Optical lens

Abstract

The present invention provides an optical lens. The number of lenses with optical power is six. Along the optical axis from the object side to the imaging surface, it successively includes: a first lens with positive optical power, the object side surface of which is convex; a second lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; a third lens with negative optical power, the object side surface of which is convex and the image side surface of which is concave; a fourth lens with positive optical power, the object side surface of which is convex; a fifth lens with positive optical power, the object side surface of which is concave and the image side surface of which is convex; a sixth lens with negative optical power, and the sixth lens is a meniscus lens. Wherein, the true 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 optical lens provided by the present invention 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 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.

[0008] Further preferably, the overall 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 true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.8 < IH / EPD < 1.

[0010] Further preferably, the half-aperture of the object side d1 of the first lens, the true 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 sagittal height SAG7 of the object side half-aperture of the fourth lens, the sagittal height SAG8 of the image side half-aperture of the fourth lens, and the central 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 uses six lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the receiving quality of the lens, reduce aberration, improve the imaging quality of the lens, and endow the lens with one or more advantages such as a large image plane, miniaturization, a 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 be readily understood from the description of the embodiments in conjunction with the following drawings, in which: 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 an aperture, which may be located between the filter and the first lens. It can be understood that the aperture is used to limit the amount of incident light to change the brightness of the image.

[0046] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 3mm < IH / Fno < 5.8mm. Meeting the above conditions, while maintaining a large image plane for the optical lens, it ensures that the optical lens has a relatively large aperture, achieving a balance between a large image plane and a large aperture.

[0047] In some embodiments, the chief ray angle of incidence CRA at the maximum image height of the optical lens and the distance BL from the image side of the sixth lens to the imaging plane on the optical axis satisfy: 0.1mm < tan(CRA) × BL < 0.3mm. Meeting the above conditions, the chief ray incident angle of the maximum field of view of the optical lens is small, 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 beneficial to accurately receive light.

[0048] In some embodiments, 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. Meeting the above conditions, the first lens and the second lens form a thick lens group and form a positive refractive power, causing the light to converge moderately.

[0049] In some embodiments, the overall 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, the length of the lens can be effectively limited, which is beneficial to achieving miniaturization of the optical lens.

[0050] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.8 < IH / EPD < 1. Meeting the above range, while the optical lens meets the requirement of a large image plane, it can also ensure sufficient image plane brightness in the edge field of view, preventing the occurrence of vignetting, thereby improving the imaging quality.

[0051] In some embodiments, the half clear aperture d1 of the object side of the first lens, the true 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 between the size of the optical lens, the field angle, and the image plane.

[0052] In some embodiments, the sagittal height SAG7 of the clear aperture semi-diameter on the object side of the fourth lens, the sagittal height SAG8 of the clear aperture semi-diameter on the image side of the fourth lens, and the central thickness CT4 of the fourth lens satisfy: -0.55 < (SAG8 - SAG7) / CT4 < -0.25. Satisfying the above conditions can control the surface shape 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 shape of this surface from being too curved and complex, making the system field curvature tend 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. Satisfying the above conditions, the fourth lens is a positive lens, and the effective focal length of the fourth lens is relatively small. It transmits the light beam to the final imaging lens group, and realizes aberration complementarity 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. Satisfying the above range can make the fourth lens have an appropriate surface shape, 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 shape of the third lens satisfying the above conditions is beneficial to the divergence of light rays, obtaining a larger picture, effectively eliminating aberrations, and improving the resolution ability 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. Satisfying the above conditions can optimize the manufacturing tolerance and improve the yield.

[0057] In some embodiments, 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: 0.9 < d1 / d12 < 1.2. Satisfying 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, and can better meet the balance of miniaturization and high pixels.

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

[0059] In some embodiments, the sagittal height SAG11 of the clear aperture semi-diameter on the object side of the sixth lens, the sagittal height SAG12 of the clear aperture semi-diameter on the image side of the sixth lens, and the central thickness CT6 of the sixth lens satisfy: 0.1 < (SAG12 - SAG11) / CT6 < 0.5. Meeting the above conditions, by controlling the relationship between the height difference of the sagittal heights of the image side and the object side of the sixth lens and the central thickness of the sixth lens, it is beneficial to correct the coma of the off-axis field of view and improve the imaging quality of the off-axis field of view of the optical lens.

[0060] In some embodiments, the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 3 < TTL / IH < 5. Meeting the above conditions can better achieve the miniaturization of the lens. At the same time, when ensuring the same overall length of the lens, it has a larger image plane and can match a larger-sized imaging chip to achieve high-definition imaging.

