Optical lens

Abstract

The invention provides an optical lens, which comprises seven lenses in total, and sequentially comprises a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with negative focal power and a sixth lens with negative focal power from an object side to an imaging surface, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a convex surface; the object side surface of the third lens is a concave surface, and the image side surface of the third lens is a convex surface; the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a convex surface, and the image side surface of the fifth lens is a convex surface; the object side surface of the sixth lens is a concave surface, and the image side surface of the sixth lens is a concave surface; and the object side surface of the seventh lens is a convex surface, and the image side surface of the seventh lens is a concave surface. According to the optical lens provided by the invention, the imaging quality of the optical lens can be improved, the aberration can be reduced, the imaging quality of the optical lens can be improved, and the lens has one or more advantages of large target surface, large aperture, high imaging quality and the like.

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 an important role in intelligent driving. They use various lenses and sensors to collect environmental information to ensure the driver's driving safety. In addition to requiring the optical lens to be thin and short and have high pixels and high resolution, the existing ADAS system lens also requires the optical lens to be able to image clearly under low illumination conditions. Therefore, it is necessary to develop an optical lens with good imaging effect. 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 by the present invention is:

[0006] An optical lens, comprising seven lenses, which include:

[0007] The first lens has a negative optical power, and its object side surface is concave and its image side surface is concave;

[0008] The second lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0009] The third lens has a negative optical power, its object side surface is concave, and its image side surface is convex;

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

[0011] a fifth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex;

[0012] a sixth lens having negative optical power, whose object-side surface is concave and whose image-side surface is concave;

[0013] The seventh lens has positive refractive power, its object side surface is convex, and its image side surface is concave;

[0014] Among them, the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: 1.2 < (R1 - R2) / (R1 + R2) < 1.5; the curvature radius R7 of the object side surface of the fourth lens and the curvature radius R8 of the image side surface of the fourth lens satisfy: 0.8 < (R7 - R8) / (R7 + R8) < 0.95.

[0015] Further preferably, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 6.

[0016] Further preferably, the effective focal length f of the optical lens, the maximum field of view angle FOV of the optical lens, and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.82 < (IH / 2) / (f × tan(FOV / 2)) < 0.9.

[0017] Further preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 2.1.

[0018] Further preferably, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1 < IH / f < 1.2.

[0019] Further preferably, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.4 < BFL / f < 0.6.

[0020] Further preferably, the effective focal length f of the optical lens, the radian value θ of the maximum half field of view angle of the optical lens, and the clear aperture semi-diameter d1 of the object side surface of the first lens satisfy: 0.6 < f × θ / d1 < 0.7.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.6 < f1 / f < -1.5; the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -0.7 < f1 / f2 < -0.6.

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.5 < f7 / f < 1.7.

[0023] Further preferably, the curvature radius R1 of the object side surface of the first lens and the sagittal height Sag1 of the clear aperture of the object side surface of the first lens satisfy: 77 < R1 / Sag1 < 166.

[0024] The optical lens provided by the present invention adopts seven lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, the imaging quality of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved, so that the lens has one or more advantages such as a large target surface, a 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 easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0026] Figure 1 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

[0027] Figure 2 Graph showing the field curvature of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 1 of the present invention.

[0029] Figure 4 This is the MTF curve diagram of the optical lens in Example 1 of the present invention.

[0030] Figure 5 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0031] Figure 6 4 is a field curvature curve diagram of the optical lens in Example 2 of the present invention.

[0032] Figure 7 Graph showing the F-Tan (Theta) distortion 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] Fig. 9 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

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

[0036] Fig.11 Graph showing the F-Tan (Theta) distortion of the optical lens in Example 3 of the present invention.

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

[0038] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0039] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0040] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0041] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0042] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0043] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0044] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0045] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0046] The optical lens provided by the embodiment of the present invention comprises seven lenses in total, which are, along the optical axis, from the object side to the imaging surface, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in order.

[0047] In some embodiments, the first lens may have a negative optical power, its object side surface is concave, and its image side surface is concave. The second lens may have a positive optical power, its object side surface is convex, and its image side surface is convex. The third lens may have a negative optical power, its object side surface is concave, and its image side surface is convex. The fourth lens may have a positive optical power, its object side surface is concave, and its image side surface is convex. The fifth lens may have a positive optical power, its object side surface is convex, and its image side surface is convex. The sixth lens may have a negative optical power, its object side surface is concave, and its image side surface is concave. The seventh lens may have a positive optical power, its object side surface is convex, and its image side surface is concave.

[0048] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the third lens and the fourth lens. It is understood that the aperture is used to limit the amount of light entering to change the brightness of the image. When the aperture is located between the third lens and the fourth lens, it is convenient to correct the aperture aberration.

