Optical lens

Abstract

The application provides an optical lens which is composed of eight lenses and sequentially comprises, along an optical axis from an object side to an imaging surface, a first lens with negative optical power, the object side of which is a convex surface and the image side of which is a concave surface; a second lens with negative optical power, the object side of which is a concave surface and the image side of which is a concave surface; a third lens with positive optical power, the object side of which is a convex surface and the image side of which is a concave surface; a fourth lens with negative optical power, the object side of which is a convex surface and the image side of which is a concave surface; a fifth lens with positive optical power, the object side of which is a convex surface and the image side of which is a convex surface; a sixth lens with negative optical power; a seventh lens with positive optical power, the image side of which is a convex surface; and an eighth lens with negative optical power. The optical lens provided by the application can improve the imaging quality of the optical lens, and the optical lens has one or more advantages such as a large field of view, a large aperture, high imaging quality and the like.

Description

Technical Field

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

[0002] Law enforcement recorders are primarily used to digitally record the situation at the scene during law enforcement, such as taking videos, photos, and audio recordings, so that effective on-site video data can be provided afterward. During on-site law enforcement, law enforcement officers need to record a wide range of clear images; however, the lenses of law enforcement recorders on the market either record unclear images or have too small a field of view, which prevents them from recording too much footage.

[0003] Therefore, how to ensure high imaging quality in law enforcement recorder lenses is a problem that urgently needs to be solved. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide an optical lens with the advantage of excellent image quality.

[0005] The technical solution adopted in this invention is as follows:

[0006] An optical lens, comprising eight lenses, arranged sequentially along the optical axis from the object side to the imaging plane:

[0007] The first lens with negative optical power has a convex object side and a concave image side.

[0008] A second lens with negative optical power has a concave object side and a concave image side.

[0009] A third lens with positive optical power has a convex object-side surface and a concave image-side surface.

[0010] The fourth lens with negative optical power has a convex object side and a concave image side.

[0011] The fifth lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0012] A sixth lens with negative optical power;

[0013] The seventh lens, which has positive optical power, has a convex image-side surface;

[0014] An eighth lens with negative optical power;

[0015] Wherein, the object-side radius of curvature R5 of the third lens and the image-side radius of curvature R6 of the third lens satisfy: -1<(R5-R6) / (R5+R6)<-0.4; the object-side radius of curvature R3 of the second lens and the image-side radius of curvature R4 of the second lens satisfy: -0.9<(R3+R4) / (R3-R4)<0.

[0016] It is further preferred that the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6<TTL / f<8.5; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 2.5<TTL / IH<3.9.

[0017] It is further preferred that the maximum field of view FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 70°<FOV / FNO<85°; the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4<IH / EPD<5.5.

[0018] It is further preferred that the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2<IH / f<2.8; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.7<BFL / f<0.9.

[0019] It is further preferred that the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.3<f2 / f<-2.1, the effective focal length f of the optical lens and the radius of curvature R3 of the object side surface of the second lens satisfy: -4.4<R3 / f<-2.4, and the effective focal length f of the optical lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 3.5<R4 / f<40.

[0020] It is further preferred that the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.7<f3 / f<3.3, the effective focal length f of the optical lens and the radius of curvature R5 of the object side surface of the third lens satisfy: 1.1<R5 / f<1.5, and the effective focal length f of the optical lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 3.2<R6 / f<85.

[0021] It is further preferred that the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.9<f6 / f<-1.2, and the radius of curvature R11 of the object side surface of the sixth lens and the radius of curvature R12 of the image side surface of the sixth lens satisfy: 0<R11 / R12<10.5.

[0022] It is further preferred that the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.15<f7 / f<3.6, and the radius of curvature R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -3.7<R14 / f<-1.2.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -25 < f8 / f < -4.2, and the radius of curvature R15 of the object-side surface of the eighth lens and the radius of curvature R16 of the image-side surface of the eighth lens satisfy: 0 < R16 / R15 < 400.

