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 convex surface; a fourth lens with negative optical power, the object side of which is a concave surface near the optical axis 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, the object side of which is a convex surface and the image side of which is a concave surface; a seventh lens with positive optical power, the object side of which is a convex surface and 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 make the lens have 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 convex image-side surface.

[0010] The fourth lens with negative optical power has an object-side surface that is concave near the optical axis and an image-side surface that is concave.

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

[0012] The sixth lens with negative optical power has a convex object side and a concave image side.

[0013] The seventh lens with positive optical power has a convex object-side surface and a convex image-side surface.

[0014] The eighth lens with negative optical power has an object-side surface that is convex near the optical axis and an image-side surface that is concave near the optical axis.

[0015] where 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<(R3+R4) / (R3-R4)<0.6; and the radius of curvature R7 of the object-side surface of the fourth lens and the radius of curvature R8 of the image-side surface of the fourth lens satisfy: 0.4<(R7+R8) / (R7-R8)<1.

[0016] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6.5<TTL / f<8; and 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: 2.3<TTL / IH<3.3.

[0017] Further preferably, the maximum field of view FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 65°<FOV / FNO<85°; and 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: 4.5<IH / EPD<5.9.

[0018] Further preferably, 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: 2.2<IH / f<2.9; and 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] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -2<f1 / f<-1.5, the effective focal length f of the optical lens and the radius of curvature R1 of the object-side surface of the first lens satisfy: 2.6<R1 / f<5.5, and the effective focal length f of the optical lens and the radius of curvature R2 of the image-side surface of the first lens satisfy: 0.9<R2 / f<1.2.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3<f2 / f<-2, 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: -8<R3 / f<-3.8, 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: 2.4<R4 / f<4.4.

[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<1.3, 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: 1.6<R5 / f<2.3, 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: -1.3<R6 / f<-0.9.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -1.9<f4 / f<-1.3, 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: -50<R7 / f<-3.3, and 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: 1<R8 / f<1.5.

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -10<f8 / f<-5, the radius of curvature R15 of the object-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 15<R15 / f<24, and the radius of curvature R16 of the image-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 2.6<R16 / f<5.

[0024] Further preferably, the combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 3<f67 / f<6; 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: 0.1<f123 / f45678<0.4.

[0025] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with specific optical powers, and through specific surface shape matching and reasonable optical power distribution, can improve the imaging quality of the optical lens, reduce aberrations, enhance the imaging quality of the optical lens, and endow the lens with one or more advantages such as a large field of view, a large aperture, and high imaging quality. Brief Description of the Drawings

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 is a schematic structural diagram of an optical lens in Embodiment 1 of the present invention.

[0028] Figure 2 is an F-Tan(Theta) distortion curve diagram of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 3 is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 4 is a lateral chromatic aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 5 This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 6 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0033] Figure 7 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0034] Figure 8 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0035] Figure 9 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0036] Figure 10 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0037] Figure 11 This is the MTF curve of the optical lens in Embodiment 2 of the present invention.

[0038] Figure 12 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0039] Figure 13 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 14 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0041] Figure 15 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 16 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0043] Figure 17 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0044] Figure 18 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0045] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] It should be noted that the embodiments of the present application and the features in the embodiments may be combined with each other under the condition of no conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0053] The optical lens provided by the embodiment of the present invention consists of eight lenses, which are sequentially 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 along the optical axis from the object side to the imaging surface.

[0054] In some embodiments, the first lens may have negative refractive power, its object-side surface is convex, and its image-side surface is concave. The second lens may have negative refractive power, its object-side surface is concave, and its image-side surface is concave. The third lens may have positive refractive power, its object-side surface is convex, and its image-side surface is convex. The fourth lens may have negative refractive power, its object-side surface is concave near the optical axis, and its image-side surface is concave. The fifth lens may have positive refractive power, its object-side surface is convex, and its image-side surface is convex. The sixth lens may have negative refractive power, its object-side surface is convex, and its image-side surface is concave. The seventh lens may have positive refractive power, its object-side surface is convex, and its image-side surface is convex. The eighth lens may have negative refractive power, its object-side surface is convex near the optical axis, and its image-side surface is concave near the optical axis.

[0055] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the third lens and the fourth lens. It can be understood that the diaphragm can be used to limit the amount of incoming light to change the brightness of the formed image.

