Optical lens

Abstract

The application provides an optical lens, which has six lenses with optical power, and sequentially comprises, along an optical axis from an object side to an imaging surface, a first lens with positive optical power, whose object side surface is a convex surface; a second lens with positive optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; a third lens with negative optical power, whose object side surface is a convex surface and whose image side surface is a concave surface; a fourth lens with positive optical power, whose object side surface is a convex surface; a fifth lens with positive optical power, whose object side surface is a concave surface and whose image side surface is a convex surface; and a sixth lens with negative optical power, which is a meniscus lens; wherein a real image height IH corresponding to a maximum field angle of the optical lens and an aperture value Fno of the optical lens satisfy 3mm<IH / Fno<5.8mm. The optical lens provided by the application reduces aberration and improves the imaging quality of the lens through specific surface shape matching and reasonable optical power distribution.

Description

Technical Field

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

[0002] Today, lidar is widely used for detecting the three-dimensional coordinates and ranging of objects. A lidar system includes a controller, a light source, and a receiver. The controller controls the light source to emit a light beam. When the beam encounters a target object, it undergoes diffuse reflection. The receiver receives the reflected beam and uses the information from both the emitted and reflected beams to determine relevant information about the target object, such as its distance, orientation, height, speed, attitude, and even shape. LiDAR is widely used in autonomous vehicles, drones, autonomous robots, lawnmowers, and more.

[0003] As a key component of lidar, the optical lens receives and processes reflected light. With the ever-increasing performance requirements of lidar applications, optical lens parameters need to evolve towards larger apertures, wider fields of view, and lower aberrations to meet the growing demands for high-precision, wide-coverage detection. Currently, lidar optical lenses suffer from low image quality, failing to meet market demands. Summary of the Invention

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

[0005] This invention provides an optical lens comprising six lenses with optical power, arranged sequentially along the optical axis from the object side to the imaging plane: A first lens with positive optical power has a convex object-side surface. A second lens with positive optical power has a convex object-side surface and a concave image-side surface; A third lens with negative optical power has a convex object side and a concave image side. The fourth lens has positive optical power and its object side is convex. The fifth lens with positive optical power has a concave object side and a convex image side. A sixth lens with negative optical power, wherein the sixth lens is a meniscus lens; Wherein, the true image height IH corresponding to the maximum field of view of the optical lens and the aperture value Fno of the optical lens satisfy: 3mm <IH / Fno<5.8mm。

[0006] Further preferably, the incident angle CRA of the principal ray at the maximum image height of the optical lens and the distance BL on the optical axis from the image side surface of the sixth lens to the imaging plane satisfy: 0.1mm. <tan(CRA)×BL<0.3mm。

[0007] Further preferably, the center thickness CT1 of the first lens, the center thickness CT2 of the second lens and the focal length f1 of the first lens satisfy: 0.1<(CT1+CT2) / f1<0.35.

[0008] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1<TTL / f<1.7.

[0009] Further preferably, 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 satisfy: 0.8<IH / EPD<1.

[0010] Further preferably, the clear half aperture d1 on the object side of the first lens, the real image height IH corresponding to the maximum field angle of the optical lens and the maximum field angle FOV of the optical lens satisfy: 2.6<d1 / IH / tan(FOV / 2)<3.6.

[0011] Further preferably, the clear half aperture sag SAG7 on the object side of the fourth lens, the clear half aperture sag SAG8 on the image side of the fourth lens and the center thickness CT4 of the fourth lens satisfy: -0.55<(SAG8-SAG7) / CT4<-0.25.

[0012] Further preferably, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6<f4 / f<0.8.

[0013] Further preferably, the radius of curvature R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: 0.55<R7 / f<0.8; the radius of curvature R8 of the image side of the fourth lens and the effective focal length f of the optical lens satisfy: -5.5<R8 / f<6.6.

[0014] Further preferably, the radius of curvature R5 of the object side of the third lens and the radius of curvature R6 of the image side of the third lens satisfy: 0.8<(R5-R6) / (R5+R6)<1.