[0024] Further preferably, the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -9 < f123 / f45678 < -2.2; the clear aperture half-diameter d1 of the object-side surface of the first lens and the clear aperture half-diameter d16 of the image-side surface of the eighth lens satisfy: 1.6 < d1 / d16 < 2.4. Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical power, and through matching of specific surface shapes and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, improve the imaging quality of the optical lens, and enable the lens to have one or more advantages such as large field of view, large aperture and high imaging quality. Description of Drawings

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of embodiments in conjunction with the following drawings, in which:

[0026] Figure 1 is a structural schematic diagram of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 2 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 is a vertical chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 is an MTF (Modulation Transfer Function) curve diagram of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 6 is a relative illuminance curve diagram of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 7 is a structural schematic diagram of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 9 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 10 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 11 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 12 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0038] Figure 13 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0039] Figure 14 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 15 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0041] Figure 16 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 17 This is the MTF curve of the optical lens in Embodiment 3 of the present invention.

[0043] Figure 18 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0044] Figure 19 This is a schematic diagram of the optical lens in Embodiment 4 of the present invention.

[0045] Figure 20 This is the F-Tan (Theta) distortion curve of the optical lens in Embodiment 4 of the present invention.

[0046] Figure 21 This is an axial aberration curve of the optical lens in Embodiment 4 of the present invention.

[0047] Figure 22 This is a chromatic aberration curve of the optical lens in Embodiment 4 of the present invention.

[0048] Figure 23 This is the MTF curve of the optical lens in Embodiment 4 of the present invention.

[0049] Figure 24 This is a relative illumination curve of the optical lens in Embodiment 4 of the present invention.

[0050] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0051] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of embodiments of this application and are not intended to limit the scope of this 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.

[0052] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0053] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0054] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity 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 location of the concaveness 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 subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0055] It should also be understood that the terms "comprising," "including," "having," "containing," 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. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0056] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0057] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0058] The optical lens provided in this embodiment of the invention consists of eight lenses, which are arranged sequentially along the optical axis from the object side to the imaging plane as 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.

[0059] In some embodiments, the first lens may have negative optical power, with its object-side surface being convex and its image-side surface being concave. The second lens may have negative optical power, with both its object-side and image-side surfaces being concave. The third lens may have positive optical power, with both its object-side and image-side surfaces being convex. The fourth lens may have negative optical power, with both its object-side and image-side surfaces being concave. The fifth lens may have positive optical power, with both its object-side and image-side surfaces being convex. The sixth lens may have negative optical power, with both its object-side and image-side surfaces being either concave or convex. The seventh lens may have positive optical power, with both its object-side and image-side surfaces being either concave or convex. The eighth lens may have negative optical power, with both its object-side and image-side surfaces being either concave or convex.

[0060] In some embodiments, the optical lens may also include an aperture stop, which may be located between the third and fourth lenses. It is understood that the aperture stop can be used to limit the amount of light entering the lens to change the brightness of the image.

[0061] In some embodiments, the optical lens may further include a filter, which may be disposed between the eighth lens and the imaging surface. The filter is used to filter out interfering light and prevent interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0062] In some embodiments, the sixth and seventh lenses can be cemented together to form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberrations 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.

[0063] In some embodiments, the curvature radius R5 of the object-side surface of the third lens and the curvature radius R6 of the image-side surface of the third lens satisfy: -1<(R5-R6) / (R5+R6)<-0.4; 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: -0.9<(R3+R4) / (R3-R4)<0. Satisfying the above ranges can correct the aberration of the optical lens, ensure the stable propagation trend of light passing through the second lens and the third lens, reduce the tolerance sensitivity of the optical lens, and facilitate the smooth entry of light into the rear lenses. More specifically, -0.98<(R5-R6) / (R5+R6)<-0.44; -0.88<(R3+R4) / (R3-R4)<-0.01.