[0061] In some embodiments, the effective focal length f of the optical lens, the maximum field angle FOV of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 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, improving the resolving power of the optical lens. At the same time, it meets the special distortion specifications, ensuring that the marginal field of view occupies a larger proportion in the entire imaging picture and making the imaging of the edge of the field of view clearer.

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

[0063] In some embodiments, the true image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 0.3 < IH / f < 0.4. Meeting the above conditions can achieve the characteristics of a large image plane 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 from the image side of the sixth lens to the imaging surface on the optical axis 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 components, and reducing the assembly process difficulty of the camera module.

[0065] In some embodiments, the overall optical length TTL of the optical lens, the true image height IH corresponding to the maximum field angle of the optical lens, and the maximum field angle FOV of the optical lens satisfy: 0.15 < 1°×TTL / IH / FOV < 0.25. Meeting the above range can achieve a balance among 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 angle FOV of the optical lens, and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 52° < f×FOV / IH < 63°. Meeting the above conditional formula is beneficial to achieving the balance of the field angle and large target surface imaging of the optical lens by reasonably restricting the relationship among the focal length, field angle, and image height of the optical lens, and better meeting the use requirements of high image quality shooting of the optical lens.

[0067] In some embodiments, 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 satisfy: 0.35 < ∑CT / TTL < 0.5. Meeting the above range can effectively compress the overall length of the lens and is beneficial to the structural design and production process of the lens.

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

[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 moderately converges, which can balance the aberration contributions of the front group and the rear group and avoid the deterioration of the 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 light path direction, provide a more reasonable light incident angle for the 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 lens of the 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 has a positive optical power, which can further focus the light, optimize the imaging quality, and correct the remaining aberrations (such as distortion, chromatic aberration, etc.), thereby ensuring the imaging clarity and color restoration.

[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 too large marginal ray angles and 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 aberration of the optical lens can be further compensated and adjusted to achieve higher imaging performance of the optical lens.

[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 aberration of the optical lens can be further compensated and adjusted to achieve higher imaging performance of the optical lens. Optionally, for an optical lens applied to lidar reception, high-quality collimation performance can be achieved.

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

[0077] In some embodiments, the object-side curvature radius R1 of the first lens and the effective focal length f of the optical lens satisfy: 0.45 < R1 / f < 4.6; the image-side curvature radius R2 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, the light can enter the rear optical system smoothly, thereby slowing down the trend of marginal rays, which is beneficial to reducing the incident angles of the 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 light deflection angle and make the light path more stable; at the same time, it can correct coma and field curvature, improve the flatness of imaging, and enhance the imaging quality of the optical lens.

[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 collect the converged light beam, and also can ease the light path after passing through the sixth lens, which helps to achieve a small CRA and high imaging quality of the optical lens.

[0080] In some embodiments, the optical lens satisfies the conditional formula: 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 overall optical length of the optical lens, Fno represents the aperture value of the optical lens, CRA represents the principal ray incident angle at the maximum image height of the optical lens, BL represents the distance from the image side surface of the sixth lens to the imaging surface on the optical axis, FOV represents the maximum field angle of the optical lens, and IH represents the true image height corresponding to the maximum field angle of the optical lens. 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 a large image plane, miniaturization, and a small CRA.

[0081] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. 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 enhance 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 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 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, It successively includes from the object side to the imaging surface along the optical axis: A first lens with positive optical power, whose object side is convex; A second lens with positive optical power, whose object side is convex and whose image side is concave; A third lens with negative optical power, whose object side is convex and whose image side is concave; A fourth lens with positive optical power, whose object side is convex; A fifth lens with positive optical power, whose object side is concave and whose image side is convex; A sixth lens with negative optical power, and the sixth lens is a meniscus lens; Wherein, the true image height IH corresponding to the maximum field angle of the optical lens and the aperture value Fno of the optical lens satisfy: 3mm < IH / Fno < 5.8mm.

2. The optical lens according to claim 1, characterized in that, The principal ray incident angle CRA at the maximum image height of the optical lens and the distance BL on the optical axis from the image side of the sixth lens to the imaging surface satisfy: 0.1mm < tan(CRA)×BL < 0.3mm.

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 overall 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 true image height IH corresponding to the maximum field angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.8 < IH / EPD < 1.

6. The optical lens according to claim 1, characterized in that, The clear aperture radius d1 of the object side of the first lens, the true 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.

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

25.

8. 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.

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

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

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