Optical lens

Abstract

The present invention provides an optical lens having seven lenses, which include, in order from the object side to the imaging surface along the optical axis: a first lens having positive focal power, whose object side surface is convex and whose image side surface is concave; a second lens having positive focal power; a third lens having negative focal power, whose object side surface is concave and whose image side surface is concave; a fourth lens having positive focal power, whose object side surface is convex and whose image side surface is convex; a fifth lens having negative focal power, whose object side surface is concave and whose image side surface is convex; a sixth lens having positive focal power, whose object side surface is convex; and a seventh lens having negative focal power, whose object side surface is concave. The optical lens provided by the present invention has one or more advantages such as telephoto, large aperture, and high imaging quality through specific surface shape matching and reasonable focal power distribution.

Description

Technical Field

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

[0002] As people's requirements for driving experience continue to increase, automotive optical lenses are increasingly used in intelligent driving, and the status of automotive optical lenses in the automotive-related industries continues to improve.

[0003] Advanced Driver Assistance Systems (ADAS) play a crucial role in intelligent driving. They use various lenses and sensors to collect environmental information to ensure driver safety. Existing ADAS systems require not only a thin, compact form factor with high pixel count and resolution, but also the ability to produce clear images in low-light conditions. Therefore, developing an optical lens with excellent imaging performance is crucial. Summary of the Invention

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

[0005] The technical solution adopted in the present invention is:

[0006] An optical lens, comprising seven lenses, including the following elements in order from the object side to the imaging surface along the optical axis:

[0007] The first lens has positive refractive power, its object-side surface is convex and its image-side surface is concave;

[0008] a second lens having positive optical power;

[0009] a third lens element having negative optical power, whose object-side surface and image-side surface are concave;

[0010] a fourth lens element having positive refractive power, whose object-side surface is convex and whose image-side surface is convex;

[0011] a fifth lens element having negative optical power, whose object-side surface is concave and whose image-side surface is convex;

[0012] a sixth lens element having positive optical power and a convex object-side surface;

[0013] a seventh lens element having negative optical power and a concave object-side surface;

[0014] Among them, the object side curvature radius R1 of the first lens and the image side curvature radius R2 of the first lens satisfy: -0.8<(R1-R2) / (R1+R2)<-0.1; the object side curvature radius R5 of the third lens and the image side curvature radius R6 of the third lens satisfy: |(R5+R6) / (R5-R6)|<0.9.

[0015] Further preferably, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 2.5; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of the optical lens satisfy: 4 < TTL / IH < 4.8.

[0016] Further preferably, the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15° < FOV / Fno < 20°; 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.

[0017] Further preferably, 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: 6.5 < d1 / (IH / 2) / tan(FOV / 2) < 8.5; the combined focal length f123 of the first lens, the second lens, and the third lens and the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: -37 < f123 / f4567 < -5.5.

[0018] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.3 < f1 / f < 5.5; the radius of curvature R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: 0.85 < R1 / f < 1.6; the radius of curvature R2 of the image side of the first lens and the effective focal length f of the optical lens satisfy: 2 < R2 / f < 5.8.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.7 < f3 / f < -0.6; the radius of curvature R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: -4 < R5 / f < -1.3; the radius of curvature R6 of the image side of the third lens and the effective focal length f of the optical lens satisfy: 0.4 < R6 / f < 3.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.4 < f4 / f < 0.7; the radius of curvature R7 of the object side of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6 < 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: -0.65 < R8 / f < -0.3.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -2 < f5 / f < -0.9; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.65 < R9 / f < -0.3; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.2 < R10 / f < -0.6.

[0022] Further preferably, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.9 < f7 / f < -0.5; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.1 < R13 / f < -0.4.

[0023] Further preferably, the object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: -0.5 < (R9 - R10) / (R9 + R10) < -0.1; the object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: 0 < (R7 + R8) / (R7 - R8) < 0.5.