[0015] 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 receiving quality of the lens, reduce aberrations, and improve the imaging quality of the lens, so that the lens has one or more advantages such as large image plane, miniaturization, small CRA, and high collimation performance. Brief Description of the Drawings

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of the embodiments in conjunction with the accompanying drawings as follows: Figure 1 This is a schematic diagram of the optical lens structure in Embodiment 1 of the present invention.

[0017] Figure 2 This is a field curvature curve diagram of the optical lens in Embodiment 1 of the present invention.

[0018] Figure 3 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 1 of the present invention.

[0019] Figure 4 This is an axial aberration curve of the optical lens in Embodiment 1 of the present invention.

[0020] Figure 5 This is a chromatic aberration curve of the optical lens in Embodiment 1 of the present invention.

[0021] Figure 6 This is a relative illumination curve of the optical lens in Embodiment 1 of the present invention.

[0022] Figure 7 This is a schematic diagram of the optical lens structure in Embodiment 2 of the present invention.

[0023] Figure 8 This is a field curvature curve diagram of the optical lens in Embodiment 2 of the present invention.

[0024] Figure 9 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 2 of the present invention.

[0025] Figure 10 This is an axial aberration curve of the optical lens in Embodiment 2 of the present invention.

[0026] Figure 11 This is a chromatic aberration curve of the optical lens in Embodiment 2 of the present invention.

[0027] Figure 12 This is a relative illumination curve of the optical lens in Embodiment 2 of the present invention.

[0028] Figure 13 This is a schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0029] Figure 14 This is a field curvature curve diagram of the optical lens in Embodiment 3 of the present invention.

[0030] Figure 15 This is an F-Tan (Theta) distortion curve of the optical lens in Embodiment 3 of the present invention.

[0031] Figure 16 This is an axial aberration curve of the optical lens in Embodiment 3 of the present invention.

[0032] Figure 17 This is a chromatic aberration curve of the optical lens in Embodiment 3 of the present invention.

[0033] Figure 18 This is a relative illumination curve of the optical lens in Embodiment 3 of the present invention.

[0034] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The optical lens provided in this embodiment of the invention can be used as a receiving lens for lidar, transmitting light reflected from the surface of an object to the imaging plane. The optical lens of this invention has six lenses with optical power, sequentially comprising, along the optical axis from the object side to the imaging plane: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens.

[0043] In some embodiments, the first lens may have positive optical power, with its object-side surface being convex and its image-side surface being either concave or convex. The second lens may have positive optical power, with its object-side surface being convex and its image-side surface being concave. The third lens may have negative optical power, with its object-side surface being convex and its image-side surface being concave. The fourth lens may have positive optical power, with its object-side surface being convex and its image-side surface being either concave or convex. The fifth lens may have positive optical power, with its object-side surface being concave and its image-side surface being convex. The sixth lens may have negative optical power, with its object-side surface being either concave or convex and its image-side surface being either concave or convex; the sixth lens may be a meniscus lens.

[0044] In some embodiments, the optical lens may further include a filter disposed between the object side and the first lens. The filter is used to filter out interfering light and prevent interfering light from reaching the first lens of the optical lens and affecting normal imaging.

[0045] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the filter and the first lens. It can be understood that the diaphragm is used to limit the amount of incoming light to change the brightness of the formed image.

[0046] In some embodiments, the real image height IH corresponding to the maximum field angle of the optical lens and the F-number Fno of the optical lens satisfy: 3mm<IH / Fno<5.8mm. Meeting the above conditions ensures that the optical lens maintains a large image surface while having a relatively large aperture, achieving a balance between a large image surface and a large aperture.

[0047] In some embodiments, the chief ray incidence angle CRA at the maximum image height of the optical lens and the distance BL on the optical axis from the image side surface of the sixth lens to the imaging surface satisfy: 0.1mm<tan(CRA)×BL<0.3mm. Meeting the above conditions results in a small chief ray incidence angle at the maximum field of view of the optical lens, which is beneficial to ensuring a high receiving efficiency of the imaging chip and improving the imaging quality of the optical lens. In particular, for an optical lens applied to LiDAR reception, it is conducive to accurate light reception.

