Optical lens

Abstract

The present invention discloses an optical lens, which includes, from the object side to the imaging surface along the optical axis, a first lens with negative optical power; a second lens with negative optical power; a third lens with positive optical power; a fourth lens with negative optical power; a fifth lens with positive optical power; a sixth lens with positive optical power; a seventh lens with negative optical power; and an eighth lens with positive optical power. The present invention adopts eight lenses, and through specific surface shape settings and reasonable optical power distribution, especially the first and second lenses adopt negative optical power, the optical lens can collect a wide range of light and improve the field of view of the optical lens. At the same time, by setting the optical lens to have a large positive distortion, the marginal field of view ratio can be effectively increased, and the angular resolution of the marginal field of view can be improved.

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. The existing ADAS system's side view lenses need to be equipped with multiple lenses on both sides of the vehicle body to achieve perspective fusion, and the image quality is poor at the edge of the field of view, and obstacles cannot be clearly distinguished. Summary of the invention

[0004] To this end, an object of the present invention is to provide an optical lens having at least the advantages of a large field of view angle and good imaging effect of the edge field of view.

[0005] The present invention provides an optical lens, which comprises, in order from the object side to the imaging surface along the optical axis: a first lens with negative optical power, whose object side surface is convex and whose image side surface is concave; a second lens with negative optical power, whose object side surface is concave and whose image side surface is concave; a third lens with positive optical power, whose object side surface is convex and whose image side surface is convex; a fourth lens with negative optical power, whose object side surface is concave and whose image side surface is concave; a fifth lens with positive optical power, whose object side surface is convex and whose image side surface is convex; a sixth lens with positive optical power, whose object side surface is convex and whose image side surface is convex; a seventh lens with negative optical power, whose object side surface is concave and whose image side surface is concave; and an eighth lens with positive optical power, whose object side surface is concave and whose image side surface is convex.

[0006] In some embodiments, the maximum field of view FOV of the optical lens satisfies: 190°<FOV.

[0007] In some embodiments, the incident angle CRA of the principal ray with the maximum field angle of the optical lens on the image plane satisfies: 1°<CRA<15°.

[0008] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 16.0<TTL / f<23.0.

[0009] In some embodiments, the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 4.00<TTL / IH<4.80.

[0010] In some embodiments, the image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the arc value θ of the maximum half field angle of the optical lens satisfy: 1.15<(IH / 2) / (f×θ). Preferably, the image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the arc value θ of the maximum half field angle of the optical lens satisfy: 1.19≤(IH / 2) / (f×θ)<1.30.

[0011] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 90°<FOV / FNO<110°.

[0012] In some embodiments, the image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 4.0<IH / f.

[0013] In some embodiments, the optical back focus BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.0<BFL / f.

[0014] In some embodiments, the effective focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: f1 / f<-10.0.

[0015] In some embodiments, the effective focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: f2 / f<-5.5.

[0016] In some embodiments, the effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 3.3<f3 / f.

[0017] In some embodiments, the effective focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -2.0<f4 / f<-1.6.

[0018] In some embodiments, the effective focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 2.0<f5 / f<2.5.

[0019] In some embodiments, the effective focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 3.5<f6 / f<6.5.

[0020] In some embodiments, the effective focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -6.5<f7 / f<-4.5.

[0021] In some embodiments, the effective focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.6<f8 / f<2.0.

[0022] In some embodiments, a radius of curvature R3 of the object side surface of the second lens and a radius of curvature R4 of the image side surface of the second lens satisfy: 1.2<(R3-R4) / (R3+R4).

[0023] In some embodiments, a radius of curvature R15 of the object side surface of the eighth lens and a radius of curvature R16 of the image side surface satisfy: 0.2<(R15-R16) / (R15+R16)<0.6.

[0024] In some embodiments, the total optical length TTL of the optical lens and the sum ΣCT of the center thicknesses of the first lens to the eighth lens along the optical axis respectively satisfy: 0.28<ΣCT / TTL<0.45.