[0024] The optical lens provided by the present invention uses seven lenses with specific optical powers. Through specific surface shape combinations and reasonable optical power distributions, it can improve the imaging quality of the optical lens, reduce aberrations, and enhance the imaging quality of the optical lens, enabling the lens to have one or more advantages such as long focal length, large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

[0030] Figure 5 is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 6Graph showing the field curvature of the optical lens in Example 2 of the present invention.

[0032] Figure 7 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 2 of the present invention.

[0033] Figure 8 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0034] Figure 9 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0035] Figure 10 4 is a field curvature curve diagram of the optical lens in Example 3 of the present invention.

[0036] Figure 11 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 3 of the present invention.

[0037] Figure 12 This is the MTF curve of the optical lens in Example 3 of the present invention.

[0038] Figure 13 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

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

[0040] Figure 15 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 4 of the present invention.

[0041] Figure 16 This is the MTF curve of the optical lens in Example 4 of the present invention.

[0042] Figure 17 Schematic diagram of the structure of the optical lens in Example 5 of the present invention.

[0043] Figure 18 4 is a field curvature curve diagram of the optical lens in Example 5 of the present invention.

[0044] Figure 19 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 5 of the present invention.

[0045] Figure 20 This is the MTF curve of the optical lens in Example 5 of the present invention.

[0046] Figure 21 Schematic diagram of the structure of the optical lens in Example 6 of the present invention.

[0047] Figure 224 is a field curvature curve diagram of the optical lens in Example 6 of the present invention.

[0048] Figure 23 : This is the F-Tan (Theta) distortion curve of the optical lens in Example 6 of the present invention.

[0049] Figure 24 This is the MTF curve of the optical lens in Example 6 of the present invention.

[0050] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0051] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0052] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of the present invention.

[0053] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0054] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, 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.

[0055] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0056] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0057] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0058] The optical lens provided in an embodiment of the present invention is composed of seven lenses, which are, along the optical axis from the object side to the imaging surface, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens.

[0059] In some embodiments, the first lens may have positive optical power, its object-side surface is convex, and its image-side surface is concave. The second lens may have positive optical power, its object-side surface may be concave or convex, and its image-side surface may be concave or convex. The third lens may have negative optical power, its object-side surface is concave, and its image-side surface is concave. The fourth lens may have positive optical power, its object-side surface is convex, and its image-side surface is convex. The fifth lens may have negative optical power, its object-side surface is concave, and its image-side surface is convex. The sixth lens may have positive optical power, its object-side surface is convex, and its image-side surface may be concave or convex. The seventh lens may have negative optical power, its object-side surface is concave, and its image-side surface may be concave or convex.

[0060] In some embodiments, the optical lens may further include an aperture, which may be located between the third and fourth lenses. It is understood that the aperture is used to limit the amount of light entering, thereby changing the brightness of the image. Furthermore, when the aperture is located between the third and fourth lenses, it can effectively distribute the functions of the first through seventh lenses. For example, the first, second, and third lenses can be used to receive a greater amount of light, while the fourth through seventh lenses can be used to correct aberrations, thus balancing the structure of the entire optical system. Furthermore, when the aperture is located between the third and fourth lenses, it facilitates the correction of aperture aberrations.

[0061] In some embodiments, the optical lens may further include a filter and a protective glass. The filter and protective glass may be positioned sequentially along the optical axis between the seventh lens element and the imaging surface. The filter is used to filter out interfering light, preventing it from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass protects the optical lens from damage to the photosensitive chip and improves the optical lens's impact and scratch resistance, while having little impact on the optical lens's imaging quality.

[0062] In some embodiments, the fourth lens and the fifth lens can be cemented to form a cemented lens, which can effectively correct the chromatic aberration of the optical lens, reduce the decentration sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the difficulty of the processing technology of the optical lens and improving the assembly yield of the optical lens.

[0063] In some embodiments, the radius of curvature R1 of the object side of the first lens and the radius of curvature R2 of the image side of the first lens satisfy the following conditions: -0.8 < (R1-R2) / (R1+R2) < -0.1. When these conditions are met, the use of a meniscus lens as the first lens can further stabilize the light path, resulting in a more focused light. This can further control the light direction, reduce back focal length, improve image quality, increase light utilization, and reduce spherical aberration of the optical lens, thereby enhancing the imaging quality of the optical lens. More specifically, -0.7 < (R1-R2) / (R1+R2) < -0.17.