[0048] In some embodiments, the center thickness CT1 of the first lens, the center thickness CT2 of the second lens, and the focal length f1 of the first lens satisfy: 0.1<(CT1+CT2) / f1<0.35. Meeting the above conditions, the first lens and the second lens form a thick lens group and have positive refractive power, so that the light rays converge moderately.

[0049] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1<TTL / f<1.7. Meeting the above conditions can effectively limit the length of the lens, which is beneficial to realizing the miniaturization of the optical lens.

[0050] In some embodiments, 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 satisfy: 0.8<IH / EPD<1. Meeting the above range enables the optical lens to satisfy the requirement of a large image surface while ensuring sufficient image surface brightness at the edge field of view, preventing vignetting and thus improving the imaging quality.

[0051] In some embodiments, the clear aperture half-diameter d1 of the object side surface of the first lens, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 2.6<d1 / IH / tan(FOV / 2)<3.6. Meeting the above range can ensure the balance among the size, the field angle and the image surface of the optical lens.

[0052] In some embodiments, the sag height SAG7 of the clear aperture half-diameter on the object side of the fourth lens, the sag height SAG8 of the clear aperture half-diameter on the image side of the fourth lens, and the center thickness CT4 of the fourth lens satisfy: -0.55<(SAG8-SAG7) / CT4<-0.25. Meeting the above conditions can control the surface profile of the fourth lens, which is beneficial to the manufacture and molding of the fourth lens and reduces the defective rate. In addition, it can also avoid the surface profile of this surface being too curved and complex, so that the field curvature of the system tends to be balanced.

[0053] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6<f4 / f<0.8. Meeting the above conditions, the fourth lens is a positive lens, and the effective focal length of the fourth lens is small, which transmits the light beam to the final imaging lens group, and realizes aberration complementation with the front and rear optical systems, thereby achieving high imaging quality of the optical lens.

[0054] In some embodiments, the radius of curvature R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: 0.55<R7 / f<0.8; the radius of curvature R8 of the image side of the fourth lens and the effective focal length f of the optical lens satisfy: -5.5<R8 / f<6.6. Meeting the above ranges can make the fourth lens have an appropriate surface profile, which is beneficial to balancing the astigmatism and field curvature of the optical lens and improving the imaging quality of the optical lens.

[0055] In some embodiments, the radius of curvature R5 of the object side of the third lens and the radius of curvature R6 of the image side of the third lens satisfy: 0.8<(R5-R6) / (R5+R6)<1. The surface profile of the third lens that meets the above conditions is beneficial to diverging light rays, obtaining a larger picture, effectively eliminating aberrations, and improving the resolution capability of the optical lens.

[0056] In some embodiments, the distance CT23 between the second lens and the third lens on the optical axis and the total optical length TTL of the optical lens satisfy: 0.02<CT23 / TTL<0.08. Meeting the above conditions can optimize manufacturing tolerance and improve the yield.

[0057] In some embodiments, the clear aperture half-diameter d1 of the object side of the first lens and the clear aperture half-diameter d12 of the image side of the sixth lens satisfy: 0.9<d1 / d12<1.2. Meeting the above range, by reasonably setting the ratio of the apertures of the first and last lenses, the lens can have a smaller head size while having a larger imaging surface, which can better meet the balance of miniaturization and high pixels.

[0058] In some embodiments, the sag SAG3 of the clear aperture half-diameter on the object side of the second lens, the sag SAG4 of the clear aperture half-diameter on the image side of the second lens, and the center thickness CT2 of the second lens satisfy: -0.3<(SAG4-SAG3) / CT2<-0.1. Satisfying the above conditions can limit the degree of central depression of the second lens and reduce the difficulty of aberration correction at the marginal field of view.

