Optical lens

Abstract

The present invention provides an optical lens, which has eight lenses in total, and includes 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; a third lens with positive optical power; a fourth lens with positive optical power, whose object side surface is convex; a fifth lens with positive optical power, whose object side surface is convex and whose image side surface is concave; a sixth lens with negative optical power, whose object side surface is convex and whose image side surface is concave; a seventh lens with positive optical power, whose object side surface is convex; an eighth lens with negative optical power, whose object side surface and image side surface are both concave. The optical lens provided by the present invention improves the imaging quality of the optical lens through the reasonable configuration of the surface types of each lens and the reasonable matching of the optical power, so that the lens has one or more advantages such as ultra-wide angle, high pixel, and high imaging quality.

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] With the continuous advancement of existing image processing algorithms and AI technologies, high-definition wide-angle lenses, as a special type of optical lenses, are widely used in various fields such as sports cameras, car lenses and smart homes. Therefore, the requirements for high-definition wide-angle lenses are becoming higher and higher.

[0003] However, existing high-definition wide-angle lens equipment still has many shortcomings. For example, the lens is too long, large in size, heavy in weight, and not convenient to carry; the increased field of view of the lens makes it difficult to correct system aberrations and reduces the imaging quality; the relative aperture of the lens is small, the light transmission performance is poor, and it cannot adapt to darker environments; and the existing lens imaging target surface is small, which makes it difficult to meet market demand.

[0004] Therefore, it is necessary to develop an optical lens with one or more advantages such as ultra-wide angle, high imaging quality, and high pixel, so as to better meet the market's high demand for high-definition wide-angle lenses. Summary of the invention

[0005] In view of the above problems, an object of the present invention is to provide an optical lens having one or more advantages such as ultra-wide angle, high pixel, and high imaging quality.

[0006] The present invention provides an optical lens, which comprises eight lenses in total, and 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; a third lens with positive optical power; a fourth lens with positive optical power, whose object side surface is convex; a fifth lens with positive optical power, whose object side surface is convex and whose image side surface is concave; a sixth lens with negative optical power, whose object side surface is convex and whose image side surface is concave; a seventh lens with positive optical power, whose object side surface is convex; and an eighth lens with negative optical power, whose object side surface and image side surface are both concave.

[0007] Further preferably, a reflective element is provided between the third lens and the fourth lens, and the surface of the reflective element facing the object side is an incident surface, and the surface facing the imaging surface is an exit surface.

[0008] Further preferably, the effective focal length f of the optical lens and the total optical length TTL satisfy: TTL / f<24.0.

[0009] Further preferably, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: TTL / IH<9.0.

[0010] Further preferably, the effective focal length f of the optical lens, the arc θ of the maximum half field of view angle, and the real image height IH corresponding to the maximum field of view angle satisfy: 0.75<(IH / 2) / (f×θ)<0.90.

[0011] Further preferably, the effective focal length f of the optical lens and the optical back focal length BFL satisfy: BFL / f>0.9.

[0012] Further preferably, the effective focal length f of the optical lens, the maximum field of view FOV and the real image height IH corresponding to the maximum field of view angle satisfy: 65.0<(f×FOV) / IH.

[0013] Further preferably, the real image height IHm corresponding to the central field angle of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 0.55 <IHm / IH。

[0014] Further preferably, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: f1 / f<-6.0.

[0015] Further preferably, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: f2 / f<-3.0.

[0016] Further preferably, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 7.5 <f3 / f。

[0017] Further preferably, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 6.0 <f4 / f。

[0018] Further preferably, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 4.0 <f5 / f<7.0。

[0019] Further preferably, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -2.8 <f6 / f<-1.5。

[0020] Further preferably, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.5 <f7 / f<2.1。

[0021] Further preferably, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: f8 / f<-7.0.

[0022] Further preferably, the curvature radius R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 9.0 <R10 / f。

[0023] Further preferably, a curvature radius R9 of the object side surface and a curvature radius R10 of the image side surface of the fifth lens satisfy: -0.8<(R9-R10) / (R9+R10)<-0.5.

[0024] Further preferably, the object side surface curvature radius R15 and the image side surface curvature radius R16 of the eighth lens satisfy: 1.8<(R15-R16) / (R15+R16).