[0056] In some embodiments, the optical lens may further include an optical filter, and the optical filter may be disposed between the eighth lens and the imaging surface. The optical filter is used to filter out interfering light, so as to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0057] In some embodiments, the sixth lens and the seventh lens can be cemented 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 lowering the processing difficulty of the optical lens and increasing the assembly yield of the optical lens. In some embodiments, the combined focal length f67 of the sixth lens and the seventh lens and the focal length f of the optical lens satisfy: 3<f67 / f<6. Satisfying the above range can further correct the chromatic aberration of the optical lens and reduce the eccentricity sensitivity of the optical lens. More specifically, 3.22<f67 / f<5.65.

[0058] In some embodiments, 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<(R3+R4) / (R3-R4)<0.6; the radius of curvature R7 of the object-side surface of the fourth lens and the radius of curvature R8 of the image-side surface of the fourth lens satisfy: 0.4<(R7+R8) / (R7-R8)<1. Meeting the above ranges can correct the aberration of the optical lens, ensure that the light passing through the second lens and the fourth lens travels smoothly, reduce the tolerance sensitivity of the optical lens, and facilitate the smooth entry of light into the rear-end lens. More specifically, 0.11<(R3+R4) / (R3-R4)<0.49, 0.44<(R7+R8) / (R7-R8)<0.96.

[0059] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 6.5<TTL / f<8; 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: 2.3<TTL / IH<3.3. Meeting the above ranges, by reasonably controlling the total length, focal length and image height of the optical lens, it is helpful for the optical lens to achieve a balance between total length and volume, and is beneficial to improving the structural stability of the optical lens. More specifically, 6.83<TTL / f<7.56, 2.54<TTL / IH<2.99.

[0060] In some embodiments, the maximum field of view FOV of the optical lens and the F-number FNO of the optical lens satisfy: 65°<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: 4.5<IH / EPD<5.9. Meeting the above ranges helps to realize the characteristics of large field of view and large aperture of the optical lens, which is beneficial to increase the light throughput and improve the relative illumination. More specifically, 69°<FOV / FNO<81°, 5.05<IH / EPD<5.38.

[0061] In some embodiments, 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: 2.2<IH / f<2.9; 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. Meeting the above ranges can reasonably control the image height, focal length and back focal length of the optical lens. Under the condition of fixed focal length, the optical lens can be endowed with the characteristics of large target surface and long back focal length. The characteristic of large target surface helps the optical lens to improve imaging quality, and the characteristic of long back focal length can meet the arrangement requirement of the rear-end chip and reduce the difficulty of assembly and processing. More specifically, 2.52<IH / f<2.69, 0.74<BFL / f<0.85.

[0062] 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<-1.5, the effective focal length f of the optical lens and the curvature radius R1 of the object-side surface of the first lens satisfy: 2.6<R1 / f<5.5, and the effective focal length f of the optical lens and the curvature radius R2 of the image-side surface of the first lens satisfy: 0.9<R2 / f<1.2. Satisfying the above ranges enables the first lens to have appropriate negative optical power and surface profile, which helps collect light rays with a large field of view angle into the optical lens as much as possible to obtain more image information, and can control the trend of large-angle marginal light rays, so as to improve the imaging quality of the optical lens. More specifically, -1.84<f1 / f<-1.59, 2.84<R1 / f<4.93, 0.98<R2 / f<1.07.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3<f2 / f<-2, the effective focal length f of the optical lens and the curvature radius R3 of the object-side surface of the second lens satisfy: -8<R3 / f<-3.8, and the effective focal length f of the optical lens and the curvature radius R4 of the image-side surface of the second lens satisfy: 2.4<R4 / f<4.4. Satisfying the above ranges enables the second lens to have appropriate negative optical power and reasonable surface profile matching, which helps the divergent light rays smoothly enter each subsequent lens at the rear end, and keeps the light ray trend stable. More specifically, -2.83<f2 / f<-2.23, -7.75<R3 / f<-4.12, 2.68<R4 / f<4.04.