[0049] In some embodiments, the optical lens may further include a filter, and the filter and the protective glass are sequentially arranged between the seventh lens and the imaging surface along the optical axis. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the impact resistance and scratch resistance of the optical lens, while having almost no effect on the imaging quality of the optical lens.

[0050] In some embodiments, the fifth lens and the sixth lens can be glued to form a glued lens, which can effectively correct the chromatic aberration of the optical lens, reduce the eccentricity sensitivity of the optical lens, balance the aberration of the optical lens, and improve the imaging quality of the optical lens; it can also reduce the assembly sensitivity of the optical lens, thereby reducing the difficulty of the processing technology of the optical lens and improving the assembly yield of the optical lens.

[0051] In some embodiments, the radius of curvature R1 of the object side surface of the first lens and the radius of curvature R2 of the image side surface of the first lens satisfy: 1.2 < (R1 - R2) / (R1 + R2) < 1.5. Meeting the above range can make the collected light enter the rear optical system in a divergent form as much as possible, while effectively reducing the angle between the light incident on the edge field of view and the object side surface of the first lens, and improving the overall relative illumination of the edge of the lens.

[0052] In some embodiments, 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: 0.8 < (R7 - R8) / (R7 + R8) < 0.95. Meeting the above range can assist the light trend to be gentle. The convex image side surface can converge the light and reduce the overall optical length.

[0053] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 6. Meeting the above range is beneficial to miniaturize the entire lens and achieve long focal length.

[0054] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 0.82 < (IH / 2) / (f × tan(FOV / 2)) < 0.9. Meeting the above range can control the optical lens to have less distortion and improve the imaging quality of the optical lens.

[0055] In some embodiments, the true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 2.1. Meeting the above range is beneficial to increase the light passing amount and make the brightness of the peripheral field of view and the central field of view more uniform.

[0056] In some embodiments, the true image height IH corresponding to the maximum field of view of the optical lens and the effective focal length f of the optical lens satisfy: 1 < IH / f < 1.2. Meeting the above range can control the image height and focal length of the optical lens within a reasonable range, which helps the optical lens to have the characteristic of a large image plane and improve the imaging quality.

[0057] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.4 < BFL / f < 0.6. Meeting the above range limits the optical lens to have an appropriate back focus, which is convenient for reasonably arranging the positions of each lens and reduces the processing and assembly difficulty.

[0058] 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: 0.85 < ∑CT / TTL < 0.95. Satisfying the above range and reasonably configuring the total optical length of the optical lens and the sum of the thicknesses of each lens helps to achieve high pixel characteristics and improve the imaging quality of the optical lens.

[0059] In some embodiments, the effective focal length f of the optical lens, the radian value θ of the maximum half field of view angle of the optical lens, and the half clear aperture d1 of the object side surface of the first lens satisfy: 0.6 < f×θ / d1 < 0.7. Satisfying the above range and controlling the focal length of the optical lens, the radian value corresponding to the maximum half field of view angle of the lens, and the front aperture of the lens can achieve the balance of the focal length, field of view, and aperture of the lens.

[0060] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.6 < f1 / f < -1.5. Satisfying the above range enables the first lens to have a negative optical power and can diverge the light passing through it, which is beneficial for achieving a small front aperture.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 2 < f2 / f < 3. Satisfying the above range limits the second lens to have an appropriate positive optical power and has the effect of converging light. When combined with the negative optical power of the first lens, it can further converge the light passing through the first lens, reduce the height of peripheral light, which is beneficial for reducing the aperture of the rear lens, and at the same time is beneficial for balancing aberrations and improving resolution.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: f3 / f < -540. Satisfying the above range has the effect of diverging light, which can disperse the central light and edge light of each field of view, enabling the rear optical system to have a larger light receiving surface to receive the light emerging from the image side surface of the third lens, achieving a larger light input, and being beneficial for increasing the relative illumination.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 3 < f4 / f < 4. Satisfying the above range is beneficial for the convergence of light, enabling the diverging light to smoothly enter the rear optical system and better achieving high-quality imaging of the lens; at the same time, it can effectively correct the distortion of the edge field of view, reduce the deformation degree of the edge of the captured image, and improve the image quality.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 1.6 < f5 / f < 1.75. Satisfying the above range defines that the fifth lens has an appropriate positive optical power, which is beneficial to the convergence of light rays. And by combining the fifth lens with a positive optical power and the sixth lens with a negative optical power, the optical path difference between different fields of view can be adjusted, the resolution can be improved, it is beneficial for the light rays to enter the rear lens smoothly, and further the field curvature can be reduced and the off-axis aberration of the optical lens can be corrected.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -1 < f6 / f < -0.9. Satisfying the above range defines that the sixth lens has an appropriate negative optical power, which can diverge the light rays emitted by the fifth lens, making the light rays in the edge 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 be beneficial 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.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.5 < f7 / f < 1.7. Satisfying the above range defines that the seventh lens has a positive optical power, which is beneficial to the convergence of light rays, makes the light ray trend transition smoothly 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 the too large main ray angle between the light rays in the large field of view 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 overall optical length.