[0064] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6<TTL / f<8.5; the total optical length TTL of the optical lens and the actual image height IH corresponding to the maximum field of view of the optical lens satisfy: 2.5<TTL / IH<3.9. Satisfying the above ranges, by reasonably controlling the total length, focal length and image height of the optical lens, it helps the optical lens achieve a balance between total length and volume, and is beneficial to improving the structural stability of the optical lens. More specifically, 6.69<TTL / f<7.82, 2.78<TTL / IH<3.58.

[0065] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 70°<FOV / FNO<85°; the actual image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4<IH / EPD<5.5. Satisfying the above ranges helps achieve the characteristics of large field of view and large aperture of the optical lens, increases the amount of light passing through, and improves the relative illumination. More specifically, 72°<FOV / FNO<81°, 4.32<IH / EPD<5.14.

[0066] In some embodiments, the actual image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2<IH / f<2.8; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.7<BFL / f<0.9. Satisfying the above ranges can reasonably control the image height, focal length and back focal length of the optical lens. Under the condition of a fixed focal length, the optical lens can obtain the characteristics of a large target surface and a long back focal length. The characteristic of the large target surface helps the optical lens improve imaging quality, and the characteristic of the long back focal length can meet the arrangement requirements of the rear chip and reduce the difficulty of assembly and processing. More specifically, 2.15<IH / f<2.58, 0.73<BFL / f<0.86.

[0067] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3.3 < f2 / f < -2.1; the effective focal length f of the optical lens and the radius of curvature R3 of the object-side surface of the second lens satisfy: -4.4 < R3 / f < -2.4; the effective focal length f of the optical lens and the radius of curvature R4 of the image-side surface of the second lens satisfy: 3.5 < R4 / f < 40. Satisfying the above ranges enables the second lens to have appropriate negative optical power and reasonable surface shape collocation, which helps divergent light enter each subsequent lens smoothly and keeps the light trend stable. More specifically, -3.06 < f2 / f < -2.29, -4 < R3 / f < -2.62, 3.8 < R4 / f < 36.88.

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 1.7 < f3 / f < 3.3; the effective focal length f of the optical lens and the radius of curvature R5 of the object-side surface of the third lens satisfy: 1.1 < R5 / f < 1.5; the effective focal length f of the optical lens and the radius of curvature R6 of the image-side surface of the third lens satisfy: 3.2 < R6 / f < 85. Satisfying the above ranges enables the third lens to have appropriate positive optical power and surface shape, which facilitates light convergence, and the gentle shape of the lens is beneficial to reducing volume and cutting cost. More specifically, 1.9 < f3 / f < 3.04; 1.2 < R5 / f < 1.35; 3.51 < R6 / f < 79.55.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1.9 < f6 / f < -1.2; the radius of curvature R11 of the object-side surface of the sixth lens and the radius of curvature R12 of the image-side surface of the sixth lens satisfy: 0 < R11 / R12 < 10.5. Satisfying the above ranges, 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. More specifically, -1.76 < f6 / f < -1.31; 0.06 < R11 / R12 < 9.75.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.15 < f7 / f < 3.6; the radius of curvature R14 of the image-side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -3.7 < R14 / f < -1.2. Satisfying the above ranges, by reasonably setting the focal length and surface shape of the seventh lens, it can cooperate with the sixth lens to better correct the chromatic aberration of the system and improve the overall imaging quality. More specifically, 1.28 < f7 / f < 3.3; -3.43 < R14 / f < -1.32.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -25 < f8 / f < -4.2, and the radius of curvature R15 of the object-side surface of the eighth lens and the radius of curvature R16 of the image-side surface of the eighth lens satisfy: 0 < R16 / R15 < 400. Satisfying the above ranges, reasonably controlling the focal length proportion and surface profile of the eighth lens helps to control the stable propagation trend of light to the image surface, obtain the characteristic of large target surface, enable the optical lens to ensure high resolution capability on the basis of eliminating ghost images, and improve the imaging quality of the optical lens. More specifically, -22.94 < f8 / f < -4.66; 0.68 < R16 / R15 < 381.94.

