Optical lens

Abstract

The invention provides an optical lens, which is composed of six lenses and sequentially comprises a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an image side along an optical axis, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the fourth lens has positive focal power, and the object side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, and the image side surface of the fifth lens is a concave surface; the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a concave surface; wherein the real image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens meet the following conditions: 11lt; iH / EPDlt; 14. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved.

Description

Technical Field

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

[0002] Law enforcement cameras are mainly used for digitally recording the on-site situation during law enforcement, such as video recording, photographing, voice recording, etc., so as to provide effective on-site video 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 cameras 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 camera meet high imaging quality is an urgent problem to be solved at present. Summary of the Invention

[0004] Aiming at the above problems, the purpose 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 sequentially includes from the object side to the imaging surface along the optical axis:

[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 total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.7 < TTL / f < 2; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1.3 < 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 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 of the first lens and the half-aperture d12 of the image side 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 matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, improve the imaging quality of the optical lens, and make the lens have one or more advantages such as miniaturization, large field of view 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 the MTF curve diagram of the optical lens in Example 1 of the present invention.

[0032] Figure 7 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0033] Figure 8 4 is a field curvature curve diagram of the optical lens in Example 2 of the present invention.

[0034] Fig. 9 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 2 of the present invention.

[0035] Fig.10 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0036] Fig.11 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0037] Fig.12 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0038] Fig.13 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0039] Fig.14 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0040] Fig.15 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 3 of the present invention.

[0041] Fig.16 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0042] Fig.17 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0043] Fig.18 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

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

[0045] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0046] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0047] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0048] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0049] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0050] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0051] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0052] The optical lens provided by the embodiment of the present invention is composed of six lenses, which are, in order from the object side to the imaging surface along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a 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 a diaphragm, and the diaphragm may be located between the first lens and the object side. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image.

[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 glued lens, and the fourth lens and the fifth lens may be glued together to form a glued 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 technology 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 of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 11 < IH / EPD < 14. Meeting the above range enables all subjects to be 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 and 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 of view angle 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, a larger image plane is obtained, enabling high-definition imaging by matching a larger-sized imaging chip and achieving a better balance between the small total length and large image plane of the lens. More specifically, 1.38 < TTL / IH < 1.56.

[0061] In some embodiments, the maximum field of view angle 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 of view angle and f-number, enabling it to 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 of view angle FOV of the optical lens, and the true image height IH corresponding to the maximum field of view angle 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 of view angle, and image height of the optical lens, thereby enabling the optical lens to have good optical performance and being able to capture the details of the object to be photographed well. More specifically, 72.81° < (f × FOV) / IH < 78.72°.

[0063] In some embodiments, the true image height IH corresponding to the maximum field of view angle 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 and controlling the image height and focal length of the optical lens within a reasonable range contribute to the optical lens having the characteristic of a large image plane and improving 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, facilitating the reasonable arrangement of the positions of each lens and reducing the processing and assembly difficulty at the same time. 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 beneficial 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 of view angle of the optical lens, and the true image height IH corresponding to the maximum field of view 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 of view angle, and large image plane of the optical lens, which is beneficial 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, reasonably matching the aperture ratios of the first lens and the sixth lens is convenient for structural design and helps 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 a positive refractive power is beneficial 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 beneficial to balance various aberrations of the system and improve 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. When the above range is satisfied, 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, balance the aberration of the optical lens, and improve 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. When the above range is satisfied, the deflection angle of the light can be reduced, making the light path more stable; at the same time, it can correct coma and field curvature, improve the flatness of the image, 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. When the above range is satisfied, by reasonably setting the focal length relationship of the cemented lens, on the one hand, the chromatic aberration of the system can be effectively corrected, the imaging quality can be improved, and at the same time, the image quality of the optical system can be effectively improved, the light energy loss can be reduced, and the imaging clarity can be increased. 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. When the above range is satisfied, 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 curvature radius R1 of the object side surface of the first lens satisfy: -24 < R1 / f < -18; the curvature radius R1 of the object side surface of the first lens and the curvature radius 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 of view angle and at the same time controlling the front aperture of the optical lens, achieving the balance between a large field of view and miniaturization. More specifically, -23.34 < R1 / f < -18.43; 0.73 < (R1 + R2) / (R1 - R2) < 0.92.

[0076] In some embodiments, the curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: 0 < (R3 + R4) / (R3 - R4) < 0.5. Satisfying the above range can effectively reduce the degree of deflection of light 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 curvature radius R10 of the image side surface of the fifth lens and the curvature radius 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 deflection of light 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 into the rear optical system, achieving a large field of view 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 < f2 / 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 of view 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 radius of curvature R10 of the image side surface of the fifth lens satisfy: 1.2 < R10 / f < 3.7. Meeting the above conditions, by reasonably controlling the focal length of the fifth lens and the surface shape of the image side surface, the spherical aberration introduced by the front optical system can be effectively compensated, 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. Meeting the above range can effectively balance various aberrations generated by the front lens group, and at the same time is beneficial to increasing the divergence degree of light, increasing the area of light entering the imaging surface, realizing large target surface imaging of the lens, and improving the imaging quality of the optical lens. More specifically, -2.91 < f6 / f < 2.11.

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

[0083] In some embodiments, the sagittal height Sag12 of the clear aperture of the image side surface of the sixth lens and the clear aperture semi-diameter d12 of the image side surface of the sixth lens satisfy: 0.1 < Sag12 / d12 < 0.2. Meeting the above range 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 principal 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 of view angle of the optical lens, and IH represents the true image height corresponding to the maximum field of view 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 of view 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. Additionally, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected due to 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] Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients respectively.