[0059] In some embodiments, the sag SAG11 of the clear aperture half-diameter on the object side of the sixth lens, the sag SAG12 of the clear aperture half-diameter on the image side of the sixth lens, and the center thickness CT6 of the sixth lens satisfy: 0.1<(SAG12-SAG11) / CT6<0.5. Satisfying the above conditions, by controlling the relationship between the sag height difference between the image side and the object side of the sixth lens and the center thickness of the sixth lens, is beneficial for correcting coma in the off-axis field of view, and helps improve the imaging quality of the off-axis field of view of the optical lens.

[0060] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3<TTL / IH<5. Satisfying the above conditions can better realize the miniaturization of the lens, and at the same time ensure that under the condition of the same total length of the lens, the lens has a larger image plane, which can match an imaging chip of a larger size to achieve high-definition imaging.

[0061] 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 real image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.9<(IH / 2) / (f×tan(FOV / 2))<1.1. Meeting the above requirements indicates that the optical distortion of the optical lens is well controlled, the resolving power of the optical lens is improved, and a special distortion specification is achieved at the same time, ensuring that the marginal field of view occupies a larger proportion in the entire imaging frame, so that the edge imaging of the field of view is clearer.

[0062] In some embodiments, the maximum field of view angle FOV of the optical lens and the F-number Fno of the optical lens satisfy: 7°<FOV / Fno<9.5°. Satisfying the above conditions is beneficial to increasing the light intake of the lens, enabling the lens to perform high-definition imaging even in a dim environment.

[0063] In some embodiments, the real 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: 0.3<IH / f<0.4. Satisfying the above conditions can realize the large image plane characteristic while ensuring the depth of field of the optical lens, thereby improving the imaging quality of the optical system.

[0064] In some embodiments, the distance BL on the optical axis from the image side surface of the sixth lens to the imaging surface and the effective focal length f of the optical lens satisfy: 0.06<BL / f<0.2. Meeting the above range is beneficial to achieving a balance between obtaining good imaging quality and easy assembly, ensuring the imaging quality of the optical lens while avoiding interference between the lens and other elements, and reducing the difficulty of the assembly process of the camera module.

[0065] In some embodiments, the total optical length TTL of the optical lens, the real image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.15<1°×TTL / IH / FOV<0.25. Meeting the above range can achieve a balance between large image height, long focal length and miniaturization, and improve the imaging quality of the optical lens.

[0066] 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 real image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 52°<f×FOV / IH<63°. Meeting the above conditional expressions, by reasonably limiting the relationship among the focal length, field of view angle and image height of the optical lens, is conducive to realizing the balance between the field of view angle of the optical lens and large target surface imaging, and better meets the use requirements of the optical lens for high-image-quality shooting.

[0067] In some embodiments, the total optical length TTL of the optical lens and the sum ΣCT of the central thicknesses of the first lens to the sixth lens along the optical axis respectively satisfy: 0.35<ΣCT / TTL<0.5. Meeting the above range can effectively compress the total length of the lens, and is beneficial to the structural design and production process of the lens at the same time.

[0068] In some embodiments, the distance BL on the optical axis from the image side surface of the sixth lens to the imaging surface and the total optical length TTL of the optical lens satisfy: 0.06<BL / TTL<0.15. Meeting the above range is beneficial to realizing the short back focal length of the optical lens, and is conducive to the miniaturization of the optical lens while ensuring sufficient space for the installation of optical elements.

[0069] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 0.6<f1 / f<3. Meeting the above conditions, the first lens appropriately converges light, which can balance the aberration contributions of the front group and the rear group, and avoid the deterioration of image quality in the marginal field of view.

[0070] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: 1<f2 / f<2.5. Meeting the above conditions can control the direction of the optical path, provide a more reasonable incident angle of light for subsequent lenses, and reduce astigmatism and field curvature.