[0072] In some embodiments, the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -9 < f123 / f45678 < -2.2. Satisfying the above range, by reasonably setting the focal length relationship of the lens groups before and after the diaphragm, it is beneficial to balance the distortion and astigmatism generated by the optical lens, and improve the imaging quality of the optical lens. More specifically, -8.35 < f123 / f45678 < -2.4.

[0073] In some embodiments, the clear half-aperture d1 of the object-side surface of the first lens and the clear half-aperture d16 of the image-side surface of the eighth lens satisfy: 1.6 < d1 / d16 < 2.4. Satisfying the above range, by controlling the aperture ratio of the front and rear lenses, the propagation trend of light is limited within a reasonable range, so that the illuminance of the imaging surface is uniform. More specifically, 1.79 < d1 / d16 < 2.18.

[0074] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV, and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 60° < f×FOV / IH < 80°. Satisfying the above range, by reasonably limiting the relationship among the focal length, the field of view and the image height of the optical lens, it is beneficial to realize the balance between large field of view and large target surface imaging of the optical lens. More specifically, 62.36° < f×FOV / IH < 74°.

[0075] In some embodiments, the clear half-aperture d1 of the object-side surface of the first lens, the real image height IH corresponding to the maximum field of view of the optical lens, and the maximum field of view FOV of the optical lens satisfy: 0.3 < d1 / (IH / 2) / tan(FOV / 2) < 0.7. Satisfying the above range, the optical lens can have a large field of view and a large image surface while having a small front aperture. More specifically, 0.31 < d1 / (IH / 2) / tan(FOV / 2) < 0.65.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2.5 < f1 / f < -1.6. Meeting the above range enables the first lens to have a suitable negative optical power, which helps collect light with large field angles entering the optical lens as much as possible, obtain more image information, control the trend of edge large-angle light, and improve the imaging quality of the optical lens. More specifically, -2.36 < f1 / f < -1.79.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -18 < f4 / f < -4.2; the radius of curvature R7 of the object-side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 0.9 < R7 / f < 2.7; the radius of curvature R8 of the image-side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6 < R8 / f < 1.4. Meeting the above range, by reasonably controlling the focal length proportion and surface shape of the fourth lens, it helps collect the light emitted from the front lenses, enable the collected light to enter each subsequent lens smoothly, and improve the resolution capability of the optical lens. More specifically, -16.2 < f4 / f < -4.67; 0.97 < R7 / f < 2.45; 0.7 < R8 / f < 1.3.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1 < f5 / f < 1.65. Meeting the above range, by reasonably controlling the focal length proportion of the fifth lens, it helps smooth the propagation trend of light from the front lenses, correct the aberration generated by the front lenses, and improve the imaging quality. More specifically, 1.05 < f5 / f < 1.51.

[0079] In some embodiments, the combined focal length f123 of the first lens, the second lens and the third lens and the effective focal length f of the optical lens satisfy: -19 < f123 / f < -3.3; the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and the effective focal length f of the optical lens satisfy: 1.4 < f45678 / f < 2.3. Meeting the above range, by reasonably setting the focal lengths of the lens groups before and after the diaphragm, it helps balance the distortion and astigmatism generated by the optical lens, and improve the imaging quality of the optical lens. More specifically, -17.99 < f123 / f < -3.64; 1.5 < f45678 / f < 2.17.