[0064] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy the following relationship: |(R5+R6) / (R5-R6)|<0.9. To meet this range, the third lens is biconcave, which diverges light, dispersing the central and peripheral rays of each field of view and correcting aberrations introduced by the front lens. More specifically, -0.31<(R5+R6) / (R5-R6)<0.77.

[0065] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 2.5. Meeting the above range can effectively limit the length of the lens, which is beneficial to the miniaturization of the optical lens. More specifically, 2.17 < TTL / f < 2.44.

[0066] In some embodiments, the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field angle of view of the optical lens satisfy: 4 < TTL / IH < 4.8. Meeting the above range ensures that, with the same total length of the lens, it has a larger image plane, can match a larger-sized imaging chip to achieve high-definition imaging, and better achieves the balance between a small total length and a large image plane of the lens. More specifically, 4.24 < TTL / IH < 4.48.

[0067] In some embodiments, the maximum field angle of view FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15° < FOV / Fno < 20°. Meeting the above range limits the optical lens to have an appropriate field angle of view and aperture value, can collect light at a large angle, and obtain good imaging quality. More specifically, 15.78° < FOV / Fno < 18.83°.

[0068] In some embodiments, the true image height IH corresponding to the maximum field angle of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 0.8 < IH / EPD < 1. Meeting the above range can increase the width of the light beam entering the optical lens, improve the brightness at the image plane of the optical lens, and avoid the generation of vignetting. More specifically, 0.86 < IH / EPD < 0.98.

[0069] 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 view of the optical lens, and the maximum field angle of view FOV of the optical lens satisfy: 6.5 < d1 / (IH / 2) / tan(FOV / 2) < 8.5. Meeting the above range can have a small front aperture while meeting the requirements of a large field angle of view and a large image plane of the optical lens. More specifically, 6.92 < d1 / (IH / 2) / tan(FOV / 2) < 7.87.

[0070] In some embodiments, the combined focal length f123 of the first lens, the second lens, and the third lens and the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: -37 < f123 / f4567 < -5.5. Meeting the above range is beneficial to balancing various aberrations of the system and improving the overall imaging quality by reasonably setting the focal length relationship of the lens groups before and after the aperture. More specifically, -33.93 < f123 / f4567 < -6.

[0071] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.3 < f1 / f < 5.5; the radius of curvature R1 of the object side surface of the first lens and the effective focal length f of the optical lens satisfy: 0.85 < R1 / f < 1.6; the radius of curvature R2 of the image side surface of the first lens and the effective focal length f of the optical lens satisfy: 2 < R2 / f < 5.8. Meeting the above ranges, by setting the first lens to have a positive refractive power and a suitable surface shape, it has the effect of converging light rays, reducing the height of peripheral light rays, and is beneficial to reducing the aperture of the rear lens. More specifically, 1.44 < f1 / f < 5.1; 0.91 < R1 / f < 1.48; 2.09 < R2 / f < 5.26.

[0072] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.7 < f3 / f < -0.6; the radius of curvature R5 of the object side surface of the third lens and the effective focal length f of the optical lens satisfy: -4 < R5 / f < -1.3; the radius of curvature R6 of the image side surface of the third lens and the effective focal length f of the optical lens satisfy: 0.4 < R6 / f < 3. Meeting the above ranges, the third lens has a negative optical power and a suitable surface shape, has the effect of diverging light rays, can disperse the central light rays and marginal light rays of each field of view, and can correct the aberration generated by the front lens. More specifically, -1.55 < f3 / f < - .62; -3.64 < R5 / f < -1.42; 0.45 < R6 / f < 2.69.