[0071] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: -0.7<f3 / f<-0.2. Meeting the above conditions, the negative power third lens can adjust the chief ray angle and reduce the barrel distortion of the wide-angle lens.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.2<f5 / f<6. Meeting the above conditions, the fifth lens with positive optical power can further converge light, optimize imaging quality, and correct residual aberrations (such as distortion, chromatic aberration, etc.), so as to ensure imaging clarity and color reproduction accuracy.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -5<f6 / f<-0.95. Meeting the above conditions, the sixth lens can extend the light convergence point and increase the back focal length; and can avoid an excessively large marginal ray angle to match the sensor CRA.

[0074] In some embodiments, the focal length f4 of the fourth lens and the focal length f5 of the fifth lens satisfy: 0.1<f4 / f5<0.6. Meeting the above conditions, the aberrations of the optical lens can be further compensated and adjusted, and high imaging performance of the optical lens can be achieved.

[0075] In some embodiments, the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -1.8<f5 / f6<-1.1. Meeting the above conditions, the aberrations of the optical lens can be further compensated and adjusted, and high imaging performance of the optical lens can be achieved. Optionally, for an optical lens applied to LiDAR reception, high-quality collimation performance can be realized.

[0076] In some embodiments, the center thickness CT5 of the fifth lens and the center thickness CT6 of the sixth lens satisfy: 1.6<CT5 / CT6<2. Meeting the above conditions, the performance sensitivity of the system can be reduced, while ensuring the machinability of the lenses and assembly stability, and improving the assembly yield.

[0077] In some embodiments, the curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: 0.45<R1 / f<4.6; the curvature radius R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: -8.3<R2 / f<5.5. Meeting the above conditions, light can enter the rear optical system gently, thereby slowing down the trend of marginal rays, which is beneficial to reducing the incident angle of chief rays in each field of view, and improving the imaging quality of the optical lens.

[0078] In some embodiments, the radius of curvature R9 of the object-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -2.3 < R9 / f < -0.36; the radius of curvature R10 of the image-side surface of the fifth lens and the effective focal length f of the optical lens satisfy: -0.85 < R10 / f < -0.36. Satisfying the above ranges can reduce the deflection angle of light rays and make the light ray trend 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.

[0079] In some embodiments, the radius of curvature R11 of the object-side surface of the sixth lens and the radius of curvature R12 of the image-side surface of the sixth lens satisfy: 0.1 < R11 / R12 < 2.4. Satisfying the above conditions, and the sixth lens being a meniscus lens, can effectively converge and bundle the converged light beam, and can also moderate the path of light rays after passing through the sixth lens, which is helpful to achieve small CRA and high imaging quality of the optical lens.

[0080] In some embodiments, the optical lens satisfies the conditional expressions: 24mm < f < 40mm, 9mm < EPD < 16mm, 37mm < TTL < 45mm, 2.2 < Fno < 2.8, 2.9° < CRA < 3.4°, 2.4mm < BL < 4mm, 19° < FOV < 23°, 8mm < IH < 14mm; where f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the F-number of the optical lens, CRA represents the chief ray incident angle at the maximum image height of the optical lens, BL represents the distance on the optical axis from the image-side surface of the sixth lens to the imaging plane, FOV represents the maximum field of view of the optical lens, and IH represents the real image height corresponding to the maximum field of view of the optical lens. Satisfying the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least one or more advantages such as large image plane, miniaturization, and small CRA.

[0081] In some embodiments, the material of the lenses in the optical lens provided by the present invention can be glass or plastic. When the material of the lens is plastic, the production cost can be effectively reduced. In addition, when the material of the lens is glass, the geometric chromatic aberration of the optical system can be effectively corrected by utilizing the low dispersion characteristic of glass itself. The lens provided by the present invention can adopt an all-glass lens structure, which can reduce dispersion, effectively correct the chromatic aberration of the optical lens, and improve the imaging quality.

[0082] In some embodiments, the first, second, third, fourth, fifth, and sixth lenses can be spherical or aspherical lenses. Compared to spherical structures, aspherical structures can effectively reduce the aberrations of the optical system, thereby reducing the number of lenses and their size, and better achieving lens miniaturization. More specifically, the first, second, third, fourth, fifth, and sixth lenses of this invention are all spherical lenses.