[0067] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -0.7 < f1 / f2 < -0.6. Satisfying the above range controls the optical powers of the first lens and the second lens to be one positive and one negative, which is beneficial to balancing aberration and improving resolution; further, controlling the ratio of the two within the conditional range is beneficial to the smooth trend of light rays and reduces sensitivity.

[0068] In some embodiments, the curvature radius R1 of the object side surface of the first lens and the sagittal height Sag1 of the clear aperture radius of the object side surface of the first lens satisfy: 77 < R1 / Sag1 < 166. Satisfying the above range controls the ratio of the sagittal height of the clear aperture of the object side surface to the curvature radius, which is beneficial to reducing the angle between the light rays in the edge field of view and the object side surface of the first lens when incident, and improving the relative edge illuminance of the overall lens.

[0069] In some embodiments, the air gap CT34 between the third lens and the fourth lens on the optical axis and the total optical length TTL of the optical lens satisfy: 0.15 < CT34 / TTL < 0.25. Meeting the above range and controlling the air gap between the third lens and the fourth lens is beneficial to the gentle transition of light on the premise of miniaturization and improve the imaging quality; further, when the air gap is controlled to be relatively large, the sensitivity of the optical lens can be further reduced.

[0070] In some embodiments, the optical lens satisfies the following conditional expressions: 7mm < f < 8mm; 60° < FOV < 75°; 4mm < EPD < 5mm; 38mm < TTL < 41mm; 1.5 < Fno < 1.8; 8mm < IH < 9mm; 25° < CRA < 30°; 3mm < BFL < 4mm. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, EPD represents the entrance pupil diameter of the optical lens, TTL represents the total optical length of the optical lens, Fno represents the aperture value of the optical lens, IH represents the true image height corresponding to the maximum field of view angle of the optical lens, CRA represents the chief ray incident angle at the maximum image height of the optical lens, and BFL represents the back focal length of the optical lens. Meeting the above range, 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.

[0071] 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 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.

[0072] 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, and the sixth lens of the present invention adopt spherical lenses, and the seventh lens adopts an aspherical lens.

[0073] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0074]

[0075] Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, and F are the fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

[0076] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0077] Example 1

[0078] See also Figure 1 , shown is a schematic diagram of the structure of the optical lens 100 provided in Example 1 of the present invention, and the optical lens 100 includes, 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 and a filter G1.

[0079] The first lens L1 has negative refractive power, its object side surface S1 is concave, and its image side surface S2 is concave;

[0080] The second lens L2 has positive refractive power, its object-side surface S3 is convex, and its image-side surface S4 is convex;

[0081] The third lens L3 has negative refractive power, its object-side surface S5 is concave, and its image-side surface S6 is convex;

[0082] The fourth lens L4 has positive refractive power, its object-side surface S7 is concave, and its image-side surface S8 is convex;

[0083] The fifth lens L5 has positive refractive power, its object-side surface S9 is convex, and its image-side surface S10 is convex;

[0084] The sixth lens L6 has negative refractive power, its object-side surface S10 is concave, and its image-side surface S11 is concave;

[0085] The fifth lens L5 and the sixth lens L6 form a cemented lens group, that is, the cemented surface between the image side surface of the fifth lens L5 and the object side surface of the sixth lens L6 is S10;

[0086] The seventh lens L7 has positive refractive power, its object-side surface S12 is convex, and its image-side surface S13 is concave;

[0087] The object side surface S14 and the image side surface S15 of the filter G1 are both planes;

[0088] The object side surface S16 and the image side surface S17 of the protective glass G2 are both flat surfaces;

[0089] The imaging surface S18 is a plane.

[0090] The seventh lens L7 is a glass aspherical lens, and 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.

[0091] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0092] Table 1-1

[0093]

[0094]

[0095] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0096] Table 1-2

[0097] Face number K B C D E F S12 -1.82E+00 8.14E-04 5.14E-06 -7.75E-08 5.38E-09 1.23E-10 S13 1.76E+00 8.82E-04 5.75E-06 5.44E-06 -4.42E-07 1.96E-08

[0098] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 shown.

[0099] Figure 2 The field curvature curve of Example 1 is shown, which indicates the degree of curvature of light of different wavelengths on the meridional image plane and the sagittal image plane, with the horizontal axis indicating the offset (unit: mm) and the vertical axis indicating the half field angle (unit: °). It can be seen from the figure that the field curvature of the meridional image plane and the sagittal image plane is controlled within ±0.02 mm, indicating that the optical lens can correct the field curvature well.