[0064] 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<1.3, the effective focal length f of the optical lens and the curvature radius R5 of the object-side surface of the third lens satisfy: 1.6<R5 / f<2.3, and the effective focal length f of the optical lens and the curvature radius R6 of the image-side surface of the third lens satisfy: -1.3<R6 / f<-0.9. Satisfying the above ranges enables the third lens to have appropriate positive optical power and surface profile, which facilitates light convergence, and the gentle lens shape is beneficial to volume reduction and cost lowering. More specifically, 1.08<f3 / f<1.18; 1.76<R5 / f<2.09; -1.21<R6 / f<-1.01.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -1.9<f4 / f<-1.3, 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: -50<R7 / f<-3.3, and 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: 1<R8 / f<1.5. Satisfying the above ranges, by reasonably controlling the focal length proportion and surface shape of the fourth lens, it is helpful to collect the light rays exiting through the front-end lenses, make the collected light rays smoothly enter the subsequent lenses, and is beneficial to improving the resolution capability of the optical lens. More specifically, -1.72<f4 / f<-1.43; -46.57<R7 / f<-3.6; 1.12<R8 / f<1.37.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f8 of the eighth lens satisfy: -10<f8 / f<-5, the radius of curvature R15 of the object-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 15<R15 / f<24, and the radius of curvature R16 of the image-side surface of the eighth lens and the effective focal length f of the optical lens satisfy: 2.6<R16 / f<5. Satisfying the above ranges, by reasonably controlling the focal length proportion and surface shape of the eighth lens, it helps to control the light rays to travel stably towards the image plane, obtain the characteristic of a large target surface, and enable the optical lens to ensure high resolution capability on the basis of eliminating ghost images, so as to improve the imaging quality of the optical lens. More specifically, -22.94<f8 / f<-4.66, 15.91<R15 / f<22.14, 2.84<R16 / f<4.63.

[0067] 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: 0.1<f123 / f45678<0.4. Satisfying the above range, by reasonably setting the focal length relationship of the lens groups before and after the aperture stop, 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, 0.14<f123 / f45678<0.33.

[0068] In some embodiments, the effective focal length f of the optical lens, the maximum field of view angle FOV and the real image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 50°<f×FOV / IH<65°. Satisfying the above range, by reasonably limiting the relationship among the focal length, field of view angle and image height of the optical lens, it is beneficial to realize the balance between the large field of view angle and large target surface imaging of the optical lens. More specifically, 52.13°<f×FOV / IH<60.45°.

[0069] In some embodiments, the clear aperture half-caliber d1 of the object side of the first lens, the real image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.25<d1 / (IH / 2) / tan(FOV / 2)<0.75. Satisfying the above range can make the front-end aperture small while ensuring the optical lens has a large field of view angle and a large image plane. More specifically, 0.28<d1 / (IH / 2) / tan(FOV / 2)<0.7.

[0070] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.6<f5 / f<2.2. Satisfying the above range, by reasonably controlling the focal length proportion of the fifth lens, it helps to smooth the light trend of the front-end lens, correct the aberration generated by the front-end lens, and improve the imaging quality. More specifically, 1.75<f5 / f<2.02.

[0071] 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<-1.4. Satisfying the above range, 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, -1.75<f6 / f<-1.53.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.1<f7 / f<1.4. Satisfying the above range, 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, 1.18<f7 / f<1.27.

[0073] 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: 1<f123 / f<1.6; 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: 4.3<f45678 / f<8. Satisfying the above range, by reasonably setting the focal lengths 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, 1.12<f123 / f<1.51; 4.74<f45678 / f<7.55.

[0074] In some embodiments, the optical lens satisfies the conditional expressions: 2.2mm<f<2.7mm, 1.1mm<EPD<1.3mm, 16mm<TTL<19mm, 1.8<FNO<2.2, 14°<CRA<20°, 1.8mm<BFL<2.1mm, 130°<FOV<170°, 6mm<IH<7mm; where f denotes the effective focal length of the optical lens, EPD denotes the entrance pupil diameter of the optical lens, TTL denotes the total optical length of the optical lens, FNO denotes the F-number of the optical lens, CRA denotes the chief ray incident angle at the maximum image height of the optical lens, BFL denotes the back focal length of the optical lens, FOV denotes the maximum field of view of the optical lens, and IH denotes 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 embodiments of the present invention at least has characteristics such as a large field of view, a large aperture, and high imaging quality. More specifically, 2.44mm<f<2.47mm, 1.21mm<EPD<1.24mm, 16.78mm<TTL<18.51mm, 1.9<FNO<2.1, 14.65°<CRA<19.63°, 1.83mm<BFL<2.07mm, 139°<FOV<161°, 6.19mm<IH<6.61mm.

[0075] In some embodiments, the material of the lenses in the optical lens provided by the present invention may be glass or plastic. When the material of the lens is plastic, the production cost can be effectively reduced. In addition, when the material of the lens is glass, the geometric chromatic aberration of the optical system can be effectively corrected by utilizing the low dispersion characteristic of glass itself. 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.

[0076] 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 the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the third lens, the fourth lens, the fifth lens and the eighth lens of the present invention are aspherical lenses, and the first lens, the second lens, the sixth lens and the seventh lens are spherical lenses.

[0077] In various embodiments of the present invention, when the lenses are aspherical lenses, the shape of each aspherical surface of the optical lens satisfies the following equation:

[0078]

[0079] 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.