[0025] In some embodiments, an air gap CT23 between the image side surface of the second lens and the object side surface of the third lens on the optical axis and a total optical length TTL of the optical lens satisfy: 0.28<CT23 / TTL<0.40.

[0026] Compared with the prior art, the optical lens provided by the present invention adopts eight lenses with optical focal length. Through specific surface shape setting and reasonable optical focal length distribution, especially the first lens and the second lens adopt negative optical focal length, the optical lens can collect as much light as possible in a wide range, improve the field of view and relative illumination of the optical lens, and at the same time, by setting the optical lens to have a large positive distortion, it can effectively increase the proportion of the edge field of view in the entire image plane, and improve the angular resolution of the edge field of view, so that the optical lens can better meet the use requirements of vehicle-mounted lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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:

[0028] Figure 1 Schematic diagram of the structure of the optical lens of Example 1 of the present invention.

[0029] Figure 2 4 is a F-θ distortion curve diagram of the optical lens in Example 1 of the present invention.

[0030] Figure 3 This is the MTF curve diagram of the optical lens in Example 1 of the present invention.

[0031] Figure 4 Schematic diagram of the structure of the optical lens of embodiment 2 of the present invention.

[0032] Figure 5 4 is an F-θ distortion curve diagram of the optical lens in Example 2 of the present invention.

[0033] Figure 6This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0034] Figure 7 Schematic diagram of the structure of the optical lens of Example 3 of the present invention.

[0035] Figure 8 4 is a F-θ distortion curve diagram of the optical lens in Example 3 of the present invention.

[0036] Fig. 9 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0037] Fig.10 Schematic diagram of the structure of the optical lens of Example 4 of the present invention.

[0038] Fig.11 4 is an F-θ distortion curve diagram of the optical lens in Example 4 of the present invention.

[0039] Fig.12 This is the MTF curve diagram of the optical lens in Example 4 of the present invention.

[0040] Fig.13 Schematic diagram of the structure of the optical lens of Example 5 of the present invention.

[0041] Fig.14 4 is a F-θ distortion curve diagram of the optical lens in Example 5 of the present invention.

[0042] Fig.15 This is the MTF curve diagram of the optical lens in Example 5 of the present invention. DETAILED DESCRIPTION

[0043] In order to better understand the present invention, a more detailed description will be made of various aspects of the present invention with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of embodiments of the present invention, and are not intended to limit the scope of the present invention 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 invention, "may" is used to mean "one or more embodiments of the present invention". And, the term "exemplary" is intended to refer to an example or illustration.

[0048] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which the present invention 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 explicitly defined in this article.

[0049] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0050] The present invention provides an optical lens, which includes, 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, a seventh lens and an eighth lens.

[0051] In some embodiments, the first lens is configured to have negative optical focal length, with its object side being convex and its image side being concave, so as to obtain as much incident light at a large angle as possible, thereby expanding the field of view of the optical lens, and at the same time slowing down the turning trend of light, reducing the difficulty of aberration correction of subsequent lenses, and improving the imaging quality of the optical lens.

[0052] In some embodiments, the second lens is configured to have a negative optical focal length, with a concave object side and a concave image side, so that it can receive light passing through the first lens and can make the light emission smooth, which is beneficial to improving aberrations; at the same time, it can make the light entering the second lens have an obvious light turning point, change the trend of large-angle light, and can quickly diverge the large-angle light passing through the object side of the second lens, which is beneficial to the rear lens to correct the aberration of large-angle light, thereby improving the imaging quality of the optical lens.

[0053] In some embodiments, the third lens is configured to have positive optical power, with its object side surface being convex and its image side surface being convex, which can further converge the light and, when combined with the second lens having negative optical power, allow the light to smoothly transition to the rear lens after passing through the third lens.

[0054] In some embodiments, the fourth lens is configured to have negative optical power, with its object side surface being concave and its image side surface being concave, so that it can receive and diverge the front light. The light of the edge field of view will have a longer optical path than the light of the center field of view after passing through the fourth lens, thereby changing the light trend of the edge field of view, facilitating defocus correction of the edge field of view aberrations, and improving the imaging quality of the optical lens.