[0025] Further preferably, the spacing distance CT34 between the third lens and the fourth lens on the optical axis and the effective focal length f of the optical lens satisfy: 4.5CT34 / f<7.0.

[0026] Further preferably, the sum ΣCT of the center thickness of each lens from the first lens to the eighth lens and the total optical length TTL of the optical lens satisfy: 0.35<ΣCT / TTL<0.50.

[0027] The optical lens provided by the present invention improves the imaging quality of the optical lens, reduces aberrations, and improves the imaging quality of the optical lens through the reasonable configuration of the surface shapes of each lens and the reasonable matching of the optical focal length, so that the lens has one or more advantages such as ultra-wide angle, high pixel, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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:

[0029] Figure 1 Schematic diagram of the structure of the optical lens in the example of the present invention.

[0030] Figure 2 Schematic diagram of the structure of the optical lens in Example 1 of the present invention.

[0031] Figure 3 This is the MTF curve diagram of the optical lens in Example 1 of the present invention.

[0032] Figure 4 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0033] Figure 5 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0034] Figure 6 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0035] Figure 7 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0036] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Example

[0045] See also Figure 1 , is a schematic diagram of the structure of the optical lens in an example of the present invention. Figure 1 The difference between (A) and (B) is that the structure of the prism in (B) is a folding structure. The reason for this phenomenon is that during the design process, a folding coordinate breakpoint is added to the prism, and the target surface is changed into a reflector of the folded light path, so that the coordinate system of the optical lens behind the prism changes, resulting in the lens curvature radius R and thickness D / distance L behind the prism being opposite numbers. It should be noted that the purpose of transforming the optical lens data of the folding structure into the optical lens of the linear structure is to unify the coordinate system to facilitate the description and calculation of the optical lens, and it cannot be understood as a limitation on the scope of the patent of the present invention. Figure 1 The difference between (A) and (C) is that the prism structure is eliminated in (C). The reason for this phenomenon is that the optical lens assembly requirements are taken into consideration during the design process, and the optical path of the optical lens is designed as a return structure, which is conducive to assembly in a small space. It should be noted that the purpose of adding the return structure is to improve the compactness of the optical lens and avoid the optical lens being too large to be easy to assemble, and it cannot be understood as a limitation on the scope of the patent of this invention.

[0046] The optical lens provided by the embodiment of the present invention comprises eight lenses in total, which are, in order from the object side to the imaging surface along the optical axis, 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.

[0047] In some embodiments, the first lens may have a negative optical power, which is beneficial to reduce the inclination angle of the incident light, thereby effectively sharing the large field of view on the object side. The object side of the first lens is convex, and the image side is concave, which is beneficial to collect the edge field of view light as much as possible into the rear optical lens, and realize large-angle light collection.

[0048] In some embodiments, the second lens may have a negative focal length, which helps to smoothly transition the light, expand the field of view of the optical imaging lens, reduce the difficulty of the rear lens in correcting distortion and chromatic aberration, and improve the image quality of the optical imaging lens. The object side of the second lens is concave, which is conducive to changing the trend of the edge field of view light, so that the light entering the second lens has a clear light turn, which is conducive to the rear lens to correct the edge field of view light and improve the imaging quality of the optical lens.

[0049] In some embodiments, the third lens may have a positive focal length, which is beneficial to improving the light convergence ability of the optical lens, while balancing various aberrations produced by the optical lens, and improving the imaging quality of the optical lens. The object side of the third lens is a convex surface, which is beneficial to reducing the angle between the edge incident light and the normal line of the object side of the third lens, avoiding light divergence and reducing the sensitivity of the optical lens.

[0050] In some embodiments, the fourth lens may have a positive focal length, which is beneficial to improving the light convergence ability of the optical lens, while being able to balance various aberrations of the optical lens and improve the imaging quality of the optical lens. The object side of the fourth lens is a convex surface, which can reduce the degree of deflection of the light emitted by the third lens, which is beneficial to the smooth passage of light, reduces the light energy loss when passing through the fourth lens, and improves the relative illumination of the optical lens.