[0080] 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.

[0081] Example 1

[0082] 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.

[0083] Among them, the first lens L1 has negative optical power, its object side S1 is convex, and its image side S2 is concave.

[0084] The second lens L2 has negative optical power, its object side S3 is concave, and its image side S4 is concave.

[0085] The third lens L3 has positive optical power, its object side S5 is convex, and its image side S6 is convex.

[0086] The fourth lens L4 has negative optical power, its object side S7 is concave near the optical axis, and its image side S8 is concave.

[0087] The fifth lens L5 has positive optical power, its object side S9 is convex, and its image side S10 is convex.

[0088] The sixth lens L6 has negative optical power, its object side S11 is convex, and its image side is concave.

[0089] The seventh lens L7 has positive optical power, its object side is convex, and its image side S13 is convex.

[0090] 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.

[0091] The eighth lens L8 has negative optical power. Its object side S14 is convex near the optical axis, and its image side S15 is concave near the optical axis.

[0092] The object-side surface S16 and the image-side surface S17 of filter G1 are both planar.

[0093] The imaging plane S18 is a plane.

[0094] 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.

[0095] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0096] Table 1-1

[0097]

[0098]

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

[0100] Table 1-2

[0101] S5 1.24E+00 -1.03E-03 1.03E-03 9.60E-04 -8.44E-04 4.03E-04 -1.00E-04 1.33E-05 S6 -1.47E+01 -5.91E-03 9.43E-03 -8.24E-03 5.38E-03 -2.17E-03 4.69E-04 -3.72E-05 S7 -4.10E+02 1.81E-02 -1.60E-02 4.00E-03 -4.59E-04 -3.64E-04 1.48E-04 -1.85E-05 S8 -1.07E+01 -6.72E-03 2.08E-03 -3.62E-04 -7.30E-05 1.50E-05 2.98E-06 -8.57E-07 S9 -5.58E+01 -6.85E-03 1.37E-03 1.59E-04 -4.24E-06 -1.16E-05 0.00E+00 0.00E+00 S10 -3.98E-01 -5.29E-03 5.17E-05 -2.67E-05 -4.67E-05 1.23E-05 0.00E+00 0.00E+00 S14 -3.32E+39 -1.68E-02 8.83E-05 -3.82E-05 -3.49E-06 -1.60E-06 -1.54E-07 1.73E-08 S15 -2.58E+01 -1.42E-02 2.21E-04 -6.19E-06 -4.59E-06 -2.48E-07 7.82E-08 -4.49E-09

[0102] Figure 2 The F-Tan (Theta) distortion curve of the optical lens 100 in this embodiment is shown, which 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 figure, the distortion value changes relatively smoothly as the field of view increases, indicating that the optical lens 100 can correct distortion well.

[0103] 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 -0.02 mm to 0.02 mm, indicating that the optical lens 100 can correct axial aberration well.

[0104] Figure 4The 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 0–3 μm, indicating that the optical lens 100 can effectively correct chromatic aberration.

[0105] 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.

[0106] 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-of-view 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 70% at the maximum half-field-of-view angle, indicating that the optical lens has good relative illumination.

[0107] Example 2

[0108] Please see Figure 7 The figure shown is 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 optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

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

[0110] Table 2-1

[0111]

[0112]

[0113] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0114] Table 2-2

[0115] S5 1.24E+00 -1.03E-03 1.03E-03 9.60E-04 -8.44E-04 4.03E-04 -1.00E-04 1.33E-05 S6 -1.47E+01 -5.91E-03 9.43E-03 -8.24E-03 5.38E-03 -2.17E-03 4.69E-04 -3.72E-05 S7 -4.10E+02 1.81E-02 -1.60E-02 4.00E-03 -4.59E-04 -3.64E-04 1.48E-04 -1.85E-05 S8 -1.07E+01 -6.72E-03 2.08E-03 -3.62E-04 -7.30E-05 1.50E-05 2.98E-06 -8.57E-07 S9 -5.58E+01 -6.85E-03 1.37E-03 1.59E-04 -4.24E-06 -1.16E-05 0.00E+00 0.00E+00 S10 -3.98E-01 -5.29E-03 5.17E-05 -2.67E-05 -4.67E-05 1.23E-05 0.00E+00 0.00E+00 S14 -3.32E+39 -1.68E-02 8.83E-05 -3.82E-05 -3.49E-06 -1.60E-06 -1.54E-07 1.73E-08 S15 -2.58E+01 -1.42E-02 2.21E-04 -6.19E-06 -4.59E-06 -2.48E-07 7.82E-08 -4.49E-09

[0116] 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.

