Optical lens

Abstract

The application provides an optical lens which is composed of six lenses and sequentially includes, along an optical axis from an object side to an imaging surface, a first lens with negative optical power, the object side surface of which is a concave surface and the image side surface of which is a concave surface; a second lens with positive optical power, the object side surface of which is a convex surface and the image side surface of which is a convex surface; a third lens with positive optical power, the object side surface of which is a convex surface and the image side surface of which is a convex surface; a fourth lens with positive optical power, the object side surface of which is a convex surface; a fifth lens with negative optical power, the image side surface of which is a concave surface; and a sixth lens with negative optical power, the object side surface of which is a convex surface and the image side surface of which is a concave surface; wherein a real image height IH corresponding to a maximum field angle of the optical lens and an entrance pupil diameter EPD of the optical lens satisfy 11<IH / EPD<14. The optical lens provided by the application can improve the imaging quality of the optical lens, reduce aberration and improve the imaging quality of the optical lens through specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

[0015] ,

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

[0002] Law enforcement recorders are mainly used for digitally recording the on-site situation during law enforcement, such as video recording, photographing, audio recording, etc., so as to provide effective on-site image materials afterwards. During on-site law enforcement, law enforcement officers need to record a large range and clear images. However, the lenses of law enforcement recorders on the market either record images unclearly or have too small a field of view and cannot record too many pictures.

[0003] Therefore, how to make the lens of a law enforcement recorder meet high imaging quality is an urgent problem to be solved at present. Summary of the Invention

[0004] In view of the above problems, the object of the present invention is to provide an optical lens, which has the advantage of excellent imaging quality.

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

[0006] An optical lens is composed of six lenses, and successively includes along the optical axis from the object side to the imaging surface:

[0007] A first lens with negative optical power, whose object side is concave and whose image side is concave;

[0008] A second lens with positive optical power, whose object side is convex and whose image side is convex;

[0009] A third lens with positive optical power, whose object side is convex and whose image side is convex;

[0010] A fourth lens with positive optical power, whose object side is convex;

[0011] A fifth lens with negative optical power, whose image side is concave;

[0012] A sixth lens with negative optical power, whose object side is convex and whose image side is concave;

[0013] Wherein, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 11 < IH / EPD < 14.

[0014] Further preferably, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.7 < TTL / f < 2; the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.3 < TTL / IH < 1.6.

[0015] Further preferably, the maximum field of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 10° < FOV / Fno < 11°; the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 72° < (f × FOV) / IH < 79°.

[0016] Further preferably, 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: 1.2 < IH / f < 1.5; the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.3 < BFL / f < 0.4.

[0017] Further preferably, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis satisfy: 0.75 < ∑CT / TTL < 0.9; the half-aperture d1 of the object side surface of the first lens, the FOV of the maximum field of view of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 0.4 < d1 / (IH / 2) / Tan(FOV / 2) < 0.7; the half-aperture d1 of the object side surface of the first lens and the half-aperture d12 of the image side surface of the sixth lens satisfy: 0.5 < d1 / d12 < 0.8.

[0018] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.7 < f3 / f < 16; the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.2 < f4 / f < 2.4.

[0019] Further preferably, the combined focal length f123 of the first lens, the second lens, and the third lens and the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens satisfy: -0.6 < f123 / f456 < -0.1; the combined focal length f12 of the first lens and the second lens and the combined focal length f123 of the first lens, the second lens, and the third lens satisfy: 1 < f12 / f123 < 1.5.

[0020] Further preferably, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0 < f2 / f3 < 0.4; the effective focal length f of the optical lens and the image side curvature radius R4 of the second lens satisfy: -1.3 < R4 / f < -0.7; the effective focal length f of the optical lens and the object side curvature radius R5 of the third lens satisfy: 6 < R5 / f < 28.

[0021] More preferably, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -1.4 < f4 / f5 < -0.9; the central thickness CT5 of the fifth lens, the image-side curvature radius R8 of the fourth lens, and the object-side curvature radius R9 of the fifth lens satisfy: 0.9 < (R8 + CT5) / R9 < 1.1.

[0022] More preferably, the effective focal length f of the optical lens and the object-side curvature radius R1 of the first lens satisfy: -24 < R1 / f < -18; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 0.7 < (R1 + R2) / (R1 - R2) < 1.