[0051] In some embodiments, the fifth lens may have a positive focal length, which is beneficial to improving the light convergence ability of the optical lens, while being able to balance various aberrations of the optical lens and improving the imaging quality of the optical lens. The object side of the fifth lens is a convex surface, and the image side is a concave surface, which can further converge the light emitted from the fifth lens, reduce the aperture of the rear end lens, and gather the light to reach the imaging surface, which is beneficial to compressing the total length of the optical lens.

[0052] In some embodiments, the sixth lens may have a negative optical power, which is conducive to diverging the light converged by the fourth lens and the fifth lens, so that it can reach a higher imaging position. The object side of the sixth lens is convex, and the image side is concave, which can diverge the light converged by the front lens, so that it can reach a higher imaging position, appropriately stretch the optical path of each field of view light, and smoothly diverge to the rear lens.

[0053] In some embodiments, the seventh lens may have positive focal length, which is beneficial for further focusing light, and can correct chromatic aberration when used with the sixth lens having negative focal length. The object side of the seventh lens is convex, which can collect light emitted by the sixth lens.

[0054] In some embodiments, the eighth lens may have a negative optical power, which is conducive to diverging the incident light, making the peripheral light and the central light turn upward and reach a higher imaging position. The eighth lens has a concave object side and a concave image side, which can diverge the light incident from the front lens, making the edge field light and the central light turn upward and reach a higher imaging position; at the same time, the edge field light is converged, which can reduce the incident angle of the light entering the chip, which helps to improve the relative illumination of the optical lens.

[0055] In some embodiments, the optical lens may further include an aperture, which may be located between the fifth lens and the sixth lens. It is understandable that the aperture is used to limit the amount of light entering to change the brightness of the image. In addition, when the aperture is located between the fifth lens and the sixth lens, the aperture can reasonably distribute the functions of the first lens to the eighth lens. For example, the first lens, the second lens and the fifth lens can be used to receive light to a greater extent and reduce the generation of various aberrations. The sixth lens to the eighth lens can be used to correct the aberration, which is beneficial to balance the structure of the entire optical system. In addition, when the aperture is located between the fifth lens and the sixth lens, it is convenient to correct the aperture aberration.

[0056] In some embodiments, the optical lens may further include a filter, which is disposed between the eighth lens and the imaging surface. 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.

[0057] In some embodiments, in order to reduce the size of the optical lens, a reflective element with no optical power for folding the light path may be provided between the third lens and the fourth lens, and the reflective element is a prism. The surface of the prism facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface, and both the incident surface and the exit surface are planes. The prism may be a right-angle prism, and the light from the object side enters the prism from the incident surface, is reflected by the reflective surface, and then is emitted from the exit surface. By bending the light path through the prism, the thickness of the lens can be effectively shortened.

[0058] In some embodiments, the effective focal length f of the optical lens and the total optical length TTL satisfy: TTL / f<24.0. Meeting the above range indicates that the optical length of the optical lens can be effectively limited, which is conducive to miniaturization of the optical lens.

[0059] In some embodiments, the total optical length TTL of the optical lens and the real image height IH corresponding to the maximum field of view satisfy: TTL / IH<9.0. Meeting the above range indicates that the total optical length and image plane height of the optical lens can be effectively limited, which is conducive to achieving a short total optical length and a large image height.

[0060] In some embodiments, the effective focal length f of the optical lens, the radian θ of the maximum half field of view angle, and the true image height IH corresponding to the maximum field of view angle satisfy: 0.75 < (IH / 2) / (f×θ) < 0.90. Meeting the above range indicates that the structure has high design flexibility, can effectively control the distortion range, and meet the requirements of different distortion algorithms.

[0061] In some embodiments, the effective focal length f of the optical lens and the back focal length BFL satisfy: BFL / f > 0.9. Meeting the above range can make the lens have a large back focal length, which is beneficial to the assembly of the module, reduces interference, and improves the production yield.

[0062] In some embodiments, the effective focal length f of the optical lens, the maximum field of view angle FOV, and the true image height IH corresponding to the maximum field of view angle satisfy: 65.0 < (f×FOV) / IH. Meeting the above range is beneficial to meeting the requirements of a large field of view of the optical lens, achieving a large image height and a long focal length at the same time, and is more conducive to achieving small distortion and improving the imaging quality of the optical lens.

