve a large field of view angle of the system, and it is also beneficial to improve the light flux of the system and better achieve the large aperture of the lens.

[0076] In some embodiments, the focal length f5678 of the rear lens group and the effective focal length f of the optical lens satisfy: 1.3 < f5678 / f < 5. Meeting the above conditions, by reasonably setting the positive refractive power of the rear diaphragm lens group, it is beneficial to balance the distortion and astigmatism generated by the front-end lens of the optical lens, and improve the imaging quality of the optical lens.

[0077] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the eighth lens along the optical axis respectively and the optical total length TTL of the optical lens satisfy: 0.5 < ∑CT / TTL < 0.6. Meeting the above conditions can effectively compress the total length of the optical lens, and is beneficial to the structural design and production process of the optical lens.

[0078] In some embodiments, the central thickness CT2 of the second lens and the central thickness CT3 of the third lens satisfy: 0.3 < CT2 / CT3 < 1.5. By satisfying the above conditions, through reasonable setting of the central thicknesses of the second and third lenses, the processing difficulty of the lens can be reduced and the assembly yield can be improved; at the same time, the aberration of the lens can be effectively corrected and the imaging quality can be improved.

[0079] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the chief ray angle of incidence CRA at the maximum image height of the optical lens satisfy: 0.7 mm / ° < IH / CRA < 1 mm / ° . By satisfying the above conditions, the lens can have a larger image plane and at the same time can match a smaller CRA imaging chip to achieve high-definition imaging.

[0080] In some embodiments, the optical lens satisfies the conditional formula: 16 mm < TTL < 18 mm, 2.5 mm < f < 4 mm, 9 mm < IH < 10 mm, Fno < 2, 160° < FOV < 180°; 9° < CRA < 13°; where TTL represents the overall optical length of the optical lens, f represents the effective focal length of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, Fno represents the aperture value of the optical lens, FOV represents the maximum field of view angle of the optical lens, and CRA represents the chief ray angle of incidence at the maximum image height of the optical lens. By satisfying the above conditions, it shows that the optical lens provided by the embodiments of the present invention has the characteristics of ultra-wide angle, so that more scene information can be obtained to meet the needs of large-range shooting; it is beneficial to realize the large-aperture characteristics of the lens to ensure clear shooting in a relatively dark environment; it can make the CRA of the optical lens have a large allowable error range from the CRA of the chip photosensitive element, and improve the adaptability of the optical lens to the image sensor.

[0081] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low-dispersion characteristics of the glass itself. The first lens and the fifth lens in the optical lens provided by the present invention are made of glass lenses, and the second lens, the third lens, the fourth lens, the sixth lens, the seventh lens and the eighth lens are made of plastic lenses.

[0082] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens may be spherical lenses or aspherical lenses. Compared with spherical structures, aspherical structures can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and reducing the size of lenses, and better realizing the miniaturization of lenses. More specifically, the first lens of the present invention adopts a spherical lens, and the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can all adopt aspherical lenses, which can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and reducing the size of lenses, and better realizing the miniaturization of lenses.

[0083] In various embodiments of the present invention, when the lens is an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0084] ;

[0085] Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients respectively.

[0086] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate 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.

[0087] Example 1

[0088] See also Figure 1 , which is a schematic diagram of the structure of an optical lens 100 provided in Embodiment 1 of the present invention, the optical lens 100 includes, from the object side to the imaging surface along the optical axis, a front group with negative optical power, a stop ST, a rear group with positive optical power, and a filter G1. The front group includes, from the object side to the imaging surface, a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. The rear group includes, from the object side to the imaging surface, a fifth lens L5, a sixth lens L6, a seventh lens L7, and an eighth lens L8.

[0089] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0090] The second lens L2 has negative refractive power, its object side surface S3 is concave, and its image side surface S4 is concave at the near optical axis;

[0091] The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is convex;

[0092] The fourth lens L4 has negative refractive power, its object-side surface S7 is concave, and its image-side surface S8 is convex;

[0093] The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is convex;

[0094] The sixth lens L6 has negative refractive power, its object-side surface S11 is concave, and its image-side surface S12 is concave;

[0095] The seventh lens L7 has positive refractive power, its object-side surface S12 is convex, and its image-side surface S13 is convex;

[0096] The sixth lens L6 and the seventh lens L7 form a cemented lens group with positive refractive power, 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;

[0097] The eighth lens L8 has positive refractive power, its object-side surface S14 is convex, and its image-side surface S15 is concave;

[0098] The object side surface S16 and the image side surface S17 of the filter G1 are both planes;

[0099] The imaging surface S18 is a plane.

[0100] The first lens L1 is a glass spherical lens, the fifth lens L5 is a glass aspherical lens, and the second lens L2, the third lens L3, the fourth lens L4, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are all plastic aspherical lenses.

[0101] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0102] Table 1-1

[0103]

[0104] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0105] Table 1-2

[0106]

[0107] Figure 2The F-θ distortion curve of the optical lens 100 in this embodiment is shown, which represents the distortion of different field angles on the imaging surface, the horizontal axis represents the distortion value (unit: %), and the vertical axis represents the field angle (unit: °). It can be seen from the figure that the distortion value is controlled within ±2%, indicating that the optical lens 100 can correct the distortion well.

[0108] Figure 3 The field curvature curve of the optical lens 100 in this embodiment is shown, which represents the field curvature of light in the meridional image plane and the sagittal image plane, the horizontal axis represents the offset (unit: mm), and the vertical axis represents the 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 ±0.1mm, indicating that the optical lens 100 can correct the field curvature well.