[0023] More preferably, the object-side curvature radius R3 of the second lens and the image-side curvature radius R4 of the second lens satisfy: 0 < (R3 + R4) / (R3 - R4) < 0.5; the image-side curvature radius R10 of the fifth lens and the object-side curvature radius R11 of the sixth lens satisfy: 1.9 < (R10 + R11) / (R10 - R11) < 2.8.

[0024] Compared with the prior art, the optical lens provided by the present invention adopts six lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the imaging quality of the optical lens, reduce aberrations, improve the imaging quality of the optical lens, and make the lens have one or more advantages such as miniaturization, large field angle, small aperture, and large depth of field. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, where:

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

[0027] Figure 2 is a field curvature curve graph of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 is an F-Tan(Theta) distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0029] Figure 4 is an axial aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 5 is a lateral chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 6This is an MTF curve of the optical lens in Embodiment 1 of the present invention.

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

[0033] Figure 8 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0034] Figure 9 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

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

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

[0037] Figure 12 This is the MTF 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 a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 15 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

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

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

[0043] Figure 18 This is an MTF curve of the optical lens in Embodiment 3 of the present invention.

[0044] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] The optical lens provided by the embodiment of the present invention is composed of six lenses, which are, in sequence from the object side to the imaging surface along the optical axis, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens.

[0053] In some embodiments, the first lens may have a negative optical power, its object side surface is concave, and its image side surface is concave. The second lens may have a positive optical power, its object side surface is convex, and its image side surface is convex. The third lens may have a positive optical power, its object side surface is convex, and its image side surface is convex. The fourth lens may have a positive optical power, its object side surface is convex, and its image side surface may be concave or convex. The fifth lens may have a negative optical power, its object side surface may be concave or convex, and its image side surface is concave. The sixth lens may have a negative optical power, its object side surface is convex, and its image side surface is concave.

[0054] In some embodiments, the image side surface of the fourth lens is convex, and the object side surface of the fifth lens is concave; or the image side surface of the fourth lens is concave, and the object side surface of the fifth lens is convex.

[0055] In some embodiments, the optical lens may further include an aperture stop, and the aperture stop may be located between the first lens and the object side. It can be understood that the aperture stop is used to limit the amount of incident light to change the brightness of the imaging.

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

[0057] In some embodiments, the first lens and the second lens may be glued together to form a cemented lens, and the fourth lens and the fifth lens may be glued together to form a cemented lens; it can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0058] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 11 < IH / EPD < 14. Meeting the above range makes all the subjects clearly visible on the screen, realizes high-definition imaging of the photographed object within a specific distance, and enables accurate image acquisition when the image moves within a relatively long range. More specifically, 11.78 < IH / EPD < 13.69.

[0059] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.7 < TTL / f < 2. Meeting the above range can effectively limit the length of the lens, which is conducive to the miniaturization of the optical lens. More specifically, 1.93 < TTL / f < 1.98.

[0060] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of view of the optical lens satisfy: 1.3 < TTL / IH < 1.6. Meeting the above range ensures that, with the same total length of the lens, it has a larger image plane, can match a larger-sized imaging chip to achieve high-definition imaging, and better realizes the balance between the small total length and the large image plane of the lens. More specifically, 1.38 < TTL / IH < 1.56.

[0061] In some embodiments, the maximum field angle of view FOV of the optical lens and the f-number Fno of the optical lens satisfy: 10° < FOV / Fno < 11°. Meeting the above range limits the optical lens to have an appropriate field angle of view and f-number, can collect light at a large angle, and obtain good imaging quality. More specifically, 10.3° < FOV / Fno < 10.82°.

[0062] In some embodiments, the effective focal length f of the optical lens, the maximum field angle of view FOV of the optical lens, and the true image height IH corresponding to the maximum field angle of view of the optical lens satisfy: 72° < (f × FOV) / IH < 79°. Meeting the above range can ensure that the optical lens has the characteristics of a large field of view and a large image plane by reasonably restricting the relationship between the focal length, field angle of view, and image height of the optical lens, so that the optical lens has good optical performance and can well capture the details of the photographed object. More specifically, 72.81° < (f × FOV) / IH < 78.72°.