[0073] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.4 < f4 / f < .7; the radius of curvature R7 of the object side surface of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6 < R7 / f < 0.8; the radius of curvature R8 of the image side surface of the fourth lens and the effective focal length f of the optical lens satisfy: -0.65 < R8 / f < -0.3; the radius of curvature R7 of the object side surface of the fourth lens and the radius of curvature R8 of the image side surface of the fourth lens satisfy: 0 < (R7 + R8) / (R7 - R8) < 0.5. Meeting the above ranges, it is defined that the fourth lens has an appropriate positive optical power and surface shape, and the light rays are further converged. And gluing the fourth lens with a positive optical power and the fifth lens with a negative optical power is beneficial to making the light rays enter the rear lens smoothly, can adjust the optical path difference between different fields of view, and improve the resolution. More specifically, 0.47 < f4 / f < 0.61; 0.63 < R7 / f < 0.76; -0.6 < R8 / f < -0.35; 0.07 < (R7 + R) / R7 - R8) < 0.35.

[0074] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -2 < f5 / f < -0.9; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.65 < R9 / f < -0.3; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.2 < R10 / f < -0.6; the object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: -0.5 < (R9 - R10) / (R9 + R10) < -0.1. Meeting the above ranges and defining the fifth lens to have an appropriate negative optical power and surface shape can diverge the light rays emitted by the fourth lens, making the light rays in the marginal field of view show an upward trend, which is beneficial for the image points on the imaging surface to be away from the optical axis, so as to achieve the effect of matching with a large chip, obtain a larger picture, effectively eliminate aberration, and improve the resolution ability of the optical lens. More specifically, -1.84 < f5 / f < -0.99; -0.6 < R9 / f < -0.35; -1.08 < R10 / f < -0.68; -0.39 < (R9 - R10) / (R9 + R10) < -0.26.

[0075] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.9 < f7 / f < -0.5; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.1 < R13 / f < -0.4. Meeting the above ranges can effectively balance various aberrations generated by the front lens group, and at the same time is beneficial for increasing the divergence degree of light rays, increasing the area of light rays entering the imaging surface, achieving large-target-surface imaging of the lens, and improving the imaging quality of the optical lens. More specifically, -0.83 < f7 / f < -0.55; -1.03 < R13 / f < -0.42.

[0076] 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: 0.5 < IH / f < 0.6. Meeting the above ranges and controlling the image height and focal length of the optical lens within a reasonable range helps the optical lens to have the characteristic of a large image surface and improve the imaging quality. More specifically, 0.5 < IH / f < 0.56.

[0077] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.19 < BFL / f < 0.31. Meeting the above ranges defines that the optical lens has an appropriate back focus, which is convenient for reasonably arranging the positions of each lens and reduces the processing and assembly difficulty.

[0078] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis satisfy: 0.49 < ∑CT / TTL < 0.64. Meeting the above range can effectively compress the total length of the optical lens, and is beneficial to the structural design and production process of the optical lens.

[0079] In some embodiments, the sum ∑CT of the central thicknesses of the first lens to the seventh lens along the optical axis and the effective focal length f of the optical lens satisfy: 1.09 < ΣCT / f < 1.55. Meeting the above range can effectively correct the field curvature and distortion of the optical lens and improve the imaging quality of the optical lens.

[0080] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 2.5 < f2 / f < 38. Meeting the above range limits the second lens to have an appropriate positive optical power, further converges the light rays, and can share the positive optical power at the front end of the optical lens, thus facilitating avoiding excessive light ray deflection caused by overly concentrated optical power of the first lens and reducing the difficulty of aberration correction. More specifically, 2.82 < f2 / f < 34.68.

[0081] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 0.6 < f6 / f < 3.9; the radius of curvature R11 of the object side surface of the sixth lens and the effective focal length f of the optical lens satisfy: 0.7 < R11 / f < 1.6. Meeting the above range limits the sixth lens to have a positive optical power, which is beneficial to light ray convergence, enables the light ray trend to smoothly transition to the rear, reduces the height of the light rays incident on the rear, slows down the upward trend of the light rays, avoids the light energy loss caused by too large main light ray angle between the large field-of-view light rays and the chip when reaching the imaging surface, is beneficial to improving the illuminance of the edge field of view, and is beneficial to achieving a short total optical length. More specifically, 0.66 < f6 / f < 3.57; 0.77 < R,1 / f < 1.44.