[0055] In some embodiments, the fifth lens is configured to have positive optical power, with its object side surface being convex and its image side surface being convex, which can compress the angle of the incident light to achieve a smooth transition of the light, allowing the divergent light to smoothly enter the rear, further allowing the light trend to transition smoothly, which is beneficial to reducing the aperture of the rear end lens.

[0056] In some embodiments, the sixth lens is configured to have positive optical power, with its object side surface being convex and its image side surface being convex, which can produce a converging effect on light and, when combined with the seventh lens having negative optical power, enhance the correction effect on chromatic aberration, play a role in correcting field curvature, and improve the imaging quality of the optical lens.

[0057] In some embodiments, the seventh lens is configured to have negative optical power, with its object side surface being concave and its image side surface being concave, so that subsequent lenses can have a larger light receiving surface, thereby improving optical performance, and can effectively correct various aberrations caused by the front positive lens, thereby improving the imaging quality of the optical lens.

[0058] In some embodiments, the eighth lens is configured to have positive optical power, with its object side being concave and its image side being convex, which can avoid reflection from the rear end chip or protective glass, thereby reducing the energy of ghost images on the imaging screen and reducing interference effects, while converging the light, which is beneficial to reducing the rear port diameter of the optical lens.

[0059] In some embodiments, the sixth lens and the seventh lens form a cemented lens, which can reduce the light loss caused by reflection between lenses and improve the relative illumination of each field of view; it can enhance the correction effect of chromatic aberration and improve the overall imaging quality of the optical lens.

[0060] In some embodiments, the aperture may be disposed between the third lens and the fourth lens, and the third lens or the fourth lens has the smallest aperture among all the lenses. In the process of gradually decreasing aperture from the object side to the aperture surface, the light is gradually converged and limited, which helps to reduce stray light and unwanted reflections, thereby improving the clarity and contrast of the image; after the aperture surface, the aperture gradually increases, which helps to ensure that more light can reach the imaging surface, thereby improving the brightness and signal-to-noise ratio of the image; and it can also balance the structure and focal length distribution of the front lens group and the rear lens group.

[0061] In some embodiments, the optical lens may further include a filter, which is disposed between the eighth lens and the imaging surface to filter out interference light and prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0062] In some embodiments, the maximum field of view FOV of the optical lens satisfies: 190°<FOV. Meeting the above range is conducive to achieving wide-angle characteristics, thereby being able to obtain more scene information and meet the needs of large-scale detection.

[0063] In some embodiments, the incident angle CRA of the principal ray of the maximum field angle of the optical lens on the image plane satisfies: 1°<CRA<15°. Meeting the above range can make the CRA of the optical lens and the CRA of the chip photosensitive element have a larger allowable error range, thereby improving the adaptability of the optical lens to the image sensor.

[0064] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 16.0<TTL / f<23.0. Meeting the above range can ensure that there is enough space to adjust the lens structure and optimize the imaging effect of the optical lens.

[0065] In some embodiments, the total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle of the optical lens satisfy: 4.00<TTL / IH<4.80. Meeting the above range can effectively balance the requirements of the image height and the total optical length of the optical lens.

[0066] In some embodiments, the image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field of view of the optical lens satisfy: 1.15<(IH / 2) / (f×θ). Meeting the above range can achieve a larger positive F-θ distortion, which is beneficial to achieving the ultra-wide-angle characteristics of the optical lens, and at the same time can effectively increase the proportion of the edge field of view of the optical lens in the entire image plane, and improve the angular resolution of the edge field of view. Preferably, the image height IH corresponding to the maximum field of view of the optical lens, the effective focal length f of the optical lens, and the radian value θ of the maximum half field of view of the optical lens satisfy: 1.19≤(IH / 2) / (f×θ)<1.30.

[0067] In some embodiments, the maximum field of view FOV of the optical lens and the aperture value FNO of the optical lens satisfy: 90°<FOV / FNO<110°. Meeting the above range can match field of view angles of different sizes, thereby better balancing the relationship between the field of view angle and the aperture size of the optical lens.