[0080] In some embodiments, the optical lens satisfies the following conditional expressions: 2.3mm < f < 2.9mm, 1.1mm < EPD < 1.5mm, 17mm < TTL < 21mm, 1.7 < FNO < 2.2, 14° < CRA < 20°, 1.8mm < BFL < 2.4mm, 140° < FOV < 170°, 5mm < IH < 7mm; wherein, f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, FNO represents the f-number of the optical lens, CRA represents the incident angle of the chief ray at the maximum image height of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field of view of the optical lens, and IH represents the real image height corresponding to the maximum field of view of the optical lens. Satisfying the above conditions indicates that the optical lens provided by the embodiment of the present invention has at least the characteristics of large field of view, large aperture, high imaging quality, etc. More specifically, 2.51mm < f < 2.69mm, 1.25mm < EPD < 1.42mm, 17.9mm < TTL < 20.1mm, 1.8 < FNO < 2.1, 14.74° < CRA < 19.91°, 1.91mm < BFL < 2.26mm, 145° < FOV < 161°, 5.59mm < IH < 6.46mm.

[0081] In some embodiments, the lenses in the optical lens provided by the present invention may be made of glass or plastic. When the lens is made of plastic, the production cost can be effectively reduced. When the lens is made of glass, the low dispersion property of glass itself can be used to effectively correct the geometric chromatic aberration of the optical system. In the optical lens provided by the present invention, the first lens, the second lens, the fifth lens, the sixth lens and the seventh lens are glass lenses, and the third lens, the fourth lens and the eighth lens are 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 the size of the lens, and better realizing the miniaturization of the lens. More specifically, in the present invention, the third lens, the fourth lens, the fifth lens and the eighth lens are aspherical lenses, and the first lens, the second lens, the sixth lens and the seventh lens are spherical lenses.

[0083] In various embodiments of the present invention, when an aspherical lens is used as a lens, the shape of each aspheric surface of the optical lens satisfies the following equation:

[0084] ;

[0085] Where 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 vertex of the surface, K is the quadratic surface coefficient, and B, C, D, E, F, G, and H are the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth order surface coefficients, respectively.

[0086] The present invention will be further described below with reference to several 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 tables of each embodiment. The following embodiments are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention.

[0087] Example 1

[0088] Please see Figure 1 The diagram shown is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens includes, in sequence along the optical axis from the object side to the imaging plane: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, and a filter G1.

[0089] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0090] The second lens L2 has negative optical power, its object side S3 is concave, and its image side S4 is concave.

[0091] The third lens L3 has positive optical power, its object side S5 is convex, and its image side S6 is concave.

[0092] The fourth lens L4 has negative optical power, its object side S7 is convex, and its image side S8 is concave.

[0093] The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side S10 is convex.

[0094] The sixth lens L6 has negative optical power, its object side S11 is convex, and its image side is concave.

[0095] The seventh lens L7 has positive optical power, its object side is convex, and its image side S13 is convex.

[0096] The sixth lens L6 and the seventh lens L7 form a cemented lens group with positive optical power, that is, the cemented surface of the image side of the sixth lens L6 and the object side of the seventh lens L7 is S13.

[0097] The eighth lens L8 has negative optical power, its object side S14 is concave, and its image side S15 is convex.

[0098] The object-side surface S16 and the image-side surface S17 of filter G1 are both planar.

[0099] The imaging plane S18 is a plane.

[0100] The first lens L1, the second lens L2, the sixth lens L6 and the seventh lens L7 are all glass spherical lenses, the fifth lens L5 is a glass aspherical lens, and the third lens L3, the fourth lens L4 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 profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0105] Table 1-2

[0106]

[0107] The line graph represents the distortion at different field-of-view angles on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the graph, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 100 can correct distortion well.

[0108] Figure 3 The diagram shows the axial aberration curve of the optical lens 100 in this embodiment, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the axial aberration offset is controlled within -0.07 mm to 0.04 mm, indicating that the optical lens 100 can correct axial aberration well.

[0109] Figure 4 The diagram shows the transverse chromatic aberration curve of the optical lens 100 in this embodiment. It represents the chromatic aberration of each wavelength relative to the center wavelength (0.555 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within -1 μm to 4 μm, indicating that the optical lens 100 can effectively correct chromatic aberration.