[0083] 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.

[0084] Example 1

[0085] Please see Figure 1 The figure shown is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, along the optical axis from the object side to the imaging surface, the following components in sequence: filter G1, aperture ST, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, and sixth lens L6.

[0086] The object-side surface S1 and the image-side surface S2 of filter G1 are both planar. The first lens L1 has positive optical power, its object side S3 is convex, and its image side S4 is convex. The second lens L2 has positive optical power, its object side S5 is convex, and its image side S6 is concave. The third lens L3 has negative optical power, its object side S7 is convex, and its image side S8 is concave. The fourth lens L4 has positive optical power, its object side S9 is convex, and its image side S10 is convex. The fifth lens L5 has positive optical power, its object side S11 is concave, and its image side S12 is convex. The sixth lens L6 has negative optical power, its object side S13 is concave, and its image side S14 is convex. The imaging plane S15 is a plane.

[0087] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are glass spherical lenses.

[0088] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1.

[0089] Table 1 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, and relative illumination curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown.

[0090] Figure 2 The field curvature curve of Example 1 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 ±0.1 mm, indicating that the optical lens can effectively correct the field curvature.

[0091] Figure 3 The diagram shows the F-Tan (Theta) distortion curve for Example 1, which represents the F-Tan (Theta) distortion of light at different image heights on the imaging plane. The horizontal axis represents the F-Tan (Theta) distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tan (Theta) distortion of the optical lens is controlled within -2% to 0, indicating that the optical lens can effectively correct distortion.

[0092] Figure 4 The diagram shows the axial aberration curves for Example 1, representing the aberrations of each wavelength along the optical axis. 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 diagram, the axial aberration offset is controlled within ±0.05 mm, indicating that the optical lens can effectively correct axial aberrations.

[0093] Figure 5 The diagram shows the transverse chromatic aberration curves for Example 1, representing the chromatic aberration of each wavelength relative to the center wavelength (0.905 μm) at different image heights on the imaging plane. The horizontal axis represents the transverse chromatic aberration value of each wavelength relative to the center wavelength (unit: μm), and the vertical axis represents the normalized field of view. As can be seen from the diagram, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1 μm, indicating that the optical lens can effectively correct chromatic aberration.

[0094] Figure 6The relative illumination curve of Example 1 is shown, which represents the relative illumination value at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 98% at the maximum half-field angle, indicating that the optical lens has good relative illumination.

[0095] Example 2

[0096] Please see Figure 7 The figure shows a schematic diagram of the structure of the optical lens 200 provided in Embodiment 2 of the present invention. The difference between this embodiment and Embodiment 1 is that the image-side surface S4 of the first lens L1 is concave; the image-side surface S10 of the fourth lens L4 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0097] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2.

[0098] Table 2 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, and relative illumination curve of the optical lens 200 are respectively as follows: Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 As shown.

[0099] from Figure 8 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.1mm, indicating that the optical lens can effectively correct the field curvature.

[0100] from Figure 9 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within -2% to 0, indicating that the optical lens can effectively correct distortion.

[0101] from Figure 10 As can be seen, the axial aberration offset is controlled within ±0.05mm, indicating that the optical lens can effectively correct axial aberration.

[0102] from Figure 11 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1μm, indicating that the optical lens can effectively correct chromatic aberration.

[0103] from Figure 12 As can be seen, the relative illumination value of the optical lens is still greater than 98% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0104] Example 3

[0105] 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 difference between this embodiment and Embodiment 1 is that: the image-side surface S4 of the first lens L1 is concave; the object-side surface S13 of the sixth lens L6 is convex; the image-side surface S14 of the sixth lens L6 is concave; and the optical parameters such as the radius of curvature and lens thickness of each lens surface are different.

[0106] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3.

[0107] Table 3 In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, axial aberration curve, transverse chromatic aberration curve, and relative illumination curve of the optical lens 300 are respectively as follows: Figure 14 , Figure 15 , Figure 16 , Figure 17 and Figure 18 As shown.