[0100] Figure 3 The F-Tan (Theta) distortion curve of Example 1 is shown, which represents the distortion of light of different wavelengths at different image heights on the imaging surface, with the horizontal axis representing the distortion value (unit: %) and the vertical axis representing the half field angle (unit: °). It can be seen from the figure that the distortion of the optical lens is controlled within -15% to 0, indicating that the optical lens can correct the distortion well.

[0101] Figure 4The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of this embodiment is above 0.6 in the whole field of view, and 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, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency conditions.

[0102] Example 2

[0103] See also Figure 5 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0104] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0105] Table 2-1

[0106]

[0107] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0108] Table 2-2

[0109] Face number K B C D E F S12 -1.84E+00 8.13E-04 5.25E-06 -8.44E-08 5.10E-09 1.94E-10 S13 1.35E+00 8.68E-04 3.95E-06 5.30E-06 -4.45E-07 2.01E-08

[0110] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 200 are respectively as follows: Figure 6 , Figure 7 , Figure 8 shown.

[0111] from Figure 6 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.02mm, indicating that the optical lens can correct the field curvature well.

[0112] from Figure 7 It can be seen that the distortion of the optical lens is controlled within -17% to 0, which means that the optical lens can correct the distortion well.

[0113] from Figure 8 It can be seen that the MTF value of this embodiment is above 0.6 in the whole 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, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0114] Example 3

[0115] See also Fig. 9 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0116] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0117] Table 3-1

[0118]

[0119]

[0120] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0121] Table 3-2

[0122] Face number K B C D E F S12 -1.08E+00 3.90E-04 6.48E-06 -2.09E-08 -1.07E-09 1.77E-10 S13 1.20E+01 4.77E-04 -1.07E-05 4.71E-06 -3.75E-07 1.34E-08

[0123] In this embodiment, the field curvature curve, F-Tan (Theta) distortion curve, and MTF curve of the optical lens 300 are respectively as follows: Fig.10 , Fig.11 , Fig.12 shown.

[0124] from Fig.10 It can be seen that the field curvature of the meridian image plane and the sagittal image plane is controlled within ±0.02mm, indicating that the optical lens can correct the field curvature well.

[0125] from Fig.11 It can be seen that the distortion of the optical lens is controlled within -15% to 0, which means that the optical lens can correct the distortion well.

[0126] from Fig.12 It can be seen that the MTF value of this embodiment is above 0.6 in the whole 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, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0127] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the real image height IH corresponding to the maximum field of view angle, the chief ray incident angle CRA at the maximum image height, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0128] Table 4

[0129]

[0130]

[0131] In summary of the above embodiments, the optical lens provided by the present invention adopts seven lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it is possible to improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens, so that the lens has one or more advantages such as a large target surface, a large aperture, and high imaging quality.

[0132] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0133] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, 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 a negative optical power, whose object side is concave and whose image side is concave; A second lens with a positive optical power, whose object side is convex and whose image side is convex; A third lens with a negative optical power, whose object side is concave and whose image side is convex; A fourth lens with a positive optical power, whose object side is concave and whose image side is convex; A fifth lens with a positive optical power, whose object side is convex and whose image side is convex; A sixth lens with a negative optical power, whose object side is concave and whose image side is concave; A seventh lens with a positive optical power, whose object side is convex and whose image 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: 1.2 < (R1 - R2) / (R1 + R2) < 1.5; the curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: 0.8 < (R7 - R8) / (R7 + R8) < 0.

95.

2. The optical lens according to claim 1, characterized in that: The overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 5 < TTL / f < 6.

3. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens, the maximum field of view angle FOV of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 0.82 < (IH / 2) / (f × tan(FOV / 2)) < 0.

9.

4. The optical lens according to claim 1, characterized in that: The true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 2.

1.

5. The optical lens according to claim 1, characterized in that: The true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1 < IH / f < 1.

2.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the back focal length BFL of the optical lens satisfy: 0.4 < BFL / f < 0.

6.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens, the radian value θ of the maximum half field of view angle of the optical lens and the clear aperture semi-diameter d1 of the object side of the first lens satisfy: 0.6 < f × θ / d1 < 0.

7.

8. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.6 < f1 / f < -1.5; the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -0.7 < f1 / f2 < -0.

6.

9. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 1.5 < f7 / f < 1.

7.

10. The optical lens according to claim 1, characterized in that: The curvature radius R1 of the object side of the first lens and the sagittal height Sag1 of the clear aperture semi-diameter of the object side of the first lens satisfy: 77 < R1 / Sag1 < 166.

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