[0063] In some embodiments, the true image height IHm corresponding to the central field of view angle of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 0.55 < IHm / IH. Meeting the above range can effectively increase the proportion of the central field of view imaging range in the entire imaging range. Compared with lenses with the same field of view angle, the proportion of the central field of view imaging range in the entire imaging range is larger, and more detailed information can be obtained.

[0064] In some embodiments, the focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: f1 / f < -6.0. Meeting the above range can make the first lens have an appropriate negative optical power, avoid excessive concentration of negative optical power, and at the same time is beneficial to increasing the field of view angle, and is beneficial to collecting as much marginal field of view light as possible into the rear optical lens to achieve large-angle light collection.

[0065] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: f2 / f < -3.0. Meeting the above range can make the second lens have an appropriate negative optical power, increase the field of view angle, and improve the imaging quality of the optical lens.

[0066] In some embodiments, the focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 7.5 < f3 / f. Meeting the above range can make the third lens have an appropriate positive optical power, which is beneficial to improving the light converging ability of the optical lens, and at the same time can balance various aberrations generated by the optical lens and improve the imaging quality of the optical lens.

[0067] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 6.0 < f4 / f. Satisfying the above range can make the fourth lens have an appropriate positive optical power, which is beneficial to improving the light converging ability of the optical lens. At the same time, it can balance the aberration of the optical lens and improve the imaging quality of the optical lens.

[0068] In some embodiments, the focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 4.0 < f5 / f < 7.0. Satisfying the above range can make the fifth lens have an appropriate positive optical power, which is beneficial to improving the light converging ability of the optical lens. At the same time, it can balance the aberration of the optical lens and improve the imaging quality of the optical lens.

[0069] In some embodiments, the focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -2.8 < f6 / f < -1.5. Satisfying the above range can make the sixth lens have an appropriate negative optical power, which is beneficial to diverging the light converged by the fourth lens and the fifth lens and increasing the image height of the optical lens.

[0070] In some embodiments, the focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.5 < f7 / f < 2.1. Satisfying the above range can make the seventh lens have a suitable positive optical power, which is beneficial to suppressing the angle of the light emerging from the edge field of view.

[0071] In some embodiments, the focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: f8 / f < -7.0. Satisfying the above range can make the eighth lens have a suitable negative optical power, which is beneficial to diverging the light, making the peripheral light and the central light turn up and reach a higher imaging position.

[0072] In some embodiments, the radius of curvature R10 of the image side of the fifth lens and the effective focal length f of the optical lens satisfy: 9.0 < R10 / f. Satisfying the above range can further converge the light emerging from the fifth lens, reduce the aperture of the rear lens, and converge the light to reach the imaging surface, which is beneficial to compressing the total length of the optical lens.

[0073] In some embodiments, the radius of curvature R9 of the object side of the fifth lens and the radius of curvature R10 of the image side satisfy: -0.8 < (R9 - R10) / (R9 + R10) < -0.5. Satisfying the above range can further converge the light emerging from the fourth lens, reduce the aperture of the rear lens, and converge the light to reach the imaging surface, which is beneficial to reducing the optical total length and realizing the miniaturization of the optical lens.

[0074] In some embodiments, the radius of curvature R15 of the object side surface of the eighth lens and the radius of curvature R16 of the image side surface satisfy: 1.8 < (R15 - R16) / (R15 + R16). Satisfying the above range can diverge the light rays incident on the front lens, causing the marginal field light rays and the central light rays to turn upwards and reach a higher imaging position.

[0075] In some embodiments, the spacing distance CT34 between the third lens and the fourth lens on the optical axis and the effective focal length f of the optical lens satisfy: 4.5 < CT34 / f < 7.0. Satisfying the above range can achieve a retrofolding structure of the optical lens and reduce the thickness of the lens.

[0076] In some embodiments, the sum ∑CT of the central thicknesses of the lenses from the first lens to the eighth lens and the overall optical length TTL of the optical lens satisfy: 0.35 < ∑CT / TTL < 0.50. Satisfying the above range is beneficial to compressing the overall length and volume of the optical lens and maintaining the miniaturization of the optical lens.