[0108] from Figure 14 As can be seen, the field curvature of the meridional and sagittal image planes is controlled within ±0.1mm, indicating that the optical lens can effectively correct the field curvature.

[0109] from Figure 15 As can be seen, the F-Tan (Theta) distortion of the optical lens is controlled within -2% to 0, indicating that the optical lens can effectively correct distortion.

[0110] from Figure 16 As can be seen, the axial aberration offset is controlled within ±0.05mm, indicating that the optical lens can effectively correct axial aberration.

[0111] from Figure 17 As can be seen, the transverse chromatic aberration of the longest and shortest wavelengths is controlled within ±1μm, indicating that the optical lens can effectively correct chromatic aberration.

[0112] from Figure 18 As can be seen, the relative illumination value of the optical lens is still greater than 98% at the maximum half field of view, indicating that the optical lens has good relative illumination.

[0113] 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, distance BL from the image side of the sixth lens to the imaging plane on the optical axis, and the numerical values ​​corresponding to each conditional expression in each embodiment.

[0114] Table 4 In summary, the optical lens provided by the present invention employs six lenses with specific optical power. Through specific surface shape matching and reasonable optical power distribution, it can improve the receiving quality of the lens, reduce aberrations, and enhance the imaging quality of the lens, giving the lens one or more advantages such as large image plane, miniaturization, small CRA, and high collimation performance.

[0115] 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.

[0116] 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 having optical power, characterized in that, sequentially along the optical axis from the object side to the image plane, comprising: a first lens with positive refractive power, of which the object-side surface is convex; a second lens with positive refractive power, of which the object-side surface is convex and the image-side surface is concave; a third lens with negative refractive power, of which the object-side surface is convex and the image-side surface is concave; a fourth lens with positive refractive power, of which the object-side surface is convex; a fifth lens with positive refractive power, of which the object-side surface is concave and the image-side surface is convex; a sixth lens with negative refractive power, wherein the sixth lens is a meniscus lens; wherein, the real image height IH corresponding to the maximum field angle of the optical lens and the F-number Fno of the optical lens satisfy: 3mm<IH / Fno<5.8mm; the chief ray incidence angle CRA at the maximum image height of the optical lens and the distance BL on the optical axis from the image-side surface of the sixth lens to the image plane satisfy: 0.1mm<tan(CRA)×BL<0.3mm; the clear aperture half-caliber d1 of the object-side surface of the first lens, the real image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 2.6<d1 / IH / tan(FOV / 2)<3.

6.

2. The optical lens according to claim 1, characterized in that, the clear aperture half-caliber d1 of the object-side surface of the first lens and the clear aperture half-caliber d12 of the image-side surface of the sixth lens satisfy: 0.9<d1 / d12<1.

2.

3. The optical lens according to claim 1, characterized in that, the central thickness CT1 of the first lens, the central thickness CT2 of the second lens, and the focal length f1 of the first lens satisfy: 0.1<(CT1+CT2) / f1<0.

35.

4. 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<TTL / f<1.

7.

5. The optical lens according to claim 1, characterized in that, 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 satisfy: 0.8<IH / EPD<1.

6. The optical lens according to claim 1, characterized in that, the clear aperture half-caliber sag height SAG7 of the object-side surface of the fourth lens, the clear aperture half-caliber sag height SAG8 of the image-side surface of the fourth lens, and the central thickness CT4 of the fourth lens satisfy: -0.55<(SAG8-SAG7) / CT4<-0.

25.

7. The optical lens according to claim 1, characterized in that, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6<f4 / f<0.

8.

8. The optical lens according to claim 1, characterized in that, the curvature radius R7 of the object-side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 0.55<R7 / f<0.8; the curvature radius R8 of the image-side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -5.5<R8 / f<6.

6.

9. The optical lens according to claim 1, characterized in that, the curvature radius R5 of the object-side surface of the third lens and the curvature radius R6 of the image-side surface of the third lens satisfy: 0.8<(R5-R6) / (R5+R6)<1.

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