[0068] In some embodiments, the image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy: 4.0<IH / f. Meeting the above range can ensure matching of a chip with a large image plane, so that the optical lens has the characteristics of a large field angle and a large image plane.

[0069] In some embodiments, the optical back focus BFL of the optical lens and the effective focal length f of the optical lens satisfy: 1.0<BFL / f. Meeting the above range can achieve a balance between good imaging quality and easy-to-assemble optical back focus length, which is beneficial to ensure the imaging quality of the optical lens while avoiding interference between the lens and other components, reducing the difficulty of the camera module assembly process, and improving the production yield.

[0070] In some embodiments, the effective focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: f1 / f<-10.0. Meeting the above range not only allows a wide viewing angle of light to enter the optical lens to achieve ultra-wide angle characteristics, but also uses a larger negative focal length to help control perspective distortion and reduce field curvature, thereby improving the geometric accuracy of the imaging surface.

[0071] In some embodiments, the effective focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: f2 / f<-5.5. If the above range is met, a part of the negative focal length of the first lens can be shared, which helps to make the light with a large field angle enter the optical lens smoothly, so as to expand the light collection range of the optical lens.

[0072] In some embodiments, the effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 3.3<f3 / f. When the above range is met, the light deflection angle can be reduced while converging the light, so that the light trend can transition smoothly, and at the same time, various aberrations generated by the front lens can be balanced, thereby improving the imaging quality of the optical lens.

[0073] In some embodiments, the effective focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -2.0<f4 / f<-1.6. Meeting the above range can diverge light, so that the subsequent lens has a larger light receiving surface, improve optical performance, and effectively correct various aberrations caused by the front positive lens, thereby improving the imaging quality of the optical lens.

[0074] In some embodiments, the effective focal length f5 of the fifth lens satisfies the effective focal length f of the optical lens: 2.0<f5 / f<2.5. When the above range is met, the light emitted from the fourth lens can be converged and adjusted to slow down the turning trend and convergence degree of the light, so that the light transitions smoothly, and at the same time, various aberrations generated by the front lens can be balanced to improve the overall imaging quality of the optical lens.

[0075] In some embodiments, the effective focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: 3.5<f6 / f<6.5. When the above range is met, the light can be converged, and in combination with the negative lens of the seventh lens, the aberration can be further reduced, and at the same time, the light can be effectively and smoothly converged at the end, so that the light can reach the imaging surface smoothly.

[0076] In some embodiments, the effective focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: -6.5<f7 / f<-4.5. Meeting the above range can diverge light, which is conducive to slowing down the trend of light at the rear end of the lens, achieving a long back focus BFL, and can disperse the central light and edge light of each field of view, increase the relative illumination of the optical lens, and at the same time facilitate the correction of the aberration of the edge light and the central light to achieve high resolution. At the same time, the angle from the light to the image plane can meet the CRA requirements, achieve a small CRA, and improve the resolution and illumination.

[0077] In some embodiments, the effective focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: 1.6<f8 / f<2.0. When the above range is met, the light can be quickly converged to the imaging surface, the upward trend of the light is slowed down, and the light energy loss caused by the large angle between the light of the large field of view and the main light of the chip when reaching the image surface is avoided, which is conducive to improving the illumination of the edge field of view.

[0078] In some embodiments, the radius of curvature R3 of the object side of the second lens and the radius of curvature R4 of the image side satisfy: 1.2<(R3-R4) / (R3+R4). Meeting the above range can make the object side of the second lens relatively flat, and the image side relatively curved, and when the light passes through the second lens, it is first quickly deflected and then smoothly transitioned, and at the same time, the light with different incident angles is separated, and the exit height of the large-angle light is reduced, so as to achieve positive distortion.