[0063] In some embodiments, the true image height IH corresponding to the maximum field angle of view of the optical lens and the effective focal length f of the optical lens satisfy: 1.2 < IH / f < 1.5. Meeting the above range controls the image height and focal length of the optical lens within a reasonable range, which helps the optical lens to have the characteristic of a large image plane and improve the imaging quality. More specifically, 1.26 < IH / f < 1.41.

[0064] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.3 < BFL / f < 0.4. Meeting the above range limits the optical lens to have an appropriate back focus, which is convenient for reasonably arranging the positions of each lens and reduces the processing and assembly difficulty. More specifically, 0.32 < BFL / f < 0.38.

[0065] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis satisfy: 0.75 < ∑CT / TTL < 0.9. Meeting the above range can effectively compress the total length of the optical lens and is conducive to the structural design and production process of the optical lens. More specifically, 0.78 < ∑CT / TTL < 0.82.

[0066] In some embodiments, the clear aperture semi-diameter d1 of the object side surface of the first lens, the FOV of the maximum field angle of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.4 < d1 / (IH / 2) / Tan(FOV / 2) < 0.7. Meeting the above range can ensure the balance between the small front aperture, large field angle, and large image plane of the optical lens, which is conducive to the miniaturization of the optical lens. More specifically, 0.49 < d1 / (IH / 2) / Tan(FOV / 2) < 0.67.

[0067] In some embodiments, the clear aperture semi-diameter d1 of the object side surface of the first lens and the clear aperture semi-diameter d12 of the image side surface of the sixth lens satisfy: 0.5 < d1 / d12 < 0.8. Meeting the above range can reasonably match the aperture ratios of the first lens and the sixth lens, facilitating structural design and at the same time helping to improve the imaging quality of the optical lens. More specifically,

[0068] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 3.7 < f3 / f < 16. Meeting the above range, setting the third lens to have positive refractive power is conducive to converging light while correcting the field curvature and distortion of the optical lens and improving the imaging quality of the optical lens. More specifically, 3.71 < f3 / f < 15.09.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.2 < f4 / f < 2.4. Meeting the above range can effectively further converge light, reduce the difficulty of correcting the edge field distortion, and improve the overall imaging quality. More specifically, 1.22 < f4 / f < 2.35.

[0070] In some embodiments, the combined focal length f123 of the first lens, the second lens, and the third lens and the combined focal length f456 of the fourth lens, the fifth lens, and the sixth lens satisfy: -0.6 < f123 / f456 < -0.1. Meeting the above range, through the reasonably set lens group relationship, it is conducive to balancing various aberrations of the system and improving the overall imaging quality. More specifically, -0.59 < f123 / f456 < -0.17.

[0071] In some embodiments, the combined focal length f12 of the first lens and the second lens and the combined focal length f123 of the first lens, the second lens, and the third lens satisfy: 1 < f12 / f123 < 1.5. Meeting the above range, the first lens and the second lens form a cemented lens group with positive optical power; it can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, and can also balance the aberration of the optical lens, improving the imaging quality of the optical lens.

[0072] In some embodiments, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0 < f2 / f3 < 0.4; the effective focal length f of the optical lens and the image-side curvature radius R4 of the second lens satisfy: -1.3 < R4 / f < -0.7; the effective focal length f of the optical lens and the object-side curvature radius R5 of the third lens satisfy: 6 < R5 / f < 28. Meeting the above range can reduce the light deflection angle and make the light path more stable; at the same time, it can correct coma and field curvature, improve the flatness of imaging, and enhance the imaging quality of the optical lens. More specifically, 0.03 < f2 / f3 < 0.34; -1.23 < R4 / f < -0.77; 6.7 < R5 / f < 27.42.

[0073] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -1.4 < f4 / f5 < -0.9. Meeting the above range, by reasonably setting the focal length relationship of the cemented lens, on the one hand, it can effectively correct the chromatic aberration of the system, improve the imaging quality, and at the same time can effectively improve the image quality of the optical system, reduce the light energy loss, and increase the imaging clarity. More specifically, -1.4 < f4 / f5 < -0.9.

[0074] In some embodiments, the central thickness CT5 of the fifth lens, the image-side curvature radius R8 of the fourth lens, and the object-side curvature radius R9 of the fifth lens satisfy: 0.9 < (R8 + CT5) / R9 < 1.1. Meeting the above range, reasonably controlling the shapes of the image side of the fourth lens and the object side of the fifth lens and the thickness of the fifth lens helps to reduce the difficulty of correcting the marginal field distortion. More specifically, 0.9 < (R8 + CT5) / R9 < 1.1.