[0082] In some embodiments, the optical lens satisfies the following conditional expressions: 12 mm < f < 17 mm; 7 mm < EPD < 10 mm; 33 mm < TTL < 35 mm; 1.6 < Fno < 2; 16° < CRA < 26°; 3 mm < BFL < 4.4 mm; 29° < FOV < 33°; 7 mm < IH < 8.5 mm. In the above conditional expressions, f represents the effective focal length of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the overall optical length of the optical lens, Fno represents the aperture value of the optical lens, CRA represents the chief ray angle of incidence of the optical lens, BFL represents the back focal length of the optical lens, FOV represents the maximum field angle of the optical lens, and IH represents the true image height corresponding to the maximum field angle of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as a large target surface, a large aperture, and a long focal length characteristic. More specifically, 13.88 mm < f < 15.58 mm; 7.78 mm < EPD < 9.17 mm; 33.7 mm < TTL < 34.1 mm; 1.69 < Fno < 1.91; 16.25° < CRA < 25.12°; 3.03 mm < BFL < 4.32 mm; 29.9° < FOV < 32.1°; 7.5 mm < IH < 8.1 mm.

[0083] In some embodiments, the lens material of the optical lens provided by the present invention may be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. Additionally, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The optical 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.

[0084] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens of the present invention adopt spherical lenses.

[0085] The present invention will be further described below with multiple embodiments. In each embodiment, the thickness, curvature radius, and material selection of each lens in the optical lens are somewhat different. For specific differences, refer to the parameter tables of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any other changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0086] Example 1

[0087] See also Figure 1 , shown is a schematic structural diagram of the optical lens 100 provided in Example 1 of the present invention. The optical lens 100 includes, in order from the object side to the imaging surface along the optical axis: a first lens L1, a second lens L2, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1, and a protective glass G2.

[0088] The first lens L1 has positive refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave;

[0089] The second lens L2 has positive refractive power, its object-side surface S3 is convex, and its image-side surface S4 is convex;

[0090] The third lens L3 has negative refractive power, its object-side surface S5 is concave, and its image-side surface S6 is concave;

[0091] The fourth lens L4 has positive refractive power, its object-side surface S7 is convex, and its image-side surface is convex;

[0092] The fifth lens L5 has negative refractive power, its object-side surface is concave, and its image-side surface S9 is convex;

[0093] The fourth lens L4 and the fifth lens L5 form a cemented lens group with positive refractive power. That is, the cemented surface between the image-side surface of the fourth lens L4 and the object-side surface of the fifth lens L5 is S8.

[0094] The sixth lens L6 has positive refractive power, its object-side surface S10 is convex, and its image-side surface S11 is concave;

[0095] The seventh lens L7 has negative refractive power, its object-side surface S12 is concave, and its image-side surface S13 is concave;

[0096] The object-side surface S14 and the image-side surface S15 of the filter G1 are both flat surfaces;

[0097] The object side surface S16 and the image side surface S17 of the protective glass G2 are both flat surfaces;

[0098] The imaging surface S18 is a plane.

[0099] The first lens L1 , the second lens L2 , the third lens L3 , the fourth lens L4 , the fifth lens L5 , the sixth lens L6 , and the seventh lens L7 are glass spherical lenses.

[0100] Table 1 shows the parameters of the lenses in the optical lens 100 in Example 1.

[0101] Table 1

[0102]

[0103] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 100 are shown as follows: Figure 2 、 Figure 3 、 Figure 4 shown.

[0104] Figure 2 The field curvature curves for Example 1 are shown, representing the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within a range of -0.01mm to 0.05mm, demonstrating that the optical lens is capable of effectively correcting field curvature.

[0105] Figure 3 The F-Tan (Theta) distortion curve for Example 1 shows the F-Tan (Theta) distortion of light of different wavelengths 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 angle (unit: °). As can be seen from the figure, the F-Tan (Theta) distortion of the optical lens is controlled within a range of -6% to 0, indicating that the optical lens is capable of correcting distortion well.