[0079] In some embodiments, the radius of curvature R15 of the object side of the eighth lens and the radius of curvature R16 of the image side satisfy: 0.2<(R15-R16) / (R15+R16)<0.6. Meeting the above range can make the object side of the eighth lens relatively flat, and the light first transitions smoothly and then deflects quickly when passing through the eighth lens, avoiding the loss of light energy caused by the large angle between the main light of the chip and the large field of view when the light reaches the image plane, and can ensure that the optical lens has a large positive distortion.

[0080] In some embodiments, the total optical length TTL of the optical lens and the sum of the center thicknesses of the first to eighth lenses along the optical axis ΣCT satisfy: 0.28<ΣCT / TTL<0.45. If the above range is met, the total length of the optical lens can be compressed, making the structure of the optical lens more compact.

[0081] In some embodiments, the air interval CT23 between the image side surface of the second lens and the object side surface of the third lens on the optical axis and the total optical length TTL of the optical lens satisfy: 0.28<CT23 / TTL<0.40. Meeting the above range is conducive to the smooth transition of light passing through the second lens, the light smoothly enters the rear lens, and the imaging quality of the optical lens is improved.

[0082] As an implementation mode, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens can be made of all-glass lenses or a glass-plastic mixture, both of which can achieve good imaging effects. In the present application, in order to improve the imaging quality of the lens, each lens uses a glass lens. At the same time, at least one of the object side or image side of the fourth lens, the fifth lens and the eighth lens is an aspherical surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic and has the advantages of improving distortion aberration and improving astigmatism aberration.

[0083] In order to make the system have better optical performance, multiple aspherical lenses are used in the lens, and the shape of each aspherical surface of the optical lens satisfies the following equation:

[0084] ;

[0085] 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, A, B, C, D, E, F, and G are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, and fourteenth-order surface coefficients respectively.

[0086] 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.

[0087] Example 1

[0088] See also Figure 1 , which is a schematic diagram of the structure of the optical lens provided in Embodiment 1 of the present invention, wherein the optical lens includes, in sequence from the object side to the imaging surface S18 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, an eighth lens L8 and a filter G1.

[0089] Among them, the first lens L1 is a spherical lens with negative optical power, the object side surface S1 of the first lens is convex, and the image side surface S2 of the first lens is concave; the second lens L2 is a spherical lens with negative optical power, the object side surface S3 of the second lens is concave, and the image side surface S4 of the second lens is concave; the third lens L3 is a spherical lens with positive optical power, the object side surface S5 of the third lens is convex, and the image side surface S6 of the third lens is convex; the fourth lens L4 is an aspherical lens with negative optical power, the object side surface S7 of the fourth lens is concave, and the image side surface S8 of the fourth lens is concave; the fifth lens L5 is an aspherical lens with positive optical power, the object side surface S9 of the fifth lens is concave, and the image side surface S10 of the fourth lens is concave; The side surface S9 is a convex surface, and the image side surface S10 of the fifth lens is a convex surface; the sixth lens L6 is a spherical lens with positive focal power, the object side surface S11 of the sixth lens is a convex surface, and the image side surface S13 of the seventh lens is a concave surface, and the sixth lens L6 and the seventh lens L7 form a cemented lens, and the cemented surface is S12; the eighth lens L8 is an aspherical lens with positive focal power, the object side surface S14 of the eighth lens is a concave surface, and the image side surface S15 of the eighth lens is a convex surface; the object side surface S16 and the image side surface S17 of the filter G1 are both planes.

[0090] Specifically, the design parameters of each lens of the optical lens provided in this embodiment are shown in Table 1-1.

[0091] Table 1-1

[0092]

[0093] The surface coefficients of the aspherical surfaces of the optical lens in this embodiment are shown in Table 1-2.

[0094] Table 1-2

[0095]

[0096] Figure 2 The distortion curve of Example 1 is shown, which represents the F-θ distortion of different field angles on the imaging plane, the horizontal axis represents the distortion value (unit: %), and the vertical axis represents the half field angle (unit: °). It can be seen from the figure that the distortion value corresponding to the maximum field angle is controlled in a range greater than +20%, indicating that the optical lens has a large positive distortion.