[0077] In some embodiments, the optical lens satisfies the conditional formula: FOV > 190°, 1.4 mm < f < 2.0 mm, 3.8 mm < IH < 6.0 mm, where FOV represents the maximum field of view angle of the optical lens, f represents the effective focal length of the optical lens, and IH represents the true image height corresponding to the maximum field of view angle of the optical lens. Satisfying the above conditions indicates that the optical lens provided by the embodiments of the present invention has at least one of the characteristics of an ultra-wide angle and a large image plane.

[0078] In some embodiments, the sixth lens and the seventh lens can be glued together 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 processing difficulty of the optical lens and improving the assembly yield of the optical lens.

[0079] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens can be 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 second lens, the third lens, and the eighth lens in the optical lens provided by the present invention can be aspherical lenses, and the first lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can be spherical lenses.

[0080] In various embodiments of the present invention, when the lens is an aspherical lens, the surface shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0081] ;

[0082] 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.

[0083] 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.

[0084] Example 1

[0085] See also Figure 2 , 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 along the optical axis: a first lens L1, a second lens L2, a third lens L3, a prism, a fourth lens L4, a fifth lens L5, an aperture ST, a sixth lens L6, a seventh lens L7, an eighth lens L8 and a filter G1.

[0086] Among them, the first lens L1 has negative focal power, its object side surface S1 is convex, and the image side surface S2 is concave; the second lens L2 has negative focal power, its object side surface S3 and image side surface S4 are both concave; the third lens L3 has positive focal power, its object side surface S5 and image side surface S6 are both convex; the surface of the prism facing the object side is the incident surface, and the surface facing the imaging surface is the exit surface, and the incident surface and the exit surface are both planes; the fourth lens L4 has positive focal power, its object side surface S7 is convex, and the image side surface S8 is concave; the fifth lens L5 has positive focal power, its object side surface S9 is a convex surface, and the image side surface S10 is a concave surface; the sixth lens L6 has negative optical power, its object side surface S11 is a convex surface, and the image side surface S12 is a concave surface; the seventh lens L7 has positive optical power, its object side surface S12 is a convex surface, and the image side surface S13 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 has negative optical power, and its object side surface S14 and image side surface S15 are both concave surfaces; the object side surface S16 and the image side surface S17 of the filter G1 are both planes; and the imaging surface S18 is a plane.

[0087] The first lens L1, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7 are glass spherical lenses; the second lens L2, the third lens L3 and the eighth lens L8 are glass aspherical lenses.

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

[0089] Table 1-1

[0090]

[0091] The surface parameters of the aspherical lens of the optical lens in Example 1 are shown in Table 1-2.

[0092] Table 1-2

[0093]

[0094] In this embodiment, Figure 3 The 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 0.45 in the entire field of view, and in the range of 0 to 230 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.

[0095] Example 2

[0096] See also Figure 4 , which is a schematic diagram of the structure of the optical lens provided in Example 2 of the present invention. Compared with Example 1, this embodiment is different mainly in optical parameters such as the curvature radius of each lens surface and the lens thickness.

[0097] The relevant parameters of each lens in the optical lens in Example 2 are shown in Table 2-1.

[0098] Table 2-1

[0099]

[0100] The surface parameters of the aspherical lens of the optical lens in Example 2 are shown in Table 2-2.

[0101] Table 2-2

[0102]

[0103] from Figure 5 It can be seen that the MTF value of this embodiment is above 0.55 in the whole field of view. In the range of 0 to 230 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has excellent imaging quality and excellent detail resolution capability in both low-frequency and high-frequency conditions.

[0104] Example 3

[0105] See also Figure 6 , shown is a schematic diagram of the structure of the optical lens provided in Example 3 of the present invention. Compared with Example 1, this embodiment is different mainly in optical parameters such as the curvature radius of each lens surface and the lens thickness.

[0106] The relevant parameters of each lens in the optical lens in Example 3 are shown in Table 3-1.

[0107] Table 3-1

[0108]

[0109] The surface parameters of the aspherical lens of the optical lens in Example 3 are shown in Table 3-2.

[0110] Table 3-2

[0111]

[0112] from Figure 7 It can be seen that the MTF value of this embodiment is above 0.4 in the whole field of view. In the range of 0 to 230 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.