[0117] 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.

[0118] 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.

[0119] from Figure 10 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within 0 to 3 μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0120] from Figure 11 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.

[0121] from Figure 12 As can be seen, the relative illumination value of the optical lens is still greater than 75% at the maximum half field of view, indicating that the optical lens 200 has good relative illumination.

[0122] Example 3

[0123] Please see Figure 13 The figure shown is a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. The main difference between this embodiment and Embodiment 1 is that the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0124] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0125] Table 3-1

[0126]

[0127] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0128] Table 3-2

[0129]

[0130]

[0131] 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.

[0132] from Figure 14 As 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.

[0133] from Figure 15 As can be seen, the axial aberration offset is controlled within -0.08mm to 0.04mm, indicating that the optical lens 300 can correct axial aberration well.

[0134] from Figure 16 As can be seen, the transverse 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.

[0135] from Figure 17 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.

[0136] from Figure 18 As can be seen, the relative illumination value of the optical lens is still greater than 68% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0137] Please refer to Table 4 for the optical characteristics corresponding to each of the above embodiments, including the effective focal length f, total optical length TTL, aperture value FNO, true image height IH corresponding to the maximum field of view, principal ray incident angle CRA at the maximum image height, maximum field of view FOV, and the values ​​corresponding to each conditional expression in each embodiment.

[0138] Table 4

[0139]

[0140]

[0141] 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.

[0142] 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.

[0143] 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, Sequentially along the optical axis from the object side to the image plane, the system comprises: a first lens with negative optical power, of which the object side is convex and the image side is concave; a second lens with negative optical power, of which the object side is concave and the image side is concave; a third lens with positive optical power, of which the object side is convex and the image side is convex; a fourth lens with negative optical power, of which the object side is concave at the position near the optical axis and the image side is concave; a fifth lens with positive optical power, of which the object side is convex and the image side is convex; a sixth lens with negative optical power, of which the object side is convex and the image side is concave; a seventh lens with positive optical power, of which the object side is convex and the image side is convex; an eighth lens with negative optical power, of which the object side is convex at the position near the optical axis and the image side is concave at the position near the optical axis; wherein the radius of curvature R3 of the object side of the second lens and the radius of curvature R4 of the image side of the second lens satisfy: 0<(R3+R4) / (R3-R4)<0.6; the radius of curvature R7 of the object side of the fourth lens and the radius of curvature R8 of the image side of the fourth lens satisfy: 0.4<(R7+R8) / (R7-R8)<1; 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: 2.3<TTL / IH<3.3; 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: 4.5<IH / EPD<5.

9.

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: 6.5<TTL / f<8; 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: 2.54<TTL / IH<2.

99.

3. The optical lens according to claim 1, characterized in that, The maximum field of view FOV of the optical lens and the f-number FNO of the optical lens satisfy: 65°<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: 5.05<IH / EPD<5.

38.

4. The optical lens according to claim 1, characterized in 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: 2.2<IH / f<2.9; 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 f1 of the first lens satisfy: -2<f1 / f<-1.5, the effective focal length f of the optical lens and the radius of curvature R1 of the object side of the first lens satisfy: 2.6<R1 / f<5.5, and the effective focal length f of the optical lens and the radius of curvature R2 of the image side of the first lens satisfy: 0.9<R2 / f<1.

2.

6. 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<f2 / f<-2, the effective focal length f of the optical lens and the object-side curvature radius R3 of the second lens satisfy: -8<R3 / f<-3.8, and the effective focal length f of the optical lens and the image-side curvature radius R4 of the second lens satisfy: 2.4<R4 / f<4.

4.

7. 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<1.3, the effective focal length f of the optical lens and the object-side curvature radius R5 of the third lens satisfy: 1.6<R5 / f<2.3, and the effective focal length f of the optical lens and the image-side curvature radius R6 of the third lens satisfy: -1.3<R6 / f<-0.

9.

8. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -1.9<f4 / f<-1.3, the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: -50<R7 / f<-3.3, and the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: 1<R8 / f<1.

5.

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: -10<f8 / f<-5, the object-side curvature radius R15 of the eighth lens and the effective focal length f of the optical lens satisfy: 15<R15 / f<24, and the image-side curvature radius R16 of the eighth lens and the effective focal length f of the optical lens satisfy: 2.6<R16 / f<5.

10. The optical lens according to claim 1, characterized in that, The combined focal length f67 of the sixth lens and the seventh lens and the effective focal length f of the optical lens satisfy: 3<f67 / f<6; 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: 0.1<f123 / f45678<0.4.

Images