[0097] Figure 3 The modulation transfer function (MTF) 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 0.2 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.

[0098] Example 2

[0099] See also Figure 4 , shown is a schematic diagram of the structure of the optical lens provided in Example 2 of the present invention. The optical lens of this embodiment is substantially the same as that of the above-mentioned Example 1, except that parameters such as the curvature radius of each lens surface, the thickness of each lens, and the aspheric coefficient of each lens are different.

[0100] Specifically, the design parameters of each lens of the optical lens provided in this embodiment are shown in Table 2-1.

[0101] Table 2-1

[0102]

[0103] The surface coefficients of the aspherical surfaces of the optical lens in this embodiment are shown in Table 2-2.

[0104] Table 2-2

[0105]

[0106] Figure 5 , Figure 6 The distortion curve and modulation transfer function (MTF) curve of Example 2 are shown respectively. It can be seen from the figure that the distortion value corresponding to the maximum field angle is controlled in a range greater than +20%, indicating that the optical lens has a large positive distortion; the MTF value of the optical lens is above 0.1 in the entire 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.

[0107] Example 3

[0108] See also Figure 7 , shown is a schematic diagram of the structure of the optical lens provided in Example 3 of the present invention. The optical lens of this embodiment is substantially the same as that of the above-mentioned Example 1, except that parameters such as the curvature radius of each lens surface, the thickness of each lens, and the aspheric coefficient of each lens are different.

[0109] Specifically, the design parameters of each lens of the optical lens provided in this embodiment are shown in Table 3-1.

[0110] Table 3-1

[0111]

[0112] The surface coefficients of the aspherical surfaces of the optical lens in this embodiment are shown in Table 3-2.

[0113] Table 3-2

[0114]

[0115] Figure 8 , Fig. 9 The distortion curve and modulation transfer function (MTF) curve of Example 3 are shown respectively. It can be seen from the figure that the distortion value corresponding to the maximum field angle is controlled in a range greater than +20%, indicating that the optical lens has a large positive distortion; the MTF value of the optical lens is above 0.1 in the entire 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.

[0116] Example 4

[0117] See also Fig.10, shown is a schematic diagram of the structure of the optical lens provided in Example 4 of the present invention. The optical lens of this embodiment is substantially the same as that of the above-mentioned Example 1, except that the parameters such as the curvature radius of each lens surface, the thickness of each lens, and the aspheric coefficient of each lens are different.

[0118] Specifically, the design parameters of each lens of the optical lens provided in this embodiment are shown in Table 4-1.

[0119] Table 4-1

[0120]

[0121] The surface coefficients of the aspherical surfaces of the optical lens in this embodiment are shown in Table 4-2.

[0122] Table 4-2

[0123]

[0124] Fig.11 , Fig.12 The distortion curve and modulation transfer function (MTF) curve of Example 4 are shown respectively. It can be seen from the figure that the distortion value corresponding to the maximum field angle is controlled in a range greater than +20%, indicating that the optical lens has a large positive distortion; the MTF value of the optical lens is above 0.1 in the entire 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.

[0125] Example 5

[0126] See also Fig.13 , shown is a schematic diagram of the structure of the optical lens provided in Example 5 of the present invention. The optical lens of this embodiment is substantially the same as that of the above-mentioned Example 1, except that parameters such as the curvature radius of each lens surface, the thickness of each lens, and the aspheric coefficient of each lens are different.

[0127] Specifically, the design parameters of each lens of the optical lens provided in this embodiment are shown in Table 5-1.

[0128] Table 5-1

[0129]

[0130] The surface coefficients of the aspherical surfaces of the optical lens in this embodiment are shown in Table 5-2.

[0131] Table 5-2

[0132]

[0133] Fig.14 , Fig.15 The distortion curve and modulation transfer function (MTF) curve of Example 5 are shown respectively. It can be seen from the figure that the distortion value corresponding to the maximum field angle is controlled in a range greater than +20%, indicating that the optical lens has a large positive distortion; the MTF value of the optical lens is above 0.1 in the entire 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.