[0075] In some embodiments, 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: -24 < R1 / f < -18; the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 0.7 < (R1 + R2) / (R1 - R2) < 1. Satisfying the above ranges can effectively control the surface shape of the first lens, which is beneficial to increasing the field angle, and at the same time control the front aperture of the optical lens, achieving a balance between a large field angle and miniaturization. More specifically, -23.34 < R1 / f < -18.43; 0.73 < (R1 + R2) / (R1 - R2) < 0.92.

[0076] 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) < 0.5. Satisfying the above range can effectively reduce the degree of light deflection when entering the second lens, which is beneficial to maintaining the miniaturization of the lens head. More specifically, 0.05 < (R3 + R4) / (R3 - R4) < 0.47.

[0077] In some embodiments, the radius of curvature R10 of the image side surface of the fifth lens and the radius of curvature R11 of the object side surface of the sixth lens satisfy: 1.9 < (R10 + R11) / (R10 - R11) < 2.8. Satisfying the above range can effectively reduce the degree of light deflection when entering the sixth lens, effectively improve the field curvature and aberration, and improve the imaging quality of the optical lens. More specifically, 1.96 < (R10 + R11) / (R10 - R11) < 2.75.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -3.2 < f1 / f < -0.9. Satisfying the above range, by setting the first lens to have a negative refractive power, it is beneficial for the first lens to collect light at a larger angle and collect as much light as possible to enter the rear optical system, achieving a large field angle while increasing the light flux. More specifically, -3.15 < f1 / f < -0.93.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 0.6 < f / f < 1.3. Satisfying the above range can effectively converge light, ensure that the lens reduces the difficulty of correcting the edge field distortion while achieving a large field angle, and improve the overall imaging quality. More specifically, 0.61 < f2 / f < 1.23.

[0080] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -1.8 < f5 / f < -1.1; the effective focal length f of the optical lens and the image-side curvature radius R10 of the fifth lens satisfy: 1.2 < R10 / f < 3.7. By satisfying the above conditions, the spherical aberration introduced by the front-end optical system can be effectively compensated by reasonably controlling the focal length and the image-side surface shape of the fifth lens, and the overall imaging quality can be improved. More specifically, -1.76 < f5 / f < -1.18; 1.22 < R10 / f < 3.65.

[0081] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -3 < f6 / f < -2. By satisfying the above range, various aberrations generated by the front lens group can be effectively balanced. At the same time, it is beneficial to increase the divergence degree of light, increase the area of light entering the imaging surface, achieve large-format imaging of the lens, and improve the imaging quality of the optical lens. More specifically, -2.91 < f6 / f < -2.11.

[0082] In some embodiments, the object-side clear aperture radius d1 of the first lens and the central thickness CT1 of the first lens satisfy: 2.3 < d1 / CT1 < 4.6. By satisfying the above range, on the premise of ensuring the processability of the first lens, the optical lens can have a more compact structure, which is beneficial to achieving miniaturization. More specifically, 2.37 < d1 / CT1 < 4.52.

[0083] In some embodiments, the image-side clear aperture sag Sag12 of the sixth lens and the image-side clear aperture radius d12 of the sixth lens satisfy: 0.1 < Sag12 / d12 < 0.2. By satisfying the above range, it helps to control the trend of marginal field light and highlight the detail information of the central field of the optical lens. More specifically, 0.12 < Sag12 / d12 < 0.2.

[0084] In some embodiments, the optical lens satisfies the conditional formula: 4.6 mm < f < 4.9 mm, 0.4 mm < EPD < 0.6 mm, 9.1 mm < TTL < 9.5 mm, 9.3 < Fno < 9.9, 18° < CRA < 22°, 1.5 mm < BFL < 1.8 mm, 90° < FOV < 115°, 5.3 mm < IH < 7.5 mm; where f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, CRA represents the chief ray angle of incidence at the maximum image height of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field angle of the optical lens, and IH represents the true image height corresponding to the maximum field angle of the optical lens. Meeting the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least the characteristics of miniaturization, small aperture, large depth of field, large field angle, etc. More specifically, 4.63 mm < f < 4.89 mm, 0.49 mm < EPD < 0.51 mm, 9.14 mm < TTL < 9.5 mm, 9.35 < Fno < 9.81, 18.59° < CRA < 21.01, 1.58 mm < BFL < 1.75 mm, 99° < FOV < 107°, 5.89 mm < IH < 6.85 mm.