[0090] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0091] Example 1

[0092] See also Figure 1 , shown is a schematic diagram of the structure of the optical lens 100 provided in Example 1 of the present invention, and the optical lens includes, along the optical axis from the object side to the imaging surface, an aperture ST, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a filter G1.

[0093] The first lens L1 has negative refractive power, its object side surface S1 is concave, and its image side surface S2 is concave;

[0094] The second lens L2 has positive refractive power, its object-side surface S2 is convex, and its image-side surface S3 is convex;

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

[0096] The third lens L3 has positive refractive power, its object-side surface S4 is convex, and its image-side surface S5 is convex;

[0097] The fourth lens L4 has positive refractive power, its object-side surface S6 is convex, and its image-side surface S7 is convex;

[0098] The fifth lens L5 has negative refractive power, its object-side surface S7 is concave, and its image-side surface S8 is concave;

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

[0100] The sixth lens L6 has negative refractive power, its object-side surface S9 is convex, and its image-side surface S10 is concave;

[0101] The object side surface S11 and the image side surface S12 of the filter G1 are both planes;

[0102] The imaging surface S13 is a plane.

[0103] The sixth lens L6 is a glass aspherical lens, and 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 parameters of the aspheric 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 indicates the degree of curvature of light in the meridional image plane and the sagittal image plane, the horizontal axis indicates the offset (unit: mm), and the vertical axis indicates the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.4mm, 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 of different field angles on the imaging plane, with the horizontal axis representing the distortion value (unit: %) and the vertical axis representing the half field angle (unit: °). It can be seen from the figure that the distortion value is controlled within -50% to 0, indicating that the optical lens 100 can correct the distortion well.

[0112] Figure 4 The axial aberration curve of the optical lens 100 in this embodiment is shown, which represents the aberration of each wavelength on the optical axis at the imaging surface, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the figure that the offset of the axial aberration is controlled within 0 to 0.04 mm, indicating that the optical lens 100 can correct the axial aberration well.

[0113] Figure 5The vertical axis chromatic aberration curve of the optical lens 100 in this embodiment is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.546 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical axis chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4 μm, indicating that the optical lens 100 can correct chromatic aberration well.

[0114] Figure 6 The modulation transfer function (MTF) curve of the optical lens 100 in this embodiment is shown, which represents the imaging modulation degree of the lens 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. It can be seen from the figure that the MTF value of this embodiment is above 0.3 in the whole field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency conditions.

[0115] Example 2

[0116] See also Figure 7 , which is a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention.

[0117] Compared with Example 1, the main difference is that the optical parameters such as the curvature radius of each lens surface and the lens thickness 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 parameters of the aspheric 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, vertical axis chromatic aberration curve, and MTF curve of the optical lens 200 are shown in FIG. Figure 8 , Fig. 9 , Fig.10 , Fig.11 , Fig.12 shown.

[0126] from Figure 8 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.4 mm, indicating that the optical lens 200 can correct the field curvature well.

[0127] from Fig. 9 It can be seen from the figure that the distortion value is controlled within the range of -50% to 0, which indicates that the optical lens 200 can correct the distortion well.

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

[0129] from Fig.11 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±4 μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0130] from Fig.12 It can be seen that the MTF value of this embodiment is above 0.3 in the entire field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, with good imaging quality and good detail resolution in both low-frequency and high-frequency conditions.

[0131] Example 3

[0132] See also Fig.13 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main differences of this embodiment are: the image side surface of the fourth lens L4 is a concave surface; the object side surface of the fifth lens L5 is a convex surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness 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 parameters of the aspheric 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, vertical axis chromatic aberration curve, and MTF curve of the optical lens 300 are shown as follows: Fig.14 , Fig.15 , Fig.16 , Fig.17 , Fig.18 shown.

[0140] from Fig.14 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.2mm, indicating that the optical lens 300 can correct the field curvature well.

[0141] from Fig.15 It can be seen from the figure that the distortion value is controlled within the range of -50% to 0, which indicates that the optical lens 300 can correct the distortion well.

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

[0143] from Fig.17 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0144] from Fig.18 It can be seen that the MTF value of this embodiment is above 0.45 in the entire field of view, and the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, with good imaging quality and good detail resolution in both low-frequency and high-frequency conditions.

[0145] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view angle, the chief ray incident angle CRA at the maximum image height, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0146] Table 4

[0147]

[0148]

[0149] In summary of the above embodiments, the optical lens provided by the present invention adopts six lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it is possible to improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as miniaturization, a large field of view, a small aperture, and a large depth of field.

[0150] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0151] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, consisting of six lenses, characterized in that: It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with negative optical power, whose object side is concave and whose image side is concave; A second lens with positive optical power, whose object side is convex and whose image side is convex; A third lens with positive optical power, whose object side is convex and whose image side is convex; A fourth lens with positive optical power, whose object side is convex; A fifth lens with negative optical power, whose image side is concave; A sixth lens with 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 of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 11 < IH / EPD < 14.

2. The optical lens according to claim 1, characterized in that: 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.

3. The optical lens according to claim 1, characterized in that: The maximum field of view 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 of view angle FOV of the optical lens and the true image height IH corresponding to the maximum field of view 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 of view 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 overall 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 of view angle of the optical lens and the true image height IH corresponding to the maximum field of view 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