[0134] Please refer to Table 6, which shows the optical characteristics corresponding to the optical lenses provided in the above 6 embodiments, including the effective focal length f of the optical lens, the maximum field of view FOV, the pupil diameter EPD, the total optical length TTL, the aperture value FNO, the image height IH corresponding to the maximum field of view angle, the main ray incident angle CRA, the optical back focus BFL and the numerical value corresponding to each conditional expression in each embodiment.

[0135] Table 6

[0136]

[0137] To summarize, the optical lens in the embodiment of the present invention adopts eight lenses with optical power. By reasonably allocating the optical power of each lens, reasonably matching the surface shape of each lens, reasonably setting the thickness of each lens and the distance between each lens, reasonably setting the position of the aperture, and setting the optical lens to have a large positive distortion, it is possible to achieve a balance of a large field of view (maximum FOV is 213°), a large aperture (minimum FNO is 2.00) and a high pixel, thereby meeting the use requirements of vehicle-mounted lenses.

[0138] 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.

[0139] The above-described 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 present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, comprising eight lenses, characterized in that: Along the optical axis from the object side to the imaging surface, it includes: A first lens having negative optical power, wherein the object side surface is convex and the image side surface is concave; a second lens having negative optical power, wherein the object side surface is concave and the image side surface is concave; a third lens having positive refractive power, whose object-side surface is convex and image-side surface is convex; a fourth lens element having negative optical power, whose object-side surface is concave and image-side surface is concave; a fifth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; a sixth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; a seventh lens element having negative optical power, whose object-side surface is concave and whose image-side surface is concave; an eighth lens having positive refractive power, whose object-side surface is concave and whose image-side surface is convex; Wherein, the curvature radius R3 of the object side surface and the curvature radius R4 of the image side surface of the second lens satisfy: 1.2<(R3-R4) / (R3+R4); The curvature radius R15 of the object side surface and the curvature radius R16 of the image side surface of the eighth lens satisfy: 0.2<(R15-R16) / (R15+R16)<0.

6.

2. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy the following conditions: 16.0<TTL / f<23.

0.

3. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens and the image height IH corresponding to the maximum field angle of the optical lens satisfy the following: 4.00<TTL / IH<4.

80.

4. The optical lens according to claim 1, characterized in that: The image height IH corresponding to the maximum field angle of the optical lens, the effective focal length f of the optical lens, and the arc value θ of the maximum half field angle of the optical lens satisfy: 1.15<(IH / 2) / (f×θ).

5. The optical lens according to claim 1, characterized in that: The image height IH corresponding to the maximum field angle of the optical lens and the effective focal length f of the optical lens satisfy the following: 4.0<IH / f.

6. The optical lens according to claim 1, characterized in that: The optical back focus BFL of the optical lens and the effective focal length f of the optical lens satisfy the following condition: 1.0<BFL / f.

7. The optical lens according to claim 1, characterized in that: The effective focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: f1 / f<-10.

0.

8. The optical lens according to claim 1, characterized in that: The effective focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: f2 / f<-5.

5.

9. The optical lens according to claim 1, characterized in that: The effective focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 3.3<f3 / f.

10. The optical lens according to claim 1, characterized in that: The effective focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -2.0<f4 / f<-1.

6.

11. The optical lens according to claim 1, characterized in that: The effective focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy the following: 2.0<f5 / f<2.

5.

12. The optical lens according to claim 1, characterized in that: The effective focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy the following: 1.6<f8 / f<2.

0.

13. The optical lens according to claim 1, characterized in that: The total optical length TTL of the optical lens and the sum ΣCT of the center thicknesses of the first lens to the eighth lens along the optical axis respectively satisfy: 0.28<ΣCT / TTL<0.

45.

14. The optical lens according to claim 1, characterized in that: An air gap CT23 between the image side surface of the second lens and the object side surface of the third lens on the optical axis and a total optical length TTL of the optical lens satisfy the following relationship: 0.28<CT23 / TTL<0.40.

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