[0110] Figure 5 The modulation transfer function (MTF) curve of the optical lens 100 in this embodiment is shown, which represents the lens imaging modulation at different spatial frequencies in each field of view. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this embodiment is above 0.4 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, exhibiting good imaging quality and good detail resolution at both low and high frequencies.

[0111] Figure 6 The relative illumination curve of the optical lens 100 in this embodiment is shown, which represents the relative illumination value at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 95% at the maximum half-field angle, indicating that the optical lens has good relative illumination.

[0112] Example 2

[0113] Please see Figure 7 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The main difference between this embodiment and Embodiment 1 is that the object side surface S14 of the eighth lens L8 is convex near the optical axis; the image side surface S15 of the eighth lens L8 is concave near the optical axis; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0114] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0115] Table 2-1

[0116]

[0117] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0118] Table 2-2

[0119]

[0120] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 200 are respectively as follows: Figures 8 to 12 As shown.

[0121] from Figure 8 As can be seen, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 200 can correct distortion well.

[0122] from Figure 9 As can be seen, the axial aberration offset is controlled within -0.02mm to 0.04mm, indicating that the optical lens 200 can effectively correct axial aberration.

[0123] from Figure 10 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within -2μm to 4μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0124] from Figure 11 As can be seen, the MTF value of this embodiment is above 0.35 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and good detail resolution in both low and high frequency conditions.

[0125] from Figure 12 As can be seen, the relative illumination value of the optical lens is still greater than 85% at the maximum half field of view, indicating that the optical lens 200 has good relative illumination.

[0126] Example 3

[0127] Please see Figure 13 The diagram shows a schematic of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that: the sixth lens L6 and the seventh lens L7 form a cemented lens group with negative optical power; the object side S11 of the sixth lens L6 is concave; the image side of the sixth lens L6 is convex; the object side of the seventh lens L7 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0128] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0129] Table 3-1

[0130]

[0131] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0132] Table 3-2

[0133]

[0134] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 300 are respectively as follows: Figures 14 to 18 As shown.

[0135] from Figure 14As can be seen, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 300 can correct distortion well.

[0136] from Figure 15 As can be seen, the axial aberration offset is controlled within -0.02mm to 0.03mm, indicating that the optical lens 300 can correct axial aberration well.

[0137] from Figure 16 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within -1μm to 4μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0138] from Figure 17 As can be seen, the MTF value of this embodiment is above 0.4 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and good detail resolution in both low and high frequency conditions.

[0139] from Figure 18 As can be seen, the relative illumination value of the optical lens is still greater than 90% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0140] Example 4

[0141] Please see Figure 19 The diagram shows a schematic of the optical lens 400 provided in Embodiment 4 of the present invention. The main differences between this embodiment and Embodiment 1 are as follows: the sixth lens L6 and the seventh lens L7 form a cemented lens group with negative optical power; the object-side surface S11 of the sixth lens L6 is concave; the image-side surface of the sixth lens L6 is convex; the object-side surface of the seventh lens L7 is concave; the object-side surface S14 of the eighth lens L8 is convex near the optical axis; the image-side surface S15 of the eighth lens L8 is concave near the optical axis; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0142] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0143] Table 4-1

[0144]

[0145] The surface profile parameters of the aspherical lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0146] Table 4-2

[0147]

[0148] In this embodiment, the F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, MTF curve, and relative illumination diagram of the optical lens 400 are respectively as follows: Figures 20 to 24 As shown.

[0149] from Figure 20 As can be seen, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 400 can correct distortion well.

[0150] from Figure 21 As can be seen, the axial aberration offset is controlled within -0.06mm to 0.04mm, indicating that the optical lens 400 can correct axial aberration well.

[0151] from Figure 22 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within 0~4μm, indicating that the optical lens 400 can correct chromatic aberration well.