[0085] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. All the lenses in the optical lens provided by the present invention are glass lenses.

[0086] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens can adopt 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 sixth lens of the present invention adopts an aspherical lens, and the first lens, the second lens, the third lens, the fourth lens, and the fifth lens can all adopt spherical lenses.

[0087] In each embodiment of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0088]

[0089] 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.

[0090] 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.

[0091] Example 1

[0092] 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: aperture ST, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, and filter G1.

[0093] Among them, the first lens L1 has negative optical power, its object side S1 is concave, and its image side S2 is concave.

[0094] The second lens L2 has positive optical power, its object side S2 is convex, and its image side S3 is convex.

[0095] The first lens L1 and the second lens L2 form a cemented lens group with positive optical power, that is, the cemented surface of the image side of the first lens L1 and the object side of the second lens L2 is S2.

[0096] The third lens L3 has positive optical power, its object side S4 is convex, and its image side S5 is convex.

[0097] The fourth lens L4 has positive optical power, its object side S6 is convex, and its image side S7 is convex.

[0098] The fifth lens L5 has negative optical power, its object side S7 is concave, and its image side S8 is concave.

[0099] The fourth lens L4 and the fifth lens L5 form a cemented lens group with positive optical power, that is, the cemented surface of the image side of the fourth lens L4 and the object side of the fifth lens L5 is S7.

[0100] The sixth lens L6 has negative optical power, its object side S9 is convex, and its image side S10 is concave.

[0101] The object-side surface S11 and the image-side surface S12 of the filter G1 are both planar.

[0102] The imaging plane S13 is a plane.

[0103] The sixth lens L6 is a glass aspherical lens, while the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are all glass spherical lenses.

[0104] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0105] Table 1-1

[0106]

[0107] The surface profile parameters of the aspherical lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0108] Table 1-2

[0109]

[0110] Figure 2 The field curvature curve of the optical lens 100 in this embodiment is shown, which represents the degree of curvature of light in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within ±0.4 mm, indicating that the optical lens 100 can correct the field curvature well.

[0111] Figure 3 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 is controlled within -50% to 0, indicating that the optical lens 100 can correct distortion well.

[0112] Figure 4 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 to 0.04 mm, indicating that the optical lens 100 can correct axial aberration well.

[0113] Figure 5The 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 (0.546 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 figure, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±4 μm, indicating that the optical lens 100 can effectively correct chromatic aberration.

[0114] Figure 6 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 0.3 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.

[0115] Example 2

[0116] Please see Figure 7 The diagram shown is a structural schematic of the optical lens 200 provided in Embodiment 2 of the present invention. This embodiment is similar to...

[0117] Compared to Example 1, the main difference lies in the fact that the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0118] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0119] Table 2-1

[0120]

[0121]

[0122] The surface profile parameters of the aspherical lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0123] Table 2-2

[0124] Face number K B C D E F G H S9 -5.76E+01 4.44E-03 -2.40E-03 3.67E-04 -2.20E-05 4.99E-07 -2.15E-09 6.02E-11 S10 -4.62E+00 4.84E-04 -1.47E-03 1.42E-04 -4.18E-06 -3.24E-08 1.32E-09 8.87E-11

[0125] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 200 are respectively as follows: Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 As shown.

[0126] from Figure 8 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.4mm, indicating that the optical lens 200 can effectively correct the field curvature.

[0127] from Figure 9 As can be seen, the distortion value is controlled within -50% to 0, indicating that the optical lens 200 can correct distortion well.

[0128] from Figure 10 As can be seen, the axial aberration offset is controlled within ±0.03mm, indicating that the optical lens 200 can correct axial aberration well.

[0129] from Figure 11 As can be seen, the chromatic aberration of the longest and shortest wavelengths is controlled within ±4μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0130] from Figure 12 As can be seen, the MTF value of this embodiment is above 0.3 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.