[0106] Figure 4 The MTF (Modulation Transfer Function) curve for Example 1 is shown. It represents the degree of lens imaging modulation at different spatial frequencies across the field of view. The horizontal axis represents spatial frequency (lp / mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF value of this example is consistently above 0.4 across the entire field of view. Within the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edges of the field of view, demonstrating excellent imaging quality and detail resolution at both low and high frequencies.

[0107] Example 2

[0108] See also Figure 5 , shown is a schematic structural diagram of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S11 of the sixth lens L6 is a convex surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

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

[0110] Table 2

[0111]

[0112] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 200 are shown as follows: Figure 6 、 Figure 7 、 Figure 8 As shown. Figure 6 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within 0~0.05mm, indicating that the optical lens can correct the field curvature well. Figure 7 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -5% to 0, indicating that the optical lens can correct the distortion well. Figure 8 As can be seen, the MTF value of this embodiment is above 0.38 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0113] Example 3

[0114] See also Figure 9 , shown is a schematic structural diagram of an optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, this embodiment has the following main differences: the image-side surface S4 of the second lens L2 is concave; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0115] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3.

[0116] Table 3

[0117]

[0118] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 300 are shown as follows: Figure 10 、 Figure 11 、 Figure 12 As shown. Figure 10 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.02mm~0.04mm, indicating that the optical lens can correct the field curvature well. Figure 11 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -6% to 0, indicating that the optical lens can correct the distortion well. Figure 12As can be seen, the MTF value of this embodiment is above 0.48 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0119] Example 4

[0120] See also Figure 13 , shown is a schematic structural diagram of an optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the object-side surface S3 of the second lens L2 is concave; the image-side surface S11 of the sixth lens L6 is convex; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0121] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4.

[0122] Table 4

[0123]

[0124] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 400 are shown as follows: Figure 14 、 Figure 15 、 Figure 16 As shown. Figure 14 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within 0~0.05mm, indicating that the optical lens can correct the field curvature well. Figure 15 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -4% to 0, indicating that the optical lens can correct the distortion well. Figure 16 As can be seen, the MTF value of this embodiment is above 0.3 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0125] Example 5

[0126] See also Figure 17 , shown is a schematic structural diagram of an optical lens 500 provided in Example 5 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the image-side surface S13 of the seventh lens L7 is a convex surface; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0127] Table 5 shows the relevant parameters of each lens in the optical lens 500 in Example 5.

[0128] Table 5

[0129]

[0130] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 500 are shown as follows: Figure 18 、 Figure 19 、 Figure 20 As shown. Figure 18 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within 0~0.05mm, indicating that the optical lens can correct the field curvature well. Figure 19 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -4% to 0, indicating that the optical lens can correct the distortion well. Figure 20 As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0131] Example 6

[0132] See also Figure 21 , shown is a schematic structural diagram of an optical lens 600 provided in Example 6 of the present invention. Compared with Example 1, this embodiment mainly differs in that: the image-side surface S4 of the second lens L2 is concave; the image-side surface S11 of the sixth lens L6 is convex; and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0133] The relevant parameters of each lens in the optical lens 600 in Example 6 are shown in Table 6.

[0134] Table 6

[0135]

[0136] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 600 are shown as follows: Figure 22 、 Figure 23 、 Figure 24 As shown. Figure 22 It can be seen that the field curvature of the meridional image plane and the sagittal image plane is controlled within -0.02mm~0.05mm, indicating that the optical lens can correct the field curvature well. Figure 23 It can be seen that the F-Tan (Theta) distortion of the optical lens is controlled within -4% to 0, indicating that the optical lens can correct the distortion well. Figure 24As can be seen, the MTF value of this embodiment is above 0.45 throughout the entire field of view. In the range of 0 to 120 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating good imaging quality and detail resolution at both low and high frequencies.