[0152] from Figure 23 As can be seen, the MTF value of this embodiment is above 0.55 throughout the entire field of view. The MTF curve decreases smoothly and evenly from the center to the edge of the field of view, demonstrating good imaging quality and good detail resolution in both low and high frequency conditions.

[0153] from Figure 24 As can be seen, the relative illumination value of the optical lens is still greater than 90% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0154] Please refer to Table 5 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value FNO, true image height IH corresponding to the maximum field of view, principal ray incident angle CRA at the maximum image height, maximum field of view FOV, and the values ​​corresponding to each conditional expression in each embodiment.

[0155] Table 5

[0156]

[0157] In summary, the optical lens provided by the present invention employs eight lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, giving the lens one or more advantages such as a large field of view, a large aperture, and high imaging quality.

[0158] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0159] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that, It sequentially comprises from the object side to the imaging surface along the optical axis: a first lens with negative refractive power, the object side surface of which is a convex surface and the image side surface of which is a concave surface; a second lens with negative refractive power, the object side surface of which is a concave surface and the image side surface of which is a concave surface; a third lens with positive refractive power, the object side surface of which is a convex surface and the image side surface of which is a concave surface; a fourth lens with negative refractive power, the object side surface of which is a convex surface and the image side surface of which is a concave surface; a fifth lens with positive refractive power, the object side surface of which is a convex surface and the image side surface of which is a convex surface; a sixth lens with negative refractive power; a seventh lens with positive refractive power, the image side surface of which is a convex surface; an eighth lens with negative refractive power; wherein, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -1<(R5-R6) / (R5+R6)<-0.4; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -0.9<(R3+R4) / (R3-R4)<0; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 2.5<TTL / IH<3.9; the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4<IH / EPD<5.5; the real image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2<IH / f<2.8; the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -9<f123 / f45678<-2.

2.

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: 6<TTL / f<8.5; the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view of the optical lens satisfy: 2.78<TTL / IH<3.58; the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: -0.98<(R5-R6) / (R5+R6)<-0.44; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: -0.88<(R3+R4) / (R3-R4)<-0.

01.

3. The optical lens according to claim 1, characterized in that, the maximum field of view FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 70°<FOV / FNO<85°; the real image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 4.32<IH / EPD<5.

14.

4. The optical lens according to claim 1, characterized in that, The true image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 2.15<IH / f<2.58; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.7<BFL / f<0.

9.

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: -3.3<f2 / f<-2.1, the effective focal length f of the optical lens and the curvature radius R3 of the object side surface of the second lens satisfy: -4.4<R3 / f<-2.4, the effective focal length f of the optical lens and the curvature radius R4 of the image side surface of the second lens satisfy: 3.5<R4 / f<40.

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: 1.7<f3 / f<3.3, the effective focal length f of the optical lens and the curvature radius R5 of the object side surface of the third lens satisfy: 1.1<R5 / f<1.5, the effective focal length f of the optical lens and the curvature radius R6 of the image side surface of the third lens satisfy: 3.2<R6 / f<85.

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: -1.9<f6 / f<-1.2, 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: 0<R11 / R12<10.

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: 1.15<f7 / f<3.6, the curvature radius R14 of the image side surface of the seventh lens and the effective focal length f of the optical lens satisfy: -3.7<R14 / f<-1.

2.

9. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -25<f8 / f<-4.2, the curvature radius R15 of the object side surface of the eighth lens and the curvature radius R16 of the image side surface of the eighth lens satisfy: 0<R16 / R15<400.

10. The optical lens according to claim 1, characterized in that, The combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f45678 of the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens satisfy: -8.35<f123 / f45678<-2.4; the clear aperture half-diameter d1 of the object side surface of the first lens and the clear aperture half-diameter d16 of the image side surface of the eighth lens satisfy: 1.6<d1 / d16<2.4.

Images