[0131] Example 3

[0132] Please see Figure 13 The figure shows 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 image side of the fourth lens L4 is concave, the object side of the fifth lens L5 is convex, and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0133] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0134] Table 3-1

[0135]

[0136] The surface profile parameters of the aspherical lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0137] Table 3-2

[0138]

[0139] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, and MTF curve of the optical lens 300 are respectively as follows: Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 As shown.

[0140] from Figure 14 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.2mm, indicating that the optical lens 300 can effectively correct field curvature.

[0141] from Figure 15 As can be seen, the distortion value is controlled within -50% to 0, indicating that the optical lens 300 can correct distortion well.

[0142] from Figure 16 As can be seen, the axial aberration offset is controlled within 0 to 0.03 mm, indicating that the optical lens 300 can correct axial aberration well.

[0143] from Figure 17 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±2μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0144] from Figure 18 As can be seen, the MTF value of this embodiment is above 0.45 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.

[0145] 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.

[0146] Table 4

[0147]

[0148]

[0149] In summary, the optical lens provided by the present invention uses six 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 miniaturization, large field of view, small aperture, and large depth of field.

[0150] 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.

[0151] 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 six lenses, characterized in that, It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with a negative optical power, whose object side is concave and whose image side is concave; A second lens with a positive optical power, whose object side is convex and whose image side is convex; A third lens with a positive optical power, whose object side is convex and whose image side is convex; A fourth lens with a positive optical power, whose object side is convex; A fifth lens with a negative optical power, whose image side is concave; A sixth lens with a negative optical power, whose object side is convex and whose image side is concave; Wherein, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 11 < IH / EPD < 14; The total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 1.3 < TTL / IH < 1.

6.

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: 1.7 < TTL / f < 2.

3. The optical lens according to claim 1, characterized in that, The maximum field angle FOV of the optical lens and the f-number Fno of the optical lens satisfy: 10° < FOV / Fno < 11°; The effective focal length f of the optical lens, the maximum field angle FOV of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 72° < (f × FOV) / IH < 79°.

4. The optical lens according to claim 1, characterized in that, The true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.2 < IH / f < 1.5; The back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.3 < BFL / f < 0.

4.

5. The optical lens according to claim 1, characterized in that, The total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the sixth lens along the optical axis respectively satisfy: 0.75 < ∑CT / TTL < 0.9; The clear aperture semi-diameter d1 of the object side of the first lens, the FOV of the maximum field angle of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 0.4 < d1 / (IH / 2) / Tan(FOV / 2) < 0.7; The clear aperture semi-diameter d1 of the object side of the first lens and the clear aperture semi-diameter d12 of the image side of the sixth lens satisfy: 0.5 < d1 / d12 < 0.

8.

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: 3.7 < f3 / f < 16; The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.2 < f4 / f < 2.

4.

7. 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 f456 of the fourth lens, the fifth lens and the sixth lens satisfy: -0.6 < f123 / f456 < -0.1; The combined focal length f12 of the first lens and the second lens and the combined focal length f123 of the first lens, the second lens and the third lens satisfy: 1 < f12 / f123 < 1.

5.

8. The optical lens according to claim 1, characterized in that, The focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 0 < f2 / f3 < 0.4; the effective focal length f of the optical lens and the image-side curvature radius R4 of the second lens satisfy: -1.3 < R4 / f < -0.7; the effective focal length f of the optical lens and the object-side curvature radius R5 of the third lens satisfy: 6 < R5 / f < 28.

9. The optical lens according to claim 1, characterized in that, The focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: -1.4 < f4 / f5 < -0.9; the central thickness CT5 of the fifth lens, the image-side curvature radius R8 of the fourth lens and the object-side curvature radius R9 of the fifth lens satisfy: 0.9 < (R8 + CT5) / R9 < 1.

1.

10. The optical lens according to claim 1, characterized in that, The effective focal length f of the optical lens and the object-side curvature radius R1 of the first lens satisfy: -24 < R1 / f < -18; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: 0.7 < (R1 + R2) / (R1 - R2) < 1.

11. The optical lens according to claim 1, characterized in that, The object-side curvature radius R3 of the second lens and the image-side curvature radius R4 of the second lens satisfy: 0 < (R3 + R4) / (R3 - R4) < 0.5; the image-side curvature radius R10 of the fifth lens and the object-side curvature radius R11 of the sixth lens satisfy: 1.9 < (R10 + R11) / (R10 - R11) < 2.8.

Images