[0137] Please refer to Table 7, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value Fno, real image height IH corresponding to the maximum field of view angle, maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0138] Table 7

[0139]

[0140] In summary, the optical lens provided by the present invention uses seven lenses with specific optical powers. Through the combination of specific surface shapes and reasonable optical power distribution, it is possible to improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as long focus, large aperture, and high imaging quality.

[0141] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations 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 any one or more embodiments or examples.

[0142] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical lens, comprising seven lenses, 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 and whose image side is concave; A second lens with positive optical power; A third lens with negative optical power, whose object side is concave and whose image side is concave; A fourth lens with positive optical power, whose object side is convex and whose image side is convex; A fifth lens with negative optical power, whose object side is concave and whose image side is convex; A sixth lens with positive optical power, whose object side is convex; A seventh lens with negative optical power, whose object side is concave; Wherein, the curvature radius R1 of the object side of the first lens and the curvature radius R2 of the image side of the first lens satisfy: -0.8 < (R1 - R2) / (R1 + R2) < -0.1; the curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: |(R5 + R6) / (R5 - R6)| < 0.9; the maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15° < FOV / Fno < 20°.

2. The optical lens according to claim 1, wherein: The overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 2 < TTL / f < 2.5; 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: 4 < TTL / IH < 4.

8.

3. The optical lens according to claim 1, wherein: The maximum field angle FOV of the optical lens and the aperture value Fno of the optical lens satisfy: 15.78° < FOV / Fno < 18.83°; 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.

4. The optical lens according to claim 1, wherein: 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: 6.5 < d1 / (IH / 2) / tan(FOV / 2) < 8.5; the combined focal length f123 of the first lens, the second lens and the third lens and the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy: -37 < f123 / f4567 < -5.

5.

5. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.3 < f1 / f < 5.5; the curvature radius R1 of the object side of the first lens and the effective focal length f of the optical lens satisfy: 0.85 < R1 / f < 1.6; the curvature radius R2 of the image side of the second lens and the effective focal length f of the optical lens satisfy: 2 < R2 / f < 5.

8.

6. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -1.7 < f3 / f < -0.6; the curvature radius R5 of the object side of the third lens and the effective focal length f of the optical lens satisfy: -4 < R5 / f < -1.3; the curvature radius R6 of the image side of the third lens and the effective focal length f of the optical lens satisfy: 0.4 < R6 / f < 3.

7. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 0.4 < f4 / f < 0.7; the object-side curvature radius R7 of the fourth lens and the effective focal length f of the optical lens satisfy: 0.6 < R7 / f < 0.8; the image-side curvature radius R8 of the fourth lens and the effective focal length f of the optical lens satisfy: -0.65 < R8 / f < -0.

3.

8. The optical lens according to claim 1, wherein: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -2 < f5 / f < -0.9; the object-side curvature radius R9 of the fifth lens and the effective focal length f of the optical lens satisfy: -0.65 < R9 / f < -0.3; the image-side curvature radius R10 of the fifth lens and the effective focal length f of the optical lens satisfy: -1.2 < R10 / f < -0.

6.

9. The optical lens according to claim 1, wherein: The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -0.9 < f7 / f < -0.5; the object-side curvature radius R13 of the seventh lens and the effective focal length f of the optical lens satisfy: -1.1 < R13 / f < -0.

4.

10. The optical lens according to claim 1, wherein: The object-side curvature radius R9 of the fifth lens and the image-side curvature radius R10 of the fifth lens satisfy: -0.5 < (R9 - R10) / (R9 + R10) < -0.1; the object-side curvature radius R7 of the fourth lens and the image-side curvature radius R8 of the fourth lens satisfy: 0 < (R7 + R8) / (R7 - R8) < 0.5; the object-side curvature radius R1 of the first lens and the image-side curvature radius R2 of the first lens satisfy: -0.7 < (R1 - R2) / (R1 + R2) < -0.17; the object-side curvature radius R5 of the third lens and the image-side curvature radius R6 of the third lens satisfy: -0.31 < (R5 + R6) / (R5 - R6) < 0.77.

Images