[0113] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the aperture value Fno, the real image height IH, the entrance pupil diameter EPD, the main ray incident angle CRA at the maximum image height and the maximum field of view FOV of the optical lens, as well as the numerical values ​​corresponding to each conditional expression in each embodiment.

[0114] Table 4

[0115]

[0116] In summary, the optical lens provided by the present invention improves the imaging quality of the optical lens, reduces aberrations, and improves the imaging quality of the optical lens through the reasonable configuration of the surface shapes of each lens and the reasonable matching of the optical focal length, so that the lens has one or more advantages such as ultra-wide angle, high pixel, and high imaging quality.

[0117] 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.

[0118] 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 eight lenses, characterized in that: It successively includes from the object side to the imaging plane along the optical axis: A first lens with a negative optical power, whose object side is convex and image side is concave; A second lens with a negative optical power, whose object side is concave; A third lens with a positive optical power; A fourth lens with a positive optical power, whose object side is convex; A fifth lens with a positive optical power, whose object side is convex and image side is concave; A sixth lens with a negative optical power, whose object side is convex and image side is concave; A seventh lens with a positive optical power, whose object side is convex; An eighth lens with a negative optical power, whose object side and image side are both concave; The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -7.68 ≤ f2 / f < -3.0; The focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 6.0 < f4 / f ≤ 10.

68.

2. The optical lens according to claim 1, characterized in that: A reflection element is provided between the third lens and the fourth lens. The surface facing the object side of the reflection element is the incident surface, and the surface facing the imaging plane is the exit surface; The focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -7.68 ≤ f2 / f ≤ -3.16; The focal length f3 of the third lens and the effective focal length f of the optical lens satisfy: 7.5 < f3 / f ≤ 52.06; The focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: 6.24 ≤ f4 / f ≤ 10.68; The focal length f6 of the sixth lens and the effective focal length f of the optical lens satisfy: -2.8 < f6 / f < -1.5; The focal length f7 of the seventh lens and the effective focal length f of the optical lens satisfy: 1.5 < f7 / f < 2.

1.

3. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the optical total length TTL satisfy: 18.06 ≤ TTL / f < 24.

0.

4. The optical lens according to claim 1, characterized in that: The optical total length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle satisfy: 6.11 ≤ TTL / IH < 9.

0.

5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens, the radian θ of the maximum half field of view angle and the true image height IH corresponding to the maximum field of view angle satisfy: 0.75 < (IH / 2) / (f×θ) < 0.

90.

6. The optical lens according to claim 1, characterized in that: The effective focal length f, 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 satisfy: 65.0 < (f×FOV) / IH ≤ 74.

23.

7. The optical lens according to claim 1, characterized in that: The focal length f1 of the first lens and the effective focal length f of the optical lens satisfy: -8.79 ≤ f1 / f < -6.

0.

8. The optical lens according to claim 1, characterized in that: The focal length f5 of the fifth lens and the effective focal length f of the optical lens satisfy: 4.0 < f5 / f < 7.

0.

9. The optical lens according to claim 1, characterized in that: The focal length f8 of the eighth lens and the effective focal length f of the optical lens satisfy: -35.09 ≤ f8 / f < -7.

0.

10. The optical lens according to claim 1, characterized in that: The radius of curvature R10 of the image side of the fifth lens and the effective focal length f of the optical lens satisfy: 9.0 < R10 / f ≤ 16.

4.

11. The optical lens according to claim 1, characterized in that: The radius of curvature R9 of the object side of the fifth lens and the radius of curvature R10 of the image side satisfy: -0.8 < (R9 - R10) / (R9 + R10) < -0.

5.

12. The optical lens according to claim 1, characterized in that: The object side curvature radius R15 and the image side curvature radius R16 of the eighth lens satisfy: 1.8<(R15-R16) / (R15+R16).

13. The optical lens according to claim 1, characterized in that: The distance CT34 between the third lens and the fourth lens on the optical axis and the effective focal length f of the optical lens satisfy: 4.5 <CT34 / f<7.0。 14. The optical lens according to claim 1, characterized in that: The sum ΣCT of the center thickness of each lens from the first lens to the eighth lens and the total optical length TTL of the optical lens satisfy the following: 0.35<ΣCT / TTL<0.50.

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