[0109] Figure 4 The axial aberration curve of the optical lens 100 in this embodiment 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: mm), 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 ±0.03mm, indicating that the optical lens 100 can correct the axial aberration well.

[0110] Figure 5 The vertical axis chromatic aberration curve of the optical lens 100 in this embodiment 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 axis 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 axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±9 μm, indicating that the optical lens 100 can correct chromatic aberration well.

[0111] Example 2

[0112] See also Figure 6 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0113] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0114] Table 2-1

[0115]

[0116] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0117] Table 2-2

[0118]

[0119] In this embodiment, the F-θ distortion curve, field curvature curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens 200 are respectively as follows: Figure 7 , Figure 8 , Fig. 9 , Fig.10 shown.

[0120] from Figure 7 It can be seen that the distortion value is controlled within ±5%, indicating that the optical lens 200 can correct the distortion well.

[0121] from Figure 8 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 200 can correct the field curvature well.

[0122] from Fig. 9 It can be seen that the offset of the axial aberration is controlled within ±0.04 mm, indicating that the optical lens 200 can correct the axial aberration well.

[0123] from Fig.10 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±9μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0124] Example 3

[0125] See also Fig.11 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0126] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0127] Table 3-1

[0128]

[0129] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0130] Table 3-2

[0131]

[0132] In this embodiment, the F-θ distortion curve, field curvature curve, axial aberration curve, and vertical axis chromatic aberration curve of the optical lens 300 are respectively as follows: Fig.12 , Fig.13 , Fig.14 , Fig.15 shown.

[0133] from Fig.12 It can be seen that the distortion value is controlled within ±5%, indicating that the optical lens 300 can correct the distortion well.

[0134] from Fig.13 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.2mm, indicating that the optical lens 300 can correct the field curvature well.

[0135] from Fig.14 It can be seen that the offset of the axial aberration is controlled within ±0.05 mm, indicating that the optical lens 300 can correct the axial aberration well.

[0136] from Fig.15 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±8μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0137] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view angle, the chief ray incident angle CRA at the maximum image height, the combined focal length f67 of the sixth lens and the seventh lens, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0138] Table 4

[0139]

[0140]

[0141] In summary, the optical lens provided by the present invention has at least the following advantages:

[0142] (1) Through specific surface shape settings and reasonable optical focal length distribution, the lens has a large aperture, which can achieve high-definition imaging even in dim environments. At the same time, it has an ultra-wide angle, so that more scene information can be obtained, meeting the needs of large-scale shooting.

[0143] (2) The optical lens of the present invention can reasonably correct the overall aberration of the optical lens, achieve high-definition imaging, and improve the imaging quality of the optical lens.

[0144] (3) The glass-plastic hybrid structure improves the stability of the lens under high and low temperature conditions while also improving the imaging quality. At the same time, the lens has a smaller CRA, which can match the chip well and ensure good resolution quality.

[0145] 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.

[0146] 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, consisting of eight lenses, characterized in that: Along the optical axis from the object side to the imaging plane, it sequentially includes: a front group with a negative optical power, a diaphragm, and a rear group with a positive optical power; the front group sequentially includes a first lens, a second lens, a third lens, and a fourth lens from the object side to the imaging plane; the rear group sequentially includes a fifth lens, a sixth lens, a seventh lens, and an eighth lens from the object side to the imaging plane; The first lens has a negative optical power, its object side is convex, and its image side is concave; The second lens has a negative optical power, its object side is concave, and its image side is concave near the optical axis; The third lens has a positive optical power, its object side is convex, and its image side is convex; The fourth lens has a negative optical power, its object side is concave, and its image side is convex; The fifth lens has a positive optical power, its object side is convex, and its image side is convex; The sixth lens has a negative optical power, its object side is concave, and its image side is concave; The seventh lens has a positive optical power, its object side is convex, and its image side is convex; The eighth lens has a positive optical power, its object side is convex, and its image side is concave; Wherein, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.7 < TTL / IH < 2; The focal length f1234 of the front group and the focal length f5678 of the rear group satisfy: -2 < f1234 / f5678 < -0.

25.

2. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5.5 < TTL / f < 6.

3. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3.015 ≤ IH / f ≤ 3.

102.

4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2 < f1 / f < -1.3; the focal length f1 of the first lens and the focal length f8 of the eighth lens satisfy: -0.4 < f1 / f8 < -0.

03.

5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -4 < f2 / f < -1; the curvature radius R3 of the object side of the second lens and the curvature radius R4 of the image side of the second lens satisfy: -2 < R3 / R4 < -0.

05.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1 < f3 / f < 3; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -7 < f4 / f < -3.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.4 < f6 / f < -1; the curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: -3.5 < R11 / R12 < -1.

5.

8. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1 < f7 / f < 1.

5.

9. The optical lens according to claim 1, characterized in that: The focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -5 < f4 / f5 < -3.

10. The optical lens according to claim 1, characterized in that: The focal length f6 of the sixth lens and the focal length f7 of the seventh lens satisfy: -1 < f6 / f7 < -0.8; the central thickness CT6 of the sixth lens and the central thickness CT7 of the seventh lens satisfy: 0.2 < CT6 / CT7 < 0.

3.

11. The optical lens according to claim 1, characterized in that: The clear aperture semi-diameter DM11 of the object side of the first lens and the clear aperture semi-diameter DM81 of the object side of the eighth lens satisfy: 0.95 < DM11 / DM81 < 1.05.

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